JP6203910B2 - Insulating porous layer for non-aqueous electrolyte secondary battery and laminated separator for non-aqueous electrolyte secondary battery - Google Patents

Description

  The present invention relates to an insulating porous layer for a non-aqueous electrolyte secondary battery and a laminated separator for a non-aqueous electrolyte secondary battery.

  Non-aqueous electrolyte secondary batteries, particularly lithium secondary batteries, are widely used as batteries for personal computers, mobile phones, portable information terminals and the like because of their high energy density.

  Non-aqueous electrolyte secondary batteries represented by these lithium secondary batteries are high in energy density, and when internal short circuit / external short circuit occurs due to damage of the battery or equipment using the battery, A large current flows and generates intense heat. Therefore, non-aqueous electrolyte secondary batteries are required to prevent heat generation beyond a certain level and ensure high safety.

  As a means for ensuring such safety, a method of providing a shutdown function for preventing further heat generation by blocking the passage of ions between the positive and negative electrodes by a separator in the event of abnormal heat generation is common. As a method for imparting a shutdown function to the separator, a method in which a porous film made of a material that melts when abnormal heat is generated is used as the separator. That is, in the battery using the separator, the porous film melts and becomes non-porous when abnormal heat is generated, and the passage of ions can be blocked and further heat generation can be suppressed.

  As a separator having such shutdown characteristics, a separator composed of a porous layer composed of a mixture of an inorganic filler and a binder polymer, and a laminate formed by laminating the porous layer on a porous substrate. A laminated separator is mentioned.

  Moreover, the separator which uses various metal salt fine particles as said inorganic filler is proposed (patent document 1). Furthermore, as the metal salt fine particles, a separator using fine particles made of magnesium oxide (Patent Document 2) and a separator using fine particles made of alumina and / or magnesium oxide (Patent Document 3) have been proposed.

JP 2005-196999 A (published July 21, 2005) Japanese Patent No. 4476254 (issued on June 9, 2010) JP 2009-146822 A (published July 2, 2009)

  However, the above-described conventional separator for non-aqueous electrolyte secondary batteries composed of a porous layer and the multilayer separator for non-aqueous electrolyte secondary batteries including the porous layer have a problem that the discharge output characteristics are still insufficient. Have

  In order to solve the above-mentioned problems, the inventors have described the inorganic porous layer containing an inorganic filler as a member of a non-aqueous electrolyte secondary battery or a laminated separator for a non-aqueous electrolyte secondary battery. By controlling the Lewis acidity of the filler, a non-aqueous electrolyte secondary battery incorporating the insulating porous layer as a separator, or a non-aqueous electrolyte layer provided with the insulating porous layer on one side or both sides of the porous film The inventors have found that the discharge output characteristics of a non-aqueous electrolyte secondary battery incorporating a laminated separator for a water electrolyte secondary battery are improved, and have arrived at the present invention.

  That is, the present invention provides an insulating porous layer for a non-aqueous electrolyte secondary battery, a laminated separator for a non-aqueous electrolyte secondary battery, a member for a non-aqueous electrolyte secondary battery, or a non-aqueous electrolyte solution 2 shown below. Next battery.

The insulating porous layer for a non-aqueous electrolyte secondary battery of the present invention includes a metal salt fine particle, and a Lewis acid peak per unit weight of the metal salt measured by a solid surface acid property evaluation method by infrared spectroscopy. The area is 0.2 or more and 3.6 or less.
(Here, the Lewis acid peak area per unit weight of the metal salt is a peak existing in the region from 1447 to 1460 cm ⁻¹ in the infrared absorption (IR) spectrum measured from the sample after adsorption and desorption of pyridine. The peak area is divided by the weight of the metal salt used in the measurement.)
In the insulating porous layer for a non-aqueous electrolyte secondary battery of the present invention, the metal salt fine particles preferably contain titanium oxide, and more preferably contain aluminum element and titanium element. . Moreover, it is preferable that the metal salt fine particles contain a metal salt in the form of a solid solution. Furthermore, the metal salt fine particles are preferably a pulverized product. In addition, the metal salt fine particles are preferably composed of a mixture of two or more metal salts.

The laminated separator for a non-aqueous electrolyte secondary battery according to the present invention is a laminated separator for a non-aqueous electrolyte secondary battery in which an insulating porous layer is laminated on one side or both sides of a porous film mainly composed of polyolefin. The insulating porous layer contains metal salt fine particles, and the Lewis acid peak area per unit weight of the metal salt measured by a solid surface acid property evaluation method by infrared spectroscopy is 0.2. The multilayer separator for a nonaqueous electrolyte secondary battery, which is 3.6 or less.
(Here, the Lewis acid peak area per unit weight of the metal salt is a peak existing in the region from 1447 to 1460 cm ⁻¹ in the infrared absorption (IR) spectrum measured from the sample after adsorption and desorption of pyridine. The peak area is divided by the weight of the metal salt used in the measurement.)
In the multilayer separator for a non-aqueous electrolyte secondary battery of the present invention, the metal salt fine particles preferably contain titanium oxide, and more preferably contain aluminum element and titanium element. Moreover, it is preferable that the metal salt fine particles contain a metal salt in the form of a solid solution. Furthermore, the metal salt fine particles are preferably a pulverized product. In addition, the metal salt fine particles are preferably composed of a mixture of two or more metal salts.

  A member for a non-aqueous electrolyte secondary battery of the present invention is a non-aqueous battery characterized in that a positive electrode, an insulating porous layer for a non-aqueous electrolyte secondary battery of the present invention, and a negative electrode are arranged in this order. It may be a member for an electrolyte secondary battery. The nonaqueous electrolyte secondary battery member of the present invention is a nonaqueous electrolysis characterized in that a positive electrode, a laminated separator for a nonaqueous electrolyte secondary battery of the present invention, and a negative electrode are arranged in this order. It may also be a member for a liquid secondary battery.

  The non-aqueous electrolyte secondary battery of the present invention includes the insulating porous layer for a non-aqueous electrolyte secondary battery of the present invention or the laminated separator for a non-aqueous electrolyte secondary battery of the present invention. It is a non-aqueous electrolyte secondary battery.

  The separator for a non-aqueous electrolyte secondary battery or the laminated separator for a non-aqueous electrolyte secondary battery according to the present invention is incorporated in the non-aqueous electrolyte secondary battery, thereby discharging the non-aqueous electrolyte secondary battery. Characteristics can be improved. Similarly, the non-aqueous electrolyte secondary battery member can improve the discharge output characteristics of the non-aqueous electrolyte secondary battery by being incorporated in the non-aqueous electrolyte secondary battery. In addition, the nonaqueous electrolyte secondary battery of the present invention is superior in discharge output characteristics than conventional nonaqueous electrolyte secondary batteries.

It is a figure showing the flow of the measuring method of the Lewis' acid peak area implemented in the Example and the comparative example.

  Hereinafter, the present invention will be described in detail. Hereinafter, the description “A to B” means “A or more and B or less”.

[Embodiment 1: Insulating porous layer for nonaqueous electrolyte secondary battery, Embodiment 2: Multilayer separator for nonaqueous electrolyte secondary battery]
The insulating porous layer for a non-aqueous electrolyte secondary battery according to Embodiment 1 of the present invention includes metal salt fine particles, and the unit weight of the metal salt measured by an acid property evaluation method for a solid surface by infrared spectroscopy The Lewis acid peak area per area is 0.2 or more and 3.6 or less.

  The laminated separator for a nonaqueous electrolyte secondary battery according to Embodiment 2 of the present invention is a nonaqueous electrolyte solution in which an insulating porous layer is laminated on one side or both sides of a porous film mainly composed of polyolefin. A multilayer separator for a secondary battery, wherein the insulating porous layer includes metal salt fine particles, and a Lewis acid peak area per unit weight of the metal salt measured by an acid property evaluation method for a solid surface by infrared spectroscopy Is 0.2 or more and 3.6 or less.

  Below, each member which comprises the insulating porous layer for nonaqueous electrolyte secondary batteries and the non-aqueous electrolyte secondary battery laminated separator of this invention is demonstrated in detail.

[Insulating porous layer]
The insulating porous layer for a nonaqueous electrolyte secondary battery of the present invention (insulating porous layer) can be a separator for a nonaqueous electrolyte secondary battery alone, for example, in the form of an electrode coat layer, or By laminating on a porous film described later, it can be used as a member of a laminated separator for a non-aqueous electrolyte secondary battery.

  In the insulating porous layer for a non-aqueous electrolyte secondary battery and the laminated separator for a non-aqueous electrolyte secondary battery of the present invention, the Lewis acid peak area per unit weight of the metal salt fine particles contained in the insulating porous layer is 0.2 or more, 3.6 or less, preferably 0.25 or more and 3.55 or less, and more preferably 0.3 or more and 3.5 or less.

