WO2023205968A1 - 隔膜及包含其的装置 - Google Patents

隔膜及包含其的装置 Download PDF

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Publication number
WO2023205968A1
WO2023205968A1 PCT/CN2022/088842 CN2022088842W WO2023205968A1 WO 2023205968 A1 WO2023205968 A1 WO 2023205968A1 CN 2022088842 W CN2022088842 W CN 2022088842W WO 2023205968 A1 WO2023205968 A1 WO 2023205968A1
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WIPO (PCT)
Prior art keywords
binder
separator
porous coating
metal element
lithium
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Ceased
Application number
PCT/CN2022/088842
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English (en)
French (fr)
Inventor
熊长川
魏增斌
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Ningde Amperex Technology Ltd
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Ningde Amperex Technology Ltd
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Application filed by Ningde Amperex Technology Ltd filed Critical Ningde Amperex Technology Ltd
Priority to EP22938827.7A priority Critical patent/EP4517992A4/en
Priority to CN202510139833.4A priority patent/CN119674449A/zh
Priority to CN202280004833.8A priority patent/CN116097514B/zh
Priority to KR1020247037685A priority patent/KR20240168462A/ko
Priority to JP2024563024A priority patent/JP2025513584A/ja
Priority to PCT/CN2022/088842 priority patent/WO2023205968A1/zh
Publication of WO2023205968A1 publication Critical patent/WO2023205968A1/zh
Priority to US18/922,731 priority patent/US20250046950A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/052Li-accumulators
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/054Accumulators with insertion or intercalation of metals other than lithium, e.g. with magnesium or aluminium
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409Separators, membranes or diaphragms characterised by the material
    • H01M50/411Organic material
    • H01M50/414Synthetic resins, e.g. thermoplastics or thermosetting resins
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409Separators, membranes or diaphragms characterised by the material
    • H01M50/431Inorganic material
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409Separators, membranes or diaphragms characterised by the material
    • H01M50/446Composite material consisting of a mixture of organic and inorganic materials
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409Separators, membranes or diaphragms characterised by the material
    • H01M50/449Separators, membranes or diaphragms characterised by the material having a layered structure
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409Separators, membranes or diaphragms characterised by the material
    • H01M50/449Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/451Separators, membranes or diaphragms characterised by the material having a layered structure comprising layers of only organic material and layers containing inorganic material
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409Separators, membranes or diaphragms characterised by the material
    • H01M50/449Separators, membranes or diaphragms characterised by the material having a layered structure
    • H01M50/457Separators, membranes or diaphragms characterised by the material having a layered structure comprising three or more layers
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H01M50/491Porosity
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/489Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H01M50/494Tensile strength
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409Separators, membranes or diaphragms characterised by the material
    • H01M50/411Organic material
    • H01M50/414Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/42Acrylic resins
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50Manufacturing or production processes characterised by the final manufactured product

Definitions

  • the present application relates to the field of energy storage technology, and more specifically, to a diaphragm and a device containing the same.
  • Rechargeable electrochemical devices such as lithium-ion batteries, sodium-ion batteries
  • Rechargeable electrochemical devices are considered to be the most attractive storage devices due to their high energy density and relatively simple reaction mechanism, high operating voltage, long life, and green and environmental protection.
  • electrochemical devices have been widely used in wearable devices, smartphones, drones, laptops and other fields.
  • this application improves the safety performance of the electrochemical device by improving the separator of the electrochemical device.
  • the present application provides a separator with high safety performance, which has excellent high temperature resistance, heat shrinkage resistance, thermal puncture performance, hot box performance and cycle stability.
  • the application provides a separator, which includes: a porous substrate and a porous coating, the porous coating is disposed on at least one surface of the porous substrate, the porous coating includes an inorganic Particles and a binder, the binder includes a first binder, the first binder includes a metal element, wherein the modulus of the separator at temperature T is P, 100°C ⁇ T ⁇ 180 °C, 10 8 Pa ⁇ P ⁇ 10 9 Pa.
  • the tensile strength of the adhesive is ⁇ MPa, 0.5 ⁇ 30.
  • the melting temperature of the binder is T f ° C, 150 ⁇ T f ⁇ 250.
  • the metal element includes at least one of metal elements with a chemical valence of +1, +2 or +3.
  • the adhesive further includes a second adhesive.
  • the adhesive satisfies one of the following conditions: (a) based on the total weight of the porous coating, the first adhesive and the second adhesive The weight contents of the agents are w 1 % and w 2 % respectively, where 0.2 ⁇ w 1 ⁇ 4, 2 ⁇ w 2 ⁇ 8, and 0.025 ⁇ w 1 /w 2 ⁇ 2; (b) the first binder The pH value is pH 1 , and the pH value of the second binder is pH 2 , 7 ⁇ pH 1 ⁇ 11, 3 ⁇ pH 2 ⁇ 7, 1 ⁇ pH 1 /pH 2 ⁇ 3.6.
  • the second binder satisfies one of the following conditions: (c) Based on the total weight of the porous coating, the weight content w 2 % of the second binder satisfies 2 ⁇ w 2 ⁇ 8; (d) The pH value pH 2 of the second binder satisfies 3 ⁇ pH 2 ⁇ 7.
  • the first binder satisfies one of the following conditions: (e) the first binder only contains the metal element with a valence of +1 and a valence of +2 The metal element, wherein the molar content ratio of the metal element with a valence of +1 and the metal element with a valence of +2 is a, 1 ⁇ a ⁇ 10; or (f) the first binder It only contains the metal element with a combined valence of +1 and the metal element with a combined valence of +3, wherein the molar content ratio of the metal element with a combined valence of +1 to the metal element with a combined valence of +3 is b,1 ⁇ b ⁇ 50.
  • the metal element includes at least two of Li, Na, Ca, Mg or Al.
  • At least one of the first binder and the second binder includes a carboxyl group and/or a sulfonic acid group.
  • the binder satisfies at least one of the following conditions: (g) the first binder includes at least one of the following: sodium polymethylcellulose, Lithium polymethylcellulose, lithium polycarboxymethylcellulose, lithium polyhydroxypropylmethylcellulose, calcium polyacrylate, lithium polyacrylate or calcium polymethacrylate; or (h) the second binder Includes at least one of the following: polybutyl acrylate, polyethyl acrylate, polybutyl methacrylate, polymethyl methacrylate, or styrene-butadiene rubber.
  • the specific surface area of the inorganic particles is S BET m 2 /g, and 2 ⁇ SBET ⁇ 10 .
  • the median diameter Dv50 of the inorganic particles satisfies 0.3 ⁇ m ⁇ Dv50 ⁇ 2 ⁇ m.
  • the inorganic particles include at least one of the following: aluminum oxide, boehmite, zirconium oxide, boron nitride, silicon nitride or aluminum nitride.
  • the wetting agent includes at least one of the following: polyoxyethylene alkyl phenol ether, polyoxyethylene fatty alcohol ether, polyoxyethylene polyoxypropylene block copolymer or Silicone.
  • the thermal shrinkage rate of the separator in the MD direction is L1
  • the thermal shrinkage rate in the TD direction is L2, L1 ⁇ 10% , L2 ⁇ 10%, 0.75 ⁇ L1/L2 ⁇ 1.2.
  • the separator meets at least one of the following conditions: (i) the thickness of the separator is H ⁇ m, 3.5 ⁇ H ⁇ 14; (j) the thickness of the porous substrate is H 1 ⁇ m, 3 ⁇ H 1 ⁇ 10; or (k) the thickness of the porous coating is H 2 ⁇ m, 0.5 ⁇ H 2 ⁇ 4.
  • the porous coating satisfies at least one of the following conditions: (1) The bonding force of the porous coating is F N/m, 5 ⁇ F ⁇ 100; (m) The air permeability of the porous coating is K s/100ml, 5 ⁇ K ⁇ 40.
  • the present application also provides an electrochemical device, which includes the separator described in the above embodiments of the present application.
  • the present application also provides an electronic device, which includes the electrochemical device described in the above embodiments of the present application.
  • Figure 1 shows the shape of the separator according to the embodiment of the present application after being baked at 150° C. for 1 hour, wherein the initial length (MD) and width (TD) of the separator are 10 cm and 5 cm respectively.
  • Figure 2 shows the shape of a separator in the prior art after being baked at 150°C for 1 hour, wherein the initial length (MD) and width (TD) of the separator are 10cm and 5cm respectively.
  • a list of items connected by the term “one or more of,” “one or more of,” “at least one of” or other similar terms may mean with any combination of the items listed.
  • the phrase “at least one of A or B” means only A; only B; or both A and B.
  • the phrase “at least one of A, B, or C” means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B and C.
  • Item A may contain a single component or multiple components.
  • Item B may contain a single component or multiple components.
  • Item C may contain a single component or multiple components.
  • the separator is located between the positive and negative electrodes of the electrochemical device to transport metal ions (for example, lithium ions) while isolating the positive and negative electrodes to prevent short circuits.
  • metal ions for example, lithium ions
  • the temperature inside the electrode assembly of the electrochemical device may rise sharply, causing the separator to undergo a large degree of thermal shrinkage or even melt, resulting in direct contact between the positive and negative electrodes. short circuit. Once a short circuit occurs, thermal runaway will occur inside the electrochemical device, resulting in safety issues such as fire and explosion.
  • oil-based separators for example, aramid high-temperature resistant separators
  • electrochemical devices for example, aramid high-temperature resistant separators
  • oily separators have high requirements on production processes and can cause problems such as environmental pollution.
  • the production cost of oil-based separators is higher, so the production cost of electrochemical devices will be increased accordingly.
  • this application takes water-based separators as the research object, and improves the thermal stability and mechanical safety performance of the separators by improving the composition and content of the porous coating in the separators.
  • the separator proposed in this application includes a porous substrate and a porous coating.
  • the porous coating is provided on at least one surface of the porous substrate, wherein the porous coating includes inorganic particles and a binder.
  • a main feature of the separator of the present application is that the adhesive includes a first adhesive, the first adhesive includes a metal element, and the separator has a very high modulus at high temperatures.
  • the separator of the present application is The modulus at temperature T is P, 100°C ⁇ T ⁇ 180°C, 10 8 Pa ⁇ P ⁇ 10 9 Pa.
  • the maximum modulus of the separator in the prior art for example, the separator of Comparative Example 1-1 in the temperature range of 100°C to 180°C can only reach 9211891Pa. This shows that the separator described in the present application has good thermal stability and mechanical stability at high temperatures.
  • Figures 1 and 2 respectively show the form of the separator in one embodiment of the present application and the separator in the prior art after baking at 150°C for 1 hour.
  • the separator described in this application became transparent, with a smooth surface without any inorganic particles falling off; at the micro level, through a scanning electron microscope Observing the cross-section of the separator, it can be seen that the porous coating and the substrate are integrated, the substrate melts at 150°C, and the pores between the inorganic particles in the porous coating are also filled with the melted substrate polymer.
  • the separator in the prior art undergoes severe thermal shrinkage after being baked at 150°C for 1 hour, and a large number of inorganic particles fall off from the base material.
  • the modulus of the separator described in the present application is related to the modulus of the binder, wherein the modulus of the binder can be changed by adjusting the components, content, pH value and other factors of the binder used, and thus the modulus of the binder can be changed.
  • the modulus P of the diaphragm at high temperature can be adjusted.
  • the tensile strength of the adhesive is ⁇ MPa, where 0.5 ⁇ 30.
  • the binder can not only firmly connect the dispersed inorganic particles into a network skeleton structure, but also bond the inorganic particles and the base material together to become one, ultimately improving the The overall tensile strength of the separator enables the separator to better resist stress shock and further inhibit damage caused by impact, thereby further improving the thermal safety performance and mechanical safety performance of the electrochemical device.
  • can be, but is not limited to, 0.5, 5, 10, 15, 20, 25 or 30, or within the range of any two of the above values.
  • the melting temperature of the binder is T f °C, where 150 ⁇ T f ⁇ 250.
  • the bonding structure formed by the binder can be at appropriate strength at high temperatures to better resist stress impacts and reduce damage caused by impacts, thereby further improving the performance of the electrochemical device. Thermal safety performance and mechanical safety performance.
  • T f may be, but is not limited to, 150, 175, 200, 225 or 250, or within the range of any two of the above values.
