Phase change cold plate based on penetrating friction welding

Abstract

The present application provides a phase change cold plate based on penetrating friction welding, comprising a box body, a cover plate and a phase change layer plate, wherein a sink groove structure is arranged in the box body, an inner wall of the sink groove structure is provided with an overlapping step, a plurality of reinforcing ribs are arranged at the bottom of the sink groove structure, and the reinforcing ribs divide the sink groove structure into a plurality of unit cavities, the phase change layer plate comprises a plurality of phase change blocks, each phase change block is arranged in each unit cavity, a small reinforcing rib is arranged at the upper end of the large reinforcing rib, a plurality of upper grooves are arranged on the lower end surface of the cover plate, the edge of the cover plate is placed on the overlapping step, and the small reinforcing ribs are inserted into the upper grooves, thereby solving the problem that the center of the cold plate is easily deformed by force and the structural strength is low when only welding the seams in the traditional method.

Description

Technical Field

[0001] The utility model relates to the field of phase change cold plates, in particular to a phase change cold plate based on penetrating friction welding. Background Art

[0002] Phase change temperature control technology uses the latent heat absorption characteristics of phase change materials to absorb a large amount of heat during the phase change process while keeping the temperature basically unchanged. This characteristic makes phase change temperature control technology have significant advantages in dealing with the heat dissipation problem of high power density components. Phase change temperature control technology is passive, does not require external energy, has good heat dissipation effect, and has stable temperature control. It can reduce noise, energy consumption and space occupation while ensuring heat dissipation effect.

[0003] Phase change temperature control technology usually achieves temperature control in the form of a phase change cold plate, which consists of a metal shell and a phase change material filled inside. When designing the structure of the phase change cold plate, it is necessary to ensure the structural strength to avoid bulging and deformation of the cold plate due to the volume change of the phase change material during the phase change. At the same time, the heat storage capacity should be maximized as much as possible to fill more phase change material. In order to prevent leakage of the phase change material, the phase change cold plate is usually welded.

[0004] As a solid phase welding method, stir friction welding has the advantages of high welding quality and high operating efficiency. No filling materials or protective gas are required during the welding process, and no pretreatment of the weld surface is required before welding. It has small residual stress, excellent weld structure, and strong welding ability, which is particularly suitable for the welding of phase change cold plates. The stir friction welding process usually only welds the contact gap of metal parts and cannot guarantee good structural strength. Therefore, it is urgent to find a new welding process that can ensure the good structural strength of the cold plate and also ensure that the cold plate has the maximum heat storage capacity. Utility Model Content

[0005] The utility model provides a phase change cold plate based on penetrating friction welding, which solves the problem that the center of the cold plate is easily deformed by force and has low structural strength when only the joints are welded in the traditional method.

[0006] In order to solve the above technical problems, the technical solution adopted by the utility model is: a phase change cold plate based on penetrating friction welding, including a box body, a cover plate and a phase change layer plate, a sink groove structure is provided in the box body, the inner wall of the sink groove structure is provided with an overlapping step, and a plurality of reinforcing ribs are provided at the bottom of the sink groove structure. The reinforcing ribs divide the sink groove structure into a plurality of unit cavities, and the phase change layer plate includes a plurality of phase change blocks, each phase change block is arranged in each unit cavity, a small reinforcing rib is provided at the upper end of the large reinforcing rib, and a plurality of upper grooves are provided on the lower end surface of the cover plate, the edge of the cover plate is placed on the overlapping step, and the small reinforcing ribs are inserted into the upper grooves.

[0007] In a preferred solution, at least two positioning holes are provided on the cover plate, and at least two positioning posts are provided on the reinforcing ribs, and the positioning posts are inserted into the positioning holes.

[0008] In a preferred solution, a plurality of reinforcing ribs are arranged transversely and longitudinally to form a grid structure, and the positioning columns are arranged at the intersection nodes of the grid structure.

[0009] In the preferred solution, the lower end surface of the cover plate is also provided with multiple upper raised ribs, and the unit cavity is provided with multiple lower raised ribs. Each phase change block is provided with an upper groove body and a lower groove body on the upper and lower sides respectively, and the upper raised ribs are embedded in the upper groove body, and the lower raised ribs are embedded in the lower groove body.

[0010] In a preferred embodiment, the sum of the heights of the lower raised rib and the upper raised rib is lower than the height of the reinforcing rib.

