[go: up one dir, main page]

CN117613278A - Composite current collector and preparation method and application thereof - Google Patents

Composite current collector and preparation method and application thereof Download PDF

Info

Publication number
CN117613278A
CN117613278A CN202311293396.9A CN202311293396A CN117613278A CN 117613278 A CN117613278 A CN 117613278A CN 202311293396 A CN202311293396 A CN 202311293396A CN 117613278 A CN117613278 A CN 117613278A
Authority
CN
China
Prior art keywords
current collector
composite current
layer
flame retardant
negative electrode
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
CN202311293396.9A
Other languages
Chinese (zh)
Inventor
杨山
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.)
Zhejiang Liwei Electronic Technology Co ltd
Original Assignee
Zhejiang Liwei Electronic 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 Zhejiang Liwei Electronic Technology Co ltd filed Critical Zhejiang Liwei Electronic Technology Co ltd
Priority to CN202311293396.9A priority Critical patent/CN117613278A/en
Publication of CN117613278A publication Critical patent/CN117613278A/en
Pending legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/20—Oxides; Hydroxides
    • C08K3/22—Oxides; Hydroxides of metals
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/08—Metals
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • 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
    • H01M4/661—Metal or alloys, e.g. alloy coatings
    • 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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/66—Selection of materials
    • H01M4/668—Composites of electroconductive material and synthetic resins
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/08—Metals
    • C08K2003/085—Copper
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/20—Oxides; Hydroxides
    • C08K3/22—Oxides; Hydroxides of metals
    • C08K2003/2227—Oxides; Hydroxides of metals of aluminium
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K2201/00—Specific properties of additives
    • C08K2201/001—Conductive additives
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K2201/00—Specific properties of additives
    • C08K2201/011—Nanostructured additives
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2201/00—Properties
    • C08L2201/02—Flame or fire retardant/resistant
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2201/00—Properties
    • C08L2201/04—Antistatic
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2203/00—Applications
    • C08L2203/20—Applications use in electrical or conductive gadgets
    • 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

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Medicinal Chemistry (AREA)
  • Composite Materials (AREA)
  • Organic Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Health & Medical Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Cell Electrode Carriers And Collectors (AREA)
  • Secondary Cells (AREA)

Abstract

The invention discloses a composite current collector and a preparation method and application thereof. The composite current collector comprises a high polymer layer, wherein a reinforcing layer and a metal layer are sequentially laminated on the surface of the high polymer layer, the high polymer layer contains a flame retardant and an electric conduction and heat conduction filler, and the mass fractions of the electric conduction and heat conduction filler and the flame retardant in the high polymer layer are respectively M A 、M B ，M A 、M B The following are satisfied: m is more than 0.25 and less than A /M B Less than or equal to 0.72. The composite current collector has good safety performance due to the synergistic effect of the flame retardant and the electric and heat conducting filler, can reduce the internal temperature of the battery to the greatest extent, reduces the risk of thermal runaway, and enhances the safety performance of the battery.