The Lewis acid peak area per unit weight of the metal salt herein is in the region from 1447 to 1460 cm ⁻¹ in the infrared absorption (IR) spectrum measured from the sample after adsorption and desorption of pyridine. It is calculated by dividing the peak area of the peak by the weight of the metal salt used in the measurement.

  Specifically, the Lewis acid peak area per unit weight of the metal salt is calculated by the following method.

First, 40 mg of metal salt fine particles, which are raw materials for the filler, are weighed and formed into a disk-shaped pellet. The pellet is placed in a heat-transmitting in-situ cell at room temperature, evacuated, and then the cell. The internal temperature is raised to 500 ° C. and the temperature is maintained for 60 minutes. After cooling to 30 ° C., using a Nicolet Co. Fourier transform infrared spectrophotometer Avatar 360, resolution 4 cm ^-1, cumulated number 256, under the conditions of the measurement region wavenumber 4000cm ^-1 ~400cm ^-1, infrared A transmission spectrum is measured, and the obtained spectrum is used as a background spectrum.

  Subsequently, the temperature inside the cell is raised to 100 ° C., pyridine vapor is introduced into the cell, and pyridine is adsorbed on the pellets over 5 minutes. Thereafter, the temperature inside the cell is raised to 150 ° C., and the temperature is maintained for 60 minutes to desorb the physically adsorbed pyridine from the pellet made of the metal salt fine particles, and then the temperature inside the cell Is reduced to 30 ° C., and the infrared transmission spectrum of the sample after adsorption and desorption of pyridine is measured under the same conditions as the measurement conditions of the infrared transmission spectrum described above.

Thereafter, based on the two infrared transmission spectra measured, the peak area existing in the region from 1447 to 1460 cm ⁻¹ , which is a peak derived from Lewis acid, is calculated. That is, an infrared absorption spectrum is obtained by subtracting the background infrared transmission spectrum from the infrared transmission spectrum after pyridine is adsorbed and desorbed, and then the base is obtained from both ends of the peak existing in the region from 1447 to 1460 cm ^−1. A line is drawn and the area surrounded by the base line and the peak is defined as the peak area. The peak area per unit weight of the metal salt is calculated by dividing the peak area by the weight of the metal salt (40 mg).

  The Lewis acid peak area per unit weight of the metal salt fine particles contained in the insulating porous layer represents the Lewis acidity per unit weight of the metal salt fine particles. When the Lewis acidity per unit weight of the metal salt fine particles is high, in the non-aqueous electrolyte secondary battery including the insulating porous layer as a separator or a member of a laminated separator, the electrolysis in the non-aqueous electrolyte secondary battery The affinity between the liquid solvent and the metal salt fine particles is increased.

In a non-aqueous electrolyte secondary battery, an insulating porous layer that is a member of a non-aqueous electrolyte secondary battery laminated separator or a non-aqueous electrolyte secondary battery as a separator during operation Cation (for example, Li ^{+ in} the case of a lithium ion secondary battery) passes through and is desolvated and then taken into the positive electrode. Here, the desolvation process is one factor of the internal resistance of the nonaqueous electrolyte secondary battery. Therefore, by promoting the desolvation, the internal resistance of the nonaqueous electrolyte secondary battery can be reduced and the output characteristics of the battery can be improved.

  Here, the ease of the desolvation described above is affected by the affinity of the components constituting the insulating porous layer, particularly the metal salt fine particles contained therein, and the electrolyte solvent. Therefore, the output characteristics of the nonaqueous electrolyte secondary battery can be improved by setting the Lewis acidity per unit weight of the metal salt fine particles contained in the insulating porous layer to an appropriate range.

Specifically, in the insulating porous layer in which the Lewis acid peak area per unit weight of the metal salt fine particles contained in the insulating porous layer for a non-aqueous electrolyte secondary battery is less than 0.2, Since the Lewis acidity is too low, it cannot interact with a solvent molecule (Lewis base) solvated with the cation (for example, Li ⁺ ), and the above-mentioned desolvation rate is not improved. Therefore, output characteristics do not improve in the nonaqueous electrolyte secondary battery in which the insulating porous layer is incorporated as a separator or a separator member. On the other hand, in the insulating porous layer in which the Lewis acid peak area per unit weight of the metal salt fine particles contained in the insulating porous layer is larger than 3.6, the Lewis acidity of the filler is too high. The acidity activates the solvent molecules that are Lewis bases, and reactions that generate decomposition gas of solvent molecules and side reactions that generate by-products that cause deterioration of battery output characteristics such as polymerization reaction of solvent molecules are likely to occur. . Therefore, in the non-aqueous electrolyte secondary battery in which the insulating porous layer is incorporated as a separator or a separator member, the output characteristics are rather deteriorated.

  The Lewis acid peak area (Lewis acidity) per unit weight of the metal salt fine particles can be adjusted by adjusting the composition of the metal salt fine particles and the surface area (shape, particle size) of the metal salt fine particles. Further, the surface area of the metal salt fine particles can be adjusted according to the conditions for producing the metal salt fine particles (in the case of a pulverized product, the pulverization conditions).

  The metal salt fine particles contained in the insulating porous layer are composed of a metal salt. Only one type of metal salt fine particles may be used, or two or more types of metal salt fine particles having different particle diameters and specific surface areas may be used in combination.

  The shape of the metal salt fine particles varies depending on the method for producing the metal salt as a raw material, the dispersion conditions of the metal salt fine particles when preparing a coating liquid for forming a porous layer, which will be described later, Various shapes such as an oval shape, a short shape, a bowl shape, or an indefinite shape having no specific shape can be used.

  The volume-based particle size distribution of the metal salt fine particles has two peak tops, the particle size of the first peak top is 0.4 μm or more and 0.6 μm or less, and the particle size of the second peak top is 5 μm or more. Preferably, the integrated distribution of the first peak top (under the sieve) is 10% or more and 20% or less, and the integrated distribution of the second peak top (under the sieve) is 60% or more and 80%. More preferably, it is more than that.

  The metal salt fine particles are preferably a pulverized product, and more preferably a pulverized product having an average particle size and a particle size distribution in the above-described ranges. The method for forming the metal salt fine particles into a pulverized product may be wet pulverization or dry pulverization. The specific method for obtaining the pulverized product is not particularly limited, for example, using a high-speed rotary mill, a rolling mill, a vibration mill, a planetary mill, a medium stirring mill, an airflow pulverizer, etc. For example, a coarse filler is pulverized. Among them, a dry pulverization method that does not use a dispersion medium is preferable, and a dry pulverization method in an apparatus using a pulverization medium such as a bead mill or a vibration ball mill is more preferable. In addition, the Mohs hardness of the pulverization medium is the metal salt. It is particularly preferable that the Mohs' hardness is equal to or higher than that. As the pulverization method, a medialess pulverization method in which the collision between the ceramic particles and the media does not occur, for example, a method in which a jet flow described in Japanese Patent No. 4781263 is combined with high-speed shearing by a rotating blade is used. You can also

  Although the metal salt which comprises the said metal salt microparticles | fine-particles is not specifically limited, Preferably it is an inorganic substance, More preferably, they are a metal carbonate and a metal oxide. Specifically, alkali metal carbonates such as lithium carbonate and sodium carbonate; alkaline earth metal carbonates such as calcium carbonate and barium carbonate; magnesium carbonate; titanium oxide, alumina, boehmite (alumina monohydrate), zirconia And metal oxides such as silica, magnesia, calcium oxide, barium oxide, boron oxide and zinc oxide. In addition, the metal oxide may be a composite oxide, and at least one element selected from an aluminum element, a titanium element, a zirconium element, a silicon element, a boron element, a magnesium element, a calcium element, and a barium element as a constituent metal element It is preferable that it contains, and it is further more preferable that aluminum element and titanium element are included. The metal salt preferably contains alumina, titanium oxide, lithium carbonate, calcium carbonate, or magnesium carbonate, and particularly preferably contains alumina and titanium oxide.

  Furthermore, although only one type of the metal salt may be used, it is preferable to use two or more types. Among these, the metal salt preferably contains a titanium oxide, and more preferably contains an aluminum element and a titanium element. The metal salt fine particles may be fine particles composed of a mixture of two or more kinds of metal salts. The metal salt fine particles preferably contain a metal salt in the form of a solid solution, and more preferably consist only of a metal salt in the form of a solid solution. Specifically, the metal salt fine particles are particularly preferably fine particles made of a solid solution of alumina and titania.

