Battery pack protection structure

Abstract

To provide a protection structure which achieves higher protection effect against an external impact when a battery pack is mounted under a floor of a vehicle.SOLUTION: A protective structure for a battery pack mounted under a floor of a vehicle, includes: a case body accommodating the battery pack; and an under member arranged below the case body. The under member includes: a plurality of panels. The adjacent panels are connected by multiple fitting recesses and fitting pieces fitting with each other.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a protection structure when a battery pack is mounted as a drive source in an electric vehicle, a hybrid vehicle, etc., and particularly relates to a protection structure when the battery pack is mounted below the floor of a vehicle.

Background Art

[0002] A battery pack composed of secondary batteries is also referred to as a battery module, a battery module, etc., and is mounted as a drive source in an electric vehicle, a hybrid vehicle, etc. In the structure for mounting a battery pack on a vehicle, in addition to the structure for mounting in the vehicle body space such as the rear side or the front side of the vehicle, in recent years, a structure for mounting below the floor of the vehicle body has also been studied. When mounting a battery pack below the floor of a vehicle, for example, it is necessary to protect the battery from a load applied upward from below due to road surface unevenness, flying stones during driving, etc. As disclosed in Patent Documents 1 and 2, the inventors have developed a protection structure for a battery pack in which a plurality of panel members connected by fitting a pair of mutually adjacent convex portions and concave portions (one set of fitting) are disposed below the battery pack.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a protection structure having a higher protection effect against external impacts when mounting a battery pack below the floor of a vehicle.

Means for Solving the Problems

[0005] The battery pack protection structure according to the present invention is a battery pack protection structure mounted under the floor of a vehicle, comprising a case body housing the battery pack and an under member disposed below the case body, wherein the under member consists of a plurality of panels, and adjacent panels are connected by the fitting of a plurality of fitting recesses and fitting pieces.

[0006] Here, the fitting of multiple fitting recesses and fitting pieces means that, when the fitting of a fitting piece to one fitting recess is considered as one set, there are at least two or more fitting parts. By forming multiple fitting sections consisting of fitting recesses and fitting pieces to connect adjacent panels among the multiple panels that make up the under member, the rigidity of the connecting section can be increased compared to conventional methods. When a load is applied to the under member from below, the stress can be efficiently distributed to adjacent panels through multiple fitting parts, resulting in high overall strength for the under member. This eliminates the need for welding to ensure strength, as was done in the past, thus reducing welding time and costs. The case containing the battery pack is a rechargeable, so-called secondary battery and its control equipment, and there are no particular restrictions on its structure.

[0007] In the present invention, among the plurality of fitting recesses and fitting pieces, a pair of fitting recesses and fitting pieces may have one locking portion and the other being locked portion, and the locking portion and the locked portion may lock together with each other or lock together when a load is applied from below to above the under member. A pair of locking parts and locked parts may be pre-locked to the extent that they can be fitted and assembled together, but if adjacent panels lock together at their locking and locked parts when a load is applied to the under member, the panels will not separate even when a load is applied, and the strength of the connecting part will be increased. Therefore, the locking portion and the locked portion may have a predetermined clearance from each other to facilitate assembly. Furthermore, it is preferable that the connecting portion of the adjacent panels has at least two sets of a pair of fitting recesses and fitting pieces that are capable of being locked, each having a locking portion and a locked portion. In this way, no matter which panel constituting the under member is subjected to a load, the locking portion and the locked portion provided at any of the fitting parts will engage with each other, making it easier to ensure the strength of the connecting part. Each panel constituting the underbody member may have a hollow cross-sectional shape, for example, made from an extruded aluminum alloy. This allows the deformation of the hollow section to absorb external input loads, thus achieving both improved protective strength and reduced weight.

[0008] In the present invention, in the connecting portion of adjacent panels, one panel may have a plurality of fitting recesses at different positions at the bottom, and the other panel may have a plurality of fitting pieces at different positions at the apex corresponding to the plurality of fitting recesses. If multiple fitting recesses provided on one panel have different depths to the bottom of the recesses, it is preferable that the other panel be provided with a fitting piece having its apex at a position corresponding to this bottom. For example, if, of two fitting recesses provided in one panel, the bottom of the lower second recess is deeper than the upper first recess, the fitting piece that engages with the second recess is located approximately below the bottom of the first recess. This allows the load from this fitting piece to be received by the bottom of the first recess as well, resulting in superior strength against impact. [Effects of the Invention]

[0009] According to the battery pack protection structure of the present invention, the under member disposed below the battery pack is composed of multiple panels, and adjacent panels are connected by the fitting of multiple fitting recesses and fitting pieces. As a result, the rigidity of the connecting parts is higher than in conventional structures, and stress can be efficiently distributed to adjacent panels through multiple fitting parts, thus providing a high level of protection for the battery pack against external impacts. [Brief explanation of the drawing]

