Current-carrying component for secondary battery

Abstract

A current-carrying component 100 for a secondary battery according to the present invention is formed of a plurality of metal foil materials 11-15 laminated in a thickness direction. The current-carrying component for a secondary battery has two or more through holes H1 in the thickness direction of the plurality of metal foil materials 11-15. On an inner peripheral surface of the through holes H1, a joint part Y1 where the plurality of metal foil materials 11-15 are solid-phase joined is provided, and a step d1 is provided on one end side of the joint part Y1. Further, five or more metal foil materials may be used for the current-carrying component 100 for a secondary battery so that the thickness per sheet can be 0.21 mm or less.

Description

Current-carrying parts for secondary batteries

[0001] The present invention relates to an electric component for use in a secondary battery mounted mainly on an automobile or the like.

[0002] Current-carrying components formed from two or more sheets or foils, particularly current-carrying components for secondary batteries in automobiles and the like, are also called bus bars and are made of highly conductive materials such as aluminum alloys and copper alloys.

[0003] Patent No. 6971990

[0004] However, in some cases where bolt holes (through holes) are provided in current-carrying components formed by laminating multiple metal foil materials to fasten these parts to other components, it is necessary to improve the contact between the metal foil materials to reduce resistance during current flow, which means that the components need to be rigid enough to withstand the tightening load when fastened using bolts.

[0005] For example, when joining multiple metal foil materials together by crimping, the contact between the metal foils is low, which causes distortion between the foil materials and makes it difficult to adapt to the tightening load. Also, when joining multiple metal foil materials together by laser welding, if the metal foils are misaligned during joining, the welding work becomes difficult and the smoothness of the joining surface cannot be ensured.

[0006] Therefore, an object of the present invention is to provide an electrically conductive component for a secondary battery that is made of metal foil material and has a bolt hole (through hole), and that can ensure the rigidity of the bolt hole while also ensuring the smoothness required for a bolt part.

[0007] The current-carrying component for a secondary battery of the present invention is formed by stacking multiple sheets of metal foil material in the thickness direction, and has two or more through holes formed in the current-carrying component in the thickness direction of the multiple metal foil materials, and a joint where the multiple metal foil materials are solid-state welded to each other on the inner surface of the through hole, with a step formed on one end side of the joint.

[0008] Alternatively, five or more sheets of metal foil material may be used, with each sheet having a thickness of 0.21 mm or less. In this case, the material of the metal foil material may be any of aluminum, aluminum alloy, copper, and copper alloy.

[0009] The current-carrying component for a secondary battery of the present invention is made up of a plurality of metal foil materials and has two or more through holes in its thickness direction, the inner surfaces of which have joints formed by solid-state welding of the plurality of metal foil materials together, and a step on one end of the joint, which ensures high contact between the metal foils and maintains rigidity while ensuring electrical conductivity as a current-carrying component and also providing locations for fastening components such as bolts, thereby achieving the effect of being able to fully adapt to the fastening load of other components using bolts, etc.

[0010] 1 is a schematic cross-sectional view of a current-carrying component 100 for a secondary battery according to a first embodiment of the present invention; 2 is a schematic cross-sectional view of a current-carrying component 200 for a secondary battery according to a second embodiment of the present invention; 3 is a schematic cross-sectional view of a current-carrying component 300 for a secondary battery according to a third embodiment of the present invention; 4 is an enlarged view of a portion A shown in FIG. 4;

[0011] Current-carrying components for secondary batteries according to first to third embodiments of the present invention will be described with reference to the drawings. Fig. 1 shows a schematic cross-sectional view of one through hole H1 in a current-carrying component for secondary batteries 100 according to the first embodiment of the present invention, Fig. 2 shows a schematic cross-sectional view of one through hole H2 in a current-carrying component for secondary batteries 200 according to a second embodiment of the present invention, and Fig. 3 shows a schematic cross-sectional view of one through hole H3 in a current-carrying component for secondary batteries 300 according to a third embodiment of the present invention. Fig. 4 shows an overall view of a friction stir welding tool T used in fabricating the current-carrying components for secondary batteries 200, 300 according to the second and third embodiments of the present invention shown in Figs. 2 and 3, and Fig. 5 shows an enlarged view of the tip portion (part A in Fig. 4) of the friction stir welding tool T.