  The insulating porous layer in the present invention is usually a resin layer containing a resin as a binder resin in addition to a filler made of a metal salt. The resin constituting the insulating porous layer is preferably insoluble in the battery electrolyte and is electrochemically stable in the range of use of the battery.

  Specific examples of the resin include polyolefins such as polyethylene, polypropylene, polybutene, and ethylene-propylene copolymers; fluorine-containing resins such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene; vinylidene fluoride-hexa Fluorinated rubber such as fluoropropylene-tetrafluoroethylene copolymer and ethylene-tetrafluoroethylene copolymer; aromatic polyamide; wholly aromatic polyamide (aramid resin); styrene-butadiene copolymer and its hydride, methacrylic acid Ester copolymers, acrylonitrile-acrylic acid ester copolymers, styrene-acrylic acid ester copolymers, rubbers such as ethylene propylene rubber and polyvinyl acetate; polyphenylene ether, polysulfone, polyether sulfone Polyphenylene sulfide, polyether imide, polyamide imide, polyether amide, polyester and other resins having a melting point or glass transition temperature of 180 ° C. or higher; polyvinyl alcohol, polyethylene glycol, cellulose ether, sodium alginate, polyacrylic acid, polyacrylamide, polymethacryl Examples thereof include water-soluble polymers such as acids.

  Specific examples of the aromatic polyamide include poly (paraphenylene terephthalamide), poly (metaphenylene isophthalamide), poly (parabenzamide), poly (metabenzamide), and poly (4,4 ′). -Benzanilide terephthalamide), poly (paraphenylene-4,4'-biphenylenedicarboxylic acid amide), poly (metaphenylene-4,4'-biphenylenedicarboxylic acid amide), poly (paraphenylene-2,6-naphthalenedicarboxylic acid) Acid amide), poly (metaphenylene-2,6-naphthalenedicarboxylic acid amide), poly (2-chloroparaphenylene terephthalamide), paraphenylene terephthalamide / 2,6-dichloroparaphenylene terephthalamide copolymer, metaphenylene Terephthalamide / 2 6-dichloro-para-phenylene terephthalamide copolymer and the like. Of these, poly (paraphenylene terephthalamide) is more preferable.

  Of the above resins, polyolefins, fluorine-containing resins, aromatic polyamides, and water-soluble polymers are more preferable. Above all, when the insulating porous layer is used as a separator in a non-aqueous electrolyte secondary battery, or when used as a member of a laminated separator for a non-aqueous electrolyte secondary battery, it is caused by oxidative deterioration during battery operation. Fluorine-containing resins are particularly preferable because various performances such as rate characteristics and resistance characteristics (liquid resistance) of the nonaqueous electrolyte secondary battery can be easily maintained. Since the water-soluble polymer can use water as a solvent when forming the insulating porous layer, it is more preferable from the viewpoint of process and environmental load, cellulose ether and sodium alginate are more preferable, and cellulose ether is particularly preferable.

  Specific examples of the cellulose ether include carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), carboxyethyl cellulose, methyl cellulose, ethyl cellulose, cyanethyl cellulose, oxyethyl cellulose, and the like, and there is little deterioration in use over a long period of time. CMC and HEC which are excellent in chemical stability are more preferable, and CMC is particularly preferable.

  When the insulating porous layer contains a resin in addition to the filler made of a metal salt, the filler content is preferably 1 to 99% by volume of the insulating porous layer, and is preferably 5 to 95. More preferably, it is volume%. By setting the content of the fine particles in the above range, voids formed by contact between the fine particles are less likely to be blocked by a resin or the like, and the insulating porous layer obtains sufficient ion permeability. And the basis weight per unit area can be set to an appropriate value.

The basis weight per unit area (per side) of the insulating porous layer may be appropriately determined in consideration of the strength, film thickness, weight, and handling properties of the insulating porous layer. Is used as a member of an insulating porous layer for a nonaqueous electrolyte secondary battery as a separator or a laminated separator for a nonaqueous electrolyte secondary battery, the weight energy density or volume energy density of the battery is increased. in terms usually it is preferably from 1 to 20 g / m ^2, and more preferably 2 to 10 g / m ^2. When the basis weight of the insulating porous layer exceeds the above range, the insulating porous layer is used as an insulating porous layer for a non-aqueous electrolyte secondary battery or a non-aqueous electrolyte secondary battery as a separator. When used as a member of a laminated separator, the nonaqueous electrolyte secondary battery including the insulating porous layer becomes heavy.

The porous layer component of the volume contained in the per square meter of the insulating porous layer (per one side) is preferably 0.5～20Cm ^3, more preferably 1 to 10 cm ^3, More preferably, it is 2-7 cm ³ . That is, component volume basis weight (per one surface) of the insulating porous layer is preferably 0.5~20cm ³ / m ^2, more preferably 1~10cm ³ / m ^2, 2~7cm ³ further preferably / m ^2. When the volume per unit volume of the insulating porous layer is less than 0.5 cm ³ / m ² , the insulating porous layer is used as a separator in a non-aqueous electrolyte secondary battery or a laminate for a non-aqueous electrolyte secondary battery. When used as a separator member, an internal short circuit due to damage or the like of the battery cannot be sufficiently prevented.

Here, the component volume basis weight is calculated using the following method.
(1) The basis weight of each component is calculated by multiplying the basis weight of the insulating porous layer by the weight concentration of each component constituting the insulating porous layer (weight concentration in the porous layer).
(2) The basis weight of each component obtained in (1) is divided by the true specific gravity of each component, and the sum of the obtained numerical values is defined as the component volume basis weight of the B layer.

In addition, when the component volume per unit area of the insulating porous layer exceeds 20 cm ³ / m ² , the lithium ion permeation resistance in the entire insulating porous layer increases, so that the non-insulating porous layer is included. In a water electrolyte secondary battery, when the cycle is repeated, the positive electrode deteriorates, and the rate characteristics and cycle characteristics of the battery deteriorate.

  The porosity of the insulating porous layer is preferably 20 to 90% by volume and more preferably 30 to 70% by volume so that sufficient ion permeability can be obtained. Further, the pore diameter of the pores of the insulating porous layer should be 3 μm or less so that the insulating porous layer can obtain sufficient ion permeability and particles that have fallen off from the electrode do not pass. Is preferable, and it is more preferable that it is 1 micrometer or less.

  The thickness of the insulating porous layer is usually 0.1 μm or more and 20 μm or less, preferably 2 μm or more and 15 μm or less. When the insulating porous layer is too thick (greater than 20 μm), when a non-aqueous electrolyte secondary battery including the insulating porous layer is manufactured, the internal resistance of the battery increases, and output characteristics On the other hand, if the insulating porous layer is too thin (less than 0.1 μm), the insulating property and the voltage leakage resistance of the insulating porous layer are reduced, and When the insulating porous layer is laminated on a polyolefin porous membrane and used as a member of a laminated separator for a non-aqueous electrolyte secondary battery, abnormal heat is generated in the non-aqueous electrolyte secondary battery including the laminated separator. When this occurs, the laminated separator may shrink without being able to resist the heat shrinkage of the polyolefin porous membrane. In addition, when an insulating porous layer is formed on both surfaces of a porous film (polyolefin porous film), the thickness of an insulating porous layer shall be the total thickness of both surfaces.

  As a method for producing an insulating porous layer in the present invention, the resin is dissolved in a solvent and the metal salt fine particles are dispersed to prepare a coating liquid for forming the insulating porous layer, An example is a method in which the coating liquid is applied onto a substrate, and then the insulating porous layer is deposited by removing the solvent. In addition, the said base material can be the electrode in a porous film which comprises the laminated separator for nonaqueous electrolyte secondary batteries mentioned later, or a nonaqueous electrolyte secondary battery, especially a positive electrode, for example.

  The solvent (dispersion medium) does not adversely affect the porous film or electrode as a substrate, and can dissolve the resin uniformly and stably and disperse the metal salt fine particles uniformly and stably. It is not limited. Specific examples of the solvent (dispersion medium) include water; lower alcohols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, and t-butyl alcohol; acetone, toluene, xylene, hexane, N -Methylpyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide and the like. The solvent (dispersion medium) may be used alone or in combination of two or more.

