JP3631771B2 - Aluminum electrolytic capacitor and manufacturing method thereof - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to an aluminum electrolytic capacitor, and more particularly to a structure on the sealing portion side.
[0002]
[Prior art]
As shown in FIG. 2, an aluminum electrolytic capacitor (hereinafter referred to as an electrolytic capacitor) has a capacitor element 50 impregnated with an electrolytic solution housed in an aluminum case 51 so that the electrolytic solution does not evaporate. The open end side of the aluminum case 51 is sealed with a rubber packing 52 (elastic sealing body). Here, the rubber packing 52 is made of a material having low gas permeability such as butyl rubber in order to suppress permeation of the electrolytic solution.
[0003]
[Problems to be solved by the invention]
However, in the conventional electrolytic capacitor, when an electrolytic solution active against rubber packing, for example, a quaternary ammonium salt / γ-butyrolactone-based electrolytic solution is used for the purpose of reducing impedance, the lead of the rubber packing 52 is used. In the gap between the inner peripheral surface of the lead hole 521 and the outer peripheral surface of the lead wire 53, gamma-butyrolactone crawls up by capillary action, and the inner peripheral surface of the lead lead hole 521 swells. Further, the inner peripheral surface of the lead extraction hole 521 deteriorates due to the influence of ions attracted to the potential of the lead wire 53. For this reason, there is a problem in that the electrolyte solution may leak from the lead extraction hole 53 due to a slight variation in the size of the lateral throttle portion 511 with respect to the aluminum case 51 that fixes the rubber packing 53 or stress applied to the lead wire 53. is there.
[0004]
In view of the above problems, the object of the present invention is to improve the structure of the interface between the lead lead hole of the sealing body and the lead wire, and to prevent the occurrence of liquid leakage even when an active electrolytic solution is used. The object is to provide a high aluminum electrolytic capacitor.
[0005]
[Means for Solving the Problems]
In order to solve the above-described problems, in the present invention, an elastic sealing body in which a lead wire protrudes from an end face of a capacitor element impregnated with a γ-butyrolactone-based electrolyte and the like and the lead wire is inserted into a lead lead hole is a capacitor case. An aluminum electrolytic capacitor (hereinafter referred to as an electrolytic capacitor) which is fixed by a lateral throttle portion and an upper throttle portion with respect to a capacitor case on the open end side, and in which the end face of the elastic sealing body and the end face of the capacitor element are disposed close to each other In this case, a resin layer in an adhesive state is provided on the outer peripheral surface of the round bar portion between the inner peripheral surface of the lead extraction hole and the round bar portion of the lead wire at least in a region corresponding to the horizontal throttle portion. The resin layer is made of any one of polyvinyl alcohol, polyamide, and fluororesin. Fat is a chemical high stability insulating resin to solvents and solutes used in the electrolyte of the electrolytic capacitor.
[0006]
In an electrolytic capacitor having such a structure, before assembling the electrolytic capacitor, a manufacturing method in which a resin layer is formed on a lead wire protruding from the capacitor element, or a capacitor element is formed using a lead wire formed with a resin layer. Adopt the manufacturing method.
[0007]
For example, after the round bar part liquid resin should constitute the resin layer on the outer peripheral surface of the lead wire was coated and cured the liquid resin, said by inserting the lead wire to the lead extracting aperture capacitor The elastic sealing body is attached to the element.
[0008]
In the present invention, the resin layer is preferably adhered to both the inner peripheral surface of the lead lead hole and the outer peripheral surface of the round bar portion of the lead wire.
[0009]
In the method of manufacturing an electrolytic capacitor having such a configuration, a liquid resin that should form the resin layer is applied to at least one of the inner peripheral surface of the lead lead hole and the outer peripheral surface of the round bar portion of the lead wire, this before the resin is cured, after attaching the elastic sealing body in the capacitor element by inserting the lead wire to the lead extracting aperture, hardening the liquid resin.
[0010]
[Action]
In the electrolytic capacitor according to the present invention, since a resin layer having high chemical resistance is formed between the lead extraction hole and the lead wire, the electrolytic solution crawls up on the inner peripheral surface of the lead extraction hole. since there is no gap, the inner peripheral surface of the lead drawer holes, swelling Shinano physician. Also, the inner peripheral surface of the lead extracting aperture, so not in contact with the lead wire, is not degraded by the ion in the electrolyte solution which is attracted by the potential of the lead. Therefore, liquid leakage due to deterioration of the inner peripheral surface of the lead extraction hole can be prevented.
[0011]
【Example】
Next, embodiments of the present invention will be described with reference to the accompanying drawings.
[0012]
[Example 1]
FIG. 1 is a longitudinal sectional view of the electrolytic capacitor of this example.
