Power conversion device

Abstract

To provide a power conversion device in which a temperature increase of an electronic component is suppressed while keeping a small size.SOLUTION: A power conversion device includes: an electronic component having a main body part as a heat generator, a first electrode electrically connected to one side of the main body part, and a second electrode electrically connected to the other side of the main body part, in which the first electrode, the main body part, and the second electrode are stacked in this order; and a cooler that cools the electronic component. The first electrode has a first electrode main body part connected to the main body part, and a first connection terminal connected to the first electrode main body part. The second electrode has a second electrode main body part connected to the main body part, and a second connection terminal connected to the second electrode main body part. In a case where the heat conduction from the first electrode to the cooler is larger than the heat conduction from the second electrode to the cooler, a cross-sectional area of the second connection terminal is larger than a cross-sectional area of the first connection terminal. In a case where the heat conduction from the second electrode to the cooler is larger than the heat conduction from the first electrode to the cooler, the cross-sectional area of the first connection terminal is larger than the cross-sectional area of the second connection terminal.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a power conversion device. [Background technology]

[0002] Electric vehicles using a motor as a drive source, such as hybrid vehicles, plug-in hybrid vehicles, electric vehicles, and fuel cell vehicles, are equipped with power conversion devices such as an inverter for driving the drive motor and a converter for stepping up and down the power supply voltage of a battery. Since the power conversion device needs to be installed in a limited space in order to ensure a trunk and living space for passengers inside the electric vehicle, the power conversion device is required to be a small component. In addition, the power conversion device installed in the vehicle is connected to a heat source such as an engine, a transmission, or a motor, and therefore is required to have high durability against heat.

[0003] Power conversion devices such as inverters and converters often include a capacitor having a capacitor element that smoothes a direct current supplied from an external direct current power source. The capacitor is one of the electronic components included in the power conversion device. Since a ripple current flows through the capacitor, the capacitor consumes power and generates heat. In addition, since the capacitor is connected to other components via a bus bar, heat is transferred from the other components to the capacitor via the bus bar, and the transferred heat may cause the capacitor to become hot. A temperature rise in the capacitor shortens the life of the capacitor element, so measures to prevent the temperature rise in the capacitor are an issue.

[0004] A configuration that implements measures to prevent temperature rise in the capacitor has been disclosed (see, for example, Patent Document 1). In the structure disclosed in Patent Document 1, the thermal resistance of the bus bar at the point connected to the capacitor is increased. With this configuration, the amount of heat transferred from the bus bar to the capacitor is reduced, and therefore the temperature rise in the capacitor can be suppressed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2022-128162 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the above-mentioned Patent Document 1, the thermal resistance of the busbar at the portion connected to the capacitor is increased, so that the temperature rise of the capacitor can be suppressed. However, because the thermal resistance of the busbar at the portion connected to the capacitor is large, there is a problem that it is difficult to cool the capacitor via the busbar. In addition, although it is possible to suppress the transfer of heat from the busbar to the capacitor, there is a problem that if the busbar itself generates a lot of heat, the heat of the busbar causes the capacitor to become hot.

[0007] Therefore, an object of the present disclosure is to obtain a power conversion device that suppresses temperature rise in electronic components while maintaining a small size. [Means for solving the problem]

[0008] The power conversion device of the present disclosure includes a main body portion which is a heating element, a first electrode electrically connected to one side of the main body portion, and a second electrode electrically connected to the other side of the main body portion opposite to the one side, and includes electronic components stacked in the order of the first electrode, main body portion, and second electrode, and a cooler which cools the electronic components, and the first electrode includes a first electrode main body portion connected to the main body portion, and a first connection terminal connected to the first electrode main body portion and connected to another component on the side opposite to the first electrode main body portion, and the second electrode includes a second electrode main body portion connected to the main body portion, and a first connection terminal connected to the second electrode main body portion. and has a second connection terminal connected to another component on the side opposite to the second electrode main body, and when the thermal conduction from the first electrode to the cooler is greater than the thermal conduction from the second electrode to the cooler, the cross-sectional area of ​​the second connection terminal in a direction perpendicular to the direction of current flow is greater than the cross-sectional area of ​​the first connection terminal in a direction perpendicular to the direction of current flow, and when the thermal conduction from the second electrode to the cooler is greater than the thermal conduction from the first electrode to the cooler, the cross-sectional area of ​​the first connection terminal in a direction perpendicular to the direction of current flow is greater than the cross-sectional area of ​​the second connection terminal in a direction perpendicular to the direction of current flow. Effect of the Invention

[0009] According to the power conversion device of the present disclosure, when the thermal conduction from the first electrode to the cooler is greater than the thermal conduction from the second electrode to the cooler, the cross-sectional area of ​​the second connection terminal in the direction perpendicular to the current flow is greater than the cross-sectional area of ​​the first connection terminal in the direction perpendicular to the current flow, and when the thermal conduction from the second electrode to the cooler is greater than the thermal conduction from the first electrode to the cooler, the cross-sectional area of ​​the first connection terminal in the direction perpendicular to the current flow is greater than the cross-sectional area of ​​the second connection terminal in the direction perpendicular to the current flow. Therefore, without adding any new components, the amount of heat generated by the first connection terminal of the first electrode or the second connection terminal of the second electrode, which has less thermal conduction to the cooler and is difficult to cool, is reduced, so that the amount of heat transmitted to the electronic components can be reduced. Since the amount of heat transmitted to the electronic components is reduced, a power conversion device that suppresses the temperature rise of the electronic components while maintaining a small size can be obtained. In addition, when the temperature of other components connected via the first connection terminal and the second connection terminal is lower than that of the electronic components, the first connection terminal or the second connection terminal has a portion with a large cross-sectional area, so that the heat of the electronic components can be efficiently dissipated to the other components. Moreover, heat transferred from the outside to the electronic component via air or the like can also be efficiently dissipated to other components via the first connection terminal or the second connection terminal. [Brief description of the drawings]

[0010] [Figure 1] 1 is a plan view showing an outline of a power conversion device according to a first embodiment. [Diagram 2] 2 is a cross-sectional view of the power converter taken along the line AA in FIG. 1. [Diagram 3] 2 is a cross-sectional view of a main part of the power conversion device taken along the line BB in FIG. 1. [Figure 4] 2 is a cross-sectional view of a main part of another power converter taken along the line BB in FIG. 1. [Diagram 5] 1 is a diagram illustrating an example of an installation state of a power conversion device according to a first embodiment. [Figure 6] FIG. 11 is a plan view showing an outline of a power conversion device according to a second embodiment. [Figure 7] 11 is a plan view showing an outline of a positive bus bar of a power converter according to a second embodiment. FIG. [Figure 8] FIG. 11 is a side view showing an outline of a positive bus bar of a power converter according to a second embodiment. [Figure 9] 7 is a cross-sectional view of the power converter taken along the CC cross section in FIG. 6. [Figure 10] FIG. 11 is a plan view showing an outline of a power conversion device according to a third embodiment. [Figure 11] 11 is a cross-sectional view of the power converter taken along the line DD in FIG. 10. [Figure 12] 11 is a cross-sectional view of a main part of the power converter taken along the E-E cross section of FIG. 10. [Figure 13] FIG. 11 is a cross-sectional view showing an outline of a power conversion device according to a fourth embodiment. [Figure 14] 13 is a side view showing an outline of a rapid discharge resistor of a power conversion device according to a fourth embodiment. FIG. [Figure 15] 15 is a cross-sectional view of a main part of the rapid discharge resistor taken along the line FF in FIG. 14. [Figure 16] 13 is a cross-sectional view showing an outline of a substrate of a power converter according to a fifth embodiment. FIG. [Figure 17] 17 is a cross-sectional view of the substrate of the power converter taken along the line GG in FIG. 16. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, a power conversion device according to an embodiment of the present disclosure will be described with reference to the drawings. Note that the same or corresponding members and parts in each drawing will be described with the same reference numerals.

[0012] Embodiment 1 Fig. 1 is a plan view showing an outline of a power converter 1 according to embodiment 1, with a substrate 5 removed, Fig. 2 is a cross-sectional view of the power converter 1 taken along the AA cross section in Fig. 1, Fig. 3 is a cross-sectional view of a terminal 45 for connecting other components, which is a main part of the power converter 1, taken along the BB cross section in Fig. 1, Fig. 4 is a cross-sectional view of a terminal 45 for connecting other components, which is a main part of another power converter 1, taken along the BB cross section in Fig. 1, and Fig. 5 is a diagram showing an example of an installation state of the power converter 1. The power converter 1 is a device that converts an input current from DC to AC, AC to DC, or an input voltage to a different voltage.

[0013] As shown in FIG. 2, the power conversion device 1 includes a semiconductor module 3, a capacitor 4, a substrate 5, a rapid discharge resistor 6 (not shown in FIG. 1 and FIG. 2), and a cooler 2. The cooler 2 accommodates the semiconductor module 3, the capacitor 4, the substrate 5, and the rapid discharge resistor 6. The power conversion device 1 in this embodiment is a device that converts DC power input from a terminal 45 for connecting other components of the capacitor 4 connected to a DC power source 7 and smoothed by the capacitor 4, and outputs the converted power by the semiconductor module 3. This embodiment shows the power conversion device 1 that outputs three-phase AC, and as shown in FIG. 1, the semiconductor module is composed of three semiconductor modules 3 corresponding to each phase. The configuration of the power conversion device 1 is not limited to this, and the power conversion device 1 may be a device that converts an input current from AC to DC.

