Flat plate pulse heat pipe special for photovoltaic cell waste heat utilization and manufacturing method

Abstract

The invention relates to a flat plate pulse heat pipe special for photovoltaic cell waste heat utilization and a manufacturing method. An aluminum flat plate half-pulse heat pipe bottom plate and an aluminum flat plate half-pulse heat pipe end plate are integrally arranged on the back face of a photovoltaic cell module. The aluminum flat plate half-pulse heat pipe bottom plate and the aluminum flat plate half-pulse heat pipe end plate which are integrated and a battery module protection film arranged on the back face of the photovoltaic battery module jointly form a complete flat plate half-pulse heat pipe, and the aluminum flat plate half-pulse heat pipe end plate is arranged at the cold end of the aluminum flat plate half-pulse heat pipe bottom plate; and the refrigerant heat exchanger is arranged on the aluminum flat plate semi-pulse heat pipe end plate. Compared with a conventional pulse heat pipe, the pulse heat pipe has the cost advantage and is high in waste heat absorption efficiency, and meanwhile the problem that metal aluminum is incompatible with glass thermal stress is solved.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic cells, and more specifically to a flat pulse heat pipe dedicated to the waste heat utilization of photovoltaic cells and a manufacturing method thereof. Background Art

[0002] When a photovoltaic cell is in use, most of the input solar irradiance energy is absorbed by the photovoltaic cell except for a small part that is reflected. And a part of it is converted into electrical energy, while the remaining part is converted into heat energy. This heat energy will cause the temperature of the photovoltaic cell panel to rise. The increase in the temperature of the photovoltaic cell panel will reduce the battery efficiency, and further cause the photovoltaic cell to generate more heat, thus forming a vicious cycle. At present, most photovoltaic cells mainly rely on the blowing of ambient wind for heat dissipation to achieve heat balance, but the problem of reduced photovoltaic cell efficiency still exists. Therefore, the active heat dissipation problem of photovoltaic cells has been put on the research and development agenda. At present, using a water-cooled plate formed by water-cooled pipes in close contact with the photovoltaic cell panel is a common active heat dissipation method, but this method has disadvantages such as large contact thermal resistance. It requires a temperature gradient to transfer heat to water and is not easy to reduce the photovoltaic panel to an ideal operating temperature.

[0003] In addition, this heat load mode of photovoltaic cells is also a challenge to traditional flat pulse heat pipes. At present, when many publicly disclosed patents use flat heat pipes to absorb and transfer the waste heat emitted by photovoltaic cells, few people specifically analyze the special heat load characteristics of the waste heat of photovoltaic cell panels. Only a few researchers have found that there are certain problems in using the existing flat heat pipe structure as a waste heat utilization device for photovoltaic cell panels. For example, the authorized invention patent with the patent number 201410636304.7 and the name "A solar photovoltaic-thermal integrated energy conversion component" mentions in the background art that "now the condensate of ordinary heat pipes directly flows to the bottom of the pulse heat pipe under the action of gravity, making the temperature of the pulse heat pipe uneven, with poor heat transfer effect and low heat flux", but this patent only proposes a solution for the external phenomenon of "uneven heat pipe temperature, poor heat transfer effect and low heat flux", and this solution is based on a new concept "liquid distribution sheet" developed by this patent. Its purpose is to use the liquid distribution sheet to guide the liquid flowing back from the cold end of each cavity of the pulse heat pipe to the heated section of the pulse heat pipe. There are a total of four types of liquid distribution sheets claimed in this patent, which are rolled up in a circulating series form and placed in each cavity of the flat pulse heat pipe. At the same time, this patent also claims that "capillary liquid absorption layers are evenly distributed on the inner side of the heated surface of the flat pulse heat pipe, and the material of the capillary liquid absorption layer is metal suction wire, fiberglass mesh, or powder metal sintered layer".

[0004] However, because the heat generated per unit area of photovoltaic panels is a low-grade heat source, first of all, from a practical and economic perspective, it is unlikely that actual products will use copper sintered powder to form a capillary layer to prepare flat-plate pulse heat pipes, which is expensive. Actual products can usually only adopt a simple structure similar to a horizontal array of gravity heat pipes. As for sintering only on the inner surface of the pulse heat pipe corresponding to the heated surface, it is not only uneconomical, but also easy to cause the flat heat pipe to deform due to uneven stress during heating and cooling, so that it cannot fit well against the photovoltaic panels, and thus cannot efficiently absorb the waste heat of the photovoltaic panels. In addition, it is difficult to evenly place items such as wire mesh and liquid cloth sheets into the narrow and long flat heat pipe grooves, and the heat transfer consistency is not easy to guarantee.

[0005] Secondly, the materials used in photovoltaic cells must also be carefully considered. Aluminum or aluminum alloy has good thermal conductivity, is lightweight, and has a price per unit volume far lower than copper. Therefore, it is recognized as one of the best choices for flat-plate pulse heat pipes. Putting other metals into flat-plate heat pipes without specifying the type will cause problems. This is because different metals in contact will cause contact potential due to different chemical activities. When pure water is used as a phase change heat transfer medium, due to the natural presence of free ions in water, heat pipes need to have a service life of more than ten years. If this time is not waited for, electrochemical corrosion will occur, shortening the service life of the flat-plate heat pipe. If glass fiber mesh is used, there will also be problems. Without hydrophilic polar molecular grafting treatment on its surface, it is difficult to achieve the wettability required by capillary force. The thermal conductivity of glass fiber is much lower than that of metal, which will reduce the start-up speed of thermal phase change and thus affect the performance of the heat pipe.

