CN114899412A - Electrode structure, preparation method thereof, negative plate and secondary battery - Google Patents

Electrode structure, preparation method thereof, negative plate and secondary battery Download PDF

Info

Publication number
CN114899412A
CN114899412A CN202210514728.0A CN202210514728A CN114899412A CN 114899412 A CN114899412 A CN 114899412A CN 202210514728 A CN202210514728 A CN 202210514728A CN 114899412 A CN114899412 A CN 114899412A
Authority
CN
China
Prior art keywords
electrode structure
active material
current collector
mixing
minutes
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202210514728.0A
Other languages
Chinese (zh)
Inventor
陈黄
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hunan Lifang New Energy Science and Technology Co Ltd
Original Assignee
Hunan Lifang New Energy Science and Technology Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hunan Lifang New Energy Science and Technology Co Ltd filed Critical Hunan Lifang New Energy Science and Technology Co Ltd
Priority to CN202210514728.0A priority Critical patent/CN114899412A/en
Publication of CN114899412A publication Critical patent/CN114899412A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • 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
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/665—Composites
    • H01M4/667—Composites in the form of layers, e.g. coatings
    • 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
    • H01M10/054—Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • 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
    • H01M4/04—Processes of manufacture in general
    • H01M4/0402—Methods of deposition of the material
    • H01M4/0404—Methods of deposition of the material by coating on electrode collectors
    • 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
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H01M4/136—Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • 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
    • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • 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
    • H01M4/1397—Processes of manufacture of electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy
    • 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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/027—Negative electrodes
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Inorganic Chemistry (AREA)
  • Composite Materials (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

The invention belongs to the technical field of secondary batteries, and particularly relates to an electrode structure, a preparation method of the electrode structure, a negative plate and a secondary battery. The electrode structure provided by the invention can avoid the defects of micropores, cracks and the like generated by the current collector under rolling, and improves the quality and performance of the pole piece.

