JP5494116B2 - Nonaqueous electrolyte composition and nonaqueous electrolyte battery - Google Patents

Description

  The present invention relates to a non-aqueous electrolyte, a non-aqueous electrolyte battery, and a method for manufacturing a non-aqueous electrolyte battery. More specifically, the present invention relates to a non-aqueous electrolyte composition and a non-aqueous electrolyte battery that are disposed in contact with at least one of a positive electrode and a negative electrode and include a non-aqueous solvent, an electrolyte salt, a matrix polymer, and ceramic powder.

  In recent years, many portable electronic devices have appeared, and their size and weight have been reduced. Even in batteries used as power sources for portable electronic devices, it is necessary to reduce the size of the battery itself and to efficiently use the storage space in the portable electronic device in order to reduce the size and weight of the portable electronic device. It has been demanded. As a battery that satisfies such a requirement, it is known that a lithium ion secondary battery having a large energy density is most suitable.

  As such a lithium ion secondary battery, for example, a battery using a laminate film as an exterior member has been put into practical use because it is lightweight and has high energy density, and can be manufactured in a very thin shape. . In a battery using a laminate film as an exterior member, for the purpose of liquid leakage resistance and the like, an electrolyte solution and a matrix polymer that holds the electrolyte solution are applied as an electrolyte, which is known as a polymer battery. Yes.

  Such a polymer battery has greatly improved the degree of freedom of shape by using an aluminum laminate film for the exterior member, but on the other hand, the strength may not be sufficient, and when a strong force is applied due to misuse. Is prone to deformation. In this case, there is no problem as long as it is covered with a strong outer packaging, but with the recent demand for higher capacity, the outer packaging has become simpler, and if the deformation is large, a short circuit inside the battery will occur. It tends to occur and may not function as a battery.

  Conventionally, a battery in which ceramics are applied to the electrode surface as described in Patent Document 1 has been proposed for such a problem.

JP-A-10-214640

  However, in the battery described in Patent Document 1, although the strength (load) until a short circuit occurs can be increased and the safety can be improved, the impregnation property of the electrolyte into the electrode is likely to be reduced. As a result, battery characteristics may be degraded.

  The present invention has been made in view of such problems of the prior art. The object is to obtain high safety without significantly degrading the battery characteristics.

In order to solve the above problems, a non-aqueous electrolyte composition of a first invention includes a non-aqueous electrolyte for a positive electrode containing an electrolyte salt, a non-aqueous solvent, and a matrix polymer,
A negative electrode non-aqueous electrolyte containing an electrolyte salt, a non-aqueous solvent, and a matrix polymer,
The thermal conductivity of the ceramic powder contained in the non-aqueous electrolyte for negative electrode is greater than the thermal conductivity of the ceramic powder contained in the non-aqueous electrolyte for positive electrode, or the content of ceramic powder in the non-aqueous electrolyte for negative electrode Is more than the content of the ceramic powder in the non-aqueous electrolyte for a positive electrode .

The nonaqueous electrolyte battery of the second invention includes a positive electrode, a negative electrode,
A separator disposed between the positive electrode and the negative electrode;
An electrolyte salt, a non-aqueous solvent, and a matrix polymer, the positive electrode non-aqueous electrolyte formed on the surface of the positive electrode, an electrolyte salt, a non-aqueous solvent, and a matrix polymer, Consisting of a non-aqueous electrolyte for negative electrode formed on the surface,
A non-aqueous electrolyte in which the thermal conductivity of the non-aqueous electrolyte for negative electrode is larger than the thermal conductivity of the non-aqueous electrolyte for positive electrode,
The thermal conductivity of the ceramic powder contained in the non-aqueous electrolyte for negative electrode is greater than the thermal conductivity of the ceramic powder contained in the non-aqueous electrolyte for positive electrode, or the content of ceramic powder in the non-aqueous electrolyte for negative electrode Is more than the content of the ceramic powder in the non-aqueous electrolyte for a positive electrode .

  In the first and second inventions, at least the nonaqueous electrolyte for negative electrode contains ceramic powder, and the ceramic powder is present in both the nonaqueous electrolyte for positive electrode and the nonaqueous electrolyte for negative electrode. When it is contained, the thermal conductivity of the ceramic powder contained in the negative electrode nonaqueous electrolyte is greater than the thermal conductivity of the ceramic powder contained in the positive electrode nonaqueous electrolyte, or the negative electrode nonaqueous electrolyte The content of the ceramic powder in the electrolyte is preferably larger than the content of the ceramic powder in the non-aqueous electrolyte for positive electrode.

Ceramic powders include aluminum oxide (Al ₂ O ₃ ), zirconium oxide (ZrO), titanium oxide (TiO ₂ ), silicon oxide (SiO ₂ ), magnesium oxide (MgO ₂ ), silicon carbide (SiC), boron nitride ( It is preferable to use at least one selected from the group consisting of BN) and aluminum nitride (AlN).

  In this invention, since the highly conductive ceramic powder is contained in the electrolyte layer facing the negative electrode, heat can be actively diffused in the negative electrode.

  According to the present invention, safety can be improved without degrading battery characteristics such as cycle characteristics even with a battery covered with an exterior member having a simple structure.

It is one Embodiment of the nonaqueous electrolyte battery of this invention, Comprising: It is a disassembled perspective view which shows an example of a laminate type secondary battery. It is sectional drawing along the II-II line of the battery element shown in FIG. It is a schematic diagram which shows the state of the battery element and nonaqueous electrolyte of the nonaqueous electrolyte battery shown in FIG.

Hereinafter, modes for carrying out the invention (hereinafter referred to as “embodiments”) will be described. The description will be given in the following order.
1. First embodiment (example of non-aqueous electrolyte)
2. Second Embodiment (First Example of Nonaqueous Electrolyte Battery)

1. 1st Embodiment In 1st Embodiment, the nonaqueous electrolyte of this invention is demonstrated in detail.

(1-1) Configuration of Nonaqueous Electrolyte The nonaqueous electrolyte composition of the present invention contains an electrolyte salt, a nonaqueous solvent, a matrix polymer, and a predetermined ceramic powder, and is a nonaqueous electrolyte battery. It is suitably used as a non-aqueous electrolyte used in the above. The positive electrode side electrolyte and the negative electrode side electrolyte are formed as gel electrolyte layers by, for example, coating on the surfaces of the positive electrode and the negative electrode, respectively, and then drying and volatilizing the solvent.

  The present invention is characterized in that the positive electrode side electrolyte provided on the positive electrode active material layer and the negative electrode side electrolyte provided on the negative electrode active material layer have higher thermal conductivity in the negative electrode side electrolyte than the positive electrode side electrolyte. . In general, the negative electrode may cause thermal runaway at a lower temperature than the positive electrode. Further, when the positive electrode and the negative electrode are short-circuited, more Joule heat is generated in the negative electrode. For this reason, the safety | security of a nonaqueous electrolyte battery can be improved by suppressing the heat_generation | fever in a negative electrode.

In order to obtain such a positive electrode side electrolyte and a negative electrode side electrolyte, the nonaqueous electrolyte of the present invention is configured as follows.
(I) A ceramic powder having a higher thermal conductivity on average than the ceramic powder mixed with the positive electrode side electrolyte is mixed with the negative electrode side electrolyte. (Ii) The mixing amount of the ceramic powder into the negative electrode side electrolyte is adjusted in the positive electrode side electrolyte. (Iii) Mix ceramic powder only in the negative electrode side electrolyte.

About (i) In this invention, the heat_generation | fever in a negative electrode surface can be diffused more by mixing ceramic powder with higher thermal conductivity than the ceramic powder mixed with the positive electrode side electrolyte with the negative electrode side electrolyte. In the positive electrode side electrolyte and the negative electrode side electrolyte, two or more kinds of ceramic powders may be mixed and used. When two or more kinds of ceramic powders are mixed and used in at least one of the positive electrode side electrolyte and the negative electrode side electrolyte, the thermal conductivity of the ceramic powder added to the negative electrode side electrolyte as a whole or on average increases. To.

