Battery pack and battery assembly

Abstract

The invention provides a battery pack and a battery assembly, which can alleviate pressure rise in a case when a single battery is in thermal runaway. A battery pack (10) is provided with: a unit cell stack (30) in which a plurality of unit cells (40) having safety valves (44) are stacked; an exhaust passage (46) connected to the relief valve (44) and extending in the stacking direction of the plurality of unit cells (40); and a case (20) that houses the unit cell stack (30) and the exhaust passage (46). The case (20) is provided with: a pressure relief valve (13) which communicates with an open space outside the case (20) and the exhaust passage (46) and which is capable of discharging, to the open space, gas released from the safety valve (44) of the single cell (40); and a check valve (15) that communicates with the sealed space outside the housing (20) and that is capable of discharging gas into the sealed space.

Description

Technical Field

[0001] The present invention relates to a battery pack and a battery assembly including a single-cell stack formed by stacking a plurality of single cells. Background Art

[0002] In recent years, in order to ensure that more people have access to affordable, reliable, and sustainable modern energy, research and development related to secondary batteries that contribute to energy efficiency improvement have been underway.

[0003] With the electrification of vehicle drive sources, vehicles are equipped with batteries that supply power to motors and the like. A battery is formed, for example, by stacking a plurality of single cells. A single cell is provided with a valve for discharging high-temperature and high-pressure gas generated inside due to an abnormality or the like to the outside of the single cell (see, for example, Patent Documents 1 and 2).

[0004] In addition, Patent Document 2 describes a gas discharge structure of a battery module, which includes: a single-cell unit formed by stacking a plurality of single cells each having an explosion-proof valve; a module case that houses the single-cell unit; an internal pressure release portion that is disposed through the module case and releases gas accumulated inside to the outside; and a partition wall that is disposed between the single-cell unit and the internal pressure release portion.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2003-178740

[0008] Patent Document 2: Japanese Patent No. 5939307 Summary of the Invention

[0009] Problems to be Solved by the Invention

[0010] In Patent Document 2, although an internal pressure release portion is provided in the case, if gas is released from the explosion-proof valve of the unit into the case due to thermal runaway, the inside of the case temporarily becomes high pressure. In order to reduce the influence on the outside accompanying the pressure increase inside the case, a structure that can appropriately relieve the pressure increase inside the case is desired.

[0011] The present invention provides a battery pack and a battery assembly that can relieve the pressure increase inside the case during thermal runaway of a single cell. Furthermore, it contributes to improving energy efficiency.

[0012] Means for Solving the Problems

[0013] The present invention relates to a battery pack including:

[0014] a single-cell stack formed by stacking a plurality of single cells each having a safety valve;

[0015] An exhaust passage that connects the safety valves of the individual cells and extends in the stacking direction of the plurality of individual cells; and

[0016] A housing that houses the stacked body of individual cells and the exhaust passage, wherein

[0017] The housing is provided with:

[0018] A pressure release valve that communicates with the open space outside the housing and the exhaust passage and can discharge the gas released from the safety valve of the individual cell to the open space; and

[0019] A check valve that communicates with the closed space outside the housing and can discharge the gas to the closed space.

[0020] The present invention also relates to a battery assembly including:

[0021] A plurality of battery packs; and

[0022] A conductive component housing portion that liquid-tightly connects the plurality of battery packs and is provided with conductive components that electrically connect the plurality of battery packs, wherein

[0023] Each battery pack includes:

[0024] A stacked body of individual cells formed by stacking a plurality of individual cells having safety valves;

[0025] An exhaust passage that connects the safety valves of the individual cells and extends in the stacking direction of the plurality of individual cells; and

[0026] A housing that houses the stacked body of individual cells and the exhaust passage and is connected to the conductive component housing portion,

[0027] The housing is provided with:

[0028] A pressure release valve that communicates with the open space outside the housing and the exhaust passage and can discharge the gas released from the safety valve of the individual cell to the open space; and

[0029] A check valve that communicates with the conductive component housing portion and can discharge the gas to the conductive component housing portion.

[0030] Advantages of the Invention

[0031] According to the present invention, it is possible to mitigate the pressure rise inside the housing when an individual cell undergoes thermal runaway. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is an external perspective view of the battery pack 10.

[0033] Figure 2 is an exploded perspective view of the battery pack 10.

[0034] Figure 3 is an exploded perspective view of the single-cell stack 30.

[0035] Figure 4 is an external perspective view of the battery assembly 100.

[0036] Figure 5 is an external perspective view of the battery assembly 100 observed from the bottom side with the bottom cover 126 disassembled.

[0037] Figure 6 is an external perspective view of the central frame 120.

[0038] Figure 7 is an external perspective view of the bulging portion 22.

