JP4364066B2 - Non-aqueous electrolyte battery - Google Patents

Description

  The present invention relates to a nonaqueous electrolyte battery having a separator.

  Since the room temperature molten salt is a non-flammable and nonvolatile conductor, it is expected to be used as a non-aqueous electrolyte for a non-aqueous electrolyte battery.

  However, generally, a room temperature molten salt has a higher viscosity than an organic solvent and hardly penetrates the entire separator. For this reason, the ion movement resistance inside a separator becomes high and is inferior to a large current characteristic.

  Therefore, it is conceivable to use a high-porosity separator to facilitate penetration of room temperature molten salt and improve large current characteristics. However, a high-porosity separator is short-circuited due to physical contact between the positive electrode and the negative electrode. There was a problem of high fear.

Then, using the separator which laminated | stacked the low porosity layer and the high porosity layer is proposed (refer patent document 1).
JP 2002-319386 A

  As a result of intensive studies, the present inventors have found the following.

  First, using a separator having a layer structure in which the inner layer is a high-porosity layer and the outer layer sandwiching the inner layer is a low-porosity layer, it is conceivable to facilitate room temperature molten salt permeation and make short-circuiting difficult. However, it has been found that such a layered separator has the following problems.

  Usually, in order to improve capacity density, an electrode group composed of a separator, a negative electrode, and a positive electrode has a pressing step in the manufacturing process. For this reason, the separator is pressed, and in particular, a portion of the separator that is far from the container is pressed from multiple directions, and the room temperature molten salt is difficult to penetrate. On the other hand, the portion near the container in the separator is near the injection location of the room temperature molten salt or the bottom surface during injection, so that the room temperature molten salt is likely to penetrate. Therefore, even if a separator having a layer structure focused on a single separator is used, it is difficult to allow room temperature molten salt to permeate the entire separator.

  Moreover, even if it permeates at one end, the ambient temperature molten salt flows out of the part far from the container with charge / discharge, so that the cycle characteristics deteriorate. This is presumably because the part far from the container is pressed from multiple directions and it is difficult to hold the nonaqueous electrolyte. Further, in a separator having a layer structure focused on a single separator, an inner layer which is a high porosity layer is exposed at the end of the separator. For this reason, the nonaqueous electrolyte is more likely to flow out.

  In view of the above circumstances, an object of the present invention is to provide a nonaqueous electrolyte battery that maintains a large current characteristic and is excellent in cycle characteristics by using a separator that allows easy penetration and retention of a room temperature molten salt.

The nonaqueous electrolyte battery of the present invention includes a container, a nonaqueous electrolyte filled in the container and containing a room temperature molten salt, a positive electrode stored in the container, a negative electrode stored in the container, a negative electrode, and a positive electrode and an inner portion is Ru sandwiched, a separator and an outer portion located outside the region of the inner, the separator is the nonaqueous electrolyte is filled, and part of the outer portion of the inner It is characterized by a low porosity compared to the above.

  The present invention can provide a nonaqueous electrolyte battery that maintains a large current characteristic and is excellent in cycle characteristics.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol shall be attached | subjected to a common structure through embodiment, and the overlapping description is abbreviate | omitted. Each figure is a schematic diagram for promoting explanation and understanding of the invention, and its shape, dimensions, ratio, and the like are different from those of an actual device. However, these are in consideration of the following explanation and known techniques. The design can be changed as appropriate.

  The nonaqueous electrolyte battery according to the present embodiment includes a container, an electrode group including a positive electrode, a negative electrode, and a separator, and a nonaqueous electrolyte. In the present embodiment, a case where one electrode group is accommodated in one container will be described. Therefore, the above-mentioned “site far from the container” refers to “site located inside the electrode group”, and “site close to the container” refers to “site located outside the electrode group”.

  Hereinafter, the separator, the nonaqueous electrolyte, the negative electrode, the positive electrode, and the container will be described.

1) Separator The separator according to the present embodiment is characterized in that a portion located outside the electrode group has a lower porosity than a portion located inside the electrode group. These parts are formed with a planar structure that focuses on the structure of the entire nonaqueous electrolyte battery.

  Usually, the part located inside the electrode group in the separator is pressed from multiple directions, and the nonaqueous electrolyte is difficult to penetrate. However, according to the present embodiment, since the porosity is high, the nonaqueous electrolyte can be easily penetrated. Moreover, although the site | part located in the outer side of an electrode group in a separator is a low porosity, since it becomes a bottom face at the time of injection | pouring vicinity of a nonaqueous electrolyte, nonaqueous electrolyte penetration | infiltration is easy.

  Further, according to the present embodiment, pressure is applied from the outside having a low porosity to the inside having a high porosity. This inward pressure due to the difference in porosity has a penetration effect at the time of non-aqueous electrolyte injection, and has a non-aqueous electrolyte retention effect in the charge / discharge cycle.

  As described above, the separator according to the present embodiment facilitates the penetration and retention of a non-aqueous electrolyte having a high viscosity typified by a room temperature molten salt. For this reason, reduction of the ion movement resistance inside a separator can be maintained, and the large current characteristic and cycle characteristic of a nonaqueous electrolyte battery can be improved.

  As will be described later, since the structure of the separator of the present embodiment focuses on the structure of the entire nonaqueous electrolyte battery, it appropriately changes according to the shapes of the electrode group and the separator.

  The boundary between the part located outside the electrode group and the part located inside is described.

  The width of the portion located outside the electrode group is preferably 0.1% or more and 40% or less compared to the entire width of the separator.

  When the width of the portion located outside the electrode group is 0.1% or more compared to the total width of the separator, the pressure toward the inside due to the difference in porosity improves, and when it is 40% or less, the electrode has a high porosity. A portion located inside can be sufficiently secured, and the large current characteristics can be further improved.

  In addition, the boundary between the part located outside the electrode group and the part located inside may be changed stepwise. In this case, the center line of the region that changes in stages is set as the boundary line between the two parts.

  Next, the porosity will be described.

  The difference in porosity between the portion located outside and the portion located inside is preferably 5% or more, more preferably 20% or more.

  If the difference in porosity between the part located outside and the part located inside is 5% or more, the penetration effect and retention effect of the non-aqueous electrolyte are increased due to the improvement of the pressure toward the inside due to the difference in porosity, and 20% If it is above, the effect is further enhanced.

  Note that the difference in porosity between the portion located outside and the portion located inside is preferably 55% or less. This is because problems such as deterioration of the cycle characteristics of the nonaqueous electrolyte battery due to non-uniform distribution of current flowing through the electrode group are unlikely to occur.

  It is preferable that the porosity of the site | part located inside is 8% or more and 97% or less.

