Dry-method electrode and preparation method and application thereof

Abstract

The invention relates to a dry electrode as well as a preparation method and application thereof, and relates to the technical field of lithium ion batteries. Comprising the following steps: under the conditions that the surface roughness of the inner wall of a wire drawing machine is Ra 6.3 [mu] m to Ra 0.025 [mu] m, the gas pressure during wire drawing treatment is 0.3-2.0 MPa, the feeding speed is 30-500 g / min, and the outlet radius is 2.0-4.0 cm, performing wire drawing treatment on a uniformly mixed material to obtain a flocculent material; the mixed material comprises an active material, a conductive agent and a binder; performing film pressing treatment on the flocculent material to obtain an electrode film; and preparing the electrode film into an electrode. The binder is high in wiredrawing degree and controllable, the film forming quality is effectively improved, the defects of an electrode film are reduced, and batch continuous production can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium ion batteries, and in particular to a dry electrode and a preparation method and application thereof. Background Art

[0002] Lithium-ion batteries are one of the energy storage technologies in the fields of power, consumer electronics, energy storage, etc. With the global energy shortage and the improvement of environmental protection awareness, the new energy industry has become an important development direction in my country. Lithium-ion batteries have become the leader in the new energy industry due to their advantages such as high operating voltage, no memory effect, low self-discharge and long cycle life. With the increasing demand for the application of lithium-ion batteries, the requirements for lithium-ion batteries in terms of high energy density and high safety are gradually increasing, and the cost of manufacturing them is also increasing.

[0003] At present, the domestic production of battery electrodes mainly uses the wet process, which requires the use of organic solvents. This solvent needs to be baked out later, which consumes a lot of energy, occupies a large area of ​​drying equipment, and it is difficult to completely remove the solvent, so it is easy to cause a series of problems such as gas production in the subsequent battery application. The dry production process does not add any organic solvents or water during the production process, so there is no need for baking, and no emissions are generated. It is an ideal electrode production process.

[0004] At present, the dry-process electrode preparation process generally relies on the shear force of the airflow to draw and fiberize the binder. The main control point is whether the binder can be completely fiberized. However, under the process conditions of airflow crushing, the fiberization time is short, the fiberization degree is uncontrollable, and the fiberization degree of the binder is insufficient, which easily causes many defects in the electrode film. The strong fiberization degree easily leads to the breakage of the binder chain. The tensile strength of the electrode after film formation is poor. The above problems have brought difficulties to continuous production. The patent with publication number CN108735528A discloses a method for preparing a dry-process electrode, but this method still requires solvent for coating after mixing, and does not fundamentally remove the influence of organic solvents; the patent with publication number CN105225847A discloses a method for preparing a dry-process electrode, but this method requires shear deformation mixing under the action of a shearing machine heated at about 80℃~120℃. This method consumes a lot of energy, has a complex process, and is difficult to control. In view of this, the present invention provides a dry electrode and its preparation method and application. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a dry electrode and a preparation method and application thereof, with the purpose of effectively controlling the fiberization degree of the binder.

[0006] The technical solution of the present invention to solve the above technical problems is as follows: In a first aspect, a method for preparing a dry electrode comprises the following steps: subjecting a mixed material to wire drawing to obtain a flocculent material under the conditions that the surface roughness of the inner wall of a wire drawing machine is Ra 6.3 μm to Ra 0.025 μm, the gas pressure during wire drawing is 0.3 MPa to 2.0 MPa, the feed rate is 30 g / min to 500 g / min, and the outlet radius is 2.0 cm to 4.0 cm; the mixed material comprises an active material, a conductive agent, and a binder; The flocculent material is subjected to a film pressing process to obtain an electrode film; and the electrode film is prepared into an electrode.

[0007] The beneficial effects of the present invention are: (1) The binder of the present invention has a high and controllable degree of wire drawing, which effectively improves the quality of film formation, reduces the defects of the electrode film, and can realize batch continuous production.

