Battery pack

Abstract

A battery pack is provided with: a plurality of battery cells; a housing body; a cap cover forming a space in which the plurality of battery cells are accommodated together with the case main body; a plate member disposed between the plurality of battery cells and the cover in the space; and a gasket sandwiched between the housing main body and the cover. A plurality of battery cells are arranged in a frame to constitute a cell assembly, the frame having a rectangular shape in which a second direction is a long side direction and a third direction orthogonal to the second direction is a short side direction when viewed in a first direction orthogonal to the top surface of the exterior body facing the panel member. The plate member has an inclined portion, and the inclined portion is inclined such that the distance between the top surface of the exterior body and the inclined portion in the first direction becomes smaller as the distance approaches the end portion of the cell assembly in the third direction.

Description

Technical Field

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

[0002] For example, International Publication No. 2020 / 189590 discloses a battery pack comprising: a secondary battery; a frame that accommodates the secondary battery; and a plate-shaped reinforcement portion that extends from one end to the other end of the frame in the long side direction and is arranged in the height direction of the secondary battery to reinforce the frame.

[0003] Japanese Patent Application Publication No. 2021-535556 discloses a battery pack including: a single cell; a first plate and a second plate connected to the upper surface and the lower surface of the single cell, respectively; and a heat transfer plate provided between the single cell and the first plate. Summary of the invention

[0004] In the battery pack disclosed in the above-mentioned International Publication No. 2020 / 189590, the frame (housing) containing the secondary battery is composed of a rectangular box-shaped main body with an open top and a cover covering the opening of the main body. In such a battery pack, when high-pressure gas is ejected from the battery cell when the battery is abnormal, there is a concern that gas will leak from the main body and the cover. In addition, there is a concern that the cover will be damaged due to the collision of the gas ejected from the battery cell with the cover.

[0005] Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a battery pack that can more reliably prevent gas leakage and cover damage.

[0006] [1] A battery pack, wherein the battery pack comprises: a plurality of battery cells; a casing body having an opening; a cover, the cover being mounted on the casing body in a manner to close the opening and forming a space for accommodating the plurality of battery cells together with the casing body; a plate member, the plate member being made of metal or ceramic and disposed between the plurality of battery cells and the cover in the space; and a gasket, the gasket being made of metal or ceramic and being clamped by the casing body and the cover, wherein the battery cells comprise: an outer casing, the outer casing including a top surface facing the plate member and accommodating an electrode body and an electrolyte; and a gas outflow valve, which allows gas to flow out from the interior of the outer casing through the top surface to the space when the pressure inside the outer casing becomes higher than a specified value. The plurality of battery cells are arranged in a frame to form a cell assembly. The frame is in a rectangular shape in which the second direction becomes the long side direction and the third direction orthogonal to the second direction becomes the short side direction when viewed along a first direction orthogonal to the top surface. The plate member has an inclined portion, and the inclined portion is inclined in such a manner that the distance between the top surface in the first direction and the inclined portion becomes smaller as it approaches the end of the cell assembly in the third direction.

[0007] According to the battery pack constructed in this way, the gas can be more reliably prevented from leaking from between the outer shell body and the cover by a gasket made of metal or ceramic. Furthermore, by blocking the gas generated from the battery cell with a plate member made of metal or ceramic, damage to the cover can be prevented. In this case, the gas blocked by the plate member is guided toward the end of the monomer assembly in the third direction by the inclined portion. Since the length of the monomer assembly in the third direction is smaller than the length of the monomer assembly in the second direction, the gas can be quickly retreated from between the top surface and the cover, and damage to the cover can be more reliably prevented.

[0008] [2] A battery pack as described in [1], wherein the battery cell is square, a plurality of the battery cells are stacked in a row in the second direction, and a distance between the top surface in the first direction and the inclined portion decreases as the distance from the gas outflow valve in the third direction increases.

