Battery pack

Abstract

To provide a battery pack capable of more securely preventing leakage of gas and damage of a cover.SOLUTION: A battery pack includes: a plurality of battery cells 11; a case body 31; a cover 21 that is attached to the case body 31 and that forms, together with the case body 31, a space 20 for accommodating the plurality of battery cells 11; a plate member 41 disposed between each of the plurality of battery cells 11 and the cover 21 in the space 20; and a gasket 46 sandwiched by the case body 31 and the cover 21. The plurality of battery cells 11 are disposed in a frame to form a cell assembly 120, the frame having a rectangular shape in which a Y-axis direction corresponds to a long-side direction and an X-axis direction orthogonal to the Y-axis direction corresponds to a short-side direction. The plate member 41 has an inclined portion 42, and the inclined portion 42 is inclined such that a distance L between a top surface 15 and the inclined portion 42 in the Z-axis direction is decreased in a direction toward an end portion of the cell assembly 120 in the X-axis direction.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] For example, International Publication No. 2020 / 189590 (Patent Document 1) discloses a battery pack comprising a secondary battery, a housing for accommodating the secondary battery, and a plate-shaped reinforcing portion extending from one end of the housing in the longitudinal direction to the other end and arranged in the height direction of the secondary battery to reinforce the housing.

[0003] In addition, JP 2021-535556 A (Patent Document 2) discloses a battery pack comprising a single cell, a first panel and a second panel connected to the upper and lower surfaces of the single cell, respectively, and a heat conduction plate provided between the single cell and the first panel. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2020 / 189590 [Patent Document 2] Special Publication No. 2021-535556 Summary of the Invention [Problem to be solved by the invention]

[0005] In the battery pack disclosed in the aforementioned Patent Document 1, the housing (case) that houses the secondary battery is composed of a rectangular box-shaped main body with an open top and a cover that covers the opening of the main body. In such a battery pack, if high-pressure gas is released from the battery cell in the event of a battery abnormality, there is a concern that the gas may leak between the main body and the cover. There is also a concern that the gas released from the battery cell may hit the cover and damage it.

[0006] SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a battery pack that can more reliably prevent gas leakage and damage to the cover. [Means for solving the problem]

[0007] [1] A battery pack comprising: a plurality of battery cells; a case body having an opening; a cover attached to the case body so as to close the opening and forming, together with the case body, a space for accommodating the plurality of battery cells; a metal or ceramic plate member disposed between the plurality of battery cells and the cover in the space; and a metal or ceramic gasket sandwiched between the case body and the cover, wherein the battery cells include a top surface facing the plate member, an exterior body accommodating an electrode assembly and an electrolyte; and a battery pack inside the exterior body. a gas outflow valve that allows gas to flow from inside the exterior body into the space through the top surface when the pressure reaches or exceeds a predetermined value, the plurality of battery cells are arranged within a rectangular frame in which, when viewed in a first direction perpendicular to the top surface, a second direction is the longitudinal direction and a third direction perpendicular to the second direction is the lateral direction, thereby forming a cell assembly, and the plate member has an inclined portion that is inclined so that the distance between the top surface and the inclined portion in the first direction becomes smaller as the distance approaches the end of the cell assembly in the third direction.

[0008] In a battery pack configured in this manner, the metal or ceramic gasket can more reliably prevent gas leakage from between the case body and the cover. Furthermore, the metal or ceramic plate member can capture gas generated from the battery cells, preventing damage to the cover. In this case, the inclined portion guides the gas captured by the plate member toward the end of the cell assembly in the third direction. Because the length of the cell assembly in the third direction is shorter than the length of the cell assembly in the second direction, gas can be quickly evacuated from between the top surface and the cover, more reliably preventing damage to the cover.

[0009] [2] The battery pack described in [1], wherein the battery cells are rectangular, and multiple battery cells are stacked in a row in the second direction, and the 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.

[0010] In a battery pack configured in this manner, the inclined portion allows the gas received by the plate member from the gas outlet valve to be more efficiently guided toward the end of the cell assembly in the third direction.

