Automotive battery case

Abstract

To secure high battery protection performance against an impact in a vehicle fore and aft direction with a simple structure in a battery case for a motor vehicle.SOLUTION: A battery case 100 for a motor vehicle includes: an under cover 140 which is a tray shaped press molding item, has a housing part 141 for housing a battery, and includes lower surface protruding parts 143 provided on a lower surface 142 of the housing part 141, extending from a front end to a rear end in a vehicle fore and aft direction, and protruding upward; and lower surface vertical reinforcement materials 160 each of which extends from a front end to a rear end of the under cover 140 in the vehicle fore and aft direction along the lower surface protruding part 143 below the under cover 140 and is disposed so as to be at least partially housed in the lower surface protruding part 143.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a battery case for automobiles.

Background Art

[0002] In automobiles equipped with a large-capacity battery such as an electric vehicle, the battery is stored in a battery case and arranged under the passenger compartment. In such an automobile battery case, high sealing performance to prevent water intrusion from the road surface and high battery protection performance during an automobile collision are required.

[0003] Patent Documents 1 to 3 disclose automobile battery cases that store a battery in a tray-shaped case to ensure high sealing performance and ensure high battery protection performance by the shape of the case and reinforcing members.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] All of the automobile battery cases of Patent Documents 1 to 3 emphasize the battery protection performance against impacts in the vehicle width direction, and there is room for improvement in the battery protection performance against impacts in the vehicle longitudinal direction. In addition, the structure is complex, and there is room for improvement in terms of making the structure simpler.

[0006] The present invention aims to provide a simple structure that ensures high battery protection performance against impacts in the front-to-rear direction of a vehicle in an automotive battery case. [Means for solving the problem]

[0007] The present invention provides an automobile battery case comprising: an under cover which is a tray-shaped press-formed product and has a storage portion for housing a battery, and a lower surface protrusion portion which extends from the front end to the rear end in the vehicle longitudinal direction and protrudes upward from the lower surface of the storage portion; and a lower surface vertical reinforcing member which extends from the front end to the rear end of the under cover along the lower surface protrusion portion below the under cover and is arranged so as to be at least partially housed in the lower surface protrusion portion.

[0008] This configuration allows for a load transmission path in the longitudinal direction of the vehicle through the underside overhang, ensuring high battery protection against impacts in the longitudinal direction with a simple structure. Specifically, the underside overhang improves load-bearing capacity compared to a simple flat plate, allowing for the transmission of greater loads. Furthermore, since the underside longitudinal reinforcing members are at least partially housed in the underside overhang, space can be utilized efficiently. In addition, the under cover, being a press-formed product made from a single metal plate, does not have seams like joints, thus preventing water from entering from the road surface and ensuring high sealing performance.

[0009] The under cover and the lower vertical reinforcing member may be joined to each other.

[0010] With this configuration, the under cover and the lower vertical reinforcement can bear the load as a single unit, thus ensuring even higher battery protection against impacts in the front-to-rear direction of the vehicle.

[0011] The aforementioned automobile battery case may further include a flat bottom plate positioned below the under cover and the lower vertical reinforcing member, and the lower vertical reinforcing member may be joined to the bottom plate.

[0012] With this configuration, the bottom plate can also bear the load integrally, thus ensuring even higher battery protection against impacts in the front-to-rear direction of the vehicle.

[0013] The aforementioned automotive battery case may further include a cross member positioned within the under cover and extending from the left end to the right end in the vehicle width direction of the housing portion.

[0014] This configuration allows for a load transmission path in the vehicle width direction using the cross member, ensuring high battery protection performance against impacts in the vehicle width direction.

[0015] The aforementioned automotive battery case may further include a frame that is positioned around the entire outer circumference of the under cover when viewed from the vertical direction of the vehicle.

[0016] This configuration allows the frame to protect the entire perimeter of the underbody, thus ensuring even greater battery protection.

[0017] The material of the under cover may be steel with a tensile strength of 590 MPa or more.

