DE102009058955A1 - Volume compensation arrangement for cooling- or heating medium of battery, has flexible housing on which prestressed elastic element acts or has rigid housing which is arranged to another flexible housing - Google Patents

Abstract

The volume compensation arrangement has a flexible housing on which a prestressed elastic element acts or has a rigid housing which is arranged to another flexible housing, on which another prestressed elastic element acts. The elastic elements are operated in an area, in which the force is independent of the spring stroke.

Description

TECHNICAL AREA

The invention relates to a volume compensation arrangement for a cooling / heating medium of a rechargeable battery.

STATE OF THE ART

Today, more and more electrical and electronic devices are used, which can be operated independently of a power grid. More and more powerful devices and the desire for the longest possible operating time require more and more powerful accumulators. As a rule, these should be as small and light as possible, yet have high energy content. In order to meet these contradictory demands, which are particularly important in the construction of electric vehicles, great efforts have recently been made. Nevertheless, there is still room for improvement in the field of accumulator technology.

DISCLOSURE OF THE INVENTION

The object of the present invention is therefore to specify an improved accumulator or a volume compensation arrangement therefor, in particular for an accumulator for an electric motor vehicle.

The object of the invention is achieved with a volume compensation arrangement according to claim 1, namely by a volume compensation arrangement for a cooling / heating medium (or for the composite of cooling / heating elements) of an accumulator, comprising a flexible housing, act on which prestressed disc springs or through a volume compensation arrangement for a cooling / heating medium of a rechargeable battery, comprising a rigid housing in which a flexible housing is arranged, act on which prestressed elastic elements, in particular disc springs.

As already mentioned, the volume of the cells of accumulators varies according to state of charge and temperature. This is usually accompanied by a change in volume of the cells adjacent to the cooling / heating elements. A volume compensation arrangement according to the invention now makes possible the volume changes mentioned, since a liquid which is not compressible, such as, for example, gases, is usually used as the cooling medium. As elastic elements, of course, all types of springs, especially coil springs, as well as, for example, elastic plastic foams into consideration.

It is advantageous in a volume compensation arrangement when the elastic elements, in particular disc springs, are operated in a region in which the force is essentially independent of the spring travel. In this way, a substantially constant pressure in the accumulator can be achieved independently of the extent of the cells.

Further advantageous embodiments and modifications of the invention will become apparent from the dependent claims and from the description in conjunction with the figures of the drawing.

The invention is also achieved by a cooling / heating element, namely by a cooling / heating element for an accumulator, comprising a cooling surface with a first boundary, which is provided for body contact to a first cell of the accumulator, and a second boundary, which Body contact is provided to a second cell of the accumulator, wherein the two boundaries are elastically connected to each other.

The cells of a rechargeable battery generate waste heat during operation, which is usually absorbed by the large thermal mass of the cells themselves. An active cooling is therefore usually required only at very high outside temperatures or at a very long operating time of a battery or when "power cells" such. B. are used in a hybrid vehicle that are charged or discharged several times within a few minutes (the thermal mass is then no longer very fast). By contrast, heating is advantageous even at moderately low temperatures because the chemical reaction of most cell types comes to a standstill.

In addition, the volume of a cell varies depending on the state of charge. According to the invention, the cooling / heating element can heat or cool the cells as needed, and compensate for volume fluctuations of the cells and exert pressure forces on the cells. Among other things, these pressure forces serve to fix the cells, which are usually located in a plastic bag. Overall, the individual cooling / heating elements in the stack form a very stable accumulator housing.

In addition, the cooling / heating elements can of course be used in addition to the use of the cells for the temperature control of other components in the accumulator, for example for the heating / cooling of electronic assemblies.

Finally, the cooling / heating elements form as it were "fire walls" between the individual cells. Overheating, overcharging or other improper use can lead to a so-called "thermal runaway". In this case, the entire stored in a cell chemical and electrical energy is implemented within 5 to 25 seconds. This creates locally very high temperatures of over 700 ° C, which can ignite the adjacent cells because of the high packing density of the cells. The cooling / heating elements prevent heat and fire from spreading to neighboring cells that have not yet been affected by the thermal runaway.

It is advantageous in the case of a cooling / heating element according to the invention if elastic webs for connecting the first and second boundaries are provided in the interior of the cooling / heating element in the region of the cooling surface. In this way, both a good cohesion of the cooling / heating element as well as a possibility for Votumsänderung of the cooling / heating element can be achieved.

It is advantageous in a cooling / heating element according to the invention, when the webs are configured meandering. Due to the meander shape, the webs can be easily deformed, so that the resistance to a change in volume is only slight. In addition, the meandering shape causes a certain minimum distance between the boundaries to be maintained when the cooling / heating element is compressed, since with excessive compression the legs of a meandering arc come to lie on top of each other and can not be compressed further or only under considerable force.

It is advantageous in a cooling / heating element according to the invention, when the webs extend obliquely from the first boundary to the second boundary. Again, the resistance to a vote change is low. Similarly, with excessive compression of the cooling / heating element also a minimum distance between its limits is maintained, which in this case corresponds approximately to the thickness of the web.

It is advantageous in the case of a cooling / heating element according to the invention if spacer knobs are provided in the region of the cooling surface, in particular without connecting the first limiting surface to the second. In this way, a minimum distance between the boundaries of the cooling / heating element can also be maintained, in particular if it is dispensed with elastic webs simpler manufacturability. The nubs can be arranged on one side or two sides.

It is advantageous in a cooling / heating element according to the invention, if a rigid edge is provided, which is elastically connected to the boundaries of the cooling / heating element. The rigid edge allows good stackability of the cooling / heating elements. Furthermore, it can accommodate inlet and outlet channels for the cooling medium. Finally, the rigid edge ensures the safe positioning of the cells during assembly of the accumulator. Once the accumulator has been completed, the cooling / heating elements in a composite form a housing for all cells and fix each cell separately.

