JP2012047405A - Sunlight cogeneration module - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve many problems associated with structures and materials of a sunlight cogeneration panel which acquires heat as well as electric power so as to embody the sunlight cogeneration panel which is promising as a product since it is difficult to attain practical effect as compared with commercial electric power because solar cells currently have an efficiency of approximately 13% of conversion from sunlight energy to electric power, a device needs to have a large light reception area, and an output electric power price thereby increases.SOLUTION: Structures, materials, and producing methods for joining together a power generation cell assembly in a flat plate shape, a module substrate on which the power generation cell assembly is mounted, and a cooling medium conduit are found, and then combined to show that a high-reliability low-priced module can be manufactured as a product and to clarify a basic technique for putting the sunlight cogeneration module to practical use.

Description

At present, solar power generators and solar water heaters (solar heat collectors) are attracting attention not only in Japan but also overseas, reducing consumption of petroleum resources, preventing global warming, suppressing the rise in prices of petroleum resource-related components, Expansion is expected as a device system that meets other global environmental requirements and social needs. However, the scale of the market is less than 100,000 units sold every year for home use in Japan. On the other hand, there are 4 million units of gas / oil hot water supply units and 7 million units of home air conditioners.

The reason why the market scale of the single-function solar power generation device or the solar water heater itself does not increase is that the output effect is insufficient for the investment price of the device. That is, the period for collecting the initial investment (PBT) is as long as 7 years or longer, that is, it takes 30 years to recover the investment in a solar power generation device for home use, or conversely, the service life of the solar water heater is 10 years or less. This is because there are problems.
In terms of energy efficiency, the conversion efficiency (ECR) in which solar energy irradiated to the photovoltaic power generation device is converted into electric power is about 12 to 14% in a device in practical use, and the remaining energy amount 88 to 86% are not available. This requires a large-area device as an energy supply device, and the generated power cost is nearly twice as high as 23 yen / kWh, which is the cost obtained with commercial power, that is, a high price of about 40 yen / kWh. The initial investment payback period has been extended to about 40 years, which is the main reason why it has not spread. For this reason, new technology development for improving the conversion efficiency (ECR) of the power generation cell itself is expected.
For example, a 3kW solar power generation system for homes usually requires a light receiving area of 30 square meters, which not only imposes great restrictions on installation space but also increases the cost of actual installation work. It is a factor and a factor that hinders the spread.
As a result, while the commercial grid power is currently around 23 yen / Kwh in Japan, the output power price in the case of a solar cell alone is about 30-40 yen / kWh assuming that the lifetime is 20-25 years. For this reason, its spread has not progressed.

Therefore, recent research and development on solar power generators has been remarkable with the aim of solving these problems. Research is also progressing on the use of silicon crystal cells, such as polycrystallization, thinning of silicon crystals, improvement of power generation characteristics of crystal bodies and improvement of light reception characteristics of crystal surfaces.
In addition, a silicon amorphous material formed on a glass surface or a plastic film surface or a material obtained by laminating the silicon amorphous material with a silicon crystal has been improved. A material in which this amorphous is formed on a window glass for building materials and used as a window material for a building or the like so that the window generates electricity has been put into practical use. In addition, a material that is made of a material different from silicon such as copper or indium and deposited on a glass substrate as a cell material is also promising as an alternative to a silicon-based cell to avoid resource shortage. Solar cells using a thin aluminum plate as the cell electrode substrate have also been commercialized. This is a structure in which small spherical silicon with a diameter of about 1 mm is embedded in the mortar-shaped holes of an aluminum substrate in which a large number of mortar-shaped ridges are formed, and the surface of the mortar-shaped holes gathers in spherical silicon. It has the function of reflecting light and has the function of an electrode. This aluminum substrate electrode type power generation cell has a structure that is extremely effective for improving the performance of the solar cogeneration apparatus, which is the subject of the present invention, that the substrate is made of aluminum having good heat conductivity.
In other words, there are many types of substrates for power generation cells such as silicon itself, glass plates, resin plates, and aluminum plates.

The present invention relates to the structure of a solar module for more effectively using solar energy using these power generation cells, and is used for consumer use, particularly for home use, business use, and industrial use. The present invention relates to a solar energy composite usage module (hereinafter referred to as a solar cogeneration module or a solar cogeneration module) that receives sunlight and simultaneously generates power and supplies heat.
Research and development of solar cogeneration modules that can obtain electric power and heat with a single module have been studied for several decades. That is, a metal plate as a heat sink is installed on the back surface of the power generation cell, and the heat generated in the power generation cell is collected through water and refrigerant in a pipe and a medium passage integrated with the metal plate. According to this method, the light receiving area of the entire module can be reduced compared with the case where the photovoltaic power generator and the solar water heater are installed separately, and the two effects of cost reduction and installation space reduction can be achieved. Equipment installation work can also be simplified. Furthermore, by forcibly cooling the power generation cell, the temperature of the power generation cell can be lowered, and the following effects can be expected.
1. The power generation efficiency of the power generation cell is improved. 2. The temperature rise around the cell can be prevented in areas with high external temperatures such as the tropics and areas resistant to sunlight irradiation, and a long life can be guaranteed.
3. It is effective in preventing the sintering damage of the power generation circuit connecting the modules.
In addition, when used in homes and stores, there is an advantage that electric power, hot water heating temperature and heating temperature can be obtained at the same time.
50-60% of the initial price of the solar cogeneration module aimed by the technical field handled by the present invention can be borne by the module, and as a result, the output power is borne by 40-50% of the initial price. To be reduced. As a result, the output power has a great effect that it can realize a price lower than that of commercial power, that is, a market power price in Japan of about 24 yen / Kwh in 2010.

