WO2020091024A1 - Non-aqueous electrolyte secondary battery - Google Patents
Non-aqueous electrolyte secondary battery Download PDFInfo
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- WO2020091024A1 WO2020091024A1 PCT/JP2019/042958 JP2019042958W WO2020091024A1 WO 2020091024 A1 WO2020091024 A1 WO 2020091024A1 JP 2019042958 W JP2019042958 W JP 2019042958W WO 2020091024 A1 WO2020091024 A1 WO 2020091024A1
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- aqueous electrolyte
- secondary battery
- porous layer
- electrolyte secondary
- inorganic filler
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
- H01M50/40—Separators; Membranes; Diaphragms; Spacing elements inside cells
- H01M50/409—Separators, membranes or diaphragms characterised by the material
- H01M50/443—Particulate material
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
- H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
- H01M10/0566—Liquid materials
- H01M10/0567—Liquid materials characterised by the additives
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
- H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
- H01M10/0566—Liquid materials
- H01M10/0569—Liquid materials characterised by the solvents
-
- 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
Definitions
- the present invention relates to a non-aqueous electrolyte secondary battery.
- Non-aqueous electrolyte secondary batteries especially lithium-ion secondary batteries, are widely used as batteries for personal computers, mobile phones, personal digital assistants, etc. because of their high energy density, and recently they have been developed as in-vehicle batteries. Has been.
- non-aqueous electrolyte secondary battery for example, a porous layer containing a plate-like inorganic filler as described in Patent Document 1 and having a porosity of 60 to 90% is provided on at least one surface of a porous substrate.
- a non-aqueous electrolyte secondary battery including a non-aqueous secondary battery separator that is laminated on.
- the present invention has been made in view of the above problems, and an object thereof is to realize a non-aqueous electrolyte secondary battery having an excellent charge capacity after high rate discharge.
- a non-aqueous electrolyte secondary battery includes a porous layer containing an inorganic filler and a resin, a non-aqueous electrolyte, a positive electrode and a negative electrode,
- the aspect ratio of the projected image of the inorganic filler on the surface of the porous layer is in the range of 1.4 to 4.0, Peak strengths of arbitrary diffraction planes (hkl) and (abc) orthogonal to each other, measured by a wide-angle X-ray diffraction method, of the porous layer: I (hkl) and I (abc) satisfy the following formula (1).
- the non-aqueous electrolyte contains 0.5 ppm or more and 300 ppm or less of an additive having an ionic conductivity reduction rate L represented by the following formula (A) of 1.0% or more and 6.0% or less.
- LA (LA-LB) / LA ... (A)
- LA was prepared by dissolving LiPF 6 in a mixed solvent containing ethylene carbonate, ethylmethyl carbonate and diethyl carbonate in a volume ratio of 3: 5: 2 such that the concentration thereof was 1 mol / L.
- the ionic conductivity (mS / cm) of the reference electrolytic solution is represented, and LB represents the ionic conductivity (mS / cm) of the electrolytic solution prepared by dissolving the additive in the reference electrolytic solution in an amount of 1.0% by weight. .
- the non-aqueous electrolyte secondary battery according to Aspect 2 of the present invention is the same as in Aspect 1, except that the porous layer is laminated on one side or both sides of the polyolefin porous film.
- the porous layer has a polyolefin, a (meth) acrylate resin, a fluorine-containing resin, a polyamide resin, a polyester resin. It includes a resin selected from the group consisting of resins and water-soluble polymers.
- the polyamide resin is an aramid resin.
- the nonaqueous electrolyte secondary battery according to Aspect 5 of the present invention is the nonaqueous electrolyte secondary battery according to any one of Aspects 1 to 4, wherein the nonaqueous electrolyte solution contains an electrolyte containing lithium.
- the non-aqueous electrolyte secondary battery according to Aspect 6 of the present invention in any one of Aspects 1 to 5, the non-aqueous electrolyte contains an aprotic polar solvent.
- non-aqueous electrolyte secondary battery having an excellent 1C charge capacity after high rate discharge (for example, 3C discharge).
- FIG. 3 is a schematic diagram showing a projected image of an inorganic filler on the surface of the porous layer for a non-aqueous electrolyte secondary battery in one embodiment of the present invention.
- a non-aqueous electrolyte secondary battery includes a porous layer described below, a positive electrode described below, a negative electrode described below, and a non-aqueous electrolytic solution described below.
- the non-aqueous electrolyte secondary battery according to the exemplary embodiment of the present invention may further include a polyolefin porous film described below.
- the porous layer in one embodiment of the present invention is a porous layer containing an inorganic filler and a resin, and the aspect ratio of the projected image of the inorganic filler on the surface of the porous layer is 1.4 to 4.0.
- the peak intensities of arbitrary diffraction planes (hkl) and (abc) of the porous layer, which are orthogonal to each other, measured by a wide-angle X-ray diffraction method: I (hkl) and I (abc) are expressed by the following formula: It is characterized in that the range of the maximum value of the peak intensity ratio, which satisfies the condition (1) and is calculated by the following formula (2), is in the range of 1.5 to 300.
- the surface of the said porous layer may be called a "porous layer surface.” I (hkl) > I (abc) ... (1), I (hkl) / I (abc) (2).
- the porous layer may be disposed between the polyolefin porous film and at least one of the positive electrode and the negative electrode as a member constituting the non-aqueous electrolyte secondary battery.
- the porous layer may be formed on one side or both sides of the polyolefin porous film.
- the porous layer may be formed on the active material layer of at least one of the positive electrode and the negative electrode.
- the porous layer may be arranged between the polyolefin porous film and at least one of the positive electrode and the negative electrode so as to be in contact with them.
- the porous layer arranged between the polyolefin porous film and at least one of the positive electrode and the negative electrode may be one layer or two or more layers.
- the porous layer is preferably an insulating porous layer containing a resin.
- the porous layer is laminated on one side of the polyolefin porous film
- the porous layer is preferably laminated on the surface of the polyolefin porous film facing the positive electrode. More preferably, the porous layer is laminated on the surface in contact with the positive electrode.
- FIG. 1 shows a schematic diagram of the state of the inorganic filler in the porous layer when the orientation is high and when the orientation is low.
- the left diagram of FIG. 1 is a schematic diagram showing the structure of the porous layer containing an inorganic filler when the orientation of the filler is large and the anisotropy is high, and the right diagram of FIG. 1 is the inorganic layer. It is a schematic diagram showing the structure of the said porous layer in case the orientation of a filler is small and anisotropy is low.
- the porous layer in one embodiment of the present invention contains an inorganic filler and a resin.
- the porous layer has a large number of pores inside and has a structure in which these pores are connected, and is a layer through which gas or liquid can pass from one surface to the other surface.
- the porous layer in one embodiment of the present invention is used as a member constituting a non-aqueous electrolyte secondary battery laminated separator described below, the porous layer is an electrode as an outermost layer of the laminated separator. Can be a layer in contact with.
- the resin contained in the porous layer in one embodiment of the present invention is preferably insoluble in the electrolytic solution of the battery and is electrochemically stable in the usage range of the battery.
- the resin include polyolefins; (meth) acrylate resins; fluorine-containing resins; polyamide resins; polyimide resins; polyester resins; rubbers; melting points or glass transition temperatures of 180 ° C. or higher.
- Resins water-soluble polymers; polycarbonates, polyacetals, polyether ether ketones and the like.
- polyolefins polyolefins, polyester resins, (meth) acrylate resins, fluorine-containing resins, polyamide resins and water-soluble polymers are preferable.
- polyethylene polyethylene, polypropylene, polybutene, ethylene-propylene copolymer and the like are preferable.
- polyamide resin aramid resins such as aromatic polyamide and wholly aromatic polyamide are preferable.
- the aramid resin examples include poly (paraphenylene terephthalamide), poly (metaphenylene isophthalamide), poly (parabenzamide), poly (metabenzamide), poly (4,4′-benzanilide terephthalate). Amide), poly (paraphenylene-4,4′-biphenylenedicarboxylic acid amide), poly (metaphenylene-4,4′-biphenylenedicarboxylic acid amide), poly (paraphenylene-2,6-naphthalenedicarboxylic acid amide), Poly (metaphenylene-2,6-naphthalenedicarboxylic acid amide), poly (2-chloroparaphenylene terephthalamide), paraphenylene terephthalamide / 2,6-dichloroparaphenylene terephthalamide copolymer, metaphenylene terephthalamide / 2 , 6-diclosure Paraphenylene terephthalamide copolymer and the like. Of these, poly (paraphenylene
- polyester resin aromatic polyester such as polyarylate and liquid crystal polyester are preferable.
- Examples of rubbers include styrene-butadiene copolymer and its hydride, methacrylic acid ester copolymer, acrylonitrile-acrylic acid ester copolymer, styrene-acrylic acid ester copolymer, ethylene propylene rubber, polyvinyl acetate and the like. Can be mentioned.
- Examples of the resin having a melting point or glass transition temperature of 180 ° C. or higher include polyphenylene ether, polysulfone, polyether sulfone, polyphenylene sulfide, polyetherimide, polyamideimide, and polyetheramide.
- water-soluble polymers examples include polyvinyl alcohol, polyethylene glycol, cellulose ether, sodium alginate, polyacrylic acid, polyacrylamide, polymethacrylic acid and the like.
- fluorine-containing resin examples include polyvinylidene fluoride (PVDF), polytetrafluoroethylene, vinylidene fluoride-hexafluoropropylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer Coalescence, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-trichloroethylene copolymer, vinylidene fluoride-vinyl fluoride copolymer, vinylidene fluoride-hexafluoro Among them, propylene-tetrafluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer and the like, and fluorine-containing rubber having a glass transition temperature of 23 ° C. or lower among the
- the resin contained in the porous layer in the embodiment of the present invention may be one kind or a mixture of two or more kinds.
- a fluorine-containing resin is preferable because it can be easily maintained.
- the porous layer in one embodiment of the present invention contains an inorganic filler.
- the lower limit of the content is preferably 50% by weight or more and 70% by weight or more based on the total weight of the filler and the resin constituting the porous layer in the embodiment of the present invention. More preferably, it is more preferably 90% by weight or more.
- the upper limit of the content of the inorganic filler in the porous layer in the embodiment of the present invention is preferably 99% by weight or less, and more preferably 98% by weight or less.
- the content of the filler is preferably 50% by weight or more from the viewpoint of heat resistance, and the content of the filler is preferably 99% by weight or less from the viewpoint of adhesion between the fillers.
- the inorganic filler is not particularly limited as long as it is a filler that is stable in a non-aqueous electrolytic solution and is electrochemically stable. From the viewpoint of ensuring the safety of the battery, a filler having a heat resistant temperature of 150 ° C. or higher is preferable.
- the inorganic filler is not particularly limited, but is usually an insulating filler.
- the inorganic filler is preferably an inorganic material containing at least one metal element selected from the group consisting of aluminum element, zinc element, calcium element, zirconia element, silicon element, magnesium element, barium element, and boron element, It is preferably an inorganic substance containing an aluminum element. Further, the inorganic filler preferably contains an oxide of the metal element.
- the inorganic filler titanium oxide, alumina (Al 2 O 3 ), zinc oxide (ZnO), calcium oxide (CaO), zirconia oxide (ZrO 2 ), silica, magnesia, barium oxide, boron oxide, Examples thereof include mica, wollastonite, attapulgite, and boehmite (alumina monohydrate).
- the inorganic filler one kind of filler may be used alone, or two or more kinds of filler may be used in combination.
- the inorganic filler in the porous layer in one embodiment of the present invention preferably contains alumina and a plate-like filler.
- the plate-like filler include one or more fillers selected from the group consisting of zinc oxide (ZnO), mica, and boehmite among the oxides of the metal elements listed above.
- the volume average particle size of the inorganic filler is preferably in the range of 0.01 ⁇ m to 10 ⁇ m from the viewpoint of ensuring good adhesiveness and slipperiness, and moldability of the laminate.
- the lower limit value is more preferably 0.05 ⁇ m or more, further preferably 0.1 ⁇ m or more.
- the upper limit value is more preferably 5 ⁇ m or less, further preferably 1 ⁇ m or less.
- the shape of the inorganic filler is arbitrary and is not particularly limited.
- the shape of the inorganic filler may be a particle shape, for example, a spherical shape; an elliptical shape; a plate shape; a rod shape; an indefinite shape; a fibrous shape; a spherical or columnar single particle such as a peanut shape and / or a tetrapot shape.
- the shape may be any of the above.
- the inorganic filler is preferably plate-like particles and / or non-aggregated primary particles.
- the shape of the inorganic filler is such that the particles in the porous material are difficult to be most closely packed, voids are easily formed between the particles, bumps, dents, constrictions, ridges or bulges, and dendritic
- a single particle is heat-fused such as an indeterminate shape such as a shape, a coral shape, or a tuft shape; a fibrous shape; a peanut shape and / or a tetrapot shape.
- the shape of the inorganic filler is particularly preferably a shape in which spherical or columnar single particles such as peanut-shaped and / or tetrapot-shaped particles are heat-sealed.
- the filler can improve slipperiness by forming fine irregularities on the surface of the porous layer.
- the filler is a plate-like particle and / or a primary particle that is not aggregated, the unevenness formed on the surface of the porous layer by the filler becomes finer, and the adhesiveness between the porous layer and the electrode is further improved. It will be good.
- the oxygen atom mass percentage of the metal oxide constituting the inorganic filler contained in the porous layer in one embodiment of the present invention is preferably 10% to 50%, more preferably 20% to 50%. preferable.
- the affinity between the solvent or the dispersion medium in the coating liquid used in the method for producing a porous layer described later and the inorganic filler is preferably adjusted. It is possible to maintain the distance between the above-mentioned inorganic fillers at an appropriate distance. Thereby, the dispersibility of the coating liquid can be improved, and as a result, the "aspect ratio of the projected image of the inorganic filler on the surface of the porous layer" and the "orientation degree of the porous layer” can be defined appropriately.
- the range can be controlled.
- the aspect ratio of the inorganic filler itself contained in the porous layer in the embodiment of the present invention is such that, in a state where the inorganic filler is arranged on a plane, in the SEM image observed from vertically above the arrangement surface, the aspect ratio overlaps in the thickness direction. It is expressed as the average value of the ratio of the length of the minor axis (minor axis diameter) to the length of the major axis (minor axis diameter) of 100 particles that are not present.
- the aspect ratio of the inorganic filler itself is preferably 1 to 10, more preferably 1.1 to 8, and even more preferably 1.2 to 5.
- the aspect ratio of the inorganic filler itself is in the above range
- the porous layer in one embodiment of the present invention is formed by the method described below, in the resulting porous layer, the orientation and porosity of the filler are It is possible to control the uniformity of the distribution of the filler on the surface of the quality layer in a preferable range.
- the porous layer in one embodiment of the present invention may contain other components than the above-mentioned inorganic filler and resin.
- the other components include surfactants, waxes and binder resins.
- the content of the other components is preferably 0% by weight to 50% by weight based on the weight of the entire porous layer.
- the average film thickness of the porous layer in one embodiment of the present invention is preferably in the range of 0.5 ⁇ m to 10 ⁇ m per one layer of the porous layer from the viewpoint of ensuring adhesiveness to the electrode and high energy density. More preferably, it is in the range of 1 ⁇ m to 5 ⁇ m.
- the basis weight per unit area of the porous layer can be appropriately determined in consideration of the strength, film thickness, weight and handling property of the porous layer.
- the basis weight per unit area of the porous layer is preferably 0.5 to 20 g / m 2 and more preferably 0.5 to 10 g / m 2 per porous layer.
- the weight energy density and volume energy density of the non-aqueous electrolyte secondary battery can be increased.
- the basis weight of the porous layer exceeds the above range, the non-aqueous electrolyte secondary battery tends to be heavy.
- the porosity of the porous layer is preferably 20 to 90% by volume, and more preferably 30 to 80% by volume so that sufficient ion permeability can be obtained.
- the pore size of the pores of the porous layer is preferably 1.0 ⁇ m or less, more preferably 0.5 ⁇ m or less. By setting the pore diameters to these sizes, the non-aqueous electrolyte secondary battery can obtain sufficient ion permeability.
- the aspect ratio of the projected image of the inorganic filler on the surface of the porous layer is in the range of 1.4 to 4.0 and is 1.5 to 2.3. It is preferably in the range.
- a scanning electron microscope (SEM) is used to take an SEM image, which is an electron micrograph of the surface, immediately above the porous layer, that is, from above the vertical direction. It is a value obtained by creating a projected image of the filler and calculating the ratio of the major axis length / minor axis length of the projected image of the inorganic filler.
- the length of the major axis is also referred to as the major axis diameter
- the length of the minor axis is also referred to as the minor axis diameter. That is, the aspect ratio refers to the shape of the inorganic filler observed when the inorganic filler on the surface of the porous layer is observed from directly above the porous layer.
- FIG. 2 shows a schematic diagram of a projected image of the inorganic filler created from the SEM image of the surface of the porous layer described above.
- the “surface” of the porous layer means the surface of the porous layer that can be observed by SEM from directly above the porous layer.
- an SEM at an accelerating voltage of 5 kV is used from directly above the porous side of the laminated body by using a field emission scanning electron microscope JSM-7600F manufactured by JEOL Ltd.
- the aspect ratio of the projected image of the inorganic filler on the surface of the porous layer is an index showing the uniformity of the distribution of the inorganic filler on the porous layer, especially on the surface thereof.
- the aspect ratio is close to 1, it means that the constituent material on the surface of the porous layer has a uniform shape and distribution, and is easily packed densely.
- the aspect ratio is large, the arrangement of the constituent components in the surface structure of the porous layer becomes non-uniform, and as a result, the uniformity of the shape and distribution of the openings of the surface of the porous layer deteriorates.
- the aspect ratio is greater than 4.0, it is considered that the uniformity of the shape and distribution of the porous layer, especially the surface openings, is excessively reduced. Therefore, in the non-aqueous electrolyte secondary battery incorporating the porous layer, a portion where the electrolyte receiving capacity of the porous layer at the time of battery operation is reduced occurs, as a result, the rate of the non-aqueous electrolyte secondary battery. It is considered that the characteristics are degraded.
- the aspect ratio is less than 1.4, the porous layer, in particular, the distribution of the inorganic filler on the surface thereof has an excessively uniform structure, and as a result, the surface opening area of the porous layer is small. It will be smaller.
- the electrolyte receiving ability of the porous layer at the time of battery operation is reduced, as a result, the battery rate characteristics of the non-aqueous electrolyte secondary battery It is expected to decrease.
- the porous layer according to one embodiment of the present invention has a peak intensity of arbitrary diffraction planes (hkl), (abc) orthogonal to each other in the porous layer measured by a wide-angle X-ray diffraction method: I (hkl) and I It is preferable that (abc) satisfies the following formula (1) and the maximum value of the peak intensity ratio calculated by the following formula (2) is in the range of 1.5 to 300, preferably 1.5 to 300. The range of 250 is more preferable. I (hkl) > I (abc) ... (1), I (hkl) / I (abc) (2).
- the maximum value of the peak intensity ratio calculated by the above formula (2) is also referred to as “the orientation degree of the porous layer”.
- the method for measuring the peak intensities I (hkl) and I (abc) and the peak intensity ratio I (hkl) / I (abc) is not particularly limited.
- the following (1) to (3) are used.
- a method comprising the steps shown can be mentioned.
- (1) A step of preparing a measurement sample by cutting a 2 cm square laminate (laminated porous film) obtained by laminating a porous layer on a substrate.
- the measurement sample obtained in step (1) was attached to an Al holder with the porous layer side of the sample as the measurement surface, and an X-ray profile was obtained by a wide-angle X-ray diffraction method (2 ⁇ - ⁇ scan method). Measuring step.
- the device for measuring the X-ray profile and the measurement conditions are not particularly limited.
- RU-200R rotating anticathode type
- CuK ⁇ rays are used as the X-ray source.
- the output may be measured at 50 KV-200 mA and a scanning speed of 2 ° / min.
- step (3) Based on the X-ray profile obtained in step (2), peak intensity I (hkl) of arbitrary diffraction planes (hkl) and (abc) orthogonal to each other in wide-angle X-ray diffraction measurement of the porous layer And I (abc) satisfy the equation (1), the peak intensity ratio calculated by the equation (2) is calculated, and the maximum value of the peak intensity ratio, that is, the degree of orientation of the porous layer is calculated. Process.
- the maximum value of the peak intensity ratio shown by the above formula (2) is an index showing the degree of orientation inside the porous layer.
- a small peak intensity ratio represented by the formula (2) means that the degree of orientation in the internal structure of the porous layer is low, and a large peak intensity ratio represented by the formula (2) means that It shows that the internal structure of the texture layer has a high degree of orientation.
- the maximum value of the peak intensity ratio represented by the formula (2) is larger than 300, the anisotropy of the internal structure of the porous layer becomes excessively high, and the ion permeation flow channel length inside the porous layer is increased. become longer. As a result, in the non-aqueous electrolyte secondary battery incorporating the porous layer, it is considered that the ion permeation resistance of the porous layer increases and the battery rate characteristics of the non-aqueous electrolyte secondary battery deteriorate.
- the maximum value of the peak intensity ratio represented by the above formula (2) is less than 1.5, compared to the case where the porous layer having the peak intensity ratio of 1.5 or more is used,
- the ions supplied from the electrodes are permeated at high speed.
- the ion supply from the electrode is rate-determining, that is, the ions are depleted on the electrode surface, the limiting current that is the battery operating current value condition becomes small, and as a result, the non-aqueous electrolyte secondary battery It is considered that the battery rate characteristic deteriorates.
- the method for producing the porous layer according to the embodiment of the present invention is not particularly limited, but for example, one of the following steps (1) to (3) may be used on the substrate, A method of forming a porous layer containing the inorganic filler and the resin can be mentioned.
- the porous layer can be produced by depositing the resin and then drying it to remove the solvent.
- the coating liquid in steps (1) to (3) may be in a state in which the inorganic filler is dispersed and the resin is dissolved.
- the solvent can be said to be a solvent for dissolving the resin and a dispersion medium for dispersing the resin or the inorganic filler.
- a step of forming a porous layer by applying a coating liquid containing the inorganic filler and fine particles of the resin on a base material and drying and removing the solvent in the coating liquid.
- the liquid property of the coating liquid is made acidic by using a low-boiling organic acid, A step of depositing a resin to form a porous layer.
- the solvent does not adversely affect the base material, dissolves the resin uniformly and stably, and disperses the inorganic filler uniformly and stably.
- the solvent include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, acetone and water.
- the deposition solvent for example, isopropyl alcohol or t-butyl alcohol is preferably used.
- the low boiling point organic acid for example, paratoluenesulfonic acid, acetic acid, etc. can be used.
- the orientation of the porous layer in one embodiment of the present invention that is, the “aspect ratio of the projected image of the inorganic filler on the surface of the porous layer” and the “degree of orientation of the porous layer”
- the solid content concentration of the coating liquid containing the inorganic filler and the resin, and the coating shear rate when coating the coating liquid on the substrate The adjustment can be mentioned.
- a suitable solid content concentration of the coating liquid may vary depending on the type of filler, etc., but generally it is preferably more than 20% by weight and 40% by weight or less. That the solid content concentration is in the above range, the viscosity of the coating liquid is appropriately maintained, and as a result, the “aspect ratio of the projected image of the inorganic filler on the surface of the porous layer” and the “degree of orientation of the porous layer”. Is preferable because it can be controlled within the above-mentioned preferable range.
- the coating shear rate at the time of applying the coating liquid on the substrate may vary depending on the type of filler, etc., but generally it is preferably 2 (1 / s) or more and 4 (1 / s). More preferably, it is from s) to 50 (1 / s).
- the inorganic filler a shape in which spherical or columnar single particles such as peanut-shaped and / or tetrapot-shaped are heat-fused, spherical-shaped, elliptical-shaped, plate-shaped, rod-shaped, or irregular-shaped.
- the coating shear rate is increased, a high shearing force is applied to the inorganic filler, so that the anisotropy tends to increase.
- the coating shear rate is reduced, the shearing force is not applied to the inorganic filler, so that the inorganic filler tends to be oriented isotropically.
- the inorganic filler is a long fiber diameter inorganic filler such as long wollastonite having a large fiber diameter
- the coating shear rate is increased, the long fibers are entangled with each other, or the long blades of the doctor blade are long fibers. Tend to be in a disoriented orientation due to the trapping of the, and anisotropy tends to be low.
- the coating shear rate is reduced, the long fibers do not become entangled with each other and do not get caught by the blade of the doctor blade, so that they tend to be oriented and the anisotropy tends to increase.
- the non-aqueous electrolyte in one embodiment of the present invention contains an additive having an ionic conductivity decrease rate L represented by the following formula (A) of 1.0% or more and 6.0% or less, 0.5 ppm to 300 ppm. contains.
- L (LA-LB) / LA ...
- LA is a reference in which LiPF 6 is dissolved in a mixed solvent containing ethylene carbonate, ethylmethyl carbonate and diethyl carbonate in a volume ratio of 3: 5: 2 so that the concentration becomes 1 mol / L.
- the ionic conductivity (mS / cm) of the electrolyte for use is shown.
- LB represents the ionic conductivity (mS / cm) of the electrolytic solution prepared by dissolving 1.0% by weight of the additive in the reference electrolytic solution.
- the additive is not particularly limited as long as it is a compound that satisfies the ionic conductivity reduction rate L represented by the formula (A) of 1.0% or more and 6.0% or less.
- examples of such a compound include pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], triethyl phosphate, vinylene carbonate, propane sultone, 2,6-dione.
- the non-aqueous electrolytic solution contains an electrolyte and an organic solvent.
- the electrolyte include an electrolyte containing lithium.
- the electrolyte containing lithium for example, LiClO 4, LiPF 6, LiAsF 6, LiSbF 6, LiBF 4, LiCF 3 SO 3, LiN (CF 3 SO 2) 2, LiC (CF 3 SO 2) 3, Examples thereof include metal salts such as Li 2 B 10 Cl 10 , lithium salts of lower aliphatic carboxylic acids and lithium salts such as LiAlCl 4 .
- the electrolyte may be used alone or in combination of two or more kinds.
- organic solvent examples include carbonates, ethers, esters, nitriles, amides, carbamates and sulfur-containing compounds, and fluorine groups introduced into these organic solvents.
- An aprotic polar solvent such as a fluorine-containing organic solvent may be used.
- the organic solvent may be used alone or in combination of two or more.
- the organic solvent is preferably a mixed solvent containing a cyclic compound such as ethylene carbonate and a chain compound such as ethylmethyl carbonate and diethyl carbonate.
- the mixed solvent contains the cyclic compound and the chain compound preferably in a volume ratio of 2: 8 to 4: 6, more preferably in a volume ratio of 2: 8 to 3: 7, and particularly preferably. Is included in a volume ratio of 3: 7.
- the mixed solvent in which the cyclic compound and the chain compound are mixed at a volume ratio of 3: 7 is an organic solvent that is generally used in the non-aqueous electrolyte solution of the non-aqueous electrolyte secondary battery.
- the additive in one embodiment of the present invention reduces the ionic conductivity of the reference electrolyte solution.
- the following reasons can be considered as reasons why the reduction of the charge capacity after high-rate discharge can be suppressed by adding the additive to the non-aqueous electrolyte solution.
- the dissociation degree of ions in the non-aqueous electrolyte may be reduced. This can reduce the depletion of ions at the interface between the separator and the electrode during charge / discharge, particularly when the battery is operated at high speed. Therefore, it is considered that the reduction of the charge capacity after the high rate discharge can be suppressed.
- the non-aqueous electrolyte solution contains the additive in an amount of 0.5 ppm or more, preferably 20 ppm or more, and more preferably 45 ppm or more.
- the non-aqueous electrolyte contains the additive in an amount of 300 ppm or less, preferably 250 ppm or less, and 180 ppm or less. Is more preferable.
- the degree of ion dissociation in the vicinity of the positive electrode during repeated charging and discharging, particularly when the battery is operated at a high speed It is strongly influenced by the amount of additives.
- the nonaqueous electrolyte secondary battery according to the embodiment of the present invention can suitably reduce the degree of dissociation of ions near the positive electrode regardless of the type of the nonaqueous electrolyte. That is, regardless of the type and amount of the electrolyte contained in the non-aqueous electrolytic solution, and the type of the organic solvent contained, the addition of 0.5 ppm or more and 300 ppm or less of the additive causes dissociation of ions near the positive electrode.
- the degree can be suitably reduced. As a result, it is possible to suppress a decrease in charge capacity after high rate discharge.
- non-aqueous electrolytic Examples include a method of pre-dissolving the additive in the non-aqueous electrolyte solution to be injected into the container that will be the housing of the liquid secondary battery, so that the content of the additive is 0.5 ppm or more and 300 ppm or less. it can.
- the positive electrode in one embodiment of the present invention is not particularly limited as long as it is generally used as the positive electrode of a non-aqueous electrolyte secondary battery.
- a positive electrode sheet having a structure in which an active material layer containing a positive electrode active material and a binder is formed on a positive electrode current collector can be used as the positive electrode.
- the active material layer may further contain a conductive agent.
- the positive electrode active material includes, for example, a material capable of being doped / dedoped with metal ions such as lithium ions or sodium ions.
- metal ions such as lithium ions or sodium ions.
- Specific examples of the material include a lithium composite oxide containing at least one transition metal such as V, Mn, Fe, Co, and Ni.
- Examples of the conductive agent include natural graphite, artificial graphite, cokes, carbon black, pyrolytic carbons, carbon fibers and carbonaceous materials such as organic polymer compound fired bodies.
- the conductive agent may be used alone or in combination of two or more kinds.
- binder examples include fluororesin such as polyvinylidene fluoride (PVDF), acrylic resin, and styrene-butadiene rubber.
- PVDF polyvinylidene fluoride
- acrylic resin acrylic resin
- styrene-butadiene rubber examples include fluororesin such as polyvinylidene fluoride (PVDF), acrylic resin, and styrene-butadiene rubber.
- the binder also has a function as a thickener.
- Examples of the positive electrode current collector include conductors such as Al, Ni and stainless steel. Among them, Al is more preferable because it is easily processed into a thin film and is inexpensive.
- the positive electrode sheet may be produced, for example, by pressure molding a positive electrode active material, a conductive agent and a binder on a positive electrode current collector; a positive electrode active material, a conductive agent and a binder using an appropriate organic solvent. Is applied to a positive electrode current collector, dried, and then pressed to fix it to the positive electrode current collector; and the like.
- the negative electrode in one embodiment of the present invention is not particularly limited as long as it is generally used as a negative electrode of a non-aqueous electrolyte secondary battery.
- a negative electrode sheet having a structure in which an active material layer containing a negative electrode active material and a binder is formed on a negative electrode current collector can be used as the negative electrode.
- the active material layer may further contain a conductive agent.
- the negative electrode active material for example, a material capable of doping / dedoping metal ions such as lithium ions or sodium ions can be mentioned.
- the material include a carbonaceous material and the like.
- the carbonaceous material include natural graphite, artificial graphite, cokes, carbon black and pyrolytic carbons.
- Examples of the negative electrode current collector include Cu, Ni and stainless steel.
- Cu is more preferable because it is difficult to form an alloy with lithium and is easily processed into a thin film.
- Examples of the method for producing the negative electrode sheet include a method in which the negative electrode active material is pressure-molded on the negative electrode current collector; the negative electrode active material is made into a paste using an appropriate organic solvent, and then the paste is used as the negative electrode current collector. And the like, and then pressurizing and fixing to the negative electrode current collector; and the like.
- the paste preferably contains the conductive agent and the binder.
- the non-aqueous electrolyte secondary battery in one embodiment of the present invention may include a polyolefin porous film.
- a polyolefin porous film may only be called a "porous film.”
- the porous film contains a polyolefin-based resin as a main component and has a large number of pores connected to the inside thereof, so that a gas and a liquid can pass from one surface to the other surface.
- the porous film alone can serve as a separator for a non-aqueous electrolyte secondary battery. It can also be a base material of the laminated separator for a non-aqueous electrolyte secondary battery in which the above-mentioned porous layer is laminated.
- a laminate in which the porous layer is laminated in the present specification, also referred to as "non-aqueous electrolyte secondary battery laminated separator” or “laminated separator” .
- the separator for a non-aqueous electrolyte secondary battery in one embodiment of the present invention may further include other layers such as an adhesive layer, a heat resistant layer, and a protective layer, in addition to the polyolefin porous film.
