JP3835851B2 - Manufacturing method of integrated electrode for electric double layer capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the productivity of a laminated electric double-layer capacitor by producing an integrated electrode composed of a metal-made collecting electrode and polar electrode used as a positive and negative electrodes of this capacitor with the less number of steps than that of the prior art. SOLUTION: An active carbon powder is kneaded with at least a binder added thereto to prepare a kneaded material for forming a polar electrode. This material is thrown by specified amount in a die 4 to form a first kneaded material layer 1, a mesh-like metalmade collecting electrode 11 is laid thereon, that kneaded material is thrown by a specified amt. thereon to form a second kneaded material layer 2. The layers are compression-formed by a press 3 to bury the collecting electrode 11 in the polar layer with collecting electrode leads 11a led outside to form an integrated electrode.

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a component of a large-capacity multilayer electric double layer capacitor having a capacitance of about 1000 to 10,000 F that can be used as a power source for electric bicycles, electric tools, etc., and is used as a positive electrode and a negative electrode, and is a metal collector electrode The present invention relates to a method for producing an integrated electrode for an electric double layer capacitor, in which an integrated electrode formed by integrating a polarizable electrode and a polarizable electrode can be manufactured with a smaller number of processes than in the past.
[0002]
[Prior art]
Conventionally, as a large-capacity electric double layer capacitor that can be used as a power source for temporarily supplying large energy, a positive electrode comprising a positive electrode metal collecting electrode and a positive charge storage polarizable electrode, and a negative electrode metal A negative electrode consisting of a collector electrode and a polarizable electrode for accumulating negative charge is alternately stacked with a separator in between, and charges are accumulated in an electric double layer formed at the interface between the electrolyte and the polarizable electrode. A multilayer electric double layer capacitor that utilizes the above has been proposed. FIG. 5 is a perspective view showing a positive electrode that is an integrated electrode manufactured by a conventional method, and FIG. 6 is a partial cutaway view of the entire configuration of the multilayer electric double layer capacitor incorporating the integrated electrode shown in FIG. It is a perspective view shown missing.
[0003]
As shown in FIG. 5, a flat plate-like positive electrode 50 has a rectangular portion formed by sheeting activated carbon powder on both sides of a rectangular metal collecting electrode 52 having a strip-shaped lead portion 52a formed in a part thereof. The polar electrodes 53 and 53 'are bonded together by heat fusion using a conductive film or the like, and the metal collector electrode 52 and the polarizable electrodes 53 and 53' are integrated as an integrated electrode. Here, each polarizable electrode 53, 53 'kneads activated carbon powder for accumulating electric charge and PTFE (polytetrafluoroethylene) as a binder (binder), and the kneaded product is pressed by a press or a rolling roll. Etc. are used for molding.
[0004]
Each of the polarizable electrodes 53 and 53 'has a thickness of about 0.1 to 2.0 mm, and the metal collector electrode 52 for collecting charges from the polarizable electrodes 53 and 53' has a thickness of about 0.1 to 2.0 mm. It is about 5-300 micrometers, Comprising: It consists of aluminum or stainless steel. The lead portion 52a of the metal collector electrode 52 is for establishing electrical continuity with an external terminal. The negative electrode 51 also has the same structure as the positive electrode 50 and is configured as an integrated electrode.
[0005]
As shown in FIG. 6, the positive electrodes 50 and the negative electrodes 51 are alternately stacked with separators 54 having the same outer dimensions as the polarizable electrodes 53 and 53 ′. The separator 54 is made of a porous material having ion permeability and electrical insulation, and for example, a polypropylene fiber nonwoven fabric is used. Then, as shown in FIG. 6, a large number of lead portions 52 a for positive electrodes are connected to positive electrode external terminals 56 provided on an electrically insulating lid body 58 via lead bodies 55. Similarly, each negative electrode lead portion 52a 'is connected to the negative electrode external terminal 56'. Next, the electrode laminate in which the electrodes 50 and 51 are overlapped is accommodated in the rectangular outer case 57, and then the lid 58 is attached and sealed.
