Battery pack

Abstract

The present invention addresses the problem of ensuring the rigidity of a jacket while accommodating a plurality of battery stacks in a case so as to be aligned in the width direction. In order to solve the problem, a battery pack is provided with battery cells, a case, a cover, and a jacket. The case accommodates a plurality of battery stacked bodies in which battery cells are stacked in a predetermined stacking direction, the plurality of battery stacked bodies being arranged in a width direction orthogonal to the stacking direction. The cover body covers the housing from the upper side. Each battery cell has a safety valve on the upper surface. The cover body is provided with a flow path forming portion protruding upward for each of the battery stacked bodies. A smoke discharge flow path communicating with the safety valve is formed between each flow path forming part and the battery stack. The jacket covers the cover body from the upper side. A cooling flow path is formed between the cover body and the jacket. The jacket is joined to each of the flow path forming portions.

Description

Technical Field

[0001] The present invention relates to a battery pack containing a plurality of battery cells. Background Art

[0002] In recent years, electric vehicles such as electric vehicles (EV) and hybrid electric vehicles (HEV) have become popular from the perspective of reducing carbon dioxide emissions and reducing adverse effects on the earth's environment. Among the battery packs mounted on electric vehicles, there are battery packs having a battery stack and a shell. The battery stack is formed by stacking a plurality of battery cells in a predetermined stacking direction. The shell accommodates the battery stack. The cover covers the battery stack from the upper side.

[0003] [Prior Technical Literature]

[0004] (Patent Document)

[0005] Patent Document 1: Japanese Patent No. 6658387 Summary of the invention

[0006] [Problems to be solved by the invention]

[0007] The inventors of the present invention consider that in such a battery pack, the cover body is further covered with a jacket from the upper side, and at the same time, a refrigerant is allowed to flow between the cover body and the jacket. According to this structure, the battery pack can be cooled effectively. However, the inventors of the present invention focus on the following problems that may arise.

[0008] If a plurality of battery stacks are housed side by side in a case in a width direction perpendicular to the stacking direction, the case will be enlarged in the width direction, thereby reducing the rigidity of the jacket mounted on the case.

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to house a plurality of battery stacks in a case so as to be aligned in the width direction while ensuring the rigidity of the jacket.

[0010] [Technical means to solve the problem]

[0011] The inventors have found that the above object can be achieved by providing a flow path forming portion on the cover for each battery stack and bonding a jacket to each flow path forming portion, thereby achieving the present invention. The present invention is a battery pack according to the following (1) to (4).

[0012] (1) A battery pack comprising: a plurality of battery cells; a housing for accommodating a plurality of battery stacks in which the battery cells are stacked in a predetermined stacking direction and arranged in a width direction orthogonal to the stacking direction; and a cover for covering the housing from above;

[0013] Each of the battery cells has a safety valve on the upper surface that can discharge the internal gas; wherein,

[0014] The cover body is provided with a flow path forming portion protruding upward and extending in the stacking direction for each of the battery stacks.

[0015] A smoke exhaust flow path communicating with the safety valve is formed between each of the flow path forming portions and the battery stack.

[0016] The battery pack further comprises a jacket covering the cover from above.

[0017] A cooling flow path for circulating a refrigerant is formed between the cover and the jacket, and the jacket is joined to each of the flow path forming portions.

[0018] According to this configuration, since a plurality of battery stacks are accommodated in the housing in an array along the width direction, the housing is enlarged in the width direction. However, the jacket is engaged with the flow path forming portion located in each battery stack, thereby ensuring rigidity. Therefore, according to this configuration, while arranging a plurality of battery stacks in the housing in the width direction, the rigidity of the jacket can also be ensured.

[0019] (2) The battery pack according to (1), wherein:

[0020] A flow path component is mounted on the upper surface of the battery stack.

[0021] Conductive members for electrically connecting the electrodes of the battery cells to each other are provided on both sides of the upper surface of each of the battery stacks in the width direction sandwiching the flow path member.

[0022] The flow path member includes a bottom portion extending in the stacking direction and side portions protruding upward from both ends of the bottom portion in the width direction.

[0023] A connecting hole communicating with the safety valve is provided at the bottom of the flow path component.

[0024] The portion of the cover body where the flow path forming portion is provided is supported by the side portion of the flow path member.