  If the porosity of the part located on the inside is 8% or more, the large current characteristics are improved due to the reduction of the ion transfer resistance inside the separator, and if it is 97% or less, a short circuit occurs due to physical contact between the negative electrode and the positive electrode. No fear of doing.

  In addition, it is preferable that the porosity of the site | part located outside is 3% or more and 80% or less. When the porosity of the portion located outside is 3% or more, it is easy to permeate the room temperature molten salt, and when it is 80% or less, it is easy to take a large difference in porosity.

Here, a method for measuring the porosity will be described. When the thickness of the separator is t (cm), the surface area is S (cm ² ), the true specific gravity of the material is ρ (g / cm ³ ), and the weight is w (g), the porosity is expressed by the following (formula 1). Calculated by

Porosity (%) = 100 − {(w / ρ / t / S) × 100} (Formula 1)

In addition, according to this measuring method, the local dispersion | variation in the porosity in each site | part is not considered. However, the local variation of the porosity is preferably within the above-described preferable porosity range, and is preferably within about 2% from the viewpoint of the uniformity of the current distribution.

  Next, materials will be described.

  In general, a microporous film having excellent ion permeability and mechanical strength, or a non-woven insulating thin film is used.

  Specifically, from non-aqueous electrolyte resistance, polyolefins such as polypropylene (hereinafter PP) and polyethylene (hereinafter PE), polyesters such as polyethylene terephthalate (hereinafter PET), polyvinylene terephthalate, polyimide, polyamide, glass fiber , Polyvinylidene fluoride, polytetrafluoroethylene, cellulose and the like.

  As will be described later in Examples, polyesters that have high wettability to room temperature molten salt and can reduce ion migration resistance are preferable, and PET is particularly preferable.

  In addition, the site | part located inside and the site | part located outside may be the same material, or may differ from each other.

  From the viewpoint of improving the large current characteristics, it is preferable that the portion located inside is PET. At this time, it is more preferable that the material of the part located outside is a polyolefin such as PP or PE. By placing the highly wettable PET on the inside and the lowly wettable polyolefin on the outside, the inward pressure increases. For this reason, the large current characteristic can be further improved by improving the permeation effect and the retention effect of the nonaqueous electrolyte.

  On the other hand, from the viewpoint of simplifying the manufacturing method, it is preferable that the portion located on the inner side and the portion located on the outer side are the same material.

  As a manufacturing method of the separator, when the site located inside and the site located outside are the same material, there are a method of heating the outside of the separator to lower the porosity of the portion, a method of joining separators having different porosity, etc. Can be mentioned. In the case where the portion located on the inner side and the portion located on the outer side are made of different materials, a method of joining separators made of different materials is exemplified.

2) Non-aqueous electrolyte The non-aqueous electrolyte of the present embodiment is characterized by containing a room temperature molten salt, and thus has a high viscosity.

  In general, the viscosity of normal temperature molten salt, which is expected to be applied to non-aqueous electrolytes, is 30 (mPa · s) or more and 300 (mPa · s) or less. Although it is different, it is about 50 (mPa · s) to 500 (mPa · s). This is largely different from the viscosity of a liquid non-aqueous electrolyte to which a general Li salt is added, that is, 5 (mPa · s) to 8 (mPa · s).

  Examples of the non-aqueous electrolyte include a normal temperature molten salt alone, a liquid non-aqueous electrolyte prepared by adding another organic solvent to the normal temperature molten salt, and a gel non-aqueous electrolyte in which a liquid non-aqueous electrolyte and a polymer material are combined. . The room temperature molten salt may be a single salt or a mixture of a plurality of salts. Moreover, you may add electrolyte, an additive, etc. suitably.

  The room temperature molten salt refers to a compound that can exist as a liquid at room temperature (15 to 25 ° C.) among organic salts composed of a combination of an organic cation and an anion. Examples of the room temperature molten salt include a room temperature molten salt that exists alone as a liquid, a room temperature molten salt that becomes a liquid when mixed with an electrolyte, and a room temperature molten salt that becomes a liquid when dissolved in an organic solvent. In general, the melting point of a room temperature molten salt used for a nonaqueous electrolyte battery is 25 ° C. or less.

  The organic cation generally has a quaternary ammonium skeleton.

  The organic cation is preferably at least one selected from imidazolium ions such as dialkylimidazolium ions (DI +) and trialkylimidazolium ions (TI +), tetraalkylammonium ions, alkylpyridinium ions and alkylpipedinium ions.

  Particularly, in the case of DI +, 1-ethyl-3-methylimidazolium ion (EMI +) is preferable, and in the case of TI +, 1,2-dimethyl-3-propylimidazolium ion (DMPI +) is preferable. In the case of tetraalkylammonium ions, dimethylethylmethoxyammonium ions (DMEMA +) are preferred. In the case of alkylpyridinium ions, 1-butylpyridinium ion (BP +) is preferred.

  Examples of anions include various organic and inorganic anions.

The anions are BF ₄ ⁻ , B (OOC—COO) ₂ −, PF ₆ ⁻ , CF ₃ SO ₃ ⁻ , CF ₃ (CF ₂ ) ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (CF ₃ CF ₂ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) (CF ₃ CF ₂ SO ₂ ) N ⁻ , (CF ₃ SO ₂ ) (CF ₃ CF ₂ CF ₂ SO ₂ ) N ⁻ , (CF ₃ SO ₂ ) (CF ₃ CF ₂ CF ₂ CFSO ₂ ) N ⁻ , (CF ₃ SO ₂ ) (CF ₃ CF ₂ (CF ₃ ) CFSO ₂ ) N ⁻ , (NC) ₂ N ⁻ , CF ₃ CO ₂ ⁻ , (CF ₃ SO _{2) 3} C ^- at least one is preferably selected from.

Preferred organic cation and anion combinations include dialkylimidazolium tetrafluoroborate (DI · BF ₄ ), dialkylimidazolium tristrifluoromethanesulfonylmethide (DI · C (CF ₃ SO ₂ ) ₃ ), hexafluoride Examples thereof include dialkylimidazolium phosphate (DI · PF ₆ ), trialkylimidazolium tristrifluoromethanesulfonylmethide (TI · C (CF ₃ SO ₂ ) ₃ ), and the like.

Particularly, DI · BF ₄ , DI · C (CF ₃ SO ₂ ) ₃ and TI · C (CF ₃ SO ₂ ) ₃ ) are excellent in ion conductivity, chemical stability and electrochemical stability, and are more preferable. . Among this, the case of _{DI · BF 4 EMI · BF 4} , DI · C (CF 3 SO 2) 3 where EMI · C of _{(CF 3 SO 2) 3,} TI · C (CF 3 SO 2) 3) In this case, DMPI · C (CF ₃ SO ₂ ) ₃ is preferable because it has a relatively low viscosity and excellent high-current characteristics and facilitates battery production.

