JP2002260972A - Capacitor with protection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To actualize a capacitor with a protection device which speedily stops electric operation before the capacitor causes a shorted puncture becoming abnormal owing to an overcurrent and throws out the contents. SOLUTION: The capacitor with the protection device is formed by gathering and connecting lead tabs 2 led out of a capacitor element 1 to electrode tabs 7 less than the lead tabs 2 and then connecting them to an external terminal 5. The electrode tabs 7 are provided with a brittle part 8 which is fused by the heat generated if an abnormal current flows, and the brittle part 8 is fused before the capacitor itself bursts and its contents spill out to cut off the current supply to the capacitor and also speedily stops the electrical operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor, and more particularly to a capacitor provided with an open mode security device.

[0002]

2. Description of the Related Art In a conventional electrolytic capacitor, an anode foil subjected to an etching treatment is formed and an oxide film is formed on the surface of the foil. Then, the anode foil and the cathode foil are wound with a separator interposed therebetween to form a capacitor element. The capacitor element is impregnated with an electrolytic solution and stored in a bottomed cylindrical outer case to complete the electrolytic capacitor. When a current is passed through the electrolytic capacitor, the oxide film formed on the anode foil becomes an insulator and is charged between the electrodes, and the electrical operation of the electrolytic capacitor functions.

Further, a rating, which is an allowable voltage value of the electrolytic capacitor body, is set according to a voltage at the time of forming the anode foil. In other words, the maximum voltage value that can be applied to the electrolytic capacitor is set as the rating.However, even if a voltage higher than the rated value is applied, the safety of the electrolytic capacitor is ensured even if some voltage is applied. Have a predetermined voltage allowable margin.

[Problems to be solved by the invention]

[0004] However, when an abnormal voltage exceeding the voltage tolerance margin provided above the rating of the electrolytic capacitor is further applied, insulation breakdown of the oxide film formed on the anode foil of the electrolytic capacitor occurs to cause a short circuit. There were cases. Then, the excess current continues to flow through the short-circuited electrolytic capacitor, causing excessive heat generation and sometimes causing ignition of the electrolytic capacitor. Furthermore, the electrolytic capacitor itself bursts due to the inrush large current at the time of excessive voltage,
The element may jump out of the sealing part, or the outer case may tear, causing the contents such as electrolyte to scatter, causing a heavy load on electrical circuits such as home appliances where other electronic components are densely packed. .

[0005] Therefore, in the capacitor with a security device of the present invention, when the electrolytic capacitor is abnormal, the electrolytic capacitor which caused a short puncture or the like may cause excessive heat generation to ignite or the content of the electrolytic capacitor itself may be ruptured. An object of the present invention is to quickly stop the electrical operation of an electrolytic capacitor before jumping out.

[0006]

In order to achieve the above object, a capacitor element 1 having a plurality of lead tabs 2 led out from the same surface, and a bottomed cylindrical outer case 3 for accommodating the capacitor element 1 are provided. In a capacitor including a sealing member 4 for sealing the inside of the outer case 3 and an external terminal 5 formed so as to connect the front and back of the sealing member 4, two of the plurality of lead tabs are collected, The electrode tabs 7 are connected to a smaller number of electrode tabs 7 than the plurality of lead tabs 2, and the electrode tabs 7 are connected to the external terminals 5. Provided.

The fragile portion 8 has a cross-sectional area smaller than that of the electrode tab 7, so that the electrode tab 7 generates heat and is cut off.

In the present invention, the plurality of lead tabs 2 are led out from the respective electrodes of the anode and the cathode, and the plurality of lead tabs 2 are assembled and connected to a smaller number of electrode tabs 7 than the plurality of lead tabs. . Therefore, when an abnormal current such as overcurrent or reverse current flows through the capacitor,
The abnormal current flows from the plurality of lead tabs 2 to a smaller number of electrode tabs 7 than the plurality of lead tabs 2. The fragile portion 8 provided on the electrode tab 7 is further provided with a smaller cross-sectional area of the fragile portion 8 than the cross-sectional area of the electrode tab 7, and thus has a lower resistance than the electrode tab 7. The structure is large and easy to generate heat, so it is blown out. Therefore, when an abnormality occurs in the capacitor, the electric circuit can be immediately shut off, and the electric operation of the capacitor itself can be stopped.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment according to the present invention will be described below with reference to FIGS.

FIG. 1 is a front sectional view of a capacitor with a security device of the present invention, and FIG. 2 is a perspective view of a capacitor with a security device of the present invention, particularly near a lead tab.

As shown in FIG. 1, the capacitor with a security device according to the present embodiment accommodates a capacitor element 1 formed by winding an anode foil and a cathode foil via a separator paper in a cylindrical outer case 3 having a bottom. Then, the open end side is sealed by a sealing member 4 for sealing the inside of the outer case 3,
The outer case 3 is caulked by the curling process, and the inside of the outer case 3 is sealed.

The sealing member 4 has a double structure of a resin plate and a rubber plate, and a rubber plate is stuck on the upper surface of the resin plate. Property is obtained.

The sealing member 4 is formed with an external terminal 5 for electrically connecting the capacitor body and the busbar, and the external terminal 5 connects the front and back of the sealing member. It is formed as follows.

In particular, a plurality of lead tabs 2 of the present embodiment are led out of the capacitor element 1 from an anode and a cathode, respectively, and are assembled. In addition, as a consolidating means, there is a method in which a through hole is provided in each of the plurality of lead tabs 2, the external terminal 5 is passed through the through hole, and the head of the external terminal 5 is crushed and fixed. Also, a connection method by electric resistance welding, laser welding, ultrasonic welding, or the like is preferable, and the consolidation portion 6 may be formed by all or any method.

