Battery Pack Protection Device

Abstract

While ensuring space inside the vehicle, it also reduces damage to the battery pack caused by objects falling on the road while driving. [Solution] The vehicle comprises a first protective body 2 having a base 4 attached to the lower part of the front cross member 21 and a crushable portion 5 fixed to the underside of the base 4, and a second protective body 3 having a base 6 attached to the lower part of the rear cross member 24 and a crushable portion 7 fixed to the underside of the base 6, wherein the first protective body 2 is provided between the front pair of tires 23 and is positioned within a range that does not extend beyond the circumference of the front pair of tires 23 when viewed from the side, and the second protective body 3 is provided between the rear pair of tires 26 and is positioned within a range that does not extend beyond the circumference of the rear pair of tires 26 when viewed from the side, and the first protective body 2 and the second protective body 3 are offset toward the battery pack 27 in the fore-and-aft direction of the vehicle.

Description

[Technical Field]

[0001] The present invention relates to a battery pack protection device that protects a battery pack that supplies power to a traction motor of an electric vehicle. [Background technology]

[0002] Conventionally, some electric vehicles have a battery pack that supplies power to a driving motor and is located below the floor panel. The battery pack located below the floor panel may be damaged by collisions with stones, foreign objects, or other falling objects on the road while the vehicle is traveling. To prevent damage to the battery pack, for example, Patent Document 1 discloses a battery pack in which a protective plate is located below the bottom surface of a battery case that houses multiple battery stacks.

[0003] The battery pack described in Patent Document 1 includes a cooler arranged on the bottom surface of a battery case and a cushioning member. In the cooler, a cooling module is arranged for each of a plurality of battery stacks, and a connection part is provided to connect adjacent cooling modules. A cushioning member is arranged between the protective plate and the connection part, and a weakened part is formed in the part of the connection part where the cushioning member is arranged.

[0004] In the battery pack described in Patent Document 1, when a foreign object on the road collides with the protective plate while the vehicle is traveling, the protective plate bulges upward, causing the buffer material to shrink and deform, while pressing the connection part upward. At this time, the buffer material bends starting from the weak part of the connection part, thereby absorbing the impact of the collision.

[0005] Furthermore, in order to prevent damage to the battery pack, for example, Patent Document 2 discloses a battery pack in which a plurality of first skeletal members and a plurality of second skeletal members are provided on the bottom of the battery pack case (battery case). In the battery pack described in Patent Document 2, the plurality of first skeletal members extend in the vehicle width direction and are arranged at intervals from each other in the vehicle front-rear direction. The plurality of second skeletal members extend in the vehicle front-rear direction and are arranged at intervals from each other in the vehicle width direction.

[0006] In the battery pack described in Patent Document 2, the plurality of first skeletal members and the plurality of second skeletal members can prevent the bottom of the battery case from being hit by falling objects on the road surface when the vehicle is traveling. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2023-046518 [Patent Document 2] Japanese Patent Publication No. 2020-114701 Summary of the Invention [Problem to be solved by the invention]

[0008] The battery pack described in Patent Document 1 has a space between the bottom of the battery case and the protective plate. This space needs to be large enough in the vertical direction so that when an object that has fallen on the road surface hits the protective plate while the vehicle is in motion, the protective plate does not bulge upward and hit the bottom of the battery case. This space can be secured by raising the position of the battery case. However, raising the position of the battery case also raises the position of the floor panel, which can reduce the space inside the vehicle.

[0009] The battery pack described in Patent Document 2 requires space below the battery case to accommodate multiple first skeletal members and multiple second skeletal members. This space can be secured by raising the position of the battery case. However, raising the position of the battery case also raises the position of the floor panel, which can reduce the vehicle interior space.

[0010] Therefore, an object of the present invention is to prevent damage to the battery pack caused by objects falling on the road surface while driving, while ensuring sufficient space in the vehicle interior. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention can employ the following configurations 1 to 5. [Configuration 1] A battery pack protection device for protecting a battery pack mounted in a vehicle, A battery pack protection device having a protector provided in front of the battery pack and between a pair of front tires of the vehicle, the bottom surface of the protector being positioned lower than the bottom surface of the battery pack.

