Method for manufacturing all-solid-state secondary batteries

Abstract

To provide a manufacturing method for an all-solid-state battery with improved discharge capacity and battery efficiency.SOLUTION: An all-solid-state secondary battery is formed by the steps of: bonding reduced graphene oxide to an oxide solid electrolyte; applying slurry containing an active material, the oxide solid electrolyte, and a binder onto the surface of a current collector to form a positive electrode active material layer and a negative electrode active material layer; forming a solid electrolyte layer on the positive electrode active material layer; forming the negative electrode active material layer on the solid electrolyte layer; and performing a thermal processing.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] One aspect of the present invention relates to an article, a method, or a manufacturing method. Alternatively, the present invention relates to a process, Pertaining to a machine, manufacture, or composition of matter. One embodiment of the present invention is a semiconductor device, a display device, a light-emitting device, a power storage device, a lighting device, or an electronic In particular, the present invention relates to electronic devices and their operating systems.

[0002] In this specification, the term "electronic device" refers to any device having a power storage device. An electro-optical device having a power storage device, an information terminal device having a power storage device, and the like are all electronic devices. [Background technology]

[0003] Electronic devices that are carried by users or worn by users have been actively developed.

[0004] Electronic devices carried by users or worn by users are examples of primary energy storage devices. It operates using batteries or secondary batteries as its power source. Electronic devices carried by users are designed to be used for long periods of time. It is desirable to use a large-capacity secondary battery for this purpose. If a battery is built in, the problem is that a large-capacity secondary battery is large and heavy. Progress is being made in developing small or thin, large-capacity secondary batteries that can be built into electronic devices.

[0005] Lithium ion batteries that use liquids such as organic solvents as a medium for transporting lithium ions Liquid secondary batteries are widely used. However, in secondary batteries that use liquid, Therefore, there are problems with the electrolyte decomposition reaction depending on the temperature range and potential used, and with the external There is a problem of leakage. In addition, secondary batteries that use liquid electrolytes have the risk of ignition due to leakage. Yes.

[0006] Fuel cells are a type of secondary battery that does not use liquids. They use precious metals for the electrodes and solid electrolyte materials. It is also an expensive device.

[0007] In addition, there is a type of secondary battery that does not use liquid, called a solid-state battery, which uses a solid electrolyte. For example, Patent Document 1 and Patent Document 2 are disclosed. 3. The electrolyte of the lithium-ion secondary battery is either a solvent, a gel, or a solid electrolyte. It is stated that it can be used.

[0008] In addition, an example in which graphene oxide is used in a positive electrode active material layer of a solid-state battery is described in Patent Document 4. There are. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2012-230889 A [Patent Document 2] JP 2012-023032 A [Patent Document 3] JP 2013-229308 A [Patent Document 4] JP 2013-229315 A Summary of the Invention [Problem to be solved by the invention]

[0010] In solid-state batteries, the interface between the inorganic solid electrolyte and the electrodes is in surface contact, so electrical resistance is high. It is difficult to obtain stable battery characteristics. One of the challenges is to reduce resistance.

[0011] In addition, the inorganic solid electrolytes in solid-state batteries are broadly classified into sulfide-based materials and oxide-based materials. Oxide-based materials, when containing titanium or germanium in their composition, have a high thermal conductivity compared to lithium metal. The low chemical stability of the inorganic solids in solid-state batteries leads to the reduction of titanium and germanium. A method for producing a solid-state battery with good productivity is provided by using an oxide-based material for the electrolyte.

[0012] Also provided is a configuration that increases the discharge capacity of an all-solid-state battery and improves the battery efficiency. [Means for solving the problem]

[0013] One problem with oxide-based solid-state batteries is that the electrolyte layer does not form sufficient paths between electrolyte particles. Its low ionic conductivity reduces charge / discharge capacity and makes high-rate charging difficult. Ionic conductivity can be improved by supplementing the path with sheet-like compounds.

[0014] In addition, an insulating electrolyte is mixed in to form an ion conduction path in the negative and positive electrode layers. Therefore, the electrical conductivity of the electrode is reduced. The improvement can be achieved by improving the conductivity of the electrolyte surface or by creating an electronic conduction path between active material particles. do.

[0015] The configuration disclosed in this specification is a current collector and a solid electrolyte, with the aim of improving the interface between the current collector and the solid electrolyte. A graphene compound is used to improve the bonding strength between the solid electrolyte and the surface of the material. By using this, the contact area is increased and the interface resistance between the current collector and the solid electrolyte is reduced, and therefore, It is possible to improve the battery efficiency and charge / discharge rate.

