Battery box for electric vehicle

Abstract

The battery box (100) for an electric vehicle comprises: a bathtub-shaped tray (120) having a concave receiving portion (122) for receiving a battery (30); a frame (110) arranged to surround the entire circumference of the tray (120) in a plan view and connected to the tray (120); a top cover (130) arranged above the tray (120) and closing the receiving portion (122); and a bottom cover (140) arranged below the tray (120).

Description

Technical Field

[0001] The present invention relates to a battery box for an electric vehicle. Background Art

[0002] Electric vehicles such as electric cars need to be equipped with large-capacity batteries to ensure sufficient cruising range, and on the other hand, they require a large cabin. In order to meet these requirements at the same time, in most electric cars, large-capacity batteries are stored in battery boxes and mounted on the entire surface under the floor of the vehicle. Therefore, for battery boxes for electric vehicles, high sealing properties are required to prevent water from entering from the road surface and other factors and prevent poor electronic components, and high impact strength is required to protect the internal batteries.

[0003] For example, Patent Document 1 discloses a battery box that improves sealing by using a tray formed into a bathtub shape by cold rolling and stamping a metal plate. In addition, Patent Document 2 discloses a battery box that improves space efficiency and impact strength by joining a bottom plate and a frame of the battery box by welding or other joining means.

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2017-226353

[0006] Patent Document 2: Japanese Patent Application Publication No. 2012-212659.

[0007] In the battery box of Patent Document 1, the frame does not surround the entire periphery of the battery box, so there is room for improvement in terms of impact strength. In addition, the bathtub-shaped tray constitutes the lower surface of the vehicle body, so there is room for improvement in terms of strength against lifting from the road surface.

[0008] In the battery box of Patent Document 2, since a bathtub-shaped tray is not used, it is necessary to prevent water from entering from welded joints and the like, and there is room for improvement in terms of sealing properties. Summary of the invention

[0009] An object of the present invention is to ensure sufficient sealing performance and strength in a battery box for an electric vehicle.

[0010] The present invention provides a battery box for electric vehicles, comprising: a bathtub-shaped tray having a concave receiving portion for receiving batteries, a frame connected to the tray and arranged in a manner to surround the entire circumference of the tray in a plan view, a top cover arranged above the tray and closing the receiving portion, and a bottom cover arranged below the tray.

[0011] According to this structure, the receiving portion is sealed by the tray and the top cover. In particular, the tray is in the shape of a bathtub, so no seam is provided except for the joint between the tray and the top cover. Therefore, high sealing can be ensured for the battery receiving portion without the need for full-circumferential welding or the like. In addition, the frame is configured to surround the entire circumference of the tray, so high impact strength can be ensured. In addition, since the bottom cover is arranged below the tray, the tray is not exposed on the lower surface of the vehicle body, and high strength against the top from the road surface can be ensured.

[0012] The bottom cover may be made of a material different from that of the frame, and may be joined to the frame by a different material.

[0013] According to this structure, the material of the bottom cover and the frame can be changed according to the purpose to improve the versatility of the battery box for electric vehicles. For example, the frame can be made of aluminum alloy to reduce weight, and the bottom cover can be made of steel to improve the strength of the top from the road surface. Here, dissimilar material joining refers to the joining method of different metal materials, such as bolt joining, riveting joining, or EASW (Element Arc Spot Welding).

[0014] The aforementioned tray may be made of plastic.

[0015] According to this structure, the shape of the tray can be arbitrarily formed and the tray can be made lightweight. In particular, it is preferred that the storage portion of the tray has a larger capacity and a smaller rounded corner of the ridge portion in order to accommodate batteries with as large a capacity as possible. In contrast, by making the tray made of plastic, it can be easily formed.

[0016] The frame includes an upper cross beam extending in a vehicle width direction and a lower cross beam disposed below the upper cross beam in the vehicle width direction, and the tray is sandwiched between the upper cross beam and the lower cross beam in a vehicle height direction.

[0017] According to this structure, the upper cross beam and the lower cross beam can be used to improve the strength of the vehicle body against side impact. In addition, the pallet is clamped by the upper cross beam and the lower cross beam, so that the pallet can be stably fixed. In addition, the upper cross beam and the lower cross beam can be formed of different materials, so it is easy to achieve lightweight and high impact strength from the side of the vehicle body according to the required performance.