- the proportion of polyolefin in the porous film is 50% by volume or more of the entire porous film, more preferably 90% by volume or more, and further preferably 95% by volume or more. Further, it is more preferable that the polyolefin contains a high molecular weight component having a weight average molecular weight of 5 ⁇ 10 5 to 15 ⁇ 10 6 . In particular, when the polyolefin contains a high molecular weight component having a weight average molecular weight of 1,000,000 or more, the strength of the separator for a non-aqueous electrolyte secondary battery is improved, which is more preferable.
- the polyolefin which is a thermoplastic resin
- a copolymer may be used.
- the homopolymer include polyethylene, polypropylene and polybutene.
- the copolymer include ethylene-propylene copolymer.
- polyethylene is more preferable because it can block excessive current from flowing at lower temperatures. Note that blocking the flow of this excessive current is also referred to as shutdown.
- the polyethylene include low density polyethylene, high density polyethylene, linear polyethylene (ethylene- ⁇ -olefin copolymer), and ultrahigh molecular weight polyethylene having a weight average molecular weight of 1,000,000 or more. Among these, ultrahigh molecular weight polyethylene having a weight average molecular weight of 1,000,000 or more is more preferable.
- the thickness of the porous film is preferably 4 to 40 ⁇ m, more preferably 5 to 30 ⁇ m, and further preferably 6 to 15 ⁇ m.
- the basis weight per unit area of the porous film can be appropriately determined in consideration of strength, film thickness, weight and handleability.
- the basis weight is preferably 4 to 20 g / m 2 , and preferably 4 to 12 g / m 2 so that the weight energy density and the volume energy density of the non-aqueous electrolyte secondary battery can be increased. More preferably, it is more preferably 5 to 10 g / m 2 .
- the air permeability of the porous film is preferably 30 to 500 sec / 100 mL in Gurley value, and more preferably 50 to 300 sec / 100 mL.
- the air permeability of the laminated separator for a non-aqueous electrolyte secondary battery in which the above-mentioned porous layer is laminated on the porous film is preferably 30 to 1000 sec / 100 mL in terms of Gurley value, and is 50 to 800 sec / 100 mL. Is more preferable. Since the laminated separator for a non-aqueous electrolyte secondary battery has the above-mentioned air permeability, it is possible to obtain sufficient ion permeability in the non-aqueous electrolyte secondary battery.
- the porosity of the porous film is preferably 20 to 80% by volume so as to increase the holding amount of the electrolytic solution and to surely prevent the flow of an excessive current at a lower temperature. It is more preferably 30 to 75% by volume.
- the pore size of the pores of the porous film is 0.3 ⁇ m or less so that sufficient ion permeability can be obtained and particles can be prevented from entering the positive electrode and the negative electrode. Is preferable, and 0.14 ⁇ m or less is more preferable.
- the method for producing the polyolefin porous film is not particularly limited.
- a sheet-shaped polyolefin resin composition is prepared by kneading a polyolefin resin, a pore-forming agent such as an inorganic filler and a plasticizer, and optionally an antioxidant and the like and then extruding the kneaded product.
- the polyolefin resin composition from which the pore-forming agent has been removed may be stretched to produce a polyolefin porous film. it can.
- the above-mentioned inorganic filler is not particularly limited, and examples thereof include inorganic fillers, specifically calcium carbonate and the like.
- the plasticizer is not particularly limited, and examples thereof include low molecular weight hydrocarbons such as liquid paraffin.
- a method including the following steps can be mentioned.
- A a step of kneading an ultrahigh molecular weight polyethylene, a low molecular weight polyethylene having a weight average molecular weight of 10,000 or less, a pore forming agent such as calcium carbonate or a plasticizer, and an antioxidant to obtain a polyolefin resin composition
- B a step of rolling the obtained polyolefin resin composition with a pair of rolling rollers and gradually cooling it while pulling it with a take-up roller having a different speed ratio to form a sheet
- C a step of removing the pore forming agent from the obtained sheet with a suitable solvent
- D A step of stretching the sheet from which the pore forming agent has been removed at an appropriate stretching ratio.
- Method for producing laminated separator for non-aqueous electrolyte secondary battery examples include, for example, in the above-mentioned “method for producing a porous layer”, as the base material to which the coating liquid is applied, The method of using a polyolefin porous film can be mentioned.
- the porous layer is laminated on one side or both sides of the polyolefin porous film to obtain a non-aqueous electrolyte secondary battery laminated separator.
- Non-aqueous electrolyte secondary battery As a method for manufacturing the non-aqueous electrolyte secondary battery according to the embodiment of the present invention, a conventionally known manufacturing method can be adopted. For example, by arranging the positive electrode, the polyolefin porous film, and the negative electrode in this order, a member for a non-aqueous electrolyte secondary battery is formed.
- the porous layer may be present between the polyolefin porous film and at least one of the positive electrode and the negative electrode.
- the member for a non-aqueous electrolyte secondary battery is put in a container which is a casing of the non-aqueous electrolyte secondary battery. After filling the inside of the container with the non-aqueous electrolyte, the container is sealed while reducing the pressure. Thereby, the non-aqueous electrolyte secondary battery according to the embodiment of the present invention can be manufactured.
- Film thickness (unit: ⁇ m) The thickness of the polyolefin porous film and the porous layer was measured using a high precision digital length measuring machine (VL-50) manufactured by Mitutoyo Corporation. The film thickness of the porous layer was a value obtained by subtracting the film thickness of the part where the porous layer was not formed from the film thickness of the part where the porous layer was formed in each laminate.
- An OHP film was placed on the obtained SEM image to create a projected image laid out along the contours of the particles of the inorganic filler, and the projected image was taken by a digital still camera.
- the obtained photograph data was loaded into a computer, and the aspect ratio of each of 100 particles was calculated using free image analysis software IMAGEJ published by the National Institutes of Health (NIH).
- NASH National Institutes of Health
- each filler particle was approximated to an ellipse, the major axis diameter and the minor axis diameter were calculated, and the value obtained by dividing the major axis diameter by the minor axis diameter was taken as the aspect ratio per filler.
- the average was taken as the aspect ratio of the projected image of the inorganic filler on the surface of the porous layer in the porous layer.
- the aspect ratio is also referred to as a surface filler aspect ratio.
- the peak intensities I (hkl) and I (abc) of arbitrary diffraction planes (hkl) and (abc) orthogonal to each other in the wide-angle X-ray diffraction measurement of the porous layer are represented by the following formula (1 ).
- the peak intensity ratio calculated by I (hkl) / I (abc) in the case of satisfying (1) is calculated, and the maximum value of the peak intensity ratio is calculated. I (hkl) > I (abc) ... (1).
- Reduction rate of ionic conductivity (%) LiPF 6 was dissolved in a mixed solvent prepared by mixing ethylene carbonate, ethylmethyl carbonate and diethyl carbonate in a volume ratio of 3: 5: 2 to a concentration of 1 mol / L to prepare a reference electrolyte solution. Obtained. Each additive was added to the reference electrolyte solution to be 1% and dissolved, and then the ionic conductivity (mS / cm) was measured. The ionic conductivity was measured using an electric conductivity meter (ES-71) manufactured by Horiba Ltd. The ionic conductivity decrease rate is represented by the following formula (A).
- L (LA-LB) / LA ... (A) L: reduction rate of ionic conductivity (%), LA: ionic conductivity (mS / cm) before addition, LB: Ionic conductivity (mS / cm) after addition.
- a non-aqueous electrolyte secondary battery assembled as described below was operated at 25 ° C. in a voltage range of 4.1 to 2.7 V and a charging current value of 0.2 C.
- the CC-CV charging (final current condition 0.02C) and the CC discharging having a discharge current value of 0.2C were set as one cycle, and the initial charge / discharge for four cycles was performed at 25 ° C.
- CC-CV charging is a charging method in which charging is performed with a set constant current, and after reaching a predetermined voltage, the current is reduced while maintaining the voltage.
- CC discharge is a method of discharging to a predetermined voltage with a set constant current. The same applies to the following.
- CC-CV charging with a charging current value of 1C (end current condition 0.02C), discharging current values of 0.2C, 1C, and 3C were applied to the non-aqueous electrolyte secondary battery subjected to the initial charge / discharge in the order of CC.
- a discharge was performed.
- Charging / discharging was performed for 3 cycles at 55 ° C. for each rate.
- the voltage range was set to 2.7V to 4.2V.
- the charge capacity at the time of 1C charge in the third cycle at the time of measuring the 3C discharge rate characteristic was measured and taken as the charge capacity after high rate discharge.
- the designed capacity of the non-aqueous electrolyte secondary batteries manufactured in Examples and Comparative Examples was 20.5 mAh.
- a separator for a non-aqueous electrolyte secondary battery was produced using polyethylene. Specifically, 70 parts by weight of ultra high molecular weight polyethylene powder (340M, manufactured by Mitsui Chemicals, Inc.) and 30 parts by weight of polyethylene wax having a weight average molecular weight of 1000 (FNP-0115, manufactured by Nippon Seiro Co., Ltd.) are mixed. To obtain mixed polyethylene.
- ultra high molecular weight polyethylene powder (340M, manufactured by Mitsui Chemicals, Inc.)
- FNP-0115 polyethylene wax having a weight average molecular weight of 1000
- this polyethylene resin composition was rolled by a pair of rollers whose surface temperature was set to 150 ° C. to prepare a sheet.
- This sheet was immersed in an aqueous hydrochloric acid solution prepared by mixing 0.5 mol% of a nonionic surfactant in 4 mol / L hydrochloric acid to dissolve and remove calcium carbonate.
- seat was stretched 6 times at 105 degreeC, and the polyolefin porous film was produced.
- the porosity of the polyolefin porous film was 53%, the basis weight was 7 g / m 2 , and the film thickness was 16 ⁇ m.
- This polyolefin porous film was used as a separator 1 for a non-aqueous electrolyte secondary battery.
- the volume-based particle size distribution of the inorganic filler was calculated by measuring D10, D50 and D90 using a laser diffraction particle size distribution analyzer SALD2200 manufactured by Shimadzu Corporation.
- SALD2200 laser diffraction particle size distribution analyzer manufactured by Shimadzu Corporation.
- the particle diameter at which the cumulative distribution based on volume is 50%, the particle diameter at 10%, and the particle diameter at 90% are referred to as D50, D10, and D90, respectively.
- the specific surface area of the filler was calculated from the BET method by measuring the adsorption-desorption isotherm with nitrogen using the constant volume method.
- a vinylidene fluoride-hexafluoropropylene copolymer (manufactured by Arkema Ltd .; trade name “KYNAR2801”) was used.
- the inorganic filler, vinylidene fluoride-hexafluoropropylene copolymer and solvent were mixed in the following proportions. That is, after mixing 10 parts by weight of vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of inorganic filler, the solid content of the inorganic filler and vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid.
- a solvent was mixed so that the concentration of the above was 40% by weight to prepare a mixed solution.
- the obtained mixed liquid was stirred and mixed with a thin film swivel type high speed mixer (Filmiku (registered trademark) manufactured by Primix Co., Ltd.) to obtain a uniform coating liquid.
- the obtained coating liquid was applied to one side of the separator 1 for non-aqueous electrolyte secondary battery by a doctor blade method at a coating shear rate of 39.4 (1 / s), and the non-aqueous electrolysis was performed.
- a coating film was formed on one surface of the liquid secondary battery separator 1.
- the coating film was dried at 65 ° C. for 20 minutes to form the porous layer 1 on one surface of the separator 1 for non-aqueous electrolyte secondary battery.
- a laminate 1 including the separator 1 for non-aqueous electrolyte secondary battery and the porous layer 1 was obtained.
- the basis weight of the porous layer 1 was 7 g / m 2 and the thickness was 4 ⁇ m.
- the maximum values of the aspect ratio and peak intensity ratio (I (hkl) / I (abc) ) of the projected image of the inorganic filler on the surface of the porous layer were measured. The results are shown in Table 1.
- a commercially available positive electrode manufactured by applying LiNi 0.5 Mn 0.3 Co 0.2 O 2 / conductive agent / PVDF (weight ratio 92/5/3) to an aluminum foil was used.
- An aluminum foil was applied to the commercially available positive electrode so that the size of the part where the positive electrode active material layer was formed was 40 mm ⁇ 35 mm, and the part where the width of 13 mm was not formed and the positive electrode active material layer was not formed remained on the outer periphery thereof. It was cut out to obtain a positive electrode.
- the positive electrode active material layer had a thickness of 58 ⁇ m and a density of 2.50 g / cm 3 .
- a commercially available negative electrode manufactured by applying graphite / styrene-1,3-butadiene copolymer / sodium carboxymethyl cellulose (weight ratio 98/1/1) to a copper foil was used.
- a copper foil was applied to the commercially available negative electrode so that the size of the part where the negative electrode active material layer was formed was 50 mm ⁇ 40 mm, and the part where the width of 13 mm was not formed and the negative electrode active material layer was not formed remained on the outer periphery thereof. It was cut out to obtain a negative electrode.
- the negative electrode active material layer had a thickness of 49 ⁇ m and a density of 1.40 g / cm 3 .
- LiPF 6 was dissolved in a mixed solvent in which ethylene carbonate, ethylmethyl carbonate, and diethyl carbonate were mixed at a volume ratio of 3: 5: 2 so that the concentration thereof was 1 mol / L, to prepare an electrolytic solution stock solution 1.
- This electrolytic solution stock solution 1 is an aprotic polar solvent electrolytic solution containing Li + ions.
- Addition liquid 1 was prepared by adding diethyl carbonate to 10.3 mg of dibutylhydroxytoluene (BHT, ionic conductivity reduction rate: 5.3%) to make a volume of 5 mL.
- a non-aqueous electrolyte solution 1 was prepared by mixing 300 ⁇ L of the additive solution 1 and 1700 ⁇ L of the electrolyte solution stock solution 1.
- Table 2 shows the content of the additive in the non-aqueous electrolyte solution 1.
- a non-aqueous electrolyte secondary battery was manufactured by the following method using the positive electrode, the negative electrode, the laminate 1, and the non-aqueous electrolyte solution 1.
- the produced non-aqueous electrolyte secondary battery was designated as non-aqueous electrolyte secondary battery 1.
- a non-aqueous electrolyte secondary battery member 1 was obtained by stacking the positive electrode, the laminate 1 with the porous layer facing the positive electrode side, and the negative electrode in this order in a laminate pouch.
- the positive electrode and the negative electrode were arranged such that the entire main surface of the positive electrode active material layer of the positive electrode was included in the range of the main surface of the negative electrode active material layer of the negative electrode. That is, the positive electrode and the negative electrode were arranged such that the entire main surface of the positive electrode active material layer of the positive electrode overlaps the main surface of the negative electrode active material layer of the negative electrode.
- the non-aqueous electrolyte secondary battery member 1 was placed in a previously prepared bag in which an aluminum layer and a heat seal layer were laminated, and 0.23 mL of the non-aqueous electrolyte solution 1 was further placed in this bag. I put it in. Then, the inside of the bag was depressurized and the bag was heat-sealed to manufacture the non-aqueous electrolyte secondary battery 1.
- Example 2 [Preparation of non-aqueous electrolyte secondary battery] (Preparation of non-aqueous electrolyte) LiPF 6 was dissolved in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 3: 7 so that the concentration thereof was 1 mol / L, to prepare an electrolyte solution stock solution 2.
- Addition liquid 2 was prepared by adding diethyl carbonate to 10.0 mg of vinylene carbonate (VC, reduction rate of ionic conductivity: 1.3%) to make a volume of 5 mL. 200 ⁇ L of the additive solution 2 and 1800 ⁇ L of the electrolytic solution stock solution 2 were mixed, and 900 ⁇ L of the electrolytic solution stock solution 2 was added to 100 ⁇ L of the mixed solution of the additive solution 2 and the electrolytic solution stock solution 2 to give an additive solution 3.
- a non-aqueous electrolyte solution 2 was prepared by mixing 50 ⁇ L of the additive solution 3 and 1950 ⁇ L of the electrolyte solution stock solution 2. Table 2 shows the content of the additive in the non-aqueous electrolyte solution 2.
- a non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the non-aqueous electrolyte solution 2 was used instead of the non-aqueous electrolyte solution 1.
- the produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 2.
- Example 3 [Production of Laminated Body Comprising Non-Aqueous Electrolyte Secondary Battery Separator and Porous Layer]
- As the inorganic filler hexagonal plate-shaped zinc oxide having a mass percentage of oxygen atoms of 20% (manufactured by Sakai Chemical Industry Co., Ltd., trade name: XZ-100F) was used.
- a solid comprising the inorganic filler and the vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid after mixing 10 parts by weight of the vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of the inorganic filler.
- the mixture was prepared by mixing the solvents so that the concentration of the components was 37% by weight.
- the porous layer 2 was formed instead of the porous layer 1 by applying the coating liquid at a coating shear rate of 3.9 (1 / s).
- a non-aqueous electrolyte secondary was prepared in the same manner as in Example 1 except that the laminate 2 was used instead of the laminate 1 and the non-aqueous electrolyte 3 was used instead of the non-aqueous electrolyte 1.
- a battery was produced.
- the produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 3.
- Example 4 [Production of Laminated Body Comprising Nonaqueous Electrolyte Secondary Battery Separator and Porous Layer]
- a solid comprising the inorganic filler and the vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid after mixing 10 parts by weight of the vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of the inorganic filler.
- the mixture was prepared by mixing the solvents so that the concentration of the components was 30% by weight.
- the porous layer 3 was formed instead of the porous layer 1 by applying the coating liquid at a coating shear rate of 7.9 (1 / s).
- a non-aqueous electrolyte secondary battery was obtained in the same manner as in Example 1 except that the laminate 3 was used instead of the laminate 1 and the non-aqueous electrolyte 4 was used instead of the non-aqueous electrolyte 1.
- the produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 4.
- Example 5 [Production of Laminated Body Comprising Non-Aqueous Electrolyte Secondary Battery Separator and Porous Layer]
- a laminate 4 including the separator 1 for non-aqueous electrolyte secondary battery and the porous layer 4 was obtained in the same manner as in Example 1 except for the following.
- the inorganic filler Wollastonite (Hayashi Kasei Co., Ltd., trade name: Wollastonite VM-8N) having an oxygen atomic mass percentage of 41% was used.
- a solid comprising the inorganic filler and the vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid after mixing 10 parts by weight of the vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of the inorganic filler.
- the mixture was prepared by mixing the solvents so that the concentration of the components was 40% by weight.
- the porous layer 4 was formed instead of the porous layer 1 by applying the coating liquid at a coating shear rate of 7.9 (1 / s).
- LiPF 6 was dissolved in a mixed solvent prepared by mixing ethylene carbonate, ethylmethyl carbonate, and diethyl carbonate in a volume ratio of 2: 5: 3 so that the concentration of LiPF 6 was 1 mol / L to prepare an electrolytic solution stock solution 4. .. 90 ⁇ L of the additive solution 4 and 1910 ⁇ L of the electrolytic solution stock solution 4 were mixed to form a non-aqueous electrolytic solution 5.
- Table 2 shows the content of the additive in the non-aqueous electrolyte solution 5.
- Non-aqueous electrolyte secondary battery in the same manner as in Example 1 except that the laminate 4 was used instead of the laminate 1 and the non-aqueous electrolyte 5 was used instead of the non-aqueous electrolyte 1.
- the produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 5.
- a non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the non-aqueous electrolyte solution 6 was used instead of the non-aqueous electrolyte solution 1.
- the produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 6.
- Example 2 [Production of Laminated Body Comprising Non-Aqueous Electrolyte Secondary Battery Separator and Porous Layer]
- a laminate 5 including the separator 1 for non-aqueous electrolyte secondary battery and the porous layer 5 was obtained in the same manner as in Example 1 except for the following.
- Non-aqueous electrolyte secondary battery (Assembly of non-aqueous electrolyte secondary battery)
- Example 3 [Production of Laminated Body Comprising Non-Aqueous Electrolyte Secondary Battery Separator and Porous Layer]
- a laminate 6 including the separator 1 for non-aqueous electrolyte secondary battery and the porous layer 6 was obtained in the same manner as in Example 1 except for the following.
- As the inorganic filler hexagonal plate-shaped zinc oxide having a mass percentage of oxygen atoms of 20% (manufactured by Sakai Chemical Industry Co., Ltd., trade name: XZ-100F) was used.
- a solid comprising the inorganic filler and the vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid after mixing 10 parts by weight of the vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of the inorganic filler.
- the mixture was prepared by mixing the solvents so that the concentration of the components was 37% by weight.
- the porous layer 6 was formed instead of the porous layer 1 by applying the coating liquid at a coating shear rate of 0.4 (1 / s).
- Nonaqueous electrolyte secondary battery (Assembly of non-aqueous electrolyte secondary battery)
- the produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 8.
- Example 4 [Production of Laminated Body Comprising Non-Aqueous Electrolyte Secondary Battery Separator and Porous Layer]
- a laminate 7 including the non-aqueous electrolyte secondary battery separator 1 and the porous layer 7 was obtained in the same manner as in Example 1 except for the following.
- As the inorganic filler attapulgite (Hayashi Kasei Co., Ltd., trade name: ATTAGEL # 50) having an oxygen atomic mass percentage of 48% was used.
- a solid comprising the inorganic filler and the vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid after mixing 10 parts by weight of the vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of the inorganic filler.
- the mixture was prepared by mixing the solvents so that the concentration of the components became 17% by weight.
- a non-aqueous electrolyte secondary battery separator is coated with a coating solution at a coating shear rate of 1.3 (1 / s) on one side by a doctor blade method, so that it is porous instead of the porous layer 1.
- Non-aqueous electrolyte secondary battery (Assembly of non-aqueous electrolyte secondary battery)
- Non-aqueous electrolyte secondary battery in the same manner as in Example 1 except that the laminate 7 was used in place of the laminate 1 and the non-aqueous electrolyte 4 was used in place of the non-aqueous electrolyte 1.
- the produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 9.
- Example 5 [Production of Laminated Body Comprising Non-Aqueous Electrolyte Secondary Battery Separator and Porous Layer]
- a laminate 8 including the separator 1 for a non-aqueous electrolyte secondary battery and the porous layer 8 was obtained in the same manner as in Example 1 except for the following.
- -Mica manufactured by Wako Pure Chemical Industries, trade name: non-swelling mica
- oxygen atomic mass percentage of 44% was used as the inorganic filler.
- a solid comprising the inorganic filler and the vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid after mixing 10 parts by weight of the vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of the inorganic filler.
- a mixed solution was prepared by mixing the solvents so that the concentration of the components was 20% by weight.
- a porous layer instead of the porous layer 1 is formed by applying the coating solution on one surface of the separator for a non-aqueous electrolyte secondary battery by a doctor blade method at a coating shear rate of 0.4 (1 / s). Formed 8.
- Non-aqueous electrolyte secondary battery (Assembly of non-aqueous electrolyte secondary battery)
- Non-aqueous electrolyte secondary battery was manufactured in the same manner as in Example 1 except that the laminate 8 was used instead of the laminate 1 and the non-aqueous electrolyte 4 was used instead of the non-aqueous electrolyte 1.
- the produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 10.
- Example 6 [Preparation of non-aqueous electrolyte secondary battery] (Assembly of non-aqueous electrolyte secondary battery) A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the electrolyte solution 1 was used instead of the non-aqueous electrolyte solution 1. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 11.
- a non-aqueous electrolyte secondary battery according to an embodiment of the present invention that satisfies the requirements and (iii) the requirements regarding the ionic conductivity reduction rate and the content of the additive contained in the non-aqueous electrolyte is a high-rate discharge ( It was shown that the 1C charge capacity after 3C discharge) was excellent.
- the non-aqueous electrolyte secondary battery according to an embodiment of the present invention is excellent in charge capacity after high-rate discharge, and thus is suitably used as a battery used in personal computers, mobile phones, personal digital assistants, and the like, and as a vehicle battery. can do.
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Abstract
The purpose of the present invention is to achieve a non-aqueous electrolyte secondary battery having excellent charging capacity following high-rate discharge. The non-aqueous electrolyte secondary battery according to the present invention comprises: a porous layer for which the aspect ratio of a projected image of an inorganic filler at the surface of said secondary battery is in the range of 1.4-4.0 and the maximum value of a peak intensity ratio: I(hkl)/I(abc) is in the range of 1.5-300; a positive electrode; a negative electrode; and a non-aqueous electrolyte which contains 0.5-300 ppm of a specified additive.
Description
本発明は、非水電解液二次電池に関する。
The present invention relates to a non-aqueous electrolyte secondary battery.
非水電解液二次電池、特にリチウムイオン二次電池は、エネルギー密度が高いのでパーソナルコンピュータ、携帯電話、携帯情報端末などに用いる電池として広く使用され、また最近では車載用の電池として開発が進められている。
Non-aqueous electrolyte secondary batteries, especially lithium-ion secondary batteries, are widely used as batteries for personal computers, mobile phones, personal digital assistants, etc. because of their high energy density, and recently they have been developed as in-vehicle batteries. Has been.
非水電解液二次電池として、例えば、特許文献1に記載されたような板状の無機フィラーを含有し、空孔率が60~90%である多孔質層を多孔質基材の少なくとも一面に積層させた非水系二次電池用セパレータを備える非水電解液二次電池が知られている。
As a non-aqueous electrolyte secondary battery, for example, a porous layer containing a plate-like inorganic filler as described in Patent Document 1 and having a porosity of 60 to 90% is provided on at least one surface of a porous substrate. There is known a non-aqueous electrolyte secondary battery including a non-aqueous secondary battery separator that is laminated on.
しかしながら、上述のような従来技術は、ハイレート放電後の充電容量の観点からは改善の余地があった。
However, the above-mentioned conventional technology has room for improvement in terms of charge capacity after high-rate discharge.
本発明は、前記の問題点に鑑みてなされたものであり、その目的は、ハイレート放電後の充電容量に優れた非水電解液二次電池を実現することにある。
The present invention has been made in view of the above problems, and an object thereof is to realize a non-aqueous electrolyte secondary battery having an excellent charge capacity after high rate discharge.
本発明の態様1に係る非水電解液二次電池は、無機フィラーと樹脂とを含む多孔質層、非水電解液、正極および負極を備え、
前記多孔質層の表面の、無機フィラーの投影像のアスペクト比が、1.4~4.0の範囲であり、
前記多孔質層の、広角X線回折法により測定した、互いに直交する任意の回折面(hkl)、(abc)のピーク強度:I(hkl)およびI(abc)が下式(1)を満たし、
下式(2)で算出されるピーク強度比の最大値の範囲が、1.5~300の範囲であり、
I(hkl) > I(abc)・・・(1)、
I(hkl) / I(abc)・・・(2)
前記非水電解液は、下記式(A)で表されるイオン電導度低下率Lが1.0%以上、6.0%以下である添加剤を0.5ppm以上、300ppm以下含有する。 A non-aqueous electrolyte secondary battery according to Aspect 1 of the present invention includes a porous layer containing an inorganic filler and a resin, a non-aqueous electrolyte, a positive electrode and a negative electrode,
The aspect ratio of the projected image of the inorganic filler on the surface of the porous layer is in the range of 1.4 to 4.0,
Peak strengths of arbitrary diffraction planes (hkl) and (abc) orthogonal to each other, measured by a wide-angle X-ray diffraction method, of the porous layer: I (hkl) and I (abc) satisfy the following formula (1). ,
The range of the maximum value of the peak intensity ratio calculated by the following equation (2) is in the range of 1.5 to 300,
I (hkl) > I (abc) ... (1),
I (hkl) / I (abc)・ ・ ・ (2)
The non-aqueous electrolyte contains 0.5 ppm or more and 300 ppm or less of an additive having an ionic conductivity reduction rate L represented by the following formula (A) of 1.0% or more and 6.0% or less.
前記多孔質層の表面の、無機フィラーの投影像のアスペクト比が、1.4~4.0の範囲であり、
前記多孔質層の、広角X線回折法により測定した、互いに直交する任意の回折面(hkl)、(abc)のピーク強度:I(hkl)およびI(abc)が下式(1)を満たし、
下式(2)で算出されるピーク強度比の最大値の範囲が、1.5~300の範囲であり、
I(hkl) > I(abc)・・・(1)、
I(hkl) / I(abc)・・・(2)
前記非水電解液は、下記式(A)で表されるイオン電導度低下率Lが1.0%以上、6.0%以下である添加剤を0.5ppm以上、300ppm以下含有する。 A non-aqueous electrolyte secondary battery according to Aspect 1 of the present invention includes a porous layer containing an inorganic filler and a resin, a non-aqueous electrolyte, a positive electrode and a negative electrode,
The aspect ratio of the projected image of the inorganic filler on the surface of the porous layer is in the range of 1.4 to 4.0,
Peak strengths of arbitrary diffraction planes (hkl) and (abc) orthogonal to each other, measured by a wide-angle X-ray diffraction method, of the porous layer: I (hkl) and I (abc) satisfy the following formula (1). ,
The range of the maximum value of the peak intensity ratio calculated by the following equation (2) is in the range of 1.5 to 300,
I (hkl) > I (abc) ... (1),
I (hkl) / I (abc)・ ・ ・ (2)
The non-aqueous electrolyte contains 0.5 ppm or more and 300 ppm or less of an additive having an ionic conductivity reduction rate L represented by the following formula (A) of 1.0% or more and 6.0% or less.
L=(LA-LB)/LA・・・(A)
(式(A)中、LAは、エチレンカーボネート、エチルメチルカーボネートおよびジエチルカーボネートを3:5:2の体積比で含む混合溶媒に、LiPF6をその濃度が1mol/Lとなるように溶解させた参照用電解液のイオン電導度(mS/cm)を表し、LBは、前記参照用電解液に、添加剤を1.0重量%溶解させた電解液のイオン電導度(mS/cm)を表す。)
また、本発明の態様2に係る非水電解液二次電池は、前記態様1において、前記多孔質層が、ポリオレフィン多孔質フィルムの片面または両面に積層されている。 L = (LA-LB) / LA ... (A)
(In the formula (A), LA was prepared by dissolving LiPF 6 in a mixed solvent containing ethylene carbonate, ethylmethyl carbonate and diethyl carbonate in a volume ratio of 3: 5: 2 such that the concentration thereof was 1 mol / L. The ionic conductivity (mS / cm) of the reference electrolytic solution is represented, and LB represents the ionic conductivity (mS / cm) of the electrolytic solution prepared by dissolving the additive in the reference electrolytic solution in an amount of 1.0% by weight. .)
Further, the non-aqueous electrolyte secondary battery according to Aspect 2 of the present invention is the same as in Aspect 1, except that the porous layer is laminated on one side or both sides of the polyolefin porous film.
(式(A)中、LAは、エチレンカーボネート、エチルメチルカーボネートおよびジエチルカーボネートを3:5:2の体積比で含む混合溶媒に、LiPF6をその濃度が1mol/Lとなるように溶解させた参照用電解液のイオン電導度(mS/cm)を表し、LBは、前記参照用電解液に、添加剤を1.0重量%溶解させた電解液のイオン電導度(mS/cm)を表す。)
また、本発明の態様2に係る非水電解液二次電池は、前記態様1において、前記多孔質層が、ポリオレフィン多孔質フィルムの片面または両面に積層されている。 L = (LA-LB) / LA ... (A)
(In the formula (A), LA was prepared by dissolving LiPF 6 in a mixed solvent containing ethylene carbonate, ethylmethyl carbonate and diethyl carbonate in a volume ratio of 3: 5: 2 such that the concentration thereof was 1 mol / L. The ionic conductivity (mS / cm) of the reference electrolytic solution is represented, and LB represents the ionic conductivity (mS / cm) of the electrolytic solution prepared by dissolving the additive in the reference electrolytic solution in an amount of 1.0% by weight. .)
Further, the non-aqueous electrolyte secondary battery according to Aspect 2 of the present invention is the same as in Aspect 1, except that the porous layer is laminated on one side or both sides of the polyolefin porous film.
また、本発明の態様3に係る非水電解液二次電池は、前記態様1または2において、前記多孔質層が、ポリオレフィン、(メタ)アクリレート系樹脂、含フッ素樹脂、ポリアミド系樹脂、ポリエステル系樹脂および水溶性ポリマーからなる群より1種以上選択される樹脂を含む。
Further, in the non-aqueous electrolyte secondary battery according to Aspect 3 of the present invention, in the Aspect 1 or 2, the porous layer has a polyolefin, a (meth) acrylate resin, a fluorine-containing resin, a polyamide resin, a polyester resin. It includes a resin selected from the group consisting of resins and water-soluble polymers.
