JP2025035471A - Capacitor and manufacturing method - Google Patents

Abstract

The position of a capacitance element can be fixed, and sufficient insulation performance is ensured.
[Solution] The capacitor (1) comprises a capacitive element (10) including a pair of external terminals (13) and a wound body (11) located between the pair of electrodes, an outer container (30), a resin inner container (50) in which the capacitive element is disposed and which is located between the capacitive element and the outer container, and a second resin (40) filled in the inner container and the outer container.
[Selected Figure] Figure 1

Description

The present invention relates to a capacitor.

It is known that the performance of a capacitor's capacitance element deteriorates when water vapor and oxygen come into contact with the capacitance element. Therefore, in order to prevent performance deterioration, the capacitance element of a capacitor is molded in resin.

JP 2005-294589 A

In Patent Document 1, in order to ensure moisture resistance, the capacitance element is covered with a resin that does not contain filler, which is then cured, and the element is resin-molded into the shape of a capacitor with a resin that contains filler. However, the insulating performance of the capacitor changes depending on the position of the capacitance element relative to the capacitor container. Therefore, the insulating performance may change as the resin is injected.

One aspect of the present invention aims to arrange a capacitive element so that the capacitor has sufficient insulation performance.

In order to solve the above problems, the capacitor according to the present invention comprises a capacitive element including a pair of electrodes and a dielectric located between the pair of electrodes, an outer container, a resin inner container in which the capacitive element is disposed and which is located between the capacitive element and the outer container, and a filling resin filled in the inner container and the outer container.

In order to solve the above problems, the method for manufacturing a capacitor according to the present invention includes the steps of forming a capacitive element using a pair of electrodes and a dielectric located between the pair of electrodes, housing the capacitive element in a resin inner container, housing the inner container in an outer container, filling the inner container and the outer container with a filling resin, and hardening the filling resin.

The position of the capacitive element in the capacitor can be fixed, ensuring sufficient insulation performance.

1 is a schematic diagram showing a capacitor according to a first embodiment. 4A to 4C are model diagrams showing a manufacturing process of the capacitor according to the first embodiment. 10A to 10C are model diagrams showing a manufacturing process of a capacitor according to a second embodiment. 11A to 11C are model diagrams showing a manufacturing process of a capacitor according to embodiment 3. 11A to 11C are model diagrams showing a manufacturing process of a capacitor according to embodiment 4. FIG. 13 is a schematic diagram showing a capacitor according to a comparative example.

Comparative Example
Prior to describing the embodiment, a comparative example of a capacitor 100 will be described first. Fig. 6 is a schematic diagram showing the comparative example of a capacitor 100. The capacitor 100 includes a capacitive element 10, a first resin 20 (coating resin), an outer container 30, and a second resin 40 (filling resin).

The capacitance element 10 is an element that functions as a capacitor. The capacitance element 10 is formed by forming a metallikon electrode 12 on both end faces of a wound body 11 formed by winding a pair of metallized films, and attaching an external terminal 13 to the metallikon electrode 12. Note that the metallized film is a dielectric film on which metal is formed. The capacitance element 10 is not limited to a wound metallized film, but may be a laminate of metallized films.

The metallikon electrode 12 is formed by spraying metal, so it is not densely packed with metal, but is porous with many gaps. Therefore, oxygen and water vapor can penetrate into the wound body 11 through the gaps in the metallikon electrode 12, causing the performance of the capacitance element 10 to deteriorate.

The first resin 20 is a resin that does not contain a filler. The first resin 20 is impregnated into the capacitance element 10, and the outer periphery of the capacitance element 10 is covered and coated with the first resin. Since the first resin 20 does not contain a filler, the first resin 20 penetrates into the inside of the capacitance element 10 without any gaps, and also blocks the gaps in the metallikon electrode 12. This makes it possible to suppress the intrusion of oxygen, water vapor, and the like into the capacitance element 10. After the capacitance element 10 is covered with the first resin 20, it is cured. An example of the first resin 20 is an epoxy resin.

The outer container 30 is a metal container with only one side open. The outer container 30 houses the capacitive element 10 coated with the first resin 20 inside. The outer container 30 is then filled with the second resin 40 and sealed to produce the capacitor 100.

Here, since the specific gravity of the capacitance element 10 covered with the first resin 20 is smaller than that of the second resin 40, when the second resin 40 is being injected, the capacitance element 10 covered with the first resin 20 floats up relative to the second resin 40.