[0016] The solid electrolyte may be any electrolyte that can conduct lithium ions and contains a solid component. There is no particular limitation. For example, ceramics, polymer electrolytes, etc. can be mentioned. The electrolytes are broadly divided into polymer gel electrolytes, which contain an electrolyte solution, and polymer solid electrolytes, which do not contain an electrolyte solution. It can be done.

[0017] The configuration disclosed in this specification includes a positive electrode current collector, a negative electrode current collector, and a positive electrode current collector and a negative electrode current collector. The all-solid-state secondary battery has a solid electrolyte in contact with the graphene compound between them.

[0018] In the above-mentioned configuration, the graphene compound is reduced graphene oxide, and the reduced oxide The graphene oxide is characterized in that it covers at least a portion of the surface of the solid electrolyte.

[0019] In addition, a positive electrode current collector, a negative electrode current collector, and a solid electrolyte layer between the positive electrode current collector and the negative electrode current collector are provided. the solid electrolyte layer includes a graphene compound covering at least a portion of a surface of the solid electrolyte; The graphene compound has graphene oxide, and silicon is bonded to oxygen of the graphene oxide. At least a part of the surface of the graphene compound is preferably a silicon atom. The chemically modified compound is sometimes called surface-modified graphene. The present invention relates to a method for chemically modifying a graphene compound to change the function or properties of the graphene compound. In addition, it can also mean adding a functional group that has a specific function or property. The graphene oxide with functional groups can improve the volume resistivity and The electrical conductivity can be increased.

[0020] In the above configuration, a negative electrode active material layer is provided between the solid electrolyte layer and the negative electrode current collector. In this case, the negative electrode active material layer may contain reduced graphene oxide. The restored graphene oxide can increase the contact area between the solid electrolyte and the negative electrode active material. This can reduce the interface resistance.

[0021] In the above configuration, a positive electrode active material layer is provided between the solid electrolyte layer and the positive electrode current collector. In this case, the positive electrode active material layer may contain reduced graphene oxide. The restored graphene oxide can increase the contact area between the solid electrolyte and the positive electrode active material. This can reduce the interface resistance.

[0022] In each of the above configurations, a conductive assistant or A binder may be included. The conductive additive is acetylene black, ketjen black ( Carbon materials such as VGCF, graphite, etc. can be used. As the binder, polyvinylidene fluoride (PVDF) or the like can be used.

[0023] If a binder is not used, the solid-state secondary battery will be made up of a stack of particle aggregates. When a cross-section is observed, the interface between the positive electrode active material layer and the solid electrolyte layer may not be clear. The interface between the solid electrolyte layer and the negative electrode active material layer may not be clear. When the cathode is subjected to the discharging process, a mixed layer may be formed at the interface between the cathode active material layer and the solid electrolyte layer. do.

[0024] The solid electrolyte material of the positive electrode active material layer and the solid electrolyte material of the negative electrode active material layer may be the same, They may be different, but from the viewpoint of reducing material costs, they are preferably the same. If the electrolyte material is a solid electrolyte, smooth ion conduction is possible even if a mixed layer is formed at the interface. Effect of the Invention

[0025] According to one embodiment of the present invention, an all-solid-state lithium-ion secondary battery can be realized. By making the battery completely solid-state, it is possible to realize the elimination of the use of organic electrolyte, which can prevent leakage and the This can solve problems such as battery expansion due to evaporation of electrolyte.

[0026] In addition, all-solid-state batteries make it easier to create multiple layers within a single cell and to design multiple cells. All-solid-state batteries are characterized by low cycle degradation and high long-term reliability.

[0027] In addition, one or more protection circuits are provided for one or more storage devices, and A battery pack or a battery module is a battery pack or a battery module. Battery modules are not limited to electronic devices carried by users, but are also used in medical equipment, hybrid vehicles (HVs), etc. EV), electric vehicles (EV), plug-in hybrid vehicles (PHEV), and other next-generation It is also used in lean energy vehicles.

