Technical Papers and Presentations

Abstract: A 3.2V/10Ah LFP aluminum-laminated batteries are chosen as the target of the present study. A three-dimensional thermal simulation model is established based on finite element theory and proceeding from the internal heat generation of the battery[13]. The study illustrates a three-dimensional relationship among the total internal heat generation rate of the battery, the discharge rate of the battery, and the depth of discharge. The interior chemical reversible heat of the battery is manifested by the endothermic process when DOD is smaller than 0.7 and by the exothermic process when DOD is larger than 0.7. The irreversible heat takes an increasingly dominant role with the increase of discharge rate; under the condition of high-rate discharge, batteries with a single-side tab distribution are generally found to have a non-uniform cell temperature distribution, while those with a double-side tab distribution have improved cell temperature distributions[10-12]. Widening the tabs can also greatly reduce the maximum temperature of the cell.

Introduction Lithium-ion batteries feature high working voltages, high energy densities, long life spans and low self-discharge rates, and thus have been widely applied in high-power applications. Battery design can be guided by adopting the currently fast-developing computer numerical simulation technology. By combining the related theory of heat transfer and establishing the electro-thermal model of batteries, numerical simulation can shorten the design cycle, by gaining time and cutting costs. Compared with the traditional experimental verification, numerical simulation has been shown to be unparalleled in its superiority as a battery thermal design technique. The 3.2V/10Ah LFP aluminum-laminated batteries are chosen as the target of the present study. By establishing a three-dimensional thermal simulation model based on finite element theory and proceeding from the heat generation inside the battery, the study discusses in detail the evolution of different heat generation mechanisms during the batteries’ dissipation process, and probes into the cell temperature distributions of batteries with different tab designs.

Results and discussion Conclusion A three-dimensional thermal simulation model based on finite element theory is established using 3.2 V/10 Ah LFP as the research object. The thermal behavior of the discharge process can be effectively simulated by coupling the dynamic changes of the battery temperature, internal resistance, and voltage temperature coefficient.

Acknowledgment Supported by funds from the National Natural Science Foundation of China (No. 51204211), the China Postdoctoral Science Foundation (No. 2012M521543) and the Open-End Fund for the Valuable and Precision Instruments of Central South University.