Dry manufacturing method of solid-state electrode plate

Abstract

The invention is suitable for the technical field of battery manufacturing, and provides a dry manufacturing method of a solid-state electrode plate. The dry manufacturing method of the solid-state electrode plate comprises the following steps: uniformly mixing electrode material powder, conductive material powder and binder powder according to a preset proportion to obtain mixed material powder; fibrillating the mixed material powder under a first preset condition to soften and extend the binder powder into filaments, and uniformly coating the filaments on the surface of the electrode material to obtain fibrillated powder; carrying out fiber network strengthening treatment on the fibrillated powder, and screening the fibrillated powder into uniform powder particles; and adding the screened powder particles into a multi-roller rolling device, carrying out double-sided film formation on the screened powder particles through the multi-roller rolling device, and rolling and compounding the powder particles onto a current collector to obtain the double-sided composite solid-state electrode plate. According to the dry manufacturing method of the solid-state electrode plate, the problems of powder falling, wrinkling and breakage of the electrode can be effectively avoided, the production process is simplified, and the mechanical property and the electrochemical property of the electrode are improved.

Description

Technical Field

[0001] This application belongs to the field of all-solid-state battery manufacturing technology, and particularly relates to a dry manufacturing method for solid-state electrode sheets. Background Technology

[0002] Traditional lithium-ion battery manufacturing primarily employs a wet process, which involves dispersing electrode materials, conductive agents, and binders in a solvent to form a slurry, coating it onto a current collector, and then subjecting it to drying and rolling processes. The wet process suffers from high costs, significant environmental pollution, and complex operations, and it struggles to meet the demands for high energy density, rapid charge / discharge, and long lifespan. Furthermore, the wet process exhibits poor compatibility with solid-state electrolyte systems, limiting the development of all-solid-state lithium-ion batteries.

[0003] Dry manufacturing technology for solid-state electrode sheets is an alternative solution. Since its manufacturing process does not require the use of solvents, but directly rolls dry powder materials into shape by mechanical means, it has advantages such as low cost, high energy density, and good safety, and is especially suitable for the production of all-solid-state lithium-ion batteries.

[0004] However, existing dry manufacturing processes for solid-state electrodes still suffer from problems such as insufficient electrode powder adhesion, uneven film formation, easy powder and slag shedding, wrinkles and breakage during film-current collector bonding, and poor process continuity. These problems hinder the industrial-scale production of solid-state electrodes, thus limiting the industrialization of solid-state lithium-ion batteries. Therefore, a dry electrode manufacturing process that can solve these manufacturing problems is urgently needed. Summary of the Invention

[0005] This application provides a dry manufacturing method for solid electrode sheets, which can realize the dry manufacturing process of solid electrode sheets using multi-roller pressing equipment. It can simplify the dry manufacturing process of solid electrode sheets and efficiently and stably prepare solid electrode sheets that meet performance requirements.

[0006] In a first aspect, embodiments of this application provide a dry manufacturing method for solid electrode sheets, comprising: mixing electrode material powder, conductive material powder, and binder powder uniformly in a preset ratio to obtain a mixed material powder; subjecting the mixed material powder to fibrillation treatment under a first preset condition, so that the binder powder softens and extends into fine filaments, and uniformly coats the surface of the electrode material to obtain fibrillated powder; subjecting the fibrillated powder to fiber network reinforcement treatment and sieving it into uniform powder particles; and adding the sieved powder particles into the feeding trough of a multi-roller pressing device. The multi-roller pressing equipment further includes a current collector unwinding device and a current collector rewinding device. The current collector unwinding device is equipped with a current collector and a current collector preheating component. One end of the current collector is connected to the unwinding device, and the other end is connected to the rewinding device. After the current collector is heated to a preset temperature by the current collector preheating component, it passes through the multi-roller pressing equipment under the traction of the unwinding device and the rewinding device. The multi-roller pressing equipment is configured with target parameters to roll the sieved powder particles onto the current collector to obtain the solid electrode sheet.

