Circuit board, motor controller and power assembly

Abstract

The invention provides a circuit board, a motor controller and a power assembly. The circuit board comprises a first metal layer, an insulating layer and a second metal layer, the first metal layer, the insulating layer and the second metal layer are sequentially arranged in a stacked mode in the thickness direction of the circuit board, a lead frame, a power device and a heat-conducting medium are embedded in the insulating layer, and the lead frame is arranged on the side, facing the first metal layer, of the power device in the thickness direction of the circuit board. The lead frame is used for conducting the power device and the first metal layer. The heat-conducting medium is arranged on one side, facing the second metal layer, of the power device along the thickness direction of the circuit board, and the heat-conducting medium is used for being in contact with the power device and the second metal layer. According to the circuit board, the heat dissipation capability of the power device is improved by optimizing the internal structure, and reliable work of the power device is ensured.

Description

Technical Field

[0001] The present application relates to the field of electronic technology, and in particular to a circuit board, a motor controller and a powertrain. Background Art

[0002] Power devices primarily utilize power components to achieve electrical energy conversion and circuit control. For example, the motor controller in a powertrain receives DC power from the power battery and converts it to AC power via power components to drive the drive motor. Because power components generate significant heat and are susceptible to damage in high-temperature environments, their heat dissipation capabilities need to be improved to match the trend toward miniaturization and higher power density in power devices. Summary of the Invention

[0003] The present application provides a circuit board, a motor controller, and a powertrain. The circuit board has power devices embedded within it, and the circuit board optimizes its internal structure to enhance the heat dissipation capability of the power devices and ensure reliable operation of the power devices.

[0004] In a first aspect, the present application provides a circuit board. The circuit board includes a first metal layer, an insulating layer, and a second metal layer, wherein the first metal layer, the insulating layer, and the second metal layer are stacked in sequence along the thickness direction of the circuit board. A lead frame, a power device, and a thermal conductive medium are embedded in the insulating layer. The lead frame is arranged along the thickness direction of the circuit board on the side of the power device facing the first metal layer, and the lead frame is used to conduct electricity between the power device and the first metal layer. The thermal conductive medium is arranged along the thickness direction of the circuit board on the side of the power device facing the second metal layer, and the thermal conductive medium is used to contact the power device and the second metal layer, respectively.

[0005] The circuit board provided in this application comprises a lead frame, a power device, and a heat-conducting medium wrapped in an insulating layer. The lead frame is used to connect the power device and the first metal layer from one side, allowing the power device to be connected to the external circuit through the first metal layer. The heat-conducting medium is used to transfer heat from the power device to the second metal layer from the other side, allowing the power device to dissipate heat outward through the second metal layer. The circuit board provided in this application integrates the power device in an embedded manner, resulting in a compact structure that can ensure the heat dissipation capability of the power device.

[0006] In one implementation, the thermal conductive medium is one of ceramic, aluminum nitride (AlN), and silicon nitride (SiN), thereby ensuring a high thermal conductivity of the thermal conductive medium, improving the heat dissipation effect of the power device, and ensuring the insulation of the power device.

[0007] In one implementation, the projection of the heat-conducting medium along the thickness direction of the circuit board covers the projection of the power device.

[0008] In this implementation, the area of ​​the heat-conducting medium along the plane of the circuit board is larger than the area of ​​the power device, so the power device can be completely attached to the heat-conducting medium to ensure heat dissipation effect.

[0009] In one implementation, the second metal layer includes a heat dissipation surface facing away from the insulating layer along the thickness direction of the circuit board. The heat dissipation surface includes a plurality of pins arranged in an array. The projection of the heat-conducting medium along the thickness direction of the circuit board covers the projection of part of the pins.

[0010] In this implementation, the pins can increase the heat dissipation area of ​​the second metal layer and improve the heat dissipation effect of the second metal layer. The area of ​​the pin array along the plane of the circuit board is larger than the area of ​​the thermal conductive medium, which can achieve a better heat dissipation effect on the thermal conductive medium.

[0011] In one implementation, the thickness of the second metal layer along the thickness direction of the circuit board is greater than the thickness of the first metal layer.

[0012] In this implementation, the first metal layer is used to conduct power devices and is relatively thin to reduce the overall thickness of the circuit board. The second metal layer is used to dissipate heat from the power devices and is relatively thick to ensure heat dissipation.

[0013] In one implementation, the insulating layer includes a first sub-insulating layer, the first sub-insulating layer is used to contact the second metal layer, and the thickness of the first sub-insulating layer along the thickness direction of the circuit board is equal to the thickness of the heat-conducting medium.

[0014] In this implementation, the insulation layer is composed of multiple sub-insulation layers stacked sequentially. The first sub-insulation layer and the thermally conductive medium are bonded to the second metal layer. The thickness of the first sub-insulation layer and the thermally conductive medium are equal, facilitating the subsequent stacking of sub-insulation layers and power devices, while ensuring the overall flatness of the circuit board.

[0015] In one implementation, the material of the first sub-insulating layer is prepreg (PP).

[0016] In one implementation, the insulating layer includes a second sub-insulating layer, which is arranged on the side of the first sub-insulating layer away from the second metal layer along the thickness direction of the circuit board. The second sub-insulating layer is in contact with the first sub-insulating layer, and the thickness of the second sub-insulating layer along the thickness direction of the circuit board is equal to the thickness of the power device.

[0017] In this implementation, the second sub-insulating layer is laminated onto the first sub-insulating layer, and the power devices are laminated onto the thermally conductive medium. Because the first sub-insulating layer and the thermally conductive medium are of equal thickness, and the second sub-insulating layer and the power devices are of equal thickness, this facilitates the subsequent lamination of the sub-insulating layers and lead frame, ensuring the overall flatness of the circuit board.

[0018] In one implementation, the second sub-insulating layer is made of epoxy board (FR-4).

[0019] In one implementation, the stiffness of the second sub-insulating layer is greater than that of the first sub-insulating layer, the second sub-insulating layer is spaced from the power device along the plane direction of the circuit board, and the first sub-insulating layer is used to fill the gap between the second sub-insulating layer and the power device.

[0020] In this implementation, because the thickness of the power device is greater than that of the thermally conductive medium, the thickness of the second sub-insulating layer is also correspondingly greater than that of the first sub-insulating layer. Setting the stiffness of the second sub-insulating layer greater than that of the first sub-insulating layer can improve the overall structural stiffness of the circuit board.

