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WO2020050377A1 - Séparateur pour élément électrochimique et élément électrochimique l'utilisant - Google Patents

Séparateur pour élément électrochimique et élément électrochimique l'utilisant Download PDF

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Publication number
WO2020050377A1
WO2020050377A1 PCT/JP2019/035073 JP2019035073W WO2020050377A1 WO 2020050377 A1 WO2020050377 A1 WO 2020050377A1 JP 2019035073 W JP2019035073 W JP 2019035073W WO 2020050377 A1 WO2020050377 A1 WO 2020050377A1
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Prior art keywords
separator
porous layer
microporous substrate
electrochemical device
electrochemical
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English (en)
Japanese (ja)
Inventor
晋大 福田
昇三 増田
純二 道添
上岡　武則
陽平 鈴木
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Toray Industries Inc
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Toray Industries Inc
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Priority to JP2019569974A priority Critical patent/JPWO2020050377A1/ja
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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
    • H01M50/463—Separators, membranes or diaphragms characterised by their shape
    • 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
    • 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
    • H01M50/443—Particulate 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
    • H01M50/489—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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/52—Separators
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a separator for an electrochemical device having a porous layer on a microporous substrate, and an electrochemical device having the separator.
  • Lithium-ion secondary batteries have been capable of high performance and long-term operation of electronic devices such as mobile phones and notebook computers as rechargeable high-capacity batteries. Recently, lithium ion secondary batteries have been mounted as driving batteries for environmentally friendly vehicles such as electric vehicles and hybrid electric vehicles, and are expected to further ensure safety and improve the performance of batteries.
  • environmentally friendly vehicles such as electric vehicles and hybrid electric vehicles
  • various types of batteries that make up the battery to improve various battery characteristics such as higher battery capacity, input / output characteristics, life characteristics, temperature characteristics, storage characteristics, etc.
  • Many considerations have been given to materials. As one of them, various studies have been made on a separator disposed between a positive electrode and a negative electrode, and various improvements have been made on the surface condition of the separator. For example, Patent Documents 1 to 4 disclose forming a linear groove on the surface of a separator.
  • the separator since the separator has a porous structure, there is no stiffness, and wrinkles are likely to be generated on the porous composite film during transportation and winding. In addition, wrinkles are also likely to occur when the battery is manufactured in the course of manufacturing. If the wrinkles are large, it may cause defects in appearance, cause reaction unevenness and cause lithium deposition, not only may impair the safety of the battery, but also may not make uniform contact with the electrodes, resulting in poor adhesion. Tends to worsen. If the adhesion between the separator and the electrode is low, when the lithium secondary battery is used repeatedly, voids are generated between the electrode and the separator, and lithium metal precipitates at that portion, thereby resulting in the life of the secondary battery.
  • the problem to be solved by the present invention is to prevent the deterioration of transportability that occurs in the separator transporting process during the manufacturing process of a separator or a battery, and to mainly prevent the generation of wrinkles, and furthermore, its safety and repeated use characteristics ( It is an object of the present invention to provide a separator for an electrochemical element having a porous layer in which the adhesiveness to an electrode is further improved in order to increase the lifetime, and an electrochemical element having the separator.
  • the present inventors have provided a microporous substrate and a porous layer formed on one or both surfaces of the microporous substrate and containing a mixture of inorganic particles and a binder polymer.
  • the cross-sectional shape of the surface of the porous layer measured by a white interference microscope with respect to the cross-sectional shape of the surface of the porous layer is adjusted to satisfy a specific value, so that the surface of the porous layer has a specific continuous linear shape. It has been found that an uneven structure can be obtained. That is, the present invention employs the following configuration in order to solve the above-mentioned problems.
  • An electrochemical device separator comprising: a microporous substrate; and a porous layer formed on one or both surfaces of the microporous substrate and containing a mixture of inorganic particles and a binder polymer.
  • the binder polymer is polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-trichloroethylene, polymethyl methacrylate, polybutyl acrylate, polyacrylonitrile, polyvinyl pyrrolidone, polyvinyl acetate, polyvinyl alcohol, ethylene vinyl acetate copolymer, poly Selected from the group consisting of ethylene oxide, polyarylate, styrene-butadiene rubber, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, and carboxymethyl cellulose.
  • Separator for gas-chemical element [4] The separator for an electrochemical element according to any one of [1] to [3], wherein the inorganic particles are at least one selected from the group consisting of titanium dioxide, alumina, and boehmite.
  • An electrochemical device separator includes an electrode assembly including a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, and a battery case that accommodates the electrode assembly. It is suitable as a separator. Further, since the electrochemical element separator of the present invention has a specific continuous linear uneven structure on the surface of the porous layer, the electrochemical element separator manufacturing process and the electrochemical element during the battery manufacturing process In the separator transporting process, the characteristic of suppressing the generation of wrinkles due to air biting or the like is improved. Furthermore, in addition to the improvement of the characteristic of suppressing the generation of wrinkles, the adhesiveness to the electrode in the battery is improved.
  • FIG. 4 is a schematic diagram of an apparatus related to transport stability evaluation in each embodiment.
  • FIG. 3 is a front sectional view schematically illustrating a wet bending strength test.
  • the separator for an electrochemical element is a microporous substrate, formed on one surface or both surfaces of the microporous substrate, a porous material containing a mixture of inorganic particles and a binder polymer.
  • S 1 the number of points included in the range of 0.8T 1 ⁇ T 1, 0 ⁇ S 1 ⁇ 0.4P 1
  • S 2 the number of points included in the range of 0.8T 2 ⁇ T 2, 0 ⁇ S 2 ⁇ 0.4P 2 .
  • the electrochemical element separator according to the embodiment of the present invention, a microporous substrate, Formed on one or both surfaces of the microporous substrate, comprising a porous layer containing a mixture of inorganic particles and a binder polymer, A separator for an electrochemical element, Continuous linear grooves are formed at intervals on the surface of the porous layer, The pitch of the linear grooves is 0.2 to 10 mm, and The depth of the linear groove may be 25 to 80% of the thickness of the porous layer.
  • microporous substrate any material can be used as long as it can be used as a microporous substrate of an electrochemical element.
  • polyolefin, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyamide, polycarbonate, polyimide, Microporous substrates formed of polyetheretherketone, polyethersulfone, polyphenyleneoxide, polyphenylenesulfide, polyethylenenaphthalene, and the like can be given.
  • a polyolefin-based microporous substrate from the viewpoint of heat resistance and cost, and it is further preferable to use a microporous substrate formed of polyethylene, polypropylene, polybutylene, and polypentene. preferable.
