CN116154110A - Lithium ion battery electrode slice and dry preparation method thereof - Google Patents

Lithium ion battery electrode slice and dry preparation method thereof Download PDF

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Publication number
CN116154110A
CN116154110A CN202111399152.XA CN202111399152A CN116154110A CN 116154110 A CN116154110 A CN 116154110A CN 202111399152 A CN202111399152 A CN 202111399152A CN 116154110 A CN116154110 A CN 116154110A
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mixing
hot
lithium ion
dry powder
ion battery
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龙超
张中春
彭建林
唐雪姣
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Shenzhen Motil Technology Co ltd
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Shenzhen Motil Technology Co ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

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  • General Chemical & Material Sciences (AREA)
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Abstract

The invention belongs to the technical field of lithium battery manufacturing, and particularly relates to a lithium ion battery electrode slice and a dry method preparation method thereof. The dry process provided by the invention completely removes the solvent, saves cost, improves efficiency, and is beneficial to environmental protection; the method adopts the primary mixing, crushing and high-temperature re-mixing hot-pressing processes, and the binding agent is fully fibrillated inside the electrode to form a three-dimensional net structure through the cooperation of the steps, so that the connection between the active substance and the conductive agent is tighter, on one hand, the strength of the electrode plate is improved, and on the other hand, the conductivity is improved, thereby further improving the stability, the cycle life, the charge-discharge performance and the power output capability of the electrode plate.

Description

Lithium ion battery electrode slice and dry preparation method thereof
Technical Field
The invention relates to the technical field of lithium battery manufacturing, in particular to a lithium ion battery electrode slice and a dry method preparation method thereof.
Background
Lithium batteries are a type of battery using a nonaqueous electrolyte solution with lithium metal or a lithium alloy as a positive/negative electrode material. The chemical characteristics of lithium metal are very active, so that the processing, storage and use of lithium metal have very high requirements on environment. With the development of science and technology, lithium batteries have become the mainstream. It is well known that electrodes are the basis of batteries and that the preparation of electrodes is also a vital part of the production of batteries. With the wide application of lithium ion batteries in consumer electronics, transportation and aerospace military industries, the development of low-cost and high-efficiency electrode preparation technology has become a necessary trend.
At present, the pole piece of the lithium ion battery is manufactured by adopting a wet pulping and coating mode basically, the process is complex, and the cost is high. And the organic solvent adopted in the positive electrode pulping has toxicity and is difficult to recycle. The prior patent document discloses a lithium battery and a dry preparation method and application thereof, wherein the lithium battery is mainly prepared by mixing a conductive agent and a binder, coating the mixture on a foil to form a first coating layer, mixing an electrode material with a second conductive agent and a second binder according to a certain proportion to obtain electrode slurry, coating the electrode slurry on the first coating layer to form a second coating layer, and finally hot-pressing the first coating layer and the second coating layer at a certain temperature and pressure to obtain the electrode of the lithium battery.
However, the technique disclosed in the above document is nominally to prepare an electrode of a lithium battery by a dry method, but in practice, the preparation of the first coating layer is wet coating, and the introduction of a solvent is not a strictly speaking dry process; in addition, the mixing methods disclosed in the above documents cannot uniformly mix the components due to the differences in particle size and density of the active material, the conductive agent and the binder, and adversely affect the physical strength and electrical properties of the pole piece.
Disclosure of Invention
Therefore, the invention aims to overcome the defects that the physical strength and the electrical property of the electrode sheet are affected by the uneven material mixing and the like because a solvent is needed to be adopted in the preparation of the electrode in the prior art, and further provides the lithium ion battery electrode sheet and the dry preparation method thereof.
Therefore, the invention provides the following technical scheme:
the invention provides a dry preparation method of a lithium ion battery electrode slice, which comprises the following steps:
primary mixing: mixing the conductive agent and the binder, and carrying out jet milling under the pressure of 0.5-0.8MPa to obtain a ground material;
remixing: mixing the obtained crushed material with active substances at 50-80 ℃ to obtain a mixture;
coating: and spraying the obtained mixture onto a current collector, hot-pressing to obtain a single-sided dry electrode, and spraying and hot-pressing the other side of the current collector again to obtain the double-sided composite pole piece.
Optionally, in the primary mixing step, the mixing time is 15-60min, and the mixing rotating speed is 50-200r/min;
in the remixing step, the mixing time is 30-90min, and the mixing rotating speed is 20-100r/min;
the primary mixing step may be performed using a high speed mixer.
Optionally, the jet milling is performed by a jet mill, and the air inlet pressure is 0.3-0.7MPa;
optionally, the remixing step adopts a double-motion mixer, the rotating speed of a charging barrel is 10-30r/min, and the rotating speed of a blade is 20-75r/min. The conductive agent and the binder are mixed with the active material in a double-motion mixing mode, so that the powder can be mixed more uniformly.
Optionally, the hot pressing temperature is 200-250 ℃, the pressure is 15-40Mpa, and the speed is 0.5-2m/min.
Optionally, the mass ratio of the active substance, the conductive agent and the binder is (85-95): (1-5): (4-10).
Optionally, the active material is a positive electrode active material or a negative electrode active material.
Optionally, when the active material is a negative electrode active material, the steps of primary mixing and remixing are: mixing active material, conductive agent and binder at 50-80deg.C, and jet milling under 0.5-0.8MPa to obtain mixture.
