Battery pack structure

Abstract

To provide a battery pack structure in which a transmission path of a side collision load is secured upon a side collision of a vehicle.SOLUTION: In a battery case 32, a rib 46 extending between side walls 40 and 42 is provided, so that rigidity of the battery case 32 itself can be improved as compared with a case where the rib 46 is not provided. Further, upon a side collision of a vehicle 12, a side collision load input to a rocker 16 is transmitted to the battery case 32 side through a fastening part 52. The fastening part 52 is provided on an extension line of the rib 46 in a vehicle width direction in a vehicle plan view, so that the side collision load transmitted to the battery case 32 side through the fastening part 52 is transmitted from one side wall 40 side to the rib 46, and is transmitted to the other side wall 42 side.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a battery pack structure. [Background technology]

[0002] In the electric vehicle described in Patent Document 1 below, a substantially rectangular parallelepiped battery storage space is formed by a space defined by a pair of left and right sill beams (sometimes called rockers), a front cross member, a rear cross member, and a cooling plate, and multiple batteries are stored in this battery storage space. In other words, the multiple batteries are surrounded by a so-called vehicle frame (sometimes called a vehicle skeleton) defined by the rockers, front cross member, and rear cross member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Publication number CN114940214 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned prior art, there is a concern about the transmission path of a side collision load input to a battery pack made up of multiple batteries during a side collision of the vehicle (hereinafter referred to as "vehicle side collision").

[0005] SUMMARY OF THE PRESENT INVETION The present invention has been made in consideration of the above circumstances, and has an object to provide a battery pack structure that ensures a transmission path for a side collision load in the event of a side collision of a vehicle. [Means for solving the problem]

[0006] The battery pack structure of the invention described in claim 1 comprises a battery pack body in which battery cells are housed extending along the vehicle width direction and arranged along the vehicle fore-and-aft direction, a first rib that protrudes along the vehicle width direction at a bottom wall that constitutes a part of the battery pack body between the battery cells arranged along the vehicle fore-and-aft direction and that constitutes another part of the battery pack body and is bridged between a pair of side walls that extend along the vehicle fore-and-aft direction at both ends in the vehicle width direction, and a fastening portion that is provided on the outside of the side wall of the battery pack body, is positioned on an extension of the first rib in the vehicle width direction when viewed from above the vehicle, constitutes a part of the vehicle skeleton, and is fastened to a rocker that extends along the vehicle fore-and-aft direction on both outer sides in the vehicle width direction.

[0007] The battery pack structure according to the invention recited in claim 1 includes a battery pack body, a first rib, and a fastening portion. The battery pack body accommodates battery cells extending along the vehicle width direction and arranged along the vehicle front-rear direction. The first rib protrudes along the vehicle width direction between the battery cells arranged along the vehicle front-rear direction on a bottom wall constituting a part of the battery pack body, and bridges between a pair of side walls constituting another part of the battery pack body at both ends in the vehicle width direction and extending along the vehicle front-rear direction.

[0008] Here, the battery pack body is provided with a fastening portion on the outer side of the side wall, which is disposed on an extension of the first rib in the vehicle width direction in a plan view of the vehicle, and is fastened to a rocker that constitutes a part of the vehicle frame and extends in the vehicle front-rear direction on both outer sides in the vehicle width direction.

[0009] In the present invention, the first rib that spans between the pair of side walls is provided in the battery pack body, which makes it possible to improve the rigidity of the battery pack body itself compared to a case in which the first rib is not provided, thereby suppressing flexural deformation of the battery pack body in the present invention.

[0010] In addition, in the present invention, in the event of a side collision of the vehicle, the side impact load input to the rocker is transmitted to the battery pack main body via the fastening portion. Since the fastening portion is provided on an extension line of the first rib in the vehicle width direction in a plan view of the vehicle, the side impact load transmitted to the battery pack main body via the fastening portion is transmitted from one side wall side to the first rib and then to the other side wall side. In this way, in the present invention, a transmission path from one rocker side to the other rocker side is secured for the side impact load.