  • the form of the microporous substrate any of a film form and a nonwoven form can be used.
  • the thickness of the microporous substrate is not particularly limited, but is preferably 5 to 50 ⁇ m, and the size of the pores present in the microporous substrate is preferably 0.01 to 50 ⁇ m. Is preferably 10 to 95%.
  • the pore size is a through-hole diameter measured according to a bubble point method (half dry method) described in JIS K3832.
  • the porosity here is such that the constituent materials are composed of a, b,..., N, the masses of the constituent materials are Wa, Wb,, and Wn (g ⁇ cm 2 ).
  • the film thickness of interest is t (cm)
  • the film thickness of the layer of interest is porosity ⁇ , t (cm)
  • the following equation is used. This is the value ( ⁇ (%)) determined in (1a).
  • ⁇ ⁇ 1- (Wa / da + Wb / db +... + Wn / dn) / t ⁇ ⁇ 100 (1a)
  • a porous layer is formed on one or both surfaces of the microporous substrate.
  • the porous layer contains a mixture of inorganic particles and a binder polymer.
  • a polyolefin-based microporous substrate is preferably used as the microporous substrate constituting the separator for an electrochemical device according to the embodiment of the present invention (hereinafter, may be simply referred to as “separator”).
  • the polyolefin-based microporous substrate exhibits a severe heat shrinkage behavior at a temperature of 100 ° C. or more, depending on the material properties and the properties in the manufacturing process including stretching.
  • a porous layer containing a mixture of inorganic particles and a binder polymer is provided on at least one surface of the microporous substrate constituting the separator.
  • the binder polymer adheres the inorganic particles to each other (that is, the binder polymer connects and fixes the inorganic particles) so that the inorganic particles can maintain a state of being bound to each other.
  • the inorganic particles of the porous layer exist as a structure filled in a state where they are substantially in contact with each other, and empty spaces formed in a state where the inorganic particles are in contact form pores of the porous layer.
  • the separator having such a porous layer is interposed between the electrodes to form an electrochemical device.
  • the binder polymer in the porous layer maintains a state of being bound to the microporous base material, and is interposed between the electrodes as a separator, and maintains a state of being bound to the electrode. Even if such a separator has a porous layer formed, wrinkles are likely to be generated when air is caught in a separator transporting step in manufacturing a separator or a battery in a state where the surface shape is flat. On the other hand, even if it has a linear concavo-convex structure to allow air to escape, the point of contact with a roll or the like is not a point, but a surface structure having a surface has high friction and the effect of improving transportability is low. .
  • the provision of the linear groove improves the adhesiveness to the electrode required at the time of manufacturing the battery.
  • pouch-type batteries are particularly difficult to apply pressure compared to square and cylindrical batteries, which can be pressurized in the battery case (outer body).
  • partial separation easily occurs at the interface between the separator and the electrode.
  • the battery swells, the resistance inside the battery increases, and the cycle performance decreases.
  • the pouch type lithium secondary battery cannot be replaced because it is integrated with the electronic device. Therefore, the separator is particularly required to have adhesiveness to the electrode in the battery after the electrolyte is injected.
  • the adhesive strength is defined by a wet bending strength obtained by a measurement method described later as an index.
  • the wet flexural strength is preferably 0.20 to 1.0 N / mm, more preferably 0.25 to 0.7 N / mm. If it is less than 0.20 N / mm, the adhesiveness is not sufficient and the cycle is likely to be reduced. If it exceeds 1.0 N / mm, the adhesiveness at room temperature will inevitably increase, and the handleability will decrease. Similar to the above-described suppression of wrinkle generation, Patent Documents 1 to 4 describe that a linear groove is provided on the surface of a separator.
  • the cross-sectional shape of the surface of the porous layer containing the mixture of the inorganic particles and the binder polymer was measured by a white interference microscope in the width direction.
  • the maximum value of the thickness of the porous layer in the direction (Y-axis) from the side of the microporous substrate toward the side of the surface of the porous layer at a field width of 2.2 mm is defined as T 1 and the minimum value.
  • the number of points having a value equal to or greater than T 0 is P 1
  • the number of points having a value smaller than T 0 is P 2 0.8 ⁇ P 1 / P 2 ⁇ 1.2
  • the S 1 the number of points included in the range of 0.8T 1 ⁇ T 1, 0 ⁇ S 1 ⁇ 0.4P 1
  • the S 2 the number of points included in the range of 0.8T 2 ⁇ T 2, 0 ⁇ S 2 ⁇ 0.4P 2
  • T 1 , T 2 0 , P 1 , and P 2 satisfy the specific numerical ranges as described above, the surface of the porous layer can have a specific continuous linear uneven structure.
  • 1 and 2 show a separator according to a preferred embodiment of the present invention.
  • the embodiments described in the present specification and the configurations shown in the drawings are merely preferred embodiments of the present invention, and the present invention is not limited thereto.
  • the continuous linear concavo-convex structure may be a continuous linear concave groove.
  • the separator 100 for an electrochemical element according to the embodiment of the present invention has one of the surfaces of the microporous substrate 10 in order to improve the separator manufacturing process and the effect of suppressing wrinkles during battery life. It is preferable to have a porous layer 20 in which continuous linear grooves 30 for improving the effect of suppressing the generation of wrinkles are formed on the surface or both surfaces at intervals.
  • Such a continuous linear groove 30 is not particularly limited in its shape, except that it satisfies the numerical range defined as described above, but is connected from one cut surface of the separator to the other cut surface.
  • the structure may be a continuous uneven structure that is continuous but periodic. Further, the cross section of such a groove may be a triangle, a semicircle, or the like, but this may be a cross section of various forms simply by a manufacturing method, and is not particularly limited to that form.
  • the depth (h) of the groove of the separator is preferably 0.1 ⁇ m or more and less than 80% of the thickness of the porous layer. More preferably, it is 0.1 ⁇ m or more and less than 25% of the thickness of the porous layer.
  • the depth (h) of the groove of the separator is 0.1 ⁇ m or more and less than 80% of the thickness of the porous layer, wrinkles are less likely to occur during transportation, and the adhesion to the electrode during battery production is improved.
  • the depth (h) of the groove of the separator is 0.1 ⁇ m or more and less than 25% of the thickness of the porous layer, the cleaning liquid at the time of coating and cleaning is less likely to remain in the groove, and the drying process is suitable.
  • the water content of the separator after drying is low, a high-life, high-life battery with good cycle characteristics when a battery is manufactured can be provided.
  • the depth (h) of the groove of the separator is 80% or more of the thickness of the porous layer, the cleaning liquid at the time of coating and cleaning tends to remain in the groove, which deteriorates the drying process aptitude and the binder. Since the amount of decrease in the area where the polymer contacts the electrode is too large, the adhesiveness to the electrode is reduced.