  In addition, in this invention, it is preferable that the thermal conductivity of the ceramic powder contained in the negative electrode side electrolyte is 2 times or more of the thermal conductivity of the ceramic powder contained in the positive electrode side electrolyte.

About (ii) In the positive electrode side electrolyte and the negative electrode side electrolyte, the mixing amount of the ceramic powder is the same in the positive electrode side electrolyte and the negative electrode side electrolyte, or the mixing amount of the ceramic powder in the negative electrode side electrolyte is increased. In particular, when ceramic powders having the same thermal conductivity are used in the positive electrode side electrolyte and the negative electrode side electrolyte, the overall thermal conductivity can be increased by increasing the amount of ceramic powder mixed in the negative electrode side electrolyte. Can be improved.

About (iii) From the same viewpoint as (ii), the thermal conductivity of the negative electrode side electrolyte can be improved more than that of the positive electrode side electrolyte by mixing ceramic powder only with the negative electrode side electrolyte.

  Hereinafter, the ceramic powder of the present invention will be described.

[Ceramic powder]
In the present invention, various materials can be used as the ceramic powder. In particular, aluminum oxide (Al ₂ O ₃ ), zirconium oxide (ZrO), titanium oxide (TiO ₂ ), silicon oxide (SiO ₂ ), magnesium oxide ( Representative examples include MgO ₂ ), silicon carbide (SiC), boron nitride (BN), and aluminum nitride (AlN). These ceramic powders can be used alone or in combination of two or more.

Among these ceramic powders, aluminum oxide (Al ₂ O ₃ ), zirconium oxide (ZrO), titanium oxide (TiO ₂ ), silicon oxide (SiO ₂ ), and magnesium oxide (MgO ₂ ) have a thermal conductivity of about 50 W / Ceramic material with m · K or less.

On the other hand, silicon carbide (SiC), aluminum nitride (AlN) and boron nitride (BN) are ceramic materials having a thermal conductivity of about 50 W / m · K or more, and aluminum nitride (AlN) has a particularly high thermal conductivity. doing. Silicon carbide (SiC), aluminum nitride (AlN) and boron nitride (BN) are aluminum oxide (Al ₂ O ₃ ), zirconium oxide (ZrO), titanium oxide (TiO ₂ ), silicon oxide (SiO ₂ ) or magnesium oxide. It has a higher thermal conductivity than (MgO ₂ ) and has a thermal conductivity of 5 to several tens of times.

  The above ceramic materials are good because these ceramics can exist stably in the battery, do not adversely affect the battery reaction, and have a large volumetric heat capacity.

  The ceramic powder used in the present invention preferably has an average particle size of 0.1 μm to 2.5 μm. If the average particle size is less than 0.1 μm, the ceramic powder may agglomerate. On the other hand, when the average particle diameter exceeds 2.5 μm, appearance defects may occur in a battery having a laminate film as an exterior.

  In addition, as said ceramic powder, that whose particle size distribution is Gaussian distribution is preferable. Thereby, extremely large particles and small particles are not mixed in a large amount, and an advantage that productivity and battery characteristics are stabilized can be obtained.

  In the nonaqueous electrolyte of the present invention, the mixing ratio of the ceramic powder and the matrix polymer is preferably 1/1 or more and 6/1 or less, and more preferably 1/1 or more and 5/1 or less. It is more preferable. If the mixing ratio of the ceramic powder and the matrix polymer is less than 1/1, the effect of including the ceramic powder is small, and if it exceeds 6/1, battery characteristics such as cycle characteristics may be deteriorated.

Furthermore, in the non-aqueous electrolyte battery formed using the non-aqueous electrolyte of the present invention, the above-mentioned ceramic powder per unit area between the positive and negative electrodes, that is, in the non-aqueous electrolyte portion sandwiched between the positive and negative electrodes facing each other, It is preferably present at a rate of 0.6 mg / cm ² or more and 3.5 mg / cm ² or less per area defined by the positive electrode or negative electrode of the area. If it is less than 0.6 mg / cm ² , the effect of containing ceramic powder is small, and if it exceeds 3.5 mg / cm ² , battery characteristics such as cycle characteristics may not be sufficient.

Incidentally, abundance per area of the ceramic powder mentioned above, when each of the positive-side electrolyte and the negative side the electrolyte is, for example 0.6 mg / cm ^2, a 1.2 mg / cm ² as a whole non-aqueous electrolyte that It is.

[Nonaqueous solvent]
Examples of the nonaqueous solvent used in the nonaqueous electrolyte of the present invention include various high dielectric constant solvents and low viscosity solvents. As the high dielectric constant solvent, ethylene carbonate, propylene carbonate, and the like can be suitably used, but are not limited thereto, butylene carbonate, vinylene carbonate, 4-fluoro-1,3-dioxolan-2-one Cyclic carbonates such as (fluoroethylene carbonate), 4-chloro-1,3-dioxolan-2-one (chloroethylene carbonate), and trifluoromethylethylene carbonate can also be used.

  Further, as a high dielectric constant solvent, a lactone such as γ-butyrolactone and γ-valerolactone, a lactam such as N-methylpyrrolidone, and a cyclic carbamine such as N-methyloxazolidinone instead of or in combination with the cyclic carbonate. Sulfone compounds such as acid esters and tetramethylene sulfone can also be used.

  On the other hand, as the low-viscosity solvent, ethyl methyl carbonate and diethyl carbonate can be preferably used, but other than these, chain carbonates such as dimethyl carbonate and methyl propyl carbonate, methyl acetate, ethyl acetate, propion Chain carboxylic acid esters such as methyl acid, ethyl propionate, methyl butyrate, methyl isobutyrate, methyl trimethylacetate and ethyl trimethylacetate, chain amides such as N, N-dimethylacetamide, methyl N, N-diethylcarbamate and Chain carbamates such as ethyl N, N-diethylcarbamate and ethers such as 1,2-dimethoxyethane, tetrahydrofuran, tetrahydropyran and 1,3-dioxolane can be used.

  In the nonaqueous electrolyte of the present invention, the above-mentioned high dielectric constant solvent and low viscosity solvent can be used alone or in combination of two or more. Moreover, it is preferable that content of the above-mentioned non-aqueous solvent shall be 70 to 90 mass%. If it is less than 70% by mass, the viscosity may increase excessively, and if it exceeds 90% by mass, sufficient conductivity may not be obtained.

[Matrix polymer]
The non-aqueous electrolyte of the present invention contains a matrix polymer, and the matrix polymer is impregnated or held with an electrolyte salt, a non-aqueous solvent or ceramic powder. By such swelling, gelation or non-fluidization of the polymer compound, it is possible to effectively suppress leakage of the nonaqueous electrolyte in the obtained battery.

  Examples of the matrix polymer include polyvinyl formal (1), polyacrylic acid ester (2), and polyvinylidene fluoride (3) represented by the following chemical formulas (1) to (3). it can. Moreover, you may use the copolymer which has these materials as a main component.

  However, N in the formula (1) indicates the degree of polymerization, and preferably N = 100 to 10,000. If N is less than 100, gelation is not sufficient, and if it exceeds 10,000, the viscosity may be large and the capacity may be reduced.

In the formula (2), R represents C _n H _2n-1 O _m (n represents an integer of 1 to 8, m represents an integer of 0 to 4), N represents a degree of polymerization, and preferably N = 100 to 10,000. If N is less than 100, gelation is difficult, and if it exceeds 10,000, fluidity may decrease.

  However, N in the formula (3) indicates the degree of polymerization, and preferably N = 100 to 10,000. If N is less than 100, gelation is not sufficient, and if it exceeds 10,000, the viscosity may be large and the capacity may be reduced. When polyvinylidene fluoride is included in the matrix polymer, the matrix polymer preferably has a weight average molecular weight of 550000 or more. When the weight average molecular weight is less than 550000, the cycle characteristics may not be sufficient.

  In addition, it is preferable that content of the above-mentioned matrix polymer shall be 0.1-5 mass%. If it is less than 0.1% by mass, gelation is difficult, and it is difficult to hold the ceramic powder uniformly. If it exceeds 5% by mass, the battery characteristics may be affected, such as a decrease in energy density.

