Power module having enhanced heat dissipation and power conversion device

Abstract

The present application relates to the technical field of power electronics, and discloses a power module having enhanced heat dissipation and a power conversion device. The power module comprises a substrate, a chip, a package and a heat sink. The substrate comprises a first surface and a second surface opposite to each other, and the chip and the first surface of the substrate are both arranged in the package. The heat sink is located on the side of the second surface facing away from the first surface. The second surface of the substrate comprises a first soldering surface, the surface of the side of the heat sink facing the substrate comprises protrusions, and the surface of each protrusion comprises a second soldering surface. The first soldering surface and the second soldering surfaces have the same bending direction, the first soldering surface and the second soldering surfaces are arranged opposite to each other, and the first soldering surface and the second soldering surfaces are soldered by means of a solder layer. By means of the arrangements provided in the present application, the soldering reliability between the first soldering surface and the second soldering surfaces can be improved, improving the heat conduction efficiency between the substrate and the heat sink, thereby improving the heat dissipation efficiency of the power module, and thus increasing the power density of the power conversion device.

Description

A power module and power conversion device with enhanced heat dissipation

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411985726.5, filed on December 30, 2024, entitled "A Power Module and Power Conversion Device with Enhanced Heat Dissipation", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of power electronics technology, and in particular to a power module and power conversion device with enhanced heat dissipation. Background Technology

[0004] A power module is a functional module that combines power electronic devices according to certain functions and then encapsulates or pots them into a whole. It is widely used in various power conversion equipment. Taking the vehicle motor control unit (MCU) as an example, the vehicle MCU can be used to convert the DC power from the power battery into AC power to supply the motor, thereby providing power to the electric vehicle to make the electric vehicle run.

[0005] As power modules increase their power processing capabilities, the power density output of power modules in automotive MCUs and other power conversion devices is becoming increasingly higher, resulting in greater heat generation. Therefore, to ensure the safe and efficient operation of power conversion equipment, it is necessary to dissipate the heat generated by the power modules in a timely manner, which places higher demands on the heat dissipation of power modules. Summary of the Invention

[0006] This application provides a power module and power conversion device with enhanced heat dissipation, which improves the heat dissipation efficiency of the power module and thus helps to increase the power density of the power conversion device.

[0007] In a first aspect, this application provides a power module with enhanced heat dissipation. The power module includes a substrate, a chip, a package, and a heat sink. The substrate includes a first surface and a second surface disposed opposite to each other. Both the chip and the first surface of the substrate are disposed within the package. The heat sink is located on the side of the second surface opposite to the first surface. The second surface of the substrate includes a first welding surface, and the surface of the heat sink facing the substrate includes a protrusion, the surface of which includes a second welding surface. In this application, the first welding surface and the second welding surface have the same bending direction, are disposed opposite to each other, and are welded together by a solder layer. Using the configuration of the power module provided in this application can improve the uniformity of the solder layer thickness between the first welding surface and the second welding surface, thereby improving the welding reliability of the first welding surface and the second welding surface. This improves the heat conduction efficiency between the substrate and the heat sink, thus enhancing the heat dissipation efficiency of the power module.

[0008] In one possible implementation of this application, along the direction from the first surface to the second surface, the projection of the first welding surface covers the projection of the second welding surface, and the projected area of ​​the first welding surface is larger than the projected area of ​​the second welding surface. This can help improve the connection reliability between the solder layer and the first and second welding surfaces.

[0009] Furthermore, the angle between the portion of the second surface located around the first welding surface and the outer surface of the solder layer is a right angle or an obtuse angle. This helps to reduce the stress in the solder layer, thereby improving the welding reliability of the first and second welding surfaces.

[0010] This application does not limit the bending direction of the first welding surface and the second welding surface; it can be set according to specific design requirements.

[0011] For example, in one possible implementation, the first welding surface is a convex surface that bends along the direction from the first surface to the second surface, and the second welding surface is a concave surface that bends along the direction from the first surface to the second surface. In this way, both the first welding surface and the second welding surface are bent along the direction from the first surface to the second surface to improve the welding reliability between the substrate and the heat sink, thereby improving the heat conduction efficiency from the substrate to the heat sink.

[0012] In another possible implementation, the first welding surface is a convex surface curved along the direction from the first surface to the second surface, and the second welding surface is a concave surface curved along the same direction. Alternatively, both the first and second welding surfaces can be planar. Both approaches improve the welding reliability between the substrate and the heat sink, thereby increasing the heat transfer efficiency from the substrate to the heat sink.

