High-power semiconductor power device water-cooling structure and design method thereof

Abstract

The application discloses a water cooling structure of a high-power semiconductor power device, which comprises a high-power semiconductor power device chip plate, a plurality of LED chips are arranged on the high-power semiconductor power device chip plate, and a heat spreading sheet is arranged on each LED chip; a water cooling structure is arranged on one side of the high-power semiconductor power device chip plate; the water cooling structure comprises a water inlet pipe, a front section of a serpentine pipe, a rear section of the serpentine pipe and a water outlet pipe; the water inlet pipe is connected with the front section of the serpentine pipe; the front section of the serpentine pipe and the rear section of the serpentine pipe are integrally formed; the rear section of the serpentine pipe is connected with the water outlet pipe; cooling liquid can flow out from the water outlet pipe after sequentially passing through the water inlet pipe, the front section of the serpentine pipe and the rear section of the serpentine pipe; and the outer surface of the front section of the serpentine pipe and the outer surface of the rear section of the serpentine pipe are in contact with the heat spreading sheets. The application has the advantages that the internal temperature of the chip can be effectively reduced, and the uniformity of the temperature of the chip can be ensured.

Description

Technical Field

[0001] This invention relates to the technical field of water-cooling equipment, and more particularly to the structure and design of water-cooling circuits for circuit boards. Specifically, it relates to the water-cooling structure and design method of high-power semiconductor power devices. Background Technology

[0002] With the continuous development of LED technology, the power handling capacity of LEDs in the same package size is constantly increasing, with the highest power density reaching over 120W / cm². Therefore, the heat dissipation problem of LEDs is becoming increasingly prominent in LED applications. To address the heat dissipation requirements under high power density, domestic and international industries have mainly explored aspects such as chip design, manufacturing methods, and external heat sinks. For example, in terms of luminous efficacy, efforts are being made to continuously increase the efficiency of converting electrical energy into light energy and reduce initial heat generation; in terms of materials, new materials for substrates and heat sinks are being continuously developed; in terms of packaging architecture, new architectures are being proposed and continuously optimized, such as flip-chip architecture and vertical chip architecture; and in terms of system heat sinks, efforts are being made to continuously improve the effectiveness of existing thermal management measures or apply new heat dissipation methods to enable the rapid and efficient transfer of heat from the LED to the air.

[0003] Because LEDs have low photoelectric efficiency, typically below 30%, over 70% of their electrical energy is released as heat. Optimizing chip design to increase the efficiency of energy conversion to light and reduce the proportion of energy converted to heat can effectively eliminate heat dissipation hazards from within. External heat dissipation technologies mainly include active and passive cooling. Active cooling technologies include air cooling, water cooling, heat pipes, micro-spray cooling, and thermoelectric cooling, while passive cooling technologies mainly include finned cooling. Water cooling has advantages such as low structural complexity and strong heat exchange capacity, typically improving efficiency by more than 10 times compared to conventional air cooling, while also significantly reducing noise. The heat generated by the LED chip is conducted to the water-cooled housing, and then carried away by water circulation. At the rear of the water circuit, air convection dissipates the heat carried in the water into the environment. Currently, China has achieved significant success in water cooling technology, and research on water cooling systems for LEDs has been widely applied in engineering.

[0004] The design of a heat dissipation system for high-power semiconductor devices involves selecting appropriate heat dissipation methods and designing a reasonable and efficient heat dissipation system to keep the LED operating at a certain temperature, ensuring the reliability and safety of the product. Considering various factors, the heat dissipation design of high-power semiconductor devices should generally meet the following requirements: (1) The LED chip temperature should be kept within a reasonable range. Temperature is a key parameter and technical indicator for measuring the heat dissipation performance of LEDs, and it has a crucial impact on the stability, photoelectric parameters, and lifespan of LED devices. (2) The heat sink should meet certain requirements regarding installation space, weight, and cost. Reasonably designing the shape, size, and installation method of the heat sink can effectively improve heat dissipation efficiency and enhance the performance of the LED.

