DE10020784A1 - Photovoltaic module and method for its production - Google Patents

Abstract

The invention relates to a pholtovoltaic module comprising several groups (2-5) of serially mounted solar cells (6, 7, 8) respectively provided with a covering electrode, a rear electrode and an absorber layer between the electrodes; also comprising a device (15) for parallel connection of several groups (2 -5). The invention also relates to a method for producing one such module. According to the invention, the device (15) for parallel connection of several groups (2 - 5) is embodied and arranged in such a way that the electrically conducting rear electrodes (13) of the first solar cell (6) of each group (2 -5) and the electrically conducting rear electrodes (13) of the last solar cell (8) of each group (2 - 5) are electrically connected to each other. According to the inventive method, the several groups (2-5) are disposed on a film (37) which forms the front surface of the module (1), whereupon parallel connection of the several groups and application of the rear side of the film forming the module (1) occur, in addition to optional lamination of the film module.

Description

The invention relates to a photovoltaic module according to the preamble of the patent claim 1 and a method for manufacturing a photovoltaic module according to the Oberbe handle of claim 12.

Photovoltaic modules, also called solar modules, are used by individual solar cells Interconnect module generated electrical energy so that with the help of the module or with several such modules be the performance required for the desired application is provided.

From JP-A-2-244 772 a method is known in which a ribbon-shaped solar cell on egg NEN cylindrical body, on which an adhesive is applied, is wound up in such a way that neighboring solar cells overlap. This overlap is such that the back electrode one solar cell contacts the top electrode of the adjacent other solar cell. The Individual solar cells are pressed into the adhesive at an angle to the horizontal. Between the There is also an insulating film on the adhesive and the cylindrical body. To make of a module, the body wound on the cylinder and the insulating film are cut through  and removed from the cylinder so that a rectangular, thin film module with series-connected solar cells is obtained.

From US-A-5 273 608 a method for embedding photovoltaic devices is known.

In US-A-5 232 519 a photovoltaic module is described in which on the top the lead electrodes of each strand-shaped group of solar cells have a lead strip, too Ableitgrid called, for tapping the voltage generated. To avoid that the lead strips the cover electrode and thus also the absorber layer underneath shadowing, the provision of a V-shaped recess in the entire th module covering layer proposed above each discharge belt. Thereby should the incoming sun rays be redirected so that they do not, if possible, on the hit the respective lead tape.

A method for producing band solar cells based on one-sided with CIS (Copper / indium / diselenide) and its homologues coat copper strips and one for them suitable apparatus is known for example from DE-C2-196 34 580. Thin Layer solar cells based on the Ib / IIIa / VIa compound semiconductors and method for Manufacture of such thin-film solar cells are in the German patent applications 199 21 514 and 199 21 515.

A photovoltaic module according to the preamble of claim 1 is known from US-A- 5 457 057 known. In this module, a number of individual plates are electrically associated with one another otherwise connected that a desired voltage for the respective application and the required electricity is provided. The plates are connected in series to one another generated voltage to increase. It is also commonly mentioned in this document that in some Cases groups of series-connected plates can be connected to each other in parallel to meet the required performance requirements at a given voltage. Also in In this case, so-called drain wires are located in or on the top cover layer of each Plate.

The invention has for its object a photovoltaic module of the type mentioned Way of creating which is more economical and, in particular, more flexible for the respective user can be produced based on the application. The invention is also based on the object of a method to specify such a photovoltaic module.  

This object is achieved by a photovoltaic module with the features of Claim 1 and on the procedural side by a method with the features of the patent Proverb 12 solved.

Advantageous further developments are the subject of the respective subclaims.

According to the invention, the device for parallel connection of the several groups of series-connected solar cells is designed and arranged such that on the one hand the electrically conductive back electrodes of the first solar cell of each group and on the other hand the electrically conductive back electrodes of the last solar cell of each group are electrically connected to one another. Since the occurrence of a shadow surface on the cover electrodes or the Absorberschich th of the solar cells is prevented in a particularly simple manner, since the electrical connection of the individual groups is made from the back of the solar cells. The prevention of shadowing, which can quickly lead to a loss of about 10% of the total solar area, increases the economic efficiency of the module per m ^{2 of} solar area. It is also favorable that the modules are freely selectable in shape, performance and size, so that the performance of the photovoltaic module according to the invention can be flexibly adapted to the respective application, ie to the wishes of the consumer. Ultimately, the module according to the invention therefore offers lower costs per unit of the power achieved or per unit of the area of the module and additionally less weight per unit of the power output.

