CN112802987B - Method for preparing electrode slice by dry rolling - Google Patents

Abstract

The invention relates to the technical field of lithium ions, and discloses a method for preparing electrode sheets by dry rolling. The method includes: 1) passing the first film material and the foil material simultaneously between opposite first rollers, and by adding the first powder in the gap between the first film material and the foil material, performing first rolling, and A first powder sheeting layer is formed on one side of the foil material; 2) the first film material, the second film material and the above-mentioned foil material with the first powder sheeting layer formed pass through the opposite second roller at the same time; and by adding the second powder in the gap between the second film and the other side of the foil, and performing the second rolling to form a second powder sheet layer on the other side of the foil; 3) make The first film material and the second film material were separated from the side surfaces of the foil material, respectively, to obtain an electrode sheet. The method can realize double-sided simultaneous rolling and bonding of tablets, simplifies the process flow, reduces process equipment, and can continuously produce electrode tablets with uniform thickness.

Description

Method for preparing electrode sheet by dry rolling

technical field

The invention relates to the technical field of lithium ions, in particular to a method for preparing electrode sheets by dry rolling.

Background technique

In the automotive industry environment that uses traditional energy as power supply, the problem of environmental pollution has aroused people's attention to environmental protection and resource utilization.

Lithium-ion device technology is a key technology for the development of electric vehicles. Dry coating technology is one of the most advanced lithium-ion battery manufacturing technologies at present. Among them, dry rolling tableting process is the key to this process, and dry rolling tableting is the development direction of this process.

The existing dry rolling equipment has a complicated process. After the powder is rolled into the first stage, under the action of the roll gap, pressure and temperature, the tension of the produced sheet cannot be controlled. A series of process problems such as broken belt and particle loss, sticking to rollers and poor uniformity.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a method for preparing an electrode sheet by dry rolling in order to overcome the problems of tape breakage, particle drop, sticking to the roll, etc. existing in the dry rolling process in the prior art. The tableting method provided by the invention can realize the simultaneous rolling and bonding of tableting on both sides, simplify the technological process, reduce the technological equipment, and can continuously manufacture electrode sheets with uniform thickness.

In order to achieve the above purpose, the present invention provides a method for preparing an electrode sheet by dry rolling, the method comprising the following steps:

1) Make the first film material and the foil material pass between the opposite first rollers at the same time, and by adding the first powder in the gap between the first film material and the foil material, carry out the first rolling, in a A first powder tablet layer is formed on the side;

2) Make the first film material, the second film material and the above-mentioned foil formed with the first powder sheeting layer pass between the opposite second rollers at the same time, and pass through the other side of the second film material and the foil material. The second powder is added to the gap on the side, and the second rolling is performed to form a second powder sheet layer on the other side of the foil;

3) Separate the first film material and the second film material from the side surfaces of the foil material, respectively, to obtain an electrode sheet.

Preferably, in step 1), after the first rolling, the first film is separated from the foil by a guide roller.

Preferably, in step 1), the width of the first film material is smaller than the width of the foil material, more preferably the width of the first film material is 15%-90% of the width of the foil material.

Preferably, the width of the first roller is greater than or equal to the width of the first film material, and more preferably, the width of the first roller is 120%-160% of the width of the first film material.

Preferably, the foil is copper foil, aluminum foil, nickel foil, stainless steel foil or zinc foil.

Preferably, the thickness of the foil is 3-20 μm.

Preferably, in step 1), the particle size of the first powder is 0.5-20 μm.

Preferably, the curing temperature of the first powder is 40-100°C.

Preferably, the first powder is a mixture of active material, binder and conductive agent.

Preferably, the first powder is preheated to 40-100° C. before adding.

Preferably, the first powder is premixed and then added.

Preferably, in step 1), the working pressure of the first rolling is 30-75 T/cm ² .

Preferably, the working temperature of the first rolling is 90-180°C.

Preferably, the feeding speed of the foil is 1-50 m/min.

Preferably, the feeding speed of the first film material is 1-50 m/min.

Preferably, in step 2), the width of the second film material is smaller than the width of the foil material, more preferably the width of the second film material is 15%-90% of the width of the foil material.

Preferably, the width of the second roller is greater than or equal to the width of the second film material, more preferably the width of the second roller is 120%-160% of the width of the second film material.

