JP7492923B2 - Film capacitor - Google Patents

Description

The present invention relates to a film capacitor.

Conventionally, power conversion devices that supply three-phase AC power to the motors of electric vehicles such as hybrid cars and electric automobiles are known. The power conversion device includes a DC/DC converter, an inverter, a control circuit, and a film capacitor. The DC/DC converter boosts and outputs DC power supplied from a battery, and the inverter converts the output of the DC/DC converter into three-phase AC power and supplies it to the motor. The control circuit controls the DC/DC converter and the inverter. The film capacitor is provided between the DC/DC converter and the inverter, and functions as a smoothing capacitor.

The film capacitor includes multiple film capacitor elements, an N-pole N bus bar, a P-pole P bus bar, and a case to house them (see, for example, Patent Document 1). The N bus bar and the P bus bar include N-pole and P-pole input terminals that are connected to a DC/DC converter as lead-out terminals.

The above-mentioned film capacitor has a problem in that the input terminal is exposed from the case, and therefore cannot be insulated from other components (e.g., a circuit board including a control circuit). In addition, the above-mentioned film capacitor has a problem in that there is no guide for positioning the input terminal.

JP 2013-251351 A

The present invention was made in consideration of the above circumstances, and its objective is to provide a film capacitor that can ensure insulation between the lead-out terminal and other components and that allows the lead-out terminal to be positioned.

In order to solve the above problems, the film capacitor according to the present invention comprises:
a film capacitor element having a first electrode and a second electrode;
A first bus bar having a first polarity connected to the first electrode;
A second bus bar having a second polarity connected to the second electrode;
a case having a storage space for storing the film capacitor element, the first bus bar, and the second bus bar;
A film capacitor comprising:
the first bus bar includes a first pole main plate housed in the case and a first pole lead terminal exposed from the case,
the second bus bar includes a second pole main plate housed in the case and a second pole lead terminal exposed from the case,
The case is
A bottom portion provided below the storage space;
A peripheral wall portion surrounding the storage space on all four sides;
A case pocket provided on the peripheral wall portion;
Equipped with
At least one of the first pole lead terminals includes a first pole tip portion facing the peripheral wall portion,
The first pole tip portion has a first through hole for fastening formed therein,
At least one of the second pole lead terminals includes a second pole tip portion facing the peripheral wall portion so as to be adjacent to the first pole tip portion,
The second pole tip portion has a second through hole for fastening formed therein,
The case pocket includes:
The present invention is characterized in that it has a first folded portion that covers the lower surface and lower outer surface of the first pole tip portion with the first through hole exposed, and that covers the lower surface and lower outer surface of the second pole tip portion with the second through hole exposed.

With this configuration, the lower surface and the lower part of the outer surface of the tip portion (first pole tip portion and second pole tip portion) of the pull-out terminal are covered with the first folded portion of the case pocket, so insulation between the pull-out terminal and other components can be ensured. In addition, with this configuration, it is possible to position the pull-out terminal in the vertical direction using the first folded portion. Note that in the first pole tip portion and the second pole tip portion, the outer surface is the surface opposite the surface (inner surface) facing the peripheral wall portion.

In the above film capacitor,
The case pocket includes:
The electrode may be configured to include a second folded portion that covers one side surface of the first pole tip portion and the other side surface of the second pole tip portion, which do not face each other.

This configuration makes it possible to further ensure insulation between the pull-out terminal and other components (e.g., insulation in the left-right direction), and also makes it possible to position the pull-out terminal in another direction (e.g., left-right direction) using the second return portion.

In the above film capacitor,
The peripheral wall portion can be configured so that a first nut is provided at a position facing the first through hole of the first pole tip portion, and a second nut is provided at a position facing the second through hole of the second pole tip portion.

In the above film capacitor,
the first bus bar includes a first pole input terminal and a first pole output terminal as the first pole lead terminals,
the second bus bar includes a second pole input terminal and a second pole output terminal as the second pole lead terminals,
The first pole input terminal may be configured to include the first pole tip portion and the second pole input terminal may be configured to include the second pole tip portion.