[0006] Furthermore, the reason waste heat from photovoltaic panels presents a unique heat load for heat pipes is that the flat-plate heat pipes are tilted. While the angle isn't very sharp, it's certainly not vertical. Generally, it's assumed that the hot end is at the bottom and the cold end is at the top, meeting the requirements for gravity pipes. However, a closer look at a single square centimeter reveals that because heat is generated on the top side of the photovoltaic heat pipes, the returning liquid medium inevitably flows on the back side of the flat-plate heat pipes, creating a localized situation where the hot end is at the top and the cold end is at the bottom, which doesn't meet the requirements for gravity pipes. This is one of the reasons why many flat-plate heat pipes fail for similar heat loads.

[0007] After the Japanese invented the pulsating heat pipe, as a deformation of the heat pipe, many thin-diameter and recyclable pipes are arranged in a serpentine shape on a plane. After the heat pipe starts, due to the very thin pipe diameter, after the saturated water vapor condenses and releases heat during phase change at the cold end, it will become liquid and fill the pipe diameter, thus forming a structure similar to a liquid slug column. The saturated steam in the subsequent pipes will then push the liquid slug column to move in one direction. This design does not require a capillary structure, and the entire system does not require the hot end to be below and the cold end to be above, which facilitates some special heat transfer requirements. However, since the diameter at the turning point of the serpentine pipe in this structure is relatively large, it means it is a very long pipe. Not only does it take a long time to coil such a long pipe, but there are also difficulties in ensuring that the pipeline can fit flat and fully on the battery plane. If the fit is uneven, the heat absorption efficiency will be reduced.

[0008] Finally, in the practice of direct cooling waste heat utilization in the refrigerant evaporation chamber of photovoltaic cells, there is also a problem of incompatibility between the thermal stress of the aluminum evaporation chamber and the glass, which will cause the glass panel to break. As a solution to the above problem, some products use an organic transparent plate with a thermal expansion coefficient close to that of aluminum alloy to replace the glass substrate to prevent the glass substrate from breaking. However, the hardness of the organic transparent plate is not enough, and it will soon be scratched by sand and lose its transparency, and it will also shorten the life of the photovoltaic cell. At the same time, this application example also proves that the silicon wafer photovoltaic cell layer in the photovoltaic cell module can allow the thermal expansion stress of the aluminum flat evaporation chamber. What needs to be solved is the problem of incompatibility between the thermal stress of aluminum and the glass substrate. Summary of the Invention

[0009] The purpose of the present invention is to provide a flat pulsating heat pipe dedicated to waste heat utilization of photovoltaic cells and its manufacturing method, which has significant cost advantages compared with conventional pulsating heat pipes, high waste heat absorption efficiency, and at the same time solves the problem of incompatibility between the thermal stress of metal aluminum and glass.

[0010] The purpose of the present invention is achieved through the following technical solutions:

[0011] A flat-plate pulsating heat pipe dedicated to the waste heat utilization of photovoltaic cells, comprising an aluminum flat-plate semi-pulsating heat pipe bottom plate, an aluminum flat-plate semi-pulsating heat pipe end plate, and a refrigerant heat exchanger. The aluminum flat-plate semi-pulsating heat pipe bottom plate is arranged on the back of the photovoltaic cell module, and there is glass on the other side of the photovoltaic cell module. On the side of the aluminum flat-plate semi-pulsating heat pipe bottom plate away from the photovoltaic cell module, there are straight cavity protrusions and U-shaped cavity protrusions, and the hot ends of any two adjacent straight cavity protrusions are connected through the corresponding U-shaped cavity protrusions. The straight cavity protrusions and U-shaped cavity protrusions, together with the battery module protective film arranged on the back of the photovoltaic cell module, form a closed pulsating heat pipe duct cavity. The aluminum flat-plate semi-pulsating heat pipe end plate is arranged at the cold end of the aluminum flat-plate semi-pulsating heat pipe bottom plate, and the refrigerant heat exchanger is arranged on the aluminum flat-plate semi-pulsating heat pipe end plate. On the bottom side of the aluminum flat-plate semi-pulsating heat pipe end plate, there are straight grooves, U-shaped grooves, and circulation grooves. One end of the straight groove is provided with an interface groove that buckles on the end of the corresponding straight cavity protrusion, and the other end is connected to the adjacent straight groove through the corresponding U-shaped groove. The circulation grooves are arranged outside each straight groove, and the input end and output end of the circulation groove are both provided with interface grooves that respectively buckle on the end of the outermost corresponding straight cavity protrusion. The aluminum flat-plate semi-pulsating heat pipe bottom plate, the aluminum flat-plate semi-pulsating heat pipe end plate, the photovoltaic cell module, and the glass are encapsulated and fixed by aluminum alloy edge sealing.

[0012] The aluminum flat-plate semi-pulsating heat pipe end plate includes a end plate main body, and there is an end plate screw on the end plate main body. There is a connecting plate outside the refrigerant heat exchanger, and the end plate screw passes through the connecting plate and is threadedly connected and fastened with a nut.

[0013] On one side of the end plate main body, there is a perfusion pipe, and on the other side, there is a transition groove, and the perfusion pipe communicates with the transition groove, and the transition groove communicates with the circulation groove.

[0014] One end of the refrigerant heat exchanger is provided with a refrigerant medium inlet pipe, and the other end is provided with a refrigerant medium outlet pipe.

[0015] The aluminum flat-plate semi-pulsating heat pipe bottom plate is formed by pressing a whole plate to form the straight cavity protrusions and U-shaped cavity protrusions.

[0016] The photovoltaic cell module includes a photovoltaic cell group layer, and there is a polyester film on one side of the photovoltaic cell group layer and a battery module protective film on the other side. There is glass on the side of the polyester film away from the photovoltaic cell group layer. Both between the photovoltaic cell group layer and the polyester film and between the photovoltaic cell group layer and the battery module protective film are bonded by hot melt adhesive.

