JP2013229390A - Capacitor and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the adhesion strength between a case and a sealing resin layer thereby improving the reliability of a capacitor.SOLUTION: A capacitor includes: a capacitor element (12); a case (a metal case 4) having an engagement wall part (10) narrowing an opening area from a housing part (6) where the capacitor element is housed toward an opening (8); and a sealing resin layer (38) filling the housing part of the case, into which the capacitor element is inserted, and sealing the capacitor element while covering a part of or the entire capacitor element. The sealing resin layer is engaged with the engagement wall part (10) in the case.

Description

The present invention relates to a capacitor sealed in a case by filling a sealing resin, for example, a capacitor such as a dry metallized film capacitor and a method for manufacturing the same.

  In the field of power electronics, for example, a metalized film capacitor is used for a smoothing circuit of a high-output power source. In such applications, a metallized film capacitor having a high withstand voltage and a large capacity is required. In such a metallized film capacitor, a metallized film obtained by evaporating aluminum or the like on a polypropylene film is used as a capacitor element, and impregnated with insulating oil.

  When a flammable insulating oil is used as the insulating oil impregnated in the capacitor element, there is a disadvantage that the capacitor element easily burns. In contrast to such a wet type, in a dry-type metalized film capacitor, the capacitor element is fixed together with a terminal plate connected to the capacitor element in the case with a sealing resin. Since dry type does not use insulating oil, it does not have the disadvantages of wet type.

With respect to resin sealing of capacitors, it is known that a case containing a capacitor element is filled with sealing resin, and a terminal support plate is installed in the sealing resin (for example, Patent Document 1). It is known that an electrode lead-out portion is formed by metallicon on an element end face of a capacitor element using a dielectric film on which a metal vapor-deposited electrode is formed, and the electrode lead-out portion and the electrode terminal are connected by a lead wire (for example, Patent Documents 2, 3, 4).

Japanese Utility Model Publication No. 56-16926 Japanese Utility Model Publication No. 7-29829 JP 2008-270329 A JP 2009-277828 A

  By the way, in a capacitor in which a capacitor element is put in a metal case and sealed in a metal case with a sealing resin, when the capacitor element expands due to an abnormal surge voltage or a gas is generated, it protrudes from the metal case to the sealing resin or the capacitor element Stress may be applied in the direction. When this stress exceeds the adhesion between the metal case and the sealing resin, there is a problem that the sealing resin is detached from the metal case and the capacitor element protrudes from the metal case together with the sealing resin. Even if it does not protrude, there is a problem that expansion of the capacitor element in the metal case deforms the metal case.

  Such a problem is that not only the metal case but also the case and the sealing resin are separate members, the sealing resin and the capacitor element protrude from the case when the adhesion between the case and the sealing resin is low. There are challenges.

In view of the above problems, an object of the present invention is to increase the adhesion strength between the case and the sealing resin layer and to increase the reliability of the capacitor.

  In order to achieve the above object, a capacitor according to the present invention includes a capacitor element, a case having a locking wall portion whose opening area is narrowed from the storage portion in which the capacitor element is stored toward the opening, and the capacitor element includes: A sealing resin layer that fills the housing portion of the inserted case, covers a part or all of the capacitor element, and seals the inside of the housing portion, and the sealing resin layer is disposed on the locking wall. The part is locked in the case.

  The capacitor further includes a terminal plate to which a terminal connected to the capacitor element is attached and is provided with a step portion covered with the sealing resin layer, and the terminal plate includes the step portion in the case within the case. It may be buried and fixed in the stop resin layer.

  In the above capacitor, the capacitor element may be a metallized film capacitor element.

  The capacitor may further include a resin penetrating portion through which the sealing resin layer is inserted into the stepped portion of the terminal board.

In order to achieve the above object, a method of manufacturing a capacitor according to the present invention includes a step of forming a capacitor element, and a locking wall portion whose opening area is narrowed from the storage portion in which the capacitor element is stored toward the opening portion. A step of forming a case, and the case in which the capacitor element is inserted is filled with a sealing resin and cured, and a part or all of the capacitor element is covered with a sealing resin layer, Sealing the capacitor element.

  According to the present invention, the following effects can be obtained.

  (1) The sealing resin layer that fills the case and covers the capacitor element is locked in the case and held in the case by the locking wall part whose opening area is narrowed from the storage part toward the opening. can do.