Description

Electrode structure, preparation method thereof, negative plate and secondary battery
Technical Field
The invention belongs to the technical field of secondary batteries, and particularly relates to an electrode structure, a preparation method of the electrode structure, a negative plate and a secondary battery.
Background
With the rapid development of battery technology, the requirements of batteries are higher, and especially the energy density and safety of batteries are important. In order to pursue a battery with high energy density, an active material with high energy density is usually selected, and in order to make the energy density of the active material exert the most effectively, the electrode pole pieces of the positive and negative electrodes are designed to have high compaction density, and the required energy density of the battery is exerted by the designed compaction density of rolling. Taking the electrode structure of a lithium battery as an example, the electrode structure generally comprises a positive electrode, a negative electrode, a diaphragm and electrolyte, wherein a base material required by the positive electrode is aluminum foil, a base material required by the negative electrode is copper foil, and the positive electrode and the negative electrode generally coat an active material layer on the surface of the required base material to prepare a required electrode layer. In order to effectively exert the energy density of the active material, a roll-in process is generally adopted, and the purpose is to increase the compaction density of the anode or cathode material, and the proper compaction density can increase the discharge capacity of the battery, reduce the internal resistance, reduce the polarization loss, prolong the cycle life of the battery and improve the utilization rate of the lithium ion battery. However, the active material has a certain hardness, and has a certain physical damage to the base material, such as generation of defects of micropores, cracks and the like on the surface of the base material, thereby affecting the electrical performance, safety performance and the like of the battery. Therefore, it is necessary to provide an electrode structure.
Disclosure of Invention
One of the objects of the present invention is: aiming at the defects of the prior art, the electrode structure is provided, the defects of micropores, cracks and the like generated by a current collector under rolling can be avoided, and the quality and the performance of a pole piece are improved.
In order to achieve the purpose, the invention adopts the following technical scheme:
an electrode structure comprises a current collector, a protective layer arranged on the surface of the current collector and an active substance layer arranged on one side, far away from the current collector, of the protective layer.
Preferably, the thickness of the protective layer is 1.0-10.0 μm.
Preferably, the thickness of the current collector is 4.5-20 μm, and the thickness of the active material layer is 15-150 μm.
A method of making an electrode structure comprising the steps of:
step S1, mixing and stirring the high molecular polymer and the organic solvent, performing vacuum treatment to obtain a first glue solution, coating the first glue solution on the surfaces of the two sides of the current collector, and drying to form a protective layer to obtain a treated sheet;
and step S2, carrying out first mixing on the binder and the solvent to obtain a second glue solution, carrying out second mixing on the active material and the second glue solution, adding the thickening agent to carry out third mixing, carrying out vacuum treatment to obtain active material slurry, coating the active material slurry on the surface of the protective layer, and drying to form an active material layer to obtain the electrode structure.
Preferably, the weight part ratio of the high molecular polymer to the organic solvent in the step S1 is 2-10: 90-98.
Preferably, the stirring time in the step S1 is 2-5 hours, the vacuum degree of the vacuum treatment is-80 KPa to-100 KPa, and the vacuum treatment time is 20-50 minutes.
Preferably, the weight part ratio of the active substance, the thickening agent and the binder in the step S2 is 90-98: 0.1-5: 0.5-5.
Preferably, the first mixing time in the step S2 is 30 to 60 minutes, the second mixing time is 100 to 150 minutes, the third mixing time is 30 to 60 minutes, the vacuum treatment time is 30 to 60 minutes, and the vacuum degree of the vacuum treatment is-80 KPa to-100 KPa.
The second purpose of the invention is: aiming at the defects of the prior art, the preparation method of the electrode structure is provided, and has the advantages of simple operation, good controllability and batch production.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method of making an electrode structure comprising the steps of:
step S1, mixing and stirring the high molecular polymer and the organic solvent, performing vacuum treatment to obtain a first glue solution, coating the first glue solution on the surfaces of the two sides of the current collector, and drying to form a protective layer to obtain a treated sheet;
and step S2, carrying out first mixing on the binder and the solvent to obtain a second glue solution, carrying out second mixing on the active material and the second glue solution, adding the thickening agent to carry out third mixing, carrying out vacuum treatment to obtain active material slurry, coating the active material slurry on the surface of the protective layer, and drying to form an active material layer to obtain the electrode structure.
The third purpose of the invention is that: aiming at the defects of the prior art, the negative plate is provided, and has good quality and electrochemical performance.
