ELECTRICAL CIRCUIT BODY, POWER CONVERTER AND METHOD FOR MANUFACTURING AN ELECTRICAL CIRCUIT BODY

Abstract

Electrical circuit body comprising: a circuit body (310) having a first power semiconductor element (155) sandwiched between a first circuit board (430) on one surface thereof and a second circuit board (431) on the other surface thereof; a cooling member (340) arranged on both surfaces of the circuit body (310); a sheet-shaped member (440) adhered to at least the second circuit board (431) and having at least one resin insulating layer (441); and a metal-based heat conduction member (450) provided between the sheet-shaped member (440) and the cooling member (340) in such a way that it is in contact with the sheet-shaped member (440) and with the cooling member (340); wherein the metal-based heat conduction member (450) has an adhesive member (460) provided on an outer periphery thereof and sealing the outer periphery of the metal-based heat conduction member (450).

Description

Technical field

[0001] The present invention relates to an electrical circuit body, a power converter and a method for producing an electrical circuit body. State of the art

[0002] A power converter using switching of a power semiconductor element has high conversion efficiency and is thus widely available for consumer use, use in vehicles, use in railway vehicles, use in transformation equipment, and the like. Since this power semiconductor element generates heat upon powering, high heat dissipation is required. For example, for use in vehicles, to reduce the size and weight, a high-efficiency device using a water cooling system is adopted. PTL 1 discloses a power module in which heat generated in an IGBT or a diode is transferred to a radiator via a metal interconnection, a ceramic substrate, and a heat transfer layer. Furthermore, the content of PTL 2 discloses a power module comprising a plurality of semiconductor elements, heat spreaders, heat-dissipating blocks, and insulating films. The insulating films are explicitly designed to be larger than their connecting surfaces with the heat spreaders, while the exposed areas of the mounting plates are at least as large as the connecting surfaces of the insulating films with the plates. Furthermore, the power module is stabilized by encapsulating resin.

[0003] Furthermore, PTL 3 also includes a power module having a plurality of semiconductor elements connected to a heat radiator on both sides for heat radiation. Furthermore, the structure of PTL 3 further discloses a potting resin surrounding the power module, which has recesses surrounding the heat radiation surfaces of the heat radiators, and an insulating film covering the entire heat radiation surface. Furthermore, the content of PTL 4 shows a semiconductor device in which graphite foils are arranged between heat sinks of two semiconductor modules and an insulating plate. Furthermore, to prevent said graphite foils from coming into contact with heat generated by the semiconductor element, wall portions are provided on the surface of a power board.

[0004] In addition, PTL 5 specifies a double-sided cooling semiconductor module which is placed near a coolant tube with a flat contact surface via an insulating spacer and fixed in the direction of its thickness by clamping devices.

[0005] Finally, the content of PTL 6 includes a semiconductor device comprising semiconductor elements, a mold resin covering the semiconductor elements, and a metal plate mounted on the mold resin and positioned over the semiconductor elements. Furthermore, a first through-hole penetrating both the metal plate and the mold resin is provided in the thickness of the mold resin. List of citationsPatent literature PTL 1: JP 2018-26370 A PTL 2: JP 2011 - 216 564 A PTL 3: JP 2013 - 258 334 A PTL 4: JP 2017 - 59 606 A PTL 5: JP 2001 - 320 005 A PTL 6: JP 2016 - 136 604 A Summary of the inventionTechnical problem

[0006] The power module described in PTL 1 requires an expensive ceramic substrate. Solution to the problem

[0007] The electric circuit body according to the present invention includes a circuit body having a first power semiconductor element sandwiched between a first circuit board on one surface thereof and a second circuit board on the other surface thereof, a cooling member disposed on both surfaces of the circuit body, a sheet-shaped member adhered to at least the second circuit board and having at least one resin insulating layer, and a metal-based heat conduction member provided between the sheet-shaped member and the cooling member in such a manner as to be in contact with the sheet-shaped member and the cooling member.

[0008] In the method for manufacturing the electric circuit body, the first power semiconductor element is sandwiched between the first circuit board on one surface thereof and the second circuit board on the other surface thereof, the second power semiconductor element is sandwiched between the third circuit board on one surface thereof and the fourth circuit board on the other surface thereof, the sheet-shaped member is adhered to the second circuit board and the fourth circuit board with at least the resin insulating layer to cover at least the second circuit board and the fourth circuit board, the metal-based heat conduction member having regions of different thicknesses along the arrangement direction of the first power semiconductor element and the second power semiconductor element is adhered to the sheet-shaped member, and the cooling member is brought into close contact with the metal-based heat conduction member. Advantageous effects of the invention

