WO2023130910A1 - 电池极片的制备方法、电池极片和二次电池 - Google Patents

电池极片的制备方法、电池极片和二次电池 Download PDF

Info

Publication number
WO2023130910A1
WO2023130910A1 PCT/CN2022/138285 CN2022138285W WO2023130910A1 WO 2023130910 A1 WO2023130910 A1 WO 2023130910A1 CN 2022138285 W CN2022138285 W CN 2022138285W WO 2023130910 A1 WO2023130910 A1 WO 2023130910A1
Authority
WO
WIPO (PCT)
Prior art keywords
pole piece
battery
preparation
present application
flame
Prior art date
Application number
PCT/CN2022/138285
Other languages
English (en)
French (fr)
Inventor
曾毓群
欧阳楚英
张玉玺
孙成栋
郑义
Original Assignee
宁德时代新能源科技股份有限公司
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 宁德时代新能源科技股份有限公司 filed Critical 宁德时代新能源科技股份有限公司
Publication of WO2023130910A1 publication Critical patent/WO2023130910A1/zh

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—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
    • 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
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • 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

Definitions

  • the present application relates to the technical field of lithium batteries, in particular to a method for preparing a battery pole piece, a battery pole piece, a secondary battery, a battery module, a battery pack and an electrical device.
  • lithium-ion batteries have been widely used in energy storage power systems such as hydropower, thermal power, wind power 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 application provides a method for preparing a battery pole piece, a battery pole piece, a secondary battery, a battery module, a battery pack, and an electrical device.
  • the battery pole piece prepared by the method of the application has improved electrolyte wettability , thereby improving the efficiency of electrolyte injection and seepage, and enhancing the lithium ion conductivity of the pole piece.
  • the present application provides a method for preparing a battery pole piece, the method comprising the following steps: S1: preparing electrode slurry; S2: coating the electrode slurry on at least one surface of a current collector and drying drying; S3: rolling the dried pole piece; S4: flame-treating the surface of the pole piece after the rolling treatment, to obtain the electrode pole piece.
  • the flame treatment temperature is 200°C-500°C, optionally 250°C-350°C.
  • step S4 the direct contact time between the pole piece surface and the flame is 0.02s-5s, optionally 0.1s-0.5s.
  • the flame treatment equipment includes a gas system and an air intake system, and the gas and the air are sprayed onto the surface of the pole piece through nozzles.
  • the rolled pole piece passes through the nozzle at a constant speed, and the injection direction of the flame is perpendicular to the surface of the pole piece.
  • the distance from the pole piece surface to the nozzle is 50mm-500mm, optionally 100mm-200mm.
  • the ratio of the air flow of the air intake system to the air flow of the gas system is (0.2-5):10, optionally (2-3):10.
  • the gas of the gas system is selected from one or more of hydrogen, carbon monoxide, methane, ethane, propane, butane, pentane, ethylene, propylene, butene, and acetylene.
  • the second aspect of the present application provides a pole piece for a secondary battery, which is prepared according to the method described in the present application, and the pole piece can be a positive pole piece and/or a negative pole piece.
  • the third aspect of the present application provides a secondary battery, which includes the pole piece prepared according to the method described in the present application or the pole piece.
  • a fourth aspect of the present application provides a battery module, including the secondary battery.
  • a fifth aspect of the present application provides a battery pack, including the secondary battery or the battery module.
  • a sixth aspect of the present application provides an electrical device, including at least one of the secondary battery, the battery module, and the battery pack.
  • the inventors of the present application found that by using flame to treat the surface of the pole piece, the wettability of the electrolyte of the pole piece is improved, the efficiency of liquid injection and seepage is improved, and the lithium ion conductivity of the pole piece is enhanced. Thus, the rate performance of the battery can be improved.
  • the method of the present application can also release the internal stress between the materials after the pole piece is rolled through the instantaneous high temperature of the flame, which reduces the expansion of the pole piece and further improves the energy density of the battery.
  • FIG. 1 is a schematic diagram of a secondary battery according to an embodiment of the present application.
  • FIG. 2 is an exploded view of the secondary battery according to one embodiment of the present application shown in FIG. 1 .
  • FIG. 3 is a schematic diagram of a battery module according to an embodiment of the present application.
  • FIG. 4 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG. 5 is an exploded view of the battery pack according to one embodiment of the present application shown in FIG. 4 .
  • FIG. 6 is a schematic diagram of an electrical device in which a secondary battery is used as a power source according to an embodiment of the present application.
  • a secondary battery typically includes a positive pole piece, a negative pole piece, an electrolyte, and a separator.
  • active ions are intercalated and extracted back and forth between the positive electrode and the negative electrode.
  • the electrolyte plays the role of conducting ions between the positive pole piece and the negative pole piece.
  • the separator is arranged between the positive pole piece and the negative pole piece, which mainly plays a role in preventing the short circuit of the positive and negative poles, and at the same time allows ions to pass through.
  • the positive electrode sheet includes a positive electrode sheet including a positive electrode collector and a positive electrode film layer disposed on at least one surface of the positive electrode collector, and the positive electrode film layer includes a positive electrode active material.
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer arranged on at least one surface of the negative electrode current collector, and the negative electrode film layer includes a negative electrode active material.
  • the development of secondary batteries with higher energy density means filling more electrode active materials in a smaller space, so the compaction density of battery pole pieces is getting higher and higher, and the porosity of pole pieces is getting lower and lower.
  • the electrode slurry is not a stable system, after the electrode slurry is applied to the surface of the current collector copper foil or aluminum foil, the solid active material with high density will slowly settle, and the binder with low density will float up, resulting in the surface of the electrode sheet.
  • the binder content is higher than the part away from the surface.
  • the electrode sheet After subsequent baking and rolling, the electrode sheet will form a layer of binder and flat polymer film.
  • the polymer film hinders the infiltration of the electrolyte and the lithium ions in the electrolyte. Diffusion causes a series of problems such as difficulty in filling the battery with electrolyte and poor battery rate performance.
  • the inventor provided a method for preparing a pole piece through a series of studies, which can be used for the treatment of the positive pole piece and/or the negative pole piece of the battery, including the following steps:
  • S4 performing flame treatment on the surface of the pole piece after the rolling treatment, to obtain the electrode pole piece.
  • the inventors found that by flame-treating the surface of the pole piece after rolling, the polymer film formed by the excess binder on the electrode surface can be removed, and micropores leading to the inside of the pole piece can be formed. Improve the electrolyte wettability of the pole piece, improve the efficiency of liquid injection and seepage, enhance the lithium ion conductivity of the pole piece, and improve the rate performance of the battery. At the same time, the high temperature at the moment of the flame can also release the internal stress between the materials after the pole piece is rolled. , reducing the expansion of the pole piece and increasing the energy density of the battery.
  • the electrode slurry includes one or more of electrode active materials, conductive agents, binders, dispersants and solvents.
  • the electrode active material is selected from graphite, nano-silicon, silicon oxide, lithium iron phosphate, lithium nickel cobalt manganate, lithium nickelate, lithium cobaltate, lithium nickel cobalt aluminum, manganic acid One or more of lithium.
  • the conductive agent is selected from one or more of acetylene black, superconducting carbon black, Ketjen black, carbon nanofibers, carbon nanotubes, and graphene.
  • the binder is selected from polyvinylidene fluoride, lithium polyacrylate, polyimide, polyacrylonitrile, sodium carboxymethyl cellulose, polystyrene butadiene copolymer one or more of .
  • the solvent is selected from one or more of N-methylpyrrolidone, dimethyl sulfoxide, N,N-dimethylformamide, water, and ethanol.
