Battery pack

Abstract

To provide a battery pack having a structure that can reduce direct input of impact load from an extending direction to battery cells by using a simple structure.SOLUTION: A battery pack is mounted on a vehicle. The battery pack comprises a plurality of laminated battery cells, and an intermediate plate. The intermediate plate is arranged between at least a pair of adjacent battery cells included in the plurality of battery cells. The plurality of battery cells and the intermediate plate are accommodated in a case of the battery pack. In an extending direction orthogonal to a lamination direction of the plurality of battery cells, the intermediate plate is longer than a plurality of battery cells.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a battery pack mounted on a vehicle. [Background technology]

[0002] Patent Document 1 discloses a battery pack arranged between a pair of side sills (framework members) of a vehicle. This battery pack is arranged between two battery modules (battery stacks) lined up in the vehicle width direction and includes a load transmission member with a hollow portion. When an impact load is input to the side sills, this load transmission member deforms in the vehicle width direction to absorb the collision energy and reduce the load acting on the battery module located on the opposite side of the impact load input side in the vehicle width direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-197047 Summary of the Invention [Problem to be solved by the invention]

[0004] With the load transmission member used in the battery pack structure described in Patent Document 1, it is considered difficult to reduce the direct input to the battery module (multiple battery cells) when an impact load is input to the case from the extension direction, which is a direction perpendicular to the stacking direction of the battery module.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a battery pack having a structure that can reduce the direct input of impact load from the extension direction to the battery cells using a simple structure. [Means for solving the problem]

[0006] A battery pack according to the present disclosure is mounted on a vehicle and includes a plurality of stacked battery cells and an intermediate plate. The intermediate plate is disposed between at least one pair of adjacent battery cells included in the plurality of battery cells. The plurality of battery cells and the intermediate plate are housed in a battery pack case. The intermediate plate is longer than the plurality of battery cells in an extension direction perpendicular to the stacking direction of the plurality of battery cells.

[0007] The battery pack may further include a pair of end plates disposed in the case on both ends of the plurality of battery cells in the stacking direction, and the intermediate plate may have the same or substantially the same length as the pair of end plates in the extension direction.

[0008] The intermediate plate may be disposed approximately in the center of the plurality of battery cells in the stacking direction.

[0009] There may be a plurality of intermediate plates, which are arranged at equal intervals between the plurality of battery cells in the stacking direction.

[0010] The plurality of battery cells may include a plurality of battery stacks, which are stacks of a plurality of battery cells stacked in a stacking direction. The plurality of battery stacks may be arranged at intervals in the extension direction. At least one intermediate plate may be arranged in each of the plurality of battery stacks. A pair of end plates may be arranged for each of the plurality of battery stacks.

[0011] The case may include a skeletal structural member disposed between at least one pair of adjacent battery stacks included in the plurality of battery stacks and extending in the stacking direction to form a skeleton of the case, and the intermediate plate and the pair of end plates may face the skeletal structural member in the extension direction.

[0012] The intermediate plate may be bonded to the case.

[0013] The lamination direction may be the width direction of the vehicle, and the stretching direction may be the front-rear direction of the vehicle. [Effects of the Invention]

[0014] As described above, the battery pack according to the present disclosure includes an intermediate plate disposed between at least one pair of adjacent battery cells included in the plurality of battery cells. The intermediate plate is longer than the plurality of battery cells in the extension direction. This structure allows the intermediate plate to absorb an impact load from the extension direction before the plurality of battery cells. Therefore, a simple structure can be used to reduce the direct input of the impact load from the extension direction to the battery cells. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a diagram schematically illustrating a structure of a battery pack according to an embodiment. [Figure 2] 10A to 10C are diagrams for explaining the effect of the structure of the battery pack according to the embodiment. [Figure 3] 10A and 10B are diagrams illustrating an example of the arrangement of an intermediate plate according to a modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the embodiments described below, when the number, quantity, amount, range, etc. of each element is mentioned, the technical idea of ​​the present disclosure is not limited to the mentioned numbers unless otherwise specified or clearly specified in principle. Furthermore, the structures, etc. described in the embodiments described below are not necessarily essential to the technical idea of ​​the present disclosure unless otherwise specified or clearly specified in principle.