[0028] The description of these effects does not preclude the existence of other effects. An embodiment does not necessarily have to have all of these effects. Effects other than these may also be included. The above is self-evident from the description, drawings, claims, etc. Other effects can be extracted from the claims and other descriptions. [Brief description of the drawings]

[0029] [Figure 1] FIG. 1 is a cross-sectional view showing one embodiment of the present invention. [Diagram 2]1 is a cross-section of a measurement device for an all-solid-state battery. [Diagram 3] 1A and 1B are a perspective view and a cross-sectional view of an all-solid-state battery. [Figure 4] FIG. 1 is a perspective view of an all-solid-state battery. [Diagram 5] FIG. 1 is a diagram showing an example of a cross-sectional structure of an all-solid-state battery. [Figure 6] An example of a vehicle. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following description, and various modifications in form and details are possible by those skilled in the art. The present invention is not limited to the description of the following embodiments. It is not something that can be done.

[0031] (Embodiment 1) In this embodiment, a solid oxide electrolyte and a reduced graphite oxide on the surface of the solid oxide electrolyte are The positive electrode active material layer was fabricated by attaching phene to improve the ionic conductivity, and an all-solid-state secondary battery was fabricated. An example of how to fabricate a battery will be shown.

[0032] In this embodiment, the oxide solid electrolyte is a garnet-type lithium ion conductor LLZ. (Li 7 La 3 Zr 2 O 12 ) is used. This material, called LLZ, is a cubic crystal. Even if LLZ contains aluminum, zirconium, niobium, tantalum, etc. good.

[0033] Reduced graphene oxide (RGO) is then attached to the surface of the LLZ. The RGO content is 1wt% or more and 10wt% or less. The material is made into a slurry using a binder, which is then applied to the positive electrode current collector and dried to form the positive electrode active material. After drying, the material may be fired or pressed. Heating may also be performed.

[0034] The compound obtained by reducing graphene oxide is called "RGO (Reduced Graphene Oxide)." RGO is sometimes called "graphene oxide." Not all oxygen is eliminated, and some oxygen or atomic groups containing oxygen remain bonded. For example, RGO may have carbonyl groups such as epoxy groups, carboxyl groups, or In this specification and the like, the graphene compound may have a functional group such as a graph The graphene precursor may be a compound used to produce graphene. Graphene precursors include, for example, the above-mentioned graphene oxide and graphene oxide. Graphite and the like may be included. In addition, graphene containing an alkali metal and carbon such as oxygen may be included. Graphene having elements other than the element may be called a graphene analogue. The graphene compounds herein also include graphene analogues.

[0035] Next, a slurry containing a negative electrode active material, a solid electrolyte, and a binder is applied to the surface of the negative electrode current collector. The negative electrode active material layer is obtained by applying the coating and drying. After drying, the negative electrode active material layer can be obtained by performing a sintering or pressing process. Heating may be performed simultaneously during the pressing process. quality, oxide active material (Nb 2 O 5 , SiO), metal active materials (Al, In, Sn), etc. When forming a slurry composition, a non-polar solvent such as heptane can be used. The active material is dispersed using the dispersion medium.

[0036] The positive electrode current collector and the negative electrode current collector can be made of a known metal material that can be used for an all-solid-state battery. Possible, Cu, Ni, Al, V, Au, Pt, Mg, Fe, Ti, Cr, Zn, Ge, In The current collector contains one or more selected from the following:

[0037] Next, a solid electrolyte layer is formed on the positive electrode active material layer or the negative electrode active material layer. The negative electrode active material layer is placed on the electrolyte layer so as to be in contact with the electrolyte layer. Although it depends on the material of the solid electrolyte, it is 0.1 μm or more and 1 mm or less, preferably 1 μm or more and 100 μm or less.

[0038] At this stage, a solid electrolyte layer is formed on the positive electrode active material layer, a negative electrode active material layer is formed on the solid electrolyte layer, and A laminate is obtained in which the negative electrode current collector is stacked on the material layer in order. Then, heat treatment and pressing are performed to improve the density. You may go.

[0039] The obtained laminate is then housed in an exterior body such as a laminate film or a metal can. This makes it possible to fabricate an all-solid-state battery.

[0040] In this embodiment, reduced graphene oxide (RGO) is attached to the surface of the LLZ. However, the present invention is not limited to the above, and examples of the configuration of the all-solid-state battery are shown in Table 1. Corresponds to No.1.

[0041] [Table 1]

[0042] For example, as shown in No. 2 of Table 1, reduced graphene oxide ( RGO) may be attached.

[0043] In addition, as shown in No. 3 of Table 1, reduction was observed on both the surface of the positive electrode active material and the surface of the negative electrode active material. The battery may be an all-solid-state battery with modified graphene oxide (RGO) attached.