[0009] According to the battery pack configured in this manner, the gas from the gas outflow valve blocked by the plate member can be efficiently guided toward the end of the cell assembly in the third direction by the inclined portion.

[0010] [3] A battery pack as described in [1] or [2], wherein the battery pack further comprises a duct, which is arranged opposite to the monomer assembly in the third direction to form a gas flow path connected to the space to discharge the gas from the space.

[0011] According to the battery pack structured in this way, the gas that has escaped from between the top surface and the cover is discharged from the space through the duct, thereby more reliably preventing the cover from being damaged.

[0012] [4] The battery pack according to any one of [1] to [3], wherein the plate member and the gasket are integrally formed from a metal or ceramic plate material.

[0013] According to the battery pack structured in this way, the structure of the battery pack can be simplified, and leakage of gas and damage to the cover can be prevented.

[0014] The foregoing and other objects, features, configurations and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a perspective view showing a battery pack according to Embodiment 1 of the present invention.

[0016] Figure 2 It is shown Figure 1 Exploded assembly diagram of the battery pack in .

[0017] Figure 3 It is a perspective view showing a battery cell.

[0018] Figure 4 is Figure 1 A cross-sectional view of the battery pack is schematically shown when viewed in the direction of arrows along line IV-IV in FIG.

[0019] Figure 5 It is shown Figure 4 A cross-sectional view of a first variant of the battery pack.

[0020] Figure 6 It is shown Figure 4 A cross-sectional view of a second variant of the battery pack.

[0021] Figure 7 It is shown Figure 4 A cross-sectional view of a third variant of the battery pack.

[0022] Figure 8 This is a cross-sectional view showing a battery pack according to Embodiment 2 of the present invention.

[0023] Fig. 9 It shows the composition Figure 8 A top view of the battery pack's monomer assembly.

[0024] Fig.10 It is shown Figure 8 A cross-sectional view of a modified example of the battery pack.

[0025] Fig.11 It shows the composition Fig.10 A top view of the battery pack's monomer assembly. DETAILED DESCRIPTION

[0026] Embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings referred to below, the same or corresponding components are denoted by the same reference numerals.

[0027] (Implementation Method 1)

[0028] Figure 1 This is a perspective view showing a battery pack according to Embodiment 1 of the present invention. Figure 2 It is shown Figure 1 Exploded assembly diagram of the battery pack in . Figure 3 It is a perspective view showing a battery cell. Figure 4 is Figure 1 A cross-sectional view of the battery pack is schematically shown when viewed in the direction of arrows along line IV-IV in FIG.

[0029] Reference Figures 1 to 4 The battery pack 100 can be used as a driving power source for vehicles such as hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV) or pure electric vehicles (BEV).

[0030] In this specification, for the convenience of explaining the structure of the battery pack 100, the axis extending in the horizontal direction in the stacking direction of the plurality of battery cells 11 described later is referred to as the "Y axis", the axis extending in the horizontal direction in a direction orthogonal to the Y axis is referred to as the "X axis", and the axis extending in the vertical direction is referred to as the "Z axis". Figure 4 As shown, the battery pack 100 has a substantially symmetrical structure with respect to an imaginary plane 110 parallel to the Y-axis-Z-axis plane.

[0031] The battery pack 100 has a plurality of battery cells 11. The plurality of battery cells 11 are stacked in the Y-axis direction. The plurality of battery cells 11 are stacked in a row in the Y-axis direction. The battery cells 11 are composed of lithium-ion batteries. The battery cells 11 are square and have a rectangular thin plate shape. The plurality of battery cells 11 are stacked in such a way that the Y-axis direction becomes the thickness direction of the battery cells 11.

[0032] The battery cell 11 has an outer casing 12. The outer casing 12 is composed of a rectangular parallelepiped frame, and forms the appearance of the battery cell 11. The outer casing 12 accommodates an electrode assembly and an electrolyte solution.

[0033] The exterior body 12 has a pair of first side surfaces 14 ( 14 j , 14 k ), a pair of second side surfaces 13 ( 13 j , 13 k ), a top surface 15 , and a bottom surface 16 .

