JP2009253168A - Method of manufacturing electrochemical device electrode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an electrochemical device electrode, which can make an electrode layer into a thin film and provides an electrochemical device with low resistance with successful productivity. <P>SOLUTION: The electrochemical device electrode is manufactured by a manufacturing method comprising steps of: supplying an electrode material on the surface of a collector of which the arithmetic average roughness (Ra) of at least one surface is 1 μm or more; and forming the electrode layer on the collector by pressurizing the collector and the electrode material by a pair of rolls, wherein the forming speed in the step of forming the electrode layer is faster than 10 m/minute. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention may be simply referred to as an electrochemical element electrode (herein referred to simply as an “electrode”) that is suitably used for an electrochemical element such as an electric double layer capacitor or a lithium ion secondary battery, particularly for an electric double layer capacitor. ) Manufacturing method.

  The demand for electrochemical devices such as lithium ion secondary batteries and electric double layer capacitors is rapidly expanding by taking advantage of their small size, light weight, high energy density and the ability to repeatedly charge and discharge. Lithium-ion secondary batteries are used in fields such as mobile phones and notebook personal computers because of their relatively high energy density, and electric double layer capacitors can be charged and discharged rapidly. It is used as. Furthermore, the electric double layer capacitor is expected to be applied as a large power source for electric vehicles. Also, with the aim of achieving both high energy density and charge / discharge speed, a hybrid capacitor that uses a Faraday reaction electrode for one of the positive electrode and the negative electrode and a non-Faraday reaction electrode for the other has been developed. In addition, redox capacitors that utilize the oxidation-reduction reaction (pseudo electric double layer capacitance) on the surface of metal oxides or conductive polymers are also attracting attention due to their large capacity. With the expansion and development of applications, these electrochemical elements are required to further improve characteristics such as low resistance, high capacity, and improved mechanical characteristics. Under such circumstances, in order to improve the performance of the electrochemical device, various improvements have been made on the method of forming the electrochemical device electrode.

  An electrochemical element electrode can be obtained by, for example, applying an electrode material slurry containing an electrode active material or the like on a current collector and drying it. However, this manufacturing method has a problem that a long time is required for the drying process, the productivity is poor, and the electrode cost is increased.

  As a solution for improving productivity and reducing electrode cost, Patent Document 1 introduces a method for producing an electrochemical element electrode using a quantitative feeder and a pair of press rolls or belts arranged substantially horizontally. Yes. According to this document, a metal such as aluminum or platinum can be used as a current collector and molding can be performed at a speed of 1 to 20 m / min. However, it is difficult to produce a thin film electrode by this method, and there is a limit to reducing the resistance.

JP 2007-005747 A

  An object of the present invention is to provide a method for producing a low-resistance and low-cost electrochemical element electrode by using a current collector having a surface arithmetic average roughness of 1 μm or more.

  As a result of intensive studies in view of the above problems, the present inventors have found that the current collector used in the method disclosed in Patent Document 1 has a surface roughness as small as 0.5 μm in arithmetic mean roughness (Ra). The current collector was poorly applied, and it was found that it was difficult to produce a thin film electrode using the current collector. And when the collector of specific surface roughness was used, it discovered that thin film formation was easy by roll forming and the electrochemical element electrode of low resistance was obtained. Based on these findings, the inventors have completed the present invention.

  Thus, according to the present invention, a step of supplying an electrode material onto the surface of a current collector having an arithmetic average roughness (Ra) of at least one surface of 1 μm or more, and a pair of the current collector and the electrode material There is provided a method for producing an electrochemical element electrode comprising a step of forming an electrode layer on a current collector by pressurizing with a roll, and a forming speed in the step of forming the electrode layer being higher than 10 m / min. Provided.

  ADVANTAGE OF THE INVENTION According to this invention, the electrode layer can be thinned and the electrochemical element electrode which gives a low resistance electrochemical element can be efficiently manufactured in large quantities. Since the electrochemical element electrode obtained by the production method of the present invention has low resistance and low cost, it is suitably used for various applications such as electric double layer capacitors and secondary batteries.