<Electrolyte salt>
The electrolyte salt used in the non-aqueous electrolyte of the present invention is not particularly limited as long as it dissolves or disperses in the non-aqueous solvent to generate ions, and a lithium salt such as lithium hexafluorophosphate (LiPF ₆ ) is preferably used. Needless to say, but not limited thereto. As the electrolyte salt, lithium hexafluorophosphate (LiPF ₆₎ other, lithium tetrafluoroborate (LiBF _4), lithium hexafluoroarsenate (LiAsF _6), lithium hexafluoro antimonate (LiSbF ₆₎ Inorganic lithium salts such as lithium perchlorate (LiClO ₄ ) and lithium tetrachloride aluminum oxide (LiAlCl ₄ ), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ), lithium bis (trifluoromethanesulfone) imide (LiN (CF ₃ SO ₂ ) ₂ ), lithium bis (pentafluoroethanesulfone) methide (LiC (C ₂ F ₅ SO ₂ ) ₂ ), lithium tris (trifluoromethanesulfone) methide (LiC (CF ₃ SO ₂ ) ₃ ), etc. Fluoroalkanesulfonic acid derivative lithium salts can also be used. In Germany or it is also possible to use a combination of two or more of them.

  In the case of lithium salt, the concentration of such an electrolyte salt is preferably 0.5 mol / kg or more and 2.1 mol / kg or less, and preferably 0.6 mol / kg or more and 2.0 mol / kg or less. More preferred. If it is less than 0.5 mol / kg, a high battery capacity may not be obtained due to a decrease in electrolyte components due to the addition of ceramic powder. Moreover, when it exceeds 2.1 mol / kg, the viscosity of an electrolyte solution becomes excessively high and good battery characteristics such as low temperature characteristics may not be obtained.

  The nonaqueous electrolyte of the present invention contains the ceramic powder, the matrix polymer, the nonaqueous solvent and the electrolyte salt as essential components as described above, but other components can be added thereto. Specifically, it can be combined with, for example, a carbonate having a multiple bond, and this can further improve the discharge capacity maintenance rate during repeated charge and discharge. The carbonic acid ester having a multiple bond is typically a carbonic acid ester having a carbon-carbon multiple bond (more typically, a carbon-carbon multiple bond (for example, a carbon-carbon double bond or a triple bond)). Of course, vinylene carbonate, which is an example), can be suitably used, but it goes without saying that the present invention is not limited thereto. That is, vinyl ethylene carbonate or the like can be used.

  And in the nonaqueous electrolyte of this invention, it is preferable that content of the carbonate ester which has the above-mentioned multiple bond shall be 0.05 mass% or more and 5 mass% or less, and 0.1 mass% or more and 3 mass% or less. More preferably, the content is 0.2% by mass or more and 2% by mass or less. If it is less than 0.05% by mass, there is no effect, and if it exceeds 5% by mass, the discharge capacity may decrease.

  In order to improve the dispersibility of the ceramic powder, the following surfactant may be used.

[Surfactant]
The surfactant is not particularly limited as long as it can disperse the ceramic powder, and preferred examples include hydrocarbon surfactants and silicone surfactants. Nonionic hydrocarbon surfactants and silicone surfactants are particularly desirable because they do not generate ions. Examples of the hydrocarbon surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, alkyl pyrrolidone (1-octyl-2-pyrrolidone, etc.), alkyl glucoside, sorbitan fatty acid ester, mono and diethanolamine fatty acid amide, alkyl Polyoxyethylene adduct of amine, ethoxylated tetramethyldodecine diol, tetramethyl decyne diol, glycerin fatty acid ester, pentaerythritol fatty acid ester, polyoxyethylene polyoxypropylene glycol, polyethylene glycol fatty acid ester, fatty acid polyoxyethylene sorbitan, etc. And nonionic hydrocarbon surfactants.

  Examples of the polyoxyethylene alkyl ether include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether and the like. Examples of the polyoxyethylene alkyl phenyl ether include polyoxyethylene octyl phenyl ether and polyoxyethylene nonyl phenyl ether. Furthermore, examples of the polyethylene glycol fatty acid ester include polyethylene glycol dilaurate and polyethylene glycol distearate.

  On the other hand, examples of silicone surfactants include dimethyl silicone, amino silane, acrylic silane, vinyl benzyl silane, vinyl benzyl amino silane, glycid silane, mercapto silane, dimethyl silane, polydimethyl siloxane, polyalkoxy siloxane, hydrodiene modified siloxane, vinyl. Modified siloxane, Vitroxy modified siloxane, Amino modified siloxane, Carboxyl modified siloxane, Halogenated modified siloxane, Epoxy modified siloxane, Methacryloxy modified siloxane, Mercapto modified siloxane, Fluorine modified siloxane, Alkyl group modified siloxane, Phenyl modified siloxane, Alkylene oxide modified siloxane, etc. And nonionic silicone surfactants.

  In addition, the above-mentioned hydrocarbon type surfactant and silicone type surfactant can be used individually by 1 type or in mixture of 2 or more types arbitrarily. Moreover, it is preferable that content of the above-mentioned surfactant shall be 0.3-5.0 mass parts with respect to 100 mass parts of above-mentioned fillers. When the content of the surfactant is within the above range, the strength (load) until a short circuit occurs can be further increased without substantially reducing the battery characteristics.

  Moreover, the nonaqueous electrolyte in this invention can be used regardless of a primary battery or a secondary battery.

2. Second Embodiment Next, the nonaqueous electrolyte battery of the present invention will be described.

(2-1) Configuration of Nonaqueous Electrolyte Battery FIG. 1 is an exploded perspective view showing an example of a laminated secondary battery as an embodiment of the nonaqueous electrolyte battery of the present invention. As shown in FIG. 1, this secondary battery is configured by enclosing a battery element 20 to which a positive electrode terminal 11 and a negative electrode terminal 12 are attached in a film-like exterior member 30. The positive electrode terminal 11 and the negative electrode terminal 12 are led out from the inside of the exterior member 30 to the outside, for example, in the same direction. The positive electrode terminal 11 and the negative electrode terminal 12 are each comprised by metal materials, such as aluminum (Al), copper (Cu), nickel (Ni), or stainless steel, for example.

  2 is a cross-sectional view taken along line II-II of battery element 20 shown in FIG. In the figure, a battery element 20 is formed by winding a positive electrode 21 and a negative electrode 22 facing each other with a non-aqueous electrolyte layer 23 and a separator 24 made of the non-aqueous electrolyte of the present invention interposed therebetween, The outermost periphery is protected by a protective tape 25.

[Exterior material]
The exterior member 30 is made of a rectangular laminate film in which, for example, a nylon film, an aluminum foil, and a polyethylene film are bonded together in this order. The exterior member 30 is disposed, for example, so that the polyethylene film side and the battery element 20 face each other, and the outer edge portions are joined to each other by fusion or adhesive.

  An adhesive film 31 for preventing the entry of outside air is inserted between the exterior member 30 and the positive electrode terminal 11 and the negative electrode terminal 12. The adhesion film 31 is made of a material having adhesion to the positive electrode terminal 11 and the negative electrode terminal 12. For example, when the positive electrode terminal 11 and the negative electrode terminal 12 are made of the metal materials described above, polyethylene, polypropylene, modified It is preferably composed of a polyolefin resin such as polyethylene or modified polypropylene.

  In addition, the exterior member 30 may be configured by another structure, for example, a laminate film having no metal material, a polymer film such as polypropylene, or a metal film, instead of the above-described laminate film.

Here, the general structure of a laminate film can be represented by the laminated structure of exterior layer / metal foil / sealant layer (however, the exterior layer and sealant layer may be composed of a plurality of layers), and the above. In this example, the nylon film corresponds to the exterior layer, the aluminum foil corresponds to the metal foil, and the polyethylene film corresponds to the sealant layer.
In addition, as metal foil, it is sufficient if it functions as a moisture-permeable barrier film, and not only aluminum foil but also stainless steel foil, nickel foil, and plated iron foil can be used. Thus, an aluminum foil excellent in workability can be suitably used.

