Cooling oil direct current convergent type power module immersion heat dissipation structure

Abstract

The invention discloses a cooling oil direct current convergent type power module immersion heat dissipation structure which comprises a shell which comprises a bottom wall, a top wall, a first side wall, a second side wall, a third side wall, a fourth side wall and a cavity defined by the bottom wall, the top wall, the first side wall, the second side wall, the third side wall and the fourth side wall, an oil inlet hole is formed in the first side wall, and an oil outlet hole is formed in the second side wall; a liquid cooling radiator is arranged at the bottom in the cavity, a substrate is arranged on the liquid cooling radiator, and a power semiconductor chip and a drainage structure are arranged on the substrate; the bottom surface of the power semiconductor chip is connected with the top surface of the substrate, and the top surface and the side surface of the power semiconductor chip are exposed in the cavity; the drainage structures are located on the two sides of the power semiconductor chip and used for converging cooling oil to the side faces and the top face of the power semiconductor chip and conducting heat dissipation on the top face and the side faces of the power semiconductor chip. The heat dissipation of the bottom surface, the top surface and the side surfaces of the power semiconductor chip can be realized, and the heat dissipation efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of power module heat dissipation, and more specifically to a cooling oil direct current convergence type power module immersion heat dissipation structure. Background Art

[0002] With the continuous improvement of the power density of power modules, efficient cooling technology has become the key to their design and development. In order to solve the heat dissipation problem of power modules, domestic and foreign scholars and manufacturers have adopted single-sided and double-sided cooling technologies. Among them, single-sided cooling connects the bottom surface of the power semiconductor chip to an air-cooled or liquid-cooled radiator through a high thermal conductivity medium, so that the heat generated by the chip is transferred from its bottom surface to the radiator for dissipation; when using a double-sided heat dissipation structure, in addition to the bottom surface, the electrode on the top surface of the chip is also connected to the radiator through a high thermal conductivity medium. At this time, the heat generated by the chip can be dissipated from the bottom and top surfaces at the same time.

[0003] However, the single-sided and double-sided heat dissipation structures still have their own shortcomings: (1) For single-sided cooling, its advantage is that the structure is simple, but it can only achieve cooling of the bottom surface of the power semiconductor chip, and the heat dissipation efficiency is low. (2) Double-sided cooling can achieve simultaneous heat dissipation of the bottom and top surfaces of the power semiconductor chip, but on the one hand, it increases the total weight of the heat sink and is not conducive to improving the power density. On the other hand, the electrode area on the top surface of the chip is relatively small, and its heat transfer efficiency is relatively low, which is difficult to meet the actual heat dissipation requirements of high power density modules. Summary of the invention

[0004] The purpose of the present invention is to provide a cooling oil DC convergence power module immersion heat dissipation structure to achieve heat dissipation on the bottom, top and side surfaces of a power semiconductor chip and improve heat dissipation efficiency.

[0005] To achieve the above object, the present invention proposes a cooling oil DC convergence power module immersion heat dissipation structure, comprising:

[0006] A shell, the shell comprising a bottom wall, a top wall, a first side wall, a second side wall, a third side wall and a fourth side wall and a cavity enclosed by the bottom wall, the first side wall and the second side wall are two opposite side walls extending in a width direction of the shell, the third side wall and the fourth side wall are two opposite side walls extending in a length direction of the shell, the first side wall is provided with an oil inlet hole, and the second side wall is provided with an oil outlet hole;

[0007] A liquid cooling radiator is provided at the bottom of the cavity, a substrate is provided on the liquid cooling radiator, and a power semiconductor chip and a drainage structure are provided on the substrate;

[0008] The bottom surface of the liquid-cooled radiator is connected to the bottom wall, and the two sides of the liquid-cooled radiator are respectively in contact with the third side wall and the fourth side wall, and the liquid-cooled radiator has a flow channel arranged along the length direction of the shell, which is used to dissipate heat from the bottom surface of the power semiconductor chip; the two ends of the liquid-cooled radiator are respectively spaced from the first side wall and the second side wall;

[0009] The bottom surface of the power semiconductor chip is connected to the top surface of the substrate, and the top surface and side surfaces of the power semiconductor chip are exposed in the cavity; the drainage structure is located on both sides of the power semiconductor chip, and is used to gather cooling oil to the side surfaces and top surface of the power semiconductor chip to dissipate heat from the top surface and side surfaces of the power semiconductor chip.

