CN111477839A

CN111477839A - Manufacturing method of battery pole piece and battery pole piece

Info

Publication number: CN111477839A
Application number: CN202010457246.7A
Authority: CN
Inventors: 唐元鑫; 田秀君; 李敏; 范佳臻; 方耀国
Original assignee: Hunan Xinminya New Energy Technology Co Ltd; Sichuan Xinminya Battery Technology Co Ltd; Suzhou Lingwei New Energy Technology Co Ltd
Current assignee: Hunan Xinminya New Energy Technology Co Ltd; Sichuan Xinminya Battery Technology Co Ltd; Suzhou Lingwei New Energy Technology Co Ltd
Priority date: 2020-05-26
Filing date: 2020-05-26
Publication date: 2020-07-31

Abstract

According to the battery pole piece manufacturing method and the battery pole piece, dry PTC material particles, dry conductive agent particles and dry adhesive particles are mixed and extruded to form a PTC dry film, the PTC dry film is adhered to the surface of a current collector through conductive adhesive, then the PTC dry film is heated and cured to form a PTC layer, and finally an active material layer is covered on the surface of the PTC layer to manufacture the battery pole piece. The battery pole piece manufacturing method and the battery pole piece adopt the dry PTC layer preparation process, do not need organic solvents, and are more environment-friendly, economical and safe.

Description

Manufacturing method of battery pole piece and battery pole piece

Technical Field

The application relates to the field of battery manufacturing, in particular to a manufacturing method of a battery pole piece and the battery pole piece.

Background

At present, lithium batteries are widely used in various occasions, and therefore, the safety performance of the lithium batteries is particularly important. In the use process of the lithium battery, if conditions such as internal and external short circuit, overcharge and the like occur, a large amount of heat can be released in the lithium battery in a short time, so that heat diffusion occurs, and safety accidents such as fire, explosion and the like occur to a lithium battery pack. In order to improve the safety performance of the lithium battery, a safety mechanism is established inside the lithium battery, in the manufacturing process of the battery, a PTC material can be adopted as a bottom coating of an active material in a lithium battery pole piece, when a large amount of heat is generated inside the lithium battery and the internal temperature is increased rapidly, the internal resistance of the PTC material is increased exponentially, so that the electronic transmission between the active material and a current collector is effectively blocked, and the safety performance of the lithium battery is further improved. In the prior art, the PTC primer coating is generally prepared by mixing and dispersing a PTC material, a conductive material and an adhesive in an organic solvent to form slurry, coating the dispersed slurry on a current collector by using a coating device, and drying the current collector. In the process of manufacturing the battery pole piece, the organic solvent is required to be used and volatilized into gas after being dried, and the gas of the organic solvent can not be directly discharged and needs special equipment for recycling. Therefore, the method for manufacturing the battery pole piece in the prior art is not environment-friendly enough, and has the risks of volatilization and leakage of organic solvent gas and potential safety hazard.

In order to solve the problems that the organic solvent is not environment-friendly and has potential safety hazards such as leakage, a new manufacturing method of the battery pole piece and a new battery pole piece are needed.

Disclosure of Invention

The technical scheme of the application aims to solve the problems that the organic solvent is not environment-friendly and has potential safety hazards such as leakage.

Therefore, the application provides a new battery pole piece manufacturing method and a new battery pole piece. According to the method, dry PTC material particles, dry conductive agent particles and dry adhesive particles are mixed and extruded to form a PTC dry film, the PTC dry film is adhered to the surface of a current collector through a conductive adhesive, then the PTC dry film is heated and cured to form a PTC layer, and finally an active material layer is covered on the surface of the PTC layer to form the battery pole piece. The battery pole piece manufacturing method and the battery pole piece adopt the dry PTC layer preparation process, do not need organic solvents, and are more environment-friendly, economical and safe.

One aspect of the present application provides a method for manufacturing a battery pole piece, including: forming a conductive adhesive layer on the surface of the current collector; and forming a PTC layer on the surface of the conductive adhesive layer, wherein the PTC layer is prepared by mixing and sintering PTC material particles, conductive agent particles and adhesive particles.

