JP2008098545A - Capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable capacitor having high sealing performance of a sealing opening rubber for preventing leakage of electrolytic solution for drive with respect to a capacitor used for an automobile and the like. <P>SOLUTION: A capacitor includes: a capacitor element 1 having a structure, in which a pair of positive and negative electrodes are wound with a separator in between and thereby the positive and negative electrodes are dislocated in reverse directions mutually; a cylindrical metallic case 2 having a bottom for storing the capacitor element 1 and the electrolytic solution for drive; and a terminal plate 3, in which an opening of the metallic case 2 is sealed with a ring-shaped sealing opening rubber 5. The external boundary face of the sealing opening rubber 5 is extracted from outside and is contacted with the metallic case 2, while the inner boundary face of the sealing opening rubber 5 is put in contact with the terminal plate 3. At the same time, the capacitor has an inner boundary projected portion 5a projected in a central direction all around the inner boundary face of the sealing opening rubber 5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  FIG. 7 is a cross-sectional view showing the structure of this type of conventional capacitor. In FIG. 7, reference numeral 10 denotes a capacitor element, 10a denotes a hollow portion formed in the capacitor element 10, and the capacitor element 10 is made of an aluminum foil. This capacitor element is formed by winding a pair of positive and negative electrodes, each having a polarizable electrode layer formed on a current collector, shifted in opposite directions with a separator interposed therebetween (all not shown). The anode and the cathode are respectively taken out from both end faces of 10 (vertical direction in FIG. 7).

  Reference numeral 11 denotes an aluminum bottomed cylindrical metal case containing the capacitor element 10 together with a driving electrolyte (not shown), and 11a is integrally provided on the inner bottom surface so as to be fitted into the hollow portion 10a of the capacitor element 10. The projection 11a is fitted into the hollow portion 10a of the capacitor element 10 and the end face on the cathode side of the capacitor element 10 inserted into the metal case 11 is attached to the inner bottom surface of the metal case 11 by means such as laser welding. It is designed to be mechanically and electrically joined. Reference numeral 11b denotes a drawn portion having a V-shaped cross section provided on the metal case 11, and presses the peripheral edge of the upper end face of the capacitor element 10 from the outside.

  12 is an aluminum terminal plate, 12a is an anode terminal for external connection integrally provided on the outer surface side of the terminal plate 12, and 12b is a joint portion with an end surface on the anode side of the capacitor element 10 provided on the inner surface side. , 12c are protrusions that fit into the hollow portion 10a of the capacitor element 10, and are mechanically and electrically connected by joining the anode side end face of the capacitor element 10 to the joint portion 12b by means such as laser welding. It is intended to be connected to.

  Reference numeral 13 denotes an insulating ring formed in a ring shape and disposed at the upper end of the drawn portion 11 b provided on the metal case 11, and the insulating ring 13 includes the inner surface of the metal case 11 and the outer peripheral surface of the terminal plate 12. Insulation between the terminal plate 12 and the metal case 11 is maintained by connecting to a part of the inner peripheral edge of the terminal plate 12 from between.

  Reference numeral 14 denotes a ring-shaped sealing rubber made of insulating rubber, and is arranged around the surface periphery of the terminal plate 12 so as to wind the opening of the metal case 11 with the sealing rubber 14 interposed. It is configured to be sealed by processing (generally called curling processing).

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP 2000-315632 A

  However, in the above conventional capacitor, in order to prevent leakage of the driving electrolyte contained in the metal case 11 together with the capacitor element 10, the terminal plate 12 is disposed in the opening of the metal case 11, and this terminal plate 12 is sealed by curling the opening of the metal case 11 through a rubber sealing rubber 14 disposed on the periphery of the surface of the capacitor 12. However, the capacitor element 10 generates heat when used in harsh environments and conditions, or when a continuous life test is performed, and the temperature of the driving electrolyte rises accordingly. In the worst case, there is a problem that the driving electrolyte causes leakage.

  This is because the sealing rubber 14 is compressed by curling the opening of the metal case 11 and sealing is performed using the stress of the sealing rubber 14 generated thereby to prevent leakage of the driving electrolyte. However, in the curling process at this time, the opening of the metal case 11 is processed by curling, and the amount of the opening biting into the sealing rubber 14, that is, mechanical Since the curling process is performed by managing only the proper dimensions, the stress generated in the sealing rubber 14 after processing cannot be grasped at all, and the Young's modulus, elongation at break, etc. of the sealing rubber 14 As a result, the stress generated in the sealing rubber 14 after the processing varies, and in the worst case, the driving electrolyte solution is changed. One in which there has been a problem that causes the liquid.

