ENERGY STORAGE DEVICE FOR A MOTOR VEHICLE AND METHOD FOR COUNTERACTING A FIRE OF AN ENERGY STORAGE DEVICE

Abstract

An energy storage device for a motor vehicle includes a battery module and at least one thermally insulating filling element, which is preferably designed as a thermally insulating cell separator element arranged between two battery cells of the battery module. The filling element is designed to be soluble here, so that it dissolves at least in part when it comes into contact with a specific minimum amount of a specific liquid.

Claims

1. An energy storage device for a motor vehicle, wherein the energy storage device includes a battery module and at least one thermally insulating filling element, wherein the filling element is designed to be soluble, so that it dissolves at least in part when it comes into contact with a specific minimum amount of a specific liquid.

2. The energy storage device according to claim 1, wherein the battery module includes at least two battery cells arranged adjacent to one another in a first direction, wherein the filling element is designed as a thermally insulating cell separator element arranged between the two battery cells.

3. The energy storage device according to claim 1, wherein the filling element is designed in such a way that it does not dissolve or does not completely dissolve on contact with the specific liquid below the specific minimum amount.

4. The energy storage device according to claim 1, wherein the filling element is designed to absorb and in particular bind a certain amount of the specified liquid, in particular below the specified minimum amount.

5. The energy storage device according to claim 1, wherein the specific liquid is water.

6. The energy storage device according to claim 1, wherein the filling element comprises a hydrophilic aerogel and is in particular formed completely from a hydrophilic aerogel.

7. The energy storage device according to claim 1, wherein the filling element is designed to be soluble such that it dissolves at least in part when it comes into contact with the specific liquid.

8. The energy storage device according to claim 1, wherein the battery module includes multiple filling elements designed as cell separator elements and numerous battery cells arranged adjacent to one another in the first direction, wherein one of the cell separator elements is arranged between each two battery cells arranged adjacent in the first direction.

9. The energy storage device according to claim 1, wherein the energy storage device includes an intermediate space which is not located between two battery cells of the same battery module and which is arranged in particular outside of the cell stack formed by the battery cells of the battery module, wherein the filling element is arranged in the intermediate space.

10. A method for counteracting a fire of an energy storage device for a motor vehicle, which includes at least one battery module and a thermally insulating filling element, wherein to counteract the fire, a specific liquid is supplied to the energy storage device, wherein the filling element dissolves at least in part upon contact with a specific minimum quantity of the specific liquid.

11. The energy storage device according to claim 2, wherein the filling element is designed in such a way that it does not dissolve or does not completely dissolve on contact with the specific liquid below the specific minimum amount.

12. The energy storage device according to claim 2, wherein the filling element is designed to absorb and in particular bind a certain amount of the specified liquid, in particular below the specified minimum amount.

13. The energy storage device according to claim 3, wherein the filling element is designed to absorb and in particular bind a certain amount of the specified liquid, in particular below the specified minimum amount.

14. The energy storage device according to claim 2, wherein the specific liquid is water.

15. The energy storage device according to claim 3, wherein the specific liquid is water.

16. The energy storage device according to claim 4, wherein the specific liquid is water.

17. The energy storage device according to claim 2, wherein the filling element comprises a hydrophilic aerogel and is in particular formed completely from a hydrophilic aerogel.

18. The energy storage device according to claim 3, wherein the filling element comprises a hydrophilic aerogel and is in particular formed completely from a hydrophilic aerogel.

19. The energy storage device according to claim 4, wherein the filling element comprises a hydrophilic aerogel and is in particular formed completely from a hydrophilic aerogel.

20. The energy storage device according to claim 5, wherein the filling element comprises a hydrophilic aerogel and is in particular formed completely from a hydrophilic aerogel.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0031] Exemplary embodiments of the invention are described hereinafter. In the figures:

[0032] FIG. 1 shows a schematic representation of a high-voltage battery having multiple battery modules according to an exemplary embodiment of the invention;

[0033] FIG. 2 shows a schematic representation of a part of the high-voltage battery of FIG. 1 according to an exemplary embodiment of the invention;

[0034] FIG. 3 shows a schematic representation of the high-voltage battery of FIG. 1 in case of a module fire according to an exemplary embodiment of the invention; and

[0035] FIG. 4 shows a schematic representation of part of the high-voltage battery of FIG. 3 during or after the supply of extinguishing water to extinguish the fire according to an exemplary embodiment of the invention.

