Power module, power conversion equipment and lead frame

Abstract

The utility model relates to the technical field of power electronics, in particular to a power module, power conversion equipment and a lead frame. The power module comprises a substrate, an electronic element and at least one structural member. The substrate comprises a ceramic bottom plate and a first metal layer and a second metal layer which are arranged on the two surfaces of the ceramic bottom plate, the electronic element and each structural part are arranged on the surface, away from the ceramic bottom plate, of the first metal layer, and the brittleness of the structural parts is smaller than that of the ceramic bottom plate. In the direction perpendicular to the substrate, the orthographic projection of any structural member and the orthographic projection of the electronic element on the first metal layer are not overlapped. And each structural part is used for being pressed by an ejection column of a mold in the injection molding packaging process. In the injection molding process of the power module, the possibility that the ceramic bottom plate is stressed to generate undetectable microcracks can be reduced, the reliability of a product can be improved, and the yield of the power module in production can be improved.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to a power module, power conversion device and lead frame. Background Technology

[0002] Packaging is the process of mounting integrated circuits, discrete components, or other electronic components within a specific housing, providing functions such as electrical connection, physical protection, and heat dissipation. Traditional packaging technologies often use a substrate with a ceramic base to achieve high thermal conductivity and insulation withstand voltage, and then use injection molding to achieve encapsulation.

[0003] In the molding process of power modules, temperature changes can cause thermal stress inside the substrate, leading to warping and potentially causing adhesive overflow during molding. While extruding the substrate can suppress warping, the extrusion pressure may cause cracks in the ceramic base plate, affecting structural reliability and product yield. Utility Model Content

[0004] This application provides a power module, a power conversion device, and a lead frame. In the injection molding process, the power module can reduce the possibility of undetectable microcracks caused by stress on the ceramic base plate, thereby improving product reliability and increasing the yield of the power module in production.

[0005] In a first aspect, this application provides a power module, which includes a substrate, electronic components, and at least one structural component. The substrate includes a ceramic base plate and a first metal layer and a second metal layer disposed on two surfaces of the ceramic base plate. The electronic components and each structural component are disposed on the surface of the first metal layer away from the ceramic base plate. The structural components are less brittle than the ceramic base plate. Along the direction perpendicular to the substrate, the orthographic projection of any structural component and the electronic component on the first metal layer does not overlap.

[0006] In the injection molding process of the aforementioned power module, the structural component serves to withstand the pressure from the ejector pins of the upper mold, pressing the substrate against the lower mold. This mitigates warping of the substrate due to temperature changes and prevents injection molding material from intruding into the substrate surface facing the lower mold, thus affecting heat dissipation. The structural component is less brittle than the ceramic base plate, allowing it to better withstand pressure. By bearing the pressure from the ejector pins, the structural component prevents direct contact between the ejector pins and the substrate, providing a buffering and dissipating effect on force. This protects the ceramic base plate included in the substrate, reducing the possibility of undetectable microcracks forming in the ceramic base plate under stress, thereby improving product reliability and increasing the yield rate of the power module during production.

[0007] In one embodiment, along a direction perpendicular to the substrate, the contact area between each structural member and the first metal layer is greater than the contact area between the structural member and the ejector pin of the mold. The pressure applied by the ejector pin to the structural member can be transmitted and diffused within the structural member, thereby reducing the pressure per unit area ultimately transmitted to the substrate, and thus reducing the risk of the ceramic base plate in the substrate cracking under pressure.

[0008] In one embodiment, the power module includes a lead frame; the lead frame includes multiple pins; each pin has a first connection segment and a second connection segment with an integral structure, the first connection segment being disposed on the surface of a first metal layer facing away from the ceramic substrate, one end of the second connection segment being connected to the first connection segment, and the other end of the second connection segment extending away from the first connection segment and suspended relative to the first metal layer, a portion of the first connection segment constituting a structural component. By using a portion of the lead frame to constitute a structural component, the complexity of the manufacturing process and cost are reduced.

[0009] In one embodiment, along an arrangement direction parallel to the substrate and perpendicular to the first and second connecting segments, the width of the first connecting segment is greater than the width of the second connecting segment. Increasing the area of ​​the first connecting segment improves warpage control and pressure uniformity, reduces the pressure per unit area transmitted to the substrate through the structural components, and lowers the possibility of cracks forming in the ceramic substrate under stress.

[0010] In one embodiment, at least one structural member has its two ends fixed to a first metal layer and its middle portion protruding away from the first metal layer. When the middle portion of the structural member receives pressure from the top column, the middle portion of the structural member is subjected to pressure and moves closer to the first metal layer. The structural deformation of the structural member absorbs part of the force, reducing the force transmitted to the substrate through the two ends of the structural member, thus achieving a force buffering effect.

[0011] In one embodiment, at least one auxiliary layer is disposed on the surface of at least one structural member facing away from the first metal layer along a direction perpendicular to the substrate. Each auxiliary layer is less brittle than the ceramic base plate. The stacking of auxiliary layers increases the thickness of the structural member, enhancing its pressure-absorbing effect when bearing the pressure of the top pillar. The auxiliary layers can be made of the same material as the structural member, reducing manufacturing complexity.

