JP5076280B2 - Non-aqueous secondary battery electrolyte and non-aqueous secondary battery - Google Patents

Description

The present invention relates to a nonaqueous secondary battery using the electrolyte and for a non-aqueous secondary battery comprising a fluoride carbonate.

  In recent years, many portable electronic devices such as a camera-integrated VTR (video tape recorder), a digital still camera, a mobile phone, a portable information terminal, or a notebook computer have appeared, and their weight and size have been reduced. Accordingly, as a portable power source for electronic devices, research and development for improving the energy density of batteries, particularly secondary batteries, are being actively promoted. Among these, lithium ion secondary batteries using a carbon material for the negative electrode, a composite material of lithium and a transition metal for the positive electrode, and a carbonate ester for the electrolytic solution are larger than conventional lead batteries and nickel cadmium batteries. Since energy density can be obtained, it is widely used.

In recent years, with the improvement in performance of portable electronic devices, further improvement in capacity has been demanded, and tin (Sn) or silicon (Si) or the like can be used as a negative electrode active material instead of a carbon material. (For example, refer patent document 1). This is because the theoretical capacity of tin is 994 mAh / g and the theoretical capacity of silicon is 4199 mAh / g, which is much larger than the theoretical capacity of graphite, 372 mAh / g, and an improvement in capacity can be expected.
U.S. Pat. No. 4,950,566

  However, since tin alloys or silicon alloys that occlude lithium (Li) are highly active, the use of carbonates or the like that have been used in the electrolyte solution will cause them to be decomposed, and lithium is inactivated. There was a problem that. Therefore, it has been studied to use a carbonate ester fluoride in the electrolytic solution to suppress a decrease in charge and discharge efficiency and improve cycle characteristics. However, although the cycle characteristics can be improved by this, the deterioration of the characteristics after high temperature storage is still large, and it has been desired to improve the high temperature storage characteristics.

This invention is made | formed in view of this problem, The objective is to provide the electrolyte solution for non-aqueous secondary batteries which can improve a high temperature storage characteristic, and a non-aqueous secondary battery.

Non-aqueous liquid electrolyte for a secondary battery according to the present invention includes a fluoride charcoal ester, an electrolyte for non-aqueous secondary battery comprising a solvent containing a chloride of carbonic acid ester, carbonic acid ester in the electrolytic solution The content of the chloride in the range of 5 ppm to 8000 ppm by mass, and the content of the carbonate ester fluoride in the solvent is in the range of 20% to 70% by mass.

A non-aqueous secondary battery according to the present invention is provided with an electrolyte solution together with a positive electrode and a negative electrode, and the electrolyte solution contains a carbonate ester fluoride and a carbonate ester chloride as a solvent. the content of chloride of carbonic esters in the Ri range der 5 mass ppm or 8000 ppm by mass or less), the content of fluoride carbonate in the solvent is 20 wt% to 70 wt% within the range of belongs to.

According to the electrolyte for a non-aqueous secondary battery of the present invention, since it contains carbonate fluoride and a small amount of carbonate chloride, chemical stability can be improved even at high temperatures. it can. Therefore, if it uses for the non-aqueous secondary battery of this invention using this electrolyte solution for non-aqueous secondary batteries, battery characteristics, such as a high temperature storage characteristic, can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  The electrolytic solution according to an embodiment of the present invention includes, for example, a solvent and an electrolyte salt dissolved in the solvent.

  The solvent contains a carbonate ester fluoride and a carbonate ester chloride. Among these, the content of carbonate ester chloride in the electrolyte solution is in the range of 5 ppm to 8000 ppm by mass, and more preferably in the range of 30 ppm to 5000 ppm by mass. Thereby, reduction resistance can be improved not only at normal temperature but also at high temperature, and decomposition of the electrolytic solution can be suppressed even at high temperature.

  As the fluoride of carbonate ester, a fluoride of cyclic carbonate ester is preferable, and for example, one having 1,3-dioxolan-2-one shown in Chemical Formula 1 as a basic skeleton is preferable. Examples of such a compound include 4-fluoro-1,3-dioxolan-2-one, 4,4-difluoro-1,3-dioxolan-2-one, and 4,5-difluoro-1,3-dioxolane. -2-one, 4,4,5-trifluoro-1,3-dioxolan-2-one, 4,4,5,5-tetrafluoro-1,3-dioxolan-2-one, 4-fluoromethyl- 1,3-dioxolan-2-one, 4-difluoromethyl-1,3-dioxolan-2-one, or 4-trifluoromethyl-1,3-dioxolan-2-one, among which The indicated 4-fluoro-1,3-dioxolan-2-one is preferred. This is because a higher effect can be obtained. Carbonate ester fluorides may be used alone or in combination of two or more.

  As the carbonate of the carbonate ester, a chloride of the cyclic carbonate ester is preferable. Like the fluoride, the one having 1,3-dioxolan-2-one shown in Chemical Formula 1 as a basic skeleton is preferable. Examples of such include 4-chloro-1,3-dioxolan-2-one, 4,4-dichloro-1,3-dioxolan-2-one, and 4,5-dichloro-1,3-dioxolane. -2-one, 4,4,5-trichloro-1,3-dioxolan-2-one, 4,4,5,5-tetrachloro-1,3-dioxolan-2-one, 4-chloromethyl-1 , 3-dioxolan-2-one, 4-dichloromethyl-1,3-dioxolan-2-one, or 4-trichloromethyl-1,3-dioxolan-2-one, among which 4-Chloro-1,3-dioxolan-2-one is preferred. This is because a higher effect can be obtained. Carbonate ester chlorides may be used alone or in combination of two or more.

  In addition, although a solvent may be comprised with the fluoride and chloride of carbonate ester, you may mix and use another 1 type, or 2 or more types of solvent. This is because various properties such as ion conductivity can be improved.

  Other solvents include, for example, cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate, or 1,3-dioxol-2-one, lactones such as γ-butyrolactone or γ-valerolactone, 2-methyl- Lactams such as 1-pyrrolidone, cyclic carbamates such as 3-methyl-2-oxazolidinone, cyclic sulfones such as tetramethylene sulfone, chain carbonates such as diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, or methylpropyl carbonate Ester, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, methyl isobutyrate, methyl trimethylacetate, etc., ketones such as pinacholine, 1,2-dimethoxyethane, tetrahydrofuran, tetrahydropyran, 1 , Ethers such as 3-dioxolane, 1,3-dioxane, or 1,4-dioxane, chain amides such as N, N-dimethylformamide, N, N-dimethylacetamide, or methyl N, N-dimethylcarbamate, And chain carbamates such as methyl N, N-diethylcarbamate.

