Capacitor module

Abstract

To provide a capacitor module that can improve heat dissipation while simplifying the configuration.SOLUTION: A capacitor module 23 includes a plurality of capacitor elements 30 arranged in the X direction, a capacitor case 40, a plurality of capacitor bus bars 50, and a sealing resin body 60. From among the plurality of capacitor bus bars 50, the N bus bar 54 has an intervening portion 54N that is interposed between the side surfaces 303 of adjacent capacitor elements 30. At any position in the Z direction, only one intervening portion 54N is disposed between the side surfaces 303, or one intervening portion 54N and a portion of the sealing resin body 60 that is thinner than the intervening portion 54N are disposed between the side surfaces 303.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The disclosure herein relates to a capacitor module. [Background technology]

[0002] Patent Document 1 discloses a cooling structure for a condenser. The contents of the prior art document are incorporated by reference as an explanation of the technical elements in this specification. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-178839 Summary of the Invention [Problem to be solved by the invention]

[0004] As exemplified in Patent Document 1, multiple capacitor elements arranged in a predetermined direction are typically housed in a capacitor case and sealed with a sealing resin such as a potting material. When multiple capacitor elements are sealed with a sealing resin and arranged side by side, heat tends to build up inside the capacitor elements. It is particularly difficult to dissipate heat from the center of the capacitor elements. In Patent Document 1, a cooling plate is placed between adjacent capacitor elements. This increases the number of components, making the configuration more complex. Further improvements are needed in capacitor modules from the above and other unmentioned perspectives.

[0005] One object of the present disclosure is to provide a capacitor module that can improve heat dissipation while simplifying the configuration. [Means for solving the problem]

[0006] A capacitor module according to one embodiment of the present disclosure includes: A plurality of capacitor elements (30) arranged in a predetermined direction; a capacitor case (40) that houses a plurality of capacitor elements; a plurality of capacitor bus bars (50) electrically connected to the capacitor elements; a sealing resin body (60) disposed within the capacitor case and sealing the capacitor element and a portion of each of the plurality of capacitor bus bars; Equipped with At least one of the plurality of capacitor bus bars has an interposition portion (54N, 54P) interposed between opposing surfaces of adjacent capacitor elements, At any position in one direction perpendicular to the predetermined direction, only one intervening portion, or one intervening portion and a portion of the sealing resin body that is thinner than the intervening portion, are arranged between the opposing surfaces.

[0007] According to the disclosed capacitor module, an intervening portion of the capacitor bus bar is disposed between the opposing surfaces of adjacent capacitor elements. This allows heat generated by the capacitor elements to be dissipated through the capacitor bus bar. At any position in one direction perpendicular to the predetermined direction, only one intervening portion, or one intervening portion and a sealing resin body, is present between the opposing surfaces. In other words, at any position, only one capacitor bus bar, or one capacitor bus bar and a sealing resin body, is disposed. This allows for improved heat dissipation while simplifying the configuration.

[0008] The various aspects disclosed in this specification employ different technical means to achieve their respective objectives. The reference numerals in parentheses in the claims are intended to exemplarily indicate the corresponding parts of the embodiments described below, and are not intended to limit the technical scope. The objectives, features, and advantages disclosed in this specification will become more apparent by reference to the following detailed description and the accompanying drawings. [Brief explanation of the drawings]

[0009] [Figure 1]1 is a diagram showing a power conversion circuit and a drive system to which a capacitor module according to a first embodiment is applied. [Figure 2] FIG. 2 is a plan view showing the power conversion device. [Figure 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. [Figure 4] FIG. 2 is a cross-sectional view showing a capacitor module. [Figure 5] FIG. 10 is a cross-sectional view showing a modified example. [Figure 6] FIG. 10 is a cross-sectional view showing a modified example. [Figure 7] FIG. 4 is a cross-sectional view showing a capacitor module according to a second embodiment. [Figure 8] 10 is a plan view showing the structure of a bus bar having an interposition portion in a capacitor module according to a third embodiment. FIG. [Figure 9] FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. 8. [Figure 10] FIG. 10 is a cross-sectional view showing a modified example. [Figure 11] FIG. 10 is a cross-sectional view showing a capacitor module according to a fourth embodiment. [Figure 12] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, several embodiments will be described with reference to the drawings. Note that in each embodiment, corresponding components are designated by the same reference numerals, and redundant description may be omitted. When only a portion of the configuration is described in each embodiment, the configuration of another embodiment previously described may be applied to the remaining portion of the configuration. Furthermore, in addition to the combinations of configurations explicitly stated in the description of each embodiment, configurations of several embodiments may be partially combined together even if not explicitly stated, provided that there is no particular problem with the combination.

[0011] (First embodiment) The capacitor module of this embodiment is applied to, for example, a mobile body that uses a rotating electric machine as a drive source. Examples of the mobile body include electric vehicles such as battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs), electric flying bodies such as drones and electric vertical take-off and landing aircraft (eVTOLs), ships, construction machinery, and agricultural machinery. BEV is an abbreviation for Battery Electric Vehicle. HEV is an abbreviation for Hybrid Electric Vehicle. eVTOL is an abbreviation for electronic Vertical Take-Off and Landing aircraft. An example of application to a vehicle will be described below.

[0012] <Vehicle drive system> As shown in FIG. 1, a vehicle drive system 1 includes a DC power supply 2, a motor generator 3, and a power conversion circuit 4.

[0013] The DC power supply 2 is a DC voltage source made up of a rechargeable secondary battery. The secondary battery may be, for example, a lithium-ion battery or a nickel-metal hydride battery. The motor generator 3 is a three-phase AC rotating electric machine. The motor generator 3 functions as a drive source for the vehicle, that is, an electric motor. The motor generator 3 functions as a generator during regeneration. The power conversion circuit 4 converts power between the DC power supply 2 and the motor generator 3.

[0014] <Power conversion circuit> 1 shows an example of a power conversion circuit 4. The power conversion circuit 4 shown in FIG.

