An efficient double-layer heat dissipation structure for a power module and a power module having the structure

Abstract

The present invention discloses a high-efficiency double-layer heat dissipation structure for a power module and a power module having the structure, which relates to the technical field of heat dissipation devices. The structure includes a heat dissipation structure that is installed at the bottom of the power module and fits therewith. The heat dissipation structure includes a first heat dissipation layer, a guiding partition plate, and a second heat dissipation layer formed in sequence from top to bottom. It also includes a cooling medium inlet communicating with the cavity in the second heat dissipation layer and a cooling medium outlet communicating with the cavity in the first heat dissipation layer. At the same time, at least one guiding hole is provided on the guiding plate corresponding to the position of the chip. In the present invention, the cooling medium of the high-efficiency double-layer heat dissipation structure of the power module enters the second heat dissipation layer through the heat dissipation medium inlet, then flows through the guiding partition plate into the first heat dissipation layer. Through the guiding action of the guiding partition plate, heat dissipation is carried out in a targeted manner at the position below the power module chip. The temperature of the heat dissipation medium flowing through below each chip is consistent, realizing balanced and high-efficiency heat dissipation of the power module.

Description

Technical Field

[0001] The present invention relates to the technical field of heat dissipation devices, and particularly to a high-efficiency double-layer heat dissipation structure for a power module and a power module having the same structure. Background Art

[0002] Power electronics technology occupies a very important position in today's rapidly developing industrial field. As a representative of power electronics technology, power electronic power modules have been widely used in industries such as electric vehicles, photovoltaic power generation, wind power generation, and industrial frequency conversion. With the rise of China's industry, power electronic power modules have a broader market prospect.

[0003] With the continuous increase in the demand for power modules, higher requirements are also put forward for the high efficiency and high power density of power modules. Especially with the rapid development of silicon carbide (SiC) modules, compared with traditional silicon-based power modules, the power density has been greatly improved. However, the working temperature of the chips has not been significantly increased at present and remains around 175°C, which poses higher requirements for the heat dissipation of power modules.

[0004] In addition, high-power modules often need to use multiple IGBT or MOSFET chips in parallel. The inconsistent heat dissipation conditions between chips are likely to cause uneven current sharing, resulting in overheating and damage of individual chips, seriously affecting the reliability of power modules.

[0005] In the prior art, the design of the heat dissipation structure often targets the entire power module. For example, Figure 1 and Figure 2 As shown, in existing heat dissipation devices, the heat dissipation structure is mainly directly placed at the bottom of the power module, and the heat is taken away by the flowing coolant. However, for the cooling structure of parallel chips, there are large differences in the temperatures at the corresponding heat dissipation positions at the bottoms of different chips. The temperature at the position far from the coolant inlet is higher, and the heat dissipation effect of the corresponding chips is worse. It is impossible to achieve balanced control of chips at different positions. Summary of the Invention

[0006] In view of the above technical problems, the present invention overcomes the disadvantages of the prior art and provides a high-efficiency double-layer heat dissipation structure for a power module and a power module having the same structure.

[0007] To solve the above technical problems, the present invention provides a high-efficiency double-layer heat dissipation structure for a power module and a power module having the same structure.

[0008] Technical effect: By setting a first heat dissipation layer, a guide baffle, and a second heat dissipation layer, the cooling medium of the power module's efficient double-layer heat dissipation structure enters the second heat dissipation layer through the heat dissipation medium inlet, and then flows through the guide baffle into the first heat dissipation layer. Through the guiding effect of the guide baffle, the position below the power module chip is dissipated in a direction. The temperature of the heat dissipation medium flowing under each chip is consistent. The size and position of the guide hole in the guide baffle can be set to control the direction and flow of the cooling medium entering the first heat dissipation layer, thereby achieving balanced and efficient heat dissipation of the power module.