  Examples of the organic solvent include cyclic carbonates such as propylene carbonate (PC) and ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), methyl ethyl carbonate (MEC), dipropyl carbonate (DPC), and the like. Chain carbonates, chain ethers such as dimethoxyethane (DME) and dietoethane (DEE), cyclic ethers such as tetrahydrofuran (THF) and dioxolane (DOX), and phosphate esters such as trimethyl phosphate and triethyl phosphate And γ-butyrolactone (GBL), acetonitrile (AN), sulfolane (SL) and the like alone or in combination.

  The mixing ratio of the organic solvent is preferably in the range of 0% by weight to 50% by weight with respect to the total weight of the nonaqueous electrolyte. If it is larger than 50% by weight, the effect of improving the safety by the room temperature molten salt cannot be obtained. From the viewpoint of improving safety, it is preferably within the range of 0.001% by weight to 20% by weight. In general, when the mixing ratio of the organic solvent exceeds 10% by weight, a marked decrease in viscosity is observed. For this reason, when the mixing ratio of the organic solvent is in the range of 0 wt% or more and 10 wt% or less, the effect of the present embodiment is particularly great.

  Examples of the polymer material include polyvinylidene fluoride (PVdF), polyacrylonitrile (PAN), polyethylene oxide (PEO), and the like.

The electrolyte is an alkali metal, alkaline earth metal, a cation of at least one selected from the group consisting of magnesium and aluminum, chloride anion (Cl-, ClO ₄ -), a bromide anion (Br @ -,), iodine Fluoride anion (I−), fluoride anion {BF ₄ −, PF ₆ −, CF ₃ SO ₃ ⁻ , (CF ₃ CF ₂ SO ₂ ) ₂ N ⁻ , or tristrifluoromethanesulfonylmethide ion (CF ₃ SO ₂ ) It consists of a combination of at least one kind of anion selected from the group consisting of ₃ C ⁻ , bisoxalatoborate anion (BOB−) and dicyanoamine anion (DCA−). In particular, it is preferable to use a lithium salt as the cation.

  The concentration of these electrolytes is preferably from 0.1 mol / L to 3.5 mol / L, more preferably from 0.5 mol / L to 3 mol / L. This is because when the concentration is less than 0.1 mol / L, the conductivity is hardly improved by the addition of an electrolyte, and when it exceeds 3.5 mol / L, the conductivity is lowered due to an increase in viscosity.

  The additive is preferably at least one selected from vinylene carbonate (VC), vinylene acetate (VA) and catechol carbonate (CC). These additives can form a chemically stable and low-resistance film on the surfaces of the positive electrode and the negative electrode, and can improve large current characteristics.

  The addition amount of the additive is preferably in the range of 0.01% by weight to 5.0% by weight. If the amount is less than 0.01% by weight, the effect of the additive cannot be obtained. If the amount is more than 5.0% by weight, the film of the additive becomes excessively thick, resulting in deterioration of the large current characteristics. A more preferable range of the addition amount is in the range of 0.1 wt% to 3.0 wt%.

3) Negative electrode The negative electrode has at least a negative electrode active material. In addition, you may have a negative electrode collector and the negative electrode layer carry | supported by the single side | surface or both surfaces of a negative electrode collector, and containing a negative electrode active material, a electrically conductive agent, and a binder.

  The negative electrode active material contains at least one metal element selected from the group consisting of alkali metals, alkaline earth metals, magnesium and aluminum, alkali metal ions, alkaline earth metal ions, magnesium and aluminum ions. Materials that can be occluded and released are listed.

  In particular, the case of a non-aqueous electrolyte battery in which charging / discharging is performed by moving lithium ions between a negative electrode and a positive electrode will be described.

  The negative electrode active material is a lithium alloy such as lithium metal or lithium-aluminum alloy. Examples of the lithium alloy include an alloy of Li and at least one element selected from Si, Sn, Al, B, Ga, In, Pb, Bi, and Sb.

Examples of substances capable of occluding and releasing lithium ions include iron sulfide (FeS), iron disulfide (FeS2), titanium disulfide (TiS2), molybdenum oxide (MoO2), lithium titanate (Li4Ti5O12), carbonaceous materials, Examples thereof include nitrides including Li and Co or Ni such as Li _2.6 Co _0.4 N, Li _2.5 Ni _0.5 N, and Si / C composite materials including C and Si or SiO.

  Examples of the carbonaceous material include graphite, isotropic graphite, coke, carbon fiber, spherical carbon, resin-fired carbon, and pyrolytic vapor grown carbon. Among them, a carbon fiber using mesophase pitch as a raw material and a negative electrode including spherical carbon can improve cycle characteristics because of high charging efficiency, and are preferable. Furthermore, the orientation of carbon fibers made from mesophase pitch or spherical carbon graphite crystals is preferably radial. Carbon fibers and spherical carbon made from mesophase pitch are carbonized by heat-treating raw materials such as petroleum pitch, coal tar and resin at 550 ° C. to 2000 ° C., or graphite by heat treatment at 2000 ° C. or higher. Can be produced.

The carbonaceous material preferably has an interplanar spacing d002 of (002) planes of graphite crystals obtained from X-ray diffraction peaks in the range of 0.3354 nm or more and 0.40 nm or less. Although it depends largely on the type of carbonaceous material, the specific surface area of the carbonaceous material is preferably 0.5 m ² / g or more and 1000 m ² / g or less when using the BET (Brunauer, Emmett, Teller) method, still more preferably 1 m ² / g or more 200 meters ² / g or less.

  A carbon material can be used as a conductive agent for enhancing electron conductivity and suppressing contact resistance with the current collector. As the conductive agent, a highly conductive substance is preferable. As the carbon material used as the conductive agent, for example, carbon black such as acetylene black is preferably used for the negative electrode. Note that when the negative electrode active material has sufficient conductivity, the conductive agent may not be used.

  Examples of the binder for binding the negative electrode active material and the conductive agent include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), fluorine rubber, and styrene butadiene rubber.

  Regarding the mixing ratio of the negative electrode active material, the conductive agent, and the binder, the negative electrode active material is 70% by weight to 96% by weight, the conductive agent is 2% by weight to 28% by weight, and the binder is 2% by weight to 28% by weight. It is preferable to make it into the range below weight%. If the amount of the conductive agent is less than 2% by weight, the conductivity of the negative electrode layer is lowered, and the large current characteristics of the nonaqueous electrolyte battery are lowered. On the other hand, when the amount of the binder is less than 2% by weight, the binding property between the negative electrode layer and the negative electrode current collector is lowered, and the cycle characteristics are lowered. On the other hand, from the viewpoint of increasing the capacity, the conductive agent and the binder are each preferably 28% by weight or less.