[0010] [Figure 1] An example of a protective structure for a battery pack according to the present invention is shown. [Figure 2] The connecting section between adjacent panels is shown in a magnified view. [Figure 3] Figure 2 shows an example of the condition when a load is applied from the bottom upwards to one of the panels. [Figure 4] Figure 2 shows an example of the condition when a load is applied from the bottom upwards to the other panel. [Modes for carrying out the invention]

[0011] An example of a protective structure for a battery pack mounted in a vehicle according to the present invention will be described below with reference to the figures. Figure 1 shows a cross-sectional view of the vehicle-mounted portion of the battery pack. The battery pack protection structure comprises an under member 1 consisting of multiple panels and a case body 2 attached to the upper side of this under member, with multiple battery packs 3, which serve as the power source for the vehicle, housed inside the case body 2. There are no particular restrictions on the structure of the case, but if it is mounted on the underside of the vehicle's floor line, it is preferable that it be designed to prevent water from entering from the outside. In this embodiment, the case body 2 has a flange portion 5a of an L-shaped cross-section side wall portion 5 fixed to a plate-shaped lower portion 4, and the side wall portion 5 is erected in a frame-like manner relative to the lower portion 4. Of the lower part 4 of the case body, the mounting portion 4a located opposite to or outside the flange portion 5a, as shown in Figure 1, is directly fixed to the under member 1. Furthermore, the case body may be indirectly fixed to the under member, or the intermediate panel of the under member 1 (for example, the first panel 10, etc.) and the lower part 4 of the case body may be fixed to each other.

[0012] The under member 1 consists of a pair of fastening panels 30 located at both ends and a plurality of intermediate panels connecting them, and each panel is an example of being made from an extruded aluminum alloy. There is no particular limitation on the number of intermediate panels. Hereinafter, adjacent intermediate panels will be described as the first panel 10 and the second panel 20, but one of the adjacent panels may be a fastening panel. The first panel 10 and the second panel 20 each have a plurality of ribs connecting between the upper surface portions 11, 21 and the lower surface portions 12, 22, and a plurality of hollow portions are formed therebetween. The fastening panel 30 has a fastening portion 32 extending upward and outward from the continuous portion 31 connected to the intermediate panel. In this embodiment, the attachment portion 4a at the lower part of the case body 2 is attached to the fastening portion 32, and the fastening portion 32 is fastened and fixed to the vehicle body frame 6 using a fastening member 7.

[0013] In FIG. 2, an enlarged view of the connecting portion between the first panel 10 and the second panel 20 is shown. Adjacent panels are connected by fitting a plurality of fitting recesses and fitting pieces. If the fitting recess is a recess composed of a bottom portion and a pair of side portions erected on both sides thereof, the fitting piece is inserted between the pair of side portions, and a fitting portion is formed by the pair of fitting recesses and the fitting piece. In addition to the side portions of the fitting recess and the fitting piece being able to abut against each other, the apex of the convex fitting piece may be able to abut against the bottom portion of the fitting recess for each of the plurality of fitting portions. Hereinafter, specifically, the fitting connection between the first panel and the second panel will be described. The first panel 10 has a first rib 13 as a rib on the end side connecting between the upper surface portion 11 and the lower surface portion 12. The first rib 13 is composed of an intermediate portion 14 parallel to the upper surface portion and the lower surface portion, and a first bottom portion 15 and a second bottom portion 16 connecting the intermediate portion to the upper surface portion 11 and the lower surface portion 12 vertically, respectively. In this embodiment, at one end of the first panel, a first recess 17 having the tip side and the intermediate portion 14 of the upper surface portion 11 as a pair of side portions and the first bottom portion 15 as the bottom portion, and the tip side and the intermediate portion 14 of the lower surface portion 12 as a pair of side portions and the second bottom portion 16 as the bottom portion, and in addition to these two fitting recesses, the tip side of the intermediate portion 14 has one fitting piece that becomes a third convex portion 14a. On the other hand, the second panel 20 has a second rib 23 as an end rib connecting the upper portion 21 and the lower portion 22, and this second rib faces the first rib of the first panel. The second rib 23 has a connecting portion 26 that vertically connects the respective tip ends of the upper portion 21 and the lower portion 22, and a first convex portion 24 and a second convex portion 25 that protrude from the connecting portion 26 toward the first rib 13 of the first panel. The two fitting pieces (first protrusion 24, second protrusion 25) are inserted into the two fitting recesses (first recess 17, second recess 18) of the first panel, respectively, with the upper surfaces 11, 21 of each panel in an approximately horizontal position, thereby forming two fitting portions. The end of the second panel adjacent to the first panel further has a third recess 27 with a first protrusion 24 and a second protrusion 25 as a pair of sides and a connecting portion 26 as the bottom, so that the third protrusion 14a of the first panel fits into this third recess. This embodiment shows an example with three interlocking parts, but it is sufficient if adjacent panels have two or more interlocking parts to be connected. For example, if the first rib is further provided with an intermediate section and a bottom section connecting the intermediate sections vertically, a new recess consisting of the intermediate section and the bottom section can be formed, and a corresponding protrusion can be provided on the second rib to increase the number of fitting sections. In Figure 2, a gap is provided between the recess and the protrusion. This is to illustrate how adjacent panels can be easily fitted together horizontally; this gap is unnecessary if assembly is possible.

