Battery member, secondary battery, and method for manufacturing battery member

Abstract

A battery member according to an aspect of the present invention is provided with: a pair of base materials; a pair of electrolyte layers which are provided between the base materials and the edges of which are joined together; and an electrode disposed between the electrolyte layers, wherein the electrode has a collector and an electrode mixture layer disposed on at least one surface of the collector, and the electrode mixture layer contains an electrode active material, an organic solvent, and an electrolyte salt.

Description

Technical Field

[0001] The present invention relates to a battery member, a secondary battery, and a method for manufacturing a battery member.

Background Art

[0002] In recent years, the popularity of electric vehicles and hybrid vehicles with low environmental impact has been increasing. These vehicles are equipped with secondary batteries such as nickel-metal hydride batteries and lithium-ion secondary batteries. For secondary batteries for vehicles, not only battery characteristics but also high safety is required. As a method for improving the safety of secondary batteries, a method of changing the electrolytic solution to a solid electrolyte is known (for example, Patent Document 1).

[0003] Further, as a means for improving the battery characteristics of a secondary battery using a solid electrolyte layer, a method of impregnating a positive electrode and a negative electrode with an electrolytic solution or a gel electrolyte is known (for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] For example, the secondary battery described in Patent Document 2 is obtained by sequentially laminating a positive electrode, a sheet of solid electrolyte, and a negative electrode to form a single cell, and housing an assembly of these single cells in a battery container. The positive electrode and the negative electrode are impregnated with an organic electrolytic solution or a gel electrolyte. However, according to the studies by the present inventors, in an electrode impregnated with an organic electrolytic solution or a gel electrolyte, since the solvent contained in the electrolytic solution is likely to volatilize during manufacturing or over time, there is a problem in suitably manufacturing a secondary battery having desired characteristics.

[0006] One aspect of the present invention aims to suppress the volatilization of an organic solvent in an electrode mixture layer in an electrode in which an electrolyte solution containing an electrolyte salt and an organic solvent is included in the electrode mixture layer. **Means for Solving the Problems**

[0007] One aspect of the present invention provides a battery member including a pair of base materials, a pair of electrolyte layers provided between the pair of base materials and having their edges adhered to each other, and an electrode disposed between the pair of electrolyte layers. The electrode has a current collector and an electrode mixture layer provided on at least one surface of the current collector, and the electrode mixture layer contains an electrode active material, an organic solvent, and an electrolyte salt.

[0008] In this battery member, since the electrode is covered with the pair of base materials and the pair of electrolyte layers, volatilization of the organic solvent from the electrode mixture layer is suppressed. In particular, in this battery member, since the edges of the pair of electrolyte layers are adhered to each other, volatilization of the organic solvent from the adhered portion can be suppressed.

[0009] Also, if an organic solvent volatilizes during the manufacture of the battery member and a deviation from the charged composition occurs, it is difficult to design a secondary battery to obtain desired battery characteristics. In this battery member, since volatilization from the electrode mixture layer is suppressed, the deviation from the charged composition is reduced, making it easier to manufacture a secondary battery having desired battery characteristics.

[0010] Also, in some cases, it is necessary to additionally inject an electrolyte solution into the electrode mixture layer during the production of the secondary battery. However, in this battery member, since volatilization of the organic solvent from the electrode mixture layer can be suppressed, the step of additionally injecting the electrolyte solution during the production of the secondary battery can be omitted, and the manufacturing time of the secondary battery can also be shortened.

[0011] Furthermore, in this battery member, the volatilization of the organic solvent can be suppressed over a long period by the base material and the electrolyte layer. Therefore, it is possible to store the battery member for a long time before manufacturing the secondary battery.

[0012] In the battery member, the electrolyte layer may contain a polymer, oxide particles, and an electrolyte salt.

[0013] In the battery member, the organic solvent may contain a carbonate ester.

[0014] In the battery member, the electrode binder layer may further contain a polymer capable of gelling the organic solvent. Thereby, the adhesion between the current collector and the electrode binder layer is improved, the base material can be easily peeled off from the battery member, and the manufacture of the secondary battery becomes easy.

[0015] The pair of base materials may cover the entire pair of electrolyte layers. Thereby, the volatilization of the organic solvent from the electrode binder layer can be further suppressed.

[0016] Another aspect of the present invention provides a secondary battery including a pair of electrolyte layers with their edges adhered to each other and an electrode provided between the pair of electrolyte layers. The electrode has a current collector and an electrode binder layer provided on at least one surface of the current collector, and the electrode binder layer contains an electrode active material, an organic solvent, and an electrolyte salt.

[0017] In this secondary battery, since the organic solvent is easily retained in the electrode binder layer, the interfaces between the electrode active material and the electrolyte salt which is an ion conduction component, and between the electrode binder layer and the electrolyte layer are respectively well formed by the organic solvent, and the battery performance of the secondary battery such as cycle characteristics can be improved.

[0018] In the secondary battery, the electrolyte layer may contain a polymer, oxide particles, and an electrolyte salt. In the secondary battery, the organic solvent may contain a carbonate ester. In the secondary battery, the electrode binder layer may further contain a polymer capable of gelling the organic solvent.

[0019] Another aspect of the present invention provides a method for manufacturing a battery member, comprising: step (a) of obtaining a laminate including a pair of base materials, a pair of electrolyte layers provided between the pair of base materials, and an electrode disposed between the pair of electrolyte layers; and step (b) of bonding the edges of the pair of electrolyte layers to each other, wherein the electrode has a current collector and an electrode mixture layer provided on at least one surface of the current collector, and the electrode mixture layer contains an electrode active material, an organic solvent, and an electrolyte salt.

[0020] Step (a) may include, in this order: step (w1) of forming an electrode mixture layer by adding a composition containing an organic solvent and an electrolyte salt into an electrode active material layer containing an electrode active material provided on at least one surface of the current collector to obtain an electrode; and step (w2) of disposing the electrode between the pair of electrolyte layers.

[0021] Step (a) may include, in this order: step (x1) of disposing an electrode laminate including a current collector and an electrode active material layer provided on at least one surface of the current collector and containing an electrode active material between the pair of electrolyte layers; and step (x2) of forming an electrode mixture layer by adding a composition containing an organic solvent and an electrolyte salt into the electrode active material layer to obtain an electrode.

[0022] Step (a) may include, in this order: step (y1) of disposing an electrode laminate including a current collector and an electrode active material layer provided on at least one surface of the current collector and containing an electrode active material on a first electrolyte layer of a first electrolyte sheet having a first base material and a first electrolyte layer provided on one surface of the first base material; step (y2) of forming an electrode mixture layer by adding a composition containing an organic solvent and an electrolyte salt into the electrode active material layer to obtain an electrode; and step (y3) of laminating a second electrolyte sheet having a second base material and a second electrolyte layer provided on one surface of the second base material such that the second electrolyte layer faces the electrode mixture layer side.

[0023] The electrode mixture layer may further contain a polymer capable of gelling the organic solvent. In this case, step (c) of heating the composition may be further provided after step (b).

[0024] The composition may further contain a polymerizable compound, and the polymerizable compound may be a compound that becomes a polymer capable of gelling an organic solvent by polymerization. In this case, after step (b), a step (d) of polymerizing the polymerizable compound in the electrode mixture layer may be further provided.

[0025] Conventionally, when gelling the organic solvent in the electrode mixture layer, it is common to volatilize the organic solvent. In one aspect of the present invention, the organic solvent is gelled with a gellable polymer or polymerizable compound. Thereby, since the organic solvent can be gelled without requiring a step of volatilizing the organic solvent, a secondary battery having desired characteristics can be more suitably obtained than in the prior art.

[0026] In addition, by previously adding an organic solvent and a polymer or polymerizable compound to the electrode mixture layer and then gelling the organic solvent, a composition containing an electrolytic solution can be easily permeated even into a high-density electrode mixture layer. Therefore, in the battery member manufactured by this method, liquid leakage of the organic solvent from the electrode mixture layer can also be suppressed.

[0027] Furthermore, when the above composition contains a gellable polymer or polymerizable compound, the adhesion between the current collector and the electrode mixture layer is improved by gelling the organic solvent, and a battery member that can easily peel the base material from the battery member can be obtained. By using such a battery member, the manufacture of the secondary battery also becomes easy.

[0028] In this manufacturing method, the electrolyte layer may contain a polymer, oxide particles, and an electrolyte salt. The organic solvent may contain a carbonic acid ester. The pair of base materials may cover the entire pair of electrolyte layers.

Advantages of the Invention

[0029] According to one aspect of the present invention, in an electrode in which an electrolytic solution containing an electrolyte salt and an organic solvent is included in an electrode mixture layer, volatilization of the organic solvent from the electrode mixture layer can be suppressed.

Brief Description of the Drawings

[0030]

Figure 1

Figure 2

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Figure 9

DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, embodiments of the present invention will be described with appropriate reference to the drawings. However, the present invention is not limited to the following embodiments. In the following embodiments, the constituent elements (including steps, etc.) are not essential unless otherwise specified. The sizes of the constituent elements in each figure are conceptual, and the relative size relationships between the constituent elements are not limited to those shown in each figure.

[0032] The numerical values and ranges thereof in this specification do not limit the present invention. The numerical range indicated by "~" in this specification indicates a range including the numerical values described before and after "~" as the minimum value and the maximum value, respectively. In the numerical ranges described stepwise in this specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of other stepwise descriptions. Also, in the numerical ranges described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.

[0033] In this specification, "positive electrode" and "negative electrode" may be collectively referred to as "electrode", and the same applies to similar expressions such as "electrode active material" and "electrode binder layer".

[0034] FIG. 1 is a perspective view showing a secondary battery according to an embodiment. As shown in FIG. 1, the secondary battery 1 includes an electrode group 2 composed of a positive electrode group including a positive electrode and a negative electrode group including a negative electrode, and a bag-shaped battery exterior 3 that houses the electrode group 2.

[0035] The battery exterior 3 may be formed of, for example, a laminate film. The laminate film may be a laminated film in which a resin film such as a polyethylene terephthalate (PET) film, a metal foil such as aluminum, copper, or stainless steel, and a sealant layer such as polypropylene are laminated in this order.

[0036] FIG. 2 is an exploded perspective view showing an embodiment of the electrode group 2 of the secondary battery 1 shown in FIG. 1. As shown in FIG. 2, the electrode group 2A is formed by laminating a positive electrode group 6 and a negative electrode group 7. The positive electrode group 6 and the negative electrode group 7 are each provided with a positive electrode current collector tab 4 and a negative electrode current collector tab 5. The positive electrode current collector tab 4 and the negative electrode current collector tab 5 protrude from the inside to the outside of the battery exterior 3 shown in FIG. 1 so that the positive electrode included in the positive electrode group 6 and the negative electrode included in the negative electrode group 7 can be electrically connected to the outside of the secondary battery 1.

[0037] Fig. 3(a) is a schematic cross-sectional view taken along line IIIa-IIIa in Fig. 2. That is, Fig. 3(a) is a schematic cross-sectional view of the positive electrode group 6. As shown in Fig. 3(a), the positive electrode group 6 includes a pair of electrolyte layers 8, 8 and a positive electrode 9 disposed between the pair of electrolyte layers 8, 8. The edges 8e, 8e of the pair of electrolyte layers 8, 8 are adhered to each other.

[0038] The positive electrode 9 includes a positive electrode current collector 10 and a positive electrode mixture layer 11 provided on one surface 10a of the positive electrode current collector 10. The positive electrode current collecting tab 4 shown in Fig. 2 is provided so as to be connected to the positive electrode current collector 10.

[0039] The positive electrode current collector 10 may be formed of a metal such as aluminum, titanium, tantalum, or an alloy thereof. Since the positive electrode current collector 10 is lightweight and has a high weight energy density, it is preferably formed of aluminum or an alloy thereof.

[0040] In one embodiment, the positive electrode mixture layer 11 contains a positive electrode active material, an organic solvent, and an electrolyte salt (also referred to as "electrolyte salt A").

[0041] The positive electrode active material may be a lithium transition metal compound such as a lithium transition metal oxide or a lithium transition metal phosphate.

[0042] The lithium transition metal oxide may be, for example, lithium manganate, lithium nickelate, lithium cobaltate, etc. The lithium transition metal oxide may be a lithium transition metal oxide in which a part of transition metals such as Mn, Ni, Co contained in lithium manganate, lithium nickelate, lithium cobaltate, etc. is substituted with one or more other transition metals or metal elements (typical elements) such as Mg, Al. That is, the lithium transition metal oxide is LiM 1 O 2 Or LiM 1 2 O 4 (M 1 includes at least one transition metal) and may be a compound represented by. Specifically, the lithium transition metal oxide is Li(Co 1 / 5 Ni3 / 5 Mn 1 / 5 )O 2、 Li(Co 1 / 3 Ni 1 / 3 Mn 1 / 3 )O 2 、LiNi 1 / 2 Mn 1 / 2 O 2 、LiNi 1 / 2 Mn 3 / 2 O 4 and the like may be used.