Each group advantageously forms a strand of a plurality of parallel, ribbon-shaped solar cells. This makes it possible to use the module according to the invention as a so-called Manufacture called film module, which further increases the flexibility. Such one Module is light in weight and is relatively sturdy, so from a 15 to 20 year old Service life of these modules and correspondingly low electricity prices per kWh can be assumed.

According to another development of the invention, adjacent solar cells are themselves mutually overlapping arranged so that the back electrode of a solar cell Cover electrode of the adjacent other solar cell contacted, the solar cells preferred as substantially flat and are each inclined to the horizontal. This makes it possible to easily connect the ribbon-shaped solar cells in series, without the need for additional aids or equipment. By the inclined The arrangement of each solar cell remains the same despite the mutual overlapping contact neighboring solar cells are essentially flat, so that the occurrence of kinks or fault is largely excluded.  

According to another development of the invention, the back electrodes are the first in each case Solar cell of each group and the back electrodes of the last solar cell of each group Weil connected to each other by means of a lead tape, preferably each lead tape is arranged perpendicular to the overlapping series-connected solar cells of each group. There This results in procedural advantages, since the discharge belts are parallel to the feed Direction of a front-side film of the module and thus largely low in terms of equipment Effort can be applied. The parallel connection of the individual groups of So lar cells is located on the back of each solar cell string and thus offers the be Technological advantages already mentioned (avoiding shadowing). A derar Term wiring is simple and can be carried out with little equipment.

According to a preferred first embodiment of the invention, each derivation extends tied across the back electrodes of each group, with one lead near the one End of the back electrodes and the other lead band near the opposite, other End of the back electrodes is arranged and preferably between each one Lead tape and the back electrodes of each group except the back electrode of each first solar cell as well as between the other lead tape and the back electrodes of each Group except the back electrode of the last solar cell an electrical insulation layer is located. With such an arrangement of the discharge belts there is a loss of area completely prevented. The discharge tapes are located within the area of the several Groups of solar cells. The electrical insulating layer ensures that one Dissipation tape exclusively with the back electrode of the first solar cell and the other The discharge band is only in contact with the back electrode of the last solar cell.

According to an advantageous development, there is between the lead-off tapes and the return electrodes that of the solar cells except in the contact area of the discharge belts with the first ones or last solar cells provided a hot melt layer. This serves on the one hand to fill the space between the respective lead tape and the solar cells; she serves but also to fix the respective lead tape so that it is securely in place is held. This creates an extremely compact module in which the appearance of hollow clear and consequent damage to the module are effectively prevented.

According to a preferred second embodiment of the invention, the respective first So Lar cells over one end of their group and the last solar cells over the opposite overlying, other end of their group, with each lead band across the solar cell len each group with mutual connection in the overlap area with the one End protruding or with the rear electrodes protruding at the other end and  outside of that formed by the solar cells except the first solar cells, ei In the end or outside of that by the solar cells except the last solar cell len formed, the other end of each group is arranged. The lead bands are now located that according to this second embodiment of the invention outside the main part of the surface every group. This arrangement saves the application of an insulating layer on the solar cells, as required in the case of the first embodiment of the invention. On the other hand thus a slight increase in module area while remaining essentially constant Performance connected. This embodiment therefore offers advantages in particular if a sufficiently large area is available for installing the photovoltaic modules.

The multiple groups are advantageously all-round in a heat-activatable plastic embedded. As a result, the module is largely protected against negative environmental influences. He is still flexible, and can therefore also be used on curved or curved surfaces.

The inventive method according to the features of claim 12 offers the Advantage that the individual groups in a simple manner on the back of a front page lie of the module can be applied. Through the subsequent parallel connection The several groups ensure that the interconnection of the solar cells to one or several modules are shifted to the module assembly and therefore unlike others Thin film process a simpler technology with less process engineering single steps can be used. The module size can be independent of the size of the Solar cells can be designed freely. A so-called scaling of the technical systems and Special equipment for the production of solar cells can thus be omitted. Because of the low Given the number of technological steps involved, the manufacturing process can be relatively simple be carried out, which ultimately leads to a significant reduction in solar power gesture costs. In addition, according to the invention, the application of so-called Ab Leitgrids are dispensed with.

