Battery pack

Abstract

To increase the protection capability of a battery module.SOLUTION: A battery pack 100 includes a case 1, a battery module 2 having a bus bar 2b at a side part in a left-right direction, a member main body 41 extending in a front-back direction, and a battery fastening member 4 having a pair of fastening parts 4a for fixing the battery module 2 and the case 1 at both end parts of the member main body 41 in the front-back direction and disposed at a side part side of the battery module 2 in the left-right direction. The battery fastening member 4 has an upper end disposed over a lower end of the bus bar 2b and has at least a part thereof formed thin in an up-down direction. The thin part is disposed lower than the lower end of the bus bar 2b.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 modules stored inside or the bus bars provided on the side portions of the battery modules. 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 modules in order to achieve further safety.

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

Means for Solving the Problems

[0006] The battery pack according to the present disclosure includes a case, a battery module having bus bars on side surfaces in the left - right direction, a member body extending in the front - rear direction, and a pair of fastening portions for fixing the battery module and the case to both ends of the member body in the front - rear direction, and a battery fastening member disposed on the side surface side in the left - right direction. The battery fastening member has an upper end disposed above the lower end of the bus bar, and at least a part thereof is formed to be thin in the vertical direction, and the thinly formed portion is disposed at a position lower than the lower end of the bus bar. Thereby, when a load is applied to the battery pack, it is possible to suppress a load from being applied to the battery module due to the movement of the bus bar provided on the side portion of 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 shown 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 100 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 100 when mounted on a vehicle for explanation.

[0012] As shown in FIGS. 1 and 2, the battery pack 100 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 - transmitting member 6.

[0013] Hereinafter, the left - right direction of the battery pack 100 when mounted on this vehicle may be described as the side - part direction. Also, in both the front - rear direction and the left - right direction, the direction closer to the center of the battery pack 100 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 as the outer side.

[0014] The case 1 is a case that houses the 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 100 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. The case 1 has a bottom surface 1a. Note that the left - right direction ends of the outer shape of the case 1 are defined as the side parts 1b of the case 1.

[0015] More specifically, the left - right direction structural member 3, the battery fastening member 4, and the front - rear direction structural member 5 are each 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. Here, the battery module 2 is configured by stacking a plurality of battery cells in the vertical direction. The battery module 2 is arranged inside the front - rear direction between two adjacent left - right direction structural members 3 among the plurality of left - right direction structural members 3.

[0017] The battery module 2 has a connection part 2a that protrudes from the side part. Also, by fixing the connection part 2a to the case 1 via the fastening part 4a of the battery fastening member 4 described later, the battery module 2 is fixed to the case 1. Here, it is assumed that the connection part 2a is provided with a hole that penetrates in the vertical direction and can be bolted.

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

[0019] Furthermore, a bus bar 2b is arranged on the side part side where the connection part 2a is provided for the battery module 2. The bus bar 2b electrically connects a plurality of battery cells stacked in the vertical direction. In the front - rear direction of the right - hand side part of the battery module 2, the bus bar 2b is arranged so as to be sandwiched in the front - rear direction by the two connection parts 2a.

[0020] Hereinafter, in order to simplify the description of the configuration of the battery pack 100, the description will be made 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 - hand side part of the battery module 2.

[0021] As shown in FIG. 2, the left-right direction structural member 3 is an in-battery-pack 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-pack structural member and is arranged near the side surface 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 near the side portion 1b of the case 1, but here, it will be described as being provided only near the left and right side portions 1b of the case 1.

[0023] Here, the plurality of left-right direction structural members 3 are in a state where their ends are in contact with the front-rear direction structural member 5, are arranged orthogonally to the front-rear direction structural member 5, and extend in the left-right direction.

[0024] The battery fastening member 4 is arranged between the side portions in the left-right direction of the battery module 2 and the front-rear direction structural member 5. The battery fastening member 4 has, in the member main body 41, a plurality of fastening portions 42, 43 which are holes used for the purpose of fixing to the battery module 2 and through which bolts can penetrate in the vertical direction, and a plurality of conveyance holes 44, 45 used for the purpose of conveyance. Note that the conveyance holes 44, 45 are holes used when the battery fastening member 4 is picked up and conveyed by an automatic machine during the manufacture of the case 1.

