WO2007072470A1

WO2007072470A1 - Apparatus and cartridge for storage of compressed hydrogen gas and system for filling the cartridge

Info

Publication number: WO2007072470A1
Application number: PCT/IL2006/001082
Authority: WO
Inventors: Valery G. Gnedenko; Igor V. Goryachev; Nikolay Zhevago
Original assignee: C. En. Limited; Stern, Moshe
Priority date: 2005-12-22
Filing date: 2006-09-14
Publication date: 2007-06-28

Abstract

An apparatus for storage of compressed hydrogen gas is provided. The apparatus includes a sealed housing having an outlet pipe coupled to the housing and equipped with a controllable discharge valve. The sealed housing defines a chamber that includes a cartridge comprising a plurality of cylindrical voids containing said compressed hydrogen gas. The apparatus also includes a hydrogen liberating tool configured for controllable liberating the hydrogen gas from the cartridge into a volume of the chamber that is not occupied by the cartridge. The apparatus is controlled by a control system operatively coupled to the controllable discharge valve and the hydrogen liberating tool, and configured for controlling operation thereof. According to another aspect of the invention, there are provided a system and method for filling the cartridge. The filling includes vacuumizing a chamber into which the cartridge is placed; preparing the cartridge in order to let the hydrogen gas diffuse into the cylindrical voids; and controlled hydrogen gas compressing in the chamber over a predetermined compression time interval until the pressure in the chamber reaches a predetermined pressure value.

Description

Apparatus and cartridge for storage of compressed hydrogen gas and system for filling the cartridge

FIELD OF THE INVENTION

The present invention relates generally to fuel storage, and in particular, to accumulation and storage of hydrogen gas.

BACKGROUND OF THE INVENTION It is well-known that hydrogen is a very high energy density element and clean- burning fuel. The energy density of hydrogen, which is around 120 MJ/kg, is more than double that of most conventional fuels, e.g., natural gas: 43 MJ/kg and gasoline 44.4 MJ/kg. Hydrogen can be combined with oxygen through combustion, or through fuel cell mediated oxidation/reduction reactions, to produce heat, or electrical power. The primary product of this reaction is water, which is non-polluting and can be recycled to regenerate hydrogen and oxygen.

Currently;, hydrogen energetics is the focus of interest in nuclear industry, motor transport, auto industry, chemical industry, aerospace industry, portable power sources industry (cellular phones, computers, home appliances), etc. In particular, the transport sector is a consumer of about half of the world's crude oil production. Moreover, in large metropolitan agglomerations worldwide, road traffic represents one of the most important and fastest growing emission sources for both pollutants and noise. Hydrogen as a new vehicle fuel provides the opportunity for both, the reduction or avoidance of polluting emissions and the drastic reduction of the noise level produced. Already hydrogen operated internal combustion engines have a low noise potential and significantly reduced pollutant levels. Therefore, the transport sector of the economy is intensively adopting the use of hydrogen fuel. This can help solve environmental problems, especially in large megapolises and industrial regions.

One of the problems of hydrogen energetics is safe storage and delivery of hydrogen fuel to a combustion cell. Most generally, there are three basic hydrogen storage techniques. Hydrogen can be stored as a cryogenic liquid, as a compressed gas in a large vessel, or bound chemically in a compound such as a metal Hydride.

The infrastructural requirements for liquid hydrogen storage are high due to the very low cryogenic temperatures of -253⁰C (20 K). Thus, liquid storage systems, transfer pipes and refueling couplings require significant thermal insulation in order to maintain the liquid state and avoid or retard premature rapid evaporation of liquid hydrogen.

Compressed hydrogen storage is the most common method for hydrogen storage. Typically the pressure levels are in the order of 20 MPa - 70 MPa. Today's storage vessels usually are manufactured in fiber composite materials design in order to reduce structural weight. An internal shell is made of stainless steel or aluminum and is wrapped with glass and/or carbon fibers. The tank designs are also known which are made completely from plastic materials. Nevertheless, most compressed gaseous storage tanks are relatively large and heavy. Moreover, existing accumulation techniques with compressed gaseous hydrogen in tanks provide a relatively low hydrogen weight content (the ratio of the weight of hydrogen in accumulator to the weight of accumulator), i.e., less than 10 weight %, and there are certain restrictions for further growth of this parameter along with low explosion protection.

The storage of gaseous hydrogen in metal hydrides makes use of depositing hydrogen in metal alloys. The hydrogen accumulation and storage techniques are relatively explosion-proof, because hydrogen features no excess pressure. Disadvantages of metal hydride storage are that depending on the type of metal alloy, more or less elevated temperatures are needed to set hydrogen free again, and the low mass related storage density. Usually, the weight content of hydrogen is less than 4.5%. Conceptually, also storage in other materials can be achieved by physical sorption. For example, storage of hydrogen in carbon nano-fibers is known. However, due to the weaker bonding of hydrogen in these solids the storage temperatures have to be lower than those for storage as metal hydrides.

It is known that hydrogen can be safely stored in hollow glass microspheres. The amount of hydrogen in each individual microsphere is very small, preventing the possibility of explosions by improper handling or during accidents.

If heated, the microsphere permeability to hydrogen will increase. Hydrogen can diffuse into the hollow cores of the microspheres through the thin glass walls at practical rates at temperatures between 100⁰C and 400⁰C. This provides the ability to fill the microspheres with gas by placing the microspheres in high-temperature and high pressure environments. Once cooled, the microspheres lock the hydrogen inside since the diffusion rate is drastically lower at room temperature. A subsequent increase in temperature will increase the diffusion rate. Thus, the hydrogen trapped in the microspheres can be released by subsequently increasing the temperature.

For example, U.S. Pat. No. 4,328,768 describes a fuel storage and delivery system wherein hollow microspheres filled with hydrogen gas are stored in a fuel storage chamber at pressures of 400 atm. From the fuel storage chamber the microspheres are directed through a heated delivery chamber wherein hydrogen gas is freed by diffusion and delivered to an engine, after which the substantially emptied microspheres are delivered to a second storage chamber. The substantially emptied microspheres are removed by mechanical means, such as a pump, to a storage chamber from which they can be removed for refilling.

SUMMARY OF THE INVENTION

Despite known techniques in the area of accumulation and storage of hydrogen, there is still a need in the art for further improvement in order to provide a safe hydrogen storage at higher pressure, higher weight content of hydrogen, lower losses of hydrogen on storage as well as sufficient hydrogen load and release rates in operation, which will result in increased safety and cost-saving.

According to one general aspect, the present invention partially eliminates disadvantages of the prior art techniques and provides a novel apparatus for storage of compressed hydrogen gas including one or more novel cartridges containing hydrogen gas, a hydrogen liberating tool, and a control system configured for controlling operation of the apparatus. Specifically, the apparatus comprises a sealed housing having an outlet pipe coupled to the housing and equipped with a controllable discharge valve. The sealed housing defines a chamber that includes the cartridge comprising a plurality of cylindrical voids containing said compressed hydrogen gas. According to the invention, the cartridge can be either expendable (i.e., disposable) or rechargeable. The hydrogen liberating tool is configured for controllable liberating the hydrogen gas from the cartridge into a volume of the chamber that is not occupied by the cartridge. The control system is operatively coupled to the controllable discharge valve and the hydrogen liberating tool, and configured for controlling operation thereof. The housing can include a detachable cover adapted to open and seal the housing.

According to the invention, the pressure of the hydrogen stored within the cylindrical voids can be higher than 1000 ami. In turn, the pressure of the hydrogen accumulated within the volume of the chamber that is not occupied by the cartridge is in the range of 1 atm to 10 arm. According to an embodiment of the invention, the control system includes a pressure sensor configured for producing a pressure sensor signal representative of the hydrogen gas pressure in the chamber. Moreover, the control system includes a flow meter configured for producing a gas flow sensor signal representative of the flow of the hydrogen gas pressure in the outlet pipe. The control system also includes a controller operatively coupled to the pressure sensor and the flow meter. Accordingly, the control system is responsive to the pressure sensor signal and the gas flow sensor signal. Thus, the controller is capable of generating control signals for controlling the operation of the hydrogen liberating tool and the discharge valve.

