JPH1116788A - Electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrolytic capacitor, which prevents the generation of a short circuit between the anode foil and the cathode foil of a capacitor element especially on the bottom-part side of the case, when an abnormal stress such as an overvoltage or the like is generated and which can prevent the generation of other dangers effectively. SOLUTION: A capacitor element 10 is constituted in such a way that tab terminals 20, 22 are attached to electrode foils in which an anode foil 12 and a cathode foil 14 are overlapped properly via sheets of separator paper 16, 18 so as to be wound. The tab terminals which protrude from the capacitor element 10 are coupled and fixed respectively to external terminals derived to the outside via a sealing plate. In this case, on the upper-part side of the capacitor element 10 from which the electrode tab terminals 20, 22 are derived, the level position of the anode foil 12 and that of the cathode foil 14 are set to be identical, and, on the bottom-part side of the capacitor element 10, the length in the width direction of the anode foil 12 is set to be comparatively longer than that of the cathode foil 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an electrolytic capacitor, and more particularly to an electrolytic capacitor configured to effectively prevent a short circuit and other dangers generated between an anode foil and a cathode foil in a capacitor element. Things.

[0002]

2. Description of the Related Art In general, an electrolytic capacitor comprises a capacitor element impregnated with an electrolytic solution, an outer case for containing the same, and a sealing plate for sealing the outer case. In this case, for the capacitor element, the anode foil and the cathode foil made of aluminum foil are alternately overlapped with each other via the separator paper impregnated with the electrolyte, and the internal electrode tabs and the like are derived from each anode foil and the cathode foil. And formed by winding them.

[0003] An electrolytic capacitor can be assembled by connecting internal electrode tabs and the like derived from the capacitor element to rivets fixed to a sealing plate, and storing the capacitor element and the sealing plate in an outer case. .

However, in this type of electrolytic capacitor, the operating voltage and the like are limited by its temperature characteristics and frequency characteristics. For example, when an abnormal stress such as overvoltage occurs in a large electrolytic capacitor, the leakage current is reduced. As a result, the anode foil and the cathode foil are short-circuited, and a large current flows in the short-circuited portion, generating a spark (spark) and melting the aluminum foil. Also, in this case, while the aluminum foil is gasified and burns, the moving energy of the capacitor element is increased, and the capacitor element vigorously collides with the bottom of the outer case,
Alternatively, there is a danger of crashing into the sealing plate on the opening side of the outer case and destroying it, and burning out to the outside.

In some cases, a plurality of large electrolytic capacitors are connected and used. In this case, when a short circuit as described above occurs in one electrolytic capacitor, another electrolytic capacitor connected and arranged adjacent to the electrolytic capacitor may be used. An overcurrent flows or an overvoltage is applied to the capacitor, causing a short circuit in a chain, and the risk described above is increased.

In order to avoid such a danger of the electrolytic capacitor, various improvement measures have been proposed.

For example, as a means for preventing a short circuit between an anode foil and a cathode foil, an electrolytic capacitor in which the width of the anode foil is set to be larger than the width of the cathode foil and each of which is wound via a separator paper. Has been proposed.
No. 2-37247). That is, in the electrolytic capacitor configured in this manner, even if the burr projecting in the width direction of the anode foil breaks through the separator paper, the short width of the cathode foil prevents the occurrence of short circuit without touching the cathode foil because the width of the cathode foil is narrow. Is what you can do.

As means for preventing the outer case from being ruptured due to gasification of aluminum foil or the like, the winding portion of the core portion of the capacitor element having a space diameter of from φ1 to φ2 has an empty winding portion excluding the anode foil. The electrolytic capacitor is configured to absorb the buckling force toward the space of the core portion of the electrode foil generated near the core portion of the capacitor element due to the gas pressure, thereby preventing the anode foil from being folded. Has been proposed (JP-A-4-361517). That is, in the electrolytic capacitor configured as described above, the same short circuit as described above can be prevented by preventing the anode foil from being folded.

[0009]

However, in the conventional electrolytic capacitor, in the case of a relatively large electrolytic capacitor, the width of the anode foil is simply set to be wider than the width of the cathode foil, and each is wound via a separator paper. With just such a configuration, when unexpected abnormal stress occurs and a spark occurs due to a short circuit between the anode foil and the cathode foil on the bottom side of the outer case, the capacitor element receives large moving energy. The danger of crashing into the sealing plate on the opening side of the outer case, breaking it and jumping out cannot be eliminated.

The inventor of the present invention has conducted intensive studies and studies. As a result, when abnormal stress such as overvoltage occurs on the electrolytic capacitor, the leakage current is concentrated on the end face of the anode foil. On the upper terminal side of the capacitor element from which the terminal is led out, the level positions of the anode foil and the cathode foil are configured to be the same, and on the closed side at the bottom of the electrolytic capacitor, the width of the anode foil in the width direction is larger than that of the cathode foil. By making it relatively long, the resistance of the end face of the anode foil on the bottom side of the outer case of the capacitor element is increased, the leakage current is prevented, and it is difficult to short-circuit with the cathode foil. The safety of this type of electrolytic capacitor is improved by configuring the outer case on the opening side so that a short circuit is more likely to occur than on the bottom side. Have found that it is possible to improve on.

