Battery mounting structure of EV vehicles

Abstract

To provide a battery mounting structure for an EV vehicle that can mitigate impact loads from outside the vehicle to the battery pack and protect the battery pack. [Solution] The battery mounting structure for an EV vehicle of the present invention is configured by arranging and connecting multiple panel components 21, which are located below the floor panel 1F of the vehicle 1 and extend in the vehicle width direction so as to span between a pair of side members 1S of the vehicle frame, along the vehicle's front-rear direction, thereby forming an under panel 20 that serves as a mounting base for the battery pack 10.

Description

Technical Field

[0001] This disclosure relates to a battery mounting structure for an EV vehicle.

Background Art

[0002] In recent electric vehicles (hereinafter referred to as "EV vehicles" or "vehicles"), with the increase in the length of the battery pack, a structure for mounting the battery pack, which is a driving battery, below the floor panel has been considered (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, in the battery mounting structure of a vehicle according to the prior art such as Patent Document 1, the battery pack is configured to be supported by battery side frames so as to span between a pair of side frames of the vehicle, and the lower surface of the battery pack is exposed to the road surface side under the vehicle.

[0005] However, according to such a configuration, when traveling on a rough road or the like, the battery pack may receive an impact load (for example, interference with a rock or the like) from the road surface side under the vehicle. When receiving such an impact load, the outer wall on the lower surface side of the battery pack may be deformed.

[0006] In addition, the deformation of the battery pack needs to be avoided not only for the outer wall on the lower surface side but also for the outer wall on the side surface side in the same manner. Therefore, as a battery mounting structure, in addition to an impact load (for example, interference with a rock or the like) from the road surface side under the vehicle, when the vehicle receives an impact load from the side (for example, interference with a utility pole or the like), it is necessary to have a configuration that can protect the battery pack.

[0007] On the other hand, in recent years, due to the need to ensure a longer driving range in EV vehicles, battery packs have been getting longer, making the design of battery mounting structures increasingly difficult.

[0008] This invention has been made in view of the above-mentioned problems. Specifically, the object of this invention is to provide a battery mounting structure for an EV vehicle that can mitigate impact loads from outside the vehicle to the battery pack and protect the battery pack. [Means for solving the problem]

[0009] The main present invention that solves the aforementioned problems is: A battery mounting structure for an EV vehicle, The under panel, which serves as a mounting platform for the battery pack, is formed by arranging and connecting multiple panel components that are positioned below the floor panel of the vehicle and extend in the vehicle width direction, spanning between a pair of side members of the vehicle frame, along the vehicle's front-to-rear direction. It has a battery-equipped structure. [Effects of the Invention]

[0010] According to the battery mounting structure for EV vehicles of the present invention, it is possible to mitigate impact loads on the battery pack from outside the vehicle and protect the battery pack. [Brief explanation of the drawing]

[0011] [Figure 1] A top view of the battery mounting structure of a vehicle according to one embodiment of the present invention. [Figure 2] A side view of the battery mounting structure of a vehicle according to one embodiment of the present invention. [Figure 3] Side view showing the mounting state of the under panel to the side member of a vehicle according to one embodiment of the present invention. [Figure 4] A perspective view showing the mounting state of the under panel to the side member of a vehicle according to one embodiment of the present invention. [Figure 5]Figure showing the mounting state of the battery pack on the under panel according to an embodiment of the present invention [Figure 6] Exploded perspective view of the battery pack according to an embodiment of the present invention [Figure 7] Side view showing the attachment state of the battery pack to the under panel according to an embodiment of the present invention [Figure 8] Perspective view showing the configuration of the under panel according to an embodiment of the present invention [Figure 9] Side view showing the configuration of the under panel according to an embodiment of the present invention [Figure 10] Figure for explaining the operation of the battery mounting structure at the time of impact [Figure 11] Figure for explaining the operation of the battery mounting structure at the time of impact

Mode for Carrying Out the Invention

[0012] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the present specification and drawings, components having substantially the same function are denoted by the same reference numerals, and redundant description is omitted.

[0013] <Overall Configuration of Vehicle 1> Hereinafter, an example of the configuration of a battery mounting structure (hereinafter referred to as "battery mounting structure Ca") of an EV vehicle (hereinafter referred to as "vehicle 1") according to an embodiment of the present invention will be described.