[0011] In a preferred solution, the end surface of the cover plate is flush with the end surface of the box body.

[0012] Fill the processed phase change material into the cold plate shell and cover it with a cover plate;

[0013] Place the cold plate at the preset position of the welding platform and fix the position of the cold plate;

[0014] A friction stir welding tool is used to perform penetration welding on the middle docking position of the cold plate shell and the cover plate at a preset speed, and a friction stir welding tool is used to weld the surrounding docking positions of the cold plate shell and the cover plate at a preset speed to obtain a phase change cold plate after friction stir welding.

[0015] According to the above solution, the cold plate shell and the cover plate are made of 6xxx series aluminum alloy or 2xxx series aluminum alloy.

[0016] According to the above scheme, the structure of the cold plate shell and the cover plate is shown in the figure, which consists of a lap step, a large reinforcing rib, a small reinforcing rib, and a groove. The width of the lap step is 0.5-1mm larger than the radius of the stirring needle tip. The width of the large reinforcing rib is 1-2mm larger than the diameter of the stirring needle tip, and the height is consistent with the lap step. The width of the small reinforcing rib is 0.8-1mm, and the height is 0.5-3mm. The thickness of the bottom surface of the groove is 0.8-1.5mm, and the width and depth are consistent with the small reinforcing rib.

[0017] According to the above scheme, a small-sized stirring head is selected for the friction stir welding tool to meet the maximum filling amount of the phase change material. The selectable stirring head needle tip diameter ranges from 2 to 4 mm, the needle length ranges from 2.0 to 4.0 mm, and the shaft shoulder diameter ranges from 5.5 to 8 mm.

[0018] According to the above scheme, the preset rotation speed is 2000-2500 rpm and the welding speed is 100-120 mm / min.

[0019] Fill the processed phase change material into the cold plate shell and cover it with a cover plate;

[0020] It should be noted that when filling the phase change material, it is necessary to avoid the phase change material from sticking to the overlapping steps, and to prevent the phase change material from being rolled into the welding position when the stirring head is stirring, which will affect the welding quality. The thickness of the phase change material should be 0.02-0.05mm larger than the depth of the cold plate shell, in order to make the phase change material fit closely with the shell, reduce the air thermal resistance, and improve the comprehensive thermal conductivity.

[0021] The cold plate shell and cover plate are processed and formed according to the design drawings. Before welding, the shell and cover plate need to be cleaned with alcohol, and then dried with a hair dryer to remove oil or other impurities on the surface of the workpiece. These impurities are very likely to form mixed particles during the welding process, resulting in a decrease in the quality of the joint connection. In addition, it should be dried after cleaning and welded in time, because residual moisture is easy to form oxide particles during the welding process, and if welding is not performed in time after cleaning, a new oxide film will be formed, thereby reducing the quality and performance of the joint connection. Therefore, this step is mainly to remove oxide films, oil stains and other impurities, and dry them, thereby improving the connection quality and performance of the joint.

[0022] In this step, the cold plate cover is placed on top of the shell, ensuring that the structural reinforcement ribs are embedded in the grooves of structure 4. To ensure that the upper surface of the shell and the upper surface of the cover are on the same plane after the cover is completed, a rubber hammer can be used to manually tap the docking position. It should be noted that since the cover of some examples is thin, using a hammer to tap may cause cracks or breakage in the cover, affecting welding, so the cover is fixed by manually tapping with a rubber hammer.

[0023] Place the cold plate at the preset position of the welding platform and fix the position of the cold plate;

[0024] A friction stir welding tool is used to perform penetration welding on the middle docking position of the cold plate shell and the cover plate at a preset speed, and a friction stir welding tool is used to weld the surrounding docking positions of the cold plate shell and the cover plate at a preset speed to obtain a phase change cold plate after friction stir welding.

[0025] In the above steps, the friction stir welding tool selects a small-sized stirring head to meet the maximum filling amount of the phase change material. The selectable stirring head needle end diameter range is 2-3mm, the needle length range is 2.0-4.0mm, the welding depth is 0.1-0.2mm longer than the needle length, and the shoulder diameter range is 5.5-6.5mm. The size of the stirring head must be within a certain range. An oversized stirring head generates more heat when rotating, which will cause the phase change material to melt or even vaporize, further causing the phase change material to flow into the welding area, affecting the welding quality. At the same time, in order to match the large stirring head, the size of the large ribs and small ribs in the cold plate structure design will increase accordingly, and the corresponding space for filling the phase change material will be reduced, and the heat storage capacity of the entire cold plate will be reduced, affecting the heat storage performance of the cold plate; too small a stirring head generates too little heat when rotating, resulting in insufficient heat during welding, which makes the bottom of the joint poor in fluidity, forming a bottom defect, and leaking after the phase change of the phase change material in the subsequent use process.

