Power module
By setting an insulating structure in the power module to form a physical isolation between the insulating layer and the conductive layer, the problem of breakdown leakage caused by silicone breakdown is solved, and the insulation performance and reliability are improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SUNGROW POWER SUPPLY CO LTD
- Filing Date
- 2025-04-27
- Publication Date
- 2026-05-05
AI Technical Summary
Existing power modules suffer from silicone breakdown under high voltage, leading to breakdown leakage between the substrate and the heat sink, resulting in poor insulation performance.
An insulating structure is placed on the side of the insulating layer facing the conductive layer in the power module and located on the outer periphery of the conductive layer to form a physical isolation structure, increase the creepage distance, and avoid breakdown leakage.
This improves the insulation performance and reliability of the power module, prevents direct breakdown of the electrical connection path between the substrate and the heat sink, and ensures electrical safety.
Smart Images
Figure CN224205524U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of power modules, specifically to a power module. Background Technology
[0002] Power modules are power semiconductor devices used to convert and control electrical energy. For example, in a solar photovoltaic power generation system, an inverter composed of power modules can convert the direct current generated by photovoltaic cells into alternating current for use in homes or on the power grid.
[0003] In a power module, the substrate serves as a carrier, with a chip layer on one side and a heat sink on the other. The power module insulates the substrate and heat sink with silicone potting. However, under high voltage, the silicone can still break down, causing leakage between the substrate and the heat sink, resulting in poor insulation performance of the power module. Utility Model Content
[0004] This application provides a power module that can solve the problem of low insulation performance in existing power modules.
[0005] To achieve the above objectives, the power module provided in this application includes:
[0006] The heat dissipation base has a support surface;
[0007] The substrate includes an insulating layer and a conductive layer stacked together, with the side of the insulating layer facing away from the conductive layer connected to a carrier surface.
[0008] The chip layer is disposed on the side of the conductive layer away from the insulating layer and is electrically connected to the conductive layer;
[0009] An insulating structure is disposed on the side of the insulating layer facing the conductive layer and located on the outer periphery of the conductive layer.
[0010] In some embodiments of this application, the insulating structure is a closed ring structure and is disposed around the outer periphery of the conductive layer.
[0011] In some embodiments of this application, in the thickness direction of the substrate, the insulating structure has a first thickness T1 mm and the conductive layer has a second thickness T2 mm, wherein T1 > T2.
[0012] In some embodiments of this application, the insulating structure has a first thickness T1 mm in the thickness direction of the substrate, and there is a first distance D1 mm between the conductive layer and the carrier surface, wherein T1 ≥ 1.5 × D1.
[0013] In some embodiments of this application, the power module further includes:
[0014] A thermally conductive connection layer is disposed on the side of the insulating layer facing the bearing surface, and is used to connect the insulating layer and the bearing surface.
[0015] In some embodiments of this application, the power module further includes:
[0016] The encapsulation layer covers the insulating structure, chip layer, conductive layer, insulating layer and extends to the carrier surface.
[0017] In some embodiments of this application, there are multiple substrates, and each substrate is spaced apart on the bearing surface. Each substrate has a chip layer on the side of its conductive layer away from the insulating layer, and the chips in two adjacent chip layers are electrically connected by connecting wires.
[0018] In some embodiments of this application, the insulating layer and the insulating structure are an integral structure.
[0019] In some embodiments of this application, the insulating layer and the insulating structure are bonded together with adhesive.
[0020] In some embodiments of this application, the insulating structure is made of at least one of ceramics, glass, epoxy resin, and polytetrafluoroethylene.
[0021] The above-mentioned technical solution of this application has at least the following beneficial effects:
[0022] In this technical solution, the insulating structure is disposed on the side of the insulating layer facing the conductive layer and located on the outer periphery of the conductive layer. In other words, the insulating structure forms a physical isolation structure between the heat sink and the conductive layer and occupies a certain space, making the originally relatively direct electrical connection path between the heat sink and the conductive layer more tortuous. This increases the creepage distance between the conductive layer and the heat sink, which can, to some extent, prevent breakdown leakage between the substrate and the heat sink, thereby improving the insulation performance of the power module. Attached Figure Description
[0023] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0024] Figure 1 This is a perspective view of a power module according to an embodiment of this application;
[0025] Figure 2 yes Figure 1 A cross-sectional view of the power module in the illustrated embodiment;
[0026] Figure 3 yes Figure 2 Enlarged view of part A in the image;
[0027] Figure 4 This is a cross-sectional view of another power module in an embodiment of this application.
