JP7597085B2 - Battery pack case - Google Patents

Description

The present invention relates to a battery pack case.

Patent document 1 discloses a battery pack case that houses multiple batteries stacked in a first direction and constrains the multiple batteries in the first direction.

JP 2020-129474 A

However, in this type of battery pack case, the restraining load in the first direction of the multiple batteries may fluctuate due to, for example, the SOC (States Of Charge) or temperature changes, which may result in a loss of stable battery performance.

The present invention was made in consideration of the above problems, and its purpose is to provide a battery pack case that can better suppress fluctuations in the restraining load of multiple batteries.

In order to solve the above-mentioned problems and achieve the object, the battery pack case according to the present invention is a battery pack case that houses a plurality of batteries stacked in a first direction and restrains the plurality of batteries in the first direction, and includes a first sheet metal having a pair of first metal parts facing the batteries on both sides in the first direction and a pair of second metal parts extending between the pair of first metal parts, a second sheet metal having a pair of third metal parts positioned on the opposite side of the first metal parts from the batteries in the first direction, a pair of first resin parts interposed between the first metal parts and the third metal parts, a pair of second resin parts positioned on the opposite side of the third metal parts from the first resin parts in the first direction so as to sandwich the third metal parts therebetween, and a pair of third resin parts extending between the pair of first resin parts and between the pair of second resin parts.

According to the present invention, the difference in the linear expansion coefficient between the first and second metal sheets and the resin member can be utilized to suppress the increase or decrease in the restraining load of the multiple batteries due to the load generated at the interface between the first and second metal sheets and the resin member. For example, when the multiple batteries expand in the first direction during a high temperature transition or high SOC, the expansion of the resin member spreads the first and second metal sheets toward both sides in the first direction, thereby suppressing the increase in the restraining load of the multiple batteries in the first direction. Also, when the multiple batteries shrink in the first direction during a low temperature transition or low SOC, the contraction of the resin member pulls the first and second metal sheets toward the center in the first direction, thereby suppressing the decrease in the restraining load of the multiple batteries in the first direction. As a result, a battery pack case can be provided that can further suppress the fluctuation in the restraining load of the multiple batteries.

FIG. 1 is an exemplary schematic cross-sectional view of a battery pack to which a battery pack case according to an embodiment is applied. FIG. 2 is an exemplary schematic cross-sectional view of a resin member of a battery pack case according to an embodiment.

The following describes exemplary embodiments of the present invention. The configuration of the embodiment described below, and the actions and effects brought about by said configuration, are merely examples. Note that in this specification, ordinal numbers are used only to distinguish between parts, members, parts, positions, directions, etc., and do not indicate order or priority.

[Embodiment]
1 is a schematic cross-sectional view of a battery pack 1 to which a battery pack case 10 according to an embodiment is applied. In the following description, for convenience, three mutually orthogonal directions are defined. The X direction is along the front-rear direction (vertical width) of the battery pack case 10, the Y direction is along the left-right direction (horizontal width) of the battery pack case 10, and the Z direction is along the up-down direction of the battery pack case 10.

As shown in FIG. 1, the battery pack 1 is an in-vehicle battery pack that is mounted, for example, on an electric vehicle, and includes a plurality of battery cells 2, a spacer 3, and a battery pack case 10 that houses the plurality of battery cells 2 and the spacer 3 in a compressed and restrained state in the Y direction. In this embodiment, the Y direction is an example of a first direction, and the battery cells 2 are an example of a battery.

The battery cells 2 are, for example, rectangular can-type lithium ion secondary batteries. The multiple battery cells 2 are stacked in the Y direction in a vertical orientation, i.e., with each terminal surface facing one side in the Z direction. The multiple battery cells 2 are connected in series or parallel via bus bars (not shown) or the like.

The spacer 3 is, for example, a plate-shaped member made of insulating resin. The spacer 3 is interposed between the battery cells 2 on both sides in the Y direction and the battery pack case 10, and between two battery cells 2 adjacent in the Y direction, to insulate the battery cells 2 from each other. In this embodiment, multiple battery cells 2 and spacers 3 are stacked alternately in the Y direction inside the battery pack case 10.

The battery pack case 10 is configured, for example, in the shape of a rectangular parallelepiped box elongated in the Y direction. The battery pack case 10 has multiple walls, such as a bottom wall 10c, a top wall (not shown), a pair of end walls 10a, a pair of side walls 10b, and a middle wall 10d. The bottom wall 10c is also referred to as a lower wall, and the top wall is also referred to as an upper wall. The end walls 10a and the side walls 10b are also referred to as peripheral walls or side walls, and the middle wall 10d is also referred to as a partition wall.