In the above film capacitor,
the first pole output terminal and the second pole output terminal extend from above at least one of the left and right sides of the peripheral wall portion in parallel with a lower surface of the bottom portion and are drawn out to the outside of the case,
The bottom surface of the bottom portion may be provided with an attachment portion to which an attachment target can be attached.

The present invention provides a film capacitor that can ensure insulation between the lead-out terminal and other components and allows the lead-out terminal to be positioned.

1 is a block diagram of a power conversion device equipped with a film capacitor according to the present invention. 1 is a perspective view of a film capacitor according to the present invention; 1 is an exploded perspective view of a film capacitor according to the present invention; 1A is a diagram showing an output terminal of an N bus bar, and FIG. 1B is a diagram showing an output terminal of a P bus bar. 1A is a perspective view of a case of a film capacitor according to the present invention, and FIG. 1B is a perspective view of the case from below. FIG. 2 is an enlarged view of a case pocket of the film capacitor according to the present invention. 1A and 1B are diagrams showing the relationship between a case pocket and an input terminal in a film capacitor according to the present invention, in which (A) is a cross-sectional view and (B) is a schematic view thereof.

The film capacitor according to the present invention will be described below with reference to the attached drawings. Note that the front-back direction X, left-right direction Y, and up-down direction Z indicated by arrows in the drawings are linear directions that are perpendicular to each other.

Figure 1 shows a power conversion device 1 equipped with a film capacitor C according to one embodiment of the present invention. In addition to the film capacitor C, the power conversion device 1 includes a DC/DC converter A, inverters B1 and B2, a control circuit D, and a housing E that houses these components. The power conversion device 1 is installed in an electric vehicle such as a hybrid vehicle or an electric car, for example, and converts DC power supplied from a battery 2 into AC power and supplies it to motors 3 and 4.

Under the control of the control circuit D, the DC/DC converter A boosts the DC power input from the battery 2 and outputs the boosted DC power to the film capacitor C. The DC/DC converter A is composed of, for example, an insulating transformer, a switching circuit on the primary side, and a rectifying and smoothing circuit on the secondary side.

Under the control of the control circuit D, the inverter B1 converts the three-phase DC power input from the film capacitor C into three-phase AC power and outputs the three-phase AC power to the motor 3. Similarly, under the control of the control circuit D, the inverter B2 converts the three-phase DC power input from the film capacitor C into three-phase AC power and outputs the three-phase AC power to the motor 4. The inverters B1 and B2 each include a U-phase switch circuit that generates U-phase AC power, a V-phase switch circuit that generates V-phase AC power, and a W-phase switch circuit that generates W-phase AC power. Each switch circuit can be composed of, for example, switching elements connected in series.

In this embodiment, the inverters B1 and B2 have input terminals corresponding to the output terminals of the film capacitors C. Specifically, the switch circuits of each phase of the inverters B1 and B2 have an N input terminal, a first P input terminal, and a second P input terminal. For example, the first P input terminal and the second P input terminal are connected to one end of the switch circuit, and the N input terminal is connected to the other end of the switch circuit.

As described above, the control circuit D controls the DC/DC converter A and the inverters B1 and B2. The control circuit D can be configured as an analog control circuit, a digital control circuit including a microcontroller, or a combination of both. In this embodiment, the circuit board including the control circuit D is attached to the underside of the film capacitor C as the mounting target.

The housing E is made of metal (e.g., aluminum) and houses the DC/DC converter A, the inverters B1 and B2, the film capacitor C, and the control circuit D.

Film capacitor C is provided between DC/DC converter A and inverters B1 and B2, and functions as a smoothing capacitor. Figure 2 shows a perspective view of film capacitor C, and Figure 3 shows an exploded perspective view of film capacitor C.

