JP2022110539A - Film capacitor, inverter, and motor vehicle - Google Patents

Abstract

To provide a film capacitor that can prevent an increase in ESR, an inverter, and a motor vehicle.SOLUTION: A film capacitor 100 comprises a plurality of capacitor elements 1, a bus bar 2, and an insulating member 3. The plurality of capacitor elements 1 constitute a first element array 11 and a second element array 12 in which elements are arranged. In a state in which a first bus bar 21 and a second bus bar 22 are connected with the capacitor elements 1 in the first element array 11 and the capacitor elements 1 in the second element array 12, the insulating member 3 is sandwiched by a first bus bar main body 21a and a second bus bar main body 22a. In the first bus bar 21, the length of a first branch connection part 21b connected with the first element array 11 and the length of a second branch connection part connected with the second element array 12 are same as each other, and in the second bus bar 22, the length of a third branch connection part 22b connected with the first element array 11 and the length of a fourth branch connection part 22c connected with the second element array 12 are same as each other.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to film capacitors, inverters and electric vehicles.

A film capacitor element is formed, for example, by winding a metallized film in which a metal film serving as an electrode is vapor-deposited on the surface of a dielectric film made of polypropylene resin, or by stacking a plurality of films in one direction.

In the film capacitor described in Patent Document 1, a plurality of film capacitor elements are connected by bus bars, housed in a case, and filled with resin.

WO2017/081853

When connecting a plurality of capacitor elements with a bus bar like the film capacitor described in Patent Document 1, the capacitor elements are arranged in a plurality of rows. Since the connection positions and the like of the busbars and the capacitor elements in each row are different for each element row, unnecessary inductance may occur depending on the element row. Unwanted inductance causes disturbances in the frequency characteristics of impedance. This disturbance increases the ESR (equivalent series resistance) of the film capacitor, which may cause damage due to heat generation.

An object of the present disclosure is to provide a film capacitor, an inverter, and an electric vehicle capable of suppressing an increase in ESR.

A film capacitor of the present disclosure includes a first element row in which a plurality of capacitor elements are arranged,
a second element row in which a plurality of capacitor elements are arranged;
a first bus bar main body, a first branch connection portion branched from the first bus bar main body and electrically connected to each capacitor element of the first element array, and each of the second element array branched from the first bus bar main body a first bus bar including a second branch connection electrically connected to the capacitor element;
a second bus bar main body, a third branch connection portion branched from the second bus bar main body and electrically connected to each capacitor element of the first element row, and each of the second element rows branched from the second bus bar main body a second bus bar including a fourth branch connection electrically connected to the capacitor element;
an insulating member that electrically insulates the first busbar and the second busbar,
In a state in which the first bus bar and the second bus bar are connected to each capacitor element of the first element row and each capacitor element of the second element row, the insulating member is provided with the first bus bar body and the second bus bar. It is sandwiched between the main body of the busbar and
The length of the first branch connection and the length of the second branch connection are the same,
The length of the third branch connection portion and the length of the fourth branch connection portion are the same.

An inverter of the present disclosure includes a bridge circuit configured by switching elements, and a capacitive section connected to the bridge circuit and including the film capacitor described above.

An electric vehicle according to the present disclosure includes a power source, the above inverter connected to the power source, a motor connected to the inverter, and wheels driven by the motor.

According to the present disclosure, the insulating member is sandwiched between the first busbar main body and the second busbar main body, and the length of the first branch connection portion branching from the first busbar main body and the length of the second branch connection portion are different. The length of the third branch connection portion branching from the second bus bar main body and the length of the fourth branch connection portion are the same. As a result, disturbance in frequency characteristics of impedance can be suppressed, and an increase in ESR (equivalent series resistance) of the film capacitor can be suppressed.

According to the present disclosure, it is possible to provide an inverter and an electric vehicle using a film capacitor that suppresses an increase in ESR.

