Battery pack

Abstract

Reduces the load applied to the battery pack by objects colliding with it. [Solution] The battery pack 12 comprises a battery module 14 and a housing case 16 that houses the battery module 14. The housing case 16 includes a lower case 17 and an upper case 18 having a box shape that opens downward. The upper case 18 includes a top wall 30, an upper enclosing wall 32 that extends downward from the periphery of the top wall 30 and surrounds at least a portion of the battery module 14, and an upper flange 34 that protrudes outward from the lower end of the upper enclosing wall 32. The upper flange 34 of the upper case 18 is fixed to the lower case 17. The upper flange 34 of the upper case 18 has a curled portion 36 that is bent upward and inward in a curled shape. The upper enclosing wall 32 of the upper case 18 has a bent portion 38 at a predetermined height from the upper flange 34 that changes the inclination angle of the outer surface toward the top wall 30 inward.

Description

Technical Field

[0001] This specification discloses a battery pack mounted on an electric vehicle.

Background Art

[0002] Conventionally, electric vehicles such as hybrid vehicles (HEV), plug-in hybrid vehicles (PHEV), and battery electric vehicles (BEV) are known. Electric vehicles include a battery pack that supplies power to a drive motor.

[0003] Patent Document 1 discloses a battery pack protection structure for a vehicle having a plurality of reinforcing members and a plurality of protection plates.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] There are known electric vehicles in which a battery pack is disposed in a place not visible to passengers, such as under a seat in a vehicle interior. In such vehicles, for example, when an object such as luggage between seats collides with the battery pack, a technique for protecting the battery pack from the impact load is required. As techniques for protecting the battery pack, for example, there are a technique of surrounding the periphery of the battery pack with a frame or a technique of securing a relatively large space between the housing and the battery stack inside the battery pack, but both have a problem that the exclusive volume of the battery pack becomes large.

[0006] From the perspective of maximizing interior space and ensuring sufficient volume for battery modules (battery stacks) to maximize battery capacity (vehicle range), there is a desire to reduce the size of the battery pack's protective structure. In other words, there is a need to protect the battery modules inside the battery pack without increasing the size of the battery pack's protective structure.

[0007] This specification discloses a structure that can reduce the load applied to a battery pack by an object colliding with it, in order to protect the battery module inside the battery pack without increasing the size of the battery pack's protective structure. [Means for solving the problem]

[0008] A battery pack disclosed herein comprises a battery module and a housing case for housing the battery module. The housing case includes a lower case and an upper case having a box shape that opens downward. The upper case includes a top wall, an upper enclosing wall extending downward from the periphery of the top wall and surrounding at least a portion of the battery module, and an upper flange projecting outward from the lower end of the upper enclosing wall. The upper flange of the upper case is fixed to the lower case. The upper flange of the upper case has a curled portion which is bent upward and inward. The upper enclosing wall of the upper case has a bent portion at a predetermined height from the upper flange which changes the inclination angle of the outer surface toward the top wall inward. [Effects of the Invention]

[0009] According to the technology disclosed herein, when an object collides with a battery pack, the contact area between the object and the housing case can be reduced by having the object come into contact with the curled or bent portion of the housing case. Furthermore, by positioning the curled or bent portion of the housing case that the object contacts (referred to as the contact portion) at a different height from the center of gravity of the object that is expected to collide with the battery pack, the orientation of the object after the collision can be disrupted. As a result, the load applied to the battery pack by the object can be reduced. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic cross-sectional view of the battery pack 12, and also shows the object 100 that collides with the curled portion 36 of the battery pack 12. [Figure 2] This is a cross-sectional view showing an object 101 colliding with the bent portion 38 of the battery pack 12. [Figure 3] This is a schematic cross-sectional view of another battery pack 12a, and also shows the object 102 that collides with the curled portion 36 of the battery pack 12a. [Modes for carrying out the invention]

[0011] Embodiments will be described below with reference to the drawings. In all drawings, equivalent elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0012] Figure 1 is a schematic cross-sectional view of the battery pack 12, showing an object 100 colliding with the curled portion 36 of the battery pack 12. The battery pack 12 is mounted on an electric vehicle. Electric vehicles include, for example, hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs). The battery module 14 of the battery pack 12 supplies power to the drive motor mounted on the electric vehicle.

