Enclosed waterway single-parallel integrated power semiconductor module

Abstract

The application belongs to the technical field of new energy automobile power electronic control, and particularly relates to a closed water channel single-parallel integrated power semiconductor module, which comprises six TPAK power units arranged in a single row and symmetrically along the length direction of a cold plate; three upper pipe TPAK power units and three lower pipe TPAK power units are alternately and symmetrically arranged to form a three-phase full bridge; a folded fin is arranged between the cold plate and a water channel plate, and the two sides of the folded fin are respectively connected with the inner surface of the cold plate and the inner surface of the water channel plate through vacuum brazing to form a closed water channel; the lower surface of a ceramic substrate of the TPAK power unit is connected with the upper surface of the cold plate through vacuum reflow soldering to form a continuous metal bonding layer; an independent temperature measuring plate is arranged above the top plastic package shell of the TPAK power unit, and the sensing surface of a temperature sensing element is elastically contacted with the surface of the top plastic package shell of the TPAK power unit through heat-conducting glue, so that a vehicle-grade integrated power brick structure without a flexible thermal interface material, a sealing ring and a fastener compression is realized.

Description

Technical Field

[0001] This invention belongs to the field of power electronic control technology for new energy vehicles, specifically involving a closed-channel single-parallel integrated power semiconductor module. This module is suitable for high-voltage power conversion scenarios such as motor controllers, range extenders, and water pump controllers in new energy vehicles. Background Technology

[0002] In high-voltage power conversion systems such as motor controllers and range extender controllers in new energy vehicles, power semiconductor devices such as IGBTs and SiC MOSFETs are the core heat sources, and their heat dissipation performance directly determines the power density, reliability, and lifespan of the controller. Meanwhile, four key technical indicators—current balancing between parallel chips, interface thermal resistance between the module and the cold plate, sealing reliability of the cold plate water channels, and real-time monitoring of the junction temperature of power devices—collectively constitute the core constraints of power semiconductor module structural design.

[0003] Currently, mainstream power semiconductor module heat dissipation and interconnection solutions can be broadly categorized into three types. The first type is the discrete device plus water-cooled plate solution, where power devices dissipate heat by attaching to the water-cooled plate using flexible thermal interface materials such as thermal grease or thermal pads. In this solution, the thermal conductivity of the thermal grease is typically only at the level of 3W / m·K to 6W / m·K, far lower than that of metal materials, resulting in significant interfacial thermal resistance. Furthermore, the thermal grease is prone to aging, drying, and migration under high-temperature conditions, leading to poor long-term reliability. Simultaneously, the dispersed device layout occupies a large space, making it difficult to meet the requirements of high-power-density controllers. The second type is the traditional integrated power module solution, employing a multi-chip parallel packaging structure, such as half-bridge modules (2-in-1) and full-bridge modules (6-in-1). Multiple IGBT or SiC MOSFET chips are integrated onto a DBC or AMB substrate and then connected to the water-cooled plate via bolts and thermal interface materials. While this solution improves device integration, it still suffers from current sharing errors due to inconsistent current path lengths between parallel chips, as well as issues with interface thermal resistance and silicone grease aging between the DBC substrate and the water-cooled plate. The third type is the open-channel solution. Traditional water-cooled plates often feature an open-channel structure with straight-fin heat dissipation fins, resulting in limited heat exchange area and insufficient fluid turbulence. Furthermore, the water channel seal relies on mechanical seals with rubber sealing rings, which are prone to seal failure and coolant leakage under vehicle vibration and temperature cycling conditions, leading to short-circuit faults within the controller.

[0004] In recent years, with the large-scale application of silicon carbide power devices in the electric drive systems of new energy vehicles, some advanced solutions have adopted a single-tube, single-row packaging structure (such as TPAK packaging) combined with silver-sintered heat sinks and laser-welded copper busbars. While this single-chip, single-row packaging simplifies the module structure and improves power cycle reliability to some extent, it still has the following shortcomings: the heat sink generally uses a pin-fin structure, and the water channel sealing still partially relies on mechanical seals; temperature monitoring still uses a DBC substrate-embedded NTC solution, which can only obtain single-point temperature information and is difficult to reflect the current sharing differences and local overheating distribution between the upper and lower tubes of the three-phase bridge arm; the number of parallel chips is relatively large (each phase bridge arm typically uses 4 parallel chips), making it difficult to ensure completely consistent current path lengths, resulting in current sharing errors. Furthermore, the multiple welding, sintering, and mechanical pressing processes are dispersed, making the assembly process complex and difficult to achieve integrated one-time molding.

[0005] See Figure 1 The image shows a prior art solution involving discrete components and a water-cooled plate. (See also...) Figure 2 The image shows a conventional integrated power module solution in the prior art. See also... Figure 3 The figure shows an open waterway structure in the prior art.

[0006] In summary, existing power semiconductor module technology suffers from the following core technical defects: First, layout defects: the inconsistent current path lengths in traditional multi-chip parallel layouts lead to uneven current distribution among parallel chips, causing localized overheating and limiting the module's maximum output current and reliability. Furthermore, the dispersed layout results in a large controller size, hindering power density improvement. Second, heat dissipation defects: traditional straight-fin water channels have limited heat exchange area and insufficient fluid turbulence, resulting in low heat dissipation efficiency. Open water channels rely on mechanical seals, which are prone to seal failure and coolant leakage under vehicle vibration and temperature cycling conditions. Third, connection defects: traditional power modules are connected to water-cooled plates using bolts and thermal grease, resulting in high interfacial thermal resistance. The grease is also prone to aging and drying at high temperatures, leading to poor long-term reliability. Traditional water channel plates and the cooling plate body often use bolt-sealed structures, resulting in complex assembly processes and poor consistency. Fourth, temperature measurement deficiencies: Traditional DBC substrates with built-in NTC solutions can only collect approximate temperatures at single points, making it difficult to reflect the independent temperature distribution of the upper and lower transistors in each phase bridge arm, and thus unable to accurately locate current sharing differences and localized overheating. Fifth, integration deficiencies: In traditional solutions, power devices, drive circuits, and heat dissipation structures are distributed, resulting in complex internal wiring in the controller, large parasitic inductance, poor electromagnetic compatibility performance, numerous assembly steps, and high production costs. Summary of the Invention

[0007] To address the aforementioned shortcomings of existing technologies, this invention aims to solve the following core technical problems. First, it solves the problems of uneven current distribution and high parasitic inductance in traditional power module parallel chip connections by using a precise mapping layout of single transistors corresponding to single bridge arms, achieving equal current path lengths from each power terminal to the bus capacitor, thus improving module current sharing and switching performance. Second, it solves the problems of low heat dissipation efficiency and poor sealing reliability of traditional water-cooled plates by employing a closed water channel and folded fin structure. The folded fins themselves absorb the thermal expansion difference between the cold plate and the water channel plate and enhance convective heat transfer, improving heat transfer efficiency and eliminating the risk of leakage. Third, it solves the problems of high thermal resistance and poor long-term reliability at the interface between the traditional module and the cold plate by using a vacuum reflow soldering process to achieve a metal bonding connection between the ceramic substrate and the cold plate, eliminating the interface thermal resistance and aging problems caused by flexible thermal interface materials. Fourth, it solves the problems of traditional water channel sealing relying on sealing rings and complex assembly processes by using a two-sided vacuum brazing integral welding seal for the folded fins, base plate, and cold plate, improving structural reliability and integration. Fifth, it solves the problem of low-dimensional single-point temperature measurement information in traditional DBC built-in NTC. Through the structure of top independent temperature measuring plate with elastic pressing and thermal conductive adhesive, it realizes independent acquisition of the shell temperature of each phase upper and lower tube TPAK power unit, providing phase-by-phase and tube-by-tube temperature field information.

