CN217334140U

CN217334140U - Electrode body and lithium battery including the same

Info

Publication number: CN217334140U
Application number: CN202220749915.2U
Authority: CN
Inventors: 张磊; 王晓明; 徐强; 杨浩田; 巩义涛
Original assignee: Jiangsu Zhuogao New Material Technology Co Ltd
Current assignee: Jiangsu Zhuogao New Material Technology Co Ltd
Priority date: 2022-03-29
Filing date: 2022-03-29
Publication date: 2022-08-30
Anticipated expiration: 2032-03-29

Abstract

The utility model relates to the technical field of lithium batteries, in particular to an electrode body and a lithium battery comprising the same, which comprises a negative electrode, wherein the negative electrode comprises a negative current collector and a negative active material layer arranged on the negative current collector; the positive electrode comprises a positive current collector and a positive active material layer arranged on the positive current collector, the lengths of the positive current collector and the negative current collector are equal, and the positive active material layer is smaller than the negative active material layer; and a separator between the positive electrode and the negative electrode to separate the positive electrode and the negative electrode. The utility model discloses an electrode body and lithium cell that contains this electrode body can simplify positive negative pole overlap alignment degree requirement, and the dry electric core of good making, and its positive and negative electrode is difficult for removing, the battery preparation of being convenient for.

Description

Electrode body and lithium battery including the same

Technical Field

The utility model relates to a lithium cell technical field especially relates to an electrode body and lithium cell that contains this electrode body.

Background

The lithium ion battery is formed by winding or overlapping basic unit structures, wherein the basic unit structures are a positive electrode/a diaphragm/a negative electrode. The positive electrode and the negative electrode are places where electrochemical reaction occurs, and current generated by the electrochemical reaction is collected and led out through current collectors in the positive electrode and the negative electrode; the diaphragm is responsible for separating positive pole and negative pole, avoids positive negative pole to take place to contact and appears the short circuit.

During charging, lithium ions are extracted from the positive electrode active material, enter the electrolyte, move to the negative electrode end, and finally are inserted into the negative electrode active material. In this process, if there is not a sufficient amount of negative active material to accommodate lithium ions, the lithium ions are electrochemically reacted and deposited on the surface of the negative electrode in the form of metallic lithium dendrites. The lithium dendrites pierce the separator, causing short circuit between the positive and negative electrodes, and causing combustion and explosion of the lithium battery. The total lithium ion capacity of the negative electrode active material is therefore greater than that of the positive electrode material. At the edge portion of the positive electrode 20 '/separator 30'/negative electrode 10 ', it is necessary to design the size of the separator 30' to the size of the negative electrode 10 'to the size of the positive electrode 20' in order to prevent the formation of lithium dendrites, as shown in fig. 1. The dimension of the negative electrode exceeding the positive electrode becomes overhang.

The design of a negative electrode overlap is adopted in the existing structure, in the manufacturing process of the battery, the positions of a positive electrode and a negative electrode need to be accurately aligned, the accuracy of the negative electrode overlap is ensured, and the manufactured dry battery core needs to be very careful when moving, so that the movement of the positive electrode and the negative electrode is avoided, and the requirement of the overlap is exceeded.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is: the technical problems that the position of a positive electrode and the position of a negative electrode are not convenient to accurately position and a manufactured dry battery core is not convenient to move due to the adoption of a negative electrode overlap design in the prior art are solved. The utility model provides an electrode body and lithium cell that contains this electrode body can simplify positive negative pole overlap alignment degree requirement, and the dry electric core of good preparation, and the difficult removal of its positive negative pole, the battery preparation of being convenient for. The utility model provides a technical scheme that its technical problem adopted is: an electrode body, comprising:

a negative electrode including a negative electrode current collector and a negative electrode active material layer disposed on the negative electrode current collector;

a positive electrode including a positive current collector and a positive active material layer disposed on the positive current collector, the positive current collector and the negative current collector being equal in length, the positive active material layer being smaller than the negative active material layer;

a separator between the positive electrode and the negative electrode to separate the positive electrode and the negative electrode.

Further, in order to facilitate winding and positioning, the positive active material layer is located in the middle of the positive current collector, and two ends of the positive current collector in the length direction of the positive current collector are exposed.

Furthermore, in order to prevent the anode current collector from moving easily after being wound, the two exposed ends of the anode current collector are respectively coated with an insulating layer.

Further, the insulating layer material is any one of alumina, boehmite, magnesium hydroxide, or barium titanate.

The utility model also provides a lithium cell, including the aforesaid electrode body.

The beneficial effects of the utility model are that, the utility model discloses an electrode body sets up unanimously through the length with negative current collector and anodal mass flow body, when positive electrode, diaphragm and negative electrode one end are aligned and are convoluteed, the other end of positive electrode and negative electrode aligns equally, the location of being convenient for convolute, and difficult removal is less than negative active material layer through setting up anodal active material layer, and lithium ion takes off from anodal active material and inlays out the entering electrolyte, removes to the negative pole end, imbeds great negative active material layer at last, effectively avoids the production of metal lithium dendrite.

