CN219180547U

CN219180547U - Lithium battery negative plate and lithium ion battery

Info

Publication number: CN219180547U
Application number: CN202222737608.5U
Authority: CN
Inventors: 吴小超; 袁雷; 宋清; 向磊; 刘志礼; 孟延熬; 刘燕君; 赵福; 袁潮; 李维伟
Original assignee: Huizhou Kaiyuan New Energy Technology Co ltd
Current assignee: Huizhou Kaiyuan New Energy Technology Co ltd
Priority date: 2022-10-18
Filing date: 2022-10-18
Publication date: 2023-06-13
Anticipated expiration: 2032-10-18

Abstract

The utility model discloses a lithium battery negative plate and a lithium ion battery, comprising a negative plate body, a first coating and a second coating; the negative electrode sheet body comprises a high polymer material layer, a first conductive layer and a second conductive layer, wherein the high polymer material layer is positioned between the first conductive layer and the second conductive layer; the first conductive layer is provided with a first coating area, the first conductive layer is provided with a second coating area, the first coating is coated in the first coating area, and the second coating is coated in the second coating area; the electrode plate body is characterized in that an electrode lug is further arranged on the electrode plate body, the electrode lug comprises a welding section, the welding section is placed on the electrode plate body, and a plurality of fixing rivets penetrate through the welding section and the electrode plate body. The yield of the welding tab of the negative plate can reach 100%.

Description

Lithium battery negative plate and lithium ion battery

Technical Field

The utility model belongs to the field of battery negative plates, and particularly relates to a lithium battery negative plate and a lithium ion battery.

Background

The safety and energy density of lithium batteries are currently of great concern. Along with the development of the lithium ion battery towards the high energy density, the safety problem of the battery is increasingly outstanding, and the copper foil used for the negative plate is easily damaged or broken under the action of external force in the production process, so that defective products are caused; in addition, the metal copper foil layer of the finished lithium battery is easy to break after being damaged by needling and the like, and the copper foil is easy to pierce the lithium battery diaphragm after breaking, so that internal short circuit is caused to cause heating runaway, and the production qualification rate of the negative electrode plate and the safety performance of the lithium battery are urgently required to be improved.

In addition, in the processing process of welding the tab on the lithium battery negative plate, the tab is welded and fixed on the negative plate in a general ultrasonic welding mode; the defect is particularly obvious when ultrasonic welding is carried out for a long time and the welding heads are overheated to cause unstable electronic components to generate false welding, so that defective products of the negative electrode plates are caused, and especially the materials of mutually welded workpieces are different, so that the false welding problem in the production process of the negative electrode plates needs to be solved.

Disclosure of Invention

The utility model aims to provide a lithium battery negative plate and a lithium ion battery, which are used for solving the technical problems of safety of the negative plate and poor welding of the negative plate.

In order to achieve the above purpose, the specific technical scheme of the lithium battery negative plate and the lithium ion battery is as follows:

a lithium battery negative plate comprises a negative plate body, a first coating and a second coating; the negative electrode sheet body comprises a high polymer material layer, a first conductive layer and a second conductive layer, wherein the high polymer material layer is positioned between the first conductive layer and the second conductive layer; the first conductive layer is provided with a first coating area, the second conductive layer is provided with a second coating area, the first coating is coated in the first coating area, and the second coating is coated in the second coating area; the electrode plate body is characterized in that an electrode lug is further arranged on the electrode plate body, the electrode lug comprises a welding section, the welding section is placed on the electrode plate body, and a plurality of fixing rivets penetrate through the welding section and the electrode plate body to be welded and fixed.

