Capacitor arrangement and method for producing a capacitor arrangement

The present invention relates to a capacitor arrangement having a capacitor and a first terminal plate and a second terminal plate. The capacitor has a first contact face and a second contact face arranged opposite one another. The terminal plates are each connected to one of the contact faces and have protrusions on one end suitable for engaging in recesses in a power rail.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. National Phase application submitted under 35 U.S.C. §371 of Patent Cooperation Treaty application serial no. PCT/DE2009/001398, filed Oct. 8, 2009, and entitled CAPACITOR ARRANGEMENT AND METHOD FOR PRODUCING A CAPACITOR ARRANGEMENT, which application claims priority to German patent application serial no. 10 2008 050 452.1, filed Oct. 8, 2008, and entitled Kondensatoranordnung and Verfahren zum Herstellen einer Kondensatoranordnung.

Patent Cooperation Treaty application serial no. PCT/DE2009/001398, published as WO 2010/040343, and German patent application serial no. 10 2008 050 452.1, are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a capacitor arrangement and a method for manufacturing a capacitor arrangement.

BACKGROUND

EP 1 632 117 B1 relates to an electronic module for switching electric power. The module has two power supply rails spaced a distance apart from one another and a capacitor arrangement which bridges the two power supply rails.

With the known approaches, so-called module capacitors are constructed on a separate circuit board and connected to power modules by means of connections of a suitable length. In addition to the additional space required for the circuit board, an additional circuit board layout is also necessary. In addition, this also results in a poor utilization of space. The circuit board is also associated with additional weight. The long connections result in a higher inductance, which in turn results in limiting the switching frequencies of the power modules.

SUMMARY AND DESCRIPTION

The object of the present invention is to create an improved capacitor arrangement and an improved method for manufacturing a capacitor arrangement.

This object is achieved by a device as described and claimed herein as well as a method as described and claimed herein.

The present invention is based on the finding that a capacitor can be applied to a substrate of a power module through the use of specially shaped capacitor terminal plates without any loss of lifetime. Damage to the capacitor due to high temperature stress due to the soldering process can be prevented according to the invention. In this way it is possible to ensure capacitor availability after the manufacturing process.

Furthermore, a compact design of the power module optimized with regard to installation space is made possible through the special capacitor terminal plates. Therefore, contacts that have been optimized with regard to installation space and weight and in particular a low inductance contacting of the module capacitor on the power module or electronic power module can be performed. This leads to a low parasitic inductance between the power elements and the capacitor. A better thermal connection of the capacitor to a module cooler is also possible.

The present invention creates a capacitor arrangement having the following features:

a capacitor having a first contact face and a second contact face, where the first and second contact faces are arranged opposite one another;

a first terminal plate which is connected to the first contact face, whereby the first terminal plate has on one end protrusions suitable for engaging in recesses in a first angled area of a first power rail of an electronic power module; and

a second terminal plate which is connected to the second contact face whereby the second terminal plate has on one end protrusions suitable for engaging in recesses in a first angled area of a second power rail of the electronic power module.

The capacitor may be suitable for use in a power module. Accordingly, the power rails may be designed to provide an electrical connection between the capacitor and a substrate of the power module. In particular the power rails may be so-called power bus bar terminals. The recesses in the power rails may be implemented in the form of grooves or through-holes. A direct connection of the module capacitor, which may consist of the capacitor and the terminal plates, to the power module is advantageously possible. Therefore, a low inductance and a compact design can be achieved. This is possible due to the special inventive connection geometries for the module capacitor and the power rails. A direction connection of the module capacitor to the electronic power module may be achieved in particular through the special terminal plates and power rails. The capacitor can thus be arranged as close as possible to the electronic power module.

The contact faces and the terminal plates may be aligned in parallel to one another. In this way the contact faces can be connected to the terminal plates over the full area. The capacitor may be arranged in a space-saving manner in parallel above the substrate. Thus the terminal plates which are arranged perpendicularly with respect to the alignment of the capacitor permit the shortest possible connection of the capacitor to the substrate.

The capacitor arrangement may have the first and second power rails whereby the power rails may be aligned in parallel to the terminal plates and the protrusions of the terminal rails may engage in the recesses in the power rails. The inventive capacitor arrangement may thus replace known module capacitors without necessitating adjustments in the substrate, for example, the power module.

The capacitor arrangement may have soldered connections and/or welded connections, which are designed to connect at least a few of the protrusions on the first terminal plate to the first power rail and to connect at least a few of the protrusions on the second terminal plate to the second power rail. Soldering of the grooved capacitor terminal plates to the power rail terminals is thus possible.

The soldered connections may advantageously each be arranged on a side of the power rail opposite the capacitor. The soldered connections can thus be created easily and in such a way that they are accessible from the outside.

According to one embodiment, the terminal plates may each have an angled area, which is designed in each case to be adjacent to a second angled area of the power rails in a form-fitting manner. The angled areas can stabilize the construction of the capacitor arrangement and represent an additional electrical contact.