[0034] The first side surface 14 is composed of a plane orthogonal to the X-axis. The first side surface 14 is parallel to the Y-axis direction which is the stacking direction of the battery cells 11. The first side surface 14j and the first side surface 14k face opposite sides in the X-axis direction. The second side surface 13 is composed of a plane orthogonal to the Y-axis. The second side surface 13 has the largest area among the multiple side surfaces of the outer casing 12. The second side surface 13j and the second side surface 13k face opposite sides in the Y-axis direction. Each of the top surface 15 and the bottom surface 16 is composed of a plane orthogonal to the Z-axis. The top surface 15 faces upward. The bottom surface 16 faces downward.

[0035] The battery cell 11 further includes a gas outflow valve 17. The gas outflow valve 17 is provided on the top surface 15. The gas outflow valve 17 is provided at the center of the top surface 15 in the X-axis direction. When the pressure inside the outer casing 12 becomes higher than a predetermined value, the gas outflow valve 17 allows the gas to flow out from the inside of the outer casing 12 through the top surface 15 to the outside of the outer casing 12 (a space 20 described later).

[0036] The battery cell 11 further includes a pair of electrode terminals 18, which are a positive terminal 18P and a negative terminal 18N. The electrode terminal 18 is provided on the top surface 15. The positive terminal 18P and the negative terminal 18N are provided to be separated from each other in the X-axis direction. The positive terminal 18P and the negative terminal 18N are provided on both sides of the gas outflow valve 17 in the X-axis direction.

[0037] The plurality of battery cells 11 are stacked in the following manner: between the battery cells 11, 11 adjacent in the Y-axis direction, the second side faces 13j face each other, and the second side faces 13k face each other. Thus, in the Y-axis direction of the stacked plurality of battery cells 11, the positive terminals 18P and the negative terminals 18N are arranged alternately. Between the battery cells 11, 11 adjacent in the Y-axis direction, the positive terminals 18P and the negative terminals 18N arranged in the Y-axis direction are connected to each other by a bus bar not shown. The plurality of battery cells 11 are electrically connected to each other in series.

[0038] like Figure 2As shown, a plurality of battery cells 11 stacked in the Y-axis direction constitute a single body stack 120. The single body stack 120 has a rectangular parallelepiped shape. The length of the single body stack 120 in the Y-axis direction is greater than the length of the single body stack 120 in the Z-axis direction, and greater than the length of the single body stack 120 in the X-axis direction. The plurality of battery cells 11 are arranged in a rectangular frame in which the Y-axis direction is the long side direction and the X-axis direction perpendicular to the Y-axis direction is the short side direction when viewed from above along the Z-axis direction, to constitute the single body stack 120. The rectangular frame mentioned here is the smallest imaginary frame line in which the plurality of battery cells 11 can be arranged.

[0039] The battery pack 100 also has a pair of end plates 91 and a pair of restraining rods 66 ( Figure 2 The diagram is omitted, see Figure 4 ). A pair of end plates 91 are respectively arranged at both ends of the monomer stack 120 (multiple battery cells 11) in the Y-axis direction. A pair of restraint rods 66 are arranged at both ends of the monomer stack 120 in the X-axis direction. The restraint rods 66 extend in the Y-axis direction and are connected to the pair of end plates 91 at both ends thereof. The multiple battery cells 11 are held together by the pair of end plates 91 and the pair of restraint rods 66.

[0040] The battery pack 100 further includes a shell body 31 and a cover 21. The shell body 31 and the cover 21 are made of metal. The shell body 31 and the cover 21 are formed of, for example, aluminum. The shell body 31 has an opening 30. The opening 30 opens upward. The cover 21 is mounted on the shell body 31 in a manner that closes the opening 30. The cover 21 and the shell body 31 together form a space 20 for accommodating a plurality of battery cells 11.

