JP5987494B2 - Electricity storage element - Google Patents

Description

  The present invention relates to a power storage device that includes a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and a non-aqueous electrolyte containing an electrolyte salt.

  The shift from gasoline cars to electric cars has become important as a global environmental problem. For this reason, development of an electric vehicle using a power storage element such as a lithium ion secondary battery as a power source is being promoted.

  A lithium ion secondary battery includes a positive electrode and a negative electrode, a separator is interposed between the positive electrode and the negative electrode, and has a basic configuration including a non-aqueous electrolyte, and further interposed between the positive electrode and the negative electrode. A power storage element having an inorganic layer in the separator is proposed (see, for example, Patent Document 1). According to this, an inorganic filler is applied to the separator to form an inorganic layer, thereby ensuring the heat resistance of the separator, thereby improving safety such as preventing an internal short circuit during use.

JP 2010-240936 A

  However, in the conventional power storage element having an inorganic layer in the separator between the positive electrode and the negative electrode, the inorganic layer is peeled off during use of the power storage element, so that a micro short circuit may occur. In particular, in medium- and large-sized power storage elements with high output and high capacity, the use area is large, and thus the probability of occurrence of the micro short-circuit may be increased. For this reason, it is a subject that a yield falls.

  The present invention has been made to solve the above problems, and in a power storage element having an inorganic layer between at least one of a positive electrode and a negative electrode and a separator, occurrence of a micro short circuit due to separation of the inorganic layer. An object is to provide a power storage element that can be suppressed (yield can be improved).

  In order to achieve the above object, a power storage device according to one embodiment of the present invention includes a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and a nonaqueous electrolyte containing an electrolyte salt. An inorganic filler layer containing inorganic particles is disposed between at least one of the positive electrode and the negative electrode and the separator, and the inorganic particles are selected from the group consisting of calcium, sodium, and titanium. An aluminum silicate compound containing at least one selected element is provided, and the electrolyte salt includes a salt containing fluorine.

  It has been found that the occurrence of a micro short circuit can be suppressed in the configuration of the power storage element. That is, when the electrolyte salt contains a salt containing fluorine and the water concentration in the electricity storage device is 1000 ppm or less, a small amount of hydrogen fluoride (HF) is generated in the electricity storage device, and the aluminum silicate compound is The constituent silica dissolves in the HF. And the said silica reacts with the at least 1 sort (s) of element chosen from the group which consists of calcium, sodium, and titanium contained in an aluminum silicate compound, and a part of inorganic layers are bound together by recrystallization. Suppresses inorganic layer detachment. Accordingly, in a power storage element having an inorganic layer between at least one of the positive electrode and the negative electrode and the separator, occurrence of a micro short circuit due to separation of the inorganic layer can be suppressed. As a result, the yield at the time of production of the electricity storage device can be improved.

  In addition, the abundance of at least one element selected from the group consisting of calcium, sodium and titanium contained in the inorganic particles is 0.01 at% with respect to the abundance of all the metal elements present in the inorganic particles. It may be more than 5 at%.

  Accordingly, in a power storage element having an inorganic layer between at least one of the positive electrode and the negative electrode and the separator, occurrence of a micro short circuit due to separation of the inorganic layer can be suppressed. As a result, the yield at the time of production of the electricity storage device can be improved.

  The moisture concentration in the electricity storage element defined by the amount of moisture relative to the weight of the electricity storage element may be 10 ppm or more.

  Accordingly, in a power storage element having an inorganic layer between at least one of the positive electrode and the negative electrode and the separator, occurrence of a micro short circuit due to separation of the inorganic layer can be suppressed. As a result, the yield at the time of production of the electricity storage device can be improved.

  The inorganic filler layer may be provided on the separator.

  According to this, since the inorganic filler layer is provided on the separator in the electricity storage device, the inorganic filler layer can be disposed between the positive electrode and the negative electrode with a simple configuration.