[0017] The aluminum alloy edge sealing includes a frame, and a first support plate, a second support plate, and a third support plate are sequentially arranged inside the frame. The edge of the aluminum flat plate half-pulse heat pipe bottom plate is provided with a bottom plate side plate without a straight cavity protrusion. The outside of the end plate body of the aluminum flat plate half-pulse heat pipe end plate is provided with an end plate side plate. The edge of the glass, the edge of the photovoltaic cell module, the bottom plate side plate, and the end plate side plate are sequentially arranged between the first support plate and the second support plate, and silicone glue is provided between the first support plate and the glass and between the second support plate and the end plate side plate.

[0018] The displacement of the end plate body is limited by the second support plate of the aluminum alloy frame. An end plate screw is provided on the end plate body, and the third support plate is arranged above the end plate screw. The refrigerant heat exchanger passes through and is exposed between each third support plate.

[0019] A connecting plate is provided between the second support plate and the third support plate of the aluminum alloy frame, and the frame, the second support plate, the third support plate, and the connecting plate enclose a hollow cavity.

[0020] A manufacturing method of a flat plate pulse heat pipe dedicated to the waste heat utilization of photovoltaic cells according to the above includes the following steps:

[0021] Step 1: Place a polyester film on the glass;

[0022] Step 2: Place a hot melt adhesive film A on the polyester film;

[0023] Step 3: Fabricate a photovoltaic cell group layer on the hot melt adhesive film A;

[0024] Step 4: Place a hot melt adhesive film B on the photovoltaic cell group layer;

[0025] Step 5: Place a protective insulating film on the hot melt adhesive film B to form the battery module protective film;

[0026] Step 6: Use a hot pressing process to melt the hot melt adhesive film A and the hot melt adhesive film B, and bond the glass, the polyester film, the photovoltaic cell group layer, and the battery module protective film together, where the polyester film, the photovoltaic cell group layer, and the battery module protective film form a photovoltaic cell module;

[0027] Step 7: Heat the straight cavity protrusion openings of the aluminum flat plate half-pulse heat pipe bottom plate and the aluminum flat plate half-pulse heat pipe end plate, which are welded and connected together, with the openings facing upward, and the heating temperature is set at a temperature above the melting point of the hot melt adhesive;

[0028] Step 8: Apply liquid hot melt adhesive to the integrated aluminum flat plate half-pulse heat pipe bottom plate and aluminum flat plate half-pulse heat pipe end plate;

[0029] Step Nine: Use the hot pressing process to press the integrated aluminum flat semi-pulse heat pipe bottom plate and the aluminum flat semi-pulse heat pipe end plate onto the battery module protective film pressed on the back of the photovoltaic cell module.

[0030] Step Ten: Fix the refrigerant heat exchanger to the aluminum flat semi-pulse heat pipe end plate;

[0031] Step Eleven: Use aluminum alloy edge sealing to fix the aluminum integrated flat semi-pulse heat pipe bottom plate, the aluminum semi-pulse heat pipe end plate, the photovoltaic cell module, and the glass package.

[0032] The advantages and positive effects of the present invention are as follows:

[0033] 1. The pulse heat pipe of the present invention is only half of the conventional complete circular pulse heat pipe. At the same time, the aluminum flat semi-pulse heat pipe bottom plate and the aluminum flat semi-pulse heat pipe end plate are both integrally processed and formed. Therefore, it has significant cost advantages. Moreover, the operating temperature of the flat pulse heat pipe proposed by the present invention is much lower than the boiling point of the medium. In fact, it has been working under negative pressure for a long time. The absolute pressure of saturated steam at 80°C is less than 0.5 atmospheres. In the atmospheric environment, the pulse heat pipe chamber is always under negative pressure. Not only the material requirements are not high, but the negative pressure packaging is also relatively simple, which can further reduce costs.

[0034] 2. The aluminum flat semi-pulse heat pipe bottom plate of the present invention is integrally pressed from a whole thin plate (made of aluminum or aluminum alloy) to form a straight cavity protrusion and a U-shaped cavity protrusion. The side in contact with the battery module protective film can fully ensure a flat fit. At the same time, the openings of the straight cavity protrusion and the U-shaped cavity protrusion face the photovoltaic cell module. In this way, the heat generating surface of the photovoltaic cell module directly serves as a part of the heat pipe, and a better heat absorption effect can be achieved.

[0035] 3. The present invention uses a pulse heat pipe method without a capillary structure and separately sets up a set of refrigerant heat exchangers. The refrigerant heat exchanger is combined with the aluminum flat semi-pulse heat pipe end plate to achieve forced refrigeration at the cold end, improve the temperature difference between the cold end and the hot end, and accelerate the flow rate of the two-phase flow. At the same time, the present invention uses the pulse heat pipes (i.e., the straight cavity protrusion and the U-shaped cavity protrusion) evenly distributed on the back of the photovoltaic cell module to concentrate the waste heat of the photovoltaic cell into a small area at the upper cold end (i.e., the straight groove and the U-shaped groove), and then the refrigerant heat exchanger performs centralized heat exchange, which improves the heat collection and absorption efficiency.

[0036] 4. The present invention uses a polyester film instead of glass in the photovoltaic cell module. The glass is not fixed to the photovoltaic cell module with hot melt adhesive, that is, there is no direct connection between the photovoltaic cell module and the glass, while the other planar materials participating in the photovoltaic cell module are bonded together with hot melt adhesive. In this way, the thermal strains of each layer of materials are basically compatible, and the thermal stress caused by the flat pulse heat pipe on the back of the photovoltaic cell module is avoided from being transmitted to the glass.

[0037] 5. In the present invention, the aluminum flat plate semi-pulse heat pipe bottom plate, the aluminum flat plate semi-pulse heat pipe end plate, the photovoltaic cell module and the glass are encapsulated and fixed by using the same set of aluminum alloy edge seals. The glass edge, the photovoltaic cell module edge, the bottom plate side plate and the end plate side plate are arranged between the first support plate and the second support plate of the aluminum alloy edge seal. Silicone glue is provided between the first support plate and the glass and between the second support plate and the end plate side plate to achieve sealing. After curing, the silicone glue still remains highly flexible, which can eliminate the differences in thermal stress of various bonded materials. At the same time, the thermal strain of the glass is different from other materials, and it can eliminate stress by generating a small displacement through sliding contact with the polyester film. The flexibility of the silicone glue just provides this possibility while ensuring the integrity of the seal.