[0011] The battery pack structure of the invention described in claim 2 is the battery pack structure of the invention described in claim 1, further comprising a second rib provided on a bottom wall of the battery pack and transmitting a load input along the vehicle width direction to the opposite side of the vehicle width direction along the vehicle width direction.

[0012] In the battery pack structure of the invention described in claim 2, a second rib is provided on the bottom wall of the battery pack body, and the second rib is configured to transmit a load (side impact load) input along the vehicle width direction to the opposite side of the vehicle width direction along the vehicle width direction.

[0013] In this way, by providing the second rib on the bottom wall of the battery pack body, it is possible to improve the rigidity of the battery pack body itself compared to a case where the second rib is not provided. Note that the second rib provided on the bottom wall of the battery pack body may be one that protrudes from the bottom wall of the battery pack body toward the upper side in the vertical direction of the vehicle, or one that protrudes from the bottom wall of the battery pack body toward the lower side in the vertical direction of the vehicle.

[0014] The battery pack structure of the invention described in claim 3 is the battery pack structure of the invention described in claim 2, in which the second rib protrudes downward in the vehicle vertical direction from the bottom wall of the battery pack body and is configured to overlap with the rocker in a side view of the vehicle.

[0015] In the battery pack structure according to the invention described in claim 3, the second rib protrudes downward in the vehicle vertical direction from the bottom wall of the battery pack body and is provided outside the battery pack body. As a comparative example, when the second rib protrudes upward in the vehicle vertical direction from the bottom wall of the battery pack body, the second rib is provided inside the storage section of the battery pack body. On the other hand, when the second rib protrudes downward in the vehicle vertical direction from the bottom wall of the battery pack body, the second rib is provided outside the battery pack body.

[0016] Therefore, in the present invention, by having the second rib protrude downward in the vehicle vertical direction from the bottom wall of the battery pack body, the volume within the storage portion can be increased compared to when the second rib is provided within the storage portion of the battery pack body.

[0017] Furthermore, when the second rib protrudes downward in the vehicle vertical direction from the bottom wall of the battery pack body, the second rib is set to overlap with the rocker when viewed from the side of the vehicle, making it possible to transmit side collision load to the opposite side in the vehicle width direction via the second rib.

[0018] Therefore, in the present invention, it is possible to improve the rigidity of the battery pack body while ensuring the battery capacity.

[0019] The battery pack structure of the invention described in claim 4 is a battery pack structure of the invention described in any one of claims 1 to 3, in which the fastening portion is provided on a cover that covers the storage portion of the battery pack main body, and the cover forms a floor that constitutes the floor portion of the vehicle interior.

[0020] In the battery pack structure according to the invention recited in claim 4, a fastening portion is provided on a cover that closes the housing portion of the battery pack body. This cover constitutes the floor that constitutes the floor portion of the vehicle interior, which eliminates the need for a separate floor panel, making it possible to reduce the number of parts. Effect of the Invention

[0021] As described above, in the battery pack structure according to the present invention, a transmission path for a side collision load can be ensured in the event of a side collision of the vehicle. [Brief description of the drawings]

[0022] [Figure 1] 1 is a perspective view showing a configuration of a vehicle to which a battery pack structure according to an embodiment of the present invention is applied, viewed from diagonally above on the left side; [Diagram 2] 1 is a plan view showing a partially cutaway state illustrating the configuration of a vehicle to which a battery pack structure according to an embodiment of the present invention is applied. [Diagram 3] 3 is a schematic cross-sectional view taken along line AA in FIG. 2. [Figure 4] 3 is a schematic cross-sectional view taken along line BB in FIG. 2. [Diagram 5] 4 is a schematic cross-sectional view corresponding to FIG. 3, showing the configuration of a modified example of a vehicle to which the battery pack structure according to the present embodiment is applied. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] The battery pack structure according to the embodiment of the present invention will be described with reference to the drawings. Note that the arrows FR, UP, and RH shown in each drawing indicate the forward direction (travel direction), upward direction, and rightward direction, respectively, of a vehicle to which the battery pack structure according to the present embodiment is applied. Hereinafter, when the directions of front-rear, left-right, and up-down are simply used for the description, they indicate front-rear in the front-rear direction of the vehicle, left-right in the left-right direction of the vehicle (vehicle width direction), and up-down in the up-down direction of the vehicle, unless otherwise specified. Also, in each drawing, some members and some symbols may be omitted in order to make the drawings easier to see.

