DE102019105452A1 - Cylindrical capacitor can and electrical capacitor with a cylindrical capacitor can - Google Patents

Abstract

The invention relates to a cylindrical capacitor can with a bottom jacket and a cup base, wherein in the transition area between the cup jacket and the cup base, an edge reinforcement is formed on the inner circumference and directed towards the inside of the cup, the top of which forms a support surface to keep the rest of the cup base free of mechanical loads, the edge reinforcement over its inner circumferential course has interruptions, notches, slots, incisions or gaps, which run in the direction of the cup base. The capacitor can according to the invention is used to accommodate one or more capacitor windings, with a base insulating cap used for this purpose being supported on the support surface, resulting in the desired mechanical freedom from loads of the cup base in the remaining floor area.

Description

The invention relates to a cylindrical capacitor can with a can shell and a can base according to claim 1, as well as an electrical capacitor with a cylindrical capacitor can, consisting of a can cover and a can bottom, at least one capacitor winding inserted in the capacitor can, a base insulating cap which surrounds a lower end of the capacitor winding and the capacitor winding leads in the capacitor can, a connection terminal and a lid which closes the can pressure-tight according to claim 2.

From the DE 10 2005 018 339 A1 an arrangement with a capacitor module and a method for its operation are previously known. In order to achieve particularly safe operation of such an arrangement, it is proposed that the arrangement have a safety device connected to the at least one capacitor, which monitors the operating state of the capacitor or the capacitor module and switches to a safety operating mode in the event of an operating state identified as unsafe .

The safety device has a strain measuring device that measures the spatial extent of the at least one capacitor or the spatial extent of the capacitor module and is designed such that the safety operating mode starts when a predetermined maximum strain measurement value is exceeded.

The strain gauges are designed so that they completely encompass the capacitor housing.

When setting up according to DE 10 2008 062 656 A1 which comprises a capacitor module, it is proposed that a housing is provided which accommodates the capacitor cells of the capacitor module, the housing having a capacitor chamber which accommodates the capacitor cells and which is sealed in a pressure-tight manner. An internal pressure of the capacitor chamber is detected by a pressure sensor to determine whether one of the capacitor cells is damaged.

For the capacitor with protective device, see DE 10 2015 215 729 A1 it is proposed to detect a fault condition that the capacitor has such a tight housing that the volume of the housing changes in the event of a fault, the change in the volume of the housing being detectable by a protective device.

For this purpose, a disengageable volume is integrated into the capacitor housing through structural measures. This integration takes place through shaping. The shape of the capacitor housing is designed in such a way that an increase in pressure in the interior of the capacitor causes the housing to increase in volume.

Embossing, beads, expansion joints or corrugated pipes should be suitable for this. The integration can also be made through the material properties of the housing. In this regard, the housing is formed by a material with such a material property that an increase in pressure inside the capacitor causes an increase in volume of the housing.

In order to generate a change in volume with increasing pressure inside the capacitor, different material thicknesses or strengths in the structure of the capacitor should be particularly suitable. As is known, there are two fundamentally problematic scenarios in the case of film capacitors with a dielectric made of plastic. A first problem is the failure due to low impedance, i.e. due to a short circuit. A short circuit can be controlled with the usual protective functions, in the simplest case a fuse. Somewhat more problematic is a so-called high-impedance failure due to aging processes. This can lead to increasing electricity heat losses in the condenser. The rise in temperature can cause plastic parts of the capacitor to melt and pyrolysis processes can take place. This creates gases. For the above reason, typical cup capacitors are designed to be pressure-tight, in particular gas-tight, in order to prevent escaping gases from forming an explosive mixture in connection with oxygen.

In order to secure the capacitor in the event of such a fault, which leads to an increase in pressure, so-called overpressure breakaway devices are used. When gas is formed inside the capacitor cup, these lead to a movement of the connections of the capacitor, so that the tear-off protection is triggered. The capacitor is thus separated from its voltage source. A further introduction of energy into the condenser and a further increase in pressure are avoided.

