JP2011124434A - Capacitor module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacitor module effectively lowering heating value by uniformizing a current distribution of a capacitor element. <P>SOLUTION: The capacitor module 1 has: the capacitor element 2 formed by winding a metallized film and providing a pair of electrode surfaces 21p, 21n at both ends in a winding-axis direction; and a pair of bus bars 3p, 3n having one-end sides connected to the pair of electrode surfaces 21p, 21n and provided with external terminals at the other-end sides. The bus bars 3p, 3n are each formed by providing three or more connection portions 4 for the electrode surfaces 21p, 21n of the capacitor element 2. The connection portions 4 are disposed such that a winding center axis A of the capacitor element 2 exists within a polygon having largest area among polygons formed by connecting some of three or more connection portions 4 to each other with straight lines. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a capacitor module in which a pair of bus bars are connected to a pair of electrode surfaces of a capacitor element.

For example, as shown in FIG. 12, a capacitor element 92 formed by winding a metallized film and having a pair of electrode surfaces 921p and 921n at both ends in the winding axis direction, and one end on each of the pair of electrode surfaces 921p and 921n. And a capacitor module 9 having a pair of bus bars 93p and 93n provided with external terminals at the other end.
The bus bars 93p and 93n are connected to the electrode surfaces 921p and 921n by solder or the like, but the connecting portion 94 is usually in one or two places. The positions of the connecting portions 94 on the electrode surfaces 921p and 921n are often arranged at biased positions as shown in FIG.

However, when the connecting portion 94 is arranged at such a biased position, when a current flows in the capacitor element 92 from one (positive electrode side) electrode surface 921p toward the other (negative electrode side) electrode surface 921n. The current distribution in the capacitor element 92 becomes non-uniform. That is, current is likely to concentrate on the shortest path from the connecting portion 94 with the bus bar 93p on one electrode surface 921p to the connecting portion 94 with the bus bar 93n on the other electrode surface 921n. As a result, for example, in the state shown in FIG. 12, in the case where the connection portions 94 on the pair of electrode surfaces 921p and 921n are arranged at positions offset to the left side of the drawing, the current distribution on the left side of the capacitor element 92 in the drawing (Current path I) is biased.
In particular, as the current flowing through the capacitor element 92 becomes higher, the current is more likely to be concentrated at the shortest distance, so that the current distribution is more uneven. As a result, the amount of heat generated in the capacitor element 92 increases, and the temperature rise may cause a problem.

  To solve this problem, as shown in FIG. 13, a capacitor module 90 has been proposed in which a connection portion 94 on one electrode surface 921p and a connection portion 94 on the other electrode surface 921n are arranged at asymmetric positions (patent). Reference 1). That is, the connecting portion 94 on one electrode surface 921p is disposed at a position biased to the left side of the drawing, and the connecting portion 94 on the other electrode surface 921n is disposed at a position biased to the right side of the drawing. As a result, current flows in the capacitor element 92 obliquely with respect to the winding axis direction, so that the current distribution can be easily spread over the entire capacitor element 92.

JP 2008-258405 A

However, in the invention described in Patent Document 1 as well, although the direction of current flow is oblique with respect to the winding axis direction, the connection portion 94 on one electrode surface 921p to the connection portion 94 on the other electrode surface 921n. There is no change in that the current concentrates on the straight path (current path I) toward.
As the flowing current becomes higher in frequency, this current concentration becomes more conspicuous, and the problem that the amount of heat generated by the capacitor element 92 increases cannot be solved.
Moreover, since the impedance of the current path I increases as the current frequency increases, there is a problem that the amount of heat generation is further increased.

  The present invention has been made in view of such problems, and aims to provide a capacitor module capable of equalizing the current distribution in the capacitor element and effectively suppressing the amount of heat generation.

