JP2010278300A - Method of manufacturing lithium ion capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a lithium ion capacitor capable of acquiring a low internal resistance and a flat and smooth electrode layer at low cost. <P>SOLUTION: The manufacturing method includes a step of forming a positive electrode layer 3 containing a positive electrode active material capable of adsorbing/desorbing lithium ions or anions on at least one surface of a positive electrode collector base material 2 and forming a first electrode and a second electrode, respectively, a step of forming a negative electrode layer 6 containing a negative electrode active material capable of absorbing/releasing lithium ions on both surfaces of a negative electrode collector base material 5 and forming a through hole passing through the negative electrode collector base material from a negative electrode layer formed on one surface of the negative collector base material and reaching the negative electrode layer formed on the other surface to form a negative electrode, a step of forming a battery body by laminating a first separator, a source of supplying lithium ions, a negative electrode, and second separator in order on a surface of the positive electrode layer of the first positive electrode and laminating a second positive electrode facing the positive electrode layer on the second separator side, and a step of immersing the battery body in an electrolysis solution with lithium salt dissolved in a nonaqueous solvent. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a lithium ion capacitor having a configuration in which a lithium secondary battery and an electric double layer capacitor are combined.

  An electric double layer capacitor is composed of a positive electrode and a negative electrode having a sheet-like electrode layer made of a carbon material such as activated carbon and a binder, a porous separator that electrically insulates both electrodes, and an electrolyte solution impregnated in these. It is configured to charge / discharge the capacitance of the electric double layer generated at the interface between the two electrodes and the electrolytic solution as ions in the electrolytic solution move between the electrodes. An electric double layer capacitor that performs such a charge / discharge operation does not involve an electrochemical reaction, and therefore has excellent charge / discharge rate characteristics and cycle characteristics. For this reason, it is used as a backup power source for electronic devices and as a power source for various transport equipment including automobiles. However, the energy density is lower than that of a lithium ion battery.

On the other hand, lithium secondary batteries generally use a lithium-containing metal oxide such as LiCoO ₂ as a positive electrode and a carbon material such as graphite as a negative electrode. During charging, lithium is supplied from the lithium-containing metal oxide of the positive electrode to the negative electrode. In addition, lithium ion insertion and desorption reactions in which lithium in the negative electrode is returned to the positive electrode during discharge are used. Since this lithium secondary battery has a high voltage and a high energy density, it is widely used in power supplies for portable devices, electric tools, home appliances, and the like. However, while the energy density is high, there are problems in output characteristics and cycle characteristics.

  In recent years, a lithium ion capacitor (hereinafter referred to as LIC) in which a lithium battery and an electric double layer capacitor are combined has been actively developed. This LIC is a hybrid type capacitor in which activated carbon for an electric double layer capacitor is used as a positive electrode active material and a carbon material for a lithium ion battery is used as a negative electrode active material. In this LIC, since the negative electrode potential can be lowered and a high cell voltage can be obtained by doping lithium ions into the negative electrode active material, the energy density can be improved.

  In a conventional LIC, the positive and negative electrode current collectors each have a hole penetrating the front and back surfaces, and a metal lithium foil is brought into contact with these electrodes to dope lithium ions, and the lithium ions are brought into contact by electrochemical contact. Lithium ions are doped by passing through the positive electrode or the negative electrode. For this reason, an expanded metal, a punching metal, or the like having a hole through which lithium ions are transmitted is used as the current collector (see, for example, Patent Document 1).

JP 2006-286919 A (page 4, FIG. 3)

  In a conventional LIC, a porous metal sheet such as expanded metal or punching metal is used as a current collector. Compared to the case where a smooth metal foil used for a general electric double layer capacitor is used as a current collector. As a result, there is a problem that the cross-sectional area of the conductive portion is remarkably reduced. In a porous metal sheet such as an expanded metal or a punching metal, the cross-sectional area of the conductor is significantly reduced as compared with a metal sheet before processing. Therefore, the electrical resistance of the current collector is higher than when a smooth metal foil is used. As a result, there is a problem that the internal resistance of the LIC becomes high and it becomes difficult to input / output a large current, or heat is generated inside and the temperature of the LIC rises. There is also a problem that the process of coating and forming the electrode layer on the current collector becomes complicated. When applying a paste-like electrode layer material on a current collector, if the current collector is a porous material such as expanded metal or punched metal having a large aperture ratio, a smooth electrode layer cannot be obtained by a single application. The surface of the electrode layer is uneven, which causes a decrease in charge / discharge characteristics. On the other hand, it is conceivable to apply a plurality of times such as filling the hole portion of the porous metal sheet by the first coating and obtaining a smooth electrode layer having a predetermined thickness by the second and subsequent coatings. As the number of manufacturing processes increases, the yield rate decreases and the cost increases.

  The present invention has been made to solve the above-described problems, and provides a method for manufacturing a lithium ion capacitor capable of obtaining a low internal resistance and obtaining a smooth electrode layer at low cost. it can.

  The method of manufacturing a lithium ion capacitor according to the present invention includes forming a positive electrode layer containing a positive electrode active material capable of adsorbing and desorbing lithium ions or anions on at least one surface of a positive electrode current collector substrate, and And forming a negative electrode layer containing a negative electrode active material capable of occluding and releasing lithium ions on both surfaces of the negative electrode current collector substrate, and formed on one surface of the negative electrode current collector substrate. A step of forming a negative electrode by forming a perforation that penetrates the negative electrode current collecting base material from the negative electrode layer to reach the negative electrode layer formed on the other surface, and a first in order from the surface of the positive electrode layer of the first positive electrode A battery body by stacking the second positive electrode with the positive electrode layer facing the separator, the lithium ion supply source, the negative electrode, the second separator, and the second separator, and the battery body in a non-aqueous solvent Lithium salt Is obtained by a step of impregnating the solution was an electrolytic solution.

  In the method for producing a lithium ion capacitor according to the present invention, a negative electrode layer containing a negative electrode active material capable of occluding and releasing lithium ions or anions is formed on both sides of the negative electrode current collector substrate, and one of the negative electrode current collector substrates is formed. A negative electrode current collecting base material comprising a step of forming a negative electrode that forms perforations that penetrate the negative electrode current collecting base material from the negative electrode layer formed on the surface and reach the negative electrode layer formed on the other surface. Has a large cross-sectional area compared to the porous metal sheet, so that a low internal resistance is obtained, and when the negative electrode layer is formed, the negative electrode current collecting substrate is smooth, so that a smooth electrode layer can be obtained at low cost. Can do. Moreover, since the positive electrode current collecting base material is not perforated, high capacity can be obtained for both the positive electrode and the negative electrode even in charge / discharge with a large current.

It is a cross-sectional schematic diagram of the lithium ion capacitor in Embodiment 1 of this invention. It is a schematic diagram of a metal mold | die in Embodiment 1 of this invention. It is a schematic diagram which shows the process of forming perforation in the negative electrode in Embodiment 1 of this invention. It is a schematic diagram of the roll press in Embodiment 2 of this invention. It is a cross-sectional schematic diagram of the winding type lithium ion capacitor in Embodiment 4 of this invention. It is a cross-sectional schematic diagram of the winding type lithium ion capacitor in Embodiment 4 of this invention.

