DEGASSING CHANNEL, BATTERY ASSEMBLY, AND MOTOR VEHICLE

Abstract

A degassing channel for a battery in a motor vehicle designed to be arranged on a cell pack of the battery, which cell pack includes at least one battery cell, which has a releasable cell-degassing opening. The degassing channel has a first channel wall with a releasable wall opening that is assigned only to the cell-degassing opening, which wall opening can be released by a gas pressure of a gas escaping from the assigned cell-degassing opening when the degassing channel is arranged on the cell pack, so that the escaping gas can be directed through the released wall opening into an interior of the degassing channel.

Claims

1. A degassing channel for a battery in a motor vehicle, wherein the degassing channel is designed to be arranged on a cell pack of the battery, which cell pack comprises at least one battery cell, which comprises a releasable cell-degassing opening, wherein the degassing channel has a first channel wall with a releasable wall opening that is assigned only to the cell-degassing opening, which wall opening can be released by a gas pressure of a gas escaping from the assigned cell-degassing opening when the degassing channel is arranged on the cell pack, so that the escaping gas can be directed through the released wall opening into an interior of the degassing channel.

2. The degassing channel according to claim 1, wherein the first channel wall represents a cooling base for cooling the cell pack.

3. The degassing channel according to claim 1, wherein the degassing channel has a second channel wall opposite the first, which is provided by an underride guard.

4. The degassing channel according to claim 1, wherein the first channel wall has a material weakening in the region of the releasable wall opening to provide a predetermined breaking point for releasing the wall opening, which predetermined breaking point is designed as an engraving on a side of the first channel wall that faces toward or faces away from the second channel wall, and which is provided along a fully closed or non-closed line, which is at least partially angular and/or round and/or elliptical.

5. The degassing channel according to claim 4, wherein the first channel wall has a first releasable wall opening, which is assigned to a first cell-degassing opening of a first battery cell, and has a second releasable wall opening, which is assigned to a second cell-degassing opening of a second battery cell, wherein the material weakening in the region of the first releasable wall opening is designed differently than the material weakening in the region of the second releasable wall opening, so that when the first wall opening is released, an assigned, first gas control property is provided by the released wall opening, which differs from a second gas control property, which is provided by the second, releasable wall opening in the event of release of the second wall opening.

6. A battery assembly with a degassing channel according to claim 1, wherein the battery assembly has a battery with at least one cell pack, which comprises at least one battery cell that has a releasable cell-degassing opening, wherein the degassing channel is arranged on the cell pack in such a way that the releasable wall opening of the first channel wall is arranged opposite the assigned cell-degassing opening.

7. The battery assembly according to claim 6, wherein the battery cell has a first side with two cell pole connections and a second side opposite the first side, on which the cell-degassing opening is arranged.

8. The battery assembly according to claim 6, wherein the degassing channel is arranged on the cell pack in such a way that the releasable wall opening of the first channel wall has a predetermined distance to the assigned, releasable cell-degassing opening to provide a free area between the releasable cell-degassing opening and the releasable wall opening.

9. The battery assembly according to claim 6, wherein a partition surrounding the releasable wall opening and the assigned, releasable cell-degassing opening is arranged between the releasable wall opening and the assigned, releasable cell-degassing opening, which partition separates a free inner region between the releasable cell-degassing opening and the releasable wall opening from an outer region between the cell pack and the degassing channel, which is at least partially filled with a thermally conductive compound.

10. A motor vehicle having a battery assembly according to claim 6.

11. The degassing channel according to claim 2, wherein the degassing channel has a second channel wall opposite the first, which is provided by an underride guard.

12. The degassing channel according to claim 2, wherein the first channel wall has a material weakening in the region of the releasable wall opening to provide a predetermined breaking point for releasing the wall opening, which predetermined breaking point is designed as an engraving on a side of the first channel wall that faces toward or faces away from the second channel wall, and which is provided along a fully closed or non-closed line, which is at least partially angular and/or round and/or elliptical.

13. The degassing channel according to claim 3, wherein the first channel wall has a material weakening in the region of the releasable wall opening to provide a predetermined breaking point for releasing the wall opening, which predetermined breaking point is designed as an engraving on a side of the first channel wall that faces toward or faces away from the second channel wall, and which is provided along a fully closed or non-closed line, which is at least partially angular and/or round and/or elliptical.

