WO2023071706A1 - 复合聚酰亚胺隔膜及其制备方法、二次电池 - Google Patents

复合聚酰亚胺隔膜及其制备方法、二次电池 Download PDF

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WO2023071706A1
WO2023071706A1 PCT/CN2022/123066 CN2022123066W WO2023071706A1 WO 2023071706 A1 WO2023071706 A1 WO 2023071706A1 CN 2022123066 W CN2022123066 W CN 2022123066W WO 2023071706 A1 WO2023071706 A1 WO 2023071706A1
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preparation
polyamic acid
composite
diaphragm
secondary battery
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PCT/CN2022/123066
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English (en)
French (fr)
Inventor
李世达
钟奇能
杨丽美
吴译晨
薛逸凡
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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 EP22885589.6A priority Critical patent/EP4317319A1/en
Publication of WO2023071706A1 publication Critical patent/WO2023071706A1/zh
Priority to US18/489,461 priority patent/US20240076419A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/12—Polymerisation in non-solvents
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G73/00—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups C08G12/00 - C08G71/00
    • C08G73/06—Polycondensates having nitrogen-containing heterocyclic rings in the main chain of the macromolecule
    • C08G73/10—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
    • C08G73/1067—Wholly aromatic polyimides, i.e. having both tetracarboxylic and diamino moieties aromatically bound
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F8/00—Chemical modification by after-treatment
    • C08F8/30—Introducing nitrogen atoms or nitrogen-containing groups
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
    • C08G73/00—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups C08G12/00 - C08G71/00
    • C08G73/06—Polycondensates having nitrogen-containing heterocyclic rings in the main chain of the macromolecule
    • C08G73/10—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
    • C08G73/1042—Copolyimides derived from at least two different tetracarboxylic compounds or two different diamino compounds
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/20—Manufacture of shaped structures of ion-exchange resins
    • C08J5/22—Films, membranes or diaphragms
    • C08J5/2206—Films, membranes or diaphragms based on organic and/or inorganic macromolecular compounds
    • C08J5/2218—Synthetic macromolecular compounds
    • C08J5/2256—Synthetic macromolecular compounds based on macromolecular compounds obtained by reactions other than those involving carbon-to-carbon bonds, e.g. obtained by polycondensation
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L79/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen or carbon only, not provided for in groups C08L61/00 - C08L77/00
    • C08L79/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
    • C08L79/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
    • 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
    • H01M10/04—Construction or 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
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/423—Polyamide resins
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2379/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen, or carbon only, not provided for in groups C08J2361/00 - C08J2377/00
    • C08J2379/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
    • C08J2379/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
    • 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 batteries, in particular to a composite polyimide diaphragm, a preparation method thereof, and a secondary battery.
  • the battery separator plays the role of isolating the positive and negative electrodes, so that the ions in the electrolyte can travel freely in the positive and negative electrodes, but the electrons cannot pass through.
  • the quality of the separator directly affects the battery's charge-discharge cycle life, flame retardancy and other safety performance indicators.
  • Polyimide (PI) is a new type of insulating material with good comprehensive performance. It has excellent thermal stability and mechanical properties. It can be used for a long time at a temperature above 300 ° C. It is an ideal battery diaphragm material.
  • the polyimide diaphragm prepared in the prior art often easily causes a micro-short circuit in the positive and negative electrodes of the secondary battery, thereby causing safety accidents such as battery explosion and fire.
  • the present application is made in view of the above problems, and its purpose is to provide a composite polyimide separator, a preparation method thereof, and a secondary battery, aiming at improving the safety performance of the secondary battery.
  • the first aspect of the application provides a method for preparing a composite polyimide diaphragm, comprising:
  • the present application can obtain a polyamic acid diaphragm with a composite structure by performing interfacial polymerization reaction on the surface of the porous polyamic acid membrane, and then carry out imidization treatment on the composite polyamic acid diaphragm in the vapor of the imidization reagent , a composite polyimide diaphragm with a dense surface and a loose bottom can be obtained. Since the imidization treatment is carried out by placing the composite polyamic acid membrane in the steam of the imidization reagent, instead of directly heating the membrane at high temperature, under the catalysis of the imidization reagent, the imidization can be greatly reduced.
  • the temperature of the amination reaction can be used to prepare a composite polyimide diaphragm with a smooth surface and no cracks.
  • the composite polyamic acid membrane is imidized in the vapor of the imidization reagent, it can avoid direct contact with the liquid imidization reagent, so that the imidization reaction speed will not be too fast, and there is It is beneficial to obtain a composite polyimide diaphragm with uniform pore distribution.
  • step (b) the time, temperature and frequency of interfacial polymerization are controlled, so that the pore size of the surface layer of the composite polyimide diaphragm can be adjusted.
  • the time and temperature parameters of the interfacial polymerization reaction and increasing the number of layers of the composite membrane by increasing the number of interfacial polymerization reactions, the pore size of the surface membrane can be controlled within an appropriate range according to actual use requirements.
  • step (b) the time of the interfacial polymerization reaction is 1s to 120s, preferably 10s to 60s; and/or
  • the temperature of the interfacial polymerization reaction is 10°C to 45°C, preferably 25°C to 45°C; and/or
  • the number of interfacial polymerization reactions is n ⁇ 1.
  • the pore size of the surface membrane of the composite polyimide diaphragm can be regulated, which is conducive to the formation of a composite polyimide diaphragm with a dense surface and a loose bottom.
  • the concentration of the aqueous diamine solution is (0.01 ⁇ 10 -2 ) to (5 ⁇ 10 -2 ) g/mL, preferably (0.01 ⁇ 10 -2 ) to (2 ⁇ 10 -2 ) g/mL; and/or
  • the concentration of the acid chloride organic solution is (0.005 ⁇ 10 -2 ) to (1 ⁇ 10 -2 ) g/mL, preferably (0.05 ⁇ 10 -2 ) to (0.5 ⁇ 10 -2 ) g/mL.
  • the concentration of the aqueous diamine solution is (0.01 ⁇ 10 -2 ) to (5 ⁇ 10 -2 ) g/mL, preferably (0.01 ⁇ 10 -2 ) to (2 ⁇ 10 -2 ) g/mL; and/or the concentration of the acid chloride organic solution is (0.005 ⁇ 10 -2 ) ⁇ (1 ⁇ 10 -2 ) g/mL, preferably (0.05 ⁇ 10 -2 ) ⁇ (0.5 ⁇ 10 -2 ) g/mL.
  • the interfacial polymerization reaction is beneficial to occur.
  • the diamine monomer in the diamine aqueous solution comprises m-phenylenediamine or p-phenylenediamine;
  • the acid chloride monomer in the acid chloride organic solution comprises pyromelliticoyl chloride or bipylloyl chloride.
  • the temperature of the imidization reaction is 60°C to 250°C, preferably 65°C to 120°C; and/or
  • the imidization reaction time is 2h-10h, preferably 4h-8h.
  • the imidization reagent comprises an acid anhydride and a tertiary amine, wherein the volume ratio of the acid anhydride to the tertiary amine is 1:(0.7 ⁇ 1.5).
  • an appropriate concentration of the imidization reagent can be obtained, which is conducive to improving the efficiency of the imidization reaction.
  • the acid anhydride comprises one or more of acetic anhydride, propionic anhydride, succinic anhydride, benzoic anhydride and phthalic anhydride; and/or
  • Tertiary amines include one or more of triethylamine, tributylamine, trimethylamine, dodecyldimethylamine and hexadecyldimethylamine.
  • the method also includes: drying the composite polyamic acid diaphragm obtained in step (b), wherein,
  • the temperature of the drying treatment is 25°C to 45°C, preferably 25°C to 35°C; and/or
  • the drying treatment time is 50 min to 70 min, preferably 50 min to 60 min.
  • step (a) comprises:
  • the polyamic acid membrane with higher porosity can be obtained.
  • the total mass of dianhydride, diamine, polar solvent and pore-forming agent is 100%, and the sum of the mass of dianhydride and diamine is 10% to 10%. 30%; preferably, the molar ratio of diamine to dianhydride is 1:(1.005-1.01); the mass of polar solvent is 70%-90%; the mass of pore-forming agent is 1%-7%.
  • the diamine comprises 3,3'-dimethyl-4,4'-diaminodiphenylmethane and N,N'-bis(4-aminophenoxyphenyl)benzophenone tetra
  • the imides; and/or dianhydrides comprising 3,3',4,4'-benzophenonetetracarboxylic dianhydride, 4,4'-triphenylene ether dianhydride and pyromellitic anhydride
  • the pore-forming agent comprises polyvinylpyrrolidone or polyethylene glycol; preferably, the molecular weight of polyethylene glycol is 200-400; and/or the polar solvent comprises N-methylpyrrolidone, N , at least one of N-dimethylformamide and tetrahydrofuran.
  • a suitable diamine, dianhydride and polar solvent it is beneficial to the polycondensation reaction to obtain a polyamic acid solution; by selecting a suitable pore-forming agent, it is beneficial to form a polyamic acid solution with a uniform shape and size.
  • the air bubbles are conducive to the pores contained in the subsequently formed porous polyamic acid film to be relatively uniform in shape and size.
  • the thickness of the polyamic acid casting solution coated on the substrate is 5 ⁇ m to 200 ⁇ m, preferably 40 ⁇ m to 200 ⁇ m.