[0012] In one embodiment, at least one structural member has a dielectric protective layer covering the surface of the structural member facing away from the first metal layer. The dielectric protective layer is less brittle than the structural member, which can optimize the pressure buffering effect of the structural member and provide a certain degree of protection for the structural member.

[0013] In one embodiment, the dielectric protective layer includes at least one of an organic coating or a pre-cured material, which can be pre-formed during the fabrication of the structural component, simplifying the process.

[0014] In one embodiment, the structural component is connected to the first metal layer via solder, silver paste, or adhesive. When the structural component is soldered to the first metal layer, it can be welded using methods such as brazing, laser welding, or ultrasonic welding. When the structural component is bonded to the first metal layer using adhesive, it can be bonded using processes such as dispensing or coating. When the structural component is fixed to the first metal layer using silver paste, it can be connected using a silver sintering process. In the fabrication of a specific power module, a suitable connection method can be selected based on the material, structure, and implementation method of the structural component.

[0015] In one embodiment, at least one structural component is disposed at the edge or corner of the first metal layer. The distribution position of the structural component relative to the substrate needs to be adjusted specifically according to the specific structure of the power module.

[0016] In one embodiment, the power module includes a package that encapsulates a substrate, a first metal layer, electronic components, and each structural element.

[0017] Secondly, this application provides a power conversion device, which includes a circuit board and any of the power modules provided in the first aspect, wherein the power module is electrically connected to the circuit board. Because the power module structure is more reliable, it is beneficial to improve the performance of the power conversion device.

[0018] Thirdly, this application provides a powertrain, which includes a controller and a motor. The controller includes multiple power modules as described in the first aspect above; each power module is used to convert electrical energy supplied by a power source and output it to the motor. The power module structure has higher stability and reliability, which is beneficial to improving the efficiency of the powertrain.

[0019] Fourthly, this application provides an electric vehicle, which includes a power battery, wheels, and a powertrain as provided in the third aspect. The powertrain's power conversion device receives direct current (DC) from the power battery and converts it into alternating current (AC) for output to a motor, which drives the wheels. Electric vehicles including the aforementioned power module have better power performance.

[0020] Fifthly, this application provides a lead frame, which includes a frame and a plurality of pins. The frame is used to circumferentially surround the metal layer of a substrate. Each pin has an integrally formed first connecting segment and a second connecting segment. The first connecting segment is disposed on the surface of the metal layer of the substrate, and the second connecting segment is connected between the first connecting segment and the frame, with the second connecting segment suspended relative to the metal layer of the substrate. The brittleness of the first connecting segment is less than that of the ceramic base plate of the substrate. In the injection molding process, a portion of the first connecting segment of the lead frame can be used to bear the pressure of the mold's ejector pins, preventing the ejector pins from directly contacting the substrate, thus buffering and distributing the force, protecting the ceramic base plate included in the substrate, and reducing the possibility of undetectable microcracks forming in the ceramic base plate under stress.

[0021] The technical effects that can be achieved by the second to fifth aspects mentioned above can be referred to the corresponding effect descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0022] Figure 1a This is a schematic diagram of the injection molding packaging structure of a traditional power module;

[0023] Figure 1b This is a schematic diagram of a traditional power module.

[0024] Figure 2a This is a schematic diagram of a power module provided in an embodiment of this application;

[0025] Figure 2b This is a schematic diagram of the injection molding packaging structure of a power module provided in an embodiment of this application;

[0026] Figure 3 This is a partial structural schematic diagram of a power module provided in an embodiment of this application;

[0027] Figure 4 This is a partial structural cross-sectional schematic diagram of a power module provided in an embodiment of this application;

[0028] Figure 5a This is a partial structural cross-sectional schematic diagram of a power module provided in an embodiment of this application;

[0029] Figure 5b This is a partial structural cross-sectional schematic diagram of a power module provided in an embodiment of this application;

[0030] Figure 6 This is a partial structural cross-sectional schematic diagram of a power module provided in an embodiment of this application;

[0031] Figure 7a This is a partial structural cross-sectional schematic diagram of a power module provided in an embodiment of this application;

[0032] Figure 7b This is a partial structural cross-sectional schematic diagram of a power module provided in an embodiment of this application;

[0033] Figure 8a This is a schematic diagram of a power module provided in an embodiment of this application;

[0034] Figure 8b This is a schematic diagram of the injection molding packaging structure of a power module provided in an embodiment of this application;

[0035] Figure 9 This is a partial structural schematic diagram of a power module provided in an embodiment of this application;

[0036] Figure 10a This is a partial structural cross-sectional schematic diagram of a power module provided in an embodiment of this application;

[0037] Figure 10b This is a partial structural cross-sectional schematic diagram of a power module provided in an embodiment of this application;

[0038] Figure 10c This is a partial structural cross-sectional schematic diagram of a power module provided in an embodiment of this application;

[0039] Figure 10d This is a partial structural cross-sectional schematic diagram of a power module provided in an embodiment of this application;

[0040] Figure 10e This is a partial structural cross-sectional schematic diagram of a power module provided in an embodiment of this application;

[0041] Figure 10f This is a partial structural cross-sectional schematic diagram of a power module provided in an embodiment of this application;

[0042] Figure 11 This is a partial structural schematic diagram of a power module provided in an embodiment of this application;

[0043] Figure 12 This is a schematic diagram of the structure of a power conversion device provided in an embodiment of this application;

[0044] Figure 13 This application provides a schematic diagram of the structure of an electric vehicle.