[0017] 1. Battery pack structure FIG. 1 is a diagram schematically illustrating the structure of a battery pack 10 according to an embodiment. The battery pack 10 includes a plurality of battery cells 12 and a case 14. The case 14 houses the battery cells 12 together with an intermediate plate 18 and end plates 20, which will be described later. The case 14 has, for example, a substantially rectangular parallelepiped shape. The battery pack 10 is mounted on a vehicle and supplies power to an electric motor for driving the vehicle. The case 14 is fixed to a structural member of the vehicle. FIG. 1 shows the internal structure of the battery pack 10 as viewed from above the vehicle.

[0018] In the battery pack 10, the plurality of battery cells 12 are formed in a plate shape and are stacked along a stacking direction D1. In the example shown in Fig. 1, the stacking direction D1 is parallel to the vehicle width direction (vehicle left-right direction).

[0019] Specifically, the multiple battery cells 12 include multiple battery stacks 16, which are stacks of multiple battery cells 12 stacked in a stacking direction D1. Such battery stacks are also called battery stacks. In the example shown in FIG. 1, each battery stack 16 is a stack of ten battery cells 12. Four such battery stacks 16 are arranged. These battery stacks 16 are spaced apart in an extension direction D2. The extension direction D2 is the extension direction of the intermediate plate 18 and is perpendicular to the stacking direction D1. In the example shown in FIG. 1, the extension direction D2 corresponds to the longitudinal direction of the vehicle.

[0020] Each battery stack 16 is arranged in a row together with an intermediate plate 18 and a pair of end plates 20. In each battery stack 16, the intermediate plate 18 is disposed between adjacent battery cells 12. As an example, one intermediate plate 18 is disposed (interposed) in each of the four battery stacks 16. As shown in FIG. 1 , the intermediate plate 18 is disposed approximately in the center of the plurality of battery cells 12 in the stacking direction D1. The four battery stacks 16 are electrically connected in series.

[0021] In each battery stack 16, a pair of end plates 20 is arranged at both ends of the multiple battery cells 12 in the stacking direction D1. That is, the pair of end plates 20 face each other so as to sandwich the battery stack 16 from both sides in the stacking direction D1. A pair of end plates 20 is arranged for each of the four battery stacks 16.

[0022] To stably secure the battery stack 16 to the case 14, the battery stack 16 and the pair of end plates 20, with the intermediate plate 18 interposed therebetween, are bound together by restraint bands 22. The restraint bands 22 are metal plates. For each battery stack 16, the restraint bands 22 are arranged on both sides in the vehicle's longitudinal direction, for example. Both ends of each restraint band 22 are fastened to the pair of end plates 20 via fasteners (not shown). More specifically, as shown in FIG. 1 , each restraint band 22 is in contact with the intermediate plate 18 and the pair of end plates 20, but, for example, a gap is provided between each restraint band 22 and each battery cell 12.

[0023] The pair of end plates 20 are fastened to the case 14 via fasteners (not shown). As a result, the battery stack 16 and intermediate plate 18, which are bound to the pair of end plates 20 by the restraint bands 22, are fixed to the case 14. More specifically, the case 14 has a pair of walls 14a that are located outside the pair of end plates 20 with respect to the battery stack 16 and extend parallel to the vehicle front-to-rear direction (extension direction D2). The pair of end plates 20 may be fastened to the pair of walls 14a via fasteners. Alternatively, the pair of end plates 20 may be fastened to one of the walls of the case 14 located on both sides in the vehicle vertical direction (not shown in FIG. 1).