[0014] FIG. 1 is a top view of the battery mounting structure Ca of the vehicle 1. FIG. 2 is a side view of the battery mounting structure Ca of the vehicle 1. FIG. 3 is a side view showing the attachment state of the under panel 20 to the side member 1S of the vehicle 1. FIG. 4 is a perspective view showing the attachment state of the under panel 20 to the side member 1S of the vehicle 1.

[0015] The vehicle 1 has a battery pack 10 used as a driving power source and an under panel 20 that supports the battery pack 10 from the lower side of the vehicle body.

[0016] The vehicle 1 has, for example, a vehicle frame structure similar to that of a general passenger car, and includes side members 1S extending in the longitudinal direction of the vehicle body, a cross member 1T extending in the vehicle width direction, front wheels 1WF and rear wheels 1WB attached to the side members 1S, and a floor panel 1F constituting a vehicle cabin on the side members 1S.

[0017] The side members 1S are formed of, for example, steel materials having a substantially hat-shaped cross section. The side members 1S are disposed in pairs on both the left and right sides of the vehicle body of the vehicle 1 and constitute the vehicle body frame structure. The cross member 1T is disposed so as to span between the pair of side members 1S.

[0018] However, in the vehicle 1 according to the present embodiment, in the vicinity of the middle between the front wheels 1WF and the rear wheels 1WB, there is no cross member. This is because, in order to house the long battery pack 10 under the floor panel 1F, in the battery mounting structure Ca of the vehicle 1 according to the present embodiment, the under panel 20 is configured to extend from the vicinity of the front wheels 1WF to the vicinity of the rear wheels 1WB of the vehicle 1 in the vehicle longitudinal direction. In the battery mounting structure Ca of the vehicle 1 according to the present embodiment, typically, the under panel 20 occupies a region L2 having a length of 1 / 2 or more between the position of the front wheels 1WF and the position of the rear wheels 1WB in the region L1 between the pair of side members 1S in the vehicle longitudinal direction (see FIG. 4).

[0019] The battery mounting structure Ca is constituted by an under panel 20 disposed on the lower side of the vehicle body of the floor panel 1F, and the under panel 20 functions as a mounting table for the battery pack 10. The under panel 20 is disposed so as to cover substantially the entire lower surface of the battery pack 10, and thereby, the under panel 20 functions as a shock absorber for the battery pack 10.

[0020] The under panel 20 extends in the vehicle width direction so as to span between the pair of side members 1S, and thereby, the under panel 20 also functions as a reinforcing member for reinforcing between the pair of side members 1S.

[0021] The under panel 20 is fastened and fixed to the underside of the side member 1S by bolts B1. Specifically, with the under panel 20 positioned on the underside of the side member 1S, bolts B1 are inserted from below the under panel 20 so as to connect a mounting hole (not shown) formed in the under panel 20 with a mounting hole (not shown) in the side member 1S. Then, bolts B1 are fastened with nuts coaxially welded around the mounting holes of the side member 1S, thereby fixing the under panel 20 to the side member 1S.

[0022] The floor panel 1F is mounted on a pair of side members 1S and fixed to the pair of side members 1S via rubber mounts (not shown). The floor panel 1F is mounted above the under panel 20 at a distance. That is, the battery pack 10 is housed in the space between the floor panel 1F and the under panel 20. The floor panel 1F is also mounted with a certain clearance from the battery pack 10.

[0023] <Battery Pack 10 Configuration> Figure 5 shows the battery pack 10 mounted on the under panel 20. Figure 6 is an exploded perspective view of the battery pack 10. Figure 7 is a side view showing the battery pack 10 mounted on the under panel 20.

[0024] The battery pack 10 consists of a battery body 10a and an outer case 10b that houses the battery body 10a.

[0025] For example, a high-voltage (e.g., 200V class) lithium-ion battery is used as the power source for the battery unit 10a.

[0026] The outer casing 10b is formed in the shape of a rectangular box, for example, from a metal material. The outer casing 10b consists of a tray 10ba on which the battery body 10a is placed, and a cover member 10bb that covers the battery body 10a from above.

[0027] The battery pack 10 (outer case 10b) is mounted on the under panel 20 and fixed to the under panel 20 with bolts B2. Specifically, a bracket 10R is welded to the underside of the tray 10ba of the outer case 10b, and bolts B2 (stud bolts in this case) are welded to the bracket 10R, and the under panel 20 is fixed to the bracket 10R with nuts.