Preferably, in step 2), the particle size of the second powder is 0.5-20 μm.

Preferably, the curing temperature of the second powder is 40-100°C.

Preferably, the second powder is a mixture of active material, binder and conductive agent.

Preferably, the second powder is preheated to 40-100° C. before adding.

Preferably, the second powder is added after premixing.

Preferably, in step 2), the working pressure of the second rolling is 30-75T/cm ² .

Preferably, the working temperature of the second rolling is 90-180°C.

Preferably, the feeding speed of the second film material is 1-50 m/min.

Preferably, the first film material is the same as the second film material.

Preferably, the film material is a heat-resistant film material, and the heat-resistant temperature is higher than 180°C.

Preferably, the film material is a PET, PI or PE film.

Preferably, the number of repetitions of the first rolling is one or more times.

Preferably, the number of repetitions of the second rolling is one or more times.

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

(1) The method provided by the present invention avoids the occurrence of uneven thickness and fragmentation and wrinkles caused by powder sticking to the roller, and can obtain continuous electrode sheets with uniform thickness;

(2) The method provided by the present invention can realize the simultaneous rolling and laminating of tablets on both sides, and the process flow is simplified and the process equipment is reduced by the one-time rolling tableting method.

Description of drawings

1 is a schematic flowchart of a method for preparing an electrode sheet by dry rolling provided by the present invention;

FIG. 2 is a step-by-step schematic diagram of a method for preparing an electrode sheet by dry rolling provided by the present invention;

FIG. 3 is a step-by-step schematic diagram of a method for preparing an electrode sheet by dry rolling provided by the present invention.

Description of reference numerals

11. The first membrane material 12. The second membrane material

2. Foil 21. One side of the foil

22. The other side of the foil

31. Vertical roller 1 32. Vertical roller 2

41. Horizontal roller 1 42. Horizontal roller 2

51. The first feeding bin 1 52. The second feeding bin 2

6. Guide roller 7. Electrode sheet

Detailed ways

The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, but not to limit the present invention.

The endpoints of ranges and any values disclosed herein are not limited to the precise ranges or values, which are to be understood to encompass values proximate to those ranges or values. For ranges of values, the endpoints of each range, the endpoints of each range and the individual point values, and the individual point values can be combined with each other to yield one or more new ranges of values that Ranges should be considered as specifically disclosed herein.

In the present invention, unless otherwise stated, the use of orientation words such as "up, down, left and right" generally refers to the upper, lower, left and right in the drawings, and "inside, outside" means Corresponds to the inside and outside of the structure.

FIG. 1 is a schematic flowchart of a method for preparing an electrode sheet by dry rolling provided by the present invention; FIG. 2 and FIG. 3 are a schematic step-by-step schematic diagram of a method for preparing an electrode sheet by dry rolling provided by the present invention. The preparation method of the present invention will be further described in detail below in conjunction with the accompanying drawings, wherein the same numerals in all the drawings represent the same features.

The invention provides a method for preparing an electrode sheet by dry rolling, and the method comprises the following steps:

1) Make the first film material 11 and the foil material 2 pass between the opposite first rollers 31, 32 at the same time, and add the first powder in the gap between the first film material 11 and the foil material 2, and perform the first roll Pressing to form a first powder pressing layer on one side 21 of the foil material 2;

2) Make the first film material 11, the second film material 12 and the above-mentioned foil material 2 formed with the first powder sheet layer pass simultaneously between the opposite second rollers 41, 42, and pass through the second film material 12 and the gap between the other side 22 of the foil material 2, add the second powder, carry out the second rolling, and form a second powder sheet layer on the other side 22 of the foil material 2;

3) Separate the first film material 11 and the second film material 12 from the side surfaces 21 and 22 of the foil material 2, respectively, to obtain electrode sheets.

The inventors of the present invention have found that, in dry rolling, by adding a film material between the contact surface of the powder to be pressed and the pressing roller, until the filming is completed, isolation rolling is performed by adding a film material to avoid rolling. The problem of sticking to the roller and thickness non-uniformity caused by the direct contact between the powder and the roller surface during the manufacturing process. Further, the inventor also found that the isolation roller pressing by the film material avoids the resulting sheet due to tension. Problems such as broken belts, dropped grains, etc.