[0028] Explanation of reference numerals in the attached figures:
[0029] 1-Heat dissipation base; 11-Bearing surface; 2-Substrate; 21-Insulating layer; 211-First surface; 212-Second surface; 22-Conductive layer; 221-Mounting surface; 3-Chip layer; 4-Insulating structure; 41-Insulating surface; 5-Thermal conductive connection layer; 6-Encapsulation layer; 7-Connecting wire. Detailed Implementation
[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0031] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.
[0032] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.
[0033] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, a direct connection, or an indirect connection through an intermediate medium; or they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0034] This application provides a power module, which will be described in detail below. It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments of this application. Furthermore, the descriptions of each embodiment have their own emphasis; parts not described in detail in a certain embodiment can be referred to in the relevant descriptions of other embodiments.
[0035] Power modules are power semiconductor devices used to convert and control electrical energy. For example, in a solar photovoltaic power generation system, an inverter composed of power modules can convert the direct current generated by photovoltaic cells into alternating current for use in homes or on the power grid.
[0036] In a power module, the substrate serves as a carrier, with a chip layer on one side and a heat sink on the other. The power module insulates the substrate and heat sink with silicone potting. However, under high voltage, the silicone can still break down, causing leakage between the substrate and the heat sink, resulting in poor insulation performance of the power module.
[0037] The substrate, as a crucial carrier in the power module, plays a vital supporting role. Specifically, one side of the substrate houses the chip layer, which is the core area for realizing various electronic functions in the entire module; while the other side of the substrate is equipped with a heat dissipation base to dissipate the heat generated by the chips during operation, ensuring the stable operation of the power module.
[0038] Therefore, the power module provided in this application includes a heat sink, a substrate, a chip layer, and an insulating structure. The heat sink has a support surface, and the substrate includes an insulating layer and a conductive layer stacked together, with the side of the insulating layer facing away from the conductive layer connected to the support surface. The chip layer is disposed on the side of the conductive layer away from the insulating layer and is electrically connected to the conductive layer. The insulating structure is disposed on the side of the insulating layer facing the conductive layer and is located on the outer periphery of the conductive layer.
[0039] In this technical solution, the insulating structure is disposed on the side of the insulating layer facing the conductive layer and located on the outer periphery of the conductive layer. In other words, the insulating structure forms a physical isolation structure between the heat sink and the conductive layer and occupies a certain space, making the originally relatively direct electrical connection path between the heat sink and the conductive layer more tortuous. This increases the creepage distance between the conductive layer and the heat sink, which can, to some extent, prevent breakdown leakage between the substrate and the heat sink, thereby improving the insulation performance and reliability of the power module.
[0040] Figure 1 This is a perspective view of a power module according to an embodiment of this application. Figure 2 yes Figure 1 A cross-sectional view of the power module in the illustrated embodiment. Please refer to... Figure 1 and Figure 2The power module includes a heat sink 1, a substrate 2, a chip layer 3, and an insulating structure 4.
[0041] The heat sink 1 has a support surface 11. The substrate 2 includes a stacked insulating layer 21 and a conductive layer 22. The side of the insulating layer 21 facing away from the conductive layer 22 is connected to the support surface 11, creating an efficient heat dissipation channel for the power module. During the operation of the power module, the chip in the chip layer 3 generates a large amount of heat. This heat is conducted through the conductive layer 22 to the insulating layer 21, and then quickly transferred from the insulating layer 21 to the support surface 11 of the heat sink 1, where it is dissipated into the surrounding environment. Simultaneously, the insulating layer 21 in the substrate 2 electrically isolates the conductive layer 22 from the heat sink 1, preventing current leakage from the conductive layer 22 to the heat sink 1, thus ensuring the electrical safety of the power module during normal operation.
[0042] Chip layer 3 is disposed on the side of conductive layer 22 away from insulating layer 21 and is electrically connected to conductive layer 22. For example, in an inverter, chip layer 3 can convert direct current into alternating current.
[0043] The insulating structure 4 is disposed on the side of the insulating layer 21 facing the conductive layer 22 and located on the outer periphery of the conductive layer 22. In other words, the insulating structure 4 forms a physical isolation structure between the heat sink base 1 and the conductive layer 22 and occupies a certain space, making the originally relatively direct electrical connection path between the heat sink base 1 and the conductive layer 22 more tortuous, thereby increasing the creepage distance between the conductive layer 22 and the heat sink base 1. This can, to a certain extent, prevent breakdown leakage between the substrate 2 and the heat sink base 1, thus helping to improve the reliability of the power module.
