Dry-method pole piece with ultrathin current collector and secondary battery

Abstract

The invention relates to the technical field of battery pole piece design, and particularly discloses a dry-method pole piece with an ultrathin current collector and a secondary battery, the dry-method pole piece comprises a positive pole piece and a negative pole piece which are prepared by a dry method, and the positive pole piece comprises a positive pole supporting film and a positive current collector formed on the positive pole supporting film in a vacuum evaporation manner; the negative plate comprises a negative supporting film and a negative current collector which is formed on the negative supporting film in a magnetron sputtering and water electroplating manner in sequence; the positive electrode support film and the negative electrode support film are prepared by mixing main and auxiliary materials, fiberizing, granulating and rolling in sequence; the weight ratio of the positive active material to the conductive agent to the binder is (80-99): (0.5-15): (0.5-5), and the weight ratio of the negative active material to the conductive agent to the binder is (80-99.4): (0.1-15): (0.5-5). According to the invention, the dry-method self-supporting film is used as a substrate, and the pole piece is in contact with the current collector in a vacuum evaporation and magnetron sputtering manner, so that the thickness of the current collector can be accurately controlled and effectively reduced, and the energy density and capacity of the battery are improved.

Description

Technical Field

[0001] This invention relates to the field of battery electrode design technology, specifically to a dry electrode with an ultra-thin current collector and a secondary battery. Background Technology

[0002] Currently, in the fields of battery electrode preparation and current collector preparation, traditional processes have significant technical bottlenecks, making it difficult to meet market demands for high energy density, long cycle life, and low cost.

[0003] In battery electrode fabrication, the traditional wet electrode fabrication process involves dispersing active materials, conductive agents, and binders in an organic solvent (such as N-methylpyrrolidone, NMP) to form a slurry, which is then coated onto a current collector through processes such as coating and drying to form the electrode. However, this process has the following prominent problems: First, the use of organic solvents leads to high costs and complex recycling processes. The solvent recovery system not only accounts for 30%-40% of the production line equipment cost but also accounts for more than 50% of energy consumption, resulting in high production costs. Second, organic solvents are flammable, explosive, and volatile, generating organic waste gas, posing serious safety hazards and environmental pressures, requiring complex environmental treatment facilities. Third, during the drying process, the volatilization of organic solvents can easily cause the active materials to agglomerate, making it difficult to prepare thicker electrodes, limiting the improvement of battery energy density, and the interfacial bonding between the active material and the current collector is weak, affecting the cycle stability of the battery.

[0004] In terms of current collector fabrication, traditional rolling or electrolytic processes for preparing aluminum foil, copper foil, and other current collectors also have limitations. On the one hand, traditional processes are difficult to prepare ultra-thin current collectors with a thickness of <4μm, which cannot meet the requirements of lightweight and high energy density for new batteries such as solid-state batteries. On the other hand, ultra-thin current collectors (<4μm) prepared using traditional processes are prone to cracks and thickness fluctuations, resulting in surface resistivity fluctuations >15%, affecting the battery's conductivity and consistency. In addition, the interface stability between traditional current collectors and active materials is poor, and the interface impedance is prone to increase during charge and discharge, reducing the battery's cycle life and charge / discharge efficiency.

[0005] With the increasing demands on battery performance from new energy vehicles, energy storage, and other fields, there is an urgent need to develop new electrode fabrication processes and current collector fabrication technologies to overcome the shortcomings of traditional processes, improve the overall performance of batteries, and meet the market's pressing demand for high energy density, long cycle life, and low-cost batteries. Dry electrode fabrication processes and vacuum evaporation techniques for preparing ultrathin current collectors offer new technological pathways and development directions for solving these problems.

[0006] Patent application (CN114335409B) relates to a dry electrode and its preparation method, a dry cell, and a battery. The core preparation method involves stacking a separator, a dry electrode film, and a current collector, followed by hot rolling. The dry electrode film is located between the separator and the current collector, and the dry electrode film is integrated with the separator and current collector. When subjected to external impact or needle puncture, the electrode and separator are not easily misaligned. In the needle puncture test, the high-temperature shrinkage of the separator can be limited to avoid short circuits between the positive and negative electrodes. However, this patent uses foil and dry electrode sheets for solid-solid contact, resulting in poor interface contact, which is not conducive to improving the fast charging capability of the cell. In addition, this patent uses copper foil and aluminum foil with conventional processes, which is not conducive to improving the energy density of the cell.