Another possibility for recognizing the onset of gas formation is to detect the internal pressure of the condenser, as already described above. Overpressure switches inside the condenser detect when a target internal pressure value is exceeded and provide an error message or shutdown.

Overpressure switches or corresponding sensors in the interior of the capacitor, as well as tear-off protection located inside, lead to impedance problems and to manufacturing-related expenses and thus higher costs.

From the above, it is the object of the invention to provide a further developed capacitor can and an electrical capacitor with such a capacitor can, which is designed so that with an external sensor or an external switching device, an overpressure in the capacitor is particularly easily detected and for evaluating error states or Can be used to switch off the capacitor or capacitors. It is important to design the structure of the capacitor can in such a way that the position of the capacitor coil in the can and thus also in the event of a pressure increase
the relevant connector, connection parts and similar means are not changed, so that a defined, in particular impedance-side, state is maintained.

The object of the invention is achieved with a capacitor can in accordance with the teaching of claim 1 and with an electrical capacitor in accordance with the combination of features in accordance with claim 2, the subclaims representing at least useful configurations and developments.

The cylindrical capacitor can according to the invention is based on a known can shell and a can bottom which is usually formed in one piece or integrally.

In the inner transition area between the cup shell and the cup base, an edge reinforcement is formed on the inside circumference and directed towards the inside of the cup, the top of which forms a support surface in order to keep the rest of the cup base free of mechanical load.

The edge reinforcement has interruptions, notches, slots, incisions or gaps or the like over its inner circumferential course, which run in the direction of the cup base.

These interruptions do not lead to a mechanical weakening of the base, but only serve to equalize the pressure inside a capacitor implemented on the basis of the cup according to the invention.

The electrical capacitor according to the invention is based on a cylindrical capacitor can consisting of a can jacket and a can bottom.

At least one capacitor winding is used in the capacitor can. In this regard, a bottom insulating cap is used that engages around a lower end of the capacitor can and guides the capacitor winding in the capacitor can.

There is also a connection terminal and a lid that closes the cup pressure-tight.

According to the invention, the transition area between the cup shell and the cup base has an edge reinforcement on the inner circumference and directed towards the inside of the cup, the top of which forms a support surface for the base insulating cap, so that the rest of the cup base is kept mechanically load-free.

The edge reinforcement has interruptions, notches, slots, incisions or gaps over its inner circumferential course, which run in the direction of the cup base.

Accordingly, the bottom insulating cap with the coil is supported on the support surface and the interruptions bring about the desired pressure equalization over the entire volume of the inside of the cup.

When the internal pressure in the cup increases, the bottom of the cup is subject to deformation, which can be recognized by a sensor system which is arranged on the outside of the capacitor.

In one embodiment, the interruptions in the edge reinforcement run uniformly distributed on the inner circumference.

The support surface of the edge reinforcement is designed essentially as a flat surface and in this respect corresponds to the underside of the bottom insulating cap.

The bottom insulating cap has an outer bevel on its underside, so that the pressure equalization channels are not covered in an undesirable manner in the form of the aforementioned interruptions.

The sensor system is e.g. designed as a switch which is in operative connection with the bottom outside.

The sensor system can also be an optical scanning device that responds to a deformation of the cup base.

In the unpressurized state, the bottom of the cup has an inner curvature and therefore runs concave. As the pressure rises, the bottom of the cup deforms in the convex direction, that is, in the sense of an outer curvature that can be scanned accordingly.

The deformation of the bottom of the cup in the convex direction can in this respect be detected by a button, a safety circuit being able to be triggered via the button.

If a larger number of capacitors of the construction according to the invention are arranged in an electrical device, the corresponding sensor system, in particular the mentioned switch or button, can continue to be used after a defective capacitor has been replaced.