[0043] From the viewpoint of further improving the energy density, the lithium transition metal oxide is preferably a compound represented by the following formula (1). Li a Ni b Co c M 2 d O 2+e (1) [In formula (1), M 2 is at least one selected from the group consisting of Al, Mn, Mg, and Ca, and a, b, c, d, and e are numbers satisfying 0.2 ≦ a ≦ 1.2, 0.5 ≦ b ≦ 0.9, 0.1 ≦ c ≦ 0.4, 0 ≦ d ≦ 0.2, -0.2 ≦ e ≦ 0.2, and b + c + d = 1, respectively.]

[0044] The lithium transition metal phosphate may be LiFePO 4 , LiMnPO 4 , LiMn x M 3 1-x PO 4 (0.3 ≦ x ≦ 1, M 3 is at least one element selected from the group consisting of Fe, Ni, Co, Ti, Cu, Zn, Mg, and Zr), etc.

[0045] The content of the positive electrode active material may be 70% by mass or more, 80% by mass or more, or 90% by mass or more based on the total amount of the positive electrode binder layer. The content of the positive electrode active material may be 99% by mass or less based on the total amount of the positive electrode binder layer.

[0046] The organic solvent is a solvent capable of dissolving electrolyte salt A. When the positive electrode active material layer further contains polymer A (details will be described later), the organic solvent is preferably a solvent capable of dissolving polymer A, for example, a solvent capable of dissolving polymer A at at least 100 °C. Note that ionic liquids are not included in the organic solvents described in this specification.

[0047] The organic solvent may include, for example, at least one selected from the group consisting of esters, ethers, amides, sulfoxides, and sulfones, and preferably contains an ester. The organic solvent is used alone or in combination of two or more.

[0048] Examples of the ester include carbonate esters, fatty acid esters, lactones, phosphate esters, etc. The organic solvent preferably contains a carbonate ester.

[0049] Examples of the carbonate ester include ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, chloroethylene carbonate, chloropropylene carbonate, etc.

[0050] Examples of the fatty acid ester include methyl propionate, ethyl propionate, etc. Examples of the lactone include γ-butyrolactone, etc. Examples of the phosphate ester include triester phosphate, etc.

[0051] The ether may be linear or cyclic. Examples of the linear ether include diethyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, trimethoxymethane, etc. Examples of the cyclic ether include tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, etc.

[0052] Examples of amides include formamide and dimethylformamide. Examples of sulfoxides include dimethyl sulfoxide. Examples of sulfones include sulfolane.

[0053] The content (total content) of the organic solvent may be 1% by mass or more, 3% by mass or more, or 5% by mass or more, and may be 30% by mass or less, 20% by mass or less, or 10% by mass or less, based on the total amount of the positive electrode mixture layer.

[0054] The electrolyte salt A may be at least one selected from the group consisting of lithium salts, sodium salts, calcium salts, and magnesium salts.

[0055] The anion of the electrolyte salt A is a halide ion (I - , Cl - , Br - , etc.), SCN - , BF 4 - , BF 3 (CF 3 ) - , BF 3 (C 2 F 5 ) - , PF 6 - , ClO 4 - , SbF 6 - , N(SO 2 F) 2 - , N(SO 2 CF 3 ) 2 - , N(SO 2 C 2 F 5 ) 2 - , BPh 4 - , B(C 2 H 4 O 2 ) 2 - , C(FSO 2 ) 3 - , C(CF3 SO 2 ) 3 - 、CF 3 COO - 、CF 3 SO 2 O - 、C 6 F 5 SO 2 O - 、[B(C 2 O 4 ) 2 - and the like. The anion is preferably PF 6 - 、BF 4 - 、N(SO 2 F) 2 - 、N(SO 2 CF 3 ) 2 - 、[B(C 2 O 4 ) 2 - 、or ClO 4 - .

[0056] Note that the following abbreviations may be used below. [FSI] - :N(SO 2 F) 2 - 、bis(fluorosulfonyl)imide anion [TFSI] - :N(SO 2 CF 3 ) 2 - 、bis(trifluoromethanesulfonyl)imide anion [BOB] - :[B(C 2 O 4 ) 2 - 、bisoxalate borate anion [f3C] - :C(FSO 2 ) 3 - ​​​, tris(fluorosulfonyl)carbanion

[0057] The lithium salt is LiPF 6 、LiBF 4 、Li[FSI], Li[TFSI], Li[f3C], Li[BOB], LiClO 4 、LiCF 3 BF 3 、LiC 2 F 5 BF 3 、LiC 3 F 7 BF 3 、LiC 4 F 9 BF 3 、Li[C(SO 2 CF 3 ) 3 、LiCF 3 SO 3 、LiCF 3 COO, and LiRCOO (R is an alkyl group having 1 to 4 carbon atoms, a phenyl group, or a naphthyl group.) may be at least one selected from the group consisting of.

[0058] The sodium salt is NaPF 6 、NaBF 4 、Na[FSI], Na[TFSI], Na[f3C], Na[BOB], NaClO 4 、NaCF 3 BF 3 、NaC 2 F 5 BF 3 、NaC 3 F 7 BF 3 、NaC 4 F 9 BF 3 、Na[C(SO 2 CF 3 ) 3 、NaCF 3 SO 3 、NaCF 3 COO, and NaRCOO (R is an alkyl group having 1 to 4 carbon atoms, a phenyl group, or a naphthyl group.) may be at least one selected from the group consisting of.

[0059] The calcium salts may be at least one selected from the group consisting of Ca(PF 6 ) 2 , Ca(BF 4 ) 2 , Ca[FSI] 2 , Ca[TFSI] 2 , Ca[f3C] 2 , Ca[BOB] 2 , Ca(ClO 4 ) 2 , Ca(CF 3 BF 3 ) 2 , Ca(C 2 F 5 BF 3 ) 2 , Ca(C 3 F 7 BF 3 ) 2 , Ca(C 4 F 9 BF 3 ) 2 , Ca[C(SO 2 CF 3 ) 3 2 , Ca(CF 3 SO 3 ) 2 , Ca(CF 3 COO) 2 , and Ca(RCOO) 2 (wherein R is an alkyl group having 1 to 4 carbon atoms, a phenyl group, or a naphthyl group).

[0060] The magnesium salts are Mg(PF 6 ) 2 , Mg(BF 4 ) 2 , Mg[FSI] 2 , Mg[TFSI] 2 , Mg[f3C] 2 , Mg[BOB] 2 , Mg(ClO 4 ) 2 , Mg(CF 3 BF 3 ) 2 , Mg(C 2 F 5 BF​3 ) 2 , Mg(C 3 F 7 BF 3 ) 2 , Mg(C 4 F 9 BF 3 ) 2 , Mg[C(SO 2 CF 3 ) 3 2 , Mg(CF 3 SO 3 ) 2 , Mg(CF 3 COO) 2 , and Mg(RCOO) 2 (R is an alkyl group having 1 to 4 carbon atoms, a phenyl group, or a naphthyl group.) may be at least one selected from the group consisting of.

[0061] Among these, from the viewpoints of dissociability and electrochemical stability, electrolyte salt A is preferably LiPF 6 , LiBF 4 , Li[FSI], Li[TFSI], Li[f3C], Li[BOB], LiClO 4 , LiCF 3 BF 3 , LiC 2 F 5 BF 3 , LiC 3 F 7 BF 3 , LiC 4 F 9 BF 3 , Li[C(SO 2 CF 3 ) 3 3 SO 3 , LiCF 3 , LiCF 6 COO, and LiRCOO (R is an alkyl group having 1 to 4 carbon atoms, a phenyl group, or a naphthyl group.) may be at least one selected from the group consisting of, more preferably Li[TFSI], Li[FSI], LiPF 4 , LiBF 4 ​​At least one selected from the group consisting of, and more preferably Li[TFSI] or Li[FSI].

[0062] The content of electrolyte salt A may be 0.1% by mass or more, 0.4% by mass or more, or 0.7% by mass or more, and may be 4.8% by mass or less, 3.2% by mass or less, or 1.6% by mass or less, based on the total amount of the positive electrode mixture layer.

[0063] The concentration of electrolyte salt A per unit volume of the organic solvent may be 0.3 mol / L or more, 0.6 mol / L or more, or 1.0 mol / L or more, and may be 2.0 mol / L or less, 1.7 mol / L or less, or 1.5 mol / L or less.

[0064] The positive electrode mixture layer 11 may contain a polymer capable of gelling the organic solvent (also referred to as "polymer A") from the viewpoints of suppressing leakage of the organic solvent from the secondary battery 1 and improving the adhesion between the positive electrode current collector 10 and the positive electrode mixture layer 11.

[0065] In this specification, a polymer capable of gelling an organic solvent means a polymer that can greatly reduce the fluidity of the organic solvent. Specifically, it means a polymer in which the distance between position A and position B is less than 1 cm in the following fluidity evaluation.

[0066] First, 5 g of a mixture of an organic solvent and a polymer (Polymer A) capable of gelling the organic solvent (organic solvent / Polymer A = 90 / 10 (mass ratio)) is placed in a glass vial (manufactured by AS ONE Corporation, Labolance screw tube vial No. 4, 13.5 mL, cylindrical shape with a bottom diameter of about 2 cm and a height of about 4 cm), and the vial is capped. Subsequently, after melting Polymer A at a temperature above its glass transition temperature, the vial is allowed to stand at 25°C for 20 hours with the bottom side of the glass vial facing down and the cap side facing up. The position of the uppermost surface (the surface farthest from the bottom of the glass vial) of the mixture of the organic solvent and Polymer A in the glass vial after this standing is designated as Position A. Then, the vial is allowed to stand at 25°C for 10 minutes with the top and bottom of the glass vial reversed (the bottom side of the glass vial facing up and the cap side facing down). The position of the lowermost surface (the surface farthest from the bottom of the glass vial) of the mixture of the organic solvent and Polymer A in the glass vial after this standing is designated as Position B. Based on the distance between Position A and Position B thus obtained, the fluidity is evaluated.

[0067] Polymer A may be a polymer that gels by being dissolved in an organic solvent by heating and then cooled, a polymer having a functional group that undergoes ring-opening and cross-linking to gel by a cation or anion contained in an electrolyte salt, etc. Polymer A may also be a polymer obtained by adding a polymerizable compound (monomer) described later together with a polymerization initiator to an organic solvent and polymerizing the monomer by heating or the like, resulting in Polymer A.

[0068] Polymer A may contain, for example, monomer units derived from (meth)acrylic compounds. Examples of (meth)acrylic compounds include methyl methacrylate, methyl acrylate, N-isopropylacrylamide, pentaerythritol tetraacrylate, 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl acrylate, 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl methacrylate, (ethylene glycol) methacrylate, trimethylolpropane triacrylate, methyl (3-ethyloxetan-3-yl) methacrylate, and the like.

[0069] Polymer A may contain monomer units derived from, for example, vinylidene fluoride, hexafluoropropylene, acrylonitrile, styrene, diallyldimethylammonium-bis(trifluoromethanesulfonyl)imide, isoprene monoxide, or ethylene glycol diglycidyl ether.

[0070] Polymer A may be a homopolymer containing only one of the above monomer units, a copolymer containing two or more of the above monomer units, or a copolymer containing one or more of the above monomer units and one or more monomer units other than the above monomer units.

[0071] Examples of homopolymers include poly(3-ethyloxetan-3-yl)methyl methacrylate, polymethyl acrylate, polymethyl methacrylate, poly(N-isopropylacrylamide), poly(2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl acrylate), poly(2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl methacrylate), polyacrylamide, polyglycidyl methacrylate, polyvinylidene fluoride, polyacrylonitrile, poly(diallyldimethylammonium-bis(trifluoromethanesulfonyl)imide), polyethylene glycol, etc. Examples of copolymers include copolymers of vinylidene fluoride and hexafluoropropylene, copolymers of methyl methacrylate and oxetanyl methacrylate, etc.

[0072] Polymer A is used alone or in combination of two or more of the above polymers. From the viewpoint of extending the life and increasing the input / output of the secondary battery 1, Polymer A is preferably at least one selected from the group consisting of a polymer containing pentaerythritol tetraacrylate as a monomer unit, polyvinylidene fluoride, a copolymer of vinylidene fluoride and hexafluoropropylene, and a copolymer of methyl methacrylate and oxetanyl methacrylate.