[0014] <Cooler 2> The cooler 2 is made of a metal such as aluminum. As shown in FIG. 2, the cooler 2 is formed, for example, in a bottomed cylindrical shape. The cooler 2 has a first surface 2b to which the semiconductor module 3 is thermally connected, and a second surface 2c that is parallel to the first surface 2b and to which the capacitor 4 is thermally connected. A plate-shaped forced cooling section 21 is provided in the portion of the cooler 2 where the first surface 2b is formed. A flow path 22 for cooling the first surface 2b is provided on the rear surface side of the rear side of the forced cooling section 21. The front surface, which is one surface of the forced cooling section 21, becomes the first surface 2b. The portion of the cooler 2 where the flow path 22 is provided is a flow path forming section 23. The flow path forming section 23 is provided on the other surface side of the forced cooling section 21. A coolant flows through the flow path 22. For example, a liquid such as water or ethylene glycol liquid, or a gas such as air is used as the coolant. Here, directions are defined. A direction opposite to the normal direction of first surface 2b is defined as the anti-normal direction, a specific direction parallel to first surface 2b is defined as the first direction, and a direction parallel to first surface 2b and perpendicular to the first direction is defined as the second direction. In the figure, the X1 direction is one side of the first direction, the X2 direction is the other side of the first direction, the Y direction is the second direction, the Z1 direction is the normal direction, and the Z2 direction is the anti-normal direction.

[0015] The forced cooling unit 21 is made of a metal such as aluminum like the main body of the cooler 2, but is not limited thereto and may be made of a resin member having excellent thermal conductivity. A plurality of cooling fins may be provided on the rear surface of the forced cooling unit 21 in an area overlapping with the semiconductor module 3 when viewed in the normal direction. As shown in FIG. 1, the flow path forming unit 23 has refrigerant inlets and outlets 24a, 24b. The refrigerant inlets and outlets 24a, 24b are inlets through which the refrigerant flows into the flow path 22 or flows out from the flow path 22. The refrigerant inlets and outlets 24a, 24b have portions protruding from the outer wall surface of the cooler 2.

[0016] The refrigerant flows, for example, through the refrigerant inlet / outlet 24a, the flow path 22, and the refrigerant inlet / outlet 24b in this order. The refrigerant inlet / outlet 24a is disposed closer to the condenser 4 than the refrigerant inlet / outlet 24b when viewed in the normal direction. With this configuration, a low-temperature refrigerant flows on the side of the refrigerant inlet / outlet 24a before cooling the semiconductor module 3, so that the side of the second surface 2c disposed adjacent to the first surface 2b is also efficiently cooled. Since the second surface 2c is cooled, the condenser 4 thermally connected to the second surface 2c can be cooled.

[0017] As shown in FIG. 2, the second surface 2c faces the normal direction and is disposed on one side of the first surface 2b in the first direction and on the side opposite the normal direction from the first surface 2b. The cooler has a step 2a between the first surface 2b and the second surface 2c. The flow path 22 is disposed on the other side of the step 2a in the first direction. With this configuration, the step 2a can be provided so that the positive power terminal 42a1 and the negative power terminal 42b1 of the condenser bus bar 42 protruding from the capacitor 4 are aligned with the normal direction positions of the semiconductor module bus bar 33 protruding from the semiconductor module 3. Therefore, the length of the condenser bus bar 42 can be shortened. Since the length of the condenser bus bar 42 is shortened, the capacitor element 41 and the semiconductor module 3 can be connected with low wiring inductance, and the occurrence of excess loss in the condenser bus bar 42 connecting the capacitor element 41 and the semiconductor module 3 can be suppressed.

[0018] Furthermore, since flow path 22 is disposed in the surplus space on the opposite normal side of first surface 2b and on the other side of step 2a in the first direction, the height of power converter 1 is reduced, and power converter 1 can be made more compact. Furthermore, since both refrigerant inlets 24a, 24b are arranged on the other side of step 2a in the first direction, power converter 1 can be made more compact. Furthermore, refrigerant inlet / outlet 24b is passed through by refrigerant heated by heat from semiconductor module 3, by disposing refrigerant inlet / outlet 24b at a position away from condenser 4 and disposing refrigerant inlet / outlet 24a on the side closer to condenser 4, condenser 4 can be cooled efficiently.

[0019] <Semiconductor module 3> The semiconductor module 3 includes a module body 3a housing one or more semiconductor elements 31, a semiconductor module bus bar 33, an output terminal 38, and a plurality of control terminals (not shown). The semiconductor module bus bar 33, the output terminal 38, and the control terminal are provided protruding outward from the module body 3a. The portion of the module body 3a shown in FIG. 1 is a sealing resin 35 surrounding the semiconductor element 31. The semiconductor module bus bar 33, the output terminal 38, and the control terminal are made of, for example, copper, which has a low electrical resistivity and excellent conductivity. The semiconductor module bus bar 33 includes a positive bus bar 33a and a negative bus bar 33b, and the capacitor bus bar 42 includes a positive bus bar 42a and a negative bus bar 42b. The positive bus bar 33a is electrically connected to a positive power terminal 42a1 of the positive bus bar 42a, and the negative bus bar 33b is electrically connected to a negative power terminal 42b1 of the negative bus bar 42b. The number of semiconductor elements 31 may be one or more.

[0020] <Substrate 5> The power conversion device 1 includes a substrate 5 on which a control circuit for controlling the semiconductor module 3 is mounted. The substrate 5 and the semiconductor module 3 are connected by a plurality of control terminals (not shown) of the semiconductor module 3. The substrate 5 is provided on the normal direction side of the capacitor 4 and the semiconductor module 3. The substrate 5 is disposed so as to cover at least a portion of each of the capacitor 4 and the semiconductor module 3 when viewed in the normal direction.

[0021] <Electronic components> The power conversion device 1 has an electronic component that has a heat generating body and generates heat during operation. The cooler 2 cools the electronic component. The electronic component included in the power conversion device 1 in this embodiment is a capacitor 4. The electronic component is not limited to the capacitor 4. An example in which the power conversion device 1 has an electronic component other than the capacitor 4 will be described later.

[0022] The electronic component has a main body portion which is a heat generating body, a first electrode electrically connected to one side of the main body portion, and a second electrode electrically connected to the other side opposite to the one side of the main body portion, and is laminated in the order of the first electrode, the main body portion, and the second electrode. The first electrode has a first electrode main body portion connected to the main body portion, and a first connection terminal connected to the first electrode main body portion and connected to another component on the opposite side to the first electrode main body portion. The second electrode has a second electrode main body portion connected to the main body portion, and a second connection terminal connected to the second electrode main body portion and connected to another component on the opposite side to the second electrode main body portion. When the thermal conduction from the first electrode to the cooler 2 is greater than the thermal conduction from the second electrode to the cooler 2, the cross-sectional area of ​​the second connection terminal in a direction perpendicular to the direction of current flow is greater than the cross-sectional area of ​​the first connection terminal in a direction perpendicular to the direction of current flow, and when the thermal conduction from the second electrode to the cooler is greater than the thermal conduction from the first electrode to the cooler 2, the cross-sectional area of ​​the first connection terminal in a direction perpendicular to the direction of current flow is greater than the cross-sectional area of ​​the second connection terminal in a direction perpendicular to the direction of current flow.

[0023] By configuring in this way, the amount of heat transferred to the electronic components can be reduced because the amount of heat generated by the first connection terminal of the first electrode or the second connection terminal of the second electrode, which has low thermal conduction to the cooler 2 and is difficult to cool, is reduced without adding any new components. Since the amount of heat transferred to the electronic components is reduced without adding any new components, it is possible to obtain a power conversion device that suppresses the temperature rise of the electronic components while maintaining a small size. In addition, when the temperature of other components connected via the first connection terminal and the second connection terminal is lower than that of the electronic components, the first connection terminal or the second connection terminal has a portion with a large cross-sectional area, so that the heat of the electronic components can be efficiently dissipated to the other components. In addition, heat transferred from the outside to the electronic components via air or the like can also be efficiently dissipated to the other components via the first connection terminal or the second connection terminal.

[0024] <Capacitor 4> The capacitor 4, which is an electronic component, will be described in detail below. The capacitor 4 has one or more capacitor elements 41, and a positive bus bar 42a and a negative bus bar 42b that are capacitor bus bars 42 connected to the capacitor elements 41. The main body of the electronic component is one or more capacitor elements 41, and the first electrode is the positive bus bar 42a and the second electrode is the negative bus bar 42b. The first electrode may be the negative bus bar 42b and the second electrode may be the positive bus bar 42a. The capacitor 4 further has a case 44 that houses the capacitor element 41, the positive bus bar 42a, and the negative bus bar 42b. The case 44 is filled with a sealing resin 43. The sealing resin 43 is an insulating member made of epoxy resin or the like.

[0025] The capacitor element 41 smoothes the DC power. The capacitor element 41 has electrodes 48 on both ends. Each of the electrodes 48 is a positive electrode 48a or a negative electrode 48b. In this embodiment, the positive electrode 48a is provided on the normal side of the capacitor element 41, and the negative electrode 48b is provided on the opposite side to the normal direction, but this is not limiting, and the negative electrode 48b may be provided on the normal side and the positive electrode 48a on the opposite side to the normal direction.