[0024] As described above, the battery pack 10 of this embodiment includes a battery stack 16 with an intermediate plate 18 interposed therebetween. Furthermore, as shown in FIG. 1 , the intermediate plate 18 is formed to be longer than each battery cell 12 in the extension direction D2 (vehicle front-rear direction). Furthermore, the intermediate plate 18 has the same length as the pair of end plates 20 in the extension direction D2. Note that the intermediate plate 18 does not necessarily have to have the exact same length as the pair of end plates 20, and may have substantially the same length as the pair of end plates 20.

[0025] Furthermore, the case 14 of the battery pack 10 includes a skeletal structural member 24 disposed between adjacent battery stacks 16. The skeletal structural member 24 extends along the stacking direction D1 (vehicle width direction) and connects the pair of wall portions 14a. In other words, the skeletal structural member 24 forms the framework of the case 14. The intermediate plate 18 and the pair of end plates 20 face the skeletal structural member 24 in the extension direction D2 (vehicle front-rear direction).

[0026] More specifically, as an example, the skeletal structural members 24 are disposed between three pairs (i.e., all) of adjacent battery stacks 16. Alternatively, the skeletal structural members 24 may be disposed between only one or two pairs of battery stacks 16. In the example shown in Fig. 1, a gap is provided between the intermediate plate 18 and the skeletal structural member 24 facing it.

[0027] 2.Effects Figure 2 is a diagram illustrating the effect of the structure of the battery pack 10 according to the embodiment. More specifically, Figure 2 illustrates only one battery stack 16 included in the battery pack 10 and two skeletal structural members 24 positioned around it. As shown in Figure 2(A), when an impact load is applied to the case 14 from one side in the extension direction D2 (the vehicle front-rear direction), the impact load acts to crush the case 14 in the extension direction D2, as shown in Figure 2(B).

[0028] As described above, the battery pack 10 of this embodiment includes a battery stack 16 with an intermediate plate 18 interposed therebetween. In the extension direction D2, the intermediate plate 18 is longer than each battery cell 12 and has the same length as the pair of end plates 20. Therefore, as shown in FIG. 2(B), when an impact load acts to crush the case 14 in the extension direction D2, the intermediate plate 18 and the pair of end plates 20 (via the restraint bands 22) come into contact with the case 14 (skeletal structural member 24) before the battery cells 12 do. The intermediate plate 18 and the pair of end plates 20 then generate a reaction force against the contact load.

[0029] As described above, the structure of the battery pack 10 of this embodiment allows an impact load received from the extension direction D2 to be received on a "surface" (i.e., by the intermediate plate 18 and the pair of end plates 20). This significantly reduces the direct input of the impact load to the battery cells 12. In other words, the impact load acting on the battery cells 12 can be effectively alleviated. This applies not only to the battery stack 16 shown in FIG. 2, but also to the remaining battery stacks 16 not shown.

[0030] Furthermore, in the battery pack 10 of this embodiment, the intermediate plate 18 is disposed approximately in the center of the multiple battery cells 12 (battery stack 16) in the stacking direction D1 (vehicle width direction). In this regard, the effect of mitigating impact loads acting on the battery cells 12 can be obtained even if the intermediate plate 18 is not necessarily disposed approximately in the center of the stacking direction D1. Therefore, the intermediate plate 18 may be disposed between any adjacent battery cells 12 included in the battery stack 16. Furthermore, by disposing the intermediate plate 18 approximately in the center of the stacking direction D1, it becomes possible for the intermediate plate 18 and the pair of end plates 20 to receive the impact load evenly. This enhances the effect of mitigating impact loads.

[0031] Furthermore, the battery pack 10 of this embodiment includes a skeletal structural member 24 that is disposed between adjacent battery stacks 16 and extends along the stacking direction D1 to form the skeleton of the case 14. This allows the skeletal structural member 24 to be utilized by the intermediate plate 18 and the pair of end plates 20 to bear the impact load across a "surface" when an impact load is applied from the above-mentioned extension direction D2.

[0032] In this embodiment, the extension direction D2 is parallel to the vehicle longitudinal direction, and therefore, the battery pack 10 has a battery pack structure that can effectively absorb impact loads acting on the battery pack 10 from the vehicle longitudinal direction.

