Electrode composition, electrode for secondary battery, secondary battery, electrolyte permeation method, and method for manufacturing secondary battery

Abstract

An electrode composition for a secondary battery electrode layer containing an electrolyte solution, the electrode composition satisfying all of the following conditions (1)-(4): (1) the electrode composition contains an active material and an additive and does not contain a binder resin; (2) the HSP distance (RaAct) between the additive and the active material is 12.0 MPa 0.5 or less; (3) the HSP distance (RaElec) between the additive and the electrolyte solution is 14.0 MPa 0.5 or less; and (4) the weight-average molecular weight (Mw) of the additive is 50,000 or less.

Description

Technical Field

[0001] The present invention relates to an electrode composition, an electrode for a secondary battery, a secondary battery, an electrolyte infiltration method and a method for manufacturing a secondary battery. Background Art

[0002] Secondary batteries such as lithium-ion batteries have been put into practical use as batteries for portable terminals represented by mobile phones and laptop computers, as well as batteries as power sources in hybrid vehicles and electric vehicles. In order to further popularize them, high capacity and high output of secondary batteries are required, and attempts to apply various technologies have been made.

[0003] As one of the methods to increase the capacity of secondary batteries, there is a method of increasing electrode density. By densely filling the active material, more capacity can be obtained. However, if the electrode density is increased, it is difficult for the electrolyte to penetrate into the electrode, and there is a problem that only a capacity less than the theoretical value can be extracted, and the output characteristics deteriorate.

[0004] In order to solve such a problem, Patent Document 1 discloses a technology that can improve the permeability of the electrolyte by providing grooves on the electrode surface. Patent Document 2 discloses a technology that improves the permeability of the electrolyte by studying the particle size and shape of the active material. In addition, Patent Document 3 discloses a technology that improves the permeability of the electrolyte by adjusting the electrode density.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2008-27633

[0008] Patent Document 2: Japanese Patent Application Publication No. 2012-151088

[0009] Patent Document 3: Japanese Patent Application Publication No. 2020-053282 Summary of the invention

[0010] Problems to be solved by the invention

[0011] However, the method of Patent Document 1 has a problem in that it includes a step of pressing with a roller having projections and depressions in order to form grooves on the surface of the electrode, and thus requires the introduction of new equipment.

[0012] In addition, in the methods of Patent Documents 2 and 3, although some improvement in permeability is observed, the effect is not sufficient.

[0013] The present invention is an invention for solving the above-mentioned problems, and an object of the present invention is to provide an electrode composition capable of producing an electrode having excellent electrolyte permeability.

[0014] Means for solving problems

[0015] The present inventors have conducted intensive studies and, as a result, have completed the present invention.

[0016] The present invention relates to any of the following schemes.

[0017] An electrode composition, which is an electrode composition for a secondary battery electrode layer containing an electrolyte, wherein the electrode composition satisfies all of the following conditions (1) to (4): (1) containing an active material and an additive, and not containing a binder resin; (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa 0.5 Below; (3) the HSP distance (Ra_Elec) between the above-mentioned additive and the above-mentioned electrolyte is 14.0MPa 0.5 (4) the weight average molecular weight (Mw) of the above-mentioned additive is 50,000 or less.

[0018] An electrode composition, which is an electrode composition for a secondary battery electrode layer containing an electrolyte, wherein the electrode composition satisfies all of the following conditions (1) to (3): (1) containing an active material, a binder resin and an additive; (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa 0.5 Below; (3) the HSP distance (Ra_Elec) between the above-mentioned additive and the above-mentioned electrolyte is 14.0MPa 0.5 the following.

[0019] An electrode for a secondary battery is obtained by compression molding the electrode composition.

[0020] A secondary battery comprises the above-mentioned electrode for a secondary battery.

[0021] A secondary battery comprising a current collector layer, a secondary battery electrode layer and a separator layer, wherein the secondary battery satisfies all of the following conditions (1) to (4): (1) the secondary battery electrode layer contains an active material, an electrolyte and an additive, but does not contain a binder resin; (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 Below; (3) the HSP distance (Ra_Elec) between the above-mentioned additive and the above-mentioned electrolyte is 14.0MPa 0.5 (4) the weight average molecular weight (Mw) of the above-mentioned additive is 50,000 or less.

[0022] A secondary battery comprising a current collector layer, a secondary battery electrode layer and a separator layer, wherein the secondary battery satisfies all of the following conditions (1) to (3): (1) the secondary battery electrode layer contains an active material, an electrolyte, a binder resin and an additive; (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa 0.5 Below; (3) the HSP distance (Ra_Elec) between the above-mentioned additive and the above-mentioned electrolyte is 14.0MPa 0.5 the following.

[0023] An electrolyte penetration method, which is a method for allowing an electrolyte to penetrate into an electrode composition, wherein the electrolyte penetration method satisfies all of the following conditions (1) to (4): (1) the electrode composition contains an active material and an additive, but does not contain a binder resin; (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa 0.5 Below; (3) the HSP distance (Ra_Elec) between the above-mentioned additive and the above-mentioned electrolyte is 14.0MPa 0.5 (4) the weight average molecular weight (Mw) of the above-mentioned additive is 50,000 or less.

[0024] An electrolyte penetration method, which is a method for allowing an electrolyte to penetrate into an electrode composition, wherein the electrolyte penetration method satisfies all of the following conditions (1) to (3): (1) the electrode composition contains an active material, a binder resin and an additive; (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa 0.5 Below; (3) the HSP distance (Ra_Elec) between the above-mentioned additive and the above-mentioned electrolyte is 14.0MPa 0.5 the following.

[0025] A method for manufacturing a secondary battery, comprising the following steps: allowing an electrolyte to penetrate into a battery cell comprising a current collector layer, an electrode composition layer and a separator layer, thereby obtaining a secondary battery electrode layer containing the electrolyte in the electrode composition layer, wherein the method for manufacturing a secondary battery satisfies all of the following conditions (1) to (4): (1) the electrode composition layer contains an active material and an additive, but does not contain a binder resin; (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 Below; (3) the HSP distance (Ra_Elec) between the above-mentioned additive and the above-mentioned electrolyte is 14.0MPa 0.5 (4) the weight average molecular weight (Mw) of the above-mentioned additive is 50,000 or less.

[0026] A method for manufacturing a secondary battery, comprising the following steps: allowing an electrolyte to penetrate into a battery cell comprising a current collector layer, an electrode composition layer and a separator layer, thereby obtaining a secondary battery electrode layer containing the electrolyte in the electrode composition layer, wherein the method for manufacturing a secondary battery satisfies all of the following conditions (1) to (3): (1) the electrode composition layer contains an active material, a binder resin and an additive; (2) the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 Below; (3) the HSP distance (Ra_Elec) between the above-mentioned additive and the above-mentioned electrolyte is 14.0MPa 0.5 the following.

[0027] Effects of the Invention

[0028] According to the present invention, an electrode composition capable of producing an electrode having excellent electrolyte permeability can be provided. DETAILED DESCRIPTION

[0029] [Electrode composition]

[0030] The electrode composition of the present invention includes a first embodiment and a second embodiment.

[0031] The electrode composition of the first embodiment is an electrode composition for a secondary battery electrode layer comprising an electrolyte solution, and is an electrode composition that satisfies all of the following conditions (1) to (4).

[0032] (1) Contains active substances and additives but does not contain binder resin;

[0033] (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa 0.5 the following;

[0034] (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa 0.5 the following;

[0035] (4) The weight average molecular weight (Mw) of the above additive is 50,000 or less.

[0036] The electrode composition of the second embodiment is an electrode composition for a secondary battery electrode layer containing an electrolyte solution, and is an electrode composition that satisfies all of the following conditions (1) to (3).

[0037] (1) Containing active substances, binder resins and additives;

[0038] (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa 0.5 the following;

[0039] (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa 0.5 the following.

[0040] The electrode composition of the first embodiment differs from the electrode composition of the second embodiment in the following points, and the other points are the same.

[0041] The electrode composition of the first embodiment does not contain a binder resin in (1). The electrode composition of the second embodiment contains a binder resin in (1).

[0042] The electrode composition of the first embodiment stipulates that the weight average molecular weight (Mw) of the additive (4) is 50,000 or less, but the electrode composition of the second embodiment does not meet this requirement.

[0043] Hereinafter, the same matters in the electrode compositions of the first embodiment and the second embodiment will be described.

[0044] The electrode composition of the present invention is an electrode composition for a secondary battery electrode layer containing an electrolyte. The electrode composition of the present invention itself does not contain an electrolyte, but can be used as a secondary battery electrode layer by adding an electrolyte to the electrode composition.

[0045] The electrode composition contains an active material and additives.

[0046] (Active substance)

[0047] The active material may be a positive electrode active material or a negative electrode active material.