[0038] 6. In the present invention, the aluminum flat plate semi-pulse heat pipe bottom plate, the aluminum flat plate semi-pulse heat pipe end plate, the photovoltaic cell module and the glass are encapsulated and fixed by using the same set of aluminum alloy edge seals, which not only saves material costs and working hours, but also has a simple and compact structure and is convenient for installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a schematic structural diagram of the present invention,

[0040] Figure 2 is Figure 1 an enlarged view of part A in

[0041] Figure 3 is Figure 1 an enlarged view of part B in

[0042] Figure 4 is Figure 1 a schematic structural diagram of the present invention after removing the refrigerant heat exchanger in

[0043] Figure 5 is Figure 4 an enlarged view of part C in

[0044] Figure 6 is Figure 4 a schematic structural diagram of the aluminum flat plate semi-pulse heat pipe end plate in

[0045] Figure 7 is Figure 6 an enlarged view of part D in

[0046] Figure 8 is Figure 6 a schematic structural diagram of the other side of the aluminum flat plate semi-pulse heat pipe end plate in

[0047] Figure 9 is Figure 8 an enlarged view of part E in

[0048] Figure 10 is Figure 8Enlarged view at K in

[0049] Figure 11 is Figure 4 Schematic structural diagram of the aluminum flat plate semi-pulse heat pipe bottom plate in

[0050] Figure 12 is Figure 11 Enlarged view at H in

[0051] Figure 13 is Figure 11 Enlarged view at I in

[0052] Figure 14 is Figure 11 Enlarged view at G in

[0053] Figure 15 is Figure 11 Enlarged view at F in

[0054] Figure 16 is Figure 1 Schematic back view of the present invention in

[0055] Figure 17 is Figure 16 M-M view in

[0056] Figure 18 is Figure 17 Enlarged view at P in

[0057] Among them, 1 is the aluminum flat plate semi-pulse heat pipe bottom plate, 101 is the straight cavity protrusion, 102 is the U-shaped cavity protrusion, 103 is the bottom plate side plate, 104 is the first electrical interface hole, 105 is the second electrical interface hole, 106 is the pulse heat pipe pipe cavity, 2 is the aluminum flat plate semi-pulse heat pipe end plate, 201 is the end plate screw, 202 is the end plate main body, 203 is the interface groove, 204 is the perfusion pipe, 205 is the end plate side plate, 206 is the straight groove, 207 is the U-shaped groove, 208 is the circulation groove, 209 is the transition groove, 3 is the refrigerant heat exchanger, 301 is the refrigerant medium inlet pipe, 302 is the refrigerant medium outlet pipe, 303 is the nut, 304 is the connecting plate, 4 is the glass, 5 is the photovoltaic cell module, 501 is the battery module protective film, 6 is the aluminum alloy edge seal, 601 is the first support plate, 602 is the second support plate, 603 is the third support plate, 604 is the hollow pipe cavity, 605 is the frame, 606 is the connecting plate. Detailed implementation manners

[0058] The present invention will be further described in detail below with reference to the accompanying drawings.

[0059] As Figures 1 to 18 shown, the present invention includes an aluminum flat plate semi-pulse heat pipe bottom plate 1, an aluminum flat plate semi-pulse heat pipe end plate 2 and a refrigerant heat exchanger 3, among which as Figure 3 andFigures 12 to 13 As shown, the aluminum flat plate semi-pulse heat pipe bottom plate 1 is arranged on the back of the photovoltaic cell module 5, and a straight cavity protrusion 101 and a U-shaped cavity protrusion 102 are arranged on the side of the aluminum flat plate semi-pulse heat pipe bottom plate 1 away from the photovoltaic cell module 5. The hot ends (i.e., the ends away from the refrigerant heat exchanger 3) of any two adjacent straight cavity protrusions 101 are connected through the corresponding U-shaped cavity protrusions 102, as Figure 18 shown, the straight cavity protrusion 101 and the U-shaped cavity protrusion 102 and the battery module protective film 501 arranged on the back of the photovoltaic cell module 5 together form a closed pulse heat pipe duct cavity 106, as Figure 4 shown, the aluminum flat plate semi-pulse heat pipe end plate 2 is arranged at the cold end (i.e., the end close to the refrigerant heat exchanger 3) of the aluminum flat plate semi-pulse heat pipe bottom plate 1, as Figures 1 to 2 shown, the refrigerant heat exchanger 3 is arranged on the side of the aluminum flat plate semi-pulse heat pipe end plate 2 away from the aluminum flat plate semi-pulse heat pipe bottom plate 1, as Figures 8 to 9 shown, a straight groove 206, a U-shaped groove 207 and a circulation groove 208 are arranged on the bottom side of the aluminum flat plate semi-pulse heat pipe end plate 2. One end of the straight groove 206 is provided with an interface groove 203 buckled on the end of the corresponding straight cavity protrusion 101, and the other end is connected to the adjacent straight groove 206 through the corresponding U-shaped groove 207. The circulation groove 208 is arranged outside each straight groove 206, and the input end and the output end of the circulation groove 208 are both provided with interface grooves 203 buckled on the ends of the outermost two straight cavity protrusions 101 respectively. In this embodiment, the aluminum flat plate semi-pulse heat pipe bottom plate 1 and the aluminum flat plate semi-pulse heat pipe end plate 2 are welded into one body and arranged on the back of the photovoltaic cell module 5, and the integrated aluminum flat plate semi-pulse heat pipe bottom plate 1 and the aluminum flat plate semi-pulse heat pipe end plate 2 and the battery module protective film 501 arranged on the back of the photovoltaic cell module 5 together form a complete flat plate pulse heat pipe.

