JP2021057970A - Capacitor cooling structure - Google Patents

Abstract

To satisfactorily improve the heat dissipation effect of a capacitor element using a positive electrode bus bar and a negative electrode bus bar with respect to a capacitor cooling structure.SOLUTION: A capacitor cooling structure according to the present invention includes a capacitor, a positive electrode bus bar, a negative electrode bus bar, and a cooler. The capacitor includes a capacitor element, and has a positive electrode surface and a negative electrode surface, and a plurality of non-electrode surfaces which are outer surfaces other than the positive electrode surface and the negative electrode surface as outer surfaces. The positive electrode bus bar is in contact with the positive electrode surface. The negative electrode bus bar is in contact with the negative electrode surface. The cooler directly or indirectly cools the positive electrode bus bar and the negative electrode bus bar. Each of the plurality of non-electrode surfaces is in contact with at least one of the positive electrode bus bar and the negative electrode bus bar.SELECTED DRAWING: Figure 1

Description

The present invention relates to a condenser cooling structure.

For example, Patent Document 1 discloses a heat dissipation structure of a capacitor. In the heat dissipation structure of this capacitor, the capacitor electrode plate protruding from the capacitor body is connected to an external device provided with a heat dissipation portion. In addition, the intermediate portion of the capacitor electrode plate located between the capacitor body and the external device is in direct or indirect contact with the heat radiating portion. With such a heat radiating structure, the heat of the capacitor electrode plate is released to the heat radiating portion.

Japanese Unexamined Patent Publication No. 2007-123572

In the heat dissipation structure described in Patent Document 1, the capacitor electrode plates (positive electrode bus bar and negative electrode bus bar) are connected to the electrodes of the capacitor body so as to secure the energizing function. Therefore, the area of the portion where the two are in contact is limited. Therefore, according to this heat dissipation structure, it is considered difficult to sufficiently enhance the heat dissipation effect of the capacitor body (the capacitor element inside the capacitor element) by using the capacitor electrode plate.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a capacitor cooling structure capable of satisfactorily improving the heat dissipation effect of a capacitor element using a positive electrode bus bar and a negative electrode bus bar. ..

The condenser cooling structure according to the present invention includes a condenser, a positive electrode bus bar, a negative electrode bus bar, and a cooler. The capacitor includes a capacitor element, and has a positive electrode surface and a negative electrode surface, and a plurality of non-electrode surfaces which are outer surfaces other than the positive electrode surface and the negative electrode surface as outer surfaces. The positive electrode bus bar is in contact with the positive electrode surface. The negative electrode bus bar is in contact with the negative electrode surface. The cooler directly or indirectly cools the positive electrode bus bar and the negative electrode bus bar. Each of the plurality of non-electrode surfaces is in contact with at least one of the positive electrode bus bar and the negative electrode bus bar.

According to the capacitor structure according to the present invention, each of the plurality of non-electrode surfaces, which is the outer surface of the capacitor other than the electrode surface, is in contact with at least one of the positive electrode bus bar and the negative electrode bus bar. As a result, the heat transfer area between the capacitor and the positive electrode bus bar and the negative electrode bus bar can be increased, so that the heat dissipation effect of the capacitor element using the positive electrode bus bar and the negative electrode bus bar can be satisfactorily improved.

It is a perspective view which showed the capacitor which concerns on embodiment and the structure around it. It is a perspective view which shows the appearance of the capacitor module including the capacitor shown in FIG. It is a figure for demonstrating the structure inside and around the capacitor case shown in FIG. It is a perspective view for demonstrating the capacitor module which has only the energization function which concerns on a comparative example. It is a figure which showed the temperature distribution inside the capacitor module (comparative example) shown in FIG. It is a figure for demonstrating the heat conduction path 1 and 2 from a capacitor in the capacitor module which concerns on embodiment. It is a figure which showed the temperature distribution inside the capacitor module which concerns on embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the elements common to each figure are designated by the same reference numerals, and duplicate description will be omitted or abbreviated. When the number, quantity, quantity, range, etc. of each element is referred to in the embodiment shown below, the number mentioned is not specified unless otherwise specified or clearly specified in principle. However, the present invention is not limited. In addition, the structures and the like described in the embodiments shown below are not necessarily essential to the present invention unless otherwise specified or clearly specified in principle.