[0007] In this embodiment, the uniformity of the material system composition is ensured by uniformly mixing electrode material powder, conductive material powder, and binder powder in a preset ratio. Under a first preset condition, fibrillation treatment softens the binder powder and extends it into fine filaments, uniformly coating the electrode material surface, enhancing the adhesion between powder particles and the interfacial bonding strength. The fibrillated powder is then subjected to fiber network reinforcement treatment and sieved into uniform powder particles, improving the powder's flowability and particle size uniformity. By adding the sieved powder particles to a multi-roller pressing device configured with target parameters, and with the synergistic action of the current collector unwinding and rewinding devices, continuous and uniform rolling of the powder particles onto the current collector is achieved. This produces a dense, firmly bonded, solvent-free solid electrode sheet, effectively avoiding problems such as electrode powder shedding, wrinkling, and breakage, simplifying the production process, and improving the electrode's mechanical and electrochemical properties.

[0008] In some embodiments, the multi-roller pressing equipment includes at least six rollers arranged side by side, the rollers having a diameter of 200mm-350mm and a roller surface width of 200mm-400mm, and the rollers being arranged side by side.

[0009] In some embodiments, the target parameters include: the temperature range of the roller surface is 80-150°C; the gap width between adjacent rollers is 60μm-300μm; and the roller pressure range is 2T-6T.

[0010] In some embodiments, the six rollers arranged side by side are, from left to right, a first roller, a second roller, a third roller, a fourth roller, a fifth roller, and a sixth roller. The target parameters further include: the first roller and the sixth roller have the same rotational speed but opposite directions; the second roller and the fifth roller have the same rotational speed but opposite directions; and the third roller and the fourth roller have the same rotational speed but opposite directions.

[0011] In some embodiments, the multi-roller pressing device includes a first feeding trough and a second feeding trough. The first feeding trough is disposed between the first roller and the second roller, and the second feeding trough is disposed between the fifth roller and the sixth roller. The step of pressing the sieved powder particles onto the current collector using the multi-roller pressing device includes: pressing the powder particles in the first feeding trough using the first roller and the second roller to obtain a first electrode film initially formed, wherein the temperature difference between the roller surfaces of the first roller and the second roller is in the range of 0-10℃, and the gap distance between the rollers is in the range of 100-300μm; pressing the powder particles in the second feeding trough using the fifth roller and the sixth roller to obtain a second electrode film initially formed, wherein the temperature difference between the roller surfaces of the fifth roller and the sixth roller is in the range of 0-10℃, and the gap distance between the rollers is in the range of 100-300μm; and pressing the powder particles in the second feeding trough using the second roller and the third roller to obtain a second electrode film initially formed, wherein the temperature difference between the roller surfaces of the fifth roller and the sixth roller is in the range of 0-10℃, and the gap distance between the rollers is in the range of 100-300μm; and pressing the first electrode film using the second roller and the third roller to obtain a second electrode film initially formed. The first electrode film is thinned to obtain a thinned first electrode film. The temperature difference between the roller surfaces of the second and third rollers ranges from 0-20°C, and the gap between the rollers of the second and third rollers ranges from 50-150 μm. The second electrode film, initially formed, is then thinned using the fourth and fifth rollers to obtain a thinned second electrode film. The temperature difference between the roller surfaces of the fourth and fifth rollers also ranges from 0-20°C. The roll gap distance ranges from 50 to 150 μm; the current collector passes through the roll gap between the third and fourth rollers, and the third and fourth rollers are used to roll the thinned first electrode film onto one side of the current collector, and roll the thinned second electrode film onto the other side of the current collector. The roller surface temperatures between the third and fourth rollers are the same or similar, and the roll gap distance between the third and fourth rollers is determined based on the roll gap distance between the second and third rollers.

[0012] In some embodiments, the method further includes: the roll gap distance between the third roller and the fourth roller is: the roll gap distance between the second roller and the third roller multiplied by 2, minus 50 μm.

[0013] In some embodiments, the current collector preheating assembly includes two heating modules arranged opposite to each other, the heating modules being laser heating modules or infrared heating modules; when the current collector is pulled through the current collector preheating assembly by the unwinding device, the current collector is preheated to the preset temperature by the two heating modules, the preset temperature being 50-100℃.

[0014] In some embodiments, the binder powder is polytetrafluoroethylene (PTFE) with a particle size range of 50-200 μm.

[0015] In some embodiments, the first preset conditions include: the stirring linear speed of the fibrillation treatment is in the range of 30 to 50 meters per minute; the stirring temperature of the fibrillation treatment is in the range of 70°C to 100°C; and the stirring time of the fibrillation treatment is in the range of 3 to 5 minutes.

