DE102009010351A1 - Connecting two plate-shaped workpieces with adhesive layer, useful for manufacturing photovoltaic module, comprising supplying first workpiece, placing adhesive layer and second workpiece on layer and hardening the above construction - Google Patents

Abstract

Connecting at least two plate-shaped workpieces with at least one heat-activatable and/or heat-curable adhesive layer, comprising: supplying a first plate-shaped workpiece to a continuous double-belt press; placing at least one layer of the adhesive; placing at least a second plate-shaped workpiece on the adhesive layer; activating and/or hardening the construction of at least two plate-shaped workpieces and at least one adhesive layer without the use of vacuum during the continuous pressing process in the double-belt press. An independent claim is also included for a continuous double-belt press, comprising two rotary pressing bands and an upper and a lower pressure pad for pressing a package structure containing a bottom plate-shaped workpiece, at least one heat reactivatable and/or heat curable adhesive layer and at least one overlying plate-shaped workpiece, where the occupancy of the package before the double-belt press running with a continuous feed rate is designed so that air bubbles remaining in the package during the press and the pressing operation is removed from the compound produced from the lower plate-shaped workpiece and the upper plate-shaped workpiece.

Description

background

The The present invention relates to a method for permanent bonding of at least two plate-shaped or arcuate Workpieces by means of a heat-activated and / or curable adhesive under pressure and heat.

The Invention is preferably used in the field of photovoltaic modules, which for long-term weather and weather resistance must be encapsulated water and moisture resistant. The inventive method described here and the corresponding device according to the invention can encapsulate both rigid photovoltaic modules, at which the active photovoltaic semiconductor layer with the corresponding electrical wires and contacts between two rigid glass panes Embedded lies (glass / glass modules), as well as rigid modules, at those on a glass carrier layer the corresponding active Photovoltaic layer is located and upwards through a weather resistant and moisture and vapor impermeable cover sheet film is covered (glass / foil module). Likewise, with the inventive method and the corresponding inventive Device flexible webs of photovoltaic modules used as a carrier layer and as a cover layer each have a film between which the corresponding embedded and encapsulated in active photovoltaic layers, be generated (flexible modules).

When Alternatively, the invention can also be used for the production of Laminated glass modules are used, consisting of two glass plates and an intermediate adhesive layer or a corresponding Multiple expansion according to the pattern glass / adhesive / glass / adhesive, etc. consist. The requirements for the production of this Laminated glass modules is approximately equal to the requirements for production of photovoltaic modules with the only difference being that no embedded active photovoltaic layer.

to Encapsulation of the photovoltaic modules, which are moisture-proof after encapsulation and weather-resistant in the long term, but at the same time must be constructed translucent, is after the present state of the art uses an adhesive adhesive, which is usually in solid form at room temperature. EVA films (ethyl vinyl acetate), TPU films are used (thermoplastic polyurethane), ionomer films or PVB films (Polyvinyl butyral). Alternatively, can also be liquid applied hot melt adhesive, z. As PUR (polyurethane) or silicones be used.

The used adhesives have in common that during the Bonding process either reactivated via temperature must be (thermoplastics) or over temperature, possibly over temperature and pressure, reactivated and cured, d. H. networked, must be. In this process must be avoided be that air bubbles between the different layers the structure of the photovoltaic module remain or reform, which has both lasting weather resistance and moisture resistance of the photovoltaic module produced could adversely affect as well as by refraction reduce the efficiencies of the module could.

The bonding (also called lamination) of the photovoltaic module with the above-mentioned adhesives is done according to the current state of the art mostly in so-called one-level or multi-level vacuum laminators. Due to the relatively long cycle times, usually from several minutes to half an hour, today the larger multi-storey vacuum laminators (or multi-level vacuum laminating presses) usually come into question. Such a multi-level Vakuumlaminierpresse is z. B. in the EP 1 609 597 A2 described. Another alternative embodiment is in the DE 10 2007 034 135 A1 described. Both said methods and devices have in common that the photovoltaic modules to be bonded are heated in several floors one above the other under vacuum and glued together.