It is advantageous in a cooling / heating element according to the invention, when the rigid edge is at least as high as a cell, the thickness of the boundaries and a minimum distance between the boundaries. In this case, the rigid edge also ensures that a certain minimum distance between the individual cooling / heating elements is maintained. In this way it can be ensured that the individual cooling / heating elements of a stack are compressed or expanded more or less the same. Strong local differences in the cooling / heating power can thus be avoided.

It is advantageous in a cooling / heating element according to the invention, if a flow aperture is provided at the edge of the cooling surface, which ensures a substantially constant inflow or outflow of a cooling / heating medium regardless of the distance between the first and second boundary. A constant inflow and / or outflow also contributes to the cooling / heating power within the accumulator not varying too much.

It is advantageous in a cooling / heating element according to the invention, when a flow aperture is provided at the edge of the cooling surface, which throttles an inlet of a cooling / heating medium with increasing distance between the first and second boundary. In this variant, the inlet is throttled with increasing distance between the first and second boundary and increased with decreasing distance. In this way, the pressure in the cooling surface is controlled so that decreasing pressure counteracts a further increase in the distance between the boundaries and vice versa.

It is advantageous in a cooling / heating element according to the invention, if a flow diaphragm is provided at the edge of the cooling surface, which throttles a flow of a cooling / heating medium with decreasing distance between the first and second boundary. In this variant, the process is increased with increasing distance between the first and second boundary and throttled with decreasing distance. In this way, the pressure in the cooling surface is controlled so that decreasing pressure counteracts a further increase in the distance between the boundaries and vice versa. Of course, this variant is also with the above variant of a controlled feed can be combined.

Advantageously, an inventive cooling / heating element, if it is stackable. In this way, an accumulator can be built particularly simple.

It is advantageous in a cooling / heating element according to the invention, if it has a toothing at its intended for stacking interfaces. The gearing helps to reduce shear forces within the stack, d. H. transverse to the stack or to its edge, to transfer and thus stabilize it. If the toothing is asymmetrical, this can also prevent the cooling / heating elements are stacked upside down or twisted.

It is advantageous in a cooling / heating element according to the invention, if an inlet or outlet is provided, which cooperates in a stack with an inlet or outlet of an adjacent cooling / heating element. In this way, the inflows and outflows of the individual elements form an inlet and outlet, which can extend over the entire stack, without the need for a separate piping would be necessary. The assembly of the accumulator is thus particularly simple, especially when a seal is molded directly on the cooling / heating element. The seal can also be designed as a separate part. In both cases, both seals of the same material are possible from which also the cooling / heating element consists, as well as seals made of a different material.

Moreover, it is advantageous in the case of a cooling / heating element according to the invention if it comprises at least one channel cooled with a cooling medium for removing hot combustion gases from a cell. Overheating, overcharging or other improper use may lead to a "thermal runaway" as already mentioned. In order to prevent it from spreading to other cells, the channel cooled with a cooling medium is advantageously provided for removing hot combustion gases. In order to improve the heat dissipation, several channels can be provided.

Furthermore, the invention is achieved by a cooling medium, namely a cooling medium for a cooling / heating element, which is added to an antifreeze and / or a surfactant and / or a corrosion inhibitor.

In particular, by adding surfactants, the cooling medium gets a dirt and air bubbles releasing effect. As a result, dirt and air bubbles are dissolved in the cooling medium and removed from the capillaries of the cooling / heating elements. This air bubbles and dirt dissolving effect also allows the inflow and outflow can be arranged in a lying built-in accumulator on the bottom. The air bubbles can then not accumulate or settle in the higher areas of the cooling elements - these are washed out at a sufficient flow rate. The cooling effect thus remains uniform over the entire cooling surface.

In addition, the invention is achieved by a cell for a rechargeable battery, namely a cell for a rechargeable battery whose terminal lug is cranked so that it comes to rest on their terminal lug when stacked with another cell.

According to the invention, "left" and "right" cells are stacked on top of each other to obtain a desired total capacitance or voltage. The terminal lugs come to lie one above the other, so that the connection of the cells can be made without further connecting wires or connecting webs. The terminal lugs can therefore be directly soldered together, welded (eg by ultrasonic welding or ultrasonic compacting) or chemically reactive connected. The juxtaposition of cells, especially when connected in series, is thus particularly simple. If the cells are connected in parallel, additional connecting brackets may have to be provided (in small numbers). A complex design in bimetal can usually be omitted.

It is advantageous in a cell if it additionally comprises a connection lug for connecting a temperature and / or voltage sensor. In this way, a temperature and / or voltage sensor can be connected very easily.

Finally, the object of the invention is achieved by an accumulator, namely by an accumulator comprising a base element arranged in a stack, a cover element and at least one cooling / heating element between the base element and the cover element and at least a first and a second cell, which the cooling / heating element adjoin the interior of the stack.

A typical battery assembly usually requires multiple series connected cells to obtain a desired output voltage. Often, 100 and more cells are needed. For example, in the prior art, 12 cells can be assembled into one module and then 8 modules strung together to obtain a desired voltage. For the realization of different capacities and / or voltages of a rechargeable battery is according to the invention now proposed to provide a stack of cells (eg, 50 to 70 cells) with intervening cooling / heating elements. The production of an accumulator is thus particularly flexible, since one does not rely on modules with 12 cells and their multiples, but can also add or omit individual cells. Of course, an electronic circuit provided for monitoring the cells can also monitor smaller groups from the 50 to 70 cells, but these circuits are preferably combined in an electronic module.

It is advantageous in an accumulator according to the invention, when the medium is under pressure in the cooling / heating element. The cells of the accumulator do not necessarily have a rigid outer housing but are partially embedded only in relatively soft plastic sheaths. For this reason, the cells usually require an external pressure, typically up to 2 bar, for proper function.