[0008] To address the aforementioned technical problems, this invention provides a closed-channel single-parallel integrated power semiconductor module, comprising six TPAK power units symmetrically arranged in a single row along the length of a cold plate. Three upper-tube TPAK power units and three lower-tube TPAK power units are alternately and symmetrically arranged to form a three-phase full bridge. Folded fins are disposed between the cold plate and the channel plate, with both sides of the folded fins vacuum brazed to the inner surfaces of the cold plate and the channel plate, respectively, to form a closed channel. The lower surface of the ceramic substrate of the TPAK power unit is vacuum reflow soldered to the upper surface of the cold plate to form a continuous metal bonding layer. An independent temperature measuring plate is disposed above the top plastic-encapsulated shell of the TPAK power unit, and a temperature sensing element is provided on the independent temperature measuring plate. The sensing surface of the temperature sensing element is in elastic contact with the surface of the top plastic-encapsulated shell of the TPAK power unit via thermally conductive adhesive.

[0009] As a preferred embodiment, each of the six TPAK power units contains a single SiC MOSFET chip or a single IGBT chip, and each TPAK power unit independently constitutes one arm of a three-phase full-bridge topology, so that the current path length from the power terminal of each TPAK power unit to the bus capacitor is equal to that of each other.

[0010] As a preferred embodiment, there is no flexible thermally conductive interface material between the lower surface of the ceramic substrate of the TPAK power unit and the upper surface of the cold plate; the continuous metal bonding layer formed by vacuum reflow soldering directly connects the ceramic substrate and the cold plate.

[0011] As a preferred embodiment, the folded fins are thin-walled corrugated structures, which have elastic deformation capabilities along the thickness direction of the cold plate to accommodate the thermal expansion difference between the cold plate and the water channel plate; the folded fins are continuously arranged along the coolant flow direction to form multiple bent heat exchange channels.

[0012] As a preferred embodiment, the welding is completed in two steps. In the first step, the brazing interfaces between the folded fins and the inner surface of the cold plate, the inner surface of the cold plate and the mounting surface of the water channel plate, and the brazing interfaces between the folded fins and the inner surface of the water channel plate are completed in a vacuum brazing process. In the second step, the reflow soldering interface between the lower surface of the ceramic substrate and the upper surface of the cold plate is completed in a vacuum reflow soldering process.

[0013] As a preferred embodiment, six temperature measuring points are arranged one by one along the single-row arrangement direction of the six TPAK power units on the independent temperature measuring plate, and each temperature measuring point independently collects the surface temperature of the plastic-encapsulated shell of the corresponding TPAK power unit.

[0014] As a preferred embodiment, the independent temperature measuring plate is positioned by a positioning pin and locked to the plastic body of the positive and negative welding copper busbar assembly by a self-tapping screw; the plastic body of the positive and negative welding copper busbar assembly is provided with an elastic structure for pressing the temperature sensing element.

[0015] As a preferred embodiment, it also includes a bus capacitor, a three-phase welded copper busbar, and a positive and negative welded copper busbar assembly; the bus capacitor, the three-phase welded copper busbar, the positive and negative welded copper busbar assembly, and the six TPAK power units are connected by laser welding.

[0016] The present invention achieves the following significant technical effects through the above technical solution.

[0017] Firstly, current sharing and electrical performance are improved. The six TPAK power units are arranged symmetrically in a single row, so that each TPAK power unit independently forms one arm of a three-phase full bridge. The current path length from each TPAK power unit to the bus capacitor is completely consistent, fundamentally eliminating the problem of uneven current distribution in multi-chip parallel layouts, and controlling the current sharing error within 5%. At the same time, the bus capacitor, three-phase welded copper busbar, and positive and negative welded copper busbar assemblies are interconnected by laser welding to form the shortest current loop. The parasitic inductance of the bus is reduced by more than 40% compared to the multi-tube parallel scheme, the switching loss is reduced by about 20%, and the electromagnetic compatibility performance is significantly optimized.

[0018] Secondly, heat dissipation performance is significantly improved. The thin-walled corrugated structure of the folded fins allows the fluid boundary layer to redevelop at each bend, increasing the convective heat transfer coefficient by more than 30% compared to the traditional straight-fin structure. At the same time, the continuous metal bonding layer formed by vacuum reflow soldering between the ceramic substrate and the cold plate replaces the thermal grease, reducing the interface thermal resistance by more than 80% compared to the grease solution. The overall heat dissipation capacity of the module is increased by more than 50%, supporting high power density designs with a power density exceeding 100 kW / L.

[0019] Third, the sealing reliability is comprehensively improved. The vacuum brazing between the cold plate and the water channel plate forms a fully welded metal sealing structure, completely eliminating the long-term weak point of the sealing ring and fundamentally eliminating the risk of coolant leakage; at the same time, the structure without thermal grease avoids the aging and failure of thermal grease, and the life cycle reliability of the module under automotive-grade temperature cycling and vibration shock conditions is improved by more than 10 times, meeting the relevant requirements of automotive-grade AEC-Q100 and ISO 26262 standards.

[0020] Fourth, the ability to sense temperature fields by phase and pipe emerges. The independent temperature measuring plate is arranged with six temperature measuring points corresponding to each of the six TPAK power units in a single row. The shell surface temperature of each phase upper and lower TPAK power unit is independently collected through a contact method of elastic pressing and thermally conductive adhesive. This upgrades the approximate temperature data of the traditional single-point NTC to six-point temperature field distribution data by phase and pipe, which can accurately reflect the differences in flow uniformity, local overheating and temperature imbalance, and provide higher-dimensional temperature field information for the vehicle thermal management system.

[0021] Fifth, process compression and integration improvement. The module has no bolt connections, no sealant, and no thermal grease, forming an integrated power brick structure. Assembly process and production costs are significantly reduced. The modular design facilitates standardized production and maintenance, and can be adapted to various new energy vehicle power conversion scenarios such as motor controllers, range extenders, and water pump controllers of different power levels.

[0022] Sixth, the synergistic effect of the causal chain. There is a synergistic relationship of causal progression among the various technical features of this invention. The precise mapping of a single tube to a single bridge arm reduces the effective size of each ceramic substrate, providing the geometric prerequisite for eliminating flexible thermal interface materials and directly adopting vacuum reflow soldering. The thermal expansion difference between the cold plate and the water channel plate is absorbed by the thin-walled corrugated elastic deformation of the folded fins, which also enhance convective heat transfer. The two solder surfaces and three locations are welded in the same vacuum brazing process through a shared solder temperature window, allowing the overall structure to be formed in one step. Because the ceramic substrate becomes the solder interface, it cannot be compatible with the built-in NTC solution; instead, the temperature monitoring is reconstructed into an independent top temperature measuring plate, obtaining phase-by-phase and tube-by-tube temperature field information in reverse. The combined relationship of the above features is indivisible and irreplaceable, forming a paradigm-level innovation in power semiconductor module structure. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the existing technology for discrete components with water-cooled plates.

[0024] Figure 2 This is a structural diagram of a traditional integrated power module solution in the existing technology.

[0025] Figure 3 This is a schematic diagram of an open waterway structure in existing technology.

[0026] Figure 4 This is a power brick module layout diagram of the closed-channel single-parallel integrated power semiconductor module in Embodiment 1 of the present invention.

[0027] Figure 5 This is an exploded view of the structure of the closed-channel single-parallel integrated power semiconductor module of the present invention.

[0028] Figure 6 This is a schematic diagram of the overall layout of the closed-channel single-parallel integrated power semiconductor module without PCBA in Embodiment 1 of the present invention.

[0029] Figure 7 This is an exploded view of the overall structure of the enclosed waterway single-parallel integrated power semiconductor module including PCBA in Embodiment 1 of the present invention.

