Battery pack

Abstract

To provide a battery pack capable of effectively receiving expansion force of a battery cell and reducing the amount of deformation and generated stress of a case member.SOLUTION: A battery pack includes: a plurality of battery cells arranged side by side in a first direction, each of the plurality of battery cells including a plurality of electrode terminals disposed side by side in a second direction orthogonal to the first direction; and a case member that accommodates the plurality of battery cells, the case member including a side surface portion extending in a direction orthogonal to the first direction or in a direction orthogonal to the second direction and a reinforcing rib provided on the side surface portion. The reinforcing rib extends in a third direction orthogonal to the first direction and the second direction or in a direction obliquely intersecting the third direction.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] This technology relates to a battery pack.

Background Art

[0002] A battery pack in which a plurality of battery cells are housed in a case member has been conventionally known. For example, Japanese Patent Application Laid-Open No. 2019-197622 (Patent Document 1) discloses a battery pack in which a battery stack composed of cells each having a discharge valve is housed in a case. Further, Japanese Patent Application Laid-Open No. 2012-104467 (Patent Document 2) discloses a structure in which reinforcing ribs go around the periphery of the side surface of the battery pack in the lateral direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the swelling force of the battery cell increases, the amount of deformation and the generated stress of the case member also tend to increase. Using a material with a large allowable stress (such as a high-tensile steel plate) to improve the load-bearing capacity becomes a factor in increasing costs. From the viewpoint of suppressing the amount of deformation and the generated stress of the case member due to the swelling force of the battery cell, there is still room for improvement in conventional battery packs.

[0005] An object of the present technology is to provide a battery pack capable of effectively receiving the swelling force of a battery cell and reducing the amount of deformation and the generated stress of a case member.

Means for Solving the Problems

[0006] The battery pack according to the present technology includes a plurality of battery cells each including a plurality of electrode terminals arranged in a first direction and aligned in a second direction orthogonal to the first direction, and a case member that includes side portions extending in a direction orthogonal to the first direction or a direction orthogonal to the second direction and reinforcing ribs provided on the side portions, and houses the plurality of battery cells. The reinforcing ribs extend in a third direction orthogonal to the first direction and the second direction, or in a direction obliquely intersecting the third direction.

Effect of the Invention

[0007] According to the present technology, in the battery pack, it is possible to effectively receive the swelling force of the battery cells and reduce the amount of deformation and the generated stress of the case member.

Brief Description of the Drawings

[0008]

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[0009] Hereinafter, embodiments of the present technology will be described. In addition, the same or corresponding parts may be denoted by the same reference numerals, and the description thereof may not be repeated.

[0010] In the embodiments described below, when referring to the number, amount, etc., unless otherwise specified, the scope of the present technology is not necessarily limited to the number, amount, etc. Also, in the following embodiments, each component is not necessarily essential for the present technology, unless otherwise specified. Further, the present technology is not limited to those that necessarily exhibit all the effects described in the present embodiments.

[0011] In this specification, the descriptions of "comprise", "include", and "have" are in an open - end form. That is, when a certain configuration is included, other configurations outside the said configuration may or may not be included.

[0012] In addition, in this specification, when geometric terms and terms representing positional and directional relationships, such as "parallel", "orthogonal", "45° oblique", "coaxial", "along", etc., are used, these terms allow for manufacturing errors or slight variations. When terms representing relative positional relationships, such as "upper side" and "lower side", are used in this specification, these terms are used to indicate the relative positional relationship in one state, and due to the installation direction of each mechanism (for example, turning the entire mechanism upside down, etc.), the relative positional relationship can be inverted or rotated at any angle.

[0013] In this specification, the "battery" is not limited to lithium-ion batteries and may include other batteries such as nickel-metal hydride batteries and sodium-ion batteries.

[0014] In this specification, the "battery cell" is not necessarily limited to a rectangular shape and may also include cells of other shapes such as cylindrical, pouch-shaped, and blade-shaped. The "battery cell" can be mounted on a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a battery electric vehicle (BEV), etc. However, the use of the "battery cell" is not limited to in-vehicle use.

