Battery

Abstract

Provided is a battery including a positive electrode, a negative electrode disposed apart from the positive electrode, a separator sandwiched between the positive electrode and the negative electrode, and an electrolyte. The electrolyte may contain a nitrate, alkaline earth metal salt, or alkali metal salt at least including lithium nitrate and being in the amount of 0.1% to 50% with respect to the total mass of the electrolyte, and 1% to 40% of hydrofluoroether with respect to the total mass of the electrolyte. The electrolyte may contain 10% to 70% of fluoroethylene carbonate with respect to the total mass of the electrolyte.

Description

battery

[0001] The present invention relates to a battery.

[0002] Patent Document 1 discloses an electrolyte solution for lithium metal batteries containing a lithium salt. Patent Document 2 discloses an electrolyte solution for lithium metal batteries containing a fluorinated diether. Patent Document 3 discloses a lithium ion battery containing a fluorinated ether. [Prior art documents] [Patent documents] [Patent document 1] JP 2023-149505 A [Patent document 2] JP 2023-553478 A [Patent document 3] JP 2023-522378 A General disclosure

[0003] (Means for Solving the Problems) A first aspect of the present invention provides a battery comprising a positive electrode, a negative electrode disposed spaced apart from the positive electrode, a separator sandwiched between the positive electrode and the negative electrode, and an electrolyte solution, wherein the electrolyte solution may contain at least lithium nitrate and an alkali metal salt, an alkaline earth metal salt, or a nitrate in an amount of 0.1% to 50% relative to the total mass of the electrolyte solution, and 1% to 40% relative to the total mass of the electrolyte solution of a hydrofluoroether.

[0004] In the battery, the electrolyte may contain 10% or more and 70% or less of fluoroethylene carbonate based on the total mass of the electrolyte.

[0005] In any of the batteries described above, the electrolytic solution may contain an electrolyte in an amount of 7% to 30% by weight, based on the total weight of the electrolytic solution, and a non-aqueous solvent in an amount of 10% to 90% by weight, based on the total weight of the electrolytic solution.

[0006] In any of the batteries described above, the alkali metal salt, alkaline earth metal salt, or nitrate may include at least one selected from potassium nitrate, sodium nitrate, magnesium nitrate, cesium nitrate, calcium nitrate, zinc nitrate, silver nitrate, lead nitrate, and copper nitrate.

[0007] In any of the above batteries, the hydrofluoroether is 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, 3,3,4,4-tetrafluorotetrahydrofuran, 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)pentane, hexafluoroisopropyl methyl ether, or methyl nonafluorobutyl ether. , methyl 2,2,3,3,3-pentafluoropropyl ether, 1,1,2,3,3,3-hexafluoropropyl methyl ether, 1,1,2,3,3,3-hexafluoropropyl ethyl ether, 1,1,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether, bis(2,2,2-trifluoroethyl)ether, methyl 1,1,2,2-tetrafluoroethyl ether, or ethyl 1,1,2,2-tetrafluoroethyl ether.

[0008] In any of the above batteries, the electrolyte is selected from the group consisting of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, and LiBF ４ , LiClO ４ , LiC(CF ３ SO ２ ) ３ , LiCH(CF ３ SO ２ ) ２ , LiF, LiCl, LiBr, LiI, Li ２ S, LiB １２ F １２ , LiAsF ６ , LiFSO ３ , Li ２ SiF ６ , LiCF ３ CO ２ , LiCH ３ CO ２ , LiCF ３ SO ３ , LiC ４ F ９ SO ３ , LiCF３ CF ２ SO ３ 、LiCF ３ (CF) ２ ) ７ SO ３ 、LiCF ３ CF ２ (CF) ３ ) ２ Carbon, Li (CF) ３ SO ２ ) ２ H、LinO ３ 、LiN(CN) ２ 、Lii}(FSO) ２ ) ２ 、Lii}(F ２ SO ２ ) ２ 、Lii}(FF ３ SO ２ ) ２ 、LiN(C ２ F ５ SO ２ ) ２ 、Li+P(CF ３ ) ６ 、Li+PF(FF ３ ) ５ 、Li)PF ２ (CF) ３ ) ４ 、Li)PF ３ (CF) ３ ) ３ 、Li)PF ４ (CF) ３ ) ２ 、Li)PF ４ (C ２ F ５ ) ２ 、Li)PF ４ (CF) ３ SO ２ ) ２ 、Li)PF ４ (C ２ F ５ SO ２ ) ２ 、Liida ２ C ２ O ４ 、LiBC ４ O ８ 、Liida ２ (CF) ３ ) ２ 、Liida２ (C ２ F ５ ) ２ , LiBF ２ (CF ３ SO ２ ) ２ , LiBF ２ (C ２ F ５ SO ２ ) ２ , LiSbF ６ , LiAlO ４ , LiAlF ４ , LiSCN or LiAlCl ４ It may include at least one selected from:

[0009] In any of the batteries described above, the nonaqueous solvent may contain at least one selected from a saturated acyclic diether (excluding 1,2-dimethoxyethane) or cyclic ether having 6 or less carbon atoms, a cyclic carbonate or saturated acyclic carbonate having 5 or less carbon atoms, difluoroethylene carbonate, and a cyclic ester or saturated acyclic ester having 5 or less carbon atoms.

[0010] In any of the batteries described above, the nonaqueous solvent may include at least one selected from 1,2-dimethoxyethane, 1,3,5-trioxane, diethylene glycol dimethyl ether, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, difluoroethylene carbonate, γ-butyrolactone, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, and ethyl propionate.

[0011] In any of the batteries described above, the electrolyte solution may contain at least one additive in an amount of 0.01% to 15% based on the total mass of the electrolyte solution.

[0012] In any of the batteries described above, the additive may include at least one selected from tetravinylsilane, vinylene carbonate, chloroethylene carbonate, lithium difluoroacetate, fluorobenzene, ortho-fluorotoluene, meta-fluorotoluene, para-fluorotoluene, ethylbenzene, adiponitrile, succinonitrile, 1,3,6-hexanetricyanide, 1,3-propane sultone, ethylene sulfite, lithium difluorooxalatoborate, and lithium bisoxalatoborate.

[0013] In any of the above batteries, the total mass of the hydrofluoroether may be 5% or more and 20% or less with respect to the total mass of the electrolyte solution.

[0014] In any of the batteries described above, the hydrofluoroether may contain 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether in an amount of 5% to 20% based on the total mass of the electrolyte solution.

[0015] In any of the above batteries, the electrolyte may contain 20% or more and 55% or less of fluoroethylene carbonate based on the total mass of the electrolyte.

[0016] In a second aspect of the present invention, there is provided a battery comprising a positive electrode, a negative electrode spaced apart from the positive electrode, a separator sandwiched between the positive electrode and the negative electrode, an electrolyte, and an alkali metal salt, alkaline earth metal salt, or nitrate containing at least lithium nitrate in an amount of 0.1% to 40% by volume of the separator. The electrolyte may contain 1% to 40% by volume of a hydrofluoroether based on the total mass of the electrolyte.

[0017] In the battery, the alkali metal salt, alkaline earth metal salt, or nitrate may be 1% or more and 30% or less by volume of the separator. The hydrofluoroether may include 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether in an amount of 5% or more and 20% or less by total mass of the electrolyte. The electrolyte may include 20% or more and 55% or less by total mass of the electrolyte.

[0018] The above summary of the invention does not list all of the features of the present invention, and subcombinations of these features may also be inventions.

[0019] 1A and 1B schematically show an example of the internal structure of a storage battery 100. 1A schematically shows an example of a positive electrode 120. 1A schematically shows an example of a negative electrode 140. 1A schematically shows an example of an electrode structure 410. 1A schematically shows an example of a manufacturing method for a storage battery 100. 1A schematically shows an example of an electrode structure 610. 1A schematically shows an example of an electrode structure 710. 1A schematically shows an example of a unit 812.

[0020] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention. Not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention. Furthermore, the embodiments will be described with reference to the drawings, but in the description of the drawings, the same reference numerals may be used to designate the same or similar parts, and redundant description may be omitted.

[0021] In this specification, when a numerical range is expressed as "A to B," the expression means A or more and B or less. Furthermore, "substituted or unsubstituted" means "substituted with any substituent, or not substituted with any substituent." The type of the above-mentioned substituent is not particularly limited unless otherwise specified in the specification. Furthermore, the number of the above-mentioned substituents is not particularly limited unless otherwise specified in the specification.

[0022] (Outline of Storage Battery 100) Fig. 1 schematically illustrates an example of the internal structure of the storage battery 100. Fig. 1 may be an example of a cross-sectional view of the storage battery 100. In this example, the storage battery 100 is a prismatic secondary battery, and details of the storage battery 100 will be described.

[0023] In this example, the storage battery 100 stores electrical energy and supplies the stored electrical energy to the outside. A power source can be created by connecting a plurality of storage batteries 100 in series and / or parallel.

[0024] The type of storage battery 100 is not particularly limited, but the storage battery 100 may be an insertion-type storage battery or a reservoir-type storage battery. The storage battery 100 may also be a metal-negative electrode battery that uses a metal as the negative electrode active material. This results in a storage battery 100 with a high energy density. Examples of metal-negative electrode batteries include alkali metal-negative electrode batteries, which are secondary batteries that use an alkali metal as the negative electrode material, and magnesium metal batteries, which are secondary batteries that use magnesium metal (sometimes referred to as metallic magnesium) as the negative electrode material. Examples of alkali metal-negative electrode batteries include lithium metal batteries, which are secondary batteries that use lithium metal (sometimes referred to as metallic lithium) as the negative electrode material.

[0025] (Overview of Each Part of Storage Battery 100) In this example, the storage battery 100 includes an electrode structure 110. In this example, the electrode structure 110 includes a positive electrode 120, a separator 130, and a negative electrode 140. As shown in Fig. 1 , in this example, the electrode structure 110 includes a laminate formed by stacking at least the negative electrode 140, the first separator 130, the positive electrode 120, and the second separator 130 in this order.

[0026] In this example, the electrode structure 110 will be described in detail using as an example a case where one of the outermost layers of the electrode structure 110 is a positive electrode 120 and the other of the outermost layers of the electrode structure 110 is a negative electrode 140. However, the structure of the electrode structure 110 is not limited to this example. The electrode structure 110 may have various structures in which the positive electrode 120 and the negative electrode 140 are arranged to face each other with a separator 130 interposed therebetween. For example, in a modified example, both of the outermost layers of the electrode structure 110 may be positive electrodes 120, or both of the outermost layers of the electrode structure 110 may be negative electrodes 140.

[0027] In this example, a positive electrode tab 122 is provided at the end of the positive electrode 120. In this example, a negative electrode tab 142 is provided at the end of the negative electrode 140. In this example, the storage battery 100 also includes an electrolyte 150, a battery case 160, a positive electrode terminal 162, a negative electrode terminal 164, a positive electrode lead 172, and a negative electrode lead 174.

[0028] In this example, the electrode structure 110 has a structure in which positive electrodes 120 and negative electrodes 140 are alternately stacked with separators 130 interposed therebetween. The separators 130 may be formed by folding a single sheet, or may be formed from multiple sheets.