[0013] In one possible implementation of this application, the heat sink includes an overflow groove that is recessed along the direction from the first surface to the second surface and is disposed around the protrusion. In this application, the overflow groove can be used to collect solder that overflows during the soldering heating process, thereby ensuring a sufficiently large insulation distance between the pins used to bring out the electrical interface of the chip and the heat sink, thereby improving the operational safety of the power module.

[0014] In one possible implementation of this application, the projection of the substrate onto the surface of the heat sink along the direction from the first surface to the second surface covers the overflow channel. This ensures that solder overflowing during the soldering heating process can flow into the overflow channel.

[0015] In one possible implementation of this application, the substrate-facing surface of the heat sink includes a solder resist layer disposed around a protrusion. The reflow temperature of the solder resist layer is higher than that of the solder layer. This prevents the solder resist layer from melting during the heating and melting of the solder, thereby allowing the solder resist layer to control the deposition of overflowing solder, which helps improve the operational reliability of the power module.

[0016] Furthermore, in this application, the thickness of the solder resist layer is less than the thickness of the protrusion along the direction from the first surface to the second surface. This ensures that the solder resist layer can effectively prevent soldering while also guaranteeing a reliable bond between the second welding surface of the protrusion and the solder.

[0017] In one possible implementation of this application, the chip is located on the first side of the substrate and is electrically connected to the substrate. This helps to shorten the heat conduction path from the chip to the heat sink, thereby improving the heat dissipation efficiency of the power module.

[0018] In another possible implementation of this application, the power module may further include a metal-clad insulating plate connected to a second side of the substrate. The chip is located on the side of the metal-clad insulating plate opposite to the substrate, and the chip is electrically connected to the metal-clad insulating plate. This facilitates an increase in the design size of the first welding surface, thereby improving the heat exchange efficiency between the first and second welding surfaces, and further improving the efficiency of heat transfer from the substrate to the base plate to the heat sink.

[0019] Secondly, this application also provides a power conversion device, which includes a circuit board and a power module as described in the first aspect, wherein the power module is electrically connected to the circuit board. In this power conversion device, since the power module has better heat dissipation performance, it is beneficial to improve the power density of the power conversion device, thereby improving the power conversion performance of the power conversion device. Attached Figure Description

[0020] Figure 1 is a schematic diagram of an application scenario of a new energy vehicle provided in an embodiment of this application;

[0021] Figure 2 is a schematic diagram of a power conversion device provided in an embodiment of this application;

[0022] Figure 3 is a schematic diagram of the state of the welded surface of the power module during the welding process when using traditional welding technology;

[0023] Figure 4 is a schematic diagram of a power module provided in an embodiment of this application;

[0024] Figure 5 is a schematic diagram of the packaging structure and the structure before heat sink welding provided in the embodiment of this application;

[0025] Figure 6 is a schematic diagram of another structure of the power module provided in an embodiment of this application;

[0026] Figure 7 is a schematic diagram of another structure of the power module provided in an embodiment of this application;

[0027] Figure 8 is a schematic diagram of another structure of the power module provided in an embodiment of this application;

[0028] Figure 9 is a schematic diagram of another structure of the power module provided in an embodiment of this application;

[0029] Figure 10 is a schematic diagram of another structure of the power module provided in the embodiment of this application;

[0030] Figure 11a is a partial schematic diagram of one structure of the packaging structure of the power module provided in an embodiment of this application;

[0031] Figure 11b is a partial schematic diagram of another structure of the power module packaging structure provided in the embodiment of this application;

[0032] Figure 12 is a schematic diagram of another structure of the power module provided in the embodiment of this application.

[0033] Reference numerals: 1000-Vehicle power supply; 2000-Powertrain; 3000-Wheel; 100-Power battery; 101-Vehicle charger; 200-Vehicle MCU; 201-Motor; 10-Power module; 1001-Central area; 20-Housing; 30-Circuit board; 40-Heat sink; 41-Protrusion; 411-Second soldering surface; 42-Overflow groove; 43-Solder resist layer; 1-Packaging structure; 11-First soldering surface; 12-Substrate; 121-Ceramic substrate; 122-First metal layer; 123-Second metal layer; 124-First side; 125-Second side; 13-Chip; 14-Metal-clad insulating plate; 2-Solder layer; 3-Pin; 4-Bonding wire. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings. However, the exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein. The same reference numerals in the figures denote the same or similar structures, and therefore repeated descriptions of them will be omitted. The terms expressing position and direction described in the embodiments of this application are illustrative based on the accompanying drawings, but changes can be made as needed, and all such changes are included within the scope of protection of this application. The accompanying drawings of the embodiments of this application are only for illustrating relative positional relationships and do not represent actual scale.

