JP2006228601A - Battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery capable of suppressing drop in discharge capacity. <P>SOLUTION: A polymer containing tertiary amine such as 4-vinyl pyridine/styrene copolymer and at least one kind of compound having the characteristic of tertiary amine is contained in the battery. Even if a free acid is generated in an electrolyte, the free acid is effectively removed with the unpaired electron of nitrogen contained in the polymer, and drop in discharge capacity is suppressed. By using a cyclic carbonate ester derivative having a halogen atom in the electrolyte, drop in the discharge capacity is more suppressed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a battery including an electrolyte solution together with a positive electrode and a negative electrode, and in particular, using lithium (Li) or the like as an electrolytic reactant.

  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 size and weight 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.

Recently, with the improvement in performance of portable electronic devices, further improvement in capacity has been demanded, and it is considered to use tin (Sn) or silicon (Si) instead of carbon material as the negative electrode active material. Has been. 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. In particular, it has been reported that a negative electrode in which a thin film of tin or silicon is formed on a current collector can maintain a relatively large discharge capacity without pulverization of the negative electrode active material even by insertion and extraction of lithium ( For example, see Patent Document 1).
International Publication No. WO01 / 031724 Pamphlet

  By the way, these batteries have a problem that the discharge capacity is reduced due to the generation of free acid in the electrolyte.

  The present invention has been made in view of such problems, and an object thereof is to provide a battery capable of suppressing a decrease in discharge capacity.

  The battery of the present invention includes an electrolyte together with a positive electrode and a negative electrode, and contains a polymer containing at least one of a tertiary amine and a compound having the properties of a tertiary amine.

  According to the battery of the present invention, since the polymer containing at least one of the tertiary amine and the compound having the properties of the tertiary amine is contained, unpaired electrons of nitrogen contained in the polymer Thus, the free acid can be effectively removed, and the decrease in discharge capacity can be suppressed.

  Further, if the electrolyte contains a cyclic carbonate derivative having a halogen atom, the discharge capacity can be further prevented from decreasing.

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

  FIG. 1 shows a cross-sectional structure of a secondary battery according to an embodiment of the present invention. This secondary battery is a so-called cylindrical type, and is a wound electrode in which a strip-like positive electrode 21 and a negative electrode 22 are laminated and wound inside a substantially hollow cylindrical battery can 11 via a separator 23. It has a body 20. 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 and 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 includes, for example, a positive electrode current collector 21A having a pair of opposed surfaces and a positive electrode active material layer 21B provided on both surfaces or one surface of the positive electrode current collector 21A. The positive electrode current collector 21A is made of a metal material such as aluminum, nickel, or stainless steel, for example. The positive electrode active material layer 21B includes, for example, a positive electrode material that can occlude and release lithium as an electrode reactant as a positive electrode active material.

As a cathode material capable of inserting and extracting lithium, for example, lithium cobalt oxide, a solid solution containing lithium nickelate, or these _{(Li (Ni x Co y Mn} z) O 2)) (x, y and z Of 0 <x <1, 0 <y <1, 0 <z <1, x + y + z = 1), or lithium composite oxide such as manganese spinel (LiMn ₂ O ₄ ), or lithium iron phosphate A phosphate compound having an olivine structure such as (LiFePO ₄ ) is preferred. This is because a high energy density can be obtained. Examples of positive electrode materials capable of inserting and extracting lithium include oxides such as titanium oxide, vanadium oxide and manganese dioxide, disulfides such as iron disulfide, titanium disulfide and molybdenum sulfide, polyaniline or Examples also include conductive polymers such as polythiophene. As the positive electrode material, one kind may be used alone, or two or more kinds may be mixed and used.

  The positive electrode active material layer 21B also contains, for example, a conductive agent, and may further contain a binder as necessary. Examples of the conductive agent include carbon materials such as graphite, carbon black, and ketjen black, and one or more of them are used in combination. In addition to the carbon material, a metal material or a conductive polymer material may be used as long as it is a conductive material. Examples of the binder include synthetic rubber such as styrene butadiene rubber, fluorine rubber or ethylene propylene diene rubber, or a polymer material such as polyvinylidene fluoride, and one or more of them are mixed. Used. For example, when the positive electrode 21 and the negative electrode 22 are wound as shown in FIG. 1, it is preferable to use a styrene butadiene rubber or a fluorine rubber having high flexibility as the binder.