[0029] In the storage battery 100 according to this example, the positive electrode 120 and the negative electrode 140 are arranged such that the positive electrode active material of the positive electrode 120 and the negative electrode active material of the negative electrode 140 face each other across the separator 130. The negative electrode 140 has a function of directly transferring charge in conjunction with the reaction of the positive electrode active material, for example. However, depending on the type of battery, a third type of electrode may be provided in addition to the positive electrode and negative electrode.

[0030] For example, depending on the type of lithium-ion battery, a lithium electrode having a lithium metal foil may be disposed separately from the negative electrode. The lithium-ion battery described above includes, for example, an electrode stack unit including a stack structure of positive electrode / first separator / negative electrode / first separator / positive electrode / second separator / lithium electrode. In this case, the positive electrode and lithium electrode are disposed such that the current collector of the positive electrode and the lithium metal foil of the lithium electrode face each other with the second separator interposed therebetween. Meanwhile, the positive electrode and negative electrode are disposed such that the positive electrode active material of the positive electrode and the negative electrode active material of the negative electrode face each other with the separator interposed therebetween. In this respect, the lithium electrode and the negative electrode can be distinguished.

[0031] (Positive Electrode) In this example, the positive electrode 120 is electrically connected to the positive electrode terminal 162 via a positive electrode tab 122 and a positive electrode lead 172. In this example, the positive electrode tab 122 is disposed so as to protrude from the positive electrode 120. The details of the positive electrode 120 and the positive electrode tab 122 will be described later.

[0032] (Separator) In this example, the separator 130 is disposed between the positive electrode 120 and the negative electrode 140 to isolate the positive electrode 120 and the negative electrode 140. This prevents the positive electrode 120 and the negative electrode 140 from coming into direct contact with each other and causing a short circuit. The separator 130 ensures ionic conductivity between the positive electrode 120 and the negative electrode 140, for example, by retaining an electrolyte solution.

[0033] The separator 130 includes, for example, one or more polymeric materials, one or more inorganic materials, and a combination thereof. Examples of materials for the separator 130 include cellulose, polyethylene terephthalate (PET), polyolefin, glass, and composites of these. Examples of polyolefin include polyethylene, polypropylene, and ethylene-propylene copolymer.

[0034] Examples of the shape of the separator 130 include a microporous film, a nonwoven fabric, and a filter. The separator 130 may be a laminate of these films. The thickness of the separator 130 is not particularly limited, but is preferably 10 to 50 μm. The aperture ratio of the separator 130 is not particularly limited, but is preferably 30 to 70%.

[0035] The separator 130 may include multiple layers, at least two of which may be made of different materials, structures, and / or physical properties.

[0036] The separator 130 may include at least one layer of polyolefin film. The polyolefin film may be a non-stretched film or a stretched film. The polyolefin film may be a porous stretched film. The stretched film may be a uniaxially stretched film or a biaxially stretched film.

[0037] The method for producing a polyolefin porous film that can be used as the separator 130 is not particularly limited, but examples of the method for producing the porous film include a dry method and a wet method. In the dry method, a resin material is first heated. This melts the resin material. Next, the melted resin material is formed into a film. Next, the film-formed resin is subjected to a heat treatment, and then the resin is stretched under specific conditions. This produces a film-like resin with pores formed therein.

[0038] According to the wet method, first, a mixture of a resin material and a plasticizer is heated. This melts the mixture. The mixture may contain an inorganic filler. Next, the melted mixture is formed into a film. Next, the film-formed mixture is stretched under specific conditions. Thereafter, a process for extracting the plasticizer and a washing process are carried out. This produces a film-like resin having pores formed therein.

[0039] (Negative Electrode) The negative electrode 140 is disposed apart from the positive electrode 120. In this example, the negative electrode 140 is electrically connected to the negative electrode terminal 164 via the negative electrode tab 142 and the negative electrode lead 174. In this example, the negative electrode tab 142 is disposed so as to protrude from the negative electrode 140.

[0040] When the storage battery 100 is a lithium metal battery using lithium metal as the negative electrode active material, lithium metal may dissolve and precipitate from the negative electrode 140. When the storage battery 100 is a lithium metal battery using lithium metal as the negative electrode active material, the electrode potential of the negative electrode 140 based on Li / Li+ may be 0.5 V or less. The electrode potential may be 0.2 V or less, and is preferably 0.1 V or less. Details of the negative electrode 140 and the negative electrode tab 142 will be described later.

[0041] (Electrolyte) The electrolyte 150 forms an electrolytic film on the negative electrode 140 when the storage battery 100 is being charged. The electrolyte 150 realizes ionic conduction between the positive electrode active material and the negative electrode active material via the electrolyte contained in the electrolyte 150. A known organic electrolyte can be used as the electrolyte 150. The electrolyte 150 includes, for example, a metal salt as an electrolyte and a polar solvent. The polar solvent may be an organic solvent.

[0042] The metal salt may be a salt of a carrier metal of the storage battery 100. The carrier metal may be an alkali metal. Examples of the metal salt include lithium salt, sodium salt, magnesium salt, aluminum salt, and zinc salt. As the metal salt, a single type of metal salt may be used, or multiple types of metal salts may be used in combination.

[0043] The organic solvent is not particularly limited as long as it dissolves the metal salt and is unlikely to cause side reactions such as decomposition within the voltage range used in the battery. A single type of organic solvent may be used, or multiple organic solvents may be used in combination.

[0044] The electrolyte 150 contains at least nitrates including lithium nitrate. The electrolyte 150 may contain an alkali metal salt or an alkaline earth metal salt. The amount of the alkali metal salt, alkaline earth metal salt, or nitrate contained in the electrolyte 150 may be 0.1% or more and 50% or less based on the total mass of the electrolyte 150. The amount of salt contained in the electrolytic solution 150 may be the content of lithium nitrate, or the total amount of a plurality of salts selected from the group consisting of nitrates such as lithium nitrate, potassium nitrate, sodium nitrate, magnesium nitrate, cesium nitrate, calcium nitrate, zinc nitrate, silver nitrate, lead nitrate, and copper nitrate, at least one alkali metal salt selected from the group consisting of fluorides, chlorides, bromides, iodides, nitrates, nitrites, borates, fluoroborates, phosphates, fluorophosphates, sulfates, and fluorosulfates of alkali metals, and at least one alkaline earth metal salt selected from the group consisting of fluorides, chlorides, bromides, iodides, nitrates, nitrites, borates, fluoroborates, phosphates, fluorophosphates, sulfates, and fluorosulfates of alkaline earth metals. The content of the alkali metal salt, alkaline earth metal salt, or nitrate is preferably 0.5% or more and 40% or less of the total mass of the electrolytic solution 150. The content of the alkali metal salt, alkaline earth metal salt, or nitrate is more preferably 1% or more and 30% or less with respect to the total mass of the electrolyte solution 150. By making the content of the alkali metal salt, alkaline earth metal salt, or nitrate 0.1% or more of the total mass of the electrolyte solution 150, a good electrolytic film can be formed on the surface of the negative electrode 140. By making the content of the alkali metal salt, alkaline earth metal salt, or nitrate 50% or less of the total mass of the electrolyte solution 150, the viscosity of the electrolyte solution 150 can be reduced, the diffusion of ions in the electrolyte solution 150 is not hindered, and the cycle characteristics of the storage battery 100 can be improved.

[0045] The alkali metal salt, alkaline earth metal salt, or nitrate does not have to be completely dissolved in the electrolyte solution 150. The alkali metal salt, alkaline earth metal salt, or nitrate may be contained in a suspended state in the electrolyte solution 150. The alkali metal salt, alkaline earth metal salt, or nitrate may be contained inside the battery case 160 of the storage battery 100 in a form supported on a support or the like described below, or may be contained inside the battery case 160 in the form of a powder of the alkali metal salt, alkaline earth metal salt, or nitrate. When the alkali metal salt, alkaline earth metal salt, or nitrate is contained as a solid, it is preferably contained between the negative electrode 140 and the separator 130.

[0046] The nitrate may be an alkali metal nitrate, and may include at least one selected from potassium nitrate, sodium nitrate, magnesium nitrate, cesium nitrate, calcium nitrate, zinc nitrate, silver nitrate, lead nitrate, and copper nitrate.

[0047] The electrolyte solution 150 contains 1% or more and 40% or less of hydrofluoroether (HFE) relative to the total mass of the electrolyte solution 150. The total mass of the hydrofluoroether is preferably 3% or more and 30% or less relative to the total mass of the electrolyte solution 150. The total mass of the hydrofluoroether is more preferably 5% or more and 20% or less relative to the total mass of the electrolyte solution 150. By making the total mass of the hydrofluoroether 150 1% or more of the total mass of the electrolyte solution 150, the flash point of the electrolyte solution 150 can be increased and the safety of the storage battery 100 can be improved. By making the total mass of the hydrofluoroether 150 40% or less of the total mass of the electrolyte solution 150, the cycle characteristics of the storage battery 100 can be improved without causing phase separation of the electrolyte solution 150.

[0048] Hydrofluoroethers are ether compounds having at least one fluorine-substituted hydrocarbon group. Hydrofluoroethers may be cyclic ethers or acyclic ethers. Examples of hydrofluoroethers include 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE), 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether (OTE), 3,3,4,4-tetrafluorotetrahydrofuran (FTHF), 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)pentane (HFE-7300), hexafluoroisopropyl methyl ether, and methyl nonafluorobutyl ether. The electrolytic solution 150 may contain at least one selected from the group consisting of 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether, bis(2,2,2-trifluoroethyl)ether, methyl 1,1,2,2-tetrafluoroethyl ether, and ethyl 1,1,2,2-tetrafluoroethyl ether. The hydrofluoroether preferably contains 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE) in an amount of 5% or more and 20% or less based on the total mass of the electrolytic solution 150.

[0049] The electrolyte solution 150 may contain 10% or more and 70% or less of fluoroethylene carbonate (FEC) based on the total mass of the electrolyte solution 150. The fluoroethylene carbonate content is preferably 15% or more and 60% or less based on the total mass of the electrolyte solution 150. The fluoroethylene carbonate content is more preferably 20% or more and 55% or less based on the total mass of the electrolyte solution 150. By setting the fluoroethylene carbonate content to 10% or more, a good electrolytic coating can be formed on the surface of the negative electrode 140. By setting the fluoroethylene carbonate content to 70% or less, the viscosity of the electrolyte solution 150 can be reduced, the diffusion of ions in the electrolyte solution 150 is not hindered, and the cycle characteristics of the storage battery 100 can be improved.

[0050] The electrolyte solution 150 contains 7% or more and 30% or less of electrolytes relative to the total mass of the electrolyte solution 150. The lower limit of the total mass of the electrolytes contained in the electrolyte solution 150 is not particularly limited, but is preferably 8% or more, and more preferably 9% or more, relative to the total mass of the electrolyte solution 150. The upper limit of the total mass of the electrolytes contained in the electrolyte solution 150 is not particularly limited, but is preferably 20% or less, and more preferably 15% or less, relative to the total mass of the electrolyte solution 150. By making the electrolyte content 7% or more of the total mass of the electrolyte solution 150, the ionic conductivity of the electrolyte solution 150 can be improved, and the cycle characteristics of the storage battery 100 can be improved. By making the electrolyte content 30% or less of the total mass of the electrolyte solution 150, the viscosity of the electrolyte solution 150 can be reduced, and the diffusion of ions in the electrolyte solution 150 can be prevented, thereby improving the cycle characteristics of the storage battery 100.