DETAILED DESCRIPTION

[0036] The exemplary embodiments explained hereinafter are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual features of the invention to be considered independently of one another, which each also develop the invention independently of one another. Therefore, the disclosure is also intended to comprise combinations of the features of the embodiments other than those represented. Furthermore, the described embodiments can also be supplemented by further ones of the above-described features of the invention.

[0037] In the figures, same reference numerals respectively designate elements that have the same function.

[0038] FIG. 1 shows a schematic representation of a high-voltage battery 10 as an example of an energy storage device 10, having multiple battery modules 12 according to an exemplary embodiment of the invention. The high-voltage battery 10 generally includes a battery housing 14 which provides a respective receiving area 16 for each battery module 12. The receiving areas 16 can be spatially separated from one another, for example by partition walls 18, but this does not necessarily have to be the case. A respective battery module 12 in turn includes multiple battery cells 20 which are arranged adjacent to one another in the x-direction in this example. For reasons of clarity, only a few of the battery cells 20 are provided with a reference sign. In this example, the battery cells 20 are designed as prismatic battery cells, but can generally also be designed differently. In this example, there is a filling element 22 in the form of a cell separator element 22 between each two battery cells arranged adjacent in the stacking direction X of a respective battery module 12. Here as well, only a few of these cell separator elements 22 are provided with a reference number for reasons of clarity. These cell separator elements 22 are manufactured from an NTP (No thermal propagation) material, which is provided by a hydrophilic aerogel 24 in this preferred example. This advantageously makes it possible to equip the cell separator elements 22 with particularly advantageous properties. The cell separator elements 22 are designed in such a way that when they are not in contact with a specific liquid, in particular water, they are in a dimensionally stable state, as illustrated in FIG. 1 and FIG. 2. FIG. 2 shows in particular an enlarged detailed view of a part A of the energy storage device 10 from FIG. 1. In this dimensionally stable state of the cell separator elements 22, they have very good thermally insulating properties, since they have a very porous structure due to the formation of a hydrophilic aerogel 24 possess and consist accordingly to a large extent of air or gas in general. As a result, a very good thermal barrier to the adjacent battery cells 20 can be provided by the cell separator elements 22 in the event of a thermal runaway of one of the battery cells 20. A thermal spread to an adjacent battery cell 20 can thus be prevented particularly efficiently. It can be advantageous to provide such thermal insulation not only in the form of cell separator elements 22 between the cells 20, but also, for example, as corresponding filling elements 26 at another point, such as here, for example, surrounding the respective cell stack of the multiple battery cells 20 of a respective battery module 12 In this way, the battery modules 12 can also be thermally insulated to the outside and from one another. These filling elements 26 can be designed having the same properties as the cell separator elements 22 and in particular can also be manufactured from the same material 24. Correspondingly, these filling elements 26 are also preferably provided by a hydrophilic aerogel 24. The following descriptions of the cell separator elements 22 therefore also apply in the same way to these further filling elements 26.

[0039] Despite the good thermal insulation between the cells 20, thermal runaway of several of the battery cells 20 can occur simultaneously, for example in the event of a crash or accident of the motor vehicle which comprises this high-voltage battery 10. As a result, under certain circumstances, a battery fire 30 can occur, as is shown schematically in FIG. 3 and in FIG. 4. FIG. 3 again shows the high-voltage battery 10 from FIG. 1, but now in case of a fire, in which multiple battery cells 20 have caught fire, and FIG. 4 again shows a schematic detailed view of a detail A of the high-voltage battery from FIG. 3.

[0040] It has proven most effective for firefighting to supply an extinguishing agent, such as water 32 in this example, to the battery 10 or the relevant battery module 12 and to have this water 32 flow around the battery cells 20 accordingly. In order to enable flow through, the battery 10 can moreover also include a suitable drain, for example in the housing 14.