[0073] The content of Polymer A may be 0.01% by mass or more, 0.1% by mass or more, or 1% by mass or more, and may be 20% by mass or less, 10% by mass or less, or 5% by mass or less, based on the total amount of the positive electrode active material layer.

[0074] The content of Polymer A may be 0.5 part by mass or more, 2 parts by mass or more, or 4 parts by mass or more, and may be 20 parts by mass or less, 15 parts by mass or less, or 10 parts by mass or less, with respect to 100 parts by mass of the total content of the organic solvent, electrolyte salt, and Polymer A.

[0075] The positive electrode active material layer 11 may further contain an ionic liquid. The ionic liquid contains the following anion component and cation component. Note that the ionic liquid in this specification is a substance that is liquid at -20°C or higher.

[0076] The anion component of the ionic liquid is not particularly limited, but is Cl - , Br - , I - and other halogen anions, BF 4 - [FSI] - and other inorganic anions, B(C 6 H 5 ) 4 - , CH 3 SO 3 - , CF 3 SO 3 - , N(C 4 F 9 SO 2 ) 2 - , [TFSI] - , N(SO 2 CF 2 CF 3 ) 2 - and other organic anions, etc. The anion component of the ionic liquid is preferably B(C 6 H 5 ) 4 - , CH 3 SO 3 - , N(C4 F 9 SO 2 ) 2 - 、CF 3 SO 3 - 、[FSI] - 、[TFSI] - and N(SO 2 CF 2 CF 3 ) 2 - contains at least one selected from the group consisting of, and from the viewpoint of further improving the ionic conductivity with a relatively low viscosity and further improving the charge and discharge characteristics, more preferably, N(C 4 F 9 SO 2 ) 2 - 、CF 3 SO 3 - 、[FSI] - 、[TFSI] - 、and N(SO 2 CF 2 CF 3 ) 2 - contains at least one selected from the group consisting of, and more preferably contains [FSI] - .

[0077] The cation component of the ionic liquid is not particularly limited, but is preferably at least one selected from the group consisting of a chain quaternary onium cation, a piperidinium cation, a pyrrolidinium cation, a pyridinium cation, and an imidazolium cation.

[0078] The chain quaternary onium cation is, for example, a compound represented by the following general formula (2). [Chemical formula] In formula (2), R 1 ~R 4 are each independently a chain alkyl group having 1 to 20 carbon atoms, or R-O-(CH 2 ) nrepresents a chain-like alkoxyalkyl group represented by - (where R represents a methyl group or an ethyl group, and n represents an integer from 1 to 4), and X represents a nitrogen atom or a phosphorus atom. R 1 ~R 4 The number of carbon atoms of the alkyl group represented by is preferably 1 to 20, more preferably 1 to 10, and still more preferably 1 to 5.

[0079] The piperidinium cation is, for example, a nitrogen-containing six-membered cyclic compound represented by the following general formula (3).

Chemical formula

[0080] The pyrrolidinium cation is, for example, a five-membered cyclic compound represented by the following general formula (4).

Chemical formula

[0081] The pyridinium cation is, for example, a compound represented by the following general formula (5). [Chemical formula] In formula (5), R 9 ~R 13 each independently represents an alkyl group having 1 to 20 carbon atoms, an alkoxyalkyl group represented by R-O-(CH 2 ) n - (wherein R represents a methyl group or an ethyl group, and n represents an integer of 1 to 4), or a hydrogen atom. The number of carbon atoms of the alkyl group represented by R 9 ~R 13 is preferably 1 to 20, more preferably 1 to 10, and still more preferably 1 to 5.

[0082] The imidazolium cation is, for example, a compound represented by the following general formula (6). [Chemical formula] In formula (6), R 14 ~R 18 each independently represents an alkyl group having 1 to 20 carbon atoms, an alkoxyalkyl group represented by R-O-(CH 2 ) n - (wherein R represents a methyl group or an ethyl group, and n represents an integer of 1 to 4), or a hydrogen atom. The number of carbon atoms of the alkyl group represented by R 14 ~R 18 is preferably 1 to 20, more preferably 1 to 10, and still more preferably 1 to 5.

[0083] The content of the ionic liquid may be 3% by mass or more, 5% by mass or more, or 10% by mass or more, and may be 30% by mass or less, 25% by mass or less, or 20% by mass or less, based on the total amount of the positive electrode mixture layer.

[0084] The positive electrode mixture layer 11 may further contain a conductive agent, a binder, and the like.

[0085] The conductive agent is not particularly limited, and may be a carbon material such as graphite, acetylene black, carbon black, carbon fiber, etc. The conductive agent may be a mixture of two or more of the above-described carbon materials.

[0086] The content of the conductive agent may be 0.1% by mass or more, 1% by mass or more, or 3% by mass or more, and may be 15% by mass or less, 10% by mass or less, or 8% by mass or less, based on the total amount of the positive electrode mixture layer.

[0087] The binder is not particularly limited, and may be a polymer containing tetrafluoroethylene, acrylic acid, maleic acid, ethyl methacrylate, etc. as monomer units (however, excluding the above-mentioned polymer A), a rubber such as styrene-butadiene rubber, isoprene rubber, acrylic rubber, etc.

[0088] The content of the binder may be 0.1% by mass or more, 1% by mass or more, or 3% by mass or more, and may be 15% by mass or less, 10% by mass or less, or 8% by mass or less, based on the total amount of the positive electrode mixture layer.

[0089] The thickness of the positive electrode mixture layer 11 may be 10 μm or more, 40 μm or more, 60 μm or more, or 80 μm or more, and may be 200 μm or less, 180 μm or less, or 160 μm or less.

[0090] In one embodiment, the electrolyte layer 8 contains a polymer (hereinafter also referred to as "polymer B"), oxide particles, and an electrolyte salt (hereinafter also referred to as "electrolyte salt B"). The pair of electrolyte layers 8, 8 may have the same composition as each other, or may have different compositions from each other.

[0091] Polymer B is a polymer (binder polymer) that serves as a matrix (forms a continuous phase) for holding other materials contained in the electrolyte layer 8. Polymer B preferably has a first monomer unit selected from the group consisting of tetrafluoroethylene and vinylidene fluoride. That is, polymer B may be polytetrafluoroethylene, polyvinylidene fluoride, or a copolymer of polytetrafluoroethylene and polyvinylidene fluoride.

[0092] Polymer B is preferably one or more polymers, and among the monomer units constituting the one or more polymers, preferably, a first monomer unit selected from the group consisting of ethylene tetrafluoride and vinylidene fluoride, and a second monomer unit selected from the group consisting of hexafluoropropylene, acrylic acid, maleic acid, ethyl methacrylate, and methyl methacrylate are included.

[0093] The first monomer unit and the second monomer unit may be included in one polymer to form a copolymer. That is, in one embodiment, the electrolyte layer 8 contains at least one copolymer containing both the first monomer unit and the second monomer unit. The copolymer may be a copolymer of vinylidene fluoride and hexafluoropropylene, a copolymer of vinylidene fluoride and maleic acid, a copolymer of vinylidene fluoride and methyl methacrylate, or the like. When the electrolyte layer 8 contains a copolymer, it may further contain other polymers.

[0094] The first monomer unit and the second monomer unit may be included in different polymers to form at least two polymers, a first polymer having the first monomer unit and a second polymer having the second monomer unit. That is, in one embodiment, the electrolyte layer 8 contains at least two or more polymers, a first polymer containing the first monomer unit and a second polymer containing the second monomer unit, as Polymer B. When the electrolyte layer 8 contains the first polymer and the second polymer, it may further contain other polymers.

[0095] The first polymer may be a polymer consisting only of the first monomer unit, or may be a polymer further having other monomer units in addition to the first monomer unit. The other monomer units may be oxygen-containing hydrocarbon structures such as ethylene oxide (-CH 2 CH 2 O-). The first polymer may be polytetrafluoroethylene, polyvinylidene fluoride, or a polymer having the oxygen-containing hydrocarbon structure introduced into the internal molecular structure thereof.

[0096] The second polymer may be a polymer consisting only of the second monomer unit, or may be a polymer further having other monomer units in addition to the second monomer unit. The other monomer units may have an oxygen-containing hydrocarbon structure such as ethylene oxide (-CH 2 CH 2 O-).

[0097] Examples of the combination of the first polymer and the second polymer include polyvinylidene fluoride and polyacrylic acid, polytetrafluoroethylene and polymethyl methacrylate, polyvinylidene fluoride and polymethyl methacrylate, and the like.

[0098] From the viewpoint of further improving the strength of the electrolyte layer 8, the content of the first monomer unit is preferably 5% by mass or more, more preferably 10% by mass or more, and still more preferably 20% by mass or more, based on the total amount of the monomer units constituting the polymer B. From the viewpoint of further improving the affinity with the ionic liquid when the electrolyte layer 8 contains the ionic liquid, the content of the first monomer unit is preferably 60% by mass or less, more preferably 40% by mass or less, and still more preferably 30% by mass or less, based on the total amount of the monomer units constituting the polymer B.

[0099] From the viewpoint of further improving the strength of the electrolyte layer 8, the content of the first monomer unit is preferably 50% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more, based on the total content of the first monomer unit and the second monomer unit. From the viewpoint of further improving the affinity with the ionic liquid when the electrolyte layer 8 contains the ionic liquid, the content of the first monomer unit is preferably 99% by mass or less, 98% by mass or less, 97% by mass or less, or 96% by mass or less, based on the total content of the first monomer unit and the second monomer unit.

[0100] When the electrolyte layer 8 contains an ionic liquid, the content of the second monomer unit is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more, based on the total amount of the monomer units constituting Polymer B, from the viewpoint of further improving the affinity with the ionic liquid. When considering the strength of the electrolyte layer 8, the content of the second monomer unit is preferably 50% by mass or less, more preferably 20% by mass or less, still more preferably 10% by mass or less, based on the total amount of the monomer units constituting Polymer B.

[0101] When the electrolyte layer 8 contains an ionic liquid, the content of the second monomer unit is preferably 1% by mass or more, 3% by mass or more, or 4% by mass or more, based on the total content of the first and second monomer units, from the viewpoint of further improving the affinity with the ionic liquid. When considering the strength of the electrolyte layer 8, the content of the second monomer unit is preferably 50% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, 10% by mass or less, or 5% by mass or less, based on the total content of the first and second monomer units.

[0102] When considering the strength of the electrolyte layer 8, the content of Polymer B is preferably 10% by mass or more, more preferably 15% by mass, still more preferably 20% by mass or more, particularly preferably 25% by mass or more, based on the total amount of the electrolyte layer. When considering the conductivity of the electrolyte layer 8, the content of Polymer B is preferably 40% by mass or less, more preferably 35% by mass or less, still more preferably 30% by mass or less, particularly preferably 28% by mass or less, based on the total amount of the electrolyte layer.

[0103] The oxide particles are, for example, particles of an inorganic oxide. The inorganic oxide may be, for example, an inorganic oxide containing Li, Mg, Al, Si, Ca, Ti, Zr, La, Na, K, Ba, Sr, V, Nb, B, Ge, etc. as constituent elements. The oxide particles are preferably SiO 2 、Al 2 O 3 、AlOOH, MgO, CaO, ZrO 2 、TiO 2, Li 7 La 3 Zr 2 O 12 , and BaTiO 3 It is at least one kind of particle selected from the group consisting of. Since the oxide particles have polarity, they promote the dissociation of the electrolyte in the electrolyte layer 8 and promote the amorphization of the polymer B to increase the diffusion rate of the cation component of the electrolyte.

[0104] From the viewpoint of improving the conductivity of the electrolyte layer 8, the average primary particle size (average particle size of primary particles) of the oxide particles is preferably 0.005 μm or more, more preferably 0.01 μm or more, and still more preferably 0.015 μm or more. From the viewpoint of thinning the electrolyte layer 8, the average primary particle size of the oxide particles is preferably 1 μm or less, more preferably 0.1 μm or less, and still more preferably 0.05 μm or less. The average primary particle size of the oxide particles can be measured by observing the oxide particles with a transmission electron microscope or the like.

[0105] The average particle size of the oxide particles is preferably 0.005 μm or more, more preferably 0.01 μm or more, and still more preferably 0.03 μm or more. The average particle size of the oxide particles is preferably 5 μm or less, more preferably 3 μm or less, and still more preferably 1 μm or less. The average particle size of the oxide particles is measured by the laser diffraction method and corresponds to the particle size at which the volume accumulation is 50% when the volume cumulative particle size distribution curve is drawn from the small particle size side.