[0011] [3] The battery pack according to [1] or [2], further comprising a duct that is disposed opposite the cell assembly in the third direction, forms a gas flow passage that communicates with the space, and exhausts the gas from the space.

[0012] In a battery pack configured in this manner, the gas evacuated from between the top surface and the cover is discharged from the space through the duct, thereby more reliably preventing damage to the cover.

[0013] [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.

[0014] A battery pack configured in this manner can prevent gas leakage and damage to the cover while simplifying the configuration of the battery pack. [Effects of the Invention]

[0015] As described above, according to the present invention, it is possible to provide a battery pack that can more reliably prevent gas leakage and damage to the cover. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a perspective view showing a battery pack in accordance with a first embodiment of the present invention. [Figure 2] FIG. 2 is an exploded view showing the battery pack in FIG. [Figure 3] FIG. 2 is a perspective view showing a battery cell. [Figure 4] 4 is a cross-sectional view schematically showing the battery pack as seen in the direction of the arrows on line IV-IV in FIG. 1. FIG. [Figure 5] FIG. 5 is a cross-sectional view showing a first modified example of the battery pack in FIG. [Figure 6] 5 is a cross-sectional view showing a second modified example of the battery pack in FIG. [Figure 7] 5 is a cross-sectional view showing a third modified example of the battery pack in FIG. 4. FIG. [Figure 8] FIG. 10 is a cross-sectional view showing a battery pack in accordance with a second embodiment of the present invention. [Figure 9] 9 is a top view showing a cell assembly that constitutes the battery pack in FIG. 8. FIG. [Figure 10] 9 is a cross-sectional view showing a modified example of the battery pack in FIG. 8. FIG. [Figure 11] 11 is a top view showing a cell assembly that constitutes the battery pack in FIG. 10. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to the accompanying drawings, in which the same or equivalent components are designated by the same reference numerals.

[0018] (Embodiment 1) Fig. 1 is a perspective view showing a battery pack in embodiment 1 of the present invention. Fig. 2 is an exploded view showing the battery pack in Fig. 1. Fig. 3 is a perspective view showing a battery cell. Fig. 4 is a cross-sectional view schematically showing the battery pack as seen in the direction of the arrows on line IV-IV in Fig. 1.

[0019] 1 to 4, a battery pack 100 is used as a power source for driving a vehicle such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or a battery electric vehicle (BEV).

[0020] In this specification, for convenience in explaining the structure of the battery pack 100, the axis extending in the stacking direction of a plurality of battery cells 11 (described later) and in the horizontal direction is referred to as the "Y axis," the axis perpendicular to the Y axis and extending in the horizontal direction is referred to as the "X axis," and the axis extending in the vertical direction is referred to as the "Z axis." As shown in Fig. 4, the battery pack 100 basically has a structure that is symmetrical with respect to an imaginary plane 110 that is parallel to the Y-axis-Z axis plane.

[0021] 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 made of lithium ion batteries. The battery cells 11 are rectangular and have the shape of a thin rectangular parallelepiped plate. The plurality of battery cells 11 are stacked so that the Y-axis direction is the thickness direction of the battery cells 11.

[0022] The battery cell 11 has an exterior body 12. The exterior body 12 is made of a rectangular parallelepiped housing and forms the exterior of the battery cell 11. The exterior body 12 contains an electrode assembly and an electrolyte.

[0023] The exterior body 12 has a pair of first side surfaces 14 (14j, 14k), a pair of second side surfaces 13 (13j, 13k), a top surface 15, and a bottom surface 16.

[0024] The first side surface 14 is a plane perpendicular 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 each other in the X-axis direction. The second side surface 13 is a plane perpendicular to the Y-axis. The second side surface 13 has the largest area of ​​the multiple side surfaces of the exterior body 12. The second side surface 13j and the second side surface 13k face opposite each other in the Y-axis direction. The top surface 15 and the bottom surface 16 each form a plane perpendicular to the Z-axis. The top surface 15 faces upward. The bottom surface 16 faces downward.