  Especially, when using the cyclic compound mentioned above as the fluoride and chloride of carbonate, it is preferable to mix with the low viscosity solvent whose viscosity is 1 mPa * s or less. This is because the cyclic carbonate is a high dielectric constant solvent having a relative dielectric constant of 30 or more, so that ion conductivity can be further improved by mixing with one or more low viscosity solvents. Examples of the low-viscosity solvent include a chain carbonate ester, a chain carboxylate ester, a ketone, an ether, a chain amide, or a chain carbamate ester among the solvents described above.

Examples of the electrolyte salt include lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium hexafluoroarsenate (LiAsF ₆ ), lithium perchlorate (LiClO ₄ ), trifluoro. Lithium perfluoroalkanesulfonates such as lithium methanesulfonate (LiCF ₃ SO ₃ ), lithium bis (trifluoromethanesulfonyl) imide (LiN (CF ₃ SO ₂ ) ₂ ), lithium bis (pentafluoroethanesulfonyl) imide (LiN ( Lithium salts such as C ₂ F ₅ SO ₂ ) ₂ ), lithium tris (trifluoromethanesulfonyl) methide (LiC (CF ₃ SO ₂ ) ₃ ), or lithium bisoxalate borate (LiB (C ₂ O ₄ ) ₂ ) Can be mentioned. Any one electrolyte salt may be used alone, or two or more electrolyte salts may be mixed and used.

  This electrolytic solution is used for a secondary battery as follows, for example.

(First secondary battery)
FIG. 1 shows a cross-sectional configuration of a first secondary battery using the electrolytic solution according to the present embodiment. This secondary battery is a so-called lithium ion secondary battery in which the capacity of the negative electrode is represented by a capacity component due to insertion and extraction of lithium as an electrode reactant. This secondary battery is a so-called cylindrical type, and a wound electrode body 20 in which a belt-like positive electrode 21 and a negative electrode 22 are wound through a separator 23 inside a substantially hollow cylindrical battery can 11. have. The battery can 11 is made of, for example, iron (Fe) plated with nickel (Ni), and has one end closed and the other end open. Inside the battery can 11, a pair of insulating plates 12, 13 are arranged perpendicular to the winding peripheral surface so as to sandwich the winding electrode body 20.

  At the open end of the battery can 11, a battery lid 14, a safety valve mechanism 15 provided inside the battery lid 14 and a heat sensitive resistance element (Positive Temperature Coefficient; PTC element) 16 are interposed via a gasket 17. It is attached by caulking, and the inside of the battery can 11 is sealed. The battery lid 14 is made of, for example, the same material as the battery can 11. The safety valve mechanism 15 is electrically connected to the battery lid 14 via the heat sensitive resistance element 16, and the disk plate 15A is reversed when the internal pressure of the battery exceeds a certain level due to an internal short circuit or external heating. Thus, the electrical connection between the battery lid 14 and the wound electrode body 20 is cut off. When the temperature rises, the heat sensitive resistance element 16 limits the current by increasing the resistance value and prevents abnormal heat generation due to a large current. The gasket 17 is made of, for example, an insulating material, and asphalt is applied to the surface.

  For example, a center pin 24 is inserted in the center of the wound electrode body 20. A positive electrode lead 25 made of aluminum (Al) or the like is connected to the positive electrode 21 of the spirally wound electrode body 20, and a negative electrode lead 26 made of nickel or the like is connected to the negative electrode 22. The positive electrode lead 25 is electrically connected to the battery lid 14 by being welded to the safety valve mechanism 15, and the negative electrode lead 26 is welded to and electrically connected to the battery can 11.

  FIG. 2 shows an enlarged part of the spirally wound electrode body 20 shown in FIG. The positive electrode 21 has, for example, a structure in which a positive electrode active material layer 21B is provided on both surfaces of a positive electrode current collector 21A having a pair of opposed surfaces. The positive electrode current collector 21A is made of, for example, a metal foil such as an aluminum foil, a nickel foil, or a stainless steel foil.

The positive electrode active material layer 21B includes, for example, one or more of positive electrode materials capable of inserting and extracting lithium as a positive electrode active material, and a conductive material such as a carbon material and polyfluoride as necessary. A binder such as vinylidene may be included. The positive electrode material capable of inserting and extracting lithium does not contain lithium such as titanium sulfide (TiS ₂ ), molybdenum sulfide (MoS ₂ ), niobium selenide (NbSe ₂ ), or vanadium oxide (V ₂ O ₅ ). Examples include chalcogenides and lithium-containing compounds containing lithium.

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, or a phosphate compound containing lithium and a transition metal element. In particular, cobalt (Co), nickel and manganese (Mn Among these, those containing at least one of them are preferred. This is because a higher voltage can be obtained. The chemical formula is represented by, for example, Li _x MIO ₂ or Li _y MIIPO ₄ . In the formula, MI and MII represent one or more transition metal elements. The values of x and y vary depending on the charge / discharge state of the battery, and are generally 0.05 ≦ x ≦ 1.10 and 0.05 ≦ y ≦ 1.10.

Specific examples of the composite oxide containing lithium and a transition metal element include lithium cobalt composite oxide (Li _x CoO ₂ ), lithium nickel composite oxide (Li _x NiO ₂ ), and lithium nickel cobalt composite oxide (Li _x Ni _1-z Co _z O ₂ (z <1)), lithium nickel cobalt manganese composite oxide (Li _x Ni _1-vw Co _v Mn _w O ₂ (v + w <1)), or lithium manganese having a spinel structure Examples include composite oxide (LiMn ₂ O ₄ ). Among these, a composite oxide containing nickel is preferable. This is because a high capacity can be obtained and excellent cycle characteristics can also be obtained. Specific examples of the phosphate compound containing lithium and a transition metal element include, for example, a lithium iron phosphate compound (LiFePO ₄ ) or a lithium iron manganese phosphate compound (LiFe _1-u Mn _u PO ₄ (u <1)). Can be mentioned.

  The negative electrode 22 has, for example, a structure in which a negative electrode active material layer 22B is provided on both surfaces of a negative electrode current collector 22A having a pair of opposed surfaces. The negative electrode current collector 22A is made of, for example, a metal foil such as a copper (Cu) foil, a nickel foil, or a stainless steel foil.

  The negative electrode active material layer 22B includes, for example, any one or more of negative electrode materials capable of inserting and extracting lithium as a negative electrode active material. Examples of the negative electrode material capable of inserting and extracting lithium include a material containing tin or silicon as a constituent element. This is because tin and silicon have a large ability to occlude and release lithium, and a high energy density can be obtained.

