A heat dissipation method and heat dissipation structure for space high heat consumption optoelectronic equipment

Abstract

The present invention relates to a heat dissipation method and heat dissipation structure of a space-based high-heat-consumption optoelectronic device, (1) taking a chassis as the main heat dissipation path, and performing an optimized heat dissipation design of the chassis; (2) dividing the functional modules packaged as an integrated structure into ordinary functional modules and functional modules with precise temperature control requirements, and performing an optimized heat dissipation design of the functional modules; (3) calculating the equivalent thermal conductivity of a PCB board, performing an optimized heat dissipation design of a PCB board installed in the chassis, strengthening the conduction heat dissipation path between the PCB board and the chassis shell, and optimizing the layout of high-heat-generating components; (4) performing a heat dissipation enhancement design of high-heat-generating components on the PCB board, and improving the heat dissipation effect of the high-heat-generating components. In view of the increasingly high integration of modern electronic equipment, the increasing heat flow of components, the limited layout and installation space, and the large use constraints, the present invention is suitable for the thermal design tasks of heat dissipation and precise temperature control of high-heat-flow components with random spatial distribution layout and limited installation space.

Description

Technical Field

[0001] The invention relates to a heat dissipation method and a heat dissipation structure for a space high-heat-consumption optoelectronic device, belonging to the technical field of thermal design of space equipment. Background Art

[0002] With the rapid development of payload technology, the integration of electronic equipment is getting higher and higher, and the performance requirements are getting higher and higher. The structural size of electronic devices inside the equipment is getting smaller and smaller, and the power consumption is getting larger and larger. The difficulty of heat dissipation design and temperature control of devices has increased significantly. If the thermal design method is improper, it will seriously affect the performance indicators and service life of the equipment, especially space electronic equipment. For example, GEO spacecraft use electronic equipment, which generally needs to operate in orbit for more than 15 years. The reliability of its thermal design method is very important. In electronic products, the impact of high temperature on electronic products includes insulation performance degradation, component damage, thermal aging of materials, cracking of low-melting-point welds and solder joints falling off, which leads to the performance degradation of the entire product and even complete failure. According to statistics, 55% of the failure of electronic equipment is caused by high temperature. As the temperature increases, its failure rate increases exponentially. Electronic components are the basic products of electronic and electrical systems. The temperature of electronic components is an important factor affecting the working reliability of electronic equipment. It can be seen that carrying out thermal design for electronic equipment and components to control the temperature of the selected electronic components within the specified allowable operating temperature range is an effective technical means to ensure and improve their reliability.

[0003] The main heat dissipation path of electronic equipment is to dissipate heat to the outside with the help of the equipment chassis. The commonly used thermal design method is to conduct the heat dissipation of components to the chassis shell through the PCB circuit board installed on it (the PCB board is mechanically connected to the chassis shell). Since the main component of the PCB board is fiberglass or ceramic, the thermal conductivity is low and the heat transfer effect is limited. For high heat consumption and high heat flow devices, in addition to using the PCB board for heat dissipation, it is usually necessary to use heat-conducting metal strips, micro heat pipes, etc. to overlap the components with the chassis shell to strengthen its heat dissipation. This heat dissipation design brings strong restrictions, such as layout, sufficient installation space, etc., and has low safety and reliability, and is not suitable for precise temperature range control. In summary, modern electronic equipment is becoming more and more integrated, the heat flow of components is getting larger and larger, and the layout and installation space are very limited. The existing electronic equipment thermal design technology has great constraints and high design costs. It can no longer be applied to the thermal design task requirements of high heat flow devices with random spatial distribution and limited installation space and precise temperature control. It is urgent to develop new and efficient thermal design methods. Summary of the invention

[0004] The technical problem solved by the present invention is: to overcome the deficiencies of the prior art and provide a heat dissipation method for space-based high-heat-consumption optoelectronic equipment to solve the shortcomings and deficiencies of the prior art that the method is not suitable for heat dissipation and precise temperature control of randomly arranged high-heat-flux components.

[0005] The technical solution adopted by the present invention is:

[0006] A heat dissipation method for a space-based high-heat-consumption optoelectronic device, comprising the following steps:

[0007] (1) The chassis is used as the main path for heat dissipation of equipment functional modules, PCB boards, and components, and the chassis is optimized for heat dissipation design;

[0008] (2) The functional modules packaged in an integrated structure are divided into ordinary functional modules and functional modules with precise temperature control requirements, and the optimized heat dissipation design of the functional modules packaged in an integrated structure in the chassis is performed;

[0009] (3) Calculate the equivalent thermal conductivity of the PCB, optimize the heat dissipation design of the PCB installed in the chassis, strengthen the conduction heat dissipation path between the PCB and the chassis shell, and optimize the layout of high-heat generating components;

[0010] (4) Strengthen the heat dissipation design of high-heat-generating components on the PCB board to improve the heat dissipation effect of high-heat-generating components.

[0011] Furthermore, an optimized heat dissipation design of the chassis is carried out, specifically: the chassis shell structure includes a bottom plate, side plates and a cover plate, all of which are made of aluminum alloy; the bottom plate and the side plates are connected together and milled into an integral structure to reduce the thermal resistance of the heat transfer path; the cover plate is fixed to the upper side of the side plate to close the chassis; the mounting surfaces on both sides of the inside and outside of the chassis bottom plate are full-contact surfaces without weight reduction grooves; the chassis surface is treated with a high-emissivity surface to enhance spatial radiation heat dissipation.