[0012] [Configuration 2] The battery pack protection device according to configuration 1, wherein the protector is further provided behind the battery pack and between a pair of rear tires of the vehicle.

[0013] [Configuration 3] The battery pack protection device according to configuration 1 or 2, wherein the protector has a tapered portion that extends downward on the outer side in the vehicle longitudinal direction and slopes inward in the vehicle longitudinal direction.

[0014] [Configuration 4] The protection body is offset toward the battery pack in the vehicle front-rear direction, The battery pack protection device according to configuration 1 or 2, wherein the protection body is positioned within a range that does not extend beyond the circumference of the pair of tires between which the protection body is provided when viewed from the side.

[0015] [Configuration 5] a protector provided behind the battery pack and between a pair of rear tires of the vehicle has a variable mechanism for changing the vertical position of a bottom portion of the protector; The battery pack protection device according to configuration 2, wherein the variable mechanism is inactive when a parking structure is detected, and is activated to lower the position of the bottom when an object falling on the road surface is detected. [Effects of the Invention]

[0016] According to this invention, when the vehicle is traveling, the protective body provided in front of the battery pack crushes or bounces off objects that fall on the road surface, thereby preventing objects from colliding with the bottom of the battery pack, eliminating the need to raise the position of the battery pack relative to the road surface and ensuring space in the vehicle interior. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a side view showing a vehicle to which a battery pack protection device according to a first embodiment of the present invention is applied; [Figure 2] FIG. 1 is a bottom view showing a vehicle to which the battery pack protection device of the same is applied; [Figure 3] Cross section along line AA in Figure 2 [Figure 4] Cross-sectional view taken along line BB in Figure 2 [Figure 5] FIG. 10 is a side view showing a vehicle to which a battery pack protection device according to a second embodiment of the present invention is applied. [Figure 6] FIG. 1 is an enlarged side view showing a main part of a vehicle to which the battery pack protection device of the present invention is applied. DETAILED DESCRIPTION OF THE INVENTION

[0018] A battery pack protection device 1 according to a first embodiment of the present invention will be described with reference to the drawings. As shown in Figures 1 to 3, the battery pack protection device 1 is applied to an electrically powered vehicle 20, such as an electric vehicle or a hybrid vehicle, equipped with a battery pack 27 that supplies power to a traction motor.

[0019] The electric vehicle 20 includes a front motor 22 and a pair of front tires 23 attached to a front cross member 21, a rear motor 25 and a pair of rear tires 26 attached to a rear cross member 24, a battery pack 27 disposed below a floor panel 30, and a battery pack protection device 1. In the following description, the up-down direction, the front-rear direction, and the vehicle width direction are based on the vehicle parked on level ground.

[0020] The front cross member 21 is attached to the front lower surfaces of a pair of front side members 28. The front cross member 21 is a frame-shaped member in a plan view. As shown in Fig. 2, the front cross member 21 has a pair of side members 21a extending in the vehicle width direction and a pair of cross members 21b extending in the front-rear direction that spans between the pair of side members 21a.

[0021] A front motor 22 is disposed between the pair of side members 21a in the vehicle width direction and between the pair of cross members 21b in the front-rear direction. Lower arms 21c are attached to both sides of the pair of side members 21a in the vehicle width direction. A pair of front tires 23 are rotatably attached to the pair of side members 21a via the lower arms 21c.

[0022] The rear cross member 24 is attached to the lower part of a pair of rear side members 29. The rear cross member 24 is a frame-shaped member in a plan view. As shown in Fig. 2, the rear cross member 24 has a pair of side members 24a extending in the vehicle width direction and a pair of cross members 24b extending in the front-rear direction that spans between the pair of side members 24a.

[0023] A rear motor 25 is disposed between the pair of side members 24a in the vehicle width direction and between the pair of cross members 24b in the front-rear direction. A pair of rear tires 26 are rotatably attached to the pair of side members 24a via lower arms 24c.