[0026] In the above steps, during penetration welding, the width of the rib is 1-2mm larger than the diameter of the root of the stirring needle, and the rib width must be within a certain range. If the rib width is too small, the heat generated by the rotation of the stirring head will be transferred to the phase change material filled inside, causing the phase change material to melt or even vaporize, further causing the phase change material to flow into the welding area, affecting the welding quality. At the same time, after the phase change material is lost, the heat storage capacity of the entire cold plate is reduced, affecting the heat storage performance of the cold plate; if the rib width is too large, the space that can be filled with phase change material inside will become smaller, and the heat storage capacity of the cold plate will decrease.

[0027] In the above steps, the shoulder of the stirring head is controlled to apply pressure to the top surface of the aluminum alloy plate during welding, and the downward pressure is 0.1-0.2mm. The downward pressure must be within a certain range. Too much downward pressure will lead to excessive heat input, causing the phase change material to melt or even vaporize, further causing the phase change material to flow into the welding area, affecting the welding quality. At the same time, after the phase change material is lost, the heat storage capacity of the entire cold plate is reduced, affecting the heat storage performance of the cold plate; while too little downward pressure will lead to insufficient heat during welding, resulting in poor fluidity at the bottom of the joint, forming a bottom defect, and leakage after the phase change material changes in the subsequent use.

[0028] In the above steps, the middle area must be penetrated and welded first, and then the surrounding area is welded. The purpose is to prevent the cover from lifting due to the pressure of the stirring head when welding around the periphery, which affects the welding quality.

[0029] In the above steps, the rotation speed of the stirring head is 2000-2500 rpm and the welding speed is 100-120 mm / min during penetration welding. The rotation speed is within the above range mainly to ensure that the cold plate material for welding has suitable plastic flow ability and prevent excessive wear of the tool, thereby achieving a good connection. However, too low a rotation speed leads to too low a heat input and cannot achieve a good connection; too high a rotation speed leads to too high a heat input, which causes excessive softening of the material and tunnel defects on the weld surface.

[0030] The beneficial effects of the utility model are as follows: compared with the traditional method of welding only the contact gap between two workpieces, through the multi-compartment design, there are multiple welding strips in the central area of ​​the box body and the cover plate, the structural strength is higher, and the cold plate will not be deformed and bulged due to the volume expansion caused by the phase change of the phase change material;

[0031] Compared with the block welding after splitting the cover plate into multiple small cover plates, the welding method is simpler and can be formed by welding in one time. At the same time, the volume occupied is smaller, the filling amount of phase change material can be guaranteed, and the flatness of the surface after welding is also better than the block welding.

[0032] The narrow width of the reinforcing ribs can save design space and use more space to fill the phase change material to ensure the maximum heat storage of the cold plate. At the same time, only a small-sized stirring head is needed for welding. The heat generated during welding is lower than that of a large-sized stirring head, which can prevent the internal phase change material from gasifying due to excessive temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0034] Figure 1 It is a schematic diagram of the simple structure of the cold plate.

[0035] Figure 2 It is a schematic diagram of the box.

[0036] Figure 3 It is a schematic diagram of the bottom side of the cover.

[0037] Figure 4 This is a schematic diagram of penetration welding.

[0038] Figure 5 It is a schematic diagram of the cold plate structure with bottom reinforcement ribs.

[0039] Figure 6 It is a schematic diagram of the structure with reinforcing ribs on the bottom side of the cover plate.

[0040] Figure 7 It is a schematic diagram of the phase change block cutting groove.

[0041] Figure 8 It is a schematic diagram of the cold plate B structure.

[0042] Fig. 9 It is a schematic diagram of the cold plate C structure.

[0043] Fig.10 It is a cold plate temperature-time comparison curve.

[0044] Fig.11 It is a schematic diagram of a cover plate with an inserted seam type cold plate.

[0045] Fig.12 This is a structural diagram of a cover plate with an inserted seam type cold plate.

[0046] Fig.13 This is a schematic diagram of the avoidance groove.