[0016] In some embodiments, the fiber network strengthening treatment includes: extruding and shearing the fibrillated powder using a twin-screw extruder; the sieving to obtain uniform powder particles includes: sieving the powder that has undergone the fiber network strengthening treatment through a sieve with a pore size of 0.5 mm-1 mm to obtain powder particles with a particle size of 0.1 mm-1 mm. In some embodiments, the step of uniformly mixing the electrode material powder, conductive material powder, and binder powder in a preset ratio to obtain a mixed material powder includes: stirring and mixing the electrode material powder and the conductive material powder at a temperature range of room temperature to 40°C for 10-20 minutes; adding the binder powder at a temperature range of 10°C-20°C and stirring and mixing for 5-10 minutes.

[0017] In some embodiments, the preset proportions include: the mass proportion of the electrode material is 94% to 96%, the mass proportion of the conductive material is 2% to 3%, and the mass proportion of the binder powder is 2% to 3%. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A flowchart illustrating a dry manufacturing method for a solid electrode sheet provided in an embodiment of this application;

[0020] Figure 2 Scanning electron microscope image of powder particles after fiber network reinforcement treatment provided in an embodiment of this application;

[0021] Figure 3 This is a schematic diagram of the structure of a multi-roller pressing device provided in an embodiment of this application;

[0022] Figure 4 This is a scanning electron microscope image of a solid electrode sheet provided in an embodiment of this application;

[0023] Figure 5 A scanning electron microscope image of a solid electrode sheet obtained using the parameters in Example 1, provided as an embodiment of this application;

[0024] Figure 6 A scanning electron microscope image of a solid electrode sheet obtained using the parameters in Example 2, provided as an embodiment of this application;

[0025] Figure 7 A physical image of a solid electrode sheet obtained using the parameters in Comparative Example 1, provided as an embodiment of this application. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the accompanying drawings in the present invention are for illustrative and descriptive purposes only and are not intended to limit the scope of protection of the present invention. Furthermore, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this invention illustrate operations implemented according to some embodiments of the present invention. It should be understood that the operations in the flowcharts may not be implemented in sequence, and steps without logical contextual relationships may be reversed or implemented simultaneously. In addition, those skilled in the art, guided by the content of this invention, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts.

[0027] Furthermore, the embodiments described herein are merely some, not all, of the embodiments of the invention. The components of the embodiments of the invention described and illustrated herein can typically be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0028] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0029] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0030] Furthermore, terms such as "horizontal" and "vertical" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0031] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] Figure 1 A flowchart illustrating a dry manufacturing method for a solid electrode sheet provided in an embodiment of this application.

[0033] Reference Figure 1 A dry manufacturing method for solid-state electrode sheets includes:

[0034] S110: Mix electrode material powder, conductive material powder and binder powder evenly according to a preset ratio to obtain mixed material powder.

[0035] In some embodiments, the binder powder is polytetrafluoroethylene (PTFE) with a particle size range of 50-200 μm. Using PTFE with a particle size range of 50-200 μm results in higher fiber strength during subsequent fibrillation and fiber network reinforcement treatments, which can effectively improve the film strength of the electrode.

[0036] In some embodiments, the electrode material powder may include: positive electrode materials such as high-nickel ternary, lithium-rich manganese-based, and high-voltage lithium nickelate; or negative electrode materials such as graphite, graphite and silicon-carbon mixtures, and silicon-carbon. In some embodiments, the conductive material powder may be: carbon black, carbon fiber (VGCF), or carbon nanotubes.

[0037] In some embodiments, electrode material powder, conductive material powder, and binder powder are mixed uniformly in a preset ratio to obtain a mixed material powder. This may include: stirring and mixing the electrode material powder and conductive material powder at a temperature range of room temperature to 40°C for 10-20 minutes; and adding binder powder at a temperature range of 10°C to 20°C and stirring and mixing for 5-10 minutes. By using segmented temperature-controlled mixing, the three materials can be mixed at appropriate temperatures, resulting in a more uniform mixture and a mixed material powder with better performance.

[0038] In some embodiments, the preset proportions include: the mass proportion of the electrode material is 94% to 96%, the mass proportion of the conductive material is 2% to 3%, and the mass proportion of the binder powder is 2% to 3%.