[0006]
[Problems to be solved by the invention]
However, in the conventional method of manufacturing the integrated electrode 50 in which the metal collecting electrode 52 and the polarizable electrodes 53 and 53 ′ are integrated, the polarizable electrodes 53 and 53 ′ are previously formed by a press or roll rolling. And a step of fixing and integrating each of the obtained polarizable electrodes 53 and 53 'to the metal collector electrode 52, and fixing and integration with the metal collector electrode and polarizability. By making it possible to simultaneously mold the electrode itself, there is a room for reducing the number of manufacturing steps, thereby improving the productivity of the electric double layer capacitor.
[0007]
In addition, since the polarizable electrodes 53 and 53 'are bonded to the metal collector electrode 52 by heat fusion using a conductive film and fixed and integrated, the electrodes are not securely and firmly fixed to each other. was there. For this reason, an electric double layer capacitor incorporating such an integrated electrode has a large internal resistance value, resulting in a large resistance loss during charging / discharging, and when mounted on an electric bicycle or electric vehicle. There is a problem that the integrated electrode is easily peeled off by mechanical vibration or impact.
[0008]
Therefore, the present invention can produce an integrated electrode for a multilayer electric double layer capacitor in which a metal collecting electrode and a polarizable electrode are integrated with a smaller number of processes than before, thereby producing an electric double layer capacitor. In addition, the metal collector electrode and the polarizable electrode can be firmly and tightly integrated with each other. By incorporating this into an electric double layer capacitor, the internal resistance value is small, An object of the present invention is to provide a method for manufacturing an integrated electrode for an electric double layer capacitor, which can obtain an electric double layer capacitor that is resistant to mechanical vibration and impact.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a method for manufacturing an integrated electrode for an electric double layer capacitor according to the present invention is used as a positive electrode and a negative electrode of a multilayer electric double layer capacitor, and a metal collector electrode, a polarizable electrode, When producing an integrated electrode made by integrating a mixture of activated carbon and at least a binder, kneaded material for forming a polarizable electrode is prepared, and a predetermined amount of the kneaded material is put into a mold. Then, a metal collecting electrode having a mesh shape is placed thereon, and a predetermined amount of the kneaded material is placed thereon to form a second kneaded material layer. The metal collector electrode is embedded in the polarizable electrode in a state where the collector electrode lead portion is pulled out by performing pressure molding with a pressurizer, and the metal collector electrode and the polarizable electrode are integrated. It is characterized by the fact that
[0010]
In the manufacturing method according to the present invention configured as described above, the polarizable electrode itself is molded and the polarizable electrode and the metal collector electrode are fixed and integrated only by performing pressure molding once with a pressurizer. The number of manufacturing processes can be reduced as compared with the conventional method.
[0011]
In addition, as a metal collector electrode, an aluminum net foil, an aluminum punched foil obtained by punching an aluminum foil such as a punching metal, an aluminum expanded foil obtained by subjecting an aluminum foil to an expanded process, a metal foil or A metal collector electrode made of a mesh-like material in which a large number of small holes are formed in a metal plate is used. For this reason, by performing pressure molding, the kneaded material for forming the polarizable electrode bites into the numerous small holes of the mesh-shaped metal collector electrode, and the metal collector electrode and the polarizable electrode are surely and firmly secured. It can be tightly integrated.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory view schematically showing, for explanation, the state of pressure molding according to the method of the present invention, and FIG. 2 is a front view schematically showing an example of a mesh-shaped metal collecting electrode used in the method of the present invention. It is.
[0013]
First, a mesh-shaped metal collector electrode (hereinafter referred to as a mesh collector electrode) is prepared. In this example, as shown in FIG. 2, the mesh-shaped collector electrode 11 for the positive electrode is rectangular by punching out an aluminum foil having a thickness of 50 μm, for example, which has been subjected to an expanding process, with a bladed press. And a lead portion 11a having a narrow width and a band shape are integrally formed. In this example, the mesh-shaped collector electrode 11 has a collector electrode body: 50 mm wide and 100 mm long, and a lead portion 11a: 15 mm wide and 100 mm long. A negative electrode mesh collector 14 described later is also produced in the same manner as the collector electrode 11.