[0106] The shape of the oxide particles may be, for example, massive or substantially spherical. From the viewpoint of facilitating the thinning of the electrolyte layer 8, the aspect ratio of the oxide particles is preferably 10 or less, more preferably 5 or less, and still more preferably 2 or less. The aspect ratio is defined as the ratio of the length in the major axis direction (the maximum length of the particle) to the length in the minor axis direction (the minimum length of the particle) in a scanning electron micrograph of the oxide particles. The length of the particle can be statistically calculated and obtained by using the above-mentioned photograph and commercially available image processing software (for example, image analysis software manufactured by Asahi Kasei Engineering Co., Ltd., A Image-kun (registered trademark)).

[0107] From the viewpoint of promoting the dissociation of the electrolyte, the content of the oxide particles is preferably 5% by mass or more, more preferably 7% by mass or more, and still more preferably 10% by mass or more based on the total amount of the electrolyte layer. From the viewpoint of improving the conductivity of the electrolyte layer 8, the content of the oxide particles is preferably 50% by mass or less, more preferably 40% by mass or less, and still more preferably 20% by mass or less based on the total amount of the electrolyte layer.

[0108] The electrolyte salt B contained in the electrolyte layer 8 may be the electrolyte salt exemplified as the electrolyte salt A contained in the positive electrode active material layer 11. The electrolyte salt B contained in the electrolyte layer 8 may be the same as or different from the electrolyte salt A contained in the positive electrode active material layer 11.

[0109] From the viewpoint of suitably producing the electrolyte layer 8, the content of the electrolyte salt B may be 10% by mass or more and may be 60% by mass or less based on the total amount of the electrolyte layer. From the viewpoint of increasing the conductivity of the electrolyte layer 8, the content of the electrolyte salt B is preferably 20% by mass or more based on the total amount of the electrolyte layer, and more preferably 30% by mass or more from the viewpoint of enabling the secondary battery 1 to be charged and discharged at a high discharge rate.

[0110] The electrolyte layer 8 may further contain an ionic liquid. In this case, the electrolyte salt B may exist in a state dissolved in the ionic liquid. The ionic liquid contained in the electrolyte layer 8 may be the one exemplified as the ionic liquid contained in the positive electrode active material layer 11.

[0111] From the viewpoint of suitably producing the electrolyte layer 8, the content of the ionic liquid may be 10% by mass or more and may be 60% by mass or less based on the total amount of the electrolyte layer. From the viewpoint of increasing the conductivity of the electrolyte layer 8 by increasing the content of the electrolyte salt and enabling the secondary battery 1 to be charged and discharged at a high discharge rate, the content of the ionic liquid is preferably 55% by mass or less, more preferably 50% by mass or less based on the total amount of the electrolyte layer.

[0112] When the electrolyte layer 8 contains an ionic liquid, the total content of the electrolyte salt B and the ionic liquid is preferably 10% by mass or more, more preferably 25% by mass or more, still more preferably 40% by mass or more, based on the total amount of the electrolyte layer, from the viewpoint of further improving the conductivity and suppressing the capacity reduction of the secondary battery 1. From the viewpoint of suppressing the decrease in the strength of the electrolyte layer 8, it is preferably 80% by mass or less, more preferably 70% by mass or less.

[0113] When the electrolyte layer 8 contains an ionic liquid, the concentration of the electrolyte salt B per unit volume of the ionic liquid is preferably 0.5 mol / L or more, more preferably 0.7 mol / L or more, still more preferably 1.0 mol / L or more, from the viewpoint of further improving the charge-discharge characteristics. Also, it is preferably 2.0 mol / L or less, more preferably 1.8 mol / L or less, still more preferably 1.6 mol / L or less.

[0114] The thickness of the electrolyte layer 8 is preferably 5 μm or more, more preferably 10 μm or more, from the viewpoint of enhancing the strength and further improving the safety. The thickness of the electrolyte layer 8 is preferably 200 μm or less, more preferably 150 μm or less, still more preferably 100 μm or less, from the viewpoints of further reducing the internal resistance of the secondary battery and further improving the high-current characteristics.

[0115] As shown in FIG. 3(a), a pair of electrolyte layers 8, 8 are laminated so as to sandwich the positive electrode 9. That is, one electrolyte layer 8 is laminated so as to be in contact with the positive electrode current collector 10, and the other electrolyte layer 8 is laminated so as to be in contact with the positive electrode mixture layer 11. The pair of electrolyte layers 8, 8 are arranged such that the edge portions 8e, 8e protrude from the edge portion of the positive electrode 9, and the protruding edge portions 8e, 8e of the pair of electrolyte layers 8, 8 are adhered to each other.

[0116] That is, in this positive electrode group 6, it can be said that the positive electrode 9 is accommodated between the pair of electrolyte layers 8, 8. In other words, it can also be said that the positive electrode 9 is arranged in the space formed by the pair of electrolyte layers 8, 8 whose edge portions are adhered to each other.

[0117] The length of the edges 8e, 8e of the pair of electrolyte layers 8, 8 (the length from the edge of the electrolyte layer 8) may be 0.5% or more, 1% or more, or 3% or more of the length or width of the electrolyte layers 8, 8, and may be 20% or less, 15% or less, or 10% or less. The area where the edges 8e, 8e of the pair of electrolyte layers 8, 8 are adhered may be, for example, 0.1% or more, 0.5% or more, or 1% or more of the area of the electrolyte layers 8, 8, and may be 20% or less, 15% or less, or 10% or less. The entire portion of the edges 8e, 8e of the pair of electrolyte layers 8, 8 that protrudes from the positive electrode 9 may be adhered to each other, or a part of the portion that protrudes from the positive electrode 9 may be adhered.

[0118] The edges 8e, 8e of the pair of electrolyte layers 8, 8 may be adhered to each other by crimping the edges 8e, 8e together. Preferably, they are adhered by melting a component (e.g., polymer B) contained in the electrolyte layer 8 by heating. Adhesion by heating can be performed, for example, by heat-sealing the pair of electrolyte layers 8, 8 (details will be described later).

[0119] In other embodiments, the edges 8e, 8e of the pair of electrolyte layers 8, 8 may be adhered to each other via another material (not shown) that aids adhesion, such as an adhesive. Such a material may be provided over the entire adhesion location of the edges 8e, 8e of the pair of electrolyte layers 8, 8, or may be provided at a part of the adhesion location. This can make the adhesion between the edges 8e, 8e stronger.

[0120] When using an adhesive as another material that aids adhesion, the adhesive may contain, for example, an acrylic resin, a urethane resin, or a silicone resin. The acrylic resin may be a resin containing monomer units derived from (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, glycidyl (meth)acrylate, (meth)acrylic acid, acrylamide, N-methylolacrylamide, etc.

[0121] The urethane resin may be made mainly from polyisocyanate and polyol. The polyisocyanate may be, for example, tolylene diisocyanate, diphenylmethane diisocyanate, etc. The polyol may be polyester polyol, polymer polyol, etc. As the silicone resin, commercially available products such as KR-100, KR-101-10, KR-130, KR-3700, KR-3701, X-40-3237, X-40-3240, X-40-3291-1 (the above, Shin-Etsu Chemical Co., Ltd.) etc. can be used.

[0122] Figure 3(b) is a schematic cross-sectional view taken along the line IIIb-IIIb in Figure 2. That is, Figure 3(b) is a schematic cross-sectional view of the negative electrode group 7. As shown in Figure 3(b), the negative electrode group 7 includes a pair of electrolyte layers 8, 8 and a negative electrode 12 disposed between the pair of electrolyte layers 8, 8. The edge portions 8e, 8e of the pair of electrolyte layers 8, 8 are adhered to each other. Since the electrolyte layer 8 is in the same manner as the electrolyte layer 8 in the positive electrode group 6 described above, the description thereof is omitted.

[0123] The negative electrode 12 includes a negative electrode current collector 13 and a negative electrode mixture layer 14 provided on one surface 13a of the negative electrode current collector 13. The negative electrode current collecting tab 5 shown in Figure 2 is provided so as to be connected to the negative electrode current collector 13.

[0124] The negative electrode current collector 13 may be formed of a metal such as aluminum, copper, nickel, stainless steel, or an alloy thereof. The negative electrode current collector 13 is preferably formed of copper from the viewpoints of ease of processing into a thin film and cost.

[0125] In one embodiment, the negative electrode mixture layer 14 contains a negative electrode active material, an organic solvent, and an electrolyte salt A.

[0126] The negative electrode active material may be a carbon material such as graphite or amorphous carbon, a metal material containing tin, silicon, etc., lithium titanate (Li 4 Ti 5 O 12 ), metallic lithium, etc.

[0127] The content of the negative electrode active material may be 60% by mass or more, 65% by mass or more, or 70% by mass or more based on the total amount of the negative electrode binder layer. The content of the negative electrode active material may be 99% by mass or less, 95% by mass or less, or 90% by mass or less based on the total amount of the negative electrode binder layer.

[0128] The types and contents of the organic solvent and electrolyte salt A contained in the negative electrode binder layer 14 may be the same as those described above for the organic solvent and electrolyte salt A contained in the positive electrode binder layer 11, respectively. The organic solvent and electrolyte salt A contained in the negative electrode binder layer 14 may be the same as or different from the organic solvent and electrolyte salt A contained in the positive electrode binder layer 11, respectively.

[0129] From the viewpoint of suppressing leakage of the organic solvent from the secondary battery 1 and improving the adhesion between the negative electrode current collector 13 and the negative electrode binder layer 14, the negative electrode binder layer 14 may further contain a polymer (polymer A) capable of gelling the organic solvent. The types and contents of the polymer A contained in the negative electrode binder layer 14 may be the same as those described above for the polymer A contained in the positive electrode binder layer 11. The polymer A contained in the negative electrode binder layer 14 may be the same as or different from the polymer A contained in the positive electrode binder layer 11.

[0130] The negative electrode binder layer 14 may further contain an ionic liquid. The types and contents of the ionic liquid contained in the negative electrode binder layer 14 may be the same as those described above for the ionic liquid contained in the positive electrode binder layer 11. The ionic liquid contained in the negative electrode binder layer 14 may be the same as or different from the ionic liquid contained in the positive electrode binder layer 11.

[0131] The negative electrode binder layer 14 may further contain a conductive agent, a binder, etc. The types and contents of the conductive agent and binder contained in the negative electrode binder layer 14 may be the same as those described above for the conductive agent and binder contained in the positive electrode binder layer 11, respectively. The conductive agent and binder contained in the negative electrode binder layer 14 may be the same as or different from the conductive agent and binder contained in the positive electrode binder layer 11, respectively.

[0132] The thickness of the negative electrode mixture layer 14 may be 10 μm or more, 20 μm or more, 40 μm or more, or 60 μm or more, and may be 150 μm or less, 130 μm or less, or 110 μm or less.

[0133] As shown in FIG. 3(b), also in the negative electrode group 7, similar to the positive electrode group 6 described above, the pair of electrolyte layers 8, 8 are laminated so as to sandwich the positive electrode 9. That is, one electrolyte layer 8 is laminated so as to contact the negative electrode current collector 13, and the other electrolyte layer 8 is laminated so as to contact the negative electrode mixture layer 14. The pair of electrolyte layers 8, 8 are arranged such that the edge portions 8e, 8e protrude from the edge of the negative electrode 12, and the edge portions 8e, 8e of the protruding pair of electrolyte layers 8, 8 are adhered to each other.

[0134] In the negative electrode group 7, the method of adhering the edge portions 8e, 8e of the pair of electrolyte layers 8, 8 may be the same as the method of adhering the edge portions 8e, 8e of the pair of electrolyte layers 8, 8 in the positive electrode group 6.

[0135] In the positive electrode group 6 and the negative electrode group 7 in the secondary battery 1, since an organic solvent is likely to be retained in the electrode mixture layer, the interfaces between the electrode active material and the electrolyte salt which is an ion conduction component, and between the electrode mixture layer and the electrolyte layer are each favorably formed by the organic solvent, and the battery characteristics such as the cycle characteristics of the secondary battery 1 including these electrode groups can be improved.

[0136] The secondary battery 1 described above can be manufactured from, for example, a battery member including the positive electrode group 6 or the negative electrode group 7.