  (2) The holding power of the sealing resin layer in the case is enhanced, and inconveniences such as popping out can be avoided.

  (3) The sealing strength by the sealing resin layer can be increased and the reliability of the capacitor can be increased.

Other objects, features, and advantages of the present invention will become clearer with reference to the accompanying drawings and each embodiment.

It is a longitudinal section showing a capacitor concerning a 1st embodiment. It is a top view which shows the capacitor | condenser seen from the terminal surface part. It is sectional drawing which expands and shows the III part of the capacitor | condenser shown in FIG. It is sectional drawing which expands and shows the capacitor | condenser part which concerns on 2nd Embodiment.

[First Embodiment]

  FIG. 1 shows a longitudinal section of the capacitor according to the first embodiment. FIG. 2 shows a terminal surface of the capacitor. FIG. 3 shows an enlarged view of the portion III in FIG.

  This capacitor 2 is, for example, a metallized film capacitor. A metal case 4 is used for the capacitor 2. This metal case 4 is an example of a case, for example, an aluminum case. The metal case 4 includes a storage portion 6, an opening portion 8, and a locking wall portion 10. The storage portion 6 is a container portion that stores the capacitor element 12. The capacitor element 12 as an example is cylindrical. The storage portion 6 that stores the capacitor element 12 is a cylindrical body that can store the capacitor element 12 and includes a bottom surface portion 14.

  The opening 8 is, for example, a circular hole through which the capacitor element 12 can be inserted. The locking wall portion 10 is a tapered cylindrical portion whose opening area is narrowed from the storage portion 6 toward the opening portion 8. The metal case 4 is formed by integrally molding an aluminum plate, and the locking wall portion 10 is formed by forming an inclined wall surface that is inclined from the storage portion 6 toward the opening portion 8.

  A boss portion 16 is formed at the center of the outer surface of the bottom surface portion 14 of the metal case 4, and a screw portion 18 is formed around the boss portion 16. The screw portion 18 is used when the capacitor 2 is fixed to a mounting member such as a circuit board or a chassis. In addition, you may form the screw part 18 inside the boss | hub part 16 formed in the outer surface center of the bottom face part 14 of the metal case 4. FIG.

  A terminal plate 20 is installed on the opening 8 side of the metal case 4. The terminal board 20 is formed of an insulating board such as an insulating synthetic resin. Terminals 22-1 and 22-2 are fixed to the terminal plate 20 by insert molding. Each of the terminals 22-1 and 22-2 penetrates into and out of the terminal board 20. A step 24 is formed at the longest edge of the terminal board 20.

  The terminal 22-1 and the element end face 26-1 of the capacitor element 12 are connected by solder using a lead wire 31. A terminal lead wire 32 drawn from the hollow portion 30 of the capacitor element 12 is connected to the terminal 22-2. The terminal lead wire 32 is connected to an electrode portion formed on the element end face 26-2 of the capacitor element 12 by solder.

  The capacitor element 12 is an element body formed by winding a metallized film. In the metallized film, a dielectric film is used as a base material. This dielectric film is metallized by depositing an electrode metal such as aluminum on at least one surface. For the dielectric film, for example, a synthetic resin film such as polyethylene terephthalate or polypropylene is used.

  The capacitor element 12 includes element end faces 26-1 and 26-2. In this embodiment, a positive electrode portion is formed on the element end surface 26-1, and a negative electrode portion is formed on the element end surface 26-2. A positive electrode body of the capacitor element 12 is exposed on the element end face 26-1, and a negative electrode body is exposed on the element end face 26-2. Thus, each element end surface 26-1 and 26-2 is comprised by the different electrode. For the capacitor element (element body) 12, the width of the metallized film on the positive electrode body side and the width of the metallized film on the negative electrode body side may be different. On the other hand, by making the dielectric film forming the metallized film the same width and making the metal vapor deposition width (range) different from the dielectric film, for example, the positive electrode body, the element end face 26- You may comprise so that a negative electrode body may be exposed to 2 side. That is, it is configured so that different electrode bodies are not exposed on one element end face 26-1 or element end face 26-2.