Object of the present invention:

In front the backdrop of rising global demand and increasing demand Necessity of a cost-effective and in particular energy-efficient Production of photovoltaic modules due to declining Government subsidies, it is the objective of the present Invention, the prior art in terms of higher Capacities of a single production plant at the same time Reduction of production costs and energy requirements. At the same time, the number of necessary handling steps reduced for the encapsulation of photovoltaic modules which also leads to a further reduction in production costs leads.

Target achievement according to the invention:

Solved This object is achieved by the invention Process according to claims 1 to 16 and by the device according to the invention according to claims 17 to 26.

The present invention uses, in contrast to the prior art, a continuous production process, in which in one first step, a glass carrier plate, preferably already supplied with the active photovoltaic layer lying thereon a Abrollstation for the necessary adhesive film. In a particular embodiment, this first glass plate can also be preheated, z. B. to a temperature between 50 and 90 ° C, preferably between 60 and 80 ° C. In a second step, the heat-activatable adhesive film used is unwound and placed continuously on the lower glass plate transported to the unwinding station. The glass plate with the heat-activatable adhesive film applied is then transported to another station where a second glass plate is placed on the unwound adhesive film layer.

The in the following further described inventive Device or the inventive method can be used in the same way as for the production of photovoltaic modules also be used for the production of laminated glass. It should in the following the description also for laminated glass be valid. In this case, only the photovoltaic active layer thought away, the rest of the process or the rest of the device remains the same.

In In a particular embodiment, it is provided that this second glass plate with an automatic conveyor is removed from a stack and parallel to the conveyor line the first glass plate passes through a preheating zone, then in the allocation station of the preheating with a handling robot on the continuously forwarded first glass plate is placed together with adhesive film.

in the next step, the package thus formed becomes first Glass plate with photovoltaic module, intervening adhesive film and second glass plate continuously in a double belt press with two promoted circulating press belts. The double belt press is designed so that when entering the pressure range the Pressurization takes place along a precisely defined gap, so that all remaining air bubbles already dangled in the package when entering the double belt press become.

In an alternative embodiment it is provided that before entering the double belt press another calender roller pair upstream, which serves as a deficiency to those between the glass plates Still extant remaining air. This calender roll pair may also be heated to a first contact adhesion of the adhesive adhesive film to achieve no further air between the glass plates allow.

In the continuous double belt press, the collapsed package is pressurized and heated to a temperature above or at the reaction temperature of the adhesive system used. The package is thereby subjected to a pressure of more than 1 bar, preferably more than 3 bar, so that further remaining air bubbles are displaced in the material to the outside. The biggest effect for the displacement of air bubbles but has the above-described form of pressure build-up in the press: The rotating press belts are subjected via a pressure pad with pressure and temperature, the pressure pad on the input side has a movable seal, which on the one hand tolerances in the range of 0 up to 5 mm, particularly preferably from 0 to 1.5 mm, can compensate and at the same time by a pressure peak creates a deficiency effect, the air bubbles left in the package against the feed direction from the material brings out. For this purpose, the inlet-side seal of the pressure pad is movably mounted and acted upon by a pressure P ₁ , which is greater than or equal to the pressure P ₂ within the press. This results in an already mentioned pressure peak, which generates the described lack effect.

in the Within the framework of the experiments carried out, the inventor has that the ventilation of the package at the inlet to the press mainly when going through the above mentioned Pressure peaks occur, but only complete is after a distance of about 1-3 cm behind the input side Poetry.

in the Course of the passage of the formed package through the double belt press a pressure and temperature curve is run, in which the necessary Reaction temperature of the adhesive system reached and depending on the setting the adhesive system is held for a certain time. In a particular embodiment is about a rear part of the pressure pad in the double belt press the passing package back to a final temperature above or at the inlet temperature (room temperature) can be cooled. However, such cooling can in one embodiment also be done behind the press, z. B. by slow cooling in a Kühlwender, in which the finished glued photovoltaic modules over a certain period, eg. B. 20-50 min., In the ambient air be held and thereby cool slowly and gently, without creating too much tension in the glass.