[0047] Fig.14 It is a schematic diagram of the connected groove.

[0048] Fig.15 This is the path diagram of the large stirring head rotary friction welding.

[0049] Fig.16 This is a schematic diagram of the installation position of the supplementary fins.

[0050] In the figure: box body 1; unit cavity 101; reinforcing rib 102; reinforcing rib 103; positioning column 104; overlapping step 105; lower raised rib 106; avoidance groove 107; cover plate 2; upper groove 201; positioning hole 202; upper raised rib 203; insertion slit 204; connecting groove 205; phase change layer 3; phase change block 301; upper tank body 302; lower tank body 303; stirring head 4; supplementary fin 5; closed cavity 501; thin-walled sheet 502. DETAILED DESCRIPTION

[0051] Embodiment 1:

[0052] like Figure 1-4 In the invention, a multi-compartment phase change cold plate is provided, including a box body 1 and a cover plate 2. A trough structure is provided in the box body 1. The inner wall of the trough structure is provided with an overlapping step 105. A plurality of reinforcing ribs 102 are provided at the bottom of the trough structure. The reinforcing ribs 102 divide the trough structure into a plurality of unit cavities 101. A reinforcing rib 103 is provided at the upper end of the reinforcing rib 102. A plurality of upper grooves 201 are provided on the lower end surface of the cover plate 2. The edge of the cover plate 2 is placed on the overlapping step 105. The reinforcing rib 103 is inserted into the upper groove 201. Phase change material is provided in each unit cavity 101.

[0053] The box body 1 and the cover plate 2 can be made of metal material with good thermal conductivity.

[0054] Due to the presence of the upper groove 201, the thickness of the cover plate 2 becomes thinner here. When performing rotational friction welding, the stirring head 4 rubs against the upper surface of the cover plate 2 to generate high temperature so that the material here melts and becomes liquid. Since the stirring head 4 will feed to a certain depth, the material at the bottom of the stirring head 4 and the upper end of the reinforcing rib 103 participate in the friction welding process, and the molten material contacts the upper end of the reinforcing rib 103, and the stirring head 4 is equivalent to penetrating the cover plate 2. The stirring head 4 moves along the length direction of the reinforcing rib 103, and the material behind cools and solidifies so that the reinforcing rib 103 and the cover plate 2 are connected as one.

[0055] The thickness of the reinforcing rib 102 is greater than the diameter of the stirring head 4. Since the diameter of the stirring head 4 is small, only local high temperature will be generated during friction. The high temperature area is distributed near the upper end and both sides of the reinforcing rib 103, and less heat spreads into the unit cavity 101. Therefore, the phase change material will not vaporize and escape due to excessive temperature, and the overall loss of the phase change material is small.

[0056] If the phase change layer 3 is filled before the box body 1 and the cover plate 2 are assembled, the phase change layer 3 needs to be divided into multiple phase change blocks 301 according to the size of the unit cavity 101, and each phase change block 301 is filled into each unit cavity 101. One side of the phase change cold plate contacts the heat-generating chip and conducts the heat to the phase change block 301 in the unit cavity 101. Since the temperature of the phase change block 301 does not change during the phase change, it can prevent the chip from rising sharply for a period of time. Cooling measures are taken on the other side of the phase change cold plate to quickly dissipate the heat.

[0057] The end surface of the cover plate 2 is flush with the end surface of the box body 1. After the friction welding is completed, the phase change cold plate is placed on a grinder for flat grinding to remove the welding lines left on the surface of the box body 1 and the cover plate 2.

[0058] In a preferred solution, at least two positioning holes 202 are provided on the cover plate 2 , and at least two positioning posts 104 are provided on the reinforcing rib 102 , and the positioning posts 104 are inserted into the positioning holes 202 .

[0059] The positioning column 104 can be used to make the gap between the outer edge of the cover plate 2 and the box body 1 uniform. The joint between the outer edge of the cover plate 2 and the box body 1 and the joint between the positioning column 104 and the positioning hole 202 are also closed by friction welding using the stirring head 4.

[0060] In a preferred embodiment, a plurality of reinforcing ribs 102 are arranged transversely and longitudinally to form a grid structure, and the positioning posts 104 are disposed at intersection nodes of the grid structure.

[0061] like Figure 5-7 The lower end surface of the cover plate 2 is also provided with a plurality of upper raised ribs 203 , and the unit cavity 101 is provided with a plurality of lower raised ribs 106 .

