Storage battery pack

Abstract

The present invention addresses the problem of suppressing a cover body from floating or falling off due to gas discharged from a relief valve. In order to solve the problem, the present invention provides a battery pack provided with a plurality of battery cells, a case, a cover body, a discharge part, and a duct member. The case accommodates a battery stack in which battery cells are stacked in a predetermined stacking direction. The cover body covers the opening of the shell. Each battery cell is provided with a safety valve capable of discharging gas in the battery cell. The discharge portion discharges the gas discharged from the relief valve to the inside of the housing to the outside of the housing. The duct member extends in the stacking direction between the relief valve and the cover, and guides the gas to the discharge portion by guiding the gas in the stacking direction.

Description

Technical Field

[0001] The present invention relates to a battery pack. Background Art

[0002] In recent years, from the viewpoints of reducing carbon dioxide emissions and minimizing adverse impacts on the global environment, electric vehicles such as pure electric vehicles (EV) and hybrid electric vehicles (HEV) have been increasingly popularized. Among the battery packs installed in electric vehicles and the like, there are battery packs including a battery laminate, a case, and a lid. The battery laminate is formed by laminating a plurality of battery cells in a specified lamination direction. The case houses the battery laminate. The lid covers the opening of the case. Each battery cell has a safety valve at the end on the lid side capable of discharging the internal gas. Therefore, when a battery cell undergoes thermal runaway, the gas inside the battery cell is discharged from the safety valve to the inside of the case.

[0003] [Prior Art Documents]

[0004] (Patent Documents)

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2022 - 86449 Summary of the Invention

[0006] [Problems to be Solved by the Invention]

[0007] The inventors of the present invention have noted that the following problems may occur in such a battery pack. When a battery cell undergoes thermal runaway, the gas discharged from the safety valve to the inside of the case directly hits the lid. As a result, the lid may float or come off.

[0008] In view of the above circumstances, the present invention aims to suppress the lid from floating or coming off due to the gas discharged from the safety valve.

[0009] [Technical Means for Solving the Problems]

[0010] The inventors of the present invention have found that by providing a pipe member between the battery laminate and the lid, the above object can be achieved, and thus the present invention has been completed. The present invention is a battery pack as described in the following (1) to (8).

[0011] (1) A battery pack, comprising:

[0012] a plurality of battery cells;

[0013] a case that houses the battery laminate formed by laminating the battery cells in a specified lamination direction; and

[0014] a lid that covers the opening of the case;

[0015] Each of the above-described battery cells is provided with a safety valve capable of discharging the gas inside the battery cell, and the battery pack includes:

[0016] A discharge portion for discharging the gas discharged from the safety valve to the inside of the housing to the outside of the housing; and,

[0017] A pipe member extending in the stacking direction between the safety valve and the lid body, and guiding the gas to the discharge portion by guiding the gas in the stacking direction.

[0018] According to this structure, the gas discharged from the safety valve collides with the pipe member. Therefore, compared with the case where the gas directly hits the lid body, it is possible to suppress the lid body from floating or falling off.

[0019] (2) The battery pack according to the above (1), which includes: a plurality of bus bars that electrically connect the electrodes of the battery cells to each other; and a bus bar holder that serves as a member for separating the bus bars from each other;

[0020] An exhaust flow path is formed by the lid body and the bus bar holder,

[0021] The pipe member is provided in the exhaust flow path.

[0022] According to this structure, the bus bar holder can be effectively utilized to form an exhaust flow path.

[0023] (3) The battery pack according to the above (2), wherein the bus bar holder includes: a bus bar holder base portion extending in the stacking direction; a plurality of cross member portions respectively extending outward in the orthogonal direction from both ends of the bus bar holder base portion in the orthogonal direction orthogonal to the stacking direction; and a longitudinal member portion connecting the outer ends of the cross member portions in the orthogonal direction;

[0024] The exhaust flow path is formed by the lid body and the bus bar holder base portion.

[0025] According to this structure, the bus bar holder base portion can be effectively utilized to form an exhaust flow path.

[0026] (4) The battery pack according to the above (2) or (3), wherein the pipe member is shaped to be deformed by the pressure of the gas and pressed against the bus bar holder,

[0027] By pressing the pipe member against the bus bar holder, the movement of the pipe member toward the lid body side caused by the gas is suppressed.