The salt having fluorine contained in the electrolyte salt may be LiPF ₆ .

As a salt having fluorine contained in the electrolyte salt, it is more preferable in practical use to use LiPF ₆ which is electrically stable and has high ionic conductivity.

  According to the present invention, in a power storage element having an inorganic layer between at least one of a positive electrode and a negative electrode and a separator, occurrence of a micro short circuit due to separation of the inorganic layer can be suppressed.

It is an external appearance perspective view of the electrical storage element which concerns on embodiment of this invention. It is a perspective view which shows the structure of the electrode body which concerns on embodiment of this invention. It is sectional drawing which shows the structure of the electrode body which concerns on embodiment of this invention. It is sectional drawing which shows the structure of the separator which concerns on embodiment of this invention. It is a figure which shows an example of the XRD measurement result of the inorganic particle contained in the inorganic filler layer which concerns on embodiment of this invention.

  Hereinafter, a power storage device according to an embodiment of the present invention will be described with reference to the drawings. Each of the embodiments described below shows a preferred specific example of the present invention. Numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of constituent elements, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept of the present invention are described as optional constituent elements that constitute a more preferable embodiment.

  First, the configuration of the power storage element 10 will be described.

  FIG. 1 is an external perspective view of a power storage device 10 according to an embodiment of the present invention. In addition, the figure is a figure which saw through the container inside. FIG. 2 is a perspective view showing the configuration of the electrode body 400 according to the embodiment of the present invention. In addition, the same figure is the figure which expanded partially the winding state of the electrode body 400 shown in FIG.

The power storage element 10 is a secondary battery that can charge electricity and discharge electricity, and more specifically, is a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. For example, the electricity storage element 10 is a medium-sized and large-sized non-aqueous electrolyte secondary battery having a high output and a high capacity of a positive electrode active material coating total area of 0.5 m ² or more.

  As shown in these drawings, the storage element 10 includes a container 100, a positive electrode terminal 200, and a negative electrode terminal 300, and the container 100 includes a lid plate 110 that is an upper wall. In addition, an electrode body 400, a positive electrode current collector 120, and a negative electrode current collector 130 are disposed inside the container 100.

  Note that a liquid such as an electrolytic solution is sealed inside the container 100 of the power storage element 10, but the liquid is not shown. Moreover, the electrical storage element 10 is not limited to a non-aqueous electrolyte secondary battery, and may be a secondary battery other than the non-aqueous electrolyte secondary battery or a capacitor.

  The container 100 includes a casing body having a rectangular cylindrical shape made of metal and having a bottom, and a metal lid plate 110 that closes an opening of the casing body. In addition, the container 100 can be hermetically sealed by welding the lid plate 110 and the housing body after the electrode body 400 and the like are accommodated therein.

  The electrode body 400 includes a positive electrode, a negative electrode, and a separator, and is a member that can store electricity. Specifically, as shown in FIG. 3, the electrode body 400 is wound in a layered manner so that the separator is sandwiched between the negative electrode and the positive electrode so that the whole becomes an oval shape. Is formed. In the drawing, the shape of the electrode body 400 is oval, but it may be circular or elliptical. The shape of the electrode body 400 is not limited to a wound type, and may be a shape in which flat plate plates are stacked. The detailed configuration of the electrode body 400 will be described later.

  The positive electrode terminal 200 is an electrode terminal electrically connected to the positive electrode of the electrode body 400, and the negative electrode terminal 300 is an electrode terminal electrically connected to the negative electrode of the electrode body 400. That is, the positive electrode terminal 200 and the negative electrode terminal 300 lead the electricity stored in the electrode body 400 to the external space of the power storage element 10, and in order to store the electricity in the electrode body 400, It is an electrode terminal made of metal for introducing. The positive electrode terminal 200 and the negative electrode terminal 300 are attached to a lid plate 110 disposed above the electrode body 400.