  As such a negative electrode material, specifically, a simple substance, an alloy, or a compound of tin, a simple substance, an alloy, or a compound of silicon, or a material having one or more phases thereof at least in part. Is mentioned. In the present invention, alloys include those containing one or more metal elements and one or more metalloid elements in addition to those composed of two or more metal elements. Moreover, the nonmetallic element may be included. There are structures in which a solid solution, a eutectic (eutectic mixture), an intermetallic compound, or two or more of them coexist.

  As an alloy of tin, for example, as a second constituent element other than tin, silicon, nickel, copper, iron, cobalt, manganese, zinc (Zn), indium (In), silver (Ag), titanium (Ti), Examples include those containing at least one selected from the group consisting of germanium (Ge), bismuth (Bi), antimony (Sb), and chromium (Cr). As an alloy of silicon, for example, as a second constituent element other than silicon, among the group consisting of tin, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony and chromium The thing containing at least 1 sort (s) of these 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.

  Among these, as this negative electrode material, tin, cobalt, and carbon are included as constituent elements, the carbon content is 9.9 mass% or more and 29.7 mass% or less, and the total of tin and cobalt is A CoSnC-containing material having a cobalt ratio Co / (Sn + Co) of 30% by mass to 70% by mass is preferable. This is because a high energy density can be obtained in such a composition range, and excellent cycle characteristics can be obtained.

  This CoSnC-containing material may further contain other constituent elements as necessary. As other constituent elements, for example, silicon, iron, nickel, chromium, indium, niobium (Nb), germanium, titanium, molybdenum (Mo), aluminum, phosphorus (P), gallium (Ga) or bismuth is preferable. It may contain more than seeds. This is because the capacity or cycle characteristics can be further improved.

  This CoSnC-containing material has a phase containing tin, cobalt, and carbon, and this phase preferably has a low crystallinity or an amorphous structure. In this CoSnC-containing material, it is preferable that at least a part of carbon as a constituent element is bonded to a metal element or a semimetal element as another constituent element. The decrease in cycle characteristics is thought to be due to the aggregation or crystallization of tin or the like, but this is because such aggregation or crystallization can be suppressed by combining carbon with other elements. .

  As a measuring method for examining the bonding state of elements, for example, X-ray photoelectron spectroscopy (XPS) can be cited. In XPS, the peak of the carbon 1s orbital (C1s) appears at 284.5 eV in an energy calibrated apparatus so that the peak of the gold atom 4f orbital (Au4f) is obtained at 84.0 eV if it is graphite. . Moreover, if it is surface contamination carbon, it will appear at 284.8 eV. On the other hand, when the charge density of the carbon element increases, for example, when carbon is bonded to a metal element or a metalloid element, the C1s peak appears in a region lower than 284.5 eV. That is, when the peak of the synthetic wave of C1s obtained for the CoSnC-containing material appears in a region lower than 284.5 eV, at least a part of the carbon contained in the CoSnC-containing material is a metal element or a half of other constituent elements. Combined with metal elements.

  In XPS measurement, for example, the C1s peak is used to correct the energy axis of the spectrum. Usually, since surface-contaminated carbon exists on the surface, the C1s peak of the surface-contaminated carbon is set to 284.8 eV, which is used as an energy standard. In the XPS measurement, the waveform of the C1s peak is obtained as a shape including the surface contamination carbon peak and the carbon peak in the CoSnC-containing material. For example, by analyzing using a commercially available software, the surface contamination The carbon peak and the carbon peak in the CoSnC-containing material are separated. In the waveform analysis, the position of the main peak existing on the lowest bound energy side is used as the energy reference (284.8 eV).

  As a negative electrode material capable of inserting and extracting lithium, for example, a material containing another metal element or other metalloid element capable of forming an alloy with lithium as a constituent element can also be used. Such metal elements or metalloid elements include magnesium (Mg), boron (B), aluminum, gallium, indium, germanium, lead (Pb), bismuth, cadmium (Cd), silver, zinc, hafnium (Hf). , Zirconium (Zr), yttrium (Y), palladium (Pd), or platinum (Pt).

  As a negative electrode material capable of inserting and extracting lithium, for example, a carbon material such as graphite, non-graphitizable carbon, or graphitizable carbon may be used. The negative electrode material may be used together. The carbon material has very little change in crystal structure due to insertion and extraction of lithium. For example, when used together with the negative electrode material described above, a high energy density and excellent cycle characteristics can be obtained. It is also preferable because it functions as a conductive agent.

  The negative electrode active material layer 22B may also include other materials that do not contribute to charging, such as a conductive agent, a binder, or a viscosity modifier. Examples of the conductive agent include graphite fiber, metal fiber, and metal powder. Examples of the binder include a fluorine-based polymer compound such as polyvinylidene fluoride, or a synthetic rubber such as styrene butadiene rubber or ethylene propylene diene rubber. Examples of the viscosity modifier include carboxymethylcellulose.

Note that in this embodiment, by adjusting the amount of the positive electrode active material and the negative electrode material capable of inserting and extracting lithium, lithium can be stored and released rather than the charge capacity of the positive electrode active material. possible as towards the charge capacity due to the anode material increases, lithium metal is not a precipitated on the anode 22 even at the time of full charge.

  The separator 23 separates the positive electrode 21 and the negative electrode 22 and allows lithium ions to pass through while preventing a short circuit of current due to contact between the two electrodes. The separator 23 is made of, for example, a porous film made of synthetic resin made of polytetrafluoroethylene, polypropylene, polyethylene or the like, or a multi-hard film made of ceramic, and these two or more kinds of porous films are laminated. It may be made the structure.

  The separator 23 is impregnated with the electrolytic solution according to the present embodiment.

  For example, the secondary battery can be manufactured as follows.

  First, for example, the positive electrode active material layer 21B is formed on the positive electrode current collector 21A to produce the positive electrode 21. The positive electrode active material layer 21B is prepared, for example, by mixing a positive electrode active material powder, a conductive agent, and a binder to prepare a positive electrode mixture, and then using the positive electrode mixture in a solvent such as N-methyl-2-pyrrolidone. The positive electrode mixture slurry is dispersed to form a positive electrode mixture slurry, and the positive electrode mixture slurry is applied to the positive electrode current collector 21A, dried, and compression molded. Further, for example, in the same manner as the positive electrode 21, the negative electrode active material layer 22 </ b> B is formed on the negative electrode current collector 22 </ b> A to produce the negative electrode 22.