The film capacitor C includes a capacitor element portion 10, an N bus bar 20 corresponding to the "first bus bar of first polarity" of the present invention, a P bus bar 30 corresponding to the "second bus bar of second polarity" of the present invention, a case 40, an insulating portion 50, and a sealing resin 60. Note that the sealing resin 60 is omitted in FIG. 3.

The capacitor element section 10 has eight film capacitor elements 11 (corresponding to the "film capacitor elements" of the present invention) that function as smoothing capacitors.

Film capacitor element 11 is formed by overlapping and winding a pair of metallized films, each having a metal film formed on the surface of a dielectric film as internal electrodes (cathode, anode), with metallikon sections formed as external electrodes at both winding ends. One metallikon section (corresponding to the "first electrode" of the present invention) is connected to the internal electrode (cathode) of one metallized film, and the other metallikon section (corresponding to the "second electrode" of the present invention) is connected to the internal electrode (anode) of the other metallized film. Film capacitor element 11 is placed in case 40 with the first electrode on the lower side and the second electrode on the upper side.

The N busbar 20 is an electrode terminal component formed by processing a metal plate, and is a busbar for the cathode. The N busbar 20 comprises an N main plate 21 which corresponds to the "first pole main plate" of the present invention, an N input terminal 22 which corresponds to the "first pole input terminal" of the present invention, and an N output terminal 23 which corresponds to the "first pole output terminal" of the present invention. The N input terminal 22 and the N output terminal 23 function as the "first pole lead terminal" of the present invention.

The N main plate 21 is housed in the case 40 and is connected to the lower first electrode of the film capacitor element 11.

The N input terminal 22 is pulled out from the front end of the N main plate 21 and exposed on the front surface of the case 40, and is connected to the output terminal for the negative pole of the DC/DC converter A. The N input terminal 22 has an N tip portion 22A (corresponding to the "first pole tip portion" of the present invention) facing the front surface of the case 40. The N tip portion 22A has a first through hole H1 (a round hole in this embodiment) formed as an input portion for fastening to the DC/DC converter A.

The N output terminals 23 are pulled out from the left and right ends of the N main board 21 to the outside of the case 40. As shown in FIG. 4(A), the N output terminals 23 include an N output terminal 23U for the U phase, an N output terminal 23V for the V phase, and an N output terminal 23W for the W phase. Note that while FIG. 4(A) only shows the N output terminal 23 on the left side, the N output terminal 23 on the right side has the same configuration as the left side.

The N output terminals 23U, 23V, and 23W have through holes formed as output sections for fastening to the N input terminals of the switch circuits of each phase of the inverter B1. The N output terminals 23U, 23V, and 23W are connected to the N input terminals of the switch circuits of the U, V, and W phases of the inverter B1, respectively.

The P bus bar 30 is an electrode terminal part formed by processing a metal plate, and is a bus bar for the anode. The P bus bar 30 includes a P main plate 31, which corresponds to the "second pole main plate" of the present invention, a P input terminal 32, which corresponds to the "second pole input terminal" of the present invention, and a P output terminal 33, which corresponds to the "second pole output terminal" of the present invention. The P input terminal 32 and the P output terminal 33 function as the "second pole lead terminal" of the present invention.

The P main board 31 is housed in the case 40 and is connected to the upper second electrode of the film capacitor element 11.

The P input terminal 32 is pulled out from the front end of the P main board 31 and exposed on the front surface of the case 40 so as to be adjacent to the N input terminal 22, and is connected to the anode output terminal of the DC/DC converter A. The P input terminal 32 has a P tip portion 32A (corresponding to the "second pole tip portion" of the present invention) facing the front surface of the case 40. A second through hole H2 (a round hole in this embodiment) for fastening to the DC/DC converter A is formed in the P tip portion 32A as an input portion.

The P output terminals 33 are pulled out from the left and right ends of the P main board 31 to the outside of the case 40. As shown in FIG. 4(B), the P output terminals 33 include P output terminals 33U, 33U' for the U phase, P output terminals 33V, 33V' for the V phase, and P output terminals 33W, 33W' for the W phase. However, the P output terminals 33U' and 33V are a single common first common terminal 33UV, and the P output terminals 33V' and 33W are a single common second common terminal 33VW. Note that while FIG. 4(B) shows only the P output terminal 33 on the left side, the P output terminal 33 on the right side has the same configuration as the left side.