[0028] According to this configuration, since the movement of the pipe component toward the lid body side is suppressed, it is possible to more firmly suppress the pipe component from pushing the lid body and causing the lid body to float or fall off. Further, since the pipe component is pressed against the bus bar holder rather than the bus bar, it is possible to suppress the thermal influence on the bus bar.

[0029] (5) The battery pack according to (4) above, wherein the pipe component has: a plate-shaped pipe base portion that extends in the stacking direction between the safety valve and the lid body; and pipe side wall portions that project toward the battery stack body side from both ends in the orthogonal direction orthogonal to the stacking direction in the pipe base portion.

[0030] Each of the pipe side wall portions is opened outward in the orthogonal direction by the pressure of the gas, thereby pressing each of the pipe side wall portions against the bus bar holder, thereby suppressing the movement.

[0031] According to this configuration, by pressing each pipe side wall portion against the bus bar holder, the movement of the pipe component toward the lid body side caused by the gas is suppressed. Moreover, even if the pipe component pushes the lid body and causes the lid body to slightly float, it is still possible to suppress the outflow of the gas to the outside in the orthogonal direction by each pipe side wall portion. Therefore, it is possible to suppress the outflow of the gas to the bus bar side or the like.

[0032] (6) The battery pack according to (5) above, wherein each of the pipe side wall portions has an inclined portion that goes more inward in the orthogonal direction the closer it is to the battery stack body side.

[0033] According to this configuration, each pipe side wall portion has an inclined portion, whereby each pipe side wall portion is easily subjected to the pressure of the gas and is easily pressed against the bus bar holder. Moreover, even if the pipe component pushes the lid body and causes the lid body to slightly float, the length of the pipe side wall portion in the floating direction of the lid body is extended due to the shallow inclination angle of the inclined portion. Therefore, it is possible to stably suppress the outflow of the gas to the outside in the orthogonal direction by each pipe side wall portion.

[0034] (7) The battery pack according to (2) or (3) above, wherein an elastic member is provided between the pipe component and the bus bar holder.

[0035] When the pipe component is deformed by the pressure of the gas, the elastic member suppresses the abnormal noise caused by the contact between the pipe component and the bus bar holder.

[0036] According to this configuration, abnormal noise can be suppressed.

[0037] (8) The battery pack according to any one of (1) to (3) above, wherein a drooping plate for guiding the gas to the discharge portion is provided at an end portion in the stacking direction of the pipe component.

[0038] According to this configuration, the gas guided to the end of the pipe component can be guided to the discharge part by the drooping plate.

[0039] (Effect of the Invention)

[0040] As described above, according to the configuration of the foregoing (1), it is possible to suppress the lid from floating or falling off due to the gas discharged from the safety valve. Furthermore, according to the configurations of the foregoing (2) to (8) citing the foregoing (1), respective additional effects can be obtained. Description of the Drawings

[0041] Figure 1 is a front sectional view of the battery pack of the first embodiment, specifically, it is a view showing the Figure 2 section along line II-II.

[0042] Figure 2 is a view showing the Figure 1 section along line II-II.

[0043] Figure 3 is a view showing the Figure 1 section along line III-III.

[0044] Figure 4 is a view showing the Figure 1 section along line IV-IV.

[0045] Figure 5 is a view showing the Figure 2 section along line V-V.

[0046] Figure 6 is a perspective view of the bus bar holder.

[0047] Figure 7 is a perspective view of the bus bar holder and the pipe component.

[0048] Figure 8 is Figure 7 a sectional view of a part of

[0049] Figure 9 is a front sectional view of the pipe component and its surroundings when gas is discharged. Detailed Embodiments

[0050] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Among them, the present invention is not limited to the following embodiments, and can be appropriately modified and implemented without departing from the gist of the present invention.

[0051] [First Embodiment]

[0052] As Figure 1As shown, the battery pack 100 includes a housing 80, two battery laminates Bs, two bus bar holders 60, two pipe components 20, a plurality of bus bars 50, a plurality of heat transfer components 40, and a cover 30.

