WO2024060176A1 - 复合集流体及其制作方法、电极片、二次电池和用电装置 - Google Patents

复合集流体及其制作方法、电极片、二次电池和用电装置 Download PDF

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WO2024060176A1
WO2024060176A1 PCT/CN2022/120745 CN2022120745W WO2024060176A1 WO 2024060176 A1 WO2024060176 A1 WO 2024060176A1 CN 2022120745 W CN2022120745 W CN 2022120745W WO 2024060176 A1 WO2024060176 A1 WO 2024060176A1
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conductive polymer
polymer layer
current collector
conductive
composite current
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PCT/CN2022/120745
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English (en)
French (fr)
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郑义
孙成栋
刘义修
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宁德时代新能源科技股份有限公司
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Priority to PCT/CN2022/120745 priority Critical patent/WO2024060176A1/zh
Publication of WO2024060176A1 publication Critical patent/WO2024060176A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • 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

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  • the present application relates to the technical field of lithium batteries, and in particular to a positive active material, a secondary battery and an electrical device.
  • lithium-ion batteries are widely used in energy storage power systems such as hydraulic, thermal, wind and solar power stations, as well as power tools, electric bicycles, electric motorcycles, electric vehicles, Military equipment, aerospace and other fields. Due to the great development of lithium-ion batteries, higher requirements have been put forward for their energy density, cycle performance and safety performance.
  • the electrode sheet of a lithium-ion battery is mainly composed of a current collector and an electrode active material layer disposed on the surface of the current collector.
  • the current collector is mainly made of metal foil, which plays a role in conducting current in the electrode sheet.
  • the thickness of the current collector will affect the energy density of the electrode sheet, so it is required to be as thin as possible.
  • the current production process of lithium-ion batteries requires stretching, rolling, winding and other processes, there is a risk of production breakage after the metal foil is thinned.
  • the actual application process of the prepared lithium-ion batteries there will also be the problem of insufficient overcurrent capability.
  • This application was made in view of the above-mentioned problems, and its purpose is to provide a composite current collector and a manufacturing method thereof, an electrode sheet, a secondary battery, and an electrical device.
  • the first aspect of the present application provides a composite current collector, which comprises a metal foil, wherein the metal foil includes a first surface and a second surface positioned opposite to each other, the first surface is provided with a first conductive polymer layer, and the second surface is provided with a second conductive polymer layer, the material composition of the first conductive polymer layer and the second conductive polymer layer are the same or different, and both contain a polymer material and a conductive agent.
  • the second aspect of the application also provides a preparation method of a composite current collector, including the following steps:
  • first surface and the second surface are opposite to each other, and the materials of the first conductive polymer layer and the second conductive polymer layer are the same or different.
  • a third aspect of the present application also provides an electrode sheet, including a current collector and an electrode film layer disposed on at least one surface of the current collector; the current collector is the composite current collector described in the first aspect or the second aspect.
  • the composite current collector is prepared by the above preparation method.
  • a fourth aspect of the present application also provides a secondary battery, including the electrode sheet described in the third aspect.
  • a fifth aspect of the present application also provides an electrical device, including the secondary battery described in the fourth aspect.
  • Figure 1 is a schematic structural diagram of a composite current collector according to an embodiment of the present application.
  • Figure 2 is a schematic diagram of a secondary battery according to an embodiment of the present application.
  • Figure 3 is an exploded view of the secondary battery according to an embodiment of the present application shown in Figure 2;
  • FIG. 4 is a schematic diagram of a battery module according to an embodiment of the present application.
  • FIG. 5 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG 6 is an exploded view of the battery pack according to an embodiment of the present application shown in Figure 4;
  • Figure 7 is a schematic diagram of an electrical device using a secondary battery as a power source according to an embodiment of the present application.
  • Ranges disclosed herein are defined in terms of lower and upper limits. A given range is defined by selecting a lower limit and an upper limit that define the boundaries of the particular range. Ranges defined in this manner may be inclusive or exclusive of the endpoints, and may be combined in any combination, i.e., any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, understand that ranges of 60-110 and 80-120 are also expected. Furthermore, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2- 3, 2-4 and 2-5.
  • the numerical range “a-b” represents an abbreviated representation of any combination of real numbers between a and b, where a and b are both real numbers.
  • the numerical range “0-5" means that all real numbers between "0-5" have been listed in this article, and "0-5" is just an abbreviation of these numerical combinations.
  • a certain parameter is an integer ⁇ 2
  • the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially.
  • step (c) means that step (c) may be added to the method in any order.
  • the method may include steps (a), (b) and (c). , may also include steps (a), (c) and (b), may also include steps (c), (a) and (b), etc.
  • the “include” and “comprising” mentioned in this application represent open-ended or closed-ended expressions.
  • the “include” and “comprising” may represent that other components not listed may also be included or only the listed components may be included or only the listed components may be included.
  • the term "or” is inclusive.
  • the phrase “A or B” means “A, B, or both A and B”. More specifically, any of the following conditions satisfies the condition "A or B”: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).
  • thinning and thinning of current collectors is the main trend under the current demand for high energy density of batteries.
  • metal foils are prone to risks of strip breakage during the production process and insufficient overcurrent capacity in applications.
  • the present application provides a composite current collector, as shown in Figure 1, which includes a metal foil 100.
  • the metal foil 100 includes a first surface and a second surface that are oppositely positioned, and the first surface is provided with a first conductive polymer layer. 200.
  • the second surface is provided with a second conductive polymer layer 300.
  • the first conductive polymer layer 200 and the second conductive polymer layer 300 have the same or different material compositions, and both include polymer materials and conductive agents.
  • the above-mentioned composite current collector is provided with conductive polymer layers on both surfaces of the metal foil.
  • the presence of the conductive polymer layer effectively increases the tensile strength of the current collector and improves the problem of metal foil interruption during the production process of lithium-ion batteries. , and at the same time, it is convenient to thin the metal foil or use a thinner metal foil to increase the energy density of the electrode sheet.
  • the presence of the conductive polymer layer can isolate the electrolyte and reduce or avoid corrosion of the metal foil by the electrolyte.
  • the first conductive polymer layer 200 covers the entire first surface.
  • the second conductive polymer layer 300 covers the entire second surface.
  • first conductive polymer layer 200 and the second conductive polymer layer 300 are disposed on the outermost layer of the entire composite current collector.
  • the thickness of the first conductive polymer layer 200 ranges from 0.5 ⁇ m to 100 ⁇ m. Below this thickness, the tensile properties of the metal foil can be improved and the energy density of the electrode sheet can be ensured. Specifically, the thickness of the first conductive polymer layer 200 includes, but is not limited to: 0.5 ⁇ m, 0.7 ⁇ m, 1 ⁇ m, 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 8 ⁇ m, 9 ⁇ m, 10 ⁇ m, 20 ⁇ m, 50 ⁇ m, 80 ⁇ m, 90 ⁇ m. ,95 ⁇ m,100 ⁇ m.
  • the polymer material of the first conductive polymer layer 200 includes a thermoplastic polymer.
  • the thermoplastic polymer is an electrolyte-resistant polymer.
  • the thermoplastic polymer includes one or more of PP, PE, PI, PAI, PVDF, SBR, NBR and PTFE.
  • the conductive agent in the material of the first conductive polymer layer 200, includes one or more of SP, Ketjen Black, CNT and graphene.
  • the mass ratio of the polymer material to the conductive agent is (0.05 ⁇ 10):1.
  • the mass ratio of the polymer material to the conductive agent includes but is not limited to: 0.05:1, 0.1:1, 0.5:1, 0.8:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4 :1, 1.5:1, 1.6:1, 1.7:1, 2:1, 3:1, 5:1, 7:1, 10:1.
  • the thickness of the second conductive polymer layer 300 ranges from 0.5 ⁇ m to 100 ⁇ m. Below this thickness, the tensile properties of the metal foil can be improved and the energy density of the electrode sheet can be ensured.
  • the thickness of the first conductive polymer layer 200 includes, but is not limited to: 0.5 ⁇ m, 0.7 ⁇ m, 1 ⁇ m, 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 8 ⁇ m, 9 ⁇ m, 10 ⁇ m, 20 ⁇ m, 50 ⁇ m, 80 ⁇ m, 90 ⁇ m. ,95 ⁇ m,100 ⁇ m.
  • the polymer material of the second conductive polymer layer 300 includes a thermoplastic polymer.
  • the thermoplastic polymer is an electrolyte-resistant polymer.
  • the thermoplastic polymer includes one or more of PP, PE, PI, PAI, PVDF, SBR, NBR and PTFE.
  • the conductive agent in the material of the second conductive polymer layer 300, includes one or more of SP, Ketjen Black, CNT and graphene.
  • the mass ratio of the polymer material to the conductive agent is (0.05 ⁇ 10):1.
  • the mass ratio of the polymer material to the conductive agent includes but is not limited to: 0.05:1, 0.1:1, 0.5:1, 0.8:1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4 :1, 1.5:1, 1.6:1, 1.7:1, 2:1, 3:1, 5:1, 7:1, 10:1.
  • first conductive polymer layer 200 and the second conductive polymer layer 300 are the same or different.
  • the thicknesses of the first conductive polymer layer 200 and the second conductive polymer layer 300 are the same or different.
  • the metal foil 100 has a thickness of 1 ⁇ m to 50 ⁇ m. Combining the first conductive polymer layer 200 and the second conductive polymer layer 300 below this thickness can not only further improve the breakage problem of the metal foil, but also ensure the energy density of the electrode sheet.
  • the thickness of the metal foil 100 includes, but is not limited to: 1 ⁇ m, 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, 5 ⁇ m, 6 ⁇ m, 7 ⁇ m, 8 ⁇ m, 9 ⁇ m, 1 ⁇ m, 10 ⁇ m, 20 ⁇ m, 30 ⁇ m, and 50 ⁇ m.
  • the first conductive polymer layer 200 is provided with a plurality of holes. Further, the pore diameter is 0.1 ⁇ m to 5 ⁇ m. Through the arrangement of the holes, the subsequently prepared electrode film layer and the first conductive polymer layer 200 can be closely combined, thereby reducing the internal resistance of the battery.
