WO2012053286A1 - Séparateur d'élément électrochimique, procédé pour le fabriquer, électrode pour élément électrochimique, élément électrochimique - Google Patents

Séparateur d'élément électrochimique, procédé pour le fabriquer, électrode pour élément électrochimique, élément électrochimique Download PDF

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WO2012053286A1
WO2012053286A1 PCT/JP2011/070050 JP2011070050W WO2012053286A1 WO 2012053286 A1 WO2012053286 A1 WO 2012053286A1 JP 2011070050 W JP2011070050 W JP 2011070050W WO 2012053286 A1 WO2012053286 A1 WO 2012053286A1
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separator
resin
electrochemical element
volume
electrochemical
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PCT/JP2011/070050
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English (en)
Japanese (ja)
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中村祐介
児島映理
片山秀昭
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日立マクセルエナジー株式会社
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Priority to CN2011800505053A priority Critical patent/CN103229330A/zh
Priority to JP2012539635A priority patent/JPWO2012053286A1/ja
Publication of WO2012053286A1 publication Critical patent/WO2012053286A1/fr

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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
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/403—Manufacturing processes of separators, membranes or diaphragms
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
    • H01M50/409—Separators, membranes or diaphragms characterised by the material
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/417—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
    • H01M50/411—Organic material
    • H01M50/414—Synthetic resins, e.g. thermoplastics or thermosetting resins
    • H01M50/42—Acrylic resins
    • 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
    • H01M50/431—Inorganic material
    • 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
    • H01M50/489—Separators, membranes, diaphragms or spacing elements inside the cells, characterised by their physical properties, e.g. swelling degree, hydrophilicity or shut down properties
    • H01M50/491—Porosity
    • 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

Definitions

  • the present invention relates to an electrochemical element separator excellent in dimensional stability at high temperature and short circuit resistance during bending, a method for producing the same, an electrode for electrochemical element integrated with the separator, and the separator for electrochemical element
  • the present invention relates to an electrochemical element that is safe even in a high temperature environment.
  • Electrochemical elements using non-aqueous electrolytes such as lithium secondary batteries and non-aqueous electrolytes typified by supercapacitors are characterized by high energy density, and are used in mobile devices such as mobile phones and notebook personal computers. It is widely used as a power source, and there is a tendency that the capacity of the electrochemical device is further increased along with the improvement of the performance of the portable device, and ensuring further safety is an important issue.
  • a polyolefin-based porous film having a thickness of about 20 to 30 ⁇ m is used as a separator interposed between a positive electrode and a negative electrode.
  • a complicated process such as biaxial stretching or extraction of a pore opening agent is used in order to open fine and uniform holes, and the cost is high.
  • separators are expensive.
  • the constituent resin of the separator is melted below the abnormal heat generation temperature of the battery to close the pores, thereby increasing the internal resistance of the battery and improving the safety of the battery in the event of a short circuit.
  • polyethylene having a melting point of about 120 to 140 ° C. is used.
  • meltdown in which the melted polyethylene easily flows and the separator breaks may occur. In such a case, there is a risk that the positive and negative electrodes are in direct contact and the temperature further increases.
  • Patent Document 1 discloses a separator using a wholly aromatic polyamide microporous film
  • Patent Document 2 discloses a separator using a polyimide porous film
  • Patent Document 3 discloses a technique related to a separator using a polyamide nonwoven fabric
  • Patent Document 4 discloses a technique related to a separator based on a nonwoven fabric using aramid fibers.
  • a heat-resistant microporous membrane or nonwoven fabric is used, the cost of the material or difficulty in manufacturing becomes a problem.
  • Patent Document 5 discloses a technique relating to a separator having a porous inorganic coating on and in a polymer nonwoven fabric substrate. Since such a separator employs an inorganic coating that is excellent in heat resistance but lacks flexibility, when applied to an electrochemical element using a wound body, there is a risk that a crack will occur due to bending and a short circuit may occur. . In particular, in an electrochemical element using a flat wound body such as a square battery, intense bending occurs, and thus such a separator is very difficult to apply.
  • the present invention has been made in view of the above circumstances, and provides an electrochemical element excellent in reliability and safety at high temperatures, a separator that can constitute the electrochemical element, and a method for manufacturing the same.
  • the separator for an electrochemical element of the present invention is a separator for an electrochemical element that is formed by photopolymerization and includes a resin A having a cross-linked structure and electrically insulating inorganic fine particles B, except for the pore volume,
  • the ratio a / b between the volume a of the resin A and the volume b of the inorganic fine particles B is 0.6 to 9.
  • the method for producing an electrochemical element separator of the present invention is the method for producing an electrochemical element separator of the present invention, wherein the volatile material is formed from a sheet for forming an electrochemical element separator containing a volatile substance.
  • the electrochemical element electrode of the present invention is characterized by being integrated with the electrochemical element separator of the present invention.
  • the electrochemical element of the present invention is an electrochemical element including a positive electrode, a negative electrode, a separator, and a non-aqueous electrolyte, wherein the separator is the separator for an electrochemical element of the present invention.
  • the reliability of the electrochemical device and the safety at high temperatures can be improved.
  • FIG. 1A is a plan view showing an example of an electrochemical element (non-aqueous electrolyte secondary battery) of the present invention
  • FIG. 1B is a cross-sectional view of FIG. 1A
  • FIG. 2 is a perspective view showing an example of the electrochemical element of the present invention.
  • the separator for an electrochemical element of the present invention (hereinafter simply referred to as “separator”) is used for a separator of an electrochemical element having a non-aqueous electrolyte, and is formed by photopolymerization and has a crosslinked structure at least partially.
  • the ratio a / b of the volume of the resin A to a (volume excluding the void volume) and the volume of the inorganic fine particles B to b (volume excluding the void volume) is 0. .6 or more and 9 or less.
  • the separator of the present invention by optimizing the composition ratio of the resin A and the inorganic fine particles B, the flexibility of the separator, the mechanical strength and the heat shrinkability can be ensured satisfactorily. It is supposed that an electrochemical element excellent in safety at a high temperature can be constituted.
  • a wound electrode group especially a prismatic battery
  • a separator with excellent short-circuit resistance that can suppress the occurrence of defects such as cracks even when it is bent as in the case of a flat wound body electrode group) It is said.
  • the separator of the present invention uses a resin having a high flexibility, even a separator formed by coating on an electrode is not contracted by the separator, and further, a roll-to-roll separator. In the manufacturing process, there are no defects such as cracks, and the productivity is excellent.
  • the separator of the present invention by setting the a / b value to 9 or less, preferably 8 or less, the function of the inorganic fine particles B can be effectively extracted, and the dimensional stability at high temperature is improved.
  • the separator is excellent in heat-shrinkage resistance and has excellent short-circuit resistance by ensuring high strength (mechanical strength) and the like.
  • the electrochemical element of the present invention constituted by using the separator of the present invention having these functions has good reliability and safety at high temperatures.
  • the volume a of the resin A is a value calculated from the density of the resin A and the mass of the resin A in the separator
  • the volume b of the inorganic fine particles B is the density of the inorganic fine particles B and the separator. It is a value calculated from the mass of the inorganic fine particles B.
  • the resin A according to the separator of the present invention is formed by photopolymerization. With such a resin A, the separator can be manufactured easily and the manufacturing time can be shortened, so that the productivity of the separator can be increased.
  • resin A has a melting temperature and a glass transition temperature measured using a differential scanning calorimeter (DSC) in accordance with the provisions of Japanese Industrial Standard (JIS) K 7121.
  • DSC differential scanning calorimeter
  • the glass transition temperature of the resin A is preferably 0 ° C. or lower, and more preferably ⁇ 10 ° C. or lower.
  • the melting temperature of the resin A is preferably 80 ° C. or higher, and more preferably 100 ° C. or higher.
