JPH10106901A - Electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrolytic capacitor of an element fixing structure in which, even when a capacitor element vibrates in a metal case when the electrolytic capacitor receives a vibration, shaking of an internal terminal of the capacitor element due to the vibration is restricted to prevent disconnection of the internal terminal caused by metal fatigue. SOLUTION: An opening sealing plate, which is provided with a cylindrically protruded lower end surface and formed on a closed-end cylinder, is formed by integrating an end part of a cylinder 9 with an opening sealing plate 25 simple substance or an opening sealing plate 15, and an internal terminal of a capacitor element 2 is connected to an external terminal in the closed-end cylinder so as to restrict the shaking width between the capacitor element 2 housed in cylinder and the internal terminal 4, thereby preventing vibration of the capacitor element 2. Further, the closed-end cylinder 9 housing the capacitor element 2 is filled with element fixing agents 7A and 7B to fix the upper part of the main body of the capacitor element 2 and the internal terminal 4 in the closed-end cylinder, thereby its disconnection is surely prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic capacitor having an improved structure for fixing a capacitor element housed in a metal case.

[0002]

2. Description of the Related Art In FIG. 6, reference numeral 2 denotes a capacitor element formed by winding each of an anode foil and a cathode foil through electrolytic paper and winding a resin-made tape 10 around the periphery thereof. The electrolytic capacitor 1 is housed in a cylindrical metal case 3 having a bottom. Reference numeral 4 denotes an internal terminal (tab) of the capacitor element 2 which is electrically connected to each of the anode foil and the cathode foil and is drawn out from the end face of the capacitor element 2. 5 is a cylindrical sealing plate having an annular step on the outer periphery,
A pair of external terminals (screw terminals) 6 are fixed through.
The internal terminal 4 is joined to an external terminal 6 through which a cylindrical sealing plate 5 is inserted. Reference numeral 7 denotes an element fixing agent that fills a gap between the metal case 3 and the capacitor element 2 so that the capacitor element 2 does not vibrate in the metal case 3.

The element fixing agent 7 is filled in a state of being melted by heat in advance, such as coal tar, and is thermoplastic, which is cooled and solidified, or thermosetting, which is filled with heat and then cured by heat, such as epoxy resin. Is used. When the element fixing agent 7 filled in the metal case 3 hardens, the sealing plate 5 is fitted into the opening end of the metal case 3. A rubber 8 having a square ring shape is arranged on the annular step portion of the sealing plate 5. In this state, the opening end of the metal case 3 is swaged to fix the sealing plate 5 to the metal case 3.

[0004]

An electrolytic capacitor requires a hollow air reservoir inside to reduce the rise in internal pressure due to gasification of an electrolytic solution impregnated in a capacitor element housed in a metal case by applying a voltage. And Therefore, it is necessary to provide a gap between the metal case and the capacitor element.If the electrolytic capacitor receives vibration, the capacitor element vibrates with the swing width of the gap provided between the metal case and the capacitor element, The internal terminal (tab) of the capacitor element is disconnected. In order to prevent such disconnection of the internal terminals, in a conventional electrolytic capacitor, a gap between the inside of the metal case and the capacitor element is filled with an element fixing agent so that the capacitor element does not vibrate in the metal case.

However, in the conventional electrolytic capacitor, only the element fixing agent is filled in the bottom of the metal case, and the vicinity of the sealing plate is formed in a hollow air pocket, so that the internal terminal side of the capacitor element is sufficiently fixed. If the internal terminals of the capacitor element are vibrated, the internal terminals are liable to break due to metal fatigue, and an improvement in the element fixing structure has been desired.

According to the present invention, even if the capacitor element 2 vibrates in the metal case 3 when the electrolytic capacitor is subjected to vibration, the vibration restricts the swing of the internal terminal of the capacitor element, and the internal terminal is caused by metal fatigue. An object of the present invention is to provide an electrolytic capacitor having an element fixing structure for preventing disconnection.

