Battery case lower structure

Abstract

To provide a battery case lower structure that achieves both weight reduction and suppression of damage to a cooling structure.SOLUTION: A lower structure of a battery case 10 includes: a case body 11 that houses a battery 2; a cooling mechanism 20 having a passage area 20A in which a refrigerant passage 23 is formed and a non-passage area 20B in which no refrigerant passage is formed and joined to the lower surface of a bottom plate 11a of the case body 11; and an undercover 30 that covers the cooling mechanism 20 from below at a distance from the cooling mechanism 20 and the bottom plate 11a in the vertical direction. A protruding portion 40 protrudes from at least one of a case side facing area 10A that overlaps with the non-passage area 20B in a plan view on the bottom plate 11a of the case body 11, a cover side facing area 30A that overlaps with the non-passage area 20B in a plan view on the undercover 30, and a non-passage area 20B. A protruding height h40 of the protruding portion 40 is greater than a thickness t20 of the cooling mechanism 20.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a lower structure of a battery case. [Background technology]

[0002] When a vehicle is equipped with an electric motor as a power source, the vehicle is equipped with a battery as a power source for the electric motor and a battery case that houses the battery. In many cases, the battery case is placed on the underside of the floor panel and is close to the road surface. On the other hand, against the backdrop of worsening environmental problems such as global warming, efforts to improve the fuel efficiency of vehicles are accelerating. Reducing the weight of the vehicle body and reducing aerodynamic resistance are considered effective in improving fuel efficiency. Reducing the weight of the battery case and improving the aerodynamic performance of its lower structure have the same effect on the vehicle body, contributing to reducing the environmental load. Furthermore, the battery case is also required to be designed as low as possible in order to ensure freedom of layout.

[0003] Patent Document 1 discloses a battery case including a plate-shaped cooler attached to a bottom plate of the case and an undercover that covers the bottom plate and the cooler from below. The undercover is a thin plate material having a uniform thickness. The cooler is fastened to the undercover. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2023-14627 A Summary of the Invention [Problem to be solved by the invention]

[0005] When the battery case comes into contact with the road surface, a load is input to the underside of the undercover. This may cause the undercover to deform upward and come into contact with the cooler, which may damage the cooler. One idea for maintaining a low profile of the battery case and preventing damage to the cooler is to narrow the fastening interval to suppress deformation of the undercover. However, this would increase the number of manufacturing steps and parts for the battery case, leading to an increase in the weight of the battery case.

[0006] An object of the present invention is to provide a lower structure of a battery case that is lightweight and prevents damage to the cooling structure. [Means for solving the problem]

[0007] One aspect of the present invention provides a lower structure for a battery case, comprising: a case body having a bottom plate supporting a vehicle battery and accommodating the battery; a cooling mechanism having a passage area in which a refrigerant passage is formed for flowing a refrigerant for cooling the battery, and a non-passage area in which the refrigerant passage is not formed, the cooling mechanism being formed in a flat shape and joined to an underside of the bottom plate of the case body; an undercover covering the cooling mechanism from below at a distance from the cooling mechanism and the bottom plate in the vertical direction; a case side facing area in the bottom plate of the case body overlapping with the non-passage area in a planar view; a cover side facing area in the undercover overlapping with the non-passage area in a planar view; and a protrusion protruding from at least one of the non-passage area, the case side facing area, and the cover side facing area in a direction narrowing the gap between the undercover and the cooling mechanism or the bottom plate, the protruding height being greater than a thickness of the cooling mechanism.

[0008] According to the above configuration, the protrusion is provided in at least one of the non-passage area of ​​the cooling mechanism, the case-side facing area overlapping the non-passage area in a plan view, or the cover-side facing area overlapping the non-passage area in a plan view. The protrusion height is greater than the thickness of the cooling mechanism. Therefore, for example, when the protrusion is provided in the cover-side facing area, even if a load is input when interfering with the road surface and the undercover is deformed upward, the protrusion hits the non-passage area of ​​the cooling mechanism or the case-side facing area of ​​the bottom plate of the case body first, and it is possible to prevent the passage area of ​​the cooling mechanism from directly contacting the undercover. Even when the protrusion is provided in the non-passage area or the case-side facing area, the protrusion hits the cover-side facing area of ​​the undercover first before the passage area of ​​the cooling mechanism directly contacts the undercover. In this way, by providing the protrusion locally at the location where the non-passage area is formed, it is possible to suppress damage to the cooling mechanism (especially leakage of the refrigerant) while suppressing an increase in weight of the lower structure of the battery case.

[0009] The protrusion may be provided in the non-passage area or the case-side facing area so as to protrude downward.

[0010] According to the above configuration, the passage area can be protected by the protrusion provided on the case body or the cooling mechanism.

[0011] The cooling mechanism may have a through hole as part of the non-passage region, and the protrusion may be provided in the case-side facing region and pass through the through hole to protrude below a lower surface of the cooling mechanism.