Therefore, research efforts on this cogeneration module device have been seen in many companies, universities, research institutions, etc. from the past. However, it has not yet been realized as a product.
The reason for this is that it is difficult to ensure practical long-term reliability because it is a highly functional composite made of a complex material.
That is, the material of the power generation cell is made of a material such as silicon or glass that has a very low coefficient of thermal expansion and poor heat transfer performance, while the material used for the heat sink or cooling pipe placed on the back of the material is a metal with high heat transfer performance. The material has a very large linear expansion coefficient. As a result, a close contact structure for enhancing the performance and efficiency of the module and a separation structure for ensuring reliability and ensuring electrical insulation corresponding to a large thermal strain caused by a wide range of temperature changes from minus 20 ° C. to plus 120 ° C. A practical and inexpensive structure and material technology that solves one need has not been established.
2. On the other hand, it is a structure that circulates a cooling medium (generally water, antifreeze liquid) for utilizing heat throughout the entire equipment system installed over a wide range, such as rust due to condensation, medium leakage from joints, etc. There are many reliability risk items, and there is also a problem of the circulation pump life of the medium. Compared to a solar cell system, the practical lifetime is shortened, and there is a risk that it may be halved.
3. The biggest problem is the risk that the power generation cell layer, the heat sink, and the cooling medium conduit that performs cooling will be peeled off due to long-term use. Failure to establish structures, materials, and manufacturing methods to ensure long-term life as a composite structure in harsh operating environments such as snow load, heavy wind pressure and vibration, moisture and moisture, temperature changes, and sunshine is there.
4. In order to solve these problems, the cost of using highly functional materials increases, the structure becomes complicated and the cost tends to increase, and the output improvement effect of cogeneration is offset. In some cases, only the same economic effect can be obtained.
There are problems as described above.

The technology of the present invention is a key element for solving the above-mentioned basic problems, and is for establishing the mechanism, structure, material, and manufacturing method of a solar cogeneration module as a key component of the system.
The technical field is related to the structure to realize the heat transfer characteristics that transfer the strength and heat enough to support the whole module, and the various functions as the foundation for mounting the power generation cell, matching the material characteristics of the power generation cell. .
It is a technology for constructing a module based on a complete flat plate made of metal as a base of the module.
A module substrate as a base of a module structure that has a flat surface and can be commercialized, and a long-term reliable and commercializable product for extracting the heat generated in the power generation cell through the module substrate A cooling structure that can realize a high cost (in the present invention, this is expressed as a cooling medium conduit), and further high productivity for joining the cell, module substrate, and cooling medium conduit can be commercialized. The present invention relates to a manufacturing method capable of realizing high reliability and cost.
Technological development has been promoted by setting the performance and merchandise goals of the cogeneration module targeted by the present invention as follows.
1. Achievement of high conversion efficiency in converting light irradiation energy into electric power and heat: 13-14% or more (equivalent or better power generation characteristics than solar cells)
Heat: 40% or more (equivalent to solar water heater)
Total energy: about 54% (achieving maximum efficiency)
2. Cost target: Achieve a cost increase of 25% or less for solar cell modules 3. Achieve an operating life equivalent to solar cells: 20 years or more (including repair and maintenance) On the other hand, the technology that the present invention is trying to realize is This is a technology for ensuring stable productivity and realizing practical costs regarding the structure of the module for realizing this commerciality, and the basis of this is high reliability and sufficient strength. This is a technology related to the module board with the surroundings and the surrounding structure.

In other words, the core technology related to the solar cogeneration module of the present invention is a technology related to securing the strength of the module substrate, the structure of the entire module, the material of the module substrate, the method of joining the module substrate and the cooling medium conduit, and the structure and material of the cooling medium conduit. is there.

Conventionally, a large amount of research, development, and patent applications on solar cogeneration modules and their application systems have been carried out. However, there is no technical information at a completed level regarding sufficient performance as described above, practical cost realization, and long-term reliability. There are sporadic technical information on the pursuit of technical perfection in these three aspects, so we will introduce it here as background technology.
Against this background, many researches and developments have been made on the technology of the solar cogeneration device for simultaneously obtaining heat from the solar power generation device.
Among them, Patent Document 1 proposes a technique regarding a cooling method using a primary refrigerant based on a combination of a heat collecting panel and a heat collector. However, there is no structure that becomes the substrate of the module, and the strength for maintaining the entire flatness is not sufficient. Instead, since the refrigerant passage is formed by bonding or welding the upper heat collecting plate and the lower heat collecting plate, the risk of refrigerant leakage is great. There is no ingenuity on mitigating thermal strain on the power generation cell of the upper heat collecting plate made of aluminum, and there is a great risk of damage to the power generation cell and malfunction due to repeated heat cycles during long-term use. Since the upper heat collecting plate and the lower heat collecting plate have an aluminum block structure, the weight of the upper heat collecting plate and the lower heat collecting plate increases, and there is a problem of installation workability in terms of cost increase and weight increase. In view of the above, commercialization is very difficult with such a structure.
Patent Document 2 presents the basic structure of a cogeneration module, but the heat loss through the glass from the top surface of the cell decisively degrades the performance, and the components that serve as the basis for ensuring the planar strength of the entire module are Without white glass and heat collector, the overall strength is insufficient for loads such as wind pressure vibration due to snow and typhoons, etc., the heat collecting plate is cut into pieces, and the reliability of joint strength such as EVA film that adheres to the film The property deteriorates remarkably and can be peeled off after several years of use. In addition, each EVA bonding is thermally welded in a separate process, and there is a concern about a decrease in productivity and quality compared to a method in which the whole is bonded by a single heating operation.

Patent Document 3 is excellent in that the planar metal plate serves as a support, that is, the entire base and maintains strength and shape accuracy. However, the structure in which the corrugated metal plate is welded to the flat metal plate to form a water passage and is connected to the header pipe has many welding points, and its manufacturing reliability is due to the occurrence of leakage of the cooling medium of the module. It is a risk. There are many worries about various factors during production, long-term external force such as typhoon, and rust caused by rain, moisture and air pollution. What is important is that there is a risk of damage or breakage of the power generation cell due to warping and deformation of the flat metal plate due to this welding, unevenness on the surface of the power generation cell, deformation of the top surface of the flat metal plate due to external stress, etc. Furthermore, it is necessary to devise, and it cannot be said that it can be adopted as it is.