  The electrode material used in the present invention is used for obtaining an electrochemical element electrode. Specifically, an electrode active material and a binder are essential components, and a conductive material, a dispersion material, and Other additives and the like can be contained.

  The electrode active material is a material that transfers electrons within the electrode, and specifically includes an active material for a lithium ion secondary battery and an active material for an electric double layer capacitor.

Examples of the active material for a lithium ion secondary battery include a positive electrode and a negative electrode. As an electrode active material for a positive electrode of a lithium ion secondary battery, lithium-containing composite metal oxides such as LiCoO ₂ , LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , LiFePO ₄ , LiFeVO ₄ ; TiS ₂ , TiS ₃ , non Transition metal sulfides such as crystalline MoS ₃ ; transition metal oxides such as Cu ₂ V ₂ O ₃ , amorphous V ₂ O · P ₂ O ₅ , MoO ₃ , V ₂ O ₅ , V ₆ O ₁₃ ; Illustrated. Furthermore, conductive polymers such as polyacetylene and poly-p-phenylene are listed. Examples of the electrode active material for the negative electrode of the lithium ion secondary battery include carbonaceous materials such as amorphous carbon, graphite, natural graphite, mesocarbon microbeads (MCMB), and pitch-based carbon fibers; high conductivity such as polyacene Examples include molecules.

The electrode active material used for the electrode of the lithium ion secondary battery is preferably sized into spherical particles. When the shape of the particles is spherical, a higher density electrode can be formed during electrode molding. The weight average particle size distribution is preferably a mixture of fine particles of about 1 μm and relatively large particles of 3 to 8 μm, or particles having a broad particle size distribution of 0.5 to 8 μm. Particles having a particle size of 50 μm or more are preferably used after being removed by sieving or the like. The tap density defined by ASTM D4164 of the electrode active material is not particularly limited, but those having a positive electrode of 2 g / cm ³ or more and those of a negative electrode of 0.6 g / cm ³ or more are preferably used.

  As an electrode active material for an electric double layer capacitor, an allotrope of carbon is usually used. Specific examples of the allotrope of carbon include activated carbon, polyacene, carbon whisker, and graphite, and these powders or fibers can be used. A preferable electrode active material for the electric double layer capacitor is activated carbon, and specific examples include phenol-based, rayon-based, acrylic-based, pitch-based, and coconut shell-based activated carbon.

The specific surface area of the electrode active material for an electric double layer capacitor, ^{30 m} 2 / g or more, preferably preferably 500~5,000m ² / g, more preferably 1,000~3,000m ² / g.

  The weight average particle diameter of the electrode active material for the electric double layer capacitor is preferably 0.1 to 100 μm, preferably 1 to 50 μm, more preferably 5 to 20 μm. When an active material having a weight average particle diameter in this range is used, the electric double layer capacitor electrode can be easily thinned and the capacitance can be increased.

  These electrode active materials can be used individually or in combination of 2 or more types according to the kind of electrochemical element.

  The binder is a compound that can bind an electrode active material, a conductive material, and the like. For example, polymer compounds such as fluorine-based polymers, diene-based polymers, acrylate-based polymers, polyimides, polyamides, and polyurethanes are preferable, and fluorine-based polymers, diene-based polymers, and acrylate-based polymers are preferable. It is done.

  The fluorine-based polymer is a polymer containing a monomer unit containing a fluorine atom. The ratio of the monomer unit containing fluorine in the fluoropolymer is usually 50% by weight or more. Specific examples of the fluorine-based polymer include fluorine resins such as polytetrafluoroethylene and polyvinylidene fluoride, and polytetrafluoroethylene is preferable.

