JP2009218285A - Capacitor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacitor device which suppresses vibrations without making capacitance small by reducing variations in amplitude among a plurality of capacitive elements. <P>SOLUTION: The capacitor device 1 is constituted by connecting the plurality of capacitive elements 2, each constituted by winding a metallized film, in parallel between a positive-electrode bus plate 31 and a negative-electrode bus plate 32. The positive-electrode bus plate 31 and negative-electrode bus plate 32 are provided with a positive-electrode external terminal 41 and a negative-electrode external terminal 42 to be connected to an external power source, respectively. The capacitive elements 2 each have a pair of electrode terminals 21 connected to the positive-electrode bus plate 3 and negative-electrode bus plate 32. A capacitive element 2 which is shorter in total electric path length as the sum of an electric path length between the positive-electrode external terminal 41 of the positive-electrode bus plate 31 and the electrode terminal 21 and an electric path length between the negative-electrode external terminal 42 of the negative-electrode plate 32 and the electrode terminal 21 among the plurality of capacitive elements 2 is smaller in volume. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a capacitor device in which a plurality of capacitor elements configured by winding a metallized film are connected in parallel between a positive electrode bus plate and a negative electrode bus plate.

Conventionally, there is a capacitor device in which a plurality of capacitor elements configured by winding a metallized film are connected in parallel (Patent Document 1, etc.).
The capacitor device is disposed as a component part of a power conversion device such as an inverter used in a hybrid vehicle or an electric vehicle, for example.
In such a capacitor device, a plurality of capacitor elements of the same size are arranged side by side, for example, linearly or planarly.

JP 2004-319799 A

However, the capacitor device may vibrate when a current is passed through the capacitor element, and the vibration may propagate to a vehicle or the like to generate a vibration sound. That is, the ripple of ripple current out of the current flowing in the capacitor element causes the capacitor element to vibrate by repeating expansion and contraction of the metallized film at a high frequency.
Therefore, the larger the ripple current that flows, the larger the amplitude of the capacitor element.

  By the way, in a capacitor | condenser apparatus, when connecting a some capacitor | condenser element in parallel, a pair of electrode terminal of each capacitor | condenser element is electrically connected to a pair of bus bar. In general, an external terminal for connection to an external power source is formed at one place in each of the pair of bus bars, but the distance between the external terminal and each capacitor element is different. That is, the sum total of the electric circuit length (total electric circuit length) between each external terminal and the electrode terminal of the capacitor element in the pair of bus bars is different for each capacitor element.

The longer the total circuit length, the more the ripple current supplied from the power source to each capacitor element can be suppressed by the wiring inductance of the bus bar. Therefore, the capacitor element having a long total circuit length with respect to the external terminal has a relatively small amplitude, but the capacitor element having a short total circuit length with the external terminal has a large amplitude. . As described above, since the amplitude is not uniform among the capacitor elements, there is a problem that the vibration of the entire capacitor device is increased.
Further, if the size of all the capacitor elements is simply reduced uniformly in order to reduce the amplitude, the capacitance of the capacitor elements is reduced, and the capacitance of the capacitor device is reduced.

  The present invention has been made in view of such conventional problems, and it is an object of the present invention to provide a capacitor device that reduces variation in amplitude of a plurality of capacitor elements and suppresses vibration without reducing capacitance. is there.

The present invention is a capacitor device formed by connecting a plurality of capacitor elements formed by winding a metallized film in parallel between a positive electrode bus plate and a negative electrode bus plate,
The positive bus plate and the negative bus plate are respectively provided with a positive external terminal and a negative external terminal for connection to an external power source,
The capacitor element has a pair of electrode terminals connected to the positive electrode bus plate and the negative electrode bus plate, respectively.
Among the plurality of capacitor elements, an electrical path length between the positive external terminal and the electrode terminal in the positive bus plate, and an electrical path length between the negative external terminal and the electrode terminal in the negative bus plate. The capacitor element having a shorter total electric circuit length, which is the sum, has a smaller volume (claim 1).

Next, the effects of the present invention will be described.
As described above, the longer the total electric circuit length, the smaller the ripple current that causes the vibration of the capacitor element due to the wiring inductance of the positive electrode bus plate and the negative electrode bus plate. Conversely, the shorter the total circuit length, the greater the ripple current flowing through the capacitor element.

  Therefore, in the capacitor device of the present invention, the plurality of capacitor elements are arranged so that the volume of the capacitor element with the shorter total circuit length is smaller. That is, the volume of the capacitor element with a short total electric circuit length through which a large ripple current flows is reduced. Thereby, the amplitude of the capacitor element can be reduced.