The bottom wall 10c and the top wall both extend in a direction perpendicular to the Z direction (XY plane) and are arranged parallel to each other with a gap in the Z direction. The bottom wall 10c forms the lower end of the battery pack case 10, and the top wall forms the upper end of the battery pack case 10. The bottom wall 10c supports the lower surfaces of each of the battery cells 2.

The pair of end walls 10a each extend along a direction perpendicular to the Y direction (XZ plane) and are arranged parallel to each other with a gap in the Y direction. One of the end walls 10a forms the left end of the battery pack case 10, and the other forms the right end of the battery pack case 10. The pair of end walls 10a support the Y-direction side surfaces of each of the battery cells 2.

The pair of side walls 10b each extend along a direction perpendicular to the X direction (YZ plane) and are arranged parallel to each other with a gap in the X direction. One of the side walls 10b forms the front end of the battery pack case 10, and the other forms the rear end of the battery pack case 10. The pair of side walls 10b support the X-direction side surfaces of each of the battery cells 2.

The middle wall 10d is located between a pair of side walls 10b and extends parallel to the side walls 10b between a pair of end walls 10a. The middle wall 10d divides the inside of the battery pack case 10 into a plurality of spaces (battery chambers) in the X direction. In this embodiment, the plurality of battery cells 2 includes a first stack 2A stacked in the Y direction in one space in the X direction from the middle wall 10d, and a second stack 2B stacked in the Y direction in the other space in the X direction from the middle wall 10d. The first stack 2A and the second stack 2B are also referred to as a battery cell row, a battery cell group, a battery cell assembly, etc.

The battery pack case 10 is configured as a so-called multi-material case that combines multiple sheet metal members, such as a first metal sheet 11, a second metal sheet 12, and a third metal sheet 13, and members such as a resin member 14. The battery pack case 10 is formed by integrating the resin member 14 with the first metal sheet 11, the second metal sheet 12, and the third metal sheet 13, for example, by insert molding, two-color molding, or the like.

The first metal sheet 11 has, for example, multiple metal parts 11a to 11d. The metal part 11c is configured as a rectangular plate extending along a direction (XY plane) perpendicular to the Z direction. The metal part 11c forms the bottom wall 10c of the battery pack case 10 described above.

The metal parts 11a are provided at both ends of the metal part 11c in the Y direction, and are configured as rectangular plates extending along a direction perpendicular to the Y direction (XZ plane). The pair of metal parts 11a form the end walls 10a of the battery pack case 10 described above, and face the battery cells 2 on both sides in the Y direction via the spacers 3. The metal parts 11a are an example of a first metal part.

Metal part 11b is provided at both ends of metal part 11c in the X direction and is configured as a rectangular plate extending along a direction perpendicular to the X direction (YZ plane). The pair of metal parts 11b configures the side walls 10b of the battery pack case 10 described above and extends between the pair of metal parts 11a. Metal part 11b is an example of a second metal part.

Metal part 11d is provided in the center of metal part 11c in the X direction and is configured as a rectangular plate extending along a direction perpendicular to the X direction (YZ plane). Metal part 11d constitutes the middle wall 10d of the battery pack case 10 described above and extends between the pair of metal parts 11a.

The second metal sheets 12 are provided on both sides of the multiple battery cells 2 in the Y direction. Specifically, in this embodiment, four second metal sheets 12 are provided at the four corners of the battery pack case 10 corresponding to the first stack 2A and the second stack 2B of the multiple battery cells 2. Each of the second metal sheets 12 has, for example, multiple metal parts 12a, 12b.

The metal part 12a is configured as a rectangular plate extending along the metal part 11a. The metal part 12a, together with the metal part 11a, configures the end wall 10a of the battery pack case 10, and is positioned on the opposite side of the metal part 11a from the battery cell 2 in the Y direction. The metal part 12a is an example of a third metal part.

The metal parts 12b are provided at both ends of the metal part 12a in the X direction and are configured as rectangular plates extending along the metal part 11b. The pair of metal parts 12b, together with the metal part 11b, constitute the side wall 10b of the battery pack case 10, and together with the metal part 11d, constitute the middle wall 10d of the battery pack case 10. The second metal sheet 12 is fixed to the first metal sheet 11 by fasteners such as screws and bolts.