[0039] Figure 8 is Figure 7 a cross-sectional view taken along line A-A of

[0040] Figure 9 a diagram showing the situation where the gas generated during thermal runaway of the single cell 40 is discharged to the outside of the single-cell accommodation space 25 through the through-hole 93.

[0041] Figure 10 is a diagram showing the flow of gas inside the battery assembly 100 in the case of thermal runaway occurring in a certain battery pack 10.

[0042] Explanation of Reference Numerals

[0043] 10 Battery pack

[0044] 12 Seal

[0045] 13 Pressure relief valve

[0046] 15 Check valve

[0047] 151 One end side

[0048] 152 The other end side

[0049] 153 Bending portion

[0050] 20 Housing

[0051] 21 Housing main body

[0052] 23 Housing cover

[0053] 30 Single-cell stack

[0054] 40 Single cell

[0055] 42 Terminal part

[0056] 44 Safety valve

[0057] 46 Exhaust passage

[0058] 61 Output conductive member (second conductive member)

[0059] 85 Partition part (longitudinal wall part)

[0060] 88 Bottom wall part

[0061] 93 Through hole (opening part)

[0062] 100 Battery assembly

[0063] 125 Hollow area (conductive member accommodation part, sealed space)

[0064] 140 Bus bar unit (first conductive member). Detailed implementation mode

[0065] Hereinafter, an embodiment of the battery pack of the present invention will be described based on the drawings. In addition, in the following description, for convenience, a coordinate system composed of the front - rear direction, left - right direction, and up - down direction orthogonal to each other will be used for the description. In the drawings, the front is represented as Fr, the rear is represented as Rr, the left side is represented as L, the right side is represented as R, the upper side is represented as U, and the lower side is represented as D. However, these directions have nothing to do with the direction when the battery pack is mounted on the device. For example, when the battery pack is mounted on a vehicle, the up - down direction of the battery pack can be in the traveling direction of the vehicle when mounted, or can be in the vehicle width direction.

[0066] [Battery pack]

[0067] As Figure 1 and Figure 2 shown, in the battery pack 10, two single - cell stacks 30 are arranged in the box - shaped housing 20 in the front - rear direction. As Figure 3As shown, the single-cell stack 30 has a plurality of square single cells 40 stacked in the left-right direction, and an end plate 31 disposed on one side in the left-right direction (the left side in this embodiment), and they are temporarily fixed with a prescribed pressure by using a plate clamp 50. Additionally, a partition (not shown) may be disposed between adjacent single cells 40. The plate clamp 50 includes a rectangular lower restraint portion 51 surrounding the bottom surface of the single-cell stack 30, a rectangular upper restraint portion 52 surrounding the upper surface of the single-cell stack 30, and a pair of side restraint portions 53 sandwiching the single-cell stack 30 in the front-rear direction, and the lower restraint portion 51 and the pair of side restraint portions 53 are integrally formed. Additionally, it may be configured such that another end plate, partition, etc. are disposed on the other side in the left-right direction of the single-cell stack 30 (the right side in this embodiment) so that the single cells 40 do not directly contact the housing 20 on the other side. Additionally, the single-cell stack 30 may not be a structure in which a plurality of single cells 40 are restrained by the plate clamp 50, that is, it may be a structure in which a plurality of single cells 40 are directly stacked and disposed inside the housing 20.

[0068] The single cell 40 is, for example, a secondary battery such as a lithium-ion battery. On the upper surface of the single cell 40, there are provided: a pair of terminal portions 42 provided at both ends in the front-rear direction, which is a direction orthogonal to the stacking direction of the single cells 40; and a safety valve 44 provided at the central portion in the front-rear direction and disposed between the pair of terminal portions 42. The pair of terminal portions 42 includes a positive terminal and a negative terminal. For example, the positive terminal is connected to the negative terminal of an adjacent single cell 40 via a bus bar (not shown), and the negative terminal is connected to the positive terminal of an adjacent single cell 40 via a bus bar (not shown), whereby a plurality of single cells 40 are electrically connected in series. For example, in order to shorten the length of the bus bar, a plurality of single cells 40 may be stacked in an alternating flipped orientation in the front-rear direction.

[0069] The safety valve 44 is a rupture-type valve for preventing the rupture of the outer can when the internal pressure of the single cell 40 abnormally rises. When the internal pressure of the single cell 40 abnormally rises, the safety valve 44 ruptures, and the gas inside the single cell 40 is released to the outside. By disposing the safety valve 44 at the central portion in the front-rear direction of the single cell 40, even when a plurality of single cells 40 are stacked in an alternating flipped orientation in the front-rear direction, they can converge at the same position in the front-rear direction.

[0070] An exhaust passage 46 is provided in the single cell 40. The exhaust passage 46 connects the safety valves 44 of the plurality of single cells 40 and allows the gas released from the safety valve 44 to flow. For example, the exhaust passage 46 is constituted by a cover covering the safety valve 44. The exhaust passage 46 extends in the direction in which the safety valves 44 are arranged, that is, the stacking direction of the single cells 40, and guides the gas to a pressure release valve 13 described later.