[0041] The housing body 31 has a bottom 51, a pair of first side portions 32, and a pair of second side portions 36. The bottom 51 has a wall shape in which the Z-axis direction is the thickness direction and is arranged along the X-axis-Y-axis plane. The bottom 51 has a rectangular shape when viewed from above along the Z-axis direction. The monomer stack 120 is placed on the bottom 51. A cooling plate 61 is inserted between the bottom 51 and the monomer stack 120. The cooling plate 61 is provided with a refrigerant passage 62 extending in the Y-axis direction.

[0042] A pair of first side portions 32 and a pair of second side portions 36 stand up from the periphery of the bottom portion 51. The pair of first side portions 32 face each other in the X-axis direction with the space 20 interposed therebetween. The first side portion 32 presents a wall shape in which the X-axis direction becomes the thickness direction and is arranged along the Y-axis-Z-axis plane. The pair of second side portions 36 face each other in the Y-axis direction with the space 20 interposed therebetween. The second side portion 36 presents a wall shape in which the Y-axis direction becomes the thickness direction and is arranged along the X-axis-Z-axis plane.

[0043] The bottom portion 51 is fastened to the pair of first side portions 32 and the pair of second side portions 36 by a plurality of bolts 52. The present invention is not limited to this configuration, and the bottom portion 51, the pair of first side portions 32, and the pair of second side portions 36 may be integrally formed of metal.

[0044] The space 20 is formed on the bottom 51 at a position surrounded by the pair of first side portions 32 and the pair of second side portions 36. The opening 30 is defined by the upper ends of the pair of first side portions 32 and the pair of second side portions 36. The space 20 is open to the space outside the housing body 31 through the opening 30.

[0045] The housing body 31 further includes a first flange portion 33. The first flange portion 33 extends in a flange shape in the surface direction of the X-axis-Y-axis plane from the upper ends of the pair of first side portions 32 and the pair of second side portions 36. The first flange portion 33 is provided in a frame shape along the upper ends of the pair of first side portions 32 and the pair of second side portions 36.

[0046] The cover 21 has a cover body 22 and a second flange 24. The cover body 22 constitutes the main part of the cover 21 and closes the opening 30. The cover body 22 has a tray shape with the Z-axis direction being the depth direction and opening downward. The second flange 24 extends in a flange shape from the lower end of the cover body 22 in the surface direction of the X-axis-Y-axis plane. The second flange 24 is arranged in a frame shape along the lower end of the cover body 22. The second flange 24 overlaps with the first flange 33 in the Z-axis direction. The first flange 33 and the second flange 24 are fastened to each other by a plurality of bolts 26, whereby the cover 21 is mounted on the housing body 31.

[0047] The battery pack 100 also has a plate member 41 and a gasket 46. The plate member 41 and the gasket 46 are formed of a material having a heat resistance to such an extent that they will not deform even when exposed to high-temperature gas or flames generated by the battery cell 11, and are preferably made of metal or ceramic. The plate member 41 and the gasket 46 are formed of, for example, a metal such as carbon steel, stainless steel, copper, aluminum or titanium, or a ceramic such as alumina, zirconia or silica. The plate member 41 and the gasket 46 may also be a member obtained by coating a resin material on the surface of these materials. The thickness of each of the plate member 41 and the gasket 46 is smaller than the thickness of the cover 21.

[0048] In the present embodiment, the plate member 41 and the gasket 46 are integrally formed of a metal or ceramic plate material. With such a configuration, the number of components of the battery pack 100 can be reduced, or the number of man-hours required to assemble the battery pack 100 can be reduced.

[0049] The plate member 41 is provided in the space 20. The plate member 41 is arranged between the plurality of battery cells 11 (cell assembly 120) and the cover 21 in the space 20. The top surface 15 of the battery cell 11 faces the plate member 41 in the Z-axis direction. The gasket 46 is clamped by the housing body 31 and the cover 21. The gasket 46 is inserted between the first flange portion 33 and the second flange portion 24. The gasket 46 receives the tightening force generated by the plurality of bolts 26 between the first flange portion 33 and the second flange portion 24.