[0044] (Embodiment 2) In this embodiment, the surface of the positive electrode active material and / or the surface of the negative electrode active material are In an all-solid-state battery, reduced graphene oxide (RGO) is attached to the An example will be described in which a graphene compound having a functional group is attached to the surface of the solid electrolyte of the electrolyte layer.

[0045] Graphene compounds have excellent electrical properties, such as high electrical conductivity, as well as high flexibility and In addition, graphene may have excellent physical properties such as high mechanical strength. Depending on the type of modification, the compound may be able to have extremely low electrical conductivity and become an insulator. Graphene compounds enable surface contact with low contact resistance.

[0046] An example of graphene modified with an atom or atomic group is oxygen or an oxygen-containing functional group. The graphene or multigraphene modified with a group having an oxygen-containing functional group is also an example. Examples of the group include an epoxy group, a carbonyl group such as a carboxyl group, and a hydroxyl group. The graphene compound modified with oxygen or a functional group having oxygen is called an oxidized graphene compound. It is sometimes called laphene.

[0047] As an example of an ether-modified graphene compound, the structure represented by the following formula (200) is Examples of graphene compounds include those having the above structure.

[0048] [ka]

[0049] In formula (200), the GO layer on the particle is graphene or graphene oxide. R represents a substituted or unsubstituted chain having at least two ether bonds. represents a group.

[0050] In addition, an example of an ether-modified graphene compound is represented by the following formula (201): Examples of graphene compounds include those having the structure.

[0051] [ka]

[0052] In addition, in formula (201), the GO layer on the particle is graphene or graphene oxide. Represents Lafen.

[0053] In addition, we will explain the silylation of graphene oxide as an example of its modification. First, graphene oxide is placed in a container in a nitrogen atmosphere, and n-butyl ether is added to the container. Amino acid (C 4 H 9 NH 2 ) and keep at 60℃ and stir for 1 hour. Next, add Toluene to the container. Add alkyltrichlorosilane as a silylating agent and then immerse in a nitrogen atmosphere. The mixture was stirred at 60°C for 5 hours. Next, toluene was added to the container and the mixture was filtered by suction. A solid powder is obtained by dispersing it in ethanol. This is then filtered by suction to obtain a solid powder. The powder is obtained and dispersed in acetone. It is then filtered by suction to obtain a solid powder, which is then dissolved in water. The components are vaporized to obtain silylated graphene oxide.

[0054] The obtained graphene compound has a structure represented by the following formula (202).

[0055] [ka]

[0056] In formula (202), the GO layer on the particle is graphene or graphene oxide. Represents Lafen.

[0057] In the formula (202), R is a substituted or unsubstituted group having at least two ether bonds. R represents an unsubstituted chain group, and may be branched. The graphene compound is not limited to a single molecular weight or structure, but can be of any size. Therefore, the graphene compound according to one embodiment of the present invention can be used. It is not possible to specify the child structure in detail and fully express it. The chemically modified graphene compound according to the embodiment has at least two or more ether bonds. a graphene compound chemically modified with a silylating agent having a substituted or unsubstituted group; In some cases, it may be more practical to specify the product by expressing its manufacturing process, etc. In some cases, it may be impossible or impractical to avoid this. In some cases, the GO layer is fixed by two Si-O bonds, but the Si-O bonds are It may be fixed by one or three bonds. The bond is not limited to Si-O bonds. The GO and Si may be fixed by other bonds instead of the above.

[0058] In addition, an example of an ester-modified graphene compound is represented by the following formula (203): Examples of graphene compounds include those having the structure.

[0059] [ka]

[0060] In addition, an example of an ether-modified or ester-modified graphene compound is a compound represented by the following formula (2 04) is a graphene compound having a structure represented by the formula:

[0061] [ka]

[0062] In addition, whether or not a compound has been chemically modified can be determined by FT-IR analysis to determine whether or not the compound has an ether bond. For example, the measurement can be performed using Thermo ATR was performed using the Nicolet NEXUS 670 manufactured by SCIENTIFIC. To determine the degree of reflectance, an FT-IR analysis using the attenuated total reflectance method can be performed.

[0063] In addition, silylation was shown as an example of modification of graphene oxide. The modification is not limited to graphene oxide, but can also be applied to non-oxidized graphene. In addition, the modification described in this embodiment can also be used for graphene oxide. The present invention is not limited to the modification of graphene, but may be applicable to a wide range of graphene compounds. In addition, the modification is not limited to silylation, and the silylation is not limited to the above-mentioned method.