[0071] Return Figure 2, the housing 20 includes a housing main body 21 with an upper opening and a housing cover 23 that covers the opening of the housing main body 21. The housing main body 21 has: a front wall portion 82 and a rear wall portion 84 that extend in the left-right direction; a left wall portion 86 that connects the left ends of the front wall portion 82 and the rear wall portion 84; a right wall portion 87 that connects the right ends of the front wall portion 82 and the rear wall portion 84; and a bottom wall portion 88. The space surrounded by the front wall portion 82, the rear wall portion 84, the left wall portion 86, and the right wall portion 87 constitutes a single-cell accommodation space 25 for accommodating the single-cell laminate 30.

[0072] An opening 86a that communicates the single-cell accommodation space 25 with the outside is provided in the left wall portion 86, and a pressure plate 28 is installed with a seal 16 (such as a rubber seal) interposed therebetween. By fixing the pressure plate 28 to the left wall portion 86, the pressure plate 28 contacts the end plate 31 of each single-cell laminate 30 from the opening 86a. The pressure plate 28 presses the end plate 31 inward, whereby the single-cell laminate 30 temporarily fixed with a prescribed pressure by the plate clamp 50 is further pressed in the stacking direction and held in the housing 20. The fixing of the pressure plate 28 to the left wall portion 86 can be a fixing based on welding such as friction stir welding or a bolt fixing. Thus, in the battery pack 10, a plurality of single cells 40 can be held in the housing 20 without modularization, and therefore the energy density and space efficiency can be improved.

[0073] In addition, as Figure 1 shown, two pressure release valves 13 that communicate with the single-cell accommodation space 25 are provided on the pressure plate 28. When the internal pressure of the single-cell accommodation space 25 abnormally rises due to gas generated from the safety valve 44 of the single cell 40, the pressure release valve 13 opens to release the gas in the housing 20 to the outside.

[0074] In addition, in front of and to the left of the front wall portion 82, a bulging portion 22 is formed so as to protrude further forward from the front wall portion 82. A space is formed inside the bulging portion 22, a first opening 91 is provided on the front surface, and a second opening 92 is also provided on the upper surface. A terminal block 60 for connecting and taking out the conductive member 70 is provided in the internal space of the bulging portion 22, constituting an output terminal accommodation space 27. On the terminal block 60, the terminal portion (output terminal) of the output conductive member 61 extending from the single battery accommodation space 25 to the output terminal accommodation space 27 is electrically connected to the terminal portion of the take-out conductive member 70 that enters the output terminal accommodation space 27 from the first opening 91. The output conductive member 61 includes a positive-side bus bar 62 and a negative-side bus bar 63, and the positive-side bus bar 62 and the negative-side bus bar 63 extend from the positive-side output terminal and the negative-side output terminal of two single battery stacks 30 electrically connected in series, respectively. The take-out conductive member 70 includes a positive-side bus bar 72 and a negative-side bus bar 73, and the positive-side bus bar 72 and the negative-side bus bar 73 are connected to, for example, external positive and negative terminals, respectively.

[0075] In this way, inside the housing 20, there are provided: a single battery accommodation space 25 that accommodates two single battery stacks 30; and an output terminal accommodation space 27 that is disposed in front of and to the left of the single battery accommodation space 25 and is connected to the take-out conductive member 70. In addition, the number of single battery stacks 30 accommodated in the single battery accommodation space 25 may be one or three or more.

[0076] The height of the region in the front wall portion 82 that separates the single battery accommodation space 25 and the output terminal accommodation space 27 (hereinafter, this portion will be referred to as the partition portion 85) is lower than other regions. A gap is provided between the upper end of the partition portion 85 and the housing cover 23, and this gap forms a through-hole 93 through which the output conductive member 61 can pass (see Figure 8 ). The output conductive member 61 has an inverted L shape, one end side extends forward from the through-hole 93 to the output terminal accommodation space 27, and the other end side extends downward and is fixed to the terminal block 60 provided in the output terminal accommodation space 27.

[0077] In addition, as Figure 1 shown, a signal line connector 67 is provided in the output terminal accommodation space 27. The signal line connector 67 is connected to a signal line via a through-hole that communicates the single battery accommodation space 25 and the output terminal accommodation space 27.

[0078] A housing cover 23 is mounted on the upper surface of the housing body 21 with a first seal 11 (such as a rubber seal) interposed therebetween. The housing cover 23 is fixed to the upper surface of the housing body 21 by welding such as friction stir welding. By sealing the single cell accommodation space 25 from the outside, entry of foreign matter into the single cell accommodation space 25 can be suppressed, and deterioration of the single cell 40 can be suppressed.

