JP2006196678A - Capacitor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacitor device capable of performing self discharging with excellent heat radiation. <P>SOLUTION: A conductive resin is used as a resin section 48 for filling the capacitor element 50. The resin section 48 is allowed to be conductive, thus discharging charge accumulated in the capacitor within fixed time when power is interrupted. The value of resistance between electrodes is set to several tens of kΩ. Although problems of heat radiation result since heat is centered in a resistance element if the value of the resistance element is small when mounting a discharge resistor between terminals, an increase in temperature can be restrained because the resin section 48 is relatively large and heat is radiated in a wide region. A thin resin section 46 adhering to both of a resin case 44 and a metal case 42 is preferably formed to improve heat radiation properties. The metal case 42 is cooled by wind when a vehicle drives and can appropriately emit heat by the discharge of the capacitor to the outside. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a capacitor device, and more particularly to a smoothing large-capacity capacitor device.

Japanese Patent Laid-Open No. 2-45907 (Patent Document 1) discloses that a dielectric ceramic body between two electrodes or an insulating resin to be coated is provided with conductivity and a self-discharge function is provided on the capacitor itself. A capacitor device that does not require a special circuit is disclosed.
JP-A-2-45907 JP 2002-179184 A JP 2002-154595 A JP 2004-201439 A JP-A-2-28910

  Even in the smoothing capacitor of the inverter circuit that drives the motor for automobiles, the electric charge remains even after the power supply is cut off. Therefore, the electric discharge is promptly discharged by connecting a discharge resistor for safety.

  However, in such applications, a capacitor using a ceramic body as a dielectric as disclosed in JP-A-2-45907 (Patent Document 1) is used because its withstand voltage, capacitance value, price, etc. do not match. Absent.

  In addition, a smoothing capacitor for such a use is used in which a plurality of capacitor elements are connected in parallel in order to meet the demand for high frequency high current and large capacity. Furthermore, even though it is installed inside the hood of a vehicle, it is used outdoors, requires high moisture resistance, and requires mechanical strength. Therefore, it is housed in a metal case and has a moisture-proof resin inside. Filled with. That is, the capacitor has a structure in which heat is easily trapped for protecting the element.

  Since heat is generated when discharging with the discharge resistor, in the case of a capacitor having such a structure, if the discharge resistor is not carefully positioned, the vicinity of the discharge resistor becomes hot and the discharge resistor may be burned out. . Therefore, it is necessary to prevent the temperature from rising due to heat generated by the discharge.

  The objective of this invention is providing the capacitor | condenser apparatus which can perform self-discharge with sufficient heat dissipation.

  In summary, the present invention provides a capacitor device, in which a capacitor having first and second electrodes, a case for housing the capacitor, and a gap between the capacitor and the case are filled, and the first electrode and the second electrode A first resin portion having electrical conductivity that contacts the electrode.

  Preferably, the capacitor device further includes an outer case that accommodates the case, and a second resin portion that is filled between the case and the outer case.

  Preferably, the capacitor includes a plurality of capacitor elements connected in parallel between the first and second electrodes.

  According to another aspect of the present invention, a capacitor device includes a capacitor having first and second electrodes, and a conductor connected to the first and second electrodes. The conductor includes a first bus bar connected to the first electrode, a second bus bar arranged at least partially in parallel with the first bus bar, and connected to the second electrode, and the first bus bar. And a first resin portion having electrical conductivity that contacts the second bus bar.

  Preferably, the capacitor device further includes a case for housing the capacitor, and a conductive second resin portion that fills a gap between the capacitor and the case and contacts the first electrode and the second electrode. .

  More preferably, the capacitor device further includes an exterior case that accommodates the case, and a third resin portion that is filled between the case and the exterior case.

  Preferably, the capacitor includes a plurality of capacitor elements connected in parallel between the first and second electrodes.

  According to the present invention, it is not necessary to separately provide a discharge resistance element, and heat dissipation occurs in a wide region, so that a temperature rise can be suppressed, which is advantageous in terms of heat dissipation. In addition, heat generated by discharging the capacitor can be released to the outside. Furthermore, since the case is filled with resin, it is easy to manufacture and has high structural strength.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

[Configuration of system in which capacitor device is used]
FIG. 1 is a circuit diagram showing a configuration of a motor drive system in which the capacitor device of the present invention is used. Such a motor drive system is a system mounted on, for example, an electric vehicle, a hybrid vehicle, and a fuel cell vehicle.