[0007] Based on this technical background, this invention studies a dry electrode with an ultrathin current collector and a secondary battery. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a dry electrode sheet and a secondary battery with an ultra-thin current collector. The dry electrode sheet uses a dry self-supporting film as a substrate and is made into contact with the current collector through vacuum evaporation and magnetron sputtering. This allows for precise control and effective reduction of the current collector thickness, thereby increasing the weight ratio of the battery's active material, which in turn increases the battery's energy density and capacity. It also significantly improves the interface contact effect, reduces the cell's internal resistance, and enhances the cell's fast-charging performance.

[0009] To achieve the above objectives, the first aspect of the present invention provides a dry electrode sheet with an ultrathin current collector, comprising a dry-prepared positive electrode sheet and a dry-prepared negative electrode sheet.

[0010] The positive electrode sheet includes a positive electrode support film and a positive current collector formed thereon by vacuum evaporation;

[0011] The negative electrode sheet includes a negative electrode support film and a negative current collector formed thereon by magnetron sputtering and electroplating in sequence;

[0012] Both the positive electrode support membrane and the negative electrode support membrane are prepared sequentially through a process of mixing main and auxiliary materials, fiberization, granulation and rolling.

[0013] The main and auxiliary materials of the positive electrode support film include a positive electrode active material, a conductive agent and a binder, and the weight ratio of the positive electrode active material, the conductive agent and the binder is 80-99:0.5-15:0.5-5, preferably 90-98:0.5-5:1.5-5;

[0014] The main and auxiliary materials of the negative electrode support film include a negative electrode active material, a conductive agent and a binder, and the weight ratio of the negative electrode active material, the conductive agent and the binder is 80-99.4:0.1-15:0.5-5, preferably 90-98:0.5-5:1.5-5.

[0015] A second aspect of the present invention provides a secondary battery, which is obtained by cutting and stacking or winding the above-mentioned positive electrode sheet and negative electrode sheet.

[0016] The beneficial effects of this invention include:

[0017] (1) The dry electrode with ultra-thin current collector proposed in this invention uses a dry self-supporting film as the substrate. Through vacuum evaporation and magnetron sputtering, the electrode is made to contact the current collector. The thickness of the current collector can be precisely controlled and effectively reduced, thereby increasing the weight ratio of the active material in the battery, and thus increasing the energy density and capacity of the battery. At the same time, it greatly improves the interface contact effect, reduces the internal resistance of the cell, and improves the fast charging performance of the cell.

[0018] (2) The dry electrode with ultra-thin current collector proposed in this invention has a tight bond between the active material and the current collector, which helps to reduce the shedding of the active material during long-term use, effectively improving the reliability of the battery and extending the cycle life of the battery.

[0019] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0020] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings.

[0021] Figure 1 This is a top view schematic diagram of the positive electrode sheet in a specific embodiment of the dry electrode sheet with ultrathin current collector proposed in this invention.

[0022] Figure 2 This is a left-side view of the positive electrode in a specific embodiment of the dry electrode with ultrathin current collector proposed in this invention.

[0023] Figure 3 This is a top view schematic diagram of the negative electrode sheet in a specific embodiment of the dry electrode sheet with ultrathin current collector proposed in this invention.