[0021] However, because the second sub-insulating layer has greater rigidity, it is necessary to set openings corresponding to the positions of the power devices during the production of the second sub-insulating layer, and flow through the first sub-insulating layer to fill the gap between the second sub-insulating layer and the power device to wrap and fix the power device.

[0022] In one implementation, the lead frame includes an intermediate metal layer and multiple pins. The intermediate metal layer is spaced apart from the first metal layer and the power device along the thickness of the circuit board, and each pin is configured to extend along the thickness of the circuit board. Along the thickness of the circuit board, some of the multiple pins are arranged on the side of the intermediate metal layer facing the power device, while others are arranged on the side of the intermediate metal layer facing the first metal layer. The multiple pins are configured to sequentially connect the power device, the intermediate metal layer, and the first metal layer.

[0023] In this implementation, the power device includes a source, gate, and drain, each of which needs to be electrically connected to an external circuit. The lead frame transmits electrical signals along the plane of the circuit board via an intermediate metal layer. The lead frame also transmits electrical signals through the thickness of the circuit board via multiple pins. Through the interaction of these pins and the intermediate metal layer, the source, gate, and drain of the power device are each electrically connected to the first metal layer.

[0024] In one implementation, the first metal layer and the middle metal layer also implement the transmission function of other electrical signals of the circuit board through patterning.

[0025] In one implementation, the lead frame includes a plurality of intermediate metal layers, which are sequentially spaced apart along the thickness direction of the circuit board, and two adjacent intermediate metal layers are connected via pins.

[0026] In one implementation, the projection of the power device along the thickness direction of the circuit board covers the projections of the plurality of pins.

[0027] In this implementation, the transmission distance between multiple pins and the source, gate and drain of the power device along the planar direction of the circuit board is short, which can shorten the drive circuit and power circuit of the power device, reduce parasitic inductance, and improve the current output capacity and power density of the circuit board.

[0028] In one implementation, the first metal layer includes an outer surface facing away from the insulating layer along the thickness direction of the circuit board, and the outer surface includes multiple welding areas insulated from each other. The multiple welding areas are used to respectively conduct power devices, and the projection of the power device along the thickness direction of the circuit board covers the projections of the multiple welding areas.

[0029] In this implementation, multiple, spaced-apart soldering areas on the outer surface of the first metal layer form a plurality of solder pads, each of which is used to independently conduct current to one of the source, gate, and drain electrodes of a power device. Along the plane of the circuit board, the transmission distances between the multiple solder pads and the multiple pins, as well as the source, gate, and drain electrodes of the power device, are relatively short. This shortens the drive and power circuits of the power device, reduces parasitic inductance, and improves the circuit board's current capacity and power density.

[0030] In one implementation, the circuit board includes a solder resist layer, which is stacked on the side of the first metal layer away from the insulating layer along the thickness direction of the circuit board. The solder resist layer includes multiple hollow areas, each hollow area is used to expose a welding area.

[0031] In this implementation, because the projection of the power device along the thickness of the circuit board overlaps the projections of multiple soldering areas, the soldering areas are closely spaced. The solder mask layer separates and insulates the soldering areas from each other, ensuring reliable conduction between the power device and the external circuit and preventing short circuits.

[0032] In one implementation, a plurality of power devices are embedded in the insulating layer, and the plurality of power devices are arranged at intervals along the plane direction of the circuit board, and the heat conducting medium is used to contact each power device respectively.

[0033] In this implementation, multiple power devices can be integrated inside the circuit board, each power device is connected to the external circuit through a lead frame, and the same thermal conductive medium is used to achieve heat dissipation of each power device.

[0034] In a second aspect, the present application provides a motor controller. The motor controller includes a heat sink and the circuit board provided by any of the implementations of the first aspect. The heat sink is stacked along the thickness of the circuit board on a side of the second metal layer facing away from the insulating layer, with the heat sink's projection along the thickness of the circuit board overlapping the heat-conducting medium's projection.

[0035] The motor controller provided in this application is a power device. The motor controller dissipates heat from the second metal layer through a heat sink, further improving the heat dissipation capacity of the circuit board, ensuring reliable operation of the power device, and facilitating the miniaturization of the power device and improving the power density.

[0036] In one implementation, the heat sink includes a groove, the notch of the groove along the thickness direction of the circuit board faces the second metal layer, the heat sink is used to seal and fit with the second metal layer to enclose and form a water-cooling cavity, and the projection of the groove along the thickness direction of the circuit board covers the projection of the heat-conducting medium.

[0037] In this implementation, the heat sink is provided with a water cooling cavity corresponding to the heat conducting medium to enhance the heat dissipation capability of the power device.

[0038] In one implementation, the second metal layer includes a plurality of pins, and the plurality of pins are used to extend into the water-cooling cavity.

[0039] In one implementation, the power device includes a sealing ring, which is arranged between the circuit board and the heat sink along the thickness direction of the circuit board. The sealing ring is used to surround the periphery of the water cooling cavity along the plane direction of the circuit board to seal the water cooling cavity.

[0040] In a third aspect, the present application provides a powertrain comprising a drive motor and a motor controller provided in any of the implementations of the second aspect. The motor controller is configured to drive the drive motor. The powertrain provided in this application has excellent heat dissipation, a compact size, and high power density. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solution of the present application, the following is a brief introduction to the drawings required for use in the implementation. Obviously, the drawings described below are only some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0042] Figure 1 A schematic diagram of the structure of a motor controller provided in one embodiment of the present application;

[0043] Figure 2 A schematic diagram of the decomposed structure of a motor controller provided in one embodiment of the present application;

[0044] Figure 3 A schematic diagram of the cross-sectional structure of a circuit board provided in one embodiment of the present application;

[0045] Figure 4 A schematic diagram of the cross-sectional structure of a circuit board provided in one embodiment of the present application;

[0046] Figure 5A schematic diagram of the cross-sectional structure of a circuit board provided in one embodiment of the present application;

[0047] Figure 6 A schematic diagram of the cross-sectional structure of a circuit board provided in one embodiment of the present application;

[0048] Figure 7 A schematic diagram of the cross-sectional structure of a circuit board provided in one embodiment of the present application;

[0049] Figure 8 A schematic diagram of the cross-sectional structure of a circuit board provided in one embodiment of the present application;

[0050] Figure 9 A schematic diagram of the cross-sectional structure of a circuit board provided in one embodiment of the present application;

[0051] Figure 10 A schematic diagram of the cross-sectional structure of a circuit board provided in one embodiment of the present application;

[0052] Figure 11 A schematic cross-sectional view of a motor controller according to an embodiment of the present application;

[0053] Figure 12 A schematic cross-sectional view of a motor controller according to an embodiment of the present application;

[0054] Figure 13 A schematic cross-sectional view of a motor controller according to an embodiment of the present application. DETAILED DESCRIPTION

[0055] The following will describe the technical solutions in the embodiments of this application in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making any creative work are within the scope of protection of this application.