[0014]
Next, a kneaded material for forming a polarizable electrode is prepared. That is, 80% by weight of activated carbon powder, 10% by weight of fluororesin PTFE as a binder, and 10% by weight of carbon black for improving electrical conductivity, water or alcohol as a kneading aid (for example, in the case of alcohol, activated carbon powder Kneader), kneader and the like are kneaded to a rubbery state. Then, the kneaded product is accommodated in a dryer set at a temperature of about 100 ° C. and the kneading aid is removed. After that, the lump is easy to mold and has a particle size of 0.5 mm or less. The mixture is then pulverized to obtain a kneaded product for forming a polarizable electrode.
[0015]
Next, as shown in FIG. 1, the polarizable electrode-forming kneaded material is put in a mold 4 having a predetermined dimension and having a rectangular shape in plan view, and is half the weight of the polarizable electrode when finished. Then, the first kneaded material layer 1 is made to have a substantially uniform thickness. Next, the mesh-shaped collector electrode 11 is placed on the kneaded material layer 1 in a state in which the lead portion 11a is drawn out of the concave portion of the mold 4, and the first kneaded material is further formed thereon. In the same manner as for layer 1, the kneaded material for forming a polarizable electrode is charged in half the weight of the polarizable electrode at the time of finishing, and the thickness is made substantially uniform to form the second kneaded material layer 2.
[0016]
After that, by performing pressure molding with the press machine 3, as shown in FIG. 3, the mesh-shaped collector electrode 11 is embedded in the polarizable electrode 12 with the lead portion 11a being drawn to the outside. In the example, an integrated electrode 10 for a positive electrode formed by integrating a polarizable electrode 12 having a thickness of 1.0 mm and a mesh-like collector electrode 11 is manufactured. The pressurizing condition by the press machine 3 is, for example, pressurizing force: 500 kgf / cm ² and pressurizing time: 1 min.
[0017]
In this way, the molding of the polarizable electrode 12 itself and the fixing and integration of the polarizable electrode 12 and the mesh-shaped collector electrode 11 can be performed simultaneously by performing pressure molding only once. The kneaded material for forming the polarizable electrode bites into a large number of small holes formed in the electrode 11, so that the mesh-like collector electrode 11 and the polarizable electrode 12 can be firmly and firmly integrated. In the same manufacturing procedure, as shown in FIG. 3, the mesh-like collector electrode 14 is embedded in the polarizable electrode 15 with the lead portion 14a being pulled out, and the mesh-like collector electrode 14 and the polarizable electrode are then embedded. As a result, an integrated electrode 13 for the negative electrode formed by integrating 15 is obtained.
[0018]
FIG. 4 is a perspective view showing an example of the overall configuration of the multilayer electric double layer capacitor in which the integrated electrode shown in FIG. 3 is incorporated.
[0019]
As shown in FIG. 4, the positive electrode integrated electrode 10 and the negative electrode integrated electrode 13 are alternately laminated in this example with separators 16 made of polypropylene fiber nonwoven fabric having a thickness of about 25 μm interposed therebetween. To do. And this electrode laminated body is accommodated in the rectangular outer case 19 in a state where the fastening plates 17 are arranged on the outermost sides on both sides and the fastening belt 18 is wound on the plates 17 and fastened in the stacking direction. Next, the lead portion 11a of the meshed collecting electrode 11 of each of the integrated electrodes 10 for the positive electrode is connected to the positive electrode external terminal 21 which is impregnated with the organic electrolytic solution and fixed to the case upper lid 20, and similarly the negative electrode external The lead 22a of the mesh collector 14 of each integrated electrode 13 for the negative electrode is connected to the terminal 22, respectively. Thereafter, the case upper lid 20 is attached to the opening of the case 19 and sealed.
[0020]
As described above, according to the method for manufacturing an integrated electrode according to the present invention, only by performing pressure molding once with a press machine, the polarizable electrode itself is molded, and the polarizable electrode and the mesh-shaped metal collector electrode The integrated electrodes 10 and 13 can be obtained with a smaller number of manufacturing steps than in the past, thereby improving the productivity of the electric double layer capacitor. Moreover, the metal collector electrodes 11 and 14 made of a mesh-like material having a large number of small holes, such as aluminum expanded foil, are used as the metal collector electrodes. Thus, the kneaded material for forming the polarizable electrode bites into a large number of small holes formed in the mesh-shaped metal collector electrode, and the metal collector electrode and the polarizable electrode are integrated firmly and firmly. Electrodes 10 and 13 can be manufactured. As a result, by incorporating it into an electric double layer capacitor, it is possible to obtain an electric double layer capacitor that has a small internal resistance and is resistant to mechanical vibration and impact.