The P output terminal 33U, the first common terminal 33UV, the second common terminal 33VW, and the P output terminal 33W' are formed with through holes for fastening to the P input terminals of the switch circuits of each phase of the inverter B1 as output sections. The P output terminal 33U is connected to the first P input terminal of the U-phase switch circuit. The first common terminal 33UV is connected to the second P input terminal of the U-phase switch circuit on the P output terminal 33U side, and is connected to the first P input terminal of the V-phase switch circuit on the second common terminal 33VW side. The second common terminal 33VW is connected to the second P input terminal of the V-phase switch circuit on the first common terminal 33UV side, and is connected to the first P input terminal of the W-phase switch circuit on the P output terminal 33W' side. The P output terminal 33W' is connected to the second P input terminal of the W-phase switch circuit.

The case 40 is a housing formed from an insulating resin. As shown in FIG. 5, the case 40 includes a bottom portion 41, a peripheral wall portion 42, a case pocket 43, and an attachment portion 44.

The bottom 41 is provided so as to be located below the N main board 21 of the N bus bar 20. As shown in FIG. 5(B), the underside of the bottom 41 is provided with a plurality of mounting portions 44 to which a circuit board can be attached. In this embodiment, a control circuit D is attached to the mounting portions 44.

The peripheral wall portion 42 is composed of a front wall 42F, a rear wall 42B, a left wall 42L, and a right wall 42R, and is provided to surround the four sides (front, rear, left, and right) of the N main plate 21. The peripheral wall portion 42 and the bottom portion 41 form a storage space for storing the N main plate 21 of the N bus bar 20, the capacitor element portion 10, and the P main plate 31 of the P bus bar 30.

A first nut 45 is provided on the front wall 42F at a position facing the first through hole H1 of the N tip portion 22A, and a second nut 46 is provided on the front wall 42F at a position facing the second through hole H2 of the P tip portion 32A. In this embodiment, the first nut 45 and the second nut 46 are fitted into recesses formed in the front wall 42F. For example, the first nut 45 and the second nut 46 are provided on the front wall 42F by insert molding.

The case pocket 43 is provided on the front surface of the front wall 42F. As shown in Figures 6 and 7, the case pocket 43 has a first folded portion 43D that constitutes the lower pocket, and second folded portions 43L and 43R that constitute the left and right pockets.

The first folded portion 43D covers the lower surface and lower outer surface (in this embodiment, the lower front surface) of the N tip portion 22A while exposing the first through hole H1 of the N tip portion 22A, and covers the lower surface and lower outer surface (in this embodiment, the lower front surface) of the P tip portion 32A while exposing the second through hole H2 of the P tip portion 32A.

As shown in FIG. 7B, the first return portion 43D can ensure a creepage distance (L1+L2+L3) for insulating the N tip portion 22A from other components (e.g., control circuit D). Similarly, the first return portion 43D can ensure a creepage distance for insulating the P tip portion 32A from other components.

The first folded portion 43D also allows the N tip portion 22A and the P tip portion 32A to be positioned in the up-down direction. For example, the N main plate 21 and the P main plate 31 can be stored in the case 40 so that the underside of the N tip portion 22A contacts the opposing surface of the first folded portion 43D that faces the underside, and the underside of the P tip portion 32A contacts the aforementioned opposing surface.

The second return portion 43L covers the left side surface and the left front surface of the N tip portion 22A while exposing the first through hole H1 of the N tip portion 22A. The lower end of the second return portion 43L is connected to the left end of the first return portion 43D, and the upper end of the second return portion 43L is located higher than the upper end of the first nut 45. The second return portion 43R covers the right side surface and the right front surface of the P tip portion 32A while exposing the second through hole H2 of the P tip portion 32A. The lower end of the second return portion 43R is connected to the right end of the first return portion 43D, and the upper end of the second return portion 43R is located higher than the upper end of the second nut 46.