[0025] More specifically, the member body 41 is a member that extends in the front-rear direction, has a predetermined width that is shorter in the left-right direction than in the front-rear direction, and is formed thinner in the up-down direction than in the left-right direction. The battery fastening member 4 has a pair of fastening portions 42 and 43 formed in the vicinity of both end portions in the front-rear direction, and a pair of conveying holes 44 and 45 formed inside the pair of fastening portions 42 and 43 in the front-rear direction. In the following, the fastening portion may be described as the first fastening portion 42 and the second fastening portion 43, and the conveying hole may be described as the first conveying hole 44 and the second conveying hole 45.

[0026] Typically, as shown in FIG. 2, the fastening portions 42 and 43 and the conveying holes 44 and 45 are arranged at positions that are substantially aligned in the left-right direction and are arranged continuously in the front-rear direction. That is, in the member body 41, starting from the front side, they are arranged in the order of the fastening portion 42, the conveying hole 44, the conveying hole 45, and the fastening portion 43. In FIG. 2, a state is shown in which, in the member body 41 of the battery fastening member 4, holes other than these are also formed in the vicinity of the fastening portions 42 and 43.

[0027] Here, at the positions where these fastening portions 42 and 43 and the conveying holes 44 and 45 are formed in the member body 41, a widened portion is formed so as to widen in the right direction, which is the side opposite to the battery module 2 side.

[0028] Here, in the member body 41, the portion where the first fastening portion 42 is provided and is widened is defined as the first widened portion 41a, the portion where the second fastening portion 43 is provided and is widened is defined as the second widened portion 41b, the portion where the first conveying hole 44 is provided and is widened is defined as the third widened portion 41c, and the portion where the second conveying hole 45 is provided and is widened is defined as the fourth widened portion 41d.

[0029] The first widened portion 41a and the second widened portion 41b are formed longer in the right direction than the third widened portion 41c and the fourth widened portion 41d.

[0030] As shown in FIG. 3 here, the fastening portions 42 and 43 are arranged closer to the outside in the front-rear direction. Specifically, the fastening portions 42 and 43 that connect to the connection portion 2a of the battery module 2 can be arranged near the end portions in the front-rear direction of the battery module 2 main body so as to be as close to the outside as possible within a range that does not extend outside the end portions in the front-rear direction of the battery module 2 main body.

[0031] As a result, as shown in FIG. 3, in a top view, an EA (energy absorption) space is set to be surrounded by the right end portion of the first wide portion 41a, the right end portion of the second wide portion 41b, and the position immediately before a line segment extending in the left-right direction in the side direction of the battery module 2 reaches the battery module 2, and the EA space can be ensured to be as wide as possible.

[0032] Furthermore, the member main body 41 is formed such that at least between the first wide portion 41a and the second wide portion 41b, the left end portion 4b in the left-right direction close to the side portion of the battery module 2 is thin in the height direction and passes through a low position. Here, FIG. 4 is a view showing a main part of the battery pack from a side view point, and FIG. 5 is a perspective view of the member main body 41 of the battery fastening member 4.

[0033] Specifically, as shown in FIG. 4, in the arrangement of the normal battery module 2 and the battery fastening member 4, the upper end of the member main body 41 of the battery fastening member 4 is arranged slightly above the lower end of the bus bar 2b provided on the battery module 2.

[0034] Here, as shown in FIG. 5, at the left end portion 4b on the battery module 2 side of the battery fastening member 4, at least a part is formed thin in the vertical direction, and the thin-formed portion is arranged at a position lower than the lower end of the bus bar 2b.

[0035] Here, at the bridging portion 41f between the first wide portion 41a and the second wide portion 41b, the left end portion 4b is formed thin in the vertical direction and is formed so as to pass only through a low position in the vertical direction. Then, when the battery module 2 and the battery fastening member 4 are arranged in the battery pack 100, the bridging portion 41f formed thin in the vertical direction is arranged below the lower end of the bus bar 2b when compared in the vertical direction.