[0025] The portion surrounded by the flow path component and the flow path forming portion is the smoke exhaust flow path.

[0026] The smoke exhaust flow path and the conductive member are separated by a side portion of the flow path member and the flow path forming portion.

[0027] According to this configuration, the portion of the cover body where the flow path forming portion is provided is supported by the side portion of the flow path component. Therefore, the rigidity of the cover body can be ensured. The jacket is joined to the cover body. Therefore, the rigidity of the jacket can also be ensured in this respect. In addition, according to this configuration, the smoke exhaust flow path and the conductive component are separated by the side portion of the flow path component and the flow path forming portion. Therefore, when the contents of the battery cell flow out of the safety valve, the side portion of the flow path component and the flow path forming portion prevent the contents from contacting the conductive component and causing a short circuit.

[0028] (3) The battery pack according to (1) or (2), wherein:

[0029] Conductive members for electrically connecting the electrodes of the battery cells to each other are provided on both sides of the upper surface of each of the battery stacks in the width direction sandwiching the safety valve.

[0030] A heat conducting component is arranged between the conductive component and the cover.

[0031] The lower surface of the thermally conductive component abuts against the conductive component, and the upper surface of the thermally conductive component abuts against the cover.

[0032] According to this configuration, the heat of the battery cell is dissipated from the electrode to the coolant in the cooling flow path via the conductive member, the heat conductive member, and the cover body. Therefore, the battery cell can be cooled efficiently.

[0033] (4) The battery pack according to (1) or (2), wherein:

[0034] The jacket is joined to each of the flow path forming portions by friction stir welding.

[0035] According to this configuration, the jacket and the flow path forming portion can be easily joined together. By this joining, the rigidity of the jacket can be effectively ensured.

[0036] [Effects of the invention]

[0037] As described above, according to the configuration of (1), the rigidity of the jacket can be ensured while arranging a plurality of battery stacks in the width direction in the case. Furthermore, according to the configurations of (2) to (4) citing (1), additional effects can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 FIG. 1 is a front cross-sectional view showing a battery pack according to the first embodiment.

[0039] Figure 2 is a plan view showing a battery pack.

[0040] Figure 3 Is the drawing along Figure 1A cross-section diagram along line III-III is shown.

[0041] Figure 4 Is the drawing along Figure 1 A cross-sectional view along line IV-IV is shown.

[0042] Figure 5 Is the drawing along Figure 1 A cross-sectional view along line VV is shown.

[0043] Figure 6 Is the drawing along Figure 1 A cross-sectional view along line VI-VI is shown. DETAILED DESCRIPTION

[0044] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments in any way, and can be implemented with appropriate changes within the scope of the present invention.

[0045] [First embodiment]

[0046] like Figure 1 As shown, the battery pack 100 includes a case 80 , two battery stacks Bs, two flow path members 60 , a plurality of conductive members 50 , a plurality of thermal conductive members 40 , a cover 30 , and a jacket 20 .

[0047] The following, such as Figure 2 As shown in FIG. 1 , two predetermined directions orthogonal to each other in a horizontal plane are referred to as “X direction” and “Y direction”. In addition, one of the X directions is referred to as “X-direction”, and the opposite direction thereof is referred to as “X+ direction”. In addition, one of the Y directions is referred to as “Y-direction”, and the opposite direction thereof is referred to as “Y+ direction”.

[0048] like Figure 1 As shown, the case 80 is in the shape of a box opened upward, and accommodates two battery stacks Bs arranged in the X direction. The material of the case 80 is metal or the like. The case 80 does not have a partition plate for separating the battery stacks Bs from each other.

[0049] like Figure 6As shown, each battery stack Bs includes a plurality of battery cells 70 and a plurality of spacers 79. Each battery cell 70 has a square exterior. Specifically, for each battery cell 70, the X direction is set as the width direction, the Y direction is set as the depth direction, and the up-down direction is set as the height direction. Therefore, the "X direction" can also be renamed as the "width direction". In each battery stack Bs, the battery cells 70 are stacked in the Y direction. Therefore, the "Y direction" can also be renamed as the "stacking direction". The spacer 79 is a plate-shaped component extending in the X direction and the up-down direction, and is arranged between each two battery cells 70 arranged in the Y direction. The material of the spacer 79 is resin or the like.