[0045] Figure 14 This is a schematic diagram illustrating the working principle of a powertrain for an electric vehicle provided in an embodiment of this application.

[0046] Figure label:

[0047] 1-Substrate; 11-Ceramic base plate; 121-First metal layer; 122-Second metal layer; 3-Lead frame; 31-Second connector; 300'-Frame; 300-Pin; 301-First connector segment; 302-Second connector segment; 4-Structural component; 41-First connector; 42-Dielectric protection layer; 43-Auxiliary stack; 5-Package body;

[0048] 01-Base plate; 02-Power electronic device; 031-Upper mold; 032-Lower mold; 04-Packaging structure;

[0049] D - Top pillar; Q - Mold cavity. Detailed Implementation

[0050] In the field of power electronics, packaging technology uses insulating molding compounds to encapsulate integrated circuits and substrates into a single unit. Taking power module packaging as an example, such as... Figure 1a As shown, a base plate 01, on which a power electronic device 02 is mounted, is placed within a mold cavity Q formed by an upper mold 031 and a lower mold 032. The surface of the base plate 01 facing away from the power electronic device 02 abuts against the inner wall of the lower mold 032. Liquid molding compound is injected into the mold cavity Q. The cured molding compound encapsulates the base plate 01 and the integrated circuit 02 to form a complete mold cavity. Figure 1b The encapsulation structure 04 is shown. The surface of the base plate 01 facing the lower mold 032 needs to be exposed in the encapsulation structure 04 after encapsulation to facilitate heat dissipation of the power module. During injection molding, temperature changes can cause thermal stress inside the base plate 01, leading to warping. This can cause the encapsulating material to overflow between the base plate 01 and the lower mold 032, and also affect the heat dissipation performance of the power module. Therefore, the inner wall of the upper mold 031 includes a pusher D. This pusher D can abut against the base plate 01 during the injection molding process, applying pressure to the base plate 01 to reduce warping and prevent it from detaching from the inner wall of the lower mold 032. However, when the insulating base plate included in the base plate 01 is made of ceramic material, ceramic materials have low tensile strength, poor plasticity and toughness. The pressure from the pusher D may cause the ceramic material of the base plate 01 to crack, even affecting the insulation and withstand voltage performance of the base plate 01, and also impacting the structural stability and reliability of the power module.

[0051] Based on this, embodiments of this application provide a power module, a power conversion device, and a lead frame. The power module can provide pressure protection for a substrate containing ceramic materials during the injection molding process, preventing the substrate from warping without affecting the structural stability of the ceramic materials.

[0052] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0053] The terminology used in the following embodiments is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used in the specification and appended claims of this application, the singular expressions “a,” “an,” “the,” “the,” “the,” and “this” are intended to also include expressions such as “one or more” unless the context clearly indicates otherwise.

[0054] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0055] Figure 2a An example of a power module 10 provided in this application embodiment is illustrated. The power module 10 includes a substrate 1, electronic components 2, and at least one structural component 4. The substrate 1 is used to support the electronic components 2 and each structural component 4. The substrate 1 includes a ceramic base plate 11, a first metal layer 121, and a second metal layer 122. The ceramic base plate 11 includes two surfaces opposite each other along its thickness direction. The first metal layer 121 and the second metal layer 122 are respectively disposed on the two surfaces of the ceramic base plate 11. The substrate 1 has a sandwich-like structure. The electronic components 2 and each structural component 4 are disposed on the surface of the first metal layer 121 facing away from the ceramic base plate 11. The multiple electrical devices included in the electronic components 2 can be connected through the first metal layer 121 to form a functional circuit. The second metal layer 122 is located on the surface of the ceramic base plate 11 facing away from the first metal layer 121. The first metal layer 121 and the second metal layer 122 are insulated from each other by the ceramic base plate 11.

[0056] The ceramic substrate 11 can specifically be alumina (Al2O3) ceramic, silicon nitride (Si3N4) ceramic, aluminum nitride (AlN) ceramic, or zirconia-toughened alumina ceramic. The ceramic substrate 11 has good insulation and voltage resistance, preventing electrical connection between the first metal layer 121 and the second metal layer 122. In one embodiment, the first metal layer 121 and the second metal layer 122 are both copper layers, and the substrate 1 can be a double-sided copper-clad laminate. Specifically, the substrate 1 can be a direct-bonded copper (DBC) ceramic substrate or a direct copper bonding (DCB) ceramic substrate. Alternatively, the substrate 1 can also be an active metal brazing (AMB) ceramic substrate.

[0057] In one embodiment, electronic component 2 is a combination of various power electronic devices. These power electronic devices include integrated circuit (IC) chips, insulated-gate bipolar transistors (IGBTs), silicon carbide power transistors, silicon transistors, metal-oxide-semiconductor field-effect transistors (MOSFETs), and diodes, etc. The power electronic devices included in the power module 10 can be electrically connected to form a functional circuit.