[0036] The bridging portion 41f is defined as the portion between the inner end portion of the first wide portion 41a in the front-rear direction and the inner end portion of the second wide portion 41b.

[0037] Note that, as shown in FIG. 4, the left end portion 4b formed thin in the vertical direction in the battery fastening member 4 is not limited to the bridging portion 41f, and may be provided, for example, in a range other than the bridging portion 41f such as the entire left side on the battery module 2 side. That is, it is possible to provide the left end portion 4b having a thin shape in the vertical direction over the entire front-rear direction of the battery fastening member 4. Further, in the member main body 41 of the battery fastening member 4, the width in the left-right direction of the end portion 4b can be arbitrarily changed.

[0038] Furthermore, in the battery fastening member 4, the third wide portion 41c is arranged in front of the central portion in the front-rear direction of the battery fastening member 4, and the fourth wide portion 41d is arranged behind the central portion in the front-rear direction of the battery fastening member 4. That is, between the third wide portion 41c and the fourth wide portion 41d, a constricted portion 41e is formed in which a part of the right side is recessed toward the battery module 2 side so that the width in the left-right direction of the member main body 41 is narrowed.

[0039] In other words, the constricted portion 41e is a portion that is recessed toward the battery module 2 side and is formed short in the left-right direction between the wide portions 41c and 41d in which a pair of conveying holes 44 and 45 are formed in the front-rear direction and on the side opposite to the battery module 2 side in the left-right direction.

[0040] Next, the operation of protecting the battery module 2 when an external force is applied to the case 1 of the battery pack 100 having the above-described configuration will be described.

[0041] First, as shown in FIG. 3, since the fastening portions 42 and 43 are arranged closer to the outside in the front-rear direction, a wide EA space is secured. As a result, even when an object collides with the right side portion 1b of the battery pack 100 and a load is applied toward the inside of the battery pack 100, energy absorption can be completed before the load is applied to the battery module 2.

[0042] In addition, in order to secure such a wide EA space, since it is necessary to increase the distance in the front-rear direction between the connection portions 2a provided on the battery module 2, it is necessary to form the battery module 2 longer in the front-rear direction.

[0043] Therefore, in the battery module 2, considering maintaining the same battery capacity, the length in the left-right direction can be shortened according to the formation longer in the front-rear direction. Accordingly, the size of the battery pack 100 in the left-right direction can be reduced as the size of the battery module 2 in the left-right direction can be reduced.

[0044] Further, a constricted portion 41e is provided in the member main body 41 of the battery fastening member 4. By forming the central portion in the front-rear direction of the member main body 41 into a constricted shape in this way, when an external force is applied to the case 1 from the outside and a part of the front-rear direction structural member 5 is bent inward in the left-right direction, a wide EA space can be secured at the central portion in the front-rear direction that is most likely to approach the side surface of the battery module 2.

[0045] In addition, the bridging portion 41f of the battery fastening member 4 is arranged to be below the lower end of the bus bar 2b of the battery module 2 when the battery module 2 and the battery fastening member 4 are arranged in the battery pack 100.

[0046] Therefore, even when a load is applied from the side portion 1b on the right side of the case 1 and the battery fastening member 4 is pushed out to the left side, which is the side of the battery module 2, the bridging portion 41f is likely to enter below the lower end of the bus bar 2b.

[0047] As a result, the distance until the battery fastening member 4 presses the bus bar 2b can be increased. Therefore, in the battery pack 100, when an external force load is applied, damage to the bus bar 2b caused by the battery fastening member 4 pressing the bus bar 2b can be reduced.

[0048] Also, FIG. 6 is a top view of the battery pack 100, showing the locations where the left - right direction structural members 3 and the front - rear direction structural members 5 are arranged by thick solid lines, and the location where the battery fastening member 4 is arranged by thick dashed lines.