In Patent Document 4, a back sheet made of an aluminum plate is provided on the back surface of the photovoltaic power generation cell, and a heat collecting plate for pressing the heat collecting tube is bonded to the back sheet. The heat collecting plate is mechanically pressed by a pin and bonded. Since the heat collecting plate made of small metal pieces is small, the adhesion easily peels off from the end face when the module vibrates due to wind pressure due to a typhoon or the like. In order to prevent this, the prior patent is recognized as an extremely effective technique. The method of mechanically fixing the back sheet with metal pins is thought to contribute to maintaining the strength of the substrate and improving the bonding strength and reliability. However, the manufacturing process of installing this pin on the metal backsheet requires many processes, and the deterioration in productivity is thought to cause an increase in manufacturing cost.

Patent Document 5 is noted in that a member corresponding to a module substrate is used as the flat plate member 10. However, the effectiveness is halved in that the heat collecting plate 5 is provided separately from the flat plate member 10. The present invention presupposes that the module substrate as the strength member has a heat collecting effect as a heat sink to reduce the weight, reduce the joint portion, and reduce the cost.
Although the details have been described above, it can be seen that some problems remain to be achieved in the conventional technology. It is necessary to achieve a cost that can be sold as a product with high productivity and high reliability, and at a practical price, and many techniques related to the structure, material, and manufacturing method necessary for this purpose must be established.
Patent Document 6 shows an example in which a corrugated member made of an equivalent member is welded to the lower surface of a flat plate member (module substrate), but this indicates the strength of the flat plate member and suggests distortion and deformation due to welding. There is no proposal from an important point of view to ensure the strength by making the plate pressure of the flat plate member thicker than that of the corrugated member.
The above is one end of conventional related field technology. The present invention intends to provide a technique for keeping the strength, flatness accuracy, and thermal expansion stress response level of a module substrate at a practically sufficient level.

Japanese Patent Laid-Open No. 10-62017 JP 2003-234491 A JP 2002-39631 A JP 2005-214430 A JP-A-11-325610 JP 2002-39631 A

Summarizing the above contents as a study topic, the important items are organized as follows. That is, the following characteristics are required for the structure and materials of the solar cogeneration module.
(1) Structural strength The power generation cell and the cooling mechanism are stably and firmly held, and structures, joints, and materials that can withstand stresses such as snowfall, earthquakes, typhoons, and deformation distortion of the entire device are required. For this reason, it is considered that the cooling mechanism itself has high strength or a structural substrate with high strength is required separately from this. This structural substrate needs to be able to be manufactured at a low cost and at a low cost with a material resistant to rust, etc., with the power generating cell portion held on the upper surface and the cooling heat collecting portion held on the lower surface with sufficient strength and reliability. Therefore, this substrate is a metal material on a flat plate, and an iron plate or a steel plate stainless steel plate having a small thermal expansion coefficient is selected in terms of minimizing thermal expansion strain with the power generation cell.
(2) Flatness The strength member or the upper surface of the substrate needs to be a highly accurate plane in order to support the power generating cell that is easily broken.
(3) Thermal strain Since this strength member or substrate is bonded in a thermal contact relationship with the power generation cell material, it is also important to be able to cope with stress strain caused by thermal strain caused by temperature change. That is, silicon crystal and glass are materials having a very small linear expansion coefficient with respect to temperature change (2.7 to 3.5 / million / ° C.), whereas in aluminum, deformation due to thermal strain more than ten times occurs. Therefore, the difference in strain must be alleviated and still thermal bonding must be maintained.
(4) Heat transfer performance When taking out the heat generated in the power generation cell, it is necessary to make the power generation cell and the cooling mechanism as close as possible, and all parts absorb the relative strain due to temperature changes as described above. It is required to have a structure and material that can be used. Copper, aluminum, iron, glass, and resin are excellent in heat conduction in this order, while the thermal expansion coefficient is high in the order of resin, aluminum, copper, iron, glass, and silicon substrate. Utilizing these characteristics, it is required to use structures and materials that efficiently extract warm heat and absorb mutual thermal strain.

(5) Cooling medium leakage and cooling circuit long-term reliability Water and antifreeze are used as the cooling medium, but this medium is stable and free of leakage over a period of 20 years or more equivalent to the operating life of the power generation cell. In order to operate, a cooling mechanism having a simplified structure and a cooling medium pipe structure constituting the cooling mechanism are required. Basically, it is desirable to use a metal material that can withstand long-term use without any welding or bonding. It is important to completely prevent leakage of the welded structure of the two plates. As a method for solving the problem of rusting of the cooling pipe, a method of making the cooling circuit made of resin is also effective, but the resin has a larger linear expansion coefficient than aluminum (20 to 90 / million / ° C) and extremely high thermal conductivity. There is a problem of being small (0.3 W / m ° C.).
(6) Reliability of joining the power generation cell to the cooling pipe There are many methods such as brazing and bonding for joining the cooling pipe to the module substrate, but the method for simply joining the pipe to the board is the heat transfer in the board. No suitable method can be found from the viewpoint of characteristics, heat transfer characteristics around the cooling pipe, peeling of the joint, deformation of the substrate, and the like. As described below, this part is made of aluminum, which functions as a cover material for the lower surface for hot melt bonding and functions to effectively transfer heat from the substrate to the cooling pipe, and is lightweight and low cost. A method such as covering with a thin plate is suitable. It is desirable that the shape also satisfies the needs described in detail below.
The module cell is sandwiched between the power generation cell, cooling pipe, and cover material so that heat can be transferred, and there is no peeling or material damage due to the difference in the amount of thermal strain between the materials. It is necessary to perform bonding by a bonding method that is excellent in performance and superior in manufacturing cost.

(7) Heat resistance and weather resistance The operating environment of the module is a temperature range: -20 ° C to 50 ° C, a humidity range: 10 to 100%,
Wind speed: 40 m / sec is assumed. The maximum module temperature when operating under this environmental condition is about 125 ° C. when the cooling medium function is stopped. The reason why the temperature is so high is to reinforce the heat insulation of the upper surface, the lower surface and the outer periphery as a heat collecting device.
Sufficient security measures must be taken for freezing in a low temperature environment close to -20 ° C.
(8) Productivity The problem is related to the joining of the power generation cell and the cooling medium conduit. Adopting a complicated manufacturing method in order to ensure the reliability described above increases the cost and must be avoided. Since a module uses a large number of modules, it is necessary to make its production productivity much more sophisticated than that of an ordinary single device.