The negative electrode sheet body is of a three-layer structure, the middle layer is a high polymer material layer, the first conductive layer and the second conductive layer can be made of metal materials, such as metal copper, and the metal materials are plated on the upper side surface and the lower side surface of the high polymer material layer to form the first conductive layer and the second conductive layer; the tab is fixed on the first conductive layer of the negative plate body through welding of a fixing rivet, and the fixing rivet penetrates through the tab, the first conductive layer, the high polymer material layer and the second conductive layer;

in the technical scheme, the negative plate body adopts the high polymer material layer, so that the toughness of the negative plate body is improved, and the problems of tearing edges, breakage, wrinkling and the like of the negative plate body in the production process can be avoided; meanwhile, the welding section of the tab is placed on the first conductive layer and is positioned outside the area of the first coating, and a fixing rivet penetrates through the welding section and the negative plate body through welding equipment, so that welding and fixing of the tab and the negative plate body are realized; in addition, the middle layer of the negative plate body adopts a high polymer material layer, and compared with the existing metal copper foil material, the thin high polymer material layers of the first conductive layer and the second conductive layer are nonconductive, so that the lithium battery can be more easily fused when an internal short circuit occurs, thereby cutting off short circuit current, reducing heat generated during short circuit and preventing thermal runaway.

According to the lithium battery negative electrode plate, the fixing rivet penetrates through the welding section of the tab and the negative electrode sheet body, the welding section of the tab is welded and fixed on the negative electrode sheet body through rivet welding, the phenomenon of tab cold welding cannot occur, the tab welding yield on the negative electrode sheet body reaches 100%, and the production yield is improved.

Further, the first conductive layer and the second conductive layer are both metal copper layers, and the high polymer material layer is a PET film.

The PET film and copper composite material used by the negative plate body is PET copper foil, and the PET copper foil has a sandwich structure of copper-PET-copper composite, wherein the PET film is taken as a base material firstly, and then a metal copper layer is deposited on the upper surface and the lower surface of the PET film by an advanced process (such as an electroplating mode) to form the PET copper foil; the PET copper foil can well prevent copper from being broken due to metal fatigue or external force, and can avoid short circuit caused by the damaged copper layer penetrating through the positive and negative electrode diaphragms, so that the safety is greatly improved; in addition, due to the addition of the PET film, the use of metal copper is reduced, and the production cost of the negative plate body is reduced.

Further, the first conductive layer has a thickness of 1 μm, the second conductive layer has a thickness of 1 μm, and the PET film has a thickness of 4 μm.

Wherein, the PET copper foil takes a PET film with the thickness of 4.0 mu m as a base film, and then copper with the thickness of 1 mu m is plated on two sides of the base film, so as to form the PET copper foil with the thickness of 6.0 mu m; the copper layer of the PET copper foil is thinner, so that the PET copper foil is easier to fuse when a local short circuit occurs, the local current is cut off, and the heat generated by the short circuit is reduced; on the other hand, the PET film of the PET copper foil is made of a polymer material, does not have conductivity, has a large resistance, and can reduce short-circuit current and improve the safety of the battery.

Further, the tab is disposed along the width direction of the negative plate, and the length of the welding section is 40% -80% of the width of the negative plate.

The welding section length of placing on the negative plate body is arranged in a ratio, so that the electrode lug can be effectively ensured to be fixed on the negative plate body through rivet welding, meanwhile, the other section length of the electrode lug outside the negative plate body can be ensured to be compounded, the electrode lug is prevented from exceeding the overlong or too short of the negative plate body, and the subsequent working procedure processing is facilitated.

Further, a lithium ion battery comprises the lithium battery negative electrode sheet described in any one of the above.

The lithium battery negative plate and the lithium ion battery have the following advantages:

1. the safety is high: the traditional copper foil is easy to break after being subjected to external force, and the broken copper foil is easy to pierce through a diaphragm, so that internal short circuit is caused to cause heating runaway; and the PET copper foil is not easy to break, and the PET film cannot be pierced even after the metal copper layer is damaged, so that the safety performance of the negative electrode plate in the use process is improved.