  • the coagulation bath includes at least one of methanol, ethanol, n-butanol and water; and/or the temperature of the coagulation bath is 25°C to 45°C, preferably 25 to 30°C ; and/or the immersion time is 30 min to 180 min, preferably 30 min to 120 min.
  • the second aspect of the present application also provides a composite polyimide diaphragm prepared by the preparation method described in the first aspect of the present application.
  • the composite polyimide diaphragm includes a base film, and at least one surface film disposed on the surface of the base film.
  • a composite polyimide diaphragm with a composite structure can be obtained.
  • the composite polyimide diaphragm in the present application The pore size of the surface membrane of the separator can be adjusted. By adjusting the pore size of the surface film, a composite polyimide separator with uniform pore distribution can be obtained, and at the same time, the porosity and air permeability of the separator can be improved, the puncture strength of the separator can be enhanced, and the micro-short circuit of the positive and negative electrodes of the secondary battery can be reduced. , to improve the safety performance of the secondary battery.
  • the third aspect of the present application provides a secondary battery, comprising the composite polyimide separator prepared according to the preparation method of the first aspect of the present application or the composite polyimide separator of the second aspect of the present application.
  • a fourth aspect of the present application provides a battery module including the secondary battery of the third aspect of the present application.
  • a fifth aspect of the present application provides a battery pack, including the battery module of the fourth aspect of the present application.
  • the sixth aspect of the present application provides an electric device, including at least one selected from the secondary battery of the third aspect of the present application, the battery module of the fourth aspect of the present application, or the battery pack of the fifth aspect of the present application. kind.
  • FIG. 1 is a schematic structural view of a composite polyimide diaphragm according to an embodiment of the present application.
  • Fig. 2 is a partial enlarged view of the surface film of the composite polyimide diaphragm according to an embodiment of the present application.
  • Fig. 3 is a schematic structural diagram of an imidization reaction device according to an embodiment of the present application.
  • FIG. 4 is a schematic diagram of a secondary battery according to an embodiment of the present application.
  • FIG. 5 is an exploded view of a secondary battery according to an embodiment of the present application shown in FIG. 5 .
  • FIG. 6 is a schematic diagram of a battery module according to an embodiment of the present application.
  • FIG. 7 is a schematic diagram of a battery pack according to an embodiment of the present application.
  • FIG. 8 is an exploded view of a battery pack according to an embodiment of the present application shown in FIG. 7 .
  • FIG. 9 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.
  • ranges disclosed herein are defined in terms of lower and upper limits, and 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 and may be combined arbitrarily, ie 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, it is understood that ranges of 60-110 and 80-120 are contemplated. Additionally, if the minimum range values 1 and 2 are listed, and if the maximum range values 3, 4, and 5 are listed, 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" indicates that all real numbers between "0-5" have been listed in this article, and "0-5" is only an abbreviated representation of the combination of these values.
  • 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 in sequence, and may also include steps (b) and (a) performed in sequence.
  • steps (c) means that step (c) may be added to the method in any order, for example, 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) and so on.
  • the “comprising” and “comprising” mentioned in this application mean open or closed.
  • the “comprising” and “comprising” may mean that other components not listed may be included or included, or only listed components may be included or included.
  • the term "or” is inclusive unless otherwise stated.
  • the phrase "A or B” means “A, B, or both A and B.” More specifically, the condition "A or B” is satisfied by either of the following: 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).
  • the polyimide diaphragm prepared by the prior art usually needs to be subjected to high-temperature heat treatment during the imidization process, and the diaphragm is easily curled and deformed due to the high reaction temperature. , The problem of surface cracking.
  • the polyimide diaphragm prepared by the prior art is usually a single-layer integrated structure. During the preparation process, the surface pore size of the diaphragm cannot be adjusted according to the actual use requirements of the secondary battery. The surface pore size of the separator is usually large, which easily causes the problem of internal short circuit of the positive and negative electrodes of the secondary battery.
  • the present application proposes a preparation method of a polyimide diaphragm, which can obtain a polyimide diaphragm of a composite structure by adopting interfacial polymerization.
  • the surface of the diaphragm is dense, the bottom is loose, and The surface pore size and surface density of the separator can be adjusted by controlling the parameters of the interfacial polymerization reaction.
  • the method reacts by placing the diaphragm in the vapor of the imidization reagent instead of directly heating the diaphragm at high temperature, so under the catalysis of the imidization reagent, it can be extremely The temperature of the imidization reaction is greatly reduced, so that a composite polyimide diaphragm with a smooth surface and no cracks can be prepared.
  • the first aspect of the present application provides a method for preparing a composite polyimide diaphragm, including:
  • the composite polyamic acid diaphragm can be obtained by interfacial polymerization reaction of the diamine aqueous solution and the acid chloride organic solution on the surface of the porous polyamic acid membrane, and then the composite polyamic acid diaphragm is placed in the vapor of the imidization reagent The imidization reaction is carried out to obtain a polyimide diaphragm with a composite structure.
  • a composite film with a multi-layer structure can be formed on the porous polyamic acid film, and then imidization treatment can be carried out, which is different from the prior art.
  • the imidization treatment is carried out by placing the composite polyamic acid membrane in the steam of the imidization reagent, instead of directly heating the membrane at high temperature, the catalysis of the imidization reagent Under the action of the imidization reaction, the temperature of the imidization reaction can be greatly reduced, thus a composite polyimide diaphragm with a smooth surface and no cracks can be prepared; and because the composite polyamic acid diaphragm is imidized in the vapor of the imidization reagent Amination, so that it can avoid direct contact with liquid imidization reagents, so that the speed of imidization reaction will not be too fast, which is beneficial to obtain a composite polyimide diaphragm with uniform pore distribution.
  • the time, temperature and frequency of the interfacial polymerization reaction are controlled, so that the surface membrane pore size of the composite polyimide membrane can be adjusted.
  • the pore size of the surface membrane can be controlled within an appropriate range according to actual use requirements .
  • it is beneficial to form a dense surface film which can increase the porosity and air permeability of the separator, enhance the puncture strength of the separator, reduce the occurrence of micro-short circuits in the positive and negative electrodes of the secondary battery, and improve Safety performance of secondary batteries.
  • the time for the interfacial polymerization reaction is 1s-120s, preferably 10s-60s, more preferably 10s-20s.
  • the time of the interfacial polymerization reaction in an appropriate range, it is beneficial to form a polyamic acid membrane with an appropriate thickness and a small surface pore size.
  • the temperature of the interfacial polymerization reaction is 10°C-45°C, preferably 25°C-45°C; more preferably 25°C-35°C.
  • the temperature of the interfacial polymerization reaction in an appropriate range, it is beneficial to increase the speed of the interfacial polymerization reaction and make the reaction more complete, thereby forming a polyamic acid diaphragm with a dense surface.
  • the number of interfacial polymerization reactions is n ⁇ 1.
  • multi-layer polyamic acid diaphragms can be formed by performing multiple interfacial polymerization reactions on the porous polyamic acid membrane surface, and the multi-layer polyamic acid diaphragms are beneficial to realize the surface membrane pore size through mutual superimposition. adjustable.
  • the concentration of the diamine aqueous solution is (0.01 ⁇ 10 -2 ) ⁇ (5 ⁇ 10 -2 ) g/mL, preferably (0.01 ⁇ 10 -2 ) ⁇ (2 ⁇ 10 -2 ) g/mL, more preferably (1 ⁇ 10 -2 ) to (2 ⁇ 10 - 2 ) g/mL.
  • the concentration of the acid chloride organic solution is (0.005 ⁇ 10 -2 ) ⁇ (1 ⁇ 10 -2 ) g/mL, preferably (0.05 ⁇ 10 -2 ) ⁇ (0.5 ⁇ 10 -2 ) g/mL, more preferably (0.1 ⁇ 10 -2 ) to (0.5 ⁇ 10 -2 ) g / mL.
  • the diamine monomer in the diamine aqueous solution may include, but is not limited to, m-phenylenediamine or p-phenylenediamine, preferably m-phenylenediamine.
  • the acid chloride monomer in the organic acid chloride solution may include, but is not limited to, pyromellitic acid chloride or bipyroyl tetracarboxylic acid chloride, preferably pyromellitic acid chloride.
  • the composite polyamic acid membrane is placed in the imidization reaction device, and it is subjected to imidization treatment in the vapor of the imidization reagent, wherein, the imidization reaction
  • the temperature ranges from 60°C to 250°C, preferably from 65°C to 120°C, more preferably from 65°C to 85°C.
  • the imidization reaction time is 2h-10h, preferably 4h-8h, more preferably 4h-6h.
  • the imidization reagent comprises an acid anhydride and a tertiary amine, wherein the volume ratio of the acid anhydride to the tertiary amine is 1:(0.7 ⁇ 1.5).
  • the imidization reagent of a suitable concentration can be obtained, and the concentration of the imidization reagent vapor thus formed is also kept within a suitable range, which is beneficial to Rapid progress of imidization reaction.
  • the acid anhydride may include, but is not limited to, one or more of acetic anhydride, propionic anhydride, succinic anhydride, benzoic anhydride, and phthalic anhydride.
  • the acid anhydride can be selected from one of acetic anhydride or propionic anhydride. More preferably, the acid anhydride can be selected from acetic anhydride.
  • the tertiary amine may include, but is not limited to, one or more of triethylamine, tributylamine, trimethylamine, dodecyldimethylamine, and hexadecyldimethylamine.