The present invention comprises a capacitor element formed by winding a metallized film and having a pair of electrode surfaces at both ends in the winding axis direction, one end connected to each of the pair of electrode surfaces, and an external terminal at the other end. A capacitor module having a pair of bus bars provided,
The bus bar is provided with three or more connecting portions with the electrode surface of the capacitor element,
Among the polygons formed by connecting at least a part of the three or more connecting portions with straight lines, the winding center axis of the capacitor element exists inside the largest polygon having the largest area. The capacitor module is characterized in that the connecting portion is arranged (claim 1).

  In the capacitor module, the bus bar is provided with three or more connecting portions to the electrode surface of the capacitor element. Therefore, the current is divided into three or more connecting portions from one (positive electrode side) bus bar, and then introduced into the capacitor element via one (positive electrode side) electrode surface. Then, the current flowing in the capacitor element flows from the three or more connecting portions to the other (negative electrode side) bus bar via the other (negative electrode side) electrode surface.

  At this time, since the current tends to flow mainly in the shortest distance, the current path in the capacitor element is mainly directed from the connection portion on one electrode surface to the connection portion on the other electrode surface. Since three or more connection portions are provided, at least three main current paths are formed in the capacitor element. As a result, the current can be easily distributed over the entire capacitor element.

Further, the connecting portion is arranged so that the winding central axis of the capacitor element exists inside the maximum polygon. By arranging the connection portions under such conditions, the distribution of the connection portions can be easily spread over the entire electrode surface. That is, it becomes difficult to form the connection portion at a biased position. As a result, a current path from the connection portion on one electrode surface to the connection portion on the other electrode surface is easily formed throughout the capacitor element.
As a result, current concentration in the capacitor element can be prevented, the amount of heat generated by the capacitor element can be suppressed, and the temperature rise can be suppressed.

In particular, when the frequency of the current flowing through the capacitor element is increased, the current is more likely to flow linearly over the shortest distance. However, in this case as well, current concentration in the capacitor element is suppressed and the amount of heat generated by the capacitor element increases. It can be prevented from being too much. That is, it is possible to obtain a capacitor module excellent in adaptability to a high frequency current.
In addition, as the current frequency increases, the impedance in the current path also increases, so the amount of heat generation increases. In this case, the current distribution is equalized as described above, so that the heat generation amount of the capacitor element is increased. Can be effectively suppressed.

  As described above, according to the present invention, it is possible to provide a capacitor module capable of equalizing the current distribution in the capacitor element and effectively suppressing the heat generation amount.

Sectional drawing by the plane containing the winding center axis | shaft of a capacitor | condenser module in Example 1. FIG. The top view seen from the winding axis direction of the capacitor | condenser module in Example 1. FIG. FIG. 3 is a perspective view of the capacitor element showing the arrangement of connection portions in the first embodiment. The top view of the electrode surface which showed arrangement | positioning of the connection part in Example 1. FIG. Explanatory drawing of the largest polygon. Explanatory drawing of the largest polygon following FIG. 1 is a perspective view of a capacitor module having a plurality of capacitor elements in Example 1. FIG. 1 is a plan view of a capacitor module having a plurality of capacitor elements in Example 1. FIG. The top view seen from the winding axis direction of the capacitor | condenser module in Example 2. FIG. The top view seen from the winding axis direction of the capacitor | condenser module in Example 3. FIG. The top view seen from the winding axis direction of the capacitor | condenser module in Example 4. FIG. Sectional drawing by the plane containing the winding center axis | shaft of a capacitor | condenser module in a prior art example. Sectional drawing by the plane containing the winding center axis | shaft of a capacitor | condenser module in another prior art example.

In the present invention, the connection portions provided on one of the electrode surfaces and the connection portions provided on the other electrode surface are arranged on the same straight line parallel to the winding center axis. (Claim 2).
In this case, since the distance between the pair of connection parts arranged on the same straight line can be made constant and shortest, the impedance of the current path between the connection parts can be made constant and minimum. Thereby, the current distribution in the capacitor element can be made more uniform, and the amount of generated heat can be further suppressed.