Description

Composite current collector and preparation method and application thereof
Technical Field
The invention belongs to the technical field of batteries, and particularly relates to a composite current collector and a preparation method and application thereof.
Background
A lithium ion battery is a secondary battery (rechargeable battery) that operates mainly by means of lithium ions moving between a positive electrode and a negative electrode. The key materials of the lithium ion battery comprise a positive electrode material, a negative electrode material, electrolyte and a current collector. The current collector is a component for collecting current in the lithium ion battery, and has the main functions of collecting the current generated by the active substances of the battery, providing an electronic channel, accelerating charge transfer and improving charge-discharge coulomb efficiency. The traditional current collector is a metal current collector, and because the rigidity of the traditional metal current collector enables the current collector to be easily broken, burrs are formed to pierce through the diaphragm, so that the internal short circuit of the positive electrode and the negative electrode of the battery is caused, and the safety is poor. In recent years, one of the effective methods for improving the safety of current collectors is to use a polymer-containing current collector to improve the safety performance of the current collector by improving the toughness. However, at present, the safety performance of conventional polymer-containing current collectors is still poor.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems in the prior art described above. Therefore, the invention provides the composite current collector which has the characteristic of good safety performance.
The invention also provides a preparation method of the composite current collector.
The invention also provides a negative pole piece.
The invention also provides a secondary battery.
The invention also provides application of the composite current collector.
The first aspect of the present invention provides a composite current collector, comprising a polymer layer, wherein the surface of the polymer layer is sequentially laminated with a reinforcing layer and a metal layer, the polymer layer contains a flame retardant and an electrically and thermally conductive filler, and the mass fractions of the electrically and thermally conductive filler and the flame retardant in the polymer layer are respectively M A 、M B ，M A 、M B The following are satisfied: m is more than 0.25 and less than A /M B ≤0.72。
The composite current collector provided by the embodiment of the invention has at least the following beneficial effects:
in the polymer layer of the composite current collector, the additive flame retardant is adopted, and the polymer base film is formed by mixing the additive flame retardant with a polymer, so that the base film has flame retardance; however, when only flame retardant is added, the thermal conductivity of the polymer base film is poor, and local overheating is likely to cause battery failure, so that the addition of the electric and heat conductive filler is required to cooperate together. The conductive and heat-conductive filler can improve the heat dissipation capacity of the polymer base film, plays a role in heat transfer and avoids local thermal runaway. The flame retardant and the electric conduction and heat conduction filler are compounded and combined to improve the safety of the battery, the use of a single flame retardant can be reduced by adopting the compounding mode, the electric conduction capacity of the current collector is improved, the charging window of the battery is widened, the safety performance of the lithium ion battery is greatly enhanced, the comprehensive performance of the battery is improved, and the low cost and high efficiency are realized.
The invention adopts the flame retardant with specific mass fraction relation and the electric conduction and heat conduction filler (M is constructed A 、M B Relation formula: m is more than 0.25 and less than A /M B Not more than 0.72), the oxygen index, the heat transfer coefficient and the electric conductivity of the composite current collector are improved through the synergistic effect between the flame retardant and the electric conduction and heat conduction filler, the flame retardant efficiency and the charging capability of the composite current collector are improved, and the composite current collector has good safety performance and excellent performance. The composite current collector is applied to the battery, and the flame retardant and the electric conduction and heat conduction filler have synergistic effect, so that the internal temperature of the battery is reduced to the greatest extent, the thermal runaway risk is reduced, the safety performance of the battery is enhanced, the charging speed of the battery can be enhanced, and the comprehensive performance of the battery is excellent. When the internal temperature of the lithium ion battery is increased, the flame retardant is decomposed to absorb heat, and the electric conduction and heat conduction filler is used for dispersing heat, so that the safety and the electric conductivity of the composite current collector are both obviously improved, and the thermal runaway risk of the battery is reduced.
In addition, since the physical and chemical properties of the polymer layer and the metal layer are different, if the polymer layer and the metal layer are directly contacted, the adhesion force and the bonding fastness between the metal layer and the polymer base film are poor. The poor binding force between the metal layer and the polymer layer can cause serious metal delamination under long-time soaking of the electrolyte, reduce the conductivity of the electrode material, increase the internal resistance of the battery and cause the safety problem of the battery. The reinforcing layer is arranged between the high polymer layer and the metal layer, so that the adhesion of the surface property of the high polymer layer to the metal layer can be improved, the structural stability of the composite current collector is improved, the metal layer is not easy to peel off from the high polymer layer, the high polymer layer is not easy to deform due to heating, the heat resistance of the high polymer layer can be remarkably enhanced, the heat-resistant structural stability of the composite current collector is enhanced, and the composite current collector is not easy to cause thermal runaway or rapid reduction of the conductive performance due to deformation of the high polymer layer caused by high temperature, so that the composite current collector has good safety performance. Specifically: the strengthening layer can improve the bonding force of the interface between the high polymer layer and the metal layer through mechanical interlocking and chemical bonding. For example, when the reinforcing layer contains alumina, the introduction of alumina makes the oxygen of carbonyl group in the high molecular layer and Al atom in the alumina form O-Al strong ionic bond, so that the interface binding force is improved.