Embodiment 1 FIG.
FIG. 1 schematically shows a cross section of a lithium ion capacitor (LIC) according to Embodiment 1 for carrying out the present invention. FIG. 1 schematically shows a single unit of the LIC, but the structure of FIG. 1 is laminated or a structure in which long electrodes are wound so as to reach a necessary capacity for the entire LIC cell. It is also possible.

  First, a method for producing a positive electrode will be described. The positive electrode 1 has the same configuration as that of a normal electric double layer capacitor. For example, a positive electrode layer 3 containing a positive electrode active material is applied and formed on the surface of a positive electrode current collector substrate 2 made of a smooth aluminum foil. As the positive electrode active material, a carbon material having a large surface area and a large capacitance can be used. As the carbon material, for example, particulate activated carbon having a diameter of about 10 μm, water vapor activated activated carbon, alkaline activated carbon, nanogate carbon, and the like can be used. That is, the positive electrode active material is not limited to these as long as the material can adsorb and desorb lithium ions or anions. Here, adsorption and desorption indicate that lithium ions or anions are reversibly supported. The positive electrode layer 3 is formed by binding to the entire area of one surface of the positive electrode current collector substrate 2 using a paste in which a positive electrode active material is uniformly dispersed in a binder by a rolling method, a coating method, a molding method, or the like. Therefore, the outer shape of the positive electrode layer 3 is the same as that of the positive electrode current collector substrate 2 except for the current terminal portion. The binder may be a fluororesin such as PTFE (polytetrafluoroethylene), SBR (styrene butadiene rubber), acrylic synthetic rubber, PVDF (polyvinylidene fluoride), or the like. Moreover, the thickness of the positive electrode layer 3 is about 100 μm, and is generally in the range of 50 to 150 μm.

  Next, a method for manufacturing the negative electrode will be described. As for the negative electrode 4, the negative electrode layer 6 containing a negative electrode active material is apply | coated and formed on both surfaces of the negative electrode current collection base material 5 comprised, for example with smooth copper foil. The typical thickness of the negative electrode current collecting base material 5 is 10 to 50 μm, and is appropriately determined depending on the charge / discharge current when charging / discharging the electric double layer capacitor. When the charge / discharge current is large, a thick negative electrode current collector is used to reduce the internal resistance. When the charge / discharge current is small, the thinnest possible one is used from the viewpoint of improving the energy density. It is done. As the negative electrode active material, a material capable of inserting and extracting lithium ions can be used. Occlusion and release as used herein refer to lithium desorption by an electrochemical reaction. As the negative electrode active material, a material capable of removing and inserting lithium by an electrochemical reaction can be used. In the present embodiment, graphite is used. In addition, for example, negative electrode active materials used as negative electrodes of lithium ion batteries, such as amorphous carbon, tin, and silicon alloys, can be used. Moreover, the optimal thickness of an electrode layer (a positive electrode layer and a negative electrode layer) changes with the kind etc. of carbon to be used by a positive electrode and a negative electrode. Here, the thickness of the negative electrode layer 6 is about 70 μm.

  Since the positive electrode layer and the negative electrode layer have high porosity after coating and the bulk density is too low, smooth roll (calendar roll) pressing is performed at a predetermined temperature in order to adjust the porosity to an appropriate one.

  Further, in the negative electrode, a large number of perforations are formed as a path for ions to diffuse into the negative electrode current collector base and the negative electrode layer in order to allow lithium ions to permeate. FIG. 2 is a schematic diagram of a mold 10 for forming perforations in the negative electrode in the present embodiment. In FIG. 2, a large number of protrusions 12 for making perforations are erected on the mold base 11. FIG. 3 is a schematic diagram showing a step of forming perforations in the negative electrode using the mold 10 shown in FIG. The negative electrode 4 is disposed on the projection 12 that stands on one surface of the mold base 11, the acrylic plate 13 is further disposed thereon, and the smooth die 14 disposed on the acrylic plate 13 is disposed, The mold 10 and the smooth mold 14 are pressurized to form perforations in the negative electrode 4. The shape of the protrusion 12 is preferably a shape such as a cylinder, a quadrangular prism, a cone, or a quadrangular pyramid. However, the shape is not limited thereto, and any shape may be used as long as the negative electrode can be efficiently drilled. Further, the tip of the protrusion does not need to be sharp, and may have a rounded shape or a flat shape.

  As described above, after the press working for adjusting the porosity of the negative electrode layer, the negative electrode may be perforated, but the negative electrode after the coating before the press working is pressed at a predetermined temperature and pressure. Therefore, the porosity adjustment of the negative electrode layer and the perforation formation of the negative electrode can be simultaneously performed. It is also possible to adjust the porosity of the negative electrode layer to an appropriate porosity by forming the perforations in the negative electrode after completion of the coating before the press work and then performing the press work.

  The press working of the positive electrode layer and the negative electrode layer and the press for forming the perforations of the negative electrode can be performed by a flat plate press. However, if performed by a roll press of a roll mold, an electrode having a larger area is used. Can be efficiently pressed. In any pressing method, the porosity and thickness of the electrode layer can be controlled by adjusting the pressing pressure, temperature, gap between rolls, number of presses, and the material and thickness of the spacer between the mold and the electrode. When forming the perforations, it is possible to freely adjust the aperture ratio of the perforations of the negative electrode. In this embodiment, no perforation is formed in the positive electrode. For this reason, input / output with a large current is possible without impairing the capacity of the positive electrode.

  As shown in FIG. 1, metal lithium foils 8 are disposed on the upper and lower surfaces of the negative electrode 4 in which the perforations 7 are formed, separators 9 are disposed on the upper and lower surfaces thereof, and the positive electrode layer 3 is opposed to the upper and lower surfaces thereof. The battery body of the lithium ion capacitor of the present embodiment is configured by arranging and laminating the positive electrode 1. Further, the battery body was impregnated with an electrolytic solution in which a lithium salt was dissolved in a non-aqueous solvent and sealed with an exterior container such as an aluminum laminate film, whereby a lithium ion capacitor of the present embodiment was produced.

  In order to lower the potential of the negative electrode and make the lithium ion capacitor usable, it is necessary to dope lithium into the negative electrode. However, in this embodiment, metallic lithium with lithium ion dope applied to the negative electrode surface is attached. Using the foil 8 as a lithium ion supply source, lithium ions were diffused in the electrolytic solution to dope the negative electrode. In some cases, lithium metal oxide such as lithium cobalt oxide is used as a lithium ion supply source in place of metal lithium, and forcible doping is performed by charging from an external power source. The lithium ion supply source other than metallic lithium includes, for example, any one or more of positive electrode active materials capable of occluding and releasing lithium, and if necessary, a conductive material such as a carbon material and A binder such as polyvinylidene fluoride may be included. The positive electrode active material capable of occluding and releasing lithium includes at least lithium-containing phosphates such as olivine-type lithium iron phosphate, lithium composite oxides such as lithium cobaltate, lithium manganate, and lithium nickelate. It is preferable to include at least one lithium-containing transition metal oxide containing one kind of transition metal element, lithium-containing sulfate, or the like, but is not limited thereto.

  The separator separates the negative electrode and the positive electrode and allows lithium ions to pass through while ensuring electrical insulation between the two electrodes. As the material of the separator, for example, polyethylene or polypropylene can be used. Cellulosic paper separators are also suitable.