In addition, on a straight line passing through the electrode center point that is the intersection of the winding center axis and the electrode surface and the connection portion, the distance between the electrode center point and the connection portion, and the connection portion and the electrode surface It is preferable that the ratio of the distance to the outer peripheral edge is constant for all the connecting portions provided on the electrode surface.
In this case, the arrangement of the connection portions on the electrode surface can be easily dispersed evenly over the entire electrode surface. Therefore, it becomes easier to equalize the current distribution in the capacitor element.

The bus bar main body extends in a direction orthogonal to the winding center axis, and is based on a straight line that is parallel to the extending direction of the bus bar main body and passes through the electrode center point. Further, it is preferable that the three or more connecting portions are arranged so as to be line symmetric.
In this case, it is possible to equalize the arrangement of the connecting portions on the electrode surface, and to effectively prevent the current distribution in the capacitor element from being biased.

  The main body of the bus bar extends in a direction orthogonal to the winding central axis, and the electrode surface is orthogonal to the extending direction of the main body of the bus bar and the electrode center point. The first region and the second region are divided into a first region on the side where the body portion of the bus bar is extended and a second region on the opposite side, with a straight line passing through Each region is provided with at least one connection portion, and the number of connection portions in the second region is greater than the number of connection portions in the first region. Preferred (claim 5).

  In this case, the current distribution in the capacitor element can be made more uniform considering the balance with the current flowing through the main body of the bus bar. That is, due to the influence of the current flowing through the main body of the bus bar, the current path to the connection portion in the first region has a smaller inductance and the current flows than the current path to the connection portion in the second region. Cheap. Therefore, by increasing the number of connection portions in the second region where current is relatively difficult to flow than the number of connection portions in the first region where current is relatively easy to flow, the current flowing through both regions can be equalized. . As a result, the current distribution of the capacitor element can be effectively equalized.

  The main body of the bus bar extends in a direction orthogonal to the winding central axis, and the electrode surface is orthogonal to the extending direction of the main body of the bus bar and the electrode center point. The first region and the second region are divided into a first region on the side where the main body portion of the bus bar is extended and a second region on the opposite side, with a straight line passing through Each region is provided with at least one connection portion, and the total area of the connection portions in the second region is larger than the total area of the connection portions in the first region. (Claim 6).

  Also in this case, the current distribution in the capacitor element can be made more uniform in consideration of the balance with the current flowing through the main body of the bus bar. As described above, the current path to the connection part in the first region has a smaller inductance and the current flows more easily than the current path to the connection part in the second region. Therefore, by making the total area of the connection portion in the second region where current is relatively difficult to flow larger than the total area of the connection portion in the first region where current is relatively easy to flow, the current flowing through the two regions is equalized Can do. As a result, the current distribution of the capacitor element can be effectively equalized.

  The bus bar has a main body portion extending in a direction orthogonal to the winding center axis, and the bus bar is branched into three or more branches connected to the three or more connection portions, respectively. The main body of the bus bar has a straight line passing through the electrode center point and perpendicular to the extending direction of the main body of the bus bar. When divided into a first region which is an extended side and a second region which is the opposite side, at least one connection portion is provided in each of the first region and the second region. And the branch part connected to the connection part in the second region is preferably shorter than the branch part connected to the connection part in the first region ( Claim 7).

  Also in this case, the current distribution in the capacitor element can be made more uniform in consideration of the balance with the current flowing through the main body of the bus bar. As described above, the current path to the connection part in the first region has a smaller inductance and the current flows more easily than the current path to the connection part in the second region. Therefore, the branch portion connected to the connection portion in the second region where current is relatively difficult to flow is made shorter than the branch portion connected to the connection portion in the first region where current is relatively easy to flow. By reducing the resistance, the current flowing through both can be equalized. As a result, the current distribution of the capacitor element can be effectively equalized.

The capacitor module preferably includes a plurality of the capacitor elements, and the plurality of capacitor elements are connected in parallel by the pair of bus bars.
In this case, it is possible to easily configure a desired large-capacity capacitor module, to equalize the current distribution in each capacitor element, and to effectively suppress the heat generation amount.