[0018] This configuration allows for even greater battery protection through an underbody cover made of high-strength steel.

[0019] The aforementioned automotive battery case may further include a cooling unit located inside the under cover to cool the battery.

[0020] This configuration allows the battery to be cooled by the cooling unit, thus enabling stable battery operation.

[0021] The cooling unit is A flat mounting plate may be disposed above the lower surface overhang portion within the under cover, defining a bottom space between the mounting plate and the lower surface of the under cover, and a heat radiating portion may be provided which is accommodated in the bottom space and releases heat of the battery conducted through the mounting plate.

[0022] According to this configuration, since the heat radiating portion is accommodated in the bottom space, space can be saved.

[0023] The automotive battery case may further include an upper cover which serves as a lid for closing the under cover from above, and an upper surface overhang portion extending from the left end to the right end in the vehicle width direction and protruding upward is provided on the upper surface.

[0024] According to this configuration, a load transmission path can be provided in the vehicle width direction by the upper surface overhang portion of the upper cover, and high battery protection performance against impacts in the vehicle width direction can be ensured.

Advantages of the Invention

[0025] According to the present invention, in an automotive battery case, high battery protection performance against impacts in the vehicle longitudinal direction can be ensured with a simple structure.

Brief Description of the Drawings

[0026] [Figure 1] Side view of an automobile. [Figure 2] Perspective view of an automotive battery case according to the first embodiment of the present invention. [Figure 3] Exploded perspective view of the automotive battery case of FIG. 2. [Figure 4] Perspective view showing an under cover, a lower surface longitudinal reinforcing member, a cooling portion, and a cross member. [Figure 5] Perspective view showing an under cover and a lower surface longitudinal reinforcing member. [Figure 6] Perspective view of a vehicle body lower structure equipped with the automotive battery case of FIG. 2. [Figure 7]A perspective view of an automobile battery case according to a second embodiment of the present invention. [Figure 8] Figure 7 shows an exploded perspective view of an automobile battery case. [Figure 9] A cross-sectional view showing the first modified example of the cooling section. [Figure 10] A cross-sectional view showing a second modified example of the cooling section. [Figure 11] A cross-sectional view showing a third modified example of the cooling section. [Modes for carrying out the invention]

[0027] Embodiments of the present invention will be described below with reference to the attached drawings.

[0028] (First Embodiment) Referring to Figure 1, vehicle 1 is driven by a motor powered by electricity supplied from battery 10. For example, vehicle 1 may be an electric vehicle or a plug-in hybrid vehicle. The type of vehicle 1 is not particularly limited and may be a passenger car, truck, work vehicle, or other mobility vehicle. In the following, the case of a regular passenger car type electric vehicle will be described as an example of vehicle 1.

[0029] Automobile 1 has a motor and high-voltage equipment mounted in the front part 20 of the vehicle body. Furthermore, Automobile 1 has an automobile battery case 100 (hereinafter simply referred to as battery case 100) housing a battery 10, which serves as the power source for the vehicle, mounted on approximately the entire surface below the passenger compartment R in the central part 30 of the vehicle body. In Figure 1, the longitudinal direction of Automobile 1 is indicated by the X direction (arrows indicate forward), and the vertical direction of the vehicle is indicated by the Z direction (arrows indicate upward). The same notation is used in subsequent figures, and from Figure 2 onwards, the vehicle width direction of Automobile 1 is indicated by the Y direction (arrows indicate right).

[0030] Referring to Figures 2-5, the battery case 100 of this embodiment includes an upper cover 110, a cross member 120, a cooling section 130, an under cover 140, a frame 150, a lower vertical reinforcement member 160, and a bottom plate 170. In Figure 3, the battery 10 housed in the battery case 100 is schematically shown as four rectangular parallelepipeds. The battery 10 has a shape that is elongated in the vehicle width direction and is arranged in a line in the vehicle front-rear direction.