[0060] When the present invention works, the straight groove 206 and the straight cavity protrusion 101 are correspondingly connected to form a serpentine channel. At the same time, the circulation groove 208 is connected to the outermost two straight cavity protrusions 101 to realize the circulating flow of the liquid in the serpentine channel, thereby forming a complete set of serpentine pulse heat pipes. When the photovoltaic cell module 5 works, water or coolant flows in the straight cavity protrusion 101 of the aluminum flat plate semi-pulse heat pipe bottom plate 1 to absorb the heat generated by the photovoltaic cell module 5, and then exchanges heat through the refrigerant heat exchanger 3 in the straight groove 206 of the aluminum flat plate semi-pulse heat pipe end plate 2 to reduce the temperature, and then flows into the straight cavity protrusion 101 again through the circulation groove 208, so as to achieve the purpose of continuous heat exchange through circulating flow. Compared with the prior art, the aluminum flat plate semi-pulse heat pipe bottom plate 1 of the present invention is integrally pressed from a whole thin plate (made of aluminum or aluminum alloy) to form the straight cavity protrusion 101 and the U-shaped cavity protrusion 102, as Figure 18As shown, the side in contact with the battery module protective film 501 can fully ensure smooth fitting, thereby ensuring the heat absorption efficiency. The aluminum flat plate semi-pulse heat pipe end plate 2 of the present invention is processed with the straight groove 206, U-shaped groove 207 and circulation groove 208 on the bottom side, and is buckled on the end of the corresponding straight cavity protrusion 101 by using the interface groove 203 to achieve communication and welded into an integral flat plate pulse semi-heat pipe, as Figure 2 and Figure 5 shown. This can ensure the close fitting of the straight groove 206 and the circulation groove 208 with the corresponding straight cavity protrusion 101, and can ensure sealed communication through the welding connection method.

[0061] In this embodiment, the inner arc surface radius of the pulse heat pipe duct cavity 106 is 3 mm, and the bow chord length is 4.5 mm. It is equivalent to a circular duct with a diameter of 2.6 mm, which meets the diameter selection range of the pulse heat pipe. And since the heating surface of the photovoltaic battery module 5 directly serves as one side of the heat pipe, a better heat absorption effect can be achieved. In addition, the present invention uses a refrigerant or water as the heat absorption medium, which is in the critical state of evaporation and condensation in the thin-diameter pulse heat pipe. The pressure inside the pulse heat pipe duct cavity 106 is the saturated vapor pressure of the medium within the working temperature range. As is well known, the saturated vapor pressure at the boiling point is equal to the local ambient atmospheric pressure. As long as the working or shutdown temperature of the photovoltaic battery module 5 is below the boiling point of the medium, the pressure in the pulse heat pipe cavity must be negative pressure. The pulse heat pipe of a standard photovoltaic battery of about 2.5 square meters is under negative pressure inside the cavity, and the total pressure it receives at 20°C to 85°C is 12.5 to 25 tons. Since the pipe diameter is very small, its wall thickness of 0.5 mm can withstand the pressure. At the same time, since the internal pressure is negative pressure, there is no need to use the welding method to form the pipe.

[0062] After the pulse heat pipe is evacuated, a part of the medium is filled and then sealed. The inside of the cavity is also in the critical state of evaporation and condensation of saturated vapor and liquid medium like a common heat pipe. When the medium is heated at the hot end to generate steam, the steam releases heat and condenses into liquid at the cold end U-shaped pipe. And because the pipe diameter is very small, it quickly condenses into a liquid column and forms a vapor plug. It will not flow back to the hot end along the pipe wall, but will enter the next straight pipe channel along the U-shaped pipe under the push of the subsequent steam and return to the hot end in the form of a liquid column.

[0063] However, the difference between the present invention and the existing commonly used pulsating heat pipes also lies in that: the present invention additionally provides a set of refrigerant heat exchangers 3, and the refrigerant heat exchanger 3 is combined with the aluminum flat semi-pulsating heat pipe end plate 2 to achieve forced refrigeration at the cold end, improving the temperature difference between the cold end and the hot end and accelerating the flow rate of the two-phase flow. In fact, the present invention uses pulsating heat pipes (i.e., straight cavity protrusions 101 and U-shaped cavity protrusions 102) evenly distributed on the back of the photovoltaic cell module 5 to concentrate the waste heat of the photovoltaic cells to a small area at the upper cold end (i.e., straight grooves 206 and U-shaped grooves 207), and then the refrigerant heat exchanger 3 performs centralized heat exchange, which improves the heat collection and heat absorption efficiency.

[0064] As Figures 4 to 7 shown, in this embodiment, the aluminum flat semi-pulsating heat pipe end plate 2 includes an end plate main body 202, and an end plate screw 201 is provided on the end plate main body 202. As Figure 2 shown, a connecting plate 304 is provided on the outside of the refrigerant heat exchanger 3, and the end plate screw 201 passes through the connecting plate 304 and is threadedly connected to a nut 303, thereby realizing the fixation of the refrigerant heat exchanger 3 and the aluminum flat semi-pulsating heat pipe end plate 2. Additionally, as Figures 1 to 2 shown, one end of the refrigerant heat exchanger 3 is provided with a refrigerant medium inlet pipe 301, and the other end is provided with a refrigerant medium outlet pipe 302. The heated refrigerant medium flowing out can be used for heating in other places, thereby realizing the utilization of the waste heat of the photovoltaic cells. The refrigerant heat exchanger 3 is a well-known technology in the art and is a commercially available product.

[0065] As Figures 4 to 10 shown, in this embodiment, a perfusion pipe 204 is provided on one side of the end plate main body 202, and a transition groove 209 is provided on the other side. As Figure 10 shown, the perfusion pipe 204 is communicated with the transition groove 209, the transition groove 209 is communicated with the circulation groove 208, the perfusion pipe 204 is used for evacuating and filling the heat absorption medium, and after filling the medium, the perfusion pipe 204 is sealed by welding or using plugs and other methods.