In addition, certain tension is usually applied to the winding and unwinding of the coating, rolling and slitting processes in the production process of the battery pole piece, and particularly the pole piece can be stretched to a certain extent under the action of strong mechanical stress of rolling, and when the polymer layer is in direct contact with the metal layer, the pole piece can warp and deform after rolling due to stretching difference between the polymer layer and the metal layer, so that the winding rate of the following process is seriously affected. By arranging the reinforcing layer, the tensile strength of the composite current collector is obviously improved, the influence of tension applied to rolling and unreeling of the composite current collector, mechanical stress of rolling and the like on the current collector in the production process of the pole piece is reduced, and the quality of the pole piece is obviously improved.
In some embodiments of the invention, 0.45 < M A /M B ≤0.55。
In some embodiments of the invention, the electrically and thermally conductive filler comprises at least one of nano silver, nano copper, nano aluminum, silicon carbide, nano tungsten, carbon fiber, graphite, or graphene.
In some embodiments of the invention, the silver is nanosilver; and/or, the copper is nano copper; and/or, the aluminum is nano aluminum; and/or, the tungsten is nano tungsten.
In some embodiments of the invention, the M A 4-8%.
In some embodiments of the invention, the flame retardant comprises at least one of aluminum hydroxide, borax, calcium carbonate, or magnesium hydroxide.
In some embodiments of the invention, the M B 11-15%.
In some embodiments of the invention, the flame retardant has an average particle size D B 100-300nm.
In some embodiments of the invention, the electrically and thermally conductive filler has an average particle size D A 50-150nm.
In some embodiments of the invention, the D A 、D B The following are satisfied: d is more than or equal to 0.4 A /D B ＜1。
By the above embodiment, the specific average particle diameter relationship (0.4.ltoreq.D) is employed in the present invention A /D B The flame retardant and the conductive and heat-conductive filler in the step 1) can better improve the comprehensive performance of the composite current collector, including heat conduction capability and flame retardance: if the flame retardant can enable the polymer layer to have flame retardance, the functions of the electric conduction and heat conduction filler include improving the heat conduction performance of the polymer layer, and a heat transfer process is needed, the electric conduction and heat conduction filler has relatively smaller particle size, larger specific surface area, smaller particle gaps among the electric conduction and heat conduction fillers, and tighter contact and better heat conduction effect are achieved.
Compared with D A Is below 50nm, D B Is less than 100nm, D A 50-150nm, D B When the particle size is 100-300nm, the polymer layer particles are easier to disperse, the particles are more uniformly dispersed, and the composite current collector has better performance. Compared with D A Is 150nm or more, D B Is 300nm or more, D A 50-150nm, D B When the particle size is 100-300nm, the specific surface area of the flame retardant and the conductive filler is smaller, the heat dissipation capacity is stronger, and the flame retardant property of the composite current collector is better.
In some embodiments of the invention, the thickness H, D of the polymeric layer A ＜D B ＜H。
Through the embodiment, the effect of the electric conduction and heat conduction filler comprises improving the heat conduction performance of the high polymer layer, and the heat transfer process is needed, the electric conduction and heat conduction filler has relatively smaller particle size, larger specific surface area, smaller particle gaps among the electric conduction and heat conduction fillers and tighter contact, so that the heat conduction effect is better.
In some embodiments of the invention, the polymeric layer has a thickness of 3-5 μm.
In some embodiments of the present invention, the polymer layer further comprises a polymer material, including, but not limited to: polyethylene, polypropylene, polyimide, fibrous films, and the like.
In some embodiments of the invention, the strengthening layer comprises at least one of magnesium oxide, aluminum oxide.
By the arrangement of the strengthening layer, the surface property of the high polymer layer can be improved, the adhesion of the metal layer can be enhanced, and the high polymer layer is not easy to deform due to heating. Wherein, the strengthening layer can improve the bonding force of the interface between the high polymer layer and the metal layer through mechanical interlocking and chemical bonding. For example, the introduction of alumina enables the oxygen of carbonyl in the high polymer layer and Al atoms in the alumina to form O-Al strong ionic bonds, thereby improving the interface binding force.
In addition, certain tension is usually applied to the winding and unwinding of the coating, rolling and slitting processes in the production process of the battery pole piece, and particularly the pole piece can be stretched to a certain extent under the action of strong mechanical stress of rolling, and when the polymer layer is in direct contact with the metal layer, the pole piece can warp and deform after rolling due to stretching difference between the polymer layer and the metal layer, so that the winding rate of the following process is seriously affected. By arranging the reinforcing layer, the tensile strength of the composite current collector is obviously improved, the influence of tension applied to rolling and unreeling of the composite current collector, mechanical stress of rolling and the like on the current collector in the production process of the pole piece is reduced, and the quality of the pole piece is obviously improved.
In some embodiments of the invention, the strengthening layer has a thickness of 50-100nm.
Through the implementation mode, the thickness of the reinforcement layer is limited to 50-100nm, so that the composite current collector is less prone to wrinkling and curling deformation, and the surface flatness of the composite current collector is further improved.
In some embodiments of the invention, the metal layer comprises at least one of aluminum, copper, nickel, gold, silver, or platinum.
In some embodiments of the invention, the metal layer has a thickness of 0.5-2 μm.
In some embodiments of the present invention, the reinforcement layer and the metal layer are sequentially disposed on both sides of the polymer layer.
In some embodiments of the present invention, the composite current collector includes a first metal layer, a first reinforcement layer, a polymer layer, a second reinforcement layer, and a second metal layer that are stacked.
In some embodiments of the invention, the composite current collector has a thickness of 5-8 μm.
In a second aspect of the present invention, a method for preparing a composite current collector is provided, comprising the steps of: and preparing a reinforcing layer and a metal layer on the surface of the high polymer layer in sequence.
In a third aspect of the present invention, a negative electrode tab is provided, including the above-mentioned composite current collector.
In some embodiments of the invention, the negative electrode tab further comprises a negative electrode active material layer disposed on a surface of the composite current collector.