[0044] In some embodiments, the heat sink 1 is made of a conductive material with a high thermal conductivity. For example, the heat sink 1 is made of materials such as copper, aluminum alloy, or graphite.
[0045] It should be noted that creepage distance refers to the shortest distance, measured along the insulating surface 41, between two conductive components (such as the conductive layer 22 and the heat sink 1 mentioned above) that can withstand the maximum voltage without breakdown under different operating conditions. There is a voltage difference between the two conductive components. When the voltage is high enough, current may flow along the insulating surface 41 from one component (conductive layer 22) to another component (heat sink 1). Sufficient creepage distance can prevent current leakage, flashover, or breakdown on the insulating surface 41, thereby avoiding electrical accidents and protecting the safety of personnel and equipment.
[0046] The insulating structure 4 is a closed ring structure, surrounding the conductive layer 22. In other words, the insulating structure 4 forms a complete isolation barrier around the conductive layer 22, effectively preventing accidental electrical connections between the conductive layer 22 and the heat sink 1 or other parts that may come into contact with the conductive layer 22, ensuring good electrical isolation between the conductive layer 22 and other components. Furthermore, during the installation, use, and maintenance of the power module, the conductive layer 22 may be damaged by external factors such as dust, moisture, and chemicals. The ring-shaped insulating structure 4 encloses the conductive layer 22, completely isolating it from surrounding components (such as the heat sink 1), reducing direct contact between the conductive layer 22 and the external environment, lowering the possibility of damage, and thus improving the reliability of the power module. ， This greatly reduces the risk of accidental conduction between the conductive layer 22 and other parts, with significant advantages, especially in high-voltage applications.
[0047] The insulating layer 21 has a first surface 211 away from the bearing surface 11, and both the conductive layer 22 and the insulating structure 4 are disposed on the first surface 211. By means of this arrangement, the conductive layer 22 and the insulating structure 4 are both disposed on the same first surface 211, ensuring that each manufacturing process is carried out according to the same standard, thus improving product consistency.
[0048] like Figure 3 As shown, in the thickness direction of the substrate 2, the insulating structure 4 has a first thickness T1 mm, and the conductive layer 22 has a second thickness T2 mm, where T1 > T2. That is, the insulating structure 4 has an insulating surface 41 that is far from the supporting surface 11, and the conductive layer 22 has a mounting surface 221 that is far from the supporting surface 11. The insulating surface 41 is further away from the supporting surface 11 than the mounting surface 221. When the height of the insulating structure 4 is greater than that of the conductive layer 22, it can provide a more comprehensive insulation effect for the conductive layer 22. In high-voltage applications, creepage distance is a key factor in ensuring insulation performance. The insulating surface 41 is further away from the supporting surface 11 than the mounting surface 221, meaning that the height of the insulating structure 4 is greater than that of the conductive layer 22, thereby increasing the creepage distance from the conductive layer 22 to the heat sink 1. The increased creepage distance makes it more difficult for current to leak along the surfaces of the insulating layer 21 and the insulating structure 4, which is beneficial for further improving the insulation performance of the power module.
[0049] For example, the height of the insulating structure 4 can also be higher than the height of the chip layer 3, providing additional insulation protection for the chip layer 3, preventing accidental electrical contact between the chip layer 3 and the external environment or other potentially energized parts, avoiding electrical faults such as short circuits, and ensuring the normal operation of the chip and the safety of the device.
[0050] The presence of the insulating layer 21 effectively isolates the conductive layer 22 from the heat sink base 1, preventing current from forming an unexpected conductive path through the heat dissipation path, thereby preventing short-circuit faults. Assume the insulating layer 21 has a second surface 212 facing the bearing surface 11, and a first distance X1 between the first surface 211 and the second surface 212. X1 ≥ 0.2 mm, ensuring the insulating layer 21 has a certain thickness, preventing a relatively thin insulating layer 21 from failing to provide sufficient insulation protection, and to a certain extent reducing the risk of the insulating layer 21 being broken down, ensuring the power module can operate safely under various operating conditions. Both the first surface 211 and the second surface 212 are flat surfaces. Furthermore, the first distance X1 ≤ 0.5 mm, preventing the insulating layer 21 from being too thick, increasing thermal resistance, and reducing heat dissipation efficiency. For example, the first spacing X1 can be any value among 0.2mm, 0.22mm, 0.25mm, 0.28mm, 0.30mm, 0.32mm, 0.35mm, 0.37mm, 0.40mm, 0.42mm, 0.45mm, 0.47mm or 0.5mm.
