WO2021153652A1 - Separator for nonaqueous electrolyte batteries, method for producing same, nonaqueous electrolyte battery, and method for producing said nonaqueous electrolyte battery - Google Patents

Abstract

The present invention provides: a separator for constituting a nonaqueous electrolyte battery which has excellent safety and excellent reliability in terms of internal short circuit, while being able to be suppressed in deterioration of the characteristics at high temperatures; a method for producing this separator; a nonaqueous electrolyte battery which comprises this separator; and a method for producing this nonaqueous electrolyte battery.　A separator for nonaqueous electrolyte batteries according to the present invention is characterized in that: the separator comprises an inorganic particle layer that contains inorganic particles and a binder; the inorganic particle layer contains an amine compound (a) that is represented by general formula (1); the content of the binder in the inorganic particle layer is 2% by mass or more; and the content of the amine compound (a) is from 0.5% by mass to 7% by mass. (In the formula, R¹ represents –H or –C_xH_2xNH₂ (wherein x represents an integer from 2 to 6); R² represents –C_yH_2y- (wherein y represents an integer from 2 to 6); m represents an integer from 1 to 6; and in cases where m is 2 or more, the R¹ moieties may be different from each other.)

Description

Separator for non-aqueous electrolyte battery, its manufacturing method, non-aqueous electrolyte battery and its manufacturing method

The present invention relates to a separator for constructing a non-aqueous electrolyte battery which is excellent in safety and reliability against an internal short circuit and which can suppress deterioration of characteristics at high temperatures, a method for producing the same, and a non-aqueous electrolyte battery having the separator. It relates to the manufacturing method.

Non-aqueous electrolyte batteries represented by lithium secondary batteries are widely used as power sources for mobile devices and the like. Particularly in recent years, the application of non-aqueous electrolyte batteries to applications exposed to high temperatures has been progressing, and it is necessary to improve safety and reliability.

Further, in a non-aqueous electrolyte battery, a lithium-containing composite oxide containing a transition metal is generally used as a positive electrode active material, but in a non-aqueous electrolyte battery having such a positive electrode active material, a positive electrode is used particularly in a high temperature environment. Transition metal ions elute into the non-aqueous electrolyte and cause a decrease in the capacity of the positive electrode, eluted metal ions precipitate at the negative electrode and cause deterioration of the negative electrode, and react with the non-aqueous electrolyte to generate gas. As a result, the characteristics of the battery may be impaired.

On the other hand, technology is being developed to solve these problems. For example, Patent Document 1 discloses a separator containing fine particles having a specific average particle size in which a specific polyamine group having a function of trapping metal ions is fixed on the surface by surface treatment using a coupling agent. Therefore, a non-aqueous electrolyte battery has been proposed, which is excellent in safety and reliability against internal short circuits, and can suppress deterioration of characteristics during high-temperature storage.

Further, Patent Document 2 describes a separator in which heat shrinkage at a high temperature is suppressed, in which a coating layer containing a filler and a resin binder is provided on at least one surface of a polyolefin-based resin porous film. It is disclosed that by containing an adhesive such as an amine compound, the adhesion between the resin porous film and the coating layer can be improved, the content of the resin binder can be reduced, and a separator having excellent properties can be provided. Regarding the adhesive, Patent Document 2 describes an example using polyethyleneimine, and also exemplifies an amine compound containing a polyamine group described in Patent Document 1 such as polyalkylene polyamine. It is disclosed that the adhesive reacts with a polyolefin resin or a resin binder to enhance the adhesiveness.

Specifically, a polyolefin-based resin porous film contains a coating layer containing a filler (alumina) and a resin binder (polyvinyl alcohol) in a weight ratio of 39.4: 0.6 (98.5% by mass: 1.5% by mass). The peeling strength of the separator of Comparative Example 1 formed above was 0.9 (N / 15 mm), whereas the filler, the resin binder, and the adhesive (polyethylene imine) were added at 39.4: 0.6 :. Coating containing with a weight ratio of 0.003 to 0.6 (98.493% by mass: 1.500% by mass: 0.007% by weight to 97.0% by weight: 1.5% by mass: 1.5% by mass) The peeling strength of the separators of Examples 1 to 7 in which the layer was formed on the polyolefin-based resin porous film was 2.0 to 4.0 (N / 15 mm), and it was shown that the adhesiveness could be significantly improved.

Japanese Unexamined Patent Publication No. 2012-14994 International Publication No. 2012/42965

By the way, recently, the environment in which non-aqueous electrolyte batteries are applied has become more severe, and the application to applications such as automobile applications where the batteries are placed in a high temperature for a relatively long time is progressing. For example, in the separator described in Patent Document 1, in order to be able to trap a sufficient amount of metal ions even in such an application, it is conceivable to introduce more polyamine groups into the fine particles constituting the separator.

However, in the surface treatment with a coupling agent as described in Patent Document 1, the amount of polyamine groups that can be supported on the surface of the fine particles is limited, and not only the amount of ions that can be trapped is limited, but also the resin. It becomes a factor that hinders the binding property of the binder.

Further, as described in Patent Document 2, by incorporating an adhesive in the coating layer containing the filler and the resin binder, the adhesion between the resin porous film and the coating layer can be improved, and the adhesive can be improved. When is an amine compound, it is possible to retain many polyamine groups in the coating layer by adjusting the addition amount thereof.

However, when an amine compound having a specific structure is used as the adhesive, the binding action of the resin binder is hindered, the heat shrinkage of the separator is increased, and the safety and reliability of the battery at high temperatures are increased. It has been clarified by the examination by the present inventors that it is disadvantageous in terms of ensuring sex.

The present invention has been made in view of the above circumstances, and an object of the present invention is a separator for constructing a non-aqueous electrolyte battery which is excellent in safety and reliability against an internal short circuit and can suppress deterioration of characteristics at a high temperature. And a method for producing the same, and a non-aqueous electrolyte battery having the separator and a method for producing the same.

The separator for a non-aqueous electrolyte battery of the present invention has an inorganic particle layer containing inorganic particles and a binder, and the inorganic particle layer contains an amine compound (a) represented by the following general formula (1). The content of the binder in the inorganic particle layer is 2% by mass or more, and the content of the amine compound (a) is 0.5 to 7% by mass.

In the general formula (1), R ¹ : -H or -C _x H _2x NH ₂ (x is an integer of 2 to 6), R ² : -C _y H _2y- (y is 2 to 2 to 6). (An integer of 6), m is an integer of 1 to 6, and R ¹ may be different from each other when m is 2 or more.

In the method for producing a separator for a non-aqueous electrolyte battery of the present invention, a composition containing inorganic particles, a binder and an amine compound (a) represented by the general formula (1) is applied onto a resin microporous film or an electrode. The step of forming the inorganic particle layer on the film or the electrode is performed, and the ratio of the binder to the total amount of the inorganic particles, the binder and the amine compound (a) contained in the composition is 2% by mass. % Or more, and the proportion of the amine compound (a) is 0.5 to 7% by mass.

Further, in another aspect of the method for producing a separator for a non-aqueous electrolyte battery of the present invention, a composition containing inorganic particles and a binder is applied onto a resin microporous film or an electrode, and the composition is applied onto the film or the electrode. It has a step of forming an inorganic particle layer and a step of applying an amine compound on the inorganic particle layer, and the amine compound is an amine compound represented by the general formula (1) or the following general formula (2). An amine compound having a functional group and a hydrolyzing group represented by is used, and the coating amount of the amine compound is 0.03 to 0.7 g / m ^{2 per unit area of the inorganic particle layer.} And.

In the general formula (2), n is an integer of any of 2 to 6.

Further, the non-aqueous electrolyte battery of the present invention is characterized by having a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, and the non-aqueous electrolyte battery separator of the present invention is provided as the separator. Is to be.

Further, the method for manufacturing a non-aqueous electrolyte battery of the present invention is characterized in that a separator for a non-aqueous electrolyte battery manufactured by any of the above manufacturing methods is used as a separator.

According to the present invention, a separator for forming a non-aqueous electrolyte battery which is excellent in safety and reliability against an internal short circuit and can suppress deterioration of characteristics at a high temperature, a method for producing the same, and a non-aqueous electrolyte having the separator. A battery and a method for manufacturing the battery can be provided. That is, the non-aqueous electrolyte battery of the present invention and the non-aqueous electrolyte battery produced by the production method of the present invention are excellent in safety and reliability against internal short circuits, and can suppress deterioration of characteristics at high temperatures.

The separator described in Patent Document 1 includes, for example, a separator made of a porous film using fine particles containing a specific polyamine group and a binder, or a porous layer containing the fine particles and a binder made of polyolefin. It includes those made of a multilayer porous membrane formed on the surface of a porous substrate such as a porous membrane. In the separator described in Patent Document 1, the porous membrane itself containing the fine particles and the layer containing the fine particles do not easily shrink due to heat, and therefore the heat resistance of the separator is improved.

