The invention discloses a supercapacitor which comprises a capacitor barrel shell, an electrolyte, a cell and end covers. The electrolyte and the cell are arranged in the capacitor barrel shell, and the end covers are arranged at the two ends of the capacitor barrel shell. A liquid injecting hole is formed in one end cover, and sealing grooves are arranged in the end covers. First sealing rings are arranged in the sealing grooves, and locking parts matched with the end covers and sealing parts matched with the first sealing rings are arranged on the capacitor barrel shell. The supercapacitor has the advantages that the locking part matched with the end covers are arranged on the capacitor barrel shell, the end covers are clamped on the capacitor shell, the end covers are provided with the sealing grooves and the first sealing rings, the sealing parts matched with the first sealing rings are arranged on the capacitor barrel shell, and sealing between the capacitor barrel shell and the end covers is achieved. The above structure is arranged, a traditional welding connection mode is replaced, the production efficiency is improved, and production cost is lowered.