[0079] The battery pack 10 configured in this way does not include auxiliary devices such as a junction box for accommodating contactors, fuses, etc., and an ECU. Therefore, in the case of using the battery pack 10 alone, the junction box and / or the ECU can be connected to the battery pack 10. In addition, in the case of using a plurality of battery packs 10, the battery packs 10 can also be electrically connected to each other through a distribution box, and the junction box and / or the ECU can be connected to the distribution box. In addition, the junction box and / or the ECU can be incorporated in the distribution box, and the plurality of battery packs 10 can be connected to the junction box and / or the ECU in the distribution box.

[0080] Next, with reference to Figures 4 to 6 , a mounting structure of the battery pack in which four battery packs 10 are mounted under the floor of the vehicle will be described. In the following description, the front-rear direction, the left-right direction (vehicle width direction), and the up-down direction are defined based on the vehicle.

[0081] In this mounting structure, as Figure 4 shown, a central frame 120 extending in the vehicle width direction is fixed between a left frame 110L and a right frame 110R extending in the front-rear direction of the vehicle. In addition, the two battery packs 10 are arranged side by side in the space in front of the central frame 120, and the two battery packs 10 are arranged side by side in the space behind the central frame 120. The four battery packs 10 are fixed to and supported by the left frame 110L, the right frame 110R, and the central frame 120. Hereinafter, this structure will be referred to as a battery pack assembly 100.

[0082] [Battery pack assembly]

[0083] In the battery pack assembly 100, the two front battery packs 10 are arranged such that the bulging portion 22 is located at the rear and to the right, and the two rear battery packs 10 are arranged such that the bulging portion 22 is located at the front and to the left. That is, the two front battery packs 10 and the two rear battery packs 10 are arranged in a state rotated by 180° so that the bulging portions 22 face each other in the front-rear direction with the central frame 120 interposed therebetween.

[0084] As Figure 6 shown, the central frame 120 of the battery pack assembly 100 is a hollow body having a rectangular cross section, and is fastened to the left frame 110L and the right frame 110R by flange portions 127 extending in the front-rear direction formed at the left and right ends.

[0085] On the front surface 121 of the central frame 120, two front communication holes 121a are formed, which are respectively communicated with the first opening 91 of the protruding portion 22 of the battery pack 10 formed in the front. Similarly, on the rear surface 122 of the central frame 120, two rear communication holes 122a are formed, which are respectively communicated with the first opening 91 of the protruding portion 22 of the battery pack 10 formed in the rear. The front communication holes 121a and the rear communication holes 122a are offset in the vehicle width direction. That is, the center positions of the front communication holes 121a in the vehicle width direction and the center positions of the rear communication holes 122a in the vehicle width direction are offset in the vehicle width direction.

[0086] Around the front communication holes 121a and the rear communication holes 122a, fastening portions 123 for liquid-tightly fastening the corresponding battery packs 10 are respectively provided. For example, by bolt fastening, each battery pack 10 is fixed to the central frame 120. The central frame 120 has fastening portions 123 on the front surface 121 and the rear surface 122 respectively, and the front surface 121 and the rear surface 122 protrude upward and downward, so that in the cross section cut along the front-rear direction, it has a high-rigidity cross-sectional shape like an H-beam.

[0087] The extraction conductive member 70 enters the hollow region 125 of the central frame 120 from the output terminal accommodation space 27 formed in the protruding portion 22 of each battery pack 10 through the first opening 91. As Figure 5 shown, a bus bar unit 140 is arranged in the hollow region 125 of the central frame 120. The bus bar unit 140 includes, for example, a plurality of connecting bus bars, and electrically connects four battery packs 10 in series, for example. The central frame 120 is an example of the above-mentioned distribution box. In addition, the hollow region 125 of the central frame 120 corresponds to the "sealed space" and "conductive member accommodation portion" of the present invention.

[0088] On the back surface of the central frame 120, a bottom surface opening 124 is provided, and the bottom surface opening 124 is liquid-tightly closed by a bottom surface cover 126 with a sealing member (not shown) interposed therebetween. The bottom surface opening 124 of the central frame 120 is liquid-tightly closed by the bottom surface cover 126, and the communication holes 121a and 122a of the central frame 120 are liquid-tightly fastened to the first openings 91 of the respective battery packs 10, so that moisture is restricted from entering the output terminal accommodation space 27 of the battery pack 10 and the hollow region 125 of the central frame 120 from the outside. In the state where the bottom surface cover 126 is removed, the extraction conductive members 70 extending from the respective battery packs 10 to the hollow region 125 of the central frame 120 are fastened to the bus bar unit 140 from the bottom surface opening 124.

[0089] The battery assembly 100 configured in this way is fixed to the frame member of the vehicle by a pair of central support portions 128 provided on the central frame 120 and side support portions 111 provided on the left frame 110L and the right frame 110R, and is disposed under the floor of the vehicle.