[0050] The plate member 41 has an inclined portion 42. The inclined portion 42 faces the top surface 15 in the Z-axis direction. The inclined portion 42 faces the gas outflow valve 17 in the Z-axis direction. The inclined portion 42 faces the electrode terminal 18 (positive terminal 18P, negative terminal 18N) in the Z-axis direction. The inclined portion 42 is provided above the cell assembly 120 (battery cell 11).

[0051] The length of the inclined portion 42 in the X-axis direction is greater than the length of the cell assembly 120 (battery cell 11) in the X-axis direction. The length of the inclined portion 42 in the Y-axis direction is greater than the length of the cell assembly 120 in the Y-axis direction. The inclined portion 42 has a rectangular shape in which the Y-axis direction is the long side direction and the X-axis direction is the short side direction when viewed from above along the Z-axis direction. The range of the cell assembly 120 when viewed from above along the Z-axis direction is included in the range of the inclined portion 42 when viewed from above along the Z-axis direction.

[0052] In the X-axis-Z-axis plane Figure 4 In the cross section shown, the inclined portion 42 is inclined in such a manner that the distance L between the top surface 15 in the Z-axis direction and the inclined portion 42 becomes smaller as it approaches the end of the monomer aggregate 120 in the X-axis direction. The inclined portion 42 is inclined in such a manner that the distance L between the top surface 15 in the Z-axis direction and the inclined portion 42 becomes smaller as it approaches the two ends of the monomer aggregate 120 in the X-axis direction. The inclined portion 42 is inclined in such a manner that the distance L between the top surface 15 in the Z-axis direction and the inclined portion 42 is smaller at the end of the monomer aggregate 120 in the X-axis direction than at the center of the monomer aggregate 120 in the X-axis direction. The inclined portion 42 is inclined in such a manner that the distance L between the top surface 15 in the Z-axis direction and the inclined portion 42 becomes smaller as it goes from the center to the end of the monomer aggregate 120 in the X-axis direction. The inclined portion 42 is inclined with respect to each direction of the X-axis direction and the Z-axis direction.

[0053] The distance L between the top surface 15 and the inclined portion 42 in the Z-axis direction decreases as the distance in the X-axis direction from the gas outflow valve 17 decreases. The distance L between the top surface 15 and the inclined portion 42 in the Z-axis direction is maximum at a position on the virtual plane 110, and decreases as the distance in the X-axis direction from the virtual plane 110 decreases. The distance L between the top surface 15 and the inclined portion 42 in the Z-axis direction is constant regardless of the position in the Y-axis direction.

[0054] The battery pack 100 is cut along the X-axis-Z-axis plane. Figure 4 In the cross-sectional view in FIG. 4 , the inclined portion 42 has a curved cross-section. The inclined portion 42 may also have an arc-shaped cross-section formed with a certain curvature.

[0055] The plate member 41 further includes a base 44. The base 44 extends from the periphery of the inclined portion 42 toward the bottom 51 in the Z-axis direction. The base 44 and the inclined portion 42 form a tray shape with the Z-axis direction being the depth direction and open downward.

[0056] The gasket 46 is provided at the periphery of the base 44. The gasket 46 is provided along the periphery of the base 44 when viewed from above in the Z-axis direction. The gasket 46 extends in a convex shape from the lower end of the base 44 in the surface direction of the X-axis-Y-axis plane. The gasket 46 is provided in a frame shape along the lower end of the base 44.

[0057] The space 20 is divided into a space 20A and a space 20B by the plate member 41 and the gasket 46. The space 20B is surrounded by the plate member 41, the gasket 46 and the cover 21. The space 20A is surrounded by the plate member 41, the gasket 46 and the case body 31. A plurality of battery cells 11 are accommodated in the space 20A.

