WO2023046090A1

WO2023046090A1 - Double-sided adhesive tape and lithium ion battery

Info

Publication number: WO2023046090A1
Application number: PCT/CN2022/120957
Authority: WO
Inventors: 盛东辉; 徐腾飞; 彭宁
Original assignee: 珠海冠宇电池股份有限公司
Priority date: 2021-09-24
Filing date: 2022-09-23
Publication date: 2023-03-30
Also published as: CN113683974A

Abstract

The present application provides a double-sided adhesive tape and a lithium ion battery. The first aspect of the present application provides a double-sided adhesive tape, the double-sided adhesive tape comprising a first bonding layer, a base material layer and a second bonding layer which are sequentially stacked. The first bonding layer comprises one or more among organic silicon binders, epoxy binders, polyurethane binders, polyacrylic acid binders and rubber binders, and the bonding strength of the first bonding layer is greater than that of the second bonding layer. The double-sided adhesive tape provided in the present application comprises the two bonding layers, and the bonding strength of the first bonding layer is greater than that of the second bonding layer, and the double-sided adhesive tape may be effectively and accurately bonded on a surface of a light soft material by using a means of transferring an object to assist in gluing, thereby effectively solving the problems of wrinkling, poor positioning, bubbles appearing and the like in gluing.

Description

A kind of double-sided adhesive tape and lithium-ion battery

This application claims the priority of the Chinese patent application with the application number 202111123544.3 and the application title "a double-sided adhesive tape and lithium-ion battery" submitted to the China Patent Office on September 24, 2021, the entire contents of which are incorporated herein by reference. Applying.

technical field

The application relates to a double-sided adhesive tape and a lithium-ion battery, and relates to the technical field of lithium-ion batteries.

Background technique

Adhesive tape has the characteristics of light weight, environmental protection, and excellent bonding performance, so it is widely used in various scenes of life and industrial production, such as sealing, fixing, repairing, warning, etc. However, tapes have more inconvenience and limitations on some materials, such as light and soft polymer films, metal foils, gauze, etc., because these materials are relatively soft, and tapes exist due to the external force of the glue. Problems such as inaccurate positioning of the glue, wrinkling, skewing, and bubbles. Therefore, how to develop an adhesive tape suitable for light and soft materials has become a technical problem to be solved urgently by those skilled in the art.

Contents of the invention

The application provides a double-sided adhesive tape, which is suitable for bonding light and soft materials.

The present application also provides a lithium-ion battery, which includes a separator, and the above-mentioned double-sided tape is pasted on the surface of the separator, which can effectively solve the technical difficulty that a lithium-ion barrier layer cannot be provided on the separator.

The first aspect of the present application provides a double-sided adhesive tape, the double-sided adhesive tape includes a first adhesive layer, a substrate layer and a second adhesive layer stacked in sequence;

The first adhesive layer includes one or more of silicone, epoxy, polyurethane, polyacrylic, and rubber adhesives, and the adhesive strength of the first adhesive layer is greater than the The adhesive strength of the second adhesive layer.

As in the above-mentioned double-sided adhesive tape, the second adhesive layer includes one or more of silicone-based, epoxy-based, polyurethane-based, polyacrylic-based, and rubber-based adhesives.

As the above-mentioned double-sided tape, the thickness of the first bonding layer is 1-20 μm.

As in the above double-sided adhesive tape, the thickness of the second adhesive layer is 1-20 μm.

As in the above double-sided adhesive tape, the substrate layer includes one or more of PI, PP, PE, PET.

As the above-mentioned double-sided tape, the thickness of the substrate layer is 3-50 μm.

As above-mentioned double-sided adhesive tape, described double-sided adhesive tape also comprises release layer, and described release layer is arranged on the surface of described first adhesive layer away from base material layer, and described release layer is PE release film, PET One or more of release film, OPP release film, composite release film, glassine release paper, and CCK release paper.

As the above-mentioned double-sided adhesive tape, the thickness of the release layer is 3-100 μm.