[0090] [Gas discharge structure]

[0091] In the case where some abnormality, such as an internal short circuit, occurs in the single battery 40, the single battery 40 may undergo abnormal heat generation, i.e., thermal runaway, and high-temperature and high-pressure gas is generated inside the single battery 40. When the pressure of the gas generated inside the single battery 40 rises above a specified value, the safety valve 44 ruptures, and the gas is released to the outside of the single battery 40, i.e., the inside of the housing 20.

[0092] In order to discharge the gas filled inside the housing 20 during thermal runaway to the outside of the housing 20, the aforementioned pressure release valve 13 is provided in the battery pack 10. However, since the single battery laminate 30 is pressed by the pressure plate 28 and tightly arranged in the housing 20, the gap between the single battery laminate 30 and the housing 20 is small, and the inside of the housing 20 easily becomes high pressure when the gas is released from the safety valve 44. Therefore, in the battery pack 10, it is preferable to further provide a structure for alleviating the pressure rise inside the housing 20 in addition to the pressure release valve 13.

[0093] In the present embodiment, as Figures 7 to 9 shown, the battery pack 10 further includes a check valve 15. The check valve 15 communicates with the hollow region 125 of the central frame 120 on the outside of the housing 20, and is configured to be able to discharge the gas filled in the single battery accommodation space 25 to the hollow region 125.

[0094] When the pressure in the single battery accommodation space 25 rises due to the thermal runaway of the single battery 40, the pressure release valve 13 opens, and the gas filled in the single battery accommodation space 25 is discharged to the open space outside the housing 20, releasing the pressure in the single battery accommodation space 25. Moreover, the check valve 15 also opens, and the gas is discharged to the hollow region 125 of the central frame 120, which is a closed space, alleviating the pressure rise in the single battery accommodation space 25 at the initial stage of the thermal runaway of the single battery 40. In this way, when the single battery 40 undergoes thermal runaway, the battery pack 10 opens at two places, i.e., the pressure release valve 13 and the check valve 15, so that the pressure can be appropriately released, and the pressure rise inside the housing 20 can be alleviated. Therefore, the impact during thermal runaway can be alleviated, and the influence on the outside due to the pressure rise of the housing 20 can be suppressed.

[0095] In addition, since the hollow region 125 is a sealed space, after a certain amount of gas flows into the hollow region 125 (i.e., after the initial stage of thermal runaway), the flow of gas into the hollow region 125 converges. After the initial stage of thermal runaway, substances such as the electrolyte and electrodes of the single cell 40 (hereinafter also referred to as single cell contents) may be released from the safety valve 44. However, due to the convergence of the gas flow into the hollow region 125, the single cell contents do not flow into the hollow region 125 but are guided to the pressure release valve 13 and discharged to the outside of the housing 20. Therefore, it is possible to suppress a short circuit in the bus bar unit 140 in the hollow region 125 due to the single cell contents.

[0096] Moreover, the check valve 15 has a function of restricting the inflow of gas from the outside of the housing 20. Therefore, as Figure 10 shown, for example, even when the battery pack 10 disposed on the front side and the right side in the battery assembly 100 undergoes thermal runaway and gas is released from the battery pack 10 to the hollow region 125 of the central frame 120, the check valve 15 prevents the gas from flowing into the other three battery packs 10. Therefore, it is possible to suppress the cascading thermal runaway of other battery packs 10 due to thermal runaway occurring in a certain battery pack 10.

[0097] Hereinafter, an example of the specific structure of the check valve 15 will be described. In addition, the structure of the check valve 15 is not limited to this example, and various structures can be adopted.

[0098] As Figure 8 shown, the check valve 15 of the present embodiment is provided on the housing 20 so as to cover the through-hole 93 through which the output conductive member 61 passes. The check valve 15 is provided outside the single cell accommodation space 25, specifically in the output terminal accommodation space 27, and covers the through-hole 93 from the output terminal accommodation space 27 side. The through-hole 93 and the check valve 15 are arranged to extend in the left-right direction along the partition portion 85.

[0099] Normally, the check valve 15 covers a part of the through-hole 93 and the output conductive member 61 with a seal 12 (such as a foam seal), and together with the housing cover 23, seals the single cell accommodation space 25. On the other hand, as Figure 9 shown, when the pressure in the single cell accommodation space 25 rises due to thermal runaway of the single cell 40, the check valve 15 opens, discharges the gas from the through-hole 93 to the hollow region 125 of the central frame 120, and releases the pressure in the single cell accommodation space 25.

[0100] More specifically, the check valve 15 is a plate member having a substantially L-shaped configuration. One end side 151 of the check valve 15 extends in the horizontal direction and is fixed to the lower surface of the housing cover 23 outside the single battery accommodation space 25. The one end side 151 can be fixed to the housing cover 23 by fastening members such as bolts, or can be fixed to the housing cover 23 by welding such as friction stir welding.