[0013] At least a portion of the battery pack 12 is located inside the vehicle's interior. Figure 1 shows the battery pack 12 positioned on the floor 80 of the vehicle's interior. The battery pack 12 is positioned in a recess in the floor 80, with approximately the upper half of the battery pack 12 protruding upward from the floor 80. The surface of the floor 80 and the upper flange 34 of the battery pack 12's housing case 16 are at approximately the same height.

[0014] The battery pack 12 comprises a battery module 14 and a housing case 16 that houses the battery module 14. The battery module 14 includes a plurality of battery cells (not shown). The battery cells are, for example, rechargeable batteries such as nickel-metal hydride batteries and lithium-ion batteries.

[0015] The storage case 16 includes a lower case 17 and an upper case 18 positioned above the lower case 17. The lower case 17 has a box shape that opens upwards. The lower case 17 is made of metal, resin, or the like. The lower case 17 includes a bottom wall 20, a lower surrounding wall 22, and a lower flange 24.

[0016] The bottom wall 20 is located below the battery module 14. The lower enclosing wall 22 rises from the periphery of the bottom wall 20 and surrounds the lower part of the battery module 14. The lower flange 24 protrudes outward from the upper end of the lower enclosing wall 22. The lower flange 24 has edges that are bent downward and inward.

[0017] The upper case 18 has a box-like shape that opens downwards. The upper case 18 is made of metal, resin, or the like. The upper case 18 includes a top wall 30, an upper enclosing wall 32, and an upper flange 44. The top wall 30 is located above the battery module 14. The upper enclosing wall 32 extends downwards from the periphery of the top wall 30 and surrounds the upper part of the battery module 14. The upper flange 34 protrudes outwards from the lower end of the upper enclosing wall 32.

[0018] The upper flange 34 of the upper case 18 is fixed to the lower flange 24 of the lower case 17 by bolts or the like (not shown). The upper flange 34 has a curled portion 36 which is bent upward and inward in a curled shape. The curled portion 36 is the end of the upper flange 34 which is bent so that it has a substantially circular shape in cross-section and forms a hollow space. The upper enclosing wall 32 of the upper case 18 has a bent portion 38 at a predetermined height from the upper flange 34 (for example, at or near the midpoint of the height of the upper enclosing wall 32) which changes the inclination angle of the outer surface toward the top wall 30 inward.

[0019] According to the embodiments described above, for example, as the vehicle travels, an inertial force is generated in the object 100. As shown in FIG. 1, when the object 100 collides with the battery pack 12, the object 100 contacts the curled portion 36 of the upper case 18. Thereby, the contact area between the object 100 and the housing case 16 can be reduced.

[0020] Further, the curled portion 36, which is the portion of the upper case 18 that the object 100 contacts (referred to as the contact portion C1), can be provided at a height different from the center of gravity position CG of the object 100 where a collision is assumed. In FIG. 1, the center of gravity position CG of the object 100 and the contact portion C1 are separated by a distance L1 in the height direction. Due to the deviation in the height direction between the center of gravity position CG of the object 100 and the contact portion C1, the posture of the object 100 after the collision can be disturbed. That is, a large load input from the object 100 to the battery pack 12 can be converted into a rotational force with the contact portion C1 with the object 100 as the fulcrum. Therefore, the load input from the object 100 to the battery pack 12 can be reduced.

[0021] FIG. 2 is a cross-sectional view showing another object 101 that collides with the bent portion 38 of the battery pack 12. According to the embodiments described above, as shown in FIG. 2, when the object 101 collides with the battery pack 12, the object 101 contacts the bent portion 38 of the upper case 18. Thereby, the contact area between the object 101 and the housing case 16 can be reduced.

