CN117810375A

CN117810375A - Dry pole piece preparation method, pole piece and battery

Info

Publication number: CN117810375A
Application number: CN202311850437.XA
Authority: CN
Inventors: 董童明; 许航; 严正琦; 魏建良
Original assignee: Jiangsu Zenio New Energy Battery Technologies Co Ltd
Current assignee: Jiangsu Zenio New Energy Battery Technologies Co Ltd
Priority date: 2023-12-29
Filing date: 2023-12-29
Publication date: 2024-04-02

Abstract

The invention provides a preparation method of a dry pole piece, a pole piece and a battery, and particularly relates to the technical field of secondary batteries. The preparation method comprises the following steps: A. mixing an electrode active material, a conductive agent and a porous organic framework to obtain mixed powder, adding a binder into the mixed powder, and performing fibrosis treatment to obtain a fibrosis material; B. granulating the fiberized material, then calendaring and forming to obtain a dry membrane, and attaching the dry membrane to at least one side of a current collector to obtain a dry pole piece. According to the preparation method provided by the invention, the Porous Organic Frameworks (POFs) are added in the dry electrode mixing process, so that the POFs are stable in structure, large in specific surface area and easy to modify in framework, rolling is not affected, compaction density can be ensured, porosity can be improved, and performance of a battery can be improved.

Description

Dry pole piece preparation method, pole piece and battery

Technical Field

The invention relates to the technical field of secondary batteries, in particular to a preparation method of a dry pole piece, a pole piece and a battery.

Background

In recent years, the global new energy automobile market is in a rapid development period, and the lithium ion battery is used as a power first choice of the new energy automobile to be rapidly developed. Currently, mass industrialization of pure electric vehicles still faces the problems of "charge anxiety", "mileage anxiety" and further cost reduction. Among them, how to greatly improve the rate capability and energy density of lithium ion batteries is the focus of researchers. The electrode is used as a main component of the lithium ion battery, and the performance of the energy storage device is deeply influenced.

The conventional wet coating process has reached a limit for increasing the bulk density of the electrode, and development of a new electrode preparation process is urgently required. The dry electrode technology can omit procedures such as drying, NMP solvent recovery and the like, greatly simplifies the production flow, improves the production efficiency and saves the cost. Meanwhile, the dry electrode technology can easily control the thickness of the electrode and the uniformity of the thick electrode, does not generate cracks, and has unique advantages in the aspect of preparing the thick electrode.

However, in the dry electrode production process in the prior art, electrode materials, conductive agents and binders are mixed and fibrillated to form electrode powder, the electrode powder is rolled for a plurality of times to form a membrane with good appearance and high strength, and the membrane and a current collector are compounded together in a hot pressing mode. The pole piece is repeatedly rolled, so that the pole piece compaction density is overlarge, the porosity of the pole piece is low, the amount of electrolyte absorbed is reduced, the electrolyte is difficult to permeate into the pole piece, the lithium ion transmission resistance is increased, and the charge transfer resistance of an electrode/electrolyte interface is increased, so that the rate performance is deteriorated.

In view of this, the present invention has been made.

Disclosure of Invention

The invention aims to provide a preparation method of a dry pole piece, which aims to solve the technical problems that the existing dry process is easy to cause excessive pole piece compaction density, low pole piece porosity, reduced amount of absorbed electrolyte, difficult penetration of the electrolyte into the pole piece, increased lithium ion transmission resistance and electrode/electrolyte interface charge transfer resistance, and poor multiplying power performance.

The second object of the present invention is to provide a pole piece.

It is a further object of the present invention to provide a battery.

In order to solve the technical problems, the invention adopts the following technical scheme:

the first aspect of the invention provides a preparation method of a dry pole piece, which comprises the following steps:

A. mixing an electrode active material, a conductive agent and a porous organic framework to obtain mixed powder, adding a binder into the mixed powder, and performing fibrosis treatment to obtain a fibrosis material;

B. granulating the fiberized material, then calendaring to obtain a dry membrane, and attaching the dry membrane to at least one side of a current collector to obtain the dry pole piece.

Further, the porous organic framework comprises at least one of a metal organic framework, a covalent organic framework, and a hydrogen bond organic framework.

Preferably, the porous organic framework has a specific surface area of 50m ² /g-6000m ² And/g, the pore diameter is 0.5nm-50nm.