The front-side film is advantageously pulled off a roll and becomes belt-like sized solar cells with overhead electrodes at right angles to the direction of advance of the front ten film applied to this, preferably the front film before application the solar cells are heated and the solar cells under mutual overlap, the Back electrode of one solar cell the top electrode of the other, neighboring solar cell contacted, inclined to the horizontal, pressed into the front film. So that can the method according to the invention is carried out in a so-called roll-to-roll process become. But it is also possible to have only one role, i. H. the roll for the front side film, to be provided and the film at the end of the process into individual modules of the desired specification  to cut up. The ribbon-shaped solar cells can also be pulled off a roll be. Due to the mutual contacting of neighboring solar cells, these can in a simple manner by superimposing the movement of the front-side film with the one gene when applying the solar cell to the film. Because of the feed speed of the front film, the solar cells are each only a short distance in Carrying direction of the film. This offers advantages in terms of apparatus design of the method according to the invention.

According to another development of the invention, the back electrodes of each group on the one hand near one end except on the back electrode of the first solar cell and on the other hand near the opposite, other end except for the Back electrode of the last solar cell a strip-shaped electrical insulation layer applied, preferably on the back electrodes of each group primarily in the area the insulating layer except in the contact areas over which the back electrodes of the first solar cell of each group or the back electrodes of the last solar cell of each group because they are to be electrically connected to each other, a hot melt layer is applied, preferably sprayed on. With the help of applying the strip-shaped electrical Insulating layer is a simple way to create the lead tape still to be applied to isolate from the other back electrodes of the respective group. With that the electrical voltage is tapped only at those points which are appropriate for a purpose Parallel connection of the individual groups is advantageous. Since the insulating layers and the Hot melt layers run essentially parallel to one another, can on the one hand Insulating layers and on the other hand the hot melt layers on the substantially simultaneously Solar cells are applied. This leads to a device-compact device for Carrying out the method and accelerating the carrying out of the method according to the invention rens for making a module. The hot melt layer mentioned serves in the sense of a Double action on the one hand to avoid cavities in the module and on the other hand too fixing the respective lead tape.

Advantageously, the back electrode is applied to the hot melt layers and the contact areas electrodes of the first solar cell of each group or the contact areas of the back electrodes of the a lead tape applied to the last solar cell of each group. So that the discharge belt can cross run over the solar cells, which simplifies the application of the discharge tape. Nevertheless contacts the lead tape only certain back electrodes, insofar as this is for the desired Parallel connection is technically necessary and useful.  

According to another embodiment of the method according to the invention, the first Solar cells of each group or the last solar cells of each group on the front applied film that the first solar cells over one end of their group and the project the last solar cells over the opposite, other end of their group, the protruding sections of the first and last solar cells with one lead band each can be connected to each other. As previously in the explanation of the inventions specified module, in this case is the application of an insulating layer on the Back electrodes of each group can be dispensed with.

The insulating layer, the hot-melt layer, is advantageously applied, if provided these are present, and the discharge belts transverse to the longitudinal direction of the solar cells or parallel to the feed direction of the front sheet, which is the implementation of the fiction can further simplify the procedure since there is the possibility of moving to a Delivery mechanism for the device for applying the insulating layer or the hot to completely dispense with the melt layer.

According to a preferred development, the method according to the invention is continuous ongoing process, whereby the manufacture of photovoltaic modules is not insignificant can be accelerated.

Exemplary embodiments of the subject matter of the invention are described below with reference to the drawings gene explained in more detail. Show it:

Figure 1 is a schematic bottom view of a first embodiment of a Photovoltaikmo module during its manufacture.

FIG. 2 shows a schematic bottom view of the photovoltaic module according to FIG. 1 with two series-connected solar cells;

. Fig. 3 is a schematic bottom view of the module of Figure 1 with a group serienver switched solar cells;

FIG. 4 shows a schematic bottom view of the module according to FIG. 3 with four groups of series-connected solar cells;

FIG. 5 shows a schematic bottom view of the module according to FIG. 4 with insulating layers partially applied to the solar cells;

FIG. 6 shows a schematic bottom view of the module according to FIG. 5 with conductor tapes applied to the insulating layers and rear electrodes;

Fig. 7 is a schematic, partial longitudinal sectional view of a photovoltaic module near its one end according to a first embodiment of the invention;

FIG. 8 shows a schematic, partial longitudinal section through the photovoltaic module near its opposite, other end according to the first embodiment of the invention; FIG.

Fig. 9 is a schematic bottom view of a photovoltaic module according to a second embodiment of the invention during its manufacture;

FIG. 10 shows a schematic bottom view of the module according to FIG. 9 with lead strips applied to a part of the back electrodes; FIG.

