JP6875091B2 - Manufacturing method of power storage equipment, power storage equipment and power storage equipment - Google Patents

Description

The present invention relates to a method for manufacturing an electric power storage device, an electric power storage device, and an electric power storage facility.

In recent years, power generation methods using natural energy have been actively used for environmental protection. However, many natural energies cannot generate electric power stably. Therefore, a large-scale power storage facility is used as a method for averaging and stably supplying the amount of power generated by natural energy.

Examples of large-scale power storage equipment include equipment conventionally used for peak shifts in power plants such as pumped storage power generation and compressed air storage. Devices that can be used in large-scale power storage facilities include lithium-ion batteries (hereinafter, also referred to as LIB), vanadium redox flow batteries (hereinafter, also referred to as VRFB), sodium-sulfur batteries (hereinafter, also referred to as SSB), and the like. These can also be used as a standby power supply in the event of a power failure or as an uninterruptible power supply in facilities such as medical facilities, semiconductor factories, and data centers that cause serious problems if the power supply becomes unstable. is there. Among them, as a power storage system using LIB, a power storage system in which a plurality of modules in which a plurality of cells are stored in a rack having earthquake resistance is installed (for example, Patent Document 1) is known. ..

Japanese Unexamined Patent Publication No. 2008-251352

However, it is difficult to secure land that meets the conditions for construction of pumped storage power plants and compressed air storages, and it is not easy to install them in terms of construction period and construction cost. In addition, it can be said that the power storage efficiency is not sufficient because of the loss when converting electric energy into physical energy. In addition, since VRFB requires a solution circulation pump (drive unit) and SSB requires a heat source for heating electrolytes, there is no energy conversion loss from the viewpoint of power storage efficiency, and moving parts and heat sources are required. It can be said that the LIB that does not have is particularly excellent.
In LIB, in general, in order to ensure the conductivity of the active material layer constituting the electrode, a binder is added to fix the active material powder on the current collector. If the active material layer is made too thick, it may cause the active material layer to peel off or fall off, so that the size of a single cell cannot be easily increased. Therefore, when the LIB is used as a large-scale power storage facility, as described in Patent Document 1, a method of collecting and using a large number of small LIBs is adopted, but for each cell, There is a problem that the potential variation and the management of charge / discharge are complicated. Furthermore, in the case of a storage battery facility in which a large number of small LIBs are assembled, a passage for maintenance and a space for laying wiring for connecting the cells are required, so that the storage can be performed per volume (per area). There was room for improvement in the amount of energy (power storage density).

The present invention has been made in view of the above problems, and an object of the present invention is to provide a power storage device having excellent power storage efficiency and power storage density, and a method for manufacturing the same.

The present inventors have arrived at the present invention as a result of diligent studies to solve the above problems.
That is, in the present invention, the power storage tank construction step of constructing the power storage tank, and the positive electrode active material layer, the separator layer, and the positive electrode active material layer containing the positive electrode active materials that are not bonded to each other in the power storage tank and the bonding to each other. It is a method of manufacturing a power storage device including a storage layer arrangement step of arranging a storage layer including one or more cell units in which negative electrode active material layers including negative electrode active materials that have not been arranged are arranged in this order. The cell unit is arranged in the storage layer arrangement step, comprising a step of directly arranging the positive electrode active material layer, the separator layer and the negative electrode active material layer in the power storage tank. A method for manufacturing a power storage device, characterized in that at least one of the electric capacities is 5 kWh or more; one or more cell units in which a positive electrode active material layer, a separator layer and a negative electrode active material layer are arranged in this order are provided. The storage layer is a power storage device in which the storage layer is stored in the power storage tank. The positive electrode active material layer contains a positive electrode active material that is not bonded to each other, and the negative electrode active material layer is bonded to each other. A power storage device containing an uncoated negative electrode active material, wherein at least one of the electric capacities of the cell unit is 5 kWh or more; a power storage device including one or more of the power storage devices is provided. Regarding the power storage equipment to be installed.

According to the method for manufacturing an energy storage device of the present invention, it is possible to provide an energy storage device having excellent power storage efficiency and power storage density.

FIG. 1A is a cross-sectional view schematically showing an example of the power storage device of the present invention, and FIG. 1B is a cross-sectional view schematically showing an example of a cell unit constituting the power storage device of the present invention. It is a figure. FIG. 2 is a cross-sectional view schematically showing another example of the power storage device of the present invention. 3 (a) and 3 (b) are schematic views schematically showing an example of a step of directly arranging the positive electrode active material layer in the power storage tank, which constitutes the method for manufacturing the power storage device of the present invention. is there. 4 (a) and 4 (b) are perspective cross-sectional views schematically showing an example of a step of directly arranging the separator layer in the power storage device, which constitutes the method for manufacturing the power storage device of the present invention. .. 5 (a) and 5 (b) are perspective cross-sectional views schematically showing an example of a step of directly arranging the negative electrode active material layer in the power storage device, which constitutes the method for manufacturing the power storage device of the present invention. Is. FIG. 6 is a perspective sectional view schematically showing an example of a storage layer arrangement process constituting the method for manufacturing the power storage device of the present invention. FIG. 7 is a perspective sectional view schematically showing another example of the storage layer arrangement process constituting the method for manufacturing the power storage device of the present invention.

Hereinafter, the present invention will be described in detail.
In the present specification, when the positive electrode active material layer contains the positive electrode active material that is not bound to each other, the positive electrode active materials constituting the positive electrode active material layer are connected to each other by a binder (also referred to as a binder). It means that the position of the positive electrode is not fixed, and that all the positive electrode active materials in the positive electrode active material layer are not bound to each other.
The positive electrode active material layer in a conventional lithium ion battery is manufactured by applying a slurry in which a positive electrode active material and a binder are dispersed in a solvent to the surface of a positive electrode current collector or the like, and heating and drying the mixture. The positive electrode active material layer is in a state of being solidified by a binder. At this time, the positive electrode active materials are bound to each other by a binder, and the positions of the positive electrode active materials are fixed to each other.
On the other hand, in the positive electrode active material layer constituting the power storage device of the present invention, the positive electrode active materials in the positive electrode active material layer are not bound to each other, and the positions of the positive electrode active materials are not fixed. Therefore, when the positive electrode active material layer is taken out from the lithium ion battery, the positive electrode active material contained in the positive electrode active material layer can be easily loosened by hand, and its state can be confirmed.
The fact that the negative electrode active material layer includes the negative electrode active material layer that is not bound to each other is the same as in the case of the positive electrode active material layer.

First, the power storage device of the present invention will be described.
The present invention is a power storage device in which a storage layer including one or more cell units in which a positive electrode active material layer, a separator layer, and a negative electrode active material layer are arranged in this order is stored in a power storage tank. The positive electrode active material layer contains a positive electrode active material that is not bound to each other, and the negative electrode active material layer contains a negative electrode active material that is not bound to each other. At least one is a power storage device characterized by having a power storage device of 5 kWh or more.

In the power storage device of the present invention, the active materials constituting the positive electrode active material layer and the negative electrode active material layer (the positive electrode active material and the negative electrode active material are collectively referred to as active materials) are not bound to each other. Even when the active material layer is thickened, the bond that fixes the active materials is not broken. When the binding between the bound active materials is broken, the active material layer is peeled off and the electrical contact is poor. Therefore, in the conventional lithium ion battery, the thickness of the active material layer is determined by the binder. The upper limit was the thickness (about 200 μm) capable of stabilizing the shape.
On the other hand, in the power storage device of the present invention, since the active materials constituting the positive electrode active material layer and the negative electrode active material layer are not bound to each other, the active material layer does not peel off or crack due to the breaking of the binding, and the conventional method The thickness of the active material layer can be made thicker than that.

Further, since the positive electrode active material layer and the negative electrode active material layer constituting the power storage device of the present invention do not need to bind the active material with a binder or the like, it is an indispensable process in the production of the conventional lithium ion battery. It is not necessary to go through the steps of applying the slurry containing the binder to the surface of the current collector and drying or firing it. Therefore, the power storage device (power storage of the present invention) is a method in which the raw material to be the positive electrode active material layer and the raw material to be the negative electrode active material are sequentially put into the power storage tank through the separator and laminated in layers. The cell unit in the device) can be manufactured. At this time, since a drying device or a firing device for drying and firing the slurry is not required, the limit size capable of producing the positive electrode active material layer and the negative electrode active material layer is the above-mentioned drying device, firing device, or the like. There are no restrictions. Therefore, it is possible to manufacture an active material layer having a larger plan view size than the conventional one.
From the above, the power storage device of the present invention is more than the active material layer constituting the conventional lithium ion battery because the positive electrode active material layer and the negative electrode active material layer each contain an active material that is not bound to each other. , The electric capacity of the cell unit can be increased, and the electric capacity of at least one cell unit can be 5 kWh or more.

