Secondary battery

Abstract

One aspect of the present invention provides: a lithium ion secondary battery which is lightweight and has a high capacity per weight; and a method for manufacturing the same. Instead of a metal, a resin material is used for an exterior body of a secondary battery. Sulfur or a sulfur compound is used as a positive electrode active material of the secondary battery. In addition, a solid electrolyte is used instead of an electrolyte in which lithium polysulfide dissolves. By employing the solid electrolyte, safety is enhanced due to the non-flammable nature thereof.

Description

secondary battery

[0001] One embodiment of the present invention relates to an object, a method, or a manufacturing method. Alternatively, the present invention relates to a process, a machine, a manufacture, or a composition of matter. One embodiment of the present invention relates to a power storage device including a secondary battery, a semiconductor device, a display device, a light-emitting device, a lighting device, an electronic device, or a manufacturing method thereof.

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

[0003] In this specification, the term "electricity storage device" refers to elements and devices in general that have an electricity storage function, including, for example, lithium ion secondary battery electricity storage devices (also called secondary batteries), lithium ion capacitors, and electric double layer capacitors.

[0004] In recent years, the development of various power storage devices, such as lithium-ion secondary batteries, lithium-ion capacitors, and air batteries, has been actively pursued. Demand for high-power, high-energy-density lithium-ion secondary batteries has been rapidly expanding in conjunction with the development of portable information terminals, such as mobile phones, smartphones, and notebook computers, portable music players, digital cameras, medical devices, next-generation clean-energy automobiles, such as hybrid vehicles (HVs), electric vehicles (EVs), and plug-in hybrid vehicles (PHVs), and the semiconductor industry. These batteries have become indispensable in the modern information society as a rechargeable energy source.

[0005] Furthermore, secondary batteries for portable information terminals or electric vehicles are desired to be lightweight and have a high capacity, i.e., a high capacity per unit weight. Among lithium-ion secondary batteries, secondary batteries using materials containing elemental sulfur as a positive electrode active material have attracted attention. Sulfur has a high theoretical capacity of approximately 1670 mAh / g, and is known to be a promising positive electrode active material in terms of energy density.

[0006] Furthermore, materials containing elemental sulfur are abundant resources, so they have the advantage of being cheaper than rare metals such as cobalt.

[0007] For example, research is being conducted on sulfur-based secondary batteries using sulfur and graphene sponge (3DGS) (Non-Patent Document 1).

[0008] Chao Lin et al. , “A facile synthesis of three dimensional graphene sponge composited with sulfur nanoparticles for flexible Li-S cathodes”, Phys. Chem. Chem. Phys. ,2016,18,22146-22153

[0009] In secondary batteries that use a material containing elemental sulfur as a positive electrode active material, lithium metal is used as an example of a negative electrode active material. During discharge, lithium metal dissolves in the electrolyte at the negative electrode to become ions, which react with sulfur at the positive electrode to be oxidized, resulting in the formation of an intermediate reaction product, lithium polysulfide (Li ２ S ｎ (2≦n≦8)) and then lithium sulfide (Li ２ S).

[0010] An object of one embodiment of the present invention is to provide a lithium-ion secondary battery having a high capacity per unit weight and a manufacturing method thereof.Another object of one embodiment of the present invention is to provide a lightweight lithium-ion secondary battery having a high total capacity and a manufacturing method thereof.

[0011] Another object of one embodiment of the present invention is to provide a lithium-ion secondary battery with excellent charge-discharge cycle characteristics and a manufacturing method thereof, or to provide a secondary battery with a long cycle life and a manufacturing method thereof.

[0012] Research is also underway on lithium-ion secondary batteries that use a gel-like electrolyte (polymer electrolyte) instead of a liquid electrolyte, or all-solid-state lithium-ion secondary batteries that use a solid electrolyte. Because the liquid electrolyte is conventionally used, metallic materials are used for the exterior to prevent leakage, and materials that are resistant to corrosion when in contact with the electrolyte or coatings that prevent reaction with the electrolyte are used inside the exterior. Using metallic materials for the exterior to enhance safety increases weight. In particular, for electric vehicles, the thickness of the metallic exterior is increased to protect against external impacts. Furthermore, the greater the number of secondary batteries installed in an electric vehicle, the greater the total weight, leading to increased energy consumption. For example, the weight of a secondary battery in a small electric vehicle is approximately 165 kg, while that in a medium-sized electric vehicle is approximately 250 kg.

[0013] Therefore, when a metal material is used for an exterior body of a secondary battery, safety and weight reduction are contradictory issues. An object of one embodiment of the present invention is to provide a lithium-ion secondary battery that achieves both safety and weight reduction.

[0014] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that problems other than these can be extracted from the description in the specification, drawings, and claims.

[0015] Instead of metal, the exterior of the secondary battery is made of a resin or ceramic material that acts as an insulating layer. Furthermore, a solid electrolyte is used instead of a liquid electrolyte, which dissolves lithium polysulfide. The use of a solid electrolyte improves safety because it is a non-flammable material.

[0016] The configuration of the invention disclosed in this specification is a secondary battery having a positive electrode active material layer and a solid electrolyte layer in contact with the positive electrode active material layer, the positive electrode active material layer and the solid electrolyte layer being surrounded by a casing made of a resin material, and the resin material containing an elastomer.

[0017] Furthermore, the secondary battery may have a positive electrode current collector and a negative electrode current collector, and the configuration includes a positive electrode current collector, a positive electrode active material layer in contact with the positive electrode current collector, a solid electrolyte layer in contact with the positive electrode active material layer, a negative electrode active material layer in contact with the solid electrolyte layer, and a negative electrode current collector in contact with the negative electrode active material layer, and the positive electrode current collector and the negative electrode current collector are surrounded by a case made of a resin material, and the resin material contains an elastomer.

[0018] In this specification, elastomer refers to a resin material with viscoelasticity. Elastomers include thermosetting elastomers, which do not soften when heated, and thermoplastic elastomers (TPEs), which soften when heated and return to a rubbery state when cooled. Rubber is a type of thermosetting elastomer, and vulcanized elastomers are generally called rubber.

[0019] In the above-described configuration, the positive electrode active material layer is a material layer in which sulfur or a sulfide (sulfur compound) and a carbon material are chemically or physically bonded to each other.

[0020] The positive electrode current collector or the negative electrode current collector having the above configuration can be made of a material having rubber elasticity instead of metal. A current collector made of a material having rubber elasticity is also called a rubber-like current collector. Rubber elasticity refers to the unique elasticity exhibited by materials such as rubber. Rubber elasticity is characterized by a high elastic limit (the stress at the limit at which the material will not return to its original shape after an external force is removed) and a low Young's modulus (0.1 MPa or more and 10 MPa or less). Materials having a network-like molecular structure in which chain molecules are crosslinked (also known as vulcanization) are known to exhibit rubber elasticity.

[0021] By using the solid electrolyte layer of the above configuration, a separator is not required, which leads to a reduction in the number of parts. Alternatively, a polymer electrolyte may be used in the electrolyte layer, resulting in a mixture of a solid electrolyte and a polymer electrolyte. Polymer electrolytes, which are low-molecular-weight or high-molecular-weight polymers, are preferred because they are flexible and therefore facilitate an increase in electrode density.