[0010] Optionally, the drainage structure includes a first busbar and a second busbar disposed on the substrate in the longitudinal direction, the first busbar is located on a side close to the third side wall, the second busbar is located on a side close to the fourth side wall, and the power semiconductor chip is located between the first busbar and the second busbar;

[0011] The projections of the first busbar and the second busbar on the substrate are two arcs extending along the length direction of the shell and axially symmetrically distributed, and along the direction from the first side wall to the second side wall, the distance between the first busbar and the second busbar gradually decreases from one end of the power semiconductor chip to the other end of the power semiconductor chip; a plurality of first guide plates are provided on a surface of the first busbar facing the power semiconductor chip, and the plurality of first guide plates are spaced apart along the length direction of the shell, and the first guide plate extends longitudinally from the top of the first busbar to the top of the first busbar, one end of the first guide plate is connected to the first busbar, and the other end of the first guide plate is inclined toward the downstream direction of the cooling oil;

[0012] A plurality of second guide plates are provided on a surface of one side of the second busbar facing the power semiconductor chip, and the plurality of second guide plates are spaced apart along the length direction of the shell. The second guide plates extend longitudinally from the top of the first busbar to the top of the second busbar, and one end of the second guide plate is connected to the second busbar, and the other end of the second guide plate is inclined toward the downstream direction of the cooling oil flow.

[0013] Optionally, the angle between the first guide plate and the first busbar is in a range of 30° to 60°, and the angle between the second guide plate and the second busbar is equal to the angle between the first guide plate and the first busbar.

[0014] Optionally, a plurality of the first drain plates and a plurality of the second drain plates are arranged opposite to each other one by one, and the distance between the first drain plates and the power semiconductor chip is equal to the distance between the second drain plates and the power semiconductor chip.

[0015] Optionally, the height of the first busbar and the second busbar is greater than the thickness of the power semiconductor chip, and the length of the first busbar and the second busbar is greater than the length of the power semiconductor chip.

[0016] Optionally, there is a gap between the top of the first busbar and the second busbar and the top wall, or the first busbar and the second busbar are connected to the top wall.

[0017] Optionally, the substrate is a DBC substrate, and the DBC substrate includes a lower copper layer, a ceramic layer and an upper copper layer stacked from bottom to top;

[0018] The lower copper layer of the DBC substrate is connected to the top surface of the liquid cooling radiator through a connecting layer;

[0019] The bottom surface of the power semiconductor chip is welded to the upper copper layer of the DBC substrate through a welding layer;

[0020] The bottoms of the first busbar and the second busbar are welded to the upper copper layer of the DBC substrate.

[0021] Optionally, the connection layer is silicone grease, adhesive or welding layer.

[0022] Optionally, the oil inlet hole is arranged at the center of the first side wall, and the oil outlet hole is arranged at the center of the second side wall.

[0023] Beneficial effects of the present invention are that the cooling oil DC convergence type power module immersion heat dissipation structure is provided in the shell cavity from bottom to top in sequence with a liquid cooling radiator, a substrate and a power semiconductor chip, and the side walls at both ends of the shell are provided with oil inlet holes and oil outlet holes. After the cooling oil enters the shell, a part of the cooling oil flows into the radiator at the bottom to dissipate the bottom surface of the power semiconductor chip, and the other part is gathered around the power semiconductor chip through the drainage structure to dissipate the top surface and side surface of the power semiconductor chip. The heat dissipation structure can simultaneously achieve heat dissipation of the bottom surface, top surface and side surface of the power semiconductor chip. And the top surface area utilization rate is high, which can effectively improve the heat dissipation efficiency; at the same time, the present invention also adds additional drainage structures on both sides of the power semiconductor chip, and drains the cooling oil to the top and side surfaces of the power semiconductor chip through the drainage structure, thereby enhancing the heat dissipation effect on the semiconductor chip; secondly, the present invention connects the cooling flow path in the liquid-cooled radiator in parallel with the cooling oil path around the chip, and the total amount of cooling oil flowing in is divided, with one part participating in the heat dissipation of the radiator (bottom surface of the power semiconductor chip), and the other part flowing through the top surface / side surface of the chip to achieve heat dissipation, thereby ensuring high heat dissipation efficiency while maintaining an overall small flow resistance.