[0030] Figure 8 This is a schematic diagram of the independent temperature measuring plate fixing structure in Embodiment 1 of the present invention.

[0031] Figure 9 This is a cross-sectional schematic diagram of the thermocouple pressing structure in Embodiment 1 of the present invention.

[0032] The diagram is labeled as follows: 1-TPAK power unit; 2-FR4 insulation board; 3-cold plate; 4-folded fins; 5-channel plate; 6-three-phase welded copper busbar; 7-positive and negative welded copper busbar assembly; 8-independent temperature measuring plate; 9-TPAK power unit top plastic-encapsulated shell; 10-temperature sensing element; 11-thermal conductive adhesive; 12-bus capacitor; 13-self-tapping screw; 14-hexagonal stud; 15-drive control PCBA; 16-M5*16; 101-closed channel single-parallel integrated power semiconductor module; 102-three-phase welded copper busbar and TPAK laser weld joint. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the specific embodiments of this invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Those skilled in the art, under the guidance of this invention, can make conventional equivalent substitutions for some structural features, and all such equivalent substitutions fall within the protection scope of this invention.

[0034] Example 1. (As shown in the original text) Figures 4 to 8 As shown, this embodiment provides a closed-channel single-parallel integrated power semiconductor module 101, mainly comprising: six TPAK power units 1 arranged symmetrically in a single row along the length of a cold plate 3; an FR4 insulating plate 2 disposed above the TPAK power units 1; a cold plate 3 located below the six TPAK power units 1; folded fins 4 disposed inside the cold plate 3; a channel plate 5 located below the folded fins 4; a three-phase welding copper busbar 6 and a positive and negative welding copper busbar assembly 7 connected to the six TPAK power units 1 by laser welding; an independent temperature measuring plate 8 disposed above the top plastic-encapsulated shell 9 of the TPAK power units 1; a temperature sensing element 10 integrated on the independent temperature measuring plate 8; thermally conductive adhesive 11 coated between the sensing surface of the temperature sensing element 10 and the top plastic-encapsulated shell 9 of the TPAK power units 1; a bus capacitor 12 laser-welded to the positive and negative welding copper busbar assembly 7; and self-tapping screws 13 for fixing the independent temperature measuring plate 8. All the above components are integrated according to the connection and positional relationships described below, together constituting the closed-channel single-parallel integrated power semiconductor module.

[0035] The specific arrangement and connection relationship of the six TPAK power units 1 are detailed below. The six TPAK power units 1 are arranged symmetrically in a single row along the length of the cold plate 3; each of the six TPAK power units 1 includes three upper TPAK power units and three lower TPAK power units; the three upper TPAK power units and the three lower TPAK power units are arranged alternately and symmetrically, forming a topology sequence of phase A upper MOSFET, phase A lower MOSFET, phase B upper MOSFET, phase B lower MOSFET, phase C upper MOSFET, and phase C lower MOSFET, thereby constituting a three-phase full-bridge topology. Each TPAK power unit 1 integrates a single SiC MOSFET chip or a single IGBT chip; the chip is bonded to the ceramic substrate inside the TPAK power unit 1 through a silver sintering layer to form a modular power unit; the TPAK power unit 1 has a plastic package structure with dimensions of approximately 20 mm x 28 mm x 4 mm, and includes gate, source, and drain power terminals located at one end. The power terminals of the six TPAK power units 1 are all arranged facing the same side along the length of the cold plate 3. The current path lengths from the power terminals of each TPAK power unit 1 to the bus capacitor 12 and the three-phase welded copper busbar 6 are equal, thus eliminating the inherent current path length differences in multi-chip parallel structures. Since each TPAK power unit 1 independently constitutes one arm of a three-phase full-bridge topology, there is no multi-chip parallel structure, fundamentally eliminating the current sharing error between parallel chips and keeping the overall current distribution current sharing error within 5%. Simultaneously, the single-row arrangement is compact, occupying little lateral space, and the overall power module power density can exceed 100 kW / L. The TPAK power unit 1 adopts a modular design, allowing for independent electrical testing and screening, facilitating production and maintenance, and allowing the selection of different SiC MOSFET or IGBT chips on the same platform according to different power level requirements.

[0036] The specific connection and positional relationships of the cold plate 3, folded fins 4, and water channel plate 5 are detailed below. The cold plate 3 is generally long and plate-shaped, with six stepped surfaces arranged along its length for mounting the TPAK power unit 1. The lower surface of the water channel plate 5 has a cavity structure to accommodate the folded fins 4, and the lower side of the cold plate 3 is closed by the water channel plate 5 to form a closed water channel. The water channel plate 5 is a long plate-shaped structure corresponding to the shape of the cold plate 3, and the upper surface of the water channel plate 5 is aligned with the lower edge of the cavity of the cold plate 3. Both the cold plate 3 and the water channel plate 5 are preferably made of aluminum alloy. The folded fins 4 are disposed in the cavity between the cold plate 3 and the water channel plate 5. The folded fins 4 are formed by stamping and folding thin aluminum alloy foil to form a continuous corrugated structure. The height of each corrugated unit is equal to the internal clearance dimension of the cavity of the cold plate 3. The crests face the inner surface of the cold plate 3, and the troughs face the inner surface of the water channel plate 5. They are continuously arranged along the coolant flow direction to form multiple bent heat exchange channels. The two sides of the folded fins 4 are vacuum brazed to the inner surfaces of the cold plate 3 and the water channel plate 5, respectively. The inner surface of the cold plate 3 is also vacuum brazed to the mounting surface on the water channel plate 5. The brazing is performed using Al-Si brazing filler metal to form a continuous weld. This continuous weld serves both as a structural welding connection and as a water channel seal, making the cold plate 3, folded fins 4, and water channel plate 5 an integrated closed water channel structure, completely eliminating the rubber sealing ring between the cold plate and the water channel plate in traditional solutions. When the coolant flows through the bent heat exchange channel formed by the folded fins 4, the fluid boundary layer redevelops at each bend, resulting in a sudden increase in the local Reynolds number and a convective heat transfer coefficient that is more than 30% higher than that of the traditional straight-fin water channel structure. The thin-walled corrugated structure of the folded fins 4 has compressible elastic deformation capability along the thickness direction of the cold plate 3. When the cold plate 3 and the water channel plate 5 experience thermal expansion differences under cyclic operating conditions, the thin wall of the folded fins 4 absorbs this thermal expansion difference through elastic deformation, ensuring that the stress at the welding interface between the cold plate 3 and the water channel plate 5 remains within the allowable range. Under long-term operating conditions, welding interface failure will not occur due to thermal expansion differences. The folded fins 4 thus simultaneously perform two functions: firstly, as a convection heat transfer enhancement structure to improve heat dissipation efficiency; and secondly, as a thermal expansion difference absorption structure to ensure the long-term reliability of the fully welded sealed structure. These two functions arise from the same structure, eliminating the design prerequisites of additional components such as flexible thermal interface materials, sealing rings, and mechanical seals in traditional solutions. This significantly reduces the number of parts, assembly steps, and weak points prone to long-term failure in the overall structure.

[0037] The specific process and interface position relationship of the vacuum reflow soldering connection are detailed below. A continuous metal bonding layer is formed between the lower surface of the ceramic substrate of each of the six TPAK power units 1 and the upper surface of the cold plate 3 using lead-free solder paste. This continuous metal bonding layer completely replaces the flexible thermal interface materials such as thermal grease or thermal pads used in traditional solutions. There is no flexible interface material between the lower surface of the ceramic substrate and the upper surface of the cold plate 3, thus eliminating long-term failure modes such as aging, migration, and drying of the thermal grease. The thickness of the metal bonding layer is preferably 50 to 100 micrometers, and the thermal conductivity of the bonding layer is approximately 160 watts per meter Kelvin, which is more than 30 times the thermal conductivity of traditional thermal grease, reducing the interface thermal resistance between the lower surface of the ceramic substrate and the upper surface of the cold plate 3 by more than 80% compared to the thermal grease solution.

