Heat dissipation mechanism of silicon carbide power device

Abstract

The utility model relates to the technical field of heat dissipation of silicon carbide devices, in particular to a heat dissipation mechanism of a silicon carbide power device, which comprises a heat dissipation substrate used for installing the silicon carbide power device and a heat dissipation fin group covered above the heat dissipation substrate. The micro-channel is filled with a low-melting-point alloy phase change material; a flow guide cavity is formed between the heat dissipation fin group and the heat dissipation substrate, an air inlet and an air outlet which are communicated with the outside are formed in the flow guide cavity, and a heat conduction column which is thermally coupled with the micro-channel is arranged in the flow guide cavity; through latent heat energy storage of the low-melting-point alloy phase-change material in the micro-channel, efficient heat conduction of the multi-layer substrate and flow field optimization of the flow guide cavity and the heat dissipation fin group, efficient heat export and temperature fluctuation suppression of the silicon carbide power device are achieved, the strict heat dissipation requirement under the high-frequency and high-pressure working condition is met, and the service life of the device is prolonged.

Description

Technical Field

[0001] This utility model relates to the field of heat dissipation technology for silicon carbide devices, and specifically discloses a heat dissipation mechanism for silicon carbide power devices. Background Technology

[0002] Silicon carbide power devices are widely used in new energy vehicles, photovoltaic inverters, and other fields due to their high voltage withstand capability, low loss, and high temperature resistance. However, the concentrated heat generated during operation can easily lead to an increase in junction temperature, affecting device reliability. Traditional heat dissipation mechanisms have the following shortcomings:

[0003] Conventional heat dissipation substrates (such as copper substrates and aluminum substrates) rely on solid-state thermal conductivity, resulting in high thermal resistance. Especially under high-frequency operating conditions, heat is difficult to dissipate quickly, easily forming local hot spots. Traditional fin assemblies dissipate heat through natural convection or forced air cooling, but the airflow distribution is uneven, and the heat dissipation efficiency decreases as the device power increases.

[0004] To address the insufficient heat dissipation efficiency in existing technologies, a heat dissipation mechanism for silicon carbide power devices is proposed to solve the aforementioned problems. Summary of the Invention

[0005] This invention proposes a heat dissipation mechanism for silicon carbide power devices. It improves thermal conductivity by using a high thermal conductivity graphene layer, an intermediate copper alloy layer, and an external aluminum-based support layer. A phase change material in the microchannel buffers heat, and the airflow organization is optimized by the flow channel and heat dissipation fin assembly. Combined with active temperature control by a semiconductor cooling chip, it solves the heat dissipation problem of silicon carbide devices under high loads and meets the requirements for efficient and reliable operation.

[0006] This invention is implemented as follows: a heat dissipation mechanism for a silicon carbide power device includes a heat dissipation substrate for mounting the silicon carbide power device and a heat dissipation fin assembly covering the heat dissipation substrate. The heat dissipation substrate has microchannels arranged in a grid pattern inside, and the microchannels are filled with a low-melting-point alloy phase change material. A flow guiding cavity is provided between the heat dissipation fin assembly and the heat dissipation substrate. The flow guiding cavity has an air inlet and an air outlet communicating with the outside, and a heat-conducting column thermally coupled to the microchannel is provided inside the flow guiding cavity.

[0007] As a preferred heat dissipation mechanism for a silicon carbide power device according to the present invention, the heat dissipation substrate includes a high thermal conductivity graphene layer, an intermediate copper alloy layer, and an outer aluminum base support layer that are in direct contact with the silicon carbide power device. The layers are connected by diffusion welding or vacuum brazing. The heat dissipation fins are fixed to the surface of the aluminum base support layer. The microchannels penetrate the intermediate copper alloy layer, and the low melting point alloy phase change material in the microchannels is in contact with the high thermal conductivity graphene layer.

[0008] As a preferred heat dissipation mechanism for a silicon carbide power device according to this utility model, the heat-conducting column has a hollow structure and a spiral guide plate inside, wherein the spiral direction of the spiral guide plate is consistent with the airflow direction in the guide cavity.

