Temperature equalization strategy in immersion flow boiling battery thermal management: Optimization of flow regime in boiling heat transfer

Abstract

Immersion flow boiling is a promising technique for battery thermal management to prevent thermal runaway of lithium-ion batteries. However, it poses challenges for maintaining battery temperature equalization due to the flow regime transformation caused by boiling heat transfer. To address the critical issue of flow regime transformation in immersion flow boiling battery thermal management, this study explores its causative factors and develops R-type of baffles to ameliorate the resultant deterioration in temperature equalization. The results reveal that the immersion flow boiling battery thermal management process consists of three heat transfer stages corresponding to different flow regimes, and that the alteration in pressure gradient induced by phase transition causes flow regime transformation and temperature unequalization. The key to optimal thermal management performance in immersion flow boiling is to avoid flow regime transformation by controlling the static pressure and ensuring the working medium uniformly distribute and direct heat exchange in the phase transition region. The use of baffles, especially R-type baffles, can enhance the heat transfer coefficient by up to three times and improve temperature equalization. This study provides insights for better application of immersion flow boiling for battery thermal management.