  The negative electrode 22 includes, for example, a negative electrode current collector 22A having a pair of opposed surfaces, and a negative electrode active material layer 22B provided on both surfaces or one surface of the negative electrode current collector 22A.

  The negative electrode current collector 22A is made of, for example, a metal material such as copper (Cu), nickel, titanium (Ti), iron, or chromium (Cr).

  For example, the negative electrode active material layer 22B can occlude and release lithium as an electrode reactant as a negative electrode active material, and includes at least one of a metal element and a metalloid element as a constituent element. Contains. This is because a high energy density can be obtained by using such a negative electrode material. The negative electrode material may be a single element, alloy or compound of a metal element or metalloid element, or may have at least a part of one or more of these phases. 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.

  Examples of metal elements or metalloid elements constituting the negative electrode material include magnesium (Mg), boron (B), aluminum, gallium (Ga), indium (In), and silicon (Si) that can form an alloy with lithium. , Germanium (Ge), tin (Sn), lead (Pb), bismuth (Bi), cadmium (Cd), silver (Ag), zinc (Zn), hafnium (Hf), zirconium (Zr), yttrium (Y) , Palladium (Pd) or platinum (Pt). These may be crystalline or amorphous.

  Among these, as the negative electrode material, a material containing a 4B group metal element or a semimetal element in the short-period type periodic table as a constituent element is preferable, and at least one of silicon and tin is particularly preferable as a constituent element. This is because silicon and tin have a large ability to occlude and release lithium, and a high energy density can be obtained.

  As an alloy of tin, for example, as a second constituent element other than tin, silicon, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium (Ti), germanium, bismuth, antimony (Sb), And those containing at least one member selected from the group consisting of chromium. 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.

  The negative electrode active material layer 22B may be formed by a vapor phase method, a liquid phase method, or a baking method, or may be formed by coating. The firing method is a method in which a particulate negative electrode active material is mixed with a binder or a solvent, if necessary, and then heat-treated at a temperature higher than the melting point of the binder, for example. Among these, in the case of the vapor phase method, the liquid phase method, or the firing method, the negative electrode active material layer 22B and the negative electrode current collector 22A are preferably alloyed at least at a 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. .

  In the case of coating, in addition to the negative electrode active material, other materials such as a binder such as polyvinylidene fluoride and a conductive agent may be included. The same applies to the case of the firing method.

  Note that as the negative electrode active material, a carbon material capable of inserting and extracting lithium may be used, or these carbon materials and the above-described negative electrode material may be used together. The carbon material has very little change in the crystal structure that occurs during charging and discharging. For example, if used together with the negative electrode material described above, a high energy density can be obtained and excellent cycle characteristics can be obtained. This is preferable because it can function as a conductive agent.

  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.

  For example, the separator 23 is impregnated with an electrolytic solution that is a liquid electrolyte. The electrolytic solution contains, for example, a solvent and an electrolyte salt dissolved in the solvent.

  It is preferable to use a high dielectric constant solvent having a relative dielectric constant of 30 or more as the solvent. This is because the number of lithium ions can be increased.

  Examples of the high dielectric constant solvent include cyclic carbonates such as ethylene carbonate, propylene carbonate, and butylene carbonate, cyclic carboxylic acid esters such as γ-butyrolactone and γ-valerolactone, and cyclic amides such as 1-methyl-2-pyrrolidinone. , Cyclic carbamates such as 3-methyl-2-oxazolidinone, sulfur compounds such as tetramethylene sulfone or γ-propanesulfuron, or derivatives obtained by substituting at least part of hydrogen with halogen. Among these, a cyclic carbonate derivative having a halogen atom obtained by substituting a part of hydrogen of the cyclic carbonate with a halogen is preferable. This is because the effect of suppressing the decomposition reaction of the solvent is high and the reduction of the discharge capacity can be further suppressed. Specific examples of such carbonate derivatives include 4-fluoro-1,3-dioxolan-2-one, 4-chloro-1,3-dioxolan-2-one, 4-fluoromethyl-1, Examples include 3-dioxolan-2-one, 4-trifluoromethyl-1,3-dioxolan-2-one, and 4-methyl-5-fluoro-1,3-dioxolan-2-one. A cyclic carbonate derivative having an atom is preferred. This is because a higher effect can be obtained. Any one of the high dielectric constant solvents may be used alone, or two or more of them may be used in combination.

