Design of the Experimental Procedures for Analysis of Thermal and Electrical Properties of a Prismatic LiFeYPO4 Battery in a Modified Electric Car

摘要

As being the most important part in the energy supply system, the battery must be carefully monitored in order to optimize the performance and to prolong its life. The most affected parameter to the battery is the operating temperature as the higher operating temperature increase the performance but shorten the life and with lower operating temperature can ensure longer life but reduce the performance. With this, the battery thermal management system is created in order to keep the operating temperature at the suitable range. In order to achieve this, thermal behaviour in loaded condition must be analysed beforehand. A series of experimental procedures is designed for the selected lithium iron phosphate battery to determine the thermal properties such as heat capacity, heat generation, and cell temperature according to the electrical load applied. Derived thermal model of lithium ion battery was utilized for this purpose as it shows the relationship between the thermal, electrical properties and other parameters such as voltage, current and cell temperature. When the battery is applied with electrical load, the data of voltage, current, and surface cell temperature can be used to determine the thermal properties and at the same time, electrical properties such as open circuit voltage, state of charge and internal resistance are also obtained for the performance evaluation.