Current-carrying component for secondary battery and method of manufacturing the same

Abstract

To provide a current-carrying component for a secondary battery and a method of manufacturing the same, in which the left and right end faces perpendicular to the joint surface are made of different materials after the current-carrying component for the secondary battery is manufactured, and a joint surface for joining to other components can be secured without requiring reprocessing of the end surfaces, etc.SOLUTION: In an electrically conductive component 1 for a secondary battery having a first plate material 10 made of aluminum or an aluminum alloy and a second plate material 20 made of copper or a copper alloy, the first plate material 10 and the second plate material 20 have a solid-state welded joint at the interface where they are stacked in the thickness direction, and both the side end faces of the first plate material 10 and the second plate material 20 are smooth.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electric current-carrying part for use in a secondary battery mounted mainly in an automobile or the like, and a method for manufacturing the same. [Background technology]

[0002] The positive electrode of a lithium-ion battery is made of aluminum alloy foil, and the negative electrode is made of copper foil. Usually, these are connected in series or parallel, but when they are connected, the positive and negative electrodes are connected, so joining of the aluminum alloy and copper is necessary (see Patent Documents 1 and 2). The positive and negative electrodes may be directly connected, but when a bus bar (current-carrying part) is sandwiched between them, they are often welded using laser welding, with both sides of the current-carrying part being welded to the positive and negative electrodes, respectively. Since welding is more stable when the same type of material is used, it is desirable for the material of the current-carrying part to be copper on the positive electrode side and aluminum alloy on the negative electrode side. The simplest structure that satisfies this condition is a current-carrying part made of aluminum alloy material on the left side and copper alloy material on the right side, as shown in Figure 4. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6971990 [Patent Document 2] Patent No. 7289049 Summary of the Invention [Problem to be solved by the invention]

[0004] However, a feature of the butted aluminum alloy and copper current-carrying parts shown in Figure 4 is that the joint between the aluminum alloy and copper can only be secured to the thickness of the plate at most. This causes a problem that a sufficient joint area cannot be secured when the plate thickness is thin compared to the plate width.

[0005] Therefore, an object of the present invention is to provide an electrical-conductive component for a secondary battery, which can provide a wider joint than in the case of a butt joint as shown in Figure 4, even when the thickness is small relative to the plate width, and which can ensure a sufficient joint area, and a method for manufacturing the same. [Means for solving the problem]

[0006] Therefore, the present invention provides a current-carrying component for a secondary battery comprising a first plate material made of aluminum or an aluminum alloy and a second plate material made of copper or a copper alloy, in which the first plate material and the second plate material are laminated in the thickness direction and have a joint portion solid-phase-welded at the interface, and both the side end faces of the first plate material and the second plate material are smooth. In addition, the thickness of the first plate material is made thicker than the thickness of the second plate material. Alternatively, the second plate material may be formed into either an L-shape or an inverted L-shape in a cross-sectional view in the thickness direction.

[0007] In addition, the invention of a method for manufacturing an electrical conductive part for a secondary battery includes a first step of fixing a first plate material made of aluminum or an aluminum alloy in a state in which the first plate material is stacked above a second plate material made of copper or a copper alloy, and a second step of inserting a friction stir welding tool rotating from above the first plate material into the first plate material to join it to the second plate material after the first step.

[0008] Furthermore, in the case where one side of the second plate material is formed in an L-shape when viewed in cross section, the method includes a first step of stacking the first plate material on top of the second plate material formed in an L-shape and fixing an end face of the first plate material, and a second step of inserting a friction stir welding tool rotating from above the first plate material into the first plate material to join it to the second plate material after this first step. Effect of the Invention

[0009] The conductive component for a secondary battery of the present invention is a conductive component in which the left and right end faces perpendicular to the joint surface are made of different materials, and has the advantage that no re-processing of the end faces, etc. is required even after production, and a joint surface for joining to other components can be secured. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic cross-sectional view of a current-carrying component 1 for a secondary battery according to a first embodiment of the present invention. [Diagram 2] 2 is a schematic cross-sectional view showing a manufacturing state of the current-carrying component 1 for a secondary battery shown in FIG. 1. [Diagram 3] FIG. 4 is a schematic cross-sectional view showing a manufacturing state of an electric-conducting component 2 for a secondary battery according to a second embodiment of the present invention. [Figure 4] FIG. 1 is a schematic cross-sectional view of a conventional current-carrying component. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] A current-carrying component for a secondary battery according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a schematic cross-sectional view of a current-carrying component for a secondary battery 1 according to a first embodiment of the present invention. In the current-carrying component for a secondary battery 1 shown in FIG. 1, an aluminum alloy (first sheet material) 10 and a copper alloy (second sheet material) 20 are joined by shifting their positions when they are superimposed, and after joining, the copper alloy 20 is bent to form one end surface. This results in a current-carrying component whose both end surfaces have the same material as the positive and negative electrodes of a lithium-ion battery, respectively.