[0024] As shown in Fig. 1, a vehicle (vehicle body) 12 to which a battery pack structure 10 according to an embodiment of the present invention is applied includes a pair of left and right rockers 16, 18 that form a vehicle frame and extend in the front-rear direction of the vehicle at lower ends in the vehicle width direction of a passenger compartment 14 (see Fig. 3), a front cross member 20 provided along the vehicle width direction at the front ends of the rockers 16, 18, and a rear cross member 22 provided along the vehicle width direction at the rear ends of the left and right rockers 16, 18. Front side members 24 extend along the vehicle front-rear direction at both ends in the vehicle width direction of the front cross member 20, and rear side members 26 extend along the vehicle front-rear direction at both ends in the vehicle width direction of the rear cross member 22.

[0025] The vehicle 12 in this embodiment is an electric vehicle that runs using the driving force of an electric motor (not shown), and a battery pack (battery pack main body) 30 that houses a plurality of battery cells 28 that supply driving power to the electric motor is provided under the vehicle 12.

[0026] (Battery pack structure) Here, the configuration of the battery pack structure according to this embodiment will be described.

[0027] 1, the battery pack structure 10 according to this embodiment includes a battery pack 30. The battery pack 30 is made of a light metal such as an aluminum alloy, and includes a box-shaped battery case (battery pack body) 32 that is rectangular in shape with the longitudinal direction of the vehicle in a plan view and open at the top. Note that, in addition to metal, resin members such as carbon fiber reinforced plastic (CFRP) and glass fiber reinforced plastic (GFRP) may also be used. The same applies to a cover 48 and an undercover 60 described below.

[0028] The battery case 32 is composed of a bottom wall 34, a front wall 36 erected from the front end of the bottom wall 34 in the fore-and-aft direction of the vehicle, a rear wall 38 opposing the front wall 36 and erected from the rear end of the bottom wall 34 in the fore-and-aft direction of the vehicle, and a pair of side walls 40, 42 erected from both ends of the bottom wall 34 in the width direction of the vehicle and facing each other.

[0029] In this embodiment, for example, the distance between the front wall 36 and the rear wall 38 of the battery case 32 is formed to be slightly narrower than the distance between the front cross member 20 and the rear cross member 22. In addition, the distance between the side walls 40 and 42 of the battery case 32 is formed to be slightly narrower than the distance between the rockers 16 and 18. As a result, the battery case 32 in this embodiment can be disposed within the space surrounded by the rockers 16, 18, the front cross member 20, and the rear cross member 22 that constitute the vehicle framework.

[0030] A plurality of thin plate-like battery cells 28 each having a substantially rectangular shape with the vehicle width direction as its longitudinal direction are housed in a storage section 44 of the battery case 32, which is constituted by the bottom wall 34, the front wall 36, the rear wall 38, and the side walls 40, 42, and the battery cells 28 are arranged along the vehicle front-rear direction. Note that, although the storage section 44 is constituted by a single space here, the storage section 44 may be divided into a plurality of sections.

[0031] Meanwhile, a rib (first rib) 46 is provided protruding along the vehicle width direction between adjacent battery cells 28 in the vehicle front-rear direction at approximately the center of the bottom wall 34 of the battery case 32, and the rib 46 spans between the side walls 40 and 42. Here, for example, the height of the rib 46 is set to be approximately half that of the side wall 40, and the dimension in the height direction is set to be greater than the dimension in the vehicle front-rear direction, but this is not limited to this (described later).

[0032] The storage section 44 of the battery case 32, with the multiple battery cells 28 stored therein, is closed by a cover 48 that has a rectangular plate shape in a plan view. The cover 48 is made of a light metal such as an aluminum alloy, has a plate shape with its thickness direction aligned in the vertical direction of the vehicle, and is integrated with the battery case 32 by welding or the like.

