JPH07122466A - Electrolytic capacitor - Google Patents

Abstract

PURPOSE:To provide an electrolytic capacitor capable of preventing corrosion and dissolution breakdown of a sealing member which are to be caused by alkali generated in a case. CONSTITUTION:A capacitor element 1 which is dipped in electrolyte 4 is contained in a metal bottomed cylindrical case 6. The aperture part 7 of a case 6 is sealed by using a sealing member 8. A fluororesin plate 9 having corrosion resistance is laid on the part of the sealing member 8 which part is in contact with the electrolyte 4. A seal ring 10 is laid on the part of the case 6 which part is in contact with the inner peripheral surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic capacitor.

[0002]

2. Description of the Related Art Generally, an electrolytic capacitor has a capacitor element in which an anode foil connected to a plus electrode and a cathode foil attached to a minus electrode are wound together with electrolytic paper. As shown in FIG. 6, the capacitor element 19 is housed in a case 18 made of aluminum whose one end is open, while being immersed in the electrolytic solution 25. Then, conventionally, a sealing member 20 made of rubber as an elastic body is fitted into the opening 26 of the case 18.

The plus and minus electrodes 21, 22 of the capacitor element 19 and the lead wires 23 connected to the electrodes 21, 22 are inserted into a pair of holes 24 formed in the sealing member 20. And case 18
By caulking the opening 26, the case 18 and the sealing member 20 are brought into close contact with each other, and the sealing member 20 and the electrodes 21, 22 and the lead wire 23 are brought into close contact with each other to seal the inside of the case 18. Was there.

By the way, depending on the kind of solvent constituting the electrolytic solution, the sealing member swells and dissolves, and the holes 24
May expand or expand, or the caulked part may have poor adhesion to the case. In such a case, the electrolyte solution 25 leaks to the outside from the hole 24 or the outer periphery of the sealing member 20, or air is mixed into the electrolyte solution 25, and the function as the capacitor is impaired. Therefore, a special rubber having excellent solvent resistance is often selected as the sealing member 20.

[0005]

However, in the conventional structure, the electrolytic solution 25 and the sealing member 20 are in contact with each other, and when this electrolytic capacitor is used by incorporating it into an electric circuit or the like, it is included in the electrolytic solution 25. Positive ions of matter,
Negative ions have electrodes 21 and 22 of opposite polarities
Gather to the side. Therefore, the negative electrode 22 side becomes a strong alkali, and even if the sealing member 20 is a special rubber as described above, the strong alkali causes the rubber in the vicinity of the hole 24 around the electrode 22 and the lead wire 23 to be remarkably dissolved and destroyed, and There is a risk that the liquid leakage phenomenon may occur or air may be mixed.

Further, among the various kneading materials (polymer itself, filler, reinforcing agent, cross-linking agent, etc.) contained in the sealing member 20, they are eluted into the electrolytic solution 25 to be ionized, and each is similarly electrophoresed. There is a risk that the lead wires 23 may be corroded and broken by being gathered on the electrodes 21 and 22 having opposite polarities.

Further, the rubber itself has a property of permeating a gasified solvent. For this reason, peroxide-crosslinked butyl rubber, which is said to have the least gas permeability of the elastic body, is used as the sealing member for important functional and high-performance capacitors. I cannot escape.

Further, when the sealing member is only rubber, the sealing member moves due to vibration or other external stress when the electrolytic capacitor is incorporated in an electric circuit of an automobile, for example, and the sealing is incomplete. In some cases, the function may not be exhibited. Therefore, in such a case, a step of attaching a Bakelite plate on the sealing member or fixing the rubber and the lead wire with an epoxy resin or the like is performed. Therefore, in such a case, the process of manufacturing the electrolytic capacitor becomes complicated.

The present invention has been made by paying attention to the problems existing in the above-mentioned prior art, and the purpose thereof is to prevent corrosion and dissolution destruction of the sealing member and prevent liquid leakage and disconnection. Moreover, it is to provide an electrolytic capacitor that is easy to manufacture.

[0010]

In order to achieve the above object, according to the present invention, a metal case having a bottom and a bottom is provided.
A capacitor element is housed in a state of being immersed in an electrolytic solution, and in an electrolytic capacitor in which the opening of the case is sealed by a sealing member, a corrosion-resistant member having corrosion resistance in a portion in contact with the electrolytic solution of the sealing member, An elastic member is provided at a portion in contact with the inner peripheral surface of the case.