[0012] In addition, when the aluminum alloy 10 and the copper alloy 20 are overlapped as shown in FIG. 1, the joining area is maximized and the lapped portion of the aluminum alloy 10 and the copper alloy 20 can be secured, so that the joining area is larger than that in the case of butting as shown in FIG. 4.

[0013] Next, the manufacturing method of the current-carrying component for secondary batteries according to the first and second embodiments of the present invention will be described with reference to the drawings. Fig. 2 is a schematic cross-sectional view showing a manufacturing state of the current-carrying component for secondary batteries 1 according to the first embodiment of the present invention, and Fig. 3 is a schematic cross-sectional view showing a manufacturing state of the current-carrying component for secondary batteries 2 according to the second embodiment of the present invention.

[0014] During the manufacture of the current-carrying component for a secondary battery (first embodiment) 1 of the present invention, a first plate material 10 made of aluminum or an aluminum alloy and a second plate material 20 made of copper or a copper alloy are stacked in the thickness direction and fixed using a pressing jig 60, as shown in Fig. 2. In this state, the tip of a friction stir welding tool 50 rotating from above the first plate material 10 is inserted into the inside of the first plate material 10, whereby a solid-state welded joint is formed at the interface between the first and second plate materials stacked in the thickness direction, and the plates are integrated.

[0015] In addition, in the first embodiment shown in Figure 2, the side end face (left side of the figure) of the first plate material 10 is fixed by a pressing jig 60, so that expansion (deformation) of the plate material due to heat generated by friction stir (point) joining is suppressed and smoothness is maintained, and at the same time, one end face (left side of the figure) of the second plate material 20 is bent into an L-shape when viewed in cross section in the thickness direction, similarly ensuring the smoothness of the end face.

[0016] 3, the current-carrying component for a secondary battery (second embodiment) 2 of the present invention is fixed using a pressing jig 61 in a state in which the first plate material 11 and the second plate material 21 are stacked in the thickness direction. In this state, the tip of a friction stir welding tool 51 rotating from above the first plate material 11 is inserted into the inside of the first plate material 11. At this time, both end faces of the first plate material 11 are fixed in the width direction by the pressing jig 61.

[0017] Furthermore, the second plate material 21 is fixed in the thickness direction by a pressing jig 61 from above. After the joining is completed by the friction stir welding tool 51, one end face (the right side in FIG. 3) of the second plate material 21 can be bent at a substantially right angle to form an inverted L-shape as in the first embodiment shown in FIG.

[0018] 3, both end faces of the first plate material 11 are fixed in the width direction by the pressing jig 61, so expansion (deformation) of the plate material due to heat generated by friction stir (point) joining is suppressed and smoothness is maintained. Similarly, a portion that will become an end face on one side of the second plate material 21 is fixed by the pressing jig 61, and the end face of the second plate material 21 is bent into an L shape (or an inverted L shape) after joining of the first plate material 11 and the second plate material 21 is completed, so the smoothness of the end face of the second plate material 21 can also be ensured. [Explanation of symbols]

[0019] 1,2 Current-carrying parts for secondary batteries 10,11 1st plate material 20,21 2nd plate material 50,51 Friction stir welding tools

Claims

1. An electrically conductive component for a secondary battery comprising a first plate material made of aluminum or an aluminum alloy and a second plate material made of copper or a copper alloy, the thickness of the first plate material being greater than the thickness of the second plate material, the first plate material and the second plate material being stacked in the thickness direction have a solid-state welded joint at their interface, and both of the side end faces of the first plate material and the second plate material are smooth.

2. 2 . The current-carrying component for a secondary battery according to claim 1 , wherein the second plate member is formed in either an L-shape or an inverted L-shape when viewed in a cross section in a thickness direction.

3. 2. A method for manufacturing an electrical conductive component for a secondary battery as described in claim 1, comprising: a first step of fixing the first and second plate materials in a state in which the first plate material is stacked above the second plate material; and a second step of inserting a friction stir welding tool rotating from above the first plate material into the first plate material after the first step to join it to the second plate material.

4. 3. A method for manufacturing an electrical conductive component for a secondary battery as described in claim 2, comprising: a first step of stacking the first plate material on top of the second plate material formed in an L-shape and fixing an end face of the first plate material; and a second step of inserting a friction stir welding tool rotating from above the first plate material into the inside of the first plate material after the first step to join it to the second plate material.

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