CN115966842A - Isolating membrane, secondary battery containing isolating membrane and power utilization device - Google Patents
Isolating membrane, secondary battery containing isolating membrane and power utilization device Download PDFInfo
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- CN115966842A CN115966842A CN202111179556.8A CN202111179556A CN115966842A CN 115966842 A CN115966842 A CN 115966842A CN 202111179556 A CN202111179556 A CN 202111179556A CN 115966842 A CN115966842 A CN 115966842A
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
- H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- 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
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- 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
- H01M50/446—Composite material consisting of a mixture of organic and inorganic materials
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- 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
- H01M50/449—Separators, membranes or diaphragms characterised by the material having a layered structure
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- 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
Abstract
The application provides a barrier film comprising a substrate; a coating comprising an organic-inorganic hybrid layered silicate; the organic part in the phyllosilicate comprises one or more of alkyl ammonium, quaternary ammonium salt, octadecylamine and organic silicon; the inorganic portion of the layered silicate comprises a compound represented by formula 1, M 2 (Al 2‑x Mg x )[Si 4 O 10 ](OH) 2 In formula 1, M comprises one or more of Na, li, K and Ca, and X is 0-2.
Description
Technical Field
The application relates to the technical field of batteries, in particular to an isolating membrane, a secondary battery containing the isolating membrane and an electric device.
Background
In recent years, the application range of secondary batteries has become wider and wider, and the secondary batteries are widely applied to energy storage power systems such as hydraulic power stations, thermal power stations, wind power stations and solar power stations, and a plurality of fields such as electric tools, electric bicycles, electric motorcycles, electric automobiles, military equipment and aerospace.
The safety performance of the secondary battery is always highly regarded by the industry, and therefore, how to improve the safety performance of the battery is still a problem to be solved urgently.
Disclosure of Invention
In order to achieve the above object, a first aspect of the present application provides a separator comprising: a substrate; a coating comprising an organic-inorganic hybrid layered silicate; the organic part in the phyllosilicate comprises one or more of alkyl ammonium, quaternary ammonium salt, octadecylamine and organic silicon; the inorganic portion of the layered silicate comprises a compound of formula 1, M 2 (Al 2-x Mg x )[Si 4 O 10 ](OH) 2 In the formula 1, M comprises one or more of Na, li, K and Ca, and X takes the value of 0-2.
From this, this application is through adding the phyllosilicate of specific structure in barrier film coating thick liquids, and the dispersion becomes the colloid in the solvent swelling, and simultaneously, phyllosilicate can depend on the barrier film surface after the drying, plays the effect of reinforcing barrier film mechanical strength.
In any embodiment, the organic moiety in the layered silicate comprises one or more of the compounds represented by formula 2A or formula 2B;
in formula 2A, R 11 -R 14 At least three of which are each independently selected from C 1 -C 25 Alkyl groups of (a);
in the formula 2B, R 21 Is selected from C 1 -C 25 Alkyl group of (1).
In any embodiment, R 11 -R 14 At least one of them being selected from C 10 -C 25 Alkyl groups of (a); and/or, R 21 Is selected from C 10 -C 25 Alkyl group of (1).
In any embodiment, the layered silicate is present in the coating in a proportion of 50% to 80%, optionally 60% to 70% by mass.
In any embodiment, the coating has a thickness of 3 μm or less; and optionally 0.5 μm to 3 μm.
In any embodiment, the release film has a machine direction tensile strength of 3000kgf/cm 2 -3500kgf/cm 2 。
In any embodiment, the release film has a machine direction thermal shrinkage at 150 ℃ of 3.5% to 5%.
The second aspect of the present application also provides a method for preparing a barrier film, wherein the method comprises the following steps:
step S1: providing a substrate;
step S2: providing a slurry comprising an organic-inorganic hybrid layered silicate; the organic part in the phyllosilicate comprises one or more of alkyl ammonium, quaternary ammonium salt, octadecylamine and organosilicon; the inorganic portion of the layered silicate comprises a compound of formula 1, M 2 (Al 2-x Mg x )[Si 4 O 10 ](OH) 2 In the formula 1, M comprises one or more of Na, li, K and Ca, and X takes the value of 0-2;
and step S3: the slurry is applied to at least one surface of the substrate to form a coating.
The layered silicate is formed by compounding an organic portion and an inorganic portion, and optionally, the organic portion is intercalated or exfoliated between the inorganic portions.
Therefore, the isolating membrane prepared by the method has the advantages that the layered silicate is added into the coating slurry to play a role in dispersing and thickening, and meanwhile, the dried layered silicate can be attached to the surface of the isolating membrane to play a role in enhancing the mechanical strength of the isolating membrane.
A third aspect of the present application provides a secondary battery comprising the separator of the first aspect of the present application or the separator prepared according to the method 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.