Further, in the present invention, an annular groove is provided on the outer peripheral surface of the corrosion resistant member, and the elastic member is provided in the groove. Further, in the present invention, the opening of the case is sealed by caulking the case.

Further, in the present invention, the corrosion resistant member is a fluororesin having chemical resistance, solvent resistance and permeation resistance, and the elastic member is butyl rubber.

[0013]

In the electrolytic capacitor constructed as described above, a corrosion-resistant member having physical properties such as chemical resistance, solvent resistance, and permeation resistance is provided on the inner periphery of the case at the portion of the sealing member that comes into contact with the electrolytic solution. An elastic member was provided at the portion in contact with the surface. Therefore, when the electrolytic capacitor of the present invention is used by incorporating it into an electric circuit or the like, even if a strong alkali is generated in the electrode of the electrolytic capacitor, the elastic member is not corroded or dissolved and destroyed.

Further, since the elastic member is provided only in the annular groove on the outer peripheral surface of the corrosion resistant member, it is easy to manufacture.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the electrolytic capacitor of the present invention will be described in detail below with reference to FIGS.

As shown in FIG. 1, the capacitor element 1 is
An anode foil (not shown) attached to the plus electrode 2 and a cathode foil (not shown) attached to the minus electrode 3 are wound together with electrolytic paper (not shown). Lead wires 5 are connected to both electrodes 2 and 3, respectively.

The case 6 made of aluminum is in the shape of a bottomed cylinder having an opening 7 on one side, and the capacitor element 1 is inserted in the interior thereof while being immersed in the electrolytic solution 4.

As shown in FIGS. 1 to 4, the sealing member 8 is made of a fluorine resin plate 9 as a corrosion-resistant member having chemical resistance, solvent resistance, and permeation resistance and butyl rubber as an elastic member. It is composed of a seal ring 10. The fluororesin plate 9 has a disk shape having substantially the same diameter as the opening 7,
A concave portion 11 as an annular groove is formed on the circumferential surface of the fluororesin plate 9.
Are formed all around. The seal ring 10 is formed in a shape similar to the shape of the recess 11,
It is fitted in the recess 11. A pair of holes 12 are formed in the fluororesin plate 9. A part of the hole 12 is a recess 11
It has an opening at the bottom.

Then, the electrode 2 of the capacitor element 1,
3 and the lead wire 5 are inserted into the hole 12 of the sealing member 8. The vicinity of the opening 7 of the case 6 is crimped. At this time, since the seal ring 10 is disposed at the crimping position, the elasticity of the seal ring 10 ensures that the seal ring 10 and the inner peripheral surface of the case 6 are in close contact with each other. Due to this close contact, the opening 7 of the case 6 is sealed. Further, the inner peripheral portion of the seal ring 10 is formed by caulking the inner peripheral surface of the hole 12, the electrodes 2, 3 and the lead wire 5.
Be in close contact with. Due to this close contact, the hole 12 is sealed.

In the electrolytic capacitor constructed as described above, the fluororesin plate 9 serving as a corrosion-resistant member having physical properties such that the contact between the electrolytic solution 4 and the seal ring 10 is chemical resistance, solvent resistance and permeation resistance. Has been cut off by. For this reason,
When the electrolytic capacitor of the present embodiment is used by incorporating it in an electric circuit or the like, even if, for example, the periphery of the negative electrode 3 becomes a strong alkali, the seal ring 10 is not corroded or dissolved and destroyed. Therefore, it is possible to reliably prevent the liquid leakage phenomenon and the mixing of air. Further, since the fluororesin plate 9 has stable physical properties, a part thereof does not elute into the electrolytic solution 4, and the lead wire 5 does not corrode or break due to the eluted ions.

Further, in the state where the seal ring 10 is arranged at the crimping position, the vicinity of the opening 7 of the case 6 is crimped,
The elasticity of the seal ring 10 ensures that the seal ring 10 and the inner peripheral surface of the case 6 are in close contact with each other.
Is sealed. In this case, since the fluorine resin plate 9 having no gas permeability blocks the surface of the electrolytic solution 4, the case 6 is completely sealed, and even if the electrolytic solution 4 is vaporized, It is possible to prevent escape from the inside of 6. Therefore, the electrolytic capacitor of this embodiment can be used for important functions.