  The coating liquid can be formed by any method as long as it can satisfy conditions such as the resin solid content (resin concentration) and the amount of metal salt fine particles necessary to obtain a desired insulating porous layer. Good. Specific examples of the method for forming the coating liquid include a mechanical stirring method, an ultrasonic dispersion method, a high-pressure dispersion method, and a media dispersion method. Further, for example, a filler may be dispersed in a solvent (dispersion medium) using a conventionally known disperser such as a three-one motor, a homogenizer, a media type disperser, or a pressure disperser. Further, when the metal salt fine particles are prepared by a wet pulverization method, a wet pulverization method for obtaining a metal salt fine particle having a desired average particle diameter is obtained by dissolving or swelling a resin or a resin emulsion. Sometimes, the coating liquid can be prepared simultaneously with the wet pulverization of the metal salt fine particles by supplying it into the wet pulverization apparatus. That is, the wet pulverization of the metal salt fine particles and the preparation of the coating liquid may be performed simultaneously in one step. In addition, the coating liquid may contain additives such as a dispersant, a plasticizer, a surfactant, and a pH adjuster as components other than the resin and fine particles as long as the object of the present invention is not impaired. . In addition, the addition amount of an additive should just be a range which does not impair the objective of this invention.

  The method for applying the coating liquid to the substrate is not particularly limited. For example, in the case of laminating an insulating porous layer on both sides of a base material, after sequentially forming an insulating porous layer on one side of the base material, an insulating porous layer is formed on the other side. The method and the simultaneous lamination method which forms an insulating porous layer simultaneously on both surfaces of a base material can be performed. As a method for forming the insulating porous layer, for example, a method in which the coating liquid is directly applied to the surface of the substrate, and then the solvent (dispersion medium) is removed; the coating liquid is applied to an appropriate support, and the solvent (Dispersion medium) is removed to form an insulating porous layer, and then the insulating porous layer and the substrate are pressure-bonded, and then the support is peeled off; the coating liquid is applied to an appropriate support After that, the base material is pressure-bonded to the coated surface, and then the support (peeling) is removed, and then the solvent (dispersion medium) is removed; the base material is immersed in the coating liquid and dip-coated, and then the solvent (dispersion medium) And the like. The thickness of the insulating porous layer is the thickness of the coating film in a wet state (wet) after coating, the weight ratio between the resin and the fine particles, the solid content concentration of the coating liquid (the resin concentration and the fine particle concentration It can be controlled by adjusting the sum). In addition, as a support body, a resin film, a metal belt, a drum, etc. can be used, for example.

  The method for applying the coating liquid to the substrate or the support is not particularly limited as long as it is a method capable of realizing a necessary basis weight and coating area. As a coating method of the coating liquid, conventionally known methods can be employed. Specifically, for example, a gravure coater method, a small diameter gravure coater method, a reverse roll coater method, a transfer roll coater method, a kiss coater method, a dip coater method, Examples include a coater method, a knife coater method, an air doctor blade coater method, a blade coater method, a rod coater method, a squeeze coater method, a cast coater method, a bar coater method, a die coater method, a screen printing method, and a spray coating method.

  As a method for removing the solvent (dispersion medium), a drying method is generally used. Examples of the drying method include natural drying, air drying, heat drying, and drying under reduced pressure. Any method may be used as long as the solvent (dispersion medium) can be sufficiently removed. Further, the solvent (dispersion medium) contained in the coating liquid may be replaced with another solvent before drying. As a method for removing the solvent (dispersion medium) after replacing it with another solvent, for example, it is possible to dissolve in the solvent (dispersion medium) contained in the coating liquid and not dissolve the resin contained in the coating liquid. In the coating film on the substrate or the support, the substrate or the support on which the coating liquid is applied and the coating film is formed is immersed in the solvent X. A method of evaporating the solvent X after replacing the solvent (dispersion medium) with the solvent X can be mentioned. This method can efficiently remove the solvent (dispersion medium) from the coating solution. In addition, when using the porous film which has polyolefin as a main component as a base material, it is a solvent (dispersion medium) or solvent from the coating film of the coating liquid formed in the base material (the said porous film) or a support body. When performing heating when removing X, in order to avoid the pores of the porous film from shrinking and reducing the air permeability, a temperature at which the air permeability of the porous film does not decrease, specifically Is preferably performed at 10 to 120 ° C, more preferably 20 to 80 ° C. Moreover, a normal drying apparatus can be used for the said drying.

[Porous film]
The porous film in the non-aqueous electrolyte secondary battery laminated separator according to the present invention is a base material of the non-aqueous electrolyte secondary battery laminated separator, and has a large number of pores mainly composed of polyolefin and connected to the inside thereof. It is possible to pass gas or liquid from one surface to the other surface.

With the porous film which has polyolefin as a main component, the ratio of the polyolefin to the said porous film is 50 volume% or more of the said porous film whole, It is more preferable that it is 90 volume% or more, 95 volume% More preferably, it is the above. Moreover, 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 porous film and the laminate including the porous film, that is, the laminated separator for a nonaqueous electrolyte secondary battery is improved. Therefore, it is more preferable.

  Specific examples of the polyolefin that is a thermoplastic resin include, for example, a single copolymer obtained by (co) polymerizing monomers such as ethylene, propylene, 1-butene, 4-methyl-1-pentene, and 1-hexene. A polymer (for example, polyethylene, polypropylene, polybutene) or a copolymer (for example, ethylene-propylene copolymer) may be mentioned. Of these, polyethylene is more preferable because it can prevent (shut down) an excessive current from flowing at a lower temperature. Examples of the polyethylene include low density polyethylene, high density polyethylene, linear polyethylene (ethylene-α-olefin copolymer), ultrahigh molecular weight polyethylene having a weight average molecular weight of 1,000,000 or more, and of these, weight average molecular weight. Is more preferably an ultrahigh molecular weight polyethylene having 1 million or more.

  The film thickness of the porous film may be appropriately determined in consideration of the thickness of the laminated separator for nonaqueous electrolyte secondary batteries, but the porous film is used as a base material and insulated on one or both sides of the porous film. In the case of forming a laminated separator for a non-aqueous electrolyte secondary battery by laminating a porous porous layer, it is usually 4 to 50 μm, preferably 5 to 30 μm. When the film thickness of the porous film is less than 4 μm, the mechanical strength of the porous film becomes insufficient, and the porous film or the laminated separator for a non-aqueous electrolyte secondary battery including the porous film is assembled during battery assembly. May break, and the amount of the electrolyte retained in the porous film decreases, so that the battery long-term characteristics of the non-aqueous electrolyte secondary battery including the porous film decrease. On the other hand, if the film thickness of the porous film exceeds 50 μm, the lithium ion permeation resistance in the entire laminated separator for a non-aqueous electrolyte secondary battery including the porous film increases. Therefore, the non-aqueous electrolyte secondary battery In the non-aqueous electrolyte secondary battery having the laminated separator for use, the positive electrode deteriorates as the cycle is repeated, and the rate characteristics and cycle characteristics deteriorate. In addition, since the distance between the positive electrode and the negative electrode is increased, the nonaqueous electrolyte secondary battery is increased in size.

  The pore diameter of the porous film is preferably 3 μm or less, and more preferably 1 μm or less.

The basis weight per unit area of the porous film may be appropriately determined in consideration of the strength, film thickness, weight, and handleability of the non-aqueous electrolyte secondary battery laminated separator, but the non-aqueous electrolyte secondary In order to increase the weight energy density and volume energy density of the nonaqueous electrolyte secondary battery incorporating the battery separator, it is usually preferably 4 to ²⁰ g / m ² , and preferably 5 to 12 g / m. ² is more preferable.

  The air permeability of the porous film is preferably 30 to 500 sec / 100 mL, more preferably 50 to 300 sec / 100 mL in terms of Gurley value. When the porous film has the above air permeability, the laminated separator for a non-aqueous electrolyte secondary battery can obtain sufficient ion permeability.

  The porosity of the porous film should be 30 to 60% by volume so as to increase the amount of electrolyte retained and to obtain a function to reliably prevent (shut down) the flow of excessive current at a lower temperature. Is preferable, and it is more preferable that it is 35-55 volume%.

  When the porosity of the porous film is less than 30% by volume, the resistance of the porous film increases. Moreover, when the porosity of a porous film exceeds 60 volume%, the mechanical strength of the said porous film will fall.

  Moreover, the pore diameter of the porous film is such that the laminated separator for a non-aqueous electrolyte secondary battery can obtain sufficient ion permeability and prevents particles from entering the positive electrode and the negative electrode. Therefore, it is preferably 3 μm or less, and more preferably 1 μm or less.

  The method for producing the porous film is not particularly limited. For example, a method of adding a pore forming agent such as calcium carbonate to a resin such as polyolefin to form a film, and then removing the pore forming agent with an appropriate solvent. Is mentioned.