[0058] The battery pack 100 further includes a duct 70. The duct 70 is disposed opposite to the cell assembly 120 in the X-axis direction. The duct 70 is disposed opposite to the first side surface 14 of the battery cell 11. The duct 70 forms a gas flow passage 72. The gas flow passage 72 communicates with the space 20. The duct 70 discharges the gas flowing out of the gas outflow valve 17 from the space 20.

[0059] The housing body 31 further includes a rib 34. The rib 34 protrudes from the first side portion 32 in the X-axis direction and extends in a rib shape along the periphery of the first side portion 32. The duct 70 includes a pair of duct covers 71. The pair of duct covers 71 are respectively mounted on the pair of first side portions 32. The duct covers 71 are mounted on the first side portion 32 in a manner that abuts against the rib 34 in the X-axis direction.

[0060] The duct cover 71 forms a gas flow passage 72 together with the first side portion 32. A gas flow hole 35 is provided in the first side portion 32. The gas flow hole 35 is composed of a hole penetrating the first side portion 32, so that the space 20 (20A) and the gas flow passage 72 are connected. The gas flow passage 72 extends in the Y-axis direction and is open at one end thereof.

[0061] Assume the following situation: when a battery abnormality such as an internal short circuit of the battery cell 11 occurs, a flammable gas is generated inside the outer casing 12. The gas is discharged into the space 20 (20A) between the top surface 15 and the cover 21 through the gas outflow valve 17 ( Figure 4 The gas collides with the plate member 41, flows from the center of the space 20 (20A) in the X-axis direction to both ends, and then flows downward through the gap between the single layer stack 120 and the first side portion 32 ( Figure 4 The gas flows as indicated by arrows B and C in FIG. 1 ). The gas is discharged from the space 20 (20A) through the gas flow holes 35 to the gas flow passage 72 ( Figure 4 The gas flows in the Y-axis direction through the gas flow path 72 and is discharged to the outside of the pipe 70 ( Figure 1 Gas flow as shown by arrow E in FIG.

[0062] As the capacity of batteries has increased in recent years, the amount of gas generated in the battery cells 11 has increased. As a result, high-pressure gas may be ejected from the battery cells 11, or the gas may become hot due to the increased pressure of the gas, or spontaneous combustion may occur. In response to such situations, the battery pack 100 of this embodiment is provided with a plate member 41 and a gasket 46.

[0063] First, the gasket 46 made of metal or ceramics sandwiched between the housing body 31 and the cover 21 can prevent gas from leaking from a portion other than the above-mentioned exhaust gas path.

[0064] Secondly, by using the plate member 41 disposed between the plurality of battery cells 11 (cell assembly 120) and the cover 21 in the space 20, the high-pressure gas ejected from the battery cells 11 or the shock wave accompanying the natural fire is blocked, thereby preventing the cover 21 from being damaged. In addition, the plate member 41 also has a heat shielding function to prevent the cover 21 from being exposed to high-temperature gas. In such a case, the gas blocked by the plate member 41 is guided toward the two ends of the cell assembly 120 in the X-axis direction (in the direction away from the gas outflow valve 17) by the inclined portion 42. Since the length of the cell assembly 120 in the X-axis direction is smaller than the length of the cell assembly 120 in the Y-axis direction, the gas can be quickly evacuated from between the top surface 15 and the cover 21 and discharged from the space 20 through the duct 70. In this way, the cover 21 can be more reliably prevented from being damaged.

[0065] Figures 5 to 7 It is shown Figure 4 A cross-sectional view of a modified example of the battery pack in FIG. Figure 5 In this modification, in the cross-sectional view of the battery pack 100 cut along the X-axis-Z-axis plane, the inclined portion 42 has a straight cross-section. The inclined portion 42 has a certain inclination in the X-axis-Z-axis plane and extends straight between the imaginary plane 110 and the base 44.