  • the tertiary amine can be selected from one or more of triethylamine, tributylamine and trimethylamine. More preferably, triethylamine can be selected as the tertiary amine.
  • step S06 it may also optionally include: drying the composite polyamic acid membrane obtained in the above step S04.
  • the drying process can be carried out by means known in the art, such as vacuum drying, airflow drying, spray drying, oven drying, and the like.
  • oven drying can be used.
  • the temperature of the drying treatment is 25°C-45°C, preferably 25°C-35°C.
  • the drying treatment time is 50 min to 70 min, preferably 50 min to 60 min.
  • the solvent on the surface of the composite polyamic acid membrane obtained in step S04 can be completely volatilized without affecting the structure and performance of the membrane.
  • step S02 may further include:
  • a polyamic acid membrane with a suitable porosity can be prepared through a phase inversion reaction, thereby facilitating the formation of a composite polyimide diaphragm.
  • the sum of the mass of dianhydride and diamine is 10%-30% ;
  • the molar ratio of diamine to dianhydride is 1:(1.005-1.01); the mass of polar solvent is 70%-90%; the mass of pore-forming agent is 1%-7%.
  • diamines may include, but are not limited to, 3,3'-dimethyl-4,4'-diaminodiphenylmethane and N,N'-bis(4-aminobenzene At least one of oxyphenyl) benzophenone tetraimides.
  • the diamine can be 3,3'-dimethyl-4,4'-diaminodiphenylmethane.
  • the dianhydride may include, but is not limited to, 3,3',4,4'-benzophenone tetracarboxylic dianhydride, 4,4'-triphenylene diether dianhydride, and At least one of tetraformic anhydride.
  • the dianhydride can be 3,3',4,4'-benzophenonetetracarboxylic dianhydride.
  • the pore-forming agent may include, but is not limited to, polyvinylpyrrolidone or polyethylene glycol.
  • the pore-forming agent can be selected polyethylene glycol. More preferably, the polyethylene glycol has a molecular weight of 200-400.
  • the polar solvent may include, but is not limited to, at least one of N-methylpyrrolidone, N,N-dimethylformamide and tetrahydrofuran.
  • tetrahydrofuran can be used as the polar solvent.
  • the polycondensation reaction is facilitated to obtain a polyamic acid solution.
  • a suitable pore-forming agent it is beneficial to form bubbles with a uniform shape and size in the polyamic acid solution, thereby facilitating the formation of the porous polyamic acid film described later, and the porous polyamic acid film is formed.
  • the shape and size of the stomata are relatively uniform.
  • the thickness of the polyamic acid casting solution coated on the substrate is 5 ⁇ m-200 ⁇ m, preferably 40 ⁇ m-200 ⁇ m, more preferably 40 ⁇ m-100 ⁇ m.
  • the coating thickness of the polyamic acid casting solution in an appropriate range, it is beneficial to obtain a porous polyamic acid membrane with a suitable thickness, and make the thickness of the composite polyimide diaphragm finally obtained Stay within the proper range.
  • the coagulation bath may include, but is not limited to, at least one of methanol, ethanol, n-butanol and water.
  • the coagulation bath can be water.
  • the temperature of the coagulation bath is 25°C-45°C, preferably 25-30°C.
  • the immersion time is 30 min to 180 min, preferably 30 min to 120 min, more preferably 60 min to 120 min.
  • the phase inversion reaction is facilitated, thereby obtaining a porous polyamic acid membrane with appropriate porosity and high tensile strength.
  • step S022 may further optionally include: vacuumizing and defoaming the polyamic acid solution obtained after adding the pore-forming agent to obtain a polyamic acid casting solution without bubbles.
  • the second aspect of the present application also provides a composite polyimide diaphragm, which is prepared by any one of the preparation methods in the first aspect of the present application.
  • the composite polyimide diaphragm includes a bottom base film 61, and at least one surface film 62 disposed on the bottom base film surface, wherein the bottom base film 61
  • the structure of the surface film 62 is relatively loose, and the structure of the surface film 62 is relatively dense.
  • the composite polyimide diaphragm of the present application is different from the single-layer integrated polyimide diaphragm in the prior art, and the pore size of the surface layer of the composite diaphragm can be regulated by controlling specific parameters in the corresponding preparation method.
  • the pore size of the surface membrane of the composite diaphragm By adjusting the pore size of the surface membrane of the composite diaphragm, a surface membrane with a suitable pore size can be obtained, and at the same time, the uniformity of the pore distribution of the surface membrane can be improved.
  • the composite polyimide diaphragm of the present application has a dense surface and a loose bottom structure, and the diaphragm has high porosity, air permeability and puncture strength, which can reduce the occurrence of micro-short circuits in the positive and negative electrodes of the secondary battery, and improve the efficiency of the secondary battery. Battery safety performance.
  • a secondary battery in one embodiment, includes a positive pole piece, a negative pole piece, an electrolyte, and a separator.
  • the isolation membrane adopts the composite polyimide diaphragm prepared by any one of the preparation methods of the first aspect of the application or any composite polyimide diaphragm of the second aspect of the application.
  • 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 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 NCM333), LiNi 0.5 Co 0.2 Mn 0.3 O 2 (also abbreviated as NCM523), LiNi 0.5 Co 0.25 Mn 0.25 O 2 (also abbreviated as NCM211), LiNi 0.6 Co 0.2 Mn 0.2 O 2 (also abbreviated as NCM622), LiNi 0.8 Co 0.1 Mn At least one of 0.1 O 2 (also abbreviated as NCM811), lithium nickel cobalt aluminum oxide (such as LiNi 0.85 Co 0.15 Al
  • lithium-containing phosphates with olivine structure may include but not limited to lithium iron phosphate (such as LiFePO 4 (also referred to as LFP)), composite material of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO 4 ), composite material of lithium manganese phosphate and carbon, manganese phosphate At least one of the composite materials of iron lithium, lithium iron manganese phosphate and carbon.
  • lithium iron phosphate such as LiFePO 4 (also referred to as LFP)
  • LiMnPO 4 lithium manganese phosphate
  • LiMnPO 4 lithium manganese phosphate
  • manganese phosphate At least one of the composite materials of iron lithium, lithium iron 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.
  • 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. 4 is an example of a secondary battery 5 with a square structure.
  • 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. 6 is an example of a battery module 5 .
  • 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 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. 9 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.
  • DMMDA 3,3'-dimethyl-4,4'-diaminodiphenylmethane
  • BTDA dry 3,3',4,4'-benzophenonetetracarboxylic dianhydride
  • the casting liquid is coated on the glass plate with a scraper, and the coating gap between the scraper and the glass plate is controlled to be 40um.
  • the scraped polyamic acid film was immersed in water at 30°C for phase inversion to form a coagulated film, and the immersion time was 120min.
  • aqueous m-phenylenediamine solution with a concentration of (2 ⁇ 10 -2 ) g/mL and a (0.1 ⁇ 10 -2 ) g/mL n-hexane solution of pyromellitic acid chloride were prepared. First, pour the m-phenylenediamine aqueous solution into the surface of the polyamic acid coagulation film and let it stand for 3 minutes, pour off the aqueous solution, blow it dry with an air knife, and then pour the pyromellitic chloride-n-hexane solution into the surface of the polyamic acid film and let it stand 10s to form a composite polyamic acid film, the reaction temperature of the above process is 25°C.
  • the composite polyamic acid membrane was dried in a drying oven at 25°C for 1 hour, and then the dried membrane was placed in the imidization reaction device shown in Figure 3 to obtain a composite polyimide diaphragm after reaction.
  • the steam temperature for controlling the imidization reaction is 120° C.
  • the imidization reagent is a mixed reagent of acetic anhydride and triethylamine with a volume ratio of 1:1
  • the imidization reaction time is 6 h.
  • the slurry was uniformly coated on a 12 ⁇ m thick positive electrode current collector aluminum foil, and then baked at 120° C. for 1 hour, followed by compaction and slitting in sequence to obtain a positive electrode sheet.
  • concentration of LiPF6 is 1mol/L.
  • the preparation process of the secondary battery is the same as that in Example 1, except that the interfacial polymerization reaction time is 20s.
  • the preparation process of the secondary battery is the same as that in Example 1, except that the interfacial polymerization reaction time is 40s.
  • the preparation process of the secondary battery is the same as in Example 1, except that the temperature of the interfacial polymerization reaction is 10°C.
  • the preparation process of the secondary battery is the same as that of Example 1, except that the temperature of the interfacial polymerization reaction is 45°C.
  • the preparation process of the secondary battery is the same as in Example 1, except that the concentration of the m-phenylenediamine aqueous solution is (0.01 ⁇ 10 -2 ) g/mL.
  • the preparation process of the secondary battery is the same as in Example 1, except that the concentration of the m-phenylenediamine aqueous solution is (5 ⁇ 10 ⁇ 2 ) g/mL.
  • the preparation process of the secondary battery is the same as in Example 1, except that the concentration of the pyromellitic chloride-n-hexane solution is (0.005 ⁇ 10 -2 ) g/mL.
  • the preparation process of the secondary battery is the same as in Example 1, except that the concentration of the pyromelliticoyl chloride n-hexane solution is (0.5 ⁇ 10 ⁇ 2 ) g/mL.
  • the preparation process of the secondary battery is the same as in Example 1, except that the concentration of the pyromelliticoyl chloride n-hexane solution is (1 ⁇ 10 ⁇ 2 ) g/mL.