Specifically, for example, in the case of producing a porous film using a polyolefin resin containing ultrahigh molecular weight polyethylene and a low molecular weight polyolefin having a weight average molecular weight of 10,000 or less, from the viewpoint of production cost, It is preferable to produce the porous film by the method shown.
(1) 100 parts by weight of ultra high molecular weight polyethylene, 5 to 200 parts by weight of a low molecular weight polyolefin having a weight average molecular weight of 10,000 or less, and 100 to 400 parts by weight of an inorganic filler such as calcium carbonate are kneaded to prepare a polyolefin resin composition Obtaining a product,
(2) A step of forming a sheet using the polyolefin resin composition,
Then
(3) a step of removing the inorganic filler from the sheet obtained in step (2),
(4) A step of stretching the sheet from which the inorganic filler has been removed in step (3) to obtain a porous film.
Or
(3 ′) a step of stretching the sheet obtained in step (2),
(4 ′) A step of removing the inorganic filler from the sheet stretched in the step (3 ′) to obtain a porous film.

  In addition, the commercial item which has the physical property mentioned above can also be used for a porous film.

  In addition, it is more preferable that the porous film is subjected to a hydrophilic treatment before the insulating porous layer is formed, that is, before the coating liquid described later is applied. By applying a hydrophilic treatment to the porous film, the coating property of the coating liquid is further improved, and therefore a more uniform insulating porous layer can be formed. This hydrophilization treatment is effective when the proportion of water in the solvent (dispersion medium) contained in the coating liquid is high. Specific examples of the hydrophilic treatment include known treatments such as chemical treatment with acid or alkali, corona treatment, plasma treatment and the like. Among the above hydrophilization treatments, the porous film can be hydrophilized in a relatively short time, and since the hydrophilization is limited only to the vicinity of the surface of the porous film, the inside of the porous film is not altered, Corona treatment is more preferred.

[Method for producing laminated separator for non-aqueous electrolyte secondary battery]
As a manufacturing method of the non-aqueous-electrolyte secondary battery laminated separator of this invention, the method which uses a base material as the above-mentioned porous film in the manufacturing method of the above-mentioned insulating porous layer can be mentioned.

  Furthermore, the thickness (film thickness) of the laminated separator for a non-aqueous electrolyte secondary battery of the present invention is usually 5 to 80 μm, preferably 5 to 50 μm, and particularly preferably 6 to 35 μm. When the total thickness of the separator is less than 5 μm, the separator easily breaks, and when it exceeds 80 μm, the internal resistance of the non-aqueous electrolyte secondary battery including the separator increases, and the output characteristics, etc. When the battery characteristics deteriorate and the internal volume of the battery is small, the amount of electrodes must be reduced, and as a result, the battery capacity of the battery becomes small.

[Embodiment 3: Nonaqueous electrolyte secondary battery member, Embodiment 4: Nonaqueous electrolyte secondary battery]
A member for a non-aqueous electrolyte secondary battery according to Embodiment 3 of the present invention is a non-aqueous electrolyte secondary battery in which a positive electrode, an insulating porous layer according to Embodiment 1 of the present invention, and a negative electrode are arranged in this order. It may be a member for a secondary battery. Further, the member for a nonaqueous electrolyte secondary battery according to Embodiment 3 of the present invention includes a positive electrode, a laminated separator for a nonaqueous electrolyte secondary battery according to Embodiment 2 of the present invention, and a negative electrode arranged in this order. It can also be a member for a non-aqueous electrolyte secondary battery.

  The member for a non-aqueous electrolyte secondary battery of the present invention is an insulating porous material including a metal salt fine particle whose Lewis acid peak area per unit weight (Lewis acidity) is controlled within a specific range as a separator or a member of a separator. Provide a quality layer. Therefore, the output characteristic of the nonaqueous electrolyte secondary battery incorporating the nonaqueous electrolyte secondary battery member can be improved.

  The nonaqueous electrolyte secondary battery according to Embodiment 4 of the present invention includes the insulating porous layer according to Embodiment 1 of the present invention or the laminated separator for a nonaqueous electrolyte secondary battery according to Embodiment 2 of the present invention. Including. The non-aqueous electrolyte secondary battery includes a positive electrode, a negative electrode, and an electrolyte as members other than the insulating porous layer or the laminated separator for non-aqueous electrolyte secondary batteries.

  The nonaqueous electrolyte secondary battery of the present invention includes a porous layer containing metal salt fine particles whose Lewis acid peak area per unit weight (Lewis acidity) is controlled in a specific range as a separator or a member of the separator. . Therefore, the non-aqueous electrolyte secondary battery is excellent in output characteristics.

  Hereinafter, as the non-aqueous electrolyte secondary battery, each member will be described by taking a lithium ion secondary battery as an example. In the nonaqueous electrolyte secondary battery member and the nonaqueous electrolyte secondary battery of the present invention, the non-aqueous electrolyte secondary battery insulating porous layer and the nonaqueous electrolyte secondary battery laminated separator are: It is the insulating porous layer for non-aqueous electrolyte secondary batteries of the present invention described above, and the laminated separator for non-aqueous electrolyte secondary batteries. The constituent elements of the nonaqueous electrolyte secondary battery other than the insulating porous layer for the nonaqueous electrolyte secondary battery and the laminated separator for the nonaqueous electrolyte secondary battery are limited to the constituent elements described below. is not.

[Electrolyte]
As the electrolyte in the non-aqueous electrolyte secondary battery of the present invention, for example, a non-aqueous electrolyte obtained by dissolving a lithium salt in an organic solvent that is an electrolyte solvent can be used. Examples of the lithium salt include 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 , Li ₂ B ₁₀ Cl. _10. Lower aliphatic carboxylic acid lithium salt, LiAlCl _{4 and the} like. The lithium salt may be used alone or in combination of two or more. Among the lithium salts, at least one selected from the group consisting of LiPF ₆ , LiAsF ₆ , LiSbF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , and LiC (CF ₃ SO ₂ ) _3. More preferred are fluorine-containing lithium salts.

  Although it does not specifically limit as electrolyte solution solvent, For example, ethylene carbonate (EC), propylene carbonate (PMC), dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), 4 -Carbonates such as trifluoromethyl-1,3-dioxolan-2-one, 1,2-di (methoxycarbonyloxy) ethane; 1,2-dimethoxyethane, 1,3-dimethoxypropane, pentafluoropropyl methyl ether , 2,2,3,3-tetrafluoropropyldifluoromethyl ether, ethers such as tetrahydrofuran and 2-methyltetrahydrofuran; esters such as methyl formate, methyl acetate and γ-butyrolactone; nitriles such as acetonitrile and butyronitrile Amides such as N, N-dimethylformamide and N, N-dimethylacetamide; carbamates such as 3-methyl-2-oxazolidone; sulfur-containing compounds such as sulfolane, dimethyl sulfoxide and 1,3-propane sultone; And a fluorine-containing organic solvent obtained by introducing a fluorine group into the organic solvent. Only one kind of the organic solvent may be used, or two or more kinds may be used in combination. Among the organic solvents, carbonates are more preferable, and a mixed solvent of cyclic carbonate and acyclic carbonate, or a mixed solvent of cyclic carbonate and ethers is more preferable. As a mixed solvent of cyclic carbonate and non-cyclic carbonate, ethylene carbonate has a wide operating temperature range and is difficult to decompose even when a graphite material such as natural graphite or artificial graphite is used as the negative electrode active material. More preferred is a mixed solvent containing dimethyl carbonate and ethyl methyl carbonate.

[Positive electrode]
As the positive electrode, a positive electrode generally used in a nonaqueous electrolyte secondary battery can be used. For example, a positive electrode mixture containing a positive electrode active material, a conductive material, and a binder is supported on a positive electrode current collector. A sheet-like positive electrode is used.

Examples of the positive electrode active material include materials that can be doped / undoped with lithium ions. Specific examples of the material include lithium composite oxides containing at least one transition metal such as V, Mn, Fe, Co, and Ni. Among the lithium composite oxides, since the average discharge potential is high, lithium composite oxides having an α-NaFeO ₂ type structure such as lithium nickelate and lithium cobaltate, and lithium composites having a spinel type structure such as lithium manganese spinel Oxides are more preferred. The lithium composite oxide may contain various metal elements, and composite lithium nickelate is more preferable.

  Furthermore, the number of moles of at least one metal element selected from the group consisting of Ti, Zr, Ce, Y, V, Cr, Mn, Fe, Co, Cu, Ag, Mg, Al, Ga, In, and Sn When using the composite lithium nickelate containing the metal element so that the ratio of the at least one metal element is 0.1 to 20 mol% with respect to the sum of the number of moles of Ni in the lithium nickelate, This is particularly preferable because of excellent cycle characteristics in use at a high capacity. Among them, an active material containing Al or Mn and having a Ni ratio of 85% or more, more preferably 90% or more is used in a high capacity of a non-aqueous electrolyte secondary battery including a positive electrode containing the active material. Since it is excellent in cycling characteristics, it is especially preferable.