[0064] Modification is not limited to the introduction of one type of atom or atomic group, but rather involves the application of multiple types of modifications to produce multiple compounds. The modification may introduce several kinds of atoms or atomic groups. Also, the modification may include hydrogen, halogen atoms, carbon atoms, etc. The reaction may be a reaction to add a hydride group, an aromatic hydrocarbon group, or a heterocyclic compound group. Reactions that introduce atomic groups into aryl groups include addition reactions and substitution reactions. Friedel-Crafts reaction, Bingel reaction, etc. A radical addition reaction may be carried out on graphene, and a cycloaddition reaction may be carried out. A ring may be formed between the graphene and the atomic group by

[0065] By introducing specific atomic groups into graphene compounds, the physical properties of the graphene compounds can be changed. Therefore, by modifying the graphene compound according to the intended use, This makes it possible to intentionally impart desired properties to the graphene compound.

[0066] The configuration of an all-solid-state battery using a chemically modified graphene compound is shown in Table 2 below.

[0067] [Table 2]

[0068] This embodiment mode can be freely combined with the first embodiment mode.

[0069] (Embodiment 3) FIG. 1(A) is a diagram showing the concept of a solid-state battery, in which a solid electrolyte layer 8 is disposed between a positive electrode 81 and a negative electrode 82. 3. In addition, there are thin-film type all-solid-state batteries and bulk type all-solid-state batteries. All-solid-state batteries are all-solid-state batteries obtained by laminating thin films, and bulk-type all-solid-state The battery is an all-solid-state battery obtained by layering fine particles.

[0070] FIG. 1B is an example of a bulk-type all-solid-state battery, in which particulate positive electrode active material is disposed near a positive electrode 81. 87, and particulate negative electrode active material 88 in the vicinity of the negative electrode 82, so as to fill the gap between them. A solid electrolyte layer 83 is disposed between the positive electrode 81 and the negative electrode 82. A gap is formed between the positive electrode 81 and the negative electrode 82 by applying pressure. The stacked structure of the all-solid-state battery is described in the embodiment. Nos. 1, 2, and 3 in Table 1 shown in Example 1, and Nos. 4, 5, 6, and 7 in Table 2 shown in Example 2 The composition shall be one of the following.

[0071] FIG. 1(C) is an example of a thin-film all-solid-state battery. Thin-film all-solid-state batteries are produced by a gas phase method (vacuum Vapor deposition, thermal spraying, pulsed laser deposition, ion plating, cold spray The film is formed by using a method such as deposition, aerosol deposition, or sputtering. After forming wiring electrodes 85 and 86 on the plate 84, the positive electrode 81 is formed on the wiring electrode 85. A solid electrolyte layer 83 is formed on the electrode 81, and a negative electrode 82 is formed on the solid electrolyte layer 83 and the wiring electrode 86. This is an example in which a lithium ion battery is manufactured by forming a ceramic substrate 84. Examples of the substrate include a plate, a glass substrate, a plastic substrate, and a metal substrate.

[0072] Figure 2 shows an example of a cell for evaluating materials for all-solid-state batteries.

[0073] FIG. 2(A) is a schematic cross-sectional view of the evaluation cell. The evaluation cell includes a lower member 61, an upper member 62, and The electrode is fixed by rotating the holding screw 63. The plate 53 is pressed to fix the evaluation material. The lower member 6 made of stainless steel Between the upper member 62 and the cap screw 63 are O-rings 65 and 66 for sealing. is provided.

[0074] The evaluation material is placed on the electrode plate 51 and surrounded by an insulating tube 52. The evaluation material is pressed by the gate 53. An enlarged perspective view of the evaluation material and its surroundings is shown in Figure 2 ( B).

[0075] As an example of the evaluation material, a laminate of a positive electrode layer 50a, a solid electrolyte layer 50b, and a negative electrode layer 50c is shown. The cross-sectional view is shown in Fig. 2(C). Note that the same points are shown in Figs. 2(A), (B), and (C). The same symbols are used in places.

[0076] In addition, the electrode plates 51 and 53 are electrically connected to the current collector terminal screws, respectively, It is possible to measure electrical resistance, etc. by applying pressure to the material.

[0077] In addition, it is preferable to use a package with excellent airtightness as a sealing container for the solid-state battery. Ceramic or resin packages are used. When sealing, the outside air is blocked. It is preferable to carry out the reaction in a sealed atmosphere, for example, in a glove box.