The second return portions 43L, 43R can ensure a creepage distance to insulate the P tip portion 32A and the N tip portion 22A from other components (e.g., the housing E). The second return portions 43L, 43R also enable the left-right positioning of the N tip portion 22A and the P tip portion 32A. For example, the N main board 21 and the P main board 31 can be stored in the case 40 so that the left side surface of the N tip portion 22A contacts the opposing surface of the second return portion 43L that faces the left side surface, and the right side surface of the P tip portion 32A contacts the opposing surface of the second return portion 43R that faces the right side surface.

The mounting portion 44 is provided on the underside of the bottom 41. On the other hand, the N output terminal 23 and the P output terminal 33 each extend parallel to the underside of the bottom 41 from above the left wall 42L and above the right wall 42R and are pulled out to the outside of the case 40. In other words, the N output terminal 23 and the P output terminal 33 are located above the storage space of the case 40, and the mounting portion 44 is located below the storage space. With this structure, in this embodiment, it is possible to ensure insulation between the N output terminal 23 and the P output terminal 33 and the control circuit D.

Referring again to FIG. 3, the insulating section 50 is provided to prevent a short circuit between the N bus bar 20 and the P bus bar 30. The insulating section 50 includes a first insulating member 51, a second insulating member 52, and a third insulating member 53. The first insulating member 51 is disposed between the front end of the N main board 21 and the front end of the P main board 31. The second insulating member 52 is disposed between the left end of the N main board 21 and the left end of the P main board 31. The third insulating member 53 is disposed between the right end of the N main board 21 and the right end of the P main board 31.

The sealing resin 60 is a resin for protecting the capacitor element portion 10 housed in the storage space inside the case 40. The sealing resin 60 is, for example, a potting resin such as epoxy resin that is filled into the case 40 in a predetermined amount using a dispenser and then hardened.

As described above, the film capacitor C according to this embodiment is characterized by having a case pocket 43 formed by a first return portion 43D and second return portions 43L, 43R. According to the film capacitor C according to this embodiment, it is possible to ensure insulation between the N input terminal 22 and the P input terminal 32 and other components without increasing the size of the case 40, and it is possible to position the N input terminal 22 and the P input terminal 32 using the case pocket 43.

[Modification]
Although the embodiment of the film capacitor according to the present invention has been described above, the present invention is not limited to the above embodiment.

The film capacitor according to the present invention comprises a film capacitor element, a first bus bar, a second bus bar, and a case, the case comprising a bottom, a peripheral wall, and a case pocket provided in the peripheral wall, at least one of the first pole lead terminals of the first bus bar comprises a first pole tip portion facing the peripheral wall portion, at least one of the second pole lead terminals of the second bus bar comprises a second pole tip portion facing the peripheral wall portion so as to be adjacent to the first pole tip portion, and the configuration can be modified as appropriate as long as the case pocket covers the lower surface and the lower outer surface of the first pole tip portion with the first through hole formed in the first pole tip portion exposed, and covers the lower surface and the lower outer surface of the second pole tip portion with the second through hole formed in the second pole tip portion exposed.

For example, in the above embodiment, the first pole input terminal and the second pole input terminal each have a first pole tip portion and a second pole tip portion, but instead of or in addition to this, the first pole output terminal and the second pole output terminal may each have a first pole tip portion and a second pole tip portion. That is, the film capacitor according to the present invention may be configured to have a first case pocket that covers the first pole tip portion and the second pole tip portion of each input terminal, and/or a second case pocket that covers the first pole tip portion and the second pole tip portion of each output terminal.

In the above embodiment, the case pocket 43 is composed of the first folded portion 43D and the second folded portions 43L and 43R, but the case pocket of the present invention only needs to be composed of at least the first folded portion 43D.