[0058] In one embodiment, the power module 10 further includes a lead frame 3 disposed on the first metal layer 121, the lead frame 3 including multiple pins 300. In a specific structural design, the power electronic devices included in the electronic component 2 form functional circuits through circuit traces in the first metal layer 121, and are connected to external circuits through the multiple pins 300 of the lead frame 3. The first metal layer 121 can be divided into multiple sub-metal layers as needed, with adjacent sub-metal layers isolated from each other. Depending on the circuit connection requirements, the power electronic devices included in the electronic component 2 and the multiple pins 300 of the lead frame 3 can be disposed on different sub-metal layers. Each structural component 4 can be disposed on the same sub-metal layer as the electronic component 2, or on the same sub-metal layer as the lead frame 3, or independently on a separate sub-metal layer.

[0059] In one embodiment, the power module 10 is encapsulated into a package 5 using an injection molding process. The package 5 encapsulates and fixes the substrate 1, electronic components 2, and lead frame 3. The second metal layer 122 of the substrate 1 is exposed outside the package 5, away from the surface of the ceramic base plate 11. Each pin 300 of the lead frame 3 extends out of the package 5 from the end furthest from the substrate 1. During the injection molding of the power module 10, each structural component 4 is used to bear the pressure of the mold's top post D. The structural component 4 is less brittle than the ceramic base plate 11 and can better withstand pressure.

[0060] like Figure 2bAs shown, during injection molding, the power module is placed in cavity Q between upper mold 031 and lower mold 032. The second metal layer 122 of the substrate 1 is placed on the inner wall of the lower mold 032 facing the upper mold 031. Electronic components 2, lead frames 3, and each structural component 4 are disposed on the first metal layer 121. A portion of each pin 300 of the lead frame 3 extends out of cavity Q and is clamped between the upper mold 031 and lower mold 032. The top post D of the upper mold 031 extends towards the substrate 1 and presses against the structural component 4. The top post D of the upper mold 031 and the lower mold 032 can fix the substrate 1 relatively. During injection molding, the warpage deformation of the substrate 1 under the influence of temperature changes can be alleviated, which can meet the warpage control requirements of the substrate 1 in the injection molding of the power module 10. Maintaining good flatness of the substrate 1 is beneficial to enhancing the connection reliability of the various components of the power module 10 and can also improve the production yield of the power module 10. Since the top pillar D pressing structure 4 can keep the second metal layer 122 of the substrate 1 in good contact with the lower mold 032, the liquid injection plastic is not easy to enter between the second metal layer 122 and the inner wall of the lower mold 032, preventing the injection plastic from covering the surface of the second metal layer 122 and affecting the heat dissipation of the power module 10.

[0061] The structural component 4 is positioned between the top post D and the first metal layer 121 of the substrate 1, preventing the top post D from directly applying pressure to the substrate 1. The structural component 4 can withstand the pressure applied by the top post D to the substrate 1, and can buffer and distribute the pressure between the top post D and the substrate 1, thus mitigating the adverse effects of pressure transmission to the substrate 1 on the ceramic base plate 11.

[0062] It should be understood that the ejector pins D included in the upper mold 031 can be fixed ejector pins, that is, ejector pins D are relatively fixed relative to the upper mold 031, and their position will not change during the injection molding process. Alternatively, ejector pins D can be spring-loaded ejector pins, that is, ejector pins D can be moved relative to the upper mold 031 by means of cylinders, springs, etc., and during the injection molding process, as the injection plastic fills and solidifies in the mold cavity Q, ejector pins D can gradually move out of the mold cavity Q.

[0063] In one embodiment, combined with Figure 2a and Figure 2b In the power module 10 shown, the contact area between the top post D and the structural component 4 is smaller than the contact area between the structural component 4 and the first metal layer 121 of the substrate 1. The pressure applied by the top post D to the structural component 4 can be transmitted and diffused in the structural component 4 in a direction parallel to the substrate 1, thereby reducing the pressure per unit area that is ultimately transmitted to the substrate 1, which can reduce the risk of the ceramic base plate 11 in the substrate 1 cracking under pressure.

[0064] Combination Figure 3The diagram shows a partial top view of the power module 10. Viewing the structural member 4 and its corresponding top post D along a direction perpendicular to the substrate 1, the orthographic projection of the top post D onto the first metal layer 121 falls within the orthographic projection range of the structural member 4 onto the first metal layer 121. The orthographic projection of the top post D onto the structural member 4 also falls within the surface contour of the structural member 4 facing the top post D. The contact area between the structural member 4 and the first metal layer 121 of the substrate 1 is relatively large. Compared to the top post D directly contacting the substrate 1, the structural member 4 can cover a larger area of ​​the substrate 1, thus influencing a wider range of substrate 1 warpage. Therefore, the structural member 4 provides better warpage control over the substrate 1.

[0065] In this configuration, the projection of any structural component 4 onto the first metal layer 121 does not overlap with that of the electronic component 2. Each structural component 4 avoids the structure of the electronic component 2 itself and the related circuit connection structure of the electronic component 2, so as to prevent any impact on the formation of the functional circuit.