In the present embodiment, examples of the electrolytic solution include LiPF ₆ , LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiC An electrolyte such as (CF ₃ SO ₂ ) ₃ dissolved in an organic solvent can be used. Examples of organic solvents include ether solvents such as dimethoxyethane and diethyl ether, and ester solvents such as ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (MEC), dimethyl carbonate (DMC), and diethyl carbonate (DEC). Solvent, γ-butyrolactone (GBL), tetrahydrofuran (THF), tetrahydropyran (THP), 1,3-dioxane (DOX), ethyl dimethyl phosphate (EDMP), trimethyl phosphate (TMP), propyl dimethyl phosphate (PDMP) ) And the like, and these can be used alone or in combination of two or more. Furthermore, the electrolyte solution may contain other additives. Examples of combinations of the electrolyte and the electrolyte include LiPF ₆ / EC + DEC, LiBF ₄ / EC + DEC, LiN (CF ₃ SO ₂ ) ₂ / EC + DEC, LiN (C ₂ F ₅ SO ₂ ) ₂ / EC + DEC, LiPF ₆ / EC + PC, LiPF ₆ / EC + GBL, LiBF ₄ / EC + PC, LiBF ₄ / EC + GBL, LiBF ₄ / EDMP, LiBF ₄ / EC + EDMP, LiN (CF ₃ SO ₂ ) ₂ / EC + GBL, LiN (C ₂ F ₅ SO ₂ ) ₂ / EC + G _{(CF 3 SO 2) 2 /} EC + EDMP, LiN (C 2 F 5 SO 2) 2 / EC + but EDMP like, but is not limited thereto. Further, in order to have ionic conductivity even at a high temperature of 100 ° C. or higher, the organic solvent desirably contains a high boiling point solvent such as EC, PC, GBL.

  In the present embodiment, an example of an aluminum laminate film is shown as an exterior container, but other than that, a cylindrical or square container made of a metal such as stainless steel, or a laminate film made of a metal and a resin. It may be a bag-shaped or box-shaped container. The outer packaging container made of this laminate film may be sealed by heat fusion (heat sealing) and can prevent leakage of the electrolytic solution from the inside of the LIC and intrusion of moisture from the outside of the LIC. Although a resin film having heat-fusibility can be used for the seal portion, it is preferable to deposit a metal, coat with metal plating, or laminate a metal foil such as aluminum. When a metal foil is used, it can be used alone if it has a sufficient thickness. However, in order to reduce weight, a metal foil with a thickness of several to several tens of microns is generally used. It is done. Furthermore, it is preferable to laminate a polyethylene or polypropylene film for imparting heat-fusibility on the inner surface and a polyethylene terephthalate or stretched nylon film for improving the strength on the outer surface.

  Various processing methods can be applied to the bag-shaped exterior container. For example, a film cut into a square shape is folded in half and heat-sealed in three directions, and both openings of the film formed into a cylindrical shape are heated. A sealing method and the like can be given. Although the container material may be used after being cut, it may be used after a recess is pressed in a portion corresponding to the battery body of LIC. After heat sealing, an extra portion of the outer container may be cut or subjected to bending.

  The lithium ion capacitor in this embodiment may have a structure in which a positive electrode is opposed to a negative electrode and a separator impregnated with an electrolyte exists between the positive electrode and the negative electrode. A stacked structure in which a plurality of electrodes are stacked, a rolled structure in which strip-shaped electrodes are wound, a folded structure in which strip-shaped electrodes are stacked while being folded, or a composite structure in which these are combined may be used. The ion conductivity between the positive electrode and the negative electrode can be improved by slightly reducing the area of the positive electrode facing the negative electrode (by 1 to 10% by area).

  Further, in the lithium ion capacitor according to the present embodiment, the positive electrode collector terminal and the negative electrode collector terminal electrically connected to the positive electrode and the negative electrode of the battery body are electrically insulated from the outer container and led out to the outside. (Not shown). The positive electrode current collector terminal can be made of aluminum, and the negative electrode current collector terminal can be made of a metal such as nickel or copper or a plated metal such as nickel plated copper. These materials may be conductive materials that exist stably in the LIC. Alternatively, the positive electrode or negative electrode current collecting substrate in a portion where the active material is not applied may be led out to the outside of the outer container to serve as a positive electrode or negative electrode current collecting terminal.

  Hereinafter, in the LIC manufacturing method according to the present embodiment, examples will be described with specific numerical values, and the results of comparing the performance of the obtained LIC with a plurality of comparative examples described later will be described.

Example 1
[Production of negative electrode]
An electrode paste composed of graphite as a negative electrode active material, polyvinylidene fluoride as a binder, and n-methylpyrrolidone as a solvent was mixed and prepared. Next, this electrode paste was coated on both sides of a copper foil having a width of 300 mm and a thickness of 20 μm as a negative electrode current collecting base material to obtain a negative electrode original fabric. This negative electrode original fabric was pressurized at 105 ° C. with a calender roll press to adjust the porosity of the negative electrode layer.

[Negative hole drilling]
A negative electrode raw material is placed between a flat metal mold in which quadrangular pyramid protrusions with a base of 0.4 mm and a height of 0.7 mm are formed at intervals of 0.8 mm, and a metal plate with a smooth surface, The operation of placing an acrylic plate on the substrate and pressing it at a pressure of 0.3 MPa was repeated twice. The direction of pressing in the first time and the second time was shifted by 45 °, and the hole was drilled so that the positions of the holes did not overlap. When the surface (perforated surface) of the negative electrode original fabric after drilling was observed, many square holes each having a side of about 100 μm were formed. Moreover, no hole was observed on the back surface (surface opposite to the perforated surface) of the negative electrode original fabric. For reference, an unnecessary part of the negative electrode raw material after drilling was cut out, dipped in an N-methylpyrrolidone solvent, and the negative electrode layer was peeled and removed. It was 6%. A rectangular negative electrode having a side of 30 mm × 37 mm was cut out from the negative electrode raw material thus prepared, and the negative electrode layer having an end portion of 7 mm in the longitudinal direction was peeled off to obtain a negative electrode current collecting tab. The negative electrode layer was attached to both surfaces of the negative electrode layer by pressing a 30 μm thick lithium metal foil under an inert atmosphere. Thereafter, Ni-plated copper foil was connected to the negative electrode current collecting tab by ultrasonic welding to obtain a negative electrode current collecting terminal.

[Production of positive electrode]
Activated carbon as a positive electrode active material, an acrylic polymer as a binder, and an electrode paste made of water as a solvent were mixed and prepared. Next, this electrode paste was applied and formed on one surface of an aluminum foil having a width of 300 mm and a thickness of 50 μm as a positive electrode current collecting base material to obtain a positive electrode original fabric. This positive electrode original fabric was pressurized with a calender roll press to adjust the porosity of the positive electrode layer. A 29 mm × 36 mm rectangular positive electrode was cut out from the positive electrode raw material, and the active material layer having an end portion of 7 mm in the longitudinal direction was peeled off to obtain a positive electrode current collecting tab.