In an alternative embodiment, it is provided that, instead of the adhesive adhesive film unwound from a roll, a hot melt adhesive is used which, via a roll coating machine, is applied in liquid form to the first plate with the photovoltaic layer lying thereon is brought. For this purpose, z. B. a PUR hotmelt can be used. The further steps in the method are the same as described above. In an alternative embodiment, the adhesive film can also be placed as a sheet on the lower glass plate.

A great advantage of the method according to the invention is the continuous process in which a jerky start and deceleration of the photovoltaic modules is avoided. Likewise, the handling by continuous unwinding of the adhesive film to be used is simpler and more cost and resource saving than a manual laying of individual sheets. Due to the continuous operation and the lack of effect of the pressure pad in the double belt press, the use of a vacuum, as in the prior art (see. EP 1 609 597 A2 ) superfluous. The process can thereby be accelerated, so that such a double-belt press plant with the properties according to the invention represents a significantly higher capacity with a comparable capital expenditure. In addition, results from the continuous driving a much lower energy consumption and thus further cost savings compared to the prior art: It must be heated in a multi-level Vakuumlaminierpresse no heating elements or heating plates and cooled again, since the heating plates of the double belt press on the same place throughout the process always remain at the same temperature. It must be heated and cooled down again only the top and bottom circumferential band of the double belt press, which, however, has a significantly lower energy content than the heating plates according to the prior art.

When Another advantage results according to experience a significantly lower downtime and downtime of a continuous working plant with uniform speed opposite an intermittently working plant, where basically many Intermittent processes must be coordinated and the error rate is generally higher as in a continuous process. This also results again in lower energy consumption per manufactured square meter module surface and lower investment costs related to the manufactured capacity.

In an alternative embodiment of the invention Method, the upper applied glass plate by a unwound Cover layer film to be replaced. In this case, the finished one exists Photovoltaic module from a lower glass plate, possibly one thereon first adhesive layer (which can also be omitted), the underlying active photovoltaic layer, an overlying second adhesive layer and a final cover sheet, which can also be handled by a roll. This cover sheet has similar water and weather resistance and serves accordingly as a vapor barrier like a second launched Glass plate. Alternatively, the upper cover sheet film may also be referred to as 2-component film (i.e., already coated with adhesive) be.

In A third embodiment can with the inventive Process to produce a completely flexible photovoltaic module, in the place of the lower and upper glass plate flexible materials (impermeable and weather resistant Cover films) are used. In this case, the entire in the press continuously generated package of various transactions unwound and placed in the middle of the active photovoltaic layer.

The Double belt press may vary depending on the viscosity characteristics the adhesive used to be equipped with a device the leakage of the adhesive from the side edges of the package prevented. For this purpose, preferably a side seal in the form a right and left circumferential strip used. This strip is continuously next to the package between the bands of the Double belt press with introduced and has the same height like the photovoltaic module to be pressed (package). It can the bands are designed as steel bands be.

In an alternative embodiment, the circulating belts of the double belt press as steel belts be designed with a temperature-resistant, flexible coating are provided, for. As rubber or silicone. It may be provided that the coating of the steel bands so is structured that the width of the photovoltaic modules to be pressed with a thinner coating and the edge around which the circumferential steel bands are wider than the one to be pressed Package is provided with a thicker coating, such that the difference in the coating thickness is exactly the thickness of the Parcel corresponds, so the revolving steel belts give a chamber exactly the dimensions of the photovoltaic module to be pressed equivalent.

In the following, some embodiments of the method and apparatus of the invention will be explained. It shows the 1 the process steps for a glass / glass module.