  As the negative electrode current collector, different materials are used depending on the Li storage / release potential of the negative electrode active material. For example, the negative electrode current collector preferably uses copper when the negative electrode active material is a carbonaceous material, uses nickel when the negative electrode active material is Li metal, and uses aluminum when the negative electrode active material is lithium titanate. .

  The negative electrode is produced, for example, by suspending a negative electrode active material, a conductive agent, and a binder in a widely used solvent, applying the suspension to a current collector, drying, and pressing.

4) Positive electrode The positive electrode has at least a positive electrode active material. In addition, you may have a positive electrode electrical power collector and the positive electrode layer carry | supported by the single side | surface or both surfaces of a positive electrode electrical power collector and containing a positive electrode active material, a electrically conductive agent, and a binder.

  Examples of the positive electrode active material include oxides, sulfides, and conductive polymers, and one or more of these are used.

For example, oxides include manganese dioxide (MnO ₂ ) occluded Li, iron oxide, copper oxide, nickel oxide, copper oxyphosphate (Cu ₄ O (PO ₄ ) ₂ ), silver vanadate (AgV ₄ O ₁₁ ) , Divanadium pentoxide (V ₂ O ₅ ), silver chromate (Ag ₂ Cr ₂ O ₄ ), iron sulfate (Fe ₂ (SO ₄ ) ₃ ), vanadium oxide (eg V ₂ O ₅ ), and lithium Manganese composite oxide (for example, Li _x Mn ₂ O ₄ or Li _x MnO ₂ ), lithium nickel composite oxide (for example, Li _x NiO ₂ ), lithium cobalt composite oxide (Li _x CoO ₂ ), lithium nickel cobalt composite oxide (Eg, LiNi _1-y Co _y O ₂ ), lithium manganese cobalt composite oxide (eg, LiMn _y Co _1-y O ₂ ), spinel type lithium manganese nickel composite oxide (eg, Li _x Mn _2-y Ni _y O ₄ ), lithium-nickel-cobalt-aluminum composite oxide (e.g., _{LiNi 1-xy Co x Al y} O 2), lithium Manganese cobalt nickel complex oxide (e.g., _{LiMn x Co 2-xy Ni y} O 4). Lithium phosphorus oxide having an olivine structure (e.g., _{Li x FePO 4, Li x Fe} 1-y Mn y PO 4, Li x CoPO 4) , and the like.

  For example, examples of the sulfide include iron disulfide, iron sulfide, copper sulfide, and sulfur dioxide.

  For example, examples of the conductive polymer include polyaniline and polypyrrole, and disulfide polymer materials.

  In addition, sulfur (S), carbon fluoride, copper fluoride, copper chloride, and the like can be used.

  Examples of the conductive agent for increasing the conductivity and suppressing the contact resistance with the current collector include carbon black such as acetylene black, ketjen black, and furnace black, and graphite.

  Examples of the binder for binding the positive electrode active material and the conductive agent include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), ethylene-propylene-diene copolymer (EPDM), and styrene-butadiene rubber. (SBR), fluorine rubber, and the like.

  Regarding the compounding ratio of the positive electrode active material, the conductive agent, and the binder, the positive electrode active material is 80% by weight to 95% by weight, the conductive agent is 3% by weight to 20% by weight, and the binder is 2% by weight to 7%. It is preferable to be in the range of wt% or less. For the conductive agent, the effect described above can be exhibited by being 3% by weight or more, and by reducing the content to 20% by weight or less, the decomposition of the nonaqueous electrolyte on the surface of the conductive agent under high temperature storage is reduced. be able to. When the binder is 2% by weight or more, sufficient electrode strength can be obtained, and when it is 7% by weight or less, the blending amount of the electrode insulator can be reduced and the internal resistance can be reduced.

  The positive electrode current collector is preferably an aluminum foil or an aluminum alloy foil.

  The positive electrode is produced, for example, by suspending a positive electrode active material, a conductive agent, and a binder in an appropriate solvent, applying the suspension to a positive electrode current collector, drying, and pressing.

5) Container Examples of the container include a laminate film having a thickness of 0.2 mm or less and a metal container having a thickness of 0.5 mm or less. The wall thickness is more preferably 0.2 mm or less. Examples of the shape include a flat type, a square type, a cylindrical type, a coin type, a button type, a sheet type, and a laminated type. Of course, in addition to a small battery mounted on a portable electronic device or the like, a large battery mounted on an electric vehicle or the like may be used.

  The laminate film is a multilayer film composed of a metal layer and a resin layer covering the metal layer. In order to reduce the weight, the metal layer is preferably an aluminum foil or an aluminum alloy foil. The resin layer is for reinforcing the metal layer, and a polymer such as polypropylene (PP), polyethylene (PE), nylon, polyethylene terephthalate (PET), or the like can be used. The laminate film is formed by sealing by heat sealing.

  Examples of the metal container include aluminum or an aluminum alloy. As the aluminum alloy, an alloy containing elements such as magnesium, zinc and silicon is preferable. On the other hand, transition metals such as iron, copper, nickel, and chromium are preferably 100 ppm or less.

  Hereinafter, an example of a coin-type nonaqueous electrolyte battery including a cylindrical and flat type nonaqueous electrolyte battery including a wound electrode group and a stacked electrode group will be described in detail.

(First embodiment)
The wound cylindrical nonaqueous electrolyte battery according to the first embodiment will be described with reference to FIGS. 1 and 2A.

  FIG. 1 is a partially cutaway side view of the wound cylindrical nonaqueous electrolyte battery according to the first embodiment.

  In the bottomed cylindrical container 11 made of metal, an insulator 12 is disposed at the bottom, and an electrode group 13 is accommodated on the insulator 12. The electrode group 13 includes a positive electrode 14, a separator 15, and a negative electrode 16, and the positive electrode 14 and the negative electrode 16 are wound in a spiral shape with the negative electrode 16 serving as an outermost shell through the separator 15. In addition, since an insulating layer is interposed between the outermost shell of the electrode group 13 and the inner wall of the container 11, it is not electrically connected.

  The container 11 is filled with a nonaqueous electrolyte. The insulating paper 17 having an open center is disposed above the electrode group 13 in the container 11. The insulating sealing plate 18 is disposed in the upper opening of the container 11, and the insulating sealing plate 18 is fixed to the container 11 by caulking the vicinity of the upper opening of the container 11 inside. The positive terminal 19 is fitted in the center of the insulating sealing plate 18. One end of the positive electrode lead 110 is connected to the positive electrode 14, and the other end is connected to the positive electrode terminal 19. The negative electrode 6 is connected to the container 1 which is a negative electrode terminal via a negative electrode lead (not shown).

