JPS6040178B2 - Method of manufacturing metallized film capacitors - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a metallized film cosodenser, in which an element is formed by winding a metallized film in which a metallized film is formed on both sides or one side of a display film. be.

In the case of this type of capacitor, the electrode extraction portion is an important point in terms of characteristics.

Generally, both end faces of the capacitor element (electrode extraction part)
Electrodes are formed on both end faces of the capacitor element by arc spraying metal. When such a capacitor is used in an AC circuit of 100 V or more for electrical equipment, a problem arises due to the heat generation phenomenon caused by the rise in dielectric tan6.When the internal temperature of the capacitor rises in this way, the plastic Deterioration of the film, reduction in withstand voltage, etc. will occur, and in the worst case, the capacitor will be destroyed.

Furthermore, if there is an insufficient bond between the capacitor element and the metallicon, deterioration of tan6 begins to occur at that point, and in wound type capacitors,
The location where the adhesion with the metallicon is weak is at the winding core where irregular winding is likely to occur. That is, as shown in FIG.
When a high current is passed through a capacitor that has a weak point 4 where the adhesion is weak, the metal vapor deposited film 2 on the electrode extraction part of the weak point 4
is burnt out, and the current cannot flow directly from the burnt out part 5 to the intermediate part 6, so it flows through the electrode part 7, which overloads the electrode part 7. When a current surge is applied, the electrode The metal vapor deposited film 2 in the portion 7 is burned away one after another.

If the metal vapor deposited film 2 of the electrode portion 7 is burnt out in this manner, the contact resistance per unit area increases, and the tan6 value as a capacitor also increases. Furthermore, as the contact resistance increases, the generation of Joule heat also increases and the internal temperature of the capacitor rises. In order to prevent such a temperature rise, it is necessary to
As shown in FIG. 2, if the burned out part 8 of the metal vapor deposited film 2 is provided in the direction perpendicular to the length direction of the film, concentration of current will not occur, and the metal vapor deposited film 2 of the electrode part 7 as described above This prevents the fire from burning out one after another, and prevents the temperature from rising.

Further, in order to cause the metal hollyhocks deposited film 2 to be burned away in the perpendicular direction, the metal evaporated film 2 should have a weak point 9. The present invention has been made in view of the current situation, and in the present invention, the heating step is necessary to shape, that is, harden, the capacitor element.

The heating temperature at this time must take into consideration the heat resistance and heat shrinkage of the polypropylene or polyester film that is the base film of the metallized film, and at the same time must be at a temperature at which the capacitor element after winding can be formed. Capacitor elements using polypropylene film can be molded at lower temperatures than those using polyester film, and polyester film has a higher heat resistance and less thermal shrinkage, so it can be molded at higher temperatures. According to experiments, the minimum temperature required to mold a capacitor element using polypropylene film is 60℃.
oo, and the maximum temperature is 110 oo when considering thermal contraction, deformation of the capacitor element, etc. Also, the minimum temperature at which capacitor elements using polyester film can be molded is 7.
5o0, and the maximum temperature was 140°C. In the present invention, the capacitor element is heated to a temperature of 60 qo to 14,000 quartz, which is sufficient to form a metallized film using polypropylene or polyester as a base film, and after the entire capacitor element reaches a uniform temperature,
Instantly 50k9/earth to 300k9/lump pressure 1-30
The metal vapor deposited film 2 at the bend at the beginning of the winding stretches and the film resistance increases, as shown in Figures 1 and 2.
A weak point 9 as shown in the figure is formed. In this molding method, the heating time is the time required for the entire capacitor element to reach a specified temperature. Therefore, the heating time and pressing time will differ depending on the thickness of the film and the thickness of the capacitor element, but since the entire capacitor element has reached the temperature at which it can be molded, the pressure will be applied uniformly to the entire capacitor element, regardless of the thickness of the capacitor element. 9 is formed. In the present invention, there are two reasons for pressing the heated condenser element.