[0008] (2) Except for the wire drawing process, the other processing of the present invention adopts the mature technology and equipment in the current industry, without increasing the investment in other equipment, and can be produced without basically increasing the cost, thereby enhancing the competitiveness of the product; and the electrode production process does not require any solvent, which can achieve zero pollution.

[0009] (3) The process of the present invention is simple, fast, easy to operate, has low requirements on equipment during the production process, and is convenient for actual production operation.

[0010] Based on the above technical solution, the present invention can also be improved as follows.

[0011] Furthermore, under the conditions that the inner wall surface roughness during wire drawing is Ra 6.3μm~Ra 0.1μm, the gas pressure during wire drawing is 0.5 MPa~1.0 MPa, the feed rate is 100 g / min~300 g / min, and the outlet radius is 2.5 cm~3.0 cm, the mixed material is subjected to wire drawing to obtain a flocculent material.

[0012] The beneficial effect of adopting the above further scheme is that by adjusting the appropriate inner wall roughness, the degree of binder fiberization can be effectively adjusted to an optimal state to ensure that the subsequent electrode membrane has good flexibility and tensile strength.

[0013] Furthermore, the binder includes at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylic acid (PAA), polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), and carboxymethyl cellulose (CMC).

[0014] The beneficial effect of adopting the above further scheme is that the binder system adopted by the present invention is more mature and has been verified many times in lithium battery systems. At the same time, compared with other binders, the above binder system can be better applied to dry system.

[0015] Further, the active material includes any one of a positive electrode active material and a negative electrode active material; And / or, the conductive agent includes at least one of metal powder, acetylene black, Ketjen black, furnace black, conductive carbon black, conductive graphite, carbon nanotubes, carbon fiber, and graphene.

[0016] The beneficial effect of adopting the above further solution is that the conductive agent used in the present invention is low-priced and easily available.

[0017] Further, the positive electrode active material includes at least one of lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, ternary nickel cobalt manganese lithium, nickel cobalt aluminum manganese lithium, sodium iron phosphate, sodium cobalt oxide, and sodium manganese oxide; And / or, the negative electrode active material includes at least one of hard carbon, soft carbon, artificial graphite, natural graphite, mesocarbon microbeads (MCMB), lithium titanate, and activated carbon.

[0018] The beneficial effect of adopting the above further solution is that the negative electrode material adopted by the present invention is low-priced and easily available.

[0019] Furthermore, the mass ratio of the active material, the conductive agent and the binder is 80:10:10 to 95:2.5:2.5.

[0020] Furthermore, the mixed material is mixed before the wire drawing process, and the mixing parameters are: a rotation speed of 100 r / min to 1500 r / min and a time of 0.5 h to 8 h.

[0021] The beneficial effect of adopting the above further scheme is that the present invention can ensure that the powder is mixed evenly, providing a good foundation for subsequent production.

[0022] Further, the flocculent material is subjected to a film pressing process, comprising the following specific steps: the flocculent material is subjected to a film pressing process using a rolling roller, the rolling temperature is 80° C. to 250° C., and the rolling speed is ≤20 m / min; And / or, preparing the electrode film into an electrode comprises the following specific steps: compounding the electrode film and the metal current collector by a rolling roller, the compounding temperature is 80° C. to 250° C., and the compounding speed is ≤40 m / min, to obtain a battery electrode.

[0023] The beneficial effect of adopting the above further scheme is that the present invention can obtain a battery pole piece with good bonding state between the electrode film and the metal current collector, effectively improving the cycle stability of the battery.

[0024] In a second aspect, a dry electrode is provided, wherein the dry electrode is prepared by the preparation method.

[0025] A third aspect is an application of a dry electrode, wherein the dry electrode is used in the preparation of a lithium-ion battery.

[0026] The beneficial effect of adopting the above scheme is that the dry process can effectively improve the life of lithium-ion batteries compared with the wet process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The figure is a comparison of the tensile strength of electrode films prepared by different drawing parameters in various examples of the present invention.