[0025] The battery cell 11 further has 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 position of the top surface 15 in the X-axis direction. When the pressure inside the exterior body 12 reaches or exceeds a predetermined value, the gas outflow valve 17 allows gas to flow from inside the exterior body 12 through the top surface 15 to the outside of the exterior body 12 (space 20, described below).

[0026] The battery cell 11 further has electrode terminals 18, each of which is a pair of a positive terminal 18P and a negative terminal 18N. The electrode terminals 18 are provided on the top surface 15. The positive terminal 18P and the negative terminal 18N are provided spaced apart from each other in the X-axis direction. The positive terminal 18P and the negative terminal 18N are provided on either side of the gas outflow valve 17 in the X-axis direction.

[0027] The multiple battery cells 11 are stacked such that the second side surfaces 13j face each other and the second side surfaces 13k face each other between adjacent battery cells 11 in the Y-axis direction. As a result, the positive electrode terminals 18P and the negative electrode terminals 18N are arranged alternately in the Y-axis direction in which the multiple battery cells 11 are stacked. Between adjacent battery cells 11 in the Y-axis direction, the positive electrode terminals 18P and the negative electrode terminals 18N arranged in the Y-axis direction are connected to each other by a bus bar (not shown). The multiple battery cells 11 are electrically connected to each other in series.

[0028] As shown in FIG. 2, a cell assembly 120 is formed by a plurality of battery cells 11 stacked in the Y-axis direction. The cell assembly 120 has a rectangular parallelepiped shape. The length of the cell assembly 120 in the Y-axis direction is greater than the length of the cell assembly 120 in the Z-axis direction and is greater than the length of the cell assembly 120 in the X-axis direction. In a plan view seen in the Z-axis direction, the plurality of battery cells 11 are arranged within a rectangular frame whose longitudinal direction is the Y-axis direction and whose lateral direction is the X-axis direction, which is orthogonal to the Y-axis direction, to form the cell assembly 120. The rectangular frame here is the smallest imaginary frame within which the plurality of battery cells 11 can be arranged.

[0029] The battery pack 100 further includes a pair of end plates 91 and a pair of bind bars 66 (not shown in FIG. 2 , see FIG. 4 ). The pair of end plates 91 are respectively arranged at both ends of the cell assembly 120 (plurality of battery cells 11) in the Y-axis direction. The pair of bind bars 66 are respectively arranged at both ends of the cell assembly 120 in the X-axis direction. The bind bars 66 extend in the Y-axis direction and are connected at both ends to the pair of end plates 91. The plurality of battery cells 11 are held together by the pair of end plates 91 and the pair of bind bars 66.

[0030] The battery pack 100 further includes a case body 31 and a cover 21. The case body 31 and the cover 21 are made of metal. The case body 31 and the cover 21 are formed of aluminum, for example. The case body 31 has an opening 30. The opening 30 faces upward. The cover 21 is attached to the case body 31 so as to close the opening 30. The cover 21, together with the case body 31, forms a space 20 that houses multiple battery cells 11.

[0031] The case 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 arranged along the X-axis-Y-axis plane, with the thickness direction being in the Z-axis direction. The bottom 51 has a rectangular shape in a plan view seen in the Z-axis direction. The cell assembly 120 is placed on the bottom 51. A cooling plate 61 is interposed between the bottom 51 and the cell assembly 120. The cooling plate 61 is provided with a refrigerant passage 62 extending in the Y-axis direction.

[0032] The pair of first side portions 32 and the pair of second side portions 36 rise 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 in between. The first side portions 32 have a wall shape with the X-axis direction being the thickness direction and arranged along the Y-axis-axis plane. The pair of second side portions 36 face each other in the Y-axis direction, with the space 20 in between. The second side portions 36 have a wall shape with the Y-axis direction being the thickness direction and arranged along the X-axis-axis plane.