[0022] When forming the positive electrode active material layer, a resin material called a binder is used to bond the positive electrode active material particles to each other or to the current collector. The binder is also a low-molecular-weight or high-molecular-weight polymer, but it has insulating properties. The positive electrode active material particles and binder are mixed to form a paste for the positive electrode, which is then applied to the positive electrode current collector. The binder used for bonding has high insulating properties and does not contribute to the charging and discharging of lithium-ion secondary batteries.

[0023] As the material for the negative electrode active material layer, a material that absorbs or releases lithium can be used, and lithium metal, a lithium alloy, a carbon material, or a silicon material can be used.

[0024] Alternatively, a bipolar secondary battery may be used. A bipolar secondary battery has a structure in which a positive electrode active material layer is provided on one side of a current collector and a negative electrode active material layer is provided on the other side, and the internal resistance of the battery can be significantly reduced.

[0025] Furthermore, the exterior body (also called a housing or package member) of the secondary battery may be made of a resin material or a ceramic material and configured to surround the stack of positive or negative electrodes. For example, the stack of positive or negative electrodes may be wrapped in a thin polymer layer, or the stack of positive or negative electrodes may be encapsulated.

[0026] Furthermore, a film (ferrite or graphite) that acts as a radio wave absorber may be formed on the surface of the exterior body. By using a radio wave absorber, it is possible to realize a secondary battery that is difficult to detect on radar.

[0027] By using a solid electrolyte instead of an electrolytic solution and a resin material for the current collector, a lightweight and highly safe secondary battery can be realized.

[0028] Materials containing elemental sulfur are cheaper than rare metals such as cobalt, and can therefore significantly reduce the cost of electronic devices or electric vehicles.

[0029] FIG. 1 is a diagram illustrating an example of a cross-sectional structure illustrating one embodiment of the present invention. FIG. 2 is a diagram illustrating an example of a flow of a manufacturing process of a positive electrode active material. FIG. 3 is a diagram illustrating an example of an enlarged cross-sectional structure of a secondary battery illustrating one embodiment of the present invention. FIG. 4A is a diagram illustrating an example of a cross-sectional structure of a secondary battery illustrating one embodiment of the present invention, and FIG. 4B is a perspective view of the secondary battery. FIG. 5 is a diagram illustrating an example of a flow of a manufacturing process of a positive electrode active material layer. FIG. 6A is an example of a cross-sectional view of a stack illustrating one embodiment of the present invention, and FIG. 6B is an example of a cross-sectional view of a secondary battery. FIG. 7 is an example of a cross-sectional view of a secondary battery illustrating one embodiment of the present invention. FIGS. 8A and 8B are example perspective views of a secondary battery illustrating one embodiment of the present invention. FIGS. 9A to 9D are diagrams illustrating an example of an electronic device. FIGS. 10A to 10C are diagrams illustrating an example of an electronic device. FIGS. 11A to 11C are diagrams illustrating an example of a vehicle. FIGS. 12A and 12B are diagrams illustrating an example of an electric bicycle.

[0030] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be readily understood by those skilled in the art that various modifications can be made to the embodiments and details. Furthermore, the present invention should not be interpreted as being limited to the description of the embodiments shown below.

[0031] In this specification, the words "first" and "second" are used for the convenience of understanding the technical content or to identify each component. Therefore, the words "first" and "second" do not limit the number of each component. Furthermore, the words "first" and "second" do not limit the order of each component. Furthermore, the words "first" and "second" or identifying symbols used in this specification may not match the words or identifying symbols in the claims.

[0032] Embodiment 1 In this embodiment, an example of a secondary battery that is lightweight and has a high capacity per weight will be described with reference to Fig. 1. Fig. 1 shows an example of a schematic cross-sectional view of a secondary battery.

[0033] Figure 1 shows an example of a laminated structure of an all-solid-state battery that does not use metal electrodes and prioritizes weight reduction.

[0034] 1, the laminate constituting the secondary battery is surrounded by a package member 101 that serves as a housing. The laminate constituting the secondary battery is formed by sequentially stacking an anode current collector 106, an anode active material layer 105, a solid electrolyte layer 104, a cathode active material layer 103, and a cathode current collector 102.

[0035] In this embodiment, a rubber current collector is used as each of the positive electrode current collector 102 and the negative electrode current collector 106 .

[0036] The rubber-like current collector may be made of one or more rubber materials selected from the group consisting of styrene-butadiene rubber, styrene-isoprene-styrene rubber, acrylonitrile-butadiene rubber, butadiene rubber, ethylene-propylene-diene copolymer, butyl rubber, ethylene-propylene rubber, fluororubber, silicone rubber, and urethane rubber, and a particulate or fibrous conductive material (also called a conductive filler).

[0037] The physical properties of the rubber-like current collector may be, for example, tensile strength, elongation at break, and volume resistivity within the following ranges. The tensile strength is preferably 0.1 MPa to 30 MPa, more preferably 1 MPa to 20 MPa, and even more preferably 1 MPa to 10 MPa. The elongation at break is preferably greater than 100% to 300%, and even more preferably 130% to 200% (the length when no external force is applied is defined as 100%). The volume resistivity is preferably 0.1 Ω·m to 30 Ω·m, more preferably 0.1 Ω·m to 20 Ω·m, more preferably 0.1 Ω·m to 10 Ω·m, and even more preferably 0.1 Ω·m to 5 Ω·m.

[0038] The conductive material contained in the rubber-like current collector can be one or more of a conductive carbon material and a metal material such as aluminum, titanium, stainless steel, gold, platinum, zinc, iron, copper, etc. As the conductive carbon material, for example, one or more of the following can be used: carbon black such as acetylene black and furnace black; graphite such as artificial graphite and natural graphite; carbon fiber such as carbon nanofiber and carbon nanotube; graphene; and graphene compounds.

[0039] Examples of carbon fibers that can be used include mesophase pitch-based carbon fibers and isotropic pitch-based carbon fibers. Carbon nanofibers and carbon nanotubes can also be used as carbon fibers. Carbon nanotubes can be produced by vapor phase growth, for example.

[0040] When a rubber-like current collector is used as the positive electrode current collector, it may further contain an antioxidant such as a hindered phenol-based material.

[0041] The positive electrode active material layer 103 uses a mixed powder of sulfur powder and spherical particles. Specifically, spherical particles of phenolic resin are heated to carbonize at least the surface, and then mixed with sulfur to form a mixed powder, which is used as the positive electrode active material particles. It is preferable that the mixed powder contains spherical particles having a plurality of pores with a radius of 1 nm or less on the surface, and that the pores contain sulfur. The D50 of the spherical particles is preferably 5 μm or more and 10 μm or less.

[0042] D50 refers to the particle diameter at 50% of the calculated cumulative distribution of particles. Measurement of particle size is not limited to laser diffraction particle size distribution measurement, and the major axis of the particle cross section may be measured by analysis such as SEM or TEM (Transmission Electron Microscope). As a method for measuring D50 by analysis such as SEM or TEM, for example, 20 or more particles are measured, an accumulated particle amount curve is created, and the particle diameter when the accumulated amount accounts for 50% can be taken as D50.

[0043] The process for producing the positive electrode active material will now be described.

[0044] FIG. 2 shows an example of a flow of a process for producing a positive electrode active material.

