JP7611516B2 - Capacitor - Google Patents

Description

The present invention relates to a capacitor.

Conventionally, there has been known a case-molded capacitor in which a bus bar is connected to each electrode provided on both end faces of a capacitor element, the capacitor element to which the bus bars are connected is housed in a case, and the case is filled with a filling resin (see, for example, Patent Document 1).

JP 2015-103777 A

When electricity is applied to the capacitor, the capacitor element generates heat. In a capacitor with the above configuration, the capacitor element is embedded in the filling resin, so heat is difficult to dissipate from the capacitor element. In particular, both end faces of the capacitor element can be covered by the parts of the bus bar that are connected to the electrodes, so heat generated from both end faces is easily dissipated by moving along the bus bar, which has good thermal conductivity. However, the peripheral surface of the capacitor element is rarely covered by the bus bar, so heat is difficult to dissipate.

In recent years, hybrid vehicles and electric vehicles have become widespread, and in these vehicles, a capacitor with the above configuration may be mounted in an inverter device for driving an electric motor. In this case, a large current is likely to flow from the power supply device to the inverter device, and therefore a large current is likely to flow to the capacitor element, which is likely to generate a large amount of heat. Therefore, if heat dissipation from the capacitor element is insufficient as described above, there is a risk that the capacitor element may suffer from problems such as thermal damage.

In view of such problems, the present invention aims to provide a capacitor that can improve heat dissipation from the capacitor element.

A first aspect of the present invention relates to a capacitor. The capacitor according to this aspect includes a capacitor element having a first electrode and a second electrode facing each other, a first bus bar and a second bus bar connected to the first electrode and the second electrode, respectively, a bottom surface portion, a first side surface portion and a second side surface portion rising from the bottom surface portion facing each other, and the capacitor element is housed in the case, and a filled resin filled in the case. Here, the capacitor element is housed in the case such that the second electrode faces the bottom surface portion of the case. The first bus bar includes a first electrode connection portion covering at least a part of the first electrode and connected to the first electrode, a first bus bar first extension portion extending from one end of the first electrode connection portion to the outside of the filled resin and having a first connection terminal connected to an external terminal on a portion exposed from the filled resin, and a first bus bar second extension portion extending from an end different from the one end of the first electrode connection portion along a circumferential surface of the capacitor element toward the bottom surface portion of the case. the second bus bar includes a second electrode connection portion that covers at least a portion of the second electrode and is connected to the second electrode, and a second bus bar first extension portion that extends from one end of the second electrode connection portion to the outside of the filled resin along a portion of the circumferential surface of the capacitor element that faces away from the portion of the circumferential surface along which the first bus bar second extension portion runs, and has a second connection terminal connected to an external terminal on a portion exposed from the filled resin. A connection terminal that extends to the outside of the filled resin and is connected to an external terminal is not connected to the first bus bar second extension portion, and the first bus bar second extension portion is aligned along the second side surface portion of the case.
A second aspect of the present invention relates to a capacitor. The capacitor according to this aspect includes a capacitor element having a first electrode and a second electrode facing each other, a first bus bar and a second bus bar connected to the first electrode and the second electrode, respectively, a case having a bottom surface and a first side surface and a second side surface rising from the bottom surface and facing each other, the case housing the capacitor element, and a filling resin filled in the case. Here, the capacitor element is housed in the case such that the first electrode and the second electrode face the first side surface and the second side surface of the case, respectively. The first bus bar includes a first electrode connection portion covering at least a portion of the first electrode and connected to the first electrode, a first bus bar first extension portion extending from one end of the first electrode connection portion to the outside of the filled resin and having a first connection terminal connected to an external terminal at a portion exposed from the filled resin, and a first bus bar second extension portion extending from an end different from the one end of the first electrode connection portion along a portion of the circumferential surface of the capacitor element facing the bottom surface portion. The second bus bar includes a second electrode connection portion covering at least a portion of the second electrode and connected to the second electrode, and a second bus bar first extension portion extending from one end of the second electrode connection portion to the outside of the filled resin and having a second connection terminal connected to an external terminal at a portion exposed from the filled resin. Three or more capacitor elements including the capacitor element are arranged in a row inside the case. The first electrode connection portion has a plate shape parallel to the surfaces of the first electrodes of the three or more capacitor elements, and the first busbar second extension portion extends from an end of the first electrode connection portion opposite the bottom portion in a direction perpendicular to the direction in which the three or more capacitor elements are arranged, along a portion of the circumferential surface of all of the three or more capacitor elements that faces the bottom portion.

The present invention provides a capacitor that can improve heat dissipation from the capacitor element.

The effects and significance of the present invention will become clearer from the description of the embodiment shown below. However, the embodiment shown below is merely an example of how the present invention can be put into practice, and the present invention is in no way limited to the embodiment described below.

FIG. 1( a ) is a perspective view of a film capacitor according to an embodiment, and FIG. 1( b ) is a side cross-sectional view of the film capacitor according to the embodiment from which a filling resin is omitted. 2(a) and 2(b) are perspective views of a capacitor element unit according to an embodiment as viewed from above the front and below the rear, respectively. 3(a) and (b) are perspective views of a first bus bar and a second bus bar, respectively, according to an embodiment. FIG. 4(a) is a perspective view of the case according to the embodiment as viewed from above and at the front, and FIG. 4(b) is a perspective view of the case according to the embodiment as viewed from below and at the front. 5(a) and (b) are side cross-sectional views of a film capacitor according to a modified example in which the filling resin is omitted. FIG. 6 is a side cross-sectional view of a film capacitor according to a modified example in which the filling resin is omitted. 7(a) is a side cross-sectional view of a film capacitor according to another embodiment, and Figs. 7(b) and 7(c) are a front view and a rear view, respectively, of a capacitor element unit according to another embodiment. 8(a) and (b) are side views of a capacitor element unit according to a modified example of the other embodiment.