Example 1
A capacitor module according to an embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the capacitor module 1 of this example is formed by winding a metallized film and having a pair of electrode surfaces 21p and 21n at both ends in the winding axis direction, and a pair of electrode surfaces 21p. , 21n, and a pair of bus bars 3p, 3n provided with external terminals 34p, 34n (FIGS. 7 and 8) at the other end.

The bus bars 3p and 3n are provided with six connection portions 4 with the electrode surfaces 21p and 21n of the capacitor element 2.
The winding center axis A of the capacitor element 2 exists inside the largest polygon 11 having the largest area among the polygons formed by connecting at least a part of the six connection parts 4 with straight lines. Thus, the connecting portion 4 is arranged.

  Here, the maximum polygon 11 will be described with reference to FIGS. For example, when six connecting portions 4 are annularly arranged as shown in FIG. 5A, polygons formed by connecting at least a part of connecting portions 4 with each other in a straight line are shown in FIG. Many patterns are conceivable including the patterns shown in (B) and (C). However, among the large number of patterns, as shown in FIG. 5B, the polygon (hexagon) connecting all the six connecting portions 4 becomes the maximum polygon 11 having the largest area.

  On the other hand, when the six connection portions 4 are arranged in the state shown in FIG. 6A, a polygon (hexagonal shape) connecting all the six connection portions 4 as shown in FIG. 6B. 6), the area of a polygon (pentagon) connecting five connecting portions 4 is larger as shown in FIG. 6C. Therefore, in the case of the arrangement of the connection portions 4 as shown in FIG. 6A, the polygon (pentagon) shown in FIG.

Although the connecting portion 4 actually has a size, the vertex of the polygon is strictly the center of the connecting portion 4.
In addition, the winding center axis A is an axis that becomes the winding center of the metallized film, but its exact position is the shape when the capacitor element 2 is viewed from the winding axis direction (see FIG. 4). The position that is the geometric center of gravity.

The capacitor element 2 is formed by winding a metallized film into a substantially elliptical column shape (FIG. 3). As shown in FIG. 1, an electrode member 210 made of metallicon is disposed on a pair of bottom surfaces of the substantially elliptical cylinder. The outer surface of the electrode member 210 is the electrode surfaces 21p and 21n. Therefore, the electrode surfaces 21p and 21n have a substantially elliptical shape (FIG. 4).
As shown in FIG. 1, one electrode surface 21p is connected to the positive bus bar 3p, and the other electrode surface 21n is connected to the negative bus bar 3n.

  As shown in FIGS. 1 and 3, each connecting portion 4 provided on one electrode surface 21p and each connecting portion 4 provided on the other electrode surface 21n are in the same straight line parallel to the winding center axis A. It is arranged on the line. That is, the six connection portions 4 on the electrode surface 21n are arranged at positions where the six connection portions 4 provided on the electrode surface 21p are orthogonally projected onto the other electrode surface 21n.

  Further, as shown in FIG. 4, the distance between the electrode center point B and the connection portion 4 on a straight line passing through the electrode center point B that is the intersection of the winding center axis A and the electrode surfaces 21 p and 21 n and the connection portion 4. The ratio of d1, d2, d3 and the distances e1, e2, e3 between the connecting portion 4 and the outer peripheral edge 211 of the electrode surfaces 21p, 21n is constant for all the connecting portions 4 provided on the electrode surfaces 21p, 21n. It is.

  It is preferable that 0.3 ≦ d1 / e1 = d2 / e2 = d3 / e3 ≦ 3, and more preferable that d1 / e1 = d2 / e2 = d3 / e3 = 2. Here, in FIG. 4, the connection part 4 that does not have d1, d2, d3, e1, e2, e3 between the electrode center point B and the outer peripheral edge 211 has the same relationship as described above.

  As described above, the ratio of the distances d1, d2, and d3 to the distances e1, e2, and e3 is constant for all the connection portions 4 provided on the electrode surfaces 21p and 21n, that is, d1 / e1 = Although it is desirable that d2 / e2 = d3 / e3, this ratio may be not constant. Even in this case, it is preferable that these ratios are in the range of 0.3 to 3.