[0066] Reference Figure 6 In this modification, in the cross-sectional view of the battery pack 100 cut along the X-axis-Z-axis plane, the inclined portion 42 has a straight-line cross-section. The inclined portion 42 has a first portion 42g and a second portion 42h. The first portion 42g extends between the imaginary plane 110 and the second portion 42h while having a certain inclination in the X-axis-Z-axis plane. The second portion 42h extends between the first portion 42g and the base 44 while having a certain inclination different from that of the first portion 42g in the X-axis-Z-axis plane.

[0067] Reference Figure 7 In this modification, the plate member 41 and the gasket 46 are provided separately. The plate member 41 is attached to the housing body 31 .

[0068] As shown in the above modified example, the shape of the inclined portion 42 is not particularly limited as long as the distance L between the top surface 15 in the Z-axis direction and the inclined portion 42 decreases as the distance in the X-axis direction away from the gas outflow valve 17 decreases. In addition, the support structure of the plate member 41 in the space 20 is not particularly limited. As an example other than the above structure, the plate member 41 may be supported by the end plate 91 or the cover 21.

[0069] In order to reinforce the plate member 41, a rib or a concave-convex part may be provided on the inclined part 42. In addition, the inclined part 42 may also have a shape inclined so that the distance between the top surface 15 in the Z-axis direction and the inclined part 42 decreases as it approaches the end of the monomer assembly 120 in the Y-axis direction in the cross section cut along the Y-axis-Z-axis plane. In this case, the inclined part 42 has a dome shape.

[0070] To summarize the structure of the battery pack 100 according to the embodiment of the present invention described above, the battery pack 100 according to the present embodiment includes: a plurality of battery cells 11; a housing body 31 having an opening 30; a cover 21 attached to the housing body 31 in a manner to close the opening 30 and forming a space 20 for accommodating the plurality of battery cells 11 together with the housing body 31; a metal or ceramic plate member 41 disposed between the plurality of battery cells 11 and the cover 21 in the space 20; and a metal or ceramic gasket 46 sandwiched between the housing body 31 and the cover 21. The battery cell 11 includes: an outer casing 12 including a top surface 15 facing the plate member 41 and accommodating an electrode body and an electrolyte; and a gas outflow valve 17 for allowing gas to flow out from the inside of the outer casing 12 through the top surface 15 to the space 20 when the pressure inside the outer casing 12 becomes equal to or higher than a predetermined value. A plurality of battery cells 11 are arranged in a frame to constitute a cell assembly 120. The frame is a rectangular shape in which the Y-axis direction as the second direction is the long side direction and the X-axis direction as the third direction orthogonal to the Y-axis direction is the short side direction when viewed along the Z-axis direction as the first direction orthogonal to the top surface 15. The plate member 41 has an inclined portion 42. The inclined portion 42 is inclined so that the distance L between the top surface 15 in the Z-axis direction and the inclined portion 42 becomes smaller as it approaches the end of the cell assembly 120 in the X-axis direction.

[0071] According to the battery pack 100 of the first embodiment of the present invention thus constructed, even when high-pressure gas is ejected from the battery cells 11 or spontaneous combustion occurs due to the ejection of high-pressure gas, leakage of gas from the space 20 and damage to the cover 21 can be more reliably prevented.

[0072] (Implementation Method 2)

[0073] Figure 8 This is a cross-sectional view showing a battery pack according to Embodiment 2 of the present invention. Figure 8 Implementation 1 Figure 4 correspond. Fig. 9 It shows the composition Figure 8 A top view of the battery pack's monomer assembly.

[0074] The battery pack of this embodiment has basically the same structure as the battery pack 100 of Embodiment 1. Hereinafter, the overlapping structures will not be described repeatedly.

[0075] Reference Figure 8 as well as Fig. 9In this embodiment, the battery cells 11 are stacked in two rows in the Y-axis direction. The plurality of battery cells 11 are arranged in a rectangular frame 130 in which the Y-axis direction is the long side direction and the X-axis direction is the short side direction when viewed along the Z-axis direction, forming a cell assembly 120. The frame 130 is the smallest imaginary frame line in which the plurality of battery cells 11 are arranged. The short side of the frame 130 extends in the X-axis direction, and the long side of the frame 130 extends in the Y-axis direction.