  • the maximum value of the Y-axis is defined as T 1
  • the minimum value is defined as T 1
  • T 2 is expressed by T 1 -T 2 when the value is T 2 .
  • the pitch (w) of the concave groove according to the embodiment of the present invention is preferably 0.2 to 20 mm. When the pitch (w) of the concave grooves is within this range, an effect of suppressing wrinkles can be obtained. If the pitch of the grooves is less than 0.2 mm, the pitch of the grooves is too narrow and out of the measurement range. If the pitch of the grooves exceeds 20 mm, the pitch of the grooves may be too wide, and the effect of suppressing wrinkles may be reduced.
  • the pitch (w) of the groove of the separator is determined from the bottom of the valley in the cross-sectional profile of the processed image by performing imaging and image processing of the cross section of the separator by the method described in the example.
  • the horizontal distance to the bottom of the adjacent valley is defined as the pitch
  • the average value of the pitch obtained by the repetitive method is defined as the pitch of the groove.
  • Binder polymer Although the kind of the binder polymer is not particularly limited, it is preferable that the binder polymer contains a fluorine-based resin from the viewpoint of adhesion to an electrode and electrochemical stability.
  • fluororesin As the fluororesin, from the viewpoint of heat resistance and electrode adhesion, vinylidene fluoride homopolymer, vinylidene fluoride-fluorinated olefin copolymer, vinyl fluoride homopolymer and vinyl fluoride-fluorinated olefin copolymer are used. It is preferable to use one or more selected from the group consisting of coalescence. In particular, a vinylidene fluoride-hexafluoropropylene copolymer and a polymer containing a vinylidene fluoride unit are preferable.
  • the vinylidene fluoride-hexafluoropropylene copolymer preferably contains a hydrophilic group, and preferably contains 0.3 to 3 mol% of hexafluoropropylene.
  • the copolymer has high affinity for the electrolyte, high chemical and physical stability, exhibits bending strength when wet, and maintains sufficient affinity with the electrolyte even when used at high temperatures it can. Since the vinylidene fluoride-hexafluoropropylene copolymer (A) has a hydrophilic group, it can be strongly bonded to an active material present on the electrode surface and a binder component in the electrode.
  • hydrophilic group examples include a hydroxyl group, a carboxylic acid group, a sulfonic acid group, and salts thereof.
  • the introduction of a hydrophilic group into vinylidene fluoride can be achieved by, for example, adding a hydrophilic group such as maleic anhydride, maleic acid, maleic ester, or monomethyl maleate in the synthesis of vinylidene fluoride-hexafluoropropylene copolymer (A).
  • the lower limit of the content of the vinylidene fluoride-hexafluoropropylene copolymer is preferably 15% by mass or more based on the total mass of the vinylidene fluoride-hexafluoropropylene copolymer and the polymer containing the vinylidene fluoride unit. , More preferably at least 25% by mass, and the upper limit is preferably at most 85% by mass, more preferably at most 75% by mass.
  • the lower limit of the weight average molecular weight of the vinylidene fluoride-hexafluoropropylene copolymer is larger than 750,000, preferably 900,000 or more, and the upper limit is preferably 2,000,000 or less, more preferably 1.5 million or less.
  • the polymer containing a vinylidene fluoride unit is preferably a resin made of polyvinylidene fluoride or a copolymer having a vinylidene fluoride unit.
  • the monomer other than the vinylidene fluoride unit include tetrafluoroethylene, trifluoroethylene, trichloroethylene, hexafluoropropylene, vinyl maleic anhydride, maleic acid, maleic ester, and monomethyl maleate. And one or more of these.
  • the lower limit of the weight average molecular weight of the polymer containing vinylidene fluoride units is preferably 100,000 or more, more preferably 150,000 or more, and the upper limit is preferably 750,000 or less, more preferably 700,000 or less.
  • the binder polymer may include an acrylic resin.
  • an acrylic resin a (meth) acrylate polymer or a copolymer thereof is preferable.
  • the (meth) acrylate means an acrylate (acrylate) and a methacrylate (methacrylate).
  • Examples of the (meth) acrylate include methyl acrylate, ethyl acrylate, n-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, t-butyl methacrylate, and 2-ethylhexyl methacrylate. And the like.
  • the lower limit of the content of the acrylic resin is preferably at least 4% by mass, more preferably 5% by mass, based on the total mass of the vinylidene fluoride-hexafluoropropylene copolymer, the polymer containing vinylidene fluoride units, and the acrylic resin.
  • the upper limit is preferably 40% by mass or less, more preferably 30% by mass or less, and even more preferably 20% by mass or less.
  • the binder polymer the following resins including the above-mentioned fluorine resin and acrylic resin can be preferably used.
  • the binder polymer is polyvinylidene fluoride-hexafluoropropylene, polyvinylidene fluoride-trichloroethylene, polymethyl methacrylate, polybutyl acrylate, polyacrylonitrile, polyvinyl pyrrolidone, polyvinyl acetate, polyvinyl alcohol, ethylene vinyl acetate copolymer, polyethylene oxide , Polyarylate, styrene-butadiene rubber, cellulose acetate, cellulose acetate butyrate, cellulose acetate propionate, cyanoethyl pullulan, cyanoethyl polyvinyl alcohol, cyanoethyl cellulose, cyanoethyl sucrose, pullulan, and any selected from the group consisting of carboxymethyl cellulose It is preferable to include one or two or more kinds.
  • the content of the binder polymer is preferably 1 to 55% by mass with respect to the inorganic particles.
  • the content of the binder polymer is 1% by mass or more, the inorganic particles can be sufficiently bound to each other, and when the content is 55% by mass or less, the microporosity of the porous layer is improved and the wettability to the electrolytic solution is improved. improves.
  • the inorganic particles are not particularly limited as long as they are electrochemically stable. That is, the inorganic particles that can be used in the embodiment of the present invention are those that do not cause an oxidation and / or reduction reaction in the operating voltage range (for example, 0 to 5 V based on Li / Li + ) of the electrochemical device used.
  • the operating voltage range for example, 0 to 5 V based on Li / Li +
  • calcium phosphate, amorphous silica, crystalline glass filler, kaolin, talc, titanium dioxide, alumina, silica-alumina composite oxide particles, barium sulfate, calcium fluoride, lithium fluoride, zeolite, sulfide Molybdenum, mica, boehmite and the like can be mentioned.
  • the inorganic particles may be a true sphere, a substantially sphere, or a plate, but is not particularly limited.