In some embodiments of the present invention, the negative electrode active material layer includes, but is not limited to, graphite, graphene, silicon carbon material, and the like.
In a fourth aspect of the present invention, a secondary battery is provided, which includes the above-described composite current collector or the above-described negative electrode tab.
In some embodiments of the invention, the secondary battery comprises at least one of a lithium ion battery or a sodium ion battery.
In some embodiments of the invention, the secondary battery further comprises a positive electrode, a separator, and an electrolyte.
In some embodiments of the present invention, the positive electrode tab includes a positive electrode current collector and a positive electrode active material layer provided on a surface of the positive electrode current collector.
In some embodiments of the invention, the positive electrode current collector includes, but is not limited to, aluminum.
In some embodiments of the present invention, the positive electrode active material layer includes, but is not limited to, lithium cobaltate, lithium iron phosphate, lithium manganate, ternary materials, or the like.
In some embodiments of the invention, the separator includes, but is not limited to, a polyolefin separator, a ceramic separator, such as a PE separator containing a ceramic coating.
In some embodiments of the invention, the electrolyte comprises LiPF 6 Ethylene Carbonate (EC), propylene Carbonate (PC), diethyl carbonate (DEC), propyl Propionate (PP).
Drawings
The invention is further described with reference to the accompanying drawings and examples, in which:
fig. 1 is a schematic structural diagram of a composite current collector in embodiment 1 of the present invention.
Reference numerals: 11. a polymer layer; 21. a first reinforcing layer; 22. a second strengthening layer; 31. a first metal layer; 32. a second metal layer; A. an electrically and thermally conductive filler; B. a flame retardant.
Detailed Description
The conception and the technical effects produced by the present invention will be clearly and completely described in conjunction with the embodiments below to fully understand the objects, features and effects of the present invention. It is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments, and that other embodiments obtained by those skilled in the art without inventive effort are within the scope of the present invention based on the embodiments of the present invention.
The experimental procedures, which are not specific to the particular conditions noted in the examples below, are generally performed under conditions conventional in the art or according to manufacturer's recommendations; the raw materials, reagents and the like used, unless otherwise specified, are those commercially available from conventional markets and the like.
Example 1
The embodiment discloses a composite current collector, the structure of which is shown in the schematic diagramAs shown in fig. 1, the laminate comprises a first metal layer 31, a first reinforcing layer 21, a polymer layer 11, a second reinforcing layer 22, and a second metal layer 32, which are laminated to each other, and have thicknesses of 1 μm, 80nm, 4 μm, 80nm, and 1 μm, respectively. Wherein the polymer layer comprises polymer material polypropylene (the molecular weight is 30-40 ten thousand), an electric conduction and heat conduction filler A and a flame retardant B, and the polymer layer comprises: the flame retardant is aluminum hydroxide with average grain diameter D B 200nm and 11% of flame retardant; the electric and heat conductive filler is nano copper and has average grain diameter D A 100nm, and the mass fraction of the electric conduction and heat conduction filler is 4%; in addition, the first metal layer and the second metal layer are copper layers; the first strengthening layer and the second strengthening layer are both alumina.
The embodiment also discloses a negative electrode plate with the thickness of about 76 mu m, which comprises the composite current collector in the embodiment and a negative electrode active material layer arranged on the surface of the composite current collector, wherein the negative electrode active material layer comprises a negative electrode active material. The preparation method of the negative electrode plate comprises the following steps: mixing artificial graphite, a conductive agent Super-P and a binder SBR according to the mass ratio of 97.7:1.1:1.2 to obtain negative electrode slurry, uniformly coating the negative electrode slurry on the composite current collector, and then carrying out cold pressing and slitting to obtain a negative electrode plate.
The embodiment also discloses a lithium ion battery, including the negative pole piece in this embodiment, still include positive pole piece, diaphragm and electrolyte, wherein:
the preparation of the positive pole piece comprises the following steps: mixing lithium cobaltate, a conductive agent acetylene black, a conductive carbon nano tube and a binder PVDF in an N-methyl pyrrolidone solvent system according to a mass ratio of 97.6:0.5:0.6:1.3 to obtain positive electrode slurry, and uniformly coating the positive electrode slurry on an aluminum current collector (4.2 g/cm) 2 ) Then cold pressing and slitting are carried out to obtain a positive pole piece; the thickness of the positive electrode plate is 70 mu m, wherein the thickness of the aluminum current collector is 8 mu m;
isolation film, purchase material coding: DM-SBX-B585-0115 purchased from Ningde Zhuo Gao new material technology Co., ltd., membrane total thickness 7 μm, including PE base membrane and two coating layers with thickness 1.5 μm arranged on two sides of the base membrane, the coating layer components being alumina and PVDF;
the preparation of the electrolyte comprises the following steps: mixing Ethylene Carbonate (EC), propylene Carbonate (PC), diethyl carbonate (DEC) and Propyl Propionate (PP) according to a volume ratio of 1:1:4:4 to obtain a mixed solution, and dissolving fully dried lithium salt LiPF6 in the mixed solution according to a mol/L ratio to prepare an electrolyte.
The preparation of the lithium ion battery comprises the following steps: and winding or laminating the positive pole piece, the isolating film and the negative pole piece to manufacture a bare cell, packaging and injecting electrolyte, and manufacturing the finished lithium ion battery.
Example 2
This example discloses a composite current collector which differs from the composite current collector of example 1 only in that: in the polymer layer of the composite current collector, the mass fraction of the flame retardant is 15%, and the mass fraction of the electric conduction and heat conduction filler is 4%.
The present embodiment also discloses a negative electrode sheet, which differs from the negative electrode sheet of embodiment 1 only in that: the composite current collector in this example was used instead of the composite current collector in example 1.
The present embodiment also discloses a lithium ion battery, which differs from the lithium ion battery of embodiment 1 only in that: the negative electrode sheet in this example was used instead of the negative electrode sheet in example 1.
Example 3
This example discloses a composite current collector which differs from the composite current collector of example 1 only in that: in the polymer layer of the composite current collector, the mass fraction of the flame retardant is 13%, and the mass fraction of the electric conduction and heat conduction filler is 5%.
