Patent ID: 6869727

Claim:
An electrochemical battery cell comprising: a cylindrical housing with an upstanding side wall having an inside diameter no greater than 14.0 mm; a first electrode comprising a first active material; a second electrode comprising a second active material and disposed within the first electrode; a separator disposed between the first and second electrodes; and an electrolyte; wherein: at least one of the first and second electrodes comprises a solid electrode body; the at least one of the first and second electrodes has a surface that defines a surface of a cavity in which the other of the first and second electrodes is disposed; the surface of the cavity comprises a plurality of radially extending lobes that form a plurality of concave and convex areas in the surface of the solid electrode body; each convex area has no radius less than 0.030 inch; and each concave area has no radius less than 0.030 inch; wherein: the first electrode comprises a solid body with a minimum radial thickness d 2 ; each lobe of the first electrode has a thickness d 1 , as measured between two points on the surface of the first electrode, each of the two points a radial distance from a longitudinal axis of the cell equal to an average of a radial distance from the longitudinal axis of the cell to an outermost internal surface of the first electrode and a radial distance from the longitudinal axis of the cell to an innermost internal surface of the first electrode; and a ratio d 1 :d 2 is are greater than 2.5:1 but not greater than 8.1:1.