  In order to solve such a conventional problem, an object of the present invention is to increase the sealing ability of a sealing rubber and to suppress leakage of a driving electrolyte.

  In order to achieve the above object, 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 ring-shaped sealing rubber. The outer peripheral surface of the sealing rubber is in contact with the metal case by being squeezed from the outside of the metal case, the inner peripheral surface of the sealing rubber is in contact with the terminal plate, and the inner peripheral surface of the sealing rubber An inner peripheral protrusion that protrudes toward the center over the entire periphery is provided.

  As described above, the capacitor according to the present invention enhances the sealing ability generated between the sealing rubber and the terminal board, thereby realizing a highly reliable capacitor in which the driving electrolyte does not leak. The effect that it can be obtained.

(Embodiment 1)
FIG. 1 is a cross-sectional view showing a configuration of an electric double layer capacitor according to Embodiment 1 of the present invention, and FIG.

  1 and 2, reference numeral 1 denotes a capacitor element. The capacitor element 1 has a pair of positive and negative electrodes, each having a polarizable electrode layer formed on a current collector made of aluminum foil, shifted in the opposite direction to each other. It is configured by winding with a separator interposed (all not shown), and a hollow portion 1a is formed in the center portion, and an anode and a cathode are respectively connected from both end surfaces (vertical direction in FIG. 1) of the capacitor element 1. It is something to be taken out.

  Reference numeral 2 denotes an aluminum bottomed cylindrical metal case in which the capacitor element 1 is accommodated together with a driving electrolyte (not shown). An end face on the cathode side of the capacitor element 1 accommodated in the metal case 2 (in FIG. 1). The lower surface side) is mechanically and electrically joined to the inner bottom surface of the metal case 2 by means such as laser welding. Reference numeral 2 b denotes a drawing section having a R-shaped cross section applied to the metal case 2, which is formed by narrowing from the outside of the metal case 2.

  Reference numeral 3 denotes an aluminum terminal plate having a shape in which a central portion (anode terminal 3 a) and an outer peripheral portion (sealing surface by a sealing rubber) of the flat plate protrude perpendicularly to the flat plate. The end surface on the anode side (the upper surface side in FIG. 1) is joined to the lower surface side of the terminal plate 3 by means of laser welding or the like, so as to be mechanically and electrically joined, and by the anode terminal 3a Electrically pulled out for external connection.

  Reference numeral 5 denotes a ring-shaped sealing rubber made of an insulating rubber, and is disposed on the peripheral edge of the outer peripheral portion of the terminal plate 3 as shown in FIG. The case 2 is sealed and configured by processing so as to involve the opening of the case 2 (generally called curling).

  The sealing rubber 5 may be made of a resin vulcanized rubber such as butyl rubber (isobutylene isoprene rubber), and the thickness of the ring-shaped portion of the sealing rubber 5 is preferably in the range of 2 to 4 mm. In the present embodiment, the curling process was performed using butyl rubber having a ring-like thickness of 3 mm.

  Further, as shown in FIG. 2, the outer peripheral surface of the sealing rubber 5 is in contact with the inner surface of the metal case 2 by narrowing the outer peripheral surface of the sealing rubber 5 from the outside of the metal case 2 so as to form the drawn portion 2b. The inner peripheral surface of the sealing rubber 5 is in contact with the outer peripheral portion of the terminal board 3. Furthermore, the inner peripheral surface of the sealing rubber 5 is provided with an inner peripheral protrusion 5a that protrudes toward the center over the entire periphery.

  Here, as shown in FIG. 3, the cross section of the sealing rubber 5 is such that the inner peripheral protruding portion 5 a has a substantially semicircular shape as a cross sectional shape, but is narrowed from the outside of the metal case 2 in FIG. 2. Therefore, the inner peripheral protrusion 5a does not appear in FIG.

  In this way, the sealing ability between the inner peripheral protruding portion 5a provided on the inner peripheral surface of the sealing rubber 5 and the outer peripheral portion of the terminal plate 3 is increased by being squeezed from the outside of the metal case 2 by the drawing portion 2b. The leakage of the driving electrolyte in the metal case 2 can be suppressed.

  Further, since the terminal plate 3 does not come into contact with the metal case due to the thickness of the sealing rubber 5, it is not necessary to use an insulating ring.

(Embodiment 2)
FIG. 4 is an enlarged view of a main part of the electric double layer capacitor according to the second embodiment of the present invention.

  In FIG. 4, a terminal plate 3 having a shape in which a central portion (anode terminal 3 a) and an outer peripheral portion (sealing surface by a sealing rubber) of a flat plate are projected is used. An outer peripheral protruding portion 3d is formed on the outer peripheral portion of the outer peripheral portion. The outer peripheral protruding portion 3d has a cross-sectional shape that protrudes from the center to the outer side in a substantially semicircular shape.