  The diene polymer is a homopolymer of a conjugated diene or a copolymer obtained by polymerizing a monomer mixture containing a conjugated diene, or a hydrogenated product thereof. The proportion of the conjugated diene in the monomer mixture is usually 40% by weight or more, preferably 50% by weight or more, more preferably 60% by weight or more. Specific examples of the diene polymer include conjugated diene homopolymers such as polybutadiene and polyisoprene; aromatic vinyl / conjugated diene copolymers such as carboxy-modified styrene / butadiene copolymer (SBR); Examples include vinyl cyanide / conjugated diene copolymers such as acrylonitrile / butadiene copolymer (NBR); hydrogenated SBR, hydrogenated NBR, and the like.

  The acrylate polymer is a copolymer obtained by polymerizing a homopolymer of acrylic acid ester and / or methacrylic acid ester or a monomer mixture containing them. The ratio of acrylic acid ester and / or methacrylic acid ester in the monomer mixture is usually 40% by weight or more, preferably 50% by weight or more, more preferably 60% by weight or more. Specific examples of the acrylate polymer include 2-ethylhexyl acrylate / methacrylic acid / acrylonitrile / ethylene glycol dimethacrylate copolymer, 2-ethylhexyl acrylate / methacrylic acid / methacrylonitrile / diethylene glycol dimethacrylate copolymer, acrylic Crosslinking of 2-ethylhexyl acid / styrene / methacrylic acid / ethylene glycol dimethacrylate copolymer, butyl acrylate / acrylonitrile / diethylene glycol dimethacrylate copolymer, and butyl acrylate / acrylic acid / trimethylolpropane trimethacrylate copolymer Type acrylate polymer; ethylene / methyl acrylate copolymer, ethylene / methyl methacrylate copolymer, ethylene / ethyl acrylate copolymer, and A copolymer of ethylene and acrylic acid (or methacrylic acid) such as an ethylene / ethyl methacrylate copolymer; a radical polymerizable monomer in the copolymer of ethylene and acrylic acid (or methacrylic acid) Grafted graft polymers; and the like. In addition, as a radically polymerizable monomer used for the said graft polymer, methyl methacrylate, acrylonitrile, methacrylic acid etc. are mentioned, for example. In addition, a copolymer of ethylene and acrylic acid (or methacrylic acid) such as an ethylene / acrylic acid copolymer and an ethylene / methacrylic acid copolymer can be used as a binder.

  The binder is not particularly limited depending on its shape, but has good binding properties, and can be prevented from being deteriorated due to a decrease in the capacitance of the produced electrode or repeated charge / discharge, and therefore is in the form of particles. Is preferred. Examples of the particulate binder include those in which particles of a dispersion-type binder such as latex are dispersed in water, and powders obtained by drying such a dispersion.

  The number average particle size of the particulate binder is not particularly limited, but is usually 0.0001 to 100 μm, preferably 0.001 to 10 μm, more preferably 0.01 to 1 μm. When the number average particle diameter of the binder is within this range, an excellent binding force can be imparted to the electrode layer even when a small amount of the binder is used. Here, the number average particle diameter is a number average particle diameter calculated as an arithmetic average value obtained by measuring the diameter of 100 binder particles randomly selected in a transmission electron micrograph. The shape of the particles can be either spherical or irregular.

  These binders can be used alone or in combination of two or more. The amount of the binder used is usually 0.1 to 50 parts by weight, preferably 0.5 to 20 parts by weight, and more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the electrode active material. is there.

  The electrode material used for the positive electrode of the lithium ion secondary battery or the electrode of the electric double layer capacitor preferably contains a conductive material. The conductive material is made of an allotrope of particulate carbon that has conductivity and does not have pores that can form an electric double layer, and improves the conductivity of the electrochemical element electrode. Specific examples of the conductive material include conductive carbon black such as furnace black, acetylene black, and ketjen black (registered trademark of Akzo Nobel Chemicals Bethloten Fennot Shap); graphite such as natural graphite and artificial graphite; Can be mentioned. Among these, conductive carbon black is preferable, and acetylene black and furnace black are more preferable.