Step 1) Make the first film material 11 and the foil material 2 pass between the opposite first rollers 31, 32 at the same time, and by adding the first powder in the gap between the first film material 11 and the foil material 2, the first step is carried out. Rolling to form a first powder sheet layer on one side 21 of the foil 2 .

In a preferred embodiment of the present invention, the first film material 11 and the foil material 2 pass between the opposing first rollers 31 and 32 at the same time, and pass through the first feeding bin 51 to the first film material 11 and the foil material 2 . The first powder is added in between, and after rolling, a first sheet pressing layer is formed on one side surface 21 of the foil material 2 , and the first film material is not separated from the foil material 2 . In this case, in the process of forming the second powder sheeting layer in step 2), the first film material 11 is formed on one side, and the foil material 2 and the second film material 12 with the first sheeting layer are formed on the other side. At the same time, the second powder is added between the opposite second rollers 41 and 42 and between the second film material 12 and the other side 22 of the foil material 2. A second powder tablet layer is formed on the other side 22 .

As another preferred embodiment of the present invention, as shown in FIG. 2 , the first film material 11 and the foil material 2 simultaneously pass between the opposing first rollers 31 and 32 , and pass through the first feeding bin 51 to the first The first powder is added between the film material 11 and the foil material 2, and after rolling, the first film material is separated from the foil material 2 by the guide roller 6, and a first sheet pressing layer is formed on one side of the foil material 2.

In the method of the present invention, preferably, the width of the first film material is smaller than the width of the foil material, more preferably the width of the first film material is 15%-90% of the width of the foil material, further preferably the width of the first film material is the width of the foil material The width of the first film is 30%-90% of the width of the foil, and more preferably the width of the first film is 45%-90% of the width of the foil. By arranging a film between the pressing roller and the foil, the contact between the powder and the pressing roller during the rolling process is avoided, thereby reducing the sticking to the roller and the uneven thickness caused by the direct contact between the powder and the roller surface, and further ensuring the production of Tabletting continuity and stability.

In the method of the present invention, preferably, the width of the first roller is greater than or equal to the width of the first film material, more preferably the width of the first roller is 120%-160% of the width of the first film material, further preferably The width of one roller is 130%-160% of the width of the first film material, and more preferably the width of the first roller is 140%-160% of the width of the first film material. By setting the width of the pressing roller to be wider than the width of the film, it is further ensured that the pressing roller does not contact the powder during the rolling process, thereby ensuring the continuity and stability of the pressed sheet.

In the method of the present invention, preferably, the film material is a heat-resistant film material, and the heat-resistant temperature is higher than 180°C, more preferably 180-210°C.

In the method of the present invention, preferably, the first film material is a PET, PI or PE film. In a specific embodiment of the invention, the first film material is a PET film.

For the above-mentioned foils, those skilled in the art can make specific selections as required. In the method of the present invention, the foil material is copper foil, aluminum foil, nickel foil, stainless steel foil or zinc foil.

The thickness of the above-mentioned foil can be, for example, 3-20 μm, and in the method of the present invention, preferably, the thickness of the foil is 5-14 μm. In a specific aspect of the present invention, an aluminum foil having a thickness of 14 μm is used.

In the method of the present invention, preferably, the particle size of the first powder is 0.5-20 μm, more preferably 7-13 μm. By controlling the particle size of the powder, the damage to the foil or film due to the excessively large particles during the rolling process is avoided, and the thickness of the obtained tablet is guaranteed to be uniform.

In the present invention, the powder is battery mixed powder, including active material, binder and conductive agent. In the method of the present invention, preferably, the first powder is a mixture of active material, binder and conductive agent. Wherein, the active material can be transition metal oxide type positive electrode material, polyanion type positive electrode material or polymer positive electrode material; the conductive agent can be selected from acetylene black, carbon fiber, carbon nanotube, Ketjen black, conductive graphite, graphene and activated carbon One or more of; the binder can be selected from sodium carboxymethyl cellulose, styrene-butadiene rubber, polyvinylidene fluoride, polytetrafluoroethylene, polyacrylic acid, polyacrylonitrile, sodium alginate, chitosan, polyvinylidene fluoride One or more of vinyl alcohol, polybutyl acrylate and polyethylene oxide.

