Non-aqueous electrolyte battery and method of manufacturing the same
A non-aqueous electrolyte secondary battery includes a positive electrode having a positive electrode active material layer containing a positive electrode active material, a negative electrode having a negative electrode active material, a separator interposed between the positive electrode and the negative electrode, an electrode assembly comprising the positive electrode, the negative electrode, and the separator, and a non-aqueous electrolyte impregnated in the electrode assembly. The positive electrode active material contains at least cobalt or manganese. The positive electrode has an end-of-charge potential of 4.40 V versus the potential of a lithium reference electrode. The positive electrode active material layer is superficially coated with a polymer layer composed of a polymer having a partially cross-linked structure and a molecular weight of 800,000 or greater.
1. A non-aqueous electrolyte secondary battery comprising:
a positive electrode having a positive electrode active material layer comprising a positive electrode active material containing at least cobalt or manganese, the positive electrode having an end-of-charge potential of 4.40 V or higher versus the potential of a lithium reference electrode;
a polymer layer formed on a surface of the positive electrode active material layer, the polymer layer composed of a polymer having a partially cross-linked structure and a molecular weight of 800,000 or greater;
a negative electrode having a negative electrode active material;
a separator interposed between the positive electrode and the negative electrode;
an electrode assembly comprising the positive electrode, the negative electrode, and the separator; and
a non-aqueous electrolyte impregnated in the electrode assembly.
2. The non-aqueous electrolyte battery according to claim 1 , wherein the polymer layer has a mass per unit area of the positive electrode active material layer of 3.3×10 −4 g/cm 2 or less.
3. The non-aqueous electrolyte battery according to claim 2 , wherein the product of separator thickness x (μm) and separator porosity y (%) is 1500 (μm·%) or less.
4. The non-aqueous electrolyte battery according to claim 3 , wherein the product of x and y is 800 (μm·%) or less.
5. The non-aqueous electrolyte battery according to claim 4 , wherein the positive electrode active material layer has a filling density of 3.40 g/cc or greater.
6. The non-aqueous electrolyte battery according to claim 5 , wherein the positive electrode active material contains at least lithium cobalt oxide containing aluminum or magnesium in a solid solution, and zirconia is attached on the surface of the lithium cobalt oxide.
7. The non-aqueous electrolyte battery according to claim 6 , wherein the positive electrode has an end-of-charge potential of 4.45 V or higher versus the potential of a lithium reference electrode.
8. The non-aqueous electrolyte battery according to claim 5 , wherein the positive electrode has an end-of-charge potential of 4.45 V or higher versus the potential of a lithium reference electrode.
9. The non-aqueous electrolyte battery according to claim 4 , wherein the positive electrode active material contains at least lithium cobalt oxide containing aluminum or magnesium in a solid solution, and zirconia is attached on the surface of the lithium cobalt oxide.
10. The non-aqueous electrolyte battery according to claim 4 , wherein the positive electrode has an end-of-charge potential of 4.45 V or higher versus the potential of a lithium reference electrode.
11. The non-aqueous electrolyte battery according to claim 2 , wherein the positive electrode active material layer has a filling density of 3.40 g/cc or greater.
12. The non-aqueous electrolyte battery according to claim 2 , wherein the positive electrode active material contains at least lithium cobalt oxide containing aluminum or magnesium in a solid solution, and zirconia is attached on the surface of the lithium cobalt oxide.
13. The non-aqueous electrolyte battery according to claim 2 , wherein the positive electrode has an end-of-charge potential of 4.45 V or higher versus the potential of a lithium reference electrode.
14. The non-aqueous electrolyte battery according to claim 1 , wherein the product of separator thickness x (μm) and separator porosity y (%) is 1500 (μm·%) or less.
15. The non-aqueous electrolyte battery according to claim 14 , wherein the product of x and y is 800 (μm·%) or less.
16. The non-aqueous electrolyte battery according to claim 15 , wherein the positive electrode active material layer has a filling density of 3.40 g/cc or greater.
17. The non-aqueous electrolyte battery according to claim 1 , wherein the positive electrode active material layer has a filling density of 3.40 g/cc or greater.
18. The non-aqueous electrolyte battery according to claim 1 , wherein the positive electrode active material contains at least lithium cobalt oxide containing aluminum or magnesium in a solid solution, and zirconia is attached on the surface of the lithium cobalt oxide.
19. The non-aqueous electrolyte battery according to claim 1 , wherein the positive electrode has an end-of-charge potential of 4.45 V or higher versus the potential of a lithium reference electrode.