  • the dispersant is selected from sodium polyacrylate, polybutadiene acrylonitrile, sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, polyvinylpyrrolidone, polyethylene glycol One or more of octylphenol polyoxyethylene or sulfonate fluorine dispersant.
  • the mass percentage of the electrode active material, conductive agent, binder, and dispersant is: 90% to 99%: 0.5% to 5%: 0.5% to 5%: 0 ⁇ 1%.
  • the current collector is copper foil or aluminum foil.
  • the rolling treatment is cold pressing treatment
  • the thickness of the pole piece after cold pressing is 10-500 microns.
  • the thickness of the pole piece after cold pressing can be 15 ⁇ m, 20 ⁇ m, 25 ⁇ m, 30 ⁇ m, 35 ⁇ m, 40 ⁇ m, 45 ⁇ m, 50 ⁇ m, 55 ⁇ m, 60 ⁇ m, 65 ⁇ m, 70 ⁇ m, 75 ⁇ m, 80 ⁇ m, 85 ⁇ m, 90 ⁇ m, 95 ⁇ m, 100 ⁇ m, 110um, 120um, 130um, 140um, 150um, 160um, 170um, 180um, 190um, 200um, 210um, 220um, 230um, 240um, 250um, 260um, 270um, 280um, 290um, 300um, 50 ⁇ m, 400 ⁇ m, 450 ⁇ m or any value thickness.
  • the examples of the present application prove that any value of the thickness of the pole piece of the present application will not affect the effect of the flame treatment of S4. Therefore, those skilled in the art can reasonably select the thickness of
  • the flame treatment temperature is 200°C-500°C, or any temperature during the flame treatment, for example, the flame treatment temperature can be 210°C, 220°C, 230°C, 240°C Alternatively, the flame treatment temperature may be 400°C, 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, etc.
  • the temperature of the flame treatment is 250°C-350°C or any temperature during the period, for example, the temperature of the flame treatment can be 250°C, 251°C, 252°C, 253°C, 254°C, 255°C , 256°C, 257°C, 258°C, 259°C, 260°C, 261°C, 262°C, 263°C, 264°C, 265°C, 266°C, 267°C, 268°C, 269°C, 270°C, 271°C, 272°C °C, 273°C, 274°C, 275°C, 276°C, 277°C, 278°C, 279°C, 280°C, 281°C, 282°C, 283°C, 284°C, 285°C, 286°C, 287°C, 288°C, 289°C, 290°C, 291°C, 292°C, 293
  • the influence of the flame treatment on the pole piece has a great correlation with temperature.
  • the temperature of the pole piece will be too high, the binder will fail, the expansion of the pole piece will increase, and the rate charging capability will deteriorate.
  • the flame temperature is too low, the internal stress of the pole piece is not fully released, and the effect of flame treatment on inhibiting the expansion of the pole piece, improving liquid absorption, and increasing the charging rate is not obvious.
  • the direct contact time between the pole piece surface and the flame is 0.02s-5s or any value during the period, for example, the direct contact time of the flame treatment can be 0.03s, 0.04s, 0.05s, 0.06s, 0.07s, 0.08s, 0.09s, 0.1s, or, the direct contact time of the flame treatment may be 1s, 2s, 3s, 4s, 5s.
  • the direct contact time of the flame treatment is 0.1s-0.5s or any value therebetween.
  • the direct contact time of the flame treatment may be 0.1s, 0.2s, 0.3s, 0.4s or 0.5s.
  • the influence of the flame treatment on the pole piece is greatly correlated with the direct contact time between the pole piece and the flame
  • the pole piece when the pole piece is in direct contact with the flame for too long, it will cause the pole piece If the temperature is too high, the binder will fail, the expansion of the pole piece will increase, and the rate charging capability will deteriorate.
  • the contact time of the pole piece with the flame is too short, the surface temperature of the pole piece is too low, the internal stress of the pole piece is not fully released, and the effect of flame treatment on inhibiting the expansion of the pole piece, improving liquid absorption, and increasing the charging rate is not obvious.
  • the flame treatment equipment includes a gas system and an air intake system, and the gas and the air are sprayed onto the surface of the pole piece through nozzles.
  • the rolled pole piece passes through the nozzle at a constant speed, and the injection direction of the flame is perpendicular to the surface of the pole piece.
  • the distance from the pole piece surface to the nozzle is 50mm-500mm, optionally 100mm-200mm.
  • the speed at which the pole piece passes through the nozzle and the distance between the surface of the pole piece and the nozzle are all those skilled in the art. It can be selected according to actual needs.
  • the ratio of the air flow of the air intake system to the air flow of the gas system is (0.2-5):10, optionally (2-3):10.
  • the gas of the gas system is selected from one or more of hydrogen, carbon monoxide, methane, ethane, propane, butane, pentane, ethylene, propylene, butene, and acetylene.
  • the method further includes S5: punching the flame-treated pole piece into a desired shape.
  • a secondary battery is provided.
  • the positive electrode sheet includes a positive electrode collector and a positive electrode film layer arranged on at least one surface of the positive electrode collector, and the positive electrode film layer includes a positive electrode active material.
  • the positive electrode current collector has two opposing surfaces in its own thickness direction, and the positive electrode film layer is disposed on any one or both of the two opposing surfaces of the positive electrode current collector.
  • the positive electrode current collector can be a metal foil or a composite current collector.
  • aluminum foil can be used as the metal foil.
  • the composite current collector may include a polymer material base and a metal layer formed on at least one surface of the polymer material base.
  • the composite current collector can be formed by forming metal materials (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as polypropylene (PP), polyethylene terephthalic acid It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • PP polypropylene
  • PET polyethylene glycol ester
  • PBT polybutylene terephthalate
  • PS polystyrene
  • PE polyethylene
  • the positive electrode active material may be a positive electrode active material known in the art for batteries.
  • the positive active material may include at least one of the following materials: olivine-structured lithium-containing phosphate, lithium transition metal oxide, and their respective modified compounds.
  • the present application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials of batteries can also be used. These positive electrode active materials may be used alone or in combination of two or more.
  • 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 (also abbreviated as NCM 523 ), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (also abbreviated as NCM 211 ), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (also abbreviated as 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 LiNi
  • the olivine structure contains Examples of lithium phosphates may include, but are not limited to, lithium iron phosphate (such as LiFePO 4 (also may be abbreviated as LFP)), composite materials of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), lithium manganese phosphate and carbon At least one of a composite material, lithium manganese iron phosphate, and a composite material of lithium manganese iron phosphate and carbon.
  • lithium iron phosphate such as LiFePO 4 (also may be abbreviated as LFP)
  • composite materials of lithium iron phosphate and carbon such as LiMnPO 4
  • LiMnPO 4 lithium manganese phosphate and carbon
  • the positive electrode film layer may further optionally include 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 positive electrode film layer may also optionally include 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 positive electrode sheet can be prepared in the following manner: the above-mentioned components used to prepare the positive electrode sheet, such as positive electrode active material, conductive agent, binder and any other components, are dispersed in a solvent (such as N -methylpyrrolidone) to form a positive electrode slurry; the positive electrode slurry is coated on the positive electrode current collector, and after drying, cold pressing and other processes, the positive electrode sheet can be obtained.
  • a solvent such as N -methylpyrrolidone
  • the negative electrode sheet includes a negative electrode current collector and a negative electrode film layer arranged on at least one surface of the negative electrode current collector, and the negative electrode film layer includes a negative electrode active material.
  • the negative electrode current collector has two opposing surfaces in its own thickness direction, and the negative electrode film layer is disposed on any one or both of the two opposing surfaces of the negative electrode current collector.
  • the negative electrode current collector can use a metal foil or a composite current collector.
  • copper foil can be used as the metal foil.
  • the composite current collector may include a base layer of polymer material and a metal layer formed on at least one surface of the base material of polymer material.
  • Composite current collectors can be formed by metal materials (copper, copper alloys, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on polymer material substrates (such as polypropylene (PP), polyethylene terephthalic acid It is formed on substrates such as ethylene glycol ester (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
  • the negative electrode active material can be a negative electrode active material known in the art for batteries.
  • the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, lithium titanate, and the like.