[0038] Specifically, the brazing interfaces between the upper and lower surfaces of the folded fins 4 and the inner surfaces of the cold plate 3 and the water channel plate 5, respectively, the brazing interface between the inner surface of the cold plate 3 and the corresponding mounting surface on the water channel plate 5, and the reflow soldering interface between the lower surface of the ceramic substrate of the TPAK power unit 1 and the upper surface of the cold plate 3, are performed in the following sequence: vacuum brazing followed by vacuum reflow soldering. The process is implemented by assembling the upper side of the folded fins 4 with the cold plate 3 and the lower side of the folded fins 4 with the water channel plate 5 into an assembly, placing the entire assembly in a vacuum brazing furnace, and evacuating to 10°C. -3 The temperature is measured in Pascals. The temperature is slowly increased to approximately 580 degrees Celsius according to a preset temperature profile, allowing the Al-Si solder to fully melt and wet all brazing interfaces. This temperature is then maintained for 5 to 15 minutes, allowing the liquid solder to flow, spread, and fill evenly at each brazing interface. Afterward, the temperature is slowly reduced to room temperature according to the preset temperature profile, allowing the solder to solidify and form a continuous metallic bonding layer. The entire process ensures that the two brazing interfaces are simultaneously welded within a shared solder temperature window. Then, lead-free solder paste is applied between the ceramic substrate and the cold plate of each of the six TPAK power units 1, and the assembly is placed in a vacuum furnace for vacuum reflow soldering. Due to the vacuum environment, the solder layer is free of oxide inclusions and porosity defects, with a porosity of less than 0.5% at the weld interface. This results in high interface strength and good density, meeting the requirements for long-term reliability and vibration and shock resistance of automotive-grade AEC-Q100 and ISO 26262 standards.

[0039] The specific connection and positional relationships of the independent temperature measuring plate 8, temperature sensing element 10, thermally conductive adhesive 11, and self-tapping screw 13 are detailed below. The independent temperature measuring plate 8 is a long strip-shaped printed circuit board extending along the single-row arrangement direction of the six TPAK power units 1. The independent temperature measuring plate 8 is positioned above the top plastic-encapsulated shell 9 of the six TPAK power units 1, with its lower surface parallel to and opposite to the upper surface of the top plastic-encapsulated shell 9 of the six TPAK power units 1. Six temperature measuring points are integrated on the independent temperature measuring plate 8, corresponding one-to-one along the single-row arrangement direction of the six TPAK power units 1. A temperature sensing element 10 is installed at each measuring point, such that the positions of the six temperature sensing elements 10 correspond to the geometric center directly above the six TPAK power units 1. Each temperature sensing element 10 independently collects the surface temperature of the plastic-encapsulated shell of the corresponding TPAK power unit 1. The temperature sensing element 10 can be a thermocouple element or an NTC thermistor element. See also... Figure 7 The independent temperature measuring plate 8 is positioned by positioning pins 13 and locked in place by self-tapping screws 14. Specifically, the plastic body of the positive and negative welding copper busbar assembly 7 is provided with two positioning pins, namely the independent temperature measuring plate positioning pin and the independent temperature measuring plate positioning pin. The independent temperature measuring plate 8 has positioning holes at corresponding positions. During assembly, the positioning holes of the independent temperature measuring plate 8 are fitted into the two positioning pins, and the two positioning pins together define the precise position of the independent temperature measuring plate 8 relative to the positive and negative welding copper busbar assembly 7. Then, the independent temperature measuring plate 8 is locked and fixed to the plastic body of the positive and negative welding copper busbar assembly 7 by two ST2.9*6.5 self-tapping screws 13. The self-tapping screws 13 pass through the independent temperature measuring plate 8 and engage with the threaded holes on the plastic body of the positive and negative welding copper busbar assembly 7, applying a locking force perpendicular to the plate surface to the independent temperature measuring plate 8. The plastic body of the positive and negative soldering copper busbar assembly 7 is also equipped with an insulating barrier and TPAK pin guide holes, which are used to achieve electrical insulation and position guidance between the power terminals of the TPAK power unit 1 and the positive and negative soldering copper busbar assembly 7, respectively. See Figure 8The contact structure between the sensing surface of the temperature sensing element 10 and the surface of the top plastic encapsulation shell 9 of the TPAK power unit 1 is described in detail below. An elastic structure for pressing the temperature sensing element 10 is provided on the plastic body of the positive and negative soldering copper busbar assembly 7. This elastic structure applies an elastic preload force to the temperature sensing element 10 in a direction perpendicular to the surface of the top plastic encapsulation shell 9 of the TPAK power unit 1, ensuring that the sensing surface of the temperature sensing element 10 and the surface of the top plastic encapsulation shell 9 of the TPAK power unit 1 remain in elastic contact. Thermally conductive adhesive 11 is coated between the sensing surface of the temperature sensing element 10 and the surface of the top plastic encapsulation shell 9 of the TPAK power unit 1. This thermally conductive adhesive 11 fills the microscopic gaps at the contact interface, further reducing the interface thermal resistance and improving temperature measurement accuracy. The presence of the elastic preload force prevents the sensing surface of the temperature sensing element 10 from detaching from or shifting position from the surface of the top plastic encapsulation shell 9 of the TPAK power unit 1 under vehicle vibration conditions; simultaneously, the presence of the thermally conductive adhesive 11 makes the thermal resistance at the contact interface controllable and stable. The independent temperature measuring board 8 is also equipped with a communication pin for communicating with the external drive control PCBA 15. The temperature signals collected by the six temperature sensing elements 10 are transmitted to the external drive control PCBA 15 via the communication pin, enabling real-time independent monitoring of the housing temperature of the six TPAK power units 1. Since each TPAK power unit 1 independently constitutes a bridge arm, the six independently collected temperature data can directly reflect the independent housing temperature distribution of each phase's upper and lower pipes in the three-phase full-bridge system. This allows for precise location of fault modes such as current sharing differences between phases, localized overheating, and temperature imbalances, providing phase-specific and pipe-specific temperature field information for the vehicle's thermal management system. The precision of this temperature field information is far superior to the single-point temperature information provided by the traditional DBC substrate's built-in NTC solution, enabling the vehicle's thermal management system to perform temperature optimization control based on higher-dimensional temperature field data.

[0040] The specific connection relationships of the bus capacitor 12, the three-phase welded copper busbar 6, and the positive and negative welded copper busbar assembly 7 are detailed below. The bus capacitor 12 is a film capacitor structure located on one side of the six TPAK power units 1. The positive and negative welded copper busbar assembly 7 includes a positive copper busbar and a negative copper busbar, located on one side of the power terminals of the six TPAK power units 1, and is electrically insulated and fixed in position by a plastic body. The three-phase welded copper busbar 6 is located on the other side of the six TPAK power units 1, and is divided into three independent copper busbars: U-phase, V-phase, and W-phase. Each phase copper busbar is simultaneously connected to the midpoint terminal of the upper and lower tubes of the corresponding phase TPAK power unit 1. (See also...) Figures 5-6In this circuit, there are six laser-welded joints 102 between the three-phase welded copper busbar 6 and the six TPAK power units 1, corresponding to the midpoint terminals of the six TPAK power units 1. Similarly, there are six laser-welded joints between the positive and negative welded copper busbar assembly 7 and the bus capacitor 12 and the six TPAK power units 1, corresponding to the connection positions between the positive and negative terminals of the six TPAK power units 1 and the bus capacitor 12. Laser welding forms a copper-to-copper metallic bond, reducing contact resistance by more than 80% and parasitic inductance by more than 40% compared to traditional bolted connections. It also completely eliminates bolt loosening failure modes, significantly improving the overall electrical performance and long-term reliability of the power circuit.