[0015] The smoothing capacitor 5 mainly smoothes the DC voltage supplied from the DC power supply 2. The smoothing capacitor 5 is connected to a P line 7, which is a power supply line on the high potential side, and an N line 8, which is a power supply line on the low potential side. The P line 7 is connected to the positive electrode of the DC power supply 2, and the N line 8 is connected to the negative electrode of the DC power supply 2. The positive electrode of the smoothing capacitor 5 is connected to the P line 7 between the DC power supply 2 and the inverter 6. The negative electrode of the smoothing capacitor 5 is connected to the N line 8 between the DC power supply 2 and the inverter 6. The smoothing capacitor 5 is connected in parallel to the DC power supply 2.

[0016] The inverter 6 is a DC-AC conversion circuit. In accordance with switching control by the control circuit, the inverter 6 converts a DC voltage into a three-phase AC voltage and outputs it to the motor generator 3. This drives the motor generator 3 to generate a predetermined torque. During regenerative braking of the vehicle, the inverter 6 converts the three-phase AC voltage generated by the motor generator 3 in response to rotational force from the wheels into a DC voltage in accordance with switching control by the control circuit and outputs it to the P line 7. In this way, the inverter 6 performs bidirectional power conversion between the DC power supply 2 and the motor generator 3.

[0017] The inverter 6 is configured to include upper and lower arm circuits 9 for three phases. The upper and lower arm circuits 9 are sometimes referred to as legs. Each upper and lower arm circuit 9 has an upper arm 9H and a lower arm 9L. The upper arm 9H and the lower arm 9L are connected in series between the P line 7 and the N line 8, with the upper arm 9H on the P line 7 side. Hereinafter, the upper arm 9H and the lower arm 9L may be simply referred to as arms 9H and 9L.

[0018] The connection point between the upper arm 9H and the lower arm 9L, i.e., the midpoint of the upper and lower arm circuits 9, is connected to the corresponding phase winding 3a of the motor generator 3 via an output line 10. Of the upper and lower arm circuits 9, the U-phase upper and lower arm circuit 9U is connected to the U-phase winding 3a via the output line 10. The V-phase upper and lower arm circuit 9V is connected to the V-phase winding 3a via the output line 10. The W-phase upper and lower arm circuit 9W is connected to the W-phase winding 3a via the output line 10.

[0019] The number of switching elements constituting each arm 9H, 9L is not particularly limited. It may be one or more. In the illustrated upper arm 9H, two switching elements are connected in parallel. In the lower arm 9L, two switching elements are connected in parallel. In other words, each of the six arms 9H, 9L of the three-phase upper and lower arm circuit 9 is composed of two switching elements connected in parallel to each other.

[0020] The illustrated switching element is an n-channel MOSFET 11. MOSFET is an abbreviation for Metal Oxide Semiconductor Field Effect Transistor. The two high-side MOSFETs 11 connected in parallel are turned on and off at the same timing by a common gate drive signal (drive voltage). The two low-side MOSFETs 11 connected in parallel are turned on and off at the same timing by a common gate drive signal (drive voltage).

[0021] A freewheeling diode 12 is connected in anti-parallel to each MOSFET 11. The diode 12 may be a parasitic diode (body diode) or an external diode. In the upper arm 9H, the drain of the MOSFET 11 is connected to the P line 7. In the lower arm 9L, the source of the MOSFET 11 is connected to the N line 8. The source of the MOSFET 11 in the upper arm 9H and the drain of the MOSFET 11 in the lower arm 9L are connected to each other. The anode of the diode 12 is connected to the source of the corresponding MOSFET 11, and the cathode is connected to the drain.

[0022] The switching element is not limited to the MOSFET 11. For example, an IGBT may be used. IGBT is an abbreviation for Insulated Gate Bipolar Transistor. In the case of an IGBT, a freewheeling diode is also connected in anti-parallel.

[0023] The power conversion circuit 4 may include a converter. The converter is a DC-DC conversion circuit configured to be able to convert a DC voltage into a DC voltage of a different value, for example. The converter is provided between the DC power supply 2 and the smoothing capacitor 5. The converter is configured to include, for example, a reactor and the above-mentioned upper and lower arm circuits 9. This configuration allows for voltage step-up and step-down. The power conversion circuit 4 may also include a filter capacitor. The filter capacitor is provided between the DC power supply 2 and the converter.

[0024] The power conversion circuit 4 may include a snubber circuit. The snubber circuit is connected in parallel to the upper and lower arm circuits 9. The snubber circuit reduces the inductance of the upper and lower arm circuits 9. In other words, the snubber circuit absorbs a transient high voltage, a so-called switching surge, that occurs when the switching elements (MOSFETs 11) that constitute the upper and lower arm circuits 9 are switched. This enables the inverter 6 to perform high-speed switching.

[0025] The power conversion circuit 4 may include a drive circuit for a switching element constituting the inverter 6 or the like. The drive circuit supplies a drive voltage to the gate of the MOSFET 11 of the corresponding arm based on a drive command from the control circuit. The drive circuit drives the corresponding MOSFET 11, i.e., turns it on and off, by applying the drive voltage. The drive circuit is sometimes referred to as a driver.

[0026] The power conversion circuit 4 may include a control circuit for the switching element. The control circuit generates a drive command for operating the MOSFET 11 and outputs it to the drive circuit. The control circuit generates the drive command based on, for example, a torque request input from a higher-level ECU (not shown) and signals detected by various sensors. ECU is an abbreviation for Electronic Control Unit.

[0027] The various sensors include, for example, a current sensor, a rotation angle sensor, and a voltage sensor. The current sensor detects the phase current flowing through the winding 3a of each phase. The rotation angle sensor detects the rotation angle of the rotor of the motor generator 3. The voltage sensor detects the voltage across the smoothing capacitor 5. The control circuit outputs, for example, a PWM signal as a drive command. The control circuit is configured with, for example, a processor and a memory. PWM is an abbreviation for Pulse Width Modulation.

[0028] <Power conversion device> Fig. 2 shows an example of a power conversion device including a capacitor module, and Fig. 3 is a cross-sectional view taken along line III-III in Fig. 2.