[0009] As a preferred heat dissipation mechanism for a silicon carbide power device according to the present invention, the inner wall of the air guiding cavity is provided with a nano-aerogel heat insulation layer, and a temperature-sensitive shape memory alloy valve is installed at the air inlet. The temperature-sensitive shape memory alloy valve is used to adjust the opening of the air inlet according to the temperature change of the heat dissipation substrate.

[0010] As a preferred heat dissipation mechanism for a silicon carbide power device according to the present invention, the heat dissipation fin group includes at least two layers of parallel fins, and a heat dissipation gap is formed between adjacent two layers of fins. The width of the heat dissipation gap gradually increases from the air inlet to the air outlet.

[0011] As a preferred embodiment of the heat dissipation mechanism for a silicon carbide power device according to this utility model, it further includes a semiconductor cooling chip installed on the outside of the heat dissipation fin assembly. The cold surface of the semiconductor cooling chip is in contact with the heat dissipation fin assembly, and the semiconductor cooling chip is electrically connected to a temperature sensor and a control module. The temperature sensor is attached to the position of the chip on the silicon carbide power device, and the control module is located on the edge of the flow channel cavity. The temperature sensor is used to detect the junction temperature of the silicon carbide power device, and the control module adjusts the operating power of the semiconductor cooling chip according to the temperature sensor data.

[0012] The beneficial effects of this utility model are:

[0013] 1. Phase change materials combined with microchannel structures utilize latent heat storage to smooth temperature fluctuations and prevent device overheating; and the thermal resistance of the heat dissipation substrate is reduced through a high thermal conductivity graphene layer, an intermediate copper alloy layer and an external aluminum-based support layer, enabling rapid heat dissipation.

[0014] 2. The intake air volume is dynamically adjusted by temperature-sensitive shape memory alloy valve plates, and the semiconductor cooling chip is activated on demand, taking into account the heat dissipation requirements under different operating conditions and improving the system energy efficiency ratio; the spiral guide vane enhances airflow disturbance, the gradually spaced fin group optimizes the flow field, and the nano aerogel reduces heat loss, resulting in a compact overall structure and high heat dissipation efficiency. Attached Figure Description

[0015] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.

[0016] Figure 1This is a schematic diagram of the overall structure of this utility model.

[0017] Figure 2 This is a top view of the microchannel structure of this utility model.

[0018] Figure 3 This is a schematic diagram of the air inlet structure of this utility model.

[0019] Figure 4 This is a schematic diagram of the air outlet structure of this utility model.

[0020] The markings in the diagram are: 1. Heat dissipation substrate; 2. Heat dissipation fin assembly; 3. Microchannel; 4. Low melting point alloy phase change material; 5. Airflow guide cavity; 6. Air inlet; 7. Air outlet; 8. Thermal conductive column; 9. High thermal conductivity graphene layer; 10. Intermediate copper alloy layer; 11. External aluminum-based support layer; 12. Spiral airflow guide; 13. Nano-aerogel insulation layer; 14. Temperature-sensitive shape memory alloy valve; 15. Fin; 16. Heat dissipation gap; 17. Semiconductor cooling chip; 18. Temperature sensor; 19. Control module; 20. Silicon carbide power device. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments to aid in understanding its content. Unless otherwise specified, the methods used in this invention are conventional methods; the raw materials and apparatus used, unless otherwise specified, are conventional commercially available products.

[0022] Please see Figure 1-4 A heat dissipation mechanism for a silicon carbide power device includes a heat dissipation substrate 1 for mounting the silicon carbide power device and a heat dissipation fin assembly 2 covering the heat dissipation substrate 1. The heat dissipation substrate 1 has microchannels 3 arranged in a grid pattern inside, and the microchannels 3 are filled with a low-melting-point alloy phase change material 4. A flow guiding cavity 5 is provided between the heat dissipation fin assembly 2 and the heat dissipation substrate 1. The flow guiding cavity 5 is provided with an air inlet 6 and an air outlet 7 communicating with the outside, and a heat-conducting column 8 thermally coupled to the microchannels 3 is provided inside the flow guiding cavity 5.

