Patent ID: 7960050

Claim:
A method for manufacturing a secondary battery, comprising the steps of: (a) preparing a positive electrode plate and a negative electrode plate each including a current collector and a mixture layer containing an active material and formed on a surface of the current collector; (b) placing, on each of upper and lower faces of the electrode plates, a roller whose surface is provided with a plurality of projections, and rotating and moving the rollers with the rollers pressed against each of both faces of the electrode plate, thereby forming a plurality of trenches in a surface of the mixture layer at each of the both faces of the electrode plate at a time; (c) winding the positive electrode plate and the negative electrode plate with a separator interposed therebetween, thereby forming an electrode group; and (d) housing the electrode group in a battery case together with an electrolyte; wherein in step (b), the projections on the surface of the rollers have curvature portions at tips of the projections, only the projections are pressed against the surface of the electrode plate so that the trenches are formed in the surface of the mixture layer, and the trenches are continuously formed at a pitch of 200 μm or less along a longitudinal direction of the electrode plate in the surface of the mixture layer at each of the both faces of the electrode plate.