Energy-storage device, electrical apparatus, and winding method

An electrical apparatus, comprising at least one energy-storage device configured to power the electrical apparatus, wherein

• each of the at least one energy-storage device comprises an electrode and a separator, wherein the electrode and the separator are stacked and wound to form a cell, the electrode is connected with a tab at an end of the electrode in a width direction of the electrode, wherein the tab comprises a first tab and at least one second tab, and wherein the first tab is positioned adjacent to an end of the electrode in a length direction of the electrode, and the first tab defines a U-shaped notch for identification;
• the first tab has a first end away from the electrode, the U-shaped notch extends from the first end toward the electrode, the first tab has a round that protrudes outwards and is connected between an internal side wall of the U-shaped notch and the first end, wherein the first end of the first tab has a surface that is farther away from the electrode than the U-shaped notch in the width direction of the electrode, the internal side wall has an end that is farther away from the electrode than the rest of the internal side wall in the width direction of the electrode, and the round is connected between the surface of the first end of the first tab and the end of the internal side wall of the U-shaped notch;
• a ratio of a radius of the round to a width of the U-shaped notch is greater than 0.15 and less than 0.2, and a ratio of the radius of the round to a depth of the U-shaped notch is greater than 0.05 and less than 0.15;
• in the width direction of the electrode, the first tab has a width less than a width of each of the at least one second tab, a ratio of the width of the first tab to the width of each of the at least one second tab is greater than 0.5 and less than 1;
• and
• the energy-storage device further comprises a housing and a cover, wherein the cell is received in the housing, the cover is provided with an adaptor piece, and the tab is stacked and welded with the adaptor piece;
• the tab has a tab root at one side of the tab close to the electrode, and a distance that the adaptor piece extends beyond an end of each of the at least one second tab away from the tab root in the width direction is greater than or equal to 2 mm.