[0012] According to the above-mentioned configuration, damage to the passage area caused by contact between the protrusion provided on the case body and the undercover can be suppressed. In addition, direct contact between the non-passage area of ​​the cooling mechanism and the undercover can be avoided, which makes it easier to suppress damage to the cooling mechanism.

[0013] The protrusion may protrude downward from a lower surface of the non-passage area.

[0014] According to the above configuration, damage to the passage area due to contact between the protrusion provided in the non-passage area and the undercover can be suppressed.

[0015] The protrusion may be provided in the cover-side facing region so as to protrude upward.

[0016] According to the above configuration, the passage area can be protected by the protrusion provided on the undercover.

[0017] The undercover may have a substantially flat bottom plate portion and a reinforcing material arranged on an upper surface side of the bottom plate portion, and the protrusion may protrude upward from the reinforcing material of the undercover.

[0018] According to the above-mentioned configuration, the presence of the reinforcing material improves the rigidity of the undercover. Since the undercover is less likely to deform, damage to the cooling mechanism can be further suppressed. The height of the reinforcing material can be utilized to provide a small protrusion.

[0019] The undercover may have a bolt mounting portion through which a bolt is inserted for fastening to the case body, and the bolt mounting portion may be provided so as to protrude upward, independent of the protrusion.

[0020] According to the above-mentioned configuration, since the bolt attachment portion and the protrusion are provided on the reinforcing member, it is easy to form the bottom plate portion flat, and the aerodynamic performance regarding the flow under the floor of the vehicle is improved.

[0021] The protrusion may be frusto-conical in shape.

[0022] According to the above configuration, the protrusion can be made small while protecting the passage area, and the battery case can be made lighter.

[0023] The lower surface of the cover-side facing region may be flat.

[0024] According to the above configuration, the aerodynamic performance regarding the flow under the floor of the vehicle is improved. Effect of the Invention

[0025] According to the present invention, it is possible to provide a lower structure of a battery case that achieves both weight reduction and suppression of damage to the cooling structure. [Brief description of the drawings]

[0026] [Figure 1] 1 is a side view of a vehicle equipped with a battery case according to a first embodiment. [Diagram 2] FIG. 2 is an exploded perspective view of the battery case according to the first embodiment. [Diagram 3] FIG. 2 is an exploded perspective view of the lower structure of the battery case according to the first embodiment. [Figure 4] FIG. 2 is a cross-sectional view of the battery case according to the first embodiment. [Diagram 5] FIG. 11 is an exploded perspective view of the lower structure of the battery case according to the second embodiment. [Figure 6] FIG. 11 is an exploded perspective view of a cooling mechanism according to a second embodiment. [Figure 7] FIG. 11 is a cross-sectional view of a cooling mechanism according to a second embodiment. [Figure 8] FIG. 11 is a cross-sectional view of a battery case according to a second embodiment. [Figure 9] FIG. 11 is an exploded perspective view of a cooling mechanism according to a third embodiment. [Figure 10] FIG. 11 is a cross-sectional view of a cooling mechanism according to a third embodiment. [Figure 11] FIG. 13 is a cross-sectional view of a battery case according to a fourth embodiment. [Figure 12] FIG. 13 is a perspective view of an undercover according to a fifth embodiment. [Figure 13] FIG. 13 is a cross-sectional view of a battery case according to a fifth embodiment. [Figure 14] FIG. 13 is a perspective view of an undercover according to a sixth embodiment. [Figure 15] FIG. 13 is a cross-sectional view of a battery case according to a sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, an embodiment will be described with reference to the drawings. Note that the same or corresponding elements are designated by the same reference numerals throughout the drawings, and detailed description thereof will be omitted.

[0028] (First embodiment) With reference to FIG. 1, automobile 1 is an electric vehicle that runs by driving a motor with power supplied from a battery 2. Automobile 1 is a vehicle that runs on electricity, and may be, for example, an electric vehicle or a plug-in hybrid vehicle. The type of vehicle is not particularly limited, and may be a passenger car, a truck, a work vehicle, or other mobility. In the following, a passenger car type electric vehicle will be described as an example of an electric vehicle.

[0029] The automobile 1 is equipped with an electric motor and high-voltage equipment (not shown) in the front part 3 of the vehicle. The automobile 1 also has an automobile battery case 10 that houses a battery 2, which occupies almost the entire area under the floor of the passenger compartment 5 in the center part 4 of the vehicle.

[0030] In Fig. 1, the front-rear direction (vehicle length direction) of the automobile 1 is indicated as the X direction, and the up-down direction (vehicle height direction) is indicated as the Z direction. The same notation is used in the subsequent figures, and in Fig. 2 and onwards, the left-right direction (vehicle width direction) of the automobile 1 is indicated as the Y direction.