  • the silicon-based material may be selected from at least one of elemental silicon, silicon-oxygen compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys.
  • the tin-based material may be selected from at least one of simple tin, tin oxide compounds and tin alloys.
  • the present application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials of batteries can also be used. These negative electrode active materials may be used alone or in combination of two or more.
  • the negative electrode film layer may further optionally include a binder.
  • the binder can be selected from styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), poly At least one of methacrylic acid (PMAA) and carboxymethyl chitosan (CMCS).
  • the negative electrode film layer may also optionally include a conductive agent.
  • the conductive agent can be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene and carbon nanofibers.
  • the negative electrode film layer may optionally include other additives, such as thickeners (such as sodium carboxymethylcellulose (CMC-Na)) and the like.
  • thickeners such as sodium carboxymethylcellulose (CMC-Na)
  • CMC-Na sodium carboxymethylcellulose
  • the negative electrode sheet can be prepared in the following manner: the above-mentioned components used to prepare the negative electrode sheet, such as negative electrode active material, conductive agent, binder and any other components, are dispersed in a solvent (such as deionized water) to form a negative electrode slurry; the negative electrode slurry is coated on the negative electrode current collector, and after drying, cold pressing and other processes, the negative electrode sheet can be obtained.
  • a solvent such as deionized water
  • the electrolyte plays the role of conducting ions between the positive pole piece and the negative pole piece.
  • the present application has no specific limitation on the type of electrolyte, which can be selected according to requirements.
  • electrolytes can be liquid, gel or all solid.
  • the electrolyte is an electrolytic solution.
  • the electrolyte solution includes an electrolyte salt and a solvent.
  • the electrolyte salt may be selected from lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bisfluorosulfonyl imide, lithium bistrifluoromethanesulfonyl imide, trifluoromethane At least one of lithium sulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium difluorooxalate borate, lithium difluorodifluorooxalatephosphate and lithium tetrafluorooxalatephosphate.
  • the solvent may be selected from ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, Butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate At least one of ester, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone and diethyl sulfone.
  • the electrolyte may optionally include additives.
  • additives may include negative electrode film-forming additives, positive electrode film-forming additives, and additives that can improve certain performances of the battery, such as additives that improve battery overcharge performance, additives that improve high-temperature or low-temperature performance of batteries, and the like.
  • a separator is further included in the secondary battery.
  • the present application has no particular limitation on the type of the isolation membrane, and any known porous structure isolation membrane with good chemical stability and mechanical stability can be selected.
  • the material of the isolation film can be selected from at least one of glass fiber, non-woven fabric, polyethylene, polypropylene and polyvinylidene fluoride.
  • the separator can be a single-layer film or a multi-layer composite film, and is not particularly limited. When the separator is a multilayer composite film, the materials of each layer may be the same or different, and there is no particular limitation.
  • the positive pole piece, the negative pole piece and the separator can be made into an electrode assembly through a winding process or a lamination process.
  • the secondary battery may include an outer package.
  • the outer package can be used to package the above-mentioned electrode assembly and electrolyte.
  • the outer packaging of the secondary battery may be a hard case, such as a hard plastic case, aluminum case, steel case, and the like.
  • 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 case may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, polybutylene succinate, and the like.
  • FIG. 1 shows a square-shaped 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 a side plate connected to the bottom plate, and the bottom plate and the side plates enclose to form an accommodating cavity.
  • the housing 51 has an opening communicating with the accommodating cavity, and the cover plate 53 can cover the opening to close the accommodating cavity.
  • the positive pole piece, the negative pole piece and the separator can be formed into an electrode assembly 52 through a winding process or a lamination process.
  • the electrode assembly 52 is packaged in the accommodating chamber. Electrolyte is infiltrated in 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.
  • the secondary battery can be assembled into a battery module, and the number of secondary batteries contained in the battery module can be one or more, and the specific number can be selected by those skilled in the art according to the application and capacity of the battery module.
  • FIG. 3 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 .
  • they can also be arranged in other arbitrary ways.
  • the plurality of secondary batteries 5 may be fixed by fasteners.
  • the battery module 4 may also include a case having a housing space in which a plurality of secondary batteries 5 are accommodated.
  • the above-mentioned battery modules can also be assembled into a battery pack, and the number of battery modules contained in the battery pack can be one or more, and the specific number can be selected by those skilled in the art 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 body 2 and a lower box body 3 , the upper box body 2 can cover the lower box body 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 electric device, which includes at least one of the secondary battery, battery module, or battery pack provided in the present application.
  • the secondary battery, battery module, or battery pack can be used as a power source of the electric device, and can also be used as an energy storage unit of the electric device.
  • the electric devices may include mobile devices (such as mobile phones, notebook computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, etc.) , electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc., but not limited thereto.
  • a secondary battery, a battery module or a battery pack can be selected according to its use requirements.
  • FIG. 6 is an example of an electrical device.
  • the electric device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle.
  • a battery pack or a battery module may be used.
  • a device may be a cell phone, tablet, laptop, or the like.
  • the device is generally required to be light and thin, and a secondary battery can be used as a power source.
  • EC ethylene carbonate
  • EMC ethylmethyl carbonate
  • DEC diethyl carbonate
  • a polyethylene film was used as a separator.
  • the battery design capacity is 30Ah.
  • Example 1 The difference from Example 1 is the flame treatment temperature and the time of direct contact with the flame of the negative electrode sheet. See Table 1 for details
  • Example 9 Same as Example 9, except that the density of one side of the negative electrode sheet coating is 235 g/m 2 , the density of both sides of the coating is 470 g/m 2 , and the thickness of cold pressing is 300 ⁇ m.
  • the preparation method of the negative electrode sheet is as follows:
  • EC ethylene carbonate
  • EMC ethylmethyl carbonate
  • DEC diethyl carbonate
  • a polyethylene film was used as a separator.
  • the battery design capacity is 30Ah.
  • Example 15 The difference from Example 15 is the flame treatment temperature of the positive pole piece and the time of direct contact with the flame. See Table 2 for details
  • Example 23 Same as Example 23, except that the density of one side of the positive pole piece coating is 341 g/m 2 , the density of both sides of the coating is 682 g/m 2 , and the thickness of cold pressing is 300 ⁇ m. See Table 2 for details
  • Example 29 is the same as Example 9, except that the positive electrode preparation method is the same as that of Example 23.
  • Example 30 is the same as Example 1, except that the positive electrode preparation method is the same as that of Example 15.
  • Example 31 is the same as Example 5, except that the positive electrode preparation method is the same as that of Example 19. See Table 3 for details.
  • Electrode expansion rate (full charge thickness - cold press thickness) / cold press thickness
  • the expansion of the pole piece can be better improved, the liquid absorption speed can be improved, the liquid absorption time can be reduced, and the rate charging capacity of the battery can be improved.
  • Examples 14 and 28 show that flame treatment improves the performance of the pole piece independent of its thickness.
  • Examples 29-31 show that treating the positive and negative electrodes of the secondary battery at the same time can significantly improve the rate performance of the battery.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Secondary Cells (AREA)