[0026] Capacitor element 41 is a film capacitor having a laminated structure in which metal foil and resin film serving as internal electrodes are wound into a roll. Capacitor element 41 has electrodes 48 on end faces in a normal direction and an opposite direction to the normal direction intersecting a first direction in which the metal foil is laminated. Generally, film capacitors have a higher withstand voltage than other types of capacitors, so by using a film capacitor for capacitor element 41, power conversion device 1 can be used for vehicle applications that require high withstand voltage.

[0027] In this embodiment, case 44 houses three capacitor elements 41. In Fig. 1, the outline of capacitor element 41 is indicated by a dashed line. Each of the three capacitor elements 41 is connected to each of the three semiconductor modules 3. The number of capacitor elements 41 included in capacitor 4 is not limited to three. A plurality of semiconductor modules 3 may be connected to one capacitor element 41, and a plurality of capacitor elements 41 may be connected to one semiconductor module 3.

[0028] The case 44 is made of aluminum by die casting, for example. In this embodiment, as shown in FIG. 2, the case 44 is formed in a bottomed cylindrical shape. The bottom wall 44a of the case 44 is formed in a rectangular shape, for example. The case 44 has an opening 49 which is an open portion on the side opposite to the bottom wall 44a of the case 44. The opening 49 faces the substrate 5. The capacitor bus bar 42 protrudes from the sealing resin 43 at the opening 49. In this embodiment, the case 44 is disposed so that the opening 49 faces the normal direction, and the capacitor bus bar 42 protrudes from the sealing resin 43 in the normal direction. The arrangement of the case 44 is not limited thereto, and the case 44 may be disposed so that the opening 49 faces the other side of the first direction so that the capacitor bus bar 42 protrudes from the sealing resin 43 to the semiconductor module 3 side, as described later.

[0029] The outer surface of the bottom wall 44a of the case 44 and the second surface 2c of the cooler 2 are thermally connected. The thermal connection is not limited to the case where the bottom wall 44a and the second surface 2c are connected through direct contact. The bottom wall 44a and the second surface 2c may be thermally connected via a heat transfer member such as grease or a heat dissipation sheet. By thermally connecting the case 44 to the cooler 2, the capacitor element 41 can dissipate heat from the side of the bottom wall 44a of the case 44, thereby improving the heat dissipation performance of the capacitor element 41.

[0030] The capacitor bus bar 42 is made of, for example, copper having a low electrical resistivity and excellent conductivity. The positive bus bar 42a has a first electrode body portion 42c1 connected to the positive electrode 48a of the capacitor element 41, and a first connection terminal 45a connected to the first electrode body portion 42c1 and connected to another component on the side opposite to the first electrode body portion 42c1. The negative bus bar 42b has a second electrode body portion 42c2 connected to the negative electrode 48b of the capacitor element 41, and a second connection terminal 45b connected to the second electrode body portion 42c2 and connected to another component on the side opposite to the second electrode body portion 42c2. The first connection terminal 45a and the second connection terminal 45b connected to the other component are other component connection terminals 45. The direction in which current flows through the first connection terminal 45a and the second connection terminal 45b (current path 8) is a first direction. The other component is, for example, a DC power source 7. The first electrode body portion 42c1 of the positive bus bar 42a is provided on the side of the opening 49, and the second electrode body portion 42c2 of the negative bus bar 42b is provided on the side of the bottom wall 44a. In the present embodiment, the first electrode body portion 42c1 is connected to three capacitor elements 41, and the second electrode body portion 42c2 is connected to three capacitor elements 41. The number of capacitor elements 41 to which each of the first electrode body portion 42c1 and the second electrode body portion 42c2 is connected is not limited to this.

[0031] The thermal conductivity of the metal foil of the film capacitor is higher than that of the resin film. Therefore, the thermal conductivity of the capacitor element 41 is higher in a direction intersecting the direction in which the metal foil is laminated (the axial direction of the winding core) than in the first direction in which the metal foil is laminated. When the electrode 48 and the bottom wall 44a are arranged in the opposite normal direction as in this embodiment, the thermal conductivity of the capacitor element 41 becomes high in the opposite normal direction. Therefore, by aligning the direction of high thermal conductivity of the capacitor element 41 with the direction of the heat dissipation path in which the bottom wall 44a of the case 44 is arranged, the heat of the capacitor element 41 can be dissipated to the bottom wall 44a of the case 44 more efficiently.

[0032] In this embodiment, the substrate 5 is disposed on the normal side of the capacitor 4. This is to easily electrically connect the substrate 5 and the positive bus bar 42a. The portion of the positive bus bar 42a connected to the substrate 5 is the substrate connection terminal 42a2. The positive bus bar 42a extends from the first electrode main body portion 42c1 toward the semiconductor module 3 and has a positive power terminal 42a1 connected to the semiconductor module 3. Similarly, the negative bus bar 42b extends from the second electrode main body portion 42c2 toward the semiconductor module 3 and has a negative power terminal 42b1 connected to the semiconductor module 3. The substrate connection terminal 42a2 extends in the normal direction from the positive power terminal 42a1 and is connected to the substrate 5. The substrate connection terminal 42a2 is a terminal on the substrate 5 that is connected to a driver circuit that supplies power to the semiconductor module 3.

[0033] In this embodiment, the positive bus bar 42a is provided on the side of the opening 49, and the negative bus bar 42b is provided on the side of the bottom wall 44a that is thermally connected to the cooler 2. Therefore, the distance over which heat is transferred to the cooler 2 differs between the positive electrode side and the negative electrode side of the capacitor 4. When the amount of heat transferred from the positive electrode bus bar 42a to the cooler 2 is compared with the amount of heat transferred from the negative electrode bus bar 42b to the cooler 2, the negative electrode bus bar 42b, which is closer to the cooler 2 and has a smaller thermal resistance between the negative electrode bus bar 42b and the cooler 2, transfers more heat than the positive electrode bus bar 42a. When the capacitor 4 is a film capacitor, the thermal conductivity of the resin is dominant because the film capacitor is made of a thin metal foil and a resin film. As a result, the equivalent thermal conductivity of capacitor element 41 becomes low, and so when condenser bus bar 42 generates a lot of heat and capacitor element 41 receives a large amount of heat from condenser bus bar 42, the heat cannot be sufficiently dissipated to cooler 2, and capacitor element 41 may become too hot.

[0034] In addition, the first electrode body 42c1 and the second electrode body 42c2 are electrically connected to the capacitor elements 41 inside the case 44, and therefore extend in the second direction in which the capacitor elements 41 are arranged. On the other hand, the other component connection terminal 45 is formed in a portion of the capacitor bus bar 42 that protrudes from the case 44, and is provided smaller than the first electrode body 42c1 and the second electrode body 42c2 from the viewpoint of miniaturizing the power conversion device 1 and ensuring space for arranging other components. Therefore, the other component connection terminal 45 generates more heat than the first electrode body 42c1 and the second electrode body 42c2. The heat generated in the other component connection terminal 45 is transferred to the capacitor element 41 through the first electrode body 42c1 and the second electrode body 42c2 made of copper, which has a high thermal conductivity, and this may cause the capacitor element 41 to become hot.

[0035] 3, in this embodiment, the cross-sectional area of ​​first connection terminal 45a of positive bus bar 42a, which has a small amount of heat transferred to cooler 2 and is difficult to cool, is larger than the cross-sectional area of ​​second connection terminal 45b of negative bus bar 42b, so that the amount of heat generated by first connection terminal 45a is reduced, and the amount of heat transferred to capacitor element 41 can be reduced. Since the amount of heat transferred to capacitor element 41 is reduced, the temperature rise of capacitor 4 can be suppressed. In addition, since capacitor element 41, positive bus bar 42a, and negative bus bar 42b are housed in case 44, the productivity of power conversion device 1 can be improved.

[0036] When the capacitor bus bar 42 is manufactured from a single copper plate, it is difficult to increase the thickness of only the other component connection terminal 45. In addition, since the other component and the other component connection terminal 45 are joined by screwing or welding, a joining area is required for the other component connection terminal 45, so that a certain area or more needs to be secured for the other component connection terminal 45. In this embodiment, the first connection terminal 45a of the positive bus bar 42a and the second connection terminal 45b of the negative bus bar 42b have the same thickness, and the first connection terminal 45a of the positive bus bar 42a and the second connection terminal 45b of the negative bus bar 42b have different widths in a direction perpendicular to the direction in which the current flows. Being equal means that the design lengths are the same, the difference in length is within the tolerance range, and the difference in length is within the range of manufacturing error.

[0037] With this configuration, the cross-sectional areas of the first connection terminal 45a and the second connection terminal 45b can be changed while maintaining the same thickness. In the configuration shown in FIG. 3, the cross-sectional area of ​​the first connection terminal 45a is larger than that of the second connection terminal 45b, and the amount of heat generated by the first connection terminal 45a is reduced. In FIG. 3, the direction of current flow is perpendicular to the paper surface. By increasing the width of only the first connection terminal 45a and keeping the width of the second connection terminal 45b small, the capacitor 4 can be made smaller than when the widths of both the positive bus bar 42a and the negative bus bar 42b are increased. The amount of heat generated by the second connection terminal 45b is larger than that of the first connection terminal 45a, but since the negative bus bar 42b is close to the cooler 2, the amount of heat transferred to the cooler 2 is large, and therefore the effect on the temperature of the capacitor element 41 is minor.