[0048] Examples of the positive electrode active material include composite oxides of lithium and transition metals {composite oxides containing one transition metal (LiCoO 2 、LiNiO 2 、LiAlMnO 4 、LiMnO 2 and LiMn 2 O 4 etc.), composite oxides with two transition metal elements (e.g. LiFeMnO 4 、LiNi 1-x Co x O 2 、LiMn 1-y Co y O 2 、LiNi 1 / 3 Co 1 / 3 Al 1 / 3 O 2 and LiNi 0.8 Co 0.15 Al0.05 O 2 ) and transition metal elements are three or more composite oxides [such as LiM a M' b M” c O 2 (M, M' and M" are different transition metal elements and satisfy a+b+c=1. For example, LiNi 0.8 Co 0.1 Mn 0.1 O 2 、LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O 2 ) etc., transition metal phosphates containing lithium (e.g. LiFePO 4 、LiCoPO 4 、LiMnPO 4 and LiNiPO 4 ), transition metal oxides (such as MnO 2 and V 2 O 5 ), transition metal sulfides (such as MoS 2 and TiS 2 ) and conductive polymers (such as polyaniline, polypyrrole, polythiophene, polyacetylene, polyparaphenylene and polyvinylcarbazole), etc., or two or more thereof may be used in combination.

[0049] It should be noted that the lithium-containing transition metal phosphate may be a phosphate in which a part of the transition metal sites are replaced with other transition metals.

[0050] Examples of the negative electrode active material include carbon materials [graphite (graphite, artificial graphite, natural graphite), non-graphitizable carbon (hard carbon), amorphous carbon, resin sintered bodies (e.g., phenolic resin and furan resin, etc., sintered and carbonized materials, etc.); cokes (e.g., pitch coke, needle coke, petroleum coke, etc.) and carbon fibers, etc.), silicon materials [silicon, silicon oxide (SiO x ), silicon-carbon composites (substances formed by coating the surface of carbon particles with silicon and / or silicon carbide, substances formed by coating the surface of silicon particles or silicon oxide particles with carbon and / or silicon carbide, and silicon carbide, etc.), and silicon alloys (silicon-aluminum alloys, silicon-lithium alloys, silicon-nickel alloys, silicon-iron alloys, silicon-titanium alloys, silicon-manganese alloys, silicon-copper alloys, and silicon-tin alloys, etc.), conductive polymers (such as polyacetylene and polypyrrole, etc.), metals (tin, aluminum, zirconium, and titanium, etc.), metal oxides (titanium oxide and lithium titanium oxide, etc.), and metal alloys (such as lithium-tin alloys, lithium-aluminum alloys, and lithium-aluminum-manganese alloys, etc.), and mixtures thereof with carbon-based materials, etc.

[0051] When the electrode active material is a negative electrode active material, artificial graphite or natural graphite is preferred as the negative electrode active material. When the negative electrode active material is graphite, the shape is not particularly limited, and examples thereof include spherical graphite and flaky graphite.

[0052] The content of the active material in the electrode composition is not particularly limited, but from the viewpoint of increasing the electrode density and the battery capacity, the content of the active material is preferably high, preferably 90% by weight to 95% by weight.

[0053] (additive)

[0054] The additive is a compound that satisfies the following conditions.

[0055] (2) The HSP distance between the additive and the active substance (Ra_Act) is 12.0 MPa 0.5 the following.

[0056] (3) The HSP distance between the additive and the electrolyte (Ra_Elec) is 14.0 MPa 0.5 the following.

[0057] The electrode composition of the first embodiment further satisfies the requirement "(4) the weight average molecular weight (Mw) of the additive is 50,000 or less." This point will be described below.

[0058] The HSP distance is determined from the Hansen solubility parameters (HSP values) of two substances for which the HSP distance is to be determined.

[0059] The HSP value is an index obtained by splitting the Hildebrand solubility parameter (SP value) into three components: dispersion component δD, polar component δP, and hydrogen bonding component δH, and taking into account the polarity of the physical property. 2 =δD 2 +δP 2 +δH 2 ” relationship.

[0060] The HSP distance between two substances is expressed by the following equation, where δD, δP, and δH of the two substances are respectively (δD1, δP1, δH1) and (δD2, δP2, δH2).

[0061] HSP distance = SQRT(4×(δD1-δD2) 2 +(δP1-δP2) 2 +(δH1-δH2) 2 )

[0062] The HSP distance refers to the distance between two points when the HSP value is considered as a coordinate in a three-dimensional space, and the smaller the HSP distance (the closer the HSP value), the easier it is for two substances to dissolve.

[0063] The HSP value of a substance can be calculated by inputting the structural formula into HSPiP (Hansen Solubility Parameters in Practice software).

[0064] Alternatively, numerical values ​​from the HSPiP database or literature values ​​may be used.

[0065] In addition to these methods, the HSP value can also be obtained through experiments.

[0066] The target component is dispersed in a solvent with a known HSP value, and the dispersibility of the component in a specific solvent is evaluated. For the evaluation of dispersibility, the target component to be determined for HSP is dispersed in a solvent, and the absorption spectrum is measured. The absorbance value for 20 minutes is recorded at intervals of 10 seconds (measurement wavelength: 632nm), and the absorbance after 20 minutes / absorbance at the start of measurement is calculated as the dispersion index DISP. The obtained dispersion index is used to evaluate the dispersibility in each solvent based on the following evaluation criteria.

[0067] 1: DISP=0.30 or more

[0068] 2: DISP = 0.20 or more and less than 0.30

[0069] 3: DISP = 0.15 or more and less than 0.20

[0070] 4: DISP = 0.10 or more and less than 0.15

[0071] 5: DISP = less than 0.10

[0072] The HSP value of the target component can be calculated by inputting the evaluation results of the dispersibility in each solvent into HSPiP.

[0073] As the solvent used in the method for obtaining the HSP value, any solvent such as toluene, N-methylpyrrolidone (NMP), diethyl carbonate, dimethylformamide, 1,4-dioxane, hexane, cyclohexane, methanol, ethanol, acetone, acetonitrile, and methyl ethyl ketone (MEK) can be used.

[0074] The HSP values ​​of the active material and the additive constituting the electrode composition are determined, and the HSP distance between the additive and the active material is determined from the HSP values ​​(specifically, δD, δP, and δH of the active material and the additive, respectively).

[0075] In the electrode composition of the present invention, the HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa 0.5 the following.

[0076] In addition, the HSP distance between the additive and the active material is preferably 4.0 MPa. 0.5 above.

[0077] The HSP distance between additives and active substances is less than 4.0MPa 0.5 In the case where the HSP distance between the additive and the active material is close, the compatibility between the additive and the active material is high, so the surface of the active material is corroded by the additive, and when the electrode layer is made, the electrode layer sometimes becomes brittle.

[0078] Although the electrolyte is not part of the composition of the electrode composition, the electrode composition contains the electrolyte and is used as an electrode layer of a secondary battery. The HSP distance between the additive and the electrolyte is determined by the relationship with the electrolyte contained in the electrode composition.

[0079] The HSP values ​​of the additive and the electrolyte are determined, and the HSP distance between the additive and the electrolyte is determined from the HSP values ​​(more precisely, δD, δP, and δH of the additive and the electrolyte, respectively).

[0080] In the electrode composition of the present invention, the (Ra_Elec) of the additive and the electrolyte is 14.0MPa 0.5 the following.

[0081] In addition, the HSP distance between the additive and the electrolyte is preferably 12.0 MPa. 0.5 the following.

[0082] The lower limit of the HSP distance between the additive and the electrolyte is not particularly limited, but is preferably 1.0 MPa. 0.5 above.

[0083] The additive is not particularly limited as long as it is a compound that satisfies conditions (2) and (3) regarding the HSP distance, and specific examples thereof include the following compounds.

[0084] (A1) Alkylene oxide adducts of alkyl alcohols

[0085] (A2) Alkylene glycol alkylene oxide adduct

[0086] (A3) Glycol ethers

[0087] (A4) Alkylene oxide adducts of bisphenols

[0088] (A5) Ester compound

[0089] (A6) Amine compound

[0090] (A7) Alcohol

[0091] (A1) Alkylene oxide adducts of alkyl alcohols

[0092] The alkylene oxide preferably contains ethylene oxide. In addition, the alkylene oxide may contain alkylene oxides other than ethylene oxide. Examples of alkylene oxides other than ethylene oxide include propylene oxide and butylene oxide.

[0093] In the present specification, alkylene oxide may be hereinafter referred to as AO, ethylene oxide may be hereinafter referred to as EO, propylene oxide may be hereinafter referred to as PO, and butylene oxide may be hereinafter referred to as BO.

[0094] The alkylene oxide may be a combination of ethylene oxide and propylene oxide, a combination of ethylene oxide and butylene oxide, or a combination of ethylene oxide, propylene oxide and butylene oxide.

[0095] When the alkylene oxide is composed of a plurality of types of alkylene oxides, the addition form may be random addition or block addition.

[0096] The molar ratio of ethylene oxide in the alkylene oxide is preferably 85% or more based on the total molar number of the alkylene oxide.

[0097] In addition, the alkylene oxide may be only ethylene oxide. That is, the molar ratio of ethylene oxide in the alkylene oxide may be 100% based on the total molar number of the alkylene oxide.

[0098] The molar ratio of ethylene oxide in the alkylene oxide may be 85 to 100%, 87 to 100%, 92 to 100%, 85 to 87%, 85 to 92%, or 87 to 92%.

[0099] It is preferable that the average added mole number of the alkylene oxide in the alkylene oxide adduct of alkyl alcohol is 2-40.

[0100] The average number of moles of alkylene oxide added may be 3-20, or 4-10.

[0101] When a plurality of alkylene oxides are present, the number of moles of alkylene oxide added is the total number of moles of alkylene oxide added.