In the power storage device of the present invention, at least one of the electric capacities of the cell units constituting the power storage device is 5 kWh or more. In the power storage facility using the conventional LIB, the electric capacity of the cell unit (also referred to as a cell) is about 200 to 300 Wh. Therefore, the cell unit constituting the power storage device of the present invention is the same as the conventional cell unit. In comparison, it has about 20 times the battery capacity. Therefore, the power storage facility installed by using the power storage device of the present invention can easily adjust the voltage and current between the cell units as compared with the conventional one. Furthermore, the amount of energy that can be stored per unit area (power storage density) can be increased by significantly reducing the space required for wiring connecting cell units, passages for maintenance, and the like.

The power storage device of the present invention will be described with reference to FIGS. 1 (a) and 1 (b).
FIG. 1A is a cross-sectional view schematically showing an example of the power storage device of the present invention, and FIG. 1B is a cross-sectional view schematically showing an example of a power storage layer constituting the power storage device of the present invention. It is a figure. Although FIGS. 1 (a) and 1 (b) describe a stack of storage layers in the vertical direction, when a plurality of storage layers are laminated in the power storage device of the present invention, storage is performed. The direction in which the layers are laminated is not limited to the vertical direction.

As shown in FIG. 1A, in the power storage device 1, a storage layer 40 having three cell units 20 is stored in the power storage tank 10, and the cell units 20 have a current collector layer 30. They are laminated in the vertical direction (the direction indicated by the double-headed arrow V in FIG. 1A).
And at least one of the electric capacities of the cell unit 20 is 5 kWh or more. At the bottom of the power storage tank 10, a high power unit 50 extending to the outside of the power storage tank 10 is provided, and the high power unit 50 and the current collector layer 30 are in contact with each other.

Subsequently, the cell unit constituting the power storage device of the present invention will be described.
As shown in FIG. 1B, in the cell unit 20, the positive electrode active material layer 21, the separator layer 22, and the negative electrode active material layer 23 are arranged in this order.
In the cell unit constituting the power storage device of the present invention, the positive electrode active material layer, the separator layer and the negative electrode active material layer are arranged in this order, and the power storage device of the present invention includes at least one of the above cell units. ing.
The positions of the positive electrode active material layer 21 and the negative electrode active material layer 23 may be reversed.
In the power storage device 1 shown in FIGS. 1A and 1B, the cell unit 20 is separated from each other by the separator layer 22 so that the positive electrode active material layer 21 and the negative electrode active material layer 23 do not come into contact with each other. However, if necessary, a sealing portion may be provided on the peripheral portions of the positive electrode active material layer 21 and the negative electrode active material layer 23. When the seal portion is provided, in the cross-sectional views as shown in FIGS. 1 (a) and 1 (b), the seal portions are arranged at both ends of the positive electrode active material layer and the negative electrode active material layer, and the current collector layer. It is desirable that both ends of the separator layer reach the sealing portion.

The electric capacity of at least one of the cell units constituting the power storage device of the present invention is 5 kWh or more. The electric capacity of other cell units is not particularly limited.
In the power storage device of the present invention, a power storage layer including one or more of the cell units is stored in the power storage tank.

The number of cell units constituting the power storage layer is not particularly limited as long as it is one or more. When the number of cell units is two or more, each cell unit may be connected in series or in parallel, and a switch mechanism is mounted so that series and parallel can be arbitrarily switched. You may.

In the present specification, the power storage layer is the smallest unit capable of controlling charge / discharge. For example, as shown in FIG. 1A, when three cell units 20 are connected in series, three cell units 20 form one storage layer 40. Further, if three cell units are connected in parallel and charging / discharging can be performed only when the three cell units are connected in parallel, the three cell units form one storage layer.
On the other hand, although three cell units are connected in parallel, if only one cell unit can be individually charged and discharged by a switch mechanism or the like, only the one cell unit can be used as a storage layer. Call.

In the power storage device of the present invention, the cell units may be laminated so that the positive electrode active material layer and the negative electrode active material layer face each other via the current collector layer. At this time, the positive electrode active material layer of one cell unit and the negative electrode active material layer of the other cell unit are electrically connected via the current collector layer. Further, when a plurality of cell units are laminated with each other via the current collector layer, the direction is preferably a vertical direction.

In the present specification, the current collector layer refers to a portion of the wiring for moving electricity in the power storage tank that is in direct contact with the positive electrode active material layer and / or the negative electrode active material layer, and refers to the positive electrode active material layer. The portion that is not in direct contact with either the material layer or the negative electrode active material layer is called a strong electric part.
The high-power section includes wiring for moving electricity in the power storage tank other than the current collector layer (wiring between cell units) and wiring for moving electricity between the inside and outside of the power storage tank (wiring between cell units). Wiring for supplying power from the power storage tank to the outside, etc.) is included.
The current collector layer and the current collector layer may be integrated, or the current collector layer and the current collector layer may be in contact with each other.
The material constituting the high-voltage part is not particularly limited, but it is desirable that the material is made of copper, aluminum, titanium, stainless steel, or nickel.

The inner surface of the power storage tank may be provided with an immersion-proof layer for preventing the permeation of the electrolytic solution. When the immersion-proof layer is provided on the inner surface of the power storage tank, it is possible to prevent the electrolytic solution from permeating into the material constituting the power storage tank.
The material constituting the immersion-proof layer may be a material that does not easily penetrate the electrolytic solution and has low electrical conductivity, and is a film made of an insulating resin (polyethylene, polypropylene, fluororesin, silicone resin, etc.) and the above-mentioned insulation. A laminate of a sex resin and a metal foil is preferable. Among them, a laminate of an insulating resin and a metal foil is more preferable, and examples of the laminate of the insulating resin and the metal foil include an aluminum laminate film formed by laminating a film made of the insulating resin and an aluminum foil.

In the power storage device of the present invention, it is desirable that a lid for sealing the power storage tank is provided on the upper part of the power storage tank.
If a lid for sealing the power storage tank is provided on the upper part of the power storage tank, it becomes easy to prevent foreign matter such as dust and dirt from entering from the outside of the power storage tank.
When the power storage device is provided with a lid, a pressure release valve, a vent, or the like for releasing the pressure inside the power storage tank may be provided in the power storage tank and / or the lid, if necessary.

In the power storage device of the present invention, it is desirable that the power storage tank and the lid are provided with a waterproof layer.
When the power storage tank and the lid are provided with a waterproof layer, it is possible to prevent moisture from entering the inside of the power storage tank, and the durability is improved.
The waterproof layer may be provided at any of the power storage tank and the lid, but it is desirable that the waterproof layer is provided inside the power storage tank (inner wall surface) and on the inner surface of the lid.
However, when an immersion-proof layer for preventing the permeation of the electrolytic solution is provided on the inner surface of the power storage tank, it is desirable to provide a waterproof layer on the outside of the immersion-proof layer.
When the waterproof layer is provided at the above-mentioned place, it is possible to prevent the moisture contained in the material constituting the power storage tank and the lid from entering the power storage tank.
Two or more waterproof layers may be provided.

In the power storage device of the present invention, a plurality of the storage layers are vertically laminated so that the cell unit faces the positive electrode active material layer and the negative electrode active material layer via the current collector layer. It is desirable to have.
In the power storage layer, when the positive electrode active material layer and the negative electrode active material layer are laminated so as to face each other via the current collector layer, a plurality of cell units are connected via the current collector layer. .. That is, the cell units are connected in series, and the voltage that can be taken out from the storage layer rises.
Further, when the cell units are laminated in the vertical direction, pressure is applied to the current collector layer due to the weight of the cell unit itself, so that the contact property of the cell unit with the current collector layer is improved and the internal resistance is reduced. It will be easier.

In the power storage device of the present invention, it is desirable that the power storage layer is pressurized downward in the vertical direction.
When the power storage layer is pressurized downward in the vertical direction, the contact property between the cell units is improved and the internal resistance can be reduced.
The method of pressurizing the storage layer downward in the vertical direction is not particularly limited, but for example, a heavy object such as a brick or a stone is placed on the uppermost part of the power storage tank (the lower side if there is a lid). Power is supplied by a method of pressurizing or by arranging a bag-shaped object capable of storing liquid at the top of the power storage device (below the lid, if any) and allowing the liquid to flow into the bag-shaped object. Examples include a method of applying a load based on the weight of the liquid from the top of the storage tank.
When the storage layer is pressurized with a heavy object, it is desirable to arrange a plate-like object between the storage layer and the heavy object so that the pressure of the heavy object is dispersed throughout the storage layer. When the storage layer is pressurized by flowing a liquid into the bag-shaped object, it is desirable that the liquid flowing into the bag-shaped object does not contain water.
The bag-shaped object may be divided into a plurality of pieces. For example, a plurality of pressure sensors are arranged on the surface of each cell unit or each storage layer so that the numerical value of each pressure sensor is in a preferable range. The degree of pressurization may be appropriately adjusted by changing the amount (weight) of the liquid flowing into each bag-shaped material.