  • the metal element in the first binder includes at least one metal element with a chemical valence of +1, +2, or +3.
  • the first binder further includes at least one of a carboxyl group or a sulfonic acid group.
  • the metal ions in the first binder can complex with the carboxyl groups or sulfonic acid groups to form metal bonds, further improving the strength of the binder (for example, tensile strength), allowing the separator to better cope with stress shocks and inhibit Damage/shrinkage caused by impact, thereby further improving the thermal safety and mechanical safety of electrochemical devices.
  • the metal element with a valence of +1 includes at least one of Li, Na, or K.
  • the metal element with a valence of +2 includes at least one of Ca, Mg or Ba.
  • the metal element with a valence of +3 includes Al.
  • the first binder includes at least one of Li, Na, Ca, Mg, or Al.
  • the adhesive includes both a first adhesive and a second adhesive.
  • the first adhesive and the second adhesive are different types of adhesives.
  • the first adhesive is a solution adhesive.
  • Solution-type adhesive means that the adhesive polymer is dissolved in a solvent to form a solution.
  • the solvent is water.
  • the second adhesive is an emulsion adhesive.
  • Emulsion adhesive refers to an adhesive polymer dispersed in a dispersion medium to form an emulsion.
  • the dispersion medium is water.
  • the functional group of the second binder includes at least one of a carboxyl group or a sulfonic acid group.
  • the binder includes both a first binder and a second binder
  • the metal ions in the first binder can complex with the carboxyl groups or sulfonic acid groups in the second binder to form metal bonds and mutual interactions.
  • the strength of the binder is further improved, and the ability of the separator to resist external impact is enhanced, thereby further improving the thermal safety performance and mechanical safety performance of the electrochemical device.
  • the strength of the adhesive can be further improved by optimizing the content and ratio of the first adhesive and the second adhesive.
  • the weight content of the first binder is w 1 % based on the total weight of the porous coating, where 0.2 ⁇ w 1 ⁇ 4.
  • w 1 can be, but is not limited to, 0.2, 0.5, 1, 1.5, 2, 2.5, 3, 3.5 or 4, or within the range of any two of the above values.
  • the weight content of the second binder is w 2 % based on the total weight of the porous coating, where 2 ⁇ w 2 ⁇ 8.
  • w 2 can be, but is not limited to, 2, 3, 4, 5, 6, 7 or 8, or within the range consisting of any two of the above values.
  • the content ratio of the first binder to the second binder (ie, w 1 /w 2 ) is in the range of 0.025 ⁇ w 1 /w 2 ⁇ 2.
  • w 1 /w 2 can be, but is not limited to, 0.025, 0.05, 0.1, 0.5, 1, 1.5 or 2, or within the range consisting of any two of the above values.
  • the pH value of the first binder can be adjusted by adjusting the content and proportion of carboxyl groups or sulfonic acid groups and metal elements in the first binder.
  • the first binder pH value is pH 1 , 7 ⁇ pH 1 ⁇ 11.
  • the first binder contains an excess of metal ions that are not complexed with the carboxyl groups or sulfonic acid groups, and these remaining metal ions can further interact with the second binder.
  • the carboxyl or sulfonic acid groups in the binder are complexed, thereby increasing the bonding strength of the binder to further improve the thermal stability and mechanical properties of the separator.
  • pH 1 may be, but is not limited to, 7, 8, 9, 10, or 11, or within a range consisting of any two of the above values.
  • the pH value of the second binder can be adjusted by adjusting the content and proportion of carboxyl groups and/or sulfonic acid groups in the second binder.
  • the pH value of the second binder is pH 2 , 3 ⁇ pH 2 ⁇ 7.
  • pH 2 can be, but is not limited to, 3, 4, 5, 6, or 7, or within a range consisting of any two of the above values.
  • the thermal stability and mechanical properties of the separator can be further improved by adjusting the pH values of the first binder and the second binder to satisfy 1 ⁇ pH 1 /pH 2 ⁇ 3.6.
  • pH 1 / pH 2 can be, but is not limited to, 1, 1.5, 2, 2.5, 3 or 3.6, or within a range consisting of any two of the above values.
  • the second binder satisfies one of the following conditions: based on the total weight of the porous coating, the weight content w 2 % of the second binder satisfies 2 ⁇ w 2 ⁇ 8; Or the pH value pH 2 of the second binder satisfies 3 ⁇ pH 2 ⁇ 7.
  • the metal elements in the first binder include at least two metal elements with a chemical valence of +1, +2, or +3. Compared with only one metal element, using at least two different metal elements in the first binder can further enhance the strength of the binder, thereby further improving the separator's ability to cope with stress shock and its stability at high temperatures. sex. This may be because compared with a single metal element, different metal elements are more likely to form interpenetrating metal bonds with carboxyl groups and/or sulfonic acid groups in the binder to build an interpenetrating cross-linked network structure, thereby improving the mechanical properties of the material.
  • the metal elements in the first binder include at least two metal elements with different valences among metal elements with a valence of +1, +2, or +3. Compared with different metal elements with the same valence state, when the first binder contains metal elements with different valence states, it is easier to form interpenetrating metal bonds with the carboxyl groups and/or sulfonic acid groups in the binder to build interpenetrating metal elements. Through the cross-linked network structure, thereby improving the mechanical properties of the material.
  • the first binder only includes metal elements with a valence of +1 and +2, wherein the molar content ratio of the metal element with a valence of +1 to the metal element with a valence of +2 is a, 1 ⁇ a ⁇ 10.
  • a can be, but is not limited to, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, or within the range consisting of any two of the above values.
  • the first binder only includes metal elements with a valence of +1 and +3, wherein the molar content ratio of the metal element with a valence of +1 to the metal element with a valence of +3 is b, 1 ⁇ b ⁇ 50.
  • b can be, but is not limited to, 1, 10, 20, 30, 40 or 50, or within the range of any two of the above values.
  • the first binder only includes metal elements with a valence of +2 and +3, wherein the molar content ratio of the metal element with a valence of +2 to the metal element with a valence of +3 is c, 1 ⁇ c ⁇ 10.
  • c can be, but is not limited to, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, or within the range of any two of the above values.
  • the metal element in the first binder includes at least two of Li, Na, Ca, Mg or Al.
  • the first adhesive meets at least one of the following conditions:
  • the first binder includes both Li and Na, where the molar content ratio of Li and Na is d, 1 ⁇ d ⁇ 8;
  • the first binder includes both Li and Mg, where the molar content ratio of Li and Mg is e, 2 ⁇ e ⁇ 4;
  • the first binder includes both Na and Mg, where the molar content ratio of Na and Mg is f, 2 ⁇ f ⁇ 4;
  • the first binder includes both Li and Ca, where the molar content ratio of Li and Ca is g, 2 ⁇ 9 ⁇ 4;
  • the first binder includes both Na and Ca, where the molar content ratio of Na and Ca is m, 2 ⁇ m ⁇ 4;
  • the first binder includes both Li and Al, where the molar content ratio of Li and Al is n, 1 ⁇ n ⁇ 20;
  • the first binder includes both Na and Al, where the molar content ratio of Na and Al is p, 1 ⁇ p ⁇ 20.
  • the first binder includes, but is not limited to, at least one of the following: sodium polymethylcellulose, lithium polymethylcellulose, lithium polycarboxymethylcellulose, polyhydroxymethylcellulose Lithium propylmethylcellulose, calcium polyacrylate, lithium polyacrylate, or calcium polymethacrylate.
  • the second binder includes, but is not limited to, at least one of the following: polybutyl acrylate, polyethyl acrylate, polybutyl methacrylate, polymethyl methacrylate, or Styrene-butadiene rubber.
  • the specific surface area of the inorganic particles located in the porous coating is S BET m 2 /g, and 2 ⁇ SBET ⁇ 10 .
  • S BET may be, but is not limited to, 2, 3, 4, 5, 6, 7, 8, 9 or 10, or within the range of any two of the above values.
  • 2 ⁇ SBET ⁇ 5 may be, but is not limited to, 2, 3, 4, 5, 6, 7, 8, 9 or 10, or within the range of any two of the above values.
  • the median particle diameter Dv50 of the inorganic particles satisfies 0.3 ⁇ m ⁇ Dv50 ⁇ 2 ⁇ m, where Dv50 is the particle diameter value corresponding to when the percentage in the volume distribution reaches 50%.
  • Dv50 is the particle diameter value corresponding to when the percentage in the volume distribution reaches 50%.
  • inorganic particles that can be used in the separator of the present application include, but are not limited to, at least one of the following: aluminum oxide, boehmite, zirconia, boron nitride, silicon nitride, nitrogen Aluminum, silicon dioxide, magnesium oxide, titanium oxide, silicon carbide, aluminum hydroxide or magnesium hydroxide.
  • the porous coating further includes a wetting agent, where the function of the wetting agent is to improve the wettability of the porous coating slurry to the substrate and avoid coating leakage during the coating process.
  • a wetting agent where the function of the wetting agent is to improve the wettability of the porous coating slurry to the substrate and avoid coating leakage during the coating process.
  • the weight content of the inorganic particles is m 1 %
  • the weight content of the binder is m 2 %
  • the wetting agent includes, but is not limited to, at least one of the following: polyoxyethylene alkyl phenol ether, polyoxyethylene fatty alcohol ether, polyoxyethylene polyoxypropylene block copolymer, or Silicone.
  • the separator of the present application is placed at 150° C. for 1 hour.
  • the thermal shrinkage rate of the separator in the length (MD) direction is L1.
  • the thermal shrinkage rate of the separator is L1.
  • the thermal shrinkage rate in the width (TD) direction is L2, where L1 ⁇ 10%, L2 ⁇ 10%, and 0.75 ⁇ L1/L2 ⁇ 1.2.
  • L1 and L2 may be, but are not limited to, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, or 9%, respectively, or any two of the above. within the range of values.
  • L1/L2 may be, but is not limited to, 0.8, 0.9, 1.0, 1.1 or 1.2, or within the range consisting of any two of the above values.
  • the thickness of the separator described herein is H ⁇ m, where 3.5 ⁇ H ⁇ 14.
  • H may be, but is not limited to, 3.5, 5, 7, 9, 10, 12, or 14, or within a range consisting of any two of the above values.
  • the porous substrate described in the present application may include, but is not limited to, at least one of the following: polyethylene (PE), ultra-high molecular weight polyethylene (UHMWPE), high-density polyethylene (HDPE) ), polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), cellulose, polyimide, polystyrene (PS), poly4-methyl- 1-Pentene (TPX), polymethylmethacrylate (PMMA), polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), polytetrafluoroethylene (PTFE) and polysulfone .
  • PE polyethylene
  • UHMWPE ultra-high molecular weight polyethylene
  • HDPE high-density polyethylene
  • PP polypropylene
  • PET polyethylene terephthalate
  • PPS polyphenylene sulfide
  • the thickness of the porous substrate described herein is H 1 ⁇ m, where 3 ⁇ H 1 ⁇ 10.
  • H 1 may be, but is not limited to, 3, 4, 5, 6, 7, 8, 9 or 10, or within a range consisting of any two of the above values.
  • the thickness of the porous coating described herein is H 2 ⁇ m, where 0.5 ⁇ H 2 ⁇ 4.
  • H2 may be, but is not limited to, 0.5, 1, 1.5, 2, 2.5, 3, 3.5 or 4, or within a range consisting of any two of the above values.
  • the "thickness of the porous coating" mentioned above refers to the sum of the thicknesses of the porous coatings coated on the two surfaces. .
  • the adhesion force of the porous coating is F N/m, 5 ⁇ F ⁇ 100.
  • F may be, but is not limited to, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90 or 100, or within a range consisting of any two of the above values. In some embodiments, 20 ⁇ F ⁇ 85.
  • the air permeability of the porous coating is K s/100 ml, 5 ⁇ K ⁇ 40.
  • K may be, but is not limited to, 5, 10, 15, 20, 25, 30, 35 or 40, or within a range consisting of any two of the above values.
  • the present application further provides an electrochemical device, which includes the separator of the above embodiment of the present application.
  • the electrochemical device further includes a negative electrode, a positive electrode, and an electrolyte, wherein the separator is located between the positive electrode and the negative electrode.
  • this application will describe the composition of the positive electrode, negative electrode and electrolyte in detail.