It is advantageous in the case of an accumulator according to the invention if a fire-retardant material is arranged between a boundary of a cooling / heating element and a cell, in particular a refractory fleece, a refractory fabric or refractory paper. In the event of a defect or improper use of the accumulator, individual cells may "burn off", which, as a result of the great heat development, may also ignite the neighboring cells and thus cause destruction of the entire accumulator. To counteract this chain reaction, a fire-retarding layer is advantageously arranged between a cell and a cooling / heating element in such a way that the fire-retardant material degrades a large proportion of the temperature gradient up to the surface of the cooling element. This can prevent thermal damage to a cooling / heating element adjacent to a cell affected by the thermal runaway.

It is advantageous in the case of an accumulator according to the invention if the surface of the base element and / or cover element is curved outwardly, in particular with a central indentation. In this way, forces that are applied, for example, by a wound around the accumulator strap, are particularly well introduced into the accumulator. The indentation can advantageously serve to accommodate a turnbuckle.

It is advantageous in an accumulator according to the invention, if in the stack a control with an electronic control module is arranged, which is provided for controlling switching and / or measuring operations in the accumulator. Modern accumulators often include electronic circuits that serve to monitor and control the same. According to the invention, these control modules are integrated in one or more control elements, which can be arranged, for example, within a stack of cooling / heating elements. The construction of a rechargeable battery is therefore particularly simple.

It is advantageous in an accumulator according to the invention, when the control is adjacent to a cooling / heating element. In this way, the control or the control module contained therein can be cooled, which is particularly advantageous if the control module includes elements of the power electronics, which sometimes switch very high powers. This control module may include, for example, a recharger for the rechargeable battery.

It is also advantageous in the case of an accumulator according to the invention if a battery disconnect unit or battery disconnect unit and / or an accumulator management unit or battery management unit is provided as the control element. In this way, the two units frequently used in a rechargeable battery can easily be integrated into the rechargeable battery or also be cooled.

It is advantageous in an accumulator according to the invention, when the electrical connections of the individual elements of the accumulator lie substantially in one plane. In this way, the wiring of the accumulator or the review of the same - for example, when the accumulator is defective - particularly simple.

It is advantageous in an accumulator according to the invention, when all temperature and / or voltage sensors for monitoring the cells and / or circuit parts for balancing the cells are arranged on a circuit board. The structure of the circuit for checking the cells of the accumulator is thus particularly simple.

It is advantageous in an accumulator according to the invention, if temperature and / or voltage sensors for monitoring the cells and / or circuit parts for balancing the cells are arranged on different boards and between the boards a potential-free communication connection is provided. Here, individual boards are used to monitor a cell or group of cells, which accommodates the modular design of the battery. There is a voltage-potential-bridging communication link between the boards, so that the sometimes high potential differences within a cell stack are not detrimental or even destruction of the components on the individual boards can lead. Communication can be serial from board to board but also from any board to any other board. Also conceivable is a star-shaped communication to a central control unit. Of course, hybrids are also conceivable.

It is also advantageous in the case of an accumulator according to the invention if an optical data connection or a radio connection is provided as the potential-free communication connection. In this way, a voltage potential between the individual boards can be bridged particularly well. This technique can also be used independently of other features mentioned in the application, thus for each type of accumulator.

It is also advantageous in an accumulator according to the invention if the electrical connections of the individual elements of the accumulator are connected to a cell monitoring unit or a Cell Supervisory Cuircuit. In this way, this often used in a battery unit can be easily integrated into the accumulator.

It is advantageous in the case of an accumulator according to the invention if a strap is arranged around the stack. Since the stack is relatively unstable without further measures and usually no pressure can be built up within the accumulator, a tension band is placed around the accumulator according to the invention, which holds them together and, moreover, absorbs the internal pressure forces. Of course, several clamping bands can be placed around the accumulator. Tension straps to hold cells of a battery together are known per se. For example, the JP 2003323874A to an arrangement in which several cells are held together by a strained band. In contrast to the present invention, JP 2003323874A, however, varies the length of the stack and thus the length of the strip. In the present invention, however, the length of the outer band remains the same. Therefore, bands of materials with comparatively high modulus of elasticity can be used. Preferably, these bands are adjusted in terms of their thermal expansion coefficient of the thermal expansion properties of the stack.

It is advantageous in an accumulator according to the invention, when the clamping band consists of one of the materials: rubber, metal, plastic, fiber-reinforced plastic. For example, rubber offers the advantage that the band can be placed around the accumulator without further measures and builds up a force there. In contrast, metals are not so elastic and are advantageously tensioned and fixed with a device. But they can withstand much higher forces than rubber. Plastics offer a good middle ground.

It is advantageous in an accumulator according to the invention, when the clamping band has a turnbuckle. In this way, the bands can be well tensioned, especially those made of relatively high modulus materials.

It is advantageous in an accumulator according to the invention, if retaining tabs are provided, which are clamped between a clamping band and a base element or cover element. In order to be able to fix the accumulator in a vehicle or a device to be supplied with energy, holding tabs between clamping band and a basic element or cover element are advantageously clamped in this variant. In this way, the tabs can be particularly easily arranged at different positions or different retaining tabs for otherwise identical accumulators can be used. The accumulator can thus be adapted particularly well to different installation situations.

It is advantageous in an accumulator according to the invention, when over the stack vertically extending tension elements, in particular threaded rods, are provided, which are intended for the cohesion of the stack. Threaded rods which are arranged vertically (that is to say transversely to the parting plane of the individual modules) are likewise very well suited for stabilizing the stack or for absorbing internal pressures of the accumulator. By simply cutting to length, they can also be easily adapted to different levels of stacking. At the bottom and at the top of the stack is then clamped together with a nut.

It is advantageous in an accumulator according to the invention, when a horizontally extending over the stack bridge is provided, in particular of flat material, a U-profile or a tubular profile, which has at the ends elements for receiving the tension elements, in particular holes for receiving a threaded rod. If the accumulator has no holes for receiving a threaded rod or for better force distribution, a bridge can be provided horizontally (that is, in the direction of the separation plane of the individual modules) over the stack. An upper and a lower bridge are then in turn stretched by means of threaded rods and nut against each other and thus keep the stack together safely.