Below, a film capacitor 1, which is one embodiment of a capacitor of the present invention, will be described with reference to the figures. For convenience, each figure is appropriately indicated with the directions of front/back, left/right, and up/down. Note that the directions shown in the figures indicate only relative directions of the film capacitor 1, and do not indicate absolute directions. Also, for convenience of explanation, some configurations may be given names that correspond to the directions shown in the figures, such as the "bottom portion" and "front side portion."

In this embodiment, the film capacitor 1 corresponds to the "capacitor" described in the claims. The first electrode 110 and the second electrode 120 correspond to the "electrodes" described in the claims. The electrode terminal portions 210, 310 correspond to the "electrode connection portion" described in the claims. The terminal forming portions 220, 320 correspond to the "first extension portion" described in the claims. The heat dissipation portion 330 corresponds to the "second extension portion" described in the claims.

However, the above description is intended merely to match the configuration of the claims with the configuration of the embodiments, and the above correspondence does not in any way limit the invention described in the claims to the configuration of the embodiments.

Figure 1(a) is an oblique view of a film capacitor 1, and Figure 1(b) is a side cross-sectional view of the film capacitor 1 with the filling resin 500 omitted.

1(a) and (b), the film capacitor 1 comprises five capacitor elements 100, a first bus bar 200, a second bus bar 300, a case 400, and filled resin 500. The five capacitor elements 100, the first bus bar 200, and the second bus bar 300 are assembled together to form a capacitor element unit 10. The capacitor element unit 10 is housed in the case 400, and the case 400 is filled with filled resin 500. The filled resin 500 is a thermosetting resin, for example, epoxy resin. The portion of the capacitor element unit 10 buried in the filled resin 500 is protected from moisture and impact by the case 400 and the filled resin 500.

2(a) and (b) are perspective views of the capacitor element unit 10 as viewed from the upper front and lower rear, respectively. Figures 3(a) and (b) are perspective views of the first bus bar 200 and the second bus bar 300, respectively.

The five capacitor elements 100 are formed by stacking two metallized films, each of which has aluminum vapor-deposited on a dielectric film, rolling or laminating the stacked metallized films, and pressing them into a flat shape. The capacitor elements 100 have a shape similar to a flat, oval cylinder. The capacitor elements 100 have a first electrode 110 formed on one end face 101 by spraying a metal such as zinc, and a second electrode 120 formed on the other end face 102 by spraying a metal such as zinc.

In the present embodiment, the capacitor element 100 is formed from a metallized film in which aluminum is vapor-deposited onto a dielectric film, but it may also be formed from a metallized film in which other metals, such as zinc or magnesium, are vapor-deposited. Alternatively, the capacitor element 100 may be formed from a metallized film in which a plurality of these metals are vapor-deposited, or from a metallized film in which an alloy of these metals is vapor-deposited.

In the capacitor element unit 10, the five capacitor elements 100 are arranged in a row in the left-right direction such that one end face 101, i.e., the first electrode 110, faces upward and the other end face 102, i.e., the second electrode 120, faces downward, and the peripheral faces 103 are adjacent to each other. A first bus bar 200 and a second bus bar 300 are electrically connected to the first electrodes 110 and second electrodes 120 of the five capacitor elements 100, respectively.

The first busbar 200 is formed by appropriately cutting and bending a conductive material, for example, a copper plate, and has a configuration in which the electrode terminal portion 210 and the terminal forming portion 220 are integrated together. In this embodiment, the first busbar 200 is an N-pole busbar.

The electrode terminal portion 210 has a rectangular plate shape and contacts the first electrodes 110 of the five capacitor elements 100 so as to cover almost the entire first electrodes 110 from above. That is, the front and rear ends of the electrode terminal portion 210 extend to the front and rear ends of the five capacitor elements 100. In addition, the left end of the electrode terminal portion 210 extends to the vicinity of the left end of the leftmost capacitor element 100, and the right end of the electrode terminal portion 210 extends to the vicinity of the right end of the rightmost capacitor element 100.

Five openings 211 are formed in the electrode terminal portion 210, aligned in the left-right direction, to correspond to each first electrode 110. A pair of connection pins 212 is formed at the rear edge of each opening 211. A corresponding pair of connection pins 212 contacts each first electrode 110 and is joined by a joining method such as soldering. The thickness of each connection pin 212 is made smaller than the thickness of other parts of the electrode terminal portion 210, so that the connection pins 212 are less likely to absorb heat, making it easier to perform soldering, etc.

The terminal forming portion 220 has the same left-right width as the electrode terminal portion 210, and extends straight up from the rear end of the electrode terminal portion 210, then bends and extends rearward at a slight upward incline. Three connection terminals 221 are formed at the tip of the terminal forming portion 220. Each connection terminal 221 extends rearward while maintaining the same angle as the tip of the terminal forming portion 220, and then has a shape in which the tip is bent upward. A circular mounting hole 221a is formed at the tip of each connection terminal 221.

The portion of the terminal forming portion 220 other than the three connection terminals 221 becomes a relay portion 222 connecting the electrode terminal portion 210 and the three connection terminals 221.

