Patent ID: 8563164
Filing Date: 2013-10-22
Classification: H01M,Y02E,Y02P

Abstract:
1. A cylindrical type alkaline storage battery comprising: an electrode assembly contained in a cylindrical container having electrical conductivity, the electrode assembly being a roll obtained by rolling up a positive electrode plate, a negative electrode plate and a separator together, wherein, provided that a maximum diameter of the container in millimeters is Dmax and that a number of turns of the positive electrode plate is N, a relationship N≧[0.5×Dmax−2.65] is fulfilled (where “[ ]” represents Gauss' notation), the electrode assembly is rolled up using a core and has a hollow corresponding to the core at a center thereof, a value obtained by dividing a cross-sectional area of the electrode assembly except for the hollow, as viewed in cross section of the battery, by a value obtained by subtracting a cross-sectional area of the hollow in the electrode assembly from a cross-sectional area of an interior of the container is greater than or equal to 95% and is smaller than or equal to 100%, and provided that a circumferential position of a roll starting end of the positive electrode plate is a reference position, an angle θ measured from a circumferential position of a roll terminating end of the positive electrode plate to the reference position along the positive electrode plate is in a range of from 180° to 270°, both inclusive, the positive electrode plate has an electrode body extending between the roll starting end and the roll terminating end; and a small-thickness portion that is located in the roll terminating end and is smaller in thickness than the electrode body, wherein the battery further has an insulating boundary protective member that is interposed between the separator covering a radially outward surface of the positive electrode plate and the positive electrode plate; the boundary protective member covers a boundary between the small-thickness portion and the electrode body; and the boundary exists only in the radially outward surface of the positive electrode plate; and the surface opposite to the boundary in the positive electrode plate is flat, wherein roundness of the cross-sectional form of the electrode assembly after activation process is higher than that of the cross-sectional form of the electrode assembly before the activation process, and the cross-sectional area of the hollow after the activation process is smaller than that of the hollow before the activation process.