[0041] With conventional batteries, however, there is the problem that the filling of any spaces with thermally insulating material has the result that, in case of flooding, there is no longer any free space available to enable efficient flow around the battery cells. Efficient extinguishing of a battery fire is therefore not possible in conventional batteries, or at least not in a space-saving manner, because otherwise free spaces through which a flow can flow have to be reserved, which requires additional installation space.

[0042] The cell separator elements 22, as well as the other filling elements 26, are now advantageously designed in such a way that they at least partially dissolve upon contact with water or at least upon contact with a specific minimum amount of water. It is particularly preferred that the cell separator elements 22 initially do not dissolve upon contact with a small amount of water, in particular less than the predetermined minimum amount, but instead soak up or absorb the water 32 and thereby bind it and swell up themselves. Only when the maximum possible amount of water has been absorbed by the cell separator elements 22 and these are saturated, so to speak, do they dissolve when the water is supplied further and are flushed out of the spaces 34 by the supplied water 32. The same also applies to the filling elements 26, which are then correspondingly flushed out of the free space 36 in which they are arranged.

[0043] FIG. 4 correspondingly shows a state of part of the energy storage device 10 in which the cell separator elements 22 and the filling elements 26 have already been dissolved and the supplied water 32 accordingly washes around the battery cells 20. This enables particularly efficient fire extinguishing and firefighting.

[0044] The fire protection material 24 described is thus located between the cells 20 or between the cell modules 12 in the form of the cell separator elements 22 or filling elements 26, which has the focus of having the lowest possible thermal conductivity. This material 24 ensures No Thermal Propagation, thus preventing thermal propagation across all battery cells 20 when one of the battery cells runs away 20 thermally. Due to the hydrophilic design of this NTP material 24, for example in the form of hydrophilic aerogels 24, good thermal insulation in the undissolved state of this material 24 can be provided at the same time, as well as water solubility at the same time. This makes it possible for the material 24, in particular in the form of the cell separator elements 22 and the filling elements 26, to be flushed out of the housing 14 by water 32. As a result, additional flow cross sections are uncovered. In addition, this material can provide 24 superabsorbent properties. With small amounts of water, the material 24 from which the cell separator elements 22 and the filling elements 26 are formed can be swollen analogously to a super absorber. This has the result that the water 32 absorbed by the cell separators 26 remains in place around the burning cell 20, requiring a great deal of energy to evaporate the amount of water absorbed by the cell separator 22. In principle, one of the following combinations of properties can be provided by the cell separator elements 22 or filling elements 26: thermal insulation and water solubility, thermal insulation and superabsorber property, thermal insulation and water solubility and superabsorber property. However, the implementation of the water-soluble properties is particularly advantageous here.

[0045] Because the cell separator elements 22 have superabsorbent properties, a two-stage extinguishing method can be implemented in a particularly advantageous manner. This enables water inside the vehicle, for example wiper water or cooling water, to be routed locally to the area of the burning cells 20 in a first extinguishing step. Due to the superabsorber properties, the water 32 is absorbed by the NTP material 24, in this case the hydrophilic aerogel 24, and held around the cells 20 permanently. The evaporation of the water requires a correspondingly large amount of energy and has prevented the fire 30 from spreading to other cells 20 in preliminary tests.

[0046] In a next step, for example, a fire department would now be on location and could flush the hydrophilic fire protection material 24 out of the housing 14 using the large amount of extinguishing agent carried along, in particular water 32, which in turn would open up the flow cross sections in the high-voltage battery 10. With this measure at the latest, a burning electric vehicle can be extinguished even after excessive loads.

[0047] Overall, the examples show how the invention can be used to provide hydrophilic aerogels as intermediate cell material for fulfilling NTP and for active flushing in case of extinguishing. This allows extinguishing from the outside using water while maintaining the NTP fire protection measures, namely thermal insulation. In this way, no additional space is required to create the necessary flow cross-sections and a synergetic, space-neutral introduction of super absorbers is also implementable.