  • the lower limit of the content of the inorganic particles is preferably 30% by volume or more, more preferably 45% by volume or more, based on the total of the binder polymer and the inorganic particles. It is preferably at least 50% by volume, and the upper limit is preferably at most 75% by volume, more preferably at most 70% by volume.
  • the content of the inorganic particles is in this range, a favorable balance can be obtained without appropriately lowering the frictional force between the separator and the transport rolls described above without deteriorating the function of the separator.
  • the average particle size of the inorganic particles is preferably 1.5 times or more and 50 times or less the size of the pores of the microporous substrate. More preferably, it is 2.0 times or more and 20 times or less.
  • the average particle size of the inorganic particles is within the above preferred range, the air permeability resistance is maintained without closing the pores of the separator in a state where the binder polymer and the inorganic particles are mixed, and the particles are further included in the battery assembly process. To prevent the battery from falling off and causing serious battery failure.
  • the average particle size of the inorganic particles is a value measured according to ISO13320.
  • the porous layer may contain crosslinked polymer particles in addition to the inorganic particles.
  • the upper limit of the content of the inorganic particles contained in the porous layer is preferably 80% by volume or less, more preferably 70% by volume or less, and the lower limit is 25% by volume or more based on the total mass of the porous layer. Is more preferably 45% by volume or more, and still more preferably 46% by volume or more.
  • the thickness of the porous layer is preferably 0.5 to 3 ⁇ m per side, more preferably 1 to 2.5 ⁇ m, and further preferably 1 to 2 ⁇ m. If the film thickness per side is 0.5 ⁇ m or more, the functions (for example, heat resistance, adhesiveness, etc.) required for the porous layer can be ensured even if the linear groove is provided. When the film thickness per side is 3 ⁇ m or less, the volume of winding can be suppressed, which is suitable for increasing the capacity of a battery which will proceed in the future.
  • the porosity of the porous layer is preferably 30 to 90%, more preferably 40 to 70%. By setting the porosity of the porous layer within the above preferred range, an increase in the electrical resistance of the separator can be prevented, a large current can be passed, and the film strength can be maintained.
  • the coating liquid and the application of the coating liquid are subjected to a pattern layer formation coefficient U (1 / m) by a groove shown below of 500,000.
  • the separator can be manufactured by a conventional wet coating method in the same manner as in the method of manufacturing the separator, except that the separation is performed within the range of ⁇ 2,000,000, preferably in the range of 000600,000 ⁇ 11,000,000.
  • U ⁇ ⁇ V / ( ⁇ ⁇ D) (2)
  • the mechanism is not clear, but in the range where U is applied, the part where the coating liquid applied to the substrate separates (die tip, gravure roll, scraper, knife, etc., exists regardless of the coating method)
  • the coating liquid tends to form a fine spherical structure on the substrate in order to maintain a stable shape by increasing the curvature of the meniscus formed in step (i). It is considered that a speed difference occurs between the center and the end of the sphere, and a difference occurs in the speed at which the coating liquid follows the base material, thereby forming an initial groove shape. It is considered that similar structure formation is spread in the width direction of the base material in order to maintain the balance of the influence of the speed difference, thereby forming groove shapes arranged in the width direction shown below.
  • ⁇ indicates the viscosity (mPa ⁇ s) of the coating liquid.
  • the viscosity ⁇ of the coating liquid can be adjusted by the solid content of the coating liquid, the supply temperature (preferably in the range of 10 to 50 ° C.), and the addition of a thickener.
  • the viscosity ⁇ of the coating liquid is preferably from 200 to 2000 mPa ⁇ s, more preferably from 500 to 1000 mPa ⁇ s.
  • the viscosity ⁇ is 200 mPa ⁇ s or more, the wet spread of the coating liquid on the surface of the microporous base material is small, the desired thickness of the porous layer is obtained, and the depth of the linear groove is obtained.
  • the viscosity ⁇ is 2000 mPa ⁇ s or less, the viscosity is low, and a desired thickness of the porous layer can be obtained by a wet coating method, and a pitch of the linear groove can be obtained.
  • the viscosity is a value measured using a viscometer (DVI-PRIME manufactured by BROOKFIELD) at 25 ° C. as described in Examples.
  • the water content of the separator is preferably 500 ppm or less, more preferably 300 ppm or less.
  • the water content of the separator is 500 ppm or less, deterioration of the battery can be prevented when the battery is manufactured.
  • the water content exceeds 500 ppm there is a possibility that when a battery is manufactured, it greatly contributes to deterioration of the battery. Therefore, a film from which moisture is removed as much as possible is suitable for a film used for a separator of a lithium ion battery.
  • the moisture content is measured by using a moisture vaporizer (“ADP-611” manufactured by Kyoto Electronics Industry Co., Ltd.) in an environment of 23 ° C. and 65% RH as described in Examples. Value.
  • ⁇ indicates the surface tension (mN / m) of the coating liquid.
  • the surface tension ⁇ can be adjusted by adding an additive such as an emulsifier.
  • the surface tension ⁇ is preferably such that the surface tension is as low as possible in order to ensure wettability with the microporous substrate, specifically, 20 to 50 mN / m, more preferably 25 to 45 mN / m. m.
  • the surface tension ⁇ is 20 mN / m or more, the spread of wetness is small, and the penetration into the microporous base material is reduced, so that a desired thickness of the porous layer can be obtained and the depth of the linear groove can be reduced.
  • the surface tension ⁇ is 50 mN / m or less, it is possible to coat the porous substrate.
  • the surface tension ⁇ is a value measured by the hanging drop method at 25 ° C. as described in Examples.
  • V indicates the transport speed (m / s) of the substrate.
  • the transport speed V can be adjusted by mechanical control in the process, for example, the speed or tension of a roller.
  • the transport speed V is preferably from 0.5 to 3.3 m / s, more preferably from 0.7 to 2.0 m / s.
  • the transport speed V is 0.5 m / s or more, the surface of the coating liquid does not level, and a groove can be formed.
  • the transport speed V is 3.3 m / s or less, wet coating transport becomes possible.
  • D 2d1
  • d1 represents a coating film thickness ( ⁇ m) per one surface of the application surface.
  • the coating thickness d1 can be adjusted by the viscosity of the coating liquid, the surface tension, the coating amount, and the coating area.
  • the coating film thickness d1 is preferably from 2.5 ⁇ m to 50 ⁇ m, more preferably from 7.5 ⁇ m to 25 ⁇ m. When the coating thickness d1 is 2.5 ⁇ m or more, the function of the porous film is exhibited. When the coating film thickness d1 is 50 ⁇ m or less, a function as a separator of the electrochemical element is exhibited.
