One example of a flexible battery includes an electrochemical cell layer and a wrapping layer that wraps the electrochemical cell layer. The flexible battery further includes an energy absorbing layer. The energy absorbing layer is located between the wrapping layer and upper and lower surfaces, which are opposite to each other, of the electrochemical cell layer. The energy absorbing layer includes a plurality of supporting parts that protrude outward from the upper or lower surface of the electrochemical cell layer. The plurality of supporting parts are mainly made of a foam material or rubber. For the energy absorbing layer, a lower-modulus buffering layer or an empty part may be further disposed between the electrochemical cell layer and the wrapping layer, to complement a wavy surface of the supporting part to form a flat surface, so as to meet diversified requirements of a wearable device.