In some embodiments, the forming a PTC layer on the surface of the conductive adhesive layer includes: uniformly mixing the dried PTC material particles, the dried conductive agent particles, and the dried binder particles; pressing and molding the uniformly mixed PTC mixture to form a PTC dry film; and adhering the PTC dry film to the surface of the conductive adhesive layer.

In some embodiments, the forming a PTC layer on the surface of the conductive adhesive layer further includes: and heating and curing the PTC dry film adhered to the surface of the conductive adhesive layer to form the PTC layer.

In some embodiments, the PTC layer has a thickness of 3-10 μm, and the heating temperature is 30-80 ℃.

In some embodiments, the method for manufacturing a battery pole piece further includes: and forming an active material layer on the surface of the PTC layer, wherein the active material layer is one of a positive electrode active material layer and a negative electrode active material layer.

In some embodiments, the PTC material comprises at least one of a ceramic PTC material and an organic polymeric PTC material.

In some embodiments, the proportion of the PTC material in the PTC layer is 30% to 90%.

In some embodiments, the proportion of the conductive agent in the PTC layer is 1% to 30%.

In some embodiments, the proportion of the binder in the PTC layer is 1% to 30%.

The application also provides a battery pole piece, which comprises a current collector, a conductive adhesive layer and a PTC layer, wherein the conductive adhesive layer covers the surface of the current collector; the PTC layer covers the surface of the conductive adhesive layer, and is made by mixing and sintering PTC material particles, conductive agent particles and adhesive particles.

In some embodiments, the battery pole piece further comprises an active material layer covering the surface of the PTC layer, wherein the active material layer is one of a positive active material layer and a negative active material layer.

In some embodiments, the PTC layer has a thickness of 3 to 10 μm.

According to the technical scheme, the manufacturing method of the battery pole piece comprises the steps of mixing and extruding dry PTC material particles, dry conductive agent particles and dry adhesive particles to form a PTC dry film, adhering the PTC dry film to the surface of a current collector through conductive adhesives, heating and curing the PTC dry film to form a PTC layer, and finally covering an active material layer on the surface of the PTC layer to manufacture the battery pole piece. The battery pole piece manufacturing method and the battery pole piece adopt the dry PTC layer preparation process, do not need organic solvents, and are more environment-friendly, economical and safe.

Other functions of the present application will be partially set forth in the following description. The contents of the following figures and examples will be apparent to those of ordinary skill in the art in view of this description. The inventive aspects of this application can be fully explained by the practice or use of the methods, apparatus and combinations described in the detailed examples below.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic cross-sectional structure diagram of a battery pole piece provided in an embodiment of the present application;

fig. 2 is a flowchart of a method for manufacturing a battery pole piece according to an embodiment of the present disclosure;

fig. 3 is a schematic view of a pressed PTC composition according to an embodiment of the present application.

Detailed Description

The following description is presented to enable any person skilled in the art to make and use the present disclosure, and is provided in the context of a particular application and its requirements. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present application. Thus, the present application is not limited to the embodiments shown, but is to be accorded the widest scope consistent with the claims.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. For example, as used herein, the singular forms "a", "an" and "the" may include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises," "comprising," "includes," and/or "including," when used in this specification, are intended to specify the presence of stated integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The term "A on B" as used in this specification means that A is either directly adjacent (above or below) B or indirectly adjacent (i.e., separated by some material) to B; the term "A within B" means that A is either entirely within B or partially within B.

These and other features of the present application, as well as the operation and function of the related elements of structure and the combination of parts and economies of manufacture, may be significantly improved upon consideration of the following description. All of which form a part of this application, with reference to the accompanying drawings. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the application. It should also be understood that the drawings are not drawn to scale.

The application provides a battery pole piece on the one hand, and provides a manufacturing method of the battery pole piece on the other hand. The battery pole piece can be a battery pole piece of a lithium battery, and can also be a battery pole piece of other batteries, such as a battery pole piece of a storage battery and the like. Purely for the sake of illustration, the following description of the present application will be described by way of example for a lithium battery. The battery pole piece can be divided into a positive pole piece and a negative pole piece. Fig. 1 is a schematic cross-sectional structure diagram of a battery pole piece 100 according to an embodiment of the present disclosure. As shown in fig. 1, the battery pole piece 100 may include a current collector 110, a conductive adhesive layer 130, and a PTC layer 150. In some embodiments, battery pole piece 100 can also include an active material layer 170.