[0024] Figure 4 This is a left-side view of the negative electrode sheet in a specific embodiment of the dry electrode sheet with ultra-thin current collector proposed in this invention.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1-Positive electrode, 2-Positive current collector, 3-Negative electrode, 4-Negative current collector, w1-Width of positive electrode, w2-Width of positive current collector, w3-Width of negative electrode, w4-Width of negative current collector. Detailed Implementation

[0027] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0028] This invention provides a dry-processed electrode with an ultrathin current collector, comprising a dry-processed positive electrode and a dry-processed negative electrode, the structural schematic diagrams of the two electrodes are shown below. Figure 1-4 As shown;

[0029] The positive electrode includes a positive electrode support film and a positive current collector formed thereon by vacuum evaporation;

[0030] The negative electrode sheet includes a negative electrode support film and a negative current collector formed thereon by magnetron sputtering and electroplating in sequence;

[0031] Both the positive electrode support membrane and the negative electrode support membrane are prepared sequentially through a process of mixing main and auxiliary materials, fiberization, granulation and rolling.

[0032] The main and auxiliary materials of the positive electrode support film include positive electrode active material, conductive agent and binder, and the weight ratio of positive electrode active material, conductive agent and binder is 80-99:0.5-15:0.5-5, preferably 90-98:0.5-5:1.5-5;

[0033] The main and auxiliary materials of the negative electrode support film include negative electrode active material, conductive agent and binder, and the weight ratio of negative electrode active material, conductive agent and binder is 80-99.4:0.1-15:0.5-5, preferably 90-98:0.5-5:1.5-5.

[0034] In this invention, a dry self-supporting film is used as the substrate. Vacuum evaporation and magnetron sputtering are used to make the electrode sheet contact the current collector. The thickness of the current collector can be precisely controlled and effectively reduced, thereby increasing the weight ratio of the active material in the battery, and thus increasing the energy density and capacity of the battery. At the same time, the interface contact effect is greatly improved, the internal resistance of the cell is reduced, and the fast charging performance of the cell is improved.

[0035] According to the present invention, the mixing temperature of the main and auxiliary materials is T1, wherein T1 < 19°C, preferably T1 < 15°C;

[0036] The temperature of fiberization, T2, is such that 19℃ < T2 < 150℃, and preferably 30℃ < T2 < 120℃.

[0037] The granulation process is at least one of mechanical pulverization, air jet milling, ultrasonic crushing, fluidized bed granulation, and spray drying.

[0038] The number of rolling cycles is N, where 1≤N≤6, preferably 1≤N≤4, and the temperature of each rolling cycle is T3, where 60℃≤T3≤200℃, preferably 75℃≤T3≤180℃.

[0039] According to the present invention, the thickness of the positive electrode support film is d1, wherein 30um≤d1≤300um, preferably 40um≤d1≤250um;

[0040] The thickness of the negative electrode support film is d2, wherein 30um≤d2≤300um, preferably 40um≤d2≤250um.

[0041] According to the present invention, the positive current collector is formed by vacuum evaporation of aluminum foil onto one side of the positive electrode support film;

[0042] The negative current collector is first formed by magnetron sputtering on one side of the negative electrode support film to form a nanoscale copper seed layer, and then the copper seed layer is thickened by electroplating to form an electroplated copper foil layer.

[0043] According to the present invention, the other side of the aluminum foil is laminated with the other side of another positive electrode support film;

[0044] The other side of the electroplated copper foil layer is composited with the other side of another negative electrode support film.

[0045] According to the present invention, the aluminum foil thickness is d3, wherein 100nm≤d3≤20um, preferably 1um≤d3≤8um;

[0046] The thickness of the copper seed layer is d4, wherein 10nm≤d4≤150nm, preferably 30nm≤d4≤100nm;

[0047] The thickness of the electroplated copper foil layer is d5, wherein 100nm≤d5≤8um, preferably 1mm≤d5≤4um.

[0048] According to the present invention, when the positive electrode support film initially contacts the positive current collector, and when the negative electrode support film initially contacts the negative current collector, both are solid-gas contacts.

[0049] According to the present invention, the width of the positive electrode support film is w1, wherein 150mm≤w1≤3000mm, preferably 200mm≤w1≤2000mm;

[0050] The width of the positive current collector is w2, wherein 150mm≤w2≤3000mm, preferably 200mm≤w2≤2000mm;

[0051] The width of the negative electrode support film is w3, wherein 150mm≤w3≤3000mm, preferably 200mm≤w3≤2000mm;

[0052] The width of the negative electrode current collector is w4, where 150mm≤w4≤3000mm, preferably 200mm≤w4≤2000mm.