[0033] Both ends (parts) 48A, 48B of the cover 48 in the vehicle width direction protrude outward in the vehicle width direction from the side walls 40, 42 of the battery case 32. The both ends 48A, 48B of the cover 48 can be fastened to the upper walls 16A, 18A of the rockers 16, 18, for example, via fastening parts 50, 52, 54 arranged along the vehicle front-rear direction. Note that the fastening method at the fastening parts 50, 52, 54 can be riveting, spot welding, etc., in addition to bolt fastening. This can be changed as appropriate depending on the materials to be fastened.

[0034] Here, in this embodiment, the fastening portion 52 is provided on an extension line of the rib 46 in the vehicle width direction when seen from above the vehicle. In this embodiment, the fastening portions 50, 52, 54 provided on both end portions 48A, 48B of the cover 48 in the vehicle width direction are formed continuously along the vehicle front-rear direction, but the fastening portions 50, 52, 54 may be formed intermittently.

[0035] Meanwhile, ribs (second ribs) 56, 58 protrude in the vehicle width direction from the bottom wall 34 of the battery case 32. A plurality of the ribs 56, 58 are arranged in the vehicle front-rear direction. In this embodiment, the rib 56 is provided in front of the rib 46, and the rib 58 is provided behind the rib 46 in a plan view.

[0036] An undercover 60 is provided below the ribs 56, 58 and is disposed approximately parallel to the bottom wall 34 of the battery case 32. The undercover 60 is made of a light metal such as an aluminum alloy, has a plate shape with its thickness direction aligned in the vertical direction of the vehicle, and serves to prevent interference with the road surface.

[0037] 3, a front end 60A of the undercover 60 is fastened to the lower wall 20A of the front cross member 20 via a fastening portion 61, and a rear end 60B of the undercover 60 is fastened to the lower wall 22A of the rear cross member 22 via a fastening portion 63. Note that, as with the fastening portions 50, 52, and 54, fastening methods at the fastening portions 61 and 63 include riveting, spot welding, and the like, in addition to bolt fastening. Further, at the fastening portions 61 and 63, a spacer 65 is provided to maintain a gap between the bottom wall 34 of the battery case 32 and the undercover 60.

[0038] 2, both end portions 60C, 60D of the undercover 60 in the vehicle width direction are fastened to the lower wall 18B (see FIG. 4) of the rocker 18, and the ribs 56, 58 are disposed between the rockers 16 and 18. The rockers 16 and 18 have substantially the same configuration. For this reason, FIG. 4 shows only the rocker 18 side as a representative of both.

[0039] 4, the height of the rib 46 is set to be slightly lower than the side wall 42. By increasing the height of the rib 46 in this manner, for example, the inside of the rib 46 can be formed to be hollow, and cooling piping can be arranged in the hollow space through which a cooling medium flows to cool the battery cells 28. In this case, wiring such as cables and harnesses may be arranged in addition to the cooling piping.

[0040] On the other hand, the rocker 18 has a closed cross-sectional structure including a closed cross-sectional portion 66 composed of an outer portion 62 and an inner portion 64. In the closed cross-sectional portion 66, an EA portion (shock absorbing portion) 68 formed in a straight line bridging the outer portion 62 and the inner portion 64, and an EA portion 70 formed in a ladder shape are provided. In this way, by providing the EA portions 68, 70 in the closed cross-sectional portion 66 of the rocker 18, it becomes possible to absorb a side impact load input during a side impact of the vehicle due to plastic deformation of the EA portions 68, 70. The EA portion 70 is set so as to overlap with the rib 46 in a side view of the vehicle.

[0041] Further, the end portion of the cover 48 in the vehicle width direction is fastened to the upper wall 18A of the inner portion 64 of the rocker 18, and both end portions 60C, 60D (see FIG. 2) in the vehicle width direction of the undercover 60 are fastened to the lower wall 18B of the inner portion 64. Note that the configuration and shape of the rocker 18 are merely an example, and are not limited to this configuration and shape.

[0042] (Actions and Effects of Battery Pack Structure) Next, the operation and effects of the battery pack structure according to this embodiment will be described.

