WO2011158147A1

WO2011158147A1 - System and method for laminating pv device

Info

Publication number: WO2011158147A1
Application number: PCT/IB2011/052350
Authority: WO
Inventors: Donat Brian
Original assignee: 3S Swiss Solar Systems Ag
Priority date: 2010-06-17
Filing date: 2011-05-29
Publication date: 2011-12-22

Abstract

Disclosed are methods and system for laminating at least a solar module The method comprises the steps of making at least a lay-up of a solar module, removing air from inside of the lay-up, and sealing the lay-up, wherein vacuum is retained inside the lay-up. The system comprises means for removing air from inside of a lay-up, means for applying a sealing on at least a first layer of the lay-up, and means for pressing the lay-up together to form a sealed cavity for keeping out the air, wherein at least a base is capable of retaining at least the first layer of the lay-up

Description

SYSTEM AND METHOD FOR LAMINATING PV DEVICE

FIELD OF THE INVENTION

The present invention relates generally to laminating of solar modules, and, more particularly to system and methods for lamination of photovoltaic device (PV-device) in a robust, cost effective, secure, and environmental friendly manner.

BACKGROUND OF THE INVENTION

Generally, in the manufacturing of solar panels, a solar module is set up normally at normal room conditions. The solar module is generally built up out of a sandwich structure of material layers, called lay-up, wherein solar cells embedded between the material layers. The lay-up comprises a glass plate as a substrate, a first layer of plastic film (adhesive foil) laid on the glass plate, solar cells, and a second layer of plastic film, on which a cover film is laid. The solar cells are embedded between the first and the second layer of plastic films (adhesive foils), for example, EVA film. The cover film, also called 'back sheet' can form a weather resistant layer. Instead of the back sheet, a second glass plate can be applied. In some special applications (usually called thin film modules) the cells will be outlined directly on the substrate/superstrate glass. In this case, the layer of plastic film will be between the substrate/superstrate glass and the back sheet or the back/front glass. When the lay-up is constructed, it will be processed in a laminator (lamination process). The laminator incorporates typically a lower part with a hot plate and an upper portion with a vacuum chamber, which is divided in two parts i.e., an upper chamber and a lower chamber by a membrane. This two chamber principle serves for two functionalities: first, it will remove air from the lay-up, second, by applying ambient air to the upper chamber, the membrane creates pressure to the lay-up.

During the lamination of a solar module, an interconnecting process takes place under the influence of heat, vacuum and pressure in which the solar cells are finally encapsulated between the covering glass plate and the back sheet. For the encapsulation of photovoltaic modules (PV- modules) one of the lay-up-concepts is, to pack the photovoltaic (PV) sensitive layers between two sheets of glass. This is used in particular for thin film layers, which are highly sensitive to moisture and therefore need to be sealed for protection against humidity to prevent corrosion of layers. Glass sheets are preferred over plastic layers, because the plastic layers are not very well suited to keep the humidity out.

The prior art discloses numerous techniques for laminating sandwiched bodies i.e., lay-up of solar modules or photovoltaic modules (also known as PV Module). According to the WIPO patent publication number WO2003050891, the sandwich or layer structure so formed is heated to a temperature suitably of about 140° C to about 160° C, that will soften the encapsulant materials, and the entire assembly is pressed together at the elevated temperature, optionally in a vacuum chamber to preclude the formation of air pockets of bubbles between the substrates, and to form the sealed module. Here the module is heated and then pressed together. As crystalline cells, used normally, have a certain thickness: silicon, bus bars, ribbons etc. When the module is pressed together before the materials are melted, cell breakage may increase because pressure is not applied homogeneously, e.g. the bus bars are pressed in to the silicon.

According to US patent publication number 1508289682, the module comprises a butyl rubber adhesive containing silane primer, wherein the adhesive is between at least the front layer and the foil covering the edge of the front layer. It is stated that the manufacturing may include steps 'such as vacuum lamination or other types of lamination' . However, the publication fails to disclose first pressing together (not laminating) the lay-up under vacuum. Also the butyl containing substance is used as encapsulant not as seal around the circumference.

According to the Japanese patent publication number JP 1508147382, a solar cell panel includes a solar cell element sealed in a protective material and a first seal member which surrounds the protective member. In this case, the first seal member is constituted of a material having small water vapour permeating property or polyisobutylene rubber. Further, a material prominent in shock resistance or a second seal member consisting of butyl rubber is interposed between the terminal unit of the solar cell panel and a recess of a frame, into which the terminal unit is inserted. Here, the problem really lies in heating and evacuating at the same time. When the adhesive layer is heated, gasses e.g. peroxide are set free. This is needed for the curing to take place. When during heat-up the evacuation process is still commencing, a lot of peroxide is removed that makes the curing process slower. Experiments have shown that the loss of additives resulted in longer processing times i.e. the curing takes longer due to the missing effect of the peroxides, and lower quality i.e. loss of adhesion due to loss of primer. Also, the exhausted peroxides are dangerous for the environment, humans and damage the equipment, which need to be eliminated. The existing laminating means fail to address this problem.

Further, according to the conventional laminating means if the module was laminated before it is moved to the next stage, the vacuum created for lamination no longer exists on a macroscopic level, because all macroscopic cavities holding the vacuum would have been filled with the melted adhesive used. Unfortunately, very small, microscopic cavities may still exist and hold a vacuum.

The features of the conventional laminating systems disclose a complex design and bulky structural indices that hinder their performance. However, no such system and/or method is available in the commercial market at the present time which is capable of reducing the process cycle times by factors for reducing the production costs of PV-modules substantially and helps to reach grid parity. Further, the conventional laminating system and methods also fail to control the process parameters, e.g. values, duration and ramps of temperatures, and pressures more independently.