  Note that the insulating layer between the outermost shell of the electrode group 13 and the inner wall of the container 11 only needs to be able to block the electrical connection between them, and can be bonded to the inner wall of the container 11 or to the electrode group 13. It doesn't matter. When a laminate film made of a metal layer and a resin layer covering the metal layer is used as the container 11, the resin layer becomes an insulating layer between the outermost shell of the electrode group 13 and the inner wall of the container 11.

  FIG. 2A is a schematic view of the surface of the separator according to the first embodiment.

  As shown in FIG. 2A, since the electrode group 13 has a wound structure, the separator 15 has a strip shape. In the first embodiment, the outside of the electrode group 13 indicates the upper bottom surface and the lower bottom surface of the cylindrical electrode group. Therefore, in the separator 15, the part 15 a located outside the electrode group indicates a band-shaped end portion that sandwiches the part 15 b located inside the electrode group in the width direction of the separator. W indicates the width of the separator, and Wa indicates the end width.

  According to the first embodiment, the upper bottom surface of the wound cylindrical electrode group is a non-aqueous electrolyte injection location, and the lower bottom surface is a location where the non-aqueous electrolyte accumulates at the time of injection, so that penetration is easy.

  In addition, according to the first embodiment, it is possible to stop the nonaqueous electrolyte from flowing out toward the upper bottom surface and the lower bottom surface by the inward pressure due to the porosity difference, and it is easy to hold the nonaqueous electrolyte. It is.

(Modification 1)
In Modification 1, a wound cylindrical non-aqueous electrolyte battery using a separator whose outer peripheral end also has a low porosity will be described with reference to FIG. 2B with respect to a different point from the first embodiment.

  FIG. 2B is a schematic diagram of the surface of the separator according to the first modification.

  In the first modification, the outside of the electrode group 13 refers to the outer peripheral end, the upper bottom surface, and the lower bottom surface of the cylindrical electrode group. Accordingly, as shown in FIG. 2 (b), in the separator 15, the portion 15a located outside the electrode group is a band-like end portion sandwiching the outer peripheral end and the portion 15b located inside the electrode group in the width direction of the separator. It becomes.

  According to the first modification, the inflow of the nonaqueous electrolyte in the outer peripheral direction can be stopped by the inward pressure due to the difference in porosity, and the nonaqueous electrolyte can be further retained.

  The wound cylindrical non-aqueous electrolyte battery of Modification 1 is more effective when the outermost shell of the electrode group 13 is a separator.

  The nonaqueous electrolyte impregnated in the outermost shell separator does not contribute to charge / discharge, and the outermost shell separator serves only as an insulating layer. Therefore, in order to reduce the risk of short circuit, it is preferable that the porosity of the separator in the outermost shell portion is low.

(Second Embodiment)
A wound flat type nonaqueous electrolyte battery according to the second embodiment will be described with reference to FIGS. 3 and 4A.

  FIG. 3 is a partially cutaway perspective schematic view of a wound flat type nonaqueous electrolyte battery according to the second embodiment.

  As shown in FIG. 3, the positive electrode 24 and the negative electrode 26 constitute a flat electrode group 23 wound in a spiral shape so that the negative electrode 26 becomes an outermost shell through a separator 25. The positive electrode 24 is provided on the back side of the separator and is shown by a dotted line for convenience. These outer peripheral ends are the separator 25, the positive electrode 24, and the negative electrode 26 in order from the outer peripheral side. A positive electrode terminal 29 is bonded in the vicinity of the outer peripheral end of the positive electrode 24, and a negative electrode terminal 210 is bonded in the vicinity of the outer peripheral end of the negative electrode 26. The electrode group is stored in a container 21 filled with a nonaqueous electrolyte.

  FIG. 4A is a schematic view of the surface of the separator according to the second embodiment.

  As shown to Fig.4 (a), since the electrode group 23 takes a winding structure, the separator 25 becomes strip | belt shape. In the second embodiment, the outside of the electrode group 23 indicates a curved portion, an upper bottom surface, and a lower bottom surface of the electrode group 23. Therefore, in the separator 25, the part 25a located outside the electrode group is a band-shaped end part sandwiching the curved part of the electrode group and the part 25b located inside the electrode group in the width direction of the separator. W indicates the width of the separator, and Wa indicates the end width.

  According to the second embodiment, since the upper bottom surface of the wound flat electrode group is a non-aqueous electrolyte injection location and the lower bottom surface is a location where the non-aqueous electrolyte is accumulated at the time of injection, penetration is easy.

  Also, in the wound flat type non-aqueous electrolyte battery, the electrode plane portion is more prominently expanded and contracted during the charge / discharge reaction than the electrode bend portion due to the structure. Pressure is generated and the nonaqueous electrolyte flows out. However, according to the second embodiment, an inward pressure due to a difference in porosity is generated in the opposite direction to this pressure, so that the non-aqueous electrolyte can be held uniformly.

(Modification 2)
In Modification 2, a wound flat type non-aqueous electrolyte battery using a separator whose outer peripheral end also has a low porosity will be described with reference to FIG. 4B with respect to different points from the second embodiment.

  FIG. 4B is a schematic diagram of the surface of the separator according to the second modification.

  In the second modification, the outer side of the electrode group 23 is an outer peripheral end, a curved portion, an upper bottom surface, and a lower bottom surface of the flat electrode group. Therefore, as shown in FIG. 2B, in the separator 25, the portion 25a located outside the electrode group is different from the outer peripheral end of the electrode group 23, the curved portion, and the portion 25b located inside the electrode group. It becomes a band-shaped end portion sandwiched in the direction.

  According to the second modification, the inflow of the nonaqueous electrolyte in the outer peripheral direction can be stopped by the inward pressure due to the porosity difference, and the nonaqueous electrolyte can be further retained.

  The wound cylindrical non-aqueous electrolyte battery of Modification 2 is further effective when the outermost shell of the electrode group 23 is a separator.

  The nonaqueous electrolyte impregnated in the outermost shell separator does not contribute to charge / discharge, and the outermost shell separator serves only as an insulating layer. Therefore, in order to reduce the risk of short circuit, it is preferable that the porosity of the separator in the outermost shell portion is low.

(Third embodiment)
A laminated coin type nonaqueous electrolyte battery according to the third embodiment will be described with reference to FIGS.

  FIG. 5 is a schematic cross-sectional view of a laminated coin-type nonaqueous electrolyte battery according to the third embodiment.

  A positive electrode lead 39 is provided on the bottom surface of the container 31. The positive electrode 34 is electrically connected to the container 31 via the positive electrode lead 39. The negative electrode 36 is electrically connected to the negative electrode sealing plate 310. The positive electrode 34 and the negative electrode 36 are in positions facing each other with the separator 35 interposed therebetween. The container 31 and the negative electrode sealing plate 310 are electrically insulated by an insulating gasket 32, and the coin-type battery is sealed by the insulating gasket 32. The non-aqueous electrolyte is present in the separator 35, the positive electrode 34, the negative electrode 36, or the void inside the coin-type battery.