Abstract

本申请提供了一种电池极片的制备方法、电池极片和二次电池。所述方法包括以下步骤：S1：制备电极浆料；S2：将所述电极浆料涂覆于集流体的至少一个表面并烘干；S3：将烘干后的极片进行辊压处理；S4：将辊压处理后的极片表面进行火焰处理，得到所述电极极片。使用本申请的方法制备的电池极片，提高了电池极片的效率，降低了极片的膨胀，从而提高了二次电池的能量密度。

Description

电池极片的制备方法、电池极片和二次电池
相关申请的交叉引用
本申请要求享有于2022年01月04日提交的名称为“电池极片的制备方法、电池极片和二次电池”的中国专利申请202210006282.0的优先权，该申请的全部内容通过引用并入本文中。
技术领域
本申请涉及锂电池技术领域，尤其涉及一种电池极片的制备方法、电池极片、二次电池、电池模块、电池包和用电装置。
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。
发明内容
本申请提供了一种电池极片的制备方法、电池极片、二次电池、电池模块、电池包和用电装置，使用本申请的方法制备的的电池极片，具有改善的电解液浸润性，从而提高了电解液的注液渗液效率，并增强了极片的锂离子导电能力。
第一方面，本申请提供了一种电池极片的制备方法，所述方法包 括以下步骤：S1：制备电极浆料；S2：将所述电极浆料涂覆于集流体的至少一个表面并烘干；S3：将烘干后的极片进行辊压处理；S4：将辊压处理后的极片表面进行火焰处理，得到所述电极极片。
在本申请的任意实施方案中，所述火焰处理温度为200℃-500℃，可选为250℃-350℃。
在本申请的任意实施方案中，步骤S4中，所述极片表面与所述火焰的直接接触时间为0.02s-5s，可选为0.1s-0.5s。
在本申请的任意实施方案中，在所述步骤S4中，进行火焰处理的设备包括燃气系统和空气进气系统，所述燃气和所述空气通过喷嘴喷射到所述极片表面。
在本申请的任意实施方案中，在所述步骤S4中，将辊压处理后的极片以恒定速度通过所述喷嘴，所述火焰的喷射方向与所述极片表面垂直。
在本申请的任意实施方案中，所述极片表面到所述喷嘴的距离为50mm-500mm，可选为100mm-200mm。
在本申请的任意实施方案中，所述空气进气系统的气流量和所述燃气系统的气流量之比为(0.2-5):10，可选为(2-3):10。
在本申请的任意实施方案中，所述燃气系统的燃气选自氢气、一氧化碳、甲烷、乙烷、丙烷、丁烷、戊烷、乙烯、丙烯、丁烯、乙炔中的一种或几种。
本申请的第二方面提供了一种用于二次电池的极片，其根据本申请所述的方法制备，所述极片可以为正极极片和/或负极极片。
本申请的第三方面提供了一种二次电池，其包括根据本申请所述的方法制备的极片或所述的极片。
本申请的第四方面提供了一种电池模块，包括所述的二次电池。
本申请的第五方面提供了一种电池包，包括所述二次电池或所述的电池模块。
本申请的第六方面提供了一种用电装置，包括所述的二次电池、所述的电池模块、所述的电池包中的至少一种。
本申请的发明人发现，通过采用火焰对极片表面进行处理，改善极片的电解液浸润性，提高注液渗液效率，增强极片的锂离子导电能力。从而能提高电池的倍率性能。本申请的方法处理电池极片还能通过火焰瞬间的高温释放极片辊压后材料之间的内部应力，降低了极片的膨胀，进一步提高了电池的能量密度。
附图说明
为了更清楚地说明本申请实施例，下面将对本申请实施例中所需要使用的附图作简单地介绍，显而易见地，下面所描述的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据附图获得其他的附图。
图1是本申请一实施方式的二次电池的示意图。
图2是图1所示的本申请一实施方式的二次电池的分解图。
图3是本申请一实施方式的电池模块的示意图。
图4是本申请一实施方式的电池包的示意图。
图5是图4所示的本申请一实施方式的电池包的分解图。
图6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顶盖组件
具体实施方式
下面结合附图和实施例对本申请的实施方式作进一步详细描述。以下实施例的详细描述和附图用于示例性地说明本申请的原理，但不能用来限制本申请的范围，即本申请不限于所描述的实施例。
在本申请的描述中，需要说明的是，除非另有说明，“多个”的含义是两个以上；术语“上”、“下”、“左”、“右”、“内”、“外”等指示的方位或位置关系仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。此外，术语“第一”、“第二”、“第三”等仅用于描述目的，而不能理解为指示或暗示相对重要性。“垂直”并不是严格意义上的垂直，而是在误差允许范围之内。“平行”并不是严格意义上的平行，而是在误差允许范围之内。
下述描述中出现的方位词均为图中示出的方向，并不是对本申请的具体结构进行限定。在本申请的描述中，还需要说明的是，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或一体地连接；可以是直接相连，也可以通过中间媒介间接相连。对于本领域的普通技术人员而言，可视具体情况理解上述术语在本申请中的具体含义。
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。
其中，正极极片包含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。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。
开发出更高能量密度的二次电池，意味着在较小的空间内填充更多的电极活性材料，因此电池极片的压实密度越来越高，极片的孔隙率越来越低。由于电极浆料并不是一个稳定体系，电极浆料在涂敷到集流体铜箔或铝箔表面之后，密度大的固体活性材料发生缓慢的沉降，密度小的粘结剂上浮，造成电极片表面的粘结剂含量高于远离表面的部分，电极片经过后续的烘烤和辊压后会形成一层粘结剂平整的高分子薄膜，高分子薄膜阻碍电解液的浸润和电解液中锂离子的扩散，造成电池加注电解液困难，电池倍率性能差等一系列问题。
为了解决上述问题，发明人经过一系列研究，提供了一种极片的制备方法，该方法可以用于电池的正极极片处理和/或负极极片处理，包括以下步骤：
S1：制备电极浆料；
S2：将所述电极浆料涂覆于集流体的至少一个表面并烘干；
S3：将烘干后的极片进行辊压处理；
S4：将辊压处理后的极片表面进行火焰处理，得到所述电极极片。