[0039] As an example, in one possible preset ratio, the electrode material accounts for 95% of the mass, the conductive material accounts for 2% of the mass, and the binder powder accounts for 3% of the mass. Alternatively, in another possible preset ratio, the electrode material accounts for 94% of the mass, the conductive material accounts for 3% of the mass, and the binder powder accounts for 3% of the mass. Or, in yet another possible preset ratio, the electrode material accounts for 96% of the mass, the conductive material accounts for 2% of the mass, and the binder powder accounts for 2% of the mass.

[0040] S120: The mixed material powder is subjected to fibrillation treatment under a first preset condition so that the binder powder is softened and extended into filaments, and uniformly coated on the surface of the electrode material to obtain fibrillated powder.

[0041] In some embodiments, the first preset conditions include: the stirring linear speed of the fibrillation treatment is in the range of 30 to 50 meters per minute; the stirring temperature of the fibrillation treatment is in the range of 70°C to 100°C; and the stirring time of the fibrillation treatment is in the range of 3 to 5 minutes.

[0042] When the stirring speed of the original fiberization treatment is in the range of 30 to 50 meters per minute, the binder powder can be fully fiberized and fully coated on the surface of the electrode material, with a high degree of fiberization and no over-fiberization.

[0043] Setting the stirring temperature range for fibrillation treatment to 70℃-100℃ can prevent insufficient fibrillation due to insufficient temperature, which would lead to poor fiber strength. Furthermore, it can prevent over-fibrillation caused by excessively high temperatures, which would make the already fibrillated fibers prone to breakage, resulting in discontinuous film formation and reduced strength.

[0044] Meanwhile, when the temperature is strictly controlled within the above range, the fibrillation time should not be too long. Excessive time can easily lead to the breakage of the already fibrillated fibers, resulting in insufficient and uneven coating of the fiber filaments on the electrode powder surface, making film formation difficult.

[0045] S130: The fibrillated powder is subjected to fiber network reinforcement treatment and sieved into uniform powder particles.

[0046] In some embodiments, the fiber network strengthening process includes: extruding and shearing the fibrillated powder using a twin-screw extruder. Sieving into uniform powder particles includes: sieving the fiber network strengthened powder through a sieve with an aperture of 0.5 mm-1 mm to obtain powder particles with a particle size of 0.1 mm-1 mm.

[0047] Within the above parameter range, fiber network reinforcement treatment and sieving yield uniform powder particles. When such powder particles are fed into a multi-roller pressing device, there will be no issues such as material jamming or uneven feeding, making it easier to prepare electrode films with uniform areal density.

[0048] Figure 2 This is a scanning electron microscope image of powder particles after fiber network reinforcement, provided in an embodiment of this application.

[0049] like Figure 2 As shown, the powder particles obtained by fibrillation, fiber network strengthening treatment and sieving using the above parameters have uniform particle size and sufficient fiber coating, resulting in better film-forming performance.

[0050] S140: The sieved powder particles are added to the feeding trough of the multi-roller pressing equipment. The multi-roller pressing equipment also includes a collector unwinding device and a collector winding device. The collector unwinding device is equipped with a collector and a collector preheating component. One end of the collector is connected to the unwinding device and the other end is connected to the winding device. After the collector is heated to a preset temperature by the collector preheating component, it passes through the multi-roller pressing equipment under the traction of the unwinding device and the winding device.

[0051] S150: The multi-roller pressing equipment is configured with target parameters to press the sieved powder particles onto the current collector to obtain solid electrode sheets.

[0052] In some embodiments, the multi-roller pressing equipment includes at least six rollers arranged side by side, with a diameter of 200mm-350mm and a roller surface width of 200mm-400mm.

[0053] In some implementations, the target parameters include: a roller surface temperature range of 80°C to 150°C; a roller gap width range of 60μm to 300μm between adjacent rollers; and a roller pressure range of 2T to 6T.

[0054] Figure 3 This is a schematic diagram of the structure of a multi-roller pressing device provided in an embodiment of this application.

[0055] In some implementations, reference Figure 3 The multi-roller pressing equipment includes six rollers arranged side-by-side, from left to right: roller 201, roller 202, roller 203, roller 204, roller 205, and roller 206. Target parameters also include: rollers 201 and 206 rotate at the same speed but in opposite directions; rollers 202 and 205 rotate at the same speed but in opposite directions; and rollers 203 and 206 rotate at the same speed but in opposite directions. Specifically, the rotational speed, temperature, and pressure of rollers 203 and 204 must be kept consistent.