[0031] The under cover 140 is a tray-shaped component formed by press-forming a single metal plate. In other words, the under cover 140 is a press-formed single-piece part that does not have seams such as joints. The under cover 140 has a housing section 141 for housing the battery 10, and the lower surface 142 of the housing section 141 is provided with a lower surface overhang 143 that extends upward from the front end to the rear end in the vehicle's longitudinal direction. The number of lower surface overhangs 143 may be one or more.

[0032] In this embodiment, multiple through-holes 144 are provided in the lower surface 142 of the under cover 140, so that even if coolant leaks from the cooling section 130 (described later) into the housing section 141, it can be discharged downward through the multiple through-holes 144. Furthermore, considering sealing performance, the multiple through-holes 144 may have a sealing structure to prevent water from entering from the road, or they may simply be omitted.

[0033] The under cover 140 is made of, for example, steel. Specifically, the material of the under cover 140 may be steel with a tensile strength of 590 MPa or more. An under cover 140 made of high-strength steel can ensure even higher battery protection performance. Alternatively, the material of the under cover 140 may be other metal materials such as aluminum alloy.

[0034] The cooling unit 130 is located inside the under cover 140 and cools the battery 10. In this embodiment, the cooling unit 130 is formed by bonding two metal plates (for example, aluminum plates) together. In addition, a plurality of brackets 133 are provided to fix the position of the cooling unit 130. The plurality of brackets 133 are arranged along both sides of the housing unit 141 in the vehicle width direction.

[0035] In this embodiment, the cooling unit 130 includes a flat mounting plate 131 and a plate-shaped heat dissipation unit 132 having grooves. The mounting plate 131 is flat and is positioned on a lower overhang 143 via a bracket 133. A bottom space Sb is defined between the mounting plate 131 and the lower surface 142 of the under cover 140. The heat dissipation unit 132 is attached to the lower surface of the mounting plate 131 and positioned in the bottom space Sb. The heat dissipation unit 132 has grooves 132a that serve as passages for low-temperature coolant to dissipate heat from the battery 10 conducted through the mounting plate 131. The grooves 132a are formed in a bellows shape so as to fold back in the front-rear direction of the vehicle in order to secure a heat dissipation area. The passage for the coolant is defined by the grooves 132a being closed from above by the mounting plate 131. The coolant is configured to circulate between the battery case 100 and a cooling device of any configuration.

[0036] The cross members 120 are positioned within the under cover 140 and extend from the left end to the right end in the vehicle width direction of the housing section 141. In this embodiment, three cross members 120 are provided and are arranged to partition multiple cooling sections 130. However, the number of cross members 120 is not particularly limited. The cross members 120 have a cross shape that is roughly hat-shaped in the vehicle width direction and have a relief section 121 that is complementary in shape to the lower protruding section 143 so as not to interfere with the convex section 143a.

[0037] The cross member 120 is made of, for example, steel. Specifically, the material of the cross member 120 may be steel with a tensile strength of 980 to 1470 MPa or higher. Alternatively, the material of the cross member 120 may be other metallic materials such as aluminum alloy. Note that the cross member 120 may be omitted if necessary.

[0038] The upper cover 110 is a lid that closes the under cover 140 from above. The battery 10 is placed on the mounting plate 131 inside the under cover 140 and is stored in the battery case 100 when the upper cover 110 closes it from above.

[0039] In this embodiment, the upper cover 110 has an upper surface projection 112 that extends upward from the left end to the right end in the vehicle width direction on the upper surface 111.

[0040] In this embodiment, four rectangular parallelepiped batteries 10 arranged in the front-to-rear direction of the vehicle are housed in the battery case 100, so four upper protrusions 112 are provided corresponding to the four batteries 10. The number of upper protrusions 112 may be one or more.

[0041] In this embodiment, the upper cover 110 is formed by press-forming a single metal plate, similar to the under cover 140. That is, the upper cover 110 is a press-formed single-piece product that does not have seams such as joints.

[0042] The upper cover 110 is made of, for example, steel. Specifically, the material of the upper cover 110 may be mild steel. Alternatively, the material of the upper cover 110 may be other metallic materials such as aluminum alloy.

