WO2013088546A1

WO2013088546A1 - Capacitor device and electrical equipment for housing capacitor device

Info

Publication number: WO2013088546A1
Application number: PCT/JP2011/078994
Authority: WO
Inventors: 勇一郎吉武; 越智　健太郎; 井上　重徳; 加藤　修治
Original assignee: 株式会社日立製作所
Priority date: 2011-12-15
Filing date: 2011-12-15
Publication date: 2013-06-20
Also published as: JP5941064B2; JPWO2013088546A1

Abstract

The objective of the present invention is to provide a capacitor device capable of integrating, with high density, ceramic capacitors on a capacitor requiring large capacity, and to provide an electrical device for housing the capacitor device. The objective is also to achieve a high-density mount that includes a protective function. This purpose is achieved by configuring the capacitor device such that cube-shaped capacitors having external electrodes provided to pairs of mutually facing surfaces are arranged vertically and horizontally to form a capacitor unit so that the mutually facing surfaces are aligned with each other, a plurality of such capacitor units are configured in layers so that shared electrodes are disposed between the facing surfaces, and adjacent shared electrodes that are separated from each other by one shared electrode are connected to one external terminal.

Description

Capacitor device and electric device for storing capacitor device

The present invention relates to a capacitor device and an electric device (a power conversion panel, a power conversion unit, and a power conversion unit) that store the capacitor device, and more particularly to a capacitor device that enables high-density mounting and an electric device that stores the capacitor device.

In electrical equipment, capacitors are applied to rapidly supply electrical energy to the electrical circuit. Capacitors are used in a wide variety of electrical equipment such as inverters, circuit breakers, transformers, and high-voltage power supplies. There are various types of capacitors depending on the internal structure. In addition, the specifications of capacitors differ depending on the voltage class and application.

For example, in a high voltage inverter, a smoothing capacitor is arranged inside the inverter panel or inside the unit cell. As the smoothing capacitor, an aluminum electrolytic capacitor or a film capacitor is used according to the voltage class. In addition, as another application, a snubber capacitor may be disposed to reduce the jumping voltage.

The above-mentioned smoothing capacitor occupies a large volume ratio in the inverter. The capacitor volume is proportional to the square of the electric field applied to the dielectric between the electrodes. In an inverter whose rated voltage exceeds 500V, a film capacitor is mainly used because of its high insulating property, but its relative dielectric constant is 2 to 10.

As described above, generally, when the voltage is increased, the volume ratio is inevitably increased. As the voltage is increased, the capacitor size becomes a major obstacle to downsizing the inverter.

On the other hand, ceramic capacitors have a very high dielectric constant, and are used for personal computers and portable terminal devices with low voltage. In recent years, ceramic materials and capacitor structures for inverters in the high voltage region have been developed, and there is a tendency to reduce the inverter volume.

In this regard, in Patent Document 1, a ceramic capacitor is used as the capacitor of the power converter. The ceramic capacitor is protected by a protective device such as a fuse.

JP 2006-230156 A

As described above, there are attempts to apply ceramic capacitors to power equipment, but there are many problems to be solved in actual application.

Ceramic capacitors are limited in size per capacitor from the point of manufacturing process. Considering the DC bias voltage, the capacity of one capacitor when the rated voltage is applied is considered to be about 10 μF. Since the capacitor applied to the high-voltage inverter has a large capacity and exceeds 1 mF, when a ceramic capacitor is applied, it is necessary to connect in large quantities in parallel.

Also, since ceramic capacitors fail in the short-circuit mode, a short-circuit protection function that can isolate the failure location when mounted in large quantities is indispensable. In the technology of the above-mentioned patent document, a protective function is required for each capacitor, but the volume of the fuse itself is large. In addition, an insulation distance between the ceramic capacitors is required, resulting in an insulation space.

For this reason, when applying a plurality of ceramic capacitors to a large-capacity capacitor, a mounting technique for mounting individual capacitors at a high density is required. Furthermore, it is desirable that the high-density mounting in this case is a mounting technology including a fuse that performs a capacitor protection function.

In view of the above, an object of the present invention is to provide a capacitor device capable of integrating ceramic capacitors at a high density in a capacitor that requires a large capacity, and an electric device that houses the capacitor device. Furthermore, in this high-density mounting, high-density mounting including a protection function is realized.

