Numerical study of positive temperature coefficient heating on the lithium-ion battery at low temperature

The performance of lithium-ion batteries may decline at cold temperatures, leading to reduced capacity and electrolyte freezing. To ensure proper operation of energy storage stations in cold regions, heating methods must be designed to maintain batteries at 283.15 K while limiting the temperature difference to less than 5 K. Theoretical analysis and simulation of a battery heating method were conducted using a 22 Ah lithium iron phosphate battery as the research object at 253.15 K. A heating method was designed using Positive Temperature Coefficient (PTC) aluminum plate heaters. Results showed that under the condition of an ambient temperature of 253.15 K and a discharge rate of 1 C, five 120 W PTCs could increase the peak temperature to 283.46 K at 1000 s. The heating method was further optimized by changing the PTC number (2, 3, and 4) and size (corresponding to 120%, 100%, 80%, and 60% of the lithium-ion battery dimensions), and it was found that by using 3 PTC heating plates with 80% size, the maximum temperature could be increased to 289.85 K and the average temperature difference was 4.82 K at 1000 s, meeting the needs of battery operation. The heating method was shown to be effective in rapidly increasing the battery temperature at lower ambient temperatures (243.15, 253.15, and 263.15 K), increasing the rate of temperature increase by 32.4% at 243.15 vs 253.15 K and 45.2% at 263.15 K.