  Next, the positive electrode lead 25 is attached to the positive electrode current collector 21A by welding or the like, and the negative electrode lead 26 is attached to the negative electrode current collector 22A by welding or the like. Subsequently, the positive electrode 21 and the negative electrode 22 are wound through the separator 23, and the tip of the positive electrode lead 25 is welded to the safety valve mechanism 15, and the tip of the negative electrode lead 26 is welded to the battery can 11. The positive electrode 21 and the negative electrode 22 are sandwiched between a pair of insulating plates 12 and 13 and stored in the battery can 11. After the positive electrode 21 and the negative electrode 22 are accommodated in the battery can 11, the electrolytic solution is injected into the battery can 11 and impregnated in the separator 23. After that, the battery lid 14, the safety valve mechanism 15, and the heat sensitive resistance element 16 are fixed to the opening end of the battery can 11 by caulking through a gasket 17. Thereby, the secondary battery shown in FIGS. 1 and 2 is completed.

  In the secondary battery, when charged, for example, lithium ions are extracted from the positive electrode 21 and inserted in the negative electrode 22 through the electrolytic solution. On the other hand, when discharging is performed, for example, lithium ions are extracted from the negative electrode 22 and inserted in the positive electrode 21 through the electrolytic solution. At that time, since the electrolyte solution contains a carbonate ester fluoride and a small amount of carbonate chloride, the decomposition reaction of the electrolyte solution is suppressed even at high temperatures.

  As described above, according to the present embodiment, since the electrolyte solution contains the carbonate ester fluoride and a small amount of carbonate chloride, the chemical stability at high temperature can be improved, Storage characteristics can be improved.

(Secondary secondary battery)
The second secondary battery has the same configuration and operation as the first secondary battery except that the configuration of the negative electrode is different, and can be manufactured in the same manner. Therefore, with reference to FIG. 1 and FIG. 2, the same code | symbol is attached | subjected to a corresponding component and description of the same part is abbreviate | omitted.

  Similar to the first secondary battery, the negative electrode 22 has a structure in which a negative electrode active material layer 22B is provided on both surfaces of a negative electrode current collector 22A. The negative electrode active material layer 22B contains, for example, a negative electrode active material containing tin or silicon as a constituent element. Specifically, for example, it contains a simple substance, an alloy, or a compound of tin, or a simple substance, an alloy, or a compound of silicon, and may contain two or more of them.

  The negative electrode active material layer 22B is formed using, for example, a vapor phase method, a liquid phase method, a firing method, or two or more of these methods. The negative electrode active material layer 22B and the negative electrode current collector 22A are formed. Are preferably alloyed in at least part of the interface. Specifically, it is preferable that the constituent element of the negative electrode current collector 22A is diffused in the negative electrode active material layer 22B, the constituent element of the negative electrode active material is diffused in the negative electrode current collector 22A, or they are mutually diffused at the interface. This is because breakage due to expansion / contraction of the negative electrode active material layer 22B due to charging / discharging can be suppressed, and electronic conductivity between the negative electrode active material layer 22B and the negative electrode current collector 22A can be improved. .

As the vapor phase method, for example, a physical deposition method or a chemical deposition method can be used. Specifically, a vacuum deposition method, a sputtering method, an ion plating method, a laser ablation method, a thermal chemical vapor deposition ( Examples include CVD (Chemical Vapor Deposition), plasma chemical vapor deposition, and thermal spraying. As the liquid phase method, a known method such as electroplating or electroless plating can be used. The firing method is, for example, a method in which a particulate negative electrode active material is mixed with a binder, dispersed in a solvent, applied, and then heat-treated at a temperature higher than the melting point of the binder. For firing method, a known technique are available, for example, an atmosphere firing method, have in reactive firing method include hot-press firing method.

(Third secondary battery)
The third secondary battery is a so-called lithium metal secondary battery in which the capacity of the negative electrode 22 is represented by a capacity component due to precipitation and dissolution of lithium as an electrode reactant. This secondary battery has the same configuration as the first secondary battery except that the negative electrode active material layer 22B is made of lithium metal, and can be manufactured in the same manner. Therefore, with reference to FIG. 1 and FIG. 2, the same code | symbol is attached | subjected to a corresponding component and description of the same part is abbreviate | omitted.

  That is, this secondary battery uses lithium metal as a negative electrode active material, and thereby can obtain a high energy density. The negative electrode active material layer 22B may be configured to be already provided from the time of assembly, but may be configured by lithium metal which is not present at the time of assembly and is deposited during charging. Alternatively, the negative electrode active material layer 22B may be used as a current collector, and the negative electrode current collector 22A may be deleted.

  In the secondary battery, when charged, for example, lithium ions are extracted from the positive electrode 21 and deposited as lithium metal on the surface of the negative electrode current collector 22A through the electrolytic solution. When the discharge is performed, for example, lithium metal is eluted as lithium ions from the negative electrode active material layer 22B, and is occluded in the positive electrode 21 through the electrolytic solution. As described above, in this secondary battery, the deposition and dissolution of lithium metal are repeated in the negative electrode 22, so that the activity of the negative electrode 22 is very high. However, in this embodiment, the electrolyte is highly chemical even at high temperatures. Since it has stability, excellent high-temperature storage characteristics can be obtained.

(Fourth secondary battery)
In the fourth secondary battery, the capacity of the negative electrode includes a capacity component due to insertion and extraction of lithium as an electrode reactant, and a capacity component due to precipitation and dissolution of lithium, and is represented by the sum thereof. This secondary battery has the same configuration as that of the first secondary battery except that the configuration of the negative electrode active material layer 22B is different, and can be manufactured in the same manner. Therefore, with reference to FIG. 1 and FIG. 2, the same code | symbol is attached | subjected to a corresponding component and description of the same part is abbreviate | omitted.

  The negative electrode active material layer 22B includes one or more negative electrode materials capable of inserting and extracting lithium as a negative electrode active material, and may include a binder as necessary. As such a negative electrode material, for example, a carbon material described in the first secondary battery, or a material containing a metal element or a metalloid element capable of forming an alloy with lithium as a constituent element can be given. Among these, it is preferable to use a carbon material because excellent cycle characteristics can be obtained.

  The amount of the negative electrode material capable of inserting and extracting lithium is adjusted so that the charge capacity of the negative electrode material is smaller than the charge capacity of the positive electrode 21. As a result, in the secondary battery, lithium metal starts to deposit on the negative electrode 22 at the time when the open circuit voltage (that is, the battery voltage) is lower than the overcharge voltage in the charging process.