A 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.
Drawings
Fig. 1 is a schematic view of a secondary battery according to an embodiment of the present application.
Fig. 2 is an exploded view of the secondary battery according to the embodiment of the present application shown in fig. 1.
Fig. 3 is a schematic view of a battery module according to an embodiment of the present application.
Fig. 4 is a schematic diagram of a battery pack according to an embodiment of the present application.
Fig. 5 is an exploded view of the battery pack according to the embodiment of the present application shown in fig. 4.
Fig. 6 is a schematic diagram of an electric device in which a secondary battery according to an embodiment of the present application is used as a power source.
Description of reference numerals:
1, a battery pack; 2, putting the box body on the box body; 3, a lower box body; 4 a battery module; 5 a secondary battery; 51 a housing; 52 an electrode assembly; 53 a cap assembly.
Detailed Description
Embodiments of the separator, the positive electrode sheet, the negative electrode sheet, the electrolyte, the secondary battery, the battery module, the battery pack, and the electric device according to the present invention are specifically disclosed below in detail with reference to the drawings as appropriate. But a detailed description thereof will be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of actually the same structures may be omitted. This is to avoid unnecessarily obscuring the following description, and to facilitate understanding by those skilled in the art. The drawings and the following description are provided for those skilled in the art to fully understand the present application, and are not intended to limit the subject matter recited in the claims.
As disclosed herein, a "range" is defined in terms of lower and upper limits, with a given range being defined by the selection of one lower limit and one upper limit, which define the boundaries of the particular range. Ranges defined in this manner may or may not include endpoints and may be arbitrarily combined, i.e., any lower limit may be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a particular parameter, it is understood that ranges of 60-110 and 80-120 are also contemplated. Further, if the minimum range values of 1 and 2 are listed, and if the maximum range values of 3,4 and 5 are listed, the following ranges are all contemplated: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this application, unless otherwise stated, the numerical range "a-b" represents a shorthand representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, a numerical range of "0 to 5" indicates that all real numbers between "0 to 5" have been listed herein, and "0 to 5" is only a shorthand representation of the combination of these numbers. In addition, when a parameter is an integer of 2 or more, it is equivalent to disclose that the parameter is, for example, an integer of 2, 3,4, 5, 6, 7, 8, 9, 10, 11, 12, or the like.
All embodiments and alternative embodiments of the present application may be combined with each other to form new solutions, if not specifically stated.
All technical and optional features of the present application may be combined with each other to form new solutions, if not specifically mentioned.
All steps of the present application may be performed sequentially or randomly, preferably sequentially, if not specifically stated. For example, the method comprises steps (a) and (b), meaning that the method may comprise steps (a) and (b) performed sequentially, and may also comprise steps (b) and (a) performed sequentially. For example, reference to the process further comprising step (c) means that step (c) may be added to the process in any order, for example, the process may comprise steps (a), (b) and (c), may also comprise steps (a), (c) and (b), may also comprise steps (c), (a) and (b), etc.
The terms "comprises" and "comprising" as used herein mean either open or closed unless otherwise specified. For example, the terms "comprising" and "comprises" may mean that other components not listed may also be included or included, or that only listed components may be included or included.
In this application, the term "or" is inclusive, if not otherwise specified. For example, the phrase "a or B" means "a, B, or both a and B. More specifically, any one of the following conditions satisfies the condition "a or B": a is true (or present) and B is false (or not present); a is false (or not present) and B is true (or present); or both a and B are true (or present).
[ Secondary Battery ]
The secondary battery is also called a rechargeable battery or a secondary battery, and refers to a battery that can be continuously used by activating an active material by means of charging after the battery is discharged. In general, a secondary battery includes a positive electrode tab, a negative electrode tab, a separator, and an electrolyte. In the process of charging and discharging the battery, active ions (such as lithium ions) are inserted and extracted back and forth between the positive pole piece and the negative pole piece. The isolating membrane is arranged between the positive pole piece and the negative pole piece, mainly plays a role in preventing the short circuit of the positive pole and the negative pole, and can enable active ions to pass through. The electrolyte is arranged between the positive pole piece and the negative pole piece and mainly plays a role in conducting active ions.
[ isolation film ]
One embodiment of the present application provides a separator including: a substrate; a coating comprising an organic-inorganic hybrid layered silicate; the organic part in the phyllosilicate comprises one or more of alkyl ammonium, quaternary ammonium salt, octadecylamine and organic silicon; the inorganic portion of the layered silicate comprises a compound of formula 1, M 2 (Al 2-x Mg x )[Si 4 O 10 ](OH) 2 In the formula 1, M comprises one or more of Na, li, K and Ca, and X takes the value of 0-2.
The type of the substrate is not particularly limited, and any known porous structure substrate having good chemical and mechanical stability may be used.