  The shape of the protrusion may be an outer peripheral protrusion 3e having a trapezoidal cross section as shown in FIG.

  If it does in this way, the sealing capability between the inner peripheral surface of the sealing rubber 5 and the outer peripheral protrusion part 3d provided in the outer peripheral part of the terminal board 3 will increase by being squeezed by the drawing part 2b from the outside of the metal case 2. Therefore, the leakage of the driving electrolyte inside the metal case 2 can be suppressed.

  Further, the sealing rubber 5 needs to be positioned with respect to the outer peripheral portion of the terminal plate 3 so as to be opposed to generate stress. For this purpose, a flange portion 3b of the terminal plate 3 is provided as shown in FIG. When the sealing rubber 5 is arranged so as to be in contact with the flange portion 3b for positioning or when the flange portion 3b is not provided on the terminal plate 3, the inner peripheral surface of the sealing rubber 5 as shown in FIG. The positioning portion 5b may be provided on the upper surface of the terminal board 3 for positioning.

  Further, when the positioning portion 5b is not provided on the sealing rubber 5, as shown in FIG. 6, positioning may be performed so that the upper surface of the terminal board 3 and the upper surface of the sealing rubber 5 are substantially at the same height.

  By doing so, for the purpose of sealing between the outer peripheral portion of the terminal plate 3 and the inner peripheral surface of the sealing rubber 5 when the drawing is performed so as to form the drawn portion 2b from the outside of the metal case 2. This will cause stress.

  In the above embodiment, the capacitor element 1 is an element using an electric double layer capacitor. However, it may be an element using an aluminum electrolytic capacitor.

  The state of stress for sealing in each of the above embodiments will be described in detail.

  First, between the outer peripheral surface of the sealing rubber 5 and the inner surface of the metal case 2 in the case where the inner peripheral surface of the sealing rubber 5 is provided with the inner peripheral protruding portion 5a having a semicircular cross section as in the first embodiment. The generated stress (hereinafter referred to as case side stress) and the stress generated between the inner peripheral surface of the sealing rubber 5 and the outer peripheral portion of the terminal plate 3 (hereinafter referred to as terminal plate side stress) are respectively simulated. Calculated by

  At this time, it can be said that the case-side stress and the terminal plate-side stress have the same value and a larger value indicates a higher sealing ability.

  Next, the case side stress and the terminal plate side stress of the sealing rubber 5 in the case where the outer peripheral protruding portion 3d having a semicircular cross section is provided on the outer peripheral portion of the terminal plate 3 as in the second embodiment are calculated in the same manner. did.

Further, the case-side stress and the terminal-plate-side stress of the sealing rubber 5 without the above-described inner peripheral protrusion 5a and outer peripheral protrusion 3d were calculated in the same manner. (Hereinafter referred to as Comparative Example 1)
The following results are shown in Table 1 below.

  As shown in (Table 1), the case side stress is high in Comparative Example 1, whereas the difference between the case side stress and the terminal plate side stress is small in Example 1, and is smaller in Example 2. It has become. By setting it as such a state, it can be set as a capacitor | condenser with high sealing capability of the outer peripheral surface and inner peripheral surface of the sealing rubber 5. FIG.

  Next, specific examples of the above embodiments will be described.

(Example 1)
A high-purity aluminum foil (Al: 99.99% or more) having a thickness of 30 μm was used, and the surface of the aluminum foil was roughened by electrolytic etching in a hydrochloric acid-based etching solution.

  Next, polarizable electrodes were formed on both sides of the aluminum foil. The polarizable electrode is formed by mixing a phenol resin-based activated carbon powder having an average particle diameter of 5 μm, a carbon black having an average particle diameter of 0.05 μm as a conductivity imparting agent, and a water-soluble binder solution in which CMC is dissolved in a ratio of 10: 2: 1. After mixing at a weight ratio and sufficiently kneading with a kneader, a dispersion solvent of methanol and water is added little by little to further knead to produce a paste having a predetermined viscosity, and then this paste is applied to the surface of the aluminum foil. And dried for 1 hour in air at 100 ° C. to form.

  Next, two aluminum foils on which this polarizable electrode was formed were prepared, one being a positive electrode and the other being a negative electrode, with a separator having a thickness of 35 μm interposed between the positive electrode side and the negative electrode side. And turn around. At this time, the capacitor element (winding diameter: φ30 mm) was obtained by winding while shifting the position so that the positive and negative end faces were exposed in opposite directions.

  Next, this capacitor element was impregnated with an electrolytic solution. This electrolytic solution was prepared by dissolving 4 ethylammonium boron tetrafluoride in propylene carbonate.