The 2 shows the process steps for a glass / foil module in which the upper glass layer has been replaced by a cover film layer, as well as

the 3 the process steps for a purely flexible photovoltaic module without the use of glass plates.

4 represents the individual process steps in the process.

5 explains a detail of the double belt press, in particular the press inlet and the lack of effect of the inlet side seal.

In 6 an exemplary temperature profile during the passage through the double belt press is shown.

7 illustrates various exemplary product structures.

The 1 shows the individual process steps for a module which consists of two glass plates.

The 2 shows the individual process steps for a module which consists of a glass plate and a film layer.

The 3 shows the individual process steps for a flexible photovoltaic module without glass plates.

In 4 runs on the inlet side a first glass plate ( 1 ) into the device formed by the stations (I), (II), (III), (IV) and (V). From a development (II) an adhesive film is unwound, which deposits in the station (III) on the glass plate with the active photovoltaic layer thereon. In station (IV) a second glass plate ( 4 ) launched on the previous structure. The further unwinding station ( 41 ) is used for alternative processing of a cover layer film, if the upper glass plate is to be replaced by one. The double belt press (V) then takes over the compression of the package. The upper inlet roller ( 51 ) and the underlying inlet roller ( 54 ) such that the incoming packet from the upper (52) and lower ( 55 ) and the upper pressure pad ( 53 ) and the lower pressure pad ( 56 ) is supplied. The double belt press can be used in particular as a double belt press with circulating steel belts ( 52 ), which via an isobaric pressure pad ( 53 ) are pressed against each other. The outlet side rollers are denoted by the reference numerals ( 57 ) 58 ).

This detail is in 5 represented where the inlet drum ( 51 ) the steel strip ( 2 ) feeds the pressure pad. The inlet-side seal ( 3 ) movably mounted and seals the pressure chamber with the pressure P ₁ from the actual pressing pressure P ₂ . Compressing pressure P ₂ can either be via air or a liquid medium, such as. As oil or thermal oil can be generated. Through the two pressure chambers P ₁ and P ₂ is the circumferential seal ( 3 Movable, as indicated by the double arrow in 5 shown. The upper and lower seals thereby form a defect, which presses the remaining air in the package against the direction of feed backwards out of the package.

6 represents an exemplary temperature and pressure curve, in which the inlet of the press at time t _{1 is} reached. The pressure rises from 1 bar to 5 bar, wherein at t _1, a corresponding peak in the pressure of> 5 bar is recorded by the lack of effect of the incoming seal. The temperature in the product rises during the period from t ₁ to t ₂ to the desired process temperature, in this case by way of example 140 ° C and remains between t ₂ and t ₃ at this level. In the period from t ₃ to t ₄ , the temperature is reduced by recooling in the press to a starting temperature from the height of 60 ° C in this case. At t _4, the product leaves the press, so that the pressure goes back to the ambient pressure of 1 bar. The entire period from t ₁ to t ₄ can be between 20 seconds and several minutes, more preferably between 1 and 2 minutes.

7 illustrates various exemplary product packages (packages), e.g. For example, with glass plates with a thickness of about 3 mm, a photovoltaic layer and an overlying adhesive film and finally another glass layer of about 3 mm. By way of example, some air bubbles are drawn, which are removed by the method according to the invention. The alternative product assemblies (packages) with a glass plate and a cover film as well as with two cover films are also shown. In the 7 (a-e) were the photovoltaic (PV) layer by the reference numeral 10 , the adhesive layers by the reference numerals 11 , the cover layer by the reference numeral 12 , the 2-K film by the reference numeral 13 and the cover sheet by the reference numeral 14 designated.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - EP 1609597 A2 [0006, 0018]
• - DE 102007034135 A1 [0006]

Claims (26)

