Lithium-ion laptop battery test and energy recycling.

Before recycling used lithium-ion laptop batteries, testing and sorting work is needed through charge and discharge tests. For current lithium-ion battery charge and discharge tests, the battery is discharged through a resistor. Thus, the energy in the process is all dissipated. In this paper, an energy-recycling battery test system model is introduced. In the system, a Li-ion 18650 battery can be charged at a constant current mode and a constant voltage mode and discharged at a constant current mode, which are realized by PWM-controlled DC-DC converters. The modes are automatically switched through a controller. In the discharging process, energy is transferred from the under-test battery to a storage battery, which can also serve as a charging source instead of the DC power supply to recycle the energy. The system is simulated using Matlab Simulink. Its test accuracy and energy-transferring efficiency is considerable. According to the simulation results, the system can save about 50% energy overall in one charge and discharge cycle.