In some embodiments, the substrate may be selected from at least one of glass fibers, non-woven fabrics, polyethylene, polypropylene, and polyvinylidene fluoride.
The application realizes compounding by adding the layered inorganic substance with a specific composition into the coating slurry of the isolating membrane, wherein the chain organic substance is intercalated or stripped among the inorganic substance layers. The obtained barrier film coating not only can enhance the mechanical property of the barrier film, but also has good dispersibility and is easy to coat. The secondary battery containing the coating isolation film has the characteristics of high safety, high capacity and long service life.
In some embodiments, the organic portion of the hybrid organic-inorganic material comprises one or more compounds of formula 2A or formula 2B,
in the formula 2A, R 11 -R 14 At least three of which are each independently selected from C 1 -C 25 Alkyl groups of (a);
in the formula 2B, R 21 Is selected from C 1 -C 25 The alkyl group of (1).
Organic-inorganic hybrids are well known in the art and are generally composites of inorganic and organic materials that are bonded at the nanoscale through intermolecular forces, hydrogen bonds, or covalent bonds. The materials mutually make up for deficiencies in performance to generate a synergistic effect, and form a material with new performance macroscopically, and a common method comprises a sol-gel method and the like. For example, the inorganic portion of the present application (e.g., na) 0.5 (Al 1.5 Mg 0.5 )[Si 4 O 10 ](OH) 2 ) The surface of organic part (such as organic ammonium salt) can be modified, and the product is prepared by stirring at a high speed in a dispersion medium containing initiator and antioxidant at a certain temperature, removing the medium by distillation, drying and crushing.
In some casesIn an embodiment, R 11 -R 14 At least one selected from C 10 -C 25 Alkyl groups of (a); and/or, said R 21 Is selected from C 10 -C 25 Alkyl group of (1).
The longer molecular chain of the organic part is beneficial to the peeling of the phyllosilicate on the microscopic scale, the composite preparation is easy to carry out when the phyllosilicate is modified, and the formed phyllosilicate has stable and high structure; and the organic matter is used as a surfactant, and the organic modified silicate formed by compounding the organic matter with silicate can have better dispersion effect in the preparation process of coating slurry.
In some embodiments, the layered silicate is present in the coating in a proportion of 50% to 80%, optionally 60% to 70% by weight. The quality ratio of the layered silicate can influence the physical characteristics of the isolating membrane and the bonding stability of the coating, and when the content is controlled in the range, the isolating membrane can ensure that the binding power is larger, the coating effect is good, the strength of the isolating membrane is higher, and the effect of enhancing the safety performance of the secondary battery is better.
In some embodiments, the coating has a thickness of 3 μm or less; and optionally 0.5 μm to 3 μm. When the thickness of the isolating film coating satisfies the range, the enhancement effect of the safety performance of the isolating film is obvious, the increase of the internal resistance of the battery cell is small, and the first effect is less.
In some embodiments, the machine direction tensile strength is 3000kgf/cm 2 -3500kgf/cm 2 。
In some embodiments, the machine direction has a heat shrinkage at 150 ℃ of 3.5% to 5%.
[ method for producing separator ]
One embodiment of the present application provides a method for preparing a separator, including the steps of:
step S1: providing a substrate;
step S2: providing slurry, wherein the slurry comprises layered silicate, and the layered silicate comprises organic-inorganic hybrid material taking the layered silicate as a main body;
wherein the organic matter is one or more of alkylammonium, quaternary ammonium salt, octadecylamine and organic silicon;
the general formula of the phyllosilicate is shown in formula 1,
M x (Al 2-x Mg x )[Si 4 O 10 ](OH) 2 in the formula 1, the raw material is shown in the specification,
in the formula 1, M comprises one or more of Na, li and K, and X takes the value of 0-2;
and step S3: and coating the slurry on at least one surface of the substrate to prepare the isolating membrane.
The layered silicate is formed by compounding an organic part and an inorganic part, and optionally, the organic matter is intercalated or stripped among the layers of the layered silicate.
The coating slurry has the characteristics of simple components, good dispersibility and high leveling property, and meanwhile, the prepared slurry is easy to coat while ensuring that the variety of materials is reduced as much as possible, and can adapt to various coating methods at present. The material is easy to dissolve in hydrocarbon solvents, and a small amount of polar solvents such as methanol, ethanol, acetone and the like are added, so that quaternary ammonium hydrocarbon chains among layered silicate layers can be bridged through hydrogen bonds to obtain effective solvation, thereby expanding and dispersing the layers, forming thixotropic gel of a card layer house structure and preventing inorganic filler from precipitating. The coating slurry is mainly used for obtaining stable slurry easy to coat, and simultaneously realizing film formation of silicate on an isolation film and enhancing the mechanical strength of the isolation film.