The weight ratio of the above active material, binder and conductive agent is (70-90):(5-10):(3-10). In a specific embodiment of the present invention, the first powder is a mixture of high nickel ternary positive electrode material, sodium carboxymethyl cellulose and Ketjen black in a weight ratio of 85:7:8.

In the inventive method, the curing temperature of the first powder may be 40-100°C, preferably 40-60°C.

In the method of the invention, preferably, the first powder is preheated to 40-100°C, more preferably 40-60°C, and then added. By preheating the powder, it is further ensured that during the rolling process, the powder solidifies to form a tablet layer.

In the method of the present invention, preferably, the method further comprises: premixing the first powder before adding. In a specific embodiment of the present invention, the first powder is stirred until it becomes fibrillated (the cotton ball is fluffy) and then added.

In the method of the present invention, preferably, the working pressure of the first rolling is 30-75 T/cm ² , more preferably 40-55 T/cm ² . In addition, the working temperature of the first rolling is preferably 90-180°C, more preferably 130-160°C.

In the method of the present invention, preferably, the feeding speed of the foil is 1-50 m/min, more preferably 1-10 m/min, further preferably 1-5 m/min.

In the method of the present invention, preferably, the feeding speed of the first film material 11 is 1-50 m/min, more preferably 1-5 m/min, further preferably 1-3 m/min.

The feeding speed of the first film material may be the same as or different from the feeding speed of the foil material. Considering the cost of the film material, preferably, the feeding speed of the film material is lower than the feeding speed of the foil material. In a specific embodiment of the present invention, the feeding speed of the foil material is 5 m/min, and the feeding speed of the first film material is 3 m/min.

In the above-mentioned first rolling process, repeated rolling may be performed as required. In the method of the present invention, the number of repetitions of the first rolling is one or more times, preferably 1-2 times.

Next, with reference to FIG. 3 , the above-mentioned step 2 will be described in detail.

Step 2) Make the first film material 11, the second film material 12 and the above-mentioned foil material 2 formed with the first powder sheet layer pass simultaneously between the opposite second rollers 41, 42, and pass through the second film A second powder is added to the gap between the material 12 and the other side 22 of the foil 2, and a second rolling is performed to form a second powder sheet layer on the other side 22 of the foil 2.

FIG. 3 is a step-by-step schematic diagram of a method for preparing an electrode sheet by dry rolling. The first film material 11, the second film material 12 and the foil 2 formed with the first powder sheet layer pass simultaneously between the opposite second rollers 41, 42, and pass through the contact between the second film material 12 and the foil material 2. A second powder material is added between the other side surfaces 22 , and after the second rolling, the second film material is separated from the foil material 2 , and a second powder material sheet layer is formed on the other side surface 22 of the foil material 2 .

In the method of the present invention, preferably, the width of the second film material is smaller than the width of the foil material, more preferably the width of the second film material is 15%-90% of the width of the foil material, further preferably the width of the second film material is the width of the foil material The width of the second film is 30%-90% of the width of the foil, and more preferably the width of the second film is 45%-90% of the width of the foil. By arranging the second film material between the pressing roller and the foil, the contact between the powder and the pressing roller during the rolling process is avoided, thereby reducing the problems of sticking to the roller and thickness unevenness caused by the direct contact between the powder and the roller surface, and further To ensure the continuity and stability of the tablet.

In the method of the present invention, preferably, the width of the second roller is greater than or equal to the width of the second film material, more preferably the width of the second roller is 120%-160% of the width of the second film material, further preferably The width of the second roller is 130%-160% of the width of the second film material, and more preferably the width of the second roller is 140%-160% of the width of the second film material. By setting the width of the pressing roller to be wider than the width of the film, it is further ensured that the pressing roller does not contact the powder during the rolling process, thereby ensuring the continuity and stability of the pressed sheet.

In the method of the present invention, preferably, the film material is a heat-resistant film material, and the heat-resistant temperature is preferably higher than 180°C, more preferably 180-210°C.

In the method of the present invention, preferably, the film material is a PET, PI or PE film. In a specific embodiment of the invention, the second film material and the first film material are both PET films.

In the method of the present invention, preferably, the particle size of the second powder is 0.5-20 μm, more preferably 7-13 μm. By controlling the particle size of the powder, the damage to the foil or film due to the excessively large particles during the rolling process is avoided, and the thickness of the obtained tablet is guaranteed to be uniform.