Then, one tab of the plurality of lead tabs 2 is extended from a portion where the plurality of lead tabs 2 are gathered to form an electrode tab 7. As shown in this embodiment of FIG. 1, one tab may be extended from the plurality of lead tabs 2 to form the electrode tab 7. However, the plurality of lead tabs 2 may be assembled to form another electrode tab 7 May be connected by welding or the like.

Further, an end 10 of the electrode tab 7 is connected to the external terminal 5 on the back side of the sealing member 4. At the end 10 of the electrode tab 7, a through hole 9 for connecting to the external terminal 5 is provided. Then, the external terminal 5 is passed through the through-hole 9 of the electrode tab 7, the head of the external terminal 5 is crushed, and the electrode tab 7 and the external terminal 5 are electrically connected.

The electrode tab 7 is provided with a fragile portion 8. It is preferable that the fragile portion 8 is disposed between a connecting portion between the electrode tab 7 and the external terminal 5 and a collecting portion 6 of the plurality of lead tabs 2.

That is, when an abnormal current such as an overcurrent flows through the capacitor, a plurality of lead tabs 2 respectively derived from the anode and the cathode of the capacitor element 1 are gathered to collect the current, and the plurality of lead tabs 2 are connected to each other. It reaches the connected electrode tab 7. And the abnormal current is
When the fragile portion 8 provided on the electrode tab 7 and having a smaller cross-sectional area than the electrode tab 7 reaches the fragile portion 8, the fragile portion 8 generates heat because the resistance of the fragile portion 8 is larger than that of the electrode tab 2. It has a structure in which the fragile portion 8 is blown. That is, since the abnormal current is converged from the plurality of lead tabs 2 derived from the capacitor element 1 to the fragile portion 8, the fragile portion 8 easily generates heat and is easily blown. As a result, the power supply to the capacitor was quickly cut off,
It is a security mechanism that can stop the electrical operation of the capacitor itself.

The sectional area of the fragile portion 8 is as follows.
It is sufficient that the cross-sectional area is smaller than the electrode tab 7, that is, it is desirable that the fragile portion 8 be larger than the resistance value of the electrode tab 7. The allowable overcurrent value can be set by adjusting the resistance value of the fragile portion 8 according to its width, material, and the like, and the timing of fusing the fragile portion 8 can be adjusted. This is excellent as a design item of the security mechanism of the capacitor.

FIG. 2 is a perspective view particularly showing the vicinity of the lead tabs. A plurality of lead tabs 2 respectively derived from the anode and the cathode are gathered from the capacitor element 1 so that a smaller number of electrode tabs than the plurality of lead tabs 2 are provided. 7 represents a structure connected to the device. In order to connect the end 10 of the electrode tab 7 to the external terminal 5 provided on the back side of the sealing member 4, a through hole 9 is provided in the end 10 of the electrode tab 7.

In the present embodiment, the electrode tab 7
Is formed by a notch.
The fragile portion 8 has a small cross-sectional area for the purpose of facilitating heat generation at the time of abnormal current of the capacitor, and the present invention is not limited to this. Any other structure may be used as long as the structure leads to fusing.

[0022]

According to the conventional electrolytic capacitor, when an abnormal condition such as an overcurrent occurs, the electrolytic capacitor causing a short puncture or the like causes excessive heat to ignite, or the content of the electrolytic capacitor itself bursts out by bursting. However, the capacitor with a security device of the present invention
A plurality of lead tabs 2 are led out of the capacitor element 1 to be assembled and connected to a smaller number of electrode tabs 7 than the plurality of lead tabs 2. The electrode tab 7 is provided with a fragile portion 8. When the electrolytic capacitor is abnormal as described above, the fragile portion 8 having a large resistance value generates heat and melts, so that the content of the electrolytic capacitor jumps out. In the open mode before, the power supply to the electrolytic capacitor body is cut off, and the electric operation can be stopped immediately. As a result, it is possible to prevent adverse effects on other electronic components that are densely installed.

As shown in FIG. 2, a capacitor security device is provided by a combination of a plurality of lead tabs 7, a smaller number of electrode tabs 7 than the plurality of lead tabs 2, and a fragile portion 8 provided on the electrode tab 7. Therefore, in manufacturing the capacitor with a security device of the present invention,
Not only can its structure be simplified, but also it can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a front sectional view of a capacitor with a security device according to the present invention.

FIG. 2 is a perspective view of the vicinity of a lead tab of the capacitor with a security device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Capacitor element 2 Plural lead tabs 3 Outer case 4 Sealing member 5 External terminal 6 Gathering part 7 Electrode tab 8 Weak part 9 Through hole 10 End part

Claims (2)

[Claims] 1. A capacitor element having a plurality of lead tabs extending from the same surface, a bottomed cylindrical outer case for accommodating the capacitor element, a sealing member for sealing the inside of the outer case, and the sealing member. And an external terminal formed so as to connect the front and back of the member, wherein the plurality of lead tabs are assembled and connected to fewer electrode tabs than the plurality of lead tabs, and the electrode tab is connected to the external terminal. Wherein the electrode tab is provided with a fragile portion which is melted off by heat generation. 2. The security device according to claim 1, wherein the fragile portion is a fragile portion having a cross-sectional area smaller than a cross-sectional area of the electrode tab, wherein the electrode tab generates heat and melts. With capacitor.