  The motor drive system shown in FIG. 1 includes a battery 1, a system main relay 41, a capacitor device 3, an inverter 2, a motor 40, and a motor control circuit 30.

  The battery 1 is a secondary battery such as nickel metal hydride or lithium ion. The system main relay 41 is turned on / off by a signal from the motor control circuit 30.

  Inverter 2 receives power supply potential smoothed by capacitor device 3 and drives AC motor 40. Further, the inverter 2 returns the electric power generated in the AC motor 40 due to the regenerative braking to the battery 1.

  The AC motor 40 is a motor for generating torque for driving drive wheels (not shown) of the vehicle. For example, when this motor is mounted on a hybrid vehicle, it has a function of a generator driven by an engine, and operates as an electric motor for the engine to start the engine. Also good.

  The inverter 2 is a U-phase arm UA, a V-phase arm VA, a W-phase arm WA, a current sensor 21, and an IGBT (Insulated Gate Bipolar Transistor) control that receives the output of the current sensor 21 and controls each phase arm. Circuit 20. The inverter 2 may be housed in one case as an intelligent power module (IPM).

  U-phase arm UA, V-phase arm VA, and W-phase arm WA are connected in parallel between bus bars 1 c and 1 d connected to both terminals of capacitor device 3.

  U-phase arm UA includes IGBT elements 4 and 5 connected in series, and diodes 10 and 11 connected in parallel with IGBT elements 4 and 5, respectively. The cathode of diode 10 is connected to the collector of IGBT element 4, and the anode of diode 10 is connected to the emitter of IGBT element 4. The cathode of diode 11 is connected to the collector of IGBT element 5, and the anode of diode 11 is connected to the emitter of IGBT element 5.

  V-phase arm VA includes IGBT elements 6 and 7 connected in series, and diodes 12 and 13 connected in parallel with IGBT elements 6 and 7, respectively. The cathode of diode 12 is connected to the collector of IGBT element 6, and the anode of diode 12 is connected to the emitter of IGBT element 6. The cathode of diode 13 is connected to the collector of IGBT element 7, and the anode of diode 13 is connected to the emitter of IGBT element 7.

  W-phase arm WA includes IGBT elements 8 and 9 connected in series, and diodes 14 and 15 connected in parallel to IGBT elements 8 and 9, respectively. The cathode of diode 14 is connected to the collector of IGBT element 8, and the anode of diode 14 is connected to the emitter of IGBT element 8. The cathode of diode 15 is connected to the collector of IGBT element 9, and the anode of diode 15 is connected to the emitter of IGBT element 9.

  An intermediate point of each phase arm is connected to each phase end of each phase coil of AC motor 40. That is, the AC motor 40 is a three-phase permanent magnet motor, and one end of each of the three coils of the U, V, and W phases is connected to the middle point. The other end of the U-phase coil is connected to the connection node of IGBT elements 4 and 5. The other end of the V-phase coil is connected to the connection node of IGBT elements 6 and 7. The other end of the W-phase coil is connected to the connection node of IGBT elements 8 and 9.

  The motor control circuit 30 converts the DC voltage into an AC voltage for driving the motor 40 to the inverter 2 and converts the AC voltage generated by the motor 40 into a DC voltage and returns it to the battery 1 side. Regenerative instructions are output.

[Embodiment 1]
FIG. 2 is a plan view of the capacitor device 3 of FIG.

  FIG. 3 is a cross-sectional view taken along III-III of the capacitor device 3 of FIG.

  FIG. 4 is a cross-sectional view taken along IV-IV of the capacitor device 3 of FIG.

2 to 4, the capacitor device 3 includes a metal case 42 and a case 42.
A resin case 44 housed inside, a plurality of capacitor elements 50 arranged inside the resin case 44, a metal plate 52 connected to each positive electrode of the plurality of capacitor elements 50, and a plurality of capacitor elements 50 and a metal plate 54 connected to each negative electrode. A positive terminal 1 a is connected to the metal plate 52, and a negative terminal 1 b is connected to the metal plate 54.

