Electrochemical devices and electronic devices

Abstract

The electrochemical device disclosed in the present application includes a wound battery cell and a casing for accommodating the battery cell. The battery cell includes a first pole piece, a second pole piece, and a film arranged in layers. The first pole piece includes a current collector, and the current collector It includes a first surface facing the inside of the battery core and a second surface facing away from the inside of the battery core; the tab is electrically connected to the current collector and protrudes from the current collector; the first active material layer is arranged on the first surface of the current collector; An active material layer includes a main coating and an edge coating. Along the first direction, the edge coating is located on the side of the main coating facing the tab, and is adjacent to or partially overlapped with the main coating; along the second direction , the main coating and the edge coating extend in a band shape, and the length of the edge coating is longer than that of the main coating; the electrochemical device has high energy density and good electrical performance.

Description

technical field [0001] The embodiments of the present application relate to the technical field of batteries, and in particular, to an electrochemical device and an electronic device. Background technique [0002] The electrochemical device has a battery cell and a casing for containing the battery cell. The battery cell generally includes a stacked pole piece and a diaphragm. The pole piece has a current collector and an active material layer disposed on the surface of the current collector. In the coating process for the production of electrochemical devices, such as figure 1 As shown, the active material layer 11 is set on the metal foil 12, and the area of ​​the active material layer 11 located at the edge of the metal foil 12 will expand outward due to the action of surface energy and gravity, resulting in the formation of a thinned area 13 at the edge of the pole piece. The thickness of the thinned region 13 is smaller than the thickness of the middle region 14, and t...

AI Technical Summary

Problems solved by technology

In the coating process for the production of electrochemical devices, such as figure 1 As shown, the active material layer 11 is set on the metal foil 12, and the area of ​​the active material layer 11 located at the edge of the metal foil 12 will expand outward due to the action of surface energy and gravity, resulting in the formation of a thinned area 13 at the edge of the pole piece. The thickness of the thinned region 13 is smaller than the thickness of the middle region 14, and the width of the thinned region is larger, which will cause the electrochemical device to separate lithium and reduce the energy density of the electrochemical device.

and if figure 2 As shown, due to the shrinkage of the slurry in the coating process, after the slurry is solidified to form a diaphragm, the corner 15 will be formed at the head and tail of the diaphragm. Because the corner 15 is relatively large, it will cause the electrochemical device to analyze. Lithium will also reduce the energy density of electrochemical devices, thereby affecting the performance of electrochemical devices

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