A power module with high reliability and high outflow capacity

Abstract

The utility model provides a kind of high reliability and high outflow capacity's power module.Power module includes at least one power unit, and the power unit is sequentially stacked along first direction radiator, copper clad ceramic substrate, silicon-based chip and connecting layer;Substrate is electrically connected with chip and is in thermal conduction with radiator, and chip is in thermal conduction with radiator by substrate;Connecting layer is electrically connected with chip, with conductivity and bondability, and is electrically connected with other components by connecting piece, so that chip is electrically connected with other components by connecting layer and connecting piece.The utility model transfers the high heating area of the upper surface bonding point of chip to the surface of connecting layer by connecting layer, avoids chip failure, realizes high outflow capacity and high reliability, and connecting layer is used as intermediate medium, to provide platform for subsequent refinement design.

Description

Technical Field

[0001] This utility model relates to the field of new energy vehicles, and in particular to a power module with high reliability and high output current capability. Background Technology

[0002] As a core component of the electric drive system in new energy vehicles, the performance of the power module directly affects the efficiency and reliability of the entire vehicle. A typical power unit, from bottom to top, includes a heat sink, an insulating substrate, and IGBT (Insulated Gate Bipolar Transistor) and FRD (Fast Recovery Diode) chips mounted on it. Bonding wires connect the chip electrodes to the substrate circuitry. This layered structure collectively undertakes the critical tasks of high-current switching and heat dissipation.

[0003] With advancements in semiconductor technology, the high-temperature tolerance of silicon-based power chips has significantly improved. However, the temperature bottleneck within the module has gradually shifted from the chip itself to its interconnect structure, particularly near the bonding points between traditional bonding wires and the chip. When large currents flow through the bonding wires, significant concentrated Joule heating is easily generated at this point. On the one hand, the high temperature at this location can easily trigger chip failure, limiting the outflow capacity. On the other hand, and more critically, the difference in thermal expansion coefficients between the bonding wires and the chip can induce alternating stress under drastic temperature changes, leading to bonding point fatigue, cracking, or even detachment, thereby damaging the chip. These multiple failure modes caused by localized overheating and thermomechanical stress have become key factors restricting the performance of silicon-based chips and limiting the overall outflow capacity of the module.

[0004] In summary, there are currently no power modules that can operate stably with a high current output. Utility Model Content

[0005] In order to overcome the above-mentioned technical defects, the purpose of this utility model is to provide a power module with high reliability and high output current capability.

[0006] This utility model discloses a power module with high reliability and high output current capability.

[0007] The power module includes at least one power unit; the at least one power unit includes a heat sink, a substrate, a chip and a connection layer stacked sequentially along a first direction; The substrate is a copper-clad ceramic substrate, which is electrically connected to the chip and conducts heat through the heat sink. The chip is a silicon-based chip, and heat is conducted through a substrate and a heat sink. The interconnect layer is electrically connected to the chip; the interconnect layer is conductive and bondable, and is electrically connected to other components through connectors; so that the chip can be electrically connected to other components through the interconnect layer and connectors.

[0008] Preferably, the material of the connecting layer includes at least one of tungsten copper alloy, molybdenum copper alloy, and aluminum-based silicon carbide composite material.

[0009] Preferably, the connection layer and the chip are fixedly connected by soldering with tin-based solder or lead-based solder.

[0010] Preferably, the connecting layer and the chip are fixedly connected by a sintering material, which includes at least one of silver sintering material and copper sintering material.

[0011] Preferably, the projection of the connecting layer in the first direction covers more than 50% of the area of ​​the chip; the shape of the connecting layer includes at least one of circular, square and elliptical shapes.

[0012] Preferably, the thickness of the connecting layer in the first direction is 0.05mm-2mm.

[0013] Preferably, the connector includes at least one of copper wire, aluminum strip, and copper strip.

[0014] Preferably, the power module includes multiple power units.