The second aspect of the present application provides a lithium-ion battery. The lithium-ion battery includes a positive electrode sheet, a separator, and a negative electrode sheet. The negative electrode sheet includes a negative electrode current collector and a negative electrode active layer disposed on at least one surface of the negative electrode current collector. A negative electrode tab is provided on the surface of the negative electrode current collector;

The surface of the separator is pasted with any one of the above-mentioned double-sided tapes, and the vertical projection area of the negative tab on the separator falls within the vertical projection area of the double-sided tape on the separator.

Like the lithium-ion battery mentioned above, the first adhesive layer of the double-sided adhesive tape includes a hot-melt adhesive that is resistant to electrolytes, and the second adhesive layer includes a pressure-sensitive adhesive that is not resistant to electrolytes.

The implementation of the present application has at least the following advantages:

1. The double-sided adhesive tape provided by the application includes two layers of bonding layers, and the bonding strength of the first bonding layer is greater than that of the second bonding layer, which can be assisted by transferring objects to stick the glue. Effectively and accurately paste the double-sided tape on the surface of light and soft materials, effectively solving the problems of wrinkling, poor positioning, and bubbles.

2. The double-sided adhesive tape provided by this application can be used for pasting the diaphragm in lithium-ion batteries, which effectively solves the technical difficulty that the lithium-ion barrier layer cannot be provided on the diaphragm.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present application. Those skilled in the art can also obtain other drawings based on these drawings without any creative effort.

Fig. 1 is the structural representation of the double-sided adhesive tape provided by an embodiment of the present application;

Figure 2 is a schematic diagram of the use of double-sided adhesive tape provided by an embodiment of the present application;

Fig. 3 is the structural representation of the double-sided adhesive tape provided by another embodiment of the present application;

FIG. 4 is a schematic structural diagram of a lithium-ion battery provided by an embodiment of the present application;

Fig. 5 is a schematic diagram of the use of double-sided adhesive tape provided by an embodiment of the present application in a lithium-ion battery.

Explanation of reference signs:

1: double-sided tape;

1-1: the first bonding layer;

1-2: Substrate layer;

1-3: the second bonding layer;

1-4: release layer;

2: transfer objects;

3: Objects to be bonded;

101: positive current collector;

102: positive active layer;

200: diaphragm;

301: negative electrode collector;

302: negative electrode active layer;

400: Negative tab.

Detailed ways

In order to make the purpose, technical solutions and advantages of the application clearer, the technical solutions in the embodiments of the application will be clearly and completely described below in conjunction with the embodiments of the application. Obviously, the described embodiments are part of the implementation of the application. example, not all examples. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

In order to solve the problem of difficulty in applying glue on the surface of light and soft materials, the first aspect of the present application provides a double-sided adhesive tape, which includes a first adhesive layer, a base material layer and a second adhesive layer stacked in sequence ;