[0056] As an example, in the target parameters, the rotation speed of the first roller 201 can be set to 1 mm / min, with the roller rotating forward; the rotation speed of the second roller 202 can be set to 1.05-1.6 mm / min, with the roller rotating in reverse; the rotation speed of the third roller 203 can be set to 1.3-5 mm / min, with the roller rotating forward; the rotation speed of the fourth roller 204 can be set to 1.3-5 mm / min, with the roller rotating in reverse; the rotation speed of the fifth roller 205 can be set to 1.05-1.6 mm / min, with the roller rotating forward; and the rotation speed of the sixth roller 206 can be set to 1 mm / min, with the roller rotating in reverse.

[0057] In some implementations, the multi-roller pressing equipment may have more rollers. When there are more rollers, the arrangement can be referenced in the above example, and will not be repeated here.

[0058] In some embodiments, the multi-roller pressing equipment includes a first feeding trough 207 and a second feeding trough 208. The first feeding trough 207 is disposed between the first roller 201 and the second roller 202, and the second feeding trough 208 is disposed between the fifth roller 205 and the sixth roller 206.

[0059] The sieved powder particles are rolled onto the current collector 211 using a multi-roller pressing device, including: using a first roller 201 and a second roller 202 to roll the powder particles in the first feeding trough 207 to obtain a first electrode film 214 for initial film formation, wherein the temperature difference between the roller surfaces of the first roller 201 and the second roller 202 is in the range of 0-10℃, and the roller gap distance between the first roller 201 and the second roller 202 is in the range of 100-300μm.

[0060] The powder particles in the second feeding trough 208 are rolled using the fifth roller 205 and the sixth roller 206 to obtain the first electrode film 216. The temperature difference between the roller surfaces of the fifth roller 205 and the sixth roller 206 is in the range of 0-10℃, and the roller gap distance between the fifth roller 205 and the sixth roller 206 is in the range of 100-300μm.

[0061] The first electrode film 214, which is initially formed, is thinned using the second roller 202 and the third roller 203 to obtain the thinned first electrode film 215. The temperature difference between the roller surfaces of the second roller 202 and the third roller 203 is in the range of 0-20℃, and the roller gap distance between the second roller 202 and the third roller 203 is in the range of 50-150μm.

[0062] The second electrode film 216, which was initially formed, is thinned using the fourth roller 204 and the fifth roller 205 to obtain the thinned second electrode film 217. The temperature difference between the roller surfaces of the fourth roller 204 and the fifth roller 205 is in the range of 0-20℃, and the gap between the rollers of the fourth roller 204 and the fifth roller 205 is in the range of 50-150μm.

[0063] The current collector 211 passes through the roll gap between the third roller 203 and the fourth roller 204. The third roller 203 and the fourth roller 204 roll the thinned first electrode film 215 onto one side of the current collector 211 and roll the thinned second electrode film 217 onto the other side of the current collector 211. The roller surface temperatures between the third roller 203 and the fourth roller 204 are the same or similar. The roll gap distance between the third roller 203 and the fourth roller 204 is determined based on the roll gap distance between the second roller 202 and the third roller 203.

[0064] In some embodiments, the roll gap distance between the third and fourth rollers is calculated as: the roll gap distance between the second and third rollers multiplied by 2, minus 50 μm. That is, the roll gap width D between the fourth roller 204 and the third roller 203 can be determined by the following formula:

[0065]

[0066] in, The gap width between the second roller 202 and the third roller 203.

[0067] In some embodiments, the current collector unwinding device 209 is positioned above the third roller 203 and the fourth roller 204. The current collector roll is mounted on the unwinding device 209, and the width of the roll is the same as or similar to the film width. The unwinding device 209 also has web correction and tension control functions, with web correction accuracy in the range of ±0.1mm and tension control in the range of 1-100N.

[0068] The correction component 212 of the winding device 210 and the correction component (not shown) of the unwinding device 209 need to be fixed at the same horizontal position to improve the neatness during winding.

[0069] In some embodiments, the first hydraulic station 213 and the second hydraulic station 214 are pressurized by a double-sided pressurization method, with a pressure of 1-15T, and the pressure fluctuation can be controlled within the range of 0-0.4T during the rolling process.