[Production of cell]
A positive electrode, a separator, a negative electrode, a separator, and a positive electrode were laminated in order of the center so that the electrode layers of the electrodes face each other in order. As the separator, a cellulosic paper separator having a thickness of 40 μm was used. The upper and lower positive electrode current collecting tabs were overlapped and an aluminum foil was connected to the positive electrode current collecting tabs by ultrasonic welding to form a positive electrode current collecting terminal.

The battery body is housed in an aluminum laminate film exterior, and an ethylene carbonate-diethyl carbonate 3: 7 mixed solvent containing 1.2 mol / l LiPF ₆ electrolyte is injected into the exterior, and finally the aluminum laminate exterior is filled. The lithium ion capacitor cell of Example 1 of the present embodiment was manufactured as an outer container. Thereafter, in order to promote lithium insertion into the negative electrode inside the LIC cell, the LIC cell was aged for 3 days in a thermostat at 30 ° C.
Example 2
In Example 2, a positive electrode in which a positive electrode layer including a positive electrode active material layer is formed on one side through a separator on the side opposite to the negative electrode, and a lithium ion supply layer is formed on the other side. is there.

[Production of negative electrode]
It was produced in the same manner as in Example 1.

[Negative electrode processing]
It was produced in the same manner as in Example 1.

[Production of positive electrode]
An electrode paste composed of activated carbon as a positive electrode active material, an acrylic polymer as a binder, and water as a solvent was mixed and prepared. This electrode paste was applied and formed on one surface of a positive electrode current collector base material made of aluminum foil having a width of 300 mm and a thickness of 50 μm to form a positive electrode layer. Next, a lithium supply layer was produced. The lithium ion supply layer was prepared by dispersing lithium cobalt oxide as a lithium ion supply source, acetylene black, and PVDF in NMP, and mixing and adjusting a lithium cobalt oxide paste. This lithium cobaltate paste was applied to one side of an aluminum foil current collecting base material to form a lithium ion supply layer. The positive electrode raw material and the lithium ion supply layer raw material thus prepared were dried at 100 ° C., and then the porosity was adjusted by calendar roll pressing. A rectangular strip of 29 mm × 36 mm is cut out from the positive electrode and the lithium ion supply layer, the positive electrode layer and the lithium ion supply layer at the end 7 mm in the longitudinal direction are peeled off, and the current collecting base is exposed to form a current collecting tab. did. Thereafter, an aluminum foil was connected to these current collecting tabs by ultrasonic welding to form a positive electrode current collecting terminal and a lithium ion supply layer current collecting terminal.

[Production of cell]
The positive electrode, the separator, the negative electrode, the separator, and the lithium ion supply layer were stacked in order with the center aligned so that the positive electrode layer and the lithium ion supply layer face each other. As the separator, a cellulosic paper separator having a thickness of 40 μm was used.

The battery body is housed in an aluminum laminate film exterior, and an ethylene carbonate-diethyl carbonate 3: 7 mixed solvent containing 1.2 mol / l LiPF ₆ electrolyte is injected into the exterior, and finally the aluminum laminate exterior is filled. The lithium ion capacitor cell of Example 1 of the present embodiment was manufactured as an outer container. Thereafter, in order to promote the insertion of lithium ions into the negative electrode, the positive electrode current collector terminal is connected to the positive electrode terminal of the charge / discharge device, and the negative electrode current collector terminal is connected to the negative electrode terminal of the charge / discharge device to 4.0 V at 1 mA. CC-CV charging was performed to dope lithium ions into the negative electrode. Thereafter, the positive electrode terminal and the lithium ion supply layer terminal were short-circuited to complete the lithium ion capacitor cell of Example 2.

  In the present embodiment, the case where the unit in which the positive electrode and the lithium ion supply layer are arranged on both sides of the negative electrode is formed is shown. However, when these units are laminated in multiple layers, one of the aluminum current collector foils is formed. A layer in which a positive electrode active material layer is formed on one surface and a lithium ion supply layer is formed on the other surface may be arranged in multiple layers alternately with a negative electrode through a separator.

Comparative Example 1
In Comparative Example 1, in order to simulate a conventional lithium ion capacitor, an expanded metal is used for the negative electrode current collecting base material.

[Production of negative electrode]
As the negative electrode current collector foil, an expanded metal having a width of 300 mm, a thickness of 30 μm, and an aperture ratio of 55% was used, and an electrode paste produced in the same manner as in Example 1 was applied on both sides. The negative electrode layer having a predetermined thickness was not obtained. Since the negative electrode layer having a predetermined thickness was formed by coating again, the negative electrode original fabric was pressurized at 105 ° C. with a calender roll press to adjust the porosity of the negative electrode layer. A rectangular negative electrode having a side of 30 mm × 37 mm was cut out from the negative electrode raw material, and the active material layer having an end portion of 7 mm in the longitudinal direction was peeled to form a negative electrode current collecting tab. After sufficiently drying this negative electrode in vacuum, it was attached to both surfaces of the negative electrode layer by pressing a lithium metal foil having a thickness of 30 μm in an inert atmosphere. Thereafter, Ni-plated copper foil was connected to the negative electrode current collecting tab by ultrasonic welding to obtain a negative electrode current collecting terminal.

  A positive electrode and a cell were produced in the same manner as in Example 1 except for the production of the negative electrode, and a lithium ion capacitor cell of Comparative Example 1 was produced.

  In the lithium ion capacitor cells of Example 1, Example 2, and Comparative Example 1, a charge / discharge test was performed by changing the discharge current. In the test, CC-CV (constant current-constant voltage) charge was performed up to 4 V at 24 mA, and then the discharge capacity when discharged at each discharge current value shown in Table 1 was measured. The charge / discharge test was performed in an environment of 25 ° C. Table 1 shows the characteristics of the lithium ion capacitor cell in the present embodiment.

  From Table 1, when Example 1 and Example 2 are compared, when both surfaces of the positive electrode are positive electrode layers including a positive electrode active material layer, one surface of the positive electrode is a positive electrode layer including a positive electrode active material layer and the other surface In the case of a lithium ion supply layer containing a lithium transition metal oxide, in Example 2, the lithium ion supply layer is not only supplied to the positive electrode of lithium ions but also charged and discharged between the lithium ion supply layer and the negative electrode. As a result, the discharge capacity obtained is increased.

  Further, in the lithium ion capacitor cell of Comparative Example 1, since the expanded metal is used as the negative electrode current collecting base material, the current collecting base material has a high electric resistance, and a large voltage drop occurs when a large current flows. The capacity could not be obtained. On the other hand, in the lithium ion capacitor cell of Example 1, it can be seen that since the aperture ratio of the current collector foil is low and the electric resistance is low, a high discharge capacity can be obtained even at a high current.

Embodiment 2. FIG.
In the first embodiment, a flat metal mold is used for drilling the negative electrode, but in the second embodiment, drilling of the negative electrode is performed by a roll press. In the present embodiment, the difference between the first embodiment and the first embodiment will be mainly described. The production of the negative electrode, the production of the positive electrode, and the production of the cell were the same as in Example 1 of the first embodiment, and a lithium ion capacitor cell of Example 2 was produced, which was different only in the drilling process described below.