[0035] It should be noted that specific details are set forth in the following description to facilitate understanding of this application. However, the embodiments of this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the embodiments of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0036] Power conversion equipment is widely used in photovoltaic power generation systems, energy storage systems, and powertrain systems of new energy vehicles to convert current or voltage in these systems. Power conversion equipment can include inverters and microinverters in photovoltaic power generation systems, converters in energy storage systems, on-board power supplies and motor control units (MCUs) in the powertrains of new energy vehicles, or blade power supplies at power stations, etc.

[0037] Taking new energy vehicles as an example, Figure 1 is a schematic diagram of an application scenario of a new energy vehicle provided in an embodiment of this application. As shown in Figure 1, the new energy vehicle provided in this embodiment includes an on-board power supply 1000, a powertrain 2000, and wheels 3000. The powertrain 2000 is used to receive electrical energy provided by the on-board power supply 1000 and drive the wheels 3000 to rotate. In this embodiment, the new energy vehicle includes an electric vehicle or a hybrid electric vehicle.

[0038] The vehicle power supply 1000 mainly includes a power battery 100 and an on-board charger (OBC) 101. The on-board OBC 101 is used to convert AC power into high-voltage DC power to supply the power battery 100.

[0039] The powertrain 2000 includes an onboard MCU 200 and a motor 201. The onboard MCU 200 drives the motor 201. Specifically, the onboard MCU 200 receives DC power from the power battery 100 and outputs AC power to the motor 201. The motor 201 receives power from the onboard MCU 200 and drives the wheels 3000 to rotate.

[0040] In this application, the power conversion devices such as the vehicle-mounted OBC 101 and the vehicle-mounted MCU 200 both include power modules. Referring to Figure 2, which is a structural schematic diagram of a power conversion device provided in an embodiment of this application, the power conversion device also includes a housing 20, a circuit board 30, and a heat sink 40. The power module 10, the circuit board 30, and the heat sink 40 are housed within the housing 20, and the power module 10 is electrically connected to the circuit board 30. The circuit board 30 can be a printed circuit board (PCB), a flexible printed circuit board (FPC), or a rigid-flex circuit board, etc. The power module 10 is the core component of the power conversion device that realizes the power conversion function. The power module 10 can include multiple ports, such as input positive and negative ports, output positive and negative ports, power supply positive and negative ports, etc. These ports are electrically connected to the circuit board 30 through pins, thereby utilizing the circuit board 30 to provide current or voltage input and output, as well as power supply functions, to the power module 10.

[0041] The power module 10 may include various power devices such as chips, inductors, resistors, or capacitors. These power devices are connected in a certain functional combination and then packaged into a whole through packaging technology. With the rapid development of power conversion devices such as automotive OBC 101 and automotive MCU 200, the power density of the power module 10 in the power conversion device is getting bigger and bigger. In order to ensure the reliable operation of the power module 10, it is necessary to dissipate the heat generated by the power module 10 in a timely manner.

[0042] Currently, to achieve heat dissipation for the power module 10, thermal grease is typically applied between the heat dissipation surface of the power module 10 and the heat sink 40. This allows the heat generated by the power module 10 to be transferred to the heat sink 40 through the thermal grease, thus achieving heat dissipation for the power module 10. However, since the thermal conductivity of thermal grease is generally between 3-5 W / mK, it is difficult to meet the heat dissipation requirements of the high-power-density power module 10. Solder, on the other hand, typically has a thermal conductivity of 50 W / mK, which is an order of magnitude higher than that of thermal grease. Therefore, using solder will significantly improve the heat transfer efficiency between the power module 10 and the heat sink 40, thereby improving the heat dissipation efficiency of the power module 10.