[0041] The drive control PCBA15 is positioned above the power brick structure comprised of the independent temperature measuring board 8, the positive and negative welding copper busbar assembly 7, the three-phase welding copper busbar 6, and the six TPAK power units 1. It is mechanically fixed using six sets of hexagonal studs and two sets of hexagonal studs, and securely connected to the power brick structure using ten sets of M5*16 screws 14. The drive control PCBA15 integrates six independent drive circuits, sampling circuits, and isolation circuits, corresponding to the gate drives of the six TPAK power units 1. The drive control PCBA15 also receives six temperature signals transmitted from the independent temperature measuring board 8 via communication pins, enabling real-time temperature signal acquisition and fault diagnosis. The gate signals of the six TPAK power units 1 are led out from the top of the TPAK power unit 1 through power terminals, pass through the plastic body of the positive and negative welding copper busbar assembly 7 via TPAK pin guide holes, and are then connected to the drive control PCBA15 via welding. As can be seen from the above connection relationships, the closed-channel single-parallel integrated power semiconductor module of this embodiment highly integrates the TPAK power unit 1, the closed-channel cold plate structure, the three-phase welded copper busbar 6, the positive and negative welded copper busbar assembly 7, the bus capacitor 12, the independent temperature measuring board 8, and the drive control PCBA 15 into one integrated power brick structure. The power brick integrates a three-phase full-bridge power circuit, a drive sampling circuit, and a heat dissipation system. Externally, only a high-voltage bus interface, a low-voltage drive interface, and a coolant interface need to be reserved. It can be directly assembled as a standard module into the high-voltage power conversion equipment such as new energy vehicle motor controllers, range extenders, and water pump controllers, greatly simplifying the overall structural design and assembly process of the equipment.

[0042] The overall assembly process of Example 1 is described as follows: First, the folded fins 4 are placed inside the cavity of the channel plate 5, the cold plate 3 is assembled and sealed from above the channel plate 5, welding plates are placed at the welding interface, and the assembly is positioned and clamped using a fixture. Second, the entire assembly is placed in a vacuum brazing furnace, and welding is completed at three locations on the two welding surfaces of the channel under a vacuum environment according to a preset temperature curve, forming a complete welded channel structure. Third, lead-free solder paste is applied to the six TPAK welding bosses on the channel plate 3, and the six TPAK power units 1 are aligned and positioned on the assembly fixture in a symmetrical order of three upper tubes and three lower tubes. Fourth, the assembly from step three is placed in a vacuum reflow oven, and vacuum reflow soldering is completed under a vacuum environment according to a preset temperature curve. Fifth, the plastic body of the positive and negative welding copper busbar assembly 7 is installed on top of the welded power brick core structure, and the positive and negative copper busbars are aligned with the positive and negative terminals of the six TPAK power units 1 through the TPAK pin guide holes. Step 6: Laser welding is used to complete six laser welding points between the three-phase welding copper busbar 6 and the midpoint terminal of the TPAK power unit 1, and twelve laser welding points between the positive and negative welding copper busbar assembly 7 and the positive and negative terminals and bus capacitor 12 of the TPAK power unit 1, forming a complete electrical interconnection. Step 7: The independent temperature measuring plate 8 is positioned using two positioning pins 13, and six temperature sensing elements 10 are placed within the elastic structure on the plastic body of the positive and negative welding copper busbar assembly 7. The sensing surfaces of the temperature sensing elements 10 are pre-coated with thermally conductive adhesive 11. The independent temperature measuring plate 8 is locked and fixed using two ST2.9*6.5 self-tapping screws 13, so that the sensing surfaces of the temperature sensing elements 10 establish elastic contact with the surface of the top plastic-encapsulated shell 9 of the six TPAK power units 1. Step 8: The drive control PCBA 15 is mechanically fixed to the core structure of the power brick using hexagonal studs, hexagonal studs 14, and M5*16 screws 16, completing the connection between the drive signal and the temperature signal. The entire assembly process involves no thermal grease application or sealing ring assembly, making it simple, highly consistent, and easy to automate.

[0043] Example 2. This example provides a variant of Example 1, applicable to low-power range extender controllers or water pump controllers. The difference between this example and Example 1 is that the number of TPAK power units 1 can be adjusted according to the specific application scenario. In some low-voltage, low-power applications, such as water pump controllers or low-voltage auxiliary drive controllers, the number of TPAK power units 1 can be reduced to four or two, corresponding to single-phase or two-phase full-bridge topologies. In some high-voltage, high-power applications, such as range extender controllers or high-power drive controllers, the number of TPAK power units 1 can be increased to twelve, corresponding to a three-phase full-bridge topology with two TPAK power units connected in parallel per phase. In this case, the single-row symmetrical arrangement principle is still maintained, ensuring that every two parallel TPAK power units 1 are symmetrical about the geometric center line of the bridge arm, and the current path length from both to the bus capacitor 12 remains equal, thereby maintaining current sharing performance. In this embodiment, the dimensions of the cold plate 3, folded fins 4, and water channel plate 5 are scaled proportionally according to the number of TPAK power units 1, but their connection relationships, reflow soldering process, brazing process, and closed water channel structure are the same as in Embodiment 1. The length of the independent temperature measuring plate 8 and the number of temperature sensing elements 10 are also adjusted accordingly to match the number of TPAK power units 1, achieving one-to-one phase and pipe-specific temperature acquisition. The remaining structure of this embodiment is the same as in Embodiment 1. Thus, this embodiment can also achieve the core technical effects of precise mapping of a single pipe to a single bridge arm, the dual function of folded fins absorbing thermal expansion differences and enhancing convective heat transfer, the integral molding of the two welding surfaces of the water channel through vacuum brazing in one step, and phase and pipe-specific temperature acquisition by the independent temperature measuring plate at the top. By adjusting the number of TPAK power units 1 in this embodiment, the closed water channel single-parallel integrated power semiconductor module of the present invention can be adapted to new energy vehicle power electronic equipment of various power levels, covering the complete application spectrum from low-voltage auxiliary drive to high-voltage main drive. The modular design facilitates standardized production and cross-platform reuse.

[0044] Example 3. This example provides another variant of Example 1, mainly varying the types of temperature sensing elements and the configuration of the temperature measurement architecture. In this example, the temperature sensing element 10 can be a thermocouple element, such as a K-type thermocouple or a T-type thermocouple, with the hot junction (number 105) of the thermocouple welded to the independent temperature measuring plate 8. Alternatively, the temperature sensing element 10 can be an NTC thermistor element, mounted on the corresponding temperature measuring point on the independent temperature measuring plate 8 using a surface mount process. In some applications requiring higher temperature measurement accuracy, each temperature measuring point on the independent temperature measuring plate 8 can integrate two types of temperature sensing elements 10: a thermocouple element and an NTC thermistor element arranged in parallel, respectively collecting temperature data from the surface of the same TPAK power unit 1 housing. This dual redundancy verification of temperature data is achieved through two independent physical temperature measurement principles, further improving the reliability of temperature monitoring. In certain applications requiring measurement of junction temperature transient response, the independent temperature measuring plate 8 can also integrate an infrared temperature measuring module to measure the infrared radiation of the top plastic-encapsulated shell 9 of the TPAK power unit 1 in a non-contact manner, obtaining faster temperature transient response data. This forms a dual-level temperature monitoring system with the elastic pressure-sensitive temperature sensing element 10, providing both steady-state and transient temperature monitoring. In this embodiment, the elastic structure pressing the temperature sensing element 10 onto the plastic body of the positive and negative welded copper busbar assembly 7 can adopt various elastic forms such as a cantilever beam spring structure, a compression helical spring structure, or a rubber elastomer structure. The elastic deformation of the elastic structure is preferably between 0.2 mm and 1.0 mm, and the elastic preload is preferably between 0.5 N and 5 N, ensuring that the contact pressure between the sensing surface of the temperature sensing element 10 and the surface of the top plastic-encapsulated shell 9 of the TPAK power unit 1 remains within a reasonable range, guaranteeing good heat transfer contact without damaging the plastic-encapsulated shell of the TPAK power unit 1 due to excessive pressure. The thermally conductive adhesive 11 is preferably made of epoxy-based or silicone-based thermally conductive adhesive, with a thermal conductivity of not less than 2 watts per meter Kelvin and an operating temperature range covering -40 degrees Celsius to 150 degrees Celsius. The remaining structure of this embodiment is the same as that of Embodiment 1. Through the diverse configurations of temperature sensing element types and elastic structures in this embodiment, the closed-channel single-parallel integrated power semiconductor module of the present invention can be adapted to new energy vehicle application scenarios with different accuracy requirements, different response speed requirements, and different environmental conditions.