  Examples of the conductive material include carbonaceous materials such as natural graphite, artificial graphite, cokes, carbon black, pyrolytic carbons, carbon fibers, and fired organic polymer compounds. Only one type of the conductive material may be used. For example, two or more types may be used in combination, such as a mixture of artificial graphite and carbon black.

  Examples of the binder include polyvinylidene fluoride, vinylidene fluoride copolymer, polytetrafluoroethylene, tetrafluoroethylene-hexafluoropropylene copolymer, and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer. , Ethylene-tetrafluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene copolymer, thermoplastic resins such as thermoplastic polyimide, polyethylene, and polypropylene, acrylic resin, and styrene-butadiene rubber Can be mentioned. The binder also has a function as a thickener.

  As a method for obtaining the positive electrode mixture, for example, a method of obtaining a positive electrode mixture by pressurizing a positive electrode active material, a conductive material and a binder on a positive electrode current collector; a positive electrode active material, a conductive material using an appropriate organic solvent And a method of obtaining a positive electrode mixture by pasting a material and a binder.

  Examples of the positive electrode current collector include conductors such as Al, Ni, and stainless steel, and Al is more preferable because it is easily processed into a thin film and is inexpensive.

  As a method for producing a sheet-like positive electrode, that is, a method of loading a positive electrode mixture on a positive electrode current collector, for example, a positive electrode active material, a conductive material, and a binder as a positive electrode mixture are added on the positive electrode current collector. Method of pressure molding: After a positive electrode active material, a conductive material and a binder are pasted using an appropriate organic solvent to obtain a positive electrode mixture, the positive electrode mixture is applied to the positive electrode current collector and dried. And a method of pressurizing the obtained sheet-like positive electrode mixture and fixing it to the positive electrode current collector.

[Negative electrode]
As the negative electrode, a negative electrode generally used in a non-aqueous electrolyte secondary battery can be used. For example, a sheet-shaped negative electrode in which a negative electrode mixture containing a negative electrode active material is supported on a negative electrode current collector is used. It is done. The sheet-like negative electrode preferably contains the conductive material and the binder.

  Examples of the negative electrode active material include materials that can be doped / undoped with lithium ions, lithium metal, and lithium alloys. Specific examples of the material include carbonaceous materials such as natural graphite, artificial graphite, cokes, carbon black, pyrolytic carbons, carbon fibers, and fired organic polymer compounds; And chalcogen compounds such as oxides and sulfides that dope and dedope lithium ions. Among the negative electrode active materials, the potential flatness is high, and since the average discharge potential is low, a large energy density can be obtained when combined with the positive electrode. Therefore, the main component is a graphite material such as natural graphite or artificial graphite. A carbonaceous material is more preferable.

  As a method for obtaining the negative electrode mixture, for example, a method in which the negative electrode active material is pressurized on the negative electrode current collector to obtain the negative electrode mixture; the negative electrode active material is pasted into a paste using an appropriate organic solvent. And the like.

  Examples of the negative electrode current collector include Cu, Ni, stainless steel, and the like. In particular, in a lithium ion secondary battery, it is difficult to form an alloy with lithium, and Cu is more preferable because it is easy to process into a thin film.

  As a method for producing a sheet-like negative electrode, that is, a method of supporting the negative electrode mixture on the negative electrode current collector, for example, a method in which a negative electrode active material to be the negative electrode mixture is pressure-molded on the negative electrode current collector; After the negative electrode active material is made into a paste using an organic solvent to obtain a negative electrode mixture, the negative electrode mixture is applied to the negative electrode current collector and dried to press the sheet-like negative electrode mixture. And a method of fixing to the negative electrode current collector. The paste preferably contains the conductive assistant and the binder.

[Nonaqueous Electrolyte Secondary Battery Member, Nonaqueous Electrolyte Secondary Battery Manufacturing Method]
As a method for producing the non-aqueous electrolyte secondary battery member of the present invention, the positive electrode, the insulating porous layer for the non-aqueous electrolyte secondary battery of the present invention, or the non-aqueous electrolyte secondary battery of the present invention is used. A method of forming a member for a nonaqueous electrolyte secondary battery by arranging a laminated separator and a negative electrode in this order can be mentioned.

  Moreover, as a method for producing the nonaqueous electrolyte secondary battery of the present invention, for example, the positive electrode, the insulating porous layer for a nonaqueous electrolyte secondary battery, or the laminated separator for a nonaqueous electrolyte secondary battery and a negative electrode are used. After the non-aqueous electrolyte secondary battery member is formed by arranging in this order, the non-aqueous electrolyte secondary battery member is put in a container serving as a casing of the non-aqueous electrolyte secondary battery, After filling the container with a non-aqueous electrolyte, the non-aqueous electrolyte secondary battery according to the present invention can be manufactured by sealing the container while reducing the pressure. The shape of the non-aqueous electrolyte secondary battery is not particularly limited, and may be any shape such as a thin plate (paper) type, a disc type, a cylindrical type, and a rectangular column type such as a rectangular parallelepiped. In addition, the manufacturing method of the member for nonaqueous electrolyte secondary batteries of this invention and the manufacturing method of a nonaqueous electrolyte secondary battery are not specifically limited, A conventionally well-known manufacturing method is employable.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

  Hereinafter, although an example and a comparative example explain the present invention still in detail, the present invention is not limited to these examples.

[Measuring method]
Properties of non-aqueous electrolyte secondary battery laminated separators (laminated porous film), A layer (porous film), and B layer (insulating porous layer) prepared in Examples and Comparative Examples, and The discharge output characteristics (rate characteristics) of the nonaqueous electrolyte secondary battery were measured by the following method.

(1) Film thickness (unit: μm)
The film thickness of the laminated porous film (that is, the total film thickness), the film thickness of the A layer, and the film thickness of the B layer are measured using a high-precision digital length measuring machine (VL-50) manufactured by Mitutoyo Corporation. did.

(2) Weight per unit (unit: g / m ² )
From the laminated porous film, a square with a side length of 8 cm was cut out as a sample, and the weight W (g) of the sample was measured. And the following formula basis weight (g / m ² ) = W / (0.08 × 0.08)
Thus, the basis weight of the laminated porous film (that is, the overall basis weight) was calculated. Similarly, the basis weight of the A layer was calculated. The basis weight of the B layer was calculated by subtracting the basis weight of the A layer from the overall basis weight.

(3) Average particle size, particle size distribution (D10, D50, D90 (volume basis)) (unit: μm)
The particle size and particle size distribution of the filler were measured using MICROTRAC (MODEL: MT-3300EXII) manufactured by JGC.

(4) Quantification of Lewis Acidity of Metal Salt Fine Particles According to the flow shown in FIG. 1, the Lewis acid peak area (Lewis acidity) per unit weight of the metal salt fine particles produced in Examples and Comparative Examples was measured. .

First, 40 mg of metal salt fine particles are weighed and formed into a disk-shaped pellet. The pellet is placed in a heat-transmitting in-situ cell at room temperature, evacuated, and then the temperature inside the cell is set to 500. The temperature was raised to 0 ° C. and the temperature was maintained for 60 minutes. After cooling to 30 ° C., using a Nicolet Co. Fourier transform infrared spectrophotometer Avatar 360, resolution 4 cm ^-1, cumulated number 256, under the conditions of the measurement region wavenumber 4000cm ^-1 ~400cm ^-1, infrared A transmission spectrum was measured (Measurement 1). The obtained spectrum was used as the background spectrum.

  Subsequently, the temperature inside the cell is raised to 100 ° C., pyridine vapor is introduced into the cell, and pyridine is adsorbed on the pellets over 5 minutes. Thereafter, the temperature inside the cell is raised to 150 ° C., and the temperature is maintained for 60 minutes to desorb the physically adsorbed pyridine from the pellet made of the metal salt fine particles, and then the temperature inside the cell Was reduced to 30 ° C., and the infrared transmission spectrum of the sample after the pyridine was adsorbed and desorbed was measured under the same conditions as those for measuring the infrared transmission spectrum described above (Measurement 2).

Thereafter, based on the two infrared transmission spectra measured, the peak area existing in the region from 1447 to 1460 cm ⁻¹ , which is a peak derived from Lewis acid, was calculated. That is, after obtaining the infrared absorption spectrum by subtracting the background infrared transmission spectrum from the infrared transmission spectrum after pyridine is adsorbed and desorbed, the base is obtained from both ends of the peak existing in the region from 1447 to 1460 cm ^−1. A line was drawn and the area surrounded by the base line and the peak was defined as the peak area. The peak area per unit weight of the metal salt was calculated by dividing the peak area by the weight of the metal salt (40 mg).