  Moreover, it is preferable to mix and use a low-viscosity solvent having a viscosity of 1 mPa · s or less as the high dielectric constant solvent. This is because high ion conductivity can be obtained. Examples of the low-viscosity solvent include linear carbonate esters such as dimethyl carbonate, diethyl carbonate, dipropyl carbonate, and ethyl methyl carbonate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, methyl butyrate, and methyl isobutyrate. Linear carboxylic acid esters such as N, N-dimethylacetamide, and linear carbamic acid esters such as methyl N, N-diethylcarbamate. Any one of these low-viscosity solvents may be used alone, or two or more thereof may be mixed and used.

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 (CF ₃ SO ₃ Li), bis (trifluoromethanesulfonyl) imidolithium ((CF ₃ SO ₂ ) ₂ NLi), tris (trifluoromethanesulfonyl) methyllithium ((CF ₃ SO ₂ ) ₃ CLi), or bis (pentafluoroethanesulfonyl) imidolithium ((C ₂ F ₅ SO ₂ ) ₂ NLi).

  In addition, this secondary battery contains a polymer containing at least one of a tertiary amine and a compound having the characteristics of a tertiary amine. Since this polymer has an unpaired electron in nitrogen, for example, free acid such as hydrofluoric acid contained in the generated free acid or cyclic carbonate derivative having a halogen atom can be removed. This is because a decrease in capacity can be suppressed. Further, this polymer is preferably one that does not dissolve in the electrolytic solution. This is because battery characteristics may be deteriorated. Specifically, 4-vinylpyridine / styrene copolymer having the structure shown in Chemical Formula 1 and the structure shown in Chemical Formula 2, 4- (N, N-dimethylaminomethyl)-having the structure shown in Chemical Formula 3 Anion exchange resin such as styrene / styrene copolymer or acrylic acid-2- (N, N-dimethylamino) ethyl copolymer having the structure shown in Chemical Formula 4, or poly (N-methylethyleneimine) There is. These polymers may be contained in any location as long as they are inside the battery. For example, a particulate polymer is contained in the battery, attached to the battery lid 14, or attached to the separator 23. May be.

  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, the negative electrode active material layer 22B is formed on the negative electrode current collector 22A to produce the negative electrode 22. The negative electrode active material layer 22B may be formed by, for example, any one of a vapor phase method, a liquid phase method, a baking method, and coating, or a combination of two or more thereof. When formed by a vapor phase method, a liquid phase method, or a firing method, the negative electrode active material layer 22B and the negative electrode current collector 22A may be alloyed at least at a part of the interface at the time of formation. An alloy may be formed by heat treatment under a non-oxidizing atmosphere.

  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 CVD (Chemical Vapor Deposition) A chemical vapor deposition method) or a plasma CVD method can be used. As the liquid phase method, a known method such as electrolytic plating or electroless plating can be used. As for the firing method, a known method can be used. For example, an atmosphere firing method, a reaction firing method, or a hot press firing method can be used. In the case of application, it can be formed in the same manner as the positive electrode 21.

  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, for example, a polymer containing at least one of a tertiary amine and a compound having the properties of a tertiary amine is sealed inside the battery can 11, and a battery lid is formed at the opening end of the battery can 11. 14. The safety valve mechanism 15 and the heat sensitive resistance element 16 are fixed by caulking through a gasket 17. Thereby, the secondary battery shown in FIG. 1 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. In this secondary battery, the discharge capacity is reduced due to the generation of free acid in the electrolyte. However, in the present embodiment, since it includes a polymer containing at least one of a tertiary amine and a compound having the characteristics of a tertiary amine, the unpaired electrons of nitrogen contained in the polymer Free acid is removed, and the reduction in discharge capacity is suppressed.

  FIG. 3 shows a configuration of a secondary battery according to another embodiment of the present invention. In this secondary battery, a wound electrode body 30 to which a positive electrode lead 31 and a negative electrode lead 32 are attached is accommodated in a film-like exterior member 40, and can be reduced in size, weight, and thickness. ing.