また、本発明の態様4に係る非水電解液二次電池は、前記態様3において、上記ポリアミド系樹脂がアラミド樹脂である。
Further, in the non-aqueous electrolyte secondary battery according to Aspect 4 of the present invention, in the Aspect 3, the polyamide resin is an aramid resin.
また、本発明の態様5に係る非水電解液二次電池は、前記態様1~4のいずれか1つにおいて、前記非水電解液が、リチウムを含有している電解質を含む。
The nonaqueous electrolyte secondary battery according to Aspect 5 of the present invention is the nonaqueous electrolyte secondary battery according to any one of Aspects 1 to 4, wherein the nonaqueous electrolyte solution contains an electrolyte containing lithium.
また、本発明の態様6に係る非水電解液二次電池は、前記態様1~5のいずれか1つにおいて、前記非水電解液が、非プロトン性極性溶媒を含む。
Further, in the non-aqueous electrolyte secondary battery according to Aspect 6 of the present invention, in any one of Aspects 1 to 5, the non-aqueous electrolyte contains an aprotic polar solvent.
本発明の一態様によれば、ハイレート放電(例えば、3Cの放電)後の1C充電容量に優れた非水電解液二次電池を実現できる。
According to one aspect of the present invention, it is possible to realize a non-aqueous electrolyte secondary battery having an excellent 1C charge capacity after high rate discharge (for example, 3C discharge).
本発明の一実施形態に関して以下に説明するが、本発明はこれに限定されるものではない。本発明は、以下に説明する各構成に限定されるものではなく、特許請求の範囲に示した範囲で種々の変更が可能であり、異なる実施形態にそれぞれ開示された技術的手段を適宜組み合わせて得られる実施形態に関しても本発明の技術的範囲に含まれる。なお、本明細書において特記しない限り、数値範囲を表す「A~B」は、「A以上、B以下」を意味する。
An embodiment of the present invention will be described below, but the present invention is not limited to this. The present invention is not limited to each configuration described below, various modifications are possible within the scope shown in the claims, and the technical means disclosed in different embodiments are appropriately combined. The obtained embodiments are also included in the technical scope of the present invention. Unless otherwise specified in the present specification, “A to B” representing a numerical range means “A or more and B or less”.
本発明の一実施形態に係る非水電解液二次電池は、後述する多孔質層、後述する正極、後述する負極および後述する非水電解液を備える。また、本発明の一実施形態に係る非水電解液二次電池は、後述するポリオレフィン多孔質フィルムをさらに備え得る。
A non-aqueous electrolyte secondary battery according to an embodiment of the present invention includes a porous layer described below, a positive electrode described below, a negative electrode described below, and a non-aqueous electrolytic solution described below. The non-aqueous electrolyte secondary battery according to the exemplary embodiment of the present invention may further include a polyolefin porous film described below.
本発明の一実施形態に係る非水電解液二次電池を構成する部材について以下に詳述する。
The members constituting the non-aqueous electrolyte secondary battery according to the embodiment of the present invention will be described in detail below.
[多孔質層]
本発明の一実施形態における多孔質層は、無機フィラーと樹脂とを含む多孔質層であって、当該多孔質層の表面の無機フィラーの投影像のアスペクト比が、1.4~4.0の範囲であり、前記多孔質層の、広角X線回折法により測定した、互いに直交する任意の回折面(hkl)、(abc)のピーク強度:I(hkl)およびI(abc)が下式(1)を満たし、下式(2)で算出されるピーク強度比の最大値の範囲が、1.5~300の範囲である事を特徴とする。なお、以下では前記多孔質層の表面を「多孔質層表面」と称する場合がある。
I(hkl) > I(abc) ・・・(1)、
I(hkl) / I(abc) ・・・(2)。 [Porous layer]
The porous layer in one embodiment of the present invention is a porous layer containing an inorganic filler and a resin, and the aspect ratio of the projected image of the inorganic filler on the surface of the porous layer is 1.4 to 4.0. And the peak intensities of arbitrary diffraction planes (hkl) and (abc) of the porous layer, which are orthogonal to each other, measured by a wide-angle X-ray diffraction method: I (hkl) and I (abc) are expressed by the following formula: It is characterized in that the range of the maximum value of the peak intensity ratio, which satisfies the condition (1) and is calculated by the following formula (2), is in the range of 1.5 to 300. In addition, below, the surface of the said porous layer may be called a "porous layer surface."
I (hkl) > I (abc) ... (1),
I (hkl) / I (abc) (2).
本発明の一実施形態における多孔質層は、無機フィラーと樹脂とを含む多孔質層であって、当該多孔質層の表面の無機フィラーの投影像のアスペクト比が、1.4~4.0の範囲であり、前記多孔質層の、広角X線回折法により測定した、互いに直交する任意の回折面(hkl)、(abc)のピーク強度:I(hkl)およびI(abc)が下式(1)を満たし、下式(2)で算出されるピーク強度比の最大値の範囲が、1.5~300の範囲である事を特徴とする。なお、以下では前記多孔質層の表面を「多孔質層表面」と称する場合がある。
I(hkl) > I(abc) ・・・(1)、
I(hkl) / I(abc) ・・・(2)。 [Porous layer]
The porous layer in one embodiment of the present invention is a porous layer containing an inorganic filler and a resin, and the aspect ratio of the projected image of the inorganic filler on the surface of the porous layer is 1.4 to 4.0. And the peak intensities of arbitrary diffraction planes (hkl) and (abc) of the porous layer, which are orthogonal to each other, measured by a wide-angle X-ray diffraction method: I (hkl) and I (abc) are expressed by the following formula: It is characterized in that the range of the maximum value of the peak intensity ratio, which satisfies the condition (1) and is calculated by the following formula (2), is in the range of 1.5 to 300. In addition, below, the surface of the said porous layer may be called a "porous layer surface."
I (hkl) > I (abc) ... (1),
I (hkl) / I (abc) (2).
本発明の一実施形態において、多孔質層は、非水電解液二次電池を構成する部材として、ポリオレフィン多孔質フィルムと、正極および負極の少なくともいずれか一方との間に配置され得る。前記多孔質層は、ポリオレフィン多孔質フィルムの片面または両面に形成され得る。或いは、前記多孔質層は、正極および負極の少なくともいずれか一方の活物質層上に形成され得る。或いは、前記多孔質層は、ポリオレフィン多孔質フィルムと、正極および負極の少なくともいずれか一方との間に、これらと接するように配置されてもよい。ポリオレフィン多孔質フィルムと正極および負極の少なくともいずれか一方との間に配置される多孔質層は1層でもよく2層以上であってもよい。多孔質層は、樹脂を含む絶縁性の多孔質層であることが好ましい。
In one embodiment of the present invention, the porous layer may be disposed between the polyolefin porous film and at least one of the positive electrode and the negative electrode as a member constituting the non-aqueous electrolyte secondary battery. The porous layer may be formed on one side or both sides of the polyolefin porous film. Alternatively, the porous layer may be formed on the active material layer of at least one of the positive electrode and the negative electrode. Alternatively, the porous layer may be arranged between the polyolefin porous film and at least one of the positive electrode and the negative electrode so as to be in contact with them. The porous layer arranged between the polyolefin porous film and at least one of the positive electrode and the negative electrode may be one layer or two or more layers. The porous layer is preferably an insulating porous layer containing a resin.
ポリオレフィン多孔質フィルムの片面に多孔質層が積層される場合には、当該多孔質層は、好ましくは、ポリオレフィン多孔質フィルムにおける正極と対向する面に積層される。より好ましくは、当該多孔質層は、正極と接する面に積層される。
When the porous layer is laminated on one side of the polyolefin porous film, the porous layer is preferably laminated on the surface of the polyolefin porous film facing the positive electrode. More preferably, the porous layer is laminated on the surface in contact with the positive electrode.
上述の「多孔質層の表面の無機フィラーの投影像のアスペクト比」および上述の「式(2)で算出されるピーク強度比の最大値」は、共に、多孔質層における無機フィラーの配向性を表す指標である。ここで、前記配向性が高い場合と、前記配向性が低い場合の、多孔質層における無機フィラーの様態の模式図を図1に示す。図1の左図が、無機フィラーを含む多孔質層における、フィラーの配向性が大きく異方性が高い場合の当該多孔質層の構造を表す模式図であり、図1の右図が、無機フィラーの配向性が小さく異方性が低い場合の当該多孔質層の構造を表す模式図である。
The above-mentioned “aspect ratio of the projected image of the inorganic filler on the surface of the porous layer” and the above-mentioned “maximum value of the peak intensity ratio calculated by the formula (2)” are both the orientation of the inorganic filler in the porous layer. Is an index representing. Here, FIG. 1 shows a schematic diagram of the state of the inorganic filler in the porous layer when the orientation is high and when the orientation is low. The left diagram of FIG. 1 is a schematic diagram showing the structure of the porous layer containing an inorganic filler when the orientation of the filler is large and the anisotropy is high, and the right diagram of FIG. 1 is the inorganic layer. It is a schematic diagram showing the structure of the said porous layer in case the orientation of a filler is small and anisotropy is low.
本発明の一実施形態における多孔質層は、無機フィラーと、樹脂とを含む。多孔質層は、内部に多数の細孔を有し、これら細孔が連結された構造となっており、一方の面から他方の面へと気体或いは液体が通過可能となった層である。また、本発明の一実施形態における多孔質層が後述する非水電解液二次電池用積層セパレータを構成する部材として使用される場合、前記多孔質層は、当該積層セパレータの最外層として、電極と接する層となり得る。
The porous layer in one embodiment of the present invention contains an inorganic filler and a resin. The porous layer has a large number of pores inside and has a structure in which these pores are connected, and is a layer through which gas or liquid can pass from one surface to the other surface. Further, when the porous layer in one embodiment of the present invention is used as a member constituting a non-aqueous electrolyte secondary battery laminated separator described below, the porous layer is an electrode as an outermost layer of the laminated separator. Can be a layer in contact with.
本発明の一実施形態における多孔質層に含まれる樹脂は、電池の電解液に不溶であり、また、その電池の使用範囲において電気化学的に安定であることが好ましい。前記樹脂としては、具体的には、例えば、ポリオレフィン;(メタ)アクリレート系樹脂;含フッ素樹脂;ポリアミド系樹脂;ポリイミド系樹脂;ポリエステル系樹脂;ゴム類;融点またはガラス転移温度が180℃以上の樹脂;水溶性ポリマー;ポリカーボネート、ポリアセタール、ポリエーテルエーテルケトン等が挙げられる。
The resin contained in the porous layer in one embodiment of the present invention is preferably insoluble in the electrolytic solution of the battery and is electrochemically stable in the usage range of the battery. Specific examples of the resin include polyolefins; (meth) acrylate resins; fluorine-containing resins; polyamide resins; polyimide resins; polyester resins; rubbers; melting points or glass transition temperatures of 180 ° C. or higher. Resins; water-soluble polymers; polycarbonates, polyacetals, polyether ether ketones and the like.
上述の樹脂のうち、ポリオレフィン、ポリエステル系樹脂、(メタ)アクリレート系樹脂、含フッ素樹脂、ポリアミド系樹脂および水溶性ポリマーが好ましい。
Among the above resins, polyolefins, polyester resins, (meth) acrylate resins, fluorine-containing resins, polyamide resins and water-soluble polymers are preferable.
ポリオレフィンとしては、ポリエチレン、ポリプロピレン、ポリブテン、およびエチレン-プロピレン共重合体等が好ましい。
As the polyolefin, polyethylene, polypropylene, polybutene, ethylene-propylene copolymer and the like are preferable.
ポリアミド系樹脂としては、芳香族ポリアミドおよび全芳香族ポリアミドなどのアラミド樹脂が好ましい。
As the polyamide resin, aramid resins such as aromatic polyamide and wholly aromatic polyamide are preferable.
アラミド樹脂としては、具体的には、例えば、ポリ(パラフェニレンテレフタルアミド)、ポリ(メタフェニレンイソフタルアミド)、ポリ(パラベンズアミド)、ポリ(メタベンズアミド)、ポリ(4,4’-ベンズアニリドテレフタルアミド)、ポリ(パラフェニレン-4,4’-ビフェニレンジカルボン酸アミド)、ポリ(メタフェニレン-4,4’-ビフェニレンジカルボン酸アミド)、ポリ(パラフェニレン-2,6-ナフタレンジカルボン酸アミド)、ポリ(メタフェニレン-2,6-ナフタレンジカルボン酸アミド)、ポリ(2-クロロパラフェニレンテレフタルアミド)、パラフェニレンテレフタルアミド/2,6-ジクロロパラフェニレンテレフタルアミド共重合体、メタフェニレンテレフタルアミド/2,6-ジクロロパラフェニレンテレフタルアミド共重合体等が挙げられる。このうち、ポリ(パラフェニレンテレフタルアミド)がより好ましい。
Specific examples of the aramid resin include poly (paraphenylene terephthalamide), poly (metaphenylene isophthalamide), poly (parabenzamide), poly (metabenzamide), poly (4,4′-benzanilide terephthalate). Amide), poly (paraphenylene-4,4′-biphenylenedicarboxylic acid amide), poly (metaphenylene-4,4′-biphenylenedicarboxylic acid amide), poly (paraphenylene-2,6-naphthalenedicarboxylic acid amide), Poly (metaphenylene-2,6-naphthalenedicarboxylic acid amide), poly (2-chloroparaphenylene terephthalamide), paraphenylene terephthalamide / 2,6-dichloroparaphenylene terephthalamide copolymer, metaphenylene terephthalamide / 2 , 6-diclosure Paraphenylene terephthalamide copolymer and the like. Of these, poly (paraphenylene terephthalamide) is more preferable.
ポリエステル系樹脂としては、ポリアリレートなどの芳香族ポリエステルおよび液晶ポリエステルが好ましい。
As the polyester resin, aromatic polyester such as polyarylate and liquid crystal polyester are preferable.
ゴム類としては、スチレン-ブタジエン共重合体およびその水素化物、メタクリル酸エステル共重合体、アクリロニトリル-アクリル酸エステル共重合体、スチレン-アクリル酸エステル共重合体、エチレンプロピレンラバー、ポリ酢酸ビニル等を挙げることができる。
Examples of rubbers include styrene-butadiene copolymer and its hydride, methacrylic acid ester copolymer, acrylonitrile-acrylic acid ester copolymer, styrene-acrylic acid ester copolymer, ethylene propylene rubber, polyvinyl acetate and the like. Can be mentioned.
融点又はガラス転移温度が180℃以上の樹脂としては、ポリフェニレンエーテル、ポリスルホン、ポリエーテルスルホン、ポリフェニレンスルフィド、ポリエーテルイミド、ポリアミドイミド、ポリエーテルアミド等を挙げることができる。
Examples of the resin having a melting point or glass transition temperature of 180 ° C. or higher include polyphenylene ether, polysulfone, polyether sulfone, polyphenylene sulfide, polyetherimide, polyamideimide, and polyetheramide.
水溶性ポリマーとしては、ポリビニルアルコール、ポリエチレングリコール、セルロースエーテル、アルギン酸ナトリウム、ポリアクリル酸、ポリアクリルアミド、ポリメタクリル酸等を挙げることができる。
Examples of water-soluble polymers include polyvinyl alcohol, polyethylene glycol, cellulose ether, sodium alginate, polyacrylic acid, polyacrylamide, polymethacrylic acid and the like.
含フッ素樹脂としては、ポリフッ化ビニリデン(PVDF)、ポリテトラフルオロエチレン、フッ化ビニリデン-ヘキサフルオロプロピレン共重合体、テトラフルオロエチレン-ヘキサフルオロプロピレン共重合体、テトラフルオロエチレン-パーフルオロアルキルビニルエーテル共重合体、フッ化ビニリデン-テトラフルオロエチレン共重合体、フッ化ビニリデン-トリフルオロエチレン共重合体、フッ化ビニリデン-トリクロロエチレン共重合体、フッ化ビニリデン-フッ化ビニル共重合体、フッ化ビニリデン-ヘキサフルオロプロピレン-テトラフルオロエチレン共重合体、およびエチレン-テトラフルオロエチレン共重合体等、並びに、前記含フッ素樹脂の中でもガラス転移温度が23℃以下である含フッ素ゴムを挙げることができる。
Examples of the fluorine-containing resin include polyvinylidene fluoride (PVDF), polytetrafluoroethylene, vinylidene fluoride-hexafluoropropylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer Coalescence, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-trichloroethylene copolymer, vinylidene fluoride-vinyl fluoride copolymer, vinylidene fluoride-hexafluoro Among them, propylene-tetrafluoroethylene copolymer, ethylene-tetrafluoroethylene copolymer and the like, and fluorine-containing rubber having a glass transition temperature of 23 ° C. or lower among the above-mentioned fluorine-containing resins can be mentioned. That.
なお、本発明の一実施形態における多孔質層に含まれる樹脂は、1種類でもよく、2種類以上の樹脂の混合物でもよい。
The resin contained in the porous layer in the embodiment of the present invention may be one kind or a mixture of two or more kinds.
前記樹脂の中でも、多孔質層が正極に対向して配置される場合には、電池作動時に酸化劣化が生じたとしても、非水電解液二次電池のレート特性および抵抗特性等の各種性能を維持し易いため、含フッ素樹脂が好ましい。
Among the resins, when the porous layer is arranged facing the positive electrode, various performances such as rate characteristics and resistance characteristics of the non-aqueous electrolyte secondary battery can be obtained even if oxidative deterioration occurs during battery operation. A fluorine-containing resin is preferable because it can be easily maintained.
本発明の一実施形態における多孔質層は、無機フィラーを含む。その含有量の下限値は、前記フィラーと、本発明の一実施形態における多孔質層を構成する樹脂との総重量に対して、50重量%以上であることが好ましく、70重量%以上であることがより好ましく、90重量%以上であることがさらに好ましい。一方、本発明の一実施形態における多孔質層における、無機フィラーの含有量の上限値は、99重量%以下であることが好ましく、98重量%以下であることがより好ましい。前記フィラーの含有量が、50重量%以上であることが耐熱性の観点から好ましく、前記フィラーの含有量が、99重量%以下であることがフィラー間の密着性の観点から好ましい。無機フィラーを含有することで、前記多孔質層を含むセパレータの滑り性および耐熱性を向上し得る。無機フィラーとしては、非水電解液に安定であり、かつ、電気化学的に安定なフィラーであれば特に限定されない。電池の安全性を確保する観点からは、耐熱温度が150℃以上のフィラーが好ましい。
The porous layer in one embodiment of the present invention contains an inorganic filler. The lower limit of the content is preferably 50% by weight or more and 70% by weight or more based on the total weight of the filler and the resin constituting the porous layer in the embodiment of the present invention. More preferably, it is more preferably 90% by weight or more. On the other hand, the upper limit of the content of the inorganic filler in the porous layer in the embodiment of the present invention is preferably 99% by weight or less, and more preferably 98% by weight or less. The content of the filler is preferably 50% by weight or more from the viewpoint of heat resistance, and the content of the filler is preferably 99% by weight or less from the viewpoint of adhesion between the fillers. By containing the inorganic filler, the slipperiness and heat resistance of the separator including the porous layer can be improved. The inorganic filler is not particularly limited as long as it is a filler that is stable in a non-aqueous electrolytic solution and is electrochemically stable. From the viewpoint of ensuring the safety of the battery, a filler having a heat resistant temperature of 150 ° C. or higher is preferable.
前記無機フィラーは、特に限定されないが、通常、絶縁性フィラーである。前記無機フィラーは、好ましくは、アルミニウム元素、亜鉛元素、カルシウム元素、ジルコニア元素、ケイ素元素、マグネシウム元素、バリウム元素、およびホウ素元素からなる群から選ばれる少なくとも1種の金属元素を含む無機物であり、好ましくはアルミニウム元素を含む無機物である。また、無機フィラーは、好ましくは前記金属元素の酸化物を含む。
The inorganic filler is not particularly limited, but is usually an insulating filler. The inorganic filler is preferably an inorganic material containing at least one metal element selected from the group consisting of aluminum element, zinc element, calcium element, zirconia element, silicon element, magnesium element, barium element, and boron element, It is preferably an inorganic substance containing an aluminum element. Further, the inorganic filler preferably contains an oxide of the metal element.
具体的には、無機フィラーとして、チタン酸化物、アルミナ(Al2O3)、酸化亜鉛(ZnO)、酸化カルシウム(CaO)、酸化ジルコニア(ZrO2)、シリカ、マグネシア、酸化バリウム、酸化ホウ素、マイカ、ワラストナイト、アタパルジャイト、ベーマイト(アルミナ1水和物)などを挙げることができる。前記無機フィラーとしては、1種類のフィラーを単独で使用してもよく、2種類以上のフィラーを組み合わせて使用してもよい。
Specifically, as the inorganic filler, titanium oxide, alumina (Al 2 O 3 ), zinc oxide (ZnO), calcium oxide (CaO), zirconia oxide (ZrO 2 ), silica, magnesia, barium oxide, boron oxide, Examples thereof include mica, wollastonite, attapulgite, and boehmite (alumina monohydrate). As the inorganic filler, one kind of filler may be used alone, or two or more kinds of filler may be used in combination.
本発明の一実施形態における多孔質層における無機フィラーは、アルミナおよび板状フィラーを含むことが好ましい。前記板状フィラーとしては、上で挙げた金属元素の酸化物のうち、例えば、酸化亜鉛(ZnO)、マイカおよびベーマイトからなる群より選ばれる1以上のフィラーを挙げることができる。
The inorganic filler in the porous layer in one embodiment of the present invention preferably contains alumina and a plate-like filler. Examples of the plate-like filler include one or more fillers selected from the group consisting of zinc oxide (ZnO), mica, and boehmite among the oxides of the metal elements listed above.
前記無機フィラーの体積平均粒子径は、良好な接着性と滑り性の確保、および積層体の成形性の観点から、0.01μm~10μmの範囲であることが好ましい。その下限値としては0.05μm以上がより好ましく、0.1μm以上がさらに好ましい。その上限値としては5μm以下がより好ましく、1μm以下がさらに好ましい。
The volume average particle size of the inorganic filler is preferably in the range of 0.01 μm to 10 μm from the viewpoint of ensuring good adhesiveness and slipperiness, and moldability of the laminate. The lower limit value is more preferably 0.05 μm or more, further preferably 0.1 μm or more. The upper limit value is more preferably 5 μm or less, further preferably 1 μm or less.
前記無機フィラーの形状は、任意であり、特に限定されない。前記無機フィラーの形状は、粒子状であり得、例えば、球形状;楕円形状;板状;棒状;不定形状;繊維状;ピーナッツ状および/またはテトラポット状のように球状または柱状の単一粒子が熱融着した形状;の何れでもよい。電池の短絡防止の観点から、前記無機フィラーは、板状の粒子、および/または、凝集していない一次粒子であることが好ましい。また、イオン透過の観点からは、前記無機フィラーの形状は、多孔質中の粒子が最密充填され難く、粒子間に空隙が形成され易い、瘤、へこみ、くびれ、隆起もしくは膨らみを有する、樹枝状、珊瑚状、もしくは房(ふさ)状などの不定形状;繊維状;ピーナッツ状および/またはテトラポット状のように単一粒子が熱融着した形状であることが好ましい。前記無機フィラーの形状は、ピーナッツ状および/またはテトラポット状のように球状または柱状の単一粒子が熱融着した形状であることが特に好ましい。
The shape of the inorganic filler is arbitrary and is not particularly limited. The shape of the inorganic filler may be a particle shape, for example, a spherical shape; an elliptical shape; a plate shape; a rod shape; an indefinite shape; a fibrous shape; a spherical or columnar single particle such as a peanut shape and / or a tetrapot shape. The shape may be any of the above. From the viewpoint of preventing a short circuit in the battery, the inorganic filler is preferably plate-like particles and / or non-aggregated primary particles. Further, from the viewpoint of ion permeation, the shape of the inorganic filler is such that the particles in the porous material are difficult to be most closely packed, voids are easily formed between the particles, bumps, dents, constrictions, ridges or bulges, and dendritic It is preferable that a single particle is heat-fused such as an indeterminate shape such as a shape, a coral shape, or a tuft shape; a fibrous shape; a peanut shape and / or a tetrapot shape. The shape of the inorganic filler is particularly preferably a shape in which spherical or columnar single particles such as peanut-shaped and / or tetrapot-shaped particles are heat-sealed.
フィラーは、多孔質層の表面に微細な凹凸を形成することで滑り性を向上させ得る。フィラーが板状の粒子および/または凝集していない一次粒子である場合には、フィラーによって多孔質層の表面に形成される凹凸がより微細になり、多孔質層と電極との接着性がより良好となる。
The filler can improve slipperiness by forming fine irregularities on the surface of the porous layer. When the filler is a plate-like particle and / or a primary particle that is not aggregated, the unevenness formed on the surface of the porous layer by the filler becomes finer, and the adhesiveness between the porous layer and the electrode is further improved. It will be good.
本発明の一実施形態における多孔質層に含まれる、無機フィラーを構成する金属酸化物の酸素原子質量百分率は、10%~50%であることが好ましく、20%~50%であることがより好ましい。本明細書において、「酸素原子質量百分率」とは、金属酸化物全体の総質量に対する、当該金属酸化物中の酸素原子の質量の比を百分率で表したものを意味する。例えば、酸化亜鉛の場合、亜鉛の原子量:65.4、酸素の原子量:16.0より酸化亜鉛(ZnO)の分子量が65.4+16.0=81.4であることから、酸化亜鉛中の酸素原子質量百分率は16.0/81.4×100=20(%)である。
The oxygen atom mass percentage of the metal oxide constituting the inorganic filler contained in the porous layer in one embodiment of the present invention is preferably 10% to 50%, more preferably 20% to 50%. preferable. In the present specification, the "oxygen atom mass percentage" means the ratio of the mass of oxygen atoms in the metal oxide to the total mass of the entire metal oxide, expressed as a percentage. For example, in the case of zinc oxide, since the atomic weight of zinc is 65.4 and the atomic weight of oxygen is 16.0, the molecular weight of zinc oxide (ZnO) is 65.4 + 16.0 = 81.4. The atomic mass percentage is 16.0 / 81.4 × 100 = 20 (%).
前記金属酸化物の酸素原子質量百分率が上述の範囲であれば、後述する多孔質層の製造方法にて使用する塗工液中の溶媒または分散媒と、前記無機フィラーとの親和性を好適に保ち、前記無機フィラー間を適切な距離に保つことができる。これにより、塗工液の分散性を良好にすることができ、その結果、「多孔質層の表面の、無機フィラーの投影像のアスペクト比」および「多孔質層の配向度」を適切な規定範囲に制御することができる。
When the oxygen atom mass percentage of the metal oxide is in the above range, the affinity between the solvent or the dispersion medium in the coating liquid used in the method for producing a porous layer described later and the inorganic filler is preferably adjusted. It is possible to maintain the distance between the above-mentioned inorganic fillers at an appropriate distance. Thereby, the dispersibility of the coating liquid can be improved, and as a result, the "aspect ratio of the projected image of the inorganic filler on the surface of the porous layer" and the "orientation degree of the porous layer" can be defined appropriately. The range can be controlled.
本発明の一実施形態における多孔質層に含まれる、無機フィラー自体のアスペクト比は、無機フィラーを平面上に配置した状態で、配置面の垂直上方から観察したSEM像において、厚み方向に重なりあわない粒子100個の、短軸の長さ(短軸径)と長軸の長さ(長軸径)との比の平均値として表される。前記無機フィラー自体のアスペクト比は、1~10であることが好ましく、1.1~8であることがより好ましく、1.2~5であることがさらに好ましい。無機フィラー自体のアスペクト比が上述の範囲であることによって、後述する方法にて本発明の一実施形態における多孔質層を形成した際に、得られる多孔質層において、当該フィラーの配向性および多孔質層表面におけるフィラーの分布の均一性を好ましい範囲に制御することができる。
The aspect ratio of the inorganic filler itself contained in the porous layer in the embodiment of the present invention is such that, in a state where the inorganic filler is arranged on a plane, in the SEM image observed from vertically above the arrangement surface, the aspect ratio overlaps in the thickness direction. It is expressed as the average value of the ratio of the length of the minor axis (minor axis diameter) to the length of the major axis (minor axis diameter) of 100 particles that are not present. The aspect ratio of the inorganic filler itself is preferably 1 to 10, more preferably 1.1 to 8, and even more preferably 1.2 to 5. When the aspect ratio of the inorganic filler itself is in the above range, when the porous layer in one embodiment of the present invention is formed by the method described below, in the resulting porous layer, the orientation and porosity of the filler are It is possible to control the uniformity of the distribution of the filler on the surface of the quality layer in a preferable range.
本発明の一実施形態における多孔質層は、上述の無機フィラーおよび樹脂以外のその他の成分を含んでいてもよい。前記その他の成分としては、例えば、界面活性剤、ワックス、バインダー樹脂などを挙げることができる。また、前記その他の成分の含有量は、多孔質層全体の重量に対して、0重量%~50重量%であることが好ましい。
The porous layer in one embodiment of the present invention may contain other components than the above-mentioned inorganic filler and resin. Examples of the other components include surfactants, waxes and binder resins. The content of the other components is preferably 0% by weight to 50% by weight based on the weight of the entire porous layer.
本発明の一実施形態における多孔質層の平均膜厚は、電極との接着性および高エネルギー密度を確保する観点から、多孔質層一層当たり、0.5μm~10μmの範囲であることが好ましく、1μm~5μmの範囲であることがより好ましい。
The average film thickness of the porous layer in one embodiment of the present invention is preferably in the range of 0.5 μm to 10 μm per one layer of the porous layer from the viewpoint of ensuring adhesiveness to the electrode and high energy density. More preferably, it is in the range of 1 μm to 5 μm.
多孔質層の単位面積当たりの目付は、多孔質層の強度、膜厚、重量およびハンドリング性を考慮して適宜決定することができる。多孔質層の単位面積当たりの目付は、多孔質層一層当たり、0.5~20g/m2であることが好ましく、0.5~10g/m2であることがより好ましい。
The basis weight per unit area of the porous layer can be appropriately determined in consideration of the strength, film thickness, weight and handling property of the porous layer. The basis weight per unit area of the porous layer is preferably 0.5 to 20 g / m 2 and more preferably 0.5 to 10 g / m 2 per porous layer.
多孔質層の単位面積当たりの目付をこれらの数値範囲とすることにより、非水電解液二次電池の重量エネルギー密度および体積エネルギー密度を高くすることができる。多孔質層の目付が前記範囲を超える場合には、非水電解液二次電池が重くなる傾向がある。
By setting the basis weight per unit area of the porous layer within these numerical ranges, the weight energy density and volume energy density of the non-aqueous electrolyte secondary battery can be increased. When the basis weight of the porous layer exceeds the above range, the non-aqueous electrolyte secondary battery tends to be heavy.
多孔質層の空隙率は、充分なイオン透過性を得ることができるように、20~90体積%であることが好ましく、30~80体積%であることがより好ましい。また、多孔質層が有する細孔の孔径は、1.0μm以下であることが好ましく、0.5μm以下であることがより好ましい。細孔の孔径をこれらのサイズとすることにより、非水電解液二次電池は、充分なイオン透過性を得ることができる。
The porosity of the porous layer is preferably 20 to 90% by volume, and more preferably 30 to 80% by volume so that sufficient ion permeability can be obtained. The pore size of the pores of the porous layer is preferably 1.0 μm or less, more preferably 0.5 μm or less. By setting the pore diameters to these sizes, the non-aqueous electrolyte secondary battery can obtain sufficient ion permeability.