[0029] The power conversion device 20 provides the above-described power conversion circuit 4. The power conversion device 20 includes a housing 21, a semiconductor module 22, a capacitor module 23, and a busbar unit 24. The illustrated power conversion device 20 includes a plurality of semiconductor modules 22. First, the elements of the power conversion device 20 other than the capacitor module 23 will be described.

[0030] In the following, the height direction of the capacitor element is referred to as the Z direction. The direction perpendicular to the Z direction is referred to as the X direction, and the direction perpendicular to both the X and Z directions is referred to as the Y direction. The X, Y, and Z directions are mutually orthogonal. Unless otherwise specified, the shape viewed from the Z direction, in other words, the shape along the XY plane defined by the X and Y directions, is referred to as the planar shape. The planar view from the Z direction is sometimes simply referred to as the planar view.

[0031] The housing 21 houses other elements that make up the power conversion device 20. The housing 21 may be a metal housing made of a metal material such as aluminum, or a resin housing made of a resin material. It may also be a housing containing a metal material and a resin material. To dissipate heat generated by the semiconductor module 22, the capacitor module 23, etc., it is preferable to use a housing containing a metal material, more preferably a metal housing. The housing 21 may be made of a single member or may be made of a combination of multiple members.

[0032] The illustrated housing 21 has a base 211 and a side wall 212. The housing 21 is formed using a metal material including aluminum. The base 211 supports a semiconductor module 22 and a capacitor module 23. The semiconductor module 22 and the capacitor module 23 are arranged on one surface of the base 211. The illustrated base 211 forms the bottom wall of the housing 21. The side wall 212 is continuous with the base 211. The side wall 212, together with the base 211, defines a storage section.

[0033] The base 211 provides a cooling function for cooling the semiconductor module 22 and the capacitor module 23. For this reason, the base 211 is sometimes referred to as a cooler. The base 211 may be a heat sink. The heat sink may have fins on the back side. The illustrated base 211 has a flow path 213. An inlet pipe and an outlet pipe (not shown) are connected to the flow path 213, and a refrigerant 214 flows through the flow path 213. The refrigerant 214 may be a phase-change refrigerant such as water or ammonia, or a phase-non-change refrigerant such as an ethylene glycol-based refrigerant. The refrigerant 214 may be, for example, LLC. LLC is an abbreviation for long life coolant.

[0034] The illustrated flow path 213 is provided in a region directly below the semiconductor module 22 and a region directly below the capacitor module 23. The flow path 213 directly below the semiconductor module 22 and the flow path 213 directly below the capacitor module 23 may be connected to each other in a portion not shown, or may be provided independently of each other.

[0035] The semiconductor modules 22 constitute the upper and lower arm circuits 9, i.e., the inverter 6. The semiconductor modules 22 may also be referred to as power modules, semiconductor devices, etc. The power conversion device 20 includes three semiconductor modules 22. The multiple semiconductor modules 22 include a semiconductor module 22U that constitutes the upper and lower arm circuits 9U, a semiconductor module 22V that constitutes the upper and lower arm circuits 9V, and a semiconductor module 22W that constitutes the upper and lower arm circuits 9W.

[0036] The semiconductor modules 22 have, for example, a common structure. Each semiconductor module 22 includes a main body 221 and external connection terminals protruding from the main body 221. The main body 221 includes semiconductor elements 222H and 222L, a sealing body 223, and the like.

[0037] The semiconductor elements 222H and 222L are formed by forming switching elements on semiconductor substrates made of materials such as silicon (Si) or wide-bandgap semiconductors with a wider bandgap than silicon. The switching elements have a vertical structure so that the main current flows in the thickness direction of the semiconductor substrate. Examples of wide-bandgap semiconductors include silicon carbide (SiC), gallium nitride (GaN), gallium oxide (Ga2O3), and diamond.

[0038] The illustrated semiconductor elements 222H, 222L are formed by forming the above-described n-channel MOSFET 11 and diode 12 on a semiconductor substrate made of SiC. The MOSFET 11 has a vertical structure so that a main current flows in the thickness direction of the semiconductor elements 222H, 222L (semiconductor substrate). The semiconductor elements 222H, 222L have main electrodes (not shown) on both sides in the thickness direction. The semiconductor elements 222H, 222L have a source electrode on the front surface and a drain electrode on the back surface as main electrodes. The source electrode is formed on a portion of the front surface. The drain electrode is formed on almost the entire back surface.

[0039] The main current flows between the drain electrode and the source electrode. The semiconductor elements 222H, 222L have pads (not shown) that are signal electrodes on the surface where the source electrode is formed. The semiconductor elements 222H, 222L are arranged so that their plate thickness direction is approximately parallel to the Z direction. One semiconductor module 22 includes two semiconductor elements 222H that form the upper arm 9H and two semiconductor elements 222L that form the lower arm 9L. The semiconductor elements 222H, 222L are aligned in the X direction. The two semiconductor elements 222H are aligned in the Y direction. Similarly, the two semiconductor elements 222L are aligned in the Y direction.

[0040] The sealing body 223 seals some of the other elements that make up the semiconductor module 22. The remaining parts of the other elements are exposed to the outside of the sealing body 223. The sealing body 223 seals the semiconductor elements 222H, 222L and parts of the external connection terminals. Other parts of the external connection terminals protrude outside the sealing body 223. The sealing body 223 is made of, for example, resin. The sealing body 223 is molded by transfer molding using, for example, epoxy resin. The sealing body 223 has a generally rectangular shape in plan view with the longitudinal direction in the X direction. The sealing body 223 forms the outer periphery of the main body 221.

[0041] The external connection terminals are terminals for electrically connecting the semiconductor module 22 to an external device. The external connection terminals include a P-terminal 224P, an N-terminal 224N, and an O-terminal 224O as main terminals electrically connected to the main electrodes of the semiconductor elements 222H and 222L. The P-terminal 224P is electrically connected to the drain electrode of the semiconductor element 222H. The N-terminal 224N is electrically connected to the source electrode of the semiconductor element 222L. The P-terminal 224P and the N-terminal 224N protrude to the outside from the side surface of the main body 221 facing the capacitor module 23. The protruding portions of the P-terminal 224P and the N-terminal 224N are aligned in the Y direction.