Alternatively, when the active material is a negative electrode active material, the mixing time is 30 to 90 minutes and the mixing speed is 20 to 100r/min.
Optionally, the single-sided spraying thickness of the mixture is 0.5-2mm.
Optionally, the conductive agent is at least one of ketjen black, conductive carbon black Super P and acetylene black;
the binder is polytetrafluoroethylene and/or polyvinylidene fluoride;
the positive electrode active material is LiMn 2 O 4 ，LiCoO 2 ，LiFePO 4 ，LiNi x Co y Mn z O 2 (x+y+z＝1，0<x<1，0<y<1，0<z<1)、LiNi x Co y Al z O 2 (x+y+z＝1，0<x<1，0<y<1，0<z<1) At least one of the compounds;
the negative electrode active material is at least one of graphite, hard carbon material, soft carbon material and silicon-carbon composite material.
Optionally, the hard carbon material is at least one of resin carbon, organic polymer pyrolytic carbon and carbon black; the soft carbon material is petroleum coke, needle coke and carbon microsphere; the silicon-carbon composite material is at least one of carbon-coated nano silicon and silicon oxide-carbon composite material.
The invention also provides a lithium ion battery electrode slice prepared by the method.
The technical scheme of the invention has the following advantages:
1. the invention provides a dry preparation method of a lithium ion battery electrode slice, which comprises the following steps: primary mixing: mixing the conductive agent and the binder, and carrying out jet milling under the pressure of 0.5-0.8MPa to obtain a ground material; remixing: mixing the obtained crushed material with active substances at 50-80 ℃ to obtain a mixture; coating: and spraying the obtained mixture onto a current collector, hot-pressing to obtain a single-sided dry electrode, and spraying and hot-pressing the other side of the current collector again to obtain the double-sided composite pole piece. The dry process provided by the invention completely removes the solvent, saves cost, improves efficiency, and is beneficial to environmental protection; the method adopts the primary mixing, crushing and high-temperature re-mixing hot-pressing processes, and the binding agent is fully fibrillated inside the electrode to form a three-dimensional net structure through the cooperation of the steps, so that the connection between the active substance and the conductive agent is tighter, on one hand, the strength of the electrode plate is improved, and on the other hand, the conductivity is improved, thereby further improving the stability, the cycle life, the charge-discharge performance and the power output capability of the electrode plate. Specifically, the size of the conductive agent and the binder is refined and uniform by mixing the binder and the conductive agent with similar density and size particles at high speed; the mixture of the conductive agent and the binder is crushed in an airflow crushing mode, the binder is fibrillated to form a three-dimensional net structure, active material particles are tightly connected, the deintercalation of lithium ions is facilitated, the conductivity is improved, the stability and the cycle life of the electrode are improved, and the charge and discharge efficiency and the output of power can be improved. The high-temperature remixing can realize the preactivation of the powder, so that the powder is more stable in the spraying process. The electrode plate prepared by adopting the dry method technology has the advantages that the compaction density is improved, so that the capacity and the energy density of the battery are improved.
2. According to the method for preparing the lithium ion battery electrode slice by the dry method, when the active substance is the negative electrode active substance, the mixing process of the negative electrode material can be carried out by combining the primary mixing and remixing steps because the particle size and density of the negative electrode active substance, the conductive agent and the binder are not greatly different, so that the process is further simplified.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic illustration of the coating step in example 1 of the present invention.
Wherein, 1, a spray gun; 2. a mixture; 3. a coating current collector; 4. a heating roller; 5. electrode plate.
Detailed Description
The following examples are provided for a better understanding of the present invention and are not limited to the preferred embodiments described herein, but are not intended to limit the scope of the invention, any product which is the same or similar to the present invention, whether in light of the present teachings or in combination with other prior art features, falls within the scope of the present invention.
The specific experimental procedures or conditions are not noted in the examples and may be followed by the operations or conditions of conventional experimental procedures described in the literature in this field. The reagents or apparatus used were conventional reagent products commercially available without the manufacturer's knowledge.
To facilitate comparison between the data, the sources of raw materials used in the following examples and comparative examples of the present invention are as follows:
polytetrafluoroethylene (PTFE): a kemu, 60X;
keqin black: lion king, ECP600JD;
graphite: bei Terui, GSN;
conductive carbon black Super P: SUPER high, SUPER Li;
polyvinylidene fluoride: acarma, HSV900;
pyrolysis of organic polymers hard carbon: bei Terui, BHC-240;
acetylene black: DENKA BLACK Li, japanese electric chemistry;
petroleum coke soft carbon: bei Terui, BSC-1;
silica-carbon composite: bei Terui, S420-2A.