The present embodiment also discloses a negative electrode sheet, which differs from the negative electrode sheet of embodiment 1 only in that: the composite current collector in this example was used instead of the composite current collector in example 1.
The present embodiment also discloses a lithium ion battery, which differs from the lithium ion battery of embodiment 1 only in that: the negative electrode sheet in this example was used instead of the negative electrode sheet in example 1.
Example 4
This example discloses a composite current collector which differs from the composite current collector of example 1 only in that: in the polymer layer of the composite current collector, the mass fraction of the flame retardant is 12%, and the mass fraction of the electric conduction and heat conduction filler is 6%.
The present embodiment also discloses a negative electrode sheet, which differs from the negative electrode sheet of embodiment 1 only in that: the composite current collector in this example was used instead of the composite current collector in example 1.
The present embodiment also discloses a lithium ion battery, which differs from the lithium ion battery of embodiment 1 only in that: the negative electrode sheet in this example was used instead of the negative electrode sheet in example 1.
Example 5
This example discloses a composite current collector which differs from the composite current collector of example 1 only in that: in the polymer layer of the composite current collector, the mass fraction of the flame retardant is 11%, and the mass fraction of the electric conduction and heat conduction filler is 8%.
The present embodiment also discloses a negative electrode sheet, which differs from the negative electrode sheet of embodiment 1 only in that: the composite current collector in this example was used instead of the composite current collector in example 1.
The present embodiment also discloses a lithium ion battery, which differs from the lithium ion battery of embodiment 1 only in that: the negative electrode sheet in this example was used instead of the negative electrode sheet in example 1.
Example 6
This example discloses a composite current collector which differs from the composite current collector of example 1 only in that: in the polymer layer of the composite current collector of this embodiment: d (D) A /D B > 1; specifically, in this embodiment: d (D) A /D B =1.18, wherein the average particle diameter D of the conductive filler nano copper A Average particle diameter D of flame retardant aluminum hydroxide of 100nm B 85nm.
The present embodiment also discloses a negative electrode sheet, which differs from the negative electrode sheet of embodiment 1 only in that: the composite current collector in this example was used instead of the composite current collector in example 1.
The present embodiment also discloses a lithium ion battery, which differs from the lithium ion battery of embodiment 1 only in that: the negative electrode sheet in this example was used instead of the negative electrode sheet in example 1.
Example 7
This example discloses a composite current collector which differs from the composite current collector of example 1 only in that: d in the polymer layer of the composite current collector of the embodiment A /D B < 0.4; specifically, in this embodiment: d (D) A /D B =0.25, wherein the average particle diameter D of the conductive filler nano copper A Average particle diameter D of flame retardant aluminum hydroxide of 60nm B 240nm.
The present embodiment also discloses a negative electrode sheet, which differs from the negative electrode sheet of embodiment 1 only in that: the composite current collector in this example was used instead of the composite current collector in example 1.
The present embodiment also discloses a lithium ion battery, which differs from the lithium ion battery of embodiment 1 only in that: the negative electrode sheet in this example was used instead of the negative electrode sheet in example 1.
Example 8
This example discloses a composite current collector which differs from the composite current collector of example 1 only in that: the composite current collector of this embodiment does not contain the first reinforcing layer.
The present embodiment also discloses a negative electrode sheet, which differs from the negative electrode sheet of embodiment 1 only in that: the composite current collector in this example was used instead of the composite current collector in example 1.
The present embodiment also discloses a lithium ion battery, which differs from the lithium ion battery of embodiment 1 only in that: the negative electrode sheet in this example was used instead of the negative electrode sheet in example 1.
Comparative example 1
This comparative example discloses a composite current collector which differs from the composite current collector of example 1 only in that: in the polymer layer of the composite current collector of the comparative example, the mass fraction of the flame retardant is 0%, and the mass fraction of the electric conduction and heat conduction filler is 0%.
This comparative example also discloses a negative electrode sheet which differs from the negative electrode sheet of example 1 only in that: the composite current collector in this comparative example was used instead of the composite current collector in example 1.
This comparative example also discloses a lithium ion battery which differs from the lithium ion battery of example 1 only in that: the negative electrode sheet in this comparative example was used instead of the negative electrode sheet in example 1.
Comparative example 2
This comparative example discloses a composite current collector which differs from the composite current collector of example 1 only in that: in the polymer layer of the composite current collector of the comparative example, the mass fraction of the flame retardant is 20%, and the mass fraction of the electric conduction and heat conduction filler is 0%.
This comparative example also discloses a negative electrode sheet which differs from the negative electrode sheet of example 1 only in that: the composite current collector in this comparative example was used instead of the composite current collector in example 1.
This comparative example also discloses a lithium ion battery which differs from the lithium ion battery of example 1 only in that: the negative electrode sheet in this comparative example was used instead of the negative electrode sheet in example 1.
Comparative example 3
This comparative example discloses a composite current collector which differs from the composite current collector of example 1 only in that: in the polymer layer of the composite current collector of the comparative example, the mass fraction of the flame retardant is 9%, and the mass fraction of the electric conduction and heat conduction filler is 8%.
This comparative example also discloses a negative electrode sheet which differs from the negative electrode sheet of example 1 only in that: the composite current collector in this comparative example was used instead of the composite current collector in example 1.
This comparative example also discloses a lithium ion battery which differs from the lithium ion battery of example 1 only in that: the negative electrode sheet in this comparative example was used instead of the negative electrode sheet in example 1.
