CN114171779A - High-safety lithium ion battery and preparation method thereof - Google Patents

High-safety lithium ion battery and preparation method thereof Download PDF

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CN114171779A
CN114171779A CN202111385959.8A CN202111385959A CN114171779A CN 114171779 A CN114171779 A CN 114171779A CN 202111385959 A CN202111385959 A CN 202111385959A CN 114171779 A CN114171779 A CN 114171779A
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electrolyte
coating
battery
preparing
lithium ion
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CN114171779B (en
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李小磊
赵珊珊
梁达
李迎
王炜娜
罗广求
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Tianjin Space Power Technology Co ltd
CETC 18 Research Institute
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Tianjin Space Power Technology Co ltd
CETC 18 Research Institute
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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
    • 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
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • H01M10/0567—Liquid materials characterised by the additives
    • 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
    • H01M10/058—Construction or manufacture
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • 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
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/417—Polyolefins
    • 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
    • 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
    • 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
    • H01M50/451—Separators, membranes or diaphragms characterised by the material having a layered structure comprising layers of only organic material and layers containing inorganic material
    • 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
    • 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
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Abstract

The invention belongs to the technical field of batteries, and particularly relates to a high-safety lithium ion battery and a preparation method thereof. The battery comprises a shell and a battery core; the battery cell comprises a positive pole piece, a diaphragm, a negative pole piece and electrolyte; the positive pole piece contains inorganic flame-retardant components, the diaphragm consists of multiple layers, one side of the substrate close to the positive pole is a coating consisting of a polymer with a gel function and a fast ion conductor, and the polymer with the gel function contains a certain flame retardant; the electrolyte contains 0.1-0.8 wt% of fluorine-containing flame retardant with the function of surfactant, 0.1-3 wt% of boron-containing additive, 0.1-3 wt% of sulfur-containing additive and 1-5 wt% of pentafluorocyclotriphosphazene additive. The battery has good safety characteristics of preventing overcharge, overdischarge, short circuit and the like, can effectively inhibit thermal runaway, improves the safety of the battery, does not influence the electrical performance of the battery, and is beneficial to the cycle performance of the battery and the like.

Description

High-safety lithium ion battery and preparation method thereof
Technical Field
The invention belongs to the technical field of batteries, and particularly relates to a high-safety lithium ion battery and a preparation method thereof.
Background
At present, although the lithium ion battery is widely applied and has a wide prospect, the lithium ion battery is determined to be a chemical power source with potential danger from the aspects of self chemical characteristics and system composition, and has a great potential safety hazard due to the existence of a plurality of factors such as mechanical abuse, electrical abuse, thermal abuse and the like in the use process.
The main measures in the prior art for solving the safety problem of the lithium ion battery are as follows: increasing internal resistance, reducing or cutting off current; flame retarding; suppressing lithium dendrites; material optimization, etc. Specifically, the method comprises the following steps:
1) the method comprises the steps of increasing internal resistance, reducing or cutting off current, and the like, wherein a safety coating with chemical degradation is coated between a current collector and a positive electrode, and a safety coating PCT with a high-temperature expansion function is coated between the current collector and the positive electrode; the safety coating with chemical degradation generally comprises a bonding substance, a conductive substance and a special sensitive substance for high temperature and high pressure, wherein the special sensitive substance is degraded under high temperature and high pressure to destroy a conductive network of the safety layer, block electron conduction, play a role in increasing internal resistance and even cutting off current and prevent thermal runaway, such as patents PCTCN2020106467, PCTCN2020106471, PCTCN2020106474 and the like; at normal temperature, the safe coating with the high-temperature expansion function forms a good conductive network, at high temperature, the high-molecular base material expands, the conductive network is blocked, the internal resistance is increased, and when the temperature reaches a certain value, the conductive network is almost blocked, and the current is cut off, such as patents CN 109167099B, CN201910731186.0, CN201910731214.9, CN201910730972.9 and the like;