  The positive electrode current collector 120 is disposed between the positive electrode of the electrode body 400 and the side wall of the container 100, and is a member having conductivity and rigidity that is electrically connected to the positive electrode terminal 200 and the positive electrode of the electrode body 400. It is. The positive electrode current collector 120 is made of aluminum, like the positive electrode of the electrode body 400.

  The negative electrode current collector 130 is disposed between the negative electrode of the electrode body 400 and the side wall of the container 100, and is a member having conductivity and rigidity that is electrically connected to the negative electrode terminal 300 and the negative electrode of the electrode body 400. It is. The negative electrode current collector 130 is made of copper, like the negative electrode of the electrode body 400.

  Various non-aqueous electrolytes (electrolytic solutions) sealed in the container 100 can be selected. For example, as an organic solvent for non-aqueous electrolyte, ethylene carbonate, propylene carbonate, butylene carbonate, trifluoropropylene carbonate, γ-butyrolactone, γ-valerolactone, sulfolane, 1,2-dimethoxyethane, 1,2-diethoxyethane, Tetrahydrofuran, 2-methyltetrahydrofuran, 2-methyl-1,3-dioxolane, dioxolane, fluoroethyl methyl ether, ethylene glycol diacetate, propylene glycol diacetate, ethylene glycol dipropionate, propylene glycol dipropionate, methyl acetate, acetic acid Ethyl, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, dimethyl carbonate, diethyl carbonate, Ethyl methyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, dipropyl carbonate, methyl isopropyl carbonate, ethyl isopropyl carbonate, diisopropyl carbonate, dibutyl carbonate, acetonitrile, fluoroacetonitrile, ethoxypentafluorocyclotriphosphazene, diethoxytetrafluorocyclotriphosphazene, Alkoxy and halogen-substituted cyclic phosphazenes such as phenoxypentafluorocyclotriphosphazene or chain phosphazenes, phosphate esters such as triethyl phosphate, trimethyl phosphate and trioctyl phosphate, boric acids such as triethyl borate and tributyl borate Esters, N-methyloxazolidinone, N-ethyloxazolidinone It includes non-aqueous solvents are. Moreover, a well-known additive can also be added to this. When a solid electrolyte is used, a porous polymer solid electrolyte membrane may be used as the polymer solid electrolyte, and an electrolyte solution may be further contained in the polymer solid electrolyte. Moreover, when using a gel-like polymer solid electrolyte, the electrolyte solution which comprises gel and the electrolyte solution contained in the pore etc. may differ. However, in the case of a medium- or large-sized battery that requires high output and high capacity, it is more preferable to use a non-aqueous electrolyte alone than to use a solid electrolyte or a polymer solid electrolyte.

Moreover, as an electrolyte salt contained in the nonaqueous electrolyte, a known salt containing fluorine can be used without any particular limitation. For example, a salt containing fluorine contained in the electrolyte _salt, LiPF _6, LiBF _4, LiAsF 6, LiSbF ionic compounds such as ₆ and is like a mixture of two or more thereof, electrically stable even in this Therefore, LiPF ₆ having high ionic conductivity is more preferably used in practical use.

  In the electrical storage element 10, these organic solvents and electrolyte salt are combined and used as a nonaqueous electrolyte. Here, it is preferable that the moisture concentration contained in the electricity storage element 10 is 1000 ppm or less, and the moisture concentration is 10 ppm or more. The water concentration is a value obtained by dividing the amount of water contained in the non-aqueous electrolyte by the weight of the electricity storage element 10, that is, the ratio of the total amount of water to the total weight of the electricity storage element 10.

  Next, a detailed configuration of the electrode body 400 will be described.

  FIG. 3 is a cross-sectional view showing the configuration of the electrode assembly 400 according to the embodiment of the present invention. Specifically, FIG. 2 is a view showing a cross section when the portion where the wound state of the electrode body 400 shown in FIG. 2 is developed is cut along the AA cross section.