[0018] The top cover, the upper cross beam, the tray, and the lower cross beam may also have concentric holes in a plan view, bolts are inserted through the concentric holes, the bolts completely penetrate the top cover, the upper cross beam, and the tray and do not completely penetrate the lower cross beam, and the bolts remain in the vehicle body, so that the top cover, the upper cross beam, the tray, and the lower cross beam are integrally combined with the vehicle body.

[0019] According to this structure, the top cover, the upper cross member, the tray, and the lower cross member are firmly connected to the vehicle body via bolts. In the battery box, such a structure that is firmly fixed to the vehicle body in a manner that does not excessively vibrate the battery is effective. In addition, since the bolts do not completely penetrate the lower cross member, it is possible to prevent the sealing from being damaged.

[0020] The vehicle may further include a corrugated panel disposed between the tray and the undercover in the vehicle height direction.

[0021] According to this structure, the corrugated panel can further improve the roof strength. In particular, the corrugated panel absorbs shocks appropriately, so it is effective for improving the roof strength.

[0022] According to the present invention, sufficient sealing performance and strength can be ensured in the battery box for an electric vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a side view of an electric vehicle equipped with the electric vehicle battery pack according to one embodiment of the present invention.

[0024] Figure 2 This is a schematic cross-sectional view of the vicinity of the case member of the battery box.

[0025] Figure 3 This is an exploded perspective view of the battery box.

[0026] Figure 4 It is a three-dimensional diagram of the battery box.

[0027] Figure 5 This is a schematic cross-sectional view of the vicinity of the crossbeam of the battery box.

[0028] Figure 6 It is a schematic cross-sectional view of the vicinity of a beam of a battery box in a modified example.

[0029] Description of Reference Numerals

[0030] 1 Electric Vehicles

[0031] 10 Front of the vehicle

[0032] 20 Center of the vehicle body

[0033] 30 Battery

[0034] 31Electrical cables

[0035] 100 battery box (battery box for electric vehicles)

[0036] 110 Frame

[0037] 111 frame body

[0038] 111a Anterior wall

[0039] 111b Back wall

[0040] 111c, 111d side wall

[0041] 112 beam

[0042] 112a Upper crossbeam

[0043] 112b Lower side beam

[0044] 112b1 partition wall

[0045] 112b2 flange

[0046] 113 medial extension

[0047] 113a hole

[0048] 120 pallets

[0049] 121 flange

[0050] 122 Containment Sector

[0051] 122a bottom

[0052] 122b extension

[0053] 123 threaded parts

[0054] 124 bolts

[0055] 130 top cover

[0056] 140 bottom cover

[0057] 141, 142 components

[0058] 150 corrugated panel

[0059] 200 cabinet parts

[0060] 300 Ground Panel

[0061] 400 ground beams. DETAILED DESCRIPTION

[0062] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0063] Reference Figure 1The electric vehicle 1 is a vehicle that is driven by a motor using power supplied from a battery 30. The electric vehicle 1 may be a vehicle that is driven by power, such as an electric vehicle or a hybrid vehicle. The type of vehicle is not particularly limited, and may be a passenger car, a truck, a work vehicle, or other mobile equipment. Hereinafter, a case where a passenger car type electric vehicle is used as an example of the electric vehicle 1 will be described.

[0064] The electric vehicle 1 is equipped with a motor, high voltage equipment, etc. (not shown) at the front portion 10 of the vehicle body. In addition, the electric vehicle 1 is equipped with an electric vehicle battery box 100 (hereinafter referred to as the battery box 100 ) for storing the battery 30 on substantially the entire surface under the floor of the vehicle compartment R at the center portion 20 of the vehicle body. Figure 1 In the figure, the X direction represents the front-rear direction of the electric vehicle 1, and the Z direction represents the height direction (up-down direction). The same is also used in the following figures. Figure 2 Hereinafter, the Y direction will be used to represent the vehicle width direction.

[0065] Reference Figure 2 The battery box 100 is arranged inside the box member 200 in the vehicle width direction and is supported by the box member 200. The box member 200 is an electric vehicle 1 ( Figure 1 The box member 200 is formed by joining a plurality of metal plates and has the function of protecting the vehicle cabin R and the battery box 100 from a collision from the side of the electric vehicle 1.

[0066] Also refer to Figure 3 , 4 The battery box 100 includes a frame 110 defining a through hole TH, a bathtub-shaped tray 120, a top cover 130 and a bottom cover 140 arranged to sandwich them from above and below. In addition, in the present embodiment, the battery box 100 preferably further includes a plurality of corrugated panels 150 arranged between the tray 120 and the bottom cover 140 in the vehicle height direction.

