JP2008205345A - Capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacitor with high reliability and high sealing performance of sealing rubber, while leakage of driving electrolytic solution is prevented, with respect to the capacitor used in vehicle and the like. <P>SOLUTION: In the capacitor, a capacitor element 1, together with driving electrolytic solution, is contained in a cylindrical metal case 2 with a bottom, and an opening of the metal case 2 is sealed with a terminal plate 3 through sealing rubber 4. While the sealing rubber 4 is squeezed by compression from exterior of the metal case 2, an edge of the opening of the metal case 2 is curled to the inner diameter side of the metal case 2 so that a curled part 2c having circle arc shape in cross section is formed. A protection member 5 of the film or sheet shape with Young's modulus higher than the sealing rubber 4 is arranged at the fitting portion of the edge 2d of the curled part 2c and the sealing rubber 4. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a capacitor used for various electronic devices and in-vehicle use.

  FIG. 6 is a cross-sectional view showing the structure of this type of conventional capacitor, and FIG. 7 is an enlarged cross-sectional view of the sealing portion of the capacitor.

  In FIG. 6, reference numeral 41 denotes a substantially cylindrical capacitor element. The capacitor element 41 has a pair of positive and negative electrodes having a polarizable electrode layer on a current collector made of an aluminum foil with a separator interposed therebetween. And is wound so as to have a hollow portion 41a at the center, and has a substantially cylindrical shape. The pair of positive and negative electrodes (hereinafter, the positive electrode is an anode and the negative electrode is a cathode) are offset from each other in the direction perpendicular to the winding direction, and the anode from the upper end surface of the substantially cylindrical capacitor element 41. The cathode can be respectively taken out from the lower end face (up and down direction in FIG. 6).

  Reference numeral 42 denotes a bottomed cylindrical metal case made of aluminum. The metal case 42 is formed by fitting a protrusion 42 a provided at the center of the inner bottom surface into the hollow portion 41 a of the capacitor element 41. The capacitor element 41 is accommodated such that the lower end surface is in contact with the inner bottom surface of the metal case 42. The lower end face of the capacitor element 41 and the inner bottom face of the metal case 42 are mechanically and electrically joined by means such as laser welding at the joining portion 42b.

  Reference numeral 43 denotes a terminal plate made of aluminum and formed in a disk shape. This terminal plate 43 is formed by fitting a protrusion 43a provided at the center of the lower surface into the hollow portion 41a of the capacitor element 41. Contacted via an insulating ring 44, which will be described later, to a convex portion 42c formed on the inner peripheral surface of the metal case 42 by a concave drawing process that is disposed in the opening and applied to the outer peripheral surface of the metal case 42 over the entire circumference. Is positioned.

  Further, the lower surface of the terminal plate 43 and the upper end surface of the capacitor element 41 are mechanically and electrically joined by means such as laser welding from the surface exposed to the outside of the terminal plate 43 at the joint portion 43b.

  Further, the terminal plate 43 uses a protrusion 43c provided at the center of the surface exposed to the outside as an external terminal.

  Reference numeral 44 denotes a ring-shaped insulating ring. The insulating ring 44 is provided between the outer peripheral surface of the terminal plate 43 and the inner peripheral surface of the metal case 42, and the lower peripheral edge of the terminal plate 43 and the metal case 42. It is arrange | positioned so that it may pinch | interpose between the upper ends of the convex part 42c formed in the inner peripheral side.

In FIG. 7, reference numeral 45 denotes a ring-shaped sealing rubber made of insulating rubber.
The sealing rubber 45 is disposed on the periphery of the upper surface of the terminal plate 43, and the protrusion 43 d provided on the upper surface of the terminal plate 43 suppresses the displacement of the sealing rubber 45.

  Reference numeral 42d denotes a curled portion having an arcuate cross section formed by processing (generally referred to as curling processing) so that the opening end of the metal case 42 is wound around the inner diameter side of the metal case 42. The front end portion 42e of the curled portion 42d is disposed so as to bite into the upper surface of the sealing rubber 45. As a result, the sealing rubber 45 is compressed between the upper surface of the terminal plate 43 and the tip end portion 42e, and the sealing rubber 45 is further localized by the protrusion 43e provided on the upper surface of the terminal plate 43 opposite to the tip end portion 42e. It is the composition which compresses automatically.