[0051] The electrolyte acts as a medium for transporting ions involved in the electrochemical reaction in the secondary battery. The electrolyte is lithium hexafluorophosphate (LiPF ６ ), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), LiBF ４ , LiClO ４ , LiC(CF ３ SO ２ ) ３ , LiCH(CF ３ SO ２ ) ２、five、five、five、five、または ２ This is a nice place to stay with 11. 1.0 １２ 9 １２ 、DYS9 ６ 、DIS ３ 、4) ２ 69 ６ 、49 ３ 10. The ２ 、44 ３ 10. The ２ 、49 ３ 19 ３ 、(4) ４ 9 ９ 19 ３ 、49 ３ 9. The ２ 19 ３ 、49 ３ (40) ２ ) ７ 19 ３ 、49 ３ 9. The ２ (40) ３ ) ２ 20、4(10). ３ 19 ２ ) ２ NU、99 ３ 、19(9) ２ 、N9(S3 ２ ) ２ 、99(5). ２ 19 ２ ) ２ 、9(40). ３ 19 ２ ) ２ 、19(4). ２ 9 ５ 19 ２ ) ２ 、40(40) ３ ) ６ 、400(40) ３ ) ５ 、1000 ２ (40) ３ ) ４ 、1000 ３ (40) ３ ) ３ 、1000 ４ (40) ３ ) ２ 、1000 ４ (4)２ F ５ ) ２ , LiPF ４ (CF ３ SO ２ ) ２ , LiPF ４ (C ２ F ５ SO ２ ) ２ , LiBF ２ C ２ O ４ , LiBC ４ O ８ , LiBF ２ (CF ３ ) ２ , LiBF ２ (C ２ F ５ ) ２ , LiBF ２ (CF ３ SO ２ ) ２ , LiBF ２ (C ２ F ５ SO ２ ) ２ , LiSbF ６ , LiAlO ４ , LiAlF ４ , LiSCN or LiAlCl ４ It may include the following:

[0052] The electrolyte solution 150 contains a non-aqueous solvent in an amount of 10% or more and 90% or less, based on the total mass of the electrolyte solution 150. The content of the non-aqueous solvent is preferably 20% or more and 80% or less, based on the total mass of the electrolyte solution 150. The content of the non-aqueous solvent is more preferably 30% or more and 70% or less, based on the total mass of the electrolyte solution 150. By making the content of the non-aqueous solvent 150 10% or more of the total mass of the electrolyte solution 150, the viscosity of the electrolyte solution 150 can be reduced, promoting the diffusion of ions in the electrolyte solution 150 and improving the cycle characteristics of the storage battery 100. By making the content of the non-aqueous solvent 90% or less of the total mass of the electrolyte solution 150, the electrolyte concentration in the electrolyte solution 150 can be increased, improving ionic conductivity and improving the cycle characteristics of the storage battery 100.

[0053] The non-aqueous solvent is an ether-based, diether-based, or ester-based organic solvent capable of solvating the nitrate salt. The non-aqueous solvent may include at least one selected from saturated acyclic diethers or cyclic ethers having 6 or fewer carbon atoms (excluding 1,2-dimethoxyethane), cyclic carbonates or saturated acyclic carbonates having 5 or fewer carbon atoms, difluoroethylene carbonate, and cyclic esters or saturated acyclic esters having 5 or fewer carbon atoms. The non-aqueous solvent may include at least one selected from 1,3,5-trioxane, diethylene glycol dimethyl ether, dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate, ethylene carbonate (EC), propylene carbonate, difluoroethylene carbonate, γ-butyrolactone, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, and ethyl propionate. The non-aqueous solvent may include 1,2-dimethoxyethane.

[0054] The electrolyte solution 150 contains at least one additive in an amount of 0.01% to 15% by weight of the total mass of the electrolyte solution. The additive may include at least one selected from tetravinylsilane, vinylene carbonate, chloroethylene carbonate, lithium difluoroacetate, fluorobenzene, ortho-fluorotoluene, meta-fluorotoluene, para-fluorotoluene, ethylbenzene, adiponitrile, succinonitrile, 1,3,6-hexanetricyanide, 1,3-propane sultone, ethylene sulfite, lithium difluorooxalatoborate, and lithium bis(oxalato)borate. By including the additive in the electrolyte solution 150, the cycle characteristics of the storage battery 100 can be further improved.

[0055] (Housing) The battery case 160 contains the electrode structure 110 and the electrolyte solution 150. The electrode structure 110 and the electrolyte solution 150 may be sealed.

[0056] (Electrochemical Performance of Storage Battery 100) The electrochemical performance of the storage battery 100 is affected by the quality of the electrolytic film formed on the negative electrode 140 during charging and discharging of the storage battery 100. In order to improve the cycle characteristics of the storage battery 100, it is desirable to form a high-quality electrolytic film that is rich in lithium ion conductivity and electrical conductivity.

[0057] The present inventors have found that adding hydrofluoroether (HFE) to an electrolyte solution containing lithium nitrate can provide a storage battery 100 with excellent cycle characteristics. In particular, they have found that adding HFE improves cycle characteristics even when lithium nitrate is not completely dissolved in the electrolyte solution and exists in a suspended state or is contained as a solid powder inside the battery case 160.

[0058] Conventionally, when adding lithium nitrate to an electrolyte solution, it is preferable to include a non-fluorinated ether solvent such as 1,2-dimethoxyethane (DME) in order to improve solubility. However, such non-fluorinated ethers are prone to oxidation on the positive electrode side of the battery, resulting in a problem of liquid depletion. In this embodiment, since lithium nitrate does not need to be completely dissolved in the electrolyte solution, there is no need to use a non-fluorinated ether solvent such as DME. This can prevent liquid depletion in the storage battery 100.

[0059] The present inventors have found that a storage battery 100 with particularly excellent cycle characteristics can be obtained when the electrolyte solution contains fluoroethylene carbonate (FEC) in addition to lithium nitrate and HFE. Patent Documents 1 to 3, which are listed in the prior art literature, describe the effects of combining lithium nitrate with either HFE or FEC alone, but do not describe the improvement in cycle characteristics that can be achieved by adding FEC to an electrolyte solution containing lithium nitrate and HFE. The present inventors have found that the cycle characteristics of the storage battery 100 can be significantly improved by combining lithium nitrate, HFE, and FEC, which alone do not provide sufficient cycle characteristics.

[0060] The storage battery 100 may be an example of a battery. The electrode structure 110 may be an example of a battery structure. The positive electrode 120 may be an example of a positive electrode. The negative electrode 140 may be an example of an electrode, a negative electrode, a first negative electrode, a second negative electrode, or a battery structure. The separator 130 may be an example of a first separator or a second separator. The electrolytic solution 150 may be an example of an electrolyte. The battery case 160 may be an example of a housing.

[0061] (Another embodiment) In this example, an example of the storage battery 100 has been described using a case where the storage battery 100 is a prismatic battery. However, the storage battery 100 is not limited to this example. In a modified example, the storage battery 100 may be a cylindrical battery, a laminated battery (sometimes referred to as a pouch battery), or a coin battery.

[0062] In this example, an example of the electrode structure 110 has been described, taking as an example a case where the electrode structure 110 has a stacked structure in which positive electrodes and negative electrodes are alternately stacked with separators interposed therebetween. However, the electrode structure 110 is not limited to this example. In a modified example, the electrode structure 110 may have a wound type (sometimes referred to as a jelly roll type) structure in which a positive electrode, a separator, and a negative electrode are stacked and wound into a roll.

[0063] (Positive Electrode) Figure 2 shows a schematic diagram of an example of the positive electrode 120. In this example, the positive electrode 120 includes a positive electrode current collector 220 and a positive electrode active material layer 240. The positive electrode 120 may include a laminate in which the positive electrode current collector 220 and the positive electrode active material layer 240 are laminated in this order. In this example, the positive electrode current collector 220 has a first main surface 222, a second main surface 224, and a side surface 226 connecting the first main surface 222 and the second main surface 224.

[0064] In this example, for the purpose of simplifying the explanation, the details of the positive electrode 120 will be explained using as an example a case where the positive electrode active material layer 240 is disposed on one surface of the positive electrode current collector 220. However, the positive electrode 120 is not limited to this example. In a modified example, the positive electrode active material layer 240 may be disposed on both surfaces of the positive electrode current collector 220.

[0065] In this example, a region where the positive electrode active material layer 240 is not formed is disposed at one end of the positive electrode current collector 220. This region is used as the positive electrode tab 122. In a modified example, a conductive terminal member may be disposed on at least a portion of the positive electrode tab 122. The material of the terminal member is not particularly limited, but examples include nickel, iron, copper, and aluminum.

[0066] In this example, the positive electrode current collector 220 holds the positive electrode active material layer 240. The material of the positive electrode current collector 220 is not particularly limited as long as it is an electron conductor that is chemically stable in the storage battery 100. Examples of materials for the positive electrode current collector 220 include nickel, copper, iron, aluminum, stainless steel, nickel, titanium, and alloys thereof. Examples of the shape of the positive electrode current collector 220 include foil, mesh, punched metal, and expanded metal. The thickness of the positive electrode current collector 220 is not particularly limited, but is preferably 5 to 200 μm. The thickness of the positive electrode current collector 220 may be 6 to 20 μm.

[0067] In this example, the positive electrode active material layer 240 is formed on at least one surface of the positive electrode current collector 220. The thickness of the positive electrode active material layer 240 may be 1 to 300 μm, or may be 2 to 200 μm, per surface of the positive electrode current collector 220. The positive electrode active material layer 240 includes, for example, a positive electrode active material and a binding agent (sometimes referred to as a binder). The positive electrode active material layer 240 may include a conductive additive.

[0068] In one embodiment, the positive electrode active material layer 240 is formed by applying a paste containing the materials constituting the positive electrode active material layer 240 and an organic solvent to at least one surface of the positive electrode current collector 220, and then drying the paste. The type of the organic solvent is not particularly limited, but an example of the organic solvent is N-methylpyrrolidone (NMP). In a modified example, the positive electrode active material layer 240 is formed by mixing the materials constituting the positive electrode active material layer 240, forming the mixture into a sheet, and pressing the sheet-like mixture onto at least one surface of the positive electrode current collector 220.

[0069] The positive electrode active material is, for example, a material that can insert and remove metal ions that serve as charge carriers and has a higher potential than the negative electrode active material. For example, when the storage battery 100 is a lithium battery, an insertion-type transition metal oxide such as a lithium layered oxide, an olivine, or a spinel is used as the positive electrode active material. Examples of lithium batteries include lithium ion batteries and lithium metal batteries.