In addition, since the sealing member 8 is composed mainly of the fluororesin plate 9, unlike the case where the entire sealing member is made of rubber, it has high rigidity. Therefore, even if the electrolytic capacitor of this embodiment is used for the vibrating portion, it does not move from the predetermined position. Therefore, a bonding step such as bonding a bakelite plate or bonding a rubber and a lead wire with an epoxy resin or the like is not necessary, and the manufacturing is easy.

Further, in the process of manufacturing the electrolytic capacitor of this embodiment, particularly in the process of caulking the opening 7,
The fluororesin plate 9 serves as a reinforcement. Therefore, even if the caulking force is not uniformly applied to the vicinity of the opening 7 for some reason, the deformation of the case 6 can be suppressed, and the number of defective products generated in the manufacturing process can be reduced.

The present invention is not limited to the above embodiments, but can be carried out in the following modes without departing from the spirit of the present invention. (1) As shown in FIG. 5, the hole 12 should be arranged apart from the recess 11. In this case, the caulking force acting on the sealing member 8 deforms the fluororesin plate 9 so that the inner peripheral surface of the hole 12 comes into close contact with both electrodes 2, 3 and the lead wire 5, and the hole 12
Is sealed. (2) Apply tin plating to the outer peripheral surfaces of both electrodes 2 and 3 and lead wire 5. With this configuration, the seal ring 1
The seal ring 10 is bonded to the outer peripheral surfaces of the electrodes 2 and 3 and the lead wire 5 by vulcanization molding for 0. Therefore, for example, in the above-described embodiment, both electrodes 2,
3 and the lead wire 5 are inserted, and in that state, the seal ring 1
If the vulcanization molding of 0 is performed, reliable adhesion between the hole 12 and the electrodes 2, 3 and the lead wire 5 can be obtained. (3) As the seal ring 10, use a rubber other than butyl rubber, for example, a rubber such as nitrile rubber that does not change with time. (4) Use a material other than the fluororesin 9, such as an epoxy resin, as a corrosion-resistant member having physical properties such as chemical resistance, solvent resistance, and permeation resistance. (5) The seal ring 10 is provided by filling the annular recess 11 by injection molding.

[0025]

In the electrolytic capacitor of the present invention configured as described above, when the electrolytic capacitor is used by incorporating it in an electric circuit or the like, for example, even if a strong alkali is generated around the electrodes, the sealing member is formed. Can be prevented from being corroded, dissolved and destroyed, or eluted into the electrolytic solution. Therefore, it is possible to prevent liquid leakage, air intrusion, or corrosion breakage of the lead wire. Further, the inside of the case is completely sealed, gas generated in the case can be prevented from escaping from the case, and the electrolytic capacitor can be used as an important functional and high performance electrolytic capacitor. Furthermore, since the movement of the sealing member can be prevented,
No treatment is required for that, and the manufacturing is simplified.

[Brief description of drawings]

FIG. 1 is a cutaway view showing an embodiment of an electrolytic capacitor embodying the present invention.

FIG. 2 is a front view showing a sealing member.

FIG. 3 is a cross-sectional view showing the shape of a fluororesin plate that constitutes a sealing member in an electrolytic capacitor.

FIG. 4 is a cross-sectional view showing the shape of a seal ring that constitutes a sealing member in an electrolytic capacitor.

FIG. 5 is a front view showing another example of the sealing member in the present invention.

FIG. 6 is a cutaway view showing a conventional electrolytic capacitor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Capacitor element, 4 ... Electrolyte, 6 ... Case, 7 ... Opening, 8 ... Sealing member, 9 ... Fluororesin plate as a corrosion-resistant member having physical properties of chemical resistance, solvent resistance and permeation resistance 1
0 ... Seal ring as elastic member, 11 ... Recess as annular groove

Claims (4)

[Claims] 1. An electrolytic capacitor in which a capacitor element is housed in a metal case having a bottom and is immersed in an electrolytic solution, and an opening of the case is sealed with a sealing member. The electrolytic capacitor according to claim 1 or 2, wherein a corrosion-resistant member having corrosion resistance is provided in a portion in contact with the electrolytic solution, and an elastic member is provided in a portion in contact with the inner peripheral surface of the case. 2. The electrolytic capacitor according to claim 1, wherein an annular groove is provided on the outer peripheral surface of the corrosion resistant member, and the elastic member is provided in the groove. 3. The electrolytic capacitor according to claim 1, wherein the opening of the case is sealed by caulking the case. 4. The electrolytic capacitor according to claim 1, wherein the corrosion-resistant member is fluororesin and the elastic member is butyl rubber.