[0024] The battery pack 27 has a plurality of battery cells (not shown) that supply power to the front motor 22 and the rear motor 25, and a flat, box-shaped case 27a that houses the plurality of battery cells. Fixing pieces 27b are provided at multiple locations in the front-to-rear direction of the vehicle on both sides of the case 27a in the vehicle width direction. Each fixing piece 27b is fixed to the lower surface of a pair of front side members 28. A floor panel 30 is attached to the upper part of the battery pack 27.

[0025] The battery pack protection device 1 is composed of a first protection body 2 attached to the lower part of the front cross member 21 and a second protection body 3 attached to the lower part of the rear cross member 24. As shown in FIG. 2 , the first protection body 2 is fixed to a pair of side members 21a of the front cross member 21. The first protection body 2 has a base 4 and a crushable part 5 fixed to the lower surface of the base 4.

[0026] The base 4 is formed from a metal plate that is rectangular in plan view. The base 4 is fixed to the front cross member 21 with its length aligned with the vehicle width direction. The base 4 has a width dimension in the vehicle width direction that is slightly smaller than that of the battery pack 27. Two fasteners 4a are integrally provided on each of the front and rear end faces of the base 4. The two front fasteners 4a protrude forward from the front end face of the base 4. The two rear fasteners 4a protrude rearward from the rear end face of the base 4.

[0027] The fixing device 4a has an upper surface portion 4b located at the upper end side and a pair of side surfaces 4c integrally formed on both sides of the upper surface portion 4b in the vehicle width direction. The upper surface of the upper surface portion 4b is located on the same plane as the upper surface of the base portion 4. The pair of side surfaces 4c are inclined downward from both ends of the upper surface portion 4b in the vehicle width direction toward the outside in the vehicle width direction and extend outward in the vehicle width direction from their lower ends. The lower surfaces of the extending portions of the pair of side surfaces 4c are located on the same plane as the lower surface of the base portion 4.

[0028] Of the two fixing devices 4a located on the front and rear sides of the base 4, the upper surface 4b of the fixing device 4a located on one side in the vehicle width direction is fastened to the cross member 21b located on one side in the vehicle width direction by fasteners 31 consisting of bolts and nuts. Of the two fixing devices 4a located on the front and rear sides of the base 4, the upper surface 4b of the fixing device 4a located on the other side in the vehicle width direction is fastened to the cross member 21b located on the other side in the vehicle width direction by fasteners 31 consisting of bolts and nuts. As a result of this fastening, the base 4 is offset toward the battery pack 27 in the front-rear direction (rear side in the front-rear direction of the vehicle). As shown in FIG. 1, the base 4 is positioned within a range that does not extend beyond the circumference of the pair of front tires 23 when viewed from the side.

[0029] The crushing unit 5 is a rectangular metal plate-like member. The crushing unit 5 is fixed to the underside of the base 4 with the length direction of the crushing unit 5 aligned with the vehicle width direction. The crushing unit 5 has a width dimension in the vehicle width direction that is slightly smaller than that of the base 4. As shown in FIG. 2, the crushing unit 5 has tapered portions 5a on the front and rear sides, which are on the outer sides in the vehicle longitudinal direction, that slope downward and inward in the vehicle longitudinal direction. The crushing unit 5 has tapered portions 5b on both sides in the vehicle width direction that slope downward and inward in the vehicle width direction.

[0030] As shown in FIG. 1, the crushing unit 5 is fixed in a state where it is offset toward the battery pack 27 in the vehicle's longitudinal direction (rearward in the vehicle's longitudinal direction) when viewed from the side. When viewed from the side, the crushing unit 5 is arranged within a range that does not extend beyond the circumference of the front pair of tires 23. The bottom surface of the crushing unit 5 is located lower than the bottom surface of the battery pack 27. Therefore, as shown in FIG. 3, the height h1 from the road surface G to the bottom surface of the crushing unit 5 is smaller than the height h0 from the road surface G to the bottom surface of the battery pack 27.

[0031] The second protection body 3 has a base 6 and a crushable portion 7 fixed to the underside of the base 6. The base 6 has the same structure as the base 4 of the first protection body 2, the only difference being that the object to which it is fixed is the rear cross member 24. For this reason, the base 6 is given the same reference numerals as the respective parts of the base 4, and a description of its structure will be omitted.

