The invention relates to a novel
liquid injection, infiltration and pre-charging process for
lithium ion batteries. The process comprises the following steps: (S1) carrying out vacuum operation on a
lithium ion battery before
liquid injection, injecting a predetermined amount of
electrolyte, and filling a proper amount of film forming additive gas into the battery after injection of
electrolyte is finished; (S2) employing the manner of cyclical fluctuation negative pressure infiltration, wherein, fluctuation of negative pressure is expressed with a waveform function instead of a simple first grade linear function; (S3) carrying out formation under the conditions of changing negative pressure and changing temperature, wherein, the negative pressure and temperature both increase gradiently with time, a charging current is not constant and varies in a manner of small
gradient increase. The invention enables a predetermined amount of
electrolyte to be rapidly absorbed by
anode and
cathode materials and diaphragms of the battery, and
absorption time is short while full absorption is realized, thereby improving the
utilization rate of the electrolyte and shortening time for
liquid injection; addition of a proper amount of film forming additive gas is beneficial for the formation of SEI membranes and enables inreversible
capacity loss of the battery in initial charge to be reduced; the method of pre-charging brought forward in the invention enables uniform and stable SEI membranes to form on the surface of electrodes, thereby improving safety performance and electrochemical performance of
lithium ion batteries; the process is simple and is easy to control,
investment cost for equipment used in the process is low, and the process is easy to realize.