The first busbar 200 has four U-shaped notches 231 aligned in the left-right direction at the front end of the electrode terminal portion 210.

The second busbar 300 is formed by appropriately cutting and bending a conductive material, for example, a copper plate, and has a configuration in which an electrode terminal portion 310, a terminal forming portion 320, and a heat dissipation portion 330 are integrated together. In this embodiment, the second busbar 300 is a P-pole busbar.

The electrode terminal portion 310 has a rectangular plate shape and contacts the second electrodes 120 of the five capacitor elements 100 so as to cover almost the entire second electrodes 120 from below. That is, the front and rear ends of the electrode terminal portion 310 extend to the front and rear ends of the five capacitor elements 100. In addition, the left end of the electrode terminal portion 310 extends to the vicinity of the left end of the leftmost capacitor element 100, and the right end of the electrode terminal portion 310 extends to the vicinity of the right end of the rightmost capacitor element 100.

Five openings 311 are formed in the electrode terminal portion 310, aligned in the left-right direction, to correspond to each second electrode 120. A pair of connection pins 312 is formed at the rear edge of each opening 311. A corresponding pair of connection pins 312 contacts each second electrode 120 and is joined by a joining method such as soldering. The thickness of each connection pin 312 is made smaller than the thickness of other parts of the electrode terminal portion 310, so that the connection pins 312 are less likely to absorb heat, making it easier to perform soldering, etc.

The terminal forming portion 320 has the same left-right width as the electrode terminal portion 310, extends upward from the rear end of the electrode terminal portion 310 along the rear peripheral surface 103 of the five capacitor elements 100, bends forward above the peripheral surface 103, extends slightly upward, then bends and extends backward at a slight upward incline. Three connection terminals 321 are formed at the tip of the terminal forming portion 320. Each connection terminal 321 has a shape that extends backward while maintaining the same angle as the tip of the terminal forming portion 320, and then bends upward. A circular mounting hole 321a is formed at the tip of each connection terminal 321. Each connection terminal 321 is located to the right of each connection terminal 221 of the first bus bar 200.

The portion of the terminal forming portion 320 other than the three connection terminals 321 becomes a relay portion 322 connecting the electrode terminal portion 310 and the three connection terminals 321.

The heat dissipation section 330 has a rectangular plate shape with the same width on the left and right as the electrode terminal section 310, and extends upward from the front end of the electrode terminal section 310 along the front peripheral surface 103 of the five capacitor elements 100. The front end of the electrode terminal section 310 is an end in a direction perpendicular to the direction in which the five capacitor elements 100 are arranged (an end edge along the arrangement direction), and is an end different from the end (rear end) from which the terminal forming section 320 extends.

The heat dissipation section 330 covers more than half, more specifically, approximately two-thirds, of the peripheral surface 103 of the five capacitor elements 100 from the end surface 102 side, i.e., the second electrode 120 side, in the thickness direction of the capacitor element 100 (the direction in which the two end surfaces 101, 102 are aligned) (see FIG. 1(b)). As a result, when the peripheral surface 103 of the capacitor element 100 is equally divided into three regions in the thickness direction, the end surface 101 side, the center, and the end surface 102 side, the center region is covered by the heat dissipation section 330. Furthermore, the heat dissipation section 330 covers the entire peripheral surface 103 of the three inner capacitor elements 100 in the direction in which the capacitor elements 100 are aligned, and covers more than half, more specifically, approximately two-thirds, of the peripheral surface 103 of the capacitor elements 100 on both the left and right ends.

The heat dissipation portion 330 is adjacent to the peripheral surface 103 of each capacitor element 100 with a small gap (see FIG. 1(b)). The heat dissipation portion 330 may be adjacent to the peripheral surface 103 of each capacitor element 100 in contact therewith.

A predetermined distance L is provided between the position of the tip of the heat dissipation portion 330 and the position of the first electrode 110, which is equal to or greater than the spatial distance (insulation distance) required for insulation (see FIG. 1(b)). This ensures insulation between the second bus bar 300 and the first electrode 110. Note that it is desirable to set the distance L close to the spatial distance so that a larger portion of the peripheral surface 103 of the capacitor element 100 is covered by the heat dissipation portion 330.

In the second busbar 300, four circular openings 341 aligned in the left-right direction are formed in the relay portion 322 of the terminal forming portion 320. In addition, in the second busbar 300, four oval openings 342 aligned in the left-right direction are formed in the corners between the electrode terminal portion 310 and the terminal forming portion 320, and four square openings 343 aligned in the left-right direction are formed in the corners between the electrode terminal portion 310 and the heat dissipation portion 330. In addition, in the second busbar 300, square fitting pieces 344 are formed at the left and right ends of the relay portion 322.

In the capacitor element unit 10, the relay portion 222 of the first bus bar 200 and the upper portion of the relay portion 322 of the second bus bar 300 overlap in the thickness direction. This is expected to reduce the ESL (equivalent series inductance) in the capacitor element unit 10.

A first insulating sheet 610 is sandwiched between the overlapping portion of the relay portion 222 of the first busbar 200 and the relay portion 322 of the second busbar 300. The relay portion 222 of the first busbar 200 is covered from above with three second insulating sheets 620. The relay portion 322 of the second busbar 300 is covered from below with a third insulating sheet 630.

