Battery case and welding method thereof

Abstract

To provide a technology capable of obtaining a structure in which the faces of a hexahedral battery case are firmly joined together.SOLUTION: A hexahedral battery case may have four vertical sides extending in a vertical direction, four horizontal sides extending in a horizontal direction, and four depth sides extending in a depth direction. At least one vertical side of the four vertical sides, at least one horizontal side of the four horizontal sides, and at least one depth side of the four depth sides may be welded in a single welding step, thereby joining adjacent faces via the welded sides.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a battery case and a welding method thereof. [Background technology]

[0002] Patent Document 1 discloses a hexahedral battery case. The battery case of Patent Document 1 has four vertical sides extending in the vertical direction, four horizontal sides extending in the horizontal direction, and four depth sides extending in the depth direction. The battery case of Patent Document 1 also has a main body and a lid body welded to the main body. The main body has a bottom surface of the hexahedral battery case and four side surfaces extending from the four sides of the bottom surface toward the lid body. In the battery case of Patent Document 1, the horizontal sides of the main body are welded to join the adjacent bottom surface and side surfaces via the horizontal sides. In the battery case of Patent Document 1, the side surfaces of the main body are welded. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-8665 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the battery case of Patent Document 1, the process of welding the horizontal sides of the body and the process of welding the side are separate, so welding marks are formed from each process. If this happens, the strength of the joints may be reduced due to the separate welding marks. This specification provides a technology that can obtain a structure in which the faces of a hexahedral battery case are firmly joined together. [Means for solving the problem]

[0005] In a first aspect of the present technology, a hexahedral battery case may include four vertical sides extending in a vertical direction, four horizontal sides extending in a horizontal direction, and four depth sides extending in a depth direction. At least one of the four vertical sides, at least one of the horizontal sides, and at least one of the depth sides may be welded in a single welding step to join adjacent faces via the welded sides.

[0006] With this configuration, the three edges in the vertical, horizontal, and depth directions are welded in a single welding process, which prevents the weld marks from splitting, and produces a battery case in which adjacent surfaces are firmly joined together via the weld edges.

[0007] In a second aspect, the battery case according to the first aspect may include a main body and a lid welded to the main body. The main body may include a hexahedral bottom surface of the battery case and a pair of first side surfaces extending from opposite sides of the bottom surface toward the lid. The lid may include a hexahedral top surface of the battery case and a pair of second side surfaces extending from opposite sides of the top surface toward the main body.

[0008] According to this configuration, the main body and the lid, which are separated from each other, can be firmly joined together in a small number of steps.

[0009] In a third aspect, in the first aspect, the hexahedral battery case may be formed of a single T-shaped member when unfolded before each side is welded. The bottom surface, top surface, and four side surfaces between the bottom surface and the top surface of the hexahedral battery case may be formed by bending the T-shaped member.

[0010] According to this configuration, a strong battery case can be obtained from a single unseparated T-shaped member.

[0011] In a fourth aspect, in any one of the first to third aspects, a start point and an end point of the portion to be welded in one welding step may overlap. With this configuration, the entire portion can be joined in one welding step.

[0012] A fifth aspect of the present technology relates to a method for welding a hexahedral battery case that houses an electrode assembly. The battery case may have four vertical sides extending in a vertical direction, four horizontal sides extending in a horizontal direction, and four depth sides extending in a depth direction. The welding method may include welding at least one of the four vertical sides, at least one of the horizontal sides, and at least one of the depth sides in a single welding step, thereby joining adjacent surfaces via the welded sides.

[0013] According to this configuration, a battery case can be obtained in which adjacent faces are firmly joined via welded edges. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a perspective view of a battery case according to the first embodiment. [Diagram 2] FIG. 2 is an exploded perspective view of the battery case according to the first embodiment. [Diagram 3] FIG. 11 is an exploded view of a battery case according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] (First Example) A first embodiment will be described with reference to the drawings. As shown in Fig. 1 and Fig. 2, a battery 100 of the first embodiment includes a hexahedral battery case 2, an electrode body 50 housed in the battery case 2, and a pair of terminals 60, 60 attached to the battery case 2. The battery 100 is, for example, a secondary battery such as a lithium ion battery or a nickel-metal hydride battery. The battery 100 is mounted, for example, on an electrically powered vehicle (for example, an electric vehicle or a hybrid vehicle).