The apparatus can further include at least one safety valve that can be automatically open when pressure in the chamber reaches a dangerous level.

According to one embodiment of the invention, the cartridge includes a case and an assembly structure formed of plurality of closely packed hollow microcylinders arranged in the case. The microcylinders have sealed ends, thereby they define the aforementioned cylindrical voids. According to this embodiment, the microcylinders are made of material having relatively small hydrogen permeability at the temperatures below 60⁰C and more than 10 times higher permeability at the temperatures above 200⁰C. A ratio of the tensile strength to the density of the material of the microcylinders can be greater than 1700 MPa-cm³/g. The external diameter of the microcylinders can be in the range of 1 micrometer to 5000 micrometers. In turn, a ratio of the wall thickness to the external diameter of the microcylinders can be in the range of 0.01 to 0.2. The external diameter of the microcylinders can be reduced from a center of the assembly structure towards edges of the structure. Likewise, the wall thickness of the microcylinders can be increased from the center of the assembly structure towards the edges of the structure. Thickness of the case wall can be at least 10 times greater than the thickness of the microcylinder walls.

According to this embodiment of the invention, the hydrogen liberating tool includes an electrically heating element arranged within the cartridge, and a controllable power source coupled to the control system and configured for controllable powering the electrically heating element, whereby to controllably vary a temperature of the microcylinders. The neighboring microcylinders can abut on one another at their walls, thereby forming empty inter-cylinder spaces along the microcylinders. For example, the electrically heating element can include a wire woven throughout the assembly structure of the plurality of closely packed hollow microcylinders such that folded segments of the wire are located in said inter-cylinder spaces. This allows a controllable changing of the temperature of the microcylinders and provides a controllable liberating of the hydrogen stored within the microcylinders into the inter-cylinder spaces and the other volume of the case that is not occupied by the microcylinders.

The cartridge can be equipped with at least one temperature sensor arranged in the inter-cylinder spaces. The temperature sensor can be configured for measuring temperature of the microcylinders and producing a temperature sensor signal indicative of the temperature. The control system is coupled to the temperature sensor and responsive to the temperature sensor signal for providing control of the electrically heating element, thereby to avoid overheating and damage of the cartridge.

According to another embodiment of the invention, the cartridge includes a monolithic block having a plurality of cylindrical cavities formed therein. Ends of the cylindrical cavities distal to the hydrogen liberating tool are sealed, whereas opposite ends of the cylindrical cavities (proximate to the hydrogen liberating tool) are covered with a hydrogen diffuser plate. Thus, according to this embodiment, the cylindrical cavities define the aforementioned cylindrical voids. For example, the hydrogen diffuser plate can be made of a material characterized by photo-enhanced hydrogen diffusion. Specifically, the hydrogen diffuser plate can include a highly permeable to hydrogen substrate covered by a layer made of the material characterized by photo-enhanced hydrogen diffusion.

According to this embodiment, the hydrogen liberating tool includes a controllable radiation source operating in a predetermined radiation frequency range. The controllable radiation source is coupled to the control system adapted to control the operation of the radiation source, thereby providing photo-enhanced diffusion of hydrogen through the hydrogen diffuser plate when it is illuminated by said controllable radiation source.

For example, the control of the operation of the radiation source can be carried out by varying the intensity of the applied radiation. According to another example, the control of the operation of the radiation source can be carried out by turning the source on and off with a predetermined periodicity. According to an embodiment of the invention, the hydrogen diffuser plate includes a layer of impermeable to hydrogen dielectric material perforated with a plurality of small holes plugged with stoppers that seal the holes. The density of the holes is such that at least one sealed opening is formed for each cylindrical cavity. According to this embodiment, a coefficient of thermal expansion of the layer is higher than the coefficient of thermal expansion of the stoppers. The hydrogen liberating tool includes an electrically heating element. For example, the hydrogen liberating tool can include a heating layer made of conductive permeable to hydrogen material placed on the hydrogen diffuser plate and coupled to the controllable power source.

According to a further embodiment of the invention, the cartridge includes an assembly structure formed of plurality of bound hollow microcylinders having both microcylinder ends sealed. In this case, the hydrogen liberating tool can include an electric drive arranged in the housing. For providing liberation of the hydrogen gas, hydrogen liberating tool includes an opener mounted on a shaft of the electric drive and configured for gradual destroying the microcylinder ends proximal to the liberating tool. Preferably, a direction of the shaft coincides with the direction of the cylinders, whereas the direction of the knife's blade is perpendicular to the direction of the shaft. The electric drive includes an electric motor operatively coupled to the control system for providing controllable rotation of the shaft. When required, the apparatus and the control system can also be configured for providing controllable longitudinal motion of the shaft. For example, all the microcylinder ends proximal to the liberating tool can be destroyed during one total revolution of the shaft.

According to yet an embodiment of the invention, the cartridge includes a monolithic block having a plurality of cylindrical cavities formed therein having sealed ends and filled with hydrogen gas. In this case, the hydrogen liberating tool can include an electric drive arranged in the housing, and an opener mounted on a shaft of the electric drive. The opener is configured for gradual destroying the ends of the cavities proximal to the said hydrogen liberating tool, thereby providing liberation of the hydrogen gas gradually. Accordingly, the electric drive can include an electric motor operatively coupled to the control system for providing controllable rotation of the shaft. Likewise, when required, the apparatus and the control system can also be configured for providing controllable longitudinal motion of the shaft. The apparatus according to the present invention is of durable and reliable construction. Moreover, the apparatus according to the present invention may have a low manufacturing cost.

According to another general aspect of the invention, there is provided a system for filling a cartridge having a plurality of cylindrical voids adapted for storing hydrogen gas. The system includes an autoclave having a housing defining a chamber configured for holding the cartridge. The system also includes an activation tool configured for operating an activation element providing hydrogen gas penetration into the cylindrical voids.

The system can include a controllable vacuum pump communicating with the chamber of the autoclave through a manifold equipped with a pump valve. For example, the controllable vacuum pump can be a roughing-down pump adapted to vacuumize the chamber up to the pressure of about 10^"3 - 10^~2 torrs.

The system can also include a controllable evacuating unit that communicates with the chamber of the autoclave through the manifold equipped with an evacuation valve. The system can also include a controllable blowing unit communicating with the chamber through manifold equipped with a blower valve and configured for blowing cooled hydrogen gas through the chamber. The system also includes a controllable compressing unit communicating with the chamber through the manifold coupled to a vessel containing pure hydrogen gas used for the filling of the cartridge, and equipped with a compressor valve. The system also includes a control unit coupled to at least one device selected from the activation element, the pump valve, the vacuum pump, the evacuating unit, the blowing unit, the compressing unit, the evacuation valve, the blower valve, the compressor valve, and configured for controlling operation thereof.

The housing is made of material that is capable to withstand the pressure values exceeding the pressure of the hydrogen gas maintained in said cylindrical voids of the cartridge after the filling. According to still another embodiment of the invention, the cartridge includes a case and an assembly structure formed of plurality of closely packed hollow microcylinders arranged in the case. The microcylinders have sealed ends, thereby defining the aforementioned cylindrical voids. In this case, the activation element includes a controllable electrically heating element arranged within the cartridge. For example, the electrically heating element can include an electrically conductive wire woven throughout the assembly structure of the microcylinders such that folded segments of the wire are located in inter-cylinder spaces.

According to another embodiment of the invention, the cartridge includes a monolithic block having a plurality of cylindrical cavities formed therein. Ends of the cylindrical cavities distal to the activation tool are sealed, whereas opposite ends of the cylindrical cavities proximate to the activation tool are covered with a hydrogen diffuser plate, thereby defining the aforementioned cylindrical voids. For example, the activation element can include a controllable radiation source configured to provide photo- enhanced diffusion of hydrogen through the hydrogen diffuser plate when the plate is illuminated by radiation of a predetermined frequency range. According to another example, the activation element can include a heating layer made of conductive permeable to hydrogen material placed on the hydrogen diffuser plate.