[0053] The present invention also provides a secondary battery, which is obtained by cutting and stacking or winding the above-mentioned positive and negative electrode sheets.

[0054] According to the present invention, the secondary battery is any one of a pouch cell, a prismatic cell, or a cylindrical cell.

[0055] In this invention, the tight bonding between the active material and the current collector helps reduce the shedding of the active material during long-term use, effectively improving battery reliability and extending battery cycle life.

[0056] The present invention will be described in more detail below through embodiments.

[0057] Example 1

[0058] This embodiment provides a dry-processed electrode with an ultrathin current collector, including a dry-processed positive electrode and a dry-processed negative electrode. Schematic diagrams of the two electrodes are shown below. Figure 1-4 As shown;

[0059] The positive electrode includes a positive electrode support film and a positive current collector formed thereon by vacuum evaporation;

[0060] The negative electrode sheet includes a negative electrode support film and a negative current collector formed thereon by magnetron sputtering and electroplating in sequence;

[0061] Both the positive electrode support membrane and the negative electrode support membrane are prepared sequentially through a process of mixing main and auxiliary materials, fiberization, granulation and rolling.

[0062] The main and auxiliary materials of the positive electrode support film include the positive electrode active material, conductive agent and binder;

[0063] The main and auxiliary materials of the negative electrode support film include the negative electrode active material, conductive agent and binder.

[0064] In this embodiment, the fabrication processes of the positive electrode support film and the negative electrode support film, the positive electrode sheet and the negative electrode sheet, and the assembly process of the secondary battery are as follows.

[0065] 1) Preparation of positive and negative electrode active materials, conductive agents and binders: The positive electrode mixture and the negative electrode mixture are dispersed separately using a high-power mixer, and the temperature is controlled below 15℃ during the dispersion process;

[0066] 2) The above-mentioned uniformly mixed positive and negative electrode mixtures are subjected to fiberization in a twin-screw extruder at a temperature of 80°C and an extrusion speed of about 50 rpm, to obtain positive electrode fiberized mixtures and negative electrode fiberized mixtures respectively.

[0067] 3) The above-mentioned positive and negative electrode fiberized mixture is pulverized and granulated by an air mill to obtain positive and negative electrode mixture powder with fine particle size;

[0068] 4) The positive electrode mixture is processed into a film using a 5-roll mill, with the mill temperature controlled at approximately 80°C; after multiple stages of rolling, a self-supporting positive and negative electrode film is obtained.

[0069] 5) Place the positive electrode self-supporting film as the substrate on the sample stage of the vacuum evaporation equipment, close the equipment chamber door, and start the vacuum pump group to evacuate the chamber; put the high-purity aluminum ingot with a purity of 99.99% into the vacuum evaporation equipment to allow the aluminum to evaporate fully and form aluminum vapor in the chamber;

[0070] 6) Evaporation process: Control the temperature of the substrate between 100-150℃ to ensure the deposition effect of aluminum vapor on the substrate; when the thickness of the aluminum film is detected by the thickness monitor to reach about 6μm, stop the heating of the evaporation boat and turn off the relevant power supply; at the same time, attach the positive electrode dry self-supporting film to the other side of the aluminum foil to obtain the positive electrode sheet.

[0071] 7) Place the negative electrode self-supporting film as the substrate on the sample stage of the magnetron sputtering equipment and close the equipment chamber door; start the vacuum pump group to evacuate the chamber, and start magnetron sputtering after the target value is reached;

[0072] 8) Turn on the magnetron sputtering power supply to form a copper seed layer with a thickness of approximately 80 nm; after completion, turn off the power supply and gas valves;

[0073] 9) After preparing a copper foil of about 2 μm by electroplating, the two sides of the prepared copper foil are combined with a dry negative electrode to obtain a negative electrode sheet;

[0074] 10) Obtain the required battery through assembly and other processes.

