KR102326063B1 - Film capacitor module of inverter for vehicle - Google Patents

Abstract

A film capacitor module of an inverter for a vehicle is disclosed. The film capacitor module includes a plurality of film capacitor unit cells having a P-pole electrode and an N-pole electrode formed on both ends thereof in a form in which a pair of metallized films are wound, and the plurality of film capacitor unit cells formed on one end surface of the plurality of film capacitor unit cells. A P-pole bus bar coupled to the P-pole electrode, an N-pole bus bar coupled to the N-pole electrode formed on the other end surface of the plurality of film capacitor unit cells, an upper heat sink formed on the P-pole bus bar, and the N and a lower heat sink formed on the pole busbar.

Description

FILM CAPACITOR MODULE OF INVERTER FOR VEHICLE

The present invention relates to a film capacitor module, and more particularly, to a film capacitor module used as a DC-link capacitor of a vehicle inverter.

2. Description of the Related Art In recent years, technology development of electric vehicles that run using electricity has been rapidly developed. An electric vehicle includes a motor for generating rotational force, a battery for providing power to the motor, an inverter for controlling the rotation speed of the motor, a charger for storing electricity in the battery, and a low DC converter for generating 12V power for a vehicle.

Characteristics of these parts are to change the form of electrical energy to suit the purpose, from AC power to DC, from low-voltage DC to high-voltage DC, or vice versa, from high-voltage DC to low-voltage DC.

A voltage ripple generated in this process may adversely affect surrounding electrical elements, and to attenuate it, a DC-link capacitor is used, and a film capacitor is widely used as a DC-link capacitor.

This film capacitor is a general application technology not only in industry but also in inverter systems. In inverters that control drive motors of electric vehicles, to absorb high-frequency ripple current by smoothing and switching to remove voltage pulsation components at the DC input voltage stage. Place the film capacitor close to the switch of the inverter and use it for the DC input terminal.

However, the high-frequency ripple current causes the film capacitor to generate heat during use, which increases the internal temperature of the film capacitor together with the applied voltage, shortening the lifespan, and eventually lowering the performance of the entire inverter system.

To improve this, the conventional film capacitor has a cooling structure as shown in FIG. 1 .

Specifically, one film capacitor cell module 126 is configured by configuring a set of two film capacitor unit cells 124 arranged vertically. At this time, two unit cells 124 of one film capacitor cell module 126 are installed by connecting (+) and (-) pole bus bars 125 to both ends of the upper and lower film capacitor unit cells 124 . ) are assembled together.

After assembling the film capacitor cell module 126 composed of two unit cells 124 as described above, a plurality of them are combined to form the required capacity of the film capacitor. A required number of film capacitor cell modules 126 are accommodated in each storage space 123 . Here, the case 121 is made of a metal material such as aluminum having good thermal conductivity and good heat dissipation performance, and a plurality of partition walls 122 dividing the inner space into a plurality of storage spaces 123 are integrated at regular intervals. It is provided in a formed structure.

The film capacitor cell module 126 assembled by the bus bar 125 is accommodated in each storage space 123 partitioned by the partition wall 122 in the inner space of the case 121 having the above structure, and then the case ( The cell module 126 is epoxy-molded in the inner space of the case 121 by injecting an epoxy resin between the cell modules 126 accommodated in each storage space 123 of the 121) and then curing. Through the epoxy molding, each film capacitor unit cell 124 can be insulated and fixed in the inner space of the case 121 .

Thereafter, the (+) pole bus plate 127A and the (-) pole bus plate 127B are welded or soldered (soldered) to the upper surface of the case 121 so as to cover the upper surface of the inner space of the case 121 and assembled At this time, the insulating paper 128 is inserted between the two bus plates 127A and 127B, so that the two bus plates 127A and 127B are insulated from each other.

Each of the bus plates 127A and 127B is a conductive plate made of a copper alloy, and the bus bar 125 of the same pole and the bus plates 127A, 127B are connected to each other, and each bus plate is different from the bus bar 125 of the other pole. It is insulated with an insulating material (not shown) interposed therebetween.

When the bus plates 127A and 127B are covered on the upper surface of the case 121 as described above, the assembly of the film capacitor module 120 is completed.