[0070] A high-capacity conversion-type positive electrode active material may be used as the positive electrode active material. Examples of high-capacity conversion-type positive electrode active materials include sulfur, sulfur compounds, iron fluoride, and transition metal oxides. The conversion-type positive electrode active material does not contain a metal that serves as a charge carrier in the initial state. Therefore, when a positive electrode containing the conversion-type positive electrode active material is combined with a metal negative electrode, the energy density of the storage battery 100 is significantly improved.

[0071] In this example, the binder binds the materials (e.g., the positive electrode active material, the conductive additive, etc.) that make up the positive electrode active material layer 240 and maintains the electrode shape of the positive electrode 120. The type of binder is not particularly limited as long as it is chemically stable in the storage battery 100. As the binder, a thermoplastic resin or a thermosetting resin may be used. Examples of binders include polyethylene, polypropylene, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylic acid, and styrene butadiene rubber.

[0072] In this example, the conductive additive reduces the resistance of the positive electrode 120. The conductive additive may be any additive that is chemically stable in the storage battery 100 and has the desired electronic conductivity, and its type is not particularly limited. An inorganic material or an organic material may be used as the conductive additive. Examples of the conductive additive include carbon materials. Examples of the carbon material include graphite, carbon black (e.g., acetylene black, ketjen black, etc.), coke, amorphous carbon, carbon fiber, carbon nanotubes, and graphene. These conductive additives may be used alone, or two or more types of conductive additives may be used in combination.

[0073] (Negative electrode) The negative electrode 140 will be described in detail with reference to Fig. 3. Fig. 3 schematically shows an example of the negative electrode 140. Fig. 3 schematically shows an example of a cross section of the negative electrode 140 cut along a plane substantially parallel to the thickness direction or stacking direction (z direction in the drawing) of the negative electrode 140, for example.

[0074] In the embodiment shown in FIG. 3 , the negative electrode 140 includes, for example, a negative electrode current collector 320 and a negative electrode active material layer 340. The negative electrode 140 may include a laminate in which the negative electrode current collector 320 and the negative electrode active material layer 340 are laminated in this order. This allows the positive electrode active material layer 240 of the positive electrode 120 and the negative electrode active material layer 340 of the negative electrode 140 to be separated by at least the separator 130. As a result, an electrode structure 110 having excellent short-circuit resistance, chemical stability, and / or physical stability is obtained. The negative electrode 140 may include another layer between the negative electrode current collector 320 and the negative electrode active material layer 340. The negative electrode 140 may further include a fiber layer laminated on the negative electrode active material layer 340.

[0075] In this example, for the purpose of simplifying the explanation, the details of the anode 140 will be described using as an example a case where the anode active material layer 340 is disposed on one surface of the anode current collector 320. However, the anode 140 is not limited to this example. In a modified example, the anode active material layer 340 may be disposed on both surfaces of the anode current collector 320. In this case, the anode 140 is formed by, for example, stacking the anode active material layer 340, the anode current collector 320, and the anode active material layer 340 in this order.

[0076] In this example, the negative electrode current collector 320 has a first main surface 322, a second main surface 324, and a side surface 326 connecting the first main surface 322 and the second main surface 324. In this example, the negative electrode active material layer 340 has a first main surface 342, a second main surface 344, and a side surface 346 connecting the first main surface 342 and the second main surface 344.

[0077] In this example, the main surface of each layer may be a surface approximately perpendicular to the thickness direction of the negative electrode 140. In each layer, one of the two main surfaces may be a smooth surface (sometimes referred to as a shiny surface or S surface). The other of the two main surfaces may be a rough surface (sometimes referred to as a matte surface or M surface). The side surface of each layer may be a surface extending in the thickness direction of the negative electrode 140.

[0078] For the purpose of simplifying the explanation, in this example, an example of the negative electrode 140 will be described in which the negative electrode current collector 320 and the negative electrode active material layer 340 have a rectangular plate shape or a square pillar shape. However, the shapes of the negative electrode current collector 320 and the negative electrode active material layer 340 are not limited to this example.

[0079] (Negative Electrode Current Collector) In this example, the negative electrode current collector 320 electrically connects the negative electrode lead 174 and the negative electrode active material layer 340. For the negative electrode current collector 320, a material that does not react with lithium or a material that is poorly reactive with lithium is used.

[0080] In one embodiment, the negative electrode current collector 320 is made of one or more metal materials, one or more conductive resins, one or more carbon materials, or a combination thereof. Examples of the metal materials include copper, aluminum, stainless steel, nickel, titanium, and alloys thereof.

[0081] In a modified example, the negative electrode current collector 320 includes a resin support layer and a metal layer disposed on the surface of the support layer. Examples of the resin include polyethylene, polypropylene, polyethylene terephthalate, and polyimide. The metal layer may be a layer made of copper, aluminum, stainless steel, nickel, titanium, or an alloy thereof. The metal layer may include a layer made of copper, aluminum, stainless steel, nickel, titanium, or an alloy thereof. The metal layer may be a foil or a plated layer.

[0082] Examples of the shape of the negative electrode current collector 320 include foil, mesh, punched metal, expanded metal, and combinations thereof. The thickness of the negative electrode current collector 320 is not particularly limited, but may be 5 to 200 μm. The thickness of the negative electrode current collector 320 is preferably 6 to 20 μm.

[0083] (Negative Electrode Active Material Layer) In this example, the negative electrode active material layer 340 is disposed on at least one surface of the negative electrode current collector 320. In this example, the negative electrode active material layer 340 is disposed on the first main surface 322 of the negative electrode current collector 320. The second main surface 344 of the negative electrode active material layer 340 may be in contact with the first main surface 322 of the negative electrode current collector 320.

[0084] In this example, the negative electrode active material layer 340 includes a negative electrode active material. The negative electrode active material layer 340 may be configured with a foil-shaped or film-shaped negative electrode active material. Examples of the negative electrode active material include various metals. The negative electrode active material may include at least one metal selected from the group consisting of alkali metals, magnesium metal, zinc metal, and aluminum metal.

[0085] In one embodiment, the negative electrode active material may be at least one selected from the group consisting of an alkali metal, an alloy containing an alkali metal, and a composite oxide containing an alkali metal. In a variation, the negative electrode active material may be an alkali metal and / or a composite oxide containing an alkali metal. In a further variation, the negative electrode active material may be an alkali metal. The alkali metal may be lithium metal and / or sodium metal. As described above, these negative electrode active materials may have a foil or film shape.

[0086] The alkali metal may be lithium metal. In this case, the storage battery 100 is the above-described lithium metal storage battery, and the electrode potential of the negative electrode 140 based on Li / Li+ is, for example, 0.5 V or less. The electrode potential may be 0.2 V or less, or may be 0.1 V or less. Note that, when the storage battery 100 is a lithium ion battery, the electrode potential of the negative electrode 140 based on Li / Li+ is, for example, 0.05 V or more and 3.0 V or less.

[0087] In one embodiment, the alkali metal is configured to be able to precipitate and dissolve ions of the alkali metal in the negative electrode 140. For example, if the storage battery 100 is a nonaqueous electrolyte secondary battery, the alkali metal precipitates on the negative electrode 140 when the storage battery 100 is charged. For example, the alkali metal precipitates on the surface of the negative electrode current collector 320. On the other hand, when the storage battery 100 is discharged, the alkali metal in the negative electrode 140 dissolves in the electrolyte 150. In this case, for example, one or more metal materials are used as the negative electrode current collector 320.

[0088] In a modified example, the alkali metal is configured to be able to occlude and release alkali metal ions in the negative electrode 140. For example, if the storage battery 100 is a nonaqueous electrolyte secondary battery, the negative electrode 140 occludes alkali metal ions when the storage battery 100 is being charged. For example, the negative electrode active material layer 340 occludes alkali metal ions (this is sometimes referred to as alkali metal ions being inserted into the negative electrode active material layer 340). On the other hand, when the storage battery 100 is being discharged, the negative electrode 140 releases alkali metal ions into the electrolyte 150. In this case, for example, one or more carbon materials are used as the negative electrode active material layer 340.

[0089] The anode active material layer 340 may be composed of a single layer or multiple layers. When the anode active material layer 340 is composed of multiple layers, the anode active material layer 340 may include a first layer containing anode active material and a second layer containing a conductive material. The second layer may have a lower content of anode active material than the first layer, or may not contain anode active material. In this case, the second layer may be in contact with the anode current collector 320, and the first layer may be electrically connected to the anode current collector 320 via the second layer.

[0090] When the negative electrode active material layer 340 is composed of multiple layers, the negative electrode active material layer 340 may include a resin support layer and a layer containing a negative electrode active material. In this case, the layer containing the negative electrode active material may be formed on one surface of the support layer, or may be formed on both surfaces of the support layer.

[0091] The thickness of the negative electrode active material layer 340 may be 1 to 500 μm, 10 to 200 μm, or 50 to 100 μm. When a foil-shaped or film-shaped alkali metal (sometimes referred to as alkali metal foil) is used as the negative electrode active material layer 340, the thickness of the alkali metal foil may be 10 to 200 μm, or 50 to 100 μm. The thickness and / or mass of the alkali metal foil may be determined depending on the content of the positive electrode active material in the positive electrode active material layer 240.

[0092] In one embodiment, the negative electrode active material layer 340 is produced by processing a material used as the negative electrode active material into a foil or sheet shape. In a modified example, the negative electrode active material layer 340 is formed by depositing a material constituting the negative electrode active material layer 340 on at least one surface of a resin support layer by (i) a slurry coating method, (ii) a physical vapor deposition (PVD) method such as sputtering, vapor deposition, or ion plating, (iii) a chemical vapor deposition (CVD) method, or (iv) an atomic layer deposition (ALD) method.

[0093] In the electrode structure 110, the positive electrode 120 is disposed on the first main surface 132 side of the separator 130. On the other hand, the negative electrode 140 is disposed on the second main surface 134 side of the separator 130. In this case, the first main surface 342 of the negative electrode active material layer 340 may be in contact with the second main surface 134 of the separator 130.

[0094] (Example of Modification) The anode 140 may not have the anode current collector 320. When the anode 140 does not have the anode current collector 320, the anode active material layer 340 may function as the anode current collector 320. Such an anode 140 is used, for example, in a battery having an electrolyte containing alkali metal ions or a battery using alkali metal ions as a carrier. The above battery is fabricated, for example, by incorporating a battery structure including the above anode 140 and an electrolyte containing alkali metal ions into a battery casing. The above battery may be a metal anode battery.

[0095] When the above-described negative electrode 140 is incorporated into, for example, a storage battery 100 that uses alkali metal ions as a carrier, an alkali metal is deposited on the surface of the negative electrode current collector 320 during charging of the storage battery 100. The alkali metal is derived from, for example, alkali metal ions contained in the electrolyte of the storage battery 100. This forms a negative electrode active material layer 340 of the alkali metal. As a result, the negative electrode 140 is produced, which includes a laminate in which the negative electrode current collector 320 and the negative electrode active material layer 340 are laminated in this order.