The system can also comprise a pressure sensor operable for producing a gas pressure sensor signal indicative of the pressure in the chamber. The pressure sensor is coupled to the control unit which is responsive to the gas pressure sensor signal and capable of generating a control signal to at least one aforementioned system component for controlling thereof.

The system can also comprise a temperature sensor operable for producing a gas temperature sensor signal indicative of the temperature within the chamber. The temperature sensor is coupled to the control unit which is responsive to the temperature sensor signals and capable of generating a control signal to aforementioned system component for controlling thereof. According to yet another general aspect of the invention, there is provided a method of filling a cartridge having a plurality of cylindrical voids adapted for storing hydrogen gas. The method comprises placing the cartridge into a chamber; vacuumizing the chamber to a predetermined pressure; preparing the cartridge in order to let the hydrogen gas diffuse into the cylindrical voids; and controlled compressing the hydrogen gas in the chamber over a predetermined compression time interval while maintaining the step of preparing the cartridge operating until the pressure in the chamber reaches a predetermined pressure value, thereby providing the hydrogen gas diffusion into the cylindrical voids. The predetermined pressure value is up to about 3000 atm. The predetermined compression time interval is in the range of several minutes to several hours.

According to an embodiment of the invention, the cartridge includes a case and an assembly structure formed of plurality of closely packed hollow microcylinders arranged in the case. The microcylinders have sealed ends, thereby defining the aforementioned cylindrical voids. In this case, the step of preparing of the cartridge includes heating the microcylinders to a predetermined temperature. The predetermined temperature can be in the range of about 300⁰C- 500⁰C.

According to another embodiment of the invention, the cartridge includes a monolithic block having a plurality of cylindrical cavities formed therein. The cylindrical cavities are sealed at one end and covered with a hydrogen diffuser plate at another end. In this case, the step of preparing of the cartridge includes illuminating said hydrogen diffuser plate by radiation of a predetermined frequency range, thereby to provide photo-enhanced diffusion of hydrogen therethrough. When required, the step of preparing of the cartridge can include heating the hydrogen diffuser plate to a predetermined temperature.

According to an embodiment of the invention, the method can further comprise the steps of terminating the preparing of the cartridge, and the controlled hydrogen gas compressing; depressurizing the chamber; and blowing cooled hydrogen gas through the chamber. According to an embodiment of the invention, the method can further comprise the steps of: terminating the preparing of the cartridge, while maintaining the hydrogen gas compressing step to operate, thereby to keep the pressure in the chamber at the maximal value over the time interval until the cartridge is returned to the condition of small hydrogen permeability; and depressurizing the chamber.

There has thus been outlined, rather broadly, the more important features of the invention so that the detailed description thereof that follows hereinafter may be better understood, and the present contribution to the art may be better appreciated. Additional details and advantages of the invention will be set forth in the detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS hi order to understand the invention and to see how it may be carried out in practice, preferred embodiments will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which:

Fig. 1 is a schematic cross-sectional view of an apparatus for storage of hydrogen gas is illustrated;

Fig. 2A is a cross-sectional schematic view of the apparatus of Fig. 1 including a hydrogen storage cartridge and a hydrogen liberating tool, according to one embodiment of the present invention;

Fig. 2B is a top cross-sectional schematic view of the apparatus of Fig. 2A taken along the line A-A therein;

Fig. 3 A is a schematic view of the apparatus of Fig. 1 having the hydrogen storage cartridge and the hydrogen liberating tool according to another embodiment of the present invention;

Fig. 3B is a top cross-sectional schematic view of the apparatus of Fig. 3A taken along the line B-B therein;

Fig. 4 is schematic view of the apparatus of Fig. 1 having the hydrogen storage cartridge and the hydrogen liberating tool according to still another embodiment of the present invention;

Fig. 5 shows schematically an example of a perforated layer of the hydrogen diffuser plate, according to this embodiment of the invention;

Fig. 6 is a schematic view of me apparatus of Fig. 1 having the hydrogen storage cartridge and the hydrogen liberating tool according to yet another embodiment of the present invention; Fig. 7 is a schematic cross-sectional view of a system for filling the cartridge of the present invention with hydrogen gas;

Fig. 8 shows an exemplary packaging of an assembly of microcylinders in the hydrogen storage cartridge; and Fig. 9 shows an exemplary group of microcylinders having a hexagonal cross- section shape.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

The principles and operation of an apparatus for storage hydrogen gas according to the present invention may be better understood with reference to the drawings and the accompanying description. It should be understood that these drawings are given for illustrative purposes only and are not meant to be limiting. It should be noted that the figures illustrating various examples of the apparatus of the present invention are not to scale, and are not in proportion, for purposes of clarity. It should be noted that the blocks as well other elements in these figures are intended as functional entities only, such that the functional relationships between the entities are shown, rather than any physical connections and/or physical relationships. The same reference numerals and alphabetic characters will be utilized for identifying those components which are common in the hydrogen storage apparatus and its components shown in the drawings throughout the present description of the invention.

Referring to Fig. I₅ a schematic cross-sectional view of an apparatus 10 for storage of hydrogen gas is illustrated, according to one embodiment of the present invention. The hydrogen storage apparatus 10 comprises a housing 11 having a detachable cover 12 adapted to open and seal the housing 11. The sealed housing 11 defines a chamber 13 that includes a cartridge (module) 14 mounted in the chamber 13 with the help of fasteners (not shown). The cartridge 14 includes a plurality of cylindrical voids (not shown in Fig. 1) containing compressed hydrogen gas. Various ways of organization of the cylindrical voids in the cartridge 14 will be described hereinbelow. The cartridge 14 can be either expendable or rechargeable. The cartridge 14 can be inserted into the chamber 13 and removed therefrom through an opening (not shown) that is sealed by the detachable cover 12. The apparatus 10 also includes a hydrogen liberating tool diagrammatically represented by a box 15, and a control system 16 operatively coupled to the hydrogen liberating tool 15 and configured for controlling operation thereof. The hydrogen liberating tool 15 is configured for controllable liberating hydrogen gas from the cartridge 14 in which the hydrogen is stored at very high pressures into a volume of the chamber 13 that is not occupied by the cartridge 14 and in which the hydrogen is stored at a moderate pressure. For example, the pressure of the hydrogen stored within the cartridge 14 can be higher than 1000 atm (e.g., in the range of 1000 atm - 3000 atm), whereas the pressure of the hydrogen within the unoccupied volume of the chamber 13 can be in the range of 1 atm- 10 atm.

For measuring pressure of the hydrogen within the unoccupied volume of the chamber 13 the control system 16 includes a pressure sensor 161 that is operable for producing a gas pressure sensor signal. The pressure sensor 161 is coupled to a controller 162 of the control system 16 which is, inter alia, responsive to the gas pressure sensor signal and capable of generating a control signal to the hydrogen liberating tool 15 for controllable liberation of the compressed hydrogen gas from the cartridge 14.

Shape of the housing 11 can, for example, be tubular. However, it should be understood that generally, any desired shape of the housing 11 can be used. The housing 11 can be constructed of a suitable metal, plastic or composite material with thickness of the walls appropriate to withstand the strain on the walls caused by the gas pressure inside the housing 11.

The apparatus 10 also includes an outlet pipe 17 coupled to the housing 11. The control system 16 also includes a flow meter 163 and a discharge valve 164 arranged in the outlet pipe 17 and coupled to the controller 162 for controllable discharge of the gaseous hydrogen from the chamber 13. In operation, the flow of the hydrogen gas within the outlet pipe 17 is measured by the flow meter 163 that is operable for producing a gas flow sensor signal. The flow meter 163 is coupled to the controller 162 which is, inter alia, responsive to the gas flow sensor signal and capable of generating a valve control signal for controlling the operation of the discharge valve 164. The hydrogen discharged thereby can be used as a fuel or as a raw material in reactions desired by a user. The apparatus 10 can also include one or several safety valves 18 that can automatically open when pressure in the chamber 13 reaches a dangerous level.

