One example includes a battery that includes a stack of at least one substantially planar anode and at least one substantially planar cathode, wherein the stack defines a contoured exterior, and a battery housing enclosing the stack, the battery housing defining a battery housing exterior, wherein the contoured exterior of the stack is shaped to conform to a contoured interior of the battery housing that approximately conforms to the battery housing exterior, the battery produced by the process of modeling, using fluid dynamics, an exterior of a biocompatible housing and shaping the battery housing to conform to at least some of the exterior of the biocompatible housing.