[0102] The alkyl alcohol constituting the alkylene oxide adduct of the alkyl alcohol is preferably a saturated alkyl alcohol from the viewpoint of suppressing degradation of battery performance due to a side reaction that may occur during charge and discharge.

[0103] The alkyl group of the alkyl alcohol may be a linear chain or a branched chain.

[0104] The number of carbon atoms in the alkyl group of the alkyl alcohol is not particularly limited, but is preferably 1 to 20.

[0105] Examples of the alkyl alcohol having 1 to 20 carbon atoms include methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, 2-ethylhexanol, isodecyl alcohol, and isotridecanol.

[0106] Specific examples of the alkylene oxide adducts of alkyl alcohols include heptaethylene glycol monoisodecyl ether, tetraethylene glycol monopentadecyl ether, nonaethylene glycol monododecyl ether, nonaethylene glycol monomethyl ether, and the like.

[0107] (A2) Alkylene glycol alkylene oxide adduct

[0108] As the alkylene oxide, the same alkylene oxide as in (A1) can be used, and the form and combination of addition of the alkylene oxide can also be the same as in (A1).

[0109] The molar ratio of ethylene oxide in the alkylene oxide is preferably 85% or more based on the total molar number of the alkylene oxide.

[0110] In addition, the alkylene oxide may be only ethylene oxide. That is, the molar ratio of ethylene oxide in the alkylene oxide may be 100% based on the total molar number of the alkylene oxide.

[0111] The alkylene glycol is preferably ethylene glycol, and preferably an ethylene oxide adduct (polyethylene glycol) of ethylene glycol.

[0112] It is preferable that the average added mole number of the alkylene oxide in the alkylene oxide adduct of alkylene glycol is 2-40.

[0113] The average number of moles of alkylene oxide added may be 3-20, or 4-10.

[0114] Specific examples of the alkylene glycol alkylene oxide adduct include tetraethylene glycol (the number of moles of ethylene oxide added is 4), octaethylene glycol (the number of moles of ethylene oxide added is 8), and heptapropylene glycol (the number of moles of propylene oxide added is 7).

[0115] (A3) Glycol ethers

[0116] As the alkylene glycol unit in the glycol ether, ethylene glycol and propylene glycol are preferred, and ethylene glycol is more preferred. The number of repetitions of the alkylene glycol unit is preferably 3 to 20, and may be 4 to 15.

[0117] Specific examples of the glycol ethers include triethylene glycol dimethyl ether, hexaethylene glycol tribenzyl phenyl ether, tetradecaethylene glycol tribenzyl phenyl ether, and the like.

[0118] (A4) Alkylene oxide adducts of bisphenols

[0119] This is a compound obtained by adding an alkylene oxide to a bisphenol. As the alkylene oxide, the same alkylene oxide as (A1) can be used, and the form and combination of the alkylene oxide addition can also be the same as (A1).

[0120] For example, EO adducts of bisphenol A, PO adducts of bisphenol A, and BO adducts of bisphenol A are mentioned.

[0121] The average number of moles of the alkylene oxide added may be 1-20, or 1-5.

[0122] Specific examples of the alkylene oxide adducts of bisphenols include EO 2 mol adducts of bisphenol A and the like.

[0123] (A5) Ester compound

[0124] It includes carboxylic acid esters, phosphoric acid esters and the like, and examples thereof include monoesters, diesters and triesters.

[0125] Specific examples of the ester compound include methyl n-octanoate, methyl myristate, glyceryl stearate, and triester phosphate (tris(2-chloro-1-methylethyl)phosphate, etc.).

[0126] (A6) Amine compound

[0127] Examples thereof include saturated cyclic monoamines [e.g., alicyclic amines (monoamines containing a cyclic saturated hydrocarbon group) {e.g., cyclobutylamine, cyclopentylamine, cyclohexylamine, cycloheptylamine, dicyclohexylamine, N-methylcyclohexylamine, trimethylcyclohexylamine, aminomethylcyclohexane, 1-cyclohexylethylamine, etc.}, saturated heterocyclic monoamines {e.g., morpholine, piperidine, etc.}, etc.], unsaturated cyclic monoamines (monoamines containing a cyclic unsaturated hydrocarbon group) [e.g., aromatic amines {e.g., aniline, anisidine, toluidine, trimethylaniline, etc.}, unsaturated heterocyclic monoamines {e.g., pyrrole, azepine, azacyclononatetraene, etc.}, etc.], etc.

[0128] Among them, cyclohexylamine is preferred.

[0129] (A7) Alcohol

[0130] Examples include aliphatic alcohols, aromatic alcohols, and aromatic aliphatic alcohols. Aliphatic alcohols are preferred. The number of carbon atoms in the aliphatic group is not particularly limited and may be 1 to 20, or 10 to 20.

[0131] A specific example of alcohol is hexadecanol.

[0132] The content of the additive is preferably 0.001 to 2% by weight based on the weight of the electrode composition. When the content of the additive is within this range, the effect of the additive can be more appropriately exhibited.

[0133] (Electrolyte)

[0134] As the electrolyte solution, an electrolyte solution for secondary batteries can be used, and preferably an electrolyte solution containing a non-aqueous solvent that can be used for lithium ion batteries can be used.

[0135] The HSP distance (Ra_Elec) between the electrolyte and the additives contained in the electrode composition is 14.0 MPa 0.5 The following electrolyte.

[0136] As the solvent contained in the electrolyte, a non-aqueous solvent used as a solvent in a known electrolyte can be used, and for example, lactone compounds, cyclic or chain carbonates, chain carboxylates, cyclic or chain ethers, phosphates, nitrile compounds, amide compounds, sulfones, cyclopentane sulfones and mixtures thereof can be used.

[0137] Examples of the lactone compound include lactone compounds having a 5-membered ring (γ-butyrolactone, γ-valerolactone, etc.) and a 6-membered ring (δ-valerolactone, etc.).

[0138] Examples of the cyclic carbonate include propylene carbonate (PC), ethylene carbonate (EC), and butylene carbonate (BC).

[0139] Examples of the chain carbonate include dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), methyl n-propyl carbonate, ethyl n-propyl carbonate, and di-n-propyl carbonate.

[0140] Examples of the chain carboxylic acid ester include methyl acetate, ethyl acetate, propyl acetate, and methyl propionate.

[0141] Examples of the cyclic ether include tetrahydrofuran, tetrahydropyran, 1,3-dioxolane, and 1,4-dioxane, and examples of the chain ether include dimethoxymethane and 1,2-dimethoxyethane.

[0142] Examples of the phosphoric acid ester include trimethyl phosphate, triethyl phosphate, ethyl dimethyl phosphate, diethyl methyl phosphate, tripropyl phosphate, tributyl phosphate, tris(trifluoromethyl) phosphate, tris(trichloromethyl) phosphate, tris(trifluoroethyl) phosphate, 2-ethoxy-1,3,2-dioxaphospholane-2-one, 2-trifluoroethoxy-1,3,2-dioxaphospholane-2-one, and 2-methoxyethoxy-1,3,2-dioxaphospholane-2-one.

[0143] Examples of the nitrile compound include acetonitrile, etc. Examples of the amide compound include DMF, etc. Examples of the sulfone include dimethyl sulfone and diethyl sulfone, etc.

[0144] These solvents may be used alone or in combination of two or more.

[0145] The mixed solvent is preferably a mixed solvent of ethylene carbonate and diethyl carbonate; a mixed solvent of ethylene carbonate, ethyl methyl carbonate and diethyl carbonate; or a mixed solvent of ethylene carbonate and propylene carbonate.

[0146] As the electrolyte contained in the electrolytic solution, an electrolyte used in a known electrolytic solution can be used, and examples thereof include LiPF 6 , LiBF 4 、LiSbF 6 、LiAsF 6 、LiClO 4 and LiN(FSO 2 ) 2 Lithium salts of inorganic anions such as LiN(CF 3 SO 2 ) 2 、LiN(C 2 F 5 SO 2 ) 2 and LiC(CF 3 SO 2 ) 3 Among them, LiPF 6 (lithium hexafluorophosphate), LiFSI (lithium bis(fluorosulfonyl)imide), etc.

[0147] The concentration of the electrolyte in the electrolytic solution is not particularly limited, but is preferably 0.3 to 5.0 mol / L, more preferably 0.5 to 2.0 mol / L, and even more preferably 0.8 to 1.5 mol / L.

[0148] The HSP value of the electrolyte solution basically depends on the type of solvent, and the HSP value can be determined based on the type of solvent without considering the influence of the electrolyte.

[0149] When a mixed solvent is used as the solvent, the average values ​​of the components (δD, δP, and δH) of the HSP values ​​of the respective solvents obtained based on the volume ratios of the respective solvents are used as the components of the HSP value of the mixed solvent.

[0150] (Binder resin)

[0151] The electrode composition of the first embodiment does not contain a binder resin, and the electrode composition of the second embodiment contains a binder resin. The binder resin will be described below.

[0152] Substances that can be used as additives may include substances known as binder resins, but in this specification, binder resins are regarded as substances distinguished from additives.

[0153] The binder resin is a resin used in lithium ion batteries, and examples thereof include starch, polyvinylidene fluoride, polyvinyl alcohol, polyvinyl pyrrolidone, polytetrafluoroethylene, styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC), polyethylene, and polypropylene.

[0154] In the case where the electrode composition contains these substances, they are regarded as being contained as a binder resin.