[0137] FIG. 4 is a schematic cross-sectional view showing an embodiment of a battery member. FIG. 4(a) is a schematic cross-sectional view showing an embodiment of a positive electrode member, and FIG. 4(b) is a schematic cross-sectional view showing an embodiment of a negative electrode member. The battery member according to one embodiment includes a pair of base materials, a pair of electrolyte layers provided between the pair of base materials and having their edge portions adhered to each other, and an electrode disposed between the pair of electrolyte layers.

[0138] When the electrode is the positive electrode, one embodiment of the battery member is the positive electrode member 15 shown in Fig. 4(a). The positive electrode member 15 includes a pair of base materials 16, 16, a pair of electrolyte layers 8, 8 provided between the pair of base materials 16, 16 and having their edge portions 8e, 8e adhered to each other, and a positive electrode 9 disposed between the pair of electrolyte layers 8, 8. When the electrode is the negative electrode, one embodiment of the battery member is the negative electrode member 17 shown in Fig. 4(b). The negative electrode member 17 includes a pair of base materials 16, 16, a pair of electrolyte layers 8, 8 provided between the pair of base materials 16, 16 and having their edge portions 8e, 8e adhered to each other, and a negative electrode 12 disposed between the pair of electrolyte layers 8, 8. The forms of the electrolyte layer 8, the positive electrode 9, and the negative electrode 12 are the same as those of these components in the positive electrode group 6 and the negative electrode group 7 described above, respectively.

[0139] The base material 16 is formed of, for example, a resin. More specifically, the base material 16 may be a film made of a resin (general-purpose engineering plastic) such as polypropylene, polyethylene, polyvinyl chloride, polyethylene terephthalate, polytetrafluoroethylene, polyimide, polyethersulfone, or polyetherketone. The pair of base materials 16, 16 may be formed of the same material as each other or may be formed of different materials from each other.

[0140] From the viewpoints of ensuring the strength during the production of the electrolyte sheet described later and further suppressing the volatilization of the organic solvent contained in the electrode mixture layer, the thickness of the base material 16 is preferably 5 μm or more, more preferably 10 μm or more, and still more preferably 25 μm or more. From the viewpoint of reducing the volume of the battery member, the thickness of the base material 16 is preferably 100 μm or less, more preferably 50 μm or less, and still more preferably 40 μm or less.

[0141] In the positive electrode member 15 and the negative electrode member 17, as shown in Fig. 4(a) and Fig. 4(b), it is preferable that the base material 16 covers the entire electrolyte layer 8. More specifically, it is preferable that the base material 16 covers the entire surface 8a on the side opposite to the positive electrode 9 or the negative electrode 12 in the electrolyte layer 8. By the base material 16 covering the entire surface 8a on the side opposite to the positive electrode 9 of the electrolyte layer 8, the volatilization of the organic solvent from the positive electrode mixture layer 11 or the negative electrode mixture layer 14 can be further suppressed.

[0142] In this battery member (the positive electrode member 15 and the negative electrode member 17), the electrode (the positive electrode 9 or the negative electrode 12) is sandwiched and laminated between a pair of base materials 16, 16 and a pair of electrolyte layers 8, 8. Further, the edges 8e, 8e of the pair of electrolyte layers 8, 8 are adhered to each other. The adhesion method between the edges 8e, 8e of the pair of electrolyte layers 8, 8 is the same as the above-described modes of the positive electrode group 6 and the negative electrode group 7. That is, in this battery member, it can be said that the electrode is accommodated between a pair of base materials 16, 16 and a pair of electrolyte layers 8, 8. In other words, in this battery member, it can also be said that the electrode is disposed in a space formed by a pair of electrolyte layers 8, 8 whose edges are adhered to each other, and the pair of electrolyte layers 8, 8 are covered by the base materials 16, 16. For this reason, the volatilization of the organic solvent contained in the electrode mixture layer (the positive electrode mixture layer 11 or the negative electrode mixture layer 14) is suppressed.

[0143] The electrode group 2A in the secondary battery 1 can be manufactured by laminating the above-described positive electrode member 15 and negative electrode member 17 by laminating or the like after peeling off all the base materials 16. When laminating the positive electrode member 15 and the negative electrode member 17 from which the base material 16 has been peeled off, they may be laminated so that the positive electrode mixture layer 11 and the negative electrode mixture layer 14 face each other via the electrolyte layer 8. The secondary battery 1 is obtained by accommodating the electrode group 2A in the battery exterior body 3. When accommodating the electrode group 2A in the battery exterior body 3, it is not necessary to additionally inject an electrolytic solution (organic solvent and electrolyte salt) into the battery exterior body 3.

[0144] When manufacturing the secondary battery 1 using this battery member, since the volatilization of the organic solvent is suppressed during the manufacture and storage of the battery member, the step of additionally injecting an electrolytic solution (organic solvent and electrolyte salt) during the manufacture of the secondary battery 1 can be omitted. Therefore, the manufacturing time of the secondary battery 1 can be shortened.

[0145] The battery member described above can be manufactured, for example, by the following method. A method for manufacturing a battery member according to an embodiment includes a step (a) of obtaining a laminate including a pair of base materials, a pair of electrolyte layers provided between the pair of base materials, and an electrode disposed between the pair of electrolyte layers, and a step (b) of bonding the edges of the pair of electrolyte layers to each other. Since the manufacturing methods of the positive electrode member 15 and the negative electrode member 17 may be the same as each other, the manufacturing method of the battery member will be described below without distinguishing between the positive electrode member 15 and the negative electrode member 17.

[0146] In step (a), in one embodiment, a composition containing an organic solvent and an electrolyte salt (hereinafter also referred to as "electrolyte composition") is added to an electrode active material layer containing an electrode active material provided on at least one surface of a current collector to form an electrode binder layer (step (w1)), and an electrode is disposed between a pair of electrolyte layers (step (w2)) in this order. That is, the method for manufacturing a battery member according to an embodiment includes step (w1), step (w2), and step (b) in this order.

[0147] FIG. 5 is a schematic cross-sectional view showing a method for manufacturing a battery member according to an embodiment. In step (w1) of this method, first, an electrode laminate 20 including a current collector 18 and an electrode active material layer 19 containing an electrode active material provided on one surface 18a of the current collector 18 is prepared (FIG. 5(a)). The electrode laminate 20 can be produced, for example, by preparing a slurry in which a material containing an electrode active material, a conductive agent, a binder, etc. is dispersed in a dispersion medium, applying the slurry to one surface 18a of the current collector 18, and then volatilizing the dispersion medium. The dispersion medium is not particularly limited, and may be an aqueous solvent such as water, a mixed solvent of alcohol and water, or an organic solvent such as N-methyl-2-pyrrolidone (NMP).

[0148] Next, an electrolyte composition 21 containing an organic solvent and an electrolyte salt A is added into the electrode active material layer 19 to form an electrode binder layer 22 (FIGS. 5(b) and 5(c)). The method of adding the electrolyte composition 21 into the electrode active material layer 19 can also be referred to as a method of impregnating the electrode active material layer 19 with the electrolyte composition 21. The method of adding the electrolyte composition 21 into the electrode active material layer 19 may be, for example, a method by dropping, a method by coating using a comma coater or a die coater, etc., a method by printing, a method by spraying, a method by dip coating in which the electrode laminate 20 is immersed in the electrolyte composition 21, and the like. The obtained electrode binder layer 22 contains an electrode active material and the electrolyte composition 21 disposed (filled) between the electrode active materials. Thereby, an electrode 23 (positive electrode 9 or negative electrode 12) having a current collector 18 and an electrode binder layer 22 provided on one surface 18a of the current collector 18 is obtained.

[0149] The contents of the organic solvent and the electrolyte salt A in the electrolyte composition 21 may be adjusted so as to substantially coincide with the desired contents of the respective components in the electrode binder layer 22.

[0150] Next, in step (w2), two electrolyte sheets 24 each including a base material 16 and an electrolyte layer 8 provided on one surface 16a of the base material 16 are prepared, and an electrode 23 is disposed between a pair of electrolyte layers 8, 8 in the two electrolyte sheets 24, 24 (FIG. 5(d)). Thereby, a laminate 25 including a pair of base materials 16, 16, a pair of electrolyte layers 8, 8 provided between the pair of base materials 16, 16, and an electrode 23 provided between the pair of electrolyte layers 8, 8 is obtained. At this time, the pair of electrolyte sheets 24, 24 are arranged such that the edges 8e, 8e of the electrolyte layers 8, 8 protrude from the edges 22e of the electrode binder layer 22. As a result, the edges 8e, 8e of the pair of electrolyte layers 8, 8 face each other.

[0151] In one embodiment, the electrolyte sheet 24 is produced by dispersing a material (solid content) used for the electrolyte layer 8 in a dispersion medium to obtain a slurry, then applying this onto one surface 16a of the base material 16, and then volatilizing the dispersion medium. The dispersion medium used at this time is preferably water, NMP, toluene, or the like.

[0152] Subsequently, in step (b), in the pair of electrolyte layers 8, 8, the opposing edges 8e, 8e are bonded to each other (FIG. 5(e)). Thereby, the battery member 26 (the positive electrode member 15 or the negative electrode member 17) is obtained.

[0153] The method of bonding the edges 8e, 8e of the pair of electrolyte layers 8, 8 may be, for example, a method of applying pressure to the edges 8e, 8e of the pair of electrolyte layers 8, 8 to bond them, that is, a method of crimping. At this time, crimping may be performed via the pair of base materials 16, 16 in order to bond the edges 8e, 8e of the pair of electrolyte layers 8, 8 to each other.

[0154] The pressure during crimping may preferably be 100 Pa or more, more preferably 150 Pa or more, still more preferably 200 Pa or more, and preferably 1 MPa or less, more preferably 0.5 MPa or less, still more preferably 0.1 MPa or less, from the viewpoint of further enhancing the adhesiveness between the electrolyte layers 8, 8 and between the base material 16 and the electrolyte layer 8.

[0155] The crimping time may preferably be 0.5 seconds or more, more preferably 1 second or more, still more preferably 1.5 seconds or more, from the viewpoint of further enhancing the adhesiveness between the electrolyte layers and between the base material and the electrolyte layer. The crimping time may preferably be 10 seconds or less, more preferably 8 seconds or less, still more preferably 5 seconds or less, from the viewpoint of shortening the manufacturing time of the secondary battery 1.

[0156] The method of crimping the edges 8e, 8e of the electrolyte layers 8, 8 is preferably a method of crimping while heating (heat sealing) from the viewpoint of bonding the edges 8e, 8e more firmly to each other. Thereby, the materials (for example, polymer B) contained in the pair of electrolyte layers 8, 8 are melted, and the pair of electrolyte layers 8, 8 are bonded more firmly.

[0157] The heating temperature during heat sealing is preferably 80°C or higher, more preferably 100°C or higher, and still more preferably 120°C or higher, from the viewpoint of further enhancing the adhesiveness between the electrolyte layers and between the base material and the electrolyte layer. The heating temperature is preferably 200°C or lower, more preferably 180°C or lower, and still more preferably 160°C or lower, from the viewpoint of the thermal stability of the base material and the electrolyte layer. The pressure and sealing time during heat sealing may be the same as the pressure and crimping time during the above-described crimping.

[0158] In the method of adhering the edges 8e, 8e of the pair of electrolyte layers 8, 8, a material for assisting the adhesion of the edges 8e, 8e may be disposed at the adhesion location, and the edges 8e, 8e may be adhered through this material. The material for assisting adhesion is, for example, an adhesive. In the method of adhering the edges 8e, 8e of the pair of electrolyte layers 8, 8, the pair of electrolyte layers 8, 8 may be crimped after disposing other materials (such as adhesives) for assisting adhesion described above.

[0159] The length of the edges 8e, 8e of the pair of electrolyte layers 8, 8 to be adhered (the length from the edge of the electrolyte layer 8) may be 0.5% or more, 1% or more, or 3% or more of the length or width of the electrolyte layers 8, 8, and may be 20% or less, 15% or less, or 10% or less. The area of the edges 8e, 8e of the pair of electrolyte layers 8, 8 to be adhered may be, for example, 0.1% or more, 0.5% or more, or 1% or more of the area of the electrolyte layers 8, 8, and may be 20% or less, 15% or less, or 10% or less. In step (b), for the edges 8e, 8e of the pair of electrolyte layers 8, 8, they may be adhered such that the entire portion protruding from the electrode 23 is adhered to each other, or they may be adhered such that a part of the portion protruding from the electrode 23 is adhered.

[0160] In other embodiments, step (a) includes a step (x1) of disposing an electrode laminate including a current collector and an electrode active material layer provided on at least one surface of the current collector and containing an electrode active material between a pair of electrolyte layers, and a step (x2) of forming an electrode binder layer by adding a composition containing an organic solvent and an electrolyte salt to the electrode active material layer, in this order. That is, the method for manufacturing a battery member according to one embodiment includes step (x1), step (x2), and step (b) in this order.