[0007]

An electrolytic capacitor according to the present invention is provided with a capacitor element in which both electrode foils are wound through electrolytic paper, and is pulled out from an end face of the capacitor element.
An internal terminal electrically connected to the electrode foils of both electrodes, and a sealing plate having a wall portion surrounding the external terminals on an end surface facing the capacitor element while fixing the external terminals of both electrodes, An internal terminal pulled out from an end face of the capacitor element is connected to an external terminal fixed to a sealing plate, and a connection part thereof and a part of the capacitor element are housed in a wall of the sealing plate.
One feature. The electrolytic capacitor of the present invention surrounds the external terminal by providing a threaded portion around the external terminal of the sealing plate, and screwing the end of the cylinder into the threaded portion and screwing the end of the cylinder. One feature is that the wall is formed by the inner surface of the cylinder. One feature of the electrolytic capacitor of the present invention is that the wall surrounding the external terminal is formed by integrally molding the wall surrounding the external terminal with the sealing plate. The electrolytic capacitor of the present invention
One feature is that an element fixing agent is filled and solidified in the wall portion that accommodates a connection portion between the internal terminal and the external terminal and a part of the capacitor element in a wall portion of the sealing plate.

[0008]

FIG. 1, FIG. 2, FIG. 3, and FIG.
This will be described with reference to the drawings shown in FIG. FIG. 1 is a sectional view showing an embodiment of the electrolytic capacitor of the present invention, FIGS. 2 and 3 are sectional views showing an example of a manufacturing process of the electrolytic capacitor of the embodiment, and FIG. 4 is a sectional view showing an electrolytic capacitor of another embodiment. FIG. Further, the reference numerals used in FIGS. 1, 2, 3, and 4 showing the respective embodiments, and the same reference numerals as those in FIG. 6 indicate the same components. The metal case 3 employs an explosion-proof structure known in Japanese Utility Model Laid-Open No. 57-37236, which has an explosion-proof groove on the side surface.

In FIG. 3, reference numeral 2 denotes a capacitor element formed by winding each of an anode foil and a cathode foil via an electrolytic paper and winding a resin-made tape 10 around the periphery thereof, which is impregnated with an electrolytic solution. The electrolytic capacitor 1 is housed in a bottom cylindrical metal case 3. Reference numeral 4 denotes an internal terminal (tab) of the capacitor element 2 which is electrically connected to each of the anode foil and the cathode foil and is drawn out from the end face of the capacitor element 2. Reference numeral 15 denotes a sealing plate having a cylindrical portion protruding in the center of the end face facing the capacitor element 2, and a male screw formed on the outer peripheral surface of the cylindrical protruding portion. The sealing plate 15 has a large-diameter flange formed at the center in the thickness direction, and penetrates through a cylindrical projection from the upper end surface to the lower end surface in the state of FIG. 3 to form a pair of external terminals (screw terminals). 6 is fixed. Sealing plate
The internal terminals 4 of the capacitor element 2 are connected to a pair of external terminals 6 penetrating through the cylindrical projecting portion on the lower end surface of the capacitor element 15, and the capacitor element 2 is fixed to the sealing plate 15.

In FIG. 2, a cylinder 9 is screwed into a male screw formed on an outer peripheral surface of a cylindrical projecting portion at a lower end surface of the sealing plate 15 and the cylinder 9 is attached to a lower end surface of the sealing plate 15. A low cylinder is formed on the lower end surface of the 15. Thus, the capacitor element 2 of the sealing plate 15
A wall (the inner cylinder surface of the cylinder 9) surrounding the external terminal is formed on the end face (lower end face) facing the. The pair of external terminals 6 described with reference to FIG. 3 are fixed to the bottom surface in the cylinder.
In the state where the internal terminals 4 of the capacitor element 2 are connected, the connection portion and a part of the capacitor element (main body) 2 are accommodated in the inner cylinder surface of the cylinder 9. At this time, if the inner diameter of the cylinder 9 is formed slightly larger than the outer diameter of the capacitor element 2 and the shape of the inner cylinder of the cylinder 9 is formed so as to conform to the external shape of the capacitor element 2, There is almost no gap between the capacitor elements 2. If the shape of the inner cylinder of the cylinder 9 matches the appearance of the capacitor element 2 and there is almost no gap between the inside of the cylinder 9 and the capacitor element 2, the capacitor element 2 housed in the cylinder 9 Although the vibration occurs together with the cylinder 9, the swing width between the capacitor element 2 and the internal terminal 4 during this vibration is limited, so that disconnection of the internal terminal 4 due to metal fatigue is prevented. In this case, the capacitor element 2 is housed in the metal case 3 together with the sealing plate 15 with the sealing plate 15 side up without using the element fixing agent (7A, 7B), and the opening end of the metal case 3 is crimped. Alternatively, the sealing plate 15 may be fixed to the opening end of the metal case 3 to form an electrolytic capacitor.