The first insulating sheet 610, the second insulating sheet 620, and the third insulating sheet 630 are formed from insulating paper or a resin material having electrical insulation properties such as acrylic or silicone. The first insulating sheet 610 ensures insulation between the first bus bar 200 and the second bus bar 300, and between the second bus bar 300 and the first electrode 110 of the capacitor element 100. In addition, the second insulating sheet 620 and the third insulating sheet 630 ensure insulation between the first bus bar 200 and the second bus bar 300 and the surrounding electrical components when the film capacitor 1 is installed in an external device such as an inverter device.

Figure 4(a) is an oblique view of case 400 seen from above the front, and Figure 4(b) is an oblique view of case 400 seen from below the front.

The case 400 is made of resin, for example, polyphenylene sulfide (PPS), which is a thermoplastic resin. The case 400 is formed in a substantially rectangular box shape, and has a bottom surface 401, a front side surface 402, a rear side surface 403, a left side surface 404, and a right side surface 405 that rise from the bottom surface 401, and is open at the top.

First mounting tabs 410 are provided on the left and right ends of the left side surface portion 404, the right side surface portion 405 and the bottom surface portion 401. An insertion hole 411 is formed in each first mounting tab 410. A metal collar 412 is fitted into the insertion hole 411 to increase the strength of the hole. Second mounting tabs 420 are provided in the center and on the left and right ends of the front end of the bottom surface portion 401. Metal nuts 421 are embedded in the second mounting tabs 420. These first mounting tabs 410 and second mounting tabs 420 are used when the film capacitor 1 is fixed to the installation portion of an external device.

Inside the case 400, a fitting groove 430 is formed by a pair of ribs at the lower rear ends of the left side surface portion 404 and the right side surface portion 405, and extends in the vertical direction. The width of the fitting groove 430 is approximately equal to the thickness of the fitting piece 344 of the second bus bar 300. Note that only the left fitting groove 430 is shown in Figure 4(a).

When the film capacitor 1 is assembled, the capacitor element unit 10 is housed in the case 400 as shown in FIG. 1B. At this time, the left and right fitting pieces 344 of the second bus bar 300 are fitted into the left and right fitting grooves 430 of the case 400. This prevents the capacitor element unit 10 from tilting in the front-back, left-right, and up-down directions relative to the case 400. The five capacitor elements 100 are arranged such that one end face 101, i.e., the first electrode 110 and the electrode terminal portion 210 of the first bus bar 200, faces the opening 400a of the case 400, and the other end face 102, i.e., the second electrode 120 and the electrode terminal portion 310 of the second bus bar 300, faces the bottom surface 401 of the case 400. The relay portion 322 of the terminal forming portion 320 of the second bus bar 300 is close to the inner wall surface of the rear side surface portion 403 of the case 400 with a small gap. Moreover, heat dissipation portion 330 of second bus bar 300 is arranged along the inner wall surface of front side surface portion 402 of case 400 and is close to the inner wall surface with a small gap therebetween. Note that relay portion 322 and heat dissipation portion 330 may be configured to contact the inner wall surface.

Filling resin 500 in a liquid phase is injected into case 400. At this time, filling resin 500 passes through notch 231 of first bus bar 200 and openings 341, 342, 343 of second bus bar 300, which makes it easier for filling resin 500 to spread throughout the entire interior of case 400. When filling resin 500 fills case 400 up to the vicinity of opening 400a of case 400 and injection of filling resin 500 is completed, case 400 is heated. This causes filling resin 500 in case 400 to harden.

1(a), the film capacitor 1 is completed. In the capacitor element unit 10, the terminal forming portion 220 of the first bus bar 200 extends out of the filled resin 500, and the three connection terminals 221 are exposed from the filled resin 500. Similarly, the terminal forming portion 320 of the second bus bar 300 extends out of the filled resin 500, and the three connection terminals 321 are exposed from the filled resin 500.

The film capacitor 1 may be mounted, for example, on an inverter device for driving an electric motor in an electric vehicle. The inverter device is supplied with DC power from a power supply device (battery). The inverter device includes an inverter circuit including an IGBT (insulated gate bipolar transistor), converts the DC power into three-phase AC power, and supplies it to the electric motor. External terminals (not shown) connected to the power supply device corresponding to the connection terminal 221 at the right end of the first bus bar 200 and the connection terminal 321 at the right end of the second bus bar 300 are connected by screwing using the mounting holes 221a, 321a. In addition, external terminals (not shown) connected to the inverter circuit corresponding to the three first connection terminals 220 of the first bus bar 200 and the three first connection terminals 320 of the second bus bar 300 are connected by screwing using the mounting holes 221a, 321a. The connection terminal 221 at the right end of the first bus bar 200 and the connection terminal 321 at the right end of the second bus bar 300 are connected to external terminals of both the power supply device and the inverter device.

In order to enhance the heat dissipation effect of the film capacitor 1 installed in the inverter device, a cooler 2 is attached to the rear side portion 403 of the case 400 (see FIG. 1(b)). As the cooler 2, for example, a water-cooled cooler can be used.

When the inverter device operates and electricity is applied to the film capacitor 1, the five capacitor elements 100 generate heat. Of the five capacitor elements 100, the three capacitor elements 100 located inside the capacitor elements 100 at the left and right ends, particularly the central capacitor element 100, tend to become hotter due to the heat generated.

The heat generated from the end face 101 of each capacitor element 100 is transferred to the electrode terminal portion 210 of the first bus bar 200, and most of the heat moves from the electrode terminal portion 210 to the relay portion 222 of the terminal forming portion 220 and is released to the outside from the portion of the relay portion 222 exposed from the filling resin 500. A portion of the heat transferred to the electrode terminal portion 210 can also be released to the outside from the opening 400a of the case 400 via the filling resin 500 above the electrode terminal portion 210.