  As shown in FIGS. 1 and 2, the bus bars 3p and 3n are extended in a direction orthogonal to the winding center axis A. The six connecting portions 4 are arranged so as to be line symmetric with respect to a straight line C that is parallel to the extending direction of the main body portion 30 of the bus bars 3p and 3n and passes through the electrode center point B. Here, the two connecting portions 4 are arranged on the straight line C.

  The bus bars 3p and 3n have six branch portions 31 that are branched so as to be connected to the six connection portions 4, respectively. The branch part 31 is formed of a single metal plate together with the main body part 30 of the bus bars 3p and 3n. That is, the branching portion 31 is formed by cutting and notching the metal plate and bending and deforming it as necessary.

The bus bar 3 has a hub portion 32 between the main body portion 30 and the branch portion 31, and the branch portions 31 are formed radially from the hub portion 32.
And the connection part 4 is formed by joining the front-end | tip of the branch part 31 to the predetermined position in the electrode surfaces 21p and 21n of the capacitor | condenser element 2 with solder | pewter. That is, the connection part 4 is comprised with solder.

  In addition, although it is preferable that the main-body part 30 and the hub part 32 of the bus-bar 3 are not in contact with the electrode surfaces 21p and 21n, you may contact. Even if they are in contact with each other, there is a large contact resistance in that portion, so that it is difficult for current to flow as compared with the connection portion 4. Therefore, the current does not change mainly through the connection portion 4.

  As shown in FIGS. 7 and 8, the capacitor module 1 of this example has a plurality of capacitor elements 2, and the plurality of capacitor elements 2 are connected in parallel by a pair of bus bars 3p and 3n. In this example, the capacitor module 1 is formed by connecting four capacitor elements 2 in parallel, and the capacitor elements 2 are arranged in two rows and two columns as shown in FIG.

  Each of the bus bars 3p and 3n includes a trunk portion 33 in which four main body portions 30 are connected to both sides in the width direction, and external terminals 34p and 34n provided at one end in the longitudinal direction of the trunk portion 33. As shown in FIG. 7, the external terminal 34 p of the bus bar 3 p on the positive electrode side rises at a right angle from the trunk portion 33 to the side opposite to the capacitor element 2. The external terminal 34n of the negative-side bus bar 3n rises obliquely from the trunk portion 33 toward the positive-side bus bar 3p and is arranged in parallel with the positive-side external terminal 34p.

As shown in FIG. 8, the capacitor element 2 is connected to each of the four main body portions 30 connected to the backbone portion 33 of the bus bars 3 p and 3 n via the branch portions 31.
Further, the extending direction of the main body 30 of the bus bars 3p and 3n described above refers to a direction from the hub portion 32 that is a connection portion with the branching portion 31 to the connection portion with the backbone portion 33 in the main body portion 30 ( 8 is an upward direction or a downward direction in FIG. 8, and is a left direction in FIGS.
Although not shown, the four capacitor elements 2 connected in parallel by the pair of bus bars 3p and 3n are resin-sealed in the case. The bus bars 3p and 3n are also resin-sealed except that the pair of external terminals 34p and 34n are exposed.

The capacitor module 1 of this example is incorporated in a power conversion device that performs power conversion by switching operations of a plurality of switching elements between a DC power source and an AC load, for example. The positive bus bar 3p is electrically connected to a positive terminal in the DC power source and a switching element on the high side. The negative electrode bus bar 3n is electrically connected to a negative electrode terminal in the DC power supply or a switching element on the low side.
That is, the external terminals 34p and 34n of the bus bars 3p and 3n are directly or indirectly connected to the DC power supply and the switching element.

  In this example, the example of the capacitor module 1 having four capacitor elements 2 is shown, but the number of capacitor elements 2 is not particularly limited. In addition, one capacitor element 2 can be provided. Further, the number of connection portions 4 on each electrode surface 21p, 21n is not limited to six, and may be three or more.