[0023] In this embodiment: the silicon carbide power device is mounted on the heat dissipation substrate 1. The heat generated by the silicon carbide power device during operation is quickly transferred to the microchannel 3 of the intermediate copper alloy layer 10 through the high thermal conductivity graphene layer 9. The low melting point alloy phase change material 4 in the microchannel 3 absorbs the heat and undergoes a phase change (solid to liquid), using the latent heat of the phase change to store a large amount of heat and suppress the sudden temperature rise of the heat dissipation substrate 1. The heat conduction pillar 8 conducts the heat in the microchannel 3 to the flow guide cavity 5. External air enters from the air inlet 6 and forms turbulence after being disturbed by the spiral flow guide 12, which fully exchanges heat with the heat conduction pillar 8 and the heat dissipation fin group 2. The heat dissipation gap 16 of the heat dissipation fin group 2 is designed with a gradual change to optimize the airflow distribution and accelerate the heat dissipation through the air outlet 7. The temperature-sensitive valve automatically adjusts the air intake according to the temperature of the heat dissipation substrate 1, increasing the heat dissipation capacity at high temperatures. When the junction temperature of the device exceeds the threshold (monitored by the temperature sensor 18), the control module 19 activates the semiconductor cooling chip 17 to actively reduce the temperature of the heat dissipation fin group 2, forming a multi-stage heat dissipation effect.

[0024] As a technical optimization of this utility model, the heat dissipation substrate 1 includes a high thermal conductivity graphene layer 9, an intermediate copper alloy layer 10, and an outer aluminum base support layer 11 that are in direct contact with the silicon carbide power device. The layers are connected by diffusion welding or vacuum brazing. The heat dissipation fin assembly 2 is fixed to the surface of the aluminum base support layer. The microchannel 3 penetrates the intermediate copper alloy layer 10. The low melting point alloy phase change material 4 in the microchannel 3 is in contact with the high thermal conductivity graphene layer 9.

[0025] In this embodiment: the high thermal conductivity graphene layer 9 directly contacts the device, utilizing the ultra-high thermal conductivity of graphene to quickly dissipate heat from the chip and reduce thermal resistance; the intermediate copper alloy layer 10 provides high-strength support and good thermal conductivity, and the microchannel 3 provides filling space for the phase change material; the aluminum-based support layer is a lightweight support structure, reducing the overall weight, and enabling the heat dissipation substrate 1 to form a layered structure to optimize the heat conduction path. The graphene layer absorbs heat quickly, the copper alloy layer conducts heat uniformly, and the phase change material directly contacts the graphene layer, realizing rapid heat absorption and diffusion, and improving the overall thermal conductivity efficiency of the substrate.

[0026] The thickness of the high thermal conductivity graphene layer 9 is 0.05-0.2 mm, the thickness of the intermediate copper alloy layer 10 is 0.5-1.5 mm, and the thickness of the outer aluminum base support layer 11 is 2-5 mm.

[0027] As a technical optimization of this utility model, the heat-conducting column 8 has a hollow structure and a spiral guide vane 12 is provided inside. The spiral direction of the spiral guide vane 12 is consistent with the airflow direction in the guide cavity 5.

[0028] In this embodiment: the spiral guide vane 12 is aligned with the airflow direction, guiding the airflow along the spiral path and increasing the residence time of the airflow in the guide cavity 5; and the spiral guide vane 12 enhances airflow disturbance, forms turbulence, destroys the boundary layer, increases the gas-solid contact area, improves the heat exchange efficiency between the heat-conducting column 8 and the airflow, and makes the heat dissipate to the external environment more efficiently.

[0029] It should be noted that: the heat-conducting column 8 is set inside the flow-guiding cavity 5. When the airflow enters the flow-guiding cavity 5 from the air inlet 6, it will flow through the surface of the heat-conducting column 8 and the interior of the heat-conducting column 8 (because the heat-conducting column 8 is hollow and has a spiral guide plate 12 inside); the spiral direction of the spiral guide plate 12 is consistent with the airflow direction from the air inlet 6 into the flow-guiding cavity 5. The purpose of this design is to guide the airflow to form a spiral flow inside the heat-conducting column 8, thereby enhancing the heat exchange efficiency between the airflow and the heat-conducting column 8.

[0030] As a technical optimization of this utility model, the inner wall of the flow guide cavity 5 is provided with a nano-aerogel heat insulation layer 13, and a temperature-sensitive shape memory alloy valve 14 is installed at the air inlet 6. The temperature-sensitive shape memory alloy valve 14 is used to adjust the opening of the air inlet 6 according to the temperature change of the heat dissipation substrate 1.