  FIG. 6 is a schematic view of the surface of the separator according to the third embodiment.

  As shown in FIG. 6, since the electrode group 33 has a laminated structure, the separator 35 is circular. Therefore, in the separator 35, the part 35a located outside the electrode group 33 surrounds the part 15b located inside the electrode group and becomes a donut-shaped end part in contact with the outer edge. W indicates the diameter of the separator, and Wa indicates the end width.

  Further, according to the third embodiment, the non-aqueous electrolyte can be prevented from flowing out in the layer direction due to the inward pressure due to the porosity difference, and the non-aqueous electrolyte can be easily held.

  Regardless of the coin type, in the case of a stacked electrode group, the portion located outside the electrode group is the outer edge of the separator. In addition, examples of the portion located outside the electrode group include a separator that forms the uppermost layer and the lowermost layer of the stacked electrode group.

  Examples will be described below, but the present invention is not limited to the examples described below unless the gist of the present invention is exceeded.

  In tests A to C, the high current characteristics and the cycle characteristics were examined for the nonaqueous electrolyte batteries of the type corresponding to the first to third embodiments. In test D, the wettability of the separator was investigated.

(Test A)
First, a wound cylindrical nonaqueous electrolyte battery shown in Example A1 was produced using the manufacturing method described below.

<Preparation of positive electrode>
91 parts by weight of lithium cobalt oxide (LiCoO 2) powder as a positive electrode active material, 2.5 parts by weight of acetylene black (Model No. FX35 manufactured by Denki Kagaku Kogyo) as a conductive agent, and 2.5 parts by weight of graphite as a conductive agent Then, 3 parts by weight of polyvinylidene fluoride (PVdF) as a binder was mixed in an N-methylpyrrolidone (NMP) solution to prepare a slurry. The obtained slurry was applied to a current collector made of an aluminum foil having a thickness of 15 μm, dried, and pressed to prepare a positive electrode having an electrode density of 3.0 g / cm 3 and an electrode width of 58.5 mm.

<Production of negative electrode>
85 parts by weight of lithium titanium oxide (Li4Ti5O12) powder as a negative electrode active material, 5 parts by weight of graphite as a conductive agent, 3 parts by weight of ketjen black as a conductive agent, and 7 parts by weight of PVdF as a binder Were mixed in N-methylpyrrolidone (NMP) solution to prepare a slurry. The obtained slurry was applied to a current collector made of an aluminum foil having a thickness of 15 μm, dried, and pressed to prepare a negative electrode having an electrode density of 2.0 g / cm 3 and an electrode width of 59.0 mm.

<Preparation of separator>
For separators made of PET nonwoven fabric with a width of 60.66 mm and a porosity of 95%, each end 0.36 mm is heated at 85 ° C. until it reaches 0.03 mm, and is placed outside the electrode group with an end width of 0.03 mm and a porosity of 40%. A separator shown in FIG. 2A having a width of 60 mm and a thickness of 50 μm including a portion positioned inside an electrode group having an internal width of 59.94 mm and a porosity of 95%, sandwiched between the positioned portions was prepared.

<Production of electrode group>
After laminating the positive electrode, the separator, the negative electrode, and the separator in this order, they were wound into a cylindrical shape so that the negative electrode became the outermost shell, thereby preparing an electrode group.

<Production of nonaqueous electrolyte battery>
Each electrode group is housed in a cylindrical container made of stainless steel, and a nonaqueous electrolyte prepared by adding 2M LiBF4 as an electrolyte to 1-ethyl-3methylimidazolium tetrafluoroboron (EMI.BF4) is injected. A cylindrical wound nonaqueous electrolyte battery having the structure shown in FIG. 1 was assembled.

  Example A2 to Example A2 were the same as Example A1 except that the separator end, interior, outer shell porosity, material, end width Wa and electrode group outermost shell were changed as shown in Table 1. 18 and the cylindrical wound nonaqueous electrolyte battery shown in Comparative Examples A1 and A-2 were assembled.

  In addition, the separator which material differs in an edge part and an inner side joined and produced each material.

  Although not shown in Table 1, the separator of Comparative Example 2 includes an inner layer made of PP with a porosity of 90% and a thickness of 30 μm and an outer layer made of PE with a porosity of 60% and a thickness of 10 μm sandwiching the inner layer. .

  With respect to the obtained nonaqueous electrolyte batteries of Examples A1 to 18 and Comparative Examples A1 to A2, large current characteristics and cycle characteristics were evaluated as follows.

<Evaluation of large current characteristics>
For a non-aqueous electrolyte battery, a constant current-constant voltage charge was performed up to 2.8 V at 0.2 CmA in an environment of 20 ° C., and then the battery voltage reached 1 V when discharged at 0.2 CmA at 20 ° C. The discharge capacity was 100. Then, after performing constant current-constant voltage charging at 0.2 CmA to 2.8 V in a 20 ° C. environment, the discharge capacity was measured when the battery voltage reached 1 V at 20 ° C. and discharging at 1 CmA. did. The results are also shown in Table 1.

<Cycle characteristic evaluation>
About the nonaqueous electrolyte battery, after charging for 10 hours to 2.8V at 0.2 CmA in a 20 degreeC environment, the charging / discharging cycle which discharges to 1V at 0.2 CmA was given. The cycle life was determined when the discharge capacity dropped to 80% of the discharge capacity at the first cycle. The results are also shown in Table 1.

  As shown in Table 1, Examples A1 to A18 are excellent in cycle life as compared with Comparative Examples A1 to A2. Therefore, it can be seen that the non-aqueous electrolyte battery of the present embodiment can improve the cycle characteristics.

  In addition, Examples A2 to A6 are further superior in discharge capacity ratio and cycle life as compared to Example A1. Therefore, it can be seen that the large current characteristic and the cycle characteristic are further improved when the ratio of the end width to the total width is 0.1% or more and 40% or less.

  In addition, Examples A9 to A13 are superior in discharge capacity ratio compared to Examples A7 to A8. Therefore, it can be seen that the large current characteristic is further improved when the difference in porosity between the portion located outside and the portion located inside is 5% or more.

  In addition, Examples A11 to A13 are superior in cycle life as compared to Examples A7 to A10. Therefore, it can be seen that the cycle characteristics are further improved when the difference in porosity between the portion located outside and the portion located inside is 20% or more.

  In addition, Example A17 is superior in discharge capacity ratio to Example A18. Therefore, it can be seen that the use of a separator having a low porosity at the outer peripheral end further improves the large current characteristics.

