Experimental results of quasi-optimal charging current patterns to reduce the internal heat generation of the lithium-ion battery

Battery powered trains should finish the rapid charge in the scheduled stopping time. It is important to reduce the internal heat generation of the lithium-ion battery during the period of rapid charge, to prevent overheat of the battery. A quasi-optimal current pattern was derived by the developed simple search algorithm to reduce the internal heat generation. This algorithm requires less calculation cost, and is based on a third order equivalent circuit model of a test battery. Experimental results, under some ambient temperatures: 15°C, 25°C, 35°C, demonstrated that the quasi-optimal current pattern reduced 0.3-0.5% of the internal heat generation, and 0.4-0.9% of the temperature rise compared to those of the constant current pattern.