The invention will be explained in more detail below with the aid of an exemplary embodiment and with the aid of figures.

• 1 einen Längsschnitt durch einen erfindungsgemäßen zylindrischen Kondensatorbecher mit nach innen gerichteter, gewölbter Randverstärkung;
• 2 eine Draufsicht in Richtung Innenseite eines Kondensatorbechers mit der Schnittlinie A-A zur Definition des Schnittes gemäß 1;
• 3 einen Längsschnitt durch einen elektrischen Kondensator mit dem erfindungsgemäßen Kondensatorbecher und dort erkennbarem Kondensatordeckel, Anschlussterminal, Innenverdrahtung und Bodenisolierkappe;
• 4 eine Detaildarstellung des unteren Endes des Kondensators gemäß 3 mit Bodenisolierkappe, Wickel, Becherboden und Randverstärkung;
• 5 und 6 beispielhafte Darstellungen der Verformung des Becherbodens im Ergebnis einer Druckeinwirkung von konkav (druckfrei) gemäß 5 bis zu konvex (druckbelastet) nach 6, wobei die unteren Darstellungen in den 5 und 6 die Schnittverläufe A-A zur Definition der Ansichten in den oberen Darstellungen repräsentieren.

Here show:

• 1 a longitudinal section through a cylindrical capacitor can according to the invention with inwardly directed, curved edge reinforcement;
• 2 a plan view in the direction of the inside of a capacitor can with the section line AA to define the section according to 1 ;
• 3 a longitudinal section through an electrical capacitor with the capacitor can according to the invention and there recognizable capacitor cover, connection terminal, internal wiring and base insulating cap;
• 4th a detailed representation of the lower end of the capacitor according to 3 with base insulating cap, wrap, cup base and edge reinforcement;
• 5 and 6th exemplary representations of the deformation of the cup base as a result of a pressure effect of concave (pressure-free) according to FIG 5 up to convex (pressure loaded) after 6th , the figures below in the 5 and 6th represent the sections AA for defining the views in the representations above.

The capacitor can according to the invention is based on a cylindrical design with a can jacket 1 and a cup base 2 out.

In the transition area between the cup shell 1 and cup base 2 is on the inside and to the inside of the cup 3 directed, an edge reinforcement 4th formed, the top of which has a support surface 5 forms to the rest of the cup base 2 to be kept mechanically load-free if there is a corresponding capacitor winding and base insulating cap inside the capacitor can.

The edge reinforcement 4th has interruptions, for example in the form of notches, over its course on the inner circumference 6th or the like, which in the direction of the cup base 2 run away.

The bottom of the cup 2 is arched inward in the unpressurized state, that is, it shows according to the sectional view 1 a concave shape viewed from the bottom of the cup.

According to the representations 3 and 4th , which show a longitudinal section through an electrical capacitor with a cylindrical capacitor can, the basic structure of an electrical capacitor of the type relevant here can now be seen.

In the condenser cup that is made from the cup jacket 1 and cup base 2 exists, one or more electrically interconnected windings 7th used.

The outside diameter of the windings 7th is smaller than the inner diameter of the corresponding capacitor can.

At the lower end of the lower capacitor winding 7th comes a bottom insulating cap 8th for use, which, as shown in detail in the figure, the lower end of the winding 7th encompasses and insofar as the winding leads in the capacitor can.

One lid 11 forms a tight seal for the capacitor can. There are electrically isolated connection terminals in the cover 9 that have a wiring 10 with the respective wrap 7th are contacted.

In the transition area between the cup shell and the cup base 2 there is also an edge reinforcement on the inside circumference and towards the inside of the cup 4th recognizable, the top of which is a support surface 5 for the floor insulation cap 8th forms.

The notches 6th in connection with a bevel on the underside of the floor insulation cap 8th pressure equalization across the entire cup volume.