According to the invention, the structure of the hydrogen storage cartridge 14 and the hydrogen liberating tool 15 can have various configurations. Referring to Figs. 2A and 2B, a schematic view of the apparatus of Fig. 1 in which the rechargeable cartridge 14 for hydrogen storage and the hydrogen liberating tool 15 are illustrated according to one embodiment of the present invention. According to this embodiment, the cartridge 14 includes a case 141 and an assembly structure 142 of micro-containers located in the case 141. According to this embodiment of the invention, the assembly structure 142 of the micro-containers includes a plurality of closely packed hollow microcylinders (microtubes) 21. Ends 22a and 22b of the microcylinders 21 are sealed, e.g., capped on the ends by semi-spheres with comparable wall thickness, thereby defining the voids in which the compressed hydrogen gas is contained. The hollow microcylinders 21 themselves or at least one of the sealed ends 22a and 22b are made of a material that is at least partially permeable to hydrogen, to allow hydrogen molecules to diffuse therethrough. Preferably, the hollow microcylinders 21 are made of material having relatively small hydrogen permeability at temperatures below 60⁰C and high permeability (more than 10 times higher) at temperatures above 200⁰C. Preferably, the materials having high tensile strength σ at low density p are selected for the microcylinders 21. For example, the materials that meet the condition σ/p ≥ 1700 MPa-cm³/g are suitable for the microcylinders 21. Examples of the materials suitable for the microcylinders 21 include, but are not limited to, MgAlSi glasses (e.g., S-2 Glass , R glass available from Saint-Gobain Vetrotex Textiles, T Glass available from Nitto Boseki Co., Ltd. (Nittobo)), fused quartz, polymers (e.g., Kevlar , Twaron ), etc.

Generally, the hollow microcylinders 21 can have any desired length. In turn, the external diameter d of the microcylinders 21 can be in the range of about 1 micrometer to 1 millimeter. Magnitudes of wall thickness h of the microcylinders 21 are defined by the value of the ratio h/d, that can be obtained from the equation h/d=p/(2σ), where p is the pressure of the hydrogen stored in the microcylinders 21 and σ is the tensile strength of the microcylinder material. Preferably, the ratio of the wall thickness to the external diameter is in the range of 0.01 to 0.2, depending on^» andσ. It should be noted that the external diameter d and wall thickness h of the microcylinders located in the inner layers (i.e., in the bulk) of the assembly structure 142 and the peripheral microcylinders can be different, hi particular, the external diameter of the microcylinders 21 can be reduced from a center of the assembly structure towards edges of the structure. By placing larger microcylinders inside the structure and smaller microcylinders towards the edges, a hydrogen accumulation and storage structure is created in which the wall tensions decreasing towards the circumference due to lower diameter of the microcylinders. Accordingly, the wall thickness h of the microcylinders can be increased from the center of the assembly structure towards the edges of the structure.

Methods for fabrication of spaced apart hollow microcylinders for hydrogen storage are known per se (see, for example, a paper by Yan K.L. et al published in Int. J. Hydrogen Energy, V. 10, N. 7/8, PP. 517-522, 1985), and therefore will not be expounded hereinbelow. According to the embodiment shown in Figs. 2A and 2B, the assembly 142 of the microcylinders 21 is enveloped by the case 141. The inner surface of the case wall can be bound to the peripheral microcylinders of the assembly 142. Generally, the case 141 can be constructed of any suitable metal, plastic or composite material, and be of any desired shape and configuration having rigidity sufficient for manipulation of the cartridge for its insertion into and removing from the housing 11. Preferably, the case 141 and the microcylinders 21 are made of the same material. Thickness of the case wall can be 10-12 times greater than the thickness of the microcylinder walls. As shown in Figs 2A and 2B, the case 141 can have cylindrical shape, i.e., replicate the shape of the inner surface of the housing 11. Generally, the case 141 can have any desired shape. When required, the case 141 can be equipped with a carry handle 143 arranged to facilitate a user to insert, remove and/or carry the cartridge 14.

According to an embodiment of the invention, the microcylinders 21 in the assembly structure 142 are circular in their cross-section and closely (intimately) packed in the case 141, but they are not bound together. According to another embodiment of the invention, the microcylinders 21 are bound together to form a rigid structure, hi this case, the microcylinders 21 can have any arbitrary form in their cross-section, e.g. hexagonal (see Fig. 8). When the microcylinders are made of glass, aramid or metal, they can be bound together, for example, by sintering. Likewise, an adhesive material, such as glue, can also be used for binding the microcylinders.

When the microcylinders 21 are assembled together in the assembly structure 142, the neighboring microcylinders abut on one another at their walls forming empty inter-cylinder spaces 144 along the microcylinders. According to an embodiment of the invention, the hydrogen liberating tool 15 includes an activation element, such as an electrically heating element 145 arranged within the cartridge 14 for activation of liberation (diffusion release) of the hydrogen gas stored within the microcylinders 21. The electrically heating element 145 is powered by a controllable power source 151 arranged outside of the housing 11 and coupled to the control system 16. In operation, depending on the pressure of the hydrogen gas within the chamber 13 measured by the pressure sensor 19, the control system is, inter alia, adapted to control the operation of the power source 151. Thus, the electrically heating element 145 powered by the controllable power source 151 can controllably vary the temperature within the cartridge 14, thereby providing a controllable liberating of the hydrogen stored within the microcylinders 21 into the inter-cylinder spaces 144 and the other volume of the case 141 that is not occupied by the microcylinders 21. The hydrogen gas accumulated in the cartridge 14 will further diffuse through the case 141 into the volume of the chamber 13 that is not occupied by the cartridge 14.

According to the embodiment of the invention shown in Figs 2A and 2B, the electrically heating element 145 includes a wire 146 woven throughout the assembly structure 142 such that folded segments 147 of the wire are located in the inter-cylinder spaces 144. For example, the wire segments 147 can be connected in series and represent one circuit. Alternatively, the wire segments 147 can be grouped in several circuits.

It should be understood that the microcylinders 21 can be arranged (bundled) in groups. Each group can include more than 2 microcylinders and have any desired cross- section shape, e.g. circular, oval, polygonal, etc. Preferably, the cross-section shape of each group is hexagonal (see Fig. 9), to provide the possibility of the closest packing of the groups. In such a case, the folded segments 147 of the wire can be located in the interphase between the neighboring groups. When electric voltage is applied across the circuit(s), electric current passing therethrough is produced for heating the wire segments and consequently the microcylinders 21. Ends 148 of the wire 146 are brought out to one part of a connector 149 arranged at the outer side of the case 141. Another part of the connector 149 can be arranged within the housing 11 and coupled to the power source 151. Thus, the connector 149 connects the wire 146 to the controllable power source 151. The controllable power source 151 can be controlled in such a manner that the voltage applied across the circuit or number of the circuits powered by the power source 151 is increased when the pressure in the chamber 13 is lower than the required level, and vice versa, the voltage applied across the circuit or number of the circuits powered by the power source 151 is decreased when the pressure in the chamber 13 is higher than the required level.

When required to control temperature during the heating of the microcylinders 21, the cartridge 14 can be equipped with one or several temperature sensors 152 arranged in the inter-cylinder spaces 144, and configured for measuring temperature of the microcylinders 21 and producing a temperature sensor signal indicative of the temperature. The temperature sensors 152 are coupled to the control system 16 which is, inter alia, responsive to the temperature sensor signal and capable of providing a control of the electrically heating element 145 to avoid overheating and damage of the cartridge elements.

Referring to Figs. 3A and 3B, a schematic view of the apparatus of Fig. 1 in which the rechargeable cartridge 14 for hydrogen storage and the hydrogen liberating tool 15 are illustrated according to another embodiment of the present invention. According to this embodiment, the cartridge 14 includes a monolithic block 31 having a plurality of cylindrical cavities 32 formed therein. The material of the monolithic block 31 is impermeable to hydrogen. Ends 33 of the cylindrical cavities 32 distal to the hydrogen liberating tool 15 are sealed. Ends 34 of the cylindrical cavities 32 proximate to the hydrogen liberating tool 15 are covered with a hydrogen diffuser plate 35. Thus, the cylindrical cavities 32 (sealed from the two ends) form the cylindrical voids of the invention in which hydrogen gas can be stored at very high pressure.