[0042] The O terminal 224O is electrically connected to the connection point (midpoint) between the source electrode of the semiconductor element 222H and the drain electrode of the semiconductor element 222L. The O terminal 224O protrudes to the outside from the side surface of the main body 221 opposite to the side surface from which the P terminal 224P and the N terminal 224N protrude. The O terminal 224O protrudes to the outside from the side surface opposite to the surface facing the capacitor module 23. The O terminal 224O is connected to the corresponding winding 3a of the motor generator 3, for example, via an output terminal block (not shown). In addition to the above-mentioned terminals, the external connection terminals also include signal terminals (not shown).

[0043] In addition to the above-mentioned elements, the semiconductor module 22 also includes wiring members (not shown). The wiring members provide a wiring function that electrically connects the main electrodes and main terminals of the semiconductor elements 222H, 222L. The wiring members provide a heat dissipation function that dissipates heat from the semiconductor elements 222H, 222L. The wiring members may be, for example, a substrate with metal bodies arranged on both sides of an insulating base material, or may be a heat sink that is a metal member. The heat sink may be provided as part of the lead frame. The wiring members may be entirely sealed with the sealing body 223, or may be partially exposed from the main body 221. Exposing the wiring members can improve heat dissipation.

[0044] The semiconductor module 22 described above is disposed on a base 211. A main body 221 of the semiconductor module 22 may be fixed to the base 211 via a bonding material, or may be thermally connected to the base 211 via a TIM (thermal interface material). TIM is an abbreviation for Thermal Interface Material.

[0045] 2, the three semiconductor modules 22 are lined up in the Y direction. The three semiconductor modules 22 are lined up in the order of semiconductor module 22U, semiconductor module 22V, and semiconductor module 22W. In addition, the side surfaces of adjacent semiconductor modules 22 face each other in the Y direction with a predetermined gap therebetween.

[0046] The busbar unit 24 is a wiring member that electrically connects the semiconductor module 22 and the capacitor module 23. The busbar unit 24 may also be referred to as a busbar assembly, a busbar subassembly, etc. The busbar unit 24 includes a P busbar 241P, an N busbar 241N, and an insulating member 242.

[0047] P bus bar 241P and N bus bar 241N are metal plates made of a metal with good conductivity, such as Cu. P bus bar 241P electrically connects P terminal 224P of semiconductor module 22 to P bus bar 50P of capacitor module 23. N bus bar 241N electrically connects N terminal 224N of semiconductor module 22 to N bus bar 50N of capacitor module 23. To reduce inductance, P bus bar 241P and N bus bar 241N are arranged so that their plate surfaces face each other over a portion of their entire lengths.

[0048] Insulating member 242 is interposed between P bus bar 241P and N bus bar 241N, and insulates and separates P bus bar 241P from N bus bar 241N. Insulating member 242 is, for example, a resin molded body.

[0049] The P bus bar 241P and the N bus bar 241N are connected to the corresponding main terminals and capacitor bus bar 50 by, for example, laser welding. To enable laser welding, the P bus bar 241P is provided with a through hole 243. The through hole 243 is an opening provided for laser welding the N bus bar 241N located below the P bus bar 241P to the N bus bar 50N.

[0050] <Capacitor module> 4 is a cross-sectional view showing an example of a capacitor module, and is an enlarged view of the capacitor module and its surrounding area in the power converter shown in FIG.

[0051] The capacitor module 23 provides the above-mentioned smoothing capacitor 5. The capacitor module 23 includes a capacitor element 30, a capacitor case 40, a capacitor bus bar 50, and a sealing resin body 60. The capacitor module 23 is arranged side by side with the semiconductor module 22 in the X direction.

[0052] The capacitor element 30 is, for example, a film capacitor element. The capacitor element 30 is formed by winding a film around an axis that is approximately parallel to the Z direction. The capacitor element 30 has a substantially rectangular shape in plan view. The capacitor element 30 has one surface 301, a back surface 302, and a side surface 303. The back surface 302 is the surface opposite to the one surface 301 in the Z direction. The side surface 303 is a surface that is continuous with the one surface 301 and the back surface 302. The capacitor element 30 has electrodes 31 on the one surface 301 and the back surface 302. The electrodes 31 are sometimes referred to as metallikon electrodes, etc. The exemplary capacitor element 30 has, as the electrodes 31, a positive P-electrode 31P on the one surface 301 and a negative N-electrode 31N on the back surface 302.

[0053] The capacitor module 23 includes a plurality of capacitor elements 30. The capacitor elements 30 are aligned in at least one direction perpendicular to the Z direction. In the illustrated capacitor module 23, the plurality of capacitor elements 30 are aligned in at least the X direction.

[0054] The capacitor case 40 may be formed using a metal material such as aluminum, or a resin material such as PPS or PBT. The capacitor case 40 has a cylindrical shape with a bottom. The capacitor case 40 has a bottom wall 41 and a side wall 42. The capacitor case 40 houses a plurality of capacitor elements 30. The bottom wall 41 faces the back surface 302 of the capacitor element 30 in the Z direction. In other words, the bottom wall 41 faces the N-electrode 31N.

[0055] The capacitor case 40 has a cooling surface 43 that is thermally connected to a cooler. In the illustrated capacitor case 40, a base 211, which is a cooler, is thermally connected to the bottom wall 41. The capacitor case 40 is, for example, joined to the base 211. The outer surface of the bottom wall 41 forms the cooling surface 43. A flow path 213 is provided directly below the bottom wall 41.

[0056] The capacitor bus bars 50 are metal plates made of a metal with good conductivity, such as Cu. The capacitor bus bars 50 are connected to corresponding electrodes 31. A portion of each capacitor bus bar 50 is sealed by the sealing resin body 60, and another portion protrudes outside the sealing resin body 60.

[0057] The capacitor bus bar 50 includes a P bus bar 50P connected to the P electrode 31P and an N bus bar 50N connected to the N electrode 31N. The P bus bar 50P has an electrode connection portion 51P, a terminal portion 52P, and a linking portion 53P. In the P bus bar 50P, the electrode connection portion 51P is a portion that connects to the P electrode 31P. The terminal portion 52P is a portion that connects to the P bus bar 241P of the bus bar unit 24. The linking portion 53P is a portion that connects the electrode connection portion 51P and the terminal portion 52P.