The current collector 110 is a base material of the battery electrode sheet 100 and is a metal structure for collecting current. The current collector 110 may be an aluminum foil or a copper foil. When the battery electrode sheet 100 is the positive electrode sheet, the current collector 110 may be an aluminum foil or a carbon-coated aluminum foil. When the battery electrode 100 is the negative electrode, the current collector 110 may be a copper foil or a carbon-coated copper foil.

The conductive adhesive layer 130 may cover the surface of the current collector 110. The conductive adhesive layer 130 is made of conductive adhesive. The conductive adhesive is an adhesive with certain conductivity after being cured or dried. It can connect multiple conductive materials together to form an electrical path between the connected materials. The conductive adhesive may be a silver-based conductive adhesive, a gold-based conductive adhesive, a copper-based conductive adhesive, or a carbon-based conductive adhesive.

The PTC layer 150 may cover the surface of the conductive adhesive layer 130. The PTC layer 150 may be connected to the current collector 110 through the conductive adhesive layer 130. The PTC layer 150 is made by mixing and sintering PTC (Positive Temperature Coefficient thermal) material particles, conductive agent particles, and binder particles. The PTC layer 150 is formed by mixing dried PTC material particles, dried conductive agent particles, and dried binder particles, pressing the mixture into a film, adhering the film to the surface of the current collector 110 through the conductive agent layer 130, and heating and curing the film. In the manufacturing process, moisture and organic solvent are not added except for moisture contained in the PTC material particles, the conductive agent particles, and the binder particles themselves, and thus, the manufacturing process of the PTC layer 150 is very environment-friendly, economical, and safe. The thickness of the PTC layer 150 is related to the electrical conductivity of the battery pole piece 100. An excessively thick PTC layer 150 may reduce the electrical conductivity of the battery pole piece 100. On the other hand, too thin the PTC layer 150 may affect the safety protection performance. In some embodiments, the PTC layer 150 has a thickness of 3 to 10 μm.

The active material layer 170 may cover the surface of the PTC layer 150. The active material layer 170 is made by coating an active material slurry on the surface of the PTC layer 150 by a coater and drying. The active material layer 170 serves as the positive and negative electrodes of the battery pole piece 100. The active material layer 170 may be one of a positive electrode active material layer and a negative electrode active material layer. The active material layer 170 may be made of a material including an active material, a binder, a conductive agent, and the like. The active material may include a positive electrode active material and a negative electrode active material. When the battery pole piece 100 is the positive pole piece, the active material layer 170 is the positive active material layer, and the active material is the positive active material. When the battery pole piece 100 is the negative pole piece, the active material layer 170 is the negative active material layer, and the active material is the negative active material. The positive active material can be one or more of lithium cobaltate, lithium manganate, nickel cobalt manganese ternary material, lithium iron phosphate and the like. The negative active material can be one or more of graphite, silicon composite material, lithium titanate and the like.

Another aspect of the present disclosure provides a method for manufacturing a battery electrode 100. Fig. 2 is a flowchart 200 of a method for manufacturing the battery pole piece 100 according to an embodiment of the present disclosure. The method may include:

s210: a conductive adhesive layer 130 is formed on the surface of the current collector 110.

Before the PTC layer 150 is formed, a conductive adhesive layer 130 needs to be adhered or coated on the surface of the current collector 110 to facilitate the adhesion of the PTC layer 150 to the current collector 110.

S230: the PTC layer 150 is formed on the surface of the conductive adhesive layer 130.

The PTC layer 150 is made by mixing and sintering PTC material particles, conductive agent particles, and binder particles. Specifically, the PTC layer 150 is formed by mixing dried PTC material particles, dried conductive agent particles, and dried binder particles, pressing the mixture into a film, adhering the film to the surface of the current collector 110 through the conductive adhesive layer 130, and heating and curing the film. The heating temperature is 30-80 ℃. In the manufacturing process, moisture and organic solvent are not added except for moisture contained in the PTC material particles, the conductive agent particles, and the binder particles themselves, and thus, the manufacturing process of the PTC layer 150 is very environment-friendly, economical, and safe.