(9) Costs and material costs Development of structures, materials and manufacturing methods that satisfy the above functional requirements requires advanced technology and at the same time makes practical application difficult. Furthermore, since those materials that satisfy these functions are highly functional in terms of their materials and structure, their costs increase, making it difficult to put them into practical use as consumer devices.
(10) Manufacturing equipment investment Cogeneration modules tend to have a complex structure for realizing a composite function, and the manufacturing process usually requires several processes, which increases the manufacturing equipment investment and manufacturing costs. Soaring prices and increasing initial capital investment are barriers to business participation.
As described above, various techniques of the present invention have been researched and studied with the aim of realizing successful development of modules satisfying (1) to (10).

The module structure, material, and manufacturing method that can solve all the above problems have not been clarified so far. Summarizing these, the following three items are important as the target issues for the solar cogeneration module, and the technology of the present application is also aimed at realizing a module aiming at this.
(A) As an output energy target, electric power is equivalent to that of a solar cell alone, and thermal performance is equivalent to that of a solar water heater alone.
(B) Achieve 20 years of operating life and 30 years assuming service maintenance.
(C) 20-30% cost increase as a module cost based on single function solar cell
The target is below.
This is because the set values of the above target tasks are estimated to be able to achieve the maximum target of halving the output energy price by realizing this.

The structure of the module targeted by the present invention is that the power generation cell is installed in a state of being in intimate contact with a metal module substrate (heat sink flat plate), and the heat generated in the power generation cell is not dissipated to the surroundings without the heat sink. By collecting heat by transferring heat to a flat plate, the recovery rate of solar energy is increased, and a high recovery rate of around 50% can be obtained while the solar cell has a recovery rate of around 12%. .
Therefore, in the case of a home cogeneration apparatus, a practical effect can be satisfied even if the total light receiving area is reduced to about 10 to 15 square meters as compared with a single photovoltaic cell system (about 30 square meters). On the other hand, the light receiving area of the conventional solar water heater is larger than that of 4 to 6 square meters, but it has a power output, and the amount of heat obtained is sufficient, so it can be used not only for hot water supply but also for heating. It is advantageous that the utility value of the output energy is high.

The present invention presents a basic technical concept for solving the above-mentioned many problems. The basis of the technology concept is a structure in which a very strong flat plate structure can be obtained by the structure of the solar cell core solidified in seven layers around a metal module substrate, and the structure is uniformly bonded over the entire plane area. Is to ensure extremely high reliability against peeling of the joint and high heat transfer performance. At the same time, it has presented many technical ideas that can achieve high manufacturing productivity, simplified manufacturing equipment, and reduced product cost.

The cell upper surface cover is a light-transmitting lid that protects the power generation cell assembly from the outside, and is attached to the upper surface of the power generation cell assembly with a bonding resin such as ethylene vinyl acetate copolymer resin (EVA). In addition, it protects from moisture and gases in the ambient air, and holds the power generation cell assembly structurally. Transparent and chemically stable to sunlight, and flexible and flexible materials like films are used, but glass plates are sometimes used, but usually chemically stable fluorine-based resin films are used. There are many things. Assembling the power generation cell means a circuit in which a power generation cell to be incorporated in the module is formed to generate power and output.

The metal module substrate is a flat metal plate arranged between the power generation cell assembly and the cooling medium conduit, and both are supported on the upper surface and the lower surface to constitute the solar cell core (light receiving output unit), It is the foundation for the strength of the entire module. Of course, it is important that the power generation cell is bulk silicon that is easy to break, and that the flatness, distortion, and deformation of the surfaces of the members to be joined are important. is there.
Its materials are iron plate, aluminum plate, stainless steel plate and steel plate, surface coating and plating, and resin coating. The thickness is selected from about 0.5 mm to 1.2 mm in consideration of strength, weight, cost, and the like. For the surface treatment, an optimum treatment method is selected in consideration of long-term reliability such as improvement in absorption characteristics of received light, electrical insulation, and rust.

The material of the module substrate is selected mainly in consideration of cost reduction, heat transfer performance, thermal strain characteristics with the power generation cell, and joint reliability with the cooling medium pipe. One of the reasons for the proposal of the present invention in which the module substrate and the cooling medium conduit are not formed as a single part but as a separate part is that a module substrate material optimum for the type of power generation cell can be freely selected. The second reason for using the module substrate separately from the cooling medium conduit is that it is easy to make the top surface completely flat, so that deformation and distortion to the cell when the power generation cell is mounted can be minimized. It is.

An ethylene-vinyl acetate copolymer resin (EVA) is used as a heat-responsive bonding resin that is transparent and softened at about 150 ° C. to bond between the cell top cover and the power generation cell and then soften at about 150 ° C. ), A film such as ethylene methyl methacrylate copolymer resin (EMMA). The power generation cell assembly is sealed in a structure sandwiched between the EVA bonding resins, and is fixed, held and protected.

The bonding resin on the lower surface of the power generation cell assembly is not required to be transparent as in the case of the EVA described above, but since it requires electrical insulation with the metal module substrate, an insulating resin film is laminated in a sandwich shape. Instead of using an EVA film or an insulating resin film, a module substrate in which an insulating resin is coated on the surface of a metal flat plate may be used.
A heat-responsive bonding resin is also used for bonding the module substrate and the cooling medium pipe. The above-described transparent EVA may be used, or a heat-responsive resin film that is not necessarily transparent may be used.

The three-layer heat-responsive bonding resin described above is laminated in seven layers by placing it in a sandwich between the four-layer members described above. This is installed in a lamination treatment tank and heated to about 150 ° C. for several tens of minutes to create a vacuum environment, so that the heat-responsive bonding resin dissolves and fills between the layers and crosslinks. Join the four-layer members. Since the bonding resin EVA retains flexibility like a hard rubber even after it is cross-linked and hardened, it can be tightly adhered without fixing the cell top cover, power generation cell, module substrate, and cooling medium pipes to each other. Join. This flat part that is formed in this way and receives light and outputs power and heat is called the light receiving output part, and it is incorporated and combined with a cover glass, frame, bottom insulation, etc. to generate power and heat ( A module capable of simultaneous output) is defined as a solar cogeneration module in the present invention.