[0015] Preferably, the multiple connection layers corresponding to the multiple power units are integrally formed into a single structure; the connectors are integrated within the connection layers.

[0016] Preferably, it is a silicon-based insulated gate bipolar transistor power module or a silicon-based fast recovery diode power module.

[0017] Compared with existing technologies, the above technical solution has the following advantages: 1. By adding a conductive and bondable interconnect layer above the chip, the fundamental effect is to effectively transfer the high-heat-generating area, which is concentrated at the bonding points on the chip surface in traditional structures, to the surface of the interconnect layer. Since the interconnect layer itself does not involve the sensitive structures of the silicon-based chip, its localized overheating will not directly cause chip failure, thus achieving high current output capability and high reliability for the module. Furthermore, as an intermediate medium, the operating state of this interconnect layer does not affect the chip, providing a crucial platform for subsequent refined design (e.g., refined design of connectors). 2. By selecting specific materials such as tungsten copper alloy, molybdenum copper alloy, or aluminum-based silicon carbide composite materials to fabricate the interconnect layer, it is possible to ensure that the interconnect layer has certain electrical conductivity and bonding properties. Furthermore, it also possesses a certain thermal conductivity, facilitating heat transfer while matching the coefficient of thermal expansion with the chip, significantly reducing thermal stress generated at the interface due to temperature cycling. This dual advantage significantly suppresses the failure risk of the interconnect layer itself and its interface with the chip and connectors, ensuring structural stability under high current. Moreover, by rationally setting the surface area, shape, and thickness of the interconnect layer, the heat dissipation efficiency of the interconnect layer on the chip can be optimized, while controlling cost and the overall size of the power module. 3. Furthermore, due to the isolation effect of the connection layer, copper connectors (such as copper wires or copper strips) can be used to enhance conductivity without considering the damage to the chip caused by thermal expansion of the copper wires, thereby significantly reducing connection losses and improving current carrying capacity. Alternatively, aluminum connectors can be used to reduce costs. The design of integrating multiple power units increases the power density of the module. Furthermore, integrating the connection layer of multiple power units into a single structure and optimizing the placement of connectors (such as copper strips) not only simplifies electrical interconnection, reduces parasitic parameters, and improves current balance, but more importantly, it fundamentally reduces the number of independent interconnection points, effectively eliminating the failure risk of traditional bonding points, a weak link, and greatly enhancing the overall structural robustness and long-term operational reliability of the module. 4. This solution is particularly suitable for power modules composed of silicon-based insulated-gate bipolar transistors (IGBTs) and fast recovery diodes. These modules are the core of the electric drive system in new energy vehicles, operating under high-frequency switching and high-current conditions, and are extremely sensitive to the electrothermal stress of the interconnect structure. The connection layer structure and its corresponding optimization measures provided in this solution successfully solve the common bottleneck problem of bonding point failure in such silicon-based power modules, fully releasing the temperature resistance potential of silicon-based chips, and ultimately meeting the core requirements of new energy vehicles for high current output capacity, high reliability, and compactness of power modules. Attached Figure Description

[0018] Figure 1 A schematic diagram of the structure of a power unit of the high-reliability and high-current-capacity power module provided in this application; Figure 2 A schematic diagram showing the connection relationship between two power units of the high-reliability and high-current-capacity power module provided in this application.

[0019] Figure reference numerals: 100, power unit; 1. Radiator; 2. Substrate; 3. Chips; 4. Connecting layer; 41. Connecting parts; z, First direction. Detailed Implementation

[0020] The advantages of this utility model are further illustrated below with reference to the accompanying drawings and specific embodiments.

[0021] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0022] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0023] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if," as used herein, can be interpreted as "when," "in response to determination," or "when," or "in the event of a determination." In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "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 utility model 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 utility model.