The above-described problem is that a cube-shaped capacitor having external electrodes on a pair of opposed surfaces is arranged in a vertical and horizontal manner with the opposing surfaces aligned to form a capacitor unit, and the opposing surfaces of a plurality of capacitor units This is achieved by arranging the capacitor electrode so as to connect the common electrode adjacent to one of the shared electrodes to one external terminal.

According to the present invention, the conventional smoothing capacitor can be miniaturized by the three-dimensional paralleling of ceramic capacitors, and the electrical equipment can be miniaturized.

The figure which shows the specific structural example of the capacitor | condenser mounted in an inverter unit. The figure which shows sectional drawing of a typical inverter unit. The figure which shows an example of the external appearance of the unit capacitor comprised by the cube shape. The figure which showed functionally the arrangement relation of the external electrode and internal electrode in a unit capacitor. The figure which shows the connection relation of the structure of a shared electrode, and a capacitor | condenser unit. The figure which shows the structural example which gives a fuse function using an internal electrode. The figure which shows the structure which clamps a capacitor group between bus bars. The figure which shows the capacitor | condenser structure for implement | achieving FIG. The figure which shows the capacitive shared electrode which gave the capacity | capacitance to the shared electrode. The figure shown about the structure which lost the shared electrode containing a protective function.

Hereinafter, the capacitor device of the present invention will be described with reference to the drawings.

Fig. 2 shows a cross-sectional view of an inverter unit as a typical example of electrical equipment. The structure inside the unit will be described with reference to FIG. Inside the inverter unit 30 are an IGBT 1 that is a semiconductor switching element, a cooling fin 2 that is mounted on the IGBT 1 and dissipates heat generated by the IGBT 1, and an air filter 4 that removes dust and the like from the air sucked into the unit 30. In addition, parts such as the bus bar 5 and the capacitor 3 are accommodated. The bus bar 5 electrically connects the positive electrode and the negative electrode of the IGBT 1 and the capacitor 3.

Thus, it can be said that the electric device is constituted by a casing as an outer frame, main body devices (IGBT 1, cooling fins 2, air filter 4), and a capacitor device (bus bar 5, capacitor 3).

In the inverter unit 30 in FIG. 2, a plurality of parts are accommodated in a limited housing volume, and therefore the capacitor 3 used here needs to have a predetermined capacity with a limited volume. For example, in the inverter unit 30 of FIG. 2, the IGBT 1 and the cooling fin 2 occupy the space A on the right half, so it is necessary to arrange the capacitor 3 using the space B on the left half effectively.

Usually, since the inverter unit 30 which is a casing is a cube, the space B permitted for mounting the capacitor 3 is also often a cube. However, the capacity of the capacitor mountable space B varies depending on the capacity of the inverter unit 30. Accordingly, in the present invention, when the capacitor 3 is formed into a cube having a shape matching the capacitor mounting space B, the small-capacity unit capacitor 31 is formed in a cube, and this is three-dimensionally arranged in the vertical, horizontal, and height directions. Stack up to form a capacitor group. The unit capacitor 31 is a ceramic capacitor.

FIG. 3 shows an example of the appearance of the unit capacitor 31 configured in a cubic shape. On the left and right surfaces of the cube forming the unit capacitor 31, the first and second

external electrodes

32 and 33 are arranged to face each other. A plurality of first and second

internal electrodes

34 and 35 extend from the first and second

external electrodes

32 and 33 respectively in the lateral direction. Each of the first and second

external electrodes

32 and 33 and the first and second

internal electrodes

34 and 35 has a plate shape, for example, and a cubic portion other than the electrodes is filled with a high dielectric material 36. ing.

Here, as a characteristic configuration of the present invention, the first and second

external electrodes

32 and 33 are not disposed in the entire left and right regions, but are disposed in a partial region. The hatched lines indicate the first and second

external electrodes

32 and 33, and other portions on the left and right surfaces are made of an insulating high dielectric material 36. In addition, as for the

internal electrodes

34 and 35 extending in the lateral direction, only one of them is taken out as shown as 35, and the side a in contact with the

external electrodes

32 and 33 is a narrow region, and the internal region b The shape is such that a large area can be secured.