[0024] Furthermore, the drainage structure of the present invention includes a pair of busbars, each busbar has a plurality of drainage plates on the side facing the power semiconductor chip, the two busbars are projected on the substrate to form two axially symmetrical arcs, and the distance between the two busbars gradually narrows from wide to narrow along the flow direction of the cooling oil. This structural design can collect the cooling oil to the periphery of the power semiconductor chip and increase the flow rate of the cooling oil around the chip. At the same time, the plurality of drainage plates are inclined at a certain angle downstream in the flow direction of the cooling oil. This structure can make the cooling oil flowing between the two busbars further collect to the area where the chip is located, and at the same time further enhance the cooling oil flow rate on the sides and top of the chip, thereby enhancing the heat dissipation effect on the top and sides of the chip. In addition, the inclined drainage plates can also prevent the cooling oil from flowing in the opposite direction, thereby enhancing the circulation effect of the cooling oil in the shell.

[0025] The system of the present invention has other characteristics and advantages, which will be apparent from the drawings incorporated herein and the following detailed description, or will be described in detail in the drawings incorporated herein and the following detailed description, which together serve to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, in which like reference numerals generally represent like components.

[0027] Figure 1 and Figure 2They are respectively a longitudinal cross-sectional view of a cooling oil DC convergence power module immersion heat dissipation structure and a top view of the chip top surface according to Embodiment 1 of the present invention. DETAILED DESCRIPTION

[0028] The present invention will be described in more detail below with reference to the accompanying drawings. Although preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0029] Example 1

[0030] like Figure 1 As shown, this embodiment provides a cooling oil DC convergence power module immersion heat dissipation structure, including:

[0031] A shell 1, the shell 1 comprises a bottom wall 101, a top wall 102, a first side wall 103, a second side wall 104, a third side wall 105 and a fourth side wall 106 and a cavity enclosed by them, the first side wall 103 and the second side wall 104 are two opposite side walls extending along the width direction of the shell 1, the third side wall 105 and the fourth side wall 106 are two opposite side walls extending along the length direction of the shell 1, the first side wall is provided with an oil inlet hole 10, and the second side wall is provided with an oil outlet hole 11; a liquid-cooled radiator 2 is provided at the bottom of the cavity, a substrate is provided on the liquid-cooled radiator 2, and a power semiconductor chip 9 and a drainage structure 12 are provided on the substrate;

[0032] The bottom surface of the liquid-cooled radiator 2 is connected to the bottom wall 101, and the two sides of the liquid-cooled radiator 2 are respectively in contact with the third side wall 105 and the fourth side wall 106. The liquid-cooled radiator 2 has a flow channel arranged along the length direction of the housing 1, which is used to dissipate heat from the bottom surface of the power semiconductor chip 9; the two ends of the liquid-cooled radiator 2 are spaced from the first side wall 103 and the second side wall 104 respectively;

[0033] The bottom surface of the power semiconductor chip 9 is connected to the top surface of the substrate, and the top surface and side surfaces of the power semiconductor chip 9 are exposed in the cavity; the drainage structure 12 is located on both sides of the power semiconductor chip 9, and is used to gather cooling oil to the side surfaces and top surfaces of the power semiconductor chip 9 to dissipate heat from the top surface and side surfaces of the power semiconductor chip 9.

[0034] In this embodiment, the substrate is a DBC substrate (Direct Copper Bond, directly copper-bonded ceramic substrate), and the DBC substrate includes a lower copper layer 4, a ceramic layer 5, and an upper copper layer 6 stacked from bottom to top; the lower copper layer 4 of the DBC substrate is connected to the top surface of the liquid cooling radiator 2 through a connecting layer 3; the bottom surface of the power semiconductor chip 9 is welded to the upper copper layer 6 of the DBC substrate through a welding layer 8; the bottoms of the first busbar 12a and the second busbar 12b are welded to the upper copper layer 6 of the DBC substrate. Wherein, the connecting layer 3 is silicone grease, adhesive or welding layer 8.