According to this embodiment of the invention, the hydrogen diffuser plate 35 features photo-enhanced hydrogen diffusion characteristics. According to one example, the hydrogen diffuser plate 35 is made of a material characterized by photo-enhanced hydrogen diffusion. According to another example, the hydrogen diffuser plate 35 includes a highly permeable to hydrogen substrate covered by a layer made of the material characterized by photo-enhanced hydrogen diffusion. The materials that demonstrate great acceleration of the release rate of hydrogen through the hydrogen diffuser plate 35 owing the infrared (IR) radiation are known in the art (see, for example, a paper titled "Photo-Enhanced Hydrogen Outgassing of Glass," by D. B. Rapp and J. E. Shelby, published in J. Non-Cryst. Solids, 2004, V. 349, PP. 254-259). For example, doping commercially available borosilicate glasses with optically active elements (e.g., Fe₃O₄) can result in a drastic sensitivity of the rate of hydrogen diffusion to IR radiation.

According to this embodiment of the invention, the hydrogen liberating tool 15 includes an activation element, such as a controllable radiation source 36 providing photo-enhanced diffusion of hydrogen through the hydrogen diffuser plate 35 when the plate 35 is illuminated by the radiation of the predetermined frequency range. Depending on the material of the hydrogen diffuser plate 35 the controllable radiation source 36 can operate in various ranges of the electromagnetic scale.

For example, when the hydrogen diffuser plate 35 is based on the Pyrex™ glass doped with Fe₃O₄ the controllable radiation source 36 can be an infrared (IR) lamp. In effect, the IR radiation causes the dopant to react, opening up the microscopic pores that occur naturally in the glass. The hydrogen, which is under high pressure inside the voids formed of the sealed cylindrical cavities 32, can diffuse through the pores opened in the hydrogen diffuser plate 35. In this case the release of the hydrogen from the cylindrical voids can be controlled by varying the intensity of the IR radiation and/or by simply turning the IR source on and off.

To this end, the radiation source 36 is controlled by the control system 16. In operation, depending on the pressure of the hydrogen gas within the chamber 13, the control system is, inter alia, adapted to control the operation of the radiation source 36 by varying the intensity of the applied radiation and/or by turning the source on and off with a predetermined periodicity, thereby providing a controllable liberating of the hydrogen stored within the cylindrical cavities 32 into the volume of the chamber 13 that is not occupied by the cartridge 14. For example, when the pressure in the chamber is low, the intensity of the radiation can be increased, and vice versa.

Referring to Fig. 4, a schematic view of the apparatus of Fig. 1 in which the hydrogen storage cartridge 14 and the hydrogen liberating tool 15 are illustrated according to still another embodiment of the present invention. According to this embodiment, the cartridge differs from the cartridge shown in Fig. 3A in the construction of the hydrogen diffuser plate that is indicated in Fig. 4 by a reference numeral 41. The hydrogen diffuser plate 41 includes a layer 42 of impermeable to hydrogen dielectric material perforated with a plurality of small holes 43. Fig. 5 shows schematically an example of the layer 42 of the hydrogen diffuser plate 41, according to this embodiment of the invention. The density of the holes 43 is such that at least one opening must be formed for each cylindrical cavity (32 in Fig. 4) when the hydrogen diffuser plate is bound to the ends 34 of the cylindrical cavities 32. The holes 43 are plugged with matched stoppers 44 that seal the cylindrical cavities 32. The sealed cylindrical cavities 32 form the cylindrical voids of the invention in which hydrogen gas can be stored at very high pressure.

According to this embodiment of the invention, the materials selected for the layer 42 and the stoppers 44 feature different coefficients of thermal expansion. Specifically, the coefficient of thermal expansion of the layers 42 is higher than the coefficient of thermal expansion of the stoppers 44. Examples of the materials suitable for the layer 42 include, but are not limited to, borosilicate glass, quartz and some metals. Examples of the materials suitable for the stoppers 44 include, but are not limited to, glasses of the titanium-silica family, anisotropic Invar Fe-Ni alloys and ZrW₂O₃, which have negative linear thermal expansion coefficient along the specific axis. Such a construction of the holes and stoppers inside the holes forms thermophysical microvalves that can operate as follows. When the hydrogen diffuser plate is heated, the mismatch of the thermal expansion coefficients will result in the formation of the gap 46 between an inner surface of the holes 43 and edges of the stoppers 44. For example, when the holes and the stoppers have a circular shape, an annular gap is formed.

It should be noted that generally the shape of the holes 43 and stoppers 44 is not bound by the circular shape. Examples of the suitable shapes include, but are not limited to, rectangular shape, polygonal shape, elliptical shape, etc.

According to this embodiment of the invention, the hydrogen liberating tool 15 includes an activation element, such as an electrically heating element 45 arranged in the proximity to the hydrogen diffuser plate 41. For example, as shown in Fig. 4, the electrically heating element 45 can include a heating layer 451 made of conductive permeable to hydrogen material that is placed on the hydrogen diffuser plate 41 and coupled to the controllable power source 151. Examples of the materials suitable for the heating layer 451 include, but are not limited to, porous graphite or Pd-Ni alloys.

The electrically heating element 45 is powered by the controllable power source 151 arranged outside of the housing 11 and coupled to the control system 16. In operation, depending on the pressure of the hydrogen gas within the chamber 13 measured by the pressure sensor 19, the control system is, inter alia, adapted to control the operation of the power source 151. Thus, the electrically heating element 45 powered by the controllable power source 151 can controllably vary the temperature of the hydrogen diffuser plate 41. Specifically, when electric voltage produced by the power source 151 is applied across the heating layer 451, electric current passing therethrough is produced that generates heat for heating the hydrogen diffuser plate 41 arranged under the heating layer 451. As a result of the mismatch of the thermal expansion coefficients of the holes 43 and the stoppers 44, a gap 46 therebetween is formed; thereby providing a controllable liberating of the hydrogen gas stored within the sealed cylindrical cavities 32 into the volume of the chamber 13 that is not occupied by the cartridge 14. Accordingly, when the voltage supplied by the power source 151 is decreased or switched off, the hydrogen diffuser plate 41 will be cooled and the gap between the holes 43 and stoppers 44 will be eliminated; thereby decreasing or ceasing the liberation of the hydrogen gas.

For release of hydrogen from the cartridge 14 it is also possible to use methods other than diffusion methods described above. For example, the micro-containers formed of a plurality of closely packed microcylinders and/or the cylindrical cavities in the monolithic block described above can be sealed. In particular, the microcylinders can be closed by caps, for example, after being filled with hydrogen inside a high- pressure chamber, e.g., by applying melting temperature to the ends. Hydrogen release can be organized by one-by-one destroying of the caps, mechanically or by other means. Referring to Fig. 6, a schematic view of the apparatus of Fig. 1 in which the hydrogen storage cartridge 14 and the hydrogen liberating tool 15 are illustrated, according to yet another embodiment of the present invention.

According to one example, the cartridge 14 can include a monolithic block 31 having a plurality of cylindrical cavities (such as voids) 32 formed therein. The material of the monolithic block 31 can be impermeable to hydrogen. The ends 33 and 34 of the cylindrical cavities 32 can be sealed. Preferably, the ends 34 of the cylindrical cavities

32 proximate to the hydrogen liberating tool 15 are protruded from monolithic block 31.

According to another example, the cartridge 14 can include a plurality of hollow microcylinders having sealed ends, which are bound in an assembly structure and charged with the hydrogen gas. In particular, the microcylinders can be tied with a fastener, e.g., girded with a fastening band. Alternatively, the microcylinders can be welded together. Preferably, the ends of the cylindrical cavities proximate to the hydrogen liberating tool are protruded from the assembly structure. These examples of the cartridges 14 provide expendable cartridges that may be easily replaced in the housing 11 when spent.

According to the embodiment shown in Fig. 6, the hydrogen liberating tool 15 includes an activation element, such as an electric drive 153 arranged in the housing 11 and an opener (e.g., knife) 154 mounted on a shaft 155 of the electric drive 153. Preferably, a direction of the shaft 155 coincides with the direction of the cylinders (or cylindrical cavities), whereas the direction of the knife's blade is perpendicular to the direction of the shaft 155.