Example 1
The embodiment provides a dry method for preparing a lithium ion battery electrode slice, which comprises the following steps:
preparing a positive electrode plate:
placing 60g of Polytetrafluoroethylene (PTFE) and 20g of Keqin black into a high-speed mixer for primary mixing, and fully mixing for 30min at a mixing speed of 100r/min; then use the gasCrushing by a fluid crusher to obtain crushed materials, wherein the air inlet pressure is 0.4MPa and the crushing pressure is 0.6MPa; then the crushed material and 920g of LiNi 0.5 Co 0.2 Mn 0.3 O 2 Placing the mixture into a double-motion mixer for mixing and stirring, wherein the mixing time is 60min, the rotating speed of a charging basket is 20r/min, the rotating speed of a blade is 50r/min, and the mixing temperature is 65 ℃ to obtain a final dry powder mixture 2 in a fluffy state; and finally, placing the dry powder mixture 2 into a spray gun 1, spraying a dry powder coating with the thickness of 0.8mm on the moving coating current collector 3 by adopting a spraying method, and then tightly compounding the dry powder coating and the coating current collector 3 by adopting a hot pressing mode of a heating roller 4, wherein the hot pressing temperature is 230 ℃, the hot pressing pressure is 30MPa, and the speed is 1.2m/min, so as to obtain the single-sided positive electrode sheet 5. And then, the same method is used for compounding a dry powder coating on the other surface of the coating current collector, and finally the double-sided composite positive plate is obtained.
Preparing a negative electrode plate:
taking 920g of graphite, 60g of Polytetrafluoroethylene (PTFE) and 20g of Keqin black, placing the graphite, the PTFE and the Keqin black in a double-motion mixer for primary mixing for 30min, wherein the rotation speed of a charging basket is 20r/min, the rotation speed of a blade is 50r/min, and the mixing temperature is 65 ℃; then using an air flow pulverizer to pulverize, wherein the air inlet pressure is 0.4MPa, and the pulverizing pressure is 0.6MPa, so as to obtain a fluffy negative electrode dry powder mixture 2; and finally, placing the dry powder mixture 2 into a spray gun 1, spraying a dry powder coating with the thickness of 1.0mm on the moving coating current collector 3 by adopting a spraying method, and then tightly compounding the dry powder coating and the coating current collector 3 by adopting a hot pressing mode of a heating roller 4, wherein the hot pressing temperature is 230 ℃, the hot pressing pressure is 30MPa, and the hot pressing speed is 1.2m/min, so as to obtain the single-sided negative electrode plate 5. And then, the same method is used for compounding a dry powder coating on the other surface of the coating current collector, and finally the double-sided composite negative plate is obtained.
Example 2
The embodiment provides a dry method for preparing a lithium ion battery electrode slice, which comprises the following steps:
preparing a positive electrode plate:
mixing 45g Polytetrafluoroethylene (PTFE) and 15g ketjen black at high speedPrimary mixing is carried out by a machine, the mixing is carried out fully for 30min, and the mixing speed is 100r/min; then crushing by using an air flow crusher to obtain crushed materials, wherein the air inlet pressure is 0.4MPa, and the crushing pressure is 0.6MPa; then the crushed material and 940g of LiNi 0.5 Co 0.2 Mn 0.3 O 2 Placing the mixture into a double-motion mixer for mixing and stirring, wherein the mixing time is 60min, the rotating speed of a charging basket is 20r/min, the rotating speed of a blade is 50r/min, and the mixing temperature is 65 ℃ to obtain a final dry powder mixture in a fluffy state; and finally, placing the dry powder mixture into a special spray gun, spraying a dry powder coating with the thickness of 0.5mm on the moving coating current collector by adopting a spraying method, and then tightly compounding the dry powder coating and the coating current collector by adopting a heating roller hot-pressing mode, wherein the hot-pressing temperature is 230 ℃, the hot-pressing pressure is 15MPa, and the hot-pressing speed is 0.5m/min, so as to obtain the single-sided positive electrode plate. And then, the same method is used for compounding a dry powder coating on the other surface of the coating current collector, and finally the double-sided composite positive plate is obtained.
Preparing a negative electrode plate:
940g of graphite, 45g of Polytetrafluoroethylene (PTFE) and 15g of Keqin black are placed in a double-motion mixer to be primarily mixed, the mixing time is 30min, the rotation speed of a charging basket is 20r/min, the rotation speed of a blade is 50r/min, and the mixing temperature is 65 ℃; then using an air flow pulverizer to pulverize, wherein the air inlet pressure is 0.4MPa, and the pulverizing pressure is 0.6MPa, so as to obtain a fluffy negative electrode dry powder mixture; and finally, placing the dry powder mixture into a special spray gun, spraying a dry powder coating with the thickness of 0.5mm on the moving coating current collector by adopting a spraying method, and then tightly compounding the dry powder coating and the coating current collector by adopting a heating roller hot-pressing mode, wherein the hot-pressing temperature is 230 ℃, the hot-pressing pressure is 15MPa, and the hot-pressing speed is 0.5m/min, so as to obtain the single-sided negative electrode plate. And then, the same method is used for compounding a dry powder coating on the other surface of the coating current collector, and finally the double-sided composite negative plate is obtained.
Example 3
The embodiment provides a dry method for preparing a lithium ion battery electrode slice, which comprises the following steps:
preparing a positive electrode plate:
placing 40g of Polytetrafluoroethylene (PTFE) and 10g of Keqin black into a high-speed mixer for primary mixing, and fully mixing for 30min at a mixing speed of 80r/min; then crushing by using an air flow crusher to obtain crushed materials, wherein the air inlet pressure is 0.4MPa, and the crushing pressure is 0.6MPa; then the crushed material and 950g of LiNi 0.5 Co 0.2 Mn 0.3 O 2 Placing the mixture into a double-motion mixer for mixing and stirring, wherein the mixing time is 90min, the rotating speed of a charging basket is 20r/min, the rotating speed of a blade is 50r/min, and the mixing temperature is 65 ℃ to obtain a final dry powder mixture in a fluffy state; and finally, placing the dry powder mixture into a special spray gun, spraying a dry powder coating with the thickness of 2mm on the moving coating current collector by adopting a spraying method, and then tightly compounding the dry powder coating and the coating current collector by adopting a heating roller hot-pressing mode, wherein the hot-pressing temperature is 230 ℃, the hot-pressing pressure is 40MPa, and the hot-pressing speed is 2m/min, so as to obtain the single-sided positive electrode plate. And then, the same method is used for compounding a dry powder coating on the other surface of the coating current collector, and finally the double-sided composite positive plate is obtained.