[0009] According to the present invention, heat dissipation can be improved without using a ceramic substrate. Brief description of the drawings Fig. 1 is a plan view of an electrical circuit body. Fig. 2 is a cross-sectional view of the electrical circuit body taken along line XX. Fig. 3 is a cross-sectional view of the electric circuit body taken along the line YY. Fig. 4 is a perspective cross-sectional view of a power module taken along line XX. Fig. 5(a) to 5(e) are cross-sectional views illustrating a method of manufacturing an electric circuit body. Fig. 6(f) to 6(h) are cross-sectional views illustrating the method of manufacturing the electric circuit body. Fig. 7(i) to 7(j) are cross-sectional views illustrating a modification 1 of the method for manufacturing the electric circuit body. Fig. 8(k) to 8(n) are cross-sectional views illustrating a modification 2 of the method for manufacturing the electric circuit body. Fig. Figure 9 is a semi-transparent top view of the power module. Fig. 10 is a circuit diagram showing an example of a circuit of the power module. Fig. 11 is a circuit diagram of a power converter using the power module. Fig. 12 is an external perspective view showing an example of the power converter. Fig. 13 is a perspective cross-sectional view of the power converter taken along line XV-XV. Description of embodiments

[0010] Embodiments of the present invention will be described below with reference to the drawings. The following description and drawings are examples for describing the present invention and are omitted and simplified where necessary for clarity of description. The present invention can be embodied in various other forms. Unless otherwise specified, the number of each component may be one or more.

[0011] To facilitate understanding of the invention, the positions, sizes, shapes, ranges, and the like of the components illustrated in the drawings may not represent actual positions, sizes, shapes, ranges, and the like. Thus, the present invention is not necessarily limited to the position, size, shape, range, and the like disclosed in the drawings.

[0012] Fig. 1 is a plan view of an electric circuit body 400 according to the present embodiment, and Fig. 2 is a cross-sectional view of the electrical circuit body 400 along the Fig. Line XX shown in Figure 1. Fig. 3 is a cross-sectional view of the electrical circuit body 400 along the Fig. Line YY shown in Figure 1.

[0013] As in Fig. 1, the electric circuit body 400 includes three power modules 300 and a cooling member 340. The power module 300 has a function of converting direct current and alternating current using a semiconductor element and generates heat by being energized. Thus, the cooling member 340 is configured to cool a coolant by circulating the coolant therethrough. As the coolant, water, an antifreeze fluid in which ethylene glycol is mixed with water, or the like is used. It should be understood that the cooling member 340 may have a configuration in which pin-shaped fins are erected on a base plate of the cooling member 340. Furthermore, the cooling member 340 may be provided with an unevenness at a contact surface with a metal-based heat conduction member 450 to be described later to engage with the metal-based heat conduction member 450.

[0014] The power module 300 includes power terminals through which a high current flows, such as a terminal 315B on the positive electrode side and a terminal 319B on the negative electrode side, which are connected to a capacitor module 500 (see the later-described Fig. 11) of a DC circuit, and a terminal 320B on the AC side connected to motor generators 192 and 194 (see the later described Fig. 11) of an AC circuit. Furthermore, the power module 300 includes signal terminals used to control the power module, such as a lower arm gate signal terminal 325L, a mirror emitter signal terminal 325M, a Kelvin emitter signal terminal 325K, an upper arm gate signal terminal 325U, a mirror emitter signal terminal 325M, and a Kelvin emitter signal terminal 325K.

[0015] As in Fig. As shown in Figure 2, a first active element 155 and a first diode 156 are provided as first power semiconductor elements constituting an upper arm circuit. The first active element 155 is, for example, an IGBT, a MOSFET, or the like; the first diode 156 is unnecessary if it is a MOSFET. The semiconductor material constituting the first active element 155 may be, for example, Si, SiC, GaN, GaO, C, or the like.

[0016] If a body diode of the active element is used, the first diode 156 may be omitted.

[0017] The same applies to a semiconductor material forming a second active element 157 to be described later.

[0018] A collector side of the first active element 155 and a cathode side of the first diode 156 are connected to a first circuit board 430. Solder or a sintered metal can be used for this connection. As long as the first circuit board 430 is made of a material with high electrical conductivity and thermal conductivity, it is not particularly limited, but a copper-based or aluminum-based material is desirable. These materials can be used alone, but may be plated with Ni, Ag, or the like to improve connection properties such as soldering or bonding with a sintered metal.

[0019] An emitter side of the first active element 155 and an anode side of the first diode 156 are connected to a second circuit board 431. That is, the first active element 155 is sandwiched between the first circuit board 430 on one surface thereof and the second circuit board 431 on the other surface thereof, thereby forming a circuit body 310.

[0020] Fig. 4 is a perspective cross-sectional view of the power module 300 along the Fig. 1 and represents a state in which the cooling member 340 and the metal-based heat conducting member 450 have been removed from the electrical circuit body 400. As shown in Fig. 4, the second circuit board 431 has a recess on the outer periphery of a region connected to the first active element 155 and the diode 156 to ensure an insulation distance. To reduce costs, it is desirable that this recess be formed by press working. When a recess is provided by press working, its rear surface is deformed accordingly. Thus, the second circuit board 431, as shown in Fig. 2, has a predetermined amount of deflection, for example, a deflection of 40 µm, on one side in contact with the cooling member 340.