[0012] Furthermore, the high emissivity surface treatment of the chassis surface refers to spraying black paint or black anodizing; the chassis wall thickness is not less than 2.5mm, and the installation surface flatness requirement is that the flatness error within any 100mm×100mm range is less than 0.1mm.

[0013] Furthermore, the optimized heat dissipation design of the functional modules packaged in an integrated structure in the chassis is carried out, specifically:

[0014] For common function modules, they are directly installed on the inner mounting surface of the chassis bottom plate, and heat-conductive fillers are filled between the common function modules and the inner mounting surface of the chassis to enhance contact heat transfer. The common function modules are directly cooled through the chassis.

[0015] Furthermore, for functional modules with precise temperature control requirements, a thermoelectric cooler is first installed on the inner mounting surface of the chassis bottom plate, and then the functional module with precise temperature control requirements is fixed on the thermoelectric cooler. The thermoelectric cooler is used to perform bidirectional heat flow control for heating or cooling the functional module with precise temperature control requirements to achieve precise control of the temperature range; the functional module with precise temperature control requirements is fixed on the thermoelectric cooler by screws or metal clamps, and the thermoelectric cooler is installed on the inner mounting surface of the chassis bottom plate by screws to ensure that all contact surfaces are in close contact, and thermal conductive fillers are filled between all mounting surfaces to enhance contact heat transfer.

[0016] Furthermore, the ordinary functional module refers to a functional module with a minimum operating temperature below 0°C and a maximum operating temperature above 50°C, and the functional module with precise temperature control requirements refers to a laser module, and its operating temperature range is 35±1°C.

[0017] Furthermore, the optimized heat dissipation design of the PCB board installed in the chassis is carried out, specifically:

[0018] Increase the number and thickness of copper clad layers on the PCB board, improve the equivalent thermal conductivity of the PCB board, extend the copper clad layer to the edge of the mounting frame of the circuit board, and clad the outer surface of the mounting frame of the circuit board with copper; increase the local copper clad area and copper clad thickness of the high heat generating component installation area; the high heat generating component refers to a component with a heat consumption ≥ 0.3W;

[0019] The heat is transferred between the components and the PCB board through the contact of the component pins. When meeting the electrical requirements, the length of the component pins should be as short as possible to reduce the conduction thermal resistance. The contact surface between the components and the PCB board is filled with thermal conductive fillers. The width of the contact surface between the PCB board mounting frame and the chassis shell mounting is not less than 5mm. The contact surface is filled with thermal conductive fillers and fixed with screws to strengthen the conduction heat dissipation path between the PCB board and the chassis shell;

[0020] When arranging components, high-heat generating components are placed at the edge of the PCB board to shorten the heat transfer path between the high-heat generating components and the chassis shell; at the same time, high-heat generating components are dispersedly arranged to avoid heat source concentration.

[0021] Furthermore, the equivalent thermal conductivity of the PCB board is calculated as follows:

[0022]

[0023] In the formula, λ 当量 is the equivalent thermal conductivity of the PCB board, λ Cu is the thermal conductivity of the copper cladding layer, λ PCB is the thermal conductivity of the PCB board, H Cu,i is the thickness of the ith copper layer of the PCB board, H PCB,iP is the thickness of the interlayer of the ith board of the PCB; Cu,i is the percentage of copper area of ​​the i-th copper-clad layer of the PCB board; n is the total number of copper-clad layers of the PCB board; m is the total number of interlayer layers of the PCB board.

[0024] Furthermore, the heat dissipation of high-heat generating components on the PCB board is enhanced by:

[0025] The heat dissipation of high-heat generating components on the PCB is enhanced by the heat dissipation panel, the heat dissipation panel and the chassis shell are mechanically connected by screws, and the contact surfaces are filled with thermal conductive fillers; according to the spatial geometric distribution position of the high-heat generating components on the PCB, a structural boss is set at a corresponding projection position on the heat dissipation panel, that is, a structural boss with an adaptation height corresponding to the geometric position of the high-heat generating components is set on the heat dissipation panel, so that the structural boss is in surface contact with the heating surface of the device; a thermal conductive spring pad is padded between the structural boss and the contact surface of the device, and the elastic compression of the thermal conductive spring pad ensures close contact between the three, thereby reducing the contact thermal resistance; an appropriate number of screw mounting interfaces are evenly arranged on the PCB board and the heat dissipation panel around the high-heat generating device, and the contact between the structural boss of the heat dissipation panel, the thermal conductive spring pad, and the heating surface of the device is tightened again by the screws.

[0026] Furthermore, the heat dissipation panel is made of aluminum alloy 6063 material, the width of the connection contact surface between the heat dissipation panel and the chassis shell is not less than 5mm, and the thickness of the thermal conductive pad after compression is less than 0.3mm.

[0027] The present invention also proposes a heat dissipation structure for a space high heat consumption optoelectronic device, comprising: a chassis shell, a common functional module, a thermoelectric cooler, a precision temperature control module, a PCB board, common components, high heat generation components, a thermal conductive spring pad and a heat dissipation panel;

[0028] The chassis shell includes a bottom plate, side plates and a cover plate, all of which are made of aluminum alloy. The bottom plate and the side plates are connected together and milled into an integral structure to reduce the thermal resistance of the heat transfer path. The cover plate is fixed on the upper side of the side plate to close the chassis. The mounting surfaces on both sides of the chassis bottom plate are full-contact surfaces without weight reduction grooves. The chassis surface is treated with a high-emissivity surface to enhance spatial radiation heat dissipation.

