Abstract: A capacitor, a manufacturing method therefor, and a use thereof. The capacitor comprises a housing (10), a cell located in the housing (10), and a sealing device located at an opening of the housing (10), the sealing device is connected to the cell and comprises a post (3), and a metal circular ring (4) and an insulating member (5) are sequentially sleeved on the outer periphery of the post (3) from top to bottom; a first annular engagement surface is provided downwardly from the top on the outer peripheral surface of the post (3); a second annular engagement surface is provided downwardly from the top on the inner peripheral surface of the metal circular ring (4), and the first and second annular engagement surfaces are fitted to and engaged with each other; a groove having an outward opening is formed along the radial direction of the insulating member (5), and a cover plate (1) is arranged in the groove.