[0062] The lower raised rib 106 and the upper raised rib 203 can be used as reinforcing ribs of the box body 1 and the cover plate 2 to improve the structural strength and prevent deformation. At the same time, they can increase the contact area with the phase change material and improve the thermal conductivity.

[0063] In a preferred embodiment, the height of the lower raised rib 106 and the upper raised rib 203 is lower than the height of the reinforcing rib 102 .

[0064] If the sum of the heights of the lower raised rib 106 and the upper raised rib 203 is equal to the height of the reinforcing rib 102, it means that the phase change block 301 needs to be further divided into small blocks and placed in smaller unit compartments, resulting in unnecessary installation workload and the processing technology will become more complicated.

[0065] like Figure 11-12 A supplementary fin 5 is further provided between the box body 1 and the cover plate 2 in each unit cavity 101, and two ends of the supplementary fin 5 are respectively connected to the box body 1 and the cover plate 2.

[0066] The supplementary fins 5 are embedded in the phase change block 301 to increase the contact surface between the box body 1 and the cover plate 2 and the phase change material, thereby improving the heat conduction efficiency.

[0067] like Fig.13 An avoidance groove 107 is provided on the lower raised rib 106 at the bottom end of the unit cavity 101, and one end of the supplementary fin 5 is inserted into the avoidance groove 107. A through insertion slot 204 is provided on the cover plate 2 near each unit cavity 101, and the other end of the supplementary fin 5 is inserted into the insertion slot 204.

[0068] The phase change material can be preheated into a liquid state. When the supplementary fins 5 are inserted and installed, the liquid level rises and squeezes out the air in each area of ​​the cold plate, so that the liquid phase change material fully contacts each metal surface, thereby increasing the contact area and improving the thermal conductivity.

[0069] Since the volume change rate of the phase change material is generally less than 10% when the phase change occurs, which is not too large, the usual practice is to increase the wall thickness of the plate and rely on the strength of the material itself to reduce the deformation caused by the volume change. Or the side wall strength is strengthened by structural optimization, such as the above-mentioned reinforcing ribs 102, lower raised ribs 106 and upper raised ribs 203. However, whether the wall thickness is thickened or the reinforcing ribs are added, the total amount of phase change material will be reduced, and because there are many such structures, the filling space of the phase change material is actually reduced a lot, and the total mass and volume of the phase change cold plate are both large.

[0070] In a preferred embodiment, a closed cavity 501 is provided inside the supplementary fin 5 , the outer wall of the closed cavity 501 is a deformable thin-walled sheet 502 , and the closed cavity 501 is filled with a compressible gas.

[0071] The long thin-walled sheet 502 can be cut and welded into a ring shape at the first end. The upper and lower ends of the ring-shaped thin-walled sheet 502 are welded and sealed with the same material and thickness as the thin-walled sheet 502 to form a supplementary fin 5 with a closed cavity 501. Since the thin-walled sheet 502 is thin and has a certain elastic deformation ability, the air is sealed in the closed cavity 501 and can be compressed in volume. When the phase change material in the unit cavity 101 undergoes a phase change, if the volume increases, the phase change material squeezes the thin-walled sheet 502, causing the thin-walled sheet 502 to be concave toward the closed cavity 501; if the volume decreases, the air in the closed cavity 501 squeezes the thin-walled sheet 502 outward, causing the thin-walled sheet 502 to deform outward. In this way, the supplementary fins 5 can adapt to the volume change during phase change, sacrificing the supplementary fins 5 in exchange for the good stress condition of other wall panels, the wall thickness of the box body 1 and the cover plate 2 can be appropriately reduced, and the height and thickness of each reinforcing rib can also be appropriately reduced, so that the total volume and total mass of the cold plate are reduced, and the proportion of phase change material is increased. In addition, it is ensured that the phase change material can contact the inner wall of the cavity to the greatest extent regardless of the solid or liquid state, thereby improving the thermal conductivity.

[0072] In a preferred solution, an upper slot body 302 and a lower slot body 303 are respectively provided on both sides of each phase change block 301 , the upper raised rib 203 is embedded in the upper slot body 302 , and the lower raised rib 106 is embedded in the lower slot body 303 .

[0073] The plurality of lower raised ribs 106 and upper raised ribs 203 are interwoven to form a grid structure, and the corresponding upper trough body 302 and lower trough body 303 are grid structures of corresponding sizes, with a more regular shape and easy processing.

