Secondary battery and pole piece thereof

Abstract

The invention provides a secondary battery and a pole piece thereof. The pole piece comprises a current collector, an active material layer and a first protective layer. The current collector comprises an insulating layer and a conductive layer arranged on the surface of the insulating layer, the conductive layer is provided with a main body portion and a protruding portion connected with the mainbody portion, and the surface of the main body portion away from the insulating layer is covered by the active material layer, and the surface of the protruding portion away from the insulating layeris not covered by the active material layer. The first protective layer is arranged on one side of the protruding portion away from the insulating layer. The pole piece further comprises a conductivestructure, the conductive structure comprises a connecting portion and a first extending portion, the connecting portion is fixed to the protruding portion, the first extending portion is connected to the connecting portion and exceeds one end of the protruding portion away from the main body portion; and along the height direction, the first protective layer is located one side of the connectingportion close to the active material layer. The secondary battery provided by the invention comprises the above pole piece.

Description

technical field [0001] The invention relates to the field of batteries, in particular to a secondary battery and pole pieces thereof. Background technique [0002] A pole piece of a secondary battery generally includes a current collector and an active material layer coated on the surface of the current collector. In order to improve the safety performance of the secondary battery, some pole pieces 1 select a current collector 11 with a multilayer structure, referring to figure 1 and figure 2 , the current collector 11 includes an insulating layer 111 and a conductive layer 112 disposed on the surface of the insulating layer 111 , and the active material layer 12 is coated on the surface of the conductive layer 112 . The conductive layer 112 includes a main body 1121 covered by the active material layer 12 and a protrusion 1122 protruding outside the active material layer 12. The protrusion 1122 is used to electrically connect with the electrode terminals of the secondary...

AI Technical Summary

Problems solved by technology

However, during rolling, the roller R directly exerts an active force on the active material layer 12, and since the protrusion 1122 of the conductive layer 112 is not coated with the active material layer 12, the roller R does not exert an active force on the protrusion 1122; refer to figure 2 Since the elastic modulus of the insulating layer 111 is smaller than that of the conductive layer 112, when subjected to the force of the roller R, the deformation of the insulating layer 111 is greater than that of the conductive layer 112, resulting in the main body 1121 and the protrusion The insulating layer 111 at the junction of the part 1122 is bulged and deformed; when the insulating layer 111 is bulged and deformed, the protruding part 1122 is also bulged and deformed. The overcurrent capability of part 1122

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