  • the preparation process of the secondary battery is the same as that of Example 1, except that two interfacial polymerization reactions are performed.
  • the preparation process of the secondary battery is the same as that of Example 1, except that four interfacial polymerization reactions are performed.
  • the preparation process of the secondary battery is the same as in Example 1, except that the volume ratio of acetic anhydride and triethylamine in the imidization reagent is 1:0.7.
  • the preparation process of the secondary battery is the same as in Example 1, except that the volume ratio of acetic anhydride and triethylamine in the imidization reagent is 1:1.5.
  • the preparation process of the secondary battery is the same as in Example 1, except that the imidization treatment temperature is 60°C.
  • the preparation process of the secondary battery is the same as that in Example 1, except that the imidization treatment temperature is 250°C.
  • the preparation process of the secondary battery is the same as that in Example 1, except that the imidization treatment time is 2 hours.
  • the preparation process of the secondary battery is the same as that in Example 1, except that the imidization treatment time is 10 h.
  • the preparation process of the secondary battery is the same as in Example 1, except that the coating gap between the scraper and the glass plate is 5um.
  • the preparation process of the secondary battery is the same as in Example 1, except that the coating gap between the scraper and the glass plate is 200 um.
  • the preparation process of the secondary battery is the same as in Example 1, except that the temperature of the coagulation bath is 25°C.
  • the preparation process of the secondary battery is the same as in Example 1, except that the temperature of the coagulation bath is 45°C.
  • the preparation process of the secondary battery is the same as in Example 1, except that the immersion time is 30 minutes.
  • the preparation process of the secondary battery is the same as that in Example 1, except that the immersion time is 180 minutes.
  • the preparation process of the secondary battery is the same as that of Example 1, except that no interfacial polymerization reaction is performed.
  • the preparation process of the secondary battery is the same as in Example 1, except that the imidization treatment is conventional heating, that is, the dried composite polyamic acid film is treated at 60°C for 0.5h, at 100°C for 1h, at 200°C for 1h, and at 250°C 0.5h, 300°C for 0.5h, 400°C for 1h.
  • the preparation process of the secondary battery is the same as that of Example 1, except that the imidization treatment is conventional soaking, that is, the dried composite polyamic acid membrane is soaked in the imidization reagent solution at 25° C. for 6 hours.
  • the thickness of the diaphragm is a well-known meaning in the art, and can be tested by methods known in the art, such as using a micrometer (eg, Mitutoyo 293-100 type, with an accuracy of 0.1 ⁇ m) for testing.
  • a micrometer eg, Mitutoyo 293-100 type, with an accuracy of 0.1 ⁇ m
  • the diaphragm is cut into 100*15mm pieces with a knife die along the MD (length direction)/TD (width direction), and 5 parallel samples are made in each direction, and the high-speed iron tensile machine is used to pull at a speed of 100mm/min.
  • Tensile test take the average value of 5 samples in MD and TD as the tensile strength in MD and TD directions, respectively.
  • Tensile strength in MD direction maximum force value in MD direction/(thickness*width)/9.8
  • Tensile strength in TD direction maximum force value in TD direction/(thickness*width)/9.8
  • the puncture strength is tested according to the requirements of ASTM D4833-00e1. Using a high-speed iron tensile machine and a pogo pin with a diameter of 1mm, put the side of the diaphragm with the smaller aperture facing up to the needle, start the tensile machine to puncture at a speed of 100mm/min, read the value, the unit is N, measure 5 times The results are averaged.
  • the standard diaphragm air permeability test method is adopted.
  • the air permeability is defined as the time required for 100ml of nitrogen to pass through a certain area of the diaphragm under a certain pressure.
  • the air permeability value is tested by Wangyan digital air permeability tester.