[0031] In this embodiment: the nano-aerogel insulation layer 13 covers the inner wall of the flow channel 5, reducing the influence of the external environment on the temperature inside the cavity and reducing heat loss; the temperature-sensitive shape memory alloy valve 14 automatically adjusts the opening of the air inlet 6 according to the temperature of the heat dissipation substrate 1 (the opening increases when the temperature is high and decreases when the temperature is low); the insulation layer reduces heat loss, and the valve realizes "intelligent air control", increasing the air intake to enhance heat dissipation when the temperature is high and reducing energy consumption when the temperature is low, taking into account both heat dissipation efficiency and energy saving requirements;

[0032] The temperature-sensitive shape memory alloy valve plate 14 (such as nickel-titanium alloy) automatically adjusts the opening degree according to the phase transformation temperature (which can be preset to 60℃ or 100℃): at low temperature, it partially blocks the air inlet 6, and at high temperature, it restores the initial shape and increases the opening degree.

[0033] As a technical optimization of this utility model, the heat dissipation fin group 2 includes at least two layers of parallel fins 15, and a heat dissipation gap 16 is formed between adjacent two layers of fins 15. The width of the heat dissipation gap 16 gradually increases from the air inlet 6 to the air outlet 7.

[0034] In this embodiment: the heat dissipation fin group 2 (with gradually changing gap width) gradually increases the heat dissipation gap 16 from the air inlet 6 to the air outlet 7 to adapt to changes in airflow speed (lower airflow speed at the front end and higher speed at the rear end); to avoid airflow blockage at the front end due to narrow gap, and to accelerate airflow discharge at the rear end due to wide gap, thereby improving the utilization efficiency of the airflow of the fin group 15 and ensuring uniform heat dissipation throughout the entire area.

[0035] As a technical optimization of this utility model, it also includes a semiconductor cooling chip 17 installed on the outside of the heat dissipation fin assembly 2. The cold surface of the semiconductor cooling chip 17 is in contact with the heat dissipation fin assembly 2, and the semiconductor cooling chip 17 is electrically connected to a temperature sensor 18 and a control module 19. The temperature sensor 18 is attached to the position of the chip on the silicon carbide power device, and the control module 19 is located on the edge of the flow channel 5. The temperature sensor 18 is used to detect the junction temperature of the silicon carbide power device, and the control module 19 adjusts the working power of the semiconductor cooling chip 17 according to the data of the temperature sensor 18.

[0036] In this embodiment: the thermoelectric cooler 17 actively cools, directly reducing the temperature of the fin group 15 and enhancing heat dissipation; the temperature sensor 18 monitors the junction temperature of the device in real time and provides data to the control module 19; the control module 19 dynamically adjusts the power of the thermoelectric cooler 17 according to the junction temperature (high power at high temperature, low power or off at low temperature), and the thermoelectric cooler 17 is fixed by thermal grease or thermal adhesive.

[0037] The control module 19 has a built-in fuzzy PID control algorithm, which dynamically adjusts the voltage and current of the semiconductor cooling chip 17 according to the difference between the junction temperature and the preset threshold; temperature sensor 18 (such as thermocouple, NTC thermistor);

[0038] Temperature sensor 18 → control module 19 → thermoelectric cooler 17 form a closed-loop control:

[0039] Temperature sensor 18 monitors the junction temperature of the device in real time and outputs analog or digital signals; control module 19 has a built-in fuzzy PID algorithm to compare the real-time junction temperature with a preset threshold (such as 150℃, set according to device specifications) and calculate the power adjustment amount; control module 19 adjusts the working power of semiconductor cooling chip 17 through PWM (pulse width modulation) or voltage / current regulation circuit. When the junction temperature is higher than the threshold, the cooling power is increased, and when it is lower than the threshold, the power is reduced or turned off to avoid energy waste.

