Battery case and battery case maintenance method

Abstract

To provide a battery case and a maintenance method for a battery case, capable of reducing cost.SOLUTION: A battery case 10 accommodates a battery 20 at an inside thereof while a lower case 30 and an upper case 40 are assembled. The battery case 10 includes a flange part 12 formed on an outer peripheral surface thereof. The flange part 12 includes: a lower-side flange part 33 overhanging from an upper edge opening in the lower case 30; and an upper-side flange part 43 disposed above the lower-side flange part 33 in the upper case 40. Only an area outside a center C of the flange part 12 in an overhanging direction D is seam welded in a flat plane portion 14 where the lower-side flange part 33 and the upper-side flange part 43 overlap each other in the flange part 12.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a battery case and a maintenance method for a battery case.

Background Art

[0002] The battery case disclosed in Patent Document 1 includes a box-shaped case body having an open upper portion, and a lid covering the opening of the case body. Flange portions are provided on peripheral portions of the case body and the lid. The two flange portions are integrated by interposing a gasket between the two flange portions and fastening fastening members (bolts and nuts).

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] In a state where a battery is accommodated in the battery case of Patent Document 1, it is conceivable that maintenance such as replacement of internal components of the battery case is performed. In this case, it is necessary to cut a portion of the flange portion on the inner side of the fastening member to open the battery case. However, since the cut battery case cannot be reused, it is necessary to prepare a new battery case, which increases the cost.

[0005] The present invention has been completed based on the above circumstances, and an object of the present invention is to provide a battery case capable of reducing costs and a maintenance method for the battery case.

Means for Solving the Problem

[0006] The battery case of the present invention is A battery case comprising a lower case and an upper case, wherein a battery is housed inside when the lower case and the upper case are assembled, and a flange portion is formed on the outer surface, The flange portion is In the lower case, the lower flange portion protruding from the upper edge opening, The upper case has an upper flange portion positioned above the lower flange portion, In the flat planar portion of the flange where the lower flange portion and the upper flange portion overlap, only the area outside the center in the protruding direction of the flange portion is seam-welded.

[0007] The battery case maintenance method of the present invention is: The outer region that is seam-welded in the aforementioned planar portion is separated, The area inward from the center in the direction of protrusion in the planar portion is seam-welded. [Effects of the Invention]

[0008] According to the present invention, it is possible to realize a battery case and a battery case maintenance method that can reduce costs. [Brief explanation of the drawing]

[0009] [Figure 1] This is a side cross-sectional view illustrating the battery case of Example 1. [Figure 2] This is a plan view illustrating the battery case of Example 1. [Figure 3] This is a side view illustrating a vehicle to which the battery case of Embodiment 1 is installed. [Figure 4] This is an enlarged view showing the flange portion in Figure 1. [Figure 5] This is a side cross-sectional view illustrating the process of seam welding the outer welding area. [Figure 6]This is a side view illustrating the process of seam welding the outer welding area. [Figure 7] This is a side cross-sectional view illustrating the process of separating the outer welding area. [Figure 8] This is a side cross-sectional view illustrating the process of seam welding the internally weldable area. [Figure 9] This is a side cross-sectional view illustrating the state in which the internally weldable area has been seam-welded. [Figure 10] This is a side view illustrating the process of bending the tip of the flange. [Figure 11] This is a side view illustrating the state in which the tip of the flange is bent. [Figure 12] This is a side view illustrating a battery case of another embodiment. [Modes for carrying out the invention]

[0010] According to the battery case and battery case maintenance method of the present invention, in the flat planar portion where the lower flange portion and the upper flange portion overlap, only the area outside the center in the protruding direction of the flange portion is seam-welded. Therefore, even if the seam-welded portion is separated due to maintenance or other reasons, it becomes easier to re-weld the area inside the center in the protruding direction of the planar portion. As a result, the battery case can be reused, and costs can be reduced.