Further, in the step A, the fiberizing material comprises 90-97 parts of electrode active material, 1-5 parts of conductive agent, 0.1-5 parts of porous organic frame and 0.1-10 parts of binder according to parts by weight.

Further, the electrode active material includes a positive electrode active material and a negative electrode active material.

Preferably, the positive electrode active material includes at least one of lithium iron phosphate, lithium manganese iron phosphate, lithium manganate, lithium cobaltate, lithium nickel cobalt manganate, and lithium nickel cobalt aluminate.

Preferably, the negative active material includes at least one of lithium titanate, silicon carbon composite, graphite, and silicon oxide.

Further, the conductive agent includes at least one of acetylene black, conductive carbon black, ketjen black, graphene, carbon nanotubes, and carbon fibers.

Preferably, the binder includes at least one of polyvinylidene fluoride, acrylic resin, polytetrafluoroethylene, and styrene-butadiene rubber.

Further, in the step A, the rotation speed of the mixing is 100rpm-1000rpm, and the time is 5min-20min.

Preferably, in the step A, the rotating speed of the fiberizing treatment is 3000rpm-20000rpm, and the time is 5min-30min.

Further, the fiberizing treatment is performed in a single screw extruder, a twin screw extruder, a granulator, a kneader, a high-speed disperser, or a jet mill.

In the step B, the dry film with preset thickness is obtained through one-time film forming or multiple film reduction by calendaring. Wherein, the primary film forming means that raw material particles enter a roller rotating in the same direction and are compacted, the density is continuously increased, the thickness is continuously reduced, and the dry film is obtained after the material particles reach the preset thickness; the repeated film reduction is to compact the raw material particles to prepare a semi-finished product of the dry film, and then to roll for multiple times by adjusting the interval between the two rollers to obtain the dry film with preset thickness.

Preferably, in the step B, the bonding mode includes flat plate hot press bonding.

Preferably, the temperature of the hot press lamination of the flat plate is 80-200 ℃ and the time is 5-60 s.

The second aspect of the invention provides the pole piece prepared by the preparation method.

Further, the porosity of the dry pole piece is 30% -55%.

A third aspect of the invention provides a battery comprising a dry pole piece as described above.

Compared with the prior art, the invention has at least the following beneficial effects:

according to the preparation method provided by the invention, the Porous Organic Frameworks (POFs) are added in the dry electrode mixing process, so that the POFs are stable in structure, large in specific surface area and easy to modify in framework, rolling is not affected, compaction density can be ensured, porosity can be improved, and performance of a battery can be improved.

The dry electrode plate provided by the invention is dried by adding a Porous Organic Frame (POFs) in the dry electrode mixing processThe porosity of the pole piece is controlled to be 30% -55%. POFs with high specific surface area not only make lithium ions easily accessible to redox active sites to increase Li per unit area ⁺ Store, and the layered structure of POFs also promotes Li ⁺ Diffusion kinetics. Meanwhile, the porous structure of the POFs increases the porosity of the pole piece, reduces the DCR of the battery, improves the rate capability and prolongs the service life of the battery.

According to the battery provided by the invention, the adopted pole piece is the dry pole piece, so that the energy density of the battery is improved, the porosity of the pole piece is ensured, the infiltration of electrolyte is accelerated, and the overall performance of the battery is improved.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions in the embodiments of the present invention will be clearly and completely described in the following in conjunction with the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments. The components of embodiments of the present invention may be arranged and designed in a wide variety of different configurations.

It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

The porous organic frameworks (Porous Organic Frameworks, POFs for short) are a collective name of metal organic frameworks, covalent organic frameworks and hydrogen bond organic frameworks, and have the remarkable characteristics of large specific surface area, high permanent porosity, good thermal stability and chemical stability and the like.

The metal organic frame Material (MOFs) is an organic-inorganic hybrid material, is formed by self-assembling a metal center and an organic ligand through coordination bonds, and has a highly adjustable pore structure and pore diameter, an extremely high specific surface area and a designable size and shape. MOFs are used in the preparation process of the dry pole piece, so that the porosity of the pole piece can be improved, and the conductivity of the pole piece can be improved.

The covalent organic framework material (COFs) is a porous crystal material, has unique crystallinity and porosity, a framework structure which is easy to regulate and control by the COFs and a strong covalent bond ensure the chemical stability of the COFs in the oxidation-reduction process, and is formed by combining organic structural units through reversible covalent bonds and combining periodically.