[0031] Referring to FIG. 2, the battery case 10 includes a case body 11, a cross member 12, an energy absorbing material (hereinafter, EA material 13), an upper cover 14, a cooling mechanism 20, and an undercover 30.

[0032] The case body 11 has a bottom plate 11a and a peripheral wall 11b erected on the peripheral edge of the bottom plate 11a. The case body 11 may be formed by drawing a metal sheet. The case body 11 may be constructed by joining the bottom plate 11a formed of a flat plate material and the peripheral wall 11b formed of an extruded material. The material of the case body 11 is not particularly limited, and may be steel, aluminum alloy, or resin, or may be a composite material of metal and resin.

[0033] The bottom plate 11a is flat and, for example, rectangular in plan view. When mounted on the automobile 1 (see FIG. 1), the long side of the bottom plate 11a faces the vehicle length direction, and the short side of the bottom plate 11a faces the vehicle width direction. The peripheral wall 11b includes a front wall, a rear wall, and a pair of side walls 11c. The pair of side walls 11c extend upward in the vehicle length direction from a pair of side edges (long side edges in this example) of the bottom plate 11a, respectively.

[0034] The case body 11 forms an accommodation space 11d defined by the upper surface of the bottom plate 11a and the inner peripheral surface of the peripheral wall 11b, and the accommodation space 11d is widely open on the upper side. A plurality of (e.g., three) cross members 12 are arranged in the accommodation space 11d. In this embodiment, the plurality of cross members 12 are arranged at intervals in the vehicle length direction, extend parallel to each other in the vehicle width direction, and both ends of each cross member 12 are joined to the inner peripheral surface of each of the pair of side walls 11c. The accommodation space 11d is partitioned by the plurality of cross members 12 into a plurality of rooms aligned in the vehicle length direction. The battery 2 (see FIG. 1) is accommodated in the accommodation space 11d (more specifically, divided into a plurality of rooms partitioned by the cross members 12) and supported on the upper surface of the bottom plate 11a.

[0035] The EA material 13 extends in the vehicle length direction. The EA material 13 forms a pair in the vehicle width direction and is respectively joined to the outer surfaces of a pair of side walls 11c of the case body 11. Although detailed illustration is omitted, the pair of EA materials 13 are attached to a pair of side sills constituting the vehicle body frame, so that the battery case 10 is disposed under the floor and supported by the vehicle body frame. The EA material 13 is crushed together with the side sills during a side collision to absorb the collision energy and protect the case body 11 and the battery 2 (see FIG. 1) accommodated therein. The EA material 13 may be constituted by an extrusion material having a plurality of closed cross sections extending in the vehicle length direction and aligned in the vehicle width direction.

[0036] The top cover 14 is fastened to the upper end surface of the peripheral wall 11b to close the storage space 11d. A gasket (not shown) may be interposed between the top cover 14 and the case body 11 to ensure watertightness of the storage space 11d.

[0037] The case body 11 (particularly, the bottom plate 11a), the cooling mechanism 20, and the undercover 30 constitute the lower structure of the battery case 10. The cooling mechanism 20 is formed in a flat plate shape overall, and is joined to the lower surface of the bottom plate 11a of the case body 11. The undercover 30 is disposed at a distance from the cooling mechanism 20 and the bottom plate 11a in the up-down direction, and covers the cooling mechanism 20 from below.

[0038] 2 and 3, the cooling mechanism 20 includes an upper plate 21 and a lower plate 22 stacked on top of each other in the vertical direction. The upper plate 21 and the lower plate 22 have substantially the same shape in a plan view. The upper plate 21 and the lower plate 22 are formed from a metal plate material. From the viewpoints of thermal conductivity, strength, weight, and the like, aluminum alloy, steel, and copper are suitable examples of this metal material.

[0039] The lower plate 22 has one groove recessed in its upper surface. The groove extends in a serpentine manner within the lower plate 22. The upper plate 21 is placed on the upper surface of the lower plate 22 and joined to the lower plate 22 by a joining means such as adhesive. This closes the groove and forms the refrigerant passage 23. The refrigerant passage 23 is formed inside the cooling mechanism 20 and is configured as a single system from one end to the other end. An inlet 24a is provided at one end of the refrigerant passage 23 for allowing the refrigerant to flow into the refrigerant passage 23, and an outlet 24b is provided at the other end of the refrigerant passage 23 for allowing the refrigerant to flow out of the refrigerant passage 23.

[0040] Although detailed illustration is omitted, the automobile (see FIG. 1) is provided with an external flow path (not shown) that connects the inlet 24a and the outlet 24b outside the battery case 10. The external flow path and the refrigerant passage 23 form a closed circuit that circulates the refrigerant. A cooling pump (not shown) that pressurizes and circulates the refrigerant, and a radiator that dissipates heat from the refrigerant are interposed in the external flow path.