[0053] Hereinafter, as Figure 2 shown, two specified directions orthogonal to each other in the horizontal plane are referred to as the "X direction" and the "Y direction". In addition, one of the X directions is referred to as the "X− direction", and the opposite direction thereof is referred to as the "X+ direction". In addition, one of the Y directions is referred to as the "Y− direction", and the opposite direction thereof is referred to as the "Y+ direction".

[0054] As Figure 1 shown, the housing 80 has a box shape that is open upward, and houses the two battery laminates Bs side by side in the X direction. The material of the housing 80 is metal or the like.

[0055] As Figure 5 shown, each battery laminate Bs includes a plurality of battery cells 70 and a plurality of separators 79. As Figure 4 shown, each battery cell 70 has a rectangular outer package that is elongated in the X direction. In each battery laminate Bs, the battery cells 70 are stacked in the Y direction. Therefore, the "Y direction" can also be alternatively referred to as the "stacking direction". In addition, the "X direction" can also be alternatively referred to as the "orthogonal direction orthogonal to the stacking direction" or the "orthogonal direction". Figure 5 The separator 79 shown is a plate-like member that extends in the X direction and the up and down directions, and is disposed between two battery cells 70 juxtaposed in the Y direction. The material of the separator 79 is resin or the like.

[0056] As Figure 1 shown, plate-like spacers 89 that extend in the Y direction and the up and down directions are provided between the battery laminate Bs on the X− direction side and the housing 80, between the two battery laminates Bs, and between the battery laminate Bs on the X+ direction side and the housing 80. The material of the spacers 89 is resin or the like.

[0057] As Figure 4 shown, spacers 85 are respectively inserted between the two ends in the X direction of the end face on the Y− direction side in each battery laminate Bs and the housing 80. By these spacers 85, a space S is formed between the end face on the Y− direction side in each battery laminate Bs and the housing 80.

[0058] As Figure 4As shown, each battery cell 70 has a positive electrode p at one end in the X direction on the upper surface of the outer package, and a negative electrode n at the other end in the X direction on the upper surface of the outer package. Specifically, for a specified plurality of battery cells 70, the positive electrode p is disposed on the X− direction side, and the negative electrode n is disposed on the X+ direction side. On the other hand, for the other battery cells 70, the negative electrode n is disposed on the X− direction side, and the positive electrode p is disposed on the X+ direction side.

[0059] As Figure 3 shown, most of the busbars 50 electrically connect the electrodes p and n of the battery cells 70 adjacent in the X direction or the Y direction to each other. On the other hand, one specified busbar 50 electrically connects the positive electrode p of the battery cell 70 on the most positive side electrically to the positive electrode P of the entire battery pack 100. In addition, another busbar 50 electrically connects the negative electrode n of the battery cell 70 on the most negative side electrically to the negative electrode N of the entire battery pack 100.

[0060] Based on the above, in the present embodiment, all the battery cells 70 in the battery pack 100 are connected in series. Each busbar 50 is formed, for example, by bending a single metal plate. A fitting recess 54 is formed on the upper surface of each busbar 50. A fitting convex portion 45 described later in the heat transfer member 40 fits into the fitting recess 54.

[0061] As Figure 4 shown, each battery cell 70 has a safety valve 76 capable of discharging the gas inside the battery cell 70 at the central portion on the upper surface of the outer package. Specifically, the portion of the upper surface of the outer package of each battery cell 70 that constitutes the safety valve 76 is configured to be weaker than other portions. Thus, when the pressure inside the battery cell 70 rises, that is, when the pressure inside the outer package rises, the portion of the outer package that constitutes the safety valve 76 is damaged first, and the pressure is released here.

[0062] Figure 4 The busbar holder 60 shown is an insulating member such as resin, and is provided for each battery laminate Bs. Each busbar holder 60 is a member for separating the busbars 50 from each other. Specifically, each busbar holder 60 has one busbar holder base 62, a plurality of cross members 67, and two longitudinal members 68.

[0063] The busbar holder base 62 extends in the Y direction at the central portion in the X direction on the upper surface of the battery laminate Bs corresponding to itself. Specifically, as Figure 6As shown, the bus bar holder base 62 has a plate-shaped bottom 62a with the Y direction as the length direction and the X direction as the width direction, and side portions 62c protruding upward from both ends in the X direction of the bottom 62a. In the bottom 62a, for each safety valve 76, a communication hole 62b communicating with the safety valve 76 is provided.