  • the second conductive polymer layer 300 is provided with a plurality of holes. Further, the pore diameter is 0.1 ⁇ m to 5 ⁇ m. Through the arrangement of the holes, the subsequently prepared electrode film layer and the second conductive polymer layer 300 can be closely combined, thereby reducing the internal resistance of the battery.
  • the metal foil is copper foil, and the composite current collector has a tensile force at break of ⁇ 200 N; the metal foil is aluminum foil, and the composite current collector has a tensile force at break of ⁇ 80 N.
  • This application also provides a method for preparing a composite current collector, which includes the following steps:
  • first surface and the second surface are opposite to each other, and the materials of the first conductive polymer layer and the second conductive polymer layer are the same or different.
  • step (a) the mixing method is melting and kneading, and the film-forming treatment method is to melt the obtained mixture and then form a film.
  • the film-forming methods include casting, film blowing, etc.
  • the melting and mixing equipment can use a screw extruder.
  • the composite method is independently selected from one of the following methods:
  • the conductive polymer adhesive includes acrylate modified conductive glue, epoxy modified conductive glue, PI conductive glue and PI modified One or more conductive adhesives.
  • methods (1) and (2) can be adaptively selected according to the type of polymer material or existing production equipment, and both can achieve the purpose of compounding. Compared with method (2), which introduces a conductive polymer adhesive, method (1) direct hot pressing lamination is more convenient and economical, and the energy density is also higher.
  • a step of performing a hole-forming treatment on the first conductive polymer layer and the second conductive polymer layer is further included.
  • the pore-forming treatment method can be exemplified by wet pore-forming. Wet pore formation uses a pore-forming agent and the material of the first conductive polymer layer or the second conductive polymer layer to be mixed at high temperature to form a homogeneous solution, and then the temperature is lowered to separate the two phases, and then the pore-forming agent is extracted and removed. This creates holes.
  • the pore-forming agent can be exemplified by paraffin oil.
  • the mass ratio of the pore former to the material of the first conductive polymer layer or the second conductive polymer layer is 100:(150-250).
  • the present application also provides an electrode sheet, including a current collector and an electrode film layer disposed on at least one surface of the current collector; the current collector is a composite current collector prepared by the above preparation method. fluid.
  • the electrode piece is a positive electrode piece or a negative electrode piece, and accordingly, the current collector is a positive electrode current collector or a negative electrode current collector.
  • a secondary battery is provided.
  • a secondary battery typically includes a positive electrode plate, a negative electrode plate, an electrolyte and a separator.
  • active ions are inserted and detached back and forth between the positive and negative electrodes.
  • the electrolyte plays a role in conducting ions between the positive and negative electrodes.
  • the isolation film is placed between the positive electrode piece and the negative electrode piece. It mainly prevents the positive and negative electrodes from short-circuiting and allows ions to pass through.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector.
  • the positive electrode film layer includes a positive electrode active material.
  • the positive electrode current collector has two surfaces opposite to each other in its thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposite surfaces of the positive electrode current collector.
  • the metal material of the metal foil used in the positive electrode current collector includes but is not limited to aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, etc.
  • the cathode active material may include cathode active materials known in the art for batteries.
  • the cathode active material may include at least one of the following materials: an olivine-structured lithium-containing phosphate, a lithium transition metal oxide, and their respective modified compounds.
  • the present application is not limited to these materials, and other traditional materials that can be used as positive electrode active materials of batteries can also be used. Only one type of these positive electrode active materials may be used alone, or two or more types may be used in combination.
  • lithium transition metal oxides may include, but are not limited to, lithium cobalt oxides (such as LiCoO 2 ), lithium nickel oxides (such as LiNiO 2 ), lithium manganese oxides (such as LiMnO 2 , LiMn 2 O 4 ), lithium Nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1/3 Co 1/3 Mn 1/3 O 2 (also referred to as NCM 333 ), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (can also be abbreviated to NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (can also be abbreviated to NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (can also be abbreviated to NCM 622 ), LiNi At least one of 0.8 Co 0.1 Mn 0.1 O 2 (also referred to as NCM 811 ), lithium nickel cobalt aluminum oxide (such as Li Li
  • the olivine structure contains Examples of lithium phosphates may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also referred to as LFP)), composites of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), lithium manganese phosphate and carbon. At least one of composite materials, lithium iron manganese phosphate, and composite materials of lithium iron manganese phosphate and carbon.
  • the weight ratio of the positive electrode active material in the positive electrode film layer is 80-100% by weight, based on the total weight of the positive electrode film layer count.
  • the positive electrode film layer optionally further includes a binder.
  • the binder may include polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene At least one of ethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer and fluorine-containing acrylate resin.
  • the weight ratio of the binder in the positive electrode film layer is 0-20% by weight, based on the total weight of the positive electrode film layer.
  • the positive electrode film layer optionally further includes a conductive agent.
  • the conductive agent may include at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the weight ratio of the conductive agent in the positive electrode film layer is 0-20% by weight, based on the total weight of the positive electrode film layer.
  • the positive electrode sheet can be prepared by dispersing the above-mentioned components for preparing the positive electrode sheet, such as positive active material, conductive agent, binder and any other components in a solvent (such as N -methylpyrrolidone), forming a positive electrode slurry, wherein the solid content of the positive electrode slurry is 40-80wt%, the viscosity at room temperature is adjusted to 5000-25000mPa ⁇ s, and the positive electrode slurry is coated on the surface of the positive electrode current collector , dried and cold pressed by a cold rolling mill to form a positive electrode piece; the unit area density of the positive electrode powder coating is 150-350mg/m 2 , and the compacted density of the positive electrode piece is 3.0-3.6g/cm 3 , optionally 3.3 -3.5g/cm 3 .
  • the calculation formula of the compacted density is
  • Compaction density coating surface density / (thickness of electrode piece after extrusion - thickness of current collector).
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer disposed on at least one surface of the negative electrode current collector, where the negative electrode film layer includes a negative electrode active material.
  • the negative electrode current collector has two opposite surfaces in its own thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposite surfaces of the negative electrode current collector.
  • the metal material of the metal foil used for the negative electrode current collector includes, but is not limited to, copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver, silver alloy, etc.
  • the negative active material may be a negative active material known in the art for batteries.
  • the negative active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate, and the like.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon carbon composites, silicon nitrogen composites and silicon alloys.
  • the tin-based material may be selected from at least one of elemental tin, tin oxide compounds and tin alloys.
  • the present application is not limited to these materials, and other traditional materials that can be used as battery negative electrode active materials can also be used. Only one type of these negative electrode active materials may be used alone, or two or more types may be used in combination.
  • the weight ratio of the negative active material in the negative electrode film layer is 70-100% by weight, based on the total weight of the negative electrode film layer.
  • the negative electrode film layer optionally further includes a binder.
  • the binder can be selected from styrene-butadiene rubber (SBR), polyacrylic acid (PAA), polysodium acrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), poly At least one of methacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • SBR styrene-butadiene rubber
  • PAA polyacrylic acid
  • PAAS polysodium acrylate
  • PAM polyacrylamide
  • PVA polyvinyl alcohol
  • SA sodium alginate
  • PMAA methacrylic acid
  • CMCS carboxymethyl chitosan
  • the negative electrode film layer optionally further includes a conductive agent.
  • the conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the weight ratio of the conductive agent in the negative electrode film layer is 0-20% by weight, based on the total weight of the negative electrode film layer.
  • the negative electrode film layer optionally includes other auxiliaries, such as thickeners (such as sodium carboxymethylcellulose (CMC-Na)) and the like.
  • the weight ratio of the other additives in the negative electrode film layer is 0-15% by weight, based on the total weight of the negative electrode film layer.
  • the negative electrode sheet can be prepared by dispersing the above-mentioned components for preparing the negative electrode sheet, such as negative active materials, conductive agents, binders and any other components in a solvent (such as deionized water), forming a negative electrode slurry, wherein the solid content of the negative electrode slurry is 30-70wt%, and the viscosity at room temperature is adjusted to 2000-10000mPa ⁇ s; the obtained negative electrode slurry is coated on the negative electrode current collector, After the drying process and cold pressing, such as against rollers, the negative electrode piece is obtained.
  • the negative electrode powder coating unit area density is 75-220mg/m 2
  • the negative electrode plate compacted density is 1.2-2.0g/m 3 .
  • the electrolyte plays a role in conducting ions between the positive and negative electrodes.
  • the type of electrolyte in this application can be selected according to needs.
  • the electrolyte can be liquid, gel, or completely solid.
  • the electrolyte is an electrolyte solution.
  • the electrolyte solution includes electrolyte salts and solvents.
  • the electrolyte salt may be selected from lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium perchlorate (LiClO 4 ), lithium hexafluoroarsenate (LiAsF 6 ), bisfluorosulfonyl Lithium amine (LiFSI), lithium bistrifluoromethanesulfonyl imide (LiTFSI), lithium trifluoromethanesulfonate (LiTFS), lithium difluoromethanesulfonate borate (LiDFOB), lithium difluoromethane borate (LiBOB), lithium difluorophosphate (LiPO 2 F 2 ), lithium difluorodioxalate phosphate (LiDFOP) and lithium tetrafluorooxalate phosphate (LiTFOP).
  • the concentration of the electrolyte salt is usually 0.5-5mol/L.
  • the solvent may be selected from fluoroethylene carbonate (FEC), ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC) ), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butylene carbonate (BC), methyl formate (MF), methyl acetate Ester (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propyl propionate (PP), methyl butyrate (MB) , one or more of ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS) and diethyl
  • FEC
  • the electrolyte optionally further includes additives.
  • additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain properties of the battery, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.
  • the secondary battery further includes a separator film.
  • a separator film There is no particular restriction on the type of isolation membrane in this application. Any well-known porous structure isolation membrane with good chemical stability and mechanical stability can be used.
  • the material of the isolation membrane can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the isolation film can be a single-layer film or a multi-layer composite film, with no special restrictions. When the isolation film is a multi-layer composite film, the materials of each layer can be the same or different, and there is no particular limitation.