[0066] The distribution position of at least one structural member 4 relative to the substrate 1 needs to be adjusted specifically according to the specific structure of the power module 10. For example, if the corner of the substrate 1 of a power module 10 is prone to warping, at least one structural member 4 can be provided at the corner of the substrate 1. Alternatively, if the side of the substrate 1 of a power module 10 is prone to warping, at least one structural member 4 can be provided at the edge of the substrate 1. Or, if the center of the substrate 1 of a power module 10 is prone to warping, at least one structural member 4 can be provided at the center of the substrate 1. It should be understood that the structural members 4 are all provided on the surface of the first metal layer 121 of the substrate 1 facing away from the ceramic base plate 11.

[0067] In one embodiment, the power module 10 includes at least two structural members 4, which are distributed in different positions to withstand the pressure of the top post D during injection molding and packaging, thereby relieving the warping of the substrate 1 and providing pressure buffer protection for the ceramic base plate 11 of the substrate 1.

[0068] Next, the specific implementation of structural component 4 will be described using a partial structure of power module 10 as an example.

[0069] In one embodiment, such as Figure 4 As shown, structural component 4 is connected to the first metal layer 121 via a first connecting material 41, which can be solder, silver paste, or adhesive. When structural component 4 is soldered to the first metal layer 121, it can be welded by brazing, laser welding, ultrasonic welding, or other methods. When structural component 4 is bonded to the first metal layer 121 with adhesive, it can be bonded by dispensing, coating, or other processes. When structural component 4 is fixed to the first metal layer 121 with silver paste, it can be fixed to the first metal layer 121 by a silver sintering process.

[0070] exist Figure 4 In the illustrated structure, taking one pin 300 of the lead frame 3 as an example, pin 300 is fixed to the first metal layer 121 by a second connector 31. The second connector 31 needs to also function as a conductor to achieve circuit interconnection between the lead frame 3 and the first metal layer 121. The second connector 31 can be solder or silver paste. Pin 300 can be soldered to the first metal layer 121 by brazing, laser welding, ultrasonic welding, etc., or pin 300 can be fixed to the first metal layer 121 by sintering with silver paste. When both the first connector 41 and the second connector 31 are solder, they can be the same or different types.

[0071] In one embodiment, such as Figure 5a As shown, at least one structural member 4 has a relatively large thickness along the direction perpendicular to the substrate 1, thereby improving the pressure buffering effect. For structural reference, the thickness h2 of the structural member 4 is greater than the thickness h1 of the pin 300. Specifically, the pin 300 may be bent or deformed in the direction perpendicular to the substrate 1, and the thickness h1 of the pin 300 refers to the thickness of the portion of the pin 300 that connects to the first metal layer 121 of the substrate 1. It can be considered that within the contour range of the first metal layer 121, the thickness h2 of at least one structural member 4 is greater than the thickness h1 of the pin 300. It should be understood that the thickness of the pin 300 is also the thickness of the lead frame 3.

[0072] In one embodiment, such as Figure 5b As shown, along a direction perpendicular to the substrate 1, at least one auxiliary layer 43 is disposed on the surface of at least one structural member 4 facing away from the first metal layer 121. This at least one auxiliary layer 43 is sequentially stacked on the surface of the first metal layer 121 facing away from the ceramic base plate 11. The stacking of the auxiliary layers 43 increases the thickness of the structural member 4, enhancing its pressure-buffering effect when bearing the pressure of the top pillar D. Any two adjacent auxiliary layers 43, or between an auxiliary layer 43 and a structural member 4, can be connected by a first connecting material 41. When the first connecting material 41 is an adhesive, the good elasticity of the adhesive can improve the pressure-buffering effect of the structural member 4. The material, thickness, and size of each auxiliary layer 43 can be the same as or different from those of the structural member 4. When the auxiliary layers 43 and the structural member 4 are made of the same material, it can be considered as a stacked design of multiple structural members 4.

[0073] Figure 5a and Figure 5b The connectors 4 shown all improve the pressure protection effect by increasing the thickness of the connector layer 4. The increased thickness of the connector layer 4 allows the pressure to have a longer buffer path in the direction perpendicular to the substrate 1 when it is transmitted to the connector layer 4, thereby achieving a better pressure protection effect.

[0074] In some embodiments, the shape of structural member 4 is improved so that structural member 4 is arched or convex, thus possessing a certain pre-compression elasticity. When bearing the pressure of the top column D, structural member 4 can achieve a pressure buffering effect through its own structural deformation. Figure 6 As shown, the two ends of structural component 4 are fixed to the first metal layer 121, and the middle part protrudes away from the first metal layer 121. Therefore, there is a gap between the middle part of structural component 4 and the first metal layer 121, and structural component 4 is arched. When the middle part of structural component 4 receives the pressure of the top column D, the middle part of structural component 4 is subjected to pressure and moves closer to the first metal layer 121. The structure of structural component 4 deforms and absorbs part of the force, reducing the force transmitted to the first metal layer 121 through the two ends of structural component 4, thus playing a buffering role.