2. The energy density is high: compared with the traditional copper foil, the PET copper foil has less metal copper content, the PET film used in the middle layer has light overall mass, correspondingly reduces the weight of the battery, and increases the energy density of the lithium battery.

3. The cost is low: the traditional copper foil accounts for about 8% -10% of the cost of the lithium battery, and the amount of metal copper contained in the adopted PET copper foil is greatly reduced, so that the production cost is greatly reduced in the large-scale production process.

4. According to the lithium battery negative electrode plate, the fixing rivet penetrates through the tab and the PET copper foil, the tab is welded and fixed on the PET copper foil through rivet welding, the tab cold welding phenomenon cannot occur, the welding yield of the tab reaches 100%, and the production yield is improved.

Drawings

FIG. 1 is a top view of a negative electrode sheet of a lithium battery according to the present utility model;

fig. 2 is a cross-sectional view of a negative electrode sheet of a lithium battery according to the present utility model;

the figure indicates: 1. a negative electrode sheet; 101. a first conductive layer; 102. a PET film; 103. a second conductive layer; 2. a first coating; 3. a second coating; 4. a tab; 401. fixing a rivet; 402. and (5) welding the sections.

Detailed Description

In order to better understand the purpose, structure and function of the present utility model, the following describes a lithium battery negative electrode sheet and a lithium ion battery in detail with reference to the accompanying drawings.

As shown in fig. 1-2, the lithium battery negative plate comprises a negative plate body 1, a first coating 2 and a second coating 3; the negative electrode sheet body 1 comprises a high polymer material layer, a first conductive layer 101 and a second conductive layer 103, wherein the high polymer material layer is positioned between the first conductive layer 101 and the second conductive layer 103; a first coating area is arranged on the first conductive layer 101, a second coating area is arranged on the second conductive layer 103, the first coating 2 is coated in the first coating area, and the second coating 3 is coated in the second coating area; the cathode sheet body 1 is further provided with a tab 4, the tab 4 comprises a welding section 402, the welding section 402 is placed on the cathode sheet body 1, and a plurality of fixing rivets 401 penetrate through the welding section 402 and the cathode sheet body 1 to be welded and fixed.

In the above solution, the negative electrode sheet 1 has a three-layer structure, the middle layer is a polymer material layer, the first conductive layer 101 and the second conductive layer 103 may be made of a metal material, for example, metal copper, and the metal material is plated on the upper and lower surfaces of the polymer material layer to form the first conductive layer 101 and the second conductive layer 103; the tab 4 is fixed on the first conductive layer 101 of the negative plate body 1 through welding of the fixing rivet 401, and the fixing rivet 401 penetrates through the tab 4, the first conductive layer 101, the high polymer material layer and the second conductive layer 103;

in the technical scheme, the negative plate body 1 adopts the high polymer material layer, so that the toughness of the negative plate body 1 is improved, and the problems of tearing edges, breakage, wrinkling and the like of the negative plate body 1 in the production process can be avoided; meanwhile, the welding section 402 of the tab 4 is placed on the first conductive layer 101 and is located outside the area of the first coating 2, and the fixing rivet 401 passes through the welding section 402 and the negative plate body 1 through welding equipment, so that the tab 4 and the negative plate body 1 are welded and fixed; in addition, the middle layer of the negative plate body 1 adopts a polymer material layer, and compared with the existing metal copper foil material, the thin polymer material layers of the first conductive layer 101 and the second conductive layer 103 are nonconductive, so that the lithium battery can be more easily fused when an internal short circuit occurs, thereby cutting off short circuit current, reducing heat generated during short circuit and preventing thermal runaway.

In one embodiment, the first conductive layer 101 and the second conductive layer 103 are both metal copper layers, and the polymer material layer is a PET film 102.