  • the positive electrode includes a positive electrode material that includes a positive electrode material capable of absorbing and releasing lithium (Li) (hereinafter, sometimes referred to as a “positive electrode material capable of absorbing/releasing lithium Li”).
  • Examples of cathode materials capable of absorbing/releasing lithium (Li) may include lithium cobalt oxide, lithium nickel cobalt manganate, lithium nickel cobalt aluminate, lithium manganate, lithium iron manganese phosphate, lithium vanadium phosphate, lithium vanadium oxyphosphate, phosphoric acid Lithium iron, lithium titanate and lithium-rich manganese-based materials.
  • M1 means selected from nickel (Ni), manganese (Mn), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), Copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), tungsten (W), yttrium (Y), lanthanum (La), zirconium (Zr) and At least one kind of silicon (Si), x1, a1, b1 and c1 values are respectively in the following ranges: 0.8 ⁇ x1 ⁇ 1.2, 0.8 ⁇ a1 ⁇ 1, 0 ⁇ b1 ⁇ 0.2, -0.1 ⁇ c1 ⁇ 0.2;
  • the chemical formula of lithium nickel cobalt manganate or lithium nickel cobalt aluminate can be as chemical formula 2:
  • M2 means selected from cobalt (Co), manganese (Mn), magnesium (M g ), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe) , at least one of copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr), tungsten (W), zirconium (Zr) and silicon (Si) , the values of y1, d1, e1 and f1 are respectively within the following ranges: 0.8 ⁇ y1 ⁇ 1.2, 0.3 ⁇ d1 ⁇ 0.98, 0.02 ⁇ e1 ⁇ 0.7, -0.1 ⁇ f1 ⁇ 0.2;
  • the chemical formula of lithium manganate can be as follows: Chemical Formula 3:
  • M3 means selected from cobalt (Co), nickel (Ni), magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), At least one of copper (Cu), zinc (Zn), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr) and tungsten (W), z1, g1 and h1 values are in the following ranges respectively Within: 0.8 ⁇ z1 ⁇ 1.2, 0 ⁇ g1 ⁇ 1.0 and -0.2 ⁇ h1 ⁇ 0.2.
  • the negative electrode includes a negative electrode material, and the negative electrode material includes a negative electrode material capable of absorbing and releasing lithium (Li) (hereinafter, sometimes referred to as “negative electrode material capable of absorbing/releasing lithium Li”).
  • negative electrode material capable of absorbing/releasing lithium (Li) may include carbon materials, metal compounds, oxides, sulfides, lithium nitrides such as LiN 3 , lithium metal, metals alloyed with lithium, and polymer materials.
  • Examples of the carbon material may include low graphitizable carbon, readily graphitizable carbon, artificial graphite, natural graphite, mesophase carbon microspheres, soft carbon, hard carbon, pyrolytic carbon, coke, glassy carbon, sintered organic polymer compound body, carbon fiber and activated carbon.
  • coke may include pitch coke, needle coke and petroleum coke.
  • the organic polymer compound sintered body refers to a material obtained by calcining a polymer material such as phenol plastic or furan resin at an appropriate temperature to carbonize it, and some of these materials are classified into low-graphitizable carbon or easy-graphitizable carbon.
  • Examples of polymeric materials may include polyacetylene and polypyrrole.
  • negative electrode materials capable of absorbing/releasing lithium Li
  • a material whose charge and discharge voltage is close to that of lithium metal is selected. This is because the lower the charge and discharge voltage of the negative electrode material, the easier it is for an electrochemical device (such as a lithium-ion battery) to have a higher energy density.
  • carbon materials can be selected as the negative electrode material because their crystal structure only changes slightly during charging and discharging. Therefore, good cycle characteristics and large charging and discharging capacities can be obtained.
  • Graphite is especially chosen because it gives a large electrochemical equivalent and a high energy density.
  • the negative electrode material capable of absorbing/releasing lithium (Li) may include elemental lithium metal, metallic elements and semi-metal elements capable of forming alloys with lithium (Li), including alloys and compounds of such elements, and the like. In particular, they are used together with carbon materials because in this case good cycle characteristics as well as high energy density can be obtained.
  • alloys containing two or more metallic elements alloys as used herein also include alloys containing one or more metallic elements and one or more semi-metallic elements. The alloy can be in the following states: solid solutions, eutectic crystals (eutectic mixtures), intermetallic compounds, and mixtures thereof.
  • Examples of metallic elements and semi-metal elements may include tin (Sn), lead (Pb), aluminum (Al), indium (In), silicon (Si), zinc (Zn), antimony (Sb), bismuth (Bi), Cadmium (Cd), magnesium (Mg), boron (B), gallium (Ga), germanium (Ge), arsenic (As), silver (Ag), zirconium (Zr), yttrium (Y) and hafnium (Hf).
  • Examples of the above alloys and compounds may include materials having the chemical formula: Ma s Mb t Li u and materials having the chemical formula: Map Mc q Md r .
  • Ma represents at least one element among metallic elements and semi-metal elements capable of forming an alloy with lithium
  • Mb represents at least one element among metallic elements and semi-metal elements other than lithium and Ma
  • Mc represents at least one element among non-metallic elements
  • Md represents at least one element among metallic elements and semi-metallic elements except Ma
  • s, t, u, p, q and r satisfy s>0, t ⁇ 0, u ⁇ 0, p>0, q>0 and r ⁇ 0.
  • inorganic compounds excluding lithium (Li), such as MnO 2 , V 2 O 5 , V 6 O 13 , NiS, and MoS, may be used in the negative electrode.
  • the electrolyte may be one or more of a gel electrolyte, a solid electrolyte, and an electrolyte solution, and the electrolyte solution includes a lithium salt and a non-aqueous solvent.
  • the lithium salt is selected from LiPF 6 , LiBF 4 , LiAsF 6 , LiClO 4 , LiB(C 6 H 5 ) 4 , LiCH 3 SO 3 , LiCF 3 SO 3 , LiN(SO 2 CF 3 ) 2 , LiC(SO 2 CF 3 ) 3 , one or more of LiSiF 6 , LiBOB and lithium difluoroborate.
  • LiPF 6 was chosen for the lithium salt because it gives high ionic conductivity and improves cycle characteristics.
  • the non-aqueous solvent may be a carbonate compound, a carboxylate compound, an ether compound, other organic solvents, or a combination thereof.
  • the carbonate compound may be a chain carbonate compound, a cyclic carbonate compound, a fluorocarbonate compound, or a combination thereof.
  • chain carbonate compounds are diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), methyl carbonate Ethyl ester (MEC) and its combinations.
  • chain carbonate compounds are diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), methyl carbonate Ethyl ester (MEC) and its combinations.
  • Examples of cyclic carbonate compounds are ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), vinylethylene carbonate (VEC) and combinations thereof.
  • fluorocarbonate compounds are fluoroethylene carbonate (FEC), 1,2-difluoroethylene carbonate, 1,1-difluoroethylene carbonate, 1,1,2-trifluoroethylene carbonate.
  • Ethyl ester 1,1,2,2-tetrafluoroethylene carbonate, 1-fluoro-2-methylethylene carbonate, 1-fluoro-1-methylethylene carbonate, 1,2-dicarbonate Fluoro-1-methylethylene carbonate, 1,1,2-trifluoro-2-methylethylene carbonate, trifluoromethylethylene carbonate and combinations thereof.
  • carboxylate compounds are methyl acetate, ethyl acetate, n-propyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, propyl propionate, ⁇ -butyrolactone, decanolactone, Valerolactone, mevalonolactone, caprolactone, methyl formate and combinations thereof.
  • ether compounds are dibutyl ether, tetraglyme, diglyme, 1,2-dimethoxyethane, 1,2-diethoxyethane, ethoxymethoxy ethane, 2-methyltetrahydrofuran, tetrahydrofuran and combinations thereof.
  • organic solvents examples include dimethyl sulfoxide, 1,2-dioxolane, sulfolane, methylsulfolane, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolidone, methane Amides, dimethylformamide, acetonitrile, trimethyl phosphate, triethyl phosphate, trioctyl phosphate, and phosphate esters and combinations thereof.
  • the electrochemical device of the present application includes any device that undergoes an electrochemical reaction, and specific examples thereof include all kinds of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors.
  • the electrochemical device is a lithium secondary battery, including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery or a lithium ion polymer secondary battery.
  • the present application further provides an electronic device, which includes the electrochemical device according to the present application.
  • the use of the electrochemical device of the present application is not particularly limited, and it can be used in any electronic device known in the art.
  • the electrochemical device of the present application can be used in, but is not limited to, notebook computers, pen-input computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, headsets, etc.
  • Stereo headphones video recorders, LCD TVs, portable cleaners, portable CD players, mini discs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power supplies, motors, cars, motorcycles, boosters Bicycles, bicycles, lighting equipment, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries and lithium-ion capacitors, etc.
  • Preparation process of acrylic adhesive 1. Add an appropriate amount of acrylic monomer into the reaction kettle, add an appropriate amount of catalyst, and stir evenly at a slow speed; 2. Add an appropriate amount of sulfonic acid group-containing monomer or carboxyl monomer (for example: methane propanesulfonic acid or methacrylic acid) into the reaction kettle; 3. Pour in inert gas into the reaction kettle to form a reaction protective atmosphere; 4. The reaction kettle is heated to the reaction temperature, and the monomers are polymerized to obtain a sticky product containing both functional groups. Binder; 5. After the reaction is completed, the required binder can be obtained by adding metal alkali and adjusting the pH of the binder discharge.
  • sulfonic acid group-containing monomer or carboxyl monomer for example: methane propanesulfonic acid or methacrylic acid
  • binders containing different functional groups By changing the type of reactive monomers, binders containing different functional groups can be obtained. Selecting different types of metal alkali (such as sodium hydroxide, magnesium hydroxide) or adding metal alkali at different contents can realize the design and control of the type and content ratio of the metal alkali in the binder.
  • metal alkali such as sodium hydroxide, magnesium hydroxide
  • cellulose binder The preparation process of cellulose binder: 1. Place an appropriate amount of raw cellulose in a reaction kettle, then add a metal alkali (sodium hydroxide) to alkalize the cellulose to obtain alkalized cellulose; 2. Alkalization Add an appropriate amount of chloroacetic acid to cellulose to carry out etherification reaction, and finally obtain cellulose sodium binder.
  • a metal alkali sodium hydroxide
  • the design and control of the type and content ratio of the metal alkali in the binder can be achieved.
  • Lithium salt LiPF6 and non-aqueous organic solvent ethylene carbonate (EC): diethyl carbonate (DEC): propylene carbonate (PC): propyl propionate (PP): vinylene carbonate (VC)
  • EC ethylene carbonate
  • DEC diethyl carbonate
  • PC propylene carbonate
  • PP propyl propionate
  • VC vinylene carbonate
  • a solution prepared at a mass ratio of 20:30:20:28:2 (mass ratio) of 8:92 is used as the electrolyte for lithium-ion batteries.
  • the electrode assembly is placed in the outer packaging, electrolyte is injected and packaged, and the final lithium-ion battery product is made after chemical formation.
  • Test method steps First, cut the diaphragm to a certain size (8mm ⁇ 50mm) and place it in the DMA test fixture; then, start the DMA modulus test program, and obtain the diaphragm temperature-modulus curve after the test is completed. Based on the temperature-modulus curve, the modulus of the separator at a certain temperature can be read.
  • the universal testing machine applies stress to stretch the sample at a constant rate (20mm/min), causing the sample to elongate in the axial direction and produce tensile deformation until the sample ruptures or breaks.
  • Pmax unit: N
  • W and T are the initial width and initial thickness of the adhesive film sample, respectively, where the units of the initial width and initial thickness are mm.
  • Test method steps Take a certain amount (5-10mg) of the adhesive film and place it in the crucible of the instrument.
  • the instrument is heated at 10°C/min to 30-50°C above the melting extrapolation end temperature to eliminate the thermal history of the material; then the instrument Cool down to 30-50°C below the expected crystallization temperature at 10°C/min; then heat to 30-50°C above the melting extrapolation end temperature at 10°C/min, and measure the melting temperature; compare the sample mass before and after the measurement, and if there is weight loss, Repeat the above process, commonly used test standards: ISO 11357-3-2011, ASTM E794-06 (2012), ASTM D3418-12 E1 , GB 19466.3-2004.