The heat generated from the end face 102, the front peripheral surface 103, and the rear peripheral surface 103 of each capacitor element 100 is transferred to the electrode terminal portion 310, the heat dissipation portion 330, and the relay portion 322 of the terminal forming portion 320 of the second bus bar 300, respectively. In the second bus bar 300, the relay portion 322 adjacent to the rear side portion 403 of the case 400 is cooled, i.e., heat is absorbed, by the cooler 2. Therefore, the heat transferred to the relay portion 322 is released to the cooler 2, and most of the heat transferred to the electrode terminal portion 310 and the heat dissipation portion 330 moves to the relay portion 322 and is released to the cooler 2. A portion of the heat transferred to the electrode terminal portion 310 and the heat dissipation portion moves to the bottom portion 401 and the front side portion 402, respectively, and can also be released to the outside from the bottom portion 401 and the front side portion 402.

In this way, heat is dissipated from the five capacitor elements 100, making these capacitor elements 100 less likely to become overheated.

In addition, when the first mounting tab 410 and the second mounting tab 420 are not provided on the bottom surface portion 401 of the case 400, the cooler 2 may be attached to the bottom surface portion 401. In this case, the electrode terminal portion 310 of the second bus bar 300 is cooled by the cooler 2, and the heat transferred to the heat dissipation portion 330 and the relay portion 322 moves to the electrode terminal portion 310.

In addition, there are cases where the cooler 2 is not attached to the film capacitor 1. In this case, most of the heat transferred to the electrode terminal portion 310, the heat dissipation portion 330, and the relay portion 322 of the second busbar 300 is released to the outside from the portion of the relay portion 322 exposed from the filling resin 500, and the remaining heat is released to the outside from the bottom portion 401, the front side portion 402, and the rear side portion 403 of the case 400.

<Effects of the embodiment>
As described above, according to the present embodiment, the following effects are achieved.

The film capacitor 1 includes a first bus bar 200 and a second bus bar 300 which cover the electrodes 110, 120 and include electrode terminal portions 210, 310 connected to the electrodes 110, 120, and terminal forming portions 220, 320 which extend outward from the rear ends of the electrode terminal portions 210, 310 from the filled resin 500 and have connection terminals 221, 321 connected to external terminals at the portions exposed from the filled resin 500, and the second bus bar 300 is configured to have a heat dissipation portion 330 which extends from the front end of the electrode terminal portion 310 along the peripheral surface 103 of the capacitor element 100.

According to this configuration, by providing a heat dissipation section 330 on the second busbar 300, heat is easily dissipated not only from both end faces 101, 102 of the capacitor element 100 but also from the peripheral surface 103, so that the capacitor element 100 can be prevented from becoming too hot when current is applied to the film capacitor 1, and thermal damage to the capacitor element 100 can be prevented.

In addition, the film capacitor 1 is configured so that the heat dissipation portion 330 is aligned along the inner wall surface of the case 400.

With this configuration, heat transferred to the heat dissipation section 330 is easily transferred to the inner wall surface and easily dissipated to the outside of the case 400 via the inner wall surface, making it even easier for heat to be dissipated from the capacitor element 100.

Furthermore, the film capacitor 1 is configured such that the heat dissipation portion 330 extends from the front end, which is the end of the electrode connection portion 310 in a direction perpendicular to the direction in which the capacitor elements 100 are arranged.

With this configuration, the peripheral surface 103 of the inner capacitor element 100, which is sandwiched between the capacitor elements 100 at the left and right ends and therefore is prone to becoming hot, can be covered with the heat dissipation portion 330, thereby improving the heat dissipation properties of the inner capacitor element 100 and preventing it from becoming too hot.

Furthermore, the film capacitor 1 is configured such that a predetermined distance L is provided between the position of the tip of the heat dissipation portion 330 of the second bus bar 300 and the position of the first electrode 110 to which the first bus bar 200 is connected.

With this configuration, the heat dissipation properties of the capacitor element 100 can be improved while ensuring insulation between the second bus bar 300 and the first electrode 110.

Furthermore, the film capacitor 1 is configured such that the capacitor element 100 is accommodated within the case 400 such that the second electrode 120 to which the second bus bar 300 is connected faces the bottom surface portion 401 of the case 400, the terminal forming portion 320 of the second bus bar 300 extends along the peripheral surface 103 of the capacitor element 100 and is then exposed from the filled resin 500, and the heat dissipation portion 330 is provided on the second bus bar 300 of the first bus bar 200 and the second bus bar 300.

With this configuration, when the film capacitor 1 is installed in an external device, the cooler 2 can be attached to the bottom surface 401 of the case 400 or the side surface (rear side surface 403) facing the portion along the peripheral surface 103 of the terminal forming portion 320 to cool (absorb heat) the second bus bar 300, and the heat dissipation portion 330 is provided on the side of the second bus bar 300 that can be cooled by the cooler 2, so that the heat transferred to the heat dissipation portion 330 is effectively dissipated. As a result, heat can be effectively dissipated from the peripheral surface 103 of the capacitor element 100, so that the capacitor element 100 is even less likely to become hot.

<Example of change>
Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and application examples of the present invention can be modified in various ways in addition to the above embodiment.