However, in the method described in Patent Document 1, since the proportion of polyamine groups that can be supported on the surface of the fine particles is limited, it is difficult not only to enhance the trapping function of metal ions, but also the fine particles are surface-treated with a coupling agent. As a result, the binding property of the binder used together with the fine particles is lowered, the porous layer containing the fine particles is easily heat-shrinked, and the heat resistance of the separator is higher than that when the fine particles not surface-treated are used. Decreases.

As for polyalkylene polyamine, as described above, Patent Document 2 is an adhesive that enhances the adhesion between the inorganic particle layer containing inorganic particles (filler) and binder and a porous substrate such as a microporous film made of polyolefin. Although it is illustrated in the above, it has been clarified by the studies by the present inventors that it actually has an action of impairing the adhesion between the inorganic particle layer and the porous substrate.

Therefore, the present inventors have made extensive studies, and while effectively exerting the metal ion trapping function of the specific amine compound, the configuration suppresses the deterioration of the adhesion between the inorganic particle layer and the porous base material or the electrode. By adopting the above, the present invention has been completed by making it possible to provide a non-aqueous electrolyte battery which is excellent in safety and reliability against internal short circuit and can suppress deterioration of characteristics at high temperature.

The separator for a non-aqueous electrolyte battery of the present invention (hereinafter, may be simply referred to as "separator") has an inorganic particle layer containing inorganic particles and a binder, and has a plurality of amino groups as a trapping agent for metal ions. A linear or branched amine compound having a structure in which the nitrogen atoms of the amino group are bonded to each other via a hydrocarbon chain having two or more carbon atoms is used.

Specifically, as the amine compound, the amine compound (a) represented by the following general formula (1) is used.

In the general formula (1), R ¹ : -H or -C _x H _2x NH ₂ (x is an integer of 2 to 6), R ² : -C _y H _2y- (y is 2 to 2 to 6). (An integer of 6), m is an integer of 1 to 6, and R ¹ may be different from each other when m is 2 or more.

Among the amine compounds (a), specific examples of the amine compound represented by the general formula (1) and having a linear structure include ethylenediamine (1,2-diaminoethane), 1,3-diaminopropane, and 1 , 4-Diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, diethylenetriamine, triethylenetotetramine, 3,3-diaminodipropylamine, tetraethylenepentamine and the like.

Among the amine compounds (a), specific examples of the amine compound represented by the general formula (1) and having a branched structure include tris (2-aminoethyl) amine.

Among the above-exemplified amine compounds, in addition to being difficult to reduce the adhesion between the inorganic particle layer and a porous base material such as a resin porous film or an electrode, the amount of adsorbed water in the separator can be suppressed to a low level. Since the water content brought into the battery using this can be reduced as much as possible, an amine compound having a linear structure is preferably used, and the number of carbon atoms of the hydrocarbon chain that bonds the nitrogen atoms of the amino group is high. More preferably, it is 2 or 3.

That is, in the general formula (1), R ^1: is preferably -H, more preferably x and y are each 2 or 3, diethylenetriamine, triethylenetetramine preparative tetramine, 3,3-diamino-dipropylamine Is even more preferable.

When m is 2 or more, a plurality of R ^1s may be different from each other, at least one may be −C _x H _{2 ×} NH ₂ , and the rest may be −H.

The amine compound (a) used in the separator has an excellent trapping function for metal ions, but when it is contained in a composition for forming an inorganic particle layer containing inorganic particles and a binder, it becomes an inorganic particle layer. Adhesion to the resin porous film or electrode tends to decrease. In addition, the binding property between the inorganic particles is also reduced.

Therefore, in the separator of the present invention, in order to prevent the amine compound (a) from inhibiting the binding action of the binder and to secure the adhesive strength between the inorganic particle layer and the resin porous film or the electrode, the above-mentioned The binder content in the inorganic particle layer is 2% by mass or more, and the content of the amine compound (a) is 7% by mass or less. Further, in order to impart an excellent trap function of metal ions to the inorganic particle layer, the content of the amine compound (a) in the inorganic particle layer is set to 0.5% by mass or more.

In the separator of the present invention, the binder content in the inorganic particle layer is 2% by mass or more, preferably 3% by mass or more, from the viewpoint of enhancing the heat resistance of the separator. However, if the amount of the binder in the inorganic particle layer is too large, it becomes difficult for lithium ions to pass through the separator, which may deteriorate the battery characteristics. Therefore, from the viewpoint of enabling the formation of a battery having better characteristics, the binder content in the inorganic particle layer is preferably 10% by mass or less, and more preferably 5% by mass or less.

Further, in order to prevent the amine compound (a) from inhibiting the binding action of the binder, the content of the amine compound (a) in the inorganic particle layer shall be 7% by mass or less and 5% by mass or less. Is preferable. On the other hand, from the viewpoint of improving the trapping function of metal ions, the amount of the amine compound (a) contained in the inorganic particle layer is preferably 0.5% by mass or more and preferably 1% by mass or more.

Further, in the separator of the present invention, a composition containing inorganic particles, a binder and the amine compound (a) is applied onto a resin microporous film or an electrode (an electrode for a non-aqueous electrolyte battery; the same applies hereinafter). It can be produced by a step of forming an inorganic particle layer on the film or the electrode (hereinafter, referred to as Embodiment 1), and an inorganic particle layer containing inorganic particles and a binder in advance is formed on a resin microporous film or on a resin microporous film. It can also be produced through a step of forming on the electrode and further applying the amine compound (a) on the inorganic particle layer (hereinafter referred to as Embodiment 2).

When the separator is produced by the step of the second embodiment, as the amine compound, in addition to the amine compound (a) represented by the general formula (1), a functional group represented by the following general formula (2) is used. An amine compound (b) having a hydrolyzing group can also be used.

In the general formula (2), n is an integer of any of 2 to 6.

The amine compound (b) such as a coupling agent having a functional group represented by the general formula (2) and a hydrolyzing group is previously contained in a composition containing inorganic particles and a binder for forming an inorganic particle layer. When it is contained, it chemically binds to the surface of the inorganic particles and becomes a factor of lowering the binding property of the binder. However, this problem can be prevented by using the step of the second embodiment.

Specific examples of the amine compound (b) having a functional group represented by the general formula (2) and a hydrolyzing group include coupling agents such as silane coupling agents, zirconeate coupling agents, and titanate coupling agents. Among the various compounds distributed under the name of, those having a functional group represented by the above formula (2) can be mentioned.

Examples of the hydrolyzing group of the compound include an alkoxy group that can be transformed into a functional group that can react with the -OH group existing on the surface of the inorganic particles by causing hydrolysis.

The coupling agent having a hydrolyzing group chemically binds to the inorganic particles when it is dried after being applied to the inorganic particle layer, so that elution into the non-aqueous electrolytic solution is suppressed.

Specific examples of the amine compound (b) having a functional group represented by the general formula (2) and a hydrolyzing group include H ₂ NCH ₂ CH ₂ NHCH ₂ CHCH ₂ X (OCH ₃ ) ₃ and H ₂ NCH. ₂ CH ₂ NHCH ₂ CH ₂ CH ₂ X (OCH ₃ ) ₃ , H ₂ NCH ₂ CH ₂ NHCH ₂ CH ₂ CH ₂ X (OC ₂ H ₅ ) ₃ , H ₂ NCH ₂ CH ₂ NHCH ₂ PhCH ₂ CH ₂ X (OCH ₃ ) ₃ , H ₂ NCH ₂ CH ₂ NH (CH ₂ ) ₁₁ X (OCH ₃ ) ₃ , H ₂ NC ₂ H ₄ NHC ₂ H ₄ OXO [CH (CH ₃ ) CH ₃ ] ₃ , H ₂ NC ₂ H ₄ NHC ₃ H ₆ SiCH ₃ (OCH ₃ ) ₂ , H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si (OCH _{3) 3} , H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si (OC ₂ H ₅ ) ₃ (Note that, in each of the above formulas representing the exemplary coupling agent, X represents Si, Zr or Ti, and Ph represents phenylene).

In the case of the second embodiment, for example, on the surface portion of the inorganic particle layer opposite to the resin porous film or the electrode, an amine compound [amine compound (a) and / or amine compound (b). Unless otherwise specified, the same applies to the amine compound in the second embodiment. ] Is formed in the trap layer (A).

The trap layer (A) may be formed on the surface of the inorganic particle layer (upper surface of the inorganic particle layer), or may be formed by containing the amine compound in a pore portion near the surface of the inorganic particle layer. good.