In order to achieve the purpose, the invention adopts the following technical scheme:
a negative plate comprises the electrode structure.
The fourth purpose of the invention is that: in view of the shortcomings of the prior art, a secondary battery with good quality and electrochemical performance is provided.
In order to achieve the purpose, the invention adopts the following technical scheme:
a secondary battery comprises the negative plate.
Compared with the prior art, the invention has the beneficial effects that: according to the electrode structure, the protective layer is arranged between the current collector and the active substance layer, so that the active substance layer can be prevented from being in direct contact with the current collector, the current collector is prevented from being damaged due to overlarge stress, the current collector is prevented from having the defects of micropores, cracks and the like, the quality and the safety performance of the electrode are improved, and the quality and the performance of the battery are further improved.
Drawings
Fig. 1 is a schematic structural view of an electrode structure of the present invention.
Fig. 2 is a schematic view of the electrode structure of the present invention when subjected to roll pressing.
Wherein: 1. a current collector; 2. a protective layer; 3. an active material layer; 4. and (4) rolling.
Detailed Description
1. An electrode structure can avoid the defects of micropores, cracks and the like generated by a current collector 1 under rolling and improve the quality and the performance of a pole piece.
An electrode structure comprises a current collector 1, a protective layer 2 arranged on the surface of the current collector 1 and an active substance layer 3 arranged on one side, far away from the current collector 1, of the protective layer 2.
Traditional electrode is because there is not protective layer 2, and active material direct coating obtains active substance layer 3 on the mass flow body 1 surface after the stoving roll-in, causes the damage to the mass flow body 1 easily at the roll-in-process, leads to the defects such as micropore, crackle appear on the mass flow body 1 surface to lead to the mechanical properties of the mass flow body 1 to descend, and performance such as hardness, toughness are not good, and then influence the quality and the performance of pole piece and secondary battery. According to the electrode structure, the protective layer 2 is arranged between the current collector 1 and the active substance layer 3, so that the active substance layer 3 can be prevented from being in direct contact with the current collector 1, the current collector 1 is prevented from being damaged due to overlarge stress, the current collector 1 is prevented from having the defects of micropores, cracks and the like, the quality and the safety performance of an electrode are improved, and the quality and the performance of a battery are further improved.
Preferably, the thickness of the protective layer 2 is 1.0 to 10.0 μm. The protective layer 2 is too thin to protect the current collector 1, and the protective layer 2 is too thick to affect the desorption of the active material from the active material layer 3.
Preferably, the thickness of the current collector 1 is 4.5 to 20 μm, and the thickness of the active material layer 3 is 15 to 150 μm. The thickness that sets up mass flow body 1, protective layer 2 and active material layer 3 is in certain proportion, makes the performance of pole piece better, has both certain mechanical properties, also has certain active material and provides the energy.
2. The preparation method of the electrode structure is simple to operate, good in controllability and capable of realizing batch production.
A method of making an electrode structure comprising the steps of:
step S1, mixing and stirring the high molecular polymer and the organic solvent, performing vacuum treatment to obtain a first glue solution, coating the first glue solution on the surfaces of the two sides of the current collector 1, and drying to form a protective layer 2 to obtain a treated sheet;
and step S2, carrying out first mixing on the binder and the solvent to obtain a second glue solution, carrying out second mixing on the active material and the second glue solution, adding the thickening agent to carry out third mixing, carrying out vacuum treatment to obtain active material slurry, coating the active material slurry on the surface of the protective layer 2, and drying to form the active material layer 3 to obtain the electrode structure.
According to the preparation method of the electrode structure, the first glue solution is prepared firstly, the first glue solution is coated on the surface of the current collector 1 to obtain the treated sheet, the current collector 1 with the protective layers 2 on the two side surfaces is obtained, the active substance slurry is coated on the surface of the protective layer 2, and the electrode structure is obtained through drying.
Wherein, the high molecular polymer can be one or more than two of polyamide imide, polyvinylidene fluoride, polyvinyl alcohol, polytetrafluoroethylene, polyolefin and polyurethane. Preferably, the high molecular polymer is polyamide imide, contains amido bond (-N-H), and can realize a self-repairing function through the action of multiple hydrogen bonds, so that the service life of the high molecular polymer can be effectively prolonged. Wherein the drying temperature in the step S1 and the step S2 is 90-98 ℃, and the drying time is 1-10 min. Preferably, the temperature for drying in steps S1 and S2 is 95 ℃ and the drying time is 5 min.