  As the exterior member, usable configurations are listed in the form of (exterior layer / metal foil / sealant layer): Ny (nylon) / Al (aluminum) / CPP (unstretched polypropylene), PET (polyethylene terephthalate) / Al / CPP, PET / Al / PET / CPP, PET / Ny / Al / CPP, PET / Ny / Al / Ny / CPP, PET / Ny / Al / Ny / PE (polyethylene), Ny / PE / Al / LLDPE (direct) Chain low density polyethylene), PET / PE / Al / PET / LDPE (low density polyethylene), and PET / Ny / Al / LDPE / CPP.

[Positive electrode]
The positive electrode 21 has, for example, a structure in which a positive electrode active material layer 21B is coated on both surfaces or one surface of a positive electrode current collector 21A having a pair of opposed surfaces. The positive electrode current collector 21 </ b> A has a portion exposed without being covered with the positive electrode active material layer 21 </ b> B at one end portion in the longitudinal direction, and the positive electrode terminal 11 is attached to the exposed portion. The positive electrode current collector 21A is made of a metal foil such as an aluminum foil, a nickel foil, or a stainless steel foil.

  The positive electrode active material layer 21B includes one or more positive electrode materials capable of occluding and releasing lithium ions as a positive electrode active material, and a conductive agent and a binder as necessary. May be included.

Examples of the positive electrode material capable of inserting and extracting lithium ions include oxides such as vanadium oxide (V ₂ O ₅ ), titanium dioxide (TiO ₂ ), manganese dioxide (MnO ₂ ), sulfur (S), Lithium-free chalcogenides such as iron disulfide (FeS ₂ ), titanium disulfide (TiS ₂ ) and molybdenum disulfide (MoS ₂ ), and niobium diselenide (NbSe ₂ ) (particularly layered compounds and Spinel type compounds), lithium-containing compounds containing lithium, and conductive polymer compounds such as polyaniline, polythiophene, polyacetylene, and polypyrrole.

  Among these, lithium-containing compounds are preferable because some compounds can obtain a high voltage and a high energy density. Examples of such a lithium-containing compound include a composite oxide containing lithium and a transition metal element, and a phosphate compound containing lithium and a transition metal element. From the viewpoint of obtaining a higher voltage, cobalt is particularly preferred. (Co), nickel (Ni), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), chromium (Cr), vanadium (V), titanium (Ti) or any mixture thereof. The inclusion is preferred.

Such lithium-containing compounds are typically represented by the following general formula (4) or (5), the compound of the formula (4) generally has a layered structure, and the compound of the formula (5) is generally Has an olivine structure.
Li _r M ^I O ₂ (4)
Li _s M ^II PO ₄ (5)
(In formulas (4) and (5), M ^I and M ^II represent one or more transition metal elements, and the values of r and s vary depending on the charge / discharge state of the battery, but usually 0.05 ≦ r ≦ 1. .10, 0.05 ≦ s ≦ 1.10.

Specific examples of the composite oxide containing lithium and a transition metal element include lithium cobalt composite oxide (LiCoO ₂ ), lithium nickel composite oxide (LiNiO ₂ ), and solid solutions (Li (N _t Co _u Mn _v). ) O ₂ (0 <t <1, 0 <u <1, 0 <v <1, t + u + v = 1)), lithium nickel cobalt composite oxide (LiNi _1-w Co _w O ₂ (0 <w <1) ), Lithium manganese composite oxide having a spinel structure (LiMn ₂ O ₄ ), and a solid solution thereof (Li (Mn _2−x Ni _y ) O ₄ (0 <x <2, 0 <y <2)) Can be mentioned.

Specific examples of the phosphate compound containing lithium and a transition metal element include a lithium iron phosphate compound (LiFePO ₄ ) and a lithium iron manganese phosphate compound (LiFe _1-z Mn _z PO ₄ (0 <z <1)). These have the olivine structure described above.

  The conductive agent is not particularly limited as long as it can be mixed with an appropriate amount of the positive electrode active material to impart conductivity, and examples thereof include carbon materials such as graphite, carbon black, and ketjen black. These are used alone or in combination of two or more. In addition to the carbon material, a metal material or a conductive polymer material may be used as long as it is a conductive material.

  As a binder, the well-known binder normally used for the positive mix of this kind of battery can be used. Preferable examples include fluorine polymers such as polyvinyl fluoride, polyvinylidene fluoride and polytetrafluoroethylene, and synthetic rubbers such as styrene butadiene rubber, fluorine rubber and ethylene propylene diene rubber. These may be used alone or in combination of two or more.

[Negative electrode]
Similarly to the positive electrode 21, the negative electrode 22 has a structure in which a negative electrode active material layer 22 </ b> B is provided on both surfaces or one surface of a negative electrode current collector 22 </ b> A having a pair of opposed surfaces, for example. The negative electrode current collector 22A has an exposed portion without being provided with the negative electrode active material layer 22B at one end in the longitudinal direction, and the negative electrode terminal 12 is attached to the exposed portion. The negative electrode current collector 22A is made of a metal foil such as a copper foil, a nickel foil, or a stainless steel foil.

  The negative electrode active material layer 22B includes one or more of a negative electrode material capable of occluding and releasing lithium ions and metallic lithium as a negative electrode active material, and a conductive agent and a binder as necessary. An adhesive may be included. Examples of the negative electrode material capable of inserting and extracting lithium ions include carbon materials, metal oxides, and polymer compounds.

  Examples of the carbon material include non-graphitizable carbon materials, artificial graphite materials, graphite-based materials, and more specifically, pyrolytic carbons, cokes, graphites, glassy carbons, organic polymer compounds. There are fired bodies, carbon fibers, activated carbon, carbon black and the like. Among these, coke includes pitch coke, needle coke, petroleum coke and the like, and the organic polymer compound fired body is carbonized by firing a polymer material such as phenol resin or furan resin at an appropriate temperature. Say things.

  Examples of the metal oxide include iron oxide, ruthenium oxide, and molybdenum oxide. Examples of the polymer compound include polyacetylene and polypyrrole.

  Furthermore, examples of the negative electrode material capable of inserting and extracting lithium ions include a material containing at least one of a metal element and a metalloid element capable of forming an alloy with lithium as a constituent element. The negative electrode material may be a single element, alloy, or compound of a metal element or a metalloid element, or may have at least a part of one or more of these phases.

  In the present invention, the alloy includes an alloy containing one or more metal elements and one or more metalloid elements in addition to an alloy composed of two or more metal elements. Moreover, the nonmetallic element may be included. Some of the structures include a solid solution, a eutectic (eutectic mixture), an intermetallic compound, or a mixture of two or more of these.

  Examples of such metal elements or metalloid elements include tin (Sn), lead (Pb), magnesium (Mg), aluminum, indium (In), silicon (Si), zinc (Zn), antimony (Sb), Bismuth (Bi), gallium (Ga), germanium (Ge), arsenic (As), silver (Ag), hafnium (Hf), zirconium (Zr) and yttrium (Y) can be mentioned.

  Among them, a group 14 metal element or metalloid element in the long-period periodic table is preferable, and silicon or tin is particularly preferable. This is because silicon and tin have a large ability to occlude and release lithium, and a high energy density can be obtained.

  Examples of the tin alloy include silicon (Si), magnesium (Mg), nickel (Ni), copper (Cu), iron (Fe), cobalt (Co), manganese (Mn) as the second constituent element other than tin. ), Zinc (Zn), indium (In), silver (Ag), titanium (Ti), germanium (Ge), bismuth (Bi), antimony (Sb) and chromium (Cr). The thing containing is mentioned.

  As an alloy of silicon, for example, as a second constituent element other than silicon, tin, magnesium, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony and chromium are used. The thing containing at least 1 sort (s) of them is mentioned.

  Examples of the tin compound or silicon compound include those containing oxygen (O) or carbon (C), and may contain the second constituent element described above in addition to tin or silicon.