[0038] <DC power supply connection bus bar 71> The capacitor 4 and the DC power supply 7 are connected via a DC power supply connection bus bar 71. As the DC power supply connection bus bar 71, a DC power supply connection positive electrode bus bar 71a and a DC power supply connection negative electrode bus bar 71b are provided. One end of the DC power supply connection positive electrode bus bar 71a is electrically connected to the DC power supply 7, and the other end is electrically connected to the first connection terminal 45a of the positive electrode bus bar 42a. One end of the DC power supply connection negative electrode bus bar 71b is electrically connected to the DC power supply 7, and the other end is electrically connected to the second connection terminal 45b of the negative electrode bus bar 42b. The DC power supply connection positive electrode bus bar 71a and the DC power supply connection negative electrode bus bar 71b are thermally connected to the cooler 2 via a heat transfer member. In this embodiment, the heat transfer member is a pedestal 74 and grease 75. The heat transfer member will be described in detail later. In this embodiment, the positive bus bar 71a for connecting to a DC power supply and the negative bus bar 71b for connecting to a DC power supply are the same in size, but the sizes of the positive bus bar 71a for connecting to a DC power supply and the negative bus bar 71b for connecting to a DC power supply are not limited to this.

[0039] With this configuration, heat generated in the DC power supply connecting busbar 71 can be dissipated to the cooler 2 while ensuring insulation between the DC power supply connecting busbar 71 and the cooler 2. Therefore, the temperature of the DC power supply connecting busbar 71 is lower than that of the other component connecting terminal 45, so that heat from the condenser busbar 42 and the capacitor element 41 can be dissipated to the cooler 2 via the other component connecting terminal 45. Since the heat from the condenser busbar 42 and the capacitor element 41 is dissipated to the cooler 2, deterioration of the capacitor element 41 due to heat can be suppressed. In addition, since the cross-sectional area of ​​the first connection terminal 45a is larger than the cross-sectional area of ​​the second connection terminal 45b, heat from the positive electrode busbar 42a, which has a smaller amount of heat transfer to the cooler 2, can be dissipated to the cooler 2 via the DC power supply connecting busbar 71 in a larger amount than that from the negative electrode busbar 42b.

[0040] The first connection terminal 45a and the second connection terminal 45b are connected to another component by screwing. In the present embodiment, the other component is a bus bar 71 for connecting a DC power supply. As shown in Fig. 2, the first connection terminal 45a and the positive bus bar 71a for connecting a DC power supply are connected by a screw 72. The screw 72 is omitted in Fig. 1.

[0041] By configuring in this manner, the power conversion device 1 can be manufactured at a lower cost than when connection is made by welding. In addition, since the other component connection terminals 45 and the DC power supply connection bus bar 71 can be connected over a large area, the contact thermal resistance between the other component connection terminals 45 and the DC power supply connection bus bar 71 can be reduced. Since the contact thermal resistance between the other component connection terminals 45 and the DC power supply connection bus bar 71 is reduced, more heat can be dissipated from the condenser 4 to the cooler 2 via the DC power supply connection bus bar 71.

[0042] The connection between the first connection terminal 45a and the second connection terminal 45b and other components is not limited to the screw 72. The first connection terminal 45a and the second connection terminal 45b may be connected to the DC power supply connection bus bar 71, which is another component, by welding. As shown in FIG. 4, the portion between the first connection terminal 45a and the DC power supply connection positive electrode bus bar 71a is a welded portion 73 where the first connection terminal 45a and the DC power supply connection positive electrode bus bar 71a are welded. The portion between the second connection terminal 45b and the DC power supply connection negative electrode bus bar 71b is a welded portion 73 where the second connection terminal 45b and the DC power supply connection negative electrode bus bar 71b are welded. With this configuration, the contact thermal resistance between the first connection terminal 45a and the second connection terminal 45b and the DC power supply connection bus bar 71 can be reduced. Since the contact thermal resistance between the first connection terminal 45a and the second connection terminal 45b and the bus bar 71 for connecting a DC power source is reduced, it is possible to improve the effect of dissipating heat from the first connection terminal 45a and the second connection terminal 45b to the bus bar 71 for connecting a DC power source. Furthermore, compared to connection by screws, the first connection terminal 45a and the second connection terminal 45b can be connected to the bus bar 71 for connecting a DC power source in a space-saving manner.

[0043] In this embodiment, the heat transfer member is an insulating material and grease 75 provided in layers. As shown in FIG. 2, the insulating material is a resin base 74. The DC power supply connection bus bar 71 is fixed to the base 74 by, for example, adhesion or screws. The base 74 is thermally connected to the cooler 2 by screws via the grease 75. The DC power supply connection bus bar 71 and the base 74 may be fixed to the cooler 2 by screws as a whole. The grease 75 can be made thinner by pressing the base 74 against the cooler 2 by screws or the like. Since the grease 75 is made thinner, the contact thermal resistance between the base 74 and the cooler 2 can be made smaller than when a heat transfer member other than the grease 75 is used. Since the contact thermal resistance between the base 74 and the cooler 2 is reduced, the heat dissipation from the DC power supply connection bus bar 71 to the cooler 2 can be improved.

[0044] When grease 75 is used in this manner, since grease 75 has good adhesion to base 74 and cooler 2, a gap is unlikely to occur between base 74 and cooler 2, and therefore the contact thermal resistance between base 74 and cooler 2 can be reduced. In addition, by reducing the thickness of base 74, it is possible to further improve the heat dissipation from DC power supply connection bus bar 71 to cooler 2. The heat transfer member is not limited to an insulating material and grease 75, and may be another member such as a heat dissipation sheet.

[0045] The positive bus bar 42a is disposed so as to cover the upper surface of the capacitor element 41. With this configuration, heat transferred from other components around the capacitor 4 to the capacitor 4 via the air is dissipated from the first electrode main body portion 42c1 of the positive bus bar 42a to the cooler 2 via the first connection terminal 45a and the positive bus bar 71a for connecting a DC power supply, and is not transferred to the capacitor element 41. In this embodiment, the substrate 5 is disposed in the normal direction of the capacitor 4. Components that generate heat are disposed on the surface of the substrate 5 in the normal direction, but the heat from the heated components is shielded by the substrate 5.

[0046] <Yコンデンサ46、47> In this embodiment, a Y capacitor for noise removal is electrically connected to each of the first connection terminal 45a of the positive bus bar 42a and the second connection terminal 45b of the negative bus bar 42b. As shown in FIG. 1, a Y capacitor 46 is connected to the first connection terminal 45a, and a Y capacitor 47 is connected to the second connection terminal 45b. The Y capacitors 46, 47 receive heat from the capacitor bus bar 42, similar to the capacitor element 41. There is a risk that the Y capacitors 46, 47 will exceed their heat resistance temperature due to the heat received. Since the Y capacitors 46, 47 do not generate heat themselves, the temperatures of the Y capacitors 46, 47 are determined by the heat received from the outside.

[0047] In this embodiment, the cross-sectional area of ​​the first connection terminal 45a of the positive bus bar 42a, which transfers less heat to the cooler 2 and is therefore less likely to be cooled, is larger than the cross-sectional area of ​​the second connection terminal 45b of the negative bus bar 42b, and therefore the amount of heat generated by the first connection terminal 45a is small. Since the Y capacitor 46 is connected to the first connection terminal 45a, which has a large cross-sectional area and generates less heat, the temperature of the Y capacitor 46 can be effectively reduced. Since the second connection terminal 45b of the negative bus bar 42b transfers a large amount of heat to the cooler 2, it is possible to suppress a rise in temperature of the Y capacitor 47 connected to the second connection terminal 45b.

[0048] In the present embodiment, the Y capacitors 46, 47 are housed in the case 44, and the Y capacitors are connected to the first connection terminal 45a of the positive bus bar 42a and the second connection terminal 45b of the negative bus bar 42b inside the case 44. With this configuration, the Y capacitors 46, 47 and the capacitor element 41 are housed in the same case 44, which reduces dead space in the capacitor 4 and allows the capacitor 4 to be made smaller. Furthermore, because the capacitor 4 is made smaller, the components of the power conversion device 1 can be arranged in a space-saving manner.

[0049] <Installation example of power conversion device 1> As shown in FIG. 5, the power conversion device 1 is, for example, a device mounted on a vehicle 9. The vehicle 9 has a heat generation source 10. When the power conversion device 1 is mounted on the vehicle 9, the power conversion device 1 is thermally connected to the heat generation source 10, which is an engine, a transmission, or a motor. The cooler 2 is connected to the heat generation source 10 in the vehicle 9. In FIG. 5, the cooler 2 is the part indicated by the dashed line. When the power conversion device 1 is mounted on a vehicle and used, the amount of heat received from an external heat source also increases, so that the temperature of the power conversion device 1 is likely to rise. By using the power conversion device 1 shown in the first embodiment, heat from an external heat source can be efficiently dissipated.

[0050] As described above, in the power converter 1 according to the first embodiment, when the thermal conduction from the first electrode to the cooler is greater than the thermal conduction from the second electrode to the cooler, the cross-sectional area of ​​the second connection terminal in the direction perpendicular to the current flow is greater than the cross-sectional area of ​​the first connection terminal in the direction perpendicular to the current flow, and when the thermal conduction from the second electrode to the cooler is greater than the thermal conduction from the first electrode to the cooler, the cross-sectional area of ​​the first connection terminal in the direction perpendicular to the current flow is greater than the cross-sectional area of ​​the second connection terminal in the direction perpendicular to the current flow. Therefore, without adding any new components, the amount of heat generated by the first connection terminal of the first electrode or the second connection terminal of the second electrode, which has little thermal conduction to the cooler and is difficult to cool, is reduced, and the amount of heat transmitted to the electronic components can be reduced. Since the amount of heat transmitted to the electronic components is reduced, a power converter that suppresses temperature rise of the electronic components while maintaining a small size can be obtained.

