Battery case

Abstract

This battery case offers advantages in protecting the battery pack without sacrificing space in the vehicle's interior. [Solution] Multiple protruding sections 30 are continuously formed at intervals in the vehicle width direction, each consisting of multiple pairs of inclined surfaces 24 and multiple lower surfaces 26 connecting the lower ends of the pairs of inclined surfaces 24 on the battery case 12. When an object falling from the road surface collides with a protruding section 30, the load applied to the lower surface 26 of the protruding section 30 is transmitted to the upper surface 28 via the pairs of inclined surfaces 24. Thus, the load is distributed by the pairs of inclined surfaces 24 into a vertical load and a horizontal (vehicle width direction) load, and transmitted to the battery case 12.

Description

[Technical Field]

[0001] The present invention relates to a battery case. [Background Art]

[0002] Electric vehicles such as electric vehicles and hybrid vehicles that use a motor as a driving source are equipped with a battery pack that supplies power to the motor. A battery pack includes a plurality of battery modules, an electrical component unit for controlling these battery modules, and a battery case that accommodates these battery modules and the electrical component unit, and is disposed below the floor panel of a vehicle. The bottom surface of the case is covered with an undercover to protect the battery pack from falling objects such as stones on the road surface (see Patent Document 1). [Prior Art Documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2024-140735 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] By the way, when driving on rough roads such as gravel roads, it is important from the perspective of protecting the battery pack to ensure as large a ground clearance of the battery pack and the battery case as possible. On the other hand, increasing the ground clearance of the battery pack and the battery case will restrict the space of the vehicle cabin in the vertical direction. Therefore, how to achieve both protection of the battery pack and securing of vehicle cabin space has become a problem. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a battery case that is advantageous for protecting a battery pack by the battery case without sacrificing the space of the vehicle cabin. [Means for solving the problem]

[0005] To achieve the above objective, one embodiment of the present invention is a battery case that covers the bottom surface of a battery pack located at the bottom of a vehicle, wherein the battery case has a protruding portion that extends in the longitudinal direction of the vehicle and has a shape when cut by a vertical plane passing through the vehicle width direction such that the shapes face each other in the vehicle width direction and are inclined in a direction that moves away from each other as it goes upward, and a lower surface that connects the lower ends of the inclined portions, wherein a plurality of the protruding portions are formed continuously at intervals in the vehicle width direction via an upper surface that connects the upper ends of the inclined portions. Furthermore, one embodiment of the present invention is characterized in that the spacing between the plurality of protrusions in the vehicle width direction is smaller on the outer side in the vehicle width direction than on the center in the vehicle width direction. Furthermore, one embodiment of the present invention is characterized in that, on both sides in the vehicle width direction, the width of the protruding portion along the vehicle width direction is formed to be small, and in the central part in the vehicle width direction, the width of the protruding portion along the vehicle width direction is formed to be large. Furthermore, one embodiment of the present invention is characterized in that the plurality of protruding portions are inclined and extend toward the center in the vehicle width direction as they move toward the rear of the vehicle. Furthermore, in one embodiment of the present invention, the battery case is composed of a front case located in front of the vehicle and a rear case located behind the front case, and the inclined surface, the bottom surface, and the top surface of the front end of the rear case are joined to the inclined surface, the bottom surface, and the top surface of the rear end of the front case, respectively. [Effects of the Invention]

[0006] According to one embodiment of the present invention, multiple protruding sections, each composed of a plurality of pairs of inclined surfaces and a plurality of lower surfaces connecting the lower ends of the pairs of inclined surfaces, are continuously formed at intervals in the vehicle width direction. Therefore, when an object falling from the road surface collides with a protruding section, the load is transmitted from the lower surface to the upper surface via the pair of inclined surfaces. As a result, the load is distributed into vertical and horizontal loads and transmitted to the battery case, so that the collision energy is efficiently absorbed by the battery case. Therefore, it is possible to reliably protect the battery pack from falling objects without having to significantly increase the ground clearance of the battery case. In other words, it is extremely advantageous in protecting the battery pack with a battery case without sacrificing space in the vehicle's interior. Furthermore, forming the spacing between multiple protrusions in the vehicle width direction so that the spacing is smaller on the outer edges in the vehicle width direction than at the center in the vehicle width direction is advantageous in ensuring the strength and durability of the battery case against impacts from falling objects, as well as in reducing the weight of the battery case. Furthermore, if the width of the raised section along the vehicle width direction is small on both sides in the vehicle width direction, and large in the center in the vehicle width direction, it is advantageous in ensuring the strength and durability of the battery case against impacts from falling objects, as well as in reducing the weight of the battery case. Furthermore, if multiple protrusions extend in a sloping manner toward the center in the vehicle width direction as they move toward the rear of the vehicle, the airflow collected in the center in the vehicle width direction is smoothly guided toward the rear of the vehicle, avoiding the turbulent, swirling airflow on both sides in the vehicle width direction, which is advantageous in ensuring the aerodynamic performance of the vehicle. Furthermore, by joining the inclined surface, bottom surface, and top surface of the rear end of the front battery case to the inclined surface, bottom surface, and top surface of the rear end of the front battery case, the resistance received by the airflow during driving can be minimized, which is advantageous in ensuring the aerodynamic performance of the vehicle. [Brief explanation of the drawing]