The third metal sheets 13 are provided on both sides of the second metal sheets 12 in the Y direction. The pair of third metal sheets 13 are configured as rectangular plates extending along the metal parts 11a, 12a, and together with the metal parts 11a, 12a, form the end wall 10a of the battery pack case 10. The third metal sheets 13 are fixed to the second metal sheets 12 by fasteners such as screws and bolts.

Figure 2 is a schematic cross-sectional view of the resin member 14 of the battery pack case 10. As shown in Figure 2, the resin member 14 has, for example, multiple resin parts 14a to 14d. The resin part 14a is provided on both sides of the multiple battery cells 2 in the Y direction. The pair of resin parts 14a are interposed between the metal part 11a and the metal part 12a described above, and together with the metal parts 11a and 12a, form the end wall 10a of the battery pack case 10. The resin part 14a is an example of a first resin part.

The resin parts 14b are provided on both sides of the pair of resin parts 14a in the Y direction, and together with the above-mentioned metal parts 11a and 12a, they form the end wall 10a of the battery pack case 10. The pair of resin parts 14b are positioned on the opposite side of the metal part 12a to the resin part 14a in the Y direction, sandwiching the metal part 12a therebetween. In other words, the metal part 12a is interposed between the resin parts 14a and 14b, and the resin part 14b is interposed between the metal part 12a and the third sheet metal 13. The resin parts 14b are an example of a second resin part.

The resin portion 14c is provided at both ends of the resin portion 14b in the X direction, and extends between the pair of resin portions 14a and between the pair of resin portions 14b. That is, the resin portion 14c is connected to each of the resin portions 14a and 14b. The resin portion 14c, together with the above-mentioned metal portions 11b and 12b, constitutes the side wall 10b of the battery pack case 10. The resin portion 12c is an example of a third resin portion.

The resin portion 14d is provided in the center of the resin portion 14b in the X direction and extends between the pair of resin portions 14a and between the pair of resin portions 14b. That is, the resin portion 14d is connected to each of the resin portions 14a and 14b. The resin portion 14c, together with the above-mentioned metal portions 11d and 12b, constitutes the inner wall 10d of the battery pack case 10.

As described above, according to the present embodiment, the battery pack case 10 includes the first sheet metal 11, the second sheet metal 12, and the resin member 14. By utilizing the difference in the linear expansion coefficients between the first sheet metal 11 and the second sheet metal 12 and the resin member 14, the load generated at the interface between the first sheet metal 11 and the second sheet metal 12 and the resin member 14 can be used to suppress an increase or decrease in the restraining load of the multiple battery cells 2. For example, when the multiple battery cells 2 expand in the Y direction during a high temperature transition or a high SOC, the expansion of the resin member 14 pushes the first sheet metal 11 and the second sheet metal 12 toward both sides in the Y direction, thereby suppressing an increase in the restraining load of the multiple battery cells 2 in the Y direction. In addition, when the multiple battery cells 2 shrink in the Y direction during a low temperature transition or a low SOC, the contraction of the resin member 14 pulls the first sheet metal 11 and the second sheet metal 12 toward the center in the Y direction, thereby suppressing a decrease in the restraining load of the multiple battery cells 2 in the Y direction. As a result, it is possible to provide a battery pack case 10 that can further suppress fluctuations in the restraining load of multiple battery cells 2.

Although the above describes an embodiment of the present invention, the above embodiment is merely an example and is not intended to limit the scope of the invention. The above embodiment can be implemented in various other forms, and various omissions, substitutions, combinations, and modifications can be made without departing from the spirit of the invention.

1...battery pack, 2...battery cell (battery), 10...battery pack case, 11...first metal sheet, 11a...metal part (first metal part), 11b...metal part (second metal part), 12...second metal sheet, 12a...metal part (third metal part), 14...resin member, 14a...resin part (first resin part), 14b...resin part (second resin part), 14c...resin part (third resin part), Y...first direction.

Claims (1)

A battery pack case that houses a plurality of batteries stacked in a first direction and constrains the plurality of batteries in the first direction,
A first metal plate having a pair of first metal portions facing the battery on both sides in the first direction and a pair of second metal portions extending between the pair of first metal portions;
A second sheet metal having a pair of third metal parts positioned on the opposite side of the first metal part from the battery in the first direction;
a resin member including: a pair of first resin parts interposed between the first metal part and the third metal part; a pair of second resin parts positioned on the opposite side of the third metal part to the first resin parts in the first direction so as to sandwich the third metal part therebetween; and a pair of third resin parts extending between the pair of first resin parts and between the pair of second resin parts;
A battery pack case equipped with

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