The invention discloses a method for increasing the battery liquid injection speed. The method comprises the steps of slurrying, single-surface coating of a battery electrode piece and double-surface coating of the battery electrode piece, and is characterized in that after the single-surface coating of the battery electrode piece and before the double-surface coating of the battery electrode piece, a step of primary electrode piece back rolling treatment is added; before the step of rolling, a step of secondary electrode piece back rolling treatment is added. According to the method disclosed by the invention, after single-surface coating, the electrode piece is subjected to back rolling at first; after back rolling, the electrode piece is subjected to double-surface coating; therefore, air hole channels in both surfaces of the electrode piece can simultaneously face to the rolling direction to a certain extent during rolling, the electric cell liquid injection speed can be increased, and the production efficiency is improved. Before rolling, the electrode piece is subjected to back rolling again, the electrode piece at the single and double-surface coating end is adjusted to the outer end of an electrode piece roll to be rolled at first, so that the electric cell liquid injection speed can be increased more effectively, and the production efficiency is improved better.