2) flame retardant, mainly adding flame retardant in positive and negative electrodes and electrolyte, for example, adding nanometer resin solid flame retardant in the positive electrode of CN104835981A, adding flame retardant in the electrolyte of CN201980063342.9 and PCTCN2019121316, and the like;
3) restraining lithium dendrite, patents such as CN201811206883.6 and PCTCN2019110849 restrain lithium dendrite through electrolyte additive; CN202021766394.9 and other patents, set a barrier layer in the bending region to prevent at least a part of ions coming out from the positive electrode plate from embedding into the negative electrode plate in the bending region;
4) material optimization, including electrolyte optimization, such as PCTCN2019108606, CN201910618619.1, CN107959050A, etc.; the thermal stability of the heat insulation film is improved, such as CN 107834105B. However, increasing internal resistance, reducing or cutting off current and flame retardance are the last barriers for protecting the battery after thermal runaway of the battery, lithium dendrite inhibition is more important to safety measures at the end of battery cycle, and material optimization mainly influences the window of battery safety and is one of the bases for improving the battery safety. The safety of the battery is improved, the heat dissipation is improved, the system stability is mainly improved, the chemical heat release is reduced, and the battery is prevented from rising to the self-heating initial temperature; the temperature is prevented from further rising to the thermal runaway initiation temperature, which is a process of restraining triggering internal short circuit or a process of positive electrode oxygen evolution or thermal triggering chain reaction, and the energy release rate is slowed down; the method has the advantages that the blockage is rapidly expanded, side reactions such as oxygen evolution of the anode are inhibited, and the chain reaction of free radicals is effectively blocked, so that the last barrier for inhibiting the deep development of the thermal runaway of the lithium ion battery from the monomer perspective is a necessary measure for avoiding the fire explosion of the battery.
Disclosure of Invention
In order to solve the technical problems in the background art, the invention aims to provide a high-safety lithium ion battery and a preparation method thereof.
In order to achieve the purpose, the technical scheme of the invention is as follows:
a high-safety lithium ion battery comprises a shell and a battery core; the battery cell comprises a positive pole piece, a diaphragm, a negative pole piece and electrolyte;
the positive pole piece contains an inorganic flame-retardant component, and the inorganic flame-retardant component is one or a mixture of more of aluminum oxide, magnesium hydroxide and magnesium oxide; the particle size D50 of the inorganic flame retardant component is 1-15 microns, preferably 2-10 microns, and the content of the inorganic flame retardant component is 1-8% of that of the positive active material; the mass fraction of the positive active substance in the positive pole piece is 92-97 wt%;
the diaphragm is composed of a plurality of layers, the base material adopts a polyolefin diaphragm, one side of the base material, which is close to the anode, is provided with a coating layer composed of a polymer with a gel function and a fast ion conductor, and the polymer with the gel function contains a certain flame retardant; the side close to the negative electrode can be free of coating or selected from ceramic coating and polymer coating;
the electrolyte contains 0.1-0.8 wt% of fluorine-containing flame retardant with a surfactant function, 0.1-3 wt% of boron-containing additive, 0.1-3 wt% of sulfur-containing additive and 1-5 wt% of pentafluorocyclotriphosphazene additive.
Further, the polymer with the gel function is one of PEO, PAN, PMMA and PVDF; the macromolecular flame retardant with the gel function is one or more of potassium perfluorobutyl sulfonate and perfluoroether.
Further, the fast ion conductor is one or a mixture of garnet-structure oxide solid electrolyte particles, perovskite-structure oxide solid electrolyte particles, NASICON type solid electrolyte and LISICON type solid electrolyte.
Further, the fluorine-containing flame retardant with the surfactant function is perfluorobutyl potassium sulfonate, ammonium perfluorooctanoate and perfluoroethers, and the content of the fluorine-containing flame retardant in the electrolyte is 0.1-0.8 wt%.
Further, the boron-containing additives include, but are not limited to, boron trifluoride pyridine, trimethylboroxine, tris (trimethylsilane) borateEsters, trimethyl borate, triethyl borate, tris (pentafluorophenyl) borane, lithium dioxalate borate, lithium difluorooxalate borate, LiBF4、LiBF2(CF3)2、LiBF2(C2F5)2One or more of (a).
Further, the sulfur-containing additive comprises at least one of 1, 3-propane sultone, vinyl sulfate, allyl sulfate, 4-methyl vinyl sulfate, 4-ethyl vinyl sulfate, 1, 4-butane sultone, 4-propyl vinyl sulfate, phenyl cyclic sulfate and 1, 1' -sulfonyl diimidazole.