[0009] The technical solution further defined in the present invention is: a high-efficiency double-layer heat dissipation structure of a power module, including a power unit with a plurality of parallel chips, a heat dissipation structure fitted therewith is installed at the bottom of the power unit, the heat dissipation structure includes a first heat dissipation layer, a guide partition and a second heat dissipation layer formed in sequence from top to bottom, and also includes

[0010] a first cooling medium inlet, connected to the cavity in the second heat dissipation layer, for injecting cooling medium;

[0011] A cooling medium outlet is connected to the cavity in the first heat dissipation layer and is used to discharge the cooling medium after heat exchange;

[0012] At least one guide hole is provided on the guide plate corresponding to the chip position, for connecting the first heat dissipation layer with the cavity in the second heat dissipation layer.

[0013] Furthermore, a second cooling medium inlet connected to the cavity is provided on a side of the first heat dissipation layer away from the cooling medium outlet.

[0014] In the aforementioned high-efficiency double-layer heat dissipation structure for a power module, at least one side of each guide hole is provided with a guide plate distributed perpendicular to the flow direction of the cooling medium, and an area corresponding to the chip is formed between adjacent guide plates.

[0015] In the aforementioned high-efficiency double-layer heat dissipation structure for a power module, the length of the guide plate is smaller than the width of the cavity in the first heat dissipation layer, and a channel for the circulation of the cooling medium is reserved between the guide plate and the inner side of the first heat dissipation layer.

[0016] In the aforementioned high-efficiency double-layer heat dissipation structure for a power module, the guide holes are in any one of a circular, elliptical, oblong, rectangular or strip shape.

[0017] In the aforementioned high-efficiency double-layer heat dissipation structure for a power module, a plurality of guide holes are provided corresponding to each chip area, and the plurality of guide holes in each chip area form a multi-hole heat dissipation set.

[0018] The present invention also provides a power module with a double-layer heat dissipation structure, which includes a power unit and a double-layer heat dissipation structure connected thereto. The power unit is provided with a plurality of chips arranged in an array, and the chips are powered by a positive electrode, a negative electrode, and an output electrode provided on the power unit; the power unit is further provided with a plurality of signal electrodes, and the signal electrodes are electrically connected to the chips; the double-layer heat dissipation structure is the high-efficiency double-layer heat dissipation structure of the power module proposed by the present invention.

[0019] The beneficial effects of the present invention are as follows:

[0020] (1) In the present invention, the existing heat dissipation structure is controlled in zones, a first heat dissipation layer, a guiding partition board, and a second heat dissipation layer are provided, and guiding holes are provided on the guiding partition board; through the guiding function of the guiding partition board, heat dissipation is directed to the position below the chips of the power module, and the temperature of the heat dissipation medium flowing through below each chip is the same, realizing balanced and efficient heat dissipation of the power module;

[0021] (2) In the present invention, by setting the shape, size, quantity, and position of the guiding holes in the guiding partition board, the direction and flow rate of the cooling medium entering the first heat dissipation layer can be controlled, realizing differential control of chips of different sizes and power levels, and improving the heat dissipation efficiency of the module;

[0022] (3) In the present invention, by providing a diversion plate in the first heat dissipation layer, the cooling medium flowing into the first heat dissipation layer is directed to flow out to the cooling medium outlet, avoiding the high-temperature cooling medium from flowing through the high-temperature area below the chips repeatedly. Description of the Drawings

[0023] Figure 1 It is a schematic diagram of the heat dissipation structure in the prior art;

[0024] Figure 2 It is a schematic diagram of the flow direction of the cooling medium of the heat dissipation structure in the prior art;

[0025] Figure 3 It is an overall external structure diagram of Embodiment 1;

[0026] Figure 4 It is an exploded view of the structure of Embodiment 1;

[0027] Figure 5 It is a schematic diagram of the flow direction of the cooling medium of Embodiment 1;

[0028] Figure 6 It is a schematic diagram of the temperature distribution in the working state of the heat dissipation structure in the prior art;

[0029] Figure 7 It is a schematic diagram of the temperature distribution in the working state of Embodiment 1;

[0030] Figure 8 It is a layout diagram of the corresponding power module chips in Embodiment 1;