Accordingly, an object of the present invention is to prevent the occurrence of a short circuit between the anode foil and the cathode foil of the capacitor element, especially on the bottom side of the outer case, and to prevent other dangers when abnormal stress such as overvoltage occurs. An object of the present invention is to provide an electrolytic capacitor capable of effectively preventing occurrence of the occurrence.

[0012]

In order to achieve the above-mentioned object, an electrolytic capacitor according to the present invention comprises a tab terminal formed on an electrode foil formed by laminating an anode foil and a cathode foil through a separator paper. A capacitor element is formed by attaching and winding this, and the tab terminals protruding from the capacitor element are coupled and fixed to external terminals led out through a sealing plate. On the upper side of the capacitor element from which the two electrode tab terminals are led out, the level positions of the anode foil and the cathode foil are set to be the same, and on the bottom side of the capacitor element, the width of the anode foil in the width direction is larger than that of the cathode foil. It is characterized in that it is configured to be set relatively long.

[0013]

Next, embodiments of the electrolytic capacitor according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic structural view showing an embodiment of a main structure of an electrolytic capacitor according to the present invention. That is, in FIG. 1, reference numeral 10 denotes a capacitor element, and the capacitor element 10 is formed by separating an anode foil 12 and a cathode foil 14 made of aluminum foil, respectively, into separator papers 16 and 18 each impregnated with an electrolytic solution. , And these are superposed and wound. Reference numerals 20 and 22 denote anode foil 12 and cathode foil 1, respectively.
4 shows an electrode tab terminal derived from FIG.

However, the capacitor element 10 of this embodiment
In the above, the anode foil 12 and the cathode foil 14 are set at the same level on the upper side of the capacitor element 10 from which the two electrode tab terminals 20 and 22 are led out, and the anode foil 12 is positioned on the bottom side of the capacitor element 10. Is set to be longer by a predetermined width Δw than the width in the width direction of the cathode foil 14 (see FIG. 2).

The capacitor element 10 constructed as described above
Is housed in an outer case, sealed with a sealing plate, and a rivet portion formed at the end of an external terminal that is appropriately penetrated through the sealing plate is electrically connected to each of the electrode tab terminals. By doing so, it can be commercialized as an electrolytic capacitor.

As described above, the electrolytic capacitor having the above-described structure increases the resistance of the end face of the anode foil of the capacitor element on the bottom sealed side of the outer case when abnormal stress such as overvoltage occurs, thereby preventing leakage current. The short circuit between the anode foil and the cathode foil of the capacitor element on the opening side of the outer case can easily occur even in the event of an unexpected situation. can do. Therefore, when the spark due to the short-circuit occurs, the capacitor element that has received a large amount of moving energy can collide toward the bottom side of the outer case, thereby reliably preventing the risk of the capacitor element jumping out. Can be.

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the spirit of the present invention. .

[0019]

As described above, according to the electrolytic capacitor of the present invention, the tab terminals are attached to the respective electrode foils formed by laminating the anode foil and the cathode foil via a separator paper. To form a capacitor element by winding, the tab terminal protruding from the capacitor element, the electrolytic capacitor is fixed to the external terminal respectively led to the outside through the sealing plate,
On the upper side of the capacitor element from which the two electrode tab terminals are led out, the level positions of the anode foil and the cathode foil are set to be the same, and on the bottom side of the capacitor element, the width of the anode foil in the width direction is larger than that of the cathode foil. By setting it to be relatively long, when abnormal stress such as overvoltage occurs, the resistance of the end face of the anode foil of the capacitor element on the sealed side at the bottom of the outer case increases, preventing leakage current and shorting with the cathode foil. It is possible to make it difficult to
Even in the case where an unexpected situation occurs, a state in which a short circuit easily occurs between the anode foil and the cathode foil of the capacitor element on the opening side of the outer case can be achieved.

As a result, when a spark occurs due to short-circuiting of the capacitor element on the opening side of the outer case, the capacitor element that has received a large amount of moving energy is:
The collision can be made to collide with the bottom side of the outer case, whereby the risk of the capacitor element jumping out can be reliably prevented. Therefore, the safety of this type of electrolytic capacitor can be further enhanced.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a main part structure of an electrolytic capacitor according to the present invention.

FIG. 2 is an explanatory view showing a dimensional configuration of an anode foil and a cathode foil of the electrolytic capacitor shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Capacitor element 12 Anode foil 14 Cathode foil 16, 18 Separator paper 20, 22 Electrode tab terminal

Claims (1)

[Claims] 1. A capacitor element is formed by attaching a tab terminal to an electrode foil formed by laminating an anode foil and a cathode foil through a separator paper as appropriate and winding the tab terminal. In an electrolytic capacitor in which the protruding tab terminals are respectively connected and fixed to external terminals led out through a sealing plate, an anode foil and a cathode are provided on the upper side of the capacitor element from which the two electrode tab terminals are led out. An electrolytic capacitor, wherein the level position of the foil is set to be the same, and the width in the width direction of the anode foil is set relatively longer than the cathode foil on the bottom side of the capacitor element.