[0076] The cell assembly 120 is composed of a first cell assembly 120A and a second cell assembly 120B. The first cell assembly 120A is composed of a plurality of battery cells 11 stacked in a row in the Y-axis direction. The second cell assembly 120B is composed of a plurality of battery cells 11 stacked in a row in the Y-axis direction. The first cell assembly 120A and the second cell assembly 120B are arranged at intervals from each other in the X-axis direction.

[0077] Fig.10 It is shown Figure 8 A cross-sectional view of a modified example of the battery pack. Fig.11 It is composed Fig.10 A top view of the battery pack's monomer assembly.

[0078] Reference Fig.10 as well as Fig.11 In this modification, the battery cell 11 is cylindrical. The plurality of battery cells 11 are arranged in an upright position with the cylinder axis of each battery cell 11 extending in the Z-axis direction, spaced apart from each other in the X-axis-Y-axis plane. The gas outflow valve 17 is provided on the top surface 15 of the battery cell 11. The gas outflow valve 17 may also be provided on the inner side of the sealing body constituting the top surface 15 of the battery cell 11.

[0079] The plurality of battery cells 11 are arranged in a rectangular frame 130 with the Y-axis direction being the long side direction and the X-axis direction being the short side direction when viewed in the Z-axis direction, and constitute a cell assembly 120 .

[0080] exist Figures 8 to 11 In the illustrated configuration, the inclined portion 42 is inclined such that the distance L between the top surface 15 in the Z-axis direction and the inclined portion 42 decreases as it approaches the end of the cell assembly 120 in the X-axis direction. In this embodiment, the plurality of battery cells 11 may include a battery cell 11 whose topmost portion of the inclined portion 42 is not located directly above the gas outflow valve 17.

[0081] According to the battery pack according to the second embodiment of the present invention configured in this manner, the same effects as those of the battery pack 100 according to the first embodiment can be achieved.

[0082] Although the embodiments of the present invention have been described, the embodiments disclosed this time should be considered to be illustrative in all aspects and not restrictive. The scope of the present invention is indicated by the claims, and it is intended to include all modifications within the meaning and scope equivalent to the claims.

Claims

1. A battery pack, wherein: The battery pack has: Multiple battery cells; a housing body having an opening; a cover, the cover being mounted on the housing body in a manner of closing the opening, and forming a space for accommodating the plurality of battery cells together with the housing body; a plate member made of metal or ceramic, arranged between the plurality of battery cells and the cover in the space; and a gasket, which is made of metal or ceramic and is held by the housing body and the cover; The battery cell has: an outer casing including a top surface facing the plate member and accommodating the electrode body and the electrolyte; and a gas outflow valve that allows gas to flow out of the space from the interior of the outer casing through the top surface when the pressure inside the outer casing becomes greater than a predetermined value, The plurality of battery cells are arranged in a frame to form a cell assembly, and the frame is a rectangular shape in which a second direction is a long side direction and a third direction orthogonal to the second direction is a short side direction when viewed along a first direction orthogonal to the top surface. The plate member has an inclined portion, and the inclined portion is inclined so that a distance between the top surface in the first direction and the inclined portion decreases as it approaches an end portion of the unit cell assembly in the third direction.

2. The battery pack according to claim 1, wherein: The above battery cells are square. The plurality of battery cells are stacked in a row in the second direction. A distance between the top surface and the inclined portion in the first direction decreases as the distance from the gas outflow valve increases in the third direction.

3. The battery pack according to claim 1 or 2, wherein: The battery pack further includes a duct that is provided facing the cell assembly in the third direction and forms a gas flow path that communicates with the space and discharges the gas from the space.

4. The battery pack according to claim 1 or 2, wherein: The plate member and the gasket are integrally formed from a metal or ceramic plate material.

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