在本申请的制备方法中，发明人发现，通过将辊压之后的极片的表面进行火焰处理，可以清除电极表面过量粘结剂形成的高分子薄膜，形成通向极片内部的微孔，改善极片的电解液浸润性，提高注液渗液效率，增强极片的锂离子导电能力，提高电池的倍率性能，同时火焰瞬间 的高温还可以释放极片辊压后材料之间的内部应力，降低了极片的膨胀，提高了电池的能量密度。
在本申请的任意实施方案中，可以理解的是，S1到S3是本领域的常规步骤。
具体而言，其中在S1中，所述电极浆料包含电极活性物质、导电剂、粘结剂、分散剂和溶剂中的一种或多种。
在本申请的任意实施方案中，所述电极活性物质选自石墨、纳米硅、氧化亚硅、磷酸铁锂、镍钴锰酸锂、镍酸锂、钴酸锂、镍钴铝锂、锰酸锂中的一种或几种。
在本申请的任意实施方案中，所述导电剂选自乙炔黑、超导炭黑、科琴黑、碳纳米纤维、碳纳米管、石墨烯中的一种或几种。
在本申请的任意实施方案中，所述粘结剂选自聚偏氟乙烯、聚丙烯酸锂、聚酰亚胺、聚丙烯腈、羧甲基纤维素钠、聚苯乙烯丁二烯共聚物中的一种或多种。
在本申请的任意实施方案中，所述溶剂选自N-甲基吡咯烷酮、二甲基亚砜、N,N-二甲基甲酰胺、水、乙醇中的一种或几种。
在本申请的任意实施方案中，所述分散剂选自聚丙烯酸钠、聚丁二烯丙烯腈、十二烷基苯磺酸钠、十二烷基硫酸钠、聚乙烯吡咯烷酮、聚乙二醇、辛基苯酚聚氧乙烯或磺酸盐氟分散剂中的一种或者几种。
在本申请的任意实施方案中，所述电极活性物质、导电剂、粘结剂、分散剂之间质量百分含量为：90％～99％：0.5％～5％：0.5％-5％：0～1％。
在本申请的任意实施方案的S2中，所述集流体为铜箔或铝箔。
在本申请的任意实施方案的S3中，所述辊压处理为冷压处理；
优选地，冷压处理后极片的厚度为10-500微米。可选地，冷压处理后极片的厚度可以为15μm、20μm、25μm、30μm、35μm、40μm、45μm、50μm、55μm、60μm、65μm、70μm、75μm、80μm、85μm、90μm、95μm、100μm、110μm、120μm、130μm、140μm、150μm、160μm、170μm、180μm、190μm、200μm、210μm、220μm、230μm、240μm、250μm、260μm、270μm、280μm、290μm、300μm、350μm、400μm、450μm或其中任意数值的厚度。本申请的实施例证明，本申请的任意数值的极片厚度不会影响到S4的火焰处理的效果。因此，本领域技术人员可以根据期望的结果，合理地选择极片的厚度。
在本申请的任意实施方案中，所述火焰处理温度为200℃-500℃，或期间的任意数值的温度，例如，所述火焰处理的温度可以为210℃、220℃、230℃、240℃或者，所述火焰处理的温度可以为400℃、410℃、420℃、430℃、440℃、450℃、460℃、470℃、480℃、490℃等。可选地，所述火焰处理的温度为250℃-350℃或期间任意数值的温度，例如，所述火焰处理的温度可以为250℃、251℃、252℃、253℃、254℃、255℃、256℃、257℃、258℃、259℃、260℃、261℃、262℃、263℃、264℃、265℃、266℃、267℃、268℃、269℃、270℃、271℃、272℃、273℃、274℃、275℃、276℃、277℃、278℃、279℃、280℃、281℃、282℃、283℃、284℃、285℃、286℃、287℃、288℃、289℃、290℃、291℃、292℃、293℃、294℃、295℃、296℃、297℃、298℃、299℃、300℃、301℃、302℃、303℃、304℃、305℃、306℃、307℃、308℃、309℃、310℃、311℃、312℃、313℃、314℃、315℃、316℃、317℃、318℃、319℃、320℃、321℃、322℃、323℃、324℃、325℃、326℃、327℃、328℃、329℃、330℃、331℃、332℃、333℃、334℃、335℃、336℃、 337℃、338℃、339℃、340℃、341℃、342℃、343℃、344℃、345℃、346℃、347℃、348℃或349℃。
根据本申请所述的方法，其中所述火焰处理对极片的影响与温度具有极大地相关性。当火焰温度太高时，会导致极片温度过高，粘结剂失效，极片膨胀变大，倍率充电能力变差。当火焰温度过低时，极片内部应力没有充分释放，火焰处理对于抑制极片膨胀、改善吸液、提升倍率充电效果不明显。
在本申请的任意实施方案中，步骤S4中，所述极片表面与所述火焰的直接接触时间为0.02s-5s或期间的任意数值的时间，例如，所述火焰处理的直接接触时间可以为0.03s、0.04s、0.05s、0.06s、0.07s、0.08s、0.09s、0.1s，或者，所述火焰处理的直接接触时间可以为1s、2s、3s、4s、5s。可选地，所述火焰处理的直接接触时间为0.1s-0.5s或期间的任意数值的时间。例如，所述火焰处理的直接接触时间可以为0.1s、0.2s、0.3s、0.4s或0.5s。
根据本申请所述的方法，其中所述火焰处理对极片的影响与极片与火焰的直接接触时间具有极大地相关性，当极片与火焰直接接触的时间过长时，会导致极片温度过高，粘结剂失效，极片膨胀变大，倍率充电能力变差。当极片与火焰接触的时间太短时，极片表面温度过低，极片内部应力没有充分释放，火焰处理对于抑制极片膨胀、改善吸液、提升倍率充电效果不明显。
在本申请的任意实施方案中，在所述步骤S4中，进行火焰处理的设备包括燃气系统和空气进气系统，所述燃气和所述空气通过喷嘴喷射到所述极片表面。
在本申请的任意实施方案中，在所述步骤S4中，将辊压处理后的极片以恒定速度通过所述喷嘴，所述火焰的喷射方向与所述极片表面垂直。
在本申请的任意实施方案中，所述极片表面到所述喷嘴的距离为50mm-500mm，可选为100mm-200mm。
可以理解的是，为了得到相应的火焰处理温度和极片与火焰直接接触的时间，所述极片通过所述喷嘴的速度以及所述极片表面与所述喷嘴的距离都是本领域技术人员可以根据实际需求选择的。
在本申请的任意实施方案中，所述空气进气系统的气流量和所述燃气系统的气流量之比为(0.2-5):10，可选为(2-3):10。
在本申请的任意实施方案中，所述燃气系统的燃气选自氢气、一氧化碳、甲烷、乙烷、丙烷、丁烷、戊烷、乙烯、丙烯、丁烯、乙炔中的一种或几种。
可以理解的是，为了得到相应的火焰处理温度和极片与火焰直接接触的时间，本领域技术人员可以根据实际需求选择所述空气进气系统的气流量和所述燃气系统的气流量之比。