  • Such resin A examples include those formed by photopolymerization of known monomers and oligomers. Specifically, for example, an acrylic resin formed from an acrylic resin monomer [alkyl (meth) acrylate such as methyl methacrylate and methyl acrylate and derivatives thereof] and oligomers thereof and a crosslinking agent; urethane acrylate and a crosslinking agent And a crosslinked resin formed from an epoxy acrylate and a crosslinking agent.
  • the crosslinking agent includes dioxane glycol diacrylate, tricyclodecane dimethanol diacrylate, ethylene oxide modified trimethylolpropane triacrylate, dipentaerythritol pentaacrylate, caprolactone modified dipentaerythritol hexaacrylate.
  • Divalent or polyvalent acrylic monomers such as ⁇ -caprolactone-modified dipentaerythritol hexaacrylate can be used.
  • the resin A includes a crosslinked resin derived from an unsaturated polyester resin formed by photopolymerization from a mixture of an ester composition prepared by condensation polymerization of a divalent or polyvalent alcohol and a dicarboxylic acid and a styrene monomer; Resins formed by photopolymerization from polyfunctional epoxy, polyfunctional oxetane or a mixture thereof; various polyurethane resins produced by photopolymerization reaction of polyisocyanate and polyol; and the like can also be used.
  • polyfunctional epoxy examples include ethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, glycerol polyglycidyl ether, sorbitol glycidyl ether, and 3,4-epoxycyclohexane.
  • examples include hexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate and 1,2: 8,9 diepoxy limonene.
  • polyfunctional oxetane examples include 3-ethyl-3 ⁇ [(3-ethyloxetane-3-yl) methoxy] methyl ⁇ oxetane and xylene bisoxetane.
  • examples of the polyisocyanate include hexamethylene diisocyanate, phenylene diisocyanate, toluene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI) or bis- (4-isocyanatocyclohexyl). Examples include methane.
  • polyether polyol, polycarbonate polyol, polyester polyol etc. are mentioned, for example.
  • a monofunctional monomer such as isobornyl acrylate, methoxy polyethylene glycol acrylate, or phenoxy polyethylene glycol acrylate can be used in combination.
  • a resin A having a better balance between flexibility and strength can be formed.
  • the inorganic fine particles B according to the separator of the present invention are components that contribute to improvement of short circuit resistance by increasing the strength and dimensional stability of the separator. Further, the inorganic fine particles B can easily control the porosity and the pore diameter of the separator.
  • the inorganic fine particles B have electrical insulating properties and heat resistance that does not react and deform at temperatures of 150 ° C. or higher, and are used in the production of non-aqueous electrolytes and separators in electrochemical devices (described later). As long as it is electrochemically stable and resistant to oxidation and reduction within the operating voltage range of the electrochemical element, there is no particular limitation.
  • the inorganic fine particles B include inorganic oxide fine particles such as iron oxide, silica (SiO 2 ), alumina (Al 2 O 3 ), TiO 2 (titania), BaTiO 3 ; inorganic nitride such as aluminum nitride and silicon nitride.
  • inorganic oxide fine particles such as calcium fluoride, barium fluoride, barium sulfate, and the like; insoluble crystal particles such as silicon and diamond; clay particles such as montmorillonite;
  • the inorganic oxide fine particles may be fine particles such as boehmite, zeolite, apatite, kaolin, mullite, spinel, olivine, mica, or a mineral resource-derived material or an artificial product thereof.
  • the surface of a conductive material exemplified by a metal, SnO 2 , a conductive oxide such as tin-indium oxide (ITO) or a carbonaceous material such as carbon black or graphite, and the like has an electrically insulating material (
  • covering with the said inorganic oxide etc. may be sufficient.
  • the inorganic fine particles B those exemplified above may be used alone or in combination of two or more.
  • inorganic oxide fine particles are more preferable, and alumina, titania, silica, and boehmite are more preferable.
  • the average particle diameter of the inorganic fine particles B is preferably 0.001 ⁇ m or more, more preferably 0.1 ⁇ m or more, and preferably 15 ⁇ m or less, and preferably 1 ⁇ m or less. More preferred.
  • the average particle size of the inorganic fine particles B is, for example, the number average particle size measured by dispersing the inorganic fine particles B in a medium that does not dissolve using a laser scattering particle size distribution analyzer (for example, “LA-920” manufactured by HORIBA). Can be defined as
  • the inorganic fine particle B may have a shape close to a sphere, and may have a plate shape or a fiber shape, but from the viewpoint of improving the short circuit resistance of the separator.
  • it is preferably a plate-like particle or a particle having a secondary particle structure in which primary particles are aggregated.
  • particles having a secondary particle structure in which primary particles are aggregated are more preferable.
  • the plate-like particles and secondary particles include plate-like alumina, plate-like boehmite, secondary particle-like alumina, and secondary particle-like boehmite.
  • the resin A and the inorganic fine particles B do not use a porous substrate made of a fibrous material to be described later, it is preferable that these are the main components of the separator.
  • the total volume of A and the inorganic fine particles B is preferably 50% by volume or more, and more preferably 70% by volume or more, in the total volume of components constituting the separator (volume excluding the void portion). 100 volume% may be sufficient.
  • the total volume of the resin A and the inorganic fine particles B is the total volume of components constituting the separator (hole portion)
  • the volume is preferably 20% by volume or more, and more preferably 40% by volume or more.
  • a fibrous material may be mixed together with the resin A and the inorganic fine particles B.
  • the fibrous material has a heat-resistant temperature (temperature at which no deformation is observed during visual observation) of 150 ° C. or more, has an electrical insulating property, is electrochemically stable, and has an electrochemical element.
  • the material is not particularly limited as long as it is stable to the solvent used in the production of the non-aqueous electrolyte and the separator.
  • the “fibrous material” in the present invention means an aspect ratio [length in the long direction / width in the direction perpendicular to the long direction (diameter)] of 4 or more, and the aspect ratio Is preferably 10 or more.
  • constituent material of the fibrous material include, for example, cellulose and its modified products (carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC), etc.), polyolefin (polypropylene (PP), propylene copolymer, etc.), Polyester (polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), etc.), polyacrylonitrile (PAN), aramid, polyamideimide, polyimide and other resins; glass, alumina, zirconia, silica and other inorganic materials These constituent materials may contain 2 or more types.
  • the fibrous material may contain various known additives (for example, an antioxidant in the case of a resin) as necessary.
  • the diameter of the fibrous material may be equal to or less than the thickness of the separator, but is preferably 0.01 to 5 ⁇ m, for example.
  • the diameter is too large, the entanglement between the fibrous materials is insufficient, and when the base material of the separator is formed by forming a sheet-like material, the strength may be reduced and handling may be difficult.
  • the diameter is too small, the pores of the separator become too small, and the ion permeability tends to decrease, which may reduce the load characteristics of the electrochemical element.
  • the content of the fibrous material in the separator is, for example, preferably 10% by volume or more, and more preferably 20% by volume or more, among all the constituent components.
  • the content of the fibrous material in the separator is preferably 70% by volume or less, and preferably 60% by volume or less, but when used as a porous substrate described later, 90% by volume or less. It is preferable that it is 80 volume% or less.
  • the state of the presence of the fibrous material in the separator is, for example, that the angle of the long axis (long axis) with respect to the separator surface is preferably 30 ° or less on average, and more preferably 20 ° or less. .
  • the separator of the present invention preferably has a shutdown function from the viewpoint of further enhancing the safety of the electrochemical element used.
  • a thermoplastic resin having a melting point of 80 ° C. or higher and 140 ° C. or lower (hereinafter referred to as “hot-meltable resin C”) is contained, or liquid non-aqueous by heating.
  • a resin hereinafter referred to as “thermally swellable resin D”) that absorbs an electrolyte (non-aqueous electrolyte; hereinafter sometimes abbreviated as “electrolyte”) and swells and increases in degree of swelling as the temperature rises. It can be included.
  • the hot-melt resin C melts and closes the pores of the separator, or the heat-swellable resin D is inside the electrochemical element.
