Battery pack

Abstract

A battery pack is provided with: a plurality of battery cells; a case main body having an opening portion; a cover attached to the case main body so as to close the opening, the cover forming, together with the case main body, a space in which the plurality of battery cells are accommodated; and a plate member made of metal or ceramic, the plate member having a first portion disposed between the plurality of battery cells and the cover in the space, and a second portion provided on the periphery of the first portion and sandwiched between the case main body and the cover.

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 main body with an open upper rectangular box shape and a cover covering the opening of the main body. In such a battery pack, when a battery abnormality occurs and flammable high-pressure gas is generated from the battery cell or a natural fire is caused by the generation of high-pressure gas, there is a concern that the gas may leak from between the main body and the cover or the cover may be damaged by the shock wave accompanying the gas or the natural fire.

[0005] Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a battery pack capable of preventing gas leakage and cover damage with a simple structure.

[0006] [1] A battery pack, wherein the battery pack comprises: a plurality of battery cells; a shell body having an opening; a cover, which is mounted on the shell body in a manner to close the opening and, together with the shell body, forms a space for accommodating the plurality of battery cells; and a plate member, which has a first portion and a second portion and is made of metal or ceramic, wherein the first portion is arranged in the space between the plurality of battery cells and the cover, and the second portion is provided at the periphery of the first portion and is clamped by the shell body and the cover.

[0007] According to the battery pack constructed in this way, the first part of the plate member blocks the gas generated from the battery cell or the shock wave accompanying the natural fire, thereby preventing the cover from being damaged, and further, the second part of the plate member seals the outer shell body and the cover, thereby preventing the gas from leaking. In such a structure, the first part and the second part are integrally provided on the plate member, so that the cover can be prevented from being damaged and the gas from leaking with a simple structure.

[0008] [2] A battery pack as described in [1], wherein the battery cell comprises: an outer casing including a top surface and side surfaces 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 greater than a specified value, and the first portion faces the top surface. Furthermore, the battery pack further comprises a duct, which is arranged to face the side surfaces to form a gas flow path connected to the space to discharge the gas from the space.

[0009] According to the battery pack structured in this way, the first portion disposed between the top surface and the cover can more reliably block the gas flowing out from the inside of the outer body into the space through the top surface. Furthermore, by discharging the gas through the duct, the increase in the internal pressure of the space containing the plurality of battery cells can be suppressed.

[0010] 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

[0011] Figure 1 It is a perspective view showing a battery pack according to an embodiment of the present invention.

[0012] Figure 2 It is shown Figure 1 Exploded assembly diagram of the battery pack in .

[0013] Figure 3 It is a perspective view showing a battery cell.

[0014] Figure 4 It is schematically shown in Figure 1 A cross-sectional view of the battery pack viewed along line IV-IV in the figure. DETAILED DESCRIPTION

[0015] 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.

[0016] Figure 1 It is a perspective view showing a battery pack according to an embodiment 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 It is schematically shown in Figure 1 A cross-sectional view of the battery pack viewed along line IV-IV in the figure.

[0017] Reference Figures 1 to 4The 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).

[0018] 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.

[0019] The battery pack 100 includes a plurality of battery cells 11. The plurality of battery cells 11 are stacked in the Y-axis direction. The battery cells 11 are 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 is the thickness direction of the battery cells 11.

[0020] 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.

[0021] 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 .

[0022] 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.

[0023] 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).

[0024] 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.

[0025] 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.

[0026] In addition, the battery cell in the present invention is not limited to a square shape, but may also be a cylindrical shape. For example, a plurality of battery cells are arranged at intervals in the X-axis-Y-axis plane in an upright position with the cylindrical axis of each battery cell extending in the Z-axis direction. In this case, the gas outflow valve may also be provided on the inner side of the sealing body constituting the top surface of the battery cell.

[0027] like Figure 2 As shown, a plurality of battery cells 11 stacked in the Y-axis direction constitute a cell stack 120. The cell stack 120 has a rectangular parallelepiped shape. The length of the cell stack 120 in the Y-axis direction is greater than the length of the cell stack 120 in the Z-axis direction, and greater than the length of the cell stack 120 in the X-axis direction. The cell stack 120 has a rectangular shape in which the Y-axis direction is the long side direction and the X-axis direction orthogonal to the Y-axis direction is the short side direction when viewed from above along the Z-axis direction.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] The battery pack 100 also has a plate member 41. The plate member 41 is formed of a material having a heat resistance to such an extent that it does not deform even when exposed to high-temperature gas or flames generated by the battery cell 11, and is preferably made of metal or ceramic. The plate member 41 is 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 may also be a member obtained by coating a resin material on the surface of these materials. The thickness of the plate member 41 is smaller than the thickness of the cover 21.

[0037] The plate member 41 includes a first portion 42 and a second portion 46. The first portion 42 and the second portion 46 are integrally formed of metal or ceramic. The first portion 42 and the second portion 46 are connected without interruption. The material of the first portion 42 is the same as that of the second portion 46. The thickness of the first portion 42 is the same as that of the second portion 46.