<多孔質層表面の無機フィラーの投影像のアスペクト比>
本発明の一実施形態における多孔質層は、当該多孔質層の表面の、無機フィラーの投影像のアスペクト比が、1.4~4.0の範囲であり、1.5~2.3の範囲であることが好ましい。ここで、前記アスペクト比は、走査型電子顕微鏡(SEM)を使用して、多孔質層の真上、すなわち鉛直上方から、その表面の電子顕微鏡写真であるSEM画像を撮影し、その写真から無機フィラーの投影像を作成し、当該無機フィラーの投影像の長軸の長さ/短軸の長さの比率を算出することによって求められる値である。なお、長軸の長さを長軸径、短軸の長さを短軸径とも称する。すなわち、前記アスペクト比とは、多孔質層の表面における無機フィラーを、多孔質層の真上方向から観測した場合に観測される当該無機フィラーの形状を示す。 <Aspect ratio of projected image of inorganic filler on porous layer surface>
In the porous layer according to the embodiment of the present invention, the aspect ratio of the projected image of the inorganic filler on the surface of the porous layer is in the range of 1.4 to 4.0 and is 1.5 to 2.3. It is preferably in the range. Here, for the aspect ratio, a scanning electron microscope (SEM) is used to take an SEM image, which is an electron micrograph of the surface, immediately above the porous layer, that is, from above the vertical direction. It is a value obtained by creating a projected image of the filler and calculating the ratio of the major axis length / minor axis length of the projected image of the inorganic filler. The length of the major axis is also referred to as the major axis diameter, and the length of the minor axis is also referred to as the minor axis diameter. That is, the aspect ratio refers to the shape of the inorganic filler observed when the inorganic filler on the surface of the porous layer is observed from directly above the porous layer.
本発明の一実施形態における多孔質層は、当該多孔質層の表面の、無機フィラーの投影像のアスペクト比が、1.4~4.0の範囲であり、1.5~2.3の範囲であることが好ましい。ここで、前記アスペクト比は、走査型電子顕微鏡(SEM)を使用して、多孔質層の真上、すなわち鉛直上方から、その表面の電子顕微鏡写真であるSEM画像を撮影し、その写真から無機フィラーの投影像を作成し、当該無機フィラーの投影像の長軸の長さ/短軸の長さの比率を算出することによって求められる値である。なお、長軸の長さを長軸径、短軸の長さを短軸径とも称する。すなわち、前記アスペクト比とは、多孔質層の表面における無機フィラーを、多孔質層の真上方向から観測した場合に観測される当該無機フィラーの形状を示す。 <Aspect ratio of projected image of inorganic filler on porous layer surface>
In the porous layer according to the embodiment of the present invention, the aspect ratio of the projected image of the inorganic filler on the surface of the porous layer is in the range of 1.4 to 4.0 and is 1.5 to 2.3. It is preferably in the range. Here, for the aspect ratio, a scanning electron microscope (SEM) is used to take an SEM image, which is an electron micrograph of the surface, immediately above the porous layer, that is, from above the vertical direction. It is a value obtained by creating a projected image of the filler and calculating the ratio of the major axis length / minor axis length of the projected image of the inorganic filler. The length of the major axis is also referred to as the major axis diameter, and the length of the minor axis is also referred to as the minor axis diameter. That is, the aspect ratio refers to the shape of the inorganic filler observed when the inorganic filler on the surface of the porous layer is observed from directly above the porous layer.
なお、上述の多孔質層表面のSEM画像から作成される無機フィラーの投影像の模式図を図2に示す。
Note that FIG. 2 shows a schematic diagram of a projected image of the inorganic filler created from the SEM image of the surface of the porous layer described above.
前記アスペクト比の具体的な測定法としては、例えば、以下の(1)~(4)に示す工程からなる方法が挙げられる。なお、多孔質層の「表面」とは、多孔質層の真上からSEMによって観察可能な多孔質層の面をいう。
(1)多孔質層を基材上に積層させてなる積層体において、当該積層体の多孔質側の真上から日本電子製 電界放出形走査電子顕微鏡JSM-7600Fを用いて加速電圧5kVでSEM表面観察(反射電子像)を行い、SEM画像を得る工程。
(2)工程(1)にて得られたSEM画像上にOHPフィルムを載せ、当該SEM画像に写っている無機フィラーの粒子の輪郭に沿って敷き写した投影像を作成し、該投影像をデジタルスチルカメラにより撮影する工程。
(3)工程(2)にて得られた写真のデータをコンピュータに取り込み、アメリカ国立衛生研究所(NIH:National Institues of Health)が発行する画像解析のフリーソフトIMAGEJを用いて、前記フィラー粒子100個の各々のアスペクト比を算出する工程。なお、ここで前記フィラー粒子を1粒子ずつ楕円形に近似させ、長軸径と短軸径を算出し、長軸径を短軸径で除した値をアスペクト比とする。
(4)工程(3)にて得られたそれぞれの粒子の投影像のアスペクト比の平均値を算出し、その値を多孔質層表面の無機フィラーの投影像のアスペクト比とする工程。 As a specific measuring method of the aspect ratio, for example, a method including the following steps (1) to (4) can be mentioned. The “surface” of the porous layer means the surface of the porous layer that can be observed by SEM from directly above the porous layer.
(1) In a laminated body in which a porous layer is laminated on a substrate, an SEM at an accelerating voltage of 5 kV is used from directly above the porous side of the laminated body by using a field emission scanning electron microscope JSM-7600F manufactured by JEOL Ltd. A step of observing the surface (reflected electron image) to obtain an SEM image.
(2) An OHP film is placed on the SEM image obtained in the step (1), a projection image laid along the contour of the particles of the inorganic filler shown in the SEM image is created, and the projection image is obtained. The process of shooting with a digital still camera.
(3) The photographic data obtained in the step (2) is loaded into a computer, and the filler particles 100 are filled with the image analysis free software IMAGEJ issued by the National Institutes of Health (NIH). Calculating the aspect ratio of each of the pieces. Here, each of the filler particles is approximated to an ellipse one by one, the major axis diameter and the minor axis diameter are calculated, and the value obtained by dividing the major axis diameter by the minor axis diameter is defined as an aspect ratio.
(4) A step of calculating the average value of the aspect ratios of the projected images of the respective particles obtained in the step (3), and using that value as the aspect ratio of the projected image of the inorganic filler on the surface of the porous layer.
(1)多孔質層を基材上に積層させてなる積層体において、当該積層体の多孔質側の真上から日本電子製 電界放出形走査電子顕微鏡JSM-7600Fを用いて加速電圧5kVでSEM表面観察(反射電子像)を行い、SEM画像を得る工程。
(2)工程(1)にて得られたSEM画像上にOHPフィルムを載せ、当該SEM画像に写っている無機フィラーの粒子の輪郭に沿って敷き写した投影像を作成し、該投影像をデジタルスチルカメラにより撮影する工程。
(3)工程(2)にて得られた写真のデータをコンピュータに取り込み、アメリカ国立衛生研究所(NIH:National Institues of Health)が発行する画像解析のフリーソフトIMAGEJを用いて、前記フィラー粒子100個の各々のアスペクト比を算出する工程。なお、ここで前記フィラー粒子を1粒子ずつ楕円形に近似させ、長軸径と短軸径を算出し、長軸径を短軸径で除した値をアスペクト比とする。
(4)工程(3)にて得られたそれぞれの粒子の投影像のアスペクト比の平均値を算出し、その値を多孔質層表面の無機フィラーの投影像のアスペクト比とする工程。 As a specific measuring method of the aspect ratio, for example, a method including the following steps (1) to (4) can be mentioned. The “surface” of the porous layer means the surface of the porous layer that can be observed by SEM from directly above the porous layer.
(1) In a laminated body in which a porous layer is laminated on a substrate, an SEM at an accelerating voltage of 5 kV is used from directly above the porous side of the laminated body by using a field emission scanning electron microscope JSM-7600F manufactured by JEOL Ltd. A step of observing the surface (reflected electron image) to obtain an SEM image.
(2) An OHP film is placed on the SEM image obtained in the step (1), a projection image laid along the contour of the particles of the inorganic filler shown in the SEM image is created, and the projection image is obtained. The process of shooting with a digital still camera.
(3) The photographic data obtained in the step (2) is loaded into a computer, and the filler particles 100 are filled with the image analysis free software IMAGEJ issued by the National Institutes of Health (NIH). Calculating the aspect ratio of each of the pieces. Here, each of the filler particles is approximated to an ellipse one by one, the major axis diameter and the minor axis diameter are calculated, and the value obtained by dividing the major axis diameter by the minor axis diameter is defined as an aspect ratio.
(4) A step of calculating the average value of the aspect ratios of the projected images of the respective particles obtained in the step (3), and using that value as the aspect ratio of the projected image of the inorganic filler on the surface of the porous layer.
前記多孔質層表面の無機フィラーの投影像のアスペクト比は、多孔質層、特にその表面における無機フィラーの分布の均一性を示す指標である。前記アスペクト比が1に近いということは、多孔質層表面の構成材の形状ならびに分布が均一であり、密に充填されやすいことを示す。一方、前記アスペクト比が大きいことは、多孔質層の表面構造における構成成分の配置が不均一になり、結果として、多孔質層表面開口部の形状並びに分布の均一性が低下することを示す。
The aspect ratio of the projected image of the inorganic filler on the surface of the porous layer is an index showing the uniformity of the distribution of the inorganic filler on the porous layer, especially on the surface thereof. When the aspect ratio is close to 1, it means that the constituent material on the surface of the porous layer has a uniform shape and distribution, and is easily packed densely. On the other hand, when the aspect ratio is large, the arrangement of the constituent components in the surface structure of the porous layer becomes non-uniform, and as a result, the uniformity of the shape and distribution of the openings of the surface of the porous layer deteriorates.
前記アスペクト比が4.0より大きい場合には、多孔質層、特にその表面開口部の形状並びに分布の均一性が、過度に低下すると考えられる。そのため、前記多孔質層を組み込んだ非水電解液二次電池において、電池作動時の多孔質層の電解液受入能力が低下する箇所が生じ、その結果、当該非水電解液二次電池のレート特性が低下すると考えられる。一方、前記アスペクト比が1.4未満である場合には、多孔質層、特にその表面の無機フィラーの分布が、過度に均一化された構造となり、結果として多孔質層の表面開口部面積が小さくなると考えられる。そのため、前記多孔質層を組み込んだ非水電解液二次電池において、電池作動時の多孔質層の電解液受入能力が低下し、その結果、当該非水電解液二次電池の電池レート特性が低下すると考えられる。
If the aspect ratio is greater than 4.0, it is considered that the uniformity of the shape and distribution of the porous layer, especially the surface openings, is excessively reduced. Therefore, in the non-aqueous electrolyte secondary battery incorporating the porous layer, a portion where the electrolyte receiving capacity of the porous layer at the time of battery operation is reduced occurs, as a result, the rate of the non-aqueous electrolyte secondary battery. It is considered that the characteristics are degraded. On the other hand, when the aspect ratio is less than 1.4, the porous layer, in particular, the distribution of the inorganic filler on the surface thereof has an excessively uniform structure, and as a result, the surface opening area of the porous layer is small. It will be smaller. Therefore, in the non-aqueous electrolyte secondary battery incorporating the porous layer, the electrolyte receiving ability of the porous layer at the time of battery operation is reduced, as a result, the battery rate characteristics of the non-aqueous electrolyte secondary battery It is expected to decrease.
<多孔質層の配向度>
本発明の一実施形態における多孔質層は、広角X線回折法により測定した、当該多孔質層における互いに直交する任意の回折面(hkl)、(abc)のピーク強度:I(hkl)およびI(abc)が下式(1)を満たし、かつ、下式(2)で算出されるピーク強度比の最大値の範囲が、1.5~300の範囲であることが好ましく、1.5~250の範囲であることがより好ましい。
I(hkl) > I(abc)・・・(1)、
I(hkl) / I(abc)・・・(2)。 <Orientation of porous layer>
The porous layer according to one embodiment of the present invention has a peak intensity of arbitrary diffraction planes (hkl), (abc) orthogonal to each other in the porous layer measured by a wide-angle X-ray diffraction method: I (hkl) and I It is preferable that (abc) satisfies the following formula (1) and the maximum value of the peak intensity ratio calculated by the following formula (2) is in the range of 1.5 to 300, preferably 1.5 to 300. The range of 250 is more preferable.
I (hkl) > I (abc) ... (1),
I (hkl) / I (abc) (2).
本発明の一実施形態における多孔質層は、広角X線回折法により測定した、当該多孔質層における互いに直交する任意の回折面(hkl)、(abc)のピーク強度:I(hkl)およびI(abc)が下式(1)を満たし、かつ、下式(2)で算出されるピーク強度比の最大値の範囲が、1.5~300の範囲であることが好ましく、1.5~250の範囲であることがより好ましい。
I(hkl) > I(abc)・・・(1)、
I(hkl) / I(abc)・・・(2)。 <Orientation of porous layer>
The porous layer according to one embodiment of the present invention has a peak intensity of arbitrary diffraction planes (hkl), (abc) orthogonal to each other in the porous layer measured by a wide-angle X-ray diffraction method: I (hkl) and I It is preferable that (abc) satisfies the following formula (1) and the maximum value of the peak intensity ratio calculated by the following formula (2) is in the range of 1.5 to 300, preferably 1.5 to 300. The range of 250 is more preferable.
I (hkl) > I (abc) ... (1),
I (hkl) / I (abc) (2).
以下、本明細書において、前記式(2)で算出されるピーク強度比の最大値を、「多孔質層の配向度」とも称する。
Hereinafter, in this specification, the maximum value of the peak intensity ratio calculated by the above formula (2) is also referred to as “the orientation degree of the porous layer”.
前記ピーク強度I(hkl)およびI(abc)、並びに、ピーク強度比I(hkl) / I(abc)を測定する方法は、特に限定されないが、例えば、以下の(1)~(3)に示す工程からなる方法を挙げることができる。
(1)多孔質層を基材上に積層させてなる積層体(積層多孔質フィルム)を2cm角に切り取り、測定用サンプルを作製する工程。
(2)工程(1)にて得られた測定用サンプルを、当該サンプルにおける多孔質層側を測定面として、Al製ホルダーに取り付け広角X線回折法(2θ―θスキャン法)でX線プロファイルを測定する工程。なお、前記X線プロファイルを測定する装置および測定条件は、特に限定されないが、例えば、装置として理学電機社製RU-200R(回転対陰極型)を使用し、X線源にCuKα線を用い、出力は50KV-200mA、スキャン速度2°/minにて測定する方法が挙げられる。
(3)工程(2)にて得られるX線プロファイルに基づき、多孔質層の広角X線回折測定における、お互いに直交する任意の回折面(hkl)、(abc)のピーク強度 I(hkl)およびI(abc)が前記式(1)を満たす場合に、前記式(2)で算出されるピーク強度比を算出し、そのピーク強度比の最大値、すなわち多孔質層の配向度を算出する工程。 The method for measuring the peak intensities I (hkl) and I (abc) and the peak intensity ratio I (hkl) / I (abc) is not particularly limited. For example, the following (1) to (3) are used. A method comprising the steps shown can be mentioned.
(1) A step of preparing a measurement sample by cutting a 2 cm square laminate (laminated porous film) obtained by laminating a porous layer on a substrate.
(2) The measurement sample obtained in step (1) was attached to an Al holder with the porous layer side of the sample as the measurement surface, and an X-ray profile was obtained by a wide-angle X-ray diffraction method (2θ-θ scan method). Measuring step. The device for measuring the X-ray profile and the measurement conditions are not particularly limited. For example, RU-200R (rotating anticathode type) manufactured by Rigaku Denki Co., Ltd. is used as the device, and CuKα rays are used as the X-ray source. The output may be measured at 50 KV-200 mA and a scanning speed of 2 ° / min.
(3) Based on the X-ray profile obtained in step (2), peak intensity I (hkl) of arbitrary diffraction planes (hkl) and (abc) orthogonal to each other in wide-angle X-ray diffraction measurement of the porous layer And I (abc) satisfy the equation (1), the peak intensity ratio calculated by the equation (2) is calculated, and the maximum value of the peak intensity ratio, that is, the degree of orientation of the porous layer is calculated. Process.
(1)多孔質層を基材上に積層させてなる積層体(積層多孔質フィルム)を2cm角に切り取り、測定用サンプルを作製する工程。
(2)工程(1)にて得られた測定用サンプルを、当該サンプルにおける多孔質層側を測定面として、Al製ホルダーに取り付け広角X線回折法(2θ―θスキャン法)でX線プロファイルを測定する工程。なお、前記X線プロファイルを測定する装置および測定条件は、特に限定されないが、例えば、装置として理学電機社製RU-200R(回転対陰極型)を使用し、X線源にCuKα線を用い、出力は50KV-200mA、スキャン速度2°/minにて測定する方法が挙げられる。
(3)工程(2)にて得られるX線プロファイルに基づき、多孔質層の広角X線回折測定における、お互いに直交する任意の回折面(hkl)、(abc)のピーク強度 I(hkl)およびI(abc)が前記式(1)を満たす場合に、前記式(2)で算出されるピーク強度比を算出し、そのピーク強度比の最大値、すなわち多孔質層の配向度を算出する工程。 The method for measuring the peak intensities I (hkl) and I (abc) and the peak intensity ratio I (hkl) / I (abc) is not particularly limited. For example, the following (1) to (3) are used. A method comprising the steps shown can be mentioned.
(1) A step of preparing a measurement sample by cutting a 2 cm square laminate (laminated porous film) obtained by laminating a porous layer on a substrate.
(2) The measurement sample obtained in step (1) was attached to an Al holder with the porous layer side of the sample as the measurement surface, and an X-ray profile was obtained by a wide-angle X-ray diffraction method (2θ-θ scan method). Measuring step. The device for measuring the X-ray profile and the measurement conditions are not particularly limited. For example, RU-200R (rotating anticathode type) manufactured by Rigaku Denki Co., Ltd. is used as the device, and CuKα rays are used as the X-ray source. The output may be measured at 50 KV-200 mA and a scanning speed of 2 ° / min.
(3) Based on the X-ray profile obtained in step (2), peak intensity I (hkl) of arbitrary diffraction planes (hkl) and (abc) orthogonal to each other in wide-angle X-ray diffraction measurement of the porous layer And I (abc) satisfy the equation (1), the peak intensity ratio calculated by the equation (2) is calculated, and the maximum value of the peak intensity ratio, that is, the degree of orientation of the porous layer is calculated. Process.
なお、多孔質層の配向度の算出において、互いに直交する回折面を用いることにより、基材面に対して水平方向の向きと、法線方向の向きとの両方が決定されることが重要である。
In the calculation of the degree of orientation of the porous layer, it is important to determine both the orientation in the horizontal direction and the orientation in the normal direction with respect to the substrate surface by using the diffractive surfaces orthogonal to each other. is there.
前記式(2)にて示されるピーク強度比の最大値は、多孔質層内部の配向度を示す指標である。前記式(2)にて示されるピーク強度比が小さいことは、多孔質層の内部構造における配向度が低いことを示し、前記式(2)にて示されるピーク強度比が大きいことは、多孔質層の内部構造における配向度が高いことを示す。
The maximum value of the peak intensity ratio shown by the above formula (2) is an index showing the degree of orientation inside the porous layer. A small peak intensity ratio represented by the formula (2) means that the degree of orientation in the internal structure of the porous layer is low, and a large peak intensity ratio represented by the formula (2) means that It shows that the internal structure of the texture layer has a high degree of orientation.
前記式(2)にて示されるピーク強度比の最大値が300より大きい場合には、多孔質層内部構造の異方性が過度に高い構造となり、多孔質層内部のイオン透過流路長が長くなる。その結果、前記多孔質層を組み込んだ非水電解液二次電池において、多孔質層のイオン透過抵抗が増加し、当該非水電解液二次電池の電池レート特性が低下すると考えられる。
When the maximum value of the peak intensity ratio represented by the formula (2) is larger than 300, the anisotropy of the internal structure of the porous layer becomes excessively high, and the ion permeation flow channel length inside the porous layer is increased. become longer. As a result, in the non-aqueous electrolyte secondary battery incorporating the porous layer, it is considered that the ion permeation resistance of the porous layer increases and the battery rate characteristics of the non-aqueous electrolyte secondary battery deteriorate.
一方、前記式(2)にて示されるピーク強度比の最大値が1.5未満である場合には、1.5以上のピーク強度比を有する多孔質層を用いたケースに比べて、前記多孔質層を組み込んだ非水電解液二次電池において、電極から供給されるイオンを高速で透過させる。これにより、電極からのイオン供給が律速となるため、つまり、電極表面でイオンが枯渇するため、電池作動電流値条件である限界電流が小さくなり、結果として、当該非水電解液二次電池の電池レート特性が低下すると考えられる。
On the other hand, when the maximum value of the peak intensity ratio represented by the above formula (2) is less than 1.5, compared to the case where the porous layer having the peak intensity ratio of 1.5 or more is used, In a non-aqueous electrolyte secondary battery incorporating a porous layer, the ions supplied from the electrodes are permeated at high speed. Thereby, since the ion supply from the electrode is rate-determining, that is, the ions are depleted on the electrode surface, the limiting current that is the battery operating current value condition becomes small, and as a result, the non-aqueous electrolyte secondary battery It is considered that the battery rate characteristic deteriorates.
<多孔質層の製造方法>
本発明の一実施形態における多孔質層の製造方法としては、特に限定されないが、例えば、基材上に、以下に示す工程(1)~(3)の何れかの1つの工程を用いて、前記無機フィラーと前記樹脂とを含む多孔質層を形成する方法を挙げることができる。以下に示す工程(2)および工程(3)の場合においては、前記樹脂を析出させた後にさらに乾燥させ、溶媒を除去することによって、多孔質層が製造され得る。工程(1)~(3)における塗工液は、前記無機フィラーが分散しており、かつ、前記樹脂が溶解している状態であってもよい。なお、前記溶媒は、樹脂を溶解させる溶媒であるとともに、樹脂または無機フィラーを分散させる分散媒であるとも言える。 <Method for producing porous layer>
The method for producing the porous layer according to the embodiment of the present invention is not particularly limited, but for example, one of the following steps (1) to (3) may be used on the substrate, A method of forming a porous layer containing the inorganic filler and the resin can be mentioned. In the case of the step (2) and the step (3) shown below, the porous layer can be produced by depositing the resin and then drying it to remove the solvent. The coating liquid in steps (1) to (3) may be in a state in which the inorganic filler is dispersed and the resin is dissolved. The solvent can be said to be a solvent for dissolving the resin and a dispersion medium for dispersing the resin or the inorganic filler.
本発明の一実施形態における多孔質層の製造方法としては、特に限定されないが、例えば、基材上に、以下に示す工程(1)~(3)の何れかの1つの工程を用いて、前記無機フィラーと前記樹脂とを含む多孔質層を形成する方法を挙げることができる。以下に示す工程(2)および工程(3)の場合においては、前記樹脂を析出させた後にさらに乾燥させ、溶媒を除去することによって、多孔質層が製造され得る。工程(1)~(3)における塗工液は、前記無機フィラーが分散しており、かつ、前記樹脂が溶解している状態であってもよい。なお、前記溶媒は、樹脂を溶解させる溶媒であるとともに、樹脂または無機フィラーを分散させる分散媒であるとも言える。 <Method for producing porous layer>
The method for producing the porous layer according to the embodiment of the present invention is not particularly limited, but for example, one of the following steps (1) to (3) may be used on the substrate, A method of forming a porous layer containing the inorganic filler and the resin can be mentioned. In the case of the step (2) and the step (3) shown below, the porous layer can be produced by depositing the resin and then drying it to remove the solvent. The coating liquid in steps (1) to (3) may be in a state in which the inorganic filler is dispersed and the resin is dissolved. The solvent can be said to be a solvent for dissolving the resin and a dispersion medium for dispersing the resin or the inorganic filler.
(1)前記無機フィラーおよび前記樹脂の微粒子を含む塗工液を、基材上に塗工し、前記塗工液中の溶媒を乾燥除去することによって多孔質層を形成させる工程。
(1) A step of forming a porous layer by applying a coating liquid containing the inorganic filler and fine particles of the resin on a base material and drying and removing the solvent in the coating liquid.
(2)前記無機フィラーおよび前記樹脂を含む塗工液を、前記基材の表面に塗工した後、その基材を前記樹脂に対して貧溶媒である、析出溶媒に浸漬することによって、前記樹脂を析出させ、多孔質層を形成する工程。
(2) After applying a coating liquid containing the inorganic filler and the resin on the surface of the base material, the base material is immersed in a deposition solvent that is a poor solvent for the resin, A step of depositing a resin to form a porous layer.
(3)前記無機フィラーおよび前記樹脂を含む塗工液を、前記基材の表面に塗工した後、低沸点有機酸を用いて、前記塗工液の液性を酸性にすることによって、前記樹脂を析出させ、多孔質層を形成する工程。
(3) After coating a coating liquid containing the inorganic filler and the resin on the surface of the base material, the liquid property of the coating liquid is made acidic by using a low-boiling organic acid, A step of depositing a resin to form a porous layer.
前記基材には、後述するポリオレフィン多孔質フィルムの他に、その他のフィルム、正極および負極などを用いることができる。
In addition to the polyolefin porous film described below, other films, a positive electrode, a negative electrode, and the like can be used as the base material.
前記溶媒は基材に悪影響を及ぼさず、前記樹脂を均一かつ安定に溶解し、前記無機フィラーを均一かつ安定に分散させる溶媒であることが好ましい。前記溶媒としては、例えば、N-メチル-2-ピロリドン、N,N-ジメチルアセトアミド、N,N-ジメチルホルムアミド、アセトンおよび水等が挙げられる。
Preferably, the solvent does not adversely affect the base material, dissolves the resin uniformly and stably, and disperses the inorganic filler uniformly and stably. Examples of the solvent include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, acetone and water.
前記析出溶媒としては、例えば、イソプロピルアルコールまたはt-ブチルアルコールを用いることが好ましい。
As the deposition solvent, for example, isopropyl alcohol or t-butyl alcohol is preferably used.
前記工程(3)において、低沸点有機酸としては、例えば、パラトルエンスルホン酸、酢酸等を使用することができる。
In the step (3), as the low boiling point organic acid, for example, paratoluenesulfonic acid, acetic acid, etc. can be used.
また、本発明の一実施形態における多孔質層の配向性、すなわち、「多孔質層表面の無機フィラーの投影像のアスペクト比」および「多孔質層の配向度」を制御する方法として、以下に示すように、多孔質層の製造に使用する、前記無機フィラーおよび前記樹脂を含む塗工液の固形分濃度、並びに、前記塗工液を基材上に塗工する際の塗工せん断速度を調節することを挙げることができる。
In addition, as a method of controlling the orientation of the porous layer in one embodiment of the present invention, that is, the “aspect ratio of the projected image of the inorganic filler on the surface of the porous layer” and the “degree of orientation of the porous layer”, As shown, used in the production of the porous layer, the solid content concentration of the coating liquid containing the inorganic filler and the resin, and the coating shear rate when coating the coating liquid on the substrate The adjustment can be mentioned.
前記塗工液の好適な固形分濃度は、フィラーの種類などによって変化し得るが、一般には、20重量%より大きく40重量%以下であることが好ましい。前記固形分濃度が上述の範囲であることは、前記塗工液の粘度を適切に保ち、その結果、「多孔質層表面の無機フィラーの投影像のアスペクト比」および「多孔質層の配向度」を上述の好適な範囲に制御することができるため好ましい。
A suitable solid content concentration of the coating liquid may vary depending on the type of filler, etc., but generally it is preferably more than 20% by weight and 40% by weight or less. That the solid content concentration is in the above range, the viscosity of the coating liquid is appropriately maintained, and as a result, the “aspect ratio of the projected image of the inorganic filler on the surface of the porous layer” and the “degree of orientation of the porous layer”. Is preferable because it can be controlled within the above-mentioned preferable range.
前記塗工液を基材上に塗工する際の塗工せん断速度は、フィラーの種類などによって変化し得るが、一般には、2(1/s)以上であることが好ましく、4(1/s)~50(1/s)であることがより好ましい。
The coating shear rate at the time of applying the coating liquid on the substrate may vary depending on the type of filler, etc., but generally it is preferably 2 (1 / s) or more and 4 (1 / s). More preferably, it is from s) to 50 (1 / s).
ここで、例えば、前記無機フィラーとして、ピーナッツ状および/またはテトラポット状のように球状または柱状の単一粒子が熱融着した形状、球形状、楕円形状、板状、棒状、または、不定形状の形状を有する無機フィラーを用いた場合、前記塗工せん断速度を大きくすると、高せん断力が無機フィラーにかかるため、異方性が高くなる傾向がある。一方、前記塗工せん断速度を小さくするとせん断力が無機フィラーにかからないため、等方的に配向する傾向がある。
Here, for example, as the inorganic filler, a shape in which spherical or columnar single particles such as peanut-shaped and / or tetrapot-shaped are heat-fused, spherical-shaped, elliptical-shaped, plate-shaped, rod-shaped, or irregular-shaped. When an inorganic filler having the above-mentioned shape is used, if the coating shear rate is increased, a high shearing force is applied to the inorganic filler, so that the anisotropy tends to increase. On the other hand, when the coating shear rate is reduced, the shearing force is not applied to the inorganic filler, so that the inorganic filler tends to be oriented isotropically.
一方、前記無機フィラーが繊維径の長いワラストナイトのような長繊維径無機フィラーである場合には、前記塗工せん断速度を大きくすると、長繊維どうしが絡み合う、あるいはドクターブレードの刃に長繊維がひっかかるためばらばらの配向になり、異方性が低くなる傾向がある。一方、前記塗工せん断速度を小さくすると、長繊維が、互いに絡み合うことがなく、ドクターブレードの刃にひっかからないので、配向しやすくなり、異方性は高くなる傾向がある。
On the other hand, when the inorganic filler is a long fiber diameter inorganic filler such as long wollastonite having a large fiber diameter, when the coating shear rate is increased, the long fibers are entangled with each other, or the long blades of the doctor blade are long fibers. Tend to be in a disoriented orientation due to the trapping of the, and anisotropy tends to be low. On the other hand, when the coating shear rate is reduced, the long fibers do not become entangled with each other and do not get caught by the blade of the doctor blade, so that they tend to be oriented and the anisotropy tends to increase.
[非水電解液]
本発明の一実施形態における非水電解液は、下記式(A)で表されるイオン電導度低下率Lが1.0%以上、6.0%以下である添加剤を0.5ppm~300ppm含有する。
L=(LA-LB)/LA・・・(A)
式(A)中、LAは、エチレンカーボネート、エチルメチルカーボネートおよびジエチルカーボネートを3:5:2の体積比で含む混合溶媒に、LiPF6をその濃度が1mol/Lとなるように溶解させた参照用電解液のイオン電導度(mS/cm)を表す。LBは、前記参照用電解液に、添加剤を1.0重量%溶解させた電解液のイオン電導度(mS/cm)を表す。 [Non-aqueous electrolyte]
The non-aqueous electrolyte in one embodiment of the present invention contains an additive having an ionic conductivity decrease rate L represented by the following formula (A) of 1.0% or more and 6.0% or less, 0.5 ppm to 300 ppm. contains.
L = (LA-LB) / LA ... (A)
In formula (A), LA is a reference in which LiPF 6 is dissolved in a mixed solvent containing ethylene carbonate, ethylmethyl carbonate and diethyl carbonate in a volume ratio of 3: 5: 2 so that the concentration becomes 1 mol / L. The ionic conductivity (mS / cm) of the electrolyte for use is shown. LB represents the ionic conductivity (mS / cm) of the electrolytic solution prepared by dissolving 1.0% by weight of the additive in the reference electrolytic solution.
本発明の一実施形態における非水電解液は、下記式(A)で表されるイオン電導度低下率Lが1.0%以上、6.0%以下である添加剤を0.5ppm~300ppm含有する。
L=(LA-LB)/LA・・・(A)
式(A)中、LAは、エチレンカーボネート、エチルメチルカーボネートおよびジエチルカーボネートを3:5:2の体積比で含む混合溶媒に、LiPF6をその濃度が1mol/Lとなるように溶解させた参照用電解液のイオン電導度(mS/cm)を表す。LBは、前記参照用電解液に、添加剤を1.0重量%溶解させた電解液のイオン電導度(mS/cm)を表す。 [Non-aqueous electrolyte]
The non-aqueous electrolyte in one embodiment of the present invention contains an additive having an ionic conductivity decrease rate L represented by the following formula (A) of 1.0% or more and 6.0% or less, 0.5 ppm to 300 ppm. contains.
L = (LA-LB) / LA ... (A)
In formula (A), LA is a reference in which LiPF 6 is dissolved in a mixed solvent containing ethylene carbonate, ethylmethyl carbonate and diethyl carbonate in a volume ratio of 3: 5: 2 so that the concentration becomes 1 mol / L. The ionic conductivity (mS / cm) of the electrolyte for use is shown. LB represents the ionic conductivity (mS / cm) of the electrolytic solution prepared by dissolving 1.0% by weight of the additive in the reference electrolytic solution.