  Furthermore, the negative electrode material as described above may be an element that forms a composite oxide with lithium, such as titanium. Of course, metallic lithium may be precipitated and dissolved, and magnesium and aluminum other than lithium may be precipitated and dissolved.

  Note that as the conductive agent and the binder, the same materials as those used for the positive electrode can be used.

[Separator]
The separator 24 is made of an insulating thin film having a high ion permeability and a predetermined mechanical strength. Specifically, for example, a porous film made of a polyolefin-based synthetic resin such as polypropylene or polyethylene, or a porous film made of an inorganic material such as a ceramic non-woven fabric is used. It is good also as a laminated structure. In particular, those containing a polyolefin-based porous membrane are suitable because they have excellent separability between the positive electrode 21 and the negative electrode 22 and can further reduce internal short-circuiting and open circuit voltage reduction.

  The interior of the exterior member 30 is filled with the battery element 20 and a nonaqueous electrolyte made of the electrolyte composition.

[Configuration of non-aqueous electrolyte battery]
FIG. 3 is a schematic diagram showing a state of the battery element of the nonaqueous electrolyte battery shown in FIG. 1 with the nonaqueous electrolyte, and shows a state before the battery element is wound. In this case, the winding is performed, for example, by winding a laminated sheet of a separator, a positive electrode, and a negative electrode with S as the winding start end and E as the winding end.

  As shown in FIG. 3, there is an electrode between the positive electrode and the negative electrode between the negative electrode active material layer 22B provided on the negative electrode current collector 22A and the positive electrode active material layer 21B provided on the positive electrode current collector 21A. The positive electrode side electrolyte 23A and the negative electrode side electrolyte 23B of the present invention that mediate the inter-reaction are interposed (in the case where the positive electrode side and the negative electrode side are not particularly limited, they are appropriately referred to as nonaqueous electrolytes 23).

  The nonaqueous electrolyte 23 is preferably formed so as to protrude from each of the positive electrode active material layer 21B and the negative electrode active material layer 22B in a direction crossing the stacking direction. The protruding portion is formed with a width H of 0.1 mm or more and 2 mm or less from at least one side edge (not short edge) of the positive electrode active material layer 21B or the negative electrode active material layer 22B. It is preferable to cover the side edges of the active material layer 21B and the negative electrode active material layer 22B.

  The side edge portions of the positive electrode active material layer 21B and the negative electrode active material layer 22B are often cut portions during electrode manufacturing, and burrs may occur. And when this non-aqueous electrolyte 23 covers this side edge part, it becomes difficult to generate | occur | produce the short circuit caused by a burr | flash. In the present invention, since the non-aqueous electrolyte 23 contains ceramic powder, it is possible to reliably avoid such a short circuit.

  The width H of the nonaqueous electrolyte 23 protruding from the side edge of the positive electrode active material layer 21B or the negative electrode active material layer 22B is preferably 0.1 mm or more and 2 mm or less. If it is less than 0.1 mm, the short-circuit avoidance effect may be insufficient. Moreover, even if it is more than 2 mm, there is no sufficient difference in the effect.

  Further, the extending portion of the non-aqueous electrolyte 23 has a width of 0.1 mm or more and 5 mm or less (perpendicular to the paper surface) from one end (not long edge portion) without the positive electrode active material layer 21B or the negative electrode active material layer 22B. It is preferable that the width of the positive electrode active material layer 21 </ b> B and the negative electrode active material layer 22 </ b> B is covered with a width in a certain direction (not shown).

  The ends of the positive electrode active material layer 21B and the negative electrode active material layer 22B are application start portions for applying a positive electrode mixture containing a positive electrode active material and a negative electrode mixture containing a negative electrode active material. There may be a step at the end of the material layer 22B. At this time, a short circuit is likely to occur at the stepped portion. Then, since the end portion is covered with each of the positive electrode side electrolyte 23A and the negative electrode side electrolyte 23B, a short circuit due to a step is less likely to occur. In this invention, since the positive electrode side electrolyte 23A and the negative electrode side electrolyte 23B contain ceramic powder, it is possible to avoid such a short circuit satisfactorily.

  The width of the nonaqueous electrolyte 23 protruding from the end portions of the positive electrode active material layer 21B and the negative electrode active material layer 22B is preferably 0.1 mm or more and 5 mm or less. If it is less than 0.1 mm, the short-circuit avoidance effect may be insufficient. Moreover, even if it is more than 5 mm, there is not a sufficient difference in the effect. In the winding state, the protrusion of the end portion can be confirmed in the vicinity of the winding start end S and the winding end E, and the protrusion of the side edge portion can be confirmed in the extending portions of the positive electrode lead and the negative electrode lead.

  In the nonaqueous electrolyte battery of the present invention, since the ceramic powder is mixed so that the negative electrode side electrolyte 23B has a higher thermal conductivity than the positive electrode side electrolyte 23A, heat is diffused in the negative electrode 22 as compared with the positive electrode 21. It becomes easy and can improve safety.

(2-2) Method for Manufacturing Nonaqueous Electrolyte Battery Next, an example of a method for manufacturing the so-called laminate-type nonaqueous electrolyte battery described above will be described.

[Production of positive electrode]
For example, when a particulate active material is used as the positive electrode active material, a positive electrode mixture is prepared by mixing the positive electrode active material with a conductive agent and a binder as necessary, and N-methyl-2-pyrrolidone. A positive electrode mixture slurry is prepared by dispersing in a dispersion medium. Next, the positive electrode mixture slurry is applied to both surfaces of the belt-like positive electrode current collector 21A, dried, and compression-molded to form the positive electrode active material layer 21B on the positive electrode current collector 21A.

[Production of negative electrode]
For example, when a particulate active material is used as the negative electrode active material, a negative electrode mixture is prepared by mixing the negative electrode active material and, if necessary, a conductive agent and a binder, and N-methyl-2-pyrrolidone. A negative electrode mixture slurry is prepared by dispersing in a dispersion medium such as Next, the negative electrode mixture slurry is applied to both surfaces of the negative electrode current collector 22A, dried, and compression-molded to form the negative electrode active material layer 22B on the negative electrode current collector 22A.

[Preparation of non-aqueous electrolyte composition]
For example, dimethyl carbonate (DMC) is mixed and stirred as a non-aqueous solvent, matrix polymer, ceramic powder, and a viscosity adjusting solvent. Moreover, you may make it add surfactant with these materials.

  At this time, the nonaqueous electrolyte composition provided on the surface of the negative electrode 22 is mixed with ceramic powder having a higher thermal conductivity than the ceramic powder mixed with the nonaqueous electrolyte composition provided on the surface of the positive electrode 21. To do. In addition, when the same ceramic powder is mixed in each of the nonaqueous electrolyte composition to be provided on the surface of the negative electrode 22 and the nonaqueous electrolyte composition to be provided on the surface of the positive electrode 21, it is provided on the surface of the negative electrode 22. The amount of ceramic powder added to the non-aqueous electrolyte composition is increased. Further, when two or more kinds of ceramic powders are mixed and used, the ceramic powder to the non-aqueous electrolyte composition provided on the surface of the negative electrode 22 has a higher thermal conductivity as a whole.

[Preparation of non-aqueous electrolyte battery]
A nonaqueous electrolyte composition in which ceramic powder is mixed is applied to the surfaces of the positive electrode 21 and the negative electrode 22 produced as described above, and then dried, and the viscosity adjusting solvent is volatilized to form a nonaqueous electrolyte layer. At this time, the nonaqueous electrolyte composition is preferably applied so as to cover the positive electrode active material layer 21B and the negative electrode active material layer 22B and to protrude from the side edges of the positive electrode active material layer 21B and the negative electrode active material layer 22B. . Thereafter, the positive electrode, the separator, the negative electrode, and another separator are aligned and wound in the longitudinal direction to obtain a battery element.

  Next, the battery element described above is packaged with a laminate film, and the periphery of the battery element is sealed by welding to produce a nonaqueous electrolyte battery.