Furthermore, the capacitor arrangement may have screw connections, which are designed to connect each of the angled areas of the terminal plates to the second angled areas of the power rails. A simple connection of the module capacitor to the power rails can thus be created. The angled areas of the module capacitor can then be bolted to an intermediate circuit.

The present invention also creates a method for manufacturing a capacitor arrangement comprising the following steps:

Providing a capacitor having a first contact face and a second contact face, whereby the first and second contact faces are arranged opposite one another;

Providing a first power rail and a second power rail each having a first angled area having recesses;

Providing a first terminal plate and a second terminal plate each having on one end protrusions suitable for engaging in the recesses in the power rails;

Connecting the terminal plates to the contact faces so that the first terminal plate is aligned toward the first contact face and the second terminal plate is aligned to the second contact face; and

Connecting the terminal plates to the power rails so that the first terminal plate is aligned in parallel to the first power rail and the second terminal plate is aligned in parallel to the second power rail and the protrusions on the first terminal plate engage in the recesses in the first power rail and the protrusions on the second terminal plate engage in the recesses in the second power rail.

The present invention thus creates a manufacturing concept for integration of capacitors on hybrid power modules which is based on a special embodiment of the capacitor terminals and the power rails. An inventive process description here defines how the special capacitor embodiment is attached to the substrate. The inventive manufacturing process proceeds in such a way that the power rails are first applied to the substrate of the power module without a capacitor. In a subsequent step, the module capacitor consisting of the capacitor and the terminal plates is then connected to the power rails by means of simple soldering.

The inventive method may include a step of joining the power rails to a substrate before the terminal plates are connected to the power rails. Due to the proposed sequence, it is possible to prevent a great influence of temperature on the capacitor when the power rails are soldered to the substrate. The substrate may be the substrate of the power module. The substrate may be embodied as a circuit board.

This method may comprise a step of creating soldered joints which are embodied to connect at least a few of the protrusions on the first terminal plate to the first power rail and to connect at least a few of the protrusions on the second terminal plate to the second power rail. In this way the capacitor arranged between the terminal plates can be connected to the power rails, such that a temperature influence on the capacitor can again be minimized.

According to the invention, the terminal plates may each have an angled area, which is adjacent to a second angled area of the power rails in a form-fitting manner, and the method may comprise a step of creating a first screw connection for connecting the angled area of the first terminal plate to the second angled areas of the first power rail and a second screw connection for connecting the angled area of the second terminal plate to the second angled areas of the second power rail. The screw connection allows an independent or additional electrical and mechanical connection of the capacitor in addition to the soldered joint.

DETAILED DESCRIPTION

In the following description of the preferred exemplary embodiments of the present invention, the same or similar reference numerals are used for the similarly acting elements depicted in the various drawings, thereby omitting a repeated description of these elements.

FIG. 1shows a capacitor arrangement according to an exemplary embodiment of the present invention. This shows in particular a final modular diagram without a housing. The capacitor arrangement has a capacitor100, a first terminal plate102and a second terminal plate103. The terminal plates102,103are each connected to contact faces of the capacitor100. The capacitor arrangement may also have a first power rail105and a second power rail106. The power rails105,106may be arranged on a substrate108, for example, the substrate of a power module and may be connected to the terminal plates102,103. Thus the capacitor100may be arranged between the terminal plates102,103and the terminal plates may in turn be arranged between the power rails105,106. According to the diagram inFIG. 1, the capacitor100is aligned in parallel and above a surface of the substrate108.

The contact faces of the capacitor100may be aligned opposite and in parallel with one another. The first contact face is connected to the first terminal plate102and the second contact face is connected to the second terminal plate103. Thus the terminal plates102,103may be aligned in parallel to the contact faces. The terminal plates102,103may be made of metal. The terminal plates102,103and the contact faces may be soldered to create an electrical and mechanical connection. Known soldering methods may be used to create the soldered connections.

For connecting the terminal plates102,103to the power rails105,106, the terminal plates102,103each have protrusions110on the end facing the substrate108. The protrusions110may be embodied by rectangular recesses in the terminal plates102,103. The protrusions110may be embodied over the entire length of the end of the terminal plates102,103or only in partial areas of the terminal plates102,103.

The power rails105,106may be made of metal and may be adapted to the terminal plates102,103in size and shape. Thus the terminal plates102,103may be in direct contact with the power rails105,106. The power rails105,106may have a bend on the end facing the substrate108. According to this exemplary embodiment, the power rails105,106are bent at a right angle, each in the direction of the adjacent terminal plates102,103. In the area of the bend the power rails105,106have recesses. The protrusions110on the terminal plates102,103may engage in the recesses. Therefore the size and shape of the recesses may be adapted to those of the protrusions110. In this way the terminal plates may be inserted from above along the power rails105,106with the protrusions110into the recesses and then lie on the angled area of the power rails105,106. The power rails105,106may have terminal contacts112in the angled area. The power rails105,106may be connected electrically and mechanically to the substrate108by means of known methods, for example, soldering methods by way of the terminal contacts112.