The electric drive 154 includes an electric motor 156 that provides rotation of the shaft 155. Preferably, the electric motor 156 is mounted on the outer surface of the housing 11 at one of its ends. The electric motor 156 is operatively coupled to the control system 16. hi turn, the control system 16 is, inter alia, responsive to the gas pressure sensor signal generated by the pressure sensor 161, and is capable of generating a motor control signal to the electric motor 156 for control of angular velocity of rotation of the knife 154. It should be understood that if required by the configuration of the cylinders in the cartridge 14, the control system 16 can also control feed of knife 154 by providing longitudinal motion of the shaft 155. Hydrogen liberation can be organized in a gradual manner, e.g., by one-by-one cutting the ends 34 with the knife 154. The electric motor 156 can be controlled in such a manner that the velocity of rotation of the knife 154 is increased when the pressure in the chamber 13 is lower than the required level, and vice versa, the velocity is decreased when the pressure in the chamber 13 is higher than the required level. The electric drive 154 can be configured such that during the total destruction of the ends 34, the shaft maintains one total revolution.

According to another general aspect of the present invention, there is provided a method of filling the cartridge 14 with hydrogen gas. Depending on the cartridge configuration, hydrogen filling into the cylindrical voids occurs by permeation (diffusion) through walls of the microcylinders (21 in Fig. 2A) or through the hydrogen diffuser plate (35 in Fig. 3A). In general, the overall rate of hydrogen transport through the wall/plate depends on the temperature, the thickness of the wall or diffuser plate, the pressure difference and the exchange surface area available.

Referring to Fig. 7, a schematic cross-sectional view of a system 70 for filling the cartridge 14 with hydrogen is illustrated, according to an embodiment of the present invention. The system 70 includes an autoclave 71 having a housing 711 made of material that is capable to withstand very high pressure, hi particular, the housing 711 should be capable of withstanding the pressure values exceeding the pressure of the hydrogen gas maintained in the cylindrical voids of the cartridge after the filling. Examples of the materials suitable for the housing 711 include, but are not limited to, composite materials containing carbon, quartz and/or aramid filaments. The housing 711 defines a chamber 712 configured for holding the cartridge 14 that is inserted therein for filling with hydrogen. After the insertion, the housing 711 is sealed, for example, by means of a cover 713 that covers an opening (not shown) at one of the housing ends through which the cartridge is inserted.

The autoclave 71 also includes an activation tool 714 configured for operating activation elements (not shown) that provide the hydrogen gas to penetrate into the cylindrical voids of the cartridge. The arrangement and configuration of the activation elements are determined by the type of the cartridge 14. Specifically, for the embodiment of the apparatus utilizing the cartridge 14 shown in Figs. 2A and IB, the activation element can include the controllable electrically heating element arranged within the cartridge. The electrically heating element can be powered by a controllable power source (not shown) arranged outside of the autoclave 71. As described above with the reference to Fig. 2A₅ the electrically heating element includes a wire woven throughout the assembly structure of the microcylinders 21 such that folded segments of the wire are located in the inter-cylinder spaces.

Accordingly, for the embodiment of the apparatus utilizing the cartridge 14 shown in Figs. 3A and 3B, the activation element can include the controllable radiation source that can provide photo-enhanced diffusion of hydrogen through the hydrogen diffuser plate (35 in Fig. 3A) when the plate 35 is illuminated by the radiation of the predetermined frequency range.

Likewise, for the embodiment of the apparatus utilizing the cartridge 14 shown in Fig. 4, the activation element can include the electrically heating element arranged in the proximity to the hydrogen diffuser plate (41 in Fig. 4). In this case, the electrically heating element can include a heating layer (451 in Fig. 4) made of conductive permeable to hydrogen material that is placed on the hydrogen diffuser plate 41 and coupled to the controllable power source (not shown).

In turn, for the embodiment of the apparatus utilizing the expandable cartridge shown in Fig. 6, the activation element can include the electrically heating element configured for controllable varying the temperature of the ends of either the cylindrical cavities proximate to the activation element or the plurality of hollow microcylinders. It should be understood that these ends can be sealed, e.g., capped by semi-spheres made of the material having relatively small hydrogen permeability at temperatures below 60⁰C and high permeability (more than 10 times higher) at temperatures above 200⁰C. In the latter case, when the cartridge includes the assembly structure of hollow microcylinders, the walls of the microcylinders as well can be made of such a material.

The system 70 also includes a controllable vacuum pump 72, e,g., a roughing- down pump, communicating with the chamber 712 of the autoclave 71 through a branch 731 of a manifold 73 equipped with a pump valve 721. The controllable vacuum pump 72 is configured to vacuumize (rough-down) the chamber 712 up to the pressure of about 10^"3 torrs - 10^'2 torrs.

The system 70 can also include a controllable evacuating unit 74 that communicates with the chamber 712 of the autoclave 71 through a branch 732 of the manifold 73 that is equipped with an evacuation valve 741. It should be noted that the evacuating unit 74 can include a buffer vessel (not shown) and operate under support of the controllable vacuum pump 72.

The system 70 further includes a controllable blowing unit 75 communicating with the chamber 712 through a branch 733 of the manifold 73 that is equipped with a blower valve 751. The controllable blowing unit 75 is configured for blowing cooled hydrogen gas through the chamber 713.

The system 70 further includes a controllable compressing unit 76 communicating with the chamber 712 through a branch 734 of the manifold 73 that is coupled to a vessel 77 containing pure hydrogen gas used for the filling of the cartridge 14, and equipped with a compressor valve 761. The controllable compressing unit 76 is configured for smooth or step changes of the pressure of the hydrogen gas fed into the chamber 712, in accordance with a predetermined algorithm determined by the type of the cartridge 14. The system 70 also includes a control unit 78 coupled to the activation element(s) of the activation tool 714, the vacuum pump 72, the evacuating unit 74, the blowing unit 75, the compressing unit 76, the valves 721, 741, 751 and 761, and configured for controlling the operation these elements of the system 70. It should be understood that when the activation element includes a heating element (see, for example, Figs. 2A and 4), the activation element can be coupled to the control unit 78 and the corresponding electric power source (not shown) through a connector 715 arranged in the housing 711 of the autoclave 71.

For measuring pressure of the hydrogen gas in the chamber 712, the system 70 includes a pressure sensor 781 that is operable for producing a gas pressure sensor signal indicative of the pressure in the chamber 712. The system 70 can also include a temperature sensor 782 that is operable for producing a gas temperature sensor signal indicative of the temperature within the chamber 712. The pressure sensor 781 and the temperature sensor 782 are coupled to the control unit 78 which is, inter alia, responsive to the gas pressure and temperature sensor signals and capable of generating control signals to all the controllable elements of the system for operating thereof. hi operation, the cartridge 14 to be filled with hydrogen is placed in the chamber 712 of the autoclave 71 that is then sealed with the cover 713. For the embodiments of the cartridge when the activation (heating) element is a part of the cartridge 14 (see, for example, Figs. 2A and 4), the parts of the connector 715 are inserted one inside the other, thereby providing the coupling of the activation element to the control unit 78 and the electric power source. Filling the cartridge 14 with high-pressure hydrogen gas can be a batch process that generally includes placing the cartridge into the chamber 712 of the autoclave 71; purging the chamber 712 in order to vacuumize it to a predetermined pressure; preparing the cartridge in order to let the hydrogen gas to diffuse into said cylindrical voids; and controlled compressing the hydrogen gas in the chamber over a predetermined compression time interval.

Specifically, the autoclave 71 is purged by vacuumizing (roughing-down) up to the pressure of about 10^"3 - 10^~2 torrs by the controllable vacuum pump 72 to remove air from the chamber 712 of the autoclave 71, thereby preparing the chamber to be fed with hydrogen gas. Then, the process of filling the cartridge 14 with hydrogen gas involves actuating the activating unit 714 over a required time interval that can include a predetermined period of preliminary preparation of the cartridge 14 to receive hydrogen, and then a predetermined compression period. Depending on the structure and configuration of the cartridge 14, the actuating of the activating unit 714 can include heating the microcylinders (21 in Fig. 2A) or the hydrogen diffuser plate (41 in Fig. 4). As a result, the cartridge 14 is heated to a temperature in the range of 300°G-500°C (depending on the material of the microcylinders), thereby preparing the cartridge 14 for letting the hydrogen gas to diffuse into the cylindrical voids. According to another embodiment, the actuating of the activating unit 714 can include a controllable operating of the radiation source (36 in Fig. 3A).