In some embodiments, S2 in the preparation method further comprises the steps of:
mixing and stirring an organic-inorganic hybrid material and a binder to obtain mixed solid-phase particles; adding an alcohol solvent into the mixed solid phase particles.
In some embodiments, the binder comprises one or more of polyvinylidene fluoride, polyacrylic acid, polyacrylate. The selection of the binder can influence the binding effect of the coating on the surface of the isolating membrane, wherein the polyvinylidene fluoride has better dispersion effect in the organic slurry.
In some embodiments, the alcoholic solvent includes one or more of methanol, ethanol, ethylene glycol, propanol. The alcohol solvent plays a role in enhancing the dispersion effect of the slurry in the slurry, wherein the ethanol is easy to disperse.
In some embodiments, the mass fraction ω of the layered silicate in the mixed solid phase particles 1 50-80 percent of binder in the mixed solid-phase particles 2 From 20% to 50%, optionally ω 1 /ω 2 Satisfies 1 ≤ omega 1 /ω 2 ≤4。
In some embodiments, the alcoholic solvent comprises 5% to 20% by mass of the total solvent.
In some embodiments, the slurry includes a lithium supplement agent, optionally including one or more of lithium powder or lithium oxide. In some embodiments, the method of slurry coating comprises any one of transfer coating, spray coating, die coating, gravure coating, or blade coating, or a combination of at least two thereof.
[ Positive electrode sheet ]
The positive electrode sheet generally includes a positive electrode current collector and a positive electrode film layer disposed on at least one surface of the positive electrode current collector, and the positive electrode film layer includes a positive electrode active material.
As an example, the positive electrode current collector has two surfaces opposite in its own thickness direction, and the positive electrode film layer is disposed on either or both of the two opposite surfaces of the positive electrode current collector.
In some embodiments, the positive electrode current collector may employ a metal foil or a composite current collector. For example, as the metal foil, an aluminum foil may be used. The composite current collector may include a polymer material base layer and a metal layer formed on at least one surface of the polymer material base layer. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel alloy, titanium alloy, silver alloy, etc.) on a base material of a polymer material (e.g., a base material of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
In some embodiments, the positive active material may employ a positive active material for a battery, which is well known in the art. As an example, the positive electrode active material may include at least one of the following materials: olivine structured lithium-containing phosphoric acidSalts, lithium transition metal oxides and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as a positive electrode active material of a battery may be used. These positive electrode active materials may be used alone or in combination of two or more. Among them, examples of the lithium transition metal oxide may include, but are not limited to, lithium cobalt oxide (e.g., liCoO) 2 ) Lithium nickel oxide (e.g., liNiO) 2 ) Lithium manganese oxide (e.g., liMnO) 2 、LiMn 2 O 4 ) Lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (e.g., liNi) 1/3 Co 1/3 Mn 1/3 O 2 (may also be abbreviated as NCM) 333 )、LiNi 0.5 Co 0.2 Mn 0.3 O 2 (may also be abbreviated as NCM) 523 )、LiNi 0.5 Co 0.25 Mn 0.25 O 2 (may also be abbreviated as NCM) 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O 2 (may also be abbreviated as NCM) 622 )、LiNi 0.8 Co 0.1 Mn 0.1 O 2 (may also be abbreviated as NCM) 811 ) Lithium nickel cobalt aluminum oxides (e.g., liNi) 0.85 Co 0.15 Al 0.05 O 2 ) And modified compounds thereof, and the like. Examples of olivine structured lithium-containing phosphates may include, but are not limited to, lithium iron phosphate (e.g., liFePO) 4 (also referred to as LFP for short)), a composite material of lithium iron phosphate and carbon, and lithium manganese phosphate (e.g., liMnPO) 4 ) At least one of a composite material of lithium manganese phosphate and carbon, lithium iron manganese phosphate, and a composite material of lithium iron manganese phosphate and carbon.
In some embodiments, the positive electrode film layer further optionally includes a binder. As an example, the binder may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene terpolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluoroacrylate resin.
In some embodiments, the positive electrode film layer further optionally includes a conductive agent. As an example, 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.
In some embodiments, the positive electrode sheet may be prepared by: dispersing the above components for preparing the positive electrode sheet, such as the positive electrode active material, the conductive agent, the binder and any other components, in a solvent (such as N-methylpyrrolidone) to form a positive electrode slurry; and coating the positive electrode slurry on a positive electrode current collector, and drying, cold pressing and the like to obtain the positive electrode piece.
[ negative electrode sheet ]
The negative pole piece includes the negative pole mass flow body and sets up the negative pole rete on the negative pole mass flow body at least one surface, the negative pole rete includes negative pole active material.