Drawings

The present invention will be further explained with reference to the drawings and examples.

Fig. 1 is a design of a negative overlap of a prior art electrode body;

fig. 2 is a schematic structural view of the electrode body of the present invention;

fig. 3 is a schematic structural view of the electrode body of the present invention with an insulating layer added;

fig. 4 is a schematic winding diagram of the design of the negative electrode overlap of a prior art electrode body;

fig. 5 is a schematic view of the electrode body winding structure of the present invention.

In the figure:

the prior art is as follows: 10', a negative electrode; 20', a positive electrode; 30', a membrane;

the utility model discloses: 10. a negative electrode; 11. a negative current collector; 12. a negative electrode active material layer; 20. a positive electrode; 21. a positive current collector; 22. a positive electrode active material layer; 30. a diaphragm; 40. an insulating layer.

Detailed Description

The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic drawings and illustrate the basic structure of the present invention only in a schematic manner, and thus show only the components related to the present invention.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like, indicate the orientation or positional relationship indicated based on the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore, should not be construed as limiting the present invention. Furthermore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless otherwise specified.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may include, for example, a fixed connection, a detachable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in fig. 2, an electrode body includes: a negative electrode 10, a positive electrode 20, and a separator 30, the negative electrode 10 including a negative electrode current collector 11 and a negative electrode active material layer 12 disposed on the negative electrode current collector 11; the positive electrode 20 includes a positive electrode current collector 21 and a positive electrode active material layer 22 disposed on the positive electrode current collector 21, the positive electrode current collector 21 and the negative electrode current collector 11 are equal in length, and the positive electrode active material layer 22 is smaller than the negative electrode active material layer 12; separator 30 is positioned between positive electrode 20 and negative electrode 10 to separate positive electrode 20 and negative electrode 10.

For the convenience of further location, anodal active material layer 22 is located the intermediate part of anodal mass flow body 21, and anodal mass flow body 21 exposes along its length direction's both ends, one of them implementation includes: the positive electrode active material layer 22 is arranged on the positive electrode current collector 21 by coating, the size of the positive electrode active material layer 22 is as large as that of the positive electrode current collector 21 in the coating process, and after the coating is finished, the positive electrode active materials at two ends of the positive electrode current collector 21 are removed, so that two ends of the positive electrode current collector 21 are exposed. As shown in fig. 3, the two exposed ends of the positive current collector 21 are respectively coated with an insulating layer 40, and the insulating layer 40 is made of a ceramic material such as alumina, boehmite, magnesium hydroxide, barium titanate, etc., or a polymer material such as polyethylene, polypropylene, PET, aramid, etc.

As shown in fig. 5, the electrode body of the present invention is consistent in length setting of the negative current collector 11 and the positive current collector 21, when the positive electrode 20, the separator 30 and the negative electrode 10 are aligned to one end for winding, the other end of the positive electrode 20 and the other end of the negative electrode 10 are also aligned, compared with the winding of the negative electrode overlap design in the prior art, as shown in fig. 4, the positive electrode 20 is smaller than the negative electrode 10, the two ends of the positive electrode 20 and the two ends of the negative electrode 10 are not aligned, the positioning and winding are not convenient, even after the dry cell is manufactured after the positioning and winding in the earlier stage, the moving process also easily leads to the dislocation of the positive electrode 20 and the negative electrode 10, and the present invention effectively avoids the above problems.

The utility model also provides a lithium cell, including above-mentioned electrode body.

To sum up, the utility model discloses a positive negative pole overlap alignment degree requirement can be simplified to the electrode body, is convenient for the production preparation of battery.

In light of the foregoing, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined by the scope of the claims.

Claims

1. An electrode body, characterized by comprising:

a negative electrode (10), the negative electrode (10) comprising a negative electrode current collector (11) and a negative electrode active material layer (12) disposed on the negative electrode current collector (11);

a positive electrode (20), said positive electrode (20) comprising a positive current collector (21) and a positive active material layer (22) disposed on said positive current collector (21), said positive current collector (21) and said negative current collector (11) being of equal length, said positive active material layer (22) being smaller than said negative active material layer (12);

a separator (30), the separator (30) being located between the positive electrode (20) and the negative electrode (10) to separate the positive electrode (20) and the negative electrode (10).

2. The electrode body according to claim 1, wherein the positive electrode active material layer (22) is located at a middle portion of the positive electrode current collector (21), and both ends of the positive electrode current collector (21) in a length direction thereof are exposed.

3. Electrode body according to claim 2, characterized in that the exposed ends of the positive current collector (21) are each coated with an insulating layer (40).

4. The electrode body according to claim 3, wherein the insulating layer (40) material is any one of alumina, boehmite, magnesium hydroxide, or barium titanate.

5. A lithium battery comprising the electrode body according to any one of claims 1 to 4.