Next, the function and effect of this example will be described.
In the capacitor module 1, the bus bars 3 p and 3 n are provided with six connection portions 4 with the electrode surfaces 21 p and 21 n of the capacitor element 2. Therefore, the current is divided into six connection portions 4 from one (positive electrode side) bus bar 3p and then introduced into the capacitor element 2 through one (positive electrode side) electrode surface 21p. Then, the current flowing in the capacitor element 2 flows from the six connection portions 4 to the other (negative electrode side) bus bar 3n via the other (negative electrode side) electrode surface 21n.

  At this time, since the current tends to flow mainly in the shortest distance, the current path I in the capacitor element 2 is mainly formed from the connection portion 4 on one electrode surface 21p to the other electrode as shown in FIGS. Although it goes to the connection part 4 in the surface 21n, since six connection parts 4 are provided in each electrode surface 21p, 21n, at least six main current paths I are formed in the capacitor element 2. As a result, the current can be easily distributed over the entire capacitor element 2.

As shown in FIG. 4, the connecting portion 4 is arranged so that the winding center axis A of the capacitor element 2 exists inside the maximum polygon 11. By disposing the connection part 4 under such conditions, the distribution of the connection part 4 can be easily spread over the entire electrode surfaces 21p and 21n. That is, it becomes difficult to form the connection portion 4 at a biased position. Thereby, the current path I from the connection part 4 on the one electrode surface 21p to the connection part 4 on the other electrode surface 21n is easily formed over the entire capacitor element 2.
As a result, current concentration in the capacitor element 2 can be prevented, the amount of heat generated by the capacitor element 2 can be suppressed, and the temperature rise can be suppressed.

In particular, when the frequency of the current flowing through the capacitor element 2 is increased, the current is likely to flow linearly over the shortest distance. In this case as well, current concentration in the capacitor element 2 is suppressed, and the amount of heat generated by the capacitor element 2 is increased. Can be prevented from becoming too large. That is, it is possible to obtain the capacitor module 1 having excellent compatibility with the high frequency current.
Further, when the current frequency is increased, the impedance in the current path I is also increased, so that the amount of heat generation is increased. In this case as well, the current distribution is equalized as described above. The calorific value can be effectively suppressed.

  Each connecting portion 4 provided on one electrode surface 21p and each connecting portion 4 provided on the other electrode surface 21n are arranged on the same straight line parallel to the winding center axis A. Therefore, since the distance between a pair of connection parts 4 arranged on the same straight line can be made constant and shortest, the impedance of the current path I between each connection part 4 can be made constant and minimum. As a result, the current distribution in the capacitor element 2 can be made more uniform, and the amount of generated heat can be further suppressed.

  Further, as shown in FIG. 4, on the straight line passing through the electrode center point B and the connection part 4, the distances d1, d2, d3 between the electrode center point B and the connection part 4, and the connection part 4 and the electrode surfaces 21p, 21n. The ratios of the distances e1, e2, and e3 to the outer peripheral edge 211 are constant for all the connection portions 4 provided on the electrode surfaces 21p and 21n. Therefore, the arrangement of the connection portions 4 on the electrode surfaces 21p and 21n can be easily dispersed evenly over the entire electrode surfaces 21p and 21n. Therefore, it becomes easier to equalize the current distribution in the capacitor element 2.

  Further, as shown in FIG. 2, six connection portions 4 are arranged so as to be line-symmetric with respect to the straight line C. Therefore, it is possible to equalize the arrangement of the connection portions 4 on the electrode surfaces 21p and 21n, and to effectively prevent the current distribution in the capacitor element 2 from being biased.

  As described above, according to this example, it is possible to provide a capacitor module capable of equalizing the current distribution in the capacitor element and effectively suppressing the heat generation amount.

(Example 2)
As shown in FIG. 9, this example is arranged on the electrode surfaces 21p and 21n on both sides of the straight line D that is orthogonal to the extending direction of the main body 30 of the bus bars 3p and 3n and passes through the electrode center point B. In this example, the number of connecting parts 4 is asymmetric.

