JPH0349396Y2 - - Google Patents

Description

[Detailed explanation of the idea]

INDUSTRIAL APPLICATION FIELD The present invention relates to an aluminum electrolytic capacitor, and more specifically to the exterior of an aluminum electrolytic capacitor. Conventional technology Conventionally, aluminum electrolytic capacitors, which have a relatively large capacitance and are used in power rectifier circuits for computers, etc., have an insulating plate 3 on the bottom outer surface of an aluminum case 2 housing a capacitor element 1, as shown in FIG. The periphery of the insulating plate 3 and the aluminum case 2 are covered with a heat-shrinkable insulating tube 4.
It was covered with and composed of. Problems to be Solved by the Invention In the aluminum electrolytic capacitor configured as described above, the heat-shrinkable insulating tube 4 is heat-shrinked by heating and fixed to the aluminum case 2, and the heat-shrinkable insulating tube 4 is fixed to the aluminum case 2. The adhesion between the insulating tube 4 and between the aluminum case 2 and the insulating plate 3 was not perfect, and an air layer was partially present. On the other hand, in recent years there has been a strong demand for smaller size and higher performance of electronic components, and demands for smaller size and higher allowable ripple current values for aluminum electrolytic capacitors have also become stronger. Generally, when a ripple current is applied to an aluminum electrolytic capacitor, the ESR of the applied capacitor is
(equivalent series resistance) and generates heat. This generated heat reduces the lifespan of the capacitor, and if the capacitor element temperature rises by 10°C, the lifespan will be reduced by almost 1/2.
It is said that it will be 2. Therefore, it is necessary to dissipate this generated heat, but if an air layer exists as described above, this air layer has an insulating effect, making efficient heat dissipation impossible, and the element temperature of the aluminum electrolytic capacitor becomes high. It was not possible to obtain a product that was sufficiently reliable in terms of reliability. Means for Solving the Problems In order to solve the above problems, the present invention provides an aluminum electrolytic capacitor in which a capacitor element is housed in a cylindrical metal case, and the opening of the metal case is sealed using a sealing material. The aluminum electrolytic capacitor is characterized in that the outer surface of the metal case is thermally conductive and is covered with a heat-shrinkable insulating tube via a thermally conductive layer such as cartilage-like silicone grease. Effect Since silicone grease is cartilage-like, when the heat-shrinkable insulating tube is heated and contracts, it forms a layer that adheres closely to the capacitor element, and the heat generated from the capacitor element is transferred to the metal case, the thermally conductive layer such as silicone grease, and the heat-shrinkable insulating tube. Since the heat is sequentially conducted to the shrinkable insulating tube, the heat dissipation effect is improved and the allowable ripple current is increased. Embodiment Hereinafter, an embodiment of the present invention shown in FIG. 1 will be described. Figure 1 is a cross-sectional view of an aluminum electrolytic capacitor, in which 1 is a capacitor element, 2 is an aluminum case that houses the element 1, 3 is an insulating plate,
5 is a cartilage-like silicone grease layer applied to the outer surface of the aluminum case 2, and 4 is a heat-shrinkable insulating tube coated on the silicone grease layer 5. Next, based on the conventional example shown in Fig. 2 and the embodiment shown in Fig. 1, an aluminum electrolytic capacitor with a rating of 450 WV, 3300 μF, a case size of 90 mm in diameter, and 140 mm in length was manufactured, and a thermocouple was attached to the center of the capacitor element. Rated ripple current 120Hz at ambient temperature 20℃,
The table shows the results of measuring the element temperature when applying 12A and DC bias of 400V.

[Table] As is clear from the table, the heat dissipation effect of the present product is improved and the element temperature is reduced.As the temperature difference with the conventional product is 5℃, the life of the present product is It can be expected that the lifespan will be 2 ^5/10 ≒ 1.4 times longer than that of conventional products. Note that the structure of the sealing portion described above is not limited to the structure of the embodiment. Further, the heat conductive layer is not limited to silicone grease, and may be any other cartilage-like material with good heat conductivity. Effects of the invention As described above, the aluminum electrolytic capacitor of this invention has a better heat dissipation effect than conventional products, suppresses the rise in element temperature, and as a result, can extend the lifespan, increasing the reliability of aluminum electrolytic capacitors. The effect of significantly improving sex is great.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the aluminum electrolytic capacitor of the present invention, and FIG. 2 is a sectional view of a conventional aluminum electrolytic capacitor. 1: Capacitor element, 2: Aluminum case, 3: Insulating plate, 4: Heat-shrinkable insulating tube,
5: Silicone grease layer.

Claims (1)

[Scope of utility model registration request] The capacitor element is housed in a cylindrical metal case,
In an aluminum electrolytic capacitor in which the opening of the metal case is sealed using a sealing material, a heat-shrinkable insulating tube is provided on the outer surface of the metal case through a cartilage-like silicone grease layer. An aluminum electrolytic capacitor characterized by being coated with.