[0033] The bottom portion 51 is fastened to the pair of first side portions 32 and the pair of second side portions 36 using a plurality of bolts 52. This configuration is not limited thereto, and the bottom portion 51, the pair of first side portions 32, and the pair of second side portions 36 may be integrally molded from metal.

[0034] 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 case body 31 through the opening 30.

[0035] The case body 31 further has a first flange 33. The first flange 33 extends in a flange-like 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 33 is provided in a frame-like shape along the upper ends of the pair of first side portions 32 and the pair of second side portions 36.

[0036] The cover 21 has a cover main body 22 and a second flange 24. The cover main body 22 forms the main portion of the cover 21 and closes the opening 30. The cover main body 22 has a saucer shape that opens downward, with the Z-axis direction being the depth direction. The second flange 24 extends in a flange-like manner from the lower end of the cover main body 22 in the surface direction of the X-axis-Y-axis plane. The second flange 24 is provided in a frame-like shape along the lower end of the cover main 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 using a plurality of bolts 26, thereby attaching the cover 21 to the case main body 31.

[0037] The battery pack 100 further includes a plate member 41 and a gasket 46. The plate member 41 and the gasket 46 are made of a heat-resistant material that will not deform even when exposed to high-temperature gas or flames generated by the battery cells 11, and are preferably made of metal or ceramic. The plate member 41 and the gasket 46 are made 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 surfaces of the plate member 41 and the gasket 46 may be coated with a resin material. The thickness of the plate member 41 and the gasket 46 is smaller than the thickness of the cover 21.

[0038] In the present embodiment, plate member 41 and gasket 46 are integrally formed from a metal or ceramic plate material. This configuration can reduce the number of parts in battery pack 100 and the number of steps required to assemble battery pack 100.

[0039] The plate member 41 is provided in the space 20. The plate member 41 is arranged in the space 20 between the multiple battery cells 11 (cell assembly 120) and the cover 21. The top surfaces 15 of the battery cells 11 face the plate member 41 in the Z-axis direction. The gasket 46 is sandwiched between the case body 31 and the cover 21. The gasket 46 is interposed between the first flange 33 and the second flange 24. The gasket 46 receives the fastening force of the multiple bolts 26 between the first flange 33 and the second flange 24.

[0040] 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 terminals 18 (positive electrode terminal 18P, negative electrode terminal 18N) in the Z-axis direction. The inclined portion 42 is provided above the cell assembly 120 (battery cells 11).

[0041] 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. In a plan view in the Z-axis direction, the inclined portion 42 has a rectangular shape with the Y-axis direction as the longitudinal direction and the X-axis direction as the lateral direction. The range of the cell assembly 120 in a plan view in the Z-axis direction is included in the range of the inclined portion 42 in a plan view in the Z-axis direction.

[0042] In the cross section shown in FIG. 4 taken along the X-axis-Z-axis plane, the inclined portion 42 is inclined such that the distance L between the top surface 15 and the inclined portion 42 in the Z-axis direction decreases toward the ends of the cell assembly 120 in the X-axis direction. The inclined portion 42 is inclined such that the distance L between the top surface 15 and the inclined portion 42 in the Z-axis direction decreases toward both ends of the cell assembly 120 in the X-axis direction. The inclined portion 42 is inclined such that the distance L between the top surface 15 and the inclined portion 42 in the Z-axis direction is smaller at the ends of the cell assembly 120 in the X-axis direction than at the center of the cell assembly 120 in the X-axis direction. The inclined portion 42 is inclined such that the distance L between the top surface 15 and the inclined portion 42 in the Z-axis direction decreases from the center to the ends of the cell assembly 120 in the X-axis direction. The inclined portion 42 is inclined in both the X-axis and Z-axis directions.

[0043] Distance L between top surface 15 and inclined portion 42 in the Z-axis direction decreases with increasing distance from gas outflow valve 17 in the X-axis direction. Distance L between top surface 15 and inclined portion 42 in the Z-axis direction is maximum at a position on imaginary plane 110 and decreases with increasing distance from imaginary plane 110 in the X-axis direction. Distance L between top surface 15 and inclined portion 42 in the Z-axis direction is constant regardless of the position in the Y-axis direction.