As an example, the negative electrode current collector has two surfaces opposite in its own thickness direction, and the negative electrode film layer is disposed on either or both of the two surfaces opposite to the negative electrode current collector.
In some embodiments, the negative electrode current collector may employ a metal foil or a composite current collector. For example, as the metal foil, copper foil can be used. The composite current collector may include a polymer base layer and a metal layer formed on at least one surface of the polymer base material. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel alloy, titanium alloy, silver alloy, etc.) on a base material of a polymer material (e.g., a base material of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).
In some embodiments, the negative active material may employ a negative active material for a battery known in the art. As an example, the anode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, lithium titanate and the like. The silicon-based material may be selected from at least one of elemental silicon, silicon oxy-compounds, silicon-carbon compounds, silicon-nitrogen compounds, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin-oxygen compounds, and tin alloys. However, the present application is not limited to these materials, and other conventional materials that can be used as a battery negative active material may also be used. These negative electrode active materials may be used alone or in combination of two or more.
In some embodiments, the anode film layer further optionally includes a binder. As an example, the binder may be selected from at least one of Styrene Butadiene Rubber (SBR), polyacrylic acid (PAA), sodium Polyacrylate (PAAs), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium Alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).
In some embodiments, the negative electrode film layer further optionally includes a conductive agent. As an example, the conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.
In some embodiments, the negative electrode film layer may also optionally include other adjuvants, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)), and the like.
In some embodiments, the negative electrode sheet can be prepared by: dispersing the components for preparing the negative electrode plate, such as a negative electrode active material, a conductive agent, a binder and any other components, in a solvent (such as deionized water) to form negative electrode slurry; and coating the negative electrode slurry on a negative electrode current collector, and drying, cold pressing and the like to obtain the negative electrode pole piece.
[ electrolyte ]
The electrolyte is not particularly limited and may be selected as desired. For example, the electrolyte may be liquid, gel, or all solid.
In some embodiments, the electrolyte is in a liquid state and includes an electrolyte salt and a solvent.
In some embodiments, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis-fluorosulfonylimide, lithium bis-trifluoromethanesulfonylimide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalato borate, lithium dioxaoxalato borate, lithium difluorooxalato phosphate, and lithium tetrafluorooxalato phosphate.
In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, propyl methyl carbonate, propyl ethyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.
In some embodiments, the electrolyte further optionally includes an additive. By way of example, the additives may include a negative electrode film-forming additive, a positive electrode film-forming additive, and may further include additives capable of improving certain properties of the battery, such as additives that improve the overcharge properties of the battery, additives that improve the high-or low-temperature properties of the battery, and the like.
In some embodiments, the positive electrode tab, the negative electrode tab, and the separator may be manufactured into an electrode assembly through a winding process or a lamination process.
In some embodiments, the secondary battery may include an exterior package. The exterior package may be used to enclose the electrode assembly and electrolyte.
In some embodiments, the outer package of the secondary battery may be a hard case, such as a hard plastic case, an aluminum case, a steel case, or the like. The outer package of the secondary battery may also be a pouch, such as a pouch-type pouch. The material of the soft bag may be plastic, and examples of the plastic include polypropylene, polybutylene terephthalate, polybutylene succinate, and the like.
The shape of the secondary battery is not particularly limited, and may be a cylindrical shape, a square shape, or any other arbitrary shape. For example, fig. 1 is a secondary battery 5 of a square structure as an example.
In some embodiments, referring to fig. 2, the overwrap may include a housing 51 and a cover plate 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 plate enclose to form an accommodating cavity. The housing 51 has an opening communicating with the accommodating chamber, and a cover plate 53 can be provided to cover the opening to close the accommodating chamber. The positive electrode tab, the negative electrode tab, and the separator may be formed into the electrode assembly 52 through a winding process or a lamination process. An electrode assembly 52 is enclosed within the receiving cavity. The electrolyte is impregnated into the electrode assembly 52. The number of the electrode assemblies 52 contained in the secondary battery 5 may be one or more, and those skilled in the art can select them according to specific practical needs.
In some embodiments, the secondary batteries may be assembled into a battery module, and the number of the secondary batteries contained in the battery module may be one or more, and the specific number may be selected by those skilled in the art according to the application and capacity of the battery module.
Fig. 3 is a battery module 4 as an example. Referring to fig. 3, in the battery module 4, a plurality of secondary batteries 5 may be arranged in series along the longitudinal direction of the battery module 4. Of course, the arrangement may be in any other way. The plurality of secondary batteries 5 may be further fixed by a fastener.
Alternatively, the battery module 4 may further include a case having an accommodation space in which the plurality of secondary batteries 5 are accommodated.
In some embodiments, the battery modules may be assembled into a battery pack, and the number of the battery modules contained in the battery pack may be one or more, and the specific number may be selected by one skilled in the art according to the application and capacity of the battery pack.