[0043] However, using traditional welding processes, during the welding process between the power module 10 and the heat sink 40, as shown in Figure 3 (a schematic diagram of the welding surface state during the welding process), the welding surface of the power module 10 warps. This can lead to the formation of a void between the power module 10's central region 1001 and the heat sink 40, as shown in Figure 2, after welding. This void blocks the heat conduction path, affecting the heat dissipation efficiency of the power module 10 and potentially causing it to fail.

[0044] In view of this, the power module provided in this application adopts a contoured surface design to improve the welding reliability between the welding surfaces that are welded to the heat sink, thereby improving the heat dissipation efficiency of the power module. This provides the possibility for further increasing the power density of the power module, which in turn is beneficial to improving the power density of the power conversion equipment. To facilitate understanding of the solution provided in this application, it will be described in detail below with reference to specific embodiments.

[0045] Figure 4 is a schematic diagram of a power module provided in an embodiment of this application. As shown in Figure 4, the power module includes a package structure 1 and a heat sink 40. The side of the package structure 1 facing the heat sink 40 includes a first welding surface 11. The surface of the heat sink 40 facing the package structure 1 includes a protrusion 41. The surface of the protrusion 41 includes a second welding surface 411. The first welding surface 11 and the second welding surface 411 are arranged opposite to each other, and the bending directions of the first welding surface 11 and the second welding surface 411 are the same.

[0046] It is worth mentioning that, in this application, the fact that the first welding surface 11 and the second welding surface 411 have the same bending direction can be understood as follows: when the first welding surface 11 is convex, the second welding surface 411 is concave; and when the first welding surface 11 is concave, the second welding surface 411 is convex. In addition, when the first welding surface 11 is planar, the second welding surface 411 is also planar.

[0047] Referring to Figure 4, the power module also includes a solder layer 2, which is located between the first welding surface 11 and the second welding surface 411, and the first welding surface 11 and the second welding surface 411 are welded together through the solder layer 2.

[0048] As can be seen from Figure 4, by adopting the design scheme provided in this application, since the bending directions of the first welding surface 11 of the package structure 1 and the second welding surface 411 of the heat sink 40 are the same, it is beneficial to improve the uniformity of the thickness of the solder layer 2 located between the first welding surface 11 and the second welding surface 411, thereby improving the welding reliability of the first welding surface 11 and the second welding surface 411. It is also beneficial to improve the heat conduction efficiency between the package structure 1 and the heat sink 40, thereby improving the heat dissipation efficiency of the power module.

[0049] Referring to FIG4, in this application, along the direction from the package structure 1 to the heat sink 40, i.e., the Y direction shown in FIG4, the projection of the first solder surface 11 covers the projection of the second solder surface 411, and the projected area of ​​the first solder surface 11 is larger than the projected area of ​​the second solder surface 411. This allows the cross-section of the solder layer 2 to gradually increase along the direction from the heat sink 40 to the package structure 1, thereby ensuring a reliable connection between the solder layer 2 and the first solder surface 11 and the second solder surface 411.

[0050] Furthermore, as shown in Figure 4, due to the aforementioned relationship between the first welding surface 11 and the second welding surface 411, the angle α between the portion of the surface of the package structure 1 facing the heat sink 40 located on the periphery of the first welding surface 11 and the outer surface of the solder layer 2 can be a right angle or an obtuse angle, for example, 90°, 100°, or 105°. This helps to reduce the stress on the solder layer 2, thereby improving the welding reliability of the first welding surface 11 and the second welding surface 411.

[0051] After understanding the design principles of the power module provided in this application, the manufacturing process of the power module will be introduced next.

[0052] First, referring to Figure 5, which illustrates the structure of the package structure 1 and the heat sink 40 before soldering. In this step, the surface of the protrusion 41 of the heat sink 40 can be contoured according to the bending shape of the first soldering surface 11 of the package structure 1, so that the bending direction of the second soldering surface 411 of the protrusion 41 is consistent with the bending direction of the first soldering surface 11. In one possible embodiment, the curvature of the second soldering surface 411 can also be made consistent with or substantially the same as the curvature of the first soldering surface 11, which is beneficial to improving the thickness uniformity of the solder layer 2 subsequently formed between the first soldering surface 11 and the second soldering surface 411.

[0053] It is worth mentioning that the protrusion 41 of the heat sink 40 can be obtained by processes such as CNC machining, stamping, or cold spraying. In addition, the first welding surface 11 of the package structure 1 can be formed during the preparation of the package structure 1, and its formation method can be, but is not limited to, stamping.