[0067] The frame 110 is a frame-shaped component that is the skeleton of the battery box 100. In this embodiment, it is made of, for example, an aluminum alloy extrusion product. The frame 110 can be made of an aluminum alloy extrusion product, an aluminum alloy casting product, a magnesium alloy extrusion product, a magnesium alloy casting product, or a combination thereof. The frame 110 includes a frame body 111 that is rectangular in a plan view, and four cross beams 112 that extend in the vehicle width direction in the frame body 111.

[0068] The cross member 112 includes four upper cross members 112a extending in the vehicle width direction and four lower cross members 112b arranged below the upper cross members 112a in the vehicle width direction. The four upper cross members 112a are connected by electric cables 31. The electric cables 31 are connected to the battery 30.

[0069] In this embodiment, the frame 110 having the through hole TH is described as an example, but the shape of the frame 110 is not particularly limited. For example, the frame 110 may include a hollow portion having a concave shape instead of the through hole TH.

[0070] The frame body 111 includes: side walls 111c and 111d extending in the front-rear direction of the vehicle, and a front wall 111a and a rear wall 111b connecting the side walls 111c and 111d and extending in the vehicle width direction. The side walls 111c and 111d are substantially L-shaped in a cross section perpendicular to the front-rear direction of the vehicle. The inside of the side walls 111c and 111d is divided into a plurality of compartments and is hollow. The front wall 111a and the rear wall 111b are in a four-sided cylindrical shape, and the inside of the front wall 111a and the rear wall 111b is also hollow.

[0071] The four upper horizontal beams 112 a and the four lower horizontal beams 112 b extend in parallel with the front wall 111 a and the rear wall 111 b , and are arranged at substantially equal intervals.

[0072] Also refer to Figure 3 , 5 The upper cross beam 112a is disposed in the tray 120, and contacts the inner surface of the tray 120 at both ends in the vehicle width direction. The upper cross beam 112a is hollow, and specifically has a rectangular closed cross-sectional shape in a cross section perpendicular to the vehicle width direction. For example, the upper cross beam 112a is made of high-tensile steel.

[0073] The lower cross beam 112b is arranged below the upper cross beam 112a, and connects the side wall 111c and the side wall 111d. The lower cross beam 112b is hollow, and more specifically, has a rectangular closed cross-sectional shape in a cross section perpendicular to the vehicle width direction, the interior of which is partitioned by a partition wall 112b1. In addition, the lower cross beam 112b has a flange portion 112b2 at the lower end for joining with the bottom cover 140. The flange portion 112b2 extends in a horizontal plane parallel to the bottom cover 140. The lower cross beam 112b is, for example, an extruded product made of an aluminum alloy (aluminum alloy extrusion).

[0074] The cross beam 112 (upper cross beam 112a, lower cross beam 112b) has a function of increasing the strength of the battery box 100. In particular, the cross beam 112 can increase the strength of the electric vehicle 1 ( Figure 1However, the crossbeam 112 is not a necessary structure and can be omitted as needed. In addition, even when the crossbeam 112 is provided, its form is not particularly limited, and the shape, configuration, and number of crossbeams can be arbitrarily set.

[0075] Reference Figure 3 The tray 120 is a bathtub-shaped member for storing the battery 30, and is made of plastic, for example. The tray 120 has a flange portion 121 extending in the horizontal direction (X and Y directions) at the outer edge, and a receiving portion 122 that is continuous with the flange portion 121 and has a concave shape. The receiving portion 122 is a portion for storing the battery 30. A protruding portion 122b having a complementary shape to the lower side beam 112b is provided on the bottom 122a of the receiving portion 122.

[0076] Reference Figure 5 , a lower cross beam 112b is arranged below the extension 122b, and an upper cross beam 112a is arranged above the extension 122b. That is, the tray 120 is clamped by the upper cross beam 112a and the lower cross beam 112b in the vehicle height direction. In this embodiment, the upper cross beam 112a, the extension 122b, and the lower cross beam 112b are fastened together using screws 123. In addition, although not shown in detail, the upper cross beam 112a and the top cover 130 are also screwed.

[0077] Also refer to Figure 3 , 4 In the state where the tray 120 and the frame 110 are combined, the flange portion 121 of the tray 120 is placed on the upper surface of the frame body 111 of the frame 110, and the receiving portion 122 of the tray 120 is arranged in the frame body 111 of the frame 110. At this time, the extension portion 122b is arranged to partially cover the lower side beam 112b.

