Cover plate manufacturing method and battery top cover

A cover plate manufacturing method, comprising following steps:

• S101:
• providing a metal sheet, and punching the metal sheet to form punched holes;
• S102:
• flanging a portion of the metal sheet on a periphery of each of the punched holes to form a sidewall extending upward;
• S103:
• shaping and flattening each sidewall to enable each sidewall to reach a predetermined state;
• and
• S104:
• splitting a material of each sidewall to form a horizontal bottom wall and form cover plates with terminal holes;
• wherein the material forming an inner wall of each sidewall is extruded in a thickness direction to form the horizontal bottom wall.