Afterwards, the process includes actuating the compressing unit 76 that provides pure hydrogen gas from the vessel 77 to the chamber 712. During the operation of the compressing unit 76 (in smooth or step regimes) over the compression time interval, the pressure in the chamber 712 increases. Because the activating unit 714 continues to operate, the cylindrical voids of the cartridge 14 can receive the hydrogen gas and the pressure in the cylindrical voids also increases. The autoclave is maintained under this regime until the hydrogen gas pressure in the autoclave reaches a predetermined pressure value. For example, the pressure in the autoclave can reach the value of about 3000 atm. The time needed to fill the cylindrical voids depends on many factors, such as the temperature level and the final filling pressure. The higher the required temperature and the higher the pressurization of the empty cylindrical voids, the longer the filling time. For example, the compression interval can be in the range of several minutes to several hours. The pressurization rate during filling procedure can be controlled such that the pressure difference between outer and inner cylindrical void pressure does not exceed the stress limit for the void to collapse.

After reaching the predetermined value of the pressure in the chamber 712, several further scenarios can be employed. Thus, according to one embodiment of the invention, the activating unit 714 and the compressing unit 76 can be both switched off, and the valve 761 is closed, hi turn, the chamber 712 is coupled to the evacuating unit 74 through the valve 741 for depressurization of the chamber 712. After the depressurization step, the valve 741 is closed and the chamber 712 is coupled to the controllable blowing unit 75 for blowing cooled hydrogen gas through the chamber 713. As a result of the cooling, the cartridge is cooled down and transformed in the regime of storing the hydrogen gas accumulated therein during the compression time interval. Thus, the filled cartridge can be removed from the autoclave 71 and utilized by a consumer. By maintaining the cartridge at relatively low ambient temperatures, e.g., at 24⁰C, the amount of hydrogen gas escaping from the cylindrical voids will be minimal, so that the gas can be stored within the cartridge during a long time period.

According to another embodiment of the invention, after the reaching of the predetermined value of the pressure in the chamber 712, the activating unit 714 is switched off, whereas the compressing unit 76 is still maintained operating, thereby to keep the pressure in the chamber at the maximal value over a certain time interval until the cartridge is returned to the condition of small hydrogen permeability. Specifically, the cartridge of the embodiments shown in Figs. 2A and 4 can be cooled down to the room temperature. It should be understood that this scenario prevents the release of hydrogen from the cartridge over the time interval when the activating unit 714 (facilitating diffusion of hydrogen into the cylindrical voids) is switched off. Then, the hydrogen pressure in the autoclave can be dropped, and the cartridge can be removed from the autoclave. As such, those skilled in the art to which the present invention pertains, can appreciate that while the present invention has been described in terms of preferred embodiments, the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures systems and processes for carrying out the several purposes of the present invention.

It is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.

It is important, therefore, that the scope of the invention is not construed as being limited by the illustrative embodiments set forth herein. Other variations are possible within the scope of the present invention as defined in the appended claims.

Claims

CLAIMS:

1. An apparatus for storage of compressed hydrogen gas, comprising: a sealed housing having an outlet pipe coupled to the housing and equipped with a controllable discharge valve, said sealed housing defines a chamber that includes a cartridge comprising a plurality of cylindrical voids containing said compressed hydrogen gas; a hydrogen liberating tool configured for controllable liberating the hydrogen gas from the cartridge into a volume of the chamber that is not occupied by the cartridge; and a control system operatively coupled to said controllable discharge valve and said hydrogen liberating tool, and configured for controlling operation thereof.

2. The apparatus of claim 1 wherein the housing further includes a detachable cover adapted to open and seal the housing.

3. The apparatus of claim 1 wherein said control system includes: a pressure sensor configured for producing a pressure sensor signal representative of the hydrogen gas pressure in the chamber, a flow meter configured for producing a gas flow sensor signal representative of the flow of the hydrogen gas pressure in the outlet pipe and a controller operatively coupled to said pressure sensor and said flow meter, and being responsive to said pressure sensor signal and said gas flow sensor signal, said controller being capable of generating control signals for controlling the operation of said hydrogen liberating tool and the discharge valve.

4. The apparatus of claim 1 further including at least one safety valve that can be automatically open when pressure in the chamber reaches a dangerous level.

5. The apparatus of claim 1 wherein said cartridge includes a case and an assembly structure formed of plurality of closely packed hollow microcylinders arranged in the case, the microcylinders having sealed ends, thereby defining said cylindrical voids.

6. The apparatus of claim 1 wherein the microcylinders are made of material having relatively small hydrogen permeability at the temperatures below 60⁰C and more than 10 times higher permeability at the temperatures above 200⁰C.

7. The apparatus of claim 5 wherein a ratio of the tensile strength to the density of the material of the microcylinders is greater than 1700 MPa-cm³/g.

8. The apparatus of claim 5 wherein the external diameter of the microcylinders is in the range of 1 micrometer to 5000 micrometers.

9. The apparatus of claim 8 wherein a ratio of the wall thickness to the external diameter of the microcylinders is in the range of 0.01 to 0.2.

10. The apparatus of claim 5 wherein the external diameter of the microcylinders is reduced from a center of the assembly structure towards edges of the structure.

11. The apparatus of claim 5 wherein the wall thickness of the microcylinders is increased from the center of the assembly structure towards the edges of the structure.

12. The apparatus of claim 5 wherein said hydrogen liberating tool includes an electrically heating element arranged within said cartridge; and a controllable power source coupled to the control system and configured for controllable powering said electrically heating element, whereby to controllably vary a temperature of the microcylinders.

13. The apparatus of claim 12 wherein neighboring microcylinders of said plurality of closely packed hollow microcylinders abut on one another at their walls, thereby forming empty inter-cylinder spaces along the microcylinders.

14. The apparatus of claim 13 wherein said electrically heating element includes a wire woven throughout said assembly structure of the plurality of closely packed hollow microcylinders such that folded segments of the wire are located in said inter-cylinder spaces, thereby to controllably vary the temperature of the microcylinders and provide a controllable liberation of the hydrogen stored within the microcylinders into the inter- cylinder spaces and the other volume of the case that is not occupied by the microcylinders.

15. The apparatus of claim 14 wherein said cartridge is equipped with at least one temperature sensor arranged in the inter-cylinder spaces, and configured for measuring temperature of the microcylinders and producing a temperature sensor signal indicative of the temperature, said control system being coupled to the temperature sensor and responsive to said temperature sensor signal for providing a control of the electrically heating element, thereby to avoid overheating and damage of the cartridge.

16. The apparatus of claim 5 wherein a thickness of the case wall is at least 10 times greater than the thickness of the microcylinder walls.

17. The apparatus of claim 1 wherein the cartridge includes a monolithic block having a plurality of cylindrical cavities formed therein, where ends of the cylindrical cavities distal to the hydrogen liberating tool are sealed, whereas opposite ends of the cylindrical cavities proximate to the hydrogen liberating tool are covered with a hydrogen diffuser plate, thereby defining said cylindrical voids.

18. The apparatus of claim 17 wherein said hydrogen diffuser plate is made of a material characterized by photo-enhanced hydrogen diffusion.

19. The apparatus of claim 17 wherein said hydrogen diffuser plate includes a highly permeable to hydrogen substrate covered by a layer made of the material characterized by photo-enhanced hydrogen diffusion.

20. The apparatus of claim 17 wherein the hydrogen liberating tool includes a controllable radiation source operating in a predetermined radiation frequency range, said controllable radiation source being coupled to the control system adapted to control the operation of the radiation source, thereby providing photo-enhanced diffusion of hydrogen through said hydrogen diffuser plate when it is illuminated by said controllable radiation source.

21. The apparatus of claim 17 wherein the control of the operation of the radiation source is carried out by varying the intensity of the applied radiation.