[0056] The present application provides a circuit board. The circuit board includes a first metal layer, an insulating layer, and a second metal layer. The first metal layer, the insulating layer, and the second metal layer are stacked in sequence along the thickness direction of the circuit board. A lead frame, a power device, and a heat-conducting medium are embedded in the insulating layer. The lead frame is arranged on the side of the power device facing the first metal layer along the thickness direction of the circuit board, and the lead frame is used to conduct electricity between the power device and the first metal layer. The heat-conducting medium is arranged on the side of the power device facing the second metal layer along the thickness direction of the circuit board, and the heat-conducting medium is used to contact the power device and the second metal layer, respectively. The circuit board provided in the present application integrates the power device in an embedded manner, and the structure of the circuit board is compact and can ensure the heat dissipation capacity of the power device.

[0057] The present application provides a motor controller. The motor controller includes a heat sink and the aforementioned circuit board. The heat sink is stacked along the thickness of the circuit board on the side of the second metal layer facing away from the insulating layer. The heat sink's projection along the thickness of the circuit board overlaps the projection of the thermally conductive medium. The motor controller provided herein dissipates heat from the second metal layer through the heat sink, further enhancing the circuit board's heat dissipation capabilities, ensuring reliable operation of power devices and facilitating increased power density.

[0058] The present application provides a powertrain comprising a drive motor and the aforementioned motor controller. The motor controller is used to drive the drive motor. The motor controller provided herein is used to receive direct current (DC) power from an onboard battery pack and, through power conversion, output three-phase AC power to the drive motor to drive the vehicle. The powertrain provided herein has excellent heat dissipation, a compact size, and high power density.

[0059] In some use scenarios, the circuit board provided by the application can be applied to power devices for realizing power conversion and circuit control. Exemplary, the power device with the circuit board provided by the application can be applied to the low-voltage control power supply of electric vehicles and used as a DC-DC conversion unit. Alternatively, the power device with the circuit board provided by the application can be applied to the field of traditional industrial control, such as the uninterruptible power supply (UPS, Uninterruptible Power Supply) of the data center, the inverter of the photovoltaic power generation equipment, the power supply of the server and other scenes.

[0060] The power devices in the circuit board provided herein may be electronic components with power conversion functions. For example, the power devices may be any one or more of a metal-oxide-semiconductor field-effect transistor (MOSFET), an insulated gate bipolar transistor (IGBT), a diode, silicon carbide, and gallium nitride.

[0061] See Figure 1 and Figure 2 ,in Figure 1 This is a schematic diagram of the structure of a motor controller provided by an embodiment of the present application. Figure 2 A schematic diagram of the decomposed structure of a motor controller provided in one embodiment of the present application.

[0062] The motor controller 200 provided in this application includes a heat sink 210 and a circuit board 100. The circuit board 100 is the circuit board provided simultaneously with this application. The circuit board 100 is integrated with power devices, and the power devices generate a large amount of heat when the circuit board 100 is in operation. The heat sink 210 is used to be stacked with the circuit board 100 along the thickness direction of the circuit board 100. The heat sink 210 is used to contact the heat dissipation structure in the circuit board 100, and the heat sink 210 is used to assist the circuit board 100 in dissipating heat to ensure reliable operation of the power devices.

[0063] The motor controller 200 is used to drive the drive motor in the powertrain provided herein. The motor controller 200 receives DC power from the vehicle's battery pack and converts it through the circuit board 100, thereby outputting three-phase AC power to the drive motor in the powertrain to drive the vehicle.

[0064] Please see Figure 3 ,in Figure 3 A schematic cross-sectional view of a circuit board 100 according to an embodiment of the present application.

[0065] like Figure 3 As shown, the circuit board 100 provided in this application includes a first metal layer 10, an insulating layer 30, and a second metal layer 20. The first metal layer 10, the insulating layer 30, and the second metal layer 20 are stacked sequentially along the thickness of the circuit board. In this embodiment, the insulating layer 30 is made of an adhesive material and is used to bond and secure the first metal layer 10 and the second metal layer 20, while also insulating the first metal layer 10 and the second metal layer 20 from each other.

[0066] The insulating layer 30 is embedded with a lead frame 40, a power device 50, and a thermally conductive medium 60. The lead frame 40 is arranged along the thickness of the circuit board 100 on the side of the power device 50 facing the first metal layer 10. The thermally conductive medium 60 is arranged along the thickness of the circuit board 100 on the side of the power device 50 facing the second metal layer 20. That is, along the thickness of the circuit board 100, the thermally conductive medium 60, the power device 50, and the lead frame 40 are stacked in sequence.

[0067] The lead frame 40 is used to contact the power device 50 and the first metal layer 10 respectively, and the lead frame 40 is used to conduct electricity between the power device 50 and the first metal layer 10. The thermal conductive medium 60 is used to contact the power device 50 and the second metal layer 20 respectively, and the thermal conductive medium 60 is used to thermally connect the power device 50 and the second metal layer 20.

[0068] During operation of the circuit board 100 provided herein, the power device 50 conducts electricity to the external circuit via the first metal layer 10, thereby achieving a power conversion function. The power device 50 generates a large amount of heat, which is then transferred outward through the thermally conductive medium 60 and the second metal layer 20 to achieve a heat dissipation effect.