Furthermore, the preparation method of the high-safety lithium ion battery comprises the following steps:
s1, preparing a positive pole piece: preparing slurry from a positive active material, a conductive agent, a binder and an inorganic flame-retardant component magnesium oxide according to a mass ratio of 95.5:3:1.5 (1-5), and preparing a positive plate through coating, drying, rolling and slitting;
s2, preparing a negative pole piece: mixing a negative electrode active substance with a conductive agent, adding PVDF and NMP to prepare a negative electrode slurry, coating the negative electrode slurry on an aluminum foil, and preparing a negative electrode sheet through drying, rolling and slitting;
s3, preparation of electrolyte: the electrolyte solvent is prepared from EC, EMC and DEC in a mass ratio of 1:1: 1; the electrolyte is 1mol/L lithium hexafluorophosphate; adding a boron-containing additive, a sulfur-containing additive, ethoxy pentafluorocyclotriphosphazene and a fluorine-containing flame retardant into an electrolyte mixed by an electrolyte and a solvent;
s4, preparing a diaphragm:
(1) preparing a fast ion conductor dispersion liquid: dispersing a fast ion conductor in a dispersing agent, wherein the volume fraction of the fast ion conductor is 30-50%; sanding by a sand mill to ensure that the particle size D50 of the fast ion conductor is 200-500 nm;
(2) preparation of polymer solution with gel function:
fully dissolving polymer powder with gel function and a dispersing agent in a solvent to obtain a mixed solution, wherein the solvent comprises but is not limited to one or more of N-methyl pyrrolidone, dimethyl ammonium formate, dimethyl acetamide, dimethyl sulfoxide, hexamethyl phosphorphthalein amine, triethyl phosphate, trimethyl phosphate, tetramethyl glycerol and tripropylene glycol; the mass fraction of the high molecular powder in the mixed solution is 4-7 wt%; the number average molecular weight of the PVDF powder is 50-60 ten thousand;
(3) preparation of coating liquid:
mixing the polymer solution with the fast ion conductor dispersion liquid 1:1, uniformly mixing, adding a pore-forming agent under the stirring condition, and preparing coating liquid; uniformly coating the coating liquid on a base material by a micro-gravure coating method, and drying to prepare a coating with the thickness of 1-3 microns;
(4) coating a coating consisting of a polymer with a gel function and a fast ion conductor on the side of the diaphragm facing the positive electrode;
and S5, preparing the positive plate, the negative plate and the diaphragm into a battery with a required model in a winding mode, and preparing the battery into the lithium ion battery through shell filling, vacuum drying, electrolyte injection, formation and capacity grading.
The invention has the advantages and positive effects that:
1. the boron-containing additive and the sulfur-containing additive of the electrolyte in the battery provided by the invention have a synergistic effect, an SEI secondary structure can be optimized, the thermal stability of a negative electrode interface is improved, the thermal stability and the incombustibility of the electrolyte are improved by using the pentafluorocyclotriphosphazene and the fluorine-containing flame retardant with the surfactant function in a combined manner, the self-heating starting temperature of the battery is improved, the chemical heat release is reduced, and the battery is beneficial to avoiding the temperature rise of the battery to the self-heating starting temperature.
2. In the battery, the multilayer diaphragm is a coating layer consisting of high molecules with gel function and a fast ion conductor close to the positive electrode, and contains a certain flame retardant, so that the capability of blocking the positive electrode and the negative electrode at high temperature can be improved, the crosstalk of side reaction products on the positive electrode and the negative electrode is prevented, the electrode interface is optimized, the positive electrode oxygen evolution is inhibited, the thermal trigger chain reaction is blocked, and the thermal runaway trigger temperature is favorably improved.
3. In the battery, the positive pole piece contains a flame-retardant component, and the flame-retardant component is cooperated with the flame-retardant functions of the electrolyte and the diaphragm to block the free radical chain reaction caused by the positive pole; it is beneficial to block the rapid expansion of runaway.
4. The battery has good safety characteristics of preventing overcharge, overdischarge, short circuit and the like, can effectively inhibit thermal runaway, improves the safety of the battery, does not influence the electrical performance of the battery, and is beneficial to the cycle performance of the battery and the like.