[0043] 1 and 2, in this embodiment, the battery pack structure 10 includes a battery case 32, a rib 46, and a fastening portion 52. The battery case 32 accommodates battery cells 28 extending along the vehicle width direction and arranged along the vehicle front-rear direction. The rib 46 protrudes along the vehicle width direction on the bottom wall 34 of the battery case 32 between the battery cells 28 arranged along the vehicle front-rear direction, and spans between the side walls 40, 42 of the battery case 32.

[0044] In this manner, in the present embodiment, by providing the rib 46 bridging between the side walls 40, 42 inside the battery case 32, it is possible to improve the rigidity of the battery case 32 itself compared to a case in which the rib 46 is not provided. As a result, in the present embodiment, bending deformation of the battery case 32 is suppressed.

[0045] In this embodiment, fastening portions 52 between the cover 48 and the rockers 16, 18 are provided on an extension line of the rib 46 in the vehicle width direction in a plan view of the vehicle. For this reason, in this embodiment, in the event of a side collision of the vehicle 12, the side collision load input to the rocker 18 is transmitted to the battery case 32 side via the fastening portions 52. Since the fastening portions 52 are provided on an extension line of the rib 46 in the vehicle width direction in a plan view of the vehicle, the side collision load transmitted to the battery case 32 side via the fastening portions 52 is transmitted from one side wall 42 side to the rib 46 and then to the other side wall 40 side.

[0046] In this manner, in this embodiment, a transmission path is secured for a side impact load from one rocker 18 to the other rocker 16. In addition, by providing the fastening parts 52 between the cover 48 and the rockers 16, 18 on the extension line of the rib 46 in the vehicle width direction when viewed from above the vehicle, the effect of positioning the fastening parts 52 is also obtained.

[0047] In addition, the rib 46 is set to overlap with the EA portion 70 provided in the closed cross-sectional portion 66 of the rocker 18 shown in Fig. 4 in a side view of the vehicle. Therefore, a side collision load input during a side collision of the vehicle can be reliably transmitted to the rib 46 side via the EA portion 70.

[0048] In this embodiment, as shown in Fig. 3, ribs 56, 58 are provided on the bottom wall 34 of the battery case 32, and the ribs 56, 58 are set to transmit a side impact load along the vehicle width direction to the opposite side in the vehicle width direction. In this way, by providing the ribs 56, 58 on the bottom wall 34 of the battery case 32, it is possible to improve the rigidity of the battery case 32 itself compared to a case in which the ribs 56, 58 are not provided. In this embodiment, by providing a plurality of ribs 56, 58, it is possible to disperse the side impact load.

[0049] In addition, the ribs 56, 58 provided on the bottom wall 34 of the battery case 32 may protrude from the bottom wall 34 of the battery case 32 toward the upper side of the vehicle, or may protrude from the bottom wall 34 of the battery case 32 toward the lower side of the vehicle.

[0050] 5 as a comparative example, when the ribs 72, 74 protrude from the bottom wall 34 of the battery case 32 toward the upper side of the vehicle, the ribs 72, 74 are provided inside the battery case 32. Therefore, the ribs 72, 74 are provided between the pair of side walls 40, 42 of the battery case 32 together with the rib 46. This makes it possible to further improve the rigidity of the battery case 32 itself.

[0051] On the other hand, in this embodiment, as shown in Fig. 3, the ribs 56, 58 protrude from the bottom wall 34 of the battery case 32 towards the vehicle lower side. In this case, the ribs 56, 58 are provided on the outside of the battery case 32. In this embodiment, as shown in Fig. 4, the ribs 56, 58 are set to overlap with the rockers 16, 18 in a side view of the vehicle, so that the ribs 56, 58 can transmit a load input along the vehicle width direction to the opposite side in the vehicle width direction along the vehicle width direction.

[0052] Here, in this embodiment, as shown in FIG. 3, the ribs 56, 58 protrude from the bottom wall 34 of the battery case 32 toward the lower side of the vehicle, so that the volume within the storage section 44 can be increased compared to the case where ribs 72, 74 (see FIG. 5) are provided within the storage section 44 of the battery case 32.