In the present invention, the powder is battery mixed powder, including active material, binder and conductive agent. In the method of the present invention, preferably, the second powder is a mixture of active material, binder and conductive agent. Wherein, the active material can be transition metal oxide type positive electrode material, polyanion type positive electrode material or polymer positive electrode material; the conductive agent can be selected from acetylene black, carbon fiber, carbon nanotube, Ketjen black, conductive graphite, graphene and activated carbon One or more of; the binder can be selected from sodium carboxymethyl cellulose, styrene-butadiene rubber, polyvinylidene fluoride, polytetrafluoroethylene, polyacrylic acid, polyacrylonitrile, sodium alginate, chitosan, polyvinylidene fluoride One or more of vinyl alcohol, polybutyl acrylate and polyethylene oxide.

The weight ratio of the above active material, binder and conductive agent is (70-90):(5-10):(3-10). In a specific embodiment of the invention, the second powder is the same as the first powder.

In the inventive method, the curing temperature of the second powder may be 40-100°C, preferably 40-60°C.

In the inventive method, preferably, the second powder is preheated to 40-100° C. before adding. By preheating the powder, it is further ensured that during the rolling process, the powder solidifies to form a tablet layer.

In the method of the present invention, preferably, the method further comprises: premixing the second powder before adding. In a specific embodiment of the present invention, the addition is carried out by stirring the second powder until fiberization.

In the method of the present invention, preferably, the working pressure of the second rolling is 30-75 T/cm ² , more preferably 40-55 T/cm ² . In addition, the working temperature of the second rolling is preferably 90-180°C, more preferably 150-180°C.

In the method of the present invention, preferably, the feeding speed of the second membrane material 12 is 1-50 m/min, more preferably 1-5 m/min, further preferably 1-3 m/min.

The feeding speed of the second film material may be the same as or different from the feeding speed of the foil material. In consideration of the cost of the film material, the feeding speed of the film material is preferably lower than the feeding speed of the foil material. In a specific embodiment of the present invention, the feeding speed of the foil material is 5 m/min, and the feeding speed of the second film material is 3 m/min.

In the above-mentioned second rolling process, repeated rolling can be performed as required. In the method of the present invention, the number of repetitions of the second rolling is 1 or more times, preferably 1-2 times.

In the above step 1) forming a first powder sheeting layer on one side of the foil, and in step 2) forming a second powder sheeting layer on the other side of the foil, the film is separated from the foil to obtain electrode pads.

In a preferred embodiment of the present invention, the first film material 11 and the foil material 2 pass between the opposing first rollers 31 and 32 at the same time, and pass through the first feeding bin 51 to the first film material 11 and the foil material 2 . The first powder is added in between, and after rolling, a first sheet pressing layer is formed on one side surface 21 of the foil material 2 , and the first film material is not separated from the foil material 2 . In the process of forming the second powder sheeting layer, the foil material 2 with the first film material 11 on one side and the first sheeting layer on the other side and the second film material 12 pass through the opposite second roller at the same time 41, 42, and add the second powder between the second film 12 and the other side 22 of the foil 2, and after the second rolling, a second powder is formed on the other side 22 of the foil 2. For the powder tablet layer, at this time, the first film material 11 and the second film material 12 are separated from the side surfaces of the foil material, respectively, to obtain an electrode sheet.

In another preferred embodiment of the present invention, the first film material 11 and the foil material 2 pass between the opposing first rollers 31 and 32 at the same time, and pass through the first feeding bin 51 to the first film material 11 and the foil material. The first powder is added between the materials 2, and after rolling, a first sheet pressing layer is formed on one side surface 21 of the foil material 2, and the first film material is separated from the foil material 2 by the guide roller 6. In the process of forming the second powder sheeting layer, the first film material 11, the foil material 2 with the first sheeting layer formed on the other side and the second film material 12 pass through the opposite second roller 41 at the same time, 42, and the second powder is added between the second film 12 and the other side 22 of the foil 2, and after the second rolling, the second powder is formed on the other side 22 of the foil 2 Sheeting layer, at this time, the first film material 11 and the second film material 12 are separated from the side surfaces of the foil material, respectively, to obtain an electrode sheet.

Example 1

With reference to FIG. 1 , this embodiment is used to illustrate the method for preparing an electrode sheet by dry rolling of the present invention.

