Immersed heat dissipation structure

Abstract

According to the immersed heat dissipation structure, the protective cover is additionally arranged on the outer side of the power module, and the opening structure is arranged on the side face of the protective cover, so that metal particles in cooling liquid are prevented from entering the power module, and the safety and reliability of the module are improved. And meanwhile, the cooling liquid can flow or gasify in the module through the opening structure of the protective cover to take away heat transferred into the module through the carrier plate from the interior or surface parts of the module, so that the heat dissipation capability of the module is improved. And on the other hand, various protective cover implementation modes are provided, and the protective cover is suitable for different application scenes.

Description

Technical Field

[0001] This invention belongs to the field of high-frequency power supply technology, and particularly relates to an immersion heat dissipation structure. Background Technology

[0002] With the ever-increasing demand for artificial intelligence and data processing, the computing power of various circuit boards is constantly improving, which in turn leads to a year-on-year increase in the power consumption of computing chips. At the same time, due to the extremely high size constraints of these computing units, increasingly higher requirements are being placed on the footprint and heat dissipation of energy processing units.

[0003] To reduce the footprint of power processing units, 3D stacked power modules are becoming a trend. Immersion cooling can be used to improve the heat dissipation performance of power modules; however, immersion cooling is prone to trapping conductive particles in the coolant, such as solder balls from the surface of PCBA components. These conductive particles can flow in the coolant and may cause bridging between adjacent electrodes, leading to functional failures or even catastrophic failures such as burn-out or failure of the power module and computing chip.

[0004] To address these issues, a conformal coating is typically applied to the surface of the printed circuit board assembly (PCBA) to provide surface insulation. However, when using 3D stacked power modules, it is difficult to coat the components between the layers with insulating material. Therefore, effectively protecting these areas is an urgent problem to be solved. Summary of the Invention

[0005] In view of this, one of the objectives of the present invention is to provide an immersion heat dissipation structure, including a power module, a motherboard, and a protective cover; the power module includes a carrier plate, the carrier plate including opposing upper and lower surfaces, and a side surface; the side surface of the carrier plate is disposed between the upper and lower surfaces of the carrier plate; at least one element is disposed on the upper and lower surfaces of the carrier plate.

[0006] The motherboard includes an upper surface and a lower surface opposite each other; the upper surface of the motherboard is disposed adjacent to the lower surface of the carrier board;

[0007] The protective cover includes a lower edge surface and a side surface, the side surface of the protective cover extending from the upper surface of the motherboard to at least the carrier board of the power module; the projected outline of the protective cover on a horizontal plane completely includes the projected outline of the power module on the same horizontal plane; the side surface of the protective cover has an opening structure, the size of at least one dimension of the opening structure being less than 0.15 mm.

[0008] Preferably, the protective cover includes opening structures on at least two sides, and the area of ​​the opening structure on one of the sides is greater than 10%.

[0009] Preferably, the opening structure is formed directly by injection molding or by post-processing methods such as mechanical or laser processing.

[0010] Preferably, the protective cover further includes an upper edge surface, the lower edge surface and the upper surface of the motherboard are fixed by an adhesive material, and the upper edge surface and the carrier plate are fixed by an adhesive material.

[0011] Preferably, the protective cover includes an upper edge surface that is higher than the upper surface of the carrier plate, and the upper surface of the main board and the inner surface of the protective cover are fixed by an adhesive material.

[0012] Preferably, the gap between the protective cover and the motherboard is filled with an adhesive material, and the gap between the protective cover and the carrier board is filled with an adhesive material; the adhesive material is insoluble in immersion coolant; the adhesive material includes silicone, acrylic resin, polyimide, and polyurethane.

[0013] Preferably, the protective cover includes a frame made of insulating material; or the interior of the frame is made of metal and the surface of the frame is made of insulating material.

[0014] Preferably, the protective cover further includes a skin structure, which is assembled with the frame by any one of bonding, skin tension, or interference fit; the thickness of the skin is less than 500 μm; the opening structure of the skin is formed by laser cutting small holes or photolithography with photosensitive material.