[0028] <Configuration of Under Panel 20> Figure 8 is a perspective view showing the configuration of the under panel 20. Figure 9 is a side view showing the configuration of the under panel 20.

[0029] The under panel 20 functions as a mounting base for the battery pack 10 and also as an impact absorbing material that protects the battery pack 10 from impact loads from the road surface beneath the vehicle. Furthermore, the under panel 20 also functions as a reinforcing member that reinforces the space between the pair of side members 1S. In other words, the under panel 20 protects the battery pack 10 in the event of an impact load from the side of the vehicle.

[0030] The under panel 20 is constructed by arranging and connecting multiple panel components 21 (11 in this embodiment) along the vehicle's longitudinal direction, with each component extending in the vehicle's width direction so as to span between a pair of side members 1S. The number of panel components 21 constituting the under panel 20 is designed such that the length of the under panel 20 in the vehicle's longitudinal direction is longer than the length of the battery pack 10 in the vehicle's longitudinal direction.

[0031] Furthermore, each panel component 21 is formed so that its length in the vehicle width direction is longer than the length of the battery pack 10 in the vehicle width direction, and as described above, both ends of each panel component 21 in the vehicle width direction are fixed to a pair of side members 1S with bolts B1. The entire lower surface of the battery pack 10 is covered by the under panel 20 and is not exposed to the road surface under the vehicle 1.

[0032] Each panel component 21 that makes up the under panel 20 has substantially the same configuration.

[0033] Specifically, the panel component 21 has an upper plate portion 21U and a lower plate portion 21D. The panel component 21 is constructed such that the upper plate portion 21U and the lower plate portion 21D are connected to form a cavity H1 extending between them in the direction of the vehicle width. In other words, the upper plate portion 21U and the lower plate portion 21D are connected to form a closed cross-section.

[0034] More specifically, the upper plate portion 21U and the lower plate portion 21D are formed with a thickness of, for example, 4 mm to 10 mm, and the cavity portion H1 is formed with a thickness of, for example, 10 mm to 20 mm. The panel component 21 as a whole is formed with a thickness of, for example, 20 mm to 40 mm (the thickness of D1 in Figure 9). The upper plate portion 21U and the lower plate portion 21D have a plate shape and do not have any protrusions on the downward side.

[0035] The cavity H1 extends, for example, through the panel component 21 from one end to the other in the vehicle width direction. Furthermore, the cavity H1 is formed by dividing it into multiple sections, for example, along the vehicle's longitudinal direction, such that vertical walls connecting the upper plate section 21U and the lower plate section 21D are provided at various points. That is, the multiple divided cavities H1 are arranged in a line along the vehicle's longitudinal direction in a side view.

[0036] This configuration contributes to increasing the strength of the panel component 21 while reducing its weight. Specifically, this configuration makes it possible to secure a large second moment of area for the entire panel component 21 while using a thin upper plate portion 21U and a lower plate portion 21D. This ensures the bending strength of the under panel 20, reduces the amount of deformation of the under panel 20 in response to impact loads from the road surface side and the side of the vehicle, and mitigates the impact from the under panel 20 to the battery pack 10. In addition, this allows the under panel 20 to function effectively as a reinforcing member that reinforces the space between the pair of side members 1S.

[0037] Furthermore, with this configuration, even if there is an impact load from the road surface beneath the vehicle (for example, interference with a rock), the presence of the cavity H1 causes only the lower plate portion 21D to deform, suppressing the deformation of the upper plate portion 21U. In other words, this allows the impact energy from the road surface beneath the vehicle to be absorbed by the under panel 20.

[0038] The panel component 21 has insertion protrusions 21a or gripping recesses 21b at both ends in the vehicle's front-rear direction. Adjacent panel components 21 constituting the under panel 20 are welded together with the insertion protrusions 21a of one panel component 21 fitted together with the gripping recesses 21b of the other panel component 21. The insertion protrusions 21a are thin-walled extensions that extend from the main body of the panel component 21 in the vehicle's front-rear direction, and the gripping recesses 21b are openings that extend from the main body of the panel component 21 in the vehicle's front-rear direction.