在本申请的任意实施方案中，所述方法还包括S5：将火焰处理后的极片冲切成期望的形状。
另外，以下适当参照附图对本申请的二次电池、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。
[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，所述正极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可采用铝箔。复合集流体可包括高分子材料基层和形成于高分子材料基层至少一个表面上的金属层。复合集流体可通过将金属材料(铝、铝合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
在一些实施方式中，正极活性材料可采用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。
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。
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。
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；将正极浆料涂覆在正极集流体上，经烘干、冷压等工序后，即可得到正极极片。
[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，所述负极集流体可采用金属箔片或复合集流体。例如，作为金属箔片，可以采用铜箔。复合集流体可包括高分子材料基层和形成于高分子材料基材至少一个表面上的金属层。复合集流体可通过将金属材料(铜、铜合金、镍、镍合金、钛、钛合金、银及银合金等)形成在高分子材料基材(如聚丙烯(PP)、聚对苯二甲酸乙二 醇酯(PET)、聚对苯二甲酸丁二醇酯(PBT)、聚苯乙烯(PS)、聚乙烯(PE)等的基材)上而形成。
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。
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。
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。
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。
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；将负极浆料涂覆在负极集流体上，经烘干、冷压等工序后，即可得到负极极片。
[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、四氟硼酸锂、高氯酸锂、六氟砷酸锂、双氟磺酰亚胺锂、双三氟甲磺酰亚胺锂、三氟甲磺酸锂、二氟磷酸锂、二氟草酸硼酸锂、二草酸硼酸锂、二氟二草酸磷酸锂及四氟草酸磷酸锂中的至少一种。
在一些实施方式中，溶剂可选自碳酸亚乙酯、碳酸亚丙酯、碳酸甲乙酯、碳酸二乙酯、碳酸二甲酯、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯、碳酸亚丁酯、氟代碳酸亚乙酯、甲酸甲酯、乙酸甲酯、乙酸乙酯、乙酸丙酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、丁酸甲酯、丁酸乙酯、1,4-丁内酯、环丁砜、二甲砜、甲乙砜及二乙砜中的至少一种。
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，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1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2，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3是作为一个示例的电池模块4。参照图3，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4和图5是作为一个示例的电池包1。参照图4和图5，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6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
以下，说明本申请的实施例。下面描述的实施例是示例性的，仅用于解释本申请，而不能理解为对本申请的限制。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。
实施例1
负极极片的制备
(1)将石墨、羧甲基纤维素钠、丁苯橡胶、导电炭黑按照95.6％：1.2％：1.8％：1.4％加入到搅拌机中，然后加去离子水酮使得浆料的固含量达到52％，搅拌均匀制成电极浆料；
(2)将制成的电极浆料均匀的涂敷在6μm铜箔表面，涂层单面面密度为91g/m 2，涂层双面面密度为182g/m 2并烘干成极片；
(3)将烘干后的电极片冷压成120μm的极片；
(4)将冷压后的极片用火焰进行处理。调整空气系统流量和乙烷燃气系统流量的比例为0.2:10，混合气体气流速度为2L/min，将待处理极片以5m/min速度通过燃烧系统的火焰；使得所述火焰处理的温度为190℃，极片与火焰直接接触的时间为0.3s；
(5)将火焰处理后的极片冲切成固定形状，得到锂离子电池负极极片。
正极极片的制备
(1)将磷酸铁锂、导电炭黑、PVDF、聚乙烯吡咯烷酮按照96.9％：1％：2％：0.1％加入到搅拌机中，然后加入氮甲基吡咯烷酮使得浆料的固含量达到65％，搅拌均匀制成电极浆料；
(2)将制成的电极浆料均匀的涂敷在12μm铝箔表面，涂层单面面密度为175g/m 2，涂层双面面密度为350g/m 2并烘干成极片；
(3)将烘干后的电极片冷压成158μm的极片；
(4)将极片冲切成固定形状，得到锂离子电池正极极片。
电解液的制备
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照按体积比1:1:1进行混合得到有机溶剂，接着将充分干燥的锂盐LiPF 6溶解于上述有机溶剂中，配制成浓度为1mol/L的电解液。
隔离膜的制备
使用聚乙烯膜作为隔离膜。
二次电池的制备