[0011] In the battery case of the present invention, it is preferable that in the region of the planar portion inward from the center in the direction of protrusion, a part of the lower flange portion and a part of the upper flange portion are arranged parallel to each other and are seam-weldable. Since a portion of the lower flange and a portion of the upper flange are arranged parallel to each other, they can be reliably welded by seam welding.

[0012] In the battery case of the present invention, it is preferable that a mark is provided on the flat portion at a position near the center in the protruding direction. When attempting to cut off a seam-welded portion for maintenance or the like, the cutting position can be identified by the mark. Therefore, the flange portion can be cut with reference to the mark.

[0013] In the battery case of the present invention, it is preferable that the mark is located outside the center in the protruding direction on the flat portion. The cutting position of the flange portion can be set outside the center in the protruding direction based on the position of the mark. Therefore, the seam-welded portion in the inner region can be easily separated from the cutting position, enabling favorable welding.

[0014] In the battery case of the present invention, it is preferable that the mark consists of a continuous line extending over the entire circumference of the flat portion. Cutting the flange portion along the mark line enables favorable uninterrupted cutting.

[0015] In the battery case of the present invention, it is preferable that the flange portion is made of a metal containing zinc. Since seam welding, which is a type of resistance welding, is used, compared to laser welding, welding can be performed without forming holes even if the flange portion contains zinc.

[0016] In the battery case of the present invention, it is preferable that the outer region of the flange portion is bent upward or downward. The size of the battery case can be reduced.

[0017] In the battery case of the present invention, it is preferable that the joint surface between the lower flange portion and the upper flange portion includes a curved surface. Because the flange portions are joined by seam welding, which involves pressure welding, a good joint can be achieved even if the joint surface is curved. This, in turn, increases the degree of freedom in the shape of the lower and upper flange portions.

[0018] <Example 1> Hereinafter, an embodiment of the present invention, Example 1, will be described with reference to Figures 1 to 11. For the sake of explanation, in the following description, the vertical direction shown in Figures 1, 2, 4 to 11 will be defined as the vertical direction, but it does not necessarily have to coincide with the vertical direction in the actual arrangement of the battery case 10.

[0019] (Battery case configuration) As shown in Figure 1, the battery case 10 of this embodiment houses a battery (e.g., a battery module) 20. The battery case 10 can house multiple batteries 20. As shown in Figure 2, the battery case 10 is, for example, roughly rectangular in plan view. The battery case 10 is attached to the underside S (outer surface under the floor) of the vehicle body B, as shown in Figure 3, while being supported from below by, for example, a bracket (not shown). The battery case 10 also houses electrical components such as a CPU and sensors.

[0020] As shown in Figure 1, the battery case 10 comprises a lower case 30 and an upper case 40. The battery case 10 houses the battery 20 inside when the lower case 30 and the upper case 40 are assembled. The battery 20 is placed on the inner bottom surface of the lower case 30. The upper case 40 covers and closes the opening of the lower case 30. The battery case 10 has a flange portion 12 formed on its outer circumferential surface. As shown in Figure 2, the flange portion 12 is provided around the entire circumference of the periphery of the battery case 10.

[0021] The lower case 30 is made of, for example, a metal material. As shown in Figure 1, the lower case 30 has a bottom wall 31, side walls 32, and a lower flange portion 33. The bottom wall 31 is in the shape of a rectangular plate. The side walls 32 rise from the periphery of the bottom wall 31. The lower flange portion 33 protrudes outward from the upper edge opening (upper end) of the side wall 32.

[0022] The upper case 40 is made of a metal material. As shown in Figure 1, the upper case 40 has a ceiling wall 41, a side wall 42, and an upper flange portion 43. The ceiling wall 41 is in the shape of a rectangular plate. The side wall 42 extends downward from the periphery of the ceiling wall 41. The upper flange portion 43 protrudes outward from the lower edge opening (lower end) of the side wall 42. The upper flange portion 43 is positioned above the lower flange portion 33.