The application provides a double-sided adhesive tape, which has a double-sided adhesive layer, wherein the adhesive layer on one surface can be bonded to a transfer object, and the adhesive layer on the other surface of the double-sided tape is bonded to the object to be transferred by means of the transfer object. The surface of the bonded object, in which the object to be bonded is a light and soft material, if the direct glue is used, there will be problems such as inaccurate positioning of the glue, wrinkling, skewing, and bubbles, while the transfer object is not light and soft Such materials do not have the above-mentioned sticking problem. Specifically, Fig. 1 is a schematic structural diagram of a double-sided adhesive tape provided by an embodiment of the present application. -1, base material layer 1-2 and second adhesive layer 1-3, base material layer 1-2 is used as the matrix of double-sided adhesive tape 1, is used for supporting the first adhesive layer 1-1 and the second adhesive layer 1-3, the second adhesive layer 1-3 is used for bonding with the transferred object, which is arranged on one surface of the substrate layer 1-2, and the first adhesive layer 1-1 is used for bonding with the object to be bonded , which is arranged on the other surface of the substrate layer 1-2, the first adhesive layer 1-1 and the second adhesive layer 1-3 both include an adhesive, the difference is that the first adhesive layer 1-1 The bonding strength is greater than the bonding strength of the second bonding layer 1-3, and the first bonding layer includes one or more of silicone, epoxy, polyurethane, polyacrylic, and rubber adhesives , those skilled in the art can reasonably select the type of adhesive and ensure that the bonding strength of the first adhesive layer is greater than that of the second adhesive layer; in the above five types of adhesives, some adhesives It needs to be released under the action of external force, such as pressure-sensitive adhesive, hot-melt adhesive, etc. Therefore, the bonding strength of the first adhesive layer defined in this application is greater than that of the second adhesive layer. Adhesive strength refers to the adhesive strength of the first adhesive layer and the adhesive strength of the second adhesive layer in the final state, that is, after the bonding process is completed, for example, for some materials that can be sticky without external force For the adhesive, the bonding strength of the first bonding layer is greater than the bonding strength of the second bonding layer; or, before the external force acts, the bonding strength of the first bonding layer is smaller than the bonding strength of the second bonding layer. Bond strength, the viscosity of the adhesive in the first bonding layer is released under the action of external force, so that the bonding strength of the first bonding layer is greater than the bonding strength of the second bonding layer; or, the first bonding layer The middle adhesive does not need external force to release its viscosity. Before the external force acts, the adhesive strength of the adhesive in the second adhesive layer is greater than that of the first adhesive layer. Under the action of external force, the adhesive in the second adhesive layer The viscosity of the binder is reduced or even lost, so that the bonding strength of the first bonding layer is greater than that of the second bonding layer. The properties of the agent are determined; the double-sided adhesive tape provided by the application is used to paste the second adhesive layer with the transfer object, and with the assistance of the transfer object, the first adhesive layer is pasted on the surface of the object to be pasted, for example, as shown in Fig. 2 is a schematic diagram of the method of using the double-sided adhesive tape provided by an embodiment of the present application, as shown in Figure 2, first, the second adhesive layer 1-3 is pasted on the surface of the transfer object 2, and then the object to be bonded 3 is attached to the The surface of the first bonding layer 1-1 , since the bonding strength of the first bonding layer 1-1 is greater than the bonding strength of the second bonding layer 1-3, the bonding between the first bonding layer 1-1 and the object 3 to be bonded is more firm. Those skilled in the art can retain or peel off the second adhesive layer 1-3 according to actual needs, so as to complete the bonding requirements on the surface of the object to be bonded. The double-sided adhesive tape provided by the application comprises two layers of bonding layers, and the bonding strength of the first bonding layer is greater than the bonding strength of the second bonding layer, and can effectively, Accurately paste the tape on the surface of soft objects, effectively solving the problems of light and soft materials such as wrinkling, poor positioning, and bubbles.

The same as the selection of the type of adhesive in the first adhesive layer, the second adhesive layer also includes one or more of silicone, epoxy, polyurethane, polyacrylic, and rubber adhesives A person skilled in the art can select the type of adhesive in the first bonding layer and the second bonding layer according to conventional technical means, so that the bonding strength of the first bonding layer is greater than the bonding strength of the second bonding layer .

In a specific embodiment, the first adhesive layer includes a first pressure-sensitive adhesive, the second adhesive layer includes a second pressure-sensitive adhesive, the first pressure-sensitive adhesive and the second pressure-sensitive adhesive The sensitive adhesive releases its viscosity under the action of pressure, and after the action of pressure, the adhesive strength of the first adhesive layer is greater than that of the second adhesive layer. During use, the second adhesive layer is pasted On the surface of the transfer object, and achieve the purpose of pasting under the action of pressure, then paste the first adhesive layer on the surface of the object to be adhered, and under the action of pressure, paste the double-sided tape on the surface of the object to be pasted, and complete the double-sided tape and the object to be pasted. Bonding of pasted objects.

In another specific embodiment, the first adhesive layer includes a first pressure-sensitive adhesive and is resistant to solvents, and the second adhesive layer includes a second pressure-sensitive adhesive and is not resistant to solvents. In the process, paste the second adhesive layer on the surface of the transfer object, and achieve the purpose of pasting under the action of pressure, then paste the first adhesive layer on the surface of the object to be pasted under the action of pressure, and then apply the double-sided tape together with the The object and the transfer object are placed in the solvent, and under the solvent immersion, the bonding strength of the second bonding layer is reduced or even lost, so that the bonding strength of the first bonding layer is greater than the bonding strength of the second bonding layer, and the double bonding is completed. Adhesion of the surface tape to the object to be pasted.

