Electrode preparation method, electrode and battery
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- MICROVAST POWER SYST CO LTD
- Filing Date
- 2024-02-26
- Publication Date
- 2026-05-12
AI Technical Summary
The use of organic solvents in the wet coating process of lithium-ion batteries leads to equipment energy consumption loss and environmental pollution, and the crushing of active material particles in the dry coating process leads to a decrease in battery capacity.
The dry coating process is used to mix the electrode active material, conductive agent and fibrotic binder to avoid solvent use and fibrotic treatment of the active material. The binder fiber is prepared through electrospinning process, and the mixed material is directly coated on the carrier.
Reduce equipment energy consumption loss, improve environmental friendliness, prevent active material particles from breaking, and improve battery capacity.
Smart Images
Figure CN122029639A_ABST
Abstract
Description
Electrode preparation method, electrode and battery Technical Field
[0001] The present application relates to the technical field of lithium-ion battery manufacturing, and in particular to an electrode preparation method, an electrode, and a battery. Background Art
[0002] Lithium-ion batteries have the advantages of high capacity, high energy density, low self-discharge rate and environmental protection. They are widely used in electric vehicles, portable electronic devices and large-scale energy storage systems.
[0003] Lithium-ion battery electrode manufacturing involves two processes: wet coating and dry coating. The wet coating process involves uniformly mixing the electrode active material, conductive agent, binder, and solvent (such as the organic solvent NMP) to create a mixed slurry, which is then applied to the current collector. The dry coating process, on the other hand, involves directly mixing the electrode active material, conductive agent, and binder to create a mixed material without the use of solvents. The mixed material is evenly dispersed and then applied to the current collector. Alternatively, the mixed material is fiberized before being applied to the current collector. Technical issues
[0004] In the wet coating process, the mixed slurry contains organic solvents such as NMP, which need to be baked out. However, the baking stage will cause large energy losses to the equipment. At the same time, NMP is a toxic solvent and its large-scale use is very unfriendly to the environment.
[0005] In the dry coating process, the electrode active material, conductive agent and binder are first mixed to form a mixed material, and then the mixed material is prepared into mixed material fibers. In this process, the electrode active material will be damaged, causing the active material particles to break, which in turn leads to a decrease in battery capacity. Technical Solutions
[0006] The present application provides a method for preparing an electrode, comprising the following steps:
[0007] S1, adding the electrode active material, the conductive agent and the binder fiber into a container and stirring to form a mixed material;
[0008] S2. Placing the mixed material on a carrier to form an electrode.
[0009] As an embodiment, in the above step S1, the mass fraction of the electrode active material in the mixed material is 80wt%-98wt%, the mass fraction of the conductive agent is 1wt%-10wt%, and the mass fraction of the binder fiber is 1wt%-10wt%.
[0010] As an embodiment, in the above step S1, the electrode active material is a positive electrode active material, and the positive electrode active material is one or more of lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, ternary nickel cobalt lithium manganese oxide and lithium iron phosphate.
[0011] As an embodiment, in the above step S1, the electrode active material is a negative electrode active material, and the negative electrode active material is one or more of graphite, silicon, silicon oxide, lithium-silicon alloy and metallic lithium powder.
[0012] As an embodiment, in the above step S1, the conductive agent is one or more of acetylene black, Super-P (SP), carbon nanotubes, graphite and graphene.
[0013] As an embodiment, in the above step S1, the binder fiber is one or more of PTFE, PVDF, SBR, CMC, PP, PE, PI and EVA.
[0014] As an embodiment, in the above step S1, the electrode active material and the conductive agent are first placed in the container, and then the binder fiber is added into the container and stirred to form the mixed material.
[0015] As an embodiment, in the above step S1, the electrode active material and the conductive agent are first placed in the container and stirred once, and then the binder fiber is added to the container, and a second stirring is performed during the process of adding the binder fiber to the container to form the mixed material.
[0016] As an embodiment, in the above step S1, after the binder fibers are completely added into the container, stirring is further performed three times.
[0017] As an embodiment, in the above step S1, the method for preparing the binder fiber includes the following steps:
[0018] The binder is dispersed in a solvent to prepare a binder spinning solution; and then the binder spinning solution is subjected to an electrostatic spinning process to form the binder fiber.
[0019] As an embodiment, the solid content of the binder spinning solution is 5%-30%.