That is, the electrode surfaces 21p and 21n are divided into the first region 201 on the side where the main body portion 30 of the bus bars 3p and 3n extends and the second region 202 on the opposite side thereof with the straight line D as a boundary. Divide. At this time, the number of connection parts 4 in the second region 202 is larger than the number of connection parts 4 in the first region 201. In this example, three connection portions 4 are arranged in the first region 201, and four connection portions 4 are arranged in the second region 202.
Accordingly, the number of branching portions 31 is three for the first region 201 and four for the second region 202.
Others are the same as in the first embodiment.

  In the case of this example, the current distribution in the capacitor element 2 can be made more uniform in consideration of the balance with the current flowing through the main body 30 of the bus bars 3p and 3n. That is, due to the influence of the current flowing through the main body 30 of the bus bar, the current path to the connection part 4 in the first region 201 has a smaller inductance than the current path to the connection part 4 in the second region 202, Current flows easily. That is, the branch portion 31 extending from the hub portion 32 to the first region 201 has a smaller inductance and the current flows more easily than the branch portion 31 extending from the hub portion 32 to the second region 202.

Therefore, by increasing the number of connection portions 4 in the second region 202 where current is relatively difficult to flow than the number of connection portions 4 in the first region 201 where current is relatively easy to flow, the current flowing through both regions is equalized. can do. As a result, the current distribution of the capacitor element 2 can be effectively equalized.
In addition, the same effects as those of the first embodiment are obtained.

(Example 3)
As shown in FIG. 10, the present example is an example in which the total areas of the connecting portions 4 arranged on the electrode surfaces 21p and 21n are different in the first region 201 and the second region 202 shown in the second embodiment. is there.
That is, the total area in the second region 202 is larger than the total area of the connection portions 4 in the first region 201. Here, the total area of the connection part 4 in the first region 201 is a total sum of the areas of all the connection parts 4 arranged in the first region 201, and the total area of the connection part 4 in the second region 202. Is a total sum of the areas of all the connecting portions 4 arranged in the second region 202.

In this example, three connection portions 4 are arranged in each of the first region 201 and the second region 202. In addition, the area of one (center) connection part 40 of the three connection parts 4 in the second region 202 is made larger than that of the other five connection parts 4. Here, the area of the connection portion 4 refers to a bonding area between the solder as the connection portion 4 and the electrode surfaces 21p and 21n.
Further, the branch part 31 connected to the connection part 40 has an area of a cross section perpendicular to the current direction larger than the other branch parts 31.
Note that all of the connection portions 4 in the second region 202 may be equally large in area.
Others are the same as in the first embodiment.

Also in this example, the current distribution in the capacitor element 2 can be made more uniform in consideration of the balance with the current flowing through the main body 30 of the bus bars 3p and 3n. That is, by making the total area of the connection portion 4 in the second region 202 where current is relatively difficult to flow as described above larger than the total area of the connection portion 4 in the first region 201 where current is relatively easy to flow, The flowing current can be equalized. As a result, the current distribution of the capacitor element 2 can be effectively equalized.
Further, the same effect can be obtained by increasing the cross-sectional area of the branch part 31 connected to the connection part 40.
In addition, the same effects as those of the first embodiment are obtained.

Example 4
In this example, as shown in FIG. 11, the branch part 31 connected to the connection part 4 arranged in the second region 202 is changed from the branch part 31 connected to the connection part 4 arranged in the first area 201. This is a shortened example.
Further, as the length of the branch portion 31 is changed as described above, the position of the hub portion 32 is offset toward the second region 202 side. In other words, in the first to third embodiments, the center position of the hub portion 32 substantially coincides with the position of the winding center axis A (electrode center point B) of the capacitor element 2. The center position of the portion 32 is arranged at a position shifted from the winding center axis A (electrode center point B) to the second region 202 side.
Others are the same as in the first embodiment.