[0096] 4 schematically shows an example of an electrode structure 410. The electrode structure 410 may be another example of the electrode structure 110. The electrode structure 410 differs from the electrode structure 110 in that it has a wound structure. Except for the above differences, the electrode structure 410 may have the same configuration as the electrode structure 110. The electrode structure 410 may be an example of a battery structure.

[0097] In this example, the electrode structure 410 is produced by winding up a sheet in which the positive electrode 120, the separator 130, the negative electrode 140, and the separator 130 are laminated in this order into a roll. In this example, a positive electrode tab 122 is provided at one end of the positive electrode 120. A negative electrode tab 142 is provided at one end of the negative electrode 140.

[0098] (Example of Modified Example) In this example, an example of the electrode structure 410 has been described, taking as an example a case where the electrode structure 410 includes a single positive electrode tab 122 and a single negative electrode tab 142. However, the electrode structure 410 is not limited to this example. In a modified example, the electrode structure 410 may include multiple negative electrode tabs 142. Also, the electrode structure 410 may include multiple positive electrode tabs 122.

[0099] 5 schematically shows an example of a method for manufacturing the storage battery 100. In this example, an example of a method for manufacturing the storage battery 100 including the negative electrode 140 described in relation to FIG.

[0100] According to this example, first, in step 520 (step may be referred to as S), the negative electrode 140 is prepared. Specifically, for example, a foil- or film-shaped active material containing an alkali metal is prepared. As described above, the active material contained in the negative electrode 140 may be at least one selected from the group consisting of an alkali metal, an alloy containing an alkali metal, and a complex oxide containing an alkali metal. The active material may be an alkali metal or a complex oxide containing an alkali metal.

[0101] According to this example, next, in S530, the positive electrode 120 and the separator 130 are prepared. In S540, the electrode structure 110 is assembled using the positive electrode 120, the separator 130, and the negative electrode 140. Specifically, the negative electrode 140 is disposed on the second main surface 134 side of the separator 130. Furthermore, the positive electrode 120 is disposed on the first main surface 132 side of the separator 130. By repeating the above steps, the electrode structure 110 is assembled. In this way, the electrode structure 110 including the positive electrode 120, the separator 130, and the negative electrode 140 is obtained.

[0102] Next, in S550, the storage battery 100 is assembled using the electrode structure 110. Specifically, the electrode structure 110 and the electrolyte 150 are housed inside the battery case 160. For example, after the electrode structure 110 is placed inside the battery case 160, the inside of the battery case 160 is filled with the electrolyte 150. In this way, the storage battery 100 is obtained.

[0103] Step 520 may be an example of a method for producing an electrode. Steps 520-540 may be an example of a method for producing a battery structure.

[0104] (Example of Modification) In this example, the details of the method for producing an electrode, a battery structure, or a battery have been described using as an example a case in which the negative electrode 140 includes a foil- or film-shaped alkali metal as the negative electrode active material layer 340 and a fiber sheet arranged in contact with the surface of the alkali metal. However, the method for producing an electrode, a battery structure, or a battery is not limited to this example.

[0105] According to a modified example, the negative electrode 140 may include a conductive member and a fiber sheet disposed on the surface of the conductive member. Examples of the conductive member include (i) a foil- or film-like alkali metal, (ii) a conductive substrate and a foil- or film-like alkali metal, and (iii) a conductive substrate (excluding alkali metals). As described above, the negative electrode 140 does not necessarily include the negative electrode active material layer 340. Even in such a case, a carrier metal of the battery is deposited on the surface of the conductive member upon charging the battery, thereby forming a negative electrode active material layer between the conductive member and the fiber sheet. According to the above embodiment, in S520, the above conductive member is prepared instead of a foil- or film-like active material containing an alkali metal.

[0106] (Outline of Electrode Structure 610 and Electrode Structure 710) An outline of electrode structures 610 and 710, which are modified examples of electrode structures 110 and 410, will be described using Figures 6, 7, and 8. In this example, for the purpose of facilitating understanding of electrode structures 610 and 710, details of electrode structures 610 and 710 will be described using an example in which electrode structures 610 and 710 have a stacked structure. Electrode structures 610 and 710 may be an example of a battery structure. Figure 8 schematically shows an example of a unit 812 that constitutes a part of electrode structures 610 and 710.

[0107] 6 schematically shows an example of an electrode structure 610. The electrode structure 610 includes one or more unit units 612 and one or more unit units 614. The electrode structure 610 may be a laminate formed by stacking one or more unit units 612 and one or more unit units 614 in this order.

[0108] The unit 612 has a structural body 620, a negative electrode 140, and a separator 130. The unit 612 may be a laminate formed by stacking the structural body 620, the negative electrode 140, and the separator 130 in this order. The unit 612 may further have a negative electrode tab 142.

[0109] The unit 614 has a structural body 620 and a negative electrode 140. The unit 614 may be a laminate formed by stacking the structural body 620 and the negative electrode 140 in this order. The unit 614 may further have a negative electrode tab 142.

[0110] The structure 620 includes a positive electrode 120, a separator 630, and a support 650. The structure 620 may be a laminate formed by stacking the positive electrode 120, the separator 630, and the support 650 in this order. The structure 620 may further include a positive electrode tab 122.

[0111] The electrode structure 610 differs from the electrode structure 110 and the electrode structure 410 in that a support 650 is provided between at least a separator 630 of one or more separators included in the electrode structure 610 and the negative electrode 140. With respect to the configuration other than the above differences, the electrode structure 610 may have similar features to the electrode structure 110 and / or the electrode structure 410.

[0112] The positive electrode 120 may have a configuration similar to the embodiments described in connection with the electrode structure 110 and / or the electrode structure 410. The separator 130 may have a configuration similar to the embodiments described in connection with the electrode structure 110 and / or the electrode structure 410. The negative electrode 140 may have a configuration similar to the embodiments described in connection with the electrode structure 110 and / or the electrode structure 410.

[0113] (Outline of Separator 630) The separator 630 is disposed between the positive electrode 120 and the negative electrode 140. The separator 630 is disposed between the positive electrode 120 and the support 650, and separates the positive electrode 120 from the support 650.

[0114] The separator 630 is disposed in contact with the positive electrode 120. The separator 630 is disposed so as to cover at least a portion of at least one surface of the positive electrode 120. The separator 630 may be disposed so as to cover substantially the entirety of at least one surface of the positive electrode 120. The separator 630 may be disposed so as to cover the entirety of at least one surface of the positive electrode 120.

[0115] Separator 630 may be made of the same material as separator 130. Separator 630 includes, for example, at least one polymer material selected from the group consisting of cellulose, polyester, polyolefin, polyimide, polyamide, polyvinyl chloride, polytetrafluoroethylene, and polyvinylidene fluoride. Separator 630 may be a porous material made of at least one polymer material selected from the group consisting of cellulose, polyester, polyolefin, polyimide, polyamide, polyvinyl chloride, polytetrafluoroethylene, and polyvinylidene fluoride. The porous material may contain inevitable impurities that are mixed in due to the raw materials or manufacturing process.

[0116] The separator 630 may have the same shape as the separator 130. The separator 630 may have a sheet-like or film-like shape, or may have a sponge-like shape.

[0117] (Outline of Support 650) The support 650 is disposed at a distance from the positive electrode 120. A separator 630 is disposed between the support 650 and the positive electrode 120. The support 650 and the separator 630 may be disposed in contact with each other, or another layer may be disposed between the support 650 and the separator 630. The support 650 may be disposed in contact with the negative electrode 140, or another layer may be disposed between the support 650 and the negative electrode 140.

[0118] The support 650 may contain a salt of an ion used as a carrier in the storage battery 100. The support 650 may contain an inorganic salt composed of an ion used as a carrier in the storage battery 100 and an inorganic anion. The support 650 includes, for example, particles containing the above salt (as described above, these may be referred to as salt particles). In this example, the non-aqueous electrolyte may include an electrolyte commonly used in secondary batteries. The electrolyte acts as a medium for transporting ions involved in the electrochemical reaction in the secondary battery. In particular, a lithium salt can be used as the electrolyte for the electrolyte for a lithium metal secondary battery, and LiPF ６ , LiBF ４ , LiB １２ F １２ , LiAsF６ 、LiFSO ３ 、Li ２ SiF ６ 、LiCF ３ CO ２ 、Lii･ｨ ３ CO ２ 、LiCF ３ SO ３ 、LiC ４ F ９ SO ３ 、LiCF ３ CF ２ SO ３ 、LiCF ３ (CF) ２ ) ７ SO ３ 、LiCF ３ CF ２ (CF) ３ ) ２ Carbon, Li (CF) ３ SO ２ ) ２ H、LinO ３ 、LiN(CN) ２ 、Lii}(FSO) ２ ) ２ 、Lii}(F ２ SO ２ ) ２ 、Lii}(FF ３ SO ２ ) ２ 、LiN(C ２ F ５ SO ２ ) ２ 、Li++(++ ３ SO ２ ) ３ 、Li+P(CF ３ ) ６ 、Li+PF(FF ３ ) ５ 、Li)PF ２ (CF) ３ ) ４ 、Li)PF ３ (CF) ３ ) ３ 、Li)PF ４ (CF) ３ ) ２ 、Li)PF ４ (C ２ F ５ ) ２ 、Li)PF４ (CF ３ SO ２ ) ２ , LiPF ４ (C ２ F ５ SO ２ ) ２ , LiBF ２ C ２ O ４ , LiBC ４ O ８ , LiBF ２ (CF ３ ) ２ , LiBF ２ (C ２ F ５ ) ２ , LiBF ２ (CF ３ SO ２ ) ２ , LiBF ２ (C ２ F ５ SO ２ ) ２ , LiSbF ６ , LiAlO ４ , LiAlF ４ , LiSCN, LiClO ４ , LiCl, LiF, LiBr, LiI, LiAlCl ４ , LiFSI, LiTFSI, etc. The lithium salt may be used alone or in combination of two or more kinds of lithium salts.

[0119] The support 650 may be an object in which the salt particles are supported on any member (sometimes referred to as a substrate). There are no particular limitations on the manner in which the salt particles are supported on the support 650. In the support 650, the salt particles may be supported or held by the substrate, or the salt particles may adhere to the substrate.

[0120] (Other Examples of the Structure of the Support 650) The support 650 may be produced by molding salt particles. For example, the support 650 is produced by pressure molding salt particles. The support 650 may also be produced by pressure molding a mixture of salt particles and a binder material. A resin known as a binder is used as the binder material.

[0121] In this case, the volume of the ion salt carried by the support 650 is, for example, 0.1 vol% or more and 40 vol% or less with respect to the volume of the separator 630. The above ratio may be 0.5 vol% or more and preferably 30 vol% or less. The above ratio may be 1 vol% or more and more preferably 20 vol% or less.

[0122] (Overview of Salt Particles) The salt particles may be salt crystals. The salt particles may be particles that are substantially composed of an ionic salt. For example, when the ratio of the mass of the ionic salt to the mass of the salt particles is 50 mass% or more, the salt particles can be determined to be substantially composed of an ionic salt.

