JP3797813B2 - Electric double layer capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a low equivalent series resistance at a high breakdown voltage by housing a plurality of capacitor elements carrying lead surfaces on their upper and lower surfaces in a metallic case, in such a way that the elements are connected in series by bringing the elements into face-contact with each other through conductive rubber sheets. SOLUTION: A capacitor element 2 is manufactured by winding a cathode-side electrode body and an anode-side electrode body together by respectively arranging the electrode bodies, so that the lead section of the former may be protruded downward from the lower edge section of a separator, and the protruded lead section of the latter is arranged so that the lead section may be protruded upward from the upper edge section of the separator. Then an electrolyte is formed between the electrode bodies facing each other on both sides of the separator. In addition, the protruded lead sections are tilted inward toward the center of the element 2 and an anode lead surface 7 and a cathode lead surface 8 are formed on the upper and lower surfaces of each lead section. Thereafter, a plurality of capacitor elements 2 thus manufactured is housed in a vertically long metallic case 10, in a state where the elements 2 are connected in series by bringing the elements into face-contact with each other through conductive rubber sheets 16.

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric double layer capacitor.
[0002]
[Prior art]
The electric double layer capacitor is made of, for example, a metal foil in which a lead electrode is fixed in advance on a polarizable electrode kneaded with activated carbon, carbon and polytetrafluoroethylene (PTFE) as a binder. After bonding a plate-like or mesh-like current collector with a conductive adhesive to form an electrode body, a pair of the electrode bodies are wound through a separator to form a capacitor element, and impregnated with an electrolytic solution Put one in the bottomed metal case and fix the lead leads connected to both electrode bodies to the inner ends of the external terminals attached to the insulating sealing body. The opening of the tube is sealed with a sealing body.
[0003]
However, since the current capacity of the lead is small, it is impossible to take out a large current instantaneously. Therefore, the current collector is made wider than the sheet-shaped polarizable electrode and a lead is provided. A dry battery type electric double layer capacitor has been proposed in which the protruding lead portion is swaged so as to be in surface contact as a lead surface (Japanese Patent Laid-Open No. 4-152616 and Japanese Patent Application No. 9- No. 96516).
[0004]
For example, the upper edge portion of the anode current collector and the lower edge portion of the cathode current collector are protruded lead portions protruding from the sheet-like polarizable electrode and the separator, respectively. The anode and cathode current collectors are placed facing each other, and a separator is interposed between them and wound to form a capacitor element, and then both protruding lead portions are swaged. The anode lead surface is formed on the upper surface of the capacitor element, and the cathode lead surface is formed on the lower surface. Such a capacitor element is impregnated with an electrolytic solution and then housed in a metal case. A terminal plate in surface contact with the anode lead surface is disposed on the anode lead surface side. The protruding portion of the through hole protrudes outside through the sealing body. On the other hand, the cathode lead surface is in surface contact with the bottom of the metal case.
[0005]
[Problems to be solved by the invention]
In order to obtain a high breakdown voltage using such a dry cell type electric double layer capacitor, it is necessary to arrange a plurality of dry cell type electric double layer capacitors in series. Anode lead surface and terminal plate of one electric double layer capacitor element, metal case of the terminal plate and second electric double layer capacitor, capacitor element of the same metal case and second electric double layer capacitor Since there are many connection points such as the cathode lead surface, the equivalent series resistance (ESR) becomes high. In addition, since each electric double layer capacitor is housed in a separate metal case, the cost is high. In addition, when the number of electric double layer capacitors increases, handling such as arrangement and fixing becomes troublesome.
[0006]
An object of the present invention is to provide a large-capacity electric double layer capacitor which has a high withstand voltage, a low equivalent series resistance, is inexpensive and easy to handle.