It is advantageous in an accumulator according to the invention, if retaining tabs are provided, which are clamped between a bridge and a base element or cover element. Also in this variant retaining tabs can be used. In this way, the tabs in turn can be easily arranged at different positions or different retaining tabs for otherwise identical accumulators can be used. The accumulator can thus be adapted particularly well to different installation situations.

The above embodiments and developments of the invention can be combined in any manner.

BRIEF DESCRIPTION OF THE FIGURES

The present invention will be explained in more detail with reference to the exemplary embodiments indicated in the schematic figures of the drawing. It shows:

1 a section of a stack of single cells with intermediate cooling / heating plate;

2 a further section of a stack of individual cells, each having a fold at its edge;

3 a cooling / heating element from above;

4 a plan view of a cooling / heating element with inserted or molded seal;

5 a section through a stack of a plurality of single cells with cooling / heating elements arranged therebetween;

6 a cooling / heating element with a flow aperture in the inlet of a cooling surface;

7 a variant of a cooling / heating element with an inlet panel and a drain panel;

8th a stack of two identical cooling / heating elements;

9 a cooling / heating element made of sheet metal;

10 Spring characteristics of various disc springs;

11 a volume balancing assembly with a flexible container;

12 a volume compensation arrangement with a rigid container;

13a a primitive from below;

13b a primitive from above;

14 a first embodiment of a cell;

15 a second embodiment of a cell;

16 an accumulator-disconnecting unit;

17 a half-finished Paketakkumulator in an oblique view;

18 a half-finished Paketakkumulator in front view;

19 an accumulator management unit;

20 a fuse module with additional current sensors and high-voltage plugs;

21 a finished Paketakkumulator in an oblique view;

22 the upper portion of a Paketakkumulators with mounting tabs;

23 a first variant of a channel for the removal of hot fuel gases;

24 a second variant of a channel for the removal of hot fuel gases.

DETAILED DESCRIPTION OF THE INVENTION

Cooling:

For optimum battery operation, the cells thereof are cooled or heated to maintain an optimum operating temperature. If the cells of an accumulator are flat, their temperature can be controlled by the comparatively large flat areas of the accumulator. This can be achieved, for example, by aluminum plates, which conduct the heat to the edge of the cell. Another possibility is plates or bags, which are traversed by a cooling medium. 1 shows a part of a stack 10 of single cells 11 , between each of which a cooling / heating plate 12 is arranged. The cooling / heating plate 12 has limitations 13 on, over flexible webs 14 connected to each other. In a concrete embodiment of such a stack 10 For cooling, a cooling water flow of approx. 3 g / s was provided, passing through a gap of approx. 0.2 mm inside the cooling / heating plate 12 flows. This results in a pressure drop of about 7 kPa. The same flow can also be used to heat the cells.

So that the cooling / heating plate 12 in thermally conductive connection to the cells 11 the entire cooling water circuit can be pressurized (eg inflated to approx. 2 bar). So that the pressing forces can act on the cell, the limits should be 13 the cooling / heating plate 12 have a freedom of movement. The limits 13 should therefore be connected only at the edge or have flexible webs. Since the pressing forces are transmitted directly to the cell, one needs for the limits 13 or walls only very thin material thicknesses such. B. 1 mm plastic or 0.2 mm sheet metal.

2 shows another section of a stack 20 of single cells 21 , which at their edge in each case a fold 22 exhibit. Advantageous is the room 23 between the cells 21 used for the supply and / or removal of a cooling medium (see also 3 and 5 ).

3 shows a cooling / heating element 30 from above. The cooling / heating element 30 includes an inlet 31 , a cooling surface 32 as well as a process 33 , Over the four side edges of the cooling surface 34 . 35 . 36 and 37 Various possibilities are conceivable, such as the cooling medium from the inlet 31 over the cooling surface 32 the end 33 can get. Representing are in the 3 two variants shown. In a first variant, a cooling / heating element 30a from left to right so from the side edge 34 to the side edge 36 traversed. In a second variant, a cooling / heating element 30b from bottom to top, so from the side edge 35 to the side edge 37 traversed. Of course, many other variants are conceivable, in particular a meandering arrangement of the cooling channels. The cooling / heating elements 30 . 30a . 30b can be stacked on top of each other, passing through the superimposed inflows 31 and drains 33 each results in a continuous supply and discharge. To ensure the tightness, seals can be provided, for example, from the material of the cooling / heating element 30 . 30a . 30b , a molded seal or an inlaid seal. Finally, the cooling / heating elements 30 . 30a . 30b (in groups) are glued together. As a concrete embodiment shows 4 a plan view of a cooling / heating element 40 with inserted or molded gasket 41 ,

5 shows a section AA through a stack 50 several single cells 51 with interposed cooling / heating elements 53 , The single cells 51 are like in 1 with a fold 52 Mistake. The cooling / heating elements 53 have an inlet 54 and a process 55 on. In a variant of the invention is the edge 56 of the cooling / heating element 53 so high that between the cells 51 a certain minimum distance can be ensured and the cooling surfaces 58 the cooling / heating elements 53 can not be over-compressed.

The cells 51 Namely, they can no longer be moved towards each other as soon as they fold 52 on the edge 56 or the inlet 54 or expiration 55 issue.

From the 5 also becomes clear how the between the cells 51 remaining space 57 through the inlets 54 and processes 55 can be used. Alternatively or additionally, spacers in a cooling surface 58 be integrated yourself. The spacers can in the limits only on one side or on both inner sides of the cooling / heating element 53 be integrated or even be realized for example by a separate component (not shown), for. As an inserted grid or mesh or flexible webs. The too 1 mentioned flexible webs 14 can be designed so that a certain residual gap width even at relatively high on the cooling / heating element 53 acting forces is ensured and the webs 14 thus also fulfill the spacer function. At the footbridges 14 out 1 This is guaranteed because the tabs of the webs 14 excessive force, and de facto can not be further compressed. Finally, the two boundaries of a cooling surface can also be designed such that one is rigid and the other is flexibly suspended. This will give a better, stable positioning of the cells 51 reached in the stack.