Example 3
[Negative hole drilling]
FIG. 4 is a schematic diagram of a roll press in the present embodiment. As shown in FIG. 4, the negative electrode raw material 15 produced in the same manner as in Example 1 is formed with quadrangular pyramid projections 16 having a base of 0.4 mm and a height of 0.7 mm on the surface of the metallic roll at intervals of 0.8 mm. The negative electrode raw material 15 was punched by passing between the protruding roll 17 and the metallic smooth roll 18 having a smooth surface. When the surface of the negative electrode layer that passed through the protruding roll 17 side after drilling was observed, many square holes with sides of about 80 μm were formed. Moreover, no hole was observed in the negative electrode layer that passed through the metallic smooth roll 18 side. For reference, an unnecessary part of the negative electrode raw material after perforation was cut out, immersed in an N-methylpyrrolidone solvent, and the negative electrode layer was peeled and removed. As a result, the aperture ratio of the negative electrode current collector substrate was 0.12. %Met. A rectangular negative electrode having a side of 30 mm × 37 mm was cut out from the negative electrode raw material thus prepared, and the negative electrode layer having an end portion of 7 mm in the longitudinal direction was peeled off to obtain a negative electrode current collecting tab. The negative electrode layer was attached to both surfaces by pressing a lithium metal foil having a thickness of 30 μm in an inert atmosphere. Thereafter, Ni-plated copper foil was connected to the negative electrode current collecting tab by ultrasonic welding to obtain a negative electrode current collecting terminal.

  The lithium ion capacitor cell of Example 3 was subjected to a charge / discharge test in which the discharge current was changed. In the test, CC-CV (constant current-constant voltage) charge was performed up to 4 V at 24 mA, and then the discharge capacity when discharged at each discharge current value shown in Table 2 was measured. The charge / discharge test was performed in an environment of 25 ° C. Table 2 shows the characteristics of the lithium ion capacitor cell in the present embodiment. Example 1 is also shown for reference.

  From Table 2, the lithium ion capacitor cell of Example 3 also has a low opening ratio of the negative electrode current collector base material and low electrical resistance, as in Example 1, so that a high discharge capacity can be obtained even during large current discharge. Recognize.

  If the negative electrode drilling process using the roll press described in this embodiment is applied to a large-area negative electrode or a long negative electrode required for a lithium ion capacitor having a wound structure described later, the production efficiency High processing can be performed.

Embodiment 3 FIG.
In Example 1 of Embodiment 1, perforations with sides of 120 μm are formed at intervals of 0.8 mm in the negative electrode layer on the perforated surface side, and the perforations extend to the surface of the negative electrode layer on the opposite side of the negative electrode current collector substrate. However, in the third embodiment, lithium ion capacitor cells having different conditions are manufactured. Also in the present embodiment, as in the second embodiment, differences from the first embodiment of the first embodiment will be mainly described. The production of the negative electrode, the production of the positive electrode, and the production of the cell were the same as in Example 1 of the first embodiment, and lithium ion capacitor cells differing only in the drilling process described below were produced.

Example 4
Example 4 is a case where the perforation penetrates to the surface of the negative electrode layer on the opposite side of the negative electrode current collector substrate.

[Negative hole drilling]
The negative electrode raw material after pressing produced in the same manner as in Example 1 was punched with a flat plate press in the same manner as in Example 1. The difference from Example 1 was that pressing was carried out by placing 200 μm thick silicon rubber on the negative electrode original fabric during pressing. When the surface of the negative electrode original fabric after perforation was observed, many square holes of about 300 μm were formed. A large number of holes were formed on the back surface of the negative electrode raw material after drilling, and the negative electrode layer pushed out was deposited around the holes. From the result of cross-sectional observation of the negative electrode original fabric, the unevenness difference due to penetration on the back surface of the negative electrode original fabric was about 40 μm. A rectangular negative electrode having a side of 30 mm × 37 mm was cut out from the negative electrode raw material, and the active material layer having an end portion of 7 mm in the longitudinal direction was peeled to form a negative electrode current collecting tab. After sufficiently drying this negative electrode in vacuum, it was attached to both surfaces of the negative electrode layer by pressing a lithium metal foil having a thickness of 30 μm in an inert atmosphere. Thereafter, Ni-plated copper foil was connected to the negative electrode current collecting tab by ultrasonic welding to obtain a negative electrode current collecting terminal.

  The production of the positive electrode and the production method of the cell were performed in the same manner as in Example 1, and the lithium ion capacitor cell of Example 4 was produced.

Example 5
Example 5 is a case where the aperture ratio of perforation is small.

[Negative hole drilling]
The negative electrode raw material after pressing produced in the same manner as in Example 1 was sandwiched between sheets of polyethylene terephthalate having a thickness of 50 μm, and a large number of quadrangular pyramid projections having a base of 0.4 mm and a height of 0.7 mm were formed. The metal roll having a smooth surface was passed between the metal roll and the surface of the negative electrode raw material. When the surface of the negative electrode original fabric after drilling was observed, many square holes each having a side of about 80 μm were formed. Moreover, no hole was observed on the back surface of the negative electrode original fabric. For reference, an unnecessary part of the negative electrode raw material after drilling was cut out, immersed in an N-methylpyrrolidone solvent, and the negative electrode layer was peeled and removed. As a result, the aperture ratio of the negative electrode current collector substrate was 0.08. %Met. A rectangular negative electrode having a side of 30 mm × 37 mm was cut out from the negative electrode raw material thus prepared, and the negative electrode layer having an end portion of 7 mm in the longitudinal direction was peeled off to obtain a negative electrode current collecting tab. After sufficiently drying this negative electrode in vacuum, it was attached to both surfaces of the negative electrode layer by pressing a lithium metal foil having a thickness of 30 μm in an inert atmosphere. Thereafter, Ni-plated copper foil was connected to the negative electrode current collecting tab by ultrasonic welding to obtain a negative electrode current collecting terminal.

  The production of the positive electrode and the production method of the cell were performed in the same manner as in Example 1, and the lithium ion capacitor cell of Example 5 was produced.

Example 6
Example 6 is a case where the aperture ratio of perforation is large.

[Negative hole drilling]
The negative electrode raw material after pressing produced in the same manner as in Example 1 was punched with a flat plate press in the same manner as in Example 1. The difference from Example 1 is that the operation of pressing at a pressure of 0.3 MPa was repeated 20 times, the pressing direction was slightly shifted each time, and the drilling process was performed so that the positions of the holes did not overlap. . When the surface of the negative electrode original fabric after perforation was observed, many square holes with sides of about 120 μm were formed. Moreover, no hole was observed on the back surface (surface opposite to the perforated surface) of the negative electrode original fabric. For reference, an unnecessary part of the negative electrode raw material after drilling was cut out, immersed in an N-methylpyrrolidone solvent, and the negative electrode layer was peeled and removed. As a result, the aperture ratio of the negative electrode current collector substrate was 5.5. %Met. A rectangular negative electrode having a side of 30 mm × 37 mm was cut out from the negative electrode raw material thus produced, and the active material layer having an end portion of 7 mm in the longitudinal direction was peeled off to obtain a negative electrode current collecting tab. After sufficiently drying this negative electrode in vacuum, it was attached to both surfaces of the negative electrode layer by pressing a lithium metal foil having a thickness of 30 μm in an inert atmosphere. Thereafter, Ni-plated copper foil was connected to the negative electrode current collecting tab by ultrasonic welding to obtain a negative electrode current collecting terminal.