Detailed Description
In order to further understand the contents, features and effects of the present invention, the following examples are illustrated and described in detail as follows:
the invention discloses a high-safety lithium ion battery, which comprises a shell and a battery cell inside the shell; the battery core is prepared by assembling a positive pole piece, a diaphragm, a negative pole piece and electrolyte;
preferably, the positive electrode plate contains an inorganic flame-retardant component, and the inorganic flame-retardant component is aluminum oxide (Al)2O3) Magnesium hydroxide (Mg (OH)2) And one or more of magnesium oxide (MgO), the particle diameter D50 of the inorganic flame-retardant component is between 1 and 15 microns, preferably between 2 and 10 microns, and the content is 1 to 8 percent of the active material of the positive electrode; the mass fraction of the positive active substance in the positive pole piece is 92-97 wt%;
preferably, the diaphragm is composed of multiple layers, the base material is a polyolefin diaphragm, preferably a PE diaphragm, and the thickness of the polyolefin diaphragm is 12-20 microns; the substrate is provided with a coating layer which is close to the anode and consists of a polymer with a gel function and a fast ion conductor, and the polymer with the gel function contains a certain flame retardant; the side close to the negative electrode may be free of coating, or alternatively, a ceramic coating, a polymer coating, or the like, preferably a ceramic coating.
The coating layer on the substrate close to the positive electrode is composed of a polymer with a gel function and a fast ion conductor, wherein the polymer with the gel function is one of PEO, PAN, PMMA, PVDF and the like, and PVDF is preferred. The macromolecular flame retardant with the gel function is one or more of potassium perfluorobutyl sulfonate, perfluoroethers and the like.
The fast ion conductor is garnet-structured oxide solid electrolyte particles (such as Li)7La3Zr2O12(LLZO), etc.), perovskite structure oxide solid electrolyte particles (e.g., Li)3XLa2/3-xTiO3(LLTO), etc.), NASICON type solid electrolyte, LISICON type solid electrolyte, preferably garnet structure oxide solid electrolyte particles (e.g., Li)7La3Zr2O12(LLZO), etc.), perovskite structure oxide solid electrolyte particles (e.g., Li)3XLa2/3-xTiO3(LLTO), etc.). In order to control the particle size distribution of the solid electrolyte in a suspension and make a slurry more uniform, a fast ion conductor needs to be added into one or more dispersing agents of tripropylene glycol, potassium fluorobutylsulfonate, perfluoroethers and the like, so that the effect of wetting is achieved in addition to dispersion, the stripping force of a coating is increased, and the adhesion between the coating and a diaphragm is increased. Preferably, the fast ion conductor in the dispersant has a particle size of 50 to 1000 nm, preferably 50 to 500 nm.
Mixing a PVDF solution with a fast ion conductor dispersion solution 1:1, uniformly mixing, adding a pore-forming agent under the stirring condition, and preparing coating liquid; adding a pore-forming agent under stirring, wherein the content of the pore-forming agent accounts for 40-60% of the mass of the PVDF.
Preferably, the electrolyte contains a fluorine-containing flame retardant with a surfactant function, a boron-containing additive and a sulfur-containing additive which are used for synergistically regulating an interface structure, namely, an interface film structure (the chemical composition, thickness, morphology and the like of a negative electrode SEI) formed in a chemical formation process of a positive electrode and a negative electrode is mainly regulated, the chemical composition, thickness, morphology and the like of a positive electrode CEI film are regulated, and the thermal stability and the ion and electron transport capacity are improved.
Preferably, the fluorine-containing flame retardant with the surfactant function is potassium perfluorobutyl sulfonate, ammonium perfluorooctanoate, perfluoroethers and the like, preferably potassium perfluorobutyl sulfonate, and the content of the potassium perfluorobutyl sulfonate in the electrolyte is 0.1 to 0.8wt per thousand.