As described above, if only a part of the capacitor element (main body) 2 is accommodated in the inner cylinder surface of the cylinder 9 without using the element fixing agents (7A, 7B), the inside of the cylinder 9 and the capacitor element 2
Is large, the vibration width generated between the capacitor element 2 and the internal terminal when the cylinder 9 is vibrated is hardly limited, and disconnection of the internal terminal due to metal fatigue is not prevented. Therefore, as shown in FIG. 2, the element fixing agent 7A is filled in a wall inside the bottomed cylinder formed by the cylinder 9 attached to the sealing plate 15 with the sealing plate 15 side down, and the upper part of the main body of the capacitor element 2 is formed. Is hardened while immersed in the element fixing agent 7A, and the upper part of the main body of the capacitor element 2 is firmly fixed in the bottomed cylinder. If the electrolytic capacitor is formed in this manner, even if the capacitor element 2 housed in the cylinder 9 vibrates, disconnection due to metal fatigue of the internal terminal 4 is prevented by integrally fixing the capacitor element 2 and the internal terminal during this vibration. Is done.

In order to prevent the capacitor element 2 from completely vibrating in the metal case 3, the lower part of the main body of the capacitor element 2 is also fixed to the metal case 3, as shown in FIG.
In FIG. 1, as shown in FIG. 2, the wall inside the bottomed cylinder formed by the cylinder 9 attached to the sealing plate 15 is filled with the element fixing agent 7A.
In the state described above, the capacitor element 2 is stored in the metal case 3 together with the sealing plate 15 with the sealing plate 15 side up. And
The metal case 3 is filled with the element fixing agent 7B and cured while the lower part of the capacitor element body is immersed in the element fixing agent 7B, and the lower part of the capacitor element body is firmly fixed to the bottom side of the metal case 3. At the same time, the sealing plate 15 is fixed to the opening end of the metal case 3 by caulking the opening end of the metal case 3.
The element fixing agents 7A and 7B may be the same as the element fixing agent 7 described with reference to FIG.
Others may be used at 7B. Element fixing agents 7A, 7
When B is a thermoplastic material such as atactic polypropylene, it is heated and melted and filled by heat treatment before filling, and cooled and solidified after filling. In the case where the element fixing agents 7A and 7B are thermosetting materials such as epoxy resin and silicone rubber, the element fixing agents 7 in a molten state at room temperature are used.
Is heated and solidified by heat treatment after filling.

FIGS. 1, 2, and 3 show that a threaded portion is provided around an external terminal fixed to a sealing plate, and an end of a tube is screwed into the threaded portion to screw the end of the tube. A sealing plate having a wall portion surrounding the external terminal formed by the inner surface of the cylinder by projecting the center portion of the lower end surface into a cylindrical shape, and forming a male screw on the outer peripheral surface of the cylindrical projecting portion of the lower end surface.
The description has been made by adopting the cylinder 9 having a female screw formed at the end of the inner cylinder and screwing with the sealing plate 15. However, the configuration in which the sealing plate and the cylinder are screwed is not limited to the above embodiment.

For example, as shown in FIG. 5, the center of the end face (lower end face) facing the capacitor element 2 is left in a cylindrical shape.
A sealing plate 35 having an annular groove formed along the peripheral surface of the cylinder is used. Then, a female screw is formed on the outer peripheral surface in the annular groove on the lower end surface of the sealing plate 35. Then, using a cylinder 19 having an external thread formed on the outer peripheral surface of the end, the external thread at the end of the cylinder 19 is screwed with the female screw of the annular groove of the sealing plate 35 to thereby form the lower end surface of the sealing plate 15. A low cylinder is formed. In this way, the end face (lower end face) of the sealing plate 15 facing the capacitor element 2 has a wall (cylindrical) surrounding the external terminal 36.
19 inner cylindrical surfaces) are formed. A tube is attached to the lower end face of this sealing plate 35.
The shape of FIG. 5 in which 19 is screwed is almost the same as the shape of FIG. 1 in which the cylinder 19 is screwed to the sealing plate 15.