  The stress of the sealing rubber 45 generated thereby ensures airtightness and prevents leakage of the driving electrolyte.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP 2006-324641 A

  In the conventional capacitor described above, when used in a harsh environment or conditions, or when a continuous life test is performed, the pressure in the metal case 42 is increased due to a rise in temperature of the driving electrolyte due to heat generation of the capacitor element 41 or gas generation. As the pressure rises, a pressure is applied to the terminal plate 43 in the outward direction. Along with this, the sealing rubber 45 disposed on the periphery of the upper surface of the terminal plate 43 is also applied with a pressure to be pressed in the external direction.

  However, in the above conventional capacitor, as shown in FIG. 7, the upper surface of the sealing rubber 45 is between the portion exposed to the outside and the inner peripheral surface 42f of the curled portion 42d although the curled portion 42d is at the upper portion. The curling portion 42d and the end portion 42e of the curled portion 42d are bitten, and the sealing rubber 45 is held so as not to be pushed out. Only the portion into which the tip end portion 42e of 42d is bitten, and the pressure on the sealing rubber 45 accompanying the increase in the internal pressure of the metal case 42 is concentrated on this portion. As a result, the front end portion 42e of the curled portion 42d excessively bites into the sealing rubber 45 and causes the sealing rubber 45 to be broken. In the worst case, the sealing rubber 45 is leaked and the sealing ability is deteriorated. It was.

  The present invention solves the above-described conventional problems, and provides a capacitor having stable sealing performance by preventing the sealing rubber from breaking and preventing the tip end of the curled portion of the metal case from excessively biting into the sealing rubber. For the purpose.

  In order to solve the above-described problems, the present invention is a capacitor in which a capacitor element is housed in a bottomed cylindrical metal case together with a driving electrolyte, and the opening of the metal case is sealed with a terminal plate via a sealing rubber. And the end of the opening of the metal case is curled so as to form an arc-shaped curl section on the inner diameter side of the metal case. In this configuration, a film-like or sheet-like protective member having a higher Young's modulus than the sealing rubber is disposed at the contact portion between the tip of the curled portion and the sealing rubber.

  As described above, the capacitor according to the present invention includes a film-like or sheet-like protective member having a higher Young's modulus than the sealing rubber at the contact portion between the tip end portion of the curled portion and the sealing rubber. Even if the stress generated in the sealing rubber is concentrated on the tip of the curled part when the sealing rubber is pushed to the curled part when the pressure increases, the tip of the curled part does not bite into the top surface of the sealing rubber. Thus, the rubber can be prevented from being broken, thereby achieving an effect of realizing a highly reliable capacitor in which the driving electrolyte does not leak.

(Embodiment 1)
Hereinafter, the first embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a configuration of an electric double layer capacitor as an example of a capacitor according to Embodiment 1 of the present invention, and FIG. 2 is an enlarged cross-sectional view of a sealing portion of the electric double layer capacitor.

  In FIG. 1, reference numeral 1 denotes a substantially cylindrical capacitor element. The capacitor element 1 includes a pair of positive and negative electrodes having a polarizable electrode layer made of a carbon material on a current collector made of an aluminum foil. It is laminated with a separator interposed therebetween, and is wound so as to have a hollow portion 1a at the center, and has a substantially cylindrical shape.

  The pair of positive and negative electrodes (hereinafter, the positive electrode is an anode and the negative electrode is a cathode) are shifted from each other in the direction perpendicular to the winding direction, and the anode is formed from the upper end face of the substantially cylindrical capacitor element 1. The cathode can be respectively taken out from the lower end face (up and down direction in FIG. 1).

  Reference numeral 2 denotes an aluminum bottomed cylindrical metal case. The metal case 2 accommodates the capacitor element 1 such that the lower end surface of the capacitor element 1 is in contact with the inner bottom surface of the metal case 2. In addition, the inner bottom surface of the metal case 2 and the lower end surface of the capacitor element 1 are mechanically and electrically joined at the joint portion 2a by means such as laser welding.

  Further, an external terminal may be separately attached to the outer surface of the metal case 2 by means such as laser welding.

  In addition, a protrusion may be additionally provided at the center of the inner bottom surface of the metal case 2 (not shown), and the protrusion may be fitted into the hollow portion 1a of the capacitor element 1 to assist the fixing of the capacitor element 1. .

