JPH0414912Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a case-exterior type capacitor in which a metallized film capacitor element is housed in an exterior case, and is particularly useful in cases where the capacitor element eventually breaks down. The present invention relates to a case-exposed capacitor equipped with a safety mechanism that can cut off power supply to the element and prevent dangers such as fire and explosion.

[Conventional technology] Conventionally, case-exposed capacitors, in which a metallized film capacitor element is housed in an outer case, have excellent self-healing properties that allow the capacitor element to recover its insulation properties even if a partial breakdown occurs in the capacitor element. For,
It is widely used in a variety of electrical and electronic equipment, including household appliances.

Even with these excellent characteristics, metallized film capacitor elements may be damaged if abnormal surge voltages are applied to them many times or if they are used continuously for a long period of time.
The frequency of occurrence of partial dielectric breakdown increases due to deterioration of the dielectric film that constitutes the capacitor element, and the deterioration is further accelerated by the partial discharge and temperature rise accompanying dielectric breakdown, eventually leading to ultimate breakdown. becomes. However, even in this state, the metallized film capacitor element does not completely short-circuit due to its self-recovery function, so external safety devices such as current fuses and breakers cannot operate, and power continues to be supplied to the capacitor element. The state remains as it is. As a result, the dielectric film is decomposed due to successive partial discharges and abnormal temperature rises, generating flammable gas, which poses a risk of ignition or explosion.

As a countermeasure for this, for example, the outer case has a sealed structure and is equipped with a safety device that uses the expansion of the case due to gas pressure to cut the conductive path, or one that detects abnormal current, temperature, or generated gas and cuts off the power supply. However, since these devices are equipped with a special safety device, the structure becomes complicated, the manufacturing process becomes complicated, the manufacturing cost increases, and the external size increases. There was a problem.

Therefore, a case is made in which lead wires, external terminals, etc. made of an elastic material are connected to the end face of a capacitor element housed in an exterior case with a low melting point metal such as solder, resisting the elastic force. External type capacitors have appeared.

This is because the low melting point metal melts due to an abnormal temperature rise in the capacitor element, and as a result, the external terminals etc. separate from the capacitor element due to elastic force, cutting off the power supply to the capacitor element. It was possible to achieve high safety with a simple configuration.

[Problem to be solved by the invention] However, in the case of the above-mentioned conventional case exterior type capacitor, no special consideration was paid to the internal structure of the case, so if it is placed at an angle, it may melt. The low melting point metal on one external terminal side may flow into the other external terminal side, causing a short circuit between both external terminals, or once the low melting point metal has melted and the external terminal has separated from the end surface of the element,
There was a risk that the low melting point metal would flow between the external terminal and the end face and reconnect them.

This invention was devised in view of the above points,
The purpose of the present invention is to realize a case-exterior type capacitor with a simple structure, without the risk of fire or explosion, and without the risk of short-circuiting between external terminals or reconnection between external terminals and end faces after activation of a safety mechanism. .

[Means for solving the problem] In order to achieve the above object, the present invention includes an outer case, a metallized film capacitor element housed in the outer case, and an external terminal formed of an elastic material. With one end of the external terminal biased toward the side wall inside the exterior case, the external terminal is connected to the end face of the metallized film capacitor element using a low melting point metal, and the other end of the external terminal is connected to the end face of the metallized film capacitor element with a low melting point metal. In the case-exposed capacitor that is led out of the case, a partition wall is formed between the external terminals in the exterior case, a protrusion is provided on the bottom surface of the exterior case, and the capacitor element is mounted on the protrusion. The gist of the present invention is a case-exterior-type capacitor characterized in that a space is formed between the end surface of the capacitor element and the bottom surface inside the exterior case by arranging the capacitor element.

[Function] If the metallized film capacitor element described above eventually breaks down, the low melting point metal will melt due to the rise in internal temperature, and the external terminals connected by the low melting point metal will become damaged due to the elastic material. It detaches from the electrode due to the biasing force. Therefore, the external terminal and the electrode are electrically opened, and power supply to the capacitor element is cut off.

Since the external terminals are separated by the partition wall, even if the external terminals are installed at an angle, molten low-melting point metal will not flow into the other external terminal side. There will be no short circuit caused by molten low melting point metal.

Further, since the molten low-melting point metal accumulates in the space, it does not flow between the external terminal and the end face once separated and reconnect them.

[Example 1] Hereinafter, an example of the present invention will be described based on the accompanying drawings.

Figure 1 shows one embodiment of the present invention.
Figure A is a schematic sectional view thereof, and Figure 1B is a schematic sectional view showing a state in which the safety mechanism is in operation. The case exterior type capacitor 1 according to this embodiment is a metallized film capacitor formed by laminating and winding a metallized film in which a metal such as tin or aluminum is deposited on a dielectric film made of a synthetic resin such as polyester or polypropylene. It has an element 2, and electrodes 3, 3 are formed on both end surfaces of the metallized film capacitor element 2 by applying metallicon. Furthermore, one ends of the external terminals 5, 5 attached to the terminal board 4 are connected to the electrodes 3, 3, and are connected so that a gap is formed between the external terminals 5, 5 and the side wall of the exterior case 6. The above terminal board 4 is then stored in the exterior case 6.
is engaged with the exterior case 6, and the external terminals 5, 5 are connected to each other.
It has a structure in which the other end is guided out of the outer case 6.