  • the non-aqueous electrolyte is absorbed to cause a shutdown that suppresses the progress of the electrochemical reaction.
  • the heat-meltable resin C is a resin having a melting point, that is, a melting temperature measured using DSC of 80 ° C. or higher and 140 ° C. or lower in accordance with JIS K 7121, and a melting temperature of 120 ° C. or higher. More preferably, it has electrical insulation properties, is stable to the non-aqueous electrolyte of the electrochemical element and the solvent used in the production of the separator, and is oxidized and reduced within the operating voltage range of the electrochemical element. A difficult electrochemically stable material is preferred.
  • polyethylene polyethylene
  • PP polypropylene
  • copolymerized polyolefin polyolefin derivatives (such as chlorinated polyethylene)
  • polyolefin wax petroleum wax
  • carnauba wax examples include polyethylene (PE), polypropylene (PP), copolymerized polyolefin, polyolefin derivatives (such as chlorinated polyethylene), polyolefin wax, petroleum wax, and carnauba wax.
  • the copolymer polyolefin include an ethylene-vinyl monomer copolymer, more specifically, an ethylene-propylene copolymer, an ethylene-vinyl acetate copolymer (EVA), an ethylene-methyl acrylate copolymer, and ethylene-ethyl.
  • EVA ethylene-vinyl acetate copolymer
  • An ethylene-acrylic acid copolymer such as an acrylate copolymer can be exemplified.
  • the structural unit derived from ethylene in the copolymerized polyolefin is desirably 85 mol% or more. Moreover, polycycloolefin etc. can also be used.
  • the heat-meltable resin C the above exemplified resins may be used alone or in combination of two or more.
  • the heat-meltable resin C among the materials exemplified above, PE, polyolefin wax, PP, or EVA having a structural unit derived from ethylene of 85 mol% or more is suitably used. Moreover, the heat-meltable resin C may contain various known additives (for example, antioxidants) added to the resin as necessary.
  • the heat-swellable resin D in the temperature range (approximately 70 ° C. or lower) in which the battery is normally used, the electrolytic solution is not absorbed or the amount of absorption is limited, and thus the degree of swelling is below a certain level.
  • Tc required temperature
  • a resin having such a property that it absorbs the electrolyte and swells greatly and the degree of swelling increases as the temperature rises is used.
  • a flowable electrolyte solution that is not absorbed by the heat-swellable resin D exists in the pores of the separator at a temperature lower than Tc.
  • thermal swelling there is a case where the degree of swelling increases with increasing temperature (hereinafter referred to as “thermal swelling”). ),
  • the heat-swellable resin D absorbs the electrolytic solution in the electrochemical element and swells greatly, and the swollen heat-swellable resin D closes the pores of the separator,
  • the temperature is higher than Tc, the liquid withering further proceeds due to thermal swellability, and the reaction of the battery is further suppressed, so that safety at high temperatures can be further enhanced.
  • the temperature at which the heat-swellable resin D starts to show heat-swellability is preferably 75 ° C. or higher.
  • the temperature (Tc) at which the internal resistance of the electrochemical element is increased by remarkably reducing the Li ion conductivity is about 80 ° C. This is because it can be set as described above.
  • the temperature at which the thermal swellable resin D starts to exhibit thermal swellability in order to set Tc to about 130 ° C. or lower is 125 ° C.
  • the temperature showing the thermal swellability is too high, the abnormal exothermic reaction of the active material in the electrochemical element may not be sufficiently suppressed, and the effect of improving the safety of the electrochemical element may not be sufficiently secured.
  • the conductivity of Li ions may be too low in the temperature range (about 70 ° C. or lower) of a normal electrochemical device.
  • the heat swellable resin D does not absorb the electrolyte solution as much as possible and has less swelling. This is because in an operating temperature range of an electrochemical element, for example, room temperature, the electrolyte is more likely to be held in a state where it can flow into the pores of the separator than to be taken into the heat-swellable resin D. This is because characteristics such as load characteristics are improved.
  • Electrolyte volume heat swelling resin D is absorbed at room temperature (25 ° C.) can be evaluated by the degree of swelling B R defined by the following equation represents the volume change of the thermal swelling resin D (1).
  • V 0 is the volume of the heat swelling resin D after 24 hours immersion at 25 ° C. in the electrolytic solution (cm 3)
  • V i is the thermal swelling resin before immersion in electrolyte solution
  • Each represents the volume (cm 3 ) of D.
  • the swelling degree B R of the heat-swellable resin D at room temperature (25 ° C.) is preferably 1 or less, it is less swelling due to absorption of the electrolyte solution it, i.e., B R it is desirable that the smallest possible value close to 0. Further, it is desirable that the temperature change of the degree of swelling is as small as possible on the lower temperature side than the temperature exhibiting thermal swellability.
  • the heat-swellable resin D when the heat-swellable resin D is heated to a temperature lower than the lower limit of the heat-swellable property, the amount of electrolyte absorbed increases, and in the temperature range showing the heat-swellability, Are used that increase. For example, it is measured at 120 ° C., swelling degree B T which is defined by the following formula (2) is, as 1 or higher is preferably used.
  • V 0 is the volume (cm 3 ) of the heat-swellable resin D after being immersed in an electrolytic solution at 25 ° C. for 24 hours
  • V 1 is after being immersed in the electrolytic solution at 25 ° C. for 24 hours.
  • the electrolyte solution is heated to 120 ° C., and the volume (cm 3 ) of the heat-swellable resin D after 1 hour at 120 ° C. is shown.
  • the degree of swelling of the heat-swellable resin D defined by the above formula (2) may be 10 or less because it may cause deformation of the electrochemical element if it becomes too large.
  • the degree of swelling defined by the above formula (2) is to directly measure the change in the size of the heat-swellable resin D using a method such as light scattering or image analysis of an image taken with a CCD camera. However, it can be measured more accurately using, for example, the following method.
  • a binder resin having a known degree of swelling at 25 ° C. and 120 ° C. which is defined in the same manner as in the above formulas (1) and (2), is mixed with the heat-swellable resin D in the solution or emulsion to form a slurry. It is prepared and applied onto a substrate such as a PET sheet or glass plate to produce a film, and its mass is measured. Next, the film was immersed in an electrolyte at 25 ° C. for 24 hours to measure the mass, and the electrolyte was heated to 120 ° C., and the mass after holding at 120 ° C. for 1 hour was measured. formula by (3) to (9) for calculating the swelling degree B T. In the following formulas (3) to (9), the volume increase of components other than the electrolytic solution when the temperature is raised from 25 ° C. to 120 ° C. can be ignored.
  • V i M i ⁇ W / P A (3)
  • V B (M 0 ⁇ M i ) / P B (4)
  • V C M 1 / P C ⁇ M 0 / P B (5)
  • V V M i ⁇ (1 ⁇ W) / P V (6)
  • V 0 V i + V B ⁇ V V ⁇ (B B +1) (7)
  • V D V V ⁇ (B B +1) (8)
  • B T ⁇ V 0 + V C ⁇ V D ⁇ (B C +1) ⁇ / V 0 ⁇ 1 (9)
  • V i Volume (cm 3 ) of the heat-swellable resin D before being immersed in the electrolytic solution
  • V 0 volume (cm 3 ) of the heat-swellable resin D after being immersed in the electrolyte at room temperature for 24 hours
  • V B volume of the electrolyte solution (cm 3 ) absorbed in the film after being immersed in the electrolyte solution at room temperature for 24 hours
  • V C The volume of the electrolyte solution absorbed by the film (cm) during the period from when it was immersed in the electrolyte solution at room temperature for 24 hours until the electrolyte solution was heated to 120 ° C. and further passed at 120 ° C. for 1 hour.
  • V V volume (cm 3 ) of the binder resin before being immersed in the electrolytic solution
  • V D volume of the binder resin (cm 3 ) after being immersed in the electrolytic solution at room temperature for 24 hours
  • M i mass (g) of the film before being immersed in the electrolytic solution
  • M 0 mass (g) of the film after being immersed in the electrolytic solution at room temperature for 24 hours
  • M 1 After immersing in the electrolytic solution at room temperature for 24 hours, the temperature of the electrolytic solution was raised to 120 ° C., and the mass (g) of the film after 1 hour at 120 ° C.