[0078] FIG. 3(A) shows an all-solid-state secondary battery having external electrodes 71 and 72 and sealed in a package member. 1 shows a perspective view of a pond.

[0079] FIG. 3(B) shows an example of a cross section cut along the dotted line in FIG. 3(A). A package member 70a provided with an electrode layer 73a, a frame-shaped package member 70b, and a flat plate The electrode layer 73b is provided on the package member 70c, and the package member 70c is surrounded and sealed. The package members 70a, 70b, and 70c are made of an insulating material, such as a resin material or a ceramic material. A check can be used.

[0080] The external electrode 71 is electrically connected to the positive electrode layer 50a via the electrode layer 73a and functions as a positive electrode. The external electrode 72 is electrically connected to the negative electrode layer 50c via the electrode layer 73b. , which functions as a negative electrode.

[0081] In FIG. 3B, a stack of a positive electrode layer 50a, a solid electrolyte layer 50b, and a negative electrode layer 50c is taken as one set. Although an example has been given, a plurality of sets may be stacked.

[0082] In addition, an example of manufacturing a laminated secondary battery, which is different from the packaging method shown in FIG. 4(A), (B), (C), and (D).

[0083] FIG. 4A shows an external view of a positive electrode 503 and a negative electrode 506. The positive electrode 503 is a positive electrode current collector 501. The positive electrode active material layer 502 is formed on the surface of the positive electrode current collector 501. The negative electrode 503 has a region where the positive electrode current collector 501 is partially exposed (hereinafter referred to as the tab region). 06 has a negative electrode current collector 504, and a negative electrode active material layer 505 is formed on the surface of the negative electrode current collector 504. In addition, the negative electrode 506 has a region where the negative electrode current collector 504 is partially exposed, that is, a tab region. The area and shape of the tab regions of the positive electrode and the negative electrode are not limited to the example shown in FIG. do not have.

[0084] First, the negative electrode 506, the solid electrolyte layer 507, and the positive electrode 503 are laminated. The negative electrode 506, the solid electrolyte layer 507, and the positive electrode 503 are shown. Next, the bonding of the tab regions of the positive electrode 503 and the bonding of the tabs of the positive electrode on the outermost surface are shown. The positive electrode lead electrode 510 is bonded to the substrate region. For example, ultrasonic welding or the like is used for the bonding. Similarly, the tab regions of the negative electrodes 506 are joined to each other, and the negative electrode is attached to the tab region of the outermost negative electrode. The lead electrode 511 is joined.

[0085] Next, the negative electrode 506, the solid electrolyte layer 507, and the positive electrode 503 are arranged on the exterior body 509. The electrolyte layer 507 is a material layer containing a solid component capable of conducting lithium ions (ceramics). For example, the solid electrolyte layer 507 may be made of ceramic powder or glass powder. The powder is slurried and molded into sheets. The definition of ceramic is any material that is made of oxide, whether metal or nonmetal. Glass is a material made of inorganic compounds such as carbides, nitrides, and borides. Glass is amorphous. It is defined as a material that exhibits a glass transition phenomenon, but when it is made into a microcrystalline material, it is called a ceramic glass. Since ceramic glass has crystallinity, it is confirmed by X-ray diffraction. As the solid electrolyte, an oxide solid electrolyte, a sulfide solid electrolyte, etc. can be used. In addition, the positive electrode active material layer 502 and the negative electrode active material layer 505 may also contain a solid electrolyte. The conductive additive may be any material having electronic conductivity. For example, carbon materials, metal materials, etc. can be used.

[0086] In addition, the oxide solid electrolyte used as the positive electrode active material is Li 3 PO 4 , Li 3 B O 3 , Li 4 SiO 4 , Li 4 GeO 4 , LiNbO3 , LiVO 2 , LiTiO 3 , L iZrO 3 In addition, a composite compound of these may be used, for example BaLi 3 BO 3 -Li 4 SiO 4 The surface of the solid electrolyte is At least a part of the substrate may be covered with a coating layer having a thickness of 1 nm or more and 20 nm or less. The material used is a Li-ion conductive oxide.

[0087] The oxide solid electrolyte used as the negative electrode active material is Nb 2 O 5 , Li 4 Ti 5 O 1 2 In this specification, SiO is, for example, silicon monoxide. Or SiO refers to SiO 2 This refers to materials that have a higher silicon content than SiO x Here, it is preferable that x has a value close to 1. For example, x is preferably 0.2 or more and 1.5 or less, and more preferably 0.3 or more and 1.2 or less.