[0044] 4, in which the battery pack 100 is cut along the X-axis-Z-axis plane, the inclined portion 42 has a curved cross section. The inclined portion 42 may have an arc-shaped cross section with a constant curvature.

[0045] The plate member 41 further has a base 44. The base 44 extends from the periphery of the inclined portion 42 in the Z-axis direction toward the bottom 51. The base 44, together with the inclined portion 42, has a depth direction in the Z-axis direction and is saucer-shaped with an opening facing downward.

[0046] The gasket 46 is provided on the periphery of the base 44. The gasket 46 is provided along the periphery of the base 44 in a plan view seen in the Z-axis direction. The gasket 46 spreads out in a flange-like 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-like shape along the lower end of the base 44.

[0047] Space 20 is divided into space 20A and space 20B by plate member 41 and gasket 46. Space 20B is surrounded by plate member 41, gasket 46, and cover 21. Space 20A is surrounded by plate member 41, gasket 46, and case body 31. Multiple battery cells 11 are housed in space 20A.

[0048] The battery pack 100 further includes a duct 70. The duct 70 is provided opposite the cell assembly 120 in the X-axis direction. The duct 70 is provided opposite 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 exhausts the gas that has flowed out from the gas outflow valve 17 from the space 20.

[0049] The case body 31 further has a rib portion 34. The rib portion 34 protrudes from the first side portion 32 in the X-axis direction and extends in a rib-like manner along the periphery of the first side portion 32. The duct 70 has a pair of duct covers 71. The pair of duct covers 71 are attached to the pair of first side portions 32, respectively. The duct covers 71 are attached to the first side portions 32 so as to abut against the rib portion 34 in the X-axis direction.

[0050] Duct cover 71, together with first side portion 32, forms gas flow passage 72. Gas flow hole 35 is provided in first side portion 32. Gas flow hole 35 is a hole that penetrates first side portion 32, and connects space 20 (20A) and gas flow passage 72. Gas flow passage 72 extends in the Y-axis direction and is open at one end thereof.

[0051] It is assumed that in the event of a battery abnormality such as an internal short circuit in the battery cell 11, flammable gas may be generated inside the exterior body 12. The gas may escape through the gas outlet valve 17 to the top surface 15 and the cover. 21 The gas collides with the plate member 41, flows from the center of the space 20 (20A) in the X-axis direction toward both ends, and then flows downward through the gap between the cell assembly 120 and the first side portion 32 (gas flow indicated by arrows B and C in FIG. 4). The gas is discharged from the space 20 (20A) through the gas flow holes 35 to the gas flow passage 72 (gas flow indicated by arrow D in FIG. 4). The gas flows through the gas flow passage 72 in the Y-axis direction and is discharged to the outside of the duct 70 (gas flow indicated by arrow E in FIG. 1).

[0052] As batteries have become higher in capacity in recent years, the amount of gas generated in battery cells 11 has increased. This can cause high-pressure gas to be ejected from battery cells 11, or the increased gas pressure can cause the gas to heat up and spontaneously ignite. To prepare for such situations, battery pack 100 in this embodiment is provided with plate member 41 and gasket 46.

[0053] First, the metal or ceramic gasket 46 sandwiched between the case body 31 and the cover 21 can prevent gas from leaking from any location other than the above-mentioned exhaust gas path.

[0054] Next, in the space 20, the plate member 41 disposed between the multiple battery cells 11 (cell assembly 120) and the cover 21 can absorb high-pressure gas ejected from the battery cells 11 or shock waves caused by spontaneous combustion, thereby preventing damage to the cover 21. In addition, the plate member 41 also has a heat-shielding function that prevents the cover 21 from being exposed to high-temperature gas. In such cases, the inclined portions 42 guide the gas received by the plate member 41 toward both ends of the cell assembly 120 in the X-axis direction (away from the gas outlet valve 17). Because the length of the cell assembly 120 in the X-axis direction is shorter 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. This more reliably prevents damage to the cover 21.