FIG. 4 functionally shows the positional relationship between the first and second

external electrodes

32 and 33 and the first and second

internal electrodes

34 and 35 by removing the high dielectric material 36 of the cubic unit capacitor 31. It is a figure. The reason why it is functionally explained is that the unit capacitor 31 is actually stacked to manufacture the unit capacitor 31, and therefore does not actually exist in the form of FIG.

Although it is only functionally, first and second

external electrodes

32 and 33 are arranged to face each other on a part of the left and right surfaces of the unit capacitor 31, and for example, three each from each of the

external electrodes

32 and 33. The plate-like

internal electrodes

34 and 35 extend in the lateral direction. Each of the three plate-like

internal electrodes

34 and 35 are opposed to each other so as to be sandwiched alternately. In the example shown in the figure, the capacitor function is obtained by arranging the

layers

35a, 34a, 35b, 34b, 35c, and 34c from the top.

3 and 4 are already well-known in the literature. In the present invention, a capacitor obtained by adding the above-described characteristic configuration to the known capacitor 31 is used as a unit capacitor, and stacked in the vertical, horizontal, and height directions.

FIG. 1 shows an example in which a ceramic capacitor group is used as a specific structural example of the capacitor 3 mounted on the inverter unit 30. Here, the single ceramic capacitor 31 is electrically connected in parallel in the vertical, horizontal, and height directions.

More specifically, the capacitor 3U in FIG. 1 includes four unit capacitors 31 in the direction of FIG. 3 arranged in the X direction and stacked in four stages in the height direction Z, and the capacitor units (31A, 31B). , 31C, 31D), and capacitor units (31A, 31B, 31C, 31D) are assembled in four rows in the Y direction. Accordingly, the right side surface of the capacitor unit 31A is, for example, the second external electrode 32, and the left side surface that is hidden in the drawing is, for example, the first external electrode 33. This stacked arrangement is performed in the same way for the

other capacitor units

31B, 31C, and 31D. However, in the

capacitor units

31B and 31D, the right side surface is the first external electrode 33 and the left side surface is the second external electrode 32. It arrange | positions so that it may become.

Further, a shared electrode 37 is disposed between the

capacitor units

31A, 31B, 31C, and 31D. As a result, two sets of adjacent capacitor units connect the same

external electrode

32 or 33 through the shared electrode 37. In the illustrated example, the shared electrodes 37AB and 37CD are the first shared electrodes 37 that are connected to the first external power supply of two adjacent sets of capacitor units, and the shared electrodes 37BC are the two sets of adjacent capacitor units. A second shared electrode connected to a second external power source. Needless to say, the right side surface of the finally assembled capacitor 3 has the same potential as the second shared electrode, and the left side surface of the finally assembled capacitor 3 has the same potential as the first shared electrode. .

FIG. 5 is a diagram showing the connection relationship between the structure of the shared electrode and the capacitor unit. Here, the correspondence relationship of 37BC as the shared electrode and 31B as the capacitor unit will be described as an example. The shared electrode 37BC is in contact with the capacitor unit 31A on the back surface, so that the back surface has the same structure as the front surface.

First, the capacitor unit 31B will be described. In this unit, 16 unit capacitors 31 are stacked vertically and horizontally. Further, external electrodes are arranged on the left and right surfaces of the unit capacitor 31, but the external electrodes are provided not in the entire area of the left and right surfaces but in a partial region. In the drawing, the external electrode 33 appears on the visible side. Further, regarding the four unit capacitor rows (31BZ1) in the height direction of the capacitor unit 31B, the external electrodes 3 are arranged so as to come to the same position in the height direction (left side in the height direction in the drawing). This relationship is also maintained for four unit capacitor rows (for example, 31BZ2) in other height directions.

On the other hand, the shared electrode 37BC is actually composed of four unit shared electrodes (37BC1, 37BC2, 37BC3, 37BC4) in the height direction in a capacitor unit in which 16 unit capacitors 31 are stacked vertically and horizontally. . Accordingly, the unit shared electrode 37BC1 is disposed at a position facing the unit capacitor array 31BZ1, and the unit shared electrode 37BC2 is disposed at a position facing the unit capacitor array 31BZ2. Since all the unit shared electrodes 37BC have the same configuration, the unit shared electrode 37BC1 will be described as an example here.