Comparative example 4
This comparative example discloses a composite current collector which differs from the composite current collector of example 1 only in that: in the polymer layer of the composite current collector of the comparative example, the mass fraction of the flame retardant is 11%, and the mass fraction of the electric conduction and heat conduction filler is 2%.
This comparative example also discloses a negative electrode sheet which differs from the negative electrode sheet of example 1 only in that: the composite current collector in this comparative example was used instead of the composite current collector in example 1.
This comparative example also discloses a lithium ion battery which differs from the lithium ion battery of example 1 only in that: the negative electrode sheet in this comparative example was used instead of the negative electrode sheet in example 1.
Comparative example 5
This comparative example discloses a composite current collector which differs from the composite current collector of example 1 only in that: the first reinforcing layer and the second reinforcing layer were not contained in this comparative example.
This comparative example also discloses a negative electrode sheet which differs from the negative electrode sheet of example 1 only in that: the composite current collector in this comparative example was used instead of the composite current collector in example 1.
This comparative example also discloses a lithium ion battery which differs from the lithium ion battery of example 1 only in that: the negative electrode sheet in this comparative example was used instead of the negative electrode sheet in example 1.
The partial information of the negative electrode sheets of each example and comparative example is shown in Table 1 below:
TABLE 1
Test examples
The performance test is carried out on the lithium ion batteries obtained in the examples and the comparative examples, and the test example specifically comprises the following steps:
carrying out a hot box experiment and a diaphragm resistance test on the lithium ion battery;
the performance test method comprises the following steps: after fully charging the lithium ion battery, placing the lithium ion battery in a high-low temperature oven for heat abuse safety test;
the battery cell capacity is 4600mAh, and the hot box testing method comprises the following steps: charging to 4.5V according to constant current and constant voltage of 0.5C, and keeping the cut-off current at 0.02C; the fully charged battery cells are placed in a high-low temperature oven with a set temperature for 60min. The judging condition is that the fire is not generated and the explosion is not generated. The film resistance test object is the negative pole piece in each example and comparative example, and the test area is 154.025mm 2 。
Adhesive force test: the test object was a composite current collector (negative electrode current collector) in each example and comparative example, and a sample having a width of 15mm and a length of 150mm was clamped on a clamp of a tensile tester at a clamp pulling speed of 10mm/min.
Mechanical tensile Strength test: the test subjects were composite current collectors (negative current collectors) in each example and comparative example, and were tested using a TSE504C type electronic universal tester.
The test results are shown in table 2:
TABLE 2
In the sheet resistance test, the sheet resistance of comparative example 2 was 0.49mΩ, while the sheet resistance of other examples was lower, indicating that the preferred combination of the electrically and thermally conductive filler and the flame retardant was beneficial to improving the electron transport capability of the composite current collector, and can provide good electrical performance for the battery.
In the hot box experiments, examples 1 to 5 all had higher valuesOf the heat box passing temperatures of (C), example 4 gives the best results (M A /M B =0.5), while comparative examples 1-2 passed through a lower hot box temperature, indicating that the cells of comparative examples 1-2 are more prone to failure, the safety factor is the lowest, and the amount of flame retardant used in comparative example 2 is as high as 20%, indicating that a single addition of flame retardant requires a greater amount to achieve a certain effect, and the effect is poor (e.g., flame retardant properties, conductivity properties are significantly inferior to those of examples 1-5). Therefore, the flame retardant and the heat and electric conductive agent in the composite current collector are added at the same time, so that the safety and the current conductivity of the current collector are obviously improved, the composite current collector has better safety performance, and the composite current collector has better thermal stability when the battery generates larger heat.
As can be seen from examples 1 and 8 and comparative example 5, the arrangement of the reinforcing layer significantly increases the adhesion between the polymer layer and the metal layer and the tensile strength of the mechanical properties of the composite current collector, which is beneficial to reducing the influence of the tension applied to the winding and unwinding of the composite current collector and the mechanical stress of rolling and the like on the current collector in the production process of the pole piece, and significantly improves the quality of the pole piece.
Wherein the composite current collector of comparative example 3 uses the same thickness of the reinforcing layer and the metal layer as those of examples 1 to 5, and has a relatively small internal resistance as measured by adding a relatively large amount of the electrically and thermally conductive agent, but has a relatively small amount of M as the flame retardant A /M B =0.89 > 0.72, affecting the performance of thermal abuse, the passing temperature of the hot box was measured to be significantly lower than in examples 1-5.
In summary, in the composite current collector, the flame retardant efficiency and the current collector charging capability are improved through the synergistic effect of the flame retardant and the electric conduction and heat conduction filler and the optimal combination of the flame retardant and the electric conduction and heat conduction filler. When the composite current collector is applied to a battery, the flame retardant and the electric conduction and heat conduction filler are synergistic to reduce the temperature rise of the battery, reduce the risk of thermal runaway and enhance the safety performance and the charging speed of the battery. When the internal temperature of the lithium ion battery is increased, the flame retardant is decomposed to absorb heat, and the heat is dissipated by the electric conduction and heat conduction filler, so that the safety and the electric conduction coefficient of the composite current collector are both obviously improved.
The "room temperature" and "normal temperature" herein are about 25 ℃ unless otherwise specified; the meaning of "about" with respect to a numerical value herein is an error of + -2%.
The foregoing examples illustrate only a few embodiments of the invention and are described in detail herein without thereby limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention.