[0064] Each cross member portion 67 extends outward in the X direction from both end portions in the X direction of the bus bar holder base 62. As Figure 3 shown, each cross member portion 67 is disposed between bus bars 50 arranged in parallel in the Y direction, or between the bus bar 50 at the end in the Y direction and the housing 80. As Figure 6 shown, each longitudinal member portion 68 extends in the Y direction and connects the end portions outside the X direction of the cross member portions 67 to each other.

[0065] Figure 1 The cover body 30 shown is a plate-shaped member extending in the X direction and the Y direction, and covers the opening of the housing 80. The material of the cover body 30 is metal or the like. The space surrounded by the cover body 30 and the bus bar holder base 62 constitutes the exhaust flow path Eg. That is, the exhaust flow path Eg is formed by the cover body 30 and the bus bar holder base 62.

[0066] Figure 2 The heat transfer member 40 shown is provided for Figure 3 each bus bar 50 shown. Figure 2 Each heat transfer member 40 shown is an insulator such as rubber or resin. As Figure 3 shown, the above-mentioned engaging convex portion 45 is provided on the lower surface of the heat transfer member 40. By engaging the engaging convex portion 45 with the engaging concave portion 54 of the bus bar 50, each heat transfer member 40 is positioned relative to the corresponding bus bar 50. Due to the above, as Figure 1 shown, each heat transfer member 40 is disposed between the corresponding bus bar 50 and the cover body 30. The lower surface of each heat transfer member 40 abuts against the bus bar 50, and the upper surface of each heat transfer member 40 abuts against the cover body 30.

[0067] As Figure 4 shown, in a portion of the housing 80 that is more on the -Y direction side than the battery stack Bs, a discharge portion 82 is provided for discharging the gas discharged from the safety valve 76 to the inside of the housing 80 to the outside of the housing 80. The discharge portion 82 is a pressure relief valve or the like. Specifically, in the present embodiment, a discharge portion 82 is provided for each battery stack Bs.

[0068] Figure 2 The pipe member 20 shown is provided for each bus bar holder base 62. The pipe member 20 is a member for guiding the gas discharged from the safety valve 76 to the discharge portion 82 and extends in the Y direction. As Figure 1As shown, each pipe component 20 is disposed within the exhaust passage Eg between the safety valve 76 and the cover body 30.

[0069] As Figure 8 shown, the pipe component 20 includes a pipe base portion 22 and pipe side wall portions 25. The pipe base portion 22 is a plate-like component with the Y direction as the length direction and the X direction as the width direction, and is disposed between the safety valve 76 and the cover body 30 as Figure 1 shown.

[0070] As Figure 1 shown, the pipe side wall portions 25 protrude downward, i.e., toward the battery stack Bs side, from both ends in the X direction of the pipe base portion 22. More specifically, each pipe side wall portion 25 has a root portion 25a, an inclined portion 25b, and a front end portion 25c. The root portion 25a extends downward from both ends in the X direction of the pipe base portion 22. The inclined portion 25b extends toward the lower side inside the X direction from the lower end of the root portion 25a. Thus, the inclined portion 25b moves more toward the inside in the X direction as it gets closer to the lower side, i.e., the battery stack Bs side. The front end portion 25c extends toward the upper side inside the X direction from the front end of the inclined portion 25b. The straight-line length of each pipe side wall portion 25 is longer than the length in the up-down direction of the pipe side wall portion 25. That is, the straight-line length from the base end of the root portion 25a to the front end of the front end portion 25c is longer than the length in the up-down direction from the base end of the root portion 25a to the front end of the inclined portion 25b.

[0071] An elastic member 29 is provided between the pipe side wall portion 25 and the bottom portion 62a of the bus bar holder base 62. The material of the elastic member 29 is rubber or resin, etc.

[0072] As Figure 9 shown, when gas is discharged from the safety valve 76, the inclined portion 25b is subjected to the pressure of the gas, causing each pipe side wall portion 25 to open outward in the X direction. Thus, each pipe side wall portion 25 is pressed against the side portion 62c of the bus bar holder base 62. Thereby, the upward movement of the pipe component 20 caused by the gas, i.e., the movement toward the cover body 30 side, is suppressed.