The unit shared electrode 37BC1 is formed by evaporating two rows of

electrodes

22 and 23 on the non-deposited film 25 in the height direction. Thereby, the insulation distance between the base material 29 of the unit shared electrode and the

electrodes

22 and 23 and between the

electrodes

22 and 23 is secured. Among these, the vapor deposition electrode 22 is in contact with the external electrodes 33 of the four unit capacitor rows 31BZ1 in the height direction of the capacitor unit 31B and is connected. The other vapor deposition electrode 23 comes into contact with a portion of the insulating high dielectric material 36 in the height direction of the capacitor unit 31B, and there is no electrical connection between them.

In the unit shared electrode 37BC1, narrow conductive portions 24 are provided between the

vapor deposition electrodes

22 and 23 in two rows in the height direction. Further, one or more conducting portions 24 are provided per unit capacitor, preferably the same number. This conduction part 24 fulfills the function of a fuse provided between the

vapor deposition electrodes

22, 23, and fulfills the function of fusing with the overcurrent of the unit capacitor 31 to protect the capacitor.

In the unit shared electrode 37BC1, the

vapor deposition electrodes

22 and 23 in two rows in the height direction are extended to the upper end of the unit shared electrode 37BC1, but the other is not extended to the upper end. Adjacent unit sharing electrodes are vapor deposition electrodes having the same length. For example, the vapor deposition electrodes extending to the upper end are in contact between the unit shared electrode 37BC1 and the adjacent 37BC2, and the vapor deposition electrodes not extending to the upper end are in contact between the unit shared electrode 37BC2 and the adjacent 37BC3. The

It should be noted that the vapor deposition electrodes extending to the upper end of the unit shared electrode 37BC1 can be externally connected together with the vapor deposition electrode extending to the upper end on this back surface to constitute an external connection terminal. In the example of FIG. 1, the common electrode 37AB and the common electrode 37CD are commonly connected to form a first external connection terminal, and the common electrode 37BC is a second external connection terminal, whereby the capacitor 3 of FIG. In FIG. 2, the shared electrodes 37 are connected by the bus bar 5, and the external connection is made by the bus bar 5 with the IGBT.

1 is combined so that the unit capacitor 31 and the unit shared electrode 37 are in the above positional relationship. As a result, by selecting the number of combinations in the vertical and horizontal height directions, it is possible to obtain the capacitor 3 having a shape and volume corresponding to the storage location in the housing.

As described above, in FIG. 1, capacitors are stacked in the height direction (z direction), the external electrodes of adjacent capacitors are the same, and the potential is the same, so there is no need to secure an insulating space between the capacitors. . In a high-voltage capacitor, the insulation distance increases as the voltage increases. Therefore, it is very effective to eliminate the insulation distance.

Also in FIG. 1, the insulation distance can be eliminated by making the polarities of the external electrodes of adjacent capacitors adjacent in the horizontal direction (y direction) the same. Here, in the first embodiment, the shared electrode 37 is provided between the horizontal capacitors. There is also an example in which the shared electrode 37 is not used as shown in Example 4 described later.

In the structure of the ceramic capacitor unit 31 in FIG. 3, the external electrodes are assumed to be partial on the surfaces of the

external electrodes

32 and 33 that are in contact with the shared electrode 37. In the conventional ceramic capacitor 31, the

external electrodes

32 and 33 are mainly provided on the entire outer surface of the ceramic dielectric 36.

Further, as the metal of the

external electrodes

32 and 33 of the ceramic capacitor unit 31, silver, copper, aluminum, nickel, and alloys thereof can be considered, but any metal can be used as long as it is a conductive metal. no problem. As an electrode forming method, a method such as paste, vapor deposition, sputtering, or plating is applied. In this embodiment, the

external electrodes

32 and 33 are mainly formed of copper paste.

Similarly, silver, copper, aluminum, nickel and alloys thereof may be used for the internal electrode of the ceramic capacitor, but any metal can be used as long as it is a conductive metal. In Example 1, a nickel alloy is mainly used.