[0055] 5 to 7 are cross-sectional views showing modified examples of the battery pack in Fig. 4. Referring to Fig. 5, in this modified example, in a cross-sectional view of battery pack 100 cut along the X-axis-Z-axis plane, inclined portion 42 has a linear cross section. Inclined portion 42 extends linearly between imaginary plane 110 and base portion 44 while having a certain inclination in the X-axis-Z-axis plane.

[0056] 6, in this modification, in a cross-sectional view of battery pack 100 taken along the X-Z plane, inclined portion 42 has a linear cross section. Inclined portion 42 has a first portion 42g and a second portion 42h. First portion 42g extends between imaginary plane 110 and second portion 42h at a constant inclination in the X-Z plane. Second portion 42h extends between first portion 42g and base 44 at a constant inclination different from that of first portion 42g in the X-Z plane.

[0057] 7, in this modification, a plate member 41 and a gasket 46 are provided as separate bodies. The plate member 41 is attached to the case body 31.

[0058] As exemplified in the above-described modified examples, the shape of the inclined portion 42 is not particularly limited as long as the distance L between the top surface 15 and the inclined portion 42 in the Z-axis direction decreases with increasing distance from the gas outflow valve 17 in the X-axis direction. Furthermore, the support structure of the plate member 41 in the space 20 is not particularly limited. As an example other than the above, the plate member 41 may be supported by the end plate 91 or the cover 21.

[0059] Furthermore, ribs or irregularities may be provided on the inclined portion 42 to reinforce the plate member 41. Furthermore, the inclined portion 42 may have a shape that is inclined so that the distance between the top surface 15 and the inclined portion 42 in the Z-axis direction becomes smaller as the distance approaches the end of the cell assembly 120 in the Y-axis direction, even in a cross section cut along the Y-axis-Z-axis plane. In this case, the inclined portion 42 has a dome shape.

[0060] 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 embodiment includes a plurality of battery cells 11, a case body 31 having an opening 30, a cover 21 attached to the case body 31 so as to close the opening 30 and which, together with the case body 31, forms a space 20 for accommodating the plurality of battery cells 11, 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 case body 31 and the cover 21. The battery cell 11 includes an exterior body 12 including a top surface 15 facing the plate member 41 and accommodating an electrode assembly and an electrolyte, and a gas outflow valve 17 which allows gas to flow from inside the exterior body 12 to the space 20 through the top surface 15 when the pressure inside the exterior body 12 reaches or exceeds a predetermined value. When viewed in the Z-axis direction (first direction orthogonal to the top surface 15), the multiple battery cells 11 are arranged within a rectangular frame whose longitudinal direction is the Y-axis direction (second direction) and whose lateral direction is the X-axis direction (third direction orthogonal to the Y-axis direction), thereby forming a cell assembly 120. 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 and the inclined portion 42 in the Z-axis direction becomes smaller as the distance approaches the end of the cell assembly 120 in the X-axis direction.

[0061] With the battery pack 100 of the first embodiment of the present invention configured in this manner, even if high-pressure gas is ejected from the battery cell 11 or spontaneous combustion occurs as a result of the ejection of high-pressure gas, it is possible to more reliably prevent gas leakage from the space 20 and damage to the cover 21.

[0062] (Embodiment 2) Fig. 8 is a cross-sectional view showing a battery pack in accordance with embodiment 2 of the present invention. Fig. 8 corresponds to Fig. 4 in embodiment 1. Fig. 9 is a top view showing a cell assembly constituting the battery pack in Fig. 8.

[0063] The battery pack of the present embodiment has basically the same structure as battery pack 100 of Embodiment 1. Hereinafter, description of the overlapping structure will not be repeated.