Preparing a negative electrode plate:
placing 950g of graphite, 40g of Polytetrafluoroethylene (PTFE) and 10g of Keqin black into a double-motion mixer for primary mixing, fully mixing for 30min, wherein the rotation speed of a charging basket is 20r/min, the rotation speed of a blade is 50r/min, and the mixing temperature is 65 ℃; then using an air flow pulverizer to pulverize to obtain pulverized materials, wherein the air inlet pressure is 0.4MPa, and the pulverizing pressure is 0.6MPa, so as to obtain a fluffy negative electrode dry powder mixture; and finally, placing the dry powder mixture into a special spray gun, spraying a dry powder coating with the thickness of 2mm on the moving coating current collector by adopting a spraying method, and then tightly compounding the dry powder coating and the coating current collector by adopting a heating roller hot-pressing mode, wherein the hot-pressing temperature is 230 ℃, the hot-pressing pressure is 40MPa, and the hot-pressing speed is 2m/min, so as to obtain the single-sided negative electrode plate. And then, the same method is used for compounding a dry powder coating on the other surface of the coating current collector, and finally the double-sided composite negative plate is obtained.
Example 4
The embodiment provides a dry method for preparing a lithium ion battery electrode slice, which comprises the following steps:
preparing a positive electrode plate:
placing 40g of Polytetrafluoroethylene (PTFE) and 10g of Keqin black into a high-speed mixer for primary mixing, and fully mixing for 30min at a mixing speed of 80r/min; then crushing by using an air flow crusher to obtain crushed materials, wherein the air inlet pressure is 0.5MPa, and the crushing pressure is 0.7MPa; then the crushed material and 950g of LiNi 0.5 Co 0.2 Mn 0.3 O 2 Placing the mixture into a double-motion mixer for mixing and stirring, wherein the mixing time is 90min, the rotating speed of a charging basket is 20r/min, the rotating speed of a blade is 50r/min, and the mixing temperature is 65 ℃ to obtain a final dry powder mixture in a fluffy state; and finally, placing the dry powder mixture into a special spray gun, spraying a dry powder coating with the thickness of 0.8mm on the moving coating current collector by adopting a spraying method, and then tightly compounding the dry powder coating and the coating current collector by adopting a heating roller hot-pressing mode, wherein the hot-pressing temperature is 230 ℃, the hot-pressing pressure is 30MPa, and the hot-pressing speed is 1.2m/min, so as to obtain the single-sided positive electrode plate. And then, the same method is used for compounding a dry powder coating on the other surface of the coating current collector, and finally the double-sided composite positive plate is obtained.
Preparing a negative electrode plate:
placing 950g of graphite, 40g of Polytetrafluoroethylene (PTFE) and 10g of Keqin black into a double-motion mixer for primary mixing, fully mixing for 30min, wherein the rotation speed of a charging basket is 20r/min, the rotation speed of a blade is 50r/min, and the mixing temperature is 65 ℃; then using an air flow pulverizer to pulverize, wherein the air inlet pressure is 0.5MPa and the pulverizing pressure is 0.7MPa, so as to obtain a fluffy negative electrode dry powder mixture; and finally, placing the dry powder mixture into a special spray gun, spraying a dry powder coating with the thickness of 1.0mm on the moving coating current collector by adopting a spraying method, and then tightly compounding the dry powder coating and the coating current collector by adopting a heating roller hot-pressing mode, wherein the hot-pressing temperature is 230 ℃, the hot-pressing pressure is 30MPa, and the hot-pressing speed is 1.2m/min, so as to obtain the single-sided negative electrode plate. And then, the same method is used for compounding a dry powder coating on the other surface of the coating current collector, and finally the double-sided composite negative plate is obtained.
Example 5
The embodiment provides a dry method for preparing a lithium ion battery electrode slice, which comprises the following steps:
preparing a positive electrode plate:
placing 100g of polyvinylidene fluoride and 50g of conductive carbon black Super P in a high-speed mixer for primary mixing, and fully mixing for 15min at a mixing speed of 200r/min; then crushing by using an air flow crusher to obtain crushed materials, wherein the air inlet pressure is 0.3MPa, and the crushing pressure is 0.5MPa; then the crushed material was mixed with 850g of LiMn 2 O 4 Placing the mixture into a double-motion mixer for mixing and stirring, wherein the mixing time is 30min, the rotating speed of a charging basket is 100r/min, the rotating speed of a blade is 50r/min, and the mixing temperature is 80 ℃ to obtain a final dry powder mixture in a fluffy state; and finally, placing the dry powder mixture into a special spray gun, spraying a dry powder coating with the thickness of 0.8mm on the moving coating current collector by adopting a spraying method, and then tightly compounding the dry powder coating and the coating current collector by adopting a heating roller hot-pressing mode, wherein the hot-pressing temperature is 250 ℃, the hot-pressing pressure is 30MPa, and the hot-pressing speed is 1.2m/min, so as to obtain the single-sided positive electrode plate. And then, the same method is used for compounding a dry powder coating on the other surface of the coating current collector, and finally the double-sided composite positive plate is obtained.