[0051] Please continue to refer to Figure 3 In the thickness direction of the substrate 2, the insulating structure 4 has a first thickness T1mm, and there is a first distance D1mm between the conductive layer 22 and the bearing surface 11, wherein T1≥1.5×D1. It should be noted that when the insulating structure 4 is not provided, the creepage distance between the conductive layer 22 and the bearing surface 11 is close to the first distance D1mm. Therefore, to a certain extent, the first distance D1mm can be interpreted as the creepage distance between the conductive layer 22 and the bearing surface 11 when the insulating structure 4 is not provided.
[0052] With the above configuration, the sufficient insulation thickness of the insulating structure 4 can better prevent electrical short circuits between the conductive layer 22 and the substrate 2 or other parts that may come into contact with the conductive layer 22, thereby improving the electrical safety and stability of the entire structure. For example, the first distance D1 between the conductive layer 22 and the bearing surface 11 is 2mm. According to the inequality T1≥1.5×D1, the first thickness T1 of the insulating structure 4 can be calculated to satisfy: T1≥1.5×2=3mm. That is, the thickness of the insulating structure 4 is at least 3mm. In actual design, a value greater than 3mm can be selected according to specific requirements, such as 3.5mm, 4mm, etc.
[0053] In some embodiments of this application, the power module further includes a thermally conductive connection layer 5, which is disposed on the second surface 212, that is, on the side of the insulating layer 21 facing the supporting surface 11, for connecting the insulating layer 21 and the supporting surface 11. The thermally conductive connection layer 5 can form a dedicated heat conduction channel, allowing the heat conducted from the insulating layer 21 to be transferred to the supporting surface 11 more efficiently. Compared to the case without the thermally conductive connection layer 5, it reduces the thermal resistance during heat conduction, allowing heat to be transferred more smoothly from the insulating layer 21 to the heat dissipation base 1 for dissipation.
[0054] For example, the connection between the insulating layer 21 and the heat sink base 1 (usually a metal material) reaches a molten or near-molten state, and then cools and solidifies to form a strong connection. For the ceramic insulating layer 21, special surface treatment may be required, such as coating it with a metal-weldable material (e.g., molybdenum-manganese layer, copper, etc.) to allow it to be welded to the heat sink base (e.g., copper or aluminum). Alternatively, a thermally conductive adhesive layer can be used to bond the insulating layer 21 and the heat sink base 1 together. The thermally conductive adhesive contains thermally conductive fillers, which can effectively transfer heat while ensuring a certain level of adhesion.
[0055] The power module also includes a packaging layer 6, which covers the insulating structure 4, chip layer 3, conductive layer 22, and insulating layer 21, extending to the carrier surface 11. This provides comprehensive physical protection for the insulating structure 4, chip layer 3, conductive layer 22, and insulating layer 21, preventing physical damage to the chip in chip layer 3, such as scratches on the chip surface, breakage of conductive layer 22, and wear of insulating layer 21, thereby improving the reliability and lifespan of the power module. Simultaneously, the packaging layer 6 prevents accidental electrical contact between the insulating structure 4, chip layer 3, and conductive layer 22 and other external components, avoiding short circuits and further enhancing the insulation performance of the power module. Furthermore, the packaging layer 6 covering the insulating structure 4 helps to further fix its position and enhances the overall insulation performance.
[0056] It is understandable that the encapsulation layer 6 can fill the tiny gaps between the chip layer 3, the conductive layer 22, the insulating layer 21 and the carrier surface 11, thereby reducing the thermal resistance caused by the air gap and improving the thermal conduction efficiency.
[0057] Multiple substrates 2 are spaced apart on the support surface 11. Each substrate 2 has a chip layer 3 on the side of its conductive layer 22 away from the insulating layer 21. Chips in adjacent chip layers 3 are electrically connected via connecting wires 7. This distributed arrangement of substrates 2 allows for relatively independent manufacturing and assembly of each substrate 2. Components such as the chip layer 3 and conductive layer 22 on each substrate 2 can be manufactured and tested separately before the substrate 2 is mounted onto the support surface 11. This improves production efficiency and facilitates the identification and resolution of manufacturing problems. For example, the chip layers 3 on each substrate 2 are at the same height, and at least one chip layer 3 includes multiple chips. These chips in the chip layer 3 can also be connected via connecting wires 7. These connecting wires 7 can be copper or gold wires.
[0058] It should be noted that the encapsulation layer 6 can simultaneously cover the conductive layer 22, the insulating layer 21, and the chip layer 3 disposed on each substrate 2. In other words, the above design can reduce the steps of individually encapsulating and assembling each substrate 2, simplifying the manufacturing process.