  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 wound electrode body 30 is obtained by stacking and winding a positive electrode 33 and a negative electrode 34 with a separator 35 and an electrolyte layer 36 interposed therebetween, and the outermost peripheral portion 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 one or 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 one surface or both surfaces of a negative electrode current collector 34A, and the negative electrode active material layer 34B side is disposed so as to face the positive electrode active material layer 33B. Yes. The configurations 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 are respectively the positive electrode current collector 21A, the positive electrode active material layer 21B, and the negative electrode current collector 22A. The same as the negative electrode active material layer 22B and the separator 23.

  The electrolyte layer 36 includes an electrolytic solution and a polymer compound serving as a holding body that holds the electrolytic solution, and has a so-called gel shape. The gel electrolyte layer 36 is preferable because high ion conductivity can be obtained and battery leakage can be prevented. The structure of the electrolytic solution (that is, the solvent and the electrolyte salt) is the same as that of the cylindrical secondary battery shown in FIG. Examples of the polymer compound include polyethylene polymer or an ether polymer compound such as 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.

  Note that any one of the insides of the battery includes a polymer containing at least one of the above-described tertiary amine and the compound having the properties of a tertiary amine, and the electrolyte contains a free acid. Even if this occurs, it is effectively removed, and a reduction in discharge capacity is suppressed.

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

  First, a precursor solution containing a solvent, an electrolyte salt, 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. After that, the positive electrode lead 31 is attached to the end of the positive electrode current collector 33A by welding, and the negative electrode lead 32 is attached to the end of the negative electrode current collector 34A by welding. Next, 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 a protective tape 37 is adhered to the outermost peripheral portion. Thus, the wound electrode body 30 is formed. Finally, for example, the wound electrode body 30 and a polymer containing at least one of tertiary amine and a compound having the characteristics of a tertiary amine are sandwiched between the exterior members 40, and the outer edge of the exterior member 40 The parts are sealed and sealed by heat 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 member 40 together with a polymer containing at least one of a tertiary amine and a compound having the properties of a tertiary amine, and the outer peripheral edge except one side is heat-sealed. And is stored in the exterior member 40. Subsequently, an electrolyte composition including a solvent, an electrolyte salt, 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 exterior member Inject into 40.

  After injecting the electrolyte composition, the opening of the exterior member 40 is heat-sealed and sealed in a vacuum atmosphere. Next, heat is applied to polymerize the monomer to obtain a polymer compound, thereby forming a gel electrolyte layer 36, and assembling the secondary battery shown in FIG.

  The operation of this secondary battery is the same as that of the cylindrical secondary battery shown in FIG.

  As described above, according to the battery according to the present embodiment, since the polymer containing at least one of the tertiary amine and the compound having the characteristics of the tertiary amine is contained, it is included in the polymer. The free acid can be effectively removed by the unpaired electrons of nitrogen, and a reduction in discharge capacity can be suppressed.

  Further, if the electrolyte contains a cyclic carbonate derivative having a halogen atom, the discharge capacity can be further prevented from decreasing.

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

(Examples 1-1 to 1-7)
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 having a thickness of 70 μm. 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 having a thickness of 5 μm was formed on the negative electrode current collector 52A made of copper foil having a thickness of 15 μm by vapor deposition. 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.

  Next, the positive electrode 51 and the negative electrode 52 were laminated through a separator 53 made of a microporous polypropylene film having a thickness of 25 μm, and then 0.1 g of an electrolytic solution was injected into the separator 53. After that, 0.1 g of a polymer containing a compound having the properties of a tertiary amine as an additive is placed in an outer cup 55 and an outer can 54 made of stainless steel, and they are caulked. The secondary battery shown in FIG. 5 was obtained. The electrolytic solution includes a high dielectric constant solvent, a low viscosity solvent, and lithium hexafluorophosphate that is an electrolyte salt. A high dielectric constant solvent: a low viscosity solvent: lithium hexafluorophosphate = 42: 42: 16. It was mixed at a mass ratio. Further, as shown in Table 1, the high dielectric constant solvent is 4-fluoro-1,3-dioxolan-2-one, 4-chloro-1,3-dioxolan-2-one, 4-methyl-5-fluoro- 1,3-dioxolan-2-one, ethylene carbonate, or propylene carbonate was used. Further, the low viscosity solvent was diethyl carbonate or methyl trimethyl acetate. Furthermore, the polymer containing a compound having the properties of a tertiary amine was a 4-vinylpyridine / styrene copolymer. 4-Fluoro-1,3-dioxolan-2-one and 4-chloro-1,3-dioxolan-2-one are those produced through ethylene carbonate through equimolar amounts of fluorine gas or chlorine gas. It was. Moreover, 4-methyl-5-fluoro-1,3-dioxolan-2-one used what was manufactured through an equimolar amount of fluorine gas or chlorine gas in propylene carbonate.