[0015] Preferably, the protective cover further includes a mesh structure, the mesh structure comprising at least one layer of woven mesh, the mesh having an aperture of less than 0.15 mm in at least one dimension; the mesh material is glass fiber or organic fiber, etc.

[0016] Preferably, the height of the protective cover is higher than the height of the power module, and the protective cover also includes an upper cover plate; the protective cover and the power module are assembled on the motherboard, and the protective cover completely encloses the power module.

[0017] Preferably, the power module further includes an adapter plate and a connector. The adapter plate includes an upper surface and a lower surface opposite to each other. The connector is disposed between the adapter plate and the main board. The lower surface of the adapter plate is adjacent to and fixed to the upper surface of the main board.

[0018] Preferably, the protective cover is a mesh structure, and the inner side of the mesh structure is fixedly connected to the side of the carrier plate and the side of the adapter plate.

[0019] Preferably, after the protective cover is fixedly connected to the side of the carrier plate and the side of the adapter plate, the power module is then assembled with the motherboard.

[0020] Preferably, the device further includes a metal plate, and the protective cover also includes an upper edge surface. The height of the protective cover is greater than the height of the power module. The metal plate is disposed on the upper edge surface. The metal plate includes an upper surface and a lower surface opposite to each other. The lower surface of the metal plate is thermally connected to the heating element in the power module through a thermally conductive interface material, wherein the thermally conductive interface material is a curable thermally conductive material.

[0021] Preferably, the lower surface of the metal plate further includes a step, which is thermally connected to the heating element in the power module through a thermally conductive interface material; the thermally conductive interface material is a curable thermally conductive material.

[0022] Preferably, the metal plate further includes an exhaust hole with a diameter of less than 0.15 mm; the exhaust hole is positioned to avoid contact with the thermal connection area.

[0023] The beneficial effects of this invention are:

[0024] (1) The present invention proposes an immersion heat dissipation structure, which is to prevent metal particles in the coolant from entering the power module by adding a protective cover to the outside of the power module and setting an opening structure on the side of the protective cover, thereby improving the safety and reliability of the module.

[0025] (2) The coolant can flow or vaporize inside the module through the opening structure of the protective cover to carry away the heat transferred to the inside of the module by the internal or surface parts through the carrier plate, thereby improving the module's heat dissipation capacity.

[0026] (3) On the other hand, the present invention provides various implementations of protective covers, which are suitable for different application scenarios. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figures 1A to 1D This is a schematic diagram of an immersion heat dissipation structure.

[0029] Figures 2A to 2C This is a schematic diagram of a stacked power module.

[0030] Figures 3A to 3DThis is a schematic diagram showing the fixing of the protective cover to the motherboard and power module;

[0031] Figure 4A and Figure 4B This is a schematic diagram of another type of protective shield;

[0032] Figure 5A and Figure 5B This is a schematic diagram of another type of protective shield;

[0033] Figure 6A and Figure 6B This is a schematic diagram of another type of immersion heat dissipation structure.

[0034] Figure 7 This is a schematic diagram of another type of immersion heat dissipation structure. Detailed Implementation

[0035] One of the core features of this invention is providing an immersion-type heat dissipation structure. By adding a protective cover to the outside of the power module and providing an opening structure on the side of the protective cover, metal particles in the coolant are prevented from entering the power module, thereby improving the module's safety and reliability. Simultaneously, the coolant can flow or vaporize inside the module through the opening structure of the protective cover, carrying away heat transferred from internal or surface components to the interior via the carrier plate, thus improving the module's heat dissipation capacity.