  • the coating film thickness d1 is a value calculated by dividing the film thickness of the porous layer by the solid content volume% as described in Examples.
  • Preparation of Coating Liquid includes the following steps (a) and (b) sequentially.
  • steps (a) and (b) sequentially.
  • a vinylidene fluoride-hexafluoropropylene copolymer which is a fluorine-based resin and a polymer containing a vinylidene fluoride unit as a binder resin, and an acrylic resin is used as necessary is described. It is.
  • A a step of obtaining a fluororesin solution in which a vinylidene fluoride-hexafluoropropylene copolymer and a polymer containing vinylidene fluoride units are dissolved in a solvent;
  • B a step of adding an acrylic resin solution as necessary to the fluororesin solution and mixing to obtain a coating solution;
  • the solvent can dissolve a vinylidene fluoride-hexafluoropropylene copolymer and a polymer containing a vinylidene fluoride unit.
  • the acrylic resin is further dissolved or dispersed. It is not particularly limited as long as it can be mixed with the coagulating liquid. From the viewpoint of solubility and low volatility, the solvent is preferably N-methyl-2-pyrrolidone.
  • a vinylidene fluoride-hexafluoropropylene copolymer and a polymer containing vinylidene fluoride units are dissolved in a solvent, and particles (inorganic particles and, if necessary, crosslinked polymer particles, etc.) are added thereto with stirring, and a certain amount is added.
  • particles inorganic particles and, if necessary, crosslinked polymer particles, etc.
  • the fluororesin solution in which the aggregation of the particles is reduced is obtained. obtain.
  • (B) Step of Obtaining a Coating Liquid A vinylidene fluoride-hexafluoropropylene copolymer, a polymer containing vinylidene fluoride units, and an acrylic resin solution are added as necessary to a fluororesin solution containing particles. Then, a coating liquid is prepared by mixing with a three-one motor equipped with stirring blades. In the preparation of the coating liquid, the viscosity ⁇ and the surface tension ⁇ of the coating liquid are adjusted so that the pattern layer formation coefficient U falls within the above range.
  • the acrylic resin solution is a solution in which the acrylic resin is dissolved or dispersed in a solvent, and the solvent used here is preferably the same solvent as in step (a).
  • N-methyl-2-pyrrolidone is preferred from the viewpoint of solubility and low volatility. It is preferable from the viewpoint of operability that the acrylic resin solution is obtained by polymerizing the acrylic resin, adding N-methyl-2-pyrrolidone and distilling the solvent to replace the solvent.
  • microporous substrate for example, a polyolefin-based microporous substrate is not particularly limited as long as a polyolefin-based microporous substrate having desired properties can be produced.
  • a polyolefin-based microporous substrate having desired properties can be produced.
  • the methods described in the specifications of Japanese Patent No. 2132327 and Japanese Patent No. 3347835, International Publication WO2006 / 137540 and the like can be used. Specifically, it is preferable to include the following steps (i) to (v).
  • Step of preparing polyolefin solution An appropriate film-forming solvent is added to the polyolefin resin, and the mixture is melt-kneaded to prepare a polyolefin solution.
  • a method using a twin-screw extruder described in the specifications of Japanese Patent No. 2132327 and Japanese Patent No. 3347835 can be used.
  • the melt-kneading method is well-known, and thus the description is omitted.
  • the mixing ratio of the polyolefin resin and the solvent for film formation in the polyolefin solution is not particularly limited, but is preferably 70 to 80 parts by mass of the solvent for film formation with respect to 20 to 30 parts by mass of the polyolefin resin.
  • proportion of the polyolefin resin is within the above range, swell and neck-in can be prevented at the die exit when the polyolefin solution is extruded, so that the extruded body (gel-shaped body) has good moldability and self-supporting property.
  • the polyolefin solution is fed from an extruder to a die and extruded into a sheet.
  • a plurality of polyolefin solutions of the same or different compositions may be fed from an extruder to one die, where they may be laminated in layers and extruded into sheets.
  • the extrusion method may be either a flat die method or an inflation method.
  • the extrusion temperature is preferably 140 to 250 ° C., and the extrusion speed is preferably 0.2 to 15 m / min.
  • the film thickness can be adjusted by adjusting each extrusion amount of the polyolefin solution.
  • the extrusion method for example, the methods disclosed in Japanese Patent No. 2132327 and Japanese Patent No. 3347835 can be used.
  • the obtained extruded product is cooled to form a gel-like sheet.
  • a method for forming the gel-like sheet for example, the methods disclosed in Japanese Patent No. 2132327 and Japanese Patent No. 3347835 can be used. Cooling is preferably performed at a rate of at least 50 ° C./min up to the gelation temperature. Cooling is preferably performed to 25 ° C. or lower. By cooling, the microphase of the polyolefin separated by the film-forming solvent can be fixed. When the cooling rate is within the above range, the crystallinity is kept in an appropriate range, and a gel-like sheet suitable for stretching is obtained.
  • a method of contacting with a cooling medium such as cold air or cooling water, a method of contacting with a cooling roll, or the like can be used.
  • the obtained gel-like sheet is stretched in at least a uniaxial direction. Since the gel-like sheet contains a solvent for film formation, it can be stretched uniformly. After heating, the gel-like sheet is preferably stretched at a predetermined magnification by a tenter method, a roll method, an inflation method, or a combination thereof.
  • the stretching may be uniaxial stretching or biaxial stretching, but biaxial stretching is preferred. In the case of biaxial stretching, any of simultaneous biaxial stretching, sequential stretching, and multi-stage stretching (for example, a combination of simultaneous biaxial stretching and sequential stretching) may be used.
  • the stretching ratio (area stretching ratio) in this step is preferably 9 times or more, more preferably 16 times or more, and particularly preferably 25 times or more.
  • the stretching ratios in the machine direction (MD) and the width direction (TD) may be the same or different from each other.
  • the stretching ratio in this step refers to the area stretching ratio of the microporous substrate immediately before being subjected to the next step, based on the microporous substrate immediately before this step.
  • the stretching temperature in this step is preferably in the range of the crystal dispersion temperature (Tcd) of the polyolefin resin to Tcd + 30 ° C., and in the range of the crystal dispersion temperature (Tcd) + 5 ° C. to the crystal dispersion temperature (Tcd) + 28 ° C. Is more preferable, and the temperature is particularly preferably in the range of Tcd + 10 ° C. to Tcd + 26 ° C.
  • the stretching temperature is preferably from 90 to 140 ° C, more preferably from 100 to 130 ° C.