Hydrogen-bonded organic framework materials (HOFs) are porous organic framework materials that self-assemble through hydrogen bonding between organic molecules. Because of the inherent weak, flexible, poor directivity, reversibility and other characteristics of hydrogen bonds, HOFs have some differences compared with MOFs and COFs, such as the characteristics of easy purification, strong solution processability, high crystallinity, frame repair by simple recrystallization, high biocompatibility and the like, when the HOFs, the COFs and the MOFs are used in the preparation process of dry pole pieces, the frames of the materials are possibly damaged to a certain extent after the batteries are actually recycled for many times, so that the battery performance is reduced, but compared with the MOFs and the COFs, the HOFs have the structure self-repair and the reproducibility, the HOFs can be subjected to frame repair regeneration through a simple recrystallization process, and the battery can be recycled for a long time, so that the HOFs are significant for large-scale use.

When the weight part of the electrode active material is less than 90 parts, the internal resistance of the battery is increased, the transmission of lithium ions is affected, and the capacity, the multiplying power performance and the charge and discharge efficiency of the battery are reduced; when the weight portion of the electrode active material is higher than 97 portions, the active material is unevenly distributed in the manufacturing process, the utilization rate of the active material in a partial area is reduced, the internal resistance is increased, the conductive agent or the binder is correspondingly reduced, and the rate performance is reduced or the pole piece is fallen. When the weight part of the porous organic framework is less than 0.1 part, the battery performance is not obviously improved; when the weight portion of the porous organic frame is higher than 5 portions, the corresponding portions of the active material, the binder and the conductive agent are reduced, the battery performance has marginal effect, and the battery pole piece may fall off and the multiplying power performance is reduced.

Typically, but not limited to, the weight parts of the electrode active material are 90 parts, 91 parts, 92 parts, 93 parts, 94 parts, 95 parts, 96 parts, or 97 parts; the weight part of the conductive agent is 1 part, 2 parts, 3 parts, 4 parts or 5 parts; the porous organic frame is 0.1 part, 0.5 part, 1 part, 2 parts, 3 parts, 4 parts or 5 parts by weight; the weight portion of the binder is 0.1 portion, 0.5 portion, 1 portion, 3 portions, 5 portions, 7 portions, 9 portions or 10 portions.

Preferably, the positive electrode active material includes at least one of lithium iron phosphate, lithium manganese iron phosphate, lithium manganate, lithium cobaltate, and lithium nickel cobalt manganate.

Preferably, the negative active material includes at least one of lithium titanate, silicon carbon composite material, graphite, and silicon oxide.

The film prepared by the pre-fibrosis is beneficial to the electrolyte to be immersed into the electrode plate, and the pre-fibrosis film is more tightly connected with the conductive agent particles, so that the conductive performance is good, and the multiplying power performance is excellent.

The second aspect of the invention provides the dry pole piece prepared by the preparation method.

According to the dry electrode slice provided by the invention, the Porous Organic Frameworks (POFs) are added in the dry electrode mixing process, so that the POFs with high specific surface area not only enable lithium ions to easily access redox active sites to improve Li in unit area ⁺ Store, and the layered structure of POFs also promotes Li ⁺ Diffusion kinetics. Meanwhile, the porous structure of the POFs increases the porosity of the pole piece, reduces the DCR of the battery, improves the rate capability and prolongs the service life of the battery.

Further, the porosity of the dry pole piece is 30% -55%.

The battery comprises a shell and a battery core arranged in the shell, wherein the battery core comprises a positive electrode plate, a negative electrode plate and a diaphragm arranged between the positive electrode plate and the negative electrode plate, the positive electrode plate, the negative electrode plate and the diaphragm can form the battery core in a lamination or winding mode, and at least one of the positive electrode plate and the negative electrode plate is the dry electrode plate. When the positive plate is a dry-method plate, the electrode active material is a positive electrode active material, and the positive plate is a dry-method plate; when the negative electrode plate is a dry electrode plate, the electrode active material is a negative electrode active material, and the negative electrode plate is a dry electrode plate.

Some embodiments of the present invention will be described in detail below with reference to examples. The following embodiments and features of the embodiments may be combined with each other without conflict. The raw material purchase in the following examples and comparative examples was obtained by commercial purchase unless otherwise specified.