[0075] Example 2

[0076] The difference between this embodiment and Embodiment 1 lies in the specific parameters of the preparation processes for the positive and negative electrode support films, as well as the positive and negative electrode sheets, as follows:

[0077] 1) Preparation of positive and negative electrode active materials, conductive agents and binders: The positive electrode mixture and the negative electrode mixture are dispersed separately using a high-power mixer, and the temperature is controlled below 18℃ during the dispersion process;

[0078] 2) The above-mentioned uniformly mixed positive and negative electrode mixtures are separately fiberized in a twin-screw extruder at a temperature of 120°C and an extrusion speed of about 50 rpm to obtain positive electrode fiberized mixtures and negative electrode fiberized mixtures.

[0079] 3) The above-mentioned positive and negative electrode fiberized mixture is pulverized and granulated by an air mill to obtain positive and negative electrode mixture powder with fine particle size;

[0080] 4) The positive electrode mixture is processed into a film using a 5-roll mill, with the mill temperature controlled at approximately 170°C; after multiple stages of rolling, a self-supporting positive and negative electrode film is obtained.

[0081] 5) Place the positive electrode self-supporting film as the substrate on the sample stage of the vacuum evaporation equipment, close the equipment chamber door, and start the vacuum pump group to evacuate the chamber; put the high-purity aluminum ingot with a purity of 99.99% into the vacuum evaporation equipment to allow the aluminum to evaporate fully and form aluminum vapor in the chamber;

[0082] 6) Evaporation process: Control the temperature of the substrate between 100-150℃ to ensure the deposition effect of aluminum vapor on the substrate; when the thickness of the aluminum film is detected by the thickness monitor to reach about 12μm, stop the heating of the evaporation boat and turn off the relevant power supply; at the same time, attach the positive electrode dry self-supporting film to the other side of the aluminum foil to obtain the positive electrode sheet.

[0083] 7) Place the negative electrode self-supporting film as the substrate on the sample stage of the magnetron sputtering equipment and close the equipment chamber door; start the vacuum pump group to evacuate the chamber, and start magnetron sputtering after the target value is reached;

[0084] 8) Turn on the magnetron sputtering power supply to form a copper seed layer with a thickness of approximately 80 nm; after completion, turn off the power supply and gas valves;

[0085] 9) After preparing a copper foil of about 4 μm by electroplating, the two sides of the prepared copper foil are combined with a dry negative electrode to obtain a negative electrode sheet;

[0086] 10) Obtain the required battery through assembly and other processes.

[0087] Example 3

[0088] The difference between this embodiment and Embodiment 1 lies in the specific parameters of the preparation processes for the positive and negative electrode support films, as well as the positive and negative electrode sheets, as follows:

[0089] 1) Preparation of positive and negative electrode active materials, conductive agents and binders: The positive electrode mixture and the negative electrode mixture are dispersed separately using a high-power mixer, and the temperature is controlled below 10℃ during the dispersion process;

[0090] 2) The above-mentioned uniformly mixed positive and negative electrode mixtures were subjected to fiberization in a twin-screw extruder at a temperature of 150°C and an extrusion speed of about 50 rpm, to obtain positive electrode fiberized mixtures and negative electrode fiberized mixtures respectively.

[0091] 3) The above-mentioned positive and negative electrode fiberized mixture is pulverized and granulated by an air mill to obtain positive and negative electrode mixture powder with fine particle size;

[0092] 4) The positive electrode mixture is processed into a film using a 4-roll mill, with the mill temperature controlled at approximately 180°C; after multiple stages of rolling, a self-supporting positive and negative electrode film is obtained.

[0093] 5) Place the positive electrode self-supporting film as the substrate on the sample stage of the vacuum evaporation equipment, close the equipment chamber door, and start the vacuum pump group to evacuate the chamber; put the high-purity aluminum ingot with a purity of 99.99% into the vacuum evaporation equipment to allow the aluminum to evaporate fully and form aluminum vapor in the chamber;

[0094] 6) Evaporation process: Control the temperature of the substrate between 100-150℃ to ensure the deposition effect of aluminum vapor on the substrate; when the thickness of the aluminum film is detected by the thickness monitor to reach about 10μm, stop the heating of the evaporation boat and turn off the relevant power supply; at the same time, attach the positive electrode dry self-supporting film to the other side of the aluminum foil to obtain the positive electrode sheet.