In the power storage device of the present invention, the internal dimensions of the power storage tank follow the change in the horizontal area of the plurality of cell units, and the horizontal area of the one cell unit is vertically downward. A support plate that is larger than the horizontal area of the other cell units arranged on the side and has substantially the same area as the horizontal area of the one cell unit on the lower side in the vertical direction of the one cell unit. Is desirable.
This will be described with reference to FIG.

FIG. 2 is a cross-sectional view schematically showing another example of the power storage device of the present invention.
In the power storage device 2 shown in FIG. 2, the internal dimensions of the power storage tank 10 follow changes in the horizontal areas of the cell units 20a, 20b, and 20c stacked in the vertical direction, and are arranged on the upper side. The horizontal area of the cell unit 20a is larger than the horizontal area of the other cell units 20b arranged on the lower side in the vertical direction.
When the internal dimensions of the power storage device 10 follow the horizontal areas of the cell units 20a, 20b, and 20c, each cell unit is housed inside the power storage tank in just proportion, so that due to vibration or the like. It does not easily shift. When a support plate 31a having substantially the same area as the cell unit 20a is arranged on the lower side in the vertical direction of the cell unit 20a arranged on the upper side, the weight of the cell unit 20a is supported by the support plate 31a. Since the support plate 31a is supported by the power storage tank 10 arranged around the cell unit 20b, no load is applied to the cell unit 20b. The support plate 31a has conductivity and also functions as a current collector layer. Further, since the entire surface of the cell unit 20a is supported by the support plate 31a, it is possible to prevent the end portion of the cell unit 20a from hanging down or being deformed.
The relationship between the cell unit 20b and the support plate 31b is the same as the relationship between the cell unit 20a and the support plate 31a.

The support plate may or may not have conductivity. When the support plate has conductivity, the support plate also acts as a current collector layer, and therefore can be used as both a current collector layer and a support plate. When the support plate does not have conductivity, a current collector layer is formed on both sides of the support plate, and the current collector layers formed on both sides of the support plate are electrically connected to each other to form a current collector. Support plates can be placed between the layers.
The support plate may have enough rigidity to disperse the load of the cell unit arranged on the upper side to the cell unit arranged on the lower side without transmitting it to the power storage tank, and the material and thickness of the support plate may be sufficient. The size is not particularly limited.

It is desirable that at least one of the positive electrode active material and the negative electrode active material is a coating active material whose surface is partially or wholly covered with a coating layer containing a polymer compound.
The coating layer that coats the positive electrode active material is called the positive electrode coating layer, the coating layer that coats the negative electrode active material is called the negative electrode coating layer, and the positive electrode active material coated by the positive electrode coating layer is made of the coated positive electrode active material and the negative electrode coating layer. The coated negative electrode active material is also referred to as a coated negative electrode active material.

The positive electrode active material layer constituting the power storage device of the present invention will be described.
The positive electrode active material layer contains a positive electrode active material that is not bound to each other, and may contain a conductive auxiliary agent, if necessary.
That is, in the positive electrode active material layer constituting the power storage device of the present invention, the positive electrode active materials constituting the positive electrode active material layer are not bound to each other by a binder or the like.

The positive electrode active material may be the positive electrode active material itself, or may be a coated positive electrode active material in which a part or all of the surface of the positive electrode active material is coated with a positive electrode coating layer containing a polymer compound. However, it is desirable that it is a coated positive electrode active material.

The thickness of the positive electrode active material layer is not particularly limited, but is preferably 100 to 10,000 μm.

As the positive electrode active material constituting the positive electrode active material layer, conventionally known ones can be preferably used, and a compound capable of inserting and removing lithium ions by applying a certain potential, which is used as a counter electrode. A compound capable of inserting and removing lithium ions at a higher potential than that of the negative electrode active material can be used.

As the positive electrode active material, composite oxide of lithium and transition metal {composite oxide is a transition metal is one _{(LiCoO 2, LiNiO 2, LiAlMnO} 4, LiMnO 2 and LiMn ₂ O _4, etc.), transition metal elements Two types of composite oxides (eg LiFeMnO ₄ , LiNi _1-x Co _x O ₂ , LiMn _1-y Co _y O ₂ , LiNi _1/3 Co _1/3 Al _1/3 O ₂ and LiNi _0.8 Co _0.15 Al _0.05 O ₂ ) and a composite oxide containing three or more kinds of metal elements [for example, LiMaM'bM''cO ₂ (M, M'and M'' are different transition metal elements, and a + b + c = 1. For example, LiNi _1/3 Mn _1/3 Co _1/3 O ₂ ), etc.}, lithium-containing transition metal phosphates (eg LiFePO ₄ , LiCoPO ₄ , LiMnPO ₄ and LiNiPO ₄ ), transition metals Oxides (eg MnO ₂ and V ₂ O ₅ ), transition metal sulfides (eg MoS ₂ and TiS ₂ ) and conductive polymers (eg polyaniline, polypyrrole, polythiophene, polyacetylene and poly-p-phenylene and polyvinylcarbazole) and the like. However, two or more types may be used in combination.
The lithium-containing transition metal phosphate may be one in which a part of the transition metal site is replaced with another transition metal.

The volume average particle size of the positive electrode active material is preferably 0.01 to 100 μm, more preferably 0.1 to 35 μm, and preferably 2 to 30 μm from the viewpoint of the electrical characteristics of the power storage device. More preferred.

In the present specification, the volume average particle size of the positive electrode active material means the particle size (Dv50) at an integrated value of 50% in the particle size distribution obtained by the microtrack method (laser diffraction / scattering method). The microtrack method is a method for obtaining a particle size distribution using scattered light obtained by irradiating particles with laser light. A microtrack or the like manufactured by Nikkiso Co., Ltd. can be used for measuring the volume average particle size.

The conductive auxiliary agent which may constitute the positive electrode active material layer will be described.
The conductive auxiliary agent is selected from materials having conductivity.
Specifically, metals [nickel, aluminum, stainless steel (SUS), silver, copper, titanium, etc.], carbon [graphite and carbon black (acetylene black, ketjen black, furnace black, channel black, thermal lamp black, etc.), etc.), etc. ], And a mixture thereof, etc., but is not limited to these.
These conductive auxiliaries may be used alone or in combination of two or more. Moreover, you may use these alloys or metal oxides. From the viewpoint of electrical stability, aluminum, stainless steel, carbon, silver, copper, titanium and mixtures thereof are preferable, silver, aluminum, stainless steel and carbon are more preferable, and carbon is even more preferable. Further, these conductive auxiliaries may be those obtained by coating a conductive material (a metal one among the above-mentioned conductive auxiliary materials) around a particle-based ceramic material or a resin material by plating or the like.

The average particle size of the conductive auxiliary agent is not particularly limited, but is preferably 0.01 to 10 μm, more preferably 0.02 to 5 μm, from the viewpoint of the electrical characteristics of the power storage device. , 0.03 to 1 μm, more preferably. In addition, in this specification, "particle diameter" means the maximum distance L among the distances between arbitrary two points on the contour line of a particle. The value of the "average particle size" is the average value of the particle size of the particles observed in several to several tens of fields using an observation means such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM). The calculated value shall be adopted.

The shape (form) of the conductive auxiliary agent is not limited to the particle form, and may be a form other than the particle form, and may be a form practically used as a so-called filler-based conductive resin composition such as carbon nanotubes. Good.

The conductive auxiliary agent may be a conductive fiber whose shape is fibrous.
As the conductive fiber, carbon fiber such as PAN-based carbon fiber and pitch-based carbon fiber, conductive fiber obtained by uniformly dispersing a metal having good conductivity or graphite in synthetic fiber, and a metal such as stainless steel Examples thereof include fibrous metal fibers, conductive fibers in which the surface of organic fibers is coated with metal, and conductive fibers in which the surface of organic fibers is coated with a resin containing a conductive substance. Among these conductive fibers, carbon fibers are preferable. Further, a polypropylene resin kneaded with graphene is also preferable.
When the conductive auxiliary agent is a conductive fiber, its average fiber diameter is preferably 0.1 to 20 μm.