  • the thickness of the isolation film is 6-40 ⁇ m, optionally 12-20 ⁇ m.
  • the positive electrode piece, the negative electrode piece and the separator film can be made into an electrode assembly through a winding process or a lamination process.
  • the secondary battery may include an outer packaging.
  • the outer packaging can be used to package the above-mentioned electrode assembly and electrolyte.
  • the outer packaging of the secondary battery may be a hard shell, such as a hard plastic shell, an aluminum shell, a steel shell, etc.
  • the outer packaging of the secondary battery may also be a soft bag, such as a bag-type soft bag.
  • the material of the soft bag may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, polybutylene succinate, and the like.
  • FIG. 2 shows a square-structured secondary battery 5 as an example.
  • the outer package may include a housing 51 and a cover 53 .
  • the housing 51 may include a bottom plate and side plates connected to the bottom plate, and the bottom plate and the side plates enclose a receiving cavity.
  • the housing 51 has an opening communicating with the accommodation cavity, and the cover plate 53 can cover the opening to close the accommodation cavity.
  • the positive electrode piece, the negative electrode piece and the isolation film can be formed into the electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the containing cavity.
  • the electrolyte soaks into the electrode assembly 52 .
  • the number of electrode assemblies 52 contained in the secondary battery 5 can be one or more, and those skilled in the art can select according to specific actual needs.
  • secondary batteries can be assembled into battery modules, and the number of secondary batteries contained in the battery module can be one or more. The specific number can be selected by those skilled in the art according to the application and capacity of the battery module.
  • FIG. 4 is a battery module 4 as an example.
  • a plurality of secondary batteries 5 may be arranged in sequence along the length direction of the battery module 4 .
  • the plurality of secondary batteries 5 can be fixed by fasteners.
  • the battery module 4 may further include a housing having a receiving space in which a plurality of secondary batteries 5 are received.
  • the above-mentioned battery modules can also be assembled into a battery pack.
  • the number of battery modules contained in the battery pack can be one or more. Those skilled in the art can select the specific number according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box.
  • the battery box includes an upper box 2 and a lower box 3 .
  • the upper box 2 can be covered with the lower box 3 and form a closed space for accommodating the battery module 4 .
  • Multiple battery modules 4 can be arranged in the battery box in any manner.
  • the present application also provides an electrical device, which includes at least one of the secondary battery, battery module, or battery pack provided by the present application.
  • the secondary battery, battery module, or battery pack may be used as a power source for the electrical device, or may be used as an energy storage unit for the electrical device.
  • the electric device may include mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, and electric golf carts). , electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but are not limited to these.
  • a secondary battery, a battery module or a battery pack can be selected according to its usage requirements.
  • Fig. 7 is an electrical device as an example.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, etc.
  • a battery pack or battery module can be used.
  • the device may be a mobile phone, a tablet, a laptop, etc.
  • the device is usually required to be thin and light, and a secondary battery can be used as a power source.
  • conductive polymer films 200 and 300 Preparation of conductive polymer films 200 and 300: PP is used as the polymer material, and the conductive agents are SP, Ketjen Black and graphene. The mass ratio is 60%: 25%: 10%: 5%; use a screw extruder to mix After refining and granulating, it is melted and cast into a conductive film with a thickness of 4 ⁇ m;
  • the metal foil 100 used is aluminum foil with a thickness of 7 ⁇ m;
  • the conductive polymer films 200 and 300 prepared above are used on both sides of the aluminum foil to cover the entire surface.
  • the composite method is hot pressing.
  • the conditions are: Plasma activation treatment is performed on both sides of the aluminum foil, and the conductive polymer films 200 and 300 are covered before proceeding. Multi-roller lamination, hot pressing temperature is 165°C.
  • PE is used as the polymer material, and the conductive agents are SP, Ketjen Black and graphene, with a mass ratio of 55%: 28%: 11%: 6%;
  • a screw extruder is used to mix and manufacture the conductive polymer film 200. After granulation, it is melted and blown into a conductive film with a thickness of 5 ⁇ m;
  • the metal foil 100 used is copper foil with a thickness of 5 ⁇ m;
  • conductive polymer film 300 PP is used as the polymer material, and the conductive agents are SP, Ketjen Black and graphene, with a mass ratio of 60%: 25%: 10%: 5%; a screw extruder is used to mix and manufacture After granulation, it is melted and cast into a conductive film with a thickness of 5 ⁇ m;
  • the composite method is hot pressing.
  • the conditions are: perform Plasma activation treatment on both sides of the copper foil, and cover the conductive polymer films 200 and 300 respectively.
  • the sequence is to first laminate 200 conductive polymer films with a hot pressing temperature of 120°C, and then laminate 300 conductive polymer films with a hot pressing temperature of 165°C.
  • PE is used as the polymer material, and the conductive agents are SP, CNT and graphene.
  • the mass ratio is 55%: 28%: 11%: 6%; after mixing and granulating using a screw extruder Melt and blow into a conductive film with a thickness of 6 ⁇ m;
  • the metal foil 100 used is aluminum foil with a thickness of 5 ⁇ m;
  • conductive polymer film 300 PP is used as the polymer material, and the conductive agents are SP, CNT and graphene.
  • the mass ratio is 60%: 25%: 10%: 5%; after mixing and granulating using a screw extruder Melt and cast into a conductive film with a thickness of 4 ⁇ m;
  • the composite method is hot pressing.
  • the conditions are: perform Plasma activation treatment on both sides of the aluminum foil, and cover the conductive polymer films 200 and 300 respectively.
  • the order is as follows: first laminate 200 pieces of conductive polymer film, the hot pressing temperature is 120°C, and then laminate 300 pieces of conductive polymer film, and the hot pressing temperature is 165°C.
  • PE is used as the polymer material, and the conductive agents are SP, Ketjen Black and graphene, with a mass ratio of 55%: 28%: 11%: 6%;
  • a screw extruder is used to mix and manufacture the conductive polymer film 200. After granulation, it is melted and blown into a conductive film with a thickness of 5 ⁇ m;
  • the metal foil 100 used is copper foil with a thickness of 6 ⁇ m;
  • conductive polymer film 300 PP is used as the polymer material, and the conductive agents are SP, Ketjen Black and graphene, with a mass ratio of 60%: 25%: 10%: 5%; a screw extruder is used to mix and manufacture After granulation, it is melted and cast into a conductive film with a thickness of 4 ⁇ m;
  • the composite method is hot pressing.
  • the conditions are: perform Plasma activation treatment on both sides of the copper foil, and cover the conductive polymer films 200 and 300 respectively.
  • the sequence is as follows: first laminate 200 pieces of conductive polymer film, the hot pressing temperature is 120°C, and then laminate 300 pieces of conductive polymer film, the hot pressing temperature is 165°C.
  • conductive polymer films 200 and 300 Preparation of conductive polymer films 200 and 300: PP is used as the polymer material, and the conductive agents are SP, Ketjen Black and graphene. The mass ratio is 60%: 25%: 10%: 5%; use a screw extruder to mix After refining and granulating, it is melted and cast into a conductive film with a thickness of 4 ⁇ m;
  • the metal foil 100 used is aluminum foil with a thickness of 7 ⁇ m;
  • the conductive polymer films 200 and 300 prepared above are used on both sides of the aluminum foil to cover the entire surface.
  • the composite method is bonded by a conductive polymer adhesive.
  • the conditions are: using a sandwich composite process, the PI conductive adhesives are extruded on The aluminum foil and the conductive polymer film 200, and the aluminum foil and the conductive polymer film 300 are bonded by reaction and solidification after roller lamination.
  • PE is used as the polymer material, and the conductive agents are SP, CNT and graphene.
  • the mass ratio is 55%: 28%: 11%: 6%; after mixing and granulating using a screw extruder Melt and cast into a conductive film with a thickness of 6 ⁇ m;
  • the metal foil 100 used is aluminum foil with a thickness of 5 ⁇ m;
  • PP is used as the polymer material
  • SP, CNT and graphene are used as the conductive agents, with a mass ratio of 60%:25%:10%:5%
  • a screw extruder is used to mix and granulate, and then melted and cast into a conductive film with a thickness of 4 ⁇ m;
  • the composite method is bonding with a conductive polymer adhesive.
  • the conditions are: using a sandwich composite process, PI conductive adhesives are extruded on the aluminum foil respectively. Between the conductive polymer film 200 and the aluminum foil and the conductive polymer film 300, they are bonded by reaction and solidification after rolling and laminating.
  • conductive polymer films 200 and 300 PP is used as the polymer material, and the conductive agents are SP, Ketjen Black and graphene.
  • the mass ratio is 60%: 25%: 10%: 5%; use a screw extruder to mix Refining and granulating, put the particles into the screw extruder to re-melt and then add the pore-forming agent paraffin oil.
  • the mass ratio of the molten material to the pore-forming agent is 100:180.
  • the oil film was stretched 6 times in total after 6-level longitudinal stretching at 155°C, and then transversely stretched once at 165°C, with a stretching ratio of 6 times. Then use dichloromethane to extract and remove the paraffin oil, dry it and draw it twice horizontally into a porous conductive film with a thickness of 4 ⁇ m;
  • the metal foil 100 used is aluminum foil with a thickness of 7 ⁇ m;
  • the conductive polymer films 200 and 300 prepared above are used on both sides of the aluminum foil to cover the entire surface.
  • the composite method is bonded by a conductive polymer adhesive.
  • the conditions are: using a sandwich composite process, the PI conductive adhesives are extruded on The aluminum foil and the conductive polymer film 200, and the aluminum foil and the conductive polymer film 300 are bonded by reaction and solidification after roller lamination.
  • conductive polymer films 200 and 300 Preparation of conductive polymer films 200 and 300: PP is used as the polymer material, and SP, Ketjen Black and graphene are used as paraffin conductive agents.
  • the mass ratio is 60%:25%:10%:5%; a screw extruder is used. Mix and granulate, put the particles into the screw extruder to re-melt, and then add the pore-forming agent paraffin oil.
  • the mass ratio of the molten material to the pore-forming agent is 100:180.
