JP2009182048A - Manufacturing method of electrochemical capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an electrochemical capacitor capable of efficiently executing heat sealing capable of maintaining high airtightness at an electrode terminal peripheral part, in the manufacturing method of the electrochemical capacitor composed by sealing a laminate comprising a positive electrode body, a negative electrode body and a separator in a flat container in the state of exposing the distal end of the terminal of the positive electrode body and the distal end of the terminal of the negative electrode body to the outside. <P>SOLUTION: (1) When performing heat sealing, it is performed while heating or cooling a welding agent on the terminal distal end side at a temperature lower than the heating temperature of the welding agent on the side opposite to the distal end. (2) The welding agent of a melting temperature higher than that of the welding agent on the side opposite to the distal end is arranged as the welding agent on the terminal distal end side beforehand and heat sealing is performed. (3) A thermosetting resin is arranged on the terminal distal end side of the welding agent beforehand and heat sealing is executed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for efficiently producing an electrochemical capacitor such as an electric double layer capacitor that accumulates electricity in an electric double layer that is an interface between a polarizable electrode such as activated carbon and an electrolytic solution.

  In recent years, electrochemical capacitors such as an electric double layer capacitor that accumulates electricity in an electric double layer that is an interface between a polarizable electrode such as activated carbon and an electrolytic solution have been put into practical use as a power storage medium. As a general structure of an electrochemical capacitor, an electrode sheet made of a current collector such as a metal foil and a polarizable electrode such as activated carbon and a separator are alternately laminated to form a laminate, and further impregnated with an electrolyte. The laminated body is sealed in a container to form an electrochemical capacitor.

  In addition, an electrochemical capacitor is manufactured by forming a laminate of an electrode sheet and a separator into a sandwich shape for a square electrochemical capacitor and a roll shape for a cylindrical electrochemical capacitor. And the lead portion of the negative electrode body) are connected to the respective terminals, the laminated body is accommodated in the container, the electrolytic solution is injected from the opening of the container, the laminated body is impregnated with the electrolytic solution, and the tip of the electrode terminal is external Many methods have been implemented to seal the container while exposed to water.

  In such an electrochemical capacitor, an organic electrolytic solution capable of obtaining a large energy density is generally used as the electrolytic solution. However, there is a disadvantage in that the withstand voltage decreases due to a small amount of moisture absorption and is likely to deteriorate. Therefore, the laminate is sufficiently dried before injecting the electrolytic solution, and the subsequent operation is performed in an inert gas atmosphere until the container is sealed. In addition, the container is usually sealed by preliminarily providing a welding agent on the electrode terminal portion and pressing and heat-sealing with two heated heat seal bars sandwiching the container. .

The seal on the electrode terminal exposed side of the container cannot be uniformly pressurized due to the thickness of the electrode terminal during heat sealing, and it is difficult to perform heat sealing well. There was a concern that the lifetime of the capacitor would be shortened. Further, there has been a concern that the resin film of the outer packaging material of the container is damaged by the corner portion of the electrode terminal, and the metal foil exposed from the cut contacts the electrode terminal and short-circuits. As an example of a solution to such a problem, Patent Document 1 discloses that when a container is heat-sealed, a raised portion that covers the end surface of the resin film of the container is formed by a heat-sealing welding agent. Has been. It is described that the container can be easily sealed by heat sealing with such a configuration.
JP 2002-280271 A

However, as described in Patent Document 1, a method of using an excess welding agent and extruding the excess welding agent from the edge of the seal portion of the container by heat sealing to form a raised portion to be covered However, it is difficult to carry out the post-processing work until the welding agent cools and hardens, and in some cases, the welding agent that melts and protrudes out of the container in a disorderly manner can be obtained. It is necessary to remove this, which causes inconvenience in carrying out the continuous process.
Therefore, the problem to be solved by the present invention is to provide an electrochemical capacitor manufacturing method capable of efficiently performing heat sealing that can maintain high airtightness in the periphery of electrode terminals.

  As a result of intensive studies to solve these problems, the inventors of the present invention seal the laminate in a flat container by placing a welding agent on the electrode terminal portion and heating it to perform heat sealing. In the method for manufacturing an electrochemical capacitor, (1) during heat sealing, the welding agent on the terminal tip side is heated or cooled at a low temperature, and (2) a welding agent having a high melting temperature is applied to the terminal tip side. (3) By placing a thermosetting resin on the terminal end side of the welding agent, it is possible to prevent excess welding agent from melting and sticking out to the outside of the container during heat sealing. It has been found that heat sealing that can be performed and can maintain high airtightness can be carried out efficiently, and has reached the present invention.