[0069] Thus, the thermally conductive medium 60 and the second metal layer 20 can be considered as the thermally conductive structure of the power device 50. When the circuit board 100 provided in this application is used in the motor controller 200, the heat dissipation block 210 of the motor controller 200 is located on the side of the second metal layer 20 away from the insulating layer 30. The heat dissipation block 210 is used to contact the second metal layer 20 to assist in heat dissipation of the circuit board 100.

[0070] In one embodiment, the projection of the heat sink 210 along the thickness of the circuit board 100 overlaps the projection of the thermally conductive medium 60. This ensures that the heat sink 210 effectively dissipates heat from the thermally conductive medium 60, thereby effectively controlling the temperature of the power device 50 and preventing damage to the power device 50 due to excessive temperature. Because the power device 50 is embedded within the circuit board 100, the integration of the circuit board 100 of the present application is improved, which facilitates the miniaturization of the motor controller 200 provided by the present application and increases the power density of the motor controller 200.

[0071] In one embodiment, the thermal conductive medium 60 is one of ceramic, aluminum nitride (ALN), and silicon nitride (SIN). The thermal conductivity of the thermal conductive medium 60 is higher than the thermal conductivity of the insulating layer 30. The circuit board 100 provided herein can better conduct the heat generated by the power device 50 to the second metal layer 20 through the thermal conductive medium 60, thereby improving the heat dissipation effect of the power device 50 and ensuring insulation between the power device 50 and the second metal layer 20.

[0072] The circuit board 100 provided in the present application wraps the lead frame 40, the power device 50 and the heat-conducting medium 60 through the insulating layer 30. The lead frame 40 is used to conduct the power device 50 and the first metal layer 10 from one side, so that the power device 50 can be connected to the external circuit through the first metal layer 10. The heat-conducting medium 60 is used to transfer the heat of the power device 50 to the second metal layer 20 from the other side, so that the power device 50 can dissipate heat outward through the second metal layer 20. The circuit board 100 provided in the present application integrates the power device 50 in an embedded manner, and forms a heat dissipation structure with strong thermal conductivity for the power device 50 by integrating the heat-conducting medium 60 and the second metal layer 20. The structure of the circuit board 100 provided in the present application is compact and can ensure the heat dissipation capacity of the power device 50.

[0073] In one embodiment, the projection of the thermal conductive medium 60 along the thickness direction of the circuit board 100 covers the projection of the power device 50. That is, along the plane of the circuit board 100, the area of ​​the thermal conductive medium 60 is larger than the area of ​​the power device 50. Along the thickness direction of the circuit board 100, the surface of the power device 50 facing the second metal layer 20 can be completely in contact with the thermal conductive medium 60, thereby achieving sufficient heat dissipation through the thermal conductive medium 60.

[0074] In one embodiment, the projection of the second metal layer 20 along the thickness direction of the circuit board 100 overlaps the projection of the thermal conductive medium 60. That is, along the plane of the circuit board 100, the area of ​​the thermal conductive medium 60 is smaller than the area of ​​the second metal layer 20. Along the thickness direction of the circuit board 100, the surface of the thermal conductive medium 60 facing the second metal layer 20 can be completely attached to the second metal layer 20, achieving sufficient heat dissipation through the second metal layer 20.

[0075] Please see Figure 4 ,in Figure 4 A schematic cross-sectional view of a circuit board 100 according to an embodiment of the present application.

[0076] like Figure 4 As shown, along the thickness direction of the circuit board 100, the second metal layer 20 includes a heat dissipation surface 21 facing away from the insulating layer 30. The heat dissipation surface 21 includes a plurality of pins 22. The plurality of pins 22 are arranged in an array along the plane of the circuit board 100. The plurality of pins 22 can increase the heat dissipation area of ​​the heat dissipation surface 21 of the second metal layer 20, thereby improving the heat dissipation effect of the second metal layer 20. The array-like arrangement of the plurality of pins 22 facilitates the production of the second metal layer 20 and facilitates controlling the position and coverage of the plurality of pins 22 on the heat dissipation surface 21.

[0077] In one embodiment, the projection of the thermal conductive medium 60 along the thickness of the circuit board 100 partially overlaps the projection of the pins 22. As a result, the area of ​​the array of pins 22 along the plane of the circuit board 100 is larger than the area of ​​the thermal conductive medium 60. The position of the array of pins 22 along the thickness of the circuit board 100 is aligned with the thermal conductive medium 60. This improves the heat dissipation effect of the thermal conductive medium 60 and better controls the temperature of the power device 50.

[0078] In one embodiment, the thickness of the second metal layer 20 along the thickness direction of the circuit board 100 is greater than the thickness of the first metal layer 10. Because the first metal layer 10 is used to conduct the power device 50, the thickness of the first metal layer 10 is relatively thin, which can reduce the overall thickness of the circuit board 100. The second metal layer 20 is used to dissipate heat from the power device 50. The thickness of the second metal layer 20 is relatively thick, which can improve the heat dissipation effect of the power device 50. Exemplarily, the thickness of the first metal layer 10 is 0.4±0.1mm, which can ensure the electrical connection effect of the first metal layer 10. The thickness of the second metal layer 20 is between 1mm-2mm to ensure the heat dissipation effect of the second metal layer 20.

[0079] For the circuit board 100 provided in the present application, the insulating layer 30 may be a structure formed by integral injection molding, or may be obtained by sequentially stacking a plurality of sub-insulating layers.

[0080] Please see Figure 5 ,in Figure 5 A schematic cross-sectional view of a circuit board 100 according to an embodiment of the present application.

[0081] exist Figure 5 In the embodiment shown, the insulating layer 30 is obtained by stacking a plurality of sub-insulating layers in sequence. Each sub-insulating layer can be a sheet or a plate. For example, a semi-cured sheet (Prepreg, PP) and an epoxy board (FR-4). By controlling the thickness and flatness of each sub-insulating layer separately, it is beneficial to control the thickness and flatness of the entire insulating layer 30. On the other hand, different materials of each sub-insulating layer can form different effects. For example, a part of the sub-insulating layer has a greater rigidity and can support the overall structure of the insulating layer 30. The bonding performance of another part of the sub-insulating layer is better, which can avoid the delamination of the insulating layer 30 due to thermal fatigue effects.