[0022] Further, the bent portion 38, which is the portion of the upper case 18 that the object 101 contacts (referred to as the contact portion C2), can be provided at a height different from the center of gravity position CG of the object 101 where a collision is assumed. In FIG. 2, the center of gravity position CG of the object 101 and the contact portion C2 are separated by a distance L2 in the height direction. Due to the deviation in the height direction between the center of gravity position CG of the object 101 and the contact portion C2, the posture of the object 101 after the collision can be disturbed. That is, a large load input from the object 101 to the battery pack 12 can be converted into a rotational force with the contact portion C2 with the object 101 as the fulcrum. Therefore, the load input from the object 101 to the battery pack 12 can be reduced.

[0023] According to the embodiments described above, the battery module 14 inside the battery pack 12 can be protected without increasing the size of the protection structure of the battery pack 12. For example, since the protection frame can be reduced or omitted, the exclusive volume of the battery pack 12 can be used to increase the battery capacity, and the cruising range of the vehicle can be extended.

[0024] FIG. 3 is a cross-sectional view schematically showing another battery pack 12a, and also shows an object 102 that collides with the curled portion 36 of the battery pack 12a. The battery pack 12a in FIG. 3 has a different arrangement of the battery pack and the shape of the housing case compared to the battery pack 12 in FIG. 1 described above.

[0025] As shown in FIG. 3, the battery pack 12a is arranged on the floor 80 of the passenger compartment. The battery pack 12a includes a housing case 16a. The lower case 17 of the housing case 16a has a tray shape and is shallower than the lower case 17 in FIG. 1. The upper case 18 of the housing case 16a in FIG. 3 has a large size in the height direction and surrounds almost the entire periphery of the battery module 14.

[0026] In the battery pack 12a of FIG. 3 as well, the same operational effects as those of the battery pack 12 in FIG. 1 can be obtained. The curled portion 36, which is the portion (referred to as the contact portion C3) of the upper case 18 that contacts the object 102, can be provided at a height different from the center of gravity position CG of the object 102 where a collision is assumed. In FIG. 3, the center of gravity position CG of the object 102 and the contact portion C3 are separated by a distance L3 in the height direction. Due to the deviation in the height direction between the center of gravity position CG of the object 102 and the contact portion C3, the posture of the object 102 after the collision can be disturbed. That is, a large load input from the object 102 to the battery pack 12a can be converted into a rotational force with the contact portion C3 with the object 102 as the fulcrum. Therefore, the load input from the object 102 to the battery pack 12a can be reduced. Although detailed description is omitted, the bent portion 38 of the housing case 16a in FIG. 3 can also obtain the same operational effects as the bent portion 38 of the housing case 16 in FIG. 1.

Description of Reference Numerals

[0027] 12,12a Battery pack, 14 Battery module, 16,16a Housing case, 17 Lower case, 18 Upper case, 20 Lower wall, 22 Lower surrounding wall, 24 Lower flange, 30 Top wall, 32 Upper surrounding wall, 34 Upper flange, 36 Curl section, 38 Bent section, 80 Floor, 100,101,102 Object, CG Center of gravity, C1 Contact point (rotation pivot), L1 Distance, C2 Contact point (rotation pivot), L2 Distance, C3 Contact point (rotation pivot), L3 Distance.

Claims

[Claim 1] Battery module and The battery module comprises a housing case for housing the battery module, The aforementioned storage case includes a lower case and an upper case having a box shape that opens downwards. The upper case includes a top wall, an upper enclosure wall extending downward from the periphery of the top wall and surrounding at least a portion of the battery module, and an upper flange projecting outward from the lower end of the upper enclosure wall. The upper flange of the upper case is fixed to the lower case. The upper flange of the upper case has a curled portion which is bent upwards and inwards in a curled shape. The upper enclosure wall of the upper case has a bent portion at a predetermined height from the upper flange that changes the inclination angle of the outer surface toward the top wall inward. A battery pack characterized by the following features.

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