Battery Mounting Structure of Frame Vehicle

Abstract

To inhibit failure of a battery even if a torsional angle of a side frame supporting a battery pack becomes large in a frame vehicle.SOLUTION: In a battery mounting structure of a frame vehicle 1, a battery pack 10 is supported by a pair of left and right side frames 3, 5 provided in the frame vehicle 1 and extending in a vehicle front-rear direction. The battery pack 10 includes a plurality of divided battery packs 10A, 10B, 10C, 10D, 10E divided in the vehicle front-rear direction. Each of the plurality of divided battery packs 10A, 10B, 10C, 10D, 10E is connected to a pair of left and right side frames 3, 5 via a support member 20.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a mounting structure of a battery in an electric vehicle, and particularly to a mounting structure of a battery in a frame-equipped electric vehicle (hereinafter, also simply referred to as a "frame vehicle").

Background Art

[0002] Conventionally, in an electric vehicle driven by electric power supplied from a battery, a battery pack in which secondary batteries such as lithium-ion batteries are systematized and put in a case is generally mounted in a manner supported by a pair of left and right side frames extending in the vehicle longitudinal direction.

[0003] For example, in Patent Document 1, in a so-called monocoque vehicle, a fixing structure of a battery pack of an electric vehicle is disclosed in which brackets fixed to a housing (case) of the battery pack are fastened to a pair of left and right side frames extending in the vehicle longitudinal direction and forming a part of the vehicle body skeleton.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, when a mounting structure in which a battery pack is simply fastened to a side frame, as in the case of Patent Document 1 above, is applied not to a monocoque vehicle but to a so-called frame vehicle in which a body (cab) is mounted on a side frame via a cab mount or the like, the following problems may occur.

[0006] That is, since the side frame and the body are integrated in a monocoque vehicle, the torsional rigidity of the side frame is relatively high. In contrast, in a frame vehicle where the side frame and the body are separated, the torsional rigidity of only the side frame is relatively low. Therefore, in a frame vehicle, if the same mounting structure is adopted as in a monocoque vehicle, where the battery pack is simply fastened to the side frame, the torsional angle of the side frame during running (such as when crossing a step) is large, and the battery pack fastened to it will be severely twisted, which may lead to battery failure.

[0007] The present invention has been made in view of such a point, and its object is to provide a battery mounting structure capable of suppressing battery failure even when the torsional angle of the side frame supporting the battery pack becomes large in a frame vehicle where the side frame and the body are separated.

Means for Solving the Problem

[0008] To achieve the above object, in the battery mounting structure of a frame vehicle according to the present invention, the battery pack is divided into a plurality in the vehicle longitudinal direction so that the individual divided battery packs are not severely twisted.

[0009] Specifically, the present invention targets the battery mounting structure of a frame vehicle in which a battery pack is supported by a pair of left and right side frames extending in the vehicle longitudinal direction provided in the frame vehicle.

[0010] And this battery mounting structure of the frame vehicle is characterized in that the battery pack is composed of a plurality of divided battery packs divided in the vehicle longitudinal direction, and the plurality of divided battery packs are respectively connected to the side frames. and adjacent said divided battery packs are connected to each other via elastic members It is characterized by the above.

[0011] In this configuration, the battery pack is composed of a plurality of divided battery packs that are divided in the longitudinal direction of the vehicle, and since these divided battery packs are each connected to the side frame, even if the torsional angle of the side frame extending in the longitudinal direction of the vehicle increases, each divided battery pack only tilts according to the torsional angle of each part of the side frame to which it is connected. That is, even if each divided battery pack tilts at different angles according to the torsional angle of each part of the side frame to which it is connected, since the divided battery packs are separated from each other, in other words, since the influence due to the difference in tilt is blocked, each divided battery pack is not greatly twisted, and thereby, battery failure can be suppressed. Also, since adjacent divided battery packs are connected to each other, in other words, since it is possible to handle the battery pack as one member, compared to the case where the battery pack is composed of completely separated divided battery packs, the convenience in the logistics of the battery pack and during vehicle assembly can be improved. Moreover, since the divided battery packs are connected to each other via elastic members, even if adjacent divided battery packs tilt at different angles according to the torsional angle of each part of the side frame, the influence due to the difference in tilt can be alleviated, thereby suppressing large torsion of each divided battery pack.

[0012] Further, in the battery mounting structure of the frame vehicle, a plurality of support members extending in the vehicle width direction and spanning the pair of left and right side frames are provided, and each of the divided battery packs may be connected to the side frame via the support member by being fastened to the support member.