[0082] like Figure 5 As shown, the multiple sub-insulating layers of the insulating layer 30 in this embodiment include a first sub-insulating layer 31 and a second sub-insulating layer 32. The first sub-insulating layer 31 and the second sub-insulating layer 32 are stacked sequentially along the thickness direction of the circuit board 100. The first sub-insulating layer 31 is located between the second sub-insulating layer 32 and the second metal layer 20. The first sub-insulating layer 31 is configured to contact the second metal layer 20. Along the thickness direction of the circuit board 100, the thickness of the first sub-insulating layer 31 is equal to the thickness of the thermal conductive medium 60.

[0083] In this embodiment, the insulating layer 30 is composed of a plurality of sequentially stacked sub-insulating layers 30. The first sub-insulating layer 31 is attached to the second metal layer 20 together with the thermal conductive medium 60. The first sub-insulating layer 31 and the thermal conductive medium 60 have the same thickness, which facilitates the subsequent stacking of the sub-insulating layers 30 and the power devices 50, and ensures the overall flatness of the circuit board 100.

[0084] In one embodiment, the second sub-insulating layer 32 is arranged on a side of the first sub-insulating layer 31 facing away from the second metal layer 20 along the thickness direction of the circuit board 100. The second sub-insulating layer 32 is in contact with the first sub-insulating layer 31, and the thickness of the second sub-insulating layer 32 along the thickness direction of the circuit board 100 is equal to the thickness of the power device 50.

[0085] In this embodiment, the second sub-insulating layer 32 is laminated on the first sub-insulating layer 31, and the power device 50 is laminated on the thermal conductive medium 60. Because the first sub-insulating layer 31 and the thermal conductive medium 60 have the same thickness, and the second sub-insulating layer 32 and the power device 50 have the same thickness, the subsequent lamination of the sub-insulating layer 30 and the lead frame 40 is facilitated, while ensuring the overall flatness of the circuit board 100.

[0086] In one embodiment, the rigidity of the second sub-insulating layer 32 is greater than that of the first sub-insulating layer 31. Exemplarily, the material of the second sub-insulating layer 32 is an epoxy board, and the material of the first sub-insulating layer 31 is a prepreg.

[0087] In this embodiment, because the thickness of the power device 50 is greater than that of the thermally conductive medium 60, the thickness of the second sub-insulating layer 32 is correspondingly greater than that of the first sub-insulating layer 31. By setting the stiffness of the second sub-insulating layer 32 to be greater than that of the first sub-insulating layer 31, the second sub-insulating layer 32 can better support the overall structure of the insulating layer 30 and improve the overall structural stability of the circuit board 100.

[0088] In one embodiment, the second sub-insulating layer 32 is spaced from the power device 50 along the planar direction of the circuit board 100, and the first sub-insulating layer 31 is also used to fill the gap between the second sub-insulating layer 32 and the power device 50. Because the second sub-insulating layer 32 has a relatively large rigidity, it is necessary to set an opening in the second sub-insulating layer 32 at a position corresponding to the power device 50 during the production of the second sub-insulating layer 32. If the opening is set too small, the power device 50 will not be able to reliably fit with the thermal conductive medium 60. If the opening area is too large, a gap will be formed between the side wall of the power device 50 and the second sub-insulating layer 32. If the medium in the gap is air, the heat dissipation effect of the side wall of the power device 50 will be affected because the thermal conductivity of air is relatively low.

[0089] In this embodiment, because the first sub-insulating layer 31 has relatively low rigidity, environmental parameters can be controlled during the fabrication process of the first sub-insulating layer 31 to render the first sub-insulating layer 31 liquid or gel-like, i.e., the first sub-insulating layer 31 can be fluid. This allows the first sub-insulating layer 31 to flow into and fill the gap between the second sub-insulating layer 32 and the power device 50, thereby wrapping and securing the power device 50 and improving the heat dissipation effect of the sidewalls of the power device 50.

[0090] In one embodiment, the second sub-insulating layer 32 includes another sub-insulating layer on a side facing away from the first sub-insulating layer 31. The material of the other sub-insulating layer is the same as that of the first sub-insulating layer 31. The other sub-insulating layer is used to fill the gap between the second sub-insulating layer 32 and the power device 50. Alternatively, the other sub-insulating layer is used together with the first sub-insulating layer 31 to fill the gap between the second sub-insulating layer 32 and the power device 50.

[0091] Based on the manufacturing sequence of circuit board 100, another sub-insulating layer is formed after first sub-insulating layer 31 and second sub-insulating layer 32. Another sub-insulating layer is also formed after power device 50 is surface-mounted on thermal conductive medium 60. In this case, the gap between power device 50 and second sub-insulating layer 32 is fixed along the plane of circuit board 100, making it easier to control the flow of another sub-insulating layer into and fill the gap between second sub-insulating layer 32 and power device 50.

[0092] Alternatively, along the plane of the circuit board 100, the second sub-insulating layer 32 is spaced from the power device 50. The insulating layer 30 includes a filler material that fills the gap between the second sub-insulating layer 32 and the power device 50. The filler material is used to wrap and secure the power device 50. The filler material has a lower stiffness than the material of the second sub-insulating layer 32. The filler material is made of the same material as the first sub-insulating layer 31.

[0093] Please see Figure 6 ,in Figure 6 A schematic cross-sectional view of a circuit board 100 according to an embodiment of the present application.

[0094] In one embodiment, the lead frame 40 includes an intermediate metal layer 41 and a plurality of pins 42. The intermediate metal layer 41 is spaced apart from the first metal layer 10 and the power device 50 along the thickness of the circuit board 100, and each pin 42 is configured to extend along the thickness of the circuit board 100. A portion of the plurality of pins 42 is arranged along the thickness of the circuit board 100 on the side of the intermediate metal layer 41 facing the power device 50, thereby providing electrical connection between the power device 50 and the intermediate metal layer 41. Another portion of the plurality of pins 42 is arranged on the side of the intermediate metal layer 41 facing the first metal layer 10, thereby providing electrical connection between the intermediate metal layer 41 and the first metal layer 10. Thus, the plurality of pins 42 are configured to sequentially connect the power device 50, the intermediate metal layer 41, and the first metal layer 10 along the thickness of the circuit board 100, allowing the lead frame 40 to provide electrical connection between the power device 50 and the first metal layer 10 via the intermediate metal layer 41 and the plurality of pins 42.