  • the crystal dispersion temperature (Tcd) is determined by measuring the temperature characteristics of dynamic viscoelasticity according to ASTM D4065.
  • the stretching Due to the stretching as described above, cleavage occurs between the polyethylene lamellas, and the polyethylene phase becomes finer, and many fibrils are formed. Fibrils form a three-dimensionally irregularly connected network. Stretching increases the mechanical strength and enlarges the pores. However, if the stretching is performed under appropriate conditions, it is possible to control the diameter of the through-hole and to have a high porosity even with a thinner film thickness. Depending on the desired physical properties, the film may be stretched by providing a temperature distribution in the film thickness direction, whereby a microporous substrate having excellent mechanical strength is obtained. Details of the method are described in Japanese Patent No. 3347854.
  • the microporous substrate from which the solvent for film formation has been removed is dried by a heat drying method or an air drying method.
  • the drying temperature is preferably equal to or lower than the crystal dispersion temperature (Tcd) of the polyolefin resin, and particularly preferably lower than Tcd by 5 ° C. or more.
  • the drying is preferably performed until the residual washing solvent becomes 5% by mass or less, more preferably 3% by mass or less, with the microporous substrate being 100% by mass (dry mass).
  • the remaining washing solvent is within the above range, the porosity of the microporous substrate is maintained when the subsequent microporous substrate stretching step and heat treatment step are performed, and deterioration in permeability is suppressed. .
  • the formation of the porous layer includes (c) a step of applying a coating solution to a microporous substrate, immersing the coating solution in a coagulation solution, washing and drying.
  • (C) A step of applying a coating liquid to a microporous substrate, immersing in a coagulation liquid, washing and drying The coating liquid is applied to the microporous substrate, and the microporous coated with the coating liquid is applied.
  • the base material is immersed in a coagulation liquid to phase-separate a vinylidene fluoride-hexafluoropropylene copolymer and a polymer containing vinylidene fluoride units and, if necessary, an acrylic resin and a solvent, and coagulate in a state having a three-dimensional network structure. And wash and dry.
  • the transport speed V of the base material and the coating film thickness d1 are set so that the pattern layer formation coefficient U falls within the above-described range.
  • the method of applying the coating liquid to the microporous substrate may be a known method, for example, dip coating, reverse roll coating, gravure coating, kiss coating, roll brushing, spray coating. Methods, an air knife coating method, a Meyer bar coating method, a pipe doctor method, a blade coating method, a die coating method, and the like. These methods can be used alone or in combination.
  • the coating resistance coefficient M (kg / s) is preferably in the range of 10 to 60. More preferably, it is in the range of 20 to 40.
  • E is a resistance at the time of application, and is calculated from a tension difference between the applied portion and the applied portion.
  • V is the transport speed (m / s) of the substrate.
  • the coagulation liquid is preferably water, preferably an aqueous solution containing a vinylidene fluoride-hexafluoropropylene copolymer and a polymer containing vinylidene fluoride units and, if necessary, 1 to 20% by mass of a good solvent for an acrylic resin. It is preferably an aqueous solution containing 5 to 15% by mass. Examples of good solvents include N-methyl-2-pyrrolidone, N, N-dimethylformamide, and N, N-dimethylacetamide.
  • the immersion time in the coagulation liquid is preferably 3 seconds or more. There is no upper limit, but 10 seconds is sufficient. Water can be used for washing. Drying can be performed using hot air of 100 ° C. or less, for example.
  • the separator according to the embodiment of the present invention thus manufactured can be used as a separator of an electrochemical device. That is, the separator according to the embodiment of the present invention can be suitably used as a separator interposed between the positive electrode and the negative electrode.
  • Electrochemical elements include any element that performs an electrochemical reaction, and specific examples thereof include any kind of primary battery, secondary battery, fuel cell, solar cell, or a capacitor such as a supercapacitor element. Including.
  • the separator according to the embodiment of the present invention is a lithium secondary battery including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, or a lithium ion polymer secondary battery among the secondary batteries. It can be suitably used for secondary batteries.
  • the battery case that houses the electrode assembly may be cylindrical, square, pouch-shaped, coin-shaped, or the like.
  • the weight average molecular weight (Mw) of the copolymer was determined by gel permeation chromatography (GPC) under the following conditions.
  • -Measuring device GPC-150C manufactured by Waters Corporation -Column: Shodex UT806M manufactured by Showa Denko KK -Column temperature: 135 ° C -Solvent (mobile phase): o-dichlorobenzene-Solvent flow rate: 1.0 mL / min-Sample concentration: 0.1 wt% (dissolution condition: 135 ° C / 1h)
  • Injection volume 500 ⁇ L -Detector: Differential refractometer (RI detector) manufactured by Waters Corporation
  • Calibration curve A calibration curve was prepared from a calibration curve obtained using a monodisperse polystyrene standard sample using a predetermined conversion constant.
  • the solid content volume% of the coating solution was calculated by dividing the solid content concentration (% by mass) of the coating solution by the specific gravity of the coating solution.
  • the specific gravity (g / cm 3 ) of the coating solution was measured at 25 ° C. using the Archimedes method. That is, an appropriately selected coating liquid was weighed in a state where it was immersed in air and water (buoyancy), and the specific gravity was obtained by dividing the mass in air by buoyancy.
  • the viscosity ⁇ (mPa ⁇ s) of the coating liquid was measured at 25 ° C. using a viscometer (DVI-PRIME manufactured by BROOKFIELD).
  • the surface tension ⁇ (mN / m) was obtained by measuring the surface tension of the coating solution at 25 ° C. using the hanging drop method.
  • Water content remaining in the film A test film obtained by cutting a separator manufactured using a dumbbell cutter into 1.00 g under an environment of 23 ° C. and 65% RH is put into an apparatus, and then a water vaporizer (Kyoto Electronics Co., Ltd.) It was measured using an industrial product “ADP-611”). The measured value obtained by the measurement was defined as the water content (ppm) remaining in the separator.
  • ⁇ Measurement method for flexural strength when wet Generally, a binder of a fluorine-based resin is used for the positive electrode, and when a porous layer containing the fluorine-based resin is provided on the separator, adhesion is easily ensured by mutual diffusion between the fluorine-based resins. On the other hand, a binder other than the fluorine-based resin is used for the negative electrode, and the diffusion of the fluorine-based resin hardly occurs. Therefore, in this measurement, the adhesiveness between the separator and the negative electrode was evaluated using the flexural strength when wet as an index.