As described above, the bonding resin is flexible even after being fixed, and a sufficient thickness is generated in the power generation cell to play a role as a buffer between strain and stress between the four members. In order to be able to efficiently transfer the solar heat to the cooling medium in the cooling medium pipe line through the entire plane area, a thin wall thickness is necessary so that the heat transfer is not hindered. Things are important. In the case of EVA, a wall thickness of about 0.2 to 0.8 mm is practically selected.
The joining work of the present invention is characterized in that it can be realized by performing only a laminating work and, if necessary, a heat retaining work for crosslinking or both.

The important thing is that the above three-layer joining can be completed by one processing step. In addition to avoiding deformation of parts and work mistakes due to various types of processing such as bonding, welding, brazing, screw tightening, etc., which are performed in the case of normal joining and joining processing, high production is also avoided. This has extremely important advantages in commercialization and commercialization, in which the capital investment for manufacturing can be minimized, as well as the reduction of the manufacturing cost and the manufacturing cost.
Thus, the solar cell core as a seven-layer structure as a whole can be manufactured by the simplest method.
The seven-layer solar cell core has the following features due to its manufacturing characteristics.
The strength is high because of the three-dimensional structure of 1 and 7 layers.
2. Excellent heat transfer characteristics because all joint surfaces are in close contact.
3. Since the bonding resin layer is interposed in one layer, it has a function of relieving mutual thermal strain. In particular, the presence of a layer called a module substrate makes it possible to select and use a metal material optimum for thermal strain buffering.
4. Since the entire area is bonded, it is highly reliable against peeling due to the vacuum effect.
5. Productivity is high and manufacturing equipment investment is small.
6. Since the members of the intermediate layer can be completely isolated from the outside world, rust, deterioration, etc. can be prevented.
7. There are no other joining processes such as welding and screw occupation, the risk of manufacturing defects is small, and it is easy to improve the reliability of long-term use of products.
8. Assembling by heat treatment joining, the structure, material, shape, etc. of members to be joined can be freely selected, and an optimum combination is possible.
9. As a result, the cost is superior.
It is possible to obtain extremely superior results in commercialization.

However, the major issues in assuring long-term reliability as equipment that is expected to have an operating life of 30 years or more under severe operating environment conditions are module substrates, cooling medium conduits, and cooling medium conduit covers This is the long-term reliability of bonding between the three metal members.
If this portion is peeled off, the power generation cell cannot be cooled, which leads to a failure in the power generation cell, deterioration of the EVA bonding resin described above, and separation, resulting in a fatal failure. The three metal members have different materials due to peeling stress due to thermal strain, and furthermore, peeling stress due to warp deformation due to internal strain during manufacture. Further, the module substrate is warped or deformed due to the stress, and as a result, the power generation cells and the electric circuit members connecting the cells are deteriorated or broken.

Claim 1 presents the most important and effective method for solving the above problems.
In order to maintain the flatness and strength of the module substrate, the module substrate uses a high-strength material such as an iron plate or stainless steel plate, and a flat plate with a high flatness, while the cooling medium pipe connected to the module substrate is usually a copper tube. Use. Therefore, a cooling medium pipe cover is used to firmly join the cooling medium pipe line to the back surface of the module substrate. In this case, for example, if the cover is made of the same material as that of the module substrate and made of a flat metal plate, the molding distortion during manufacture or the thermal expansion distortion during use due to long-term use of 10 to 20 years Deformation due to warpage or the like causes separation of the resin joint portion, or defects such as deterioration of the resin due to intrusion of moisture from the generated gap.

  Accordingly, claim 1 presents the most reliable method for avoiding this, and the strength of the cooling medium conduit cover is reduced, the strength of the module substrate is increased, and the cooling medium conduit cover is separated from the module substrate. In this technique, the flat shape of the module substrate is not distorted. Specifically, when the pipe cover is made of metal, the thickness of the pipe cover is equal to or less than that of the module substrate. If the same type of metal plate, such as galvanized steel plate or stainless steel plate, is used, if the thickness of the duct cover is thinner than the thickness of the module substrate (especially 50% or less is better), the mutual Even if distortion occurs due to interference, the strength of the module substrate is high, so the flatness is not impaired, the mutual stress can be absorbed by deformation and familiarity of the pipe cover, and the power generation cell and electric circuit on the upper surface are not damaged, The risk of peeling the bonding resin between each other is greatly reduced. If the plate thickness is 50%, the bending strength is a quarter of the calculation, and the cooling medium conduit cover is easily deformed along the module substrate.

Even when an aluminum plate or module board galvanium steel plate (a type of galvanized steel plate) is used for the cooling medium duct cover, mutual stress is likely to occur due to the high coefficient of thermal expansion of aluminum, but the thickness of the aluminum plate Is thinner than the thickness of the steel plate (for example, when the aluminum plate is 0.3 t and the steel plate is 0.8 t), the aluminum plate becomes familiar with the steel plate, and the deformation of the module substrate is extremely small, which leads to mutual peeling. It turns out that there is almost nothing. On the other hand, when the same 0.8mm galvanium steel plate is used, thermal expansion stress hardly occurs, but due to the peeling force due to the warp of each other plate caused by internal strain during production, the temperature during daily repeated use And we grasp the phenomenon that the resin joints deteriorate and peel due to stress due to moisture. If the thickness ratio is about 50% (that is, twice or more), it is possible to sufficiently prevent mutual peeling by appropriately performing resin bonding, but this figure is a test evaluation on a certain scale. Based on experience. The ratio of wall thickness to be selected should be determined in consideration of the module configuration and materials.
Of course, reducing the thickness of the material for the cooling medium pipe cover can also be expected to reduce the material cost and reduce the weight of the entire module.