[0031] Figure 9 This is a topological diagram of the power module circuit corresponding to Example 1;

[0032] Figure 10 This is a schematic diagram of the current when the upper bridge arm of the power module in Example 1 is working;

[0033] Figure 11 This is a schematic structural diagram of Example 2;

[0034] Figure 12 is a cross-sectional view of Example 2;

[0035] Figure 13 is a cross-sectional view of Example 3;

[0036] Figure 14 Schematic diagram of cooling medium flow in Example 3;

[0037] Figure 15 is a cross-sectional view of Example 4;

[0038] Figure 16 The figure is a cross-sectional view of Example 5;

[0039] Figure 17 The figure is a cross-sectional view of Example 6.

[0040] Among them: 1. Power unit; 11. Chip; 12. Positive electrode; 13. Negative electrode; 14. Output electrode; 15. Signal electrode; 2. First heat dissipation layer; 21. Cooling medium outlet; 22. Second cooling medium inlet; 3. Guide partition; 4. Second heat dissipation layer; 41. First cooling medium inlet; 5. Guide hole; 6. Guide plate. DETAILED DESCRIPTION

[0041] To make the objectives, technical solutions, and advantages of the present invention more apparent, a detailed description is given below in conjunction with the accompanying drawings and specific embodiments. The following description sets forth many specific details to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0042] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only implementation methods.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this invention belongs. The terms used in the description of the present invention herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention.

[0044] A high-efficiency double-layer heat dissipation structure of a power module provided in this embodiment has a structure as Figure 3 and Figure 4 shown, and includes a power unit 1 with a plurality of parallel chips 11. A heat dissipation structure is mounted at the bottom of the power unit 1 and is in fit with it. The heat dissipation structure includes a first heat dissipation layer 2, a guiding partition 3, and a second heat dissipation layer 4 formed in sequence from top to bottom.

[0045] Among them, cavities are formed in both the first heat dissipation layer 2 and the second heat dissipation layer 4 in a hollow manner. A first cooling medium inlet 41 is provided on the left side surface of the second heat dissipation layer 4, and the first cooling medium inlet 41 communicates with the cavity in the second heat dissipation layer 4 for injecting a cooling medium; a cooling medium outlet 21 is provided on the right side surface of the first heat dissipation layer 2, and the cooling medium outlet 21 communicates with the cavity in the first heat dissipation layer 2 for discharging the heat-exchanged cooling medium.

[0046] In addition, at least one guiding hole 5 is formed in the guiding plate corresponding to the position of the chip 11. In this embodiment, there are four guiding holes 5, which are used to communicate the cavities in the first heat dissipation layer 2 and the second heat dissipation layer 4. The guiding holes 5 in this embodiment are circular.

[0047] After being set like this, the direction and flow rate of the cooling medium entering the first heat dissipation layer 2 can be controlled by setting the shape, size, quantity, and position of the guiding holes 5 in the guiding partition 3, so as to achieve differential control of chips 11 with different sizes and power levels and improve the heat dissipation efficiency of the module.

[0048] The main process is as follows: The cooling medium entering the second heat dissipation layer 4 is shunted through a plurality of guiding holes 5, and after being divided into several strands of isothermal cooling media, each strand of cooling medium is uniformly guided to the corresponding chip 11 for cooling to ensure that the cooling effect of each chip 11 is the same.

[0049] As Figure 5 shown, the cooling medium flows into the second heat dissipation layer 4 from the first cooling medium inlet 41, then flows into the first heat dissipation layer 2 through the guiding holes 5 of the guiding partition 3, and dissipates heat directly below the chip 11 through the guiding action of the guiding holes 5 to ensure the consistency of the temperature directly below the chip 11, and finally flows out through the cooling medium outlet 21.