  The production of the positive electrode and the production method of the cell were performed in the same manner as in Example 1, and the lithium ion capacitor cell of Example 6 was produced.

Example 7
Example 7 is a case where the interval between perforations is 5 mm or more.

[Negative hole drilling]
The negative electrode raw material after pressing produced in the same manner as in Example 1 is formed between a metal mold in which quadrangular pyramid projections having a base of 0.4 mm and a height of 0.7 mm are formed at intervals of 7 mm, and a metal plate having a smooth surface. A negative electrode original fabric was placed on the substrate, and an acrylic plate was placed thereon and pressed at a pressure of 0.3 MPa. When the surface (perforated surface) of the negative electrode original fabric after drilling was observed, many square holes each having a side of about 100 μm were formed. Moreover, no hole was observed on the back surface (surface opposite to the perforated surface) of the negative electrode original fabric. For reference, an unnecessary part of the negative electrode raw material after drilling was cut out, dipped in an N-methylpyrrolidone solvent, and the active material layer was peeled and removed. A hole was formed, and the aperture ratio of the negative electrode current collector base material was 0.1%. A rectangular negative electrode having a side of 30 mm × 37 mm was cut out from the negative electrode raw material thus produced, and the active material layer having an end portion of 7 mm in the longitudinal direction was peeled off to obtain a negative electrode current collecting tab. After sufficiently drying this negative electrode in vacuum, it was attached to both surfaces of the active material layer by pressing a lithium metal foil having a thickness of 30 μm in an inert atmosphere. Thereafter, Ni-plated copper foil was connected to the negative electrode current collecting tab by ultrasonic welding to obtain a negative electrode current collecting terminal.

  The production of the positive electrode and the production method of the cell were performed in the same manner as in Example 1, and the lithium ion capacitor cell of Example 7 was produced.

  In the lithium ion capacitor cells of Examples 4 to 7, charge / discharge tests were performed by changing the discharge current. In the test, CC-CV (constant current-constant voltage) charge was performed up to 4 V at 24 mA, and then the discharge capacity when discharged at each discharge current value shown in Table 3 was measured. The charge / discharge test was performed in an environment of 25 ° C. Table 3 shows the characteristics of the lithium ion capacitor cell in the present embodiment. Example 1 is also shown for reference.

  In Table 3, when Example 1 and Example 4 are compared, if the perforation penetrates to the surface of the negative electrode layer on the opposite side of the negative electrode current collecting substrate, the protrusions push the negative electrode surface during the perforation and are extruded. An internal short circuit may occur due to the adhering active material or surface irregularities. Therefore, it is preferable that the perforation does not penetrate to the surface of the negative electrode layer on the opposite side of the negative electrode current collecting substrate. Further, as in the present embodiment, when the shape of the protrusion at the time of drilling is a quadrangular pyramid, when the through hole is formed by drilling, the negative electrode reaction area is reduced compared to the case where the hole does not penetrate, and thus obtained. The capacity is slightly reduced.

  Further, when Example 1 (aperture ratio 0.6%), Example 5 (aperture ratio 0.08%) and Example 6 (aperture ratio 5.5%) were compared, the aperture ratio was 0. When the ratio is less than 0.08%, the dope becomes insufficient, and thus the discharge capacity is reduced. When the hole area ratio is 5.5% or more, the electrode reaction area is reduced, and the discharge capacity is reduced. The rate is preferably about 0.1% to 5% between them.

  Furthermore, when Example 1 and Example 7 are compared, when the interval between the perforations of the negative electrode current collector substrate becomes 7 mm, the doping to the negative electrode layer portion away from the holes becomes insufficient, and the discharge capacity decreases. The perforation interval is preferably 5 mm or less.

Embodiment 4 FIG.
In Embodiments 1 and 2, an example of a lithium ion capacitor having a structure in which a positive electrode, an anode, and the like are simply laminated is shown. However, in Embodiment 4, a lithium ion capacitor having a wound structure is manufactured. Also in the present embodiment, the difference between the first embodiment and the first embodiment will be mainly described.

Example 8
Example 8 is a case where the positive electrode layer containing the positive electrode active material was formed on both surfaces of the positive electrode current collecting base material of the positive electrode.

[Production of negative electrode]
It was manufactured in the same manner as in Example 1 of Embodiment Mode 1.

[Negative electrode processing]
The negative electrode raw material was punched in the same manner as in Example 1 of the first embodiment. A strip-shaped negative electrode of 262 mm × 50 mm was cut from the negative electrode original fabric, and the negative electrode layer having an end portion of 10 mm in the longitudinal direction was peeled only on one side to expose the negative electrode current collecting base material to obtain a negative electrode current collecting tab. After sufficiently drying this negative electrode in vacuum, it was attached to both surfaces of the negative electrode layer by pressing a lithium metal foil having a thickness of 30 μm in an inert atmosphere. Thereafter, Ni-plated copper foil was connected to the negative electrode current collecting tab by ultrasonic welding to obtain a negative electrode current collecting terminal.

[Production of positive electrode]
An electrode paste made of activated carbon as a positive electrode active material, an acrylic polymer as a binder, and water as a solvent was mixed and prepared. Next, this electrode paste was applied and formed on both surfaces of a positive electrode current collector substrate of aluminum foil having a width of 300 mm and a thickness of 50 μm to obtain a positive electrode raw material. This positive electrode original fabric was pressurized with a calender roll press to adjust the porosity of the positive electrode layer. A strip-shaped positive electrode of 248 mm × 46 mm was cut from the positive electrode original fabric, the positive electrode layers on both sides of the end portion of 10 mm in the longitudinal direction were peeled off, and the positive electrode current collecting substrate was exposed to form a positive electrode current collecting tab. Thereafter, an aluminum foil was connected to the positive electrode current collecting tab by ultrasonic welding to form a positive electrode current collecting terminal.

[Production of cell]
FIG. 5 is a schematic cross-sectional view of a wound lithium ion capacitor cell according to Example 8 of the present embodiment. After sufficiently drying each member, the positive electrode current collector terminal 19 and the negative electrode current collector terminal 20 are arranged in the center, and the strip-shaped positive electrode and negative electrode are placed so that the positive electrode layer 3 and the negative electrode layer 6 face each other. Faced across the separator 9, wound around from the end in the long direction and fixed with adhesive tape to produce a wound body 21. This wound body 21 is put in an outer bag made of an aluminum laminate sheet, and an ethylene carbonate-diethyl carbonate 3: 7 mixed solvent containing 1.2 mol / l LiPF ₆ is injected as an electrolytic solution. The opening part of the exterior bag of the aluminum laminate sheet was sealed, and the wound type lithium ion capacitor cell of Example 7 in the present embodiment was produced. Thereafter, in order to promote the insertion of lithium ions into the negative electrode, the positive electrode current collector terminal is connected to the positive electrode terminal of the charge / discharge device, and the negative electrode current collector terminal is connected to the negative electrode terminal of the charge / discharge device. The wound type lithium ion capacitor cell of Example 8 was completed by performing CC-CV charging of lithium ion doping to the negative electrode.

Example 9
Example 9 is a case where a positive electrode layer containing a positive electrode active material is formed on one surface of a positive electrode current collecting base material of a positive electrode, and a lithium supply layer containing a lithium transition metal oxide is formed on the other surface. .