[0058] The electrode connection portion 51P is covered by the sealing resin body 60. The terminal portion 52P is disposed outside the sealing resin body 60. A portion of the connecting portion 53P is covered by the sealing resin body 60, and the remaining portion protrudes outside the sealing resin body 60. The plate thickness direction of the connecting portion 53P is approximately parallel to the X direction and extends in the Z direction. The electrode connection portion 51P extends from one end of the connecting portion 53P in the X direction to the side opposite the semiconductor module 22. The terminal portion 52P extends from the other end of the connecting portion 53P in the X direction to the side opposite the semiconductor module 22.

[0059] Like the P bus bar 50P, the N bus bar 50N also has an electrode connection portion 51N, a terminal portion 52N, and a linking portion 53N. In the N bus bar 50N, the electrode connection portion 51N is a portion that connects to the N electrode 31N. The terminal portion 52N is a portion that connects to the N bus bar 241N of the bus bar unit 24. The linking portion 53N is a portion that connects the electrode connection portion 51N and the terminal portion 52N.

[0060] The electrode connection portion 51N is covered by the sealing resin body 60. The terminal portion 52N is disposed outside the sealing resin body 60. Most of the connecting portion 53N is covered by the sealing resin body 60, with the remaining portion protruding outside the sealing resin body 60. The connecting portion 53N has a plate thickness direction that is approximately parallel to the X direction and extends in the Z direction. The electrode connection portion 51N extends from one end of the connecting portion 53N in the X direction toward the opposite side to the semiconductor module 22. The terminal portion 52N extends from the other end of the connecting portion 53N in the X direction toward the semiconductor module 22.

[0061] The N bus bar 50N further has an intervening portion 54N. The intervening portion 54N is interposed between the opposing surfaces of the capacitor elements 30 aligned in a predetermined direction. The illustrated intervening portion 54N is interposed between the side surfaces 303 of the capacitor elements 30 aligned in the X direction. The intervening portion 54N is continuous with the electrode connecting portion 51N and extends in the Z direction. The intervening portion 54N extends above the center position of the capacitor element 30 in the height direction. The intervening portion 54N is insulated from the P bus bar 50P by the sealing resin body 60. The intervening portion 54N is in contact (close contact) with each of the opposing side surfaces 303.

[0062] The sealing resin body 60 is formed using an electrically insulating resin material such as epoxy resin. The illustrated sealing resin body 60 is formed by potting. The sealing resin body 60 is filled into the capacitor case 40 and seals the capacitor elements 30. The sealing resin body 60 seals a portion of the capacitor bus bar 50. The capacitor module 23 may also include an insulating member (not shown). The insulating member is disposed at the opposing portion of the P bus bar 50P and the N bus bar 50N that protrudes from the sealing resin body 60.

[0063] <Summary of the First Embodiment> The capacitor module 23 of this embodiment includes a plurality of capacitor elements 30 arranged in a predetermined direction, a capacitor case 40, a plurality of capacitor bus bars 50, and a sealing resin body 60. At least one of the plurality of capacitor bus bars 50 has an intervening portion interposed between opposing surfaces of adjacent capacitor elements 30. At any position in one direction perpendicular to the predetermined direction, only one intervening portion is disposed between the opposing surfaces.

[0064] In this way, because the intervening portion of the capacitor bus bar 50 is disposed between the opposing surfaces of adjacent capacitor elements 30, heat generated by the capacitor elements 30 can be dissipated through the condenser bus bar 50. This heat dissipation can lower the temperature at the center of the element. Furthermore, at any position in one direction perpendicular to the predetermined direction, only one intervening portion exists between the opposing surfaces. In other words, at any position, only one condenser bus bar 50 is disposed between the opposing surfaces. Because there is no need to add a component for heat dissipation (cooling) to the capacitor module 23, heat dissipation performance can be improved while suppressing an increase in the number of parts. In other words, heat dissipation performance can be improved while simplifying the configuration.

[0065] Furthermore, since only one capacitor bus bar 50 is disposed between the opposing surfaces at any position, it is possible to improve heat dissipation while suppressing an increase in the physical size in a predetermined direction.

[0066] As shown in the example, the one direction may be the Z direction, which is the height direction of the capacitor element 30, and the predetermined direction may be a direction perpendicular to the Z direction. A configuration may also be adopted in which a P electrode 31P is provided on one surface 301 in the height direction of the capacitor element 30, and an N electrode 31N is provided on a back surface 302, with the side surfaces 303 facing each other. It is preferable that at least one of the P bus bar 50P connected to the P electrode 31P and the N bus bar 50N connected to the N electrode 31N has an interposition portion. In the example capacitor module 23, the N bus bar 50N has an interposition portion 54N. This allows the capacitor module 23 to achieve the above-described effects while employing a general structure used in vehicles.

[0067] As illustrated, an interposition portion may be provided on the condenser bus bar 50 of the P bus bar 50P and the N bus bar 50N that is positioned closer to the cooling surface 43 of the capacitor case 40. In the illustrated capacitor module 23, an interposition portion 54N is provided on the N bus bar 50N on the cooling surface 43 side. In this way, the interposition portion of the condenser bus bar 50 that is cooled more by the cooler (base 211) is positioned between the side surfaces 303 of the capacitor elements 30, which promotes heat transfer from the capacitor elements 30 to the condenser bus bar 50, thereby further improving heat dissipation.

[0068] As illustrated, the bottom wall 41 of the capacitor case 40 may have a cooling surface 43. An intervening portion may be provided in the capacitor bus bar 50 connected to the electrode 31 facing the bottom wall 41. The intervening portion is continuous with the electrode connection portion connected to the electrode 31 facing the bottom wall 41, extends in the height direction, and is interposed between the side surfaces 303. In this way, since the intervening portion is close to the cooler (base 211), heat transfer from the capacitor element 30 to the capacitor bus bar 50 is further promoted, and heat dissipation can be further improved.