In that the entire capacitor winding 7th with recourse to the bottom insulating cap 8th on the support surface 5 the condenser cup is supported, the cup bottom remains 2 mechanically load-free. The bottom of the cup 2 is only loaded with forces in the event of overpressure due to malfunction of the capacitor, as can be seen from the synopsis of the 5 and 6th can be understood.

You now arrange on the outside near the bottom of the cup 2 a switching device, for example a button, is easily activated in the event of a pressure increase due to the deformation of the bottom of the cup 2 this abnormal state of the corresponding capacitor can be recognized and a switching device can be triggered and appropriate signaling based on the error state can be carried out.

From the 2 as well as the views towards the inside of the cup (lower illustrations according to 5 and 6th ) it can be seen that there are notches or interruptions 6th the edge reinforcement 4th extend on the inside circumference and run essentially evenly distributed.

The deformation of the bottom of the cup 2 , which is completely mechanically load-free in normal operation, is an indicator function with regard to an increase in pressure in the capacitor. Since all other components located within the capacitor cup, in particular the capacitor winding (s), are supported on the edge reinforcement with the aid of the bottom insulating cap, it occurs in the case of these components, this does not lead to an undesirable change in position and thus to further possible damage due to the breaking of electrical connections along with sparking and the resulting dangers.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102005018339 A1 [0002]
• DE 102008062656 A1 [0005]
• DE 102015215729 A1 [0006]

Claims (9)

Cylindrical capacitor beaker with a beaker jacket (1) and a beaker base (2), characterized in that in the transition area between the beaker jacket (1) and the beaker base (2) an edge reinforcement (4) is formed on the inner circumference and directed towards the inside of the beaker (3), the top of which has a Forms support surface (5) to keep the rest of the cup base (2) mechanically load-free, the edge reinforcement (4) having interruptions, notches, slots, incisions or gaps (6) over its inner circumferential course, which run in the direction of the cup base (2) . Electrical capacitor with an, in particular cylindrical, capacitor can, consisting of a can jacket (1) and a can base (2), at least one capacitor winding (7) inserted in the capacitor can with a base insulating cap (8) which surrounds a lower end of the capacitor winding (7) and leads the capacitor winding (7) in the capacitor cup, a connection terminal (9) and a cover (11) which closes the capacitor cup pressure-tight, characterized in that in the transition area between the cup shell (1) and the cup base (2) on the inside circumference and to the cup interior (3) directed, an edge reinforcement (4) is formed, the top of which forms a support surface (5) to keep the rest of the cup base (2) mechanically load-free, the edge reinforcement (4) being interrupted, notches, slots, incisions or gaps over its inner circumference (6), which run in the direction of the cup base (2), the base insulating cap continues (8) is supported on the support surface (5), the interruptions (6) allowing pressure equalization over the entire volume of the inside of the cup and the cup base (2) being subject to deformation when the internal cup pressure increases, which can be detected or recognized by a sensor system. Electric capacitor after Claim 2 , characterized in that the interruptions (6) of the edge reinforcement (4) run uniformly distributed on the inner circumference. Electric capacitor after Claim 2 or 3 , characterized in that the support surface (5) is designed essentially as a flat surface. Electrical capacitor according to one of the Claims 2 to 4th , characterized in that the bottom insulating cap (8) has a circumferential bevel on its underside. Electrical capacitor according to one of the Claims 2 to 5 , characterized in that the sensor system is designed as a switch which is in operative connection with the outside of the bottom of the cup base (2). Electrical capacitor according to one of the Claims 2 to 5 , characterized in that the sensor system is designed as an optical scanning device for the cup base (2). Electrical capacitor according to one of the Claims 2 to 7th , characterized in that the cup base (2) has an inner curvature in the pressure-free state and is concave, with the beaker base (2) deforming in the convex direction in the sense of an outer curvature as the pressure in the capacitor cup increases. Electric capacitor after Claim 8 , characterized in that the deformation of the cup base (2) in the convex direction is detected by a button, a safety circuit being triggered via the button.

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