[Production of negative electrode]
It was manufactured in the same manner as in Example 1 of Embodiment Mode 1.

[Negative electrode processing]
It was produced in the same manner as in Example 8.

[Production of positive electrode]
An electrode paste composed of activated carbon as a positive electrode active material, an acrylic polymer as a binder, and water as a solvent was mixed and prepared. This electrode paste was applied and formed on one surface of a positive electrode current collector substrate of aluminum foil having a width of 300 mm and a thickness of 20 μm to form a positive electrode layer. Next, lithium cobaltate as a lithium doping source, acetylene black, and PVDF were dispersed in NMP, and a lithium cobaltate paste was mixed and adjusted. This lithium cobaltate paste was applied and formed on the other surface of the positive electrode current collector substrate to form a lithium ion supply layer. The positive electrode fabric thus produced was dried at 100 ° C. and then roll-pressed to adjust the porosity. A strip-shaped positive electrode of 248 mm × 46 mm is cut from this positive electrode raw material, and the positive electrode layer and the lithium ion supply layer having an end portion of 10 mm in the longitudinal direction are peeled off to expose one side of the positive electrode current collecting substrate to expose the positive electrode current collecting tab. It was. Thereafter, an aluminum foil was connected to the positive electrode current collecting tab by ultrasonic welding to form a positive electrode current collecting terminal.

[Production of cell]
FIG. 6 is a schematic cross-sectional view of a wound lithium ion capacitor cell according to Example 9 of the present embodiment. After each member is sufficiently dried, the positive electrode current collector terminal 19 and the negative electrode current collector terminal 20 are arranged in the center, and the positive electrode layer 3 and the lithium ion supply layer 22 and the negative electrode layer 6 are opposed to each other. The negative electrode was faced across the separator 9 and rolled from the end in the longitudinal direction and fixed with an adhesive tape to produce a wound body. This wound body is put in an outer bag made of an aluminum laminate sheet, and an electrolyte solution containing 1.2 mol / l LiPF ₆ and a mixed solvent of ethylene carbonate-diethyl carbonate 3: 7 is poured into the outer bag. The opening of the laminate sheet outer bag was sealed to complete the wound lithium ion capacitor cell of Example 9 in the present embodiment. Thereafter, in order to promote the insertion of lithium ions into the negative electrode, the lithium ion supply electrode and the positive electrode terminal thereof are connected to the positive electrode terminal of the charge / discharge device, and the negative electrode terminal is connected to the negative electrode terminal of the charge / discharge device. CC-CV charge up to 0 V was performed to dope lithium ions into the negative electrode, and the wound type lithium ion capacitor cell of Example 9 was completed.

Example 10
Example 10 is a case where unevenness is formed on the surface of the negative electrode layer on the side opposite to the perforated side in the drilling process of the negative electrode to face the positive electrode layer.

[Production of negative electrode]
It was manufactured in the same manner as in Example 1 of Embodiment Mode 1.

[Negative electrode processing]
The negative electrode raw material after pressing produced in the same manner as in Example 1 was punched with a flat plate press in the same manner as in Example 1. The difference from Example 1 was that pressing was carried out by placing silicon rubber having a thickness of 70 μm on the negative electrode raw material during pressing. When the surface of the negative electrode original fabric after perforation was observed, many square holes of about 150 μm were formed. Although no holes were observed on the back surface of the negative electrode after the perforation, many irregularities were formed on the surface, and from the results of cross-sectional observation, the irregularity difference was about 30 μm. A strip-shaped negative electrode of 262 mm × 50 mm was cut from the negative electrode original fabric, and the negative electrode layer having an end portion of 10 mm in the longitudinal direction was peeled only on one side to expose the negative electrode current collecting base material to obtain a negative electrode current collecting tab. After sufficiently drying this negative electrode in vacuum, it was attached to both surfaces of the negative electrode layer by pressing a lithium metal foil having a thickness of 30 μm in an inert atmosphere. Thereafter, Ni-plated copper foil was connected to the negative electrode current collecting tab by ultrasonic welding to obtain a negative electrode current collecting terminal.

[Production of positive electrode]
It carried out similarly to Example 9 of this Embodiment. Therefore, in the strip-like positive electrode of this example, the positive electrode layer containing the positive electrode active material is formed on one surface of the positive electrode current collecting base material, and the lithium ion supply layer containing the lithium transition metal oxide is formed on the other surface. It has been done.

[Production of cell]
After each member is sufficiently dried, the strip-shaped positive electrode and negative electrode face each other across the separator so that the positive electrode layer, the lithium ion supply layer, and the negative electrode layer face each other, and are wound around from the end in the long direction. Then, the wound body was prepared by fixing with an adhesive tape. At this time, the perforated surface (negative electrode surface) of the negative electrode was opposed to the lithium ion supply layer, and the surface on which the irregularities were formed (negative electrode back surface) was opposed to the positive electrode layer. This wound body is put in an outer bag made of an aluminum laminate sheet, and an electrolyte solution containing 1.2 mol / l LiPF ₆ and a mixed solvent of ethylene carbonate-diethyl carbonate 3: 7 is poured into the outer bag. The opening part of the exterior bag of a laminate sheet was sealed, and the wound type lithium ion capacitor cell of Example 10 in this Embodiment was produced. Thereafter, in order to promote the insertion of lithium ions into the negative electrode, the lithium ion supply electrode and the positive electrode terminal thereof are connected to the positive electrode terminal of the charge / discharge device, and the negative electrode terminal is connected to the negative electrode terminal of the charge / discharge device. CC-CV charge up to 0V was performed, lithium ions were doped into the negative electrode, and the wound type lithium ion capacitor cell of Example 10 was completed.

Example 11
Example 11 is a case in which irregularities are formed on the surface of the negative electrode layer opposite to the perforated side and face the positive electrode layer in the drilling process of the negative electrode. However, in Example 10, the negative electrode layer with the irregularities formed on the surface was opposed to the positive electrode layer, but in Example 11, the negative electrode layer with the irregularities formed on the surface was opposed to the lithium ion doped layer. Is the case.

  In Example 11, when the wound body for the production of the cell was produced, the perforated surface (negative electrode surface) of the negative electrode was opposed to the positive electrode layer, and the surface on which the irregularities were formed (negative electrode back surface) was the lithium ion doped layer. The wound lithium ion capacitor cell of Example 11 was completed in the same manner as in Example 10 except that it was opposed.

  In the wound type lithium ion capacitor cells of Examples 8 to 11, charge / discharge tests were performed by changing the discharge current. In the test, after performing CC-CV (constant current-constant voltage) charging up to 4 V at 300 mA, the discharge capacity was measured when discharged at each discharge current value shown in Table 4. The charge / discharge test was performed in an environment of 25 ° C. Table 4 shows the characteristics of the wound lithium ion capacitor cell according to the present embodiment.

  In Table 4, Example 8 in which both surfaces of the positive electrode current collecting substrate were constituted by a positive electrode layer containing a positive electrode active material, and one surface of the positive electrode current collecting substrate was a positive electrode layer containing a positive electrode active material, the other Comparing with Example 9 in which the surface is constituted by a lithium ion supply layer containing a lithium transition metal oxide, Example 9 having one side formed by a lithium ion supply layer has a higher discharge capacity at the time of low current discharge. This is because the capacity of lithium cobaltate as a supply source is larger than that of activated carbon which is a positive electrode active material.