  • the oil film was stretched 6 times in total by 6 levels of longitudinal stretching at 155°C, and then transversely stretched once at 165°C, with a stretching ratio of 6 times. Then use dichloromethane to extract and remove the paraffin oil, dry it and draw it twice horizontally into a porous conductive film with a thickness of 4 ⁇ m;
  • the metal foil 100 used is aluminum foil with a thickness of 7 ⁇ m;
  • the conductive polymer films 200 and 300 prepared above are used on both sides of the aluminum foil to cover the entire surface.
  • the composite method is hot pressing.
  • the conditions are: Plasma activation treatment is performed on both sides of the aluminum foil, and the conductive polymer films 200 and 300 are covered before proceeding. Multi-roller lamination, hot pressing temperature is 165°C.
  • conductive polymer films 200 and 300 Preparation of conductive polymer films 200 and 300: PP is used as the polymer material, and the conductive agents are SP, Ketjen Black and graphene. The mass ratio is 60%: 25%: 10%: 5%; use a screw extruder to mix After refining and granulating, it is melted and cast into a conductive film with a thickness of 0.5 ⁇ m;
  • the metal foil 100 used is aluminum foil with a thickness of 7 ⁇ m;
  • the conductive polymer films 200 and 300 prepared above are used on both sides of the aluminum foil to cover the entire surface.
  • the composite method is hot pressing.
  • the conditions are: Plasma activation treatment is performed on both sides of the aluminum foil, and the conductive polymer films 200 and 300 are covered before proceeding. Multi-roller lamination, hot pressing temperature is 165°C.
  • conductive polymer films 200 and 300 Preparation of conductive polymer films 200 and 300: PP is used as the polymer material, and the conductive agents are SP, Ketjen Black and graphene. The mass ratio is 60%: 25%: 10%: 5%; use a screw extruder to mix After refining and granulating, it is melted and cast into a conductive film with a thickness of 100 ⁇ m;
  • the metal foil 100 used is aluminum foil with a thickness of 15 ⁇ m;
  • the conductive polymer films 200 and 300 prepared as above are used to cover the entire surface of both sides of the aluminum foil.
  • the lamination method is hot pressing lamination. The conditions are: plasma activation treatment is performed on both sides of the aluminum foil, and after covering the conductive polymer films 200 and 300, multiple roller pressing lamination is performed.
  • the hot pressing temperature is 165°C.
  • Aluminum foil with a thickness of 15 ⁇ m.
  • Copper foil with a thickness of 15 ⁇ m.
  • the cathode active material NCM 333 Disperse the cathode active material NCM 333 , conductive carbon black SP and binder PVDF into the solvent NMP in a weight ratio of 97%:1%:2% and mix evenly to obtain a cathode slurry with a solid content of 50wt%;
  • the positive electrode slurry is evenly coated on the positive electrode current collector (the aluminum foil of 15 ⁇ m is set as the comparative example according to the object to be tested, and the metal foil is one of the composite current collectors of aluminum foil in the embodiment). After drying and cold pressing, the positive electrode is obtained. Extreme piece.
  • Negative electrode slurry the solid content of the negative electrode slurry is 30wt%; the negative electrode slurry is evenly coated on the negative electrode current collector (according to the object to be tested, it is set as a 15 ⁇ m copper foil in the comparative example or a composite current collector in which the metal foil is copper foil in the embodiment 1), dried at 85°C, transferred to a vacuum oven at 120°C for drying for 12 hours, and then supercooled, pressed, and cut to obtain negative electrode sheets.
  • the organic solvent is a mixed solution containing ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC), where the volume ratio of EC, EMC and DEC is 20:20:60.
  • EC ethylene carbonate
  • EMC ethyl methyl carbonate
  • DEC diethyl carbonate
  • the concentration of lithium salt is 1mol/L.
  • the composite current collectors of the Examples and Comparative Examples were made into strips with a length of 15 cm and a width of 3 cm.
  • the test method was to use a tensile machine to stretch the strips at a stretching speed of 50 mm/min, and record the maximum force at break.
  • the composite current collectors of the Examples and Comparative Examples were made into corresponding batteries according to the "Application Examples" (the pole piece on the other side is a 12 ⁇ m aluminum foil (positive electrode) or a 9 ⁇ m copper foil (negative electrode)).
  • the test method refers to HPPC test method in the American "FreedomCAR Battery Test Manual”.