Therefore, the present scenario is necessitating the need for an improved combination of convenience and utility which is capable of overcoming disadvantages inherent in existing solar module or lay-up laminating systems and providing means for: reducing the process cycle times by factors for reducing the production costs of PV-modules substantially and helps to reach grid parity and controlling the process parameters more independently.

SUMMARY OF THE INVENTION

In view of the foregoing disadvantages inherent in the prior arts, the general purpose of the present invention is to provide an improved combination of convenience and utility, to include the advantages of the prior art, and to overcome the drawbacks inherent in the prior art. The present invention incorporating within it simple structural indices for a simple, cost effective, secure, reliable, and environment friendly operation. In one aspect, the present invention provides a lamination method for robust and high volume manufacturing or lamination of PV- device, such as glass-glass module and a thin-film module. The method of the present invention is capable of reducing the production costs of thin-film PV- modules considerably and therefore helps to reach grid parity, i.e., price for 1 kWh produced with PV equals to price for 1 kWh of power coming from the grid, probably originating from coal or gas burning power plants, nuclear power or other non-sustainable energy sources.

In another aspect, the lamination method of the present invention is capable of reducing the process cycle times by factors compared to the times currently required by the conventional laminating processes or methods, therefore the present invention is capable of increasing the manufacturing throughput. Also the complexity of the devices needed for the lamination may be reduced. Additionally, the process reliability and stability may be improved, which results in a high yield. Further, as the throughput per manufacturing line is higher, less parallel processing units are required, which ends in less investment costs, i.e., reduced CAPEX, and a smaller foot print i.e., space needed for the machines.

In another aspect, the present invention provides a method for laminating the solar module. The method comprises the steps of: making at least a lay-up of a photovoltaic module; removing air from inside of the lay-up; and sealing the lay-up so that no air comes in, e.g. by pressing the lay-up together. After pressing no air can enter into the lay-up. A sealant may be applied to the lay-up to seal the lay-up. The vacuum may be retained inside the lay-up to prevent bubbles or formation of cavities or entrapment of air inside the lay-up. The solar module also referred to as 'photovoltaic module' or 'module' or 'lay-up' or 'laminate'.

In yet another aspect, the present invention provides a method for laminating PV modules. The method includes the steps of vacuumising the lay-up; heating-up the lay-up; maintaining temperature of the lay-up; and cooling down the lay-up. During the, maintaining of the temperature and cooling down, pressure may be applied. As the materials inside the module cure, gasses such as peroxide or C0₂ are set free. The invention is capable of preventing atleast formation of the bubbles and separation of layers of the module by applying external pressure.

In yet another aspect, the present invention provides an inventive process for laminating the lay- up. The inventive process may be divided into a plurality of separate stages including: making at least the lay-up of a photovoltaic module, removing air from the lay up, pressing the lay-up together without heat, pressing and curing the lay-up, pressing and cooling the lay-up.

In yet another aspect, the present invention provides a system for laminating a PV-module. The system comprises: at least a base capable of retaining at least a first layer of a lay-up; means for applying a sealing on the first layer of the lay-up; means for removing air from the lay-up; and means for pressing the lay-up together to form a sealed cavity for keeping out the air.

In yet another aspect, a system for laminating a PV-module, comprises: means for removing air from inside of a lay-up; means for pressing the lay-up together; means for heating the lay-up; and means for cooling down the lay-up. A sealant is applied to the lay-up to seal the lay-up and then transport the lay-up to a next stage. The vacuum is retained inside the solar module and the lay-up is held together by pressing the lay-up.

In another aspect of the present invention, the vacuum extends in the space between the materials of the lay-up and thus extends of substantially over the complete area of the lay-up within the confinements of the sealing.

These together with other objects of the invention, along with the various features of novelty that characterize the invention, are pointed out with particularity in the claims annexed hereto and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the nature of the present invention, reference should be made in the detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1A illustrate an exploded view of a PV module, according to an exemplary embodiment of the present invention; FIG. IB illustrate a thin Film PV- module with an active side of a cell away from a glass (substrate), according to an exemplary embodiment of the present invention;

FIG. 1C illustrate a PV- module with an active side of the cell is on the glass (supers trate), according to an exemplary embodiment of the present invention;

FIG. 2A illustrates a lay-up with conventional crystalline cells, according to an exemplary embodiment of the present invention;

FIG. 2B is illustrates the lay up wherein a thin film applied to a front layer, according to an exemplary embodiment of the present invention;

FIG. 2C is illustrates the lay up wherein a thin film applied to a back layer, according to an exemplary embodiment of the present invention;

FIG. 3 illustrates a method for laminating PV- module, according to an exemplary embodiment of the present invention;

FIG. 3A illustrates a time-temperature-vacuum-pressure graph, according to an exemplary embodiment of the present invention;

FIG. 4 illustrates a method for laminating PV- module, according to an exemplary embodiment of the present invention;

FIG. 5 illustrates an inventive process for laminating the lay-up, according to an exemplary embodiment of the present invention;

FIGS. 6A and 6B illustrate a build-up of an edge sealant, according to an exemplary embodiment of the present invention;

FIGS. 7 A and 7B illustrate deformable sealing of the vacuum chamber, according to an exemplary embodiment of the present invention; FIG. 8 illustrates controlling the heat-up, according to an exemplary embodiment of the present invention;

FIG. 9 shows a vacuum chamber with a cover and a base wherein the space between the base and a lid has not evacuated or an evacuation has not yet completed, according to an exemplary embodiment of the present invention;

FIG. 10 shows a glass plate sucked against the cover, deforming a sealing, wherein the space between the lid and the base plate is evacuated, according to an exemplary embodiment of the present invention;

FIG. 11 shows a closed but not evacuated vacuum chamber, according to an exemplary embodiment of the present invention;

FIGS. 12 and 13 illustrate a closed but not yet evacuated vacuum chamber with a different types of sealing, according to an exemplary embodiment of the present invention;

FIG. 14 shows one type of sealing that neatly folds when the cover is lower, thus reducing stress on the sealing, according to an exemplary embodiment of the present invention;

FIGS. 15 and 16 shows a plan view of a conveyor belt wherein a lay-up is placed on a transport sheet to move the lay-up into the vacuum chamber, according to an exemplary embodiment of the present invention;

FIGS. 17A and 17B illustrate a system for laminating PV- module, according to an exemplary embodiment of the present invention; and

FIG. 18 illustrates a system for laminating the PV- module, according to an exemplary embodiment of the present invention.

