Battery pack

Abstract

To increase the protection capability of a battery module.SOLUTION: A battery pack 10 includes a battery fastening member 4 including a fastening part 4a that fixes a battery module 2 having a connection part 2a to a case 1 using the connection part 2a, a front-back direction structure member 5 that is disposed near a side part of the case 1 and extends in a front-back direction, a plurality of left-right direction structure members 3 having an end part in contact with the front-back direction structure member 5, disposed orthogonal to the front-back direction structure member, and extending in the left-right direction, and a load transmission member 6 disposed near at least one side part of the case 1 and fixed linking the front-back direction structure member 5 and the left-right direction structure member 3. The battery module 2 is disposed inside in the front-back direction corresponding to a space between the two adjacent left-right direction structure members 3 among the plurality of left-right direction structure members 3. When fixed to the case 1 by the connection part 2a and the fastening part 4a, at least a part of the end part of the load transmission member 6 on the front-back direction structure member 5 side is disposed on the inside in the front-back direction compared to the fastening part 4a.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a battery pack.

Background Art

[0002] In recent years, battery packs have been used in electric vehicles and the like. Since it is conceivable that an external impact may be applied to the battery pack, a shock absorber is used. Patent Document 1 discloses an external shock absorber that can be manufactured at low cost and can protect the battery pack from shocks.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When an impact is applied to the battery pack from the outside due to a vehicle collision or the like, particularly when a load is applied to the side surface of the battery pack, a load may be applied to the battery module stored inside. Therefore, even when an impact is applied from the outside of the vehicle, there is a desire to enhance the protection ability of the stored battery module in order to ensure further safety.

[0005] The present disclosure has been made in view of the above-described problems, and provides a battery pack with enhanced protection ability for the stored battery module.

Means for Solving the Problems

[0006] The battery pack according to the present disclosure includes a battery fastening member having a fastening portion for fixing a battery module having a connection portion to a case using the connection portion, a longitudinal structure member disposed near a side portion of the case and extending in the front-rear direction, a plurality of lateral structure members whose ends abut against the longitudinal structure member and are arranged orthogonal to the longitudinal structure member and extend in the lateral direction, and a load transmission member disposed near at least one side portion of the case and fixed across the longitudinal structure member and the lateral structure members. The battery module is disposed inside in the front-rear direction between two adjacent lateral structure members among the plurality of lateral structure members, and when fixed to the case by the connection portion and the fastening portion, at least a part of the end portion of the load transmission member on the longitudinal structure member side is disposed more inside in the front-rear direction than the fastening portion. Thereby, when a load is applied to the battery pack, the load can be induced via the load transmission member so that a large load is not applied to the battery module.

Effects of the Invention

[0007] According to the present disclosure, it is possible to provide a battery pack with enhanced protection ability for the stored battery module.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0009] Embodiment 1 Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments. Also, for clarity of explanation, the following description and drawings are simplified as appropriate.

[0010] Hereinafter, the battery pack according to this embodiment will be described with reference to the drawings. FIG. 1 is a top view of the battery pack according to the present disclosure. FIG. 2 is an enlarged top view of the main part of the battery pack surrounded by a dashed-dotted line in FIG. 1.

[0011] Here, the left direction in FIGS. 1 and 2 is defined as the front direction (Fr direction) of the battery pack 10 when mounted on a vehicle, and the upward direction in FIGS. 1 and 2 is defined as the right direction (RH direction) of the battery pack 10 when mounted on a vehicle for explanation.

[0012] As shown in FIGS. 1 and 2, the battery pack 10 includes a case 1, a battery module 2, a plurality of left-right direction structural members 3, a battery fastening member 4, a front-rear direction structural member 5, and a load transmission member 6.

[0013] Hereinafter, the left-right direction of the battery pack 10 when mounted on this vehicle may be described as the side portion direction. Also, in both the front-rear direction and the left-right direction, the direction closer to the center of the battery pack 10 is defined as the inner side, and the opposite direction is defined as the outer side. For example, the direction in which the battery module 2 is provided inside the case 1 is defined as the inner side in the front-rear direction. Conversely, the outer side in the front-rear direction where the left-right direction structural members 3 arranged continuously in the front-rear direction are provided so as to sandwich the battery module 2 is defined.