  The weight average particle diameter of the conductive material is preferably smaller than the weight average particle diameter of the electrode active material, and is usually in the range of 0.001 to 10 μm, preferably 0.05 to 5 μm, more preferably 0.01 to 1 μm. is there. When the particle size of the conductive material is within this range, high conductivity can be obtained with a smaller amount of use.

  These conductive materials can be used alone or in combination of two or more.

  The amount of the conductive material is usually 0.1 to 50 parts by weight, preferably 0.5 to 15 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the electrode active material. When an electrode having an amount of the conductive material within this range is used, the capacity of the electrochemical element can be increased and the internal resistance can be decreased.

  In addition, the electrode material preferably contains a dispersing agent. The dispersing material is used by being dissolved in a slurry solvent, and further has an action of uniformly dispersing the electrode active material, the conductive material and the like in the solvent. For example, cellulosic polymers such as carboxymethyl cellulose, methyl cellulose, ethyl cellulose, hydroxypropyl cellulose, and ammonium salts or alkali metal salts thereof; polyacrylic acid (or methacrylic acid) salts such as sodium polyacrylic acid (or methacrylic acid); polyvinyl Examples include alcohol, modified polyvinyl alcohol, polyethylene oxide; polyvinyl pyrrolidone, polycarboxylic acid, oxidized starch, phosphate starch, casein, various modified starches, chitin, and chitosan derivatives. These dispersing agents can be used alone or in combination of two or more. Among these, a cellulose polymer is preferable, and carboxymethyl cellulose or an ammonium salt or an alkali metal salt thereof is particularly preferable.

  These dispersing agents can be used alone or in combination of two or more. The amount of the dispersing agent used is not particularly limited, but is usually 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, more preferably 0.8 to 100 parts by weight of the electrode active material. It is in the range of ˜2 parts by weight. By using the dispersing material, it is possible to suppress sedimentation and aggregation of the solid content in the slurry. Moreover, since the clogging of the atomizer at the time of spray drying can be prevented, spray drying can be performed stably and continuously.

  Examples of other additives include a surfactant. Examples of the surfactant include amphoteric surfactants such as anionic, cationic, nonionic, and nonionic anions. Among them, anionic or nonionic surfactants that are easily thermally decomposed are preferable. These additives can be used alone or in combination of two or more.

  The amount of the surfactant is not particularly limited, but is 0 to 50 parts by weight, preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the electrode active material. It is a range.

  The electrode material used in the present invention contains the above-described electrode active material and binder as essential components, and contains a conductive material, a dispersing material, and other additives as necessary. A suitably used electrode material is in the form of particles containing the above components (hereinafter sometimes referred to as composite particles). The composite particles usually contain at least an electrode active material and a binder, and are configured by binding the electrode active material and a conductive material with a binder.

  The weight average particle diameter of the composite particles used in the present invention is usually in the range of 0.1 to 1,000 μm, preferably 5 to 500 μm, more preferably 10 to 100 μm.

  The composite particles suitable for the present invention have a particle size displacement rate of usually 5 to 70%, preferably 20 to 50% when compressed to a maximum load of 9.8 mN at a load speed of 0.9 mN / sec by a micro compression tester. is there. The particle size displacement rate is the ratio (= ΔD / D0 × 100) of the amount of particle size reduction (ΔD = D0−D1) due to compression to the particle size D0 before compression of the composite particles. In addition, D1 is a value which changes according to a load amount with a particle size when applying a load.