The trap layer (A) can be formed through a step of applying the amine compound on an inorganic particle layer formed on a resin porous film or an electrode. At this time, if the amine compound does not invade the pores of the inorganic particle layer, the trap layer (A) is formed on the surface of the inorganic particle layer (upper surface of the inorganic particle layer). On the other hand, when the amine compound is applied onto the inorganic particle layer, when the amine compound invades the pores of the inorganic particles, the vicinity of the surface of the inorganic particle layer (the surface layer portion of the inorganic particle layer) becomes a trap layer (A). ). Further, the trap layer (A) may be formed from above the inorganic particle layer to the vicinity of the surface of the inorganic particle layer.

When the amine compound is present at the interface between the inorganic particle layer and the resin porous film or the electrode, the adhesion between them tends to decrease. However, when the trap layer (A) is formed through the step of applying the amine compound on the inorganic particle layer, the amine compound is on the surface side of the inorganic particle layer (opposite side of the interface with the resin film or the electrode). It becomes easy to be unevenly distributed. Therefore, as compared with the method of the first embodiment in which the amine compound is dispersed throughout the inside of the inorganic particle layer, it becomes easier to suppress a decrease in the adhesion between the inorganic particle layer and the resin porous film or the electrode. Therefore, by producing the separator by the method of the second embodiment, it is possible to satisfactorily trap the metal ions that may be generated in the battery, and it becomes easy to obtain a separator having excellent heat resistance.

In the method for producing a separator according to the second embodiment, from the viewpoint of ensuring a good trapping function for metal ions, the amine compound [the amine compound (a) represented by the general formula (1) and the general formula (2)) When the amine compound (b) having a functional group represented by and a hydrolyzing group is used in combination, the total amount thereof. same as below. ^{] May be 0.03 g / m 2} or more per unit area of the inorganic particle layer, and preferably 0.07 g / m ² or more. However, if the amount of the amine compound in the inorganic particle layer is too large, even if the trap layer (A) is formed after the formation of the inorganic particle layer, the binder binding property is hindered and the heat of the separator is increased. Shrinkage tends to increase. Therefore, from the viewpoint of not lowering the heat resistance of the separator, the amount of the amine compound applied to the inorganic particle layer is 0.7 g / m ² or less per unit area of the inorganic particle layer, preferably 0. It is desirable to form the trap layer (A) so that the content is 3 g / m ^{2 or less.}

When the separator is produced by the method of the second embodiment, the adhesion between the inorganic particle layer and the resin porous film or the electrode is less likely to decrease as compared with the method of the first embodiment. The content of the binder in the inorganic particle layer containing the obtained amine compound does not necessarily have to be 2% by mass or more, and it is possible to secure the required adhesion with a content smaller than that.

The inorganic particles used in the inorganic particle layer of the separator are not particularly limited as long as they are electrochemically stable and electrically insulating, but they preferably have heat resistance. The heat resistance of the inorganic particles is more preferably 200 ° C. or higher. When the heat resistant temperature of the inorganic particles is 200 ° C. or higher, it means that no shape change such as deformation is visually confirmed at at least 200 ° C. The heat resistant temperature of the inorganic particles is more preferably 300 ° C. or higher.

For example, the inorganic particles of iron oxide _{(Fe x} O y; FeO, such _{Fe 2 O 3), SiO 2} , Al 2 O 3, TiO 2, BaTiO 3, inorganic oxides such as ZrO _2; aluminum nitride, silicon nitride Inorganic nitrides such as; sparingly soluble ionic crystals such as calcium fluoride, barium fluoride, barium sulfate, calcium carbonate; covalent crystals such as silicon and diamond; clay such as montmorillonite; and the like. Here, the inorganic oxide may be a substance derived from mineral resources such as boehmite, zeolite, apatite, kaolin, mullite, spinel, olivine, mica, or an artificial product thereof. Further, _{the surface of a conductive material exemplified by a metal, a conductive oxide such as SnO 2} , tin-indium oxide (ITO), or a carbonaceous material such as carbon black or graphite is provided with a material having electrical insulation (a material having electrical insulation (). For example, the particles may be coated with the above-mentioned inorganic oxide or the like to provide electrical insulation. The above-mentioned inorganic particles may be used alone or in combination of two or more. Among the above-mentioned inorganic oxides, Al ₂ O ₃ , SiO ₂ and boehmite are particularly preferably used.

The shape of the inorganic particles may be, for example, a shape close to a spherical shape or a plate shape, but from the viewpoint of better preventing short circuits (particularly short circuits due to dendrites), plate-shaped particles are used. It is preferable to have. Typical examples of the plate-shaped particles include plate-shaped Al ₂ O ₃ and plate-shaped boehmite, and these may be used alone or in combination of two or more. Further, from the viewpoint of further enhancing the action of suppressing the heat shrinkage of the entire separator, the inorganic particles are preferably in the form of secondary particles in which primary particles are connected.

As for the form of the plate-like particles, it is desirable that the aspect ratio is 5 or more, more preferably 10 or more, and 100 or less, more preferably 50 or less. Further, the average value of the ratio of the length in the major axis direction to the length in the minor axis direction (length in the major axis direction / length in the minor axis direction) of the flat plate surface of the particles is 3 or less, more preferably 2 or less, which is close to 1. It is desirable that it is a value.

The average value of the ratio of the length in the major axis direction to the length in the minor axis direction of the flat plate surface in the plate-shaped particles can be obtained by, for example, image analysis of an image taken by a scanning electron microscope (SEM). can. Further, the aspect ratio of the plate-shaped particles can also be obtained by image analysis of the image taken by SEM.

Further, it is preferable that the flat plate surface of the plate-shaped particles in the separator is substantially parallel to the surface of the separator, and more specifically, the plate-shaped particles in the inorganic particle layer have the flat plate surface. The average angle with the separator surface is preferably 30 ° or less [most preferably, the average angle is 0 °, that is, the plate-shaped flat plate surface in the inorganic particle layer of the separator is parallel to the surface of the separator. be〕.

If the average particle size of the inorganic particles is too small, the pore size of the separator (inorganic particle layer) may become too small and the permeability of ions such as lithium ions may decrease. Therefore, the average particle size may be 0.01 μm or more. It is preferably 0.1 μm or more, and more preferably 0.1 μm or more. However, if the particle size of the inorganic particles is too large, the separator (inorganic particle layer) may become too thick and the energy density of the battery may decrease. Therefore, the average particle size of the inorganic particles is 15 μm or less. It is preferably 5 μm or less, and more preferably 5 μm or less.

For the average particle size of the inorganic particles referred to in the present specification, for example, a laser scattering particle size distribution meter (for example, "LA-920" manufactured by HORIBA) is used, and in the case of inorganic particles, the inorganic particles are placed in a medium that does not dissolve them. Can be specified as the number average particle diameter measured by dispersing the particles, and unless otherwise specified, the secondary particle-like particles mean the average particle diameter of the secondary particles.

The binder used for the inorganic particle layer includes ethylene-vinyl acetate copolymer (EVA, which has a structural unit derived from vinyl acetate of 20 to 35 mol%) and ethylene-acrylic acid such as ethylene-ethyl acrylate copolymer. Polymer, fluororubber, styrene butadiene rubber (SBR), carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinylpyrrolidone (PVP), crosslinked acrylic resin, polyurethane, Examples thereof include an epoxy resin, and in particular, a heat-resistant binder having a heat-resistant temperature of 150 ° C. or higher is preferably used. As the binder, one of the above-exemplified binders may be used alone, or two or more kinds of binders may be used in combination.

Among the above-exemplified binders, highly flexible binders such as EVA, ethylene-acrylic acid copolymer, fluorinated rubber, and SBR are preferable. Specific examples of such highly flexible binders include Mitsui DuPont Polychemical's "Evaflex Series (EVA)", Nippon Unicar's EVA, and Mitsui DuPont Polychemical's "Evaflex-EEA Series (Ethylene-". Acrylic acid copolymer) ”, EEA of Nippon Unicar Co., Ltd., Daikin Industries Co., Ltd.“ Daiel Latex Series (Fluororubber) ”, JSR Corporation“ TRD-2001 (SBR) ”, Nippon Zeon Co., Ltd.“ BM-400B ( SBR) ”and the like.

In the inorganic particle layer, the inorganic particles are the main constituents thereof, and the amount of the inorganic particles in the inorganic particle layer is preferably 50% by mass or more, preferably 80% by mass or more, based on the total amount of the constituent components of the inorganic particle layer. It is more preferable that the amount is 90% by mass or more.