[0069] <Modification> Although an example has been shown in which the N bus bar 50N has the interposed portion 54N, this is not limiting. Instead of the N bus bar 50N, the P bus bar 50P may have the interposed portion. The capacitor bus bar 50 is thermally connected to the semiconductor module 22. Since the semiconductor module 22 is cooled by the cooler (base 211), heat from the capacitor element 30 can be dissipated through the P bus bar 50P.

[0070] Although an example has been shown in which the electrode 31 on the bottom wall 41 side is the N-electrode 31N, this is not limiting. The P-electrode 31P may be provided on the back surface 302 on the bottom wall 41 side. An interposed portion may be provided on the P-bus bar 50P close to the cooling surface 43.

[0071] Although an example has been shown in which base 211, which is a cooler, has flow path 213, the present invention is not limited to this. A configuration may be adopted in which flow path 213 is not provided directly below capacitor module 23. A configuration in which base 211 does not have a flow path may also be adopted.

[0072] Although an example has been shown in which only one intervening portion is disposed between the opposing surfaces of the capacitor element 30 at an arbitrary position in one direction perpendicular to the predetermined direction, this is not limiting. A configuration in which one intervening portion and a portion of the sealing resin body 60 that is thinner than the intervening portion may also be disposed. In the example shown in FIG. 5 , the intervening portion 54N of the N bus bar 50N and the sealing resin body 60 are disposed between the side surfaces 303. The sealing resin body 60 interposed between the side surfaces 303 and the intervening portion 54N is thinner than the intervening portion 54N. Although the intervening portion 54N does not contact the side surfaces 303, the intervening sealing resin body 60 is thin, so heat generated by the capacitor element 30 can be dissipated through the intervening portion 54N (N bus bar 50N). Because only the capacitor bus bar 50 and the sealing resin body 60 that constitute the capacitor module 23 are interposed between the side surfaces 303, heat dissipation can be improved while simplifying the configuration.

[0073] Although an example in which the capacitor case 40 is joined to the base 211 has been shown, this is not limiting. The capacitor module 23 may be arranged in contact with the cooling surface 43 of the capacitor case 40, and may include a thermally conductive member interposed between the capacitor case 40 (cooling surface 43) and the cooler. In the example shown in FIG. 6, a thermally conductive member 70 is arranged between the cooling surface 43 of the bottom wall 41 and the base 211. The thermally conductive member 70 may also be referred to as a TIM, GF, or the like. GF is an abbreviation for Gap Filler. The thermally conductive member 70 thermally connects the capacitor case 40 and the base 211. This cools the condenser bus bar 50 close to the cooling surface 43, facilitating heat transfer from the capacitor elements 30 to the condenser bus bar 50.

[0074] (Second embodiment) This embodiment is a modification based on the previous embodiment, and the description of the previous embodiment can be used. In the previous embodiment, the outer surface of the bottom wall is used as the cooling surface. Alternatively, or in addition, the outer surface of the side wall may be used as the main cooling surface.

[0075] Fig. 7 is a cross-sectional view showing an example of a capacitor module according to this embodiment. Fig. 7 corresponds to Fig. 4. Fig. 7 is an enlarged view of the capacitor module and its surrounding area in the power conversion device.

[0076] The capacitor module 23 has a main cooling surface 43 on the outer surface of the side wall 42 of the capacitor case 40. The base 211, which is a cooler, has a flow path 213 in the area directly below the semiconductor module 22 (not shown). The base 211 does not have a flow path 213 in the area directly below the capacitor module 23. The end of the base 211 in the area directly below the semiconductor module 22 is thermally connected to the side wall 42 of the capacitor case 40. The outer surface of the side wall 42 is the cooling surface 43 that is cooled by the refrigerant 214 flowing in the flow path 213.

[0077] The connecting portion 53N of the N bus bar 50N is disposed near the side wall 42 that is thermally connected to the base 211. The N bus bar 50N close to the cooling surface 43 is cooled, and heat transfer from the capacitor element 30 to the N bus bar 50N is promoted.

[0078] The outer surface of the bottom wall 41 is also thermally connected to the region of the base 211 directly below the capacitor module 23. The outer surface of the bottom wall 41 also forms a cooling surface 43. The N bus bar 50N is effectively cooled by the effects of the cooling surfaces 43 of the side walls 42 and the bottom wall 41. The other configurations are the same as those described in the preceding embodiment.

[0079] <Summary of the second embodiment> As illustrated, the cooling surface 43 may be provided on the side wall 42 of the capacitor case 40. By providing an interposition portion on the capacitor bus bar 50 arranged near the cooling surface 43 of the side wall 42, heat dissipation can be further improved.

[0080] As shown in the example, cooling surfaces 43 may be provided on both the bottom wall 41 and the side wall 42. The cooling surfaces 43 on the side wall 42 and the condenser bus bar 50 close to the cooling surfaces 43 on the bottom wall 41 are effectively cooled, further promoting heat transfer from the capacitor elements 30 to the condenser bus bar 50. This further improves heat dissipation.

[0081] (Third embodiment) This embodiment is a modification based on the preceding embodiment, and the description of the preceding embodiment can be used. In the preceding embodiment, no particular mention was made of the connection structure between the electrode connection portion and the interposition portion. The connection structure shown in this embodiment may be adopted.

[0082] Fig. 8 is a plan view showing the structure of a bus bar having an interposed portion in a capacitor module according to this embodiment. Fig. 8 shows a portion of the bus bar, specifically, the electrode connection portion and the interposed portion. Fig. 9 is a cross-sectional view taken along line IX-IX in Fig. 8.

[0083] The N bus bar 50N shown in FIGS. 8 and 9 is formed by processing a single metal plate. The electrode connection portion 51N and the intervening portion 54N are not integrated by joining, but are provided as a continuous, integrated unit. The intervening portion 54N is bent relative to the electrode connection portion 51N. A notch 55 is provided in a part of the flat plate including the electrode connection portion 51N, and the portion where the three strands are separated by the notch 55 is bent at an angle of approximately 90 degrees to form the intervening portion 54N. The other configurations are the same as those described in the preceding embodiment.