[0016] The battery case 2 includes a main body 10 and a lid 20. The battery case 2 is configured by combining the main body 10 and the lid 20. The main body 10 and the lid 20 are joined by, for example, welding. The battery case 2 accommodates an electrode assembly 50 and an electrolyte in a space surrounded by the main body 10 and the lid 20. The electrode assembly 50 is configured, for example, by winding a sheet-like member (not shown) including a positive electrode, a negative electrode, and a separator.

[0017] The body 10 of the battery case 2 is made of a metal such as an aluminum alloy. The body 10 has a bottom surface 12 and a pair of short side surfaces 14, 14. The bottom surface 12 and the pair of short side surfaces 14, 14 are integrally formed.

[0018] The bottom surface 12 is configured in a rectangular shape and has a pair of long sides 12a, 12a and a pair of short sides 12b, 12b. Each of the long sides 12a (an example of a depth side) extends in the depth direction, and each of the short sides 12b (an example of a horizontal side) extends in the horizontal direction.

[0019] The pair of short side surfaces 14, 14 extend upward from a pair of short sides 12b, 12b of the bottom surface 12. Each short side surface 14 extends from the bottom surface 12 of the main body 10 toward the top surface 22 of the lid body 20. Each short side surface 14 is configured in a rectangular shape and includes a pair of long sides 14a, 14a and a pair of short sides 14b, 14b. Each long side 14a (an example of a vertical side) extends in the vertical direction, and each short side 14b (an example of a horizontal side) extends in the horizontal direction.

[0020] The lid 20 of the battery case 2 is made of a metal such as an aluminum alloy. The lid 20 has a top surface 22 and a pair of long side surfaces 24, 24. The top surface 22 and the pair of long side surfaces 24, 24 are integrally formed.

[0021] The top surface 22 faces the bottom surface 12 of the main body 10. The top surface 22 is configured in a rectangular shape and has a pair of long sides 22a, 22a and a pair of short sides 22b, 22b. Each of the long sides 22a (an example of a depth side) extends in the depth direction, and each of the short sides 22b (an example of a horizontal side) extends in the horizontal direction.

[0022] The pair of long side surfaces 24, 24 extend downward from a pair of long sides 22a, 22a of the top surface 22. Each long side surface 24 extends from the top surface 22 of the lid body 20 toward the bottom surface 12 of the main body 10. The electrode body 50 is disposed between the pair of long side surfaces 24, 24. Each long side surface 24 is configured in a rectangular shape and includes a pair of long sides 24a, 24a and a pair of short sides 24b, 24b. Each long side 24a (an example of a depth side) extends in the depth direction, and each short side 24b (an example of a vertical side) extends in the vertical direction.

[0023] A pair of terminals 60, 60 is provided on the top surface 22 of the lid body 20. Each terminal 60 is attached to the top surface 22 in a state insulated from the lid body 20. For example, an insulating member is disposed between each terminal 60 and the top surface 22. The pair of terminals 60, 60 are electrically connected to the positive electrode and negative electrode (not shown) of the electrode body 50, respectively.

[0024] In the above-described battery case 2 and battery 100, before the main body 10 and the lid body 20 of the battery case 2 are combined, the electrode body 50 housed in the battery case 2 is housed between the pair of long sides 24, 24 of the lid body 20 on which the terminal 60 is provided. Thereafter, the main body 10 and the lid body 20 are combined with the electrode body 50 housed between the pair of long sides 24, 24 of the lid body 20. With the main body 10 and the lid body 20 combined, they are welded together.

[0025] Next, a method for welding the battery case 2 will be described. When welding the main body 10 and the lid 20, the bottom surface 12 of the main body 10 is welded to the pair of long side surfaces 24, 24 of the lid 20. In addition, the pair of short side surfaces 14, 14 of the main body 10 is welded to the pair of long side surfaces 24, 24 of the lid 20. In addition, the pair of short side surfaces 14, 14 of the main body 10 is welded to the top surface 22 of the lid 20.