[0041] As an example, the upper surface of the upper plate 21 is bonded to the lower surface of the bottom plate 11a of the case body 11, thereby assembling the cooling mechanism 20 to the case body 11. As the refrigerant flows through the refrigerant passage 23, it exchanges heat with the battery 2 (see FIG. 1) in the case body 11 by solid-state heat transfer via the upper plate 21 of the cooling mechanism 20 and the bottom plate 11a of the case body 11. This allows the battery 2 to be cooled and maintained at an appropriate temperature. The upper surface of the upper plate 21, i.e., the upper surface of the cooling mechanism 20 as a whole, is flat. The contact area of ​​the cooling mechanism 20 with the bottom plate 11a of the case body 11 is as large as possible, thereby improving the cooling performance of the cooling mechanism 20.

[0042] The cooling mechanism 20 has a plurality of through holes 20a arranged in the vehicle length direction. The through holes 20a extend from the upper surface of the upper plate 21 to the lower surface of the lower plate 22. The number of through holes 20a is the same as that of the cross members 12. When the cooling mechanism 20 is installed in the case body 11, each through hole 20a extends in the vehicle width direction and overlaps with a corresponding one of the cross members 12 in a plan view. In the case body 11, since the battery 2 (see FIG. 1) is not present in the location where the cross member 12 is arranged, even if a refrigerant passage 23 is formed in the area overlapping with the cross member 12 in a plan view, the refrigerant does not contribute to cooling the battery 2 when flowing through the area. By providing the through holes 20a in the area, it is possible to achieve both weight reduction of the cooling mechanism 20 and maintenance of cooling performance.

[0043] The cooling mechanism 20 is roughly divided into a passage region 20A in which the refrigerant passage 23 is formed, and a non-passage region 20B in which the refrigerant passage 23 is not formed in a plan view. The refrigerant passage 23 is not formed in the peripheral portion of the cooling mechanism 20. The peripheral portion is the non-passage region 20B.

[0044] The refrigerant passage 23 is formed in a rectangular region inside the peripheral portion. However, the entire rectangular region is not a passage region. The passage regions 20A and non-passage regions 20B are arranged alternately in the vehicle length direction within the rectangular region. The aforementioned through holes 20a correspond to the non-passage regions 20B within the rectangular region. On the other hand, the accommodation space 11d is divided into a plurality of rooms by the cross member 12, and the plurality of passage regions 20A overlap each of the plurality of rooms in a plan view.

[0045] In each passage area 20A, a plurality of non-passage areas 20B are distributed and arranged. Each non-passage area 20B is circular in plan view. In each passage area 20A, the plurality of non-passage areas 20B are arranged at intervals from each other in the vehicle width direction. The plurality of non-passage areas 20B may be arranged along a straight line extending in the vehicle width direction (see the two passage areas 20A near the center in the vehicle length direction), or may be arranged in a staggered manner so as to shift positions in the vehicle length direction (see the two passage areas 20A near both ends in the vehicle length direction).

[0046] 2 and 3, the undercover 30 has a bottom plate portion 31 that covers the cooling mechanism 20 from below, and a flange portion 32 provided on the periphery of the bottom plate portion 31. The bottom plate portion 31 has a rectangular shape in a plan view. Similar to the bottom plate 11a of the case main body 11, when the battery case 10 is mounted on the automobile 1 (see FIG. 1), the long side of the bottom plate portion 31 extends in the vehicle length direction, and the short side extends in the vehicle width direction.

[0047] The flange portion 32 is provided around the entire periphery of the bottom plate portion 31 and has a rectangular window frame shape in a plan view. A plurality of screw insertion holes 32a are provided at intervals in the flange portion 32. Each screw insertion hole 32a penetrates the flange portion 32 in the up-down direction. Although detailed illustration is omitted, the upper surface of the flange portion 32 is in surface contact with the peripheral portion of the lower surface of the bottom plate 11a of the case body 11. A bolt (not shown) is inserted from below into the screw insertion hole 32a and screwed into the bottom plate 11a of the case body 11. In this way, the undercover 30 is joined to the case body 11.

[0048] The bottom plate portion 31 of the undercover 30 is also joined to the case body 11. The joining here is a point joining, and is a removable joining. As an example, fastening with bolts 41 is a suitable example of joining the bottom plate portion 31 to the case body 11. The bottom plate portion 31 has a plurality of joining points 35 for joining to the case body 11. The joining points 35 are provided with bolt mounting portions 39. Bolts are inserted into the bolt mounting portions 39 to fasten the undercover 30 to the case body 11. The bolt mounting portions 39 are provided on the undercover 36 so as to protrude upward, independent of the protruding portions 40.

[0049] When the undercover 30 is attached to the case body 11 , the bottom plate portion 31 is disposed lower than the lower surface of the bottom plate 11 a and the lower surface of the cooling mechanism 20 .