The above conventional film capacitor is inserted between the film capacitor cell modules 126 through the internal space of the partition wall 122 of the case 121 in order to transfer the generated heat to the heat sink (not shown) through the case 121 to be discharged. Through a cooling structure in which the cooling fins (not shown) of the heat sink receive the heat of the film capacitor cell module directly from the inside and discharge it to the outside, it is possible to extend the life of the capacitor and secure the stable performance of the inverter while having better cooling performance. .

However, since the structure of the conventional film capacitor forms the partition wall 122 in the inner space of the case 121 made of a metal material for thermal conductivity, the overall weight and volume are increased.

Accordingly, it is an object of the present invention to provide a film capacitor module capable of improving cooling performance without a metal case and a barrier rib structure for thermal conductivity in order to reduce overall weight and volume.

In order to achieve the above object, the film capacitor module of the vehicle inverter is a film capacitor module used as a DC-link capacitor in the vehicle inverter. A plurality of film capacitor unit cells having an N-pole electrode formed thereon, a P-pole bus bar coupled to the P-pole electrode formed on one end surface of the plurality of film capacitor unit cells, and a P-pole bus bar formed on the other end surface of the plurality of film capacitor unit cells an N-pole bus bar coupled to the N-pole electrode, an upper heat sink formed on the P-pole bus bar, and a lower heat sink formed on the N-pole bus bar.

According to the present invention, since the bus bar is fixed to the upper and lower portions of the film capacitor unit cell in a structure that is fastened, a metal case and epoxy filling for thermal conductivity are unnecessary, so manufacturing cost and total weight And by reducing the volume and simplifying the assembly process, it is possible to significantly improve product productivity.

1 is a view for explaining the structure and manufacturing process of a conventional film capacitor module.
2 is a perspective view three-dimensionally showing a structure of a film capacitor module of an inverter for a vehicle according to an embodiment of the present invention.
3 is a cross-sectional view taken along the cutting line A-A' shown in FIG. 2 .

As described above, in the conventional film capacitor module, partition walls are formed in the internal space, film capacitor unit cells are accommodated in each storage space of the case separated by the partition walls, and the unit cells accommodated in each storage space are fixed. Epoxy was molded to insulate, but this structure has disadvantages in that the weight and volume increase due to the barrier rib structure formed in the inner space of the case.

Therefore, in order to reduce the volume and weight of the capacitor, we propose a double-sided cooling capacitor module that can improve cooling performance without designing a case and a bulkhead structure made of thermally conductive metal.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a perspective view three-dimensionally showing the structure of a film capacitor module of an inverter for a vehicle according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along the cutting line A-A' shown in FIG. 2 .

2 and 3 , the film capacitor module of the vehicle inverter according to an embodiment of the present invention includes a plurality of film capacitor unit cells 110 , a P-pole bus bar 120 , an N-pole bus bar 130 , It includes an insulating paper 140 and a heat sink 150 (heat sink).

Each of the plurality of film capacitor unit cells 110 may be configured by winding a pair of metallized films to form electrodes on both end surfaces thereof.

The metallized film is formed by providing a metal deposition electrode on one or both surfaces of a dielectric film made of polypropylene. In addition, the metal deposition electrode may be configured to be wound in a state opposite to the dielectric film therebetween.

The electrodes formed on both end surfaces may be configured as a pair of extracted electrodes of a P-pole electrode and an N-pole electrode.

In this embodiment, a total of eight film capacitor unit cells 110 are configured in a set of two each to constitute one film capacitor module, and thus, four film capacitor modules are exemplified. Of course, the present invention is not limited to the structure consisting of a total of eight film capacitor unit cells 110, and various modifications may be made.

A total of eight film capacitor unit cells 110 are interposed therebetween, and the P-pole bus bar 120 is electrically coupled to the upper side of each unit cell 110 , and the N-pole bus bar is electrically coupled to the lower side of each unit cell 110 . 130 is fastened.

The P-pole bus bar 120 has a plate shape and may be a conductor made of a copper alloy material, and a P-pole terminal part 120A for external connection is formed at one end of the P-pole bus bar 120 . In a state in which the eight film capacitor unit cells 110 are closely arranged, the P-pole bus bars 120 are electrically coupled to the P-pole electrodes formed on one end surface of each unit cell 110 , respectively.