[0013] According to this configuration, each divided battery pack can be easily supported on the side frame via a support member that connects the pair of left and right side frames in the vehicle width direction in the same manner as a cross member that supports a radiator, a spare tire, etc.

[0014] Furthermore, in the battery mounting structure of the frame vehicle, each of the support members may be connected to the side frame via a bolt or a rubber mount.

[0015] According to this configuration, when there are restrictions on the installation space, etc., each support member is connected to the side frame via a bolt, while when it is desired to suppress vibration transmission from the side frame to the battery pack, each support member is connected to the side frame via a rubber mount. In this way, a bolt or a rubber mount can be appropriately selected according to the design conditions of each vehicle.

[0016] In addition, in the battery mounting structure of the frame vehicle, both end portions in the vehicle width direction of each of the divided battery packs may be connected to the side frames.

[0017] According to this configuration, since both end portions in the vehicle width direction of each divided battery pack are directly connected to the side frames without passing through a support member spanning the side frames, the mounting structure can be simplified.

[0018] Furthermore, in the battery mounting structure of the frame vehicle, both end portions of each of the divided battery packs may be connected to the side frames via bolts or rubber mounts.

[0019] According to this configuration, even when the divided battery packs are directly connected to the side frames, bolts or rubber mounts can be appropriately selected according to the design conditions of each vehicle.

Effect of the Invention

[0023] As described above, according to the battery mounting structure of the frame vehicle according to the present invention, even when the torsional angle of the side frame supporting the battery pack becomes large, battery failures can be suppressed.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Mode for Carrying Out the Invention

[0025] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In each figure, arrow Fw indicates the front side in the vehicle longitudinal direction, arrow Lf indicates the left side in the vehicle width direction, and arrow Up indicates the upper side.

[0026] (Embodiment 1) -Frame vehicle- FIG. 1 is a plan view schematically showing the skeleton of a vehicle 1 to which the battery mounting structure according to the present embodiment is applied, and FIG. 2 is a cross-sectional view taken along the arrow direction of line II-II in FIG. 1. In FIG. 1, the left and right wheels 7 are not shown. As shown in FIG. 1, this vehicle 1 includes a pair of left and right side frames 3 and 5 extending in the vehicle longitudinal direction.

[0027] This vehicle 1 is configured as an electric vehicle driven by an electric motor (not shown) with a battery 11 as the main power source, and is configured as a so-called frame vehicle in which a body (cab) (not shown) is mounted on side frames 3 and 5 via a cab mount (not shown) attached to a plurality of mount attachment portions 9 fixed to the side frames 3 and 5. Therefore, in the following description, the vehicle 1 is also referred to as the "frame vehicle 1".

[0028] In this frame vehicle 1, a battery mounting structure is adopted in which a battery pack 10 obtained by systematizing the battery 11 and packaging it in a case is supported by a pair of left and right side frames 3 and 5 as shown in FIGS. 1 and 2.

[0029] -Battery Mounting Structure- Next, the battery mounting structure in the frame vehicle 1 will be described in detail. Prior to that, for easier understanding of this embodiment, the battery mounting structure of a conventional frame vehicle will be described.

[0030] FIG. 11 is a diagram schematically explaining the battery mounting structure of a conventional frame vehicle 101. In the conventional frame vehicle 101, as shown in FIG. 11(a), a structure in which the battery pack 110 is simply fastened to the side frames 103 and 105 is adopted, but such a battery mounting structure may cause the following problems.

[0031] That is, since the side frames and the body are integrated in a monocoque vehicle with high torsional rigidity, in the frame vehicle 101, the side frames 103 and 105 are separated from the body, so the torsional rigidity of only the side frames 103 and 105 is relatively low. Therefore, in the frame vehicle 101, when driving (such as when crossing a step), as shown in FIG. 11(c) from the state shown in FIG. 11(b), the front end of the left side frame 103 goes down while the rear end goes up, while the front end of the right side frame 105 goes up while the rear end goes down. When the torsional angle of the side frames 103 and 105 increases, the battery pack 110 fastened to the side frames 103 and 105 is greatly twisted, which may lead to battery failure.

[0032] Therefore, in the battery mounting structure of the frame vehicle 1 according to the present embodiment, as shown in FIG. 3(a), the single battery pack 110 that was conventionally supported by the side frames 103 and 105 is divided into a plurality in the vehicle longitudinal direction as shown in FIG. 3(b). Thus, even when the torsional angle of the side frames 3 and 5 to which the battery pack 10 is connected increases, the individual divided battery packs 10A, 10B, 10C, 10D, and 10E are not greatly twisted.