[0070] In some embodiments, the current collector preheating assembly includes two heating modules arranged opposite each other, which are laser heating modules or infrared heating modules. When the current collector is drawn through the current collector preheating assembly by the unwinding device, the two heating modules preheat the current collector to a preset temperature, which is 50-100°C. By preheating the current collector, the pre-coated carbon layer on both sides of the current collector can be softened, increasing the adhesion of the current collector to the mixed material powder.

[0071] In this application, the compositional consistency of the material system is ensured by uniformly mixing electrode material powder, conductive material powder, and binder powder in a preset ratio. Under a first preset condition, fibrillation treatment softens the binder powder and extends it into fine filaments, uniformly coating the electrode material surface, thus enhancing the adhesion between powder particles and the interfacial bonding strength. The fibrillated powder is then subjected to fiber network reinforcement treatment and sieved into uniform powder particles, improving the powder's flowability and particle size uniformity. By adding the sieved powder particles to a multi-roller pressing device configured with target parameters, and with the synergistic action of the current collector unwinding and rewinding devices, continuous and uniform rolling of the powder particles onto the current collector is achieved. This produces a dense, firmly bonded, solvent-free solid dry electrode, effectively avoiding problems such as electrode powder shedding, wrinkling, and breakage, simplifying the production process, and improving the mechanical and electrochemical properties of the electrode, demonstrating significant practical value.

[0072] Figure 4 This is a scanning electron microscope image of a solid electrode sheet provided in an embodiment of this application.

[0073] from Figure 4As can be seen from the above, the solid electrode sheet prepared by the dry manufacturing method of solid electrode sheet provided in this application has a dense structure, a strong bond, and a stable physical structure, thus exhibiting good electrical performance.

[0074] The following provides two embodiments and one comparative example, based on the above configuration, to further illustrate the dry manufacturing method of solid electrode sheets.

[0075] Example 1:

[0076] In Example 1, the electrode material is graphite, the conductive material is carbon black, and the binder is PTFE.

[0077] First, graphite, carbon black, and PTFE are mixed in a mass ratio of 95:3:2. During mixing, the graphite and carbon black are first stirred at 10 m / min for 10 minutes at room temperature. Then, the temperature is lowered to 15°C, and the PTFE material is added, and the mixture is stirred at 15 m / min for 10 minutes until homogeneous.

[0078] Then, the mixed material was stirred at high speed at 45 m / min and at 80°C for 4 min to fibrillate it, resulting in fibrillated powder.

[0079] Next, the fibrillated powder is subjected to fiber network reinforcement treatment. Fiber network reinforcement treatment can be achieved by stirring in a twin-screw extruder with a speed ratio of 1:1.4 for 60 minutes. Then, the fiber network reinforced powder is sieved through a 1 mm sieve to obtain powder particles with a particle size of 1 mm.

[0080] Finally, the powder particles are evenly added to the two feed ports of the six-roll press, and the six-roll press is configured according to the following target parameters: the surface temperatures of the first to sixth rolls are set to 100℃, 100℃, 80℃, 80℃, 100℃, and 100℃ respectively; the speed ratio is adjusted to 1:1.3:1.5:1.5:1.3:1; the roll gaps are adjusted to 300μm, 150μm, 250μm, 150μm, and 300μm respectively; the bilateral pressure is 10T; and the current collector winding speed is 2m / min.

[0081] After the setup is complete, start the current collector unwinding device and the six-roller pressing equipment to manufacture the electrode sheet. After winding, the prepared solid electrode sheet can be obtained.

[0082] Example 2:

[0083] In Example 2, the electrode material is graphite, the conductive material is carbon black, and the binder is PTFE.

[0084] First, ternary lithium, carbon black, and PTFE were mixed in a mass ratio of 95:2:3. During mixing, the ternary lithium and carbon black were first stirred at 8 m / min for 20 min at room temperature. Then, the temperature was lowered to 15°C, and the PTFE material was added, and the mixture was stirred at 10 m / min for 10 min until homogeneous.

[0085] Then, the mixed material was stirred at high speed at 35 m / min and at 60°C for 3 min to fibrillate it, resulting in fibrillated powder.

[0086] Next, the fibrillated powder is subjected to fiber network reinforcement treatment, which can be achieved by stirring with a twin-screw extruder at a speed ratio of 1:1.4 for 10 minutes. Then, the fiber network-reinforced powder is sieved through a 1mm sieve to obtain powder particles with a particle size of 1mm.