  Reference numeral 3 denotes a terminal plate made of aluminum and formed in a disk shape. The terminal plate 3 is formed on the metal case 2 so that the lower surface is in contact with the upper end surface of the capacitor element 1 housed in the metal case 2. It arrange | positions in the opening part and the outer peripheral surface of the terminal board 3 and the metal case 2 inner peripheral surface are insulated by the sealing rubber 4 mentioned later.

  The lower surface of the terminal plate 3 and the upper end surface of the capacitor element 1 are mechanically and electrically joined by means such as laser welding from the surface exposed to the outside of the terminal plate 3 at the joint portion 3a.

  Further, another protrusion may be additionally provided at the center of the lower surface of the terminal plate 3 (not shown), and if this protrusion is fitted into the hollow portion 1a of the capacitor element 1, the metal case 2 is provided inside. The fixing of the capacitor element 1 can be assisted.

  Further, the protrusion 3 b at the center of the surface exposed to the outside of the terminal board 3 is provided as a strength reinforcing part of the terminal board 3 or an external terminal. An external terminal (not shown) may be separately attached to the surface exposed to the outside of the terminal plate 3 by means such as laser welding.

  In FIG. 2, reference numeral 4 denotes a ring-shaped sealing rubber made of insulating rubber. The sealing rubber 4 includes a protrusion 3 c provided on the upper surface of the terminal plate 3 in the vertical direction and the lower end of the terminal plate 3. It is fitted so as to be in contact with both the flange portions 3 d provided in the horizontal direction at the periphery, and the outer peripheral surface of the terminal plate 3 and the inner peripheral surface of the metal case 2 are insulated.

  The sealing rubber 4 is made of butyl rubber (isobutylene isoprene rubber) or the like.

  Further, the sealing rubber 4 includes a protrusion 2 b formed on the inner peripheral surface of the metal case 2 and a protrusion provided on the terminal plate 3 by a concave drawing process performed over the entire outer periphery of the metal case 2. It compresses between 3c, the opening part of the metal case 2 is sealed by this, and airtightness is ensured.

  Further, reference numeral 2c denotes a curled portion having an arc-shaped cross section formed by processing (generally referred to as curling processing) so that the opening end portion of the metal case 2 is wound around the inner diameter side of the metal case 2. The leading end of the portion 2 c is shown, and the leading end 2 d comes into contact with the upper surface of the sealing rubber 4.

  Reference numeral 5 denotes a protective member having a Young's modulus higher than that of the sealing rubber 4, and is disposed at a contact portion between the tip portion 2 d of the curled portion 2 c and the upper surface of the sealing rubber 4.

  Examples of the material of the protective member 5 include modified polypropylene (modified PP), polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), and tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer. Polymer (PFA), fluorinated ethylene propylene copolymer (FEP), polyvinylidene fluoride (PVDF), ethylene-tetrafluoroethylene copolymer (ETFE), polytetrafluoroethylene (PTFE), polybutylene terephthalate (PBT), etc. Any material having a higher Young's modulus than the sealing rubber 4 may be used.

  Further, the protective member 5 may be provided on the upper surface of the sealing rubber 4 by a method such as application of the resin material as described above, or a sheet-like material may be attached to the upper surface of the sealing rubber 4.

  In FIG. 1, a metal material may be used for the protective member 5, but the terminal plate 3 in which the sealing rubber 4 is fitted is made of a metal material made of aluminum, and the terminal plate 3 is formed at the joint portion 3 a. Since it is joined to the upper end face of the capacitor element 1, when a conductive material is applied to the protective member 5, it is necessary to dispose the protective member 5 so as not to contact the terminal plate 3.

  In the above configuration, when the sealing rubber 4 is pushed toward the curled portion 2c due to the pressure increase in the metal case 2, and the stress generated in the sealing rubber 4 is concentrated on the tip portion 2d of the curled portion 2c, By arranging a film-like or sheet-like protective member 5 having a Young's modulus higher than that of the sealing rubber 4 at the contact portion with the sealing rubber 4, this protective member 5 serves as a barrier, and the sealing rubber 4 of the tip 2d. It acts so as to reduce the biting into the sealing rubber, can suppress breakage due to local excessive elongation of the sealing rubber 4, and can improve the sealing capability and improve the reliability.

  In addition, since the protective member 5 is provided, it is possible to prevent the position of the sealing rubber 4 from being displaced by preventing the front end portion 2d of the curled portion 2c from biting into the top surface of the sealing rubber 4 when the pressure in the metal case 2 increases. As a result, it is possible to reduce mechanical stress on the capacitor element 1 that is directly bonded to the terminal plate 3 combined with the sealing rubber 4 and the bonding portion 3a, and to prevent short circuit and disconnection, and reliability of electrical characteristics. Can be improved.