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] The immersion heat dissipation structure provided by this invention is as follows: Figure 1A and Figure 1B As shown, Figure 1A This is a structural diagram. Figure 1B This is a breakdown diagram. Also refer to... Figure 1A and Figure 1BThe power module 10 is mounted on the upper surface 301 of the motherboard 30, and the protective cover 20 is disposed around the power module 10. The power module 10 includes a carrier board 11, which has opposing upper surfaces 111 and lower surfaces 112. Multiple components are respectively disposed on the upper surface 111 and lower surface 112; the lower surface 112 of the carrier board 11 is adjacent to the upper surface 301 of the motherboard 30. The power module also includes four sides disposed between the upper surface 111 and the lower surface 112. The protective cover 20 includes opposing first side surfaces 211 and 213, opposing second side surfaces 212 and 214, an upper edge surface 201, and a lower edge surface 202. Multiple opening structures 210 are disposed on the first side surface 211 to the fourth side surface 214. When the protective cover 20 is assembled with the motherboard 30 and the power module 10, the lower edge surface 202 of the protective cover 20 is fitted to the upper surface 301 of the motherboard 30. The protective cover 20 extends from the upper surface 301 of the motherboard to the carrier plate 11 of the power module in the height direction. The projected outline of the protective cover 20 on a horizontal plane completely encloses the projected outline of the power module 10 in the same horizontal direction. The protective cover 20 can be made of a material of uniform thickness. The protective cover 20 can also have non-uniform thickness characteristics, such as being thinner where an opening structure is required to facilitate the construction of the opening structure, and thicker where structural support is required to provide sufficient strength. In another embodiment, such as... Figure 1C As shown, the opening structure 210 can be provided only on the opposite first side 211 and third side 213, or on the opposite second side 212 and fourth side 214. In two-phase liquid cooling applications, the opening structure 210 is provided on at least two sides to ensure that the two-phase liquid has a good vaporization discharge channel and a liquid replenishment channel.

[0038] like Figure 1D As shown, the opening structure 210 of the protective cover 20 can be in the shape of a round hole, triangular hole, square hole, diamond hole, or hexagonal hole; the opening structure 210 has a dimension of less than 0.15 mm in at least one dimension, that is, there is at least one straight line passing through the center of the opening structure, and the length of the line within the opening structure is less than 0.15 mm. When the power module with the protective cover operates in an immersion liquid cooling environment, the risk of metal particles in the coolant entering the module and causing a short circuit is greatly reduced, improving the safety and reliability of the power module; and because of the existence of the opening structure, the coolant can flow or vaporize inside the module through the opening structure of the protective cover to carry away the heat transferred from the internal or surface parts of the module to the inside through the carrier plate, improving the module's heat dissipation capacity; on the other hand, compared with a completely sealed protective cover, the opening structure provides a pressure relief channel, avoiding the risk of the protective cover falling off during application.

[0039] On the other hand, the opening structure disclosed in this invention occupies more than 10% of the area of ​​one side, thereby ensuring sufficient liquid / vaporization permeability. The opening structure 210 can be directly formed by injection molding or realized by post-processing methods such as mechanical or laser processing.

[0040] This immersion heat dissipation structure is suitable for Figures 2A to 2C The stacked power module shown. (As shown) Figure 2A As shown, the power module includes a carrier board 11, which has an upper surface 111 and a lower surface 112. Multiple components 113 are disposed on the upper surface 111, and components 115 and connectors 114 are disposed on the lower surface 112. The power module is electrically and fixedly connected to the motherboard via connectors 114. Figure 2B As shown, the power module includes a carrier board 11 and an adapter board 12. The carrier board 11 includes an upper surface 111 and a lower surface 112, and the adapter board 12 includes an upper surface 121 and a lower surface 122, with the upper surface 121 of the adapter board adjacent to the lower surface 112 of the carrier board. Multiple components 113 are disposed on the upper surface 111, and connectors 114 and inductor assemblies 116 are disposed between the carrier board 11 and the adapter board 121. The power module is fixed and electrically connected to the main board 30 via the lower surface 212 of the adapter board. Figure 2C The power module shown includes a carrier board 11 and an adapter board 12. The carrier board 11 includes an upper surface 111 and a lower surface 112 opposite to each other, and the adapter board 12 includes an upper surface 121 and a lower surface 122 opposite to each other. The upper surface 121 of the adapter board is disposed adjacent to the lower surface 112 of the carrier board. A plurality of components 113 are disposed on the upper surface 111. A magnetic core assembly 116 is fastened to the carrier board 11. A connector 114 is disposed between the carrier board 11 and the adapter board 121. The power module is fixed and electrically connected to the main board 30 through the lower surface 212 of the adapter board.