Preferably, the weight part ratio of the high molecular polymer to the organic solvent in the step S1 is 2-10: 90-98. The weight ratio of the high molecular polymer to the organic solvent is 5-10: 90-98, 6-10: 92-98 and 6-8: 95-98, and preferably, the weight ratio of the high molecular polymer to the organic solvent is 5:92, 6:93, 7:94, 8:96, 10:97 and 10: 98.
Preferably, the stirring time in the step S1 is 2-5 hours, the vacuum degree of the vacuum treatment is-80 KPa to-100 KPa, and the vacuum treatment time is 20-50 minutes. Preferably, the stirring time is 2 hours, 3 hours, 4 hours and 5 hours, the vacuum degree of the vacuum treatment is-80 KPa, -85KPa, -90KPa and-100 KPa, and the vacuum treatment time is 20 minutes, 30 minutes, 40 minutes and 50 minutes.
Preferably, the weight part ratio of the active substance, the thickener and the binder in the step S2 is 90-98: 0.1-5: 0.5-5. The weight part ratio of the active substance, the thickening agent and the binder in the step S2 is 92-98: 0.1-2: 0.5-3, 94-98: 0.5-2: 0.5-3, 93-98: 0.6-2: 1-3 and 92-97: 0.6-2: 1-3, and preferably, the weight part ratio of the active substance, the thickening agent and the binder in the step S2 is 92:1.5:2, 92:1.5:3, 94:1:2, 97:0.5:1.5, 94:1.5:2, 96:1.4:2, 94:1.5:3 and 96:1.4: 2.
Preferably, the first mixing time in the step S2 is 30 to 60 minutes, the second mixing time is 100 to 150 minutes, the third mixing time is 30 to 60 minutes, the vacuum treatment time is 30 to 60 minutes, and the vacuum degree of the vacuum treatment is-80 KPa to-100 KPa. Preferably, the time of the first mixing is 30 minutes, 40 minutes, 50 minutes, 60 minutes, the time of the second mixing is 100 minutes, 110 minutes, 120 minutes, 130 minutes, 140 minutes, 150 minutes, the time of the third mixing is 30 minutes, 40 minutes, 50 minutes, 60 minutes, and the degree of vacuum of the vacuum treatment is-80 KPa, -90KPa, -100 KPa.
3. A negative electrode sheet having good quality and electrochemical properties.
A negative plate comprises the electrode structure.
4. A secondary battery having good quality and electrochemical properties.
A secondary battery comprises the negative plate. Specifically, a secondary battery may be a lithium ion battery, a sodium ion battery, a magnesium ion battery, a calcium ion battery, a potassium ion battery, or the like. The following secondary battery is exemplified by a lithium ion battery, which comprises a positive plate, a negative plate, a diaphragm, electrolyte and a shell, wherein the positive plate and the negative plate are separated by the diaphragm, and the shell is used for installing the positive plate, the negative plate, the diaphragm and the electrolyte. The negative plate is prepared as above.
Positive electrode
The positive plate comprises a positive current collector 1 and a positive active material layer 3 arranged on at least one surface of the positive current collector 1, wherein the positive active material layer 3 comprises a positive active material, and the positive active material can be a chemical formula including but not limited to Li a Ni x Co y M z O 2-b N b (wherein a is more than or equal to 0.95 and less than or equal to 1.2, x>0, y is more than or equal to 0, z is more than or equal to 0, and x + y + z is 1,0 is more than or equal to b and less than or equal to 1, M is selected from one or more of Mn and Al and N is selected from F, P, S), and the positive active material can also be selected from the group consisting of but not limited to LiCoO 2 、LiNiO 2 、LiVO 2 、LiCrO 2 、LiMn 2 O 4 、LiCoMnO 4 、Li 2 NiMn 3 O 8 、LiNi 0.5 Mn 1.5 O 4 、LiCoPO 4 、LiMnPO 4 、LiFePO 4 、LiNiPO 4 、LiCoFSO 4 、CuS 2 、FeS 2 、MoS 2 、NiS、TiS 2 And the like. The positive electrode active material may be further modified, and the method of modifying the positive electrode active material is known to those skilled in the art, for example, the positive electrode active material may be modified by coating, doping, and the like, and the material used in the modification may be one or a combination of more of Al, B, P, Zr, Si, Ti, Ge, Sn, Mg, Ce, W, and the like. While the positive electrode current collector 1 is generally a structure or a part for collecting current, the positive electrode current collector 1 may be any material suitable for use as a positive electrode current collector 1 of a lithium ion battery in the art, for example, the positive electrode current collector 1 may include, but is not limited to, a metal foil, and the like, and more specifically, may include, but is not limited to, an aluminum foil, and the like.
Electrolyte solution
The lithium ion battery also comprises electrolyte, and the electrolyte comprises an organic solvent, electrolyte lithium salt and an additive. Wherein the electrolyte lithium salt may be LiPF used in a high-temperature electrolyte 6 And/or LiBOB; or LiBF used in low-temperature electrolyte 4 、LiBOB、LiPF 6 At least one of; or LiBF used in anti-overcharge electrolyte 4 、LiBOB、LiPF 6 At least one of LiTFSI; may also be LiClO 4 、LiAsF 6 、LiCF 3 SO 3 、LiN(CF 3 SO 2 ) 2 At least one of (1). And the organic solvent may be a cyclic carbonate including PC, EC; or chain carbonates including DFC, DMC, or EMC; and also carboxylic acid esters including MF, MA, EA, MP, etc. And additives include, but are not limited to, film forming additives, conductive additives, flame retardant additives, anti-overcharge additives, control additives in electrolytesH 2 At least one of additives of O and HF content, additives for improving low temperature performance, and multifunctional additives.
Preferably, the material of the shell is one of stainless steel and an aluminum plastic film. More preferably, the housing is an aluminum plastic film.
The present invention will be described in further detail with reference to the following detailed description and the accompanying drawings, but the embodiments of the invention are not limited thereto.