[0028] Figure 2 This is a SEM image of the material after wire drawing according to Example 1 of the present invention.

[0029] Figure 3 This is a SEM image of the surface of the battery electrode prepared in Example 2 of the present invention.

[0030] Figure 4 This is the electrode product prepared in Example 4 of the present invention.

[0031] Figure 5 The test performance results of the battery assembled with the pole pieces prepared by the present invention. DETAILED DESCRIPTION

[0032] The principles and features of the present invention are described below, and the examples are only used to explain the present invention and are not used to limit the scope of the present invention. If no specific technology or conditions are specified in the embodiments, the technology or conditions described in the literature in this field or the product instructions are used. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased through regular channels.

[0033] Based on the original air flow shearing process, the present invention adds a grinding bed to the wire drawing machine equipment and changes the roughness to effectively control the degree of binder fiberization. Its main principle is to ensure that the added binder can be completely drawn and maintained in the optimal state, and at the same time, it is evenly mixed with the active material, which can significantly improve the uniformity and consistency of the material, and the prepared battery pole piece has fewer defects and high tensile strength. The method is simple and effective.

[0034] The present invention mainly ensures the degree of wire drawing of the adhesive particles from two aspects. First, the large surface area inside the wire drawing machine can greatly increase the contact probability between the particles (such as adhesive) and the inner wall of the wire drawing machine, including the contact area and contact time, so as to ensure that all the particles entering the wire drawing machine can be deformed by wire drawing. Secondly, a swirling airflow will be formed inside the wire drawing machine, and the particles and other materials will form a circular motion inside the wire drawing machine with the swirling airflow. The particles that have just entered the wire drawing machine will be concentrated at the edge of the wire drawing machine under the action of a large centrifugal force. The centrifugal force of the material after wire drawing is reduced, and it leaves the wire drawing machine through the outlet with the airflow. Specifically, by controlling the surface roughness of the inner wall of the wire drawing machine, the airflow pressure, and the outlet radius parameters, the wire drawing effect of the particles can be accurately controlled. After the wire drawing is complete, the active substance and the conductive agent powder will be connected to each other through point contact, and the wires will be connected to form a network structure to fix other materials. It is then rolled by a hot roller, and after rolling and forming, it is compounded onto the current collector by a hot roller to form a battery electrode for high-performance and high-capacity lithium-ion batteries with high compaction density and good surface uniformity.

[0035] The present embodiment involves a method for preparing a dry electrode, comprising the following steps: the surface roughness of the inner wall of a wire drawing machine is Ra 6.3 μm~Ra 0.025 μm, for example, Ra 6.3 μm, Ra 5 μm, Ra 4 μm, Ra 3 μm, Ra 1 μm, Ra 0.8 μm, Ra 0.5 μm, Ra 0.1 μm, Ra 0.025 μm, etc., the gas pressure during wire drawing is 0.3 MPa~2.0 MPa, for example, 0.3 MPa, 0.5 MPa, 1 MPa, 2.0 MPa, etc., the feed rate is 30 g / min~500 g / min, for example, 30 g / min, 100 g / min, 150 g / min, 500 g / min, etc., and the outlet radius is 2.0 cm~4.0 cm, for example, 2.0 cm, 2.5 cm, 4.0 cm, 4.0 cm cm, etc., and the mixed material is subjected to wire drawing to obtain a flocculent material; the mixed material includes an active material, a conductive agent and a binder; The flocculent material is subjected to a film pressing process to obtain an electrode film; and the electrode film is prepared into an electrode.

[0036] In this embodiment, the binder preferably includes at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylic acid (PAA), polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), and carboxymethyl cellulose (CMC).

