Clear Answer First: A battery cell is the smallest electrochemical unit that stores energy, a battery module is a group of cells electrically and mechanically integrated together, and a battery pack is a complete power system that includes modules (or cells), protection. Clear Answer First: A battery cell is the smallest electrochemical unit that stores energy, a battery module is a group of cells electrically and mechanically integrated together, and a battery pack is a complete power system that includes modules (or cells), protection. In modern energy storage systems, batteries are structured into three key components: cells, modules, and packs. Each level of this structure plays a crucial role in delivering the performance, safety, and reliability demanded by various applications, including electric vehicles, renewable energy. A battery cell is the basic unit of a battery, serving as a small container that stores and releases electrical energy through chemical reactions. It consists of electrodes (anode and cathode) separated by an electrolyte and enclosed in a casing. It comes with key parts: the cells, a cooling system, a Battery Management System (BMS), and connectors.