  The overcharge voltage refers to the open circuit voltage when the battery is overcharged. For example, the “lithium secondary battery” is one of the guidelines established by the Japan Storage Battery Industry Association (Battery Industry Association). Refers to a voltage that is higher than the open circuit voltage of a “fully charged” battery as defined and defined in the “Safety Evaluation Criteria Guidelines” (SBA G1101). In other words, it refers to a voltage higher than the open circuit voltage after charging using the charging method, standard charging method, or recommended charging method used when determining the nominal capacity of each battery. For example, when full charge occurs when the open circuit voltage is 4.2 V, lithium metal is formed on the surface of the negative electrode material capable of inserting and extracting lithium in a part of the open circuit voltage in the range of 0 V to 4.2 V. Is deposited. Therefore, in this secondary battery, both the negative electrode material capable of occluding and releasing lithium and lithium metal function as the negative electrode active material, and the negative electrode material capable of occluding and releasing lithium is a base material on which the lithium metal is deposited. It has become. Thereby, in this secondary battery, the characteristics of both a so-called lithium ion secondary battery and a so-called lithium metal secondary battery can be obtained. That is, high energy density can be obtained, and cycle characteristics and quick charge characteristics can be improved.

  In the secondary battery, when charged, lithium ions are released from the positive electrode 21 and are first inserted into the negative electrode material capable of inserting and extracting lithium contained in the negative electrode 22 through the electrolytic solution. When charging is further continued, lithium metal begins to deposit on the surface of the negative electrode material capable of inserting and extracting lithium in a state where the open circuit voltage is lower than the overcharge voltage. After that, lithium metal continues to deposit on the negative electrode 22 until charging is completed. Next, when discharging is performed, first, lithium metal deposited on the negative electrode 22 is eluted as ions, and is occluded in the positive electrode 21 through the electrolytic solution. When the discharge is further continued, lithium ions are released from the negative electrode material capable of inserting and extracting lithium in the negative electrode 22 and inserted into the positive electrode 21 through the electrolytic solution. Thus, in this secondary battery as well, since the deposition and dissolution of lithium metal are repeated in the negative electrode 22, the activity of the negative electrode 22 is very high. In this embodiment, however, the electrolyte solution is highly chemical even at high temperatures. Since it has stability, excellent high-temperature storage characteristics can be obtained.

(Fifth secondary battery)
FIG. 3 shows the configuration of the fifth secondary battery. This secondary battery is a so-called laminate film type, and has a wound electrode body 30 to which a positive electrode lead 31 and a negative electrode lead 32 are attached accommodated in a film-shaped exterior member 40.

  The positive electrode lead 31 and the negative electrode lead 32 are led out from the inside of the exterior member 40 to the outside, for example, in the same direction. The positive electrode lead 31 and the negative electrode lead 32 are each made of a metal material such as aluminum, copper, nickel, or stainless steel, and each have a thin plate shape or a mesh shape.

  The exterior member 40 is made of, for example, a rectangular aluminum laminated film in which a nylon film, an aluminum foil, and a polyethylene film are bonded together in this order. For example, the exterior member 40 is disposed so that the polyethylene film side and the wound electrode body 30 face each other, and the outer edge portions are in close contact with each other by fusion bonding or an adhesive. An adhesive film 41 is inserted between the exterior member 40 and the positive electrode lead 31 and the negative electrode lead 32 to prevent intrusion of outside air. The adhesion film 41 is made of a material having adhesion to the positive electrode lead 31 and the negative electrode lead 32, for example, a polyolefin resin such as polyethylene, polypropylene, modified polyethylene, or modified polypropylene.

  The exterior member 40 may be made of a laminated film having another structure, a polymer film such as polypropylene, or a metal film instead of the above-described aluminum laminated film.

  FIG. 4 shows a cross-sectional structure taken along line II of the spirally wound electrode body 30 shown in FIG. The electrode winding body 30 is obtained by laminating a positive electrode 33 and a negative electrode 34 via a separator 35 and an electrolyte layer 36 and winding them, and the outermost periphery is protected by a protective tape 37.

  The positive electrode 33 has a structure in which a positive electrode active material layer 33B is provided on both surfaces of a positive electrode current collector 33A. The negative electrode 34 has a structure in which a negative electrode active material layer 34B is provided on both surfaces of a negative electrode current collector 34A, and the negative electrode active material layer 34B and the positive electrode active material layer 33B are arranged to face each other. The configuration of the positive electrode current collector 33A, the positive electrode active material layer 33B, the negative electrode current collector 34A, the negative electrode active material layer 34B, and the separator 35 is the same as that of the positive electrode current collector 21A, the positive electrode active material in the first to fourth secondary batteries described above. This is the same as the material layer 21B, the negative electrode current collector 22A, the negative electrode active material layer 22B, and the separator 23.

  The electrolyte layer 36 includes an electrolytic solution according to the present embodiment and a polymer compound that serves as a holding body that holds the electrolytic solution, and has a so-called gel shape. A gel electrolyte is preferable because high ion conductivity can be obtained and battery leakage can be prevented. Examples of the polymer compound include, for example, an ether polymer compound such as polyethylene oxide or a crosslinked product containing polyethylene oxide, an ester polymer compound such as polymethacrylate, or an acrylate polymer compound, or polyvinylidene fluoride or vinylidene fluoride. Examples thereof include polymers of vinylidene fluoride such as a copolymer with hexafluoropropylene, and any one of these or a mixture of two or more thereof is used. In particular, from the viewpoint of redox stability, it is desirable to use a fluorine-based polymer compound such as a vinylidene fluoride polymer.

  For example, the secondary battery can be manufactured as follows.

  First, a precursor solution containing an electrolytic solution, a polymer compound, and a mixed solvent is applied to each of the positive electrode 33 and the negative electrode 34, and the mixed solvent is volatilized to form the electrolyte layer 36. Next, the positive electrode lead 31 is attached to the positive electrode current collector 33A, and the negative electrode lead 32 is attached to the negative electrode current collector 34A. Subsequently, the positive electrode 33 and the negative electrode 34 on which the electrolyte layer 36 is formed are laminated via a separator 35 to form a laminated body, and then the laminated body is wound in the longitudinal direction, and the protective tape 37 is attached to the outermost peripheral portion. The wound electrode body 30 is formed by bonding. After that, for example, the wound electrode body 30 is sandwiched between the exterior members 40, and the outer edge portions of the exterior members 40 are sealed and sealed by thermal fusion or the like. At that time, the adhesion film 41 is inserted between the positive electrode lead 31 and the negative electrode lead 32 and the exterior member 40. Thereby, the secondary battery shown in FIGS. 3 and 4 is completed.