  • the DSC absorption curve is obtained. Since the melting temperature range of the polymer binder is wide, the entire melting process may be accompanied by a complex melting/recrystallization/crystallization adjustment process. Therefore, the polymer binder’s The melting temperature is usually taken as the absorption peak temperature.
  • test software start the test software, take a certain amount of inorganic particles and place them in the sample testing chamber, and use the BET specific surface area measurement method to test the specific surface area of the inorganic particles. After the test is completed, the test software automatically reads the specific surface area value of the inorganic particles.
  • test software place the inorganic particles that meet the test quality requirements into the test chamber of the Malvern 3000 laser particle size analyzer, then start ultrasonic for 5 minutes to ensure that the particles are not agglomerated, and then enter the particle size test step, and the software outputs the particle size distribution curve.
  • MD1 10cm
  • TD1 5cm
  • CCD camera to measure the length and width of the separator sample after baking at 150°C for 1 hour, and record them as MD2 and TD2, respectively.
  • calculate the thermal shrinkage rate L1 of the separator in the MD direction and the thermal shrinkage rate L2 of the separator in the TD direction through the following formulas:
  • L1 (MD1-MD2)/MD1;
  • the thickness of the substrate and the separator were measured using a desktop separator thickness gauge and recorded as H 1 ⁇ m and H ⁇ m respectively. Calculate the thickness H 2 ⁇ m of the porous coating using the following formula:
  • H 2 HH 1 .
  • Test method steps First, take a substrate of a certain size (5x5cm) and place it on the air permeability test platform to measure the air permeability G1s/100ml of the substrate; then, take a substrate of a certain size (5x5cm) and coat it with a porous coating membrane of a certain thickness and place it on the test platform.
  • the air permeability test platform measured the air permeability of the base material G2s/100ml.
  • the base material of the porous coating separator is the same as the test base material for air permeability.
  • the porous coating air permeability test generally tests 6 parallel samples and takes the average value;
  • the hot box pass rate refers to the ratio of the number of lithium-ion batteries that pass the test to the total number of lithium-ion batteries.
  • Table 1 shows the effect of the pH value of the binder on the properties of the separator and the electrochemical properties of the lithium-ion battery.
  • the thickness of the porous coating is 3.0 ⁇ m; the porous substrate component is PE and the thickness is 6.0 ⁇ m.
  • the substrate and the porous coating are integrated during the heating process, so the thickness of the separator after heating is smaller than the initial separator thickness.
  • the separator described in the comparative example shrinks severely at high temperatures, and many ridges/protruding structures appear on the surface, causing the thickness of the separator after heating to be greater than the initial separator thickness.
  • Table 2 is an improvement based on Example 1-1, and the only difference lies in the contents of the first binder and the second binder. It can be seen from the data in Table 2 that by further adjusting the contents of the first binder and the second binder respectively, 0.2 ⁇ w 1 ⁇ 4, 2 ⁇ w 2 ⁇ 8, and 0.025 ⁇ w 1 /w 2 ⁇ 2. It can further improve the tensile strength of the binder, the thermal stability of the separator, and the safety performance and cycle stability of the electrochemical device.
  • Table 3 is an improvement based on Example 1-1. The only difference lies in the type and content of the metal elements added in the first binder. As shown in Table 3, compared with adding only one metal element, after adding two metal elements, the tensile strength of the binder, the thermal stability of the separator, and the safety performance and cycle stability of the electrochemical device were all improved. made further improvements. In addition, it can also be seen that adding metal elements with different valences to the first binder further improves the performance of the binder, separator, and electrochemical device.
  • Table 4 is an improvement based on Examples 3-9. The only difference lies in the components, median particle size and content of the inorganic particles. It can be seen from Examples 3-9 to 4-5 that high temperatures can be obtained by selecting aluminum oxide, boehmite, zirconia, boron nitride, silicon nitride or aluminum nitride as inorganic particles in the porous coating. High performance separators and electrochemical devices.
  • Table 5 is an improvement based on Examples 3-9, the difference is only in the components and content of the wetting agent. It can be seen from Examples 3-9 to 5-3 that polyoxyethylene alkyl phenol ether, polyoxyethylene fatty alcohol ether, polyoxyethylene polyoxypropylene block copolymer or siloxane are selected as the polyoxyethylene alkyl phenol ether in the porous coating. Wetting agents can produce separators and electrochemical devices with excellent high-temperature performance.