  Thereafter, the capacitor element is inserted into a bottomed cylindrical metal case made of aluminum, and the opening is a sealing rubber having a shape shown in FIG. 3 (thickness 2.5 mm, inner peripheral protrusion r = 1.0). And an electric double layer capacitor sealed by curling using a terminal board (capacitor external dimension: φ35 × 45 mm).

(Example 2)
In the first embodiment, the opening of the metal case is curled and sealed using a terminal plate (trapezoidal shape with an outer peripheral protrusion of 1 mm) and a sealing rubber (thickness 3 mm, no inner peripheral protrusion) shown in FIG. An electric double layer capacitor was produced in the same manner as in Example 1 except that the capacitor was stopped (capacitor outer dimension: φ35 × 45 mm).

(Comparative Example 2)
In Example 1 above, an electric double layer capacitor was produced in the same manner as in Example 1 above except that the opening of the metal case was sealed by the method shown in FIG. 7 (prior art) (capacitor external dimension: φ35 × 45 mm). ).

  For the electric double layer capacitors of Examples 1 and 2 and Comparative Example 2, initial characteristics (capacitance, DC capacitor resistance (hereinafter abbreviated as DCR)) and characteristic deterioration test when 2.3 V is applied at 85 ° C. It was. The results are shown in (Table 2). Note that the number of tests was 20. The DCR was charged and then discharged, and the slope of 0.5 to 2.0 sec at the start was calculated.

  As is clear from Table 2, the capacitance change of the electric double layer capacitor according to the present invention was smaller than that of the comparative example, and ΔC and ΔDCR in the characteristic deterioration test could be greatly improved as compared with the comparative example.

  Thus, the capacitor of 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 ring-shaped sealing rubber. The outer peripheral surface of the rubber is in contact with the metal case by being squeezed from the outside of the metal case, the inner peripheral surface of the sealing rubber is in contact with the terminal plate, and the entire circumference of the inner peripheral surface of the sealing rubber By providing an inner peripheral protrusion that protrudes toward the center, the sealing ability that occurs between the sealing rubber and the terminal plate is enhanced, thereby allowing the drive electrolyte to leak. A highly reliable capacitor can be realized.

  The capacitor according to the present invention has an effect of eliminating the leakage of the driving electrolyte and is excellent in reliability, and is particularly useful for automobiles that require high reliability.

Sectional drawing which showed the structure of the capacitor | condenser by one embodiment of this invention The principal part enlarged view of the capacitor | condenser by Embodiment 1 of this invention Cross-sectional view of the sealing rubber of the capacitor The principal part enlarged view of the capacitor | condenser by Embodiment 2 of this invention Sectional view of the capacitor terminal board The principal part enlarged view of the capacitor | condenser by Embodiment 2 of this invention Sectional view showing the structure of a conventional capacitor

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Capacitor element 2 Metal case 2b Drawing part 3 Terminal board 3a Anode terminal 3b Flange part 3d, 3e Outer periphery protrusion part 5 Sealing rubber 5a Inner periphery protrusion part 5b Positioning part

Claims (3)

A capacitor element in which a pair of positive and negative electrodes are wound with a separator interposed therebetween, and the positive and negative electrodes are shifted in opposite directions, and a bottomed cylindrical metal containing this capacitor element together with a driving electrolyte In a capacitor comprising a case and a terminal plate in which an opening of the metal case is sealed with a ring-shaped sealing rubber, an outer peripheral surface of the sealing rubber is in contact with the metal case by the metal case being squeezed from the outside. The inner peripheral surface of the sealing rubber is in contact with the terminal plate, and an inner peripheral protruding portion is provided that protrudes toward the center over the entire inner peripheral surface of the sealing rubber. Capacitor. A capacitor element in which a pair of positive and negative electrodes are wound with a separator interposed therebetween, and the positive and negative electrodes are shifted in opposite directions, and a bottomed cylindrical metal containing this capacitor element together with a driving electrolyte In a capacitor comprising a case and a terminal plate in which an opening of the metal case is sealed with a ring-shaped sealing rubber, an outer peripheral surface of the sealing rubber is in contact with the metal case by the metal case being squeezed from the outside. The inner peripheral surface of the sealing rubber is in contact with the terminal plate, and the outer peripheral protrusion protrudes outward from the center over the entire outer periphery of the terminal plate in contact with the inner peripheral surface of the sealing rubber. Capacitor characterized by having a part. The capacitor according to claim 1 or 2, wherein a cross-sectional shape of a circumferential protrusion of the sealing rubber or an outer periphery protrusion of the terminal plate has a substantially semicircular R shape or a trapezoidal shape.

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