[0087] Finally, the powder particles are evenly added to the two feeding ports of the six-roll press, and the six-roll press is configured according to the following target parameters: the surface temperatures of the first to sixth rolls are set to 120℃, 110℃, 100℃, 100℃, 110℃, and 120℃ respectively; the speed ratio is adjusted to 1:1.5:3:3:1.5:1; the roll gaps are adjusted to 200μm, 100μm, 150μm, 100μm, and 200μm respectively; the bilateral pressure is 2T; and the current collector winding speed is 1m / min.

[0088] After the setup is complete, start the current collector unwinding device and the six-roller pressing equipment to manufacture the electrode sheet. After winding, the prepared solid electrode sheet can be obtained.

[0089] Comparative Example 1:

[0090] In Comparative Example 1, the electrode material was graphite, the conductive material was carbon black, and the binder was PTFE.

[0091] First, graphite, carbon black, and PTFE are mixed in a mass ratio of 95:3:2. During mixing, the graphite and carbon black are first stirred at 10 m / min for 10 minutes at room temperature. Then, the temperature is lowered to 15°C, and the PTFE material is added, and the mixture is stirred at 15 m / min for 10 minutes until homogeneous.

[0092] Then, the mixed material was stirred at high speed at 45 m / min and at 80°C for 4 min to fibrillate it, resulting in fibrillated powder.

[0093] Next, the fibrillated powder is subjected to fiber network reinforcement treatment. Fiber network reinforcement treatment can be achieved by stirring in a twin-screw extruder with a speed ratio of 1:1.4 for 60 minutes. Then, the fiber network reinforced powder is sieved through a 1 mm sieve to obtain powder particles with a particle size of 1 mm.

[0094] Finally, the powder particles are evenly added to the two feed ports of the six-roll press, and the six-roll press is configured according to the following target parameters:

[0095] The surface temperatures of the first to sixth rollers are set to 80℃, 80℃, 100℃, 100℃, 80℃, and 80℃ respectively. The speed ratio is adjusted to 1:1.1:1.2:1.2:1.1:1. The roller gaps are adjusted sequentially to 300μm, 150μm, 250μm, 150μm, and 300μm. The bilateral pressure is 3T, and the current collector winding speed is 2m / min.

[0096] After the setup is complete, start the current collector unwinding device and the six-roller pressing equipment to manufacture the electrode sheet. After winding, the prepared solid electrode sheet can be obtained.

[0097] Figure 5 This is a scanning electron microscope (SEM) image of a solid electrode sheet obtained using the parameters in Example 1, provided as an embodiment of this application. Figure 6 The image provided is a scanning electron microscope (SEM) image of a solid electrode sheet obtained using the parameters in Example 2, as an embodiment of this application. Figure 7 A physical image of a solid electrode sheet obtained using the parameters in Comparative Example 1, provided as an embodiment of this application.

[0098] refer to Figure 5 , Figure 6 and Figure 7 The solid electrode sheets prepared in Examples 1 and 2 have dense structures and strong bonding, exhibiting excellent electrical properties. However, the solid electrode sheet prepared in Comparative Example 1 suffers from problems such as surface powder shedding and electrode film breakage, rendering it unusable.

[0099] Therefore, the dry manufacturing method for solid electrode sheets provided in this application can effectively avoid problems such as electrode powder shedding, wrinkling and breakage, simplify the production process, and improve the mechanical and electrochemical properties of the electrode, which has great practical value.

[0100] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0101] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A dry manufacturing method for a solid electrode sheet, characterized in that, The method includes: Electrode material powder, conductive material powder and binder powder are mixed evenly in a preset ratio to obtain mixed material powder; The mixed material powder is subjected to fibrillation treatment under a first preset condition, so that the binder powder is softened and extended into filaments, and uniformly coated on the surface of the electrode material to obtain fibrillated powder. The fibrillated powder is subjected to fiber network reinforcement treatment and then sieved into uniform powder particles. The sieved powder particles are added to the feeding trough of the multi-roller pressing equipment. The multi-roller pressing equipment also includes a collector unwinding device and a collector winding device. The collector unwinding device is equipped with a collector and a collector preheating component. One end of the collector is connected to the unwinding device, and the other end is connected to the winding device. After the collector is heated to a preset temperature by the collector preheating component, it passes through the multi-roller pressing equipment under the traction of the unwinding device and the winding device. The multi-roller pressing device is configured with target parameters, and the sieved powder particles are rolled onto the current collector to obtain the solid electrode sheet.