[0007]
[Means for Solving the Problems]
In the electric double layer capacitor of the present invention, the sheet-like polarizable electrode is disposed so as to be offset from the upper side edge of the metal current collector having a wider width, and a protruding lead portion is formed below the current collector. Each of the polarizable electrodes includes an electrode body that is disposed and a polarizable electrode that is offset from the lower side edge of the current collector and that has a protruding lead portion formed above the current collector. Are arranged so as to face each other, wound or stacked, and an electrolyte is formed between the opposing electrode bodies, and the upper and lower protruding lead portions are respectively brought down inside, and lead surfaces are formed on the upper surface and the lower surface. A plurality of capacitor elements are formed through a conductive rubber sheet having conductivity only in the thickness direction and not having conductivity in the radial direction between all or a part of the respective lead surfaces. Touched and connected in series In characterized in that it is housed in the same metal case.
[0008]
In the electric double layer capacitor of the present invention, the sheet-like polarizable electrode is disposed so as to be offset from the upper side edge of at least one side of the tape-like metal current collector having a wider width than that of the current collector. An electrode body in which a protruding lead portion is formed below, and an electrode body in which a polarizable electrode is arranged to be offset from the lower side edge portion of the current collector and a protruding lead portion is formed above the current collector; However, the polarizable electrodes are arranged and wound so as to face each other, an electrolyte is formed between the opposing electrode bodies, and the upper and lower protruding lead portions are respectively brought inward by swaging. A plurality of capacitor elements each having a lead surface formed on the upper surface and the lower surface are electrically conductive only in the thickness direction and not electrically conductive in the radial direction between all or part of the respective lead surfaces. Conductive rubber Characterized in that it is housed in the same metal case connected in series state brought into surface contact through the door.
[0009]
The electrolyte is preferably a solid electrolyte or an electrolyte made of gel, but may be a liquid electrolyte.
[0010]
In addition, a terminal plate is disposed so as to face the lead surface on the upper surface of the uppermost capacitor element, and conductivity is provided only in the thickness direction between the lead surface and the terminal plate, and conductivity is provided in the radial direction. A conductive rubber sheet that is not provided may be disposed, and a protruding portion above the terminal plate may protrude through the insulating sealing body of the metal case to the outside.
[0011]
Further, a conductive rubber sheet may be disposed between the lead surface on the lower surface of the lowermost capacitor element and the bottom of the metal case.
[0012]
Further, it may be disposed conductive spring member to the conductive rubber sheet and co no conductivity in the radial direction has conductivity only in the thickness direction between the capacitor elements.
[0013]
Furthermore, between the lead surface on the upper surface of the uppermost capacitor element and the terminal plate disposed so as to face the conductive rubber, the conductive rubber has conductivity only in the thickness direction and no conductivity in the radial direction. A conductive spring member is disposed with or without the conductive rubber sheet, and (or) between the lead surface on the lower surface of the lowermost capacitor element and the bottom of the metal case, with the conductive rubber sheet, Alternatively, a conductive spring member may be disposed without the conductive rubber sheet.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a sectional view showing an example of an electric double layer capacitor according to the present invention, and FIG. 2 is a view showing a part of the capacitor element unrolled. As shown in FIG. 2, the capacitor element 2 is formed by winding a cathode side electrode body 3 and an anode side electrode body 4 with separators 5 and 6 interposed therebetween.
[0015]
The cathode side electrode body 3 is formed by, for example, electrically bonding a sheet-like polarizable electrode 3b having a thickness of 400 to 800 μm to both surfaces of a tape-like current collector 3a made of an aluminum foil having a thickness of 20 to 100 μm, for example. It consists of what is pasted together with an agent. For example, the polarizable electrode is obtained by kneading activated carbon, carbon and polytetrafluoroethylene (PTFE) as a binder into a sheet shape. The current collector 3a may be a metal plate-like body or a mesh-like body in addition to the foil.
[0016]
The current collector 3a is wider than the polarizable electrode 3b, and the polarizable electrode 3b is disposed along the upper edge side of the current collector 3a. Therefore, the polarizable electrode is disposed on the lower edge side of the current collector 3a. An overhanging lead portion 3c that protrudes from the electrode 3b is formed.
