Secondary battery and separator

Abstract

This secondary battery comprises an electrode group and a nonaqueous electrolyte. The electrode group includes a positive electrode, a negative electrode facing the positive electrode, and a separator disposed between the positive electrode and the negative electrode. This separator includes a base material and a spacer. The spacer includes a linearly protruding part. The linearly protruding part includes both end parts in the length direction of the linearly protruding part, and a main part other than the both end parts. In at least one end part E of the both end parts, the width of the linearly protruding part is smaller than that of the main part.

Claims

1. A secondary battery comprising an electrode group and a non-aqueous electrolyte, wherein the electrode group includes a positive electrode, a negative electrode facing the positive electrode, and a separator disposed between the positive electrode and the negative electrode, the separator comprises a base material and a spacer, the spacer includes a linear projection, the linear projection has both ends in the longitudinal direction of the linear projection and a main portion other than the two ends, and in a plan view of the separator, at least one end E of the two ends has a width of the linear projection that is smaller than the main portion.

2. The secondary battery according to claim 1, wherein at the end E, the width of the line-shaped protrusion decreases continuously as it moves away from the main part.

3. The secondary battery according to claim 1, wherein the linear protrusion is formed along a predetermined pattern, the predetermined pattern having the arrangement region and a defect region in which the linear protrusion is not arranged in a part of the longitudinal direction in which the linear protrusion extends, and the linear protrusion has the end E near the defect region.

4. The secondary battery according to claim 3, wherein the defect regions are arranged on both sides in the longitudinal direction of the arrangement region, the linear protrusions have ends E near the defect regions on both sides in the longitudinal direction of the main portion, and the ratio of the total length LE of the ends E to the length L0 of the linear protrusions: LE / L0 is 0.2 or more.

5. The secondary battery according to claim 4, wherein the LE / L0 is 0.4 or greater.

6. The secondary battery according to any one of claims 1 to 4, wherein the spacer includes a plurality of linear protrusions, and at least half of the total number of the plurality of linear protrusions have the end portion E.

7. The secondary battery according to claim 6, wherein 4 / 5 or more of the total number of the plurality of linear protrusions have the end portion E.

8. The secondary battery according to any one of claims 1 to 4, wherein the negative electrode is an electrode in which lithium metal is deposited during charging and the lithium metal dissolves in the non-aqueous electrolyte during discharge.

9. A separator for a secondary battery, wherein the separator comprises a base material and a spacer, the spacer includes a linear projection, the linear projection has both ends in the longitudinal direction of the linear projection and a main portion other than the two ends, and in a plan view of the separator, at least one end E of the two ends has a width of the linear projection that is smaller than the main portion.

10. The separator according to claim 9, wherein at the end E, the width of the line-shaped protrusion decreases continuously as it moves away from the main part.

11. The separator according to claim 9, wherein the linear protrusion is formed along a predetermined pattern, the predetermined pattern having the arrangement region and a defect region in which the linear protrusion is not arranged in a part of the longitudinal direction in which the linear protrusion extends, and the linear protrusion has the end E near the defect region.

12. The separator according to claim 11, wherein the defect regions are arranged on both sides in the longitudinal direction of the arrangement region, the line-shaped protrusions have ends E near the defect regions on both sides in the longitudinal direction of the main portion, and the ratio of the total length LE of the ends E to the length L0 of the line-shaped protrusions: LE / L0 is 0.2 or more.

13. The separator according to claim 12, wherein the LE / L0 is 0.4 or greater.

14. The separator according to any one of claims 9 to 12, wherein the spacer includes a plurality of linear protrusions, and at least half of the total number of the plurality of linear protrusions have the end portion E.

15. The separator according to claim 14, wherein 4 / 5 or more of the total number of the plurality of line-shaped protrusions have the end portion E.

Images