2. The method according to claim 1, characterized in that, The multi-roller pressing equipment includes at least 6 rollers arranged side by side, the diameter of the rollers being 200mm-350mm and the width of the roller surface being 200mm-400mm, and the rollers being arranged side by side.

3. The method according to claim 2, characterized in that, The target parameters include: The temperature range of the roller surface is 80℃-150℃; The gap width between adjacent rollers ranges from 60 μm to 300 μm; The rolling pressure range is 2T-6T.

4. The method according to claim 3, characterized in that, The six rollers arranged side by side, from left to right, are the first roller, the second roller, the third roller, the fourth roller, the fifth roller, and the sixth roller. The target parameters also include: The first roller and the sixth roller rotate at the same speed but in opposite directions; The second roller and the fifth roller rotate at the same speed but in opposite directions; The third roller and the fourth roller rotate at the same speed but in opposite directions.

5. The method according to claim 4, characterized in that, The multi-roller pressing device includes a first feeding trough and a second feeding trough. The first feeding trough is disposed between the first roller and the second roller, and the second feeding trough is disposed between the fifth roller and the sixth roller. The step of pressing the sieved powder particles onto the current collector using the multi-roller pressing device includes: The powder particles in the first feeding trough are rolled using the first roller and the second roller to obtain the first electrode film formed for the first time. The temperature difference between the roller surfaces of the first roller and the second roller is in the range of 0-10℃, and the roller gap distance between the first roller and the second roller is in the range of 100-300μm. The powder particles in the second feeding trough are rolled using the fifth roller and the sixth roller to obtain a second electrode film formed for the first time. The temperature difference between the roller surfaces of the fifth roller and the sixth roller is in the range of 0-10℃, and the roller gap distance between the fifth roller and the sixth roller is in the range of 100-300μm. The first electrode film initially formed is thinned using the second roller and the third roller to obtain a thinned first electrode film. The temperature difference between the roller surfaces of the second roller and the third roller is in the range of 0-20℃, and the roller gap distance between the second roller and the third roller is in the range of 50-150μm. The second electrode film initially formed is thinned using the fourth roller and the fifth roller to obtain a thinned second electrode film. The temperature difference between the roller surfaces of the fourth roller and the fifth roller is in the range of 0-20℃, and the gap between the rollers of the fourth roller and the fifth roller is in the range of 50-150μm. The current collector passes through the roll gap between the third and fourth rollers, and the third and fourth rollers roll the thinned first electrode film onto one side of the current collector and the thinned second electrode film onto the other side of the current collector. The roller surface temperatures of the third and fourth rollers are the same or similar, and the roll gap distance between the third and fourth rollers is determined based on the roll gap distance between the second and third rollers.

6. The method according to claim 5, characterized in that, The method further includes: The roll gap distance between the third roller and the fourth roller is: the roll gap distance between the second roller and the third roller multiplied by 2, minus 50μm.

7. The method according to claim 1, characterized in that, The current collector preheating component includes two heating modules arranged opposite to each other, and the heating module is a laser heating component or an infrared heating component; When the current collector is pulled through the current collector preheating component by the unwinding device, the current collector is preheated to the preset temperature of 50-100℃ by the two heating modules.

8. The method according to claim 1, characterized in that, The binder powder is polytetrafluoroethylene (PTFE), and the particle size of the PTFE ranges from 50 to 200 μm.

9. The method according to any one of claims 1-8, characterized in that, The first preset conditions include: The stirring speed range for the fibrillation treatment is 30 to 50 meters per minute. The stirring temperature range for the fibrillation treatment is 70℃-100℃; The stirring time for the fibrillation treatment ranges from 3 to 5 minutes.

10. The method according to any one of claims 1-8, characterized in that, The fiber network strengthening process includes: extruding and shearing the fibrillated powder using a twin-screw extruder; The sieving process to obtain uniform powder particles includes: sieving the powder that has undergone the fiber network reinforcement treatment through a sieve with a pore size of 0.5 mm-1 mm to obtain powder particles with a particle size of 0.1 mm-1 mm.

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