[0050] As Figure 6 and Figure 7 shown, the comparison of temperature changes between the prior art and the present invention can be seen. According to the thermal resistance formula R th =ΔT / Ptot , R th is the thermal resistance of the single chip, P tot is the power dissipation of a single chip. Theoretically, the thermal resistance and power dissipation of the same chip are almost the same. ΔT is the difference between the junction temperature of the chip and the temperature of the heat sink at the corresponding position (ΔT=T j -T s ), radiator temperature T s The higher the chip junction temperature T j The higher the temperature, the more likely it is that individual chips will fail prematurely. In the present invention, directional control of the cooling medium can be achieved so that the temperature of the cooling medium flowing under the multiple parallel chips is T H The size and position of the guide holes can be controlled to adjust the flow rate and ensure the temperature consistency under the chip.

[0051] The present invention also provides a power module with a double-layer heat dissipation structure, such as Figures 8 - 10 As shown, it includes a power unit 1, on which are provided a plurality of chips 11 arranged in an array, and the chip 11 is powered by a positive electrode 12, a negative electrode 13 and an output electrode 14 provided on the power unit 1; the power unit 1 is also provided with a plurality of signal electrodes 15, and the signal electrodes 15 are electrically connected to the chip 11; the power unit 1 is connected to a high-efficiency double-layer heat dissipation structure of a power module as in any one of the above embodiments.

[0052] The positive electrode P and negative electrode N of the power module are located on one side, and the output electrode OUT and signal electrodes (G1 / E1 / G2 / E2) are located on the other side. The module is a multi-chip parallel half-bridge topology circuit structure, with the upper bridge arm located on the output electrode side and the lower bridge arm located on the positive and negative electrode side. Each bridge arm consists of 4 MOSFET chips, and the chips are arranged in sequence from left to right. Figure 8 This is a current diagram when the upper bridge arm of the power module is turned on. I / 2 of the current flows into each of the two positive electrodes. Ideally, each chip bears 1 / 4 of the circuit current. The chip parameters are completely consistent, and the power dissipation generated by each chip is consistent.

[0053] The cooling medium flows from the inlet through the heat dissipation layer directly to the outlet, and the cooling medium passes under the chips CHIP1, CHIP2, CHIP3, and CHIP4 in turn. Due to the heating effect of the chip dissipation power, the cooling medium temperature gradually increases, T S1 <T S2 < T S3 < T S4 , thermal resistance formula R th =ΔT / P tot , if the chip dissipates the same power, the junction temperature T j1 < T j2 < T j3 < T j4, long-term inconsistent junction temperature can easily cause premature failure of individual chips.

[0054] The present invention sets a first heat dissipation layer 2, a guide baffle 3, and a second heat dissipation layer 4, so that the cooling medium of the power module's efficient double-layer heat dissipation structure enters the second heat dissipation layer 4 through the first cooling medium inlet 41, and then flows through the guide baffle 3 into the first heat dissipation layer 2. Through the guiding effect of the guide baffle 3, the position below the power module chip 11 is directionally dissipated. The temperature of the heat dissipation medium flowing under each chip 11 is consistent. The size and position of the guide hole 5 in the guide baffle 3 can be set to control the direction and flow of the cooling medium entering the first heat dissipation layer 2, thereby achieving balanced and efficient heat dissipation of the power module.

[0055] Example 2, a high-efficiency double-layer heat dissipation structure for a power module, differs from Example 1 in that: Figure 11 and Figure 12 As shown, the cooling medium inlet can also be provided on both the first heat dissipation layer 2 and the second heat dissipation layer 4 , that is, the second cooling medium inlet 22 is provided at a corresponding position on the first heat dissipation layer 2 .

[0056] The second cooling medium inlet 22 of the first heat dissipation layer 2 can be provided to prevent a dead water area from forming in a local cavity of the heat dissipation layer.

[0057] Example 3, a high-efficiency double-layer heat dissipation structure for a power module, differs from Example 2 in that: Figure 13 As shown, by providing a guide plate 6 on the first heat dissipation layer 2 , the cooling medium flowing into the first heat dissipation layer 2 is directed to flow out to the cooling medium outlet 21 , thereby preventing the high-temperature cooling medium from repeatedly flowing through the high-temperature area below the chip 11 .