For example, in the above embodiment, the first busbar 200 is not provided with a heat dissipation portion, and the second busbar 300 is provided with the heat dissipation portion 330. However, as shown in FIG. 5(a), the second busbar 300 may not be provided with the heat dissipation portion 330, and the first busbar 200 may be provided with a heat dissipation portion 230 similar to the heat dissipation portion 330. The heat dissipation portion 230 extends downward from the front end of the electrode terminal portion 210 of the first busbar 200 along the peripheral surface 103 of the capacitor element 100, and a distance L for insulation is provided between the position of the tip of the heat dissipation portion and the position of the second electrode 120.

Furthermore, as shown in FIG. 5(b), the first bus bar 200 and the second bus bar 300 are each provided with a heat dissipation section 230, 330. In this configuration, in the thickness direction of the capacitor element 100, more than half of the peripheral surface 103 of the capacitor element 100 is covered by both heat dissipation sections 230, 330. In addition, the tips of both heat dissipation sections 230, 330 overlap the central region of the peripheral surface 103, and a part of the central region is covered by the heat dissipation sections 230, 330. Furthermore, a distance L for insulation is provided between the tips of both heat dissipation sections 230, 330, and insulation between the first bus bar 200 and the second bus bar 300 is ensured. Note that the lengths of both heat dissipation sections 230, 330 in the thickness direction of the capacitor element 100 may be the same or different.

In addition, when the heat dissipation effect when using the cooler 2 is taken into consideration, it is more preferable to provide the heat dissipation section 330 on the second bus bar 300 as in this embodiment than the configuration in Fig. 5(a). In addition, when the configuration in Fig. 5(b) is adopted, by attaching the cooler 2 to the front side section 402 of the case 400, both the first bus bar 200 and the second bus bar 300 can be cooled by the cooler 2.

Furthermore, in the above embodiment, a predetermined distance L is provided between the position of the tip of the heat dissipation portion 330 of the second bus bar 300 and the first electrode 110 of the capacitor element 100. However, as shown in FIG. 6, the tip of the heat dissipation portion 330 may be extended to the position of the first electrode 110, that is, in the thickness direction of the capacitor element 100, the entire peripheral surface 103 may be covered with the heat dissipation portion 330, and the fourth insulating sheet 640 may be sandwiched between the tip portion of the heat dissipation portion 330 and the capacitor element 100. In this configuration, the fourth insulating sheet 640 ensures insulation between the second bus bar 300 and the first electrode 110. In this configuration, while a new fourth insulating sheet 640 is required, the area of the peripheral surface 103 of the capacitor element 100 covered by the heat dissipation portion 330 becomes larger, and heat dissipation from the peripheral surface 103 may be improved.

In addition, in the configuration of Figure 5 (a), similar to the configuration of Figure 6, a configuration may be adopted in which the tip of the heat dissipation portion 230 is extended to the position of the second electrode 120, and a fourth insulating sheet 640 is sandwiched between the tip portion of the heat dissipation portion 230 and the capacitor element 100.

<Other embodiments>
Fig. 7(a) is a side cross-sectional view of a film capacitor 1A according to another embodiment, and Figs. 7(b) and 7(c) are a front view and a rear view, respectively, of a capacitor element unit 20 according to another embodiment.

In this embodiment, the film capacitor 1A corresponds to the "capacitor" described in the claims. The first electrode 711 and the second electrode 712 correspond to the "electrodes" described in the claims. The electrode terminal portions 721, 731 correspond to the "electrode connection portion" described in the claims. The terminal forming portions 722, 732 correspond to the "first extension portion" described in the claims. The heat dissipation portion 723 corresponds to the "second extension portion" described in the claims.

The film capacitor 1A includes a capacitor element unit 20 in which a first bus bar 720 and a second bus bar 730 are connected to five capacitor elements 710, a rectangular parallelepiped case 740 in which the capacitor element unit 20 is housed, and a filling resin 750 that is filled in the case 740. The case 740 is made of a resin such as PPS, and the filling resin 750 is made of a thermosetting resin such as epoxy resin. The capacitor element unit 20 is housed in the case 740 such that the first electrodes 711 and second electrodes 712 of the five capacitor elements 710 face the front side portion 741 and rear side portion 742 of the case 740, respectively.

The first busbar 720 is formed by appropriately cutting and bending a conductive material, such as a copper plate, and has a configuration in which an electrode terminal portion 721, a terminal forming portion 722, and a heat dissipation portion 723 are integrated together.

The electrode terminal portion 721 has a rectangular plate shape and contacts the first electrodes 711 of the five capacitor elements 710 so as to cover the entire first electrodes 711 from the front. Five openings 724 aligned in the left-right direction are formed in the electrode terminal portion 721 to correspond to each of the first electrodes 710. A pair of connection pins 725 is formed on the upper edge of each opening 724. A corresponding pair of connection pins 725 contacts each first electrode 711 and is joined by a joining method such as soldering.

The terminal forming portion 722 extends rearward from the upper end of the electrode terminal portion 721, then bends and extends upward. Three square-shaped connection terminals 726 are formed at the tip of the terminal forming portion 722. A circular mounting hole 726a is formed at the tip of each connection terminal 726.

The heat dissipation portion 723 has a rectangular plate shape with the same width on the left and right as the electrode terminal portion 721, and extends rearward from the lower end of the electrode terminal portion 721 along the lower peripheral surface 710a of the five capacitor elements 710. The lower end of the electrode terminal portion 721 is an end in a direction perpendicular to the direction in which the five capacitor elements 710 are arranged, and is an end different from the end (upper end) from which the terminal forming portion 722 extends.