[0007] [Figure 1]This is a front view of the lower part of a vehicle to which the battery case according to the first embodiment is applied, as seen from the front of the vehicle. [Figure 2] This is a magnified section of Figure 1. [Figure 3] This is a bottom view of a vehicle to which the battery case according to the first embodiment is applied. [Figure 4] This is a cross-sectional view along line AA in Figure 3. [Figure 5] This is a cross-sectional view of a battery pack fitted with a battery case according to the second embodiment, and corresponds to the cross-sectional view along line AA in Figure 3. [Figure 6] This is a cross-sectional view of a battery pack fitted with a battery case according to the third embodiment, and corresponds to the cross-sectional view along line AA in Figure 3. [Figure 7] This is a bottom view of a vehicle to which the battery case according to the fourth embodiment is applied. [Modes for carrying out the invention]

[0008] (First Embodiment) Hereinafter, embodiments of the present invention will be described with reference to Figures 1 to 4. In the following diagrams, the symbol FR indicates the front of the vehicle, the symbol UP indicates the top of the vehicle, and the symbol HL indicates the width direction of the vehicle. As shown in Figure 1, the battery pack 14 is mounted on a vehicle 10 that is an electric vehicle driven solely by a motor, or a hybrid vehicle, or a plug-in hybrid vehicle that is driven by a motor and can be externally charged or powered, and supplies power to the motor. The battery case 12 in this embodiment protects the battery pack 14.

[0009] The battery pack 14, although not shown, is composed of a plurality of battery modules, an electrical unit that controls the battery modules, and a case 16 which consists of a tray 16A that houses the battery modules and the electrical unit, and a cover 16B that covers the top of the tray 16A. The tray 16A includes an unillustrated rectangular frame-shaped tray frame, and tray cross members 18 (Fig. 3) for increasing the rigidity of the tray 16A are provided at a plurality of locations of the tray 16A spaced apart in the vehicle front-rear direction of the tray frame. As shown in Fig. 3, when viewed in a plan view, the outline of the battery pack 14 is largely secured between the front wheels 20 and the rear wheels 22 in the vehicle front-rear direction and the vehicle width direction. As shown in Fig. 1, although not illustrated, the front and rear portions of the battery pack 14 and both side portions in the vehicle width direction are attached to vehicle body frame members such as side sills below the floor panel, and the battery pack 14 is arranged at the lower part of the vehicle 10.

[0010] As shown in Fig. 1 and Fig. 3, the battery case 12 is a member that covers the bottom surface of the battery pack 14 and protects the battery pack 14 from falling objects on the road surface and the like. The battery case 12 may be made of steel or may be made of synthetic resin. As shown in Fig. 2, the battery case 12 has a protruding strip portion 30 that is configured by a pair of inclined surfaces 24 that extend in the vehicle front-rear direction, and whose cross-sections cut along a vertical plane passing through the vehicle width direction face each other in the vehicle width direction and are inclined in a direction away from each other as going upward, and a lower surface 26 connecting the lower ends of the inclined surfaces 24. A plurality of protruding strip portions 30 are continuously formed at intervals in the vehicle width direction via an upper surface 28 connecting the upper ends of the inclined surfaces 24.

[0011] As shown in Fig. 3, the battery case 12 is configured by a front case 12A located at the front of the vehicle, and a rear case 12B located behind the front case 12A in the vehicle. At the central portion of the tray 16A in the vehicle front-rear direction, the inclined surface 24, lower surface 26, and upper surface 28 at the front end of the rear case 12B are joined onto the inclined surface 24, lower surface 26, and upper surface 28 at the rear end of the front case 12A.

