Multiple design approaches can be implemented to produce low impedance, power capable batteries. The core necessity is to offer sufficient energy for the mission, while ensuring that rate, heat generation, and internal chemical, mechanical, and thermal stresses are managed. Total energy can be increased through the parallelization of cells and/or batteries, but often other conditions exist with respect to power delivery and current sharing, which must be considered from a total system perspective. This paper discusses the approaches that can be used to build high-energy batteries with high power capability, their general advantages and disadvantages, and then describes active research being performed to characterize the current sharing phenomena associated with highly paralleled cells operating in high power applications.