Subsequently, the positive electrode coating layer constituting the coated positive electrode active material will be described.
The positive electrode coating layer contains a polymer compound, and may further contain a conductive material if necessary.
In the coated positive electrode active material, a part or all of the surface of the positive electrode active material is coated with a positive electrode coating layer containing a polymer compound, but in the positive electrode active material layer, for example, the coated positive electrode active material. Even if the substances come into contact with each other, the positive electrode coating layers are not irreversibly bonded to each other on the contact surface, and the bonding is temporary and can be easily loosened by hand. The substances are not fixed to each other by the positive electrode coating layer. Therefore, in the positive electrode active material layer containing the coated positive electrode active material, the positive electrode active materials are not bound to each other.

Examples of the polymer compound constituting the positive electrode coating layer include thermoplastic resins and thermosetting resins. For example, fluororesins, vinyl resins, urethane resins, polyester resins, polyether resins, polyamide resins, epoxy resins, and polyimides. Examples thereof include resins, silicone resins, phenol resins, melamine resins, urea resins, aniline resins, ionomer resins, polycarbonates, polysaccharoids (sodium alginate, etc.) and mixtures thereof. Among these, vinyl resin, urethane resin, polyester resin or polyamide resin are preferable.
Among these, a polymer compound having a liquid absorption rate of 10% or more when immersed in an electrolytic solution and a tensile elongation at break in a saturated liquid absorption state of 10% or more is more preferable.

The liquid absorption rate when immersed in the electrolytic solution is calculated by the following formula by measuring the weight of the polymer compound before and after immersion in the electrolytic solution.
Liquid absorption rate (%) = [(Weight of polymer compound after immersion in electrolyte solution-Weight of polymer compound before immersion in electrolyte solution) / Weight of polymer compound before immersion in electrolyte solution] × 100
The electrolytic solution for determining the liquid absorption rate is preferably a mixed solvent in which ethylene carbonate (EC) and diethyl carbonate (DEC) are mixed in a volume ratio of EC: DEC = 3: 7, and LiPF ₆ as an electrolyte is 1 mol / mol /. An electrolytic solution dissolved so as to have a concentration of L is used.
Immersion in the electrolytic solution for determining the liquid absorption rate is performed at 50 ° C. for 3 days. By immersing at 50 ° C. for 3 days, the polymer compound becomes a saturated liquid absorbing state. The saturated liquid absorbing state means a state in which the weight of the polymer compound does not increase even if it is further immersed in the electrolytic solution.
The electrolytic solution used in manufacturing the lithium ion battery is not limited to the above electrolytic solution, and other electrolytic solutions may be used.

When the liquid absorption rate is 10% or more, lithium ions can easily permeate the polymer compound, so that the ion resistance in the positive electrode active material layer can be kept low. If the liquid absorption rate is less than 10%, the conductivity of lithium ions becomes low, and the performance as a lithium ion battery may not be sufficiently exhibited.
The liquid absorption rate is preferably 20% or more, and more preferably 30% or more.
The preferable upper limit of the liquid absorption rate is 400%, and the more preferable upper limit is 300%.

The tensile elongation at break in the saturated liquid absorption state is obtained by punching the polymer compound into a dumbbell shape and immersing the polymer compound in the electrolytic solution at 50 ° C. for 3 days in the same manner as in the above measurement of the liquid absorption rate to saturate the polymer compound. As a state, it can be measured according to ASTM D683 (test piece shape Type II). The tensile elongation at break is a value calculated by the following formula as the elongation at break until the test piece breaks in the tensile test.
Tensile fracture elongation (%) = [(Test piece length at break-Test piece length before test) / Test piece length before test] x 100

When the tensile elongation at break of the polymer compound in the saturated liquid absorption state is 10% or more, the polymer compound has appropriate flexibility, so that the positive electrode coating layer is peeled off due to the volume change of the positive electrode active material during charging and discharging. It becomes easier to suppress doing.
The tensile elongation at break is preferably 20% or more, and more preferably 30% or more.
Further, the preferable upper limit value of the tensile elongation at break is 400%, and the more preferable upper limit value is 300%.

Among the above-mentioned polymer compounds, those described as coating resins in International Publication No. 2015/005117 can be particularly preferably used as the polymer compounds constituting the positive electrode coating layer of the present invention.

As the conductive material, those listed as the conductive auxiliary agent which may form the positive electrode active material layer can be preferably used.

The ratio of the total weight of the polymer compound and the conductive material to the weight of the positive electrode active material is not particularly limited, but is preferably 2 to 25% by weight.

The ratio of the weight of the polymer compound to the weight of the positive electrode active material is not particularly limited, but is preferably 0.1 to 10% by weight. The ratio of the weight of the conductive material to the weight of the positive electrode active material is not particularly limited, but is preferably 2 to 15% by weight.

The ratio of the weight of the polymer compound contained in the positive electrode coating layer to the weight of the conductive material contained in the positive electrode coating layer is not particularly limited, but is preferably 1 to 10% by weight, preferably 1 to 4% by weight. More preferably.

The conductivity of the positive electrode coating layer is preferably 0.001 to 10 mS / cm, more preferably 0.01 to 5 mS / cm.
The conductivity of the positive electrode coating layer can be determined by the four-terminal method.
When the conductivity of the positive electrode coating layer is 0.001 mS / cm or more, the electrical resistance to the positive electrode active material is not high, and charging / discharging is possible.

The negative electrode active material layer constituting the power storage device of the present invention will be described.
The negative electrode active material layer contains a negative electrode active material that is not bound to each other, and may contain a conductive auxiliary agent, if necessary.
That is, in the negative electrode active material layer constituting the power storage device of the present invention, the negative electrode active materials constituting the negative electrode active material layer are not bound to each other.

The negative electrode active material may be the negative electrode active material itself, or may be a coated negative electrode active material in which a part or all of the surface of the negative electrode active material is coated with a negative electrode coating layer containing a polymer compound. However, it is desirable that it is a coated negative electrode active material.

The thickness of the negative electrode active material layer is not particularly limited, but is preferably 100 to 10,000 μm.

Examples of the negative electrode active material include carbon-based materials [for example, graphite, non-graphitizable carbon, amorphous carbon, calcined resin (for example, phenol resin, furan resin, etc. are calcined and carbonized), cokes (for example, pitch coke, etc.). Needle coke and petroleum coke, etc.), silicon carbide and carbon fiber, etc.], conductive polymers (eg, polyacetylene and polypyrrole, etc.), metals (tin, silicon, aluminum, zirconium, titanium, etc.), metal oxides (titanium oxide, etc.) Lithium-titanium oxides and silicon oxides, etc.) and metal alloys (for example, lithium-tin alloys, lithium-silicon alloys, lithium-aluminum alloys, lithium-aluminum-manganese alloys, etc.) and mixtures of these with carbon-based materials, etc. Can be mentioned.
Among the above-mentioned negative electrode active materials, those which do not contain lithium or lithium ions inside may be pre-doped with a part or all of the active materials containing lithium or lithium ions in advance.

The volume average particle size of the negative electrode active material is preferably 0.01 to 100 μm, more preferably 0.1 to 20 μm, and even more preferably 2 to 10 μm from the viewpoint of the electrical characteristics of the power storage device.

In the present specification, the volume average particle size of the negative electrode active material means the particle size (Dv50) at an integrated value of 50% in the particle size distribution obtained by the microtrack method (laser diffraction / scattering method). The microtrack method is a method for obtaining a particle size distribution using scattered light obtained by irradiating particles with laser light. A microtrack or the like manufactured by Nikkiso Co., Ltd. can be used for measuring the volume average particle size.

Subsequently, the negative electrode coating layer will be described.
The negative electrode coating layer contains a polymer compound, and may further contain a conductive material, if necessary.
In the coated negative electrode active material, a part or all of the surface of the negative electrode active material is coated with a negative electrode coating layer containing a polymer compound, but in the negative electrode active material layer, for example, the coated negative electrode active material. Even if the substances come into contact with each other, the negative electrode coating layers do not irreversibly adhere to each other on the contact surface, and the adhesion is temporary and can be easily loosened by hand. They are not fixed to each other by the negative electrode coating layer. Therefore, in the negative electrode active material layer containing the coated negative electrode active material, the negative electrode active materials are not bound to each other.
As the polymer compound and the conductive material constituting the negative electrode coating layer, the same polymer compounds and conductive materials as those constituting the positive electrode coating layer can be preferably used.