  • Heat shrinkage rate in MD direction (MD direction dimension before heat-baking-MD direction dimension after heat-baking)/MD direction dimension before heat-baking*100%.
  • the battery core is placed in an environment with a temperature of 25°C, charging with a constant current of 1C to 3.65v, and then switching to constant voltage charging with a cut-off current of 0.05C, and discharging with a constant current of 1C to 2.5V.
  • a temperature of 25°C charging with a constant current of 1C to 3.65v
  • a cut-off current of 0.05C switching to constant voltage charging with a cut-off current of 0.05C
  • discharging with a constant current of 1C to 2.5V Use the above process to do cyclic charge and discharge test until the capacity decays to 80% of the initial value.
  • the present application is not limited to the above-mentioned embodiments.
  • the above-mentioned embodiments are merely examples, and within the scope of the technical solutions of the present application, embodiments that have substantially the same configuration as the technical idea and exert the same effects are included in the technical scope of the present application.
  • various modifications conceivable by those skilled in the art are added to the embodiments, and other forms constructed by combining some components in the embodiments are also included in the scope of the present application. .

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Abstract

本申请提供了一种复合聚酰亚胺隔膜及其制备方法、二次电池，复合聚酰亚胺隔膜的制备方法包括：提供多孔的聚酰胺酸膜；将二胺水溶液和酰氯有机溶液在所述多孔的聚酰胺酸膜面上进行界面聚合反应，得到复合聚酰胺酸隔膜；将复合聚酰胺酸隔膜置于亚胺化试剂的蒸汽中进行亚胺化处理，得到复合聚酰亚胺隔膜。本申请通过控制界面聚合反应的参数，能够得到表面致密、底部疏松且表面孔径可调控的复合聚酰胺酸隔膜。

Description

复合聚酰亚胺隔膜及其制备方法、二次电池
相关申请的交叉引用
本申请要求享有于2021年11月1日提交的名称为“复合聚酰亚胺隔膜及其制备方法、二次电池”的中国专利申请202111285297.7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
本申请涉及电池技术领域，尤其涉及一种复合聚酰亚胺隔膜及其制备方法、二次电池。
背景技术
电池隔膜作为电池的四大核心材料之一，起着隔离正负极的作用，使得电解液中的离子可以在正负极中自由穿行，但是电子不能穿过。隔膜的品质直接影响电池的充放电循环寿命、阻燃性能等安全性能指标。聚酰亚胺(PI)是一种综合性能良好的新型绝缘材料，具有优异的热稳定性和机械性能，可以在300℃以上的温度条件下长期使用，是理想的电池隔膜材料。但是，现有技术制备的聚酰亚胺隔膜经常容易引发二次电池的正负极发生微短路，从而导致电池爆炸、起火等安全事故。
发明内容
本申请是鉴于上述课题而进行的，其目的在于，提供一种复合聚酰亚胺隔膜及其制备方法、二次电池，旨在改善二次电池的安全性能。
为了达到上述目的，本申请第一方面提供了一种复合聚酰亚胺隔膜的制备方法，包括：
(a)提供多孔的聚酰胺酸膜；
(b)使二胺水溶液和酰氯有机溶液在多孔的聚酰胺酸膜面上进行界面聚合反应，得到复合聚酰胺酸隔膜；
(c)将复合聚酰胺酸隔膜置于亚胺化试剂的蒸汽中进行亚胺化反应，得到复合聚酰亚胺隔膜。
由此，本申请通过在多孔的聚酰胺酸膜面上进行界面聚合反应，能够得到复合结构的聚酰胺酸隔膜，之后将复合聚酰胺酸隔膜在亚胺化试剂的蒸汽中进行亚胺化处理，能够得到表面致密、底部疏松的复合聚酰亚胺隔膜。由于亚胺化处理是通过将复合聚酰胺酸隔膜置于亚胺化试剂的蒸汽中进行反应，而不是对隔膜直接进行高温加热，因而在亚胺化试剂的催化作用下，能够极大降低亚胺化反应的温度，由 此能够制备得到表面光滑、无裂纹的复合聚酰亚胺隔膜。此外，由于是将复合聚酰胺酸隔膜在亚胺化试剂的蒸汽中进行亚胺化，因而可以避免与液态的亚胺化试剂直接接触，由此亚胺化反应的速度不会过快，有利于获得孔隙分布均匀的复合聚酰亚胺隔膜。
在任意实施方式中，在步骤(b)中，控制界面聚合反应的时间、温度及次数，以使复合聚酰亚胺隔膜的表层膜孔径可调。通过调整界面聚合反应的时间、温度参数，以及通过增加界面聚合反应的次数而增加复合膜的层数，可以根据实际使用需求而将表层膜的孔径控制在合适的范围内。通过对界面聚合反应的参数进行调控，有利于形成致密的表层膜，由此可以提升隔膜的孔隙率和透气值，增强隔膜的穿刺强度，由此能够减少二次电池正负极发生微短路的情况，提升其安全性能。
在任意实施方式中，在步骤(b)中，界面聚合反应的时间为1s～120s，优选为10s～60s；和/或
界面聚合反应的温度为10℃～45℃，优选为25℃～45℃；和/或
界面聚合反应的次数为n≥1。
通过界面聚合反应的时间、温度及反应次数在一定范围内，能够实现对复合聚酰亚胺隔膜表层膜孔径的调控，有利于形成表面致密、底部疏松的复合聚酰亚胺隔膜。
在任意实施方式中，在步骤(b)中，二胺水溶液的浓度为(0.01×10 - 2)～(5×10 -2)g/mL，优选为(0.01×10 -2)～(2×10 -2)g/mL；和/或
酰氯有机溶液的浓度为(0.005×10 -2)～(1×10 -2)g/mL，优选为(0.05×10 - 2)～(0.5×10 -2)g/mL。
在任意实施方式中，在步骤(b)中，二胺水溶液的浓度为(0.01×10 - 2)～(5×10 -2)g/mL，优选为(0.01×10 -2)～(2×10 -2)g/mL；和/或酰氯有机溶液的浓度为(0.005×10 -2)～(1×10 -2)g/mL，优选为(0.05×10 -2)～(0.5×10 -2)g/mL。
通过将二胺水溶液和酰氯有机溶液的浓度控制在合适的范围内，有利于界面聚合反应的发生。
在任意实施方式中，在步骤(b)中，二胺水溶液中的二胺单体包含间苯二胺或对苯二胺；和/或
酰氯有机溶液中的酰氯单体包含均苯四甲酰氯或联苯四酰氯。
在任意实施方式中，在步骤(c)中，亚胺化反应的温度为60℃～250℃，优选为65℃～120℃；和/或
亚胺化反应的时间为2h～10h，优选为4h～8h。
通过将亚胺化反应的温度和时间控制在合适范围内，有利于形成亚胺化试剂的蒸汽催化氛围，并有利于将亚胺化反应的速度控制在合适的范围，由此能够制备得到表面光滑、无裂纹且孔隙率较高的复合聚酰亚胺隔膜。
在任意实施方式中，在步骤(c)中，亚胺化试剂包含酸酐和叔胺，其中，所述酸酐与所述叔胺的体积比为1:(0.7～1.5)。
通过将酸酐与叔胺的体积比控制在合适范围内，能够得到适宜浓度的亚胺化 试剂，有利于提升亚胺化反应的效率。
在任意实施方式中，酸酐包含乙酸酐、丙酸酐、丁二酸酐、苯甲酸酐及邻苯二甲酸酐中的一种或几种；和/或
叔胺包含三乙胺、三丁胺、三甲胺、十二烷基二甲基胺及十六烷基二甲基胺中的一种或几种。
在任意实施方式中，方法还包括：将步骤(b)得到的复合聚酰胺酸隔膜进行干燥处理，其中，
干燥处理的温度为25℃～45℃，优选为25℃～35℃；和/或
干燥处理的时间为50min～70min，优选为50min～60min。
在任意实施方式中，步骤(a)包括：
(a1)使二酐和二胺在极性溶剂中进行缩聚反应，之后加入成孔剂并混匀，得到聚酰胺酸铸膜液；
(a2)将聚酰胺酸铸膜液涂布于基板上，然后浸没在凝固浴中进行相转化反应，得到多孔的聚酰胺酸膜。
通过相转化反应，能够得到孔隙率较高的聚酰胺酸膜。
在任意实施方式中，在步骤(a1)中，以二酐、二胺、极性溶剂及成孔剂的总质量为100％计，二酐与二胺两者的质量之和为10％～30％；优选的，二胺与二酐的摩尔比为1:(1.005～1.01)；极性溶剂的质量为70％～90％；成孔剂的质量为1％～7％。
通过将二酐、二胺、极性溶剂及成孔剂的质量比控制在合适的范围内，有利于获得孔隙率合适的聚酰胺酸铸膜液。
在任意实施方式中，二胺包含3,3’-二甲基-4,4’-二胺基二苯甲烷和N,N'-二(4-氨基苯氧基苯基)二苯酮四酰亚胺中的至少一种；和/或二酐包含3,3’,4,4’-二苯酮四甲酸二酐、4,4'-三苯二醚二酐和均苯四甲酸酐中的至少一种；和/或成孔剂包含聚乙烯吡咯烷酮或聚乙二醇；优选的，聚乙二醇的分子量为200～400；和/或极性溶剂包含N-甲基吡咯烷酮、N,N-二甲基甲酰胺及四氢呋喃中的至少一种。