The N-pole bus bar 130 also has a plate shape and may be a conductor made of a copper alloy material, and an N-pole terminal portion 130A for external connection is formed at one end of the N-pole bus bar 130 . In a state in which the eight unit cells 110 are arranged in close contact, the N-pole bus bar 120 is electrically coupled to the N-pole electrode formed on one end surface of each unit cell 110 , respectively.

In this way, with the eight film capacitor unit cells 110 interposed therebetween, the upper and lower sides of each unit cell 110 are electrically coupled to each other by the P-pole bus bar 120 and the N-pole bus bar 130 , respectively. Eight film capacitor unit cells 110 may be connected in parallel.

Since the structure as described above is fixed in a structure in which the P-pole bus bar and the N-pole bus bar are electrically fastened to the upper and lower surfaces of the film capacitor unit cell, respectively, as in a separate plastic or conventional case, a metal case or the inner space of the case It is possible to omit the epoxy filling process in which the epoxy needs to be filled.

On the other hand, in the above structure, since the film capacitor unit cell 110 is exposed to the outside and is vulnerable to ambient temperature or heat generation, in an embodiment of the present invention, the P-pole bus bar 120 and the N-pole bus bar By fastening each heat sink on 130 , heat generated in the film capacitor unit cell 110 can be easily dissipated to the outside.

Specifically, an upper heat sink 150-1 is formed on the P-pole bus bar 120 with an upper insulating paper 140-1 interposed therebetween, and a lower insulating paper 140- is formed on the N-pole bus bar 130. 2), the lower heat sink 150-2 is formed. That is, the P-pole bus bar 120 and the N-pole bus bar 130 dissipate heat generated in a plurality of film capacitor unit cells to the upper heat sink 150-1 and the lower heat sink 150-2, respectively. It plays a role in transferring

By doing this, the heat generated in the film capacitor unit cell 110 can be easily discharged to the outside, and the heat is directly transferred from the P-pole bus bar 120 and the N-pole bus bar 130 (actually, insulating paper). It is transmitted to the outside), so it can have better cooling performance.

As described above, in the film capacitor module of the vehicle inverter, the plate-shaped bus bars 120 and 130 are directly connected to the heat sink without a separate metal case capable of dissipating heat to the outside, and the coolant flowing through the flow passage. It is possible to maximize the cooling performance by rapidly dissipating heat through the

Accordingly, it is possible to effectively suppress the temperature rise of the film capacitor due to the high-frequency ripple current of the inverter by maximizing the cooling performance of the film capacitor module, thereby extending the life of the film capacitor module and securing stable performance of the inverter.

In addition, it is possible to reduce the volume and weight with a structure that does not require epoxy filling and a separate case, and it is possible to reduce the size of the film capacitor unit cell by improving heat dissipation performance.

As described above, in the film capacitor module of the present invention, the configuration and method of the described embodiments are not limitedly applicable, but all or part of each embodiment is selective so that various modifications can be made to the embodiments. It may be configured in combination with .

Claims (5)

In the film capacitor module used as a DC-link capacitor in a vehicle inverter,
In the form in which a pair of metallized films are wound, a plurality of film capacitor unit cells having a P-pole electrode and an N-pole electrode formed on both end surfaces;
a plate-shaped P-pole bus bar coupled to the P-pole electrode formed on one end surface of the plurality of film capacitor unit cells;
a plate-shaped upper insulating paper covering the upper front surface of the P-pole bus bar;
a plate-shaped N-pole bus bar coupled to the N-pole electrode formed on the other end surface of the plurality of film capacitor unit cells;
a plate-shaped lower insulating paper covering the upper front surface of the N-pole bus bar;
an upper heat sink covering the upper front surface of the upper insulating paper; and
Including; a lower heat sink covering the upper front surface of the lower insulating paper;
The plurality of film capacitor unit cells,
As a structure in which the side surface is exposed to the outside,
The film capacitor module having a structure in which the upper insulating paper, the upper heat sink, the lower insulating paper, and the lower heat sink are formed on upper and lower portions to expose the side surface to the outside.
delete According to claim 1, wherein each of the P-pole bus bar and the N-pole bus bar,
A film capacitor module, characterized in that it serves to transfer heat generated in the plurality of film capacitor unit cells to the upper heat sink and the lower heat sink, respectively.
delete According to claim 1, At one end of the P-pole bus bar,
A P-pole terminal part for external connection is formed,
At one end of the N-pole bus bar,
Film capacitor module, characterized in that the N-pole terminal for external connection is formed.

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