Claims (10)

1. The composite current collector is characterized by comprising a polymer layer, wherein a reinforcing layer and a metal layer are sequentially laminated on the surface of the polymer layer, the polymer layer contains a flame retardant and an electric conduction and heat conduction filler, and the mass fractions of the electric conduction and heat conduction filler and the flame retardant in the polymer layer are M respectively A 、M B ，M A 、M B The following are satisfied: m is more than 0.25 and less than A /M B ≤0.72。
2. The composite current collector of claim 1 wherein said electrically and thermally conductive filler comprises at least one of nanosilver, nanosilver copper, nanosilver aluminum, silicon carbide, nanosungsten, carbon fiber, graphite, or graphene; and/or, the M A 4-8%.
3. The composite current collector of claim 1, wherein said flame retardant comprises at least one of aluminum hydroxide, borax, calcium carbonate, or magnesium hydroxide; and/or, the M B 11-15%.
4. The composite current collector of claim 1 wherein said electrically and thermally conductive filler has an average particle size D A 50-150nm; and/or the average particle diameter D of the flame retardant B 100-300nm; and/or, the D A 、D B The following are satisfied: d is more than or equal to 0.4 A /D B ＜1。
5. The composite current collector of claim 1 wherein said polymeric layer has a thickness of 3-5 μm.
6. The composite current collector of claim 1 wherein said strengthening layer comprises at least one of magnesium oxide, aluminum oxide; and/or the thickness of the strengthening layer is 50-100nm.
7. The composite current collector of claim 1 wherein said metal layer comprises at least one of aluminum, copper, nickel, gold, silver, or platinum; and/or the thickness of the metal layer is 0.5-2 μm.
8. The composite current collector of claim 1 wherein the reinforcement layer and the metal layer are sequentially disposed on both sides of the polymeric layer.
9. A negative electrode sheet comprising the composite current collector of any one of claims 1-8.
10. A secondary battery comprising the composite current collector according to any one of claims 1 to 8 or the negative electrode tab according to claim 9.
CN202311293396.9A 2023-10-07 2023-10-07 Composite current collector and preparation method and application thereof Pending CN117613278A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202311293396.9A CN117613278A (en) 2023-10-07 2023-10-07 Composite current collector and preparation method and application thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202311293396.9A CN117613278A (en) 2023-10-07 2023-10-07 Composite current collector and preparation method and application thereof