[0023] (Flange structure) As shown in Figure 4, the flange portion 12 has a flat planar portion 14. The planar portion 14 is the portion where the lower flange portion 33 and the upper flange portion 43 overlap. The planar portion 14 has a planar shape that is perpendicular to the overlapping direction (vertical direction) of the lower case 30 and the upper case 40. The flange portion 12 is seam-welded in the planar portion 14. Specifically, in the planar portion 14, only the area outside (to the right in Figure 4) of the center of the protrusion direction D of the flange portion 12 (position shown as C in Figure 4) (outer welding area A1) is seam-welded and fixed. In the battery case 10, the area outside the center C of the protrusion direction D in the planar portion 14 is referred to as the seam-welded outer welding area A1. In the battery case 10, the area inside the center C of the protrusion direction D in the planar portion 14 is referred to as the seam-weldable inner weldable area A2. The internal weldable area A2 is not seam-welded and is not fixed. Even if the seam-welded areas of the battery case 10 are separated due to maintenance or other reasons, seam welding can be performed again in the internal weldable area A2.

[0024] Because seam welding is performed under pressure, the flatness accuracy of the joint surface of the flange portion 12 is improved, resulting in enhanced waterproofing. In addition, sealing members and fastening members (bolts, nuts, etc.) are not required when joining the flange portion 12, reducing parts costs and manufacturing costs.

[0025] As shown in Figure 4, a nugget 16 is formed at the weld location in the outer welding region A1. The nugget 16 is the portion where the molten part has cooled and solidified.

[0026] As shown in Figure 4, in the inner weldable region A2, a portion of the lower flange portion 33 (base end portion 33A) and a portion of the upper flange portion 43 (base end portion 43A) are arranged parallel to each other. Therefore, a mating surface is easily formed between the base end portion 33A and the base end portion 43A along the horizontal direction, and reliable welding can be performed by seam welding. The length of the inner weldable region A2 along the protrusion direction D is, for example, 13 mm.

[0027] As shown in Figure 4, a marker M is provided in the planar portion 14 near the center C in the overhang direction D. The marker M is provided on the upper surface of the upper flange portion 43. The marker M is, for example, a notched shape. The marker M may also be a mark made with ink or a sticker. The marker M may be provided only on the lower flange portion 33, or on both flange portions 33 and 34. The position near the center C in the overhang direction D is, for example, a position slightly offset from the center C in the overhang direction D (for example, 2 or 3 mm). By providing such a marker M, when attempting to cut off a seam-welded portion for maintenance, the cutting location can be identified by the marker M. Therefore, the flange portion 12 can be cut using the marker M as a reference.

[0028] As shown in Figure 4, the marker M is located slightly outward from the center C in the overhang direction D on the planar portion 14. That is, the marker M is located within the outer welding region A1, near the inner end of the outer welding region A1. Therefore, the cutting point of the flange portion 12 can be positioned outside the center C in the overhang direction D based on the position of the marker M. As a result, the seam welding point in the inner weldable region A2 can be moved away from the cutting point, enabling good welding.

[0029] As shown in Figure 2, the marker M consists of a continuous line around the entire circumference of the planar portion 14. The marker M is shaped along the outer edge of the planar portion 14 and is approximately rectangular in plan view. By cutting the flange portion 12 along the line of the marker M, a smooth and continuous cut can be achieved. For example, when using laser cutting, the marker M can be detected by a camera or the like to determine its position, and the position where the laser is irradiated (cutting position) can be precisely determined.

[0030] The battery case 10 (more specifically, the flange portion 12) is made of a zinc-containing metal. When a zinc-containing metal is irradiated with a laser, the zinc may melt, potentially creating a hole in that area. However, in this embodiment 1, since resistance welding, or seam welding, is used to join the flange portion 12, welding can be performed without creating a hole, even if the flange portion 12 contains zinc.

[0031] As shown in Figure 11, the outer region of the flange portion 12 (outer welding region A1) is bent downward. Specifically, the portion of the flange portion 12 including the seam-welded area is bent. The leading edge of the planar portion 14 in the outward direction D (for example, a part of the outer welding region A1) is bent downward. This reduces the size of the battery case. Such bent portions may be provided along the entire circumferential direction of the planar portion 14, or only on a portion of it.