[0123] The carrier of the storage battery 100 is, for example, an alkali metal or an alkaline earth metal. When the carrier of the storage battery 100 is an alkali metal, the salt particles include a solid alkali metal salt. The alkali metal salt may be an inorganic alkali metal salt. When the carrier of the storage battery 100 is an alkaline earth metal, the salt particles include a solid alkaline earth metal salt. The alkali metal salt may be an inorganic alkaline earth metal salt.

[0124] The alkali metal salt includes at least one alkali metal salt selected from the group consisting of fluoride salts, chloride salts, bromide salts, iodide salts, nitrate salts, nitrite salts, borate salts, fluoroborate salts, phosphate salts, fluorophosphate salts, sulfate salts, and fluorosulfate salts. The fluoroborate salt may be a tetrafluoroborate salt. The fluorophosphate salt may be a difluorophosphate salt.

[0125] The alkaline earth metal salt includes at least one alkali metal salt selected from the group consisting of fluoride salts, chloride salts, bromide salts, iodide salts, nitrate salts, nitrite salts, borate salts, fluoroborate salts, phosphate salts, fluorophosphate salts, sulfate salts, and fluorosulfate salts. The fluoroborate salt may be a tetrafluoroborate salt. The fluorophosphate salt may be a difluorophosphate salt.

[0126] (Example of Manufacturing Method of Unit 612) The unit 612 can be manufactured, for example, by the following procedure. First, the positive electrode 120, the separator 630, and the support 650 are prepared. Next, the separator 630 is disposed between the positive electrode 120 and the support 650, to manufacture a structure in which the positive electrode 120, the separator 630, and the support 650 are arranged in this order. In this case, the separator 630 is disposed between the positive electrode 120 and the support 650 so that the positive electrode 120 and the separator 630 are in contact with each other.

[0127] (Example of Modified Example) In this example, the details of the electrode structure 610 have been described using as an example a case where the electrode structure 610 includes one or more unit units 612 and one or more unit units 614. However, the electrode structure 610 is not limited to this example. In a modified example, the electrode structure 610 may include a plurality of unit units 614 and one or more separators 130. The electrode structure 610 includes, for example, N (N is an integer of 2 or more) unit units 614 and N-1 separators 130.

[0128] In this example, the details of the electrode structure 610 have been described using an example in which the electrode structure 610 has a stacked structure. However, the electrode structure 610 is not limited to this example. In a modified example, the electrode structure 610 may have a wound structure. Furthermore, a person skilled in the art who has read the description of this specification will understand that the technical matters related to the electrode structure 610 can be applied to an electrode structure having a wound structure.

[0129] 7 schematically shows an example of an electrode structure 710. The electrode structure 710 includes one or more unit units 712 and one or more unit units 714. The electrode structure 710 may be a laminate formed by stacking one or more unit units 712 and one or more unit units 714 in this order.

[0130] The unit 712 has a structure 720, a negative electrode 140, a support 750, and a separator 130. The unit 714 has a structure 720 and a negative electrode 140. The structure 720 may have the same configuration as the structure 620 described in relation to FIG. 6 .

[0131] The unit 712 differs from the unit 612 of the electrode structure 610 described in FIG. 6 in that it includes a support 750. The unit 712 of this example may be a laminate formed by stacking a structure 720, a negative electrode 140, a support 750, and a separator 130 in this order. The support 750 may be disposed on both one surface of the negative electrode 140 and the other surface opposite the one surface. That is, the support 750 may be disposed on both sides of the negative electrode 140. In this case, the unit 712 may be a laminate formed by stacking a positive electrode 120, a separator 730, a support 750, a negative electrode 140, a support 750, and a separator 130 in this order.

[0132] An example of a modified example of the unitary unit 612 and the unitary unit 712 will be described using Fig. 8. The unitary unit 812 described in relation to Fig. 8 differs from the unitary unit 612 and the unitary unit 712 in that a part of the negative electrode 840 functions as a support 850. Regarding the configuration other than the above-mentioned difference, the unitary unit 812 may have similar features to the unitary unit 612 and the unitary unit 712.

[0133] 8, the positive electrode 120 includes a positive electrode current collector 220 and a positive electrode active material layer 240 disposed on at least one surface of the positive electrode current collector 220. The positive electrode current collector 220 may be a member similar to the positive electrode current collector 220 described in relation to FIG. 2, or may be a fiber sheet including resin filaments plated with a metal.

[0134] The negative electrode 840 may include a negative electrode current collector 320, a negative electrode active material layer 340 disposed on at least one surface of the negative electrode current collector 320, and a fiber layer 860. The negative electrode current collector 320 and the negative electrode active material layer 340 may be the same members as the negative electrode current collector 320 and the negative electrode active material layer 340 described in FIG.

[0135] (Fiber Layer) The fiber layer 860 is disposed on one surface of the negative electrode active material layer 340. The fiber layer 860 may be disposed in contact with the negative electrode active material layer 340. The fiber layer 860 may be disposed so as to cover the negative electrode active material layer 340.

[0136] In this example, the fiber layer 860 has a plurality of fibers or fiber bundles (sometimes referred to as filaments). The plurality of filaments form one or more voids extending from the surface of the fiber layer 860 to the interior of the fiber sheet. Examples of the fiber layer 860 include sheet-like nonwoven fabrics and woven fabrics.

[0137] The negative electrode 840 in this example includes a negative electrode active material layer 340 and a fiber layer 860 arranged on one surface of the negative electrode current collector 320, and a negative electrode active material layer 340 and a fiber layer 860 arranged on the other surface of the negative electrode current collector 320. The negative electrode current collector 320 is arranged on one surface of the negative electrode active material layer 340, and the fiber layer 860 is arranged on the other surface of the negative electrode active material layer 340.

[0138] The fiber layer 860 functions as the support 850. In this example, the fiber layer 860 disposed on one side of the negative electrode current collector 320 functions as the support 850, but is not limited to this. The fiber layer 860 disposed between the negative electrode current collector 320 and the separator 130 may function as the support 850, or both of the fiber layers 860 disposed on both sides of the negative electrode current collector 320 may function as the support 850.

[0139] The fiber layer 860 includes salt particles 852, which are an example of the salt particles described above. The fiber layer 860 is used as a base material of the carrier 850. The fiber layer 860 is a porous material composed of a plurality of filaments. In one embodiment, the fiber layer 860 can support or hold the salt particles 852 on its surface and / or inside the pores. In a variant, the salt particles 852 can be attached to the filaments that make up the fiber layer 860.

[0140] The support 850 includes a fiber layer 860 disposed on the surface of the first negative electrode active material layer 340 opposite to the surface in contact with the negative electrode current collector 320, and one or more salt particles 852 supported or held by the fiber layer 860 or attached to the fiber layer 860. As a result, the fiber layer 860 disposed on one side of the negative electrode current collector 320 functions as the support 850 described above. However, the fiber layers 860 disposed on both sides of the negative electrode current collector 320 may also function as the support 850 described above.

[0141] The unit 812 may be an example of a structure. The salt particles 852 may be an example of a solid alkali metal salt.

[0142] (Example of Modification) In a modification, instead of or in addition to the fiber layer 860, the negative electrode current collector 320 included in the negative electrode 840 may function as the above-described support 850. Specifically, the negative electrode current collector 320 includes salt particles 852. In this case, the negative electrode current collector 320 includes, for example, (i) the salt particles 852 and (ii) a substrate for supporting or holding the salt particles 852 and / or a substrate for attaching the salt particles 852. The substrate may be a porous material. The substrate may be a fiber sheet. The negative electrode current collector 320 may be produced by molding the salt particles 852, as described above.

[0143] In a further modified example, instead of or in addition to the fiber layer 860, at least one of the two negative electrode active material layers 340 included in the negative electrode 840 may function as the support 850 described above. Specifically, at least one of the two negative electrode active material layers 340 includes salt particles 852. Alternatively, both of the two negative electrode active material layers 340 included in the negative electrode 840 may function as the support 850 described above. Specifically, both of the two negative electrode active material layers 340 include salt particles 852. The negative electrode active material layer 340 includes, for example, (i) salt particles 852 and (ii) a substrate for supporting or holding the salt particles 852 and / or a substrate for attaching the salt particles 852. The substrate may be a porous material. The substrate may be a fiber sheet. The negative electrode active material layer 340 may be produced by molding the salt particles 852, as described above.

[0144] In a further modification, instead of or in addition to the fiber layer 860, salt particles 852 may be coated on at least one surface of the negative electrode 840, thereby functioning as the above-described support 850. Specifically, the salt particles 852 are coated on the surface of the negative electrode 840 by applying a slurry in which the salt particles 852 are suspended to at least one surface of the negative electrode 840. The salt particles 852 may also be coated on both surfaces of the negative electrode 840.

[0145] In a further modified example, instead of or in addition to the fiber layer 860, salt particles 852 may be coated on the surface of the separator 630 facing the negative electrode 840, thereby functioning as the above-described support 850. Specifically, a slurry in which the salt particles 852 are suspended is applied to the surface of the separator 630 facing the negative electrode 840, thereby coating the salt particles 852 on the surface of the separator 630. In this case, the negative electrode 840 may have a structure that does not include the fiber layer 860, as described in FIG. 3 .

[0146] To more specifically describe the storage battery 100, the details of the storage battery 100 will be described in the following examples. However, various modifications and improvements may be made to the following examples, and the storage battery 100 is not limited to the following examples.

[0147] Example 1 A test pouch cell was produced. Specifically, a test pouch cell was produced according to the following procedure.

[0148] (1) Preparation of Negative Electrode A negative electrode having the same configuration as the negative electrode 140 described in relation to FIG. 3 was prepared by the following procedure. First, a Li metal foil having a thickness of 100 μm and a purity of 99.5% or more was prepared. The planar shape of the Li metal foil was a square with a length of 40 mm and a width of 40 mm. The Li metal foil was placed on a negative electrode current collector. Next, a terminal was welded to the metal foil. This produced a negative electrode.

[0149] (2) Preparation of Positive Electrode A positive electrode was prepared by the following procedure. First, a number-based median diameter (D ５０ ) is 5 μm NCM (LiNi １／３ Mn １／３ Co １／３ O ２ Carbon black and graphite were prepared as conductive additives. PVdF (polyvinylidene fluoride) was prepared as a binder.

[0150] Next, PVdF and N-methyl-2-pyrrolidinone (NMP) were mixed to prepare 50 g of a PVdF NMP solution. The PVdF content in the NMP solution was 10 wt %. Next, 85 g of NCM, 5 g of carbon black, and 5 g of graphite were mixed. Then, the above mixture was mixed with 50 g of the above PVdF NMP solution to prepare 145 g of paint.

[0151] Next, the above coating material was applied to the surface of an aluminum foil having a thickness of 20 μm by a doctor blade method. The coating material was dried at a temperature of 90 ° C. to obtain an aluminum foil having a positive electrode active material layer formed thereon. The aluminum foil was then pressed into a square having a length of 40 mm and a width of 40 mm, and a terminal was then welded thereto. This produced a positive electrode.

[0152] (3) Preparation of Separator A polyethylene film (#2320, manufactured by Celgard, USA) was prepared as a separator. The planar shape of the separator was a square with a length of 45 mm and a width of 45 mm. The thickness of the separator was 20 μm. The porosity of the separator was 39%.

