Formula electric system: Thermal management design

This paper presents the thermal management analysis performed on lithium polymer cells designed for High Performance Electric Vehicle (HPEV) applications. The objective was to choose an optimum temperature range for the cells to operate at, determine the thermal response of the cells under their full spectrum of discharge capabilities, calculate the necessary convective heat transfer necessary to maintain the cells within said temperature range, then to create a thermal management solution to incorporate into a battery pack composed of 288 cells. Thermal testing and modeling on individual lithium polymer cells determined the thermal response and amount of convection cooling required for the cells over their intended duty cycles. A convective heat transfer coefficient of 50 W/m2K was determined to be sufficient to prevent the proposed cell from exceeding the optimum temperature range during its most strenuous duty cycle. The proposed design scheme utilized a fan to force air circulation up along the side of modules where each module consists of four cells connected in series. A proposed feedback control loop system allowed for active control of the battery cell's temperature resulting in an increase in efficiency and overall performance for HPEV applications.