[0020] The present application also provides an electrode, which is prepared using the electrode preparation method described above.
[0021] The present application also provides a battery comprising the above-mentioned electrode. Beneficial effects
[0022] The electrode preparation method provided in this application, because the mixed material does not contain solvent, does not require baking of the electrode (i.e., a dry coating process is used), thus reducing equipment energy loss and improving environmental friendliness. Furthermore, this application mixes a fiberized binder (i.e., binder fiber) with the electrode active material and the conductive agent, eliminating the need for fiberization of the electrode active material. This avoids the problem of active material particle breakage in the mixed material used during coating, preventing the reduction in battery capacity caused by active material particle breakage, and the binder used is universally applicable. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG1 is a SEM image of the surface of the electrode prepared in Example 1 of the present application.
[0024] FIG2 is a SEM image of the surface of the electrode prepared in Comparative Example 1 of the present application.
[0025] FIG3 is a schematic diagram of the preparation process of the mixed materials in Examples 1 and 2 of the present application. Modes for Carrying Out the Invention
[0026] The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.
[0027] An embodiment of the present application provides a method for preparing an electrode, which comprises the following steps:
[0028] S1. Adding electrode active materials, conductive agents and binder fibers into a container and stirring to form a mixed material; wherein the stirring time is 1-120 minutes, or 30-60 minutes.
[0029] S2. Disposing the above-mentioned mixed material on a carrier (specifically, the mixed material can be disposed on the carrier by coating) to form an electrode.
[0030] Specifically, in step S1 of the above-mentioned electrode preparation method, the present application mixes the electrode active material and the conductive agent with the binder fiber to form a mixed material; instead of mixing the electrode active material, the conductive agent and the binder to form a mixed material and then preparing the mixed material fiber. This is to avoid damage to the active material during the fiberization process and prevent the active material particles from being broken and causing a decrease in battery capacity (especially the positive electrode active material. When the positive electrode active material is destroyed, its impact on the battery capacity is greater).
[0031] As an embodiment, in the above step S1, the electrode active material and the conductive agent are first placed in a container, and then the binder fiber is added to the container and stirred to form a mixed material. The stirring time is 1-120 minutes, or 30-60 minutes.
[0032] As another embodiment, in the above step S1, the electrode active material and the conductive agent are first placed in a container and stirred once, and then the binder fiber is added to the container, and a second stirring is performed during the process of adding the binder fiber to the container to form a mixed material. Specifically, the time of the first stirring is 1-120 minutes, or 30-60 minutes. The time of the second stirring is determined by the amount of binder fiber added and the addition speed. After the binder fiber is completely added to the container, the second stirring is stopped. As an embodiment, after the binder fiber is completely added to the container, three stirrings are performed (the third stirring indicates that the binder fiber has been completely added to the container), and the time of the three stirrings is 1-120 minutes, or 60-100 minutes.
[0033] As an embodiment, the carrier is a current collector.
[0034] As an embodiment, the binder fiber in the above-mentioned electrode preparation method is a modified compound of one or more of PTFE (polytetrafluoroethylene), PVDF (polyvinylidene fluoride), SBR (styrene-butadiene rubber), CMC (sodium carboxymethyl cellulose), PP (polypropylene), PE (polyethylene), PI (polyimide), and EVA (ethylene vinyl acetate).
[0035] As an embodiment, when the prepared electrode is a positive electrode sheet, the carrier can be aluminum foil, and the electrode active material in the above-mentioned electrode preparation method is a positive electrode active substance, which is a modified compound of one or more of lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, ternary nickel cobalt lithium manganese oxide, and lithium iron phosphate.
[0036] As an embodiment, when the prepared electrode is a negative electrode sheet, the carrier can be copper foil, and the electrode active material in the above-mentioned electrode preparation method is a negative electrode active substance, which is a modified compound of one or more of graphite, silicon, silicon oxide, lithium silicon alloy, and metallic lithium powder.
[0037] As an embodiment, the conductive agent in the above-mentioned electrode preparation method is a modified compound of one or more of acetylene black, Super-P (small particle conductive carbon black), carbon nanotubes, graphite, and graphene.
[0038] As an embodiment, in the mixed material of the above-mentioned electrode preparation method, the mass fraction of the electrode active material is 80wt%-98wt%, the mass fraction of the conductive agent is 1wt%-10wt%, and the mass fraction of the binder fiber is 1wt%-10wt%.