[0095] 7) Place the negative electrode self-supporting film as the substrate on the sample stage of the magnetron sputtering equipment and close the equipment chamber door; start the vacuum pump group to evacuate the chamber, and start magnetron sputtering after the target value is reached;

[0096] 8) Turn on the magnetron sputtering power supply to form a copper seed layer with a thickness of approximately 60 nm; after completion, turn off the power supply and gas valves;

[0097] 9) After preparing a copper foil of about 3 μm by electroplating, the two sides of the prepared copper foil are combined with a dry negative electrode to obtain a negative electrode sheet;

[0098] 10) Obtain the required battery through assembly and other processes.

[0099] Example 4

[0100] The difference between this embodiment and Embodiment 1 lies in the specific parameters of the preparation processes for the positive and negative electrode support films, as well as the positive and negative electrode sheets, as follows:

[0101] 1) Preparation of positive and negative electrode active materials, conductive agents and binders: The positive electrode mixture and the negative electrode mixture are dispersed separately using a high-power mixer, and the temperature is controlled below 12℃ during the dispersion process;

[0102] 2) The above-mentioned uniformly mixed positive and negative electrode mixtures are separately fiberized in a twin-screw extruder at a temperature of 180℃ and an extrusion speed of about 50 rpm to obtain positive electrode fiberized mixtures and negative electrode fiberized mixtures.

[0103] 3) The above-mentioned positive and negative electrode fiberized mixture is pulverized and granulated by an air mill to obtain positive and negative electrode mixture powder with fine particle size;

[0104] 4) The positive electrode mixture is processed into a film using a 4-roll mill, with the mill temperature controlled at approximately 60°C; after multiple stages of rolling, a self-supporting positive and negative electrode film is obtained.

[0105] 5) Place the positive electrode self-supporting film as the substrate on the sample stage of the vacuum evaporation equipment, close the equipment chamber door, and start the vacuum pump group to evacuate the chamber; put the high-purity aluminum ingot with a purity of 99.99% into the vacuum evaporation equipment to allow the aluminum to evaporate fully and form aluminum vapor in the chamber;

[0106] 6) Evaporation process: Control the temperature of the substrate between 100-150℃ to ensure the deposition effect of aluminum vapor on the substrate; when the thickness of the aluminum film is detected by the thickness monitor to reach about 13μm, stop the heating of the evaporation boat and turn off the relevant power supply; at the same time, attach the positive electrode dry self-supporting film to the other side of the aluminum foil to obtain the positive electrode sheet.

[0107] 7) Place the negative electrode self-supporting film as the substrate on the sample stage of the magnetron sputtering equipment and close the equipment chamber door; start the vacuum pump group to evacuate the chamber, and start magnetron sputtering after the target value is reached;

[0108] 8) Turn on the magnetron sputtering power supply to form a copper seed layer with a thickness of approximately 12 nm; after completion, turn off the power supply and gas valves;

[0109] 9) After preparing a copper foil of about 6 μm by electroplating, the two sides of the prepared copper foil are combined with a dry negative electrode to obtain a negative electrode sheet;

[0110] 10) Obtain the required battery through assembly and other processes.

[0111] Comparative Example 1

[0112] 1) The same formulation as in Example 1 was used to prepare the electrode sheets by a wet process, wherein the positive electrode aluminum foil was 13 μm and the negative electrode copper foil was 6 μm.

[0113] 2) Solid-state batteries are obtained through assembly and other processes.

[0114] Table 1 Comparison results of various embodiments and comparative examples.

[0115]

[0116] As shown in Table 1, based on the comparison results of Examples 1-4 and Comparative Example 1, it can be seen that the present invention uses a dry self-supporting film as a substrate, and through vacuum evaporation and magnetron sputtering, the electrode sheet and the current collector are brought into contact. The thickness of the current collector can be precisely controlled and effectively reduced, thereby increasing the weight ratio of the active material in the battery, and thus increasing the energy density and capacity of the battery. At the same time, it also greatly improves the interface contact effect, reduces the internal resistance of the cell, and improves the fast charging performance, first-time efficiency and cycle capacity retention of the cell.