[0054] Then, the solder between the first welding surface 11 and the second welding surface 411 is melted so that the solder is evenly filled between the first welding surface 11 and the second welding surface 411 to form the solder layer 2 as shown in FIG4.

[0055] Understandably, since the first welding surface 11 and the second welding surface 411 have the same bending direction and similar shape before the solder melts, even if the curvature of the first welding surface 11 and the second welding surface 411 changes during the welding heating process, the degree of change is similar, so its impact on the distribution of solder between the first welding surface 11 and the second welding surface 411 is small. This helps to improve the uniformity of solder filling between the first welding surface 11 and the second welding surface 411, which can reduce the risk of voids between the package structure 1 and the heat sink 40, thereby improving the welding reliability of the package structure 1 and the heat sink 40, and thus helping to improve the heat dissipation efficiency of the power module.

[0056] It is worth mentioning that the above only introduces the main steps involved in the welding of the packaging structure 1 and the heat sink 40 during the processing of the power module, and the processing steps of the power module are not limited to this. For example, it is also necessary to plate a layer of nickel or the like on the surface of the heat sink 40 to form an anti-corrosion layer structure on the surface of the heat sink 40. The order of the plating step of the heat sink 40 and the formation step of the second welding surface 411 of the protrusion 41 is not limited. For example, the protrusion 41 can be shaped and processed to form the second welding surface 411 after the plating is completed.

[0057] In addition, to improve the uniformity of the solder layer 2 thickness, in some embodiments of this application, a support column (not shown in FIG. 4) can be formed on the second welding surface 411 of the protrusion 41. When the first welding surface 11 and the second welding surface 411 are welded, the support column can be made to abut against the first welding surface 11. In this way, the spacing between the first welding surface 11 and the second welding surface 411 can be controlled by the support column, which can effectively improve the uniformity of solder distribution between the first welding surface 11 and the second welding surface 411.

[0058] Considering the risk of solder overflow during the melting process, and the fact that solder is typically conductive, excessive solder overflow could increase the risk of electrical conductivity between the pins 3 (used to lead out electrical components from the package structure 1) and the heat sink 40. To address this issue, referring to Figure 6, which is a schematic diagram of another structure of the power module provided in this embodiment, the heat sink 40 further includes an overflow groove 42. This overflow groove 42 is recessed along the direction from the package structure 1 to the heat sink 40, and is arranged around the protrusion 41. This allows the solder overflowing during the soldering heating process to flow into the overflow groove 42, thereby ensuring a sufficiently large insulation distance between the pins 3 (used to lead out electrical components from the package structure 1) and the heat sink, thus improving the operational safety of the power module.

[0059] Additionally, it is understood that in order to ensure that the overflowing solder can flow to the overflow groove 42, the distance between the overflow groove 42 and the protrusion 41 cannot be too large. Therefore, in one possible embodiment, along the direction from the package structure 1 to the heat sink 40, the projection of the package structure 1 on the surface of the heat sink 40 can cover the overflow groove 42.

[0060] In practical applications, the distance between the overflow groove 42 and the protrusion 41 can be 0 to 20 mm. For example, in the embodiment shown in Figure 6, the distance between the overflow groove 42 and the protrusion 41 is 5 mm. In the embodiment shown in Figure 7, the distance between the overflow groove 42 and the protrusion 41 is 0 mm. In other possible embodiments, the distance between the overflow groove 42 and the protrusion 41 can also be 8 mm or 10 mm, etc.

[0061] Figure 8 is a schematic diagram of another structure of the power module provided in an embodiment of this application. As shown in Figure 8, in this embodiment, the heat sink 40 further includes a solder resist layer 43, which is disposed on the surface of the heat sink 40 facing the package structure 1, and the solder resist layer 43 is disposed around the protrusion 41 to control the deposition site of solder during the soldering process. In this application, the reflow resistance temperature of the solder resist layer 43 is greater than that of the solder layer 2, so that the solder resist layer 43 can be prevented from melting during the heating and melting of the solder, which is beneficial to improving the structural reliability of the heat sink 40.

[0062] In practical applications, when selecting the material for the solder resist layer 43, its reflow resistance temperature can be greater than or equal to 250℃, and it should not react with the flux to ensure structural stability. Furthermore, during long-term operation of the power module, the solder resist layer 43 should withstand a temperature greater than or equal to 150℃, and it should not peel off from the nickel plating or copper surface of the heat sink 40, thus ensuring the structural stability of the heat sink 40.

