Experimental Investigation of the Collective Impact of Electric Current and Ambient Temperature on the Thermal and Electrical Parameters of Lithium Iron Phosphate Cells

Abstract

The performance of a lithium‐ion battery depends on the collective impact of discharge current and ambient temperature. Herein, three aspects of such impact are investigated. The first is the relationship between the thermal parameters. At 0 ºC ambient temperature and 1 C discharge rate, the heat generation rate initially increases to more than 50 kW m−3 and then dips by almost 20% due to a consequent rise in battery temperature. The second aspect is the relationship between the thermal and the electrical parameters. The steep rise in battery temperature at low ambient temperatures lifts up the voltage and improves the electrical performance more than expected. The third aspect is the collective impact of ambient temperature and electric current on the battery performance. At 0 °C ambient temperature, an increase in current from 1 to 1.5 C increases the temperature rise rate by more than two. This increases the battery capacity by at least 6% compared with that at a 1 C rate. The investigation results are expected to improve the understanding of the collective impact of current and ambient temperature on battery performance and provide a guideline for developing an optimized thermal management system.

Accurate Measurement of the Internal Temperature of 280 Ah Lithium-Ion Batteries by Means of Pre-Buried Thermocouples

“…Due to their small size, there are no significant temperature differences between the interior and surface of these batteries [7]. Data from surface thermal sensors on LIBs can be used to perform appropriate thermal management, which allows the temperature of the battery to be controlled within a reasonable range and extended life to be achieved [8][9][10]. Temperature accumulation and conduction problems occur at the pack and system levels, rather than at the cell level.…”