  In addition, the airtightness in the sealing of the opening of the metal case 2 is such that the convex portion 2b formed on the inner peripheral surface of the metal case 2 by a concave drawing process performed over the entire outer periphery of the metal case 2 The curling portion 2c is secured by compressing the sealing rubber 4 between the protruding portion 3c provided on the terminal plate 3 and the rubber 4 is pressed by the pressure applied to the sealing rubber 4 when the pressure in the metal case 2 rises. The curled portion 2c may be brought into contact with the upper surface of the sealing rubber 4 so as to prevent it from being pushed out to the outside. Accordingly, unlike the conventional capacitor shown in FIG. 6, it is not necessary to bite the tip end portion 42e of the curled portion 42d into the upper surface of the sealing rubber 45 so as to ensure airtightness. 1 can reduce the biting of the tip 2d of the curled portion 2c into the sealing rubber 4 and further suppress the breakage of the sealing rubber 4 due to excessive local elongation. The sealing ability can be increased.

  In addition, when the pressure in the metal case 2 rises, the terminal plate 3 is made of a metal material made of aluminum against the stress that tends to warp the terminal plate 3 to the outside. Yes. For this reason, the protective member 5 provided on the upper surface of the sealing rubber 4 fitted to the outer peripheral portion of the terminal board 3 prevents the tip portion 2d of the curled portion 2c from excessively biting into the upper surface of the sealing rubber 4. It is only necessary to prevent 4 from breaking. Therefore, the protective member 5 does not need a thickness or area that is necessary for the purpose of reinforcing the warp of the terminal plate 3, and may be a simple film or sheet, and the tip of the curled portion is a sealing rubber. What is necessary is just to be arrange | positioned in the local part which is contact | abutting.

  In the configuration of the electric double layer capacitor which is an example of the capacitor in the first embodiment, the anode is taken out from the upper end face and the cathode is taken out from the lower end face of the capacitor element 1 shown in FIG. The cathode may be taken out from the upper end face of 1, and the anode may be taken out from the lower end face.

(Embodiment 2)
Hereinafter, the second aspect of the present invention will be described with reference to the drawings. In addition, about what has the structure similar to the structure of Embodiment 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted, and only a different part is demonstrated using drawing below.

  FIG. 3 is an enlarged cross-sectional view of the sealing portion of the capacitor according to Embodiment 2 of the present invention. In FIG. 3, the difference from the first embodiment is that a concave portion 14a is provided on the upper surface portion of the sealing rubber 14 with which the tip portion 12d of the curled portion 12c contacts, and the protective member 15 is fixed in the concave portion 14a. Is a point. The method of fixing the protective member 15 into the recess 14a is performed by fitting or injecting in a liquid and solidifying.

  In the configuration as described above, by providing the concave portion 14a, it is easy to align the protective member 15 accurately, workability can be improved, and the tip portion 12d is excessively disposed on the upper surface of the sealing rubber 14. It is possible to surely prevent the bite from entering, and the sealing ability can be made more reliable.

(Embodiment 3)
Hereinafter, the third embodiment of the present invention will be described with reference to the drawings. In addition, about what has the structure similar to the structure of Embodiment 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted, and only a different part is demonstrated using drawing below.

  FIG. 4 is an enlarged cross-sectional view of the sealing portion of the capacitor according to Embodiment 3 of the present invention. In FIG. 4, the difference from the first embodiment is that a tip 22d of a curled portion 22c is disposed inside a recess 24a provided on the upper surface of the sealing rubber 24, and a liquid resin as a protective member 25 is provided in the recess 24a. The solidified protective member 25 is fixed to the upper surface of the sealing rubber 24 together with the tip 22d.

  In the configuration as described above, when the curled portion 22c is formed by curling, even if the position of the tip 22d of the curled portion 22c varies due to the accuracy of the curling or the dimensional variation of the metal case 22, the tip The protection member 25 can be fixed to the upper surface of the sealing rubber 24 together with 22d, and the tip portion 22d can be surely prevented from biting into the upper surface of the sealing rubber 24, and the sealing ability can be made more reliable.