  Thus, electrode metal is vapor-deposited on the element end faces 26-1 and 26-2 made of the positive electrode body or the negative electrode body by metallicon, the positive electrode side electrode portion on the element end face 26-1, and the negative electrode side on the element end face 26-2. An electrode part is formed. The electrode metal constituting the positive electrode portion and the negative electrode portion may be the same as or different from the electrode metal deposited on the dielectric film of the metallized film. In this case, the element end faces 26-1 and 26-2 may be made of a solderable metal for ease of connection such as soldering. For example, a metal such as zinc or a tin alloy may be used as the solderable metal. In addition, for example, an alloy of aluminum and zinc, an aluminum and tin alloy, or a zinc and tin alloy may be used as a solderable metal.

  For example, a polyethylene film 36 is installed as an insulating means between the element end face 26-1 and the terminal 22-2. The polyethylene film 36 ensures insulation between the element end face 26-1 side and the terminal 22-2.

  In this embodiment, the terminal plate 20 is installed on the element end face 26-1 side of the capacitor element 12. The outer surface of the terminal plate 20 is matched with the edge surface of the opening 8 of the metal case 4. The metal case 4 is filled with a sealing resin, and a sealing resin layer 38 is formed. As the sealing resin, a highly insulating resin is used, and the highly insulating sealing resin layer 38 is formed. The sealing resin layer 38 covers the outer peripheral surface of the capacitor element 12 and the element end surfaces 26-1 and 26-2 and fills the hollow portion 30. Further, the sealing resin layer 38 is in close contact with the inner wall surface of the metal case 4.

  In such a configuration, as shown in FIG. 3, the locking wall portion 10 of the metal case 4 is narrowed from the storage portion 6 toward the opening portion 8, so that the sealing resin layer 38 is firmly formed in the metal case 4. Is held in. Since the metal case 4 is constricted on the opening 8 side, the mechanical strength is increased, and even if a stress is applied to the sealing resin layer 38 in the central axis direction of the capacitor 2, the metal case 4 faces the stress. Thus, the sealing resin layer 38 can be held in the metal case 4.

  The sealing resin layer 38 is interposed between the periphery of the terminal plate 20 and the inner wall of the metal case 4, and, as shown in FIGS. 2 and 3, wraps around the step portion 24 of the terminal plate 20 and cures. Therefore, the holding strength of the terminal board 20 to the sealing resin layer 38 is increased.

<Capacitor manufacturing method>

  (1) Formation process of metal case 4, capacitor element 12, and terminal plate 20

  In this forming step, each of the metal case 4, the capacitor element 12, and the terminal plate 20 is formed individually.

  A locking wall portion 10 is formed between the opening 8 of the metal case 4 and the storage portion 6.

  (2) Connection process of the capacitor element 12 and the terminal board 20

  Before housing the capacitor element 12 in the metal case 4, the capacitor element 12 and the terminals 22-1 and 22-2 of the terminal plate 20 are electrically connected individually. By this connection, the capacitor element 12 and the terminal plate 20 are integrated.

  The capacitor element 12 is accommodated in the metal case 4, and the terminal plate 20 is installed on the element end face 26-1 side of the capacitor element 12 in the metal case 4.

  (3) Resin sealing process

  The metal case 4 is filled with a sealing resin, and the capacitor element 12 and the terminal plate 20 are fixed in the metal case 4 by curing the sealing resin layer 38.

<Effect of the first embodiment>

  (1) The adhesion between the metal case 4 and the sealing resin layer 38 can be maintained and promoted. Even when the capacitor element 12 reaches a rare state where it is ignited by application of an abnormal surge voltage or the like, it is possible to avoid a situation in which the sealing resin layer 38 enclosing the capacitor element 12 protrudes from the metal case 4. it can.

  (2) The locking wall portion 10 is a bent portion obtained by bending the open end of the metal case 4 toward the center of the case, and can be formed by such a bent portion. Thereby, the inconvenience that the capacitor element 12 and the sealing resin layer 38 pop out can be prevented.

  (3) Even when some abnormality occurs in the capacitor element 12 and the pressure in the external direction of the metal case 4 is applied to the capacitor element 12 or the sealing resin layer 38, the external direction of the capacitor element 12 or the sealing resin layer 38 It is possible to hold down the movement and maintain the sealed state.

  (4) Since the sealing resin layer 38 is filled in the gap formed between the metal case 4 and the terminal plate 20, the terminal plate 20 is sandwiched between the sealing resin layers 38, and the sealing resin layer The adhesion between the terminal plate 20 and the terminal board 20 can be improved. Thereby, the adhesiveness of the metal case 4 and the sealing resin layer 38 is improved.