[0021] As in Fig. 3, a second active element 157 and a second diode 158 (see the later described Fig. 9 and Fig. 10) are provided as second power semiconductor elements forming a lower branch circuit. It should be understood that the second diode 158, as shown in Fig. 3, is arranged on the back side of the second active element 157. A collector side of the second active element 157 and a cathode side of the second diode 158 are connected to a third circuit board 432. An emitter side of the second active element 157 and an anode side of the second diode 158 are connected to a fourth circuit board 433. The fourth circuit board 433, similar to the second circuit board 431, has a deflection on the side in contact with the cooling member 340. In addition, since the second circuit board 431 and the fourth circuit board 433 are independent circuit boards, these circuit boards have different inclinations at the time of connection to the power semiconductor elements. As described above, the second circuit board 431 and the fourth circuit board 433 not only have a deflection on the side in contact with the cooling member 340 as a single body by a predetermined deflection amount (e.g.,40 µm), but also have a thickness of 15 mm, as viewed from the first power semiconductor element (the first active element 155) in a direction in which the second power semiconductor element (the second active element 157) is arranged, as shown in FIG. Fig. 3, on the side in contact with the cooling member 340, there is a step difference, the maximum height change being, for example, 120 µm.

[0022] When the second circuit board 431 and the fourth circuit board 433 are contacted with the cooling member 340 via an insulating layer alone, the thickness of the insulating layer generally needs to be increased to 240 μm to accommodate the 120 μm height change caused by the step difference or deflection, if the thickness of the insulating layer capable of ensuring the insulation properties is set to 120 μm. Since the insulating layer has a lower thermal conductivity than the metal, increasing the thickness of the insulating layer increases the thermal resistance and significantly reduces heat dissipation.

[0023] As in Fig. 2, in the present embodiment, in contrast, a sheet-shaped member 440 including a resin insulating layer 441 and a metal foil 442 is used. The sheet-shaped member 440 is deformed following the deflection or step difference in the second circuit board 431 and the fourth circuit board 433, so that the thickness of the resin insulating layer 441 can be set to a constant thickness, e.g., 120 μm, capable of ensuring the insulation properties. By plastically deforming the metal-based heat conduction member 450, e.g., with a metal foil 442, the sheet-shaped member 440 is deformed to a constant thickness, e.g., 120 μm. B. with a thickness of 120 µm, which is sandwiched between the sheet-shaped member 440 and the cooling member 340, the thickness of the metal-based heat conduction member 450 is changed to accommodate the deflection or step difference generated in the second circuit board 431 and the fourth circuit board 433.Compared with the case where the circuit boards are brought into contact with the cooling member 340 via the insulating layer alone, this results in a significant improvement in heat dissipation. As long as the resin insulating layer 441 of the sheet-like member 440 has adhesiveness with the second circuit board 431 and the fourth circuit board 433, it is not particularly limited, but an epoxy resin-based resin insulating layer in which an inorganic powder filler is dispersed is desirable. This is because the adhesiveness and heat dissipation are balanced.

[0024] The circuit body 310 is configured such that the first active element 155 is sandwiched between the first circuit board 430 on one surface thereof and the second circuit board 431 on the other surface thereof, and further, both surfaces of the circuit body 310 are sandwiched between the sheet-shaped members 440, thereby forming the power module 300.

[0025] The sheet-like member 440 may be the resin insulating layer 441 alone, but it is desirable that the metal foil 442 be provided on one side in contact with the metal-based heat conduction member 450. The metal foil 442 is metallically bonded to the metal-based heat conduction member 450. By providing the metal foil 442, there is an effect of preventing the uncured resin insulating layer 441 from being broken when the sheet-like member 440 is deformed following the deflection or step difference in the second circuit board 431 and the fourth circuit board 433. The type of the metal foil 442 is not particularly limited, but an aluminum-based metal foil or a copper-based metal foil is desirable.In particular, the copper-based metal foil has an effect of reducing thermal contact resistance by forming an alloy layer with the metal-based heat conduction member 450. It is desirable that the cooling member 340 be made of aluminum with high thermal conductivity and light weight.

[0026] The cooling member 340 is manufactured by extrusion, forging, brazing or the like.

[0027] As long as the metal-based heat conduction member 450 is a material with a lower yield point at 200°C or lower than that of the cooling member 340, it is not particularly limited, but a material with a lower elastic modulus than the cooling member 340 is more preferable. If the yield point is unclear, the 0.2% proof stress may be used for comparison. This is because the metal-based heat conduction member 450 is plastically deformed by heating and pressurizing the metal-based heat conduction member 450 via the cooling member 340. The plastically deformed metal-based heat conduction member 450 has a deflection amount of the second circuit board 431 or the fourth circuit board 433 along an arrangement direction of the first active element 155 and the first diode 156 and an arrangement direction of the second active element 157 and the second diode 158 (the horizontal direction in Fig. 4) regions with different thicknesses. In addition, it has regions with different thicknesses according to the step difference between the second circuit board 431 and the fourth circuit board 433 along an arrangement direction of the first active element 155 and the second active element 157 and an arrangement direction of the second active element 157 and the second diode 158 (the depth direction in Fig. 2) Areas with different thicknesses.

[0028] As the metal-based heat conduction member 450, an aluminum-based alloy, a tin-based alloy, a magnesium-based alloy, an indium-based alloy, a silver-based alloy, a gold-based alloy, or pure metals thereof can be used. Among them, indium is preferable because indium, although expensive, has a low elastic modulus and a low yield point. On the other hand, the tin-based alloy is most preferable because it has a higher elastic modulus and a higher yield point than indium and a lower elastic modulus and a lower yield point than the aluminum-based cooling member.