[0040] Working principle and usage process of this utility model:

[0041] The silicon carbide power device generates heat during operation, which is conducted through the graphene layer to the microchannel 3 of the copper alloy layer. The low-melting-point alloy in the microchannel 3 absorbs heat and undergoes a phase change, storing heat and preventing the substrate temperature from rising rapidly. The heat-conducting pillar 8 conducts the heat from the phase change material to the flow channel 5, while the heat from the substrate is transferred to the heat dissipation fin group 2 through the aluminum-based support layer. External air enters the flow channel 5 through the air inlet 6 (the valve adjusts its opening according to the temperature), and the spiral flow guide 12 causes the airflow to turbulently exchange heat with the heat-conducting pillar 8 and the fin group 15. The heat is discharged from the air outlet 7 with the airflow. When the temperature sensor 18 detects that the junction temperature of the device is too high, the control module 19 activates the semiconductor cooling chip 17 to reduce the temperature of the fin group 15 and enhance heat dissipation. After the junction temperature decreases, the cooling power is automatically reduced to save energy.

[0042] In the description of this utility model, it should be understood that the terms "left", "right", "up", "down", "top", "bottom", "front", "back", "inner", "outer", "back", "middle", 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.

[0043] However, the above are merely specific embodiments of this utility model and should not be construed as limiting the scope of implementation of this utility model. Therefore, any substitution of equivalent components or equivalent changes and modifications made in accordance with the scope of protection of this utility model should still fall within the scope of the claims of this utility model.

Claims

1. A heat dissipation mechanism of a silicon carbide power device, comprising a heat dissipation substrate (1) for mounting a silicon carbide power device and a heat dissipation fin group (2) covering above the heat dissipation substrate (1), characterized in that: The heat dissipation substrate (1) is internally provided with microchannels (3) staggered in a grid shape, and the microchannels (3) are filled with low-melting-point alloy phase change materials (4); the heat dissipation fin group (2) and the heat dissipation substrate (1) are provided with a flow guide cavity (5), the flow guide cavity (5) is provided with an air inlet (6) and an air outlet (7) in communication with the outside, and the flow guide cavity (5) is provided with a heat conduction column (8) in thermal coupling with the microchannels (3).

2. The heat dissipation mechanism of a silicon carbide power device according to claim 1, wherein: The heat dissipation substrate (1) comprises a high-thermal-conductivity graphene layer (9) in direct contact with the silicon carbide power device, an intermediate copper alloy layer (10), and an external aluminum-based support layer (11), and each layer is connected by diffusion welding or vacuum brazing process; the heat dissipation fin group (2) is fixed on the surface of the aluminum-based support layer, the microchannels (3) penetrate through the intermediate copper alloy layer (10), and the low-melting-point alloy phase change materials (4) in the microchannels (3) are in contact with the high-thermal-conductivity graphene layer (9).

3. The heat dissipation mechanism of a silicon carbide power device according to claim 1, wherein: The heat conduction column (8) is a hollow structure, and a spiral flow guide fin (12) is arranged inside the heat conduction column (8), and the spiral direction of the spiral flow guide fin (12) is consistent with the airflow direction in the flow guide cavity (5).

4. The heat dissipation mechanism of a silicon carbide power device according to claim 1, wherein: The inner wall of the flow guide cavity (5) is provided with a nano-aerogel thermal insulation layer (13), and a temperature-sensitive shape memory alloy valve plate (14) is installed at the air inlet (6), and the temperature-sensitive shape memory alloy valve plate (14) is used to adjust the opening of the air inlet (6) according to the temperature change of the heat dissipation substrate (1).

5. The heat dissipation mechanism of a silicon carbide power device according to claim 1, wherein: The heat dissipation fin group (2) comprises at least two layers of fins (15) arranged in parallel, and a heat dissipation gap (16) is formed between the two adjacent layers of fins (15), and the width of the heat dissipation gap (16) gradually increases from the air inlet (6) to the air outlet (7).

6. The heat dissipation mechanism of a silicon carbide power device according to claim 1, wherein: Further comprising a semiconductor refrigeration sheet (17) installed on the outside of the heat dissipation fin group (2), the cold surface of the semiconductor refrigeration sheet (17) is attached to the heat dissipation fin group (2), and the semiconductor refrigeration sheet (17) is electrically connected with a temperature sensor (18) and a control module (19), the temperature sensor (18) is attached to the position of the chip of the silicon carbide power device, and the control module (19) is arranged on the frame of the flow guide cavity (5), the temperature sensor (18) is used to detect the junction temperature of the silicon carbide power device, and the control module (19) adjusts the working power of the semiconductor refrigeration sheet (17) according to the data of the temperature sensor (18).

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