In yet another specific embodiment, the first adhesive layer includes a hot-melt adhesive, the second adhesive layer includes a pressure-sensitive adhesive, and during use, the second adhesive layer is pasted on the transfer object surface, and achieve the purpose of pasting under the action of pressure, and then paste the first adhesive layer on the surface of the object to be pasted. At this time, the bonding strength of the first adhesive layer is low. The bonding strength is greater than that of the second bonding layer, and the bonding between the double-sided tape and the object to be pasted is completed.

In yet another specific embodiment, the first adhesive layer can also be a light-curable adhesive, a moisture-based adhesive, etc., and its mode of action is the same as that of the above, that is, the first adhesive layer can be made under the action of light and moisture The bonding strength of the first bonding layer is greater than that of the second bonding layer, and the bonding of the double-sided adhesive tape and the object to be pasted is completed.

Those skilled in the art can select a suitable type of adhesive, and apply the adhesive on the surface of the substrate layer to obtain an adhesive layer. The substrate layer can include conventional materials in the field. Specifically, the substrate layer includes PI , PP, PE, PET in one or more.

Further, the thickness of the substrate layer is 3-50 μm.

The adhesive coated on the surface of the substrate layer can be coated in a single layer, double layers or multiple layers, which can be selected by those skilled in the art according to actual needs. The thickness of the first adhesive layer is 1-20 μm.

Like the first adhesive layer, the second adhesive layer can also be coated with a single layer, double layer or multiple layers of adhesive, and the thickness of the second adhesive layer is 1-20 μm.

In order to facilitate the use of double-sided adhesive tape, the double-sided adhesive tape also includes a release layer, the release layer is arranged on the surface of the first adhesive layer away from the substrate layer, Figure 3 is another embodiment of the present application provides The schematic diagram of the structure of the double-sided adhesive tape, as shown in Figure 3, is provided with a release layer 1-4 on the surface of the first adhesive layer 1-1 away from the base material layer 1-2, and the release layer 1-4 does not have adhesive Bonding force, mainly used to protect the first bonding layer 1-1, the release layer is PE release film, PET release film, OPP release film, composite release film, glassine release paper, CCK release film One or more types of paper.

In use, before the first bonding layer 1-1 is bonded with the surface of the object 3 to be bonded, the release layer 1-4 is peeled off from the surface of the first bonding layer 1-1, and then bonded with the surface of the object to be bonded. Object 3 is bonded.

Further, the thickness of the release layer is 3-100 μm.

To sum up, the double-sided adhesive tape provided by the present application includes two adhesive layers, and the adhesive strength of the first adhesive layer is greater than that of the second adhesive layer, and can be assisted by transferring objects, It can effectively and accurately paste the tape on the surface of light and soft materials, effectively solving the problems of wrinkling, poor positioning, and bubbles.

Fast charging is one of the current development directions of lithium-ion batteries. Among them, the tabs are metal conductors that lead out the pole pieces from the lithium-ion batteries, and placing the tabs in the middle is one of the ways to achieve fast charging. In order to avoid the safety risk caused by lithium deposition during the battery cycle, it is usually necessary to set up a lithium ion barrier layer in the area of the vertical projection of the negative tab on the separator, that is, to stick tape on the surface of the separator. There will be problems such as glue wrinkling, position deviation, or even failure to stick on the diaphragm, and the double-sided tape provided by the application can effectively solve the above problems. Therefore, the second aspect of the application provides a lithium-ion battery. The lithium-ion battery includes a positive electrode sheet, a diaphragm, and a negative electrode sheet, the negative electrode sheet includes a negative electrode collector and a negative electrode active layer arranged on at least one surface of the negative electrode collector, and the surface of the negative electrode collector is provided with a negative electrode ear;