Fig. 11 is a schematic bottom view of the photovoltaic module according to the first approximate shape exporting;

Fig. 12 is a schematic bottom view of the photovoltaic module according to Figure 11 with module junction box.

FIG. 13 is a schematic bottom view of the photovoltaic module according to FIG. 12 with module frame; and

FIG. 14 shows a schematic top view of the photovoltaic module according to FIG. 13.

A schematic longitudinal section near an upper end of a photovoltaic module 1 according to a first embodiment of the invention is shown in FIG. 7 and a schematic longitudinal section near a lower end of the photovoltaic module 1 according to the first embodiment of the invention is shown in FIG. 8.

Each photovoltaic module 1 has several groups 2 , 3 , 4 , 5 series- connected solar cells 6 , 7 , 8 , with only two groups of three series-connected solar cells being shown in FIGS . 7 and 8 for the sake of simplicity.

It should be noted that 11 of each photovoltaic module 1 is arranged at the top in FIGS. 7 and 8, the front face 10 of each photovoltaic module 1 below and the rear.

Each solar cell 6 , 7 , 8 has a cover electrode 12 , a back electrode 13 and between the electrodes 12 , 13 an absorber layer 14 , these three elements in FIG. 7 with reference characters for the sake of clarity only with regard to the solar cell belonging to group 2 8 are shown. The structure of the other solar cells 6 and 7 in FIGS. 7 and 8 corresponds to that of the solar cell 8 according to FIG. 7.

The structure of the solar cells 6 , 7 , 8 is only shown schematically in FIGS. 7 and 8. The solar cells can be constructed in such a way as is exemplified in documents DE-C2-196 34 580, DE 199 21 514 and DE 199 21 515, the content of which is referred to here.

According to this, the solar cells are so-called thin-film solar cells with a total thickness of approximately 30 μm to approximately 100 μm and a width of approximately 1 cm. The absorber layer 14 is preferably a so-called CIS absorber layer made of copper indium diselenide (CuInSe ₂ ) or copper indium disulfide (CuInS ₂ ). Other absorber layers, for example made of copper gallium diselenide (CuGaSe ₂ ), copper gallium disulfide (CuGaS ₂ ) and mixtures of these elements (Cu (In, Ga) (Se, S) ₂ ), can also be used. These compound semiconductors from groups Ib / IIIa / VIa of the periodic table have a band gap suitable for solar applications and can therefore theoretically convert up to 30% of sunlight into electrical energy. They have a high absorption coefficient, so that a very thin semiconductor layer of about 1 µm is sufficient to absorb at least 90% of the sunlight. Each solar cell is able to separate the light-generated charge carrier pairs, so that the charge carriers on the transparent, highly conductive cover electrode, also called the cover layer, or, as described according to the invention, can be dissipated on the back electrode. Methods for producing such ribbon-shaped solar cells are detailed in the last three documents mentioned.

According to the invention, the photovoltaic module 1 has a device 15 for connecting the plurality of groups 2 to 5 in parallel, which is designed and arranged such that on the one hand the electrically conductive back electrodes 13 of the first solar cell 6 of each group 2 to 5 (see FIG. 7) and on the other hand the electrically conductive back electrodes 13 of the last solar cell 8 of each group 2 to 5 (see FIG. 8) are electrically connected to one another.

Each group 2 to 5 forms a strand 20 to 23 of a plurality of ribbon-shaped solar cells 6 , 7 and 8 arranged parallel to one another. It is pointed out that, as shown in FIGS . 7 and 8, only three series-connected solar cells are shown. Referring to FIGS. 3 to 6, a strand by way of example also of ten series-connected solar cells shown in FIGS. 9 and 10 also of series of nine solar cells exist, the number of serienver switched solar cells of the desired, to be obtained voltage, that is, from a practical application, forth, is largely predetermined and can vary within wide limits.

Referring to FIGS. 7 and 8 are mutually adjacent solar cells 6, 7 and 7, 8 arranged opposite each other to overlap in such a way that the back electrode of the other solar cell contacts 13 of the one solar cell 6 and 7, the top electrode 12 7 and 8 respectively. From FIGS. 7 and 8 it can be seen further that the solar cells 6, 7, 8 is substantially planar and each talen to Horizon are inclined.

According to the invention, the back electrodes 13 of the first solar cell 6 of each group 2 to 5 and the back electrodes 13 of the last solar cell 8 of each group 2 to 5 are each electrically connected to one another by means of a lead tape 24 , 25 , wherein, as will be described in more detail later, each discharge belt 24 , 25 is arranged perpendicular to the overlapping series-connected solar cells 6 , 7 , 8 of each group 2 to 5 .