[0155] Even if the relationship between the HSP distance with the active material and the HSP distance with the electrolyte satisfies the definition of the present invention, these substances are not included in the additives of the present invention.

[0156] In addition, the weight average molecular weight (Mw) of the binder resin often exceeds 50,000. In view of this, the electrode composition of the first embodiment not containing a binder resin satisfies the condition of "(4) the weight average molecular weight (Mw) of the additive is 50,000 or less".

[0157] The weight average molecular weight of the additive may be a molecular weight determined based on the structural formula of the additive. When determined by measurement, it can be measured by gel permeation chromatography under the following conditions, for example.

[0158] Device: "Waters Alliance 2695" [manufactured by Waters]

[0159] Column: "Guardcolumn Super HL" (1 column), "column formed by connecting 1 each of TSKgel SuperH2000, TSKgelSuperH3000, and TSKgel SuperH4000 (all manufactured by Tosoh Corporation)"

[0160] Sample solution: 0.25 wt% tetrahydrofuran solution

[0161] Solution injection volume: 10μl

[0162] Flow rate: 0.6ml / min

[0163] Measurement temperature: 40℃

[0164] Detection device: Refractive index detector

[0165] Reference material: Standard polyethylene glycol

[0166] On the other hand, since the electrode composition of the second embodiment is specified to contain a binder resin, it may contain a substance having a weight average molecular weight exceeding 50,000.

[0167] When the electrode composition contains a binder resin, the content of the binder resin is preferably more than 0% by weight and not more than 6.0% by weight based on the weight of the electrode composition.

[0168] The electrode composition of the present invention may contain a conductive aid. Examples of the conductive aid include metals [aluminum, stainless steel (SUS), silver, gold, copper, titanium, etc.], carbon [graphite (flaky graphite (UP)), carbon black (acetylene black, Ketjen black, furnace black, channel black, hot lamp black, etc.) and carbon nanofibers (CNF)], and mixtures thereof.

[0169] As the conductive auxiliary agent, acetylene black is preferred.

[0170] It should be noted that carbon-based materials are used both as negative electrode active materials and as conductive aids, but in this application, materials with a volume average particle size of 10.0 μm or more are regarded as negative electrode active materials, and materials with a volume average particle size of less than 10.0 μm are regarded as conductive aids.

[0171] The electrode composition of the present invention has a HSP distance of 12.0 MPa between the active material and the additive. 0.5 The following is the result of good fusion of the active material and the additive, and the surface of the active material is treated by the additive. In addition, the HSP distance between the additive and the electrolyte is set to 14.0 MPa. 0.5 The additive and the electrolyte are well integrated. Therefore, the electrolyte easily permeates into the electrode composition. Therefore, the electrode composition of the present invention is an electrode composition capable of manufacturing an electrode having excellent electrolyte permeability.

[0172] Furthermore, the electrode composition of the present invention is excellent in electrolyte permeability even when the electrode density is increased, and thus is an electrode composition capable of producing an electrode with a high energy density without reducing productivity.

[0173] In addition, if the HSP distance between the active substance and the additive is 4.0 MPa 0.5 As described above, an electrode composition capable of producing an electrode having excellent characteristics also from the viewpoint of electrode brittleness can be obtained.

[0174] [Secondary battery electrode and secondary battery]

[0175] The secondary battery electrode of the present invention is obtained by compression molding the electrode composition of the present invention.

[0176] As the electrode composition of the present invention, any of the electrode composition of the first embodiment and the electrode composition of the second embodiment can be used.

[0177] The method for compression molding the electrode composition is not particularly limited, and methods such as roll pressing and pressing with a press machine can be used. The electrode density of the secondary battery electrode obtained by compression molding the electrode composition is preferably 1.0 to 2.0 g / cm 3 .

[0178] The electrode density specified here refers to the density in a state where the electrolyte is not allowed to permeate into the electrode composition.

[0179] In addition, a secondary battery including the secondary battery electrode of the present invention described above is also a secondary battery of the present invention. In the secondary battery of the present invention, the configuration other than the secondary battery electrode of the present invention is not particularly limited.

[0180] [Secondary battery]

[0181] The secondary battery of the present invention includes, in addition to the secondary battery including the secondary battery electrode of the present invention described above, the following first embodiment and second embodiment of the secondary battery.

[0182] The secondary battery of the first embodiment corresponds to the electrode composition of the first embodiment, and the secondary battery of the second embodiment corresponds to the electrode composition of the second embodiment.

[0183] The secondary battery of the first embodiment is a secondary battery including a current collector layer, a secondary battery electrode layer, and a separator layer, and is a secondary battery that satisfies all of the following conditions (1) to (4).

[0184] (1) The secondary battery electrode layer contains an active material, an electrolyte and an additive, but does not contain a binder resin;

[0185] (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa 0.5 the following;

[0186] (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa 0.5 the following;

[0187] (4) The weight average molecular weight (Mw) of the above additive is 50,000 or less.

[0188] The secondary battery of the second embodiment is a secondary battery including a current collector layer, a secondary battery electrode layer, and a separator layer, and is a secondary battery that satisfies all of the following conditions (1) to (3).

[0189] (1) The secondary battery electrode layer contains an active material, an electrolyte, a binder resin and an additive;

[0190] (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa 0.5 the following;

[0191] (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa0.5 the following.

[0192] The provisions of (2) to (4) in the secondary batteries of the first and second aspects are the same as the provisions of (2) to (4) in the electrode composition of the present invention.

[0193] The secondary battery of the first aspect and the second aspect includes a secondary battery electrode layer. In (1), it is defined that the secondary battery electrode layer contains an electrolyte solution.

[0194] The secondary battery electrode layer is a layer formed by making the electrode composition of the first mode and the second mode contain an electrolyte. The secondary battery electrode layer has good electrolyte permeability to the electrode composition of the first mode and the second mode, so it can contain a sufficient amount of electrolyte in a short time. Since the secondary battery electrode layer can contain a sufficient amount of electrolyte in a short time, the secondary battery of the first mode and the second mode becomes a secondary battery that requires a short manufacturing time and can extract a capacity close to the theoretical value.

[0195] The components of the secondary battery other than the secondary battery electrode layer include a current collector layer and a separator layer. As the current collector layer and the separator layer, current collectors and separators that can be used for ordinary lithium ion secondary batteries can be used.

[0196] The secondary battery of the present invention can be used as a secondary battery used in mobile phones, personal computers, hybrid vehicles, electric vehicles, stationary power supplies, and the like.

[0197] [Electrolyte penetration method]

[0198] The electrolyte permeation method of the present invention includes the following first embodiment and second embodiment.

[0199] The electrolyte solution permeation method of the first embodiment corresponds to a method of allowing the electrolyte solution to permeate into the electrode composition of the first embodiment, and the electrolyte solution permeation method of the second embodiment corresponds to a method of allowing the electrolyte solution to permeate into the electrode composition of the second embodiment.

[0200] The electrolyte solution permeation method of the first embodiment is a method of permeating the electrolyte solution into the electrode composition, and is an electrolyte solution permeation method that satisfies all of the following conditions (1) to (4).

[0201] (1) The electrode composition contains an active material and an additive, but does not contain a binder resin;

[0202] (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa 0.5 the following;

[0203] (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa 0.5 the following;

[0204] (4) The weight average molecular weight (Mw) of the above additive is 50,000 or less.

[0205] The electrolyte solution permeation method of the second embodiment is a method of permeating the electrolyte solution into the electrode composition, and is an electrolyte solution permeation method that satisfies all of the following conditions (1) to (3).

[0206] (1) The electrode composition contains an active material, a binder resin and an additive;

[0207] (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa 0.5 the following;

[0208] (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa 0.5 the following.

[0209] In any of the electrolyte infiltration methods, the means for infiltrating the electrolyte into the electrode composition is not particularly limited, and any of a spray coater, a dispenser, a die coater, and a roll coater may be used.

[0210] Alternatively, after assembling battery components such as an electrode composition, a current collector, and a separator and sealing with a sealing member, the electrolyte may be injected into the electrode composition from an injection port provided in the sealing member to allow the electrolyte to permeate into the electrode composition.

[0211] In the electrolyte permeation method of the present invention, since the electrolyte permeability to the electrode composition is good, the operation of permeating the electrolyte into the electrode composition can be performed in a short time, and the workability when obtaining the secondary battery electrode layer is good.

[0212] The time required to allow the electrolyte to permeate into the electrode composition (permeation time) varies depending on the type of the electrolyte, the size of the secondary battery, etc., but may be, for example, 300 minutes or less.

[0213] [Method for producing secondary battery]

[0214] The method for producing a secondary battery of the present invention includes the following first embodiment and second embodiment of the method for producing a secondary battery.

[0215] The first embodiment of the secondary battery manufacturing method corresponds to a method of manufacturing a secondary battery by allowing an electrolyte to permeate into the first embodiment of the electrode composition, and the second embodiment of the electrolyte permeation method corresponds to a method of manufacturing a secondary battery by allowing an electrolyte to permeate into the second embodiment of the electrode composition.

[0216] The first method for manufacturing a secondary battery comprises the following steps: allowing an electrolyte to penetrate into a battery cell comprising a current collector layer, an electrode composition layer and a separator layer, thereby obtaining a secondary battery electrode layer containing the electrolyte in the electrode composition layer, wherein the method for manufacturing a secondary battery satisfies all of the following conditions (1) to (4).