[0029] The power module 300 is formed such that both surfaces of the circuit body 310 are sandwiched between the sheet-shaped members 440, and further, the metal-based heat conduction member 450 is adhered to the sheet-shaped member 440, and the cooling member 340 is brought into close contact with the metal-based heat conduction member 450, thereby forming the electric circuit body 400.

[0030] As in Fig. 2 to 4, the power semiconductor elements and a portion of the first circuit board 430 to fourth circuit board 433 are covered and protected with a potting resin 360 by transfer molding.

[0031] The transfer molding may be performed including the sheet-shaped member 440, or the sheet-shaped member 440 may be adhered after the transfer molding. The transfer molding including the sheet-shaped member 440 has an effect of improving reliability by covering the end portion of the sheet-shaped member 440 with the sealing resin 360.

[0032] As in Fig. 2 and Fig. 3, the outer periphery of the metal-based heat conduction member 450 may be sealed with an adhesive member 460. This allows the metal-based heat conduction member 450 to be kept in close contact with the cooling member 340. Furthermore, sealing with the adhesive member 460 prevents a part of the metal-based heat conduction member 450 from being scattered. By providing a step difference at the outer peripheral portion of the sealing resin 360, it is possible to prevent the adhesive member 460 from entering between the metal-based heat conduction members 450.As long as the adhesive member 460 is an insulating material with adhesiveness, it is not particularly limited, but a material with a thixotropy of 1.5 or higher, obtained by dividing the viscosity at a shear rate of 1 (1 / s) by the viscosity at a shear rate of 10 (1 / s), is desirable to reduce leakage from the applied surface. Among them, a silicone resin or an epoxy resin is desirable. In particular, a silicone resin is desirable because it has a low elastic modulus and thus low thermal stress.

[0033] Fig. 5(a) to 5(e) and Fig. 6(f) to 6(h) are cross-sectional views illustrating a method of manufacturing the electric circuit body 400 of the present embodiment. On the left side of each drawing, the cross section along the Fig. 1 shown line XX and on the right side of each drawing is a power module with the cross section along line YY in Fig. 1 shown.

[0034] Fig. 5(a) illustrates a solder connection process with the first circuit board 430 and the third circuit board 432. The collector side of the first active element 155 and the cathode side of the first diode 156 are connected to the first circuit board 430. Furthermore, the collector side of the second active element 157 and the cathode side of the second diode 158 are connected to the third circuit board 432. It should be understood that the second diode 158 is disposed on the back side of the second active element 157.

[0035] Fig. 5(b) illustrates a wire bonding process. The gate electrodes of the first active element 155 and the second active element 157 are connected.

[0036] Fig. 5(c) illustrates a solder connection process with the second circuit board 431 and the fourth circuit board 433. The emitter side of the first active element 155 and the anode side of the first diode 156 are connected to the second circuit board 431. The emitter side of the second active element 157 and the anode side of the second diode 158 are connected to the fourth circuit board 433. Thus, the circuit body 310 is formed.

[0037] Fig. 5(d) illustrates a press-contact process of the sheet-shaped member 440. The sheet-shaped member 440 is adhered to each circuit board in such a manner that the first circuit board 430 and the third circuit board 432, as well as the second circuit board 431 and the fourth circuit board 433, are accommodated from both sides. Although the sheet-shaped member 440 is configured as one sheet-shaped member 440 for covering the second circuit board 431 and the fourth circuit board 433, separate sheet-shaped members 440 may individually cover the second circuit board 431 and the fourth circuit board 433.

[0038] Fig. 5(e) illustrates a transfer molding process. In a transfer molding device 601 including a spring 602 and a buffer layer 603, the sheet-shaped member 440 covering the second circuit board 431 and the fourth circuit board 433 is integrally molded in the transfer molding process. Furthermore, in the transfer molding process, the sealing resin 360 is pressed by applying pressure to the surface of the sheet-shaped member 440 in such a manner that the sealing resin 360 does not flow around.

[0039] Fig. 6(f) illustrates a fin separation process. The molded product is removed from the transfer molding apparatus 601, and a fin (not shown) is separated to form terminals. As a result, the power module 300 in which terminals are formed and the sheet-shaped member 440 including the resin insulating layer 441 and the metal foil 442 are formed.

[0040] Fig. 6(g) illustrates processes of disposing the metal-based heat conduction member 450 and applying the adhesive member 460. The metal-based heat conduction member 450 is placed on the sheet-shaped member 440, and heated and pressurized to form an alloy layer at an interface between the metal-based heat conduction member 450 and the metal foil 442, and then the adhesive member 460 is applied. By forming the alloy layer at the interface of the metal foil 442, the thermal contact resistance with the metal-based heat conduction member 450 can be reduced. In the cross-sectional shape of the metal-based heat conduction member 450, a central portion is formed thick, and both ends are formed thin. Both ends of the metal-based heat conduction member 450 are in contact with the adhesive member 460.