Preparing a negative electrode plate:
putting 850g of resin carbon, 100g of polyvinylidene fluoride and 50g of conductive carbon black Super P into a double-motion mixer for primary mixing, fully mixing for 30min, wherein the rotation speed of a charging basket is 20r/min, the rotation speed of a blade is 50r/min, and the mixing temperature is 65 ℃; then using an air flow pulverizer to pulverize, wherein the air inlet pressure is 0.3MPa, and the pulverizing pressure is 0.5MPa, so as to obtain a fluffy negative electrode dry powder mixture; and finally, placing the dry powder mixture into a special spray gun, spraying a dry powder coating with the thickness of 0.8mm on the moving coating current collector by adopting a spraying method, and then tightly compounding the dry powder coating and the coating current collector by adopting a heating roller hot-pressing mode, wherein the hot-pressing temperature is 250 ℃, the hot-pressing pressure is 30MPa, and the hot-pressing speed is 1.2m/min, so as to obtain the single-sided negative electrode plate. And then, the same method is used for compounding a dry powder coating on the other surface of the coating current collector, and finally the double-sided composite negative plate is obtained.
Example 6
The embodiment provides a dry method for preparing a lithium ion battery electrode slice, which comprises the following steps:
preparing a positive electrode plate:
placing 100g of polyvinylidene fluoride and 50g of acetylene black into a high-speed mixer for primary mixing, and fully mixing for 60min at a mixing speed of 50r/min; then crushing by using an air flow crusher to obtain crushed materials, wherein the air inlet pressure is 0.7MPa, and the crushing pressure is 0.8MPa; then the crushed material was mixed with 850g LiCoO 2 Placing the mixture into a double-motion mixer for mixing and stirring, wherein the mixing time is 90min, the rotating speed of a charging basket is 20r/min, the rotating speed of a blade is 50r/min, and the mixing temperature is 50 ℃ to obtain a final dry powder mixture in a fluffy state; and finally, placing the dry powder mixture into a special spray gun, spraying a dry powder coating with the thickness of 0.8mm on the moving coating current collector by adopting a spraying method, and then tightly compounding the dry powder coating and the coating current collector by adopting a heating roller hot-pressing mode, wherein the hot-pressing temperature is 200 ℃, the hot-pressing pressure is 30MPa, and the hot-pressing speed is 1.2m/min, so as to obtain the single-sided positive electrode plate. And then, the same method is used for compounding a dry powder coating on the other surface of the coating current collector, and finally the double-sided composite positive plate is obtained.
Preparing a negative electrode plate:
putting 850g of petroleum coke, 100g of polyvinylidene fluoride and 50g of acetylene black into a double-motion mixer for primary mixing, fully mixing for 30min, wherein the rotation speed of a charging basket is 20r/min, the rotation speed of a blade is 50r/min, and the mixing temperature is 65 ℃; then using an air flow pulverizer to pulverize, wherein the air inlet pressure is 0.7MPa, and the pulverizing pressure is 0.8MPa, so as to obtain a fluffy negative electrode dry powder mixture; and finally, placing the dry powder mixture into a special spray gun, spraying a dry powder coating with the thickness of 1.0mm on the moving coating current collector by adopting a spraying method, and then tightly compounding the dry powder coating and the coating current collector by adopting a heating roller hot-pressing mode, wherein the hot-pressing temperature is 200 ℃, the hot-pressing pressure is 30MPa, and the hot-pressing speed is 1.2m/min, so as to obtain the single-sided negative electrode plate. And then, the same method is used for compounding a dry powder coating on the other surface of the coating current collector, and finally the double-sided composite negative plate is obtained.
Example 7
The embodiment provides a dry method for preparing a lithium ion battery electrode slice, which comprises the following steps:
preparing a positive electrode plate:
placing 60g of polyvinylidene fluoride and 20g of acetylene black into a high-speed mixer for primary mixing, and fully mixing for 30min at a mixing speed of 100r/min; then crushing by using an air flow crusher to obtain crushed materials, wherein the air inlet pressure is 0.4MPa, and the crushing pressure is 0.6MPa; then the crushed material and 920g of LiNi 0.8 Co 0.15 Al 0.05 O 2 Placing the mixture into a double-motion mixer for mixing and stirring, wherein the mixing time is 60min, the rotating speed of a charging basket is 20r/min, the rotating speed of a blade is 50r/min, and the mixing temperature is 65 ℃ to obtain a final dry powder mixture in a fluffy state; and finally, placing the dry powder mixture into a spray gun, spraying a dry powder coating with the thickness of 0.8mm on the moving coating current collector by adopting a spraying method, and then tightly compounding the dry powder coating and the coating current collector by adopting a heating roller hot-pressing mode, wherein the hot-pressing temperature is 230 ℃, the hot-pressing pressure is 30MPa, and the hot-pressing speed is 1.2m/min, so as to obtain the single-sided positive electrode plate. And then, the same method is used for compounding a dry powder coating on the other surface of the coating current collector, and finally the double-sided composite positive plate is obtained.
