WO2021213255A1

WO2021213255A1 - Energy storage system and method of boosting an electrical power for outputting to a load

Info

Publication number: WO2021213255A1
Application number: PCT/CN2021/087673
Authority: WO
Inventors: Brandon Boon Soon NG; Shabab HUSSAIN; Luciano GURGEL VALENTE; Lok Shu KWAN; Jahan Zaib ALI; Clayton Ka Luen IP
Original assignee: Ampd Energy Limited
Priority date: 2020-04-20
Filing date: 2021-04-16
Publication date: 2021-10-28
Also published as: EP4140008A1

Abstract

An energy storage system includes an electrical input adapted to connect to an external power source; an electrical output adapted to connect to a load; a power bus connected between the electrical input and the electrical output; and a battery subsystem connected to the power bus. The energy storage system is adapted to be switched between a first mode in which the battery subsystem is recharged by electrical power received from the electrical input via the power bus, and a second mode in which the battery subsystem discharges to boost the electrical power received from the electrical input via the power bus for outputting to the electrical output. The disclosed system and method are especially useful in scenarios where an electrical source may not be suitable for powering a high-demand electrically operated loads or equipment.

Description

Energy Storage System and Method of Boosting an Electrical Power for Outputting to a Load

CROSS-REFERENCE TO RELATED APPLICATION

This application claims benefit of U.S. Provisional Application having Serial No. 63/012,084 filed on 20 Apr 2020 and Hong Kong application No. 32020012196.2 filed on 23 July 2020, which are hereby incorporated by reference in its entirety.

FIELD OF INVENTION

The present invention generally relates to energy storage systems; specifically, to energy storage systems used as a device to provide electrical energy to devices, equipment and/or loads, especially in situations where the existing electrical infrastructure is not suitable to power such devices, equipment and/or loads and/or where it may not be economically feasible or operationally practical to build suitable electrical infrastructure to power such devices, equipment and/or loads.

BACKGROUND OF INVENTION

Various industries use electrically operated equipment in their operations. An existing grid mains connection may not be available or the existing grid mains connection may not be suitable to power such equipment. Furthermore, it may be uneconomic or impractical to extend a grid mains connection of sufficient capacity to the location of such equipment. By contrast, a diesel or fossil-fuel generator may be used to provide sufficient power to such equipment and can be transported to most locations. As a result, various industries commonly use diesel or fossil-fuel generators to provide the electrical power required to operate such equipment.

Generators however, create significant amounts of carbon emissions and air quality pollutants. Generators also need to be switched off regularly for refueling, resulting in frequent interruptions to the operations of the equipment being powered by such generators.

SUMMARY OF INVENTION

In the light of the foregoing background, it is an object of the present invention to provide an innovative energy storage system.

Accordingly, provided herein is an alternate system which is capable of providing power to equipment which, when compared to a generator or a sole electrical source, results in lower emissions of carbon and air quality pollutants, and which reduces the frequency of operational interruption to such equipment.

In some embodiments, the system boosts the electrical power from incoming power source (e.g. mains electricity) for outputting to high-demand electrically operated equipment.

Accordingly, one embodiment provides an energy storage system which includes an electrical input adapted to connect to an external power source; an electrical output adapted to connect to a load, wherein the external power source is not sufficient to directly power up the load; a power bus connected between the electrical input and the electrical output; and a battery subsystem comprising at least one rechargeable battery string connected to the power bus. The energy storage system is adapted to be switched between a first mode in which the battery subsystem is recharged by electrical power received from the electrical input via the power bus, and a second mode in which the battery subsystem discharges to boost the electrical power received from the electrical input via the power bus for outputting to the electrical output.

In some embodiments, in the second mode the electrical power received from the electrical input is boosted for its power capacity.

In some embodiments, in the first mode the electrical power received from the electrical input is directly outputted to the electrical output.

According to a variation of the disclosed embodiments, the electrical input is an AC input, and the electrical output is an AC output. The power bus is a DC bus.

According to another variation of the disclosed embodiments, the energy storage system further comprises a rectifier coupled between the electrical input and the power bus; and an inverter coupled between the power bus and the electrical output.

According to another variation of the disclosed embodiments, the rectifier comprises a plurality of modular rectifier units that are adapted for easy insertion or removal, wherein the number of the modular rectifier units is configured to be adjusted for a range of the power capacity.

According to another variation of the disclosed embodiments, the inverter comprises a plurality of modular inverter units that are adapted for easy insertion or removal, wherein the number of the modular inverter units is configured to be adjusted for a range of the power capacity.

In some embodiments, the number of the modular inverter units and the battery strings is determined such that the inverter and the battery subsystem are capable of meeting the peak power demand of the load.

In some embodiments, the rectifier provides the power capacity less than 63 kilowatts and the inverter provides the power capacity greater than 250 kilowatts.

In some embodiments, the battery subsystem provides an energy storage capacity greater than 150 kilowatt-hours.

In some embodiments, the battery string is comprised of a plurality of series and/or parallel connected battery modules, and each of the battery modules is further comprised of a plurality of series and/or parallel connected battery cells.

According to a further variation of the disclosed embodiments, the energy storage system is further adapted to be switched to a third mode in which the battery subsystem discharges to provide battery power to the electrical output without the electrical power received from the electrical input.