  In addition, the composite particles suitably used in the present invention preferably have a change in particle size displacement rate per unit second when compressed to a maximum load of 9.8 mN at a load speed of 0.9 mN / sec using a micro compression tester. It is 25% or less, more preferably 10% or less, and particularly preferably 7% or less. The change amount of the particle size displacement rate per unit second is the change amount per unit second of the particle size change rate when the load increases at a load speed of 0.9 mN / sec. The particle size displacement rate when compressed to a maximum load of 9.8 mN measured by a micro-compression tester is a numerical value necessary to show the shape maintaining force of the composite particles. If the particle size displacement rate is too small, the composite particles are hardly deformed even by pressurization, so that the contact area between the particles is small and the conductivity is not increased. On the other hand, if the particle size displacement rate is too large, the composite particles are crushed, the network formed by the conductive material and the electrode active material formed in the composite particles is broken, and the conductivity is lowered. Further, the change amount of the particle size displacement rate per unit second is an index for determining the presence or absence of crushing. When crushing occurs, the particle size decreases rapidly, so that the amount of change in the particle size displacement rate per second exceeds 25%. By crushing, the network formed by the conductive material and the electrode active material formed in the composite particles is broken, and the conductivity is lowered. Since the composite particle having a particle size displacement rate of 5 to 70% when compressed to a maximum load of 9.8 mN has appropriate softness, the contact area between the particles is large. And since it is not crushed, the network of a conductive material and an electrode active material is maintained.

  These composite particles can be used alone or in combination of two or more.

  The current collector used in the present invention is an electrode substrate having a current collecting function. As the material, for example, metal, carbon, conductive polymer, and the like can be used, and metal is preferably used. As the metal, aluminum, platinum, nickel, tantalum, titanium, stainless steel, copper, and other alloys are usually used. Among these, it is preferable to use aluminum or an aluminum alloy in terms of conductivity and voltage resistance.

  The current collector used in the present invention has an arithmetic average roughness (Ra) of at least one surface of 1 μm or more, and can improve moldability and adhesion, and is particularly preferably 1 μm or more and 2 μm or less. The difference between the Ra on the front surface and the back surface of the current collector is usually 3 μm or less, and preferably 1 μm or less because variations in electrode layer thickness on both surfaces can be reduced.

  The current collector used in the present invention is usually in the form of a sheet, and the thickness thereof is appropriately selected according to the purpose of use, but preferably 10 to 10 from the viewpoint of achieving both high strength and low resistance. The thickness is 100 μm, more preferably 50 to 100 μm.

  In this invention, the said electrode material is supplied on this surface on the electrical power collector which has said surface roughness. The feeder used in the step of supplying the electrode material is not particularly limited, but is preferably a quantitative feeder capable of supplying composite particles quantitatively. Here, being able to supply quantitatively means that the electrode material is continuously supplied using such a feeder, the supply amount is measured a plurality of times at regular intervals, and the average value m of the measured values and the standard deviation σm are obtained. It means that the CV value (= σm / m × 100) is 4 or less. The quantitative feeder used in the present invention preferably has a CV value of 2 or less. Specific examples of the quantitative feeder include a gravity feeder such as a table feeder and a rotary feeder, and a mechanical force feeder such as a screw feeder and a belt feeder. Of these, the rotary feeder is preferred.

  Next, the current collector and the supplied electrode material are pressurized with a pair of rolls to form an electrode layer on the current collector. In this step, the electrode material heated as necessary is formed into a sheet-like electrode layer by a pair of rolls. The temperature of the supplied composite particles is preferably 40 to 160 ° C, more preferably 70 to 140 ° C. When an electrode material in this temperature range is used, there is no slip of the electrode material on the surface of the press roll, and the electrode material is continuously and uniformly supplied to the press roll. An electrochemical element electrode sheet with small variations can be obtained.

  The molding temperature is usually 0 to 200 ° C., which is higher than the melting point or glass transition temperature of the binder (when the binder has both the melting point and the glass transition temperature, the same applies hereinafter). It is preferable that the melting point or glass transition temperature is 20 ° C. or higher.

  The forming speed in the case of using a roll can be adjusted by the rotational speed of the roll, and is faster than 10 m / min, preferably 35 to 70 m / min. Moreover, the press linear pressure between the rolls for a press is 0.2-30 kN / cm normally, Preferably it is 0.5-10 kN / cm.

