A battery apparatus including a battery structure and a control circuit, where the battery structure is in a filamentous shape, and the battery structure includes an energy storage unit disposed inside the battery structure and an electricity generator disposed around the energy storage unit, where the electricity generator is a solar battery, and the control circuit is configured to control whether the energy storage unit is electrically connected to the electricity generator in order to control whether electric energy generated by the electricity generator is transferred to and stored in the energy storage unit. The battery apparatus may not only generate electric energy, but also store the electric energy, and supply electricity to an electronic device conveniently.