(6) Rate characteristics (%)
For non-aqueous electrolyte secondary batteries fabricated in Examples and Comparative Examples, voltage range at 25 ° C .; 4.1 to 2.7 V, current value: 0.2 C (rated by discharge capacity at 1 hour rate) 4 cycles of initial charge / discharge were carried out, assuming that the current value for discharging the capacity in 1 hour was 1 C, and so on).

  After the initial charge / discharge, the non-aqueous electrolyte secondary battery is charged / discharged at a cycle of 55 ° C., a charge current value of 1 C, and a constant current of 1 C and a discharge current value of 0.2 C and 20 C, respectively. The discharge capacity in each case was measured.

  The discharge capacity at the third cycle at discharge current values of 0.2 C and 20 C, respectively, was taken as the measured value of the discharge capacity. The ratio of the measured value (20C discharge capacity / 0.2C discharge capacity) was defined as the rate characteristic (%).

[Example 1]
<A layer>
The porous film which is a base material was produced using polyethylene which is polyolefin.

  That is, 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 (FNP-0115, manufactured by Nippon Seiki Co., Ltd.) having a weight average molecular weight of 1000 are mixed to form mixed polyethylene. Got. 0.4 parts by weight of antioxidant (Irg1010, manufactured by Ciba Specialty Chemicals Co., Ltd.) and antioxidant (P168, manufactured by Ciba Specialty Chemicals Co., Ltd.) with respect to 100 parts by weight of the obtained mixed polyethylene. 1 part by weight and 1.3 parts by weight of sodium stearate are added, and calcium carbonate (manufactured by Maruo Calcium Co., Ltd.) having an average particle size of 0.1 μm is added so that the ratio to the total volume is 38% by volume. It was. The composition was mixed with a Henschel mixer in the form of a powder, and then melt-kneaded with a biaxial kneader to obtain a polyethylene resin composition. Subsequently, this polyethylene resin composition was rolled with a pair of rolls having a surface temperature set to 150 ° C., thereby producing a sheet. The sheet was immersed in an aqueous hydrochloric acid solution (containing 4 mol / L hydrochloric acid and 0.5% by weight of a nonionic surfactant) to dissolve and remove calcium carbonate. Then, the said sheet | seat was extended 6 times at 105 degreeC, and the porous film (A layer) made from polyethylene was produced.

<Preparation of layer B>
(Preparation of metal salt fine particles)
As the metal salt, Aluminumoxid / Titandioxid (Al ₂ O ₃ / TiO ₂ = 60/40, solid solution) manufactured by Ceram was used. This metal salt was subjected to vibration mill pulverization using a 3.3 L alumina pot and 15 mmφ alumina balls for 4 hours to obtain metal salt fine particles.

(Preparation of coating solution)
The metal salt fine particles, vinylidene fluoride-hexafluoropropylene copolymer (manufactured by Arkema Co., Ltd .; trade name “KYNAR2801”) as a binder resin, and N-methyl-2-pyrrolidinone (manufactured by Kanto Chemical Co., Ltd.) as a solvent are as follows: Were mixed in the following manner.

  In the mixing mode, 10 parts by weight of vinylidene fluoride-hexafluoropropylene copolymer was added to 90 parts by weight of the metal salt fine particles to obtain a mixture. The above-mentioned solvent was added to the obtained mixture so that the concentration of solid content (metal salt fine particles + vinylidene fluoride-hexafluoropropylene copolymer) was 40% by weight to obtain a mixed solution. The obtained mixed liquid was stirred and mixed with a thin film swirl type high speed mixer (Filmics (registered trademark) manufactured by Primix Co., Ltd.) to obtain a uniform coating liquid 1.

<Preparation of laminated separator for nonaqueous electrolyte secondary battery (laminated porous film)>
The coating liquid 1 obtained on one side of the A layer was applied by a doctor blade method, and the resulting coating film was heated to 85 ° C. using a draft dryer (Tokyo Rika Kikai Co., Ltd., model: WFO-601SD). B layer was formed by drying. Thereby, the laminated porous film 1 in which the B layer was laminated on one side of the A layer was obtained.

<Measurement of properties of non-aqueous electrolyte secondary battery laminated separator, porous film, insulating porous layer>
Using the measurement method described above, the Lewis acid peak area per unit weight of the metal salt fine particles, the obtained laminated porous film 1, and the porous film (A layer) constituting the same, the insulating porous layer (B The physical properties of the layer) were measured. Table 1 shows the values of the Lewis acid peak areas per unit weight of the resulting metal salt fine particles.

<Production of non-aqueous electrolyte secondary battery>
Using the positive electrode and negative electrode shown below and the laminated porous film 1 described above, a non-aqueous electrolyte secondary battery was produced by the assembly method shown below.

(Positive electrode)
A commercially available positive electrode manufactured by applying LiNi _0.5 Mn _0.3 Co _0.2 O ₂ / conductive material / PVDF (weight ratio 92/5/3) to an aluminum foil was used. Cut the aluminum foil so that the size of the positive electrode active material layer formed on the positive electrode is 45 mm × 30 mm and the outer periphery has a width of 13 mm and no positive electrode active material layer formed. A positive electrode was obtained. The positive electrode active material layer had a thickness of 58 μm, a density of 2.50 g / cm ³ , and a positive electrode capacity of 174 mAh / g.

(Negative electrode)
A commercially available negative electrode produced by applying graphite / styrene-1,3-butadiene copolymer / sodium carboxymethylcellulose (weight ratio 98/1/1) to a copper foil was used. Cut off the copper foil from the negative electrode so that the size of the portion where the negative electrode active material layer is formed is 50 mm × 35 mm and the outer periphery thereof has a width of 13 mm and no negative electrode active material layer is formed. A negative electrode was obtained. The thickness of the negative electrode active material layer was 49 μm, the density was 1.40 g / cm ³ , and the negative electrode capacity was 372 mAh / g.

(Assembly method)
By laminating (arranging) the positive electrode, the laminated porous film 1 and the negative electrode in this order in a laminate pouch, a member 1 for a non-aqueous electrolyte secondary battery was obtained. At this time, the positive electrode and the negative electrode were disposed so 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 (overlaid on the main surface).

Subsequently, the non-aqueous electrolyte secondary battery member 1 was put in a bag in which an aluminum layer and a heat seal layer were laminated, and 0.25 mL of the non-aqueous electrolyte was put in this bag. As the non-aqueous electrolyte, an electrolyte at 25 ° C. in which LiPF ₆ having a concentration of 1.0 mol / liter is dissolved in a mixed solvent having a volume ratio of ethyl methyl carbonate, diethyl carbonate and ethylene carbonate of 50:20:30. Using. And the non-aqueous-electrolyte secondary battery 1 was produced by heat-sealing the said bag, decompressing the inside of a bag. The design capacity of the non-aqueous electrolyte secondary battery 1 was 20.5 mAh.
<Measurement of physical properties of non-aqueous electrolyte secondary battery>
With respect to the produced non-aqueous electrolyte secondary battery 1, the rate characteristic (%) was measured using the above-described method for measuring the rate characteristic. The results are shown in Table 1.

[Example 2]
As a metal salt, Aluminumoxid / Titandioxid (Al ₂ O ₃ / TiO ₂ = 85/15, solid solution) is used in place of Ceram's Aluminumoxid / Titandioxid (Al ₂ O ₃ / TiO ₂ = 60/40, solid solution). In the same manner as in Example 1, a laminated porous film 2, a non-aqueous electrolyte secondary battery member 2, and a non-aqueous secondary battery 2 were obtained. Moreover, each physical property was measured by the same method as Example 1. The results are shown in Table 1.

[Example 3]
As a metal salt, Aluminumoxid / Titandioxid (Al ₂ O ₃ / TiO ₂ = 99/1, solid solution) is used in place of Ceram's Aluminumoxid / Titandioxid (Al ₂ O ₃ / TiO ₂ = 60/40, solid solution). In the same manner as in Example 1, a laminated porous film 3, a non-aqueous electrolyte secondary battery member 3, and a non-aqueous secondary battery 3 were obtained. Moreover, each physical property was measured by the same method as Example 1. The results are shown in Table 1.

[Example 4]
As a metal salt, instead of Ceram's Aluminumoxid / Titandioxid (Al ₂ O ₃ / TiO ₂ = 60/40, solid solution), Al ₂ O ₃ and MgCO ₃ are mixed at a weight ratio of 99: 1. A laminated porous film 4, a nonaqueous electrolyte secondary battery member 4, and a nonaqueous secondary battery 4 were obtained in the same manner as in Example 1 except that the resulting metal salt mixture was used. Moreover, each physical property was measured by the same method as Example 1. The results are shown in Table 1.