Example 1

The embodiment provides a dry positive plate, which is prepared by the following steps:

1. adding 96 parts of electrode active material nickel cobalt lithium manganate, 1 part of conductive agent SP (carbon black) and 1 part of Covalent Organic Frameworks (COFs) (TPPA-1, roen) into a high-speed dispersing machine for mixing, wherein the rotating speed is 800rpm, and the mixing time is 10min, so as to obtain a mixed material; then 1 part of binder (PTFE) was added, the rotation speed was increased to 12000rpm, and the mixture was fibrillated for 5 minutes to obtain a fibrillated material.

2. The fibrous material is scattered, the fibrous material is changed into uniform fibrous material from fibrous material, the fibrous material of the adhesive is more sufficient, the dispersibility of each component is better, the rolling effect is improved, the energy density of the battery is improved, and the scattered electrode material is rolled by a vertical roller and a horizontal roller to obtain the dry-method positive electrode membrane with the thickness of 90 mu m. And (3) bonding the dry-process anode membrane and the carbon-coated aluminum foil through a flat plate hot press, wherein the flat plate hot press temperature is 160 ℃, and the hot press time is 10 seconds, so that the dry-process anode plate is obtained.

Example 2

1. the Covalent Organic Frameworks (COFs) of example 1 were replaced with hydrogen bonded organic frameworks (HOFs) (HOF-100, western amp Ji Yue organisms) and the remaining starting materials and methods were the same as in this step of example 1 and are not described in detail herein.

2. As in example 1.

Example 3

1. unlike the procedure of example 1, the amount of the electrode active material lithium nickel cobalt manganese oxide was 93 parts, the amount of the Covalent Organic Frameworks (COFs) was 5 parts, and the remaining materials and methods were the same as those of the procedure of example 1, and will not be described again.

2. As in example 1.

Example 4

1. 90 parts of electrode active material nickel cobalt lithium manganate, 5 parts of conductive agent SP (carbon black) and 0.1 part of Covalent Organic Frameworks (COFs) (TPPA-1, roen) are added into a high-speed dispersing machine to be mixed, the rotating speed is 800rpm, and the mixing time is 10min, so that a mixed material is obtained; then 1 part of binder (PTFE) was added, the rotation speed was increased to 12000rpm, and the mixture was fibrillated for 5 minutes to obtain a fibrillated material.

2. As in example 1.

Example 5

1. 97 parts of electrode active material nickel cobalt lithium manganate, 5 parts of conductive agent SP (carbon black) and 5 parts of Covalent Organic Frameworks (COFs) (TPPA-1, roen) are added into a high-speed dispersing machine to be mixed, the rotating speed is 800rpm, and the mixing time is 10min, so that a mixed material is obtained; then 10 parts of binder (PTFE) was added, the rotation speed was increased to 12000rpm, and the mixture was fibrillated for 5 minutes to obtain a fibrillated material.

2. As in example 1.

Example 6

1. as in example 1.

2. And scattering the fiberized material, and rolling the scattered electrode material by a vertical roller and a horizontal roller to obtain the dry-method positive electrode film with the thickness of 90 mu m. And (3) bonding the dry-process positive electrode membrane and the carbon-coated aluminum foil through a flat plate hot press, wherein the flat plate hot press temperature is 80 ℃, and the hot press time is 60 seconds, so that the dry-process positive electrode plate is obtained.

Example 7

1. the Covalent Organic Frameworks (COFs) of example 1 were replaced with Metal Organic Frameworks (MOFs) (ZIF-67, iia), the remaining materials and methods were the same as in this step of example 1 and are not described here in detail.

2. As in example 1.

Example 8

1. 105 parts of electrode active material nickel cobalt lithium manganate, 1 part of conductive agent SP (carbon black) and 1 part of Covalent Organic Frameworks (COFs) (TPPA-1, roen) are added into a high-speed dispersing machine to be mixed, the rotating speed is 800rpm, and the mixing time is 10min, so that a mixed material is obtained; then 1 part of binder (PTFE) was added, the rotation speed was increased to 12000rpm, and the mixture was fibrillated for 5 minutes to obtain a fibrillated material.