It is a perspective view which shows the external appearance of a film capacitor. 1 is an exploded perspective view showing the structure of a film capacitor; FIG. 1 is a plan view of a film capacitor; FIG. It is a side view of a film capacitor. FIG. 4 is a perspective view showing the appearance of a film capacitor of another embodiment; 2 is a schematic configuration diagram for explaining the configuration of an inverter; FIG. 1 is a schematic configuration diagram for explaining the configuration of an electric vehicle; FIG.

The film capacitor of the present disclosure will be described below with reference to the drawings. FIG. 1 is a perspective view showing the appearance of a film capacitor. FIG. 2 is an exploded perspective view showing the configuration of the film capacitor. 3A is a plan view of the film capacitor, and FIG. 3B is a side view of the film capacitor. A film capacitor 100 of this embodiment includes a plurality of capacitor elements 1 , bus bars 2 , and insulating members 3 .

The plurality of capacitor elements 1 constitute a first element row 11 in which a plurality of capacitor elements 1 are arranged and a second element row 12 in which a plurality of capacitor elements 1 are arranged. Hereinafter, the capacitor element 1 included in the first element row 11 may be referred to as a capacitor element 1a, and the capacitor element 1 included in the second element row 12 may be referred to as a capacitor element 1b. Capacitor element 1 may be, for example, a laminate type or wound type capacitor element in which metallized films are laminated. Each capacitor element 1a included in the first element row 11 may be the same type of capacitor element. Each capacitor element 1b included in the second element row 12 may be the same type of capacitor element. Each capacitor element 1 has two connections 5, 6, positive and negative. Capacitor element 1 includes positive and negative metallikon electrodes (not shown), and connection portions 5 and 6 are members for connecting the metallikon electrodes and bus bar 2 . The connecting portions 5 and 6 are made of a conductive material such as solder, for example.

In the example shown in FIG. 1 and the like, each of the first element row 11 and the second element row 12 is configured by arranging four capacitor elements 1, but the first element row 11 and the second element row 12 is not particularly limited. Moreover, the film capacitor 100 may have at least the first element row 11 and the second element row 12, and may have three or more element rows such as a third element row and a fourth element row. The first element row 11 and the second element row 12 are arranged so that their arrangement directions are parallel to each other. Each capacitor element 1 has, for example, a rectangular parallelepiped shape, and by arranging the rectangular parallelepiped capacitor elements 1, the first element row 11 and the second element row 12 also have a rectangular parallelepiped shape. In the rectangular parallelepiped first element row 11, the positive electrode connection portion 5 of each capacitor element 1a is located on the same surface, and the negative electrode connection portion 6 is located on the same surface on the opposite side of the positive electrode. In the rectangular parallelepiped second element row 12, the positive electrode connection portion 5 of each capacitor element 1b is located on the same surface, and the negative electrode connection portion 6 is located on the same surface on the side opposite to the positive electrode. The connection portion 5 of the first element row 11 and the connection portion 5 of the second element row 12 are on the same side, and the connection portion 6 of the first element row 11 and the connection portion 6 of the second element row 12 are connected It is on the opposite side of part 5.

Busbar 2 includes a first busbar 21 and a second busbar 22 . First bus bar 21 is electrically connected to connecting portion 5 of each capacitor element 1 a included in first element row 11 and to connecting portion 5 of each capacitor element 1 b included in second element row 12 . Second bus bar 22 is electrically connected to connecting portion 6 of each capacitor element 1 a included in first element row 11 and connecting portion 6 of each capacitor element 1 b included in second element row 12 . That is, the first busbar 21 is a positive electrode busbar, and the second busbar 22 is a negative electrode busbar. The busbar 2 is made of a conductive material such as copper, for example.

The first busbar 21 includes a first busbar main body 21a, first branch connection portions 21b branched from the first busbar main body 21a and electrically connected to the respective capacitor elements 1a of the first element row 11, and the first busbar main body 21a. and a second branch connection portion 21 c branched from and electrically connected to each capacitor element 1 b of the second element row 12 . The second busbar 22 includes a second busbar main body 22a, a third branch connection portion 22b branched from the second busbar main body 22a and electrically connected to each capacitor element 1a of the first element row 11, and a second busbar main body 22a. and a fourth branch connection portion 22 c branched from and electrically connected to each capacitor element 1 b of the second element row 12 .