通过选取合适的二胺、二酐及极性溶剂，有利于缩聚反应的发生而获得聚酰胺酸溶液；通过选取合适的成孔剂，有利于在聚酰胺酸溶液中形成形状和大小较均匀的气泡，由此有利于后续形成的多孔的聚酰胺酸膜所含有的气孔，其形状和大小都较均匀。
在任意实施方式中，在步骤(a2)中，聚酰胺酸铸膜液涂布于基板上的厚度为5μm～200μm，优选为40μm～200μm。
通过将聚酰胺酸铸膜液的涂布厚度控制在合适范围内，有利于获得厚度适当的多孔的聚酰胺酸膜，并使最终获得的复合聚酰亚胺隔膜的厚度保持在合适的范围。
在任意实施方式中，在步骤(a2)中，凝固浴包含甲醇、乙醇、正丁醇及水中的至少一种；和/或凝固浴的温度为25℃～45℃，优选为25～30℃；和/或浸没的时间为30min～180min，优选为30min～120min。
通过将凝固浴的温度和时间控制在合适范围内，有利于相转化反应的进行，并获得合适孔隙率的多孔的聚酰胺酸膜。
本申请的第二方面还提供一种复合聚酰亚胺隔膜，采用本申请第一方面所述的制备方法制得。
在任意实施方式中，复合聚酰亚胺隔膜包括底层基膜，和设置于底层基膜膜面上的至少一层表层膜。
由此，通过利用本申请的制备方法，能够得到一种具备复合结构的复合聚酰亚胺隔膜，不同于现有技术中的一体化聚酰亚胺隔膜，本申请中的复合聚酰亚胺隔膜的表层膜的孔径可以进行调控。通过对表层膜孔径的调控，能够得到孔隙分布均匀的复合聚酰亚胺隔膜，同时可以提升隔膜的孔隙率和透气度，增强隔膜的穿刺强度，减少二次电池正负极发生微短路的情况，提升二次电池的安全性能。
本申请的第三方面提供一种二次电池，包括根据本申请第一方面的制备方法制得的复合聚酰亚胺隔膜或本申请第二方面的复合聚酰亚胺隔膜。
本申请的第四方面提供一种电池模块，包括本申请的第三方面的二次电池。
本申请的第五方面提供一种电池包，包括本申请的第四方面的电池模块。
本申请的第六方面提供一种用电装置，包括选自本申请的第三方面的二次电池、本申请的第四方面的电池模块或本申请的第五方面的电池包中的至少一种。
附图说明
图1为本申请一实施方式的复合聚酰亚胺隔膜的结构示意图。
图2本申请一实施方式的复合聚酰亚胺隔膜的表层膜的局部放大图。
图3本申请一实施方式的亚胺化反应装置的结构示意图。
图4本申请一实施方式的二次电池的示意图。
图5图5所示的本申请一实施方式的二次电池的分解图。
图6本申请一实施方式的电池模块的示意图。
图7本申请一实施方式的电池包的示意图。
图8图7示的本申请一实施方式的电池包的分解图。
图9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；6复合聚酰亚胺隔膜；7复合聚酰亚胺隔膜的表层膜局部放大图；8亚胺化反应装置。51壳体；52电极组件；53顶盖组件；61底层基膜；62表层膜；81亚胺化试剂。
621表层膜局部放大图。
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聚酰亚胺隔膜及其制备方法、二次电池、电池模块、电池包和电学装置的实施方式。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)。
发明人在研究过程中发现，现有技术制备的聚酰亚胺隔膜，在亚胺化处理的过程中，通常需要对隔膜进行高温加热处理，由于反应温度较高，因而极易造成隔膜卷曲变形、表面开裂的问题。此外，现有技术制备的聚酰亚胺隔膜，通常为单层的一体化结构，在制备过程中，无法根据二次电池的实际使用需求而对隔膜的表面孔径进行调控，由此制备得到的隔膜表面孔径通常较大，容易引发二次电池的正负极发生内短路的问题。
针对上述技术问题，本申请提出了一种聚酰亚胺隔膜的制备方法，该方法通 过采用界面聚合反应能够得到一种复合结构的聚酰亚胺隔膜，该隔膜的表面致密、底部疏松，而且隔膜的表面孔径及表面致密程度可以通过控制界面聚合反应的参数而实现调控。此外，在亚胺化处理的过程中，该方法通过将隔膜置于亚胺化试剂的蒸汽中进行反应，而不是对隔膜直接进行高温加热，因而在亚胺化试剂的催化作用下，能够极大降低亚胺化反应的温度，由此能够制备得到表面光滑、无裂纹的复合聚酰亚胺隔膜。
复合聚酰亚胺隔膜
本申请的一个实施方式中，本申请第一方面提供了一种复合聚酰亚胺隔膜的制备方法，包括：
S02、提供多孔的聚酰胺酸膜；
S04、使二胺水溶液和酰氯有机溶液在多孔的聚酰胺酸膜面上进行界面聚合反应，得到复合聚酰胺酸隔膜；
S06、将复合聚酰胺酸隔膜置于亚胺化试剂的蒸汽中进行亚胺化反应，得到复合聚酰亚胺隔膜。
本申请通过将二胺水溶液和酰氯有机溶液在多孔的聚酰胺酸膜面上进行界面聚合反应，能够得到复合聚酰胺酸隔膜，然后将该复合聚酰胺酸隔膜置于亚胺化试剂的蒸汽中进行亚胺化反应，能够得到复合结构的聚酰亚胺隔膜。
在本申请的制备方法中，由于采用了界面聚合的方法，因而能够在多孔的聚酰胺酸膜上形成多层结构的复合膜，之后再进行亚胺化处理，即可得到不同于现有技术中一体化单层隔膜的具备复合结构的聚酰亚胺隔膜。此外，本申请制备方法中，由于亚胺化处理是通过将复合聚酰胺酸隔膜置于亚胺化试剂的蒸汽中进行反应，而不是对隔膜直接进行高温加热，因而在亚胺化试剂的催化作用下，能够极大降低亚胺化反应的温度，由此能够制备得到表面光滑、无裂纹的复合聚酰亚胺隔膜；而且由于复合聚酰胺酸隔膜是在亚胺化试剂的蒸汽中进行亚胺化，因而可以避免其与液态的亚胺化试剂直接接触，由此亚胺化反应的速度不会过快，有利于获得孔隙分布均匀的复合聚酰亚胺隔膜。
在一些实施方式中，上述步骤S04中，控制界面聚合反应的时间、温度及次数，以使复合聚酰亚胺隔膜的表层膜孔径可调。
本申请制备方法中，通过调整界面聚合反应的时间、温度参数，以及通过增加界面聚合反应的次数而增加复合膜的层数，可以根据实际使用需求而将表层膜的孔径控制在合适的范围内。通过对界面聚合反应的参数进行调控，有利于形成致密的表层膜，由此可以提升隔膜的孔隙率和透气值，增强隔膜的穿刺强度，减少二次电池正负极发生微短路的情况，提升二次电池的安全性能。
在一些实施方式中，上述步骤S04中，界面聚合反应的时间为1s～120s，优选为10s～60s，更优选为10s～20s。本申请制备方法中，通过将界面聚合反应的时间控制在合适范围，有利于形成薄厚适宜且表面孔径较小的聚酰胺酸隔膜。
在一些实施方式中，上述步骤S04中，界面聚合反应的温度为10℃～45℃，优选为25℃～45℃；更优选为25℃～35℃。本申请制备方法中，通过将界面聚合反应 的温度控制在合适范围，有利于提升界面聚合反应的速度，使反应进行得更加完全，从而形成表面致密的聚酰胺酸隔膜。
在一些实施方式中，上述步骤S04中，界面聚合反应的次数为n≥1。本申请制备方法中，通过在多孔的聚酰胺酸膜面上进行多次界面聚合反应，能够形成多层聚酰胺酸隔膜，多层聚酰胺酸隔膜通过相互间的叠加作用有利于实现表面膜孔径的可调控。
在一些实施方式中，上述步骤S04中，二胺水溶液的浓度为(0.01×10 -2)～(5×10 -2)g/mL，优选为(0.01×10 -2)～(2×10 -2)g/mL，更优选为(1×10 -2)～(2×10 - 2)g/mL。
在一些实施方式中，上述步骤S04中，酰氯有机溶液的浓度为(0.005×10 - 2)～(1×10 -2)g/mL，优选为(0.05×10 -2)～(0.5×10 -2)g/mL，更优选为(0.1×10 - 2)～(0.5×10 -2)g/mL。
本申请制备方法中，通过将二胺水溶液和酰氯有机溶液的浓度控制在合适的范围内，有利于提升界面聚合反应的速度，使反应进行得更加完全，从而形成表面致密的聚酰胺酸隔膜。
在一些实施方式中，上述步骤S04中，二胺水溶液中的二胺单体可以但不限于包括间苯二胺或对苯二胺，优选为间苯二胺。
在一些实施方式中，上述步骤S04中，酰氯有机溶液中的酰氯单体可以但不限于包括均苯四甲酰氯或联苯四酰氯，优选为均苯四甲酰氯。
在一些实施方式中，如图3所示，将复合聚酰胺酸隔膜置于亚胺化反应装置中，并使其在亚胺化试剂的蒸汽中进行亚胺化处理，其中，亚胺化反应的温度为60℃～250℃，优选为65℃～120℃，更优选为65℃～85℃。
本申请制备方法中，通过将亚胺化反应的温度控制在合适范围，有利于形成亚胺化试剂的蒸汽催化氛围，并有利于将亚胺化反应的速度控制在合适的范围，不会使亚胺化反应的速度太快，由此有利于获得孔隙分布均匀的复合聚酰胺酸隔膜。
在一些实施方式中，上述步骤S06中，亚胺化反应的时间为2h～10h，优选为4h～8h，更优选为4h～6h。
本申请制备方法中，通过将亚胺化反应的时间控制在合适范围，有利于获得表面光滑、无裂纹且孔隙率较高的复合聚酰亚胺隔膜。
在一些实施方式中，上述步骤S06中，亚胺化试剂包含酸酐和叔胺，其中，酸酐与叔胺的体积比为1:(0.7～1.5)。
本申请制备方法中，通过将酸酐与叔胺的体积比控制在合适范围内，能够得到适宜浓度的亚胺化试剂，由此形成的亚胺化试剂蒸汽的浓度也保持在合适范围，有利于亚胺化反应的快速进行。
在一些实施方式中，酸酐可以但不限于包括乙酸酐、丙酸酐、丁二酸酐、苯甲酸酐及邻苯二甲酸酐中的一种或几种。
优选的，酸酐可以选自乙酸酐或丙酸酐中的一种。更优选的，酸酐可以选用乙酸酐。
在一些实施方式中，叔胺可以但不限于包括三乙胺、三丁胺、三甲胺、十二烷基二甲基胺及十六烷基二甲基胺中的一种或几种。
优选的，叔胺可以选自三乙胺、三丁胺及三甲胺中的一种或几种。更优选的，叔胺可以选用三乙胺。
在一些实施方式中，上述制备方法中，在步骤S06之前还可选的包括：将上述步骤S04得到的复合聚酰胺酸隔膜进行干燥处理。
在一些实施方式中，干燥处理可以采用本领域已知的方式进行干燥，如真空干燥、气流干燥、喷雾干燥、烘干干燥等。优选的，可以采用烘干干燥。
在一些实施方式中，干燥处理的温度为25℃～45℃，优选为25℃～35℃。
在一些实施方式中，干燥处理的时间为50min～70min，优选为50min～60min。
本申请制备方法中，通过将干燥处理的温度和时间控制在合适范围内，既可以使步骤S04得到的复合聚酰胺酸隔膜表面的溶剂完全挥发，又不会影响到隔膜的结构和性能。
