Temperature distribution of lithium ion battery module with inconsistent cells under pulsed heating method

Low temperature dilemma of lithium ion batteries (LIBs) is the critical restriction for electric vehicles (EVs) and LIB energy storage. As an effective internal heating strategy, the pulsed heating method has well-known advantages in heating rate and durability on cells. However, the detailed temperature distribution of the module under pulsed heating still lacks systematical study. This work carries pulsed experiments and simulations for the LIB module and studies the temperature distribution and uniformity under various pulsed parameters, ambient temperature, heat preservation and inconsistent conditions of the state of charge (SOC) and resistance. The results show that higher pulsed amplitude and lower ambient temperature will increase the heating rate and temperature difference. The resistance inconsistency will dramatically deteriorate temperature difference while the SOC change of certain cell has a negligible impact. Specifically, the temperature difference will increase 6 degrees C if the resistance of the peripheral cell is 2.5 times of others. For practical application in EVs, the maximum temperature difference can be controlled within 8.7 degrees C in a heating process from -20 degrees C to 5 degrees C in 300 s, and the change of the maximum temperature difference is controlled within 2 degrees C when the fluctuation range of certain cell SOC or resistance is 50% around the standard value. These indicate pulsed heating of LIB module or pack with wonderful temperature uniformity and therefore promising for long-time employment.

Automated summary

This study investigates the temperature distribution and uniformity of a LIB module under pulsed heating. It finds that higher pulsed amplitude and lower ambient temperature lead to increased heating rate and temperature difference. Inconsistent resistance dramatically worsens the temperature difference, while SOC change has a negligible impact. For practical application, the maximum temperature difference can be controlled within a certain range during the heating process.