  • W Mass ratio of the heat-swellable resin D in the film before being immersed in the electrolytic solution
  • P A specific gravity (g / cm 3 ) of the heat-swellable resin D before being immersed in the electrolytic solution
  • P B Specific gravity of electrolyte at room temperature (g / cm 3 )
  • P C specific gravity of the electrolyte at a predetermined temperature (g / cm 3)
  • P V Specific gravity (g / cm 3 ) of the binder resin before being immersed in the electrolytic solution
  • B B degree of swelling of the binder resin after being immersed in the electrolyte at room temperature for 24 hours
  • B C is the degree of swelling of the binder resin at the time of temperature increase defined by the above formula (2).
  • V i and V 0 is determined from the said equation by the method (3) and the formula (7), can be determined swelling degree B R at room temperature using the above formula (1).
  • the electrochemical element of the present invention uses, for example, a solution obtained by dissolving a lithium salt in an organic solvent as a nonaqueous electrolyte, as in the case of conventionally known electrochemical elements (types of lithium salt and organic solvent). Details of the lithium salt concentration will be described later). Therefore, the heat-swellable resin D starts to show the above-mentioned heat-swellability when it reaches any temperature of 75 to 125 ° C. in an organic solvent solution of lithium salt. It is recommended that R and B T can swell so as to satisfy the above values.
  • the heat-swellable resin D is preferably an electrochemically stable material that has heat resistance and electrical insulation, is stable with respect to the electrolyte, and is not easily oxidized or reduced in the operating voltage range of the battery.
  • Examples of such a material include a crosslinked resin.
  • styrene resin polystyrene (PS), etc.), styrene butadiene rubber (SBR), acrylic resin (polymethyl methacrylate (PMMA), etc.), polyalkylene oxide (polyethylene oxide (PEO), etc.), fluororesin [ Polyvinylidene fluoride (PVDF) and the like] and a crosslinked product of at least one resin selected from the group consisting of these derivatives; urea resin; polyurethane; and the like.
  • the heat-swellable resin D the above exemplified resins may be used alone or in combination of two or more.
  • the heat-swellable resin D may contain various known additives that are added to the resin, for example, an antioxidant, as necessary.
  • crosslinked styrene resin a crosslinked acrylic resin, and a crosslinked fluororesin are preferable, and crosslinked PMMA is particularly preferably used.
  • the heat-swellable resin D is a resin having a Tg of about 75 to 125 ° C., considering that the temperature at which the shutdown action actually occurs is somewhat higher than the temperature at which the heat-swellable resin D starts to exhibit heat-swellability. It is considered desirable to use a crosslinked body.
  • Tg of the resin crosslinked body which is the heat-swellable resin D in this specification is a value measured using DSC in accordance with the provisions of JIS K7121.
  • the volume change accompanying the temperature change is reversible to some extent so that even if it expands due to the temperature rise, it shrinks again when the temperature is lowered.
  • a material that can be heated to 200 ° C or higher is used. You can choose. Therefore, even when heating is performed in a separator manufacturing process or the like, the resin is not dissolved or the thermal swellability of the resin is not impaired, and handling in a manufacturing process including a general heating process becomes easy.
  • the form of the heat-meltable resin C or the heat-swellable resin D (hereinafter, the heat-meltable resin C and the heat-swellable resin D may be collectively referred to as “shutdown resin”) is not particularly limited. It is preferable to use a shape having a particle diameter at the time of drying smaller than the thickness of the separator, and preferably has an average particle diameter of 1/100 to 1/3 of the thickness of the separator. Specifically, the average particle diameter is preferably 0.1 to 20 ⁇ m. When the particle diameter of the shutdown resin particles is too small, the gap between the particles becomes small, the ion conduction path becomes long, and the characteristics of the electrochemical device may be deteriorated.
  • the average particle diameter of the shutdown resin particles is determined by, for example, using a laser scattering particle size distribution analyzer (for example, “LA-920” manufactured by HORIBA) and dispersing the fine particles in a medium that does not swell the shutdown resin (for example, water). It can prescribe
  • the shutdown resin may be in a form other than the above, and may be present in a state of being laminated and integrated on the surface of another constituent element, for example, inorganic fine particles or a fibrous material. Specifically, it may exist as core-shell structured particles having inorganic fine particles as a core and a shutdown resin as a shell, or may be a multi-layered fiber having a shutdown resin on the surface of a core material. Furthermore, even if the separator is provided with a shutdown resin by forming a layer containing the shutdown resin (a layer formed only with the shutdown resin or a layer containing the shutdown resin and the binder) on one or both sides of the separator. Good.
  • the content of the shutdown resin in the separator is preferably as follows, for example, in order to make it easier to obtain the shutdown effect.
  • the volume of the shutdown resin in all the constituent components of the separator is preferably 10% by volume or more, and more preferably 20% by volume or more.
  • the volume of the shutdown resin in all the constituent components of the separator is preferably 50% by volume or less, and more preferably 40% by volume or less, from the viewpoint of securing the shape stability at high temperatures of the separator.
  • the separator of the present invention can be produced, for example, by the following methods (1) to (4).
  • the manufacturing method (1) of the separator includes monomers and oligomers for forming the resin A, a photopolymerization initiator, inorganic fine particles B, and particles of a heat-meltable resin C and a heat-swellable resin D as necessary.
  • a liquid composition in which these are dispersed in a volatile substance (volatile solvent) is prepared (monomer, oligomer, photopolymerization initiator may be dissolved in the volatile substance) ),
  • a porous substrate irradiating with light to form a separator-forming sheet, and then removing volatile substances by drying at a predetermined temperature to form pores.
  • a woven fabric composed of at least one kind of fibrous material containing the above-mentioned exemplified materials as constituent components, or a structure in which these fibrous materials are entangled with each other. Examples thereof include porous sheets such as non-woven fabrics. More specifically, non-woven fabrics such as paper, PP non-woven fabric, polyester non-woven fabric (PET non-woven fabric, PEN non-woven fabric, PBT non-woven fabric, etc.) and PAN non-woven fabric can be exemplified.
  • the volatile substance used in the liquid composition monomers and oligomers, photopolymerization initiators, those that can uniformly disperse or dissolve the inorganic fine particles B and the like are preferable, for example, aromatic hydrocarbons such as toluene, In general, organic solvents such as furans such as tetrahydrofuran and ketones such as methyl ethyl ketone and methyl isobutyl ketone are preferably used. In addition, for the purpose of controlling the interfacial tension, alcohols (ethylene glycol, propylene glycol, etc.) or various propylene oxide glycol ethers such as monomethyl acetate may be appropriately added to these solvents. In addition, water can be used as a volatile substance, and at this time, alcohols (methyl alcohol, ethyl alcohol, isopropyl alcohol, ethylene glycol, etc.) can be appropriately added to control the interfacial tension.
  • aromatic hydrocarbons such as toluene
  • organic solvents such as furans such
  • the photopolymerization initiator for example, 2,4,6-trimethylbenzoylbisphenylphosphine oxide, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methylpropiophenone, etc. should be used. Can do.
  • the amount of the photopolymerization initiator used is preferably 1 to 10 parts by mass with respect to 100 parts by mass of monomers and oligomers.
  • the solid content including monomers, oligomers, photopolymerization initiators, inorganic fine particles and the like is preferably 10 to 50% by mass, for example.
  • the separator production method (2) of the present invention comprises a monomer M or oligomer for forming the resin A, a photopolymerization initiator, inorganic fine particles B, and a material M that can be dissolved in a specific solvent X (preparation of a liquid composition).
  • a material that does not dissolve in the solvent Y used in the above) and a liquid composition (slurry or the like) in which particles of a heat-meltable resin C or a heat-swellable resin D are dispersed in the solvent Y if necessary.