[0095] The power device 50 includes multiple electrodes, exemplarily including a source 51, a gate 52, and a drain 53. The multiple electrodes of the power device 50 need to be electrically connected to an external circuit to achieve the power conversion function of the power device 50. The lead frame 40 transmits electrical signals along the plane of the circuit board 100 via the intermediate metal layer 41. The lead frame 40 transmits electrical signals along the thickness of the circuit board 100 via multiple pins 42. Through the interaction of the multiple pins 42 and the intermediate metal layer 41, the source 51, gate 52, and drain 53 of the power device 50 are electrically connected to the first metal layer 10.

[0096] It is understandable that the first metal layer 10 and the intermediate metal layer 41 need to be patterned separately to achieve relative insulation between multiple electrodes in the power device 50, that is, the multiple electrodes of the power device 50 independently transmit electrical signals through the lead frame 40 and the first metal layer 10.

[0097] Please see Figure 7 ,in Figure 7 A schematic cross-sectional view of a circuit board 100 according to an embodiment of the present application.

[0098] like Figure 7 As shown, in one embodiment, the lead frame 40 includes a plurality of intermediate metal layers 41 , which are sequentially spaced apart along the thickness direction of the circuit board 100 , and two adjacent intermediate metal layers 41 are connected via pins 42 .

[0099] In one embodiment, along the planar direction of the circuit board 100, the first metal layer 10 and each intermediate metal layer 41 are patterned to further include regions that are not electrically connected to the power device 50. These regions of the first metal layer 10 and each intermediate metal layer 41 that are not electrically connected to the power device 50 can be used to implement other electrical signal transmission functions of the circuit board 100.

[0100] In one embodiment, the projection of the power device 50 along the thickness of the circuit board 100 overlaps the projection of the plurality of pins 42. As a result, along the plane of the circuit board 100, the spacing between the plurality of pins 42 and the source 51, gate 52, and drain 53 of the power device 50 is relatively short, and the transmission distance of the intermediate metal layer 41 is correspondingly shortened. This shortens the drive circuit and power circuit of the power device 50, reducing the parasitic inductance of the power device 50 and improving the current outflow capacity and power density of the circuit board 100.

[0101] In one embodiment, the first metal layer 10 includes an outer surface 11 facing away from the insulating layer 30 along the thickness direction of the circuit board 100. The outer surface 11 includes a plurality of mutually insulated welding areas 111. Each welding area 111 is used to conduct power devices 50 respectively. Figure 6 and Figure 7 In the illustrated embodiment, multiple welding regions 111 are used to respectively conduct electricity to the source 51, gate 52, and drain 53 of the power device 50. It can be understood that the multiple welding regions 111 spaced apart from each other on the outer surface 11 of the first metal layer 10 are used to form multiple bonding pads, each of which is used to individually conduct electricity to one of the source 51, gate 52, and drain 53 of the power device 50. This facilitates external circuits to be connected to the interior of the power device 50 through each welding region 111.

[0102] In one embodiment, the projection of the power device 50 along the thickness direction of the circuit board 100 overlaps the projection of the multiple soldering areas 111. As a result, along the plane of the circuit board 100, the spacing between the multiple soldering areas 111 and the source 51, gate 52, and drain 53 of the power device 50 is relatively short, and the transmission distance of the intermediate metal layer 41 is correspondingly shortened. This shortens the drive circuit and power circuit of the power device 50, reducing the parasitic inductance of the power device 50 and improving the current outflow capacity and power density of the circuit board 100.

[0103] In combination with the above-mentioned embodiment in which the projection of the power device 50 along the thickness direction of the circuit board 100 covers the projection of multiple pins 42, the transmission distances between the multiple welding areas 111 and the multiple pins 42, as well as the source 51, gate 52 and drain 53 of the power device 50 along the plane direction of the circuit board 100 are respectively shorter, and the transmission distance of the intermediate metal layer 41 is shortened respectively. The overall drive circuit and power circuit from the power device 50 to the first metal layer 10 are shortened, further reducing the parasitic inductance of the power device 50 and improving the outflow capacity and power density of the circuit board 100.

[0104] Please see Figure 8 ,in Figure 8 A schematic cross-sectional view of a circuit board 100 according to an embodiment of the present application.

[0105] like Figure 8 As shown, in one embodiment, the circuit board 100 includes a solder resist layer 70, which is stacked on the side of the first metal layer 10 away from the insulating layer 30 along the thickness direction of the circuit board 100, and the solder resist layer 70 includes a plurality of hollow areas 71, each hollow area 71 is used to expose a welding area 111.

[0106] In some embodiments, the spacing between the soldering areas 111 along the thickness of the circuit board 100 is relatively close. When the power device 50 is electrically connected to the external circuit via the soldering areas 111, adjacent soldering areas 111 that are relatively close may short-circuit. Using the solder resist layer 70 to separate and insulate the soldering areas 111 from each other ensures reliable electrical connection between the power device 50 and the external circuit and prevents short circuits.

[0107] Please see Figure 9 ,in Figure 9 A schematic cross-sectional view of a circuit board 100 according to an embodiment of the present application.

[0108] like Figure 9 As shown, in one embodiment, a plurality of power devices 50 are embedded in the insulating layer 30. The plurality of power devices 50 are arranged at intervals along the plane direction of the circuit board 100, and the heat conducting medium 60 is used to contact each power device 50 respectively.

[0109] In some usage scenarios, power devices typically require multiple power devices 50 to work together to achieve power conversion. For example, when the motor controller 200 is used in the drive motor controller of an electric vehicle, the motor controller 200 requires three or six power devices 50 to achieve the three-phase AC output function. Therefore, the circuit board 100 can integrate multiple power devices 50 based on the actual application scenario. Each power device 50 is connected to the external circuit through the lead frame 40. In some embodiments, the power device may include multiple circuit boards 100, each circuit board 100 is used to accommodate a power device 50. The power device can also achieve the function of power conversion by controlling the coordination of the various circuit boards 100.

[0110] Among them, Figure 9 In the illustrated embodiment, each power device 50 is provided with a corresponding lead frame 40 and a thermal conductive medium 60. Each lead frame 40 can be used to conduct heat between a power device 50 and the first metal layer 10, and each thermal conductive medium 60 can be used to conduct heat between a power device 50 and the second metal layer 20.