  • the composite current collectors of the Examples and Comparative Examples were made into corresponding batteries according to the "Application Examples" (the pole piece on the other side is a 12 ⁇ m aluminum foil (positive electrode) or a 9 ⁇ m copper foil (negative electrode)), and the test method is: A temperature sensing line is arranged in the middle of the large surface of the battery core to monitor temperature changes during the 5C cycle charge and discharge process.
  • the composite current collectors of the Examples and Comparative Examples were made into corresponding batteries according to the "Application Examples" (the pole piece on the other side is a 12 ⁇ m aluminum foil (positive electrode) or a 9 ⁇ m copper foil (negative electrode)).
  • the battery is 1C After 300 cycles of charge and discharge, it was disassembled and the corrosion of the current collector was observed.
  • the composite current collector of the present application has the conductive polymer layer as the outermost layer and has significantly higher breaking tensile force than Comparative Examples 1 to 2. At the same time, the internal resistance of the battery is similar without significant increase. In addition, the composite current collector of the present application also has the effect of reducing metal foil corrosion by arranging the conductive polymer layer in the outermost layer.

Abstract

本申请涉及复合集流体及其制作方法、电极片、二次电池和用电装置。所述复合集流体，其包含金属箔，所述金属箔包括位置相对的第一表面和第二表面，所述第一表面设有第一导电聚合物层，所述第二表面设有第二导电聚合物层，所述第一导电聚合物层和第二导电聚合物层的材料相同或不同，且均包含聚合物材料和导电剂。上述复合集流体有效提升了集流体的拉伸强度，改善了金属箔在锂离子电池的生产过程中断带的问题，同时方便对金属箔进行减薄或采用较薄的金属箔，提高电极片的能量密度。此外，导电聚合物层的存在对电解液能够起到隔离的作用，减少或避免电解液对金属箔的腐蚀。

Description

复合集流体及其制作方法、电极片、二次电池和用电装置 技术领域
本申请涉及锂电池技术领域，尤其涉及一种正极活性材料、二次电池和用电装置。
背景技术
近年来，随着锂离子电池的应用范围越来越广泛，锂离子电池广泛应用于水力、火力、风力和太阳能电站等储能电源系统，以及电动工具、电动自行车、电动摩托车、电动汽车、军事装备、航空航天等多个领域。由于锂离子电池取得了极大的发展，因此对其能量密度、循环性能和安全性能等也提出了更高的要求。
锂离子电池的电极片主要由集流体以及设置于集流体表面的电极活性材料层组成，其中集流体的材质主要为金属箔材，在电极片中起到导流的作用。集流体的厚薄会影响电极片的能量密度，因此会要求其厚度尽可能地薄。但是，由于目前锂离子电池在生产过程中需要经过拉伸、辊压、卷绕等工序，金属箔经减薄处理后存在生产断带的风险，同时制得的锂离子电池在实际应用的过程中，也会存在过流能力不足的问题。
发明内容
本申请是鉴于上述课题而进行的，其目的在于，提供一种复合集流体及其制作方法、电极片、二次电池和用电装置。
为了达到上述目的，本申请的第一方面提供了一种复合集流体，其包含金属箔，所述金属箔包括位置相对的第一表面和第二表面，所述第一表面设有第一导电聚合物层，所述第二表面设有第二导电聚合物层，所述第一导电聚合物层和第二导电聚合物层的材料组成相同或不同，且均包含聚合物材料和导电剂。
本申请的第二方面还提供一种复合集流体的制备方法，包括如下步骤：
将聚合物材料和导电剂混合，所得混合物成膜处理，分别制备第一导电聚合物层和第二导电聚合物层；
将所述第一导电聚合物层复合于金属箔的第一表面；
将所述第二导电聚合物层复合于金属箔的第二表面；
其中，所述第一表面和第二表面位置相对，所述第一导电聚合物层和第二导电聚合物层的材料相同或不同。
本申请的第三方面还提供一种电极片，包括集流体以及设置在所述集流体至少一个表面的电极膜层；所述集流体为第一方面所述的复合集流体或第二方面所述的制备方法制备得到的复合集流体。
本申请的第四方面还提供一种二次电池，包括第三方面所述的电极片。
本申请的第五方面还提供一种用电装置，包括第四方面所述的二次电池。
附图说明
图1是本申请一实施方式的复合集流体的结构示意图；
图2是本申请一实施方式的二次电池的示意图；
图3是图2所示的本申请一实施方式的二次电池的分解图；
图4是本申请一实施方式的电池模块的示意图；
图5是本申请一实施方式的电池包的示意图；
图6是图4所示的本申请一实施方式的电池包的分解图；
图7是本申请一实施方式的二次电池用作电源的用电装置的示意图；
附图标记说明：
1、电池包；2、上箱体；3、下箱体；4、电池模块；5、二次电池；51、壳体；52、电极组件；53、盖板；6、用电装置。
具体实施方式
以下，适当地参照附图详细说明具体公开了本申请的复合集流体及其制作方法、电极片、二次电池和用电装置的实施方式。但是会有省略不必要的详细说明的情况。例如，有省略对已众所周知的事项的详细说明、实际相同结构的重复说明的情况。这是为了避免以下的说明不必要地变得冗长，便于本领域技术人员的理解。此外，附图及以下说明是为了本领域技术人员充分理解本申请而提供的，并不旨在限定权利要求书所记载的主题。
本申请所公开的“范围”以下限和上限的形式来限定，给定范围是通过选定一个下限和一个上限进行限定的，选定的下限和上限限定了特别范围的边界。这种方式进行限定的范围可以是包括端值或不包括端值的，并且可以进行任意地组合，即任何下限 可以与任何上限组合形成一个范围。例如，如果针对特定参数列出了60-120和80-110的范围，理解为60-110和80-120的范围也是预料到的。此外，如果列出的最小范围值1和2，和如果列出了最大范围值3，4和5，则下面的范围可全部预料到：1-3、1-4、1-5、2-3、2-4和2-5。在本申请中，除非有其他说明，数值范围“a-b”表示a到b之间的任意实数组合的缩略表示，其中a和b都是实数。例如数值范围“0-5”表示本文中已经全部列出了“0-5”之间的全部实数，“0-5”只是这些数值组合的缩略表示。另外，当表述某个参数为≥2的整数，则相当于公开了该参数为例如整数2、3、4、5、6、7、8、9、10、11、12等。
如果没有特别的说明，本申请的所有实施方式以及可选实施方式可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有技术特征以及可选技术特征可以相互组合形成新的技术方案。
如果没有特别的说明，本申请的所有步骤可以顺序进行，也可以随机进行，优选是顺序进行的。例如，所述方法包括步骤(a)和(b)，表示所述方法可包括顺序进行的步骤(a)和(b)，也可以包括顺序进行的步骤(b)和(a)。例如，所述提到所述方法还可包括步骤(c)，表示步骤(c)可以任意顺序加入到所述方法，例如，所述方法可以包括步骤(a)、(b)和(c)，也可包括步骤(a)、(c)和(b)，也可以包括步骤(c)、(a)和(b)等。
如果没有特别的说明，本申请所提到的“包括”和“包含”表示开放式，也可以是封闭式。例如，所述“包括”和“包含”可以表示还可以包括或包含没有列出的其他组分，也可以仅包括或包含列出的组分。
如果没有特别的说明，在本申请中，术语“或”是包括性的。举例来说，短语“A或B”表示“A，B，或A和B两者”。更具体地，以下任一条件均满足条件“A或B”：A为真(或存在)并且B为假(或不存在)；A为假(或不存在)而B为真(或存在)；或A和B都为真(或存在)。
目前电池高能量密度需求下集流体轻薄化是主要趋势，通过降低厚度(减薄处理)方式金属箔材在生产过程中容易出现断带以及应用中过流能力不足的风险。
基于此，本申请提供一种复合集流体，如图1所示，其包含金属箔100，金属箔100包括位置相对的第一表面和第二表面，第一表面设有第一导电聚合物层200，第二 表面设有第二导电聚合物层300，第一导电聚合物层200和第二导电聚合物层300的材料组成相同或不同，且均包含聚合物材料和导电剂。
上述复合集流体通过在金属箔的两个表面分别设置导电聚合物层，导电聚合物层的存在有效提升了集流体的拉伸强度，改善了金属箔在锂离子电池的生产过程中断带的问题，同时方便对金属箔进行减薄或采用较薄的金属箔，提高电极片的能量密度。此外，导电聚合物层的存在对电解液能够起到隔离的作用，减少或避免电解液对金属箔的腐蚀。
另外值得说明的是，在本领域的传统认知中，为了保证集流体的导流作用，即使将金属箔与其它材料层进行复合，也需要保证金属箔位于复合集流体的最外层。而本申请的上述复合集流体打破了这一认知，尝试将导电聚合物层设置于最外层，并发现在改善断带问题的同时，能够保持集流体的导流作用，对锂离子电池的电性能无负面影响。
进一步地，如图1所示，第一导电聚合物层200覆盖整个第一表面。
进一步地，如图1所示，第二导电聚合物层300覆盖整个第二表面。
进一步地，第一导电聚合物层200、第二导电聚合物层300设置于整个复合集流体的最外层。
在一些实施方式中，第一导电聚合物层200的厚度为0.5μm～100μm。在该厚度之下，既能够提升金属箔的拉伸性能，又能够保证电极片的能量密度。具体地，第一导电聚合物层200的厚度包括但不限于：0.5μm、0.7μm、1μm、2μm、3μm、4μm、5μm、6μm、7μm、8μm、9μm、10μm、20μm、50μm、80μm、90μm、95μm、100μm。
在一些实施方式中，第一导电聚合物层200的材料中，聚合物材料包括热塑性聚合物。进一步地，所述热塑性聚合物为耐电解液聚合物。不作限制地，所述热塑性聚合物包括PP、PE、PI、PAI、PVDF、SBR、NBR和PTFE中的一种或多种。