[Comparative Example 1]
As a metal salt, instead of Ceram's Aluminumoxid / Titandioxid (Al ₂ O ₃ / TiO ₂ = 60/40, solid solution), magnesium oxide (manufactured by Kyowa Chemical Industry Co., Ltd .; trade name Pyroxuma (registered trademark) 500-04R) A laminated porous film 5, a non-aqueous electrolyte secondary battery member 5, and a non-aqueous secondary battery 5 were obtained in the same manner as in Example 1 except that. Moreover, each physical property was measured by the same method as Example 1. The results are shown in Table 1.

[Comparative Example 2]
Example 1 except that high purity alumina (trade name AA-03 manufactured by Sumitomo Chemical Co., Ltd.) is used instead of Ceram's Aluminumoxid / Titandioxid (Al ₂ O ₃ / TiO ₂ = 60/40, solid solution) as the metal salt. Similarly, a laminated porous film 6, a nonaqueous electrolyte secondary battery member 6, and a nonaqueous secondary battery 6 were obtained. Moreover, each physical property was measured by the same method as Example 1. The results are shown in Table 1.

[Comparative Example 3]
The laminated porous material was the same as in Example 1 except that magnesium carbonate was used as the metal salt instead of Ceram's Aluminumoxid / Titandioxid (Al ₂ O ₃ / TiO ₂ = 60/40, solid solution). The film 7, the member 7 for nonaqueous electrolyte secondary batteries, and the nonaqueous secondary battery 7 were obtained. Moreover, each physical property was measured by the same method as Example 1. The results are shown in Table 1.

[Conclusion]
From the description of Table 1, it has a porous layer containing metal salt fine particles obtained in Examples 1 to 4 and having a Lewis acid peak area per unit weight in the range of 0.2 to 3.6. The non-aqueous electrolyte secondary battery laminated separator has a porous layer containing metal salt fine particles obtained in Comparative Examples 1 to 3 whose Lewis acid peak area per unit weight is outside the above range. It turned out that the discharge rate characteristic (discharge output characteristic) of a non-aqueous electrolyte secondary battery provided with the said separator is improved rather than the laminated separator for water electrolyte secondary batteries.

In addition, the improvement in the discharge rate characteristics described above can be achieved by appropriately adjusting the affinity between the metal salt fine particles and the electrolyte solvent in the porous layer of the multilayer separator for a non-aqueous electrolyte secondary battery. It is considered that this is because the progress of desolvation of (Li ⁺ ) is appropriately adjusted. Therefore, an insulating porous layer containing metal salt fine particles having a Lewis acid peak area per unit weight in the range of 0.2 to 3.6 is used alone as a separator for a non-aqueous electrolyte secondary battery. Even in the case, in the non-aqueous electrolyte secondary battery incorporating the insulating porous layer for a non-aqueous electrolyte secondary battery as a separator, the degree of progress of desolvation of cations (lithium ions) near the positive electrode, In addition, it is considered that the amount of side reactions such as generation of decomposition gas and polymerization of electrolyte solvent molecules that cause deterioration of battery characteristics is the same as in the case of the non-aqueous electrolyte secondary battery manufactured in the examples. Therefore, non-aqueous electrolyte secondary battery separators comprising an insulating porous layer containing metal salt fine particles having a Lewis acid peak area per unit weight in the range of 0.2 or more and 3.6 or less. It is considered that the insulating porous material for the water electrolyte secondary battery can also improve the output characteristics of the nonaqueous electrolytic solution secondary battery incorporating the insulating porous material for the nonaqueous electrolyte secondary battery.

  The insulating porous for non-aqueous electrolyte secondary battery of the present invention, the laminated separator for non-aqueous electrolyte secondary battery, and the member for non-aqueous electrolyte secondary battery are non-aqueous electrolyte secondary battery excellent in output characteristics. Can be used for manufacturing.

Claims (15)

Containing metal salt fine particles,
Was measured by infrared acidity Evaluation of the solid surface by spectroscopy, Lewis acid peak area per unit weight of the metal salt, 0.2 g ^-1 or more, 3.6 g ^-1 Ri der below,
Wherein the metal salt particle, characterized that you have include titanium oxide, a non-aqueous electrolyte secondary battery insulating porous membrane.
(Here, the Lewis acid peak area per unit weight of the metal salt is a peak existing in the region from 1447 to 1460 cm ⁻¹ in the infrared absorption (IR) spectrum measured from the sample after adsorption and desorption of pyridine. The peak area is divided by the weight of the metal salt used in the measurement.) The insulating porous layer for a nonaqueous electrolyte secondary battery according to claim 1, wherein the metal salt fine particles contain an aluminum element and a titanium element. Containing metal salt fine particles,
The Lewis acid peak area per unit weight of the metal salt, measured by infrared surface acid property evaluation method, was 0.2 g. ^-1 3.6g ^-1 And
An insulating porous layer for a non-aqueous electrolyte secondary battery, wherein the metal salt fine particles contain an aluminum element and a titanium element.
(Here, the Lewis acid peak area per unit weight of the metal salt is 1447 to 1460 cm in the infrared absorption (IR) spectrum measured from the sample after adsorption and desorption of pyridine. ^-1 It is a value obtained by dividing the peak area of the peak existing in the region by the weight of the metal salt used in the measurement. )   The insulating porous layer for a non-aqueous electrolyte secondary battery according to any one of claims 1 to 3, wherein the metal salt fine particles contain a metal salt in the form of a solid solution.   The insulating porous layer for a non-aqueous electrolyte secondary battery according to any one of claims 1 to 4, wherein the metal salt fine particles are a pulverized product.   The insulating porous layer for a non-aqueous electrolyte secondary battery according to any one of claims 1 to 5, wherein the metal salt fine particles are made of a mixture of two or more kinds of metal salts. A laminated separator for a non-aqueous electrolyte secondary battery in which an insulating porous layer is laminated on one or both sides of a porous film mainly composed of polyolefin,
The insulating porous layer includes metal salt fine particles,
Was measured by infrared acidity Evaluation of the solid surface by spectroscopy, Lewis acid peak area per unit weight of the metal salt, 0.2 g ^-1 or more, 3.6 g ^-1 Ri der below,
The insulating the porous layer, characterized that you have include metal salts particles containing titanium oxide, a non-aqueous electrolyte secondary battery stack separator.
(Here, the Lewis acid peak area per unit weight of the metal salt is a peak existing in the region from 1447 to 1460 cm ⁻¹ in the infrared absorption (IR) spectrum measured from the sample after adsorption and desorption of pyridine. The peak area is divided by the weight of the metal salt used in the measurement.) The multilayer separator for a nonaqueous electrolyte secondary battery according to claim 7, wherein the insulating porous layer contains metal salt fine particles containing an aluminum element and a titanium element. A laminated separator for a non-aqueous electrolyte secondary battery in which an insulating porous layer is laminated on one or both sides of a porous film mainly composed of polyolefin,
The insulating porous layer includes metal salt fine particles,
The Lewis acid peak area per unit weight of the metal salt, measured by infrared surface acid property evaluation method, was 0.2 g. ^-1 3.6g ^-1 And
A laminated separator for a nonaqueous electrolyte secondary battery, wherein the insulating porous layer contains metal salt fine particles containing an aluminum element and a titanium element.
(Here, the Lewis acid peak area per unit weight of the metal salt is 1447 to 1460 cm in the infrared absorption (IR) spectrum measured from the sample after adsorption and desorption of pyridine. ^-1 It is a value obtained by dividing the peak area of the peak existing in the region by the weight of the metal salt used in the measurement. )   The multilayer separator for a nonaqueous electrolyte secondary battery according to any one of claims 7 to 9, wherein the metal salt fine particles contain a metal salt in the form of a solid solution.   The multilayer separator for a nonaqueous electrolyte secondary battery according to any one of claims 7 to 10, wherein the metal salt fine particles are a pulverized product.   The laminated separator for a nonaqueous electrolyte secondary battery according to any one of claims 7 to 11, wherein the metal salt fine particles are composed of a mixture of two or more kinds of metal salts.   A positive electrode, an insulating porous layer for a non-aqueous electrolyte secondary battery according to any one of claims 1 to 6, and a negative electrode are arranged in this order. Secondary battery member.   A non-aqueous electrolyte secondary battery, wherein the positive electrode, the laminated separator for a non-aqueous electrolyte secondary battery according to any one of claims 7 to 12, and the negative electrode are arranged in this order. Element.   The insulating porous layer for a non-aqueous electrolyte secondary battery according to any one of claims 1 to 6 is contained as a separator or a member of the separator, or according to any one of claims 7 to 12. A non-aqueous electrolyte lithium ion secondary battery comprising: a non-aqueous electrolyte secondary battery laminated separator.

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