[0039] Here, the vertical thickness of the front-rear end of the panel component 21 (i.e., the insertion projection 21a or the gripping recess 21b) is thinner than the vertical thickness of the central part 21c of the panel component 21. As a result, when the battery pack 10 is placed on the under panel 20, a partial space is formed between the battery pack 10 and the under panel 20. This space functions as a buffer when the under panel 20 deforms due to impact loads from the road surface beneath the vehicle, suppressing the transmission of impact energy from the road surface beneath the vehicle to the battery pack 10. This configuration also corresponds to the uneven structure on the underside of the battery pack 10.

[0040] The panel component 21 is formed from, for example, an aluminum material that is lightweight and easy to ensure high strength. More specifically, the panel component 21 is formed from, for example, an aluminum extruded material, and the upper plate portion 21U and the lower plate portion 21D are integrally molded. Since aluminum extruded material can be molded into complex shapes, it is suitable for manufacturing components having complex shapes such as the panel component 21 according to this embodiment.

[0041] In the battery mounting structure Ca according to this embodiment, the under panel 20 is constructed by connecting multiple panel components 21 for the following reasons.

[0042] First, the under panel 20 needs to be positioned to cover almost the entire underside of the long battery pack 10, and also function as a reinforcing member that reinforces the space between the pair of side members 1S. Therefore, the under panel 20 needs to be large enough to extend from the front wheel 1WF to the vicinity of the rear wheel 1WB in the longitudinal direction of the vehicle 1. Manufacturing an under panel 20 of such size from a single panel component 21 is practically very difficult due to limitations in aluminum extrusion manufacturing equipment, etc. From this perspective, a method of constructing the under panel 20 by connecting multiple panel components 21 is adopted.

[0043] In addition, by adopting a method of constructing the under panel 20 by connecting multiple panel components 21, the length of the under panel 20 in the vehicle's front-to-rear direction can be easily adjusted by adjusting the number of panels 21. This makes it possible to reuse panel components 21 with the same configuration for vehicles of various wheelbases. Furthermore, by preparing multiple types of panel components 21 with different lengths in the vehicle's width direction, it is also possible to adjust the length of each part of the under panel 20 in the vehicle's width direction.

[0044] <Regarding the effect of the Ca component in the battery mounting structure during impact> Next, with reference to Figures 10 and 11, the function of the battery mounting structure Ca during an impact will be explained. Here, as shown in Figure 10, the function will be explained in the case where, for example, a road surface obstruction N such as a protruding stone interferes with the under panel 20 when the vehicle is driving on rough roads, and as shown in Figure 11, the function will be explained in the case where the vehicle 1 collides sideways with a cylindrical pole P that extends vertically.

[0045] When a road surface object N interferes with the under panel 20, first, due to the presence of the cavity H1, only the lower plate portion 21D of the under panel 20 deforms, and the deformation of the upper plate portion 21U is suppressed. As a result, the impact energy from the road surface beneath the vehicle to the battery pack 10 is absorbed by the under panel 20.

[0046] Here, if the impact load on the under panel 20 from the road surface obstruction N is large, the under panel 20 as a whole (upper plate portion 21U and lower plate portion 21D) will attempt to deform by curving upward. However, the cavity H1 in the under panel 20 is formed by dividing it so that vertical walls connecting the upper plate portion 21U and the lower plate portion 21D are placed at various points. Therefore, the bending strength of the under panel 20 is relatively strong, and the amount of deformation that causes the under panel 20 to curve upward is small. As a result, the impact energy from the road surface beneath the vehicle to the battery pack 10 is absorbed by the under panel 20.

[0047] In other words, the presence of the under panel 20 protects the battery pack 10 from the load applied when road surface obstructions N interfere with the underside of the vehicle 1.

[0048] On the other hand, as shown in Figure 11, if a vehicle collides with pole P from the side, for example, a collision load is applied to the left side member 1S. Therefore, the left side member 1S moves while undergoing plastic deformation inward in the vehicle width direction, and transmits a portion of the applied collision load to the under panel 20.

[0049] Here, since the under panel 20 is positioned to span between the pair of side members 1S, the impact load applied to the left side member 1S is transmitted to the right side member 1S via the under panel 20. As a result, the impact energy applied to the left side member 1S is also distributed to the right side member 1S. This suppresses the deformation of the left side member 1S due to the impact load. In other words, this makes it possible to mitigate the impact load acting on the side of the battery pack 10 through the deformation of the left side member 1S.