The boron-containing additives include, but are not limited to, pyridine boron trifluoride (PBF) TMSB, Trimethylboroxine (TMB), tris (trimethylsilane) borate (TMSB), Trimethyl Borate (TB), triethyl borate (TEB), tris (pentafluorophenyl) borane ((C6F5)3B, TPFPB), lithium bis (LiBOB) oxalate, boron difluoro (B) oxalateLithium acid (LiDFOB) and LiBF4、 LiBF2(CF3)2、LiBF2(C2F5)2Etc. in an amount of 0.1 to 3 wt% in the electrolyte;
the sulfur-containing additive comprises at least one of 1, 3-Propane Sultone (PS), vinyl sulfate (DTD), allyl sulfate, 4-methyl vinyl sulfate (MDTD), 4-ethyl vinyl sulfate, 1, 4-Butane Sultone (BS), 4-propyl vinyl sulfate, cyclic phenyl sulfate, 1' -sulfonyl diimidazole and the like, and the content of the sulfur-containing additive in the electrolyte is 0.1-3 wt%;
the pentafluorocyclotriphosphazene additive and the fluorine-containing flame retardant with the surfactant function in the electrolyte synergistically retard flame and improve the thermal stability of the electrolyte, and the content of the pentafluorocyclotriphosphazene additive in the electrolyte is 1-5 wt%;
the following examples are provided to illustrate the preparation of high safety lithium ion batteries in detail:
example 1
A preparation method of a high-safety lithium ion battery comprises the following steps:
s1, preparing a positive pole piece: preparing slurry from lithium cobaltate, a conductive agent SP, a binder polyvinylidene fluoride and an inorganic flame-retardant component magnesium oxide according to the mass ratio of 95.5:3:1.5:5, and preparing a positive plate through coating, drying, rolling and slitting;
s2, preparing a negative pole piece: mixing 9g of graphite and 0.5g of conductive agent SP, adding 0.5g of PVDF and 40ml of NMP to prepare negative electrode slurry, coating the negative electrode slurry on an aluminum foil, and preparing a negative electrode sheet through drying, rolling and slitting;
s3, preparation of electrolyte: the electrolyte solvent is prepared from EC, EMC and DEC in a mass ratio of 1:1: 1; the electrolyte is 1mol/L lithium hexafluorophosphate; adding 3% of lithium difluoro (oxalato) borate (LiDFOB), 3% of vinyl sulfate (DTD), 5% of ethoxy pentafluorocyclotriphosphazene and 0.8% of potassium perfluorobutylsulfonate into an electrolyte mixed by an electrolyte and a solvent;
s4, preparing a diaphragm:
(1) preparing a fast ion conductor dispersion liquid: dispersing a fast ion conductor in one or more of tripropylene glycol, potassium fluorobutylsulfonate, perfluoroethers and the like as a dispersing agent, wherein the volume fraction of the fast ion conductor is 30-50%; sanding by a sand mill to ensure that the particle size D50 of the fast ion conductor is 200-500 nm;
(2) preparation of PVDF solution:
since PVDF has low surface energy and is not well matched with the surfaces of solid electrolyte and polyolefin membrane, it is necessary to sufficiently dissolve PVDF powder and dispersant cellulose ether in a solvent to obtain a mixed solution, wherein the solvent includes, but is not limited to, one or more of N-methyl pyrrolidone (NMP), dimethyl formamide (DMF), dimethyl acetamide (DMAC), dimethyl sulfoxide (DMSO), hexamethyl phosphorphthalein amine (HMPA), triethyl phosphate (TEP), trimethyl phosphate (TMP), tetramethyl diamine (TMU), tripropylene glycol, and the like, preferably NMP; the mass fraction of the PVDF powder in the mixed solution is 4-7 wt%; the number average molecular weight of the PVDF powder is 50-60 ten thousand;
(4) preparation of coating liquid:
mixing a PVDF solution with a fast ion conductor dispersion solution 1:1, uniformly mixing, adding a pore-forming agent under the stirring condition, and preparing coating liquid; uniformly coating the coating liquid on a base material by a micro-gravure coating method, and drying to prepare a coating with the thickness of 1-3 microns;
(4) the diaphragm adopts a 12-micron PE base film, a coating consisting of a polymer with a gel function and a fast ion conductor is coated towards the positive electrode side, the thickness of the coating is 2 microns, and the negative electrode side is coated with a water-based ceramic coating, the thickness of the coating is 2 microns;
and S5, preparing the positive plate, the negative plate and the diaphragm into a battery with a required model in a winding mode, and preparing the battery into the lithium ion battery through the working procedures of casing, vacuum drying, electrolyte injection, formation, capacity grading and the like. The battery capacity was 10 Ah.