[0217] (1) The electrode composition layer contains active materials and additives but does not contain a binder resin;

[0218] (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa 0.5 the following;

[0219] (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa 0.5 the following;

[0220] (4) The weight average molecular weight (Mw) of the above additive is 50,000 or less.

[0221] The second method for manufacturing a secondary battery comprises the following steps: allowing an electrolyte to penetrate into a battery cell comprising a current collector layer, an electrode composition layer and a separator layer, thereby obtaining a secondary battery electrode layer containing the electrolyte in the electrode composition layer, wherein the method for manufacturing a secondary battery satisfies all of the following conditions (1) to (3).

[0222] (1) The electrode composition layer contains an active material, a binder resin and an additive;

[0223] (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa 0.5 the following;

[0224] (3) The HSP distance (Ra_Elec) between the additive and the electrolyte is 14.0 MPa 0.5 the following.

[0225] In any of the secondary battery production methods, the means for allowing the electrolyte to penetrate into the battery cell including the electrode composition layer is not particularly limited, and any of a spray coater, a dispenser, a die coater, and a roll coater may be used.

[0226] When the electrolyte is infiltrated into the battery cell, the electrolyte can be infiltrated into the electrode composition to form a secondary battery electrode layer, and then the collector layer and the separator layer can be combined to form a battery cell with a secondary battery electrode layer. Alternatively, after the collector layer, the electrode composition layer and the separator layer are combined, the electrolyte can be infiltrated into the electrode composition layer to form a secondary battery electrode layer, and a battery cell with a secondary battery electrode layer can be formed.

[0227] In the method for producing a secondary battery of the present invention, since the electrolyte permeability to the electrode composition is good, the operation of allowing the electrolyte to permeate into the electrode composition can be performed in a short time, and the workability when obtaining the secondary battery electrode layer is good.

[0228] The time required to allow the electrolyte to permeate into the electrode composition (permeation time) varies depending on the type of the electrolyte, the size of the secondary battery, etc., but may be, for example, 300 minutes or less.

[0229] The following matters are disclosed in this specification.

[0230] The present disclosure (1) is an electrode composition for a secondary battery electrode layer containing an electrolyte, wherein the electrode composition satisfies all of the following conditions (1) to (4). (1) It contains an active material and an additive, but does not contain a binder resin; (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 (3) the HSP distance (Ra_Elec) between the above-mentioned additive and the above-mentioned electrolyte is 14.0MPa 0.5 (4) the weight average molecular weight (Mw) of the above-mentioned additive is 50,000 or less.

[0231] The present disclosure (2) is an electrode composition, which is an electrode composition for a secondary battery electrode layer containing an electrolyte, wherein the electrode composition satisfies all of the following conditions (1) to (3). (1) It contains an active material, a binder resin and an additive; (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 Below; (3) the HSP distance (Ra_Elec) between the above-mentioned additive and the above-mentioned electrolyte is 14.0MPa 0.5 the following.

[0232] The present disclosure (3) is the electrode composition described in the present disclosure (1) or (2), wherein the HSP distance (Ra_Act) between the additive and the active material is 4.0 MPa. 0.5 above.

[0233] The present disclosure (4) is the electrode composition according to any one of the present disclosures (1) to (3), wherein the HSP distance (Ra_Elec) between the additive and the electrolyte is 12.0 MPa. 0.5 the following.

[0234] The present disclosure (5) is the electrode composition according to any one of the present disclosures (1) to (4), wherein the additive is an alkylene oxide adduct of an alkyl alcohol or an alkylene oxide adduct of an alkylene glycol.

[0235] The present disclosure (6) is the electrode composition described in the present disclosure (5), wherein the alkyl alcohol is a saturated alkyl alcohol.

[0236] The present disclosure (7) is an electrode composition according to any one of the present disclosures (1) to (6), wherein the active material is at least one selected from the group consisting of a composite oxide containing at least one transition metal element, artificial graphite, and natural graphite.

[0237] The present disclosure (8) is an electrode composition as described in any one of the present disclosures (1) to (7), wherein the solvent of the above-mentioned electrolyte is a mixed solvent of ethylene carbonate and diethyl carbonate; a mixed solvent of ethylene carbonate, ethyl methyl carbonate and diethyl carbonate; or a mixed solvent of ethylene carbonate and propylene carbonate.

[0238] The present disclosure (9) is an electrode for a secondary battery, which is obtained by compression molding the electrode composition according to any one of the present disclosures (1) to (8).

[0239] The present disclosure (10) is a secondary battery comprising the secondary battery electrode described in the present disclosure (9).

[0240] The present disclosure (11) is a secondary battery comprising a current collector layer, a secondary battery electrode layer and a separator layer, wherein the secondary battery satisfies all of the following conditions (1) to (4). (1) The secondary battery electrode layer contains an active material, an electrolyte and an additive, but does not contain a binder resin; (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 Below; (3) the HSP distance (Ra_Elec) between the above-mentioned additive and the above-mentioned electrolyte is 14.0MPa 0.5 (4) the weight average molecular weight (Mw) of the above-mentioned additive is 50,000 or less.

[0241] The present disclosure (12) is a secondary battery comprising a current collector layer, a secondary battery electrode layer and a separator layer, wherein the secondary battery satisfies all of the following conditions (1) to (3). (1) The secondary battery electrode layer contains an active material, an electrolyte, a binder resin and an additive; (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 Below; (3) the HSP distance (Ra_Elec) between the above-mentioned additive and the above-mentioned electrolyte is 14.0MPa 0.5 the following.

[0242] The present disclosure (13) is an electrolyte penetration method, which is a method for allowing an electrolyte to penetrate into an electrode composition, wherein the electrolyte penetration method satisfies all of the following conditions (1) to (4). (1) The electrode composition contains an active material and an additive, but does not contain a binder resin; (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 Below; (3) the HSP distance (Ra_Elec) between the above-mentioned additive and the above-mentioned electrolyte is 14.0MPa 0.5 (4) the weight average molecular weight (Mw) of the above-mentioned additive is 50,000 or less.

[0243] The present disclosure (14) is an electrolyte penetration method, which is a method for allowing an electrolyte to penetrate into an electrode composition, wherein the electrolyte penetration method satisfies all of the following conditions (1) to (3). (1) The electrode composition contains an active material, a binder resin, and an additive; (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 Below; (3) the HSP distance (Ra_Elec) between the above-mentioned additive and the above-mentioned electrolyte is 14.0MPa 0.5 the following.

[0244] The present disclosure (15) is a method for manufacturing a secondary battery, which performs the following steps: allowing an electrolyte to penetrate into a battery cell comprising a current collector layer, an electrode composition layer, and a separator layer to obtain a secondary battery electrode layer containing the electrolyte in the electrode composition layer, wherein the method for manufacturing a secondary battery satisfies all of the following conditions (1) to (4). (1) The electrode composition layer contains an active material and an additive, but does not contain a binder resin; (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 Below; (3) the HSP distance (Ra_Elec) between the above-mentioned additive and the above-mentioned electrolyte is 14.0MPa 0.5 (4) the weight average molecular weight (Mw) of the above-mentioned additive is 50,000 or less.

[0245] The present disclosure (16) is a method for manufacturing a secondary battery, which performs the following steps: allowing an electrolyte to penetrate into a battery cell comprising a current collector layer, an electrode composition layer, and a separator layer, to obtain a secondary battery electrode layer containing the electrolyte in the electrode composition layer, wherein the method for manufacturing a secondary battery satisfies all of the following conditions (1) to (3). (1) The electrode composition layer contains an active material, a binder resin, and an additive; (2) The HSP distance (Ra_Act) between the additive and the active material is 12.0 MPa. 0.5 Below; (3) the HSP distance (Ra_Elec) between the above-mentioned additive and the above-mentioned electrolyte is 14.0MPa 0.5 the following.

[0246] Example

[0247] Next, the present invention will be specifically described by way of examples, but the present invention is not limited to the examples unless it deviates from the gist of the present invention. It should be noted that, unless otherwise specified, parts refer to parts by weight, and % refers to % by weight.

[0248] (Preparation of Additives 1 to 21)

[0249] The following additives 1 to 21 were prepared.

[0250] (Additive 1)

[0251] As additive 1, methyl n-octanoate (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used.

[0252] (Additive 2)

[0253] As the additive 2, methyl tetradecanoate (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used.

[0254] (Additive 3)

[0255] Glycerin and stearic acid (molar ratio: 1 / 1) were added to xylene to start the esterification reaction (xylene content was 50 wt% of the total). Polymerization was carried out while refluxing, and water generated in the esterification reaction was removed together with xylene. The reaction was continued while adding additional xylene until no more water was generated. After the reaction, xylene was removed using a reduced pressure dryer to obtain solid glyceryl stearate as additive 3.

[0256] (Additive 4)

[0257] As Additive 4, an alkylene oxide adduct of an alkyl alcohol produced by adding ethylene oxide (EO) to isodecyl alcohol was obtained.

[0258] The average number of added moles of EO is 7.0, and the compound is named heptaethylene glycol monoisodecyl ether.

[0259] (Additive 5)

[0260] As Additive 5, an alkylene oxide adduct of an alkyl alcohol produced by adding ethylene oxide (EO) to pentadecyl alcohol was obtained.

[0261] The average number of added moles of EO is 4.0, and the compound is named tetraethylene glycol monopentadecyl ether.