Further, as described above, since the inorganic particle layer contains a binder for binding the inorganic particles to each other, the amount of the inorganic particles in the inorganic particle layer is 99 out of the total amount of the constituent components of the inorganic particle layer. It is preferably 9% by mass or less, more preferably 98% by mass or less, and particularly preferably 94% by mass or less. When the separator is produced by the method of the first embodiment, it is contained in the composition when the composition containing the inorganic particles, the binder and the amine compound is applied onto the resin microporous film or the electrode. If the amount of the inorganic particles is determined so that the proportion of the binder is 2% by mass or more and the proportion of the amine compound is 0.5 to 7% by mass in the total amount of the solid content (inorganic particles, binder and amine compound). good.

The inorganic particle layer functions as a separator by itself, but it is preferable to form a separator together with a resin microporous film in order to have a shutdown function or the like.

The resin microporous film used for the separator was composed of one or more of polyolefins such as polyethylene (PE) such as low density polyethylene, high density polyethylene and ultrahigh molecular weight polyethylene; polypropylene (PP); It is preferable that it is made of. These polyolefins are thermoplastic resins having a melting temperature of 80 to 180 ° C. measured using a differential scanning calorimeter (DSC) in accordance with the provisions of JIS K7121, and the separator is composed of such polyolefins. By having the porous film, it is possible to secure the so-called shutdown characteristic in which the polyolefin softens when the temperature inside the battery becomes high and the pores of the separator are closed.

The resin porous film is an ion-permeable porous film having a large number of pores formed by a conventionally known solvent extraction method, a dry method, a wet stretching method, or the like (microporous, which is widely used as a battery separator). Membrane) can be used.

When the resin porous film is a porous film made of polyolefin (microporous film), for example, it may be one using only PE or only PP, or a microporous film made of PE. It may be a laminate with a microporous film made of PP (for example, a PP / PE / PP three-layer laminate).

The resin porous film may contain a filler or the like. Examples of such a filler include various inorganic particles exemplified above as those that can be used for the inorganic particle layer.

In the resin porous film, the amount of the main resin in the total product of the constituent components is preferably 50% by volume or more, more preferably 70% by volume or more. The resin porous film may be composed of only resin, and in that case, the amount of resin in the total product of the constituent components in the resin porous film is 100% by volume.

The resin porous membrane film is preferably 5 μm or more, more preferably 10 μm or more, for example, from the viewpoint of improving the strength of the separator. Further, from the viewpoint of reducing the total thickness of the separator and further improving the capacity and output density of the battery, the thickness of the resin porous film is preferably 35 μm or less, more preferably 20 μm or less.

The resin porous film may be used by being superposed on the inorganic particle layer formed on the electrode, or the inorganic particle layer may be formed on one side or both sides and used integrally with the inorganic particle layer. May be good.

The surface of the resin porous film can be modified in order to improve the adhesiveness with the inorganic particle layer. In particular, a porous film made of polyolefin generally does not have high surface adhesiveness, so that surface modification is often effective.

Examples of the surface modification method for the resin porous film include corona discharge treatment, plasma discharge treatment, and ultraviolet irradiation treatment. From the viewpoint of dealing with environmental problems, for example, it is more desirable to use water as the solvent of the composition for forming the inorganic particle layer, and from this, especially when a porous polyolefin film is used, the surface is used. It is very preferable to increase the hydrophilicity of the surface by modification.

The inorganic particle layer is formed by applying a composition containing inorganic particles and a binder (composition for forming an inorganic particle layer) onto a resin porous film or on at least one electrode selected from a positive electrode and a negative electrode. ..

For the composition for forming the inorganic particle layer, a slurry or paste prepared by dispersing inorganic particles and a binder in a solvent such as water or an organic solvent (the binder may be dissolved in the solvent) can be used. can.

In the method for producing a separator according to the first embodiment, the amine compound (a) is also contained in the composition for forming an inorganic particle layer.

For coating the composition for forming an inorganic particle layer on the surface of the resin porous film or the electrode, for example, a known coating device such as a blade coater, a roll coater, a die coater, a spray coater, or a gravure coater can be used. When plate-shaped particles are used as the inorganic particles contained in the inorganic particle layer, the coated composition for forming the inorganic particle layer should be shared from the viewpoint of enhancing the orientation of the plate-shaped particles in the separator. Is preferable. Therefore, when plate-shaped particles are used as the inorganic particles, among the above-mentioned coating devices, a coating device such as a blade coater or a die coater that can apply a share to the composition for forming an inorganic particle layer at the time of coating is used. Is preferable.

The solvent used in the composition for forming the inorganic particle layer may be any solvent as long as it can uniformly disperse inorganic particles and the like, and can uniformly dissolve or disperse the binder. For example, aromatic hydrocarbons such as toluene and tetrahydrofuran. Common organic solvents such as furans such as furan, methyl ethyl ketone, and ketones such as methyl isobutyl ketone are preferably used. Alcohol (ethylene glycol, propylene glycol, etc.) or various propylene oxide-based glycol ethers such as monomethyl acetate may be appropriately added to these solvents for the purpose of controlling the interfacial tension. Further, when the binder is water-soluble or used as an emulsion, water may be used as a solvent as described above, and in this case as well, alcohols (methyl alcohol, ethyl alcohol, isopropyl alcohol, ethylene glycol, etc.) and various types are used. It is also possible to control the interfacial tension by appropriately adding a surfactant.

The content of the solid content (components excluding the solvent) of the composition for forming the inorganic particle layer is preferably 10 to 80% by mass, for example.

After applying the composition for forming an inorganic particle layer to a resin porous film or an electrode, it is usually dried. For drying, a method and conditions that can satisfactorily remove the solvent of the composition for forming the inorganic particle layer and do not deteriorate the inorganic particle layer, the resin porous film, or the electrode may be adopted. For example, about 20 to 100 ° C. A method of drying for about 0.1 to 10 minutes using warm air of the above can be mentioned.

The inorganic particle layer may be formed on only one side of the resin porous film or the electrode, or may be formed on both sides, if necessary.

The thickness of the inorganic particle layer (if the separator has a plurality of inorganic particle layers, the total thickness. The thickness of the inorganic particle layer is the same below) controls the thermal shrinkage of the separator and is derived from foreign substances and positive electrodes mixed in. From the viewpoint of adsorbing the eluted metal ions, preventing internal short circuits and improving the reliability of the battery, the thickness is 2 μm or more, more preferably 3 μm or more. However, if the thickness of the inorganic particle layer is too thick, Li involved in charging / discharging may be adsorbed, or the total thickness of the separator may become large, which may cause deterioration of the load characteristics of the battery. Therefore, the thickness of the inorganic particle layer is preferably 10 μm or less, and more preferably 5 μm or less.

The separator of the present invention can be obtained by forming an inorganic particle layer containing the amine compound (a) on the resin porous film or the electrode as described above by the method for producing the separator according to the first embodiment. can.

On the other hand, the separator of the present invention is an amine compound on the inorganic particle layer of the laminate of the inorganic particle layer obtained as described above and the resin porous film or the electrode by the method for producing the separator of the second embodiment [the above. Manufactured through a step of applying an amine compound (a) represented by the general formula (1) or an amine compound (b) having a functional group and a hydrolyzing group represented by the general formula (2). You can also do it.

When the amine compound is applied onto the inorganic particle layer, in the case of a compound that is liquid at room temperature, the compound can be used as it is for application, but usually, a solution dissolved in a solvent is used for application. Examples of the solvent for dissolving the amine compound include water; organic solvents such as alcohols [ethanol, isopropanol (IPA), etc.] and N-methyl-2-pyrrolidone (NMP).

The concentration of the amine compound in the solution in which the amine compound is dissolved in a solvent is preferably 0.1 to 20% by mass.

After applying the amine compound (or a solution thereof) on the inorganic particle layer, it is usually dried to obtain a separator.

For drying, for example, a method and conditions that do not deteriorate the inorganic particle layer, the resin porous film, or the electrode may be adopted. For example, the drying is performed for about 0.1 to 20 minutes using warm air of about 20 to 100 ° C. The method etc. can be mentioned.

From the viewpoint of ensuring sufficient strength, the thickness of the separator is preferably 0.5 μm or more when the inorganic particle layer is used alone, such as when the inorganic particle layer is formed on the electrode, and is preferably 1 μm. The above is more preferable, and when the inorganic particle layer and the resin porous film are combined to form a separator, it is preferably 10 μm or more, and more preferably 15 μm or more. However, if the separator is too thick, the output characteristics of the battery may deteriorate. Therefore, when the inorganic particle layer is used alone, the thickness of the separator is preferably 6 μm or less, and preferably 4 μm or less. When the inorganic particle layer and the resin porous film are combined to form a separator, the thickness is preferably 40 μm or less, and more preferably 25 μm or less.

The porosity of the separator is preferably 30% or more, and preferably 70% or less when the separator is dry. If the porosity of the separator is too small, the movement of ions in the separator may be hindered, and if this is too large, the strength of the separator may decrease.