  Capacitor element 50 is a film capacitor using, for example, a high pressure-resistant film such as polyester or polypropylene as a dielectric.

  Each of the capacitor elements 50 is formed by winding a base film material obtained by depositing a metal thin film. After winding, the positive and negative electrode metal thin films are exposed at both ends. Therefore, a sprayed metal called metallicon is formed on the exposed electrode thin film, and the metallicon part and the metal plates 52 and 54 are soldered. Connect with. A plurality of capacitor elements 50 are connected in parallel between the metal plates 52 and 54.

  The metal case 42 is made of, for example, aluminum die casting that can be mass-produced. The metal case 42 protects the internal capacitor element 50 from external impacts and the like. Further, when combined with the inverter 2, it also has an effect as a shield for preventing electromagnetic noise generated from the inverter 2 from leaking to the outside.

  The resin case 44 is made of a resin having good insulation and moisture resistance. For example, a PPS resin is used. The resin case 44 is used to ensure insulation between the metal case 42 disposed on the outside of the resin case 44 and the internal capacitor element 50 and to protect the capacitor element 50 from moisture. Since the case is filled with resin, it is easy to manufacture and structurally strong.

  Furthermore, in order to further ensure the moisture resistance of the capacitor element 50 and improve the mechanical strength against vibration, the resin case 44 is filled with an epoxy resin or the like and a resin portion 48 is formed.

  The terminals 1a and 1b protrude upward from the resin portion 48 filled in the resin case 44, and a bolt mounting hole is provided at each tip portion.

  As the resin part 48, for example, an epoxy resin in which conductive powder is dispersed can be used. By adjusting the density of the conductive powder, the resistance value between the electrodes can be adjusted to several tens of kΩ. As an example of the conductive powder, flaky silver powder, spherical silver powder or carbon powder can be used. The conductive powder is also called a conductive filler.

  By making the resin portion 48 conductive, the charge accumulated in the capacitor can be discharged within a certain time when the power is shut off. Since this discharge may be relatively slow, the resistance value between the electrodes is set to several tens of kΩ.

  When a discharge resistor is provided between the terminals, if the size of the resistance element is small, heat is concentrated on the resistance element, causing a problem of heat dissipation. However, the resin part 48 is relatively large and the heat dissipation occurs in a wide area. Therefore, the temperature rise can be suppressed, which is advantageous in terms of heat dissipation.

  The capacitor element of the present invention further includes a resin portion 46 formed by being filled between the resin case 44 and the metal case 42. The metal case 42 is also effective for increasing the strength of the capacitor device. When the resin case 44 is accommodated in the metal case 42, the resin case 44 and the metal case 42 are in point contact at several points unless the resin portion 46 is provided. Most of the space between the resin case 44 and the metal case 42 performs heat transfer with a thin air layer interposed therebetween, so heat transfer is not good.

  For this reason, the thin resin part 46 closely_contact | adhered to both the resin case 44 and the metal case 42 is formed, and the heat dissipation is improved. Since the metal case 42 is cooled by the traveling wind when the vehicle travels, the heat generated by the discharge of the capacitor can be well discharged to the outside.

  Preferably, heat can be released to the outside more satisfactorily by using a high thermal conductive resin as the resin portion 46. For example, since the insulation between the internal capacitor element and the metal case 42 is ensured by the resin case 44, if the metal powder is dispersed in the resin portion 46, the thermal conductivity of the resin portion 46 itself is improved. The heat radiation from the capacitor element 50 to the outside of the metal case 42 can be further improved.

[Embodiment 2]
In the first embodiment, the filling resin inside the capacitor device is made conductive, thereby forming a discharge resistor for discharging the accumulated charge at this portion.

  On the other hand, in the second embodiment, the capacitor device has a bus bar attached to the terminal portion and discharges at the bus bar portion.

  FIG. 5 is a diagram showing a power module connected to the capacitor device shown in FIGS.