Example 2
In the embodiment, lithium cobaltate, a conductive agent SP, a binder polyvinylidene fluoride and an inorganic flame-retardant component magnesium oxide are configured according to a mass ratio of 95.5:3:1.5: 1; except for the above, a lithium ion battery was manufactured in the same manner as in example 1.
Example 3
In this example, 1% lithium difluorooxalato borate (liddob), 1% vinyl sulfate (DTD), 3% ethoxypentafluorocyclotriphosphazene, and 0.5% potassium perfluorobutylsulfonate were added to the electrolyte solvent;
except for the above, a lithium ion battery was manufactured in the same manner as in example 1.
Example 4
In this example, 0.1% lithium difluorooxalato borate (liddob), 0.1% vinyl sulfate (DTD), 1% ethoxypentafluorocyclotriphosphazene, 0.1% potassium perfluorobutylsulfonate (pflsulfate) were added to the electrolyte solvent; except for the above, a lithium ion battery was manufactured in the same manner as in example 1.
Comparative example 1
In this example, the addition ratio of the inorganic flame retardant component, magnesium oxide, in the positive electrode was 0; except for the above, a lithium ion battery was manufactured in the same manner as in example 1.
Comparative example 2
In this example, 0% lithium difluorooxalato borate (liddob), 0% vinyl sulfate (DTD), 0% ethoxypentafluorocyclotriphosphazene, and 0% potassium perfluorobutylsulfonate were added to the electrolyte solvent; except for the above, a lithium ion battery was manufactured in the same manner as in example 1.
Comparative example 3
In the embodiment, the base film in the diaphragm is made of PE with the thickness of 12 microns, and the single surface of the base film is coated with a 2-micron water-based ceramic coating; except for the above, a lithium ion battery was manufactured in the same manner as in example 1.
The batteries of examples 1-4 and comparative examples 1-3 were subjected to needle punching, pressing and hot box tests, the test results of which are shown in table 1:
TABLE 1 test results
Figure RE-GDA0003434357190000071
As seen from table 1, the batteries of examples 1-4 all passed the needle punching, pressing and hot box tests.
As can be seen from a comparison of example 1 and comparative example 1, it is demonstrated that the addition of a surfactant and a PE binder has an important influence on the thermal stability and electrochemical stability of the separator, and a surfactant resistant to heat and oxidation is preferable.
As can be seen from the comparison between example 1 and comparative example 1, the positive electrode sheet contains a flame retardant component, which has a positive effect on improving the safety of the battery.
It can be seen from the comparison between example 1 and comparative example 2 that the positive electrode plate contains a flame retardant component, the electrolyte contains a boron additive and a sulfur additive in a synergistic effect, and the safety of the battery can be obviously improved by using the combination of the pentafluorocyclotriphosphazene and the fluorine-containing flame retardant with the function of the surfactant.
As can be seen from the comparison between example 1 and comparative example 3, the coating layer close to the positive electrode has the gel functional polymer and the fast ion conductor, so that the free radical chain reaction can be effectively blocked, the runaway rapid expansion can be blocked, and the safety of the battery can be obviously improved.
The embodiments described herein are only some, and not all, embodiments of the invention. Based on the above explanations and guidance, those skilled in the art can make modifications, improvements, substitutions, and the like on the embodiments based on the present invention and examples, but all other embodiments obtained without innovative research fall within the scope of the present invention.

Claims (7)

1. A high-safety lithium ion battery comprises a shell and a battery core; the battery cell comprises a positive pole piece, a diaphragm, a negative pole piece and electrolyte;
the method is characterized in that: the positive pole piece contains an inorganic flame-retardant component, and the inorganic flame-retardant component is one or a mixture of more of aluminum oxide, magnesium hydroxide and magnesium oxide; the particle size D50 of the inorganic flame-retardant component is between 1 and 15 microns, and the content of the inorganic flame-retardant component is 1 to 8 percent of that of the positive active substance; the mass fraction of the positive active substance in the positive pole piece is 92-97 wt%;
the diaphragm is composed of a plurality of layers, the base material adopts a polyolefin diaphragm, one side of the base material, which is close to the anode, is provided with a coating layer composed of a polymer with a gel function and a fast ion conductor, and the polymer with the gel function contains a certain flame retardant; the side close to the negative electrode can be free of coating or selected from ceramic coating and polymer coating;
the electrolyte contains 0.1-0.8 wt% of fluorine-containing flame retardant with a surfactant function, 0.1-3 wt% of boron-containing additive, 0.1-3 wt% of sulfur-containing additive and 1-5 wt% of pentafluorocyclotriphosphazene additive.
