Lithium-ion battery

Abstract

A lithium secondary battery may include a battery case, an electrode assembly and electrolyte housed inside the battery case, and a cap plate configured to seal the battery case, the battery case may include a first end and a second end facing the first end, and the lithium secondary battery has an internal pressure of 21 kgf / cm². 2 In the above configuration, at least a portion of the electrode assembly is configured to be discharged through the first end of the battery can, and after a portion of the electrode assembly has been discharged through the first end of the battery can, the distance from the end of the electrode assembly furthest from the battery can to the second end of the battery can is 1.25 times or more the distance between the first and second ends of the battery can.

Claims

1. A lithium secondary battery comprising a battery casing, an electrode assembly and electrolyte housed inside the battery casing, and a cap plate configured to seal the battery casing, The battery can includes a first end and a second end facing the first end, The lithium secondary battery has an internal pressure of 21 kgf / cm² in the battery case. ２ In the above case, at least a portion of the electrode assembly is configured to be discharged through the first end of the battery can. A lithium secondary battery in which, after a portion of the electrode assembly is discharged through the first end of the battery can, the distance from the end of the electrode assembly furthest from the battery can to the second end of the battery can is 1.25 times or more the distance between the first end and the second end of the battery can.

2. The aforementioned lithium secondary battery is a) Before the lithium secondary battery undergoes thermal runaway, or before the lithium secondary battery undergoes thermal runaway; or b) Before the side of the battery can bursts, or before the side of the battery can bursts, The lithium secondary battery according to claim 1, wherein a portion of the electrode assembly is configured to be discharged through the first end of the battery can.

3. The first end of the battery can includes a vent portion, or The lithium secondary battery according to claim 1, wherein the cap plate is fixed to the first end of the battery can, and the cap plate includes a vent portion.

4. The lithium secondary battery according to claim 3, wherein a part of the electrode assembly is configured to be discharged through the first end of the battery can after damage to the structure that fixes the cap plate to the first end of the battery can, or after the vent portion is broken.

5. The aforementioned cap plate includes a vent portion, The vent section has an internal pressure of 21 kgf / cm². ２ A lithium secondary battery according to claim 1, configured to rupture in the above cases.

6. The vent section has an internal pressure of 25 kgf / cm². ２ Over 29 kgf / cm² ２ A lithium secondary battery according to claim 5, configured to rupture if the value is less than [a certain value].

7. The lithium secondary battery according to claim 1, comprising a first current collector plate provided between the first end of the battery can and the electrode assembly.

8. The lithium secondary battery according to claim 7, wherein the first current collector plate includes a battery can coupling portion having a tapered structure.

9. The lithium secondary battery according to claim 7, wherein the flame discharge area is 30% to 50% of the total opening area of ​​the first end of the battery can.

10. The lithium secondary battery according to claim 1, wherein the ratio of the diameter to the height of the lithium secondary battery is 0.4 or more.

11. The lithium secondary battery according to claim 1, wherein the lithium secondary battery is a 46110-cell, 4875-cell, 48110-cell, 4880-cell, 4680-cell, or 4695-cell battery.

12. The lithium secondary battery according to claim 1, wherein the electrode assembly is cylindrical.

13. The lithium secondary battery according to claim 1, wherein the thickness of the side surface of the battery can is 0.1 mm to 0.4 mm.

14. The electrode assembly is a jelly roll type electrode assembly in which a positive electrode plate and a negative electrode plate are wound in one direction together with a separator membrane interposed between the positive electrode plate and the negative electrode plate, and after a portion of the electrode assembly is discharged through the first end of the battery can, the electrode assembly has a helical structure, as described in claim 1.

15. The lithium secondary battery according to claim 14, wherein a sealing tape containing polypropylene or polyimide is attached to the outermost end of the electrode assembly.

16. The positive electrode plate and the negative electrode plate each include a blank area where no active material layer is formed. The lithium secondary battery according to claim 14, wherein at least a portion of the blank portion of the positive electrode plate or the negative electrode plate is formed as an electrode tab.

17. The blank portion of the positive electrode plate and the blank portion of the negative electrode plate are formed on one edge of the positive electrode plate and the negative electrode plate, respectively, along the direction in which the electrode assembly is wound. The first current collector plate is coupled to the blank portion of the positive electrode plate, and the second current collector plate is coupled to the blank portion of the negative electrode plate. The lithium secondary battery according to claim 16, wherein the first current collector plate and the second current collector plate are each connected to electrode terminals.

18. The plain portions of the positive electrode plate and the negative electrode plate are processed into a plurality of segmented pieces that can be independently bent. The lithium secondary battery according to claim 17, wherein at least a portion of the plurality of independently bendable segmental pieces is bent toward the winding center of the electrode assembly.

19. At least some of the independently bendable segments overlap at the upper end or lower end of the electrode assembly. The lithium secondary battery according to claim 18, wherein the first current collector plate and the second current collector plate are bonded to a plurality of overlapping segmented pieces.

20. A battery pack comprising a lithium secondary battery according to any one of claims 1 to 19.

21. An electric vehicle comprising the battery pack of claim 20 as a power source.

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