[0050] Plate-shaped separators 89 extending in the Y direction and in the vertical direction are provided between the battery stack Bs on the X-direction side and the case 80, between the two battery stacks Bs, and between the battery stack Bs on the X+direction side and the case 80. The separators 89 are made of resin or the like.

[0051] Each battery cell 70 has a positive electrode p at one end in the X direction of the upper surface of the exterior, and a negative electrode n at the other end in the X direction of the upper surface of the exterior. Specifically, for a predetermined plurality of battery cells 70, a positive electrode p is arranged on the X- direction side, and a negative electrode n is arranged on the X+ direction side. On the other hand, for the other battery cells 70, a negative electrode n is arranged on the X- direction side, and a positive electrode p is arranged on the X+ direction side.

[0052] like Figure 5 As shown, most of the conductive members 50 electrically connect the electrodes p and n of the battery cells 70 adjacent to each other in the X direction or the Y direction. On the other hand, a predetermined conductive member 50 electrically connects the positive electrode p of the battery cell 70 on the most electrically positive side to the positive electrode P of the entire battery pack 100. In addition, another conductive member 50 electrically connects the negative electrode n of the battery cell 70 on the most electrically negative side to the negative electrode N of the entire battery pack 100.

[0053] As described above, in this embodiment, all battery cells 70 in the battery pack 100 are connected in series. The conductive member 50 is formed by, for example, bending a metal plate. An engaging recess 54 is formed on the upper surface of the conductive member 50. The engaging recess 54 engages with the engaging protrusion 45 of the heat conductive member 40 described later.

[0054] like Figure 6As shown, each battery cell 70 has a safety valve 76 in the center of the upper surface of the outer casing that can discharge the gas inside the battery cell 70. Specifically, the portion of the upper surface of the outer casing of each battery cell 70 that constitutes the safety valve 76 is configured to be more fragile than other portions. Therefore, when the pressure inside the battery cell 70 increases, that is, when the pressure inside the outer casing increases, the portion of the outer casing that constitutes the safety valve 76 is destroyed first, and the pressure is reduced from this point.

[0055] Each flow path component 60 is a component of an insulator such as resin, and is provided on each battery stack Bs. Specifically, for example, each flow path component 60 may also be a part of a busbar holder that separates the conductive components 50 from each other. Each flow path component 60 is installed in the central part of the upper surface of the battery stack Bs corresponding to itself in the X direction. Each flow path component 60 extends along the Y direction. Specifically, each flow path component 60 has a plate-shaped bottom 65 with the Y direction as the length direction and the X direction as the width direction, and a side portion 68 protruding upward from both ends of the bottom 65 in the X direction. At the bottom 65 of each flow path component 60, a connecting hole 66 connected to the safety valve 76 is provided for each safety valve 76. In addition, in the figure, the connecting hole 66 is circular when viewed from above, but it can also be rectangular or the like.

[0056] like Figure 1 As shown, the cover body 30 is a plate-shaped component extending in the X direction and the Y direction, which seals the shell 80 from the upper side. The material of the cover body 30 is metal or the like. A flow path forming portion 36 is formed in the portion of the cover body 30 located above the flow path component 60. Thus, a flow path forming portion 36 is provided for each battery stack Bs. The upper surface of each flow path forming portion 36 protrudes upward and extends in the Y direction. Thus, the lower surface of each flow path forming portion 36 is recessed upward and extends in the Y direction. The space surrounded by the flow path forming portion 36 and the flow path component 60 constitutes a smoke exhaust flow path Sm. Thus, a smoke exhaust flow path Sm connected to the safety valve 76 is formed between the cover body 30 and each battery stack Bs.

[0057] More specifically, the portion of the cover 30 where the flow path forming portion 36 is provided is supported by the side portion 68 of the flow path member 60 . The smoke exhaust flow path Sm and the conductive member 50 are separated by the side portion 68 and the flow path forming portion 36 .

[0058] Figure 4 The heat conducting component 40 shown is arranged at Figure 5 On each conductive member 50 shown. Figure 4 Each heat-conducting component 40 shown is an insulator such as rubber or resin. Figure 5As shown in FIG. 1 , a locking protrusion 45 is provided on the lower surface of the heat conducting component 40. By locking the locking protrusion 45 with the locking recess 54 of the conductive component 50, each heat conducting component 40 is positioned on the conductive component 50 corresponding to itself. Figure 1 As shown, each heat conducting member 40 is disposed between the corresponding conductive member 50 and the cover 30 . The lower surface of each heat conducting member 40 abuts against the conductive member 50 , and the upper surface of each heat conducting member 40 abuts against the cover 30 .