[0084] <Summary of the third embodiment> As shown in the example, the electrode connection portion 51N and the interposing portion 54N may be provided as a continuous, integral unit, with the interposing portion 54N bent relative to the electrode connection portion 51N. This allows the N bus bar 50N to be formed by processing a single metal plate, further simplifying the configuration. Note that while an example of the N bus bar 50N has been shown, the same applies when an interposing portion is provided on the P bus bar 50P.

[0085] <Modification> In the capacitor bus bar 50, the connection structure between the electrode connection portions and the intervening portions is not limited to the above example. The capacitor bus bar 50 having the intervening portion may be configured by joining a first plate material including the electrode connection portions and a second plate material including the intervening portion. In the example shown in Fig. 10, the N bus bar 50N is configured by joining a plate material 56 including the electrode connection portions 51N and a plate material 57 including the intervening portion 54N. The planar shape of the plate material 57 along the ZX plane is approximately L-shaped, and one side of the L shape is joined to the plate material 56.

[0086] (Fourth embodiment) This embodiment is a modification based on the previous embodiment, and the description of the previous embodiment can be used. In the previous embodiment, an interposing portion is provided on either the P bus bar or the N bus bar. Alternatively, an interposing portion may be provided on both the P bus bar and the N bus bar.

[0087] Fig. 11 is a cross-sectional view showing an example of a capacitor module according to this embodiment. Fig. 11 corresponds to Fig. 4. Fig. 11 is an enlarged view of the capacitor module and its surrounding area in the power conversion device.

[0088] Similar to the configuration shown in the first embodiment (see FIG. 4), the capacitor module 23 has a cooling surface 43 on the bottom wall 41. An N-electrode 31N is provided on the back surface 302 facing the bottom wall 41. An N-bus bar 50N connected to the N-electrode 31N has an interposed portion 54N. The interposed portion 54N is disposed between the back surface 302 and the side surface 303 of the capacitor element 30.

[0089] A P electrode 31P is provided on one surface 301. The P bus bar 50P connected to the P electrode 31P also has an intervening portion 54P. The intervening portion 54P is continuous with the electrode connection portion 51P and extends in the Z direction. The intervening portion 54P is disposed between the one surface 301 and the side surface 303 of the capacitor element 30. The intervening portion 54P and the intervening portion 54N are disposed at different positions in the Z direction so as not to overlap in the X direction, which is the arrangement direction. The intervening portion 54N of the N bus bar 50N closer to the cooling surface 43 is longer in the Z direction than the intervening portion 54P. The other configurations are the same as those described in the preceding embodiment.

[0090] <Summary of the Fourth Embodiment> As illustrated, the P bus bar 50P may have an intervening portion 54P, and the N bus bar 50N may have an intervening portion 54N. The intervening portion 54P (P intervening portion) and the intervening portion 54N (N intervening portion) may be disposed at different positions in the height direction so as not to overlap in a predetermined direction. This allows for a simple configuration while enhancing the heat dissipation effect by utilizing both the P bus bar 50P and the N bus bar 50N. For example, the P bus bar 50P is thermally connected to the semiconductor module 22, and the semiconductor module 22 is cooled by the cooler (base 211). This allows for heat dissipation from the capacitor element 30 through the P bus bar 50P. Furthermore, as described in the preceding embodiment, the N bus bar 50N disposed near the cooling surface 43 can effectively dissipate heat from the capacitor element 30. Furthermore, because the intervening portions 54P and 54N do not overlap in a predetermined direction, the heat dissipation effect can be enhanced while suppressing an increase in the overall size.

[0091] As shown in the example, the interposition portion of the first bus bar, of the P bus bar 50P and the N bus bar 50N, that is closer to the cooling surface 43 may be longer in the Z direction than the interposition portion of the second bus bar that is farther from the cooling surface 43. In the example capacitor module 23, the interposition portion 54N is longer in the Z direction than the interposition portion 54P. In this way, the condenser bus bar 50 that is closer to the cooling surface 43 has a greater effect in dissipating heat from the capacitor element 30. By lengthening the interposition portion of the condenser bus bar 50 that has a high heat dissipation effect (cooling effect), it is possible to further improve heat dissipation performance.

[0092] <Modification> Although the example in which the intervening portions 54P and 54N are disposed between the common side surfaces 303 has been shown, the present invention is not limited to this and they may be disposed between different side surfaces 303.

[0093] For example, multiple capacitor elements 30 may be arranged in a matrix so as to be aligned in a first direction orthogonal to the height direction and aligned in a second direction orthogonal to both the height direction and the first direction. In such an arrangement, an intervening portion 54P (P intervening portion) of a P bus bar 50P may be arranged between opposing surfaces of adjacent capacitor elements 30 in the first direction, and an intervening portion 54N (N intervening portion) of an N bus bar 50N may be arranged between opposing surfaces of adjacent capacitor elements 30 in the second direction. In the example shown in Fig. 12, an intervening portion 54P is arranged between adjacent side surfaces 303 in the X direction, and an intervening portion 54N is arranged between adjacent side surfaces 303 in the Y direction.

[0094] The intervening portions 54P, 54N are cross-shaped in plan view. The intervening portions 54P, 54N have portions that cross in a cross shape in plan view. With this arrangement, heat can be efficiently dissipated regardless of whether heat is likely to build up in the X direction or the Y direction.

[0095] In the arrangement of capacitor element 30 shown in FIG. 12, intervening portion 54N may be arranged between side surfaces 303 adjacent to each other in the X direction, and intervening portion 54P may be arranged between side surfaces 303 adjacent to each other in the Y direction.

[0096] (Other embodiments) The disclosure in this specification and drawings, etc. is not limited to the exemplified embodiments. The disclosure encompasses the exemplified embodiments and modifications thereto by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and / or elements shown in the embodiments. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure encompasses the omission of parts and / or elements from the embodiments. The disclosure encompasses the substitution or combination of parts and / or elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. Some disclosed technical scopes are defined by the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the claims.

[0097] The disclosure in the specification, drawings, etc. is not limited by the claims. The disclosure in the specification, drawings, etc. encompasses the technical ideas described in the claims, and extends to more diverse and broader technical ideas than the technical ideas described in the claims. Therefore, various technical ideas can be extracted from the disclosure in the specification, drawings, etc. without being bound by the claims.