前記添加剤は、式(A)で表されるイオン電導度低下率Lが1.0%以上、6.0%以下であることを充足する化合物であれば特に限定されない。そのような化合物としては、例えば、ペンタエリトリトールテトラキス[3-(3,5-ジ-tert-ブチル-4-ヒドロキシフェニル)プロピオナート]、トリエチルフォスフェイト、ビニレンカーボネート、プロパンサルトン、2,6-ジ-tert-ブチル-4-メチルフェノール、6-[3-(3-t-ブチル-4-ヒドロキシ-5-メチルフェニル)プロポキシ]-2,4,8,10-テトラ-t-ブチルジベンゾ[d,f][1,3,2]ジオキサホスフェピン、リン酸トリス(2,4-ジ-tert-ブチルフェニル)、2-[1-(2-ヒドロキシ-3,5-ジ-tert-ペンチルフェニル)エチル]-4,6-ジ-tert-ペンチルフェニルアクリレート、ジブチルヒドロキシトルエン等を挙げることができる。
The additive is not particularly limited as long as it is a compound that satisfies the ionic conductivity reduction rate L represented by the formula (A) of 1.0% or more and 6.0% or less. Examples of such a compound include pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], triethyl phosphate, vinylene carbonate, propane sultone, 2,6-dione. -Tert-butyl-4-methylphenol, 6- [3- (3-t-butyl-4-hydroxy-5-methylphenyl) propoxy] -2,4,8,10-tetra-t-butyldibenzo [d , F] [1,3,2] dioxaphosphine, tris (2,4-di-tert-butylphenyl) phosphate, 2- [1- (2-hydroxy-3,5-di-tert-) Pentylphenyl) ethyl] -4,6-di-tert-pentylphenyl acrylate, dibutylhydroxytoluene and the like can be mentioned.
非水電解液は、電解質と有機溶媒とを含む。前記電解質としては、リチウムを含有している電解質が挙げられる。リチウムを含有している電解質としては、例えば、LiClO4、LiPF6、LiAsF6、LiSbF6、LiBF4、LiCF3SO3、LiN(CF3SO2)2、LiC(CF3SO2)3、Li2B10Cl10、低級脂肪族カルボン酸リチウム塩およびLiAlCl4等のリチウム塩、等の金属塩が挙げられる。前記電解質は、1種類のみを用いてもよく、2種類以上を組み合わせて用いてもよい。
The non-aqueous electrolytic solution contains an electrolyte and an organic solvent. Examples of the electrolyte include an electrolyte containing lithium. As the electrolyte containing lithium, for example, LiClO 4, LiPF 6, LiAsF 6, LiSbF 6, LiBF 4, LiCF 3 SO 3, LiN (CF 3 SO 2) 2, LiC (CF 3 SO 2) 3, Examples thereof include metal salts such as Li 2 B 10 Cl 10 , lithium salts of lower aliphatic carboxylic acids and lithium salts such as LiAlCl 4 . The electrolyte may be used alone or in combination of two or more kinds.
前記非水電解液を構成する有機溶媒としては、例えば、カーボネート類、エーテル類、エステル類、ニトリル類、アミド類、カーバメート類および含硫黄化合物、並びにこれらの有機溶媒にフッ素基が導入されてなる含フッ素有機溶媒等の非プロトン性極性溶媒が挙げられる。前記有機溶媒は、1種類のみを用いてもよく、2種類以上を組み合わせて用いてもよい。
Examples of the organic solvent that constitutes the non-aqueous electrolytic solution include carbonates, ethers, esters, nitriles, amides, carbamates and sulfur-containing compounds, and fluorine groups introduced into these organic solvents. An aprotic polar solvent such as a fluorine-containing organic solvent may be used. The organic solvent may be used alone or in combination of two or more.
前記有機溶媒は、前記参照用電解液と同様に、エチレンカーボネート等の環状化合物とエチルメチルカーボネート、ジエチルカーボネート等の鎖状化合物とを含む混合溶媒であることが好ましい。前記混合溶媒は、前記環状化合物と、前記鎖状化合物とを、好ましくは2:8~4:6の体積比で含み、より好ましくは2:8~3:7の体積比で含み、特に好ましくは3:7の体積比で含む。なお、環状化合物および鎖状化合物を3:7の体積比にて混合した混合溶媒は、非水電解液二次電池の非水電解液に、特に一般に使用される有機溶媒である。
Like the reference electrolyte, the organic solvent is preferably a mixed solvent containing a cyclic compound such as ethylene carbonate and a chain compound such as ethylmethyl carbonate and diethyl carbonate. The mixed solvent contains the cyclic compound and the chain compound preferably in a volume ratio of 2: 8 to 4: 6, more preferably in a volume ratio of 2: 8 to 3: 7, and particularly preferably. Is included in a volume ratio of 3: 7. The mixed solvent in which the cyclic compound and the chain compound are mixed at a volume ratio of 3: 7 is an organic solvent that is generally used in the non-aqueous electrolyte solution of the non-aqueous electrolyte secondary battery.
本発明の一実施形態における添加剤は、前記参照用電解液のイオン電導度を低下させるものである。前記添加剤を非水電解液に添加することにより、ハイレート放電後の充電容量の低下を抑制できる理由としては、例えば、以下の理由が考えられる。前記添加剤を添加することによって、前記非水電解液中のイオンの解離度が低下し得る。これにより、充放電時、特に高速で電池を作動させた際の、セパレータと電極との界面におけるイオンの枯渇が低減され得る。それによって、ハイレート放電後の充電容量の低下を抑制できる、と考えられる。
The additive in one embodiment of the present invention reduces the ionic conductivity of the reference electrolyte solution. The following reasons can be considered as reasons why the reduction of the charge capacity after high-rate discharge can be suppressed by adding the additive to the non-aqueous electrolyte solution. By adding the additive, the dissociation degree of ions in the non-aqueous electrolyte may be reduced. This can reduce the depletion of ions at the interface between the separator and the electrode during charge / discharge, particularly when the battery is operated at high speed. Therefore, it is considered that the reduction of the charge capacity after the high rate discharge can be suppressed.
電極近傍におけるイオンの枯渇を低減させるという観点から、前記非水電解液は、前記添加剤を0.5ppm以上含有し、20ppm以上含有することが好ましく、45ppm以上含有することがより好ましい。
From the viewpoint of reducing the depletion of ions near the electrodes, the non-aqueous electrolyte solution contains the additive in an amount of 0.5 ppm or more, preferably 20 ppm or more, and more preferably 45 ppm or more.
一方、前記添加剤の含有量が過剰に多い場合、非水電解液全体のイオンの解離度が過剰に低下することにより、非水電解液二次電池全体におけるイオンの流れが阻害されると考えられる。従って、かえってハイレート放電後の充電容量等の電池特性が低下するおそれがある。非水電解液二次電池全体におけるイオンの流れの阻害を抑制するとの観点から、前記非水電解液は、前記添加剤を300ppm以下含有し、250ppm以下含有することが好ましく、180ppm以下含有することがより好ましい。
On the other hand, when the content of the additive is excessively large, the degree of dissociation of ions in the entire non-aqueous electrolyte solution is excessively reduced, which is considered to hinder the flow of ions in the entire non-aqueous electrolyte secondary battery. Be done. Therefore, on the contrary, the battery characteristics such as the charge capacity after high rate discharge may be deteriorated. From the viewpoint of suppressing inhibition of ion flow in the entire non-aqueous electrolyte secondary battery, the non-aqueous electrolyte contains the additive in an amount of 300 ppm or less, preferably 250 ppm or less, and 180 ppm or less. Is more preferable.
ここで、本発明の一実施形態に係る非水電解液二次電池においては、充放電を繰り返した際、特に高速で電池を作動させた際における正極付近のイオンの解離度は、電解質近傍の添加剤の量に強く影響を受ける。
Here, in the non-aqueous electrolyte secondary battery according to the embodiment of the present invention, the degree of ion dissociation in the vicinity of the positive electrode during repeated charging and discharging, particularly when the battery is operated at a high speed, It is strongly influenced by the amount of additives.
従って、本発明の一実施形態に係る非水電解液二次電池は、非水電解液の種類に関係なく、正極付近のイオンの解離度を好適に小さくすることができる。すなわち、当該非水電解液に含まれる電解質の種類、量、および、含まれる有機溶媒の種類に関係なく、前記添加剤を0.5ppm以上、300ppm以下含有することにより、正極付近のイオンの解離度を好適に小さくすることができる。その結果、ハイレート放電後の充電容量の低下を抑制することができる。
Therefore, the nonaqueous electrolyte secondary battery according to the embodiment of the present invention can suitably reduce the degree of dissociation of ions near the positive electrode regardless of the type of the nonaqueous electrolyte. That is, regardless of the type and amount of the electrolyte contained in the non-aqueous electrolytic solution, and the type of the organic solvent contained, the addition of 0.5 ppm or more and 300 ppm or less of the additive causes dissociation of ions near the positive electrode. The degree can be suitably reduced. As a result, it is possible to suppress a decrease in charge capacity after high rate discharge.
前記非水電解液における添加剤の含有量を0.5ppm以上、300ppm以下に制御する方法は、特に限定されないが、例えば、後述する非水電解液二次電池の製造方法にて、非水電解液二次電池の筐体となる容器に注入する前記非水電解液に、前記添加剤を、その含有量が0.5ppm以上、300ppm以下となるように、前もって溶解させる方法等を挙げることができる。
The method for controlling the content of the additive in the non-aqueous electrolytic solution to be 0.5 ppm or more and 300 ppm or less is not particularly limited, but, for example, in the method for manufacturing a non-aqueous electrolytic solution secondary battery described later, non-aqueous electrolytic Examples include a method of pre-dissolving the additive in the non-aqueous electrolyte solution to be injected into the container that will be the housing of the liquid secondary battery, so that the content of the additive is 0.5 ppm or more and 300 ppm or less. it can.
[正極]
本発明の一実施形態における正極は、一般に非水電解液二次電池の正極として使用されるものであれば、特に限定されない。例えば、正極として、正極活物質および結着剤を含む活物質層が正極集電体上に成形された構造を備える正極シートを使用することができる。なお、前記活物質層は、更に導電剤を含んでもよい。 [Positive electrode]
The positive electrode in one embodiment of the present invention is not particularly limited as long as it is generally used as the positive electrode of a non-aqueous electrolyte secondary battery. For example, a positive electrode sheet having a structure in which an active material layer containing a positive electrode active material and a binder is formed on a positive electrode current collector can be used as the positive electrode. The active material layer may further contain a conductive agent.
本発明の一実施形態における正極は、一般に非水電解液二次電池の正極として使用されるものであれば、特に限定されない。例えば、正極として、正極活物質および結着剤を含む活物質層が正極集電体上に成形された構造を備える正極シートを使用することができる。なお、前記活物質層は、更に導電剤を含んでもよい。 [Positive electrode]
The positive electrode in one embodiment of the present invention is not particularly limited as long as it is generally used as the positive electrode of a non-aqueous electrolyte secondary battery. For example, a positive electrode sheet having a structure in which an active material layer containing a positive electrode active material and a binder is formed on a positive electrode current collector can be used as the positive electrode. The active material layer may further contain a conductive agent.
前記正極活物質としては、例えば、リチウムイオンまたはナトリウムイオン等の金属イオンをドープ・脱ドープ可能な材料が挙げられる。当該材料としては、具体的には、例えば、V、Mn、Fe、CoおよびNi等の遷移金属を少なくとも1種類含んでいるリチウム複合酸化物が挙げられる。
The positive electrode active material includes, for example, a material capable of being doped / dedoped with metal ions such as lithium ions or sodium ions. Specific examples of the material include a lithium composite oxide containing at least one transition metal such as V, Mn, Fe, Co, and Ni.
前記導電剤としては、例えば、天然黒鉛、人造黒鉛、コークス類、カーボンブラック、熱分解炭素類、炭素繊維および有機高分子化合物焼成体等の炭素質材料等が挙げられる。前記導電剤は、1種類のみを用いてもよく、2種類以上を組み合わせて用いてもよい。
Examples of the conductive agent include natural graphite, artificial graphite, cokes, carbon black, pyrolytic carbons, carbon fibers and carbonaceous materials such as organic polymer compound fired bodies. The conductive agent may be used alone or in combination of two or more kinds.
前記結着剤としては、例えば、ポリフッ化ビニリデン(PVDF)等のフッ素系樹脂、アクリル樹脂、スチレンブタジエンゴムが挙げられる。なお、結着剤は、増粘剤としての機能も有している。
Examples of the binder include fluororesin such as polyvinylidene fluoride (PVDF), acrylic resin, and styrene-butadiene rubber. The binder also has a function as a thickener.
前記正極集電体としては、例えば、Al、Niおよびステンレス等の導電体が挙げられる。中でも、薄膜に加工し易く、安価であることから、Alがより好ましい。
Examples of the positive electrode current collector include conductors such as Al, Ni and stainless steel. Among them, Al is more preferable because it is easily processed into a thin film and is inexpensive.
正極シートの製造方法としては、例えば、正極活物質、導電剤および結着剤を正極集電体上で加圧成型する方法;適当な有機溶剤を用いて正極活物質、導電剤および結着剤をペースト状にした後、当該ペーストを正極集電体に塗工し、乾燥した後に加圧して正極集電体に固着する方法;等が挙げられる。
The positive electrode sheet may be produced, for example, by pressure molding a positive electrode active material, a conductive agent and a binder on a positive electrode current collector; a positive electrode active material, a conductive agent and a binder using an appropriate organic solvent. Is applied to a positive electrode current collector, dried, and then pressed to fix it to the positive electrode current collector; and the like.
[負極]
本発明の一実施形態における負極としては、一般に非水電解液二次電池の負極として使用されるものであれば、特に限定されない。例えば、負極として、負極活物質および結着剤を含む活物質層が負極集電体上に成形された構造を備える負極シートを使用することができる。なお、前記活物質層は、更に導電剤を含んでもよい。 [Negative electrode]
The negative electrode in one embodiment of the present invention is not particularly limited as long as it is generally used as a negative electrode of a non-aqueous electrolyte secondary battery. For example, a negative electrode sheet having a structure in which an active material layer containing a negative electrode active material and a binder is formed on a negative electrode current collector can be used as the negative electrode. The active material layer may further contain a conductive agent.
本発明の一実施形態における負極としては、一般に非水電解液二次電池の負極として使用されるものであれば、特に限定されない。例えば、負極として、負極活物質および結着剤を含む活物質層が負極集電体上に成形された構造を備える負極シートを使用することができる。なお、前記活物質層は、更に導電剤を含んでもよい。 [Negative electrode]
The negative electrode in one embodiment of the present invention is not particularly limited as long as it is generally used as a negative electrode of a non-aqueous electrolyte secondary battery. For example, a negative electrode sheet having a structure in which an active material layer containing a negative electrode active material and a binder is formed on a negative electrode current collector can be used as the negative electrode. The active material layer may further contain a conductive agent.
前記負極活物質としては、例えば、リチウムイオンまたはナトリウムイオン等の金属イオンをドープ・脱ドープ可能な材料が挙げられる。当該材料としては、例えば、炭素質材料等が挙げられる。炭素質材料としては、天然黒鉛、人造黒鉛、コークス類、カーボンブラックおよび熱分解炭素類等が挙げられる。
As the negative electrode active material, for example, a material capable of doping / dedoping metal ions such as lithium ions or sodium ions can be mentioned. Examples of the material include a carbonaceous material and the like. Examples of the carbonaceous material include natural graphite, artificial graphite, cokes, carbon black and pyrolytic carbons.
前記負極集電体としては、例えば、Cu、Niおよびステンレス等が挙げられる。リチウムと合金を作り難く、かつ薄膜に加工し易いことから、Cuがより好ましい。
Examples of the negative electrode current collector include Cu, Ni and stainless steel. Cu is more preferable because it is difficult to form an alloy with lithium and is easily processed into a thin film.
負極シートの製造方法としては、例えば、負極活物質を負極集電体上で加圧成型する方法;適当な有機溶剤を用いて負極活物質をペースト状にした後、当該ペーストを負極集電体に塗工し、乾燥した後に加圧して負極集電体に固着する方法;等が挙げられる。前記ペーストには、好ましくは前記導電剤および前記結着剤が含まれる。
Examples of the method for producing the negative electrode sheet include a method in which the negative electrode active material is pressure-molded on the negative electrode current collector; the negative electrode active material is made into a paste using an appropriate organic solvent, and then the paste is used as the negative electrode current collector. And the like, and then pressurizing and fixing to the negative electrode current collector; and the like. The paste preferably contains the conductive agent and the binder.
[ポリオレフィン多孔質フィルム]
本発明の一実施形態における非水電解液二次電池は、ポリオレフィン多孔質フィルムを備えていてもよい。以下では、ポリオレフィン多孔質フィルムを単に「多孔質フィルム」と称することがある。前記多孔質フィルムは、ポリオレフィン系樹脂を主成分とし、その内部に連結した細孔を多数有しており、一方の面から他方の面に気体および液体を通過させることが可能となっている。前記多孔質フィルムは、単独で非水電解液二次電池用セパレータとなり得る。また、上述の多孔質層が積層された非水電解液二次電池用積層セパレータの基材ともなり得る。 [Polyolefin porous film]
The non-aqueous electrolyte secondary battery in one embodiment of the present invention may include a polyolefin porous film. Below, a polyolefin porous film may only be called a "porous film." The porous film contains a polyolefin-based resin as a main component and has a large number of pores connected to the inside thereof, so that a gas and a liquid can pass from one surface to the other surface. The porous film alone can serve as a separator for a non-aqueous electrolyte secondary battery. It can also be a base material of the laminated separator for a non-aqueous electrolyte secondary battery in which the above-mentioned porous layer is laminated.
本発明の一実施形態における非水電解液二次電池は、ポリオレフィン多孔質フィルムを備えていてもよい。以下では、ポリオレフィン多孔質フィルムを単に「多孔質フィルム」と称することがある。前記多孔質フィルムは、ポリオレフィン系樹脂を主成分とし、その内部に連結した細孔を多数有しており、一方の面から他方の面に気体および液体を通過させることが可能となっている。前記多孔質フィルムは、単独で非水電解液二次電池用セパレータとなり得る。また、上述の多孔質層が積層された非水電解液二次電池用積層セパレータの基材ともなり得る。 [Polyolefin porous film]
The non-aqueous electrolyte secondary battery in one embodiment of the present invention may include a polyolefin porous film. Below, a polyolefin porous film may only be called a "porous film." The porous film contains a polyolefin-based resin as a main component and has a large number of pores connected to the inside thereof, so that a gas and a liquid can pass from one surface to the other surface. The porous film alone can serve as a separator for a non-aqueous electrolyte secondary battery. It can also be a base material of the laminated separator for a non-aqueous electrolyte secondary battery in which the above-mentioned porous layer is laminated.
前記ポリオレフィン多孔質フィルムの少なくとも一方の面上に、前記多孔質層が積層されてなる積層体を、本明細書において、「非水電解液二次電池用積層セパレータ」または「積層セパレータ」とも称する。また、本発明の一実施形態における非水電解液二次電池用セパレータは、ポリオレフィン多孔質フィルムの他に、接着層、耐熱層、保護層等のその他の層をさらに備えていてもよい。
On at least one surface of the polyolefin porous film, a laminate in which the porous layer is laminated, in the present specification, also referred to as "non-aqueous electrolyte secondary battery laminated separator" or "laminated separator" .. Further, the separator for a non-aqueous electrolyte secondary battery in one embodiment of the present invention may further include other layers such as an adhesive layer, a heat resistant layer, and a protective layer, in addition to the polyolefin porous film.
多孔質フィルムに占めるポリオレフィンの割合は、多孔質フィルム全体の50体積%以上であり、90体積%以上であることがより好ましく、95体積%以上であることがさらに好ましい。また、前記ポリオレフィンには、重量平均分子量が5×105~15×106の高分子量成分が含まれていることがより好ましい。特に、ポリオレフィンに重量平均分子量が100万以上の高分子量成分が含まれていると、非水電解液二次電池用セパレータの強度が向上するのでより好ましい。
The proportion of polyolefin in the porous film is 50% by volume or more of the entire porous film, more preferably 90% by volume or more, and further preferably 95% by volume or more. Further, it is more preferable that the polyolefin contains a high molecular weight component having a weight average molecular weight of 5 × 10 5 to 15 × 10 6 . In particular, when the polyolefin contains a high molecular weight component having a weight average molecular weight of 1,000,000 or more, the strength of the separator for a non-aqueous electrolyte secondary battery is improved, which is more preferable.
熱可塑性樹脂である前記ポリオレフィンとしては、具体的には、例えば、エチレン、プロピレン、1-ブテン、4-メチル-1-ペンテンおよび1-ヘキセン等の単量体を重合してなる、単独重合体または共重合体が挙げられる。前記単独重合体としては、例えばポリエチレン、ポリプロピレン、ポリブテンを挙げることができる。また、前記共重合体としては、例えばエチレン-プロピレン共重合体を挙げることができる。
The polyolefin, which is a thermoplastic resin, is specifically a homopolymer obtained by polymerizing monomers such as ethylene, propylene, 1-butene, 4-methyl-1-pentene and 1-hexene. Alternatively, a copolymer may be used. Examples of the homopolymer include polyethylene, polypropylene and polybutene. Examples of the copolymer include ethylene-propylene copolymer.
このうち、過大電流が流れることをより低温で阻止することができるため、ポリエチレンがより好ましい。なお、この過大電流が流れることを阻止することをシャットダウンともいう。前記ポリエチレンとしては、低密度ポリエチレン、高密度ポリエチレン、線状ポリエチレン(エチレン-α-オレフィン共重合体)、重量平均分子量が100万以上の超高分子量ポリエチレン等が挙げられる。このうち、重量平均分子量が100万以上の超高分子量ポリエチレンがさらに好ましい。
Among these, polyethylene is more preferable because it can block excessive current from flowing at lower temperatures. Note that blocking the flow of this excessive current is also referred to as shutdown. Examples of the polyethylene include low density polyethylene, high density polyethylene, linear polyethylene (ethylene-α-olefin copolymer), and ultrahigh molecular weight polyethylene having a weight average molecular weight of 1,000,000 or more. Among these, ultrahigh molecular weight polyethylene having a weight average molecular weight of 1,000,000 or more is more preferable.
多孔質フィルムの膜厚は、4~40μmであることが好ましく、5~30μmであることがより好ましく、6~15μmであることがさらに好ましい。
The thickness of the porous film is preferably 4 to 40 μm, more preferably 5 to 30 μm, and further preferably 6 to 15 μm.
多孔質フィルムの単位面積当たりの目付は、強度、膜厚、重量およびハンドリング性を考慮して適宜決定することができる。ただし、非水電解液二次電池の重量エネルギー密度および体積エネルギー密度を高くすることができるように、前記目付は、4~20g/m2であることが好ましく、4~12g/m2であることがより好ましく、5~10g/m2であることがさらに好ましい。
The basis weight per unit area of the porous film can be appropriately determined in consideration of strength, film thickness, weight and handleability. However, the basis weight is preferably 4 to 20 g / m 2 , and preferably 4 to 12 g / m 2 so that the weight energy density and the volume energy density of the non-aqueous electrolyte secondary battery can be increased. More preferably, it is more preferably 5 to 10 g / m 2 .
多孔質フィルムの透気度は、ガーレ値で30~500sec/100mLであることが好ましく、50~300sec/100mLであることがより好ましい。多孔質フィルムが前記透気度を有することにより、充分なイオン透過性を得ることができる。多孔質フィルムに上述の多孔質層を積層させた非水電解液二次電池用積層セパレータの透気度は、ガーレ値で30~1000sec/100mLであることが好ましく、50~800sec/100mLであることがより好ましい。非水電解液二次電池用積層セパレータは、前記透気度を有することにより、非水電解液二次電池において、充分なイオン透過性を得ることができる。
The air permeability of the porous film is preferably 30 to 500 sec / 100 mL in Gurley value, and more preferably 50 to 300 sec / 100 mL. When the porous film has the above-mentioned air permeability, sufficient ion permeability can be obtained. The air permeability of the laminated separator for a non-aqueous electrolyte secondary battery in which the above-mentioned porous layer is laminated on the porous film is preferably 30 to 1000 sec / 100 mL in terms of Gurley value, and is 50 to 800 sec / 100 mL. Is more preferable. Since the laminated separator for a non-aqueous electrolyte secondary battery has the above-mentioned air permeability, it is possible to obtain sufficient ion permeability in the non-aqueous electrolyte secondary battery.
多孔質フィルムの空隙率は、電解液の保持量を高めると共に、過大電流が流れることをより低温で確実に阻止する機能を得ることができるように、20~80体積%であることが好ましく、30~75体積%であることがより好ましい。また、多孔質フィルムが有する細孔の孔径は、充分なイオン透過性を得ることができ、かつ、正極および負極への粒子の入り込みを防止することができるように、0.3μm以下であることが好ましく、0.14μm以下であることがより好ましい。
The porosity of the porous film is preferably 20 to 80% by volume so as to increase the holding amount of the electrolytic solution and to surely prevent the flow of an excessive current at a lower temperature. It is more preferably 30 to 75% by volume. The pore size of the pores of the porous film is 0.3 μm or less so that sufficient ion permeability can be obtained and particles can be prevented from entering the positive electrode and the negative electrode. Is preferable, and 0.14 μm or less is more preferable.
[ポリオレフィン多孔質フィルムの製造方法]
前記ポリオレフィン多孔質フィルムの製造方法は特に限定されるものではない。例えば、ポリオレフィン系樹脂と、無機充填剤および可塑剤等の孔形成剤と、任意で酸化防止剤等を混練した後に押し出すことで、シート状のポリオレフィン樹脂組成物を作製する。適当な溶媒にて当該孔形成剤を当該シート状のポリオレフィン樹脂組成物から除去した後、当該孔形成剤が除去されたポリオレフィン樹脂組成物を延伸することで、ポリオレフィン多孔質フィルムを製造することができる。 [Method for producing polyolefin porous film]
The method for producing the polyolefin porous film is not particularly limited. For example, a sheet-shaped polyolefin resin composition is prepared by kneading a polyolefin resin, a pore-forming agent such as an inorganic filler and a plasticizer, and optionally an antioxidant and the like and then extruding the kneaded product. After removing the pore-forming agent from the sheet-shaped polyolefin resin composition with an appropriate solvent, the polyolefin resin composition from which the pore-forming agent has been removed may be stretched to produce a polyolefin porous film. it can.
前記ポリオレフィン多孔質フィルムの製造方法は特に限定されるものではない。例えば、ポリオレフィン系樹脂と、無機充填剤および可塑剤等の孔形成剤と、任意で酸化防止剤等を混練した後に押し出すことで、シート状のポリオレフィン樹脂組成物を作製する。適当な溶媒にて当該孔形成剤を当該シート状のポリオレフィン樹脂組成物から除去した後、当該孔形成剤が除去されたポリオレフィン樹脂組成物を延伸することで、ポリオレフィン多孔質フィルムを製造することができる。 [Method for producing polyolefin porous film]
The method for producing the polyolefin porous film is not particularly limited. For example, a sheet-shaped polyolefin resin composition is prepared by kneading a polyolefin resin, a pore-forming agent such as an inorganic filler and a plasticizer, and optionally an antioxidant and the like and then extruding the kneaded product. After removing the pore-forming agent from the sheet-shaped polyolefin resin composition with an appropriate solvent, the polyolefin resin composition from which the pore-forming agent has been removed may be stretched to produce a polyolefin porous film. it can.
上記無機充填剤としては、特に限定されるものではなく、無機フィラー、具体的には炭酸カルシウム等が挙げられる。上記可塑剤としては、特に限定されるものではなく、流動パラフィン等の低分子量の炭化水素が挙げられる。
The above-mentioned inorganic filler is not particularly limited, and examples thereof include inorganic fillers, specifically calcium carbonate and the like. The plasticizer is not particularly limited, and examples thereof include low molecular weight hydrocarbons such as liquid paraffin.
具体的には、以下に示すような工程を含む方法を挙げることができる。
(A)超高分子量ポリエチレンと、重量平均分子量1万以下の低分子量ポリエチレンと、炭酸カルシウムまたは可塑剤等の孔形成剤と、酸化防止剤とを混練してポリオレフィン樹脂組成物を得る工程、
(B)得られたポリオレフィン樹脂組成物を一対の圧延ローラで圧延し、速度比を変えた巻き取りローラで引っ張りながら段階的に冷却し、シートを成形する工程、
(C)得られたシートの中から適当な溶媒にて孔形成剤を除去する工程、
(D)孔形成剤が除去されたシートを適当な延伸倍率にて延伸する工程。 Specifically, a method including the following steps can be mentioned.
(A) a step of kneading an ultrahigh molecular weight polyethylene, a low molecular weight polyethylene having a weight average molecular weight of 10,000 or less, a pore forming agent such as calcium carbonate or a plasticizer, and an antioxidant to obtain a polyolefin resin composition,
(B) a step of rolling the obtained polyolefin resin composition with a pair of rolling rollers and gradually cooling it while pulling it with a take-up roller having a different speed ratio to form a sheet,
(C) a step of removing the pore forming agent from the obtained sheet with a suitable solvent,
(D) A step of stretching the sheet from which the pore forming agent has been removed at an appropriate stretching ratio.
(A)超高分子量ポリエチレンと、重量平均分子量1万以下の低分子量ポリエチレンと、炭酸カルシウムまたは可塑剤等の孔形成剤と、酸化防止剤とを混練してポリオレフィン樹脂組成物を得る工程、
(B)得られたポリオレフィン樹脂組成物を一対の圧延ローラで圧延し、速度比を変えた巻き取りローラで引っ張りながら段階的に冷却し、シートを成形する工程、
(C)得られたシートの中から適当な溶媒にて孔形成剤を除去する工程、
(D)孔形成剤が除去されたシートを適当な延伸倍率にて延伸する工程。 Specifically, a method including the following steps can be mentioned.
(A) a step of kneading an ultrahigh molecular weight polyethylene, a low molecular weight polyethylene having a weight average molecular weight of 10,000 or less, a pore forming agent such as calcium carbonate or a plasticizer, and an antioxidant to obtain a polyolefin resin composition,
(B) a step of rolling the obtained polyolefin resin composition with a pair of rolling rollers and gradually cooling it while pulling it with a take-up roller having a different speed ratio to form a sheet,
(C) a step of removing the pore forming agent from the obtained sheet with a suitable solvent,
(D) A step of stretching the sheet from which the pore forming agent has been removed at an appropriate stretching ratio.
[非水電解液二次電池用積層セパレータの製造方法]
本発明の一実施形態における非水電解液二次電池用積層セパレータの製造方法としては、例えば、上述の「多孔質層の製造方法」において、前記塗工液を塗布する基材として、上述のポリオレフィン多孔質フィルムを使用する方法を挙げることができる。 [Method for producing laminated separator for non-aqueous electrolyte secondary battery]
Examples of the method for producing a laminated separator for a non-aqueous electrolyte secondary battery in one embodiment of the present invention include, for example, in the above-mentioned “method for producing a porous layer”, as the base material to which the coating liquid is applied, The method of using a polyolefin porous film can be mentioned.
本発明の一実施形態における非水電解液二次電池用積層セパレータの製造方法としては、例えば、上述の「多孔質層の製造方法」において、前記塗工液を塗布する基材として、上述のポリオレフィン多孔質フィルムを使用する方法を挙げることができる。 [Method for producing laminated separator for non-aqueous electrolyte secondary battery]
Examples of the method for producing a laminated separator for a non-aqueous electrolyte secondary battery in one embodiment of the present invention include, for example, in the above-mentioned “method for producing a porous layer”, as the base material to which the coating liquid is applied, The method of using a polyolefin porous film can be mentioned.
言い換えると、前記ポリオレフィン多孔質フィルムの片面または両面に前記多孔質層が積層されて非水電解液二次電池用積層セパレータが得られる。
In other words, the porous layer is laminated on one side or both sides of the polyolefin porous film to obtain a non-aqueous electrolyte secondary battery laminated separator.