[0045] First, spherical resin particles 301 are prepared and subjected to a first heating process for surface modification. The "spherical" shape of the spherical resin particles 301 refers to one or more shapes selected from a perfect sphere, an oval sphere, and a sphere with multiple recesses. The spherical resin particles 301 may also have protrusions or recesses on part of their surfaces. The shape of the spherical resin particles 301 can be observed using an electron microscope.

[0046] Although there is no particular limitation, a phenolic resin is used as the spherical resin particles 301. The spherical resin particles 301 are obtained by synthesizing a condensation reaction between phenols including polyhydric phenols and aldehydes, followed by separating and recovering the phenolic resin.

[0047] The spherical resin particles 301 are subjected to a first heating process for surface modification at a temperature between 500°C and 1000°C for a period between 2 hours and 10 hours. In this embodiment, the spherical resin particles 301 are subjected to a heat treatment at 650°C for 4 hours in a nitrogen atmosphere. The particles turn black after this heat treatment, indicating that at least a portion of the surface of the spherical resin particles 301 is carbonized. The first heating process causes atoms such as oxygen or hydrogen contained in the spherical resin particles 301 to be released, resulting in carbonization or the formation of pores. The resulting powder is referred to as spherical particles 302.

[0048] Sulfur 300 powder is prepared to mix the spherical particles 302 and sulfur powder 303. Commercially available sulfur 300 is crushed under an argon atmosphere and then sieved (with a mesh size of 53 μm) to prepare sulfur powder 303. High purity sulfur 300 is preferred, with a purity of 99.999% or higher. Mixing is performed using an agate mortar so that the weight ratio of sulfur 300 to the weight of spherical particles 302 is 30% to 50%.

[0049] Next, the spherical particles 302 and sulfur powder 303 are mixed. Thereafter, a second heating treatment is performed. For the second heating treatment, the powder is placed in an alumina boat, which serves as a container, and covered with aluminum foil. The lid is then placed in a tubular furnace, and the lid is kept closed. The lid is then placed in a tubular furnace, and the lid is kept closed while argon gas is flowing. The lid is kept closed at 150°C to 160°C for 3 hours to 20 hours. In this embodiment, the lid is kept closed at 155°C for 6 hours. Because sulfur evaporates easily, it is preferable to heat the powder in the container with the lid closed. The container is not limited to an alumina boat. The powder may be wrapped in aluminum foil under an argon atmosphere and placed in a sealable cylindrical metal container for heating.

[0050] The second heating causes the sulfur powder 303 and the spherical particles 302 to adhere to each other, forming a mass. This mass is then crushed and sieved (with a mesh size of 53 μm) to obtain a mixed powder 305. In the mixed powder 305, sulfur is held in the pores on the surfaces of the spherical particles 302.

[0051] The mixed powder 305 is obtained by the above steps, and can be mixed with a powder of a solid electrolyte to form a positive electrode active material layer.

[0052] An all-solid-state battery is fabricated using the mixed powder 305. Fig. 3 is an example of an enlarged cross-sectional structure of a laminate constituting the all-solid-state battery.

[0053] As shown in FIG. 3 , a secondary battery 400 of one embodiment of the present invention includes a positive electrode 410 , a solid electrolyte layer 104 , and a negative electrode 430 .

[0054] The positive electrode 410 includes a positive electrode current collector 102 and a positive electrode active material layer 103. The positive electrode active material layer 103 includes a positive electrode active material and a solid electrolyte 421. The positive electrode active material is the mixed powder 305 described above. The positive electrode active material layer 103 may also include a conductive material (also called a conductive additive) and a binder.

[0055] The solid electrolyte layer 104 has a solid electrolyte 421. The solid electrolyte layer 104 is located between the positive electrode 410 and the negative electrode 430, and is a region that does not have either the mixed powder 305 or the negative electrode active material 431. Note that in FIG. 3 , the solid electrolyte 421 of the solid electrolyte layer 104 and the solid electrolyte 421 of the positive electrode active material layer 103 are illustrated as being the same, but this is not particularly limited, and different solid electrolyte materials may be used.

[0056] The negative electrode 430 has a negative electrode current collector 433 and a negative electrode active material layer 105. The negative electrode active material layer 105 has a negative electrode active material 431 and a solid electrolyte 421. The negative electrode active material layer 105 may also have a conductive material and a binder. In addition, in FIG. 3 , the solid electrolyte 421 of the solid electrolyte layer 104 and the solid electrolyte 421 of the negative electrode active material layer 105 are illustrated as being the same, but this is not particularly limited, and different solid electrolyte materials may also be used.

[0057] For example, a sulfide-based solid electrolyte, an oxide-based solid electrolyte, or a halide-based solid electrolyte can be used as the solid electrolyte 421 contained in the positive electrode active material layer 103, the solid electrolyte layer 104, or the negative electrode active material layer 105. When the same material is used for the solid electrolyte 421 contained in the positive electrode active material layer 103, the solid electrolyte layer 104, or the negative electrode active material layer 105, there is an advantage in that the number of types of materials used can be reduced and the configuration can be simplified.

[0058] The sulfide-based solid electrolytes include thiolithium-based (Li １０ GeP ２ S １２ , Li ３．２５ Ge ０．２５ P ０．７５ S ４ ), sulfide glass (70Li ２ S・30P ２ S ５ , 30Li ２ S・26B ２ S ３ ・44LiI, 63Li ２ S・36SiS ２ ・1Li ３ P.O. ４ , 57Li ２ S・38SiS ２ ・5Li ４SiO ４ , 50Li ２ S・50GeS ２ ), sulfide crystallized glass (Li ７ P ３ S １１ , Li ３．２５ P ０．９５ S ４ Sulfide-based solid electrolytes have the advantages of being highly conductive, being able to be synthesized at low temperatures, and being relatively soft, which makes it easy to maintain conductive paths even after charging and discharging.

[0059] The oxide-based solid electrolyte includes a material having a perovskite crystal structure (La ２／３−ｘ Li ３ｘ TiO ３ ), a material having a NASICON type crystal structure (Li １−Ｙ Al Ｙ Ti ２−Ｙ (P.O. ４ ) ３ ), materials having a garnet-type crystal structure (Li ７ La ３ Zr ２ O １２ ), a material having a LISICON type crystal structure (Li １４ ZnGe ４ O １６ ), LLZO(Li ７ La ３ Zr ２ O １２ ), oxide glass (Li ３ P.O. ４ -Li ４ SiO ４ , 50Li ４ SiO ４ ・50Li ３ BO ３ ), oxide crystallized glass (Li １．０７ Al ０．６９ Ti １．４６ (P.O. ４ ) ３ , Li １．５ Al ０．５ Ge １．５ (P.O. ４ ) ３ Oxide-based solid electrolytes have the advantage of being stable in the atmosphere.

[0060] Halide-based solid electrolytes include LiAlCl ４ , Li ３ InBr ６ , LiF, LiCl, LiBr, and LiI. Furthermore, composite materials in which these halide-based solid electrolytes are filled into the pores of porous aluminum oxide or porous silica can also be used as solid electrolytes.

[0061] Also, different solid electrolytes may be mixed and used.