(Test B)
First, a wound flat non-aqueous electrolyte battery shown in Example B1 was produced using the manufacturing method described below.

<Preparation of positive electrode>
91 parts by weight of lithium cobalt oxide (LiCoO 2) powder as a positive electrode active material, 2.5 parts by weight of acetylene black (Model No. FX35 manufactured by Denki Kagaku Kogyo) as a conductive agent, and 2.5 parts by weight of graphite as a conductive agent A slurry was prepared by mixing 3 parts by weight of PVdF as a binder in an NMP solution. The obtained slurry was applied to a current collector made of an aluminum foil having a thickness of 15 μm, dried and pressed to prepare a positive electrode having an electrode density of 3.0 g / cm 3 and an electrode width of 49.0 mm.

<Production of negative electrode>
85 parts by weight of lithium titanium oxide (Li4Ti5O12) powder as a negative electrode active material, 5 parts by weight of graphite as a conductive agent, 3 parts by weight of ketjen black as a conductive agent, and 7 parts by weight of PVdF as a binder Were mixed in NMP solution to prepare a slurry. The obtained slurry was applied to a current collector made of an aluminum foil having a thickness of 15 μm, dried and pressed to produce a negative electrode having an electrode density of 2.0 g / cm 3 and an electrode width of 49.5 mm.

<Preparation of separator>
About separator made of PET nonwoven fabric with a width of 50.66 mm and a porosity of 95%, each end 0.36 mm is heated at 85 ° C. until it becomes 0.03 mm, and is placed outside the electrode group having an end width of 0.03 mm and a porosity of 40%. A separator shown in FIG. 4A having a width of 50 mm and a thickness of 50 μm including a portion located inside an electrode group having an inner width of 49.94 mm and a porosity of 95%, sandwiched between the positioned portions, was produced.

<Production of electrode group>
After laminating the positive electrode, the separator, the negative electrode, and the separator in this order, they were wound into a flat shape so that the negative electrode was located in the outermost shell, thereby producing an electrode group.

<Production of nonaqueous electrolyte battery>
The electrode group is housed in a flat container made of aluminum laminate, and a non-aqueous electrolyte prepared by adding 2M LiBF4 as an electrolyte is injected into EMI / BF4, and the flat wound type having the structure shown in FIG. A non-aqueous electrolyte battery was assembled.

  The same as in Example B1 except that the separator end, inside, outermost shell, porosity of curved portion, material, end width Wa and outermost shell of the electrode group were changed as shown in Table 2. Cylindrical wound non-aqueous electrolyte batteries shown in Examples B2 to 21 were assembled.

  In addition, the separator which material differs in an edge part and an inner side joined and produced each material.

  Moreover, in the separator, the porosity of the part located in the curved part of the electrode group and the part located in the outermost shell was appropriately heated and adjusted.

  The obtained non-aqueous electrolyte batteries of Examples B1 to B21 were evaluated for large current characteristics and cycle characteristics as described below.

<Evaluation of large current characteristics>
For a non-aqueous electrolyte battery, a constant current-constant voltage charge was performed up to 2.8 V at 0.2 CmA in an environment of 20 ° C., and then the battery voltage reached 1 V when discharged at 0.2 CmA at 20 ° C. The discharge capacity was 100. Then, after performing constant current-constant voltage charging at 0.2 CmA to 2.8 V in a 20 ° C. environment, the discharge capacity was measured when the battery voltage reached 1 V at 20 ° C. and discharging at 1 CmA. did. The results are also shown in Table 2.

<Cycle characteristic evaluation>
About the nonaqueous electrolyte battery, after charging for 10 hours to 2.8V at 0.2 CmA in a 20 degreeC environment, the charging / discharging cycle which discharges to 1V at 0.2 CmA was given. The cycle life was determined when the discharge capacity dropped to 80% of the discharge capacity at the first cycle. The results are also shown in Table 2 below.

  As shown in Table 2, Examples B2 to B6 are superior in discharge capacity ratio and cycle life as compared to Example B1. Accordingly, it can be understood that the large current characteristic and the cycle characteristic are improved when the ratio of the end width to the total width is 0.1% or more and 40% or less.

  In addition, Examples B9 to B13 are superior in discharge capacity ratio compared to Examples B7 to B8. Therefore, it can be seen that the large current characteristic is further improved when the difference in porosity between the portion located outside and the portion located inside is 5% or more.

  In addition, Examples B18 to B19 are superior in discharge capacity ratio and cycle life to Examples 20 to 21. Therefore, it can be seen that the use of a separator having a low porosity at the outer peripheral edge further improves the large current characteristics and cycle characteristics.

  In addition, Example B18 is superior in discharge capacity ratio to Example B19, and Example B20 is superior to Example B21 in discharge capacity ratio. Therefore, it can be seen that the use of a separator having a low porosity also in the curved portion further improves the large current characteristics.

(Test C)
First, the laminated coin type non-aqueous electrolyte battery shown in Example C1 was manufactured using the manufacturing method shown below.

<Preparation of positive electrode>
Manganese dioxide as the positive electrode active material, Ketjen black as the conductive agent, polytetrafluoroethylene as the binder, and these are uniformly mixed so that the weight ratio is 100: 3: 5: 2, and then pressure molding Thus, a pellet-shaped positive electrode mixture having a thickness of 5 mm and a diameter of 16.0 mm was produced.

<Production of negative electrode>
Lithium metal punched into a thickness of 5 mm and a diameter of 16.0 mm was used as the negative electrode.

<Preparation of separator>
A separator made of a circular PET non-woven fabric is heated at 85 ° C., and is surrounded by a portion located outside the electrode group having an end diameter of 0.001 mm and a porosity of 40%, an inner diameter of 17.999 mm and a porosity of 95%. A separator shown in FIG. 6 having a diameter of 18 mm and a thickness of 50 μm including a portion located inside the electrode group was produced.

<Production of nonaqueous electrolyte battery>
The positive electrode mixture is housed in a positive electrode can made of stainless steel, the negative electrode is housed in a negative electrode can made of stainless steel, a separator is placed between the positive electrode mixture and the negative electrode, and 2M LiBF4 is used as an electrolyte in EMI · BF4. And injecting the prepared non-aqueous electrolyte, leaving it under a reduced pressure of 1 × 10 ⁻³ Torr for 2 hours, and caulking and fixing the positive electrode can and the negative electrode can through an insulating gasket, thereby having the structure shown in FIG. A coin-type non-aqueous electrolyte battery was assembled.

  The coin-type nonaqueous electrolyte batteries shown in Examples C2 to C16 are the same as in Example C1, except that the porosity and material of the end and inside of the separator, and the end width are changed as shown in Table 3. Assembled.

  In addition, the separator which material differs in an edge part and an inner side joined and produced each material.

