Clustering, Modelling and Thermal Analysis of a Hybrid Preheating System-based Lithium-ion Battery Module Under Subzero Environment

Abstract:

Subzero environment results in the accelerated performance degradation， lifespan shortage， lithium planting， and even some severe problems such as internal short circuit of lithium-ion battery cells. Therefore， preheating has become a critical issue for electric vehicle application in the low-temperature area. The consistency between the battery cells has a significant impact on the module performance and aging mechanism. In this paper， the clustering approach was utilized for battery cell selection. In addition， a hybrid battery thermal management system （BTMS） coupled with positive temperature coefficient （PTC） heating film and cooling plate is proposed， the heating efficiency of the proposed system at the ambient temperature （－40℃）was investigated through computational fluid dynamics （CFD） modelling and numerical calculation. The results indicate that the minimum temperature of the battery module can be heated to a state higher than 0 ℃ after 695 seconds of preheating. Besides， the temperature standard deviation of the battery module gets decreased by 5.9 ℃ compared with the pure PTC heating approach. Therefore， this proposed method efficiently heat the battery module to an operational state within a short heating interval， without much energy cost. The preheating speed reaches 3.56 ℃/min. Moreover， the thermal uniformity gets enhanced.

Key words:lithium-ion battery;clustering;preheating;positive temperature coefficient （PTC） heating;liquid coolant