[0014] Case 1 is a case that houses a battery module 2, a plurality of left - right direction structural members 3, a battery fastening member 4, and a front - rear direction structural member 5. The battery pack 10 includes a plurality of battery modules 2, left - right direction structural members 3, battery fastening members 4, front - rear direction structural members 5, and load - transmitting members 6. Case 1 has a bottom surface 1a (see FIG. 3). In addition, the left - right direction ends in the outer shape of case 1 may be described as the side portions of case 1. The side portion of the case is referred to as side portion 1b.

[0015] More specifically, the left - right direction structural member 3, the battery fastening member 4, and the front - rear direction structural member 5 are respectively provided on the bottom surface 1a. The battery module 2 is, for example, a lithium - ion battery or the like.

[0016] The battery module 2 is rectangular and extends in the front - rear direction and the left - right direction. The battery module 2 is arranged inside the case 1 in the front - rear direction inside between two adjacent left - right direction structural members 3 among the plurality of left - right direction structural members 3.

[0017] In addition, the battery module 2 has a connection portion 2a that protrudes from the side portion in the left - right direction. Also, the connection portion 2a is fixed to the case 1 via a fastening portion 4a of the battery fastening member 4 described later, so that the battery module 2 is fixed to the case 1. Here, it is assumed that the connection portion 2a is provided with a hole that penetrates in the up - down direction and can be bolted.

[0018] Here, for the battery module 2, two connection portions 2a that protrude rightward from the right - hand side portion are respectively provided on the front side and the rear side, and the same applies to the left - hand side portion. That is, the connection portion 2a of the battery module 2 is formed to protrude from each corner of the rectangular battery module 2 toward the side portion 1b of the adjacent case 1.

[0019] In addition, bus bars for electrically connecting the battery cells forming the battery module 2 are arranged on the left - right direction side portions of the battery module 2.

[0020] Hereinafter, in order to simplify the description of the configuration of the battery pack 10, the description will be made by focusing on the vicinity of the right side of this battery module 2, but the same configuration can be applied to the vicinity of the left side portion of the battery module 2.

[0021] As shown in FIG. 2, the left-right direction structural member 3 is an in-battery structural member (inner cross), which has a predetermined height upward from the bottom surface 1a and is provided in a shape extending in the left-right direction. Further, a plurality of left-right direction structural members 3 are continuously arranged at substantially equal intervals in the front-rear direction and separated from each other by a predetermined distance.

[0022] The front-rear direction structural member 5 is an in-battery structural member, which is arranged in the vicinity of the side portion 1b of the case 1. Further, the front-rear direction structural member 5 has a predetermined height upward from the bottom surface 1a and is provided in a shape extending in the front-rear direction. Note that the front-rear direction structural member 5 may be further provided at locations other than the vicinity of the side portion 1b of the case 1, but here, it will be described as being provided only in the vicinity of the left and right side portions 1b of the case 1.

[0023] Here, the end portions of the plurality of left-right direction structural members 3 are in contact with the front-rear direction structural member 5, and the extending direction with respect to the front-rear direction structural member 5 is the orthogonal direction, that is, they are arranged to extend in the left-right direction.

[0024] The battery fastening member 4 is arranged between the side portions of the battery module 2 in the left-right direction and the front-rear direction structural member 5. The battery fastening member 4 is provided with a plurality of fastening portions 4a which are holes through which bolts can penetrate in the vertical direction. Also, regarding the vertical position of the battery fastening member 4, typically, a part of the battery fastening member 4 is sandwiched between the load transmission member 6 and the connection portion 2a, the load transmission member 6 is arranged below the battery fastening member 4, and the connection portion 2a of the battery module 2 is arranged above the battery fastening member 4.

[0025] For example, the battery module 2 and the battery fastening member 4 are arranged such that the positions of the holes provided in the connection portion 2a and the holes provided in the fastening portion 4a are aligned in a straight line in the vertical direction. The battery module 2 and the battery fastening member 4 can be fixed to each other by bolt tightening using these holes.

[0026] The load transmission member 6 is fixed across the left - right direction structural member 3 and the front - rear direction structural member 5. Therefore, the load transmission member 6 is provided near the side portion 1b of the case 1.

[0027] Specifically, the load transmission member 6 is arranged so as to cover a part of each of the left - right direction structural member 3 and the front - rear direction structural member 5.

[0028] Also, the load transmission member 6 has a shape extending in the front - rear direction at the location where it covers the front - rear direction structural member 5. Specifically, at least a part of the end portion of the load transmission member 6 on the side of the front - rear direction structural member 5 is formed to be long in the front - rear direction from the extension of the left - right direction structural member 3 in the top view toward the battery module 2 side in the front - rear direction.