[0066] As Figure 11 and Figures 14 to 15 shown, in this embodiment, first electrical interface holes 104 are provided on both sides of the middle of the aluminum flat semi-pulsating heat pipe bottom plate 1, and a second electrical interface hole 105 is provided at the middle position of the middle. The first electrical interface holes 104 and the second electrical interface hole 105 are used for the cables for realizing the electrical connection of the photovoltaic cell module 5 to pass through, and the distribution of the straight cavity protrusions 101 is appropriately deformed to avoid the first electrical interface holes 104 and the second electrical interface holes 105.

[0067] Since the present invention uses an aluminum flat-plate semi-pulse heat pipe bottom plate 1 and an aluminum flat-plate semi-pulse heat pipe end plate 2 to realize the waste heat utilization of photovoltaic cells, under the traditional process, it is bound to cause the problem of incompatibility of thermal stress between metallic aluminum and glass 4. The present invention first makes a change in the process, such as Figures 16 to 18 As shown, when manufacturing the photovoltaic cell module 5 of the present invention, the glass 4 is placed at the bottommost layer, and then a layer of polyester film with a high light transmittance is placed on the glass 4. A hot melt adhesive film A with the same size as the glass 4 is placed on the polyester film. Then, a photovoltaic cell group layer is fabricated on the hot melt adhesive film A. Another layer of hot melt adhesive film B is placed on the photovoltaic cell group layer, and a protective insulating film is placed on the hot melt adhesive film B to form the battery module protective film 501 of the present invention. Then, the hot melt adhesive is melted by using a hot pressing process to heat-seal the above-mentioned various layer structures together. The hot pressing process and the photovoltaic cell group layer are both well-known technologies in the art.

[0068] The difference between the present invention and the traditional process is that the present invention uses a polyester film to replace the glass 4 and enter the photovoltaic cell module 5, but the glass 4 does not leave either. It is just not fixed to the photovoltaic cell module 5 with hot melt adhesive, that is, there is no direct connection between the photovoltaic cell module 5 and the glass 4, while the remaining planar materials participating in the photovoltaic cell module 5 are bonded together by hot melt adhesive, so that the thermal strains of the various layer materials are basically compatible.

[0069] After the photovoltaic cell module 5 is manufactured, the present invention heats the straight cavity protrusion 101 of the aluminum flat-plate semi-pulse heat pipe bottom plate 1 with the opening facing upward, and the temperature is about 10 °C above the melting point of the hot melt adhesive. Then, a liquid hot melt adhesive is applied to the aluminum flat-plate semi-pulse heat pipe bottom plate 1 by using a rubber roller. Finally, the straight cavity protrusion 101 of the aluminum flat-plate semi-pulse heat pipe bottom plate 1 with the opening facing downward is pressed onto the battery module protective film 501 on the back of the photovoltaic cell module 5 by using a heated hot pressing process. In this embodiment, the hot melt adhesive is a commercially available product, which can adhere to both metals and organic materials. In addition, the hot pressing process is a well-known technology in the art.

[0070] Secondly, the present invention makes a change in the encapsulation structure, such as Figures 16 to 18 As shown, the present invention uses the same set of aluminum alloy edges 6 to realize the encapsulation and fixation of the aluminum flat-plate semi-pulse heat pipe bottom plate 1, the aluminum flat-plate semi-pulse heat pipe end plate 2, the photovoltaic cell module 5, and the glass 4. Among them, as Figure 18As shown, the aluminum alloy edge seal 6 includes a frame 605, and inside the frame 605, a first support plate 601, a second support plate 602, and a third support plate 603 are sequentially provided. A connecting plate 606 is provided between the second support plate 602 and the third support plate 603, and the frame 605, the second support plate 602, the third support plate 603, and the connecting plate 606 enclose a hollow cavity 604. At the edge of the aluminum flat plate semi-pulse heat pipe bottom plate 1, there is a bottom plate side plate 103 without a straight cavity protrusion 101 arranged. Outside the end plate main body 202 of the aluminum flat plate semi-pulse heat pipe end plate 2, there is an end plate side plate 205. The edges of the glass 4, the photovoltaic cell module 5, the bottom plate side plate 103, and the end plate side plate 205 are arranged between the first support plate 601 and the second support plate 602. Among them, the glass 4 contacts the first support plate 601, the end plate side plate 205 contacts the second support plate 602, and at the same time, the second support plate 602 limits the displacement of the end plate main body 202. The third support plate 603 is arranged above the end plate screw 201 and plays a protective role, and can be fixedly connected to a related bracket, thereby fixing the photovoltaic cell module 5 on the bracket. The refrigerant heat exchanger 3 passes through between each third support plate 603 and is exposed.

[0071] As Figure 18 shown, in this embodiment, silicone glue is provided between the first support plate 601 and the glass 4 and between the second support plate 602 and the end plate side plate 205 to achieve sealing. After the silicone glue cures, it still maintains great flexibility, can effectively maintain the sealing adhesive force, and at the same time eliminates the difference in thermal stress of various materials to be bonded. In addition, the thermal strain of the glass 4 is different from other materials. It can eliminate stress by generating a small displacement through sliding contact with the polyester film, and the flexibility of the silicone glue just provides this possibility and ensures the integrity of the seal.

