The invention belongs to the field of batteries, and specifically relates to a
lithium ion battery. The
lithium ion battery provided by the invention comprises an electrolytic solution, a
current collector and a battery box, as well as positive and negative pole columns which penetrate through the wall of a battery box from inside to outside and are used for leading current out, and the positive and negative pole columns comprise an inner pole column positioned on the inner cavity of the battery box and at a wall thickness region and an outer pole column extending out of the battery box; and the
current collector is convexly provided with a pole ear in an extending manner, the pole ear and the inner pole column are fixedly connected and arranged, and a sealed
insulation layer covers the part of the pole ear, the inner pole column and a joint between the pole ear and the inner pole column, which at least contacts with the electrolytic solution. The
lithium ion battery provided by the invention has the advantages that the structure is simple, an
electroplating phenomenon is effectively buffered, the charge-
discharge efficiency of the
lithium battery is improved, the oscillation of a contacting
ohm internal resistance of the battery is effectively restrained, and the use consistency of the battery is improved; and the
cycling life of the battery is greatly prolonged, the high manufacturing cost of the
lithium ion battery at present is effectively reduced, and finally, the
lithium ion battery provides a guarantee for manufacturers to rapidly expand the market.