14. A battery assembly with a degassing channel according to claim 2, wherein the battery assembly has a battery with at least one cell pack, which comprises at least one battery cell that has a releasable cell-degassing opening, wherein the degassing channel is arranged on the cell pack in such a way that the releasable wall opening of the first channel wall is arranged opposite the assigned cell-degassing opening.

15. A battery assembly with a degassing channel according to claim 3, wherein the battery assembly has a battery with at least one cell pack, which comprises at least one battery cell that has a releasable cell-degassing opening, wherein the degassing channel is arranged on the cell pack in such a way that the releasable wall opening of the first channel wall is arranged opposite the assigned cell-degassing opening.

16. A battery assembly with a degassing channel according to claim 4, wherein the battery assembly has a battery with at least one cell pack, which comprises at least one battery cell that has a releasable cell-degassing opening, wherein the degassing channel is arranged on the cell pack in such a way that the releasable wall opening of the first channel wall is arranged opposite the assigned cell-degassing opening.

17. A battery assembly with a degassing channel according to claim 5, wherein the battery assembly has a battery with at least one cell pack, which comprises at least one battery cell that has a releasable cell-degassing opening, wherein the degassing channel is arranged on the cell pack in such a way that the releasable wall opening of the first channel wall is arranged opposite the assigned cell-degassing opening.

18. The battery assembly according to claim 7, wherein the degassing channel is arranged on the cell pack in such a way that the releasable wall opening of the first channel wall has a predetermined distance to the assigned, releasable cell-degassing opening to provide a free area between the releasable cell-degassing opening and the releasable wall opening.

19. The battery assembly according to claim 7, wherein a partition surrounding the releasable wall opening and the assigned, releasable cell-degassing opening is arranged between the releasable wall opening and the assigned, releasable cell-degassing opening, which partition separates a free inner region between the releasable cell-degassing opening and the releasable wall opening from an outer region between the cell pack and the degassing channel, which is at least partially filled with a thermally conductive compound.

20. The battery assembly according to claim 8, wherein a partition surrounding the releasable wall opening and the assigned, releasable cell-degassing opening is arranged between the releasable wall opening and the assigned, releasable cell-degassing opening, which partition separates a free inner region between the releasable cell-degassing opening and the releasable wall opening from an outer region between the cell pack and the degassing channel, which is at least partially filled with a thermally conductive compound.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0026] Exemplary embodiments of the invention are described hereinafter. The following is shown:

[0027] FIG. 1 a schematic illustration of a battery cell for a battery assembly according to an exemplary embodiment of the invention;

[0028] FIG. 2 a schematic illustration of a battery assembly with several battery cells and a channel wall of a degassing channel according to an exemplary embodiment of the invention;

[0029] FIG. 3 a schematic cross-sectional illustration of a battery assembly with a battery cell arranged on the degassing channel according to an exemplary embodiment of the invention;

[0030] FIG. 4 a schematic cross-sectional illustration of a detailed view of the connection point between the cell-degassing opening and the releasable wall opening according to an exemplary embodiment of the invention; and

[0031] FIG. 5 a schematic illustration of the time sequence during degassing of a battery cell according to an exemplary embodiment of the invention.

DETAILED DESCRIPTION

[0032] 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 features each also refine the invention independently of one another. Therefore, the disclosure is also intended to encompass combinations of the features of the embodiments other than those illustrated. Furthermore, the described embodiments can also be supplemented by further features of the invention previously described.

[0033] In the figures, the same reference numerals designate elements that have the same function.

[0034] FIG. 1 shows a schematic and perspective illustration of a battery cell 10 for a battery assembly 12 according to an exemplary embodiment of the invention. Such an exemplary battery assembly 12 is shown in FIG. 2, for example. The battery cell 10 shown as an example in FIG. 1 is designed as a prismatic battery cell and has a cell housing 14 which provides an upper side 14a and a lower side 14b of the battery cell 10. Two cell pole connections 16, 18 of the battery cell 10 are arranged on the upper side. One of these two cell pole connections 16, 18 is designed as a positive pole and the other as a negative pole. Moreover, additional components can also be arranged on the upper side 14a of the battery cell 10, such as a filling opening 20 for filling the cell housing 14 with an electrolyte during the manufacture of the battery cell 10, a data matrix code 22 which can be provided as a QR code, for example, and a thermochromatic sticker 24.