[0075] In some embodiments, such as Figure 7a As shown, along a direction perpendicular to the substrate 1, the surface of the structural member 4 facing away from the first metal layer 121 is covered with a dielectric protective layer. This additional structure on the surface of the structural member 4 enhances its cushioning effect. The dielectric protective layer 42 is less brittle than the structural member 4, optimizing the pressure cushioning effect of the structural member 4 and also providing some protection. The surface of the structural member 4 facing away from the first metal layer 121 is the surface of the structural member 4 used to bear the pressure of the top pillar D. The dielectric protective layer 42 can further cushion the pressure and improve the pressure protection effect. The dielectric protective layer 42 can be at least one of organic coatings and pre-cured materials, and can be pre-formed during the fabrication of the structural member 4, simplifying the process.

[0076] Among them, organic coatings are selected from materials with good elasticity after film formation, such as polyurethane coatings, acrylic elastic coatings, silicone rubber coatings, and epoxy-modified polyurethane coatings. Pre-curing materials include resin materials and plastic materials, and their pre-curing methods include, but are not limited to, UV curing and thermosetting. These protective layers 42 have better elasticity, can absorb more pressure, and further optimize the pressure buffering effect.

[0077] based on Figure 7a The structure shown, in one embodiment, is as follows: Figure 7b As shown, the dielectric protective layer 42 covers the surface of the structural component 4 facing away from the first metal layer 121 and its circumferential side. When the structural component 4 is fixed to the first metal layer 121 by the first connecting material 41, the dielectric protective layer 42 can also cover the circumferential side of the first connecting material 41.

[0078] It should be understood that the various implementations of the structural component 4 provided in the embodiments of this application can be combined and transformed for use to optimize the pressure buffering effect on the ejector pin D in the injection molding process as much as possible. For example, the thickened structural component 4 is also provided with a medium protection layer 42, or the structural component 4 with an auxiliary layer 43 is also provided with a medium protection layer 42.

[0079] This application embodiment also provides a power module 10, such as Figure 8a As shown, with Figure 2b The difference in the power module 10 shown is that the structural component 4 is formed by a portion of the lead frame 3. For example... Figure 8b As shown, in the injection molding process of the power module 10, the top post D abuts against the surface of the lead frame 3 facing away from the first metal layer 121, and the portion of the lead frame 3 for the top post D to press against constitutes the structural component 4. At this time, the lead frame 3 is used not only for circuit connection with the first metal layer 121, but also for bearing the pressure of the top post D. As an example, the lead frame 3 includes multiple pins 300, and the connector 4 is part of one of the pins 300.

[0080] like Figure 9 The diagram shows a partial top view of the power module 10, with a pin 300 and its corresponding top post D viewed along a direction perpendicular to the substrate 1. The orthographic projection of the top post D onto the first metal layer 121 falls within the orthographic projection range of the lead frame 3 onto the first metal layer 121. For ease of understanding, the structure of the pin 300 is divided into a first connecting segment 301 and a second connecting segment 302. The first connecting segment 301 and the second connecting segment 302 have an integral structure, meaning they can be integrally formed during manufacturing, reducing process complexity and cost. The first connecting segment 301 is disposed on the surface of the first metal layer 121 facing away from the ceramic substrate 11. One end of the second connecting segment 302 is connected to the first connecting segment 301, and the other end of the second connecting segment 302 extends away from the first connecting segment 301 and is suspended relative to the first metal layer 121. When the power module 10 is packaged, the end of the second connection segment 302 facing away from the first connection segment 301 protrudes outside the package of the power module 10 for connecting other electrical components. The first connection segment 301 forms the structural component 4; that is, the surface of the first connection segment 301 facing away from the first metal layer 121 receives the pressure from the top post D. The orthogonal projection of the top post D onto the pin 300 falls within the range of the first connection segment 301.

[0081] In one embodiment, along the arrangement direction parallel to the substrate 1 and perpendicular to the first connecting segment 301 and the second connecting segment 302, the width w1 of the first connecting segment 301 is greater than the width w2 of the second connecting segment 302. The first connecting segment 301 can cover a larger area of ​​the substrate 1, thus affecting a wider range of substrate 1 warping and providing better warping control. The increased area of ​​the first connecting segment 301 can further reduce the pressure per unit area transmitted to the substrate 1 through the structural member 4, reducing the possibility of cracks forming in the ceramic base plate 11 under stress.

[0082] It is understandable that, based on the different functional implementations of the power module 10, there will be multiple implementations of the shape of the lead frame 3 and the connection position between the lead frame 3 and the first metal layer 121. Figure 9 The pin 300 of the lead frame 3 shown is only one structural example. The embodiment of this application provides a solution in which a part of the lead frame 3 constitutes the structural component 4, including any implementation in which any part of the lead frame 3 forms the structural component 4. Any part of the lead frame 3 that can withstand the pressure of the top post D can be considered as part of the lead frame 3 constituting the structural component 4.

[0083] In one embodiment, such as Figure 10a As shown, the lead frame 3 is fixed to the first metal layer 121 by the second connector 31. At this time, the second connector 31 is selected from solder or silver paste with conductive function.