[0026] The welded joint starts from an intersection P (i.e., the corner between the bottom surface 12, the short side surface 14, and the long side surface 24) of the lower short side surface 12b of the short side surface 14 of the main body 10 and the lower long side surface 24a of the long side surface 24 of the lid 20. The welded joint starts from the intersection point P and is performed along the path shown by the arrow in FIG. 1, and ends at the starting point, the intersection point P. The welded joint is performed in one welding process from the intersection point P (starting point) to the intersection point P (end point). The starting point (intersection P) and the end point (intersection P) of the welding process overlap.

[0027] More specifically, in the welding process, starting from the intersection point P, the angle between the short side 14 of the main body 10 and the long side 24 of the lid 20 (i.e., the long side 14a of the short side 14 and the short side 24b of the long side 24) is welded as shown by the arrow (first step). Then, the angle between the short side 14 of the main body 10 and the top surface 22 of the lid 20 (i.e., the short side 14b of the short side 14 and the short side 22b of the top surface 22) is welded (second step). Then, the angle between the short side 14 of the main body 10 and the long side 24 of the lid 20 (i.e., the long side 14a of the short side 14 and the short side 24b of the long side 24) is welded (third step).

[0028] Next, the corner between the bottom surface 12 of the body 10 and the long side surface 24 of the lid 20 (i.e., the long side 12a of the bottom surface 12 and the long side 24a of the long side surface 24) is welded (fourth step). Next, the corner between the short side surface 14 of the body 10 and the long side surface 24 of the lid 20 (i.e., the long side 14a of the short side surface 14 and the short side 24b of the long side surface 24) is welded (fifth step). Next, the corner between the short side surface 14 of the body 10 and the top surface 22 of the lid 20 (i.e., the short side 14b of the short side surface 14 and the short side 22b of the top surface 22) is welded (sixth step).

[0029] Next, the corner between the short side 14 of the body 10 and the long side 24 of the lid 20 (i.e., the long side 14a of the short side 14 and the short side 24b of the long side 24) is welded (seventh step). Next, the corner between the bottom surface 12 of the body 10 and the long side 24 of the lid 20 (i.e., the long side 12a of the bottom surface 12 and the long side 24a of the long side 24) is welded (eighth step). In the welding joint, the above-mentioned first to eighth steps are continuously performed in one welding step.

[0030] (effect) The first embodiment has been described above. As described above, in the battery case 2 of the first embodiment, the four vertical sides (the pair of long sides 14a of the pair of short side surfaces 14 and the pair of short sides 24b of the pair of long side surfaces 24) of the hexahedral battery case 2, the two horizontal sides (the upper short sides 14b of the pair of short side surfaces 14 and the pair of short sides 22b of the top surface 22) and the two depth sides (the pair of long sides 12a of the bottom surface 12 and the long sides 24a of the pair of long side surfaces 24) are welded in one welding process. As a result, adjacent surfaces (the short side surfaces 14 and the long side surfaces 24, the short side surfaces 14 and the top surface 22, and the long side surfaces 24 and the bottom surface 12) are joined via the welded sides. In addition, the start point (intersection P) and the end point (intersection P) of the parts welded in one welding process overlap.

[0031] According to this configuration, the edges in the three directions, the vertical direction, the horizontal direction, and the depth direction, are welded in a single welding process, so that it is possible to prevent the weld marks from splitting and obtain a battery case 2 in which adjacent faces are firmly joined via the weld edges. Also, the entire case can be joined in a single welding process.

[0032] The battery case 2 of the first embodiment includes a main body 10 and a lid 20, and the main body 10 includes a bottom surface 12 of the battery case 2 and a pair of short side surfaces 14, 14 (an example of first side surfaces) extending from opposite sides of the bottom surface 12 toward the lid 20. The lid 20 includes a top surface 22 of the battery case 2 and a pair of long side surfaces 24, 24 (an example of second side surfaces) extending from opposite sides of the top surface 22 toward the main body 10.

[0033] According to this configuration, the main body 10 and the lid body 20, which are separated, can be firmly joined in a few steps. Furthermore, at the stage where the main body 10 and the lid body 20 are combined, the wide surface (long side surface) of the electrode body 50 housed in the battery case 2 is covered by the pair of long side surfaces 24, 24 of the lid body 20 and is not exposed to the outside. Therefore, the wide surface of the electrode body 50 housed in the battery case 2 can be protected.