  The obtained non-aqueous electrolyte batteries of Examples C1 to 16 were evaluated for large current characteristics and cycle characteristics as described below.

<Evaluation of large current characteristics>
For a non-aqueous electrolyte battery, a constant current-constant voltage charge was performed up to 3.2 V at 0.2 CmA in an environment of 20 ° C., and then the battery voltage reached 1 V when discharged at 0.2 CmA at 20 ° C. The discharge capacity was 100. Then, after performing constant current-constant voltage charging up to 3.2V at 0.2CmA in a 20 ° C environment, the discharge capacity was measured when the battery voltage reached 1V when discharged at 1CmA at 20 ° C. did. The results are also shown in Table 3.

<Cycle characteristic evaluation>
About the nonaqueous electrolyte battery, after charging for 10 hours to 0.2V at 0.2 CmA in a 20 degreeC environment, the charging / discharging cycle which discharges to 1V at 0.2 CmA was given. The cycle life was determined when the discharge capacity dropped to 80% of the discharge capacity at the first cycle. The results are also shown in Table 3 below.

  As shown in Table 3, Examples C2 to C6 are superior in discharge capacity ratio and cycle life as compared to Example C1. Therefore, it can be seen that the large current characteristic and the cycle characteristic are further improved when the ratio of the end width to the total width is 0.1% or more and 40% or less.

  In addition, Examples C9 to C13 are more excellent in discharge capacity ratio and cycle life than Examples C7 to C8. Therefore, it is understood that the large current characteristic and the cycle characteristic are further improved when the difference in the porosity between the part located outside and the part located inside is 5% or more.

  A test similar to tests A to C was performed using a low-viscosity liquid non-aqueous electrolyte in which 1 M / L LiPF6 was dissolved in a solvent of EC: MEC (volume ratio 1: 2). The same test was performed using various comparative examples with different edge widths and porosity differences, but all showed the same discharge capacity ratio and cycle life. Therefore, it turns out that this Embodiment exhibits an effect with respect to non-aqueous electrolytes with high viscosity, such as normal temperature molten salt.

(Test D)
Prepare separators made of PE, PP, PET and cellulose materials with a thickness of 100 μm and a porosity of 80%. Each separator is immersed in 0.5M-LiTFSI / EMI / TFSI up to 1 × 10 ⁻³ Torr It was impregnated by allowing to stand under reduced pressure until there were no bubbles. Thereafter, the separator was sandwiched between Pt electrodes, and a silver electrode was further inserted, and the conductivity was measured by a DC quadrupole system. Table 4 shows the measurement results of the conductivity of the room temperature molten salt in each separator.

  As shown in Table 4, the wettability with respect to the room temperature molten salt differs depending on the material of the separator, and this appears in the difference in ion transfer resistance, that is, conductivity. Compared to cellulose, PE and PP have higher conductivity, and PET has higher conductivity than PE and PP. Therefore, it can be seen that PET has high wettability with respect to room temperature molten salt, can reduce ion migration resistance in the separator, and can improve large current characteristics.

  As mentioned above, although embodiment of this invention was described, this invention is not restricted to these, In the category of the summary of the invention as described in a claim, it can change variously. In addition, the present invention can be variously modified without departing from the scope of the invention in the implementation stage. Furthermore, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment.

The partial notch side surface schematic diagram of the nonaqueous electrolyte battery concerning the 1st Embodiment of this invention. The surface schematic diagram of the separator concerning the 1st embodiment of the present invention. The partial notch perspective schematic diagram of the nonaqueous electrolyte battery concerning the 2nd Embodiment of this invention. The surface schematic diagram of the separator concerning the 2nd Embodiment of this invention. The cross-sectional schematic diagram of the nonaqueous electrolyte battery concerning the 3rd Embodiment of this invention. The surface schematic diagram of the separator concerning the 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Container 12 Insulator 13 Electrode group 14 Positive electrode 15 Separator 15a The part 15b located outside the electrode group 15b The part located inside the electrode group 16 Negative electrode 17 Insulating paper 18 Insulating sealing plate 19 Positive electrode terminal 110 Positive electrode lead 21 Container 23 Electrode group 24 Positive electrode 25 Separator 25a Site 25b located outside electrode group Site 25b located inside electrode group 26 Negative electrode 29 Positive electrode terminal 210 Negative electrode terminal 31 Container 32 Insulating gasket 34 Positive electrode 35 Separator 35a Site 35b located outside electrode group Electrode Site 36 located inside group 36 Negative electrode 39 Positive electrode lead 310 Negative electrode sealing plate

Claims (7)

A container,
A non-aqueous electrolyte filled in the container and containing a room temperature molten salt;
A positive electrode housed in the container;
A negative electrode housed in the container;
Wherein the negative electrode and the site of the inner wherein Ru sandwiched between a positive electrode, a separator and an outer portion located outside the region of the inner, the separator is the nonaqueous electrolyte is filled, and part of the outer Has a low porosity as compared with the inner portion. The positive electrode, the negative electrode, and the separator form a wound electrode group,
The non-aqueous electrolyte battery according to claim 1, wherein the outer portion is formed at an end portion that sandwiches the inner portion in a short direction of the separator. The non-aqueous electrolyte battery according to claim 2, wherein the outer portion is formed at an outer peripheral end in a longitudinal direction of the separator. 4. The nonaqueous electrolyte battery according to claim 1, wherein a width of the outer portion is 0.1% or more and 40% or less as compared with a total width of the separator. 5. The difference in porosity between the outer portion and the inner portion is 5% or more, and the porosity of the inner portion is 8% or more and 97% or less. The nonaqueous electrolyte battery according to one item. The non-aqueous electrolyte battery according to any one of claims 1 to 5, wherein the material of the inner portion is polyethylene terephthalate. The cation of the room temperature molten salt is at least one selected from imidazolium ion, tetraalkylammonium ion, alkylpyridinium ion and alkylpiperidinium ion, and the anion of the room temperature molten salt is BF ₄ ⁻ , B (OOC—COO). ₂ ⁻ , PF ₆ −, CF ₃ SO ₃ ⁻ , CF ₃ (CF ₂ ) ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (CF ₃ CF ₂ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) (CF ₃ CF ₂ SO ₂ ) N ⁻ , (CF ₃ SO ₂ ) (CF ₃ CF ₂ CF ₂ SO ₂ ) N ⁻ , (CF ₃ SO ₂ ) (CF ₃ CF ₂ CF ₂ CFSO ₂ ) N ^{_{-, (CF 3 SO 2)}} (CF 3 CF 2 (CF 3) CFSO 2) N -, (NC) 2 N -, CF 3 CO 2 -, (CF 3 SO 2) 3 C - at least one selected from The features of claims 1 to 6 The nonaqueous electrolyte battery according to any one of the above.

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