The present application provides a lithium-ion battery, which includes a positive electrode sheet, a negative electrode sheet, a diaphragm arranged between the negative electrode sheet and the positive electrode sheet, and a negative electrode tab. Face tape, specifically, Fig. 4 is a schematic structural diagram of a lithium-ion battery provided by an embodiment of the present application. As shown in Fig. 4, the lithium-ion battery includes a positive electrode sheet, a separator 200 and a negative electrode sheet, and the positive electrode sheet includes a positive electrode current collector 101 and a set The positive electrode active layer 102 on the surface of the positive electrode current collector, the negative electrode sheet includes the negative electrode current collector 301 and the negative electrode active layer 302 arranged on the surface of the negative electrode current collector. Negative electrode active layers 302 are arranged on both sides, and the separator 200 is located between the positive electrode sheet and the negative electrode sheet to isolate the contact between the positive electrode sheet and the negative electrode sheet. The vertical projection area on the top falls in the vertical projection area of the double-sided adhesive tape 1 on the diaphragm 200, and the double-sided adhesive tape 1 can be used as a lithium ion barrier layer to prevent the potential safety hazard caused by the negative plate lithium analysis; when the diaphragm 200 is used as the When object, can use positive plate as transfer object, for example, Fig. 5 is the schematic flow chart of double-sided adhesive tape that one embodiment of the present application provides is used in lithium-ion battery, as shown in Fig. The second adhesive layer 1-3 is pasted on the surface of the positive electrode sheet, and then the positive electrode sheet, separator, and negative electrode sheet are prepared according to the lamination process or winding process to obtain a battery cell. After the battery cell is prepared, the first adhesive in the double-sided tape 1 The junction layer 1-1 is pasted on the surface of the diaphragm 200 to complete the bonding process of the double-sided tape and the diaphragm.

When the double-sided tape includes a release layer, as in the above-mentioned lithium-ion battery preparation process, after the positive electrode sheet is prepared, the release layer needs to be peeled off from the surface of the double-sided tape, otherwise, in the later stage of lithium-ion battery preparation process, the release layer The molded layer will automatically detach from the surface of the first adhesive layer, which will affect the preparation of lithium-ion batteries. However, the exposed first adhesive layer is easy to stick to the separator during the preparation process, causing dislocation of the pasting area, which will cause serious damage to the preparation of lithium-ion batteries. Inconvenient, therefore, in order to facilitate the preparation of lithium-ion batteries and the bonding of double-sided tapes, the first adhesive layer of the double-sided tape includes a hot-melt type and electrolyte-resistant adhesive, and the second adhesive layer includes a pressure Sensitive and not resistant to electrolyte-based binders.

Hot-melt and electrolyte-resistant adhesive means that the adhesive does not have viscosity at room temperature, and releases viscosity after heat treatment, and the viscosity will not change when soaked in electrolyte. Specifically, it can be polyolefin rubber type adhesive. Binder; pressure-sensitive binder refers to the release of viscosity under pressure. After soaking in the electrolyte, it will swell and lose its viscosity, making the double-sided tape fall off from the surface of the positive electrode sheet. Specifically, it can be polyacrylic or high-swelling pressure-sensitive Rubber.

In the specific use process, first determine the area where the double-sided tape needs to be pasted on the surface of the separator, then the glue-applying mechanism rolls up the release layer and performs centralized recovery, and then pastes the second adhesive layer on the surface of the positive electrode sheet, so that the double-sided tape The pasting position corresponds to the position where the double-sided tape needs to be pasted on the surface of the separator. Since the adhesive in the first bonding layer is not viscous at this time, the double-sided tape pasted on the surface of the positive electrode sheet will not affect the rolling of the positive electrode sheet. At the same time, it can also reduce the adsorption of dust and avoid the impact on the safety performance of lithium-ion batteries; then, the positive electrode sheet, separator, and negative electrode sheet are prepared into electric cores by lamination process or winding process, and the electric cores are hot-pressed and heated. The pressing temperature is 30°C-90°C. During the hot pressing process, the viscosity of the adhesive in the first adhesive layer is released and bonded to the separator; finally, the battery is packaged and injected with electrolyte. At this time, the electrolyte makes the second The adhesive in the second adhesive layer swells and loses or greatly reduces the viscosity, while the adhesive in the first adhesive layer does not decrease, so that the double-sided adhesive tape will fall off from the surface of the positive electrode sheet and stick to the surface of the separator. Location. Those skilled in the art can select the binder according to the type of electrolyte, which is not limited in this application.