[0063] In this embodiment of the application, the thickness of the solder resist layer 43 is less than the thickness of the protrusion 41 along the direction from the package structure 1 to the heat sink 40. In one possible embodiment, the thickness t of the solder resist layer 43 and the thickness T of the protrusion 41 can satisfy: t ≤ 0.8T. This ensures that the solder resist layer 43 can effectively resist soldering while ensuring that the second welding surface 411 of the protrusion 41 can reliably bond with the solder.

[0064] In addition, there may be a gap between the solder resist layer 43 and the protrusion 41, which can serve as an overflow groove 42 to collect the solder that overflows during the welding heating process.

[0065] In the power module provided in the above embodiments, the first welding surface 11 is a concave surface curved along the direction from the heat sink 40 to the packaging structure 1, and the second welding surface 411 is a convex surface curved along the direction from the heat sink 40 to the packaging structure 1. In other possible embodiments of this application, the first welding surface 11 and the second welding surface 411 may also adopt other possible configurations. For example, referring to FIG9, FIG9 is another structural schematic diagram of the power module provided in an embodiment of this application. In this embodiment, the first welding surface 11 is a convex surface curved along the direction from the packaging structure 1 to the heat sink 40, and the second welding surface 411 is a concave surface curved along the direction from the packaging structure 1 to the heat sink 40. As in the power module shown in FIG10, both the first welding surface 11 and the second welding surface 411 are planar. In other embodiments, the first welding surface 11 and the second welding surface 411 may also be other regular or irregular curved surfaces, which are not listed here, but should all be understood to fall within the protection scope of this application.

[0066] It is worth noting that this application does not limit the correspondence between the number of encapsulation structures 1 and heat sinks 40. For example, in the embodiment shown in FIG4, multiple encapsulation structures 1 are welded to the same heat sink 40, wherein the arrangement of the first welding surfaces 11 of the multiple encapsulation structures 1 can be the same or different. In addition, in other possible embodiments, the encapsulation structures 1 and heat sinks 40 can be welded in a one-to-one correspondence.

[0067] This application does not limit the specific structure of the packaging structure 1. In one possible embodiment, as shown in FIG11a, FIG11a is a partial schematic diagram of a packaging structure of a power module provided in an embodiment of this application. The packaging structure 1 may include a substrate 12 and a chip 13. The substrate 12 includes a first surface 124 and a second surface 125 disposed opposite to each other. In this embodiment, the chip 13 is located on the first surface 124 of the substrate 12 and is electrically connected to the substrate 12. This application does not limit the number of chips 13 in the power module. Exemplarily, there may be one or more chips 13, all of which may be located on the first surface 124 of the substrate 12. The chip 13 may include an integrated circuit (IC) chip, an insulated gate bipolar transistor (IGBT), a metal-oxide-semiconductor field-effect transistor (MOSFET), or a power transistor, etc.

[0068] Referring again to Figure 11a, the substrate 12 may include a ceramic substrate 121 and a metal layer, with the metal layer fixed to the surface of the ceramic substrate 121. For example, the substrate 12 may include two metal layers, fixed to opposite sides of the ceramic substrate 121 along the direction from the first surface 124 to the second surface 125. For ease of explanation, in this embodiment, the two metal layers are referred to as the first metal layer 122 and the second metal layer 123, respectively. The first metal layer 122 can be used to mount the chip 13. The chip 13 can be electrically connected to the first metal layer 122 via bonding wires 4 made of aluminum, copper, silver, or their alloys, or via a clip soldering process based on metals such as aluminum, copper, silver, or their alloys, or other possible methods, which will not be listed here.

[0069] In addition, the first metal layer 122 can also be used to mount electrical components such as inductors, resistors, or capacitors (not shown in Figure 11a). The chip 13 and these electrical components can be fixed to the surface of the first metal layer 122 by processes such as reflow soldering. Alternatively, the chip 13 and these components can be pre-packaged using ball grid array package (BGA), quad flat non-leaded package (QFN), small out-line package (SOP), transistor outline (TO), or any other packaging form before being fixed to the surface of the first metal layer 122.