  Referring to FIG. 5, module IPM includes circuit boards 61, 62 and 63 provided on cooler 60, IGBT elements 4 and 5 mounted on the circuit board, IGBT elements 4 and 5 and an adjacent board. And wires 64 and 65 are connected to each other. The bus bar 1 c is connected to the substrate 61, and the bus bar 1 d is connected to the substrate 63. The bus bars 1c and 1d constitute a bus bar unit BB. This bus bar unit BB has a one-piece structure in which a part thereof is covered with resin.

  The other ends of the bus bars 1c and 1d included in the bus bar unit BB are connected to the terminals 1a and 1b in FIGS.

  6 is a cross-sectional view taken along the line VI-VI in FIG.

  Referring to FIG. 6, bus bars 1c and 1d are positive and negative metal conductors arranged inside a device connected to a DC power source, and generally have an insulating layer 70 interposed to reduce inductance. Are stacked. In the second embodiment, the bus bars 1c and 1d are connected by conductive resins 71 and 73. The conductive resins 71 and 73 function as a discharge resistance.

  The conductive resins 71 and 73 and the bus bars 1c and 1d are covered with an insulating coating 72. Therefore, the heat dissipation can be improved by bringing the bus bar unit BB into close contact with the metal case 42 cooled by the traveling wind.

  Note that at least a part of the bus bars 1c and 1d may be molded with a conductive resin having a resistance value adjusted in the same manner as in the first embodiment.

  Also in the second embodiment, it is possible to realize a discharge resistance with good heat dissipation.

  2 to 3, the resin filling the capacitor element may be made conductive, and the configuration shown in FIG. 6 may be used for the parallel portion of the bus bar. In this case, the resistance value of the conductive resin is adjusted so that the combined resistance value of the two resistors is several tens of kΩ. In this way, the heat generating portion can be further dispersed, and the temperature rise can be suppressed.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is the circuit diagram which showed the structure of the motor drive system in which the capacitor | condenser apparatus of this invention is used. It is a top view of the capacitor | condenser apparatus 3 of FIG. It is sectional drawing in III-III of the capacitor | condenser apparatus 3 of FIG. It is sectional drawing in IV-IV of the capacitor | condenser apparatus 3 of FIG. It is the figure which showed the power module connected to the capacitor | condenser apparatus shown in FIGS. It is sectional drawing in the VI-VI cross section of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Battery, 1a, 1b terminal, 1c, 1d Bus bar, 2 Inverter, 3 Capacitor device, 4-9 IGBT element, 10-15 Diode, 20 IGBT control circuit, 21 Current sensor, 30 Motor control circuit, 40 Motor, 41 System Main relay, 42 Metal case, 44 Resin case, 46, 48 Resin part, 50 Capacitor element, 52, 54 Metal plate, 60 Cooler, 61, 62, 63 Circuit board, 64, 65 Wire, 70 Insulating layer, 71, 73 conductive resin, 72 insulation coating, BB bus bar unit, IPM module, UA U phase arm, VA V phase arm, WA W phase arm.

Claims (7)

A capacitor having first and second electrodes;
A case for housing the capacitor;
A capacitor device comprising: a conductive first resin portion that fills a gap between the capacitor and the case and contacts the first electrode and the second electrode. An outer case for housing the case;
The capacitor device according to claim 1, further comprising a second resin portion filled between the case and the exterior case. The capacitor is
The capacitor device according to claim 1, comprising a plurality of capacitor elements connected in parallel between the first and second electrodes. A capacitor having first and second electrodes;
A conductor connected to the first and second electrodes,
The conductor is
A first bus bar connected to the first electrode;
A second bus bar disposed at least partially in parallel with the first bus bar and connected to the second electrode;
A capacitor device comprising: a first resin portion having electrical conductivity that contacts the first bus bar and the second bus bar. A case for housing the capacitor;
5. The capacitor device according to claim 4, further comprising a conductive second resin portion that fills a gap between the capacitor and the case and contacts the first electrode and the second electrode. 6. An outer case for housing the case;
The capacitor device according to claim 5, further comprising a third resin portion filled between the case and the exterior case. The capacitor is
The capacitor device according to claim 4, comprising a plurality of capacitor elements connected in parallel between the first and second electrodes.

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