[0029] The common function module is directly arranged and installed on the inner mounting surface of the chassis bottom plate, and the heat is directly dissipated through the chassis. A heat conductive filler is filled between the common function module and the inner mounting surface of the chassis to enhance contact heat transfer;

[0030] The thermoelectric cooler is fixedly mounted on the mounting surface on the inner side of the chassis bottom plate, and the precision temperature control module is mounted on the thermoelectric cooler. The thermoelectric cooler is used to perform bidirectional heat flow control of heating or cooling the precision temperature control module, thereby realizing precise control of the temperature range. The precision temperature control module is fixedly mounted on the thermoelectric cooler by screws or metal clamps, and the thermoelectric cooler is mounted on the mounting surface on the inner side of the chassis bottom plate by screws, ensuring that all contact surfaces are in close contact, and thermal conductive fillers are filled between the mounting surfaces to enhance contact heat transfer.

[0031] The PCB board is installed in the chassis shell, the copper clad layer of the PCB board extends to the edge of the circuit board mounting frame, and the outer surface of the circuit board mounting frame is copper-clad, and the area where high-heat generating components are installed on the PCB board is locally processed to increase the copper clad area and increase the thickness of the copper clad layer;

[0032] Ordinary components and high-heat generating components are all placed on the PCB, and heat is transferred between the components and the PCB through the component pins. The contact surface between the components and the PCB is filled with thermal conductive fillers. The width of the contact surface between the PCB mounting frame and the chassis shell mounting is not less than 5mm. Thermal conductive fillers are filled between the contact surfaces and are fixed with screws.

[0033] High-heat generating components are placed at the edge of the PCB board to shorten the heat transfer path between the high-heat generating components and the chassis shell; at the same time, high-heat generating components are dispersedly placed to avoid heat source concentration;

[0034] The heat dissipation of high-heat-generating components on the PCB is enhanced by the heat dissipation panel, the heat dissipation panel and the chassis shell are mechanically connected by screws, and the contact surfaces are filled with thermal conductive fillers; according to the spatial geometric distribution position of the high-heat-generating components on the PCB, a structural boss is arranged at the corresponding projection position on the heat dissipation panel, so that the structural boss is in surface contact with the heating surface of the high-heat-generating component; a thermal conductive spring pad is placed between the structural boss and the contact surface of the high-heat-generating component, and the elastic compression of the thermal conductive spring pad ensures close contact between the three, thereby reducing the contact thermal resistance; screw installation interfaces are evenly arranged on the PCB board and the heat dissipation panel around the high-heat-generating device, and the contact between the structural boss of the heat dissipation panel, the thermal conductive spring pad, and the heating surface of the high-heat-generating device is tightened again by the screws.

[0035] The beneficial effects of the present invention compared with the prior art are:

[0036] (1) The present invention proposes a thermal design method for high heat flux devices of equipment in a space environment. The method has good universality and is widely applicable to the thermal design of space equipment.

[0037] (2) The heat dissipation structure design proposed in the present invention can effectively solve the problem of heat collection, transmission and dissipation of high heat flux devices randomly distributed at multiple points in space. It has the advantages of strong heat transfer capacity, simple structural assembly, high reliability, small design constraints and low cost.

[0038] (3) The thermoelectric cooler (TEC) technology proposed in this invention solves the problem of precise temperature control for modules and components with high temperature precision requirements, and can achieve precise control of the temperature range of 35±1°C. It has the advantages of high temperature control accuracy, low power consumption, small size, light weight, and ease of use. At the same time, the design interface is simplified, which significantly saves thermal design resources.

[0039] (4) The module classification heat dissipation design method proposed in the present invention adopts corresponding thermal control measures according to the module temperature range, which can significantly save design costs.

[0040] (5) The heat dissipation design method proposed in the present invention is based on passive thermal control technologies such as material selection, thermal control coating, and structural design. It has high heat dissipation efficiency and high reliability, and is suitable for the heat dissipation design of long-life space equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a schematic diagram of the heat dissipation design of the space high heat consumption optoelectronic device of the present invention;

[0042] Figure 2 This is a flow chart of the heat dissipation method for space high heat consumption photovoltaic equipment of the present invention. DETAILED DESCRIPTION

[0043] Aiming at the heat dissipation and precise temperature control problems of randomly distributed high heat flux devices in space equipment, a thermal design method is proposed, which takes into account the principle of mechatronic thermal integration design. Figure 2 As shown, the specific method is as follows:

[0044] (1) The chassis is used as the main path for heat dissipation of equipment functional modules, PCB boards, and components, and the chassis is optimized for heat dissipation design;

[0045] The chassis shell is made of low specific gravity and high thermal conductivity materials, and aluminum alloy materials are used in the present invention. The chassis shell structure includes a bottom plate, side plates and a cover plate. The bottom plate and the side plates are connected together and milled into an integral structure to reduce the thermal resistance of the heat transfer path. The cover plate is fixed on the upper side of the side plate to close the chassis; the mounting surfaces on both sides of the chassis bottom plate are full-contact surfaces without weight reduction grooves. The chassis surface is subjected to high-emissivity surface treatment to enhance spatial radiation heat dissipation. The chassis wall thickness is generally not less than 2.5mm, and the flatness requirement of the mounting surfaces on both sides is that the flatness error within any 100mm×100mm range is less than 0.1mm. The chassis surface is subjected to high-emissivity surface treatment (spraying black paint or black anodizing) to enhance spatial radiation heat dissipation.

