Experimental investigation on the charge-discharge performance of the commercial lithium-ion batteries

The lithium ion battery has been widely applied in the fields of electric vehicles and electronic products due to its advantages of high power density, long lifespan and low self-discharging, etc. In this study, two lithium ion batteries are adopted to explore the effects of different thermal conditions on battery's performance. One of thermal conditions makes battery close to adiabatic condition similar to the thermal condition of battery pack without any thermal management system. Another thermal condition is constant temperature condition employed to simulate the thermal condition of battery pack with thermal management system. The experimental results show that (i) next chargeable capacities of these batteries are dependent on the previous dischargeable capacities for all thermal conditions; (ii) dischargeable capacities of these batteries markedly decrease with the increase of the discharge rates under 20^°C constant temperature condition; (iii) dischargeable capacities are independent on discharge rates under close to adiabatic condition because the obvious battery temperature rise can offset the adverse effects of higher discharge rates on battery's performance. Although higher battery temperature is conductive to weaken or eliminate the adverse effects of higher discharge rates, excessively high temperature can also accelerate battery aging and easily cause battery thermal runaway, which indicates that it is necessary for battery pack with thermal management system to control thermal conditions of batteries.