In one implementation, the energy storage system has the form factor of a shipping container.

In some embodiments, the external power source is a mains grid, a generator, or a combination thereof, wherein the generator is selected from the group consisting of a solar PV system, a wind generator, a wind turbine, a fuel cell, a diesel generator, an internal combustion engine, an alternator, or any combination thereof.

In some embodiments, the generator is built into the shipping container of the energy storage system.

According to a further variation of the disclosed embodiments, the energy storage system comprises a housing of a shipping container; an electrical input adapted to connect to an external power source; an electrical output adapted to connect to a load of high-power consumption wherein the external power source is not sufficient to directly power up the load; a power bus connected between the electrical input and the electrical output; a battery subsystem comprising of at least one rechargeable battery string connected to the power bus; a rectifier coupled between the electrical input and the power bus; and an inverter comprising a plurality of modular inverter units coupled between the power bus and the electrical output; wherein the power bus, the battery subsystem, the rectifier and the inverter are housed in the housing, and the number of the modular inverter units and the battery strings is determined such that the inverter and the battery subsystem are capable of meeting a peak power demand of the load; and wherein the energy storage system is adapted to be switched between a first mode in which the battery subsystem is recharged by electrical power received from the electrical input via the power bus, and a second mode in which the battery subsystem discharges to boost the electrical power received from the electrical input via the power bus for outputting to the electrical output coupled to the load so as to power up the load.

According to another aspect of the invention, a method of boosting an electrical power for outputting to a load comprises the steps of detecting the presence of an external power source, wherein the external power source is not sufficient to directly power up the load; receiving an electrical power from an electrical input coupled to the external power source, wherein the external power source is present; discharging a battery subsystem to obtain a battery power; and boosting the electrical power using the battery power for outputting to an electrical output coupled with the load.

In some embodiments, the electrical power from the electrical input is AC power. The method further contains the step of rectifying the electrical power to DC power. Additionally or alternatively, the electrical output is an AC output. The method further comprises the step of transforming a boosted DC power to AC power for outputting.

In some embodiments, a method of providing electrical power to a machine using the energy storage system comprises: at the energy storage system, continuously receiving the electrical power from the electrical input; storing the electrical power in the battery subsystem during a first time period; and providing at the electrical output the electrical power to said machine during a second time period; whereby a difference between the electrical power from the electrical input and a power demand of the machine during the second time period is provided by discharging the battery subsystem.

In some embodiments, the inverter comprises a plurality of modular inverter units, and the method further comprising: configuring the number of the modular inverter units and the battery strings by controlling a plurality of electrical switches adapted to power on and off each of the modular inverter units and the battery strings in the energy storage system, the electrical switches being coupled to the modular inverter units and the battery strings, such that the inverter and the battery subsystem are capable of meeting the peak power demand of the load.

In some embodiments, the method of providing electrical power to the machine using the energy storage system further comprises: detecting the presence of the external power source; in response to no presence of the external power source, discharging the battery subsystem for outputting to the electrical output so as to power up the load.

In another embodiment, the step of configuring the number of the modular inverter units and the battery stings and/or battery modules further comprises: obtaining a rated power of the machine and the external power source; based on the rated power of the machine and the external power source, determining the number of the modular inverter units and the battery strings required for powering up the machine; and controlling on-off status of the electrical switches coupled to the modular inverter units and the battery strings.

In some embodiments, the machine requires the power demand greater than 50 kilowatts. In another embodiment, the electrical power from the electrical input is not more than 50 kilowatts.

Therefore, discloses herein are energy storage systems for providing electrical power to electrically operated loads or equipment. Such a system may be especially useful in scenarios where an electrical source may not be sufficient for powering such electrically operated loads or equipment. The energy storage system, in one embodiment, is comprised of a rectifier, an inverter and a battery subsystem. With the battery power stored in the battery subsystem, the input electrical power can be boosted for example in terms of power capacity. In one example, an input electrical power of not more than 50 kilowatts which is connected to the power bus, can be boosted by the energy storage system to achieve an output electrical power which is more than 50 kilowatts of power.

On the other hand, some implementations of the energy storage system are in the dimension and specification of standard shipping containers, for example 8ft or 10ft containers. Therefore, it is extremely easy and convenient to transport the energy storage system to any worksite with trucks.

By adopting the battery subsystem (e.g. Li-ion battery modules) , some embodiments of the invention provide further advantages to completely replace the dirty, noisy and hazardous diesel generators. In terms of environment impacts, the energy storage system could be up to thirty times quieter than a diesel generator, which is ideal for urban environments where the engine noise and vibration of a generator can be a disturbance. The energy storage system also produces zero emissions, with none of the harmful CO, NOx, PM or SO ₂ emissions of a diesel generator, allowing it for use in areas with poor ventilation. The energy storage system also eliminates diesel handling, spills and diesel fires. The lack of moving parts reduces the frequency of maintenance of the system significantly. Internet connectivity enables remote monitoring, device management, remote troubleshooting and data analytics. An automatic recharging means that nearly zero management and supervision by personnel once installed. Lastly, with the form factor of a shipping container the energy storage system is plug-and-play, which could replace most large diesel generators between 200-600kVA, and can be installed and be ready for operation in under 2 hours.