[0262] (Additive 6)

[0263] As Additive 6, an alkylene oxide adduct of an alkyl alcohol produced by adding ethylene oxide (EO) to dodecanol was obtained.

[0264] The average number of added moles of EO is 9.0, and the compound is named nonaethylene glycol monododecyl ether.

[0265] (Additive 7)

[0266] Tetraethylene glycol (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 7.

[0267] (Additive 8)

[0268] Octaethylene glycol (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 8.

[0269] (Additive 9)

[0270] As Additive 9, an alkylene oxide adduct of an alkyl alcohol produced by adding ethylene oxide (EO) to methanol was obtained.

[0271] The average number of added moles of EO is 9.0, and the compound is named nonaethylene glycol monomethyl ether.

[0272] (Additive 10)

[0273] As the additive 10, triethylene glycol dimethyl ether (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used.

[0274] (Additive 11)

[0275] As the additive 11, an alkylene oxide adduct of an alkyl alcohol produced by adding ethylene oxide (EO) to p-tribenzylphenol was obtained.

[0276] The average number of added moles of EO is 6.0, and the compound name is hexaethylene glycol tribenzyl phenyl ether.

[0277] (Additive 12)

[0278] As the additive 12, an alkylene oxide adduct of an alkyl alcohol produced by adding ethylene oxide (EO) to p-tribenzylphenol was obtained.

[0279] The average number of added moles of EO is 14.0, and the compound name is tetradecaethylene glycol tribenzyl phenyl ether.

[0280] (Additive 13)

[0281] Cyclohexylamine (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 13.

[0282] (Additive 14)

[0283] As the additive 14, an alkylene oxide adduct of an alkyl alcohol produced by adding ethylene oxide (EO) to bisphenol A was obtained.

[0284] The average number of moles of EO added is 2.0, and the compound name is bisphenol A EO 2 mole addition product.

[0285] (Additive 15)

[0286] Tris(2-chloro-1-methylethyl) phosphate (reagent: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was used as the additive 15 .

[0287] (Additive 16)

[0288] As the additive 16, an alkylene oxide adduct of an alkyl alcohol produced by adding propylene oxide (PO) to propylene glycol was obtained.

[0289] The average number of added moles of PO is 6.0, and the compound is named heptapropylene glycol.

[0290] (Additive 17)

[0291] Hexadecanol (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 17.

[0292] (Additive 18)

[0293] Triethylene glycol (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 18.

[0294] (Additive 19)

[0295] Ethylene glycol monomethyl ether (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as additive 19.

[0296] (Additive 20)

[0297] Trimethylolpropane (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the additive 20 .

[0298] (Additive 21)

[0299] As the additive 21, N-(hydroxymethyl)methacrylamide (reagent: manufactured by Tokyo Chemical Industry Co., Ltd.) was used.

[0300] (Preparation of electrolyte solutions 1 to 4)

[0301] All the materials prepared below were reagents (manufactured by Tokyo Chemical Industry Co., Ltd.).

[0302] (Electrolyte 1)

[0303] Ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed in a volume ratio of EC:DEC = 1:1 to dissolve lithium hexafluorophosphate (LIPF) in a 1M solution. 6 ), and the resulting solution is used as electrolyte 1.

[0304] (Electrolyte 2)

[0305] Ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) were mixed in a volume ratio of EC:EMC:DEC=2:4:4 to dissolve lithium hexafluorophosphate (LIPF) in a 1M solution. 6 ), and the resulting solution is used as electrolyte 2.

[0306] (Electrolyte 3)

[0307] Ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) were mixed in a volume ratio of EC:EMC:DEC=3:5:2 to dissolve lithium hexafluorophosphate (LIPF) in a 1M solution. 6 ), and the resulting solution is used as electrolyte 3.

[0308] (Electrolyte 4)

[0309] Ethylene carbonate (EC) and propylene carbonate (PC) were mixed in a volume ratio of EC:PC = 1:1 to dissolve lithium hexafluorophosphate (LIPF) in a 1M solution. 6 ), and the resulting solution is used as electrolyte 4.

[0310] (Preparation of negative electrode active material)

[0311] The following negative electrode active materials were prepared.

[0312] Graphite 1: Artificial graphite (FSN-1, manufactured by China Shanshan, volume average particle size (D50): 15.3 μm)

[0313] Graphite 2: Spherical graphite (CGR 12R, manufactured by Nippon Graphite Industries, Ltd., volume average particle size: 10.6 μm)

[0314] (Calculation of HSP value of negative electrode active material: graphite 1)

[0315] The dispersibility of Graphite 1 in various solvents was evaluated by the following method.

[0316] 20 mL of a solvent with known solubility parameters and 0.04 g of graphite 1 were placed in a No. 7 screw tube manufactured by Maruemu Co., Ltd., and a stirring bar was added and stirred at 400 rpm for 30 minutes to prepare a suspension, which was then left to stand in a thermostatic bath at 25° C. for 12 hours to prepare a dispersion for measurement.

[0317] Solvents with known solubility parameters are toluene, N-methylpyrrolidone (NMP), diethyl carbonate, dimethylformamide, 1,4-dioxane, hexane, cyclohexane, methanol, ethanol, acetone, acetonitrile, and methyl ethyl ketone (MEK).

[0318] The solubility parameters of these solvents were referenced from the HSPiP database.

[0319] In addition, only 20 mL of each solvent was taken into a No. 7 screw tube manufactured by Maruemu Co., Ltd. and allowed to stand in a thermostatic bath at 25° C. for 12 hours in the same manner to serve as a reference solvent.

[0320] Baseline determination was performed using a UV-visible-near infrared spectrophotometer (UV-3600i Plus, Shimadzu Corporation) with a reference solvent. Then, the dispersion corresponding to the reference solvent was stirred in a threaded tube for more than 1 minute, and in a fully dispersed state, 1000 μL was transferred to a quartz cell with a stirrer 4 times with a micropipette while stirring to serve as a measurement cell. The measurement cell was set on a stand with a stirrer, stirred for 30 seconds, and the absorption spectrum was measured while the stirring was stopped, and the absorbance value for 20 minutes was recorded at intervals of 10 seconds (measurement wavelength: 632 nm).

[0321] The dispersion index DISP was calculated as "absorbance after 20 minutes (A20) / absorbance at the start of measurement (A0)". The obtained dispersion index was used to evaluate the dispersibility in each solvent based on the following evaluation criteria.

[0322] (Evaluation Criteria)

[0323] 1: DISP=0.30 or above

[0324] 2: DISP = 0.20 or more and less than 0.30

[0325] 3: DISP = 0.15 or more and less than 0.20

[0326] 4: DISP = 0.10 or more and less than 0.15

[0327] 5: DISP = less than 0.10

[0328] The HSP value of Graphite 1 was calculated by inputting HSPiP from the evaluation results of the dispersibility of Graphite 1 in the solvent. Table 1 shows the evaluation results of the dispersibility used for calculating the HSP value of Graphite 1.

[0329] [Table 1]

[0330] Type of solvent δD δP δH DISP evaluate Toluene 18.0 1.4 2.0 0.33 1 N-Methylpyrrolidone (NMP) 18.0 12.3 7.2 0.31 1 Diethyl carbonate 15.1 6.3 3.5 0.15 3 dimethylformamide 17.4 13.7 11.3 0.15 3 1,4-Dioxane 17.5 1.8 9.0 0.12 4 Hexane 14.9 0.0 0.0 0.12 4 Cyclohexane 16.8 0.0 0.2 0.11 4 Methanol 14.7 12.3 22.3 0.11 4 Ethanol 15.8 8.8 19.4 0.09 5 acetone 15.5 10.4 7.0 0.07 5 Acetonitrile 15.3 18.0 6.1 0.07 5 Methyl Ethyl Ketone (MEK) 16.0 9.0 5.1 0.04 5

[0331] (Calculation of HSP value of negative electrode active material: graphite 2)

[0332] The HSP value of Graphite 2 was calculated in the same manner as Graphite 1. In the calculation of the HSP value of Graphite 1, hexane, which is a solvent with known solubility parameters, was used instead of another solvent. The other steps were the same as those of Graphite 1.

[0333] Table 2 shows the evaluation results of the dispersibility used for calculating the HSP value of Graphite 2.

[0334] [Table 2]

[0335] Type of solvent δD δP δH DISP evaluate Toluene 18.0 1.4 2.0 0.54 1 Cyclohexane 16.8 0.0 0.2 0.46 1 N-Methylpyrrolidone (NMP) 18.0 12.3 7.2 0.42 1 1,4-Dioxane 17.5 1.8 9.0 0.10 4 Ethanol 15.8 8.8 19.4 0.09 5 Diethyl carbonate 15.1 6.3 3.5 0.08 5 Methanol 14.7 12.3 22.3 0.07 5 acetone 15.5 10.4 7.0 0.06 5 dimethylformamide 17.4 13.7 11.3 0.05 5 Acetonitrile 15.3 18.0 6.1 0.03 5 Methyl Ethyl Ketone (MEK) 16.0 9.0 5.1 0.03 5

[0336] (Preparation of positive electrode active material)

[0337] The following positive electrode active materials were prepared.