With the first bus bar 21 and the second bus bar 22 connected to the capacitor elements 1 a of the first element row 11 and the capacitor elements 1 b of the second element row 12 , the insulating member 3 connects the first bus bar body 21 a and the second 2 and the busbar main body 22a. The insulating member 3 may be a member that electrically insulates the first busbar 21 and the second busbar 22, and for example, a plate-like, sheet-like, or film-like member made of an insulating material such as polyester resin is used. be able to.

In this embodiment, the first busbar main body 21a and the second busbar main body 22a are strip-shaped. The insulating member 3 sandwiched between them is also, for example, strip-shaped. For example, the strip-shaped first busbar main body 21a and the strip-shaped second busbar main body 22a may have the same length in the width direction. In a state in which the first bus bar 21 and the second bus bar 22 are assembled so as to be connected to each capacitor element 1, the first bus bar main body 21a and the second bus bar main body 22a overlap each other with the insulating member 3 interposed therebetween. there is The widthwise length of the insulating member 3 is, for example, the same as the widthwise length of the first busbar main body 21a and the second busbar main body 22a, or longer than the widthwise length of the first busbar main body 21a and the second busbar main body 22a. big.

In the first bus bar 21 and the second bus bar 22, the length of the first branch connection portion 21b and the length of the second branch connection portion 21c are the same, and the length of the third branch connection portion 22b and the length of the fourth branch connection portion 22c are the same. Same as length. The length of the first branch connection portion 21b is the distance from the first bus bar main body 21a to the connection portion 5 of each capacitor element 1a of the first element row 11, and the length of the second branch connection portion 21c is the length of the first branch connection portion 21c. It is the distance from the bus bar main body 21 a to the connecting portion 5 of each capacitor element 1 b of the second element row 12 . The length of the third branch connection portion 22b is the distance from the second bus bar body 22a to the connection portion 6 of each capacitor element 1a of the first element row 11, and the length of the fourth branch connection portion 22c is the distance from the second bus bar main body 22a. It is the distance from the bus bar main body 22 a to the connecting portion 6 of each capacitor element 1 b of the second element row 12 .

As described above, the first busbar main body 21a and the second busbar main body 22a are entirely overlapped with the insulating member 3 interposed therebetween, and the inductance components cancel each other out due to electromagnetic coupling. Thereby, the inductance of the first busbar main body 21a and the second busbar main body 22a can be ignored. Then, the inductance generated in the first bus bar 21 is due to the first branch connection portion 21b and the second branch connection portion 21c. Similarly, the inductance generated in the second bus bar 22 is due to the third branch connection portion 22b and the fourth branch connection portion 22c. Here, since the length of the first branch connection portion 21b and the length of the second branch connection portion 21c are the same, their inductances are the same. Similarly, since the length of the third branch connection portion 22b and the length of the fourth branch connection portion 22c are the same, their inductances are the same. As a result, the film capacitor 100 can suppress generation of unnecessary inductance in the first element row 11 and the second element row 12, and can suppress disturbance in the impedance frequency characteristics. As a result, an increase in ESR (equivalent series resistance) of the film capacitor 100 can be suppressed. Suppression of an increase in ESR in the film capacitor 100 can reduce breakage of the film capacitor 100 due to heat generation, for example, and can reduce malfunction of a device in which the film capacitor 100 is mounted.

In the present embodiment, for example, the first branch connection portion 21b and the third branch connection portion 22b are positioned on the first end side of the first busbar main body 21a and the second busbar main body 22a, respectively, and the second branch connection portion 21c and the fourth branch connection portion 22c are located on the second end side of the first busbar main body 21a and the second busbar main body 22a, which are longitudinally opposite to the first end portion. Since the inductance between the first busbar body 21a and the second busbar body 22a can be ignored, the length of the first branch connection portion 21b and the length of the second branch connection portion 21c are the same, and the length of the third branch connection If the length of the portion 22b and the length of the fourth branch connection portion 22c are the same, the ESR (equivalent series resistance) can be suppressed.