The heat dissipation portion 723 covers more than half, more specifically, approximately two-thirds, of the peripheral surfaces 710a of the five capacitor elements 710 from the first electrode 711 side in the thickness direction of the capacitor element 100. The heat dissipation portion 723 also covers the entire peripheral surfaces 710a of the five capacitor elements 710 in the direction in which the capacitor elements 710 are arranged. Furthermore, the heat dissipation portion 723 contacts the peripheral surface 103 of each capacitor element 710.

A predetermined distance L, which is equal to or greater than the spatial distance (insulation distance) required for insulation, is provided between the tip of the heat dissipation portion 723 and the second electrode 712. This ensures insulation between the first bus bar 720 and the second electrode 712.

The heat dissipation section 723 is aligned along the inner wall surface of the front side portion 741 of the case 740 and is close to the inner wall surface with a small gap.

The second busbar 730 is formed by appropriately cutting and bending a conductive material, such as a copper plate, and has a configuration in which an electrode terminal portion 731 and a terminal forming portion 732 are integrated together.

The electrode terminal portion 731 has a rectangular plate shape and contacts the second electrodes 712 of the five capacitor elements 710 so as to cover the entire second electrodes 712 from behind. Five openings 733 are formed in the electrode terminal portion 731, aligned in the left-right direction, to correspond to each second electrode 712. A pair of connection pins 734 is formed on the upper edge of each opening 733. A corresponding pair of connection pins 734 contacts each second electrode 712 and is joined by a joining method such as soldering.

The terminal forming portion 732 extends upward from the upper end of the electrode terminal portion 731. Three square-shaped connection terminals 735 are formed at the tip of the terminal forming portion 732. A circular mounting hole 735a is formed at the tip of each connection terminal 735. Each connection terminal 735 is located to the left of each connection terminal 726 of the first bus bar 720.

An insulating sheet 760 is sandwiched between the overlapping portion of the terminal forming portion 722 of the first bus bar 720 and the terminal forming portion 732 of the second bus bar 730. This ensures insulation between the first bus bar 200 and the second bus bar 300.

The film capacitor 1A is installed in an external device such as an inverter device. At this time, the cooler 2 is attached to the front side portion 741 of the case 740 of the film capacitor 1A.

The film capacitor 1A of this embodiment also achieves the same effects as the film capacitor 1 of the above embodiment.

In the film capacitor 1A of the present embodiment, as shown in Fig. 8(a), the first bus bar 720 may not be provided with a heat dissipation portion 723, and the second bus bar 730 may be provided with a heat dissipation portion 736 similar to the heat dissipation portion 723. Also, as shown in Fig. 8(b), the first bus bar 720 and the second bus bar 730 may both be provided with heat dissipation portions 723 and 736, respectively.

Furthermore, in the film capacitor 1A of this embodiment, as shown in Figure 6, the tip of the heat dissipation portion 723 may be extended to the position of the second electrode 712, and an insulating sheet may be sandwiched between the tip portion of the heat dissipation portion 723 and the capacitor element 710.

<Other changes>
In the above embodiment, the peripheral surfaces 103 of all five capacitor elements 100 are covered by the heat dissipation portion 330. However, the capacitor elements 100 at both the left and right ends are less likely to become hot than the three inner capacitor elements 100. Therefore, when the heat dissipation properties of the capacitor elements 100 at both the left and right ends are good, a configuration in which only the peripheral surfaces 103 of the three inner capacitor elements 100 are covered by the heat dissipation portion 330 may be adopted. On the other hand, when the heat dissipation properties of the capacitor elements 100 at both the left and right ends are poor, the second bus bar 300 may be provided with a heat dissipation portion that extends from the left end of the electrode terminal portion 310 so as to follow the left peripheral surface 103 of the left-end capacitor element 100 and a heat dissipation portion that extends from the right end of the electrode terminal portion 310 so as to follow the right peripheral surface 103 of the right-end capacitor element 100 in addition to the heat dissipation portion 330 that extends from the front end of the electrode terminal portion 310. The above two modifications can also be applied to the case where the heat dissipation portion 230 is provided on the first bus bar 200 .

In addition, in the above embodiment, the first bus bar 200 and the second bus bar 300 are provided with three connection terminal portions 221, 321, but the number of connection terminals 221, 321 may be changed as appropriate.

Furthermore, in the above embodiment, the first bus bar 200 is a N-pole bus bar, and the second bus bar 300 is a P-pole bus bar. However, the first bus bar 200 may be a P-pole bus bar, and the second bus bar 300 may be a N-pole bus bar.

Furthermore, in the above embodiment, the film capacitor 1 is provided with four capacitor elements 100. However, the number of capacitor elements 100 can be changed as appropriate, including the case where there is only one capacitor element.

Furthermore, in the above embodiment, the capacitor element 100 is formed by stacking two metallized films with aluminum vapor-deposited on a dielectric film and rolling or laminating the stacked metallized films, but in addition, these capacitor elements 100 may also be formed by stacking a metallized film with aluminum vapor-deposited on both sides of a dielectric film and an insulating film, and rolling or laminating the resulting film.

Furthermore, in the above embodiment, a film capacitor 1 is given as an example of a capacitor of the present invention. However, the present invention can also be applied to capacitors other than the film capacitor 1.

In addition, the embodiments of the present invention may be modified in various ways as appropriate within the scope of the technical ideas set forth in the claims.

In addition, in the description of the above embodiment, terms indicating directions such as "upper" and "lower" indicate relative directions that depend only on the relative positional relationship of the components, and do not indicate absolute directions such as vertical or horizontal.

The present invention is useful for capacitors used in various electronic devices, electrical devices, industrial equipment, vehicle electrical equipment, etc.