In FIG. 5, a pair of external terminals 36 fixed to the sealing plate 35 are arranged on the bottom surface in the cylinder 19, and each internal terminal 4 of the capacitor element 2 is connected to each external terminal 36 in the cylinder 19. In this state, the connection portion and a part of the capacitor element (main body) 2 are accommodated in the inner cylinder surface of the cylinder 19. As described above, if the inner diameter of the cylinder 19 is formed slightly larger than the outer diameter of the capacitor element 2 and the shape of the inner cylinder of the cylinder 19 is formed so as to match the external shape of the capacitor element 2,
There is almost no gap between the inside of the cylinder 19 and the capacitor element 2. If the shape of the inner cylinder of the cylinder 19 matches the appearance of the capacitor element 2 and there is almost no gap between the inside of the cylinder 19 and the capacitor element 2, the capacitor element 2 housed in the cylinder 19 Although the vibration occurs together with the cylinder 9, the swing width between the capacitor element 2 and the internal terminal 4 during this vibration is limited, so that disconnection of the internal terminal 4 due to metal fatigue is prevented.

In this case, the capacitor element 2 is housed in the metal case 3 together with the sealing plate 35 with the sealing plate 15 side up without using the element fixing agent (7A, 7B). It is also possible to fix the sealing plate 35 to the open end of the metal case 3 to form an electrolytic capacitor as described with reference to FIG.

As described above, if only a part of the capacitor element (main body) 2 is accommodated in the inner cylinder surface of the cylinder 19 without using the element fixing agents (7A, 7B), the inside of the cylinder 19 and the capacitor element 2
Is large, the vibration width generated between the capacitor element 2 and the internal terminal when the cylinder 19 is vibrated is hardly limited, and disconnection of the internal terminal due to metal fatigue cannot be prevented. In this case, the wall inside the bottomed cylinder formed by the cylinder 19 attached to the sealing plate 35 is filled with the element fixing agent 7A, and cured while the upper part of the main body of the capacitor element 2 is immersed in the element fixing agent 7A. Then, the upper part of the main body of the capacitor element 2 is firmly fixed in the bottomed cylinder to form an electrolytic capacitor. In this electrolytic capacitor, even if the capacitor element 2 housed in the cylinder 19 vibrates, the capacitor element 2 and the internal terminal are integrally fixed during the vibration, so that the internal terminal 4 does not break due to metal fatigue. This is as described in FIG. In order to prevent the capacitor element 2 from completely vibrating in the metal case 3, the lower part of the main body of the capacitor element 2 may be fixed to the metal case 3 as described with reference to FIG.
The method of fixing the lower part of the main body of the capacitor element 2 is the same as that in FIG. 1, and the description is omitted here.

Next, another embodiment of the present invention will be described with reference to FIG. The element fixing agent used here is the same as that used at the time of manufacturing the electrolytic capacitor of FIG. The capacitor of FIG. 4 uses a sealing plate 25 in which the sealing plate 15 and the cylinder 9 constituting the electrolytic capacitor of FIG. 1 are integrally formed by molding. The sealing plate 25 is formed in a bottomed cylinder whose lower surface protrudes in a cylindrical shape, and has an open end. The cylindrical portion 11 projects from the lower surface of the sealing plate 25. Inside the cylindrical portion 11, a pair of external terminals 16 are provided.
In the pre-process of fixing the sealing plate 25 to the metal case 3, each internal terminal 4 of the capacitor element 2 is connected to each external terminal in the cylindrical portion 11. Then, with the sealing plate 25 side down, the bottomed cylinder is filled with the element fixing agent 7A, and the upper part of the main body of the capacitor element is cured while being immersed in the element fixing agent 7A. Firmly. Next, the capacitor element 2 is housed in the metal case 3 together with the sealing plate 25 with the sealing plate 25 side facing upward. Then, the metal case 3 is filled with the element fixing agent 7B, and the lower part of the main body of the capacitor element is cured while immersed in the element fixing agent 7B. At the same time, the sealing plate 25 is fixed to the opening end of the metal case 3 by caulking the opening end of the metal case 3.

According to the present invention, the bottom plate is formed in a bottomed cylinder projecting in a cylindrical shape, and the end plate of the bottomed tube is opened with the sealing plate alone, or the end of the tube is incorporated into the sealing plate. It is formed by. Then, if the internal terminal of the capacitor element is joined to the external terminal in the bottomed cylinder and there is almost no gap between the cylinder and the capacitor element, even if vibration occurs in the electrolytic capacitor, it is accommodated in the cylinder. The swing width between the capacitor element and the internal terminal is limited, and disconnection of the internal terminal due to metal fatigue is prevented.

