Electronic device, charging method, and charging system for charging batteries in series

This application provides an electronic device, a charging method, and a charging system for charging two batteries connected in series. The charging integrated circuit controls, based on a target voltage corresponding to each preset period, a charging mode for charging the two batteries. As a charging process is prolonged, the voltages of the two batteries gradually increase, and the target voltage obtained varies with each period. A turning point of switching from constant current charging to constant voltage charging is determined based on the target voltage, and the target voltage is related to the minimum voltage value of the two batteries in each preset period. The charging mode is adjusted based on the target voltage corresponding to each preset period instead of a fixed target voltage. This reduces a probability of battery overcharging and improves battery charging reliability.