In the above scheme, the composite material of the PET film 102 and copper used for the negative plate body 1 is a PET copper foil, which has a "sandwich" structure of "copper-PET-copper" composite, firstly, the PET film is used as a base material, and then, metal copper layers are deposited on the upper and lower surfaces of the PET film 102 in an advanced process (e.g. electroplating mode) to form the PET copper foil; the PET copper foil can well prevent copper from being broken due to metal fatigue or external force, and can avoid short circuit caused by the damaged copper layer penetrating through the positive and negative electrode diaphragms, so that the safety is greatly improved; in addition, due to the addition of the PET film, the use of metal copper is reduced, and the production cost of the negative plate body 1 is reduced.

In one embodiment, the thickness of the first conductive layer 101 is 1 μm, the thickness of the second conductive layer 103 is 1 μm, and the thickness of the PET film 102 is 4 μm.

In the above scheme, the PET copper foil takes a PET film 102 with the thickness of 4.0 μm as a base film, and then copper with the thickness of 1 μm is plated on two sides of the base film, so as to form a PET copper foil with the thickness of 6.0 μm; the copper layer of the PET copper foil is thinner, so that the PET copper foil is easier to fuse when a local short circuit occurs, the local current is cut off, and the heat generated by the short circuit is reduced; on the other hand, the PET film of the PET copper foil is made of a polymer material, does not have conductivity, has a large resistance, and can reduce short-circuit current and improve the safety of the battery.

In one embodiment, the tab 4 is disposed along the width direction of the negative electrode sheet 1, and the length of the welding section 402 is 40% -80% of the width of the negative electrode sheet 1.

In the above-mentioned scheme, place the welding section 402 length on negative pole lamellar body 1 and occupy the ratio setting, can effectually ensure that utmost point ear 4 passes through the rivet welding to be fixed on negative pole lamellar body 1, also can ensure the outer other section length of utmost point ear 4 of utmost point negative pole lamellar body 1 simultaneously, avoid the other section overlength of utmost point ear 4 or too short, promoted the quality of lithium cell negative pole piece.

One embodiment is a lithium ion battery comprising a lithium battery negative electrode sheet as described in any one of the above.

It will be understood that the utility model has been described in terms of several embodiments, and that various changes and equivalents may be made to these features and embodiments by those skilled in the art without departing from the spirit and scope of the utility model. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the utility model without departing from the essential scope thereof. Therefore, it is intended that the utility model not be limited to the particular embodiment disclosed, but that the utility model will include all embodiments falling within the scope of the appended claims.

Claims

1. The lithium battery negative plate is characterized by comprising a negative plate body (1), a first coating (2) and a second coating (3);

the negative electrode sheet body (1) comprises a high polymer material layer, a first conductive layer (101) and a second conductive layer (103), wherein the high polymer material layer is positioned between the first conductive layer (101) and the second conductive layer (103); a first coating area is arranged on the first conductive layer (101), a second coating area is arranged on the second conductive layer (103), the first coating (2) is coated in the first coating area, and the second coating (3) is coated in the second coating area;

the cathode sheet body (1) is further provided with a tab (4), the tab (4) comprises a welding section (402), the welding section (402) is placed on the cathode sheet body (1), and a plurality of fixing rivets (401) penetrate through the welding section (402) and the cathode sheet body (1) to be welded and fixed.

2. The lithium battery negative electrode sheet according to claim 1, wherein the first conductive layer (101) and the second conductive layer (103) are both metal copper layers, and the polymer material layer is a PET film (102).

3. The lithium battery negative electrode sheet according to claim 2, wherein the first conductive layer (101) has a thickness of 1 μm, the second conductive layer (103) has a thickness of 1 μm, and the PET layer has a thickness of 4 μm.

4. The lithium battery negative electrode sheet according to claim 1, wherein the tab (4) is disposed along the width direction of the negative electrode sheet body (1), and the length of the welding section (402) is 40% -80% of the width of the negative electrode sheet body (1).

5. A lithium ion battery, characterized in that the lithium ion battery comprises the lithium battery negative electrode sheet according to any one of claims 1-4.