2. As in example 1.

Example 9

1. adding 96 parts of electrode active material nickel cobalt lithium manganate, 1 part of conductive agent SP (carbon black) and 15 parts of Covalent Organic Frameworks (COFs) (TPPA-1, roen) into a high-speed dispersing machine for mixing, wherein the rotating speed is 800rpm, and the mixing time is 10min, so as to obtain a mixed material; then 1 part of binder (PTFE) was added, the rotation speed was increased to 12000rpm, and the mixture was fibrillated for 5 minutes to obtain a fibrillated material.

2. As in example 1.

Example 10

The embodiment provides a dry-process negative plate, which is prepared by the following steps:

1. 96 parts of lithium titanate serving as an electrode active material, 1 part of conductive agent SP (carbon black) and 1 part of Covalent Organic Frameworks (COFs) (TPPA-1, roen) are added into a high-speed dispersing machine to be mixed, the rotating speed is 800rpm, and the mixing time is 10min, so that a mixed material is obtained; then 1 part of binder (PTFE) was added, the rotation speed was increased to 12000rpm, and the mixture was fibrillated for 5 minutes to obtain a fibrillated material.

2. As in example 1.

Comparative example 1

The comparative example provides a dry positive plate, which is prepared by the following steps:

1. unlike the procedure of example 1, covalent Organic Frameworks (COFs) are not added to the starting materials, and the remaining starting materials and methods are the same as the procedure of example 1 and are not described in detail herein.

2. As in example 1.

Comparative example 2

1. adding 96 parts of electrode active material nickel cobalt lithium manganate, 1 part of conductive agent SP (carbon black) and 1 part of Covalent Organic Frameworks (COFs) (TPPA-1, roen) into a high-speed dispersing machine for mixing, wherein the rotating speed is 800rpm, and the mixing time is 10min, so as to obtain a mixed material; 1 part of a binder (PTFE) was then added and mixed and granulated.

2. And rolling the electrode material after mixing granulation through a vertical roller and a horizontal roller to obtain the dry-method anode film with the thickness of 90 mu m. And (3) bonding the dry-process anode membrane and the carbon-coated aluminum foil through a flat plate hot press, wherein the flat plate hot press temperature is 160 ℃, and the hot press time is 10 seconds, so that the dry-process anode plate is obtained.

Test example 1

The dry electrode sheets obtained in examples 1 to 10 and comparative examples 1 to 2 were subjected to a porosity test, and the porosity of the dry electrode sheet was measured by mercury intrusion method with reference to national standard GB/T21650.1-2008/ISO 15901-1:2005, and the data obtained are shown in Table 1 below.

TABLE 1

	Porosity (%)
		Example 1	45
Example 2	44
		Example 3	48
Example 4	40
		Example 5	49
Example 6	48
		Example 7	41
Example 8	38
		Example 9	52
Example 10	45
		Comparative example 1	25
Comparative example 2	50

As can be seen from table 1, the porosity is significantly improved in examples 1 and 2 after the dry pole piece is added with COFs/HOFs as compared with comparative example 1, and the corresponding porosity is increased as the COFs content is increased, which shows that the COFs/HOFs can significantly improve the porosity of the pole piece. From the data of example 1 and comparative example 2, it can be seen that fibrosis also reduces the porosity of the pole piece.

Test example 2

1. Preparation of a cell

The dry positive electrode sheets obtained in examples 1 to 9 and comparative examples 1 to 2 were manufactured into positive electrode sheets having a diameter of 13mm using a sheet punching machine, and metallic lithium sheets were used as counter electrodes.

Uniformly mixing graphite C, conductive carbon black Super P, a thickener CMC (sodium carboxymethylcellulose) and a binder SBR (styrene butadiene rubber) with deionized water according to a mass ratio of 96.4:1:1.2:1.4 to prepare a negative electrode slurry; uniformly coating the negative electrode slurry on the front and back sides of the copper foil according to the same surface density, carrying out forced air drying at 80-120 ℃, and then carrying out cold pressing and die cutting to obtain the negative electrode plate.

The positive electrode plate, the counter electrode and the negative electrode plate, a polypropylene microporous membrane (Celgard 2400) is used as a diaphragm, and 1mol/L LiPF is used ₆ (VEC: VDMC: vdec=1:1:1) as electrolyte, button cells were assembled in an argon-protected glove box.

2. Testing the electrical performance of the button cell obtained in the step 1

2.1, the assembled button cell was tested for its first charge-discharge specific capacity of 0.1C at a constant temperature of 25 ℃ and a voltage of 2.8V-4.25V, and the first efficiency of the material was measured by using the ratio of the first discharge specific capacity to the charge specific capacity, and the obtained data are shown in table 2.