[0045] Example 4. This example provides a variant of the dual-sided cooling solution based on Example 1, suitable for extreme operating conditions with higher power density requirements. The difference between this example and Example 1 is that, in addition to the cold plate 3 arranged below the TPAK power unit 1, an upper cold plate is also arranged above the TPAK power unit 1, forming a dual-sided cooling structure. Specifically, the upper cold plate is located between the independent temperature measuring plate 8 and the top plastic-encapsulated shell 9 of the TPAK power unit 1. The lower surface of the upper cold plate is tightly bonded to the surface of the top plastic-encapsulated shell 9 of the TPAK power unit 1 through a thermally conductive adhesive layer. Folded fins are also arranged inside the upper cold plate, and vacuum brazed with the upper water channel plate to form an upper closed water channel. The upper cold plate and the lower cold plate (i.e., the cold plate 3) are connected in series or parallel through coolant pipelines to form a complete dual-sided cooling circulation loop. In this embodiment, the independent temperature measuring plate 8 and the temperature sensing element 10 can be integrated into the gap between the lower surface of the upper cooling plate and the top plastic-encapsulated shell 9 of the TPAK power unit 1, or integrated near the coolant flow channel inside the upper cooling plate, for simultaneously collecting the shell temperature and coolant temperature of the TPAK power unit 1. The rest of the structure in this embodiment is the same as in Embodiment 1. Through the double-sided cooling structure of this embodiment, the total heat dissipation capacity of the TPAK power unit 1 can be further improved, the rated output current density of the module can be increased by more than 30% compared with Embodiment 1, and the power density can exceed 150 kW / L, which is suitable for extreme working conditions such as high-performance pure electric vehicle main drive motor controllers, high power density commercial vehicle drive controllers, and racing-grade motor controllers. However, it should be noted that the double-sided cooling structure of this embodiment will increase the overall module size and cost, and increase the complexity of the manufacturing process. In practical applications, the single-sided cooling structure of Embodiment 1 or the double-sided cooling structure of this embodiment should be selected according to the specific power level and cost constraints.

[0046] The specific process parameters and temperature profiles for the three-stage vacuum brazing of the two weld surfaces of the waterway are further detailed below. The vacuum brazing equipment preferably uses a vacuum brazing furnace with programmed temperature control. The working vacuum level is preferably less than or equal to 10^-3 Pa, and the temperature uniformity within the brazing furnace is preferably within ±4 degrees Celsius. The brazing filler metal is preferably an Al-Si eutectic filler metal, such as Al-12Si filler metal (an aluminum-silicon alloy containing 12% silicon) or Al-Si-Mg filler metal (an aluminum-silicon alloy with a small amount of magnesium). The former has a melting point of 577 degrees Celsius, while the latter has a slightly lower melting point and better oxidation resistance. The filler metal can be a pre-coated layer, a foil, or a paste, with the appropriate filler metal placement method selected according to the geometry of each brazing interface. The complete brazing temperature profile includes four stages. The first stage is the preheating stage: the assembly is slowly heated from room temperature to 300 degrees Celsius, preferably at a rate of 3 to 8 degrees Celsius per minute. This preheating stage homogenizes the internal temperature of the assembly and allows the organic solvents in the pre-coated solder to fully evaporate. The second stage is the heating stage: the temperature is further increased from 300 degrees Celsius to a brazing temperature of 590 to 600 degrees Celsius, preferably at a rate of 5 to 10 degrees Celsius per minute, allowing the solder to fully melt above its eutectic melting point. The third stage is the holding stage: the temperature is held at 590 to 600 degrees Celsius for 5 to 15 minutes, allowing the liquid solder to fully wet, spread, and fill the three brazing interfaces: the upper side of the folded fin 4 and the inner surface of the cold plate 3; the lower side of the folded fin 4 and the inner surface of the channel plate 5; and the assembly surface of the cold plate 3 and the channel plate 5, forming a dense, non-porous, continuous metallic bonding layer. The fourth stage is the cooling stage: the brazing temperature is slowly reduced to room temperature, preferably at a rate of 2 to 5 degrees Celsius per minute. This ensures more uniform stress release during the solidification of the brazing filler metal and avoids cracking or fissures at the weld interface caused by rapid cooling. The entire brazing process takes approximately 3 to 5 hours. Under the above process conditions, the porosity of the three brazing interfaces can be controlled below 0.5%, and the shear strength of the weld interface is preferably not less than 80 MPa, which fully meets the requirements of automotive-grade AEC-Q100 and ISO 26262 standards for long-term reliability, vibration and shock resistance, and temperature cycling performance. Due to the vacuum environment, no oxides are formed in the brazing filler metal layer during the brazing process; at the same time, the alumina surface film of the aluminum alloy is reduced under vacuum, high temperature, and magnesium activation, allowing the liquid brazing filler metal to directly wet the surface of the aluminum alloy base material. This is the physical basis for the folded fins 4, cold plate 3, and water channel plate 5 all being made of aluminum alloy and able to form a dense metal bonding layer through vacuum brazing.

[0047] To further illustrate the irreplaceability of the core technical features of this invention, three comparative examples are given below. Comparative Example 1: A comparative scheme in which the folded fins 4 are removed and the space between the cold plate 3 and the water channel plate 5 is replaced with a traditional straight fin structure. The remaining structure in the comparative scheme is the same as in Example 1, except that the folded fins 4 are replaced with multiple independent straight fins, with the two ends of the straight fins welded to the inner surface of the cold plate 3 and the inner surface of the water channel plate 5, respectively. Analysis reveals the following shortcomings of the comparative scheme: First, the heat exchange area of ​​the straight-fin structure is approximately 60% to 70% of that of the folded fin 4 of the same volume, resulting in a convective heat transfer efficiency that is more than 20% lower than that of Example 1. Second, the straight-fin structure is a rigid support structure along the thickness direction of the cold plate 3, lacking elastic deformation capability. When the cold plate 3 and the water channel plate 5 experience thermal expansion differences under cyclic operating conditions, the thermal stress at the welding interface between the straight fin and the cold plate 3 / water channel plate 5 cannot be absorbed. Under long-term operating conditions, fatigue cracks or even ruptures are prone to occur at the welding interface, leading to coolant leakage. Third, multiple independent straight fins need to be welded separately, resulting in cumbersome welding procedures and poor process consistency. Therefore, the dual functions of enhancing convective heat transfer and absorbing thermal expansion differences undertaken by the folded fin 4 in this invention cannot be replaced by a simple straight-fin structure. The physical mechanism lies in the fact that the thin-walled corrugated geometry of the folded fin 4 simultaneously allows the fluid boundary layer to redevelop at each bend (enhancing convective heat transfer) and provides elastic deformation capability along the thickness direction of the cold plate 3 (absorbing thermal expansion differences). These two functions emerge from the same structure and are the core physical basis for achieving long-term reliability of the all-welded metal sealing structure in this invention.