[0062] A carbon material or silicon can be used for the negative electrode active material layer 105. As the carbon material, graphite, graphitizable carbon (soft carbon), non-graphitizable carbon (hard carbon), carbon nanotubes, graphene, or carbon black may be used.

[0063] Examples of graphite include artificial graphite and natural graphite. Examples of artificial graphite include mesocarbon microbeads (MCMB), coke-based artificial graphite, and pitch-based artificial graphite. Here, spherical graphite having a spherical shape can be used as the artificial graphite. For example, MCMB may have a spherical shape and is preferred. Furthermore, it is relatively easy to reduce the surface area of ​​MCMB, and this may be preferred. Examples of natural graphite include flake graphite and spherical natural graphite.

[0064] In this embodiment, graphite and silicon particles are used as the negative electrode active material. Silicon particles are silicon powder used as the negative electrode active material for lithium-ion secondary batteries. Silicon particles refer to particles with an average particle size distribution, i.e., an average particle size of approximately 100 nm, and are sometimes referred to as nanosilicon particles. The silicon particles used are preferably prepared by pulverizing silicon raw materials to a uniform particle size. The silicon particles preferably contain at least one of silicon, silicon oxide, and silicon alloy. The weight ratio of graphite to silicon particles in the negative electrode active material layer is 9:1. The negative electrode active material layer preferably contains graphite in an amount at least nine times the weight of the silicon particles. A binder or conductive material is also added to form a slurry, which is then applied and dried. When a negative electrode active material layer containing a mixture of graphite and silicon particles is used as a negative electrode, charging and discharging are possible at -40°C or -30°C.

[0065] In the above configuration, the average particle diameter of the graphite particles mixed with the silicon particles is preferably 1 μm or more, and more preferably 5 μm or more and 30 μm or less. The particle size can be measured typically by laser diffraction particle size distribution measurement, but is not limited to laser diffraction particle size distribution measurement. The major axis of the particle cross section may also be measured by analysis using a SEM (scanning electron microscope) or a TEM (transmission electron microscope).

[0066] In this specification, the negative electrode active material contains at least both graphite particles and silicon particles. Since the silicon particles are mixed and used in the negative electrode, a secondary battery with high energy density can be realized.

[0067] When silicon particles absorb lithium ions, they expand, resulting in a volume expansion. Because there are gaps between adjacent graphite particles and silicon particles between the graphite particles, the expansion caused by the absorption of lithium ions has almost no effect on the negative electrode active material layer as a whole. The silicon particles exist in agglomerates between the graphite particles and in some of the gaps.

[0068] The weight ratio in this specification refers to the compounding ratio when preparing the electrode slurry described below, i.e., the weight ratio (wt%) of each active material and conductive material in the total weight (mixed powder). Therefore, it may not match the weight ratio of each active material and conductive material after the secondary battery is made.

[0069] Specifically, the weight ratio of silicon to the total weight of the powder material constituting the negative electrode active material is set to 7.5 wt % or more and 37.5 wt % or less. Another feature is that the weight ratio of graphite particles in the negative electrode active material layer is higher than the weight ratio of silicon particles.

[0070] Acetylene black (AB) may also be used as a type of conductive material. The acetylene black (AB) is attached or adsorbed to the surface of the graphite or the surface of the silicon particles, or chemically bonded to the surface of the graphite or the surface of the silicon particles.

[0071] Furthermore, a resin material may be mixed with the negative electrode active material. Since the resin binder is an insulator, it is preferable to use a small amount of resin material. In this specification, the resin material refers to a polymeric organic material with high insulating properties.

[0072] The exterior of the secondary battery 400 of one embodiment of the present invention can be made of various materials and in various shapes, and preferably has a function of applying pressure to the positive electrode, the solid electrolyte layer, and the negative electrode.

[0073] The secondary battery of one embodiment of the present invention preferably uses an airtight package for its exterior. For example, a ceramic package or a resin package can be used. Furthermore, the exterior is preferably sealed in a sealed atmosphere, such as in a glove box, while blocking external air.

[0074] Fig. 4A shows a cross-sectional view of a secondary battery using a package with excellent airtightness. Fig. 4B shows a perspective view of the secondary battery, and Fig. 4A corresponds to an example of a cross section taken along the dashed line.

[0075] The secondary battery in Fig. 4B is sealed in an exterior body having a plurality of package members. While Fig. 1 shows one example of package member 101, Fig. 4B uses three package members 770a, 770b, and 770c.

[0076] The laminate including the negative electrode active material layer 105, the solid electrolyte layer 104, and the positive electrode active material layer 103 is surrounded and sealed by a package member 770a having a flat plate with the negative electrode current collector 106 provided thereon, a frame-shaped package member 770b, and a package member 770c having a flat plate with the positive electrode current collector 102. The package members 770a, 770b, and 770c can be made of an insulating material, such as a resin material or ceramics.

[0077] The external electrode 771 is connected to the negative electrode active material layer 105 via the negative electrode current collector 106 and functions as an external terminal. The external electrode 772 is connected to the positive electrode active material layer 103 via the positive electrode current collector 102 and functions as an external terminal. The external terminals are connection terminals for connection and are not included in the secondary battery here. Therefore, the external electrodes 771 and 772 are not included in the secondary battery.

[0078] The positive electrode current collector 102 and the negative electrode current collector 106 are rubber current collectors. The secondary battery shown in FIGS. 4A and 4B is fabricated without using a metal material and uses sulfur as the positive electrode active material. This makes it possible to realize a lightweight secondary battery with a high capacity per weight.

[0079] In FIG. 1, the package member 101 and the laminate are in contact with each other, but this is not particularly limited, and there may be a gap between the laminate and the package member 101, and the gap may be filled with an inert gas or resin.

[0080] A laminate film without using metal foil may be used for the package member 101. The package member 101 may be made of an organic material that is lighter than a ceramic material.

[0081] (Embodiment 2) In Embodiment 1, an example of a secondary battery was shown in which powders were stacked and pressed to use a package with excellent airtightness. In the present embodiment, however, an example will be shown below in which a slurry is prepared using a binder or a solvent, and the slurry is applied to form a positive electrode active material layer in a sheet form.

[0082] FIG. 5 shows an example of a flow for preparing a slurry for forming a positive electrode active material layer on a positive electrode current collector.

[0083] The slurry refers to a mixture containing at least the positive electrode active material (mixed powder 305) and the solvent 908, and further containing one or more of the binder 907, the conductive material 906, and the solid electrolyte 421. The slurry is also called an electrode slurry or an active material slurry, and is sometimes called a positive electrode slurry when forming a positive electrode active material layer, and a negative electrode slurry when forming a negative electrode active material layer.

[0084] The binder 907 is also called a binding material. The binder 907 is a resin, and if a large amount of the binder 907 is contained, the ratio of the active material in the positive electrode decreases, and the discharge capacity of the secondary battery decreases. Therefore, the amount of the binder 907 mixed is kept to a minimum.

[0085] The conductive material 906 can be one or more selected from carbon, copper, tin, zinc, silver, and nickel. Carbon materials used for the conductive material 906 are typically carbon black (particulate carbon such as furnace black or acetylene black, graphite, etc.). In this embodiment, acetylene black (AB) is used as the conductive material 906.