In claim 2, in addition to claim 1 or independent of claim 1, a technique for enhancing the peel strength of the resin joint portion and presenting a completeness is presented. In other words, in order to more securely fix a part of the cooling medium pipe line (for example, the folded end part of the bent meandering pipe) to the module board, it is welded to the module board with a small U-shaped metal band that matches the pipe shape. And fix it. What is important here is a fixed band that covers the entire pipe line as discussed in the prior art (this is a cooling medium pipe cover that covers the front of the module board without being removed). The module substrate is heated and deformed during welding and deforms due to expansion and contraction stress with the cooling medium pipe cover during use, and its flatness is not maintained, and the module substrate is deformed. There is a risk of inducing defects such as breakage of the interconnector of the electric circuit connecting the two. Furthermore, in this method, since a heat-responsive resin cannot be laid between the module substrate and the cooling medium conduit cover, a gap is not formed between the cooling medium conduit and the module substrate even if the bonding strength is secured by welding. Therefore, there is a decisive problem that sufficient heat transfer characteristics cannot be secured.

Bonding between the cooling medium pipe line and the module substrate by the fixed band is strengthened, and since the fixing band is made partly, it is possible to cover the cooling medium pipe line cover from above and bond with the heat-responsive resin between them. Thus, it is possible to realize strong bonding by both metal welding and resin bonding. Furthermore, the vacuum high-temperature lamination process is performed in a very simple process by sandwiching a heat-responsive resin film between the module substrate on which the cooling medium conduit is welded and fixed by a band and the cooling medium conduit cover. There is an advantage that it is possible to manufacture a light receiving / outputting part having a configuration (a part that receives light and outputs electric power and heat, which is the core of the solar cogeneration module).
In the third aspect of the present invention, the metal band shown in the second aspect is made thin and a metal material having a low electric conductivity is used to make the heating temperature and area when welding the metal band to the module substrate more local. This is a technique for minimizing adverse effects such as distortion caused by welding heat on the module substrate. When the same iron plate material as that of the module substrate is used, the metal band can be melted and welded before the module substrate is deeply melted by reducing the plate thickness. As a result, the influence of welding heat on the module substrate can be reduced. The same effect can be obtained by using a plated iron plate for the module substrate and a stainless steel plate having a smaller thermal conductivity and electrical conductivity than the plated iron plate for the metal band. For safety reasons, it is desirable that the thickness of the metal band be about 50% or less of the module substrate.

According to the fourth aspect of the present invention, the cooling medium passage plate is not attached to the lower surface of the module substrate, but a cooling medium passage plate formed by denting a portion that becomes a medium flow path under the module substrate is welded and cooled between them. In the case of forming the flow path of the medium, an important technique is presented for the case where the cooling medium passage plate is welded to the module substrate. This welding is usually performed by seam welding. Since this seam welding increases the range and length of the welding, the welding heat deforms the module substrate and leaves a great stress. As a result, the flatness of the module substrate is impaired, and the flatness is further affected by external stress (temperature change, wind pressure due to typhoons, vibrations, etc.) during installation and use, such as power generation cells and interconnectors. It leads to defects such as breakage. Therefore, reducing the thickness of the cooling medium passage plate to be welded to the thickness of the module substrate is extremely effective as a countermeasure against the occurrence of this defect. The effect is even greater if the plate pressure of the cooling medium passage plate is set to about 50%.

When a medium with a large amount of water is passed between two flat plates configured in this way, stainless steel is often used for both flat plates. In this case, using stainless steel having a smaller thermal conductivity (that is, electric conductivity) than the module substrate for the cooling medium passage plate is extremely effective in obtaining the above-described effects. If different stainless steel plates are used in this way, it is possible to minimize the thermal deformation strain on the module substrate even when seam welding is performed, and a necessary and sufficient effect can be obtained by combining both the effects of the plate thickness. be able to.
At the same time, it goes without saying that reducing the thickness of the cooling medium passage plate is advantageous in reducing the weight of the module and reducing the cost.

The fifth aspect of the present invention is a technique related to the material selection of the module substrate. In order to prevent the power generation cell from being damaged by minimizing the difference in coefficient of thermal expansion from the power generation cell, the material must be a metal material instead of resin because of the need to have strength to support the entire module. An iron plate or an iron steel plate or a ferritic or martensitic stainless steel plate is selected. Copper plates and aluminum plates are not suitable for module boards because of their high cost or low strength and a high coefficient of thermal expansion. In the methods of claims 1, 2, and 3, an iron plate, particularly a plated iron plate is used, but since a heat-responsive resin is used as a bonding material on both sides, it is necessary to use an expensive stainless steel plate to prevent corrosion deterioration due to complete sealing. The nature is thin.

In the method of claim 4, stainless steel is used because an aqueous antifreeze is used as a cooling medium, but it is necessary to use chromium-based stainless steel (ferrite-based, martensitic-based) having a small linear expansion coefficient.
The technique shown in claim 6 is for the purpose of using a power generation cell that is vulnerable to deformation stress, such as a power generation cell made of crystalline silicon, in order to ensure the flatness and strength of the module substrate that the present invention intends to realize. It is assumed that.

Claim 7 is because the above-mentioned solar cogeneration module uses a material that easily generates deterioration or rust due to moisture, such as an iron plate, a plated iron plate, and a heat-responsive bonding resin, as a module substrate. Exposing the end face of the outer periphery of the part to the outside air creates a risk of impairing long-term reliability. Therefore, it is necessary to devise so as not to cause deterioration due to rust and to seal the end face by being buried in a bonding resin film such as EVA sandwiching the entire substrate and not contacting with the outside air. In this case, the planar shape dimensions of the module board made of iron plate are made small so that the upper and lower surfaces are completely covered with the bonding resin. With this technology, it is possible to use the most inexpensive and excellent iron plate as a module substrate and prevent deterioration of the bonding property due to moisture and iron rust as the biggest problems.
If this is not possible, it is important to cover with a sealing resin.

The present invention relates to a cooling medium pipe cover. By using a molded product of an aluminum plate, there are advantages such as improved heat transfer performance, lighter module, and easier manufacturing. However, aluminum is a material with an extremely large thermal expansion coefficient, and when an iron plate with the smallest thermal expansion coefficient is used for the module substrate, the difference in mutual expansion coefficient is greatly strained with changes in temperature during production and use. As a result, there is a possibility of causing defects such as the entire warp of the light receiving output part, peeling of the resin joint part, or, in the worst case, damage to the power generation cell or the interconnector. Although the technique of claim 1 is effective in preventing this, it is not sufficient when the material is aluminum. In order to alleviate the expansion and contraction of the cooling pipe cover formed by press-molding this aluminum plate, a fine cut-through bead and a cutting line are provided, or the whole is divided into four or more parts, which are bonded to the aluminum foil adhesive tape. It is effective to use a cooling medium pipe cover that is repaired and integrated with each other.