  In the case of producing a non-aqueous electrolyte battery having a gel electrolyte layer, a battery in which a positive electrode 21, a negative electrode 22 and a separator 13 coated with a polymer compound monomer or polymer solution such as polyvinylidene fluoride are applied to the surface is wound. An element may be used. That is, the gel electrolyte layer can be formed by injecting a liquid non-aqueous electrolyte after housing the battery element in the exterior member 30.

  In the secondary battery described above, when charged, lithium ions are released from the positive electrode active material layer 21 </ b> B and inserted into the negative electrode active material layer 22 </ b> B through the nonaqueous electrolyte layer 23. When discharge is performed, lithium ions are released from the negative electrode active material layer 22 </ b> B and inserted into the positive electrode active material layer 21 </ b> B through the nonaqueous electrolyte layer 23.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

[Example 1]
In Example 1, a nonaqueous electrolyte battery was produced by changing the material of ceramic powder, the amount added, and the amount of ceramic powder per unit area of the electrode, and the battery characteristics were evaluated.

<Example 1-1>
[Production of positive electrode]
91 parts by mass of lithium cobalt oxide (LiCoO ₂ ) as a positive electrode active material, 6 parts by mass of graphite as a conductive agent, and 10 parts by mass of polyvinylidene fluoride (PVdF) as a binder are mixed uniformly. -Dispersed in methyl-2-pyrrolidone (NMP) to obtain a positive electrode mixture slurry.

  Next, the obtained positive electrode mixture slurry was uniformly applied to both surfaces of a 20 μm-thick strip-shaped aluminum foil serving as a positive electrode current collector, and dried to form a positive electrode active material layer. This was cut into a shape having a width of 38 mm and a length of 700 mm to produce a positive electrode, and a positive electrode terminal was further attached.

[Production of negative electrode]
90 parts by mass of artificial graphite as a negative electrode active material and 10 parts by mass of PVdF as a binder were homogeneously mixed and dispersed in NMP to obtain a negative electrode mixture slurry. Next, the obtained negative electrode mixture slurry was uniformly applied on both surfaces of a 10 μm-thick strip-shaped copper foil serving as a negative electrode current collector, and dried to form a negative electrode mixture layer. This was cut into a shape having a width of 40 mm and a length of 650 mm to produce a negative electrode, and a negative electrode terminal was further attached.

[Preparation of positive electrode-side non-aqueous electrolyte material]
As the positive electrode-side nonaqueous electrolyte material, 90 parts by mass of a nonaqueous electrolyte and a polyvinylidene fluoride-hexafluoropropylene copolymer (PVdF: HFP = 93.1: 6.9 (mass ratio)) as a matrix polymer 10 The mass part was mixed. To this mixed material, aluminum oxide (Al ₂ O ₃ ) having an average particle size of 0.1 μm is added as ceramic powder so that ceramic powder: matrix polymer = 1: 1, and further a viscosity adjusting solvent. The viscosity was adjusted to 50 mPa · s by adding dimethyl carbonate (DMC). At this time, the weight average molecular weight of the polyvinylidene fluoride-hexafluoropropylene copolymer as the matrix polymer was 60 × 10 ⁴ .

The non-aqueous electrolyte is a non-aqueous solvent in which ethylene carbonate (EC) and propylene carbonate (PC) are mixed at a ratio of ethylene carbonate (EC): propylene carbonate (PC) = 6: 4 (mass ratio). Then, lithium hexafluorophosphate (LiPF ₆ ) as an electrolyte salt dissolved in a concentration of 1.0 mol / kg was used.

  Further, since dimethyl carbonate (DMC) is finally volatilized, it does not remain in the battery.

[Preparation of non-aqueous electrolyte material for negative electrode]
The negative electrode-side nonaqueous electrolyte material was produced in the same manner as the positive electrode-side nonaqueous electrolyte material except that silicon carbide (SiO) having an average particle size of 0.1 μm was used as the ceramic powder. The ratio of the positive electrode side ceramic powder (Al ₂ O ₃ ) and the negative electrode side ceramic powder (SiC) was 1: 1.

[Preparation of non-aqueous electrolyte battery]
The non-aqueous electrolyte material described above was applied to both the positive electrode and the negative electrode, and the solvent was volatilized to form a gel electrolyte layer. In this case, the ceramic powder in the gel electrolyte, the positive-side electrolyte layer, 0.6 mg / cm ² per unit area of the positive or negative electrode in each of the anode-side electrolyte layer, i.e. was 1.2 mg / cm ² as a whole. The positive electrode and the negative electrode were laminated and wound up via a separator made of a microporous polyethylene film having a thickness of 12 μm to obtain a flat wound battery element. Thereafter, the battery element was enclosed in an exterior member made of an aluminum laminate film to obtain a flat type nonaqueous electrolyte battery.

  Table 1 shows a part of the specifications of the obtained nonaqueous electrolyte battery.

<Example 1-2> to <Example 1-9>, <Comparative Example 1-2> to <Comparative Example 1-6>
For each of the positive electrode side electrolyte layer and the negative electrode side electrolyte layer, Example 1 except that the ceramic powder material and the ratio of the ceramic powder contained in the positive electrode side electrolyte layer and the negative electrode side electrolyte layer were changed as shown in Table 1 below. A nonaqueous electrolyte battery was produced in the same manner as in Example-1.

<Example 1-10> and <Example 1-11>, <Comparative Example 1-7> and <Comparative Example 1-8>
For each of the positive electrode side electrolyte layer and the negative electrode side electrolyte layer, a nonaqueous electrolyte battery was produced in the same manner as in Example 1-1 except that the material of the ceramic powder contained was changed as shown in Table 1 below.

<Example 1-12> and <Example 1-13>
A nonaqueous electrolyte battery was fabricated in the same manner as in Example 1-1 except that the ceramic powder was not added to the positive electrode side electrolyte layer and the ceramic powder of the negative electrode side electrolyte layer was changed to the material shown in Table 1 below.

<Example 1-14> and <Example 1-15>, <Comparative Example 1-9> and <Comparative Example 1-10>
As shown in Table 1 below, a nonaqueous electrolyte battery was produced in the same manner as in Example 1-1 except that the amount of the ceramic powder per unit area of the positive electrode or the negative electrode was changed.

[Battery evaluation]
The following performance evaluation was performed on the battery of each example obtained as described above, and the results obtained are shown in Table 1 and Table 2.

(A) Nail penetration test A 3 mm diameter nail was pierced in the center of the main surface of each of the nonaqueous electrolyte batteries of Examples and Comparative Examples heated to 95 ° C. to confirm the presence or absence of gas ejection. When there was no gas ejection, the charging voltage of the nonaqueous electrolyte battery was gradually increased to confirm the limit charging voltage at which no gas ejection occurred.

(B) Cycle characteristics The nonaqueous electrolyte batteries of the examples and comparative examples were charged at a constant current until the battery voltage became 4.2 V at a charging current of 1 C in a 23 ° C. environment, and then at a charging voltage of 4.2 V. Low voltage charging was performed for 1.5 hours. Thereafter, discharging was performed at a discharge current of 1 C until the battery voltage reached 3.0 V, and the discharge capacity at this time was determined as the initial capacity.

Subsequently, 400 cycles of charging and discharging were performed under the same conditions as described above, and the discharge capacity at the time of discharging at the 400th cycle was determined. Note that 1C is a current value at which the theoretical capacity of the nonaqueous electrolyte battery can be released in one hour. Furthermore, the discharge capacity maintenance rate in the 400th cycle was calculated from the following formula.
Discharge capacity maintenance ratio [%] = (discharge capacity at 400th cycle / initial capacity) × 100

  The evaluation results are shown in Table 1 below.

  As can be seen from Table 1, Comparative Example 1-1, which does not contain ceramic powder in the gel electrolyte layer, has a limit voltage at the time of nail penetration test as compared with Examples and other comparative examples containing ceramic powder in the gel electrolyte layer. It became low. Further, Comparative Examples 2 to 4 in which ceramic powder having high thermal conductivity was mixed in the positive electrode side electrolyte layer, and Comparative Example 1-5 in which the same ceramic powder was mixed in each of the positive electrode side electrolyte layer and the negative electrode side electrolyte layer, and In Comparative Example 1-6, although the limit voltage in the nail penetration test was improved as compared with Comparative Example 1-1, it was less than or equal to that in each Example.