[0059] Please refer to Figure 4 The insulating layer 21 and the insulating structure 4 are integrated into a single unit, providing a more continuous and complete insulation barrier throughout the power module. The absence of seams or interfaces effectively prevents current leakage to the heat sink 1 through potential weak points, further improving the electrical isolation performance between the conductive layer 22 and the heat sink 1, and enhancing the overall insulation safety of the power module. Simultaneously, in manufacturing processes such as injection molding, a single, compliant integrated structure can be formed, resulting in more consistent electrical and physical properties across different products, thus improving overall product quality and reliability. For example, the insulating layer 21 and the insulating structure 4 can be integrally molded from ceramic material.
[0060] Please refer to Figure 2 and Figure 3 The insulating layer 21 and the insulating structure 4 are bonded together using a bonding adhesive. During manufacturing, the bonding adhesive serves as an auxiliary positioning method. When placing the insulating structure 4 onto the insulating layer 21, the adhesive's stickiness allows the insulating structure 4 to be accurately positioned in the predetermined location, facilitating operation and improving production efficiency. If the insulating layer 21 and the insulating structure 4 are made of different materials, the bonding adhesive can effectively combine them. This design allows for the selection of the most suitable material based on different functional requirements, while still meeting electrical performance requirements. For example, the insulating layer 21 may need high insulation and certain heat dissipation properties, while the insulating structure 4 may prioritize mechanical strength or specific creepage distance characteristics; the bonding adhesive can combine two materials with different properties.
[0061] In other words, in this embodiment, the adhesive itself possesses suitable insulating properties, ensuring insulation between the insulating layer 21 and the insulating structure 4 during bonding. Furthermore, the adhesive can fill any minute gaps that may exist between the insulating layer 21 and the insulating structure 4, preventing electrical faults such as current leakage. To a certain extent, if the adhesive has a uniform thickness and certain insulating properties, it can form a continuous insulating system together with the insulating layer 21 and the insulating structure 4, helping to further improve the creepage distance from the conductive layer 22 to the heat sink 1.
[0062] The insulation structure 4 is made of at least one of ceramics, glass, epoxy resin, and polytetrafluoroethylene. Therefore, it can be flexibly selected or combined according to the specific requirements of the power module (such as electrical performance, thermal performance, and mechanical performance requirements) to achieve optimal insulation, heat dissipation, and mechanical protection.
[0063] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.
[0064] The above description is merely a specific embodiment 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 technical scope 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 protection of the claims. Furthermore, specific examples have been used in the specification to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application, and the content of this specification should not be construed as a limitation of this application.
Claims
1. A power module, characterized in that, include: The heat dissipation base has a support surface; A substrate includes an insulating layer and a conductive layer stacked together, wherein the side of the insulating layer facing away from the conductive layer is connected to the bearing surface; A chip layer is disposed on the side of the conductive layer away from the insulating layer and is electrically connected to the conductive layer; An insulating structure is disposed on the side of the insulating layer facing the conductive layer and located on the outer periphery of the conductive layer.
2. The power module according to claim 1, characterized in that, The insulating structure is a closed ring structure and is arranged around the outer periphery of the conductive layer.
3. The power module according to claim 1 or 2, characterized in that, In the thickness direction of the substrate, the insulating structure has a first thickness T1 mm, and the conductive layer has a second thickness T2 mm, wherein T1 > T2.
4. The power module according to claim 1 or 2, characterized in that, In the thickness direction of the substrate, the insulating structure has a first thickness T1 mm, and there is a first distance D1 mm between the conductive layer and the bearing surface, wherein T1 ≥ 1.5 × D1.
5. The power module according to claim 1, characterized in that, The power module also includes: A thermally conductive connection layer is disposed on the side of the insulating layer facing the bearing surface, for connecting the insulating layer and the bearing surface.
6. The power module according to claim 1, characterized in that, Also includes: An encapsulation layer covers the insulating structure, the chip layer, the conductive layer, the insulating layer, and extends to the carrier surface.
7. The power module according to claim 1, characterized in that, The substrate has multiple substrates, and each substrate is spaced apart on the bearing surface. Each substrate has a chip layer on the side of its conductive layer away from the insulating layer. Chips in two adjacent chip layers are electrically connected by connecting wires.
8. The power module according to claim 1, characterized in that, The insulating layer and the insulating structure are an integral structure.
9. The power module according to claim 1, characterized in that, The insulating layer and the insulating structure are bonded together with adhesive.
10. The power module according to claim 1, 8, or 9, characterized in that, The insulating structure is made of at least one of ceramics, glass, epoxy resin, and polytetrafluoroethylene.