In this embodiment, for example, the first busbar main body 21a and the second busbar main body 22a are U-shaped, with the first busbar main body 21a on the outside and the second busbar main body 22a on the inside. It is arranged so that it overlaps with 3 in between. Since the inductance of the first busbar main body 21a and the second busbar main body 22a can be neglected, the first busbar main body 21a and the second busbar main body 22a may have a shape including a bent portion such as a U-shape. Also, an unnecessary increase in inductance due to the shape can be reduced.

In the present embodiment, for example, the second end portions of the first busbar body 21a and the second busbar body 22a are located between the first element row 11 and the second element row 12 . The second branch connection portion 21 c and the fourth branch connection portion 22 c are connected to each capacitor element 1 b of the second element row 12 from the second end portion between the first element row 11 and the second element row 12 . The first end portions of the first busbar main body 21a and the second busbar main body 22a are positioned opposite to the second end portions with the first element row 11 interposed therebetween. The first branch connection portion 21b and the third branch connection portion 22b are connected to each capacitor element 1a of the first element row 11 from the first end.

In this embodiment, for example, the first bus bar 21 and the second bus bar 22 have a first external terminal 21d and a second external terminal 22d for connecting with an external circuit. The first external terminal 21d is located at the first end of the first busbar main body 21a. At the first end of the first busbar main body 21a, the first branch connection portion 21b and the first external terminal 21d are located across the width of the first busbar main body 21a. The second external terminal 22d is located at the first end of the second busbar main body 22a. At the first end of the second busbar main body 22a, the third branch connection portion 22b and the second external terminal 22d are positioned across the width of the second busbar main body 22a.

In the present embodiment, for example, the first branch connection portion 21b is in the shape of a single rectangular plate, and the first of two parallel side portions is connected to the first busbar main body 21a. A second side portion of the portion is connected to each capacitor element 1 a of the first element row 11 . Similarly to the first branch connection portion 21b, the third branch connection portion 22b also has a rectangular plate shape, and the first side portion of the two side portions parallel to each other is connected to the second bus bar main body 22a. The second side of the two sides is connected to each capacitor element 1 a of the first element row 11 . The first branch connection portion 21b is a common connection wiring having one side connected to a plurality of connection portions 5, and the third branch connection portion 22b is a common connection wiring having one side connected to a plurality of connection portions 6. Wiring.

In the present embodiment, for example, the second branch connection portion 21c is in the shape of a plurality of rectangular plates, and each of the first side portions of the two side portions parallel to each other is connected to the first busbar main body 21a. Each of the second side portions of the two side portions is connected to each capacitor element 1 b of the second element row 12 . Similarly to the second branch connection portion 21c, the fourth branch connection portion 22c also has a plurality of rectangular plate shapes, and the first side portions of the two parallel side portions are each connected to the second busbar main body 22a. , the second side of the two sides is connected to each capacitor element 1 b of the second element row 12 . The second branch connection portion 21c is an individual connection wiring in which a plurality of rectangular plate-shaped portions are individually connected to the plurality of connection portions 5, respectively. It is an individual connection wiring that is individually connected to the connection portion 6 .

In the above example, the first branch connection portion 21b and the third branch connection portion 22b are common connection wirings, and the second branch connection portion 21c and the fourth branch connection portion 22c are individual connection wirings. It is not limited to this as long as the configuration can obtain For example, the first branch connection portion 21b and the third branch connection portion 22b may be individual connection wirings, and the second branch connection portion 21c and the fourth branch connection portion 22c may be common connection wirings. Further, the first branch connection portion 21b, the third branch connection portion 22b, the second branch connection portion 21c and the fourth branch connection portion 22c may all be common connection wiring, and the first branch connection portion 21b and the third branch connection portion The connection portion 22b, the second branch connection portion 21c, and the fourth branch connection portion 22c may all be individual connection wirings.