  On the other hand, when ceramic powder with high thermal conductivity is mixed in the negative electrode side electrolyte layer as in Example 1-1 to Example 1-9, the capacity retention rate is slightly reduced as compared with Comparative Example 1. However, the limit voltage in the nail penetration test could be remarkably improved. Similar results were obtained in Examples 1-12 to 1-13 in which ceramic powder was added only to the negative electrode side electrolyte layer.

  In addition, even when the same ceramic powder is used for each of the positive electrode side electrolyte layer and the negative electrode side electrolyte layer, the amount of addition to the negative electrode side electrolyte layer is made larger than the addition amount to the positive electrode side electrolyte layer, so that the nail penetration test is performed. The result could be improved.

Furthermore, as can be seen from Example 1-14, Example 1-15, Comparative Example 1-9 and Comparative Example 1-10, the amount of ceramic powder per unit area of the electrode is 0.6 mg / cm ² or more. When it was 5 mg / cm ² or less, both safety and cycle characteristics could be achieved.

[Example 2]
In Example 2, a non-aqueous electrolyte battery was prepared by using two kinds of ceramic powders mixed with the ceramic powder added to the positive electrode side electrolyte layer and the negative electrode side electrolyte layer, and the battery characteristics were evaluated.

<Example 2-1>
As the ceramic powder to be mixed in the negative electrode side electrolyte layer, non-aqueous solution was used in the same manner as in Example 1-1 except that a material in which silicon carbide (SiC) and aluminum oxide (Al ₂ O ₃ ) were mixed at a ratio of 2: 1 was used. An electrolyte battery was produced. The ratio of the mixing amount of the total mixing amount of silicon carbide in the negative electrode electrolyte layer (SiC) and aluminum oxide (Al ₂ O _3), aluminum oxide in the positive electrode side electrolyte layer (Al ₂ O ₃₎ is 1: 1 On average, the thermal conductivity of the ceramic powder mixed in the negative electrode side electrolyte layer was increased.

<Example 2-2>
As the ceramic powder to be mixed in the negative electrode side electrolyte layer, a material obtained by mixing silicon carbide (SiC) and aluminum oxide (Al ₂ O ₃ ) at 1: 1 was used in the same manner as in Example 1-1. A water electrolyte battery was prepared. The ratio of the mixing amount of the total mixing amount of silicon carbide in the negative electrode electrolyte layer (SiC) and aluminum oxide (Al ₂ O _3), aluminum oxide in the positive electrode side electrolyte layer (Al ₂ O ₃₎ is 1: 1 On average, the thermal conductivity of the ceramic powder mixed in the negative electrode side electrolyte layer was increased.

<Example 2-3>
As ceramic powder to be mixed with the positive-side electrolyte layer, and an aluminum oxide (Al ₂ O ₃₎ and zirconium oxide (ZrO ₂₎ 1: except for using mixed material 1, in the same manner as in Example 1-1 A nonaqueous electrolyte battery was produced. The ratio of the total amount of aluminum oxide (Al ₂ O ₃ ) and zirconium oxide (ZrO ₂ ) in the positive electrode side electrolyte layer to the amount of silicon carbide (SiC) in the negative electrode side electrolyte layer is 1: 1. The average thermal conductivity of the ceramic powder mixed in the negative electrode side electrolyte layer was increased.

<Example 2-4>
As a ceramic powder mixed with the positive electrode side electrolyte layer, a material in which aluminum oxide (Al ₂ O ₃ ) and zirconium oxide (ZrO ₂ ) are mixed at a ratio of 1: 1 is used. A nonaqueous electrolyte battery was fabricated in the same manner as in Example 1-1 except that a material in which aluminum (Al ₂ O ₃ ) and silicon carbide (SiC) were mixed at a ratio of 1: 1 was used. The total mixing amount of aluminum oxide (Al ₂ O ₃ ) and zirconium oxide (ZrO ₂ ) in the positive electrode side electrolyte layer, and the total mixing amount of aluminum oxide (Al ₂ O ₃ ) and silicon carbide (SiC) in the negative electrode side electrolyte layer The ratio of the amount was 1: 1, and on average, the thermal conductivity of the ceramic powder mixed in the negative electrode side electrolyte layer was increased.

<Comparative Example 2-1>
As a ceramic powder mixed in the positive electrode side electrolyte layer, a material in which aluminum oxide (Al ₂ O ₃ ) and silicon carbide (SiC) are mixed at a ratio of 1: 1 is used, and as a ceramic powder mixed in the negative electrode side electrolyte layer, aluminum oxide is used. A nonaqueous electrolyte battery was produced in the same manner as in Example 1-1 except that (Al ₂ O ₃ ) was used. The ratio of the total amount of aluminum oxide (Al ₂ O ₃ ) and silicon carbide (SiC) in the positive electrode side electrolyte layer to the amount of aluminum oxide (Al ₂ O ₃ ) in the negative electrode side electrolyte layer is 1: 1. On average, the thermal conductivity of the ceramic powder mixed in the positive electrode side electrolyte layer was increased.

<Comparative Example 2-2>
Silicon carbide (SiC) is used as the ceramic powder to be mixed with the positive electrode side electrolyte layer, silicon ceramic (SiC) and aluminum oxide (as the ceramic powder to be mixed with the negative electrode side electrolyte layer are used as ceramic powder to be mixed with the negative electrode side electrolyte layer ( A nonaqueous electrolyte battery was produced in the same manner as in Example 1-1 except that a material in which Al ₂ O ₃ ) was mixed at 1: 1 was used. In addition, the ratio of the mixing amount of silicon carbide (SiC) in the positive electrode side electrolyte layer and the mixing amount of silicon carbide (SiC) and aluminum oxide (Al ₂ O ₃ ) in the negative electrode side electrolyte layer is 1: 1, and the average Thus, the thermal conductivity of the ceramic powder mixed in the positive electrode side electrolyte layer was increased.

<Comparative Example 2-3>
As a ceramic powder to be mixed with the positive electrode side electrolyte layer, a material in which aluminum oxide (Al ₂ O ₃ ) and silicon carbide (SiC) are mixed at a ratio of 1: 1 is used. The nonaqueous electrolyte is the same as in Example 1-1, except that a material in which silicon carbide (SiC) and aluminum oxide (Al ₂ O ₃ ) are mixed at 1: 1 is used as the ceramic powder to be mixed in the electrolyte layer. A battery was produced. The total amount of aluminum oxide (Al ₂ O ₃ ) and silicon carbide (SiC) in the positive electrode side electrolyte layer, and the amount of silicon carbide (SiC) and aluminum oxide (Al ₂ O ₃ ) in the negative electrode side electrolyte layer Of the ceramic powder mixed with the positive electrode side electrolyte layer was made high on average.

[Battery evaluation]
(A) Nail penetration test (b) Cycle characteristics In the same manner as in Example 1, the above-described battery evaluation was performed.

  The results are shown in Table 2 below.

  As can be seen from Table 2, even when a plurality of ceramic powders were mixed, high safety could be obtained by increasing the average thermal conductivity of the ceramic powder mixed in the negative electrode side electrolyte layer.

[Example 3]
In Example 3, the positive electrode active material was changed to lithium nickelate, and the same evaluation as in Example 1 was performed.

<Example 3-1> to <Example 3-15> and <Comparative Example 3-1> to <Comparative Example 3-10>
<Example 1-1> to <Example 1-15> and <Comparative Example 1-1> to <Comparative Example 1-10>, respectively, except that lithium nickelate (LiNiO ₂ ) was used as the positive electrode active material Similarly, a non-aqueous electrolyte battery was produced.

[Battery evaluation]
(A) Nail penetration test (b) Cycle characteristics In the same manner as in Example 1, the above-described battery evaluation was performed.

  The results are shown in Table 3 below.