[0032] (Method of manufacturing a battery case) As shown in Figures 5 and 6, the battery case 10 is manufactured by seam welding the outer welding area A1 of the flange portion 12. As shown in Figures 5 and 6, the electrodes 51 and 52 of the seam welding machine are disc-shaped. The flange portion 12 (more specifically, the outer welding area A1 of the planar portion 14) is welded while being sandwiched between the electrodes 51 and 52. Specifically, the flange portion 12 is continuously welded over its entire circumference by rotating and moving the electrodes 51 and 52 while applying current. The marker M may be formed before seam welding the outer welding area A1, or it may be formed after seam welding the outer welding area A1.

[0033] Furthermore, as shown in Figure 11, when bending the outer welding area A1 (the part including the seam-welded area) of the flange portion 12, jigs 61 and 62 are used as shown in Figure 10. For example, by supporting the lower surface of the inner weldable area A2 of the flat portion 14 with jig 61 and pressing the upper surface of the outer welding area A1 of the flat portion 14 downward with jig 62, the tip side of the flat portion 14 can be bent downward.

[0034] (How to maintain the battery case) This section describes how to open the battery case 10, as shown in Figure 4, for maintenance of internal components. First, the outer welded area A1, which is seam-welded in the flat portion 14, is separated. For example, the outer welded area A1 is separated by laser cutting. Specifically, in the battery case 10 shown in Figure 4, the flat portion 14 is cut at the mark M. As shown in Figure 7, the outer portion of the flat portion 14 is separated from the inner portion of the mark M in the protruding direction D of the flat portion 14. As a result, the battery case 10 is left with an inner weldable area A2 of the flat portion 14.

[0035] After performing maintenance on the internal components of the opened battery case 10, the remaining portion of the lower flange portion 33 and the remaining portion of the upper flange portion 43 are re-overlapped as shown in Figure 7.

[0036] Next, as shown in Figure 8, the inner weldable area A2 of the flange portion 12 is seam-welded. For example, the inner weldable area A2 is seam-welded in the same manner as the outer weldable area A1. A nugget 18 is formed at the weld location in the inner weldable area A2. In this way, as shown in Figure 9, the inner weldable area A2 is seam-welded, and the battery case 10 can be reused.

[0037] (Effects of this embodiment) The effects of this embodiment 1 are described below. In the battery case 10 of this embodiment 1, in the flat planar portion 14 where the lower flange portion 33 and the upper flange portion 43 of the flange portion 12 overlap, only the area outside the center C in the protrusion direction D of the flange portion 12 is seam-welded. Therefore, even if the seam-welded area is separated due to maintenance or the like, it becomes easier to re-weld the area inside the center C in the protrusion direction D of the planar portion 14 (inner weldable area A2). As a result, the battery case 10 can be reused, and costs can be reduced.

[0038] In the battery case 10 of this embodiment 1, a part of the lower flange portion 33 (base end portion 33A) and a part of the upper flange portion 43 (base end portion 43A) are arranged parallel to each other, so they can be reliably welded by seam welding.

[0039] In the battery case 10 of this embodiment 1, when attempting to cut off a seam-welded portion due to maintenance or other reasons, the cutting point can be identified by the mark M. Therefore, the flange portion 12 can be cut using the mark M as a reference.

[0040] In the battery case 10 of this embodiment 1, the cutting point of the flange portion 12 can be positioned outside the center C of the protrusion direction D based on the position of the mark M. Therefore, it becomes easier to move the seam welding point in the inner region (inner weldable region A2) away from the cutting point, enabling good welding.

[0041] In the battery case 10 of this embodiment 1, cutting the flange portion 12 along the line of the mark M allows for a clean and uninterrupted cut.

[0042] In the battery case 10 of this embodiment 1, since resistance welding, or seam welding, is used, welding can be performed without creating holes in the flange portion 12, even if it contains zinc, compared to laser welding.