[0070] In one embodiment, the ceramic substrate 121 can be made of relatively low-cost materials such as alumina or aluminum nitride to reduce the overall cost of the power module. The first metal layer 122 and the second metal layer 123 can each be copper layers, in which case the substrate 12 is a direct-bonded copper (DBC) ceramic substrate. In other embodiments, the first metal layer 122 and the second metal layer 123 can also be aluminum layers, in which case the substrate 12 is a direct-bonded aluminum (DBA) ceramic substrate. In other possible embodiments of this application, the substrate 12 can also be other forms of metal-clad insulating board such as an active metal bonding (AMB) copper substrate, an insulated metal substrate (IMS), or a printed circuit board (PCB), and is not limited thereto.

[0071] It is understood that, in the embodiments of this application, the second surface 125 of the substrate 12 may include the aforementioned first welding surface 11, and when the packaging structure of the power module adopts the arrangement shown in FIG11a, the first welding surface 11 may be at least a portion of the second surface 125. This ensures efficient conduction of heat generated by the chip 13 and the substrate 12 during operation to the heat sink, thereby improving the heat dissipation performance of the power module.

[0072] In addition, it is worth mentioning that the surface of the encapsulation structure 1 facing the heat sink 40 in the above embodiment can also be understood as the second surface 125 of the substrate 12, and the direction from the encapsulation structure 1 to the heat sink 40 is also the direction from the first surface 124 to the second surface 125, and the direction from the heat sink 40 to the encapsulation structure 1 is also the direction from the second surface 125 to the first surface 124.

[0073] Additionally, referring to Figure 11b, which is a partial schematic diagram of another structure of the power module packaging structure provided in this embodiment, the power module further includes a metal-clad insulating plate 14. The metal-clad insulating plate 14 is connected to the first surface 124 of the substrate 12. The connection method can be, but is not limited to, welding, sintering, or bonding, thereby achieving thermally conductive contact between the substrate 12 and the metal-clad insulating plate 14.

[0074] It is understood that in the embodiment shown in FIG11b, the substrate 12 can be made of a metal material with good thermal conductivity, for example, the substrate 12 can be a copper plate or an aluminum plate.

[0075] Furthermore, as shown in Figure 11b, chip 13 is located on the side of the metal-clad insulating plate 14 facing away from the substrate 12, and chip 13 is electrically connected to the metal-clad insulating plate 14. Therefore, the heat generated by chip 13 during operation can be transferred to the substrate 12 through the metal-clad insulating plate 14, and then dissipated to the outside through the substrate 12, thereby achieving heat dissipation for chip 13.

[0076] Referring again to FIG11b, along the direction from the first surface 124 to the second surface 125, the projection of the metal-coated insulating plate 14 falls within the outline of the projection of the substrate 12, and the projected area of ​​the metal-coated insulating plate 14 is smaller than the projected area of ​​the substrate 12. Based on this, it can be understood that in this embodiment of the present application, the first welding surface 11 of the packaging structure 1 mentioned above can be located on the side surface of the substrate 12 facing the heat sink. This facilitates the increase in the design size of the first welding surface 11, thereby improving the heat exchange efficiency between the first welding surface 11 and the second welding surface 411, and further improving the efficiency of heat conduction from the substrate 12 to the base plate 14 to the heat sink 40.

[0077] It is understood that the surface of the packaging structure 1 facing the heat sink 40 in the above embodiment can also be understood as the second surface 125 of the substrate 12.

[0078] In this application, the radiator 40 can be a liquid-cooled radiator or an air-cooled radiator. A liquid-cooled radiator is a radiator 40 that exchanges heat through the flow of a liquid working fluid, and it has high heat dissipation efficiency. An air-cooled radiator is a radiator that exchanges heat through the flow of air. It is understood that an air-cooled radiator typically includes a fan to accelerate the airflow speed, thereby improving the heat dissipation effect.

[0079] This application does not limit the packaging form of the packaging structure 1. In the above embodiments, the packaging structure 1 is described using molding packaging as an example. Molding packaging involves placing a carrier substrate carrying various electrical components into a special injection mold, using softened epoxy resin or other molding compound as the encapsulation material, and encapsulating the electrical components under certain pressure and temperature conditions to protect the internal components. That is to say, in the above embodiments, the packaging structure 1 includes a packaging body such as molding compound, wherein the packaging body can be used to encapsulate electrical components such as a substrate, chip, inductor, resistor or capacitor, and at least a portion of the pins for bringing out the electrical interface of the chip.

