Current collector, electrode and lithium ion battery

The utility model provides a current collector, a pole piece and a lithium ion battery, aiming at overcoming the phenomena of short circuit and even thermal runaway of the battery caused by direct contact between the current collector and the current collector or an active material when the insulating capacity of a diaphragm in the battery is invalid and the pole piece falls off in an abnormal condition in the prior art. The current collector is provided with a first surface and a second surface, the first surface and the second surface are oppositely arranged on the two sides of the current collector in the thickness direction, a plurality of pits are formed in at least one of the first surface and the second surface, and the area of the pits in the first surface and/or the second surface accounts for 30%-95% of the area of the first surface and/or the second surface. According to the current collector provided by the invention, the first surface contains the pits, when the pole piece falls off, materials in the grooves are difficult to fall off due to different stress, and even if the materials fall off due to stress, the pole piece after material falling can only leak out a small part of foil, namely, the foil exposing area is 1t; lt; therefore, the amount of exposed aluminum is controlled to a certain extent, the contact area and the short circuit degree between the current collectors in the battery cell and the active material or between the current collectors are reduced, and the safety of the battery cell is improved.