[0051] In the case where the electronic component is a capacitor 4, the main body is one or more capacitor elements 41, the first electrode is a positive bus bar 42a, the second electrode is a negative bus bar 42b, and the capacitor 4 further includes a case 44 that houses the capacitor element 41, the positive bus bar 42a, and the negative bus bar 42b, the cross-sectional area of ​​the first connection terminal 45a of the positive bus bar 42a, which has a small amount of heat transferred to the cooler 2 and is difficult to cool, is larger than the cross-sectional area of ​​the second connection terminal 45b of the negative bus bar 42b, so that the amount of heat generated by the first connection terminal 45a is reduced, and the amount of heat transferred to the capacitor element 41 can be reduced. Since the amount of heat transferred to the capacitor element 41 is reduced, the temperature rise of the capacitor 4 can be suppressed. In addition, since the capacitor element 41, the positive bus bar 42a, and the negative bus bar 42b are housed in the case 44, the productivity of the power conversion device 1 can be improved.

[0052] When the DC power supply connecting positive bus bar 71a and the DC power supply connecting negative bus bar 71b are thermally connected to the cooler 2 via a heat transfer member, heat generated in the DC power supply connecting bus bar 71 can be dissipated to the cooler 2 while ensuring insulation between the DC power supply connecting bus bar 71 and the cooler 2, and therefore the temperature of the DC power supply connecting bus bar 71 is lower than that of the other component connecting terminal 45, and therefore the heat of the condenser bus bar 42 and the capacitor element 41 can be dissipated to the cooler 2 via the other component connecting terminal 45. Since the heat of the condenser bus bar 42 and the capacitor element 41 is dissipated to the cooler 2, deterioration of the capacitor element 41 due to heat can be suppressed.

[0053] When a Y capacitor for removing noise is electrically connected to each of the first connection terminal 45a of the positive bus bar 42a and the second connection terminal 45b of the negative bus bar 42b, the Y capacitor 46 is connected to the first connection terminal 45a, which has a large cross-sectional area and generates a small amount of heat, and therefore the temperature of the Y capacitor 46 can be effectively reduced. The second connection terminal 45b of the negative bus bar 42b transfers a large amount of heat to the cooler 2, and therefore the temperature rise of the Y capacitor 47 connected to the second connection terminal 45b can be suppressed.

[0054] When the first connection terminal 45a of the positive bus bar 42a and the second connection terminal 45b of the negative bus bar 42b have the same thickness and the first connection terminal 45a of the positive bus bar 42a and the second connection terminal 45b of the negative bus bar 42b have different widths in a direction perpendicular to the direction of current flow, the cross-sectional areas of the first connection terminal 45a and the second connection terminal 45b can be easily changed while keeping the thicknesses the same. By increasing the width of only the first connection terminal 45a and keeping the width of the second connection terminal 45b small, the capacitor 4 can be made smaller than when the widths of both the positive bus bar 42a and the negative bus bar 42b are increased.

[0055] When the heat transfer members are pedestal 74 and grease 75, which are insulating materials provided one on top of the other, the grease 75 can be made thinner by pressing pedestal 74 against cooler 2 with screws or the like, so that the contact thermal resistance between pedestal 74 and cooler 2 can be made smaller than when a heat transfer member other than grease 75 is used. Since the contact thermal resistance between pedestal 74 and cooler 2 is reduced, the heat dissipation from DC power supply connection bus bar 71 to cooler 2 can be improved.

[0056] When the Y capacitors 46, 47 are housed in the case 44 and connected to the first connection terminal 45a of the positive bus bar 42a and the second connection terminal 45b of the negative bus bar 42b inside the case 44, the Y capacitors 46, 47 and the capacitor element 41 are housed in the same case 44, which reduces dead space in the capacitor 4 and allows the capacitor 4 to be made smaller. Furthermore, because the capacitor 4 is made smaller, the components of the power conversion device 1 can be arranged in a space-saving manner.

[0057] When the first connection terminal 45a and the second connection terminal 45b are connected to the DC power supply connecting bus bar 71, which is another component, by screwing, the power conversion device 1 can be manufactured at a lower cost than when they are connected by welding. In addition, since the other component connecting terminal 45 and the DC power supply connecting bus bar 71 can be connected over a large area, the contact thermal resistance between the other component connecting terminal 45 and the DC power supply connecting bus bar 71 can be reduced. Since the contact thermal resistance between the other component connecting terminal 45 and the DC power supply connecting bus bar 71 is reduced, more heat can be dissipated from the condenser 4 to the cooler 2 via the DC power supply connecting bus bar 71.

[0058] When the first connection terminal 45a and the second connection terminal 45b are connected to the DC power supply bus bar 71, which is another component, by welding, it is possible to reduce the contact thermal resistance between the first connection terminal 45a and the second connection terminal 45b and the DC power supply bus bar 71. Since the contact thermal resistance between the first connection terminal 45a and the second connection terminal 45b and the DC power supply bus bar 71 is reduced, it is possible to improve the effect of dissipating heat from the first connection terminal 45a and the second connection terminal 45b to the DC power supply bus bar 71. Furthermore, compared to connection by screws, it is possible to connect the first connection terminal 45a and the second connection terminal 45b to the DC power supply bus bar 71 in a space-saving manner.

[0059] When capacitor element 41 is a film capacitor, film capacitors generally have a higher withstand voltage than other types of capacitors, so by using a film capacitor for capacitor element 41, the power conversion device 1 can be used for vehicle applications where high withstand voltage is required.

[0060] When the power conversion device 1 is mounted on a vehicle 9 and thermally connected to a heat generation source 10, such as an engine, a transmission, or a motor, the power conversion device 1 disclosed herein can be used to efficiently dissipate heat from an external heat source.

[0061] Embodiment 2 A power converter 1 according to a second embodiment will be described. Fig. 6 is a plan view showing an outline of the power converter 1 according to the second embodiment with the substrate 5 removed, Fig. 7 is a plan view showing an outline of the positive bus bar 42a of the power converter 1, Fig. 8 is a side view showing an outline of the positive bus bar 42a of the power converter 1, and Fig. 9 is a cross-sectional view of the power converter 1 cut at the CC cross section position in Fig. 6. The power converter 1 according to the second embodiment has a different arrangement of the opening 49 of the case 44 from that of the first embodiment.

[0062] The electronic component included in the power conversion device 1 in this embodiment is a capacitor 4. As shown in Fig. 9, the power conversion device 1 includes a semiconductor module 3 that is electrically connected to the capacitor 4 and arranged alongside the capacitor 4. A case 44 of the capacitor 4 is open on the side of the semiconductor module 3, and a first connection terminal 45a of the positive bus bar 42a and a second connection terminal 45b of the negative bus bar 42b protrude from an opening 49 that is the open portion of the case 44.

[0063] With this configuration, the first connection terminal 45a of the positive bus bar 42a and the second connection terminal 45b of the negative bus bar 42b do not protrude in the normal direction from the case 44, thereby reducing the size in the height direction of the power conversion device 1. In this embodiment, as shown in Fig. 6, the first connection terminal 45a and the second connection terminal 45b protrude from the opening 49 via the first electrode main body portion 42c1 and the second electrode main body portion 42c2, but this is not limited to this, and the first connection terminal 45a and the second connection terminal 45b may also be configured to directly protrude from the opening 49.

[0064] The positive power terminal 42a1 of the positive busbar 42a protrudes from the opening 49 toward the semiconductor module 3 and is electrically connected to the positive busbar 33a of the semiconductor module 3. Similarly, the negative power terminal 42b1 of the negative busbar 42b protrudes from the opening 49 toward the semiconductor module 3 and is electrically connected to the negative busbar 33b of the semiconductor module 3. This configuration allows the lengths of the positive power terminal 42a1 and the negative power terminal 42b1 to be shortened. Since the lengths of the positive power terminal 42a1 and the negative power terminal 42b1 are shortened, the capacitor 4 and the semiconductor module 3 can be connected with low wiring inductance, and the occurrence of excess loss in the capacitor busbar 42 connecting the capacitor 4 and the semiconductor module 3 can be suppressed. In addition, since the positive power terminal 42a1 and the negative power terminal 42b1 do not protrude from the case 44 in the normal direction, the size of the power conversion device 1 in the height direction can be reduced.

[0065] The outer surface of the side wall 44b of the case 44 and the second surface 2c of the cooler 2 are thermally connected. The thermal connection is not limited to the case where the side wall 44b and the second surface 2c are connected through direct contact, and the side wall 44b and the second surface 2c may be thermally connected via a heat transfer member such as grease or a heat dissipation sheet. By thermally connecting the case 44 to the cooler 2, the capacitor element 41 can dissipate heat from the side of the side wall 44b of the case 44, and therefore the heat dissipation performance of the capacitor element 41 can be improved.

[0066] In this embodiment, the Y capacitors 46, 47 are housed in a separate case 46a that is different from the case 44. In Fig. 6, only the outer shape of the case 46a is shown. This configuration makes it difficult for the Y capacitors 46, 47 to receive the heat generated by the capacitor element 41. In addition, since the Y capacitors 46, 47, which are smaller than the capacitor 4, have a higher degree of freedom in terms of the mounting position, the Y capacitors 46, 47 can be placed in an optimal location in consideration of heat, size, noise removal performance, and the like.