Fireproof insulation:

Overheating, overcharging or other improper use may result in a so-called "thermal runaway". The whole is in a cell 51 stored chemical and electrical energy implemented within 5 to 25 seconds. This creates locally very high temperatures of over 700 ° C, due to the desired high packing density of the cells 51 the two neighboring cells 51 in the same module (these modules are often made of approx. 12 cells) ignited. Are several modules arranged side by side in such a way that the fireball of the first passed cell 51 one or more cells 51 ignites the neighboring modules, creates a chain reaction.

In the case of a thermal runaways, the spread of the fire should spread to neighboring cells 51 in the cell stack 50 or else on neighboring cell stacks if possible prevented become. These are the cooling / heating elements 53 advantageously made of sheet metal. The existing water cooling can, if one to the cooling / heating elements 53 Connected circulation pump runs, dissipate the accumulating heat energy. To the heat load on the cooling / heating elements 53 Nevertheless, to keep as low as possible, can be between the cells 51 and the cooling / heating elements 53 a refractory tile (heat-resistant, flame-retardant or refractory tissue or paper - not shown) to be inserted. This acts as an additional thermal insulation against very high temperatures and thus reduces the heat transfer from the burning cell 51 to the cooling / heating element 53 to a bearable level. So the fire on this one cell 51 be limited. In normal operation, due to the very low thermal performance (only about 1% of the thermal runaway) compared to the thermal runaway, there is no or no significant restriction in heat transfer from the cell 51 to the cooling / heating element 53 ,

The heat-resistant, flame-retardant or refractory layer can be dimensioned the thinner, the lower their thermal conductivity. Under normal conditions, that is from the cell 51 heat output less than 0.2 kW / m2 transferred to the cooling system causes a temperature drop of approx. 2 ° C at the said layer. In the case of a thermal runaways, a heat output of up to 20 kW / m2 may occur, causing a desired high temperature drop of around 200 ° C at this layer. The cooling water next to the burning cell 51 is heated to 100 ° C - through the cooling circuit, this energy is then evenly distributed over the entire mass of the battery without thereby reaching critical temperature values.

The removal of the hot fuel gases can be done via cooled with a cooling medium channels laterally in the cooling / heating elements 53 are integrated (not shown - see also the 23 and 24 ).

Flow in the cooling surface:

As the gap in the cooling surface increases, more cooling medium flows through this gap or capillary than through tight capillaries. This leads to an undesirable uneven heat dissipation or supply. This effect can be counteracted by providing a flow restrictor with a constant, independent of the movement of the boundaries of the cooling / heating surface, cross-section. This is preferably integrated on the inlet side. 6 shows a cooling / heating element 60 with a feed 61 , a cooling surface 62 and a process 63 , Furthermore, the cooling / heating element comprises 60 a flow aperture 64 which has an opening with a cross-section which is independent of the gap thickness in the cooling surface 62 remains essentially constant. 6 shows a cooling / heating element 60a with reduced cross-section and a cooling / heating element 60b with extended cross-section. Clearly seen is that the opening of the flow aperture 64 and thus the flow of the cooling medium through the cooling surface 62 remains essentially the same.

7 shows a further variant of a cooling / heating element 70 with a feed 71 a cooling surface 72 , a process 73 , a supply panel 74 and a progress bar 75 , When the gap thickness of the cooling surface 72 decreases, then the inlet aperture 74 continue to open and the drain panel 75 further closed (see cooling / heating element 70a ). When the gap thickness of the cooling surface 72 enlarged, then the inlet aperture 74 narrowed and the drainpipe 75 expanded (see cooling / heating element 70b ). In this way it is achieved that in a relatively narrow gap a relatively high pressure prevails, since the pressure reduction so only at the drain plate 75 he follows. The high pressure causes mm but that the gap thickness in the cooling / heating element 70 increased. At a relatively wide gap, however, the pressure is already at the inlet aperture 74 degraded, so that there is a relatively low pressure in the gap itself. The low pressure now causes the gap thickness in the cooling / heating element 70 reduced. As it were, there is a hydraulic regulation of the gap thicknesses of the individual cooling / heating elements arranged in a cell stack 70 ,

gearing:

8th shows a stack 80 of two identical cooling / heating elements 81 (executed here in plastic). Each cooling / heating element 81 includes an inlet 82 , a cooling surface 83 and a process 84 , For a better cohesion of the pile 80 Each cooling / heating element also has a toothing 85 on, the slipping of the cooling / heating elements 81 in the pile 80 prevented. Preferably, the toothing 85 Transmit shear forces in each direction. It can be arranged offset one or more rows. Furthermore, the gearing 85 in a particularly advantageous embodiment selbstverrastend (insoluble or detachable) executed. This simplifies assembly, especially if the individual cooling / heating element are glued together, since so a pressing against each other of the parts can be omitted by curing the adhesive by a separate device. The locking can z. B. be executed trapezoidal. The toothing is preferred 85 Meandered to avoid notch effects. In the 8th In each case only one tooth flank per side is executed. Advantageously, however, many tooth flanks are executed on each side. For example, the teeth are 2-5 mm wide. Finally, includes a cooling / heating element 81 also a fastening strap 86 for a cell monitoring circuit (see also 18 ). Advantageously, the fastening straps comprise 86 Fastening latches and coding ribs for correctly positioning the cell monitoring circuits along the cooling / heating elements 81 on.

In a specific embodiment, the cooling / heating elements 81 made of plastic, the wall thickness was about 1.5-2 mm at the edge, about 0.6 mm at the bottom of the tub. The material is durable with 6-7 N / mm2 at -40C to 85 ° C or durable and tight for water and / or glycol at 2 bar and a temperature of -40C to 85 ° C. Advantageously, the plastic should resist for a short time and once even higher temperatures of over 200 ° C.