As a result, the position of the capacitance element 10 relative to the outer container 30 is not fixed, and in some cases, sufficient insulation performance may not be obtained. For example, the metallikon electrode 12 of the capacitance element 10 may come into contact with the outer container 30, causing a short circuit. In addition, since the capacitance element 10 has many cavities inside, it may have a lower specific gravity than the second resin 40. As a result, there is a high possibility that the capacitance element 10 will float when the second resin is being injected.

The second resin 40 contains a filler. Therefore, if sealing is performed using only the second resin 40 without the first resin 20, it is not possible to prevent oxygen, water vapor, and the like from entering the capacitance element 10. However, since the second resin 40 contains a filler, less heat is generated when it hardens, making it less likely to damage the capacitance element 10. An example of the second resin 40 is a urethane resin.

[Embodiment 1]
Hereinafter, an embodiment according to one aspect of the present invention (hereinafter, also referred to as "the present embodiment") will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and the description thereof will not be repeated.

(Overview of Capacitor 1)
Next, a description will be given of the capacitor 1 according to the embodiment 1. Fig. 1 is a schematic diagram showing the capacitor 1 according to the embodiment 1. The capacitor 1 includes a capacitive element 10, a first resin 20, an outer container 30, a second resin 40, and an inner container 50.

The inner container 50 is a resin container with only one side open. The inner container 50 holds the capacitive element 10 covered with the first resin 20 in an uncured state inside. The first resin 20 is then cured. As a result, the inner container 50 and the capacitive element 10 are bonded together. In other words, there is a portion between the capacitive element 10 and the inner container 50 where only the first resin 20 is present, and the two are bonded together there.

Then, the inner container 50 combined with the capacitance element 10 is housed in the outer container 30, and the inner container 50 and the outer container 30 are filled with the second resin 40 and sealed, thereby manufacturing the capacitor 1. In other words, the inner container 50 is a resin container in which the capacitance element 10 is placed and which is located between the capacitance element 10 and the outer container 30.

That is, in the capacitor 100, the first resin 20 is cured only on the capacitance element 10, whereas in the capacitor 1, the first resin 20 is cured so as to bond the capacitance element 10 and the inner container 50. As in the capacitor 100, the capacitance element 10 in the capacitor 1 is covered with the first resin 20, so that deterioration of the capacitance element 10 due to oxygen and water vapor can be prevented.

(Insulation for Capacitive Element 10)
In the capacitor 1, the capacitance element 10 is coupled to the inner container 50. Furthermore, since the capacitance element 10 is housed in the resin inner container 50, it is not in direct contact with the outer container 30. Therefore, it is easy to ensure the insulation of the capacitance element 10.

In addition, since the capacitance element 10 is bonded to the inner container 50, the position of the capacitance element 10 can be determined by placing the inner container 50 relative to the outer container 30. Furthermore, since the sides of the inner container 50 are also covered with resin, it is easy to ensure a sufficient insulation distance for the capacitance element 10 even if the positioning of the capacitance element 10 is not performed precisely.

(Anti-oxidation and moisture resistance)
The capacitance element 10 is covered with a first resin 20 that does not contain a filler, and this first resin 20 penetrates into the inside of the capacitance element 10. Therefore, there is no part of the capacitance element 10 that is in direct contact with air, and therefore it is possible to prevent the intrusion of oxygen and water vapor. In other words, there is an effect of preventing oxidation of the capacitance element 10 and improving the moisture resistance. Note that the impregnation of the capacitance element 10 with the first resin 20 is performed under a reduced pressure environment, whereby bubbles can be removed from within the capacitance element 10.

(Manufacturing process of capacitor 1)
A description will now be given of a manufacturing process of the capacitor 1 according to the embodiment 1. Fig. 2 is a model diagram showing the manufacturing process of the capacitor 1 according to the embodiment 1.

First, the capacitive element 10 is constructed (step 61). The capacitive element 10 is then immersed in a liquid tank filled with the first resin 20 and pulled out, thereby covering the capacitive element 10 with the first resin 20 (step 62). The capacitive element 10 covered with the first resin 20 is housed in the inner container 50 (step 63). The first resin 20 is then cured together with the inner container 50 and the capacitive element 10, and the inner container 50 and the capacitive element 10 are bonded together (step 64).

The joined inner container 50 is placed in the outer container 30 (step 65). The second resin 40 is first poured into the inner container 50, but not into the outer container 30 (step 66). As the pouring of the second resin 40 continues, the inner container 50 becomes full, and the second resin 40 overflows from the upper edge of the inner container 50 and enters the outer container 30 (step 67).