[0050] The dotted line α1 in Figure 11 shows the deformation of the left side member 1S when the under panel 20 is not disposed between the pair of side members 1S. On the other hand, the dotted line α2 shows the deformation of the left side member 1S when the under panel 20 is disposed between the pair of side members 1S.

[0051] Furthermore, even in this case, since the bending strength of the under panel 20 is relatively strong, the amount of deformation of the under panel 20 is relatively small, and the impact energy input to the left side member 1S is widely distributed to the right side member 1S.

[0052] In other words, the presence of the under panel 20 protects the battery pack 10 from the impact load applied when a vehicle collides with pole P from the side.

[0053] [effect] As described above, in this embodiment, As a battery mounting structure for EV vehicles, The under panel, which serves as a mounting platform for the battery pack, is formed by arranging and connecting multiple panel components that are positioned below the floor panel of the vehicle and extend in the vehicle width direction, spanning between a pair of side members of the vehicle frame, along the vehicle's front-to-rear direction. The battery mounting structure was disclosed.

[0054] According to the battery mounting structure of the EV vehicle of this embodiment, it is possible to mitigate impact loads on the battery pack from outside the vehicle and protect the battery pack. Furthermore, this configuration also makes it possible to prevent damage to the battery from fire from below.

[0055] In addition, since the under panel according to this embodiment is constructed by connecting multiple panel components, it can be made large enough to accommodate a long battery pack. Furthermore, with this configuration, the length of the under panel in the vehicle's longitudinal direction can be adjusted by adjusting the number of panel components, making it applicable to vehicles with various wheelbases.

[0056] Although specific examples of the present invention have been described in detail above, these are merely illustrative and do not limit the scope of the claims. The technologies described in the claims include various modifications and changes to the specific examples illustrated above. [Industrial applicability]

[0057] According to the battery mounting structure for EV vehicles of the present invention, it is possible to mitigate impact loads on the battery pack from outside the vehicle and protect the battery pack. [Explanation of Symbols]

[0058] 1 vehicle Ca battery-equipped structure 1F Floor Panel 1S Side Member 1T Crossmember 1WB rear wheel 1WF Front Wheel 10 Battery Packs 20 Under Panel 21 Panel parts

Claims

1. A battery mounting structure for an EV vehicle, The under panel, which serves as a mounting platform for the battery pack, is constructed by arranging and connecting multiple panel components that are positioned below the floor panel of the vehicle and extend in the vehicle width direction, spanning between a pair of side members of the vehicle frame, along the vehicle's front-to-rear direction. Battery-integrated structure.

2. The under panel occupies an area in the vehicle's longitudinal direction that is at least half the length between the front and rear wheel positions of the vehicle, within the region between the pair of side members. The battery mounting structure according to claim 1.

3. In the area where the under panel is installed, there is no cross member that spans between the pair of side members. The battery mounting structure according to claim 1.

4. The panel component has an upper plate portion and a lower plate portion. The upper plate portion and the lower plate portion are connected such that a cavity is formed between them, extending in the direction of the vehicle width. The battery mounting structure according to claim 1.

5. The aforementioned cavity is formed by dividing it into multiple sections such that vertical walls connecting the upper side plate and the lower side plate are provided at various points along the vehicle's longitudinal direction. The battery mounting structure according to claim 4.

6. The panel component has insertion protrusions or gripping recesses at both ends in the vehicle's front-rear direction, The adjacent panel components constituting the under panel are welded together with the insertion projection of one panel component fitted into the gripping recess of the other panel component. The battery mounting structure according to claim 1.

7. The vertical thickness of the panel component at its front-to-rear end in the vehicle's longitudinal direction is thinner than the vertical thickness at the center of the panel component. The battery mounting structure according to claim 6.

8. The aforementioned panel component is integrally molded from aluminum extruded material. The battery mounting structure according to claim 1.

9. The panel component is bolted to the lower surface of the pair of side members on both sides in the vehicle width direction. The battery mounting structure according to claim 1.

10. The under panel is arranged to cover substantially the entire lower surface of the battery pack. The battery mounting structure according to claim 1.

11. The battery pack is mounted on the under panel and positioned in the area between the pair of side members. The battery mounting structure according to claim 1.

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