2. The high-safety lithium ion battery according to claim 1, wherein: the polymer with the gel function is one of PEO, PAN, PMMA and PVDF; the macromolecular flame retardant with the gel function is one or more of potassium perfluorobutyl sulfonate and perfluoroether.
3. The high-safety lithium ion battery according to claim 1, wherein: the fast ion conductor is one or a mixture of garnet-structure oxide solid electrolyte particles, perovskite-structure oxide solid electrolyte particles, NASICON-type solid electrolyte and LISICON-type solid electrolyte.
4. The high-safety lithium ion battery according to claim 1, wherein: the fluorine-containing flame retardant with the function of the surfactant is perfluorobutyl potassium sulfonate, ammonium perfluorooctanoate and perfluoroether, and the content of the fluorine-containing flame retardant in the electrolyte is 0.1-0.8wt per mill.
5. The high-safety lithium ion battery according to claim 1, wherein: the boron-containing additives include, but are not limited to, boron trifluoride pyridine, trimethylboroxine, tris (trimethylsilane) borate, trimethyl borate, triethyl borate, tris (pentafluorophenyl) borane, lithium bis (oxalato) borate, lithium difluoro (oxalato) borate, LiBF4、LiBF2(CF3)2、LiBF2(C2F5)2One or more of (a).
6. The high-safety lithium ion battery according to claim 1, wherein: the sulfur-containing additive comprises at least one of 1, 3-propane sultone, vinyl sulfate, allyl sulfate, 4-methyl vinyl sulfate, 4-ethyl vinyl sulfate, 1, 4-butane sultone, 4-propyl vinyl sulfate, phenyl cyclic sulfate and 1, 1' -sulfonyl diimidazole.
7. The method for producing a high-safety lithium ion battery according to any one of claims 1 to 6, wherein: the method comprises the following steps:
s1, preparing a positive pole piece: preparing slurry from a positive active material, a conductive agent, a binder and an inorganic flame-retardant component magnesium oxide according to a mass ratio of 95.5:3:1.5 (1-5), and preparing a positive plate through coating, drying, rolling and slitting;
s2, preparing a negative pole piece: mixing a negative electrode active substance with a conductive agent, adding PVDF and NMP to prepare a negative electrode slurry, coating the negative electrode slurry on an aluminum foil, and preparing a negative electrode sheet through drying, rolling and slitting;
s3, preparation of electrolyte: the electrolyte solvent is prepared from EC, EMC and DEC in a mass ratio of 1:1: 1; the electrolyte is 1mol/L lithium hexafluorophosphate; adding a boron-containing additive, a sulfur-containing additive, ethoxy pentafluorocyclotriphosphazene and a fluorine-containing flame retardant into an electrolyte mixed by an electrolyte and a solvent;
s4, preparing a diaphragm:
(1) preparing a fast ion conductor dispersion liquid: dispersing a fast ion conductor in a dispersing agent, wherein the volume fraction of the fast ion conductor is 30-50%; sanding by a sand mill to ensure that the particle size D50 of the fast ion conductor is 200-500 nm;
(2) preparation of polymer solution with gel function:
fully dissolving polymer powder with gel function and a dispersing agent in a solvent to obtain a mixed solution, wherein the solvent comprises but is not limited to one or more of N-methyl pyrrolidone, dimethyl ammonium formate, dimethyl acetamide, dimethyl sulfoxide, hexamethyl phosphorphthalein amine, triethyl phosphate, trimethyl phosphate, tetramethyl glycerol and tripropylene glycol; the mass fraction of the high molecular powder in the mixed solution is 4-7 wt%; the number average molecular weight of the PVDF powder is 50-60 ten thousand;
(3) preparation of coating liquid:
mixing the polymer solution with the fast ion conductor dispersion liquid 1:1, uniformly mixing, adding a pore-forming agent under the stirring condition, and preparing coating liquid; uniformly coating the coating liquid on a base material by a micro-gravure coating method, and drying to prepare a coating with the thickness of 1-3 microns;
(4) coating a coating consisting of a polymer with a gel function and a fast ion conductor on the side of the diaphragm facing the positive electrode;
and S5, preparing the positive plate, the negative plate and the diaphragm into a battery with a required model in a winding mode, and preparing the battery into the lithium ion battery through shell filling, vacuum drying, electrolyte injection, formation and capacity grading.