[0033] 3. Variations The intermediate plate 18 according to the above-described embodiment may be joined to the case 14. More specifically, the intermediate plate 18 may be joined to, for example, one of the wall portions (not shown) of the case 14 located on both sides in the vertical direction of the vehicle. The joining here can be performed by any method, such as fastening or welding. Joining the intermediate plate 18 to the case 14 in this manner also has the effect of suppressing vibration of the case 14 while the vehicle is traveling.

[0034] 1, the battery pack 10 does not necessarily have to include a skeletal structural member 24. If the battery pack 10 does not include a skeletal structural member 24, for example, if the battery pack 10 includes a restraint band 22 as shown in FIG. 1, the restraint band 22 can be used to support an impact load on a "surface" between the intermediate plate 18 and the pair of end plates 20. Even if the battery pack 10 does not include a skeletal structural member 24 and does not include a restraint band in the position shown in FIG. 1, when an impact load is applied from the extension direction D2, the wall of the case 14 located at the end of the extension direction D2 can be used to support the impact load on a "surface" between the intermediate plate 18 and the pair of end plates 20.

[0035] Furthermore, the "intermediate plates" according to the present disclosure may be arranged, for example, as follows. Fig. 3 is a diagram illustrating an example of the arrangement of intermediate plates according to a modified embodiment. The battery pack 30 shown in Fig. 3 includes two intermediate plates 34 for each battery stack 32. As in this example, there may be multiple "intermediate plates" arranged for one battery stack, and they may be arranged between two or more pairs of adjacent battery cells.

[0036] 3, the two intermediate plates 34 are disposed at equal intervals between the multiple battery cells 12 in the stacking direction D1. This configuration makes it possible to use the multiple intermediate plates 34 together with the pair of end plates 20 to evenly absorb impact loads, further enhancing the impact load mitigation effect.

[0037] Additionally, in the "battery pack" according to the present disclosure, the "stacking direction" is not limited to the vehicle width direction, and therefore the "extension direction" is not limited to the vehicle front-rear direction. Also, the number of "battery stacks" included in the "battery pack" is generally multiple, but may be one.

[0038] However, the "battery pack" according to the present disclosure does not necessarily have to include a "pair of end plates." That is, the battery pack may have a CTP (cell-to-pack) structure in which the frame of the case is used as the end plates, without end plates. Even in a battery pack with such a CTP structure, by including an "intermediate plate," a structure can be obtained in which the intermediate plate absorbs impact loads from the extension direction before the multiple battery cells. In such a battery pack, the multiple battery cells (battery stack) may be bound together with the intermediate plate by, for example, a restraint band similar to the above-described restraint band 22, and attached to the case via the restraint band. [Explanation of symbols]

[0039] 10, 30 battery packs 12 battery cells 14 Battery pack case 16, 32 battery stack 18, 34 Intermediate plate 20 End Plate 22 Restraint Band 24 Skeletal structural members

Claims

1. a battery stack including a plurality of battery cells stacked in a first direction; a case for accommodating the battery stack; a pair of end plates joined to the case at both ends of the battery stack in the first direction; an intermediate plate that is joined to the case and disposed between at least one pair of adjacent battery cells included in the battery stack, and that protrudes beyond the battery cells in a second direction that is perpendicular to both the first direction and the vehicle vertical direction; Battery pack.

2. a length of the battery stack in the first direction is greater than a length of the intermediate plate in the second direction; The battery pack according to claim 1 .

3. Further comprising a restraining member connecting the pair of end plates. The battery pack according to claim 2 .

4. The restraining member is made of metal. The battery pack according to claim 3 .

5. A battery stack including a plurality of battery cells stacked in a first direction; a case that houses the battery stack and includes portions that are located on both ends of the battery stack in the first direction; an intermediate plate that is joined to the case and disposed between at least one pair of adjacent battery cells included in the battery stack, and that protrudes beyond the battery cells in a second direction that is perpendicular to both the first direction and the vehicle vertical direction; Battery pack.

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