  • Table 6 is an improvement based on Examples 3-9, and the only difference lies in the thickness of the porous coating and the porous substrate. It can be seen from Examples 3-9 to 6-6 that when the thickness H 2 of the porous coating is in the range of 0.5 ⁇ H 2 ⁇ 4, separators and electrochemical devices with better high-temperature performance can be obtained. It can be seen from Examples 6-7 to 6-13 that when the thickness H 1 of the porous substrate is in the range of 3 ⁇ H 1 ⁇ 10, separators and electrochemical devices with better high-temperature performance can be obtained.
  • references throughout the specification to “embodiment”, “partial embodiment”, “one embodiment”, “another example”, “example”, “specific example” or “partial example” mean that At least one embodiment or example in this application includes a specific feature, structure, material or characteristic described in the embodiment or example. Accordingly, phrases such as “in some embodiments,” “in an embodiment,” “in one embodiment,” “in another example,” “in one example,” etc. may appear in various places throughout this specification. "in”, “in a particular example” or “for example” do not necessarily refer to the same embodiment or example in this application. Furthermore, the specific features, structures, materials, or characteristics herein may be combined in any suitable manner in one or more embodiments or examples.

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Abstract

提供一种隔膜及包含其的装置。具体而言,提供的隔膜包括:多孔基材和多孔涂层,多孔涂层设置在多孔基材的至少一个表面上,多孔涂层包括无机颗粒和粘结剂。隔膜具有优异的热安全稳定性和机械稳定性,这主要表现在:隔膜在温度T下的模量为P,100℃≤T≤180℃,10 8Pa≤P≤10 9Pa。

Description

隔膜及包含其的装置 技术领域
本申请涉及储能技术领域,更具体地,涉及一种隔膜及包含其的装置。
背景技术
由于具有高能量密度和相对简单的反应机理、工作电压高、寿命长、绿色环保等优点,可再充电的电化学装置(如锂离子电池、钠离子电池)被认为是最具吸引力的储能系统之一。如今,电化学装置已经广泛地应用于可穿戴设备、智能手机、无人机、笔记本电脑等各个领域中。
随着电化学装置在各个领域的广泛应用,人们对电化学装置的要求越来越高,例如有些时候,当电化学装置在一些极端环境(如撞击、穿钉以及热箱)下工作或者被滥用时,人们仍然需要电化学装置能够安全工作而不会发生起火、爆炸等危险。然而,目前现有技术中的电化学装置难以满足上述需求。有鉴于此,亟需改进电化学装置的安全性能,尤其是改善电化学装置在极端环境下的安全性能。
发明内容
至少为了解决上述问题,本申请通过对电化学装置的隔膜进行改进以改善电化学装置的安全性能。具体的,本申请提供了一种具有高安全性能的隔膜,所述隔膜具有优异的耐高温性能、耐热收缩性能、热穿刺性能、热箱性能以及循环稳定性。
根据本申请的一个方面,本申请提供一种隔膜,其包括:多孔基材和多孔涂层,所述多孔涂层设置在所述多孔基材的至少一个表面上,所述多孔涂层包括无机颗粒和粘结剂,所述粘结剂包括第一粘结剂,所述第一粘结剂包括金属元素,其中,所述隔膜在温度T下的模量为P,100℃≤T≤180℃,10 8Pa≤P≤10 9Pa。
根据本申请的实施例,其中,所述粘结剂的拉伸强度为αMPa,0.5≤α≤30。
根据本申请的实施例,其中,所述粘结剂的熔融温度为T f℃,150≤T f≤250。
根据本申请的实施例,其中,所述金属元素包括化合价为+1、+2或+3的金属元素中的至少一种。
根据本申请的实施例,其中,所述粘结剂还包括第二粘结剂。
根据本申请的实施例,其中,所述粘结剂满足以下条件中的其中一者:(a)基于所述多孔涂层的总重量,所述第一粘结剂和所述第二粘结剂的重量含量分别为w 1%和w 2%,其中0.2≤w 1≤4,2≤w 2≤8,且0.025≤w 1/w 2≤2;(b)所述第一粘结剂pH值为pH 1,所述第二粘结剂pH值为pH 2,7≤pH 1≤11,3≤pH 2≤7,1≤pH 1/pH 2≤3.6。
根据本申请的实施例,其中,第二粘结剂满足以下条件的其中一者:(c)基于所述多孔涂层的总重量,所述第二粘结剂的重量含量w 2%满足2≤w 2≤8;(d)所述第二粘结剂的pH值pH 2满足3≤pH 2≤7。
根据本申请的实施例,其中,所述第一粘结剂满足以下条件的其中一者:(e)所述第一粘结剂仅包含化合价为+1的所述金属元素和化合价为+2的所述金属元素,其中化合价为+1的所述金属元素与化合价为+2的所述金属元素的摩尔含量比为a,1≤a≤10;或(f)所述第一粘结剂仅包含化合价为+1的所述金属元素和化合价为+3的所述金属元素,其中化合价为+1的所述金属元素与化合价为+3的所述金属元素的摩尔含量比为b,1≤b≤50。
根据本申请的实施例,其中,所述金属元素包括Li、Na、Ca、Mg或Al中的至少两种。
根据本申请的实施例,其中,所述第一粘结剂和所述第二粘结剂中的至少一者包括羧基和/或磺酸基。
根据本申请的实施例,其中,所述粘结剂满足以下条件中的至少一者:(g)所述第一粘结剂包括以下各者中的至少一种:聚甲基纤维素钠、聚甲基纤维素锂、聚羧甲基纤维素锂、聚羟丙基甲基纤维素锂、聚丙烯酸钙、聚丙烯酸锂或聚甲基丙烯酸钙;或(h)所述第二粘结剂包括以下各者中的至少一种:聚丙烯酸丁酯、聚丙烯酸乙酯、聚甲基丙烯酸丁酯、聚甲基丙烯酸甲酯或丁苯橡胶。
根据本申请的实施例,其中,所述无机颗粒的比表面积为S BET m 2/g,2≤S BET≤10。
根据本申请的实施例,其中,所述无机颗粒的中值粒径Dv50满足0.3μm≤Dv50≤2μm。
根据本申请的实施例,其中,所述无机颗粒包括以下各者中的至少一者:三氧化二铝、勃姆石、氧化锆、氮化硼、氮化硅或氮化铝。
根据本申请的实施例,其中,所述多孔涂层还包括润湿剂,其中以所述多孔涂层的总重量计,所述无机颗粒的重量含量为m 1%,所述粘结剂的重量含量为m 2%,所述润湿剂的重量含量为m 3%,其中90≤m 1≤96,3≤m 2≤9,0.5≤m 3≤1.5,且m 1+m 2+m 3=100。
根据本申请的实施例,其中,所述润湿剂包括以下各者中的至少一种:聚氧乙烯烷基酚醚、聚氧乙烯脂肪醇醚、聚氧乙烯聚氧丙烯嵌段共聚物或硅氧烷。
根据本申请的实施例,其中,将所述隔膜在150℃下放置1小时,所述隔膜在MD方向上的热收缩率为L1,在TD方向上的热收缩率为L2,L1<10%,L2<10%,0.75≤L1/L2≤1.2。
根据本申请的实施例,其中,所述隔膜满足以下条件中的至少一者:(i)所述隔膜的厚度为Hμm,3.5≤H≤14;(j)所述多孔基材的厚度为H 1μm,3≤H 1≤10;或者(k)所述多孔涂层的厚度为H 2μm,0.5≤H 2≤4。
根据本申请的实施例,其中,所述多孔涂层满足以下条件中的至少一者:(1)所述多孔涂层的粘结力为F N/m,5≤F≤100;(m)所述多孔涂层的透气度为K s/100ml,5≤K≤40。
根据本申请的另一个方面,本申请还提供了一种电化学装置,其包括本申请上述实施例所述的隔膜。
根据本申请的另一个方面,本申请还提供了一种电子装置,其包括本申请上述实施例所述的电化学装置。
附图说明
在下文中将简要地说明为了描述本申请实施例或现有技术所必要的附图以便于描述本申请的实施例。显而易见地,下文描述中的附图仅只是本申请中的部分实施例。对本领域技术人员而言,在不需要创造性劳动的前提下,依然可以根据这些附图中所例示的结构来获得其他实施例的附图。
图1示出了本申请实施例所述隔膜经150℃烘烤1小时后的形态,其中所述隔膜的初始长度(MD)和宽度(TD)分别为10cm和5cm。
图2示出了现有技术中的隔膜经150℃烘烤1小时后的形态,其中所述隔膜 的初始长度(MD)和宽度(TD)分别为10cm和5cm。
具体实施方式
本申请的实施例将会被详细的描示在下文中。本申请的实施例不应该被解释为对本申请的限制。
如本申请所用,术语“包括”、“含有”和“包含”以其开放、非限制性含义使用。
另外,有时在本文中以范围格式呈现量、比率和其它数值。应理解,此类范围格式是用于便利及简洁起见,且应灵活地理解,不仅包含明确地指定为范围限制的数值,而且包含涵盖于范围内的所有个别数值或子范围,如同明确地指定每一数值及子范围一般。
在具体实施方式及权利要求书中,由术语“中的一者或多者”、“中的一个或多个”、“中的至少一种”或其他相似术语所连接的项目的列表可意味着所列项目的任何组合。例如,如果列出项目A及B,那么短语“A或B中的至少一种”意味着仅A;仅B;或A及B。在另一实例中,如果列出项目A、B及C,那么短语“A、B或C中的至少一种”意味着仅A;或仅B;仅C;A及B(排除C);A及C(排除B);B及C(排除A);或A、B及C的全部。项目A可包含单个元件或多个元件。项目B可包含单个元件或多个元件。项目C可包含单个元件或多个元件。
隔膜
隔膜作为电化学装置的重要组成部分,位于电化学装置的正极和负极之间以在传输金属离子(例如,锂离子)的同时隔离正极和负极,实现防止短路的功能。然而,当被非正常使用或者被滥用时,电化学装置的电极组件内部的温度可能会急剧升高,导致隔膜产生较大程度的热收缩甚至熔融,从而造成正负极之间直接接触而发生短路。一旦发生短路,电化学装置内部会发生热失控,从而发生起火、爆炸等安全问题。
现有技术通常会在电化学装置中采用油性隔膜(例如,芳纶耐高温隔膜)来提高隔膜对高温的耐受性。然而,油性隔膜对生产工艺的要求很高,且会产生环境污染等问题。另外,相比于水性隔膜,油性隔膜的生产成本较高,因此会相应的增加电化学装置的生产成本。
至少基于对现有技术的上述洞察,本申请以水性隔膜作为研究对象,通过改 善隔膜中多孔涂层的成分和其含量来提高隔膜的热稳定性和机械安全性能。具体的,本申请提出的隔膜包括多孔基材和多孔涂层,多孔涂层设置在多孔基材的至少一个表面上,其中多孔涂层包括无机颗粒和粘结剂。本申请隔膜的一个主要特征在于:所述粘结剂包括第一粘结剂,所述第一粘结剂包括金属元素,隔膜在高温下具有很高的模量,例如本申请所述隔膜在温度T下的模量为P,100℃≤T≤180℃,10 8Pa≤P≤10 9Pa。与之相比,现有技术中的隔膜(例如,对比例1-1的隔膜)在100℃至180℃的温度范围内的最大模量仅能够达到9211891Pa。由此可以说明,本申请所述隔膜在高温下具有很好的热稳定性和机械稳定性。
另外,图1和图2分别示出了本申请其中一个实施例中的隔膜和现有技术中的隔膜在150℃下烘烤1小时后的形态。如图1所示,在经过150℃下烘烤1小时后,在宏观层面上,本申请所述的隔膜变得透明、表面平整且没有任何无机颗粒脱落;在微观层面上,通过扫描电子显微镜观察隔膜断面能够看出,多孔涂层与基材融为一体,150℃基材熔融,多孔涂层中无机颗粒之间的孔隙也被熔融后的基材聚合物填充。与之相比,如图2所示,现有技术中的隔膜在经过150℃下烘烤1小时后发生严重的热收缩,且有大量的无机颗粒从基材上脱落。
在一些实施例中,本申请所述隔膜的模量与粘结剂的模量相关,其中通过调整所用粘结剂的组分、含量、pH值等因素能够改变粘结剂的模量,进而能够调整隔膜在高温下的模量P。