(Embodiment 4)
Hereinafter, the fourth embodiment of the present invention will be described with reference to the drawings. In addition, about what has the structure similar to the structure of Embodiment 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted, and only a different part is demonstrated using drawing below.
FIG. 5 is an enlarged cross-sectional view of the sealing portion of the capacitor according to Embodiment 4 of the present invention. In FIG. 5, the difference from the first embodiment is that the front end portion 32 d of the curled portion 32 c is covered with the protective member 35 made of resin instead of providing the protective member 35 on the upper surface of the sealing rubber 34. Is a point.

  In addition, the protective member 35 has a leading end of the opening end of the metal case 32 (the leading end 32d of the curling portion 32c by curling) before the end of the opening of the metal case 32 is curled to form the curled portion 32c. And is solidified by applying a liquid resin and solidifying it.

  In the above configuration, when the protective member 35 is provided on the upper surface of the sealing rubber 34, the position of the protective member 35 needs to be adjusted so that it is between the tip 32d of the curled portion 32c and the upper surface of the sealing rubber 34. However, when the curl portion 32c is formed by curling, the tip of the opening end of the metal case 32 is previously covered with the protective member 35 so as to be integrated. Even if the position of the tip portion 32d of the curled portion 32c varies due to variations or the like, it is not necessary to align the protective member 35, so that the workability can be improved and the tip portion 32d is placed on the upper surface of the sealing rubber 34. A capacitor having high sealing ability can be obtained without excessive biting.

  In addition, when the shape of the tip end portion 32d has a generally arcuate cross section, the shape of the protective member 35 covering the tip end portion 32d is an arc cross section having a larger radius than the tip end portion 32d. The effect of preventing the tip 32d from excessively biting into the upper surface of the sealing rubber 34 can be enhanced.

  The capacitor according to the present invention has a film-like or sheet-like protective member having a Young's modulus higher than that of the sealing rubber at the contact portion between the tip of the curled portion and the sealing rubber, so that when the pressure in the metal case increases. Even if the sealing rubber is pushed toward the curled portion and the stress generated in the sealing rubber is concentrated on the tip of the curled portion, the tip of the curled portion does not bite into the sealing rubber to prevent the sealing rubber from breaking. This has the effect of realizing a highly reliable capacitor in which the driving electrolyte does not leak, and is useful as various electronic devices and in-vehicle capacitors.

Sectional drawing of the capacitor in Embodiment 1 of this invention The cross-sectional enlarged view of the sealing part of the capacitor in Embodiment 1 of this invention The cross-sectional enlarged view of the sealing part of the capacitor in Embodiment 2 of this invention The cross-sectional enlarged view of the sealing part of the capacitor in Embodiment 3 of this invention The cross-sectional enlarged view of the sealing part of the capacitor in Embodiment 4 of this invention Cross-sectional view of a conventional capacitor Cross-sectional enlarged view of the sealing part of a conventional capacitor

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Capacitor element 1a Hollow part 2,12,22,32 Metal case 2a Joint part 2b, 12b, 22b, 32b Convex part 2c, 12c, 22c, 32c Curl part 2d, 12d, 22d, 32d Tip part 3 Terminal board 3a Joint Portion 3b Protruding portion 3c Protruding portion 3d Flange portion 4, 14, 24, 34 Sealing rubber 14a, 24a Recessed portion 5, 15, 25, 35 Protection member

Claims (4)

A capacitor element in which a pair of positive and negative sheet-like electrodes are wound with a separator interposed therebetween, the capacitor element is accommodated together with a driving electrolyte, and a bottomed cylindrical metal case in which one electrode is joined, In a capacitor comprising a terminal plate in which an opening of a metal case is sealed with a sealing rubber and the other electrode is joined, the sealing rubber is squeezed from the outside so as to compress the sealing rubber, and the metal case The end of the opening is curled toward the inner diameter side of the metal case to form a curled portion having a circular arc cross section, and a film or sheet having a higher Young's modulus than the sealing rubber at the abutting portion between the tip of the curled portion and the sealing rubber A capacitor, characterized in that a protective member in a shape is arranged. The capacitor according to claim 1, wherein a concave portion is provided in an upper surface portion of the sealing rubber with which the tip portion of the curled portion abuts, and a protective member is fixed in the concave portion. A concave portion is provided in the upper surface portion of the sealing rubber with which the tip portion of the curled portion abuts. The capacitor according to claim 1, which is fixed inside. The capacitor according to claim 1, wherein a tip portion of the curled portion is covered with a protective member.

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