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Improving the Air-Cooling Performance for Battery Packs via Electrothermal Modeling and Particle Swarm Optimization

A novel design optimization method is proposed to optimize the air passageway for an air-cooled battery pack with a 3P4S configuration (three strings in parallel and four cells in each string). This method includes the electrothermal model for the air-cooled pack and the optimization algorithm. Unlike other thermal models for battery packs, the model established in this article considers the interaction between the state of charge (SOC), current, heat generation, and temperature at the cell level and the impact of uneven cooling on the current distribution in the parallel branches at the pack level. Experiments are conducted to verify the prediction accuracy of the electrothermal model. The results show that the proposed model can accurately predict the electrical and thermal parameters under different conditions. For example, the root-mean-square error (RMSE) of temperature is less than 0.5 °C under all test conditions. As for the optimization algorithm, the particle swarm optimization (PSO) algorithm is used. In order to increase the optimization searching speed and accuracy of PSO, the inertia factor is added to the velocity formula, and the spatial neighborhood method is used. The design optimization method is used to optimize the air passageway of an air-cooling pack. It is found that the optimized pack not only has a lower maximum cell temperature and a smaller temperature variation among cells than the original pack but also has a smaller difference of branch current and a longer lifespan.