[0017]
On the other hand, the anode-side electrode body 4 conducts, for example, a sheet-shaped polarizable electrode 4b having a thickness of 400 to 800 μm on both surfaces of a tape-like current collector 4a made of an aluminum foil having a thickness of 20 to 100 μm, for example. It consists of what was pasted together with adhesive. The polarizable electrode is, for example, made into a sheet by kneading activated carbon, carbon and polytetrafluoroethylene (PTFE) as a binder. In addition to the foil, the current collector 4a may be a metal plate or network.
[0018]
The current collector 4a is wider than the polarizable electrode 4b, and the polarizable electrode 4b is disposed along the lower edge side of the current collector 4a. A protruding lead portion 4c that protrudes from the electrode 4b is formed.
[0019]
In FIG. 2, the polarizable electrodes 3b and 4b of the cathode side electrode body 3 and the anode side electrode body 4 are provided on both surfaces of the current collectors 3a and 4a, respectively, but may be provided only on one side.
[0020]
The separators 5 and 6 are made of, for example, a sheet made of polypropylene or manila hemp having a thickness of 50 to 200 μm, and are wider than the polarizable electrodes 3b and 4b, but narrower than the current collectors 3a and 4a. Has been made.
[0021]
The cathode side electrode body 3 and the anode side electrode body 4 are disposed such that the polarizable electrode 3b and the polarizable electrode 4b face each other, and the separators 5 and 6 are disposed therebetween. At this time, the protruding lead portion 3c of the cathode side electrode body 3 is below the lower edge of the separators 5 and 6, and the protruding lead portion 4c of the anode side electrode body 4 is the separator 5, 6 so that it protrudes above the upper edge of 6.
[0022]
Thereafter, the cathode-side electrode body 3 and the anode-side electrode body 4 are wound and the outer periphery is stopped with a tape 2g to form the capacitor element 2. Thereafter, an electrolyte is formed between the electrode bodies 3 and 4 facing each other with the separators 5 and 6 interposed therebetween. It is preferable that the separators 5 and 6 are carbonized before forming the electrolyte. As the electrolyte, a solid electrolyte, for example, an organic semiconductor such as TCNQ (tetracyanoquinodimethane), a conductive polymer electrolyte such as polypyrrole, or the like can be used. These are impregnated into the capacitor element in a liquid or monomer state, and then formed into a solid electrolyte by cooling or polymerization. Furthermore, instead of the solid electrolyte, an electrolyte made of gel or a liquid electrolyte may be used.
[0023]
Next, the protruding lead portions 3c and 4c are swaged so as to fall inward toward the center of the capacitor element 2, respectively. By this swaging process, a lead surface (anode lead surface) 7 is formed on the upper surface of the capacitor element 2, and a lead surface (cathode lead surface) 8 is formed on the lower surface.
[0024]
As shown in FIG. 1, in the electric double layer capacitor 1 of the present invention, six such capacitor elements 2 are in surface contact with a conductive rubber sheet 16 in between, and are connected in series to form a bottomed cylindrical body made of aluminum. Is housed in a vertically long metal case 10 made of
[0025]
A conductive rubber sheet 16 is disposed on the anode lead surface 7 on the upper surface of the uppermost capacitor element 2a, and an aluminum terminal plate 12 is disposed thereon. A lead bar 12a protrudes from the center of the terminal plate 12, and the lead bar 12a passes through an insulating sealing member 13 that seals the opening above the metal case 10. It protrudes to the outside. The sealing body 13 is made of, for example, rubber or phenol resin.
[0026]
In the vicinity of the opening of the metal case 10, a lateral throttle groove 14 is formed in the metal case 10 in order to lock the sealing body 13, and after the sealing body 13 is placed on the horizontal throttle groove 14. The sealing body 13 is fixed by curling the opening edge 10a of the metal case 10 inward. In order to enhance the sealing performance, the open end edge 10a of the curled metal case enters the annular rubber portion 13a in which the sealing body 13 is provided. Further, a sleeve 15 made of a heat-shrinkable synthetic resin is covered on the outside of the metal case 10 except for a part of the central portion of the bottom surface.