[0046] (2) The functional modules packaged in an integrated structure are divided into ordinary functional modules and functional modules with precise temperature control requirements, and an optimized heat dissipation design is performed for the functional modules packaged in an integrated structure in the chassis.

[0047] For common function modules, they are directly installed on the inner mounting surface of the chassis bottom plate, and heat-conductive fillers are filled between the common function modules and the inner mounting surface of the chassis to enhance contact heat transfer. The common function modules are directly cooled through the chassis.

[0048] For functional modules with precise temperature control requirements, a thermoelectric cooler (TEC) is first installed on the inner mounting surface of the chassis bottom plate, and then the functional module with precise temperature control requirements is fixed on the thermoelectric cooler. The thermoelectric cooler is used to perform bidirectional heat flow control for heating or cooling the functional module with precise temperature control requirements to achieve precise control of the temperature range; the functional module with precise temperature control requirements is fixed on the thermoelectric cooler by screws or metal clamps, and the thermoelectric cooler is installed on the inner mounting surface of the chassis bottom plate by screws to ensure that all contact surfaces are in close contact, and thermal conductive fillers are filled between all mounting surfaces to enhance contact heat transfer.

[0049] In the present invention, the overall working environment temperature of the optoelectronic device is in the range of 0°C to 50°C. The ordinary functional modules in the chassis generally refer to those having a working temperature range greater than the overall working environment temperature range of the optoelectronic device of 0°C to 50°C, that is, the ordinary functional modules refer to those having a relatively wide working range, such as a functional module with a minimum working temperature below 0°C and a maximum working temperature above 50°C. The functional module with precise temperature control requirements refers to a laser (LD) module, and its working temperature range is very strict, generally 35±1°C.

[0050] (3) Calculate the equivalent thermal conductivity of the PCB, optimize the heat dissipation design of the PCB installed in the chassis, strengthen the conduction heat dissipation path between the PCB and the chassis shell, and optimize the layout of high-heat generating components;

[0051] The components transfer heat to the chassis shell with the help of the PCB board on which they are installed. Under the premise of meeting the electrical performance design, the number and thickness of the copper cladding layers of the PCB board are increased to improve the equivalent thermal conductivity of the PCB board. The copper cladding layer extends to the edge of the mounting frame of the circuit board, and the copper cladding is applied to the outer surface of the mounting frame of the circuit board. In particular, the local copper cladding area or copper cladding thickness of the installation area of ​​high-heat generating components (≥0.3W) is enhanced, and the copper cladding layer extends to the mounting frame of the circuit board. The components and the PCB board are heat-conducted through the contact of the device pins. The contact surface between the components and the PCB board is filled with thermal conductive fillers. The width of the contact surface between the mounting frame of the PCB board and the chassis shell is not less than 5mm. The contact surface is filled with thermal conductive fillers (coated with thermal conductive grease), and screws are used to fix it to strengthen the conduction and heat dissipation path between the PCB board and the chassis shell. The components are arranged reasonably. When arranging the components, the components with high power and high heat generation are arranged at the edge of the PCB board to shorten the heat transfer path between the high-heat generating components and the chassis shell. High-power components should be arranged as dispersed as possible to avoid the concentration of heat sources and optimize the layout of high-heat generating components.

[0052] The equivalent thermal conductivity of the PCB board is calculated as follows:

[0053]

[0054] In the formula, λ 当量 ─Equivalent thermal conductivity of PCB board, unit: W / (m·k);

[0055] λ Cu ─Thermal conductivity of copper in the copper cladding layer, unit: W / (m·k);

[0056] λ PCB ─PCB board thermal conductivity, unit: W / (m·k);

[0057] H Cu,i ─Thickness of the i-th copper layer of the PCB board, unit: m;

[0058] H PCB,i ─Thickness of the interlayer of the ith sheet of the PCB board, unit: m;

[0059] P Cu,i ─Percentage of copper area of ​​the ith copper layer of the PCB board, unit: %;

[0060] n─Total number of copper layers on PCB board, unit: layer;

[0061] m─Total number of interlayers of PCB board, unit: layer.

[0062] (4) Strengthen the heat dissipation design of high-heat-generating components on the PCB board to improve the heat dissipation effect of high-heat-generating components.

[0063] Aiming at the randomly distributed high heat dissipation and high heat flow components on the PCB board, a special heat dissipation panel is designed as a heat collection and transmission device to achieve remote and efficient heat dissipation of the randomly distributed high heat dissipation and high heat flow components in space.

[0064] Specific thermal design: A heat dissipation panel is designed on the heating surface of the components on the PCB board. The heat dissipation panel is made of low specific gravity and high thermal conductivity aluminum alloy (6063). The heat dissipation panel and the chassis shell structure are mechanically connected by screws. The width of the connection contact surface is not less than 5mm, and the contact surface is filled with thermal conductive fillers. According to the spatial geometric distribution position of the high-heat-generating components on the PCB board, the structural boss shaping design is performed on the corresponding projection position on the heat dissipation panel, that is, a structural boss of an adaptive height corresponding to the geometric position of the high-heat-generating components is designed on the heat dissipation panel so that it contacts the heating surface of the device. For details, see Figure 1Considering the design of processing and assembly clearance, a thermally conductive spring pad (Sil-Pad 2000 series is recommended) with a thickness of less than 0.3mm (after compression) is placed between the structural boss and the device contact surface. The elastic compression of the thermally conductive spring pad ensures close contact between the three and reduces contact thermal resistance.