[0041] Although the metal-based heat conduction member 450 has been described by taking a sheet member covering the second circuit board 431 and the fourth circuit board 433 as an example, the metal-based heat conduction member may be a member covering both the second circuit board 431 and the fourth circuit board 433. As described above, in this case, the second circuit board 431 and the fourth circuit board 433 are preferably covered with the separate sheet-shaped members 440. That is, in the metal-based heat conduction member 450, a portion in contact with the sheet-shaped member 440 adhering to the second circuit board 431 and a portion in contact with the sheet-shaped member 440 adhering to the fourth circuit board 433 may be provided separately from each other.Even in this case, by plastically deforming these portions of the metal-based heat conduction member 450, a deflection or a step difference generated in the second circuit board 431 and the fourth circuit board 433 can be absorbed and heat dissipation can be improved.

[0042] Fig. 6(h) illustrates a process of intimate contact of the cooling member 340. The cooling member 340 is brought into close contact with the metal-based heat conduction member 450 and the adhesive member 460. At the same time, by heating and pressurizing, the thermal contact resistance between the cooling member 340 and the metal-based heat conduction member 450 is reduced, and the adhesive member 460 is hardened. Thus, the electric circuit body 400 is formed.

[0043] Fig. 7(i) to 7(j) are cross-sectional views illustrating a modification 1 of the method for manufacturing the electric circuit body 400 of the present embodiment. On the left side of each drawing, the cross section along the Fig. 1 shown line XX and on the right side of each drawing is a power module with the cross section along line YY in Fig. 1 shown.

[0044] The same applies to the manufacturing process in variation 1 up to the one described above. Fig. 6(f) is applicable and a description thereof is omitted.

[0045] Fig. 7(i) illustrates a disposition process of the metal-based heat conduction member 450. The metal-based heat conduction member 450 is disposed on the sheet-shaped member 440. In Modification 1, the adhesive member 460 is not used. The metal-based heat conduction member 450 has a cuboid cross section.

[0046] Fig. 7(j) illustrates a process of intimate contact of the cooling member 340. The cooling member 340 is brought into close contact with the metal-based heat conduction member 450. At the same time, heating and pressurization reduce the thermal contact resistance between the cooling member 340 and the metal-based heat conduction member 450. Thus, the electric circuit body 400 is formed.

[0047] Fig. 8(k) to 8(n) are cross-sectional views illustrating Modification 2 of the method for manufacturing the electric circuit body of the present embodiment. On the left side of each drawing, the cross section along the Fig. 1 shown line XX and on the right side of each drawing is a power module with the cross section along the line shown in Fig. 1 shown line YY.

[0048] The same applies to the manufacturing process in variation 2 up to the one described above. Fig. 6(f) is applicable and a description thereof is omitted.

[0049] Fig. 8(k) illustrates a deposition process of the metal-based heat conduction member 450. The molten metal-based heat conduction member 450 is deposited on the sheet-shaped member 440. By depositing the molten metal-based heat conduction member 450, the metal foil 442 and the alloy layer can be formed, and the thermal contact resistance can be reduced. Furthermore, the deposition of the molten metal-based heat conduction member 450 can achieve cost reduction compared to the case where the metal-based heat conduction member is deposited in a sheet-shaped form.

[0050] Fig. 8(I) illustrates a planarization process of the metal-based heat conduction member 450. The deposited metal-based heat conduction member 450 is planarized using a heated deformation chuck 604 in a molten state.

[0051] Fig. 8(m) illustrates a cross-section of the planarized metal-based heat conduction member 450.

[0052] Fig. 8(n) illustrates a process of intimate contact of the cooling member 340. The cooling member 340 is brought into close contact with the metal-based heat conduction member 450. At the same time, heating and pressurization reduce the thermal contact resistance between the cooling member 340 and the metal-based heat conduction member 450. Thus, the electric circuit body 400 is formed.

[0053] Fig. 9 is a semi-transparent top view of the power module 300. Although in Fig. 1 shows three power modules 300, Fig. 9 shows a power module 300 as an example. Fig. 10 is a circuit diagram of a power module 300.

[0054] As in Fig. 9 and Fig. As shown in Figure 10, the upper branch circuit includes a first active element 155 and a first diode 156 of the upper branch circuit. The lower branch circuit includes a second active element 157 and a second diode 158 of the lower branch circuit. The first active element 155 and the second active element 157 are, for example, IGBTs.

[0055] As in Fig. 9 and Fig. As shown in Figure 10, the positive electrode side terminal 315B is led out from the collector side of the upper arm circuit, and the positive electrode side terminal 315B is connected to the positive electrode side of a battery or capacitor. The upper arm gate signal terminal 325U is led out from the gate and emitter sense of the first active element 155 of the upper arm circuit. The negative electrode side terminal 319B is led out from the emitter side of the lower arm circuit, and the negative electrode side terminal 319B is connected to the negative electrode side of the battery or capacitor or to GND. The lower arm gate signal terminal 325L is led out from the gate and emitter sense of the second active element 157 of the lower arm circuit.Terminal 320B on the AC side is led out from the collector side of the lower arm circuit and is connected to a motor. When the neutral point is grounded, the lower arm circuit is not connected to GND, but to the negative electrode side of the capacitor.

