Li-Ion Battery Thermal Characterization for Thermal Management Design

Abstract

Battery design efforts often prioritize enhancing the energy density of the active materials and their utilization. However, optimizing thermal management systems at both the cell and pack levels is also key to achieving mission-relevant battery design. Battery thermal management systems, responsible for managing the thermal profile of battery cells, are crucial for balancing the trade-offs between battery performance and lifetime. Designing such systems requires accounting for the multitude of heat sources within battery cells and packs. This paper provides a summary of heat generation characterizations observed in several commercial Li-ion battery cells using isothermal battery calorimetry. The primary focus is on assessing the impact of temperatures, C-rates, and formation cycles. Moreover, a module-level characterization demonstrated the significant additional heat generated by module interconnects. Characterizing heat signatures at each level helps inform manufacturing at the design, production, and characterization phases that might otherwise go unaccounted for at the full pack level. Further testing of a 5 kWh battery pack revealed that a considerable temperature non-uniformity may arise due to inefficient cooling arrangements. To mitigate this type of challenge, a combined thermal characterization and multi-domain modeling approach is proposed, offering a solution without the need for constructing a costly module prototype.

A Method for Assessing the Technical Condition of Traction Batteries Using the Metalog Family of Probability Distributions

“…Preheating typically occurs when starting a cold electric vehicle at low ambient temperatures [53]. Cooling is required, especially when charging the batteries quickly and with high power [54]. Appropriate temperature management of individual battery cells contributes to extending the time of their correct operation and increases the safe use of the entire electric vehicle.…”