The terminal plates102,103and the power rails105,106may each have an angled area114on the end opposite the substrate108. According to this exemplary embodiment the angled areas114are shaped by protrusions on the terminal plates102,103and the power rails105,106. These protrusions are bent at a right angle on the side facing away from the capacitor100to create the angled areas114. The areas114of the terminal plates102,103and of the power rails105,106that are angled at the top may each overlap and thus form bundles of laminations. The bundles of laminations may have a hole for receiving a screw.

FIG. 2shows the inventive capacitor arrangement during production, in which the module capacitor consisting of the capacitor100and the terminal plates102,103soldered to the capacitor100is subsequently inserted between the power rails105,106. “Subsequently” here means that the power rails105,106have first been connected to the substrate108. In addition to the features already described on the basis ofFIG. 1,FIG. 2shows the recesses211in the power rails105,106. According to this exemplary embodiment, the recesses211are rectangular holes, which are arranged in the area of the rectangular bends in the power rails105,106and extend on both sides of the bend.

To manufacture the inventive capacitor arrangement, first the capacitor100, the power rails105,106and the terminal plate102,103may be provided. In one step of the method, the terminal plates102,103are connected to the contact faces of the capacitor100. A soldering operation may be used here. In another step of the method, the terminal plates102,103are joined to the power rails105,106. The joining may be accomplished by using a plug connection by means of the protrusions110and the recesses211, a soldered joint and additionally a screw connection of the angled areas114. The angled areas114may be formed before or after joining the capacitor module100,102,103to the power rails105,106.

Thus, in order to integrate the capacitor100“into” the power module, the following steps are performed in a reasonable but freely selectable order. In one step of the method the terminal plates102,103for the capacitor100can be applied to the capacitor100according to a known procedure. To do so, the capacitor100may be assembled with specially shaped (grooved) terminal plates102,103. Furthermore, the power rails105,106may be applied to the substrate108by a known method. This may include applying the “metallic” power rails105,106to copper conductors on the carrier substrate108at a high temperature. A dummy capacitor including terminals may have already been positioned to maintain the subsequent distances or the correct positioning of the power rail terminals may be ensured by a corresponding soldering device. After the connections of the power rails have cooled, the actual capacitor100may be inserted together with the terminal plates102,103into the power rail grooves211and joined to the power rails105,106with the help of a known soldering method or welding method. In conclusion, the individual metal packages may be converted to the proper shape at the upper end accordingly and bolted to the intermediate circuit terminal. In doing so, the upper capacitor terminals114with the upper power rails terminals may be angled by 90° and then bolted to the intermediate circuit terminals. Thus, there can be a connection of the module capacitor to the power rail terminals by soldering the capacitor100and/or its terminals102,103without exposing the capacitor film to an excessively high temperature.

FIG. 3shows a diagram of the inventive capacitor arrangement from underneath. In particular this shows contact points on the module capacitor with the power rail106in a view from the outside. The contact points are located in the areas where the protrusions110of the terminal plate engage in the recesses in the power rail106. For joining the terminal plate to the power rail106the protrusions110may be soldered to the power rail106from the outside.

FIG. 4shows a diagram of the partial area of the inventive capacitor arrangement. In particular additional contact points between the module capacitor and the power rail105are shown in a view from the inside. The contact points are implemented by means of the terminal contacts112. The terminal contacts112are implemented as angled protrusions on the power rail105. The terminal contacts112may be in flat contact with a printed conductor of the substrate108and may be soldered to the printed conductor. The terminal contacts112may be bent several times, e.g., at a right angle to compensate for thermal and mechanical stresses.

FIG. 5shows a diagram of the inventive capacitor arrangement as part of an electronic power module. In particular this shows a schematic diagram of the electronic power module, which has the inventive capacitor arrangement. The electronic power module has a housing520. This housing520surrounds the capacitor of the capacitor arrangement at least partially. Furthermore, this shows a connecting line, which is connected to the capacitor arrangement by a screw connection.

FIG. 6shows a diagram of an inventive capacitor arrangement according to another exemplary embodiment of the present invention. The capacitor arrangement differs from the preceding exemplary embodiments in particular in the design of the power rails. This shows among other things the terminal plate603and a power rail606of the capacitor arrangement.

FIG. 7shows a diagram of the terminal plate603and the power rail606of the capacitor arrangement shown inFIG. 6. The power rail606has recesses into which the protrusions110of the terminal plate603can be inserted. To design the recesses, the power rail606may be punched repeatedly on three sides. The areas punched out form protrusions730which may be aligned parallel to the protrusions110on the terminal plate603. The protrusions110on the terminal plate603may protrude both laterally and longitudinally beyond the protrusions730on the power rail606. The areas not punched out of the power rail606are bent and may form the terminal contacts112at the ends. As an alternative to punching, the protrusions730may be created by cutting, lasering or by some other method.

The exemplary embodiments described here are selected only as examples and may be combined with one another. The capacitor, the terminal plates and the power rails may be embodied in the form shown or in another suitable form. Furthermore, a plurality of capacitors may also be used. The steps for integration of the module capacitor may also be performed in an order other than that described here.