In one embodiment it is provided a general method for determining the minimum capacity of the energy storage system to support the electrically operated load, the method allowing for sources with different characteristics and loads with different characteristics.

Another embodiment provides method of providing electricity to a machine or machines requiring power greater than 50 kilowatts using an energy storage system comprising continuously charging the battery from a lower power electricity input of not more than 50 kilowatts; storing the electricity in the battery; and providing at the output the electricity to such machine or machines requiring power greater than 50 kilowatts; whereby the power difference between the input and output is provided by the battery.

These and additional features provided by the embodiments described herein will be more fully understood in view of the following detailed description, in conjunction with the drawings.

BRIEF DESCRIPTION OF FIGURES

The foregoing and further features of the present invention will be apparent from the following description of embodiments which are provided by way of example only in connection with the accompanying figures, of which:

FIG. 1 provides a high-level diagram of the connections of an energy storage system, which is recharged by a source while simultaneously being used to provide electrical power to a load;

FIG. 2 illustrates an exemplary embodiment of the architecture of an energy storage system of the present invention;

FIG. 3 illustrates a schematic diagram of an energy storage system according to an embodiment of the present invention;

FIG. 4 illustrates an energy storage system equipped with a shipping container according to an embodiment of the present invention.

FIG. 5 illustrates a method for boosting an electrical power in accordance with an example embodiment.

FIG. 6 illustrates a method for providing an electrical power in accordance with an example embodiment.

In the drawings, like numerals indicate like parts throughout the several embodiments described herein.

DETAILED DESCRIPTION

In the claims which follow and in the preceding description, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

As used herein and in the claims, “couple” or “connect” refers to electrical coupling or connection either directly or indirectly via one or more electrical means unless otherwise stated.

A “source” for purposes of embodiments of the present invention may be any electrical source. The source can be, by way of example only but not by limitation, the mains grid, a solar PV system, a wind generator, a wind turbine, a fuel cell, a diesel generator or any combination of the previous.

A “load” for purposes of embodiments of the present invention may be any device which consumes power.

As used herein and in the claims, “modular unit” means a suitable hardware component that fulfills a desired function by combining one or more of the components.

As used herein and in the claims, “battery cell” refers to an individual electrochemical cell comprising electrodes and electrolyte, configured to supply electricity in electrical equipment. In some embodiments, “battery cell” is rechargeable such that “battery cell” is capable of being charged repeatedly.

As used herein and in the claims, “battery module” and “battery pack” may be used interchangeably and refer to a unit that comprises a plurality of series and/or parallel connected battery cells.

As used herein and in the claims, “battery string” is intended to broadly refer to a unit that comprises a plurality of series and/or parallel connected battery modules.

As used herein and in the claims, “box” refers to a shipping container where all the components of the energy storage system are housed within.

Embodiments of the present invention provide a new apparatus and method for providing electrical power to electrically operated equipment in situations where it may be uneconomic or impractical to use a grid mains connection to do so. The following description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements. Various modifications to the disclosed embodiment and the generic principles and features described herein will be readily apparent to those skilled in the art. Thus, the present invention is not intended to be limited to the embodiments shown but is to be accorded the widest scope consistent with the principles and features described herein.

Battery or battery cells may refer to any of a variety of different rechargeable configurations and cell chemistries including, but not limited to, lithium-ion, lithium-ion polymer, nickel-metal hydride, nickel cadmium, nickel hydrogen, nickel zinc, silver zinc, zinc-air, lead-acid, vanadium redox, vanadium flow or other chargeable type or configuration. The terms “battery” , “battery system” and “battery subsystem” may be used interchangeably and as used herein refer to a device which has the capability to be charged and discharged such as a battery, battery pack, capacitor, supercapacitor or ultracapacitor.

FIG. 1 provides an exemplary implementation of an energy storage system (ESS) 100 according to a first embodiment of the invention, which is used to provide electrical power to an electrically powered load 101, and which is recharged by a source 102.

In one implementation, the source 102 is a small and reliably available-on-demand electrical supply, such as a small, temporary grid mains connection (which would ordinarily be insufficient to power the load 101) . In another implementation, the source 102 is an irregular and uncontrolled electrical supply, such as a solar panel and/or a wind turbine. In a further implementation, the source 102 is a controllable electrical supply which is only available for short durations each period due to any one or any combination of noise, environmental or regulatory restrictions, such as a diesel generator which is switched on periodically for a duration no longer than is necessary to sufficient recharge the energy storage system 100 to a level where the energy storage system 100 is able to provide power to the load 101 until the next period when the diesel generator can be switched on. In yet a further implementation, the source 102 is any combination of a small and reliably available-on-demand electrical supply and/or an irregular and uncontrolled electrical supply and/or a controlled electrical supply which is only available for short durations each period. In all the embodiments described in this paragraph, the source 102 would ordinarily be unsuitable to directly provide power to the load 101.

In some examples, the energy storage system comprises an electrical input adapted to connect to an external power source and an electrical output adapted to connect to a load, wherein the external power source is not sufficient to directly power up the load. The energy storage system further comprises a power bus connected between the electrical input and the electrical output and a battery subsystem comprising a plurality of rechargeable battery strings and/or battery modules connected to the power bus. Additionally, the energy storage system is adapted to be switched between a first mode in which the battery subsystem is recharged by electrical power received from the electrical input via the power bus, and a second mode in which the battery subsystem discharges to boost the electrical power received from the electrical input via the power bus for outputting to the electrical output.