Fig. 4 and 5 are a battery pack 1 as an example. Referring to fig. 4 and 5, a battery pack 1 may include a battery case and a plurality of battery modules 4 disposed in the battery case. The battery box comprises an upper box body 2 and a lower box body 3, wherein the upper box body 2 can be covered on the lower box body 3 and forms a closed space for accommodating the battery module 4. A plurality of battery modules 4 may be arranged in any manner in the battery box.
In addition, this application still provides a power consumption device, power consumption device includes at least one in secondary battery, battery module or the battery package that this application provided. The secondary battery, the battery module, or the battery pack may be used as a power source of the electric device, and may also be used as an energy storage unit of the electric device. The powered device may include a mobile device (e.g., a mobile phone, a laptop computer, etc.), an electric vehicle (e.g., a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.), an electric train, a ship, a satellite, an energy storage system, etc., but is not limited thereto.
As the electricity-using device, a secondary battery, a battery module, or a battery pack may be selected according to the use requirement thereof.
Fig. 6 is an electric device as an example. The electric device is a pure electric vehicle, a hybrid electric vehicle or a plug-in hybrid electric vehicle and the like. In order to meet the demand of the electric device for high power and high energy density of the secondary battery, a battery pack or a battery module may be used.
[ examples ]
Hereinafter, examples of the present application will be described. The following description of the embodiments is merely exemplary in nature and is in no way intended to limit the present disclosure. The examples, where specific techniques or conditions are not indicated, are to be construed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are conventional products which are commercially available, and are not indicated by manufacturers.
Example 1
Preparation of positive pole piece
Dissolving a positive electrode active material NCM523, a conductive agent acetylene black and a binder polyvinylidene fluoride (PVDF) in a solvent N-methylpyrrolidone (NMP) according to a weight ratio of 96.5; and then uniformly coating the positive electrode slurry on a positive electrode current collector, and then drying, cold pressing and cutting to obtain the positive electrode piece.
Preparation of negative electrode plate
Dissolving active substance artificial graphite, a conductive agent acetylene black, a binder Styrene Butadiene Rubber (SBR) and a thickener carboxymethylcellulose sodium (CMC) in solvent deionized water according to a weight ratio of 95; and then uniformly coating the negative electrode slurry on a copper foil of a negative current collector, drying to obtain a negative electrode diaphragm, and performing cold pressing and slitting to obtain a negative electrode plate.
Isolation film
Preparing slurry: mixing Na 0.5 (Al 1.5 Mg 0.5 )[Si 4 O 10 ](OH) 2 The layered silicate compounded with octadecyl trimethyl ammonium bromide by a sol-gel method and a binder polyvinylidene fluoride are mixed according to the weight ratio of 40: dry mixing at 60 proportion to obtain mixed solid phase particles; adding the mixed solid phase particles into N-methylpyrrolidone, adding 8% ethanol serving as a solvent, and fully stirring in a stirring tank; adjusting the atmosphere of the stirring tank to be nitrogen atmosphere, and continuously stirring to obtain slurry;
preparing an isolating membrane: the slurry was coated on both sides of a PE substrate using gravure coating to form a coating layer, and the thickness of the single-side coating layer was 2 μm.
Preparation of the electrolyte
Ethylene Carbonate (EC), ethyl Methyl Carbonate (EMC), diethyl carbonate (DEC) were mixed in a volume ratio of 1 6 And uniformly dissolving the electrolyte in the solution to obtain the electrolyte. In the electrolyte, liPF 6 The concentration of (2) is 1mol/L.
Preparation of secondary battery
Stacking and winding the positive pole piece, the isolating membrane and the negative pole piece in sequence to obtain an electrode assembly; and (3) putting the electrode assembly into an outer package, adding the prepared electrolyte, and carrying out processes of packaging, standing, formation, aging and the like to obtain the secondary battery.
Examples 2 to 12 and comparative examples 1 to 4 were similar to the secondary battery of example 1, except that the composition of the layered silicate and the production parameters were adjusted, and the different production parameters are detailed in table 1.
Table 1: preparation parameters for examples 1 to 12 and comparative examples 1 to 3
Barrier film testing
(1) Coating material testing
The materials used in the coating can be distinguished by simple physical characterization, and comprise conventional material analysis means such as XRD crystal form confirmation, ICP element analysis and infrared organic functional group confirmation.
(2) Puncture strength test
1) Testing equipment: a high-speed rail servo control desktop tension tester (AI-3000); and (3) testing environment: normal temperature and relative humidity of 45-55%.
2) And ensuring that the surface of the sample isolation film is free of flaws, and cutting the isolation film into strips by using scissors, wherein the width of each strip of isolation film is more than 100mm.