[0013]
The electrolytic capacitor 10 of this example is an aluminum electrolytic capacitor with a rating of 10 Wv and a length of 15 μm, and is impregnated with an electrolytic solution in which tetramethylammonium phthalate is dissolved in γ-butyrolactone (main solvent). The capacitor element 3, lead lead holes 2 a and 2 b through which the two lead wires 4 and 5 pass, and a 3 mm-thick elastic sealing body 2 (rubber packing), and the elastic sealing body 2 were sealed. And an aluminum case 6. The elastic sealing body 2 is fixed on the open end side of the aluminum case 6 by the lateral throttle portion 6 a and the upper throttle portion 6 b of the aluminum case 6, and seals the capacitor element 3 inside the aluminum case 6. The lead wires 4 and 5 have aluminum portions 4a and 5a called round bar portions on the capacitor element 3 side, and CP wires 4b and 5b on the tip side thereof.
[0014]
The electrolytic capacitor 10 of this example has chemical resistance formed on the outer peripheral surface side of the aluminum portions 4a and 5a between the inner peripheral surfaces of the lead extraction holes 2a and 2b and the outer peripheral surfaces of the aluminum portions 4a and 5a. Resin layers 11a and 11b made of high-polyvinyl alcohol. Here, the resin layers 11a and 11b may be formed at least in the central part of the aluminum parts 4a and 5a corresponding to the lateral throttle part 6a, but in this example, the resin layer is formed on the entire aluminum parts 4a and 5a. 11a and 11b are formed.
[0015]
In the electrolytic capacitor 10 configured as described above, the elastic sealing body 2 pressed from the side surface by the lateral throttle portion 6a is not directly pressed against the outer peripheral surface of the aluminum portions 4a and 5a of the lead wires 4 and 5, but resin The layers 11a and 11b are in pressure contact with the outer peripheral surfaces. For this reason, since the adhesiveness between the inner peripheral surfaces of the lead extraction holes 2a and 2b and the outer peripheral surfaces of the resin layers 11a and 11b is high, the electrolyte does not easily crawl into the gaps due to capillary action. Therefore, the inner peripheral surfaces of the lead extraction holes 2a and 2b are not easily swollen by the solvent component (γ-butyrolactone) of the electrolytic solution. Even when there is a change in dimensions or when stress is applied to the lead wires 4 and 5, the electrolytic solution does not leak from the lead extraction holes 2a and 2b, so the reliability of the electrolytic capacitor 10 is high.
[0016]
Moreover, since the outer peripheral surfaces of the aluminum portions 4a and 5a are covered with the resin layers 11a and 11b, even when a potential is applied to the lead wires 4 and 5, quaternary ammonium ions and the like are not attracted. Accordingly, the inner peripheral surfaces of the lead extraction holes 2a and 2b are not deteriorated by ions in the electrolytic solution.
[0017]
The electrolytic capacitor 10 having such a configuration can be manufactured by a manufacturing method described below.
[0018]
First, the capacitor element 3 is manufactured using the lead wires 4 and 5 in which the resin layers 11a and 11b are formed on the outer peripheral surfaces of the aluminum portions 4a and 5a. Here, application | coating of the polyvinyl alcohol resin to the outer peripheral surface of aluminum part 4a, 5a is performed by letting the lead wires 4 and 5 pass between the rotors which rotate, for example, and resin is hardened after that.
[0019]
Next, after impregnating the capacitor element 3 with the electrolytic solution, the lead wires 4 and 5 are inserted into the lead extraction holes 2 a and 2 b, and the elastic sealing body 2 is attached to the capacitor element 3.
[0020]
Next, the capacitor element 3 is stored in the capacitor case 6.
[0021]
Thereafter, the elastic throttle body 2 is fixed by providing the horizontal throttle portion 6a and the upper throttle portion 6b to the capacitor case 6.
[0022]
According to this manufacturing method, since the resin layers 11a and 11b can be formed in the state of the lead wires 4 and 5, they can be easily handled.
[0023]
In addition, after forming the capacitor | condenser element 3 using a normal lead wire, you may form the resin layers 11a and 11b in the outer peripheral surface of the aluminum parts 4a and 5a which protrude from the end surface.
[0024]
In the above embodiment, polyvinyl alcohol resin was used as the resin layer provided between the inner peripheral surface of the lead extraction hole and the outer peripheral surface of the lead wire. Fluorine resin such as ethylene-6-fluoropropylene copolymer, 4-fluoroethylene-perfluoroalkoxyethylene copolymer, 4-fluoroethylene-ethylene copolymer, vinylidene fluoride, or polyamide resin may be used. In addition, these resins have high chemical stability against the solvent and solute used in the electrolytic solution of the electrolytic capacitor.
[0025]
[Example 2]
Since the basic configuration of the electrolytic capacitor of this example is the same as that of the electrolytic capacitor according to the first embodiment, the corresponding parts are denoted by the same reference numerals and will be described with reference to FIG. In FIG. 1, the electrolytic capacitor 30 of this example also includes the resin layers 31a and 31b having high chemical resistance between the lead extraction holes 2a and 2b and the aluminum portions 4a and 5a of the lead wires 4 and 5. Have. Here, the resin layers 31a and 31b are in a state of being bonded to both the inner peripheral surfaces of the lead lead holes 2a and 2b and the outer peripheral surfaces of the outer peripheral surfaces of the aluminum portions 4a and 5a of the lead wires 4 and 5.