[0043] The frame 150 is positioned around the entire outer circumference of the under cover 140 when viewed from the vertical direction of the vehicle. In this embodiment, the frame 150 is rectangular when viewed from the vertical direction of the vehicle. The frame 150 includes a front frame 151 positioned at the front, a rear frame 152 positioned at the rear, and side frames 153 and 154 positioned on both sides. The front frame 151 and the rear frame 152 extend in the vehicle width direction, while the side frames 153 and 154 extend in the vehicle longitudinal direction. The front frame 151, the rear frame 152, and the side frames 153 and 154 are joined together by welding or the like.

[0044] The front frame 151, rear frame 152, and side frames 153, 154 are formed, for example, by roll-forming steel plates into a tubular shape. Specifically, these materials may be steel with a tensile strength of 980 to 1470 MPa or higher. Alternatively, these materials may be other metallic materials such as aluminum alloys. Frame 150 may be omitted if necessary.

[0045] The lower longitudinal reinforcing members 160 have a roughly hat shape in a cross section perpendicular to the vehicle's longitudinal direction and are members that reinforce the under cover 140. The lower longitudinal reinforcing members 160 extend in the vehicle's longitudinal direction from the front end to the rear end of the under cover 140 along the lower overhang 143 below the under cover 140 (outside the under cover 140), and are positioned to be at least partially housed within the lower overhang 143. In the illustrated example, three lower longitudinal reinforcing members 160 are provided corresponding to three lower overhangs 143. The lower longitudinal reinforcing members 160 have a shape complementary to the lower overhangs 143. The lower longitudinal reinforcing members 160 are joined to the under cover 140 via spacers 161. The spacers 161 provide a gap between the lower longitudinal reinforcing members 160 and the under cover 140.

[0046] The lower vertical reinforcing member 160 is made of, for example, steel. Specifically, the material of the lower vertical reinforcing member 160 may be steel with a tensile strength of 980 to 1470 MPa or higher. Alternatively, the material of the lower vertical reinforcing member 160 may be other metallic materials such as aluminum alloy.

[0047] The bottom plate 170 is a metal plate positioned below the under cover 140 and the lower vertical reinforcing member 160. The bottom plate 170 is a rectangle approximately the same size as the frame 150 when viewed from the top and bottom of the vehicle. The lower vertical reinforcing member 160 is joined to the bottom plate 170. The bottom plate 170 is provided with multiple through holes 171 so that if coolant from the cooling unit 130 leaks out, it can be discharged downward through the multiple through holes 171. However, the multiple through holes 171 may be omitted.

[0048] In this embodiment, the bottom plate 170 is flat. The bottom plate 170 is, for example, a steel plate with a thickness of 1.4 mm. However, the thickness and material of the bottom plate 170 are not particularly limited and can be any. The bottom plate 170 may be omitted if necessary.

[0049] Referring to Figure 6, the battery case 100 having the above configuration constitutes a part of the underbody structure of the automobile 1, as will be described below.

[0050] Side sills 200 are positioned on both outer sides of the battery case 100 in the vehicle width direction. The side sills 200 extend in the vehicle's longitudinal direction and are components that constitute the outer surface of the automobile 1 in the vehicle width direction. The side sills 200 are constructed by bonding together an inner panel 210 and an outer panel 220, which are metal plates, and by positioning a cushioning member 230 in the space between the inner panel 210 and the outer panel 220. The cushioning member 230 has a plurality of chambers r1 arranged in the vehicle width direction and has the function of cushioning impacts from the side of the automobile 1.

[0051] A floor panel 300, which constitutes the floor surface of the passenger compartment R, is positioned between the side sills 200 in the vehicle width direction and above the battery case 100 in the vehicle height direction. The floor panel 300 is a flat metal plate. Multiple (three in the illustrated example) floor crosses 310 are positioned on top of the floor panel 300. The multiple floor crosses 310 extend in the vehicle width direction to connect a pair of side sills 200.

[0052] The automotive battery case 100 of this embodiment provides the following effects and advantages.

