This note applies the Boundary Science Structural Reduction methodology to batteries as an example of energy conversion and storage. Batteries convert chemical energy into electrical energy through reversible electrochemical reactions, with losses primarily through internal resistance, side reactions, and degradation over cycles. It is the ninth paper in Group 7 (Energy Conversion and Engineered Work) of Volume III of the Structural Atlas. The case study identifies dominant structural primitives and explores how organized energy-conversion pathways are maintained in electrochemical storage systems