[0005] Effective LED heat dissipation management is crucial for rapidly dissipating heat accumulated in the PN junction, thereby quickly reducing the junction temperature. This directly impacts parameters such as luminous efficiency, lifespan, and the overall performance of the light source. This paper uses the computational fluid dynamics software Fluen to simulate and analyze the design of a water-cooling system for high-power airborne LEDs. Through reasonable optimization, the internal temperature of the chip is effectively reduced while ensuring temperature uniformity, thus guaranteeing the efficient and stable operation of the airborne LED light source. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a water-cooling structure for high-power semiconductor power devices and its design method, which addresses the shortcomings of the prior art.

[0007] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0008] A water-cooling structure for high-power semiconductor power devices is characterized by comprising a high-power semiconductor power device chip board, on which a plurality of LED chips are arranged, each LED chip being fitted with a heat sink; a water-cooling structure is provided on one side of the high-power semiconductor power device chip board; the water-cooling structure includes an inlet pipe, a front serpentine tube, a rear serpentine tube, and an outlet pipe; the inlet pipe is connected to the front serpentine tube; and the front and rear serpentine tubes... The system is integrally molded, with the rear section of the serpentine tube connected to the outlet pipe. Coolant can flow out from the outlet pipe after passing through the inlet pipe, the front section of the serpentine tube, and the rear section of the serpentine tube in sequence. The outer surface of the front section of the serpentine tube is in close contact with each heat exchanger, and the outer surface of the rear section of the serpentine tube is in close contact with each heat exchanger. The sum of the tube length between the point of contact between the front section of the serpentine tube and the front end of the front section of the serpentine tube and the tube length between the point of contact between the rear section of the serpentine tube and the front end of the front section of the serpentine tube is equal to the sum of the tube lengths of the front section of the serpentine tube and the rear section of the serpentine tube.

[0009] To optimize the above technical solution, the specific measures also include:

[0010] The overall temperature difference of the aforementioned LED chips does not exceed 10℃.

[0011] The LED chip mounted on the aforementioned high-power semiconductor power device chip board is a 7.5W high-power LED chip.

[0012] The aforementioned inlet pipe, front serpentine pipe, rear serpentine pipe, and outlet pipe are all aluminum pipes.

[0013] The aforementioned high-power semiconductor power device chip board is a copper plate.

[0014] The coolant mentioned above is water.

[0015] The design method for water-cooled structures of high-power semiconductor power devices includes the following steps:

[0016] Step 1: Based on the actual model dimensions of the high-power semiconductor power device chip board and simplifying them, obtain the three-dimensional geometric model of the high-power semiconductor power device chip board;

[0017] Step 2: Add a 3D model of the water-cooling structure to the 3D geometric model of the high-power semiconductor power device chip board, forming a combined 3D model of the chip board and water-cooling structure.

[0018] Step 3: Mesh the 3D model of the chip board and water-cooling structure combination, and import the mesh into the fluid simulation software.

[0019] Step 4: Set the heat dissipation coefficient of the LED chips on the chip board, as well as the fluid medium, thermal conductivity, and flow velocity parameters of the water-cooling structure. In the fluid simulation software, solve for the temperature of the grid occupied by the LED chips in the 3D model of the chip board and water-cooling structure combination, and calculate the total heat dissipation when the overall temperature difference of each LED chip does not exceed the threshold.

[0020] Step 5: Modify the 3D model of the water-cooling structure in Step 2 to create a new 3D model of the chip board and water-cooling structure combination. Repeat Steps 3 to 5 a predetermined number of times.

[0021] Step 6: Select the 3D model of the chip board and water cooling structure combination with the highest total heat dissipation, and set the water cooling structure of the high-power semiconductor power device chip board according to this model.

[0022] In step one above, the size of the high-power semiconductor power device chip board is 1mm×1mm×0.05mm, and 10 7.5W high-power LED chips are set on the chip board.

[0023] In step one above, the three-dimensional geometric model of the high-power semiconductor power device chip board is obtained by referring to the actual model size of the high-power semiconductor power device chip board and ignoring the reflection and radiation effects of the lamp cover.

[0024] The fluid simulation software mentioned above is FLUENT.

