Patent ID: 9225008
Filing Date: 2015-12-29
Classification: H01M,Y02E,Y02P,Y10T

Abstract:
1. A secondary battery, comprising a positive electrode in which a collector is coated with a positive electrode mixture layer, wherein the positive electrode mixture layer contains a positive electrode active material and a conductive material, a porosity X of the positive electrode mixture layer is 30(%)≦X, a mass ratio α of the positive electrode active material in the positive electrode mixture layer is 0.84≦α≦0.925, and a mass ratio β of the conductive material in the positive electrode mixture layer is 0.06≦β≦0.12, the positive electrode active material is made up of secondary particles resulting from aggregation of a plurality of primary particles of a lithium-transition metal oxide, the secondary particles each have a perforated hollow structure that has: a hollow section; and a through-hole that runs through the secondary particle so as to link the hollow section with an exterior, and an index Y worked out from an expression below is 30 (mL/100 g)≦Y≦89 (mL/100 g): wherein A is a DBP absorption number (mL/100 g) of the positive electrode active material, α is the mass ratio of the positive electrode active material in the positive electrode mixture layer, B is a DBP absorption number (mL/100 g) of the conductive material, and β is the mass ratio of the conductive material in the positive electrode mixture layer.