9 shows an alternative cooling / heating element 90 , which is made of sheet metal (deep-drawn). For stacking the individual cooling / heating elements 90 this also includes a seal 91 , In a specific embodiment, the upper area was made of 0.6 mm, the trough area of 0.2 mm thick material. Preferably, the sheet is anti-corrosion coated.

Cooling medium:

Advantageously, the cooling medium has a high specific heat capacity, is frost-protected, is not corrosive to the materials used, has a low surface tension and is soil-releasing (dirt in this context also means dissolved gases or gas bubbles). These properties can also be achieved by adding suitable substances (eg antifreeze, surfactant, anticorrosion agents, etc.) to one or more basic substances. Since the cell stack is floatingly mounted in the arrangements shown, that is to say "floating" in the cooling medium, the cells are protected against shocks and high accelerations. For this purpose, the cooling medium preferably has a high density or is placed under a correspondingly high pressure. The cooling medium is advantageously liquid, but may of course also be gaseous.

Volume compensation:

Since the thickness of a cell has tolerances and this periodically changes during loading or unloading, a container for volume compensation is advantageous. Moreover, it is advantageous if a container for collecting the gas bubbles contained in the cooling medium is provided. This can be two different containers or one and the same container. For the cells to be under a uniform pressure, the entire cooling system is pressurized. This can be done before each operation of the cells via a small pump, which pushes the cooling medium from a reservoir into the cooling / heating elements, or the entire system is factory-set under pressure after assembly. So that the pressure does not change as far as possible in the event of temperature fluctuations or changes in the charge of the cells (this does not change the thickness of the cells), the volume compensation vessel is advantageously under mechanical pressure, which is preferably realized with the aid of disc springs. Disc springs allow a suitable choice of the spring characteristic, which generates an approximately constant force over a larger stroke. 10 shows spring characteristics 100 different disc springs. The force F is plotted over the path s. The disc springs differ by different ratios of material thickness to the height of the plate spring. By a suitable choice, a force F which is nearly constant over a longer path can now be achieved. In the lower right diagram is an advantageous characteristic area 101 drawn, which ranges from about 25% to 90% of the spring travel s.

11 now shows a first variant of a volume compensation arrangement 110 consisting of a flexible container 111 and several disc springs 112 which gives a more or less constant force to the container 111 exercise. In the front area of the container 111 there is an opening 113 over which the container 111 can be connected to the cooling circuit.

12 shows a second variant of a volume compensation arrangement 120 consisting of a rigid container 121 with an opening 122 for connection to the cooling circuit. In the container 121 is a flexible container 123 arranged, over disc springs 124 a pressure on the container 121 contained liquid exerts. It is also conceivable, of course, instead of the flexible container 123 to provide a piston on which the disc springs 124 Act. In a specific embodiment, the volume expansion tank was designed with a diameter of 65 mm and a length of 220 mm, which results in a volume of about 730 cm ³ . The container is pressure-resistant for a nominal pressure of approx. 2 bar. Approximately 100 disc springs with a diameter of 25 mm, a height of 1.4 mm and a material thickness of 1 mm were provided for the pressure generation. The disc springs can be made of metal or plastic. The flexible container 123 was finally made with a diameter of 63 mm and a length of 150 mm and is made of sheet metal.

Basic Element:

The 13a and 13b show a primitive 130 from underneath ( 13a ) and from above ( 13b ). When assembled, the in 13a visible area outside and in 13b visible rib structure inside. The basic element 130 , which has a surface outside, which is curved for proper distribution of force, is used to build the (package) accumulator. Advantageously, the surface is curved in such a way that later used clamping bands for the assembly cause a uniform force distribution on the base. So that the tensioning strap can be tensioned and tensioning locks can be accommodated to connect the ends of the tensioning strap, the surface in the middle is concavely arched. Here too, an even force is applied to the surface. The surface is curved in the illustrated embodiment only in one direction. In a further embodiment, however, the surface may also be curved in both directions, resulting in a 3D curvature. From the surface, the forces are guided by ribs positioned directly above the straps to the lowest cooling / heating element. In order that the force distribution to the surface of the lowermost cooling / heating element is uniform, an additional, intermediate rigid plate is advantageous. In one variant, the cover element is the same or substantially the same as the base element 130 built up.

Connections of the cells:

14 shows a first embodiment of a cell 140 with a positive connection 141 and a negative connection 142 , via which the electrical power is supplied and removed. In addition, there are branches 143 present, via which an electronic circuit for monitoring the cell 140 can be connected. The branches 143 can be designed as planar contacts for a later conductive bonding or plug pins. For the connection of several cells 140 are the connections 141 and 142 bent or cranked executed. The positive connection 141 is here in the 14 up, the negative connection 142 bent down.

So that the cells 140 Without intermediate elements can be connected directly to each other two bending variants are required - a "left" and a "right" variant. 15 shows a cell 150 , the mirror image of the cell 140 out 14 is designed. The cell 150 analogously includes a positive connection 151 and a negative connection 152 , via which the electrical power is supplied and removed. The positive connection 151 is up, the negative connection 152 bent down. In addition, in turn, branches 153 present, via which an electronic circuit for monitoring the cell 150 can be connected.

In the example shown, the branches are 143 and 153 both at the positive terminals 141 and 151 as well as the negative connections 142 and 152 arranged. In the assembled state, that is after stacking the cells 140 and 150 , are thus twice as many branches 143 and 153 available as would actually be required. In an alternative embodiment, the branches are 143 and 153 therefore only with the positive connections 141 and 151 or only with the negative connections 142 and 152 arranged (applies to series connection of the cells 140 and 150 ).

The connection of the cells 140 and 150 can now be done without further elements, for example by welding, in particular ultrasonic welding or ultrasonic compacting, or by chemically reactive compound. The cells 140 and 150 are intended for series connection. For a parallel connection other bending variants would be provided. The parallel connection of several modules (ie several series connected cells 140 and 150 ) can also be made over longer connections or with the help of separate bridge plates (eg made of aluminum or copper).