  Further, this secondary battery may be manufactured as follows. First, the positive electrode 33 and the negative electrode 34 are prepared as described above, and after the positive electrode lead 31 and the negative electrode lead 32 are attached to the positive electrode 33 and the negative electrode 34, the positive electrode 33 and the negative electrode 34 are stacked via the separator 35 and wound. Rotate and adhere the protective tape 37 to the outermost periphery to form a wound body that is a precursor of the wound electrode body 30. Next, the wound body is sandwiched between the exterior members 40, and the outer peripheral edge portion excluding one side is heat-sealed to form a bag shape, and is stored inside the exterior member 40. Subsequently, an electrolyte composition including an electrolytic solution, a monomer that is a raw material of the polymer compound, a polymerization initiator, and other materials such as a polymerization inhibitor as necessary is prepared, and the interior of the exterior member 40 Then, the opening of the exterior member 40 is heat-sealed and sealed. Thereafter, heat is applied to polymerize the monomer to obtain a polymer compound, thereby forming the gel electrolyte layer 36, and assembling the secondary battery shown in FIGS.

  The operation of this secondary battery is the same as that of the first to fourth secondary batteries described above.

  As described above, according to the present embodiment, since the electrolyte solution contains carbonate fluoride and a small amount of carbonate chloride, the second to fifth secondary batteries also include the first. Similarly to the secondary battery, chemical stability at high temperatures can be improved, and high-temperature storage characteristics can be improved.

  Further, specific embodiments of the present invention will be described in detail.

(Examples 1-1 to 1-8)
The coin-type secondary battery shown in FIG. 5 was produced. This secondary battery is formed by laminating a positive electrode 51 and a negative electrode 52 via a separator 53 impregnated with an electrolytic solution, sandwiching between an outer can 54 and an outer cup 55 and caulking via a gasket 56. is there. First, 94 parts by mass of lithium cobalt composite oxide (LiCoO ₂ ) as a positive electrode active material, 3 parts by mass of graphite as a conductive agent, and 3 parts by mass of polyvinylidene fluoride as a binder were mixed, and then N-methyl as a solvent. -2-Pyrrolidone was added to obtain a positive electrode mixture slurry. Next, the obtained positive electrode mixture slurry was uniformly applied to a positive electrode current collector 51A made of an aluminum foil having a thickness of 20 μm and dried to form a positive electrode active material layer 51B. After that, the positive electrode current collector 51A on which the positive electrode active material layer 51B was formed was punched into a circle having a diameter of 16 mm to produce the positive electrode 51.

  A negative electrode active material layer 52B made of silicon was formed on the negative electrode current collector 52A made of a copper foil having a thickness of 15 μm by a sputtering method. After that, the negative electrode current collector 52A on which the negative electrode active material layer 52B was formed was punched into a circle having a diameter of 16 mm to produce the negative electrode 52. At that time, the amounts of the lithium cobalt composite oxide as the positive electrode active material and silicon as the negative electrode active material were adjusted so that lithium metal was not deposited on the negative electrode 52 even during full charge.

Next, after laminating the positive electrode 51 and the negative electrode 52 via a separator 53 made of microporous polyethylene having a thickness of 25 μm, 0.1 g of an electrolytic solution is injected into the separator 53, and these are attached to an exterior cup 55 made of stainless steel. The secondary battery shown in FIG. 5 was obtained by placing it in the outer can 54 and caulking them. The electrolytic solution was a mixture of 4-fluoro-1,3-dioxolan-2-one shown in Chemical Formula 2, which is a carbonate ester fluoride, and diethyl carbonate in a mass ratio of 5: 5, and LiPF ₆ was mixed. It was prepared by adding a concentration of 1 mol / l and adding 4-chloro-1,3-dioxolan-2-one which is a chloride of carbonate. At that time, the content of 4-chloro-1,3-dioxolan-2-one in the electrolyte solution was Examples 1-1 to 1-8, as shown in Table 1, from 5 ppm to 8000 ppm by mass. Varyed within range.

  As Comparative Example 1-1 with respect to the present example, except that 4-chloro-1,3-dioxolan-2-one was not added to the electrolytic solution, the rest was the same as Example 1-1 to 1-8. A secondary battery was manufactured. Moreover, as Comparative Example 1-2, except that the content of 4-chloro-1,3-dioxolan-2-one in the electrolytic solution was 10000 mass ppm (1 mass%), the others were Example 1- Secondary batteries were fabricated in the same manner as in 1 to 1-8. Furthermore, as Comparative Examples 1-3 and 1-4, ethylene carbonate was used in the electrolyte instead of 4-fluoro-1,3-dioxolan-2-one, and in Comparative Example 1-3, 4-chloro-1, Other than carrying out, except that 3-dioxolan-2-one was not added, and the content of 4-chloro-1,3-dioxolan-2-one in the electrolytic solution was set to 1000 mass ppm in Comparative Example 1-4 Secondary batteries were fabricated in the same manner as in Examples 1-1 to 1-8.

Regarding the fabricated secondary batteries of Examples 1-1 to 1-8 and Comparative Examples 1-1 to 1-4, the battery was charged at 1.77 mA with 4.2 V as the upper limit for 12 hours, and then rested for 10 minutes. 2 cycles of charge / discharge of discharging until reaching 2.5V at 77mA, charging again to 4.2V, storing at 60 ° C for 1 month, then repeating 50 cycles of charging / discharging again under the same conditions, after storage at high temperature The discharge capacity retention ratio at the 50th cycle was determined by Equation 1. The obtained results are shown in Table 1 and FIG.
(Formula 1)
50th cycle discharge capacity retention rate after high temperature storage = (50th cycle discharge capacity after high temperature storage / second cycle discharge capacity before high temperature storage) × 100

  As can be seen from Table 1 and FIG. 6, as the content of 4-chloro-1,3-dioxolan-2-one is increased, the discharge capacity retention rate after high-temperature storage is improved and decreased after showing a maximum value. The tendency to do was seen. In addition, according to this example using both 4-fluoro-1,3-dioxolan-2-one and 4-chloro-1,3-dioxolan-2-one, 4-fluoro-1,3-dioxolane Compared with Comparative Examples 1-3 and 1-4 that did not use 2-one, the characteristics could be greatly improved.

  That is, it was found that the high-temperature storage characteristics can be improved if the electrolytic solution contains a carbonate fluoride and a small amount of carbonate chloride.

(Examples 2-1 to 2-4, 3-1 to 3-4)
A secondary battery was fabricated in the same manner as in Examples 1-1 to 1-8, except that the mass ratio of 4-fluoro-1,3-dioxolan-2-one and diethyl carbonate in the electrolytic solution was changed. did. At that time, in Examples 2-1 to 2-4, 4-fluoro-1,3-dioxolan-2-one: diethyl carbonate = 7: 3, and in Examples 3-1 to 3-4, 4-fluoro -1,3-dioxolan-2-one: diethyl carbonate = 2: 8. The content of 4-chloro-1,3-dioxolan-2-one in the electrolytic solution was as shown in Tables 2 and 3 in Examples 2-1 to 2-4 and 3-1 to 3-4. In the range of 30 mass ppm to 5000 mass ppm.