在一些实施方式中，第一导电聚合物层200的材料中，导电剂包括SP、科琴黑、CNT和石墨烯中的一种或多种。
在一些实施方式中，第一导电聚合物层200的材料中，聚合物材料与导电剂的质量比为(0.05～10):1。具体地，聚合物材料与导电剂的质量比包括但不限于：0.05:1、0.1:1、0.5:1、0.8:1、1:1、1.1:1、1.2:1、1.3:1、1.4:1、1.5:1、1.6:1、1.7:1、2:1、3:1、5:1、7:1、10:1。
在一些实施方式中，第二导电聚合物层300的厚度为0.5μm～100μm。在该厚度之下，既能够提升金属箔的拉伸性能，又能够保证电极片的能量密度。具体地，第一导电聚合物层200的厚度包括但不限于：0.5μm、0.7μm、1μm、2μm、3μm、4μm、5μm、6μm、7μm、8μm、9μm、10μm、20μm、50μm、80μm、90μm、95μm、100μm。
在一些实施方式中，第二导电聚合物层300的材料中，聚合物材料包括热塑性聚合物。进一步地，所述热塑性聚合物为耐电解液聚合物。不作限制地，所述热塑性聚合物包括PP、PE、PI、PAI、PVDF、SBR、NBR和PTFE中的一种或多种。
在一些实施方式中，第二导电聚合物层300的材料中，导电剂包括SP、科琴黑、CNT和石墨烯中的一种或多种。
在一些实施方式中，第二导电聚合物层300的材料中，聚合物材料与导电剂的质量比为(0.05～10):1。具体地，聚合物材料与导电剂的质量比包括但不限于：0.05:1、0.1:1、0.5:1、0.8:1、1:1、1.1:1、1.2:1、1.3:1、1.4:1、1.5:1、1.6:1、1.7:1、2:1、3:1、5:1、7:1、10:1。
可以理解地，第一导电聚合物层200与第二导电聚合物层300的材料相同或不同。
可以理解地，第一导电聚合物层200与第二导电聚合物层300的厚度相同或不同。
在一些实施方式中，金属箔100的厚度为1μm～50μm。在该厚度之下配合第一导电聚合物层200与第二导电聚合物层300，既能够进一步改善金属箔的断带问题，又能够保证电极片的能量密度。具体地，金属箔100的厚度包括但不限于：1μm、2μm、3μm、4μm、5μm、6μm、7μm、8μm、9μm、1μm、10μm、20μm、30μm、50μm。
在一些实施方式中，第一导电聚合物层200设有若干个孔。进一步地，所述孔的孔径为0.1μm～5μm。通过孔的设置，能够使后续制备的电极膜层与第一导电聚合物层200之间紧密结合，减小电池内阻。
在一些实施方式中，第二导电聚合物层300设有若干个孔。进一步地，所述孔的孔径为0.1μm～5μm。通过孔的设置，能够使后续制备的电极膜层与第二导电聚合物层300之间紧密结合，减小电池内阻。
在一些实施方式中，所述金属箔为铜箔，所述复合集流体的断裂拉伸力≥200N；所述金属箔为铝箔，所述复合集流体的断裂拉伸力≥80N。
本申请还提供一种复合集流体的制备方法，包括如下步骤：
(a)将聚合物材料和导电剂混合，所得混合物成膜处理，分别制备第一导电聚合 物层和第二导电聚合物层；
(b)将所述第一导电聚合物层复合于金属箔的第一表面；
(c)将所述第二导电聚合物层复合于金属箔的第二表面；
其中，所述第一表面和第二表面位置相对，所述第一导电聚合物层和第二导电聚合物层的材料相同或不同。
不作限制地，步骤(a)中，混合的方式为熔融混炼，成膜处理的方式为将所得混合物熔融后成膜，成膜的方式可举例如流延、吹膜等。其中熔融混炼的设备可以采用螺杆挤出机。
在一些实施方式中，步骤(b)和(c)中，所述复合的方法分别独立地选自如下方法中的一种：
(1)热压复合；
(2)通过导电聚合物粘接剂粘合；可选地，所述导电聚合物粘接剂包括丙烯酸酯改性的导电胶、环氧改性的导电胶、PI导电胶及PI改性的导电胶中的一种或多种。
可以理解地，方法(1)和(2)可以依据聚合物材料的种类或已有的生产设备进行适应性选择，均能够实现复合的目的。其中相比较方法(2)引入了导电聚合物粘接剂相比较，方法(1)直接热压复合更为便捷和经济，能量密度也较高。
在一些实施方式中，制备得到所述第一导电聚合物层和第二导电聚合物层后，还包括对所述第一导电聚合物层和第二导电聚合物层进行成孔处理的步骤。不作限制地，所述成孔处理的方法可举例如湿法成孔。湿法成孔是使用造孔剂与第一导电聚合物层或第二导电聚合物层的物料在高温下混合成为均相溶液，然后降低温度使两者相分离后将造孔剂萃取去除，从而形成孔。不作限制地，造孔剂可举例如石蜡油。
在一些实施方式中，造孔剂与第一导电聚合物层或第二导电聚合物层的物料的质量比为100:(150～250)。
本申请还提供一种电极片，包括集流体以及设置在所述集流体至少一个表面的电极膜层；所述集流体为如上所述的复合集流体如上所述的制备方法制备得到的复合集流体。不作限制地，所述电极片为正极极片或负极极片，相应地，所述集流体为正极集流体或负极集流体。
以下适当参照附图对本申请的电极片、二次电池、电池模块、电池包和用电装置进行说明。
本申请的一个实施方式中，提供一种二次电池。
通常情况下，二次电池包括正极极片、负极极片、电解质和隔离膜。在电池充放电过程中，活性离子在正极极片和负极极片之间往返嵌入和脱出。电解质在正极极片和负极极片之间起到传导离子的作用。隔离膜设置在正极极片和负极极片之间，主要起到防止正负极短路的作用，同时可以使离子通过。
正极极片
正极极片包括正极集流体以及设置在正极集流体至少一个表面的正极膜层，所述正极膜层包括正极活性材料。
作为示例，正极集流体具有在其自身厚度方向相对的两个表面，正极膜层设置在正极集流体相对的两个表面的其中任意一者或两者上。
在一些实施方式中，所述正极集流体采用的金属箔的金属材料包括但不限于铝、铝合金、镍、镍合金、钛、钛合金、银及银合金等。
在一些实施方式中，正极活性材料可包含本领域公知的用于电池的正极活性材料。作为示例，正极活性材料可包括以下材料中的至少一种：橄榄石结构的含锂磷酸盐、锂过渡金属氧化物及其各自的改性化合物。但本申请并不限定于这些材料，还可以使用其他可被用作电池正极活性材料的传统材料。这些正极活性材料可以仅单独使用一种，也可以将两种以上组合使用。其中，锂过渡金属氧化物的示例可包括但不限于锂钴氧化物(如LiCoO 2)、锂镍氧化物(如LiNiO 2)、锂锰氧化物(如LiMnO 2、LiMn 2O 4)、锂镍钴氧化物、锂锰钴氧化物、锂镍锰氧化物、锂镍钴锰氧化物(如LiNi 1/3Co 1/3Mn 1/3O 2(也可以简称为NCM 333)、LiNi 0.5Co 0.2Mn 0.3O 2(也可以简称为NCM 523)、LiNi 0.5Co 0.25Mn 0.25O 2(也可以简称为NCM 211)、LiNi 0.6Co 0.2Mn 0.2O 2(也可以简称为NCM 622)、LiNi 0.8Co 0.1Mn 0.1O 2(也可以简称为NCM 811)、锂镍钴铝氧化物(如LiNi 0.85Co 0.15Al 0.05O 2)及其改性化合物等中的至少一种。橄榄石结构的含锂磷酸盐的示例可包括但不限于磷酸铁锂(如LiFePO 4(也可以简称为LFP))、磷酸铁锂与碳的复合材料、磷酸锰锂(如LiMnPO 4)、磷酸锰锂与碳的复合材料、磷酸锰铁锂、磷酸锰铁锂与碳的复合材料中的至少一种。所述正极活性材料在正极膜层中的重量比为80-100重量％，基于正极膜层的总重量计。
在一些实施方式中，正极膜层还可选地包括粘结剂。作为示例，所述粘结剂可以包括聚偏氟乙烯(PVDF)、聚四氟乙烯(PTFE)、偏氟乙烯-四氟乙烯-丙烯三元共聚物、 偏氟乙烯-六氟丙烯-四氟乙烯三元共聚物、四氟乙烯-六氟丙烯共聚物及含氟丙烯酸酯树脂中的至少一种。所述粘结剂在正极膜层中的重量比为0-20重量％，基于正极膜层的总重量计。
在一些实施方式中，正极膜层还可选地包括导电剂。作为示例，所述导电剂可以包括超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。所述导电剂在正极膜层中的重量比为0-20重量％，基于正极膜层的总重量计。
在一些实施方式中，可以通过以下方式制备正极极片：将上述用于制备正极极片的组分，例如正极活性材料、导电剂、粘结剂和任意其他的组分分散于溶剂(例如N-甲基吡咯烷酮)中，形成正极浆料，其中所述正极浆料固含量为40-80wt％，室温下的粘度调整到5000-25000mPa·s，将正极浆料涂覆在正极集流体的表面，烘干后经过冷轧机冷压后形成正极极片；正极粉末涂布单位面密度为150-350mg/m 2，正极极片压实密度为3.0-3.6g/cm 3，可选为3.3-3.5g/cm 3。所述压实密度的计算公式为
压实密度＝涂布面密度/(挤压后极片厚度-集流体厚度)。
负极极片
负极极片包括负极集流体以及设置在负极集流体至少一个表面上的负极膜层，所述负极膜层包括负极活性材料。
作为示例，负极集流体具有在其自身厚度方向相对的两个表面，负极膜层设置在负极集流体相对的两个表面中的任意一者或两者上。
在一些实施方式中，所述负极集流体采用的金属箔的金属材料包括但不限于铜、铜合金、镍、镍合金、钛、钛合金、银及银合金等。
在一些实施方式中，负极活性材料可采用本领域公知的用于电池的负极活性材料。作为示例，负极活性材料可包括以下材料中的至少一种：人造石墨、天然石墨、软炭、硬炭、硅基材料、锡基材料和钛酸锂等。所述硅基材料可选自单质硅、硅氧化合物、硅碳复合物、硅氮复合物以及硅合金中的至少一种。所述锡基材料可选自单质锡、锡氧化合物以及锡合金中的至少一种。但本申请并不限定于这些材料，还可以使用其他可被用作电池负极活性材料的传统材料。这些负极活性材料可以仅单独使用一种，也可以将两种以上组合使用。所述负极活性材料在负极膜层中的重量比为70-100重量％，基于负极膜层的总重量计。
在一些实施方式中，负极膜层还可选地包括粘结剂。所述粘结剂可选自丁苯橡胶 (SBR)、聚丙烯酸(PAA)、聚丙烯酸钠(PAAS)、聚丙烯酰胺(PAM)、聚乙烯醇(PVA)、海藻酸钠(SA)、聚甲基丙烯酸(PMAA)及羧甲基壳聚糖(CMCS)中的至少一种。所述粘结剂在负极膜层中的重量比为0-30重量％，基于负极膜层的总重量计。
在一些实施方式中，负极膜层还可选地包括导电剂。导电剂可选自超导碳、乙炔黑、炭黑、科琴黑、碳点、碳纳米管、石墨烯及碳纳米纤维中的至少一种。所述导电剂在负极膜层中的重量比为0-20重量％，基于负极膜层的总重量计。
在一些实施方式中，负极膜层还可选地包括其他助剂，例如增稠剂(如羧甲基纤维素钠(CMC-Na))等。所述其他助剂在负极膜层中的重量比为0-15重量％，基于负极膜层的总重量计。
在一些实施方式中，可以通过以下方式制备负极极片：将上述用于制备负极极片的组分，例如负极活性材料、导电剂、粘结剂和任意其他组分分散于溶剂(例如去离子水)中，形成负极浆料，其中所述负极浆料固含量为30-70wt％，室温下的粘度调整到2000-10000mPa·s；将所得到的负极浆料涂覆在负极集流体上，经过干燥工序，冷压例如对辊，得到负极极片。负极粉末涂布单位面密度为75-220mg/m 2，负极极片压实密度1.2-2.0g/m 3。
电解质