Example 1
1. A method of making an electrode structure comprising the steps of:
step S1, mixing and stirring the high molecular polymer and the organic solvent, performing vacuum treatment to obtain a first glue solution, coating the first glue solution on the surfaces of the two sides of the current collector 1, and drying to form a protective layer 2 to obtain a treated sheet;
step S2, carrying out first mixing on the binder and the solvent to obtain a second glue solution, carrying out second mixing on the active substance and the second glue solution, adding the thickening agent to carry out third mixing, carrying out vacuum treatment to obtain active substance slurry, coating the active substance slurry on one surface of the protective layer 2, rolling the active substance slurry by a roller 4, drying the active substance slurry to form an active substance layer 3 as shown in figure 2, coating the active substance slurry on the other surface of the protective layer 2, rolling the active substance slurry by a roller 4, and drying the active substance layer 3 to obtain the electrode structure as shown in figure 1.
Wherein the weight part ratio of the high molecular polymer to the organic solvent in the step S1 is 7: 93. The high molecular polymer is polyamide imide, and the organic solvent is N-methyl pyrrolidone.
Wherein the stirring time in the step S1 is 3 hours, the vacuum degree of the vacuum treatment is 90Kpa, and the vacuum treatment time is 30 minutes.
In the step S2, the weight part ratio of the active substance, the thickening agent and the binder is 97:1:2, the active substance is graphite, the thickening agent is carboxymethyl cellulose, and the binder is polystyrene butadiene copolymer.
Wherein the first mixing time is 50 minutes, the second mixing time is 120 minutes, the third mixing time is 45 minutes, the vacuum processing time is 45 minutes, and the vacuum degree of the vacuum processing is 90Kpa in the step S2.
In the electrode structure obtained above, the thickness of the protective layer 2 was 8 μm, the thickness of the current collector 1 was 6 μm, and the thickness of the active material layer 3 was 20 μm.
2. Preparing a negative plate: and (3) cutting edges, cutting pieces and dividing the electrode structure into strips, drying the strips for 4 hours at 110 ℃ under a vacuum condition, and welding lugs to prepare the lithium ion battery cathode piece.
3. Preparing a positive plate: lithium cobaltate, conductive agent superconducting carbon (Super-P) and binder polyvinylidene fluoride (PVDF) are mixed according to the mass ratio of 97: 1.5: 1.5, uniformly mixing to prepare lithium ion battery anode slurry with certain viscosity, coating the slurry on a current collector 1 aluminum foil, drying at 85 ℃, and then carrying out cold pressing; then trimming, cutting into pieces, slitting, drying for 4 hours at 110 ℃ under the vacuum condition after slitting, and welding the tabs to prepare the lithium ion battery positive plate.
4. Preparing an electrolyte: mixing lithium hexafluorophosphate (LiPF) 6 ) The electrolyte was dissolved in a mixed solvent composed of Ethylene Carbonate (EC), dimethyl carbonate (DMC) and Ethyl Methyl Carbonate (EMC) (mass ratio of 1:2:1) to obtain an electrolyte solution having a concentration of 1 mol/L.
5. The isolating membrane is a 6 mu m polypropylene isolating membrane.
6. Preparing a lithium ion battery: winding the positive plate, the diaphragm and the prepared negative plate into a battery cell, wherein the polypropylene isolating film is positioned between the positive plate and the negative plate, the positive electrode is led out by aluminum tab spot welding, and the negative electrode is led out by nickel tab spot welding; and then placing the battery core in an aluminum-plastic packaging bag, injecting the electrolyte, and carrying out processes such as packaging, formation, capacity and the like to prepare the lithium ion battery.
Example 2
The difference from example 1 is that: the weight part ratio of the high molecular polymer to the organic solvent in the step S1 is 5: 95.
The rest is the same as embodiment 1, and the description is omitted here.
Example 3
The difference from example 1 is that: the weight part ratio of the high molecular polymer to the organic solvent in the step S1 is 2: 98.
The rest is the same as embodiment 1, and the description is omitted here.
Example 4
The difference from example 1 is that: the weight part ratio of the high molecular polymer to the organic solvent in the step S1 is 9: 91.
The rest is the same as embodiment 1, and the description is omitted here.
Example 5
The difference from example 1 is that: the weight part ratio of the high molecular polymer to the organic solvent in the step S1 is 10: 90.
The rest is the same as embodiment 1, and the description is omitted here.
Example 6
The difference from example 1 is that: in the step S2, the weight part ratio of the active substance to the thickening agent to the binder is 98:1: 1.
The rest is the same as embodiment 1, and the description is omitted here.
Example 7
The difference from example 1 is that: in the step S2, the weight part ratio of the active substance to the thickening agent to the binder is 95:2: 3.
The rest is the same as embodiment 1, and the description is omitted here.
Example 8
The difference from example 1 is that: in the step S2, the weight part ratio of the active substance to the thickening agent to the binder is 92:4: 4.
The rest is the same as embodiment 1, and the description is omitted here.
Example 9
The difference from example 1 is that: in the step S2, the weight part ratio of the active substance to the thickening agent to the binder is 93:2: 5.
The rest is the same as embodiment 1, and the description is omitted here.
Example 10
