Electrode piece, electrode assembly, secondary battery and electric device

The invention provides a pole piece, an electrode assembly, a secondary battery and an electric device, an active material layer used for forming a concave surface of a bending layer is concavely provided with a buffer space, and the buffer space is controlled not to penetrate through a current collector. In the winding process of the pole piece with the design, active substance redundancy occurring when the active substance layer is bent into a concave surface is at least partially replaced by the buffer space, so that when the active substance layer on the pole piece is bent at the corner area, buffer is formed in the buffer space, and the phenomenon that the pole piece is broken due to mutual extrusion of the active substance redundancy is avoided; therefore, the stability of the performance of the secondary battery is effectively improved.