According to the photovoltaic module of the first embodiment of the invention, which is shown in FIGS. 1 to 6, 7, 8 and 11 to 14, each lead band 24 , 25 extends across the back electrodes 13 of groups 2 to 5 , the one lead band 24 near one end 26 (in FIG. 6, this is the upper end) of the back electrodes 13 and the other discharge band 25 near the opposite, other end 27 (in FIG. 6, this is the lower end) of the back electrodes 13 is arranged. It is clear that the lead bands 24 , 25 are not necessarily to be placed near the two ends of the module. They can be arranged anywhere else on the back of the module, for example directly next to one another. As indicated previously, FIG. 7 shows a longitudinal section through the module and thus a cross section through each solar cell near one upper end 26 and FIG. 8 near the opposite other lower end 27 of each module.

From FIGS. 7 and 8 that in each case between the one discharge strap 24 and the back electrode 13 of each group except for the back electrode 13 of each of the first solar cell 6, and between the other discharge strap 25 and the back electrodes 13 per group except for the back electrode can also be seen, 13 of the last solar cell 8 there is an electrical insulating layer 30 . Referring to FIGS. 7 and 8 surrounds this insulating layer 30 which in question solar cells, in the case of Fig. 7, the solar cells 7 and 8 and in the case of 8, the solar cell 6 and 7 roughly L-shaped as shown in the right half of FIG. ie the insulating layer covers part of the underside, namely the back electrode 13 , each solar cell and the respective left end of the solar cells in the figures, which is formed by the free sections of the top electrode 12 , absorber layer 14 and back electrode 13 . The insulating layers preferably consist of inorganic dielectric materials such as titanium oxide or silicon oxide; however, organic electrical insulating lacquers can also be used.

As further shown in FIGS . 7 and 8, is between the discharge bands 24 , 25 and the back electrodes of the solar cells 6 , 7 , 8 except in the contact area 31 in the case of the illustration of FIG. 7 and except in the contact area 32 in the case of the illustration with the respective first or last solar cell 6, 8 is provided a hot melt layer 33 of FIG. 8 of the Ableitbänder. The hot melt layer can preferably take over the function of the insulating layer at the same time in the sense of a double function. According to FIGS. 7 and 8, the hot-melt layer 33 fills the entire space between the respective discharge band 24 or 25 and the solar cells. The hot melt layer 33 is preferably a heat-activatable plastic. Advantageously, the heat-activatable plastic is ethylene vinyl acetate (EVA) and thus the same plastic that is also used for embedding the module. It is also possible to obtain other plastics, in particular so-called hot melt adhesives such as macromelt 6208, from Henkel KGa. A. Düsseldorf, can be used.

A second embodiment of the photovoltaic module 1 is shown schematically in a bottom view in FIGS . 9 and 10.

In this embodiment, the first solar cells 6 protrude from one end 26 of their group 2 to 5 and the last solar cells 8 from the opposite, other end 27 of their group 2 to 5 . Each discharge band 24 , 25 extends transversely to the solar cells 6 , 7 , 8 of each group 2 to 5 with mutual connection in the overhang area 24 , 25 ( FIG. 10) with those protruding at one end 26 or protruding at the other end 27 Back electrodes 13 of each group and outside the one end 26 formed by the solar cells 6 to 8 except for the first solar cells 6 or outside the other end 27 formed by the solar cells 6 to 8 except the last solar cells 8 , as shown schematically is indicated in Fig. 10.

Groups 2 to 5 are embedded on all sides in a heat-activatable plastic 36 , as is indicated by way of example in FIGS . 7, 8, 13 and 14. In the case of the cover layer of the module on the front 10 , this activatable plastic 36 is transparent and consists, for example, of EVA. Such a plastic liquefies from 80 to 100 ° C and preferably forms at about 150 ° C crosslinking. Such a transparent heat-activatable plastic is, for example, the product ETIMEX ELVAX from BP Chemicals PlasTec. Other heat-activatable plastics can also be used. It is clear that such a plastic becomes sticky when it is melted or crosslinked. The lower layer forming the rear side 11 of each module can also consist of such a heat-activatable plastic 36 . But it is also possible to form the latter layer, for example, by a non-transparent plastic. To prevent weathering, a cover film can be applied to the heat-activated plastic, which is transparent on the front of the modules. Such a transparent film is, for example, the Tefzel product from Dupont. On the back can also non-transparent films or composite films such. B. the products ICOSOLAR from ISOVOLTA can be used.