[0086] As the binder 907, it is preferable to use a material such as polystyrene, polymethyl acrylate, polymethyl methacrylate (polymethyl methacrylate, PMMA), sodium polyacrylate, polyvinyl alcohol (PVA), polyethylene oxide (PEO), polypropylene oxide, polyimide, polyvinyl chloride, polytetrafluoroethylene, polyethylene, polypropylene, polyisobutylene, polyethylene terephthalate, nylon, polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN), ethylene propylene diene polymer, polyvinyl acetate, or nitrocellulose.

[0087] Furthermore, it is preferable to use a rubber material such as styrene-butadiene rubber (SBR), styrene-isoprene-styrene rubber, acrylonitrile-butadiene rubber, butadiene rubber, or ethylene-propylene-diene copolymer as the binder 907. Furthermore, fluororubber can be used as the binder 907.

[0088] NMP (N-methylpyrrolidone) or acetone is used as the solvent 908. The viscosity of the slurry material can be adjusted appropriately by the amount of the solvent, the reaction temperature, or the reaction time.

[0089] A binder 907 is dissolved in a solvent 908 and mixed with a conductive material 906 to prepare a slurry. The viscosity of the slurry material is adjusted appropriately by adjusting the amount of the solvent 908 or 909, the reaction temperature, or the reaction time. For example, a solvent 909, NMP in this embodiment, is added to the mixture in a thick kneaded state, and kneading is performed. If necessary, degassing is performed.

[0090] The resulting slurry is applied to a positive electrode current collector, which is made of carbon-coated aluminum foil.

[0091] Next, drying is carried out under reduced pressure. Drying to evaporate the solvent can be carried out by ventilation drying or reduced pressure (vacuum) drying. Drying is carried out at a temperature of 50°C or higher and lower than 120°C. Pressing may be carried out if necessary.

[0092] Through the above steps, a positive electrode 201 can be obtained in which a positive electrode active material layer is laminated on a positive electrode current collector.

[0093] Therefore, when forming the stacked structure shown in FIG. 1 , a positive electrode having a positive electrode active material layer 103 formed on a positive electrode current collector 102 in advance can be used, and the solid electrolyte layer 104 and the positive electrode active material layer 103 can be stacked so as to be in contact with each other.

[0094] This embodiment mode can be freely combined with other embodiment modes.

[0095] Embodiment 3 In this embodiment, an example in which lithium metal is used as a negative electrode current collector or a negative electrode active material layer of a secondary battery will be described. When lithium metal is used, the manufacturing process can be shortened.

[0096] 6A shows an example of a laminate, in which a secondary battery can be fabricated by forming a solid electrolyte layer 104 on lithium metal 107, placing a mixed powder thereon, and applying pressure. The mixed powder is a positive electrode active material layer 103, and is the mixed powder in which sulfur is held in pores on the surfaces of spherical particles, as shown in Embodiment 1. In addition to the mixed powder, a binder, a conductive material, or a solid electrolyte may be mixed into the positive electrode active material layer 103.

[0097] 6B shows an example in which external electrodes 773 and 774 are provided to enhance the practicality of secondary battery 490. A laminated structure is formed in which lithium metal 107, solid electrolyte layer 104, and positive electrode active material layer 103 are sandwiched between external electrodes 773 and 774, which are conductive electrodes. Positive electrode active material layer 103 contains mixed powder 305 and solid electrolyte 421. Solid electrolyte layer 104 also contains solid electrolyte 421.

[0098] To simplify the manufacturing process, a film of lithium metal 107 may be formed in advance on the external electrode 774 by sputtering or vapor deposition.

[0099] The lithium metal 107 is lightweight, and by using a mixed powder in which sulfur is held in the pores on the surfaces of spherical particles as the positive electrode active material, a secondary battery 490 with a high capacity per weight can be realized.

[0100] The external electrodes 773 and 774 are not included in the secondary battery.

[0101] This embodiment mode can be freely combined with other embodiment modes.

[0102] The secondary battery obtained in this embodiment has the fewest number of layers constituting one laminate among the other embodiments, making it a lightweight secondary battery, but the number of laminates may be increased to increase the total capacity. The secondary battery obtained in this embodiment can easily increase the total capacity by increasing the number of laminates.

[0103] In this embodiment, lithium metal is used as a negative electrode current collector or a negative electrode active material layer of a secondary battery, and aluminum foil is used as a positive electrode current collector of the secondary battery. When aluminum foil is used, the manufacturing process can be shortened.

[0104] FIG. 7 shows an example of the cross-sectional structure of a secondary battery.

[0105] The positive electrode active material layer 103 can be formed over the aluminum foil 109 using the manufacturing flow described in Embodiment 2.

[0106] The positive electrode active material layer 103 is the mixed powder in which sulfur is held in pores on the surfaces of spherical particles, as described in Embodiment 1.

[0107] The stack shown in FIG. 7 is obtained by providing a solid electrolyte layer 104 between a positive electrode active material layer 103 formed on an aluminum foil 109 and lithium metal 107 .

[0108] In addition, in order to increase the total capacity, a plurality of laminates can be stacked. When a plurality of laminates are stacked, a secondary battery can be manufactured with ease of handling by using a sheet-like laminate in which the positive electrode active material layer 103 is formed on the aluminum foil 109 by the method described in Embodiment 2.

[0109] The lithium metal 107 and the aluminum foil 109 are lightweight, and a secondary battery with a high capacity per weight can be realized by using a mixed powder in which sulfur is held in the pores on the surface of spherical particles as the positive electrode active material.

[0110] 7, the package member 101 may be enclosed in the same manner as in the first embodiment. The package member 101 may be made of a resin material or a ceramic material. Alternatively, the package member 101 may be made of a laminate film using aluminum foil. The thickness of the laminate film is about 100 μm, making the package member 101 lightweight.

[0111] The laminate film is a sheet made of a flexible substrate, and the sheet uses a laminate having an adhesive layer (also called a heat seal layer) on one or both sides of a metal film. The adhesive layer uses a heat-sealable resin film containing polypropylene or polyethylene. In this embodiment, the sheet is a metal sheet (also called a laminate film) having a nylon resin on the surface of an aluminum foil and an acid-resistant polypropylene film and a polypropylene film laminate on the back of the aluminum foil.

[0112] It is possible to seal three sides by overlapping and folding one laminate film (sometimes called three-sided sealing), but there is no particular limitation, and a method may also be used in which two laminate films are used to seal the electrolyte by surrounding it with four sides of the laminate film (sometimes called four-sided sealing).

[0113] Furthermore, a laminate film without using aluminum foil can also be used as the package member 101 .

[0114] This embodiment mode can be freely combined with other embodiment modes.

[0115] Fifth Embodiment In this embodiment, an example in which a plurality of stacks are housed in one package will be described.

[0116] A secondary battery 913 shown in FIG. 8A has a laminated body 950 provided with a terminal 951 and a terminal 952 inside a housing 930 .

[0117] It is preferable to fabricate a so-called bipolar secondary battery in which a positive electrode active material layer is provided on one surface of a current collector and a negative electrode active material layer is provided on the other surface. A bipolar secondary battery can reduce the number of terminals used in the laminate. The secondary battery 913 shown in FIG. 8A is an example of a bipolar secondary battery.

[0118] The structure of the laminate 950 uses the structure of the laminate shown in any one of the first, third, and fourth embodiments.