Publications (1)

Publication Number Publication Date
CN117613278A true CN117613278A (en) 2024-02-27

Family

ID=89950448

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202311293396.9A Pending CN117613278A (en) 2023-10-07 2023-10-07 Composite current collector and preparation method and application thereof

Country Status (1)

Country Link
CN (1) CN117613278A (en)

Similar Documents

Publication Publication Date Title
CN113410432B (en) Negative plate, preparation method and lithium ion battery comprising negative plate
CN111900392B (en) A positive electrode sheet and a lithium ion battery containing the positive electrode sheet
CN111697230B (en) High-safety composite positive plate, preparation method thereof and lithium ion battery using high-safety composite positive plate
WO2020098671A1 (en) Positive electrode plate and electrochemical device
CN112331905A (en) High-safety lithium ion battery and preparation method thereof
WO2020098797A1 (en) Positive electrode plate and electrochemical device
WO2020098788A1 (en) Positive pole piece and electrochemical apparatus
CN112018326A (en) Negative plate and lithium ion battery comprising same
CN116315459B (en) Separator, electrochemical device, and electronic apparatus
EP4086978A1 (en) Welding-free connector electrically connected to battery cell, and lithium ion battery comprising the connector
WO2020098770A1 (en) Positive electrode piece and electrochemical device
CN111640949A (en) Current collector, electrode plate, electrochemical device and electronic device
CN114242932A (en) A lithium-ion battery
WO2025130263A1 (en) Electrode sheet and battery
WO2023098646A1 (en) Separator and battery comprising same
CN108987705B (en) An electrode material composition, a lithium ion battery positive electrode sheet and a lithium ion battery
CN113113603A (en) Lithium ion battery electrode plate, preparation method thereof and lithium ion battery
EP3975281B1 (en) Isolation membrane and preparation method therefor, lithium ion secondary battery, battery module, battery pack, and apparatus
CN108511680B (en) Positive plate, preparation method thereof and energy storage device
CN112151757A (en) Negative plate with multilayer film structure and mixed solid-liquid electrolyte lithium storage battery thereof
CN117613278A (en) Composite current collector and preparation method and application thereof
WO2024014374A1 (en) Fluorine resin film for battery outer packaging, battery outer packaging, and secondary battery
CN116914083A (en) A battery and electrical equipment
CN112864364B (en) Positive plate containing high extension layer and lithium ion battery comprising positive plate
CN114284467A (en) Electronic insulator refractory material and application thereof in high-safety 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