[0065] An appropriate number of screw mounting interfaces are evenly distributed on the PCB and heat dissipation panel around the high-heat-generating device, and the screws are used to tighten the close contact between the heat dissipation structure boss, the thermal spring pad, and the device's heating surface. Lightening holes or grooves can be opened in the non-main heat transfer path of the heat dissipation panel according to weight reduction requirements.

[0066] According to the heat dissipation method designed above, a heat dissipation structure of a space high heat consumption optoelectronic device is realized, such as Figure 1 As shown, it includes: a chassis shell 1, a common functional module 2, a thermoelectric cooler 3, a precision temperature control module 4, a PCB board 5, common components 6, high-heat generating components 7, a thermal conductive pad 8 and a heat dissipation panel 9;

[0067] The chassis shell 1 includes a bottom plate, a side plate and a cover plate, all of which are made of aluminum alloy. The bottom plate and the side plate are connected together and milled into an integral structure to reduce the thermal resistance of the heat transfer path. The cover plate is fixed on the upper side of the side plate to close the chassis. The mounting surfaces on both sides of the chassis bottom plate are full contact surfaces without weight reduction grooves. The chassis surface is treated with a high emissivity surface to enhance spatial radiation heat dissipation.

[0068] The common function module 2 is directly arranged and installed on the inner mounting surface of the chassis bottom plate, and the heat is directly dissipated through the chassis. A heat conductive filler is filled between the common function module and the inner mounting surface of the chassis to enhance contact heat transfer;

[0069] The thermoelectric cooler 3 is fixedly mounted on the mounting surface on the inner side of the chassis bottom plate, and the precision temperature control module 4 is mounted on the thermoelectric cooler 3. The thermoelectric cooler 3 performs bidirectional heat flow control of heating or cooling the precision temperature control module 4 to achieve precise control of the temperature range; the precision temperature control module 4 is fixed on the thermoelectric cooler 3 by screws or metal clamps, and the thermoelectric cooler 3 is mounted on the mounting surface on the inner side of the chassis bottom plate by screws to ensure that all contact surfaces are in close contact, and heat conductive fillers are filled between the mounting surfaces to enhance contact heat transfer;

[0070] The PCB board 5 is installed in the chassis housing 1, the copper clad layer of the PCB board 5 extends to the edge of the circuit board mounting frame, and is copper clad on the outer surface of the circuit board mounting frame, and the area on the PCB board 5 where high heat generating components are installed is locally processed to increase the copper clad area and increase the thickness of the copper clad layer;

[0071] The common components 6 and the high-heat generating components 7 are both arranged on the PCB board 5, and heat is transferred between the components and the PCB board 5 through the component pins. The contact surface between the components and the PCB board is filled with heat-conducting fillers. The width of the contact surface between the mounting frame of the PCB board 5 and the mounting contact surface of the chassis shell is not less than 5mm. The contact surface is filled with heat-conducting fillers and is fixed with screws.

[0072] The high-heat generating components 7 are arranged at the edge of the PCB board 5, shortening the heat transfer path between the high-heat generating components 7 and the chassis housing 1; at the same time, the high-heat generating components 7 are arranged in a dispersed manner to avoid the concentration of heat sources;

[0073] The heat dissipation of the high-heat-generating components 7 on the PCB board is enhanced by the heat dissipation panel 9, the heat dissipation panel 9 and the chassis shell 1 are mechanically connected by screws, and the contact surfaces are filled with thermal conductive fillers; according to the spatial geometric distribution position of the high-heat-generating components 7 on the PCB board, a structural boss is set at the corresponding projection position on the heat dissipation panel 9, so that the structural boss is in contact with the heating surface of the high-heat-generating component 7; a thermal conductive spring pad 8 is padded between the structural boss and the contact surface of the high-heat-generating component 7, and the elastic compression of the thermal conductive spring pad 8 ensures close contact between the three, thereby reducing the contact thermal resistance; screw installation interfaces are evenly arranged on the PCB board 5 and the heat dissipation panel 9 around the high-heat-generating component 7, and the contact between the structural boss of the heat dissipation panel 9, the thermal conductive spring pad 8, and the heating surface of the high-heat-generating component 7 is tightened again by screws.

[0074] Example:

[0075] The method of the present invention is applied to conduct thermal design for a certain satellite optoelectronic device, which is mainly composed of a power module, an EDFA (erbium-doped fiber amplifier) ​​module, an LD (laser) module, a data processing board, an optical signal transceiver control board, a high-power FPGA device, etc. The thermal design is specifically implemented as follows:

[0076] (1) Chassis thermal design

[0077] The chassis shell structure material is aluminum alloy (6063 aluminum alloy plate), and adopts a six-sided box structure design. The chassis installation base plate is 3.5mm thick, and the other 5 panels are 2.5mm thick. Except for the top cover plate, the other 4 side panels and the bottom plate are milled into an integral structure to reduce the heat transfer resistance between the side panels and the bottom plate. The mounting surfaces on both sides of the bottom plate are full contact surfaces without weight reduction grooves. The flatness requirement of the mounting surface is that the flatness error within any 100mm×100mm range is less than 0.1mm. The overlap width of the top cover plate and each side panel connected to it is 10mm, and they are installed by screw connection. Thermal grease is applied between the contact surfaces of all interconnected panels of the chassis shell structure to reduce the contact thermal resistance.