在一些实施方式中，上述步骤S02可以进一步包括：
S022、使二酐和二胺在极性溶剂中进行缩聚反应，之后加入成孔剂并混匀，得到聚酰胺酸铸膜液；
S024、将聚酰胺酸铸膜液涂布于基板上，然后浸没在凝固浴中进行相转化反应，得到多孔的聚酰胺酸膜。
本申请制备方法中，通过相转化反应能够制备得到孔隙率合适的聚酰胺酸膜，从而有利于形成复合的聚酰亚胺隔膜。
在一些实施方式中，上述步骤S022中，以二酐、二胺、极性溶剂及成孔剂的总质量为100％计，二酐与二胺两者的质量之和为10％～30％；优选的，二胺与二酐的摩尔比为1:(1.005～1.01)；极性溶剂的质量为70％～90％；成孔剂的质量为1％～7％。
本申请制备方法中，通过将二酐、二胺、极性溶剂及成孔剂的质量比控制在合适的范围内，有利于缩聚反应的发生，并有利于获得孔隙率合适的聚酰胺酸铸膜液。
在一些实施方式中，上述步骤S022中，二胺可以但不限于包括3,3’-二甲基-4,4’-二胺基二苯甲烷和N,N'-二(4-氨基苯氧基苯基)二苯酮四酰亚胺中的至少一种。优选的，二胺可选用3,3’-二甲基-4,4’-二胺基二苯甲烷。
在一些实施方式中，上述步骤S022中，二酐可以但不限于包括3,3’,4,4’-二苯酮四甲酸二酐、4,4'-三苯二醚二酐和均苯四甲酸酐中的至少一种。优选的，二酐可选用3,3’,4,4’-二苯酮四甲酸二酐。
在一些实施方式中，上述步骤S022中，成孔剂可以但不限于包括聚乙烯吡咯烷酮或聚乙二醇。
优选的，成孔剂可选用聚乙二醇。更优选的，聚乙二醇的分子量为200～400。
在一些实施方式中，上述步骤S022中，极性溶剂可以但不限于包括N-甲基吡咯烷酮、N,N-二甲基甲酰胺及四氢呋喃中的至少一种。优选的，极性溶剂可选用四氢呋喃。
本申请制备方法中，通过选取合适的二胺、二酐及极性溶剂，有利于缩聚反应的发生，从而获得聚酰胺酸溶液。通过选取合适的成孔剂，有利于在聚酰胺酸溶液中形成形状和大小较均匀的气泡，由此有利于形成后续所述的多孔的聚酰胺酸膜，而且该多孔的聚酰胺酸膜所含有气孔的形状和大小都较均匀。
在一些实施方式中，上述步骤S024中，聚酰胺酸铸膜液涂布于基板上的厚度为5μm～200μm，优选为40μm～200μm，更优选为40μm～100μm。
本申请制备方法中，通过将聚酰胺酸铸膜液的涂布厚度控制在合适范围内，有利于获得适宜厚度的多孔的聚酰胺酸膜，并使最终获得的复合聚酰亚胺隔膜的厚度保持在合适的范围。
在一些实施方式中，上述步骤S024中，凝固浴可以但不限于包括甲醇、乙醇、正丁醇及水中的至少一种。优选的，凝固浴可选用水。
在一些实施方式中，上述步骤S024中，凝固浴的温度为25℃～45℃，优选为25～30℃。
在一些实施方式中，上述步骤S024中，浸没的时间为30min～180min，优选为30min～120min，更优选为60min～120min。
本申请制备方法中，通过将凝固浴的温度和时间控制在合适范围内，有利于相转化反应的进行，从而获得孔隙率合适且拉伸强度较高的多孔的聚酰胺酸膜。
在一些实施方式中，步骤S022中还进一步可选的包括：将加入成孔剂之后得到的聚酰胺酸溶液进行抽真空脱泡处理，得到无气泡的聚酰胺酸铸膜液。
本申请第二方面还提供了一种复合聚酰亚胺隔膜，采用本申请第一方面的任意一种制备方法制得。
在一些实施方式中，如图1和图2所示，复合聚酰亚胺隔膜包括底层基膜61，和设置于底层基膜膜面上的至少一层表层膜62，其中，底层基膜61的结构较疏松，表层膜62的结构较致密。
本申请的复合聚酰亚胺隔膜，不同于现有技术中的单层一体化聚酰亚胺隔膜，该复合隔膜表层膜的孔径可以通过控制相应制备方法中的特定参数进行调控。通过对复合隔膜表层膜的孔径进行调控，能够得到合适孔径的表层膜，同时可以提升表层膜孔隙分布的均匀性。本申请的复合聚酰亚胺隔膜具备表面致密、底部疏松的结构，隔膜的孔隙率、透气度及穿刺强度较高，由此可以减少二次电池正负极发生微短路的情况，提升二次电池的安全性能。
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。
二次电池
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。其中，隔离膜采用本申请第一方面的任 意一种制备方法制得的复合聚酰亚胺隔膜或本申请第二方面的任意一种复合聚酰亚胺隔膜。
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NCM333)、LiNi 0.5Co 0.2Mn 0.3O 2(也可以简称为NCM523)、LiNi 0.5Co 0.25Mn 0.25O 2(也可以简称为NCM211)、LiNi 0.6Co 0.2Mn 0.2O 2(也可以简称为NCM622)、LiNi 0.8Co 0.1Mn 0.1O 2(也可以简称为NCM811)、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。
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4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5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6作为一个示例的电池模块5。照图6，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7和图8作为一个示例的电池包1。参照图7和图8，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9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
复合聚酰亚胺隔膜的制备
在温度为0℃，氮气的气氛下，将7.69g干燥的3,3’-二甲基-4,4’-二胺基二苯甲烷(DMMDA)加入到装有78g溶剂的三口烧瓶中，进行机械搅拌直到DMMDA溶解，然后再加入12.31g干燥的3,3’,4,4’-二苯酮四甲酸二酐(BTDA)继续进行机械搅拌反应12h，最后向上述反应物中加入2g的PEG(200)搅拌3h，将上述反应得到的溶液进行真空静置脱泡，得到聚酰胺酸铸膜液。
用刮刀将铸膜液在玻璃板上进行涂布，控制刮刀与玻璃板之间的涂布间隙为40um。将刮制的聚酰胺酸膜浸没在30℃的水中进行相转化形成凝固膜，浸没时间为120min。
配置浓度为(2×10 -2)g/mL的间苯二胺水溶液和(0.1×10 -2)g/mL的均苯四甲酰氯正己烷溶液。先将间苯二胺水溶液倒入聚酰胺酸凝固膜表面静置3min，将水溶液倒掉，用风刀吹干，再将均苯四甲酰氯正己烷溶液倒入上述聚酰胺酸膜表面静 置10s，形成复合聚酰胺酸膜，上述过程的反应温度为25℃。
将复合聚酰胺酸膜在25℃的干燥箱中干燥1h，然后将干燥后的膜片置于图3所示的亚胺化反应装置中，反应后得到复合聚酰亚胺隔膜。其中，控制亚胺化反应的蒸汽温度为120℃，亚胺化试剂为乙酸酐和三乙胺按体积比为1:1的混合试剂，亚胺化反应时间为6h。
正极片的制备
将正极活性材料LiNi 0.8Co 0.1Mn 0.1O 2、导电剂乙炔黑、粘结剂PVDF按质量比96:2:2进行混合，加入溶剂NMP搅拌至体系呈均一状，获得正极浆料；将正极浆料均匀涂覆在12μm厚的正极集流体铝箔上，然后在120℃下烘烤1h后，再依次经过压实、分切，获得正极片。
负极片的制备
将负极活性材料石墨、导电剂乙炔黑、增稠剂CMC、粘结剂SBR按照质量比97:1:1:1混合，加入溶剂去离子水，在真空搅拌机作用下搅拌至稳定均一，获得负极浆料，将负极浆料均匀涂覆于负极集流体铜箔上，经干燥、冷压后，得到负极片。
电解液的制备
在干燥房中，将碳酸乙烯酯(EC)、碳酸丙烯酯(PC)、碳酸二乙酯(DEC)按重量比EC:PC:DEC＝1:1:1混合，得到混合溶剂，然后将LiPF6均匀溶解在混合溶剂中，得到非水电解液。其中LiPF6的浓度为1mo l/L。
二次电池的制备
将正极片、复合聚酰亚胺隔膜、负极片依次叠片制备电芯，将复合聚酰亚胺隔膜与负极片贴合，再装入铝箔包装袋，然后依次注入电解液、封装，获得容量为1Ah的锂金属电池。
实施例2
二次电池的制备过程同实施例1，区别在于：界面聚合反应的时间为20s。
实施例3
二次电池的制备过程同实施例1，区别在于：界面聚合反应的时间为40s。
实施例4
二次电池的制备过程同实施例1，区别在于：界面聚合反应的温度为10℃。
实施例5
二次电池的制备过程同实施例1，区别在于：界面聚合反应的温度为45℃。
实施例6
二次电池的制备过程同实施例1，区别在于：间苯二胺水溶液的浓度为(0.01×10 -2)g/mL。
实施例7
二次电池的制备过程同实施例1，区别在于：间苯二胺水溶液的浓度为(5 ×10 -2)g/mL。
实施例8
二次电池的制备过程同实施例1，区别在于：均苯四甲酰氯正己烷溶液的浓度为(0.005×10 -2)g/mL。
实施例9
二次电池的制备过程同实施例1，区别在于：均苯四甲酰氯正己烷溶液的浓度为(0.5×10 -2)g/mL。
实施例10
二次电池的制备过程同实施例1，区别在于：均苯四甲酰氯正己烷溶液的浓度为(1×10 -2)g/mL。
实施例11
二次电池的制备过程同实施例1，区别在于：进行2次界面聚合反应。
实施例12
二次电池的制备过程同实施例1，区别在于：进行4次界面聚合反应。
实施例13
二次电池的制备过程同实施例1，区别在于：亚胺化试剂中乙酸酐和三乙胺的体积比为1:0.7。
实施例14
二次电池的制备过程同实施例1，区别在于：亚胺化试剂中乙酸酐和三乙胺的体积比为1:1.5。
实施例15
二次电池的制备过程同实施例1，区别在于：亚胺化处理的温度为60℃。
实施例16
二次电池的制备过程同实施例1，区别在于：亚胺化处理的温度为250℃。
实施例17
二次电池的制备过程同实施例1，区别在于：亚胺化处理的时间为2h。
实施例18
二次电池的制备过程同实施例1，区别在于：亚胺化处理的时间为10h。
实施例19
二次电池的制备过程同实施例1，区别在于：刮刀与玻璃板之间的涂布间隙为5um。
实施例20