In some embodiments, the step S230 of forming the PTC layer 150 on the surface of the conductive adhesive layer 130 may specifically include:

s231: mixing the dried particles of the PTC material, the dried particles of the conductive agent, and the dried particles of the binder uniformly.

The raw materials of the PTC layer 150 are the dried PTC material particles, the dried conductive agent particles, and the dried binder particles. No moisture and no organic solvent are added, other than the moisture contained in the raw material itself. Mixing and sufficiently stirring the dried particles of the PTC material, the dried particles of the conductive agent, and the dried particles of the binder, the particles of the PTC material and the particles of the conductive agent being bonded together by the particles of the binder.

The PTC material may include at least one of a ceramic PTC material and an organic polymeric PTC material. Wherein the ceramic PTC material may comprise one or more of barium titanate, strontium-doped barium titanate, tantalum-doped barium titanate, niobium-doped barium titanate. The organic polymeric PTC material may comprise one or more of polyolefins, polynitriles, polyesters, fluoropolymers, polyacrylic acid, poly styrene butadiene rubber, polyimide, polyaniline. The proportion of the PTC material in the PTC layer 150 may be 30% to 90%, including 30% and 90%.

The conductive agent may include one or more of conductive graphite, conductive carbon black, acetylene black, ketjen black, carbon nanofibers, carbon nanotubes, graphene. The proportion of the conductive agent in the PTC layer 150 may be 1% to 30%, including 1% and 30%.

The adhesive is a substance with viscosity, and can bond two or more than two separated substances together. The adhesive is a fibrillatable adhesive. Wherein the fibrillatable binder may comprise one or more of polytetrafluoroethylene, polyvinylidene fluoride, polyacrylics, polyacrylates, polyacrylonitrile. The fibrillatable binder is ground into particulate form prior to mixing, which may be one or more of hammer milling, rod milling or jet milling. The proportion of the binder in the PTC layer 150 is 1% to 30%, including 1% and 30%.

S233: the uniformly mixed PTC mixture 151 is press-molded to form a PTC dry film 153.

After the raw materials of the PTC layer 150 are uniformly mixed, the uniformly mixed PTC mixture 151 needs to be pressed into a film. Fig. 3 is a schematic diagram 300 of a pressed PTC composition 151 according to an embodiment of the present disclosure. As shown in fig. 3, the PTC mixture 151 is pressed by a roller press 310, and the PTC mixture 151 is extruded from an outlet 311 and rolled by a roller 313 to form a PTC dry film 153. Since the PTC dry film does not contain excessive moisture and organic solvent, the press-formed PTC dry film 153 can be self-supporting. The rollers 313 are present in pairs, and the number of rollers 313 may be 2, 4 or even more.

S235: the PTC dry film 153 is adhered to the surface of the conductive paste layer 130.

The press-formed PTC dry film 153 is adhered to the surface of the conductive adhesive layer 130, and the PTC dry film 153 is adhered to the surface of the current collector 110 by the adhesiveness of the conductive adhesive layer 130.

In some embodiments, step S230 may further include:

s237: the PTC dry film 153 adhered to the surface of the conductive adhesive layer 130 is heated and cured to form the PTC layer 150.

After the PTC dry film 153 is adhered to the surface of the conductive layer 130, the connection between the PTC dry film 153 and the current collector 110 needs to be further cured. Therefore, the PTC dry film 153 adhered to the surface of the conductive adhesive layer 130 is heated and cured to form the PTC layer 150. Wherein the heating temperature is 30-80 ℃. The thickness of the PTC layer 150 formed after heating and curing is 3-10 μm.

Step S230 is exemplified below.