  • Negative Electrode 1 An aqueous solution containing 1.5 parts by mass of carboxymethylcellulose was added to 96.5 parts by mass of artificial graphite and mixed, and 2 parts by mass of styrene-butadiene latex as a solid content was further added and mixed. The slurry was contained. This negative electrode mixture-containing slurry is uniformly applied to both surfaces of a negative electrode current collector made of copper foil having a thickness of 8 ⁇ m, dried to form a negative electrode layer, and then compression molded by a roll press to collect current. A negative electrode 1 was produced by setting the density of the negative electrode layer excluding the body to 1.5 g / cm 3 .
  • test wound body enclosed in the laminate film 3 is sandwiched between two gaskets (1 mm thick, 5 cm ⁇ 5 cm), and is subjected to a precision heating and pressing device (CYPT-10, manufactured by Shinto Kogyo Co., Ltd.). It was pressurized at 98 ° C. and 0.6 MPa for 2 minutes and allowed to cool at room temperature. The bending strength at the time of wet was measured for the test roll after pressurization while being sealed in the laminate film 3 using a universal testing machine (AGS-J, manufactured by Shimadzu Corporation). The details are described below.
  • Two aluminum L-shaped angles 4 are arranged in parallel so that the 90 ° part is on the top, and the ends are aligned.
  • the distance was fixed so as to be 15 mm.
  • the midpoint of the side (about 25 mm) in the width direction of the test roll is aligned with the 7.5 mm point that is the middle of the distance between the fulcrums of the two aluminum L-angles 4, and the length of the L-angle is measured in the length direction.
  • the test roll was arranged so as not to protrude from the side.
  • the length (about 29 mm) in the length direction of the test wound body does not protrude from the length side of the aluminum L-shaped angle 5 (thickness 1 mm, 10 mm ⁇ 10 mm, length 4 cm) as an indenter. So that the 90 ° portion of the aluminum L-shaped angle 5 is aligned with the midpoint of the widthwise side of the test roll, and the aluminum L-shaped angle 5 is positioned so that the 90 ° portion is downward. It was fixed to a load cell (load cell capacity 100N) of a universal testing machine.
  • load cell load cell capacity 100N
  • the three test rolls were measured at a load speed of 0.5 mm / min, the average value of the obtained maximum test forces was defined as the wet bending strength, and the value obtained by dividing by the electrode width 25 mm was the wet bending strength. (N / mm). Table 1 shows the results.
  • the coating thickness d1 ( ⁇ m) was calculated by dividing the thickness of the porous layer by the solid content volume%.
  • ⁇ Groove shape measurement method A sample having a size of 10 cm ⁇ 10 cm was cut out from an arbitrary place and tautened so as not to be affected by wrinkles, thereby preparing a sample used for imaging.
  • the prepared sample was set on a white interference microscope (“VS-1540” manufactured by Hitachi High-Tech Science Co., Ltd.), the lens barrel magnification was 0.5 ⁇ , the objective lens was 5 ⁇ , and the analysis software was “VS-540 manufactured by Hitachi High-Tech Science Co., Ltd.”
  • the imaging was performed with the setting condition in the Viewer 10 ′′) set to the Wave mode.
  • the obtained image was subjected to quaternary plane correction, complete interpolation, and smoothing image processing by the analysis software.
  • the smoothing strength was 19 ⁇ 19 in the vertical and horizontal directions.
  • the pitch (mm) of the groove was measured as follows. A sample having a size of 10 cm ⁇ 10 cm was cut out from an arbitrary place and tautened so as not to be affected by wrinkles, thereby preparing a sample used for imaging. The prepared sample was set on a white interference microscope (“VS-1540” manufactured by Hitachi High-Tech Science Co., Ltd.), the lens barrel magnification was 0.5 ⁇ , the objective lens was 5 ⁇ , and the analysis software (“VS-” manufactured by Hitachi High-Tech Science Co., Ltd.) The imaging was performed with the setting condition in the Viewer 10 ′′) set to the Wave mode.
  • VS-1540 manufactured by Hitachi High-Tech Science Co., Ltd.
  • the obtained image was subjected to quaternary plane correction, complete interpolation, and smoothing image processing by the analysis software.
  • the smoothing strength was 19 ⁇ 19 in the vertical and horizontal directions.
  • the cross-sectional profile of the processed image was written out in the form of a text data file from the analysis software, plotted on spreadsheet software, the horizontal distance from the bottom of the valley to the bottom of the adjacent valley was defined as pitch, and randomly extracted. Twenty points were measured, and the average value of the measured values was used as the pitch. The imaging location was changed, and the average value of the pitch obtained five times was defined as the pitch of the groove.
  • the groove depth ( ⁇ m) was measured in the same manner as in the groove shape measuring method as follows. A sample having a size of 10 cm ⁇ 10 cm was cut out from an arbitrary place and tautened so as not to be affected by wrinkles, thereby preparing a sample used for imaging. The prepared sample was observed using a white interference microscope (“VS-1540” manufactured by Hitachi High-Tech Science Co., Ltd.) and analysis software (“VS-Viewer 10” manufactured by Hitachi High-Tech Science Co., Ltd.). Specifically, imaging was performed with a lens barrel magnification of 0.5 times, an objective lens of 5 times, and analysis software (“VS-Viewer10” manufactured by Hitachi High-Tech Science Co., Ltd.) set as Wave mode conditions.
  • VS-1540 manufactured by Hitachi High-Tech Science Co., Ltd.
  • analysis software VS-Viewer 10 manufactured by Hitachi High-Tech Science Co., Ltd.
  • the obtained image was subjected to quaternary plane correction, complete interpolation, and smoothing image processing by the analysis software.
  • the smoothing strength was 19 ⁇ 19 in the vertical and horizontal directions.
  • a cross-sectional profile of the processed image is written out in a text data file format from the analysis software, and all data (1023 points) are plotted on spreadsheet software to calculate the maximum and minimum values of the Y axis.
  • the same measurement was performed 10 times while changing the imaging location, and T 1 -T 2 was defined as the groove depth when the average value of the maximum value of the Y axis was T 1 and the average value of the minimum value was T 2 . This procedure is described in the “VS-Viewer” manual.
  • Transportability evaluation method The separator obtained in the example or the comparative example, which was slit to a width of 60 mm, was conveyed at a speed of 100 m / min and a tension of 2.5 N in the conveying system shown in FIG. The occurrence of wrinkles in the free roll portion of this transport system was classified according to the following criteria, and the results are shown in Table 1 as transport test results.
  • X When the wrinkles occurred for 45 minutes or more when continuously observed for 1 minute at an arbitrary timing.
  • ⁇ Wrinkling occurred for 15 minutes or more and less than 45 seconds when continuously observed for 1 minute at an arbitrary timing.
  • ⁇ When wrinkles occurred for less than 15 seconds when observed continuously for one minute at an arbitrary timing.