在一些实施例中,粘结剂的拉伸强度为αMPa,其中0.5≤α≤30。当粘结剂的拉伸强度处于上述范围内时,粘结剂不仅能够将分散的无机颗粒牢固地连接成网络骨架结构,还能够将无机颗粒与基材粘接在一起从而成为一体,最终提高隔膜整体的拉伸强度,使得隔膜能够更好地抵抗应力冲击,进一步抑制冲击导致的破损,从而进一步改善电化学装置的热安全性能和机械安全性能。在一些实施例中,α可以,但不限于为0.5、5、10、15、20、25或30,或者处于上述任意两个数值所组成的范围内。
在一些实施例中,粘结剂的熔融温度为T f℃,其中150≤T f≤250。当粘结剂的熔融温度处于上述范围内时,粘结剂形成的粘接结构在高温下能够处于适当的强度以更好地抵抗应力冲击,减少冲击造成的破损,从而进一步改善电化学装置的热安全性能和机械安全性能。在一些实施例中,T f可以,但不限于为150、175、200、225或250,或者处于上述任意两个数值所组成的范围内。
在一些实施例中,第一粘结剂中的金属元素包括化合价为+1、+2或+3的金属元素中的至少一种。在一些实施例中,第一粘结剂还包括羧基或磺酸基中的至少一种。第一粘结剂中的金属离子能够与其中的羧基或磺酸基络合形成金属键,进一步提高粘结剂的强度(例如,拉伸强度),使得隔膜能够更好地应对应力冲击,抑制冲击导致的破损/收缩,从而进一步改善电化学装置的热安全性能和机械安全性能。
在一些实施例中,化合价为+1的金属元素包括Li、Na或K中的至少一种。在一些实施例中,化合价为+2的金属元素包括Ca、Mg或Ba中的至少一种。在一些实施例中,化合价为+3的金属元素包括Al。在一些实施例中,第一粘结剂包括Li、Na、Ca、Mg或Al中的至少一者。
在一些实施例中,粘结剂同时包括第一粘结剂和第二粘结剂。在一些实施例中,第一粘结剂和第二粘结剂为不同类型的粘结剂。例如,第一粘结剂为溶液型粘接剂。溶液型粘接剂是指粘接剂高分子溶解在溶剂中形成溶液。在一些实施例中,溶剂是水。第二粘结剂为乳液性粘结剂。乳液性粘结剂是指粘接剂高分子分散在分散介质中形成乳液。在一些实施例中,分散介质是水。
在一些实施例中,第二粘结剂的功能基团包括羧基或磺酸基中的至少一种。当粘结剂同时包括第一粘结剂和第二粘结剂时,第一粘结剂中的金属离子能够与第二粘结剂中的羧基或磺酸基络合,形成金属键和互穿网络结构,从而进一步提高粘结剂的强度,加强隔膜抵制外力冲击的能力,从而进一步改善电化学装置的热安全性能和机械安全性能。
此外,当粘结剂同时包括第一粘结剂和第二粘结剂时,通过优化第一粘结剂和第二粘结剂的含量及其比值能够进一步提高粘结剂的强度。在一些实施例中,基于多孔涂层的总重量,第一粘结剂的重量含量为w 1%,其中0.2≤w 1≤4。在一些实施例中,w 1可以,但不限于为0.2、0.5、1、1.5、2、2.5、3、3.5或4,或者处于上述任意两个数值所组成的范围内。
在一些实施例中,基于多孔涂层的总重量,第二粘结剂的重量含量为w 2%,其中2≤w 2≤8。在一些实施例中,w 2可以,但不限于为2、3、4、5、6、7或8,或者处于上述任意两个数值所组成的范围内。
在一些实施例中,第一粘结剂与第二粘结剂的含量比(即,w 1/w 2)处于0.025≤w 1/w 2≤2的范围内。在一些实施例中,w 1/w 2可以,但不限于为0.025、0.05、 0.1、0.5、1、1.5或2,或者处于上述任意两个数值所组成的范围内。
在一些实施例中,通过调整第一粘结剂中羧基或磺酸基以及金属元素的含量和比例能够调整第一粘结剂的pH值。在一些实施例中,第一粘结剂pH值为pH 1,7≤pH 1≤11。当第一粘结剂的pH值处于上述范围内时,第一粘结剂中含有过量的未与其中的羧基或磺酸基络合的金属离子,而这些剩余的金属离子能够进一步与第二粘结剂中的羧基或磺酸基络合,从而提高粘结剂的粘结强度以进一步改善隔膜的热稳定性和机械性能。在一些实施例中,pH 1可以,但不限于为7、8、9、10或11,或者处于上述任意两个数值所组成的范围内。
在一些实施例中,通过调整第二粘结剂中羧基和/或磺酸基的含量和比例能够调整第二粘结剂的pH值。在一些实施例中,第二粘结剂pH值为pH 2,3≤pH 2≤7。当第二粘结剂的pH值处于上述范围内时,能够提供大量的羧基和/或磺酸基以与第一粘结剂中的金属离子络合,改善粘结剂的力学性能以进一步改善隔膜的热稳定性和机械性能。在一些实施例中,pH 2可以,但不限于为3、4、5、6或7,或者处于上述任意两个数值所组成的范围内。
在一些实施例中,通过调整第一粘结剂和第二粘结剂的pH值满足1≤pH 1/pH 2≤3.6能够进一步改善隔膜的热稳定性和机械性能。在一些实施例中,pH 1/pH 2可以,但不限于为1、1.5、2、2.5、3或3.6,或者处于上述任意两个数值所组成的范围内。
在一些实施例中,第二粘结剂满足以下条件的其中一者:基于所述多孔涂层的总重量,所述第二粘结剂的重量含量w 2%满足2≤w 2≤8;或者所述第二粘结剂的pH值pH 2满足3≤pH 2≤7。
在一些实施例中,第一粘结剂中的金属元素包括化合价为+1、+2或+3的金属元素中的至少两种。相较于仅含有一种金属元素,在第一粘结剂中使用至少两种不同的金属元素能够进一步增强粘结剂的强度,从而进一步改善隔膜应对应力冲击的能力以及其在高温下的稳定性。这可能是由于相较于单一金属元素,不同的金属元素更易与粘结剂中的羧基和/或磺酸基形成互穿金属键以构建互穿交联网络结构,从而改善材料力学性能。
在一些实施例中,第一粘结剂中的金属元素包括化合价为+1、+2或+3的金属元素中的至少两种不同化合价的金属元素。相较于具有相同价态的不同金属元素,当第一粘结剂含有不同价态的金属元素时,更容易与粘结剂中的羧基和/或 磺酸基形成互穿金属键以构建互穿交联网络结构,从而改善材料力学性能。
在一些实施例中,第一粘结剂仅包括化合价为+1和+2的金属元素,其中化合价为+1的金属元素与化合价为+2的金属元素的摩尔含量比为a,1≤a≤10。在一些实施例中,a可以,但不限于为1、2、3、4、5、6、7、8、9或10,或者处于上述任意两个数值所组成的范围内。
在一些实施例中,第一粘结剂仅包括化合价为+1和+3的金属元素,其中化合价为+1的金属元素与化合价为+3的金属元素的摩尔含量比为b,1≤b≤50。在一些实施例中,b可以,但不限于为1、10、20、30、40或50,或者处于上述任意两个数值所组成的范围内。
在一些实施例中,第一粘结剂仅包括化合价为+2和+3的金属元素,其中化合价为+2的金属元素与化合价为+3的金属元素的摩尔含量比为c,1≤c≤10。在一些实施例中,c可以,但不限于为1、2、3、4、5、6、7、8、9或10,或者处于上述任意两个数值所组成的范围内。
在一些实施例中,第一粘结剂中的金属元素包括Li、Na、Ca、Mg或Al中的至少两种。
在一些实施例中,第一粘结剂满足以下条件中的至少一者:
(1)第一粘结剂同时包括Li和Na,其中Li和Na的摩尔含量比为d,1≤d≤8;
(2)第一粘结剂同时包括Li和Mg,其中Li和Mg的摩尔含量比为e,2≤e≤4;
(3)第一粘结剂同时包括Na和Mg,其中Na和Mg的摩尔含量比为f,2≤f≤4;
(4)第一粘结剂同时包括Li和Ca,其中Li和Ca的摩尔含量比为g,2≤9≤4;
(5)第一粘结剂同时包括Na和Ca,其中Na和Ca的摩尔含量比为m,2≤m≤4;
(6)第一粘结剂同时包括Li和Al,其中Li和Al的摩尔含量比为n,1≤n≤20;
(7)第一粘结剂同时包括Na和Al,其中Na和Al的摩尔含量比为p,1≤p≤20。
在一些实施例中,第一粘结剂包括,但不限于,以下各者中的至少一种:聚甲基纤维素钠、聚甲基纤维素锂、聚羧甲基纤维素锂、聚羟丙基甲基纤维素锂、聚丙烯酸钙、聚丙烯酸锂、或聚甲基丙烯酸钙。
在一些实施例中,第二粘结剂包括,但不限于,以下各者中的至少一种:聚丙烯酸丁酯、聚丙烯酸乙酯、聚甲基丙烯酸丁酯、聚甲基丙烯酸甲酯或丁苯橡胶。
在一些实施例中,位于多孔涂层中的无机颗粒的比表面积为S BET m 2/g, 2≤S BET≤10。在一些实施例中,S BET可以,但不限于为2、3、4、5、6、7、8、9或10,或者处于上述任意两个数值所组成的范围内。在一些实施例中,2≤S BET≤5。
在一些实施例中,无机颗粒的中值粒径Dv50满足0.3μm≤Dv50≤2μm,其中Dv50为体积分布中百分数达到50%时所对应的粒径值。当无机颗粒的粒径处于上述范围内时,既有利于对多孔涂层的厚度进行减薄,提高电化学装置的能量密度,又能够确保粘接位点处于合适的范围内,降低粘结剂的用量,改善电化学装置的动力学性能。
在一些实施例中,可用于本申请隔膜的无机颗粒包括,但不限于,以下各者中的至少一种:三氧化二铝、勃姆石、氧化锆、氮化硼、氮化硅、氮化铝、二氧化硅、氧化镁、氧化钛、碳化硅、氢氧化铝或氢氧化镁。
在一些实施例中,多孔涂层还包括润湿剂,其中润湿剂的作用在于改善多孔涂层浆料对基材的润湿性,避免涂布加工过程中发生漏涂。此外,通过优化无机颗粒、粘结剂和润湿剂在多孔涂层中的重量占比,能够进一步增强隔膜的热安全性能和机械稳定性。在一些实施例中,以多孔涂层的总重量计,无机颗粒的重量含量为m 1%,粘结剂的重量含量为m 2%,润湿剂的重量含量为m 3%,其中90≤m 1≤96,3≤m 2≤9,0.5≤m 3≤1.5,且m 1+m 2+m 3=100。
在一些实施例中,润湿剂包括,但不限于,以下各者中的至少一种:聚氧乙烯烷基酚醚、聚氧乙烯脂肪醇醚、聚氧乙烯聚氧丙烯嵌段共聚物或硅氧烷。
在一些实施例中,将本申请隔膜在150℃下放置1小时,相较于隔膜的初始长度,隔膜在长度(MD)方向上的热收缩率为L1,相较于隔膜的初始宽度,隔膜在宽度(TD)方向上的热收缩率为L2,其中L1<10%,L2<10%,0.75≤L1/L2≤1.2。在一些实施例中,L1和L2可以,但不限于,分别为1%,2%,3%,4%,5%,6%,7%,8%,或9%,或者处于上述任意两个数值所组成的范围内。在一些实施例中,L1/L2可以为,但不限于,0.8、0.9、1.0、1.1或1.2,或者处于上述任意两个数值所组成的范围内。
在一些实施例中,本申请所述隔膜的厚度为Hμm,其中3.5≤H≤14。在一些实施例中,H可以为,但不限于,3.5、5、7、9、10、12或14,或者处于由上述任意两个数值组成的范围内。
在一些实施例中,本申请所述多孔基材可以包括,但不限于,以下各者中的至少一种:聚乙烯(PE)、超高分子量聚乙烯(UHMWPE)、高密度聚乙烯(HDPE)、 聚丙烯(PP)、聚对苯二甲酸乙二醇酯(PET)、聚苯硫醚(PPS)、纤维素、聚酰亚胺、聚苯乙烯(PS)、聚4-甲基-1-戊烯(TPX)、聚甲基丙烯酸甲酯(PMMA)、聚偏氟乙烯(PVDF)、聚偏氟乙烯-六氟丙烯(PVDF-HFP)、聚四氟乙烯(PTFE)和聚砜。
在一些实施例中,本申请所述多孔基材的厚度为H 1μm,其中3≤H 1≤10。在一些实施例中,H 1可以为,但不限于,3、4、5、6、7、8、9或10,或者处于由上述任意两个数值组成的范围内。
在一些实施例中,本申请所述多孔涂层的厚度为H 2μm,其中0.5≤H 2≤4。当多孔涂层的厚度处于上述范围内时,既能够提高电化学装置的能量密度,还能够改善电化学装置的动力学性能。在一些实施例中,H 2可以为,但不限于,0.5、1、1.5、2、2.5、3、3.5或4,或者处于由上述任意两个数值组成的范围内。其中,当多孔基材的两个表面上均涂覆有多孔涂层时,上述提到的“多孔涂层的厚度”指的是这两个表面上经涂覆的多孔涂层的厚度之和。
在一些实施例中,多孔涂层的粘结力为F N/m,5≤F≤100。当多孔涂层的粘结力处于上述范围内时,不仅能够使无机颗粒牢固地粘结至多孔基材上而不易脱落,而且还不必使用过多的粘结剂从而恶化电化学装置的动力学性能。在一些实施例中,F可以为,但不限于,5、10、20、30、40、50、60、70、80、90或100,或者处于由上述任意两个数值组成的范围内。在一些实施例中,20≤F≤85。
在一些实施例中,多孔涂层的透气度为K s/100ml,5≤K≤40。在一些实施例中,K可以为,但不限于,5、10、15、20、25、30、35或40,或者处于由上述任意两个数值组成的范围内。
本申请另提供了一种电化学装置,其包含本申请上述实施例的隔膜。在一些实施例中,电化学装置还包括负极、正极和电解液,其中隔膜位于正极和负极之间。如下,本申请将详细描述正极、负极和电解质的组成。
正极
正极包括正极材料,正极材料包括能够吸收和释放锂(Li)的正极材料(下文中,有时称为“能够吸收/释放锂Li的正极材料”)。能够吸收/释放锂(Li)的正极材料的例子可以包括钴酸锂、镍钴锰酸锂、镍钴铝酸锂、锰酸锂、磷酸锰铁锂、磷酸钒锂、磷酸钒氧锂、磷酸铁锂、钛酸锂和富锂锰基材料。
具体的,钴酸锂的化学式可以如化学式1:
Li x1Co a1Ml b1O 2-c1   化学式1
其中M1表示选自镍(Ni)、锰(Mn)、镁(Mg)、铝(Al)、硼(B)、钛(Ti)、钒(V)、铬(Cr)、铁(Fe)、铜(Cu)、锌(Zn)、钼(Mo)、锡(Sn)、钙(Ca)、锶(Sr)、钨(W)、钇(Y)、镧(La)、锆(Zr)和硅(Si)中的至少一种,x1、a1、b1和c1值分别在以下范围内:0.8≤x1≤1.2、0.8≤a1≤1、0≤b1≤0.2、-0.1≤c1≤0.2;