For example, dried particles of strontium-doped barium titanate material, dried particles of carbon black, and ground dried particles of polytetrafluoroethylene are mixed in a ratio of 7: 2: 1 in a stirrer, and fully stirring for 8 hours; rolling the blended mixture through a roller press 310 as shown in fig. 3 to form a self-supporting PTC dry film 153; the self-supporting PTC dry film 153 prepared in the above step is adhered to the current collector 110 coated with the conductive adhesive layer 130 and heated to 80 ℃ to form the PTC layer 150 of the battery tab 100.

For another example, dried polyaniline material particles, dried conductive graphite particles, and dried polytetrafluoroethylene particles milled by a jet milling apparatus are mixed in a ratio of 8: 1: 1 in a stirrer, and fully stirring for 8 hours; rolling the blended mixture through a roller press 310 as shown in fig. 3 to form a self-supporting PTC dry film 153; the self-supporting PTC dry film 153 prepared in the above step is adhered to the current collector 110 coated with the conductive adhesive layer 130 and heated to 70 c to form the PTC layer 150 of the battery tab 100.

For another example, dried polyaniline material particles, dried carbon tube particles, dried conductive carbon black particles, dried polytetrafluoroethylene ground by hammer milling, and dried polyvinylidene fluoride ground by hammer milling are mixed in a ratio of 80: 7: 3: 5: 5 in a stirrer, and fully stirring for 8 hours; rolling the blended mixture through a roller press 310 as shown in fig. 3 to form a self-supporting PTC dry film 153; the self-supporting PTC dry film 153 prepared in the above step is adhered to the current collector 110 coated with the conductive adhesive layer 130 and heated to 70 c to form the PTC layer 150 of the battery tab 100.

For another example, dried particles of polyacrylic acid material, dried carbon tubes, dried particles of conductive carbon black, dried particles of polytetrafluoroethylene milled by air flow, and dried particles of polyacrylate milled by air flow are mixed in a ratio of 80: 7: 3: 8: 2 in a stirrer, and fully stirring for 8 hours; rolling the blended mixture through a roller press 310 as shown in fig. 3 to form a self-supporting PTC dry film 153; the self-supporting PTC dry film 153 prepared in the above step is adhered to the current collector 110 coated with the conductive adhesive layer 130 and heated to 70 c to form the PTC layer 150 of the battery tab 100.

For another example, dried particles of polyacrylic acid material, dried particles of graphene, and dried particles of polytetrafluoroethylene milled by air flow milling are mixed in a ratio of 90: 5: 5 in a stirrer, and fully stirring for 8 hours; rolling the blended mixture through a roller press 310 as shown in fig. 3 to form a self-supporting PTC dry film 153; the self-supporting PTC dry film 153 prepared in the above step is adhered to the current collector 110 coated with the conductive adhesive layer 130 and heated to 70 c to form the PTC layer 150 of the battery tab 100.

In some embodiments, the method for manufacturing the battery pole piece 100 may further include:

s250: an active material layer 170 is formed on the surface of the PTC layer 150.

The active material layer 170 is made by coating an active material slurry on the surface of the PTC layer 150 by a coater and drying. The active material layer 170 serves as the positive and negative electrodes of the battery pole piece 100. The active material layer 170 is one of the positive electrode active material layer and the negative electrode active material layer. When the battery pole piece 100 is the positive pole piece, the active material layer 170 is the positive active material layer. When the battery pole piece 100 is the negative pole piece, the active material layer 170 is the negative active material layer. The active materials are described above and will not be described in detail herein.

To sum up, in the manufacturing method of the battery pole piece 100 provided by the present application, the conductive adhesive layer 130 is firstly covered on the surface of the current collector 110; then, mixing and extruding the dried PTC material particles, the dried conductive agent particles and the dried adhesive particles to form a PTC dry film 153, and adhering the PTC dry film 153 on the surface of the current collector 110 through the conductive adhesive layer 130; then, the PTC dry film 153 is heated and cured to form a PTC layer 150; finally, the active material layer 170 is covered on the surface of the PTC layer 150 to form the battery pole piece 100. The whole process for preparing the PTC layer 150 adopts a dry preparation process, does not need to add an organic solvent, and is more environment-friendly, economic and safe.