[0025] The present invention has the following advantages:

[0026] 1. The present invention relates to a water-cooling structure for high-power semiconductor power devices. A water-cooling structure is provided on one side of a high-power semiconductor power device chip board. The water-cooling structure includes an inlet pipe, a front serpentine tube, a rear serpentine tube, and an outlet pipe. The inlet pipe is connected to the front serpentine tube, and the front and rear serpentine tubes are integrally formed. The rear serpentine tube is connected to the outlet pipe. Coolant can flow out from the outlet pipe after passing through the inlet pipe, the front serpentine tube, and the rear serpentine tube in sequence. The outer surface of the front serpentine tube is in contact with each LED chip, and the outer surface of the rear serpentine tube is in contact with each LED chip. The sum of the tube length between the point of contact between each LED chip and the front end of the front serpentine tube and the tube length between the point of contact between the rear serpentine tube and the front end of the front serpentine tube is equal to the sum of the tube lengths of the front and rear serpentine tubes. The advantage of this design is that each LED chip has two serpentine tubes for cooling, one in the front and one in the back. The serpentine tubes further in front have a better cooling effect, while those further back have a worse cooling effect. The two serpentine tubes allocated to each LED chip are mixed with different quality levels, which effectively reduces the internal temperature of the chip and ensures the uniformity of the chip temperature, thus helping to ensure the efficient and stable operation of the airborne LED light source.

[0027] 2. This invention provides a design method for a water-cooled structure of a high-power semiconductor power device. This method can quickly and effectively calculate the cooling effect of water-cooled structures of different shapes on each chip and the temperature difference of each chip. Finally, the three-dimensional model of the chip board and water-cooled structure combination with the highest total heat dissipation is selected. The water-cooled structure of the high-power semiconductor power device chip board is set according to this model, so as to effectively reduce the internal temperature of the chip and ensure the uniformity of chip temperature. Attached Figure Description

[0028] Figure 1 : A schematic diagram of the water-cooling structure of the high-power semiconductor power device of the present invention;

[0029] Figure 2 Schematic diagram of a high-power semiconductor power device chip board;

[0030] Figure 3 Schematic diagram of a single serpentine channel heat dissipation structure;

[0031] Figure 4 Diagram showing the heat dissipation effect of a single serpentine channel;

[0032] Figure 5 Schematic diagram of a dual serpentine channel heat dissipation structure;

[0033] Figure 6Diagram showing the cooling effect of a dual-serpentine channel.

[0034] The attached diagram is labeled as follows: 1. High-power semiconductor power device chip board; 11. LED chip; 2. Water-cooled structure; 21. Water inlet pipe; 22. Front section serpentine tube; 23. Rear section serpentine tube; 24. Water outlet pipe; 3. Heat sink. Detailed Implementation

[0035] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0036] The design method for the water-cooled structure of high-power semiconductor power devices of the present invention obtains a three-dimensional geometric model of the high-power semiconductor power device chip board by referring to the actual model size of the chip board. The airborne high-power LED module adopts a forced water cooling heat dissipation method. Before numerical simulation, the actual model size is referenced and simplified to obtain a three-dimensional geometric model. The light source of the airborne high-power LED module is analyzed using a 7.5W high-power LED from CREE as an example, with a chip size of 1mm × 1mm × 0.05mm, a substrate size of 1mm × 1mm × 0.2mm, and 10 LED beads arranged in an array.

[0037] The flow in an airborne high-power LED water cooling system is subject to the laws of conservation of physical properties, including the laws of conservation of mass, momentum, and energy.

[0038] (1) Mass conservation equation: The increase in mass within the control body equals the mass flowing into the control body.

[0039]

[0040] Where ρ is density and t is time. It is a velocity vector.

[0041] (2) Momentum conservation equations, also known as motion equations or Navier-Stokes equations, state that the increase in momentum within the control body equals the inflow momentum plus the impulse of surface forces plus the impulse of volume forces.

[0042] In the x-direction:

[0043]

[0044] In the y-direction:

[0045]

[0046] In the z-direction:

[0047]

[0048] Where μ is the dynamic viscosity, S u S v and S w It is the generalized source term of the momentum conservation equation.

[0049] (3) Energy conservation equation: The change in energy within the body = energy inflow + work done by surface forces + work done by volume forces + heat transferred in.

[0050]

[0051] Where T is temperature, k is the heat transfer coefficient of the fluid, and S T As the internal heat source of the fluid, C P It is specific heat capacity.