[0084] In one embodiment, such as Figure 10b As shown, the first connecting segment 301 of the pin 300 is thickened, making the thickness of the lead frame 3 at the first connecting segment 301 greater than the thickness of the pin 300 at the second connecting segment 302. The first connecting segment 301 is used to form the structural component 4, which is equivalent to increasing the thickness of the structural component 4, thereby improving the buffering effect.

[0085] In one embodiment, such as Figure 10c As shown, along a direction perpendicular to the substrate 1, at least one auxiliary stack 43 is provided on the surface of the first connection segment 301 of the pin 300 facing away from the first metal layer 121. The auxiliary stack 43 can also be connected to the first connection segment 301 by a second connector 31, which can be solder, silver paste, or adhesive. In this case, the auxiliary stack 43 can increase the thickness of the first connection segment 301, which is equivalent to increasing the thickness of the structural component 4, thus providing a good pressure buffering effect.

[0086] In one embodiment, such as Figure 10d As shown, the first connecting segment 301 of pin 300 is arched or convex and has a certain pre-compression elasticity. When the first connecting segment 301 constitutes the structural component 4 to bear the pressure of the top column D, the structural component 4 can achieve a pressure buffering effect through its own structural deformation.

[0087] In one embodiment, such as Figure 10e and Figure 10f As shown, when a dielectric protective layer 42 is added to the surface of the first connection segment 301 of pin 300 facing away from the first metal layer 121, and this first connection segment 301 constitutes the structural member 4 to bear the pressure of the top post D, the buffering effect can be enhanced. The dielectric protective layer 42 can be as follows: Figure 10e The diagram shows only the surface of the first connecting segment 301 facing away from the first metal layer 121, or it can be as follows: Figure 10f As shown, it simultaneously wraps around the circumferential side of the first connecting segment 301.

[0088] In summary, the power module 10 provided in this application embodiment has a structural member 4 disposed on the surface of the substrate 1 where the electronic components 2 are disposed. During the injection molding and packaging process of the power module 10, the structural member 4 is used to withstand the pressure of the top post D of the upper mold 031, pressing the substrate 1 against the lower mold 032. On the one hand, this can alleviate the warping phenomenon of the substrate 1 due to temperature changes, and on the other hand, it can prevent the injection plastic from intruding into the surface of the substrate 1 facing the lower mold 032, affecting heat dissipation, which is beneficial to improving the yield of the power module 10 in production. The structural member 4 withstands the pressure of the top post D, preventing the top post D from directly contacting the substrate 1, thus playing a role in buffering and distributing force, protecting the ceramic base plate 11 included in the substrate 1, reducing the possibility of undetectable microcracks in the ceramic base plate 11 under stress, and improving the reliability of the product.

[0089] Based on the above embodiments, this application also provides a lead frame 3, such as... Figure 11 As shown, the lead frame 3 includes a frame 300' and a plurality of pins 300. The frame 300' is circumferentially surrounding the first metal layer 121 of the substrate 1, and a gap exists between the frame 300' and the first metal layer 121 of the substrate 1. Each pin can be referenced... Figure 9 and Figures 10a to 10f As shown, pin 300 includes a first connecting segment 301 and a second connecting segment 302. The first connecting segment 301 is disposed on the surface of the first metal layer 121 of the substrate 1, and the second connecting segment 302 connects the first connecting segment 301 and the frame 300'. Taking one pin 300 as an example, the first connecting segment 301 of this pin 300 can withstand the pressure of the top post D during the injection molding and packaging of the power module 10, thereby suppressing the warping of the substrate 1 by utilizing the lead frame 3. The first connecting segment 301 blocks the pressure between the top post D and the first metal layer 121 of the substrate 1, so that the top post D does not directly apply pressure to the substrate 1. The first connecting segment 301 can withstand the pressure applied by the top post D to the substrate 1, and can play a role in buffering and distributing pressure between the top post D and the substrate 1, which can alleviate the adverse effects of pressure transmission to the substrate 1 on the ceramic base plate 11.

[0090] In one embodiment, the electronic components 2 of the power module 10 provided in this application can be connected to the first metal layer 121 of the substrate 1 to form a power conversion circuit. This power conversion circuit can be used to realize one of the following circuit conversions: DC to AC, AC to DC, and DC to DC.

[0091] Power modules are widely used in electric vehicles, new energy, photovoltaics, wind power, and other fields for managing and regulating power transmission and conversion. They achieve excellent performance, including high voltage, high current, stable temperature, and low electromagnetic radiation. The main functions of a power module include voltage conversion, current control, and reversible conversion. Voltage conversion transforms the power supply voltage from one level to another, meeting the needs of different devices or systems. Current control regulates the current to ensure it remains within acceptable limits, preventing overcurrent damage to equipment or circuits. Reversible conversion converts direct current (DC) to alternating current (AC) or vice versa.

[0092] In consumer electronics, power modules are primarily used in power adapters, inverters, and frequency converters. In the power energy sector, they are mainly used in solar inverters and wind power converters. In energy storage, they are primarily used in energy storage converters or DC-DC converters. In automotive electronics, power modules are mainly used in electric vehicle motor controllers, on-board chargers (OBCs), microcontroller units (MCUs), and generator control units (GCUs).