The energy storage system further comprises a rectifier coupled between the electrical input and the power bus and an inverter coupled between the power bus and the electrical output.

By way of example, as used herein and in the claims, “boost” means to add an electrical power from the battery subsystem to the electrical power from the external power source by discharging the battery subsystem to power up the load.

The external power source may be a mains grid, a generator, or a combination thereof, wherein the generator is selected from the group consisting of a solar PV system, a wind generator, a wind turbine, a fuel cell, a diesel generator, an internal combustion engine, an alternator, or any combination thereof.

FIG. 2 shows, according to another embodiment of the invention, an energy storage system 200, such as may be used to implement the present invention. The present invention is not limited to this particular implementation of the energy storage system. As shown in FIG. 2, the energy storage system 200 includes a battery subsystem 210, a rectifier 211 and an inverter 212. A power bus which is the DC bus 213 electrically couples the battery subsystem 210, rectifier 211 and inverter 212. An external power source connects to an electrical input 240 and in turn to the rectifier 211. The external power source is an AC source similar to those mentioned above, and thus the electrical input 240 is an AC input. On the other hand, the load 201 is an AC load which is connected to an electrical output 250 and thus the electrical output 250 is an AC output. The electrical output 250 is further connected to the inverter 212. The battery subsystem 210 as shown in FIG. 2 contains multiple battery cells 210a connected in series.

The DC bus 213 is energised by the rectifier 211 or the battery subsystem 210 or both the rectifier 211 and the battery subsystem 210, depending on the availability of the source 202 and the state-of-charge of the battery subsystem 210. The energy storage system 200 is therefore adapted to work under different working modes and being switchable between these working modes, including a first mode in which the battery subsystem 210 is recharged by electrical power received from the electrical input 240 via the DC bus 213, a second mode in which the battery subsystem 210 discharges to boost the electrical power received from the electrical input 210 via the DC bus 213 for outputting to the electrical output 250, and a third mode in which the battery subsystem 210 discharges to provide battery power to the electrical output 250 when there is no electrical power received from the electrical input 240.

In the first mode, the AC electrical power received from the electrical input 240 also powers the load 201 directly via the DC bus 213 besides recharging the battery subsystem 210, although as mentioned above such a direct powering to the load 201 might not be sufficient for the normal operation of the load 201. In the first mode, the DC bus 213 provides DC power to the inverter 212, where the DC power is converted by the rectifier 211 from the inputted AC power. The inverter 212 then provides AC power to the load 201. When the power drawn by the load 201 through the inverter 212 is less than the power available from the source 202 through the rectifier 211, and when the battery subsystem 210 is not full, the battery subsystem 210 is recharged through the DC bus 213.

When the power drawn by the load 201 through the inverter 212 is greater than the power available from the source 202 through the rectifier 211, and when the battery subsystem 210 is not empty, the battery 210 is discharged through the DC bus 213 in the second mode. To fulfill the requirements of the second mode, the inverter 212 and the battery subsystem 210 is sized such that they are capable of meeting the maximum electrical requirements of the load 201. For example, if the load 201 requires a three-phase electrical supply and has a peak power demand of 300 kilowatts, then i) the inverter 212 shall be one which provides sufficient power to meet the load’s peak power demand; and ii) the battery subsystem 210 shall be sized such that it is capable of providing sufficient power to the inverter 212, in order for the inverter 212 to provide sufficient power to meet the load 201’s peak power demand.

In the third mode, when there is no source 202 available to the energy storage system 200, the battery subsystem 210 then becomes the only power source to supply the load 201. All the power outputted to the load 201 then comes from the battery power from the battery subsystem 210 as converted by the inverter 212.

Although not shown, the battery subsystem 210 may further contain further subsystems and components such as a battery management system, one or more DC-DC converters, one or more switches, relays, contactors, one or more disconnect or overcurrent protection devices or other electrical protection device or devices in order to provide safe, reliable and long-lasting operation.

Although not shown, the energy storage system 200 may further contain other auxiliary systems, subsystems or components, such as, but not limited to, heat pumps, heat exchangers, air-conditioners, cooling fans, thermal management systems, one or more energy management systems, a fire detection system, a fire suppression system, a flood sensing system, one or more human machine interfaces, internal communication systems and external communication systems, in order to provide safe, reliable and long-lasting operation and ease of management of energy storage system 200.

A further consideration in determining the capacity of battery subsystem 210 is ensuring that its state-of-charge, at all times, remains above the threshold value whereby the energy storage system 200 is shut down, accounting for the net rate of charging or discharging of the battery subsystem 210 through the DC bus 213.

According to some embodiments, an energy storage system comprises a housing of a shipping container, an electrical input adapted to connect to an external power source, an electrical output adapted to connect to a load of high-power consumption. Here, the external power source is not sufficient to directly power up the load. The energy storage system further comprises a power bus connected between the electrical input and the electrical output, a battery subsystem comprising of a plurality of rechargeable battery cells connected to the power bus, a rectifier coupled between the electrical input and the power bus and the electrical output.