[0015] Figure 1 is a perspective view showing a battery cell 100. As shown in Figure 1, the battery cell 100 has a rectangular shape. The battery cell 100 has an electrode terminal 110, a housing 120, and a gas discharge valve 130.

[0016] The electrode terminal 110 is formed on the housing 120. The electrode terminal 110 has a positive electrode terminal 111 and a negative electrode terminal 112 arranged along the X-axis direction (the second direction) orthogonal to the Y-axis direction (the first direction). The positive electrode terminal 111 and the negative electrode terminal 112 are provided apart from each other in the X-axis direction.

[0017] The housing 120 has a rectangular parallelepiped shape and forms the exterior of the battery cell 100. The housing 120 includes a case body 120A that houses an electrode body and an electrolytic solution (not shown), and a sealing plate 120B that seals the opening of the case body 120A. The sealing plate 120B is joined to the case body 120A by welding.

[0018] The housing 120 has an upper surface 121, a lower surface 122, a first side surface 123, a second side surface 124, and two third side surfaces 125.

[0019] The upper surface 121 is a plane orthogonal to the Z-axis direction (the third direction) that is orthogonal to the Y-axis direction and the X-axis direction. The electrode terminal 110 is disposed on the upper surface 121. The lower surface 122 faces the upper surface 121 along the Z-axis direction.

[0020] Each of the first side surface 123 and the second side surface 124 consists of a plane orthogonal to the Y-axis direction. Each of the first side surface 123 and the second side surface 124 has the largest area among the plurality of side surfaces of the housing 120. Each of the first side surface 123 and the second side surface 124 has a rectangular shape when viewed in the Y-axis direction. Each of the first side surface 123 and the second side surface 124 has a rectangular shape in which the X-axis direction is the longitudinal direction and the Z-axis direction is the short-side direction when viewed in the Y-axis direction.

[0021] The plurality of battery cells 100 are stacked such that the first side surfaces 123 face each other and the second side surfaces 124 face each other between adjacent battery cells 100, 100 in the Y-axis direction. Thereby, in the Y-axis direction in which the plurality of battery cells 100 are stacked, the positive electrode terminals 111 and the negative electrode terminals 112 are arranged alternately.

[0022] The gas discharge valve 130 is provided on the upper surface 121. When the temperature of the battery cell 100 rises (thermal runaway) and the internal pressure of the housing 120 becomes equal to or higher than a predetermined value due to the gas generated inside the housing 120, the gas discharge valve 130 discharges the gas to the outside of the housing 120.

[0023] Figures 2 and 3 are perspective views showing a case member 200 for housing the battery cell 100. In Figures 2 and 3, for the sake of illustration, the lid portion of the case member 200 described later is not shown.

[0024] As shown in Figures 2 and 3, the case member 200 includes an internal space 200A, a bottom member 210, a cooling plate 220, side members 230, and reinforcing ribs 240.

[0025] In the internal space 200A, a stack (battery pack) of a plurality of battery cells 100 laminated in the Y-axis direction is housed. The battery pack is provided so as to be arranged in three rows in the X-axis direction. The cooling plate 220 and the side members 230 define the internal space 200A.

[0026] The bottom member 210 and the cooling plate 220 constitute the bottom of the case member 200. The cooling plate 220 is provided on the bottom member 210. The cooling plate 220 includes a first portion 221 facing the internal space 200A and a second portion 222 located outside the first portion 221 and not facing the internal space 200A.

[0027] The side member 230 includes an upper flange portion 231 (first flange), a lower flange portion 232 (second flange), and a side portion 233 (frame portion). The second portion 222 of the cooling plate 220 is sandwiched between the lower flange portion 232 of the side member 230 and the bottom member 210. The side portion 233 of the side member 230 constitutes the side surface of the case member 200. The side portion 233 includes a portion extending in a direction orthogonal to the Y-axis direction and a portion extending in a direction orthogonal to the X-axis direction. The side portion 233 connects the upper flange portion 231 and the lower flange portion 232. The upper flange portion 231 (first flange), the lower flange portion 232 (second flange), and the side portion 233 (frame portion) form a U-shaped cross-section. The side portion 233 located on both sides of the stack of battery cells 100 (including the separator) in the Y-axis direction and extending in a direction orthogonal to the Y-axis direction directly supports the stack of battery cells 100 (Cell-to-Pack structure). At the α portion of the side portion 233 in Figure 3, the stack of battery cells 100 abuts against the side portion 233.