[0029] The load transmission member 6 is formed to be long in the front - rear direction at the location where it covers the front - rear direction structural member 5. That is, at least a part of the portion extending in the front - rear direction at the end portion near the side portion of the load transmission member 6 in the left - right direction is arranged on the inner side in the front - rear direction compared to the fastening portion 4a of the battery fastening member 4.

[0030] Therefore, at least a part of the end portion of the load transmission member 6 on the side of the front - rear direction structural member 5 is arranged on the inner side in the front - rear direction from this connection portion 2a through the space between the side portion 1b of the case 1 and the connection portion 2a arranged closest to the load transmission member 6.

[0031] The load transmission member 6 can be shaped to extend only forward or only backward at the end on the side of the front-rear direction structural member 5. In this case, for the location where one left-right direction structural member 3 abuts against the front-rear direction structural member 5, one member with the end on the side of the front-rear direction structural member 5 extending forward and one member with the end extending backward can be arranged respectively.

[0032] On the other hand, the load transmission member 6 can also be a single member whose end on the side of the front-rear direction structural member 5 extends in both the front and rear directions.

[0033] For example, on one side part of a battery module 2 in the left-right direction, at least two connection parts 2a are provided in alignment in the front-rear direction, and the fastening parts 4a of the corresponding battery fastening member 4 are arranged. Here, for the sake of explanation, among the plurality of fastening parts 4a for fixing the battery module 2 close to the front side of the load transmission member 6, the fastening part 4a provided on the front side is the fastening part 41 (not shown), and the fastening part 4a provided on the rear side is the fastening part 42. Similarly, among the plurality of fastening parts 4a for fixing the battery module 2 close to the rear side of the load transmission member 6, the fastening part 4a provided on the front side is the fastening part 43, and the fastening part 4a provided on the rear side is the fastening part 44.

[0034] When the end of the load transmission member 6 on the side of the front-rear direction structural member 5 has a shape extending forward, at least a part of the portion extending forward is arranged on the front side of the fastening part 42 provided at the rearmost among the fastening parts 4a arranged corresponding to the connection part 2a of the battery module 2 arranged close to the front side of the load transmission member 6. Similarly, when the end of the load transmission member 6 on the side of the front-rear direction structural member 5 has a shape extending backward, at least a part of the portion extending backward is arranged on the rear side of the fastening part 43 provided at the foremost among the fastening parts 4a arranged corresponding to the connection part 2a of the battery module 2 arranged close to the rear side of the load transmission member 6.

[0035] Also, for the sake of explanation here, regarding the load transmission member 6, the load transmission member 6 having a shape extending forward is defined as the load transmission member 61, and the load transmission member 6 having a shape extending rearward is defined as the load transmission member 62.

[0036] FIG. 3 is a top view showing a main part of the battery pack, which shows the relationship between the load transmission member 6 and the length of its arrangement. As shown in FIG. 3, a plurality of load transmission members 6 are provided corresponding to a plurality of left - right direction structural members 3. There are respectively provided a load transmission member (first load transmission member) 61 extending forward and a load transmission member (second load transmission member) 62 having a shape extending rearward. In adjacent left - right direction structural members 3, the distance from the rear end of the second load transmission member 62 arranged corresponding to the front left - right direction structural member 3 to the front end of the first load transmission member 61 arranged corresponding to the rear left - right direction structural member 3 is shorter than the sum of the distance from the front end to the rear end of the load transmission member 61 and the distance from the front end to the rear end of the load transmission member 62.

[0037] More specifically, as shown in FIG. 3, in the battery pack 10, the shape of the first load transmission member 61 and the second load transmission member 62 can be determined such that the distance A at the location where the load transmission members are separated from each other is shorter than the length obtained by adding the length B of one first load transmission member 61 and the length C of one second load transmission member 62.

[0038] Note that the length of the load transmission member 6 extending in the left - right direction, that is, the length of the portion where the load transmission member 6 covers the left - right direction structural member 3 can be arbitrarily changed. Typically, the inner ends in the left - right direction of the load transmission member 6 covering the left - right direction structural member 3 can be made inner in the left - right direction than the connection portion 2a of the battery module 2.