[0037] Preferably, in this embodiment, the active material includes any one of a positive electrode active material and a negative electrode active material; for example, the positive electrode active material includes at least one of lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, ternary nickel cobalt manganese lithium, nickel cobalt aluminum manganese lithium, sodium iron phosphate, sodium cobalt oxide, and sodium manganese oxide; the negative electrode active material includes at least one of hard carbon, soft carbon, artificial graphite, natural graphite, mesophase carbon microbeads (MCMB), lithium titanate, and activated carbon.

[0038] And / or, the conductive agent includes at least one of metal powder (such as gold powder, silver powder, etc.), acetylene black, Ketjen black, furnace black, conductive carbon black, conductive graphite, carbon nanotubes, carbon fiber, and graphene.

[0039] Preferably, in this embodiment, the mass ratio of the active material, the conductive agent and the binder is 80:10:10-95:2.5:2.5, for example, 80:10:10, 85:7.5:7.5, 90:5:5, 95:2.5:2.5 and the like.

[0040] Preferably, in this embodiment, the mixed material is mixed before the wire drawing process, and the mixing parameters are: a rotation speed of 100 r / min~1500 r / min, for example, 100 r / min, 500 r / min, 1000 r / min, 1500 r / min, etc., and a time of 0.5 h~8 h, for example, 0.5 h, 2 h, 4 h, 8 h, etc.

[0041] In this embodiment, the flocculent material is subjected to a film pressing process, which comprises the following specific steps: the flocculent material is subjected to a film pressing process using a rolling roller, the rolling temperature is 80°C to 250°C, such as 80°C, 100°C, 200°C, 250°C, etc., the rolling speed is ≤20 m / min, such as 20 m / min, 15 m / min, 10 m / min, etc.; the rolling thickness is 150±2 μm; And / or, preparing the electrode film into an electrode comprises the following specific steps: compounding the electrode film and the metal current collector by using a rolling roller, the compounding temperature is 80°C~250°C, for example, 80°C, 100°C, 200°C, 250°C, etc., and the compounding speed is ≤40 m / min, for example, 35 m / min, 20 m / min, 15 m / min, 10 m / min, etc., to obtain a battery electrode sheet.

[0042] This embodiment also relates to a dry electrode, which is prepared by the preparation method described above.

[0043] This embodiment also relates to an application of a dry electrode, and the dry electrode is used in the preparation of a lithium-ion battery.

[0044] The invention is further described below with reference to specific embodiments.

[0045] Embodiment 1: (1) Preparation of positive electrode: This embodiment relates to a method for preparing a dry positive electrode, comprising the following steps: Step 1: Add the raw materials lithium cobalt oxide, conductive agent conductive carbon black, and binder polytetrafluoroethylene (PTFE) into the powder mixer in a ratio of 80:10:10. Mix the powder for 2 hours. After mixing, take the mixed powder out of the powder mixer.

[0046] Step 2: Add the dry powder material in step 1 to the wire drawing machine. The inner wall roughness of the wire drawing machine is selected to be Ra 0.1 μm, and the wire drawing air flow pressure is adjusted to 1.0 MPa, the feed rate is 150 g / min, and the outlet radius is adjusted to 2.5 cm. The dry powder will form a flocculent material after being fully drawn by the wire drawing machine.

[0047] Step 3: The flocculent material obtained in step 2 is pressed into film using a high-temperature roller with a pressing temperature of 120°C, a pressing speed of 18m / min, and a pressing thickness of 150±2μm to obtain an electrode film with good uniformity, which is Example 1.

[0048] Step 4: The electrode film prepared in step 3 is compounded with a metal current collector through a high-temperature rolling machine at a rolling temperature of 120°C and a rolling speed of 12m / min to produce a sandwich-structured battery electrode.

[0049] (2) Preparation of negative electrode: This embodiment relates to a method for preparing a dry negative electrode. Compared with the method for preparing a dry positive electrode in this embodiment, lithium cobalt oxide is replaced by graphite, and the rest is the same.