[0012] As shown in Figures 3 and 4, at a plurality of locations spaced apart in the vehicle front-rear direction of the battery case 12, and at a plurality of locations on the upper surface 28 spaced apart in the vehicle width direction, the battery case 12 is attached from below to the bottom surface 1402 of the battery pack 14 constituted by a tray frame, a tray cross member 18, and the like using bolts B. Note that a cap made of rubber or synthetic resin (not shown) is attached to an opening formed by a pair of inclined surfaces 24 and the lower surface 26 at the vehicle front end of each protruding strip 30, and intrusion of dust, foreign matter, rainwater and the like into the protruding strips 30 during traveling is prevented.

[0013] Next, the functions and effects will be described. According to the present embodiment, a plurality of protruding strips 30 each constituted by a plurality of pairs of inclined surfaces 24 of the battery case 12 and a plurality of lower surfaces 26 connecting the lower ends of the pair of inclined surfaces 24 are formed continuously at intervals in the vehicle width direction. Therefore, when a falling object on the road surface collides with the protruding strip 30, the load input to the lower surface 26 of the protruding strip 30 is transmitted to the upper surface 28 via the pair of inclined surfaces 24. Accordingly, the load is dispersed into a vertical load and a load in the horizontal direction (vehicle width direction) by the pair of inclined surfaces 24, and then transmitted to the battery case 12. Specifically, when the pair of inclined surfaces 24 are deformed so as to be crushed upward, the load is dispersed into the vertical load and the horizontal load by the inclined surfaces 24, so collision energy is efficiently absorbed by the battery case 12. Therefore, the battery pack 14 can be reliably protected from falling objects without ensuring a large ground clearance of the battery case 12. In other words, this configuration is extremely advantageous for protecting the battery pack 14 by the battery case 12 without sacrificing the space of the vehicle cabin.

[0014] Note that the inclination angle formed by the pair of inclined surfaces 24 and the upper surface 28 can be set in a range greater than 0 degrees and smaller than 90 degrees, and 45 degrees is the most preferable for the inclination angle. This is because a 45-degree inclination angle allows the vertical and horizontal loads on the inclined surface 24 to be distributed equally, which is advantageous for absorbing collision energy most efficiently in the battery case 12.

[0015] In this embodiment, the battery case 12 is composed of a front case 12A located at the front of the vehicle and a rear case 12B located behind the front case 12A. The inclined surface 24, lower surface 26, and upper surface 28 of the front end of the rear case 12B are joined to the inclined surface 24, lower surface 26, and upper surface 28 of the rear end of the front case 12A, respectively. Therefore, the airflow along the battery case 12 can minimize the resistance it experiences as it passes through the boundary between the rear end of the front case 12A and the front end of the rear case 12B, which is advantageous in ensuring the aerodynamic performance of the vehicle 10.

[0016] (Second Embodiment) Next, a second embodiment will be described with reference to Figure 5. In the following description of the embodiments, the same reference numerals are used for parts and components as in the first embodiment, and their descriptions are omitted or simplified. The description will focus on the parts that differ from the first embodiment. The inventors have discovered that during driving, falling objects do not collide evenly with the battery case 12, but rather collide more frequently with the areas on both sides of the battery case 12 in the vehicle width direction than with the center of the battery case 12 in the vehicle width direction. Therefore, in the first embodiment, all the protruding ridges 30 were provided at equal intervals in the vehicle width direction, whereas in the second embodiment, the spacing between the multiple protruding ridges 30 in the vehicle width direction was formed such that the distance to the outer edges in the vehicle width direction was smaller than the distance to the center in the vehicle width direction. Here, the spacing between the protruding sections 30 in the vehicle width direction is the spacing D between the upper ends of a pair of opposing inclined surfaces 24 of adjacent protruding sections 30.

[0017] According to the second embodiment, the spacing between the multiple protrusions 30 on both sides of the battery case 12 in the vehicle width direction, which are prone to impact from falling objects, is made small. This allows for a large number of protrusions 30 per unit area on both sides of the battery case 12 in the vehicle width direction, which is advantageous in ensuring the strength and durability of the battery case 12 against impact from falling objects. Furthermore, by making the spacing between the multiple protrusions 30 in the center of the battery case 12 in the vehicle width direction larger, the number of protrusions 30 per unit area in the center of the vehicle width direction can be suppressed, which is advantageous in reducing the weight of the battery case 12.

[0018] (Third embodiment) Next, a third embodiment will be described with reference to Figure 6. As described above, the inventors have discovered that during driving, falling objects do not collide evenly with the battery case 12, but rather that more falling objects collide with the areas on both sides of the battery case 12 in the vehicle width direction than with the center of the battery case 12 in the vehicle width direction. Therefore, in the first embodiment, the width of all the protruding sections 30 along the vehicle width direction was uniform, whereas in the third embodiment, the width of the protruding sections 30 along the vehicle width direction was formed to be smaller on both sides in the vehicle width direction, and larger in the center of the vehicle width direction. Here, the width W of the protruding portion 30 along the vehicle width direction is the dimension between the upper ends of the pair of inclined surfaces 24 that form the protruding portion 30.

