Lithium-ion battery

Abstract

The present invention relates to a lithium secondary battery including an electrode assembly in which a positive electrode plate, a negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate are wound in one direction, a battery can in which the electrode assembly is housed, and a sealing body that seals an open end of the battery can, wherein the positive electrode plate includes a positive electrode active material layer, and the positive electrode active material layer includes a positive electrode active material powder formed of a single particle, a pseudo-single particle, or a combination thereof, and flake graphite.

Claims

1. A secondary battery comprising an electrode assembly in which a positive electrode plate, a negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate are wound in one direction, a battery case in which the electrode assembly is housed, and a seal that seals the open end of the battery case, The positive electrode plate includes a positive electrode active material layer, The positive electrode active material layer comprises a positive electrode active material including single particles, pseudo-single particles, or a combination thereof, flake graphite, and carbon nanotubes. The aforementioned flake-like graphite is contained in the positive electrode active material layer at an amount of 0.05% to 5% by weight. The positive electrode active material includes a lithium nickel-based oxide represented by the following [Chemical Formula 1], in a lithium secondary battery: [Chemical formula 1] Li a Ni b Co c M 1 d M 2 e O 2 In the above chemical formula 1, M1 is a combination of Mn and Al, and M2 is one or more selected from the group consisting of Zr, W, Y, Ba, Ca, Ti, Mg, Ta, and Nb, with 0.8 ≤ a ≤ 1.2, 0.83 ≤ b < 1, 0 < c < 0.17, 0 < d < 0.17, and 0 ≤ e ≤ 0.

1.

2. The lithium secondary battery according to claim 1, wherein the porosity of the positive electrode active material layer is 15% to 23%.

3. The loading amount of the positive electrode active material layer is 570 mg / 25 cm². ２ The lithium secondary battery according to claim 1.

4. The D of the positive electrode active material ｍｉｎ The lithium secondary battery according to claim 1, wherein the particle size is 1.0 μm or larger.

5. The positive electrode active material is D ５０ The lithium secondary battery according to claim 1, wherein the diameter is 5 μm or less.

6. The positive electrode active material is D ｍａｘ The lithium secondary battery according to claim 1, wherein the diameter is 12 μm to 17 μm.

7. The lithium secondary battery according to claim 1, wherein the positive electrode active material has a particle size distribution (PSD) of 3 or less, represented by the following formula (1). Equation (1): Particle size distribution (PSD) = (D ｍａｘ -D ｍｉｎ ) / D ５０

8. The lithium secondary battery according to claim 1, wherein the positive electrode active material has a unimodal particle size distribution showing a single peak in a volume cumulative particle size distribution graph.

9. The lithium secondary battery according to claim 1, wherein the single particle, pseudo-single particle, or combination thereof is included in an amount of 95% to 100% by weight relative to the total weight of the positive electrode active material contained in the positive electrode plate.

10. The lithium secondary battery according to claim 1, wherein the positive electrode active material contains a lithium nickel-based oxide containing 80 mol% or more of Ni with respect to the total number of moles of transition metals.

11. The lithium secondary battery according to claim 1, wherein in the chemical formula 1, 0.90 ≤ b < 1.

12. The lithium secondary battery according to claim 1, wherein the positive electrode active material has an average primary particle size of 0.5 μm to 5 μm.

13. The lithium secondary battery according to claim 1, wherein the negative electrode plate includes a silicon-based negative electrode active material.

14. The lithium secondary battery according to claim 1, wherein the negative electrode plate comprises a silicon-based negative electrode active material and a carbon-based negative electrode active material.

15. The lithium secondary battery according to claim 14, wherein the silicon-based anode active material and the carbon-based anode active material are contained in a weight ratio of 1:99 to 20:

80.

16. The lithium secondary battery according to claim 1, wherein the lithium secondary battery is a cylindrical battery having a form factor ratio of 0.4 or more.

17. The lithium secondary battery according to claim 16, wherein the cylindrical battery is a 46110 cell, a 4875 cell, a 48110 cell, a 4880 cell, or a 4680 cell.

18. 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 1, wherein at least a portion of the blank portion of the positive electrode plate or the negative electrode plate defines an electrode tab.

19. The blank portion of the positive electrode plate and the blank portion of the negative electrode plate are each formed at the end of one side of the positive electrode plate and the negative electrode plate, along the direction in which the electrode assembly is wound. A current collector plate is attached to the blank portion of the positive electrode plate and the blank portion of the negative electrode plate, The lithium secondary battery according to claim 18, wherein the current collection plate is connected to the electrode terminals.

20. The blank portion of the positive electrode plate and the blank portion of the negative electrode plate are processed into a plurality of segmented pieces that can be independently folded. The lithium secondary battery according to claim 19, wherein at least a portion of the plurality of segmented pieces is bent toward the winding center of the electrode assembly.

21. At least some of the bent segments overlap on the upper and lower ends of the electrode assembly. The lithium secondary battery according to claim 20, wherein the current collection plate is bonded to the overlapping plurality of segmented pieces.

22. The lithium secondary battery according to claim 18, wherein an insulating layer is further formed on the positive electrode plate in a direction parallel to the winding direction, covering a portion of the positive electrode active material layer and a portion of the blank portion.

23. The lithium secondary battery according to claim 1, wherein the flake-like graphite is contained in the positive electrode active material layer in an amount of 0.05% to 3% by weight.

24. The lithium secondary battery according to claim 1, wherein the flake-like graphite has an average particle size of 2 μm to 10 μm.

25. A battery pack comprising a lithium secondary battery according to any one of claims 1 to 24.

26. An automobile comprising the battery pack described in claim 25.

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