[0021]
【The invention's effect】
As described above, according to the method of manufacturing an integrated electrode for an electric double layer capacitor according to the present invention, an integrated electrode formed by integrating a metal collecting electrode and a polarizable electrode can be formed with a smaller number of processes than in the past. It can be manufactured, thereby improving the productivity of the electric double layer capacitor, and further, it is possible to manufacture an integrated electrode in which the metal collector electrode and the polarizable electrode are firmly and firmly integrated. By incorporating this integrated electrode into an electric double layer capacitor, the internal resistance is small and suitable for large capacity to carry a large current. Also, it is resistant to mechanical vibration and shock and suitable for mounting on electric bicycles and electric vehicles. An electric double layer capacitor can be obtained.
[Brief description of the drawings]
FIG. 1 is an explanatory view schematically showing a state of pressure molding according to the method of the present invention for explanation.
FIG. 2 is a front view schematically showing an example of a mesh-shaped metal collector electrode used in the method of the present invention.
FIG. 3 is a perspective view schematically showing an integrated electrode according to the present invention.
4 is a perspective view showing an example of the overall configuration of a multilayer electric double layer capacitor in which the integrated electrode shown in FIG. 3 is incorporated, with a part thereof cut away.
FIG. 5 is a perspective view showing a positive electrode that is an integrated electrode manufactured by a conventional method.
6 is a perspective view showing the overall structure of the multilayer electric double layer capacitor in which the integrated electrode shown in FIG. 5 is incorporated, with a part thereof cut away. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... 1st kneaded material layer 2 ... 2nd kneaded material layer 3 ... Press 4 ... Metal mold | dies 10 ... Integrated electrode for positive electrodes 11 ... Mesh-shaped metal collector electrode for positive electrodes 11a ... Lead part 12 ... Minutes Polar electrode 13 ... Integral electrode for negative electrode 14 ... Mesh-shaped collector electrode 14a for negative electrode 14a ... Lead part 15 ... Polarizable electrode 16 ... Separator 19 ... Square outer case 20 ... Cover lid 21 ... Positive external terminal 22 ... Negative external terminal

Claims (3)

When manufacturing an integrated electrode that is used as a positive electrode and a negative electrode of a multilayer electric double layer capacitor and is formed by integrating a metal collector electrode and a polarizable electrode,
A kneaded material for forming a polarizable electrode is prepared by kneading at least a binder with activated carbon, and a predetermined amount of the kneaded material is charged into a mold having a concave portion having a rectangular shape in plan view . Then, a metal collector electrode is placed thereon so that there is a gap between the periphery and the mold side wall, and a predetermined amount of the kneaded material is put on the metal collector electrode. 2 and then press forming until the first kneaded material layer and the second kneaded material layer come into contact with each other in the gap and are integrated with each other by a pressurizer. With the lead part pulled out to the outside, a metal collector electrode other than the collector electrode lead part is embedded in the polarizable electrode up to its end so that the metal collector electrode and the polarizable electrode are integrated. manufactured integral electrode for an electric double layer capacitor, wherein (except those subsequently cut) that Method. A kneaded material for forming a polarizable electrode is prepared by kneading at least a binder with activated carbon, and a predetermined amount of the kneaded material is charged into a mold having a concave portion having a rectangular shape in plan view . Then, a metal collector electrode is placed thereon so that there is a gap between the periphery and the mold side wall, and a predetermined amount of the kneaded material is put on the metal collector electrode. 2 and then press forming until the first kneaded material layer and the second kneaded material layer come into contact with each other in the gap and are integrated with each other by a pressurizer. An integrated electrode in which the metal collector electrode is embedded in the polarizable electrode with the lead portion pulled out, and the metal collector electrode and polarizable electrode are integrated (except for those that are subsequently cut) And a plurality of the integrated electrodes are alternately stacked with a separator interposed therebetween, A step of obtaining an electrode laminate by arranging fastening plates on the outermost sides of both sides and winding a fastening belt on the fastening plates in the laminating direction;
A method for producing an electrode laminate for an electric double layer capacitor, comprising: The method according to claim 1 or 2, wherein the metal collector electrode is a mesh metal collector electrode.

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