1. 1. Capacitor cooling structure according to the embodiment First, the condenser structure according to the embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a perspective view showing the configuration of the capacitor 10 and its surroundings according to the embodiment. FIG. 2 is a perspective view showing the appearance of the capacitor module 1 including the capacitor 10. FIG. 3 is a diagram for explaining the configuration inside and around the capacitor case 12. In FIGS. 2 and 3, a part of the P bus bar 16 and the N bus bar 18, and the power card 20 and the cooler 24 are not shown.

1-1. Example of basic configuration (premise configuration) The capacitor module 1 includes a capacitor 10. The "capacitor" here is a combination of one or more capacitor elements. In the example shown in FIGS. 1 to 3, the capacitor 10 is configured by connecting three capacitor elements in parallel. The capacitor element is, for example, a film capacitor.

The capacitor 10 is housed in the capacitor case 12. The capacitor case 12 is made of resin, for example. More specifically, the capacitor 10 is sealed in the capacitor case 12 by a sealing member 14 (see FIG. 7 described later) such as resin filled in the capacitor case 12.

The capacitor 10 includes a pair of electrode surfaces and four non-electrode surfaces which are other outer surfaces as its outer surface. Specifically, as shown in FIG. 3, the pair of electrode surfaces are a positive electrode surface 10a and a negative electrode surface 10b. The four non-electrode surfaces are the upper surface 10c, the lower surface 10d, the side surface 10e, and the side surface opposite to the side surface 10e in the vertical direction of the paper surface of FIG. For convenience, it is referred to as "side surface F").

The capacitor module 1 further includes a positive electrode bus bar (also referred to as “P bus bar”) 16 and a negative electrode bus bar (also referred to as “N bus bar”) 18. Specifically, the P bus bar 16 is in contact with the positive electrode surface 10a, and the N bus bar 18 is in contact with the negative electrode surface 10b. As shown in FIG. 2, the P bus bar 16 and the N bus bar 18 project outward from the opening of the capacitor case 12.

In the example of the apparatus shown in FIGS. 1 to 3 to which the capacitor structure according to the present embodiment is applied, the P bus bar 16 and the N bus bar 18 transmit DC power between the capacitor 10 and the power card 20. The power card 20 is a card-shaped power semiconductor module formed by resin-molding a plurality of semiconductor elements (not shown) for power switching, and converts DC power from the capacitor 10 into AC power. The condenser cooling structure according to the present invention can be applied not only to a power semiconductor module formed as a card-shaped power card 20, but also to other power semiconductor modules such as those called IPMs (Intelligent Power Modules). ..

In the example shown in FIG. 1, a plurality of (six cards as an example) power cards 20 are stacked and arranged. Each power card 20 includes a power terminal 22. The power terminal 22 has a positive electrode terminal 22a and a negative electrode terminal 22b to which a DC voltage is applied, and an AC terminal 22c that outputs AC power. The P bus bar 16 and the N bus bar 18 described above are welded to the positive electrode terminal 22a and the negative electrode terminal 22b, respectively. Further, an AC bus bar (not shown) is welded to the AC terminal 22c.

The semiconductor element housed in the power card 20 is cooled by the cooler 24. As an example, the cooler 24 is a water-cooled type, and as shown in FIG. 1, includes a cooling plate 24a that is in contact with both sides of each power card 20 via grease and an insulating plate 26. The cooling of the power card 20 by such a cooler 24 is as follows. That is, a certain cooling plate 24a is in contact with the insulating plate 26 via grease, and the insulating plate 26 is in contact with one surface of the power card 20 via grease. The other surface of the power card 20 is in contact with the cooling plate 24a on the opposite side via grease, an insulating plate 26, and grease. As a result, each power card 20 is cooled from both sides thereof.

