Patent ID: 8530067

Claim:
A battery, comprising: a spirally wound body including a spirally wound laminate of a cathode and an anode with an electrolyte in between, wherein, the anode includes (a) an anode current collector having a plurality of layers, including an inner current collector layer and an outer current collector layer, (b) an outer anode active material layer disposed on an outer winding surface of the outer current collector layer of the anode current collector, and (c) an inner anode active material layer disposed on an inner winding surface of the inner current collector layer of the anode current collector, the outer anode active material layer and the inner anode active material layer both include an amorphous compound or a microcrystalline compound of silicon or tin having a particle diameter in a range of 0.1 μm to 35 μm, a capacity ratio per unit area of the inner anode active material layer to the outer anode active material layer in at least one region is within a range of 0.6 to 0.8 inclusive, and a sectional surface of the spirally wound body has one of an elliptical shape and a shape including a straight line and a curved line, and a ratio of a longest diameter to a shortest diameter of the sectional surface of the spirally wound body with respect to the center of the spirally wound body is within a range of 1 to 3 inclusive.