Temperature Equalisation Control Method for DC-DC Cascaded Energy Storage Systems Considering Temperature Trends

Abstract

The battery is a critical component in electrochemical energy storage systems. High temperatures can accelerate battery degradation and create safety risks, such as thermal failure. Thus, effective heat dissipation is essential to reduce the operating temperature, extend battery life and minimise thermal failure risks. Maintaining a low-temperature differential among batteries also improves system efficiency and economic performance. This study proposes a cascaded DC-DC energy storage system that maintains battery temperature equilibrium based on module temperature trends and reduces temperature differences by distributing power across individual DC-DC converters. First, this study investigates the heat dissipation technology of energy storage batteries. Second, to enhance the speed of temperature homogenisation, a temperature trend forecasting the equalisation control method is introduced, building upon the average temperature equalisation and positive half-range temperature difference equalisation strategies. Finally, an experimental verification is conducted on a cascaded energy storage system consisting of eight DC-DC converters with a rated power of 11.6 kW. The results indicate that during charging, the temperature difference among battery cells remains below 2°C, whereas during discharging, the temperature difference is maintained below 1°C. Overall, temperature equalisation control based on cell temperature trend prediction demonstrates excellent performance in terms of both equalisation speed and effectiveness.