[0024] In the description of this utility model, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0025] In the following description, the use of suffixes such as "module," "part," or "unit" to denote elements is solely for the purpose of illustrating this invention and has no specific meaning in itself. Therefore, "module" and "part" can be used interchangeably.

[0026] Please see Figure 1 , Figure 1 A schematic diagram of the structure of a power unit of the high-reliability and high-current-capacity power module provided in this application.

[0027] like Figure 1 As shown, this utility model provides a power module with high reliability and high output current capability. The power module includes at least one power unit 100; the at least one power unit 100 includes a heat sink 1, a substrate 2, a chip 3 and a connection layer 4 stacked sequentially along a first direction z. Among them, the substrate 2 is a copper-clad ceramic substrate, which is electrically connected to the chip 3 and conducts heat to the heat sink 1. Chip 3 is a silicon-based chip, and heat is conducted between the substrate 2 and the heat sink 1. The connection layer 4 is electrically connected to the chip 3; the connection layer 4 is conductive and bondable, and is electrically connected to other components through the connector 41; so that the chip 3 can be electrically connected to other components through the connection layer 4 and the connector 41.

[0028] By adding a conductive and bondable connection layer 4 above chip 3, the fundamental effect is to effectively transfer the high-heat-generating area concentrated at the bonding points on the upper surface of chip 3 in the traditional structure to the surface of connection layer 4. Since connection layer 4 itself does not involve the sensitive structures of the silicon-based chip 3, its localized overheating will not directly cause chip 3 failure, thus achieving high outflow capacity and high reliability of the module. Furthermore, as an intermediate medium, the working state of connection layer 4 does not affect chip 3, providing a crucial platform for subsequent refined design (e.g., refined design of connector 41).

[0029] The above is an explanation of the basic concept of this application. The specific embodiments of this application will be further described below with reference to the accompanying drawings.

[0030] As mentioned earlier, the thermal conductivity of the connection layer 4 can be further improved through further design.

[0031] Therefore, it is understandable that, firstly, the specific material of the connecting layer 4 is not limited.

[0032] In one possible implementation, the material of the connecting layer 4 includes at least one of tungsten copper alloy, molybdenum copper alloy, and aluminum-based silicon carbide composite material.

[0033] By selecting specific materials such as tungsten copper alloy, molybdenum copper alloy, or aluminum-based silicon carbide composite material to fabricate the bonding layer 4, a certain degree of conductivity and bonding capability can be ensured. Furthermore, it possesses a certain thermal conductivity, facilitating heat transfer, while its coefficient of thermal expansion matches that of the chip 3, significantly reducing thermal stress generated at the interface due to temperature cycling. This dual advantage significantly suppresses the failure risk of the bonding layer 4 itself and its interface with the chip 3 and connector 41, ensuring structural stability under high current.

[0034] In another possible implementation, the material of the connection layer 4 can also be other than the materials mentioned above. Those skilled in the art can freely choose according to their needs and the characteristics of chip 3, and this application does not impose any restrictions.

[0035] Secondly, the fixing method between the connection layer 4 and the chip 3 is also not limited.

[0036] In one possible implementation, the connection layer 4 and the chip 3 are fixedly connected by soldering with tin-based solder or lead-based solder.

[0037] In another possible implementation, the connection layer 4 and the chip 3 are fixedly connected by a sintering material, which includes at least one of silver sintering material and copper sintering material.

[0038] Those skilled in the art will understand that the same methods can be applied to the connection relationships between other components. For example, chip 3 and substrate 2, substrate 2 and heat sink 1, etc., can also be connected by the welding or sintering methods described above.

[0039] Furthermore, the shape and size of the connecting layer 4 are also unlimited.

[0040] In one possible implementation, the projection of the connection layer 4 in the first direction z covers more than 50% of the area of ​​the chip 3; the shape of the connection layer 4 includes at least one of the following: circular, square, and elliptical.