The second resin 40 is being poured into the outer container 30, but since the inner container 50 is already filled to the brim with the second resin 40, the weight of the inner container 50 is sufficiently heavy. The specific gravity of the inner container 50 at the height of the liquid surface of the second resin 40 in the outer container 30 is sufficiently greater than the specific gravity of the second resin 40. Therefore, the inner container 50 combined with the capacitance element 10 does not float up relative to the outer container 30, and the second resin 40 can be poured to the end (step 68). The second resin 40 is then cured together with the outer container 30 (step 69), thereby manufacturing the capacitor 1.

[Embodiment 2]
Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

In the second embodiment, the process of injecting the second resin 40 in the manufacturing process of the capacitor 1 is different from that in the first embodiment. FIG. 3 is a model diagram showing the manufacturing process of the capacitor 1 according to the second embodiment. In the manufacturing process of the capacitor 1 according to the second embodiment, steps 61 to 65 are the same as those in the first embodiment.

The second resin 40 is poured so that the liquid levels in the inner container 50 and the outer container 30 are the same (step 71). For example, the inner container 50 may have an opening or a cut through which the second resin 40 can move between the inner container 50 and the outer container 30, thereby balancing the liquid levels of both.

The second resin 40 is continued to be poured until the liquid level reaches a specified height (step 72). At this time, the weight of the inner container 50 is sufficiently large that the inner container 50 and the capacitance element 10 do not float. The second resin 40 is then cured together with the outer container 30 (step 73), thereby manufacturing the capacitor 1.

[Embodiment 3]
Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

In the third embodiment, the process of injecting the second resin 40 in the manufacturing process of the capacitor 1 according to the first embodiment is different from that in the first embodiment. FIG. 4 is a model diagram showing the manufacturing process of the capacitor 1 according to the third embodiment. In the manufacturing process of the capacitor 1 according to the third embodiment, steps 61 to 64 are the same as those in the first embodiment.

After the inner container 50 and the capacitive element 10 are bonded with the first resin, the bonded inner container 50 is placed in the outer container 30, and the inner container 50 and the outer container 30 are temporarily fixed together with clips 80 (step 81).

The second resin 40 is first poured into the outer container 30, but not into the inner container 50 (step 82). As the pouring of the second resin 40 continues, the liquid level in the outer container 30 becomes higher than the height of the upper edge of the inner container 50, and the second resin 40 enters the inner container 50 from the upper edge of the inner container 50 (step 83). At this time, since the inner container 50 and the outer container 30 are temporarily fixed by the clip 80, the inner container 50 and the capacitance element 10 do not float, regardless of the specific gravity of the inner container 50 side and the specific gravity of the second resin 40.

The second resin 40 is continued to be poured until the liquid level reaches a specified height (step 84). After that, the clip 80 is removed, and the second resin 40 is cured together with the outer container 30 (step 85), thereby manufacturing the capacitor 1.

In other embodiments, fixing the inner container 50 and the outer container 30 with clips 80 is also effective in preventing the inner container 50 and the capacitance element 10 from floating up. Therefore, the position of the capacitance element 10 in the capacitor 1 can be controlled with high precision, resulting in a capacitor with high insulation performance.

[Embodiment 4]
Other embodiments of the present invention will be described below. For ease of explanation, the same reference numerals are given to members having the same functions as those described in the above embodiment, and the description thereof will not be repeated.

In the fourth embodiment, the timing of hardening of the first resin in the manufacturing process of the capacitor 1 in the first to third embodiments is different. FIG. 5 is a model diagram showing the manufacturing process of the capacitor 1 in the fourth embodiment. In the manufacturing process of the capacitor 1 in the fourth embodiment, steps 61 to 63 are the same as those in the first embodiment.

A small amount of the first resin 20 is injected into the outer container 30, and then the inner container 50 containing the capacitance element 10 coated with the first resin 20 is placed in the outer container 30 (step 91). The first resin 20 is then cured for the outer container 30, inner container 50, and capacitance element 10, and the outer container 30, inner container 50, and capacitance element 10 are bonded together (step 92).

The second resin 40 is poured into the outer container 30 and/or the inner container 50 using any of the methods of embodiments 1 to 3 (step 93). The pouring of the second resin 40 is continued until the liquid level reaches a specified height (step 94). At this time, since the outer container 30, the inner container 50, and the capacitance element 10 are bonded together by step 92, the capacitance element 10 does not float up.

Then, the second resin 40 is cured together with the outer container 30 (step 95) to manufacture the capacitor 1.