[0088] In addition, the sulfide solid electrolyte used as the positive electrode active material includes a material containing Li and S, Specifically, Li 7 P 3 S 11 , Li 2 S-SiS 2 , Li 2 SP 2 S 5 Examples include: This can be done.

[0089] Next, as shown in FIG. 4(C), the exterior body 509 is folded at the portion indicated by the dashed line. The outer periphery of the exterior body 509 is bonded. The exterior body 509 is a laminate of a metal foil and an organic resin film. A laminate film made of aluminum foil or stainless steel foil is used, and the bonding is performed using e.g. For example, thermocompression bonding or the like may be used. In this way, a laminate type secondary cell shown in FIG. A pond 500 can be created. In this example, a single laminate film is used for bonding. However, it is also possible to use a structure in which two laminate films are stacked and the edges are bonded to seal the film. It may also be composed of.

[0090] A plurality of laminated secondary batteries 500 are assembled into one battery module for use in electric vehicles, etc. It can be mounted on any

[0091] FIG. 5(A) shows three laminated secondary batteries 500 attached to a first plate 521 and a second plate 522. 5B is a perspective view showing how the plate 524 is sandwiched and fixed. The first plate 521 and the second plate 522 are fixed to each other using a fixing device 525a and a fixing device 525b. By fixing the distance between the secondary batteries 500 and 524, the three secondary batteries 500 can be pressurized.

[0092] 5(A) and 5(B) show an example in which three laminated secondary batteries 500 are used. However, the present invention is not particularly limited, and four or more secondary batteries 500 may be used. If there are more than 100 of them, they can be used as a power source for small vehicles, and if more than 100 are used, they can be used as a power source for large vehicles. It can also be used as a power source. It also has a protection circuit to prevent overcharging and a temperature rise monitor. A temperature sensor for monitoring the temperature may be provided in the laminated secondary battery 500. The shape is not limited to the laminate type, but may be a coin type, a cylindrical type, a square type, or the like.

[0093] In all-solid-state batteries, a certain amount of pressure is applied in the stacking direction of the stacked positive and negative electrodes. The contact state of the interface at the lamination portion can be kept good. By applying force, it is possible to suppress expansion in the stacking direction caused by charging and discharging of solid-state batteries. This makes it possible to improve the reliability of the all-solid-state battery.

[0094] (Embodiment 4) In this embodiment, an example in which an all-solid-state secondary battery according to one embodiment of the present invention is mounted on a vehicle will be described. Examples of vehicles include automobiles, motorcycles, bicycles, and the like.

[0095] When solid-state secondary batteries are installed in vehicles, hybrid vehicles (HEVs) and electric vehicles (EVs) can be used. or next-generation clean energy vehicles such as plug-in hybrid vehicles (PHEVs) It can be realized.

[0096] FIG. 6 illustrates a vehicle using an all-solid-state secondary battery according to one embodiment of the present invention. The automobile 8400 shown in A) is an electric automobile that uses an electric motor as a power source for running. Or, it is a vehicle that uses an electric motor and an engine as a power source for driving. The vehicle 8400 is a hybrid vehicle that can be used with all-solid-state secondary batteries. It has a power storage system. The all-solid-state secondary battery not only drives the electric motor 8406, Supplying power to light emitting devices such as headlights 8401 and room lights (not shown) In addition, if an abnormality occurs in the all-solid-state secondary battery, the power supply will be stopped and the hazard lights will not turn on. To avoid this, the vehicle is equipped with a secondary battery that is separate from the one used for driving. It is preferable.

[0097] In addition, all-solid-state secondary batteries are used in automobiles such as speedometers and tachometers. All-solid-state secondary batteries can also be used in automobiles, It can supply power to navigation systems and other devices installed in vehicles.

[0098] The automobile 8500 shown in FIG. 6(B) has a plug-in type all-solid-state secondary battery. Charging is performed by receiving power from an external charging facility using an in-vehicle method or a wireless power supply method. FIG. 6B shows a charging device 8021 mounted on a ground and a charging station 8022 mounted on a vehicle 8500. 8, an all-solid-state secondary battery 8024 is shown being charged via a cable 8022. When charging, please refer to CHAdeMO (registered trademark) or Combo for charging method and connector specifications. The charging device 8021 may be a charging station installed in a commercial facility. For example, plug-in technology can be used to The all-solid-state secondary battery 8024 mounted on the automobile 8500 is charged by an external power supply. Charging is done by converting AC power to DC power via a conversion device such as an ACDC converter. The all-solid-state secondary battery 8024 can be the same as that shown in the second embodiment. The battery has a secondary battery.

