CHARGING SYSTEM

A charging system includes at least one first charging device and at least one second charging device that are cascaded. The first charging device includes at least one first accommodation portion for mounting a first energy storage device and a connecting port for connecting the second charging device or the first charging device. The second charging device includes at least one second accommodation portion for mounting a second energy storage device and a connecting port for connecting the first charging device or the second charging device. The first accommodation portion and the second accommodation portion have different shapes or dimensions.