Further, the characteristics required for the material applied to the high dielectric material 36 filled between the electrodes of the single capacitor 31 are a relative dielectric constant of 500 or more after firing and a distance between electrodes of 0.05 to 0.5 mm. . For this required characteristic, BaTiO3 series, ZeO-added SiC, SrTiO3 series, ZeO-added SiC, and the like are conceivable.

As the shared electrode 37 in FIG. 5, metal is partially applied to the surface of a non-metallic substance. As the nonmetallic material, an epoxy resin, a film, a ceramic, or the like is applied. The surface metal is composed of zinc, silver, copper, aluminum, nickel, and alloys thereof using means such as paste, vapor deposition, sputtering, and plating.

In this embodiment, a metal is deposited on the film. As the material of the film, polypropylene, polyethylene, polyethylene terephthalate, polyvinylidene fluoride, polyvinylidene chloride, polyethyl ether ketone, polyether imide, or the like is used, but any film can be used. The vapor deposition metal may be an alloy of zinc and aluminum, or each may be used alone.

For the surface electrode of the shared electrode 37, a narrow portion is provided in the electrode. In this embodiment, the electrode is divided into two

islands

22 and 23, and a thin electrode 24 is used as a bridge. The partial

external electrodes

32 and 33 of the ceramic capacitor 31 described above are brought into contact with this one surface. The other is electrically connected to the electrode to the upper bus bar 5.

By providing the narrow portion 24 in the electrode, when an accident or failure occurs on the ceramic capacitor 31 side and a short circuit occurs, an overcurrent flows through the capacitor. The overcurrent generates heat due to high electrical resistance in the narrow portion 24 and melts.

Narrow part 24 is a fuse. The length of the width with respect to the direction in which the current flows determines the electrical resistance of the fuse portion, that is, the short circuit current. The length of the fuse is determined by the creeping insulation distance necessary for the voltage applied between the electrode on the ceramic capacitor connection side and the electrode on the bus bar side.

As described above, it becomes possible to electrically separate the ceramic capacitors in which an abnormality has occurred individually, and it is possible to prevent short-circuiting the entire ceramic capacitor group in which a large number of capacitors are connected in parallel.

FIG. 6 shows Example 2. In the first embodiment, the shared electrode 37 is used to provide a fuse function, but the

internal electrodes

34 and 35 are used here. For example, the internal region b of the internal electrode 35 is divided into two to form internal regions b1 and b2. In addition, a narrow portion 24 is formed between the internal regions b1 and b2. The internal regions b1 and b2 are divided into a side a that contacts the external electrode and a side that does not contact the external electrode. This division position is appropriately determined according to the capacitor capacity and the like.

The narrow portion 24 makes it possible to electrically separate the ceramic capacitors in which an abnormality has occurred, and to prevent the entire ceramic capacitor group having a large number of capacitors connected in parallel from being short-circuited.

In this case, the fuse function using the shared electrode 37 can be used as it is, or the shared electrode 37 can be prevented from having a fuse function. In the latter case, the two

vapor deposition electrodes

22 and 23 may be integrated.

FIG. 7 shows Example 3. In this embodiment, the ceramic capacitor group 3 is sandwiched between the bus bars 5. With this structure, the capacitor 3 is applied to the insulating space between the bus bars, which has been a dead space, and the space in the inverter 30 can be used effectively, contributing to the downsizing of the inverter.

Fig. 8 shows the structure of a ceramic capacitor group for realizing this structure. As shown in the figure, electrodes connected to the bus bar 5 are arranged vertically. That is, the shared electrodes 37AB and 37CD are taken out from the upper part of the capacitor unit 3U, but the shared electrode 37BC is taken out from the lower part of the capacitor unit 3U, so that a ceramic capacitor group can be arranged in the space between the bus bars 5. become.

Furthermore, in Example 3, a capacitive shared electrode 370 in which the shared electrode 37 has a capacity is shown in FIG. In the embodiment shown in FIG. 1, the capacitance is secured in the ceramic capacitor portion. In this embodiment, the capacitance is secured also in the shared electrode portion in addition to this, so that the capacity can be increased. For the base material 29 of the shared electrode 37 in FIG. 5, the

electrodes

22 and 23 are formed on one or both surfaces of the surface of the film 25 as in the first embodiment. Capacitance can be obtained by alternately stacking the polarities of the

electrodes

22 and 23.