[0049] As shown in FIG. 6, for example, in the vicinity of the side portion 1b on the right side of the battery pack 100, a plurality of battery fastening members 4 are arranged in a straight line in the front - rear direction. Here, since the battery fastening member 4 has a shape extending in the front - rear direction, it can be considered that a group of a plurality of battery fastening members 4 and the front - rear direction structural member 5 are arranged in parallel at a predetermined distance from each other.

[0050] Here, the battery fastening member 4 can be fixed in a state of being connected to the left - right direction structural member 3 inside the front - rear direction structural member 5 in the left - right direction.

[0051] In this way, by fixing the battery fastening member 4 and the left - right direction structural member 3, in the vicinity of the side portion 1b of the case 1, both the battery fastening member 4 and the front - rear direction structural member 5 can be used as support members extending in the front - rear direction to support the case 1. Therefore, the rigidity of the battery pack 100 can be improved.

[0052] To summarize the above, when a load is applied from the side portion 1b of the case 1 with the battery fastening member 4 disposed on the side portion of the battery module 2, it is possible to gain the distance until the battery fastening member 4 moves and presses against the bus bar 2b. Also, even when the longitudinal direction structural member 5 bends inward in the lateral direction, it is possible to secure an EA space that absorbs energy until the bent longitudinal direction structural member 5 or the like presses against the battery module 2.

[0053] Further, the battery fastening member 4 can function as a frame of the case 1 by connecting with the lateral direction structural member 3, so that the rigidity of the battery pack 100 can be enhanced.

[0054] Therefore, in the battery pack 100, the protection ability of the stored battery module 2 can be enhanced.

[0055] Note that the present invention is not limited to the above-described embodiment, and can be appropriately modified without departing from the gist. 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 embodiment within the scope of the present invention.

Explanation of Reference Numerals

[0056] 100 Battery pack 1 Case 1a Bottom surface 1b Side portion 2 Battery module 2a Connection portion 2b Bus bar 3 Lateral direction structural member 4 Battery fastening member 4a Fastening portion 4b Left end portion 5 Longitudinal direction structural member 6 Load transmission member 41 Member body 41a First wide portion 41b Second wide portion 41c Third wide portion 41d Fourth wide part 41e Constriction part 41f Bridging part 42 First fastening part 43 Second fastening part 44 First conveying hole 45 Second conveying hole

Claims

1. A case, a battery module having bus bars on side portions in the left - right direction, a member body extending in the front - rear direction, having a pair of fastening portions for fixing the battery module and the case to both end portions of the member body in the front - rear direction, and a battery fastening member arranged on the side portion side in the left - right direction of the battery module, wherein the battery fastening member, has an upper end arranged above the lower end of the bus bar, and at least a part thereof is formed thin in the vertical direction, and the thin - formed portion is arranged at a position lower than the lower end of the bus bar, a battery pack.

2. The member body of the battery fastening member, has a pair of conveyance holes formed inside the pair of fastening portions in the front - rear direction, and a plurality of wide portions formed wide so as to spread to the side opposite to the battery module side at the locations where the pair of fastening portions and the pair of conveyance holes are formed, and has a constricted portion formed in a shape recessed toward the battery module side between the wide portions where the pair of conveyance holes are formed in the front - rear direction and on the side opposite to the battery module side in the left - right direction, The battery pack according to Claim 1.

3. The member body of the battery fastening member, has the wide portion where the pair of fastening portions are provided formed longer in the left - right direction than the wide portion where the conveyance holes are provided, The battery pack according to Claim 2.

4. The fastening portion, is arranged near the end portion of the battery module in the front - rear direction, The battery pack according to Claim 1 or Claim 2.

5. a front - rear direction structural member arranged near the side portion of the case and extending in the front - rear direction, and a plurality of left - right direction structural members having ends in contact with the front - rear direction structural member and arranged orthogonally to the front - rear direction structural member and extending in the left - right direction, wherein the battery fastening member, is connected and fixed to the left - right direction structural member inside the front - rear direction structural member in the left - right direction, The battery pack according to Claim 1 or Claim 2.

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