Like reference numerals refer to like parts throughout the several views of the drawings. DETAILED DESCRIPTION OF THE INVENTION

The exemplary embodiments described herein detail for illustrative purposes are subject to many variations and structure and design. It should be emphasized, however that the present invention is not limited to a particular system and methods for laminating sandwiched bodies/structures or lay- ups or PV-modules, PV-device as shown and described. Rather, the principles of the present invention can be used with a variety of lamination configurations and structural arrangements. It is understood that various omissions, substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but the present invention is intended to cover the application or implementation without departing from the spirit or scope of it's claims.

In the following detail description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these specific details.

As used herein, the terms 'a', 'an', 'at least' do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item, and the term 'a plurality' denotes the presence of more than one referenced items. The term 'PV device' includes atleast any one of an individual wavers, solar cells, strings, matrices, modules or any combination thereof.

According to an exemplary embodiment, the present invention provides an improved system and methods for robust and high volume manufacturing or lamination of PV-modules including a glass-glass module and a thin- film module. The method of the present invention is capable of reducing the production costs of thin-film PV-modules considerably and therefore helps to reach grid parity, i.e., price for 1 kWh produced with PV equals to price for 1 kWh of power coming from the grid, probably originating from coal or gas burning power plants, nuclear power or other non-sustainable energy sources.

The present invention is capable of reducing the process cycle times by factors compared to the times currently required by the conventional laminating processes or methods, therefore the present invention is capable of increasing the manufacturing throughput. Also the complexity of the devices needed for the lamination may be reduced. Additionally, the process reliability and stability may be improved, which results in a high yield. Further, as the throughput per manufacturing line is higher, less parallel processing units are required, which ends in less investment costs, i.e., reduced CAPEX, and a smaller foot print i.e., space needed for the machines.

The present invention is also capable of controlling the process parameters more independently. The process parameters include values, duration and ramps of temperatures, and pressures.

The system for laminating PV-modules of the present invention, may be mass produced inexpensively and provides user a robust, easy, efficient, secure, cost effective, environment friendly and productive way of lamination.

Referring to FIG. 1A which illustrate an exploded view of a PV module 10 (), according to an exemplary embodiment of the present invention. The PV module 10 comprises a surface glass 17 (also referred to as 'front glass'), an encapsulant material 15, a sealant 90, a PV- sensitive layer 22. The PV- sensitive layer 22 placed on a glass substrate 19 (also referred to as 'back glass'). The lay- up 10 may be made by applying the encapsulant by means of at least any one of a cutted foil, a coating, or any combination thereof. The lay-up 10 may be constructed manually. The sealant 90 (also referred to as 'edge sealant') may be layed-up by means of robots which is capable of placing the edge sealant 90 in forms of tapes, a cutted foil or by extruding. The edge sealant 90 may be applied in a high viscose form by spraying, coating, sputtering or the like. The sealant 90 may be applied to the lay-up 10 to seal the lay-up 10 and then transport the lay-up 10 to the next stage.

Referring to FIG. IB which illustrates a monolithic-TF-GG Substrate 10a, according to an exemplary embodiment of the present invention. The monolithic-TF-GG Substrate 10a, comprises a front glass 17a, a substrate glass 19a, the sealant 90, and a solar cell 20 (also referred to as 'cell'). The active side of the cell 20 may be looking away from the substrate glass 19a. The active layer 20 is highly sensitive to moisture and the sealing such as sealant 90 is capable of protecting the active layer 20 from the moisture.

Referring to FIG. 1C which illustrates a monolithic-TF-GG Superstrate 10b, according to an exemplary embodiment of the present invention. The monolithic-TF-GG Superstrate 10b, comprises a superstrate glass 17b, a back glass 19b, the sealant 90, and the solar cell 20. The active side of the cell 20 may be on the superstrate glass 17b. Thin film PV modules 10b and 10a may differ from conventional crystalline modules 10c (FIG. 2A) in that the solar cell 20 is manufactured on the glass substrate 19. The cell 20 is too thin, i.e., thickness of some microns only, to be handled without this carrier, i.e., without the glass substrate 19. In the PV module 10, the glass 17, 17a or 17b may form the transparent cover.

Referring to FIG. 2A, 2B, and 2C together, wherein FIG. 2A illustrates a lay-up 10c with conventional crystalline cells 22 (also referred to as 'crystalline cells'), FIG. 2B illustrates a lay-up lOd wherein a thin film 24 may be applied to the front layer 17, and FIG. 2C illustrates the lay-up lOe wherein a thin film 24 may be applied to the back layer 19, according to an exemplary embodiment of the present invention. The lay-ups 10c, lOd and lOe may have a front layer 17, a back layer 19, active layers 22 and 24, an adhesive layer 15, and a sealant 90. At least any one of the front layer 17 and the back layer 19 may be made of a glass, ceramics or a plastic material. At least a sunny side of the modules 10a, 10b, 10c, lOd, and lOe may be transparent. The active layer 20 may include all kinds of solar cells including crystalline solar cells 22, thin film 24, hetero junction, etc. Properties of multiple layers may be joined in one, for example, the active layer 20 may already be applied to the front layer 17 or the back layer 19. Also the back layer 19 may have adhesive properties.