[0119] The terminal 952 is in contact with the housing 930, and the terminal 951 is not in contact with the housing 930 due to the use of an insulating material. Note that in Fig. 8A, for convenience, the housing 930 is shown separated, but in reality, the laminate 950 is covered by the housing 930, and the terminals 951 and 952 extend outside the housing 930. The housing 930 can be made of a metal material (e.g., aluminum) or a resin material.

[0120] When an organic material is used for the housing 930 and a rubber-like current collector is used for the current collector, almost no metal is used, and therefore, shielding of the electric field by the secondary battery can be suppressed. Therefore, when the secondary battery of this embodiment is used in an electronic device that is wirelessly charged using an antenna, shielding of the electric field by the secondary battery is small, and therefore, wireless charging can be performed efficiently.

[0121] For example, an antenna for wireless charging may be provided on one surface of the housing 930 of the secondary battery 913 shown in Fig. 8A. When an antenna is provided, a circuit board having a charge / discharge circuit is provided between the antenna and the secondary battery 913, and they are connected to each other.

[0122] The antenna is not limited to a coil shape, and may be, for example, a wire or plate shape. Antennas such as planar antennas, aperture antennas, traveling wave antennas, EH antennas, magnetic field antennas, and dielectric antennas can also be used. Alternatively, the antenna may be a flat conductor. This flat conductor can function as one of the conductors for electric field coupling. In other words, the antenna may function as one of the two conductors of a capacitor. This allows power to be exchanged not only through electromagnetic fields and magnetic fields, but also through electric fields.

[0123] 8B, the housing 930 shown in Fig. 8A may be formed from a plurality of materials. For example, the secondary battery 913 shown in Fig. 7B has a housing 930a and a housing 930b bonded together, and a laminated body 950 is provided in the area surrounded by the housing 930a and the housing 930b.

[0124] The housing 930a can be made of an organic material, specifically an insulating material typified by an organic resin. By using an organic material, the weight can be reduced.

[0125] The housing 930b can be made of, for example, a metal material.

[0126] 8A or 930b shown in Fig. 8B, a film (ferrite or graphite) that serves as a radio wave absorber may be formed on the surface of the housing 930 or 930b. By using a radio wave absorber, the secondary battery 913 can be made less visible to radar.

[0127] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0128] Embodiment 6 In this embodiment, an example in which a secondary battery which is one embodiment of the present invention is mounted on an electronic device will be described with reference to FIGS. 9A to 10C.

[0129] 9A shows an example of a wearable device. Wearable devices use lightweight secondary batteries with high total capacity as their power source. Furthermore, in order to enhance splash-proof, water-resistant, or dust-proof performance when used at home or outdoors, there is a demand for wearable devices that can be charged wirelessly as well as via wired charging, with an exposed connector.

[0130] For example, a secondary battery according to one embodiment of the present invention can be mounted on an eyeglasses-type device 4000 as shown in FIG. 9A . The eyeglasses-type device 4000 includes a frame 4000a and a display unit 4000b. Mounting a secondary battery on the temples of the curved frame 4000a makes it possible to provide an eyeglasses-type device 4000 that is lightweight, has a good weight balance, and can be used for a long time. By including the secondary battery according to one embodiment of the present invention, a lightweight and highly safe configuration can be realized.

[0131] Furthermore, the secondary battery according to one embodiment of the present invention can be mounted on a headset device 4001. The headset device 4001 includes at least a microphone unit 4001a, a flexible pipe 4001b, and an earphone unit 4001c. A lightweight secondary battery with a high total capacity can be provided in the flexible pipe 4001b and / or the earphone unit 4001c. By including the secondary battery according to one embodiment of the present invention, a lightweight and highly safe configuration can be achieved.

[0132] Furthermore, the secondary battery of one embodiment of the present invention can be mounted on a device 4002 that can be directly attached to the body. A lightweight secondary battery 4002b with high capacity per weight can be provided in a thin housing 4002a of the device 4002. By including the secondary battery of one embodiment of the present invention, a lightweight and highly safe configuration can be realized.

[0133] Furthermore, the secondary battery according to one embodiment of the present invention can be mounted on a device 4003 that can be attached to clothing. A lightweight secondary battery 4003b with high capacity per weight can be provided in a thin housing 4003a of the device 4003. By including the secondary battery according to one embodiment of the present invention, a lightweight and highly safe configuration can be realized.

[0134] Furthermore, the secondary battery of one embodiment of the present invention can be mounted on the belt-type device 4006. The belt-type device 4006 includes a belt portion 4006a and a wireless power receiving portion 4006b, and a lightweight secondary battery with high capacity per weight can be mounted inside the belt portion 4006a. By including the secondary battery of one embodiment of the present invention, a lightweight and highly safe configuration can be realized.

[0135] Furthermore, the secondary battery of one embodiment of the present invention can be mounted on the wristwatch device 4005. The wristwatch device 4005 has a display portion 4005a and a belt portion 4005b, and a lightweight secondary battery with high capacity per weight can be provided on the display portion 4005a or the belt portion 4005b. By providing the secondary battery of one embodiment of the present invention, a highly safe configuration can be realized.

[0136] The display unit 4005a can display not only the time but also various other information such as incoming emails and phone calls.

[0137] Furthermore, since the wristwatch device 4005 is a wearable device that is worn directly on the wrist, it may be equipped with sensors that measure the user's pulse, blood pressure, etc. Data on the user's exercise volume and health can be accumulated to manage the user's health.

[0138] FIG. 9B shows a perspective view of the wristwatch-type device 4005 removed from the wrist.

[0139] 9C shows a side view of the display portion 4005. Fig. 9C shows a state in which a secondary battery 913 is built in. The secondary battery 913 is provided at a position overlapping with the display portion 4005a, and is small and lightweight.

[0140] 9D shows an example of a wireless earphone. Here, the wireless earphone is shown as having a pair of main bodies 4100a and 4100b, but this does not necessarily have to be a pair.

[0141] The main bodies 4100a and 4100b each have a driver unit 4101, an antenna 4102, and a secondary battery 4103. They may also have a display unit 4104. They also preferably have a substrate on which a circuit such as a wireless IC is mounted, a charging terminal, and the like. They may also have a microphone.

[0142] The case 4110 has a secondary battery 4111. It is preferable that the case 4110 also has a board on which circuits such as a wireless IC and a charge control IC are mounted, and a charging terminal. It may also have a display unit, buttons, and the like.

[0143] The main units 4100a and 4100b can wirelessly communicate with other electronic devices such as smartphones. This allows sound data and the like sent from other electronic devices to be played back on the main units 4100a and 4100b. If the main units 4100a and 4100b have microphones, the sound picked up by the microphones can be sent to the other electronic device, and the sound data after processing by the electronic device can be sent back to the main units 4100a and 4100b for playback. This allows the devices to be used as, for example, translation devices.

[0144] The secondary battery 4103 included in the main body 4100a can be charged from the secondary battery 4111 included in the case 4110. A coin-type secondary battery, a cylindrical secondary battery, or the like can be used as the secondary battery 4111 and the secondary battery 4103. The secondary battery obtained in Embodiment 1 is lightweight and has a high energy density, and using it as the secondary battery 4103 and the secondary battery 4111 can contribute to reducing the weight of the wireless earphone.