[0035] Furthermore, such a battery cell 10 has a releasable degassing opening 26. As shown in FIG. 1, this degassing opening can also be arranged on the upper side 14a of the battery cell 10; however, in the exemplary embodiments described below, it is arranged on the lower side 14b of the cell housing 14 instead. Such a degassing opening 26 can be provided, for example, with a bursting membrane that ruptures due to overpressure, which is provided, for example, by a thin metal foil that closes an opening in the cell housing 14.

[0036] In the case of conventional batteries, in particular high-voltage batteries for electric or hybrid vehicles, it is not possible to have direct hot gas control per cell, in particular not downwards. Instead, additional fire protection plates are usually used in the cover of the battery housing; however, they are very expensive and heavy so as to prevent runaway of a cell into the interior of the motor vehicle. However, the invention and the embodiments thereof now make it possible to provide significantly more efficient gas control.

[0037] To this end, FIG. 2 shows a schematic illustration of a battery assembly 12 with several battery cells 10. These battery cells 10 can in particular, as described for FIG. 1, be designed with the difference that now the cell-degassing openings 26 mentioned above are not arranged on the upper side 14a of a relevant cell housing 14, but instead are arranged on the opposite, lower side 14b. Correspondingly, these releasable cell-degassing openings 26 are not visible in the illustration, as in FIG. 2. Furthermore, the battery assembly 12 comprises a degassing channel 28, only part of which is shown in this example, namely a first channel wall 30, which faces the cell pack 32 provided by the several battery cells 10. The degassing channel 28 can be delimited by a second channel wall 34 on a side opposite this first channel wall 30, which in the present case is merely indicated by dashed lines. It is particularly advantageous if the first channel wall 30 is provided, for example, by a cooling base 36 of the battery housing of the battery, which comprises the cell pack 32, and the second channel wall 34 is provided by an underride guard of the motor vehicle. The degassing channel 28 can then advantageously have several releasable wall openings 38 on the first channel wall 30. In this case, each wall opening 38 is assigned to exactly one cell-degassing opening 26. There is also such a releasable wall opening 38 in the first channel wall 30 below each battery cell 10 in FIG. 2. Provision is also made for further battery cells 10 to be arranged above these respective releasable wall openings 38 shown in FIG. 2, which are not shown in FIG. 2 for clearer illustration of the releasable wall openings 38. These releasable wall openings 38 are normally closed and only open when the battery cell in question with the assigned cell-degassing opening 26 outgasses. The gas discharge then takes place through a gradual, controlled opening of these gas control structures provided by the releasable wall openings 38 in the battery housing base 36, which is preferably designed in such a way that there is no blockage with respect to the combination of cell 10 and housing base 36 and the free space located therebetween. The respective releasable wall openings 38 can also be provided as bursting openings, for example as described for the battery cell 10 in relation to the cell-degassing openings 26 thereof, or provided by a differently designed material weakening in the first channel wall 30, for example in the form of an engraving. If an overpressure occurs in a specific cell 10, its underside cell-degassing opening 26 opens first, as a result of which the gas produced in cell 10 can escape therefrom directly onto the assigned, releasable wall opening 38 of the first channel wall 30, which consequently also opens and thereby directs the escaping gas into the interior 40 of the degassing channel 28.

[0038] For better thermal decoupling, it is very advantageous that each cell 10 has its own assigned, releasable wall opening 38. Accordingly, the wall openings 38 preferably have a spacing, in particular in the y-direction, and a width which, in the y-direction, is at most as large as a thickness of the assigned cell 10 in the y-direction, for example 30 mm at most. The thickness of the cells 10 in the y-direction is less than a width of the cells 10 in the y-direction and a height of the cells 10 in the z-direction. Several cells 10 of the cell pack are arranged next to one another in the y-direction.