Then, as the power card 20 is cooled by the cooler 24 as described above, the P bus bar 16 and the N bus bar 18 connected to the positive electrode terminal 22a and the negative electrode terminal 22b of the power card 20, respectively, are separated by the cooler 24. It is cooled indirectly. In another example of the capacitor structure according to the present invention, the positive electrode (P) bus bar and the negative electrode (N) bus bar may be directly cooled by an arbitrary cooler.

In the examples shown in FIGS. 1 to 3 described above, the capacitor 10 is used to form a power conversion device such as an inverter. More specifically, the capacitor 10 is a smoothing capacitor as an example, for smoothing DC power from a battery (DC power supply) (not shown) and suppressing voltage fluctuation due to switching of a semiconductor element of the power card 20. Used for.

In addition, the capacitor module 1, the power card 20, and the cooler 24 are housed in an inverter case (not shown) as an example. Then, as shown in FIG. 3, the capacitor case 12 is mounted on the wall portion 30 of the inverter case via a high thermal conductivity sheet 28 having a high thermal conductivity. The capacitor case 12 is attached to a predetermined support portion (not shown) of the inverter case by using the attachment portion 12a.

1-2. Example of capacitor cooling structure The positive electrode (P) bus bar and the negative electrode (N) bus bar are generally connected to the electrodes of the capacitor so as to secure the energizing function. On the other hand, in the present embodiment, the P bus bar 16 and the N bus bar 18 are configured to have not only an energizing function but also a function of cooling the capacitor 10.

That is, in the capacitor cooling structure according to the present embodiment, not only the positive electrode surface 10a and the negative electrode surface 10b, which are a pair of electrode surfaces, but also the remaining four non-electrode surfaces, the upper surface 10c, the lower surface 10d, the side surface 10e, and the side surface F. Each of the above is also in contact with the P bus bar 16 or the N bus bar 18.

Specifically, first, as shown in FIG. 3, the upper surface 10c of the capacitor 10 is covered with the P bus bar 16 and is in contact with the P bus bar 16. More specifically, the P bus bar 16 is in contact with the upper surface 10c in the process of extending from the positive electrode surface 10a to the outside of the capacitor case 12 along the upper surface 10c. As a preferable example, the P bus bar 16 is formed so as to cover the upper surface 10c as a whole, and is in contact with the upper surface 10c in a wide range as much as possible.

Next, as an example, the lower surface 10d is covered with the N bus bar 18 and is in contact with the N bus bar 18. More specifically, the N bus bar 18 is formed so as to extend to the lower surface 10d along the negative electrode surface 10b and cover the lower surface 10d, and the lower surface 10d is in contact with the N bus bar 18. As a preferable example, the N bus bar 18 is formed so as to cover the lower surface 10d as a whole, and is in contact with the lower surface 10d in a wide range as much as possible.

Next, as an example, the side surface 10e is covered with the P bus bar 16 and is in contact with the P bus bar 16. More specifically, the side surface 10e is covered with a branch portion 16a of the P bus bar 16 branched from the portion of the P bus bar 16 in contact with the upper surface 10c, and is in contact with the branch portion 16a.

Next, the side surface F, which is not visible in FIG. 3, is covered with the N bus bar 18 as an example, and is in contact with the N bus bar 18. More specifically, the side surface F is covered with a branch portion of the N bus bar 18 branched from the portion of the N bus bar 18 in contact with the lower surface 10d, and is in contact with the branch portion.

In addition, in the example shown in FIG. 3, the P bus bar 16 and the N bus bar 18 are in contact with the positive electrode surface 10a and the negative electrode surface 10b in a wide range beyond the range necessary for ensuring the energizing function, respectively. Specifically, the P bus bar 16 extends to the vicinity of the lower end of the positive electrode surface 10a and is in general contact with the positive electrode surface 10a. The N bus bar 18 is in general contact with the negative electrode surface 10b in the process of extending to the lower surface 10d.

2. Effect Next, the effect of the capacitor structure according to the present embodiment will be described in comparison with the comparative example shown in FIG.

