JP2759928B2 - Aging method for electrolytic capacitors - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to an improvement in an aging method for an electrolytic capacitor.

[Prior art]

The electrolytic capacitor uses a so-called valve metal having an insulating oxide film formed on the surface thereof, such as aluminum, tantalum, or niobium, as an anode, and uses the insulating oxide film as a dielectric layer, as well as a cathode for current collection. A capacitor element is formed by interposing an electrolytic solution between the electrodes, the capacitor element is housed in an outer case such as a metal or synthetic resin case, and the opening of the outer case is sealed with a sealing member. The insulating oxide film forming the dielectric layer of the electrolytic capacitor oxidizes the valve metal surface of the anode as a base material by a processing operation such as an anodic oxidation reaction to form an extremely thin dielectric layer. The characteristics of electrolytic capacitors are their small size and large capacity.The reason for this is that the oxide film layer that forms the dielectric layer is extremely thin, for example, aluminum, about 12 mm per volt, and the relative dielectric constant is more than ten or more. It depends. However, since the dielectric layer is thin, the dielectric layer may be damaged due to mechanical damage in the assembly process of the electrolytic capacitor after the formation of the dielectric layer. When the anode is cut into a predetermined size after the formation of the dielectric layer on the anode surface, the cut surface may not include the dielectric layer. When such a damaged portion or an unformed portion of the dielectric layer is used as an electrolytic capacitor, a leakage current flows through this portion, and the electrical characteristics of the electrolytic capacitor are significantly impaired. The electrolyte impregnated inside the capacitor element directly contacts the dielectric layer and functions as a true cathode,
A local anodic oxidation reaction is caused in a defective portion of the dielectric layer, and the function of repairing and forming the oxide film layer is taken. As described above, the electrolytic capacitor has a large leakage current at the time of assembling and cannot be put to practical use as it is. Therefore, after the assembling, the aging process is usually performed also for debugging of the electrolytic capacitor. The aging process is performed by raising the temperature of the electrolytic capacitor to a range of room temperature or the maximum operating temperature, and applying a DC voltage until a voltage rises from a constant current or constant voltage source to a rated voltage or a surge voltage for a predetermined time. . Thereby, the damaged portion of the oxide film as the dielectric layer,
Alternatively, in the unformed portion, the anodic oxidation reaction proceeds due to the internal electrolytic solution, an oxide film layer is formed, and with this formation, the leakage current gradually decreases, and aging is terminated when the leakage current value becomes equal to or less than a specified leakage current value. .

[Problems to be solved by the invention]

By the way, what is done by heating the aging process is
This is for accelerating the repair reaction of the oxide film layer and completing the aging treatment in a short time. As a heating method at the time of the conventional aging treatment, in the case of the badge treatment, an electrolytic capacitor is attached to an energizing jig and stored in a constant temperature bath covered with a heat insulating material, and the electrolytic capacitor is raised to a predetermined temperature. After that, aging is performed. In the case of a continuous production line, a constant-temperature bath is arranged in a tunnel shape during the process of continuously transferring the electrolytic capacitor by a chain, a belt conveyor, or the like, and the temperature is controlled while the electrolytic capacitor is transferred in the constant-temperature bath. Aging. As means for raising the temperature in the thermostatic bath, a heating means such as a heater is provided in the bath, and the temperature of the electrolytic capacitor is raised by direct radiant heat or convection by blowing air. However, this conventional method has a drawback that it takes time to raise the temperature of the electrolytic capacitor body, and the aging process is prolonged. In addition, since a certain space in the thermostat must be heated, there is a drawback that there is much waste such as power consumption. An object of the present invention is to improve such a conventional drawback and to provide an aging method for efficiently aging an electrolytic capacitor in a short time.

Means for Solving the Problems According to the present invention, an electrolytic capacitor containing a capacitor element impregnated with an electrolyte inside an exterior member is irradiated with microwaves to increase the temperature of the capacitor element. Aging is performed by applying a DC voltage to an electrolytic capacitor. That is, according to the present invention, the heating of the electrolytic capacitor main body in the aging step is performed by microwave irradiation, and the heated electrolytic capacitor is aged by applying a DC voltage according to a conventional method.

[Action]

According to the present invention, by irradiating the electrolytic capacitor with microwaves, rotation of a small amount of water molecules contained in the electrolytic solution impregnated inside the capacitor element, heat generated due to friction caused by collision, and heat generated inside the capacitor element. Can be raised in temperature. Microwaves are obtained by irradiating a high frequency of about 2.45 GHz from an oscillating element such as a magnetron. In an electrolytic capacitor, a capacitor element is usually housed in a bottomed cylindrical outer case made of aluminum or the like. Microwaves are usually reflected from metal and are not irradiated from the outer case surface to the inside. However, since the sealing portion is made of an elastic rubber member or the like, the microwave is normally irradiated into the inside of the capacitor element through the sealing portion to generate heat and increase the temperature. When the outer case is made of a synthetic resin or the like, the microwave penetrates into the inside from the outer case surface, so that the irradiation time or the irradiation energy can be shortened or reduced.