[0012] A secondary battery current-carrying component 100 (first embodiment) of the present invention is formed by stacking a plurality of metal foil materials 10 (11, 12, 13, 14, 15) in the thickness direction as shown in Fig. 1. This secondary battery current-carrying component 100 has a through hole H1 as shown in Fig. 1, and the inner circumferential surface of the through hole H1 in this embodiment is formed as a joint Y1 where five metal foil materials 11, 12, 13, 14, 15 are solid-state welded to one another (integrated structurally and morphologically).

[0013] As shown in FIG. 1 , the secondary battery current-carrying component (first embodiment) 100 of the present invention has an annular protrusion 16 protruding in the thickness direction of the metal foil material 10 on one end side of the joint Y1, i.e., on the side of the metal foil material 11 in the outermost layer. The annular protrusion 16 forms a step d1 between the metal foil material 11 and the outermost layer. The outermost surface 16F of the protrusion 16 is flat, allowing for stable installation of components such as bolts, nuts, and washers when fastening the secondary battery current-carrying component (first embodiment) 100 of this embodiment to other components using bolts or the like. The inner circumferential surface of the protrusion 16 and the inner circumferential surface of the through hole H1 are continuously connected. That is, the inner circumferential surface of the protrusion 16 and the inner circumferential surface of the through hole H1 form a single, substantially cylindrical inner circumferential surface.

[0014] Next, a secondary battery current-carrying component (second embodiment) 200 of the present invention is formed in a form in which a plurality of metal foil materials 20 (21, 22, 23, 24, 25) are stacked in the thickness direction, as in the case of the first embodiment described above, as shown in Fig. 2. This secondary battery current-carrying component 200 also has a through hole H2 as shown in Fig. 2, and the inner circumferential surface of the through hole H2 is formed as a joint Y2 in which five metal foil materials 21, 22, 23, 24, 25 are solid-state welded (integrated structurally and morphologically) in this embodiment as well.

[0015] As shown in FIG. 2 , the secondary battery current-carrying component (second embodiment) 200 of the present invention has an annular protrusion 26 on one end side of the joint Y2, i.e., on the side of the metal foil material 21 in the outermost layer, as in the first embodiment described above. By providing this annular protrusion 26, a step is formed between the metal foil material 21 in the outermost layer. Furthermore, as shown in FIG. 2 , the annular protrusion 26 of the secondary battery current-carrying component (second embodiment) 200 of this embodiment also has a step d2 on the inside (the inner surface side of the through hole H2). A portion of the inner circumferential surface of the protrusion 26 and the inner circumferential surface of the through hole H2 are continuously connected to form a single, substantially cylindrical inner circumferential surface. Furthermore, the inner circumferential surface of the protrusion 26 is formed to protrude above the surface of the metal foil material 20. That is, the step d2 on the inner peripheral surface side of the annular convex portion 26 is smaller in dimension than the step on the outer peripheral surface side of the annular convex portion 26.

[0016] A step d2 is also provided on the inner surface of the protrusion 26, thereby forming a flat surface 27. That is, when the current-carrying component for a secondary battery (second embodiment) 200 of this embodiment is fastened to another component using a bolt or the like, components such as bolts, nuts, and washers can be stably installed on the flat surface 27. Furthermore, a flange portion is formed on the outside (outer periphery) of the flat surface 27, which results in easy positioning of components such as bolts, nuts, and washers.

[0017] The flat surface 27 of the current-carrying component 200 for a secondary battery shown in FIG. 2 can be formed using the tip portion of the friction stir welding tool T shown in FIG. 4, i.e., the flat portion F corresponding to the connection portion between the small diameter portion T1 and the large diameter portion T2 of the tip of the friction stir welding tool T.