  As Comparative Examples 1-1 to 1-3 for Examples 1-1 to 1-7, except that the additive was not enclosed inside the battery, the others were the same as Examples 1-1 to 1-7 A secondary battery was produced. At that time, the electrolytic solution was the same as in Examples 1-1, 1-3, and 1-5. Further, as Comparative Example 1-4, secondary batteries were fabricated in the same manner as in Examples 1-1 to 1-7, except that triethylamine was used as an additive. At that time, the electrolytic solution was the same as in Example 1-1. Triethylamine is dissolved in the electrolytic solution.

  The obtained secondary batteries of Examples 1-1 to 1-7 and Comparative Examples 1-1 to 1-4 were charged at 1.77 mA with 4.2 V as the upper limit for 12 hours, and then rested for 10 minutes. Charging / discharging of discharging until it reached 2.5 V at .77 mA was repeated, and the discharge capacity maintenance rate at the 50th cycle was determined. The discharge capacity retention rate at the 50th cycle was calculated as (discharge capacity at the 50th cycle / initial discharge capacity) × 100.

  As can be seen from Table 1, according to Examples 1-1 to 1-7, a 4-vinylpyridine / styrene copolymer, which is a polymer containing a compound having the characteristics of a tertiary amine, was included in the battery. For example, Comparative Examples 1-1 to 1-3 not including this, or Comparative Example 1 including triethylamine which is not a polymer including at least one of tertiary amines and compounds having the properties of tertiary amines. Compared to 4, the discharge capacity retention rate was improved. Moreover, according to Examples 1-1 to 1-3, 1-5, and 1-6 using a cyclic carbonate derivative having a halogen atom, from Examples 1-4 and 1-7 that do not use this Also, a high value was obtained for the discharge capacity retention rate, and in particular, a high value was obtained in Examples 1-1, 1-2, 1-5, and 1-6 using a cyclic carbonate derivative having a fluorine atom. .

  That is, it has been found that if the battery contains a polymer containing at least one of tertiary amine and a compound having the properties of tertiary amine, the reduction in discharge capacity can be suppressed. . Furthermore, it has been found preferable to include a cyclic carbonate having a halogen atom, particularly a cyclic carbonate derivative having a fluorine atom, as the high dielectric constant solvent.

(Examples 2-1 to 2-7, 3-1 to 3-7, 4-1 to 4-4)
As Examples 2-1 to 2-7, a negative electrode active material layer 52B made of tin having a thickness of 5 μm was formed by sputtering on a negative electrode current collector 52A made of copper foil having a thickness of 15 μm, using tin as the negative electrode active material. A secondary battery was fabricated in the same manner as in Examples 1-1 to 1-7, except for the formation. Moreover, as Comparative Examples 2-1 to 2-3 with respect to Examples 2-1 to 2-7, except that the additive was not enclosed inside the battery, the others were the same as Examples 2-1 to 2-7 Thus, a secondary battery was produced. At that time, the electrolytic solution was the same as in Examples 2-1, 2-3, 2-5, that is, the same as in Examples 1-1, 1-3, 1-5. As Comparative Example 2-4, a secondary battery was fabricated in the same manner as in Examples 2-1 to 2-7, except that triethylamine was used as the additive. At that time, the electrolytic solution was the same as that of Example 2-1, that is, the same as that of Example 1-1.

  As Examples 3-1 to 3-7, a tin-cobalt alloy having a mass ratio of tin: cobalt = 72: 28 was used as the negative electrode active material, 94 parts by mass of this tin-cobalt alloy, and 3 parts by mass of graphite as a conductive agent. And 3 parts by mass of polyvinylidene fluoride as a binder, N-methyl-2-pyrrolidone as a solvent is added, and uniformly applied to a negative electrode current collector 52A made of a copper foil having a thickness of 15 μm and dried. A secondary battery was fabricated in the same manner as in Examples 1-1 to 1-7, except that the negative electrode active material layer 52B having a thickness of 70 μm was formed. Further, as Comparative Examples 3-1 to 3-3 for Examples 3-1 to 3-7, except that the additive was not enclosed inside the battery, other than that of Examples 3-1 to 3-7 Thus, a secondary battery was produced. At that time, the electrolytic solution was the same as in Examples 3-1, 3-3, 3-5, that is, the same as in Examples 1-1, 1-3, 1-5. As Comparative Example 3-4, a secondary battery was fabricated in the same manner as in Examples 3-1 to 3-7, except that triethylamine was used as the additive. At that time, the electrolytic solution was the same as that of Example 3-1, that is, the same as that of Example 1-1.