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Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017015996A1 (en) * 2015-07-28 2017-02-02 东莞市凯欣电池材料有限公司 Phosphonitrile fluoroalkyl sulfimide alkali metal salt and electrolyte solution containing the metal salt
CN106450442A (en) * 2016-09-27 2017-02-22 湖南杉杉能源科技股份有限公司 Flame-retardant gel electrolyte for lithium-ion battery and preparation method of flame-retardant gel electrolyte, and preparation method of lithium-ion battery
WO2017190355A1 (en) * 2016-05-06 2017-11-09 深圳先进技术研究院 Electrolyte solution, secondary battery containing electrolyte solution and preparation method therefor
CN107645013A (en) * 2016-07-22 2018-01-30 中国科学院物理研究所 Compound quasi-solid electrolyte, its preparation method and the lithium battery or lithium ion battery containing it
CN108305976A (en) * 2018-02-01 2018-07-20 中航锂电技术研究院有限公司 A kind of lithium-ion-power cell and its diaphragm
CN108400336A (en) * 2018-03-17 2018-08-14 东华理工大学 A kind of high-safety polymer lithium ion battery anode glue size and preparation method thereof and lithium ion battery
CN108923066A (en) * 2018-06-29 2018-11-30 南通新宙邦电子材料有限公司 A kind of lithium ion battery flame-retardant electrolyte
CN109841908A (en) * 2018-12-20 2019-06-04 上海力信能源科技有限责任公司 A kind of high flame retardant preparation method of lithium ion battery
JP2020136125A (en) * 2019-02-21 2020-08-31 時空化学株式会社 Polymer ceramic composite electrolyte membrane
CN111952668A (en) * 2020-08-13 2020-11-17 梅州市量能新能源科技有限公司 Electrolyte, lithium ion battery and preparation method thereof

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2017015996A1 (en) * 2015-07-28 2017-02-02 东莞市凯欣电池材料有限公司 Phosphonitrile fluoroalkyl sulfimide alkali metal salt and electrolyte solution containing the metal salt
WO2017190355A1 (en) * 2016-05-06 2017-11-09 深圳先进技术研究院 Electrolyte solution, secondary battery containing electrolyte solution and preparation method therefor
CN107645013A (en) * 2016-07-22 2018-01-30 中国科学院物理研究所 Compound quasi-solid electrolyte, its preparation method and the lithium battery or lithium ion battery containing it
CN106450442A (en) * 2016-09-27 2017-02-22 湖南杉杉能源科技股份有限公司 Flame-retardant gel electrolyte for lithium-ion battery and preparation method of flame-retardant gel electrolyte, and preparation method of lithium-ion battery
CN108305976A (en) * 2018-02-01 2018-07-20 中航锂电技术研究院有限公司 A kind of lithium-ion-power cell and its diaphragm
CN108400336A (en) * 2018-03-17 2018-08-14 东华理工大学 A kind of high-safety polymer lithium ion battery anode glue size and preparation method thereof and lithium ion battery
CN108923066A (en) * 2018-06-29 2018-11-30 南通新宙邦电子材料有限公司 A kind of lithium ion battery flame-retardant electrolyte
CN109841908A (en) * 2018-12-20 2019-06-04 上海力信能源科技有限责任公司 A kind of high flame retardant preparation method of lithium ion battery
JP2020136125A (en) * 2019-02-21 2020-08-31 時空化学株式会社 Polymer ceramic composite electrolyte membrane
CN111952668A (en) * 2020-08-13 2020-11-17 梅州市量能新能源科技有限公司 Electrolyte, lithium ion battery and preparation method thereof

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