[0078] The outer surface of the chassis is black anodized or sprayed with black paint (surface emissivity ≥ 0.85) to enhance radiant heat dissipation.

[0079] (2) Module thermal design

[0080] The power module, EDFA module and other modules are directly installed on the inner surface of the chassis bottom panel by screws, and thermal grease is applied between the installation contact surfaces of all modules to reduce the contact thermal resistance. The outer surface of the module (except the installation surface) is black anodized or sprayed with black paint (surface emissivity ≥ 0.85) to enhance radiation heat dissipation.

[0081] The LD (laser) module has a requirement for precise temperature control (35±1℃), and a TEC (thermoelectric cooler) is used to control its temperature. The hot surface of the LD module is installed on the upper surface (cold surface) of the TEC, while the lower surface (heat dissipation surface) of the TEC is directly installed on the inner surface of the bottom panel of the chassis through screws, and the LD module is pressed and fixed to the upper surface of the TEC with a copper clamp. The two ends of the copper clamp are fixed to the bottom plate of the chassis with screws. Thermal grease is coated between all installation contact surfaces to reduce contact thermal resistance.

[0082] (3) PCB thermal design

[0083] The thickness of the PCB circuit board (data processing board, optical signal transceiver control board) is about 2mm, and the board is made of epoxy glass cloth. In order to improve the heat conduction path between the PCB board and the chassis shell and provide a good heat dissipation channel for the components, the following measures are taken during the circuit board design:

[0084] 1) Under the premise of meeting the electrical performance design, the PCB board is covered with 8 layers of copper with different thicknesses, see Table 1 for details.

[0085] Table 1 Copper layer inside PCB circuit board

[0086] Number of layers Copper layer thickness (μm) Copper Covering Area Percentage (%) Remark 1 70 79.56 2 35 94.28 3 35 83.16 4 35 90 5 35 90 6 35 90 7 35 90 8 70 91.48

[0087] 2) The inner copper layer extends to the edge of the circuit board mounting frame and is copper-clad on the outer surface of the circuit board mounting frame.

[0088] 3) Increase the local copper cladding area or copper cladding thickness of the high heat generating component (≥0.3W) installation area, and extend the copper cladding layer to the installation frame of the circuit board. In this embodiment, the high heat generating component is an FPGA chip.

[0089] 4) The contact surface width between the PCB circuit board mounting frame and the chassis structure mounting boss is 10mm. It is fixed by screws and the mounting contact surface is coated with thermal grease.

[0090] According to formula (1), the equivalent thermal conductivity of the PCB circuit board is about 52.5W / (m·k).

[0091] (4) Component thermal design

[0092] When designing the layout of components on the PCB, high-power and high-heat generating components (FPGA chips) should be placed on the edge of the PCB board frame, provided that the circuit design allows, to shorten the heat transfer path between the FPGA chip and the chassis shell. Components should be dispersed and distributed as evenly as possible, especially high-power and high-heat generating components, to avoid heat source concentration. When installing components on the PCB board, the length of the mounting pins should be as short as possible, and thermally conductive silicone rubber should be applied between the mounting surface of the components that generate heat and the PCB board to reduce the thermal resistance of heat transfer.

[0093] For the randomly distributed high-heat generating components on the PCB, a heat dissipation panel is designed as a heat collection and transmission enhancement device to achieve remote heat dissipation of point heat sources randomly distributed in space. A heat dissipation panel structure is designed on the heating surface of the components on the PCB. The heat dissipation panel is made of low specific gravity and high thermal conductivity aluminum alloy (6063 aluminum alloy plate). The heat dissipation panel structure is mechanically connected to the chassis shell structure by screws. The width of the connection contact surface is 10mm, and thermal grease is filled between the contact surfaces.

[0094] According to the spatial geometric distribution position of high heat generating components on the PCB board, the structural boss is designed at the corresponding projection position on the heat dissipation panel. The geometric center of the structural boss coincides with the geometric center of the high heat generating component connected to it. The outer contour of the boss is 5mm larger than the outer contour of the heating surface of the component. The height of the boss is designed to match the height of the high heat generating component connected to it.

[0095] Considering processing and assembly, a gap of 0.2mm to 0.3mm is left. During assembly, a Sil-Pad 2000 series thermal pad with a thickness of less than 0.3mm (after compression) is placed between the structural boss and the contact surface of the component. The elastic compression of the thermal pad ensures close contact between the three and reduces the contact thermal resistance. In order to ensure close and stable contact between the structural boss, thermal pad and components, two screw installation interfaces are evenly designed on the PCB board around the component and the corresponding heat dissipation panel. The screws are used to tighten the structural boss, thermal pad and the heating surface of the component again to ensure close contact and reduce the contact heat transfer thermal resistance.

[0096] After completing the above thermal design and implementation, the space flight working environment (cold black, vacuum, hot environment) and working mode of the equipment were simulated in the space environment simulator, and the heat dissipation method was verified by thermal tests. The verification results show that all modules meet the operating temperature range, and the LD (laser) module temperature is controlled within 35±1°C; all components meet the first-level temperature derating requirements and still have more than 20% margin. Among them, the temperature of the high-heat FPGA (heat consumption 10W) ​​has a margin of about 15°C from the first-level derating temperature, and the heat dissipation effect of the heat dissipation panel structure is good.

[0097] The contents not described in detail in the specification of the present invention belong to the well-known technologies of professionals in the field.