[0056] As in Fig. As shown in FIG. 9, terminals such as a Kelvin emitter signal terminal 325K, a lower arm gate signal terminal 325L, a mirror emitter signal terminal 325M, and an upper arm gate signal terminal 325U are provided. Furthermore, a first circuit board 430 is provided on the collector side of the upper arm circuit, a second circuit board 431 is provided on the emitter side of the upper arm circuit, a third circuit board 432 is provided on the collector side of the lower arm circuit, and a fourth circuit board 433 is provided on the emitter side of the lower arm circuit, and these are sealed with the sealing resin 360.

[0057] The power module of the present embodiment has a 2-in-1 structure in which two branch circuits, an upper arm circuit and a lower arm circuit, are integrated into one power module. In addition to the 2-in-1 structure, a 3-in-1 structure in which three branch circuits are integrated into one power module, a 4-in-1 structure in which four branch circuits are integrated into one power module, a 6-in-1 structure in which six branch circuits are integrated into one power module, or the like can be used. When these structures are used, the number of output terminals of the power module can be reduced and downsized.

[0058] Furthermore, in the present embodiment, the structure in which two branch circuits of the upper arm circuit and the lower arm circuit are integrated into one power module has been described, but the present embodiment can be applied to a structure in which the upper arm circuit or the lower arm circuit is integrated into one power module. That is, when the power module includes at least one power semiconductor element, and when the power semiconductor element sandwiched between the printed circuit boards arranged on both surfaces of the power semiconductor element and the cooling member are contacted with each other using the sheet-shaped member 440 and the metal-based heat conduction member 450 described in the present invention, it is possible to absorb the deflection or step difference of the printed circuit board at the contacting surface with the cooling member.This makes it possible to form an electrical circuit body having improved heat dissipation compared to the conventional structure.

[0059] Fig. 11 is a circuit diagram of a power converter 200 using the power module.

[0060] As in Fig. As shown in Figure 11, the power converter 200 includes inverter circuit units 140, 142, an auxiliary inverter circuit unit 43, and a capacitor module 500.

[0061] The inverter circuit units 140 and 142 include a plurality of power modules 300, and by connecting the power modules, a three-phase inverter circuit is configured. Further, when the current carrying capacity is high, the power modules 300 are connected in parallel, and these parallel connections are configured according to the respective phases of the three-phase inverter circuit, making it possible to cope with an increase in the current carrying capacity. In addition, by connecting the active elements 155, 157 and the diodes 156, 158, which are power semiconductor elements incorporated in the power module 300, in parallel, it is also possible to cope with an increase in the current carrying capacity.

[0062] The inverter circuit unit 140 and the inverter circuit unit 142 have the same basic circuit configuration and also have basically the same control method and operation. Since the circuit operation outline of the inverter circuit unit 140 and the like is well known, a detailed description is omitted here.

[0063] The upper-arm circuit includes an upper-arm active element 155 and an upper-arm diode 156 as switching power semiconductor elements, and the lower-arm circuit includes a lower-arm active element 157 and a lower-arm diode 158 as switching power semiconductor elements. The active elements 155 and 157 perform the switching operation in response to a drive signal output from one or the other of the two drive circuits constituting a drive circuit 174, convert DC power supplied from a battery 136 into three-phase AC power, and drive the motor generators 192 and 194.

[0064] The upper-arm active element 155 and the lower-arm active element 157 include a collector electrode, an emitter electrode, and a gate electrode. The upper-arm diode 156 and the lower-arm diode 158 include two electrodes: a cathode electrode and an anode electrode. As shown in Fig. As shown in Figure 3, the cathode electrodes of the diodes 156, 158 are electrically connected to the collector electrodes of the active elements (IGBTs) 155, 157, and the anode electrodes are electrically connected to the emitter electrodes of the active elements 155, 157, respectively. As a result, the current flows in the forward direction from the emitter electrode to the collector electrode of the active element 155 for the upper arm and the active element 157 for the lower arm.

[0065] It should be understood that a metal oxide semiconductor field effect transistor (MOSFET) may be used as the active element, in which case the diode 156 for the upper branch and the diode 158 for the lower branch become unnecessary.

[0066] The positive electrode side terminal 315B and the negative electrode side terminal 319B of both the upper arm and lower arm series circuits are connected to DC terminals 362A and 362B, respectively, for capacitor connection of the capacitor module 500. AC power is generated at the connection portions of the upper arm circuit and the lower arm circuit, and the connection portions of the upper arm circuit and the lower arm circuit in the upper and lower arm series circuits are connected to the AC side terminals 320B of the power modules 300. The AC side terminal 320B of each power module 300 of each phase is connected to the AC output terminal of the power converter 200, and the generated AC power is supplied to a stator winding of the motor generator 192 or 194.

[0067] The control circuit 172 generates a clock signal based on input information from a control device, a sensor (e.g., a current sensor 180), or the like on the vehicle side to control the switching timing of the upper-arm active element 155 and the lower-arm active element 157. The driver circuit 174 generates a drive signal for switching the upper-arm active element 155 and the lower-arm active element 157 based on the clock signal output from the control circuit 172.

[0068] It is to be understood that reference numerals 181, 182 and 188 denote connectors.