将正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正极极片和负极极片之间起到隔离的作用，然后卷绕得到电极组件；将电极组件置于外包装中，干燥后注入电解液，经过真空封装、静置、化成、整形等工序，得到二次电池。电池设计容量30Ah。
实施例2～13
与实施例1不同的是，所述负极极片的火焰处理温度、与火焰直接接触的时间。详见表1
实施例14
与实施例9相同，不同的是，所述负极极片涂层单面面密度为235g/m 2，涂层双面面密度为470g/m 2，冷压厚度是300μm。
对比例1
与实施例1不同的是，所述负极极片的制备方法如下：
负极极片的制备
(1)将石墨、羧甲基纤维素钠、丁苯橡胶、导电炭黑按照95.6％：1.2％：1.8％：1.4％加入到搅拌机中，然后加去离子水酮使得浆料的固含量达到52％，搅拌均匀制成电极浆料；
(2)将制成的电极浆料均匀的涂敷在6μm铜箔表面，涂层单面面密度为91g/m 2，涂层双面面密度为182g/m 2并烘干成极片；
(3)将烘干后的电极片冷压成120μm的极片；
(4)将极片冲切成固定形状，得到锂离子电池负极极片。
实施例15
负极极片的制备
同对比例1
正极极片的制备
(1)将磷酸铁锂、导电炭黑、PVDF、聚乙烯吡咯烷酮按照96.9％：1％：2％：0.1％加入到搅拌机中，然后加入氮甲基吡咯烷酮使得浆料的固含量达到65％，搅拌均匀制成电极浆料；
(2)将制成的电极浆料均匀的涂敷在12μm铝箔表面，涂层单面面密度为175g/m 2，涂层双面面密度为350g/m 2并烘干成极片；
(3)将烘干后的电极片冷压成158μm的极片；
(4)将冷压后的极片用火焰进行处理。调整空气系统流量和乙烷燃气系统流量的比例为0.2:10，混合气体气流速度为2L/min，将待处理极片以5m/min速度通过燃烧系统的火焰；使得所述火焰处理的温度为190℃，极片与火焰直接接触的时间为0.3s；
(5)将火焰处理后的极片冲切成固定形状，得到锂离子电池极片。
电解液的制备
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照按体积比1:1:1进行混合得到有机溶剂，接着将充分干燥的锂盐LiPF 6溶解于上述有机溶剂中，配制成浓度为1mol/L的电解液。
隔离膜的制备
使用聚乙烯膜作为隔离膜。
二次电池的制备
将正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正极极片和负极极片之间起到隔离的作用，然后卷绕得到电极组件；将电极组件置于外包装中，干燥后注入电解液，经过真空封装、静置、化成、整形等工序，得到二次电池。电池设计容量30Ah。
实施例16～27
与实施例15不同的是，所述正极极片的火焰处理温度、与火焰直接接触的时间。详见表2
实施例28
与实施例23相同，不同的是，所述正极极片涂层单面面密度为341g/m 2，涂层双面面密度为682g/m 2，冷压厚度是300μm。详见表2
实施例29-31
实施例29同实施例9，不同之处在于其正极制备方法同实施例23。实施例30同实施例1，不同之处在于其正极制备方法同实施例15。实施例31同实施例5，不同之处在于其正极制备方法同实施例19。详见表3。
性能测试
将上述实施例1～31和对比例1得到的二次电池进行性能测试。测试结果如下表1所示。
极片膨胀测试
将上述实施例1～31和对比例1提供的锂离子电池室温下以10A的电流恒流充电至3.65V，然后3.65V恒压充电至电流降低至1.5A，停止充电，将充满电的电池在水、氧气含量低于1ppm的手套箱中解剖，用千分尺测量正极极片和负极极片的厚度；
用下面公式计算极片的满电膨胀率：
极片膨胀率＝(满电厚度-冷压厚度)/冷压厚度
吸液时间测试
将130g电解液加入到上述实施例1～31和对比例1提供的待注液锂离子电池的注液杯中，然后抽真空到-85KPa，保持10S，开始计时，待注液杯中电解液完全渗入电池内部，结束计时，改时间为吸液时间。
2C充电横流比
将实施例1-4和对比例1提供的锂离子电池室温下以60A的电流恒流充电至3.65V，充电容量记作C1，然后3.65V恒压充电至电流降低至1.5A，静止10min；然后以10A电流横流放电到2.5V，放电容量记作C2
用下面公式计算3C充电横流比：
2C充电横流比＝C1/C2。
上述性能测试的结果分别见表1-表3
表1
Figure PCTCN2022138285-appb-000001
Figure PCTCN2022138285-appb-000002
表2
Figure PCTCN2022138285-appb-000003
表3
Figure PCTCN2022138285-appb-000004
从表中实施例1-28与对比例1之间的对比可以看出，正极极片和负极极片经过火焰处理后，电池的吸液时间可以明显降低。
当极片与火焰接触的时间太长(实施例4和18)或者火焰温度太高(实施例2、6、16和20)时，会导致极片温度过高，粘结剂失效，极片膨胀变大，倍率充电能力变差。其中，过高的温度对极片的性能影响尤其明显。
但当极片与火焰接触的时间适宜并且火焰温度适宜(实施例9和23)时，能较好的改善极片膨胀，提高吸液速度，降低吸液时间，改善电池的倍率充电能力。
当极片与火焰接触的时间太短(实施例3和17)或者火焰温度过低(实施例1和15)时，极片表面温度过低，极片内部应力没有充分释放，火焰处理对于抑制极片膨胀、改善吸液、提升倍率充电效果不明显。
从表1中实施例1-13和实施例15-27之间的对比可以看出，在相同的火焰处理条件，经过火焰处理的负极极片对于改善电池极片膨胀、电池吸液速度和倍率充电能力较为明显；火焰处理对正极极片膨胀的改善作用不大，但仍然可以明显改善电池的吸液速度，提升电池的倍率性能。
实施例14和实施例28表明，火焰处理对极片性能的改进与其厚度无关。实施例29-31表明，同时处理二次电池的正极和负极，可以更显著地提升电池的倍率性能。
以上对比可见，无论是正极极片的火焰处理还是负极极片的火焰处理，均可以改善电池的吸液速度，提高注液效率，改善电池的倍率充电能力，对负极极片进行火焰处理对于改善电极膨胀更显著。
虽然已经参考优选实施例对本申请进行了描述，但在不脱离本申请的范围的情况下，可以对其进行各种改进并且可以用等效物替换其中的部件。尤其是，只要不存在结构冲突，各个实施例中所提到的各项技术特征均可以任意方式组合起来。本申请并不局限于文中公开的特定实施例，而是包括落入权利要求的范围内的所有技术方案。

