Liquid injection method and liquid injection device of soft package battery and battery

A liquid injection method of a soft package battery comprises the steps that the soft package battery is placed in a liquid injection groove which is filled with shear thickening liquid and provided with two movable battery fixing plates, and under pressure driving of positive pressure and negative pressure, the shear thickening liquid can be thickened to provide a completely-wrapped support for the edge sealing position of the battery. The liquid shear thickening liquid has good fluidity, can be attached to any battery, even a special-shaped battery, and has excellent matching performance and self-adaptability. The activation efficiency of the soft package battery can be remarkably improved, the production cost is reduced, the performance is improved, and the service life is prolonged. After the method is adopted for liquid injection, the activation time of the soft package battery can be remarkably shortened, the production efficiency is improved, the production cost is reduced, and meanwhile, the performan