[0064] 8 and 9, in this embodiment, battery cells 11 are stacked in two rows in the Y-axis direction. When viewed in the Z-axis direction, the multiple battery cells 11 are arranged within a rectangular frame 130 whose longitudinal direction is the Y-axis direction and whose lateral direction is the X-axis direction, thereby constituting a cell assembly 120. The frame 130 is the smallest imaginary frame within which the multiple 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.

[0065] 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.

[0066] Fig. 10 is a cross-sectional view showing a modification of the battery pack in Fig. 8. Fig. 11 is a top view showing a cell assembly that constitutes the battery pack in Fig. 10.

[0067] 10 and 11, in this modification, the battery cells 11 are cylindrical. The battery cells 11 are arranged in an upright position with the cylindrical axis of each battery cell 11 extending in the Z-axis direction and spaced apart from one another 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 be provided inside a sealing body that forms the top surface 15 of the battery cell 11.

[0068] The multiple battery cells 11 are arranged in a rectangular frame 130, with the Y axis direction being the longitudinal direction and the X axis direction being the lateral direction when viewed in the Z axis direction, to form a cell assembly 120.

[0069] 8 to 11, the inclined portion 42 is inclined so that the distance L between the top surface 15 and the inclined portion 42 in the Z-axis direction becomes smaller as the distance approaches the end of the cell assembly 120 in the X-axis direction. In this embodiment, the multiple battery cells 11 may include a battery cell 11 in which the top of the inclined portion 42 is not located directly above the gas outflow valve 17.

[0070] The battery pack according to the second embodiment of the present invention configured in this manner can achieve the same effects as battery pack 100 according to the first embodiment.

[0071] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0072] 11 battery cell, 12 exterior body, 13, 13j, 13k second side, 14, 14j, 14k first side, 15 top surface, 16 bottom surface, 17 gas outflow valve, 18 electrode terminal, 18N negative electrode terminal, 18P positive electrode terminal, 20, 20A, 20B space, 21 cover, 22 cover main body, 24 second flange portion, 26, 52 bolt, 30 opening, 31 case main body, 32 first side portion, 33 first flange portion, 34 rib portion, 35 gas circulation hole, 36 second side portion, 41 plate member, 42 inclined portion, 42g first portion, 42h second portion, 44 base, 46 gasket, 51 bottom portion, 61 cooling plate, 62 refrigerant passage, 66 bind bar, 70 duct, 71 Duct cover, 72 gas flow passage, 91 end plate, 100 battery pack, 110 virtual plane, 120 cell assembly, 120A first cell assembly, 120B second cell assembly, 130 frame.

Claims

1. A plurality of battery cells; a case body having an opening; a cover attached to the case body so as to close the opening, and forming, together with the case body, a space for accommodating the plurality of battery cells; a metal or ceramic plate member disposed between the plurality of battery cells and the cover in the space; a metal or ceramic gasket sandwiched between the case body and the cover, The battery cell is an exterior body including a top surface facing the plate member and accommodating an electrode assembly and an electrolyte; a gas outflow valve that allows gas to flow from inside the exterior body to the space through the top surface when the pressure inside the exterior body reaches or exceeds a predetermined value, the plurality of battery cells are arranged within a rectangular frame, when viewed in a first direction orthogonal to the top surface, in which a second direction is a longitudinal direction and a third direction orthogonal to the second direction is a lateral direction, to form a cell assembly; the plate member has an inclined portion, and the inclined portion is inclined such that a distance between the top surface and the inclined portion in the first direction becomes smaller as the plate member approaches an end of the cell assembly in the third direction; a gas passage through which gas that has been released into the space through the top surface by the gas outflow valve flows after colliding with the plate member is provided between the cell assembly and the case body in the third direction.

2. the battery cells are rectangular; the plurality of battery cells are stacked in a row in the second direction, The battery pack according to claim 1 , wherein the distance between the top surface and the inclined portion in the first direction decreases with increasing distance from the gas outflow valve in the third direction.

3. 3 . The battery pack according to claim 1 , further comprising a duct that is provided opposite the cell assembly in the third direction, that forms a gas flow passage that communicates with the space, and that exhausts the gas from the space.

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

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