[0153] (4) Preparation of Electrolyte Solution The electrolyte solution used in Example 1 of the present invention was prepared by the following procedure. The raw materials listed in Example 1 of Table 1 were mixed and stirred to a predetermined mass % to prepare an electrolyte solution. In this case, the electrolyte was dissolved in a non-aqueous solvent while cooling so that the liquid temperature did not exceed 40°C, and then the other raw materials were added, mixed, and stirred. Specifically, lithium hexafluorophosphate (LiPF ) was dissolved in a mixed solvent (EC, manufactured by Kishida Chemical Co., Ltd., purity 99.5%) of ethylene carbonate (EC:DMC=23:60 mass %) and dimethyl carbonate (DMC, manufactured by Kishida Chemical Co., Ltd., purity 99.5%). ６ 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE, manufactured by Tokyo Chemical Industry Co., Ltd., purity 95%) as hydrofluoroether (HFE) and lithium nitrate (LiNO ３ , manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., purity 98%) was added and mixed with stirring.

[0154] Lithium nitrate does not have to be completely dissolved in the electrolyte solution. Lithium nitrate may be suspended in the electrolyte solution. Lithium nitrate may be mixed into the electrolyte solution at a predetermined volume percentage relative to the volume of the separator prepared previously.

[0155] (5) Preparation of Laminate: The separator was placed on the lithium foil surface of the negative electrode. Next, the positive electrode was placed on the separator so that the surface of the positive electrode active material of the positive electrode was in contact with the surface of the separator. This resulted in a laminate in which the negative electrode, separator, and positive electrode were stacked in this order.

[0156] The laminate may have a support containing lithium nitrate prepared by a known method. For example, the laminate may be prepared by immersing a cellulose nonwoven fabric in an ethanol solution of lithium nitrate, removing it after a predetermined time, drying it under reduced pressure at 80°C for 1 hour using a dryer, and cutting it into a piece 43 mm wide and 43 mm long. The laminate may have a support prepared by pressure molding salt particles. The support may contain an alkali metal salt, alkaline earth metal salt, or nitrate salt other than lithium nitrate. The laminate may be provided between the surface of the negative electrode on which the lithium foil is disposed and the surface of the separator. That is, the laminate may have a negative electrode, a support, a separator, and a positive electrode stacked in this order.

[0157] (6) Preparation of a test pouch cell First, the above-mentioned laminate was placed inside a bag-shaped aluminum laminate having an opening. Next, the electrolyte solution of Example 1 in Table 1 was vacuum-injected into the aluminum laminate. Next, the opening of the aluminum laminate was heated and sealed. This gave a test pouch cell.

[0158] (Examples 2 to 20) Test pouch cells shown in Examples 2 to 20 in Table 1 were prepared according to the same procedure as in Example 1, except that the type of electrolyte was changed. In the preparation examples of Examples 2 to 20, the amount of lithium nitrate and the composition of the non-aqueous solvent were changed. In Examples 3, 5, 7, 9, 11, 13, 15, 17, and 19, the lithium nitrate content was increased. In Examples 2, 4, 6, 8, 10, 12, 14, 16, 18, and 20, fluoroethylene carbonate (FEC, manufactured by Kishida Chemical Co., Ltd., purity 99.5%) was used instead of EC. [Table 1]

[0159] (Examples 21 to 26) Test pouch cells shown in Examples 21 to 26 in Table 2 were produced according to the same procedure as in Example 10, except that the type of electrolyte was changed. In the production examples of Examples 21 to 26, the content of TTE used as the HFE was changed. [Table 2]

[0160] Examples 27 to 29 Test pouch cells described in Examples 27 to 29 in Table 3 were produced according to the same procedure as in Example 10, except that the type of electrolyte was changed. In the production examples of Examples 27 to 29, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether (OTE, manufactured by Tokyo Chemical Industry Co., Ltd., purity 95%), 3,3,4,4-tetrafluorotetrahydrofuran (FTHF, manufactured by Tokyo Chemical Industry Co., Ltd., purity 95%), and 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)pentane (HFE-7300, manufactured by Tokyo Chemical Industry Co., Ltd., purity 95%) were used instead of TTE as the HFE. [Table 3]

[0161] (Example 30) A test pouch cell described in Example 30 in Table 4 was produced according to the same procedure as in Example 10, except that the type of electrolyte was changed. In the production example of Example 30, ethyl methyl carbonate (EMC, manufactured by Kishida Chemical Co., Ltd., purity 99.5%) was used as the non-aqueous solvent instead of DMC. [Table 4]

[0162] (Examples 31 and 32) Test pouch cells shown in Examples 31 and 32 in Table 5 were prepared according to the same procedure as in Example 10, except that the type of electrolyte was changed. In the preparation examples of Examples 31 and 32, LiPF 5 was used as the electrolyte. ６ The amount of was varied. [Table 5]

[0163] (Examples 33 and 34) Test pouch cells shown in Examples 33 and 34 in Table 6 were prepared according to the same procedure as in Example 10, except that the type of electrolyte was changed. In the preparation examples of Examples 33 and 34, LiPF 6 was used as the electrolyte. ６ Instead of the above, lithium bis(fluorosulfonyl)imide (LiFSI, manufactured by Kishida Chemical Co., Ltd., purity 99.9%) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI, manufactured by Kishida Chemical Co., Ltd., purity 99.9%) were used. [Table 6]

[0164] (Examples 35 to 40) Test pouch cells shown in Examples 35 to 40 in Table 7 were prepared according to the same procedure as in Example 10, except that the type of electrolyte was changed. In the preparation examples of Examples 35 to 40, the content of FEC introduced into the electrolyte was increased. When the FEC content was below 23% by mass, the mixing ratio of EC and DMC constituting the non-aqueous solvent was changed. [Table 7]

[0165] (Comparative Examples 1 to 22) Test pouch cells shown in Comparative Examples 1 to 22 in Table 8 were prepared according to the same procedure as in Example 1, except that the type of electrolyte was changed. In the preparation examples of Comparative Examples 1 to 22, no HFE was added. In Comparative Examples 1 and 2, no lithium nitrate was added. In Comparative Examples 3, 5, 7, 9, 11, 13, 15, 17, 19, and 21, the content of lithium nitrate was increased. In Comparative Examples 4, 6, 8, 10, 12, 14, 16, 18, 20, and 22, fluoroethylene carbonate (FEC, manufactured by Kishida Chemical Co., Ltd., purity 99.5%) was used instead of EC. [Table 8]

[0166] (Comparative Examples 23 to 30) Test pouch cells shown in Comparative Examples 23 to 30 in Table 9 were produced according to the same procedure as Comparative Example 1, except that the type of electrolyte was changed. In the production examples of Comparative Examples 23 to 30, lithium nitrate was not added, and the type of HFE was changed. [Table 9]

[0167] (Comparative Example 31) A test pouch cell described in Comparative Example 31 in Table 10 was produced according to the same procedure as in Comparative Example 12, except that the type of electrolyte was changed. In the production example of Comparative Example 31, ethyl methyl carbonate (EMC, manufactured by Kishida Chemical Co., Ltd., purity 99.5%) was used as the non-aqueous solvent instead of DMC. [Table 10]

[0168] (Comparative Examples 32 and 33) Test pouch cells shown in Comparative Examples 32 and 33 in Table 11 were produced according to the same procedure as in Comparative Example 12, except that the type of electrolyte was changed. In the production examples of Comparative Examples 32 and 33, LiPF 5 was used as the electrolyte. ６ The amount of was varied. [Table 11]

[0169] (Comparative Examples 34 and 35) Test pouch cells shown in Comparative Examples 34 and 35 in Table 12 were produced according to the same procedure as in Comparative Example 12, except that the type of electrolyte was changed. In the production examples of Comparative Examples 34 and 35, LiPF 6 was used as the electrolyte. ６ LiFSI and LiTFSI were used instead of Table 12.

[0170] (Comparative Examples 36 to 41) Test pouch cells shown in Comparative Examples 36 to 41 in Table 13 were produced according to the same procedure as in Comparative Example 12, except that the type of electrolyte solution was changed. In the production examples of Comparative Examples 36 to 41, the content of FEC introduced into the electrolyte solution was increased. When the FEC content was below 23 mass%, the mixing ratio of EC and DMC constituting the non-aqueous solvent was changed. [Table 13]

[0171] (Evaluation) A cycle test was conducted on each of the test batteries prepared in each Example and Comparative Example. Specifically, the test batteries were charged and discharged at 0.1 C in a 25°C environment to measure the initial charge / discharge capacity, and then 200 cycles were repeated under the following cycle conditions: charging to 4.2 V at 0.2 C and discharging to 3 V at 0.1 C. The ratio of the discharge capacity after 100 cycles and after 200 cycles to the initial charge / discharge capacity was defined as the discharge capacity retention rate (%). The evaluation results of the cycle test for each Example and Comparative Example are shown in Tables 1 to 13.

[0172] (1) Evaluation with and without Hydrofluoroether The effect of adding hydrofluoroether will be described with reference to Tables 1 and 8. Comparing Example 1 with Comparative Example 3, it can be seen that the addition of hydrofluoroether significantly improves the cycle characteristics of the storage battery, even under conditions where the amount of lithium nitrate introduced is as low as 1 mass % or less.

[0173] Next, with reference to Comparative Examples 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, and 21, which do not contain hydrofluoroether, the cycle characteristics of the storage battery improve as the amount of lithium nitrate introduced increases, but plateau when the amount of lithium nitrate introduced reaches approximately 18 mass%, and further increase in the amount of lithium nitrate introduced deteriorates the cycle characteristics. On the other hand, with reference to Examples 1, 3, 5, 7, 9, 11, 13, 15, 17, and 19, which contain hydrofluoroether, the cycle characteristics of the storage battery improve as the amount of lithium nitrate introduced increases, even when the amount of lithium nitrate introduced exceeds 18 mass%. Thus, by including both hydrofluoroether and hydrofluoroether in the electrolyte, the cycle characteristics of the storage battery do not deteriorate even when the lithium nitrate content is increased.

[0174] (2) Evaluation with and without fluoroethylene carbonate The effect of adding fluoroethylene carbonate will be described with reference to Tables 1 and 8. With reference to Comparative Examples 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, and 22, the addition of fluoroethylene carbonate to an electrolyte solution containing lithium nitrate improved the cycle characteristics of the storage battery. On the other hand, with reference to Examples 1, 3, 5, 7, 9, 11, 13, 15, 17, and 19, the cycle characteristics of the storage battery were improved compared to those of the above-mentioned Comparative Examples. That is, the addition of hydrofluoroether to an electrolyte solution containing lithium nitrate provided a greater effect of improving the cycle characteristics than the addition of fluoroethylene carbonate to an electrolyte solution containing lithium nitrate. Furthermore, with reference to Examples 2, 4, 6, 8, 10, 12, 14, 16, 18, and 20, it can be seen that the addition of fluoroethylene carbonate to a storage battery containing lithium nitrate and hydrofluoroether further improved the cycle characteristics of the storage battery.