[0028] However, the case member 200 is not limited to the one in which the side surface portion 233 directly supports the stacked body of the battery cells 100, and may be one that houses a battery module including a plurality of battery cells 100 (Cell-Module-Pack structure).

[0029] The reinforcing rib 240 is provided on the side surface portion 233 extending in a direction orthogonal to the Y-axis direction. The reinforcing rib 240 may be provided on the side surface portion 233 extending in a direction orthogonal to the X-axis direction. The reinforcing rib 240 is provided so as to extend in the Z-axis direction. The reinforcing rib 240 may be provided so as to extend in a direction obliquely intersecting the Z-axis direction.

[0030] On the side surface portion 233 extending in a direction orthogonal to the Y-axis direction, a plurality of reinforcing ribs 240 are provided so as to be arranged in the X-axis direction. The reinforcing rib 240 may be singular.

[0031] On the side surface portion 233, the reinforcing rib 240 extends over the entire Z-axis direction. The reinforcing rib 240 may be provided over a part of the Z-axis direction.

[0032] The lower flange portion 232 abuts on the second portion 222 of the cooling plate 220. The upper flange portion 231 is formed at the upper end portion of the side surface member 230, that is, at the end portion on the opposite side of the Z-axis direction with respect to the cooling plate 220. The upper flange portion 231 is spaced apart from the second portion 222 of the cooling plate 220 and the lower flange portion 232 along the Z-axis direction, and is formed in parallel with the second portion 222 and the lower flange portion 232. The upper flange portion 231 protrudes from the side surface portion 233 in the same direction as the second portion 222 of the cooling plate 220 and the lower flange portion 232. The second portion 222 of the cooling plate 220 protrudes outside the side surface portion 233 of the side surface member 230.

[0033] The reinforcing rib 240 is formed so as to reach from the upper flange portion 231 to the lower flange portion 232. The reinforcing rib 240 may be made of the same material as the side member 230, or may be made of a material different from that of the side member 230. The reinforcing rib 240 may be made of, for example, a steel plate, may be made of aluminum, or may be made of resin. The reinforcing rib 240 is joined to the upper flange portion 231, the side surface portion 233, and the lower flange portion 232. This joining is performed by, for example, welding. Preferably, all portions where the reinforcing rib 240 and the side member 230 face each other are welded.

[0034] FIG. 4 is a side view of the case member 200. As shown in FIG. 4, the reinforcing rib 240 includes a first rib 241, a second rib 242, a third rib 243, and a fourth rib 244. The first rib 241, the second rib 242, the third rib 243, and the fourth rib 244 are provided so as to be spaced apart from each other along the X-axis direction.

[0035] The second rib 242 is provided on the central axis in the X-axis direction of the stack of battery cells 100 located at the center among the three rows. The second rib 242 is disposed at a distance B from the side surface portion 233 (reference side surface for rib arrangement) on the left side in FIG. 4. The second rib 242 is located on the central axis of the battery cells 100 located at the center among the three rows.

[0036] The first rib 241 is disposed at a distance B / 2 from the side surface portion 233 on the left side in FIG. 4. The first rib 241 is provided at a position corresponding to the stack of battery cells 100 located on the left side in the figure among the three rows, but is provided at a position spaced apart from the central axis of the battery cells 100.

[0037] The third rib 243 is disposed at a distance B / 2 from the second rib 242. The third rib 243 is provided at a position corresponding to the stack of battery cells 100 located on the right side in the figure among the three rows, but is provided at a position spaced apart from the central axis of the battery cells 100.

