Vehicle battery case

Abstract

To provide a vehicle battery case that can suppress water adhesion to battery cells and other components. [Solution] A battery case 12 for a battery includes a lower case 22. A recess 40 is formed in a bottom plate 24 of the lower case 22 near a corner 44RF on the vehicle rear side, and water can be stored in the recess 40 in the lower case 22. This allows the battery case 12 to increase the amount of water that can immerse the battery modules, and the battery case 12 can prevent the battery modules from becoming immersed in water compared to when the bottom plate 24 does not have the recess 40.

Description

[Technical Field]

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

[0002] Patent Document 1 describes a battery pack installed on the floor of a vehicle. The battery pack has multiple battery cells arranged in a battery pack case, and the battery pack case has a lower case in which the multiple battery cells are arranged in a row, and an upper case which isolates the space in the lower case in which the battery cells are arranged from the surroundings. The lower case of the battery pack case is fixed to the floor of the vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-123227 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in vehicles, the underside of the vehicle body where the battery case is attached can be splashed with or submerged in rainwater that has accumulated on the road surface. As a result, rainwater easily adheres to the battery case, and this water can seep inside. In the battery case, there is a concern that the water that seeps inside may accumulate and adhere to the battery pack inside the battery case, or to the battery cells inside the battery pack.

[0005] If a battery pack or the battery cells inside the battery pack become submerged in water, the battery performance will be reduced. Therefore, there is room for improvement in terms of preventing water from adhering to or submerging the battery cells in the battery case.

[0006] This invention was made in view of the above facts, and aims to provide a vehicle battery case that can prevent water that has entered the interior from adhering to battery cells and the like. [Means for solving the problem]

[0007] In order to achieve the above object, the vehicle battery case of the first aspect includes a case body having a rectangular parallelepiped outer shape in which a battery module having a plurality of stacked battery cells in an internal space is placed on the inner surface of a bottom plate and housed therein, and the case body has a recess that opens upward at a corner on the inner surface of the bottom plate.

[0008] In the vehicle battery case according to the first embodiment, a battery module is housed in the internal space of the case body, which has an external rectangular parallelepiped shape. This battery module consists of multiple battery cells stacked and placed on the inner surface of the bottom plate of the case body.

[0009] In this case body, a recess that opens upward is formed in a corner on the inside surface of the bottom plate. As a result, when water seeps into the inside of the case body and accumulates on the bottom plate, some of the water can be stored in the recess formed in the bottom plate, and when water does seep into the inside of the case body, the battery modules and battery cells can be prevented from being submerged in the water compared to when a recess is not formed.

[0010] A vehicle battery case according to a second aspect includes the first aspect, wherein the recess is formed in a vehicle rear side portion of the bottom plate.

[0011] In the vehicle battery case according to the second embodiment, a recess is formed in the rear portion of the bottom plate. Therefore, in the case body, if water accumulates on the bottom plate, it can be allowed to enter the recess on the rear portion of the bottom plate, effectively preventing the battery module or battery cells from being submerged in the infiltrated water.

[0012] A vehicle battery case according to a third embodiment includes, in the first or second embodiment, a water level detection unit for detecting the amount of water accumulated on the bottom plate at the front of the vehicle in the case body.

[0013] In the third embodiment of the vehicle battery case, a water level detection unit is provided at the front of the vehicle to detect the amount of water accumulated on the bottom plate. This makes it possible to detect when water has entered the case body and to prevent the battery module or battery cells from being submerged in the water. [Effects of the Invention]

[0014] According to the present invention, by providing a recess in the rear portion of the bottom plate, some of the water that has entered can be contained within the recess. This has the effect of suppressing the water from adhering to or soaking the battery module or battery cells compared to the case where no recess is provided. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a schematic diagram showing the configuration of a battery according to an embodiment of the present invention; [Figure 2] FIG. 2 is a plan view showing a main portion of the lower case on the vehicle rear side. [Figure 3] FIG. 2 is a perspective view showing a main part of the lower case on the vehicle rear side. [Figure 4] FIG. 2 is a perspective view showing a main part of the lower case on the vehicle front side. [Figure 5] FIG. 5 is a perspective view showing a main part of the vehicle front side of the lower case, seen from a direction different from that of FIG. 4. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the vehicle battery case of the present invention will be described in detail with reference to the drawings. The vehicle battery case is used when mounted in a vehicle. 1 is a perspective view showing the schematic configuration of a battery (battery pack) 10 according to this embodiment. In the drawing, the front side of the vehicle is indicated by an arrow FR, the right side in the vehicle width direction is indicated by an arrow HR, and the upward direction is indicated by an arrow UP.