[0161] FIG. 6 is a schematic cross-sectional view showing a method for manufacturing a battery member according to another embodiment. In step (x1) of this method, first, an electrode laminate 20 including a current collector 18 and an electrode active material layer 19 containing an electrode active material provided on one surface 18a of the current collector 18 is prepared (FIG. 6(a)).

[0162] Next, two electrolyte sheets 24 each including a base material 16 and a pair of electrolyte layers 8, 8 provided on one surface 16a of the base material 16 are prepared, and the electrode laminate 20 is disposed between the pair of electrolyte layers 8, 8 in the two electrolyte sheets 24, 24 (FIG. 6(b)). Thereby, a laminate 27 including a pair of base materials 16, 16, a pair of electrolyte layers 8, 8 provided between the pair of base materials 16, 16, and an electrode laminate 20 provided between the pair of electrolyte layers 8, 8 is obtained. At this time, the two electrolyte sheets 24, 24 are disposed such that the edges 8e, 8e of the electrolyte layers 8, 8 protrude from the edge 19e of the electrode active material layer 19. As a result, the edges 8e, 8e of the pair of electrolyte layers 8, 8 face each other.

[0163] Next, in step (x2), for example, using an injection device 28, an electrolytic solution composition 21 containing an organic solvent and an electrolyte salt A is added into the electrode active material layer 19 to form an electrode binder layer 22 (FIGS. 6(c) and 6(d)). The method of adding the electrolytic solution composition 21 into the electrode active material layer 19 may be, in addition to injection by the injection device 28, a method of dropping the electrolytic solution composition from between the pair of electrolyte layers 8, 8, a coating method, a spraying method, or the like.

[0164] In step (x2), before adding the electrolyte composition 21 into the electrode active material layer 19, a part of the edges 8e, 8e of the pair of electrolyte layers 8, 8 may be adhered. In this case, the electrolyte composition 21 may be added into the electrode active material layer 19 from the non - adhered portions of the edges 8e, 8e.

[0165] The obtained electrode mixture layer 22 contains an electrode active material and the electrolyte composition 21 disposed (filled) between the electrode active materials. Thereby, as shown in FIG. 6(d), a laminate 25 is obtained which includes a pair of base materials 16, 16, a pair of electrolyte layers 8, 8 provided between the pair of base materials 16, 16, and an electrode 23 provided between the pair of electrolyte layers 8, 8.

[0166] Subsequently, in step (b), in the pair of electrolyte layers 8, 8, the mutually facing edges 8e, 8e are adhered to each other (FIG. 6(e)). When a part of the edges 8e, 8e of the pair of electrolyte layers 8, 8 are adhered in step (x2), the non - adhered portions are adhered. The method of adhering the edges 8e, 8e of the pair of electrolyte layers 8, 8 may be the same as the method described in the above - mentioned embodiment. Thereby, the battery member 26 is obtained.

[0167] In another embodiment, step (a) includes a step (y1) of disposing an electrode laminate including a current collector and an electrode active material layer provided on at least one surface of the current collector and containing an electrode active material, on the first electrolyte layer of a first electrolyte sheet having a first base material and a first electrolyte layer provided on one surface of the first base material; a step (y2) of adding a composition containing an organic solvent and an electrolyte salt to the electrode active material layer to form an electrode mixture layer; and a step (y3) of laminating a second electrolyte sheet having a second base material and a second electrolyte layer provided on one surface of the second base material such that the second electrolyte layer faces the electrode mixture layer side, in this order. That is, the method for manufacturing a battery member according to one embodiment includes steps (y1), (y2), (y3), and (b) in this order.

[0168] FIG. 7 is a schematic cross-sectional view showing a method for manufacturing a battery member according to another embodiment. In step (y1) of this method, first, an electrode laminate 20 including a current collector 18 and an electrode active material layer 19 containing an electrode active material provided on one surface 18a of the current collector 18, a first base material 16, and a first electrolyte sheet 24 including a first electrolyte layer 8 provided on one surface 16a of the first base material 16 are prepared, and the electrode laminate 20 is disposed on one surface 8b of the first electrolyte layer 8 in the first electrolyte sheet 24 (FIG. 7(a)). At this time, the electrode laminate 20 is disposed such that the edge 8e of the first electrolyte layer 8 in the first electrolyte sheet 24 protrudes from the edge 19e of the electrode active material layer 19.

[0169] In FIG. 7(a), the electrode laminate 20 is disposed such that the current collector 18 contacts the one surface 8b of the electrolyte layer 8, but the electrode laminate 20 may be disposed such that the electrode active material layer 19 contacts the one surface 8b of the electrolyte layer 8.

[0170] Next, in step (y2), an electrolyte composition 21 containing an organic solvent and an electrolyte salt A is added into the electrode active material layer 19 to form an electrode binder layer 22 (FIGS. 7(b) and 7(c)). The method of adding the electrolyte composition 21 into the electrode active material layer 19 may be the same as the method in step (w1) according to the above-described embodiment. The obtained electrode binder layer 22 includes an electrode active material and the electrolyte composition 21 disposed (filled) between the electrode active materials. Thereby, as shown in FIG. 7(c), an electrode 23 having the current collector 18 and the electrode binder layer 22 provided on one surface 18a of the current collector 18 is obtained.

[0171] Next, in step (y3), a second electrolyte sheet 24 including a second base material 16 and a second electrolyte layer 8 provided on one surface 16a of the second base material 16 is prepared, and the second electrolyte sheet 24 is laminated on the electrode 23 such that the second electrolyte layer 8 in the second electrolyte sheet 24 faces the electrode mixture layer 22 side (FIG. 7(d)). When laminating the second electrolyte sheet 24, for example, as shown in FIG. 7(d), the second electrolyte sheet 24 may be laminated such that the second electrolyte layer 8 contacts the surface 22a of the electrode mixture layer 22 opposite to the current collector 18. Thereby, a laminate 25 including a pair of base materials 16, 16, a pair of electrolyte layers 8, 8 provided between the pair of base materials 16, 16, and an electrode 23 provided between the pair of electrolyte layers 8, 8 is obtained. At this time, by arranging the second electrolyte sheet 24 such that the edge portion 8e of the second electrolyte layer 8 protrudes from the edge portion 22e of the electrode mixture layer 22, the edge portions 8e, 8e of the pair of electrolyte layers 8, 8 face each other.

[0172] In step (y1), when the electrode laminate 20 is arranged such that the electrode active material layer 19 contacts one surface 8b of the electrolyte layer 8, in step (y3), the second electrolyte sheet 24 may be laminated such that the second electrolyte layer 8 contacts the surface of the current collector 18 opposite to the electrode mixture layer 22.

[0173] Subsequently, in step (b), in the pair of electrolyte layers 8, 8, the edge portions 8e, 8e facing each other are bonded (FIG. 7(e)). The method of bonding the edge portions 8e, 8e of the pair of electrolyte layers 8, 8 may be the same as the method in the above-described embodiment. Thereby, the battery member 26 is obtained.

[0174] In the method for manufacturing a battery member according to each of the embodiments described above, when the electrode mixture layer in the battery member contains the above-described polymer A, the electrolytic solution composition contains the above-described polymer A, and after step (b), a step (c) of gelling the electrolytic solution composition may be further provided. That is, another embodiment of the method for manufacturing a battery member may include step (w1), step (w2), step (b), and step (c) in this order, may include step (x1), step (x2), step (b), and step (c) in this order, or may include step (y1), step (y2), step (y3), step (b), and step (c) in this order.

[0175] In step (c), the method of gelling the organic solvent with polymer A may be a method by heating. In step (c), for example, after adhering the edges of a pair of electrolyte layers to each other, the obtained battery member is heated by a constant temperature bath or a dryer to gel the organic solvent.

[0176] The heating temperature in step (c) may be a temperature at which polymer A gels. For example, it may be 40°C or higher, 50°C or higher, or 55°C or higher, and may be 120°C or lower, 100°C or lower, or 80°C or lower. The heating time may be, for example, 1 hour or longer, 2 hours or longer, or 3 hours or longer, and may be 10 hours or shorter, 8 hours or shorter, or 6 hours or shorter.

[0177] In another embodiment, the electrolytic solution composition used in step (a) further contains a polymerizable compound in addition to the organic solvent and the electrolyte salt A. In this case, after step (b), a step (d) of polymerizing the polymerizable compound in the electrode mixture layer may be further included. That is, another embodiment of the method for manufacturing a battery member may include step (w1), step (w2), step (b), and step (d) in this order, may include step (x1), step (x2), step (b), and step (d) in this order, or may include step (y1), step (y2), step (y3), step (b), and step (d) in this order.

[0178] In this embodiment, the electrolytic solution composition contains an organic solvent, an electrolyte salt A, and a polymerizable compound, and preferably further contains a polymerization initiator that initiates the polymerization of the polymerizable compound.

[0179] The polymerizable compound is at least one compound selected from the group consisting of monomers and oligomers that can form the above polymer A by polymerization. That is, the polymerizable compound is a compound (monomer or oligomer) that can become a polymer (polymer A) capable of gelling the organic solvent by polymerization.

[0180] The polymerizable compound may be at least one compound selected from the group consisting of vinylidene fluoride, hexafluoropropylene, acrylonitrile, methyl methacrylate, N-isopropylacrylamide, methyl acrylate, styrene, pentaerythritol tetraacrylate, diallyldimethylammonium-bis(trifluoromethanesulfonyl)imide, 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl acrylate, 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluoroheptyl methacrylate, (ethylene glycol) methacrylate, trimethylolpropane triacrylate, isoprene monooxide, ethylene glycol diglycidyl ether, and oligomers thereof.

[0181] The content (total content) of the polymerizable compound in the electrolytic solution composition may be adjusted to substantially match the desired content of the polymer A in the electrode binder layer.

[0182] The polymerization initiator may be appropriately selected from known polymerization initiators. The polymerization initiator may be, for example, an azo compound-based polymerization initiator, an organic peroxide-based polymerization initiator, etc., or may be a polymerization initiator other than these.

[0183] Examples of azo compound polymerization initiators include 2,2'-azobis(isobutyronitrile) (AIBN), 1-[(1-cyano-1-methylethyl)azo]formamide, 2,2'-azobis(N-butyl-2-methylpropionamide), 2,2'-azobis(N-cyclohexyl-2-methylpropionamide), 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), and the like.

[0184] Examples of organic peroxide polymerization initiators include benzoyl peroxide (BPO), tert-butyl peroxyacetate, 2,2-di-(tert-butylperoxy)butane, tert-butyl peroxybenzoate, n-butyl-4,4-di-(tert-butylperoxy)valerate, di-(2-tert-butylperoxyisopropyl)benzene, dicumyl peroxide, di-tert-hexyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butyl cumyl peroxide, di-tert-butyl peroxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, tert-butyl hydroperoxide, tert-butyltrimethylsilyl peroxide, and the like.

[0185] The content of the polymerization initiator in the electrolytic solution composition may be, for example, 0.1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the content of the polymerizable compound.

[0186] In step (d), the polymerizable compound in the electrode mixture layer is polymerized. As a result, polymer A is formed from the polymerizable compound, and the organic solvent can be gelled by polymer A.

[0187] The method of polymerizing the polymerizable compound may be, for example, a method of polymerizing by applying heat (heat polymerization). The heating temperature and heating time may be appropriately set according to the type of the polymerizable compound. The heating temperature may be, for example, 30 °C or higher, 40 °C or higher, or 50 °C or higher, and may be 100 °C or lower, 90 °C or lower, or 80 °C or lower. The heating time may be, for example, 1 hour or longer, 3 hours or longer, or 5 hours or longer, and may be 48 hours or shorter, 32 hours or shorter, or 16 hours or shorter. The method of polymerizing may also be a method of polymerizing by irradiating light (photo polymerization).

[0188] The electrode groups (positive electrode group and negative electrode group) and battery members (positive electrode member and negative electrode member) described above can be made into long electrode groups or battery members as a modification. The long electrode group is an electrode group in which a pair of electrolyte layers 8, 8 and a positive electrode 9 or a negative electrode 12 are each formed in a long shape in the positive electrode group 6 or negative electrode group 7 described above. Also in the long electrode group, a pair of electrolyte layers are arranged so as to sandwich the long electrode, and the edges of the pair of electrolyte layers are adhered to each other. That is, the positive electrode group 6 and negative electrode group 7 shown in FIGS. 3(a) and 3(b) may be long in a direction perpendicular to the cross section shown in FIGS. 3(a) and 3(b), for example.