  As shown in the figure, the electrode body 400 is formed by laminating a positive electrode 410, a negative electrode 420, and two separators 430.

  The positive electrode 410 is obtained by forming a positive electrode active material layer on the surface of a long positive electrode base sheet made of aluminum. In addition, the positive electrode 410 used for the electrical storage element 10 according to the present invention is not particularly different from those conventionally used, and those normally used can be used.

For example, as the positive electrode active material, a known compound can be used without particular limitation, and among them, Li _a Ni _b M1 _c M2 _d W _x Nb _y Zr _z O ₂ (where a, b, c, d, x, y, z are 0 ≦ a ≦ 1.2, 0 ≦ b ≦ 1, 0 ≦ c ≦ 0.5, 0 ≦ d ≦ 0.5, 0 ≦ x ≦ 0.1, 0 ≦ y ≦ 0.1, 0 ≦ z ≦ 0.1, b + c + d = 1, M1 and M2 are selected from the group consisting of Mn, Ti, Cr, Fe, Co, Cu, Zn, Al, Ge, Sn and Mg Which is at least one kind of element).

  The negative electrode 420 is obtained by forming a negative electrode active material layer on the surface of a long strip-shaped negative electrode substrate sheet made of copper. In addition, the negative electrode 420 used for the electrical storage element 10 according to the present invention is not particularly different from that conventionally used, and a commonly used one can be used.

For example, as the negative electrode active material, known compounds can be used without particular limitation. Among them, carbon materials such as hard carbon, soft carbon, and graphite, and transition metal oxides such as TiO ₂ and Li ₄ Ti ₅ O ₁₂ are used. It is preferable to use hard carbon.

  Separator 430 is a long strip separator disposed between positive electrode 410 and negative electrode 420. The separator 430 is wound in the longitudinal direction (Y-axis direction) together with the positive electrode 410 and the negative electrode 420 and laminated in a plurality of layers, whereby the electrode body 400 is formed. The configuration of the separator 430 will be described in detail below.

  FIG. 4 is a cross-sectional view showing a configuration of separator 430 according to the embodiment of the present invention. Specifically, this figure is an enlarged view of the separator 430 shown in FIG.

  As shown in the figure, the separator 430 includes a base material layer 431 and an inorganic filler layer 432.

  The base material layer 431 is a main body of the separator 430, and a general resin porous film can be used. For example, as the base material layer 431, a resin porous film having a woven or non-woven fiber of polymer, natural fiber, hydrocarbon fiber, glass fiber or ceramic fiber is used. The porous resin membrane preferably has woven or non-woven polymer fibers. In particular, the porous resin membrane preferably has a polymer fabric or fleece or is such a fabric or fleece. As polymer fibers, preferably polyacrylonitrile (PAN), polyamide (PA), polyester, such as polyethylene terephthalate (PET) and / or polyolefin (PO), such as polypropylene (PP) or polyethylene (PE) or such polyolefins And non-conductive fibers of a polymer selected from a mixture or composite membrane. The resin porous membrane may be a polyolefin microporous membrane, a nonwoven fabric, paper or the like, and is preferably a polyolefin microporous membrane. In consideration of the influence on the battery characteristics, the thickness of the base material layer 431 is preferably about 5 to 30 μm.

  The inorganic filler layer 432 is a layer disposed on at least one surface of the base material layer 431 and provided on the base material layer 431. That is, the inorganic filler layer 432 is a layer disposed between at least one of the positive electrode 410 and the negative electrode 420 and the separator 430. In the figure, the inorganic filler layer 432 is applied to the upper surface of the base material layer 431, but may be applied to the lower surface or both sides of the base material layer 431. There may be. Further, the inorganic filler layer 432 may be disposed between the positive electrode 410 and the negative electrode 420 without being on the base material layer 431. The inorganic filler layer 432 is preferably provided on the base material layer 431 as shown in FIG. This is because the thermal contraction of the separator can be effectively suppressed.