[0017] The battery 10 is installed in a vehicle (not shown) equipped with an electric motor as a drive source for driving, for example, and outputs DC power that can be applied to drive the electric motor. Vehicles in which the battery 10 is installed include hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs).

[0018] As shown in Figure 1, the battery 10 comprises a vehicle battery case and a battery case body 12 according to this embodiment, and a battery pack 14 housed inside the battery case 12. The battery case 12 is roughly rectangular in shape and is positioned below the floor panel, which serves as the floor of the vehicle, and above the under cover, and is attached to the vehicle body (neither of which are shown in the illustration).

[0019] The battery case 12 includes an upper case 20 and a lower case 22, and the upper case 20 and the lower case 22 are opposed to each other with the upper case 20 on the upper side and the lower case 22 on the lower side.

[0020] The lower case 22 is equipped with a bottom plate 24 that is roughly rectangular in plan view. The lower case 22 also has a peripheral wall 26 erected around the bottom plate 24, and a flange portion 28 is formed on the peripheral wall 26 with its upper part bent outward from the lower case 22, extending almost all the way around. The bottom plate 24, peripheral wall 26 and flange portion 28 of the lower case 22 are integrally formed, and the lower case 22 is roughly rectangular in shape, like a tray (or tub).

[0021] The upper case 20 also has a top plate 30 that is roughly rectangular in plan view. The upper case 20 also has a peripheral wall 32 projecting downwards around the top plate 30, and the tip (lower end) of the peripheral wall 32 is folded outwards along almost the entire circumference of the upper case 20 to form a flange portion 34. The upper case 20 is integrally formed with the top plate 30, peripheral wall 32 and flange portion 34.

[0022] The battery case 12 is assembled by stacking the flange portion 34 of the upper case 20 and the flange portion 28 of the lower case 22 facing each other. In the battery case 12, the flange portion 34 of the upper case 20 and the flange portion 28 of the lower case 22 are fastened together using fastening means such as bolts and nuts, and the internal space is sealed from the outside (not shown).

[0023] In the battery case 12, the boundary between the top plate 30 and the peripheral wall 32 in the upper case 20, and the boundary between the bottom plate 24 and the peripheral wall 26 in the lower case 22, etc. are chamfered to curve the outer surfaces.

[0024] In the battery 10, a battery pack 14 is housed in the internal space of a battery case 12. In this case, the battery pack 14 is covered from the top and bottom by a bottom plate 24 and a top plate 30, and is surrounded by a peripheral wall 26 and a peripheral wall 32. The battery case 12 functions as a battery pack case in which the battery pack 14 is housed.

[0025] The battery pack 14 is composed of one or more battery modules 16, and each battery module 16 has multiple battery cells (not shown) stacked on top of each other. The battery case 12 houses multiple battery modules 16. Note that the battery case 12 may house only one battery module 16, not just multiple modules.

[0026] In the battery 10 (battery pack 14), for example, a plurality of battery modules 16 are connected in parallel or in series. In addition, in the battery pack 14, auxiliary equipment 36 is arranged together with the plurality of battery modules 16. The auxiliary equipment 36 includes a controller (not shown) that controls the operation of the battery modules 16 and the battery cells included in the battery modules 16 based on various sensors and the information detected by the sensors. As a result, the battery 10 (battery pack 14) outputs DC power of a required voltage during discharge, and charges each of the plurality of battery cells of the battery module 16 by inputting DC power of the required voltage.

[0027] In the battery case 12, a plurality of mount portions 18 are formed on the bottom plate 24 of the lower case 22. The mount portions 18 are, for example, rectangular block-shaped (or plate-shaped), each with its longitudinal direction aligned with the vehicle width direction, and are arranged at predetermined intervals in the fore-and-aft direction of the vehicle.

[0028] In the lower case 22, an upper surface 24A of the bottom plate 24 (peripheral edge of the bottom plate 24) between the mount portion 18 and the peripheral wall 26 is formed as a lower portion (deep bottom portion) 24B that is lower than the central portion. The battery modules 16 are placed on the mount portion 18 and arranged on the bottom plate 24 of the lower case 22, and are disposed inside the battery case 12.