[0145] 10A shows an example of a cleaning robot. The cleaning robot 6300 includes a display unit 6302 arranged on the top surface of a housing 6301, a plurality of cameras 6303 arranged on the side surfaces, a brush 6304, an operation button 6305, a secondary battery 6306, various sensors, and the like. Although not shown, the cleaning robot 6300 is provided with tires, a suction port, and the like. The cleaning robot 6300 can move by itself, detect dust 6310, and suck up the dust from a suction port arranged on the bottom surface.

[0146] For example, the cleaning robot 6300 can analyze an image captured by the camera 6303 to determine whether or not there is an obstacle such as a wall, furniture, or a step. Furthermore, if an object that may become entangled in the brush 6304, such as a wire, is detected through image analysis, the cleaning robot 6300 can stop the rotation of the brush 6304. The cleaning robot 6300 includes a secondary battery 6306 according to one embodiment of the present invention and a semiconductor device or an electronic component therein. By using the secondary battery 6306 according to one embodiment of the present invention in the cleaning robot 6300, the total capacity of the secondary battery 6306 can be increased and the weight of the entire cleaning robot 6300 can be reduced, thereby enabling the cleaning robot 6300 to be an electronic device with a long operating time.

[0147] Fig. 10B shows an example of a robot. A robot 6400 shown in Fig. 10B includes a secondary battery 6409, an illuminance sensor 6401, a microphone 6402, an upper camera 6403, a speaker 6404, a display unit 6405, a lower camera 6406, an obstacle sensor 6407, a movement mechanism 6408, a computing device, etc.

[0148] The microphone 6402 has a function of detecting the user's speaking voice, environmental sounds, etc. The speaker 6404 has a function of emitting sound. The robot 6400 can communicate with the user using the microphone 6402 and the speaker 6404.

[0149] The display unit 6405 has a function of displaying various information. The robot 6400 can display information desired by the user on the display unit 6405. The display unit 6405 may be equipped with a touch panel. The display unit 6405 may also be a detachable information terminal, which can be installed in a fixed position on the robot 6400 to enable charging and data transfer.

[0150] The upper camera 6403 and the lower camera 6406 have the function of capturing images of the surroundings of the robot 6400. Furthermore, the obstacle sensor 6407 can detect the presence or absence of obstacles in the direction of travel when the robot 6400 moves forward using the movement mechanism 6408. The robot 6400 can recognize the surrounding environment and move safely using the upper camera 6403, the lower camera 6406, and the obstacle sensor 6407.

[0151] The robot 6400 includes a secondary battery 6409 according to one embodiment of the present invention and a semiconductor device or an electronic component inside the robot 6400. By using the secondary battery according to one embodiment of the present invention in the robot 6400, the weight of the entire robot 6400 can be reduced, and the robot 6400 can be an electronic device with a long operating time.

[0152] FIG. 10C shows an example of an air vehicle (also called an unmanned aerial vehicle or drone). The air vehicle 6500 shown in FIG. 10C has a body 6504 equipped with a propeller 6501, a camera 6502, a secondary battery 6503, and the like, and has the ability to fly autonomously. The air vehicle 6500 can be used for transporting luggage, photographing subjects from the sky, and spraying pesticides. The propeller 6501 has a microcomputer as a motor control circuit for the motor that rotates it. The motor is supplied with power from the secondary battery 6503. While the air vehicle in FIG. 10C has one propeller 6501, this is not limited thereto and may be a rotorcraft (multicopter) having two or more propellers. The secondary battery 6503 is the secondary battery described in Embodiment 5.

[0153] For example, when the flying object 6500 is used for photography, image data captured by the camera 6502 is stored in a semiconductor device having a memory element. The semiconductor device can analyze the image data and detect the presence or absence of obstacles during movement. When the flying object 6500 is remotely controlled, the flying object 6500 has a wireless receiving circuit and receives instructions from a ground-based user controller to control the flight direction, etc. Furthermore, plastic or paper is used for the airframe 6504, and a rubber electrode is used as the current collector for the secondary battery 6503 described in Embodiment 5, with almost no metal used. This allows for smooth wireless reception without blocking wireless signals. Furthermore, the flying object 6500 has the characteristic of being difficult to detect by radar that uses signals such as reflected waves because it transmits signals.

[0154] Furthermore, when the flying object 6500 is used for transportation, a film (ferrite or graphite) that acts as a radio wave absorber may be formed on objects having metal surfaces, such as the propeller 6501, the motor, and the cargo (including dangerous goods). By using a radio wave absorber, the flying object 6500 can be made less visible to radar.

[0155] In particular, the secondary battery of the first embodiment uses a rubber-like current collector as the current collector and an organic material for the exterior body or housing, making the secondary battery less visible to radar. The secondary batteries of other embodiments can also be made less visible to radar by forming a radio wave absorbing film (ferrite or graphite) on the surface of the exterior body or housing. The radio wave absorbing film has a thickness of 1 mm or less, and can be made by applying a magnetic paint made by mixing ferrite magnetic powder with a binder to the surface and drying it. Ni-Zn ferrite or Mn-Zn ferrite can be used as the ferrite.

[0156] Furthermore, when the flying object 6500 is used for transportation, it is difficult to maintain balance in the air if the weight of the cargo is heavy. Therefore, it is preferable that not only the components of the airframe 6504 but also the secondary battery be lightweight. The components of the airframe 6504 can be made of a lightweight material, specifically, a resin material, a composite material such as CFRP (Carbon Fiber Reinforced Plastics), or paper. The flying object 6500 includes a secondary battery 6503 according to one embodiment of the present invention inside the airframe 6504. By using a secondary battery according to one embodiment of the present invention in the flying object 6500, the secondary battery becomes lighter and the total capacity can be increased. This allows the flying object 6500 to be lightweight overall, resulting in a flying object 6500 with a long flight distance and flight time.

[0157] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0158] Embodiment 7 In this embodiment, an example in which a secondary battery of one embodiment of the present invention is mounted on a vehicle will be described.

[0159] When a secondary battery is installed in a vehicle, next-generation clean energy vehicles such as hybrid vehicles (HVs), electric vehicles (EVs), or plug-in hybrid vehicles (PHVs) can be realized.

[0160] FIG. 11 illustrates an example of a vehicle using a secondary battery according to one embodiment of the present invention. An automobile 8400 shown in FIG. 11A is an electric automobile using an electric motor as a power source for traveling. Alternatively, it is a hybrid automobile that can appropriately select and use an electric motor or an engine as a power source for traveling. By using one embodiment of the present invention, the weight of the secondary battery can be reduced, and a vehicle with a long cruising distance can be realized. Furthermore, the automobile 8400 includes a secondary battery 8402. For example, modules of the secondary battery 8402 can be arranged on the floor of the interior of the vehicle. The secondary battery 8402 not only drives the electric motor 8406 but also supplies power to light-emitting devices such as a headlight 8401 and a room light (not shown).

[0161] The secondary battery can also supply power to display devices such as a speedometer and a tachometer included in the automobile 8400. The secondary battery can also supply power to semiconductor devices such as a navigation system included in the automobile 8400.