[0038] The fourth rib 244 is arranged at a distance D from the third rib 243. The distance D is different from the distance B / 2. The fourth rib 244 is provided at a position separated from the central axis of the battery cell 100. Preferably, the fourth rib 244 is along the edge or its vicinity on the far side (the right side in FIG. 4) from the reference side surface of the α portion (the rightmost α portion among the three α portions shown in FIG. 4) where the stacked body of the battery cells 100 that is farthest from the left side surface portion 233 (the reference side surface for rib reinforcement arrangement) in FIG. 4 abuts.

[0039] FIG. 5 is an external view of the battery pack. As shown in FIG. 5, a lid member 250 is assembled to the side surface member 230, and the internal space 200A of the case member 200 is sealed. The battery pack includes an inlet portion 300, an outlet portion 400, and a refrigerant pipe 500. Refrigerant is supplied from the inlet portion 300 through the refrigerant pipe 500 to the refrigerant passage formed inside the cooling plate 220, and the refrigerant is discharged from the outlet portion 400 through the refrigerant pipe 500. Although water is used as the refrigerant, it is not limited thereto.

[0040] The refrigerant pipe 500 is provided so as to extend along the side surface portion 233. The refrigerant pipe 500 is supported by a support portion 2400 provided on the reinforcing rib 240. The support portion 2400 can be constituted by a through hole provided in the reinforcing rib 240.

[0041] FIGS. 6 to 15 are diagrams showing examples of the arrangement of the reinforcing rib 240. In the example shown in FIG. 6, similar to the examples in FIGS. 2 to 5, the first rib 241, the second rib 242, the third rib 243, and the fourth rib 244 are arranged for the stacked body of the three rows of battery cells 100.

[0042] In the examples shown in FIGS. 7 to 9, a stack of four columns of battery cells 100 is provided. In the example of FIG. 7, the first rib 241 and the second rib 242 are arranged at positions avoiding the battery cell 100. In the example of FIG. 8, the first rib 241, the second rib 242, the third rib 243, and the fourth rib 244 are arranged at positions avoiding the battery cell 100. In the example of FIG. 9, the first rib 241, the third rib 243, the fifth rib 245, and the seventh rib 247 are arranged on the central axis of the battery cell 100, and the second rib 242, the fourth rib 244, the sixth rib 246, and the eighth rib 248 are arranged at positions avoiding the battery cell 100.

[0043] In the examples shown in FIGS. 10 to 12, a stack of five columns of battery cells 100 is provided. In the example of FIG. 10, the first rib 241 is arranged on the central axis of the battery cell 100, and the second rib 242 is arranged at a position avoiding the battery cell 100. In the example of FIG. 11, the second rib 242 is arranged on the central axis of the battery cell 100, and the first rib 241 and the third rib 243 are arranged at positions corresponding to the battery cell 100 but spaced apart from the central axis of the battery cell 100, and the fourth rib 244 is arranged at a position avoiding the battery cell 100. In the example of FIG. 12, the fourth rib 244 is arranged on the central axis of the battery cell 100, and the first rib 241, the second rib 242, the fifth rib 245, the sixth rib 246, and the seventh rib 247 are arranged at positions corresponding to the battery cell 100 but spaced apart from the central axis of the battery cell 100, and the third rib 243 and the eighth rib 248 are arranged at positions avoiding the battery cell 100.

[0044] In the examples shown in FIGS. 13 to 15, a stack of six columns of battery cells 100 is provided. In the example of FIG. 13, the first rib 241 and the second rib 242 are arranged at positions avoiding the battery cell 100. In the example of FIG. 14, the first rib 241 and the third rib 243 are arranged on the central axis of the battery cell 100, and the second rib 242 and the fourth rib 244 are arranged at positions avoiding the battery cell 100. In the example of FIG. 15, the second rib 242 and the sixth rib 246 are arranged on the central axis of the battery cell 100, and the first rib 241, the third rib 243, the fifth rib 245, and the seventh rib 247 are arranged at positions corresponding to the battery cell 100 but separated from the central axis of the battery cell 100, and the fourth rib 244 and the eighth rib 248 are arranged at positions avoiding the battery cell 100.