[0032] As shown in FIG. 2, the base 6 is fixed to the rear cross member 24 with its length aligned with the vehicle width direction. The base 6 has a width dimension in the vehicle width direction that is slightly smaller than that of the battery pack 27. Of the two fixing devices 4a located on the front and rear sides of the base 6, the upper surface 4b of the fixing device 4a located on one side in the vehicle width direction is fastened to the cross member 24b located on one side in the vehicle width direction with fasteners 31 consisting of bolts and nuts. Of the two fixing devices 4a located on the front and rear sides of the base 6, the upper surface 4b of the fixing device 4a located on the other side in the vehicle width direction is fastened to the cross member 24b located on the other side in the vehicle width direction with fasteners 31 consisting of bolts and nuts. As a result of this fastening, the base 6 is offset toward the battery pack 27 in the fore-and-aft direction (front side in the vehicle fore-and-aft direction). As shown in FIG. 1, the base 6 is positioned within a range that does not extend beyond the circumference of the pair of rear tires 26 when viewed from the side.

[0033] The crushing portion 7 is a rectangular metal plate-like member having the same shape as the crushing portion 5 of the first protector 2. The crushing portion 7 is fixed to the underside of the base 6 with the length of the crushing portion 7 aligned with the vehicle width direction. As shown in FIG. 4, the crushing portion 7 has a width dimension in the vehicle width direction that is slightly smaller than that of the base 6. The crushing portion 7 has tapered portions 7a on the front and rear sides, which are on the outer sides in the vehicle longitudinal direction, that slope downward and inward in the vehicle longitudinal direction. The crushing portion 7 also has tapered portions 7b on both sides in the vehicle width direction that slope downward and inward in the vehicle width direction.

[0034] As shown in FIG. 1, the crushing unit 7 is fixed in a state offset toward the battery pack 27 in the front-to-rear direction (front side in the front-to-rear direction of the vehicle) when viewed from the side. When viewed from the side, the crushing unit 7 is arranged within a range that does not extend beyond the circumference of the pair of rear tires 26. The bottom surface of the crushing unit 7 is located lower than the bottom surface of the battery pack 27. Therefore, as shown in FIG. 4, the height h2 from the road surface G to the bottom surface of the crushing unit 7 is smaller than the height h0 from the road surface G to the bottom surface of the battery pack 27.

[0035] The battery pack protection device 1 according to the first embodiment of the present invention is configured as described above. The battery pack protection device 1 of this embodiment comprises a first protection body 2 attached to the lower part of the front cross member 21 and a second protection body 3 attached to the lower part of the rear cross member 24. The first protection body 2 is provided between the front pair of tires 23. The bottom surface of the crushing portion 5 of the first protection body 2 is located lower than the bottom surface of the battery pack 27. Therefore, when the electric vehicle is traveling, falling objects R such as stones or foreign objects on the road surface G are bounced off or crushed by the base 4 and crushing portion 5 of the first protection body 2.

[0036] The size of the broken falling objects R is reduced, and the chances of them colliding with the bottom surface of the battery pack 27 are reduced, thereby suppressing damage to the battery pack 27. As a result, it is no longer necessary to raise the position of the battery pack 27 to suppress damage to the battery pack 27, as was conventional, and space in the vehicle interior can be secured. Furthermore, since it is not necessary to raise the position of the battery pack 27, the height from the road surface G to the bottom surface of the battery pack 27 (height above ground) can be secured, and the center of gravity of the battery pack 27 can be lowered. Furthermore, since it is no longer necessary to provide a protective plate or the like on the bottom of the battery pack, as was conventional, it is possible to reduce the weight and cost of the battery pack 27.

[0037] In the battery pack protection device 1 of this embodiment, the second protector 3 is attached to the lower part of the rear cross member 24. The second protector 3 is provided between the pair of rear tires 26, and the bottom surface of the crushing portion 7 of the second protector 3 is positioned lower than the bottom surface of the battery pack 27. When the electric vehicle 20 is backing up, a falling object R that has a large road surface G can be received by the base portion 6 and crushing portion 7 of the second protector 3. This prevents the falling object R from getting caught below the battery pack 27 and damaging the battery pack 27.