[0189] The long battery member is a battery member in which a pair of base materials 16, 16, a pair of electrolyte layers 8, 8, a positive electrode 9, and a negative electrode 12 are each formed in a long shape in the positive electrode member 15 and negative electrode member 17 described above. Also in the long battery member, a pair of base materials and a pair of electrolyte layers are arranged so as to sandwich the long electrode, and the edges of the pair of electrolyte layers are adhered to each other. That is, the positive electrode member 15 and negative electrode member 17 shown in FIGS. 4(a) and 4(b) may be long in a direction perpendicular to the cross section shown in FIGS. 4(a) and 4(b), for example.

[0190] In the long-strip-shaped electrode group and the battery member, on two sides which are the long sides, the edges of a pair of electrolyte layers may be adhered to each other. That is, on the two short sides of the long-strip-shaped electrode group and the battery member, the edges do not necessarily need to be adhered to each other. In the long-strip-shaped electrode group and the battery member, even if the edges of the pair of electrolyte layers are adhered only on the two long sides, the volatilization of the organic solvent from the electrode paste layer can be sufficiently suppressed.

[0191] The long-strip-shaped battery member can be manufactured by the same method as the manufacturing method of the battery member 26 described above, and the above-described steps (a) and (b) can be continuously performed. For example, two long-strip-shaped electrolyte sheets each including a pair of base materials and a pair of electrolyte layers provided on one surface of the pair of base materials are prepared, and while arranging a long-strip-shaped electrode between the pair of electrolyte layers of the two electrolyte sheets, these are laminated, and by sequentially adhering the edges of the pair of electrolyte layers from the laminated portion, a long-strip-shaped battery member can be obtained. Arranging a long-strip-shaped electrode between a pair of electrolyte layers includes adding the above-described electrolyte composition to the electrode active material layer to form an electrode while arranging a long-strip-shaped electrode laminate between the pair of electrolyte layers.

[0192] The long-strip-shaped battery member can be cut to a predetermined size to form a rectangular battery member. Further, for the long-strip-shaped positive electrode member and the long-strip-shaped negative electrode member, by laminating and winding them while peeling off a pair of base materials respectively, an electrode group for manufacturing a wound secondary battery can be obtained.

[0193] Next, another embodiment of the electrode group 2 of the secondary battery shown in FIG. 1 will be described. FIG. 8 is a schematic cross-sectional view showing another embodiment of the electrode group of the secondary battery. In FIG. 8, the same reference numerals as those of the electrode group 2A shown in FIG. 3 are given, and redundant descriptions are omitted. As shown in FIG. 8, the difference between the secondary battery in another embodiment and the secondary battery in the above-described embodiment is that the electrode group 2B further includes a double-sided coated positive electrode group 33 including a double-sided coated positive electrode 31 in which a positive electrode paste layer 11 is provided on both surfaces of a positive electrode current collector 10, and a double-sided coated negative electrode group 34 including a double-sided coated negative electrode 32 in which a negative electrode paste layer 14 is provided on both surfaces of a negative electrode current collector 13.

[0194] The electrode group 2B can be regarded as including the above-described positive electrode group 6 (a single-sided coated positive electrode group), a double-sided coated negative electrode group 34, a double-sided coated positive electrode group 33, and the above-described negative electrode group 7 (a single-sided coated negative electrode group) in this order. The double-sided coated positive electrode group 33 includes a pair of electrolyte layers 8, 8 and a double-sided coated positive electrode 31 disposed between the pair of electrolyte layers 8, 8. In the double-sided coated positive electrode group 33, the edge portions 8e, 8e of the pair of electrolyte layers 8, 8 are adhered to each other. The double-sided coated negative electrode group 34 includes a pair of electrolyte layers 8, 8 and a double-sided coated negative electrode 32 disposed between the pair of electrolyte layers 8, 8. In the double-sided coated negative electrode group 34, the edge portions 8e, 8e of the pair of electrolyte layers 8, 8 are adhered to each other.

[0195] The double-sided coated positive electrode group 33 and the double-sided coated negative electrode group 34 can be manufactured using a battery member including a pair of base materials, an electrolyte layer provided between the pair of base materials with the edge portions adhered to each other, and a double-sided coated electrode disposed between the pair of electrolyte layers. This battery member can be manufactured by a method similar to that in the manufacturing method of the battery member of the above-described embodiment, except that an electrode mixture layer is formed on both surfaces of the current collector.

[0196] FIG. 9 is a schematic cross-sectional view showing still another embodiment of the electrode group of the secondary battery. In FIG. 9, the same reference numerals as those of the electrode group 2A shown in FIG. 3 are given, and redundant descriptions are omitted. As shown in FIG. 9, the difference between the secondary battery in another embodiment and the secondary battery in the above-described embodiment is that the electrode group 2C includes a bipolar electrode group 36 including a bipolar electrode 35.

[0197] The electrode group 2C can be regarded as including the above-described positive electrode group 6, the bipolar electrode group 36, and the above-described negative electrode group 7 in this order. The bipolar electrode group 36 includes a pair of electrolyte layers 8, 8 and a bipolar electrode 35 disposed between the pair of electrolyte layers 8, 8. In the bipolar electrode group 36, the edge portions 8e, 8e of the pair of electrolyte layers 8, 8 are adhered to each other.

[0198] The bipolar electrode 35 includes a bipolar electrode current collector 37, a positive electrode mixture layer 11 provided on the surface of the bipolar electrode current collector 37 on the negative electrode group 7 side, and a negative electrode mixture layer 14 provided on the surface of the bipolar electrode current collector 37 on the positive electrode group 6 side.

[0199] The bipolar electrode current collector 37 is formed of, for example, a single metal such as aluminum, stainless steel, or titanium, or a clad material formed by roll-bonding aluminum and copper or stainless steel and copper.

[0200] The bipolar electrode group 36 can be manufactured using a battery member including a pair of base materials, an electrolyte layer provided between the pair of base materials and having its edges adhered to each other, and a bipolar electrode disposed between the pair of electrolyte layers. This battery member can be manufactured by a method similar to that of the battery member manufacturing method of the above-described embodiment, except that a positive electrode mixture layer is formed on one surface of the bipolar electrode current collector and a negative electrode mixture layer is formed on the other surface of the bipolar electrode current collector.

[0201] Also, in the electrode groups according to the other embodiments described above, since an organic solvent is likely to be retained in the electrode mixture layer, the interfaces between the electrode active material and the electrolyte salt which is an ion conduction component, and between the electrode mixture layer and the electrolyte layer are each favorably formed, and the battery performance such as the cycle characteristics of the secondary battery including these electrode groups can be improved.

[0202] Moreover, the battery members for manufacturing the double-sided coated positive electrode group 33, the double-sided coated negative electrode group 34, and the bipolar electrode group 36 each have a pair of base materials and a pair of electrolyte layers arranged so as to cover the electrode (positive electrode, negative electrode, or bipolar electrode), and further, the edges of the pair of electrolyte layers are adhered. Therefore, also in these battery members, the volatilization of the organic solvent from the electrode mixture layer is suppressed.

Example

[0203] Hereinafter, the present invention will be described more specifically by way of examples, but the present invention is not limited to these examples.

[0204] <Example 1> [Fabrication of the positive electrode active material layer] Li(Co 0.2 Ni 0.6 Mn 0.2 )O 2 (Positive electrode active material) 92 parts by mass, carbon black (conductive agent, trade name: Li400, average particle diameter 48 nm (manufacturer's catalog value), Denka Co., Ltd.) 4 parts by mass, polyvinylidene fluoride solution (binder, trade name: Kureha KF Polymer #1120, solid content: 12% by mass, Kureha Corporation) 33.3 parts by mass (of which the solid content is 4 parts by mass), and N-methyl-2-pyrrolidone (dispersion medium, NMP) 15 parts by mass were mixed to prepare a slurry. This slurry was applied onto a positive electrode current collector (aluminum foil with a thickness of 15 μm), dried at 120 °C, and then rolled to form a positive electrode active material layer with a single-sided coating amount of 200 g / m 2 , and a combined agent density of 2.8 g / cm 3 . Thus, a rectangular positive electrode laminate with a positive electrode active material layer formed on one surface of the positive electrode current collector was obtained.

[0205] [Fabrication of the negative electrode active material layer] Graphite (negative electrode active material) 98 parts by mass and CMC-SBR 2 parts by mass were mixed with pure water so as to be uniformly dispersed to prepare a slurry. This slurry was applied onto a negative electrode current collector (copper foil with a thickness of 10 μm), dried at 80 °C, and then rolled to form a negative electrode active material layer with a single-sided coating amount of 102 g / m 2 , and a combined agent density of 1.6 g / cm 3 . Thus, a rectangular negative electrode laminate with a negative electrode active material layer formed on one surface of the negative electrode current collector was obtained.

[0206] [Fabrication of the electrolyte layer] Lithium bis(fluorosulfonyl)imide (LiFSI) was used as an electrolyte salt, and the electrolyte salt was dissolved in an ionic liquid, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIFSI), at a concentration of 1.5 mol / L. 43 parts by mass of the ionic liquid in which the electrolyte salt was dissolved as described above and SiO 223 parts by mass of particles (trade name: AEROSIL OX50, Nippon Aerosil Co., Ltd.), 34 parts by mass of a binder (trade name: Kureha KF Polymer #8500, Kureha Corporation), and 143 parts by mass of NMP were mixed to prepare a slurry. This slurry was applied onto a substrate (made of polypropylene) and dried at 80 °C to form an electrolyte layer, thereby producing a rectangular electrolyte sheet with an electrolyte layer having a thickness of 20 μm formed on the substrate.

[0207] [Preparation of Electrolyte Composition] Vinylene carbonate (VC) was added as an additive at 0.8 wt% and lithium hexafluorophosphate (LiPF 6 ) was dissolved at 1.2 mol / L in an organic solvent prepared by mixing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) at a volume ratio of EC:EMC:DMC = 2:2:3 to prepare Solution A. To 95 parts by mass of this Solution A, 5 parts by mass of poly(methyl 3 - ethyloxetan - 3 - yl) methacrylate was added as Polymer A to prepare a sol - like electrolyte composition A.

[0208] [Fabrication of Battery Components] Two electrolyte sheets were prepared and laminated (transferred) onto the positive electrode laminate such that the positive electrode laminate was disposed between a pair of electrolyte layers. Similarly, the electrolyte sheets were laminated (transferred) onto the negative electrode laminate such that the negative electrode laminate was disposed between a pair of electrolyte layers. At this time, all four sides of the edges of the pair of rectangular electrolyte layers were laminated so as to protrude from the four sides of the edges of the positive electrode laminate or the negative electrode laminate. Then, using a table sealer, three sides of the edges of the pair of electrolyte layers were heat - sealed at 120 °C from above the substrate so that air did not enter, and the edges of the pair of electrolyte layers were adhered to each other.

[0209] Subsequently, a sol-like electrolyte solution composition A was poured into the remaining side of the electrolyte layer where the edges were not adhered, thereby forming a positive electrode mixture layer and a negative electrode mixture layer. Next, using a desktop sealer, the edges of the remaining side of the pair of electrolyte layers were heat-sealed from above the substrate so that air did not enter. As a result, all the edges of the electrolyte layers were adhered to each other.

[0210] The laminate in which the edges of the electrolyte layers were adhered was heated at 60 °C for 4 hours to gel the organic solvent with Polymer A, and a positive electrode member and a negative electrode member containing the gel-like electrolyte solution composition in the positive electrode mixture layer and the negative electrode mixture layer were obtained.

[0211] <Example 2> Positive electrode members and negative electrode members were produced in the same manner as in Example 1, except that the method for preparing the electrolyte solution composition in Example 1 was changed as follows. [Preparation of Electrolyte Solution Composition] To 95 parts by mass of the above Solution A, 5 parts by mass of pentaerythritol tetraacrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) was added as Polymer A, and 0.05 parts by mass of 2,2'-azobis(isobutyronitrile) (AIBN) (manufactured by Fujifilm Wako Pure Chemical Corporation) was further added to prepare a sol-like electrolyte solution composition B.

[0212] <Example 3> Positive electrode members and negative electrode members were produced in the same manner as in Example 1, except that the method for preparing the electrolyte solution composition in Example 1 was changed as follows. [Preparation of Electrolyte Solution Composition] An electrolyte solution composition C was prepared by using the above Solution A as it was.