In addition, the exact structure of the photovoltaic module 1 according to the invention results from the following description of a method according to the invention for producing such a module. This process is explained in more detail below.

Referring to FIG. 1, a band-shaped solar cell 6 is placed overhead back electrode 13 on a front face sheet 37 transverse its longitudinal direction. The front-side film is shown in FIG. 1 merely as an example as a rectangular area. Preferably, the front side film 37 is pulled off a roll, not shown, on which the film is wound. The band-shaped solar cell 6 is then applied transversely to the feed direction, which is indicated by the arrow A in FIG. 1 by way of example.

For this purpose, the front-side film 37 is heated before the individual solar cells are applied. The solar cells are inclined then mutual overlap (see FIGS. 2 to 4) to the horizontal (see also Fig. 7 and 8) is pressed into the front face sheet 37, in which, as shown in FIGS. 7 and 8, the back electrode 13 of a Solar cell 6 or 7 contacts the top electrode 12 of the other, adjacent solar cell 7 or 8 . Accordingly, the next solar cell 7 is placed overlapping on the solar cell 6 shown in FIG. 1 so that the area visible in FIG. 1 is partially covered. For the sake of a better overview, this reduction in cross section in the illustration according to FIG. 2 in comparison with that of FIG. 1 is very clearly formed. It is clear that, as shown in FIGS. 7 and 8, adjacent solar cells overlap only slightly. To the solar cell 7 shown in FIG. 2 now follow further solar cells until finally the last solar cell 8 of this first group, which receives the reference symbol 2 , is applied. Accordingly, group 2 includes a first solar cell 6 , eight solar cells 7 and a last solar cell 8 . Accordingly, the solar cells 6 to 8 of this group 2 are connected in series with one another.

As already mentioned in the brief description of the drawings, FIGS . 1 to 6 and 9 to 13 show a schematic bottom view of a photovoltaic module 1, which is partly being manufactured.

Subsequently, 40 further groups 3 , 4 , 5 are applied in an analogous manner to the front-side film 37 , leaving an intermediate distance in each case. According to FIG. 4, the Photo voltaikmodul 1 thus four different groups 2 to 5, that is, four strands 20 to 23 respectively se rienverschalteter solar modules. As mentioned above, any number of groups of series-connected solar cells can be placed on the front film pulled from a roll, the individual modules usually being formed at the end of the production process by cutting a band-shaped module. If a rectangular front-side film 37 is shown in the figures, this can also be a so-called endless front-side film.

Then, on the back electrodes 13 of each group 2 to 5, on the one hand near one end 26 except on the back electrode 13 of the first solar cell 6 and on the other hand near the opposite, other end 27 except on the back electrode 13 of the last solar cell 8, the strip-shaped, electrical insulating layer 30 according to FIG. 5 applied. Near the upper end 26 of the solar module 1 on each group 2 to 5, an insulating layer 30 and near the other end 27 only on the groups 3 to 5, the insulating layer 30 .

Then the back electrodes 13 of each group 2 to 5 are primarily in the area of the insulating layer 30 except in the contact areas 31 , 32 , via which the back electrodes 13 of the first solar cell 6 of each group 2 to 5 or the back electrodes 13 of the last solar cell 8 of each group 2 to 5 are to be connected to one another, the hot melt layer 33 is applied, in particular sprayed on. This hot melt layer 33 is shown in FIGS. 7 and 8 ge and omitted in Fig. 6 for better clarity and illustration.

In a next process step, a lead tape 24 , 25 is applied to the hot melt layers 33 and the contact areas 31 of the back electrodes 13 of the first solar cell 6 of each group 2 to 5 or the contact areas 32 of the back electrodes 13 of the last solar cell 8 of each group 2 to 5 . The device 15 according to the invention for connecting several groups 2 to 5 in parallel therefore has, in accordance with the first embodiment of the invention shown in FIGS. 1 to 8 and 11 to 14, a discharge band 24 , 25 which is either in the contact areas 31 , 32 is connected directly to the solar cells or rests indirectly on the solar cells via the hot melt layer 33 and the insulating layer 30 .

A second embodiment of a photovoltaic module 1 is shown schematically in FIGS. 9 and 10 in a bottom view.