[0072] The working principle of the present invention is:

[0073] When the present invention works, the straight cavity protrusions 101 on the aluminum flat plate semi-pulse heat pipe bottom plate 1 correspond and communicate with the straight grooves 206 on the aluminum flat plate semi-pulse heat pipe end plate 2 to form a serpentine channel. At the same time, the circulation grooves 208 on the aluminum flat plate semi-pulse heat pipe end plate 2 communicate with the two outermost straight cavity protrusions 101 to realize the circulating flow of the liquid in the channel, thereby forming a complete set of serpentine pulse heat pipes. When the photovoltaic cell module 5 works, water or coolant flows in the straight cavity protrusions 101 of the aluminum flat plate semi-pulse heat pipe bottom plate 1 to absorb the heat generated by the photovoltaic cell module 5, and then exchanges heat through the refrigerant heat exchanger 3 in the straight grooves 206 of the aluminum flat plate semi-pulse heat pipe end plate 2 to reduce the temperature, and realizes the purpose of continuous heat exchange through the circulation grooves 208.

[0074] The aluminum flat semi-pulse heat pipe bottom plate 1 of the present invention is integrally pressed from a single thin plate (made of aluminum or aluminum alloy) to form the straight cavity protrusion 101 and the U-shaped cavity protrusion 102. The side in contact with the battery module protective film 501 can fully ensure a flat fit. At the same time, the openings of the straight cavity protrusion 101 and the U-shaped cavity protrusion 102 face the photovoltaic battery module 5. In this way, the heating surface of the photovoltaic battery module 5 directly serves as one side of the heat pipe, and a better heat absorption effect can be achieved.

[0075] In addition, the pulse heat pipe of the present invention is only half of the conventional complete circular pulse heat pipe. At the same time, both the aluminum flat semi-pulse heat pipe bottom plate 1 and the aluminum flat semi-pulse heat pipe end plate 2 are integrally processed and formed. Therefore, it has significant cost advantages. Moreover, the operating temperature of the flat pulse heat pipe proposed by the present invention is much lower than the boiling point. In fact, it has been working under a negative pressure state for a long time. The maximum negative pressure is 1 atmosphere. Not only the material requirements are not high, but the encapsulation of the negative pressure is also relatively simple, which can further reduce the cost.

[0076] The present invention separately sets up a set of refrigerant heat exchanger 3. And the refrigerant heat exchanger 3 is combined with the aluminum flat semi-pulse heat pipe end plate 2 to achieve forced refrigeration at the cold end, improving the temperature difference between the cold end and the hot end and accelerating the flow rate of the two-phase flow. At the same time, the present invention uses the pulse heat pipes (i.e., the straight cavity protrusion 101 and the U-shaped cavity protrusion 102) evenly distributed on the back of the photovoltaic battery module 5 to concentrate the waste heat of the photovoltaic battery to a small area at the upper cold end (i.e., the straight groove 206 and the U-shaped groove 207), and then the refrigerant heat exchanger 3 performs centralized heat exchange, which improves the heat collection and heat absorption efficiency.

[0077] In view of the problem of the incompatibility of thermal stress between metallic aluminum and glass 4, the present invention makes a change in the process, using a polyester film to replace glass 4 and introducing it into the photovoltaic cell module 5. However, glass 4 has not been removed. It is just not fixed to the photovoltaic cell module 5 with hot melt adhesive, that is, there is no direct connection between the photovoltaic cell module 5 and glass 4. The remaining planar materials participating in the photovoltaic cell module 5 are bonded together with hot melt adhesive, so that the thermal strains of each layer of materials are basically compatible. At the same time, the aluminum flat plate half-pulse heat pipe bottom plate 1, the aluminum flat plate half-pulse heat pipe end plate 2, the photovoltaic cell module 5 and glass 4 are encapsulated and fixed by the same set of aluminum alloy edge seals 6. The edge of glass 4, the edge of the photovoltaic cell module 5, the bottom plate side plate 103 and the end plate side plate 205 are arranged between the first support plate 601 and the second support plate 602 of the aluminum alloy edge seal 6, and silicone rubber is provided between the first support plate 601 and glass 4 and between the second support plate 602 and the end plate side plate 205 to achieve sealing. The silicone rubber still remains very flexible after curing, can effectively maintain the sealing adhesive force, and at the same time eliminates the difference in thermal stress of the various materials being bonded. In addition, the thermal strain of glass 4 is different from other materials. It can eliminate stress by generating a small displacement through sliding contact with the polyester film, and the flexibility of the silicone rubber just provides this possibility while ensuring the integrity of the seal.

Claims

1. A flat-plate pulsating heat pipe dedicated to the utilization of waste heat from photovoltaic cells, characterized in that: It includes an aluminum flat semi-pulse heat pipe bottom plate (1), an aluminum flat semi-pulse heat pipe end plate (2), and a refrigerant heat exchanger (3). The aluminum flat semi-pulse heat pipe bottom plate (1) is arranged on the back of the photovoltaic cell module (5). There is a glass (4) on the other side of the photovoltaic cell module (5). On the side of the aluminum flat semi-pulse heat pipe bottom plate (1) away from the photovoltaic cell module (5), there are straight cavity protrusions (101) and U-shaped cavity protrusions (102). And the hot ends of any two adjacent straight cavity protrusions (101) are connected through the corresponding U-shaped cavity protrusions (102). The straight cavity protrusions (101) and U-shaped cavity protrusions (102) together with the battery module protective film (501) arranged on the back of the photovoltaic cell module (5) form a closed pulse heat pipe duct cavity (106). The aluminum flat semi-pulse heat pipe end plate (2) is arranged at the cold end of the aluminum flat semi-pulse heat pipe bottom plate (1). The refrigerant heat exchanger (3) is arranged on the aluminum flat semi-pulse heat pipe end plate (2). On the bottom side of the aluminum flat semi-pulse heat pipe end plate (2), there are straight grooves (206), U-shaped grooves (207), and circulation grooves (208). One end of the straight groove (206) is provided with an interface groove (203) buckled on the end of the corresponding straight cavity protrusion (101), and the other end is connected to the adjacent straight groove (206) through the corresponding U-shaped groove (207). The circulation grooves (208) are arranged outside each straight groove (206). And the input end and output end of the circulation groove (208) are both provided with interface grooves (203) respectively buckled on the ends of the outermost corresponding straight cavity protrusions (101). The aluminum flat semi-pulse heat pipe bottom plate (1), the aluminum flat semi-pulse heat pipe end plate (2), the photovoltaic cell module (5), and the glass (4) are encapsulated and fixed by an aluminum alloy edge seal (6).