  On the other hand, a capacitor element with a small ripple current flowing and a long total circuit length originally has a relatively small amplitude. Therefore, even if the volume is larger than a capacitor element with a short total circuit length, the amplitude does not become too large. Then, by increasing the volume of the capacitor element having a long total electric circuit length, the capacitance of the capacitor element can be increased.

  Therefore, it is possible to reduce variation in amplitude among the plurality of capacitor elements while ensuring a sufficient capacitance as the entire capacitor device. As a result, vibration can be suppressed without reducing the capacitance of the capacitor device.

  As described above, according to the present invention, it is possible to provide a capacitor device that reduces variations in amplitude of a plurality of capacitor elements and suppresses vibration without reducing capacitance.

In the present invention (Claim 1), “the capacitor element having a shorter total circuit length has a smaller volume” not only means that the volume of the capacitor element gradually increases as the total circuit length increases. This includes the case where the volume of the capacitor element gradually increases.
The metallized film constituting the capacitor element is formed by evaporating a metal layer on the surface of a resin film (dielectric), for example. Examples of the resin film include resin films made of polyethylene terephthalate (PET), polypropylene (PP), polyethylene naphthalate (PEN), polyphenylene sulfide (PPS), polycarbonate (PC), and the like. Moreover, as a metal of a metal layer, aluminum, zinc, these alloys, etc. are mentioned.

Moreover, it is preferable that the cross-sectional area of the cross section orthogonal to the winding axis direction is smaller as the capacitor element has a shorter total electric circuit length.
In this case, it is possible to easily provide a capacitor device in which the volume of the capacitor element is adjusted to reduce the variation in the amplitude of the plurality of capacitor elements, and the vibration is suppressed without reducing the capacitance.

In addition, the capacitor element having a shorter total electric circuit length may have a lower height in the winding axis direction (Claim 3).
Also in this case, it is possible to easily provide a capacitor device in which the volume of the capacitor element is adjusted to reduce variations in the amplitude of the plurality of capacitor elements, and the vibration is suppressed without reducing the capacitance.

Further, the plurality of capacitor elements are arranged along a certain direction, and the positive external terminal and the negative external terminal are arranged at the same position with respect to the arrangement direction of the capacitor elements. Preferred (claim 4).
In this case, it is easy to connect an external power source to the positive external terminal and the negative external terminal, and it is easy to simplify the arrangement and wiring of the capacitor device and its peripheral devices.

Moreover, it is preferable that the said capacitor | condenser apparatus comprises a part of power converter device (Claim 5).
In this case, the vibration of the power conversion device can be effectively suppressed.
Examples of the power converter include a DC-DC converter and an inverter. Moreover, the said power converter device can be used for the production | generation of the drive current which supplies with electricity to the alternating current motor which is motive power sources, such as an electric vehicle and a hybrid vehicle, for example.

Example 1
A capacitor device according to an embodiment of the present invention will be described with reference to FIGS.
As shown in FIGS. 1 and 3, the capacitor device 1 of this example includes a plurality of capacitor elements 2 (FIG. 5) configured by winding a metallized film 22 between a positive electrode bus plate 31 and a negative electrode bus plate 32. Connected in parallel.

As shown in FIG. 4, the positive electrode bus plate 31 and the negative electrode bus plate 32 are respectively provided with a positive electrode external terminal 41 and a negative electrode external terminal 42 for connection to an external power source.
As shown in FIGS. 1 and 3, the capacitor element 2 has a pair of electrode terminals 21 connected to a positive electrode bus plate 31 and a negative electrode bus plate 32, respectively.

  As shown in FIG. 2, among the plurality of capacitor elements 2, the electric path length Lp between the positive electrode external terminal 41 and the electrode terminal 21 in the positive electrode bus plate 31, and the negative electrode external terminal 42 and the electrode terminal in the negative electrode bus plate 32. The capacitor element 2 has a smaller volume as the total circuit length Ls (= Lp + Ln), which is the sum total of the circuit length Ln between 21 and 21, is smaller.

  In this example, as means for changing the volume of the capacitor element 2, means for changing the cross-sectional area of the cross section orthogonal to the winding axis direction Z is adopted. In other words, the capacitor element 2 having a shorter total circuit length Ls has a smaller cross-sectional area of a cross section perpendicular to the winding axis direction Z (cross section of the capacitor element 2 shown in FIG. 2).