The adhesive layer 15, also known as encapsulant, may be a sheet of EVA, TPU, PVB, Silicon, etc. The sealant 90 may be applied to the lay-ups 10, 10a, 10b, 10c, lOe and lOd to seal the lay-ups 10, 10a, 10b, 10c, and lOd, lOe and then transport the lay-up 10, 10a, 10b, 10c, and lOd lOe to a next stage. The sealant 90 may be laid on at least any one of the front layer 17, the back layer 19, the active layer 20, adhesive layer 15 or any combination thereof. The sealant 90 may also overlap atleast any one of the adhesive layer 15, the active layer 20, or any combination thereof. The sealant 90 may be a butyl or the like.

Referring to FIG. 3, which illustrates a method 100 for laminating PV-modules, according to an exemplary embodiment of the present invention. The method 100 comprises the steps of: making atleast a lay-up 10 of a photovoltaic module (also referred to as 'solar module' or 'module') at a step 110; removing air from inside of the lay-up 10 at a step 120; and sealing the lay-up as to remain the vacuum in the lay-up 10 at a step 130. A sealant 90 may be applied to the lay-up 10 to seal the lay-up 10. The vacuum may be retained inside the lay-up 10 to prevent bubbles or formation of cavities or entrapment of air inside the lay-up 10. The lay-up 10 includes the monolithic-TF-GG Substrate lay-up 10a, the monolithic-TF-GG Superstrate lay-up 10b, the crystalline cell lay-up 10c, and the thin film lay-ups lOd, and lOe.

In an exemplary embodiment, the present invention provides means for transporting the lay-up 10 or moving the lay-up 10 in and out of the vacuum chamber 40, in to the next stage or to a desired position. The desired position includes in and out of a vacuum chamber 40, into the next stage.

According to an exemplary embodiment of the present invention, after the step 120, the hermetically-sealed lay-uplO (also referred to as 'laminate') may keep the initially created vacuum inside the laminate 10. Now the lay-up 10 may be transported to the next step. This step may preferably be carried out in another machine, such that the lay-up 10 leaves the vacuum chamber 40 (as shown in FIGS 7A and 7B) before being processed further.

According to an exemplary embodiment of the present invention, additional lamination process may further include atleast a step of removing the lay-up 10 from the source of the vacuum and commencing to a second processing step before which the lay-up 10 may be exposed to a pressure larger than the vacuum, for example, ambient pressure.

According to an exemplary embodiment of the present invention, the air from inside the lay-up 10 may be removed in a vacuum chamber 40. The vacuum chamber 40 preferably is not much bigger than the lay-up 10 so that the volume of air that has to be removed from the vacuum chamber 40 is kept small. The vacuum chamber 40 consisting of a plurality of parts that are movable towards each other and a sealing 90 that seals the vacuum chamber 40 in a first and a second relative position, wherein in the first position an additional layer being at a distance from the lay-up 10 and in the second position the additional layer being part of the lay-up 10.

A vacuum bag may also be used to remove the air from inside the lay-up 10. The air may also drawn out thru a valve. The valve may remain part of the lay-up 10 or may be removed. The air may still be removed in a vacuum chamber 40 because the sealant 90 may not yet pressed against the layers it abuts, leaving opening for the air the flow out thru. According to an exemplary embodiment of the present invention, the air from inside the lay-up 10 may be removed by evacuation or by substituting the air by a gas that may be absorbed, for example, by the adhesive layer 15, during lamination. The lay-up 10 is put in a vacuum chamber 40. Alternatively, the lay-up 10 may be put in an atmosphere of gasses that do not hinder further processing, for example, the lay-up 10 may be swamped in CO₂ that may be absorbed by say the adhesive layers 15 during lamination. This gas is pressed into the EVA-Layer used as adhesive. Typically the adhesive layers 15 may absorb huge amounts of CO₂.

According to an exemplary embodiment of the present invention, the lay-up 10 may be pressed together so that the lay-up 10 may be held together and the vacuum may be retained inside the lay- up 10. Pressing the lay-up 10 together may be carried out by a pressure difference over the front layer 17 and the back layer 15 of the lay-up 10. An additional press may be used to press the lay- up 10.

Once the lay-up 10 is completely sealed, then a heating phase may be commenced to heat the lay- up 10. The heating of the lay-up 10 may take place in the same vacuum chamber 40 or may be carried out in another device. During the heating phase, the adhesive layers 15 may be melted and cured. If required, an additional pressure may easily be supplied in the heating phase using the press. Since during curing gasses are formed that tend to delaminated the module, atleast the additional pressure may be counteracted. At the end of the heating phase, the lay-up 10 has reached a stable condition to be moved to cool down phase.

According to an exemplary embodiment of the present invention, after having pressed the lay-up 10 together, the adhesive layers 15 may still in its original state and may have not undergone significant changes such as curing.

According to an exemplary embodiment of the present invention, the lay-up 10 may be cooled down in a cooled down phase. If required, again additional pressure may be applied.

According to an exemplary embodiment of the present invention, the sealant 90 may be capable of preventing loss of additives from the encapsulation material i.e., from the adhesive layers 15. The sealant 90 may augments the characteristics of the encapsulant 15 and prevents the vacuum pump from being harmed by these aggressive gasses. The sealant 90 may benefit in the choice of the encapsulation material, as the sealant 90 may incorporate fewer additives and less of them, i.e., only the amount and sort really needed. No overdose may be needed to compensate the materials that are normally removed when creating the vacuum.