[0035] like Figure 2 As shown, in this embodiment, the drainage structure 12 includes a first busbar 12a and a second busbar 12b which are arranged on the substrate in the longitudinal direction, the first busbar 12a is located on a side close to the third side wall 105, the second busbar 12b is located on a side close to the fourth side wall 106, and the power semiconductor chip 9 is located between the first busbar 12a and the second busbar 12b;

[0036] The projections of the first busbar 12a and the second busbar 12b on the substrate are two arcs extending along the length direction of the housing 1 and axially symmetrically distributed, and along the flow direction of the cooling oil 7 (i.e., from the first side wall 103 to the second side wall 104), the distance between the first busbar 12a and the second busbar 12b gradually decreases from one end of the power semiconductor chip 9 to the other end of the power semiconductor chip 9;

[0037] A plurality of first guide plates 12c are provided on a surface of one side of the first busbar 12a facing the power semiconductor chip 9. The plurality of first guide plates 12c are spaced apart along the length direction of the housing 1. The first guide plates 12c extend longitudinally from the top of the first busbar 12a to the top of the first busbar 12a. One end of the first guide plate 12c is connected to the first busbar 12a, and the other end of the first guide plate 12c is inclined toward the downstream direction of the cooling oil 7.

[0038] A plurality of second guide plates 12d are provided on one side surface of the second busbar 12b facing the power semiconductor chip 9. The plurality of second guide plates 12d are spaced apart along the length direction of the shell 1. The second guide plates 12d extend longitudinally from the top of the first busbar to the top of the second busbar 12b. One end of the second guide plate 12d is connected to the second busbar 12b, and the other end of the second guide plate 12d is inclined toward the downstream direction of the flow of the cooling oil 7.

[0039] Preferably, the angle between the first guide plate 12c and the first busbar 12a (angle α in the figure) ranges from 30° to 60°, and the angle between the second guide plate 12d and the second busbar 12b is equal to the angle between the first guide plate 12c and the first busbar 12a.

[0040] In this embodiment, a plurality of first drain plates 12c and a plurality of second drain plates 12d are arranged opposite to each other, and the distance between the first drain plates 12c and the power semiconductor chip 9 is equal to the distance between the second drain plates 12d and the power semiconductor chip 9.

[0041] Further, in this embodiment, the height of the first busbar 12a and the second busbar 12b is greater than the thickness of the power semiconductor chip 9, and the length of the first busbar 12a and the second busbar 12b is greater than the length of the power semiconductor chip 9. There is a gap between the top of the first busbar 12a and the second busbar 12b and the top wall 102.

[0042] Specifically, the drainage structure 12 of this embodiment can collect part of the cooling oil 7 entering the cavity to the surrounding of the power semiconductor chip 9, and increase the flow rate of the cooling oil 7 around the chip; at the same time, the multiple drainage plates are inclined at a certain angle downstream of the flow direction of the cooling oil 7, and the multiple drainage plates can make the cooling oil 7 flowing between the two manifolds further collect to the area where the chip is located, further increase the flow rate of the cooling oil 7 on the sides and top of the chip, thereby enhancing the heat dissipation effect on the top and sides of the chip. In addition, the drainage plates inclined toward the downstream direction of the cooling oil 7 can also prevent the cooling oil from flowing in the reverse direction, and enhance the circulation flow effect of the cooling oil in the housing 1. In addition, since the multiple first drainage plates 12c and the multiple second drainage plates 12d are opposite to each other and the distances between the first drainage plates 12c, the second drainage plates 12d and the power semiconductor chip 9 are equal, the flow rate and flow rate of the cooling oil 7 flowing through both sides of the power semiconductor chip 9 can be made the same, avoiding the generation of eddy currents or turbulence, and improving the circulation effect and heat dissipation effect of the cooling oil 7. Secondly, the height of the first busbar 12a and the second busbar 12b is greater than the thickness of the power semiconductor chip 9, and the length of the first busbar 12a and the second busbar 12b is greater than the length of the power semiconductor chip 9, which can ensure that the top surface and side surfaces of the power semiconductor chip 9 are completely located in the drainage structure, ensuring that sufficient cooling oil flows through the top surface and side surfaces of the chip.