[0039] FIG. 3 shows a schematic cross-sectional illustration through a battery assembly 12 according to an exemplary embodiment of the invention. This cell assembly 12 in turn comprises a battery cell 10, which can be designed as described above, and a degassing channel 28, which can also be designed as described above. FIG. 4 again shows a detailed illustration of a section from FIG. 3 in the connection region for connecting the releasable cell-degassing opening 26 to the releasable wall opening 38. FIG. 3 also shows the first channel wall 30 preferably designed as a cooling base 36. In other words, the first channel wall 30 preferably provides a base of the battery housing, on which the battery cells 10 are arranged, and which at the same time provides cooling channels 42 through which a cooling medium can flow. Furthermore, in the present case, a respective battery cell 10 is connected to the cooling base 36 via a thermally conductive compound 44, also known as a gap filler. Such a thermally conductive compound 44 can make the heat dissipation from the battery cell 10 to the cooling base 36 more efficient during normal operation. The releasable wall opening 38 is arranged directly opposite the assigned, releasable cell-degassing opening 26 of the battery cell 10, as can be seen clearly in detail, particularly in FIG. 4. It is also advantageous if the releasable wall opening 38 has a definable minimum distance d from the releasable cell-degassing opening 26, which is preferably between 1 and 3 millimeters, for example 2 millimeters. This makes it possible to ensure that a blockage does not occur in the event of successive opening of the cell-degassing opening 26 and subsequently the releasable wall opening 38. Furthermore, in this example, a partition, in this example in the form of an O-ring 46, is arranged in the region between the cell-degassing opening 26 and the releasable wall opening 38. This O-ring 46 is round, corresponding to the releasable wall openings 38 in this example, and around the releasable wall opening 38 and the assigned cell-degassing opening 26, so that a free space 48 is created between the releasable wall opening 38 and the assigned, releasable cell-degassing opening 26. The O-ring 46 keeps this free space 48 free while the gap filler 44 is being filled during the manufacture of the battery. This therefore ensures that no gap filler compound 44 can get into this free space area 48 during production.

[0040] The cooling base 36 can be composed, for example, of a cooling plate 36a and a base plate 36b, between which the cooling channels 42 are formed and which can each be in the form of metal sheets, for example. The releasable wall opening 38 can then be formed accordingly in one of these metal sheets 36a, 36b, for example in the base plate 36b in this case.

[0041] It is particularly advantageous here, for example, if this releasable wall opening 38 is provided, for example, by an engraving in the base 36 for a respective, assigned cell-degassing opening 26. This engraving opens up when the degassing pressure of the cells 10 increases and directs the gas flow between the base sheet 36 and the underride guard 34 to the outside in a targeted manner. As a result, the spreading to further cells 10 can be prevented or at least delayed by the improved thermal decoupling. This gradual, controlled opening will now be described in more detail with reference to FIG. 5.

[0042] To this end, FIG. 5 shows a time sequence of such an opening process in the event of outgassing of a battery cell 10. In this case, FIG. 5 shows the battery assembly 12 or the part thereof for four different points in time t1, t2, t3, t4, which is also illustrated as relates to FIG. 4. The battery assembly 12 can thus in turn be designed as previously described.

[0043] At the first point in time t1, both the cell-degassing opening 26 and the releasable wall opening 38 are still in an intact state. This means that both the cell-degassing opening 26 and the assigned, releasable wall opening 38 are still closed in this situation. Due to a thermal event in the cell 10, a gas 52 develops in the interior 50 of the battery cell 10, which leads to an increased gas pressure inside this battery cell 10. As shown at point in time t1, this increased gas pressure acts on the releasable cell-degassing opening 26 and, when a specific threshold value is exceeded, causes this cell-degassing opening 26 to open, as is the case at point in time t2. The gas stream 52 consequently flowing out of the cell 10 is then correspondingly directed directly onto the assigned, releasable wall opening 38, which consequently also opens, as is illustrated in FIG. 5 at point in time t3. Due to the ongoing gas flow 52, parts of the cell housing 14 as well as the channel wall 30 form outwards in the region of the respective cell-degassing opening 26 and wall opening 38, i.e. in the direction of the interior 40 of the degassing channel 28. This end state is shown in FIG. 5 at point in time t4. The gas flow 52 thus reaches the interior 40 of the degassing channel, which is provided by the intermediate space between the underride guard 34 and the cooling base 36 of the battery or the vehicle. In this intermediate space, the outflowing gas 52 can also be routed to an exhaust pipe or directly out of the vehicle in a targeted manner.

[0044] Overall, the examples show how an actively controllable degassing system can be provided by the invention, according to which a gas opening system is preferably integrated directly into the base. The base can be partially engraved under the cells. This engraving opens up when the degassing pressure of the cells increases and directs the gas flow between the base sheet and underride guard outwards in a targeted manner to prevent the spreading to other cells. This enables the hot gas to be discharged quickly and protects the occupants of the motor vehicle for a longer period of time. In addition, cost and weight savings can be achieved by dispensing with additional measures.