[0041] This invention also discloses the fixing method of the protective cover 20, the power module 10, and the motherboard 30, as detailed below. Figures 3A to 3D As shown. Figure 3A As shown, adhesive material 40 is disposed between the lower edge surface 202 of the protective cover and the upper surface 301 of the motherboard, fixing the protective cover to the motherboard and filling the gap between the protective cover and the motherboard. Adhesive material 40 can also be disposed between the upper edge surface 201 of the protective cover and the upper surface 111 of the carrier board for fixing the protective cover and the power module. More details are as follows... Figure 3B As shown, the upper edge surface 201 of the protective cover and the upper surface 111 of the carrier plate are approximately on the same plane. Adhesive material 40 is applied to the edge surface 201 and the upper surface 111, thereby fixing the protective cover 20 and the carrier plate 11 and filling the gap between them. Figure 3CAs shown, the upper edge surface 201 of the protective cover is higher than the upper surface 111 of the carrier plate. Adhesive material 40 is disposed on the upper surface 111 and the inner surface of the protective cover, thereby fixing the protective cover 20 and the carrier plate 11 and filling the gap between them. Optionally, insulating adhesive is injected into the cavity formed by the upper edge surface 201 of the protective cover being higher than the upper surface 111 of the carrier plate to protect the components mounted on the upper surface 111 of the carrier plate. Figure 3D As shown, the upper surface 111 of the carrier plate is higher than the upper edge surface 201 of the protective cover. Adhesive material 40 is placed between the upper edge surface 201 and the side surface of the carrier plate to fix the protective cover 20 and the carrier plate 11, and to fill the gap between them. The sidewall of the carrier plate 11 and the inner sidewall of the protective cover 20 are fitted together, with a gap of less than 0.15 mm being optimal. The adhesive material 40 is a material insoluble in immersion coolant, such as epoxy, silicone, acrylic resin, polyimide, polyurethane, etc. Alternatively, the bottom of the protective cover 20 and the main board 30 can be mechanically locked (a horizontal extension structure can be provided at the bottom of the protective cover for locking, not shown), achieving the same fixing effect and ensuring a gap of less than 0.15 mm between the protective cover and the main board.

[0042] The structure of the protective shield disclosed in this invention is as follows: Figure 4A and Figure 4B As shown, the protective cover 20 includes a frame 221 and a skin 222. The skin 222 is assembled to the frame 221 by bonding, skin tension, or interference fit. The frame 221 can be made of insulating material; it can also be a composite structure with an internal metal material and a surface insulating material, where the metal provides strength support for the frame and the surface insulating material provides insulation. The skin 222 can be extremely thin, for example, less than 500 μm thick, with less than 200 μm being optimal. The opening structure on the skin 222 can be formed by laser cutting small holes or by photolithography using photosensitive materials. The skin structure can further increase the gaseous / liquid flow of coolant, and the thinness of the skin reduces the processing difficulty of the opening structure.

[0043] Alternatively, a mesh structure can be used to replace the skin and assembled with the frame to form a protective cover. The mesh structure can be a woven screen, and the weaving material can be glass fiber, organic fiber, etc.; the pore size of the mesh structure is less than 0.15mm in at least one dimension; to ensure the stability of the mesh size, organic materials can be used for local fixation, such as impregnating the woven screen with a photosensitive adhesive material and then defining the adhesive pattern through photochemical methods. Furthermore, the mesh structure can be a single layer or multiple layers to prevent single-layer screens from breaking under the impact of coolant flow and internal exhaust of the module. Multi-layer structures can also increase the reliability of the mesh structure; furthermore, the opening structure of each layer of the mesh structure in a multi-layer structure can be inconsistent to better prevent foreign objects from entering the power module. Furthermore, the skin can be a single layer or multiple layers, and can be set adjacent to each other or spaced apart (the corresponding frame structure can be adapted to support multiple layers of skin) to achieve a better effect in preventing conductive particles from entering.