The first step is to mold the element and obtain the required capacity. The second purpose is to increase the resistance of the metal vapor deposited film at the bend at the beginning of film winding to form a weak point. The pressure required for element molding is 20 to 30 k9/ground (currently), but 50 k9/ground is sufficient.
If pressed with a pressure less than k9/lump, it will not be possible to increase the resistance of the metal vapor deposited film at the bend at the beginning of film winding.
The weak point 9 cannot be formed. Conventional polyester film capacitors are molded by heat aging at a temperature of 1150±5° C. for 14±4 hours while applying a pressure of 20 to 30 k9/min. Therefore, even though the pressure is low, the capacitor element after molding is very hard and hardly recovers from molding. However, according to this molding method, after the temperature of the entire capacitor element reaches the specified temperature,
If pressing is carried out at a pressure of less than 0 kg/1 to 30 Kg/ground, sufficient capacity can be obtained during pressing, but when the pressure is removed, forming (20 to 30 K9/Ground pressure) is not possible. However, the heat processing of the film itself is not sufficient, the hardness is inferior to conventional molded products, there is some rebound after molding, and the capacity is reduced. In order to increase the hardness of the molded element under conditions where heat aging is insufficient and to take into account recovery after molding, it is necessary to set the capacity at the time of pressing to be larger than the expected value of capacity. For that, the pressure is 50k9
/ Person in charge or above is required. When pressed at a pressure of 20 to 30 kg', the initial capacity is reduced by 3 to 5% compared to conventional molded products. Therefore, if molding is performed with less than 50k9', it is necessary to increase the electrode length in order to obtain a capacity equivalent to that of the conventional method, leading to a rise in material costs. On the other hand, 30
Pressing with a pressure exceeding 0k9/ground deteriorates the physical properties not only of the film winding start but of the entire metallized film, resulting in a shortened lifespan as a capacitor. Furthermore, in consideration of moldability, variations in capacitance, uniform pressing over the entire surface of the element, etc., it is necessary to press the capacitor elements individually. In the case of individual presses, it is better to shorten the press time in consideration of workability, manufacturing cost, etc.
As a result of considering workability, manufacturing cost, etc., the press time was 30
It turned out that the sand should be less than that. Furthermore, the pressing time varies depending on the thickness of the capacitor element. For example, in the case of a polyester film capacitor element with a thickness of 4 ribs or less, sufficient molding was possible with a press time of 1 second, and the capacity was also satisfactory. Furthermore, even when the capacitor element was thick, a sufficiently satisfactory molded element could be obtained with a pressing time of less than 30 minutes. Therefore, it was found that the pressing time should be within the range of 1 to 30 hours. Unless these conditions are satisfied, the object of the present invention cannot be achieved. According to such a manufacturing method of the present invention, it is possible to make the metallized film 2 of the metallized film have a weak point 9, and thereby, when the metallized film has a weak point 4 with weak adhesion to the metallicon layer 3, When a current load is applied and the metal vapor deposited film 2 at the weak point 4 is burned out and the current density of the electrode part 7 increases, the current density flowing to the weak point 9 of the metal vapor deposited film 2 also increases and is burned out, resulting in the state shown in FIG. No current flows through the intermediate portion 6 as shown, the current density in the current portion 7 decreases, and no rise in n6 or temperature occurs.

Further, when the adhesion of the metallicon layer 3 is sufficient, the weak point 9 of the metal vapor deposited film 2 poses no problem; even if the metal vapor deposited film 2 is burnt out, it does not pose any problem as a capacitor. Next, a specific example of the method for manufacturing a metallized film capacitor of the present invention will be described. A capacitor element with a capacitance of 5F was obtained by using a metallized film made by vapor-depositing aluminum on a polyethylene terephthalate film with a thickness of 6F, and a polypropylene film with a thickness of 5F as a laminated film, and then shaped into a flat shape. It was heated for 3 minutes in a 11,500° heating tank.

After heating for 30 minutes, take it out from the hot tub and heat it at room temperature for 100k.
Press molding was performed for 5 seconds by applying a pressure of 9/ground.

The press-molded capacitor element was then arc-sprayed with aluminum to form metallicon electrodes, and then lead wires were welded and the capacitor was covered with epoxy resin. FIG. 3 shows the charging and discharging results of the capacitor manufactured in this manner.

As is clear from the results shown in FIG. 3, although a capacitance change occurs, tan6 hardly changes.

As described above, according to the present invention, it is possible to obtain a capacitor having a capacitance that does not deteriorate tan6 and does not cause an abnormal temperature rise even when a high current load is applied.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram to explain the current path of a wound-type metallized film capacitor that has a weak point in the metallicon layer, and Figure 2 shows a metallized film capacitor in which the weak point has been removed and is now normal. FIG. 3 is a diagram showing the capacitance change and tan6 change in a charge/discharge test of a metallized film capacitor according to an embodiment of the manufacturing method of the present invention in comparison with a conventional example. be. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. A capacitor element constructed by winding a metallized film with polypropylene or polyester film as a base film is heated at a temperature of 60°C to 140°C, and the heated capacitor element is heated to a temperature of 50kg/cm^2 to 300°C.
A method for manufacturing a metallized film capacitor, which comprises forming metallized film capacitors into a flat shape by pressing at a pressure of kg/cm^2 for 1 to 300 seconds, and then providing metallized electrodes on both end faces of a capacitor element.