[0101] The other end side 152 of the check valve 15 extends in the vertical direction and covers the through-hole 93 with the seal member 12 interposed therebetween. The other end side 152 is disposed in close contact with the partition portion 85 and the output conductive member 61 with the seal member 12 interposed therebetween. Thus, the check valve 15 and the seal member 12 together cover the through-hole 93 through which the output conductive member 61 passes, and thus the airtightness of the single battery accommodation space 25 can be ensured. In addition, it is also possible to suppress foreign matter from entering the single battery accommodation space 25 through the through-hole 93.

[0102] As Figure 9 shown, when the single battery accommodation space 25 is filled with gas due to thermal runaway of the single battery 40 and the pressure in the single battery accommodation space 25 rises, the check valve 15 is deformed and the through-hole 93 is opened. The check valve 15 has a bent portion 153 between the one end side 151 and the other end side 152, and rotates around the bent portion 153 under the pressure of the gas to discharge the gas to the hollow region 125 of the central frame 120. In other words, the check valve 15 is configured as a damper in which the one end side 151 is fixed and the other end side 152 rotates around the bent portion 153.

[0103] Thus, the check valve 15 covers the through-hole 93 through which the output conductive member 61 passes to ensure the airtightness of the single battery accommodation space 25, and can discharge the gas to the hollow region 125 of the central frame 120 to release the pressure when the pressure in the single battery accommodation space 25 rises. In addition, the check valve 15 is a plate member having a substantially L-shaped configuration and can be deformed relatively easily, that is, can rotate around the bent portion 153. Therefore, the pressure in the single battery accommodation space 25 can be released without breaking the housing main body 21 and the housing cover 23.

[0104] In addition, the pressure release valve 13 is disposed at a position in the stacking direction with respect to the single battery laminate 30, specifically, on the left wall portion 86. In contrast, the check valve 15 is disposed at a position in a direction orthogonal to the stacking direction with respect to the single battery laminate 30, specifically, in the front. That is, since the pressure release valve 13 and the check valve 15 are disposed in different directions when viewed from the single battery laminate 30, the flow of the single battery content toward the check valve 15 can be suppressed when it is guided toward the pressure release valve 13 in the stacking direction.

[0105] In addition, a pair of terminal portions 42 of each single cell 40 are provided at both end portions (i.e., the front portion and the rear portion) in the direction orthogonal to the stacking direction with the safety valve 44 therebetween. Therefore, when the content of the single cell is guided along the stacking direction to the pressure release valve 13, it is possible to suppress the content of the single cell from adhering to the terminal portion 42 and causing a short circuit.

[0106] In addition, since the check valve 15 is provided in the direction orthogonal to the stacking direction with respect to the single cell stack 30, when the content of the single cell is guided along the stacking direction to the pressure release valve 13, it is possible to suppress the content of the single cell from adhering to the output conductive member 61 and the extraction conductive member 70 provided near the check valve 15 and causing a short circuit.

[0107] In addition, the through port 93 and the check valve 15 are provided to extend in the left - right direction. Therefore, the exhaust port when discharging gas to the hollow region 125 can be made wider. Thus, the pressure in the single cell accommodation space 25 can be sufficiently released.

[0108] As described above, one embodiment of the present invention has been described with reference to the drawings, but the present invention is of course not limited to this embodiment. Those skilled in the art should understand that various modification examples or correction examples can obviously be conceived within the scope described in the technical solution, and these modification examples or correction examples also of course belong to the technical scope of the present invention. In addition, within the scope not departing from the gist of the invention, the constituent elements in the above - described embodiment can be arbitrarily combined.

[0109] For example, in the above - described embodiment, the battery assembly 100 is composed of a total of four battery packs 10, two in each of the front, rear, left, and right directions, but it is not limited thereto. It may also be composed of a total of two battery packs 10, one in each of the front and rear directions, or may be configured with two or more battery packs 10 in the front - rear direction and two or more battery packs 10 in the left - right direction.

[0110] In addition, in the above - described embodiment, the check valve 15 communicates with the hollow region 125 of the central frame 120 in which the bus bar unit 140 is arranged, but it is not limited thereto. For example, the check valve 15 may also communicate with a closed space of an electrical device other than the bus bar unit 140. In addition, for example, when using the battery pack 10 as a single unit instead of the battery assembly 100, a box or a tank constituting the closed space may be provided to communicate with the first opening 91, and the check valve 15 may communicate with this closed space.

[0111] At least the following matters are described in this specification. In the parentheses, corresponding constituent elements, etc. in the above - described embodiment are shown as an example, but are not limited thereto.