Construction of a package battery

Starting from the basic element 130 out 13a and 13b , optionally an additional rigid plate for more even distribution of forces are alternately a cooling / heating element 81 out 8th , a cell 140 out 14 , another cooling / heating element 81 and a cell 150 out 15 stacked. Depending on your needs, this sequence of cooling / heating element 81 , Cell 140 , Cooling / heating element 81 and cell 150 be repeated as often as you like. The stack obtained is without further action by the teeth on the edge of the cooling / heating element 81 stable (see also 17 ). In experiments, stacks of about 1 m in height could be built easily. Advantageously, however, groups of cooling / heating elements 81 (and cells 140 . 150 ) are glued together, in particular are glued tight. Preferably, such modules are made in an upstream assembly step, so that in the final assembly of the package batteries only a few modules must be stacked on each other.

Battery Disconnect Unit

16 shows an accumulator-separation unit 160 , Clearly visible are the reinforcing ribs in the interior of the accumulator-separating unit 160 . which provide for a power transmission between the upper and lower joint surface. The electrical function of the accumulator-separation unit 160 is known per se. The accumulator-separation unit 160 is intended to galvanically isolate the high voltage circuit from the vehicle or other equipment connected to it by means of relays. Furthermore, the accumulator-separation unit comprises 160 a pre-charge circuit, which establishes an ohmic connection between the accumulator and the vehicle before the actual switching of the relays in order to be able to compensate for potential differences. Finally, the accumulator-separator unit includes 160 in the illustrated variant, current sensors and voltage sensors for measurements in the high voltage range and for monitoring the relay function.

17 shows a half-finished packet accumulator 170 consisting of the previously obtained stack 171 and a battery-separating unit mounted thereon 172 , Good to see is the gearing 173 the individual cooling / heating elements as well as the connected contacts 174 the individual cells. The accumulator-separation unit 172 also has a cooling channel 175 on, so that the cooling medium of the under the accumulator-separating unit 172 arranged cooling / heating element in the accumulator-separation unit 172 can flow (in the 17 are the better Vorbarbarkeit half the axes of the cooling channels shown). For stiffening points the accumulator-separation unit 172 Moreover, reinforcing ribs 176 to forward the sometimes high forces within the stack. All electrical connections (both high voltage and low voltage) are advantageous in one connection plane 177 arranged, whereby a particularly simple electrical connection technology can be applied.

Cell supervision unit (Cell Supervisor Circuit)

18 shows a half-finished packet accumulator 180 , consisting of stacked cooling / heating elements 181 , an accumulator-separating unit mounted thereon 182 and other cooling / heating elements 181 , An area 183 indicates where later a cell monitoring unit will be located. The cell monitoring unit is positioned directly between cell terminals. This area is bordered by webs of the cooling / heating element. These webs, provided with suitable detents form the holder of the cell monitoring unit and advantageously contain elements which enable coding or secure positioning of the cell monitoring unit over the lateral cell branches. These cell branches are designed for conductive splices or directly for plugging. Any sticking of the cell monitoring unit to the cell branches can be done by large vias in the board of the cell monitoring unit. If the cell branches are kept very short, then there is a good thermal connection to the cell body, whereby the sensors for temperature measurement can be positioned directly on the board of the cell monitoring unit, but in the vicinity of the cell branches. This can be a part of the low-voltage wiring including the connector to the cells, as required in conventional systems, omitted. Due to the small distance between the individual cell monitoring units to each other, an arrangement of several cell monitoring units on a single (here elongated) board is conceivable. The maximum length is limited in itself only by the thermal expansion properties of the cooling / heating element and the boards or the maximum producible board lengths. Essentially, the cell monitoring unit serves to measure the voltage and / or temperatures of the cells, to enable the balancing of the cells, and to ensure the communication between different cell monitoring units. Advantageously, the connection between several cell monitoring units via a connection bridging a voltage potential, to avoid problems due to sometimes high potential differences (a stack of cells can produce several hundred volts of voltage). For example, the cell monitoring units may be connected by optical means or by radio. Communication in both cases can be done serially from cell monitoring unit to cell monitoring unit but also from each cell monitoring unit to any other cell monitoring unit. Also conceivable is a star-shaped communication to a central control unit. Of course, hybrids are also conceivable.

Accumulator Management Unit (Battery Management Unit)

19 shows an accumulator management unit 190 (shown here with an open housing). The accumulator management unit 190 is essentially intended to control the processes in the accumulator and to allow communication with the vehicle or other device connected to the accumulator. In the illustrated variant, the accumulator management unit comprises 190 plus two processors, which control, for example, measuring processes, control relays for disconnecting the battery from the consumer, etc.

The accumulator management unit 190 (Shown here without covering the electronics) forms the upper end element of the package battery and is designed like the basic element above arched. The surface is advantageous in this way arched, that later used clamping bands for the assembly cause a uniform force distribution on the base. So that the tensioning strap can be tensioned and tensioning locks can be used to connect the ends of the tensioning strap, the surface is concave in the middle. Here too, an even force is applied to the surface. The surface is curved in the illustrated embodiment only in one direction. In a further embodiment, however, the surface may also be curved in both directions, resulting in a 3D curvature. From the surface, the forces of ribs positioned directly under the straps become that under the accumulator management unit 190 lying element out. In order for the force distribution to this element is uniform, an additional, intermediate rigid plate is advantageous. This is preferably under the accumulator management unit 190 lying element a cooling / heating element (eg as well as out 8th known). Via webs or ribs in the housing of the accumulator management unit 190 an electronic circuit of the same or its board is pressed against the cooling / heating element, so that an optimal heat transfer can take place. In particular, the accumulator management unit 190 as well as power circuits included. The external port of the accumulator management unit 190 can be done via a connector strip, which are advantageously in the same plane as other contacts of the accumulator (namely in the connection plane 177 out 17 ). Advantageously, the power strip of the accumulator management unit 190 used directly for the low-voltage connection of the Paketakkumulators and has for this purpose at least one connector chamber (not shown), which lies in said plane to allow the internal low-voltage connections. Although the accumulator management unit 190 as in 19 shown advantageously located at the top of the Paketakkumulators, this can of course also be designed as a lying inside the Paketakkus module.

