Experimental study on temperature distribution and electro-thermal characteristics of prismatic lithium iron phosphate batteries

Understanding the heat distribution within batteries and the relationship of electrochemical performance and operating conditions is essential for the design of battery thermal management systems. In this paper, a 280 Ah lithium iron phosphate batteries commonly used in new energy vehicles and energy storage systems are selected as the research object. An experimental test bench is established to investigate three typical discharge rates (0.25P, 0.33P, and 0.5P) under five ambient temperatures (6 ℃ , 16 ℃ , 25 ℃ , 35 ℃ and 45 ℃), in order to analyze the temperature distribution and electro-thermal characteristics of the batteries. The results show that ambient temperature has a more significant effect on the maximum battery temperature, while the charge/discharge rate has a stronger effect on surface temperature difference and temperature rise. Battery performance is more adversely affected under and high-rate operation at low temperatures and high-rate operation at high temperatures. The maximum surface temperature difference at 0.5P exceeds the recommended limit of 5 ℃ under all ambient conditions, while it also exceeds 5 ℃ at 0.33P under 6 ℃ and 16 ℃ . At low ambient temperatures, the battery surface temperature distribution exhibits a “hot bottom and cold top” pattern, whereas at high temperatures the distribution reverses. Based on preliminary monitoring point screening, the locations of hot and cold spots on the battery surface are identified. The findings provide useful guidance for optimizing battery thermal management system design and enhancing system efficiency.