The ratio of the total weight of the polymer compound and the conductive material contained in the negative electrode coating layer is not particularly limited, but is preferably 0.1 to 25% by weight with respect to the weight of the negative electrode active material.

The ratio of the weight of the polymer compound to the weight of the negative electrode active material is not particularly limited, but is preferably 0.1 to 20% by weight.
The ratio of the weight of the conductive material to the weight of the negative electrode active material is not particularly limited, but is preferably 1 to 10% by weight.

The ratio of the weight of the polymer compound contained in the coating layer to the weight of the conductive material contained in the negative electrode coating layer is not particularly limited, but is preferably 10 to 500% by weight, preferably 15 to 35% by weight. More preferred.

The conductivity of the negative electrode coating layer is preferably 0.0001 to 10 mS / cm, more preferably 0.01 to 5 mS / cm.
The conductivity of the negative electrode coating layer can be determined by the four-terminal method.
When the conductivity of the negative electrode coating layer is 0.0001 mS / cm or more, the electrical resistance to the negative electrode active material is not high, and charging / discharging is possible.

Subsequently, the separator layer constituting the power storage device of the present invention will be described.
Materials constituting the separator layer include polyethylene, a microporous film made of polypropylene, a multilayer film of a porous polyethylene film and polypropylene, a non-woven fabric made of polyester fiber, aramid fiber, glass fiber, etc., and silica on their surface. , Alumina, Titania and the like to which ceramic fine particles are attached, and a layer formed of inorganic particles such as silica, Alumina and Titania and having a predetermined thickness and the like.

Next, the current collector layer will be described.
The current collector layer is a portion of the wiring for moving electric power in the power storage tank that is in direct contact with the positive electrode active material layer and / or the negative electrode active material layer.
Examples of the material constituting the current collector layer include conductive materials such as copper, aluminum, titanium, stainless steel, nickel, calcined carbon, conductive polymer and conductive glass, and a resin composed of a conductive agent and a resin. It may be a current collector.
The shape of the current collector layer is not limited as long as it is a surface of the positive electrode active material layer and / or the negative electrode active material layer and can cover all the surfaces adjacent to the current collector layer. It may be a deposited layer made of a sheet-like current collector made of a material having a property and fine particles made of the above-mentioned material having a conductivity.
The thickness of the current collector layer is not particularly limited, but is preferably 50 to 2000 μm.

As the conductive agent constituting the resin current collector, those listed as the conductive auxiliary agents which may constitute the positive electrode active material layer can be preferably used.
The resins constituting the resin current collector include polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polycycloolefin (PCO), polyethylene terephthalate (PET), polyether nitrile (PEN), and polytetra. Fluoroethylene (PTFE), styrene butadiene rubber (SBR), polyacrylic nitrile (PAN), polymethyl acrylate (PMA), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVdF), epoxy resin, silicone resin, or a mixture thereof, etc. Can be mentioned.
From the viewpoint of electrical stability, polyethylene (PE), polypropylene (PP), polymethylpentene (PMP) and polycycloolefin (PCO) are preferable, and polyethylene (PE), polypropylene (PP) and polymethylpentene are more preferable. (PMP).

Subsequently, the electrolytic solution will be described.
As the electrolytic solution, one containing an electrolyte and a non-aqueous solvent used in the production of a lithium ion battery can be used. Further, instead of the electrolytic solution, a known solid electrolyte having lithium ion conductivity can be used.

As the electrolyte, those used in ordinary electrolytes can be used, and preferred ones are lithium salt-based electrolytes of inorganic acids such as _{LiPF 6} , LiBF ₄ , LiSbF ₆ , _{LiAsF 6} and LiClO _4. A sulfonylimide-based electrolyte having a fluorine atom such as LiN (CF ₃ SO ₂ ) ₂ and LiN (C ₂ F ₅ SO ₂ ) ₂ , a sulfonylmethide electrolyte having a fluorine atom such as LiC (CF ₃ SO ₂ ) _3, etc. Can be mentioned. _{Of these, LiPF 6} is preferable from the viewpoint of ionic conductivity at high concentration and thermal decomposition temperature. LiPF ₆ may be used in combination with other electrolytes, but it is more preferable to use LiPF 6 alone.

The electrolyte concentration of the electrolytic solution is not particularly limited, but is preferably 0.5 to 5 mol / L, more preferably 0.8 to 4 mol / L, and further preferably 1 to 2 mol / L. preferable.

As the non-aqueous solvent, those used in ordinary electrolytic solutions can be used, and for example, a lactone compound, a cyclic or chain carbonate, a chain carboxylic acid ester, a cyclic or chain ether, a phosphoric acid ester, and a nitrile can be used. Compounds, amide compounds, sulfones and the like and mixtures thereof can be used.

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

Examples of the cyclic carbonate include propylene carbonate, ethylene carbonate, butylene carbonate and the like.
Examples of the chain carbonate include dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, methyl-n-propyl carbonate, ethyl-n-propyl carbonate, di-n-propyl carbonate and the like.

Examples of the chain carboxylic acid ester include methyl acetate, ethyl acetate, propyl acetate, methyl propionate and the like.
Examples of the cyclic ether include tetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 1,4-dioxane and the like.
Examples of the chain ether include dimethoxymethane and 1,2-dimethoxyethane.

Phosphate esters include trimethyl phosphate, triethyl phosphate, ethyl dimethyl phosphate, diethyl methyl phosphate, tripropyl phosphate, tributyl phosphate, tri (trifluoromethyl) phosphate, tri (trichloromethyl) phosphate, Tri (trifluoroethyl) phosphate, tri (triperfluoroethyl) phosphate, 2-ethoxy-1,3,2-dioxaphosphoran-2-one, 2-trifluoroethoxy-1,3,2- Examples thereof include dioxaphosphoran-2-one and 2-methoxyethoxy-1,3,2-dioxaphosphoran-2-one.
Examples of the nitrile compound include acetonitrile and the like. Examples of the amide compound include DMF and the like. Examples of the sulfone include a chain sulfone such as dimethyl sulfone and diethyl sulfone, a cyclic sulfone such as sulfolane, and the like.
One type of non-aqueous solvent may be used alone, or two or more types may be used in combination.

Among the non-aqueous solvents, lactone compounds, cyclic carbonic acid esters, chain carbonic acid esters and phosphoric acid esters are preferable from the viewpoint of the output of the power storage device and the charge / discharge cycle characteristics. More preferred are lactone compounds, cyclic carbonates and chained carbonates, and particularly preferred is a mixture of cyclic carbonates and chained carbonates. The most preferable is a mixed solution of ethylene carbonate (EC) and dimethyl carbonate (DMC), or a mixed solution of ethylene carbonate (EC) and diethyl carbonate (DEC).

The material constituting the power storage tank is not particularly limited as long as it has the required mechanical strength, and a material generally used as a structural material may be used, for example, cement, concrete, asphalt, and the like. Gypsum, plaster, brick, wood, glass, metal, stone and the like can be used, and two or more of these may be used in combination.
When a metal is used, it is necessary not to electrically connect (also referred to as a short circuit) between the positive electrode active material layer and the negative electrode active material layer or between the cell units. For example, in the case of a metal power storage tank, it is desirable to provide a non-conductive immersion-proof layer over the entire inner surface.

When a lid for sealing the power storage tank is provided on the upper part of the power storage tank, a material similar to the material constituting the power storage tank can be preferably used as the material for forming the lid.
Further, since the lid requires lower mechanical strength than the power storage tank, plastic or the like may be used as a material. A plurality of lids may cover the upper part of the power storage tank.

When a waterproof layer is provided on the power storage tank and the lid, it is desirable that the waterproof layer is made of, for example, polyurethane, polypropylene, ABS rubber, fluororesin, or the like. The thickness of the waterproof layer is not particularly limited, but is preferably about 0.1 to 10 mm.

When the water-proof layer is provided in the power storage tank, it is desirable that the material constituting the water-proof layer is, for example, polyethylene, polypropylene, fluororesin, or the like.

In addition to the power storage layer, current collector layer, and high power section, the power storage tank may be equipped with sensors such as temperature sensors, humidity sensors, and pressure sensors, and temperature control devices such as cooling elements and heating elements. Good.
By installing sensors, it becomes easier to grasp the state of the cell unit, and by using it together with a temperature control device, the state of the cell unit can be optimized for charging and discharging.

The power storage device of the present invention may be installed outdoors, but it is desirable that the power storage device is installed indoors from the viewpoint of suppressing impurities such as moisture and dust from being mixed into the power storage tank.
It is desirable that the temperature and humidity of the space in which the power storage device of the present invention is installed are controlled.

