Structure for mounting battery pack on vehicle and manufacturing method therefor

Abstract

To provide a structure for mounting a battery pack on a vehicle that is able to prevent deterioration in the motion performance of the vehicle even when a common shock absorbing material is adopted, and to provide a manufacturing method therefor.SOLUTION: A structure for mounting a battery pack, including a battery stack, on a vehicle includes: a pair of impact absorbers extending in a vehicle frontward and rearward directions so as to sandwich an outer side of the battery pack in a vehicle width direction, and longer than the battery pack in the vehicle frontward and rearward directions; and a cross member extending in the vehicle width direction, both ends of the cross member being respectively connected to end parts of the impact absorbing members.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a vehicle mounting structure of a battery pack for mounting the battery pack on a vehicle and a manufacturing method thereof.

Background Art

[0002] A vehicle mounting structure of a battery pack including a pair of shock absorbers extending in the vehicle front-rear direction so as to sandwich the outside in the vehicle width direction of the battery pack is known (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, a shock absorber on the side of the battery pack is attached to a rocker of the underbody of the vehicle. In this way, the presence of the battery pack between the rockers improves the rigidity against the relative torsion in the roll direction of the rockers. That is, in the roll direction, the body and the battery pack are engaged and the rigidity is improved, so that the motion performance of the vehicle is improved.

[0005] On the other hand, for example, for battery packs with different battery capacities, it is assumed that a common shock absorber is adopted for the purpose of cost reduction. In that case, the length of the shock absorber in the vehicle front-rear direction is determined according to the largest battery pack. For this reason, the shock absorber may protrude in the vehicle front-rear direction more than the battery pack. As a result, the rigidity against the relative torsion in the roll direction is reduced, and there is a risk that the motion performance of the vehicle deteriorates.

[0006] The present disclosure has been made to solve such problems, and a main object thereof is to provide a vehicle-mounted structure of a battery pack and a method for manufacturing the same, which can suppress deterioration of the driving performance of a vehicle even when a common shock absorber is employed.

Means for Solving the Problems

[0007] One aspect of the present disclosure for achieving the above object is a vehicle-mounted structure of a battery pack including a battery stack, a pair of shock absorbers that extend in the longitudinal direction of the vehicle so as to sandwich the outside in the vehicle width direction of the battery pack and are longer than the battery pack in the longitudinal direction of the vehicle, and a cross member that extends in the vehicle width direction and both ends of which are respectively connected to the ends of the respective shock absorbers, The vehicle-mounted structure of the battery pack is provided with is. In this aspect, The cross-sectional shape of both ends of the cross member is a U shape that opens to the outside in the vehicle width direction, and the ends of the respective shock absorbers may be respectively fitted into the openings at both ends of the cross member. In this aspect, The ends of the respective shock absorbers and both ends of the cross member may be fastened by a fastening member that is longer than the vertical length of the cross member by a predetermined value or more and penetrates in the vertical direction. One aspect of the present disclosure for achieving the above object is A method for manufacturing a vehicle-mounted structure of a battery pack including a battery stack, A pair of shock absorbers that are longer than the battery pack in the longitudinal direction of the vehicle are arranged in the longitudinal direction of the vehicle so as to sandwich the outside in the vehicle width direction of the battery pack, Both ends of a cross member that extends in the vehicle width direction are respectively connected to the ends of the respective shock absorbers, A method for manufacturing a vehicle-mounted structure of a battery pack is.

Effects of the Invention

[0008] According to the present disclosure, even when a common shock absorber is employed, it is possible to provide a vehicle mounting structure of a battery pack and a manufacturing method thereof that can suppress deterioration of the vehicle's motion performance.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0010] Hereinafter, the present embodiment will be described with reference to the drawings. FIG. 1 is a top view of the vehicle mounting structure of the battery pack according to the present embodiment as viewed from above. The vehicle mounting structure 1 of the battery pack according to the present embodiment includes a battery pack 2, a pair of shock absorbers 3, and a cross member 4.

[0011] The battery pack 2 is mounted on vehicles such as hybrid vehicles, plug-in hybrid vehicles, fuel cell vehicles, and electric vehicles, for example. The vehicle mounting structure 1 of the battery pack 2 is provided, for example, below the floor panel and inside the skeletal members of the vehicle.

[0012] The battery pack 2 accommodates, for example, a battery stack in which a plurality of battery cells are stacked in a case. The battery cells are composed of lithium ion batteries or the like.

[0013] The pair of shock absorbers (EA material: Energy Absorption) 3 are members for absorbing shocks from the side of the vehicle. The pair of shock absorbers 3 are provided inside the rocker of the underbody.

[0014] A pair of shock absorbers 3 extend in the vehicle front-rear direction so as to sandwich the outside in the vehicle width direction of the battery pack 2. Thereby, for example, as shown in FIG. 2, at the time of a side collision of the vehicle or the like, the side of the battery pack 2, particularly, a portion without a battery skeleton or a vehicle body skeleton can be appropriately protected.

[0015] The pair of shock absorbers 3 are longer than the battery pack 2 in the vehicle front-rear direction. It is assumed that a common shock absorber 3 is adopted for battery packs 2 with different battery capacities for the purpose of cost reduction and improvement of mounting expandability. In that case, the length of the shock absorber 3 in the vehicle front-rear direction is determined according to the largest battery pack 2. For this reason, the shock absorber 3 is longer than the battery pack 2 in the vehicle front-rear direction as described above, and the shock absorber 3 may protrude from the battery pack 2 in the vehicle front-rear direction.