  In the production method of the present invention, the arrangement of the pair of rolls is not particularly limited, but is preferably arranged substantially horizontally or substantially vertically. When arranged substantially horizontally, the porous current collector is continuously supplied between a pair of rolls, and an electrode material is supplied to at least one of the rolls, so that the gap between the porous current collector and the rolls is increased. An electrode material is supplied to the electrode layer, and an electrode layer can be formed by pressurization. In the case of disposing substantially vertically, the porous current collector is conveyed in the horizontal direction, an electrode material is supplied onto the current collector, and an electrode material layer is formed. After the supplied electrode material layer is leveled with a blade or the like as necessary, the current collector is supplied between a pair of rolls, and the electrode layer can be formed by pressurization. In this case, the thickness of the electrode material layer supplied between the pair of rolls is a value represented by (roll gap between the pair of rolls) / (current collector thickness + electrode material layer thickness). From the viewpoint of excellent moldability, it is usually from 0.01 to 1, and preferably from 0.1 to 0.5.

  In order to eliminate the variation in the thickness of the molded body, increase the density, and increase the capacity, further pressurization may be performed as necessary. The post-pressing method is generally a press process using a roll. In the roll press process, two cylindrical rolls are arranged in parallel at a narrow interval in the vertical direction, and each is rotated in the opposite direction. The temperature of the roll may be adjusted by heating or cooling.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated further more concretely, this invention is not restrict | limited to the following Example. Parts and% are based on weight unless otherwise specified.

(Measurement of arithmetic mean roughness (Ra) of current collector surface)
The arithmetic mean roughness (Ra) of the current collector surface was drawn with a roughness curve in the range of 5 mm × 5 mm using a nano-scale hybrid microscope (VN-8000) manufactured by Keyence Corporation (a porous current collector). ) Is determined by the calculation method of the following formula. L is the measurement length (5 mm), and x is the deviation from the average line to the measurement curve.

(Measurement of electrode layer thickness)
The electrode layer thickness is measured using an eddy current displacement sensor (sensor head unit EX-110V, amplifier unit unit EX-V02: manufactured by Keyence Corporation) after forming electrode layers on both sides of the current collector. The thickness of each electrode layer is measured at intervals of 2 cm, and the average value thereof is taken as the thickness of the electrode layer.

(Measurement of internal resistance)
The electrochemical capacitor starts to be charged with a constant current of 600 mA. When a predetermined charging voltage is reached, the voltage is maintained to be constant voltage charging, and charging is completed when the constant voltage charging is performed for 5 minutes. Next, immediately after the end of charging, discharging is performed at a constant current of 15 mA until reaching 0V. This charge / discharge operation is performed for 3 cycles, and is calculated from the relationship of R = ΔV / I from the voltage 0.1 seconds after the discharge of the third cycle.

Example 1
100 parts of an electrode active material (activated carbon with a specific surface area of 2000 m ² / g and a weight average particle size of 5 μm), 5 parts of a conductive material (acetylene black “Denka black powder”; manufactured by Denki Kagaku Kogyo Co., Ltd.), a dispersion-type binder (40% aqueous dispersion of a cross-linked acrylate polymer having a number average particle size of 0.15 μm and a glass transition temperature of −40 ° C .: “AD211”; manufactured by Nippon Zeon Co., Ltd.) 7.5 parts, Dispersant (carboxymethylcellulose Of 1.5% aqueous solution “DN-800H” (manufactured by Daicel Chemical Industries, Ltd.) and 231.8 parts of ion-exchanged water K. The mixture is stirred and mixed with a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to obtain a slurry having a solid content of 25%. Next, the slurry is spray-dried with hot air at 150 ° C. using a spray dryer (with a pin type atomizer manufactured by Okawara Chemical Industries Co., Ltd.) to obtain spherical composite particles having a weight average particle size of 60 μm.