[0099] Although not shown, a power receiving device is mounted on the vehicle and receives power from a ground power transmitting device in a non-contact manner. In this case, the power transmission device is installed on the road or on the exterior wall. By incorporating this, charging can be done not only when the vehicle is stopped but also while the vehicle is moving. In addition, the vehicle exterior may be provided with a power supply. A solar cell may be provided in the vehicle to charge the all-solid-state secondary battery when the vehicle is stopped or running. For contactless power supply, an electromagnetic induction method or a magnetic field resonance method can be used.

[0100] FIG. 6C shows an example of a two-wheeled vehicle using the all-solid-state secondary battery of one embodiment of the present invention. The scooter 8600 shown in FIG. 6(C) includes an all-solid-state secondary battery 8602 and a side mirror 8601. The all-solid-state secondary battery 8602 supplies electricity to the turn signal light 8603. can be supplied.

[0101] In addition, the scooter 8600 shown in FIG. 6(C) has a solid-state secondary battery in the under-seat storage 8604. The all-solid-state secondary battery 8602 can be stored in the under-seat storage 8604. Even if it is of this type, it can be stored in the under-seat storage 8604.

[0102] This embodiment mode can be appropriately combined with the descriptions of other embodiment modes. [Explanation of symbols]

[0103] 50a Positive electrode layer 50b Solid electrolyte layer 50c negative electrode layer 51 Electrode Plate 52 Insulating tube 53 Electrode Plate 61 Lower member 62 Upper member 64 Wing nut 65 O-ring 66 O-ring 70a Packaging material 70b Packaging material 70c packaging material 71 External electrode 72 External electrode 73a Electrode layer 73b Electrode layer 81 Positive electrode 82 Negative electrode 83 Solid electrolyte layer 84 Substrate 85 Wiring electrode 86 Wiring electrode 87 Cathode active material 88 Anode active material 500 secondary battery 501 Positive electrode current collector 502 Positive electrode active material layer 503 Positive electrode 504 Negative electrode current collector 505 Negative electrode active material layer 506 negative electrode 507 Solid electrolyte layer 509 Exterior body 510 Positive lead electrode 511 Negative lead electrode 521 Plate 524 Plate 525a Fixtures 525b Fixtures 8021 Charging device 8022 Cable 8024 All-solid-state secondary battery 8400 Automobiles 8401 Headlight 8406 Electric Motor 8500 Automobiles 8600 Scooter 8601 Side mirror 8602 All-solid-state secondary battery 8603 Turn signal light 8604 Under-seat storage

Claims

1. A method for producing an all-solid-state secondary battery having a solid electrolyte layer between a positive electrode active material layer and a negative electrode active material layer, comprising the steps of: the solid electrolyte layer includes an oxide solid electrolyte which is an inorganic solid electrolyte, Attaching reduced graphene oxide to the oxide solid electrolyte; a first slurry including a positive electrode active material, the oxide solid electrolyte to which the reduced graphene oxide is attached, and a binder is applied to a surface of a positive electrode current collector to form the positive electrode active material layer; a second slurry including a negative electrode active material, the oxide solid electrolyte to which the reduced graphene oxide is attached, and a binder is applied to a surface of a negative electrode current collector to form the negative electrode active material layer; forming the solid electrolyte layer on the positive electrode active material layer; forming the negative electrode active material layer on the solid electrolyte layer; A method for manufacturing an all-solid-state secondary battery through a heat treatment process.

2. A method for producing an all-solid-state secondary battery having a solid electrolyte layer between a positive electrode active material layer and a negative electrode active material layer, comprising the steps of: the solid electrolyte layer includes an oxide solid electrolyte which is an inorganic solid electrolyte, a first slurry including a positive electrode active material, the oxide solid electrolyte to which the reduced graphene oxide is attached, and a binder is applied to a surface of a positive electrode current collector to form the positive electrode active material layer; a second slurry including a negative electrode active material, the oxide solid electrolyte to which the reduced graphene oxide is attached, and a binder is applied to a surface of a negative electrode current collector to form a negative electrode active material layer; A graphene compound having a functional group is attached to the oxide solid electrolyte to form the solid electrolyte layer; forming the solid electrolyte layer on the positive electrode active material layer; forming the negative electrode active material layer on the solid electrolyte layer; A method for manufacturing an all-solid-state secondary battery through a heat treatment process.

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