According to an exemplary embodiment of the present invention, the present invention is capable of eliminating the loss of additives which may resulted in longer processing times i.e. the curing takes longer due to the missing effect of the peroxides and lower quality i.e. loss of adhesion due to loss of primer. Also, the exhausted peroxides which are dangerous for the environment, humans and damage the equipment may also be eliminated with the present invention.

Referring to FIG. 3A which illustrates a time-temperature-vacuum-pressure graph, according to an exemplary embodiment of the present invention.

Now, referring to FIG. 4 which illustrates a method 200 for laminating PV- module, according to an exemplary embodiment of the present invention. The method 200 includes the steps of vacuumising the lay-up 10 at a step 210; heating-up the lay-up 10 at a step 220; maintaining temperature of the lay-up 10 at a step 230; and cooling down the lay-up 10 at a step 240. These steps, also known as process parameters, may be combined within one sole equipment depending on the individual machine concepts. These steps may have to be applied in an exact, safe and also timely well coordinated manner.

According to an exemplary embodiment of the present invention, during the vacuumising of the lay-up 10 at the step 210, firstly existing air in the inside of a lay-up 10 may be removed (vacuumised) or atleast partially replaced by a gas e.g. CO₂ or fluid or a material which may be absorbed or assimilated in the encapsulation material 15 during lamination or curing process, without generating other unintended future problems in the lay-up 10. The gas may be absorbed and the fluid binds with / sticks to other materials to form the module 10. The vacuumisation of the lay-up 10 is achieved before any accidentally reaction, for example, outgassing, of the encapsulant material takes place. The vacuum extends in the space between the materials of the lay-up 10 and thus extends of substantially over the complete area of the lay-up 10 within the confinements of the sealing or the sealant 90. The heat-up process is one of the most difficult one, as there are many different existing kinds of materials involved. Each of the materials has its one reaction and influence. According to an exemplary embodiment of the present invention, during the heating -up the lay-up 10 at the step 220, the temperature may be raised in the whole lay-up 10 (laminate) simultaneously and homogeneously, with negligible temperature differences between and inside the materials, to avoid any mechanical stress. In particularly, temperature differences are expected, as the temperature development inside the laminate 10 depends on the kind of temperature transmission. Also, a maximal temperature level may not to be exceeded, to avoid any unintended reaction of an influenced material. Additionally, a certain pressure may be required when temperature is raised in order to avoid any creation of bubbles, due to outgassing. In view of all these parameters and influences, a separation of this heat-up process from other's, i.e. vacuumisation, is crucial.

According to an exemplary embodiment of the present invention, the temperature of the lay-up 10 may be maintained at the step 230. As the required temperature exists already in the laminate 10 and during the step 230 the encapsulant material needs a certain dwell time for curing only, a simple and low-energy process may be adapted.

According to an exemplary embodiment of the present invention, the finished laminate or lay-up 10 may be cooled down during the step 240 to a room temperature. Again, the cooling down may be done similar to the heat-up process in simultaneously and homogeneous manner, with negligible temperature differences between and inside the materials, thus to avoid any mechanical stress.

Referring to FIG. 5, which illustrates an inventive process 300 for laminating the lay-up 10, according to an exemplary embodiment of the present invention. The inventive process 300 may be divided into a plurality of separate stages including: making atleast the lay-up 10 of a photovoltaic module at a step 310, sealing the lay-up 10 together without heat at a step 320, pressing and curing the lay-up 10 at a step 330, pressing and cooling the lay-up 10 at a step 340.

According to an exemplary embodiment of the present invention, the steps 310, 320, 330 and 340 may be individual stages which may be carried out in different process chambers. Some stages may be integrated in one chamber though. Multiple chambers may be part of one machine, e.g. to facilitate transport of the lay-up 10 from one chamber to the other or make multiple use of certain resources such as a vacuum pump or the framework to eliminate the need for alignment of adjacent steps.

In an embodiment, the steps 310, 320, 330 and 340 may be used in a stacked such that multiple levels may be used that are above each other to carry out the same process. This reduces foot print and facilitates the multiple use of certain resources.

According to an exemplary embodiment of the present invention, after the vacuum has been established and the lay-up 10 is still in the vacuum chamber 40, then the lay-up 10 may be pressed together preferably without applying additional heat.

According to an exemplary embodiment of the present invention, a pre -heating of the lay-up 10 may be adapted to heat the lay-up 10 as fast as one would like such that the temperature difference of the glass inner and outer surface may not exceed certain levels to prevent the warping of the glass 17, 19 and breakage or damaging of the active layer 20.

According to an exemplary embodiment of the present invention, the lay-up 10 may be heated before and during being evacuated. The temperatures may be remaining low, so that the encapsulant does not melt (too much) and the sealant 90 may leave vias 33 (as shown in FIG. 6A) open for the air to flow out thru.

According to an exemplary embodiment of the present invention, the lay-up 10 may not be heated before being pressed together. By heating the lay-up 10, the adhesive layers 15 of the lay-up 10 melt to flow and fill cavities in the lay-up 10 and the air may be removed from the lay-up 10.

According to an exemplary embodiment of the present invention, as the process of laminating the lay-up 10 may be a pipeline wherein the slowest step may determines a throughput. If the pressing and heating stage may be the slowest stage then a second such stage may be used to divide the time needed, thus speeding-up the whole chain.

According to an exemplary embodiment of the present invention, heating and cooling may be done in atleast a manner selected from: heating up by means of heating plates or heating press, heating up by means of IR-heater, heating up by hot air or oven, maintaining temperature by means of IR- heater, maintaining temperature by means of hot air or oven, cooling down by cooling plates, cooling fans, ambient air or any combination thereof.