[0052] In the above equations, when the time term is 0, it is a steady-state simulation; when the time term is not 0, it is a transient simulation.

[0053] The simulation only considers the heat dissipation system and ignores the reflection and radiation effects of components such as lampshades to simplify the model.

[0054] A three-dimensional model of a water-cooling structure is set on a three-dimensional geometric model of a high-power semiconductor power device chip board, forming a combined three-dimensional model of the chip board and the water-cooling structure.

[0055] After the geometric modeling process is completed on the PROE platform, the 3D model of the chip board and water-cooled structure combination will be imported into the mesh generation platform ANSYS ICEM. To improve calculation accuracy and reduce calculation errors, the mesh will be refined. Subsequently, the mesh will be generated to approximately 2 million elements. The generated mesh will then be imported into FLUENT 14.5, a double-precision solver will be selected, and the mesh will be checked to ensure that the minimum element volume is not less than 0, i.e., there are no negative volume meshes.

[0056] Boundary conditions were set, including the heat generation coefficient of the LED chip on the chip board, and the parameters of the fluid medium, thermal conductivity, and flow velocity in the water-cooled structure. The fluid medium was water, which is incompressible during flow. The pressure-velocity coupling was implemented using the SIMPLIC algorithm with a second-order accuracy upwind scheme, and solved using the computational fluid dynamics software FLUENT. The boundary conditions involved in the water-cooled system model of the high-power semiconductor power device included inlet and outlet boundary conditions and wall boundary conditions. In the numerical simulation, the inlet boundary condition was set as a velocity inlet with a velocity of 1 m / s, and the LED chip temperature was 300 K. The outlet boundary condition was set as a pressure outlet, and the external relative pressure was set to 0. The total power was 7.5 W, with heat power applied to the chip. The solid materials and thermal conductivity of each part of the model are shown in Table 1.

[0057] Table 1. Materials and Thermal Conductivity of Each Component

[0058] name Material Thermal conductivity w*m-1*k-1 chip silicon 124 substrate copper 398 heat sink aluminum 220

[0059] Results and Analysis

[0060] Heat dissipation simulation was performed based on the set initial values. The water path adopted a single serpentine channel, and its heat dissipation effect was as follows: Figure 3-4 As shown, by Figure 4 It is known that the highest temperature of an LED chip is 395K. Figure 3 and 4 It can be observed that the temperature of the entire LED chip gradually increases from the inlet to the outlet, which is consistent with actual laws. The temperature of the first chip in the direction of water flow is the lowest. As the water flows forward, it absorbs heat generated by the LED module on the upper part of the heat sink. The longer the flow path, the higher the temperature absorbed, so that the highest temperature is concentrated at the last chip in the direction of water flow, and the temperature difference between the chips is large.

[0061] Heat dissipation simulation was performed based on the set initial values. The water channel adopted a double serpentine channel, and the structure diagram is as follows. Figure 5 As shown, the heat dissipation effect is as follows Figure 6 As shown, by Figure 6 It can be seen that the highest temperature of the heat sink is 385K. From the temperature curve, it can be found that the entire water-cooled heat sink has dual pipes, and these dual pipes can cool the LED chips evenly. That is, each LED chip will have a pipe with a low temperature and a pipe with a high temperature. The overall temperature difference between the LED chip modules is 10℃, which is significantly reduced. This proves that the heat dissipation effect of the dual serpentine flow channel solution is significantly improved.

[0062] However, setting only dual serpentine channels will cause excessive temperature differences between different locations within the same LED chip, and the temperature of the part in contact with the front serpentine tube 22 will be significantly lower than the temperature of the part in contact with the rear serpentine tube 23.

[0063] The present invention sets a heat spreader 3 on the LED chip, so that the temperature of the LED chip is conducted to the heat spreader 3, and then the heat is dissipated by the front serpentine tube 22 and the rear serpentine tube 23. The temperature difference is relatively large on the heat spreader 3. After the conduction of the heat spreader 3, the temperature difference acting on the LED chip can be controlled within 10°.