  Specifically, the inorganic filler layer 432 is a heat-resistant coating layer containing heat-resistant inorganic particles as heat-resistant particles. As the inorganic particles, any of synthetic products and natural products can be used without particular limitation. For example, the inorganic particles include kaolinite, dickite, nacrite, halloysite, audinite, burcherin, amesite, keriaite, fraponite, brindriaite, pyrophyllite, saponite, sauconite, syntholite, montmorillonite, beidellite, nontrotro. Knight, bolcon score, vermiculite, biotite, phlogopite, iron mica, east knight, siderophyllite tetraferri iron mica, scale mica, polyriccionite, muscovite, celadonite, iron ceradonite, iron alumino ceradonite , Alumino ceradon stone, tobe mica, soda mica, clintonite, kinoshita, bite mica, pearl mica, clinochlore, chamosite, penantite, nimite, bailicroa, donbasite, kukeite, sudite And the like.

  The inorganic filler layer 432 is preferably formed by applying a solution in which inorganic particles and a binder are dispersed in a solvent to the base material layer 431. Examples of the binder include polyacrylonitrile, polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, polytetrafluoroethylene, polyhexafluoropropylene, polyethylene oxide, polypropylene oxide, polyphosphazene, polysiloxane, and polyacetic acid. Mention may be made of vinyl, polyvinyl alcohol, polymethyl methacrylate, polyacrylic acid, polymethacrylic acid, styrene-butadiene rubber, nitrile-butadiene rubber, polystyrene or polycarbonate. In particular, the binder used in the present embodiment is preferably polyvinylidene fluoride (PVDF), polyacrylic acid, polymethacrylic acid, or styrene-butadiene rubber. Note that the same binder as described above is used for the binder used in the positive electrode 410 or the negative electrode 420.

  The inorganic particles contained in the inorganic filler layer 432 contain an aluminum silicate compound containing at least one element selected from the group consisting of calcium, sodium, and titanium. The abundance of at least one element selected from the group consisting of calcium, sodium and titanium contained in the inorganic particles (hereinafter referred to as trace elements) is the abundance of all metal elements present in the inorganic particles. It is preferably more than 0.01 at% (atomic percent) and less than 5 at%, more preferably 0.03 to 1 at%.

  Note that the above-described trace elements are contained in the binder, and the inorganic particles and the binder may be mixed together so that the trace elements are contained in the inorganic particles.

  Here, as shown in FIG. 5, the aluminum silicate compound contained in the inorganic particles has a half width of 5 degrees between 2θ of 15 to 25 degrees in X-ray diffraction (XRD) using Cu—Kα rays. An aluminosilicate having the above peaks is preferred. FIG. 5 is a spectrum showing an example of the XRD measurement result of inorganic particles contained in the inorganic filler layer 432 according to the embodiment of the present invention. That is, the aluminum silicate compound is preferably an amorphous compound.

  Next, it will be described in detail that the power storage element 10 having the inorganic filler layer 432 between the positive electrode and the negative electrode can suppress the occurrence of a micro short circuit due to the separation of the inorganic filler layer 432.

[Example]
First, the manufacturing method of the electrical storage element 10 is demonstrated. Specifically, batteries as power storage elements in Examples 1 to 21 and Comparative Examples 1 to 7, which will be described later, were produced as follows. Examples 1 to 21 all relate to power storage element 10 according to the above-described embodiment.

(1-1) Production of positive electrode LiNi _0.16 Mn _0.16 Co _0.67 O ₂ was used as a positive electrode active material. Further, acetylene black was used as the conductive auxiliary agent, PVDF was used as the binder, and the positive electrode active material was blended in an amount of 90% by mass, the conductive auxiliary agent 5% by mass, and the binder 5% by mass. Further, an aluminum foil having a thickness of 20 μm was used as the foil.