[0112] (1) A battery pack (battery pack 10), comprising:

[0113] A single cell laminate (single cell laminate 30) formed by laminating a plurality of single cells (single cell 40) each having a safety valve (safety valve 44);

[0114] An exhaust passage (exhaust passage 46) that connects the safety valves of the respective single cells and extends in the lamination direction of the plurality of single cells; and

[0115] A housing (housing 20) that houses the single cell laminate and the exhaust passage, wherein

[0116] The housing is provided with:

[0117] A pressure release valve (pressure release valve 13) that communicates with the open space outside the housing and the exhaust passage and can discharge the gas released from the safety valve of the single cell to the open space; and

[0118] A check valve (check valve 15) that communicates with the closed space (hollow region 125) outside the housing and can discharge the gas to the closed space.

[0119] According to (1), since the housing is provided with a check valve communicating with the closed space, when high-pressure gas is generated from the safety valve of the single cell due to thermal runaway, the check valve can be opened at the initial stage of thermal runaway to release the pressure inside the housing, and the pressure rise inside the housing can be alleviated. In addition, after the gas flows into the closed space, the flow of the gas converges towards the check valve, so that the gas and the single cell contents that may be generated together with the gas can be discharged to the outside of the housing through the pressure release valve communicating with the open space.

[0120] (2) The battery pack according to (1), wherein

[0121] The position of the pressure release valve with respect to the single cell laminate in the lamination direction,

[0122] The position of the check valve with respect to the single cell laminate in a direction orthogonal to the lamination direction.

[0123] According to (2), it is possible to suppress the flow of the single cell contents that may be released from the safety valve of the single cell due to thermal runaway or the like towards the check valve when being guided towards the pressure release valve.

[0124] (3) The battery pack according to (2), wherein

[0125] The closed space is a conductive component housing portion (hollow region 125) in which a first conductive component (bus bar unit 140) is disposed, and the first conductive component (bus bar unit 140) electrically connects the battery pack to other battery packs.

[0126] According to (3), it is possible to discharge gas from the check valve to the conductive component housing portion serving as an enclosed space at the initial stage of thermal runaway, and release the pressure inside the housing to the conductive component housing portion. In addition, different from the pressure release valve, the check valve is provided in a direction orthogonal to the stacking direction with respect to the single battery laminate, so that it is possible to further suppress the flow of the single battery content into the conductive component housing portion.

[0127] (4) The battery pack according to (3), wherein

[0128] Each single battery has the safety valve provided at the central portion in a direction orthogonal to the stacking direction, and terminal portions (terminal portions 42) provided at both end portions in a direction orthogonal to the stacking direction.

[0129] According to (4), since the terminal portions of each single battery are provided at both end portions in a direction orthogonal to the stacking direction, when the single battery content released from the safety valve due to thermal runaway is guided to the pressure release valve, it is possible to suppress its flow to the terminal portions of each single battery and cause a short circuit.

[0130] (5) The battery pack according to (4), wherein

[0131] The battery pack further includes a second conductive component (output conductive component 61) that electrically connects the terminal portion to the first conductive component disposed in the conductive component housing portion.

[0132] The check valve is provided near the second conductive component.

[0133] According to (5), the single battery content released from the safety valve due to thermal runaway does not flow to the check valve but is guided to the pressure release valve, so that it is possible to suppress the single battery content from flowing into the second conductive component provided at a position close to the check valve and causing a short circuit.

[0134] (6) The battery pack according to (5), wherein

[0135] The housing has:

[0136] A housing main body (housing main body 21) having a bottom wall portion (bottom wall portion 88) and a vertical wall portion (partition wall portion 85) erected from the bottom wall portion; and

[0137] A housing cover (housing cover 23) that covers the housing main body from above.

[0138] An opening portion (through hole 93) is provided between the vertical wall portion and the housing cover, and the second conductive component passes through the opening portion from the terminal portion toward the conductive component housing portion.

[0139] The check valve is arranged to cover the opening via a seal (seal 12).

[0140] According to (6), the check valve and the seal cover the opening through which the second conductive member passes, seal the housing, and can open the opening to release the pressure inside the housing in the case of thermal runaway of a single cell.

[0141] (7) The battery pack according to any one of (1) to (6), wherein

[0142] The check valve is a plate member having a substantially L-shaped configuration, the plate member covers the opening (through hole 93) that communicates the inside of the housing with the sealed space, one end side (one end side 151) of the plate member is fixed to the housing, and the other end side (the other end side 152) covers the opening via a seal (seal 12).

[0143] When the gas is released from the safety valve of the single cell, the other end side rotates around a bent portion (bent portion 153) provided between the one end side and the other end side.

[0144] According to (7), the check valve and the seal cover the opening communicating with the sealed space and the inside of the sealed housing, and can open the opening to release the pressure inside the housing in the case of thermal runaway of a single cell.

[0145] (8) The battery pack according to any one of (1) to (7), wherein

[0146] The single cell laminate is pressed against the housing in the stacking direction of the plurality of single cells and is housed in the housing.