[0041] By limiting the area of ​​the projection of the connection layer 4 covering the surface of the chip 3, the area available for heat exchange between the two can be increased. The larger contact area directly reduces the local density of current transmission and the interfacial contact resistance, reducing Joule heating at the source. At the same time, it significantly improves the efficiency of heat diffusion from the chip 3 to the connection layer 4, avoiding excessive heat concentration at the edges or center of the chip 3. Setting the connection layer 4 to a regular shape such as a circle, square, or ellipse helps to optimize the uniformity of current distribution and heat flow path, avoiding electric or thermal field distortion caused by sharp corners, and further improving heat dissipation reliability and current uniformity.

[0042] Furthermore, the thickness of the connecting layer 4 in the first direction z is 0.05mm-2mm.

[0043] By appropriately setting the thickness, on the one hand, it avoids the situation where the connection layer 4 is too thick, leading to excessive cost and an increase in the overall size of the power module. On the other hand, it also avoids the situation where the connection layer 4 is too thin, resulting in poor heat dissipation and easy deformation when heated. Therefore, by precisely designing the thickness, the connection layer 4 can be guaranteed to have both efficient heat dissipation and long-term structural integrity when carrying high current.

[0044] The above is a detailed description of the specific implementation of the connection layer 4. Those skilled in the art will understand that the specific material of the connector 41 is also not limited.

[0045] Please see Figure 2 , Figure 2 A schematic diagram showing the connection relationship between two power units of the high-reliability and high-current-capacity power module provided in this application.

[0046] like Figure 2 As shown, and in combination Figure 1 This is understood. In one possible implementation, connector 41 is a connector that includes copper wire, aluminum strip, or copper strip.

[0047] The principle needs to be explained here: In existing technology, connector 41 is often directly connected to the top of chip 3. Therefore, in terms of material selection, connector 41 is often made of aluminum. This is because aluminum connector 41 is less likely to damage chip 3 when subjected to heat deformation. However, aluminum connector 41 has lower conductivity and weaker current carrying capacity.

[0048] Therefore, due to the presence of the connection layer 4 in this application, thermal stress can be isolated from the chip 3, allowing for the safe use of highly conductive copper wires. Furthermore, because the connection layer 4 has a larger area available for electrical connections, copper / aluminum strips with even higher current-carrying capacity can be further applied. This not only significantly reduces the resistance loss and heat generation of the connector 41 itself, but also greatly improves current transmission efficiency, directly enhancing the overall current-carrying capacity of the module, especially suitable for the instantaneous high-current operating conditions of new energy vehicles.

[0049] Of course, in another possible implementation, the connector 41 can also be made of aluminum strip to accommodate certain special settings. Those skilled in the art can design it as needed, and this application does not impose any restrictions on it.

[0050] The above is a description of the connector 41 provided in this application. The overall structure of the power module will be described below.

[0051] Those skilled in the art will understand that the number of power units 100 specifically included in the power module is not limited.

[0052] like Figure 2As shown, in one possible implementation, the power module includes multiple power units 100. By employing the aforementioned structure in each power unit 100, heat can be efficiently dissipated within the unit. This modular design allows for power expansion without sacrificing unit-level heat dissipation efficiency. Even when multiple units work together, a uniform temperature distribution can be maintained, preventing localized overheating from becoming a system bottleneck. This enables the power module to continuously and stably output a large current in high-power applications such as new energy vehicles.

[0053] Furthermore, the multiple connection layers 4 corresponding to the multiple power units 100 are integrally formed into a single structure; the connector 41 is integrated within the connection layer 4.

[0054] The integrated connection layer 4 simplifies the number of parts and reduces production and processing costs. Embedding or integrating the connector 41 (such as a copper strip) into this integrated structure can shorten the current path, enhance mechanical stability, and effectively increase the heat dissipation surface area.