  For example, a description will be given by comparing the capacitor element 2a and the capacitor element 2b shown in FIG. The total circuit length Ls (= Lp + Ln) which is the sum of the circuit length Lp and the circuit length Ln in the capacitor element 2a, and the total circuit length Ls (= Lp + Ln) which is the sum of the circuit length Lp and the circuit length Ln in the capacitor element 2b. And the total electric circuit length Ls in the capacitor element 2a is shorter. Therefore, the capacitor element 2a has a smaller volume than the capacitor element 2b.

The plurality of capacitor elements 2 are arranged along a certain direction A. The positive external terminal 41 and the negative external terminal 42 are disposed at the same position with respect to the arrangement direction A of the capacitor elements 2.
For example, as shown in FIG. 2, a plurality of capacitor elements 2 are arranged in parallel along a certain direction A in two columns. A positive external terminal 41 and a negative external terminal 42 are disposed near one end in the direction A of the capacitor device 1. The plurality of capacitor elements 2 are arranged toward the other end side in the direction A in the capacitor device 1 rather than the positive electrode external terminal 41 and the negative electrode external terminal 42.

In this arrangement direction A, the volume (cross-sectional area) of the capacitor element 2 gradually increases from one end side where the positive electrode external terminal 41 and the negative electrode external terminal 42 are disposed to the other end side.
In this example, as shown in FIG. 3, the height in the winding axis direction Z of the plurality of capacitor elements 2 is constant.

  As shown in FIG. 5, the capacitor element 2 is wound with a metal film 22 formed by depositing a metal layer on the surface of a resin film (dielectric), and then pressed by two planes parallel to the winding axis direction Z. Configured. As shown in FIGS. 1 and 3, the capacitor elements 2 are arranged in parallel inside the case 11 with the winding axis direction Z as the height direction.

  The metallized film 22 constituting the capacitor element 2 is formed by depositing a metal layer on the surface of a resin film (dielectric). Examples of the resin film include resin films made of polyethylene terephthalate (PET), polypropylene (PP), polyethylene naphthalate (PEN), polyphenylene sulfide (PPS), polycarbonate (PC), and the like. Moreover, as a metal of a metal layer, aluminum, zinc, these alloys, etc. are mentioned.

Metallicon metal is thermally sprayed on both end faces in the winding axis direction Z of the capacitor element 2, and the metallicon metal becomes the electrode terminals 21 of the capacitor element 2. As shown in FIGS. 1, 3, and 4, the positive electrode bus plate 31 and the negative electrode bus plate respectively connected to the pair of electrode terminals 21 of the plurality of capacitor elements 2 on the upper end surface and the lower end surface of the capacitor element 2. 32 is disposed. The positive electrode bus plate 31 and the negative electrode bus plate 32 are molded together with the capacitor element 2 by the molding material 12 inside the case 11. A positive electrode external terminal 41 and a negative electrode external terminal 42 exposed from the molding material 12 are connected to the positive electrode bus plate 31 and the negative electrode bus plate 32, respectively.
In addition, the positive electrode bus plate 31 and the negative electrode bus plate 32 are not restricted to said arrangement | positioning relationship, For example, the arrangement | positioning reverse may be sufficient.

  The mold material 12 is made of, for example, an epoxy resin or a urethane resin. The case 11 is made of, for example, polyethylene terephthalate (PET), polypropylene (PP), polyphenylene sulfide (PPS), polycarbonate (PC), polybutylene terephthalate (PBT), or the like.

Next, the function and effect of this example will be described.
As described above, the longer the total circuit length Ls, the smaller the ripple current that causes vibration of the capacitor element 2 due to the wiring inductance of the positive electrode bus plate 31 and the negative electrode bus plate 32. Conversely, the shorter the total circuit length Ls, the larger the ripple current flowing through the capacitor element 2.

  Therefore, in the capacitor device 1 of the present invention, a plurality of capacitor elements 2 are arranged so that the volume of the capacitor element 2 having a shorter total circuit length Ls becomes smaller. That is, the volume of the capacitor element 2 (for example, the capacitor element 2a in FIG. 2) having a short total circuit length Ls through which a large ripple current flows is reduced. Thereby, the amplitude of the capacitor element 2 can be reduced.

  On the other hand, the capacitor element 2 (for example, the capacitor element 2b in FIG. 2) having a small total ripple length Ls and a small total ripple current is originally relatively small in amplitude, and therefore has a larger volume than the capacitor element 2 having a short total path length Ls. However, the amplitude does not become too large. Then, by increasing the volume of the capacitor element 2 having a long total circuit length Ls, the capacitance of the capacitor element 2 can be increased.