[Second Embodiment]

  (1) As shown in FIG. 4A, a through hole 42 may be formed in the stepped portion 24 of the terminal plate 20 along the thick portion 40. The through hole 42 is an example of a resin through portion. If such a through hole 42 is formed, the sealing resin layer 38 is also formed in the through hole 42. The sealing resin layer 38 in the through hole 42 is integrated with other portions of the sealing resin layer 38, and the fixing strength in the sealing resin layer 38 of the terminal board 20 can be increased.

  A groove may be formed between the inner wall of the metal case 4 instead of the through hole 42.

  (2) In the above embodiment, the locking wall portion 10 is formed of a conical surface or an inclined surface. However, as shown in FIG. 4B, the locking wall portion 10 is a curved protrusion 44 protruding in the central axis direction of the metal case 4. It may be formed. Also by such a curved protrusion 44, the sealing resin layer 38 can be held in the metal case 4, and the holding strength can be enhanced.

[Other Embodiments]

  (1) In the above embodiment, the metalized film capacitor is exemplified as the capacitor. However, the present invention can be applied to a capacitor such as an electrolytic capacitor, and is not limited to the above embodiment.

  (2) In the above embodiment, the capacitor element 12 is covered with the sealing resin layer 38, but the form of the covering may be a part or the whole.

  (3) In the above embodiment, the metal case 4 is exemplified, but a resin case may be used instead of the metal case 4.

  (4) In the above embodiment, it is exemplified that the locking wall portion 10 is formed in advance on the metal case 4 before the capacitor element 12 and the terminal plate 20 are stored. It may be changed. Even if the capacitor element 12 and the terminal plate 20 are stored in the metal case 4 in which the locking wall portion 10 is not formed, the opening edge portion of the metal case 4 is bent to form the locking wall portion 10 in the metal case 4. Good. If it does in this way, the folding space | interval of the locking wall part 10 and the freedom degree of a bending process will be raised. That is, the interval between the locking wall portions 10 can be reduced with respect to the length of the terminal plate 20, the locking wall portion 10 can be superimposed on the upper surface of the terminal plate 20, and the holding strength of the sealing resin layer 38 is increased. be able to. In addition, the opening diameter of the bent metal case 4 can be made smaller than the length of the terminal plate 20, which contributes to miniaturization of the capacitor.

As described above, the most preferable embodiment of the present invention has been described. The present invention is not limited to the above description. Various modifications and changes can be made by those skilled in the art based on the gist of the invention described in the claims or disclosed in the embodiments for carrying out the invention. It goes without saying that such modifications and changes are included in the scope of the present invention.

The capacitor of the present invention and its manufacturing method can firmly fix the capacitor element together with the sealing resin using the sealing resin to the case, avoid inconveniences such as popping out of the sealing resin and the capacitor element, and improve the reliability of the capacitor. Can be increased.

DESCRIPTION OF SYMBOLS 2 Capacitor 4 Metal case 6 Storage part 8 Opening part 10 Locking wall part 12 Capacitor element 14 Bottom face part 16 Boss part 18 Screw part 20 Terminal board 22-1 and 22-2 Terminal 24 Step part 26-1 and 26-2 element End face 30 Hollow part 32 Terminal lead 36 Polyethylene film 38 Sealing resin layer 40 Thick part 42 Through hole 44 Curved protrusion

Claims (4)

A capacitor element;
A case having a locking wall portion whose opening area is narrowed from the storage portion in which the capacitor element is stored toward the opening;
A sealing resin layer that fills the storage portion of the case in which the capacitor element is inserted, covers a part or all of the capacitor element, and seals the storage portion in the storage portion;
A capacitor in which the sealing resin layer is locked in the case by the locking wall portion. Furthermore, a terminal connected to the capacitor element is attached, and a terminal plate comprising a step portion covered with the sealing resin layer,
The terminal plate is fixed by burying the stepped portion in the sealing resin layer in the case,
The capacitor according to claim 1. Furthermore, a resin penetration part that allows the sealing resin layer to be inserted into the stepped part of the terminal board is provided.
The capacitor according to claim 2. Forming a capacitor element;
Forming a case having a locking wall portion with an opening area narrowed from the storage portion in which the capacitor element is stored toward the opening;
Filling the case in which the capacitor element is inserted with a sealing resin, curing, covering part or all of the capacitor element with a sealing resin layer, and sealing the capacitor element in the case When,
A method of manufacturing a capacitor including:

Images