Preparing a negative electrode plate:
taking 920g of carbon-coated nano silicon, 60g of polyvinylidene fluoride and 20g of acetylene black, placing the materials into a double-motion mixer for primary mixing, fully mixing for 30min, wherein the rotation speed of a charging basket is 20r/min, the rotation speed of a blade is 50r/min, and the mixing temperature is 65 ℃; then using an air flow pulverizer to pulverize, wherein the air inlet pressure is 0.4MPa, and the pulverizing pressure is 0.6MPa, so as to obtain a fluffy negative electrode dry powder mixture; and finally, placing the dry powder mixture into a spray gun, spraying a dry powder coating with the thickness of 1.0mm on the moving coating current collector by adopting a spraying method, and then tightly compounding the dry powder coating and the coating current collector by adopting a heating roller hot-pressing mode, wherein the hot-pressing temperature is 230 ℃, the hot-pressing pressure is 20MPa, and the hot-pressing speed is 1.2m/min, so as to obtain the single-sided negative electrode plate. And then, the same method is used for compounding a dry powder coating on the other surface of the coating current collector, and finally the double-sided composite negative plate is obtained.
Comparative example 1 (compared to example 1, the difference is one-step ambient temperature mixing)
The comparative example provides a dry method for preparing lithium ion battery electrode slices, which comprises the following steps:
preparing a positive electrode plate:
920g of LiNi is taken 0.5 Co 0.2 Mn 0.3 O 2 Placing 60g of Polytetrafluoroethylene (PTFE) and 20g of Keqin black into a double-motion mixer for primary mixing, fully mixing for 30min, wherein the rotation speed of a charging basket is 20r/min, the rotation speed of a blade is 50r/min, and the mixing temperature is 25 ℃; then using an air flow pulverizer to pulverize to obtain pulverized materials, wherein the air inlet pressure is 0.4MPa, and the pulverizing pressure is 0.6MPa, so as to obtain a fluffy negative electrode dry powder mixture; and finally, placing the dry powder mixture into a spray gun, spraying a dry powder coating with the thickness of 1.0mm on the moving coating current collector by adopting a spraying method, and then tightly compounding the dry powder coating and the coating current collector by adopting a heating roller hot-pressing mode, wherein the hot-pressing temperature is 230 ℃, the hot-pressing pressure is 30MPa, and the hot-pressing speed is 1.2m/min, so as to obtain the single-sided positive electrode plate. And then, the same method is used for compounding a dry powder coating on the other surface of the coating current collector, and finally the double-sided composite positive plate is obtained.
Preparing a negative electrode plate:
taking 920g of graphite, 60g of Polytetrafluoroethylene (PTFE) and 20g of Keqin black, placing the graphite, the PTFE and the Keqin black in a double-motion mixer for primary mixing, fully mixing for 30min, wherein the rotation speed of a charging basket is 20r/min, the rotation speed of a blade is 50r/min, and the mixing temperature is 25 ℃; then using an air flow pulverizer to pulverize, wherein the air inlet pressure is 0.4MPa, and the pulverizing pressure is 0.6MPa, so as to obtain a fluffy negative electrode dry powder mixture; and finally, placing the dry powder mixture into a spray gun, spraying a dry powder coating with the thickness of 1.0mm on the moving coating current collector by adopting a spraying method, and then tightly compounding the dry powder coating and the coating current collector by adopting a heating roller hot-pressing mode, wherein the hot-pressing temperature is 230 ℃, the hot-pressing pressure is 30MPa, and the hot-pressing speed is 1.2m/min, so as to obtain the single-sided negative electrode plate. And then, the same method is used for compounding a dry powder coating on the other surface of the coating current collector, and finally the double-sided composite negative plate is obtained.
Comparative example 2 (compared to example 1, the difference is that there is no jet milling step)
The comparative example provides a dry method for preparing lithium ion battery electrode slices, which comprises the following steps:
preparing a positive electrode plate:
placing 60g of Polytetrafluoroethylene (PTFE) and 20g of Keqin black into a high-speed mixer for primary mixing, and fully mixing for 30min at a mixing speed of 100r/min; then crushing to obtain crushed materials; then the crushed material and 920g of LiNi 0.5 Co 0.2 Mn 0.3 O 2 Placing the mixture into a double-motion mixer for mixing and stirring, wherein the mixing time is 60min, the rotating speed of a charging basket is 20r/min, the rotating speed of a blade is 50r/min, and the mixing temperature is 65 ℃ to obtain a final dry powder mixture in a fluffy state; and finally, placing the dry powder mixture into a spray gun, spraying a dry powder coating with the thickness of 0.8mm on the moving coating current collector by adopting a spraying method, and then tightly compounding the dry powder coating and the coating current collector by adopting a heating roller hot-pressing mode, wherein the hot-pressing temperature is 230 ℃, the hot-pressing pressure is 30MPa, and the hot-pressing speed is 1.2m/min, so as to obtain the single-sided positive electrode plate. And then, the same method is used for compounding a dry powder coating on the other surface of the coating current collector, and finally the double-sided composite positive plate is obtained.
