Method for preparing lithium ion battery

The invention discloses a method for preparing lithium ion battery. the method comprises the steps of coating a positive electrode active material on the upper surface of a positive electrode current collector to make the surface comprising a coating region and an exposed region; coating a negative electrode active material on a negative electrode current collector; winding the positive electrode current collector coated with the positive electrode active material, the negative electrode current collector coated with the negative electrode active material and a separation membrane and putting into a battery shell; injecting an electrolyte solution in the battery shell and sealing the battery shell to obtain the lithium ion battery. According to the method for preparing the lithium ion battery provided by an embodiment of the invention, a coating method of the electrodes of the lithium ion battery are changed and the changed electrodes are assembled into the battery, so that activation time of the battery can be shortened and the cycle performance of the battery is improved, and the improvement of the cycle performance can prolong the service life of a new energy automobile.