(1-2) Production of negative electrode Hard carbon was used as the negative electrode active material. Moreover, PVDF was used for the binder, and it was blended so that the negative electrode active material was 95% by mass and the binder was 5% by mass. Further, a copper foil having a thickness of 15 μm was used as the foil.

(1-3) Production of Separator A polyolefin microporous film having a thickness of 20 μm was used as the base material layer. Moreover, about Examples 1-21 and Comparative Examples 4-7, the inorganic particle and binder containing said aluminum silicate compound were mixed so that mass ratio might be set to 97: 3 in a solvent, and coating agent Was made. Moreover, about Comparative Examples 1-3, it replaced with said aluminum silicate compound, the mixture of an alumina and a silica, the inorganic particle and binder which each contained an alumina and a silica, and mass ratio were 97: 3 in a solvent. The coating agent was prepared by mixing so that

  In addition, the average particle diameter D50 of the said inorganic particle was 2 micrometers, and it adjusted so that the below-mentioned trace element might be contained in the aluminum silicate compound, the mixture of an alumina and a silica, an alumina, and a silica. An acrylic resin was used for the binder.

  And the inorganic coating separator provided with the inorganic filler layer of thickness 5micrometer was produced by carrying out the gravure coat of the said coating agent on a base material layer, and making it dry at 80 degreeC for 12 hours.

(1-4) Generation of non-aqueous electrolyte For the non-aqueous electrolyte, a mixed solvent of propylene carbonate (PC): dimethyl carbonate (DMC): ethyl methyl carbonate (EMC) = 3: 2: 5 (volume ratio) was used. For Examples 1-21 and Comparative Examples 1-3, 5-7, LiPF ₆ was added, and for Comparative Example 4, LiClO ₄ was added at 1 mol / l. In addition, 0.02 mol / l of diethyl sulfate and 0.005 mol / l of tris (trimethylsilyl) phosphate were added as additives, and the water content was adjusted so that the water concentration was a value described later.

(1-5) Production of Battery The positive electrode, the negative electrode, and the separator were laminated so that the inorganic filler layer of the separator faced the positive electrode, wound, and then inserted into a container, and a nonaqueous electrolyte was injected and sealed.

  Next, a battery evaluation test was performed as follows.

(2-1) Measurement of moisture concentration The battery was disassembled, and the moisture content of the positive electrode active material layer, the negative electrode active material layer, the separator, and other water-containing members was measured with a Karl Fischer moisture meter and included in the battery. The amount of water contained was defined as the amount of water in the battery. And the value which remove | divided the said water | moisture content in the said battery by the battery weight was made into the moisture concentration.

(2-2) Micro short-circuit confirmation test When the battery is charged to 20% of the rated battery capacity and stored at 25 ° C. for 20 days, the difference between the battery voltage before storage and the battery voltage after storage (battery voltage) The ratio (%) of the batteries in which the decrease was 0.1 V or more was defined as the minute short-circuit occurrence rate. In this example, after performing constant voltage charging of 3.1 V for 3 hours, voltage measurement was performed within 12 hours, and after 20 days storage at 25 ° C., voltage measurement was performed again, and the difference was reduced to the battery voltage. It was. And the test of 50 cells per 1 level was done, the said ratio was calculated, and it was set as the micro short circuit occurrence rate.

  The following Tables 1 to 5 show the moisture concentration and the micro short-circuit occurrence rate of the battery obtained as described above. That is, in the following Tables 1 to 5, with respect to Examples 1 to 21 and Comparative Examples 1 to 7, the type of substances contained in the inorganic particles, the amount of trace elements, the salt contained in the electrolyte salt, the moisture concentration, and the trace elements This compares the incidence of micro short-circuits in the battery when the type of the battery is changed.