[0058] The flow diagram of the cooling medium in this embodiment is as follows: Figure 14 As shown, the cooling medium flows to the guide baffle 3 through two cooling medium inlets, and the high-temperature area of the module is cooled in a direction through the guiding effect of the guide holes 5 in the guide baffle 3. The cooling medium after heat exchange flows to the cooling medium outlet 21 respectively through the guiding effect of the guide plate 6.

[0059] Example 4, a high-efficiency double-layer heat dissipation structure for a power module, differs from Example 2 in that: Figure 15 As shown, the guide hole 5 is in the shape of a square.

[0060] Example 5, a high-efficiency double-layer heat dissipation structure for a power module, differs from Example 2 in that: Figure 16 As shown, the guide hole 5 is in the shape of an elongated strip.

[0061] In addition to the above embodiments, the shape of the guide hole 5 can also be elliptical, oblong, rectangular, etc.

[0062] Example 6. An efficient double-layer heat dissipation structure for a power module, which is different from that of Example 2 in that, as Figure 17 shown, a number of guiding holes 5 are provided corresponding to each chip 11 area, and a number of guiding holes 5 in each chip 11 area form a porous heat dissipation set, and by adjusting the position, size and shape of the heat dissipation set, the balanced and efficient heat dissipation of the module is realized.

[0063] In addition to the above embodiments, the present invention may have other embodiments. Any technical solutions formed by equivalent replacement or equivalent transformation fall within the protection scope required by the present invention.

Claims

1. An efficient double-layer heat dissipation structure for a power module, comprising a power unit (1) with a plurality of parallel chips (11), characterized in that: A heat dissipation structure is mounted at the bottom of the power unit (1) and is in contact therewith. The heat dissipation structure includes a first heat dissipation layer (2), a guiding partition plate (3), and a second heat dissipation layer (4) formed in sequence from top to bottom, and further includes a first cooling medium inlet (41) communicating with a cavity in the second heat dissipation layer (4) for injecting a cooling medium; a cooling medium outlet (21) communicating with a cavity in the first heat dissipation layer (2) for discharging the heat-exchanged cooling medium; at least one guiding hole (5) is formed in the guiding plate corresponding to the position of the chip (11) for communicating the cavities in the first heat dissipation layer (2) and the second heat dissipation layer (4); a flow guiding plate (6) perpendicular to the flow direction of the cooling medium is provided on at least one side of each guiding hole (5), and a region corresponding to the chip (11) is formed between adjacent flow guiding plates (6); the length of the flow guiding plate (6) is less than the width of the cavity in the first heat dissipation layer (2), and a channel for the cooling medium to flow through is left between the flow guiding plate (6) and the inner side surface of the first heat dissipation layer (2).

2. The high-efficiency double-layer heat dissipation structure of a power module according to claim 1, wherein: A second cooling medium inlet (22) communicating with the cavity is provided on one side of the first heat dissipation layer (2) far from the cooling medium outlet (21).

3. The high-efficiency double-layer heat dissipation structure of a power module according to claim 1, wherein: The shape of the guiding hole (5) is any one of a circle, an ellipse, or a rectangle.

4. The highly efficient double-layer heat dissipation structure of a power module according to claim 1, characterized in that: A plurality of guiding holes (5) are provided in each chip (11) region corresponding to each chip (11), and the plurality of guiding holes (5) in each chip (11) region form a porous heat dissipation set.

5. A power module with a double-layer heat dissipation structure, characterized in that: It includes a power unit (1) and a double-layer heat dissipation structure connected thereto. A plurality of chips (11) arranged in an array are provided on the power unit (1), and the chips (11) are powered by a positive electrode (12), a negative electrode (13), and an output electrode (14) provided on the power unit (1); a plurality of signal electrodes (15) are further provided on the power unit (1), and the signal electrodes (15) are electrically connected to the chips (11); the double-layer heat dissipation structure is the high-efficiency double-layer heat dissipation structure of the power module according to any one of claims 1 to 4.

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