[非水電解液二次電池の製造方法]
本発明の一実施形態に係る非水電解液二次電池の製造方法としては、従来公知の製造方法を採用することができる。例えば、正極、ポリオレフィン多孔質フィルムおよび負極をこの順で配置することにより非水電解液二次電池用部材を形成する。ここで、多孔質層は、ポリオレフィン多孔質フィルムと正極および負極の少なくとも一方との間に存在し得る。次いで、非水電解液二次電池の筐体となる容器に当該非水電解液二次電池用部材を入れる。当該容器内を前記非水電解液で満たした後、減圧しつつ密閉する。これにより、本発明の一実施形態に係る非水電解液二次電池を製造することができる。 [Method for producing non-aqueous electrolyte secondary battery]
As a method for manufacturing the non-aqueous electrolyte secondary battery according to the embodiment of the present invention, a conventionally known manufacturing method can be adopted. For example, by arranging the positive electrode, the polyolefin porous film, and the negative electrode in this order, a member for a non-aqueous electrolyte secondary battery is formed. Here, the porous layer may be present between the polyolefin porous film and at least one of the positive electrode and the negative electrode. Then, the member for a non-aqueous electrolyte secondary battery is put in a container which is a casing of the non-aqueous electrolyte secondary battery. After filling the inside of the container with the non-aqueous electrolyte, the container is sealed while reducing the pressure. Thereby, the non-aqueous electrolyte secondary battery according to the embodiment of the present invention can be manufactured.
本発明の一実施形態に係る非水電解液二次電池の製造方法としては、従来公知の製造方法を採用することができる。例えば、正極、ポリオレフィン多孔質フィルムおよび負極をこの順で配置することにより非水電解液二次電池用部材を形成する。ここで、多孔質層は、ポリオレフィン多孔質フィルムと正極および負極の少なくとも一方との間に存在し得る。次いで、非水電解液二次電池の筐体となる容器に当該非水電解液二次電池用部材を入れる。当該容器内を前記非水電解液で満たした後、減圧しつつ密閉する。これにより、本発明の一実施形態に係る非水電解液二次電池を製造することができる。 [Method for producing non-aqueous electrolyte secondary battery]
As a method for manufacturing the non-aqueous electrolyte secondary battery according to the embodiment of the present invention, a conventionally known manufacturing method can be adopted. For example, by arranging the positive electrode, the polyolefin porous film, and the negative electrode in this order, a member for a non-aqueous electrolyte secondary battery is formed. Here, the porous layer may be present between the polyolefin porous film and at least one of the positive electrode and the negative electrode. Then, the member for a non-aqueous electrolyte secondary battery is put in a container which is a casing of the non-aqueous electrolyte secondary battery. After filling the inside of the container with the non-aqueous electrolyte, the container is sealed while reducing the pressure. Thereby, the non-aqueous electrolyte secondary battery according to the embodiment of the present invention can be manufactured.
以下、実施例および比較例により、本発明をさらに詳細に説明するが、本発明はこれら実施例に限定されるものではない。
Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
[測定方法]
実施例および比較例にて製造された多孔質層、ポリオレフィン多孔質フィルムの物性等、並びに、非水電解液二次電池のハイレート放電後の充電容量を、以下の方法を用いて測定した。 [Measuring method]
The physical properties and the like of the porous layer and the polyolefin porous film produced in Examples and Comparative Examples, and the charge capacity after high rate discharge of the non-aqueous electrolyte secondary battery were measured using the following methods.
実施例および比較例にて製造された多孔質層、ポリオレフィン多孔質フィルムの物性等、並びに、非水電解液二次電池のハイレート放電後の充電容量を、以下の方法を用いて測定した。 [Measuring method]
The physical properties and the like of the porous layer and the polyolefin porous film produced in Examples and Comparative Examples, and the charge capacity after high rate discharge of the non-aqueous electrolyte secondary battery were measured using the following methods.
(1)膜厚(単位:μm)
ポリオレフィン多孔質フィルムおよび多孔質層の膜厚は、株式会社ミツトヨ製の高精度デジタル測長機(VL-50)を用いて測定した。多孔質層の膜厚は、各々の積層体において多孔質層が形成されている部分の膜厚から、多孔質層が形成されていない部分の膜厚を引いた値とした。 (1) Film thickness (unit: μm)
The thickness of the polyolefin porous film and the porous layer was measured using a high precision digital length measuring machine (VL-50) manufactured by Mitutoyo Corporation. The film thickness of the porous layer was a value obtained by subtracting the film thickness of the part where the porous layer was not formed from the film thickness of the part where the porous layer was formed in each laminate.
ポリオレフィン多孔質フィルムおよび多孔質層の膜厚は、株式会社ミツトヨ製の高精度デジタル測長機(VL-50)を用いて測定した。多孔質層の膜厚は、各々の積層体において多孔質層が形成されている部分の膜厚から、多孔質層が形成されていない部分の膜厚を引いた値とした。 (1) Film thickness (unit: μm)
The thickness of the polyolefin porous film and the porous layer was measured using a high precision digital length measuring machine (VL-50) manufactured by Mitutoyo Corporation. The film thickness of the porous layer was a value obtained by subtracting the film thickness of the part where the porous layer was not formed from the film thickness of the part where the porous layer was formed in each laminate.
(2)多孔質層表面の無機フィラーの投影像のアスペクト比の測定
実施例および比較例にて製造されたポリオレフィン多孔質フィルムと多孔質層とからなる積層体の多孔質層側から、日本電子製 電界放出形走査電子顕微鏡JSM-7600Fを用い、加速電圧5kVでSEM表面観察(反射電子像)を行い、電子顕微鏡写真(SEM画像)を得た。 (2) Measurement of Aspect Ratio of Projection Image of Inorganic Filler on Surface of Porous Layer From the porous layer side of the laminate comprising the polyolefin porous film and the porous layer produced in Examples and Comparative Examples, JEOL Ltd. Using a field emission scanning electron microscope JSM-7600F, SEM surface observation (backscattered electron image) was performed at an accelerating voltage of 5 kV to obtain an electron microscope photograph (SEM image).
実施例および比較例にて製造されたポリオレフィン多孔質フィルムと多孔質層とからなる積層体の多孔質層側から、日本電子製 電界放出形走査電子顕微鏡JSM-7600Fを用い、加速電圧5kVでSEM表面観察(反射電子像)を行い、電子顕微鏡写真(SEM画像)を得た。 (2) Measurement of Aspect Ratio of Projection Image of Inorganic Filler on Surface of Porous Layer From the porous layer side of the laminate comprising the polyolefin porous film and the porous layer produced in Examples and Comparative Examples, JEOL Ltd. Using a field emission scanning electron microscope JSM-7600F, SEM surface observation (backscattered electron image) was performed at an accelerating voltage of 5 kV to obtain an electron microscope photograph (SEM image).
得られたSEM画像上にOHPフィルムを載せ、無機フィラーの粒子の輪郭に沿って敷き写した投影像を作成し、該投影像をデジタルスチルカメラにより撮影した。得られた写真のデータをコンピュータに取り込み、アメリカ国立衛生研究所(NIH:National Institues of Health)が発行する画像解析のフリーソフトIMAGEJを用いて、粒子100個の各々のアスペクト比を算出した。ここでフィラー1粒子ずつを楕円形に近似させ、長軸径と短軸径を算出し、長軸径を短軸径で除した値をフィラー1個当たりのアスペクト比とした。その平均を多孔質層における多孔質層表面の無機フィラーの投影像のアスペクト比とした。以下、前記アスペクト比を、表面フィラーアスペクト比とも称する。
An OHP film was placed on the obtained SEM image to create a projected image laid out along the contours of the particles of the inorganic filler, and the projected image was taken by a digital still camera. The obtained photograph data was loaded into a computer, and the aspect ratio of each of 100 particles was calculated using free image analysis software IMAGEJ published by the National Institutes of Health (NIH). Here, each filler particle was approximated to an ellipse, the major axis diameter and the minor axis diameter were calculated, and the value obtained by dividing the major axis diameter by the minor axis diameter was taken as the aspect ratio per filler. The average was taken as the aspect ratio of the projected image of the inorganic filler on the surface of the porous layer in the porous layer. Hereinafter, the aspect ratio is also referred to as a surface filler aspect ratio.
(3)ピーク強度比の最大値の測定
実施例および比較例にて製造されたポリオレフィン多孔質フィルムと多孔質層とからなる積層体を2cm角に切り取り、測定用サンプルを得た。得られた測定用サンプルを、当該サンプルにおける多孔質層を測定面として、Al製ホルダーに取り付け広角X線回折法(2θ―θスキャン法)でX線プロファイルを測定した。装置として理学電機社製RU-200R(回転対陰極型)を使用し、X線源にCuKα線を用い、出力は50KV-200mA、スキャン速度2°/minにて測定した。得られたX線プロファイルに基づき、多孔質層の広角X線回折測定における、直交する任意の回折面(hkl)および(abc)のピーク強度 I(hkl)およびI(abc)が下式(1)を満たす場合の、I(hkl)/I(abc)で算出されるピーク強度比を算出し、そのピーク強度比の最大値を算出した。
I(hkl)> I(abc)・・・(1)。 (3) Measurement of maximum value of peak intensity ratio The laminate composed of the polyolefin porous film and the porous layer produced in Examples and Comparative Examples was cut into a 2 cm square to obtain a measurement sample. The obtained measurement sample was attached to an Al holder using the porous layer of the sample as a measurement surface, and the X-ray profile was measured by the wide-angle X-ray diffraction method (2θ-θ scan method). RU-200R (rotating anticathode type) manufactured by Rigaku Denki Co., Ltd. was used as an apparatus, CuKα rays were used as an X-ray source, and the output was measured at 50 KV-200 mA and a scan speed of 2 ° / min. Based on the obtained X-ray profile, the peak intensities I (hkl) and I (abc) of arbitrary diffraction planes (hkl) and (abc) orthogonal to each other in the wide-angle X-ray diffraction measurement of the porous layer are represented by the following formula (1 ). The peak intensity ratio calculated by I (hkl) / I (abc) in the case of satisfying (1) is calculated, and the maximum value of the peak intensity ratio is calculated.
I (hkl) > I (abc) ... (1).
実施例および比較例にて製造されたポリオレフィン多孔質フィルムと多孔質層とからなる積層体を2cm角に切り取り、測定用サンプルを得た。得られた測定用サンプルを、当該サンプルにおける多孔質層を測定面として、Al製ホルダーに取り付け広角X線回折法(2θ―θスキャン法)でX線プロファイルを測定した。装置として理学電機社製RU-200R(回転対陰極型)を使用し、X線源にCuKα線を用い、出力は50KV-200mA、スキャン速度2°/minにて測定した。得られたX線プロファイルに基づき、多孔質層の広角X線回折測定における、直交する任意の回折面(hkl)および(abc)のピーク強度 I(hkl)およびI(abc)が下式(1)を満たす場合の、I(hkl)/I(abc)で算出されるピーク強度比を算出し、そのピーク強度比の最大値を算出した。
I(hkl)> I(abc)・・・(1)。 (3) Measurement of maximum value of peak intensity ratio The laminate composed of the polyolefin porous film and the porous layer produced in Examples and Comparative Examples was cut into a 2 cm square to obtain a measurement sample. The obtained measurement sample was attached to an Al holder using the porous layer of the sample as a measurement surface, and the X-ray profile was measured by the wide-angle X-ray diffraction method (2θ-θ scan method). RU-200R (rotating anticathode type) manufactured by Rigaku Denki Co., Ltd. was used as an apparatus, CuKα rays were used as an X-ray source, and the output was measured at 50 KV-200 mA and a scan speed of 2 ° / min. Based on the obtained X-ray profile, the peak intensities I (hkl) and I (abc) of arbitrary diffraction planes (hkl) and (abc) orthogonal to each other in the wide-angle X-ray diffraction measurement of the porous layer are represented by the following formula (1 ). The peak intensity ratio calculated by I (hkl) / I (abc) in the case of satisfying (1) is calculated, and the maximum value of the peak intensity ratio is calculated.
I (hkl) > I (abc) ... (1).
(4)イオン電導度低下率(%)
エチレンカーボネート、エチルメチルカーボネートおよびジエチルカーボネートを3:5:2の体積比で混合してなる混合溶媒に、LiPF6をその濃度が1mol/Lとなるように溶解することにより、参照用電解液を得た。当該参照用電解液に、各添加剤を1%となるように添加して溶解した後、イオン電導度(mS/cm)を測定した。イオン電導度は株式会社堀場製作所製の電気伝導率計(ES-71)を用いて測定した。
イオン電導度低下率は、下記式(A)で表される。 (4) Reduction rate of ionic conductivity (%)
LiPF 6 was dissolved in a mixed solvent prepared by mixing ethylene carbonate, ethylmethyl carbonate and diethyl carbonate in a volume ratio of 3: 5: 2 to a concentration of 1 mol / L to prepare a reference electrolyte solution. Obtained. Each additive was added to the reference electrolyte solution to be 1% and dissolved, and then the ionic conductivity (mS / cm) was measured. The ionic conductivity was measured using an electric conductivity meter (ES-71) manufactured by Horiba Ltd.
The ionic conductivity decrease rate is represented by the following formula (A).
エチレンカーボネート、エチルメチルカーボネートおよびジエチルカーボネートを3:5:2の体積比で混合してなる混合溶媒に、LiPF6をその濃度が1mol/Lとなるように溶解することにより、参照用電解液を得た。当該参照用電解液に、各添加剤を1%となるように添加して溶解した後、イオン電導度(mS/cm)を測定した。イオン電導度は株式会社堀場製作所製の電気伝導率計(ES-71)を用いて測定した。
イオン電導度低下率は、下記式(A)で表される。 (4) Reduction rate of ionic conductivity (%)
LiPF 6 was dissolved in a mixed solvent prepared by mixing ethylene carbonate, ethylmethyl carbonate and diethyl carbonate in a volume ratio of 3: 5: 2 to a concentration of 1 mol / L to prepare a reference electrolyte solution. Obtained. Each additive was added to the reference electrolyte solution to be 1% and dissolved, and then the ionic conductivity (mS / cm) was measured. The ionic conductivity was measured using an electric conductivity meter (ES-71) manufactured by Horiba Ltd.
The ionic conductivity decrease rate is represented by the following formula (A).
L=(LA-LB)/LA・・・(A)
L:イオン電導度低下率(%)、
LA:添加する前のイオン電導度(mS/cm)、
LB:添加後のイオン電導度(mS/cm)。 L = (LA-LB) / LA ... (A)
L: reduction rate of ionic conductivity (%),
LA: ionic conductivity (mS / cm) before addition,
LB: Ionic conductivity (mS / cm) after addition.
L:イオン電導度低下率(%)、
LA:添加する前のイオン電導度(mS/cm)、
LB:添加後のイオン電導度(mS/cm)。 L = (LA-LB) / LA ... (A)
L: reduction rate of ionic conductivity (%),
LA: ionic conductivity (mS / cm) before addition,
LB: Ionic conductivity (mS / cm) after addition.
(5)非水電解液二次電池の電池特性
後述のようにして組み立てた非水電解液二次電池を、25℃で電圧範囲;4.1~2.7V、充電電流値;0.2CのCC-CV充電(終止電流条件0.02C)、放電電流値0.2CのCC放電を1サイクルとして、4サイクルの初期充放電を25℃にて実施した。 (5) Battery Characteristics of Non-Aqueous Electrolyte Secondary Battery A non-aqueous electrolyte secondary battery assembled as described below was operated at 25 ° C. in a voltage range of 4.1 to 2.7 V and a charging current value of 0.2 C. The CC-CV charging (final current condition 0.02C) and the CC discharging having a discharge current value of 0.2C were set as one cycle, and the initial charge / discharge for four cycles was performed at 25 ° C.
後述のようにして組み立てた非水電解液二次電池を、25℃で電圧範囲;4.1~2.7V、充電電流値;0.2CのCC-CV充電(終止電流条件0.02C)、放電電流値0.2CのCC放電を1サイクルとして、4サイクルの初期充放電を25℃にて実施した。 (5) Battery Characteristics of Non-Aqueous Electrolyte Secondary Battery A non-aqueous electrolyte secondary battery assembled as described below was operated at 25 ° C. in a voltage range of 4.1 to 2.7 V and a charging current value of 0.2 C. The CC-CV charging (final current condition 0.02C) and the CC discharging having a discharge current value of 0.2C were set as one cycle, and the initial charge / discharge for four cycles was performed at 25 ° C.
なお、1時間率の放電容量による定格容量を1時間で放電する電流値を1Cとする。また、CC-CV充電とは、設定した一定の電流で充電し、所定の電圧に到達後、電流を絞りながら、その電圧を維持する充電方法である。CC放電とは、設定した一定の電流で所定の電圧まで放電する方法である。これらは以下も同様である。
Note that the current value for discharging the rated capacity based on the discharge capacity of 1 hour rate in 1 hour is 1C. CC-CV charging is a charging method in which charging is performed with a set constant current, and after reaching a predetermined voltage, the current is reduced while maintaining the voltage. CC discharge is a method of discharging to a predetermined voltage with a set constant current. The same applies to the following.
前記初期充放電を行った非水電解液二次電池に対して、充電電流値1CのCC-CV充電(終止電流条件0.02C)、放電電流値0.2C、1C、3Cの順によりCC放電を実施した。各レートにつき充放電を3サイクル、55℃にて実施した。このとき、電圧範囲は2.7V~4.2Vとした。このとき、3C放電レート特性測定時の3サイクル目の1C充電のときの充電容量を測定し、ハイレート放電後の充電容量とした。なお、実施例、比較例にて製造した非水電解液二次電池の設計容量は、20.5mAhであった。
CC-CV charging with a charging current value of 1C (end current condition 0.02C), discharging current values of 0.2C, 1C, and 3C were applied to the non-aqueous electrolyte secondary battery subjected to the initial charge / discharge in the order of CC. A discharge was performed. Charging / discharging was performed for 3 cycles at 55 ° C. for each rate. At this time, the voltage range was set to 2.7V to 4.2V. At this time, the charge capacity at the time of 1C charge in the third cycle at the time of measuring the 3C discharge rate characteristic was measured and taken as the charge capacity after high rate discharge. The designed capacity of the non-aqueous electrolyte secondary batteries manufactured in Examples and Comparative Examples was 20.5 mAh.
[実施例1]
[非水電解液二次電池用セパレータの製造]
ポリエチレンを用いて非水電解液二次電池用セパレータを作製した。具体的には、超高分子量ポリエチレン粉末(340M、三井化学株式会社製)70重量部と、重量平均分子量1000のポリエチレンワックス(FNP-0115、日本精鑞株式会社製)30重量部とを混合して混合ポリエチレンを得た。得られた混合ポリエチレン100重量部に対して、酸化防止剤(Irg1010、チバ・スペシャリティ・ケミカルズ株式会社製)0.4重量部、酸化防止剤(P168、チバ・スペシャリティ・ケミカルズ株式会社製)0.1重量部、およびステアリン酸ナトリウム1.3重量部を加え、さらに、全体積に占める割合が38体積%となるように、平均粒子径0.1μmの炭酸カルシウム(丸尾カルシウム株式会社製)を加えた。この組成物を粉末のまま、ヘンシェルミキサーで混合した後、二軸混練機で溶融混練することにより、ポリエチレン樹脂組成物を得た。次いで、このポリエチレン樹脂組成物を、表面温度が150℃に設定された一対のローラにて圧延することにより、シートを作製した。このシートを、4mol/Lの塩酸に0.5重量%の非イオン系界面活性剤を配合して調製した塩酸水溶液に浸漬させることで炭酸カルシウムを溶解して除去した。続いて、当該シートを105℃で6倍に延伸することにより、ポリオレフィン多孔質フィルムを作製した。ポリオレフィン多孔質フィルムの空隙率53%、目付7g/m2、膜厚16μmであった。このポリオレフィン多孔質フィルムを、非水電解液二次電池用セパレータ1とした。 [Example 1]
[Manufacture of separator for non-aqueous electrolyte secondary battery]
A separator for a non-aqueous electrolyte secondary battery was produced using polyethylene. Specifically, 70 parts by weight of ultra high molecular weight polyethylene powder (340M, manufactured by Mitsui Chemicals, Inc.) and 30 parts by weight of polyethylene wax having a weight average molecular weight of 1000 (FNP-0115, manufactured by Nippon Seiro Co., Ltd.) are mixed. To obtain mixed polyethylene. With respect to 100 parts by weight of the obtained mixed polyethylene, 0.4 parts by weight of an antioxidant (Irg1010, manufactured by Ciba Specialty Chemicals Co., Ltd.), and an antioxidant (P168, manufactured by Ciba Specialty Chemicals Co., Ltd.) 0. 1 part by weight and 1.3 parts by weight of sodium stearate were added, and further, calcium carbonate having an average particle size of 0.1 μm (manufactured by Maruo Calcium Co., Ltd.) was added so that the ratio of the total volume was 38% by volume. It was This composition as a powder was mixed with a Henschel mixer and then melt-kneaded with a biaxial kneader to obtain a polyethylene resin composition. Then, this polyethylene resin composition was rolled by a pair of rollers whose surface temperature was set to 150 ° C. to prepare a sheet. This sheet was immersed in an aqueous hydrochloric acid solution prepared by mixing 0.5 mol% of a nonionic surfactant in 4 mol / L hydrochloric acid to dissolve and remove calcium carbonate. Then, the said sheet | seat was stretched 6 times at 105 degreeC, and the polyolefin porous film was produced. The porosity of the polyolefin porous film was 53%, the basis weight was 7 g / m 2 , and the film thickness was 16 μm. This polyolefin porous film was used as a separator 1 for a non-aqueous electrolyte secondary battery.
[非水電解液二次電池用セパレータの製造]
ポリエチレンを用いて非水電解液二次電池用セパレータを作製した。具体的には、超高分子量ポリエチレン粉末(340M、三井化学株式会社製)70重量部と、重量平均分子量1000のポリエチレンワックス(FNP-0115、日本精鑞株式会社製)30重量部とを混合して混合ポリエチレンを得た。得られた混合ポリエチレン100重量部に対して、酸化防止剤(Irg1010、チバ・スペシャリティ・ケミカルズ株式会社製)0.4重量部、酸化防止剤(P168、チバ・スペシャリティ・ケミカルズ株式会社製)0.1重量部、およびステアリン酸ナトリウム1.3重量部を加え、さらに、全体積に占める割合が38体積%となるように、平均粒子径0.1μmの炭酸カルシウム(丸尾カルシウム株式会社製)を加えた。この組成物を粉末のまま、ヘンシェルミキサーで混合した後、二軸混練機で溶融混練することにより、ポリエチレン樹脂組成物を得た。次いで、このポリエチレン樹脂組成物を、表面温度が150℃に設定された一対のローラにて圧延することにより、シートを作製した。このシートを、4mol/Lの塩酸に0.5重量%の非イオン系界面活性剤を配合して調製した塩酸水溶液に浸漬させることで炭酸カルシウムを溶解して除去した。続いて、当該シートを105℃で6倍に延伸することにより、ポリオレフィン多孔質フィルムを作製した。ポリオレフィン多孔質フィルムの空隙率53%、目付7g/m2、膜厚16μmであった。このポリオレフィン多孔質フィルムを、非水電解液二次電池用セパレータ1とした。 [Example 1]
[Manufacture of separator for non-aqueous electrolyte secondary battery]
A separator for a non-aqueous electrolyte secondary battery was produced using polyethylene. Specifically, 70 parts by weight of ultra high molecular weight polyethylene powder (340M, manufactured by Mitsui Chemicals, Inc.) and 30 parts by weight of polyethylene wax having a weight average molecular weight of 1000 (FNP-0115, manufactured by Nippon Seiro Co., Ltd.) are mixed. To obtain mixed polyethylene. With respect to 100 parts by weight of the obtained mixed polyethylene, 0.4 parts by weight of an antioxidant (Irg1010, manufactured by Ciba Specialty Chemicals Co., Ltd.), and an antioxidant (P168, manufactured by Ciba Specialty Chemicals Co., Ltd.) 0. 1 part by weight and 1.3 parts by weight of sodium stearate were added, and further, calcium carbonate having an average particle size of 0.1 μm (manufactured by Maruo Calcium Co., Ltd.) was added so that the ratio of the total volume was 38% by volume. It was This composition as a powder was mixed with a Henschel mixer and then melt-kneaded with a biaxial kneader to obtain a polyethylene resin composition. Then, this polyethylene resin composition was rolled by a pair of rollers whose surface temperature was set to 150 ° C. to prepare a sheet. This sheet was immersed in an aqueous hydrochloric acid solution prepared by mixing 0.5 mol% of a nonionic surfactant in 4 mol / L hydrochloric acid to dissolve and remove calcium carbonate. Then, the said sheet | seat was stretched 6 times at 105 degreeC, and the polyolefin porous film was produced. The porosity of the polyolefin porous film was 53%, the basis weight was 7 g / m 2 , and the film thickness was 16 μm. This polyolefin porous film was used as a separator 1 for a non-aqueous electrolyte secondary battery.
[多孔質層の製造]
(塗工液の製造)
無機フィラーの原料として、αアルミナ(住友化学株式会社製、商品名:AKP3000)および六角板状酸化亜鉛(堺化学工業株式会社製、商品名:XZ-100F)を用い、無機フィラーとして、αアルミナ99重量部と、六角板状酸化亜鉛1重量部とを、乳鉢で混合した混合物(酸素原子質量百分率47%)を用いた。 [Production of porous layer]
(Production of coating liquid)
Α-alumina (Sumitomo Chemical Co., Ltd., trade name: AKP3000) and hexagonal plate-shaped zinc oxide (Sakai Chemical Industry Co., Ltd., trade name: XZ-100F) were used as raw materials for the inorganic filler, and α-alumina was used as the inorganic filler. A mixture (oxygen atomic mass percentage 47%) in which 99 parts by weight and 1 part by weight of hexagonal zinc oxide were mixed in a mortar was used.
(塗工液の製造)
無機フィラーの原料として、αアルミナ(住友化学株式会社製、商品名:AKP3000)および六角板状酸化亜鉛(堺化学工業株式会社製、商品名:XZ-100F)を用い、無機フィラーとして、αアルミナ99重量部と、六角板状酸化亜鉛1重量部とを、乳鉢で混合した混合物(酸素原子質量百分率47%)を用いた。 [Production of porous layer]
(Production of coating liquid)
Α-alumina (Sumitomo Chemical Co., Ltd., trade name: AKP3000) and hexagonal plate-shaped zinc oxide (Sakai Chemical Industry Co., Ltd., trade name: XZ-100F) were used as raw materials for the inorganic filler, and α-alumina was used as the inorganic filler. A mixture (oxygen atomic mass percentage 47%) in which 99 parts by weight and 1 part by weight of hexagonal zinc oxide were mixed in a mortar was used.
無機フィラーの体積基準の粒度分布の算出は、島津製作所製 レーザー回折式粒度分布計SALD2200を使用してD10、D50、D90を測定することにより行った。ここで体積基準による積算分布が50%になる値の粒子径、10%になる値の粒子径、90%になる値の粒子径を、それぞれD50、D10、D90と称する。
The volume-based particle size distribution of the inorganic filler was calculated by measuring D10, D50 and D90 using a laser diffraction particle size distribution analyzer SALD2200 manufactured by Shimadzu Corporation. The particle diameter at which the cumulative distribution based on volume is 50%, the particle diameter at 10%, and the particle diameter at 90% are referred to as D50, D10, and D90, respectively.
また、フィラーの比表面積は、定容法を用いて、窒素による吸着脱離等温線を測定し、BET法から算出した。
The specific surface area of the filler was calculated from the BET method by measuring the adsorption-desorption isotherm with nitrogen using the constant volume method.
前記樹脂として、フッ化ビニリデン-ヘキサフルオロプロピレン共重合体(アルケマ株式会社製;商品名「KYNAR2801」)を用いた。
As the resin, a vinylidene fluoride-hexafluoropropylene copolymer (manufactured by Arkema Ltd .; trade name “KYNAR2801”) was used.
前記無機フィラー、フッ化ビニリデン-ヘキサフルオロプロピレン共重合体および溶媒(関東化学株式会社製 N-メチル‐2-ピロリジノン)を、下記割合となるように混合した。すなわち無機フィラー90重量部に対してフッ化ビニリデン-ヘキサフルオロプロピレン共重合体10重量部を混合した後、得られる混合液における、無機フィラーおよびフッ化ビニリデン-ヘキサフルオロプロピレン共重合体からなる固形分の濃度が40重量%となるように溶媒を混合して混合液を作製した。得られた混合液を薄膜旋回型高速ミキサー(プライミクス(株)製フィルミク(登録商標))で攪拌および混合して均一な塗工液を得た。
The inorganic filler, vinylidene fluoride-hexafluoropropylene copolymer and solvent (N-methyl-2-pyrrolidinone manufactured by Kanto Chemical Co., Inc.) were mixed in the following proportions. That is, after mixing 10 parts by weight of vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of inorganic filler, the solid content of the inorganic filler and vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid. A solvent was mixed so that the concentration of the above was 40% by weight to prepare a mixed solution. The obtained mixed liquid was stirred and mixed with a thin film swivel type high speed mixer (Filmiku (registered trademark) manufactured by Primix Co., Ltd.) to obtain a uniform coating liquid.
(多孔質層の製造)
得られた前記塗工液を、前記非水電解液二次電池用セパレータ1の片面にドクターブレード法により、塗工せん断速度39.4(1/s)にて塗工し、前記非水電解液二次電池用セパレータ1の片面に塗膜を形成した。その後、前記塗膜を、65℃にて20分間かけて乾燥することで、前記非水電解液二次電池用セパレータ1の片面に多孔質層1を形成した。これにより非水電解液二次電池用セパレータ1と多孔質層1とを備えた積層体1を得た。多孔質層1の目付は7g/m2であり、厚みは4μmであった。得られた積層体1を用いて、多孔質層表面の無機フィラーの投影像のアスペクト比およびピーク強度比(I(hkl)/I(abc))の最大値を測定した。その結果を表1に示す。 (Production of porous layer)
The obtained coating liquid was applied to one side of the separator 1 for non-aqueous electrolyte secondary battery by a doctor blade method at a coating shear rate of 39.4 (1 / s), and the non-aqueous electrolysis was performed. A coating film was formed on one surface of the liquid secondary battery separator 1. Then, the coating film was dried at 65 ° C. for 20 minutes to form the porous layer 1 on one surface of the separator 1 for non-aqueous electrolyte secondary battery. As a result, a laminate 1 including the separator 1 for non-aqueous electrolyte secondary battery and the porous layer 1 was obtained. The basis weight of the porous layer 1 was 7 g / m 2 and the thickness was 4 μm. Using the obtained laminate 1, the maximum values of the aspect ratio and peak intensity ratio (I (hkl) / I (abc) ) of the projected image of the inorganic filler on the surface of the porous layer were measured. The results are shown in Table 1.
得られた前記塗工液を、前記非水電解液二次電池用セパレータ1の片面にドクターブレード法により、塗工せん断速度39.4(1/s)にて塗工し、前記非水電解液二次電池用セパレータ1の片面に塗膜を形成した。その後、前記塗膜を、65℃にて20分間かけて乾燥することで、前記非水電解液二次電池用セパレータ1の片面に多孔質層1を形成した。これにより非水電解液二次電池用セパレータ1と多孔質層1とを備えた積層体1を得た。多孔質層1の目付は7g/m2であり、厚みは4μmであった。得られた積層体1を用いて、多孔質層表面の無機フィラーの投影像のアスペクト比およびピーク強度比(I(hkl)/I(abc))の最大値を測定した。その結果を表1に示す。 (Production of porous layer)
The obtained coating liquid was applied to one side of the separator 1 for non-aqueous electrolyte secondary battery by a doctor blade method at a coating shear rate of 39.4 (1 / s), and the non-aqueous electrolysis was performed. A coating film was formed on one surface of the liquid secondary battery separator 1. Then, the coating film was dried at 65 ° C. for 20 minutes to form the porous layer 1 on one surface of the separator 1 for non-aqueous electrolyte secondary battery. As a result, a laminate 1 including the separator 1 for non-aqueous electrolyte secondary battery and the porous layer 1 was obtained. The basis weight of the porous layer 1 was 7 g / m 2 and the thickness was 4 μm. Using the obtained laminate 1, the maximum values of the aspect ratio and peak intensity ratio (I (hkl) / I (abc) ) of the projected image of the inorganic filler on the surface of the porous layer were measured. The results are shown in Table 1.
