Early Detection of Secondary Battery Degradation by Infrared Technology: An Experimental Study

초록

Lithium-ion batteries, one of the most important energy storage technologies, are widely used in portable electronic devices, electric vehicles, and energy storage systems due to their high energy density and long cycle life. However, the degradation of the batteries causes many safety hazards. The degraded batteries show some different characteristics compared with fresh ones, such as temperature distribution and evolution which can be tested and recorded by infrared (IR) thermography. This study investigates the differences in temperature distribution and average temperature evolution of degraded and fresh 18,650 Li-ion batteries at various discharging and charging currents. It is apparent that the temperature rise rate of degraded batteries is much higher than that of fresh ones in the first 30 s at a discharging current of 9 A. Also, the temperature distribution begins to change from the very beginning of the discharging, changes fast, and becomes stable before the DoD of 0.5 in the degraded batteries, while in the fresh one, it changes slowly and becomes stable after reaching a DoD of 0.5. Results show that there are obvious differences in temperature distribution and average temperature evolution between degraded and fresh batteries at high currents, while the difference at low currents is inconspicuous, which might be caused by the increase in the internal resistance in degraded batteries. Altogether, these findings suggest the potential for early detection of degraded batteries through IR thermography technology during high-current discharging.

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