Battery thermal management system with heat pipe considering battery aging effect

Battery aging in electric vehicles affects both thermal characteristics and electrochemical performance of batteries. In this paper, a more realistic and generic model combining electrochemical reactions, capacity decay and heat transfer is developed for the design of battery thermal management system (BTMS) to ensure efficient and durable operation of batteries. Multiphysics behaviors of the battery pack with heat pipe-BTMS (HP-BTMS) and micro heat pipe-BTMS (MHP-BTMS) under different working cycles are analyzed and compared. It is found that HP-BTMS and MHP-BTMS can provide good thermal management for batteries for several working cycles only. Both HP-BTMS and MHP-BTMS fail to provide effective cooling to the batteries after 1250 cycles, due to the higher heat generation of the aged battery due to solid electrolyte interphase (SEI) formation. As MHP-BTMS always shows a better cooling performance than that of HP-BTMS, optimizations are made for MHP-BTMS in terms of the heat transfer performance. The results show that MHP-BTMS with X direction MHP, non-equidistant arrangements and cold plates can effectively control the battery temperature even after 1250 cycles and prevent the SEI formation and capacity decay.