[0018] Finally, a current-carrying component for a secondary battery (third embodiment) 300 of the present invention is formed in a form in which a plurality of metal foil materials 30 (31, 32, 33, 34, 35) are laminated in the thickness direction, as in the case of the first embodiment described above, as shown in Fig. 3. This current-carrying component for a secondary battery 300 also has a through hole H3 as shown in Fig. 3, and the inner surface of the through hole H3 is formed as a joint Y3 in which five metal foil materials 31, 32, 33, 34, 35 are solid-state welded (integrated structurally and morphologically) in this embodiment as well.

[0019] 3, a secondary battery current-carrying component (third embodiment) 300 of the present invention has an annular protrusion 36 on one end side of the joint Y3, i.e., on the side of the outermost metal foil material 31, as in the first and second embodiments. The provision of this annular protrusion 36 creates a step between the outermost metal foil material 31, and therefore a flat surface is formed on the outermost surface of the annular protrusion 36, allowing components such as bolts, nuts, and washers to be stably installed. Furthermore, as in the second embodiment, a step d3 of the through hole H3 is further provided inside the protrusion 36 of the secondary battery current-carrying component (third embodiment) 300 of this embodiment, as shown in FIG. 3.

[0020] A step d3 is also provided on the inside of the protrusion 36 (the inner surface side of the through hole H3), forming a flat surface 37. In other words, when the secondary battery current-carrying component (third embodiment) 300 of this embodiment is fastened to another component using a bolt or the like, components such as bolts, nuts, and washers can be stably installed on the flat surface 37. Furthermore, a flange portion (not shown) is formed on the outside (outer periphery) of the flat surface 37, which facilitates the positioning of components such as bolts, nuts, and washers. In this embodiment, the surface of the flat surface 37 is recessed relative to the surface of the metal foil material 30. In other words, the step d3 on the inner periphery of the annular protrusion 36 is larger than the step on the outer periphery of the annular protrusion 36.

[0021] The flat surface 37 of the current-carrying component 300 for a secondary battery shown in FIG. 3 can be formed using the tip portion of the friction stir welding tool T shown in FIG. 4, i.e., the flat portion F corresponding to the connection portion between the small diameter portion T1 and the large diameter portion T2 of the tip of the friction stir welding tool T.

[0022] When the metal foil material is aluminum or an aluminum alloy, the thickness of each sheet may be 0.2 mm or less (JIS H4160, H4170).When the metal foil material is copper or a copper alloy, the thickness of each sheet may be 0.21 mm or less (JIS C6515).

[0023] 10, 20, 30 Metal foil material 11 to 15 Metal foil material 21 to 25 Metal foil material 31 to 35 Metal foil material 100, 200, 300 Current-carrying part for secondary battery 16, 26, 36 Convex portion 16F, 27, 37 Flat surface F Flat portion H1, H2, H3 Through hole T Friction stir welding tool T1 Small diameter portion T2 Large diameter portion Y1, Y2, Y3 Joint portion d1, d2, d3 Step (dimension)

Claims

1. A conductive component for a secondary battery formed by stacking multiple sheets of metal foil material in the thickness direction, the conductive component for a secondary battery having two or more through holes in the thickness direction of the multiple sheets of metal foil material, the inner surface of the through hole having a joint where the multiple sheets of metal foil material are solid-state welded to each other, and a circular convex portion provided on one end side of the joint.

2. The current-carrying component for a secondary battery according to claim 1, further comprising a step on the inside of the annular protrusion.

3. The current-carrying part for a secondary battery according to claim 1, characterized in that there are five or more sheets of said metal foil material, each sheet having a thickness of 0.21 mm or less.

4. The current-carrying part for a secondary battery according to claim 2, characterized in that there are five or more sheets of said metal foil material, each sheet having a thickness of 0.21 mm or less.

5. A current-carrying part for a secondary battery according to any one of claims 1 to 5, characterized in that the metallic foil material is any one of aluminum, an aluminum alloy, copper, and a copper alloy.

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