Preparing a negative electrode plate:
taking 920g of graphite, 60g of Polytetrafluoroethylene (PTFE) and 20g of Keqin black, placing the graphite, the PTFE and the Keqin black in a double-motion mixer for primary mixing, fully mixing for 30min, wherein the rotation speed of a charging basket is 20r/min, the rotation speed of a blade is 50r/min, and the mixing temperature is 65 ℃; then crushing to obtain a fluffy negative electrode dry powder mixture; and finally, placing the dry powder mixture into a spray gun, spraying a dry powder coating with the thickness of 1.0mm on the moving coating current collector by adopting a spraying method, and then tightly compounding the dry powder coating and the coating current collector by adopting a heating roller hot-pressing mode, wherein the hot-pressing temperature is 230 ℃, the hot-pressing pressure is 30MPa, and the hot-pressing speed is 1.2m/min, so as to obtain the single-sided negative electrode plate. And then, the same method is used for compounding a dry powder coating on the other surface of the coating current collector, and finally the double-sided composite negative plate is obtained.
Comparative example 3 (compared to example 1, the difference is that remixing is not heating)
The comparative example provides a dry method for preparing lithium ion battery electrode slices, which comprises the following steps:
preparing a positive electrode plate:
placing 60g of Polytetrafluoroethylene (PTFE) and 20g of Keqin black into a high-speed mixer for primary mixing, and fully mixing for 30min at a mixing speed of 100r/min; then crushing by using an air flow crusher to obtain crushed materials, wherein the air inlet pressure is 0.4MPa, and the crushing pressure is 0.6MPa; then the crushed material and 920g of LiNi 0.5 Co 0.2 Mn 0.3 O 2 Mixing and stirring in a double-motion mixer for 60min at a charging basket rotating speed of 20r/min and a blade rotating speed of 50r/min to obtain a final dry powder mixture in a fluffy state; and finally, placing the dry powder mixture into a spray gun, spraying a dry powder coating with the thickness of 0.8mm on the moving coating current collector by adopting a spraying method, and then tightly compounding the dry powder coating and the coating current collector by adopting a heating roller hot-pressing mode, wherein the hot-pressing temperature is 230 ℃, the hot-pressing pressure is 30MPa, and the hot-pressing speed is 1.2m/min, so as to obtain the single-sided positive electrode plate. And then, the same method is used for compounding a dry powder coating on the other surface of the coating current collector, and finally the double-sided composite positive plate is obtained.
Preparing a negative electrode plate:
taking 920g of graphite, 60g of Polytetrafluoroethylene (PTFE) and 20g of ketjen black, placing the graphite, the PTFE and the ketjen black in a double-motion mixer for primary mixing, fully mixing for 30min, wherein the rotation speed of a charging basket is 20r/min, and the rotation speed of a blade is 50r/min; then using an air flow pulverizer to pulverize, wherein the air inlet pressure is 0.4MPa, and the pulverizing pressure is 0.6MPa, so as to obtain a fluffy negative electrode dry powder mixture; and finally, placing the dry powder mixture into a spray gun, spraying a dry powder coating with the thickness of 1.0mm on the moving coating current collector by adopting a spraying method, and then tightly compounding the dry powder coating and the coating current collector by adopting a heating roller hot-pressing mode, wherein the hot-pressing temperature is 230 ℃, the hot-pressing pressure is 30MPa, and the hot-pressing speed is 1.2m/min, so as to obtain the single-sided negative electrode plate. And then, the same method is used for compounding a dry powder coating on the other surface of the coating current collector, and finally the double-sided composite negative plate is obtained.
Comparative example 4 (compared to example 1, the difference is that no hot pressing is performed)
The comparative example provides a dry method for preparing lithium ion battery electrode slices, which comprises the following steps:
preparing a positive electrode plate:
placing 60g of Polytetrafluoroethylene (PTFE) and 20g of Keqin black into a high-speed mixer for primary mixing, and fully mixing for 30min at a mixing speed of 100r/min; then crushing by using an air flow crusher to obtain crushed materials, wherein the air inlet pressure is 0.4MPa, and the crushing pressure is 0.6MPa; then the crushed material and 920g of LiNi 0.5 Co 0.2 Mn 0.3 O 2 Placing the mixture into a double-motion mixer for mixing and stirring, wherein the mixing time is 60min, the rotating speed of a charging basket is 20r/min, the rotating speed of a blade is 50r/min, and the mixing temperature is 65 ℃ to obtain a final dry powder mixture in a fluffy state; finally, the dry powder mixture is coated on the current collector.
Preparing a negative electrode plate:
taking 920g of graphite, 60g of Polytetrafluoroethylene (PTFE) and 20g of Keqin black, placing the graphite, the PTFE and the Keqin black in a double-motion mixer for primary mixing, fully mixing for 30min, wherein the rotation speed of a charging basket is 20r/min, the rotation speed of a blade is 50r/min, and the mixing temperature is 65 ℃; then crushing the mixture by using an air flow crusher, wherein the air inlet pressure is 0.4MPa, and the crushing pressure is 0.6MPa, so as to obtain a fluffy negative electrode dry powder mixture; finally, the dry powder mixture is coated on the current collector.
Performance testing
The electrode sheets obtained in the embodiment and the comparative example of the invention are subjected to performance test, and specifically comprise: peel strength, internal resistance. The electrode plate is assembled into a button cell to test the electrical property, and the method specifically comprises the following steps: first coulombic efficiency, capacity, and cycle performance, etc. Since comparative example 4 was not subjected to hot pressing, the dry powder could not be adhered to the current collector, and thus the pole piece could not be obtained.