The power storage device of the present invention may be connected to a power control device for controlling the current and voltage flowing through the storage layer. By connecting the power control device to the power storage device of the present invention and performing charging / discharging, charging / discharging can be performed without causing overcharging or overdischarging.
The power control device may be inside the power storage tank or outside the power storage tank.
When the power storage device of the present invention includes sensors such as a pressure sensor and a temperature sensor, and temperature control devices such as a heating element and a cooling element in the power storage tank, the sensors and the temperature control device have the power. It may be connected to a control device.

The total electric capacity of the power storage device of the present invention may be 5 kWh or more, but is preferably 10 kWh to 1 GWh.
The power storage device of the present invention can easily control the total electric capacity and output characteristics by adjusting the size, number and connection method (series or parallel) of storage layers, and the size of the power storage tank. Can be done.

The place where the power storage device of the present invention is installed is not particularly limited, and can be used for power leveling in a place where a high-power generator operates, and is suitable for a power plant, a ship, a submarine, or the like. Can be used. As the power plant, it can be suitably used for a nuclear power plant whose output is hard to fluctuate, a wind power plant whose power generation amount fluctuates drastically, a solar power plant, a solar thermal power plant and the like.
Further, as an uninterruptible power supply, it is suitable for use in medical facilities, data centers, semiconductor factories, etc. where stable power supply is indispensable.
Further, it can be suitably used in an electric station (also referred to as a charging stand, a charging spot, etc.) that supplies electric power to an electric vehicle, an electric propulsion ship, or the like according to a customer's request. By using the power storage device of the present invention for an electric station or the like, the electric station can be separated from the power transmission network of the electric power company, so that an overload on the power transmission network can be avoided.

The method for manufacturing the power storage device of the present invention will be described.
The method for manufacturing the power storage device of the present invention includes a power storage tank construction step for constructing a power storage tank, and a positive electrode active material layer and a separator comprising a positive electrode active material that is not bound to each other in the power storage tank. A power storage device comprising a storage layer arrangement step of arranging a storage layer including one or more cell units in which a layer and a negative electrode active material layer including a negative electrode active material not bonded to each other are arranged in this order. In the manufacturing method, the power storage layer arranging step includes a step of directly arranging the positive electrode active material layer, the separator layer, and the negative electrode active material layer in the power storage tank, and is arranged in the power storage layer arranging step. At least one of the electric capacities of the cell unit is set to 5 kWh or more.

First, the power storage tank construction process will be described.
In the method for manufacturing the power storage device of the present invention, the power storage tank is constructed in the power storage tank construction process.
The method of constructing the power storage tank is not particularly limited, but a method generally adopted as a construction method of a structure can be used. For example, a formwork is made of wood or the like, and the formwork is formed in the formwork. An example is a method in which concrete or the like before hardening is poured and hardened.
Further, since the storage layers are sequentially arranged in the power storage tank by the subsequent storage layer arrangement step, it is desirable to arrange the high power unit in advance at the bottom of the power storage tank.
Further, the power storage tank may be provided with a space for laying wiring or the like for controlling a high power unit, sensors, temperature adjusting devices and the like, if necessary.

In the power storage tank construction step, a waterproof layer may be further provided in the power storage tank.
The waterproof layer may be provided on the surface of the power storage tank or may be provided inside.
Therefore, a waterproof layer may be provided inside the power storage tank in the power storage tank construction process, or a waterproof layer is provided on the inner surface and / or outer surface of the power storage tank after the power storage tank construction process is completed. The process may be performed separately.

In the power storage tank construction step, an immersion-proof layer may be further provided in the power storage tank.
The immersion-proof layer is preferably provided inside the waterproof layer (on the storage layer side), and the step of providing the immersion-proof layer is preferably performed after the step of providing the waterproof layer.

Subsequently, the storage layer arrangement process will be described.
In the storage layer arrangement step, the positive electrode active material layer, the separator layer, and the negative electrode which are not bonded to each other contain the positive electrode active material which is not bonded to each other in the power storage tank constructed by the power storage tank construction process. The negative electrode active material layer containing the active material is directly arranged. From the viewpoint of easily increasing the size of the power storage device, in the step of directly arranging the positive electrode active material layer, the separator layer and the negative electrode active material layer in the power storage tank, the material to be the positive electrode active material layer and the above. It is desirable that the material to be the negative electrode active material layer is sequentially charged into the power storage tank via the separator layer.

In the method for manufacturing an electric power storage device of the present invention, an active material layer is formed by using active materials that are not bound to each other in the storage layer arrangement step. Therefore, since the positive electrode active material layer and the active material constituting the negative electrode active material layer are not bound to each other, the active material layer does not peel off or crack due to the breaking of the binding, and the thickness of the active material layer is higher than before. Can be thickened.
Further, since it is not necessary to bind the active material to the positive electrode active material layer and the negative electrode active material layer with a binder or the like, a slurry containing a binder, which has been an indispensable process in the production of a conventional lithium ion battery. It is not necessary to go through the steps of applying the above-mentioned material to the surface of the current collector and drying or firing it. Therefore, the material to be the positive electrode active material layer and the material to be the negative electrode active material layer are sequentially put into the power storage tank so as to pass through the separator, and are laminated in a layered manner (power storage of the present invention). A cell unit) in a method of manufacturing an apparatus can be manufactured. At this time, since a drying device or a firing device for drying and firing the slurry is not required, the limit size capable of producing the positive electrode active material layer and the negative electrode active material layer is the above-mentioned drying device, firing device, or the like. There are no restrictions. Therefore, it is possible to manufacture an active material layer having a larger plan view size than the conventional one. From the above, in the method for manufacturing the power storage device of the present invention, at least one of the electric capacities of the cell unit can be set to 5 kWh or more.

In carrying out the step of directly arranging the positive electrode active material layer, the separator layer and the negative electrode active material layer in the power storage tank, a movable arm is laid on the power storage tank, and the positive electrode is used by using the movable arm. The active material layer, the separator layer and the negative electrode active material layer may be arranged directly in the power storage tank.

The storage layer arrangement step will be described with reference to FIGS. 3 (a), 3 (b), 4 (a), 4 (b), 5 (a), and 5 (b).
First, the step of directly arranging the positive electrode active material layer in the power storage tank will be described with reference to FIGS. 3 (a) and 3 (b).

3 (a) and 3 (b) are schematic views schematically showing an example of a step of directly arranging the positive electrode active material layer in the power storage tank, which constitutes the method for manufacturing the power storage device of the present invention. is there.
As shown in FIG. 3A, a strong electric current portion 50 for moving a current from the electric power storage tank 10 to the outside is formed at the bottom of the electric power storage tank 10, and a current collector layer 30 is provided on the upper portion thereof. ing. Then, the material 21a to be the positive electrode active material layer is directly put into the upper surface of the current collector layer 30, and this is developed on the current collector layer 30 to have a uniform thickness. The material 21a to be the positive electrode active material layer may not contain a binder, but may contain a positive electrode active material and, if necessary, a conductive auxiliary agent.
By not including the binder in the material 21a to be the positive electrode active material layer, a positive electrode active material layer containing the positive electrode active material which is not bound to each other can be obtained.
Examples of the binder include polyvinylidene fluoride (PVdF), styrene-butadiene rubber (SBR), polyvinyl alcohol (PVA), carboxymethyl cellulose (CMC), polyvinylpyrrolidone (PVP), and polytetrafluoroethylene (PTFE). It is desirable that these are not contained in the material to be the positive electrode active material layer and the positive electrode active material layer.
By going through the steps shown in FIG. 3A, the positive electrode active material layer 21 is formed on the upper surface of the current collector layer 30 as shown in FIG. 3B.
In FIG. 3A, the material 21a to be the positive electrode active material layer is shown in a shape like a droplet, but the material 21a to be the positive electrode active material layer is not limited to a liquid material and is a powder. There may be.

Subsequently, a step of directly arranging the separator layer in the power storage tank will be described with reference to FIGS. 4 (a) and 4 (b). The step shown in FIG. 4 (a) is performed following FIG. 3 (b).
4 (a) and 4 (b) are perspective cross-sectional views schematically showing an example of a step of directly arranging the separator layer in the power storage device, which constitutes the method for manufacturing the power storage device of the present invention. ..
As shown in FIG. 4A, a strong current portion 50, a current collector layer 30, and a positive electrode active material layer 21 are formed in the power storage tank 10 from the lower side in this order. Then, the material 22a to be the separator layer is directly put onto the upper surface of the positive electrode active material layer 21, and if necessary, this is developed on the positive electrode active material layer 21 to obtain a uniform thickness. The material 22a to be the separator layer may be a material obtained by winding a porous film made of polyethylene or polypropylene on a roll, or may be a material obtained by mixing inorganic particles such as alumina with a non-aqueous solvent, if necessary. Good.
By going through the steps shown in FIG. 4A, the separator layer 22 is formed on the upper surface of the positive electrode current collector layer 21 as shown in FIG. 4B.
In FIG. 4A, the material 22a to be the separator layer is shown in a shape like a droplet, but the material 22a to be the separator layer is not limited to a liquid material and may be a powder. ..