1. Film capacitor (capacitor)
100 Capacitor element 110 First electrode (electrode)
120 Second electrode (electrode)
200 First bus bar 210 Electrode terminal portion (electrode connection portion)
220 Terminal forming part (first extending part)
221 Connection terminal 230 Heat dissipation portion (second extension portion)
300 Second bus bar 310 Electrode terminal portion (electrode connection portion)
320 Terminal formation part (first extension part)
321 Connection terminal 330 Heat dissipation portion (second extension portion)
400 Case 401 Bottom portion 500 Filling resin 1A Film capacitor (capacitor)
710 Capacitor element 711 First electrode (electrode)
712 Second electrode (electrode)
720 First bus bar 721 Electrode terminal portion (electrode connection portion)
722 Terminal forming part (first extending part)
723 Heat radiation part (second extension part)
726 Connection terminal 730 Second bus bar 731 Electrode terminal portion (electrode connection portion)
732 Terminal forming part (first extending part)
735 Connection terminal 736 Heat dissipation portion (second extension portion)
740 Case 750 Filling resin

Claims (8)

a capacitor element having a first electrode and a second electrode opposed to each other;
a first bus bar and a second bus bar connected to the first electrode and the second electrode, respectively;
a case having a bottom surface portion and a first side surface portion and a second side surface portion rising from the bottom surface portion and facing each other, the case housing the capacitor element;
A filling resin is filled in the case,
the capacitor element is accommodated in the case such that the second electrode faces a bottom surface of the case,
The first bus bar is
a first electrode connection portion covering at least a portion of the first electrode and connected to the first electrode;
a first bus bar first extension portion that extends from one end of the first electrode connection portion to the outside of the filling resin and has a first connection terminal at a portion exposed from the filling resin to be connected to an external terminal;
a first bus bar second extension portion extending from an end of the first electrode connection portion different from the one end along a circumferential surface of the capacitor element toward a bottom portion of the case,
The second bus bar is
a second electrode connection portion covering at least a portion of the second electrode and connected to the second electrode;
a second bus bar first extension portion that extends from one end of the second electrode connection portion to the outside of the filled resin along a portion of the peripheral surface of the capacitor element that faces away from a portion of the peripheral surface along which the first bus bar second extension portion runs, and has a second connection terminal that is connected to an external terminal at a portion exposed from the filled resin,
a connection terminal that extends outside the filling resin and is connected to an external terminal is not connected to the second extending portion of the first bus bar,
the first bus bar second extension portion is arranged along the second side surface portion of the case.
A capacitor characterized by: 2. The capacitor according to claim 1,
the second bus bar further includes a second bus bar second extension portion extending from an end of the second electrode connection portion different from the one end along a circumferential surface of the capacitor element toward an opening side of the case.
A capacitor characterized by: 3. The capacitor according to claim 2 ,
the second bus bar second extension portion is arranged along the second side surface portion of the case.
A capacitor characterized by: The capacitor according to claim 1 or 2,
Three or more capacitor elements including the capacitor element are arranged in a row in the case,
the first bus bar second extension portion extends from an end of the first electrode connection portion in a direction perpendicular to a direction in which the three or more capacitor elements are arranged;
A capacitor characterized by: 2. The capacitor according to claim 1 ,
a predetermined distance is provided between a position of a tip of the second extension portion of the first bus bar and a position of the second electrode;
A capacitor characterized by: 3. The capacitor according to claim 2 ,
a predetermined distance is provided between a tip of the first bus bar second extension portion and a tip of the second bus bar second extension portion;
A capacitor characterized by: a capacitor element having a first electrode and a second electrode opposed to each other;
a first bus bar and a second bus bar connected to the first electrode and the second electrode, respectively;
a case having a bottom surface portion and a first side surface portion and a second side surface portion rising from the bottom surface portion and facing each other, the case housing the capacitor element;
A filling resin is filled in the case,
the capacitor element is accommodated in the case such that the first electrode and the second electrode face the first side surface portion and the second side surface portion of the case, respectively;
The first bus bar is
a first electrode connection portion covering at least a portion of the first electrode and connected to the first electrode;
a first bus bar first extension portion that extends from one end of the first electrode connection portion to the outside of the filling resin and has a first connection terminal at a portion exposed from the filling resin to be connected to an external terminal;
a first bus bar second extension portion extending from an end of the first electrode connection portion different from the one end along a portion of the circumferential surface of the capacitor element that faces the bottom surface portion,
The second bus bar is
a second electrode connection portion covering at least a portion of the second electrode and connected to the second electrode;
a second bus bar first extension portion that extends from one end of the second electrode connection portion to the outside of the filling resin and has a second connection terminal at a portion exposed from the filling resin to be connected to an external terminal,
Three or more capacitor elements including the capacitor element are arranged in a row in the case,
the first electrode connection portion has a plate shape parallel to surfaces of the first electrodes of the three or more capacitor elements;
the first bus bar second extension portion extends from an end of the first electrode connection portion facing the bottom surface portion in a direction perpendicular to a direction in which the three or more capacitor elements are arranged, along a portion of a peripheral surface of all of the three or more capacitor elements facing the bottom surface portion.
A capacitor characterized by: 8. The capacitor according to claim 7,
the second bus bar further includes a second bus bar second extension portion extending from an end of the second electrode connection portion other than the one end toward the first bus bar second extension portion along a portion of the circumferential surface of the capacitor element that faces the bottom surface portion,
A capacitor characterized by:

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