[0048] Comparative Example 2: The independent top temperature measuring plate 8 was removed, and the temperature monitoring was replaced with a comparative scheme using a traditional DBC substrate with an integrated NTC. The rest of the structure in the comparative scheme is the same as in Example 1, except that the independent temperature measuring plate 8, temperature sensing element 10, and thermally conductive adhesive 11 were removed. The temperature sensing was replaced by integrating an NTC thermistor bonding chip on the ceramic substrate inside each TPAK power unit 1, and the temperature signal was led out through bonding wires. Analysis reveals the following shortcomings of the comparative scheme: First, since a continuous metal bonding layer is formed between the lower surface of the ceramic substrate and the upper surface of the cold plate 3 through vacuum reflow soldering, the ceramic substrate becomes part of the soldering interface. Integrating the NTC thermistor bonding chip on the ceramic substrate significantly reduces the flatness and soldering strength of the soldering interface, and the NTC thermistor chip itself may fail due to the high temperature of the soldering process. Second, the traditional DBC built-in NTC scheme can only obtain the approximate temperature of each TPAK power unit 1 at a single point, and the temperature data reflects the temperature of the ceramic substrate rather than the temperature of the plastic encapsulation shell surface, resulting in a large steady-state temperature difference with the actual chip junction temperature, affecting the accuracy of temperature monitoring. Third, this comparative scheme cannot achieve phase-by-phase and pipe-by-pipe positioning of fault modes such as current sharing differences between phases and local overheating, and the dimensionality of temperature information is significantly reduced compared to Example 1. Therefore, the structure of the top independent temperature measuring plate 8 of the present invention with elastic pressing and thermal conductive adhesive is not a simple replacement of the traditional DBC built-in NTC solution. Rather, it is an inevitable choice of temperature measuring structure forced by the premise that the flexible interface material of the ceramic substrate is eliminated by the vacuum reflow soldering. After the ceramic substrate becomes the welding interface, the DBC built-in NTC solution is no longer feasible, and temperature monitoring must be reconstructed into an elastic pressing temperature measuring solution on the outside of the plastic-encapsulated shell.

[0049] To further explain the physical mechanisms underlying the unexpected technical effects of the core features of this invention, the relevant mechanisms are detailed below from three perspectives: mechanics, thermodynamics, and fluid mechanics. First, the enhanced convective heat transfer mechanism of the folded fins 4. When fluid flows through a conventional straight-fin channel, the fluid boundary layer continuously grows on the surface of the straight fin, becoming thicker with increasing distance from the inlet, and the convective heat transfer coefficient monotonically decreases along the flow direction. However, when fluid flows through the bent heat transfer channel of the folded fins 4, the fluid is forced to change its flow direction at each bend, the preceding boundary layer is peeled off at the bend, and a new boundary layer regrows from the bend outlet. This periodic boundary layer regrowth process makes the average boundary layer thickness within the entire folded fin 4 much lower than that of the straight-fin channel, increasing the overall convective heat transfer coefficient by more than 30%. Furthermore, fluid separation and reattachment at the bends cause a momentary increase in the local Reynolds number, entering the turbulent transition zone, where turbulent pulsations further enhance heat transfer. This phenomenon, known in fluid dynamics as the periodic boundary layer redevelopment effect, is the physical essence of the superior heat dissipation performance of the folded fin 4 compared to the straight-finned channel. Secondly, the thermal expansion difference absorption mechanism of the folded fin 4. Under cyclical temperature changes, when the temperature of the cold plate 3 and the channel plate 5 changes from -40 degrees Celsius to 150 degrees Celsius, the coefficient of thermal expansion of the aluminum alloy is approximately 23 x 10⁻⁶ Kelvin. A temperature change of 190 Kelvin causes a dimensional change of approximately 0.4 mm per 100 mm of channel width along both surfaces. Traditional straight-fin structures, with rigid support along the thickness of the cold plate, cannot absorb the aforementioned thermal expansion difference; the welded interface will bear all the thermal expansion stress, making it prone to fatigue cracks under long-term conditions. In contrast, the thin-walled corrugated structure of the folded fin 4 has compressible elasticity along the thickness of the cold plate. The thin wall of the folded fin 4 can buckle locally, and the corrugation angle can be finely adjusted, allowing the relative displacement between the cold plate 3 and the channel plate 5 to be absorbed by the elastic deformation of the folded fin 4. This phenomenon, known as thin-wall buckling elasticity in structural mechanics, is the physical essence of the long-term reliability of the fully welded sealed structure without flexible interface materials achieved by the folded fins 4. Third, the physical feasibility mechanism of the shared brazing temperature window across the two weld surfaces of the water channel. The folded fins 4, cold plate 3, and water channel plate 5 are all made of aluminum alloy, and their brazing temperature windows are completely consistent. Therefore, all three brazing interfaces can be welded within the same temperature (590°C to 600°C) and the same holding time (5 to 15 minutes), without the need for multiple heating and holding cycles. This temperature window compatibility is the physical basis for the one-time vacuum brazing of the three weld surfaces into a single integral shape. Fourth, the response speed advantage mechanism of the elastic pressure temperature measurement of the top independent temperature measuring plate 8. In the traditional DBC substrate with built-in NTC solution, the NTC thermal bonding chip is located on the ceramic substrate, near the chip, about 200 to 500 micrometers away from the chip surface. The temperature signal needs to be conducted through multiple layers such as ceramic layer and copper layer. There are multiple thermal resistance layers and thermal capacitance layers in the conduction path, which results in a long transient response time constant of the temperature signal (about 500 milliseconds to 2 seconds).The temperature sensing element 10 of the independent temperature measuring plate 8 in this invention has only a thin layer of thermally conductive adhesive (approximately 50 to 100 micrometers thick) between its sensing surface and the surface of the plastic-encapsulated shell 9 on the top of the TPAK power unit 1. This thermally conductive adhesive has low thermal resistance and low heat capacity, significantly shortening the transient response time constant of the temperature signal (approximately 50 to 300 milliseconds). This makes the real-time temperature monitoring performance of this invention superior to traditional DBC-embedded NTC solutions. The physical mechanisms at these four levels collectively support the unexpected technical effects of the core technical features of this invention, enabling it to achieve a paradigm-level innovation in the field of power semiconductor modules for new energy vehicles, integrating structure and process.