[0073] As Figure 7 shown, the pipe component 20 further has a drooping plate 21. The drooping plate 21 extends downward toward the Y- direction side from the end portion in the Y- direction of the pipe base portion 22. The gas reaching the drooping plate 21 as Figure 5 shown is guided by the drooping plate 21 to the discharge portion 82.

[0074] Hereinafter, the structure and effects of this embodiment will be summarized.

[0075] As Figure 9As shown, the gas discharged from the safety valve 76 collides with the pipe member 20. Therefore, compared with the case where the gas directly hits the cover body 30, the floating or detachment of the cover body 30 can be suppressed.

[0076] The cover body 30 and the bus bar holder base 62 form an exhaust passage Eg. The pipe member 20 is provided in the exhaust passage Eg. Therefore, the bus bar holder base 62 can be effectively utilized to form the exhaust passage Eg.

[0077] The pipe member 20 is shaped such that it deforms due to the pressure of the gas and is pressed against the bus bar holder 60. By this pressing, the upward movement of the pipe member 20 caused by the gas, that is, the movement toward the cover body 30 side, is suppressed. Therefore, the pipe member 20 pressing against the cover body 30 to cause the cover body 30 to float or detach is more firmly suppressed. Furthermore, since the pipe member 20 is pressed against the bus bar holder 60 instead of the bus bar 50, the thermal influence on the bus bar 50 can be suppressed.

[0078] The pipe member 20 has a pipe base 22 and pipe side wall portions 25. The pipe side wall portions 25 protrude downward, that is, toward the battery laminate side, from both ends in the X direction of the pipe base 22. When gas is discharged from the safety valve 76, each pipe side wall portion 25 is opened outward in the X direction by the pressure of the gas, and thereby, each pipe side wall portion 25 is pressed against the bus bar holder 60. By this pressing, the upward movement of the pipe member 20 caused by the gas can be suppressed. Moreover, even if the pipe member 20 pushes up the cover body 30 to cause the cover body 30 to slightly float, the outflow of the gas to the outside in the X direction, that is, Figure 1 the bus bar 50 side shown, can still be suppressed by each pipe side wall portion 25.

[0079] As Figure 9 shown, each pipe side wall portion 25 has an inclined portion 25b that goes more inward in the X direction the closer it is to the battery laminate Bs side. By this inclined portion 25b, each pipe side wall portion 25 is easily subjected to the pressure of the gas and is easily pressed against the bus bar holder 60. Moreover, even if the pipe member 20 pushes up the cover body 30 to cause the cover body 30 to slightly float, the vertical length of the pipe side wall portion 25 is extended due to the shallower inclination angle below with respect to the inclined portion 25b. That is, the length of the pipe side wall portion 25 in the floating direction of the cover body 30 is extended. Therefore, the outflow of the gas to the outside in the X direction can be stably suppressed by each pipe side wall portion 25.

[0080] An elastic member 29 is provided between each pipe side wall portion 25 and the bus bar holder 60. Therefore, when the pipe member 20 deforms due to the pressure of the gas, the abnormal noise caused by the contact between the pipe side wall portion 25 and the bus bar holder 60 is suppressed by the elastic member 29. Therefore, the abnormal noise can be suppressed.

[0081] As Figure 5As shown, at the Y-direction end of the pipe component 20, there is a drooping plate 21 that guides the gas to the discharge part 82. Therefore, the gas guided to the Y-direction end of the pipe component 20 can be guided to the discharge part 82 by the drooping plate 21.

[0082] [Other Embodiments]

[0083] The embodiments shown above can be modified as follows, for example. Figure 1 The shown housing 80 can house either only one battery laminate Bs or three or more. In Figure 4 Inside the shown housing 80, multiple parallel-connected bodies of a specified number, such as two or three, of battery cells 70 can also be connected in series.

[0084] In Figure 3 , the engaging recesses 54 of each bus bar 50 and the engaging protrusions 45 of each heat transfer component 40 extend in the X direction, but they can also extend in the Y direction. Additionally, conversely, Figure 3 a protrusion for engagement can be provided on the bus bar 50, and an engaging recess for engaging with this protrusion can be provided on the heat transfer component 40.