The power bus, the battery subsystem, the rectifier and the inverter are housed in the housing, and the number of the modular inverter units and the battery strings and/or battery modules are determined such that the inverter and the battery subsystem are capable of meeting a peak power demand of the load. Further, the energy storage system is adapted to be switched between a first mode in which the battery subsystem is recharged by electrical power received from the electrical input via the power bus, and a second mode in which the battery subsystem discharges to boost the electrical power received from the electrical input via the power bus for outputting to the electrical output so as to power up the load.

Turning now to FIG. 3, an electrical schematic of another embodiment of the invention is shown. In this embodiment, the source 301 is a 20 kilowatt, three-phase utility mains connection and the load 302 is a 300 kilowatt, three-phase electrical distribution panel which is connected to a tower crane. It should be noted that in other variations of the embodiments, the source may be an electrical supply required with a few kilowatts to under 50 kilowatts depending on various applications. The energy storage system is able to deliver at the output the necessary power for equipment (such as tower crane, site office, passenger or material hoist, etc. ) to operate. In some further variations, the output power is significantly greater than the input power. In some cases, the output provides greater than 50 kilowatts.

In the embodiment of FIG. 3, energy storage system 300 is comprised of a battery subsystem 310, a three-phase rectifier with a 63 kilowatt power rating 311, a three-phase inverter with a 315 kilowatt power rating 312 and a DC bus 313. In this embodiment, inverter 312 is connected to 300 kilowatt delta-wye transformer 314 in order to allow single-phase loads to be connected. The external power source 301 connects to the rectifier 311 via an electrical input 340, and the load 302 connects to the transformer 314 via an electrical output 350. There are also multiple circuit breakers 360 in the circuit of the energy storage system 300 for safety purposes.

In this embodiment, the battery subsystem 310 is comprised of a plurality of battery modules with each individual battery module 310a further comprised of a 224 lithium-ion battery cells in a 14S16P configuration. In this embodiment, fifteen battery modules 310a are connected in series to form a single “battery string” 310b and a total of seven battery strings 310b are connected to the DC bus 313, providing a total nominal energy storage capacity of 300 kilowatt-hours. The battery subsystem 310 in this embodiment is managed by a battery management system 310c, in order to ensure safe, reliable and long-lasting operation. This embodiment further contains a plurality of safety switchgear and further management and control systems including a power conversion subsystem controller 315, energy management system 316, fire detection and suppression system 317, a ‘DC section’ thermal management system 318, an ‘AC section’ cooling system 319, an uninterruptible power supply system 320 to provide a backup electrical supply to the critical management and control systems, a flood detection system 321, a human-machine interface 322, an emergency power off switch 323 and a cellular communication interface 324 in order to ensure safe, reliable and long-lasting operation.

The battery subsystem in FIG. 2 is shown as a series-connected group of battery cells, and the battery subsystem in FIG. 3 is shown as a parallel-connected group of battery strings, where each string contains series-connected battery modules, and each module comprises series-connected battery cells. However, those skilled in the art should realize that the configuration of the battery subsystem may be a combination of series and/or parallel connected battery cells, battery modules, battery packs or battery strings of many different configurations. For example, in one variation the battery subsystem is comprised of a plurality of parallel connected battery strings, which are further comprised of a plurality of series and parallel connected battery cells. In another variation, the battery subsystem is comprised of a plurality of parallel connected battery strings, which are further comprised of a plurality of series connected battery cells. In a further variation, the battery subsystem is comprised of a plurality of series connected battery cells.

By way of example, the rectifier 311 comprises a plurality of modular rectifier units and the inverter 312 comprises a plurality of modular inverter units. These modular units including the battery strings and/or battery modules may be configurable by electrical switches. The number of the modular inverter units, rectifier units and the battery strings and/or battery modules can be configured by controlling a plurality of electrical switches adapted to power on and off each of the modular units in the energy storage system. The electrical switches are coupled to the modular inverter units and the battery strings and/or battery modules, such that the inverter and the battery subsystem are capable of adaptively meeting the peak power demand of the load.

By way of example, configuring the number of the modular inverter units and the number of the battery strings and/or battery modules may be implemented by obtaining a rated power of the machine and the external power source, based on the rated power of the machine and the external power source, determining the number of the modular inverter units and the battery strings and/or battery modules required for powering up the machine, and controlling on-off status of the electrical switches coupled to the modular inverter units and the battery strings and/or battery modules.

All components, subsystems and systems that make up energy storage system 300 are, in this embodiment, enclosed in and protected by a durable and weatherproof shipping container 400, as shown in FIG. 4. Artwork is painted to the exterior of shipping container 400 for aesthetic purposes and to communicate the branding of the energy storage system 300.

For each of the energy storage systems in the embodiment of FIG. 2 or that of FIG. 3, necessary engineering designs have also been made to make the storage system usable, durable and marketable for construction site environments in any weather conditions and any site configurations. This includes making proper arrangements of the accessories or functional provisions on the surface of the energy storage system (in the form factor of a container) that have catered for actual site operations and specific requirements for outdoor usage. Such arrangements may be made to also other container-like energy storage system designs in the spirit of the systems described in the present disclosure.

In particular, take the shipping container 400 as an example, the container 400 contains a plug zone 460 on its side wall. Plugs (not shown) are configured in the plug zone 460 which implement the electrical input and electrical output of the energy storage system as mentioned above. Note that there may be more than one such plug zone 460 on the container 400. The plug zone’s locations and orientation are so designed to avoid flooding, to facilitate easy plugging for site electricians safe uses and to suit the types of electrical equipment that are commonly used on site.