The porosity of the separator referred to in the present specification is a value calculated by calculating the sum of each component i using the following formula (3) from the thickness of the separator, the mass per area, and the density of the constituent components. be.

P = 100- (Σai / ρi) x (m / t) (3)

Here, in the above formula (3), ai: the ratio of the component i expressed in% by mass, ρi: the density of the component i (g / cm ³ ), m: the mass per unit area of the separator (g / cm ² ). , T: Thickness (cm) of the separator.

The separator has an air permeability represented by a Garley value specified in JIS P 8117, preferably 50 seconds or more, more preferably 100 seconds or more, and preferably 600 seconds or less. More preferably, it is 300 seconds or less. If the Garley value is too small, lithium dendrite crystals and the like can easily penetrate, and the effect of suppressing internal short circuits may be small. If the Garley value is too large, the ionic conductivity becomes too low and the internal resistance of the battery becomes large. Therefore, there is a risk that the load characteristics will deteriorate.

Further, the separator preferably has a maximum pore diameter measured by the bubble point method specified in JIS K 3832 (hereinafter, simply referred to as "maximum pore diameter") of 0.01 μm or more and 1 μm or less. If the maximum pore diameter of the separator is too small, the pore diameter of the separator is too small, the ion permeability is deteriorated, and the internal resistance of the battery may become too large. On the other hand, if the maximum pore size of the separator is too large, the pore size of the separator becomes too large, and short circuits due to direct contact between the positive electrode and the negative electrode are likely to occur, or the effect of suppressing internal short circuits by lithium dendrite crystals is reduced. There is a risk of

The Garley value and the maximum pore diameter of the separator can be set to the above values by adopting the configurations described in detail so far.

The non-aqueous electrolyte battery of the present invention is composed of a positive electrode, a negative electrode, and a separator of the present invention interposed between the positive electrode and the negative electrode.

The positive electrode is not particularly limited as long as it is a positive electrode used in a conventionally known non-aqueous electrolyte battery, that is, a positive electrode containing an active material capable of occluding and releasing Li ions. For example, as the positive electrode active material, LiM _x Mn _2-x O ₄ (where M is Li, B, Mg, Ca, Sr, Ba, Ti, V, Cr, Fe, Co, Ni, Cu, Al, Spinel-type lithium manganese represented by 0.01 ≦ x ≦ 0.5), which is at least one element selected from the group consisting of Sn, Sb, In, Nb, Mo, W, Y, Ru and Rh. composite _{oxides, Li x Mn (1-y} -x) Ni y M z O (2-k) F l ( although, M is, Co, Mg, Al, B , Ti, V, Cr, Fe, Cu, It is at least one element selected from the group consisting of Zn, Zr, Mo, Sn, Ca, Sr and W, and is 0.8 ≦ x ≦ 1.2, 0 <y <0.5, 0 ≦ z ≦. A layered compound represented by 0.5, k + l <1, −0.1 ≦ k ≦ 0.2, 0 ≦ l ≦ 0.1), LiCo _1-x M _x O ₂ (where M is Al, It is at least one element selected from the group consisting of Mg, Ti, Zr, Fe, Ni, Cu, Zn, Ga, Ge, Nb, Mo, Sn, Sb and Ba, and is 0 ≦ x ≦ 0.5). Lithium-cobalt composite oxide represented by, LiNi _1-x M _x O ₂ (where M is Al, Mg, Ti, Zr, Fe, Co, Cu, Zn, Ga, Ge, Nb, Mo, Sn, At least one element selected from the group consisting of Sb and Ba, a lithium nickel composite oxide represented by 0 ≦ x ≦ 0.5), LiM _1-x N _x O ₂ (where M is. At least one element selected from the group consisting of Fe, Mn and Co, where N is from Al, Mg, Ti, Zr, Ni, Cu, Zn, Ga, Ge, Nb, Mo, Sn, Sb and Ba. It is at least one element selected from the above group, and examples thereof include an olivine type composite oxide represented by 0 ≦ x ≦ 0.5), and only one of these elements may be used. Seeds or more may be used together.

In the non-aqueous electrolyte battery of the present invention, metal ions that elute from the positive electrode and precipitate on the negative electrode to deteriorate the battery characteristics or cause a short circuit are effectively trapped by the action of the amine compound contained in the separator. can do. Therefore, in the non-aqueous electrolyte battery of the present invention, when a lithium manganese composite oxide, a lithium nickel cobalt manganese composite oxide, or the like containing Mn easily eluted in the electrolytic solution as a constituent element is used as the positive electrode active material, the present invention is used. The effect is particularly remarkable.

As the positive electrode, one having a structure in which the positive electrode mixture layer containing the above-mentioned positive electrode active material and a conductive auxiliary agent or a binder is formed on one side or both sides of the current collector can be used.

As the binder of the positive electrode, for example, a fluororesin such as polyvinylidene fluoride (PVDF) is used, and as the conductive auxiliary agent of the positive electrode, for example, a carbon material such as carbon black is used.

Further, as the current collector of the positive electrode, a metal foil such as aluminum, a punching metal, a net, an expanded metal or the like can be used, but usually, an aluminum foil having a thickness of 10 to 30 μm is preferably used.

The lead portion on the positive electrode side is usually provided by leaving an exposed portion of the current collector without forming a positive electrode mixture layer on a part of the current collector at the time of producing the positive electrode and using this as the lead portion. However, the lead portion is not necessarily required to be integrated with the current collector from the beginning, and may be provided by connecting an aluminum foil or the like to the current collector later.

The negative electrode is not particularly limited as long as it is a negative electrode used in a conventionally known non-aqueous electrolyte battery, that is, a negative electrode containing an active material capable of occluding and releasing Li ions. For example, carbons capable of storing and releasing lithium such as graphite, pyrolytic carbons, cokes, glassy carbons, calcined organic polymer compounds, mesocarbon microbeads (MCMB), and carbon fibers as active materials. One or a mixture of two or more of the system materials is used. Further, a simple substance containing elements such as Si, Sn, Ge, Bi, Sb, and In, a compound and an alloy thereof, a lithium-containing nitride, a compound that can be charged and discharged at a low voltage close to that of a lithium metal such as an oxide, or a lithium metal. , Lithium / aluminum alloys, and _{Ti oxides such as those represented by Li 4} Ti ₅ O ₁₂ can also be used as the negative electrode active material. A negative electrode mixture in which a conductive auxiliary agent (carbon material such as carbon black) or a binder such as PVDF is appropriately added to these negative electrode active materials is finished into a molded body (negative electrode mixture layer) using a current collector as a core material. Or the above-mentioned various alloys or lithium metal foils are used alone or laminated on a current collector as a negative electrode active material layer.

When a current collector is used for the negative electrode, copper or nickel foil, punching metal, net, expanded metal, etc. can be used as the current collector, but copper foil is usually used. When the thickness of the entire negative electrode of this negative electrode current collector is reduced in order to obtain a battery having a high energy density, the upper limit of the thickness is preferably 30 μm, and the lower limit is preferably 5 μm. Further, the lead portion on the negative electrode side may be formed in the same manner as the lead portion on the positive electrode side.

The positive electrode and the negative electrode are formed into an electrode body such as a laminated electrode body laminated via a separator or a wound electrode body wound around the same, and these electrode bodies are enclosed together with a non-aqueous electrolyte in the exterior body. Then, a non-aqueous electrolyte battery can be obtained.

As the non-aqueous electrolyte related to the non-aqueous electrolyte battery, a solution in which a lithium salt is dissolved in an organic solvent (non-aqueous electrolyte solution) can be used.

The lithium salt of the non-aqueous electrolyte solution ^{is not particularly limited as long as it dissociates in a solvent to form Li +} ions and does not easily cause side reactions such as decomposition in the voltage range used as a battery. For example, inorganic lithium salts such as _{LiClO 4} , LiPF ₆ , LiBF ₄ , _{LiAsF 6} , LiSbF _{6 ; LiCF 3} SO ₃ , LiCF ₃ CO ₂ , Li ₂ C ₂ F ₄ (SO ₃ ) ₂ , LiN (CF ₃ SO _2). ) ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiC _n F _{2n + 1} SO ₃ (n ≧ 2), LiN (RfOSO ₂ ) ₂ [Here, Rf is a fluoroalkyl group] and other organic lithium salts; can.

The organic solvent used in the non-aqueous electrolyte solution is not particularly limited as long as it dissolves the above-mentioned lithium salt and does not cause side reactions such as decomposition in the voltage range used as a battery. For example, cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate; chain carbonates such as dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate; chain esters such as methyl propionate; cyclic esters such as γ-butyrolactone; Chain ethers such as dimethoxyethane, diethyl ether, 1,3-dioxolane, diglime, triglime, tetraglyme; cyclic ethers such as dioxane, tetrahydrofuran, 2-methyltetrax; nitriles such as acetonitrile, propionitrile, methoxypropionitrile Classes; sulfite esters such as ethylene glycol sulfite; and the like; these can also be used by mixing two or more kinds.