[0074] In the preferred embodiment,

[0075] Processing the box body 1, the cover plate 2 and the supplementary fins 5. In small batch production, the box body 1 and the cover plate 2 can be processed by CNC milling. In large batch production, the box body 1 and the cover plate 2 can be formed by a mold first, and then the surface can be milled by CNC to improve production efficiency;

[0076] Buckle the box body 1 and the cover plate 2 together;

[0077] The small reinforcement rib 103 and the seam between the edge of the cover plate 2 and the box body 1 are welded by penetrating friction welding;

[0078] Heating a solid phase change material to liquefy it;

[0079] Adjust the cover plate 2 to be level;

[0080] Fill the liquefied phase change material into each unit cavity 101 through each slot 204, and make the liquid level flush with the lower side of the cover plate 2. In order to prevent the phase change material from re-solidifying, this operation can be performed quickly in a constant temperature box;

[0081] Insert the supplementary fin 5 through the insertion slot 204 and make the lower end abut against the bottom end of the unit cavity 101, and wipe off the phase change material overflowing from the insertion slot 204. Fig.14 The upper raised rib 203 is provided with a connecting groove 205 to connect adjacent compartment areas to avoid residual air;

[0082] In order to improve the structural strength of the supplementary fin 5, the supplementary fin 5 can be made into a wave shape or a broken line shape as a whole, such as Fig.15 , replace the stirring head with a larger diameter, and use rotary friction welding to weld the joint between the supplementary fin 5 and the insert seam 204, and a single pass can weld two seams at the same time;

[0083] After the welding position has cooled, place the cold plate as a whole on the grinder and grind the outer side surface to eliminate the friction welding marks.

[0084] Embodiment 2:

[0085] In this embodiment, the material of the welded part is aluminum alloy 6063-T6.

[0086] like Figure 1 As shown, the thickness of the cold plate cover is 2mm, the large rib width of the cold plate shell is 3mm, the overlap step width is 1.5mm, the overlap step is 2.0mm from the upper surface, the small rib width is 1.0mm, and the height is 0.6mm. The stirring needle of the selected stirring head has a length of 2mm, a needle tip diameter of 2.0mm, a needle root diameter of 2.8mm, a shoulder diameter of 5.6mm, and a sinking depth of 0.1mm. The stirring head speed during penetration welding is 2300 rpm, and the welding speed is 120 mm / min.

[0087] After welding according to the above steps, a phase change cold plate A is obtained.

[0088] like Figure 8 As shown, the external structure and size of this cold plate are the same as those of phase change cold plate A, except that there are no large ribs and small ribs, and the model parameters of the phase change material are the same as those of phase change cold plate A. The model of the stirring head, the rotation speed, and the welding speed are the same as those of phase change cold plate A. Only butt welding is performed without penetration welding to obtain phase change cold plate B.

[0089] like Fig. 9 As shown, from top to bottom, the structure consists of 8 cover plates, 8 phase change materials, and 1 cold plate shell. The model parameters of the phase change materials are the same as those of the phase change cold plate A. The stirring head model, rotation speed, and welding speed are the same as those of the phase change cold plate A. Only butt welding is performed without penetration welding to obtain the phase change cold plate C.

[0090] In order to compare the thermal performance of the phase change cold plates with three welding methods, a simulated heat source test was carried out on the phase change cold plates A, B, and C, and the working conditions of the three cold plates at room temperature were compared: the time required for the simulated heat source power of 30W to work at 100℃.

[0091] The test steps are as follows: a single simulated heat source, a ceramic heating element, heat consumption of 30W, at room temperature, after setting the required power of the simulated power supply, turn on the power supply and start timing; record the temperature every 1 second until the temperature of the ceramic thermocouple reaches 100℃ and then stop; compare the curve of 25℃-100℃ temperature change with time. The input power set for the cold plate simulated heat consumption (ceramic heating element) is shown in the following table.