According to an exemplary embodiment of the present invention, when the lay-up 10 is pressed together, basically the adhesive layer 15 alone may not retain the vacuum and primarily the sealant 90 keeps in the vacuum.

According to an exemplary embodiment of the present invention, in an optional step the temperature of the lay-up 10 may be kept within a certain temperature range. The range being such that the curing process may be completed. The temperature range may depend on the encapsulation material 15 being used. If needed, additional pressure may be supplied by atmospheric pressure or by the press.

According to an exemplary embodiment of the present invention, while the lay-up 10 is under pressure and has been heated to start and sustain the curing, the cooling may commence, thus profiting from the still applied pressure and speeding-up the process because the laminate has cooled already. Cooling means may be provided to cool the lay-up 10.

According to an exemplary embodiment of the present invention, materials, especially the glass plate may be heated before it is added to the lay-up 10. If this is done, no air may be present between the glass plate and the layer of the lay-up 10 it is placed on. Otherwise, the adhesive material may meld and stick to the glass and air may be trapped inside the lay-up 10 resulting in bubbles.

According to an exemplary embodiment of the present invention, in case if the glass is pre-heated to a degree that may make other materials melt, the front glass plate 17 and/or back glass plate 19 may be brought in contact with the lay-up 10 in the vacuum chamber 40 in order to preventing melting of the softer materials, thereby preventing deforming and trapping of air or bubble inside the lay-up 10.

According to an exemplary embodiment of the present invention, the back glass plate 19 with the thin film 20 on it may be pre-heated. The rest of the lay-up 10 is joined thereto under vacuum or placed in the vacuum chamber 40. Once the vacuum has been established to a desired degree, the pre -heated back glass plate 19 with thin film 20 on it may be lowered onto the rest of the lay-up 10.

According to an exemplary embodiment of the present invention, the sealing may be part of one of the layers in the lay-up 10, for example, the adhesive layer 15 or be of the same material. The sealing 90 preferably be sticky enough to seal the lay-up 10 without the lay-up 10 being heated. The sealant 90 alone may be heated to become sticky. This is fast since not the complete lay-up 10 may be heated and enables other materials to be used as sealant 90. Preferably the encapsulant 15 may be used now to seal the lay-up 10. The heating may be done by EM -radiation, probably laser, induction or ultrasonic sound.

Referring to FIGS 6A and 6B which illustrate a build-up of an edge sealant 90, according to an exemplary embodiment of the present invention. When the lay-up 10 is prepared, special attention to the application of the edge sealant 90 is required. The edge sealant 90 needs to be built up in such a manner, that it initially separates the glass sheets 17 and 19 and provides channels to let the air escape during evacuation. This may be achieved by applying the sealant 90 in such a way that vias 33 may extend from the interior of the lay-up 10 to the outside. The sealant 90 may be applied with elevations or may be separated in dashes. When pressing together the lay-up 10, the vias 33 may be closed.

If the lay-up 10 is placed in a vacuum chamber 40, air is evacuated from inside the lay-up 10 as well as around the lay-up 10. Meaning that no pressure difference is created of the lay-up 10 and the lay-up 10 is therefore not pressed together. Other means such as the press may have to ensure this. Alternatively the air may be let into the vacuum chamber 40 rapidly. Since the air has trouble flowing into the lay-up 10, a temporal pressure difference may occur, pressing the lay-up 10 together and closing the vias 33. This way the press may be omitted.

According to an exemplary embodiment of the present invention, the vacuum chamber 40 may be not much bigger than the lay-up 10 processed. This way as little as possible air may be evacuated, resulting in faster processing times. The same holds if a gas is used to remove the air from the lay- up 10. Inserts may be used to adapt the vacuum chamber 40 to the lay-up 40. Also the ambient pressure around the vacuum chamber 40 may be kept low. Whole machine i.e. system for laminating solar modules, may be is placed in a chamber with low pressure, so that the pressure difference is small and thus the amount of air that need to be evacuated is small. Alternatively, the materials may be fed into the vacuum chamber 40 from a low pressure chamber that has as low as possible pressure. In this way no time may be needed for evacuation at all. An adverse effect of leaking of the air may be prevented by keeping the pressure of the low pressure chamber lower than the pressure needed in the vacuum chamber 40. Further, a requirement of additional time to the production time of a module 10 may be avoided by creating the pressure in the lower pressure chamber during the processing in the vacuum chamber 40.

Referring to FIGS 7A and 7B which illustrate deformable sealing of the vacuum chamber 40, according to an exemplary embodiment of the present invention. The vacuum chamber 40 (also referred to as 'gas chamber') has to be closed before it may be evacuated (or swamped in C0₂). In an embodiment, the movement for closing the vacuum chamber 40 may also used to pressurise the lay-up 10. A cover 70 may be moved down as to close the vacuum chamber 40. The sealing 50 may be pressed down onto the base 60 to close the vacuum chamber 40 (FIG. 7A). Once the vacuum has been established, the cover 70 may be lowered further as to press on the lay-up 10 (FIG. 7B).

The sealing 50 may be compressed further and may be made in such a way that it may endure numerous of such cycles. The sealing 50 may be easily replicable because it may be damaged eventually.

In an embodiment, an advantage of the system of the present invention is that the cover 70 may only be movable in one direction and no further axes or pivoting joints may be needed.

Referring to FIG. 8 which illustrates controlling the heat-up, according to an exemplary embodiment of the present invention. To heat-up the lay-up 10 for curing of the encapsulant 15, the temperature may be applied symmetrically to avoid bending of the glass 17 or 19. This may be done by use of two heating plates 80. By adding a 'temperature transfer foil' 88, the temperature raise (gradient) may be controlled by means of type of material and thickness of the temperature transfer foil 88. Also, the material may be a kind of soft material to compensate unevenness of the laminate and the heating plates 80. The temperature transfer foil 88 may be transported with the lay-up 10 into the heating press, to absorb the temperature shock, which may be provided to the glass, when the high temperature difference from cold to hot may be applied. The same process applicable for cooling down.