Claims (13)

  1. 一种电池极片的制备方法，所述制备方法包括以下步骤：
    S1：制备电极浆料；
    S2：将所述电极浆料涂覆于集流体的至少一个表面并烘干；
    S3：将烘干后的极片进行辊压处理；
    S4：将辊压处理后的极片表面进行火焰处理，得到所述电极极片。
  2. 根据权利要求1所述的制备方法，其中，所述火焰处理温度为200℃-500℃，可选为250℃-350℃。
  3. 根据权利要求1或2所述的制备方法，其中，步骤S4中，所述极片表面与所述火焰的直接接触时间为0.02s-5s，可选为0.1s-0.5s。
  4. 根据权利要求1至3中任一项所述的制备方法，其中，在所述步骤S4中，进行火焰处理的设备包括燃气系统和空气进气系统，所述燃气和所述空气通过喷嘴喷射到所述极片表面。
  5. 根据权利要求4所述的制备方法，其中，在所述步骤S4中，将辊压处理后的极片以恒定速度通过所述喷嘴，所述火焰的喷射方向与所述极片表面垂直。
  6. 根据权利要求4或5所述的制备方法，其中，所述极片表面到所述喷嘴的距离为50mm-500mm，可选为100mm-200mm。
  7. 根据权利要求4至6中任一项所述的制备方法，其中，所述空气进气系统的气流量和所述燃气系统的气流量之比为(0.2-5):10，可选为(2-3):10。
  8. 根据权利要求4至7中任一项所述的制备方法，其中，所述燃气系统的燃气选自氢气、一氧化碳、甲烷、乙烷、丙烷、丁烷、戊烷、乙烯、丙烯、丁烯、乙炔中的一种或几种。
  9. 一种用于二次电池的极片，其根据权利要求1至8中任一项所述的方法制备，所述极片可以为正极极片和/或负极极片。
  10. 一种二次电池，包括根据权利要求1至9中任一项所述的方法制备的极片或如权利要求10所述的极片。
  11. 一种电池模块，包括根据权利要求12所述的二次电池。
  12. 一种电池包，包括根据权利要求10所述的二次电池或根据权利要求11所述的电池模块。
  13. 一种用电装置，包括根据权利要求10所述的二次电池、根据权利要求11所述的电池模块、根据权利要求12所述的电池包中的至少一种。
PCT/CN2022/138285 2022-01-04 2022-12-12 电池极片的制备方法、电池极片和二次电池 WO2023130910A1 (zh)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202210006282.0A CN116435455A (zh) 2022-01-04 2022-01-04 电池极片的制备方法、电池极片和二次电池
CN202210006282.0 2022-01-04

Publications (1)

Publication Number Publication Date
WO2023130910A1 true WO2023130910A1 (zh) 2023-07-13

Family

ID=87073068

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2022/138285 WO2023130910A1 (zh) 2022-01-04 2022-12-12 电池极片的制备方法、电池极片和二次电池

Country Status (2)

Country Link
CN (1) CN116435455A (zh)
WO (1) WO2023130910A1 (zh)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117219725A (zh) * 2023-11-08 2023-12-12 宁德时代新能源科技股份有限公司 极片表面处理装置及工艺、极片生产设备、电池生产线

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101714671A (zh) * 2008-09-30 2010-05-26 三洋电机株式会社 非水电解质二次电池
JP2010146887A (ja) * 2008-12-19 2010-07-01 Panasonic Corp 非水系二次電池用電極とその製造方法および非水系二次電池
JP2012195134A (ja) * 2011-03-16 2012-10-11 Furukawa Electric Co Ltd:The リチウム遷移金属シリケート系正極活物質材料及び非水電解質２次電池用正極の製造方法
JP2013246971A (ja) * 2012-05-25 2013-12-09 Toyota Motor Corp 電池及びその製造方法
CN104409695A (zh) * 2014-11-27 2015-03-11 江西先材纳米纤维科技有限公司 火焰沉积热处理硅电极的改性方法
CN109888171A (zh) * 2019-01-29 2019-06-14 江苏塔菲尔新能源科技股份有限公司 电池正极片的处理方法

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101714671A (zh) * 2008-09-30 2010-05-26 三洋电机株式会社 非水电解质二次电池
JP2010146887A (ja) * 2008-12-19 2010-07-01 Panasonic Corp 非水系二次電池用電極とその製造方法および非水系二次電池
JP2012195134A (ja) * 2011-03-16 2012-10-11 Furukawa Electric Co Ltd:The リチウム遷移金属シリケート系正極活物質材料及び非水電解質２次電池用正極の製造方法
JP2013246971A (ja) * 2012-05-25 2013-12-09 Toyota Motor Corp 電池及びその製造方法
CN104409695A (zh) * 2014-11-27 2015-03-11 江西先材纳米纤维科技有限公司 火焰沉积热处理硅电极的改性方法
CN109888171A (zh) * 2019-01-29 2019-06-14 江苏塔菲尔新能源科技股份有限公司 电池正极片的处理方法

Also Published As

Publication number Publication date
CN116435455A (zh) 2023-07-14

Similar Documents

Publication Publication Date Title
US20230116710A1 (en) Negative electrode current collector, secondary battery containing the same, battery module, battery pack, and power consumption apparatus
WO2023221380A1 (zh) 负极极片及其制备方法、二次电池、电池模块、电池包及用电装置
WO2023130910A1 (zh) 电池极片的制备方法、电池极片和二次电池
WO2024012166A1 (zh) 二次电池及用电装置
WO2024016891A1 (zh) 预锂化极片及其制备方法、二次电池和用电装置
WO2023082924A1 (zh) 极片、锂离子电池、电池模块、电池包及用电装置
WO2023071807A1 (zh) 隔膜及其制备方法、二次电池、电池模块、电池包和用电装置
WO2023142024A1 (zh) 一种长寿命二次电池及电池模块、电池包和用电装置
WO2023010927A1 (zh) 二次电池、电池模块、电池包及用电装置
WO2023004633A1 (zh) 一种电池、电池模块、电池包和用电装置
WO2023141954A1 (zh) 锂离子电池、电池模块、电池包和用电装置
WO2023133882A1 (zh) 隔膜及其相关的二次电池、电池模块、电池包和用电装置
WO2023236102A1 (zh) 二次电池及其制备方法、用电装置
WO2023133825A1 (zh) 电池包和用电装置
WO2023044752A1 (zh) 锂离子电池、电池模块、电池包及用电装置
US20240145791A1 (en) Secondary battery and preparation method thereof, battery module, battery pack, and electric apparatus
WO2023174012A1 (zh) 正极极片、锂离子二次电池、电池模块、电池包和用电装置
WO2023060534A1 (zh) 一种二次电池
WO2024007267A1 (zh) 负极极片、其制造方法、二次电池、电池模组、电池包及用电装置
WO2023225797A1 (zh) 二次电池用正极极片和二次电池
WO2024016122A1 (zh) 一种极片、电池单体、电池及用电装置
WO2023240485A1 (zh) 正极极片及其制备方法、二次电池、电池模块、电池包及用电装置
WO2024077473A1 (zh) 集流体及其制备方法、电极极片、二次电池以及用电装置
WO2024007196A1 (zh) 正极极片、二次电池及用电装置
WO2023159385A1 (zh) 正极极片及二次电池、电池模块、电池包和用电装置，及平衡电池内部电压差的方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22918360

Country of ref document: EP

Kind code of ref document: A1