The following effects are considered to be obtained by the present invention.
1. Present the basic system and basic technology for the construction of a solar cogeneration module that has the function (cogeneration) to simultaneously acquire power and heat from the same cell using sunlight. Made possible.
2. Structure, materials and other basics necessary for the design and manufacture of solar cogeneration modules
Clarified specific technology.
3. The technology presented in the present invention can realize a high-performance and practical solar cogeneration module with high reliability, long life, high productivity, and cost response capability.
4. It is possible to make a prospect of realizing a distributed energy utilization system incorporating this module, and studies for realizing this system can be advanced.
5. It is expected that this system will be realized and spread, and it will be possible to contribute to the global environment protection with excellent energy price and low CO2 generation.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
FIG. 1 shows a cross-sectional structure of an example of the present invention of a solar cogeneration module. Sunlight sequentially from the top surface is the module top surface glass cover 1, the top heat insulating layer 2 which is an air layer of about 30 mm, the cell top surface cover 3 which is a fluorine-based gas barrier film, and the bonding resin A6 which is a heat-responsive bonding resin EVA. Is transmitted to irradiate the power generation cell assembly 4. The power generation cell is a thin plate of single crystal silicon, and the power generated by each power generation cell flows through the power generation cell connector line 5 through the entire power generation cell assembly to increase the voltage and is output to the outside.
On the other hand, most of the remaining solar energy generated in the power generation cell is changed to heat, and the power generation cell is heated, and the heat is sandwiched between the bonding resin B7 and the intermediate layer of the bonding resin B7 (not shown). The electric insulating film, the module substrate 8, the bonding resin C12, the upper flat surface 17, the copper pipe-made cooling medium pipe 10 and the thin aluminum plate are transferred to the cooling medium pipe cover. Let it heat.

The cooling medium 11 is water or a propylene glycol solution that is an antifreeze, and receives the heat generated on the surface of the power generation cell 4 as described above to cool the power generation cell assembly 4.
Here, the module substrate 8 uses a galvanized iron plate having a thickness of 1 mm, and bears the overall strength as a skeleton of the entire module, for example, stress caused by external pressure such as press pressure at the time of lamination processing manufacture or strong wind after installation. And keep flat shape withstand temperature change. As a result, the power generation cell assembly 4 is protected from damage in a stable state. At the same time, an iron plate was used for the module substrate, so the coefficient of linear expansion was (12.1 × 10 minus 6th power / ° C), which is closest to that of the silicon power generation cell (2.7 × 10 minus 6th power / ° C). It has characteristics, and it is possible to minimize the occurrence of stress that damages the power generation cell and the power generation cell assembly 4 due to temperature changes during manufacturing and use.

The stress is aluminum plate on the module substrate (linear expansion coefficient is 24 × 10 minus 6 / ° C)
Much smaller than copper or copper plate (16.5 × 10 minus 6th power / ° C) or austenitic stainless steel with chromium and nickel components (16.5 × 10 minus 6th power / ° C). In addition, the expansion stress due to the temperature change on the power generation cell can be halved. Ferrite or martensitic stainless steel plate with a low coefficient of linear expansion as the component (10.0 x 10 minus 6th power / ° C) is used as the module substrate. It has the effect of protecting. However, in terms of cost, it is not suitable for the structure system of claim 1, but is suitable for the system of claim 4 in which the cooling medium 11 is in direct contact.

  As important as the selection of the material of the module substrate 8 as described above, the selection of the thickness of the metal plate to be used is important. As presented in claim 1, the cooling medium pipe cover of FIG. 1 is formed by molding an aluminum plate having a thickness of 0.3 mm. The module board uses a 1.0mm thick galvanized iron plate, so it has enough strength compared to the 0.3mm thick aluminum plate cooling medium duct cover, and the temperature change Even if there is a force that deforms from the outside (for example, pressure and thermal strain during lamination, wind pressure after installation, etc.), the flatness is always maintained, and the power cell assembly 4 can be protected. is there.

FIG. 2 is different from FIG. 1 in that the cooling medium conduit 10 made of copper pipe is formed by using the metal band 23 presented in claims 2 and 3 in order to make the connection between the module substrate 8 and the coolant conduit 10 more reliable. Are fixed to the module substrate 8 made of galvanized iron plate by spot welding. The metal band 23 uses a galvanized iron plate having a width of 10 mm, a length of 50 mm, and a plate pressure of 0.3 mm. The metal band 23 fixes the main part of the cooling medium pipe 10 and does not fix the whole. Since a thin plate of 0.3 mm may be used, there is no problem in maintaining the flatness and strength of the entire substrate because the heat deformation of the module substrate by welding is limited to a minute amount.

Lamination bonding of the entire module is performed by stacking the members shown in FIG. 2 as shown in the figure and heating to 150 degrees to melt the bonding resins A, B, and C in a vacuum state. At this time, the bonding resin C is a single film, and the cooling medium pipe cover 13 is covered with the EVA film 0.6t as the bonding resin C film, and the cooling medium pipe 10 is placed thereon. A module substrate and other members are stacked on top of each other. In this state, the bonding resin C is melted by applying a vacuum state by applying a vacuum state as shown in the figure, and the bonding resin C is dissolved between the cooling medium conduit 10 and the module substrate 8 as shown in FIG. Invade and join together. The aluminum block spacer has a function of transferring heat from below while applying a surface pressure to the flat surface of the cooling medium duct cover.

FIG. 3 shows details of the aluminum cooling medium pipe cover 13 used in FIGS. 1 and 2. The cover 13 is divided into 12 pieces as shown by the dividing line 16 in the figure, and these are temporarily joined together with an aluminum foil adhesive tape 24 so as to be combined as if they were not divided. The cover is formed so that the cooling medium pipe line 10 can be fitted into the cooling medium pipe cover pipe part 14. Finally, both are joined in a combined state as shown in FIGS. At that time, both share the upper flat surface 17 and are joined to the flat module substrate by the flat surfaces.
The cover 13 is formed by molding a thin aluminum plate of 0.3 mm, and its function is such that the cooling medium pipe 10 is mechanically and thermally bonded to the module substrate 8 by combination with the bonding force of the bonding resin C12. Furthermore, it has a function of efficiently transmitting the heat generated in the power generation cell to the cooling medium pipe line by utilizing heat conduction in the aluminum plate.