  Therefore, the variation in amplitude among the plurality of capacitor elements 2 can be reduced while ensuring a sufficient capacitance as the entire capacitor device 1. As a result, vibration can be suppressed without reducing the capacitance of the capacitor device 1.

  In this example, the capacitor element 2 having a shorter total electric circuit length Ls has a smaller cross-sectional area perpendicular to the winding axis direction Z. Therefore, the capacitor device 1 can be easily obtained by adjusting the volume of the capacitor element 2 to reduce variations in the amplitude of the plurality of capacitor elements 2 and suppressing vibration without reducing the capacitance.

  The plurality of capacitor elements 2 are arranged along a certain direction A, and the positive external terminal 41 and the negative external terminal 42 are arranged at the same position with respect to the arrangement direction of the capacitor elements 2. Therefore, it is easy to connect an external power source to the positive electrode external terminal 41 and the negative electrode external terminal 42, and it becomes easy to simplify the arrangement and wiring of the capacitor device 1 and its peripheral devices.

  As described above, according to this example, it is possible to provide a capacitor device that reduces variations in amplitude of a plurality of capacitor elements and suppresses vibration without reducing capacitance.

(Example 2)
This example is an example of the capacitor device 1 in which the height in the winding axis direction Z is lower as the capacitor element 2 has a shorter total circuit length Ls as shown in FIGS. 6 and 7.
That is, as shown in FIG. 7, the capacitor element 2 closer to the positive electrode external terminal 41 and the negative electrode external terminal 42 has a smaller height in the winding axis direction Z. Further, due to the difference in height between the capacitor elements 2, a gap is generated between the capacitor elements 2 other than the capacitor element 2 having the largest height and the positive electrode bus plate 31. Therefore, a connection wiring 13 that electrically connects both the electrode terminals 21 and the positive electrode bus plate 31 in the capacitor elements 2 is separately provided.

Capacitor element 2 may be arranged such that a gap is formed between negative electrode bus bar 32 and capacitor element 2. In this case, a connection wiring for electrically connecting the two electrode terminals 21 and the negative electrode bus plate 32 in the capacitor elements 2 is separately provided.
Moreover, in this example, as shown in FIG. 6, the cross-sectional area of the cross section orthogonal to the winding axis direction Z of the plurality of capacitor elements 2 is constant.
Others are the same as in the first embodiment.

Also in the case of this example, the capacitor device 1 that easily adjusts the volume of the capacitor element 2 to reduce the variation in the amplitude of the plurality of capacitor elements 2 and suppresses the vibration without reducing the capacitance is obtained. be able to.
In addition, the same effects as those of the first embodiment are obtained.

(Example 3)
This example is an example of the capacitor device 1 in which a plurality of capacitor elements 2 are arranged so that the volume of the capacitor element 2 increases stepwise as the total electric circuit length Ls becomes longer, as shown in FIGS.

  For example, as shown in FIG. 8, twelve capacitor elements 2 are divided into three groups in order from those close to the positive electrode external terminal 41 and the negative electrode external terminal 42 (the total electric circuit length Ls is long), and the capacitor elements in each group. The volume of 2 is made equal. Then, the volume of the capacitor element 2c in the group having the shortest total circuit length Ls is minimized, the volume of the capacitor element 2e in the group having the longest total circuit length Ls is maximized, and the capacitor in the group having the total circuit path length Ls is intermediate. The volume of the element 2d is set to an intermediate size.

In this example, the difference in volume of the capacitor element 2 between the groups is given by the difference in the cross-sectional area of the cross section perpendicular to the winding axis direction Z. That is, as shown in FIG. 8, the cross-sectional area of the capacitor element 2 increases stepwise as the total electric circuit length Ls increases.
Others are the same as in the first embodiment.

In the case of this example, since the number of types of capacitor elements 2 having different volumes can be reduced, the production efficiency of the capacitor device 1 can be improved and the manufacturing cost can be reduced.
In addition, the same effects as those of the first embodiment are obtained.

In Example 3, the difference in volume of the capacitor element 2 between the groups is given by the difference in the cross-sectional area of the cross section orthogonal to the winding axis direction Z. It can also be applied by the difference in height in the axial direction Z.
In the present invention, the means for changing the volume of the capacitor element is not limited to the means shown in the first to third embodiments, and the cross-sectional area of the cross section orthogonal to the winding axis direction Z and the winding axis direction Z It is possible to adopt a means for changing both of the height and other means.

