Engineering battery packs for safety and reliability

Typically, packs consist of more than 100 components, generating 50-204 kilowatt-hours at around 300 volts.

- Dr Yashodhan Pramod Gokhale VP-Battery Technology JSW Energy

Battery technologies have evolved from early lead-acid cells used in storage to nickel-cadmium, nickel-metal hydride and polymer batteries. This has today culminated in lithium phosphate and sodium-ion chemistries that dominate modern applications. In a Battery Energy Storage System (BESS), the battery pack is the most critical component supported by advanced cooling and safety systems. Earlier, a 20-foot container could deliver 2-3.5 MWh capacity, but technology is advancing toward compact five-megawatt-hour energy boxes. Achieving this requires integrating both an HVAC system for the container and a dedicated liquid cooling loop, often water-glycol-based, for the battery packs. Effective thermal management, along with multiple sensors, ensures safe operation and reliable performance. At the core lies the Battery Management System (BMS), which monitors cells, manages charging and discharging and safeguards against faults. The BMS communicates seamlessly with the broader Energy Management System (EMS), which ensures efficiency, safety and longevity of grid-scale storage assets.

Inside the battery pack