3) A test piece with the width of 100mm is arranged on a sample membrane fixing clamping ring, then a steel needle with the diameter of 1.0mm and the diameter of 0.5mm at the top end radius is used for removing the top prick at the speed of (50 +/-5) mm/min, and the maximum load of the steel needle penetrating through the test piece is read as the puncture strength of the sample isolating membrane.
(3) Tensile Strength test
1) Testing equipment: a high-speed rail servo control desktop tension tester (AI-3000); and (3) testing environment: normal temperature and relative humidity of 45-55%.
2) The surface of the isolation film of the sample is ensured to be free of flaws, and the isolation film is cut into strips of 100mm multiplied by 15mm by scissors.
3) And fixing the isolating membrane by using a tensile machine, stretching along the length direction of the isolating membrane of the sample until the isolating membrane is broken, and recording the maximum load, namely the tensile strength of the isolating membrane.
(4) Heat shrinkage test
1) Testing equipment: a high-temperature oven; and (3) testing environment: the relative humidity is 45-55%.
2) The surface of the isolation film of the sample is ensured to be free of flaws, the isolation film is cut into square pieces of 10cm multiplied by 10cm by scissors, and the square pieces are clamped by two glass plates and put into an oven.
3) The temperature of the oven is heated to 150 ℃ at the heating rate of 5 ℃/min, and the temperature is kept for 1 hour.
4) And taking out the isolating film, cooling, and measuring the length and width shrinkage of the isolating film, wherein the ratio of the length shrinkage to the pre-heating ratio is the thermal shrinkage.
Battery testing
(1) Direct current resistance test
The test was carried out at 25 ℃ at ambient temperature.
1) After charging the cells to a nominal voltage at 1/3C (nominal capacity), constant voltage charging to a current of 0.05C or less, recording the capacity as 100% SOC; standing for 5min.
2) Constant Current discharge at 1/3C Rate 50% of the SOC electric quantity, test the voltage of the secondary cell after the adjustment is completed, recorded as V 1 。
3) Constant current continuous discharge is carried out for 10s at 4C multiplying power (corresponding to current I), the voltage of the lithium ion battery is tested after the discharge is finished, and the voltage is recorded as V 2 。
4) And calculating by using a formula to obtain direct current resistance R: r = (V) 1 -V 2 )/I。
(2) Secondary battery thermal failure temperature test
1) And (4) fully charging the electric core to a nominal voltage, then distributing temperature sensing lines, and putting the electric core into a heating furnace.
2) Heating at a heating rate of 5 ℃/min until the electric core is ignited and loses efficacy.
3) And recording the furnace temperature when the battery is invalid as the thermal invalid temperature of the battery core.
Table 2: results of Performance test of examples 1 to 12 and comparative examples 1 to 3
According to the results, the layered silicate is added into the coating of the isolating film in the examples 1 to 12, so that good effects are achieved in the aspect of the performance of the isolating film, the puncturing strength and the tensile strength of the isolating film are high, and the thermal shrinkage rate is small; in the aspect of battery performance, the battery has lower direct current resistance and enhanced safety performance while improving thermal failure temperature.
In contrast, comparative examples 1 to 3, the barrier film had poor strength and puncture strength and high heat shrinkage, and the barrier film had poor overall performance; in the aspect of battery performance, the direct current resistance is higher, the thermal failure temperature is lower, and the safety performance is poorer.
The present application is not limited to the above embodiments. The above embodiments are merely examples, and embodiments having substantially the same configuration as the technical idea and exhibiting the same operation and effect within the technical scope of the present application are all included in the technical scope of the present application. In addition, various modifications that can be conceived by those skilled in the art are applied to the embodiments and other embodiments are also included in the scope of the present application, in which some of the constituent elements in the embodiments are combined and constructed, without departing from the scope of the present application.
Claims (16)
1. A separator, comprising:
a substrate;
a coating comprising an organic-inorganic hybrid layered silicate;
the organic part in the phyllosilicate comprises one or more of alkyl ammonium, quaternary ammonium salt, octadecylamine and organic silicon,
the inorganic portion of the layered silicate comprises a compound represented by formula 1,
M 2 (Al 2-x Mg x )[Si 4 O 10 ](OH) 2 in the formula 1, the compound is shown in the specification,
in the formula 1, M comprises one or more of Na, li, K and Ca, and X takes the value of 0-2.
2. The separator of claim 1,
the organic part in the phyllosilicate comprises one or more compounds shown in a formula 2A or a formula 2B,
in formula 2A, R 11 -R 14 At least three of which are each independently selected from C 1 -C 25 Alkyl groups of (a);
in the formula 2B, R 21 Is selected from C 1 -C 25 The alkyl group of (1).
3. The separator according to claim 1 or 2,
the R is 11 -R 14 At least one selected from C 10 -C 25 Alkyl groups of (a); and/or, said R 21 Is selected from C 10 -C 25 Alkyl group of (1).