(Comparative example)
This example is an example of a capacitor device 9 in which the volumes of a plurality of capacitor elements 2 are all equal, as shown in FIGS.
That is, the plurality of capacitor elements 2 are aligned with the same cross-sectional area perpendicular to the winding axis direction Z and the same height in the winding axis direction Z.
Others are the same as in the first embodiment.

  In the case of this example, the longer the total circuit length Ls (= Lp + Ln) between the positive electrode external terminal 41 and the negative electrode external terminal 42, the larger the ripple current that flows and the amplitude becomes extremely large. . That is, there is a problem that the amplitude is not uniform between the capacitor elements 2 and the overall vibration of the capacitor device 9 is increased.

  Specifically, for example, when comparing the capacitor element 2 f and the capacitor element 2 g shown in FIG. 10, the sum of the electric circuit length Lp between the positive electrode external terminal 41 and the electric circuit length Ln between the negative electrode external terminal 42. The total electric circuit length Ls (= Lp + Ln) is overwhelmingly shorter in the capacitor element 2f. For this reason, when the capacitor element 2f and the capacitor element 2g are composed of elements having the same volume, the amplitude of the capacitor element 2f becomes extremely larger than that of the capacitor element 2g.

  Further, if the size of all the capacitor elements 2 is simply reduced uniformly to reduce the amplitude, the capacitance of all the capacitor elements 2 is reduced, and the capacitance of the capacitor device 9 is reduced. End up.

  On the other hand, as described above, the capacitor device 1 of the present invention (Examples 1 to 3) has a smaller volume as the capacitor element 2 has a shorter total circuit length Ls. Variation can be reduced and vibration can be suppressed without reducing capacitance.

FIG. 3 is a perspective view of the capacitor device according to the first embodiment. Sectional explanatory drawing of the capacitor | condenser apparatus by the plane orthogonal to the winding axis direction Z of a capacitor | condenser element in Example 1. FIG. FIG. 3 is a sectional view taken along line B-B in FIG. 2. The CC sectional view taken on the line of FIG. FIG. 3 is a perspective view of a capacitor element according to the first embodiment. Sectional explanatory drawing of the capacitor | condenser apparatus by the plane orthogonal to the winding axis direction Z of a capacitor | condenser element in Example 2. FIG. The DD sectional view taken on the line of FIG. Sectional explanatory drawing of the capacitor | condenser apparatus by the plane orthogonal to the winding axis direction Z of a capacitor | condenser element in Example 3. FIG. FIG. 9 is a cross-sectional view taken along line EE in FIG. 8. Sectional explanatory drawing of the capacitor | condenser apparatus by the plane orthogonal to the winding axis direction Z of a capacitor | condenser element in a comparative example. FIG. 11 is a cross-sectional view taken along line FF in FIG. 10.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Capacitor apparatus 2 Capacitor element 21 Metallized film 31 Positive electrode bus plate 32 Negative electrode bus plate 41 Positive electrode external terminal 42 Negative electrode external terminal

Claims (5)

A capacitor device in which a plurality of capacitor elements configured by winding a metallized film are connected in parallel between a positive electrode bus plate and a negative electrode bus plate,
The positive bus plate and the negative bus plate are respectively provided with a positive external terminal and a negative external terminal for connection to an external power source,
The capacitor element has a pair of electrode terminals connected to the positive electrode bus plate and the negative electrode bus plate, respectively.
Among the plurality of capacitor elements, an electrical path length between the positive external terminal and the electrode terminal in the positive bus plate, and an electrical path length between the negative external terminal and the electrode terminal in the negative bus plate. A capacitor device having a smaller volume as the capacitor element has a shorter total electric circuit length as a sum.   2. The capacitor device according to claim 1, wherein the capacitor element having a shorter total electric circuit length has a smaller cross-sectional area of a cross section perpendicular to the winding axis direction.   3. The capacitor device according to claim 1, wherein the capacitor element having a shorter total electric circuit length has a lower height in the winding axis direction.   The capacitor elements according to any one of claims 1 to 3, wherein the plurality of capacitor elements are arranged along a certain direction, and the positive electrode external terminal and the negative electrode external terminal are mutually connected with respect to the arrangement direction of the capacitor elements. A capacitor device which is arranged at the same position.   5. The capacitor device according to claim 1, wherein the capacitor device constitutes a part of a power conversion device. 6.

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