  • solvent X for example, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, propylene carbonate, tetrahydrofuran, ⁇ -caprolactone and the like can be used.
  • the material M that can be dissolved in the specific solvent X for example, polyolefin resin, polyurethane resin, acrylic resin, or the like can be used. These materials are preferably used in the form of particles, for example, but the size and amount of use can be adjusted according to the porosity and pore size required for the separator.
  • the average particle size of the material is preferably 0.1 to 20 ⁇ m, and the amount used is the liquid composition
  • the total solid content in is preferably 1 to 10% by mass.
  • the same volatile substances that can be used in the liquid composition according to the production method (1) can be used.
  • the solid content of the liquid composition according to the production method (2) is preferably, for example, 10 to 50% by mass, as in the case of the production method (1).
  • the liquid composition according to the production method (2) can be controlled by using the same material as in the production method (1) to control the interfacial tension.
  • the separator production method (3) of the present invention is the same as the liquid composition according to the production method (1), which is applied on a substrate such as a film or metal foil, and irradiated with light to form a separator. In this method, after forming into a sheet, volatile substances are removed by drying at a predetermined temperature to form pores, and then peeled off from the substrate.
  • the liquid composition according to the production method (3) may contain a fibrous material, and the solid content including the fibrous material is preferably, for example, 10 to 50% by mass.
  • the separator manufacturing method (4) of the present invention is the same as the liquid composition according to the manufacturing method (2), applied on a substrate such as a film or metal foil, and irradiated with light to form a separator. After forming into a sheet, the material M is extracted with the specific solvent X to form pores, and then peeled off from the substrate.
  • the liquid composition according to the production method (4) may contain a fibrous material, and the solid content including the fibrous material is preferably, for example, 10 to 50% by mass.
  • the separator when manufacturing a separator by manufacturing method (3) or manufacturing method (4), the structure which integrated the separator and the electrode by using either the positive electrode which concerns on an electrochemical element, or a negative electrode as a base material It is good. In this case, the separator is not peeled off from the electrode serving as the base material.
  • the adhesion between the electrode mixture layer and the separator is high, so that the electrodes can be wound or laminated without peeling the separator from the electrode.
  • the highly flexible resin A is used, in the case of a non-aqueous electrolyte secondary battery using a wound body, it is possible to prevent a short circuit at the corner portion of the innermost periphery of the wound body.
  • the light irradiation conditions may be those employed in general photopolymerization. Specifically, for example, a high-pressure mercury lamp having a wavelength of 365 nm is used as an ultraviolet light source, and light irradiation is performed for 10 seconds at an irradiation intensity of 60 mW / cm 2 .
  • strength, irradiation time, etc. can be changed suitably.
  • the porosity of the separator is preferably 10% or more in order to ensure a sufficient amount of electrolyte solution and improve ion permeability in a dry state.
  • the separator porosity is preferably 70% or less in a dry state.
  • the porosity of the separator in a dry state P (%) is obtained from the thickness of the separator, the mass per area, and the density of the constituent components by using the following formula (10) to obtain the sum for each component i. Can be calculated.
  • a i ratio of component i expressed by mass%
  • ⁇ i density of component i (g / cm 3 )
  • m mass per unit area of separator (g / cm 2 )
  • t The thickness (cm) of the separator measured in a dry state.
  • the separator of the present invention is performed by a method according to JIS P 8117, and the Gurley value indicated by the number of seconds that 100 mL of air passes through the membrane under a pressure of 0.879 g / mm 2 is 10 to 300 sec. It is desirable to be. If the Gurley value is too large, the ion permeability decreases, whereas if it is too small, the strength of the separator may decrease. Further, the strength of the separator is desirably 50 g or more in terms of piercing strength using a needle having a diameter of 1 mm. If the piercing strength is too small, a short circuit may occur due to the piercing of the separator when lithium dendrite crystals are generated. By employ
  • the thickness of the separator of the present invention is preferably 5 ⁇ m or more, more preferably 6 ⁇ m or more, from the viewpoint of more reliably separating the positive electrode and the negative electrode. It is still more preferable that it is above. On the other hand, if the separator is too thick, the energy density of the battery may be reduced. Therefore, the thickness is preferably 70 ⁇ m or less, more preferably 50 ⁇ m or less, and 30 ⁇ m or less. Is more preferable. In the case of a structure in which the separator and the electrode are integrated, the thickness of the separator refers to the thickness of the separator applied to one surface of the electrode.
  • the electrochemical device of the present invention only needs to have a non-aqueous electrolyte and the separator of the present invention, and there are no particular restrictions on other configurations and structures, and conventionally known electrochemical devices Various configurations and structures adopted in the above can be applied.
  • the electrochemical device of the present invention includes non-aqueous electrolyte secondary batteries, non-aqueous electrolyte primary batteries, supercapacitors, and the like, and can be preferably applied to applications that require safety at high temperatures.
  • the electrochemical device of the present invention is a non-aqueous electrolyte secondary battery will be described in detail.
  • non-aqueous electrolyte secondary battery examples include a cylindrical shape (such as a square cylindrical shape or a cylindrical shape) using a steel can or an aluminum can as an outer can. Moreover, it can also be set as the soft package battery which used the laminated film which vapor-deposited the metal as an exterior body.
  • the positive electrode for example, one having a structure in which a positive electrode mixture layer containing a positive electrode active material, a binder, a conductive additive and the like is provided on one side or both sides of a current collector can be used.
  • the material which can occlude / release Li ion used for the conventionally known nonaqueous electrolyte secondary battery can be used.
  • a lithium-containing transition metal oxide having a layered structure represented by Li 1 + x MO 2 ( ⁇ 0.1 ⁇ x ⁇ 0.1, M: Co, Ni, Mn, Al, Mg, etc.), LiMn 2 O 4 It is possible to use a spinel structure lithium manganese oxide in which a part of the element is substituted with another element, an olivine type compound represented by LiMPO 4 (M: Co, Ni, Mn, Fe, etc.), or the like.
  • lithium-containing transition metal oxide having a layered structure examples include LiCoO 2 and LiNi 1-x Co xy Al y O 2 (0.1 ⁇ x ⁇ 0.3, 0.01 ⁇ y ⁇ 0. 2) and other oxides containing at least Co, Ni and Mn (LiMn 1/3 Ni 1/3 Co 1/3 O 2 , LiMn 5/12 Ni 5/12 Co 1/6 O 2 , LiMn 3 / 5 Ni 1/5 Co 1/5 O 2 etc.).
  • a carbon material such as carbon black is used as the conductive auxiliary agent, and a fluorine resin such as PVDF is used as the binder, and the positive electrode mixture layer is formed by a positive electrode mixture in which these materials and a positive electrode active material are mixed. , Formed on the current collector.
  • a metal foil such as aluminum, a punching metal, a net, an expanded metal, or the like can be used.
  • an aluminum foil having a thickness of 10 to 30 ⁇ m is preferably used.
  • the lead part on the positive electrode side is usually provided by leaving the exposed part of the current collector without forming the positive electrode mixture layer on a part of the current collector and forming the lead part at the time of producing the positive electrode.
  • the lead portion is not necessarily integrated with the current collector from the beginning, and may be provided by connecting an aluminum foil or the like to the current collector later.
  • the negative electrode is not particularly limited as long as it is a negative electrode used in a conventionally known non-aqueous electrolyte secondary battery, that is, a negative electrode containing a negative electrode active material capable of inserting and extracting Li ions.
  • a negative electrode active material lithium such as graphite, pyrolytic carbons, cokes, glassy carbons, fired organic polymer compounds, mesocarbon microbeads (MCMB), carbon fibers, etc. can be occluded / released.
  • MCMB mesocarbon microbeads
  • One type or a mixture of two or more types of carbonaceous materials are used.