Also in this example, the current distribution in the capacitor element 2 can be made more uniform in consideration of the balance with the current flowing through the main body 30 of the bus bars 3p and 3n. That is, as described above, the branch portion 31 connected to the connection portion 4 in the second region 202 where current is relatively difficult to flow is used as the branch portion 31 connected to the connection portion 4 in the first region 201 where current is relatively easy to flow. By making the length shorter than that of the bent portion 31 and reducing its resistance, the current flowing through the both can be equalized. As a result, the current distribution of the capacitor element 2 can be effectively equalized.
In addition, the same effects as those of the first embodiment are obtained.

DESCRIPTION OF SYMBOLS 1 Capacitor module 11 Maximum polygon 2 Capacitor element 21p, 21n Electrode surface 3p, 3n Bus bar 30 Body part 31 Branch part 4 Connection part A Winding center axis

Claims (8)

A capacitor element formed by winding a metallized film and provided with a pair of electrode surfaces at both ends in the winding axis direction, and a pair of one end connected to the pair of electrode surfaces and an external terminal at the other end A capacitor module having a bus bar,
The bus bar is provided with three or more connecting portions with the electrode surface of the capacitor element,
Among the polygons formed by connecting at least a part of the three or more connecting portions with straight lines, the winding center axis of the capacitor element exists inside the largest polygon having the largest area. The capacitor module is characterized in that the connection portion is disposed on the capacitor module.   2. The capacitor module according to claim 1, wherein each of the connection portions provided on one of the electrode surfaces and each of the connection portions provided on the other electrode surface are parallel to the winding center axis. A capacitor module characterized by being arranged on a straight line.   3. The capacitor module according to claim 1, wherein the electrode center point and the connection portion are arranged on a straight line passing through the electrode center point that is an intersection of the winding center axis and the electrode surface and the connection portion. A capacitor module, wherein a ratio between a distance and a distance between the connecting portion and an outer peripheral edge of the electrode surface is constant for all the connecting portions provided on the electrode surface.   4. The capacitor module according to claim 1, wherein the main body portion of the bus bar extends in a direction orthogonal to the winding central axis, and the main body portion of the bus bar extends. 3. The capacitor module according to claim 1, wherein the three or more connecting portions are arranged so as to be line-symmetric with respect to a straight line parallel to the installation direction and passing through the electrode center point.   The capacitor module according to any one of claims 1 to 3, wherein the main body portion of the bus bar extends in a direction orthogonal to the winding center axis, and the electrode surface is connected to the bus bar. A first region which is a side where the main body portion of the bus bar extends from a straight line which is orthogonal to the extending direction of the main body portion and passes through the electrode center point, and a second region which is the opposite side. When divided into regions, each of the first region and the second region is provided with at least one connection portion, and more than the number of the connection portions in the first region. A capacitor module, wherein the number of the connecting portions in the second region is larger.   The capacitor module according to any one of claims 1 to 3, wherein the main body portion of the bus bar extends in a direction orthogonal to the winding center axis, and the electrode surface is connected to the bus bar. A first region which is a side where the main body portion of the bus bar extends from a straight line which is orthogonal to the extending direction of the main body portion and passes through the electrode center point, and a second region which is the opposite side. When divided into regions, the first region and the second region are each provided with at least one connection portion, and more than the total area of the connection portion in the first region, The capacitor module, wherein a total area of the connection portion in the second region is larger.   4. The capacitor module according to claim 1, wherein the bus bar main body extends in a direction orthogonal to the winding central axis, and the bus bars include the three or more bus bars. 3 or more branch parts branched so as to be connected to the connection parts, respectively, and the electrode surface is orthogonal to the extending direction of the body part of the bus bar and the electrode center point is The first area and the second area when divided into a first area on the side where the main body of the bus bar extends and a second area on the opposite side, with a straight line passing through as a boundary. Each of which is provided with at least one connecting portion and connected to the connecting portion in the second region rather than the branch portion connected to the connecting portion in the first region. The above branched part is shorter Capacitor module to be.   The capacitor module according to any one of claims 1 to 7, wherein a plurality of the capacitor elements are provided, and the plurality of capacitor elements are connected in parallel by the pair of bus bars.

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