Negative pole piece, lithium ion battery and electric device

The invention discloses a negative pole piece, a battery and an electric device. The negative pole piece is applied to the lithium ion battery and comprises a negative current collector and a negative active layer arranged on one side of the negative current collector, wherein the surface of the negative electrode active layer, which is far away from the negative electrode current collector, is provided with a plurality of grooves which are arranged at intervals, the width W of each groove is 0.5-1 [mu] m, the distance T between two adjacent grooves meets the condition that W is greater than or equal to T * X and less than or equal to 1.5 * T * X, and X is the elongation rate of the negative electrode active layer in the direction vertical to the grooves. By adopting the mode, the expansion of the negative electrode active layers on the two adjacent sides can be fully absorbed by the grooves, so that the negative electrode plate does not expand in the charging process, the failure problem of the negative electrode plate in the recycling process is avoided, and the service life of the negative electrode plate is prolonged.