  • elements such as Si, Sn, Ge, Bi, Sb, In and alloys thereof, compounds that can be charged and discharged at a low voltage close to lithium metal such as lithium-containing nitrides or lithium-containing oxides, or lithium metal or lithium / aluminum
  • An alloy can also be used as the negative electrode active material.
  • a negative electrode mixture in which a conductive additive (carbon material such as carbon black) or a binder (PVDF or the like) or the like is appropriately added to these negative electrode active materials, and a molded body (negative electrode) using the current collector as a core material A mixture layer) or a laminate of the above various alloys and lithium metal foils alone or on a current collector is used.
  • the current collector When a current collector is used for the negative electrode, a copper or nickel foil, a punching metal, a net, an expanded metal, or the like can be used as the current collector, but a copper foil is usually used.
  • the upper limit of the thickness is preferably 30 ⁇ m, and the lower limit is preferably 5 ⁇ m.
  • the lead portion on the negative electrode side may be formed in the same manner as the lead portion on the positive electrode side.
  • the electrode can be used in the form of a stacked electrode group in which the positive electrode and the negative electrode are stacked via the separator of the present invention, or a wound electrode group in which the electrode is wound.
  • the separator of the present invention excellent in short circuit resistance at the time of bending is used, the effect is more effective when a wound electrode group that deforms the separator is used.
  • the flat wound electrode group that strongly bends the separator a wound electrode group having a flat cross section
  • the effect is particularly remarkable.
  • non-aqueous electrolyte a solution (non-aqueous electrolyte) in which a lithium salt is dissolved in an organic solvent is used.
  • the lithium salt is not particularly limited as long as it dissociates in a solvent to form Li + ions and hardly causes side reactions such as decomposition in a voltage range used as a battery.
  • LiClO 4 , LiPF 6 , LiBF 4 , LiAsF 6 , LiSbF 6 and other inorganic lithium salts LiCF 3 SO 3 , LiCF 3 CO 2 , Li 2 C 2 F 4 (SO 3 ) 2 , LiN (CF 3 SO 2 ) 2 , LiC (CF 3 SO 2 ) 3 , LiC n F 2n + 1 SO 3 (2 ⁇ n ⁇ 7), LiN (R f OSO 2 ) 2 [wherein R f represents a fluoroalkyl group.
  • An organic lithium salt such as] can be used.
  • the organic solvent used for the non-aqueous electrolyte is not particularly limited as long as it dissolves the lithium salt and does not cause a side reaction such as decomposition in a voltage range used as a battery.
  • cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate and vinylene carbonate
  • chain carbonates such as dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate
  • chain esters such as methyl propionate
  • cyclic esters such as ⁇ -butyrolactone
  • Chain ethers such as dimethoxyethane, diethyl ether, 1,3-dioxolane, diglyme, triglyme and tetraglyme
  • cyclic ethers such as dioxane, tetrahydrofuran and 2-methyltetrahydrofuran
  • nitriles such as acetonitrile, propionitrile and methoxypropionitrile Sulf
  • the concentration of this lithium salt in the non-aqueous electrolyte is preferably 0.5 to 1.5 mol / L, more preferably 0.9 to 1.3 mol / L.
  • the electrochemical device of the present invention can be used for the same applications as conventionally known electrochemical devices.
  • Example 1 Preparation of separator> Urethane acrylate as an oligomer: 3.5 parts by mass, dipentoxylated pentaerythritol diacrylate as a monomer (crosslinking agent): 3.5 parts by mass, 2,4,6-trimethylbenzoylbisphenylphosphine as a photopolymerization initiator Oxide: 0.05 parts by mass, inorganic fine particle B boehmite (average particle size 0.6 ⁇ m): 32.95 parts by mass, and volatile substance toluene: 60 parts by mass for uniform mixing. A slurry was prepared.
  • a PET nonwoven fabric with a thickness of 12 ⁇ m is passed through the slurry, and the slurry is applied by pulling up and then passing through a gap having a predetermined interval, followed by irradiation with ultraviolet light having a wavelength of 365 nm for 10 seconds at an illuminance of 60 mW / cm 2. Then, it was dried to remove toluene, and a separator having a thickness of 16 ⁇ m was obtained.
  • a negative electrode active material-containing paste was prepared by mixing 95 parts by mass of graphite serving as the negative electrode active material and 5 parts by mass of PVDF so as to be uniform using NMP as a solvent. This paste is intermittently applied to both sides of a 10 ⁇ m thick collector made of copper foil so that the coating length is 290 mm on the front and 230 mm on the back, dried, and then calendered to a total thickness of 142 ⁇ m. The negative electrode mixture layer was adjusted in thickness and cut to a width of 45 mm to prepare a negative electrode. Then, tab attachment was performed to the exposed part of the copper foil in a negative electrode.
  • ⁇ Battery assembly> The positive electrode and the negative electrode obtained as described above were overlapped with the separator interposed therebetween and wound in a spiral shape to produce a wound body electrode group.
  • the obtained wound body electrode group is crushed into a flat shape, put into an aluminum outer can having a thickness of 4 mm, a height of 50 mm, and a width of 34 mm, and an electrolytic solution (ethylene carbonate and ethyl methyl carbonate are mixed in a volume ratio of 1: 2).
  • an electrolytic solution ethylene carbonate and ethyl methyl carbonate are mixed in a volume ratio of 1: 2.
  • FIG. 1A is a plan view of the nonaqueous electrolyte secondary battery of this example
  • FIG. 1B is a cross-sectional view of FIG. 1A
  • the positive electrode 1 and the negative electrode 2 are housed in a rectangular outer can 4 together with a non-aqueous electrolyte as a wound body electrode group 6 wound in a spiral shape through the separator 3 as described above.
  • a metal foil, an electrolytic solution, and the like as a current collector used for manufacturing the positive electrode 1 and the negative electrode 2 are not illustrated.
  • the outer can 4 is made of an aluminum alloy and constitutes the outer casing of the battery.
  • the outer can 4 also serves as a positive electrode terminal.
  • the insulator 5 which consists of a polyethylene sheet is arrange
  • the positive electrode lead body 7 and the negative electrode lead body 8 are drawn out.
  • a stainless steel terminal 11 is attached to an aluminum alloy cover plate 9 that seals the opening of the outer can 4 via a polypropylene insulating packing 10, and an insulator 12 is connected to the terminal 11.
  • a stainless steel lead plate 13 is attached.
  • the cover plate 9 is inserted into the opening of the outer can 4 and welded to join the opening of the outer can 4 so that the inside of the battery is sealed.
  • the lid plate 9 is provided with an electrolyte inlet 14, and when the battery is assembled, the electrolyte is injected into the battery from the electrolyte inlet 14, and then the electrolyte inlet 14 is sealed. Stopped.
  • the cover plate 9 is provided with an explosion-proof safety valve 15.
  • the outer can 4 and the lid plate 9 function as a positive electrode terminal by directly welding the positive electrode lead body 7 to the lid plate 9, and the negative electrode lead body 8 is welded to the lead plate 13.
  • the terminal 11 functions as a negative electrode terminal by conducting the negative electrode lead body 8 and the terminal 11 through the lead plate 13, but depending on the material of the outer can 4, the sign may be reversed. There is also.
  • FIG. 2 is a perspective view schematically showing the external appearance of the battery shown in FIGS. 1A and 1B.
  • FIG. 2 is shown for the purpose of showing that the battery is a square battery.
  • a battery is schematically shown, and only specific ones of the constituent members of the battery are illustrated.
  • the inner peripheral side portion of the wound body electrode group 6 is not cross-sectioned, and the cross-section hatching is omitted in the separator 3.
  • Example 2 Urethane acrylate as an oligomer: 15 parts by mass, dipentoxylated pentaerythritol diacrylate as a monomer: 15 parts by mass, 2,4,6-trimethylbenzoylbisphenylphosphine oxide as a photopolymerization initiator: 0.15 parts by mass, Except for using a separator-forming slurry prepared by uniformly mixing 10 parts by weight of boehmite as an inorganic fine particle B (average particle size 0.6 ⁇ m) and 59.85 parts by weight of toluene as a volatile substance. A separator was produced in the same manner as in Example 1. And the nonaqueous electrolyte secondary battery was produced like Example 1 except having used this separator.