[0014] In this embodiment, of the two fitting recesses provided in the first panel, the first recess 17 has a shallower bottom position than the second recess 18. In other words, the first bottom portion 15 is located closer to the second panel than the second bottom portion 16. In response to this, of the two fitting pieces provided on the second panel, the apex of the second protrusion 25 is positioned so that it protrudes more towards the first panel than the first protrusion 24. In this manner, at the connecting portion of adjacent panels, the bottom positions of the multiple recesses provided on one panel may differ, and correspondingly, the vertex positions of the multiple protrusions provided on the other panel may also differ. As a result, for example, when a load is applied upward to the lower surface 22 of the second panel as shown in Figure 3, the load can be received at the first bottom 15 via the intermediate portion 14 of the first panel from the second protrusion 25. In other words, because the bottoms of the multiple recesses are in different positions, an overlapping portion d is created between the vertex 25b of the second protrusion and the first bottom 15, which is the bottom of the first recess.

[0015] When a load is applied from below the under member upwards, the pair of fitting recesses and fitting pieces lock together in the left-right direction, thereby increasing the rigidity of the panel connection. Therefore, in this embodiment, a locking portion and a locked portion are provided so that the first recess and the first protrusion, and the second recess and the second protrusion, can lock into each other. Furthermore, the third recess and the third protrusion may have a locking portion and a locked portion that can lock into each other. In this embodiment, as shown in Figure 3 for example, a connecting portion 26 suspended from the tip of the lower surface portion 22 of the second panel is connected to the tip of the upper surface portion 21 via a substantially L-shaped stepped portion 26a, and the tip of the upper surface portion 21 is located on the second panel side (inward) than the connecting portion 26. In response to this, the tip of the upper surface portion 11 of the first panel protrudes further outward (towards the second panel) than the connecting portion 26. Therefore, the tip of this upper surface portion 11 is extended downward to form the first locking portion 11a, and the base of the first protrusion 24 of the second panel is pulled upward to form the first locked portion 24a. In another example, a second locking portion 12a is provided on the tip side of the lower surface portion 12 of the first panel, and a second locking portion 25a is provided on the tip side of the second protrusion 25 of the second panel so as to be able to lock onto the second locking portion. However, the positions of the locking portion and the locking portion can be selected as appropriate. Preferably, the pair of recesses and protrusions are fitted together with a gap of a predetermined clearance, and the provided locking portion and the locked portion lock together when a load is applied. In this way, for example, when the upper surfaces 11 and 21 of each panel are approximately horizontal, the recesses and protrusions (locking parts and locked parts) do not interfere with each other, allowing for smooth panel connection work. The locking portion and the locked portion may each be claw-shaped, and the claws may interlock when the panel is slightly tilted. By providing a locking portion and a locked portion in this manner, as shown in Figures 3 and 4, even if a load is applied upward from the lower side of either adjacent panel, the first locking portion 11a and the first locked portion 24a, and / or the second locking portion 12a and the second locked portion 25a will lock together, resulting in high strength at the connecting portion. [Explanation of symbols]

[0016] 1 Under member 2 Cases 3 Battery pack 10. Panel 1 11a 1st locking part 12a Second locking part 17. First recess 18. Second recess 20 Panel 2 24 First protrusion 24a 1st locked part 25 Second protrusion 25a Second locked part

Claims

1. A protective structure for a battery pack mounted under the floor of a vehicle, It comprises a case body housing a battery pack and an under member disposed below the case body, The aforementioned under member consists of multiple panels, One of the multiple panels, adjacent to the other, has an upper surface portion, a lower surface portion, and a first rib connecting the upper surface portion and the lower surface portion, and the upper surface portion has a first locking portion that protrudes substantially horizontally from the first rib, The lower portion has a second locking portion that protrudes substantially horizontally from the first rib, The first rib has an intermediate portion that protrudes between the first locking portion and the second locking portion, and the first locking portion and the intermediate portion form a first recess. A second recess is formed between the second locking portion and the intermediate portion. The other panel has an upper portion, a lower portion, and a connecting portion connecting the ends of the upper portion and the lower portion, and the connecting portion has a first fitting piece consisting of a first protrusion that fits and locks into the first recess and a second fitting piece consisting of a second protrusion that fits and locks into the second recess, characterized in that it is a protective structure for a battery pack.

2. The battery pack protection structure according to Claim 1, characterized in that the first recess and the second recess have different recess depths in their recess shape.

3. The battery pack protection structure according to claim 1 or 2, characterized in that the first recess and the first fitting piece and the second recess and the second fitting piece lock together when a load is applied from below to above the under member.

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