[0092]

[0093] The test results are as follows Fig.10 As shown, the time required for the simulated heat source of phase change cold plate A to reach 100°C is 2455 seconds, the time required for the simulated heat source of phase change cold plate B to reach 100°C is 2719 seconds, and the time required for the simulated heat source of phase change cold plate C to reach 100°C is 2287 seconds. The time required for the simulated heat source of phase change cold plate B to reach 100°C is the longest, indicating that B has the largest heat storage capacity, which is related to the weight of the filled phase change material. However, after the test, bulging and deformation occurred on the surface of cold plate B, while the structural temperature of cold plates A and C was the same, and the surface was not deformed. In terms of comprehensive structural strength and heat storage performance, the performance of phase change cold plate A is the best. It shows that a penetrating friction stir welding method for phase change cold plate provided by the present invention can effectively solve the problem of insufficient welding strength of phase change cold plate, while ensuring the maximum filling amount of phase change material.

[0094] Embodiment 3:

[0095] In this embodiment, the material of the welded part is aluminum alloy 2A12.

[0096] like Figure 5 As shown, the maximum thickness of the cold plate cover is 3.8mm, the large rib width of the cold plate shell is 4mm, the overlap step width is 1.5mm, the overlap step is 3.8mm from the upper surface, the small rib width is 1.0mm, and the height is 2.5mm. The stirring needle of the selected stirring head is 2mm long, the needle tip diameter is 3.0mm, the needle root diameter is 4mm, the shaft shoulder diameter is 8mm, and the sinking is 0.1mm. The stirring head speed during penetration welding is 2200 rpm and the welding speed is 100 mm / min.

[0097] The phase change cold plate was subjected to temperature cycle test and random vibration test. The test steps were as follows: the cold plate was placed in the temperature cycle box provided by Wuhan Changyingtong Thermal Control Technology Co., Ltd., the high temperature setting value was +120℃, and the temperature was kept warm for 2 hours, the low temperature setting value was -45℃, and the temperature was kept warm for 2 hours. The temperature change rate during the heating and cooling process was 10℃ / min. A total of 10 hot and cold temperature cycles were performed, and the appearance after the cycle was observed. The cold plate after the cycle was then placed on the vibration table provided by Wuhan Changyingtong Optoelectronic Technology Co., Ltd. for random vibration test, and vibration was performed in three directions, each direction lasting 5 minutes, and the root mean square acceleration value was 6.06G.

[0098] After the test, the cold plate has a good appearance without bulging, deformation or cracking, which shows that this method can effectively solve the problem of insufficient welding strength of phase change cold plate.

[0099] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A phase change cold plate based on penetrating friction welding, characterized by: The invention comprises a box body (1), a cover plate (2) and a phase change layer plate (3); a sink structure is provided in the box body (1); an inner wall of the sink structure is provided with an overlapping step (105); a plurality of reinforcing ribs (102) are provided at the bottom of the sink structure; the reinforcing ribs (102) divide the sink structure into a plurality of unit cavities (101); the phase change layer plate (3) comprises a plurality of phase change blocks (301); each phase change block (301) is arranged in each unit cavity (101); a small reinforcing rib (103) is provided at the upper end of the large reinforcing rib (102); a plurality of upper grooves (201) are provided on the lower end surface of the cover plate (2); the edge of the cover plate (2) is placed on the overlapping step (105); and the small reinforcing ribs (103) are inserted into the upper grooves (201).

2. The phase change cold plate based on penetrating friction welding according to claim 1 is characterized in that: At least two positioning holes (202) are provided on the cover plate (2), and at least two positioning columns (104) are provided on the reinforcing rib (102), wherein the positioning columns (104) are inserted into the positioning holes (202).

3. The phase change cold plate based on penetrating friction welding according to claim 2 is characterized in that: A plurality of reinforcing ribs (102) are arranged in a transverse and longitudinal direction to form a grid-like structure, and positioning columns (104) are arranged at intersection nodes of the grid-like structure.

4. The phase change cold plate based on penetrating friction welding according to claim 1 is characterized in that: The lower end surface of the cover plate (2) is also provided with a plurality of upper raised ribs (203), a plurality of lower raised ribs (106) are provided in the unit cavity (101), and each phase change block (301) is provided with an upper slot body (302) and a lower slot body (303) on the upper and lower sides respectively, the upper raised ribs (203) are embedded in the upper slot body (302), and the lower raised ribs (106) are embedded in the lower slot body (303).

5. The phase change cold plate based on penetrating friction welding according to claim 4 is characterized in that: The height of the lower raised rib (106) and the upper raised rib (203) is lower than the height of the reinforcing rib (102).

6. The phase change cold plate based on penetrating friction welding according to claim 1 is characterized in that: The end surface of the cover plate (2) is flush with the end surface of the box body (1).

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