[0027]
The anode lead surface 7 on the upper surface of the uppermost capacitor element 2 a is in surface contact with the conductive rubber sheet 16 disposed between the terminal plate 12 and the conductive rubber sheet is in surface contact with the terminal plate 12. It is connected. The cathode lead surface 8 on the lower surface of the lowermost capacitor element 2f is in surface contact with and connected to the bottom 11 of the metal case 10 with a conductive rubber sheet interposed therebetween.
[0028]
The conductive rubber sheet 16 is approximately the same size as the anode lead surface 7 and the cathode lead surface 8, but may be smaller or larger so as to contact the metal case 10. . However, in this case, the peripheral portion of the conductive rubber sheet 16 in contact with the metal case 10 needs to be non-conductive. The thickness of the conductive rubber sheet 16 is, for example, about 0.5 mm to 1.0 mm. A conductive rubber sheet may be used that has conductivity only in the thickness direction and does not have conductivity in the radial direction.
[0029]
The conductive rubber sheet 16 may not be disposed between all the capacitor elements, but may be disposed only between a part. Further, the lead surface (cathode lead) between the anode lead surface 7 on the upper surface of the uppermost capacitor element 2a and the aluminum terminal plate 12 disposed thereon or the lower surface of the lowermost capacitor element 2f. The conductive rubber sheet may not be disposed between the surface 8 and the bottom 11 of the metal case 10.
[0030]
A conductive adhesive may be used at each surface contact location such as between the lead surface of the capacitor element and the conductive rubber sheet to ensure contact.
[0031]
Further, between the capacitor elements, between the anode lead surface 7 on the upper surface of the uppermost capacitor element and the terminal plate 12, and on the lead surface (cathode lead surface) 8 on the lower surface of the lowermost capacitor element 2f. A conductive spring member such as a metal disc spring may be interposed between the metal case 10 and the bottom 11 of the metal case 10 with or without the conductive rubber sheet.
[0032]
The number of capacitor elements 2 accommodated in the metal case 10 is not limited to six, and may be more or less.
[0033]
【Example】
All six capacitor elements (diameter 80mm, length 30mm) rated 2.5V800F, in which lead surfaces are formed on the upper and lower surfaces in an aluminum bottomed case with a diameter of 89mm and a length of 190mm, An electric double layer capacitor having a rating of 12V130F was prepared by interposing a conductive rubber sheet (thickness: 1.0 mm) between them and storing them in series connection. The same conductive rubber is also provided between the anode lead surface on the upper surface of the uppermost capacitor element and the terminal plate and between the cathode lead surface on the lower surface of the lowermost capacitor element and the bottom of the metal case. A sheet was placed. The equivalent series resistance of this electric double layer capacitor was measured and found to be 80 mΩ.
[0034]
For comparison, when an equivalent series resistance was measured by connecting six electric double layer capacitors each having a rated 2.5 V 800 F capacitor element housed in a metal case in series, it was 483 mΩ.
[0035]
【The invention's effect】
According to the present invention, a plurality of capacitor elements having lead surfaces formed on the upper surface and the lower surface are brought into surface contact with a conductive rubber sheet interposed therebetween, and are connected in series and housed in a metal case. Therefore, an electric double layer capacitor having a high withstand voltage and a low equivalent series resistance housed in one case (metal case) can be obtained. In addition, it is easy to handle and use because it is contained in one case. Further, the cost can be reduced as compared with the case where each capacitor element is individually accommodated in a metal case.
[0036]
Also, no lead or external terminals are required, and a large current can be taken out. Further, it is not necessary to weld the drawer leads and the external terminals to each other, and the assembly work can be made more efficient.