[0044] The protective cover 20 may also include a top cover 215, which can be referred to at the same time. Figure 5A and Figure 5B It should be noted that the top cover 215 is not specifically a separate component; it can be part of a one-piece molded protective cover or part of an integral skin, etc. When the protective cover 20 is assembled onto the motherboard 30, it can completely enclose the power module. This protective cover only needs to be assembled with the motherboard, simplifying the process and reducing the stress on the bonding points caused by the tolerances and thermal expansion and contraction of the power module when the upper and lower parts of the protective cover are connected simultaneously, thus increasing the reliability of the connection.

[0045] In another embodiment, such as Figure 6A As shown, the protective cover 20 can also use only one layer of mesh structure, which can be directly fixed to the side of the carrier plate 11 and the adapter plate 21. That is, the carrier plate 11 and the adapter plate 21 are used as a frame to fix the mesh structure, which can also achieve the same protective effect. Moreover, this structure does not require additional assembly steps, the process is simple, and there is no need for an external frame, which saves space and increases power density.

[0046] In another embodiment, such as Figure 6B As shown, the protective cover 20 can be first assembled with the power module, that is, bonded and fixed to the sides of the carrier board 11 and the adapter board 21, and then assembled and fixed to the motherboard together with the module. This structure reduces the assembly process for the client and makes it more convenient for the customer to use.

[0047] This invention also discloses an immersion heat dissipation structure, such as Figure 7As shown. The heat dissipation structure also includes a metal plate 50, which is positioned above the protective cover 20. The power module 10 is first assembled onto the upper surface 301 of the motherboard, and then the protective cover 20 is fixedly connected to the motherboard 30. The height of the protective cover 20 is higher than the height of the power module 10. The metal plate 50 is positioned on the upper edge 201 of the protective cover. The metal plate 50 can be thermally connected to the heat-generating device through a thermally conductive interface material 50; alternatively, a step can be provided on the lower surface of the metal plate, allowing it to be thermally connected to heat-generating devices at different heights through the thermally conductive interface material 50, thereby reducing the equivalent thermal resistance along the heat propagation path and achieving better heat dissipation. The metal plate 50 also includes an exhaust hole 51, which can be one or multiple. The diameter of the exhaust hole is less than 0.15 mm, and the location of the exhaust hole should simply avoid the thermal contact area between the metal plate and the heat-generating device. A curable thermally conductive material is preferred for the thermally conductive interface material 50.

[0048] The power module described in the above embodiments can also be part of an electronic device, as long as it meets the technical features and benefits disclosed in this invention.

[0049] The terms "equal," "identical," "equal to," or "coplanar" disclosed in this invention must take into account the parameter distribution of the engineering process, with an error distribution within ±30%. "Parallel" is defined as the angle between two line segments or lines being less than or equal to 45 degrees. "Perpendicular" is defined as the angle between two line segments or lines being within the range of [60, 120] degrees. The definition of "phase misalignment" also needs to consider the parameter distribution of the engineering process, with an error distribution of the phase misalignment degree within ±30%.

[0050] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0051] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An immersion heat dissipation structure, characterized by, The device includes a power module, a motherboard, and a protective cover; the power module includes a carrier board, which has an upper surface and a lower surface opposite to each other, as well as a side surface; the side surface of the carrier board is disposed between the upper surface and the lower surface of the carrier board; at least one component is disposed on the upper surface and the lower surface of the carrier board. The motherboard includes an upper surface and a lower surface opposite each other; the upper surface of the motherboard is disposed adjacent to the lower surface of the carrier board; The protective cover includes a lower edge surface and a side surface, the side surface of the protective cover extending from the upper surface of the motherboard to at least the carrier board of the power module; the projected outline of the protective cover on a horizontal plane completely includes the projected outline of the power module on the same horizontal plane; the side surface of the protective cover has an opening structure, the size of at least one dimension of the opening structure being less than 0.15 mm.