[0111] In one embodiment, the circuit board 100 of the present application may include a lead frame 40, which is used to conduct electricity between each power device 50 and the first metal layer 10. Alternatively, in one embodiment, the circuit board 100 may further include a thermal conductive medium 60, which is used to contact each power device 50 and the second metal layer 20, thereby achieving heat dissipation for each power device 50.

[0112] Please see Figure 10 ,in Figure 10 A schematic cross-sectional view of a circuit board 100 according to an embodiment of the present application.

[0113] exist Figure 10 In the schematic diagram, the same lead frame 40 is used to conduct multiple power devices 50 and the first metal layer 10. The same thermal conductive medium 60 is used to contact each power device 50 and the second metal layer 20 respectively. Figure 10 In the schematic diagram, the same lead frame 40 is used to conduct the source 51, gate 52 and drain 53 of multiple power devices 50 separately, so the same lead frame 40 is used in Figure 10 In FIG, it is shown as a state of being broken along the plane direction of the circuit board 100. Figure 10 In addition to the cross section shown, the lead frame 40 includes a connection structure to connect the disconnected parts into one, thereby forming an effect that the same lead frame 40 is used to conduct multiple power devices 50 and the first metal layer 10 .

[0114] In one embodiment, the projection of the heat-conducting medium 60 along the thickness direction of the circuit board 100 covers each power device 50 , so as to ensure the heat dissipation effect of the same heat-conducting medium 60 on each power device 50 .

[0115] Please see Figure 11 ,in Figure 11 A schematic cross-sectional structure diagram of a motor controller 200 provided in one embodiment of the present application.

[0116] The heat sink 210 in the motor controller 200 provided herein assists in dissipating heat from the circuit board 100 by attaching to the second metal layer 20 of the circuit board 100. Specifically, along the thickness of the circuit board 100, the heat sink 210 includes a first surface 211 and a second surface 212 that face each other. The first surface 211 is in contact with the second metal layer 20, while the second surface 212 faces away from the circuit board 100.

[0117] In one embodiment, the second surface 212 includes a plurality of heat dissipation fins 2121. The plurality of heat dissipation fins 2121 are arranged at intervals along the plane of the circuit board 100, and each heat dissipation fin 2121 is configured to extend along the thickness direction of the circuit board 100 in a direction away from the first surface 211. The plurality of heat dissipation fins 2121 is configured to increase the heat dissipation area of ​​the heat dissipation block 210 and enhance the heat dissipation effect of the heat dissipation block 210.

[0118] In one embodiment, the projections of the plurality of heat dissipating fins 2121 along the thickness direction of the circuit board 100 at least partially cover the projections of the thermal conductive medium 60. As a result, the areas where the plurality of heat dissipating fins 2121 are located along the plane of the circuit board 100 are at least partially aligned with the thermal conductive medium 60. The plurality of heat dissipating fins 2121 provide a better heat dissipation effect on the power device 50.

[0119] In one embodiment, the heat sink 210 includes a groove 213. The groove 213 faces the second metal layer 20 along the thickness direction of the circuit board 100. The heat sink 210 is used to seal and fit with the second metal layer 20 to form a water cooling cavity.

[0120] Please see Figure 12 ,in Figure 12 A schematic cross-sectional structure diagram of a motor controller 200 provided in one embodiment of the present application.

[0121] like Figure 12As shown, the groove 213 of the heat sink block 210 is located on the first surface 211. The notch of the groove 213 faces the second metal layer 20. Because the first surface 211 is in contact with the second metal layer 20, the second metal layer 20 is able to shield the notch of the groove 213. The heat sink block 210 is used to seal and fit with the second metal layer 20 to enclose the groove 213 to form a water-cooling cavity. The heat sink block 210 may include an internal flow channel (not shown in the figure), which is used to connect the groove 213 and realize the circulation of the refrigerant in the water-cooling cavity by connecting with the external cooling pipeline. In this way, the heat sink block 210 is able to form a circulating heat dissipation effect on the circuit board 100, thereby improving the heat dissipation capacity of the circuit board 100 and ensuring the reliable operation of the motor controller 200.

[0122] In one embodiment, the projection of the groove 213 along the thickness of the circuit board 100 overlaps the projection of the thermal conductive medium 60. That is, the groove 213 is aligned with the thermal conductive medium 60 along the thickness of the circuit board 100. The heat sink 210 further enhances the heat dissipation capability of the motor controller 200 by providing a water cooling cavity corresponding to the location of the thermal conductive medium 60.

[0123] This corresponds to the embodiment in which the circuit board 100 includes multiple power devices 50. When a thermally conductive medium 60 is used to dissipate heat for multiple power devices 50, the heat dissipation block 210 may include a groove 213. By aligning a groove 213 with a thermally conductive medium 60 along the thickness direction of the circuit board 100, the multiple power devices 50 can be dissipated heat simultaneously. When the circuit board 100 includes multiple thermally conductive media 60, each thermally conductive medium 60 is used to dissipate heat for a power device 50, the heat dissipation block 210 may include multiple grooves 213, each groove 213 is used to align with a thermally conductive medium 60 along the thickness direction of the circuit board 100, and mainly dissipate heat for the power device 50 attached to the thermally conductive medium 60.

[0124] In one embodiment, the second metal layer 20 includes a plurality of pins 22 , which are used to extend into the water-cooling cavity to increase the heat exchange area between the second metal layer 20 and the refrigerant in the water-cooling cavity, thereby improving the heat dissipation effect of the motor controller 200 .

[0125] Correspondingly, when the circuit board 100 includes multiple power devices 50 and a thermally conductive medium 60, the multiple pins 22 are arranged to form a pin array and housed within the same recess 213. Alternatively, when the circuit board 100 includes multiple power devices 50 and multiple thermally conductive mediums 60, the multiple pins 22 are arranged to form multiple pin arrays, each of which is housed within a recess 213. Along the plane of the circuit board 100, the spacing between two adjacent pin arrays is greater than the spacing between two recesses 213.

[0126] Please see Figure 13 ,in Figure 13 A schematic cross-sectional structure diagram of a motor controller 200 provided in one embodiment of the present application.