[非水電解液二次電池の作製]
(正極の作製)
LiNi0.5Mn0.3Co0.2O2/導電剤/PVDF(重量比92/5/3)をアルミニウム箔に塗布することにより製造された市販の正極を用いた。前記市販の正極を、正極活物質層が形成された部分の大きさが40mm×35mmであり、かつその外周に幅13mmで正極活物質層が形成されていない部分が残るように、アルミニウム箔を切り取って正極とした。正極活物質層の厚さは58μm、密度は2.50g/cm3であった。 [Preparation of non-aqueous electrolyte secondary battery]
(Preparation of positive electrode)
A commercially available positive electrode manufactured by applying LiNi 0.5 Mn 0.3 Co 0.2 O 2 / conductive agent / PVDF (weight ratio 92/5/3) to an aluminum foil was used. An aluminum foil was applied to the commercially available positive electrode so that the size of the part where the positive electrode active material layer was formed was 40 mm × 35 mm, and the part where the width of 13 mm was not formed and the positive electrode active material layer was not formed remained on the outer periphery thereof. It was cut out to obtain a positive electrode. The positive electrode active material layer had a thickness of 58 μm and a density of 2.50 g / cm 3 .
(正極の作製)
LiNi0.5Mn0.3Co0.2O2/導電剤/PVDF(重量比92/5/3)をアルミニウム箔に塗布することにより製造された市販の正極を用いた。前記市販の正極を、正極活物質層が形成された部分の大きさが40mm×35mmであり、かつその外周に幅13mmで正極活物質層が形成されていない部分が残るように、アルミニウム箔を切り取って正極とした。正極活物質層の厚さは58μm、密度は2.50g/cm3であった。 [Preparation of non-aqueous electrolyte secondary battery]
(Preparation of positive electrode)
A commercially available positive electrode manufactured by applying LiNi 0.5 Mn 0.3 Co 0.2 O 2 / conductive agent / PVDF (weight ratio 92/5/3) to an aluminum foil was used. An aluminum foil was applied to the commercially available positive electrode so that the size of the part where the positive electrode active material layer was formed was 40 mm × 35 mm, and the part where the width of 13 mm was not formed and the positive electrode active material layer was not formed remained on the outer periphery thereof. It was cut out to obtain a positive electrode. The positive electrode active material layer had a thickness of 58 μm and a density of 2.50 g / cm 3 .
(負極の作製)
黒鉛/スチレン-1,3-ブタジエン共重合体/カルボキシメチルセルロースナトリウム(重量比98/1/1)を銅箔に塗布することにより製造された市販の負極を用いた。前記市販の負極を、負極活物質層が形成された部分の大きさが50mm×40mmであり、かつその外周に幅13mmで負極活物質層が形成されていない部分が残るように、銅箔を切り取って負極とした。負極活物質層の厚さは49μm、の密度は1.40g/cm3であった。 (Preparation of negative electrode)
A commercially available negative electrode manufactured by applying graphite / styrene-1,3-butadiene copolymer / sodium carboxymethyl cellulose (weight ratio 98/1/1) to a copper foil was used. A copper foil was applied to the commercially available negative electrode so that the size of the part where the negative electrode active material layer was formed was 50 mm × 40 mm, and the part where the width of 13 mm was not formed and the negative electrode active material layer was not formed remained on the outer periphery thereof. It was cut out to obtain a negative electrode. The negative electrode active material layer had a thickness of 49 μm and a density of 1.40 g / cm 3 .
黒鉛/スチレン-1,3-ブタジエン共重合体/カルボキシメチルセルロースナトリウム(重量比98/1/1)を銅箔に塗布することにより製造された市販の負極を用いた。前記市販の負極を、負極活物質層が形成された部分の大きさが50mm×40mmであり、かつその外周に幅13mmで負極活物質層が形成されていない部分が残るように、銅箔を切り取って負極とした。負極活物質層の厚さは49μm、の密度は1.40g/cm3であった。 (Preparation of negative electrode)
A commercially available negative electrode manufactured by applying graphite / styrene-1,3-butadiene copolymer / sodium carboxymethyl cellulose (weight ratio 98/1/1) to a copper foil was used. A copper foil was applied to the commercially available negative electrode so that the size of the part where the negative electrode active material layer was formed was 50 mm × 40 mm, and the part where the width of 13 mm was not formed and the negative electrode active material layer was not formed remained on the outer periphery thereof. It was cut out to obtain a negative electrode. The negative electrode active material layer had a thickness of 49 μm and a density of 1.40 g / cm 3 .
(非水電解液の作製)
エチレンカーボネート、エチルメチルカーボネート、ジエチルカーボネートを3:5:2の体積比で混合した混合溶媒に、LiPF6をその濃度が1mol/Lとなるように溶解して、電解液原液1とした。この電解液原液1はLi+イオンを含む非プロトン性極性溶媒電解液である。 (Preparation of non-aqueous electrolyte)
LiPF 6 was dissolved in a mixed solvent in which ethylene carbonate, ethylmethyl carbonate, and diethyl carbonate were mixed at a volume ratio of 3: 5: 2 so that the concentration thereof was 1 mol / L, to prepare an electrolytic solution stock solution 1. This electrolytic solution stock solution 1 is an aprotic polar solvent electrolytic solution containing Li + ions.
エチレンカーボネート、エチルメチルカーボネート、ジエチルカーボネートを3:5:2の体積比で混合した混合溶媒に、LiPF6をその濃度が1mol/Lとなるように溶解して、電解液原液1とした。この電解液原液1はLi+イオンを含む非プロトン性極性溶媒電解液である。 (Preparation of non-aqueous electrolyte)
LiPF 6 was dissolved in a mixed solvent in which ethylene carbonate, ethylmethyl carbonate, and diethyl carbonate were mixed at a volume ratio of 3: 5: 2 so that the concentration thereof was 1 mol / L, to prepare an electrolytic solution stock solution 1. This electrolytic solution stock solution 1 is an aprotic polar solvent electrolytic solution containing Li + ions.
ジブチルヒドロキシトルエン(BHT、イオン電導度低下率:5.3%)10.3mgにジエチルカーボネートを加えて溶かして5mLとし、添加液1とした。300μLの添加液1と1700μLの電解液原液1とを混合し、非水電解液1とした。非水電解液1における添加剤の含有量を表2に示す。
Addition liquid 1 was prepared by adding diethyl carbonate to 10.3 mg of dibutylhydroxytoluene (BHT, ionic conductivity reduction rate: 5.3%) to make a volume of 5 mL. A non-aqueous electrolyte solution 1 was prepared by mixing 300 μL of the additive solution 1 and 1700 μL of the electrolyte solution stock solution 1. Table 2 shows the content of the additive in the non-aqueous electrolyte solution 1.
(非水電解液二次電池の組み立て)
前記正極、前記負極および積層体1および非水電解液1を使用して、以下に示す方法にて非水電解液二次電池を製造した。製造した非水電解液二次電池を非水電解液二次電池1とした。 (Assembly of non-aqueous electrolyte secondary battery)
A non-aqueous electrolyte secondary battery was manufactured by the following method using the positive electrode, the negative electrode, the laminate 1, and the non-aqueous electrolyte solution 1. The produced non-aqueous electrolyte secondary battery was designated as non-aqueous electrolyte secondary battery 1.
前記正極、前記負極および積層体1および非水電解液1を使用して、以下に示す方法にて非水電解液二次電池を製造した。製造した非水電解液二次電池を非水電解液二次電池1とした。 (Assembly of non-aqueous electrolyte secondary battery)
A non-aqueous electrolyte secondary battery was manufactured by the following method using the positive electrode, the negative electrode, the laminate 1, and the non-aqueous electrolyte solution 1. The produced non-aqueous electrolyte secondary battery was designated as non-aqueous electrolyte secondary battery 1.
ラミネートパウチ内で、前記正極、多孔質層を正極側に対向させた積層体1、および負極をこの順で積層することにより、非水電解液二次電池用部材1を得た。このとき、正極の正極活物質層における主面の全部が、負極の負極活物質層における主面の範囲に含まれるように、正極および負極を配置した。すなわち、正極の正極活物質層における主面の全部が、負極の負極活物質層における主面に重なるように、正極および負極を配置した。
A non-aqueous electrolyte secondary battery member 1 was obtained by stacking the positive electrode, the laminate 1 with the porous layer facing the positive electrode side, and the negative electrode in this order in a laminate pouch. At this time, the positive electrode and the negative electrode were arranged such that the entire main surface of the positive electrode active material layer of the positive electrode was included in the range of the main surface of the negative electrode active material layer of the negative electrode. That is, the positive electrode and the negative electrode were arranged such that the entire main surface of the positive electrode active material layer of the positive electrode overlaps the main surface of the negative electrode active material layer of the negative electrode.
続いて、非水電解液二次電池用部材1を、予め作製していた、アルミニウム層とヒートシール層とが積層されてなる袋に入れ、さらにこの袋に非水電解液1を0.23mL入れた。そして、袋内を減圧しつつ、当該袋をヒートシールすることにより、非水電解液二次電池1を作製した。
Subsequently, the non-aqueous electrolyte secondary battery member 1 was placed in a previously prepared bag in which an aluminum layer and a heat seal layer were laminated, and 0.23 mL of the non-aqueous electrolyte solution 1 was further placed in this bag. I put it in. Then, the inside of the bag was depressurized and the bag was heat-sealed to manufacture the non-aqueous electrolyte secondary battery 1.
その後、上述の方法にて得られた非水電解液二次電池1のハイレート放電後の充電容量の測定を行った。その結果を表2に示す。
After that, the charge capacity of the non-aqueous electrolyte secondary battery 1 obtained by the above method after high rate discharge was measured. The results are shown in Table 2.
[実施例2]
[非水電解液二次電池の作製]
(非水電解液の作製)
エチレンカーボネート、ジエチルカーボネートを3:7の体積比で混合した混合溶媒に、LiPF6をその濃度が1mol/Lとなるように溶解して、電解液原液2とした。 [Example 2]
[Preparation of non-aqueous electrolyte secondary battery]
(Preparation of non-aqueous electrolyte)
LiPF 6 was dissolved in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 3: 7 so that the concentration thereof was 1 mol / L, to prepare an electrolyte solution stock solution 2.
[非水電解液二次電池の作製]
(非水電解液の作製)
エチレンカーボネート、ジエチルカーボネートを3:7の体積比で混合した混合溶媒に、LiPF6をその濃度が1mol/Lとなるように溶解して、電解液原液2とした。 [Example 2]
[Preparation of non-aqueous electrolyte secondary battery]
(Preparation of non-aqueous electrolyte)
LiPF 6 was dissolved in a mixed solvent in which ethylene carbonate and diethyl carbonate were mixed at a volume ratio of 3: 7 so that the concentration thereof was 1 mol / L, to prepare an electrolyte solution stock solution 2.
ビニレンカーボネート(VC、イオン電導度低下率:1.3%)10.0mgにジエチルカーボネートを加えて溶かして5mLとし、添加液2とした。200μLの添加液2と1800μLの電解液原液2を混合し、この添加液2と電解液原液2との混合液100μLに電解液原液2を900μL加えて、添加液3とした。50μLの添加液3と1950μLの電解液原液2を混合し、非水電解液2とした。非水電解液2における前記添加剤の含有量を表2に示す。
Addition liquid 2 was prepared by adding diethyl carbonate to 10.0 mg of vinylene carbonate (VC, reduction rate of ionic conductivity: 1.3%) to make a volume of 5 mL. 200 μL of the additive solution 2 and 1800 μL of the electrolytic solution stock solution 2 were mixed, and 900 μL of the electrolytic solution stock solution 2 was added to 100 μL of the mixed solution of the additive solution 2 and the electrolytic solution stock solution 2 to give an additive solution 3. A non-aqueous electrolyte solution 2 was prepared by mixing 50 μL of the additive solution 3 and 1950 μL of the electrolyte solution stock solution 2. Table 2 shows the content of the additive in the non-aqueous electrolyte solution 2.
(非水電解液二次電池の組み立て)
非水電解液1の代わりに、非水電解液2を使用したこと以外は、実施例1と同様にして、非水電解液二次電池を作製した。作製した非水電解液二次電池を非水電解液二次電池2とした。 (Assembly of non-aqueous electrolyte secondary battery)
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the non-aqueous electrolyte solution 2 was used instead of the non-aqueous electrolyte solution 1. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 2.
非水電解液1の代わりに、非水電解液2を使用したこと以外は、実施例1と同様にして、非水電解液二次電池を作製した。作製した非水電解液二次電池を非水電解液二次電池2とした。 (Assembly of non-aqueous electrolyte secondary battery)
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the non-aqueous electrolyte solution 2 was used instead of the non-aqueous electrolyte solution 1. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 2.
その後、上述の方法にて得られた非水電解液二次電池2のハイレート放電後の充電容量の測定を行った。その結果を表2に示す。
After that, the charge capacity of the non-aqueous electrolyte secondary battery 2 obtained by the above method after high rate discharge was measured. The results are shown in Table 2.
[実施例3]
[非水電解液二次電池用セパレータと多孔質層とを備えた積層体の製造]
以下に示すこと以外は、実施例1と同様にして非水電解液二次電池用セパレータ1と多孔質層2とを備えた積層体2を得た。
・無機フィラーとして、酸素原子質量百分率が20%である六角板状酸化亜鉛(堺化学工業株式会社製、商品名:XZ-100F)を用いたこと。
・無機フィラー90重量部に対して、フッ化ビニリデン-ヘキサフルオロプロピレン共重合体を10重量部混合した後、得られる混合液における、無機フィラーおよびフッ化ビニリデン-ヘキサフルオロプロピレン共重合体からなる固形分の濃度が37重量%となるように溶媒を混合して混合液を作製したこと。
・塗工液を塗工せん断速度3.9(1/s)にて塗工することにより、多孔質層1の代わりに多孔質層2を形成したこと。 [Example 3]
[Production of Laminated Body Comprising Non-Aqueous Electrolyte Secondary Battery Separator and Porous Layer]
A laminate 2 including a separator 1 for a non-aqueous electrolyte secondary battery and a porous layer 2 was obtained in the same manner as in Example 1 except for the following.
As the inorganic filler, hexagonal plate-shaped zinc oxide having a mass percentage of oxygen atoms of 20% (manufactured by Sakai Chemical Industry Co., Ltd., trade name: XZ-100F) was used.
A solid comprising the inorganic filler and the vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid after mixing 10 parts by weight of the vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of the inorganic filler. The mixture was prepared by mixing the solvents so that the concentration of the components was 37% by weight.
The porous layer 2 was formed instead of the porous layer 1 by applying the coating liquid at a coating shear rate of 3.9 (1 / s).
[非水電解液二次電池用セパレータと多孔質層とを備えた積層体の製造]
以下に示すこと以外は、実施例1と同様にして非水電解液二次電池用セパレータ1と多孔質層2とを備えた積層体2を得た。
・無機フィラーとして、酸素原子質量百分率が20%である六角板状酸化亜鉛(堺化学工業株式会社製、商品名:XZ-100F)を用いたこと。
・無機フィラー90重量部に対して、フッ化ビニリデン-ヘキサフルオロプロピレン共重合体を10重量部混合した後、得られる混合液における、無機フィラーおよびフッ化ビニリデン-ヘキサフルオロプロピレン共重合体からなる固形分の濃度が37重量%となるように溶媒を混合して混合液を作製したこと。
・塗工液を塗工せん断速度3.9(1/s)にて塗工することにより、多孔質層1の代わりに多孔質層2を形成したこと。 [Example 3]
[Production of Laminated Body Comprising Non-Aqueous Electrolyte Secondary Battery Separator and Porous Layer]
A laminate 2 including a separator 1 for a non-aqueous electrolyte secondary battery and a porous layer 2 was obtained in the same manner as in Example 1 except for the following.
As the inorganic filler, hexagonal plate-shaped zinc oxide having a mass percentage of oxygen atoms of 20% (manufactured by Sakai Chemical Industry Co., Ltd., trade name: XZ-100F) was used.
A solid comprising the inorganic filler and the vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid after mixing 10 parts by weight of the vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of the inorganic filler. The mixture was prepared by mixing the solvents so that the concentration of the components was 37% by weight.
The porous layer 2 was formed instead of the porous layer 1 by applying the coating liquid at a coating shear rate of 3.9 (1 / s).
得られた積層体2を用いて、多孔質層表面の無機フィラーの投影像のアスペクト比およびピーク強度比の最大値を測定した。その結果を表1に示す。
Using the obtained laminate 2, the maximum values of the aspect ratio and the peak intensity ratio of the projected image of the inorganic filler on the surface of the porous layer were measured. The results are shown in Table 1.
[非水電解液二次電池の作製]
(非水電解液の作製)
エチレンカーボネート、エチルメチルカーボネート、ジエチルカーボネートを4:4:2の体積比で混合してなる混合溶媒に、LiPF6をその濃度が1mol/Lとなるように溶解して、電解液原液3とした。 [Preparation of non-aqueous electrolyte secondary battery]
(Preparation of non-aqueous electrolyte)
LiPF 6 was dissolved in a mixed solvent prepared by mixing ethylene carbonate, ethylmethyl carbonate, and diethyl carbonate at a volume ratio of 4: 4: 2 so that the concentration thereof was 1 mol / L to prepare an electrolyte solution stock solution 3. ..
(非水電解液の作製)
エチレンカーボネート、エチルメチルカーボネート、ジエチルカーボネートを4:4:2の体積比で混合してなる混合溶媒に、LiPF6をその濃度が1mol/Lとなるように溶解して、電解液原液3とした。 [Preparation of non-aqueous electrolyte secondary battery]
(Preparation of non-aqueous electrolyte)
LiPF 6 was dissolved in a mixed solvent prepared by mixing ethylene carbonate, ethylmethyl carbonate, and diethyl carbonate at a volume ratio of 4: 4: 2 so that the concentration thereof was 1 mol / L to prepare an electrolyte solution stock solution 3. ..
ペンタエリトリトールテトラキス[3-(3,5-ジ-tert-ブチル-4-ヒドロキシフェニル)プロピオナート](Irg.1010、イオン電導度低下率:4.0%)11.2mgにジエチルカーボネートを加え、溶解させて5mLとし、添加液4とした。90μLの添加液4と1910μLの電解液原液3とを混合し、非水電解液3とした。非水電解液3における添加剤の含有量を表2に示す。
Diethyl carbonate was added to 11.2 mg of pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (Irg.1010, ionic conductivity reduction rate: 4.0%), and dissolved. It was made to be 5 mL, and it was set as the addition liquid 4. 90 μL of the additive solution 4 and 1910 μL of the electrolytic solution stock solution 3 were mixed to prepare a non-aqueous electrolytic solution 3. Table 2 shows the content of the additive in the non-aqueous electrolyte solution 3.
(非水電解液二次電池の組み立て)
積層体1の代わりに、積層体2を使用して、非水電解液1の代わりに、非水電解液3を使用したこと以外は、実施例1と同様にして、非水電解液二次電池を作製した。作製した非水電解液二次電池を非水電解液二次電池3とした。 (Assembly of non-aqueous electrolyte secondary battery)
A non-aqueous electrolyte secondary was prepared in the same manner as in Example 1 except that the laminate 2 was used instead of the laminate 1 and the non-aqueous electrolyte 3 was used instead of the non-aqueous electrolyte 1. A battery was produced. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 3.
積層体1の代わりに、積層体2を使用して、非水電解液1の代わりに、非水電解液3を使用したこと以外は、実施例1と同様にして、非水電解液二次電池を作製した。作製した非水電解液二次電池を非水電解液二次電池3とした。 (Assembly of non-aqueous electrolyte secondary battery)
A non-aqueous electrolyte secondary was prepared in the same manner as in Example 1 except that the laminate 2 was used instead of the laminate 1 and the non-aqueous electrolyte 3 was used instead of the non-aqueous electrolyte 1. A battery was produced. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 3.
その後、上述の方法にて得られた非水電解液二次電池3のハイレート放電後の充電容量の測定を行った。その結果を表2に示す。
After that, the charge capacity of the non-aqueous electrolyte secondary battery 3 obtained by the above method after high rate discharge was measured. The results are shown in Table 2.
[実施例4]
[非水電解液二次電池用セパレータと多孔質層とからなる積層体の製造]
以下に示すこと以外は、実施例1と同様にして非水電解液二次電池用セパレータ1と多孔質層3とを備えた積層体3を得た。
・球状アルミナ(住友化学株式会社製、商品名AA03)50重量部と、マイカ(株式会社和光純薬製、商品名:非膨潤性合成雲母)50重量部とを、乳鉢で混合して得た酸素原子質量百分率45%の混合物を無機フィラーとして用いたこと。
・無機フィラー90重量部に対して、フッ化ビニリデン-ヘキサフルオロプロピレン共重合体を10重量部混合した後、得られる混合液における、無機フィラーおよびフッ化ビニリデン-ヘキサフルオロプロピレン共重合体からなる固形分の濃度が30重量%となるように溶媒を混合して混合液を作製したこと。
・塗工液を塗工せん断速度7.9(1/s)にて塗工することにより、多孔質層1の代わりに多孔質層3を形成したこと。 [Example 4]
[Production of Laminated Body Comprising Nonaqueous Electrolyte Secondary Battery Separator and Porous Layer]
A laminate 3 including a separator 1 for a non-aqueous electrolyte secondary battery and a porous layer 3 was obtained in the same manner as in Example 1 except for the following.
Obtained by mixing 50 parts by weight of spherical alumina (Sumitomo Chemical Co., Ltd., trade name AA03) and 50 parts by weight of mica (Wako Pure Chemical Industries, Ltd., trade name: non-swelling synthetic mica) in a mortar. A mixture having an oxygen atom mass percentage of 45% was used as an inorganic filler.
A solid comprising the inorganic filler and the vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid after mixing 10 parts by weight of the vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of the inorganic filler. The mixture was prepared by mixing the solvents so that the concentration of the components was 30% by weight.
The porous layer 3 was formed instead of the porous layer 1 by applying the coating liquid at a coating shear rate of 7.9 (1 / s).
[非水電解液二次電池用セパレータと多孔質層とからなる積層体の製造]
以下に示すこと以外は、実施例1と同様にして非水電解液二次電池用セパレータ1と多孔質層3とを備えた積層体3を得た。
・球状アルミナ(住友化学株式会社製、商品名AA03)50重量部と、マイカ(株式会社和光純薬製、商品名:非膨潤性合成雲母)50重量部とを、乳鉢で混合して得た酸素原子質量百分率45%の混合物を無機フィラーとして用いたこと。
・無機フィラー90重量部に対して、フッ化ビニリデン-ヘキサフルオロプロピレン共重合体を10重量部混合した後、得られる混合液における、無機フィラーおよびフッ化ビニリデン-ヘキサフルオロプロピレン共重合体からなる固形分の濃度が30重量%となるように溶媒を混合して混合液を作製したこと。
・塗工液を塗工せん断速度7.9(1/s)にて塗工することにより、多孔質層1の代わりに多孔質層3を形成したこと。 [Example 4]
[Production of Laminated Body Comprising Nonaqueous Electrolyte Secondary Battery Separator and Porous Layer]
A laminate 3 including a separator 1 for a non-aqueous electrolyte secondary battery and a porous layer 3 was obtained in the same manner as in Example 1 except for the following.
Obtained by mixing 50 parts by weight of spherical alumina (Sumitomo Chemical Co., Ltd., trade name AA03) and 50 parts by weight of mica (Wako Pure Chemical Industries, Ltd., trade name: non-swelling synthetic mica) in a mortar. A mixture having an oxygen atom mass percentage of 45% was used as an inorganic filler.
A solid comprising the inorganic filler and the vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid after mixing 10 parts by weight of the vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of the inorganic filler. The mixture was prepared by mixing the solvents so that the concentration of the components was 30% by weight.
The porous layer 3 was formed instead of the porous layer 1 by applying the coating liquid at a coating shear rate of 7.9 (1 / s).
得られた積層体3を用いて、多孔質層表面の無機フィラーの投影像のアスペクト比およびピーク強度比の最大値を測定した。その結果を表1に示す。
Using the obtained laminate 3, the maximum values of the aspect ratio and the peak intensity ratio of the projected image of the inorganic filler on the surface of the porous layer were measured. The results are shown in Table 1.
[非水電解液二次電池の作製]
(非水電解液の作製)
90μLの添加液4と1910μLの電解液原液1とを混合し、非水電解液4とした。非水電解液4における前記添加剤の含有量を表2に示す。 [Preparation of non-aqueous electrolyte secondary battery]
(Preparation of non-aqueous electrolyte)
90 μL of the additive solution 4 and 1910 μL of the electrolytic solution stock solution 1 were mixed to prepare a non-aqueous electrolytic solution 4. Table 2 shows the content of the additive in the non-aqueous electrolyte solution 4.
(非水電解液の作製)
90μLの添加液4と1910μLの電解液原液1とを混合し、非水電解液4とした。非水電解液4における前記添加剤の含有量を表2に示す。 [Preparation of non-aqueous electrolyte secondary battery]
(Preparation of non-aqueous electrolyte)
90 μL of the additive solution 4 and 1910 μL of the electrolytic solution stock solution 1 were mixed to prepare a non-aqueous electrolytic solution 4. Table 2 shows the content of the additive in the non-aqueous electrolyte solution 4.
(非水電解液二次電池の組み立て)
積層体1の代わりに積層体3を使用したこと、および非水電解液1の代わりに非水電解液4を使用したこと以外は、実施例1と同様にして、非水電解液二次電池を作製した。作製した非水電解液二次電池を非水電解液二次電池4とした。 (Assembly of non-aqueous electrolyte secondary battery)
A non-aqueous electrolyte secondary battery was obtained in the same manner as in Example 1 except that the laminate 3 was used instead of the laminate 1 and the non-aqueous electrolyte 4 was used instead of the non-aqueous electrolyte 1. Was produced. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 4.
積層体1の代わりに積層体3を使用したこと、および非水電解液1の代わりに非水電解液4を使用したこと以外は、実施例1と同様にして、非水電解液二次電池を作製した。作製した非水電解液二次電池を非水電解液二次電池4とした。 (Assembly of non-aqueous electrolyte secondary battery)
A non-aqueous electrolyte secondary battery was obtained in the same manner as in Example 1 except that the laminate 3 was used instead of the laminate 1 and the non-aqueous electrolyte 4 was used instead of the non-aqueous electrolyte 1. Was produced. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 4.
その後、上述の方法にて得られた非水電解液二次電池4のハイレート放電後の充電容量の測定を行った。その結果を表2に示す。
After that, the charge capacity of the non-aqueous electrolyte secondary battery 4 obtained by the above method after high rate discharge was measured. The results are shown in Table 2.
[実施例5]
[非水電解液二次電池用セパレータと多孔質層とを備えた積層体の製造]
以下に示すこと以外は、実施例1と同様にして非水電解液二次電池用セパレータ1と多孔質層4とを備えた積層体4を得た。
・無機フィラーとして、酸素原子質量百分率41%であるワラストナイト(林化成株式会社製、商品名:ワラストナイト VM-8N)を用いたこと。
・無機フィラー90重量部に対して、フッ化ビニリデン-ヘキサフルオロプロピレン共重合体を10重量部混合した後、得られる混合液における、無機フィラーおよびフッ化ビニリデン-ヘキサフルオロプロピレン共重合体からなる固形分の濃度が40重量%となるように溶媒を混合して混合液を作製したこと。
・塗工液を塗工せん断速度7.9(1/s)にて塗工することにより、多孔質層1の代わりに多孔質層4を形成したこと。 [Example 5]
[Production of Laminated Body Comprising Non-Aqueous Electrolyte Secondary Battery Separator and Porous Layer]
A laminate 4 including the separator 1 for non-aqueous electrolyte secondary battery and the porous layer 4 was obtained in the same manner as in Example 1 except for the following.
As the inorganic filler, Wollastonite (Hayashi Kasei Co., Ltd., trade name: Wollastonite VM-8N) having an oxygen atomic mass percentage of 41% was used.
A solid comprising the inorganic filler and the vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid after mixing 10 parts by weight of the vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of the inorganic filler. The mixture was prepared by mixing the solvents so that the concentration of the components was 40% by weight.
The porous layer 4 was formed instead of the porous layer 1 by applying the coating liquid at a coating shear rate of 7.9 (1 / s).
[非水電解液二次電池用セパレータと多孔質層とを備えた積層体の製造]
以下に示すこと以外は、実施例1と同様にして非水電解液二次電池用セパレータ1と多孔質層4とを備えた積層体4を得た。
・無機フィラーとして、酸素原子質量百分率41%であるワラストナイト(林化成株式会社製、商品名:ワラストナイト VM-8N)を用いたこと。
・無機フィラー90重量部に対して、フッ化ビニリデン-ヘキサフルオロプロピレン共重合体を10重量部混合した後、得られる混合液における、無機フィラーおよびフッ化ビニリデン-ヘキサフルオロプロピレン共重合体からなる固形分の濃度が40重量%となるように溶媒を混合して混合液を作製したこと。
・塗工液を塗工せん断速度7.9(1/s)にて塗工することにより、多孔質層1の代わりに多孔質層4を形成したこと。 [Example 5]
[Production of Laminated Body Comprising Non-Aqueous Electrolyte Secondary Battery Separator and Porous Layer]
A laminate 4 including the separator 1 for non-aqueous electrolyte secondary battery and the porous layer 4 was obtained in the same manner as in Example 1 except for the following.
As the inorganic filler, Wollastonite (Hayashi Kasei Co., Ltd., trade name: Wollastonite VM-8N) having an oxygen atomic mass percentage of 41% was used.
A solid comprising the inorganic filler and the vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid after mixing 10 parts by weight of the vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of the inorganic filler. The mixture was prepared by mixing the solvents so that the concentration of the components was 40% by weight.
The porous layer 4 was formed instead of the porous layer 1 by applying the coating liquid at a coating shear rate of 7.9 (1 / s).
得られた積層体4を用いて、多孔質層表面の無機フィラーの投影像のアスペクト比およびピーク強度比の最大値を測定した。その結果を表1に示す。
Using the obtained laminate 4, the maximum values of the aspect ratio and peak intensity ratio of the projected image of the inorganic filler on the surface of the porous layer were measured. The results are shown in Table 1.
[非水電解液二次電池の作製]
(非水電解液の作製)
エチレンカーボネート、エチルメチルカーボネート、ジエチルカーボネートを2:5:3の体積比で混合してなる混合溶媒に、LiPF6をその濃度が1mol/Lとなるように溶解して、電解液原液4とした。90μLの添加液4と1910μLの電解液原液4を混合し、非水電解液5とした。非水電解液5における前記添加剤の含有量を表2に示す。 [Preparation of non-aqueous electrolyte secondary battery]
(Preparation of non-aqueous electrolyte)
LiPF 6 was dissolved in a mixed solvent prepared by mixing ethylene carbonate, ethylmethyl carbonate, and diethyl carbonate in a volume ratio of 2: 5: 3 so that the concentration of LiPF 6 was 1 mol / L to prepare an electrolytic solution stock solution 4. .. 90 μL of the additive solution 4 and 1910 μL of the electrolytic solution stock solution 4 were mixed to form a non-aqueous electrolytic solution 5. Table 2 shows the content of the additive in the non-aqueous electrolyte solution 5.
(非水電解液の作製)
エチレンカーボネート、エチルメチルカーボネート、ジエチルカーボネートを2:5:3の体積比で混合してなる混合溶媒に、LiPF6をその濃度が1mol/Lとなるように溶解して、電解液原液4とした。90μLの添加液4と1910μLの電解液原液4を混合し、非水電解液5とした。非水電解液5における前記添加剤の含有量を表2に示す。 [Preparation of non-aqueous electrolyte secondary battery]
(Preparation of non-aqueous electrolyte)
LiPF 6 was dissolved in a mixed solvent prepared by mixing ethylene carbonate, ethylmethyl carbonate, and diethyl carbonate in a volume ratio of 2: 5: 3 so that the concentration of LiPF 6 was 1 mol / L to prepare an electrolytic solution stock solution 4. .. 90 μL of the additive solution 4 and 1910 μL of the electrolytic solution stock solution 4 were mixed to form a non-aqueous electrolytic solution 5. Table 2 shows the content of the additive in the non-aqueous electrolyte solution 5.
(非水電解液二次電池の組み立て)
積層体1の代わりに積層体4を使用したこと、および非水電解液1の代わりに非水電解液5を使用したこと以外は、実施例1と同様にして、非水電解液二次電池を作製した。作製した非水電解液二次電池を非水電解液二次電池5とした。 (Assembly of non-aqueous electrolyte secondary battery)
Non-aqueous electrolyte secondary battery in the same manner as in Example 1 except that the laminate 4 was used instead of the laminate 1 and the non-aqueous electrolyte 5 was used instead of the non-aqueous electrolyte 1. Was produced. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 5.