Test method of peel strength: the 180 ° peel strength of the electrode sheet was tested using a tensiometer.
The method for testing the internal resistance comprises the following steps: the sheet resistance of the pole piece was tested using a four-probe tester.
Test method of first coulombic efficiency, 0.1C capacity and cycle performance: assembling the pole pieces into a CR2025 button cell, and using a Xinwei cell tester to carry out charge and discharge test on the cell, wherein the voltage interval of the negative electrode is 0.005-1.5V, and the charge and discharge current is 0.5mA; the positive voltage interval is 3-4.3V, and the charge-discharge current is 1mA.
The test results are shown in the following table:
table 1-positive plate:
Figure BDA0003364444350000181
Figure BDA0003364444350000191
table 2-negative electrode sheet:
Figure BDA0003364444350000192
remarks: the resistance value is 10 multiplied by 10cm, the thickness of the positive plate is 200 mu m, and the thickness of the negative plate is 150 mu m.
From the contents of tables 1 and 2, it can be seen that: for the preparation process of the positive plate, firstly, the adhesive and the conductive agent with similar density and size particles are mixed at high speed, then the conductive agent and the adhesive are crushed by using an air flow crushing mode to obtain full crushed materials, and the air flow crushing process can refine and homogenize the sizes of the conductive agent and the adhesive and can also fiberize the adhesive, so that the conductivity and the cohesiveness of the plate are further improved; then the crushed materials of the conductive agent and the binder are continuously mixed with the active material, and as the active material particles and the density are large, the powder can be more uniformly mixed by adopting a double-motion mixing mode; meanwhile, the powder is heated in the mixing process, so that the preactivation process is realized, and the powder is more stable in the spraying process. For the preparation process of the negative plate, the particle size and density of the negative active material, the conductive agent and the binder are not greatly different, so that the mixing process of the negative material can be further simplified, and the final dry powder is obtained by carrying out double-motion mixing and then carrying out jet milling.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. And obvious variations or modifications thereof are contemplated as falling within the scope of the present invention.

Claims (10)

1. The dry preparation method of the lithium ion battery electrode slice is characterized by comprising the following steps of:
primary mixing: mixing the conductive agent and the binder, and carrying out jet milling under the pressure of 0.5-0.8MPa to obtain a ground material;
remixing: mixing the obtained crushed material with active substances at 50-80 ℃ to obtain a mixture;
coating: and spraying the obtained mixture onto a current collector, hot-pressing to obtain a single-sided dry electrode, and spraying and hot-pressing the other side of the current collector again to obtain the double-sided composite pole piece.
2. The dry preparation method of the lithium ion battery electrode slice according to claim 1, wherein in the primary mixing step, the mixing time is 15-60min, and the mixing rotating speed is 50-200r/min;
in the remixing step, the mixing time is 30-90min, and the mixing rotating speed is 20-100r/min.
3. The dry method for preparing the electrode slice of the lithium ion battery according to claim 1, wherein the hot pressing temperature is 200-250 ℃, the pressure is 15-40Mpa, and the speed is 0.5-2m/min.
4. The dry preparation method of the lithium ion battery electrode slice according to claim 1, wherein the mass ratio of the active substance, the conductive agent and the binder is (85-95): (1-5): (4-10).
5. The method for dry production of a lithium ion battery electrode sheet according to claim 1, wherein the active material is a positive electrode active material or a negative electrode active material.
6. The dry method for preparing an electrode sheet for a lithium ion battery according to claim 5, wherein when the active material is a negative electrode active material, the step of mixing and remixing is: mixing active material, conductive agent and binder at 50-80deg.C, and jet pulverizing under 0.5-0.8MPa to obtain mixture.
7. The method according to claim 6, wherein when the active material is a negative electrode active material, the mixing time is 30-90min and the mixing speed is 20-100r/min.
8. The dry method preparation method of the lithium ion battery electrode slice according to claim 1, wherein the single-sided spraying thickness of the mixture is 0.5-2mm.
9. The dry method for preparing an electrode sheet of a lithium ion battery according to claim 5, wherein the conductive agent is at least one of ketjen black, conductive carbon black Super P and acetylene black;
the binder is polytetrafluoroethylene and/or polyvinylidene fluoride;
the positive electrode active material is LiMn 2 O 4 ，LiCoO 2 ，LiFePO 4 ，LiNi x Co y Mn z O 2 (x+y+z＝1，0<x<1，0<y<1，0<z<1)、LiNi x Co y Al z O 2 (x+y+z＝1，0<x<1，0<y<1，0<z<1) At least one of the compounds;
the negative electrode active material is at least one of graphite, hard carbon material, soft carbon material and silicon-carbon composite material.
10. A lithium ion battery electrode sheet prepared by the method of any one of claims 1-9.
CN202111399152.XA 2021-11-19 2021-11-19 Lithium ion battery electrode slice and dry preparation method thereof Pending CN116154110A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116706074A (en) * 2023-08-02 2023-09-05 中创新航科技集团股份有限公司 Dry electrode preparation method, battery and dry electrode preparation device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116706074A (en) * 2023-08-02 2023-09-05 中创新航科技集团股份有限公司 Dry electrode preparation method, battery and dry electrode preparation device
CN116706074B (en) * 2023-08-02 2023-10-20 中创新航科技集团股份有限公司 Dry electrode preparation method, battery and dry electrode preparation device

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