22. The apparatus of claim 17 wherein the control of the operation of the radiation source is carried out by turning the source on and off with a predetermined periodicity.

23. The apparatus of claim 17 wherein the hydrogen diffuser plate includes a layer of impermeable to hydrogen dielectric material perforated with a plurality of small holes plugged with stoppers that seal the holes, the density of the holes is such that at least one sealed opening is formed for each cylindrical cavity, where a coefficient of thermal expansion of the layer is higher than the coefficient of thermal expansion of the stoppers.

24. The apparatus of claim 23 wherein the hydrogen liberating tool includes an electrically heating element.

25. The apparatus of claim 24 wherein the hydrogen liberating tool includes a heating layer made of conductive permeable to hydrogen material placed on the hydrogen diffuser plate and coupled to the controllable power source.

26. The apparatus of claim 1 wherein said cartridge includes an assembly structure formed of plurality of bound hollow microcylinders having sealed ends and filled with the hydrogen gas; and wherein said hydrogen liberating tool includes an electric drive arranged in the housing, and an opener mounted on a shaft of the electric drive and configured for gradual destroying the microcylinders, thereby providing liberation of the hydrogen gas gradually.

27. The apparatus of claim 26 wherein a direction of the shaft coincides with the direction of the cylinders, whereas the direction of the knife's blade is perpendicular to the direction of the shaft.

28. The apparatus of claim 27 wherein said electric drive includes an electric motor operatively coupled to the control system for providing controllable rotation of the shaft.

29. The apparatus of claim 28 wherein said control system further configured for providing controllable longitudinal motion of the shaft.

30. The apparatus of claim 28 wherein all the microcylinders are destructed during one total revolution of the shaft.

31. The apparatus of claim 1 wherein said cartridge includes a monolithic block having a plurality of cylindrical cavities formed therein having sealed ends and filled with the hydrogen gas; and wherein said hydrogen liberating tool includes an electric drive arranged in the housing, and an opener mounted on a shaft of the electric drive and configured for gradual destroying the ends of the cavities proximal to the said hydrogen liberating tool, thereby providing liberation of the hydrogen gas gradually.

32. The apparatus of claim 31 wherein said electric drive includes an electric motor operatively coupled to the control system for providing controllable rotation of the shaft.

33. The apparatus of claim 32 wherein said control system further configured for providing controllable longitudinal motion of the shaft.

34. The apparatus of claim 32 wherein all the microcylinders are destructed during one total revolution of the shaft.

35. The apparatus of claim 1 wherein a pressure of the hydrogen stored within the cylindrical voids is higher than 1000 arm.

36. The apparatus of claim 1 wherein a pressure of the hydrogen accumulated within the within the volume of the chamber that is not occupied by the cartridge is in the range of 1 ami to lO atm.

37. A system for filling a cartridge having a plurality of cylindrical voids adapted for storing hydrogen gas, the system comprising: an autoclave having a housing defining a chamber configured for holding said cartridge; an activation tool configured for operating an activation element providing hydrogen gas penetrate into said cylindrical voids; a controllable vacuum pump communicating with the chamber of the autoclave through a manifold equipped with a pump valve; a controllable evacuating unit that communicates with the chamber of the autoclave through the manifold equipped with an evacuation valve; a controllable blowing unit communicating with the chamber through manifold equipped with a blower valve and configured for blowing cooled hydrogen gas through the chamber; a controllable compressing unit communicating with the chamber through the manifold coupled to a vessel containing pure hydrogen gas used for the filling of the cartridge, and equipped with a compressor valve; a control unit coupled to at least one device selected from the activation element, the pump valve, the vacuum pump, the evacuating unit, the blowing unit, the compressing unit, the evacuation valve, the blower valve, the compressor valve, and configured for controlling operation thereof.

38. The system of claim 37 wherein said housing is made of material that is capable to withstand the pressure values exceeding the pressure of the hydrogen gas maintained in said cylindrical voids of the cartridge after the filling.

39. The system of claim 37 wherein said cartridge includes a case and an assembly structure formed of plurality of closely packed hollow microcylinders arranged in the case, the microcylinders having sealed ends, thereby defining said cylindrical voids.

40. The system of claim 39 wherein the activation element includes a controllable electrically heating element arranged within the cartridge.

41. The system of claim 40 wherein said electrically heating element includes a wire woven throughout the assembly structure of the microcylinders such that folded segments of the wire are located in inter-cylinder spaces.

42. The system of claim 37 wherein the cartridge includes a monolithic block having a plurality of cylindrical cavities formed therein, where ends of the cylindrical cavities distal to the activation tool are sealed, whereas opposite ends of the cylindrical cavities proximate to the activation tool are covered with a hydrogen diffuser plate, thereby defining said cylindrical voids.

43. The system of claim 42 wherein said activation element includes a controllable radiation source configured to provide photo-enhanced diffusion of hydrogen through said hydrogen diffuser plate when the plate is illuminated by radiation of a predetermined frequency range.

44. The system of claim 42 wherein said activation element includes a heating layer made of conductive permeable to hydrogen material placed on the hydrogen diffuser plate.

45. The system of claim 37 wherein said controllable vacuum pump is a roughing- down pump.

46. The system of claim 37 wherein said controllable vacuum pump is adapted to vacuumize the chamber up to the pressure of about 10^" — 10^" torrs.

47. The system of claim 37 comprising a pressure sensor operable for producing a gas pressure sensor signal indicative of the pressure in the chamber, the pressure sensor being coupled to the control unit which is responsive to the gas pressure sensor signal and capable of generating a control signal to said at least one device for controlling thereof.

48. The system of claim 37 comprising a temperature sensor operable for producing a gas temperature sensor signal indicative of the temperature within the chamber, the temperature sensor being coupled to the control unit which is responsive to the temperature sensor signals and capable of generating a control signal to said at least one device for controlling thereof.

49. A method of filling a cartridge having a plurality of cylindrical voids adapted for storing hydrogen gas, the method comprising: placing said cartridge into a chamber; vacuumizing said chamber to a predetermined pressure; preparing the cartridge in order to let the hydrogen gas diffuse into said cylindrical voids; and controlled compressing the hydrogen gas in the chamber over a predetermined compression time interval while maintaining the step of preparing the cartridge operating until the pressure in the chamber reaches a predetermined pressure value, thereby providing the hydrogen gas diffusion into said cylindrical voids.

50. The method of claim 49 wherein said cartridge includes a case and an assembly structure formed of plurality of closely packed hollow microcylinders arranged in the case, the microcylinders having sealed ends, thereby defining said cylindrical voids; and wherein said preparing of the cartridge includes heating the microcylinders to a predetermined temperature.

51. The method of claim 50 wherein said predetermined temperature is in the range of300°C-500°C.

52. The method of claim 49 wherein said cartridge includes a monolithic block having a plurality of cylindrical cavities formed therein, where said cylindrical cavities are sealed at one end and covered with a hydrogen diffuser plate at another end; and wherein said preparing of the cartridge includes illuminating said hydrogen diffuser plate by radiation of a predetermined frequency range, thereby to provide photo-enhanced diffusion of hydrogen therethrough.

53. The method of claim 49 wherein said cartridge includes a monolithic block having a plurality of cylindrical cavities formed therein, where said cylindrical cavities are sealed at one end and covered with a hydrogen diffuser plate at another end; and wherein said preparing of the cartridge includes heating the hydrogen diffuser plate to a predetermined temperature.

54. The method of claim 49 wherein said predetermined pressure value is up to about 3000 atm.

55. The method of claim 49 wherein said predetermined compression time interval is in the range of several minutes to several hours.

56. The method of claim 49 further comprising the steps of: terminating said preparing of the cartridge, and said controlled hydrogen gas compressing; depressurizing the chamber; and blowing cooled hydrogen gas through the chamber.

57. The method of claim 49 further comprising the steps of: terminating said preparing of the cartridge, while maintaining the hydrogen gas compressing step to operate, thereby to keep the pressure in the chamber at the maximal value over the time interval until the cartridge is returned to the condition of small hydrogen permeability; and depressurizing the chamber.