[0043] In the battery case 10 of this embodiment 1, the outer welding area A1 of the flange portion 12 may be bent downward. This configuration allows for a reduction in the size of the battery case 10.

[0044] <Other examples> The present invention is not limited to the embodiments described above and in the drawings, and the following embodiments, for example, are also included in the technical scope of the present invention. (1) In the above embodiment 1, the flange portion had a shape that followed the horizontal direction around its entire circumference, but it may have other shapes. For example, as in the battery case 210 shown in Figure 12, the joining surface 212A of the lower flange portion 233 and the upper flange portion 243 of the flange portion 212 may include a curved surface 212B. The curved surface 212B is inclined with respect to the vertical direction. For example, the curved surface 212B is provided for the purpose of providing the connector 270. In such a configuration, since the flange portion 212 is joined by seam welding in which pressure welding is performed, a good joining can be achieved even if the joining surface 212A is curved. Consequently, the degree of freedom in the shape of the lower flange portion 33 and the upper flange portion 43 can be increased. (2) In the above embodiment 1, the flange portion 12 was provided around the entire circumference of the periphery of the battery case 10, but it may be provided only on a part of the circumferential direction. (3) In the above embodiment 1, the marker M was provided in the planar portion 14 at a position slightly outward from the center C in the protrusion direction D, but it may also be provided at the same position as the center C, or at a position slightly inward from the center C. (4) In the above embodiment 1, the marker M consisted of a continuous line around the entire circumference of the planar portion 14, but it may also be interrupted in part or perforated. (5) In the above example 1, the flange portion 12 was made of a metal containing zinc, but it does not have to contain zinc. (6) In the above embodiment 1, the tip of the flange portion 12 was bent downward, but it may be bent in other directions, such as upward. [Explanation of Symbols]

[0045] 10…Battery case 12…Flange section 14...Plane part 20... Battery 30...Lower case 33...Lower flange section 40… Upper case 43… Upper flange section 210...Battery case 212...Flange section 212A…Joint surface 212B...Curved surface 233...Lower flange section 243... Upper flange section A1…Outer welding area (the area outside the center of the flange's protrusion direction) A2...Inner weldable area (the area inside the center of the protrusion direction in the flat portion) M... Landmark

Claims

1. A battery case comprising a lower case and an upper case, wherein a battery is housed inside when the lower case and the upper case are assembled, and a flange portion is formed on the outer surface, The flange portion is In the lower case, the lower flange portion protruding from the upper edge opening, The upper case has an upper flange portion positioned above the lower flange portion, In the flat planar portion of the flange where the lower flange portion and the upper flange portion overlap, only the area outside the center in the protruding direction of the flange portion is seam-welded. The area inward from the center in the direction of the protrusion in the planar portion is a battery case that can be seam-welded.

2. In the region of the planar portion inward from the center in the direction of protrusion, a portion of the lower flange portion and a portion of the upper flange portion are arranged parallel to each other and are seam-weldable, as described in claim 1.

3. The battery case according to claim 2, wherein a marker is provided in the planar portion at a position near the center in the direction of protrusion.

4. The battery case according to claim 3, wherein the mark is located outside the center in the protruding direction on the planar portion.

5. The battery case according to claim 3 or 4, wherein the markings consist of a continuous line extending around the entire circumference of the planar portion.

6. The battery case according to any one of claims 1 to 4, wherein the flange portion is made of a metal containing zinc.

7. The battery case according to any one of claims 1 to 4, wherein the outer region of the flange portion is bent upward or downward.

8. The battery case according to any one of claims 1 to 4, wherein the joining surface between the lower flange portion and the upper flange portion includes a curved surface.

9. A method for maintaining a battery case according to any one of claims 1 to 4, The outer region that is seam-welded in the aforementioned planar portion is separated, A maintenance method for a battery case, comprising seam welding the area inward from the center in the protruding direction of the planar portion.

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