The difference from example 1 is that: in the step S2, the weight part ratio of the active substance to the thickening agent to the binder is 97.5:0.5: 2.
The rest is the same as embodiment 1, and the description is omitted here.
Example 11
The difference from example 1 is that: the thickness of the protective layer 2 was 10.0 μm.
The rest is the same as embodiment 1, and the description is omitted here.
Example 12
The difference from example 1 is that: the thickness of the protective layer 2 was 9.0 μm.
The rest is the same as embodiment 1, and the description is omitted here.
Example 13
The difference from example 1 is that: the thickness of the protective layer 2 was 5.0 μm.
The rest is the same as embodiment 1, and the description is omitted here.
Example 14
The difference from example 1 is that: the thickness of the protective layer 2 was 2.0 μm.
The rest is the same as embodiment 1, and the description is omitted here.
And (3) performance testing: the electrode structures, negative electrode sheets and secondary batteries prepared in the above examples 1 to 10 and comparative example 1 were compared in performance, and the test results are reported in table 1.
1. The lithium ion battery cycle life testing method comprises the following steps:
charging and discharging the lithium ion battery at 45 ℃, namely charging the lithium ion battery to 4.2V by using a current of 1C, then discharging the lithium ion battery to 2.8V by using a current of 1C, and recording the discharge capacity of the first week; then, the battery was subjected to 1C/1C charge-discharge cycle for 1000 weeks, the discharge capacity of the battery at the 1000 th week was recorded, and the discharge capacity at the 1000 th week was divided by the discharge capacity at the first week to obtain the capacity retention rate at the 1000 th week.
2. The DCR growth rate test method comprises the following steps:
the secondary battery was adjusted to 50% SOC at 25 ℃ with 1C current, and voltage U1 was recorded. Then discharged at 4C for 30 seconds and voltage U2 recorded. DCR ═ (U1-U2)/4C. The cell was then subjected to a 1C/1C charge-discharge cycle for 500 weeks, the DCR at week 500 was recorded, and the DCR at week 500 was divided by the DCR at week 500 and subtracted by 1 to obtain the DCR increase rate at week 500.
3. And (3) needle punching test: the secondary batteries (10 samples) were fully charged at a current of 1C to a charge cut-off voltage, and then charged at a constant voltage until the current was reduced to 0.05C, and the charging was stopped. And (3) penetrating the battery plate from the direction vertical to the battery plate at the speed of 25mm/s by using a high-temperature-resistant steel needle with the diameter of 8mm, wherein the penetrating position is close to the geometric center of the punctured surface, and the steel needle stays in the battery to observe whether the battery has combustion and explosion phenomena.
4. A flexibility tester is used according to a national standard test method, and the diameters of the shaft rods used in the experiment are respectively 15mm, 10mm, 5mm, 4mm, 1.5mm, 1mm and 0.5 mm; the pole piece to be measured is bent on a mandrel with the diameter from large to small, the state of the pole piece in a bending area is observed by using an optical microscope, when the pole piece is cracked for the first time, the diameter of the last mandrel is recorded as a corresponding flexibility value, and the flexibility value is recorded in a table 1.
TABLE 1
Figure BDA0003641004820000111
It can be seen from the comparison of examples 1-14 with comparative example 1 that when the electrode structure and the secondary battery according to the present invention are prepared, the secondary battery has better flexibility, mechanical strength and electrochemical properties. As shown by comparison of examples 1 to 5, when the weight ratio of the high molecular polymer to the organic solvent in step S1 is 7:93, the performance of the prepared secondary battery is better, and the slurry prepared from the high molecular polymer with appropriate viscosity and concentration is more firmly combined with the current collector 1, so that the current collector 1 is better protected, and the battery performance is improved. From comparison of examples 1 and 6 to 10, it is found that when the weight part ratio of the active material, the thickener and the binder in step S2 is set to 98:1:1, the prepared secondary battery has better performance, and the proper ratio is set, so that the active material slurry is bonded more firmly, and the prepared secondary battery has better performance. When the amount of the binder or thickener used is increased, the active material is easily deintercalated. As shown by comparison of examples 1 and 11 to 14, when the thickness of the protective layer 2 is set to be 8 μm, the performance of the prepared secondary battery is better, and when the thickness of the protective layer 2 is too small, the protective property of the current collector 1 is poor, the mechanical strength is easy to decrease, and cracks and other damages are easy to occur; when the thickness of the protective layer 2 is excessively large, the desorption of the active material is easily affected, thereby affecting the performance of the secondary battery.
Variations and modifications to the above-described embodiments may also occur to those skilled in the art, which fall within the scope of the invention as disclosed and taught herein. Therefore, the present invention is not limited to the above-mentioned embodiments, and any obvious improvement, replacement or modification made by those skilled in the art based on the present invention is within the protection scope of the present invention. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