Subsequently, a step of directly arranging the negative electrode active material layer in the power storage tank will be described with reference to FIGS. 5 (a) and 5 (b). The step shown in FIG. 5 (a) is performed following FIG. 4 (b).
5 (a) and 5 (b) are perspective cross-sectional views schematically showing an example of a step of directly arranging the negative electrode active material layer in the power storage device, which constitutes the method for manufacturing the power storage device of the present invention. Is.
As shown in FIG. 5A, a strong current section 50, a current collector layer 30, a positive electrode active material layer 21, and a separator layer 22 are formed in this order from the lower side in the power storage tank 10. Then, the material 23a to be the negative electrode active material layer is directly put into the upper surface of the separator layer 22, and this is developed on the separator layer 22 to have a uniform thickness. The material 23a to be the negative electrode active material layer may not contain a binder, but may contain a negative electrode active material and, if necessary, a conductive auxiliary agent.
By not including the binder in the material 23a to be the negative electrode active material layer, a negative electrode active material layer containing negative electrode active materials that are not bound to each other can be obtained.
By going through the steps shown in FIG. 5 (a), as shown in FIG. 5 (b), the negative electrode active material layer 23 is formed on the upper surface of the separator layer 22, and the positive electrode active material layer 21 is formed in the power storage tank 10. , The cell unit 30 in which the separator layer 22 and the negative electrode active material layer 23 are arranged in this order is formed.
In FIG. 5A, the material 23a to be the negative electrode active material layer is shown in a shape like a droplet, but the material 23a to be the negative electrode active material layer is not limited to a liquid material and is a powder. There may be.

In the method for manufacturing the power storage device of the present invention, the power storage tank is configured so that the horizontal internal dimensions of the power storage tank change stepwise in the vertical direction of the power storage tank in the power storage tank construction process. In the process of arranging the storage layer, a plurality of cell units are arranged so as to follow the horizontal internal dimensions of the power storage tank, and one cell is constructed so that the shape of the inner wall surface and the bottom surface thereof is substantially stepped. It is desirable to arrange a support plate having substantially the same area as the horizontal area of one cell unit between the unit and another cell unit arranged on the lower side in the vertical direction.
With this configuration, as shown in FIG. 2, a support plate 31a having an area substantially the same as the horizontal area of the power storage tank is arranged on the bottom surface of the power storage tank 10 having a substantially stepped shape. Therefore, the weight of the cell unit 20a arranged on the support plate 31a can be distributed to the wall surface or the bottom surface constituting the power storage tank 10. Further, by arranging the support plate 31b, the weight of the cell unit 20b arranged on the support plate 31b can be dispersed on the wall surface or the bottom surface constituting the power storage tank 10.
Therefore, even when a large number of cell units are stacked, it is possible to prevent the cell units arranged on the lower side in the vertical direction from being excessively loaded from the cell units arranged on the upper side in the vertical direction.

The support plate may have enough rigidity to disperse the load of the cell unit arranged on the upper side to the cell unit arranged on the lower side without transmitting it to the power storage tank, and the material and thickness of the support plate may be sufficient. The size is not particularly limited.

Subsequently, a specific method for directly arranging the positive electrode active material layer, the separator layer, and the negative electrode active material layer in the power storage tank in the storage layer arranging step will be described.
As a method of directly arranging the positive electrode active material layer, the separator layer and the negative electrode active material layer in the power storage tank, the material to be the layer to be placed is mixed with a non-aqueous solvent or the like as necessary and put into the power storage tank. However, specifically, an arm, a trolley, or the like installed on the power storage tank can be used.

First, a case where the storage layer arrangement step is performed using the arm installed on the power storage tank will be described with reference to FIG.
FIG. 6 is a perspective sectional view schematically showing an example of a storage layer arrangement process constituting the method for manufacturing the power storage device of the present invention.
As shown in FIG. 6, the arm 60 installed on the power storage tank 10 is connected to a transport pipe 61 extending from a tank (not shown) for storing the material 21a serving as the positive electrode active material layer, and the arm 60 21a, which is the positive electrode active material layer, is directly put into the power storage tank 10 while freely moving in the power storage tank 10. At this time, the distance measuring device 62 provided on the lower surface of the arm 60 measures the distance from the arm 60 to the material 21a to be the positive electrode active material layer charged into the power storage tank 10, thereby charging the positive electrode activity. The thickness of the positive electrode active material layer 21 can be controlled by adjusting the amount of the material 21a to be the material layer.
The type of rangefinder is not particularly limited, but the laser type is desirable from the viewpoint of measurement accuracy.

Subsequently, a case where the storage layer arrangement step is performed using the trolley installed on the power storage tank will be described with reference to FIG. 7.
FIG. 7 is a perspective sectional view schematically showing another example of the storage layer arrangement process constituting the method for manufacturing the power storage device of the present invention.
As shown in FIG. 7, two parallel rails 80 are laid on the power storage tank 10, and a carriage 70 is installed straddling between the two rails 80. The carriage 70 can freely move along the longitudinal direction of the rail 80. Further, the carriage 70 is provided with an injection port 71 capable of injecting a material 21a to be a positive electrode active material layer supplied from a material tank (not shown) into the power storage tank 10, and further, from the injection port 71 by an arm 72. The distance to the surface of the power storage tank 10 to which the raw material is injected can be adjusted.
Further, a range finder 73 is provided in the vicinity of the injection port 71, and it is possible to grasp how thick the material injected from the injection port 71 is in the power storage tank 10.
Therefore, by using the carriage 70 shown in FIG. 7, the positive electrode active material layer, the separator layer, and the negative electrode active material layer can be arranged in the power storage tank 10 with an arbitrary thickness.
The type of rangefinder is not particularly limited, but the laser type is desirable from the viewpoint of measurement accuracy.

The material to be the positive electrode active material layer may not contain a binder so that the positive electrode active materials are not bound to each other, and may contain a non-aqueous solvent or a conductive auxiliary agent, if necessary. Further, as the positive electrode active material, a coated positive electrode active material in which a part or all of the surface of the positive electrode active material is coated with a positive electrode coating layer made of a polymer compound (and a conductive material added as needed) may be used. Good.

The material to be the negative electrode active material layer may not contain a binder so that the negative electrode active materials are not bound to each other, and may contain a non-aqueous solvent or a conductive auxiliary agent, if necessary. Further, as the negative electrode active material, a coated negative electrode active material in which a part or all of the surface of the negative electrode active material is coated with a negative electrode coating layer made of a polymer compound (and a conductive material added as needed) may be used. Good.

When forming the positive electrode active material layer and the negative electrode active material layer in the power storage tank, if necessary, pressure is applied to the surface of the formed positive electrode active material layer or the negative electrode active material layer to form an adjacent layer. Adhesion may be improved.

Examples of the material to be the separator layer include a material that functions as a separator layer after being put into an electric power storage tank and a material obtained by winding a sheet-like material that functions as a separator layer around a core. The separator layer can be directly arranged in the power storage tank by directly charging and laying it in the storage tank. Examples of those that function as a separator layer in the power storage tank include those obtained by mixing an inorganic powder such as alumina or an inorganic powder such as alumina with a non-aqueous solvent. Further, a solid electrolyte having lithium ion conductivity may be used.
Examples of the sheet-like material that functions as a separator layer include a porous film obtained by drawing a polymer compound after extrusion molding.
When an inorganic powder such as alumina or a solid electrolyte is used as the separator layer, it is desirable to densely fill the separator layer with inorganic particles so that the negative electrode active material and / or the positive electrode active material does not move.

In the method for manufacturing the power storage device of the present invention, the power storage tank construction step and the storage layer arrangement step may be performed in two or more times, or the power storage tank construction step and the storage layer placement step may be alternately performed. ..
For example, in the first power storage tank construction step, a power storage tank corresponding to the size of the storage layer to be arranged in the first power storage layer placement step is constructed, and then in the second power storage tank construction step, 2 By constructing the power storage tank corresponding to the size of the power storage layer to be arranged in the second power storage layer placement process, the power storage tank is constructed in the second power storage tank construction process without destroying the power storage tank once constructed. Wiring for arranging a high power unit, various sensors, temperature control equipment, etc. can be provided inside the power storage tank.