[0085] In cases where, even without Figure 3 the shown bus bar holder 60, sufficient insulation between the bus bars 50 can still be ensured, etc., the bus bar holder 60 can also be absent. In this case, Figure 1 the shown exhaust flow path Eg can also be formed between a dedicated component for forming this exhaust flow path Eg and the cover body 30.

[0086] In Figure 9 even if each shown pipe side wall part 25 has a shape that simply extends straight downward from the X-direction end of the pipe base 22, and yet it will fully open outward in the X direction due to the gas pressure, etc., the pipe side wall part 25 can also have this shape.

[0087] In cases where, even without Figure 9 the shown elastic component 29, the abnormal noise caused by the pipe side wall part 25 contacting the bottom 62a of the bus bar holder base 62 hardly becomes a problem, etc., the elastic component 29 can also be absent. In cases where, even without Figure 5 the shown drooping plate 21, the gas guided to the Y-direction end of the pipe component 20 can still be fully guided to the discharge part 82, etc., the drooping plate 21 can also be absent.

[0088] Reference Numerals

[0089] 20 Pipe Component

[0090] 21 Drooping Plate

[0091] 22 Pipe base

[0092] 25 Pipe side wall part

[0093] 25b Inclined part

[0094] 30 Cover body

[0095] 50 Bus bar

[0096] 60 Bus bar holder

[0097] 62 Bus bar holder base

[0098] 67 Cross member part

[0099] 68 Longitudinal member part

[0100] 70 Battery cell

[0101] 76 Safety valve

[0102] 80 Housing

[0103] 82 Discharge part

[0104] Bs Battery laminate

Claims

1. A battery pack comprising: Multiple battery cells; a housing for accommodating a battery stack formed by stacking the battery cells in a predetermined stacking direction; and A cover body, covering the opening of the shell; Each of the battery cells is provided with a safety valve capable of discharging gas in the battery cell, and the battery pack comprises: a discharge portion for discharging the gas discharged from the safety valve to the inside of the housing to the outside of the housing; and The duct member extends in the stacking direction between the safety valve and the cover body, and guides the gas to the discharge portion by guiding the gas in the stacking direction.

2. The battery pack according to claim 1, wherein: The battery cell is provided with: a plurality of bus bars for electrically connecting the electrodes of the battery cells to each other; and a bus bar holder for separating the bus bars from each other; The exhaust channel is formed by the cover and the busbar holder. The exhaust flow passage is provided with the duct member.

3. The battery pack according to claim 2, wherein: The busbar holder comprises: a busbar holder base extending in the stacking direction; a plurality of horizontal members extending from both ends of the busbar holder base in a direction orthogonal to the stacking direction to the outside of the orthogonal direction; and a vertical member connecting the ends of the horizontal members in the orthogonal direction to each other. The exhaust flow channel is formed by the cover and the busbar holder base.

4. The battery pack according to claim 2 or 3, wherein: The pipe member is shaped so as to be pressed against the busbar holder by the pressure of the gas. By pressing the duct component tightly against the busbar holder, movement of the duct component toward the cover body caused by the gas is suppressed.

5. The battery pack according to claim 4, wherein: The duct member comprises: a plate-shaped duct base extending in the stacking direction between the safety valve and the cover; and a duct side wall protruding from both ends of the duct base in a direction orthogonal to the stacking direction toward the battery stack side; Each of the duct side walls is opened outward in the orthogonal direction by the pressure of the gas, thereby pressing each of the duct side walls against the busbar holder, thereby suppressing the movement.

6. The battery pack according to claim 5, wherein: Each of the duct side wall portions has an inclined portion that is inclined toward the inner side in the orthogonal direction as it approaches the battery stack side.

7. The battery pack according to claim 2 or 3, wherein: An elastic member is provided between the aforementioned pipe member and the aforementioned busbar holder, When the duct member is deformed by the pressure of the gas, the elastic member suppresses abnormal noise caused by the duct member contacting the busbar holder.

8. The battery pack according to any one of claims 1 to 3, wherein: A hanging plate for guiding the gas to the discharge portion is provided at an end portion of the duct member in the stacking direction.

Images