[0175] (3) Evaluation by Hydrofluoroether Content The effects of different amounts of hydrofluoroether added will be described with reference to Tables 2 and 8. A comparison of Example 21 with Comparative Example 12 shows that the cycle characteristics of the storage battery are improved by adding 1 mass % of hydrofluoroether. Furthermore, reference to the Examples listed in Table 2 shows that the cycle characteristics of the storage battery are improved by adding 1 mass % or more of hydrofluoroether to the electrolyte.

[0176] (4) Evaluation by Type of Hydrofluoroether The effects of different types of hydrofluoroether will be described with reference to Tables 3 and 9. Referring to Examples 10 and 27 to 29 in Table 3, high cycle characteristics were observed when TTE, OTE, FTHF, and HFE-7300 were all used. In particular, the cycle characteristics when TTE was used were higher than when other hydrofluoroethers were used. A comparison of Examples 10, 27 to 29 and Comparative Examples 24, 26, 28, and 30 reveals that the cycle characteristics of the storage battery are improved when any type of hydrofluoroether is combined with lithium nitrate.

[0177] (5) Effect of Hydrofluoroether When the Non-aqueous Solvent is Changed The effect of the presence or absence of hydrofluoroether when the non-aqueous solvent is changed will be described with reference to Tables 4 and 10. A comparison of Example 30 and Comparative Example 31 shows that by providing the test pouch cell with the hydrofluoroether of Example 30, superior cycle characteristics were achieved compared to Comparative Example 31, even when EMC was used instead of DMC as the non-aqueous solvent.

[0178] (6) Effect of Hydrofluoroether When the Electrolyte Content is Changed The effect of the presence or absence of hydrofluoroether when the electrolyte content is changed will be described with reference to Tables 5 and 11. A comparison of Examples 31 and 32 with Comparative Examples 32 and 33 shows that by providing the test pouch cells with the hydrofluoroethers of Examples 31 and 32, they have superior cycle characteristics compared to Comparative Examples 32 and 33, even when the amount of electrolyte introduced is increased or decreased.

[0179] (7) Effect of Hydrofluoroether When the Type of Electrolyte is Changed The effect of the presence or absence of hydrofluoroether when the type of electrolyte is changed will be explained with reference to Tables 6 and 12. Comparing Examples 33 and 34 with Comparative Examples 34 and 35, it was found that by providing the hydrofluoroether of Examples 33 and 34 in the test pouch cells, the effect of using LiPF as the electrolyte was improved. ６It can be seen that even when LiFSI or LiTFSI was used instead of LiF, the battery had excellent cycle characteristics compared to Comparative Examples 34 and 35.

[0180] (8) Effect of Hydrofluoroether When the Fluoroethylene Carbonate Content is Varying The effect of the presence or absence of hydrofluoroether when the fluoroethylene carbonate content is varied will be described with reference to Tables 7 and 13. A comparison of Examples 35 to 40 with Comparative Examples 36 to 41 shows that by providing the test pouch cells with the hydrofluoroethers of Examples 35 to 40, superior cycle characteristics are achieved compared to Comparative Examples 36 to 41, even when the fluoroethylene carbonate content is increased or decreased.

[0181] (9) A comparison of Examples 1 to 40 and Comparative Examples 1 to 41 listed in Summary Tables 1 to 13 reveals that the test pouch cell according to the present embodiment, which contains both lithium nitrate and hydrofluoroether, has superior cycle characteristics compared to the test pouch cells of Comparative Examples 1 to 41, which do not contain either lithium nitrate or hydrofluoroether. It is also revealed that the cycle characteristics are further improved when the test pouch cell contains fluoroethylene carbonate in addition to lithium nitrate and hydrofluoroether.

[0182] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0183] It should be noted that the order of execution of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before," "prior to," etc., and that the processes can be performed in any order unless the output of a previous process is used in a subsequent process. Even if the operational flow in the claims, specifications, and drawings is described using "first," "next," etc. for convenience, this does not mean that the processes must be performed in this order.

[0184] 100...storage battery, 110...electrode structure, 120...positive electrode, 122...positive electrode tab, 130...separator, 132...first main surface, 134...second main surface, 140...negative electrode, 142...negative electrode tab, 150...electrolyte, 160...battery case, 162...positive electrode terminal, 164...negative electrode terminal, 172...positive electrode lead, 174...negative electrode lead, 220...positive electrode current collector, 222...first main surface, 224...second main surface, 226...side surface, 240...positive electrode active material layer, 320...negative electrode current collector, 322...first main surface, 324...second main surface, 3 26...side surface, 340...negative electrode active material layer, 342...first main surface, 344...second main surface, 346...side surface, 410...electrode structure, 610...electrode structure, 612...unit, 614...unit, 620...structure, 630...separator, 650...support, 710...electrode structure, 712...unit, 714...unit, 720...structure, 730...separator, 750...support, 812...unit, 840...negative electrode, 850...support, 852...salt particles, 860...fiber layer

Claims

1. A battery comprising: a positive electrode; a negative electrode disposed spaced apart from the positive electrode; a separator sandwiched between the positive electrode and the negative electrode; and an electrolyte, wherein the electrolyte contains at least lithium nitrate and contains 0.1% to 50% of an alkali metal salt, alkaline earth metal salt, or nitrate, relative to the total mass of the electrolyte, and 1% to 40% of a hydrofluoroether, relative to the total mass of the electrolyte.

2. The battery according to claim 1, wherein the electrolyte contains 10% or more and 70% or less of fluoroethylene carbonate based on the total mass of the electrolyte.

3. The battery according to claim 1, wherein the electrolytic solution contains: 7% or more and 30% or less of an electrolyte based on the total mass of the electrolytic solution; and 10% or more and 90% or less of a non-aqueous solvent based on the total mass of the electrolytic solution.

4. The battery of claim 1, wherein the alkali metal salt, alkaline earth metal salt, or nitrate salt comprises at least one selected from potassium nitrate, sodium nitrate, magnesium nitrate, cesium nitrate, calcium nitrate, zinc nitrate, silver nitrate, lead nitrate, or copper nitrate.

5. The hydrofluoroethers include 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, 1H,1H,5H-octafluoropentyl 1,1,2,2-tetrafluoroethyl ether, 3,3,4,4-tetrafluorotetrahydrofuran, 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)pentane, hexafluoroisopropyl methyl ether, methyl nonafluorobutyl ether, and methyl 2,2,3,3 1,3-pentafluoropropyl ether, 1,1,2,3,3,3-hexafluoropropyl methyl ether, 1,1,2,3,3,3-hexafluoropropyl ethyl ether, 1,1,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether, bis(2,2,2-trifluoroethyl) ether, methyl 1,1,2,2-tetrafluoroethyl ether, or ethyl 1,1,2,2-tetrafluoroethyl ether.

6. The electrolyte is lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, LiBF ４ , LiClO ４ , LiC(CF ３ SO ２ ) ３ , LiCH(CF ３ SO ２ ) ２ , LiF, LiCl, LiBr, LiI, Li ２ S, LiB １２ F １２ , LiAsF ６ , LiFSO ３ , Li ２ SiF ６ , LiCF ３ CO ２ , LiCH ３ CO ２ , LiCF ３ SO ３ , LiC ４ F ９ SO ３ , LiCF ３ CF ２ SO ３ , LiCF ３ (CF ２ ) ７ SO ３ , LiCF ３ CF ２ (CF ３ ) ２ CO, Li(CF ３ SO ２ ) ２ CH, LiNO ３ , LiN (CN) ２ , LiN(FSO ２ ) ２ , LiN(F ２ SO ２ ) ２ , LiN(CF ３ SO ２ ) ２ , LiN(C ２ F ５ SO ２ ) ２ , LiP(CF ３ ) ６ , LiPF(CF ３ ) ５ , LiPF ２ (CF ３ ) ４ , LiPF ３ (CF ３ ) ３ , LiPF ４ (CF ３ ) ２ , LiPF ４ (C ２ F ５ ) ２ , LiPF ４ (CF ３ SO ２ ) ２ , LiPF ４ (C ２ F ５ SO ２ ) ２ , LiBF ２ C ２ O ４ , LiBC ４ O ８ , LiBF ２ (CF ３ ) ２ , LiBF ２ (C ２ F ５ ) ２ , LiBF ２ (CF ３ SO ２ ) ２ , LiBF ２ (C ２ F ５ SO ２ ) ２ , LiSbF ６ , LiAlO ４ , LiAlF ４ , LiSCN or LiAlCl ４ The battery according to claim 3 , comprising at least one selected from the group consisting of:

7. The battery according to claim 3, wherein the non-aqueous solvent contains at least one selected from saturated acyclic diethers (excluding 1,2-dimethoxyethane) or cyclic ethers having 6 or fewer carbon atoms, cyclic carbonates or saturated acyclic carbonates having 5 or fewer carbon atoms, difluoroethylene carbonate, and cyclic esters or saturated acyclic esters having 5 or fewer carbon atoms.

8. The battery of claim 3, wherein the non-aqueous solvent includes at least one selected from the group consisting of 1,2-dimethoxyethane, 1,3,5-trioxane, diethylene glycol dimethyl ether, dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, difluoroethylene carbonate, γ-butyrolactone, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, and ethyl propionate.

9. The battery of claim 1, wherein the electrolyte solution contains at least one additive in an amount of 0.01% or more and 15% or less, based on the total mass of the electrolyte solution.

10. The battery of claim 9, wherein the additive comprises at least one selected from tetravinylsilane, vinylene carbonate, chloroethylene carbonate, lithium difluoroacetate, fluorobenzene, ortho-fluorotoluene, meta-fluorotoluene, para-fluorotoluene, ethylbenzene, adiponitrile, succinonitrile, 1,3,6-hexanetricyanide, 1,3-propane sultone, ethylene sulfite, lithium difluorooxalatoborate, and lithium bisoxalatoborate.

11. The battery according to any one of claims 1 to 10, wherein the total mass of the hydrofluoroether is 5% or more and 20% or less of the total mass of the electrolyte.

12. The battery according to any one of claims 1 to 10, wherein the hydrofluoroether comprises 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether in an amount of 5% or more and 20% or less based on the total mass of the electrolyte.

13. The battery of claim 12, wherein the electrolyte contains 20% or more and 55% or less of fluoroethylene carbonate based on the total mass of the electrolyte.

14. A battery comprising: a positive electrode; a negative electrode disposed spaced apart from the positive electrode; a separator sandwiched between the positive electrode and the negative electrode; an electrolyte; and an alkali metal salt, alkaline earth metal salt, or nitrate containing at least lithium nitrate in an amount of 0.1% to 40% by volume of the separator, the amount being equal to or greater than 1% and equal to or less than 40% by volume of the separator, the electrolyte containing 1% to 40% by volume of a hydrofluoroether in relation to the total mass of the electrolyte.

15. The battery according to claim 14, wherein the alkali metal salt, alkaline earth metal salt, or nitrate is 1% or more and 30% or less by volume of the separator, the hydrofluoroether comprises 5% or more and 20% or less of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether by total mass of the electrolyte, and the electrolyte comprises 20% or more and 55% or less of fluoroethylene carbonate by total mass of the electrolyte.

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