[0127] like Figure 13 As shown, in one embodiment, the motor controller 200 includes a sealing ring 220. The sealing ring 220 is arranged between the circuit board 100 and the heat sink 210 along the thickness direction of the circuit board 100. The sealing ring 220 is used to surround the periphery of the water-cooling chamber along the plane direction of the circuit board 100 to seal the water-cooling chamber. Specifically, the first surface 211 of the heat sink 210 includes an annular receiving groove 2111. Along the thickness direction of the circuit board 100, the notch of the annular receiving groove 2111 faces the circuit board 100. Along the plane direction of the circuit board 100, the annular receiving groove 2111 surrounds the outside of the notch of the groove 213. The annular receiving groove 2111 is used to accommodate and fix the sealing ring 220. Along the thickness direction of the circuit board 100, the groove depth of the annular receiving groove 2111 is less than the thickness of the sealing ring 220 in its natural state. When the heat sink 210 is attached to the circuit board 100 , the second metal layer 20 of the circuit board 100 is used to squeeze the sealing ring 220 to achieve a sealed fit between the circuit board 100 and the heat sink 210 , thereby ensuring the sealing of the water cooling chamber.

[0128] It is understandable that, corresponding to the embodiment in which the second metal layer 20 includes multiple pin arrays, space for accommodating the sealing ring 220 needs to be reserved between two adjacent pin arrays to ensure reliable contact between the second metal layer 20 and the sealing ring 220.

[0129] Obviously, those skilled in the art may make various modifications and variations to this application without departing from the scope of protection of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A circuit board, characterized in that: The circuit board comprises a first metal layer, an insulating layer and a second metal layer, wherein the first metal layer, the insulating layer and the second metal layer are stacked in sequence along the thickness direction of the circuit board, and a lead frame, a power device and a heat conducting medium are embedded in the insulating layer, wherein: The lead frame is arranged along the thickness direction of the circuit board on the side of the power device facing the first metal layer, and the lead frame is used to conduct the power device and the first metal layer; The heat-conducting medium is arranged on a side of the power device facing the second metal layer along the thickness direction of the circuit board, and the heat-conducting medium is used to contact the power device and the second metal layer respectively.

2. The circuit board according to claim 1, characterized in that The projection of the heat-conducting medium along the thickness direction of the circuit board covers the projection of the power device.

3. The circuit board according to claim 1 or 2, characterized in that: The second metal layer includes a heat dissipation surface facing away from the insulating layer along the thickness direction of the circuit board, and the heat dissipation surface includes a plurality of pins arranged in an array. The projection of the heat-conducting medium along the thickness direction of the circuit board covers part of the projection of the pins.

4. The circuit board according to any one of claims 1 to 3, characterized in that: The thickness of the second metal layer along the thickness direction of the circuit board is greater than the thickness of the first metal layer.

5. The circuit board according to any one of claims 1 to 4, characterized in that: The insulating layer includes a first sub-insulating layer, the first sub-insulating layer is used to contact the second metal layer, and the thickness of the first sub-insulating layer along the thickness direction of the circuit board is equal to the thickness of the heat-conducting medium.

6. The circuit board according to claim 5, characterized in that: The insulating layer includes a second sub-insulating layer, which is arranged on the side of the first sub-insulating layer away from the second metal layer along the thickness direction of the circuit board. The second sub-insulating layer is in contact with the first sub-insulating layer, and the thickness of the second sub-insulating layer along the thickness direction of the circuit board is equal to the thickness of the power device.

7. The circuit board according to claim 6, characterized in that: The second sub-insulating layer has a stiffness greater than that of the first sub-insulating layer. The second sub-insulating layer is spaced apart from the power device along the plane direction of the circuit board. The first sub-insulating layer is used to fill a gap between the second sub-insulating layer and the power device.

8. The circuit board according to any one of claims 1 to 7, characterized in that: The lead frame includes an intermediate metal layer and a plurality of pins, wherein the intermediate metal layer is spaced apart from the first metal layer and the power device respectively along the thickness direction of the circuit board, and each of the pins is used to extend along the thickness direction of the circuit board, wherein: Along the thickness direction of the circuit board, a portion of the multiple pins are arranged on the side of the intermediate metal layer facing the power device, and another portion of the pins are arranged on the side of the intermediate metal layer facing the first metal layer. The multiple pins are used to sequentially conduct the power device, the intermediate metal layer and the first metal layer.

9. The circuit board according to claim 8, characterized in that: The lead frame includes a plurality of intermediate metal layers, which are arranged in sequence and spaced apart along the thickness direction of the circuit board, and two adjacent intermediate metal layers are connected through the pins.

10. The circuit board according to claim 8 or 9, characterized in that: The projection of the power device along the thickness direction of the circuit board covers the projections of the plurality of pins.

11. The circuit board according to any one of claims 1 to 10, characterized in that: The first metal layer includes an outer surface facing away from the insulating layer along the thickness direction of the circuit board, and the outer surface includes a plurality of welding areas insulated from each other. The plurality of welding areas are used to respectively conduct the power devices, and the projection of the power device along the thickness direction of the circuit board covers the projection of the plurality of welding areas.

12. The circuit board according to claim 11, characterized in that: The circuit board includes a solder resist layer, which is stacked and arranged on a side of the first metal layer away from the insulating layer along the thickness direction of the circuit board. The solder resist layer includes a plurality of hollow areas, each of which is used to expose one of the welding areas.

13. The circuit board according to any one of claims 1 to 12, characterized in that: A plurality of the power devices are embedded in the insulating layer. The plurality of the power devices are arranged at intervals along the plane direction of the circuit board. The heat-conducting medium is used to contact each of the power devices respectively.

14. A motor controller, characterized in that: The motor controller includes a heat sink and a circuit board as described in any one of claims 1 to 13, wherein the heat sink is used to be stacked along the thickness direction of the circuit board on the side of the second metal layer away from the insulating layer, and the projection of the heat sink along the thickness direction of the circuit board covers the projection of the heat conducting medium.

15. The motor controller according to claim 14, characterized in that: The heat sink block includes a groove, and the notch of the groove faces the second metal layer along the thickness direction of the circuit board. The heat sink block is used to seal and fit with the second metal layer to enclose and form a water-cooling cavity. The projection of the groove along the thickness direction of the circuit board covers the projection of the heat-conducting medium.

16. A powertrain, characterized in that: The powertrain includes a drive motor and a motor controller as claimed in claim 14 or 15, and the motor controller is used to drive the drive motor.

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