For example, when the film capacitor 100 further includes a third element row, the first busbar main body 21a and the second busbar main body 22a are S-shaped, and the first busbar 21 and the second busbar 22 form the third element row. It is only necessary to have branch connections that connect to the columns. The first busbar main body 21a and the second busbar main body 22a are longer in length and have more bent portions than in the above embodiment. Since the inductance between the first busbar main body 21a and the second busbar main body 22a can be ignored, the branch connection portion connecting to the third element row is the branch connection portion connecting to the first element row and the second element row. , the effect of suppressing the increase in ESR (equivalent series resistance) of the film capacitor 100 can be obtained regardless of the length and shape of the first bus bar main body 21a and the second bus bar main body 22a. The same applies to the case where the film capacitor 100 has a configuration including a fourth element row, a fifth element row, and a large number of element rows.

FIG. 4 is a perspective view showing the appearance of a film capacitor of another embodiment. In addition to the film capacitor 100 described above, the film capacitor 101 further includes a case 8 that accommodates the film capacitor 100 and a filling resin 7 that fills the case 8 . Film capacitor 100 is embedded in filling resin 7 so that first external terminal 21d and second external terminal 22d are exposed. The purpose of the case 8 is to protect the film capacitor 100 housed therein. The filling resin 7 serves to fix the film capacitor 100 in the case and to protect it. The film capacitor 101 can reduce impact from the outside and penetration of moisture by the case 8 and the filling resin 7 . For example, PPS resin (polyphenylene sulfide resin) or the like can be used for the case 8, and epoxy resin or the like can be used for the filling resin 7, for example.

FIG. 5 is a schematic configuration diagram for explaining the configuration of the inverter. FIG. 5 shows an example of an inverter A that generates alternating current from rectified direct current. The inverter A of this embodiment includes a bridge circuit 32 and a capacitor section 33, as shown in FIG. The bridge circuit 32 is composed of, for example, switching elements such as IGBTs (Insulated Gate Bipolar Transistors) and diodes. The capacitive section 33 is arranged between the input terminals of the bridge circuit 32 and stabilizes the voltage. The inverter A may include the above film capacitors 100 and 101 as the capacitive section 33 .

The input of the inverter A may be connected to a booster circuit 35 for boosting the voltage of the DC power supply or may be connected to the DC power supply. On the other hand, the bridge circuit 32 is connected to a motor generator (motor M) as a drive source.

FIG. 6 is a schematic configuration diagram for explaining the configuration of the electric vehicle. FIG. 6 shows an example of a hybrid electric vehicle (HEV) as the electric vehicle B. As shown in FIG. An electric vehicle B in FIG. 6 includes a drive motor 41, an engine 43, a transmission 45, an inverter 47, a power supply (battery) 49, front wheels 51a and rear wheels 51b.

This electric vehicle B has a motor 41, an engine 43, or both as a drive source. The output of the drive source is transmitted via the transmission 45 to the pair of left and right front wheels 51a. The power supply 49 is connected to the inverter 47 and the inverter 47 is connected to the motor 41 .

The electric vehicle B shown in FIG. 6 also includes a vehicle ECU 53 and an engine ECU 57 . The vehicle ECU 53 performs overall control of the electric vehicle B as a whole. The engine ECU 57 drives the electric vehicle B by controlling the rotation speed of the engine 43 . The electric vehicle B further includes driving devices such as an ignition key 55 operated by the driver, an accelerator pedal (not shown), and a brake. A drive signal corresponding to the operation of the driving device by the driver or the like is input to the vehicle ECU. The vehicle ECU 53 outputs instruction signals to the engine ECU 57, the power supply 49, and the inverter 47 as a load based on the drive signal. The engine ECU 57 drives the electric vehicle B by controlling the rotation speed of the engine 43 in response to the instruction signal. The inverter A to which the film capacitors 100 and 101 of the present embodiment are applied as the capacitance section 33 can be mounted as the inverter 47 in the electric vehicle B as shown in FIG.