  In addition, in the drilling process of the negative electrode, even when irregularities are formed on the surface of the negative electrode layer opposite to the perforated side, when the negative electrode layer having the irregularities is opposed to the positive electrode layer (Example 10) In the case of a flat negative electrode layer (Example 9), a discharge capacity almost equal to that of Example 9 can be obtained. However, when the negative electrode layer having irregularities formed is opposed to the lithium ion supply layer (Example 11), a slightly higher current is obtained. The discharge capacity decreases. This is because when the negative electrode layer with irregularities is facing the lithium ion supply layer, the electrode reaction on the negative electrode layer surface becomes non-uniform as the discharge current increases, and the electrode reaction resistance increases and discharge occurs. It is expected that the capacity has decreased.

  In this embodiment, the lithium ion supply layer is formed using a paste containing lithium cobaltate, but is not limited to lithium cobaltate, and is a material capable of inserting and extracting lithium ions. This embodiment is possible by selecting.

  Further, in the present embodiment, the drilling of the negative electrode is performed by a flat plate press. However, in the case of drilling a larger-area negative electrode or a longer negative electrode, the first embodiment is also used. As explained, drilling can be carried out more efficiently with a roll press of a roll mold.

DESCRIPTION OF SYMBOLS 1 Positive electrode, 2 Positive electrode current collection base material, 3 Positive electrode layer, 4 Negative electrode, 5 Negative electrode current collection base material, 6 Negative electrode layer, 7 Perforation, 8 Metal lithium foil, 9 Separator, 10 Mold, 11 Mold stand, 12 Protrusion , 13 Acrylic plate, 14 Smooth mold, 15 Negative electrode raw material, 16 Protrusion, 17 Protrusion roll, 18 Smooth roll, 19 Positive electrode current collector terminal, 20 Negative electrode current collector terminal, 21 Winding body, 22 Lithium ion supply layer

Claims (10)

Forming a positive electrode layer containing a positive electrode active material capable of adsorbing and desorbing lithium ions or anions on at least one surface of a positive electrode current collector base material to produce a first positive electrode and a second positive electrode, respectively;
A negative electrode layer containing a negative electrode active material capable of occluding and releasing lithium ions is formed on both surfaces of the negative electrode current collector substrate, and the negative electrode current collector substrate is formed from the negative electrode layer formed on one surface of the negative electrode current collector substrate. Forming a perforation reaching the negative electrode layer formed on the other surface through the negative electrode; and
The first positive electrode, the lithium ion source, the negative electrode, the second separator, and the second positive electrode with the positive electrode layer facing the second separator are laminated in order from the surface of the positive electrode layer of the first positive electrode. Manufacturing the battery body,
And a step of impregnating the battery body with an electrolytic solution in which a lithium salt is dissolved in a non-aqueous solvent. Forming a positive electrode layer containing a positive electrode active material capable of adsorbing and desorbing lithium ions or anions on at least one surface of the positive electrode current collector substrate, and forming a positive electrode on at least one surface of the positive electrode current collector substrate; Forming a lithium ion supply layer containing a positive electrode active material capable of occluding and releasing lithium ions, and forming a negative electrode layer containing a negative electrode active material capable of occluding and releasing lithium ions on both sides of the negative electrode current collecting base; A step of forming a negative electrode by forming perforations that penetrate from the negative electrode layer formed on one surface of the negative electrode current collector substrate to the negative electrode layer formed on the other surface through the negative electrode current collector substrate; ,
A battery body in which the first separator, the negative electrode, the second separator, and the second positive electrode with the lithium ion supply layer opposed to the second separator are stacked in order from the surface of the positive electrode layer of the first positive electrode. A step of producing
And a step of impregnating the battery body with an electrolytic solution in which a lithium salt is dissolved in a non-aqueous solvent. Forming a positive electrode layer containing a positive electrode active material capable of adsorbing and desorbing lithium ions or anions on at least one surface of a long positive electrode current collecting base material to produce a first positive electrode and a second positive electrode, respectively; When,
A negative electrode layer containing a negative electrode active material capable of occluding and releasing lithium ions is formed on both sides of a long negative electrode current collecting base material, and the negative electrode layer is formed on one surface of the negative electrode current collecting base material and the negative electrode is formed. Forming a negative electrode by forming a perforation that penetrates the current collector substrate and reaches the negative electrode layer formed on the other surface;
After laminating the first separator, the metallic lithium foil, the negative electrode, the second separator, and the second positive electrode with the positive electrode layer facing the second separator in order from the surface of the positive electrode layer of the first positive electrode Whirling to make a wound body;
And a step of impregnating the wound body with an electrolytic solution in which a lithium salt is dissolved in a non-aqueous solvent. Forming a positive electrode layer containing a positive electrode active material capable of adsorbing and desorbing lithium ions or anions on one surface of a long positive electrode current collecting base material, and producing a first positive electrode;
Forming a second positive electrode by forming a lithium ion supply layer containing a positive electrode active material capable of occluding and releasing lithium ions on one surface of the positive electrode current collector base;
A negative electrode layer containing a negative electrode active material capable of occluding and releasing lithium ions is formed on both sides of a long negative electrode current collecting base material, and the negative electrode layer is formed on one surface of the negative electrode current collecting base material and the negative electrode is formed. Forming a negative electrode by forming a perforation that penetrates the current collector substrate and reaches the negative electrode layer formed on the other surface;
The first positive electrode having the lithium ion supply layer facing the first separator, the metal lithium foil, the negative electrode, the second separator, and the second separator is laminated in order from the surface of the positive electrode layer of the first positive electrode. And then rolling and producing a wound body,
And a step of impregnating the wound body with an electrolytic solution in which a lithium salt is dissolved in a non-aqueous solvent. 5. The method of manufacturing a lithium ion capacitor according to claim 1, wherein the tip of the perforation is inside a negative electrode layer formed on the other surface. 6. In the process of producing the laminate,
5. The method for producing a lithium ion capacitor according to claim 1, wherein a metal lithium foil is sandwiched between the negative electrode and the second separator. 6. In the process of making the negative electrode,
A negative electrode current collecting base material having a negative electrode active material layer formed on both sides is disposed between a first flat plate having a plurality of needle-like protrusions and a second flat plate having a smooth surface, and the first flat plate 5. The method of manufacturing a lithium ion capacitor according to claim 1, wherein the perforations are formed by pressurizing the second flat plate and the plurality of needle-like protrusions. In the process of making the negative electrode,
A negative electrode current collecting base material having a negative electrode active material layer formed on both sides is roll-pressed between a protruding roll having a plurality of needle-like protrusions and a smooth roll having a smooth surface, and perforated by the plurality of needle-like protrusions. The method for producing a lithium ion capacitor according to claim 1, wherein the lithium ion capacitor is formed. 5. The method for producing a lithium ion capacitor according to claim 1, wherein an aperture ratio of perforations of the negative electrode current collecting base material is 0.1% or more and 5% or less. The method for producing a lithium ion capacitor according to any one of claims 1 and 4, wherein the interval between perforations of the negative electrode current collecting base material is 5 mm or less.

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