  • Example 3 A slurry for forming a separator was prepared in the same manner as in Example 1 except that the inorganic fine particles B were changed to titania (average particle size 0.6 ⁇ m), and the same procedure as in Example 1 was performed except that this slurry was used. A separator was produced. And the nonaqueous electrolyte secondary battery was produced like Example 1 except having used this separator.
  • Example 4 A separator-forming slurry was prepared in the same manner as in Example 1 except that the inorganic fine particles B were changed to alumina (average particle size 0.4 ⁇ m), and the slurry was used in the same manner as in Example 1 except that this slurry was used. A separator was produced. And the nonaqueous electrolyte secondary battery was produced like Example 1 except having used this separator.
  • Example 5 The same slurry for forming a separator as that prepared in Example 1 was applied to the surface of a polytetrafluoroethylene substrate with a gap of 40 ⁇ m using a die coater, followed by UV irradiation at an illuminance of 60 mW / cm 2 at 10. Irradiated for 2 seconds, dried, and then peeled off from the substrate to obtain a separator having a thickness of 16 ⁇ m.
  • a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that this separator was used.
  • a PET nonwoven fabric having a thickness of 12 ⁇ m is passed through this slurry, and after applying the slurry by pulling up, it is passed through a gap having a predetermined interval, followed by irradiation with ultraviolet rays at an illuminance of 60 mW / cm 2 for 10 seconds, and then It dried and obtained the porous membrane whose thickness is 12 micrometers. Thereafter, an emulsion containing PE fine particles (average particle diameter of PE fine particles of 1.0 ⁇ m) is applied to one side of the porous film with a die coater so that the thickness after drying becomes 4 ⁇ m, and dried to form a shutdown layer. To obtain a separator. A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that this separator was used.
  • Example 7 Urethane acrylate as an oligomer: 15.7 parts by mass, isobornyl acrylate as a monomer (crosslinking agent): 10.4 parts by mass, 2,4,6-trimethylbenzoylbisphenylphosphine oxide as a photopolymerization initiator: 0 .78 parts by mass, Boehmite as an inorganic fine particle B (average particle size 0.6 ⁇ m): 23.5 parts by mass, and toluene as a volatile substance: 49.62 parts by mass for uniform mixing A separator was prepared in the same manner as in Example 1 except that this slurry was used. And the nonaqueous electrolyte secondary battery was produced like Example 1 except having used this separator.
  • Example 8 The same slurry for forming the separator as that prepared in Example 1 was applied on the negative electrode similarly prepared in Example 1 with a gap of 40 ⁇ m using a die coater. After the application, ultraviolet rays were irradiated at an illuminance of 60 mW / cm 2 for 10 seconds and further dried to obtain an electrode (negative electrode) having a separator formed on the negative electrode mixture layer.
  • the separator was formed on both sides of the negative electrode, and the thickness of the layer in which the negative electrode mixture layer and the separator were integrated was 70 ⁇ m on both sides of the negative electrode current collector.
  • the electrode (negative electrode) integrated with the separator and the positive electrode prepared in Example 1 are stacked without interposing another separator therebetween, and wound to form a wound electrode group. did. Thereafter, a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 1.
  • Example 9 The same slurry for forming a separator as that prepared in Example 1 was applied on the negative electrode similarly prepared in Example 1 with a gap of 3 ⁇ m using a die coater. After the application, ultraviolet rays were irradiated at an illuminance of 60 mW / cm 2 for 10 seconds and further dried to obtain an electrode (negative electrode) having a separator formed on the negative electrode mixture layer. The separator was formed on both sides of the negative electrode, and the thickness of the layer in which the negative electrode mixture layer and the separator were integrated was 5 ⁇ m on each side of the negative electrode current collector.
  • the electrode (negative electrode) integrated with the separator and the positive electrode prepared in Example 1 are stacked without interposing another separator therebetween, and wound to form a wound electrode group. did. Thereafter, a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 1.
  • Example 3 A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that a PE microporous membrane having a thickness of 16 ⁇ m was used as the separator.
  • This slurry was applied on the negative electrode prepared in Example 1 with a gap of 9 ⁇ m using a die coater. After the application, ultraviolet rays were irradiated at an illuminance of 60 mW / cm 2 for 10 seconds and further dried to obtain an electrode (negative electrode) having a separator formed on the negative electrode mixture layer.
  • the separator was formed on both sides of the negative electrode, and the thickness of the layer in which the negative electrode mixture layer and the separator were integrated was 16 ⁇ m on each side of the negative electrode current collector.
  • the electrode (negative electrode) integrated with the separator and the positive electrode prepared in Example 1 are stacked without interposing another separator therebetween, and wound to form a wound electrode group. did. Thereafter, a nonaqueous electrolyte secondary battery was produced in the same manner as in Example 1.
  • Table 1 shows the configurations of the separators used in the nonaqueous electrolyte secondary batteries of Examples 1 to 9 and Comparative Examples 1 to 4.
  • a / b value means the ratio a / b between the volume a of the resin A (volume excluding the void volume) and the volume b of the inorganic fine particle B (volume excluding the void volume). It means that “the total amount of resin A and inorganic fine particles B” means the volume a of resin A (volume excluding pore volume) and inorganic relative to the total volume (volume excluding pore volume) of the constituent components of the separator. It means the ratio of the total volume with the volume b (volume excluding pore volume) of the fine particles B.
  • each separator in Example 8 and 9, negative electrode integrated separator was held in a thermostat at 150 ° C. for 1 hour, and the dimensions (width and length) before holding were compared with the dimensions after holding. As a result, no dimensional change was observed, and it was confirmed that the separator was able to prevent a decrease in battery safety due to shrinkage at high temperatures.
  • Example 6 and Comparative Example 3 using the separator having the shutdown resin for the shutdown characteristics evaluation, after charging under the same conditions as those during the charge / discharge test, the batteries were put into a thermostatic bath and from 30 ° C. The temperature was raised to 150 ° C. at a rate of 1 ° C. per minute, and the temperature was changed by measuring the internal resistance of the battery. The temperature at which the resistance value increased to 5 times or more the value at 30 ° C. was taken as the shutdown temperature of the separator. Further, after the temperature of the battery reached 150 ° C., a temperature increase test was performed in which the temperature of the thermostatic bath was maintained at 150 ° C. for 2 hours. During the temperature increase test, the state of the battery was observed and the maximum temperature reached by the battery was measured. Further, the voltage of the battery after the temperature increase test was measured. The above results are shown in Table 3.
  • the electrolyte secondary battery did not cause a fine short circuit and had good charge / discharge characteristics.
  • the separators used in the batteries of Examples 1 to 9 are excellent in dimensional stability at high temperatures, as shown in Table 3, the nonaqueous electrolyte secondary battery of Example 6 is Since the voltage drop after the temperature increase test is small and the shutdown function can be effectively operated, the temperature increase during the temperature increase test is suppressed, and high reliability and safety are obtained.
  • a slight short circuit occurred during charging in the charge / discharge test are because the battery of Comparative Example 1 lacks the flexibility of the separator, and the battery of Comparative Example 2 lacks short-circuit resistance between the positive and negative electrodes due to the small amount of inorganic fine particles B in the separator. It is guessed.
  • the separator used in the batteries of Examples 1 to 7 and the separator integrated electrode used in the batteries of Examples 8 and 9 can be manufactured by only a simple process, the separator and the battery (electrochemical element) ) Productivity.