电解质在正极极片和负极极片之间起到传导离子的作用。本申请对电解质的种类没有具体的限制，可根据需求进行选择。例如，电解质可以是液态的、凝胶态的或全固态的。
在一些实施方式中，所述电解质采用电解液。所述电解液包括电解质盐和溶剂。
在一些实施方式中，电解质盐可选自六氟磷酸锂(LiPF 6)、四氟硼酸锂(LiBF 4)、高氯酸锂(LiClO 4)、六氟砷酸锂(LiAsF 6)、双氟磺酰亚胺锂(LiFSI)、双三氟甲磺酰亚胺锂(LiTFSI)、三氟甲磺酸锂(LiTFS)、二氟草酸硼酸锂(LiDFOB)、二草酸硼酸锂(LiBOB)、二氟磷酸锂(LiPO 2F 2)、二氟二草酸磷酸锂(LiDFOP)及四氟草酸磷酸锂(LiTFOP)中的一种或几种。所述电解质盐的浓度通常为0.5-5mol/L。
在一些实施方式中，溶剂可选自氟代碳酸乙烯酯(FEC)、碳酸亚乙酯(EC)、碳酸亚丙基酯(PC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)、碳酸二甲酯(DMC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸亚丁酯(BC)、 甲酸甲酯(MF)、乙酸甲酯(MA)、乙酸乙酯(EA)、乙酸丙酯(PA)、丙酸甲酯(MP)、丙酸乙酯(EP)、丙酸丙酯(PP)、丁酸甲酯(MB)、丁酸乙酯(EB)、1,4-丁内酯(GBL)、环丁砜(SF)、二甲砜(MSM)、甲乙砜(EMS)及二乙砜(ESE)中的一种或几种。
在一些实施方式中，所述电解液还可选地包括添加剂。例如添加剂可以包括负极成膜添加剂、正极成膜添加剂，还可以包括能够改善电池某些性能的添加剂，例如改善电池过充性能的添加剂、改善电池高温或低温性能的添加剂等。
隔离膜
在一些实施方式中，二次电池中还包括隔离膜。本申请对隔离膜的种类没有特别的限制，可以选用任意公知的具有良好的化学稳定性和机械稳定性的多孔结构隔离膜。
在一些实施方式中，隔离膜的材质可选自玻璃纤维、无纺布、聚乙烯、聚丙烯及聚偏二氟乙烯中的至少一种。隔离膜可以是单层薄膜，也可以是多层复合薄膜，没有特别限制。在隔离膜为多层复合薄膜时，各层的材料可以相同或不同，没有特别限制。
在一些实施方式中，所述隔离膜的厚度为6-40μm，可选为12-20μm。
在一些实施方式中，正极极片、负极极片和隔离膜可通过卷绕工艺或叠片工艺制成电极组件。
在一些实施方式中，二次电池可包括外包装。该外包装可用于封装上述电极组件及电解质。
在一些实施方式中，二次电池的外包装可以是硬壳，例如硬塑料壳、铝壳、钢壳等。二次电池的外包装也可以是软包，例如袋式软包。软包的材质可以是塑料，作为塑料，可列举出聚丙烯、聚对苯二甲酸丁二醇酯以及聚丁二酸丁二醇酯等。
本申请对二次电池的形状没有特别的限制，其可以是圆柱形、方形或其他任意的形状。例如，图2是作为一个示例的方形结构的二次电池5。
在一些实施方式中，参照图3，外包装可包括壳体51和盖板53。其中，壳体51可包括底板和连接于底板上的侧板，底板和侧板围合形成容纳腔。壳体51具有与容纳腔连通的开口，盖板53能够盖设于所述开口，以封闭所述容纳腔。正极极片、负极极片和隔离膜可经卷绕工艺或叠片工艺形成电极组件52。电极组件52封装于所述容纳腔内。电解液浸润于电极组件52中。二次电池5所含电极组件52的数量可以为一个或多个，本领域技术人员可根据具体实际需求进行选择。
在一些实施方式中，二次电池可以组装成电池模块，电池模块所含二次电池的数量可以为一个或多个，具体数量本领域技术人员可根据电池模块的应用和容量进行选择。
图4是作为一个示例的电池模块4。参照图4，在电池模块4中，多个二次电池5可以是沿电池模块4的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个二次电池5进行固定。
可选地，电池模块4还可以包括具有容纳空间的外壳，多个二次电池5容纳于该容纳空间。
在一些实施方式中，上述电池模块还可以组装成电池包，电池包所含电池模块的数量可以为一个或多个，具体数量本领域技术人员可根据电池包的应用和容量进行选择。
图5和图6是作为一个示例的电池包1。参照图5和图6，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模块4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。
另外，本申请还提供一种用电装置，所述用电装置包括本申请提供的二次电池、电池模块、或电池包中的至少一种。所述二次电池、电池模块、或电池包可以用作所述用电装置的电源，也可以用作所述用电装置的能量存储单元。所述用电装置可以包括移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能系统等，但不限于此。
作为所述用电装置，可以根据其使用需求来选择二次电池、电池模块或电池包。
图7是作为一个示例的用电装置。该用电装置为纯电动车、混合动力电动车、或插电式混合动力电动车等。为了满足该用电装置对二次电池的高功率和高能量密度的需求，可以采用电池包或电池模块。
作为另一个示例的装置可以是手机、平板电脑、笔记本电脑等。该装置通常要求轻薄化，可以采用二次电池作为电源。
实施例
为了使本申请所解决的技术问题、技术方案及有益效果更加清楚，以下将结合实 施例和附图对本申请进行进一步详细说明。显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。以下对至少一个示例性实施例的描述实际上仅仅是说明性的，决不作为对本申请及其应用的任何限制。基于本申请中的实施例，本领域普通技术人员在没有付出创造性劳动前提下所获得的所有其他实施例都属于本申请保护的范围。
实施例中未注明具体技术或条件的，按照本领域内的文献所描述的技术或条件或者按照产品说明书进行。所用试剂或仪器未注明生产厂商者，均为可以通过市购获得的常规产品。
一、制备实施例
实施例1-1
导电聚合物薄膜200和300的制备：聚合物材料使用PP，导电剂为SP、科琴黑和石墨烯，其质量比为60％：25％：10％：5％；使用螺杆挤出机混炼造粒后熔融，流延成厚度4μm的导电薄膜；
所用金属箔100为铝箔，厚度7μm；
于铝箔的两面均使用上述制备的导电聚合物薄膜200和300覆盖整个表面，复合的方式为热压复合，条件为：将铝箔的两面进行Plasma活化处理，覆盖导电聚合物薄膜200和300后进行多重辊压复合，热压温度为165℃。
实施例1-2
导电聚合物薄膜200的制备：聚合物材料使用PE，导电剂为SP、科琴黑和石墨烯，其质量比为55％：28％：11％：6％；使用螺杆挤出机混炼造粒后熔融，吹膜成厚度5μm的导电薄膜；
所用金属箔100为铜箔，厚度5μm；
导电聚合物薄膜300的制备：聚合物材料使用PP，导电剂为SP、科琴黑和石墨烯，其质量比为60％：25％：10％：5％；使用螺杆挤出机混炼造粒后熔融，流延成厚度5μm的导电薄膜；
于铜箔的两面使用上述制备的导电聚合物薄膜200和300覆盖整个表面，复合的方式为热压复合，条件为：将铜箔的两面进行Plasma活化处理，分别覆盖导电聚合物薄膜200和300多重辊压复合，顺序为先复合导电聚合物薄膜200，热压温度为120℃， 后复合导电聚合物薄膜300，热压温度为165℃。
实施例1-3
导电聚合物薄膜200的制备：聚合物材料使用PE，导电剂为SP、CNT和石墨烯，其质量比为55％：28％：11％：6％；使用螺杆挤出机混炼造粒后熔融，吹膜成厚度6μm的导电薄膜；
所用金属箔100为铝箔，厚度5μm；
导电聚合物薄膜300的制备：聚合物材料使用PP，导电剂为SP、CNT和石墨烯，其质量比为60％：25％：10％：5％；使用螺杆挤出机混炼造粒后熔融，流延成厚度4μm的导电薄膜；
于铝箔的两面使用上述制备的导电聚合物薄膜200和300覆盖整个表面，复合的方式为热压复合，条件为：将铝箔的两面进行Plasma活化处理，分别覆盖导电聚合物薄膜200和300后多重辊压复合，顺序为先复合导电聚合物薄膜200，热压温度为120℃，后复合导电聚合物薄膜300，热压温度为165℃。
实施例1-4
导电聚合物薄膜200的制备：聚合物材料使用PE，导电剂为SP、科琴黑和石墨烯，其质量比为55％：28％：11％：6％；使用螺杆挤出机混炼造粒后熔融，吹膜成厚度5μm的导电薄膜；
所用金属箔100为铜箔，厚度6μm；
导电聚合物薄膜300的制备：聚合物材料使用PP，导电剂为SP、科琴黑和石墨烯，其质量比为60％：25％：10％：5％；使用螺杆挤出机混炼造粒后熔融，流延成厚度4μm的导电薄膜；
于铜箔的两面使用上述制备的导电聚合物薄膜200和300覆盖整个表面，复合的方式为热压复合，条件为：将铜箔的两面进行Plasma活化处理，分别覆盖导电聚合物薄膜200和300后多重辊压复合，顺序为先复合导电聚合物薄膜200，热压温度为120℃，后复合导电聚合物薄膜300，热压温度为165℃。
实施例2-1
导电聚合物薄膜200和300的制备：聚合物材料使用PP，导电剂为SP、科琴黑和 石墨烯，其质量比为60％：25％：10％：5％；使用螺杆挤出机混炼造粒后熔融，流延成厚度4μm的导电薄膜；
所用金属箔100为铝箔，厚度7μm；
于铝箔的两面均使用上述制备的导电聚合物薄膜200和300覆盖整个表面，复合的方式为通过导电聚合物粘接剂粘合，条件为：采用三明治复合工艺，将PI导电胶分别挤出在铝箔与导电聚合物薄膜200、铝箔与导电聚合物薄膜300的中间，经过辊压复合后反应固化实现粘接。
实施例2-2
导电聚合物薄膜200的制备：聚合物材料使用PE，导电剂为SP、CNT和石墨烯，其质量比为55％：28％：11％：6％；使用螺杆挤出机混炼造粒后熔融，流延成厚度6μm的导电薄膜；
所用金属箔100为铝箔，厚度5μm；
导电聚合物薄膜300的制备：聚合物材料使用PP，导电剂为SP、CNT和石墨烯，其质量比为60％：25％：10％：5％；使用螺杆挤出机混炼造粒后熔融，流延成厚度4μm的导电薄膜；
于铝箔的两面使用上述制备的导电聚合物薄膜200和300覆盖整个表面，复合的方式为通过导电聚合物粘接剂粘合，条件为：采用三明治复合工艺，将PI导电胶分别挤出在铝箔与导电聚合物薄膜200、铝箔与导电聚合物薄膜300的中间，经过辊压复合后反应固化实现粘接。
实施例3-1
导电聚合物薄膜200和300的制备：聚合物材料使用PP，导电剂为SP、科琴黑和石墨烯，其质量比为60％：25％：10％：5％；使用螺杆挤出机混炼造粒，将粒子置入螺杆挤出机重新熔融后加入造孔剂石蜡油，熔融物料与造孔剂的质量比为100：180，经螺杆挤出后迅速冷却至55℃形成油膜，将油膜在155℃经6级纵向拉伸后总拉伸6倍，然后在165℃条件下进行一次横向拉伸，拉伸比率为6倍。然后使用二氯甲烷将石蜡油萃取去除，干燥后二次横拉成厚度4μm的多孔导电薄膜；
所用金属箔100为铝箔，厚度7μm；
于铝箔的两面均使用上述制备的导电聚合物薄膜200和300覆盖整个表面，复合 的方式为通过导电聚合物粘接剂粘合，条件为：采用三明治复合工艺，将PI导电胶分别挤出在铝箔与导电聚合物薄膜200、铝箔与导电聚合物薄膜300的中间，经过辊压复合后反应固化实现粘接。
实施例4-1