[0069] The upper and lower arm series circuits include a temperature sensor (not shown), and the temperature information of the upper and lower arm series circuits is input to the control circuit 172. Voltage information on a positive DC side of the upper and lower arm series circuits is also input to the control circuit 172. Based on this information, the control circuit 172 performs overtemperature detection and overvoltage detection, stops the switching operation of all upper arm active elements 155 and lower arm active elements 157 when overtemperature or overvoltage is detected, and protects the upper and lower arm series circuits from overtemperature or overvoltage.

[0070] Fig. 12 is a perspective exterior view showing an example of the Fig. 11 shown power converter, and Fig. 13 is a cross-sectional view along the line XV-XV of the Fig. 12 shown power converter.

[0071] As in Fig. As shown in Figure 12, the power converter 200 includes a housing 12 configured by a lower housing 11 and an upper housing 10, which is formed in a substantially cuboid shape. The housing 12 accommodates the electrical circuit body 400, the capacitor module 500, and the like therein. The electrical circuit body 400 has a cooling flow path, and from a side surface of the housing 12, a cooling water inlet pipe 13 and a cooling water outlet pipe 14, which communicate with the cooling flow path, protrude. As shown in Fig. As shown in Fig. 12, the lower case 11 has an opening on the upper side (Z direction), and the upper case 10 is attached to the lower case 11 by closing the opening of the lower case 11. The upper case 10 and the lower case 11 are formed of an aluminum alloy or the like, and are sealed and fixed to the outside. The upper case 10 and the lower case 11 may be integrated. Since the case 12 has a simple cuboid shape, attachment to a vehicle or the like is facilitated, and manufacturing is also facilitated.

[0072] As in Fig. 12, a connector 17 is attached to a side surface in the longitudinal direction of the housing 12, and an AC terminal 18 is connected to the connector 17. A connector 21 is provided on a surface from which the cooling water inlet pipe 13 and the cooling water outlet pipe 14 are led out.

[0073] As in Fig. As shown in FIG. 13, the electrical circuit body 400 is housed in the casing 12. The control circuit 172 and the drive circuit 174 are arranged above the electrical circuit body 400, and the capacitor module 500 is housed on the DC terminal side of the electrical circuit body 400. By arranging the capacitor module at the same height as the electrical circuit body 400, the power converter 200 can be made thinner and the degree of freedom in vehicle installation is improved. The terminal 320B on the AC side of the electrical circuit body 400 penetrates the current sensor 180 and is connected to the connector 188.

[0074] According to the present embodiment, the sheet-shaped member 440 including the resin insulating layer 441 with low thermal conductivity follows the deflection or inclination of the second circuit board 431 and the fourth circuit board 433 with a constant thickness and adheres to them even when the second circuit board 431 and the fourth circuit board 433 are deflected or tilted. On the other hand, the metal-based heat conduction member 450 with high thermal conductivity comes into close contact with the cooling member 340 due to the change in its thickness, and heat dissipation is improved.

[0075] According to the embodiment described above, the following operational effects can be obtained.

[0076] (1) The electric circuit body 400 includes a circuit body 310 having a first power semiconductor element (first active element 155) sandwiched between a first circuit board 430 on one surface thereof and a second circuit board 431 on the other surface thereof, a cooling member 340 disposed on both surfaces of the circuit body 310, a sheet-shaped member 440 adhered to at least the second circuit board 431 and having at least one resin insulating layer 441, and a metal-based heat conduction member 450 provided between the sheet-shaped member 440 and the cooling member 340 in such a manner as to be in contact with the sheet-shaped member 440 and the cooling member 340. This makes it possible to improve heat dissipation without using a ceramic substrate.

[0077] (2) In the method for manufacturing the electric circuit body 400, the first power semiconductor element (first active element 155) is sandwiched between the first circuit board 430 on one surface thereof and the second circuit board 431 on the other surface thereof, the second power semiconductor element (second active element 157) is sandwiched between the third circuit board 432 on one surface thereof and the fourth circuit board 433 on the other surface thereof, the sheet-shaped member 440 is adhered to the second circuit board 431 and the fourth circuit board 433 with at least the resin insulating layer 441 to cover at least the second circuit board 431 and the fourth circuit board 433,The metal-based heat conduction member 450 having regions of different thicknesses along the arrangement direction of the first power semiconductor element (the first active element 155) and the second power semiconductor element (the second active element 157) is adhered to the sheet-like member 440, and the cooling member 340 is brought into close contact with the metal-based heat conduction member 450. This makes it possible to improve heat dissipation without using a ceramic substrate. List of reference symbols 10 upper housing 11 lower housing 13 Cooling water inlet pipe 14 Cooling water drain pipe 17, 21, 181, 182, 188 connectors 18 AC power connection 43, 140, 142 Inverter circuit 155 first active element 156 first diode 157 second active element 158 second diode 172 control circuit 174 driver circuit 180 current sensor 192, 194 Motor generator 200 power converters 300 power module 310 circuit body 315B connection on the positive electrode side 319B Connection on the negative electrode side 320B connection on the AC side 325 signal connection 325K Kelvin emitter signal connection 325L Lower branch gate signal connection 325M mirror-emitter signal connector 325U Gate signal connection of the upper branch 340 cooling element 360 potting resin 400 electrical circuit body 430 first circuit board (collector side of the upper branch circuit) 431 second circuit board (emitter side of the upper branch circuit) 432 third circuit board (collector side of the lower branch circuit) 433 fourth circuit board (emitter side of the lower branch circuit) 440 layered link 441 resin insulation layer 442 metal foil 450 Heat conduction element on a metal basis 460 adhesive link 500 capacitor module 601 injection molding device 602 spring 603 buffer layer 604 Deformation clamping device