The first powder used in this example 1 is the same as the second powder, which is a mixture of high nickel ternary positive electrode material, sodium carboxymethyl cellulose and Ketjen black (high nickel ternary positive electrode material, carboxymethyl fiber The weight ratio of plain sodium and Ketjen black is 85:7:8), and the average particle size is 10 μm. It is pre-mixed to fibrillation and added to the feeding bin; the first film material and the second film material are both PET film, foil The material is aluminum foil with a thickness of 14 μm.

The specific preparation method is:

(1) The first film material 11 (3m/min) and the foil material (5m/min) are unwound, and at the same time pass vertically between the opposite first rollers (specifically, the vertical rollers 31, 32), and pass through the first feeding bin 51 Add the first powder to the gap between the first film material and the foil material at a feeding speed of 400 g/min, and perform the first rolling at 50 T/cm ² and 150 ° C to form the first powder on one side 21 of the foil material 2. A powder sheeting layer, the rolled first film material 11 continues to be wound to the next roller surface through the guide roller 6 until the film is wound up. At this time, the first powder pressing layer formed by rolling the powder through the first pass is attached to one side 21 of the foil to form a single-layer electrode sheet.

The width of the foil material 2 is 300 mm, the width of the first film material 11 is 220 mm, and the width of the vertical roller is 350 mm.

(2) The second film material 12 (3m/min) and the above-mentioned single-layer electrode sheet (5m/min) continue to be unwound, and at the same time pass vertically between the opposite second rollers (specifically, the horizontal rollers 41, 42), and pass through The second feeding bin 52 feeds the second powder into the gap between the second film and the other side of the foil at a feeding speed of 400 g/min, and performs second rolling at 50 T/cm ² and 150° C. A second powder tablet layer is formed on the other side 22 of the 2. At this time, the second powder pressing layer formed by the second rolling of the powder is laminated on the other side 21 of the foil 2 to form a double-layered electrode sheet 7 .

(3) The first film material 11 , the second film material 12 and the electrode sheet are respectively wound up.

The electrode sheet prepared above has certain hardness and flexibility. During the preparation process, there is no occurrence of band breakage, and continuous preparation can be realized.

Comparative Example 1

The same conditions as in Example 1 were carried out, except that during the rolling process, only the foil was fed, and the first and second films were not fed, that is, during the rolling process, the pressure roller It is directly contacted with the powder and rolled to obtain a double-layer electrode sheet.

During the above preparation process, the phenomenon of tape breaking and particle dropping occurred, and it was observed that the powder adhered to the surface of the pressing roller, which affected the continuous production of the electrode sheet.

The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above-mentioned embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, These simple modifications belong to the protection scope of the present invention.

In addition, it should be noted that each specific technical feature described in the above-mentioned specific implementation manner may be combined in any suitable manner under the circumstance that there is no contradiction. In order to avoid unnecessary repetition, the present invention will not describe various possible combinations.

In addition, the various embodiments of the present invention can also be combined arbitrarily, as long as they do not violate the spirit of the present invention, they should also be regarded as the contents disclosed in the present invention.

Claims (32)

1. The method for preparing the electrode plate by dry rolling is characterized by comprising the following steps:

1) simultaneously passing the first film (11) and the foil (2) between opposite first rollers (31, 32), and performing first rolling by adding first powder into a gap between the first film (11) and the foil (2) to form a first powder laminated layer on one side surface (21) of the foil (2);

2) passing the first film (11), the second film (12) and the foil (2) with the first powder laminated layer formed thereon through the opposite second rollers (41, 42), and adding a second powder into a gap between the second film (12) and the other side surface (22) of the foil (2) to perform a second rolling to form a second powder laminated layer on the other side surface (22) of the foil (2);

3) separating the first film material (11) and the second film material (12) from the side surfaces (21, 22) of the foil (2) respectively to obtain electrode plates,

wherein, the first powder is a mixture of an active substance, a binder and a conductive agent;

the second powder is a mixture of an active substance, a binder and a conductive agent.

2. The method for manufacturing an electrode sheet by dry rolling according to claim 1, wherein in step 1), after the first rolling, the first film is separated from the foil (2) by a guide roller (6).

3. The method for preparing the electrode sheet by dry rolling according to claim 1, wherein in step 1), the width of the first film is smaller than that of the foil.