[0039] As shown in FIG3 , as an embodiment, the container in the above-mentioned electrode preparation method is a stirring barrel.
[0040] As an embodiment, the stirring linear speed of the container in the above-mentioned electrode preparation method is 1-60 m / s; or 1-30 m / s.
[0041] As an embodiment, the tilt angle of the container in the above-mentioned electrode preparation method can be adjusted, and the container can be rotated (ie, rotated), thereby improving the mixing uniformity of the electrode active material, the conductive agent, and the binder fiber.
[0042] As shown in FIG3 , as an embodiment, a stirring paddle is provided in the container in the above-mentioned electrode preparation method. The stirring paddle can be any type of single / double spiral, straight, three-leaf, or dispersed disk.
[0043] As an embodiment, in the above step S1, the method for preparing the binder fiber includes the following steps:
[0044] The binder is dispersed in a solvent to prepare a binder spinning solution; the binder spinning solution is then formed into binder fibers through an electrostatic spinning process.
[0045] Specifically, the electrospinning process involves dispersing a binder in a solvent to prepare a binder spinning solution; placing the binder spinning solution in a high-voltage electric field, where the charged spinning solution forms a jet stream under the action of the electric field; during the jet stream's ejection, the solvent evaporates, forming binder fibers on a receiving device. The electrospinning apparatus used in this process includes a propulsion pump, a syringe, a high-voltage power supply, and a receiving device. Under the action of the electric field created by the high-voltage power supply, the charged binder spinning solution accelerates the syringe needle in the electrospinning apparatus, overcoming surface tension to form a jet stream. During the jet stream's ejection, the solvent evaporates, ultimately landing on the receiving device to form binder fibers. The use of a binder spinning solution for electrospinning, rather than a binder melt, is due to the high equipment requirements for preparing a binder melt, and some binders are not suitable for melt preparation. Preparing a binder spinning solution, on the other hand, is simpler and requires less equipment. All commonly used binders can be used to prepare a binder spinning solution, making it universally applicable.
[0046] As an embodiment, in the above-mentioned method for preparing the binder fiber, the solid content of the binder spinning solution is 5%-30%, and the solid content of the binder spinning solution = total mass of the binder / (total mass of the binder + total mass of the solvent) × 100%.
[0047] Specifically, the amount of solvent used to prepare the binder spinning solution is small, the solid content of the binder spinning solution is high, and the solvent is evaporated during the electrospinning process, and drying is completed directly without the need for the electrode baking process in the conventional process, thereby reducing equipment energy consumption losses; at the same time, a small amount of organic solvent is used to prepare the binder spinning solution, and the amount of organic solvent used is small, making the electrode preparation process more environmentally friendly.
[0048] An embodiment of the present application also provides an electrode prepared by the above-mentioned electrode preparation method.
[0049] An embodiment of the present application further provides a battery comprising the above-mentioned electrode, wherein the above-mentioned electrode is a positive electrode sheet and / or a negative electrode sheet.
[0050] The electrode preparation method provided in this application, because the mixed material does not contain solvent, does not require baking of the electrode (i.e., a dry coating process is used), thus reducing equipment energy loss and improving environmental friendliness. Furthermore, this application mixes a fiberized binder (i.e., binder fiber) with the electrode active material and the conductive agent, eliminating the need for fiberization of the electrode active material. This avoids the problem of active material particle breakage in the mixed material used during coating, preventing the reduction in battery capacity caused by active material particle breakage, and the binder used is universally applicable.
[0051] Example 1
[0052] A spinning solution with a solid content of 18.2% was prepared by combining 0.2g PTFE and 0.9g NMP. The solution was then added to an electrospinning apparatus to prepare PTFE binder fibers. Simultaneously, 9.6g of the positive electrode material NCM and 0.2g of the conductive agent SP were added to a stirring barrel and stirred at a rate of 10m / s. While stirring, the PTFE binder fibers were slowly extruded into the barrel at a rate of 5μm / min. After all the PTFE binder fibers were extruded, the barrel continued stirring for 60 minutes. The stirring was stopped to obtain a mixed material. The mixed material in the barrel was spread evenly on a current collector and hot-pressed to form a positive electrode sheet.
