Vehicle mounting structure for battery pack and manufacturing method thereof

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 the rocker of the underbody of the vehicle. Thus, 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 from the battery pack. As a result, the rigidity against the relative torsion in the roll direction may decrease, and the motion performance of the vehicle may deteriorate.

[0006] This disclosure was made to solve these problems, and its main purpose is to provide a vehicle mounting structure for a battery pack and a method for manufacturing the same that can suppress deterioration of the vehicle's dynamic performance even when a common shock-absorbing material is used. [Means for solving the problem]

[0007] One aspect of this disclosure for achieving the above objectives is: A vehicle mounting structure for a battery pack including a battery stack, A pair of shock-absorbing materials are provided, which extend in the vehicle longitudinal direction, sandwiching the outer side of the battery pack in the vehicle width direction, and which are longer in the vehicle longitudinal direction than the battery pack, A cross member extending in the vehicle width direction, with both ends connected to the ends of each of the impact absorbing materials, A vehicle mounting structure for a battery pack, equipped with the above. That is the case. On this flight, The cross-sectional shape of both ends of the cross member is a U-shape that opens outward in the vehicle width direction, and the ends of each shock-absorbing material may be fitted into the openings at both ends of the cross member. On this flight, The ends of each of the shock-absorbing materials and both ends of the cross member may be fastened together by fastening members that are longer than a predetermined value or more than the vertical length of the cross member, passing through in the vertical direction. One aspect of this disclosure for achieving the above objectives is: A method for manufacturing a vehicle mounting structure for a battery pack including a battery stack, A pair of shock-absorbing materials, longer in the vehicle's longitudinal direction than the aforementioned battery pack, are positioned in the vehicle's longitudinal direction so as to sandwich the outer side of the battery pack in the vehicle's width direction. Both ends of the cross member extending in the vehicle width direction are connected to the ends of each of the aforementioned impact absorbing materials, Manufacturing method for vehicle mounting structure of battery pack That is the case. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide a vehicle mounting structure for a battery pack and a method for manufacturing the same that can suppress deterioration of the vehicle's dynamic performance even when a common shock-absorbing material is used. [Brief explanation of the drawing]

[0009] [Figure 1] This is a top view of the vehicle mounting structure of the battery pack according to this embodiment, viewed from above. [Figure 2] This diagram shows the condition of the impact-absorbing material and battery pack during a side collision of a vehicle. [Figure 3] This is a cross-sectional view of the cross member when it is cut vertically along line AA shown in Figure 1. [Modes for carrying out the invention]

[0010] This embodiment will be described below with reference to the drawings. Figure 1 is a top view of the vehicle mounting structure of the battery pack according to this embodiment, viewed from above. The vehicle mounting structure 1 of the battery pack according to this embodiment comprises a battery pack 2, a pair of shock-absorbing materials 3, and a cross member 4.

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

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

[0013] The pair of impact-absorbing materials (EA material: Energy Absorption) 3 are components designed to absorb impacts from the side of the vehicle. The pair of impact-absorbing materials 3 are installed inside the rocker of the underbody.

[0014] The 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 risk 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 each shock absorber 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 vertically along the 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 consists of a hollow brace member 41 extending in the vehicle width direction and a pair of patch members 42 connected to both ends of the brace member 41. The ends of the brace member 41 and the pair of patch members 42 are connected by welding or the like, but are not limited to this. The brace member 41 and the pair of patch members 42 may be formed integrally.

[0020] The cross section of the brace member 41 is formed in a U-shape. The cross-sectional shape of the patch members 42 at both ends of the brace member 41 is a U-shape that opens outward in the vehicle width direction, as shown in Figure 3. The rear end of each shock absorber 3 is fitted into the opening of the patch member 42. This allows for the absorption of manufacturing tolerances of the cross member 4 in the vehicle width direction.

[0021] For example, a bolt 5 penetrates vertically through the rear end of each shock absorber 3 and the patch member 42 of the cross member 4. By tightening a nut 7 onto the penetrating bolt 5 via a washer 6, the rear end of each shock absorber 3 and the patch member 42 of the cross member 4 are fastened together by the fastening members, the bolt 5 and nut.

[0022] Here, for example, suppose the shock-absorbing material 3 is made of aluminum, and the case and cross member 4 of the battery pack 2 are made of iron. In this case, a displacement occurs between the two members due to the difference in the coefficient of thermal expansion between the shock-absorbing material 3 and the case and cross member 4 of the battery pack 2, and it is necessary to absorb this displacement.

[0023] For example, if bolts are arranged horizontally, a displacement of approximately 1 mm due to the aforementioned coefficient of thermal expansion will occur over a horizontal length of 1 m. Therefore, a structure is needed to absorb the displacement caused by the aforementioned coefficient of thermal expansion.

[0024] In contrast, in this embodiment, the length of the bolt 5 is longer than the vertical length of the cross member 4 by a predetermined value or more. This allows the bolt 5 to deform while absorbing the displacement due to the linear expansion coefficient by its length exceeding the predetermined value. The predetermined value is, for example, about 1 to 2 mm, which is a length that can absorb the above-mentioned displacement.

[0025] Next, the vehicle mounting structure 1 for the battery pack 2 and its manufacturing method will be described. First, a pair of shock-absorbing materials 3, which are longer than the battery pack 2 in the vehicle's longitudinal direction, are arranged in the vehicle's longitudinal direction so as to sandwich the outside of the battery pack 2 in the vehicle's width direction. Both ends of a cross member 4, which extends in the vehicle's width direction, are connected to the rear ends of each shock-absorbing material 3. Alternatively, the battery pack 2 may be placed between the pair of shock-absorbing materials 3 after connecting the cross member 4 and each shock-absorbing material 3.

[0026] While several embodiments of this disclosure have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims and their equivalents. [Explanation of symbols]

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

Claims

1. A vehicle mounting structure for a battery pack including a battery stack, A pair of shock-absorbing materials are provided, which extend in the vehicle longitudinal direction, sandwiching the outer side of the battery pack in the vehicle width direction, and which are longer in the vehicle longitudinal direction than the battery pack, A cross member extending in the vehicle width direction, with both ends connected to the ends of each of the impact absorbing materials, Equipped with, The cross-sectional shape of both ends of the aforementioned cross member is a U-shape that opens outward in the vehicle width direction, and the ends of each of the aforementioned shock-absorbing materials are fitted into the openings at both ends of the aforementioned cross member. Battery pack mounting structure for vehicles.

2. A vehicle mounting structure for a battery pack according to claim 1, The ends of each of the aforementioned shock-absorbing materials and both ends of the cross member are fastened together by fastening members that are longer than a predetermined value or more than the vertical length of the cross member, passing through in the vertical direction. Battery pack mounting structure for vehicles.

3. A method for manufacturing a vehicle mounting structure for a battery pack including a battery stack, A pair of shock-absorbing materials, longer in the vehicle's longitudinal direction than the aforementioned battery pack, are positioned in the vehicle's longitudinal direction so as to sandwich the outer side of the battery pack in the vehicle's width direction. The cross-sectional shape of both ends of the cross member is a U-shape that opens outward in the vehicle width direction, and both ends of the cross member extending in the vehicle width direction are connected to the ends of each of the shock-absorbing materials, and the ends of each of the shock-absorbing materials are fitted into the openings at both ends of the cross member. A method for manufacturing a vehicle mounting structure for a battery pack.

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