  • the angle of inclination ⁇ shown in FIG. 3 is 90 °.
  • Copolymer (a) was synthesized by the following procedure. Using vinylidene fluoride, hexafluoropropylene, and monomethyl maleate as starting materials, the molar ratio of vinylidene fluoride / hexafluoropropylene / monomethyl maleate was 98.0 / 1.5 / 0.5 by a suspension polymerization method. Thus, a copolymer was synthesized. The weight average molecular weight of the obtained copolymer was 1.2 million.
  • the copolymer (b) was synthesized by the following procedure. Using vinylidene fluoride, hexafluoropropylene and monomethyl maleate as starting materials, the molar ratio of vinylidene fluoride / hexafluoropropylene / monomethyl maleate was 96.5 / 3.0 / 0.5 by a suspension polymerization method. Thus, a copolymer was synthesized. The weight average molecular weight of the obtained copolymer was 1.5 million.
  • a coating liquid B having a volume ratio of the copolymer (b) of 50:50 was obtained.
  • the copolymer (b) was synthesized by the same procedure. 173.2 parts by mass of the obtained copolymer (b) and 5100 parts by mass of N-methyl-2-pyrrolidone are mixed, and then, while stirring with a disper, alumina particles (average particle size 0.5 ⁇ m, density 4 (0.0g / cc) 726.8 parts by mass, and the mixture was further preliminarily stirred with a disper at 2000 rpm for 1 hour. Next, using a Dyno mill (Dyno Mill Multilab manufactured by Shinmaru Enterprises Co., Ltd.
  • the copolymer (b) was synthesized by the same procedure. 143.5 parts by mass of the obtained copolymer (b) and 5100 parts by mass of N-methyl-2-pyrrolidone were mixed, and then the mixture was stirred with a disper while stirring alumina particles (average particle size 0.5 ⁇ m, density 4 (0.0g / cc) 756.5 parts by mass, and the mixture was further preliminarily stirred with a disper at 2000 rpm for 1 hour. Next, using a Dyno mill (Dyno Mill Multilab manufactured by Shinmaru Enterprises Co., Ltd.
  • the copolymer (b) was synthesized by the same procedure. 228.6 parts by mass of the obtained copolymer (b) and 5329 parts by mass of N-methyl-2-pyrrolidone were mixed, and then, with stirring with a disper, alumina particles (average particle size 0.5 ⁇ m, density 4 (0.0g / cc), 442.8 parts by mass, and the mixture was further preliminarily stirred with a disper at 2000 rpm for 1 hour. Next, using a Dyno mill (Dyno Mill Multilab manufactured by Shinmaru Enterprises Co., Ltd.
  • Example 1 A 7 ⁇ m-thick polyethylene microporous substrate was prepared, and a coating solution A was applied to both surfaces thereof by dip coating and scraped off.
  • the coating liquid A was applied by adjusting the transport speed V to 1.0 m / s, and the scraping was performed by adjusting the clearance so that the coating film thickness d1 per side was 16.7 ⁇ m, and both sides were 33.3 ⁇ m.
  • the coating solution was immersed in an aqueous solution containing 10% by mass of N-methyl-2-pyrrolidone for 10 seconds, washed with pure water, dried at 50 ° C., and the thickness of the porous layer was 1 per side.
  • a separator for electrochemical devices having a thickness of 0.8 ⁇ m and a total of 3.6 ⁇ m on both surfaces was produced.
  • the manufactured separator for an electrochemical element was evaluated in accordance with the above-described transportability evaluation method.
  • Examples 2 to 10 and Comparative Examples 1 to 3 As shown in Table 1, a separator for an electrochemical element was manufactured in the same manner as in Example 1 except that the type of the coating liquid, the transport speed V, and the coating film thickness were changed, and the transportability was evaluated.
  • Electrochemical with a porous layer that has improved electrode adhesion to improve repetitive use (life) and does not reduce the functions such as insulation and ion permeability required for electrochemical element separators Provided are an element separator and an electrochemical element provided with the same.
  • Negative electrode 2 Electrochemical element separator 3: Laminated film 4: Aluminum L-shaped angle 5: Aluminum L-shaped angle for indenter 10: Microporous substrate 20: Porous layer 30: Linear groove 100: Separator 111: Free roll 112: Unwinding part (drive) 113: Winding unit (drive)

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  • Chemical Kinetics & Catalysis (AREA)
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  • Electric Double-Layer Capacitors Or The Like (AREA)

Abstract

La présente invention est un séparateur pour un élément électrochimique, comprenant : un substrat microporeux ; et une couche poreuse qui est formée sur un côté ou sur les deux côtés du substrat microporeux, et qui inclut un mélange de particules inorganiques et un liant polymère, tel que : dans le profil dans la direction de la largeur de la configuration de section transversale de la surface de la couche poreuse mesurée par un microscope interférentiel à lumière blanche, lorsque la valeur maximale de l'axe Y est T1, que la valeur minimale est T2, que le point médian entre T1 <sb /> et T2 est T0 = (T1+T2)/2, que le nombre de points supérieurs ou égaux à T0 est P1, et que le nombre de points inférieurs à T0 est P2, la relation 0,8 ≤ P1/P2 ≤ 1,2 est satisfaite ; lorsque le nombre de points inclus dans la plage comprise entre 0,8 T1 et T1 est S1, la relation 0 < S1 ≤ 0,4 P1 est satisfaite ; et lorsque le nombre de points inclus dans la plage comprise entre 0,8 T2 et T2 est S2, 0 < S2 ≤ 0,4 P2 est satisfaite.
PCT/JP2019/035073 2018-09-06 2019-09-05 Séparateur pour élément électrochimique et élément électrochimique l'utilisant Ceased WO2020050377A1 (fr)

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WO2024181446A1 (fr) 2023-02-28 2024-09-06 住友化学株式会社 Enzyme de coupure, système d'édition d'adn, procédé d'édition d'adn cible et procédé de production de cellules dans lesquelles l'adn cible est édité
EP4674959A1 (fr) 2023-02-28 2026-01-07 Sumitomo Chemical Company, Limited Enzyme de coupure, système d'édition d'adn, procédé d'édition d'adn cible et procédé de production de cellules dans lesquelles l'adn cible est édité
WO2024221876A1 (fr) * 2023-04-24 2024-10-31 宁德时代新能源科技股份有限公司 Séparateur, élément de batterie, batterie et dispositif électrique
CN119381704A (zh) * 2024-12-27 2025-01-28 江苏卓高新材料科技有限公司 一种锂离子电池隔膜及其制备方法、锂离子电池

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