[0043] The liquid-cooled radiator 2 of the cooling oil DC convergence power module immersion heat dissipation structure of the present embodiment is installed on the inner bottom surface of the shell 1, and the lower copper layer 4 of the DBC substrate is connected to the liquid-cooled radiator 2 through the connecting layer 3 (which can be silicone grease, adhesive or welding layer 8); the power semiconductor chip 9 is welded to the copper layer 6 on the DBC substrate through the welding layer 8; due to the presence of the DBC substrate ceramic layer 5, the power semiconductor chip 9 is electrically insulated from the liquid-cooled radiator 2; an oil inlet hole 10 is set in the center of the first side wall 103 at one end of the shell 1, and an oil outlet hole 11 is set in the center of the second side wall 104 at the other end of the shell 1.

[0044] In this embodiment, the circulation process of the cooling oil 7 in the housing 1 is as follows: the cooling oil 7 flows into the housing from the oil inlet 10, and then the cooling oil 7 is divided; one part flows into the liquid cooling radiator 2 to achieve efficient heat dissipation of the bottom surface of the power semiconductor chip 9; one part is gathered around the power semiconductor chip 9 through the drainage structure 12 outside the liquid cooling radiator 2 to achieve efficient heat dissipation of the top and side surfaces of the power semiconductor chip 9; the two parts of cooling oil are aggregated near the oil outlet 11 and flow out of the housing 1 from the oil outlet 11. Due to the cooling oil DC convergence power module immersion heat dissipation structure, the bottom, side and top surfaces of the power semiconductor chip can be cooled simultaneously, with high cooling efficiency, and the two parts of the cooling oil circuit are connected in parallel, so the overall flow resistance is low.

[0045] The heat dissipation structure of the present embodiment can simultaneously realize the heat dissipation of the bottom, top and side surfaces of the power semiconductor chip 9, and the top surface area utilization rate is high, which can effectively improve the heat dissipation efficiency; at the same time, through the drainage structure 12 added on both sides of the power semiconductor chip 9, the cooling oil 7 is drained to the top and side surfaces of the power semiconductor chip 9, effectively enhancing the heat dissipation effect of the power semiconductor chip 9; secondly, the heat dissipation structure connects the cooling flow path in the liquid-cooled radiator 2 in parallel with the cooling oil 7 paths around the chip, and the total amount of cooling oil flowing in is divided, a part of which participates in the heat dissipation of the liquid-cooled radiator 2 (the bottom surface of the power semiconductor chip 9), and a part of which flows through the top and side surfaces of the power semiconductor chip 9 to achieve heat dissipation, thereby ensuring high heat dissipation efficiency while maintaining an overall small flow resistance.

[0046] In other embodiments, the first busbar 12a and the second busbar 12b may also be connected to the top wall 102, and one end of the first busbar 12a close to the second side wall 103 is in contact with the third side wall 105, and one end of the second busbar 12b close to the second side wall 104 is in contact with the fourth side wall 106. In this case, the cooling oil 7 in the upper channel can be completely converged to the top and side surfaces of the power semiconductor chip 9 through the drainage structure 12, thereby further enhancing the cooling effect.