Claims

1. A method for heat dissipation of a space-based high-heat-consumption photovoltaic device, characterized in that Here are the steps: (1) The chassis is used as the main path for heat dissipation of equipment functional modules, PCB boards, and components, and the chassis is optimized for heat dissipation design; (2) The functional modules packaged in an integrated structure are divided into ordinary functional modules and functional modules with precise temperature control requirements, and the optimized heat dissipation design of the functional modules packaged in an integrated structure in the chassis is performed; (3) Calculate the equivalent thermal conductivity of the PCB, optimize the heat dissipation design of the PCB installed in the chassis, strengthen the conduction heat dissipation path between the PCB and the chassis shell, and optimize the layout of high-heat generating components; (4) Strengthen the heat dissipation design of high-heat generating components on the PCB board to improve the heat dissipation effect of high-heat generating components; Optimize the heat dissipation design of the functional modules packaged in an integrated structure in the chassis, specifically: For common function modules, they are directly installed on the inner mounting surface of the chassis bottom plate, and heat-conductive fillers are filled between the common function modules and the inner mounting surface of the chassis bottom plate to enhance contact heat transfer. The common function modules are directly cooled through the chassis; For functional modules with precise temperature control requirements, a thermoelectric cooler is first installed on the inner mounting surface of the chassis bottom plate, and then the functional module with precise temperature control requirements is fixed on the thermoelectric cooler. The thermoelectric cooler is used to perform bidirectional heat flow control of heating or cooling the functional module with precise temperature control requirements to achieve precise control of the temperature range; the functional module with precise temperature control requirements is fixed on the thermoelectric cooler by screws or metal clamps, and the thermoelectric cooler is installed on the inner mounting surface of the chassis bottom plate by screws to ensure that all contact surfaces are in close contact, and thermal conductive fillers are filled between all mounting surfaces to enhance contact heat transfer; Optimize the heat dissipation design of the PCB board installed in the chassis, specifically: Increase the number and thickness of copper clad layers on the PCB board, improve the equivalent thermal conductivity of the PCB board, extend the copper clad layer to the edge of the mounting frame of the circuit board, and clad the outer surface of the mounting frame of the circuit board with copper; increase the local copper clad area and copper clad thickness of the high heat generating component installation area; the high heat generating component refers to a component with a heat consumption ≥ 0.3W; The components and PCB board are in contact with each other through the component pins. The contact surface between the components and the PCB board is filled with thermal conductive fillers. The width of the contact surface between the PCB board mounting frame and the chassis shell mounting is not less than 5mm. The contact surface is filled with thermal conductive fillers and fixed with screws to strengthen the conduction heat dissipation path between the PCB board and the chassis shell. When arranging components, high-heat generating components are placed at the edge of the PCB board to shorten the heat transfer path between the high-heat generating components and the chassis shell; at the same time, high-heat generating components are dispersedly arranged to avoid heat source concentration; Strengthen the heat dissipation design of high heat generating components on PCB boards, specifically: The heat dissipation of high-heat generating components on the PCB is enhanced by the heat dissipation panel, the heat dissipation panel and the chassis shell are mechanically connected by screws, and the contact surfaces are filled with thermal conductive fillers; according to the spatial geometric distribution position of the high-heat generating components on the PCB, a structural boss is set at a corresponding projection position on the heat dissipation panel, that is, a structural boss with an adaptation height corresponding to the geometric position of the high-heat generating components is set on the heat dissipation panel, so that the structural boss is in surface contact with the heating surface of the device; a thermal conductive spring pad is padded between the structural boss and the contact surface of the device, and the elastic compression of the thermal conductive spring pad ensures close contact between the three, thereby reducing the contact thermal resistance; an appropriate number of screw mounting interfaces are evenly arranged on the PCB board and the heat dissipation panel around the high-heat generating device, and the contact between the structural boss of the heat dissipation panel, the thermal conductive spring pad, and the heating surface of the device is tightened again by the screws.

2. The heat dissipation method for a space-based high-heat-consumption photovoltaic device according to claim 1, characterized in that: The chassis is designed to optimize heat dissipation. Specifically, the chassis shell structure includes a bottom plate, side plates and a cover plate, all of which are made of aluminum alloy. The bottom plate and the side plates are connected together and milled into an integral structure to reduce the thermal resistance of the heat transfer path. The cover plate is fixed on the upper side of the side plate to close the chassis. The mounting surfaces on both sides of the chassis bottom plate are full-contact surfaces without weight reduction grooves. The chassis surface is treated with a high-emissivity surface to enhance spatial radiation heat dissipation.

3. The heat dissipation method for space-based high heat consumption photovoltaic equipment according to claim 2, characterized in that: High emissivity surface treatment on the chassis surface refers to spraying black paint or black anodizing; the chassis wall thickness is not less than 2.5mm, and the installation surface flatness requirement is that the flatness error within any 100mm×100mm range is less than 0.1mm.

4. The heat dissipation method for space-based high heat consumption photovoltaic equipment according to claim 1, characterized in that: The ordinary functional module refers to a functional module with a minimum operating temperature below 0°C and a maximum operating temperature above 50°C, and the functional module with precise temperature control requirements refers to a laser module, and its operating temperature range is 35±1°C.