In the method for manufacturing the power storage device of the present invention, an electrolytic solution composed of a non-aqueous solvent and an electrolyte may be charged into the power storage tank. The timing of charging the electrolytic solution into the power storage tank is not particularly limited, but it is desirable to perform the electrolytic solution in parallel with the storage layer arranging step or after the storage layer arranging step.
As the electrolytic solution to be charged into the electric power storage tank, the same electrolytic solution as the electrolytic solution constituting the electric power storage device of the present invention can be preferably used.

The method for manufacturing the power storage device of the present invention may further include a step of directly arranging the current collector layer in the power storage tank in the storage layer arranging step.
By providing a step of directly arranging the current collector layer in the power storage tank, the storage layers arranged by the storage layer arrangement step can be connected in series, so that a power storage device having a high discharge voltage can be manufactured. be able to.
At this time, it is desirable to arrange the storage layer by vertically stacking a plurality of cell units so that the positive electrode active material layer and the negative electrode active material layer face each other via the current collector layer.

In the storage layer arrangement process, the process of directly arranging the current collector layer in the power storage tank includes a method of directly installing the film-shaped current collector in the power storage tank and power storage of the material to be the current collector layer. This can be done by a method such as putting it directly into the tank. As a method of directly charging the material to be the current collector layer into the power storage tank, for example, when the material constituting the current collector layer is a resin current collector, a mixture of a conductive agent and a resin is used as a resin. A method of directly charging a resin heated to a melting point or a softening point or higher (hereinafter, also referred to as a high-temperature resin) into an energy storage tank can be mentioned.
When the high-temperature resin is put into the power storage tank, a resin current collector composed of a conductive agent and a resin is formed as the cooling progresses. At this time, in order to make the thickness of the resin current collector, which is a cooling material, uniform, the high-temperature resin is slid in the horizontal direction by applying a squeegee or the like to the high-temperature resin charged in the power storage tank. The thickness may be adjusted in the state.
As a method of directly charging the high-temperature resin into the power storage tank, in the storage layer arrangement step, the material to be the positive electrode active material layer, the material to be the separator layer, and the material to be the negative electrode active material layer are directly charged into the power storage tank. A method similar to the method used for the above can be preferably used.

In the storage layer arrangement step, when the current collector layer is directly arranged in the power storage tank, a plurality of cell units are provided so that the positive electrode active material layer and the negative electrode active material layer face each other via the current collector layer. It is desirable to stack the cell units of the above in the vertical direction.

The method for manufacturing the power storage device of the present invention may include a step of arranging the high power unit directly in the power storage tank.
By providing the high power unit, a current can be taken out from the power storage layer. Further, if necessary, a plurality of cell units and a plurality of storage layers can be connected in parallel.
As a method of arranging the strong current part directly in the power storage tank, a method of connecting the strong current part to the current collector layer or a part of the current collector layer so as not to come into contact with the positive electrode current collector and the negative electrode current collector. , A method in which the non-contact portion is used as a high electric power portion and the like can be mentioned. Examples of the method of connecting the high current portion to the current collector layer include a method of fixing the high current portion separately prepared to the surface of the current collector layer by means such as adhesion and welding.
The method of fixing the strong current portion to the surface of the current collector layer is not particularly limited, and the strong current portion may be adhered using a conductive adhesive, or may be brought into contact by welding or the like. When the conductivity of the current collector layer is not sufficient, nickel vapor deposition or the like may be applied to the region of the current collector layer in contact with the strong current portion to increase the conductivity.

In the method for manufacturing the power storage device of the present invention, it is desirable that the storage layer arrangement step is performed in an atmosphere having a dew point of −40 ° C. or lower.
As a method of performing the storage layer arrangement process in an atmosphere where the dew point is -40 ° C or less, before arranging the power storage tank, a dry air chamber capable of keeping the dew point at -40 ° C or less is constructed, and the dry air chamber is installed. A method of performing the power storage tank construction process and storage layer placement process inside, or covering the power storage tank with a tent-like structure made of a material with low moisture permeability, and inflowing gas with a dew point of -40 ° C or less inside. Examples thereof include a method of maintaining the inside of the tent-shaped structure at a positive pressure.

The power storage facility of the present invention is characterized by comprising the power storage device of the present invention.
Since the power storage equipment of the present invention includes the power storage device of the present invention, it is excellent in power storage efficiency and power storage density.
For example, the room and the building in which the power storage device of the present invention is stored are the power storage equipment of the present invention, and by constructing the power storage device adjacent to a medical facility, a semiconductor factory, a data center, etc. It can function as an uninterruptible power supply.

The power storage device of the present invention is particularly useful as an uninterruptible power supply device in medical facilities, semiconductor factories, data centers, etc., and a power storage device used for peak shifts in power plants, etc.

1, 2 Power storage device 10 Power storage tank 20, 20a, 20b, 20c Cell unit 21 Positive electrode active material layer 22 Separator layer 23 Negative electrode active material layer 30 Current collector layer 31a, 31b Support plate 40 Power storage layer 50 High power section 60, 72 Arm 61 Transport pipe 62, 73 Rangefinder 70 Cart 71 Injection port 80 Rail

Claims (12)

The power storage tank construction process for constructing the power storage tank and
In the power storage tank, a positive electrode active material layer containing a positive electrode active material that is not bound to each other, a separator layer, and a negative electrode active material layer containing a negative electrode active material that is not bound to each other are arranged in this order. It is a method of manufacturing a power storage device including a storage layer arranging step of arranging a storage layer including one or more of the cell units.
The positive electrode active material and the negative electrode active material are compounds capable of inserting and removing lithium ions.
The storage layer arrangement step includes a step of directly arranging the positive electrode active material layer, the separator layer, and the negative electrode active material layer in the power storage tank.
A method for manufacturing an electric power storage device, characterized in that at least one of the electric capacities of the cell unit arranged in the storage layer arrangement step is 5 kWh or more. In the step of directly arranging the positive electrode active material layer, the separator layer and the negative electrode active material layer in the power storage tank, the material to be the positive electrode active material layer and the material to be the negative electrode active material layer are separated into the separator layer. The method for manufacturing an power storage device according to claim 1, wherein the power storage tank is sequentially charged into the power storage tank via the above. The storage layer arranging step further includes a step of arranging the current collector layer directly in the power storage tank.
In the storage layer arrangement step, the plurality of cell units are vertically arranged so that the positive electrode active material layer of the cell unit and the negative electrode active material layer of another cell unit face each other via the current collector layer. The method for manufacturing an energy storage device according to claim 1 or 2, wherein the storage layers are arranged in a stack in the direction. The method for manufacturing an energy storage device according to claim 3, wherein the current collector layer is a resin current collector composed of a conductive agent and a resin. The invention according to any one of claims 1 to 4, wherein at least one of the positive electrode active material and the negative electrode active material is a coating active material whose surface is partially or wholly covered with a coating layer containing a polymer compound. How to make a power storage device. A power storage device in which a power storage layer including one or more cell units in which a positive electrode active material layer, a separator layer, and a negative electrode active material layer are arranged in this order is stored in a power storage tank.
The positive electrode active material layer comprises a positive electrode active material that is not bound to each other.
The negative electrode active material layer contains a negative electrode active material that is not bound to each other.
The positive electrode active material and the negative electrode active material are compounds capable of inserting and removing lithium ions.
A power storage device characterized in that at least one of the electric capacities of the cell unit is 5 kWh or more. The power storage device according to claim 6, wherein at least one of the positive electrode active material and the negative electrode active material is a coating active material whose surface is partially or wholly covered with a coating layer containing the polymer compound. .. The power storage device according to claim 6 or 7, wherein the power storage tank is provided with a waterproof layer. A plurality of the cell units are laminated in the vertical direction so that the positive electrode active material layer of one cell unit and the negative electrode active material layer of the other cell unit face each other via the current collector layer. The power storage device according to any one of claims 6 to 8, which constitutes a power storage layer. The power storage device according to claim 9, wherein the current collector layer is composed of a resin current collector composed of a conductive agent and a resin. The internal dimensions of the power storage tank follow changes in the horizontal area of the plurality of cell units.
The horizontal area of one cell unit is larger than the horizontal area of the other cell units located vertically below.
The power storage device according to claim 9 or 10, wherein a support plate having substantially the same area as the horizontal area of the one cell unit is arranged on the lower side in the vertical direction of the one cell unit. A power storage facility comprising one or more of the power storage devices according to any one of claims 6 to 11.

Images