[0033] More specifically, the battery pack 10 is composed of five divided battery packs 10A, 10B, 10C, 10D, and 10E that are divided in the vehicle front-rear direction. The number of divisions of the battery pack 10 is determined according to the dimensions and characteristics of the side frames 3 and 5 and the battery pack 10. Specifically, the maximum torsional angle of the side frames 3 and 5 during driving is calculated. When the calculated maximum torsional angle exceeds the limit torsional angle of the battery pack 10, the battery pack 10 is divided into two. Then, at the span length divided into two, the maximum torsional angle of the side frames 3 and 5 during driving is calculated. When the calculated maximum torsional angle exceeds the limit torsional angle of the battery pack 10 divided into two, the battery pack 10 is further divided into three. Then, at the span length divided into three, the maximum torsional angle of the side frames 3 and 5 during driving is calculated. When the calculated maximum torsional angle exceeds the limit torsional angle of the battery pack 10 divided into three, the battery pack 10 is further divided into four. By repeating such a method until the maximum torsional angle of the side frames 3 and 5 during driving becomes equal to or less than the limit torsional angle of the divided battery pack 10, the number of divisions of the battery pack 10 is determined.

[0034] The split battery packs 10A, 10B, … thus divided into five parts are connected to the side frames 3 and 5 via the support members 20 as shown in FIGS. 1, 2, and 3(b). More specifically, the battery mounting structure of this embodiment includes the same number (five) of support members 20 as the split battery packs 10A, 10B, …. Each support member 20 is formed in a hollow rectangular cross-section shape made of, for example, metal that extends in the vehicle width direction and is spanned across the pair of left and right side frames 3 and 5. Each split battery pack 10A, 10B, … is supported by each support member 20 by being bolted in a state of being placed on each support member 20. Both end portions 20a of each support member 20 in the vehicle width direction are connected to the side frames 3 and 5 via the attachment portions 30. That is, the support member 20 is spanned across the pair of left and right side frames 3 and 5 in the frame vehicle 1 and performs the same function as a cross member that supports a radiator (not shown), a spare tire 8, etc.

[0035] FIG. 4 is a cross-sectional view schematically showing an example of the attachment portion 30. In the example shown in FIG. 4, the attachment portion 30 is composed of a rubber mount 30A. The rubber mount 30A includes a cylindrical collar 34, an upper plate 31 fixed to the upper end portion of the collar 34, a lower plate 33 fixed to the lower end portion of the collar 34, rubber 35 provided so as to cover the outer periphery of the collar 34 and adhered to the upper plate 31 and the lower plate 33, and a middle plate 32 attached to the central portion of the rubber 35 and moving up and down as the rubber 35 deforms. This rubber mount 30A is fixed to the side frame 3 in a state where the upper plate 31 is in contact with the lower surface of the side frame 3 by a bolt 36 inserted through the collar 34 from below.

[0036] At the vehicle-width direction end 20a of the support member 20, a bracket 21 is provided. By fastening such a bracket 21 and the middle plate 32 with bolts 23, each support member 20 is connected to the side frames 3, 5 via rubber mounts 30A. That is, each divided battery pack 10A, 10B,... is connected (supported) to the side frames 3, 5 via the support member 20 and the rubber mounts 30A. Thereby, since vibrations from the side frames 3, 5 are absorbed by the rubber mounts 30A, it is possible to suppress the transmission of vibrations to the battery 11.

[0037] -Function and Effect- FIG. 5 is a perspective view schematically showing the behavior of the divided battery packs 10A, 10B,... when the torsional angle of the side frames 3, 5 becomes large. Further, FIG. 6 is a view schematically showing the behavior of the divided battery packs 10A, 10B,... when the torsional angle of the side frames 3, 5 becomes large. FIG. 6(a) is a cross-sectional view taken along the arrow direction of line VI(a)-VI(a) in FIG. 1, FIG. 6(b) is a cross-sectional view taken along the arrow direction of line VI(b)-VI(b) in FIG. 1, and FIG. 6(c) is a cross-sectional view taken along the arrow direction of line VI(c)-VI(c) in FIG. 1.

[0038] For example, as shown in FIG. 5, when the torsional angle of the side frames 3, 5 becomes large such that the front end of the left side frame 3 drops while the rear end rises, and the front end of the right side frame 5 rises while the rear end drops, the divided battery packs 10A, 10B,... will each exhibit different behaviors.