2.2 test of Normal temperature Direct Current Resistance (DCR), low temperature Direct Current Resistance (DCR)

And (3) under the constant temperature environment of 25 ℃, regulating the SOC of the lithium ion battery to be 50%, standing for 1 hour, and recording the voltage V0 after the standing is finished. Discharging for 10 seconds at a rate of 10C (current is I0), recording voltage V1 after the discharge is finished, and recording (V1-V0)/I0 as normal temperature DCR; and (3) under the constant temperature environment of 25 ℃, regulating the state of charge (SOC) of the lithium ion battery to 50%, regulating the temperature to-20 ℃, standing for 3 hours, and recording the voltage V2 after the standing is finished. The discharge was performed at a rate of 4C (current: I1) for 10 seconds, the voltage V3 after the end of the discharge was recorded, and (V3-V2)/I1 was recorded as a low-temperature DCR, and the obtained results are shown in Table 2.

TABLE 2

As can be seen from table 2, compared with comparative example 1, the porosity of the electrode sheet can be significantly improved by adding COFs or HOFs to the electrode sheet, thereby increasing the absorption capacity of the electrolyte, ensuring the electrolyte to be fully contacted with the electrode sheet, reducing the lithium ion transmission resistance and the electrode/electrolyte interface charge transfer resistance, accelerating the charge transfer efficiency and improving the rate capability. It can be seen from examples 1 and 2 that the fibrosis can increase the specific surface area of the electrode material, thereby increasing the capacity of the electrode and increasing the adhesive property. It can be seen from examples 1 and 9 that adding more COFs can increase the porosity but decrease the electrode material content and decrease the energy density.

On the other hand, as is clear from examples 1 and 3, as the COFs content increases, the porosity increases more and more, and the battery performance decreases, probably because the COFs content increases, the corresponding active material content decreases, the internal resistance increases, and the capacity decreases.

Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; while the invention has been described in detail with reference to the foregoing embodiments, it will be appreciated by those skilled in the art that variations may be made in the techniques described in the foregoing embodiments, or equivalents may be substituted for in part or in whole; such modifications and substitutions do not depart from the spirit of the invention.

Claims

1. The preparation method of the dry pole piece is characterized by comprising the following steps of:

B. granulating the fiberized material, then calendaring and forming to obtain a dry membrane, and attaching the dry membrane to at least one side of a current collector to obtain a dry pole piece.

2. The method of preparing according to claim 1, wherein the porous organic framework comprises at least one of a metal organic framework, a covalent organic framework, and a hydrogen bonding organic framework.

3. The method according to claim 1, wherein the porous organic framework has a specific surface area of 50m ² /g-6000m ² And/g, the pore diameter is 0.5nm-50nm.

4. The method according to claim 1, wherein in the step a, the fibrous material comprises 90 to 97 parts by weight of the electrode active material, 1 to 5 parts by weight of the conductive agent, 0.1 to 5 parts by weight of the porous organic frame, and 0.1 to 10 parts by weight of the binder.

5. The method according to any one of claims 1 to 4, wherein in step A, the mixing is performed at a rotational speed of 100rpm to 1000rpm for a period of 5min to 20min.

6. The method according to any one of claims 1 to 4, wherein in step A, the speed of the fiberizing treatment is 3000rpm to 20000rpm for 5min to 30min.

7. The method according to any one of claims 1 to 4, wherein in step B, the dry film with a predetermined thickness is obtained by one film formation or multiple film reduction by calender molding;

the primary film forming means that raw material particles enter a roller rotating in the same direction and are compacted, the density is continuously increased, the thickness is continuously reduced, and the dry film is obtained by discharging after the preset thickness is reached;

the repeated film reduction is to compact the raw material particles to prepare a semi-finished product of the dry film, and then to roll for multiple times by adjusting the distance between the two rollers to obtain the dry film with preset thickness.

8. The method according to any one of claims 1 to 4, wherein in step B, the bonding means comprises plate thermocompression bonding, preferably, the plate thermocompression bonding is performed at a temperature of 80 ℃ to 200 ℃ for a time of 5s to 60s.

9. A dry pole piece, characterized in that it is produced by the method of any one of claims 1-8.

10. A battery comprising the dry pole piece of claim 9.