Claims (10)

1. The electrode structure is characterized by comprising a current collector, a protective layer arranged on the surface of the current collector and an active substance layer arranged on one side, far away from the current collector, of the protective layer.
2. The electrode structure of claim 1, wherein the protective layer has a thickness of 1.0-10.0 μm.
3. The electrode structure according to claim 1 or 2, wherein the current collector has a thickness of 4.5 to 20 μm, and the active material layer has a thickness of 15 to 150 μm.
4. A method of manufacturing an electrode structure according to any one of claims 1 to 3, comprising the steps of:
step S1, mixing and stirring the high molecular polymer and the organic solvent, performing vacuum treatment to obtain a first glue solution, coating the first glue solution on the surfaces of the two sides of the current collector, and drying to form a protective layer to obtain a treated sheet;
and step S2, carrying out first mixing on the binder and the solvent to obtain a second glue solution, carrying out second mixing on the active material and the second glue solution, adding the thickening agent to carry out third mixing, carrying out vacuum treatment to obtain active material slurry, coating the active material slurry on the surface of the protective layer, and drying to form an active material layer to obtain the electrode structure.
5. The method according to claim 4, wherein the weight ratio of the polymer to the organic solvent in step S1 is 2-10: 90-98.
6. The method for manufacturing an electrode structure according to claim 4 or 5, wherein in the step S1, the stirring time is 2 to 5 hours, the vacuum degree of the vacuum treatment is-80 KPa to-100 KPa, and the vacuum treatment time is 20 to 50 minutes.
7. The method of claim 4, wherein the weight ratio of the active material, the thickener and the binder in step S2 is 90-98: 0.1-5: 0.5-5.
8. The method for manufacturing an electrode structure according to claim 4 or 7, wherein the time for the first mixing in step S2 is 30 to 60 minutes, the time for the second mixing is 100 to 150 minutes, the time for the third mixing is 30 to 60 minutes, the time for the vacuum treatment is 30 to 60 minutes, and the degree of vacuum of the vacuum treatment is-80 KPa to-100 KPa.
9. A negative electrode sheet, comprising the electrode structure of any one of claims 1 to 3.
10. A secondary battery comprising the electrode structure of claim 9.
CN202210514728.0A 2022-05-12 2022-05-12 Electrode structure, preparation method thereof, negative plate and secondary battery Pending CN114899412A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210514728.0A CN114899412A (en) 2022-05-12 2022-05-12 Electrode structure, preparation method thereof, negative plate and secondary battery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210514728.0A CN114899412A (en) 2022-05-12 2022-05-12 Electrode structure, preparation method thereof, negative plate and secondary battery