FIG. 4 is a perspective view for explaining the capacitor module 100 having only the energizing function according to the comparative example. The capacitor module 100 according to this comparative example is different from the capacitor module 1 according to the embodiment in the configuration of the P bus bar 102 and the N bus bar 104. Specifically, if only the energizing function is provided, it is sufficient that the P bus bar and the N bus bar are in contact with a part of the electrode surface. Therefore, in the comparative example, as shown in FIG. 4, the P bus bar 102 is in contact with a part of the positive electrode surface 10a, and the N bus bar 104 is in contact with a part of the negative electrode surface 10b. In other words, in the comparative example, the PN bus bars 102 and 104 are in contact with the electrode surfaces 10a and 10b only within the range necessary for the energizing function.

The part of the capacitor module that gets hot is the capacitor element. FIG. 5 is a diagram showing the internal temperature distribution of the capacitor module 100 (comparative example) shown in FIG. Also in the comparative example shown in FIG. 5, the capacitor 10 (collection of capacitor elements) is arranged in the capacitor case 12 filled with the same sealing member as the sealing member 14, as in the present embodiment.

In this comparative example, which does not focus on cooling the capacitor 10 by using the PN bus bar, as described above, the P bus bar 102 and the N bus bar 104 are each limited to the range necessary for ensuring the energizing function. It is not in contact with the positive electrode surface 10a and the negative electrode surface 10b. As a result, in the structure according to this comparative example, as shown in FIG. 5, a high temperature value T1 is exhibited in the central portion of the capacitor 10 (capacitor element), and the capacitor 10 becomes hot in a wide region around the capacitor 10. ing. That is, in this structure, the heat of the capacitor 10 (capacitor element) (particularly, the heat of the central portion thereof) cannot be efficiently released to the outside.

FIG. 6 is a diagram for explaining the heat conduction paths 1 and 2 from the capacitor 10 in the capacitor module 1 according to the embodiment. In the structure of the capacitor module 1, from the inside to the outside, the capacitor 10 (capacitor element), the PN bus bars 16 and 18, the sealing member 14 (for example, resin) and the capacitor case 12 (for example, resin) are in this order. ing. There are two heat transfer paths from the capacitor 10 to the outside, the following heat conduction path 1 and heat conduction path 2.

Specifically, the heat conduction path 1 corresponds to a path in which the heat dissipation effect of the capacitor 10 is promoted by the configuration of the P bus bar 16 and the N bus bar 18 according to the present embodiment. In the heat conduction path 1, the heat of the capacitor 10 (capacitor element) is first transferred to each of the P bus bar 16 and the N bus bar 18 as shown by arrows in FIG. The heat transferred to the P bus bar 16 is transferred to each power card 20 via each positive electrode terminal 22a. The heat transferred to the N bus bar 18 is transferred to each power card 20 via each negative electrode terminal 22b. The heat transferred to each power card 20 is transferred to the cooler 24 (cooling plate 24a) via the grease, the insulating plate 26, and the grease. The heat transferred to the cooler 24 is finally transferred to the cooling water flowing in the cooler 24.

According to the capacitor cooling structure according to the present embodiment, not only the positive electrode surface 10a and the negative electrode surface 10b, which are a pair of electrode surfaces, but also the remaining four non-electrode surfaces, the upper surface 10c, the lower surface 10d, the side surface 10e, and the side surface F. (In the examples shown in FIGS. 1 to 3, all non-electrode surfaces) are also in contact with the P bus bar 16 or the N bus bar 18. That is, according to this capacitor cooling structure, the P bus bar 16 or the N bus bar 18 is in contact with each of the non-electrode surfaces that are not used for energization. Therefore, the heat transfer area between the capacitor 10 and the PN bus bars 16 and 18 can be increased, and the heat dissipation effect from the capacitor 10 to the PN bus bars 16 and 18 can be effectively improved. As described above, the P bus bar 16 and the N bus bar 18 have not only a function of energizing but also a function of cooling the capacitor 10.