2. The immersion heat dissipation structure according to claim 1, wherein The protective cover includes openings on at least two sides, with the area of ​​the opening on one side being greater than 10%.

3. The immersion heat dissipation structure according to claim 2, characterized in that, The opening structure is formed directly by injection molding or by post-processing methods such as mechanical or laser processing.

4. The immersion heat dissipation structure according to claim 1, characterized in that, The protective cover also includes an upper edge surface, the lower edge surface and the upper surface of the motherboard are fixed together by an adhesive material, and the upper edge surface and the carrier plate are fixed together by an adhesive material.

5. The immersion heat dissipation structure according to claim 1, characterized in that, The protective cover includes an upper edge surface that is higher than the upper surface of the carrier plate, and the upper surface of the main board and the inner side of the protective cover are fixed by an adhesive material.

6. The immersion heat dissipation structure according to claim 1, characterized in that, The gap between the protective cover and the motherboard is filled with an adhesive material, and the gap between the protective cover and the carrier board is filled with an adhesive material; the adhesive material is insoluble in immersion coolant; the adhesive material includes silicone, acrylic resin, polyimide, and polyurethane.

7. The immersion heat dissipation structure according to claim 1, characterized in that, The protective cover includes a frame, which is made of insulating material; or the interior of the frame is made of metal, and the surface of the frame is made of insulating material.

8. The immersion heat dissipation structure according to claim 7, characterized in that, The protective cover also includes a skin structure, which is assembled with the frame by any one of bonding, skin tension, or interference fit; the thickness of the skin is less than 500 μm; the opening structure of the skin is formed by laser cutting small holes or photolithography with photosensitive material.

9. The immersion heat dissipation structure according to claim 7, characterized in that, The protective cover also includes a mesh structure, which includes at least one layer of woven mesh, wherein the mesh aperture is less than 0.15 mm in at least one dimension; the mesh material is glass fiber or organic fiber, etc.

10. The immersion heat dissipation structure according to claim 1, characterized in that, The height of the protective cover is greater than the height of the power module, and the protective cover also includes an upper cover plate; the protective cover and the power module are assembled on the motherboard, and the protective cover completely encloses the power module.

11. The immersion heat dissipation structure according to claim 1, characterized in that, The power module also includes an adapter board and a connector. The adapter board has an upper surface and a lower surface facing each other. The connector is disposed between the adapter board and the main board. The lower surface of the adapter board is adjacent to and fixed to the upper surface of the main board.

12. The immersion heat dissipation structure according to claim 11, characterized in that, The protective cover is a mesh structure, and the inner side of the mesh structure is fixedly connected to the side of the carrier plate and the side of the adapter plate.

13. The immersion heat dissipation structure according to claim 11, characterized in that, After the protective cover is fixedly connected to the side of the carrier plate and the side of the adapter plate, the power module is then assembled with the motherboard.

14. The immersion heat dissipation structure according to claim 1, characterized in that, It also includes a metal plate, and the protective cover also includes an upper edge surface. The height of the protective cover is greater than the height of the power module. The metal plate is disposed on the upper edge surface. The metal plate includes an upper surface and a lower surface opposite each other. The lower surface of the metal plate is thermally connected to the heating element in the power module through a thermally conductive interface material, which is a curable thermally conductive material.

15. The immersion heat dissipation structure according to claim 14, characterized in that, The lower surface of the metal plate also includes a step, which is thermally connected to the heating element in the power module through a thermally conductive interface material; the thermally conductive interface material is a curable thermally conductive material.

16. The immersion heat dissipation structure according to claim 14, characterized in that, The metal plate also includes an exhaust hole with a diameter of less than 0.15 mm; the exhaust hole is positioned to avoid contact with the thermal connection area.

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