[0038] The first portion 42 is provided in the space 20. The first portion 42 is disposed between the plurality of battery cells 11 and the cover 21 in the space 20. The first portion 42 is disposed between the cell stack 120 and the cover main body 22 in the space 20. The first portion 42 faces the top surface 15 of the battery cell 11 in the Z-axis direction. The first portion 42 faces the gas outflow valve 17 in the Z-axis direction. The first portion 42 faces the electrode terminal 18 (positive terminal 18P, negative terminal 18N) in the Z-axis direction.

[0039] The first portion 42 has a tray shape with the Z-axis direction being the depth direction and opening downward. The first portion 42 has a rectangular shape with the Y-axis direction being the long side direction and the X-axis direction perpendicular to the Y-axis direction being the short side direction when viewed from above along the Z-axis direction. The range of the single laminate 120 when viewed from above along the Z-axis direction is included in the range of the first portion 42 when viewed from above along the Z-axis direction.

[0040] The second portion 46 is provided at the periphery of the first portion 42. The second portion 46 is provided along the periphery of the first portion 42 when viewed from above in the Z-axis direction. The second portion 46 extends from the lower end of the first portion 42 in a convex shape in the surface direction of the X-axis-Y-axis plane. The second portion 46 is provided in a frame shape along the lower end of the first portion 42.

[0041] The second portion 46 is sandwiched between the housing body 31 and the cover 21. The second portion 46 is inserted between the first flange portion 33 and the second flange portion 24. The second portion 46 receives a tightening force from the plurality of bolts 26 between the first flange portion 33 and the second flange portion 24.

[0042] The space 20 is divided into a space 20A and a space 20B by the plate member 41. The space 20B is surrounded by the plate member 41 and the cover 21. The space 20A is surrounded by the plate member 41 and the casing body 31. A plurality of battery cells 11 are housed in the space 20A.

[0043] The battery pack 100 further includes a duct 70 . The duct 70 is provided facing the first side surface 14 of the battery cell 11 . The duct 70 forms a gas flow path 72 . The gas flow path 72 communicates with the space 20 . The duct 70 discharges the gas flowing out of the gas outflow valve 17 from the space 20 .

[0044] 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.

[0045] 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.

[0046] 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) through the top surface 15 provided with the gas outflow valve 17 ( Figure 4 The gas collides with the plate member 41 and is guided by the first portion 42, thereby flowing 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 4The 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.

[0047] 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 having a first portion 42 and a second portion 46.

[0048] By configuring the first part 42 between the plurality of battery cells 11 (monomer laminate 120) and the cover 21 in the space 20, the high-pressure gas ejected from the battery cell 11 or the shock wave accompanying the natural fire is blocked, thereby preventing the cover 21 from being damaged. In addition, the first part 42 also has a heat shielding function to prevent the cover 21 from being exposed to high-temperature gas. In addition, by clamping the second part 46 between the outer shell body 31 and the cover 21, it is possible to prevent gas from leaking from locations other than the above-mentioned exhaust gas path. In such a structure, since the first part 42 and the second part 46 are integrally provided on the plate member 41, the structure of the battery pack 100 can be simplified.

[0049] In addition, in the present embodiment, the first portion 42 is disposed between the top surface 15 provided with the gas outflow valve 17 and the cover 21 , so that the high-pressure gas flowing out of the gas outflow valve 17 can be more reliably blocked by the first portion 42 .

[0050] To summarize the structure of the battery pack 100 of the embodiment of the present invention described above, the battery pack 100 of the present embodiment includes: a plurality of battery cells 11; a shell body 31 having an opening 30; a cover 21, which is mounted on the shell body 31 in a manner to close the opening 30 and together with the shell body 31 forms a space 20 for accommodating the plurality of battery cells 11; and a plate member 41, which is made of metal or ceramic and has a first portion 42 arranged between the plurality of battery cells 11 and the cover 21 in the space 20 and a second portion 46 provided on the periphery of the first portion 42 and clamped by the shell body 31 and the cover 21.

[0051] According to the battery pack 100 of the embodiment of the present invention configured in this manner, damage to the cover 21 can be prevented with a simple configuration, and leakage of gas from the space 20 can be prevented.

[0052] 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; as well as A plate member having a first portion and a second portion and made of metal or ceramic, wherein the first portion is arranged between the plurality of battery cells and the cover in the space, and the second portion is provided at the periphery of the first portion and sandwiched between the casing body and the cover.

2. The battery pack according to claim 1, wherein: The battery cell has: an outer casing including a top surface and side surfaces and accommodating the electrode body and the electrolyte; and a gas outflow valve for allowing 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 first part faces the top surface. Furthermore, the battery pack further includes a duct, the duct being provided to face the side surface and forming a gas flow path communicating with the space, and discharging the gas from the space.

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