[0029] As a result, the battery module 16 is arranged in the battery case 12, floating by the height of the stand portion 18 relative to the upper surface 24A of the bottom plate 24. Furthermore, the peripheral edge of the bottom plate 24 of the battery case 12 is formed as a lower portion 24B relative to the upper surface 24A on which the battery pack 14 is arranged, so that the peripheral edge is even lower relative to the lower surface of the battery pack 14.

[0030] On the other hand, the battery case 12 has a substantially rectangular box shape, and therefore has corners 44 at its four corners. The four corners 44 are corner 44RF on the front side of the vehicle and on the right side in the vehicle width direction, corner 44LF on the front side of the vehicle and on the left side in the vehicle width direction, corner 44RB on the rear side of the vehicle and on the right side in the vehicle width direction, and corner 44LB on the rear side of the vehicle and on the left side in the vehicle width direction.

[0031] The lower case 22 of the battery case 12 has recesses 40 as volume-increasing portions at corners 44 of the bottom plate 24. In addition, the lower case 22 has protrusions and bead portions as protruding portions at corners 44 of the bottom plate 24 that do not have recesses 40.

[0032] Figure 2 shows the main rear portion of the lower case 22 in a plan view, and Figure 3 shows the main rear portion of the lower case 22 in a perspective view. Figure 4 shows the main front portion of the lower case 22 in a perspective view, and Figure 5 shows the main front portion of the lower case 22 in a perspective view from a different direction than in Figure 4. In Figure 3, corner 44RB is shown in an oblique upward view from the front right, in Figure 4, corner 44RF is shown in an oblique upward view from the rear left, and in Figure 5, the vicinity of corner 44RF is shown in an oblique upward view from the front right.

[0033] As shown in Figures 2 and 3, a recess 40 is formed in the lower plate 24 of the lower case 22 at the lower rear portion 24B of the vehicle. In the lower case 22, the recess 40 is formed near the corner 44RB and near the corner 44LB. The recess 40 near the corner 44RB and the recess 40 near the corner 44LB have similar configurations, and in the following, the recess 40 near the corner 44RB will be mainly described, and the description of the recess 40 near the corner 44LB will be omitted.

[0034] The recess 40 is formed in the lower part 24B of the bottom plate 24 as a groove (with a bottom) that opens upward. The recess 40 extends from the corner 44RB side toward the front of the vehicle and also extends from the corner 44RB side toward the left side in the vehicle width direction. As a result, the recess 40 has a roughly L-shape when viewed from above. In the lower case 22, the volume is increased by the volume of the recess 40 due to the formation of the recess 40 in the bottom plate 24.

[0035] In addition, by forming a recess in the lower case 22, a bead portion (not shown) is formed on the lower surface of the bottom plate 24, and the bead portion corresponding to the recess 40 is formed in a generally L-shape and protrudes from the lower surface. Therefore, the bead portion corresponding to the recess 40 has a portion extending in the vehicle width direction and a portion extending in the vehicle front-rear direction, which are integrated. This prevents the lower case 22 from being thin in the recess 40 area, even though the recess 40 is formed, and thus prevents a decrease in strength.

[0036] 4 and 5, the bottom plate 24 of the lower case 22 has bead portions 60 formed as convex portions and convex-shaped portions in the low portion 24B on the vehicle front side. In the lower case 22, the bead portions 60 are formed near the corners 44RF and 44LF. Note that the bead portions 60 near the corners 44RF and 44LF have the same basic configuration, and therefore, the following description will mainly focus on the bead portions 60 near the corners 44RF, and will omit a description of the bead portions 60 near the corners 44LF.

[0037] The bead portion 60 is formed to protrude upward from the low portion 24B of the bottom plate 24. The bead portion 60 is formed so as to be inward in the vehicle width direction (toward the left in the vehicle width direction) from the corner portion 44RF side toward the rear of the vehicle, and the bead portion 60 is inclined with respect to both the front-rear direction of the vehicle and the vehicle width direction. As a result, the volume of the lower case 22 is increased by the volume of the bead portion 60 near the low portion 24B of the bottom plate 24 on the vehicle front side.

[0038] Meanwhile, in the battery case 12, a water detection sensor (water level detection sensor) 50 serving as a water amount detection unit and a water detection unit is disposed in the lower case 22. As shown in Fig. 5, the water detection sensor 50 is disposed on the front side of the vehicle in the lower case 22, and the water detection sensor 50 is disposed near a bead portion 60, which is, for example, near the corner 44RF.

[0039] The water detection sensor 50 is located in the auxiliary equipment 36 as one of the sensors arranged inside the battery case 12. The water detection sensor 50 is equipped with a pair of electrodes 54 that protrude downward from the sensor body 52, and each of the electrodes 54 protrudes from the sensor body 52 toward the lower part 24B of the bottom plate 24.