[0117] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A dry electrode having an ultra-thin current collector, characterized in that, The positive electrode sheet and the negative electrode sheet are prepared by dry method; The positive electrode sheet comprises a positive electrode support film and a positive current collector formed on the positive electrode support film by vacuum evaporation method; The negative electrode sheet comprises a negative electrode support film and a negative current collector formed on the negative electrode support film by magnetron sputtering and electroless plating in sequence; The positive electrode support film and the negative electrode support film are prepared by mixing main and auxiliary materials, fiberization, granulation and rolling in sequence; The main and auxiliary materials of the positive electrode support film comprise positive electrode active material, conductive agent and binder, and the weight ratio of the positive electrode active material, the conductive agent and the binder is 80-99:0.5-15:0.5-5, preferably 90-98:0.5-5:1.5-5; The main and auxiliary materials of the negative electrode support film comprise negative electrode active material, conductive agent and binder, and the weight ratio of the negative electrode active material, the conductive agent and the binder is 80-99.4:0.1-15:0.5-5, preferably 90-98:0.5-5:1.5-5.

2. The dry electrode plate of claim 1, wherein The temperature of the main and auxiliary material mixing is T1, wherein T1<19℃, preferably T1<15℃; The temperature of the fiberization is T2, wherein 19℃<T2<150℃, preferably 30℃<T2<120℃; The granulation process is at least one of mechanical crushing method, airflow crushing method, ultrasonic crushing, fluidized bed granulation and spray drying process; The number of rolling is N, wherein 1≤N≤6, preferably 1≤N≤4, and the temperature of each rolling is T3, wherein 60℃≤T3≤200℃, preferably 75℃≤T3≤180℃.

3. The dry electrode plate of claim 1, wherein The thickness of the positive electrode support film is d1, wherein 30um≤d1≤300um, preferably 40um≤d1≤250um; The thickness of the negative electrode support film is d2, wherein 30um≤d2≤300um, preferably 40um≤d2≤250um.

4. The dry pole of claim 1, wherein The positive current collector is formed by vacuum evaporation of aluminum foil on one side of the positive electrode support film; The negative current collector is formed by magnetron sputtering to form a nano copper seed layer on one side of the negative electrode support film, and then electroless plating to thicken the copper seed layer to form a water electroless plated copper foil layer.

5. The dry electrode plate of claim 4, wherein, The other side of the aluminum foil is combined with the other side of another positive electrode support film; The other side of the water electroless plated copper foil layer is combined with the other side of another negative electrode support film.

6. The dry electrode plate of claim 4, wherein The thickness of the aluminum foil is d3, wherein 100nm≤d3≤20um, preferably 1um≤d3≤8um; The thickness of the copper seed layer is d4, wherein 10nm≤d4≤150nm, preferably 30nm≤d4≤100nm; The thickness of the water electroless plated copper foil layer is d5, wherein 100nm≤d5≤8um, preferably 1mm≤d5≤4um.

7. The dry pole of claim 1, wherein The initial contact between the positive electrode support film and the positive current collector, and the initial contact between the negative electrode support film and the negative current collector are solid-gas contact.

8. The dry pole of claim 1, wherein The width of the positive electrode support film is w1, wherein 150mm≤w1≤3000mm, preferably 200mm≤w1≤2000mm; The positive electrode current collector has a width w2, wherein 150mm≤w2≤3000mm, preferably 200mm≤w2≤2000mm; The negative electrode support film has a width w3, wherein 150mm≤w3≤3000mm, preferably 200mm≤w3≤2000mm; The negative electrode current collector has a width w4, wherein 150mm≤w4≤3000mm, preferably 200mm≤w4≤2000mm.

9. A secondary battery characterized by comprising: The secondary battery is obtained by stacking or winding the positive electrode sheet and the negative electrode sheet according to any one of claims 1-8 after cutting.

10. The secondary battery according to claim 9, characterized by The secondary battery is any one of soft package, square shell or cylindrical secondary battery.

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