【Example】

Hereinafter, the present invention will be described based on examples. FIG. 1 schematically shows an apparatus for performing continuous aging according to the present invention. In the figure, an electrolytic capacitor 1 is obtained by impregnating an electrolytic solution into a capacitor element in which an anode electrode, a cathode electrode, and a separator are superimposed and wound in an outer case in an assembling process in a previous stage, and the opening of the outer case is closed. It is sealed with an elastic member. Further, external leads 2 and 3 extending from the inside through the elastic member are attached. This electrolytic capacitor 1 is used in an aging process.
Attached to the aging jig 4. Aging jig 4
In the figure, an insulating plate member 5 is provided upright at the center, and external leads 2 and 3 of the electrolytic capacitor 1 are inserted into both side surfaces so as to straddle the plate member 5. Contact terminals 6 and 7 made of a metal plate having a spring property are attached to the side surfaces of the plate-like member 5. The external leads 2 and 3 are sandwiched by the elastic force of the contact terminals 6 and 7, and the electrolytic capacitor 1 is mounted. Is fixed to the aging jig 4. The contact terminals 6 and 7 fix the electrolytic capacitor 1, and each has an electrical connection with the outside, and is connected to an external DC power supply (not shown), and applies a DC voltage for aging to the electrolytic capacitor 1. ing. The aging jig 4 has a shape that is continuous in the vertical direction in the drawing, and a plurality of electrolytic capacitors 1 are continuously attached. The aging jig 4 is attached to a transfer device 8 such as a belt conveyor, a chain, or the like, and is sequentially moved to enable continuous processing. The electrolytic capacitor 1 subjected to the heating aging process is irradiated with microwaves from the magnetron 10 when passing through the inside of the shield case 9 for preventing the diffusion of microwaves made of a metal punching metal, etc. The temperature rises. Reference numeral 11 denotes a high-frequency power supply for driving the magnetron 10. As a microwave irradiation method, continuous irradiation may be used to raise the temperature to a predetermined temperature at once, or divided irradiation may be performed for a short time. Further, since the temperature of the electrolytic capacitor once heated gradually decreases after the irradiation of the microwave is completed, a method of re-irradiating the electrolytic capacitor after a predetermined time can be selected. In order to prevent the temperature of the electrolytic capacitor from lowering, the outside of the shield case 9 may be covered with a heat insulating material. Next, the change in temperature rise between the method of the present invention and the case where the temperature was raised in a conventional thermostat was examined. The electrolytic capacitor used has a rated voltage of 50 V and a rated capacitance of 1000 μF.
The capacitor element has a cylindrical shape with a length of 25 mm and a length of 25 mm. The capacitor element uses a wound element, and has a structure in which a set of an anode lead and a cathode lead is drawn out from one end face from one end face. As the outer case, a bottomed cylindrical aluminum case is used, and the opening is sealed with elastic rubber. The tip of the probe of the optical fiber thermometer was buried in the center of the capacitor element of this electrolytic capacitor, and the temperature change was observed. Then, the manner in which the temperature of the capacitor element rose to 85 ° C. was recorded. According to the method of the present invention, an electrolytic capacitor is arranged on a fixed base at ordinary room temperature, the irradiation position of the magnetron is arranged so as to face the sealing body of the electrolytic capacitor, and the outer periphery of the electrolytic capacitor is made of punching metal. It was covered and shielded to prevent microwaves from leaking outside. Microwave irradiation conditions are: oscillation frequency 2.45 GHz, output
Continuous irradiation was performed using a 500 W power supply. On the other hand, as a conventional example, an electrolytic capacitor of the same rating was housed in a hot-air circulation type thermostat, and the temperature rise was examined. In this thermostatic bath, warm air heated by a heater is circulated in the bath using a fan, and the hot air is blown at about 90 ° C. These temperature changes are shown in the graph of FIG. As is clear from this graph, in the case of using the method of the present invention, the temperature of the capacitor element rose to the predetermined 85 ° C. in only 3 minutes and 30 seconds. On the other hand, in the conventional method using a constant temperature bath, it took 21 minutes to rise to 85 ° C.

【The invention's effect】

As described above, according to the present invention, when heating and aging an electrolytic capacitor, the element of the electrolytic capacitor can be raised to a predetermined temperature and aged in an extremely short time. For this reason, the time of the aging process can be shortened, and the manufacturing efficiency of the electrolytic capacitor can be improved. In addition, since only the capacitor element is heated, a huge thermostat facility is not required unlike the related art, and there is no need to use extra power for heating.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing an aging apparatus used in the aging method of the present invention, and FIG. 2 is a graph showing a rise in temperature inside an electrolytic capacitor according to the present invention and a conventional method. DESCRIPTION OF SYMBOLS 1 ... Electrolytic capacitor, 2,3 ... External lead 4 ... Aging jig, 5 ... Plate member 6,7 ... Contact terminal, 8 ... Transfer device 9 ... Shield case, 10 ... Magnetron 11 …… High frequency power supply

Claims (1)

(57) [Claims] An electrolytic capacitor comprising a capacitor element impregnated with an electrolytic solution inside an exterior member is irradiated with microwaves to increase the temperature of the capacitor element.
An aging method for an electrolytic capacitor, wherein aging is performed by applying a DC voltage to the electrolytic capacitor.