  First, Example 1 and Comparative Examples 1 to 3 will be described using Table 1 below. As shown in Table 1 below, Example 1 and Comparative Examples 1 to 3 are the types of substances contained in inorganic particles by fixing the kind of trace elements, the amount of trace elements, the salt contained in the electrolyte salt, and the moisture concentration. It shows the micro short-circuit occurrence rate of the battery when the type is changed. Note that “trace Ca” in Table 1 indicates that calcium is contained as a trace element. The same applies to Tables 2 to 4 below.

  As shown in Table 1, when the inorganic particles contain an aluminum silicate compound, the occurrence rate of minute short-circuiting of the battery can be suppressed.

  Next, Examples 1 to 8 will be described using Table 2 below. As shown in Table 2 below, in Examples 1 to 8, the types of substances contained in the inorganic particles, the types of trace elements, the salts contained in the electrolyte salt, the moisture concentration are fixed, and the amounts of the trace elements are changed. It shows the micro short-circuit occurrence rate of the battery in the case of.

  As shown in Table 2, when the amount of the trace element is 0.03 to 1 at%, the micro short-circuit occurrence rate of the battery can be suppressed. Similarly, the inventors of the present application have found that when the total amount of trace elements is more than 0.01 at% and less than 5 at%, the occurrence rate of minute short-circuiting of the battery can be effectively suppressed. It was.

  Next, Example 1 and Comparative Example 4 will be described using Table 3 below. As shown in Table 3 below, in Example 1 and Comparative Example 4, the types of substances contained in the inorganic particles, the types of trace elements, the amounts of trace elements, the water concentration are fixed, and the salts contained in the electrolyte salt are changed. It shows the micro short-circuit occurrence rate of the battery when it is changed.

As shown in Table 3, when the salt contained in the electrolyte salt is a salt containing fluorine, particularly when the salt is LiPF ₆ , the occurrence rate of micro short-circuiting of the battery can be suppressed. .

  Next, Examples 1 and 9 to 16 and Comparative Examples 5 to 7 will be described using Table 4 below. As shown in Table 4 below, Examples 1, 9-16 and Comparative Examples 5-7 show the types of substances contained in inorganic particles, the types of trace elements, the amounts of trace elements, and the salts contained in electrolyte salts. It shows the rate of micro short-circuit occurrence of the battery when the moisture concentration is fixed.

  As shown in Table 4, when the moisture concentration is 1000 ppm or less, and when the moisture concentration is 10 ppm or more, the occurrence rate of minute short-circuiting of the battery can be suppressed. In addition, the water concentration which exists in the electrical storage element using a nonaqueous electrolyte is 1000 ppm or less normally.

  Next, Examples 1 and 17 to 21 will be described using Table 5 below. As shown in Table 5 below, in Examples 1 and 17 to 21, the types of substances contained in the inorganic particles, the amounts of trace elements, the salts contained in the electrolyte salt, the moisture concentration are fixed, and the types of trace elements are changed. It shows the micro short-circuit occurrence rate of the battery when it is changed. “Trace elements (0.1 at%)” in Table 5 indicate that the aluminum silicate compound contains 0.1 at% trace elements (calcium, sodium, titanium).

  As shown in Table 5, when the trace element is at least one element selected from the group consisting of calcium, sodium and titanium, the occurrence rate of micro short-circuits in the battery can be suppressed.

