Welded structure of battery can and cap, and battery cell to which this is applied.

Abstract

The present invention provides a welded structure for a battery can and a cap, and a battery cell to which this structure is applied. [Solution] The present invention relates to a welded structure for a battery can and a cap, and a battery cell to which the same is applied. The battery cell includes a can that includes a bottom member and a side wall member connected to the bottom member and extending in the axial direction, an electrode assembly housed inside the can, and a cap that covers an open end provided at one axial end of the side wall member. A terminal connection portion is provided on the radial outer edge of a current collector plate connected to the electrodes of the electrode assembly and positioned on the open end side, extending outward in the axial direction and contacting the inner circumferential surface of the side wall member to be electrically connected. With at least a portion of the terminal connection portion interposed between the inner circumferential surface of the side wall member and the outer circumferential surface of the cap in the axial direction, the inner circumferential surface of the side wall member and the outer circumferential surface of the cap are welded to form a welded portion.

Claims

1. A battery cell comprising a can including a side wall member extending in the axial direction, an electrode assembly housed inside the can, and a cap covering an open end provided at one axial end of the side wall member, A terminal connecting portion is provided on the radial outer edge of the current collector plate, which is connected to the electrode of the electrode assembly and positioned on the open end side. This terminal connecting portion extends outward in the axial direction and contacts the inner circumferential surface of the side wall member to provide an electrical connection. A welded portion is formed where the inner circumferential surface of the side wall member and the outer circumferential surface of the cap are welded together, with at least a portion of the terminal connecting portion in the axial direction interposed between the inner circumferential surface of the side wall member and the outer circumferential surface of the cap. The outer circumferential surface of the cap is in contact with the inner circumferential surface of the terminal connecting portion. The edge of the cap is provided with a butt joint extending in the axial direction such that its outer circumferential surface faces the inner circumferential surface of the side wall member in the radial direction. A curved surface portion with a convex curved shape on the axial side is connected to the axial inner end of the aforementioned butt joint portion. A battery cell in which the curved portion is in contact with the current collector plate.

2. The current collector plate is connected to the electrodes of the electrode assembly and has an electrode connecting portion that extends radially, The terminal connecting portion is positioned further outward in the radial direction than the electrode connecting portion. The terminal connecting portion and the electrode connecting portion are connected via a bent portion provided at the lower end of the terminal connecting portion, which changes the extending direction of the current collector plate. The battery cell according to claim 1.

3. The side wall member extends further outward in the axial direction than the terminal connection portion of the current collector plate. The battery cell according to claim 1 or 2.

4. The inner diameter of the inner surface of the section of the side wall member that extends further outward in the axial direction than the terminal connection portion of the current collector plate is larger than the inner diameter of the inner surface of the terminal connection portion. The battery cell according to claim 3.

5. The aforementioned butt joint extends further outward in the axial direction than the terminal connection portion of the current collector plate. The battery cell according to claim 1 or 2.

6. The outer diameter of the outer surface of the section of the current collector plate that extends further outward in the axial direction than the terminal connection portion at the abutting portion is smaller than the outer diameter of the outer surface of the terminal connection portion. The battery cell according to claim 1 or 2.

7. The welded portion is formed by welding at least the axial outer edge of the inner circumferential surface of the side wall member, the axial outer edge of the outer circumferential surface of the butt joint portion, and the axial outer edge of the terminal connecting portion. The battery cell according to claim 1 or 2.

8. The axial inner end of the curved portion interferes with the current collector plate in the axial direction, thereby restricting the insertion depth of the cap into the open end. The battery cell according to claim 1 or 2.

9. A receiving portion is provided radially inward from the curved portion of the cap, which extends in a radially flattened manner. The curved portion and the receiving portion are connected via a first inclined portion that extends outward in the axial direction as it moves inward in the radial direction. The battery cell according to claim 1 or 2.

10. The axial outer surface of the receiving portion protrudes further outward in the axial direction than the abutting portion with the side wall member. The battery cell according to claim 9.

11. A radially extending centering portion is provided radially inward from the receiving portion of the cap. The receiving portion and the centering portion are connected via a second inclined portion that extends inward in the axial direction as it moves inward in the radial direction. The battery cell according to claim 9.

12. The second inclined portion has a gentler incline than the first inclined portion. The battery cell according to claim 11.

13. The axial inner surface of the centering portion is positioned further outward in the axial direction than the axial inner end of the curved portion. The battery cell according to claim 11.

14. The axial outer edge of the terminal connecting portion is positioned further inward in the axial direction than the axial outer edge of the side wall member and the axial outer edge of the butt joint portion. The battery cell according to claim 1 or 2.

15. A method for manufacturing a battery cell according to claim 1 or 2, During the stage of inserting the current collector plate into the can, the outer circumferential surface of the terminal connecting portion of the current collector plate contacts the inner circumferential surface of the side wall member; The step of inserting the cap into the can such that the outer surface of the cap contacts the inner surface of the terminal connecting portion of the current collector plate inserted into the can; and The step includes irradiating a laser in the axial direction into the region where the outer circumferential surface of the side wall member and the inner circumferential surface of the can face each other to form a welded portion; A method for manufacturing battery cells.

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