Lithium ion battery manufacturing method and lithium ion battery

The embodiment of the invention relates to the technical field of batteries, and discloses a lithium ion battery manufacturing method and a lithium ion battery. The manufacturing method of the lithium ion battery comprises the following steps: injecting an electrolyte into a shell of the lithium ion battery; and after the electrolyte is injected into the shell of the lithium ion battery, performing formation on the lithium ion battery. According to the manufacturing method, heat generated in the formation process of the lithium ion battery is utilized to promote infiltration of the electrolyte on the pole piece. The heat generated by formation can promote the diffusion of components such as lithium ions in the electrolyte in the lithium ion battery shell, so that the pole piece is well soaked; in addition, heat generated by formation can promote escape of local trace gas between the pole piece and the adjacent structure, so that the heat generated in the formation process can accelerate infiltration of the el