[0050] The above embodiments and comparative examples together illustrate that in the closed-channel single-parallel integrated power semiconductor module of the present invention, the six TPAK power units 1 are arranged symmetrically in a single row, the folded fins 4 form a closed channel structure, the two welding surfaces of the channel are vacuum-brazed in one step, and the top independent temperature measuring plate 8 is reinforced with elastic pressure and thermally conductive adhesive. These four core technical features have an inseparable causal progression relationship, constituting a paradigm-level innovation in power semiconductor module structure. Specifically, the precise mapping of the six TPAK power units 1 to a single bridge arm reduces the effective size of each ceramic substrate to 1 / 6 of a traditional 6-in-1 module. This reduction in ceramic substrate size makes the thermal stress distribution between it and the cold plate 3 more uniform, and significantly reduces the area of ​​thermal stress concentration, providing a geometric prerequisite for eliminating flexible thermal interface materials and directly using vacuum brazing to form a continuous metal bonding layer. After eliminating the flexible thermal interface material, the difference in thermal expansion between the cold plate 3 and the channel plate 5 under the operating temperature cycle must be borne by the structure itself. The elastic deformation capacity of the thin-walled corrugated geometry of the folded fins 4 along the thickness direction of the cold plate 3 perfectly undertakes this function. At the same time, the bending geometry of the folded fins 4 allows the fluid boundary layer to redevelop at each bend, thereby improving the convective heat transfer coefficient. This results in a dual function of enhanced heat transfer and absorption of thermal expansion. The folded fins 4 and the cold plate 3, the folded fins 4 and the channel plate 5, and the cold plate 3 and the channel plate 5 are all connected by vacuum brazing to form continuous welds. This completely eliminates the mechanical seal of the sealing ring in the closed channel structure. The two brazing interfaces share the same Al-Si brazing filler metal temperature window, thus allowing the welding to be completed in the same vacuum brazing process, achieving integral one-time forming. Since the ceramic substrate has become an integral part of the welding interface, the traditional DBC-embedded NTC solution is no longer feasible. Temperature monitoring has been forced to be restructured into an independent temperature measuring plate on the outside of the top plastic-encapsulated shell, plus an elastic pressing and thermally conductive adhesive structure (premise four). This passive restructuring has actually brought about an active capability upgrade: the shell temperature of each TPAK power unit 1 is independently acquired, upgrading the temperature information from a single-point approximate temperature to a six-point temperature field distribution with phase and pipe separation, thus improving the information dimension of temperature monitoring. The above four premises constitute an irreversible causal chain: a single pipe corresponding to a single bridge arm (premise one) forces vacuum reflow soldering to replace silicone grease; vacuum reflow soldering replacing silicone grease (premise two) forces folded fins to absorb thermal expansion; folded fins absorbing thermal expansion (premise three) forces the one-time brazing of the two welding surfaces of the water channel into a single integral shape; and the one-time brazing of the two welding surfaces of the water channel at three locations (premise four) forces the independent temperature measuring plate on the top to replace the DBC-embedded NTC. The replacement of any one feature in isolation will break the entire chain. Therefore, the combination relationship between the features of this invention is an irreplaceable paradigm-level overall innovation, rather than a simple combination of conventional structures.

[0051] The closed-channel single-parallel integrated power semiconductor module of this invention can be widely used in the field of power electronic control equipment for new energy vehicles, including but not limited to main drive motor controllers for pure electric vehicles, range extender controllers for range-extended hybrid electric vehicles, drive controllers for plug-in hybrid electric vehicles, power control units for fuel cell vehicles, water pump controllers for electric vehicles, thermal management controllers, and air conditioning compressor controllers. This invention is also applicable to high-power-density power conversion devices in other fields, such as traction converters for rail transit, distributed photovoltaic grid-connected inverters, high-power frequency converters for industrial applications, and energy storage PCS converters. Those skilled in the art should understand that the above embodiments are merely preferred embodiments of this invention and are not intended to limit the scope of protection of this invention. Without departing from the concept of this invention, those skilled in the art can make conventional structural substitutions, adjustments to connection relationships, and changes in material selection under the guidance of this invention, and all such modifications and variations should fall within the scope of protection defined by the claims of this invention.

Claims

1. A closed-channel single-parallel integrated power semiconductor module, characterized in that: The system includes six TPAK power units (1) arranged symmetrically in a single row along the length of the cold plate (3). Three upper-tube TPAK power units and three lower-tube TPAK power units in the six TPAK power units (1) are arranged alternately and symmetrically to form a three-phase full bridge. Folded fins (4) are provided between the cold plate (3) and the water channel plate (5). The two sides of the folded fins (4) are vacuum brazed to the inner surface of the cold plate (3) and the inner surface of the water channel plate (5) to form a closed water channel. The lower surface of the ceramic substrate of the TPAK power unit (1) is vacuum reflow soldered to the upper surface of the cold plate (3) to form a continuous metal bonding layer. An independent temperature measuring plate (8) is provided above the plastic-encapsulated shell (9) on the top of the TPAK power unit (1). A temperature sensing element (10) is provided on the independent temperature measuring plate (8). The sensing surface of the temperature sensing element (10) is in elastic contact with the surface of the plastic-encapsulated shell (9) on the top of the TPAK power unit (1) through thermally conductive adhesive (11).

2. The closed-channel single-parallel integrated power semiconductor module according to claim 1, characterized in that: Each of the six TPAK power units (1) contains a single SiC MOSFET chip or a single IGBT chip. Each TPAK power unit (1) independently constitutes a bridge arm in a three-phase full-bridge topology, so that the current path length from the power terminal of each TPAK power unit (1) to the bus capacitor (12) is equal to that of each other.

3. The closed-channel single-parallel integrated power semiconductor module according to claim 2, characterized in that: There is no flexible thermal interface material between the lower surface of the ceramic substrate of the TPAK power unit (1) and the upper surface of the cold plate (3); the continuous metal bonding layer formed by vacuum reflow soldering directly connects the ceramic substrate and the cold plate (3).

4. The closed-channel single-parallel integrated power semiconductor module according to claim 3, characterized in that: The folded fins (4) are thin-walled corrugated structures. The thin-walled corrugated structures have elastic deformation capabilities along the thickness direction of the cold plate (3) to bear the thermal expansion difference between the cold plate (3) and the water channel plate (5). The folded fins (4) are continuously arranged along the flow direction of the coolant to form multiple bent heat exchange channels.

5. The closed-channel single-parallel integrated power semiconductor module according to claim 4, characterized in that: The brazing interface between the folded fins (4) and the inner surface of the cold plate (3), and the brazing interface between the folded fins (4) and the inner surface of the water channel plate (5) are achieved by vacuum brazing, with the furnace temperature typically around 580°C; then, the vacuum reflow soldering interface between the lower surface of the ceramic substrate and the upper surface of the cold plate (3) is achieved by vacuum reflow soldering, using lead-free solder paste, with a furnace peak temperature of 235~245°C.

6. The closed-channel single-parallel integrated power semiconductor module according to claim 5, characterized in that: The independent temperature measuring plate (8) has six temperature measuring points arranged one by one along the single row arrangement direction of the six TPAK power units (1). Each temperature measuring point independently collects the surface temperature of the plastic-encapsulated shell of the corresponding TPAK power unit (1).

7. The closed-channel single-parallel integrated power semiconductor module according to claim 6, characterized in that: The independent temperature measuring plate (8) is positioned by the positioning pin on the positive and negative welding copper busbar assembly (7) and locked and fixed to the plastic body of the positive and negative welding copper busbar assembly (7) by the self-tapping screw (13); the plastic body of the positive and negative welding copper busbar assembly (7) is provided with an elastic structure that presses the temperature sensing element (10), and the elastic structure applies an elastic preload force to the temperature sensing element (10) in a direction perpendicular to the surface of the top plastic encapsulated shell (9) of the TPAK power unit (1).

8. The closed-channel single-parallel integrated power semiconductor module according to claim 1, characterized in that: It also includes a bus capacitor (12), a three-phase welded copper busbar (6), and a positive and negative welded copper busbar assembly (7); the bus capacitor (12), the three-phase welded copper busbar (6), the positive and negative welded copper busbar assembly (7) are connected to the six TPAK power units (1) by laser welding.

9. The closed-channel single-parallel integrated power semiconductor module according to claim 4, characterized in that: The folded fins (4) are made of aluminum alloy, and the vacuum brazing uses Al-Si brazing filler metal.

10. The closed-channel single-parallel integrated power semiconductor module according to claim 4, wherein the surface of the cold plate (3) is provided with an FR4 insulating plate (2).

11. The closed-channel single-parallel integrated power semiconductor module according to claim 6, characterized in that: The temperature sensing element (10) is a thermocouple or an NTC thermistor.

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