積層体1の代わりに積層体4を使用したこと、および非水電解液1の代わりに非水電解液5を使用したこと以外は、実施例1と同様にして、非水電解液二次電池を作製した。作製した非水電解液二次電池を非水電解液二次電池5とした。 (Assembly of non-aqueous electrolyte secondary battery)
Non-aqueous electrolyte secondary battery in the same manner as in Example 1 except that the laminate 4 was used instead of the laminate 1 and the non-aqueous electrolyte 5 was used instead of the non-aqueous electrolyte 1. Was produced. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 5.
その後、上述の方法にて得られた非水電解液二次電池5のハイレート放電後の充電容量の測定を行った。その結果を表2に示す。
After that, the charge capacity of the non-aqueous electrolyte secondary battery 5 obtained by the above method after high rate discharge was measured. The results are shown in Table 2.
[比較例1]
[非水電解液二次電池の作製]
(非水電解液の作製)
トリス-(4-t-ブチル-2,6-ジ-メチル-3-ヒドロキシベンジル)イソシアヌレイト(Cyanox1790、イオン電導度低下率:6.1%)9.7mgにジエチルカーボネートを加えて溶かして5mLとし、添加液5とした。90μLの添加液5と1910μLの電解液原液1を混合し、非水電解液6とした。非水電解液6における前記添加剤の含有量を表2に示す。 [Comparative Example 1]
[Preparation of non-aqueous electrolyte secondary battery]
(Preparation of non-aqueous electrolyte)
Diethyl carbonate was added to and dissolved in 9.7 mg of tris- (4-t-butyl-2,6-di-methyl-3-hydroxybenzyl) isocyanurate (Cyanox 1790, ionic conductivity reduction rate: 6.1%). The amount was 5 mL, and it was the addition liquid 5. 90 μL of the additive solution 5 and 1910 μL of the electrolytic solution stock solution 1 were mixed to prepare a non-aqueous electrolytic solution 6. Table 2 shows the content of the additive in the non-aqueous electrolyte solution 6.
[非水電解液二次電池の作製]
(非水電解液の作製)
トリス-(4-t-ブチル-2,6-ジ-メチル-3-ヒドロキシベンジル)イソシアヌレイト(Cyanox1790、イオン電導度低下率:6.1%)9.7mgにジエチルカーボネートを加えて溶かして5mLとし、添加液5とした。90μLの添加液5と1910μLの電解液原液1を混合し、非水電解液6とした。非水電解液6における前記添加剤の含有量を表2に示す。 [Comparative Example 1]
[Preparation of non-aqueous electrolyte secondary battery]
(Preparation of non-aqueous electrolyte)
Diethyl carbonate was added to and dissolved in 9.7 mg of tris- (4-t-butyl-2,6-di-methyl-3-hydroxybenzyl) isocyanurate (Cyanox 1790, ionic conductivity reduction rate: 6.1%). The amount was 5 mL, and it was the addition liquid 5. 90 μL of the additive solution 5 and 1910 μL of the electrolytic solution stock solution 1 were mixed to prepare a non-aqueous electrolytic solution 6. Table 2 shows the content of the additive in the non-aqueous electrolyte solution 6.
(非水電解液二次電池の組み立て)
非水電解液1の代わりに非水電解液6を使用したこと以外は、実施例1と同様にして、非水電解液二次電池を作製した。作製した非水電解液二次電池を非水電解液二次電池6とした。 (Assembly of non-aqueous electrolyte secondary battery)
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the non-aqueous electrolyte solution 6 was used instead of the non-aqueous electrolyte solution 1. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 6.
非水電解液1の代わりに非水電解液6を使用したこと以外は、実施例1と同様にして、非水電解液二次電池を作製した。作製した非水電解液二次電池を非水電解液二次電池6とした。 (Assembly of non-aqueous electrolyte secondary battery)
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the non-aqueous electrolyte solution 6 was used instead of the non-aqueous electrolyte solution 1. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 6.
その後、上述の方法にて得られた非水電解液二次電池6のハイレート放電後の充電容量の測定を行った。その結果を表2に示す。
After that, the charge capacity of the non-aqueous electrolyte secondary battery 6 obtained by the above method after high rate discharge was measured. The results are shown in Table 2.
[比較例2]
[非水電解液二次電池用セパレータと多孔質層とを備えた積層体の製造]
以下に示すこと以外は、実施例1と同様にして非水電解液二次電池用セパレータ1と多孔質層5とを備えた積層体5を得た。
・無機フィラーとして、酸素原子質量百分率71%であるホウ砂(和光純薬製)を用いたこと。
・無機フィラー90重量部に対して、フッ化ビニリデン-ヘキサフルオロプロピレン共重合体を10重量部混合した後、得られる混合液における無機フィラーおよびフッ化ビニリデン-ヘキサフルオロプロピレン共重合体からなる固形分の濃度が40重量%となるように溶媒を混合して混合液を作製したこと。
・塗工液を塗工せん断速度7.9(1/s)にて塗工することにより、多孔質層1の代わりに多孔質層5を形成したこと。 [Comparative Example 2]
[Production of Laminated Body Comprising Non-Aqueous Electrolyte Secondary Battery Separator and Porous Layer]
A laminate 5 including the separator 1 for non-aqueous electrolyte secondary battery and the porous layer 5 was obtained in the same manner as in Example 1 except for the following.
-As the inorganic filler, borax (manufactured by Wako Pure Chemical Industries, Ltd.) having an oxygen atomic mass percentage of 71% was used.
After mixing 10 parts by weight of vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of inorganic filler, the solid content of the inorganic filler and vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid. The solvent was mixed so as to have a concentration of 40% by weight to prepare a mixed solution.
The porous layer 5 was formed instead of the porous layer 1 by applying the coating liquid at a coating shear rate of 7.9 (1 / s).
[非水電解液二次電池用セパレータと多孔質層とを備えた積層体の製造]
以下に示すこと以外は、実施例1と同様にして非水電解液二次電池用セパレータ1と多孔質層5とを備えた積層体5を得た。
・無機フィラーとして、酸素原子質量百分率71%であるホウ砂(和光純薬製)を用いたこと。
・無機フィラー90重量部に対して、フッ化ビニリデン-ヘキサフルオロプロピレン共重合体を10重量部混合した後、得られる混合液における無機フィラーおよびフッ化ビニリデン-ヘキサフルオロプロピレン共重合体からなる固形分の濃度が40重量%となるように溶媒を混合して混合液を作製したこと。
・塗工液を塗工せん断速度7.9(1/s)にて塗工することにより、多孔質層1の代わりに多孔質層5を形成したこと。 [Comparative Example 2]
[Production of Laminated Body Comprising Non-Aqueous Electrolyte Secondary Battery Separator and Porous Layer]
A laminate 5 including the separator 1 for non-aqueous electrolyte secondary battery and the porous layer 5 was obtained in the same manner as in Example 1 except for the following.
-As the inorganic filler, borax (manufactured by Wako Pure Chemical Industries, Ltd.) having an oxygen atomic mass percentage of 71% was used.
After mixing 10 parts by weight of vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of inorganic filler, the solid content of the inorganic filler and vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid. The solvent was mixed so as to have a concentration of 40% by weight to prepare a mixed solution.
The porous layer 5 was formed instead of the porous layer 1 by applying the coating liquid at a coating shear rate of 7.9 (1 / s).
得られた積層体5を用いて、多孔質層表面の無機フィラーの投影像のアスペクト比およびピーク強度比の最大値を測定した。その結果を表1に示す。
Using the obtained laminate 5, the maximum values of the aspect ratio and peak intensity ratio of the projected image of the inorganic filler on the surface of the porous layer were measured. The results are shown in Table 1.
[非水電解液二次電池の作製]
(非水電解液二次電池の組み立て)
積層体1の代わりに積層体5を使用したこと、および非水電解液1の代わりに非水電解液4を使用したこと以外は、実施例1と同様にして、非水電解液二次電池を作製した。作製した非水電解液二次電池を非水電解液二次電池7とした。 [Preparation of non-aqueous electrolyte secondary battery]
(Assembly of non-aqueous electrolyte secondary battery)
Non-aqueous electrolyte secondary battery in the same manner as in Example 1 except that the laminate 5 was used in place of the laminate 1 and the non-aqueous electrolyte 4 was used in place of the non-aqueous electrolyte 1. Was produced. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 7.
(非水電解液二次電池の組み立て)
積層体1の代わりに積層体5を使用したこと、および非水電解液1の代わりに非水電解液4を使用したこと以外は、実施例1と同様にして、非水電解液二次電池を作製した。作製した非水電解液二次電池を非水電解液二次電池7とした。 [Preparation of non-aqueous electrolyte secondary battery]
(Assembly of non-aqueous electrolyte secondary battery)
Non-aqueous electrolyte secondary battery in the same manner as in Example 1 except that the laminate 5 was used in place of the laminate 1 and the non-aqueous electrolyte 4 was used in place of the non-aqueous electrolyte 1. Was produced. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 7.
その後、上述の方法にて得られた非水電解液二次電池7のハイレート放電後の充電容量の測定を行った。その結果を表2に示す。
After that, the charge capacity of the non-aqueous electrolyte secondary battery 7 obtained by the above method after high rate discharge was measured. The results are shown in Table 2.
[比較例3]
[非水電解液二次電池用セパレータと多孔質層とを備えた積層体の製造]
以下に示すこと以外は、実施例1と同様にして非水電解液二次電池用セパレータ1と多孔質層6とを備えた積層体6を得た。
・無機フィラーとして、酸素原子質量百分率が20%である六角板状酸化亜鉛(堺化学工業株式会社製、商品名:XZ-100F)を用いたこと。
・無機フィラー90重量部に対して、フッ化ビニリデン-ヘキサフルオロプロピレン共重合体を10重量部混合した後、得られる混合液における、無機フィラーおよびフッ化ビニリデン-ヘキサフルオロプロピレン共重合体からなる固形分の濃度が37重量%となるように溶媒を混合して混合液を作製したこと。
・塗工液を塗工せん断速度0.4(1/s)で塗工することにより、多孔質層1の代わりに多孔質層6を形成したこと。 [Comparative Example 3]
[Production of Laminated Body Comprising Non-Aqueous Electrolyte Secondary Battery Separator and Porous Layer]
A laminate 6 including the separator 1 for non-aqueous electrolyte secondary battery and the porous layer 6 was obtained in the same manner as in Example 1 except for the following.
As the inorganic filler, hexagonal plate-shaped zinc oxide having a mass percentage of oxygen atoms of 20% (manufactured by Sakai Chemical Industry Co., Ltd., trade name: XZ-100F) was used.
A solid comprising the inorganic filler and the vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid after mixing 10 parts by weight of the vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of the inorganic filler. The mixture was prepared by mixing the solvents so that the concentration of the components was 37% by weight.
The porous layer 6 was formed instead of the porous layer 1 by applying the coating liquid at a coating shear rate of 0.4 (1 / s).
[非水電解液二次電池用セパレータと多孔質層とを備えた積層体の製造]
以下に示すこと以外は、実施例1と同様にして非水電解液二次電池用セパレータ1と多孔質層6とを備えた積層体6を得た。
・無機フィラーとして、酸素原子質量百分率が20%である六角板状酸化亜鉛(堺化学工業株式会社製、商品名:XZ-100F)を用いたこと。
・無機フィラー90重量部に対して、フッ化ビニリデン-ヘキサフルオロプロピレン共重合体を10重量部混合した後、得られる混合液における、無機フィラーおよびフッ化ビニリデン-ヘキサフルオロプロピレン共重合体からなる固形分の濃度が37重量%となるように溶媒を混合して混合液を作製したこと。
・塗工液を塗工せん断速度0.4(1/s)で塗工することにより、多孔質層1の代わりに多孔質層6を形成したこと。 [Comparative Example 3]
[Production of Laminated Body Comprising Non-Aqueous Electrolyte Secondary Battery Separator and Porous Layer]
A laminate 6 including the separator 1 for non-aqueous electrolyte secondary battery and the porous layer 6 was obtained in the same manner as in Example 1 except for the following.
As the inorganic filler, hexagonal plate-shaped zinc oxide having a mass percentage of oxygen atoms of 20% (manufactured by Sakai Chemical Industry Co., Ltd., trade name: XZ-100F) was used.
A solid comprising the inorganic filler and the vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid after mixing 10 parts by weight of the vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of the inorganic filler. The mixture was prepared by mixing the solvents so that the concentration of the components was 37% by weight.
The porous layer 6 was formed instead of the porous layer 1 by applying the coating liquid at a coating shear rate of 0.4 (1 / s).
得られた積層体6を用いて、多孔質層表面の無機フィラーの投影像のアスペクト比およびピーク強度比の最大値を測定した。その結果を表1に示す。
Using the obtained layered product 6, the maximum values of the aspect ratio and the peak intensity ratio of the projected image of the inorganic filler on the surface of the porous layer were measured. The results are shown in Table 1.
[非水電解液二次電池の作製]
(非水電解液二次電池の組み立て)
積層体1の代わりに積層体6を使用したこと、および非水電解液1の代わりに非水電解液4を使用したこと以外は、実施例1と同様にして、非水電解液二次電池を作製した。作製した非水電解液二次電池を非水電解液二次電池8とした。 [Preparation of non-aqueous electrolyte secondary battery]
(Assembly of non-aqueous electrolyte secondary battery)
Nonaqueous electrolyte secondary battery in the same manner as in Example 1 except that the laminate 6 was used in place of the laminate 1 and the nonaqueous electrolyte 4 was used in place of the nonaqueous electrolyte 1. Was produced. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 8.
(非水電解液二次電池の組み立て)
積層体1の代わりに積層体6を使用したこと、および非水電解液1の代わりに非水電解液4を使用したこと以外は、実施例1と同様にして、非水電解液二次電池を作製した。作製した非水電解液二次電池を非水電解液二次電池8とした。 [Preparation of non-aqueous electrolyte secondary battery]
(Assembly of non-aqueous electrolyte secondary battery)
Nonaqueous electrolyte secondary battery in the same manner as in Example 1 except that the laminate 6 was used in place of the laminate 1 and the nonaqueous electrolyte 4 was used in place of the nonaqueous electrolyte 1. Was produced. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 8.
その後、上述の方法にて得られた非水電解液二次電池8のハイレート放電後の充電容量の測定を行った。その結果を表2に示す。
After that, the charge capacity of the non-aqueous electrolyte secondary battery 8 obtained by the above method after high rate discharge was measured. The results are shown in Table 2.
[比較例4]
[非水電解液二次電池用セパレータと多孔質層とを備えた積層体の製造]
以下に示すこと以外は、実施例1と同様にして非水電解液二次電池用セパレータ1と多孔質層7とを備えた積層体7を得た。
・無機フィラーとして、酸素原子質量百分率48%であるアタパルジャイト(林化成株式会社製、商品名:ATTAGEL#50)を用いたこと。
・無機フィラー90重量部に対して、フッ化ビニリデン-ヘキサフルオロプロピレン共重合体を10重量部混合した後、得られる混合液における、無機フィラーおよびフッ化ビニリデン-ヘキサフルオロプロピレン共重合体からなる固形分の濃度が17重量%となるように溶媒を混合して混合液を作製したこと。
・非水電解液二次電池用セパレータの片面にドクターブレード法により塗工せん断速度を1.3(1/s)で塗工液を塗工することにより、多孔質層1の代わりに多孔質層7を形成したこと。 [Comparative Example 4]
[Production of Laminated Body Comprising Non-Aqueous Electrolyte Secondary Battery Separator and Porous Layer]
A laminate 7 including the non-aqueous electrolyte secondary battery separator 1 and the porous layer 7 was obtained in the same manner as in Example 1 except for the following.
As the inorganic filler, attapulgite (Hayashi Kasei Co., Ltd., trade name: ATTAGEL # 50) having an oxygen atomic mass percentage of 48% was used.
A solid comprising the inorganic filler and the vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid after mixing 10 parts by weight of the vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of the inorganic filler. The mixture was prepared by mixing the solvents so that the concentration of the components became 17% by weight.
・ A non-aqueous electrolyte secondary battery separator is coated with a coating solution at a coating shear rate of 1.3 (1 / s) on one side by a doctor blade method, so that it is porous instead of the porous layer 1. Formed layer 7.
[非水電解液二次電池用セパレータと多孔質層とを備えた積層体の製造]
以下に示すこと以外は、実施例1と同様にして非水電解液二次電池用セパレータ1と多孔質層7とを備えた積層体7を得た。
・無機フィラーとして、酸素原子質量百分率48%であるアタパルジャイト(林化成株式会社製、商品名:ATTAGEL#50)を用いたこと。
・無機フィラー90重量部に対して、フッ化ビニリデン-ヘキサフルオロプロピレン共重合体を10重量部混合した後、得られる混合液における、無機フィラーおよびフッ化ビニリデン-ヘキサフルオロプロピレン共重合体からなる固形分の濃度が17重量%となるように溶媒を混合して混合液を作製したこと。
・非水電解液二次電池用セパレータの片面にドクターブレード法により塗工せん断速度を1.3(1/s)で塗工液を塗工することにより、多孔質層1の代わりに多孔質層7を形成したこと。 [Comparative Example 4]
[Production of Laminated Body Comprising Non-Aqueous Electrolyte Secondary Battery Separator and Porous Layer]
A laminate 7 including the non-aqueous electrolyte secondary battery separator 1 and the porous layer 7 was obtained in the same manner as in Example 1 except for the following.
As the inorganic filler, attapulgite (Hayashi Kasei Co., Ltd., trade name: ATTAGEL # 50) having an oxygen atomic mass percentage of 48% was used.
A solid comprising the inorganic filler and the vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid after mixing 10 parts by weight of the vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of the inorganic filler. The mixture was prepared by mixing the solvents so that the concentration of the components became 17% by weight.
・ A non-aqueous electrolyte secondary battery separator is coated with a coating solution at a coating shear rate of 1.3 (1 / s) on one side by a doctor blade method, so that it is porous instead of the porous layer 1. Formed layer 7.
得られた積層体7を用いて、多孔質層表面の無機フィラーの投影像のアスペクト比およびピーク強度比の最大値を測定した。その結果を表1に示す。
Using the obtained laminate 7, the maximum values of the aspect ratio and the peak intensity ratio of the projected image of the inorganic filler on the surface of the porous layer were measured. The results are shown in Table 1.
[非水電解液二次電池の作製]
(非水電解液二次電池の組み立て)
積層体1の代わりに積層体7を使用したこと、および非水電解液1の代わりに非水電解液4を使用したこと以外は、実施例1と同様にして、非水電解液二次電池を作製した。作製した非水電解液二次電池を非水電解液二次電池9とした。 [Preparation of non-aqueous electrolyte secondary battery]
(Assembly of non-aqueous electrolyte secondary battery)
Non-aqueous electrolyte secondary battery in the same manner as in Example 1 except that the laminate 7 was used in place of the laminate 1 and the non-aqueous electrolyte 4 was used in place of the non-aqueous electrolyte 1. Was produced. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 9.
(非水電解液二次電池の組み立て)
積層体1の代わりに積層体7を使用したこと、および非水電解液1の代わりに非水電解液4を使用したこと以外は、実施例1と同様にして、非水電解液二次電池を作製した。作製した非水電解液二次電池を非水電解液二次電池9とした。 [Preparation of non-aqueous electrolyte secondary battery]
(Assembly of non-aqueous electrolyte secondary battery)
Non-aqueous electrolyte secondary battery in the same manner as in Example 1 except that the laminate 7 was used in place of the laminate 1 and the non-aqueous electrolyte 4 was used in place of the non-aqueous electrolyte 1. Was produced. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 9.
その後、上述の方法にて得られた非水電解液二次電池9のハイレート放電後の充電容量の測定を行った。その結果を表2に示す。
After that, the charge capacity of the non-aqueous electrolyte secondary battery 9 obtained by the above method after high rate discharge was measured. The results are shown in Table 2.
[比較例5]
[非水電解液二次電池用セパレータと多孔質層とを備えた積層体の製造]
以下に示すこと以外は、実施例1と同様にして非水電解液二次電池用セパレータ1と多孔質層8とを備えた積層体8を得た。
・無機フィラーとして、酸素原子質量百分率44%であるマイカ(和光純薬製、商品名:非膨潤性雲母)を用いたこと。
・無機フィラー90重量部に対して、フッ化ビニリデン-ヘキサフルオロプロピレン共重合体を10重量部混合した後、得られる混合液における、無機フィラーおよびフッ化ビニリデン-ヘキサフルオロプロピレン共重合体からなる固形分の濃度が20重量%となるように溶媒を混合した混合液を作製したこと。
・非水電解液二次電池用セパレータの片面にドクターブレード法により塗工せん断速度0.4(1/s)で塗工液を塗工することにより、多孔質層1の代わりに多孔質層8を形成したこと。 [Comparative Example 5]
[Production of Laminated Body Comprising Non-Aqueous Electrolyte Secondary Battery Separator and Porous Layer]
A laminate 8 including the separator 1 for a non-aqueous electrolyte secondary battery and the porous layer 8 was obtained in the same manner as in Example 1 except for the following.
-Mica (manufactured by Wako Pure Chemical Industries, trade name: non-swelling mica) having an oxygen atomic mass percentage of 44% was used as the inorganic filler.
A solid comprising the inorganic filler and the vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid after mixing 10 parts by weight of the vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of the inorganic filler. A mixed solution was prepared by mixing the solvents so that the concentration of the components was 20% by weight.
A porous layer instead of the porous layer 1 is formed by applying the coating solution on one surface of the separator for a non-aqueous electrolyte secondary battery by a doctor blade method at a coating shear rate of 0.4 (1 / s). Formed 8.
[非水電解液二次電池用セパレータと多孔質層とを備えた積層体の製造]
以下に示すこと以外は、実施例1と同様にして非水電解液二次電池用セパレータ1と多孔質層8とを備えた積層体8を得た。
・無機フィラーとして、酸素原子質量百分率44%であるマイカ(和光純薬製、商品名:非膨潤性雲母)を用いたこと。
・無機フィラー90重量部に対して、フッ化ビニリデン-ヘキサフルオロプロピレン共重合体を10重量部混合した後、得られる混合液における、無機フィラーおよびフッ化ビニリデン-ヘキサフルオロプロピレン共重合体からなる固形分の濃度が20重量%となるように溶媒を混合した混合液を作製したこと。
・非水電解液二次電池用セパレータの片面にドクターブレード法により塗工せん断速度0.4(1/s)で塗工液を塗工することにより、多孔質層1の代わりに多孔質層8を形成したこと。 [Comparative Example 5]
[Production of Laminated Body Comprising Non-Aqueous Electrolyte Secondary Battery Separator and Porous Layer]
A laminate 8 including the separator 1 for a non-aqueous electrolyte secondary battery and the porous layer 8 was obtained in the same manner as in Example 1 except for the following.
-Mica (manufactured by Wako Pure Chemical Industries, trade name: non-swelling mica) having an oxygen atomic mass percentage of 44% was used as the inorganic filler.
A solid comprising the inorganic filler and the vinylidene fluoride-hexafluoropropylene copolymer in the resulting mixed liquid after mixing 10 parts by weight of the vinylidene fluoride-hexafluoropropylene copolymer with 90 parts by weight of the inorganic filler. A mixed solution was prepared by mixing the solvents so that the concentration of the components was 20% by weight.
A porous layer instead of the porous layer 1 is formed by applying the coating solution on one surface of the separator for a non-aqueous electrolyte secondary battery by a doctor blade method at a coating shear rate of 0.4 (1 / s). Formed 8.
得られた積層体8を用いて、多孔質層表面の無機フィラーの投影像のアスペクト比およびピーク強度比の最大値を測定した。その結果を表1に示す。
Using the obtained layered product 8, the maximum values of the aspect ratio and the peak intensity ratio of the projected image of the inorganic filler on the surface of the porous layer were measured. The results are shown in Table 1.
[非水電解液二次電池の作製]
(非水電解液二次電池の組み立て)
積層体1の代わりに積層体8を使用したこと、および非水電解液1の代わりに非水電解液4を使用したこと以外は、実施例1と同様にして、非水電解液二次電池を作製した。作製した非水電解液二次電池を非水電解液二次電池10とした。 [Preparation of non-aqueous electrolyte secondary battery]
(Assembly of non-aqueous electrolyte secondary battery)
Non-aqueous electrolyte secondary battery was manufactured in the same manner as in Example 1 except that the laminate 8 was used instead of the laminate 1 and the non-aqueous electrolyte 4 was used instead of the non-aqueous electrolyte 1. Was produced. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 10.
(非水電解液二次電池の組み立て)
積層体1の代わりに積層体8を使用したこと、および非水電解液1の代わりに非水電解液4を使用したこと以外は、実施例1と同様にして、非水電解液二次電池を作製した。作製した非水電解液二次電池を非水電解液二次電池10とした。 [Preparation of non-aqueous electrolyte secondary battery]
(Assembly of non-aqueous electrolyte secondary battery)
Non-aqueous electrolyte secondary battery was manufactured in the same manner as in Example 1 except that the laminate 8 was used instead of the laminate 1 and the non-aqueous electrolyte 4 was used instead of the non-aqueous electrolyte 1. Was produced. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 10.
その後、上述の方法にて得られた非水電解液二次電池10のハイレート放電後の充電容量の測定を行った。その結果を表2に示す。
After that, the charge capacity of the non-aqueous electrolyte secondary battery 10 obtained by the above method after high rate discharge was measured. The results are shown in Table 2.
[比較例6]
[非水電解液二次電池の作製]
(非水電解液二次電池の組み立て)
非水電解液1の代わりに、電解液原液1を使用したこと以外は、実施例1と同様にして、非水電解液二次電池を作製した。作製した非水電解液二次電池を非水電解液二次電池11とした。 [Comparative Example 6]
[Preparation of non-aqueous electrolyte secondary battery]
(Assembly of non-aqueous electrolyte secondary battery)
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the electrolyte solution 1 was used instead of the non-aqueous electrolyte solution 1. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 11.
[非水電解液二次電池の作製]
(非水電解液二次電池の組み立て)
非水電解液1の代わりに、電解液原液1を使用したこと以外は、実施例1と同様にして、非水電解液二次電池を作製した。作製した非水電解液二次電池を非水電解液二次電池11とした。 [Comparative Example 6]
[Preparation of non-aqueous electrolyte secondary battery]
(Assembly of non-aqueous electrolyte secondary battery)
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the electrolyte solution 1 was used instead of the non-aqueous electrolyte solution 1. The produced non-aqueous electrolyte secondary battery was used as a non-aqueous electrolyte secondary battery 11.
その後、上述の方法にて得られた非水電解液二次電池11のハイレート放電後の充電容量の測定を行った。その結果を表2に示す。
After that, the charge capacity of the non-aqueous electrolyte secondary battery 11 obtained by the above method after high rate discharge was measured. The results are shown in Table 2.
[結果]
[Result]
表1、2の記載から、(i)「表面フィラーアスペクト比」の要件、(ii)広角X線回折法により測定した、互いに直交する任意の回折面(hkl)、(abc)のピーク強度に関する要件、並びに、(iii)非水電解液に含まれる添加剤のイオン電導度低下率および含有量に関する要件を充足する本発明の一実施形態に係る非水電解液二次電池は、ハイレート放電(3C放電)後の1C充電容量に優れることが示された。
From the descriptions in Tables 1 and 2, regarding (i) the requirement of "surface filler aspect ratio", (ii) the peak intensity of arbitrary diffractive surfaces (hkl) and (abc) which are orthogonal to each other measured by the wide-angle X-ray diffraction method. A non-aqueous electrolyte secondary battery according to an embodiment of the present invention that satisfies the requirements and (iii) the requirements regarding the ionic conductivity reduction rate and the content of the additive contained in the non-aqueous electrolyte is a high-rate discharge ( It was shown that the 1C charge capacity after 3C discharge) was excellent.
本発明の一実施形態に係る非水電解液二次電池は、ハイレート放電後の充電容量に優れるため、パーソナルコンピュータ、携帯電話および携帯情報端末などに用いる電池、並びに、車載用電池として好適に利用することができる。
The non-aqueous electrolyte secondary battery according to an embodiment of the present invention is excellent in charge capacity after high-rate discharge, and thus is suitably used as a battery used in personal computers, mobile phones, personal digital assistants, and the like, and as a vehicle battery. can do.
Claims (6)
- 無機フィラーと樹脂とを含む多孔質層、非水電解液、正極および負極を備え、
前記多孔質層の表面の、無機フィラーの投影像のアスペクト比が、1.4~4.0の範囲であり、
前記多孔質層の、広角X線回折法により測定した、互いに直交する任意の回折面(hkl)、(abc)のピーク強度:I(hkl)およびI(abc)が下式(1)を満たし、
下式(2)で算出されるピーク強度比の最大値の範囲が、1.5~300の範囲であり、
I(hkl) > I(abc)・・・(1)、
I(hkl) / I(abc)・・・(2)
前記非水電解液は、下記式(A)で表されるイオン電導度低下率Lが1.0%以上、6.0%以下である添加剤を0.5ppm以上、300ppm以下含有する、非水電解液二次電池。
L=(LA-LB)/LA・・・(A)
(式(A)中、LAは、エチレンカーボネート、エチルメチルカーボネートおよびジエチルカーボネートを3:5:2の体積比で含む混合溶媒に、LiPF6をその濃度が1mol/Lとなるように溶解させた参照用電解液のイオン電導度(mS/cm)を表し、
LBは、前記参照用電解液に、添加剤を1.0重量%溶解させた電解液のイオン電導度(mS/cm)を表す。) A porous layer containing an inorganic filler and a resin, a non-aqueous electrolyte, a positive electrode and a negative electrode,
The aspect ratio of the projected image of the inorganic filler on the surface of the porous layer is in the range of 1.4 to 4.0,
Peak strengths of arbitrary diffraction planes (hkl) and (abc) orthogonal to each other, measured by a wide-angle X-ray diffraction method, of the porous layer: I (hkl) and I (abc) satisfy the following formula (1). ,
The range of the maximum value of the peak intensity ratio calculated by the following equation (2) is in the range of 1.5 to 300,
I (hkl) > I (abc) ... (1),
I (hkl) / I (abc)・ ・ ・ (2)
The non-aqueous electrolyte contains 0.5 ppm or more and 300 ppm or less of an additive having an ionic conductivity decrease rate L represented by the following formula (A) of 1.0% or more and 6.0% or less. Water electrolyte secondary battery.
L = (LA-LB) / LA ... (A)
(In the formula (A), LA was prepared by dissolving LiPF 6 in a mixed solvent containing ethylene carbonate, ethylmethyl carbonate and diethyl carbonate in a volume ratio of 3: 5: 2 such that the concentration thereof was 1 mol / L. Represents the ionic conductivity (mS / cm) of the reference electrolyte,
LB represents the ionic conductivity (mS / cm) of the electrolytic solution prepared by dissolving 1.0% by weight of the additive in the reference electrolytic solution. ) - 前記多孔質層が、ポリオレフィン多孔質フィルムの片面または両面に積層されている、請求項1に記載の非水電解液二次電池。 The non-aqueous electrolyte secondary battery according to claim 1, wherein the porous layer is laminated on one side or both sides of a polyolefin porous film.
- 前記多孔質層が、ポリオレフィン、(メタ)アクリレート系樹脂、含フッ素樹脂、ポリアミド系樹脂、ポリエステル系樹脂および水溶性ポリマーからなる群より1種以上選択される樹脂を含む、請求項1または2に記載の非水電解液二次電池。 The porous layer contains a resin selected from the group consisting of a polyolefin, a (meth) acrylate resin, a fluorine-containing resin, a polyamide resin, a polyester resin, and a water-soluble polymer. The non-aqueous electrolyte secondary battery described.
- 上記ポリアミド系樹脂がアラミド樹脂である、請求項3に記載の非水電解液二次電池。 The non-aqueous electrolyte secondary battery according to claim 3, wherein the polyamide resin is an aramid resin.
- 前記非水電解液が、リチウムを含有している電解質を含む、請求項1~4の何れか1項に記載の非水電解液二次電池。 The non-aqueous electrolyte secondary battery according to any one of claims 1 to 4, wherein the non-aqueous electrolyte contains an electrolyte containing lithium.
- 前記非水電解液が、非プロトン性極性溶媒を含む、請求項1~5の何れか1項に記載の非水電解液二次電池。 The non-aqueous electrolyte secondary battery according to any one of claims 1 to 5, wherein the non-aqueous electrolyte contains an aprotic polar solvent.
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