According to an exemplary embodiment of the present invention, a symmetrical cooling down phase may be adapted to prevent the laminated or lay-up 10 from bending when cooling down. In the symmetrical cooling down phase isolation or even a mirroring layer may be provided to prevent the lay-up 10 from cooling from the side where it has no neighbour. The lay-up 10 may be placed in a carousel in such a way, that every lay-up 10 may has a neighbour. The heating may be provided to prevent the lay-up 10 from cooling from the side where it has no neighbour. A chamber with air circulating and surrounding the lay-up 10 with air of a homogenous temperature may be used.

According to an exemplary embodiment of the present invention, charging the lay-up 10 electrostatically may hold the lay-up 10 together. In this way, the sealant 90 may not have to be as sticky and the press may be needed to press the lay-up 10 together. An electrostatic charging device may be used though. Further, ideally the force applied by the charging is so large that the air is pressed out of the vacuum chamber 40, thus eliminating the need for a vacuum chamber 40. During heat- up the charged lay-up 10 may not delaminate due to gasses originating from the curing.

According to an exemplary embodiment of the present invention, spacers may be inserted in the lay-up 10 to guarantee a minimal distance and maximal pressure on the active layer 20.

In an exemplary embodiment, the present invention provides means for positioning an additional layer of the lay-up 10 onto the lay-up 10. The positioning means may be inside the vacuum chamber 40.

Referring to FIG. 9 which shows a vacuum chamber 40 with a cover 70, a base 7, and an attached sealing 42 in a recess of a lid, wherein the space between the base 7 and the lid has not been evacuated or an evacuation has not yet been completed, according to an exemplary embodiment of the present invention. Inside the cover 70, a suction plate 16 is shown with channels 44 (not shown) to create a vacuum between itself, a glass plate 2 and the sealing 42. In this way a glass plate 2 may be held against the upper inside of the cover 70. The seal 42 placed in recess advantageously compresses the lip. If the base plate 2 may be held against the lips and air may be removed, the base plate 2 may be pressed against the cover 70.

Referring to FIG. 10 which shows a glass plate sucked against the cover 70, deforming the sealing 42, wherein the space between the lid and the base plate 2 is evacuated, according to an exemplary embodiment of the present invention. The pressure between the suction plate 16, the glass plate 2 and the sealing 42 may to be lower than the pressure in the vacuum chamber 40 itself. Otherwise the glass plate 2 may fall down.

Referring to FIG. 11 which shows a closed but not evacuated vacuum chamber 40, according to an exemplary embodiment of the present invention. The vacuum chamber 40 may be sealed by means of the sealing 45. The glass plate 2 may still at a distance from the lay-up 6. The lay-up may in this case contain a glass plate, two layers of encapsulant with solar cells between them and a sealing around its perimeter for entrapping the vacuum when the glass plate 2 is lowered onto it under vacuum. Other lay-ups as previously described may be used as well. Now the vacuum may be created. Once this has been done, the cover 70 moves toward to base 7, pressing together the sealing 45 and lowering the glass plate 2 onto the lay-up 6. In the current invention now the lay-up 6 is pressed together and the vacuum is trapped inside the lay-up 6. The base plate 2 may be advantageously rigidly held by the cover 70. Here the vacuum chamber 40 closes when the cover 70 may move in the direction of the lower part 7. The vacuum may be created when the chamber 40 may be closed. Until the vacuum has been established, to the base plate 2 may not be in contact with the other layers 6, otherwise air may be trapped. If the desired vacuum has been reached, cover 70 may be lowered further into a second relative position and the base plate 2 and the other layers 6 may come into contact. The invention is not limited to these positions of the base plate 2 and the layers 6 or these materials.

It is an advantage of the present invention, that a seal 45 may be provided between the cover 70 and the lower part 7, which closes the vacuum chamber 40 during the evacuation, but as the cover 70 moves down may deform elastically without taking damage, even if this process may be repeated many times at high temperatures. The seal 45 may, for example, consist of a plastic or metal. In the first case, it may be designed to be inflatable. The pressure in the seal 45 may in that case for example when moving down the cover 70 may be kept constant. This ensures that a good seal may be present, with stressing the material of the seal too much. This type of sealing may be advantageous in embodiments where no pre-heating may be conducted as well.

Referring to FIGS. 12 and 13 which illustrate closed but not yet evacuated vacuum chamber 40 with a different types of sealing 45, according to an exemplary embodiment of the present invention.

Referring to FIG. 14 which shows one type of sealing 45 that neatly folds when the cover 70 is lower, thus reducing stress on the sealing 45, according to an exemplary embodiment of the present invention. Also a system may be conceivable, in which the shape of the seal 45 does not change greatly when moving down the cover 70, as shown for example in the FIGS. 12 and 13.

It may be advantageous if the seal 45 as in FIGS. 12, 13 and 14 may be mounted to the cover 70 so that it may not get dirty and the base plate 2 and the lower part 7 may be cleaned more easily. Ideally, the lower part 7 may be flat. In FIG. 14, the seal 45 may be formed as a tube and attached to the cover 70. The left part of FIG. 14 shows the device with a not yet lowered cover 70, while in the right part of FIG. 14, the device is shown with a lowered cover 70 and a compressed seal 45. Since the seal 45 may be a wear part, this may be easy to replace. The seal 45may be releasable attached to the cover 70, for instance by means of a snap connection.