For this purpose, the first solar cells 6 of each group 2 to 5 or the last solar cells 8 of each group 2 to 5 are applied to the front side film 37 in such a way that the first solar cells 6 in each case via one end 26 of their group 2 to 5 and the last one Solar cells 8 protrude from the opposite, other end 27 of their group 2 to 5, the projecting sections 41 , 42 of the first and the respectively last solar cells 6 , 8 according to FIG. 10 being connected to each other with a lead tape 24 , 25 . Referring to FIG. 10, the discharge strap 24 is from one end 26 of the solar cells 7 and 8 and the opposite discharge strap 25 from the opposite, other end 27 of the solar cell 6 and 7 spaced apart. In the case of the discharge belt 24 , this distance in FIG. 10 is very small at one end 26 and in the case of the discharge belt 25 at the other end 27 it is significantly larger. It is clear that the distance between the discharge belts and the solar cells that are not in contact can also be formed uniformly and is usually only a small dimension, for example 0.5 to 1 mm.

The insulation layer 30 and the hot melt layer 33 , if present, as in the case of the first embodiment of the invention, and the discharge strips 24 , 25 are applied transversely to the longitudinal direction of the solar cells 6 , 7 , 8 or, if the front-side film 37 is not covered by one shown roll is pulled off, along the feed direction (see arrow A in Fig. 1) of the front side film 37th

The method according to the invention can also be a continuous process, wherein the strip-shaped solar cells 6 , 7 , 8 can also be pulled off a roll and foil 37 applied to the front sides.

A further film 43 , the so-called backside film, which is shown in FIGS. 7 and 8, is then applied to the rear side of the modules formed in accordance with FIGS. 6 and 10. The module is then, if necessary, subjected to a lamination process and either wound up on a roll or, if necessary, cut into the desired modules.

It is clear that each module has electrical connections 44 (cf. FIG. 11), which according to FIG. 12 are covered by a so-called module junction box 45 . Typically, the photovoltaic module 1 thus prepared is subjected to a framing 46 which is schematically shown in relation to the rear side 11 of the module 1 in Fig. 13 (bottom view) and in relation to the front face 10 of the module shown in FIG. 14 (top view). Fig. 14 shows that the discharge tapes 24 , 25 rest on the solar cells from the rear of the module. Short sections of the discharge belts 24 , 25 are visible in FIG. 14 in the intermediate distances 40 of the individual groups or strands.

The method according to the invention is accordingly carried out by the following steps:

• Applying a plurality of groups 2 to 5 of series- connected solar cells 6 , 7 , 8 to a film 37 forming the front 10 of the module 1 ,
• Parallel connection of the plurality of groups 2 to 5 by mutually connecting one side of the back electrodes 13 of the first solar cell 6 of each group 2 to 5 and on the other hand the back electrodes 13 of the last solar cell 8 of each group 2 to 5 ,
• - Application of a film 43 forming the rear side 11 of the module 1 and, if required, laminating the film module.

The application of the solar modules to the front side film 37 or the application of the back side film 43 to the module is preferably carried out by a so-called lamination of the ribbon-shaped solar cells or the back side film.

According to the invention, the provision of special electrical leads, also lead grids called, completely eliminated.

This makes it possible to simplify a powerful photovoltaic module by means of a manufacture feasible process.

Claims (20)

