An electrochemical apparatus includes a housing, an electrode assembly disposed inside the housing, a first tab group, and a first adapting piece electrically connected to the first tab group and extending out from the housing. The electrode assembly is configured to be a winding structure including a first electrode plate. The first tab group includes M first tabs connected to the first electrode plate. A thickness direction of the electrode assembly is defined as a first direction. In the first direction, the electrode assembly includes N layers of the first electrode plate, N being greater than M. The M first tabs are each connected to the first electrode plate. A plane passing through a winding center axis of the electrode assembly and perpendicular to the first direction is defined as a winding center plane. The M first tabs are disposed on two sides of the winding center plane.

An electrochemical apparatus includes a housing, an electrode assembly disposed inside the housing, a first tab group, and a first adapting piece electrically connected to the first tab group and extending out from the housing. The electrode assembly is configured to be a winding structure including a first electrode plate. The first tab group includes M first tabs connected to the first electrode plate. A thickness direction of the electrode assembly is defined as a first direction. In the first direction, the electrode assembly includes N layers of the first electrode plate, N being greater than M. The M first tabs are each connected to the first electrode plate. A plane passing through a winding center axis of the electrode assembly and perpendicular to the first direction is defined as a winding center plane. The M first tabs are disposed on two sides of the winding center plane.

A battery pack includes: a cover plate, a cell module, a first resin layer, a battery pack housing, and at least one first monitoring member. The cell module is accommodated inside the battery pack housing and fastened by the first resin layer, the cover plate is fastened to the battery pack housing, the cell module includes a plurality of cells stacked in a first direction. Each cell includes an electrode assembly, a cell housing configured to accommodate the electrode assembly, and a tab electrically connected to the electrode assembly. The cell housing includes a sealing portion, and the tab extends out of the cell housing from the sealing portion in a second direction. One of the at least one first monitoring member is disposed between sealing portions of the adjacent cells. The first monitoring member is connected to the cell module and monitor temperature of the tab of the cell.

A battery pack includes: a cover plate, a cell module, a first resin layer, a battery pack housing, and at least one first monitoring member. The cell module is accommodated inside the battery pack housing and fastened by the first resin layer, the cover plate is fastened to the battery pack housing, the cell module includes a plurality of cells stacked in a first direction. Each cell includes an electrode assembly, a cell housing configured to accommodate the electrode assembly, and a tab electrically connected to the electrode assembly. The cell housing includes a sealing portion, and the tab extends out of the cell housing from the sealing portion in a second direction. One of the at least one first monitoring member is disposed between sealing portions of the adjacent cells. The first monitoring member is connected to the cell module and monitor temperature of the tab of the cell.

A secondary battery includes: an electrode assembly including a negative electrode tab at a first end and a positive electrode tab at a second end; a case including a pair of first side portions facing each of a pair of long side portions of the electrode assembly, and a pair of second side portions facing each of a pair of short side portions of the electrode assembly, the case being open in directions of the negative electrode tab and the positive electrode tab; and a retainer between at least one of the second side portions and the electrode assembly and including a concave-convex structure.

A secondary battery includes: an electrode assembly including a negative electrode tab at a first end and a positive electrode tab at a second end; a case including a pair of first side portions facing each of a pair of long side portions of the electrode assembly, and a pair of second side portions facing each of a pair of short side portions of the electrode assembly, the case being open in directions of the negative electrode tab and the positive electrode tab; and a retainer between at least one of the second side portions and the electrode assembly and including a concave-convex structure.

A battery cell is provided. The battery cell includes a tab, an electrode terminal, an adapter for electrical connection between the electrode terminal and the tab. The adapter includes a first connecting portion for electrical connection with the electrode terminal; a second connecting portion for electrical connection with the tab; a third connecting portion for connecting the first connecting portion and the second connecting portion; and a bending portion, the third connecting portion is connected with the first connecting portion by the bending portion and the third connecting portion is connected with the second connecting portion by the bending portion; the third connecting portion includes a reinforcing portion, and the reinforcing portion is located at the connection of the third connecting portion and the bending portion; the minimum distance L from an edge of the reinforcing portion to a center line of the bending portion satisfies: R<L<(R+2).

Provided are a secondary battery and a battery pack including the secondary battery. A sealing plate has a positive electrode terminal attachment hole. A positive electrode terminal penetrates the positive electrode terminal attachment hole. An external conductive member is connected to a portion of the positive electrode terminal located on the battery outer side with respect to the sealing plate. The conduction path between a positive electrode plate and the positive electrode terminal is provided with a current interrupting mechanism. A first insulating member made of resin is disposed between the sealing plate and the positive electrode terminal. A second insulating member having higher thermal resistance than the first insulating member is disposed between the external conductive member and the sealing plate.

Provided are a secondary battery and a battery pack including the secondary battery. A sealing plate has a positive electrode terminal attachment hole. A positive electrode terminal penetrates the positive electrode terminal attachment hole. An external conductive member is connected to a portion of the positive electrode terminal located on the battery outer side with respect to the sealing plate. The conduction path between a positive electrode plate and the positive electrode terminal is provided with a current interrupting mechanism. A first insulating member made of resin is disposed between the sealing plate and the positive electrode terminal. A second insulating member having higher thermal resistance than the first insulating member is disposed between the external conductive member and the sealing plate.

The embodiments of the application provides an end cover assembly, a battery cell, a battery module and a device, the end cover assembly is used for the battery cell, the end cover assembly includes an end cover; an electrode terminal disposed on the end cover; an insulating member for insulating the electrode terminal and the end cover and disposed to surround the electrode terminal; wherein the insulating member abuts the electrode terminal, at least one of the insulating member and the electrode terminal is provided with a stress relief groove, the stress relief groove is configured to absorb stress generated by the electrode terminal's abutting the insulating member.