Referring to FIGS. 15 and 16 which show plan views of a conveyor belt wherein a lay-up 6 is placed on a transport sheet to move the lay-up 6 into the vacuum chamber 40, according to an exemplary embodiment of the present invention. The transport sheet 2 extends under two resp. four sides of the sealing 45. If the layer structure 6 may be transported into the vacuum chamber 40 by means of a conveyor belt 48, the latter may depending on its design and width overlap the seal 45 on two (FIG. 15) or four (FIG. 16) sides. Furthermore, the conveyor belt 48 may include at least one depression, into which the materials of the layer structure 6 fit. Thus, the position of these materials or layers may be defined exactly. This allows e.g. to avoid or reduce the amount of materials protruding from the module 10. Also, markers may show where the materials have to be placed on the conveyor belt 48. The depression may support the sealing of the vacuum chamber 40. Referring to FIGS. 17A and 17B which illustrate a system 400 for producing PV-module, according to an exemplary embodiment of the present invention. The system 400 may comprises means for removing air 410 of atleast a lay-up 10, means for applying a sealing 490, and the lay-up 10 pressing means 420. The system 400 may further comprises the curing means 460 and cooling means 440 for the lay-up 10.

Referring to FIG. 18 which illustrates a system 500 for laminating a PV-module 10, according to an exemplary embodiment of the present invention. The system 500 comprises: atleast a base 570 capable of retaining atleast a first layer of the lay-up 10, means for vacuumising and sealing the lay-up 550, means for removing air 510 from the lay-up 10; and means for applying a sealing 590 to atleast a layer of the lay-up 10.

The system 500 further comprises: means for heating the lay-up 10; and means for cooling down the lay-up 10. A sealant 90 may be applied to the lay-up 10 to seal the lay-up 10 and then transport the lay-up 10 to a next stage while keeping air out of the lay-up. The vacuum is retained inside the lay-up 10 and the lay-up 10 is held together by pressing the lay-up 10. The lay-up 10 may be filled with gas for removing the air. The lay-up 10 may also be pressed together by ambient pressure.

Although a particular exemplary embodiment of the invention has been disclosed in detail for illustrative purposes, it will be recognized to those skilled in the art that variations or modifications of the disclosed invention, including the rearrangement in the configurations of the parts, changes in sizes and dimensions, variances in terms of shape may be possible. Accordingly, the invention is intended to embrace all such alternatives, modifications and variations as may fall within the spirit and scope of the present invention.

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions, substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but is intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.

Claims

CLAIMS We Claim:

1. A method for laminating at least a solar module, comprising the steps of:

making at least a lay-up of a solar module;

removing air from inside of the lay-up; and

sealing the lay-up,

wherein vacuum is retained inside the lay-up.

2. The method according to claim 1, further comprising steps of heating the lay-up and cooling down the lay-up.

3. The method according to previous claims, wherein additional pressure is applied on the lay-up according to the requirement.

4. The method according to previous claims, wherein the sealant is laid on atleast any one of a front layer, a back layer, an active layer, an adhesive layer or any combination thereof.

5. The method according to previous claims, wherein the air from the lay-up is removed through atleast any one of a vacuum chamber, a vacuum bag, a valve or any combination thereof.

6. The method according to previous claims, wherein the air is removed from the lay-up and atleast partially replaced by a gas or fluid.

7. The method according to previous claims, further comprising the steps of:

removing the lay-up from the source of the vacuum; and

commencing to a second processing step before which the lay-up is exposed to a pressure larger than the vacuum.

8. The method according to previous claims, wherein after the vacuum has been established and the lay-up is still in the vacuum chamber, the lay-up is pressed together without applying additional heat.

9. The method according to previous claims, wherein the lay-up is heated before and during evacuation.

10. The method according to previous claims, wherein the lay-up is not heated before being pressed together.

11. The method according to previous claims, wherein the heat is applied by atleast any one of a heating plate, a heating press, an IR-heater, an oven, a hot air or any combination thereof.

12. The method according to previous claims, wherein temperature is maintained by means of atleast any one of the IR-heater, the hot air, the oven or any combination thereof.

13. The method according to previous claims, wherein cooling down is conducted by atleast any one of cooling plates, cooling fans, ambient air or any combination thereof.

14. The method according to previous claims, wherein an encapsulant is applied by means of any of a cutted foil, a coating or any combination thereof.

15. The method according to previous claims, wherein the edge sealant is layed-up in atleast a forms of tapes, the cutted foil, by extruding or any combination thereof.

16. The method according to previous claims, wherein the edge sealant is applied in a high viscose form by atleast any one of a spraying, a coating, a sputtering or any combination thereof.

17. The method according to previous claims, wherein an additional pressure is supplied according to a requirement by atleast any one of an atmospheric pressure, a press or any combination thereof.

18. The method according to previous claims, wherein atleast any one of a glass plate, a thin film or any combination thereof is pre-heated and the rest of the lay-up is joined thereto under vacuum.

19. A system for laminating a photovoltaic module, comprising:

means for removing air from inside of a lay-up;

means for applying a sealing on atleast a first layer of the lay-up; and

means for pressing the lay-up together to form a sealed cavity for keeping out the air, wherein atleast a base is capable of retaining atleast the first layer of the lay-up.

20. The system according to claim 19, further comprises atleast any one of means for heating the lay-up, means for transporting the lay-up to a next stage, means for positioning an additional layer of the lay-up onto the lay-up or any combination thereof.

21. The system according to previous claims, further comprising a vacuum chamber, wherein the vacuum chamber consisting of a plurality of parts that are movable towards each other.

22. The system according to previous claims, wherein a sealing is adapted to seal the vacuum chamber in a first and a second relative position, wherein in the first position an additional layer is at a distance from the lay-up and in the second position the additional layer being part of the lay- up.