[0040] The pair of electrodes 54 are either the same length or one is longer than the other. In the water detection sensor 50, for example, electrode 54A is longer than electrode 54B. As a result, the water detection sensor 50 can detect when water has accumulated in the lower part 24B of the bottom plate 24 of the lower case 22 by immersing the respective tips of electrodes 54A and 54B in water W.

[0041] Next, the operation of this embodiment will be described. The battery 10 includes a battery case 12, which consists of an upper case 20 and a lower case 22. In the battery case 12, a battery module 16, which consists of multiple stacked battery cells, is placed (fixed) on the lower case 22 and covered by the upper case 20. Thus, the battery 10 houses the battery module 16 (battery pack 14) inside the battery case 12.

[0042] In battery 10, each of the multiple battery cells in battery module 16 is charged when DC power of the required voltage is input. In addition, battery 10 outputs DC power of the required voltage once the battery cells are charged.

[0043] In such a battery 10, the battery performance deteriorates when water W adheres to or is submerged in the battery cells or the battery module 16 in which the battery cells are stacked. Therefore, in order to suppress the deterioration of battery performance, it is necessary to prevent water W from adhering to or being submerged in the battery module 16.

[0044] The battery 10 has a battery case 12 mounted on the underside of the vehicle. In a vehicle, there is a possibility that rainwater accumulated on the road surface may come into contact with the battery case 12 while driving, or that the battery case 12 may become submerged in rainwater accumulated on the road surface. In the case of the battery 10, water W seeps into the battery case 12 and accumulates on the bottom plate 24 of the lower case 22.

[0045] In the lower case 22, the peripheral edge of the bottom plate 24 is designated as the lower portion 24B, and this lower portion 24B is lower than the upper surface 24A on which the battery module 16 is mounted. In addition, a stand portion 18 is positioned on the upper surface 24A of the lower case 22, and the battery module 16 is positioned on the stand portion 18.

[0046] Therefore, in the battery 10, even if water W enters the battery case 12, this water W accumulates in the lower part 24B of the bottom plate 24, thus preventing the water W from adhering to the battery module 16 or the battery module 16 from being submerged in water W.

[0047] On the other hand, as shown in Figures 2 and 3, in the lower case 22, a recess 40 is formed in the lower part 24B of the bottom plate 24, and the recess 40 increases the volume in the vicinity of the lower part 24B inside the lower case 22. Therefore, in the battery case 12, the amount of water W that accumulates before reaching the battery module 16 can be increased compared to the case where the recess 40 is not formed in the lower part 24B. As a result, even if water enters the inside of the battery case 12, it is possible to effectively prevent this water W from adhering to the battery module 16 or the battery module 16 from being submerged in water W.

[0048] Furthermore, in vehicles, the rear of the vehicle is often lower than the front of the vehicle depending on the number of passengers and the amount of luggage loaded. In the lower case 22, the recess 40 is formed on the rear side of the vehicle, which can more effectively prevent water W from adhering to the battery module 16 or the battery module 16 from being submerged in water W.

[0049] Furthermore, when the vehicle is steered, an inertial force is generated in the vehicle width direction. For this reason, the amount of water near the left and right corners 44LB and 44RB of the lower case 22 tends to increase (the change is large). However, the recesses 40 are formed near these corners 44LB and 44RB. This allows the battery case 12 to more effectively prevent water W from adhering to the battery modules 16 or the battery modules 16 from becoming submerged in water W.

[0050] Furthermore, in the event of a vehicle emergency, the vehicle may be subjected to a load on the rear side in the longitudinal direction or on the inside in the vehicle width direction. The lower case 22 is formed with a substantially L-shaped recess 40, which forms a bead portion corresponding to the recess 40. This prevents the battery case 12 from being deformed even if the lower case 22 is subjected to a load on the rear side in the longitudinal direction or on the inside in the vehicle width direction in the event of a vehicle emergency. Therefore, the battery case 12 can protect the battery modules 16 in the event of a vehicle emergency, etc.

[0051] Meanwhile, a water detection sensor 50 is disposed in the lower case 22, facing the lower portion 24B of the bottom plate 24 on the front side of the vehicle. The water detection sensor 50 can detect that water W has entered the bottom plate 24 when both of the pair of electrodes 54A, 54B are in contact with or immersed in water W. As a result, even if water W has entered the battery case 12, the water detection sensor 50 can detect this, thereby preventing the battery 10 from being used with water W adhering to the battery modules 16.