In addition, the arrangement of the battery subsystem (not shown in FIG. 4) inside the container 400 is so designed to have the centre of gravity as close to the centre of the container as possible to avoid tipping or overturning of the container during lifting operation, that suit the safety standard in construction sites.

The outer surfaces of the container 400 are provided with safety notices (not shown) in different languages to suit the use in construction sites where there is no restriction on access around the energy storage unit on site unlike other similar equipment for use in other premises or situation where they are stored in a locked room.

The dimensions, weight and the output performance of the container 400 are inter-related to each other, and the specification of these combinations for the final products relies on the construction domain knowledge and market knowledge.

Following provides some examples of the energy storage system with modular scheme housed in a shipping container, namely Model M and Model L. The examples provided herein are merely for illustrative purposes and are not meant to limit the scope of the invention in any way.

In some embodiments, the Model M or the Model L is a device comprising all the components of the energy storage system housed in a shipping container, as described above. In another embodiment, the Model M or the Model L utilizes a power source which is not sufficient to power a given load, to power up the load. In some embodiments, the Model M or the Model L charges up using a small and continuous grid supply and delivers power to a large, intermittent load. In another embodiment, Both the Model M and the Model L are built on a modular architecture.

In some embodiments, both the Model M and the Model L are identical in appearance and in physical dimensions. In another embodiment, the Model M and the Model L have different electrical capabilities. The difference between the Model M and the Model L are different numbers of inverters, rectifiers, or battery strings/modules/cells.

Table 1. Specification of components in Model M and Model L

Referring to table 1, the power of the inverter 212/312 is the rated power, which is the power the component can sustain for extended periods without overheating. The inverter is capable of handling a 20%overload for up to 1 minute or until it hits its temperature limit, which ever happens sooner, without sustaining damage. In some embodiments, if the cost, size and noise are the same, the more power is better.

In some embodiments, the charging speed of the battery subsystem 210/310 is manually set, up to the capacity of the rectifier 211/311. In another embodiment, the capacity of the rectifier 211/311 is 62.5 kilowatts.

In some embodiments, all the components of the Model M and the Model L are housed within a modified box which measures 3.0 x 2.4 x 2.6 meters. This makes the Model M upgradeable to the Model L, and the Model L can be downgraded to the Model M, simply by adding/removing inverter and battery strings/modules.

In one embodiment, the dimensions of the box for the Model M is smaller than those of the box for the Model L in order to reduce the footprint taken up on already space constrained construction sites. In another embodiment, the dimensions of the box for the Model M is 2.4 x 2.4 x 2.4 meters. In another embodiment of the invention, every component of the energy storage system 100/200/300 is the same in the Model M and the Model L, but the box is smaller and the output transformer 314 is matched to the capacity of the inverter 212/312. In some embodiments, the capacity of the inverter is a rate capacity that is between 200 to 300 kilowatts.

In another embodiment of the invention, every component of the energy storage system 100/200/300 is the same in the Model M and the Model L, but the inverter 210/310 have a significantly higher capacity, and an output transformer 314 with a correspondingly higher capacity.

In another embodiment of the invention, the energy storage system 100/200/300 does not comprise certain auxiliary subsystems such as any one or more of the fire detection and suppression system 317, the ‘DC section’ thermal management system 318, the ‘AC section’ cooling system 319, the uninterruptible power supply system 320, the flood detection system 321, the human-machine interface 322, the emergency power off switch 323 and the cellular communication interface 324. In another embodiment, the energy storage system 100/200/300 combines certain auxiliary subsystems such as the power conversion subsystem controller 315, the energy management system 316 and the cellular communication interface 324, into a single unit.

In another embodiment of the invention, every component of the energy storage system 100/200/300 is the same in the Model M and the Model L, but a battery subsystem 210/310 has a significantly greater capacity. In another embodiment, the capacity of the battery subsystem 210/310 is greater than 252 kilowatt-hours.

In some embodiments, every component of the energy storage system 100/200/300 is the same in the Model M and the Model L, but a battery subsystem 210/310 has 50%less capacity. In another embodiment, the capacity of the battery subsystem 210/310 is 75 kilowatt-hours.

In some embodiments, every component of the energy storage system 100/200/300 is the same in the Model M and the Model L, but the rectifier 211/311 has a higher capacity than 62.5 kilowatts. In another embodiment, every component of the energy storage system 100/200/300 is the same in the Model M and the Model L, but the rectifier 211/311 has a capacity which is 50%less than 62.5 kilowatts.

In another embodiment, every component of the energy storage system 100/200/300 is the same in the Model M and the Model L, but the output delta-wye transformer 314 and/or circuit breaker 360 is omitted.

In another embodiment, every component of the energy storage system 100/200/300 is the same in the Model M and the Model L, but the source is a generator which is built into the box which the Model M or the Model L is built in.

In another embodiment, the generator is any device which converts a fuel into electricity such as an internal combustion engine, an alternator, a fuel cell, a solar PV system, or a wind turbine.

FIG. 5 is a flowchart of a method 500 for boosting an electrical power according to an embodiment of the present invention. The method 500 may be implemented by for example the controller as described above in connection with FIG. 3.