  As described above, according to the energy storage device 10 according to the embodiment of the present invention, the inorganic filler layer 432 that is an inorganic layer including inorganic particles is disposed between the positive electrode 410 and the negative electrode 420, and the inorganic particles are In addition, the electrolyte salt included in the non-aqueous electrolyte includes an aluminum silicate compound including at least one element selected from the group consisting of calcium, sodium, and titanium. The concentration is 1000 ppm or less. Here, as a result of intensive studies and experiments, the inventors of the present application have found that the occurrence of a minute short circuit can be suppressed in the configuration of the power storage device 10 described above. The following reasons can be considered as the mechanism. When the electrolyte salt contains a salt containing fluorine and the water concentration in the electricity storage device 10 is 1000 ppm or less, a trace amount of hydrogen fluoride (HF) is generated in the electricity storage device 10 to constitute an aluminum silicate compound. Silica dissolves in the HF. And the said silica reacts with the at least 1 sort (s) of element chosen from the group which consists of calcium, sodium, and titanium contained in an aluminum silicate compound, and a part of inorganic layers are bound together by recrystallization. The separation of the inorganic filler layer 432 is suppressed. Accordingly, in the power storage device 10 having the inorganic filler layer 432 between at least one of the positive electrode 410 and the negative electrode 420 and the separator 430, the yield is improved by suppressing the occurrence of a micro short circuit due to the separation of the inorganic filler layer 432. be able to. Further, by suppressing the occurrence of a minute short circuit due to the separation of the inorganic filler layer 432, the capacity retention rate of the power storage element 10 can be improved.

  Further, as a result of intensive studies and experiments, the present inventors have found that the abundance of at least one element selected from the group consisting of calcium, sodium and titanium contained in the inorganic particles is all the metals present in the inorganic particles. It has been found that the occurrence of micro short-circuits can be effectively suppressed when the amount is greater than 0.01 at% and less than 5 at% with respect to the element abundance. For this reason, in the electrical storage element 10 having the inorganic filler layer 432 between at least one of the positive electrode 410 and the negative electrode 420 and the separator 430, generation of a micro short circuit due to separation of the inorganic filler layer 432 is suppressed and yield is improved. be able to.

  Further, as a result of intensive studies and experiments, the inventors of the present application have found that the occurrence of a micro short circuit can be suppressed when the moisture concentration in the electric storage element 10 is 10 ppm or more. For this reason, in the electrical storage element 10 having the inorganic filler layer 432 between at least one of the positive electrode 410 and the negative electrode 420 and the separator 430, generation of a micro short circuit due to separation of the inorganic filler layer 432 is suppressed and yield is improved. be able to.

  In the power storage element 10, since the inorganic filler layer 432 is provided on the base material layer 431 of the separator 430, the inorganic filler layer 432 can be disposed between the positive electrode 410 and the negative electrode 420 with a simple configuration.

  Note that the present invention can be realized not only as such a power storage element 10 but also as a separator 430 included in the power storage element 10.

  The power storage element 10 according to the embodiment of the present invention has been described above, but the present invention is not limited to this embodiment.

  That is, the embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  INDUSTRIAL APPLICABILITY The present invention can be applied to a power storage element having an inorganic layer between a positive electrode and a negative electrode and capable of improving safety by suppressing the occurrence of a micro short circuit due to the separation of the inorganic layer.

DESCRIPTION OF SYMBOLS 10 Power storage element 100 Container 110 Cover plate 120 Positive electrode current collector 130 Negative electrode current collector 200 Positive electrode terminal 300 Negative electrode terminal 400 Electrode body 410 Positive electrode 420 Negative electrode 430 Separator 431 Base material layer 432 Inorganic filler layer

Claims (3)

A storage element comprising a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and a nonaqueous electrolyte containing an electrolyte salt,
An inorganic filler layer containing inorganic particles is disposed between at least one of the positive electrode and the negative electrode and the separator,
The inorganic particles comprise an aluminum silicate compound containing at least one element selected from the group consisting of calcium, sodium and titanium,
The electrolyte salt, only contains a salt containing fluorine,
The abundance of at least one element selected from the group consisting of calcium, sodium and titanium contained in the inorganic particles is more than 0.01 at% with respect to the abundance of all the metal elements present in the inorganic particles. Less than 5at%,
The electrical storage element whose water concentration in the said electrical storage element defined by the moisture content with respect to the weight of the said electrical storage element is 10 ppm or more and 1000 ppm or less . The inorganic filler layer, electric storage device according to claim 1 provided in the separator. Said salt having the fluorine contained in the electrolyte salt, the electric storage device according to claim 1 or 2 which is LiPF _6.

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