[0039] Further, when the load transmission member 6 fixes the fastening portion 4a of the battery fastening member 4 and the connection portion 2a of the battery module 2 using bolts, it can be fixed by the bolts passing through the holes provided in the load transmission member 6. Note that the method of fixing the load transmission member 6 is not limited to the method of forming holes and passing bolts through the holes. For example, the load transmission member 6 may be fixed by the battery fastening member 4 pressing downward from above at a position different from the fastening portion 4a and the connection portion 2a when fixing the fastening portion 4a and the connection portion 2a with bolts without any holes provided.

[0040] FIG. 4 is an enlarged perspective view of a main part of the battery pack shown in FIG. 1. Further, FIG. 5 is an enlarged perspective view of a main part of the battery pack in the same manner as FIG. 4, showing an example of a load path for dispersing the load by arrows. In FIGS. 4 and 5, the illustration of the battery module 2 is omitted. Here, a notch portion 6a is formed in the load transmission member 6 near a corner portion of the battery module 2 and in a location close to the battery fastening member 4.

[0041] Since the notch portion 6a is provided in the load transmission member 6, it is possible to prevent the three members, i.e., the left - right direction structural member 3, the battery fastening member 4, and the load transmission member 6, from being joined together. That is, by providing the notch portion 6a at least partially in the load transmission member 6, a location is formed to avoid contact between the load transmission member 6 and the battery fastening member 4. As a result, the left - right direction structural member 3 and the battery fastening member 4 can be in a state of directly abutting at a position away from the connection portion 2a and the fastening portion 4a.

[0042] With such a configuration, when a load is applied from the side portion of the battery pack 10, in the battery pack 10, as shown in FIG. 5, the load path is cut off. That is, when the load is transmitted from the load transmission member 6 to the battery module 2, it follows the path of the dotted arrow in FIG. 5. In this path, it becomes difficult for the force to be transmitted from the load transmission member 6 to the battery module 2, so that the input of the load to the battery module 2 can be suppressed.

[0043] Also, when an external force is applied to the side portion 1b of Case 1, an example of the relationship between the position where the external force is applied and the way the load is transmitted into the battery pack 10 will be described with reference to the drawings. FIGS. 6(a) and 6(b) are top views showing an enlarged main part of the battery pack 10, and are diagrams respectively showing examples of load transmission when a force is applied from the outside due to a vehicle collision or the like by arrows.

[0044] FIG. 6(a) shows an example where a pole collides with a position on the extension of the left - right direction structural member 3, and a load is generated from the right side of one left - right direction structural member 3 toward the inside in the left - right direction. In this case, in the battery pack 10, a load is applied to the left - right direction structural member 3 from the position where the pole collided, in a state of being applied toward the inside in the left - right direction. Therefore, in the battery pack 10, it is difficult for the battery module 2 and the battery fastening member 4 to be loaded.

[0045] On the other hand, FIG. 6(b) shows an example where a load is generated toward the inside in the left - right direction at the middle of the left - right direction structural members 3 that are continuous in the front - rear direction, that is, at the position on the right side of the battery module 2. In this case, in the battery pack 10, from the position where the pole collided, the load flows to the load transmission member 6 side, and the load is dispersed to each of the two left - right direction structural members 3 arranged so as to sandwich the position collided in the front - rear direction. Therefore, in the battery pack 10, it is possible to suppress a large load from being applied to the battery module 2 and the battery fastening member 4.

[0046] Here, the first load transmission member 61 has a shape in which the end portion on the side portion side in the left - right direction extends forward, and the second load transmission member 62 has a shape in which it extends backward, and the end portions of each are set to the inside in the front - rear direction from the fastening portion 4a of the battery fastening member 4. In this case, regarding the bending starting point of the front - rear direction structural member 5, compared with the case where the load transmission members 61 and 62 whose parts are arranged inside in the front - rear direction from the fastening portion 4a are not provided, by providing these, the distance between the portions serving as the bending starting points of the front - rear direction structural member 5 is likely to be in a state of approaching.

[0047] Therefore, by providing the load transmission members 61 and 62 inside the battery pack 10, even when the longitudinal direction structural member 5 bends due to an external collision, the battery fastening member 4 is less likely to be pushed inward in the lateral direction by the longitudinal direction structural member 5.

[0048] Furthermore, in this case, it is possible to suppress the battery fastening member 4 pressed by the longitudinal direction structural member 5 from pressing the bus bar arranged on the side portion of the battery module 2 inward in the lateral direction.

