Thermoelectric coupling model construction of 21,700 cylindrical ternary lithium batteries under wide temperature range environment

The electrochemical properties, heat production properties and safety of lithium-ion batteries are significantly affected by the ambient temperature. In this paper, a combination of experimental and simulation methods is used to reveal the differences of the battery thermoelectric coupling characteristics under wide temperature range environment (from − 20 ℃ to 40 ℃) by taking 21,700 cylindrical ternary lithium batteries as examples. We design the battery model characterization method, carry out the battery charging and discharging characteristics experiments under different ambient temperatures, extract the respective modeling key parameters, reveal the differences of parameters under different temperatures, and construct the battery thermoelectric coupling model under wide temperature range environment. Simultaneously, we utilize the model constructed above to conduct simulations and experimentally verify battery thermal performance. By comparing experimental data acquired through infrared thermography and K-type thermocouples with simulation outcomes, we find the error to be below 5%. Unlike the homogeneous heat source model, the model constructed in this paper can simulate the uneven temperature field. In comparison to both equivalent circuit models and electrochemical-thermal coupling models, it involves fewer computations. It considers both the precision of simulating battery thermal performance and practicality for market-oriented popularity, which lays the foundation for research and market-oriented popularity related to battery thermal management design under wide temperature range environment.