[0052] In a vehicle, deceleration generates a forward inertial force, acceleration generates a rearward inertial force, and steering generates a transverse inertial force. In the lower case 22, if water W adheres to the low portion 24B, the water W flows (moves) in response to the inertial force.

[0053] As a result, in the battery case 12, the water detection sensor 50 is disposed on the front side of the vehicle where the recess 40 is not provided, so that the water detection sensor 50 can efficiently detect water W while the vehicle is traveling.

[0054] Additionally, bead portions 60 are formed in the lower case 22 near the corners 44RF and 44LF on the front side of the vehicle. The water detection sensor 50 is disposed near the corner 44RF where the bead portion 60 is formed. As a result, even if the amount of water W that reaches the low portion 24B near the corner 44RF is small, the water detection sensor 50 can efficiently detect the intrusion of water into the battery case 12.

[0055] Furthermore, the lower case 22 has bead portions 60 provided near the corners 44RF, 44LF of the bottom plate 24, and these bead portions 60 are inclined relative to the vehicle longitudinal direction and the vehicle width direction. This allows the battery case 12 to protect the battery modules 16 from loads input from the front or outside in the vehicle width direction in the event of a vehicle emergency, etc.

[0056] In this way, in the battery case 12, the recesses 40 are formed near the corners 44LB, 44RB on the vehicle rear side in the lower case 22. This makes it possible to prevent the battery modules 16 from being submerged in water W compared to when the recesses 40 are not formed in the battery case 12.

[0057] Furthermore, in the battery case 12, beads 60 are formed near the corners 44LB and 44RB on the vehicle front side of the lower case 22, and a water detection sensor 50 is disposed near the corner 44RF. This allows the battery case 12 to effectively detect when water W has entered the interior, and effectively prevents the battery modules 16 from performing charging and discharging operations while submerged in water.

[0058] Furthermore, in the battery case 12, a bead portion is formed on the vehicle rear side of the lower case 22 corresponding to the recessed portion 40, and a bead portion 60 is formed on the vehicle front side. As a result, the battery case 12 can protect the battery module 16 from loads input from the surroundings in the event of a vehicle emergency, etc.

[0059] In the embodiment described above, recesses 40 are formed near the rear corners 44LB and 44RB of the vehicle. However, recesses may also be formed in a substantially straight line in the lower portion 24B between corners 44LB and 44RB, in addition to near corners 44LB and 44RB. Alternatively, recesses may be formed in a substantially straight line from corners 44LB and 44RB toward the front of the vehicle toward the lower portion 24B, in addition to near corners 44LB and 44RB. This increases the amount of water before the battery module 16 is submerged, thereby preventing the battery module 16 from being submerged in water W.

[0060] Furthermore, in the water detection sensor 50, the amount of water W that can be detected changes depending on the distance between the tip of the short electrode 54B and the upper surface of the lower part 24B. From this, the water detection sensor 50 may be configured so that the length of the electrode 54B is set according to the amount of water W to be detected. As a result, the battery case 12 can use the water detection sensor 50 as a water volume detection sensor to detect whether or not the amount of water W has reached a preset amount.

[0061] In this embodiment, the water detection sensor 50 is disposed near the corner 44RF. However, the water detection sensor 50 may be disposed near the corner 44LF, or may be disposed between the corners 44LF and 44RF (at the middle in the vehicle width direction). [Explanation of symbols]

[0062] 10 Battery 12. Battery Case (Vehicle Battery Case, Case Body) 14 Battery pack 16 Battery module (multiple battery cells) 20 Upper case (case body) 22 Lower case (case body) 24 Bottom plate 40 recess 44(44LB, 44LF, 44RB, 44RF) Corner 50 Water detection sensor (water level detection part) 60 Bead section

Claims

1. The battery module includes a case body having a rectangular parallelepiped outer shape and accommodates a battery module having a plurality of stacked battery cells in an internal space, the battery module being placed on the inner surface of a bottom plate, The battery case for a vehicle includes a recess formed in the case body at a corner on the inner surface of the bottom plate, the recess opening upward.

2. The battery case for a vehicle according to claim 1 , wherein the recess is formed in a vehicle rear portion of the bottom plate.

3. The battery case for a vehicle according to claim 1, further comprising: a water level detector provided in the case body for detecting the amount of water accumulated on the bottom plate at the front side of the vehicle.

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