According to the present invention, when the gap between the cylinder and the capacitor element is large, the bottomed cylinder for accommodating the capacitor element with the internal terminal of the capacitor element joined to the external terminal in the bottomed cylinder. A structure in which an element fixing agent is filled therein and the upper part of the main body of the capacitor element and the internal terminals are fixed in the bottomed cylinder is also employed to surely prevent disconnection of the internal terminals.

Further, in order to surely prevent the vibration of the capacitor element, the above-mentioned one in which the upper part of the main body of the capacitor element and the internal terminals are fixed with an element fixing agent in a bottomed cylinder protruding toward the sealing plate side is made of metal. It is housed in a case, and the element fixing agent is filled in the metal case to fix the lower part of the capacitor element body, and at the same time, the opening end of the metal case is swaged to fix the sealing plate to the opening end of the metal case. The element may be completely fixed to the metal case at the top and bottom of the main body. still,
The metal case has an explosion-proof groove on the side.
It is preferable to adopt an explosion-proof structure known in Japanese Patent Publication No. 236, so that even if the element fixing agent is hardened on the upper and lower surfaces in the metal case, the explosion-proof structure is not affected.

[0022]

The electrolytic capacitor of the present invention is formed in a bottomed cylinder whose lower surface protrudes in a cylindrical shape, and a sealing plate having an open end at the end of the bottomed cylinder is used as a sealing plate alone or as a sealing plate. The internal terminal of the capacitor element is joined to the external terminal in the bottomed cylinder, and even if the electrolytic capacitor vibrates, the gap between the capacitor element housed in the cylinder and the internal terminal is formed. The swing width is limited, and vibration of the capacitor element housed in the metal case can be reliably prevented. In addition, a configuration is used in which the element fixing agent is filled in the bottomed cylinder that houses the capacitor element, and the upper part of the main body of the capacitor element and the internal terminal are fixed in the bottomed cylinder, thereby reliably preventing disconnection of the internal terminal. . Therefore, when combined with a conventional fixing structure in which the metal case is filled with an element fixing agent to fix the lower part of the main body of the capacitor element, it is practical that the vibration of the capacitor element can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of the electrolytic capacitor of the present invention.

FIG. 2 is a sectional view showing an example of a manufacturing process of the electrolytic capacitor of FIG.

FIG. 3 is a sectional view showing an example of a manufacturing process of the electrolytic capacitor of FIG.

FIG. 4 is a sectional view showing a third embodiment of the electrolytic capacitor of the present invention.

FIG. 5 is a sectional view showing a second embodiment of the electrolytic capacitor of the present invention.

FIG. 6 is a sectional view of a conventional electrolytic capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrolytic capacitor 2 Capacitor element 3 Metal case 4 Inner terminal 5 Sealing plate 6 External terminal 7 Element fixing agent 7A Element fixing agent 7B Element fixing agent 8 Rubber 9 Tube 10 Winding tape 11 Tube portion 15 Sealing plate 16 External terminal 19 Tube 25 Sealing plate 26 Groove 35 Sealing plate 36 External terminal

Claims (4)

[Claims] 1. A capacitor element in which electrode foils of both electrodes are wound through electrolytic paper, an internal terminal pulled out from an end face of the capacitor element and electrically connected to the electrode foils of both electrodes, and an external terminal of both electrodes. A sealing plate provided with a wall surrounding the external terminal on an end face facing the capacitor element while fixing the terminal; connecting an internal terminal drawn out from the capacitor element end face to an external terminal fixed to the sealing plate; An electrolytic capacitor, wherein a connection part thereof and a part of the capacitor element are accommodated in a wall of the sealing plate. 2. A wall portion surrounding the external terminal is provided with a threaded portion around the external terminal of the sealing plate, and an end of the cylinder is screwed into the threaded portion to screw the end of the cylinder. 2. The electrolytic capacitor according to claim 1, wherein said electrolytic capacitor is formed on the inner surface of said cylinder. 3. The electrolytic capacitor according to claim 1, wherein the wall surrounding the external terminal is formed by integrally molding the wall surrounding the external terminal with the sealing plate. 4. An element fixing agent is filled and solidified in a wall surrounding the external terminal in which a connection portion between the internal terminal and the external terminal and a part of the capacitor element are accommodated in a wall of the sealing plate. The electrolytic capacitor according to claim 1, wherein