[0016] By the way, as described above, when the shock absorber protrudes from the battery pack in the vehicle front-rear direction, the rigidity against relative torsion in the roll direction of the vehicle decreases, and there is a possibility that the motion performance of the vehicle deteriorates.

[0017] On the other hand, the vehicle mounting structure 1 of the battery pack 2 according to the present embodiment includes a cross member 4 that extends in the vehicle width direction and both ends of which are respectively connected to the ends of the shock absorbers 3 as shown in FIG. 1. By this cross member 4, the rigidity against relative torsion in the roll direction of the vehicle is improved, and deterioration of the motion performance of the vehicle can be suppressed.

[0018] FIG. 3 is a cross-sectional view when the cross member 4 is cut in the vertical direction along line A-A shown in FIG. 1. The cross member 4 is composed of, for example, a metal member having a sectional second moment that can withstand a side impact load of 300 kN. The cross member 4 is composed of, for example, a 1180 material (high-tensile steel sheet) of iron with a plate thickness of 2 mm or more. Thereby, it can withstand the relative torsion in the roll direction of the vehicle described above.

[0019] The cross member 4 is composed of a hollow brace member 41 extending in the vehicle width direction and a pair of patch members 42 respectively connected to both ends of the brace member 41. Both ends of the brace member 41 and the pair of patch members 42 are connected by welding or the like, but are not limited thereto. The brace member 41 and the pair of patch members 42 may be integrally formed.

[0020] The cross section of the brace member 41 is formed in a square shape. The cross-sectional shapes of the patch members 42 at both ends of the brace member 41 are formed in a U shape opening to the outside in the vehicle width direction as shown in FIG. 3. The rear ends of the respective shock absorbers 3 are respectively fitted into the openings of the patch members 42. Thereby, the manufacturing intersection in the vehicle width direction of the cross member 4 can be absorbed.

[0021] For example, bolts 5 penetrate vertically through the rear ends of the respective shock absorbers 3 and the patch members 42 of the cross member 4. By tightening nuts 7 through washers 6 on the penetrating bolts 5, the rear ends of the respective shock absorbers 3 and the patch members 42 of the cross member 4 are fastened by the bolts 5 and nuts which are fastening members.

[0022] Here, for example, it is assumed that the shock absorber 3 is made of aluminum and the case of the battery pack 2 and the cross member 4 are made of iron. In this case, due to the difference in the linear expansion coefficients between the shock absorber 3 and the case of the battery pack 2 and the cross member 4, displacement occurs between the two members, so it is necessary to absorb this displacement.

[0023] For example, when bolts are arranged in the horizontal direction, displacement due to the above linear expansion coefficient of about 1 mm occurs at a horizontal length of 1 m. Therefore, a structure for absorbing the displacement due to the above linear expansion coefficient is required.

[0024] In contrast, in the present embodiment, the length of the bolt 5 is longer than the vertical length of the cross member 4 by a predetermined value or more. As a result, while deforming the bolt 5, the displacement due to the coefficient of linear expansion can be absorbed by the length of the bolt 5 that is greater than or equal to the predetermined value. The predetermined value is, for example, about 1 to 2 mm, and is a length capable of absorbing the above-described displacement.

[0025] Subsequently, the vehicle mounting structure 1 of the battery pack 2 and its manufacturing method will be described. First, a pair of shock absorbing members 3 that are longer in the vehicle front-rear direction than the battery pack 2 are arranged in the vehicle front-rear direction so as to sandwich the outside in the vehicle width direction of the battery pack 2. Both ends of the cross member 4 extending in the vehicle width direction are respectively connected to the rear end portions of the respective shock absorbing members 3. Note that the battery pack 2 may be arranged between the pair of shock absorbing members 3 after connecting the cross member 4 and each shock absorbing member 3.

[0026] Although some embodiments of the present disclosure have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalent scope thereof.

Explanation of Reference Numerals

[0027] 1 Vehicle mounting structure, 2 Battery pack, 3 Shock absorbing member, 4 Cross member, 5 Bolt, 6 Washer, 7 Nut, 41 Brace member, 42 Patch member

Claims

1. A vehicle-mounted structure of a battery pack including a battery stack, a pair of shock absorbers that extend in the vehicle longitudinal direction so as to sandwich the outside in the vehicle width direction of the battery pack and are longer than the battery pack in the vehicle longitudinal direction, and a cross member that extends in the vehicle width direction and both ends of which are respectively connected to the ends of the respective shock absorbers, The vehicle-mounted structure of the battery pack comprising the above.

2. The vehicle-mounted structure of the battery pack according to Claim 1, wherein the cross-sectional shapes of both ends of the cross member are U-shaped openings on the outside in the vehicle width direction, and the ends of the respective shock absorbers are respectively fitted into the openings at both ends of the cross member, The vehicle-mounted structure of the battery pack.

3. The vehicle-mounted structure of the battery pack according to Claim 2, wherein the ends of the respective shock absorbers and both ends of the cross member are fastened by a fastening member that is longer than the vertical length of the cross member by a predetermined value or more and penetrates in the vertical direction, The vehicle-mounted structure of the battery pack.

4. A method for manufacturing a vehicle-mounted structure of a battery pack including a battery stack, wherein a pair of shock absorbers that are longer than the battery pack in the vehicle longitudinal direction are arranged in the vehicle longitudinal direction so as to sandwich the outside in the vehicle width direction of the battery pack, and both ends of a cross member that extends in the vehicle width direction are respectively connected to the ends of the respective shock absorbers, The method for manufacturing the vehicle-mounted structure of the battery pack.

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