[0019] According to the third embodiment, the width of the protrusions 30 on both sides of the battery case 12 in the vehicle width direction, which are prone to impact from falling objects, is made small. This allows for a larger number of protrusions 30 per unit area on both sides of the battery case 12 in the vehicle width direction, which is advantageous in ensuring the strength and durability of the battery case 12 against impact from falling objects. Furthermore, by making the width of the protruding portion 30 in the vehicle width direction at the center of the battery case 12 larger, the number of protruding portions 30 per unit area at the center of the vehicle width direction can be reduced, which is advantageous in reducing the weight of the battery case 12.

[0020] (Fourth embodiment) Next, a fourth embodiment will be described with reference to Figure 7. In the first to third embodiments, the case in which all the protruding sections 30 extend in the longitudinal direction of the vehicle along their entire length was described. However, in the fourth embodiment, the remaining protruding sections 30, excluding the protruding section 30 located in the center in the vehicle width direction, are inclined to collect the airflow at the rear of the vehicle towards the center in the vehicle width direction. In other words, the rear portions of the multiple protrusions 30 located on both sides in the vehicle width direction are formed as inclined protrusions 3002 that gradually slope towards the center in the vehicle width direction as they move towards the rear of the vehicle. In other words, the multiple protruding sections 30 extend in an inclined manner toward the center in the width direction of the vehicle as they move toward the rear of the vehicle. When the vehicle is in motion, a turbulent, swirling airflow T is likely to be generated near the pair of rear wheels 22. According to the fourth embodiment, the inclined protrusions 3002 of the remaining protrusions 30, excluding the protrusion 30 located in the center in the vehicle width direction, cause the airflow to be collected at the rear of the vehicle and towards the center in the vehicle width direction. In other words, the multiple convex sections 30 that extend inclined toward the center in the width direction as they move toward the rear of the vehicle concentrate the airflow toward the center in the width direction at the rear of the vehicle. Therefore, the airflow F, which is concentrated in the center in the width direction of the vehicle, is guided smoothly to the rear of the vehicle, avoiding the turbulent airflow T on both sides in the width direction of the vehicle, thus providing an advantage in ensuring the aerodynamic performance of the vehicle 10. [Explanation of Symbols]

[0021] 10 vehicles 12 Battery Cases 12A Front Case 12B Rear Case 14 Battery Packs 1402 Bottom of the battery pack 16 cases 16A Tray 16B Cover 18 Tray Cross Member 20 Front Wheel 22 Rear wheels 24 Slope 26 Bottom side 28 Top 30 raised section 3002 Inclined convex section B bolt D Spacing between the protruding sections 30 in the vehicle width direction W width of the protruding section 30 along the vehicle width direction

Claims

1. A battery case that covers the bottom surface of a battery pack located at the bottom of a vehicle, The battery case has a convex portion that extends in the longitudinal direction of the vehicle and has a shape when cut by a vertical plane passing through the vehicle width direction, which is inclined so that it faces each other in the vehicle width direction and moves away from each other as it goes upward, and a lower surface that connects the lower ends of the inclined surfaces. The aforementioned protruding portions are formed continuously in multiple locations at intervals in the vehicle width direction via an upper surface that connects the upper ends of the inclined surfaces. A battery case characterized by the following features.

2. The spacing between the multiple protrusions in the vehicle width direction is formed such that the distance to the outer edges in the vehicle width direction is smaller than the distance to the center in the vehicle width direction. The battery case according to claim 1, characterized in that it is a battery case.

3. On both sides in the vehicle width direction, the width of the protruding portion along the vehicle width direction is formed to be small. In the central part in the vehicle width direction, the width of the protruding portion along the vehicle width direction is formed to be large. The battery case according to claim 1, characterized in that it is a battery case.

4. The multiple aforementioned protrusions extend in an inclination toward the center in the vehicle width direction as they move toward the rear of the vehicle. The battery case according to claim 1, characterized in that it is a battery case.

5. The battery case consists of a front case located at the front of the vehicle and a rear case located behind the front case. The inclined surface, the lower surface, and the upper surface of the rear end of the front case are joined to the inclined surface, the lower surface, and the upper surface of the rear end of the front case, respectively. The battery case according to claim 1, characterized in that it is a battery case.

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