Although this aluminum plate is thin, the material has a large coefficient of thermal expansion, so stress is generated between the module substrate due to temperature changes, warping and deformation of the module substrate, and peeling of the joint due to the bonding resin C. There is a worry to come. Therefore, the thickness of the aluminum plate is made as thin as 0.3 mm, and is divided into 12 pieces as shown in FIG. 3, so that the expansion and contraction strain in the aluminum plate is absorbed by the division.

  FIG. 4 shows a solar cogeneration module of a type in which the cooling medium pipe 10 is formed by bonding two stainless plates. The upper stainless plate constitutes a flat module substrate 8, and the lower stainless plate is the cooling medium passage plate 22. Both stainless steel plates are ferritic stainless steel with a small coefficient of linear expansion. Further, the module substrate 8 has a thickness of 1.0 mm and that of the cooling medium passage plate is 0.4 mm. Thus, the expansion and contraction of the module substrate due to the temperature change is relatively small, and deformation due to stress with the cooling medium passage plate is small, so that the module substrate maintains its flatness and deformation is small. As a result, the power generation cell assembly 4 is sufficiently protected from damage on the solid flat plate.

A silicon sealing material is applied to the periphery of the light receiving output portion 9 of the module substrate 8 and covered with a seal cover 26. This prevents the entry of humidity components and the like from the end face into the joint portion, and increases the reliability of the members of the light receiving output portion 9 and the joint.
In the above, the Example of the solar cogeneration module using the light reception output part 9 of two types of structures was described.
In any case, a metal band 23, a cooling medium pipe cover, or a cooling medium passage plate as a metal member to be welded or joined to a thick module substrate is used. The technology of ensuring the strength and stability (flatness) by reducing the thickness of the board to be thinner than the module board and reducing the influence on the module board.

  With the above effects, it is possible to produce a solar cogeneration module with high performance and long life reliability exceeding 20 years at a practical cost.

FIG. 1 is a central sectional view of the present invention case 1 of a solar cogeneration module. FIG. 2 is an explanatory view of lamination joining of the module. FIG. 3 shows a cooling medium pipe and a cooling medium pipe cover according to the present invention. FIG. 4 is a cross-sectional view of Case 2 of the solar cogeneration module of the present invention.

DESCRIPTION OF SYMBOLS 1 Module upper surface cover glass 2 Upper heat insulation layer 3 Cell upper surface cover 4 Power generation cell assembly 5 Power generation cell connector wire 6 Resin A for joining
7 Resin B for bonding
8 Module board 10 Cooling medium conduit 11 Cooling medium 12 Resin C for bonding
13 Cooling medium duct cover 14 Cooling medium duct cover duct section 15 Aluminum block spacer 16 Split line 17 Upper flat surface 18 Resin C for bonding
20 Module frame 21 Lower heat insulating layer 22 Cooling medium passage plate 23 Metal band 24 Aluminum foil adhesive tape 25 Welded joint

Claims (8)

A solar cogeneration module that receives sunlight and outputs electric power and heat on its upper surface, and has a flat or film-like cell upper surface cover made of resin or glass that is transparent to sunlight on its upper surface, and a flat plate below it Assembling a power generation cell, a module substrate made of a flat metal plate underneath, a cooling medium conduit bent and shaped by meandering a metal conduit on a plane below it, and the cooling medium conduit underneath it Cooling medium duct cover for fixing in contact with the module board made of the product, a solar cogeneration module that incorporates a plate-shaped light receiving output section that is constructed by sequentially superimposing these and joining them with a thermoresponsive resin In
A solar cogeneration module characterized in that a metal plate having a thickness smaller than that of the module substrate is used as the cooling medium duct cover. A solar cogeneration module that receives sunlight and outputs electric power and heat on its upper surface, and has a flat or film-like cell upper surface cover made of resin or glass that is transparent to sunlight on its upper surface, and a flat plate below it Assembling a power generation cell, a module substrate made of a flat metal plate underneath, a cooling medium conduit bent and shaped by meandering a metal conduit on a plane below it, and the cooling medium conduit underneath it Cooling medium duct cover for fixing in contact with the module board made of the product, a solar cogeneration module that incorporates a plate-shaped light receiving output section that is constructed by sequentially superimposing these and joining them with a thermoresponsive resin In
A part of the cooling medium pipe line is fixed on the module substrate by welding a metal band onto the module substrate, and the cooling medium is fixed to the module substrate by both general welding and joining with the above-described heat-responsive resin. A solar cogeneration module characterized by joining pipes.   The solar cogeneration module according to claim 2, wherein a metal band having a thickness smaller than a thickness of the module substrate is used as the metal band. Stainless steel metal plate press-molded to form a cooling medium flow path on the lower surface of the module board instead of the metallic cooling medium pipe and the cooling medium pipe cover, using a stainless steel plate for the module board. In the solar cogeneration module according to claim 1, wherein the cooling medium passage plate made of a plate is welded and the cooling medium flow path is formed therebetween.
A solar cogeneration module using a metal plate having a thickness smaller than that of the metal plate of the module substrate as the cooling medium passage plate. The iron plate or the steel plate, the iron plate or the steel plate plated with the surface, and the ferritic or martensitic stainless steel plate are used as the module substrate. Solar cogeneration module. 6. The solar cogeneration module according to claim 1, wherein single crystal or polycrystalline silicon is used as the power generation cell. 2. A coating resin for a caulking seal is applied to cover the outer peripheral end surface of the light receiving output portion using an iron plate or a steel plate plated iron plate or a plated steel plate on the module substrate. The solar cogeneration module according to any one of the above. 2. The cooling medium pipe cover made of an aluminum plate, wherein the formed intermittent cut lines or cut and raised bead lines or a combination of at least four divided cut lines is used. The solar cogeneration module according to any one of 2, 3 and 4.