  As Comparative Examples 2-1 and 3-1 for the present example, except that 4-chloro-1,3-dioxolan-2-one was not added to the electrolytic solution, other examples 2-1 to 2- Secondary batteries were fabricated in the same manner as 4,3-1 to 3-4. Moreover, as Comparative Examples 2-2 and 3-2, except that the content of 4-chloro-1,3-dioxolan-2-one in the electrolytic solution was 10000 mass ppm (1 mass%), Secondary batteries were fabricated in the same manner as in Examples 2-1 to 2-4 and 3-1 to 3-4.

  Also for the fabricated secondary batteries of Examples 2-1 to 2-4, 3-1 to 3-4 and Comparative Examples 2-1, 2-2, 3-1, 3-2, Examples 1-1 to In the same manner as in 1-8, the discharge capacity retention ratio at the 50th cycle after high-temperature storage was determined by Equation 1. The obtained results are shown in Tables 2 and 3 and FIG. FIG. 7 also shows the results of Examples 1-1 to 1-8.

  As can be seen from Tables 2 and 3 and FIG. 7, the same results as in Examples 1-1 to 1-8 were also obtained in this example. That is, it was found that if 4-fluoro-1,3-dioxolan-2-one is contained, the same effect can be obtained even if the content is changed.

(Examples 4-1 to 4-4, 5-1 to 5-4, 6-1 to 6-4)
A secondary battery was fabricated in the same manner as in Examples 1-1 to 1-8, except that the configuration of the negative electrode 52 was changed. At that time, as the negative electrode active material, CoSnC-containing material powder was used in Examples 4-1 to 4-4, artificial graphite powder was used in Examples 5-1 to 5-4, and Examples 6-1 to 6-4 were used. The negative electrode 52 was produced using lithium metal as follows.

  In Examples 4-1 to 4-4, 80 parts by mass of the CoSnC-containing material powder as the negative electrode active material, 11 parts by mass of graphite as the conductive agent and 1 part by mass of acetylene black, and polyvinylidene fluoride as the binder 8 After the mass part is dispersed in N-methyl-2-pyrrolidone as a solvent, the negative electrode current collector 52A made of a copper foil having a thickness of 10 μm is uniformly applied and dried to form the negative electrode active material layer 52B. A negative electrode 52 was produced by punching into a circle having a diameter of 16 mm.

  At that time, the CoSnC-containing material powder was synthesized using a mechanochemical reaction by mixing cobalt-tin alloy powder and carbon powder. When the composition of the obtained CoSnC-containing material was analyzed, the content of cobalt was 29.3 mass%, the content of tin was 49.9 mass%, the content of carbon was 19.8 mass%, The ratio Co / (Sn + Co) of cobalt to the total with cobalt was 37% by mass. The carbon content was measured by a carbon / sulfur analyzer, and the cobalt and tin contents were measured by ICP (Inductively Coupled Plasma) emission analysis. Further, when X-ray diffraction was performed on the obtained CoSnC-containing material, a diffraction peak having a wide half-width with a diffraction angle 2θ of 1.0 ° or more was observed between diffraction angles 2θ = 20 ° to 50 °. It was. Further, when XPS was performed on the CoSnC-containing material, a peak P1 was obtained as shown in FIG. When the peak P1 was analyzed, a peak P2 of surface contamination carbon and a peak P3 of C1s in the CoSnC-containing material on the lower energy side than the peak P2 were obtained. This peak P3 was obtained in a region lower than 284.5 eV. That is, it was confirmed that carbon in the CoSnC-containing material was bonded to other elements.

  In Examples 5-1 to 5-4, 95 parts by mass of artificial graphite powder as a negative electrode active material and 5 parts by mass of polyvinylidene fluoride as a binder were dispersed in N-methyl-2-pyrrolidone as a solvent. Then, it was uniformly applied to a negative electrode current collector 52A made of a copper foil having a thickness of 10 μm and dried to form a negative electrode active material layer 52B, and punched into a circle having a diameter of 16 mm to produce a negative electrode 52.

  In Examples 6-1 to 6-4, the negative electrode active material layer 52B was formed by attaching a lithium metal foil to the negative electrode current collector 52A made of a copper foil having a thickness of 15 μm, and the negative electrode 52 was produced. That is, Examples 6-1 to 6-4 are lithium metal secondary batteries in which the capacity of the negative electrode 52 is expressed by precipitation and dissolution of lithium.

  In Examples 4-1 to 4-4, 5-1 to 5-4, 6-1 to 6-4, the content of 4-chloro-1,3-dioxolan-2-one in the electrolyte solution is As shown in Tables 4-6, it was changed within the range of 30 ppm to 5000 ppm by mass.

  As Comparative Examples 4-1, 5-1 and 6-1 with respect to the present example, except that 4-chloro-1,3-dioxolan-2-one was not added to the electrolyte, Similarly, a secondary battery was produced. Further, as Comparative Examples 4-2, 5-2, and 6-2, the content of 4-chloro-1,3-dioxolan-2-one in the electrolytic solution was 10000 mass ppm (1 mass%). Except for this, a secondary battery was fabricated in the same manner as in this example. Further, as Comparative Examples 4-3, 4-4, 5-3, 5-4, 6-3, 6-4, ethylene carbonate was used instead of 4-fluoro-1,3-dioxolan-2-one in the electrolyte. In Comparative Examples 4-3, 5-3, and 6-3, 4-chloro-1,3-dioxolan-2-one was not added. In Comparative Examples 4-4, 5-4, and 6-4, A secondary battery was fabricated in the same manner as in this example, except that the content of 4-chloro-1,3-dioxolan-2-one in the electrolytic solution was 1000 ppm by mass.

  Examples 4-1 to 4-4, 5-1 to 5-4, 6-1 to 6-4 and Comparative Examples 4-1 to 4-4, 5-1 to 5-4, 6-1 to For the secondary battery of 6-4, the discharge capacity retention ratio at the 50th cycle after high temperature storage was determined by Equation 1 in the same manner as in Examples 1-1 to 1-8. The obtained results are shown in Tables 4 to 6 and FIGS.