[0080] In other embodiments of this application, the packaging structure 1 may also adopt a housing packaging method as shown in FIG12. Housing packaging is a packaging method in which a housing and a carrier substrate carrying the aforementioned electrical components form a cavity, and filler adhesive is injected into the cavity to protect the electrical components. That is, in this embodiment, the packaging body of the packaging structure 1 may include a housing and filler adhesive (e.g., silicone gel or epoxy potting compound) to encapsulate the substrate, chip, inductor, resistor, or capacitor, and at least a portion of the pins for leading out the electrical interface of the chip. As can be seen from FIG12, the specific arrangement of the first welding surface 11 of the housing packaging structure 1, and the connection method between the packaging structure 1 and the heat sink 40, can refer to any of the above embodiments, and will not be elaborated here.

[0081] In other embodiments of this application, the power module packaging structure 1 may also adopt other possible packaging forms, but regardless of the packaging form adopted, the chip 13 and the first surface 124 of the substrate 12 are disposed in the package. In addition, the specific arrangement of the first welding surface 11 of the packaging structure 1 and the connection method between the packaging structure 1 and the heat sink 40 can refer to any of the above embodiments, and will not be described in detail here.

[0082] In the various embodiments of this application, unless otherwise specified or in case of logical conflict, the terminology and / or descriptions between different embodiments are consistent and can be referenced in each other. Technical features in different embodiments can be combined to form new embodiments based on their inherent logical relationships.

[0083] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A power module with enhanced heat dissipation, characterized in that, The power module includes a substrate, a chip, a package, and a heat sink, wherein: The substrate includes a first side and a second side disposed opposite to each other, and the chip and the first side of the substrate are both disposed in the package. The heat sink is located on the side of the second surface away from the first surface; the second surface of the substrate includes a first welding surface, and the surface of the heat sink facing the substrate includes a protrusion, the surface of the protrusion including a second welding surface; the first welding surface and the second welding surface have the same bending direction, the first welding surface and the second welding surface are arranged opposite to each other, and the first welding surface and the second welding surface are welded together by a solder layer.

2. The power module as described in claim 1, characterized in that, Along the direction from the first surface to the second surface, the projection of the first welding surface covers the projection of the second welding surface, and the projected area of ​​the first welding surface is greater than the projected area of ​​the second welding surface.

3. The power module as described in claim 2, characterized in that, The angle between the portion of the second surface located on the periphery of the first welding surface and the outer surface of the solder layer is a right angle or an obtuse angle.

4. The power module as described in any one of claims 1 to 3, characterized in that, The first welding surface is a convex surface that is bent in the direction from the first surface to the second surface, and the second welding surface is a concave surface that is bent in the direction from the first surface to the second surface.

5. The power module as described in any one of claims 1 to 3, characterized in that, The first welding surface is a concave surface that bends along the direction from the second surface to the first surface, and the second welding surface is a convex surface that bends along the direction from the second surface to the first surface.

6. The power module as described in any one of claims 1 to 3, characterized in that, The first welding surface is a plane, and the second welding surface is a plane.

7. The power module according to any one of claims 1 to 6, characterized in that, The radiator includes an overflow groove that is recessed along the direction from the first surface to the second surface; the overflow groove is disposed around the protrusion.

8. The power module as described in claim 7, characterized in that, Along the direction from the first surface to the second surface, the projection of the substrate onto the surface of the heat sink covers the overflow groove.

9. The power module according to any one of claims 1 to 8, characterized in that, The surface of the heat sink facing the substrate includes a solder resist layer, which is disposed around the protrusion; the reflow temperature of the solder resist layer is higher than that of the solder layer.

10. The power module as described in claim 9, characterized in that, Along the direction from the first surface to the second surface, the thickness of the solder resist layer is less than the thickness of the protrusion.

11. The power module according to any one of claims 1 to 10, characterized in that, The chip is located on the first side of the substrate and is electrically connected to the substrate.

12. The power module according to any one of claims 1 to 10, characterized in that, The power module further includes a metal-clad insulating plate, which is connected to the first side of the substrate; the chip is located on the side of the metal-clad insulating plate opposite to the substrate, and the chip is electrically connected to the metal-clad insulating plate.

13. A power conversion device, characterized in that, It includes a circuit board and a power module as described in any one of claims 1 to 12, wherein the power module is electrically connected to the circuit board.

Images