[0047] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A cooling oil DC convergence power module immersion heat dissipation structure, characterized in that: include: A shell, the shell comprising a bottom wall, a top wall, a first side wall, a second side wall, a third side wall and a fourth side wall and a cavity enclosed by the bottom wall, the first side wall and the second side wall are two opposite side walls extending in a width direction of the shell, the third side wall and the fourth side wall are two opposite side walls extending in a length direction of the shell, the first side wall is provided with an oil inlet hole, and the second side wall is provided with an oil outlet hole; A liquid cooling radiator is provided at the bottom of the cavity, a substrate is provided on the liquid cooling radiator, and a power semiconductor chip and a drainage structure are provided on the substrate; The bottom surface of the liquid-cooled radiator is connected to the bottom wall, and the two sides of the liquid-cooled radiator are respectively in contact with the third side wall and the fourth side wall, and the liquid-cooled radiator has a flow channel arranged along the length direction of the shell, which is used to dissipate heat from the bottom surface of the power semiconductor chip; the two ends of the liquid-cooled radiator are respectively spaced from the first side wall and the second side wall; The bottom surface of the power semiconductor chip is connected to the top surface of the substrate, and the top surface and side surfaces of the power semiconductor chip are exposed in the cavity; the drainage structure is located on both sides of the power semiconductor chip, and is used to gather cooling oil to the side surfaces and top surface of the power semiconductor chip to dissipate heat from the top surface and side surfaces of the power semiconductor chip.

2. The cooling oil DC convergence power module immersion heat dissipation structure according to claim 1 is characterized in that: The drainage structure comprises a first busbar and a second busbar which are arranged on the substrate in the longitudinal direction, the first busbar is located on a side close to the third side wall, the second busbar is located on a side close to the fourth side wall, and the power semiconductor chip is located between the first busbar and the second busbar; The projections of the first busbar and the second busbar on the substrate are two arcs extending along the length direction of the shell and axially symmetrically distributed, and along the direction from the first side wall to the second side wall, the distance between the first busbar and the second busbar gradually decreases from one end of the power semiconductor chip to the other end of the power semiconductor chip; a plurality of first guide plates are provided on a surface of the first busbar facing the power semiconductor chip, and the plurality of first guide plates are spaced apart along the length direction of the shell, and the first guide plate extends longitudinally from the top of the first busbar to the top of the first busbar, one end of the first guide plate is connected to the first busbar, and the other end of the first guide plate is inclined toward the downstream direction of the cooling oil; A plurality of second guide plates are provided on a surface of one side of the second busbar facing the power semiconductor chip, and the plurality of second guide plates are spaced apart along the length direction of the shell. The second guide plates extend longitudinally from the top of the first busbar to the top of the second busbar, and one end of the second guide plate is connected to the second busbar, and the other end of the second guide plate is inclined toward the downstream direction of the cooling oil flow.

3. The cooling oil DC convergence power module immersion heat dissipation structure according to claim 2 is characterized in that: The included angle between the first guide plate and the first busbar is in a range of 30° to 60°, and the included angle between the second guide plate and the second busbar is equal to the included angle between the first guide plate and the first busbar.

4. The cooling oil DC convergence power module immersion heat dissipation structure according to claim 3 is characterized in that: The plurality of first drain plates and the plurality of second drain plates are arranged opposite to each other one by one, and the distance between the first drain plates and the power semiconductor chip is equal to the distance between the second drain plates and the power semiconductor chip.

5. The cooling oil DC convergence power module immersion heat dissipation structure according to claim 4 is characterized in that: The heights of the first busbar and the second busbar are greater than the thickness of the power semiconductor chip, and the lengths of the first busbar and the second busbar are greater than the length of the power semiconductor chip.

6. The cooling oil DC convergence power module immersion heat dissipation structure according to claim 5, characterized in that: There is a gap between the top of the first busbar and the second busbar and the top wall, or the first busbar and the second busbar are connected to the top wall.

7. The cooling oil DC convergence power module immersion heat dissipation structure according to claim 1, characterized in that: The substrate is a DBC substrate, and the DBC substrate includes a lower copper layer, a ceramic layer and an upper copper layer stacked from bottom to top; The lower copper layer of the DBC substrate is connected to the top surface of the liquid cooling radiator through a connecting layer; The bottom surface of the power semiconductor chip is welded to the upper copper layer of the DBC substrate through a welding layer; The bottoms of the first busbar and the second busbar are welded to the upper copper layer of the DBC substrate.

8. The cooling oil DC convergence power module immersion heat dissipation structure according to claim 7, characterized in that: The connecting layer is silicone grease, adhesive or welding layer.

9. The cooling oil DC convergence power module immersion heat dissipation structure according to claim 1, characterized in that: The oil inlet hole is arranged at the center of the first side wall, and the oil outlet hole is arranged at the center of the second side wall.

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