[0050] Embodiment 2: (1) Preparation of positive electrode: This embodiment relates to a method for preparing a dry positive electrode, comprising the following steps: Step 1: Add the raw materials lithium cobalt oxide, conductive agent conductive carbon black, and binder polytetrafluoroethylene (PTFE) into the powder mixer in a ratio of 80:10:10. Mix the powder for 2 hours. After mixing, take the mixed powder out of the powder mixer.

[0051] Step 2: Add the dry powder material in step 1 to the wire drawing machine. The inner wall roughness of the wire drawing machine is selected to be Ra 0.8 μm, and the wire drawing air flow pressure is adjusted to 1.0 MPa, the feed rate is 150 g / min, and the outlet radius is adjusted to 2.5 cm. The dry powder will form a flocculent material after being fully drawn by the wire drawing machine.

[0052] Step 3: The flocculent material obtained in step 2 is pressed into film using a high-temperature roller with a pressing temperature of 120°C, a pressing speed of 18m / min, and a pressing thickness of 150±2μm to obtain an electrode film with good uniformity, which is Example 2.

[0053] Step 4: The electrode film prepared in step 3 is compounded with the metal current collector by a high-temperature rolling machine. The rolling temperature is 120°C and the rolling speed is 12m / min. Then, a sandwich-structured battery electrode can be produced ( Figure 4 ).

[0054] (2) Preparation of negative electrode: This embodiment relates to a method for preparing a dry negative electrode. Compared with the method for preparing a dry positive electrode in this embodiment, lithium cobalt oxide is replaced by graphite, and the rest is the same.

[0055] Embodiment three: (1) Preparation of positive electrode: This embodiment relates to a method for preparing a dry positive electrode, comprising the following steps: Step 1: Add the raw materials of ternary nickel-cobalt-manganese 523 material, conductive agent conductive carbon black, and binder polytetrafluoroethylene (PTFE) into the powder mixer in the ratio of 80:10:10. The mixing time is 2 hours. After the mixing is completed, take the mixed powder out of the powder mixer.

[0056] Step 2: Add the dry powder material in step 1 to the wire drawing machine. The inner wall roughness of the wire drawing machine is selected to be Ra 0.8μm, and the wire drawing air flow pressure is adjusted to 0.5 MPa, the feed rate is 150 g / min, and the outlet radius is adjusted to 2.5 cm. The dry powder will form a flocculent material after being fully drawn by the wire drawing machine.

[0057] Step 3: The flocculent material obtained in step 2 is pressed into film using a high-temperature roller with a pressing temperature of 120°C, a pressing speed of 18m / min, and a pressing thickness of 150±2μm to obtain an electrode film with good uniformity, which is Example 3.

[0058] Step 4: The electrode film prepared in step 3 is compounded with a metal current collector through a high-temperature rolling machine at a rolling temperature of 120°C and a rolling speed of 12m / min to produce a sandwich-structured battery electrode.

[0059] (2) Preparation of negative electrode: This embodiment relates to a method for preparing a dry negative electrode. Compared with the method for preparing a dry positive electrode in this embodiment, the ternary nickel-cobalt-manganese 523 material is replaced with graphite, and the rest is the same.

[0060] Example 4: Comparative Example This embodiment relates to a method for preparing a dry electrode, comprising the following steps: Step 1: Add the raw material graphite, conductive agent conductive carbon black, and binder polyvinylidene fluoride (PVDF) into the powder mixer in the ratio of 80:10:10. The mixing time is 2 hours. After the mixing is completed, take the mixed powder out of the powder mixer.

[0061] Step 2: Add the dry powder material in step 1 to the wire drawing machine. The inner wall of the wire drawing machine is not treated with a grinding bed. The wire drawing air flow pressure is adjusted to 1.0 MPa, the feed rate is 150 g / min, and the outlet radius is adjusted to 2.5 cm. The dry powder will form a flocculent material after being fully drawn by the wire drawing machine.

