Pole piece and battery cell

The invention provides a pole piece and a battery cell, the pole piece comprises a current collector and an active substance layer arranged on the surface of at least one side of the current collector, a first groove and a second groove are formed in the side, away from the current collector, of the active substance layer, and the depth of the first groove and the depth of the second groove are both smaller than the thickness of the active substance layer; the current collector is provided with a first side and a second side which are opposite along the first direction and a third side and a fourth side which are opposite along the second direction, the first grooves extend along the first direction formed by the first side pointing to the second side, the second grooves extend along the second direction formed by the third side and the fourth side, and the number of the second grooves is larger than that of the first grooves. The number of the first grooves in the first direction is relatively small, and the