2. The flat plate pulsating heat pipe dedicated to the waste heat utilization of photovoltaic cells according to claim 1, characterized in that: The aluminum flat semi-pulse heat pipe end plate (2) includes an end plate main body (202), and an end plate screw (201) is arranged on the end plate main body (202). There is a connecting plate (304) outside the refrigerant heat exchanger (3), and the end plate screw (201) passes through the connecting plate (304) and is threadedly connected and fastened with a nut (303).

3. The flat pulse heat pipe dedicated to the waste heat utilization of a photovoltaic cell according to claim 2, characterized in that: On one side of the end plate main body (202), there is a perfusion pipe (204), and on the other side, there is a transition groove (209). And the perfusion pipe (204) is communicated with the transition groove (209), and the transition groove (209) is communicated with the circulation groove (208).

4. The flat pulse heat pipe dedicated to the waste heat utilization of photovoltaic cells according to claim 1 or 2, characterized in that: One end of the refrigerant heat exchanger (3) is provided with a refrigerant medium inlet pipe (301), and the other end is provided with a refrigerant medium outlet pipe (302).

5. The flat-plate pulsating heat pipe dedicated to the waste heat utilization of photovoltaic cells according to claim 1, wherein: The aluminum flat semi-pulse heat pipe bottom plate (1) is formed by pressing a whole sheet of plate to form the straight cavity protrusions (101) and U-shaped cavity protrusions (102).

6. The flat-plate pulsating heat pipe dedicated to the waste heat utilization of photovoltaic cells according to claim 1, wherein: The photovoltaic cell module (5) includes a photovoltaic cell group layer. And on one side of the photovoltaic cell group layer, there is a polyester film, and on the other side, there is a battery module protective film (501). There is a glass (4) on the side of the polyester film away from the photovoltaic cell group layer. The photovoltaic cell group layer is bonded to the polyester film and the battery module protective film (501) through hot melt adhesive respectively.

7. The flat pulse heat pipe dedicated to the waste heat utilization of photovoltaic cells according to claim 1, characterized in that: The aluminum alloy edge seal (6) includes a frame (605), and inside the frame (605), a first support plate (601), a second support plate (602), and a third support plate (603) are sequentially provided. At the edge of the aluminum flat plate semi-pulse heat pipe bottom plate (1), there is a bottom plate side plate (103) without a straight cavity protrusion (101). Outside the end plate main body (202) of the aluminum flat plate semi-pulse heat pipe end plate (2), there is an end plate side plate (205). The edge of the glass (4), the edge of the photovoltaic cell module (5), the bottom plate side plate (103), and the end plate side plate (205) are sequentially arranged between the first support plate (601) and the second support plate (602), and silicone glue is provided between the first support plate (601) and the glass (4) and between the second support plate (602) and the end plate side plate (205).

8. The flat pulse heat pipe dedicated to the waste heat utilization of photovoltaic cells according to claim 7, characterized in that: The displacement of the end plate main body (202) is limited by the second support plate (602) of the aluminum alloy frame. An end plate screw (201) is provided on the end plate main body (202), and the third support plate (603) is arranged above the end plate screw (201). The refrigerant heat exchanger (3) passes through and is exposed between the respective third support plates (603).

9. The flat plate pulsating heat pipe dedicated to the waste heat utilization of photovoltaic cells according to claim 7, characterized in that: A connecting plate (606) is provided between the second support plate (602) and the third support plate (603) of the aluminum alloy frame, and the frame (605), the second support plate (602), the third support plate (603), and the connecting plate (606) enclose a hollow tube cavity (604).

10. A manufacturing method of a flat pulse heat pipe dedicated to the waste heat utilization of a photovoltaic cell according to claim 1, characterized in that: It includes the following steps: Step 1: Place a polyester film on the glass (4); Step 2: Place a hot melt adhesive film A on the polyester film; Step 3: Fabricate a photovoltaic cell group layer on the hot melt adhesive film A; Step 4: Place a hot melt adhesive film B on the photovoltaic cell group layer; Step 5: Place a protective insulating film on the hot melt adhesive film B to form the battery module protective film (501); Step 6: Use a hot pressing process to melt the hot melt adhesive film A and the hot melt adhesive film B, and bond the glass (4), the polyester film, the photovoltaic cell group layer, and the battery module protective film (501) together, where the polyester film, the photovoltaic cell group layer, and the battery module protective film (501) form the photovoltaic cell module (5); Step 7: Open the straight cavity protrusion (101) of the aluminum flat plate semi-pulse heat pipe bottom plate (1) and the aluminum flat plate semi-pulse heat pipe end plate (2) which are integrally connected by welding upward and heat, and the heating temperature is a set temperature above the melting point of the hot melt adhesive; Step 8: Apply liquid hot melt adhesive on the integrally formed aluminum flat plate semi-pulse heat pipe bottom plate (1) and aluminum flat plate semi-pulse heat pipe end plate (2); Step 9: Use a hot pressing process to press the integrally formed aluminum flat plate semi-pulse heat pipe bottom plate (1) and aluminum flat plate semi-pulse heat pipe end plate (2) onto the battery module protective film (501) on the back of the photovoltaic cell module (5); Step 10: Fix the refrigerant heat exchanger (3) to the aluminum flat plate semi-pulse heat pipe end plate (2); Step 11: Use the aluminum alloy edge seal (6) to encapsulate and fix the aluminum integrally formed flat plate semi-pulse tube bottom plate (1), the aluminum semi-pulse tube end plate (2), the photovoltaic cell module (5), and the glass (4).

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