In FIG. 7, electrodes connected to the bus bar connected to the IGBT are provided on the upper and lower portions. As a method for applying the electrode, a technique such as plating, metallicon, or vapor deposition may be used. In the present embodiment, the eyes are applied. As a result, it is possible to connect the upper and lower electrodes to the positive and negative bus bars 5, respectively.

FIG. 10 shows a structure in which the shared electrode 37 including the protection function is eliminated. In this case, the electrode 38 is not provided with the

vapor deposition electrodes

22 and 23 in two rows in the height direction in FIG. 6 and the narrow conductive portion 24 therebetween. One side is covered with one vapor deposition electrode. As a protective function, the method of the second embodiment in which the internal electrode is provided may be used.

Alternatively, this structure can be adopted if the design tolerance of each ceramic capacitor is large and the structure does not cause failure of each capacitor. In order to increase the design margin of individual ceramic capacitors, the distance between the internal electrodes should be kept large.

DESCRIPTION OF SYMBOLS 1: IGBT which is a semiconductor switching element, 2: Cooling fin, 3: Capacitor, 4: Air filter 4, 5: Bus bar, 22, 23: Electrode, 24; Narrow part, 25: Non-deposition film, 29: Unit shared electrode 30: inverter unit, 31: unit capacitor, 31A, 31B, 31C, 31D: capacitor unit, 32, 33: first and second external electrodes, 33, 34: first and second internal electrodes 36: high dielectric material, 37: shared electrode, 37BC1, 37BC2, 37BC3, 37BC4: unit shared electrode, 370: capacitive shared electrode, A: space occupied by IGBT1 and cooling fin 2, B: space where capacitor can be mounted , B1, b2: inner area

Claims

Cubic capacitors having external electrodes on a pair of opposing surfaces are arranged vertically and horizontally with the opposing surfaces aligned to form a capacitor unit, and a plurality of capacitor units are shared between the opposing surfaces. The capacitor device is configured by arranging and laminating one of the shared electrodes, and connecting one adjacent shared electrode to one external terminal.
The capacitor device according to claim 1,
The cubic capacitor is a capacitor device characterized in that it is a ceramic capacitor configured by alternately laminating internal electrodes electrically connected to two external electrodes.
The capacitor device according to claim 1 or 2,
The external electrodes of the pair of opposing surfaces of the capacitor are formed on a part of the surface, the shared electrode is a first electrode that contacts the external electrodes of the plurality of capacitors, and the external of the capacitors A second electrode that does not contact the electrode; and a narrow portion that is formed on an insulating member between the first electrode and the second electrode and connects the first electrode and the second electrode. Capacitor device.
The capacitor device according to claim 2,
The internal electrode of the capacitor includes a first internal electrode portion connected to the external electrode, a second internal electrode portion not connected to the external electrode, and between the first internal electrode portion and the second internal electrode portion. A capacitor device comprising a first internal electrode portion and a narrow portion connecting the second internal electrode portion formed on the insulating member.
The capacitor device according to claim 2,
A capacitor device characterized in that the distance between the alternately stacked internal electrodes is sufficient to maintain insulation.
The capacitor device according to any one of claims 1 to 5,
The shared electrode has a capacitance by forming electrodes on one or both surfaces of a film surface and alternately laminating the polarities of the electrodes.
In the housing as the outer frame, in the electrical equipment that houses the main unit and the capacitor device,
The capacitor device is:
Cubic capacitors having external electrodes on a pair of opposing faces are arranged vertically and horizontally with the opposing faces aligned to form a capacitor unit, and a plurality of capacitor units are shared between the opposing faces. Are arranged by laminating and connecting one shared electrode adjacent to one of the shared electrodes to one external terminal,
An electrical device that houses a capacitor device, wherein the electrical device is connected to the main device via the external terminal.
In the electric equipment which houses the capacitor device according to claim 7,
An external device is connected to a bus bar provided between the main device and the capacitor device.
In the electric equipment which stores the capacitor device according to claim 8,
One of the two external terminals of the capacitor device is taken out from one surface of the cubic capacitor device, and the other of the two external terminals is taken out from a surface facing the one surface of the cubic capacitor device, An electric device for storing a capacitor device, wherein each capacitor device is stored in a space region formed by the bus bar by being connected to the bus bar.