FIG. 7 is a diagram showing the temperature distribution inside the capacitor module 1 according to the embodiment. More specifically, FIG. 7 shows the temperature distribution under the same usage conditions of the capacitor 10 as in FIG.

According to the condenser cooling structure according to the present embodiment, as described above, the heat dissipation effect from the condenser 10 to the PN bus bars 16 and 18 is effectively enhanced. Therefore, heat conduction (heat dissipation) from the condenser 10 to the cooler 24 via the PN buses 16 and 18 by the heat conduction path 1 can be effectively performed.

As a result, as shown in FIG. 7, the temperature distribution inside the capacitor 10 is improved as compared with the comparative example shown in FIG. More specifically, in the present embodiment, the temperature at the center of the capacitor 10, which has the highest temperature, is lowered to a temperature value T2 lower than the temperature value T1 of the comparative example. Further, the temperature of the region around the central portion is also satisfactorily lowered as compared with the comparative example.

As described above, according to the condenser cooling structure according to the present embodiment, by using the PN bus bars 16 and 18 having not only the energizing function but also the function of cooling the capacitor 10, the heat dissipation effect of the condenser element using the bus bar can be obtained. It can be improved satisfactorily.

In addition, in the heat conduction path 2, the heat of the capacitor 10 (capacitor element) is sequentially transferred to the sealing member 14 and the capacitor case 12 via the P bus bar 16 or the N bus bar 18. The heat transferred to the capacitor case 12 is transferred to the wall portion 30 of the inverter case via the high thermal conductive sheet 28 as shown by an arrow in FIG. The heat transferred to the wall portion 30 is finally released to the outside air. According to the structural example of the present embodiment, the heat dissipation effect of the capacitor element can be enhanced by also utilizing such a heat conduction path 2.

3. 3. Deformation example (another formation example of PN bus bar)
In the above-described embodiment, as shown in FIG. 3, of the four non-electrode surfaces, the upper surface 10c and the side surface 10e are in contact with the P bus bar 16, and the lower surface 10d and the side surface F are in contact with the N bus bar 18. According to such an example of forming the PN bus bar, the PN bus bar can be provided with the energizing function and the cooling function of the capacitor 10 while suppressing the complication of the shape of each PN bus bar. However, the bus bar in contact with each of these four non-electrode surfaces is not necessarily limited to the above example. That is, the PN bus bar may be formed in a combination different from the above example so that each of the four non-electrode surfaces is in contact with the P bus bar or the N bus bar. Further, at least one non-electrode surface of the plurality of non-electrode surfaces included in the capacitor is provided with both the P bus bar and the N bus bar on the condition that the P bus bar and the N bus bar do not come into contact with each other on the non-electrode surface. You may touch it.

The examples described in the above-described embodiments and the other modifications may be appropriately combined within a possible range other than the specified combinations, and various modifications may be made without departing from the spirit of the present invention. You may.

1,100 Capacitor module 10 Capacitor 10a Positive electrode surface of capacitor 10b Negative electrode surface of capacitor 10c Top surface of capacitor 10d Bottom surface of capacitor 10e Side surface of capacitor 12 Capacitor case 14 Sealing member 16, 102 Positive electrode bus bar (P bus bar)
18,104 Negative electrode bus bar (N bus bar)
20 Power card 22a Positive terminal of power card 22b Negative terminal of power card 24 Cooler 26 Insulation plate 28 High heat conduction sheet 30 Wall of inverter case

Claims (1)

A capacitor including a capacitor element and having a positive electrode surface and a negative electrode surface as outer surfaces and a plurality of non-electrode surfaces which are outer surfaces other than the positive electrode surface and the negative electrode surface.
A positive electrode bus bar in contact with the positive electrode surface and
The negative electrode bus bar in contact with the negative electrode surface and
A cooler that directly or indirectly cools the positive electrode bus bar and the negative electrode bus bar,
It is a condenser cooling structure equipped with
A condenser cooling structure, wherein each of the plurality of non-electrode surfaces is in contact with at least one of the positive electrode bus bar and the negative electrode bus bar.

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