[0026]
For this reason, the lead extraction holes 2a and 2b are completely sealed, and there is no gap inside. Therefore, the electrolyte does not creep up to the lead extraction holes 2a and 2b and the quaternary ammonium ions are not attracted to the aluminum portions 4a and 5a, so that the electrolyte does not leak.
[0027]
In the electrolytic capacitor 30 having such a configuration, a liquid resin is applied to the inner peripheral surfaces of the lead extraction holes 2a and 2b or the outer peripheral surfaces of the aluminum portions 4a and 5a of the lead wires 4 and 5 before the assembly process. Can be manufactured.
[0028]
For example, in the method of manufacturing the electrolytic capacitor 30 of this example, first, the liquid resin is applied to the outer peripheral surfaces of the aluminum portions 4a and 5a. Here, in the aluminum parts 4a and 5a, there is a step part at the boundary between the round bar part and the flat part where the foil is located. In this example, current is concentrated on the step part so that ions are not concentrated. The resin is also applied to the step portion.
[0029]
Next, before the resin is cured, the lead wires 4 and 5 are inserted into the lead extraction holes 2 a and 2 b to attach the elastic sealing body 2 to the capacitor element 3.
[0030]
Next, the capacitor element 3 is stored in the capacitor case 6.
[0031]
Next, the elastic sealing body 2 is fixed by the lateral throttle part 6 a and the upper throttle part 6 b of the capacitor case 6.
[0032]
Thereafter, the resin is cured.
[0033]
As a result, the cured resin (resin layers 31a and 31b) is adhered to both the inner peripheral surface and the aluminum portions 4a and 5a inside the lead extraction holes 2a and 2b.
[0034]
【The invention's effect】
As described above, in the electrolytic capacitor according to the present invention, the resin layer in an adhesive state is provided on the outer peripheral surface of the round bar portion between the inner peripheral surface of the lead lead hole and the outer peripheral surface of the round bar portion of the lead wire. The resin layer is characterized by being made of polyvinyl alcohol, polyamide, and fluororesin . Therefore, according to the present invention, the electrolyte does not crawl on the inner peripheral surface of the lead extraction hole, and ions in the electrolytic solution are formed on the inner peripheral surface of the lead extraction hole by the potential applied to the lead wire. Since it is not attracted, the inner peripheral surface of the lead extraction hole does not deteriorate. Therefore, leakage of the electrolytic solution can be prevented, and the reliability of the electrolytic capacitor can be improved.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a configuration of an electrolytic capacitor according to Embodiments 1 and 2 of the present invention.
FIG. 2 is a longitudinal sectional view showing a configuration of a conventional electrolytic capacitor.
[Explanation of symbols]
10, 30 ... Electrolytic capacitors (aluminum electrolytic capacitors)
2 ... Elastic sealing body 2a, 2b ... Lead extraction hole 3 ... Capacitor element 4, 5 ... Lead wire 4a, 4b ... Aluminum part 6 ... Aluminum case 6a ... Horizontal aperture Part 11a, 11b, 31a, 31b ... resin layer

Claims (4)

The lead wire protrudes from the end face of the capacitor element impregnated with the electrolyte, and the elastic sealing body in which the lead wire is inserted into the lead extraction hole is fixed at the open end side of the capacitor case by the lateral restricting portion and the upper restricting portion with respect to the capacitor case. In the aluminum electrolytic capacitor in which the end face of the elastic sealing body and the end face of the capacitor element are arranged close to each other, at least the inner peripheral surface of the lead extraction hole and the lead wire in the region corresponding to the lateral throttle portion Between the round bar part, having a resin layer in an adhesive state on the outer peripheral surface of the round bar part,
The aluminum electrolytic capacitor, wherein the resin layer is made of any one of polyvinyl alcohol, polyamide, and fluororesin. 2. The aluminum electrolytic capacitor according to claim 1, wherein the resin layer is bonded to both an inner peripheral surface of the lead lead hole and an outer peripheral surface of the round bar portion of the lead wire. A method for producing an aluminum electrolytic capacitor as defined in claim 1,
After the leads the round bar part liquid resin should constitute the resin layer on the outer peripheral surface of the coating was cured the liquid resin,
A method for producing an aluminum electrolytic capacitor, wherein the lead wire is inserted into the lead lead hole and the elastic sealing body is attached to the capacitor element. A method for producing an aluminum electrolytic capacitor as defined in claim 2 ,
Applying a liquid resin to form the resin layer to at least one of the inner peripheral surface of the lead extraction hole and the outer peripheral surface of the round bar portion of the lead wire, and before the resin is cured, the lead wire is After attaching the elastic sealing body to the capacitor element through the lead lead hole,
A method for producing an aluminum electrolytic capacitor, wherein the liquid resin is cured.

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