[0059] In this embodiment, Figure 1 The jacket 20 shown is a water jacket. The jacket 20 covers the cover body 30 from the upper side. The material of the jacket 20 is metal or the like. The jacket 20 includes a top plate portion 22 extending in the X direction and the Y direction, a side plate portion 25 protruding downward from both ends of the top plate portion 22 in the X direction, and a protrusion 26 protruding outward from the lower end of the side plate portion 25 in the X direction. The protrusion 26 is joined to the upper surface of the housing 80 by friction stir welding or the like. Furthermore, the top plate portion 22 is joined to each flow path forming portion 36 in the cover body 30 by friction stir welding. By the above, cooling flow paths Co1, Co2, and Co3 are formed between the cover body 30 and the jacket 20.

[0060] Specifically, if Figure 3 As shown, the cooling channels Co1, Co2, and Co3 include a first channel Co1, a second channel Co2, and a third channel Co3. The first channel Co1 is formed closer to the X+ direction side than the channel forming portion 36 on the X+ side. The second channel Co2 is formed between the channel forming portion 36 on the X- side and the channel forming portion 36 on the X+ side. The third channel Co3 is formed closer to the X- direction side than the channel forming portion 36 on the X- side.

[0061] In the present embodiment, a water supply pipe (not shown) for supplying cooling water as the refrigerant Rf is connected to the end on the Y-direction side in the first flow path Co1. Furthermore, the end on the Y+direction side in the first flow path Co1 and the end on the Y+direction side in the second flow path Co2 are connected by a connecting pipe (not shown). Furthermore, the end on the Y-direction side in the second flow path Co2 and the end on the Y-direction side in the third flow path Co3 are connected by another connecting pipe (not shown). Furthermore, a drainage pipe is connected to the end on the Y+direction side in the third flow path Co3. Thus, the refrigerant Rf will flow through the first flow path Co1, the second flow path Co2, and the third flow path Co3 in sequence. However, instead of this, for example, the refrigerant Rf may also flow in parallel in the three cooling flow paths Co1, Co2, and Co3.

[0062] The configuration and effects of this embodiment are summarized below.

[0063] According to this embodiment, Figure 1 As shown, a plurality of battery stacks Bs are accommodated in a housing 80 arranged in the X direction. Therefore, the housing 80 becomes longer in the X direction. Moreover, the housing 80 does not have a partition that separates the battery stacks Bs from each other. Therefore, the jacket 20 cannot be joined to the partition. However, on the cover body 30, a flow path forming portion 36 that protrudes upward and extends in the Y direction is provided for each battery stack Bs. Rigidity is ensured by joining the jacket 20 to their flow path forming portions 36. Therefore, according to this embodiment, while a plurality of battery stacks Bs are accommodated in a housing 80 arranged in the X direction, the rigidity of the jacket 20 can also be ensured.

[0064] like Figure 1 As shown, the portion of the cover 30 where the flow path forming portion 36 is provided is supported by the side portion 68 of the flow path member 60. Therefore, the rigidity of the cover 30 can be ensured. The jacket 20 is joined to the cover 30. Therefore, the rigidity of the jacket 20 can also be ensured in this respect.

[0065] like Figure 1 As shown, the smoke exhaust flow path Sm is separated from the conductive member 50 by the side portion 68 of the flow path member 60 and the flow path forming portion 36. Therefore, when the contents of the battery cell 70 flow out from the safety valve 76, the side portion 68 of the flow path member 60 and the flow path forming portion 36 prevent the contents from contacting the conductive member 50 and causing a short circuit.

[0066] like Figure 4 As shown, conductive members 50 are provided on both sides of the upper surface of the battery stack Bs sandwiching the safety valve 76 in the X direction. Figure 1 As shown, the lower surface of each heat-conducting component 40 abuts against the conductive component 50, and the upper surface of each heat-conducting component abuts against the aforementioned cover. As a result, the heat of each battery cell 70 is dissipated from the electrodes p and n to the refrigerant Rf in the cooling flow paths Co1, Co2, and Co3 via the conductive component 50, the heat-conducting component 40, and the cover 30. Therefore, each battery cell 70 can be effectively cooled.