[0078] Also refer to Figure 2 , 3 , batteries 30 (5 in this embodiment) are arranged in the receiving portion 122 of the tray 120. The receiving portion 122 is closed by the top cover 130 from above the battery 30, so that the battery 30 is accommodated in the battery box 100. In the illustrated example, the top cover 130 and the tray 120 are fastened and fixed to the frame 110 by screws. A floor panel 300 constituting the floor of the vehicle room R and a floor cross beam 400 extending in the vehicle width direction in the vehicle room R are arranged above the top cover 130. In addition, a bottom cover 140 is arranged below the tray 120. The bottom cover 140 is joined to the frame 110 to constitute the lower surface of the vehicle body.

[0079] Preferably, the bottom cover 140 is made of a material different from that of the frame 110. Thus, the materials of the bottom cover 140 and the frame 110 can be changed according to the application, and the versatility of the battery box 100 can be improved. In this embodiment, the frame 110 is made of, for example, aluminum alloy as described above, while the bottom cover 140 is made of, for example, steel. Therefore, the frame 110 can be made lighter and the strength of the bottom cover 140 against the top from the road surface can be improved.

[0080] Reference by Figure 2 In the partial enlarged view shown by the dotted circle, the bottom cover 140 is joined with dissimilar materials relative to the frame 110. Dissimilar material joining refers to the joining method of dissimilar metal materials to each other, such as bolt joining, riveting joining, or EASW (Element Arc Spot Welding). In this embodiment, EASW (Element Arc Spot Welding) is adopted as the dissimilar material joining. In EASW, a steel rivet (element) 141 with a hollow flange is embedded in the hole 113a of the inner extension 113 of the frame 110 made of aluminum alloy, placed on the bottom cover 140 made of steel, and welding material melted by arc welding is cast into the hollow part in the element 141. That is, by arc welding from one side, the element 141 and the bottom cover 140 are firmly welded. At this time, the frame 110 is clamped between the flange of the element 141 and the bottom cover 140 and joined to them. In order to improve the sealing performance of the inner side (upper side) of the bottom cover 140 , a known adhesive or sealant may be used in the joint portion.

[0081] Reference Figure 5 In this embodiment, the lower cross member 112b is also joined to the bottom cover 140 by different materials. Specifically, the flange portion 112b2 of the lower cross member 112b is joined to the bottom cover 140 by using the element 142 using EASW as described above. In this joint portion, in order to improve the sealing performance of the inner side (upper side) of the bottom cover 140, a known adhesive or sealant may be used.

[0082] In addition, in the present embodiment, a corrugated panel 150 is disposed between the tray 120 and the bottom cover 140 in the vehicle height direction. A plurality of corrugated panels 150 (five in the present embodiment) are provided corresponding to the number of batteries 30 (five in the present embodiment). The corrugated panel 150 has a corrugated cross section when viewed in the vehicle width direction. The corrugated panel 150 has a function of alleviating the upward impact from the road surface.

[0083] According to the battery pack 100 as described above, the following effects are achieved.

[0084] According to the present embodiment, the receiving portion 122 is sealed by the tray 120 and the top cover 130. In particular, since the tray 120 is in the shape of a bathtub, no seam is provided except for the joint between the tray 120 and the top cover 130. Therefore, high sealing can be ensured with respect to the receiving portion 122 of the battery 30 without the need for full-circle welding or the like. In addition, the frame 110 is arranged in a manner surrounding the entire circumference of the tray 120, so that high impact strength can be ensured. In addition, the bottom cover 140 is arranged below the tray 120, so that the tray 120 is not exposed on the lower surface of the vehicle body, and high strength against the top from the road surface can be ensured.

[0085] Furthermore, since the tray 120 is made of plastic, the shape of the tray 120 can be arbitrarily formed, and the tray 120 can be made lightweight. In particular, the storage portion 122 of the tray 120 is preferably increased in capacity and the rounded corners of the ridge portion are reduced in order to store the battery 30 with the largest possible capacity. In contrast, by making the tray 120 made of plastic, such forming can be easily performed.