[0067] In this embodiment, the positive busbar 42a is an electrically conductive member in which a first electrode body portion 42c1 and a first connection terminal 45a, which have different cross-sectional areas, are joined together, and the negative busbar 42b is an electrically conductive member in which a second electrode body portion 42c2 and a second connection terminal 45b, which have different cross-sectional areas, are joined together. As shown in FIG. 8, the positive busbar 42a is joined by a screw 72 to the first electrode body portion 42c1 and the first connection terminal 45a, which have different cross-sectional areas. The negative busbar 42b has a similar configuration. FIG. 8 is a view of the positive busbar 42a shown in FIG. 7 as viewed in the second direction. The joining is not limited to screwing, and may be welding. With this configuration, the degree of freedom of the path of the capacitor busbar 42 is increased, and the power converter 1 can be made smaller. Note that the first electrode body portion 42c1 and the positive power terminal 42a1 cut out from a single copper plate are integrated, but this is not limited thereto. The first electrode main portion 42c1 and the positive power terminal 42a1 may be formed from separate members.

[0068] In this embodiment, the heat transfer member is a heat dissipation sheet 76. As shown in FIG. 6, the bus bar 71 for connecting a DC power source is thermally connected to the cooler 2 via the heat dissipation sheet 76. Since the heat dissipation sheet 76 has a stable shape, even if the heat dissipation sheet 76 is used for a long period of time and high and low temperatures are repeatedly applied to the heat dissipation sheet 76, the heat dissipation sheet 76 can maintain the desired heat dissipation characteristics. In addition, by using the heat dissipation sheet 76 having insulating properties, it is not necessary to install a separate insulating member between the bus bar 71 for connecting a DC power source and the cooler 2, and the distance between the bus bar 71 for connecting a DC power source and the cooler 2 is reduced, so that the heat dissipation property of the bus bar 71 for connecting a DC power source can be further improved. By improving the heat dissipation property of the bus bar 71 for connecting a DC power source, the heat of the capacitor bus bar 42 and the capacitor element 41 is further dissipated to the cooler 2, so that the deterioration caused by the heat of the capacitor element 41 can be further suppressed.

[0069] Embodiment 3 The power conversion device 1 according to the third embodiment will be described. Fig. 10 is a plan view showing an outline of the power conversion device 1 according to the third embodiment, Fig. 11 is a cross-sectional view of a semiconductor module 3 of the power conversion device 1 taken along the DD cross section of Fig. 10, and Fig. 12 is a cross-sectional view of a semiconductor module bus bar 33 which is a main part of the power conversion device 1 taken along the EE cross section of Fig. 10. In the power conversion device 1 according to the third embodiment, the electronic component possessed by the power conversion device 1 is the semiconductor module 3.

[0070] The power conversion device 1 includes a capacitor 4 in addition to the semiconductor module 3. Although the description of the configuration of the capacitor 4 is omitted in this embodiment, the capacitor 4 may have the configuration shown in the first or second embodiment. The semiconductor module 3 and the capacitor 4 are thermally connected to the cooler 2 as shown in FIG. 10. As shown in FIG. 11, the semiconductor module 3 is composed of a semiconductor element 31, a positive bus bar 33a (not shown in FIG. 11), a negative bus bar 33b, a heat spreader 32 for heat dissipation, an insulating member 36, and a sealing resin 35 that integrally seals these. The semiconductor module 3 is thermally connected to the cooler 2 via the insulating member 36. A bonding material 34 such as solder or grease is provided between the insulating member 36 and the cooler 2. In this embodiment, an example in which the semiconductor element 31 is singular has been shown, but the number of semiconductor elements 31 is not limited to singular and may be plural.

[0071] The semiconductor element 31 has electrodes on one surface and the other surface. When the semiconductor element 31 is a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), the electrodes are a drain and a source. When the semiconductor element 31 is an IGBT (Insulated Gate Bipolar Transistor), the electrodes are a collector and an emitter. An electrode 31a on one surface of the semiconductor element 31 is connected to the heat spreader 32 via a bonding material 34a such as solder. An electrode 31b on the other surface of the semiconductor element 31 is connected to a negative bus bar 33b via a bonding material 34a such as solder. As shown in FIG. 12, the positive bus bar 33a is connected to the same surface of the heat spreader 32 on which the semiconductor element 31 is provided, via a bonding material 34a. An insulating member 36 is arranged on the surface of the heat spreader 32 opposite to the surface on which the semiconductor element 31 is provided. The positive bus bar 33a and the negative bus bar 33b extend parallel to the surface of the cooler 2 on which the semiconductor modules 3 are provided, and protrude from the sealing resin .

[0072] The main body of the electronic component is one or more semiconductor elements 31, the first electrode is negative bus bar 33b, and the second electrode is heat spreader 32 and positive bus bar 33a. The portion of negative bus bar 33b connected to semiconductor element 31 is a first electrode main body, and the portion of negative bus bar 33b protruding from sealing resin 35 and connected to capacitor 4, which is another component, is a first connection terminal. Heat spreader 32 is a second electrode main body, and positive bus bar 33a is a second connection terminal. In this embodiment, as shown in FIG. 12, the cross-sectional area of ​​negative bus bar 33b is larger than the cross-sectional area of ​​positive bus bar 33a.

[0073] Since the path to the cooler 2 is via the semiconductor element 31, which is a heat source, the negative bus bar 33b transfers less heat to the cooler 2 than the positive bus bar 33a, which is directly connected to the heat spreader 32. When a large current flows through the semiconductor element 31, not only the semiconductor element 31 generates heat itself, but also the heat received from the semiconductor module bus bar 33 increases, so that the temperature of the semiconductor element 31 may exceed the allowable value. Since the heat of the negative bus bar 33b is directly connected to the semiconductor element 31, it has a large effect on the temperature of the semiconductor element 31. Therefore, the temperature of the semiconductor element 31 can be lowered by increasing the cross-sectional area of ​​the negative bus bar 33b in the direction perpendicular to the current path 8, which is the direction in which the current flows, and reducing the amount of heat generated by the negative bus bar 33b.

[0074] Furthermore, when the temperature of other components connected to the semiconductor module bus bar 33 is low, the heat of the semiconductor module 3 can be dissipated to the other components. In this embodiment, the first connection terminal and the second connection terminal of the semiconductor module 3 are connected to the capacitor bus bar (not shown) of the capacitor 4 by welding, so that part of the heat of the semiconductor element 31 is dissipated to the capacitor 4 side.

[0075] In the present embodiment, the capacitor 4 is electrically connected to the semiconductor module 3 via a first connection terminal and a second connection terminal of the semiconductor module 3. The first connection terminal is a portion of the negative bus bar 33b that protrudes from the sealing resin 35 and is connected to the capacitor 4, and the second connection terminal is the positive bus bar 33a. The cooler 2 has a forced cooling section 21 provided with a flow path 22 through which a refrigerant flows, and the semiconductor module 3 is thermally connected to the forced cooling section 21.

[0076] With this configuration, when the temperature of the capacitor 4 to which the semiconductor module 3 is connected is high, the heat of the condenser bus bar of the capacitor 4 can be efficiently dissipated to the flow path 22.

[0077] Embodiment 4 A power conversion device 1 according to a fourth embodiment will be described. Fig. 13 is a cross-sectional view showing an outline of the power conversion device 1 according to the fourth embodiment, in which the power conversion device 1 is cut at the same position as in Fig. 2, Fig. 14 is a side view showing an outline of a rapid discharge resistor 6 of the power conversion device 1, and Fig. 15 is a cross-sectional view of a main part of the rapid discharge resistor 6 cut at the FF cross section position in Fig. 14. In the power conversion device 1 according to the fourth embodiment, the electronic component included in the power conversion device 1 is the rapid discharge resistor 6 that releases the charge stored in the capacitor 4.

[0078] The power conversion device 1 includes a semiconductor module 3 in addition to the capacitor 4 and the rapid discharge resistor 6. Although the description of the configurations of the semiconductor module 3 and the capacitor 4 is omitted in this embodiment, the semiconductor module 3 and the capacitor 4 may have the configurations shown in the first to third embodiments. The rapid discharge resistor 6 is provided to discharge the charge accumulated in the capacitor 4 when an abnormality is detected in the power conversion device 1. As shown in FIG. 14, the rapid discharge resistor 6 has a resistor 62 that discharges the charge of the capacitor 4, a lead wire 61 that electrically connects the resistor 62 and the capacitor 4, and a case 63 that accommodates the resistor 62. In this embodiment, a first lead wire 61a and a second lead wire 61b are provided as the lead wire 61, the first lead wire 61a is connected to the first connection terminal 45a, and the second lead wire 61b is connected to the second connection terminal 45b (not shown in FIG. 13). The case 63 is thermally connected to the cooler 2 as shown in FIG. 13. In the present embodiment, an example in which there is a single resistor 62 has been shown, but the number of resistors 62 is not limited to one, and there may be a plurality of resistors 62 .

[0079] 14, the resistor 62 has electrodes on one surface and the other surface. The electrode 62a on one surface of the resistor 62 is connected to a first lead wire 61a via a bonding material such as solder (not shown). The electrode 62b on the other surface of the semiconductor element 31 is connected to a second lead wire 61b via a bonding material such as solder (not shown). The first lead wire 61a and the second lead wire 61b protrude from the case 63 to the other side in the first direction.