The concentration of this lithium salt in the non-aqueous electrolytic solution is preferably 0.5 to 1.5 mol / l, more preferably 0.9 to 1.25 mol / l.

Further, a gel-like electrolyte (gel-like electrolyte) obtained by adding a known gelling agent to the non-aqueous electrolyte solution may be used as the non-aqueous electrolyte.

Examples of the non-aqueous electrolyte battery include a tubular shape (square tubular shape, cylindrical shape, etc.) using a steel can, an aluminum can, or the like as an outer can. Further, a soft package battery having a laminated film on which metal is vapor-deposited as an exterior body can also be used.

Hereinafter, the present invention will be described in detail based on Examples. However, the following examples do not limit the present invention.

Example 1
<Making a separator>
Plate-shaped boehmite (average particle size 1 μm, aspect ratio 10): 1000 g is dispersed in 1000 g of water, and 120 g of a dispersion liquid of SBR latex (solid content ratio 40% by mass) is added as a binder to uniformly disperse the inorganic particles. A layer-forming composition (slurry) was prepared.

The thickness after drying using a die coater on one side of a microporous polyolefin film (thickness 20 μm, porosity 40%) formed by laminating the above slurry in the order of PP layer, PE layer, and PP layer. Was applied to a thickness of 5 μm and dried to obtain a laminate of an inorganic particle layer and a resin porous film having a total thickness of 25 μm.

Diethylenetriamine [amine compound (a)] was dissolved in water to prepare a solution having a diethylenetriamine concentration of 10% by mass. This solution is applied onto the inorganic particle layer of the laminate of the inorganic particle layer and the resin porous film obtained as described above using a spray coater, dried, and the trap layer (A) is formed. A separator having was obtained. The coating amount of diethylenetriamine was 0.13 g / m ² per unit area of the inorganic particle layer, and the content of diethylenetriamine in the formed trap layer (A) was the inorganic particles and binder of the entire inorganic particle layer and the above. It was 2% by mass in the total amount with the amine compound.

<Manufacturing of negative electrode>
A paste containing a negative electrode mixture was prepared by mixing 95 parts by mass of graphite as a negative electrode active material and 5 parts by mass of PVDF as a binder so as to be uniform using NMP as a solvent. This negative electrode mixture-containing paste is intermittently applied to both sides of a 10 μm-thick current collector made of copper foil so that the coating length is 320 mm on the front surface and 260 mm on the back surface. The thickness of the negative electrode mixture layer was adjusted to 142 μm, and the negative electrode mixture layer was cut to a width of 45 mm to prepare a negative electrode having a length of 330 mm and a width of 45 mm. Further, a tab was welded to the exposed portion of the copper foil of the negative electrode to form a lead portion.

<Preparation of positive electrode>
_{LiMn 1.5} Ni _0.5 O ₄ : 85 parts by mass, which is a positive electrode active material, acetylene black: 10 parts by mass, which is a conductive additive, and PVDF: 5 parts by mass, which is a binder, are made uniform using NMP as a solvent. To prepare a positive electrode mixture-containing paste. This paste is intermittently applied to both sides of an aluminum foil having a thickness of 15 μm as a current collector so that the coating length is 320 mm on the front surface and 260 mm on the back surface, and after drying, a calendar treatment is performed to bring the total thickness to 150 μm. The thickness of the positive electrode mixture layer was adjusted so as to be so that the positive electrode was cut so as to have a width of 43 mm to prepare a positive electrode having a length of 330 mm and a width of 43 mm. Further, a tab was welded to the exposed portion of the aluminum foil of the positive electrode to form a lead portion.

<Battery assembly>
The negative electrode, the positive electrode, and the separator were superposed so that the positive electrode was arranged on the inorganic particle layer side of the separator, and wound in a spiral shape to prepare a wound electrode body. This wound electrode body is crushed to make it flat, loaded in a battery container, and 1.2 mol / mol / mol _{of LiPF 6} is added to a solvent in which a non-aqueous electrolyte solution (ethylene carbonate and ethyl methyl carbonate are mixed at a volume ratio of 1: 2). A solution dissolved at a concentration of l) was injected into the battery container and then sealed to obtain a non-aqueous electrolyte battery.

Example 2
A separator was prepared in the same manner as in Example 1 except that triethylenetetramine was used instead of diethylenetriamine, and a non-aqueous electrolyte battery was prepared in the same manner as in Example 1 except that this separator was used.

Example 3
A separator was prepared in the same manner as in Example 1 except that 3,3-diaminodipropylamine was used instead of diethylenetriamine, and a non-aqueous electrolyte battery was prepared in the same manner as in Example 1 except that this separator was used. ..

Example 4
A separator was prepared in the same manner as in Example 1 except that tris (2-aminoethyl) amine was used instead of diethylenetriamine, and a non-aqueous electrolyte battery was prepared in the same manner as in Example 1 except that this separator was used. ..

Example 5
Plate-shaped boehmite (average particle size 1 μm, aspect ratio 10): 1000 g is dispersed in 1000 g of water, and 120 g of SBR latex dispersion (solid content ratio 40% by mass) and diethylenetriamine: 50 g are added as binders to make it uniform. A composition (slurry) for forming an inorganic particle layer was prepared. The slurry was applied to one side of the same polyolefin microporous film (thickness 20 μm, porosity 40%) as in Example 1 using a die coater, and dried to form an inorganic particle layer having a thickness of 5 μm. A separator having a total thickness of 25 μm and made of a laminate of an inorganic particle layer and a resin porous film was obtained. The binder content in the inorganic particle layer was 4.4% by mass, and the amine compound content was 4.6% by mass.

Then, a non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that this separator was used.

Comparative Example 1
A non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that the laminate of the inorganic particle layer and the resin porous film was used as it was as a separator without applying diethylenetriamine.

Comparative Example 2
A separator was prepared in the same manner as in Example 1 except that the coating amount of diethylenetriamine was 0.98 g / m ² per unit area of the inorganic particle layer, and the separator was not used in the same manner as in Example 1 except that this separator was used. A water electrolyte battery was prepared.

The content of diethylenetriamine in the trap layer (A) of the prepared separator was 13.1% by mass based on the total amount of the inorganic particles and binder of the entire inorganic particle layer and the amine compound.

Comparative Example 3
When preparing the composition (slurry) for forming the inorganic particle layer, a separator was prepared in the same manner as in Example 5 except that the amount of the dispersion liquid of SBR latex added was 50 g, and Example 1 except that this separator was used. A non-aqueous electrolyte battery was produced in the same manner as in the above.

The binder content was 1.9% by mass and the amine compound content was 4.7% by mass in the inorganic particle layer of the prepared separator.

Comparative Example 4
When preparing the composition (slurry) for forming an inorganic particle layer, a separator was prepared in the same manner as in Example 5 except that the amount of diethylenetriamine added was 80 g, and the same as in Example 1 except that this separator was used. A non-aqueous electrolyte battery was prepared.

The binder content was 4.3% by mass and the amine compound content was 7.1% by mass in the inorganic particle layer of the prepared separator.

The following evaluations were performed on the separators and non-aqueous electrolyte batteries produced in Examples and Comparative Examples.

<Measurement of metal ion adsorption amount of separator>
DEC (diethyl carbonate) and EC (ethylene carbonate) were mixed in a volume ratio of 1: 1 to prepare a mixed solvent. CoCl ₂ · xH ₂ O was dissolved in the mixed solvent so as to have a concentration of 0.003 mol / L to prepare an experimental Co solution. The prepared Co solution was used as a standard solution, 5 mL of this Co solution was placed in a glass bottle, a 100 cm ² separator was placed therein, and the mixture was allowed to stand for 24 hours or more, and then the supernatant was collected and used as a sample solution.

Murexide (hereinafter referred to as "MX") manufactured by Dojin Chemical Research Institute was used as a metal indicator. MX is a dark reddish purple powder that produces a stable chelate compound with Ca, Ni, Co, Cu, etc. and turns yellow. In addition, it can be used as a metal indicator because it can be restored to its original color by a chelating agent.

As the chelating agent, an organic solvent-soluble chelating agent "Kirest MZ-8" (trade name) manufactured by Kirest Co., Ltd. was used. However, since Kirest MZ-8 alone is insoluble in DEC and EC, Kirest MZ-8 was dissolved in ethanol to a concentration of 10% by mass to prepare a DEC / EC mixed solvent-soluble chelating agent.

The amount of metal ion adsorbed per unit mass of the inorganic filler was calculated from the amount of the dropped chelating agent and the mass of the inorganic particles applied to the separator.

