Computational Fluid Dynamics Modeling of Pack-Level Battery Thermal Management Systems in Electric Vehicles
Listed in
This article is not in any list yet, why not save it to one of your lists.Abstract
Electric vehicles (EVs) are considered as a primary choice for environmentally friendly transportation. Among the current available battery types, lithium-ion (Li-ion) batteries are the most favored by car companies. Li-ion batteries are rechargeable with high energy storage density and tend to generate excess heat during operation. In EVs, the batteries are arranged in the battery pack (BP), which has a small layout space and difficulty in dissipating heat. Therefore, in EVs, the battery thermal management systems (BTMSs) are critical to manage heat to ensure safety and performance, particularly under higher operating temperatures and longer discharge conditions. To solve this problem, in this article, the thermal analysis models of a 3-battery-cell BP were created, including natural air cooling without a BTMS, natural air cooling with water cooling hybrid BTMS, and forced air cooling plus water cooling composite BTMS. The thermal performances of the pack-level BPs were simulated and analyzed based on computational fluid dynamics (CFD). A variety of boundary conditions and working parameters, such as ambient temperature, inlet coolant flowrate and initial temperature, discharge rate, air flowrate and initial temperature, were considered. The results show that without a BTMS, the temperature in the BP rises rapidly and continuously to above the recommended operating temperature range (ROTR) under the discharge rate of 2C or above. With a hybrid BTMS, the temperature in BP is slightly above the ROTR. While with a composite BTMS, the temperature is within the ROTR. In addition, lowering the initial coolant temperature or air temperature can effectively decrease the temperatures in BP. Finally, the thermal performances of the different battery cells in the BP with different cooling systems and at the different positions of the BP were compared and analyzed. The present work may contribute to the design of BTMSs in the EV industry.