镍钴锰酸锂或镍钴铝酸锂的化学式可以如化学式2:
Li y1Ni d1M2 e1O 2-f1   化学式2
其中M2表示选自钴(Co)、锰(Mn)、镁(M g)、铝(Al)、硼(B)、钛(Ti)、钒(V)、铬(Cr)、铁(Fe)、铜(Cu)、锌(Zn)、钼(Mo)、锡(Sn)、钙(Ca)、锶(Sr)、钨(W)、锆(Zr)和硅(Si)中的至少一种,y1、d1、e1和f1值分别在以下范围内:0.8≤y1≤1.2、0.3≤d1≤0.98、0.02≤e1≤0.7、-0.1≤f1≤0.2;
锰酸锂的化学式可以如化学式3:
Li z1Mn 2-g1M 3g1O 4-h1   化学式3
其中M3表示选自钴(Co)、镍(Ni)、镁(Mg)、铝(Al)、硼(B)、钛(Ti)、钒(V)、铬(Cr)、铁(Fe)、铜(Cu)、锌(Zn)、钼(Mo)、锡(Sn)、钙(Ca)、锶(Sr)和钨(W)中的至少一种,z1、g1和h1值分别在以下范围内:0.8≤z1≤1.2、0≤g1<1.0和-0.2≤h1≤0.2。
负极
负极包括负极材料,负极材料包括能够吸收和释放锂(Li)的负极材料(下文中,有时称为“能够吸收/释放锂Li的负极材料”)。能够吸收/释放锂(Li)的负极材料的例子可以包括碳材料、金属化合物、氧化物、硫化物、锂的氮化物例如LiN 3、锂金属、与锂一起形成合金的金属和聚合物材料。
碳材料的例子可以包括低石墨化的碳、易石墨化的碳、人造石墨、天然石墨、中间相碳微球、软碳、硬碳、热解碳、焦炭、玻璃碳、有机聚合物化合物烧结体、碳纤维和活性碳。其中,焦炭可以包括沥青焦炭、针状焦炭和石油焦炭。有机聚合物化合物烧结体指的是通过在适当的温度下煅烧聚合物材料例如苯酚塑料或者呋喃树脂以使之碳化获得的材料,将这些材料中的一些分成低石墨化碳或者易石墨化的碳。聚合物材料的例子可以包括聚乙炔和聚吡咯。
在能够吸收/释放锂(Li)的这些负极材料中,更进一步地,选择充电和放电电压接近于锂金属的充电和放电电压的材料。这是因为负极材料的充电和放电 电压越低,电化学装置(例如锂离子电池)越容易具有更高的能量密度。其中,负极材料可以选择碳材料,因为在充电和放电时它们的晶体结构只有小的变化,因此,可以获得良好的循环特性以及大的充电和放电容量。尤其可以选择石墨,因为它可以给出大的电化学当量和高的能量密度。
此外,能够吸收/释放锂(Li)的负极材料可以包括单质锂金属、能够和锂(Li)一起形成合金的金属元素和半金属元素,包括这样的元素的合金和化合物等等。特别地,将它们和碳材料一起使用,因为在这种情况中,可以获得良好的循环特性以及高能量密度。除了包括两种或者多种金属元素的合金之外,这里使用的合金还包括包含一种或者多种金属元素和一种或者多种半金属元素的合金。该合金可以处于以下状态固溶体、共晶晶体(共晶混合物)、金属间化合物及其混合物。
金属元素和半金属元素的例子可以包括锡(Sn)、铅(Pb)、铝(Al)、铟(In)、硅(Si)、锌(Zn)、锑(Sb)、铋(Bi)、镉(Cd)、镁(Mg)、硼(B)、镓(Ga)、锗(Ge)、砷(As)、银(Ag)、锆(Zr)、钇(Y)和铪(Hf)。上述合金和化合物的例子可以包括具有化学式:Ma sMb tLi u的材料和具有化学式:Ma pMc qMd r的材料。在这些化学式中,Ma表示能够与锂一起形成合金的金属元素和半金属元素中的至少一种元素;Mb表示除锂和Ma之外的金属元素和半金属元素中的至少一种元素;Mc表示非金属元素中的至少一种元素;Md表示除Ma之外的金属元素和半金属元素中的至少一种元素;并且s、t、u、p、q和r满足s>0、t≥0、u≥0、p>0、q>0和r≥0。
此外,可以在负极中使用不包括锂(Li)的无机化合物,例如MnO 2、V 2O 5、V 6O 13、NiS和MoS。
电解质
电解质可以是凝胶电解质、固态电解质和电解液中的一种或多种,电解液包括锂盐和非水溶剂。
锂盐选自LiPF 6、LiBF 4、LiAsF 6、LiClO 4、LiB(C 6H 5) 4、LiCH 3SO 3、LiCF 3SO 3、LiN(SO 2CF 3) 2、LiC(SO 2CF 3) 3、LiSiF 6、LiBOB和二氟硼酸锂中的一种或多种。例如,锂盐选用LiPF 6,因为它可以给出高的离子导电率并改善循环特性。
非水溶剂可为碳酸酯化合物、羧酸酯化合物、醚化合物、其它有机溶剂或它们的组合。
碳酸酯化合物可为链状碳酸酯化合物、环状碳酸酯化合物、氟代碳酸酯化合物或其组合。
链状碳酸酯化合物的实例为碳酸二乙酯(DEC)、碳酸二甲酯(DMC)、碳酸二丙酯(DPC)、碳酸甲丙酯(MPC)、碳酸乙丙酯(EPC)、碳酸甲乙酯(MEC)及其组合。环状碳酸酯化合物的实例为碳酸亚乙酯(EC)、碳酸亚丙酯(PC)、碳酸亚丁酯(BC)、碳酸乙烯基亚乙酯(VEC)及其组合。氟代碳酸酯化合物的实例为碳酸氟代亚乙酯(FEC)、碳酸1,2-二氟亚乙酯、碳酸1,1-二氟亚乙酯、碳酸1,1,2-三氟亚乙酯、碳酸1,1,2,2-四氟亚乙酯、碳酸1-氟-2-甲基亚乙酯、碳酸1-氟-1-甲基亚乙酯、碳酸1,2-二氟-1-甲基亚乙酯、碳酸1,1,2-三氟-2-甲基亚乙酯、碳酸三氟甲基亚乙酯及其组合。
羧酸酯化合物的实例为乙酸甲酯、乙酸乙酯、乙酸正丙酯、乙酸叔丁酯、丙酸甲酯、丙酸乙酯、丙酸丙酯、γ-丁内酯、癸内酯、戊内酯、甲瓦龙酸内酯、己内酯、甲酸甲酯及其组合。
醚化合物的实例为二丁醚、四甘醇二甲醚、二甘醇二甲醚、1,2-二甲氧基乙烷、1,2-二乙氧基乙烷、乙氧基甲氧基乙烷、2-甲基四氢呋喃、四氢呋喃及其组合。
其它有机溶剂的实例为二甲亚砜、1,2-二氧戊环、环丁砜、甲基环丁砜、1,3-二甲基-2-咪唑烷酮、N-甲基-2-吡咯烷酮、甲酰胺、二甲基甲酰胺、乙腈、磷酸三甲酯、磷酸三乙酯、磷酸三辛酯、和磷酸酯及其组合。
本申请的电化学装置包括发生电化学反应的任何装置,它的具体实例包括所有种类的一次电池、二次电池、燃料电池、太阳能电池或电容。特别地,该电化学装置是锂二次电池,包括锂金属二次电池、锂离子二次电池、锂聚合物二次电池或锂离子聚合物二次电池。
本申请另提供了一种电子装置,其包括根据本申请的电化学装置。
本申请的电化学装置的用途没有特别限定,其可用于现有技术中已知的任何电子装置。在一些实施例中,本申请的电化学装置可用于,但不限于,笔记本电脑、笔输入型计算机、移动电脑、电子书播放器、便携式电话、便携式传真机、便携式复印机、便携式打印机、头戴式立体声耳机、录像机、液晶电视、手提式清洁器、便携CD机、迷你光盘、收发机、电子记事本、计算器、存储卡、便携式录音机、收音机、备用电源、电机、汽车、摩托车、助力自行车、自行车、照 明器具、玩具、游戏机、钟表、电动工具、闪光灯、照相机、家庭用大型蓄电池和锂离子电容器等。
下面以锂离子电池为例并且结合具体的实施例说明锂离子电池的制备,本领域的技术人员将理解,本申请中描述的制备方法仅是实例,其他任何合适的制备方法均在本申请的范围内。
实施例
以下说明根据本申请的锂离子电池的实施例和对比例进行的性能评估。
一、锂离子电池的制备
1、粘结剂的制备
丙烯酸类粘结剂的制备过程:1、将适量丙烯酸单体加入到反应釜中,并加入适量催化剂,慢速搅拌均匀;2、加入适量含磺酸基单体或者羧基单体(例如:甲基丙磺酸或者甲基丙烯酸)到反应釜;3、反应釜通入惰性气体形成反应保护气氛;4、反应釜升温加热至反应温度,单体聚合,得到同时含有两种功能基团的粘结剂;5、反应完成后,可通过加入金属碱,调整粘结剂出料pH,即可得到所需粘结剂。
其中通过改变反应单体类型,可以得到含有不同功能基团的粘结剂。选择不同类型金属碱(例如:氢氧化钠,氢氧化镁)或者不同含量添加的金属碱,可以实现粘结剂中金属碱类型与含量比例的设计调控。
纤维素类粘结剂的制备过程:1、将适量原料纤维素置于反应釜,然后加入金属碱(氢氧化钠),对纤维素碱化处理,得到碱化的纤维素;2、碱化纤维素中加入适量氯乙酸,进行醚化反应,最后得到纤维素钠粘结剂。
其中,在碱化处理过程中,通过更换金属碱类型或者金属碱比例等相关工艺参数,可以实现粘结剂中金属碱类型与含量比例的设计调控。
2、隔膜的制备方法
将水与无机颗粒充分混合后,再加入一定量的粘接剂,放入搅拌器中搅拌均匀。随后将一定量的润湿剂加入上述浆料中,继续搅拌直至混合均匀。最后,在基材PE一侧均匀涂覆至合适的厚度,待涂覆完成后放入烘箱中干燥,得到本申请的隔膜。其中无机颗粒、粘结剂和润湿剂的成分和含量以及涂覆厚度等参数详见表1。
3、锂离子电池的制备方法
将正极活性物质钴酸锂、导电碳(Super P)和粘结剂聚偏二氟乙烯(PVDF)按重量比96∶2∶2溶解于N-甲基吡咯烷酮溶剂体系中,充分搅拌混合均匀,制得正极浆料。将正极浆料涂覆于铝箔上、烘干、冷压、分条,得到正极。
将负极活性物质人造石墨、导电剂(Super P)、粘结剂丁苯橡胶和增稠剂羧甲基纤维素钠按照重量比98∶0.5∶1∶0.5溶解于去离子水溶剂体系中,充分搅拌混合均匀,制得负极浆料。将负极浆料涂覆于铜箔上、烘干、冷压、分条,得到负极。
将锂盐LiPF6与非水有机溶剂(碳酸乙烯酯(EC)∶碳酸二乙酯(DEC)∶碳酸亚丙酯(PC)∶丙酸丙酯(PP)∶碳酸亚乙烯酯(VC))=20∶30∶20∶28∶2,质量比)按质量比8∶92配制而成的溶液作为锂离子电池的电解液。
将正极、隔离膜和负极按顺序叠好,使隔离膜处于正极和负极中间,卷绕得到电极组件。将电极组件置于外包装中,注入电解液并封装,进行化成之后制成最终的锂离子电池产品。
二、测试方法
1、隔膜的模量测试
测试仪器:DMA(动态热机械分析仪)
测试方法步骤:首先,将隔膜裁切一定尺寸(8mm×50mm),置于DMA测试夹具;然后,启动DMA模量测试程序,测试完成得到隔膜温度-模量曲线。基于温度-模量曲线,可以读取在某一温度下的隔膜模量。
2、粘接剂的拉伸强度测试
将粘接剂胶膜样品置于万能试验机的拉伸测试夹具上,并竖直固定夹具。万能试验机以恒定速率(20mm/min)施加应力拉伸样品,使样品沿轴向伸长产生拉伸变形,直到样品破裂或者断裂为止。读取万能试验机施加的最大负荷应力值Pmax(单位为N),并通过以下公式计算粘接剂的拉伸强度α:
α=Pmax/(W×T),
其中W和T分别为粘接剂胶膜样品的初始宽度和初始厚度,其中初始宽度和初始厚度的单位为mm。
3、粘接剂的熔融温度测试
测试仪器:DCS(差示扫描量热法);
测试方法步骤:取一定量(5-10mg)粘结剂胶膜置于仪器坩埚中,仪器以 10℃/min加热至熔融外推终止温度以上30-50℃,以消除材料热历史;然后仪器以10℃/min降温到预期的结晶温度以下30-50℃;再10℃/min加热至熔融外推终止温度以上30-50℃,测定熔融温度;对比测定前后样品质量,如发现有失重则重复以上过程,常用测试标准:ISO 11357-3-2011、ASTM E794-06(2012)、ASTM D3418-12 E1、GB 19466.3-2004。
熔融温度计算:测试完成后得到DSC吸收曲线,由于高分子粘结剂熔融温度范围较宽,整个熔融过程中可能伴有复杂的熔融/重结晶/晶型调整过程,因此高分子粘结剂的熔融温度通常取吸收峰值温度。
4、粘接剂中金属元素及其含量比的测定
将电池放入手套箱中拆解,取出隔膜并去除涂布在多孔涂层上的PVDF/PMMA胶层之后,留下多孔涂层,再通过“水洗”方式将多孔涂层重新分散在水中,经离心分离无机颗粒后得到水洗清液,水洗清液中包括粘结剂。通过电感耦合等离子体(ICP)测试测定水洗清液,得到粘接剂中金属元素及其含量比。
5、无机颗粒的比表面积测试
启动测试软件,取一定量的无机颗粒置于样品测试仓,采用BET比表面积测定方法测试无机颗粒的比表面积。测试完成后,测试软件自动读取无机颗粒的比表面积数值。
6、无机颗粒的粒径测试
启动测试软件,将满足测试质量要求的无机颗粒置于马尔文3000型激光粒度仪的测试仓中,然后启动超声5分钟以确保颗粒无团聚,之后进入测试粒径步骤,由软件输出粒径分布曲线。
7、隔膜在MD和TD方向上的热收缩测试
首先,将隔膜裁切为长度为MD1和宽度为TD1的尺寸(MD1=10cm,TD1=5cm),得到测试隔膜样品。其次,将裁切好的隔膜样品放于两张A4纸之间,置于150℃烘箱中烘烤1小时。然后,用CCD相机测量于150℃烘烤1小时后的隔膜样品的长度和宽度,分别记为MD2和TD2。最后,通过以下公式计算隔膜在MD方向上的热收缩率L1和隔膜在TD方向上的热收缩率L2:
L1=(MD1-MD2)/MD1;
L2=(TD 1-TD2)/TD 1。
8、隔膜、基材和多孔涂层的厚度测试
利用台式隔膜测厚仪分别测定基材和隔膜的厚度,并分别记作H 1μm和Hμm。利用如下公式计算多孔涂层的厚度H 2μm:
H 2=H-H 1
9、多孔涂层的粘结力测试