Method for joining at least two plate-shaped Workpieces with at least one heat activatable and / or thermosetting adhesive layer with the following steps: - Feeding one first plate-shaped workpiece to a continuous Double belt press. - placing at least one Layer of the adhesive. - placing at least one second plate-shaped workpiece on the adhesive layer. - Activate and / or curing the structure of at least two plate-shaped Materials and at least one adhesive layer without application of Vacuum during the continuous pressing process in the Double belt press. Method according to claim 1 or 2, characterized that as a plate-shaped material glass of a thickness from 0.5 to 20 mm, more preferably a thickness of 2-5 mm, is used. Method according to one of the preceding claims, characterized in that at least one plate-shaped Material is replaced by a foil. Method according to one of the preceding claims, characterized in that on at least one plate-shaped Workpiece one (still unprotected) photovoltaic module is applied. Method according to one of the preceding claims, characterized in that a double belt press with isobaric Pressure pad is used. Method according to one of the preceding claims, characterized in that a double belt press with steel bands is used with or without rubber / silicone coating. Method according to one of the preceding claims, characterized in that a double belt press with a device for preventing leakage of liquid adhesive on the side edges of the plate-shaped workpiece is used. Method according to one of the preceding claims, characterized in that a double belt press with a surface pressure> 1 bar, preferably> 3 bar, is used. Method according to one of the preceding claims, characterized in that a heating temperature> 100 ° C used becomes. Method according to one of the preceding claims, characterized in that all plate-shaped materials be replaced by foil. Method according to one of the preceding claims, characterized in that adhesive at room temperature in the form a film is present. Method according to one of the preceding claims, characterized in that adhesive is applied as a sheet. Method according to one of the preceding claims, characterized in that adhesive in front of the press from the roll is handled. Method according to one of the preceding claims, characterized in that at least one plate-shaped Material, replaced by foil, unwound from the roll before the press becomes. Method according to one of the preceding claims, characterized in that before the main press a shorter Prepress is the one possible bubble-free hang up allows the slides. Method according to one of the preceding claims, characterized in that the adhesive layer in front of the press liquid is applied as a hotmelt. Continuous double belt press with two revolving Press bands and an upper and a lower pressure pad for pressing a package structure, consisting of a lower plate-shaped workpiece, at least one through Heat reactivatable and / or thermosetting adhesive layer and at least one overlying plate-shaped Workpiece, characterized in that the occupation of the Package before the continuous feed double belt press is executed so that any remaining in the package Air bubbles during entry into the press and the pressing process from the produced composite of lower plate-shaped workpiece and upper plate-shaped Workpiece to be removed. Device according to claim 16 or 17, characterized that the double belt press a pressure pad with a circumferential Used seal that at least on the inlet side so flexible is that a thickness tolerance of the product to be pressed by up to max. 3 mm, more preferably of max. 1 mm, by vertical Movement of the upper and / or lower seal to be intercepted can. Device according to one of the claims 17-18, characterized in that instead of at least one plate-shaped workpiece, a film is used. Device according to one of claims 17-19, characterized in that the composite produced without plate-shaped workpieces exclusively is constructed by the use of flexible film materials. Device according to one of claims 17-20, characterized in that as adhesive a hot melt adhesive in liquid form is applied. Device according to one of claims 17-21, characterized in that the double belt press a circumferential Side sealing system in the form of two flexible cleats on the right and left side of the product structure in the same Strength like the product construction has, which with between the be guided both circumferential press belts. Device according to one of claims 17-22, characterized in that for the double belt press as Pressing bands Steel bands with a thickness of 0.8-3 mm, more preferably 1.2-1.6 mm, are used. Device according to one of claims 17-23, characterized in that the double belt press an isobaric pressure pad used, which as a medium for pressure and heat transfer Air used. Device according to one of claims 17-24, characterized in that the double belt press an isobaric pressure pad used as a medium for pressure and heat transfer oil used. Device according to one of claims 17-25, characterized in that in front of the double belt press a Kalanderwalzenpaar is upstream, which the product package already before the enema pre-pressed into the press.