In conclusion, upon reading the present detailed disclosure, those skilled in the art will appreciate that the foregoing detailed disclosure can be presented by way of example only, and not limitation. Those skilled in the art will appreciate that the present application is intended to cover various reasonable variations, adaptations, and modifications of the embodiments described herein, although not explicitly described herein. Such alterations, improvements, and modifications are intended to be suggested by this application and are within the spirit and scope of the exemplary embodiments of the application.

Furthermore, certain terminology has been used in this application to describe embodiments of the application. For example, "one embodiment," "an embodiment," and/or "some embodiments" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. Therefore, it is emphasized and should be appreciated that two or more references to "an embodiment" or "one embodiment" or "an alternative embodiment" in various portions of this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined as suitable in one or more embodiments of the application.

It should be appreciated that in the foregoing description of embodiments of the present application, various features are grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure aiding in the understanding of one feature. This is not to be taken as an admission that any of the features of the claims are essential, and it is fully possible for a person skilled in the art to extract some of them as separate embodiments when reading the present application. That is, embodiments in the present application may also be understood as an integration of multiple sub-embodiments. And each sub-embodiment described herein is equally applicable to less than all features of a single foregoing disclosed embodiment.

Each patent, patent application, publication of a patent application, and other material, such as articles, books, descriptions, publications, documents, articles, and the like, cited herein is hereby incorporated by reference. All matters hithertofore set forth herein except as related to any prosecution history, may be inconsistent or conflicting with this document or any prosecution history which may have a limiting effect on the broadest scope of the claims. Now or later associated with this document. For example, if there is any inconsistency or conflict in the description, definition, and/or use of terms associated with any of the included materials with respect to the terms, descriptions, definitions, and/or uses associated with this document, the terms in this document are used.

Finally, it should be understood that the embodiments of the application disclosed herein are illustrative of the principles of the embodiments of the present application. Other modified embodiments are also within the scope of the present application. Accordingly, the disclosed embodiments are presented by way of example only, and not limitation. Those skilled in the art may implement the present application in alternative configurations according to the embodiments of the present application. Thus, embodiments of the present application are not limited to those precisely described in the application.

Claims

1. A manufacturing method of a battery pole piece is characterized by comprising the following steps:

forming a conductive adhesive layer on the surface of the current collector; and

a PTC layer is formed on the surface of the conductive adhesive layer,

wherein, the PTC layer is prepared by mixing and sintering PTC material particles, conductive agent particles and adhesive particles.

2. The method of claim 1, wherein the forming a PTC layer on the surface of the conductive adhesive layer comprises:

uniformly mixing the dried PTC material particles, the dried conductive agent particles, and the dried binder particles;

pressing and molding the uniformly mixed PTC mixture to form a PTC dry film; and

and adhering the PTC dry film to the surface of the conductive adhesive layer.

3. The method of claim 2, wherein the forming a PTC layer on the surface of the conductive adhesive layer further comprises:

and heating and curing the PTC dry film adhered to the surface of the conductive adhesive layer to form the PTC layer.

4. The method for manufacturing the battery pole piece according to claim 3, wherein the thickness of the PTC layer is 3-10 μm, and the heating temperature is 30-80 ℃.

5. The method of making a battery pole piece of claim 1, further comprising:

and forming an active material layer on the surface of the PTC layer, wherein the active material layer is one of a positive electrode active material layer and a negative electrode active material layer.

6. The method of making a battery pole piece of claim 1, wherein the PTC material comprises at least one of a ceramic PTC material and an organic polymeric PTC material.

7. The method of claim 1, wherein the PTC material is present in the PTC layer in a proportion of 30% to 90%.

8. The method of claim 1, wherein the PTC layer comprises 1% to 30% of the conductive agent.

9. The method of claim 1, wherein the proportion of the binder in the PTC layer is 1% to 30%.

10. A battery pole piece, comprising:

a current collector;

the conductive adhesive layer covers the surface of the current collector; and

a PTC layer covering the surface of the conductive adhesive layer,

11. The battery pole piece of claim 10, further comprising an active material layer overlying the PTC layer surface, the active material layer being one of a positive active material layer and a negative active material layer.

12. The battery pole piece of claim 10, wherein the PTC layer has a thickness of 3 to 10 μm.