Using a non-aqueous electrolyte secondary battery containing lithium iron phosphate as a positive electrode active material and graphite as a negative electrode active material, a low-cost, high energy density battery is provided that exhibits good performance at high rate current and good cycle performance even at high temperature. The non-aqueous electrolyte secondary battery has a positive electrode having a positive electrode current collector and a positive electrode active material-containing layer formed on a surface of the positive electrode current collector, the positive electrode active material-containing layer containing a conductive agent and a positive electrode active material including lithium iron phosphate, a negative electrode containing a carbon material, and a non-aqueous electrolyte. The non-aqueous electrolyte contains vinylene carbonate.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of a battery according to one embodiment of the present invention; and
FIG. 2 is a cross-sectional view taken along line A-A in FIG. 1.
Claims
1. A non-aqueous electrolyte secondary battery comprising:
a positive electrode having a positive electrode current collector and a positive electrode active material-containing layer formed on a surface of the positive electrode current collector, the positive electrode active material-containing layer containing a conductive agent and a positive electrode active material including lithium iron phosphate;a negative electrode containing a carbon material; anda non-aqueous electrolyte containing vinylene carbonate and/or a derivative thereof.
2. The non-aqueous electrolyte secondary battery according to claim 1, wherein the content of the vinylene carbonate and/or a derivative thereof in the non-aqueous electrolyte is 4 mg or greater per 1 g of the lithium iron phosphate.
3. The non-aqueous electrolyte secondary battery according to claim 2, wherein the content of the vinylene carbonate and/or a derivative thereof in the non-aqueous electrolyte is 40 mg or less per 1 g of the lithium iron phosphate.
4. The non-aqueous electrolyte secondary battery according to claim 1, wherein the positive electrode active material-containing layer has a filling density of 1.7 g/cm3 or greater.
5. The non-aqueous electrolyte secondary battery according to claim 2, wherein the positive electrode active material-containing layer has a filling density of 1.7 g/cm3 or greater.
6. The non-aqueous electrolyte secondary battery according to claim 3, wherein the positive electrode active material-containing layer has a filling density of 1.7 g/cm3 or greater.
7. The non-aqueous electrolyte secondary battery according to claim 4, wherein the positive electrode active material-containing layer has a filling density of 3.15 g/cm3 or less.
8. The non-aqueous electrolyte secondary battery according to claim 5, wherein the positive electrode active material-containing layer has a filling density of 3.15 g/cm3 or less.
9. The non-aqueous electrolyte secondary battery according to claim 6, wherein the positive electrode active material-containing layer has a filling density of 3.15 g/cm3 or less.
10. The non-aqueous electrolyte secondary battery according to claim 1, wherein the lithium iron phosphate is superficially coated with carbon, and the amount of the carbon is from 0.5 mass % to 5 mass % with respect to the amount of the lithium iron phosphate.
11. The non-aqueous electrolyte secondary battery according to claim 2, wherein the lithium iron phosphate is superficially coated with carbon, and the amount of the carbon is from 0.5 mass % to 5 mass % with respect to the amount of the lithium iron phosphate.
12. The non-aqueous electrolyte secondary battery according to claim 3, wherein the lithium iron phosphate is superficially coated with carbon, and the amount of the carbon is from 0.5 mass % to 5 mass % with respect to the amount of the lithium iron phosphate.
13. The non-aqueous electrolyte secondary battery according to claim 1, wherein the lithium iron phosphate has a median particle diameter of 3.5 μm or less, as determined by a laser diffraction particle size analyzer.
14. The non-aqueous electrolyte secondary battery according to claim 2, wherein the lithium iron phosphate has a median particle diameter of 3.5 μm or less, as determined by a laser diffraction particle size analyzer.
15. The non-aqueous electrolyte secondary battery according to claim 3, wherein the lithium iron phosphate has a median particle diameter of 3.5 μm or less, as determined by a laser diffraction particle size analyzer.
16. The non-aqueous electrolyte secondary battery according to claim 1, wherein the lithium iron phosphate has a BET specific surface area of 10 m2/g or greater.
17. The non-aqueous electrolyte secondary battery according to claim 2, wherein the lithium iron phosphate has a BET specific surface area of 10 m2/g or greater.
18. The non-aqueous electrolyte secondary battery according to claim 3, wherein the lithium iron phosphate has a BET specific surface area of 10 m2/g or greater.
Patent Application
20070184352