[0064] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A water-cooled structure for high-power semiconductor power devices, characterized by: The system includes a high-power semiconductor power device chip board (1), on which a plurality of LED chips (11) are arranged, and each LED chip (11) is fitted with a heat sink (3). A water-cooling structure (2) is provided on one side of the high-power semiconductor power device chip board (1). The water-cooling structure (2) includes an inlet pipe (21), a front serpentine pipe (22), a rear serpentine pipe (23), and an outlet pipe (24). The inlet pipe (21) is connected to the front serpentine pipe (22). The front serpentine pipe (22) and the rear serpentine pipe (23) are integrally formed. (23) is connected to the outlet pipe (24). The coolant can flow out from the outlet pipe (24) after passing through the inlet pipe (21), the front section of the serpentine pipe (22) and the rear section of the serpentine pipe (23) in sequence. The outer surface of the front section of the serpentine pipe (22) is in contact with each heat exchange plate (3). The outer surface of the rear section of the serpentine pipe (23) is in contact with each heat exchange plate (3). The sum of the length between the point of contact between the front section of the serpentine pipe (22) and the front end of the front section of the serpentine pipe (22) and the length between the point of contact between the rear section of the serpentine pipe (23) and the front end of the front section of the serpentine pipe (22) is equal to the sum of the lengths of the front section of the serpentine pipe (22) and the rear section of the serpentine pipe (23).

2. The water-cooled structure for high-power semiconductor power devices according to claim 1, characterized in that: The overall temperature difference of each LED chip (11) does not exceed 10℃.

3. The water-cooling structure for high-power semiconductor power devices according to claim 1, characterized in that: The LED chip mounted on the high-power semiconductor power device chip board (1) is a 7.5W high-power LED chip.

4. The water-cooled structure for high-power semiconductor power devices according to claim 1, characterized in that: The inlet pipe (21), the front serpentine pipe (22), the rear serpentine pipe (23), and the outlet pipe (24) are all aluminum pipes.

5. The water-cooled structure for high-power semiconductor power devices according to claim 1, characterized in that: The high-power semiconductor power device chip board (1) is a copper plate.

6. The water-cooled structure for high-power semiconductor power devices according to claim 1, characterized in that: The coolant is water.

7. The design method for a water-cooled structure of a high-power semiconductor power device as described in any one of claims 1-6, characterized in that: Includes the following steps: Step 1: Based on the actual model dimensions of the high-power semiconductor power device chip board and simplifying them, obtain the three-dimensional geometric model of the high-power semiconductor power device chip board; Step 2: Add a 3D model of the water-cooling structure to the 3D geometric model of the high-power semiconductor power device chip board, forming a combined 3D model of the chip board and water-cooling structure. Step 3: Mesh the 3D model of the chip board and water-cooling structure combination, and import the mesh into the fluid simulation software. Step 4: Set the heat generation coefficient of the LED chips on the chip board, as well as the fluid medium, thermal conductivity, and flow velocity parameters of the water-cooling structure. Solve the temperature of the grid occupied by the LED chips in the three-dimensional model of the chip board and water-cooling structure combination in the fluid simulation software, and calculate the total heat dissipation of each LED chip (11) under the condition that the overall temperature difference does not exceed the threshold. Step 5: Modify the 3D model of the water-cooling structure in Step 2 to create a new 3D model of the chip board and water-cooling structure combination. Repeat Steps 3 to 5 a predetermined number of times. Step 6: Select the 3D model of the chip board and water cooling structure combination with the highest total heat dissipation, and set the water cooling structure of the high-power semiconductor power device chip board according to this model.

8. The design method for a water-cooled structure of a high-power semiconductor power device according to claim 7, characterized in that: In step one, the high-power semiconductor power device chip board has a size of 1mm×1mm×0.05mm, and 10 7.5W high-power LED chips are set on the chip board.

9. The design method for a water-cooled structure of a high-power semiconductor power device according to claim 7, characterized in that: In step one, referring to the actual model size of the high-power semiconductor power device chip board, and ignoring the reflection and radiation effects of the lampshade, a three-dimensional geometric model of the high-power semiconductor power device chip board is obtained.

10. The design method for a water-cooled structure of a high-power semiconductor power device according to claim 7, characterized in that: The fluid simulation software mentioned is FLUENT.

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