[0050] Here, the "case side facing region 10A" refers to a region in the bottom plate 11a of the case body 11 that overlaps with the non-passage region 20B of the cooling mechanism 20 in a plan view when the cooling mechanism 20 and the undercover 30 are assembled to the case body 11. The "cover side facing region 30A" refers to a region in the undercover 30 (particularly, the bottom plate portion 31) that overlaps with the non-passage region 20B of the cooling mechanism 20 in a plan view when the cooling mechanism 20 and the undercover 30 are assembled to the case body 11.

[0051] A protrusion 40 is provided in the lower structure of the battery case 10. The protrusion 40 is provided in at least one of the cover-side facing region 30A of the undercover 30, the non-passage region 20B of the cooling mechanism 20, and the case-side facing region 10A of the bottom plate 11a of the case body 11. The protrusion 40 protrudes in the vertical direction, particularly in the direction that narrows the gap between the undercover 30 and the cooling mechanism 20 or the bottom plate 11a. On the other hand, the plate thickness direction of the cooling mechanism 20 is also oriented in the vertical direction.

[0052] A protruding height h40 of the protruding portion 40 is greater than a thickness t20 of the cooling mechanism 20. The upper surface of the upper plate 21 of the cooling mechanism 20 is flat, while the lower surface side of the lower plate 22 of the cooling mechanism 20 protrudes downward at the portion where the groove is formed relative to other portions. The "thickness t20" is the dimension from the upper surface of the upper plate 21 to the lower end of the lower plate 22 (the downward protruding end for forming the groove) in the normal direction to the upper surface of the upper plate 21.

[0053] 2 and 3, in the first embodiment, the protrusion 40 is provided in the cover-side facing region 30A of the undercover 30. No protrusion is provided in the non-passage region 20B and the case-side facing region 10A.

[0054] A plurality of protrusions 40 are provided on the bottom plate portion 31. The protrusions 40 are in the shape of a truncated cone with a smaller diameter toward the top, and protrude upward from the upper surface of the bottom plate portion 31. The protrusions 40 are relatively small in comparison with the overall size of the bottom plate portion 31. The point-like protrusions 40 are distributed and arranged in the cover-side facing region 30A of the bottom plate portion 31. In the first embodiment, the "protrusion height h40" is the vertical dimension from the upper surface of the bottom plate portion 31 (particularly, the upper surface of the portion where the protrusions 40 or the joint points 35 are not provided) to the upper end of the protrusion 40 (the top surface in this example, which is a truncated cone).

[0055] The protrusion 40 is provided in the cover-side facing region 30A, and since the cover-side facing region 30A overlaps with the non-passage region 20B in a planar view, the protrusion 40 overlaps with the non-passage region 20B in a planar view. The multiple protrusions 40 correspond one-to-one to the multiple non-passage regions 20B scattered within each passage region 20A, and each protrusion 40 is arranged so as to overlap with a corresponding one non-passage region 20B in a planar view.

[0056] 4, according to the above configuration, even if a load is input to the undercover 30 when it comes into contact with the road surface and the undercover 30 is deformed upward, the protrusion 40 hits the non-passage area 20B of the cooling mechanism 20 or the case-side facing area 10A of the bottom plate 11a of the case body 11 first. This makes it possible to prevent the passage area 20A of the cooling mechanism 20 from directly contacting the undercover 30, thereby preventing damage to the refrigerant passage 23. The protrusion 40 is provided locally at a location corresponding to the non-passage area 20B. This makes it possible to suppress damage to the cooling mechanism 20 (especially leakage of the refrigerant) while suppressing an increase in weight of the lower structure of the battery case 10.

[0057] The protrusion 40 has a truncated cone shape. The protrusion 40 can be made small, which makes it easier to maintain the weight of the battery case 10. In addition, the non-passage area 20B corresponding to the protrusion 40 is also made small, which makes it possible to maintain high cooling performance of the cooling mechanism 20.

[0058] The protruding portion 40 protrudes upward from the bottom plate portion 31, while the lower surface of the cover-side facing region 30A is flat. Even if the undercover 30 as a whole has vertical irregularities due to the provision of the protruding portion 40, it is possible to maintain high aerodynamic performance regarding the flow under the floor of the vehicle.

[0059] Second embodiment Next, the lower structure of the battery case 10 according to the second embodiment will be described with reference to Figures 5 to 8, focusing on the differences from the first embodiment. As shown in Figure 5, in the second embodiment, the protrusion 40 is omitted from the undercover 30 and is provided in the non-passage area 20B of the cooling mechanism 20.

[0060] Similar to the first embodiment, a plurality of non-passage regions 20B are interspersed in the passage region 20A of the cooling mechanism 20. A plurality of protrusions 40 correspond one-to-one to the plurality of non-passage regions 20B, and each protrusion 40 protrudes downward in the corresponding non-passage region 20B.