[Modifications]
In all of the first to third embodiments, the capacitor 1 is manufactured by two-step curing, that is, curing the first resin 20 and curing the second resin 40, but the number of times of curing may be increased. Specifically, the second resin 40 may be primarily cured at step 67 in the first embodiment, at step 71 in the second embodiment, and at step 82 in the third embodiment. In this case, even if the clips 80 are not used and a light inner container 50 is used, it is possible to prevent the capacitance element 10 from floating up.

In the fourth embodiment, instead of the inner container 50, an inner bottom made of resin may be provided. In this case, the inner bottom prevents contact between the capacitive element 10 and the bottom surface of the outer container 30, and the position of the capacitive element 10 relative to the outer container 30 is determined by bonding with the first resin. Therefore, unlike the inner container 50, it is not necessary to surround five sides of the capacitive element 10, and the inner bottom may cover only one side of the bottom surface.

〔summary〕
A capacitor according to aspect 1 of the present invention comprises a capacitive element including a pair of electrodes and a dielectric located between the pair of electrodes, an outer container, a resin inner container in which the capacitive element is disposed and which is located between the capacitive element and the outer container, and a filling resin filled in the inner container and the outer container.

With the above configuration, the presence of a resin inner container between the capacitance element and the outer container ensures sufficient insulation of the capacitance element.

The capacitor according to aspect 2 of the present invention may be configured in the above aspect 1, further comprising a coating resin that covers the capacitive element and does not contain a filler.

With the above configuration, the capacitance element is covered with a coating resin, which prevents oxygen and water vapor from entering the capacitor, preventing deterioration of the capacitor's performance.

The capacitor according to aspect 3 of the present invention may be configured in the above aspect 2 such that there is a portion between the capacitance element and the inner container where only the coating resin is present.

According to the above configuration, the capacitive element and the inner container are bonded by the coating resin. This makes it possible to prevent the capacitive element from shifting or floating up due to the injection of the filling resin.

The capacitor according to aspect 4 of the present invention may be configured in any one of aspects 1 to 3 above, in which the filling resin is a resin containing a filler.

The above configuration reduces heat generation during hardening of the filling resin, which requires a large amount of resin to be hardened, and therefore does not damage the capacitive element.

The method for manufacturing a capacitor according to aspect 5 of the present invention includes the steps of forming a capacitance element using a pair of electrodes and a dielectric located between the pair of electrodes, housing the capacitance element in a resin inner container, housing the inner container in an outer container, filling the inner container and the outer container with a filling resin, and hardening the filling resin.

With the above configuration, the presence of a resin inner container between the capacitance element and the outer container ensures sufficient insulation of the capacitance element.

The method for manufacturing a capacitor according to aspect 6 of the present invention may further include, in the above aspect 5, a step of coating the capacitance element with a coating resin that does not contain a filler before the capacitance element is placed in the inner container.

With the above configuration, the capacitance element is covered with a coating resin, which prevents oxygen and water vapor from entering the capacitor, and thus prevents deterioration of the capacitor's performance.

The method for manufacturing a capacitor according to aspect 7 of the present invention may further include, in the above-mentioned aspects 5 or 6, a step of curing the coating resin after the capacitance element is housed in the inner container.

According to the above configuration, the capacitive element and the inner container are bonded by the coating resin. This makes it possible to prevent the capacitive element from shifting or floating up due to the injection of the filling resin.

[Additional Notes]
The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

REFERENCE SIGNS LIST 1, 100 Capacitor 10 Capacitive element 11 Wound body 12 Metallikon electrode 13 External terminal 20 First resin (coating resin)
30 Outer container 40 Second resin (filling resin)
50 Inner packaging

Claims (7)

A capacitor,
A capacitive element including a pair of electrodes and a dielectric material located between the pair of electrodes;
An outer container;
an inner container made of resin, the inner container having the capacitance element disposed therein and positioned between the capacitance element and the outer container;
and a filling resin filled in the inner container and the outer container. The capacitor according to claim 1, further comprising a coating resin that covers the capacitive element and does not contain a filler. The capacitor according to claim 2, in which there is a portion between the capacitance element and the inner container where only the coating resin is present. The capacitor according to any one of claims 1 to 3, wherein the filling resin is a resin containing a filler. A method for manufacturing a capacitor, comprising the steps of:
forming a capacitance element by a pair of electrodes and a dielectric material located on the pair of electrodes;
a step of housing the capacitive element in an inner container made of resin;
placing the inner container in an outer container;
filling the inner container and the outer container with a filling resin;
and curing the filled resin. The manufacturing method according to claim 5 further includes a step of coating the capacitive element with a coating resin that does not contain a filler before the capacitive element is placed in the inner container. The manufacturing method according to claim 6 further includes a step of curing the coating resin after the capacitance element is housed in the inner container.

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