[0067] Figure 1 The jacket 20 shown is joined to the flow path forming portion 36 by friction stir welding. Therefore, the jacket 20 and the flow path forming portion 36 can be easily joined. By this joining, the rigidity of the jacket 20 can be effectively ensured.

[0068] [Other embodiments]

[0069] The above-described embodiments may be modified as follows, for example. Figure 1The housing 80 shown can accommodate only one battery stack Bs, or can accommodate three or more. In the case where the jacket 20 can be sufficiently simply and firmly joined to the cover body 30 by a method other than friction stir joining such as welding, the joining method can also be used. In the case where the heat dissipation performance can be sufficiently ensured even without the heat-conducting component 40, there can be no heat-conducting component 40. The refrigerant Rf can also be a liquid or gas other than water. When the refrigerant Rf is a gas, a fan or the like can be used to send air into the cooling flow paths Co1, Co2, and Co3.

[0070] Figure 4 The heat conducting component 40 shown may also be arranged in a manner spanning across a plurality of the conductive components 50. Figure 5 In the housing 80 shown, a plurality of parallel connection bodies may be connected in series, and each parallel connection body may have a predetermined number of battery cells 70 such as two or three.

[0071] exist Figure 5 In the embodiment, the engaging recess 54 of each conductive component 50 and the engaging protrusion 45 of each heat conductive component 40 extend in the X direction, but may also extend in the Y direction. Figure 5 On the contrary, the conductive member 50 is provided with an engaging protrusion, and the thermal conductive member 40 is provided with an engaging concave portion that fits with the protrusion.

[0072] Reference numerals

[0073] 20 Jacket

[0074] 30 Cover

[0075] 36 Flow path forming part

[0076] 40 Heat conducting components

[0077] 50 Conductive parts

[0078] 60 Flow path components

[0079] 65 Bottom of the flow path component

[0080] 68 Flow path component frontal side

[0081] 70 battery cells

[0082] 76 Safety valve

[0083] 80 Shell

[0084] 100 Battery Pack

[0085] Bs battery stack

[0086] Co1 first flow path (cooling flow path)

[0087] Co2 second flow path (cooling flow path)

[0088] Co3 third flow path (cooling flow path)

[0089] Sm exhaust flow path

[0090] X width direction

[0091] Y stacking direction

Claims

1. A battery pack, comprising: a plurality of battery cells; a housing that houses a plurality of battery laminates in which the battery cells are laminated in a predetermined lamination direction, arranged side by side in a width direction orthogonal to the lamination direction; and a lid that covers the housing from above; Each of the battery cells has a safety valve on its upper surface capable of discharging the gas inside; Among them, On the lid, for each of the battery laminates, there is provided a flow path forming portion that protrudes upward and extends in the lamination direction; A smoke exhaust flow path communicating with the safety valve is formed between each of the flow path forming portions and the battery laminate; The battery pack further includes a jacket that covers the lid from above; A cooling flow path for circulating a refrigerant is formed between the lid and the jacket, and the jacket is joined to each of the flow path forming portions.

2. The battery pack according to claim 1, Among them, A flow path component is mounted on the upper surface of the battery laminate; On both sides of the flow path component clamped in the width direction on the upper surface of each of the battery laminates, there are provided conductive components for electrically connecting the electrodes of the battery cells to each other; The flow path component includes a bottom portion extending in the lamination direction and side portions protruding upward from both ends in the width direction of the bottom portion; A communication hole communicating with the safety valve is provided in the bottom portion of the flow path component; The portion of the lid where the flow path forming portion is provided is supported by the side portion of the flow path component; The portion surrounded by the flow path component and the flow path forming portion is the smoke exhaust flow path; The smoke exhaust flow path and the conductive component are separated by the side portion of the flow path component and the flow path forming portion.

3. The battery pack according to claim 1 or 2, Among them, On both sides of the safety valve clamped in the width direction on the upper surface of each of the battery laminates, there are provided conductive components for electrically connecting the electrodes of the battery cells to each other; A heat conductive component is disposed between the conductive component and the lid; The lower surface of the heat conductive component abuts against the conductive component, and the upper surface of the heat conductive component abuts against the lid.

4. The battery pack according to claim 1 or 2, Among them, The jacket is joined to each of the flow path forming portions by friction stir welding.

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