[0213] <Comparative Example 1> Positive electrode members and negative electrode members without a substrate were produced in the same manner as in Example 3, except that the production of the battery members in Example 3 was changed as follows. [Production of Battery Members] A sol - like electrolyte composition C was poured into the positive electrode laminate and the negative electrode laminate to obtain a positive electrode mixture layer and a negative electrode mixture layer. The obtained positive electrode mixture layer and negative electrode mixture layer were superposed so that air did not enter. Finally, heating was carried out at 60 °C for 4 hours to obtain a battery member containing the sol - like electrolyte composition C in each of the positive electrode mixture layer and the negative electrode mixture layer.

[0214] [Volatility test] Regarding the positive electrode member and the negative electrode member (collectively referred to as the battery member) according to the examples and comparative examples, the volatility of the organic solvent before and after the production of the battery member was evaluated by comparing the mass after adding the electrolyte composition to the electrode laminate with the mass after heating at 60 °C for 4 hours to produce the battery member.

[0215] In the volatility test, the remaining amount of the organic solvent in the battery member was defined as follows. The results of the volatility test are shown in Table 1. Remaining amount (%)=(Mass of the battery member after heating / Mass of the battery member immediately after adding the electrolyte composition to the electrode laminate)×100

[0216] [Table 1]

[0217] [Storage test] The base material was peeled off from the positive electrode member according to Example 1 to produce a battery member without the base material (Comparative Example 2). Similarly, the base material was peeled off from the positive electrode member according to Example 2 to produce a battery member without the base material (Comparative Example 3). The difference due to the presence or absence of the base material was evaluated by measuring the change in the remaining amount of the organic solvent when these battery members were stored at room temperature for a long time.

[0218] In the storage test, the initial mass of the battery member was taken as the mass of the battery member immediately after production, and further, the mass of the battery member after leaving it at room temperature for t hours was measured. The remaining amount of the organic solvent was measured using the following formula. The larger the value of the remaining amount, the more the volatilization of the organic solvent from the battery member is suppressed, and it can be said that the change in the composition from the initial stage of the production of the battery member is small. The results of the evaluation for the positive electrode member are shown in Table 2, and the results of the evaluation for the negative electrode member are shown in Table 3. Residual amount after \(t\) hours (%) = (mass of the battery member after leaving it for \(t\) hours / mass of the battery member immediately after fabrication) × 100

[0219]

Table 2

[0220]

Table 3

[0221] As shown in Table 2 and Table 3, the battery members of Example 1 and Example 2 in which the base material was left at room temperature with the base material laminated had little weight loss even after long-term storage. On the other hand, the battery members of Comparative Example 2 and Comparative Example 3 in which the base material was peeled off had a significant mass reduction after storage. For example, in the positive electrode member of Example 1, the residual amount of the organic solvent after 72 hours was 95%, while in the positive electrode member of Comparative Example 2, the residual amount of the organic solvent after 30 minutes was significantly reduced to 51%.

[0222] From this result, it was found that the battery member with the base material laminated had a small change in composition from the initial stage of battery member fabrication even after a long time had passed since the electrode member was fabricated. That is, since this battery member can be stored for a long time before manufacturing a secondary battery even after applying an organic electrolyte solution in the manufacturing process, the yield of the battery member can be improved.

[0223] [Adhesion Strength Test] Using the above positive electrode member and negative electrode member, the adhesion strength between the electrode binder layer and the electrolyte layer was evaluated under the following conditions using a tensile testing machine (small bench-top testing machine FGS-TV, manufactured by Nidec-Shimpo Corporation) and a force gauge (FGP-0.2, manufactured by Nidec-Shimpo Corporation).

[0224] First, the battery members used in the adhesion strength test were cut out to a length of 50 mm (±5 to 10 mm). For the cut-out battery members, a part of a pair of base materials was peeled off and folded back at 90°, and the electrode mixture layer exposed at the upper part of the tensile tester was fixed using a chuck, and the electrolyte layer exposed at the lower part of the tensile tester was fixed using a chuck.

[0225] Next, the tensile tester was moved at a tensile speed of 50 mm / min to start the measurement. After the start of the measurement, the values of the central 30 mm excluding the measurement values of the first and last 10 mm were measured. As the measurement conditions, the sampling interval was about 10 times / second, the number of measurements was 2 times, and the average value was taken as the value of the adhesion strength. The adhesion strength was evaluated according to the following criteria, and the results are shown in Table 4. Adhesion strength of 0.07 N / cm or more... A Adhesion strength of 0.03 N / cm or more... B Adhesion strength less than 0.03 N / cm... C

[0226]

Table 4

[0227] As a result, as shown in Table 4, it was found that in the positive electrode member and the negative electrode member of Example 1 containing Polymer A, the adhesion between the positive electrode mixture layer and the electrolyte layer and the adhesion between the negative electrode mixture layer and the electrolyte layer were excellent.

[0228] [Fabrication of Test Secondary Battery] The base materials of the positive electrode member and the negative electrode member of Example 1 and Example 2 were peeled off, and after bonding the electrolyte layers of the positive electrode member and the negative electrode member together, they were punched out into a circle with a diameter of 16 mm. At this time, through the electrolyte layer, the positive electrode mixture layer and the negative electrode mixture layer were bonded so as to face each other. After placing this in a CR2032 type coin cell container, the upper part of the battery container was caulked through an insulating gasket to seal it, and a secondary battery was obtained (Example 1A, Example 2A).

[0229] [Evaluation of Battery Characteristics] Regarding the fabricated secondary battery, the battery characteristics at 25°C were measured under the following charge and discharge conditions using a charge and discharge device (manufactured by Toyo System Co., Ltd.).

[0230] (1) After performing constant current constant voltage (CCCV) charging at a termination voltage of 4.2 V and 0.1C, constant current (CC) discharge was carried out at 0.1C until the termination voltage reached 2.7 V. This charge and discharge process was repeated for 2 cycles to initialize the secondary battery. The termination condition for CCCV charging was either when the current value became 0.05C or less, or when 20 hours had elapsed. Here, C means "current value (A) / battery capacity (Ah)". The discharge capacity of the second cycle was taken as the discharge capacity at 0.1C. (2) Next, after performing constant current constant voltage (CCCV) charging at a termination voltage of 4.2 V and 0.1C, a cycle of constant current (CC) discharge at 0.5C until the termination voltage reached 2.7 V was carried out once, and the discharge capacity at 0.5C was determined. (3) Next, after performing constant current constant voltage (CCCV) charging at a termination voltage of 4.2 V and 0.1C, a cycle of constant current (CC) discharge at 2C until the termination voltage reached 2.7 V was carried out once, and the discharge capacity at 0.5C was determined.

[0231] Based on the obtained discharge capacity, the 0.1C discharge characteristics, 0.5C discharge characteristics, and 2C discharge characteristics were calculated according to the following formula. The results are shown in Table 5. The 0.1C discharge characteristics indicate that the larger the value, the higher the capacity that can be extracted from the battery at low currents. The 0.5C and 2C discharge characteristics indicate that the larger the value, the better the output characteristics of the battery. 0.1C discharge characteristics (%) = discharge capacity obtained in (1) / designed discharge capacity × 100 0.5C discharge characteristics (%) = discharge capacity obtained in (2) / designed discharge capacity × 100 2C discharge characteristics (%) = discharge capacity obtained in (3) / designed discharge capacity × 100

[0232] (4) Next, after performing constant current constant voltage (CCCV) charging at a termination voltage of 4.2 V and 0.1 C, a cycle of discharging at a constant current (CC) to a termination voltage of 2.7 V at 0.1 C was performed 100 times, and the discharge capacity at the 100-cycle point was determined. The capacity retention rate at the 100-cycle point was calculated based on the following formula. Capacity retention rate at the 100 - cycle point = Discharge capacity obtained in (4) / Discharge capacity obtained in (1)

[0233]

Table 5

[0234] The secondary batteries (Example 1A, Example 2A) fabricated using the battery members of Example 1 and Example 2, which have a pair of base materials and a pair of electrolyte layers, exhibited excellent discharge characteristics. This is presumably because the battery members of Example 1 and Example 2 include a base material and an electrolyte layer, thus suppressing the volatilization of the organic solvent. Furthermore, the secondary batteries according to Example 1A and Example 2A were also excellent in terms of capacity retention rate. This is presumably because in addition to the suppression of the volatilization of the organic solvent in the battery members of Example 1 and Example 2, the organic solvent was gelled by Polymer A, forming a good coating (SEI) on the electrode surface and improving the output characteristics of the secondary battery.

Explanation of Symbols

[0235] 1…Secondary battery, 6…Positive electrode group, 7…Negative electrode group, 8…Electrolyte layer, 8e…Edge of electrolyte layer, 9…Positive electrode, 10…Positive electrode current collector, 11…Positive electrode binder layer, 12…Negative electrode, 13…Negative electrode current collector, 14…Negative electrode binder layer, 15…Positive electrode member, 16…Base material, 17…Negative electrode member, 18…Current collector, 19…Electrode active material layer, 22…Electrode binder layer, 23…Electrode, 24…Electrolyte sheet, 26…Battery member.

Claims

1. A pair of base materials, A pair of electrolyte layers provided between the pair of base materials and having their edges adhered to each other, An electrode disposed between the pair of electrolyte layers, comprising: The electrode has a current collector and an electrode mixture layer provided on at least one surface of the current collector, The electrode mixture layer contains an electrode active material, an organic solvent, and an electrolyte salt, The electrolyte layer contains oxide particles and an ionic liquid, The battery member, wherein the electrode mixture layer contains at least one selected from the group consisting of a polymer containing pentaerythritol tetraacrylate as a monomer unit and a copolymer of methyl methacrylate and oxetanyl methacrylate.

2. The battery member according to claim 1, wherein the electrolyte layer contains a polymer and an electrolyte salt.

3. The battery member according to claim 1 or 2, wherein the organic solvent contains a carbonate ester.

4. The battery member according to any one of claims 1 to 3, wherein the pair of base materials covers the entire pair of electrolyte layers.

5. A pair of electrolyte layers having their edges adhered to each other, An electrode provided between the pair of electrolyte layers, comprising: The electrode has a current collector and an electrode mixture layer provided on at least one surface of the current collector, The electrode mixture layer contains an electrode active material, an organic solvent, and an electrolyte salt, The electrolyte layer contains oxide particles and an ionic liquid, The secondary battery, wherein the electrode mixture layer contains at least one selected from the group consisting of a polymer containing pentaerythritol tetraacrylate as a monomer unit and a copolymer of methyl methacrylate and oxetanyl methacrylate.

6. The secondary battery according to claim 5, wherein the electrolyte layer contains a polymer and an electrolyte salt.

7. The secondary battery according to claim 5 or 6, wherein the organic solvent contains a carbonate ester.

8. Step (a) of obtaining a laminate including a pair of base materials, a pair of electrolyte layers provided between the pair of base materials, and an electrode disposed between the pair of electrolyte layers; Step (b) of adhering the edges of the pair of electrolyte layers to each other, comprising: The electrode has a current collector and an electrode mixture layer provided on at least one surface of the current collector, The electrode mixture layer contains an electrode active material, an organic solvent, and an electrolyte salt, Step (a) is a step (x1) of disposing an electrode laminate including the current collector and an electrode active material layer provided on at least one surface of the current collector and containing the electrode active material between the pair of electrolyte layers. A method for manufacturing a battery member, comprising in this order: a step (x2) of forming the electrode binder layer by adding the composition containing the organic solvent and the electrolyte salt to the electrode active material layer to obtain the electrode.

9. The manufacturing method according to claim 8, wherein the electrode binder layer further contains a polymer capable of gelling the organic solvent.

10. The manufacturing method according to claim 9, further comprising a step (c) of gelling the organic solvent after the step (b).

11. The manufacturing method according to claim 8, wherein the composition further contains a polymerizable compound, and the polymerizable compound is a compound that becomes a polymer capable of gelling the organic solvent by polymerization.

12. The manufacturing method according to claim 11, further comprising a step (d) of polymerizing the polymerizable compound in the electrode binder layer after the step (b).

13. The manufacturing method according to any one of claims 8 to 12, wherein the electrolyte layer contains a polymer, oxide particles, and an electrolyte salt.

14. The manufacturing method according to any one of claims 8 to 13, wherein the organic solvent contains a carbonate ester.

15. The manufacturing method according to any one of claims 8 to 14, wherein the pair of base materials covers the entire pair of electrolyte layers.

16. The battery member according to any one of claims 1 to 4, wherein the electrode binder layer contains poly(3 - ethyloxetan - 3 - yl)methyl methacrylate or pentaerythritol tetraacrylate.

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