[0045] Thus, depending on the number of columns of the stack of battery cells 100 (whether even or odd, and if even, whether the number divided by 2 is even or odd), and the number of reinforcing ribs 240 (which can be appropriately changed), all the reinforcing ribs 240 may be arranged outside the center of the pressure-receiving surface (the central axis in the X-axis direction of the battery cell 100), or some of the reinforcing ribs 240 may be arranged outside the center of the pressure-receiving surface. In either case, the inventors of the present application have confirmed that, as compared with the case where the reinforcing ribs 240 are arranged only at the center of the pressure-receiving surface, the swelling force of the battery cell 100 in the Y-axis direction can be effectively and uniformly received, and the amount of deformation and the generated stress of the side surface portion 233 of the case member 200 can be reduced.

[0046] Preferably, taking the distance between the central axis in the X-axis direction of the stack of multiple columns of battery cells 100 in the case member 200 and the side surface portion 233 (the reference side surface for arranging the reinforcing ribs) of the case member 200 along the Y-axis direction as the reference distance (B), and obtaining the reinforcing rib arrangement distance (B / 2) as half (or 1 / 4, 1 / 8, etc., the reciprocal of an integer) of the reference distance, a plurality of reinforcing ribs 240 are sequentially arranged at intervals of the reinforcing rib arrangement distance from the reference side surface for arranging the reinforcing ribs. More preferably, the reinforcing ribs 240 are arranged along the edge of the α portion where the stack of battery cells 100 farthest from the reference side surface for arranging the reinforcing ribs abuts, specifically, along the edge on the side far from the reference side surface or in its vicinity.

[0047] FIG. 16 is a perspective view showing a modified example of the case member 200 (excluding the lid member 250). As shown in FIG. 16, in addition to the reinforcing rib 240 extending in the Z-axis direction, a reinforcing rib 240A extending in the X-axis direction (or the Y-axis direction) may be provided. Further, in addition to the reinforcing rib extending in a direction inclined obliquely with respect to the Z-axis direction, a reinforcing rib 240A extending in the X-axis direction (or the Y-axis direction) may be provided.

[0048] By adding the reinforcing rib 240A, the amount of deformation of the side surface portion 233 of the case member 200 can be more effectively suppressed. In addition, the structure and arrangement of the reinforcing rib 240 are not necessarily limited to those described above. For example, a plurality of reinforcing ribs 240 may be arranged at equal intervals, or the intervals between the plurality of reinforcing ribs 240 may be different from each other.

[0049] FIG. 17 is an enlarged view of the support portion 2400 of the refrigerant pipe 500. In the example of FIG. 17, the support portion 2400 is constituted by a substantially circular through-hole provided in the reinforcing rib 240. The shape of the through-hole can be appropriately changed. A cushioning material may be provided at the contact portion between the support portion 2400 and the refrigerant pipe 500.

[0050] As described above, the embodiments of the present technology have been described. It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present technology is indicated by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims be included.

Description of Reference Numerals

[0051] 100 battery cell, 110 electrode terminal, 111 positive electrode terminal, 112 negative electrode terminal, 120 housing, 120A case body, 120B sealing plate, 121 upper surface, 122 lower surface, 123 first side surface, 124 second side surface, 125 third side surface, 130 gas discharge valve, 200 case member, 200A internal space, 210 bottom member, 220 cooling plate, 221 first portion, 222 second portion, 230 side member, 231 upper flange portion, 232 lower flange portion, 233 side portion, 240, 240A reinforcing rib, 241 first rib, 242 second rib, 243 third rib, 244 fourth rib, 245 fifth rib, 246 sixth rib, 247 seventh rib, 248 eighth rib, 250 lid member, 300 inlet portion, 400 outlet portion, 500 refrigerant pipe, 2400 support portion.