[0061] In the second embodiment, the "protrusion height h40" is the dimension from the upper surface of the upper plate 21 to the lower end of the protrusion 40 in the normal direction (vertical direction) of the upper surface of the upper plate 21. The "thickness t20" is defined in the same manner as in the first embodiment. The protrusion height h40 is greater than the thickness t20. In other words, the lower end of the protrusion 40 is located lower than the downward protruding end at the portion where the groove is formed.

[0062] In this embodiment, the protruding portion 40 is provided on the upper plate 21 (see FIG. 6). The lower plate 22 is provided with a through hole 22a for allowing the protruding portion 40 to pass therethrough and protrude downward beyond the lower plate.

[0063] According to the above configuration, even if a load is input to the undercover 30 when it comes into contact with the road surface and the undercover 30 is deformed upward as a result, the protrusion 40 hits the upper surface of the cover-side facing region of the bottom plate portion 31 of the undercover 30 before the passage region 20A of the cooling mechanism 20 comes into direct contact with the undercover 30. Therefore, similar to the first embodiment, it is possible to achieve both weight reduction of the lower structure of the battery case 10 and suppression of damage to the cooling mechanism 20. Since the protrusion 40 is not provided on the undercover 30, it is easy to form the lower surface of the undercover 30 flat, which makes it easy to further improve aerodynamic performance.

[0064] Third embodiment Next, with reference to Figs. 9 and 10, the lower structure of the battery case 10 according to the third embodiment will be described, focusing on the differences from the first and second embodiments.

[0065] In this embodiment, as in the second embodiment, the protrusions 40 are provided in the non-passage area 20B of the cooling mechanism 20. The installation positions and number of the protrusions 40 are also the same as in the second embodiment. Unlike the second embodiment, in this embodiment, the protrusions 40 are provided on the lower plate 22. The protrusions 40 are formed by recessing the lower plate 22 downward from the upper surface. An upper end opening of the protrusions 40 is formed on the upper surface of the lower plate 22 in addition to the groove, but this upper end opening is closed by the upper plate 21.

[0066] In this embodiment as well, it is possible to simultaneously reduce the weight of the lower structure of the battery case 10 and prevent damage to the cooling mechanism 20. In addition, aerodynamic performance can be easily improved.

[0067] (Fourth embodiment) Next, with reference to FIG. 11, the lower structure of the battery case 10 according to the fourth embodiment will be described, focusing on the differences from the first to third embodiments.

[0068] In this embodiment, unlike the first to third embodiments, the protruding portion 40 is provided in the case side facing region 10A of the bottom plate 11a of the case body 11. The protruding portion 40 passes through the through hole 20b formed in the cooling mechanism 20 and protrudes downward from the lower end of the cooling mechanism 20. The through hole 20b is a hole that penetrates from the upper surface of the upper plate 21 to the lower surface of the lower plate 22, and is formed in the non-passage region 20B. In the fourth embodiment, the "protruding height h40" is the dimension from the lower surface of the bottom plate 11a to the lower end of the protruding portion 40. The lower surface of the bottom plate 11a is in surface contact with the upper surface of the upper plate 21 of the cooling mechanism 20, and the protruding height h40 is larger than the thickness t20 of the cooling mechanism 20. That is, the lower end of the protruding portion 40 is located lower than the downward protruding end at the portion where the groove of the lower plate 22 is formed.

[0069] In this embodiment as well, it is possible to simultaneously reduce the weight of the lower structure of the battery case 10 and prevent damage to the cooling mechanism 20. In addition, aerodynamic performance can be easily improved.

[0070] Fifth embodiment Next, with reference to Figs. 12 and 13, the lower structure of the battery case 10 according to the fifth embodiment will be described, focusing on the differences from the first to fourth embodiments.

[0071] In this embodiment, the undercover 30 has a reinforcing member 36 arranged on the upper surface side of the bottom plate portion 31. The reinforcing member 36 is prepared as a separate part from the base part 33 that originally forms the bottom plate portion 31 and the flange portion 32, and is joined to this base part 33 by joining means such as welding to form an integrated undercover 30 together with the base part 33. In the first to fourth embodiments, the undercover 30 is formed of a single base part 33. In this way, the provision of the reinforcing member 36 increases the rigidity of the undercover 30, so that even if a load is input to the undercover 30 when it interferes with the road surface, the undercover 30 is less likely to deform. Therefore, damage to the cooling mechanism 20 is suppressed.

[0072] The reinforcing member 36 according to the present embodiment has a plurality of band plate portions 37 extending in the vehicle width direction and a plurality of raised portions 38 extending in the vehicle width direction, and the plurality of band plate portions 37 and the plurality of raised portions 38 are arranged so as to be alternately arranged in the vehicle length direction. The band plate portion 37 overlaps with the passage area 20A in a plan view, and the raised portions 38 overlap with the non-passage area 20B in a plan view. The upper surface of the raised portions 38 is located above the upper surface of the band plate portion 37. The lower surface of the band plate portion 37 is in surface contact with the upper surface of the bottom plate portion 31. The raised portions 38 are provided with bolt attachment portions 39 that define the joint points 35. A bolt 41 is inserted into the bolt attachment portion 39 to fasten the undercover 30 and the case body 11. The bolt attachment portion is provided on the reinforcing member 36 so as to protrude upward, independent of the protruding portion 40. In order to enable the bolts 41 applied to the joints 35 to be inserted and removed from the underside of the base component 33, the bottom plate portion 31 (base component 33) is appropriately provided with holes 33a for installing screws.