[0038] 1, in the battery pack protection device 1 of this embodiment, the crushing portion 5 of the first protector 2 has tapered portions 5a that slope downward and inward in the vehicle longitudinal direction on the front and rear sides that are outward in the vehicle longitudinal direction. When the electric vehicle 20 is traveling, an object R that has fallen on the road surface G hits the front tapered portion 5a of the crushing portion 5 and is caught between the crushing portion 5 and the road surface G, making it easier to crush the object R that has fallen on the road surface G.

[0039] The crushing portion 7 of the second protective body 3 has tapered portions 7a that slope downward and inward in the vehicle longitudinal direction on the front and rear sides that are on the outer sides in the vehicle longitudinal direction. When the electric vehicle 20 is moving backward, fallen object R on the road surface G hits the tapered portion 7a on the rear side of the crushing portion 7 and gets caught between the crushing portion 7 and the road surface G, making it easier to crush the fallen object R on the road surface G.

[0040] In the battery pack protection device 1 of this embodiment, the base 4 and crushing unit 5 of the first protector 2 are offset toward the battery pack 27 in the front-rear direction. When viewed from the side, the base 4 and crushing unit 5 are arranged within a range that does not extend beyond the circumference of the front pair of tires 23. As a result, when the electric vehicle 20 is traveling, if a fallen object R on the road surface G is bounced outward in the vehicle width direction by the base 4 or the crushing unit 5, the bounced fallen object R will hit the front pair of tires 23. This makes it possible to prevent the fallen object R from being bounced onto a sidewalk or the like that is located around the electric vehicle 20 and outward in the vehicle width direction.

[0041] As shown in FIG. 1 , the base 4 and the crushable portion 5 of the first protector 2 are disposed within a range that does not extend beyond the circumference of the front pair of tires 23 in a side view. Therefore, the base 4 and the crushable portion 5 of the first protector 2 do not protrude downward from a front virtual line X that forms an approach angle with the road surface G in a side view. Similarly, the base 6 and the crushable portion 7 of the second protector 3 are disposed within a range that does not extend beyond the circumference of the rear pair of tires 26 in a side view. Therefore, the base 6 and the crushable portion 7 of the second protector 3 do not protrude downward from a rear virtual line Y that forms a departure angle with the road surface G in a side view. Therefore, when the electric vehicle 20 is traveling on a slope or an uneven road surface, the first protector 2 and the second protector 3 can be prevented from interfering with the slope or the road surface.

[0042] Next, a battery pack protection device 11 according to a second embodiment of the present invention will be described with reference to Figures 5 and 6. This battery pack protection device 11 differs from the battery pack protection device 1 according to the first embodiment described above in that the crushable portion 7 of the second protector 3 is capable of swinging up and down relative to the base 6 via a link mechanism 12 as a variable mechanism, and in that it has an operating means for operating the link mechanism 12. The other components are the same as those in the first embodiment, so the same reference numerals as in the first embodiment are used and their explanations will be omitted.

[0043] In addition, the electric vehicle 20 equipped with the battery pack protection device 11 has a detection means for detecting the condition of the road surface G behind the electric vehicle 20, and a control unit for controlling the operation of the link mechanism 12 based on the condition of the road surface G detected by the detection means.

[0044] In this embodiment, the base 6 and the crushing unit 7 have the same width dimension in the vehicle width direction, and have a width dimension in the vehicle width direction that is slightly smaller than that of the battery pack 27. The link mechanism 12 is a parallel link mechanism having a pair of link members 12a. The link mechanism 12 is arranged on both sides of the base 6 and the crushing unit 7 in the vehicle width direction. One end of the pair of link members 12a in the length direction is rotatably attached to the outer end surface of the base 6 in the vehicle width direction. The other end of the pair of link members 12a in the length direction is rotatably attached to the outer end surface of the crushing unit 7 in the vehicle width direction. The pair of link members 12a are inclined so as to face downward toward the rear in the vehicle fore-and-aft direction.

[0045] 5, the crushing unit 7 is configured to swing downward toward the front in the vehicle longitudinal direction relative to the base 6 by the link mechanism 12, thereby changing the vertical position of its bottom. The second protector 3 is provided with an operating means (not shown) that operates the link mechanism 12. For example, a motor or an actuator can be used as the operating means.