In summary, the double-sided adhesive tape provided by the present application can be used for pasting the diaphragm in lithium-ion batteries, effectively solving the technical difficulty that the lithium-ion barrier layer cannot be provided on the diaphragm.

The technical scheme provided by the application is described in detail below in conjunction with specific embodiments:

Example 1

The double-sided adhesive tape provided in this embodiment includes a second bonding layer, a substrate layer, a first bonding layer and a release layer that are stacked in sequence, wherein:

The substrate layer is a PET layer with a thickness of 12 μm;

The second adhesive layer is obtained by polymerization of 40 parts by mass of hard monomer (VAc/LMA), 60 parts by mass of soft monomer (2-EHA/BA), and 0.5 parts by mass of initiator. It is hot-melt and resistant to electrolysis Liquid adhesive;

The thickness of the second adhesive layer is 4 μm;

The first adhesive layer consists of 20 mass parts of polystyrene, 15 mass parts of polydiene, 15 mass parts of styrene-butadiene copolymer, 8 mass parts of petroleum resin, 3 mass parts of fillers and 0.6 mass parts Parts of the initiator are polymerized and are pressure-sensitive and not resistant to electrolyte binders;

The thickness of the first adhesive layer is 4 μm;

The release layer is a PE release film with a thickness of 50 μm.

Use the above method to paste the above double-sided tape on the surface of the positive electrode, and assemble it with the separator and the negative electrode to form a cell, package and inject electrolyte (EC:PC:DMC:EMC:DEC=1:1:1:1:1 ) to prepare a lithium-ion battery, heat-press the lithium-ion battery at 80°C, disassemble the lithium-ion battery after the hot-pressing and observe the position of the double-sided tape. The observation results show that the double-sided tape is pasted on the corresponding position of the diaphragm , and peeled off from the surface of the positive electrode sheet.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit it; although the application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present application. scope.

Claims

A double-sided adhesive tape, wherein the double-sided adhesive tape includes a first adhesive layer, a substrate layer and a second adhesive layer stacked in sequence;

The first adhesive layer includes one or more of silicone, epoxy, polyurethane, polyacrylic, and rubber adhesives, and the adhesive strength of the first adhesive layer is greater than the The adhesive strength of the second adhesive layer.
The double-sided adhesive tape according to claim 1, wherein the second adhesive layer comprises one or more of silicone-based, epoxy-based, polyurethane-based, polyacrylic-based, and rubber-based adhesives.
The double-sided adhesive tape according to claim 1, wherein the thickness of the first adhesive layer is 1-20 μm.
The double-sided adhesive tape according to claim 2, wherein the thickness of the second adhesive layer is 1-20 μm.
The double-sided adhesive tape according to claim 1, wherein the substrate layer comprises one or more of PI, PP, PE, PET.
The double-sided adhesive tape according to claim 5, wherein the thickness of the substrate layer is 3-50 μm.
The double-sided adhesive tape according to claim 1, wherein the double-sided adhesive tape also includes a release layer, and the release layer is arranged on the surface of the first bonding layer away from the substrate layer, and the release layer It is one or more of PET release film, OPP release film, composite release film, glassine release paper, and CCK release paper.
The double-sided adhesive tape according to claim 7, wherein the thickness of the release layer is 3-100 μm.
A lithium-ion battery, wherein the lithium-ion battery includes a positive electrode sheet, a separator and a negative electrode sheet, the negative electrode sheet includes a negative electrode current collector and a negative electrode active layer arranged on at least one surface of the negative electrode current collector, and the surface of the negative electrode current collector Negative tabs are provided;

The surface of the diaphragm is pasted with the double-sided tape according to any one of claims 1-8, and the vertical projection area of the negative tab on the diaphragm falls within the vertical projection area of the double-sided tape on the diaphragm .
The lithium-ion battery according to claim 9, wherein the first adhesive layer of the double-sided adhesive tape comprises a hot-melt type and electrolyte-resistant adhesive, and the second adhesive layer comprises a pressure-sensitive adhesive that is not resistant to electrolysis. liquid adhesive.