[0073] In this embodiment, the protrusions 40 are provided on the undercover 30, similarly to the first embodiment, and the installation positions and number of the protrusions 40 are also similar to the first embodiment. Unlike the first embodiment, the protrusions 40 are provided on the reinforcing material 36. The protrusions 40 protrude upward from the reinforcing material 36.

[0074] In this manner, the reinforcing material 36 according to the present embodiment covers most of the upper surface of the bottom plate portion 31 from above. Therefore, a large portion of the passage region 20A of the cooling mechanism 20 overlaps with the reinforcing material 36 in a plan view. In the fifth embodiment, the "protrusion height h40" is the dimension from the upper surface of the reinforcing material 36 (particularly, the band plate portion 37) to the upper end of the protrusion 40. This protrusion height h40 is greater than the thickness t20 of the cooling mechanism 20.

[0075] In this embodiment as well, it is possible to achieve both weight reduction of the lower structure of the battery case 10 and suppression of damage to the cooling mechanism 20. Furthermore, when providing the protrusion 40 on the undercover 30, the protrusion 40 is provided on the reinforcing material 36, which is a separate component from the base component 33 that forms the bottom plate portion 31. This makes it easy to form the lower surface of the bottom plate portion 31 flat, which makes it easy to improve aerodynamic performance.

[0076] Sixth embodiment Next, with reference to Figs. 14 and 15, the lower structure of the battery case 10 according to the sixth embodiment will be described, focusing on the differences from the first to fifth embodiments.

[0077] In this embodiment, the undercover 30 has a base part 33 that forms the bottom plate portion 31, and a reinforcing member 36 provided on the upper surface side of the bottom plate portion 31, similarly to the fifth embodiment. In this embodiment, unlike the fifth embodiment, the reinforcing member 36 does not have a raised portion. Instead, a plurality of reinforcing members 36 are arranged at intervals in the vehicle length direction, and the plurality of reinforcing members 36 according to this embodiment corresponds to the plurality of band plate portions according to the fifth embodiment.

[0078] In this embodiment, unlike the fifth embodiment, most of the passage region 20A of the cooling mechanism 20 overlaps with the upper surface of the bottom plate portion 31 in a plan view. Therefore, in the sixth embodiment, the protrusion height h40 is the dimension from the upper surface of the bottom plate portion 31 to the upper end of the protrusion 40, similar to the first embodiment, regardless of the presence of the reinforcing member 36. This protrusion height h40 is greater than the thickness t20 of the cooling mechanism 20.

[0079] In this embodiment as well, it is possible to achieve both weight reduction of the lower structure of the battery case 10 and suppression of damage to the cooling mechanism 20. Furthermore, when providing the protruding portion 40 on the undercover 30, it is easy to form the lower surface of the bottom plate portion 31 flat, which makes it easy to improve aerodynamic performance. Since the reinforcing material 36 is provided, the undercover 30 is less likely to deform, which further suppresses damage to the cooling mechanism 20.

[0080] (Modification) Although the embodiment has been described above, the above configuration can be appropriately modified, added, or deleted within the scope of the spirit of the present invention.

[0081] In each of the above-mentioned embodiments, the cooling mechanism 20 is composed of two plates, an upper plate 21 and a lower plate 22. The cooling mechanism 20 may be composed of the lower plate 22 and the bottom plate 11a of the case body 11, or the upper plate 21 may be omitted. In this case, a groove is formed on the upper surface side of the lower plate 22, and the groove is closed by the lower surface of the bottom plate 11a to form a refrigerant passage. Brazing can be suitably applied to join the lower plate to the bottom plate 11a. The protrusion 40 is provided so as to protrude upward from the undercover 30. As a result, the same effect as the above-mentioned embodiment can be obtained without creating unevenness in the bottom plate 11a.