Claims

[1] Electrical circuit body comprising: a circuit body (310) having a first power semiconductor element (155) sandwiched between a first circuit board (430) on one surface thereof and a second circuit board (431) on the other surface thereof; a cooling member (340) arranged on both surfaces of the circuit body (310); a sheet-shaped member (440) adhered to at least the second circuit board (431) and having at least one resin insulating layer (441); and a metal-based heat conduction member (450) provided between the sheet-shaped member (440) and the cooling member (340) in such a way that it is in contact with the sheet-shaped member (440) and with the cooling member (340); wherein the metal-based heat conduction member (450) has an adhesive member (460) provided on an outer periphery thereof and sealing the outer periphery of the metal-based heat conduction member (450). [2] Electrical circuit body according to claim 1, wherein the circuit body (310) comprises a second power semiconductor element (157); a third circuit board (432); and a fourth circuit board (433), wherein the second power semiconductor element (157) is housed between the third circuit board (432) on one surface thereof and the fourth circuit board (433) on the other surface thereof, and the sheet-like member (440) is adhered to the second circuit board (431) and to the fourth circuit board (433) in such a way that it covers (433) at least the second circuit board (431) and the fourth circuit board. [3] Electrical circuit body according to claim 1, wherein the circuit body (310) comprises a second power semiconductor element (157); a third circuit board (432); and a fourth circuit board (433), wherein the second power semiconductor element (157) is housed between the third circuit board (432) on one surface thereof and the fourth circuit board (433) on the other surface thereof, the sheet-shaped member (440) comprises a first sheet-shaped member adhered to the second circuit board (431); and a second sheet-shaped member adhered to the fourth circuit board (433), and a portion in contact with the first sheet-shaped member and a portion in contact with the second sheet-shaped member are provided separately from each other in the metal-based heat conduction member (450). [4] The electrical circuit body according to any one of claims 1 to 3, wherein the metal-based heat conduction member (450) has a lower yield point than the cooling member (340). [5] The electrical circuit body according to any one of claims 1 to 3, wherein the metal-based heat conduction member (450) has regions of different thicknesses. [6] The electric circuit body according to claim 2 or 3, wherein the metal-based heat conduction member (450) has regions with different thicknesses along an arrangement direction of the first power semiconductor element (155) and the second power semiconductor element (157). [7] The electric circuit body according to any one of claims 1 to 3, wherein the sheet-shaped member (440) comprises the resin insulating layer (441) and a metal foil (442), and wherein the metal foil (442) is in contact with the metal-based heat conduction member (450). [8] The electrical circuit body according to claim 7, wherein the metal foil (442) is metallically bonded to the metal-based heat conduction member (450). [9] Power converter (200) comprising: an electrical circuit body (310) according to one of claims 1 to 3; and an inverter circuit unit (43; 140; 142) configured by combining the electrical circuit body (310), and which converts DC power into AC power. [10] A method of manufacturing an electrical circuit body (310), the method comprising: Receiving a first power semiconductor element (155) between a first circuit board (430) on one surface thereof and a second circuit board (431) on the other surface thereof; Receiving a second power semiconductor element (157) between a third circuit board (432) on one surface thereof and a fourth (433) circuit board on the other surface thereof; Adhering a sheet-shaped member (440) having at least one resin insulating layer (441) to the second circuit board (431) and to the fourth circuit board (433) to cover at least the second circuit board (431) and the fourth circuit board (433); Adhering a metal-based heat conduction member (450) having regions of different thicknesses along an arrangement direction of the first power semiconductor element (155) and the second power semiconductor element (157) to the sheet-like member (440); and Bringing a cooling member (340) into close contact with the metal-based heat conduction member (450), wherein an adhesive member (460) is applied to an outer periphery of the metal-based heat conduction member (450), which adhesive member seals the outer periphery of the metal-based heat conduction member (450). [11] A method for manufacturing an electric circuit body (310) according to claim 10, wherein the sheet-shaped member (440) comprises the resin insulating layer (441) and a metal foil (442), the metal foil (442) being in contact with the metal-based heat conduction member (450). [12] A method of manufacturing an electrical circuit body (310) according to claim 11, wherein the metal foil (442) is metallically bonded to the metal-based heat conduction member (450). [13] A method for manufacturing an electric circuit body (310) according to claim 10, wherein the sheet-shaped members (440) on the second circuit board (431) side and on the fourth circuit board (433) side are integrally formed by transfer molding. [14] A method of manufacturing an electric circuit body (310) according to claim 11, wherein the metal-based heat conduction member (450) is melted and bonded to the metal foil (442), and a surface of the metal-based heat conduction member (450) is planarized and then brought into close contact with the cooling member (340).

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