[0162] The automobile 8500 shown in FIG. 11B can charge the secondary battery of the automobile 8500 by receiving power from an external charging facility using a plug-in method and / or a wireless power supply method. FIG. 11B shows a state in which a ground-mounted charging device 8021 charges a secondary battery 8024 mounted on the automobile 8500 via a cable 8022. The charging method and connector specifications are appropriately determined using a predetermined method such as CHAdeMO (registered trademark) or Combo. The charging device 8021 can use a charging station installed in a commercial facility or a household power source. For example, plug-in technology can be used to charge the secondary battery 8024 mounted on the automobile 8500 using external power supply. Charging can be performed by converting AC power to DC power using a conversion device such as an AC-DC converter.

[0163] Although not shown, a power receiving device can be mounted on a vehicle and power can be supplied contactlessly from a ground-based power transmitting device to charge the vehicle. In the case of this contactless power supply method, by incorporating a power transmitting device into the road and / or exterior wall, charging can be performed not only while the vehicle is stopped but also while the vehicle is moving. This contactless power supply method can also be used to transmit and receive power between vehicles. Furthermore, solar cells can be installed on the exterior of the vehicle to charge the secondary battery while the vehicle is stopped and / or moving. Electromagnetic induction and / or magnetic resonance methods can be used for such contactless power supply.

[0164] 11C is an example of a two-wheeled vehicle using the secondary battery of one embodiment of the present invention. A scooter 8600 shown in FIG. 11C includes a secondary battery 8602, a side mirror 8601, and a turn signal light 8603. The secondary battery 8602 can supply electricity to the turn signal light 8603.

[0165] 11C can store a secondary battery 8602 in under-seat storage 8604. Even if under-seat storage 8604 is small, secondary battery 8602 can be stored in under-seat storage 8604. Secondary battery 8602 is removable, and when charging, secondary battery 8602 can be carried indoors, charged, and stored before riding.

[0166] According to one aspect of the present invention, the secondary battery can be made lighter and the discharge capacity of the secondary battery can be increased. Therefore, the capacity per unit weight can be increased, allowing the secondary battery itself to be made smaller and lighter. Reducing the weight of the secondary battery itself contributes to reducing the weight of the vehicle, thereby improving the cruising range. Furthermore, the secondary battery mounted on the vehicle can also be used as a power supply source for purposes other than the vehicle. In this case, for example, it is possible to avoid using a commercial power source during peak power demand periods. Avoiding the use of a commercial power source during peak power demand periods can contribute to energy conservation and reduction of carbon dioxide emissions.

[0167] 12A is an example of an electric bicycle using the secondary battery of one embodiment of the present invention. The secondary battery of one embodiment of the present invention can be applied to an electric bicycle 8700 shown in FIG. 12A. The power storage device of one embodiment of the present invention includes, for example, a plurality of secondary batteries and a charge / discharge control unit.

[0168] The electric bicycle 8700 includes a power storage device 8702. The power storage device 8702 can supply electricity to a motor (electric unit) that assists the rider. The power storage device 8702 is portable and is shown removed from the bicycle in FIG. 12B, where it corresponds to a secondary battery unit. The power storage device 8702 also includes a plurality of built-in batteries 8701, and a display unit 8703 can display the remaining battery charge. The remaining charge is also displayed on the display unit 8703. The power storage device 8702 also includes a charge / discharge control unit 8704 that can control charging or detect abnormalities of the secondary battery. The charge / discharge control unit 8704 is connected to the positive and negative electrodes of the battery 8701. The electric vehicle main unit of the electric bicycle 8700 also includes an operation unit 8712 provided in the handle portion. The operation unit 8712 includes a display unit 8713, a power switch 8714, and a power storage device 8711.

[0169] In the secondary battery of one embodiment of the present invention, a material containing elemental sulfur is less expensive than rare metals such as cobalt, and therefore the cost of the electric bicycle 8700 can be significantly reduced.

[0170] This embodiment mode can be implemented in appropriate combination with other embodiment modes.

[0171] 101: packaging member, 102: positive electrode current collector, 103: material layer, 104: layer, 105: material layer, 106: negative electrode current collector, 107: lithium metal, 109: aluminum foil, 201: positive electrode, 300: sulfur, 301: spherical resin particles, 302: spherical particles, 303: sulfur powder, 305: mixed powder, 400: battery, 410: positive electrode, 430: negative electrode, 431: material, 433: negative electrode current collector, 490: battery, 770a: packaging member, 770b: packaging member, 770c: packaging member, 771: external electrode, 772: external electrode, 773: external electrode, 774: external electrode , 906: Electrical material, 907: Binder, 908: Solvent, 909: Solvent, 913: Battery, 930: Housing, 930a: Housing, 930b: Housing, 950: Laminate, 951: Terminal, 952: Terminal, 4000: Device, 4000a: Frame, 4000b: Display unit, 4001: Device, 4001a: Microphone unit, 4001b: Pipe, 4001c: Earphone unit, 4002: Device, 4002a: Housing, 4002b: Battery, 4003: Device, 4003a: Housing, 4003b: Battery, 4005: Device, 4005a: Display unit, 4005b: Belt unit, 4006 : device, 4006a: belt part, 4006b: wireless power receiving part, 4100a: main body, 4100b: main body, 4101: driver unit, 4102: antenna, 4103: battery, 4104: display part, 4110: case, 4111: battery, 6300: cleaning robot, 6301: housing, 6302: display part, 6303: camera, 6304: brush, 6305: operation button, 6306: battery, 6310: dust, 6400: robot, 6401: illuminance sensor, 6402: microphone, 6403: upper camera, 6404: speaker, 6405: display part, 6406: lower camera, 6407: sensor, 6408: moving mechanism, 6409: battery, 6500: flying object, 6501: propeller, 6502: camera, 6503: battery, 6504: airframe, 8021: charging device, 8022: cable, 8024: battery, 8401: headlight, 8402: battery, 8406: electric motor, 8600: scooter, 8601: side mirror, 8602: battery, 8604: storage, 8701: battery, 8702: power storage device, 8703: display unit, 8704: charge / discharge control unit, 8711: power storage device, 8712: operation unit, 8713: display unit,8714: power switch,

Claims

A positive electrode active material layer; a solid electrolyte layer in contact with the positive electrode active material layer, the positive electrode active material layer and the solid electrolyte layer are surrounded by a housing made of a resin material, The secondary battery, wherein the resin material contains an elastomer. 　 A positive electrode current collector; a positive electrode active material layer in contact with the positive electrode current collector; a solid electrolyte layer in contact with the positive electrode active material layer; a negative electrode active material layer in contact with the solid electrolyte layer; a negative electrode current collector in contact with the negative electrode active material layer, the positive electrode current collector and the negative electrode current collector are surrounded by a housing made of a resin material, The secondary battery, wherein the resin material contains an elastomer.

3. The secondary battery according to claim 2, wherein the positive electrode current collector is a rubber current collector.

3. The secondary battery according to claim 2, wherein the negative electrode current collector is a rubber current collector.

3. The secondary battery according to claim 1, wherein the positive electrode active material layer contains spherical particles having a plurality of pores on the surface thereof with a radius of 1 nm or less, and the pores contain sulfur.

3. The secondary battery according to claim 1, wherein the positive electrode active material contained in the positive electrode active material layer is sulfur or a sulfur compound.

3. The secondary battery according to claim 1, wherein a surface of the casing is covered with an electromagnetic wave absorber.

Images