[0037]
Electrical contact is made between the capacitor elements, between the terminal plate and the capacitor element, and between the bottom surface of the metal case and the capacitor element connected to the conductive rubber sheet. Is securely held.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an electric double layer capacitor of the present invention.
FIG. 2 shows a capacitor element.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Electric double layer capacitor 2 (2a-2f) Capacitor element 3 Electrode body (cathode side electrode body)
3a Current collector 3b Polarized electrode 3c Protruding lead part 4 Electrode body (anode side electrode body)
4a Current collector 4b Polarized electrode 4c Projection lead 5 Separator 6 Separator 7 Lead surface (anode lead surface)
8 Lead surface (cathode lead surface)
DESCRIPTION OF SYMBOLS 10 Metal case 10a Opening edge 11 Bottom part 12 Terminal board 12a Lead bar 13 Sealing body 13a Annular rubber part 14 Lateral throttle groove 15 Sleeve 16 Conductive rubber sheet

Claims (8)

An electrode body in which a sheet-like polarizable electrode is arranged to be offset from the upper side edge of a metal current collector having a wider width and a protruding lead portion is formed below the current collector; The electrode is disposed so as to be offset from the lower side edge of the current collector, and the lead body is formed above the current collector, so that the polarizable electrodes are arranged so as to face each other and wound. The electrolyte is formed between the electrode bodies that are turned or stacked, and the upper and lower protruding lead portions are respectively brought down on the inside, and a plurality of capacitor elements in which lead surfaces are formed on the upper surface and the lower surface, Same in the state of being in series contact with each other through a conductive rubber sheet that is conductive only in the thickness direction and not in the radial direction between all or part of each lead surface. It is housed in a metal case Electric double layer capacitor it is. A sheet-like polarizable electrode is disposed at least on the upper edge of one surface of a tape-shaped metal current collector having a wider width, and a protruding lead portion is formed below the current collector. The electrode body and the electrode body in which the polarizable electrode is arranged so as to be offset from the lower side edge portion of the current collector and the protruding lead portion is formed above the current collector face each other. The electrolyte is formed between the opposing electrode bodies, and the upper and lower protruding lead portions are respectively brought down inside by swaging to form lead surfaces on the upper surface and the lower surface. A plurality of capacitor elements are brought into surface contact via conductive rubber sheets that are electrically conductive only in the thickness direction and not electrically conductive in the radial direction between all or part of the respective lead surfaces. Connected in series Electric double layer capacitor are housed in the same metal case in state. The electric double layer capacitor according to claim 1 or 2, wherein the electrolyte is a solid electrolyte. The electric double layer capacitor according to claim 1 or 2, wherein the electrolyte is an electrolyte made of gel or a liquid electrolyte. A terminal plate is disposed so as to face the lead surface on the upper surface of the uppermost capacitor element, and is electrically conductive only in the thickness direction between the lead surface and the terminal plate and not electrically conductive in the radial direction. conductive rubber sheet is disposed, the electric double layer capacitor according to claim 1-4 in which the projecting portion of the upper of the terminal plate protrudes outside through an insulating sealing body of the metal case. Electric double layer capacitor according to claim 1 to 5 in which the conductive rubber sheet between the bottom of the lower surface of the lead surface and the metal case at the bottom of the capacitor element are disposed. Electrical of claim 1-6 in which the spring member of the conductivity to the conductive rubber sheet and co no conductivity is disposed radially has conductivity only in the thickness direction between the capacitor element Double layer capacitor. Between the lead surface on the upper surface of the uppermost capacitor element and the terminal plate arranged so as to face it, together with a conductive rubber sheet that is conductive only in the thickness direction and not conductive in the radial direction Alternatively, a conductive spring member is disposed without the conductive rubber sheet, and (or) between the lead surface on the lower surface of the lowermost capacitor element and the bottom of the metal case, together with the conductive rubber sheet or conductive electric double layer capacitor according to claim 1-7 which without sexual rubber sheet is a conductive spring member is disposed.

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