[0053] Therefore, in this embodiment, it is possible to improve the rigidity of the battery case 32 while ensuring the battery capacity. However, the present invention also includes a configuration in which the ribs 72, 74 protrude from the bottom wall 34 of the battery case 32 toward the upper side of the vehicle, as shown in Fig. 5.

[0054] In this embodiment, the fastening portion 52 is provided on the cover 48 that covers the storage portion 44 of the battery case 32. The floor is formed by this cover 48. As a result, in this embodiment, it is possible to reduce the number of parts and the number of work steps compared to, for example, a comparative example (not shown) in which a separate floor panel is provided above the cover 48.

[0055] <Additional Notes> The battery pack structure according to the present invention may be formed by appropriately combining the following configurations.

[0056] (Configuration 1) The battery pack structure includes a battery pack body in which battery cells are housed extending along the vehicle width direction and arranged along the vehicle fore-and-aft direction, a first rib that protrudes along the vehicle width direction at a bottom wall that constitutes part of the battery pack body between the battery cells arranged along the vehicle fore-and-aft direction and that constitutes another part of the battery pack body and is bridged between a pair of side walls that extend along the vehicle fore-and-aft direction at both ends in the vehicle width direction, and a fastening portion that is provided on the outside of the side wall of the battery pack body, is positioned on an extension of the first rib in the vehicle width direction when viewed from above the vehicle, constitutes part of the vehicle skeleton, and is fastened to a rocker that extends along the vehicle fore-and-aft direction on both outer sides in the vehicle width direction.

[0057] (Configuration 2) The battery pack further includes a second rib that is provided on a bottom wall of the battery pack body and transmits a load input along the vehicle width direction to the opposite side in the vehicle width direction along the vehicle width direction.

[0058] (Configuration 3) The second rib protrudes downward in the vehicle up-down direction from a bottom wall of the battery pack body and is set so as to overlap with the locker in a side view of the vehicle.

[0059] (Configuration 4) The fastening portion is provided on a cover that closes the storage portion of the battery pack body, and the cover constitutes a floor that constitutes the floor portion of the vehicle interior.

[0060] In addition, the present invention can be implemented in various modifications without departing from the spirit and scope of the present invention. Furthermore, the scope of the present invention is not limited to the above-described embodiment. [Explanation of symbols]

[0061] 10 Battery pack structure 12 Vehicles 16 Rocca 18 Rocca 28 Battery Cells 30 Battery pack (battery pack body) 32 Battery case (battery pack body) 34 Bottom Wall 40 side wall 42 Side wall 44 Storage unit 46 Rib (1st Rib) 48 Cover 52 Fastening part 56 Rib (2nd Rib) 58 Rib (2nd Rib) 72 Rib (2nd Rib) 74 Rib (2nd Rib)

Claims

1. a battery pack body in which the battery cells are housed in a state in which the battery cells extend along a vehicle width direction and are arranged along a vehicle front-rear direction; a first rib that is provided in a bottom wall constituting a part of the battery pack body, protruding along a vehicle width direction between the battery cells arranged along the vehicle front-rear direction, and that is bridged between a pair of side walls that constitute another part of the battery pack body and extend along the vehicle front-rear direction at both ends in the vehicle width direction; a fastening portion provided on an outer side of a side wall of the battery pack body, disposed on an extension line of the first rib in a vehicle width direction in a plan view of the vehicle, and fastened to a rocker that constitutes a part of a vehicle frame and extends along a vehicle front-rear direction on both outer sides in the vehicle width direction; A battery pack structure comprising:

2. 2. The battery pack structure according to claim 1, further comprising a second rib provided on a bottom wall of the battery pack body for transmitting a load input along the vehicle width direction to the opposite side of the vehicle width direction along the vehicle width direction.

3. 3. The battery pack structure according to claim 2, wherein the second rib protrudes downward in the vehicle up-down direction from a bottom wall of the battery pack body and is set so as to overlap with the locker in a side view of the vehicle.

4. The battery pack structure according to any one of claims 1 to 3, wherein the fastening portion is provided on a cover that covers the storage portion of the battery pack body, and the cover forms a floor that constitutes the floor portion of the vehicle interior.

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