[0093] Figure 12 This is a schematic diagram of a power conversion device provided in an embodiment of this application. (Reference) Figure 12 As shown, the power conversion device includes a power module 10, a circuit board 20, and a heat sink 30. The power module 10 is electrically connected to the circuit board 20, and the heat sink 30 has thermally conductive contact with the power module 10 to dissipate heat from the power module 10. In this application, the circuit board 20 can be, for example, a printed circuit board (PCB). The power module 10 is the core component of the photovoltaic inverter 100 that realizes the power conversion function. The power module 10 may 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 20 through pins, thereby utilizing the circuit board 20 to provide current or voltage input and output, as well as power supply functions, to the power module 10. Because the power module 10 has high reliability, it is beneficial to improve the performance of the power conversion device.

[0094] As an example, this application embodiment provides a such Figure 13The electric vehicle shown here refers to a wheeled device driven or towed by a power unit. In one embodiment, electric vehicles include passenger cars, commercial vehicles, or special-purpose vehicles such as emergency rescue vehicles, water trucks, sewage suction trucks, cement mixer trucks, crane trucks, and medical vehicles. Exemplarily, electric vehicles include pure electric vehicles (PEV / BEV), hybrid electric vehicles (HEV), range-extended electric vehicles (REEV), and plug-in hybrid electric vehicles (PHEV).

[0095] like Figure 13 As shown, the electric vehicle includes a power battery 4000, wheels 3000, a vehicle body 2000, and a powertrain 1000. The powertrain 1000, power battery 4000, and wheels 3000 are assembled on the vehicle body 2000.

[0096] like Figure 14 As shown, the powertrain 1000 includes a motor controller 100 and a motor 200. The motor controller 100 receives DC power from the power battery 4000 and outputs AC power to the motor 200. The motor 200 receives the AC power output from the motor controller 100 and drives the wheels 3000 of the electric vehicle. In one embodiment, the powertrain 100 integrates the motor 200 and the motor controller 100 into a single housing, increasing the integration density of the powertrain 1000, reducing its size and cost, facilitating a lightweight design, and improving power density.

[0097] In this embodiment of the application, the motor controller 100 includes a plurality of power modules 10 as described above. Each power module 10 can form a power conversion circuit for receiving DC power from the power battery 4000 and outputting AC power to the motor 200 to drive the motor 200, thereby driving the electric vehicle.

[0098] 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, characterized by The power module includes a substrate, electronic components, and at least one structural component; the substrate includes a ceramic base plate and a first metal layer and a second metal layer disposed on two surfaces of the ceramic base plate, the electronic components and each of the structural components are disposed on the surface of the first metal layer opposite to the ceramic base plate, and the structural components are less brittle than the ceramic base plate. Along a direction perpendicular to the substrate, the orthographic projection of any of the structural components and the electronic components on the first metal layer does not overlap.

2. The power module of claim 1, wherein, The power module includes a lead frame, and the lead frame includes multiple pins; Each of the pins has a first connection segment and a second connection segment of an integral structure. The first connection segment is disposed on the surface of the first metal layer away from the ceramic substrate. One end of the second connection segment is connected to the first connection segment, and the other end of the second connection segment extends away from the first connection segment and is suspended relative to the first metal layer. A portion of the first connection segment constitutes the structural component.

3. The power module of claim 2, wherein, Along a connection direction parallel to the substrate and perpendicular to the first connecting segment and the second connecting segment, the width of the first connecting segment is greater than the width of the second connecting segment.

4. The power module as described in any one of claims 1-3, characterized in that, At least one of the structural members has its two ends fixed to the first metal layer and its middle portion protruding away from the first metal layer.

5. The power module of any one of claims 1-4, wherein, Along a direction perpendicular to the substrate, at least one of the structural members has at least one auxiliary stack on the surface opposite to the first metal layer, and each of the auxiliary stacks is less brittle than the ceramic substrate.

6. The power module of any one of claims 1-5, wherein, At least one of the structural components has a dielectric protective layer covering the surface of the component facing away from the first metal layer, the dielectric protective layer being less brittle than the structural component.

7. The power module of claim 6, wherein, The protective layer for the medium includes at least one of organic coatings or pre-cured materials.

8. The power module of any one of claims 1-7, wherein, The structural component is connected to the first metal layer by solder, silver paste, or adhesive.

9. The power module of any one of claims 1-8, wherein, At least one of the structural components is disposed at the edge or corner of the first metal layer.

10. A power conversion device, characterized by, It includes a circuit board and a power module as described in any one of claims 1-9, wherein the power module is electrically connected to the circuit board.

11. A leadframe, characterized by, The lead frame is used to connect the substrate of the power module; The lead frame includes a frame and a plurality of pins, the frame being used to circumferentially surround the substrate. Each of the pins has a first connecting segment and a second connecting segment of an integral structure, the first connecting segment being disposed on the surface of the substrate, and the second connecting segment being connected between the first connecting segment and the frame; The first connecting segment is less brittle than the ceramic base plate of the substrate.

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