[0062] Step 3: The flocculent material obtained in step 2 is pressed into film using a high-temperature roller with a pressing temperature of 120°C, a pressing speed of 18m / min, and a pressing thickness of 150±2μm to obtain an electrode film with good uniformity, which is Example 4.

[0063] Step 4: The electrode film prepared in step 3 is compounded with a metal current collector through a high-temperature rolling machine at a rolling temperature of 120°C and a rolling speed of 12m / min to produce a sandwich-structured battery electrode.

[0064] Example 5: Comparative Example At the same time, wet-process lithium cobalt oxide and graphite positive and negative electrodes were prepared as the control group. The specific scheme is as follows: Step 1: Add lithium cobalt oxide or graphite negative electrode, conductive agent conductive carbon black, and binder PVDF 5130 into a homogenization tank in a ratio of 90:5:5, and then add NMP for wet homogenization at a stirring speed of 800 r / min for 3 hours; Step 2: Apply the slurry prepared in step 1 onto the current collector, using aluminum foil for the positive electrode and copper foil for the negative electrode, at a coating speed of 30 m / min; the oven temperature is 200°C to obtain wet-process positive and negative electrode sheets; Step 3: The wet-coated electrode obtained in step 2 is rolled by a rolling roller to increase the compaction density and bonding strength. The rolling speed is 10 m / min and the downward pressure is 20%, and wet-process positive and negative electrode sheets of the battery are obtained respectively.

[0065] Example 6: Assembling button batteries The button cells were assembled using the electrode sheets prepared in Examples 1 to 3 and Example 5 to obtain batteries 1-4 respectively. The assembly method was as follows: assemble in the order of positive electrode shell, battery positive electrode sheet, diaphragm, and battery negative electrode sheet, then use a pipette to draw 2 mL of lithium hexafluorophosphate battery electrolyte and inject it into the battery, then assemble into button cells in the order of gasket, spring pad, and negative electrode shell, and then use a sealing machine to seal. The assembly scheme is shown in Table 1: Table 1 Test example: (1) Electron microscopy: Depend on Figures 2 to 4 It can be seen that the method of the present invention can achieve complete fiberization of the binder and maintain the optimal state. After rolling into a film, the surface state is uniform and has good tensile strength and can be continuously batched into rolls.

[0066] (2) Tensile strength test: The test plan is as follows: first, cut the sample into samples with a width of 10mm and a length of 120mm, then connect the sample to a universal tensile testing machine, clamp 10mm at each end, the initial spacing is 100mm, set the tensile parameter and tensile speed to 5mm / min, and start the test.

[0067] in, Figure 1 This is a comparison chart of the tensile strength of the electrode membranes of Examples 1 to 4 of the present invention. It can be seen that the tensile strength of the positive electrode membrane of Example 4 is 0.0189 N / cm², and the tensile strength of the positive electrode membranes of Examples 2 and 3 is 0.042 N / cm²~0.046 N / cm². By comparison, it can be seen that the electrode membrane prepared by the present invention has good mechanical tensile properties compared with the traditional dry process.

[0068] (4) Battery cycle experiment: The test conditions are as follows: Step 1: Install and connect the battery to the test channel; Step 2: Let stand for 5 minutes; Step 3: 0.5C discharge to 2.5V, let stand for 30min; Step 4: Charge to 4.2V at 0.5C and let stand for 30 minutes; Step 5: Repeat steps 3 and 4.

[0069] Figure 5 The battery cycle results of each scheme are shown in Figure 2. It can be seen that the dry process can effectively improve the cycle life of the battery compared with the wet process. The wet electrode battery cycled for about 252 weeks, and the capacity had decayed to less than 80% of the initial capacity. The battery cycled for more than 300 cycles using the dry process had a capacity decay of less than 80%. Battery 2 cycled for nearly 400 cycles, and the use time increased by about 60%. It can be seen from the comparison that the dry process can effectively improve the battery life compared with the wet process, and the method of the present invention can further optimize the battery performance.