<Measurement of heat shrinkage of separator>
The separators prepared in Examples and Comparative Examples were cut into rectangles having a length of 5 cm and a width of 10 cm, and a cross line of 3 cm in the vertical direction and 3 cm in the horizontal direction was drawn with black ink to prepare a measurement sample. When cutting the separator into a rectangle, the vertical direction of the separator was set to be the mechanical direction MD: Machine Direction of the microporous membrane of the separator, and the intersection of the crosshairs was set to be the center of the separator piece. .. Each of the above-mentioned measurement samples is hung in a constant temperature bath set at 150 ° C., and after 1 hour, the length of the straight line in the vertical and horizontal directions of each measurement sample is measured, and the length of the straight line before being hung in the constant temperature bath is measured. The amount of change from the above was obtained, and the ratio of these changes to the length of the straight line before hanging in the constant temperature bath was expressed as a percentage and used as the heat shrinkage in the vertical and horizontal directions. Then, the larger value of the heat shrinkage in the vertical direction and the heat shrinkage in the horizontal direction of each measurement sample was taken as the heat shrinkage of each separator.

<Measurement of water content of separator>
The separator was cut into A4 size and left to stand in a dry room for 12 hours or more to prepare a sample for moisture measurement. Using an automatic heating vaporization moisture measurement system: AQS-22010A (manufactured by Hiranuma Sangyo Co., Ltd.), the sample was heated to 150 ° C. in a nitrogen stream of 150 ml / min, and the amount of adsorbed moisture was measured.

<Battery characterization>
For each of the batteries of the examples and the comparative examples, the operation of charging to 4.2 V at a current value of 0.5 C with respect to the design capacity and discharging to 3 V at a current value of 0.5 C is repeated twice for two cycles. The discharge capacity of the eyes was measured and used as the initial capacity of each battery.

Further, each battery after the initial capacity measurement is charged under the same conditions as described above, then stored at a high temperature of 80 ° C. for 24 hours, allowed to cool to room temperature, and then reaches 3 V at a current value of 0.5 C. The discharge capacity was determined by discharging to, the capacity retention rate was determined by comparison with the charge capacity before high temperature storage, and the state of self-discharge considered to be caused by eluted ions was evaluated.
Capacity retention rate (%) = (Discharge capacity after high temperature storage) / (Charge capacity before high temperature storage) x 100

For each of the evaluated batteries, the charge / discharge cycle was further repeated twice under the same conditions as described above, and the discharge capacity of the second cycle was determined. From the discharge capacity of the second cycle and the initial capacity, the capacity recovery rate (%) was calculated according to the following formula, and the degree of deterioration of each battery was evaluated by this.
Capacity recovery rate (%) = (Discharge capacity in the second cycle after high temperature storage) / (Initial capacity) x 100

A battery with little deterioration recovers its capacity after several charging and discharging, and the capacity recovery rate increases. Therefore, the degree of deterioration of the battery can be evaluated from that value.

Table 1 shows the configurations of the separators of Examples and Comparative Examples, Table 2 shows the evaluation results, and Table 3 shows the evaluation results of the batteries of Examples and Comparative Examples. The values in parentheses in Table 1 are the average values of the content ratios of the respective components in the total amount of the inorganic particles, the binder and the amine compound (a) contained in the entire inorganic particle layer and the trap layer (A). Show that you did.

As is clear from the results shown in Tables 1 to 3, the separators of Examples 1 to 5 produced by the method for producing the separator of the first or second embodiment are eluted by the action of the specific amine compound (a). The metal can be sufficiently adsorbed, the action of the amine compound to reduce the binder binding property of the inorganic particle layer is suppressed, the heat shrinkage is small, and the amount of adsorbed water content due to the amine compound (a) is also increased. It was suppressed. Therefore, the non-aqueous electrolyte batteries using the separators of Examples 1 to 5 have low self-discharge and little deterioration of the battery due to high temperature storage.

On the other hand, in the non-aqueous electrolyte battery of Comparative Example 1 in which the inorganic particle layer did not contain the amine compound (a), the function of adsorbing the eluted metal to the separator except that the inorganic particles (bemite) slightly adsorbed the eluted metal. Because it is not equipped with, there is a lot of self-discharge, and the deterioration of the battery due to high temperature storage is large.

Further, in the method for producing the separator of the second embodiment, the amount of the amine compound (a) applied on the inorganic particle layer is too large, and in the method for producing the separator of the comparative example 2 and the separator of the first embodiment, the inorganic particle layer is formed. The separator of Comparative Example 3 in which the proportion of the binder is too small and the separator of Comparative Example 4 in which the proportion of the amine compound (a) is too large in the total amount of the inorganic particles, the binder and the amine compound (a) contained in the composition. In each case, the binding property of the inorganic particle layer was lowered, so that the heat shrinkage rate was increased and the heat resistance was lowered.

Further, not only the separators of Comparative Example 2 and Comparative Example 4 in which the content of the amine compound (a) in the inorganic particle layer is higher than that of the separator of the example, but also the binder and the amine compound (a) due to the decrease in the binder content. As for the separator of Comparative Example 3 in which the interaction between the two was reduced, the amount of adsorbed water was significantly increased by the amine compound, so that the non-aqueous electrolyte battery using these separators had a lot of self-discharge and the battery deteriorated due to high temperature storage. Has grown.

Example 6
<Making a separator>
A separator was prepared in the same manner as in Example 4 except that the amount of tris (2-aminoethyl) amine applied was 0.33 g / m ^{2 per unit area of the inorganic particle layer.} The content of tris (2-aminoethyl) amine in the trap layer (A) formed in the inorganic particle layer is 4.8% by mass based on the total amount of the inorganic particles and binder of the entire inorganic particle layer and the amine compound. Met.

<Preparation of positive electrode>
_{LiNi 0.5} Co _0.2 Mn _0.3 O ₂ : 92 parts by mass, which is a positive electrode active material, acetylene black: 5 parts by mass, which is a conductive additive, and PVDF: 3 parts by mass, which is a binder, are mixed. Further, an appropriate amount of NMP was added, and mixing and dispersion were carried out using a planetary mixer to prepare a slurry for forming a positive electrode mixture layer.

Next, the slurry for forming the positive electrode mixture layer is applied to both sides of an aluminum foil having a thickness of 15 μm as a current collector so that the ^{coating amount after drying is 15 mg / cm 2, and the coating length is 280 mm on the front surface and 210 mm on the back surface.} After intermittent coating and drying, a calendar treatment and a heat treatment at 120 ° C. for 8 hours were performed to adjust the thickness of the positive electrode mixture layer so that the total thickness was 110 μm. This was cut to a width of 43 mm to prepare a positive electrode. Further, an aluminum lead piece for extracting an electric current was welded to the exposed portion of the aluminum foil to obtain a positive electrode with a lead.

<Manufacturing of negative electrode>
Add an appropriate amount of ion-exchanged water to the negative electrode mixture consisting of graphite (average particle size: 10 μm): 97 parts by mass, which is the negative electrode active material, and CMC: 1.5 parts by mass and SBR: 1.5 parts by mass, which are binders. It was added and mixed well to prepare a paste for forming a negative electrode mixture layer.

Next, the paste for forming the negative electrode mixture layer is applied ^{to both sides of a 10 μm-thick current collector made of copper foil so that the coating amount is 9 mg / m 2} after drying, and the coating length is 290 mm on the front surface and 230 mm on the back surface. After intermittent coating and drying, calendar treatment and heat treatment at 120 ° C. for 8 hours were performed to adjust the thickness of the negative electrode mixture layer so that the total thickness was 126 μm. This was cut to a width of 45 mm to prepare a negative electrode. Further, a nickel lead piece for extracting an electric current was welded to the exposed portion of the copper foil to obtain a negative electrode with a lead.

<Battery assembly>
The negative electrode, the positive electrode, and the separator were superposed so that the positive electrode was arranged on the inorganic particle layer side of the separator, and wound in a spiral shape to prepare a wound electrode body. This wound electrode body is crushed to make it flat, loaded in a battery container, and 1.2 mol / mol / mol _{of LiPF 6} is added to a solvent in which a non-aqueous electrolyte solution (ethylene carbonate and ethyl methyl carbonate are mixed at a volume ratio of 1: 2). A solution prepared by dissolving at a concentration of 1 l and adding 3% by mass of vinylene carbonate) was injected into the battery container, and then sealed to obtain a non-aqueous electrolyte battery.

Comparative Example 5
A non-aqueous electrolyte battery was produced in the same manner as in Example 6 except that the same separator as in Comparative Example 1 was used.

<Evaluation of charge / discharge cycle characteristics>
The non-aqueous electrolyte batteries of Example 6 and Comparative Example 5 were subjected to a charge / discharge cycle test under the following conditions under a temperature environment of 45 ° C.