[0046] The control unit that controls the operation of the link mechanism 12 may be, for example, a control unit (not shown) that controls the operation of various electrical devices provided in the electric vehicle 20. The detection means that detects the state of the road surface G behind the electric vehicle 20 may be, for example, a sensor camera (not shown) that captures image information of the surroundings of the electric vehicle 20.

[0047] The control unit that controls the operation of the link mechanism 12 controls the link mechanism 12 not to operate (not to operate) using the operating means when the electric vehicle 20 is traveling forward and when the electric vehicle 20 is stopped, and places the crushing section 7 in a state of contact with the base 6.

[0048] 5, when the control unit detects a fallen object R on the road surface G based on image information from the detection unit while the electric vehicle 20 is moving backward, the control unit controls the actuation unit to operate the link mechanism 12. This control causes the crushing unit 7 to swing downward toward the front in the vehicle longitudinal direction relative to the base 6, lowering the position of the bottom of the crushing unit 7. This allows the crushing unit 7 to receive the fallen object R on the road surface G, preventing damage to the battery pack 27 caused by the fallen object R from the road surface G getting caught below the battery pack 27.

[0049] On the other hand, as shown in Fig. 6, when the control unit detects parking structures such as a lock plate drive unit 32 and a lock plate 33 installed in a coin parking lot, or tire stops in the parking lot (not shown) based on image information from the detection means when the electric vehicle 20 is backing up, the control unit controls the actuation means not to actuate (deactivate) the link mechanism 12. This control brings the crushing unit 7 into contact with the base 6, preventing the crushing unit 7 from colliding with the parking structure.

[0050] In this embodiment, the configuration of the present invention has been explained assuming an electric vehicle (electric vehicle (EV)) that has only a front motor 22 and a rear motor 25 as a driving source for driving, but the present invention can also be applied to hybrid vehicles (HVs) that have a motor and an engine as a driving source for driving, in particular plug-in hybrid vehicles (PHEVs) that can externally charge the onboard secondary battery from an external charging facility and can also externally supply power from the secondary battery to external devices, and fuel cell vehicles (FCEVs) that have a hydrogen tank or the like for storing hydrogen as fuel and a fuel cell below the floor panel. [Explanation of symbols]

[0051] 1, 11 Battery pack protection device 2 Primary protector 3 Second protector 4, 6 base 4a Fixture 5, 7 Crushing section 5a, 5b, 7a, 7b Taper part 12 Link mechanism 12a Link member 20 Electric Vehicles 21 Front cross member 21a, 24a Side members 21b, 24b cross members 21c, 24c lower arm 22 Front motor 23, 26 tires 24 Rear cross member 25 rear motor 27 Battery Pack 27a Case 27b Fixed piece 28 Front side member 29 Rear side member 30 Floor Panel 31 Fasteners 32 Lock plate drive unit 33 Locking Plate G road surface R Falling Objects

Claims

1. A battery pack protection device for protecting a battery pack mounted in a vehicle, A battery pack protection device having a protector provided in front of the battery pack and between a pair of front tires of the vehicle, the bottom surface of the protector being positioned lower than the bottom surface of the battery pack.

2. 2. The battery pack protection device according to claim 1, wherein the protection body is further provided behind the battery pack and between a pair of rear tires of the vehicle.

3. 3. The battery pack protection device according to claim 1, wherein the protector has a tapered portion that extends downward on an outer side in the vehicle longitudinal direction and then slopes inward in the vehicle longitudinal direction.

4. The protection body is offset toward the battery pack in the vehicle front-rear direction, 3. The battery pack protection device according to claim 1, wherein the protection body is disposed within a range that does not extend beyond the circumference of the pair of tires between which the protection body is disposed when viewed from the side.

5. a protector provided behind the battery pack and between a pair of rear tires of the vehicle has a variable mechanism for changing the vertical position of a bottom portion of the protector; 3. The battery pack protection device according to claim 2, wherein the variable mechanism is deactivated when a parking structure is detected, and is activated to lower the position of the bottom portion when an object falling on the road surface is detected.

Images