Block 510 states detecting the presence of an external power source. In this embodiment, the external power source is not sufficient to directly power up the load, and thus the energy storage system is to boost the electrical power for functioning the load. In one example, the load requires a power significantly greater than 50 kilowatts. In some embodiments, the load includes tower crane, site office, passenger or material hoist.

Block 520 states, in response to the presence of the external power source, receiving the electrical power from the electrical input coupled to the external power source. By way of example, the electrical power from the electrical input is AC power; the method further comprising the step of rectifying the electrical power to DC power.

Block 530 states discharging a battery subsystem to obtain a battery power. The battery subsystem has been recharged and at block 530 is in a state of discharging.

Block 540 states boosting the electrical power using the battery power for outputting to an electrical output coupled to the load so as to power up the load. This is the process of boosting the electrical power.

In an embodiment where the external power source periodically supplies power, the detection causes different operation modes of the energy storage system. If a presence of the external power source is detected and the power drawn by the load is less than the power available from the source, the battery subsystem is recharged. If no presence of the external power source is detected, the battery subsystem is discharged for outputting to the electrical output so as to power up the load.

By way of example, the electrical output is an AC output and the electrical power from the electrical input is AC power. The method 500 further comprising the step of rectifying the electrical power to DC power and the step of transforming a boosted DC power to AC power for outputting.

FIG. 6 is a flowchart of a method 600 for providing an electrical power to a machine using the energy storage system according to an embodiment of the present invention. The method 600 may be implemented by for example the controller as described above in connection with FIG. 3, and the energy storage system can be any of these described above in connection of FIG. 1 to FIG. 4.

Block 610 states, at the energy storage system, continuously receiving the electrical power from the electrical input. In this embodiment, the external power source is available and constantly supply power.

Block 620 states storing the electrical power in the battery subsystem during a first time period. In one embodiment, the first time period may be when the machine does not require the electrical power from the energy storage system. In another embodiment, the first time period may be any time period when the power drawn by the load is less than the power available from the source.

Block 630 states providing at the electrical output the electrical power to said machine during a second time period, where a difference in power between the electrical power from the electrical input and a power demand of the machine during the second time period is provided by discharging the battery subsystem.

By way of example, the second time period may be when the machine requires the electrical power from the energy storage system, and the electrical power from the external power source is not sufficient to power up the machine.

By way of example, the inverter comprises a plurality of modular inverter units, and the method 600 further comprises configuring the number of the modular inverter units and the battery strings and/or battery modules by controlling a plurality of electrical switches adapted to power on and off each of the modular inverter units and the battery strings and/or battery modules in the energy storage system. The electrical switches are coupled to the modular inverter units and the battery strings and/or battery modules, such that the inverter and the battery subsystem are capable of adaptively meeting the peak power demand of the load.

By way of example, the step of configuring the number of the modular inverter units and the battery strings and/or battery modules further comprises obtaining a rated power of the machine and the external power source; based on the rated power of the machine and the external power source, determining the number of the modular inverter units and the battery strings and/or battery modules required for powering up the machine; and controlling on-off status of the electrical switches coupled to the modular inverter units and the battery strings and/or battery modules.

By way of example, the machine requires the power demand greater than 50 kilowatts. In some embodiments, the electrical power from the electrical input is not more than 50 kilowatts.

One of the application scenarios where the energy storage system 100 may be used is on construction site. Each crane on the construction site can consume a great amount of electricity power while the electricity source may not be suitable directly provide power to the crane. Through the energy storage system, during a first time period, such as during nights when the crane does not work, the battery subsystem in the energy storage system stores up energy. During a second time period, such as during daytime when the crane works, the battery subsystem boosts the power capacity by discharging. In this way, the cranes can work efficiently in some difficult conditions that the electricity source is not suitable by its own for the cranes.

The exemplary embodiments of the present invention are thus fully described. Although the description referred to particular embodiments, it will be clear to one skilled in the art that the present invention may be practiced with variation of these specific details. Hence this invention should not be construed as limited to the embodiments set forth herein.

While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only exemplary embodiments have been shown and described and do not limit the scope of the invention in any manner. It can be appreciated that any of the features described herein may be used with any embodiment. The illustrative embodiments are not exclusive of each other or of other embodiments not recited herein. Accordingly, the invention also provides embodiments that comprise combinations of one or more of the illustrative embodiments described above. Modifications and variations of the invention as herein set forth can be made without departing from the spirit and scope thereof, and, therefore, only such limitations should be imposed as are indicated by the appended claims.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in any country.

In the description herein, numerous specific details are provided to provide a thorough understanding of the embodiments of the present invention. One skilled in the relevant art will recognise, however, that an embodiment of the invention can be practiced without one or more of the specific details, or with other apparatus, systems, subsystems, assemblies, methods, components, materials, parts and/or the like. Well-known structures, materials or operations are not specifically shown or described in detail to avoid obscuring aspects of embodiments of the present invention.

It will be appreciated that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application.