导电聚合物薄膜200和300的制备：聚合物材料使用PP，石蜡导电剂为SP、科琴黑和石墨烯，其质量比为60％：25％：10％：5％；使用螺杆挤出机混炼造粒，将粒子置入螺杆挤出机重新熔融后加入造孔剂石蜡油，熔融物料与造孔剂的质量比为100：180，经螺杆挤出后迅速冷却至55℃形成油膜，将油膜在155℃经6级纵向拉伸后总拉伸6倍，然后在165℃条件下进行一次横向拉伸，拉伸比率为6倍。然后使用二氯甲烷将石蜡油萃取去除，干燥后二次横拉成厚度4μm的多孔导电薄膜；
所用金属箔100为铝箔，厚度7μm；
于铝箔的两面均使用上述制备的导电聚合物薄膜200和300覆盖整个表面，复合的方式为热压复合，条件为：将铝箔的两面进行Plasma活化处理，覆盖导电聚合物薄膜200和300后进行多重辊压复合，热压温度为165℃。
实施例5-1
导电聚合物薄膜200和300的制备：聚合物材料使用PP，导电剂为SP、科琴黑和石墨烯，其质量比为60％：25％：10％：5％；使用螺杆挤出机混炼造粒后熔融，流延成厚度0.5μm的导电薄膜；
所用金属箔100为铝箔，厚度7μm；
于铝箔的两面均使用上述制备的导电聚合物薄膜200和300覆盖整个表面，复合的方式为热压复合，条件为：将铝箔的两面进行Plasma活化处理，覆盖导电聚合物薄膜200和300后进行多重辊压复合，热压温度为165℃。
实施例5-2
导电聚合物薄膜200和300的制备：聚合物材料使用PP，导电剂为SP、科琴黑和石墨烯，其质量比为60％：25％：10％：5％；使用螺杆挤出机混炼造粒后熔融，流延成厚度100μm的导电薄膜；
所用金属箔100为铝箔，厚度15μm；
于铝箔的两面均使用上述制备的导电聚合物薄膜200和300覆盖整个表面，复合的方式为热压复合，条件为：将铝箔的两面进行Plasma活化处理，覆盖导电聚合物薄膜200和300后进行多重辊压复合，热压温度为165℃。
对比例1
厚度为15μm的铝箔。
对比例2
厚度为15μm的铜箔。
二、应用实施例
1)正极极片的制备
将正极活性材料NCM 333、导电炭黑SP及粘结剂PVDF按照重量比97％:1％:2％分散至溶剂NMP中进行混合均匀，得到正极浆料，正极浆料固体含量为50wt％；将正极浆料均匀涂布于正极集流体(依据待测对象设置为对比例15μm的铝箔、实施例中金属箔为铝箔的复合集流体之一)上，经烘干、冷压后，得到正极极片。
2)负极极片的制备
将负极活性材料石墨、增稠剂CMC、粘接剂丁苯橡胶、导电剂SP，按照质量比90％:1％:2％:7％进行混合，加入去离子水，在真空搅拌机作用下获得负极浆料，负极浆料固体含量为30wt％；将负极浆料均匀涂覆在负极集流体(依据待测对象设置为对比例15μm的铜箔或实施例中金属箔为铜箔的复合集流体之一)上，在85℃烘干后转移至120℃真空烘箱干燥12h，然后过冷压、分切得到负极片。
3)隔离膜
选用12μm厚的聚丙烯隔离膜。
4)电解液的制备
有机溶剂为含有碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)和碳酸二乙酯(DEC)的混液，其中，EC、EMC和DEC的体积比为20:20:60。在含水量<0.1ppm的氩气气氛手套箱中，将充分干燥的锂盐LiPF6溶解于有机溶剂中，混合均匀，获得电解液。其中，锂盐的浓度为1mol/L。
5)电池的制备
将正极片、隔离膜、负极片按顺序叠好，使隔离膜处于正、负极片之间起到隔离的作用，再卷绕成方形的裸电芯后，装入电池壳体中，然后经静置、化成等工序后，得到锂离子电池。
三、性能测试
1.复合集流体的断裂拉伸力及断裂伸长率测试
将实施例和对比例的复合集流体制成长15cm、宽3cm的条带，测试方法：使用拉力机进行拉伸，拉伸速度50mm/min，记录断裂时最大力。
2.电池性能
2.1内阻
将实施例和对比例的复合集流体分别按照“应用实施例”制成相应的电池(相应另一侧的极片为12μm的铝箔(正极)或9μm的铜箔(负极))，测试方法参考美国《FreedomCAR电池测试手册》中的HPPC测试方法。
2.2 5C循环充放电过程中电极表面最高温度
将实施例和对比例的复合集流体分别按照“应用实施例”制成相应的电池(相应另一侧的极片为12μm的铝箔(正极)或9μm的铜箔(负极))，测试方法：电芯大面中间布置感温线，监测5C循环充放电过程中温度变化。
2.3集流体腐蚀情况
将实施例和对比例的复合集流体分别按照“应用实施例”制成相应的电池(相应另一侧的极片为12μm的铝箔(正极)或9μm的铜箔(负极))，电池以1C充放电300循环后拆解，观察集流体腐蚀情况。
各项性能参数结果见下表1。
表1
Figure PCTCN2022120745-appb-000001
Figure PCTCN2022120745-appb-000002
由表1可知，本申请的复合集流体将导电聚合物层设置于最外层，较对比例1～2具有明显更高的断裂拉伸力，同时电池内阻相当，无明显增加。此外，本申请的复合集流体通过将导电聚合物层设置于最外层还具有减少金属箔腐蚀的作用。
需要说明的是，本申请不限定于上述实施方式。上述实施方式仅为示例，在本申请的技术方案范围内具有与技术思想实质相同的构成、发挥相同作用效果的实施方式均包含在本申请的技术范围内。此外，在不脱离本申请主旨的范围内，对实施方式施加本领域技术人员能够想到的各种变形、将实施方式中的一部分构成要素加以组合而构筑的其它方式也包含在本申请的范围内。

Claims (15)

  1. 一种复合集流体，其包含金属箔，所述金属箔包括位置相对的第一表面和第二表面，所述第一表面设有第一导电聚合物层，所述第二表面设有第二导电聚合物层，所述第一导电聚合物层和第二导电聚合物层的材料组成相同或不同，且均包含聚合物材料和导电剂。
  2. 根据权利要求1所述的复合集流体，其特征在于，所述第一导电聚合物层覆盖整个所述第一表面，所述第二导电聚合物层覆盖整个所述第二表面。
  3. 根据权利要求1或2所述的复合集流体，其特征在于，所述第一导电聚合物层具有如下所示特征中的一个或多个：
    (1)所述第一导电聚合物层的厚度为0.5μm～100μm，可选地，所述第一导电聚合物层的厚度为0.5μm～10μm；
    (2)所述第一导电聚合物层的材料中，聚合物材料包括热塑性聚合物；可选地，所述热塑性聚合物包括PP、PE、PI、PAI、PVDF、SBR、NBR和PTFE中的一种或多种；
    (3)所述第一导电聚合物层的材料中，导电剂包括SP、科琴黑、CNT和石墨烯中的一种或多种。
  4. 根据权利要求1～3任一项所述的复合集流体，其特征在于，所述第一导电聚合物层的材料中，聚合物材料与导电剂的质量比为(0.05～10):1；可选地，聚合物材料与导电剂的质量比为(1～3):1。
  5. 根据权利要求1～4任一项所述的复合集流体，其特征在于，所述第二导电聚合物层具有如下所示特征中的一个或多个：
    (1)所述第二导电聚合物层的厚度为0.5μm～100μm，可选地，所述第一导电聚合物层的厚度为0.5μm～10μm；
    (2)所述第二导电聚合物层的材料中，聚合物材料包括热塑性聚合物；可选地，所述热塑性聚合物包括PP、PE、PI、PAI、PVDF、SBR、NBR和PTFE中的一种或多种；
    (3)所述第二导电聚合物层的材料中，导电剂包括SP、科琴黑、CNT和石墨烯中的一种或多种。
  6. 根据权利要求1～5任一项所述的复合集流体，其特征在于，所述第二导电聚合物 层的材料中，聚合物材料与导电剂的质量比为(0.05～10):1；可选地，聚合物材料与导电剂的质量比为(1～3):1。
  7. 根据权利要求1～6任一项所述的复合集流体，其特征在于，所述金属箔的厚度为1μm～50μm。
  8. 根据权利要求1～7任一项所述的复合集流体，其特征在于，所述第一导电聚合物层和第二导电聚合物层各自独立地设有若干个孔；可选地，所述孔的孔径为0.1μm～5μm。
  9. 根据权利要求1～8任一项所述的复合集流体，其特征在于，所述复合集流体具有如下所示特征之一：
    (1)所述金属箔为铜箔，所述复合集流体的断裂拉伸力≥200N；
    (2)所述金属箔为铝箔，所述复合集流体的断裂拉伸力≥80N。
  10. 一种复合集流体的制备方法，包括如下步骤：
    将聚合物材料和导电剂混合，所得混合物成膜处理，分别制备第一导电聚合物层和第二导电聚合物层；
    将所述第一导电聚合物层复合于金属箔的第一表面；
    将所述第二导电聚合物层复合于金属箔的第二表面；
    其中，所述第一表面和第二表面位置相对，所述第一导电聚合物层和第二导电聚合物层的材料相同或不同。
  11. 根据权利要求10所述的复合集流体的制备方法，其特征在于，所述复合的方法分别独立地选自如下方法中的一种：
    (1)热压复合；
    (2)通过导电聚合物粘接剂粘合；可选地，所述导电聚合物粘接剂包括丙烯酸酯改性的导电胶、环氧改性的导电胶、PI导电胶及PI改性的导电胶中的一种或多种。
  12. 根据权利要求10或11所述的复合集流体的制备方法，其特征在于，制备得到所述第一导电聚合物层和第二导电聚合物层后，还包括对所述第一导电聚合物层和第二导电聚合物层进行成孔处理的步骤；可选地，所述成孔处理的方法包括干法拉伸成孔和湿法成孔中的一种或两种。
  13. 一种电极片，其特征在于，包括集流体以及设置在所述集流体至少一个表面的电极膜层；所述集流体为权利要求1～9任一项所述的复合集流体或权利要求10～12任 一项所述的制备方法制备得到的复合集流体。
  14. 一种二次电池，其特征在于，包括权利要求13所述的电极片。
  15. 一种用电装置，其特征在于，包括权利要求14所述的二次电池。
PCT/CN2022/120745 2022-09-23 2022-09-23 复合集流体及其制作方法、电极片、二次电池和用电装置 WO2024060176A1 (zh)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103985877A (zh) * 2014-05-30 2014-08-13 合肥国轩高科动力能源股份公司 表面含有导电聚合物膜的锂离子电池集流体处理工艺
CN110556511A (zh) * 2019-09-03 2019-12-10 珠海格力电器股份有限公司 循环性能优异的锂电池负极极片及其制备方法、锂离子电池
CN110718674A (zh) * 2019-10-15 2020-01-21 宁波铵特姆新能源科技有限公司 一种集流体导电涂层及其制备方法
CN110943215A (zh) * 2019-05-31 2020-03-31 宁德时代新能源科技股份有限公司 锂离子二次电池

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103985877A (zh) * 2014-05-30 2014-08-13 合肥国轩高科动力能源股份公司 表面含有导电聚合物膜的锂离子电池集流体处理工艺
CN110943215A (zh) * 2019-05-31 2020-03-31 宁德时代新能源科技股份有限公司 锂离子二次电池
CN110556511A (zh) * 2019-09-03 2019-12-10 珠海格力电器股份有限公司 循环性能优异的锂电池负极极片及其制备方法、锂离子电池
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