Claims

1. A plurality of battery cells each including a plurality of electrode terminals arranged in a first direction and aligned in a second direction orthogonal to the first direction; A case member that includes a sealed internal space for housing the plurality of battery cells, a side surface portion extending in a direction orthogonal to the first direction, and a reinforcing rib provided on the side surface portion, and that houses the plurality of battery cells; A laminate of the plurality of battery cells including separators abuts against the side surface portion, and the side surface portion directly supports the laminate of the plurality of battery cells; The reinforcing rib is provided so as to be located outside the case member in a state where the internal space is sealed, and extends in a third direction orthogonal to the first direction and the second direction, or in a direction obliquely intersecting the third direction; The reinforcing rib is provided on the side surface portion of the case member located on both sides of the plurality of battery cells in the first direction, and the side surface portion of the case member located on both sides of the plurality of battery cells in the first direction directly supports the laminate, a battery pack.

2. The reinforcing rib extends over the entire third direction on the side surface portion of the case member, the battery pack according to claim 1.

3. A plurality of battery cells each including a plurality of electrode terminals arranged in a first direction and aligned in a second direction orthogonal to the first direction; A case member that includes a side surface portion extending in a direction orthogonal to the first direction and a reinforcing rib provided on the side surface portion, and that houses the plurality of battery cells; A laminate of the plurality of battery cells including separators abuts against the side surface portion, and the side surface portion directly supports the laminate of the plurality of battery cells; The reinforcing rib extends in a third direction orthogonal to the first direction and the second direction, or in a direction obliquely intersecting the third direction; The case member includes a first flange and a second flange that protrude from the side surface portion in the first direction and extend in the second direction; The first flange and the second flange are formed to be spaced apart from each other along the third direction. The reinforcing rib is formed to reach from the first flange to the second flange. The reinforcing rib is provided on the side surface portion of the case member located on both sides of the plurality of battery cells in the first direction, and the side surface portion of the case member located on both sides of the plurality of battery cells in the first direction directly supports the laminate, a battery pack.

4. The reinforcing rib is joined to the first flange and the second flange, the battery pack according to claim 3.

5. A plurality of battery cells each including a plurality of electrode terminals arranged in a first direction and aligned in a second direction orthogonal to the first direction, A case member including a side surface portion extending in a direction orthogonal to the first direction and a reinforcing rib provided on the side surface portion, for housing the plurality of battery cells, The reinforcing rib extends in a third direction orthogonal to the first direction and the second direction, or in a direction obliquely intersecting the third direction, The plurality of battery cells have a housing including a plurality of side surfaces, and the plurality of battery cells are stacked such that the side surfaces having the largest area among the plurality of side surfaces face each other, A laminate of the plurality of battery cells including separators is provided so as to be arranged in a plurality of rows in the second direction, The side surface portion of the case member abuts on the laminate of the plurality of battery cells and supports the laminate of the plurality of battery cells in the first direction. The reinforcing rib is provided on the side surface portion of the case member located on both sides of the plurality of battery cells in the first direction, and the side surface portion of the case member located on both sides of the plurality of battery cells in the first direction directly supports the laminate, a battery pack.

6. The battery pack according to any one of claims 1 to 5, wherein the reinforcing rib is provided at a position spaced apart from the central axis of the plurality of battery cells in the second direction.

7. The battery pack according to any one of claims 1 to 6, wherein the reinforcing rib is made of the same material as the side surface portion of the case member.

8. A plurality of battery cells each including a plurality of electrode terminals arranged in a first direction and aligned in a second direction orthogonal to the first direction, A case member including a side surface portion extending in a direction orthogonal to the first direction and a reinforcing rib provided on the side surface portion, and housing the plurality of battery cells, A stack of the plurality of battery cells including separators abuts against the side surface portion, and the side surface portion directly supports the stack of the plurality of battery cells, The reinforcing rib extends in a third direction orthogonal to the first direction and the second direction, or in a direction obliquely intersecting the third direction, A cooling plate including a refrigerant passage, The battery pack further includes a refrigerant pipe communicating with the refrigerant passage of the cooling plate. The reinforcing rib includes a support portion for supporting the refrigerant pipe. The reinforcing rib is provided on the side surface portions of the case member located on both sides of the plurality of battery cells in the first direction, and the side surface portions of the case member located on both sides of the plurality of battery cells in the first direction directly support the stack.

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