[0034] (Second Example) A second embodiment will be described with reference to the drawings. In the following description, detailed description of the same configuration as in the above description may be omitted.

[0035] 3, in an unfolded state before the sides are welded, the battery case 2 of the second embodiment is composed of a single T-shaped member 70. The battery case 2 is formed by bending the T-shaped member 70 to form the bottom surface 12, the top surface 22, and four side surfaces between the bottom surface 12 and the top surface 22 (a pair of short side surfaces 14, 14 and a pair of long side surfaces 24, 24).

[0036] The T-shaped member 70 has a pair of (two) first protrusions 71 protruding from the short side 12b of the portion constituting the bottom surface 12 of the battery case 2, and one second protrusion 72 protruding from the long side 12a of the portion constituting the bottom surface 12. The two first protrusions 71 correspond to the portions constituting the two short side surfaces 14 of the battery case 2. The second protrusion 72 corresponds to the portions constituting the two long side surfaces 24 and one top surface 22 of the battery case 2. In the second embodiment, welding is performed in a state in which the shape of the battery case 2 has been formed by bending the T-shaped member 70.

[0037] In the welding of the battery case 2 in the second embodiment, welding starts from the intersection P, as in the first embodiment (see FIG. 1). In the second embodiment, the first to seventh steps described in the first embodiment are performed in a single welding process. In the second embodiment, the battery case 2 is configured with the T-shaped member 70 in the unfolded state, so the eighth step is not performed.

[0038] The above describes the second embodiment. According to the second embodiment, a strong battery case 2 can be obtained from a single unseparated T-shaped member 70.

[0039] (Modification) In the first embodiment, the main body 10 has a pair of short side surfaces 14, 14, and the cover 20 has a pair of long side surfaces 24, 24, but this configuration is not limited to this. In a modified example, the main body 10 may have a pair of long side surfaces 24, 24, and the cover 20 may have a pair of short side surfaces 14, 14.

[0040] In the first embodiment, the first to eighth steps are performed in a single welding step, but this is not limited to the configuration. In the second embodiment, the first to seventh steps are performed in a single welding step, but this is not limited to the configuration. In a modified example, some of the first to eighth steps (or the seventh step) may be performed in a single welding step. For example, the second, third, and fourth steps may be performed in a single welding step. With this configuration, at least one vertical side, at least one horizontal side, and at least one depth side of the hexahedral battery case 2 are welded and joined in a single welding step.

[0041] The vertical direction, horizontal direction, and depth direction in the first and second embodiments are merely examples and can be interchanged.

[0042] Although specific examples of the present invention have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives is itself technically useful. [Explanation of symbols]

[0043] 2: battery case, 10: main body, 12: bottom surface, 14: short side surface, 20: lid body, 22: top surface, 24: long side surface, 50: electrode body, 60: terminal, 70: member, 100: battery

Claims

1. A hexahedral battery case, The device has four vertical sides extending in a vertical direction, four horizontal sides extending in a horizontal direction, and four depth sides extending in a depth direction, A battery case in which at least one of the four vertical sides, at least one of the horizontal sides, and at least one of the depth sides are welded in a single welding process, thereby joining adjacent surfaces via the welded sides.

2. The battery case according to claim 1 , The container has a main body and a cover that is welded to the main body. The main body includes a bottom surface of the battery case having a hexahedral shape and a pair of first side surfaces extending from opposite sides of the bottom surface toward the lid body, The lid body includes a hexahedral top surface of the battery case and a pair of second side surfaces extending from opposite sides of the top surface toward the main body.

3. The battery case according to claim 1 , The hexahedral battery case is composed of a single T-shaped member when unfolded before each side is welded, and the bottom, top, and four side surfaces of the hexahedral battery case between the bottom and top are formed by bending the T-shaped member.

4. The battery case according to claim 1 , A battery case where the start and end points of the parts to be welded in a single welding process overlap.

5. A method for welding a hexahedral battery case that houses an electrode assembly, comprising the steps of: The battery case has four vertical sides extending in a vertical direction, four horizontal sides extending in a horizontal direction, and four depth sides extending in a depth direction, This battery case has adjacent surfaces joined via welded edges by welding at least one of the four vertical edges, at least one of the horizontal edges, and at least one of the depth edges in a single welding process.

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