Module with current sensor, fuse and high-voltage plug

20 shows a fuse module 200 (pictured here without the associated electronics), which additionally includes current sensors and high-voltage connectors. In the case of a distributed system (that is to say an association of a plurality of packet accumulators), an identical security module advantageously becomes available in each of the individual packet accumulators 200 installed in order to be able to separately protect each Paketakkumulator in the event of a short circuit. The current sensor can also be accommodated in another module (in particular in the in 16 illustrated accumulator-separation unit).

Straps:

21 now shows a finished Paketakkumulator 210 consisting of a basic element 211 , several cooling / heating elements 212 with internal cells (not shown), an accumulator-separation unit 213 , another cooling / heating element 214 , a security module 215 additionally comprising current sensors and high-voltage connectors, another cooling / heating element 216 and an accumulator management unit 217 , In the example shown, the entire arrangement is made by tension bands 218 (here by 4 tension bands 218 ) held together. For clamping, the tension straps 218 Turnbuckles on, which are advantageous under the basic element 211 or above the accumulator management unit 217 be guided.

The straps can be made of rubber, steel, plastic or fiber-reinforced plastic. The choice of material depends on the forces to be transmitted and on the thermal expansion properties of the bands and the module composite, that is to say the tension bands 218 should be matched in terms of their elongation properties on the expansion behavior of the module composite. The tension bands 218 transfer the pressing forces of the cells from the basic element 211 to the upper end plate (here in the form of the accumulator management unit 217 ). In addition, forces are transmitted through the toothed edges of the cooling / heating element 212 . 214 and 216 act and give the only mated module composite a bias or the required stability.

The outer edges of the individual components form a strong, preloaded, solid housing for the accumulator. The boundaries or walls of the cooling surfaces of the cooling / heating elements 212 . 214 and 216 (see also 5 ) form an internal stiffening of the housing. With usual numbers of approximately 50 cells for a packet accumulator 210 There are 100 walls (2 per cell) across the accumulator 210 so that an extremely stiff but still lightweight housing is created, similar to a stiffened by bulkheads or ribs ship or aircraft fuselage.

The tension bands 218 can be embedded or recessed into the surface on the circumference of the housing for protection (recess in the surface of the module assembly). For ease of illustration, a cover has been placed on the front of the accumulator 210 , which takes over the task of contact protection and sealing, not yet appropriate.

The length of the tension bands 218 can be changed very easily, so that from the individual components very easily many different types of package accumulators 210 can be made. Nevertheless, of course, other mounting options are conceivable. For example, the accumulator can be screwed. Especially suitable here are threaded rods whose length can also be easily adapted to different conditions. These threaded rods are pushed through holes in the modules, for example. The attachment is then by mother. It is also conceivable that above and below the Paketakkumulators 210 Bridges are provided, which have at their ends holes for said threaded rods and so the Paketakkumulator 210 stick together.

Attachment points of the package accumulator:

In order to mount the package accumulator in a vehicle or other powered device, suitable attachment points on the package accumulator are required. 22 for this purpose shows the upper area of a packet accumulator 220 namely a lid 221 to make a strap 222 with a turnbuckle 223 is laid. Between lid 221 and strap 222 are fastening straps 224 inserted, which is the attachment of the Paketakkumulators 220 in allow for example a vehicle. Advantageously, the lid 221 and / or the tabs 224 to a toothing 225 which prevent or at least reduce mutual slippage. Of course, it is also possible, additionally or alternatively tabs on the underside of the Paketakkumulators 220 provided. It is also conceivable, of course, that the tabs are part of the bottom or lid of the Paketakkumulators 220 are attached or otherwise attached, for example by screwing. In particular, the tabs 224 between lids 221 and to 21 be arranged bridges mentioned.

Removal of hot fuel gases:

23 shows another section of a stack 230 of single cells 231 , which at their edge in each case a fold 232 which is the stack 20 out 2 is very similar. Again the room becomes 233 between the cells 231 used for the supply and / or removal of a cooling medium. In this variant, but is an additional cooled with a cooling medium channel 234 intended for the removal of hot fuel gases.

24 shows a section through a stack 240 several single cells 241 with interposed cooling / heating elements 243 which is the pile 50 out 5 is very similar. The single cells 241 are in turn with a fold 242 Mistake. In this variant is also an additional cooled with a cooling medium channel 244 intended for the removal of hot fuel gases. So that the fuel gases in the channel 244 can escape between the front of the fold 242 and the channel 244 in the edge of the cooling / heating elements 243 Provided openings. For example, the edge of the cooling / heating elements 243 crenellated. In 24 are further connection channels 245 to the cooling / heating elements 243 intended. However, this is only an example to see, of course, other embodiments of the cooling / heating elements 243 and the channel 244 conceivable. It is also conceivable that the channels of the cooling / heating elements 243 and the channel 244 not separated, but executed together.

Finally, it is noted that the representations in the figures are sometimes not true to scale. Furthermore, the individual variants shown in the figures can also form the subject of an independent invention.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2003323874A [0044]

Claims (2)

Volume compensation arrangement ( 110 ) for a cooling / heating medium of an accumulator ( 170 . 180 . 210 ) comprising a flexible housing ( 111 ) to which a prestressed elastic element ( 112 ) acts or comprises a rigid housing ( 121 ), in which a flexible housing ( 123 ) to which a prestressed elastic element ( 124 ) acts. Volume compensation arrangement ( 110 . 120 ) according to claim 1, characterized in that the elastic element ( 112 . 124 ) in one area ( 101 ) is operated, in which the force (F) is substantially independent of the spring travel (s).

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