[0080] The main body of the electronic component is one or more resistors 62, the first electrode is the second lead wire 61b, and the second electrode is the first lead wire 61a. The part of the second lead wire 61b connected to the resistor 62 is the first electrode main body, and the part of the second lead wire 61b protruding from the case 63 and connected to the capacitor 4, which is another component, is the first connection terminal. The part of the first lead wire 61a connected to the resistor 62 is the second electrode main body, and the part of the first lead wire 61a protruding from the case 63 and connected to the capacitor 4, which is another component, is the second connection terminal. In this embodiment, as shown in FIG. 15, the cross-sectional area of ​​the second lead wire 61b is larger than the cross-sectional area of ​​the first lead wire 61a.

[0081] Since the capacitor 4 mounted on the on-vehicle power conversion device 1 has a large capacity, the rapid discharge resistor 6 generates a large amount of heat during discharge. The heat generated by the rapid discharge resistor 6 may exceed its own heat resistance temperature and may cause thermal damage to components disposed around the rapid discharge resistor 6. Therefore, by making the cross-sectional area of ​​the second lead wire 61b, which has a smaller amount of heat dissipation to the cooler 2, larger than that of the first lead wire 61a, the heat of the rapid discharge resistor 6 can be dissipated to the outside via the lead wire. In addition, by making the cross-sectional area of ​​the second lead wire 61b larger, the heat of the rapid discharge resistor 6 can be further dissipated from the surface of the second lead wire 61b to the air, thereby lowering the temperature of the rapid discharge resistor 6. In this embodiment, the cooler 2 closer to the forced cooling section 21 having the flow path 22 is at a lower temperature and a greater amount of heat is transferred from the rapid discharge resistor 6 to the cooler 2. Therefore, by increasing the cross-sectional area of ​​the second lead wire 61b on the side farther from the forced cooling section 21, the heat from the rapid discharge resistor 6 is dissipated via the lead wire.

[0082] Embodiment 5. The power converter 1 according to the fifth embodiment will be described. Fig. 16 is a cross-sectional view showing an outline of the substrate 5 of the power converter 1 according to the fifth embodiment, and Fig. 17 is a cross-sectional view of the substrate 5 of the power converter 1 taken along the cross section GG in Fig. 16. In the power converter 1 according to the fifth embodiment, the electronic component of the power converter 1 is a heat-generating component 51 provided on the substrate 5. The first connection terminal and the second connection terminal are patterns 52 provided on the substrate 5.

[0083] The power converter 1 includes, for example, a semiconductor module 3, a capacitor 4, and a rapid discharge resistor 6 in addition to the substrate 5 on which the heat generating component 51 is mounted. Although the description of the configurations of the semiconductor module 3, the capacitor 4, and the rapid discharge resistor 6 is omitted in this embodiment, the configurations of the semiconductor module 3, the capacitor 4, and the rapid discharge resistor 6 may be the configurations shown in the first to fourth embodiments. The substrate 5 is a control substrate on which electronic components used for controlling the power converter 1 are mounted. As shown in FIG. 16, the substrate 5 includes a main body portion of the substrate 5 in which an insulating layer 53 and a pattern 52 serving as a current path and a heat dissipation path are laminated, and at least one heat generating component 51 is arranged on one surface of the substrate 5. As shown in FIG. 17, the pattern 52 includes a first pattern 52a and a second pattern 52b having different cross-sectional areas. In this embodiment, the cross-sectional area of ​​the first pattern 52a is larger than the cross-sectional area of ​​the second pattern 52b. The pattern 52 is thermally connected to the cooler 2 via a cooler connection portion 55. In this embodiment, the substrate 5 has two heat generating components 51, but the number of heat generating components 51 is not limited to this.

[0084] The heat generating component 51 is, for example, a microcomputer for controlling the power conversion device 1, a semiconductor module, or a resistor. In this embodiment, the heat generating component 51 is a semiconductor module, but the heat generating component 51 is not limited to a semiconductor module. The semiconductor module is composed of a semiconductor element 56, a first lead wire 52a1, a second lead wire 52b1, a heat spreader 57 for heat dissipation, an insulating member 58, and a sealing resin 59 that integrally seals these. The semiconductor module is thermally connected to the first pattern 52a via the insulating member 58. Solder 54, which is a bonding material, is provided between the insulating member 36 and the first pattern 52a.

[0085] The semiconductor element 56 has electrodes on one surface and the other surface. When the semiconductor element 56 is a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), the electrodes are a drain and a source. When the semiconductor element 31 is an IGBT (Insulated Gate Bipolar Transistor), the electrodes are a collector and an emitter. An electrode 56b on the other surface of the semiconductor element 56 is connected to the heat spreader 57 via a bonding material (not shown) such as solder. An electrode 56a on one surface of the semiconductor element 56 is connected to a first lead wire 52a1 via a bonding material (not shown) such as solder. A second lead wire 52b1 is connected to the same surface of the heat spreader 57 on which the semiconductor element 56 is provided, via a bonding material (not shown). An insulating member 58 is disposed on the surface of the heat spreader 57 opposite to the surface on which the semiconductor element 56 is provided. The first lead wire 52a1 and the second lead wire 52b1 extend parallel to the surface of the cooler 2 on which the substrate 5 is provided, and protrude from the sealing resin 59.

[0086] The main body of the electronic component is the semiconductor element 56, the first electrode is the first lead wire 52a1 and the first pattern 52a, and the second electrode is the heat spreader 57, the second lead wire 52b1, and the second pattern 52b. The part of the first lead wire 52a1 connected to the semiconductor element 56 is the first electrode main body, and the first pattern 52a to which the first lead wire 52a1 is connected is the first connection terminal. The heat spreader 57 is the second electrode main body, and the second pattern 52b is the second connection terminal. The first pattern 52a and the second pattern 52b are connected to, for example, a capacitor that is another component. The second lead wire 52b1 and the first pattern 52a are not electrically connected.

[0087] The heat-generating component 51 is thermally connected to a pattern 52 on the substrate 5 via solder 54 or the like, and the pattern 52 is thermally connected to the cooler 2. Since the distance from the cooler 2 is greater than that of the second pattern 52b, the cross-sectional area of ​​the first pattern 52a on the side with a smaller amount of heat dissipation to the cooler 2 is made larger than that of the second pattern 52b, so that a larger amount of heat from the heat-generating component 51 can be dissipated to the cooler 2. In addition, since the heat from the heat-generating component 51 can be dissipated over a larger area via the first pattern 52a, the amount of heat dissipated from the substrate 5 to the air also increases, so that the temperatures of the heat-generating component 51 and the substrate 5 itself can be lowered.

[0088] Although the present disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to application to a particular embodiment, but may be applied to the embodiments alone or in various combinations. Therefore, countless modifications not exemplified are assumed within the scope of the technology disclosed in this specification, including, for example, modifying, adding, or omitting at least one component, and further, extracting at least one component and combining it with a component of another embodiment.