4. The separator according to any one of claims 1 to 3,
the mass of the phyllosilicate in the coating accounts for 50-80%, and 60-70% can be selected.
5. The separator of any of claims 1-4, wherein the coating has a thickness of 3 μm or less; and optionally 0.5 μm to 3 μm.
6. The release film according to any one of claims 1 to 5, wherein the release film has a longitudinal tensile strength of 3000kgf/cm 2 -3500kgf/cm 2 。
7. The release film of any of claims 1-6, wherein the release film has a machine direction heat shrinkage at 150 ℃ of 3.5% to 5%.
8. A preparation method of a separation film comprises the following steps:
step S1: providing a substrate;
step S2: providing a slurry comprising an organic-inorganic hybrid layered silicate;
the organic part in the phyllosilicate comprises one or more of alkyl ammonium, quaternary ammonium salt, octadecylamine and organic silicon;
the inorganic portion of the layered silicate comprises a compound represented by formula 1,
M 2 (Al 2-x Mg x )[Si 4 O 10 ](OH) 2 formula (II)1，
In the formula 1, M comprises one or more of Na, li, K and Ca, and X takes the value of 0-2;
and step S3: coating the slurry on at least one surface of the substrate to form a coating.
9. The production method according to claim 8, wherein the step S2 further includes:
mixing and stirring the phyllosilicate and a binder to obtain mixed solid-phase particles; adding a solvent to the mixed solid phase particles.
10. The preparation method of claim 9, wherein the binder comprises one or more of polyvinylidene fluoride, polyacrylic acid and polyacrylate.
11. The production method according to claim 9 or 10, wherein the solvent comprises an alcohol solvent; optionally, the alcohol solvent includes one or more of methanol, ethanol, ethylene glycol, and propanol.
12. Production method according to any one of claims 8 to 11, wherein the mass fraction ω of the phyllosilicate in the coating layer 1 50% -80%; can be selected to be 60-70%.
13. The production method according to any one of claims 9 to 12, wherein the mass fraction ω of the binder in the coating layer 2 20% -50%; alternatively, 1 ≦ ω 1 /ω 2 ≤4。
14. The production method according to any one of claims 9 to 13, wherein the alcohol solvent is present in the solvent in a proportion of 5% to 20% by mass.
15. A secondary battery comprising the separator of any one of claims 1 to 7 or the separator produced by the method of any one of claims 8 to 14.
16. An electric device comprising the secondary battery according to claim 15.
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| CN202111179556.8A CN115966842A (en) | 2021-10-09 | 2021-10-09 | Isolating membrane, secondary battery containing isolating membrane and power utilization device |
| PCT/CN2022/118084 WO2023056825A1 (en) | 2021-10-09 | 2022-09-09 | Isolation film, secondary battery containing same, and electrical apparatus |
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| CN116544615A (en) * | 2023-07-03 | 2023-08-04 | 宁德时代新能源科技股份有限公司 | Separator, lithium secondary battery, and electricity-using device |
| CN116526069B (en) * | 2023-07-04 | 2023-09-15 | 宁德时代新能源科技股份有限公司 | Separator, battery cell, battery and electricity utilization device |
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| JP2004256354A (en) * | 2003-02-26 | 2004-09-16 | Fuji Photo Film Co Ltd | Organic modified layered silicate and its manufacturing method, and composition and substrate containing this silicate |
| JP5664138B2 (en) * | 2010-11-08 | 2015-02-04 | ソニー株式会社 | Shrink-resistant microporous membrane, battery separator, and lithium ion secondary battery |
| CN108428838A (en) * | 2018-02-26 | 2018-08-21 | 中国东方电气集团有限公司 | A kind of preparation method of cell safety diaphragm |
| CN109037550B (en) * | 2018-07-26 | 2021-11-26 | 中科（淮安）新能源技术开发有限公司 | Method for preparing lithium battery coating diaphragm by blending organic clay mineral and polyvinylidene fluoride |
| CN109346655A (en) * | 2018-09-21 | 2019-02-15 | 江苏微能电子科技有限公司 | Over capacity stablizes lithium battery and preparation method thereof |
| EP3944361A4 (en) * | 2019-05-03 | 2022-05-18 | LG Energy Solution, Ltd. | Separator for lithium-sulfur battery, and lithium-sulfur battery comprising same |
| CN111224049A (en) * | 2020-01-14 | 2020-06-02 | 江苏厚生新能源科技有限公司 | Flame-retardant lithium battery coating diaphragm and preparation method thereof |
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| CN116581243B (en) * | 2023-07-12 | 2023-11-21 | 宁德时代新能源科技股份有限公司 | Electrode plate, preparation method thereof, secondary battery and power utilization device |
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