4. The method for preparing the electrode sheet by dry rolling according to claim 3, wherein in the step 1), the width of the first film is 15-90% of the width of the foil.

5. The method for preparing the electrode sheet by dry rolling according to claim 1, wherein in the step 1), the width of the first roller is greater than or equal to the width of the first film.

6. The method for preparing the electrode sheet by dry rolling according to claim 5, wherein in the step 1), the width of the first roller is 120-160% of the width of the first film.

7. The method for preparing an electrode sheet by dry rolling according to claim 1, wherein the foil is a copper foil, an aluminum foil, a nickel foil, a stainless steel foil or a zinc foil.

8. The method for preparing an electrode sheet by dry rolling according to claim 7, wherein the foil has a thickness of 3-20 μm.

9. The method for preparing the electrode sheet by dry rolling according to claim 1, wherein in the step 1), the particle size of the first powder is 0.5-20 μm.

10. The method for preparing the electrode sheet by dry rolling according to claim 1, wherein in the step 1), the curing temperature of the first powder is 40-100 ℃.

11. The method for preparing the electrode sheet by dry rolling according to claim 1, wherein in the step 1), the first powder is preheated to 40-100 ℃ and then added.

12. The method for preparing the electrode sheet by dry rolling according to claim 1, wherein in the step 1), the first powder is premixed and then added.

13. The method for preparing the electrode sheet by dry rolling according to claim 1, wherein in the step 1), the working pressure of the first rolling is 30-75T/cm²。

14. The method for preparing the electrode sheet by dry rolling according to claim 1, wherein the working temperature of the first rolling in step 1) is 90-180 ℃.

15. The method for preparing an electrode sheet by dry rolling according to claim 1, wherein in step 1), the feeding speed of the foil (2) is 1-50 m/min.

16. The method for preparing the electrode sheet by dry rolling according to claim 1, wherein in the step 1), the feeding speed of the first film material (11) is 1-50 m/min.

17. The method for preparing the electrode sheet by dry rolling according to claim 1, wherein in the step 2), the width of the second film is smaller than that of the foil.

18. The method for preparing the electrode sheet by dry rolling according to claim 17, wherein in the step 2), the width of the second film is 15-90% of the width of the foil.

19. The method for preparing the electrode sheet by dry rolling according to claim 1, wherein in the step 2), the width of the second roller is greater than or equal to the width of the second film.

20. The method for preparing the electrode sheet by dry rolling according to claim 19, wherein in the step 2), the width of the second roller is 120-160% of the width of the second film.

21. The method for preparing the electrode sheet by dry rolling according to claim 1, wherein in the step 2), the particle size of the second powder is 0.5-20 μm.

22. The method for preparing the electrode sheet by dry rolling according to claim 1, wherein the curing temperature of the second powder in the step 2) is 40-100 ℃.

23. The method for preparing the electrode sheet by dry rolling according to claim 1, wherein in the step 2), the second powder is preheated to 40-100 ℃ and then added.

24. The method for preparing the electrode sheet by dry rolling according to claim 1, wherein in the step 2), the second powder is premixed and then added.

25. The method for preparing an electrode sheet by dry rolling according to claim 1, wherein in the step 2), the working pressure of the second rolling is 30-75T/cm²。

26. The method for preparing the electrode sheet by dry rolling according to claim 1, wherein the second rolling has a working temperature of 90-180 ℃ in step 2).

27. The method for preparing the electrode sheet by dry rolling according to claim 1, wherein in the step 2), the feeding speed of the second film material (12) is 1-50 m/min.

28. The method for preparing the electrode sheet by dry rolling according to any one of claims 1 to 27, wherein the first film material is the same as the second film material.

29. The method for preparing the electrode sheet by dry rolling according to any one of claims 1 to 27, wherein in the step 2), the first film material and the second film material are heat-resistant film materials, and the heat-resistant temperature is higher than 180 ℃.

30. The method for preparing an electrode sheet by dry rolling according to claim 29, wherein in the step 2), the first film material and the second film material are PET, PI or PE films.

31. The method for producing an electrode sheet by dry rolling according to any one of claims 1 to 27, wherein the number of repetitions of the first rolling is 1 or more.

32. The method for producing an electrode sheet by dry rolling according to any one of claims 1 to 27, wherein the second rolling is repeated 1 or more times.

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