[0089] Various aspects of the present disclosure are summarized below as appendices. (Appendix 1) an electronic component including a main body which is a heating element, a first electrode electrically connected to one side of the main body, and a second electrode electrically connected to the other side opposite to the one side of the main body, the first electrode, the main body, and the second electrode being stacked in this order; a cooler for cooling the electronic component; the first electrode includes a first electrode body portion connected to the body portion, and a first connection terminal connected to the first electrode body portion and connected to another component on an opposite side to the first electrode body portion; the second electrode has a second electrode body portion connected to the body portion, and a second connection terminal connected to the second electrode body portion and connected to another component on an opposite side to the second electrode body portion; when the thermal conduction from the first electrode to the cooler is greater than the thermal conduction from the second electrode to the cooler, a cross-sectional area of ​​the second connection terminal in a direction perpendicular to a current flow direction is greater than a cross-sectional area of ​​the first connection terminal in a direction perpendicular to a current flow direction; A power conversion device in which, when thermal conduction from the second electrode to the cooler is greater than thermal conduction from the first electrode to the cooler, a cross-sectional area of ​​the first connection terminal in a direction perpendicular to the direction of current flow is greater than a cross-sectional area of ​​the second connection terminal in a direction perpendicular to the direction of current flow. (Appendix 2) the electronic component is a capacitor, the body portion is one or more capacitor elements, the first electrode is a positive bus bar, and the second electrode is a negative bus bar; 2. The power conversion device according to claim 1, wherein the capacitor further includes a case that houses the capacitor element, the positive bus bar, and the negative bus bar. (Appendix 3) a positive bus bar for connecting a DC power source, one end of which is electrically connected to a DC power source and the other end of which is electrically connected to the first connection terminal of the positive bus bar; and a negative bus bar for connecting a DC power source, one end of which is electrically connected to the DC power source and the other end of which is electrically connected to the second connection terminal of the negative bus bar, 3. The power conversion device according to claim 2, wherein the positive bus bar for connecting a DC power source and the negative bus bar for connecting a DC power source are thermally connected to the cooler via a heat transfer member. (Appendix 4) a semiconductor module electrically connected to the capacitor and arranged side by side with the capacitor; the case of the capacitor is open at a portion facing the semiconductor module, 4. The power conversion device according to claim 2, wherein the first connection terminal of the positive bus bar and the second connection terminal of the negative bus bar protrude from an open portion of the case. (Appendix 5) 5. The power conversion device according to claim 2, wherein a Y capacitor for removing noise is electrically connected to each of the first connection terminal of the positive bus bar and the second connection terminal of the negative bus bar. (Appendix 6) The power conversion device according to any one of Appendices 2 to 5, wherein the first connection terminal of the positive bus bar and the second connection terminal of the negative bus bar have an equal thickness, and the first connection terminal of the positive bus bar and the second connection terminal of the negative bus bar have different widths in a direction perpendicular to a direction in which a current flows. (Appendix 7) the positive bus bar is an electrically conductive member having a different cross-sectional area and joining the first electrode main body portion and the first connection terminal, The power conversion device according to any one of claims 2 to 6, wherein the negative bus bar is an electrically conductive member that joins the second electrode main body portion and the second connection terminal and has different cross-sectional areas. (Appendix 8) 4. The power conversion device according to claim 3, wherein the heat transfer member is an insulating material and grease provided in layers. (Appendix 9) 4. The power conversion device according to claim 3, wherein the heat transfer member is a heat dissipation sheet. (Appendix 10) the Y capacitor is housed in the case, 6. The power conversion device according to claim 5, wherein the Y capacitor is connected to each of the first connection terminal of the positive bus bar and the second connection terminal of the negative bus bar inside the case. (Appendix 11) 6. The power conversion device according to claim 5, wherein the Y capacitor is housed in a separate case different from the case. (Appendix 12) the electronic component is a semiconductor module, the body portion is one or more semiconductor elements, 2. The power conversion device according to claim 1, wherein the semiconductor module is thermally connected to the cooler via an insulating member. (Appendix 13) Further comprising a capacitor; the electronic component is a rapid discharge resistor that discharges electric charge stored in the capacitor; The power conversion device according to claim 1, wherein the main body portion is a single or multiple resistors. (Appendix 14) Further comprising a substrate; the electronic component is a heat-generating component provided on the substrate, The power conversion device according to claim 1, wherein the first connection terminal and the second connection terminal are patterns provided on the substrate. (Appendix 15) Further comprising a capacitor; the capacitor is electrically connected to the semiconductor module via the first connection terminal and the second connection terminal of the semiconductor module; The cooler has a forced cooling section provided with a flow path through which a refrigerant flows, 13. The power conversion device according to claim 12, wherein the semiconductor module is thermally connected to the forced cooling unit. (Appendix 16) 16. The power conversion device according to any one of claims 1 to 15, wherein the first connection terminal, the second connection terminal, and the other component are connected by screw fastening. (Appendix 17) 16. The power converter according to any one of claims 1 to 15, wherein the first connection terminal and the second connection terminal are connected to the other component by welding. (Appendix 18) 12. The power conversion device according to claim 2, wherein the capacitor element is a film capacitor. (Appendix 19) 19. The power conversion device according to any one of appendix 1 to 18, which is mounted on a vehicle and thermally connected to a heat generating source, such as an engine, a transmission, or a motor. [Explanation of symbols]

[0090] 1 power conversion device, 2 cooler, 2a step, 2b first surface, 2c second surface, 21 forced cooling section, 22 flow path, 23 flow path forming section, 24a, 24b refrigerant inlet / outlet, 3 semiconductor module, 3a module main body, 31 semiconductor element, 31a, 31b electrode, 32 heat spreader, 33 semiconductor module bus bar, 33a positive bus bar, 33b negative bus bar, 34, 34a bonding material, 35 sealing resin, 36 insulating member, 38 output terminal, 4 capacitor, 41 capacitor element, 42 capacitor bus bar, 42a positive bus bar, 42a1 positive power terminal, 42a2 board connection terminal, 42b negative bus bar, 42b1 negative power terminal, 42c1 first electrode main body, 42c2 second electrode main body, 43 sealing resin, 44 Case, 44a bottom wall, 44b side wall, 45 terminal for connecting other components, 45a first connecting terminal, 45b second connecting terminal, 46, 47 Y capacitor, 46a case, 48 electrode, 48a positive electrode, 48b negative electrode, 49 opening, 5 board, 51 heat generating component, 52 pattern, 52a first pattern, 52a1 first lead wire, 52b second pattern, 52b1 second lead wire, 53 insulating layer, 54 solder, 55 cooler connection portion, 56 semiconductor element, 56a, 56b electrodes, 57 heat spreader, 58 insulating member, 59 sealing resin, 6 rapid discharge resistor, 61 lead wire, 61a first lead wire, 61b second lead wire, 62 resistor, 62a, 62b electrodes, 63 case, 7 DC power supply, 71 DC power supply connection bus bar, 71a DC power supply connection positive bus bar, 71b DC power supply connection negative bus bar, 72 screw, 73 welded part, 74 base, 75 grease, 76 heat dissipation sheet, 8 current path, 9 vehicle, 10 heat generation source

Claims

1. an electronic component including a main body which is a heating element, a first electrode electrically connected to one side of the main body, and a second electrode electrically connected to the other side opposite to the one side of the main body, the first electrode, the main body, and the second electrode being stacked in this order; a cooler for cooling the electronic component; the first electrode includes a first electrode body portion connected to the body portion, and a first connection terminal connected to the first electrode body portion and connected to another component on an opposite side to the first electrode body portion; the second electrode has a second electrode body portion connected to the body portion, and a second connection terminal connected to the second electrode body portion and connected to another component on an opposite side to the second electrode body portion; when the thermal conduction from the first electrode to the cooler is greater than the thermal conduction from the second electrode to the cooler, a cross-sectional area of ​​the second connection terminal in a direction perpendicular to a current flow direction is greater than a cross-sectional area of ​​the first connection terminal in a direction perpendicular to a current flow direction; A power conversion device in which, when thermal conduction from the second electrode to the cooler is greater than thermal conduction from the first electrode to the cooler, a cross-sectional area of ​​the first connection terminal in a direction perpendicular to the direction of current flow is greater than a cross-sectional area of ​​the second connection terminal in a direction perpendicular to the direction of current flow.

2. the electronic component is a capacitor, the body portion is one or more capacitor elements, the first electrode is a positive bus bar, and the second electrode is a negative bus bar; The power conversion device according to claim 1 , wherein the capacitor further includes a case that houses the capacitor element, the positive bus bar, and the negative bus bar.

3. a positive bus bar for connecting a DC power source, one end of which is electrically connected to a DC power source and the other end of which is electrically connected to the first connection terminal of the positive bus bar; and a negative bus bar for connecting a DC power source, one end of which is electrically connected to the DC power source and the other end of which is electrically connected to the second connection terminal of the negative bus bar, The power conversion device according to claim 2 , wherein the positive bus bar for connecting a DC power source and the negative bus bar for connecting a DC power source are thermally connected to the cooler via a heat transfer member.

4. a semiconductor module electrically connected to the capacitor and arranged side by side with the capacitor; the case of the capacitor is open at a portion facing the semiconductor module, The power conversion device according to claim 2 , wherein the first connection terminal of the positive bus bar and the second connection terminal of the negative bus bar protrude from an open portion of the case.

5. 3. The power conversion device according to claim 2, wherein a Y capacitor for removing noise is electrically connected to each of the first connection terminal of the positive bus bar and the second connection terminal of the negative bus bar.

6. 3. The power conversion device according to claim 2, wherein the first connection terminal of the positive bus bar and the second connection terminal of the negative bus bar have an equal thickness, and the first connection terminal of the positive bus bar and the second connection terminal of the negative bus bar have different widths in a direction perpendicular to a direction in which a current flows.

7. the positive bus bar is an electrically conductive member having a different cross-sectional area and joining the first electrode main body portion and the first connection terminal, The power conversion device according to claim 2 , wherein the negative bus bar is an electrically conductive member that joins the second electrode main body portion and the second connection terminal, the cross-sectional areas of which are different from each other.

8. The power converter according to claim 3 , wherein the heat transfer member is an insulating material and grease provided in a layered manner.

9. The power conversion device according to claim 3 , wherein the heat transfer member is a heat dissipation sheet.

10. The Y capacitor is housed in the case, The power conversion device according to claim 5 , wherein the Y capacitor is connected to each of the first connection terminal of the positive bus bar and the second connection terminal of the negative bus bar inside the case.

11. The power conversion device according to claim 5 , wherein the Y capacitor is accommodated in a separate case that is different from the case.

12. the electronic component is a semiconductor module, the body portion is one or more semiconductor elements, The power conversion device according to claim 1 , wherein the semiconductor module is thermally connected to the cooler via an insulating member.

13. Further comprising a capacitor; the electronic component is a rapid discharge resistor that discharges electric charge stored in the capacitor; The power conversion device according to claim 1 , wherein the main body portion is one or more resistors.

14. Further comprising a substrate; the electronic component is a heat-generating component provided on the substrate, The power conversion device according to claim 1 , wherein the first connection terminal and the second connection terminal are patterns provided on the substrate.

15. Further comprising a capacitor; the capacitor is electrically connected to the semiconductor module via the first connection terminal and the second connection terminal of the semiconductor module; The cooler has a forced cooling section provided with a flow path through which a refrigerant flows, The power conversion device according to claim 12 , wherein the semiconductor module is thermally connected to the forced cooling unit.

16. The power conversion device according to claim 1 , wherein the first connection terminal and the second connection terminal are connected to the other component by screwing.

17. The power conversion device according to claim 1 , wherein the first connection terminal and the second connection terminal are connected to the other component by welding.

18. The power conversion device according to claim 2 , wherein the capacitor element is a film capacitor.

19. The power conversion device according to any one of claims 1 to 18, which is mounted on a vehicle and thermally connected to a heat generating source, that is, an engine, a transmission, or a motor.

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