[0055] By further integrating the connector 41 into the connection layer 4, the power module can be connected directly through the connection layer 4 instead of the connector 41. On the one hand, this can further reduce the number of connection points, fundamentally reduce the probability of traditional bond wire failure modes, and significantly improve the overall reliability and power density of the module. On the other hand, the volume available for connection is also greatly increased, thereby greatly enhancing the current conduction capacity and further improving the output current capacity of the power module.

[0056] It should be noted that the type of power module applicable to this application is not limited. For example, the power module can be a silicon-based insulated gate bipolar transistor (IGBT) power module or a silicon-based fast recovery diode (FRD) power module.

[0057] To enable those skilled in the art to more clearly and intuitively understand the technical effects of the solution provided in this application, an embodiment is provided below for reference.

[0058] In one possible embodiment, the power module was set to the following conditions during the conduction loss test: junction temperature Tvj = 185 °C; IGBT collector current Ice / FRD forward current If = 450 A. The final result was: IGBT saturation voltage drop Vcesat = 1.50 V. In comparison, the test result under the same conditions in the prior art is 1.63 V. The FRD forward conduction voltage drop FRDVF is 1.70 V, compared to 1.91 V in the prior art. It can be seen that the conduction loss is significantly reduced.

[0059] In the stability test, the power module's input DC voltage Vdc = 480V; switching frequency fsw = 10kHz; coolant flow rate Frate = 8L / min; coolant temperature Tcoolant = 85℃; power factor PF = 0; and output AC frequency fac = 50Hz. The final result was that the power module's maximum output current Ioutput reached 550A without failure. Under the same conditions, existing solutions failed at 430A. This demonstrates a significant increase in output current capacity and high reliability.

[0060] In summary, the power module provided in this application has high reliability and high output current capability.

[0061] It should be noted that the embodiments of this utility model have better implementability and are not intended to limit this utility model in any way. Any person skilled in the art may use the above-disclosed technical content to change or modify it into equivalent effective embodiments. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical essence of this utility model without departing from the content of the technical solution of this utility model shall still fall within the scope of the technical solution of this utility model.

Claims

1. A power module with high reliability and high current output capability, characterized in that, The power module includes at least one power unit; the at least one power unit includes a heat sink, a substrate, a chip, and a connection layer stacked sequentially along a first direction; The substrate is a copper-clad ceramic substrate, which is electrically connected to the chip and conducts heat with the heat sink; The chip is a silicon-based chip, and heat is conducted between the substrate and the heat sink. The connection layer is electrically connected to the chip; the connection layer is conductive and bondable, and is electrically connected to other components through connectors; so that the chip can be electrically connected to other components through the connection layer and the connectors.

2. The power module as described in claim 1, characterized in that, The material of the connecting layer includes at least one of tungsten copper alloy, molybdenum copper alloy, and aluminum-based silicon carbide composite material.

3. The power module as described in claim 2, characterized in that, The connection layer and the chip are fixedly connected by soldering with tin-based solder or lead-based solder.

4. The power module as described in claim 2, characterized in that, The connecting layer and the chip are fixedly connected by a sintering material, which includes at least one of silver sintering material and copper sintering material.

5. The power module as described in claim 1, characterized in that, The projection of the connection layer in the first direction covers more than 50% of the area of ​​the chip; and the shape of the connection layer includes at least one of the following: circular, square, and elliptical.

6. The power module as described in claim 1, characterized in that, The thickness of the connecting layer in the first direction is 0.05mm-2mm.

7. The power module as described in claim 1, characterized in that, The connector includes at least one of copper wire, aluminum strip, and copper strip.

8. The power module as described in claim 1, characterized in that, The power module includes multiple power units.

9. The power module as described in claim 8, characterized in that, The multiple connection layers corresponding to the multiple power units are integrally formed structures; the connectors are integrated within the connection layers.

10. The power module as described in any one of claims 1-9, characterized in that, The power module is a silicon-based insulated gate bipolar transistor power module or a silicon-based fast recovery diode power module.

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