[0049] Also, as shown in FIG. 3, by making the longitudinal lengths of the first load transmission member 61 and the second load transmission member 62 sufficiently long, when a load is applied, the distance between the collision location when an obstacle hits the outside of the battery pack 10 and the location acting as the bending starting point in the longitudinal direction structural member 5 can be made close.

[0050] That is, in the longitudinal direction structural member 5, since the distance between the force point and the moment acting point becomes short, the bending rigidity can be improved.

[0051] Furthermore, as shown in FIGS. 4 and 5, since the load transmission member 6 is provided with the notch portion 6a, the left and right direction structural member 3, the battery fastening member 4, and the load transmission member 6 can be in a state where they are not joined together in three layers, that is, a state where the load path is cut off. Therefore, even when a load is applied from the outside of the vehicle, the input to the fastening portion 4a can be suppressed.

[0052] As described above, in the battery pack 10, by arranging the load transmission members 6 having a shape extending in the longitudinal direction in the vicinity of the side portion of the battery pack 10 corresponding to the respective left and right direction structural members 3, the protection performance for the battery module 2 against an external load can be improved.

[0053] Note that the present invention is not limited to the above-described embodiments, and can be appropriately modified without departing from the gist thereof. That is, the above description has been appropriately omitted and simplified for the sake of clarity of explanation, and those skilled in the art can easily change, add, and convert each element of the embodiments within the scope of the present invention.

Explanation of Reference Numerals

[0054] 10 Battery pack 1 Case 1a Bottom surface 1b Side portion 2 Battery module 2a Connection portion 3 Left - right direction structural member 4 Battery fastening member 4a Fastening portion 5 Front - rear direction structural member 6 Load - transmitting member 61 First load - transmitting member 62 Second load - transmitting member 6a Notch portion 41 First fastening portion 42 Second fastening portion 43 Third fastening portion 44 Fourth fastening portion

Claims

1. A battery fastening member having a fastening portion for fixing a battery module having a connection portion to a case using the connection portion, A longitudinal structure member disposed near a side portion of the case and extending in the front-rear direction, A plurality of lateral structure members whose ends abut against the longitudinal structure member and are arranged orthogonally to the longitudinal structure member and extend in the lateral direction, A load transmission member disposed near at least one side portion of the case and fixed across the longitudinal structure member and the lateral structure members, When the battery module is disposed inside in the front-rear direction between two adjacent lateral structure members among the plurality of lateral structure members and is fixed to the case by the connection portion and the fastening portion, At least a part of an end portion of the load transmission member on the longitudinal structure member side is disposed more inward in the front-rear direction than the fastening portion, A battery pack.

2. The battery module is rectangular and extends in the front-rear direction and the lateral direction, In the case, the connection portion of the battery module is formed to protrude from each corner portion of the rectangular battery module toward the side portion of the adjacent case, The load transmission member, At least a part of an end portion of the load transmission member on the longitudinal structure member side is disposed more inward in the front-rear direction than the connection portion through between the side portion of the case and the connection portion disposed closest to the load transmission member, The battery pack according to claim 1.

3. The load transmission member, The end portion of the load transmission member on the longitudinal structure member side has a shape extending in at least one of the front-rear directions, When the end portion of the load transmission member on the longitudinal structure member side has a shape extending forward, at least a part of the portion extending forward is disposed on the front side of the fastening portion provided most rearward among the fastening portions arranged corresponding to the connection portion of the battery module disposed close to the front side of the load transmission member, When the end portion of the load transmission member on the longitudinal structure member side has a shape extending rearward, at least a part of the portion extending rearward is disposed on the rear side of the fastening portion provided most forward among the fastening portions arranged corresponding to the connection portion of the battery module disposed close to the rear side of the load transmission member, The battery pack according to claim 1 or claim 2.

4. The load transmission member, A first load transmission member having a portion extending forward, a second load transmission member having a portion extending rearward the first load transmission member and the second load transmission member are respectively provided corresponding to a plurality of the left-right direction structural members in the adjacent left-right direction structural members, the distance from the rear end portion of the second load transmission member arranged corresponding to the front left-right direction structural member to the front end portion of the first load transmission member arranged corresponding to the rear left-right direction structural member is shorter than the length obtained by adding the distance from the front end portion to the rear end portion of the first load transmission member and the distance from the front end portion to the rear end portion of the second load transmission member The battery pack according to claim 1 or claim 2

5. the load transmission member has a notch for avoiding contact with the battery fastening member The battery pack according to claim 1 or claim 2

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