  As can be seen from Table 3, the thermal conductivity of the ceramic powder mixed in the negative electrode side electrolyte layer is increased even when lithium nickelate having a large gas generation amount relative to lithium cobaltate is used as the positive electrode active material. Therefore, high safety could be obtained.

[Example 4]
In Example 4, the positive electrode active material was changed to lithium nickelate, and the same evaluation as in Example 2 was performed.

<Example 4-1> to <Example 4-4> and <Comparative Example 4-1> to <Comparative Example 4-3>
<Example 2-1> to <Example 2-4> and <Comparative Example 2-1> to <Comparative Example 2-3>, respectively, except that lithium nickelate (LiNiO ₂ ) was used as the positive electrode active material. Similarly, a non-aqueous electrolyte battery was produced.

[Battery evaluation]
(A) Nail penetration test (b) Cycle characteristics In the same manner as in Example 1, the above-described battery evaluation was performed.

  The results are shown in Table 4 below.

  As can be seen from Table 4, even when lithium nickelate having a large amount of gas generation relative to lithium cobaltate is used as the positive electrode active material, the thermal conductivity of the ceramic powder mixed on the negative electrode side electrolyte layer on average By increasing the height, high safety could be obtained.

  As mentioned above, although this invention was demonstrated with some embodiment and an Example, this invention is not limited to these, A various deformation | transformation is possible within the range of the summary of this invention.

  For example, in the above embodiment, the case where a battery element in which a positive electrode and a negative electrode are stacked and wound is described, but a flat battery element in which a pair of positive electrodes and negative electrodes are stacked, or a plurality of positive electrodes and negative electrodes The present invention can also be applied to a case where a laminated battery element in which is stacked.

  In addition, the present invention relates to a battery using lithium as an electrode reactant as described above, but the technical idea of the present invention is that other alkali metals such as sodium (Na) or potassium (K), magnesium ( The present invention can also be applied to the case of using an alkaline earth metal such as Mg) or calcium (Ca), or another light metal such as aluminum.

DESCRIPTION OF SYMBOLS 11 ... Positive electrode terminal 12 ... Negative electrode terminal 20 ... Battery element 21 ... Positive electrode 21A ... Positive electrode collector 21B ... Positive electrode active material layer 21a ... Electrode surface part 21b ... Electrode inside 22 ... Negative electrode 22A ... Negative electrode collector 22B ... Negative electrode active material Layer 23 ... non-aqueous electrolyte (layer)
23A ... Positive electrode side electrolyte 23B ... Negative electrode side electrolyte 24 ... Separator 25 ... Protective tape 30 ... Exterior member 31 ... Adhesive film

Claims (20)

A nonaqueous electrolyte for a positive electrode comprising an electrolyte salt, a nonaqueous solvent, and a matrix polymer;
A negative electrode non-aqueous electrolyte containing an electrolyte salt, a non-aqueous solvent, and a matrix polymer,
The thermal conductivity of the ceramic powder contained in the non-aqueous electrolyte for negative electrode is greater than the thermal conductivity of the ceramic powder contained in the non-aqueous electrolyte for positive electrode, or the content of ceramic powder in the non-aqueous electrolyte for negative electrode However, the nonaqueous electrolyte composition is more than the content of the ceramic powder in the nonaqueous electrolyte for positive electrode . The non-aqueous electrolyte composition according to claim 1 , wherein ceramic powder is contained only in the non-aqueous electrolyte for a negative electrode . The ceramic powder is made of aluminum oxide (Al ₂ O ₃ ), zirconium oxide (ZrO), titanium oxide (TiO ₂ ), silicon oxide (SiO ₂ ), magnesium oxide (MgO ₂ ), silicon carbide (SiC), boron nitride ( The nonaqueous electrolyte composition according to claim 1 or 2, which is at least one selected from the group consisting of BN) and aluminum nitride (AlN). The nonaqueous electrolyte composition according to any one of claims 1 to 3 mean particle size of the ceramic powder is 0.1μm or more 2.5μm or less. The non-aqueous electrolyte composition according to any one of claims 1 to 4, wherein a mixing amount per unit area of the ceramic powder is 0.6 mg / cm ² or more and 3.5 mg / cm ² or less. A positive electrode;
A negative electrode,
A separator disposed between the positive electrode and the negative electrode;
An electrolyte salt, a non-aqueous solvent, and a matrix polymer, the positive electrode non-aqueous electrolyte formed on the surface of the positive electrode, an electrolyte salt, a non-aqueous solvent, and a matrix polymer, and a negative electrode for non-aqueous electrolyte formed on the surface,
The thermal conductivity of the ceramic powder contained in the non-aqueous electrolyte for negative electrode is greater than the thermal conductivity of the ceramic powder contained in the non-aqueous electrolyte for positive electrode, or the content of ceramic powder in the non-aqueous electrolyte for negative electrode However, the nonaqueous electrolyte battery has a larger content of ceramic powder in the nonaqueous electrolyte for positive electrode . Ceramic powder is contained only in the non-aqueous electrolyte for the negative electrode.
The nonaqueous electrolyte battery according to claim 6. The ceramic powder is made of aluminum oxide (Al ₂ O ₃ ), zirconium oxide (ZrO), titanium oxide (TiO ₂ ), silicon oxide (SiO ₂ ), magnesium oxide (MgO ₂ ), silicon carbide (SiC), boron nitride ( The nonaqueous electrolyte battery according to claim 6 or 7, which is at least one selected from the group consisting of BN) and aluminum nitride (AlN). The nonaqueous electrolyte battery according to any one of claims 6 to 8, wherein the ceramic powder has an average particle size of 0.1 µm to 2.5 µm. The non-aqueous electrolyte battery according to any one of claims 6 to 9, wherein a mixing amount per unit area of the ceramic powder is 0.6 mg / cm ² or more and 3.5 mg / cm ² or less. The thermal conductivity of the ceramic powder contained in the non-aqueous electrolyte for the negative electrode, according to any one of claims 6 to 10 is more than twice the thermal conductivity of the ceramic powder contained in the non-aqueous electrolyte for the positive electrode Non-aqueous electrolyte battery. The nonaqueous electrolyte battery according to any one of claims 6 to 11, wherein a particle size distribution of the ceramic powder is a Gaussian distribution.   In at least one of the positive electrode and the negative electrode, the mixing ratio of the ceramic powder and the matrix polymer is 1/1 or more and 5/1 or less by mass ratio.
The nonaqueous electrolyte battery according to claim 6.   The matrix polymer contains one of polyvinyl formal (1), polyacrylate (2), and polyvinylidene fluoride (3) represented by the following chemical formulas (1) to (3):
The nonaqueous electrolyte battery according to claim 6.

However, N in Formula (1) shows a polymerization degree and is N = 100-10000.

However, R in the formula (2) is C _n H _2n-1 O _m (N represents an integer of 1 to 8, m represents an integer of 0 to 4.) N represents a degree of polymerization, and N = 100 to 10,000.

However, N in (3) Formula shows a polymerization degree, and is N = 100-10000.   The positive and negative electrode binders are fluoropolymers.
The nonaqueous electrolyte battery according to claim 6.   The matrix polymer contains polyvinylidene fluoride, and the polyvinylidene fluoride has a weight average molecular weight of 550000 or more.
The nonaqueous electrolyte battery according to any one of claims 6 to 15. The matrix polymer is a polyvinylidene fluoride-hexafluoropropylene copolymer
The nonaqueous electrolyte battery according to claim 6. When the concentration of the electrolyte salt is a lithium salt, it is 0.5 mol / kg or more and 2.1 mol / kg or less.
The nonaqueous electrolyte battery according to any one of claims 6 to 17. The surfactant contained in the positive electrode nonaqueous electrolyte and / or the negative electrode nonaqueous electrolyte is a hydrocarbon surfactant or a silicone surfactant.
The nonaqueous electrolyte battery according to any one of claims 6 to 18. The positive electrode is a composite oxide containing lithium and a transition metal element, or a phosphate compound containing lithium and a transition metal element
The nonaqueous electrolyte battery according to any one of claims 6 to 19.

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