[0338] NCM: NCM811 RL-08-D3 (Umicore)

[0339] Composition: LiNi 0.8 Co 0.1 Mn 0.1 O 2

[0340] (Calculation of HSP value of positive electrode active material: NCM)

[0341] The HSP value of NCM as the positive electrode active material was calculated in the same manner as that of Graphite 1.

[0342] Table 3 shows the evaluation results of the dispersibility used for calculating the HSP value of NCM.

[0343] [Table 3]

[0344] Type of solvent δD δP δH DISP evaluate Toluene 18.0 1.4 2.0 0.57 1 Hexane 14.9 0.0 0.0 0.50 1 Cyclohexane 16.8 0.0 0.2 0.45 1 1,4-Dioxane 17.5 1.8 9.0 0.26 2 Methanol 14.7 12.3 22.3 0.23 2 Ethanol 15.8 8.8 19.4 0.16 3 N-Methylpyrrolidone (NMP) 18.0 12.3 7.2 0.16 3 dimethylformamide 17.4 13.7 11.3 0.07 5 Diethyl carbonate 15.1 6.3 3.5 0.04 5 acetone 15.5 10.4 7.0 0.03 5 Acetonitrile 15.3 18.0 6.1 0.02 5 Methyl Ethyl Ketone (MEK) 16.0 9.0 5.1 0.00 5

[0345] Table 4 shows the solubility parameters of Graphite 1, Graphite 2, and NCM obtained based on the results shown in Tables 1, 2, and 3.

[0346] [Table 4]

[0347] Active substances δD δP δH Graphite 1 19.0 6.8 4.7 Graphite 2 20.0 5.8 2.6 NCM 16.5 0.4 0.9

[0348] (Examples 1 to 55, Comparative Examples 1 to 39, using graphite 1)

[0349] (Production of negative electrode with additives)

[0350] 2.0 parts by weight of AB (acetylene black: "DENKA BLACK Li100", manufactured by Denka Co., Ltd., average primary particle size: 35 nm) as a conductive aid, 3.0 parts by weight of CMC (carboxymethyl cellulose) as a binder resin, and 40.0 parts by weight of ion-exchanged water were stirred at 2000 rpm for 5 minutes using a planetary stirring type mixing and kneading device {Awato Ri Rentaro [manufactured by THINKY Co., Ltd.]}.

[0351] Next, 3.0 parts by weight of SBR (styrene butadiene rubber) as a binder resin was added, and the mixture was stirred at 2000 rpm for 5 minutes using a degassing machine. 91.0 parts by weight of graphite 1 as a negative electrode active material, 1.0 parts by weight of an additive, and 60.0 parts by weight of ion exchange water were added to the obtained dispersion, and the mixture was stirred at 2000 rpm for 5 minutes using a degassing machine to prepare a slurry for a negative electrode active material layer.

[0352] The obtained negative electrode active material layer slurry was applied to one side of the current collector (copper foil) using a coater with a gap set to 150 μm in the air, pre-dried overnight in a ventilation device, and then further dried at 100°C for 2 hours under reduced pressure (1.3 kPa) to obtain an electrode sheet. The electrode sheet was punched out near the center into 16 pieces. This operation was repeated several times, and three of the obtained electrodes were used as electrodes for a simple test of electrode brittleness (negative electrodes). The remaining electrodes were pressed twice for 3 seconds at 1.5 MPa using a press to make evaluation electrodes (negative electrodes). Each negative electrode was made for additives 1 to 21.

[0353] (Production of negative electrode without additives)

[0354] An electrode for a simple electrode brittleness test (negative electrode) and an electrode for evaluation (negative electrode) were prepared in the same manner as the negative electrode with the additive, except that Graphite 1 was used in an amount of 92.0 parts by weight and no additive was added.

[0355] <Calculation of electrode density>

[0356] The weight and thickness of the current collector and the evaluation electrode, which were pressed twice at 1.5 MPa for 3 seconds using a press, were measured, and the electrode density was calculated by the following formula.

[0357] Electrode density (g / cm 3) = (evaluation electrode weight (g) - collector weight (μg) × 10 -3 ) / (0.8 2 ×3.14×((evaluation electrode thickness (μm) - collector thickness (μm))×10 -4 ))

[0358] <Simple Test for Electrode Brittleness>

[0359] The electrode for the simple test of electrode brittleness was allowed to freely fall from a height of 30 cm onto a white paper. This operation was performed on three electrodes for the simple test of electrode brittleness, and the electrodes were evaluated according to the following criteria.

[0360] 0: The number of electrode sheets attached to white paper is 0

[0361] ×: The electrode sheet adhered to the white paper at least once

[0362] <Electrolyte penetration test>

[0363] Among the electrodes used for evaluation, the electrode density (g / cm 3 The difference between the maximum and minimum values ​​of 3 ) and record the arithmetic mean value as the electrode density (g / cm 3 ).

[0364] A stainless steel M3 flat washer (manufactured by ESCO) was placed in the center of each electrode, and 20 μL of electrolyte was put into the hole of the washer. The time until the droplets in the washer completely disappeared from the electrode surface was recorded in units of 1 second, and the arithmetic mean was taken as the electrolyte penetration time (penetration rate: minutes).

[0365] Electrolyte permeation tests were performed on electrolytes 1 to 4 respectively.

[0366] <Capacity retention rate after harsh test>

[0367] Fabrication of negative electrode half-cell for severe capacity retention test

[0368] Among the electrodes used for evaluation, the electrode density (g / cm 3 The difference between the maximum and minimum values ​​of 3 ) and record the arithmetic mean value as the electrode density (g / cm 3 ).

[0369] The negative electrode, separator [trade name "#3501", manufactured by Celgard], and lithium foil were stacked in order from the negative electrode side, and after injecting electrolyte, vacuum lamination was performed to prevent oxygen from entering therein, to produce a negative electrode half-cell for a severe capacity retention test.

[0370] Negative half-cell charge and discharge test

[0371] The capacity retention rate of the severe test negative electrode half-cell was evaluated by the following method at 25° C. using a charge and discharge measurement device “HJ-SD8” [manufactured by Hokuto Denko Co., Ltd.].

[0372] The battery was charged to 0V at a current of 0.05C using a constant current charging method (also called CC mode), and then discharged to 1.5V at a current of 0.05C after a 10-minute rest.

[0373] The capacity discharged at this time is referred to as [1 cycle discharge capacity (mAh)].

[0374] The charge and discharge were performed again under the same conditions, and the capacity discharged at this time was defined as [2 cycle discharge capacity (mAh)].

[0375] Next, the battery was charged to 0 V at a current of 0.1 C, and after a 10-minute rest, it was discharged to 1.5 V at a current of 0.1 C.

[0376] The capacity discharged at this time is referred to as [3-cycle discharge capacity (mAh)].

[0377] Furthermore, the battery was charged to 0 V at a current of 0.5 C, and after a 10-minute rest, it was discharged to 1.5 V at a current of 0.1 C.

[0378] The capacity discharged at this time is referred to as [4-cycle discharge capacity (mAh)].

[0379] Finally, the battery was charged to 0 V at a current of 1.0 C, and after a 10-minute rest, it was discharged to 1.5 V at a current of 0.1 C.

[0380] The capacity discharged at this time is referred to as [5-cycle discharge capacity (mAh)].

[0381] The capacity retention rate after the severe test was calculated for each of the three electrodes using the following formula, and the arithmetic mean thereof was taken as the capacity retention rate (%) after the severe test of the evaluation electrode.

[0382] Capacity retention rate after harsh test (%) = [5 cycle discharge capacity (mAh)] / [2 cycle discharge capacity (mAh)]

[0383] An electrolyte permeation test was performed on Examples 1 to 17 using Additives 1 to 17, Comparative Examples 1 to 4 using no additive, and Comparative Examples 5 to 8 using Additives 18 to 21.

[0384] The evaluation results using Graphite 1 are summarized in Tables 5 to 12.

[0385] Tables 5 and 6 are examples and comparative examples using electrolyte 1, Tables 7 and 8 are examples and comparative examples using electrolyte 2, Tables 9 and 10 are examples and comparative examples using electrolyte 3, and Tables 11 and 12 are examples and comparative examples using electrolyte 4.

[0386] It should be noted that the unit of HSP distance in the following tables is [MPa 0.5 ].

[0387]

[0388]

[0389]

[0390]

[0391]

[0392]

[0393]

[0394]

[0395] (Examples 56 to 106, Comparative Examples 40 to 82, using graphite 2)

[0396] Graphite 2 was used instead of Graphite 1 to produce negative electrodes with and without additives, and the calculation of electrode density, simple electrode brittleness test, and electrolyte permeation test were performed. The capacity retention rate test after the harsh test was not performed.

[0397] The evaluation results using Graphite 2 are summarized in Tables 13 to 20.

[0398] Tables 13 and 14 are examples and comparative examples using electrolyte 1, Tables 15 and 16 are examples and comparative examples using electrolyte 2, Tables 17 and 18 are examples and comparative examples using electrolyte 3, and Tables 19 and 20 are examples and comparative examples using electrolyte 4.

[0399]

[0400]

[0401]

[0402]

[0403]

[0404]

[0405]

[0406]

[0407] (Examples 107 to 149, Comparative Examples 83 to 133, using NCM)

[0408] (Production of positive electrode with additives)

[0409] 1.0 parts by weight of the additive and 100.0 parts by weight of N-methyl-2-pyrrolidone (NMP) were stirred at 2000 rpm for 5 minutes using a planetary stirring type mixing and kneading device {Degassing Rentaro [manufactured by THINKY Co., Ltd.]}. Next, 3.0 parts by weight of polyvinylidene fluoride (manufactured by Kishida Chemical) as a binder resin was added and stirred at 2000 rpm for 5 minutes using the Degassing Rentaro.