  As can be seen from Tables 4 to 6 and FIGS. 9 to 11, the content of 4-chloro-1,3-dioxolan-2-one in this example was also the same as in Examples 1-1 to 1-8. As the value increased, the discharge capacity retention rate after high-temperature storage improved and showed a tendency to decrease after showing the maximum value. If 4-fluoro-1,3-dioxolan-2-one and 4-chloro-1,3-dioxolan-2-one are used together, 4-fluoro-1,3-dioxolane-2-one can be used. Compared with the case where ON is not used, the characteristics can be greatly improved. That is, it was found that the same effect can be obtained even when other negative electrode active materials are used.

  Although the present invention has been described with reference to the embodiments and examples, the present invention is not limited to the embodiments and examples, and various modifications can be made. For example, in the above-described embodiments and examples, the case where an electrolytic solution is used as the electrolyte is described. In the above-described embodiment, the case where a gel electrolyte in which the electrolytic solution is held in a polymer compound is used is also described. Other electrolytes may be used. Other electrolytes include, for example, a mixture of an ion conductive inorganic compound such as ion conductive ceramics, ion conductive glass or ionic crystal and an electrolytic solution, or a mixture of another inorganic compound and an electrolytic solution. Or a mixture of these inorganic compounds and a gel electrolyte.

  In the above embodiment and examples, a battery using lithium as an electrode reactant has been described. However, other alkali metals such as sodium (Na) or potassium (K), or alkalis such as magnesium or calcium (Ca) are used. The present invention can also be applied to the case of using an earth metal or another light metal such as aluminum. At that time, the negative electrode active material described in the above embodiment, for example, a material containing tin or silicon as a constituent element, or a carbon material can be used in the same manner for the negative electrode.

  Further, in the above-described embodiment or example, a cylindrical type, laminated film type, or coin type secondary battery has been specifically described, but the present invention has other shapes such as a button type or a square type. The present invention can be similarly applied to a secondary battery or a secondary battery having another structure such as a laminated structure. Further, the present invention is not limited to the secondary battery, and can be similarly applied to other batteries such as a primary battery.

It is sectional drawing showing the structure of the 1st secondary battery using the electrolyte solution which concerns on one embodiment of this invention. It is sectional drawing which expands and represents a part of winding electrode body in the secondary battery shown in FIG. It is a disassembled perspective view showing the structure of the 5th secondary battery using the electrolyte solution which concerns on one embodiment of this invention. It is sectional drawing showing the structure along the II line of the winding electrode body shown in FIG. It is sectional drawing showing the structure of the secondary battery produced in the Example. It is a characteristic view showing the relationship between the content of 4-chloro-1,3-dioxolan-2-one and the discharge capacity retention rate. It is a characteristic view showing the relationship between the content of 4-chloro-1,3-dioxolan-2-one, the discharge capacity retention rate, and the content of 4-fluoro-1,3-dioxolan-2-one. 1 shows an example of a peak obtained by X-ray photoelectron spectroscopy relating to a CoSnC-containing material produced in an example. It is another characteristic view showing the relationship between the content of 4-chloro-1,3-dioxolan-2-one and the discharge capacity retention rate. It is another characteristic view showing the relationship between the content of 4-chloro-1,3-dioxolan-2-one and the discharge capacity retention rate. It is another characteristic view showing the relationship between the content of 4-chloro-1,3-dioxolan-2-one and the discharge capacity retention rate.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Battery can, 12, 13 ... Insulation board, 14 ... Battery cover, 15 ... Safety valve mechanism, 15A ... Disc board, 16 ... Heat sensitive resistance element, 17 ... Gasket, 20, 30 ... Winding electrode body, 21, 33 , 51 ... positive electrode, 21A, 33A, 51A ... positive electrode current collector, 21B, 33B, 51B ... positive electrode active material layer, 22, 34, 52 ... negative electrode, 22A, 34A, 52A ... negative electrode current collector, 22B, 34B, 52B ... negative electrode active material layer, 23, 35, 53 ... separator, 24 ... center pin, 25, 31 ... positive electrode lead, 26, 32 ... negative electrode lead, 36 ... electrolyte layer, 37 ... protective tape, 40 ... exterior member, 41 ... adhesion film.

Claims (8)

A fluoride charcoal ester, an electrolyte for non-aqueous secondary battery comprising a solvent containing a chloride of carbonic acid ester,
The carbonate content of the carbonate in the electrolytic solution is in the range of 5 ppm to 8000 ppm by mass,
The electrolyte solution for a non-aqueous secondary battery, wherein the content of the carbonate ester fluoride in the solvent is in the range of 20% by mass to 70% by mass. 2. The electrolyte solution for a non-aqueous secondary battery according to claim 1, wherein a content of the carbonate of the carbonate in the electrolyte solution is within a range of 30 mass ppm to 5000 mass ppm. As the fluoride of the carbonic acid ester contains a fluoride of cyclic carbonate, a chloride of the carbonic acid ester contains a salt product of cyclic carbonate,
Furthermore, the low-viscosity solvent having a viscosity of 1 mPa · s or less contains at least one of a chain carbonate ester, a chain carboxylate ester, a ketone, an ether, a chain amide, and a chain carbamate ester. The electrolyte solution for nonaqueous secondary batteries of Claim 1 or Claim 2.   The cyclic carbonate fluoride is 4-fluoro-1,3-dioxolan-2-one, and the cyclic carbonate chloride is 4-chloro-1,3-dioxolan-2-one. The electrolyte solution for non-aqueous secondary batteries according to claim 3. An electrolyte is provided together with the positive electrode and the negative electrode,
The electrolytic solution contains, as a solvent, a carbonate ester fluoride and a carbonate ester chloride,
The carbonate ester chloride content in the electrolyte solution is in the range of 5 ppm to 8000 ppm by mass,
The non-aqueous secondary battery in which the content of the carbonate ester fluoride in the solvent is in the range of 20% by mass to 70% by mass.   6. The nonaqueous secondary battery according to claim 5, wherein the content of the carbonate ester chloride in the electrolytic solution is in a range of 30 mass ppm to 5000 mass ppm. As the fluoride of the carbonic acid ester contains a fluoride of cyclic carbonate, a chloride of the carbonic acid ester contains a salt product of cyclic carbonate,
The electrolyte further includes at least one of a chain carbonate ester, a chain carboxylate ester, a ketone, an ether, a chain amide, and a chain carbamate ester as a low viscosity solvent having a viscosity of 1 mPa · s or less. The nonaqueous secondary battery according to claim 5 or 6, which is contained.   The cyclic carbonate fluoride is 4-fluoro-1,3-dioxolan-2-one, and the cyclic carbonate chloride is 4-chloro-1,3-dioxolan-2-one. The nonaqueous secondary battery according to claim 7.

Images