[0086] In addition, the upper cross beam 112a and the lower cross beam 112b are provided, so that the strength of the vehicle body against side impact can be improved compared to a vehicle body without these. In addition, the pallet 120 is clamped by the upper cross beam 112a and the lower cross beam 112b, so the pallet can be stably fixed. In addition, the upper cross beam 112a and the lower cross beam 112b can be formed of different materials, so that it is easy to achieve lightweight and high impact strength from the side according to the necessary performance. For example, as in the present embodiment, the upper cross beam 112a can be made of high-tensile steel to ensure high impact strength from the side of the vehicle body, and the lower cross beam 112b can be made of aluminum alloy to achieve lightweight.

[0087] Furthermore, the strength of the vehicle body from the road surface can be further improved by providing the corrugated panel 150. In particular, the corrugated panel 150 is effective in improving the strength of the vehicle body from the road surface because it absorbs shock appropriately.

[0088] (Variation)

[0089] Reference Figure 6 Modifications of this embodiment will be described.

[0090] In the modified example, the screw member 123 ( Figure 5), the top cover 130, the upper cross beam 112a, the tray 120, and the lower cross beam 112b are fixed integrally with the bolt 124. In order to insert the bolt 124 in the up-down direction, the top cover 130, the upper cross beam 112a, the tray 120, and the lower cross beam 112b have concentric holes CH in a plan view. The concentric holes CH are provided so that the bolt 124 completely penetrates the top cover 130, the upper cross beam 112a, and the tray 120. In such a manner that the lower cross beam 112b is not completely penetrated by the bolt 124 but the bolt 124 only penetrates the upper surface of the lower cross beam 112b, the hole CH is provided only on the upper surface of the lower cross beam 112b.

[0091] In addition, the bolt 124 is fixed to the vehicle body such as the floor panel 300 at the upper end. Therefore, in the present embodiment, the floor panel 300 is also provided with a concentric hole CH. The bolt 124 is inserted through the concentric hole CH from above, and the floor panel 300, the top cover 130, the upper side cross beam 112a, the tray 120, and the lower side cross beam 112b are fixed integrally from the top in sequence, and fixed at the lower end with a nut. In addition, the bottom cover 140 is joined by different materials using the lower side cross beam 112b and EASW as described above.

[0092] According to this modification, the top cover 130, the upper cross member 112a, the tray 120, the lower cross member 112b, and the bottom cover 140 are firmly connected to the vehicle body such as the floor panel 300 via the bolts 124. In the battery box 100, such a structure that is firmly connected to the vehicle body in a manner that does not excessively apply vibration to the battery 30 is effective.

[0093] If the bolts are arranged in a manner that completely penetrates from the upper surface of the top cover 130 to the lower surface of the bottom cover 140 in the structure of this modification, the necessary sealing may not be ensured. In this modification, the bolts 124 do not completely penetrate the lower cross beam 112b, but only penetrate the upper surface of the lower cross beam 112b, so the bolts 124 do not penetrate the bottom cover 140, and the necessary sealing is ensured on the inner side (upper side) of the bottom cover 140. In addition, in order to further improve the sealing, a known adhesive or a sealant may be used at the contact portion between the bottom cover 140 and the frame 110.

[0094] Although specific embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be implemented with various modifications within the scope of the present invention.

[0095] For example, in the above embodiment, the tray 120 is described as being made of plastic, but the material of the tray 120 is not limited to plastic. The material of the tray 120 may be a metal such as steel or aluminum alloy.

Claims

1. A battery box for an electric vehicle, comprising: A bathtub-shaped tray having a concave receiving portion for receiving batteries, a frame connected to the tray and arranged so as to surround the entire circumference of the tray in a plan view; a top cover disposed above the tray and closing the receiving portion; A bottom cover is arranged below the aforementioned tray, The bottom cover is made of a material different from that of the frame and is joined to the frame by different materials. The frame includes an upper cross member extending in the vehicle width direction and a lower cross member arranged below the upper cross member in the vehicle width direction. The pallet is clamped by the upper cross beam and the lower cross beam in the vehicle height direction. The top cover, the upper beam, the tray, and the lower beam have concentric holes in a plan view. A bolt is inserted through the concentric hole. The bolts completely penetrate the top cover, the upper cross beam, and the tray and do not completely penetrate the lower cross beam. The bolts are retained in the vehicle body, so that the top cover, the upper cross member, the tray, and the lower cross member are integrally connected to the vehicle body.

2. The battery box for electric vehicles according to claim 1, characterized in that: The aforementioned tray is made of plastic.

3. The battery box for electric vehicles according to claim 1 or 2, characterized in that: The vehicle further includes a corrugated panel disposed between the tray and the undercover in the vehicle height direction.

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