[0053] The underbody cover 140's underbody overhang 143 provides a load transmission path in the longitudinal direction of the vehicle, ensuring high battery protection against impacts in the longitudinal direction with a simple structure. Specifically, by providing the underbody overhang 143, the load-bearing capacity can be improved compared to a simple flat plate, allowing for the transmission of greater loads. Furthermore, since the underbody vertical reinforcing member 160 is at least partially housed in the underbody overhang 143, space can be utilized efficiently. In addition, since the underbody cover 140 is a press-formed product made by press-forming a single metal plate, it does not have seams like joints, thus preventing water from entering from the road surface and ensuring high sealing performance.

[0054] Furthermore, since the under cover 140 and the lower vertical reinforcement member 160 are joined to each other, the under cover 140 and the lower vertical reinforcement member 160 can bear the load as a single unit. Therefore, even higher battery protection performance against impacts in the front-to-rear direction of the vehicle can be ensured.

[0055] Furthermore, since the bottom plate 170 and the lower vertical reinforcing member 160 are joined to each other, the bottom plate 170 can also bear the load. Therefore, even higher battery protection performance against impacts in the front-to-rear direction of the vehicle can be ensured.

[0056] Furthermore, the cross member 120 allows for a load transmission path in the vehicle width direction, ensuring high battery protection performance against impacts in the vehicle width direction.

[0057] Furthermore, the frame 150 protects the entire circumference of the under cover 140, thus ensuring even higher battery protection.

[0058] Furthermore, the cooling unit 130 can cool the battery 10, enabling stable operation of the battery 10. In addition, since the heat dissipation unit 132 is housed in the bottom space Sb, space can be saved.

[0059] Furthermore, the upper protrusion 112 of the upper cover 110 provides a load transmission path in the vehicle width direction, ensuring high battery protection performance against impacts in the vehicle width direction.

[0060] (Second Embodiment) The automotive battery case 100 of the second embodiment shown in Figures 7 and 8 does not have a cross member 120, and the battery 10, cooling unit 130, and upper cover 110 differ from those of the first embodiment. Aside from these parts, it is substantially the same as the first embodiment. Therefore, explanations of parts shown in the first embodiment may be omitted.

[0061] In this embodiment, two rectangular parallelepiped batteries 10, which are long in the front-to-rear direction of the vehicle, are housed in a battery case 100, arranged in the vehicle width direction.

[0062] The cooling section 130 is arranged in close proximity to the battery 10 in the vehicle width direction. The flow path formed by the groove 132a extends along the entire length in the vehicle's longitudinal direction and is folded back in the vehicle's longitudinal direction to form a bellows-like structure.

[0063] The upper cover 110 is tray-shaped and functions as a lid. The upper surface of the upper cover 110 is flat, and there is no upper protrusion 112 (see Figure 2) as in the first embodiment.

[0064] The under cover 140 does not have multiple through holes 144 (see Figure 3) as in the first embodiment. Similarly, the bottom plate 170 does not have multiple through holes 171 (see Figure 3) as in the first embodiment.

[0065] The effects and advantages of the automotive battery case 100 of this embodiment are substantially the same as those of the first embodiment, except for those relating to configurations that differ from the first embodiment. However, in this embodiment, the number of parts is reduced compared to the first embodiment, and the structure of each part, such as the upper cover 110 or the cooling section 130, is simplified.

[0066] Although specific embodiments and variations of the present invention have been described above, the present invention is not limited to the above embodiments and can be implemented with various modifications within the scope of this invention. For example, each component of the first embodiment and each component of the second embodiment can be suitably substituted for each other.

[0067] Furthermore, the configuration of the cooling unit 130 can vary, as shown in Figures 9 to 11. Figures 9 to 11 show cross-sections along line AA in Figure 4. Figures 9 to 11 show the upper cover 110 and frame 150 removed.