  As Examples 4-1 to 4-4, artificial graphite was used as a negative electrode active material, 97 parts by mass of this artificial graphite and 3 parts by mass of polyvinylidene fluoride as a binder were mixed, and N-methyl-2 was used as a solvent. Example 1-1 except that pyrrolidone was added and the negative electrode active material layer 52B having a thickness of 70 μm was formed by uniformly applying and drying the negative electrode current collector 52A made of a copper foil having a thickness of 15 μm, followed by drying. A secondary battery was produced in the same manner as ˜1-4. Further, as Comparative Examples 4-1 and 4-2 with respect to Examples 4-1 to 4-4, except that the additive was not added, the others were the same as in Examples 4-1 to 4-4. A secondary battery was produced. At that time, the electrolytic solution was the same as in Examples 4-1 and 4-3, that is, the same as in Examples 1-1 and 1-3. As Comparative Example 4-3, a secondary battery was fabricated in the same manner as in Examples 4-1 to 4-4, except that triethylamine was used as the additive. At that time, the electrolytic solution was the same as in Example 4-1, that is, the same as in Example 1-1.

  Examples 2-1 to 2-7, 3-1 to 3-7, 4-1 to 4-4 and comparative examples 2-1 to 2-4, 3-1 to 3-4, 4-1 to 4- For the secondary battery 3 as well, the discharge capacity retention ratio at the 50th cycle was determined in the same manner as in Examples 1-1 to 1-7. The results are shown in Tables 2-4.

  As can be seen from Tables 2 to 4, the same results as in Examples 1-1 to 1-7 were obtained. That is, even if other negative electrode active materials are used, if a polymer containing at least one of a tertiary amine and a compound having the properties of a tertiary amine is included in the battery, the discharge capacity can be reduced. It was found that the decrease can be suppressed. Furthermore, it has been found that it is preferable to include a cyclic carbonate having a halogen atom, particularly a cyclic carbonate derivative having a fluorine atom, as the high dielectric constant solvent.

  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, a coin-type secondary battery and a wound-structure secondary battery have been specifically described. However, the present invention is not limited to a square-type, sheet-type or card-type, or The present invention can be similarly applied to a secondary battery having a stacked structure in which a plurality of positive electrodes and negative electrodes are stacked. Further, the present invention is not limited to the secondary battery, and can be similarly applied to other batteries such as a primary battery.

  In the above embodiments and examples, the case where lithium is used as the electrode reactant has been described, but other group 1 elements in the long-period periodic table such as sodium (Na) or potassium (K), or magnesium Alternatively, the present invention can be applied to the case where a Group 2 element in a long-period periodic table such as calcium (Ca), another light metal such as aluminum, lithium, or an alloy thereof is used, and similar effects are obtained. Can be obtained. At that time, as the negative electrode active material, the negative electrode material described in the above embodiment can be used in the same manner.

It is sectional drawing showing the structure of the secondary battery 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 secondary battery which concerns on other embodiment of this invention. It is sectional drawing along the II line | wire of the winding electrode body shown in FIG. It is sectional drawing showing the structure of the secondary battery produced in the Example.

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, 56 ... 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, 54 ... Exterior can, 55 ... Exterior cup.

Claims (4)

A battery comprising an electrolyte together with a positive electrode and a negative electrode,
A battery comprising a polymer containing at least one of a tertiary amine and a compound having the characteristics of a tertiary amine.   The battery according to claim 1, wherein the polymer contains an anion exchange resin. The battery according to claim 1, comprising a polymer having the structure shown in Chemical Formula 1 and the structure shown in Chemical Formula 2.

  The battery according to claim 1, wherein the electrolyte contains a cyclic carbonate derivative having a halogen atom.

Images