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  • Inorganic Chemistry (AREA)
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Abstract

L'invention concerne un séparateur d'élément électrochimique qui se caractérise en ce qu'il comprend une résine (A) formée par photopolymérisation et dotée d'une structure de pont, et des particules fines inorganiques électriquement isolantes (B), le rapport a/b entre le volume (a) de la résine (A) et le volume (b) des particules inorganiques (B), exception faite du volume poreux, étant compris entre 0,6 et 9. Le procédé de fabrication dudit séparateur d'élément électrochimique se caractérise en ce qu'il comprend une étape pour former des pores en vaporisant une substance volatile à partir d'une feuille pour former un séparateur d'élément électrochimique contenant la substance volatile, ou bien une étape pour former des pores en extrayant un matériau avec un solvant spécifique à partir d'une feuille afin de former un séparateur d'élément électrochimique contenant le matériau soluble dans le solvant.
PCT/JP2011/070050 2010-10-21 2011-09-02 Séparateur d'élément électrochimique, procédé pour le fabriquer, électrode pour élément électrochimique, élément électrochimique WO2012053286A1 (fr)

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JP2012539635A JPWO2012053286A1 (ja) 2010-10-21 2011-09-02 電気化学素子用セパレータとその製造方法、電気化学素子用電極および電気化学素子

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JP2015069783A (ja) * 2013-09-27 2015-04-13 株式会社日立ハイテクノロジーズ 蓄電デバイス製造装置並びに蓄電デバイスおよびその製造方法
WO2015057815A1 (fr) 2013-10-18 2015-04-23 Miltec UV International, LLC Revêtement séparateur pour batterie avec particules de céramique liées par un polymère
WO2017138116A1 (fr) * 2016-02-10 2017-08-17 株式会社日立製作所 Batterie au lithium-ion et procédé de fabrication associé
JP2017527093A (ja) * 2014-07-18 2017-09-14 ミルテック ユーヴィー インターナショナル，エルエルシーＭｉｌｔｅｃ Ｕｖ Ｉｎｔｅｒｎａｔｉｏｎａｌ， Ｌｌｃ セラミック粒子がｕｖまたはｅｂ硬化ポリマー結合されたリチウム二次電池セパレーター、その生産方法
JP2019087523A (ja) * 2017-11-08 2019-06-06 三星エスディアイ株式会社Samsung SDI Co., Ltd. 多孔質絶縁層形成用組成物、非水電解質二次電池用電極、非水電解質二次電池及び非水電解質二次電池用電極の製造方法
JP2020524886A (ja) * 2017-10-31 2020-08-20 エルジー・ケム・リミテッド 分離膜基材がない分離膜及びこれを含む電気化学素子
US11808693B2 (en) 2018-10-26 2023-11-07 Lg Energy Solution, Ltd. Apparatus for measuring peel strength of battery part using electromagnet and peel strength measurement method using the same

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* Cited by examiner, † Cited by third party
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002529891A (ja) * 1998-11-04 2002-09-10 ビーエーエスエフ アクチェンゲゼルシャフト 複合材料及び電気化学電池
JP2008041581A (ja) * 2006-08-10 2008-02-21 Hitachi Maxell Ltd 巻回体電極群、角形二次電池およびラミネート形二次電池
WO2009103537A1 (fr) * 2008-02-20 2009-08-27 Carl Freudenberg Kg Non-tissé comportant un matériau de réticulation
JP2010170770A (ja) * 2009-01-21 2010-08-05 Hitachi Maxell Ltd 非水電解質二次電池およびその製造方法

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06124610A (ja) * 1992-10-09 1994-05-06 Hitachi Cable Ltd 絶縁電線
WO2008029922A1 (fr) * 2006-09-07 2008-03-13 Hitachi Maxell, Ltd. Séparateur de batterie, son procédé de fabrication et batterie secondaire au lithium
DE102006045041A1 (de) * 2006-09-25 2008-03-27 Evonik Degussa Gmbh Strahlenhärtbare Formulierung, die zu flexiblen Beschichtungen mit erhöhtem Korrosionsschutz auf Metalluntergründen führt

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002529891A (ja) * 1998-11-04 2002-09-10 ビーエーエスエフ アクチェンゲゼルシャフト 複合材料及び電気化学電池
JP2008041581A (ja) * 2006-08-10 2008-02-21 Hitachi Maxell Ltd 巻回体電極群、角形二次電池およびラミネート形二次電池
WO2009103537A1 (fr) * 2008-02-20 2009-08-27 Carl Freudenberg Kg Non-tissé comportant un matériau de réticulation
JP2010170770A (ja) * 2009-01-21 2010-08-05 Hitachi Maxell Ltd 非水電解質二次電池およびその製造方法

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* Cited by examiner, † Cited by third party
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JP2015069783A (ja) * 2013-09-27 2015-04-13 株式会社日立ハイテクノロジーズ 蓄電デバイス製造装置並びに蓄電デバイスおよびその製造方法
EP3058607B1 (fr) * 2013-10-18 2022-04-13 Miltec UV International, LLC Revêtement séparateur pour batterie avec particules de céramique liées par un polymère
JP2016533631A (ja) * 2013-10-18 2016-10-27 ミルテック ユーヴィー インターナショナル，エルエルシーＭｉｌｔｅｃ Ｕｖ Ｉｎｔｅｒｎａｔｉｏｎａｌ， Ｌｌｃ ポリマー結合されたセラミック粒子電池セパレーターコーティング
WO2015057815A1 (fr) 2013-10-18 2015-04-23 Miltec UV International, LLC Revêtement séparateur pour batterie avec particules de céramique liées par un polymère
JP2021153054A (ja) * 2013-10-18 2021-09-30 ミルテック ユーヴィー インターナショナル, エルエルシーMiltec Uv International, Llc ポリマー結合されたセラミック粒子電池セパレーターコーティング
US10811651B2 (en) 2013-10-18 2020-10-20 Miltec UV International, LLC Polymer-bound ceramic particle battery separator coating
US10818900B2 (en) 2014-07-18 2020-10-27 Miltec UV International, LLC UV or EB cured polymer-bonded ceramic particle lithium secondary battery separators, method for the production thereof
JP2020191292A (ja) * 2014-07-18 2020-11-26 ミルテック ユーヴィー インターナショナル，エルエルシーＭｉｌｔｅｃ Ｕｖ Ｉｎｔｅｒｎａｔｉｏｎａｌ， Ｌｌｃ セラミック粒子がｕｖまたはｅｂ硬化ポリマー結合されたリチウム二次電池セパレーター、その生産方法
JP2017527093A (ja) * 2014-07-18 2017-09-14 ミルテック ユーヴィー インターナショナル，エルエルシーＭｉｌｔｅｃ Ｕｖ Ｉｎｔｅｒｎａｔｉｏｎａｌ， Ｌｌｃ セラミック粒子がｕｖまたはｅｂ硬化ポリマー結合されたリチウム二次電池セパレーター、その生産方法
JP6227168B1 (ja) * 2016-02-10 2017-11-08 株式会社日立製作所 リチウムイオン電池およびその製造方法
WO2017138116A1 (fr) * 2016-02-10 2017-08-17 株式会社日立製作所 Batterie au lithium-ion et procédé de fabrication associé
JP2020524886A (ja) * 2017-10-31 2020-08-20 エルジー・ケム・リミテッド 分離膜基材がない分離膜及びこれを含む電気化学素子
US11990641B2 (en) 2017-10-31 2024-05-21 Lg Energy Solution, Ltd. Separator having no separator substrate and electrochemical device including the same
JP2019087523A (ja) * 2017-11-08 2019-06-06 三星エスディアイ株式会社Samsung SDI Co., Ltd. 多孔質絶縁層形成用組成物、非水電解質二次電池用電極、非水電解質二次電池及び非水電解質二次電池用電極の製造方法
JP7221592B2 (ja) 2017-11-08 2023-02-14 三星エスディアイ株式会社 多孔質絶縁層形成用組成物、非水電解質二次電池用電極、非水電解質二次電池及び非水電解質二次電池用電極の製造方法
US11808693B2 (en) 2018-10-26 2023-11-07 Lg Energy Solution, Ltd. Apparatus for measuring peel strength of battery part using electromagnet and peel strength measurement method using the same

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