Winding-type cell

Abstract

The invention provides a winding-type cell which comprises a first pole piece, a second pole piece, an isolating membrane, a first pole tab and a second pole tab, wherein the first pole piece is provided with a first current collector and a first active substance layer coating the first current collector; the second pole piece is provided with a second current collector and a second active substance layer coating the second current collector; a second winding initial section of the second pole piece is provided with a blank second current collector; the isolating membrane separates the first pole piece from the second pole piece; the first pole tab is electrically connected with the first current collector; and the second pole tab is fixed in the blank second current collector. A first winding initial section of the first pole piece comprises a main body part and a fold-back part, wherein the main body part is positioned outside the second winding initial section, and a length of the main body part is greater than that of the second winding initial section; the fold-back part is positioned inside the main body part; the fold-back part is not overlapped with the second pole tab in a thickness direction; and the fold-back part is provided with a blank first current collector. The position of the first pole tab exceeds the end part of the second winding initial section; and a third winding initial section of the isolating membrane is folded back inwards and is positioned between the first pole tab and the second pole tab.

Description

technical field [0001] The invention relates to the field of batteries, in particular to a winding battery core. Background technique [0002] With the development of commercialization of lithium-ion batteries, the market has higher and higher requirements for their energy density. refer to figure 1 , the blank positive current collector 111 (Al foil, aluminum foil) of the head of the conventional winding battery is shorter than the negative current collector 211 (Cu foil, copper foil), and the inside of the winding battery needs two layers of empty rolls Separator 3 ( figure 1 The part of the separator surrounded by the virtual frame is the separator of the empty roll), which not only causes the waste of the separator 3, but also makes the separator 3 overlap with the positive electrode tab 4 and the negative electrode tab 5 in the thickness direction T, thus increasing the battery capacity. The thickness of the battery reduces the energy density of the battery. Conten...

AI Technical Summary

Problems solved by technology

refer to figure 1 , the blank positive current collector 111 (Al foil, aluminum foil) of the head of the conventional winding battery is shorter than the negative current collector 211 (Cu foil, copper foil), and the inside of the winding battery needs two layers of empty rolls Separator 3 ( figure 1 The part of the separator surrounded by the virtual frame is the separator of the empty roll), which not only causes the waste of the separator 3, but also makes the separator 3 overlap with the positive electrode tab 4 and the negative electrode tab 5 in the thickness direction T, thus increasing the battery capacity. The thickness of the cell reduces the energy density of the cell

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