Using a fixed feeder (Nikka Co., Ltd., Nikka Spray K-V) at a feeding speed of 70 g / min for each feeder, a roll for press (roll) The temperature is 120 ° C. and the press linear pressure is 4 kN / cm). An etched aluminum foil with a thickness of 50 μm and Ra = 2.5 μm is inserted between the press rolls, and the composite particles supplied from the quantitative feeder are attached to both sides of the etched aluminum foil, and pressed at a molding speed of 15 m / min. An electrochemical element electrode having an average single-side thickness of 280 μm and an average single-side density of 0.50 g / cm ³ is obtained by molding.

(Preparation of measurement cell)
The above-described electrochemical device electrode is cut out so that the current collector portion where the electrode layer is not formed is 2 cm long × 2 cm wide, and the portion where the electrode layer is formed is 5 cm × 5 cm wide. A tab electrode made of aluminum having a length of 7 cm, a width of 1 cm, and a thickness of 0.01 cm is ultrasonically welded to the uncoated portion to produce a measurement electrode. As the measurement electrodes, 10 sets of positive electrodes and 11 sets of negative electrodes are prepared and dried at 160 ° C. for 40 minutes. Using a cellulose / rayon mixed nonwoven fabric having a thickness of 35 μm as a separator, the terminal welds of the positive electrode current collector and the negative electrode current collector are arranged on opposite sides, and the opposing surfaces of the positive electrode and the negative electrode are 20 layers. In addition, lamination is performed so that the outermost electrode of the laminated electrodes becomes a negative electrode. The uppermost part and the lowermost part are provided with separators, and four sides are taped, and the terminal welded part (10 sheets) of the positive electrode current collector and the terminal welded part (11 sheets) of the negative electrode current collector are ultrasonically welded.

  After covering the laminated electrode with an exterior laminate film and fusing three sides, a solution prepared by dissolving tetraethylammonium borofluoride at a concentration of 1.4 mol / liter in propylene carbonate as an electrolytic solution was vacuum impregnated, and then the remaining side was melted. A film type capacitor is produced. Each characteristic is measured about the film type capacitor obtained. The results are shown in Table 1.

Example 2
An electrochemical element electrode and a film type capacitor are produced in the same manner as in Example 1 except that an etched aluminum foil having a thickness of 50 μm and Ra = 1.5 μm is used as a current collector.

Example 3
An electrochemical element electrode and a film type capacitor are produced in the same manner as in Example 2 except that the molding speed is 40 m / min.

Comparative Example 1
An electrochemical element electrode and a film type capacitor are produced in the same manner as in Example 1 except that an etched aluminum foil having a thickness of 50 μm and Ra = 0.5 μm is used as the current collector.

Comparative Example 2
When an electrochemical device electrode was manufactured in the same manner as in Example 3 except that an etched aluminum foil with a thickness of 50 μm and Ra = 0.5 μm was used as the current collector, the granulated particles were applied to the current collector. However, the composite particles do not penetrate into the gap between the rolls, and the electrode cannot be formed. The results are shown in Table 1.

  In the manufacturing method of the comparative example using a current collector having an arithmetic average roughness (Ra) of less than 1 μm, a non-formed part is generated and a uniform electrode cannot be obtained, or if the forming speed is increased, the forming itself is impossible. become. On the other hand, in the manufacturing method of the example using the current collector with Ra of 1 μm or more, the problem as in the comparative example does not occur, the electrode can be manufactured stably, and the molding speed is increased as in the examples 2 and 3. By doing so, a thin film electrode can be obtained and the resistance can be reduced.

Claims (2)

Supplying an electrode material onto the surface of the current collector having an arithmetic average roughness (Ra) of at least 1 μm of at least one surface;
And forming the electrode layer on the current collector by pressurizing the current collector and the electrode material with a pair of rolls,
And the manufacturing method of the electrochemical element electrode whose forming speed in the process of forming the said electrode layer is a speed higher than 10 m / min. The manufacturing method according to claim 1, wherein the electrochemical element electrode has a thickness of 300 μm or less.