[0082] The present disclosure may include the following aspects. (Aspect 1) A case body having a bottom plate for supporting a vehicle battery and accommodating the battery; a cooling mechanism having a passage area in which a refrigerant passage for passing a refrigerant for cooling the battery is formed, and a non-passage area in which the refrigerant passage is not formed, the cooling mechanism being formed in a flat plate shape and joined to a lower surface of a bottom plate of the case body; an undercover that covers the cooling mechanism from below at a distance from the cooling mechanism and the bottom plate in the up-down direction; a case side facing area that overlaps with the non-passage area in a plan view in the bottom plate of the case main body; a cover-side opposing region that overlaps with the non-passage region in a plan view in the undercover; a protruding portion that protrudes from at least one of the non-passage region, the case side facing region, and the cover side facing region in a direction narrowing the gap between the undercover and the cooling mechanism or the bottom plate, and has a protruding height greater than a thickness of the cooling mechanism; The lower structure of the battery case is provided with: (Aspect 2) The protrusion is provided in the non-passage area or the case side facing area so as to protrude downward. A lower structure of the battery case described in embodiment 1. (Aspect 3) the cooling mechanism has a through hole as part of the non-passage region; the protruding portion is provided in the case side facing region, passes through the through hole, and protrudes downward below a lower surface of the cooling mechanism; A lower structure of the battery case according to embodiment 2. (Aspect 4) The protrusion protrudes downward from the lower surface of the non-passage area. A lower structure of the battery case according to embodiment 2. (Aspect 5) The protrusion is provided in the cover-side facing region so as to protrude upward. A lower structure of the battery case described in embodiment 1. (Aspect 6) The undercover has a substantially flat bottom plate portion and a reinforcing material disposed on an upper surface side of the bottom plate portion, The protruding portion protrudes upward from the reinforcing material of the undercover. A lower structure of a battery case according to embodiment 5. (Aspect 7) the undercover has a bolt attachment portion through which a bolt is inserted for fastening to the case body, The bolt attachment portion is provided on the reinforcing material so as to protrude upward, independent of the protrusion. A lower structure of a battery case according to any one of aspects 1 to 6. (Aspect 8) The protrusion is frustoconical in shape. A lower structure of a battery case according to any one of aspects 1 to 7. (Aspect 9) The lower surface of the cover-side facing region is flat. A lower structure of a battery case according to any one of embodiments 1 to 8. [Explanation of symbols]

[0083] 1. Automobiles 2 Battery 3. Front of vehicle 4. Center of vehicle 5 Cabin 10 Battery case 10A Case side facing area 11 Case body 11a Bottom plate 11b Surrounding wall 11c side wall 11d Containment Space 12 Cross member 13 EA materials 14 Top lid 20 Cooling mechanism 20A aisle area 20B Non-passage area 20a through hole 20b passing hole 21 Upper Board 22 Lower plate 22a Through hole 23 Refrigerant passage 24a Inlet 24b Outlet 30 Undercover 30A Cover side facing area 31 Bottom plate part 32 Flange section 32a Screw insertion hole 33 Base parts 33a hole 35 Junction 36 Reinforcement 37 Band part 38 Raised section 39 Bolt mounting part 40 Protrusion 41 Volts h40 (protrusion 40) protrusion height t20 (thickness of cooling mechanism 20)

Claims

1. A case body having a bottom plate for supporting a vehicle battery and accommodating the battery; a cooling mechanism having a passage area in which a refrigerant passage for passing a refrigerant for cooling the battery is formed, and a non-passage area in which the refrigerant passage is not formed, the cooling mechanism being formed in a flat plate shape and joined to a lower surface of a bottom plate of the case body; an undercover that covers the cooling mechanism from below at a distance from the cooling mechanism and the bottom plate in the up-down direction; a case side facing area that overlaps with the non-passage area in a plan view in the bottom plate of the case main body; a cover-side opposing region that overlaps with the non-passage region in a plan view in the undercover; a protruding portion that protrudes from at least one of the non-passage region, the case side facing region, and the cover side facing region in a direction narrowing the gap between the undercover and the cooling mechanism or the bottom plate, and has a protruding height that is greater than a thickness of the cooling mechanism; The lower structure of the battery case is provided with:

2. The protrusion is provided in the non-passage area or the case side facing area so as to protrude downward. The lower structure of a battery case according to claim 1 .

3. the cooling mechanism has a through hole as part of the non-passage region; the protruding portion is provided in the case side facing region, passes through the through hole, and protrudes downward below a lower surface of the cooling mechanism; The lower structure of a battery case according to claim 2.

4. The protrusion protrudes downward from the lower surface of the non-passage area. The lower structure of a battery case according to claim 2.

5. The protrusion is provided in the cover-side facing region so as to protrude upward. The lower structure of a battery case according to claim 1 .

6. The undercover has a substantially flat bottom plate portion and a reinforcing material disposed on an upper surface side of the bottom plate portion, The protruding portion protrudes upward from the reinforcing material of the undercover. The lower structure of a battery case according to claim 5.

7. the undercover has a bolt attachment portion through which a bolt is inserted for fastening to the case body, The bolt attachment portion is provided so as to protrude upward, independently of the protruding portion. The lower structure of a battery case according to any one of claims 1 to 6.

8. The protrusion is frustoconical in shape. The lower structure of a battery case according to any one of claims 1 to 6.

9. The lower surface of the cover-side facing region is flat. The lower structure of a battery case according to any one of claims 1 to 6.

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