  That is, the present invention relates to a laminate composed of a positive electrode body, a negative electrode body, and a separator, and a welding agent previously disposed on a terminal portion in a state where the front end of the positive electrode body terminal and the front end of the negative electrode body terminal are exposed to the outside. In the method of manufacturing an electrochemical capacitor that is sealed in a flat container by heating and heat sealing, the heat sealing is performed by using the welding agent on the terminal tip side and the heating temperature of the welding agent on the opposite side to the tip. A method for producing an electrochemical capacitor, which is performed while heating or cooling at a lower temperature.

  Further, the present invention provides a laminate comprising a positive electrode body, a negative electrode body, and a separator, in which the tip of the terminal of the positive electrode body and the tip of the terminal of the negative electrode body are exposed to the outside and are previously disposed on the terminal portion. In the method of manufacturing an electrochemical capacitor that is sealed in a flat container by heating the agent and heat-sealing, the heat seal is used as a welding agent on the terminal tip side than the welding agent on the side opposite to the tip. An electrochemical capacitor manufacturing method is characterized in that a welding agent having a high melting temperature is disposed.

  Further, the present invention provides a laminate comprising a positive electrode body, a negative electrode body, and a separator, in which the tip of the terminal of the positive electrode body and the tip of the terminal of the negative electrode body are exposed to the outside and are previously disposed on the terminal portion. In the method of manufacturing an electrochemical capacitor that is sealed in a flat container by heating the agent and performing heat sealing, the heat sealing is performed by placing a thermosetting resin on the terminal end side of the welding agent. This is a method for manufacturing an electrochemical capacitor.

  In the method for producing an electrochemical capacitor of the present invention, even if an excessive amount of a welding agent for sealing the laminate to the container by heat sealing is used, the excess welding agent is prevented from melting and protruding to the outside of the container. Therefore, heat sealing that can maintain high airtightness can be carried out efficiently without waiting for subsequent work until the welding agent cools and hardens, and without removing the welding agent outside the container. Is possible. In addition, it becomes possible to perform heat sealing in a state where a part of the welding agent or thermosetting resin on the tip side of the terminal is exposed from the flat container, and the electrical insulation between the electrode terminal and the container can be improved. .

The method for producing an electrochemical capacitor of the present invention includes a laminated body composed of a positive electrode body, a negative electrode body, and a separator, with a terminal portion in advance in a state where the tip of the terminal of the positive electrode body and the tip of the terminal of the negative electrode body are exposed to the outside. It is applied to a method of manufacturing an electrochemical capacitor such as an electric double layer capacitor which is sealed in a flat container by heating the welding agent disposed in the container and performing heat sealing.
Hereinafter, although the manufacturing method of the electrochemical capacitor of this invention is demonstrated in detail based on FIGS. 1-6, this invention is not limited by these.

  In the method for manufacturing an electrochemical capacitor according to the present invention, as shown in FIG. 1, a welding agent plate 2 made of a molding of a welding agent is disposed and integrated with a terminal 3 of a positive electrode body and a terminal 4 of a negative electrode body. The electrode terminal member 1 or the electrode terminal member in which the welding agent plate 2 and the positive electrode terminal 3 are integrated, and the electrode terminal member in which the welding agent plate 2 and the negative electrode terminal 4 are integrated are used. Furthermore, the electrode terminal member provided with the pressure release valve (pressure release cylinder) in the center part of the electrode terminal member 1 as shown in FIG. 1 can also be used. Hereinafter, an electrode terminal member 1 as shown in FIG. 1 will be described as an example, but in the present invention, an electrode terminal member in which a terminal of a welding agent plate and a positive electrode body is integrated, a welding agent plate and a negative electrode body. An electrode terminal member integrated with a terminal and an electrode terminal member provided with a pressure release valve (pressure release cylinder) can also be used in the same manner as the electrode terminal member shown in FIG.

  In the present invention, as shown in FIG. 2, the laminate composed of the positive electrode body, the negative electrode body, and the separator includes a lead portion 8 of the positive electrode body and a lead portion 9 of the negative electrode body, each of which is a terminal of the electrode terminal member 1. 3 and the laminated body 7 of the structure which can be connected to the terminal 4 is used. The laminate 7 is bonded to the electrode terminals 3 and 4 of the electrode terminal member 1 at the lead portions 8 and 9 by welding or the like, and as shown in FIG. 3, a flat made of metal foil covered with a plastic film having an opening 11. The container 10 is stored. During this time, the laminated body and the container are dried.

  Next, an operation of injecting the electrolytic solution into the container and impregnating the electrochemical capacitor cell with the electrolytic solution, and removing the gas adsorbed on the polarizable electrode by reducing the pressure in the container is performed. By doing in this way, a laminated body can be efficiently impregnated with electrolyte solution. In addition, if necessary, in order to electrolyze and remove moisture and functional groups contained in the polarizable electrode between the injection of the electrolyte and the sealing of the container, the electrode terminal is energized and subjected to electrolytic purification. . Then, the container is sealed by heating and heat-sealing the welding agent disposed on the terminal portion of the electrode terminal member, and an electrochemical capacitor is manufactured. In the present invention, the heat sealing method is described below. It has the following features.

That is, in the manufacturing method of the electrochemical capacitor according to the first aspect of the present invention, the heat of the welding agent 5 on the terminal tip side of the electrode terminal member 1 is set to be higher than the heating temperature of the welding agent 6 on the side opposite to the tip. It is characterized by being performed while heating or cooling at a low temperature.
For example, as shown in FIGS. 3 and 4, the heat seal in the manufacturing method of the first embodiment is held in a state where the welding agent plate made of the welding agent (5, 6) and the inside of the opening 11 of the container are in contact with each other. Thereafter, the heating is performed by pressing the two opening portions of the container with two heated heat seal bars. At this time, the temperature of the welding agent 5 on the tip side of the terminal is welded on the side opposite to the tip. The temperature of the agent 6 is controlled to be 5 ° C. or more, preferably 10 ° C. or more. Such heat sealing is performed by a method of weakening, stopping, or cooling the portion of the heat sealing bar corresponding to the welding agent on the terminal tip side.

Moreover, the manufacturing method of the electrochemical capacitor of the 2nd form of this invention uses a heat seal as the welding agent 5 of the terminal front end side of the electrode terminal member 1, and the melting temperature is higher than the welding agent 6 on the opposite side to the front end. It is characterized by arranging a high welding agent.
The electrode terminal member welding agent in the manufacturing method of the second embodiment is preferably 10 ° C. or more so that the difference in melting temperature between the terminal tip side welding agent and the opposite side welding agent is 5 ° C. or more. Is selected as follows. In any of the production methods of the present invention, a thermoplastic resin that normally melts at about 50 to 200 ° C. is used as the welding agent, and among them, polyolefin resins such as polyethylene and polypropylene are preferable. For example, as shown in FIGS. 3 and 4, the heat seal in the manufacturing method of the second embodiment forms the side surface of the welding agent plate made of the welding agent 5 and the welding agent 6 and the inside of the opening 11 of the container. After being kept in contact, it is performed by pressing with two heat seal bars heated almost uniformly with the opening of the container sandwiched therebetween.

Moreover, the manufacturing method of the electrochemical capacitor of the 3rd form of this invention is the electrode as shown in FIG. 5 which has arrange | positioned the molded object of the thermosetting resin 12 to the terminal front end side of the welding agent board 2 previously in heat sealing. This is performed using the terminal member 1.
For example, as shown in FIG. 6, the heat seal in the manufacturing method of the third embodiment holds the side surfaces of the welding agent plate 2 and the thermosetting resin molding 12 in contact with the inside of the opening 11 of the container. After that, it is performed by pressing with two heat seal bars heated almost uniformly with the opening of the container sandwiched therebetween. At that time, as shown in FIG. 6, a part of the thermosetting resin molded body 12 on the terminal tip side is exposed from the flat container, and heat sealing is performed, thereby electrically insulating the electrode terminal and the container. Can be improved.
In the present invention, in any form of the manufacturing method, the process from injection of the electrolytic solution to sealing of the container is performed in an inert gas atmosphere.

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited by these.

[Example 1]
(Production of electrode terminal members)
In order to mold the electrode terminal member by flowing the molten synthetic resin, an assembly-type stainless steel mold as shown in FIG. 7 was manufactured. A mold release agent is applied to the inside of the mold, and a positive electrode body terminal 3 and a negative electrode body terminal 4 (each of which has a length of 60 mm, a width of 30 mm, and a thickness of 0.5 mm) are formed in a slit-like gap on the side surface. After passing through the mold 13 as shown in FIG. 7, a low density polyethylene resin (melting point: 106 to 108 ° C.) melted at 130 ° C. was poured into the mold. After the resin was cooled to a solid state, the mold was disassembled and the molded body was taken out. The burr on the surface of the synthetic resin was removed and the corners of the ends were shaved to obtain an electrode terminal member 1 having a welding agent plate 2 having a length of 150 mm, a width of 15 mm, and a thickness of 3 mm as shown in FIG.

(Production of electric double layer capacitor)
An electrode sheet obtained by applying and drying a coating liquid containing activated carbon, carbon black, etc. on an aluminum foil, and a paper separator (thickness 50 μm), the lead portion of the electrode terminal member positive electrode alternately A total of 30 layers were laminated so that they could be connected to the negative electrode terminal, and a square laminate (thickness 10 mm) having a side of 100 mm excluding the lead portion was manufactured. Next, after the lead part of the positive electrode body and the lead part of the negative electrode body were bonded to the electrode terminals of the electrode terminal member by welding, they were dried under reduced pressure at 160 ° C. for 24 hours using a vacuum dryer.
In addition, a square flat container having a side of 150 mm and having an aluminum foil whose surface was covered with a plastic film as a base material was dried under reduced pressure at 105 ° C. for 15 hours using a vacuum dryer. This flat container has an opening on one side.

  After the laminate, the electrode terminal member, and the flat container are cooled to room temperature under a nitrogen atmosphere, as shown in FIG. 3, the electrode terminal member is laminated so that the welding agent plate is in contact with the inside of the opening of the container. The body was inserted into the container. The upper part of the welding agent plate was exposed from the container with a width of 2 mm in order to improve the electrical insulation between the electrode terminal and the container. Next, 90 ml of an electrolytic solution in which an ammonium salt or the like was dissolved in a propylene carbonate solvent was injected from the opening of a flat container. After completing the injection of the electrolytic solution, the laminate was decompressed by a vacuum pump for 30 minutes, and the laminate was decompressed. During this period, the electrode terminal was energized to perform electrolytic purification.

Then, using two heat seal bars that can be controlled separately at the top and bottom, while pressing with the opening of the container sandwiched, only the welding agent on the side opposite to the tip is 132 ° C. at the temperature of the heat seal bar. And heat sealed, and the flat container was sealed to obtain an electric double layer capacitor.
It was confirmed that the flat container was sealed while the excess welding agent melted and did not protrude outside the container, and the airtightness was maintained.

[Example 2]
(Production of electrode terminal members)
In the manufacture of the electrode terminal member of Example 1, the inside of the mold shown in FIG. 7 was divided into two parts, and a high-density polyethylene resin (melting point: 132 to 134 ° C.) melted at 150 ° C. was flown to the terminal tip side (width 5 mm). After that, the electrode terminal was removed in the same manner as in Example 1 except that the two-partitioned partition was removed and a low-density polyethylene resin (melting point: 106 to 108 ° C.) melted at 130 ° C. was poured on the opposite side (25 mm in width) of the terminal. A member was produced.

(Production of electric double layer capacitor)
Next, from the production of the laminate to the injection of the electrolytic solution, the reduced pressure treatment of the laminate, and the electrolytic purification were performed in the same manner as in Example 1.
Thereafter, the temperature of the heat seal bar is set so that the heating of the welding agent on the side opposite to the welding agent on the tip side becomes uniform while pressing with the two heat seal bars sandwiching the opening of the container. To 132 ° C. and heat sealed, and the flat container was sealed to obtain an electric double layer capacitor.
It was confirmed that the flat container was sealed while the excess welding agent melted and did not protrude outside the container, and the airtightness was maintained.

[Example 3]
(Production of electrode terminal members)
In the manufacture of the electrode terminal member of Example 1, the inside of the mold shown in FIG. 7 was divided into two parts, and after phenol resin (thermosetting) was placed on the terminal tip side (width 5 mm), the side opposite to the terminal tip ( An electrode terminal member was produced in the same manner as in Example 1 except that a low-density polyethylene resin (melting point: 106 to 108 ° C.) melted at 130 ° C. was poured into a width of 25 mm.

(Production of electric double layer capacitor)
Next, from the production of the laminate to the injection of the electrolytic solution, the reduced pressure treatment of the laminate, and the electrolytic purification were performed in the same manner as in Example 1.
Thereafter, the temperature of the heat seal bar is set so that the heating of the welding agent on the side opposite to the welding agent on the tip side becomes uniform while pressing with the two heat seal bars sandwiching the opening of the container. To 132 ° C. and heat sealed, and the flat container was sealed to obtain an electric double layer capacitor.
It was confirmed that the flat container was sealed while the excess welding agent melted and did not protrude outside the container, and the airtightness was maintained.

[Comparative Example 1]
In the production of the electric double layer capacitor of Example 1, both the welding agent on the terminal tip side and the welding agent on the opposite side to the tip were both heated to 132 ° C. at the temperature of the heat seal bar and heat sealed. Similarly, an electric double layer capacitor was manufactured.
It was confirmed that the flat container was sealed by the excessive welding agent melting and protruding out of the container.

  As described above, the electrochemical capacitor according to the embodiment of the present invention can prevent the excessive welding agent from melting and protruding to the outside of the container at the time of heat sealing, and a heat seal capable of maintaining high airtightness. It was confirmed that it could be implemented efficiently.

The perspective view which shows an example of the electrode terminal member in the electrochemical capacitor of this invention The perspective view which shows an example of the laminated body in this invention Front configuration diagram showing an example of an electrochemical capacitor of the present invention Side structure diagram showing an example of an electrochemical capacitor of the present invention The perspective view which shows an example of electrode terminal members other than FIG. 1 in the electrochemical capacitor of this invention. Front view showing an example of the electrochemical capacitor of the present invention other than FIG. The perspective view which shows an example of the metal mold | die for shape | molding an electrode terminal member in this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrode terminal member 2 Welding agent board 3 Terminal of the positive electrode body of an electrode terminal member 4 Terminal of the negative electrode body of an electrode terminal member 5 Welding agent of the terminal tip side 6 Welding agent on the opposite side to the tip 7 Laminated body 8 Positive electrode body of the laminated body 9 Lead portion of the negative electrode body of the laminated body 10 Flat container 11 Open portion of the flat container 12 Thermosetting resin 13 Mold

Claims (6)

  Heating the laminate composed of the positive electrode body, the negative electrode body, and the separator by heating the welding agent disposed in advance in the terminal portion with the tip of the terminal of the positive electrode body and the tip of the terminal of the negative electrode body exposed to the outside. In the method of manufacturing an electrochemical capacitor which is sealed in a flat container by performing sealing, the heat sealing is performed by using a welding agent on the terminal tip side at a temperature lower than the heating temperature of the welding agent on the side opposite to the tip. A method for producing an electrochemical capacitor, which is performed while heating or cooling.   Heating the laminate composed of the positive electrode body, the negative electrode body, and the separator by heating the welding agent disposed in advance in the terminal portion with the tip of the terminal of the positive electrode body and the tip of the terminal of the negative electrode body exposed to the outside. In the method of manufacturing an electrochemical capacitor that is sealed in a flat container by performing sealing, the heat seal is a welding agent having a higher melting temperature than the welding agent on the side opposite to the tip as the welding agent on the tip side of the terminal. A method for producing an electrochemical capacitor, comprising:   Heating the laminate composed of the positive electrode body, the negative electrode body, and the separator by heating the welding agent disposed in advance in the terminal portion with the tip of the terminal of the positive electrode body and the tip of the terminal of the negative electrode body exposed to the outside. In the method of manufacturing an electrochemical capacitor which is sealed in a flat container by performing sealing, the heat sealing is performed by placing a thermosetting resin on the terminal end side of the welding agent. A method for manufacturing a capacitor.   The method for producing an electrochemical capacitor according to claim 1, wherein heat sealing is performed while controlling the temperature of the welding agent on the terminal tip side to be 5 ° C or more lower than the temperature of the welding agent on the side opposite to the tip.   The method for producing an electrochemical capacitor according to claim 2, wherein the melting temperature of the welding agent on the terminal tip side is higher by 5 ° C. than the melting temperature of the welding agent on the side opposite to the tip.   4. The method for producing an electrochemical capacitor according to claim 3, wherein heat sealing is performed in a state in which a part of the thermosetting resin on the terminal tip side is exposed from the flat container.

Images