[0070] In summary, the degree of wire drawing of the adhesive of the present invention is high and controllable, which can effectively improve the quality of film formation, reduce the defects of the electrode film, and realize batch continuous production. Except for the wire drawing process, the rest of the processing of the present invention adopts mature processes and equipment in the current industry, without increasing other equipment investment, and can be produced without basically increasing costs, thereby enhancing the competitiveness of the product; and the electrode production process does not require any solvents, and zero pollution can be achieved. The process of the present invention is simple, fast, easy to operate, and has low requirements for equipment during the production process, which is convenient for actual production operations.

[0071] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a dry electrode, characterized in that: The method comprises the following steps: subjecting a mixed material to wire drawing under the conditions that the inner wall surface roughness of a wire drawing machine is Ra 6.3 μm to Ra 0.025 μm, the gas pressure during wire drawing is 0.3 MPa to 2.0 MPa, the feed rate is 30 g / min to 500 g / min, and the outlet radius is 2.0 cm to 4.0 cm, to obtain a flocculent material; the mixed material comprises an active material, a conductive agent and a binder; The flocculent material is subjected to a film pressing process to obtain an electrode film; and the electrode film is prepared into an electrode.

2. The method for preparing a dry electrode according to claim 1, characterized in that: Under the conditions that the inner wall surface roughness of the wire drawing machine is Ra 6.3μm~Ra 0.1μm, the gas pressure during wire drawing is 0.5 MPa~1.0 MPa, the feed rate is 100 g / min~300 g / min, and the outlet radius is 2.5 cm~3.0 cm, the mixed material is subjected to wire drawing to obtain a flocculent material.

3. The method for preparing a dry electrode according to claim 1, characterized in that: The binder includes at least one of polyvinylidene fluoride, polytetrafluoroethylene, polyacrylic acid, polyvinyl pyrrolidone, polyvinyl alcohol, and carboxymethyl cellulose.

4. The method for preparing a dry electrode according to claim 1, characterized in that: The active material includes any one of a positive electrode active material and a negative electrode active material; And / or, the conductive agent includes at least one of metal powder, acetylene black, Ketjen black, furnace black, conductive carbon black, conductive graphite, carbon nanotubes, carbon fiber, and graphene.

5. The method for preparing a dry electrode according to claim 4, characterized in that: The positive electrode active material includes at least one of lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, ternary nickel cobalt manganese lithium, nickel cobalt aluminum manganese lithium, sodium iron phosphate, sodium cobalt oxide, and sodium manganese oxide; And / or, the negative electrode active material includes at least one of hard carbon, soft carbon, artificial graphite, natural graphite, mesophase carbon microbeads, lithium titanate, and activated carbon.

6. The method for preparing a dry electrode according to any one of claims 1 to 5, characterized in that: The mass ratio of the active material, the conductive agent and the binder is 80:10:10-95:2.5:2.

5.

7. The method for preparing a dry electrode according to any one of claims 1 to 5, characterized in that: The mixed materials are mixed before the wire drawing process, and the mixing parameters are: a rotation speed of 100 r / min to 1500 r / min and a time of 0.5 h to 8 h.

8. The method for preparing a dry electrode according to any one of claims 1 to 5, characterized in that: The flocculent material is subjected to a film pressing process, comprising the following specific steps: the flocculent material is subjected to a film pressing process using a rolling roller, the rolling temperature is 80° C. to 250° C., and the rolling speed is ≤20 m / min; And / or, preparing the electrode film into an electrode comprises the following specific steps: compounding the electrode film and the metal current collector by a rolling roller, the compounding temperature is 80° C. to 250° C., and the compounding speed is ≤40 m / min, to obtain a battery electrode.

9. A dry electrode, characterized in that: The dry electrode is prepared by the preparation method according to any one of claims 1 to 8.

10. An application of a dry electrode, characterized in that: The dry electrode according to claim 9 is used in the preparation of lithium-ion batteries.

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