二次电池的制备过程同实施例1，区别在于：刮刀与玻璃板之间的涂布间隙为200um。
实施例21
二次电池的制备过程同实施例1，区别在于：凝固浴的温度为25℃。
实施例22
二次电池的制备过程同实施例1，区别在于：凝固浴的温度为45℃。
实施例23
二次电池的制备过程同实施例1，区别在于：浸没的时间为30min。
实施例24
二次电池的制备过程同实施例1，区别在于：浸没的时间为180min。
对比例1
二次电池的制备过程同实施例1，区别在于：不进行界面聚合反应。
对比例2
二次电池的制备过程同实施例1，区别在于：亚胺化处理为常规加热，即将干燥后的复合聚酰胺酸膜60℃处理0.5h，100℃处理1h，200℃处理1h，250℃处理0.5h，300℃处理0.5h，400℃处理1h。
对比例3
二次电池的制备过程同实施例1，区别在于：亚胺化处理为常规浸泡，即将干燥后的复合聚酰胺酸膜在25℃下浸泡于亚胺化试剂的溶液中6h。
测试部分
复合聚酰亚胺隔膜厚度测试
隔膜厚度为本领域公知的含义，可采用本领域已知的方法测试例，如采用万分尺(例如Mitutoyo293-100型，精度为0.1μm)进行测试。
复合聚酰亚胺隔膜拉伸强度测试
先将隔膜沿MD(长度方向)/TD(宽度方向)用刀模分别冲切成100*15mm的片料，每个方向做5个平行样，用高铁拉力机以运行速度100mm/min进行拉伸测试，取5个样品在MD和TD上的平均值分别作为MD和TD方向上的拉伸强度。
MD方向的拉伸强度＝MD方向的最大力值/(厚度*宽度)/9.8
TD方向的拉伸强度＝TD方向的最大力值/(厚度*宽度)/9.8
复合聚酰亚胺隔膜穿刺强度测试
穿刺强度按ASTM D4833-00e1的要求进行测试。采用高铁拉力机和直径为1mm的弹簧针，将隔膜孔径较小的一面朝上正对针头，启用拉力机以100mm/min的速度进行刺穿，读取数值，单位为N，测量5次结果取均值。
复合聚酰亚胺隔膜透气值测试
采用标准的隔膜透气度测试方法，透气度定义为100ml氮气在一定压力下通过一定面积隔膜需要的时间，透气值使用王研式数字型透气度测试仪进行测试。
复合聚酰亚胺隔膜孔隙率测试
取15cm*15cm的块状隔膜样品，采用称重法测试孔隙率，测试5个样品的平均值作为孔隙率，具体计算公式为：
隔膜孔隙率＝1-隔膜质量/(密度*体积)＝1-面密度/(密度*厚度)，其中，聚酰亚胺隔膜的密度为0.95g/cm 3。
复合聚酰亚胺隔膜的表层膜孔径测试
采用SEM拍摄隔膜表面和断面的形貌，进而测量出隔膜的孔径。
复合聚酰亚胺隔膜热收缩率测试
用刀膜将隔膜冲切成100mm×50mm的四方形片料，将片料置于150℃的烘箱中，保温30min，测试TD和MD方向的长度变化，最后取5个样品分别在MD和TD方向上的平均值作为各自的热收缩率。
MD方向上的热收缩率＝(热烘前MD方向尺寸-热烘后MD方向尺寸)/热烘前MD方向尺寸*100％。
TD方向上的热收缩率＝(热烘前TD方向尺寸-热烘后TD方向尺寸)/热烘前TD方向尺寸*100％
二次电池循环性能测试
用常规的充放电机设备，电芯置于温度为25℃的环境中，充电用1C恒流充电至3.65v，再转恒压充电截止电流0.05C，放电用1C恒流放电至2.5V，采用上述流程做循环充放电测试，直至容量衰减至初始的80％。
上述实施例1～24、对比例1～3的复合聚酰亚胺隔膜的相关参数如下表1所示。
表1：实施例1～24与对比例1～3的参数结果
Figure PCTCN2022123066-appb-000001
另外，将上述实施例1～24和对比例1～3中得到的复合聚酰亚胺隔膜及其所 制备的二次电池，进行性能测试，测试结果如下表2所示。
表2：实施例1～24与对比例1～3的性能测试结果。
Figure PCTCN2022123066-appb-000002
由实施例1～24与对比例1～3对比可知，采用本申请的复合聚酰亚胺隔膜，二次电池的循环性能得到了提升。
由实施例1～12与对比例1的结果可知，通过界面聚合反应，可以得到表层膜孔径可调的隔膜，而且界面聚合反应的时间、温度、反应次数及反应溶液的浓度均会对隔膜表层膜孔径的大小产生影响，由此可以通过控制界面聚合反应的参数而得到实际应用中所需要的孔径。
另外，与对比例1相比，实施例1～12中隔膜的穿刺强度明显高于对比例1，隔膜150℃的热收缩率明显低于对比例1，由此本申请通过界面聚合反应制备的复合聚酰亚胺隔膜具备优异的性能。
由实施例13～18与对比例2～3的结果可知，与常规的加热及浸泡处理相比，本申请通过将隔膜置于亚胺化蒸汽中进行亚胺化处理的方法反应速率更快且所得到的隔膜孔隙率更高，整体性能更佳。
由实施例19～24与对比例1～3的结果可知，相转化反应中，刮刀与玻璃板之间的涂布间隙对隔膜的穿刺强度影响较大，这是由于该涂布间隙会极大影响隔膜 中底层基膜的厚度。
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 (20)

  1. 一种复合聚酰亚胺隔膜的制备方法，包括：
    (a)提供多孔的聚酰胺酸膜；
    (b)使二胺水溶液和酰氯有机溶液在所述多孔的聚酰胺酸膜面上进行界面聚合反应，得到复合聚酰胺酸隔膜；
    (c)将所述复合聚酰胺酸隔膜置于亚胺化试剂的蒸汽中进行亚胺化反应，得到复合聚酰亚胺隔膜。
  2. 如权利要求1所述的制备方法，其中，在所述步骤(b)中，控制界面聚合反应的时间、温度及次数，以使所述复合聚酰亚胺隔膜的表层膜孔径可调。
  3. 如权利要求2所述的制备方法，其中，在所述步骤(b)中，所述界面聚合反应的时间为1s～120s，优选为10s～60s；和/或
    所述界面聚合反应的温度为10℃～45℃，优选为25℃～45℃；和/或
    所述界面聚合反应的次数为n≥1。
  4. 如权利要求2所述的制备方法，其中，在所述步骤(b)中，所述二胺水溶液的浓度为(0.01×10 -2)～(5×10 -2)g/mL，优选为(0.01×10 -2)～(2×10 -2)g/mL；和/或
    所述酰氯有机溶液的浓度为(0.005×10 -2)～(1×10 -2)g/mL，优选为(0.05×10 - 2)～(0.5×10 -2)g/mL。
  5. 如权利要求2所述的制备方法，其中，在所述步骤(b)中，所述二胺水溶液中的二胺单体包含间苯二胺或对苯二胺；和/或
    所述酰氯有机溶液中的酰氯单体包含均苯四甲酰氯或联苯四酰氯。
  6. 如权利要求2所述的制备方法，其中，在所述步骤(c)中，所述亚胺化反应的温度为60℃～250℃，优选为65℃～120℃；和/或
    所述亚胺化反应的时间为2h～10h，优选为4h～8h。
  7. 如权利要求2所述的制备方法，其中，在所述步骤(c)中，所述亚胺化试剂 包含酸酐和叔胺，
    其中，所述酸酐与所述叔胺的体积比为1:(0.7～1.5)。
  8. 如权利要求7所述的制备方法，其中，所述酸酐包含乙酸酐、丙酸酐、丁二酸酐、苯甲酸酐及邻苯二甲酸酐中的一种或几种；和/或
    所述叔胺包含三乙胺、三丁胺、三甲胺、十二烷基二甲基胺及十六烷基二甲基胺中的一种或几种。
  9. 如权利要求2所述的制备方法，其中，所述方法还包括将步骤(b)得到的复合聚酰胺酸隔膜进行干燥处理，其中，
    所述干燥处理的温度为25℃～45℃，优选为25℃～35℃；和/或
    所述干燥处理的时间为50min～70min，优选为50min～60min。
  10. 如权利要求2所述的制备方法，其中，所述步骤(a)包括：
    (a 1)使二酐和二胺在极性溶剂中进行缩聚反应，之后加入成孔剂并混匀，得到聚酰胺酸铸膜液；
    (a 2)将所述聚酰胺酸铸膜液涂布于基板上，然后浸没在凝固浴中进行相转化反应，得到所述多孔的聚酰胺酸膜。
  11. 如权利要求10所述的制备方法，其中，在所述步骤(a 1)中，以所述二酐、二胺、极性溶剂及成孔剂的总质量为100％计，
    所述二酐与所述二胺两者的质量之和为10％～30％；优选的，所述二胺与所述二酐的摩尔比为1:(1.005～1.01)；
    所述极性溶剂的质量为70％～90％；
    所述成孔剂的质量为1％～7％。
  12. 如权利要求11所述的制备方法，其中，所述二胺包含3,3’-二甲基-4,4’-二胺基二苯甲烷和N,N'-二(4-氨基苯氧基苯基)二苯酮四酰亚胺中的至少一种；和/或
    所述二酐包含3,3’,4,4’-二苯酮四甲酸二酐、4,4'-三苯二醚二酐和均苯四甲酸酐中的至少一种；和/或
    所述成孔剂包含聚乙烯吡咯烷酮或聚乙二醇；优选的，所述聚乙二醇的分子量为200～400；和/或
    所述极性溶剂包含N-甲基吡咯烷酮、N,N-二甲基甲酰胺及四氢呋喃中的至少一种。
  13. 如权利要求10所述的制备方法，其中，在所述步骤(a 2)中，所述聚酰胺酸铸膜液涂布于基板上的厚度为5μm～200μm，优选为40μm～200μm。
  14. 如权利要求10所述的制备方法，其中，在所述步骤(a 2)中，所述凝固浴包含甲醇、乙醇、正丁醇及水中的至少一种；和/或
    所述凝固浴的温度为25℃～45℃，优选为25～30℃；和/或
    所述浸没的时间为30min～180min，优选为30min～120min。
  15. 一种复合聚酰亚胺隔膜，采用如权利要求1～14任一项所述的制备方法制得。
  16. 如权利要求15所述的复合聚酰亚胺隔膜，其中，所述隔膜包括底层基膜，和
    设置于所述底层基膜膜面上的至少一层表层膜。
  17. 一种二次电池，包括通过权利要求1～14任一项所述的制备方法制得的复合聚酰亚胺隔膜或权利要求15～16任一项所述的复合聚酰亚胺隔膜。
  18. 一种电池模块，包括权利要求17所述的二次电池。
  19. 一种电池包，包括权利要求18所述的电池模块。
  20. 一种用电装置，包括选自权利要求17所述的二次电池、权利要求18所述的电池模块或权利要求19所述的电池包中的至少一种。
PCT/CN2022/123066 2021-11-01 2022-09-30 复合聚酰亚胺隔膜及其制备方法、二次电池 WO2023071706A1 (zh)

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