The external terminals 5, 5 are made of a conductive elastic material such as CP wire or phosphor bronze, and are bent into a dogleg shape, and then pushed back in the opposite direction to the outer case. It is welded to the electrodes 3, 3 in a state where it is biased toward the side wall inside the electrode 6.
Further, the electrodes 3, 3 are formed by thermal spraying a low melting point metal such as low melting point solder, and the material of the metal is selected according to the safety mechanism operation setting temperature.

The exterior case 6 is made of a heat-resistant synthetic resin such as polyphenylene sulfide or polybutylene terephthalate, and protrusions 7, 7 are formed on the bottom surface inside the exterior case 6. The terminal plate 4 is made of a heat-resistant insulating material such as frenol, and a partition wall 8 is formed between the external terminals 5 on the inner surface thereof.

Since the metallized film capacitor element 2 is disposed on the projections 7, 7, the metallized film capacitor element 2 is held on the bottom surface of the exterior case 6 in a non-adherent state. As a result, a space is formed between the metallized film capacitor element 2 and the bottom surface, and the molten low melting point metal accumulates in this space. Therefore, the external terminal 5 once removed
However, the metalized film capacitor element 2 is not reconnected to the end face of the metallized film capacitor element 2 by the molten low melting point metal. Further, since the external terminals 5, 5 are separated by the partition wall 8, the molten low melting point metal flows into the other external terminal, and the external terminals 5, 5 are separated.
There will be no short circuit between the two.

[Embodiment 2] Fig. 2 shows another embodiment of the present invention, in which Fig. 2A is a schematic sectional view thereof, and Fig. 2B is a schematic sectional view showing a state in which the safety mechanism is activated. In this embodiment, on both end surfaces of the metallized film capacitor element 2,
An electrode 3 is formed by thermal spraying an ordinary metallicon material made of lead with trace elements added, and an external terminal 5 is connected to the electrode 3 by a connecting member 9 made of a low-melting point metal such as low-temperature solder. . Other structures and operations are substantially the same as in the first embodiment.

In addition, in the embodiment described above, the external terminal 5
Although the case where a safety mechanism formed of an elastic material and connected with a low melting point metal is provided on both end faces of the capacitor element 2 is shown, it may also be provided on only one side depending on the size and purpose of the capacitor. The following effects can be obtained.

[Effects of the invention] As detailed above, the case exterior type capacitor of the present invention is equipped with a safety mechanism in which the external terminal made of an elastic material is connected to the end face of the metallized film capacitor element using a low melting point metal. The heat generated by the eventual destruction of the capacitor element melts the low melting point metal and detaches the external terminal, thereby cutting off the power supply and reliably preventing ignition or explosion. In addition, the above-mentioned safety mechanism can be formed by only partially changing the materials of ordinary capacitor components, so it has a simple and compact structure, and it also has various practical values such as being easy to manufacture and providing at low cost. It is something that you have.

In addition, since the external terminals are separated by the partition wall, molten low-melting point metal does not flow into the other external terminal side, and short circuits caused by molten low-melting point metal between the external terminals are prevented. can.

Furthermore, since the molten low-melting point metal accumulates in the space formed between the end surface of the metallized film capacitor element and the bottom surface inside the outer case, the molten low-melting point metal will accumulate between the external terminal and the end surface once removed. This can prevent reconnection.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the present invention, FIG. 1A is a schematic sectional view thereof, FIG. 1B is a schematic sectional view showing the state in which the safety mechanism is activated, and FIG. 2 is another embodiment of the present invention. An example is shown, and FIG. 2A is a schematic sectional view thereof, and FIG. 2B is a schematic sectional view showing a state in which the safety mechanism is activated. DESCRIPTION OF SYMBOLS 1... Case exterior type capacitor, 2... Metallized film capacitor element, 3... Electrode, 4... Terminal plate, 5... External terminal, 6... Exterior case, 7...
... protrusion, 8 ... partition, 9 ... connection member.

Claims (1)

[Scope of utility model registration request] It has an outer case, a metallized film capacitor element housed in the outer case, and an external terminal formed of an elastic material, and one end of the external terminal is biased toward a side wall inside the outer case. In the state
In a case-exterior type capacitor, which is connected to the end face of the metallized film capacitor element with a low melting point metal, and the other end of the external terminal is led out of the exterior case, there is a connection between the external terminals within the exterior case. By forming a partition wall, providing a protrusion on the bottom surface of the exterior case, and arranging the capacitor element on the protrusion, there is a gap between the end surface of the capacitor element and the bottom surface of the exterior case. A case-exterior type capacitor characterized by the formation of a space.