[0068] Referring to Figure 9, the heat dissipation section 132 of the cooling section 130 may be a heat sink. The heat dissipation section 132 is housed in the bottom space Sb and absorbs heat from the mounting plate 131, which has become hot due to the conduction of heat from the battery 10, and dissipates heat into the air.

[0069] Referring to Figure 10, the heat dissipation section 132 of the cooling section 130 may be positioned along the side of the battery 10. In the illustrated example, the heat dissipation section 132 is positioned adjacent to the outer surface of the battery 10 in the vehicle width direction. However, the heat dissipation section 132 may also be positioned adjacent to the outer surface of the battery 10 in the vehicle longitudinal direction. The heat dissipation section 132 is formed by roll-forming a single metal plate (e.g., an aluminum plate) and is constructed in a tubular shape having multiple chambers r2. The multiple chambers r2 serve as passages through which the cooling fluid flows.

[0070] Alternatively, referring to Figure 11, the heat dissipation section 132 may be constructed by sandwiching a single metal plate (e.g., an aluminum plate) that has been bent into a corrugated shape between two opposing metal plates (e.g., aluminum plates). In this case as well, as in Figure 10, multiple chambers r3 are formed, and these multiple chambers r3 serve as channels through which the cooling liquid flows. In the examples of Figures 10 and 11, nothing is placed in the bottom space Sb, but another heat dissipation section 132, such as the aforementioned heat sink, may be placed there. [Explanation of Symbols]

[0071] 1. Automobile 10 batteries 20 Front of the vehicle 30 Center of the vehicle 100 Battery Cases (Automotive Battery Cases) 110 Upper Cover 111 Top surface 112 Top protrusion 120 Crossmember 121 Escape Club 130 Cooling section 131 Mounting plate 132 Heat radiation part 132a Groove 133 Bracket 140 Undercover 141 Storage Unit 142 Bottom surface 143 Lower surface overhang 144 Through holes 150 frames 151 Front Frame 152 Rear Frame 153,154 Side Frame 160 Bottom vertical reinforcement 161 Spacer 170 Bottom Plate 171 Through hole 200 Side Sill 210 Inner Panel 220 Outer Panel 230 Cushioning material 300 Floor Panels 310 Floorcloth

Claims

1. An under cover is a tray-shaped press-formed product having a storage compartment for housing a battery, and the underside of the storage compartment has a lower protrusion that extends upward in the vehicle's longitudinal direction from the front end to the rear end. A lower longitudinal reinforcing member is positioned below the under cover, along the lower protrusion, extending in the vehicle longitudinal direction from the front end to the rear end of the under cover, and arranged so as to be at least partially housed in the lower protrusion. A car battery case equipped with [feature / feature].

2. The automobile battery case according to claim 1, wherein the under cover and the lower vertical reinforcing member are joined to each other.

3. The system further comprises a flat bottom plate positioned below the under cover and the lower vertical reinforcing member, The lower vertical reinforcing member is joined to the bottom plate, as described in claim 1 or 2, for an automobile battery case.

4. The automobile battery case according to claim 1 or 2, further comprising a cross member disposed within the under cover and extending from the left end to the right end in the vehicle width direction of the housing portion.

5. The automotive battery case according to claim 1 or 2, further comprising a frame arranged around the entire outer circumference of the under cover when viewed from the vertical direction of the vehicle.

6. The automobile battery case according to claim 1 or 2, wherein the material of the under cover is steel with a tensile strength of 590 MPa or more.

7. The automotive battery case according to claim 1 or 2, further comprising a cooling unit disposed within the under cover for cooling the battery.

8. The cooling unit is A flat mounting plate is positioned within the under cover on the lower protruding portion and defines a bottom space between it and the lower surface of the under cover, A heat dissipation section is housed in the bottom space and releases heat from the battery that has been conducted through the aforementioned mounting plate. The automotive battery case according to claim 7, comprising:

9. The automobile battery case according to claim 1 or 2, further comprising an upper cover which serves as a lid to close the under cover from above, and which has an upper surface projection that extends from the left end to the right end in the vehicle width direction and protrudes upward on its upper surface.

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