Publications (1)

Publication Number Publication Date
CN114899412A true CN114899412A (en) 2022-08-12

Family

ID=82721394

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210514728.0A Pending CN114899412A (en) 2022-05-12 2022-05-12 Electrode structure, preparation method thereof, negative plate and secondary battery

Country Status (1)

Country Link
CN (1) CN114899412A (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013201062A (en) * 2012-03-26 2013-10-03 Toppan Printing Co Ltd Manufacturing method of all-solid lithium ion secondary battery
US20140242458A1 (en) * 2013-02-25 2014-08-28 Kabushiki Kaisha Toyota Jidoshokki Negative electrode for nonaqueous secondary battery, method for producing the same, and nonaqueous secondary battery
CN208298924U (en) * 2018-04-27 2018-12-28 宁德新能源科技有限公司 Pole piece and electrochemical appliance
CN110556511A (en) * 2019-09-03 2019-12-10 珠海格力电器股份有限公司 Lithium battery negative pole piece with excellent cycle performance, preparation method thereof and lithium ion battery
CN114284507A (en) * 2020-09-27 2022-04-05 北京卫国创芯科技有限公司 Negative electrode sandwich structure, preparation method and application thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013201062A (en) * 2012-03-26 2013-10-03 Toppan Printing Co Ltd Manufacturing method of all-solid lithium ion secondary battery
US20140242458A1 (en) * 2013-02-25 2014-08-28 Kabushiki Kaisha Toyota Jidoshokki Negative electrode for nonaqueous secondary battery, method for producing the same, and nonaqueous secondary battery
CN208298924U (en) * 2018-04-27 2018-12-28 宁德新能源科技有限公司 Pole piece and electrochemical appliance
CN110556511A (en) * 2019-09-03 2019-12-10 珠海格力电器股份有限公司 Lithium battery negative pole piece with excellent cycle performance, preparation method thereof and lithium ion battery
CN114284507A (en) * 2020-09-27 2022-04-05 北京卫国创芯科技有限公司 Negative electrode sandwich structure, preparation method and application thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
李晓华: "《基础化学实训指导手册》", 31 January 2022, 武汉理工大学出版社, pages: 105 *

Similar Documents

Publication Publication Date Title
US11355742B2 (en) Negative electrode plate and lithium-ion secondary battery
US11196041B2 (en) Positive electrode plate and lithium-ion secondary battery
CN111916706B (en) Lithium ion secondary battery, method for manufacturing same, and electric vehicle, consumer electronic product, and mechanical device including same
CN101699590B (en) Hybrid supercapacitor
CN106711430A (en) Production method of lithium/carbon fiber or porous carbon paper/copper foil composite negative electrode used for lithium-sulfur battery
JP7106746B2 (en) lithium ion secondary battery
JP7106762B2 (en) Positive electrode sheet, manufacturing method thereof, and lithium ion secondary battery
CN110265622B (en) Positive electrode plate and lithium ion secondary battery
WO2020118884A1 (en) Wound-type cell, lithium ion secondary battery and negative electrode plate
CN111430801B (en) Electrolyte of lithium ion secondary battery and application thereof
CN115528208B (en) Lithium supplementing negative electrode plate and secondary battery
CN109524714B (en) Lithium ion battery electrolyte and lithium ion battery
CN112635766B (en) Metal lithium battery cathode, preparation method thereof and lithium secondary battery
CN111063932B (en) Electrolyte solution and secondary battery
CN114976218A (en) Composite isolating membrane, preparation method thereof and secondary battery
CN114843698A (en) Composite oil-based diaphragm, preparation method thereof and secondary battery
CN114899412A (en) Electrode structure, preparation method thereof, negative plate and secondary battery
CN114497483A (en) Negative plate, preparation method thereof and lithium ion battery
CN110797572B (en) Lithium ion battery electrolyte and lithium ion battery
CN114361591B (en) Electrolyte and battery
CN109786838B (en) Electrolyte, lithium ion secondary battery and electric vehicle
CN116632349A (en) Lithium ion battery electrolyte and application thereof
CN117239241A (en) Electrolyte and lithium ion battery
CN116565316A (en) Electrolyte additive, electrolyte and application thereof
CN116845370A (en) Lithium ion battery

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination