JP4542947B2 - Manufacturing method of electric double layer capacitor - Google Patents

Description

  The present invention relates to a method for manufacturing an electric double layer capacitor.

  In recent years, electric double layer capacitors are required to be smaller, thinner and lighter.

  As an electric double layer capacitor that meets the demands for miniaturization, thickness reduction, and weight reduction, a multilayer electric double layer capacitor using an outer package such as a laminate film is known. Such a multilayer electric double layer capacitor can be easily reduced in thickness as compared with a wound electric double layer capacitor, and it is not necessary to use a metal can as an exterior body. There is an advantage that it can contribute to weight reduction.

  An electric double layer capacitor is charged and discharged by adsorption and desorption of ions without a chemical reaction, and therefore has a very long life with little deterioration of the electrolyte. In addition, physical adsorption / desorption due to the movement of ions proceeds faster than chemical reactions, and the internal resistance of electric double layer capacitors is lower than that of batteries. Can be discharged.

  Currently, electric double layer capacitors are used for backup power sources for portable devices, printers, remote controllers, memory cards and game machines, backup power sources for clock functions, instantaneous voltage drop compensators, etc., and for hybrid vehicles Expectation is also expected in applications such as auxiliary power and cogeneration.

  As a method of manufacturing a multilayer electric double layer capacitor, a laminate is formed by laminating a polarizable electrode and a separator, and this laminate is packaged in an exterior such as an aluminum laminate or a resin case in an impregnated state with an electrolytic solution. A method of accommodating the body and sealing the opening of the exterior body is used.

  In the electric double layer capacitor, the laminated body is formed by punching an electrode formed by forming an active material-containing layer containing an electrode active material on a current collector foil into a sheet-like piece, and laminating the electrode sheet. It is generally formed by this.

In addition, as a method of forming a laminate by laminating electrode sheets, for example, an exposed portion (lead portion) in which an active material-containing layer is not laminated is formed on one edge of a current collector foil in the electrode sheet, There is known a method of laminating a plurality of electrode sheets alternately so that the lead portions of the matching electrode sheets face each other in opposite directions and at least part of the lead portions do not overlap with other electrode sheets (for example, , See Patent Document 1). This facilitates the formation of the lead portion and reduces the resistance loss of the lead portion. In the laminated body having such a configuration, it is necessary to configure the anode and the cathode by electrically connecting the lead portions of the current collector foil formed in one direction of the laminated body and in the opposite direction. At this time, when the number of laminated layers is several tens and a thick laminated body is produced, it is difficult to directly weld tabs for electrical connection to external terminals like a thin laminated body. For this reason, a conductive spacer is arranged between the lead portions formed in the same direction, and finally, the laminated portion is formed by binding the lead portion and the laminated portion of the spacer by welding, rivets or the like.
Japanese Patent Laid-Open No. 11-274004

  When producing the electrochemical device described in Patent Document 1 having a laminate having the above-described configuration, the production does not take much time if the number of laminates is small, but the number of laminates is several tens or hundreds or more. In the case of producing a laminated body having a large thickness, it is necessary to laminate conductive spacers every time an electrode sheet is laminated. Therefore, it takes a very long time to produce the laminated body, resulting in poor production efficiency. is doing.

  In addition, the electrical contact is not always sufficient in the surface contact where the lead portion and the spacer are simply overlapped. Furthermore, when the external output terminal is welded to the end of the laminate after lamination, the spacer has a sufficient thickness so that it can be welded to the external output terminal, but the lead portion of the electrode sheet is very thick. Since it is thin (for example, about 20 μm), welding with an external output terminal tends to be insufficient. As a result, the electrical connection between the lead portion and the external output terminal becomes insufficient, causing an increase in internal resistance. In addition, a metal foil such as an aluminum foil is used as the current collector foil. However, the surface of the metal foil is easily oxidized to form a film, and the formation of this film makes the electrical connection between the lead portion and the spacer more difficult. This is sufficient to increase the internal resistance.

  The present invention has been made in view of the above-described problems of the prior art, and is a method for manufacturing an electric double layer capacitor including a laminate formed by laminating a plurality of electrode sheets, and the internal resistance is sufficiently reduced. Another object of the present invention is to provide a method for manufacturing an electric double layer capacitor capable of efficiently manufacturing the electric double layer capacitor.

  In order to achieve the above object, the present invention provides an edge of the current collector foil on both surfaces of a current collector foil made of a metal containing aluminum and a conductive spacer on an anvil having an uneven surface. And an electrode sheet on which an active material-containing layer is formed so as to form a lead portion, and the conductive spacer and the lead portion are stacked so that the conductive spacer and the lead portion overlap. Are bonded by applying ultrasonic waves while applying pressure with an ultrasonic horn having irregularities formed on the surface, and an electrode sheet with spacers and the electrode sheets with spacers and separators are alternately arranged. In addition, the stacked portions of the conductive spacer and the lead portion in the adjacent electrode sheets with the spacers face in opposite directions, and the stacked portions with the adjacent stacked portions are adjacent to each other. A plurality of electrode sheets with spacers arranged in a staggered manner so as not to overlap with the sheet, and a lamination step for obtaining a laminate, and a pressurizing step for pressurizing the lamination portion. A method for manufacturing a multilayer capacitor is provided.

  In such a manufacturing method, first, a conductive spacer (conductive shim) having one electron conductivity is formed on a lead portion (exposed portion where no active material-containing layer is formed) of one electrode sheet before lamination. By ultrasonic bonding, it is possible to obtain sufficient electrical connection between the lead portion of the electrode sheet and the conductive spacer. Further, by ultrasonically bonding the lead portion and the conductive spacer, the number of parts when the electrode sheets are stacked can be reduced, and the stacking time can be shortened. Furthermore, when an oxide film is formed on the surface of the current collector foil, the oxide film can be removed by ultrasonic bonding, and the electrical connection between the lead portion and the conductive spacer is made more satisfactory. Is possible.

  Here, the present inventors have found that the following problems arise when the electrode sheet and the conductive spacer are ultrasonically bonded. That is, the conductive spacer is fixed by biting into an anvil having irregularities (small quadrangular pyramidal projections on the surface) on the surface, and for transmitting ultrasonic waves to the electrode sheet, irregularities are formed on the surface like the anvil. The lead portion of the electrode sheet bites into and grips an ultrasonic horn having (a small number of small quadrangular pyramidal projections), and the ultrasonic horn vibrates at a high speed in a predetermined direction, thereby fixing the lead portion and the conductive spacer. Phase combined. At this time, the pyramid-shaped protrusions on the surface of the anvil and the horn bite into the surface on the ultrasonic horn side of the current collector foil constituting the lead portion and the surface on the anvil side of the conductive spacer, respectively. The part rises and a projection is formed. And when the laminated body is formed by laminating the electrode sheets in this state, the heights of the protrusions are accumulated, and the thicknesses of both edge portions (one lead portion side and the opposite lead portion side) of the laminated body are Thicker than the thickness of the central part (lamination part of the current collector foil and the active material containing layer), and the thickness of the entire laminated body becomes non-uniform, greatly affecting the quality and ease of assembly of the electric double layer capacitor. The present inventors have found that Furthermore, when an electric double layer capacitor is to be manufactured using a relatively large-sized exterior body capable of accommodating a laminate having both thickened edges, the electrolyte solution is impregnated with the laminate. The central portion of the electrode sheet where the active material-containing layer is formed expands (the active material-containing layer and the separator expand), resulting in insufficient internal contact and an increase in internal resistance. The present inventors have found that this is caused.

  On the other hand, in the manufacturing method of the present invention, a metal foil made of a metal containing aluminum is used as a current collecting foil, and a laminated portion of a lead portion of a laminate formed by laminating electrode sheets with spacers and a conductive spacer. Is applied to the lead portion of the current collector foil that is in contact with the conductive spacer, and is generated on the surface of the lead portion. The protrusions can be crushed, the thickness of the laminated portion of the laminate can be made the same as the thickness of the central portion, and a laminate having a uniform thickness can be obtained.

  And an electrical double layer capacitor in which internal resistance was fully reduced can be obtained by manufacturing a layered product through the above-mentioned ultrasonic bonding process, lamination process, and pressurization process. Further, since the conductive spacer and the electrode sheet are integrated, the electric double layer capacitor can be efficiently manufactured, and the manufacturing time can be shortened. In addition, by reducing the thickness of both edges of the multilayer body and making the thickness of the entire multilayer body uniform, it is possible to use a relatively small-sized exterior body and realize a reduction in the size of the electric double layer capacitor. On the other hand, expansion of the active material-containing layer and the separator when the laminate is impregnated with the electrolyte solution can be sufficiently suppressed, and an increase in internal resistance can be sufficiently prevented.

  In the ultrasonic bonding step, the positions of the conductive spacer and the lead portion are positioned using a positioning pin, and when the conductive spacer and the lead portion are pressed by the ultrasonic horn, It is preferable to retract the positioning pin so that the sonic horn does not contact the positioning pin.

  By positioning using the positioning pins, it is possible to suppress a positional shift between the lead portion and the conductive spacer in the electrode sheet, and to form a uniform electrode sheet with a spacer. In collecting the electrodes, it is advantageous in terms of product characteristics of the electric double layer capacitor to maximize the junction area between the lead portion and the conductive spacer and minimize the contact resistance. At this time, when the positioning pin is used, since ultrasonic bonding is usually performed by applying an ultrasonic horn so as to avoid the positioning pin, the entire surface in contact with the lead portion of the conductive spacer is the lead portion. And ultrasonic bonding is difficult. On the other hand, as described above, the positioning pin is retracted so as not to contact the ultrasonic horn, so that the position of the lead portion and the conductive spacer is fixed by the positioning pin until just before joining, while the ultrasonic wave is fixed. The positioning pin can be retracted during pressurization and ultrasonic bonding with a horn, which makes it possible to ultrasonically bond the entire surface of the conductive spacer in contact with the lead to the lead, thereby maximizing the bonding area. It is possible to secure it to the limit. As a result, it is possible to obtain an electric double layer capacitor having a sufficiently reduced internal resistance. Further, by retracting the positioning pin before contacting the ultrasonic horn, it is possible to prevent damage to the tip end portion of the positioning pin, and it is possible to perform the ultrasonic bonding process stably over a long period of time.

  Furthermore, in the said pressurization process, it is preferable to pressurize the said laminated part with the pressure of 0.78-1.09 MPa.

  By pressurizing the laminated portion of the lead portion and the conductive spacer under such a pressure condition, the protrusion formed on the conductive spacer can be more surely bite into the current collector foil, and the thickness uniformity of the laminate can be improved. It can be more sufficient. As a result, it is possible to efficiently manufacture an electric double layer capacitor in which the internal resistance is sufficiently suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the electrical double layer capacitor which can manufacture efficiently the electrical double layer capacitor in which internal resistance was fully reduced can be provided.

  Hereinafter, a preferred embodiment of a method for producing an electric double layer capacitor of the present invention will be described in detail with reference to the drawings. In the following description, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 is a side view schematically showing a main part of an ultrasonic bonding apparatus for performing an ultrasonic bonding process in the method for manufacturing an electric double layer capacitor of the present invention. In the ultrasonic bonding apparatus 10 shown in FIG. 1, one edge of the current collector foil 14 is exposed on both surfaces of a conductive spacer 12 having electronic conductivity and a current collector foil 14 made of a metal containing aluminum. The anvil 22 on which the conductive spacer 12 and the lead portion 18 are sequentially placed so that the electrode sheet 20 on which the active material-containing layer 16 is formed so as to constitute the lead portion 18 overlaps, and the lead portion 18. An ultrasonic horn 24 is provided that applies an ultrasonic wave while applying pressure to the laminated portion of the lead portion 18 and the conductive spacer 12 from the side.

  Here, the anvil 22 is made of, for example, die steel or high-speed steel, and the surface (mounting surface) in contact with the conductive spacer 12 of the anvil 22 has irregularities (for example, a small number of small pyramid-shaped projections). ) Is formed. Further, on the surface (pressure surface) in contact with the lead portion 18 of the ultrasonic horn 24, irregularities having different sizes and intervals from the irregularities formed on the anvil 22 (for example, numerous quadrangular pyramid-shaped numerous protrusions) are formed. Has been. When ultrasonically bonding the conductive spacer 12 and the lead portion 18, the irregularities formed on the surfaces of the anvil 22 and the ultrasonic horn 24 bite into the lead portion 18 and the conductive spacer 12, respectively. It is designed to grip these. Thereby, even if the ultrasonic horn 24 vibrates at a high speed in a predetermined direction (usually the left-right direction in FIG. 1) at the time of ultrasonic bonding, the lead portion 18 and the conductive spacer 12 are solid-phase bonded without being displaced. It will be.

  The current collector foil 14 is made of a metal containing aluminum (for example, aluminum or aluminum alloy), and is preferably an aluminum foil. The thickness of the current collector foil 14 is not particularly limited, but is preferably 15 to 40 μm, for example.

  The active material containing layer 16 is formed on both surfaces of the current collector foil 14. The active material-containing layer 16 is configured to include an electrode active material, a binder, a conductive aid having electronic conductivity, and the like. Examples of the electrode active material include granular or fibrous activated carbon that has been activated. In addition, the binder is not particularly limited as long as it can bind an electrode active material or a conductive additive. For example, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene (PE) , Polypropylene (PP), fluorine rubber and the like. Moreover, as a conductive support agent, if it is a particle | grains which have electronic conductivity, it will not restrict | limit, For example, carbon materials, such as carbon black and graphite, are mentioned.

  The electrode sheet 20 including the current collector foil 14 and the active material-containing layer 16 is produced as follows, for example. FIGS. 2A to 2C are explanatory views for explaining a process of forming the electrode sheet 20 from the original electrode sheet.

  First, as shown in FIG. 2A, a long electrode sheet original fabric 200 in which the active material-containing layer 16 is formed on both surfaces of the current collector foil 14 is produced. At this time, the active material-containing layer 16 is formed so that the lead portions 18 where the surface of the current collector foil 14 is exposed are formed at both edges in the short side direction (direction orthogonal to the longitudinal direction) of the electrode sheet original fabric 200. Form.

  Next, the obtained electrode sheet original fabric 200 is rolled through a calender roll to improve the density of the active material-containing layer 16 and improve the adhesion between the active material-containing layer 16 and the current collector foil 14.

  Next, as shown in FIG. 2B, the electrode sheet original fabric 200 is punched out in accordance with the scale of the electric double layer capacitor to be produced, and the electrode sheet 20 shown in FIG. 2C is obtained. At this time, the electrode sheet 20 in which the lead portions 18 are integrated can be obtained by punching out the original electrode sheet 200 so as to include the portion of the lead portions 18 described above.

  FIG. 3 is a perspective view schematically showing an example of the electrode sheet 20. With respect to the electrode sheet 20 obtained as described above, a positioning hole 36 is opened at a predetermined position of the lead portion 18, and a shape corresponding to the shape of the electric double layer capacitor for producing the end shape of the lead portion 18 is formed. The electrode sheet 20 shown in FIG. 3 can be obtained by processing. In addition, the electrode sheet 20 shown in FIG. 3 is provided with a long hole 38 for promoting electrolyte solution penetration and reducing the weight.

  The conductive spacer 12 is preferably made of a metal containing aluminum (for example, aluminum, aluminum alloy, etc.), and more preferably made of aluminum. Here, FIG. 4 is a perspective view schematically showing an example of the conductive spacer 12. As shown in FIG. 4, the conductive spacer 12 has a positioning hole 36 and a long hole 38, and has a shape that matches the lead portion 18 of the electrode sheet 20 shown in FIG.

  The thickness of the conductive spacer 12 is such that the electrode sheets 20 and the separators are alternately arranged, and the conductive spacers 12 and the lead portions 18 in the adjacent electrode sheets 20 are stacked so that the stacked portions face in opposite directions. In such a case, it is preferable that the conductive spacer 12 has a thickness that just fills the space between adjacent lead portions 18 facing in the same direction. That is, it is preferable that the thickness of the conductive spacer 12 be equal to the total thickness of one current collector foil 14, four active material-containing layers 16, and two separators.

  In the ultrasonic bonding process, as shown in FIG. 1, first, the conductive spacer 12 is aligned by passing the two positioning pins 26 through the two positioning holes 36 of the conductive spacer 12. 22 is arranged. Subsequently, the electrode sheet 20 is placed on the conductive spacer 12 while being aligned by passing the two positioning pins 26 through the two positioning holes 36 of the electrode sheet 20. Thereafter, an ultrasonic wave is applied to the laminated portion of the conductive spacer 12 and the lead portion 18 of the electrode sheet 20 from the lead portion 18 side while being pressed by the ultrasonic horn 24, so that the conductive spacer 12 and the lead portion 18 Join.

  Here, a lever 30 to which a cam follower 28 is attached is connected to the ultrasonic horn 24, and the cam follower 28 is also lowered as the ultrasonic horn 24 is lowered, and a pin lowering interlocking shaft 32 connected to the positioning pin 26. Press down. By doing so, the positioning pin 26 can be lowered in conjunction with the lowering of the ultrasonic horn 24, and the positioning pin 26 can be retracted immediately before the ultrasonic horn 24 contacts the positioning pin 26. Further, the pin lowering interlocking shaft 32 is pushed up by the spring 34 when the ultrasonic horn 24 is raised, and returns to its original position.

  In the ultrasonic bonding process, it is preferable that the ultrasonic wave applied to the ultrasonic horn 24 has a frequency of 20 to 40 kHz and a vibration width of 5 to 14 μm.

  By performing the above ultrasonic bonding process, the conductive spacer 12 and the lead portion 18 of the electrode sheet 20 are ultrasonically bonded, and the electrode sheet 20 and the conductive spacer 12 are integrated as shown in FIG. The electrode sheet 100 with a spacer can be obtained. In addition, protrusions are formed on the surface of the conductive spacer 12 that is in contact with the anvil 22 and the surface of the lead portion that is in contact with the ultrasonic horn 24 due to the unevenness of the surface of the anvil 22 or ultrasonic horn 24. The Rukoto.

  Next, in the method for producing an electric double layer capacitor of the present invention, a laminate is produced by alternately laminating electrode sheets with spacers 100 obtained through the ultrasonic bonding step and separators. To do.

  Here, FIG. 6 is a partial cross-sectional view schematically showing a stacked structure of a stacked body manufactured by a stacking process. As shown in FIG. 6, in the laminating step, the electrode sheets with spacers 100 and the separators 40 are alternately arranged, and the spacers 12 in the adjacent electrode sheets with spacers 100 and the lead portions 18 in the current collector 14 are laminated. A plurality of spacer-attached electrode sheets 100 are laminated such that the portions face each other in opposite directions and the stacked portions do not overlap with adjacent spacer-attached electrode sheets 100 to produce a laminate 300.

  The separator 40 constituting the laminated body 300 is made of an insulating porous body. For example, one or more of polyolefins such as polyethylene and polypropylene (in the case of two or more, lamination of two or more layers of films) Etc.), polyesters such as polyethylene terephthalate, thermoplastic fluororesins such as ethylene-tetrafluoroethylene copolymer, celluloses and the like. The form of the sheet includes a microporous membrane film, a woven fabric, a non-woven fabric, etc. having an air permeability measured by the method specified in JIS-P8117 of about 5 to 2000 sec / 100 cc and a thickness of about 5 to 100 μm.

  Next, in the method for manufacturing an electric double layer capacitor according to the present invention, a pressurizing step of pressurizing the stacked portion of the conductive spacer 12 and the lead portion 18 in the stacked body 300 obtained through the above-described stacking step is performed.

  In the pressurizing step, the pressure for pressurizing the laminated portion is preferably 0.78 to 1.09 MPa, and more preferably 0.87 to 1.0 MPa.

  By performing such a pressurizing step, the protrusion generated on the surface of the conductive spacer 12 in the ultrasonic bonding step can be caused to bite into the lead portion 18 of the current collector foil 14, and the protrusion generated on the surface of the lead portion 18 can be formed. Can be crushed. As a result, the thickness of the laminated portion of the laminated body 300 can be made the same as the thickness of the central portion, and the laminated body 300 having a uniform thickness can be obtained.

  After the pressurizing step, as shown in FIG. 7, the anode external output terminal 50 is welded to one laminated portion of the laminated body 300 as necessary, and the cathode external output terminal 60 is attached to the opposite laminated portion. The electric double layer capacitor is completed by being welded and housed in the outer package in an impregnated state with the electrolyte solution.

  Here, the electrolyte solution is not particularly limited, and both an aqueous electrolyte solution and a nonaqueous electrolyte solution (nonaqueous electrolyte solution using an organic solvent) used in known electric double layer capacitors and the like may be used. it can. Alternatively, a solid electrolyte monomer may be impregnated into a separator and cured to form a polymer.

  Moreover, it does not restrict | limit especially as an exterior body, The exterior body used for the well-known electrical double layer capacitor etc. can be used.

  As mentioned above, although one Embodiment of the manufacturing method of the electrical double layer capacitor of this invention was described in detail, this invention is not limited to the said embodiment.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

Example 1
First, activated carbon, a binder, and a solvent were kneaded to prepare an active material-containing layer forming coating solution. This coating solution is applied to both sides of a long aluminum foil (thickness: 20 μm) as a current collector foil, and the solvent is removed by drying, whereby the active material-containing layer is formed on both sides of the aluminum foil. The electrode sheet raw material was obtained. The coating solution is applied so that both ends in the short direction of the long aluminum foil are exposed, and the electrode sheet original fabric has lead portions in which no active material-containing layer is formed at both ends in the short direction. To be formed.

Next, the obtained electrode sheet is rolled through a calender roll, punched into 35 mm × 45 mm so as to have a 4.5 mm × 45 mm lead portion at one end in the longitudinal direction, and two positioning holes of φ2 mm are formed in the lead portion. An electrode sheet having the same structure as that shown in FIG. 3 was opened. Next, a conductive spacer (thickness: 460 μm) having two positioning holes of φ2 mm and having a structure similar to that shown in FIG. 4 is prepared, and this is applied to the ultrasonic bonding apparatus shown in FIG. The positioning pins of the apparatus were arranged so as to pass through the positioning holes of the conductive spacer, and the electrode sheet was further arranged so that the positioning pins of the apparatus passed through the positioning holes of the electrode sheet. Thereafter, the ultrasonic horn is lowered and brought into contact with the lead portion of the electrode sheet, and the lead portion and the conductive spacer are pressurized with a pressure of 4.9 MPa (50 kgf / cm ² ), while the frequency of 40 kHz is applied to the ultrasonic horn. A conductive spacer was bonded to the lead portion of the electrode sheet by applying 7 μm ultrasonic waves for 0.2 seconds (ultrasonic bonding step). The positioning pin was retracted in conjunction with the lowering of the ultrasonic horn immediately before the ultrasonic horn contacted. At this time, the lead portion surface contacted with the horn is formed on the surface of the ultrasonic horn as shown in FIG. 8 (optical micrograph, 100 times) and FIG. 9 (scanning electron micrograph, 600 times). Concavities and convexities (quadrangular pyramidal protrusions) that bite into the recesses and protrusions were formed. Further, as shown in FIG. 10 (photomicrograph, 100 times) and FIG. 11 (scanning electron micrograph, 1000 times), the surface of the conductive spacer contacted with the anvil is uneven. (4-Pyramidal projections) bite into the recesses and protrusions.

  The electrode sheets with spacers thus obtained were set in a laminating apparatus, and as shown in FIG. 6, electrode sheets and separators (41.5 mm × 46 mm, thickness 30 μm) were alternately and adjacent to each other. 186 electrode sheets were alternately laminated so that the lead portions with spacers faced in opposite directions and the lead portions with spacers did not overlap with adjacent electrode sheets (lamination process). ).

  Next, the laminated part of the conductive spacer and the current collector foil at both ends of the laminated body was pressurized with a pressure of 0.98 MPa to make the entire laminated body uniform thickness (pressurizing step). Thereafter, one side surface of the laminated body where the laminated portion is formed and the anode external output terminal are welded, and the opposite side surface opposite to the one side surface of the laminated body and the cathode external output terminal are welded. Thus, an electric double layer capacitor was produced. When the internal resistance of the obtained electric double layer capacitor was measured, the results shown in Table 1 were obtained.

(Comparative Example 1)
First, activated carbon, a binder, and a solvent were kneaded to prepare an active material-containing layer forming coating solution. This coating solution is applied to both sides of a long aluminum foil (thickness: 20 μm) as a current collector foil, and the solvent is removed by drying, whereby the active material-containing layer is formed on both sides of the aluminum foil. The electrode sheet raw material was obtained. The coating solution is applied so that both ends in the short direction of the long aluminum foil are exposed, and the electrode sheet original fabric has lead portions in which no active material-containing layer is formed at both ends in the short direction. To be formed.

  Next, the obtained electrode sheet is rolled through a calender roll, punched into 35 mm × 45 mm so as to have a 4.5 mm × 45 mm lead portion at one end in the longitudinal direction, and two positioning holes of φ2 mm are formed in the lead portion. An electrode sheet having the same structure as that shown in FIG. 3 was opened.

  The electrode sheet thus obtained was set in a laminating apparatus, and as shown in FIG. 6, electrode sheets and separators (41.5 mm × 46 mm, thickness 30 μm) were alternately arranged, and lead portions in adjacent electrode sheets 4 have two positioning holes of φ2 mm between the lead portions arranged in the same direction so that the lead portions are opposite to each other and the lead portions do not overlap with the adjacent electrode sheet. While arranging conductive spacers (thickness: 460 μm) having the same structure as that shown, 186 electrode sheets were alternately stacked to obtain a laminate.

  Next, the side surface on which the laminated portion of the conductive spacer of the laminate and the current collector foil are formed and the anode external output terminal are welded, and the opposite side of the laminate opposite to the one side is An electric double layer capacitor was fabricated by welding the external output terminal for the cathode. When the internal resistance of the obtained electric double layer capacitor was measured, the results shown in Table 1 were obtained.

  As is clear from the results shown in Table 1, the electric double layer capacitor obtained by the method for producing an electric double layer capacitor of the present invention (Example 1) was obtained by the method for producing an electric double layer capacitor of Comparative Example 1. It was confirmed that the internal resistance was sufficiently reduced as compared with the obtained electric double layer capacitor.

It is a side view which shows typically the principal part of the ultrasonic bonding apparatus for performing the ultrasonic bonding process in the manufacturing method of the electrical double layer capacitor of this invention. (A)-(c) is explanatory drawing for demonstrating the process of forming an electrode sheet from an electrode sheet original fabric. 2 is a perspective view schematically showing an example of an electrode sheet 20. FIG. 2 is a perspective view schematically showing an example of a conductive spacer 12. FIG. It is a perspective view which shows typically an example of the electrode sheet with a spacer. It is a fragmentary sectional view which shows typically the laminated structure of the laminated body produced by a lamination process. 4 is a perspective view schematically showing a state in which an external output terminal is welded to a laminated body 300. FIG. It is an optical microscope photograph (100 times) of the lead part surface after an ultrasonic joining process. It is a scanning electron micrograph (600 times) of the lead part surface after an ultrasonic joining process. It is an optical microscope photograph (100 times) of the conductive spacer surface after an ultrasonic bonding process. It is a scanning electron micrograph (1000 times) of the conductive spacer surface after an ultrasonic bonding process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Ultrasonic bonding apparatus, 12 ... Conductive spacer, 14 ... Current collecting foil, 16 ... Active material containing layer, 18 ... Lead part, 20 ... Electrode sheet, 22 ... Anvil, 24 ... Ultrasonic horn, 26 ... Positioning pin 28 ... Cam follower, 30 ... Lever, 32 ... Pin lowering interlocking shaft, 34 ... Spring, 36 ... Positioning hole, 40 ... Separator, 50 ... External output terminal for anode, 60 ... External output terminal for cathode, 100 ... Electrode with spacer Sheet, 200 ... electrode sheet original fabric, 300 ... laminate.

Claims (3)

An active part is formed on the anvil having a concavo-convex surface so that one edge of the current collector foil is exposed on both surfaces of the conductive spacer and the current collector foil made of a metal including aluminum. An ultrasonic horn in which an electrode sheet formed with a substance-containing layer is laminated so that the conductive spacer and the lead portion overlap, and the conductive spacer and the lead portion are formed with irregularities on the surface. An ultrasonic bonding step of applying an ultrasonic wave while applying pressure and bonding to obtain an electrode sheet with a spacer;
The electrode sheets with spacers and the separators are alternately arranged, and the stacked portions of the conductive spacers and the lead portions in the adjacent electrode sheets with the spacers face in opposite directions, and the stacked portions are Laminating step of stacking a plurality of the electrode sheets with spacers so as not to overlap with the adjacent electrode sheets with spacers to obtain a laminate,
A pressurizing step of pressurizing the laminated portion;
The manufacturing method of the electrical double layer capacitor characterized by including this.   In the ultrasonic bonding step, the position of the conductive spacer and the lead portion is positioned using a positioning pin, and the ultrasonic horn is used to pressurize the conductive spacer and the lead portion with the ultrasonic horn. The method of manufacturing an electric double layer capacitor according to claim 1, wherein the positioning pin is retracted so as not to contact the positioning pin. 3. The method of manufacturing an electric double layer capacitor according to claim 1, wherein, in the pressurizing step, the laminated portion is pressurized with a pressure of 0.78 to 1.09 MPa.

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