[0039] More specifically, as shown in Fig. 6(a), when the left side frame 3 descends while the right side frame 5 ascends, the split battery pack 10A connected to the side frames 3 and 5 via the support member 20 will incline significantly downward to the left. In this way, even if the split battery pack 10A inclines significantly downward to the left, since the split battery pack 10A is separated from the adjacent split battery pack 10B, the split battery pack 10A and the split battery pack 10B only incline independently, and no torsional angle occurs between the two 10A and 10B.

[0040] Similarly, as shown in Fig. 6(c), when the left side frame 3 ascends while the right side frame 5 descends, the split battery pack 10E connected to the side frames 3 and 5 via the support member 20 will incline significantly downward to the right. In this way, even if the split battery pack 10E inclines significantly downward to the right, since the split battery pack 10E is separated from the adjacent split battery pack 10D, the split battery pack 10E and the split battery pack 10D only incline independently, and no torsional angle occurs between the two 10E and 10D.

[0041] Also, since the central portions of the side frames 3 and 5 in the vehicle front-rear direction hardly displace, the split battery pack 10C connected to such central portions via the support member 20 hardly displaces as shown in Fig. 6(b). Thus, since the split battery pack 10C is separated from the front and rear split battery packs 10B and 10D, even if the split battery pack 10B inclines downward to the left and the split battery pack 10D inclines downward to the right, it is not affected by these and does not enter a relationship where a torsional angle occurs.

[0042] That is, in the battery mounting structure of the frame vehicle 1 according to the present embodiment, even when the torsional angles of the side frames 3 and 5 increase, each of the divided battery packs 10A, 10B,... only tilts according to the torsional angle of each part of the side frames 3 and 5 to which they are connected. In this way, even if each of the divided battery packs 10A, 10B,... tilts at different angles according to the torsional angle of each part of the connected side frames 3 and 5, since the divided battery packs 10A, 10B,... are separated from each other, the divided battery packs 10A, 10B,... are not greatly twisted (they are only twisted slightly according to the relatively small torsional angle of each part of the side frames 3 and 5 with a short span length), and thereby, the failure of the battery 11 can be suppressed.

[0043] (Embodiment 2) This embodiment is different from the above Embodiment 1 in that the divided battery packs 10A, 10B,... themselves are connected to the side frames 3 and 5. Hereinafter, the description will focus on the differences from Embodiment 1.

[0044] FIG. 7 is a cross-sectional view schematically showing the battery mounting structure according to the present embodiment, and FIG. 8 is a cross-sectional view schematically showing an example of the attachment portion 30. Since the support modes of the five divided battery packs 10A, 10B,... are substantially the same, hereinafter, the divided battery pack 10C will be described as a representative. In the present embodiment, as shown in FIG. 7, both end portions in the vehicle width direction of the divided battery pack 10C are connected to the side frames 3 and 5 via the attachment portion 30.

[0045] Similar to Embodiment 1, the attachment portion 30 may be constituted by the rubber mount 30A, or different from Embodiment 1, it may be constituted by the bolt 30B.

[0046] For example, when the attachment portion 30 is constituted by the rubber mount 30A, the middle plate 32 of the rubber mount 30A fixed to the side frame 3 as shown in FIG. 4 above and the end portion of the divided battery pack 10C may be connected.

[0047] On the other hand, when the mounting portion 30 is constituted by bolts 30B, as shown in FIG. 8, a bracket 13 is provided at the end of the divided battery pack 10C, and such a bracket 13 may be fastened to the lower surface of the side frame 3 with bolts 30B.

[0048] -Function and Effect- According to the present embodiment, since both ends in the vehicle width direction of each of the divided battery packs 10A, 10B,... are directly connected to the side frames 3 and 5 without passing through the support member 20, the mounting structure can be simplified as compared with the first embodiment. Further, if the mounting portion 30 is constituted by bolts 30B, the mounting structure can be made even simpler.

[0049] (Embodiment 3) This embodiment is different from the above-described embodiment 2 in that adjacent divided battery packs 10A, 10B,... are connected to each other via an elastic member. Hereinafter, the description will focus on the differences from embodiment 2.

[0050] FIG. 9 is a plan view schematically showing the battery mounting structure according to the present embodiment. In the present embodiment, as shown in FIG. 9, adjacent divided battery packs 10A, 10B,... are connected to each other via an elastic member 40. Note that the divided battery packs 10A, 10B,... are connected to the side frames 3 and 5 via the mounting portion 30 at both ends in the vehicle width direction, similarly to the second embodiment.