5. The heat dissipation method for space-based high-heat-consumption photovoltaic equipment according to claim 1, characterized in that: The equivalent thermal conductivity of the PCB board is calculated as follows: In the formula, λ 当量 is the equivalent thermal conductivity of the PCB board, λ Cu is the thermal conductivity of the copper cladding layer, λ PCB is the thermal conductivity of the PCB board, H Cu,i is the thickness of the ith copper layer of the PCB board, H PCB,i P is the thickness of the interlayer of the ith board of the PCB; Cu,i is the percentage of copper area of ​​the i-th copper-clad layer of the PCB board; n is the total number of copper-clad layers of the PCB board; m is the total number of interlayers of the PCB board.

6. The heat dissipation method for space-based high-heat-consumption photovoltaic equipment according to claim 1, characterized in that: The heat dissipation panel is made of aluminum alloy 6063 material. The width of the connection contact surface between the heat dissipation panel and the chassis shell is not less than 5mm, and the thickness of the thermal conductive pad after compression is less than 0.3mm.

7. A heat dissipation structure of a space high heat consumption photovoltaic device implemented by the heat dissipation method of space high heat consumption photovoltaic device according to claim 1, characterized in that include: A chassis shell (1), a common functional module (2), a thermoelectric cooler (3), a precision temperature control module (4), a PCB board (5), common components (6), high-heat generating components (7), a thermally conductive spring pad (8), and a heat dissipation panel (9); The chassis shell (1) comprises a bottom plate, a side plate and a cover plate, all of which are made of aluminum alloy material. The bottom plate and the side plate are connected together and milled into an integral structure to reduce the thermal resistance of the heat transfer path. The cover plate is fixed on the upper side of the side plate to close the chassis. The mounting surfaces on both sides of the chassis bottom plate are full-contact surfaces without weight-reducing grooves. The chassis surface is treated with a high-emissivity surface to enhance spatial radiation heat dissipation. The common function module (2) is directly arranged and installed on the inner mounting surface of the chassis bottom plate, and the heat is directly dissipated through the chassis. A heat conductive filler is filled between the common function module and the inner mounting surface of the chassis to enhance contact heat transfer; The thermoelectric cooler (3) is fixedly mounted on the mounting surface on the inner side of the chassis bottom plate, and the precision temperature control module (4) is mounted on the thermoelectric cooler (3). The thermoelectric cooler (3) performs bidirectional heat flow control on the precision temperature control module (4) to heat or cool, thereby realizing precise control of the temperature range. The precision temperature control module (4) is fixedly mounted on the thermoelectric cooler (3) by screws or metal clamps, and the thermoelectric cooler (3) is mounted on the mounting surface on the inner side of the chassis bottom plate by screws, ensuring that all contact surfaces are in close contact, and filling heat conductive fillers between the mounting surfaces to enhance contact heat transfer. The PCB board (5) is installed in the chassis housing (1), the copper clad layer of the PCB board (5) extends to the edge of the circuit board mounting frame, and is copper clad on the outer surface of the circuit board mounting frame, and the area on the PCB board (5) where high heat generating components are installed is locally treated to increase the copper clad area and increase the thickness of the copper clad layer; The common components (6) and the high-heat generating components (7) are both mounted on the PCB (5), and heat is transferred between the components and the PCB (5) through the component pins; the contact surface between the components and the PCB is filled with heat-conducting filler; the width of the contact surface between the mounting frame of the PCB (5) and the mounting contact surface of the chassis shell is not less than 5 mm; the contact surface is filled with heat-conducting filler, and screws are used for mounting and fixing; The high-heat generating components (7) are arranged at the edge of the PCB board (5), shortening the heat transfer path between the high-heat generating components (7) and the chassis housing (1); at the same time, the high-heat generating components (7) are arranged in a dispersed manner to avoid the concentration of heat sources; The heat dissipation of the high-heat-generating components (7) on the PCB is enhanced by a heat dissipation panel (9); the heat dissipation panel (9) and the chassis shell (1) are mechanically connected by screws, and heat-conducting fillers are filled between the contact surfaces; according to the spatial geometric distribution position of the high-heat-generating components (7) on the PCB, a structural boss is arranged at a corresponding projection position on the heat dissipation panel (9), so that the structural boss is in surface contact with the heating surface of the high-heat-generating components (7); a heat-conducting spring pad (8) is placed between the structural boss and the contact surface of the high-heat-generating components (7), and the elastic compression of the heat-conducting spring pad (8) ensures close contact between the three, thereby reducing contact thermal resistance; screw installation interfaces are evenly arranged on the PCB board (5) and the heat dissipation panel (9) around the high-heat-generating components (7), and the contact between the structural boss of the heat dissipation panel (9), the heat-conducting spring pad (8), and the heating surface of the high-heat-generating components (7) is tightened again by the screws.

8. The heat dissipation structure of space-based high-heat-consumption photovoltaic equipment according to claim 7, characterized in that: The high emissivity surface treatment of the chassis surface refers to spraying black paint or black anodizing; the chassis wall thickness is not less than 2.5mm, and the flatness requirement of the installation surface is that the flatness error within any 100mm×100mm range is less than 0.1mm; the high heat generation components refer to components with heat consumption ≥0.3W; The common function module (2) refers to a function module with a minimum operating temperature below 0°C and a maximum operating temperature above 50°C, and the precision temperature control module (4) refers to a laser module with an operating temperature range of 35±1°C; The heat dissipation panel is made of aluminum alloy 6063 material. The width of the connection contact surface between the heat dissipation panel and the chassis shell is not less than 5mm, and the thickness of the thermal conductive pad after compression is less than 0.3mm.

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