[0098] When an element or layer is referred to as being "on," "coupled," "connected," or "bonded," it may be directly on, coupled, connected, or bonded to another element or layer, and intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly coupled," "directly connected," or "directly bonded" to another element or layer, no intervening elements or layers are present. Other terms used to describe relationships between elements should be construed in a similar manner (e.g., "between" vs. "directly between," "adjacent" vs. "directly adjacent," etc.). As used in this specification, the term "and / or" includes any and all combinations of one or more of the associated listed items. That is, reference to A and / or B means at least one of A and B.

[0099] Spatially relative terms such as "inside," "outside," "back," "below," "low," "top," "top," and the like are used herein to facilitate the description of one element or feature's relationship to other elements or features, as illustrated. Spatially relative terms may be intended to encompass different orientations of the device during use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures were turned over, elements described as "below" or "directly below" other elements or features would then be oriented "above" the other elements or features. Thus, the term "bottom" can encompass both an orientation of top and bottom. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used in this specification would be interpreted accordingly.

[0100] Although the example in which the base 211, which is a part of the housing 21, serves as a cooler has been shown, the present invention is not limited to this. A cooler separate from the housing 21 may also be used. [Explanation of symbols]

[0101] 1... drive system, 2... DC power supply, 3... motor generator, 3a... winding, 4... power conversion circuit, 5... smoothing capacitor, 6... inverter, 7... P line, 8... N line, 9, 9U, 9V, 9W... upper and lower arm circuits, 9H... upper arm, 9L... lower arm, 10... output line, 11... MOSFET, 12... diode, 20... power conversion device, 21... housing, 211... base, 212... side wall, 213... flow path, 214... refrigerant, 22, 22U, 22V, 22W... semiconductor module, 221... main body, 222H, 222L... semiconductor element, 223... sealing body, 224N... N terminal, 224O... O terminal, 224P... P terminal 23...capacitor module, 24...busbar unit, 241N...N busbar, 241P...P busbar, 242...insulating member, 243...through hole, 30...capacitor element, 301...one surface, 302...rear surface, 303...side surface, 31...electrode, 31N...N electrode, 31P...P electrode, 40...capacitor case, 41...bottom wall, 42...side wall, 43...cooling surface, 50...capacitor busbar, 50N...N busbar, 50P...P busbar, 51N, 51P...electrode connection portion, 52N, 52P...terminal portion, 53N, 53P...connecting portion, 54N, 54P...interposition portion, 55...notch, 56, 57...plate material, 60...encapsulating resin body, 70...thermal conductive member

Claims

1. A plurality of capacitor elements (30) arranged in a predetermined direction; a capacitor case (40) that houses a plurality of the capacitor elements; a plurality of capacitor bus bars (50) electrically connected to the capacitor elements; a sealing resin body (60) disposed in the capacitor case and sealing the capacitor element and a portion of each of the plurality of capacitor bus bars; Equipped with At least one of the plurality of capacitor bus bars has an interposition portion (54N, 54P) interposed between opposing surfaces of adjacent capacitor elements, A capacitor module in which, at any position in one direction perpendicular to the specified direction, only one of the intervening portions, or one of the intervening portions and a portion of the sealing resin body that is thinner than the intervening portion, is arranged between the opposing surfaces.

2. the one direction is a height direction of the capacitor element, Each of the plurality of capacitor elements has, as electrodes (31), a P-electrode (31P) formed on one surface and an N-electrode (31N) formed on a back surface that is the surface opposite to the one surface in the height direction; the plurality of capacitor bus bars include a P bus bar (50P) connected to the P electrode and an N bus bar (50N) connected to the N electrode, the opposing surface is a side surface connected to the one surface and the back surface, The capacitor module according to claim 1 , wherein at least one of the P bus bar and the N bus bar has the interposed portion.

3. The capacitor case has a cooling surface (43) thermally connected to a cooler (211); The capacitor module according to claim 2 , wherein one of the P bus bar and the N bus bar that is positioned closer to the cooling surface has the interposed portion.

4. the capacitor case has the cooling surface on a bottom wall facing the P electrode or the N electrode in the height direction, the bus bar having the interposed portion has an electrode connection portion (51N) connected to the electrode facing the bottom wall, The capacitor module according to claim 3 , wherein the interposing portion is continuous with the electrode connecting portion, extends in the height direction, and is interposed between the side surfaces.

5. the electrode connection portion and the interposition portion are provided continuously and integrally, The capacitor module according to claim 4 , wherein the interposition portion is bent relative to the electrode connection portion.

6. 5. The capacitor module according to claim 4, wherein the bus bar having the interposed portion is formed by joining a first plate member (56) including the electrode connection portion and a second plate member (57) including the interposed portion.

7. the P bus bar and the N bus bar both have the interposed portion, 3. The capacitor module according to claim 2, wherein a P interposition portion that is the interposition portion of the P bus bar and an N interposition portion that is the interposition portion of the N bus bar are disposed at different positions in the height direction so as not to overlap in the predetermined direction.

8. The capacitor case has a cooling surface (43) thermally connected to a cooler (211); 8. The capacitor module according to claim 7, wherein the interposed portion of a first bus bar, of the P bus bar and the N bus bar, that is closer to the cooling surface, has a longer length in the height direction than the interposed portion of a second bus bar that is farther from the cooling surface than the first bus bar.

9. the plurality of capacitor elements are arranged in a matrix so as to be aligned in a first direction perpendicular to the height direction and to be aligned in a second direction perpendicular to both the height direction and the first direction; the P interposition portion is interposed between opposing surfaces of the capacitor elements adjacent to each other in the first direction, The capacitor module according to claim 7 , wherein the N interposition portion is interposed between opposing surfaces of the capacitor elements adjacent to each other in the second direction.

10. The capacitor module according to claim 9 , wherein the P interposition portion and the N interposition portion are arranged to form a cross shape in a plan view in the height direction.

11. 5. The capacitor module according to claim 3, further comprising a heat-conducting member (70) disposed in contact with the cooling surface and interposed between the capacitor case and the cooler.

Images