[0053] Example 2
[0054] A spinning solution with a solid content of 20% was prepared by combining 0.075g of CMC, 0.125g of SBR, and 0.8g of deionized water. This solution was then added to an electrospinning apparatus to prepare CMC and SBR binder fibers. Simultaneously, 9.5g of graphite anode material and 0.2g of conductive agent (SP) were added to a stirring barrel and stirred at a rate of 15m / s. While stirring, the binder fibers were slowly extruded into the barrel at a rate of 5μm / min. After all the binder fibers were extruded, the barrel continued stirring for 80 minutes. The stirring was then stopped to obtain a mixed material. The mixed material in the barrel was spread evenly on a current collector and hot-pressed to form a negative electrode sheet.
[0055] 3 is a schematic diagram of the preparation process of the mixed material in Examples 1 and 2 of the present application.
[0056] Comparative Example 1
[0057] The types and contents of the main materials and conductive agent were consistent with those in Example 1. 9.6 g of the positive electrode material NCM and 0.2 g of the conductive agent SP were mixed and stirred for 30 minutes, and PTFE was added and stirred for 10 minutes. The mixture of the main material NCM, the conductive agent SP, and the PTFE was then subjected to a jet milling process to fiberize the PTFE and draw it into wires to obtain a mixed material. The mixed material was then spread on a current collector and hot-pressed to prepare a positive electrode sheet.
[0058] Figure 1 is a SEM image of the electrode surface prepared in Example 1, and Figure 2 is a SEM image of the electrode surface prepared in Comparative Example 1. Figure 1 shows that the positive electrode material NCM spherical particles of Example 1 are well maintained, while Figure 2 shows that the positive electrode material NCM spherical particles in Comparative Example 1 are essentially broken into small particles, which can affect the overall electrochemical performance of the battery.
[0059] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.
Claims
1. A method for preparing an electrode, characterized in that, It includes the following steps: S1. Add the electrode active material, conductive agent, and binder fiber into a container and stir to form a mixed material; S2. Set the mixed material on a carrier to form an electrode.
2. The electrode preparation method according to claim 1, wherein In the above step S1, the mass fraction of the electrode active material in the mixed material is 80wt%-98wt%, the mass fraction of the conductive agent is 1wt%-10wt%, and the mass fraction of the binder fiber is 1wt%-10wt%.
3. The electrode preparation method according to claim 1, characterized in that, In the above step S1, the electrode active material is a positive electrode active substance, and the positive electrode active substance is one or more of lithium cobaltate, lithium manganate, lithium nickelate, ternary nickel cobalt manganese lithium, and lithium iron phosphate.
4. The electrode preparation method according to claim 1, characterized in that, In the above step S1, the electrode active material is a negative electrode active substance, and the negative electrode active substance is one or more of graphite, silicon, silicon monoxide, lithium silicon alloy, and lithium metal powder.
5. The electrode preparation method according to claim 1, characterized in that, In the above step S1, the conductive agent is one or more of acetylene black, Super-P, carbon nanotubes, graphite, and graphene.
6. The electrode preparation method according to claim 1, characterized in that, In the above step S1, the binder fiber is one or more of PTFE, PVDF, SBR, CMC, PP, PE, PI, and EVA.
7. The electrode preparation method according to claim 1, characterized in that, In the above step S1, first place the electrode active material and the conductive agent in the container, and then add the binder fiber into the container for stirring to form the mixed material.
8. The electrode preparation method according to claim 1, wherein, In the above step S1, first place the electrode active material and the conductive agent in the container for a first stirring, then add the binder fiber into the container, and perform a second stirring during the process of adding the binder fiber into the container to form the mixed material.
9. The electrode preparation method according to claim 8, characterized in that, In the above step S1, after the binder fiber is completely added into the container, a third stirring is also performed.
10. The method for preparing an electrode according to any one of claims 1-9, characterized in that, In the above step S1, the preparation method of the binder fiber includes the following steps: Disperse the binder in a solvent to prepare a binder spinning solution; then form the binder fiber from the binder spinning solution through an electrospinning process.
11. The electrode preparation method according to claim 10, characterized in that, The solid content of the binder spinning solution is 5%-30%.
12. An electrode, characterized in that, It is prepared by using the electrode preparation method described in any one of claims 1-11.
13. A battery, characterized in that, It includes the electrode described in claim 12.