[0051] The elastic member 40 connects the divided battery pack 10A and the divided battery pack 10B, the divided battery pack 10B and the divided battery pack 10C, the divided battery pack 10C and the divided battery pack 10D, and the divided battery pack 10D and the divided battery pack 10E in the front-rear direction, respectively. The elastic member 40 is, for example, soft rubber around the axis in the vehicle front-rear direction, and even if one of the adjacent divided battery packs tilts according to the torsional angle of each part of the connected side frames 3 and 5, it does not affect the tilt of the other divided battery pack.

[0052] -Function and Effect- According to the present embodiment, since the adjacent divided battery packs 10A, 10B, … are connected to each other, in other words, since the battery pack 10 can be handled as one member, the convenience in logistics of the battery pack 10 and during vehicle assembly can be improved as compared with the case where the battery pack 10 is configured by completely separated divided battery packs 10A, 10B, ….

[0053] Moreover, since the divided battery packs 10A, 10B, … are connected to each other via the flexible elastic member 40 around the axis in the vehicle front-rear direction, even if the adjacent divided battery packs 10A, 10B, … are inclined at different angles according to the torsional angle of each part of the side frames 3, 5, the influence due to the difference in inclination can be alleviated, and thereby, it is possible to suppress each divided battery pack 10A, 10B, … from being greatly twisted.

[0054] (Other Embodiments) The present invention is not limited to the embodiments, and can be implemented in various other forms without departing from its spirit or main features.

[0055] In the above-described Embodiment 1, the attachment portion 30 is configured by the rubber mount 30A, and the support member 20 is connected to the side frames 3, 5 via the rubber mount 30A. However, the present invention is not limited to this, and the attachment portion 30 may be configured by bolts 30B, and for example, the bracket 21 may be bolted to the lower surface of the side frame 3. In this way, even when there are restrictions on the installation space or the like, the support member 20 can be easily connected to the side frames 3, 5 via the bolts 30B.

[0056] Also, in the above-described Embodiment 3, as in the above-described Embodiment 2, the divided battery packs 10A, 10B, … directly connected to the side frames 3, 5 are connected by the elastic member 40. However, the present invention is not limited to this, and for example, as in the above-described Embodiment 1, the divided battery packs 10A, 10B, … connected to the side frames 3, 5 via the support member 20 may be connected by the elastic member 40.

[0057] Furthermore, in each of the above embodiments, the attachment portion 30 is provided on the lower surface of the side frame 3. However, the present invention is not limited to this, and depending on the constraints such as the installation space, for example, as shown in FIG. 10, the attachment portion 30 may be provided on the side surface of the side frame 3, or although not shown, the attachment portion 30 may be provided on the upper surface of the side frame 3.

[0058] Thus, the above-described embodiments are merely illustrative in all respects and should not be construed in a limiting sense. Furthermore, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

Industrial Applicability

[0059] According to the present invention, even when the torsional angle of the side frame increases, it is possible to suppress battery failures. Therefore, it is extremely beneficial to apply it to a battery mounting structure of a frame vehicle that supports a battery pack with a side frame.

Explanation of Reference Numerals

[0060] 1 Frame vehicle 3 Side frame 5 Side frame 10 Battery pack 10A Divided battery pack 10B Divided battery pack 10C Divided battery pack 10D Divided battery pack 10E Divided battery pack 20 Support member 30A Rubber mount 30B Bolt 40 Elastic member

Claims

1. A battery mounting structure for a frame vehicle, wherein a battery pack is supported by a pair of left and right side frames extending in the longitudinal direction of the vehicle and provided on the frame vehicle, the battery pack is composed of a plurality of divided battery packs divided in the longitudinal direction of the vehicle, the plurality of divided battery packs are respectively connected to the side frames, and the adjacent divided battery packs are connected to each other via elastic members. A battery mounting structure for a frame vehicle, characterized in that.

2. In the battery mounting structure for a frame vehicle according to Claim 1 above, it is provided with a plurality of support members extending in the vehicle width direction and spanning the pair of left and right side frames, each of the divided battery packs is connected to the side frame via the support member by being fastened to the support member. A battery mounting structure for a frame vehicle, characterized in that.

3. In the battery mounting structure for a frame vehicle according to Claim 2 above, each of the support members is connected to the side frame via a bolt or a rubber mount. A battery mounting structure for a frame vehicle, characterized in that.

4. In the battery mounting structure for a frame vehicle according to Claim 1 above, both ends in the vehicle width direction of each of the divided battery packs are connected to the side frame. A battery mounting structure for a frame vehicle, characterized in that.

5. In the battery mounting structure for a frame vehicle according to Claim 4 above, both ends of each of the divided battery packs are connected to the side frame via a bolt or a rubber mount. A battery mounting structure for a frame vehicle, characterized in that.

Images