[0410] After adding 89.0 parts by weight of NCM as a positive electrode active material and 7.0 parts by weight of AB {acetylene black: "DENKA BLACK Li100", manufactured by Denka Corporation} as a conductive aid, the mixture was stirred at 2000 rpm for 4 minutes using a degassing machine to prepare a slurry for a positive electrode active material layer.

[0411] The obtained positive electrode active material layer slurry was applied to one side of a current collector (aluminum foil, manufactured by Hohsen Co., Ltd.) using a coater with a gap set to 150 μm in the air, pre-dried overnight in a ventilator, and then further dried at 100°C for 2 hours under reduced pressure (1.3 kPa) to obtain an electrode sheet. The electrode sheet was punched out near the center into 16 pieces. This operation was repeated several times, and three of the obtained electrodes were used as electrodes for a simple test of electrode brittleness (positive electrodes). The remaining electrodes were pressed twice for 3 seconds at 4.0 MPa using a press to make evaluation electrodes (positive electrodes). Each positive electrode was made for additives 1 to 21.

[0412] (Production of positive electrode without additives)

[0413] An electrode for a simple electrode brittleness test (positive electrode) and an electrode for evaluation (positive electrode) were prepared in the same manner as the positive electrode with the additive, except that the amount of NCM was 90.0 parts by weight and no additive was added.

[0414] For the electrode for simple electrode brittleness test (positive electrode) and evaluation electrode (positive electrode), the electrode density calculation, simple electrode brittleness test, and electrolyte permeation test were performed in the same steps as the negative electrode. The capacity retention rate test after the harsh test was not performed.

[0415] It should be noted that when calculating the electrode density, the calculation formula is corrected according to the different punching diameters of the electrode sheets.

[0416] The evaluation results using NCM are summarized in Tables 21 to 28.

[0417] Tables 21 and 22 are examples and comparative examples using electrolyte 1, Tables 23 and 24 are examples and comparative examples using electrolyte 2, Tables 25 and 26 are examples and comparative examples using electrolyte 3, and Tables 27 and 28 are examples and comparative examples using electrolyte 4.

[0418]

[0419]

[0420]

[0421]

[0422]

[0423]

[0424] [Table 27]

[0425] Embodiment 149 Types of additives Additive 8 Types of electrode active materials NCM HSP distance between active substances and additives 11.9 Type of electrolyte Electrolyte 4 HSP distance between electrolyte and additive 13.5 Electrode brittleness 〇 <![CDATA[Electrode density, g / cm 3 > 3.04 Penetration rate, min 129

[0426]

[0427] According to these results, in electrodes using the same active material and electrolyte, the permeation rate in each example where the HSP distance between the active material and the additive and the HSP distance between the electrolyte and the additive were within the specified ranges was faster than that in the comparative example (permeation time was shorter).

[0428] In addition, regarding the electrode density, the electrode density was varied within a relatively wide range in the comparative examples (for example, the electrode density was varied within the range of 1.53 to 1.64 in comparative examples 1 to 4), and the permeation rate in each embodiment was faster than that in any of the comparative examples. This indicates that, regardless of the electrode density, the permeability of the electrolyte can be excellent by satisfying the conditions of the present invention.

[0429] In Examples 1 to 17, the battery performance (harsh test) was confirmed for the additives 1 to 17 effective for permeability, and none of them had an adverse effect on the battery performance.

[0430] In addition, the HSP distance between the active material and the additive is less than 4.0MPa 0.5 In the examples (Examples 11, 12, etc.), the compatibility between the additive and the active material is high, so the surface of the active material is corroded by the additive, and the electrode brittleness is evaluated as ×.

Claims

1. An electrode composition, which is an electrode composition for a secondary battery electrode layer containing an electrolyte, wherein: The electrode composition satisfies all of the following conditions (1) to (4): (1) Contains active substances and additives but does not contain binder resin; (2) The HSP distance Ra_Act between the additive and the active material is 12.0 MPa 0.5 the following; (3) The HSP distance Ra_Elec between the additive and the electrolyte is 14.0 MPa 0.5 the following; (4) The weight average molecular weight Mw of the additive is 50,000 or less.

2. An electrode composition, which is an electrode composition for a secondary battery electrode layer containing an electrolyte, wherein: The electrode composition satisfies all of the following conditions (1) to (3): (1) Containing active substances, binder resins and additives; (2) The HSP distance Ra_Act between the additive and the active material is 12.0 MPa 0.5 the following; (3) The HSP distance Ra_Elec between the additive and the electrolyte is 14.0 MPa 0.5 the following.

3. The electrode composition according to claim 1 or 2, wherein The HSP distance Ra_Act between the additive and the active material is 4.0 MPa 0.5 above.

4. The electrode composition according to claim 1 or 2, wherein The HSP distance Ra_Elec between the additive and the electrolyte is 12.0 MPa 0.5 the following.

5. The electrode composition according to claim 1 or 2, wherein The additive is an alkylene oxide adduct of an alkyl alcohol or an alkylene oxide adduct of an alkylene glycol.

6. The electrode composition according to claim 5, wherein The alkyl alcohol is a saturated alkyl alcohol.

7. The electrode composition according to claim 1 or 2, wherein The active material is at least one selected from the group consisting of a composite oxide containing at least one transition metal element, artificial graphite, and natural graphite.

8. The electrode composition according to claim 1 or 2, wherein The solvent of the electrolyte is a mixed solvent of ethylene carbonate and diethyl carbonate; a mixed solvent of ethylene carbonate, ethyl methyl carbonate and diethyl carbonate; or a mixed solvent of ethylene carbonate and propylene carbonate. 9 . An electrode for a secondary battery, which is obtained by compression molding the electrode composition according to claim 1 or 2. 10 . A secondary battery comprising the secondary battery electrode according to claim 9 .

11. A secondary battery comprising a current collector layer, a secondary battery electrode layer and a separator layer, wherein: The secondary battery satisfies all of the following conditions (1) to (4): (1) The secondary battery electrode layer contains active materials, electrolyte and additives, but does not contain a binder resin; (2) The HSP distance Ra_Act between the additive and the active material is 12.0 MPa 0.5 the following; (3) The HSP distance Ra_Elec between the additive and the electrolyte is 14.0 MPa 0.5 the following; (4) The weight average molecular weight Mw of the additive is 50,000 or less.

12. A secondary battery comprising a current collector layer, a secondary battery electrode layer and a separator layer, wherein: The secondary battery satisfies all of the following conditions (1) to (3): (1) The secondary battery electrode layer contains active material, electrolyte, binder resin and additives; (2) The HSP distance Ra_Act between the additive and the active material is 12.0 MPa 0.5 the following; (3) The HSP distance Ra_Elec between the additive and the electrolyte is 14.0 MPa 0.5 the following.

13. An electrolyte penetration method, which is a method for allowing an electrolyte to penetrate into an electrode composition, wherein: The electrolyte infiltration method satisfies all of the following conditions (1) to (4): (1) The electrode composition contains active materials and additives but does not contain a binder resin; (2) The HSP distance Ra_Act between the additive and the active material is 12.0 MPa 0.5 the following; (3) The HSP distance Ra_Elec between the additive and the electrolyte is 14.0 MPa 0.5 the following; (4) The weight average molecular weight Mw of the additive is 50,000 or less.

14. An electrolyte penetration method, which is a method for allowing an electrolyte to penetrate into an electrode composition, wherein: The electrolyte infiltration method satisfies all of the following conditions (1) to (3): (1) The electrode composition contains an active material, a binder resin and an additive; (2) The HSP distance Ra_Act between the additive and the active material is 12.0 MPa 0.5 the following; (3) The HSP distance Ra_Elec between the additive and the electrolyte is 14.0 MPa 0.5 the following.

15. A method for manufacturing a secondary battery, comprising the steps of: allowing an electrolyte to penetrate into a battery cell comprising a current collector layer, an electrode composition layer, and a separator layer, to obtain a secondary battery electrode layer containing the electrolyte in the electrode composition layer, wherein: The method for manufacturing a secondary battery satisfies all of the following conditions (1) to (4): (1) The electrode composition layer contains active materials and additives but does not contain a binder resin; (2) The HSP distance Ra_Act between the additive and the active material is 12.0 MPa 0.5 the following; (3) The HSP distance Ra_Elec between the additive and the electrolyte is 14.0 MPa 0.5 the following; (4) The weight average molecular weight Mw of the additive is 50,000 or less.

16. A method for manufacturing a secondary battery, comprising the steps of: allowing an electrolyte to penetrate into a battery cell comprising a current collector layer, an electrode composition layer, and a separator layer, to obtain a secondary battery electrode layer containing the electrolyte in the electrode composition layer, wherein: The method for manufacturing a secondary battery satisfies all of the following conditions (1) to (3): (1) The electrode composition layer contains an active material, a binder resin and an additive; (2) The HSP distance Ra_Act between the additive and the active material is 12.0 MPa 0.5 the following; (3) The HSP distance Ra_Elec between the additive and the electrolyte is 14.0 MPa 0.5 the following.

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