Charging was constant current charging up to 4.2V with a current value of 1C and constant voltage charging at 4.2V, and the total charging time from the start of constant current charging to the end of constant voltage charging was 3 hours. The discharge was a constant current discharge up to 2.5 V with a current value of 1C.

The charge / discharge cycle under the above conditions was repeated, and the charge / discharge cycle characteristics were evaluated by the number of cycles until the discharge capacity decreased to 70% of the initial value. The results obtained are shown in Table 4.

The non-aqueous electrolyte battery of Example 6 was able to improve the charge / discharge cycle characteristics as compared with the non-aqueous electrolyte battery of Comparative Example 5 because the separator trapped the metal eluted from the positive electrode.

Example 7
<Making a separator>
Plate-shaped boehmite (average particle size 1 μm, aspect ratio 10): 1000 parts by mass is dispersed in 1000 parts by mass of water, and 120 parts by mass of SBR latex (solid content ratio 40% by mass) is added as a binder to uniformly disperse. Prepared a slurry for forming an inorganic particle layer.

The thickness after drying using a die coater on one side of a microporous polyolefin film (thickness 20 μm, porosity 40%) formed by laminating the above slurry in the order of PE layer, PP layer, and PE layer. Was applied to a thickness of 5 μm and dried to obtain a laminate of an inorganic particle layer and a resin porous film having a total thickness of 25 μm.

3- (2-Aminoethylamino) propyltrimethoxysilane [amine compound (b)], which is a silane coupling agent having a functional group represented by the formula (2) and a hydrolyzing group: 2 parts by mass. It was dissolved in 98 parts by mass of water (solvent) to prepare a solution having a concentration of the silane coupling agent of 2% by mass. Using a spray coater on the inorganic particle layer of the laminate of the inorganic particle layer and the resin porous film obtained as described above, plate-like boehmite in the inorganic particle layer: 3-based on 100 parts by mass. (2-Aminoethylamino) Propyltrimethoxysilane: The solution was applied in an amount of 2 parts by mass and dried to obtain a separator.

The amount of the silane coupling agent applied was 0.13 g / m ² per unit area of the inorganic particle layer.

A non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that the above separator was used.

Example 8
A silane coupling agent having a functional group represented by the formula (2) and a hydrolyzing group (3-trimethoxysilylpropyl) diethylenetriamine [amine compound (b)]: 4 parts by mass, 96 parts by mass. A solution having a concentration of 4% by mass of the silane coupling agent was prepared by dissolving it in water, and (3-trimethoxysilylpropyl) diethylenetriamine: 4 parts by mass with respect to 100 parts by mass of plate-shaped boehmite in the inorganic particle layer. A separator was prepared in the same manner as in Example 7 except that the solution was applied in such an amount, and a non-aqueous electrolyte battery was prepared in the same manner as in Example 7 except that this separator was used.

The amount of the silane coupling agent applied was 0.33 g / m ² per unit area of the inorganic particle layer.

Comparative Example 6
20 parts by mass of (3-trimethoxysilylpropyl) diethylenetriamine was placed in 80 parts by mass of water and stirred to uniformly dissolve the solution to prepare a silane coupling agent solution. The same plate-shaped boehmite as used in Example 7: 100 parts by mass was dispersed in water: 900 parts by mass, and the slurry was prepared. The above-mentioned silane coupling agent solution was added at a certain ratio, and the treatment was carried out for 60 minutes while stirring with a three-one motor. The treated plate-shaped boehmite was filtered off and dried to obtain a plate-shaped boehmite on which the reaction product of (3-trimethoxysilylpropyl) diethylenetriamine was applied to the surface. Then, from the laminate of the inorganic particle layer and the resin microporous film in the same manner as in Example 7 except that the plate-shaped boehmite having the reaction product of (3-trimethoxysilylpropyl) diethylenetriamine applied to the surface was used. A non-aqueous electrolyte battery was produced in the same manner as in Example 7 except that this separator was used.

Comparative Example 7
A non-aqueous electrolyte battery was produced in the same manner as in Example 1 except that the solution of the silane coupling agent was not applied to the laminate of the inorganic particle layer and the resin porous film and used as it was as a separator.

For the separators produced in Examples 7 to 8 and Comparative Examples 6 to 7, the metal ion adsorption amount and the heat shrinkage rate of the separator were measured by the same method as the separator of Example 1, and compared with Examples 7 to 8. The non-aqueous electrolyte batteries produced in Examples 6 to 7 have the same characteristics (initial capacity, capacity retention rate after high temperature storage, and capacity recovery rate after high temperature storage) in the same manner as the non-aqueous electrolyte battery of Example 1. Evaluation was performed.

Table 5 shows the results of each of the above evaluations of the separator, and Table 6 shows the results of each of the above evaluations of the non-aqueous electrolyte battery.

As shown in Table 5, in the separator of the example, the shape retention of the inorganic particle layer was improved as compared with Comparative Example 6, so that the heat shrinkage rate could be lowered, the heat resistance could be improved, and the adsorption of metal ions could be improved. The amount could be equal to or higher than that of Comparative Example 6.

As shown in Table 6, the separator of the example was provided with an inorganic particle layer having excellent adsorption of metal ions, so that deterioration of the battery could be suppressed as compared with Comparative Example 7.

The present invention can be implemented in forms other than the above, as long as the gist of the present invention is not deviated. The embodiments disclosed in the present application are examples, and the present invention is not limited to these embodiments. The scope of the present invention shall be construed in preference to the description of the appended claims over the description of the specification above, and all modifications within the scope of the claims shall be within the scope of the claims. included.

The non-aqueous electrolyte battery of the present invention can be applied to the same applications as various uses in which conventionally known non-aqueous electrolyte batteries are used.

Claims (7)

1. A separator for a non-aqueous electrolyte battery having an inorganic particle layer containing inorganic particles and a binder.
   The inorganic particle layer contains an amine compound (a) represented by the following general formula (1), the binder content in the inorganic particle layer is 2% by mass or more, and the amine compound (a). A separator for a non-aqueous electrolyte battery, characterized in that the content of the particles is 0.5 to 7% by mass.
   

   

   [However, R ¹ : -H or -C _x H _2x NH ₂ (x is an integer of 2 to 6), R ² : -C _y H _2y- (y is any of 2 to 6). Integer), where m is an integer of 1 to 6, and when m is 2 or more, R ¹ may be different from each other.]
2. The separator for a non-aqueous electrolyte battery according to claim 1, wherein x and y are 2 or 3 in the general formula (1).
3. In Formula (1), R ^1: a separator for a nonaqueous electrolyte battery according to claim 1 or 2 is -H.
4. A composition containing inorganic particles, a binder, and an amine compound (a) represented by the following general formula (1) is applied onto a resin microporous film or an electrode, and an inorganic particle layer is formed on the film or the electrode. It has a step of forming, the ratio of the binder is 2% by mass or more, and the ratio of the amine compound (a) is 0 in the total amount of the inorganic particles, the binder and the amine compound (a) contained in the composition. .. A method for producing a separator for a non-aqueous electrolyte battery, which comprises 5 to 7% by mass.
   

   

   [However, R ¹ : -H or -C _x H _2x NH ₂ (x is an integer of 2 to 6), R ² : -C _y H _2y- (y is any of 2 to 6). Integer), where m is an integer of 1 to 6, and when m is 2 or more, R ¹ may be different from each other.]
5. A step of applying a composition containing inorganic particles and a binder onto a resin microporous film or an electrode to form an inorganic particle layer on the film or the electrode.
   It has a step of applying an amine compound on the inorganic particle layer, and has a step of applying the amine compound.
   As the amine compound, an amine compound (a) represented by the following general formula (1) or an amine compound (b) having a functional group and a hydrolyzing group represented by the following general formula (2) is used.
   A method for producing a separator for a non-aqueous electrolyte battery, wherein the coating amount of the amine compound is 0.03 to 0.7 g / m ^{2 per unit area of the inorganic particle layer.}
   

   

   [However, R ¹ : -H or -C _x H _2x NH ₂ (x is an integer of 2 to 6), R ² : -C _y H _2y- (y is any of 2 to 6). Integer), where m is an integer of 1 to 6, and when m is 2 or more, R ¹ may be different from each other.]
   

   

   [However, n is an integer of 2 to 6]
6. A non-aqueous electrolyte battery having a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode.
   A non-aqueous electrolyte battery comprising the separator for a non-aqueous electrolyte battery according to any one of claims 1 to 3 as the separator.
7. A method for manufacturing a non-aqueous electrolyte battery having a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode.
   A method for producing a non-aqueous electrolyte battery, which comprises using a separator for a non-aqueous electrolyte battery produced by the production method according to claim 4 or 5 as the separator.