[0147] According to (8), even in a battery pack in which the single cell laminate is pressed and tightly housed in the housing, the pressure rise inside the housing can be appropriately suppressed by the check valve.

[0148] (9) A battery assembly (battery assembly 100) includes:

[0149] A plurality of battery packs (battery pack 10); and

[0150] A conductive member housing portion (hollow region 125) that liquid-tightly connects the plurality of battery packs and is provided with a conductive member (bus bar unit 140) that electrically connects the plurality of battery packs, wherein

[0151] Each battery pack has:

[0152] A single cell laminate (single cell laminate 30) formed by stacking a plurality of single cells (single cell 40) each having a safety valve (safety valve 44);

[0153] An exhaust passage (exhaust passage 46) that connects the safety valves of the individual cells and extends in the stacking direction of the plurality of individual cells; and

[0154] A housing (housing 20) that houses the stacked body of individual cells and the exhaust passage and is connected to the conductive member housing portion,

[0155] In the housing are provided:

[0156] A pressure release valve (pressure release valve 13) that communicates with the open space outside the housing and the exhaust passage and can discharge the gas released from the safety valve of the individual cell to the open space; and

[0157] A check valve (check valve 15) that communicates with the conductive member housing portion and can discharge the gas to the conductive member housing portion.

[0158] According to (9), a check valve communicating with the conductive member housing portion which is a closed space is provided in the housing. Therefore, when high-pressure gas is generated from the safety valve of the individual cell due to thermal runaway, the gas can be discharged to the conductive member housing portion through the check valve at the initial stage of gas generation to relieve the pressure rise in the housing. In addition, due to the airtightness of the conductive member housing portion, after the gas flows into the conductive member housing portion, the flow of the gas converges to the check valve. Therefore, the gas and the content of the individual cell that may be generated together with the gas can be discharged to the outside of the housing through the pressure release valve communicating with the open space.

Claims

1. A battery pack comprising: A single cell stack, which is formed by stacking a plurality of single cells with safety valves; an exhaust passage connecting the safety valves of the respective single cells and extending in a stacking direction of the plurality of single cells; and a housing that accommodates the single cell stack and the exhaust passage, wherein: The housing is provided with: a pressure release valve communicating with an open space outside the housing and the exhaust passage, capable of discharging gas released from the safety valve of the battery cell into the open space; as well as The check valve is communicated with the sealed space outside the housing and is capable of discharging the gas into the sealed space.

2. The battery pack according to claim 1, wherein: The pressure release valve is provided at a position in the stacking direction relative to the single cell stack. The check valve is provided at a position in a direction perpendicular to the stacking direction with respect to the single cell stack.

3. The battery pack according to claim 2, wherein: The sealed space is a conductive member storage portion in which a first conductive member is disposed, and the first conductive member electrically connects the battery pack to another battery pack.

4. The battery pack according to claim 3, wherein: Each of the single cells has the safety valve provided at a center portion in a direction perpendicular to the stacking direction, and terminal portions provided at both end portions in a direction perpendicular to the stacking direction.

5. The battery pack according to claim 4, wherein: The battery pack further includes a second conductive member that electrically connects the terminal portion to the first conductive member disposed in the conductive member storage portion. The check valve is disposed near the second conductive component.

6. The battery pack according to claim 5, wherein: The housing has: a housing body having a bottom wall portion and a vertical wall portion erected from the bottom wall portion; and a housing cover covering the housing body from above, An opening is provided between the vertical wall and the housing cover, and the second conductive member passes through the opening from the terminal portion toward the conductive member storage portion. The check valve is provided so as to cover the opening portion via a seal.

7. The battery pack according to any one of claims 1 to 6, wherein: The check valve is a substantially L-shaped plate member, the plate member covers an opening that connects the inner side of the housing with the enclosed space, one end of the plate member is fixed to the housing, and the other end of the plate member covers the opening via a seal. When the gas is released from the safety valve of the single cell, the other end side rotates around a curved portion provided between the one end side and the other end side.

8. The battery pack according to any one of claims 1 to 6, wherein: The cell stack is pressed toward the case in a stacking direction of the plurality of cells and is accommodated in the case.

9. A battery assembly comprising: Multiple battery packs; as well as A conductive member storage portion connects the plurality of battery packs in a liquid-tight manner and is provided with a first conductive member that electrically connects the plurality of battery packs, wherein: Each battery pack has: A single cell stack, which is formed by stacking a plurality of single cells with safety valves; an exhaust passage connecting the safety valves of the respective single cells and extending in a stacking direction of the plurality of single cells; and a housing that accommodates the cell stack and the exhaust duct and is connected to the conductive member housing portion; The housing is provided with: a pressure release valve communicating with an open space outside the housing and the exhaust passage, capable of discharging gas released from the safety valve of the battery cell into the open space; as well as A check valve is communicated with the conductive member housing portion and is capable of discharging the gas to the conductive member housing portion.

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