The first flaps 43D may be composed of a flaps that cover the underside and lower front surface of the N tip 22A while exposing the first through hole H1 of the N tip 22A, and a flaps that cover the underside and lower front surface of the P tip 32A while exposing the second through hole H2 of the P tip 32A, which are separate from each other.

The film capacitor according to the present invention may be a so-called resinless film capacitor that does not have sealing resin 60.

In the above embodiment, the film capacitor is compatible with three phases, U, V, and W, but the film capacitor of the present invention may be compatible with one or two phases, or with four or more phases.

In the above embodiment, the P output terminals 33 are arranged on both sides of the N output terminal 23 in each phase, but the N output terminals 23 may be arranged on both sides of the P output terminal 33 in each phase. In that case, instead of the P bus bar 30, the N bus bar 20 is configured to have a first common terminal and a second common terminal.

A DC/DC converters B1, B2 Inverter C Film capacitor D Control circuit E Housing 1 Power conversion device 2 Batteries 3, 4 Motor 10 Capacitor element section 11 Film capacitor element 20 N bus bar 21 N main plate 22 N input terminal 22A N tip portion 23 N output terminal 30 P bus bar 31 P main plate 32 P input terminal 32A P tip portion 33 P output terminal 33UV First common terminal 33VW Second common terminal 40 Case 41 Bottom portion 42 Peripheral wall portion 43 Case pocket 43D First folded portion 43L, 43R Second folded portion 44 Mounting portion 45 First nut 46 Second nut 50 Insulating portion 51 First insulating member 52 Second insulating member 53 Third insulating member 60 Sealing resin

Claims (5)

a film capacitor element having a first electrode and a second electrode;
A first bus bar having a first polarity connected to the first electrode;
A second bus bar having a second polarity connected to the second electrode;
a case having a storage space for storing the film capacitor element, the first bus bar, and the second bus bar;
A film capacitor comprising:
the first bus bar includes a first pole main plate housed in the case and a first pole lead terminal exposed from the case,
the second bus bar includes a second pole main plate housed in the case and a second pole lead terminal exposed from the case,
The case is
A bottom portion provided below the storage space;
A peripheral wall portion surrounding the storage space on all four sides;
A case pocket provided on the peripheral wall portion;
Equipped with
At least one of the first pole lead terminals includes a first pole tip portion facing the peripheral wall portion,
The first pole tip portion has a first through hole for fastening formed therein,
At least one of the second pole lead terminals includes a second pole tip portion facing the peripheral wall portion so as to be adjacent to the first pole tip portion,
The second pole tip portion has a second through hole for fastening formed therein,
The case pocket includes:
a first folded portion covering a lower surface and a lower portion of an outer surface of the first pole tip portion with the first through hole exposed, and covering a lower surface and a lower portion of an outer surface of the second pole tip portion with the second through hole exposed ;
The first folded portion is in contact with the lower surface of the first pole tip portion and the lower surface of the second pole tip portion.
A film capacitor characterized by: The case pocket includes:
2. The film capacitor according to claim 1, further comprising a second folded portion covering one side surface of the first pole tip portion and the other side surface of the second pole tip portion which are not opposed to each other. The film capacitor described in claim 1 or 2, characterized in that a first nut is provided on the peripheral wall portion at a position facing the first through hole of the first pole tip portion, and a second nut is provided at a position facing the second through hole of the second pole tip portion. the first bus bar includes a first pole input terminal and a first pole output terminal as the first pole lead terminals,
the second bus bar includes a second pole input terminal and a second pole output terminal as the second pole lead terminals,
The film capacitor according to any one of claims 1 to 3, characterized in that the first pole input terminal has the first pole tip portion and the second pole input terminal has the second pole tip portion. the first pole output terminal and the second pole output terminal extend from above at least one of the left and right sides of the peripheral wall portion in parallel with a lower surface of the bottom portion and are drawn out to the outside of the case,
5. The film capacitor according to claim 4, wherein a mounting portion to which an object can be attached is provided on the lower surface of the bottom portion.

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