Claims

An energy storage system, comprising:

an electrical input adapted to connect to an external power source;

an electrical output adapted to connect to a load, wherein the external power source is not sufficient to directly power up the load;

a power bus connected between the electrical input and the electrical output; and

a battery subsystem comprising at least one rechargeable battery string connected to the power bus;

wherein the energy storage system is adapted to be switched between a first mode in which the battery subsystem is recharged by electrical power received from the electrical input via the power bus, and a second mode in which the battery subsystem discharges to boost the electrical power received from the electrical input via the power bus for outputting to the electrical output.
The energy storage system of claim 1, wherein in the second mode the electrical power received from the electrical input is boosted to meet a power demand of the load.
The energy storage system of any one of the preceding claims, wherein in the first mode the electrical power received from the electrical input is directly outputted to the electrical output.
The energy storage system of any one of the preceding claims, wherein the electrical input is an AC input, and the electrical output is an AC output; the power bus being a DC bus.
The energy storage system of claim 4, further comprising:

a rectifier coupled between the electrical input and the power bus; and

an inverter coupled between the power bus and the electrical output.
The energy storage system of claim 5, wherein the rectifier comprises a plurality of modular rectifier units that are adapted for easy insertion or removal, wherein the number of the modular rectifier units is configured to be adjusted for a range of the power capacity.
The energy storage system of claims 5 or 6, wherein the inverter comprises a plurality of modular inverter units that are adapted for easy insertion or removal, wherein the number of the modular inverter units is configured to be adjusted for a range of the power capacity.
The energy storage system of claim 7, wherein the number of the modular inverter units and the battery strings is determined such that the inverter and the battery subsystem are capable of meeting a peak power demand of the load.
The energy storage system of claim 8, wherein the rectifier provides the power capacity less than 63 kilowatts and the inverter provides the power capacity greater than 250 kilowatts.
The energy storage system of claims 8 or 9, wherein the battery subsystem provides an energy storage capacity greater than 150 kilowatt-hours.
The energy storage system of any one of preceding claims, wherein the battery subsystem comprises a plurality of parallel connected battery strings, wherein each of the battery strings is comprised of a plurality of series and/or parallel connected battery modules, and each of the battery modules is further comprised of a plurality of series and/or parallel connected battery cells.
The energy storage system of claim 5, wherein the energy storage system is further adapted to be switched to a third mode in which the battery subsystem discharges to provide battery power to the electrical output without the electrical power received from the electrical input.
The energy storage system of any one of the preceding claims, wherein the energy storage system has the form factor of a shipping container.
The energy storage system of claim 13, wherein the external power source is a mains grid, a generator, or a combination thereof, wherein the generator is selected from the group consisting of a solar PV system, a wind generator, a wind turbine, a fuel cell, a diesel generator, an internal combustion engine, an alternator, or any combination thereof.
The energy storage system of claim 14, wherein the generator is built into the shipping container of the energy storage system.
An energy storage system, comprising:

a housing of a shipping container;

an electrical input adapted to connect to an external power source;

an electrical output adapted to connect to a load of high-power consumption, wherein the external power source is not sufficient to directly power up the load;

a power bus connected between the electrical input and the electrical output;

a battery subsystem comprising of at least one rechargeable battery string connected to the power bus;

a rectifier coupled between the electrical input and the power bus; and

an inverter comprising a plurality of modular inverter units coupled between the power bus and the electrical output;

wherein the power bus, the battery subsystem, the rectifier and the inverter are housed in the housing, and the number of the modular inverter units and the battery strings is determined such that the inverter and the battery subsystem are capable of meeting a peak power demand of the load; and

wherein the energy storage system is adapted to be switched between a first mode in which the battery subsystem is recharged by electrical power received from the electrical input via the power bus, and a second mode in which the battery subsystem discharges to boost the electrical power received from the electrical input via the power bus for outputting to the electrical output so as to power up the load.
A method of boosting an electrical power for outputting to a load, comprising:

detecting the presence of an external power source, wherein the external power source is not sufficient to directly power up the load;

in response to the presence of the external power source, receiving an electrical power from an electrical input coupled to the external power source;

discharging a battery subsystem to obtain a battery power; and

boosting the electrical power using the battery power for outputting to an electrical output coupled to the load.
The method of claim 17, wherein the external power source periodically supplies power, the method further comprising:

in response to no presence of the external power source, discharging the battery subsystem for outputting to the electrical output so as to power up the load.
A method of providing electrical power to a machine using the energy storage system of any of claims 1-15, comprising:

at the energy storage system, continuously receiving the electrical power from the electrical input;

storing the electrical power in the battery subsystem during a first time period; and

providing at the electrical output the electrical power to said machine during a second time period;

whereby a difference in power between the electrical power from the electrical input and a power demand of the machine during the second time period is provided by discharging the battery subsystem.
The method of claim 19, wherein the inverter comprises a plurality of modular inverter units, and the method further comprising:

configuring the number of the modular inverter units and the battery strings by controlling a plurality of electrical switches adapted to power on and off each of the modular inverter units and the battery strings in the energy storage system, the electrical switches being coupled to the modular inverter units and the battery strings, such that the inverter and the battery subsystem are capable of meeting the peak power demand of the load.
The method of claim 20, wherein the step of configuring the number of the modular inverter units and the battery strings further comprises:

obtaining a rated power of the machine and the external power source;

based on the rated power of the machine and the external power source, determining the number of the modular inverter units and the battery strings required for powering up the machine; and

controlling on-off status of the electrical switches coupled to the modular inverter units and the battery units.