Note that the inverter A of the present embodiment can be applied not only to the hybrid electric vehicle (HEV) described above, but also to various power conversion application products such as an electric vehicle (EV), an electric bicycle, a generator, and a solar battery.

1 Capacitor Element 1a Capacitor Element of First Element Row 11 1b Capacitor Element of Second Element Row 12 2 Bus Bar 3 Insulating Member 5, 6 Connection Portion 7 Filling Resin 8 Case 11 First Element Row 12 Second Element Row 21 First Bus Bar 21a first busbar body 21b first branch connection portion 21c second branch connection portion 21d first external terminal 22 second busbar 22a second busbar main body 22b third branch connection portion 22c fourth branch connection portion 22d second external terminal 32 bridge Circuit 33 Capacitor 35 Booster Circuit 41 Motor 43 Engine 45 Transmission 47 Inverter 49 Power Supply 51a Front Wheel 51b Rear Wheel 53 Vehicle ECU
55 Ignition key 57 Engine ECU
100, 101 Film capacitor Film capacitor A Inverter B Electric vehicle M Motor

Claims (7)

a first element row in which a plurality of capacitor elements are arranged;
a second element row in which a plurality of capacitor elements are arranged;
a first bus bar main body, a first branch connection portion branched from the first bus bar main body and electrically connected to each capacitor element of the first element array, and each of the second element array branched from the first bus bar main body a first bus bar including a second branch connection electrically connected to the capacitor element;
a second bus bar main body, a third branch connection portion branched from the second bus bar main body and electrically connected to each capacitor element of the first element row, and each of the second element rows branched from the second bus bar main body a second bus bar including a fourth branch connection electrically connected to the capacitor element;
an insulating member that electrically insulates the first busbar and the second busbar,
In a state in which the first bus bar and the second bus bar are connected to each capacitor element of the first element row and each capacitor element of the second element row, the insulating member is provided with the first bus bar body and the second bus bar. It is sandwiched between the main body of the busbar and
The length of the first branch connection and the length of the second branch connection are the same,
A film capacitor, wherein the length of the third branch connection portion and the length of the fourth branch connection portion are the same. The first busbar main body and the second busbar main body are band-shaped,
the first branch connection portion and the third branch connection portion are located on the first end side of the first bus bar main body and the second bus bar main body, respectively;
2. The film capacitor according to claim 1, wherein said second branch connection portion and said fourth branch connection portion are located on the second end side of said first bus bar main body and said second bus bar main body, respectively. The first busbar main body and the second busbar main body are U-shaped,
3. The film capacitor according to claim 2, wherein the second ends of said first busbar body and said second busbar body are positioned between said first element row and said second element row. The first branch connection portion has a rectangular plate shape, and the first side portion of two side portions parallel to each other is connected to the first bus bar main body, and the second side portion is connected to each of the first element rows. connected to a capacitor element,
The third branch connection portion has a rectangular plate-like shape, a first side portion of two sides parallel to each other is connected to the second bus bar main body, and a second side portion is connected to each of the first element rows. A film capacitor according to any one of claims 1 to 3, connected to a capacitor element. The second branch connection portion has a plurality of rectangular plate shapes, and each of the first side portions of two side portions parallel to each other is connected to the first bus bar main body, and each of the second side portions is connected to the second side portion. connected to each capacitor element in the element row,
The fourth branch connection portion has a plurality of rectangular plate shapes, and each of the first side portions of two side portions parallel to each other is connected to the second bus bar main body, and each of the second side portions is connected to the second side portion. 5. The film capacitor according to claim 1, connected to each capacitor element of an element row. comprising a bridge circuit composed of switching elements and a capacitor connected to the bridge circuit,
An inverter, wherein the capacitive section includes the film capacitor according to any one of claims 1 to 5. A power supply, an inverter connected to the power supply, a motor connected to the inverter, and wheels driven by the motor,
An electric vehicle, wherein the inverter is the inverter according to claim 6 .

Images