首先,将涂布好的隔膜样品平铺在玻璃板上,保持多孔涂层朝上,四边用胶带固定,确保隔膜平整固定在玻璃板上;其次,用剥离力测试专用胶带平直地贴附在多孔涂层的表面;然后,用1KG压辊来回碾压剥离力测试专用胶带粘贴区域;之后,在剥离力测试专用胶带粘贴区域裁切出15mm×54.2mm隔膜测试样品;最后,将隔膜测试样品一侧固定在高铁拉力机一端,胶带侧固定在高铁拉力机移动支架一端,移动支架以一定的速度拉伸胶带,使得胶带从隔膜表面180°剥离,测试软件读取数值即为多孔涂层的粘结力。
10、多孔涂层的透气度测试
测试仪器:Gurley透气度仪
测试方法步骤:首先,取一定大小(5x5cm)的基材置于透气度仪测试平台测定出基材透气度G1s/100ml;然后,取一定大小(5x5cm)涂覆一定厚度多孔涂层隔膜置于透气度仪测试平台测定出基材透气度G2s/100ml。
多孔涂层的透气度G3计算:G3=G2-G1,即为多孔涂层的透气度。
多孔涂层隔膜的基材与测试基材透气度基材相同,多孔涂层透气度测试一般测试6个平行样,取平均值;
11、在150℃中烘烤1小时后的隔膜厚度测试
将隔膜放置于150℃的烘箱中烘烤1小时,用离子束切割仪将隔膜切断,形成断面;随后,使用扫描电子显微镜测量隔膜断面的厚度,即为在150℃中烘烤1小时后的隔膜厚度。
12、热箱测试
取100个锂离子电池样品,在常温下以0.5C倍率恒定电流充电至4.5V,进一步在4.5V恒定电压下充电至电流低于0.05C,使其处于4.5V满充状态。将锂离子电池样品放入烘箱中,在137℃中放置1h,锂离子电池若没有发生冒烟、起火、爆炸,则记为通过,反之则记为不通过。热箱通过率是指通过测试的锂离子电池数量与锂离子电池总数的比值。
13、穿钉测试
首先,在穿钉测试前后检查电池外观并拍照;其次,将感温线黏贴在电池表面的中心处;然后,在20±5℃测试环境中,将测试电池放置于测试台面,使用2.5mm直径的钢钉以150mm/s的速度从样品中心位置测试,样品完全刺穿;若电池不起火也不爆炸,则说明电池通过测试。
三、测试结果
表1展示了粘结剂的pH值对隔膜性质和锂离子电池的电化学性质的影响,其中多孔涂层的厚度为3.0μm;多孔基材成分为PE,厚度为6.0μm。
从表1中可以看出,相较于对比例,在实施例中通过调整第一粘结剂和第二粘结剂的pH值分别满足7≤pH 1≤11和3≤pH 2≤7,且其比值pH 1/pH 2满足1≤pH 1/pH 2≤3.6,(1)能够得到具有较大拉伸强度和较高熔融温度的粘结剂;(2)在经历150℃烘烤1小时后,实施例中的隔膜的厚度更小且MD和TD热收缩率更低;(3)实施例中的电化学装置全部通过热箱测试和穿钉测试。在经历150℃烘烤1小时后,对于实施例所述的隔膜而言,在加热的过程中,基材与多孔涂层融为一体,因此加热后的隔膜厚度要小于初始隔膜厚度。与之相比,对比例所述的隔膜在高温下出现严重收缩,且表面出现很多隆起/突出结构,导致加热后的隔膜厚度反而会大于初始隔膜厚度。
表2是在实施例1-1的基础上进行的改进,其差别仅在于第一粘结剂和第二粘结剂的含量不同。从表2的数据可以看出,通过进一步调整第一粘结剂和第二粘结剂的含量分别满足0.2≤w 1≤4,2≤w 2≤8,且0.025≤w 1/w 2≤2,能够进一步改善粘结剂的拉伸强度、隔膜的热稳定性以及电化学装置的安全性能和循环稳定性。
表3是在实施例1-1的基础上进行的改进,其差别仅在于第一粘结剂中添加的金属元素的种类和含量不同。如表3所示,相较于仅添加一种金属元素,添加了两种金属元素后,粘结剂的拉伸强度、隔膜的热稳定性以及电化学装置的安全性能和循环稳定性均得到了进一步的改进。另外,还可以看出,在第一粘结剂中添加具有不同化合价的金属元素会进一步改善粘结剂、隔膜和电化学装置的性能。
从表3中可以看出,当化合价为+1的金属元素与化合价为+2的金属元素的含量比a处于1≤a≤10的范围内时,能够进一步改善粘结剂、隔膜和电化学装置的性能;当化合价为+1的金属元素与化合价为+3的金属元素的含量比b处于1<b<50的范围内时,能够进一步改善粘结剂、隔膜和电化学装置的性能。
表4是在实施例3-9的基础上进行的改进,其差别仅在于无机颗粒的组分、中值粒径和含量不同。从实施例3-9至4-5可以看出,选用三氧化二铝、勃姆石、氧化锆、氮化硼、氮化硅或氮化铝作为多孔涂层中的无机颗粒均可以获得高温性能优异的隔膜和电化学装置。
从实施例4-6至4-12可以看出,当无机颗粒的中值粒径Dv50满足0.3μm≤Dv50≤2μm,能够得到高温性能更优异的隔膜和电化学装置。
从实施例4-13至4-18可以看出,以所述多孔涂层的总重量计,当无机颗粒的重量含量m 1%满足90≤m 1≤96,能够得到高温性能更优异的隔膜和电化学装置。
表5是在实施例3-9的基础上进行的改进,其差别仅在于润湿剂的组分和含量不同。从实施例3-9至5-3可以看出,选用聚氧乙烯烷基酚醚、聚氧乙烯脂肪醇醚、聚氧乙烯聚氧丙烯嵌段共聚物或硅氧烷作为多孔涂层中的润湿剂均可以获得高温性能优异的隔膜和电化学装置。
从实施例5-3至5-7可以看出,以所述多孔涂层的总重量计,当润湿剂的重量含量m 3%满足0.5≤m 3≤1.5,能够得到高温性能更优异的隔膜和电化学装置。
表6是在实施例3-9的基础上进行的改进,其差别仅在于多孔涂层和多孔基材的厚度不同。从实施例3-9至6-6可以看出,当多孔涂层的厚度H 2处于0.5≤H 2≤4的范围内时,能够得到高温性能更优异的隔膜和电化学装置。从实施例6-7至6-13可以看出,当多孔基材的厚度H 1处于3≤H 1≤10的范围内时,能够得到高温性能更优异的隔膜和电化学装置。
整个说明书中对“实施例”、“部分实施例”、“一个实施例”、“另一举例”、“举例”、“具体举例”或“部分举例”的引用,其所代表的意思是在本申请中的至少一个实施例或举例包含了该实施例或举例中所描述的特定特征、结构、材料或特性。因此,在整个说明书中的各处所出现的描述,例如:“在一些实施例中”、“在实施例中”、“在一个实施例中”、“在另一个举例中”、“在一个举例中”、“在特定举例中”或“举例”,其不必然是引用本申请中的相同的实施例或示例。此外,本文中的特定特征、结构、材料或特性可以以任何合适的方式在一个或多个实施例或举例中结合。
尽管已经演示和描述了说明性实施例,本领域技术人员应该理解上述实施例不能被解释为对本申请的限制,并且可以在不脱离本申请的精神、原理及范围的 情况下对实施例进行改变,替代和修改。
Figure PCTCN2022088842-appb-000001
Figure PCTCN2022088842-appb-000002
Figure PCTCN2022088842-appb-000003
Figure PCTCN2022088842-appb-000004
Figure PCTCN2022088842-appb-000005
Figure PCTCN2022088842-appb-000006
Figure PCTCN2022088842-appb-000007
Figure PCTCN2022088842-appb-000008
Figure PCTCN2022088842-appb-000009
Figure PCTCN2022088842-appb-000010

Claims (21)

  1. 一种隔膜,其包括:
    多孔基材和多孔涂层,所述多孔涂层设置在所述多孔基材的至少一个表面上,所述多孔涂层包括无机颗粒和粘结剂,所述粘结剂包括第一粘结剂,所述第一粘结剂包括金属元素,其中,所述隔膜在温度T下的模量为P,100℃≤T≤180℃,10 8Pa≤P≤10 9Pa。
  2. 根据权利要求1所述的隔膜,其中,所述粘结剂的拉伸强度为αMPa,0.5≤α≤30。
  3. 根据权利要求1所述的隔膜,其中,所述粘结剂的熔融温度为T f℃,150≤T f≤250。
  4. 根据权利要求1所述的隔膜,其中,所述金属元素包括化合价为+1、+2或+3的金属元素中的至少一种。
  5. 根据权利要求1所述的隔膜,其中,所述粘结剂还包括第二粘结剂。
  6. 根据权利要求5所述的隔膜,其中,所述粘结剂满足以下条件中的其中一者:
    (a)基于所述多孔涂层的总重量,所述第一粘结剂和所述第二粘结剂的重量含量分别为w 1%和w 2%,其中0.2≤w 1≤4,2≤w 2≤8,且0.025≤w 1/w 2≤2;
    (b)所述第一粘结剂pH值为pH 1,所述第二粘结剂pH值为pH 2,7≤pH 1≤11,3≤pH 2≤7,1≤pH 1/pH 2≤3.6。
  7. 根据权利要求5所述的隔膜,其中,所述第二粘结剂满足以下条件的其中一者:
    (c)基于所述多孔涂层的总重量,所述第二粘结剂的重量含量w 2%满足2≤w 2≤8;或
    (d)所述第二粘结剂的pH值pH 2满足3≤pH 2≤7。
  8. 根据权利要求1所述的隔膜,其中,所述第一粘结剂满足以下条件的其中一者:
    (e)所述第一粘结剂仅包含化合价为+1的所述金属元素和化合价为+2的所述金属元素,其中化合价为+1的所述金属元素与化合价为+2的所述金属元素的摩尔含量比为a,1≤a≤10;
    (f)所述第一粘结剂仅包含化合价为+1的所述金属元素和化合价为+3的所述金属元素,其中化合价为+1的所述金属元素与化合价为+3的所述金属元素的摩尔 含量比为b,1≤b≤50。
  9. 根据权利要求1所述的隔膜,其中,所述金属元素包括Li、Na、Ca、Mg或Al中的至少两种。
  10. 根据权利要求5所述的隔膜,其中,所述第一粘结剂和所述第二粘结剂中的至少一者包括羧基和/或磺酸基。
  11. 根据权利要求5所述的隔膜,其中,所述粘结剂满足以下条件中的至少一者:
    (g)所述第一粘结剂包括以下各者中的至少一种:聚甲基纤维素钠、聚甲基纤维素锂、聚羧甲基纤维素锂、聚羟丙基甲基纤维素锂、聚丙烯酸钙、聚丙烯酸锂或聚甲基丙烯酸钙;
    (h)所述第二粘结剂包括以下各者中的至少一种:聚丙烯酸丁酯、聚丙烯酸乙酯、聚甲基丙烯酸丁酯、聚甲基丙烯酸甲酯或丁苯橡胶。
  12. 根据权利要求1所述的隔膜,其中,所述无机颗粒的比表面积为8 BETm 2/g,2≤S BET≤10。
  13. 根据权利要求1所述的隔膜,其中,所述无机颗粒的中值粒径Dv50满足0.3μm≤Dv50≤2μm。
  14. 根据权利要求1所述的隔膜,其中,所述无机颗粒包括以下各者中的至少一者:三氧化二铝、勃姆石、氧化锆、氮化硼、氮化硅或氮化铝。
  15. 根据权利要求1所述的隔膜,其中,所述多孔涂层还包括润湿剂,其中以所述多孔涂层的总重量计,所述无机颗粒的重量含量为m 1%,所述粘结剂的重量含量为m 2%,所述润湿剂的重量含量为m 3%,其中90≤m 1≤96,3≤m 2≤9,0.5≤m 3≤1.5,且m 1+m 2+m 3=100。
  16. 根据权利要求15所述的隔膜,其中,所述润湿剂包括以下各者中的至少一种:聚氧乙烯烷基酚醚、聚氧乙烯脂肪醇醚、聚氧乙烯聚氧丙烯嵌段共聚物或硅氧烷。
  17. 根据权利要求1所述的隔膜,其中,将所述隔膜在150℃下放置1小时,所述隔膜在MD方向上的热收缩率为L1,在TD方向上的热收缩率为L2,L1<10%,L2<10%,0.75≤L1/L2≤1.2。
  18. 根据权利要求1所述的隔膜,其中,所述隔膜满足以下条件中的至少一者:
    (i)所述隔膜的厚度为Hμm,3.5≤H≤14;
    (j)所述多孔基材的厚度为H 1μm,3≤H 1≤10;或者
    (k)所述多孔涂层的厚度为H 2μm,0.5≤H 2≤4。
  19. 根据权利要求1所述的隔膜,其中,所述多孔涂层满足以下条件中的至少一者:
    (l)所述多孔涂层的粘结力为F N/m,5≤F≤100;
    (m)所述多孔涂层的透气度为K s/100ml,5≤K≤40。
  20. 一种电化学装置,其包括权利要求1-19中任一者所述的隔膜。
  21. 一种电子装置,其包括权利要求20所述的电化学装置。
PCT/CN2022/088842 2022-04-24 2022-04-24 隔膜及包含其的装置 Ceased WO2023205968A1 (zh)

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CN202280004833.8A CN116097514B (zh) 2022-04-24 2022-04-24 隔膜及包含其的装置
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CN116097514A (zh) 2023-05-09
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US20250046950A1 (en) 2025-02-06
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