1. Photovoltaic module
With several groups ( 2 , 3 , 4 , 5 ) of series-connected solar cells ( 6 , 7 , 8 ), which solar cells ( 6 , 7 , 8 ) each have a cover electrode ( 12 ), a back electrode ( 13 ) and between the electrodes ( 12 , 13 ) have an absorber layer ( 14 ), and
with a device ( 15 ) for connecting the plurality of groups ( 2 to 5 ) in parallel,
characterized by
that the device ( 15 ) for connecting the plurality of groups ( 2 to 5 ) in parallel is designed and arranged such that on the one hand the electrically conductive back electrodes ( 13 ) of the first solar cell ( 6 ) of each group ( 2 to 5 ) and on the other hand the electrically conductive back electrodes ( 13 ) of the last solar cell ( 8 ) of each group ( 2 to 5 ) are electrically connected to one another. 2. Photovoltaic module according to claim 1, characterized in that each group ( 2 to 5 ) forms a strand ( 20 , 21 , 22 , 23 ) of a plurality of ribbon-shaped solar cells ( 6 , 7 , 8 ) arranged parallel to one another. 3. Photovoltaic module according to claim 2, characterized in that adjacent solar cells ( 6 , 7 , 8 ) are mutually overlapping such that the Rückelek electrode ( 13 ) of one solar cell ( 6 , 7 ) the top electrode ( 12 ) of the other Contacted solar cell ( 7 , 8 ). 4. Photovoltaic module according to one of the preceding claims, characterized in that the solar cells ( 6 , 7 , 8 ) are formed substantially flat and are each arranged inclined to the horizontal. 5. Photovoltaic module according to one of the preceding claims, characterized in that the back electrodes ( 13 ) of the first solar cell ( 6 ) of each group ( 2 to 5 ) and the back electrodes ( 13 ) of the last solar cell ( 8 ) of each group ( 2 to 5 ) are connected to each other by means of a discharge belt ( 24 , 25 ). 6. Photovoltaic module at least according to claims 3 and 5, characterized in that each discharge belt ( 24 , 25 ) is arranged perpendicular to the overlapping series-connected solar cells ( 6 , 7 , 8 ) of each group ( 2 to 5 ). 7. Photovoltaic module according to claim 5 or 6, characterized in that each lead band ( 24 , 25 ) extends across the back electrodes ( 13 ) of each group ( 2 to 5 ), the one lead band ( 24 ) near one end ( 26 ) of the back electrodes ( 13 ) and the other re discharge band ( 25 ) near the opposite, other end ( 27 ) of the back electrodes ( 13 ) is arranged. 8. Photovoltaic module according to claim 7, characterized in that between the one lead band ( 24 ) and the back electrodes ( 13 ) of each group ( 2 to 5 ) except the back electrode ( 13 ) of the first solar cell ( 6 ) and between the another discharge band ( 25 ) and the back electrodes ( 13 ) of each group ( 2 to 5 ) with the exception of the back electrode ( 13 ) of the last solar cell ( 8 ) there is an electrical insulating layer ( 30 ). 9. Photovoltaic module according to claim 7 or 8, characterized in that between the lead bands ( 24 , 25 ) and the back electrodes ( 13 ) of the solar cells ( 6 , 7 , 8 ) except in the contact area ( 31 , 32 ) of the lead bands ( 24 , 25 ) with the first and last solar cells ( 6 and 8 ) a hot melt layer ( 33 ) is provided. 10. Photovoltaic module according to claim 5 or 6, characterized in that the most he solar cells ( 6 ) on one end ( 26 ) of their group ( 2 to 5 ) and the last solar cells ( 8 ) on the opposite, other end ( 27 ) of their group ( 2 to 5 ) and that each discharge band ( 24 , 25 ) transversely to the solar cells ( 6 , 7 , 8 ) of each group ( 2 to 5 ) with mutual connection in the overhang area ( 34 , 35 ) with the protruding at one end ( 26 ) or with the other end ( 27 ) protruding rear electrodes ( 13 ) and outside the one formed by the solar cells except the first solar cells ( 6 ), one end ( 26 ) or outside the other end ( 27 ) of each group ( 2 to 5 ), which is formed by the solar cells len ( 6 , 7 ) except the last solar cells ( 8 ) formed. 11. Photovoltaic module according to one of the preceding claims, characterized in that the plurality of groups ( 2 to 5 ) are embedded on all sides in a heat-activatable plastic ( 36 ). 12. A method for producing a photovoltaic module according to one of the preceding claims, characterized by the following steps:

• - Applying several groups ( 2 to 5 ) of series-connected solar cells ( 6 , 7 , 8 ) to a film ( 37 ) forming the front side ( 10 ) of the module ( 1 );
• - Connecting the plurality of groups ( 2 to 5 ) in parallel by mutually connecting one side of the back electrodes ( 13 ) of the first solar cell ( 6 ) of each group ( 2 to 5 ) and another of the back electrodes ( 13 ) of the last solar cell ( 8 ) of each group ( 2 to 5 );
• - Application of a film ( 43 ) forming the rear side ( 11 ) of the module ( 1 ).

13. The method according to claim 12, characterized in that the front side film ( 37 ) is pulled off a roll and ribbon-shaped solar cells ( 6 , 7 , 8 ) with overhead rear electrodes ( 13 ) transversely to the direction of advance of the front side film ( 37 ) are brought onto this . 14. The method according to claim 13, characterized in that the front film ( 37 ) is heated before the application of the solar cells ( 6 , 7 , 8 ) and the solar cells with mutual overlap ge, the back electrode ( 13 ) of a solar cell ( 6 , 7 ) the Dec kelektrode ( 12 ) of the other, adjacent solar cell ( 7 , 8 ) contacted, inclined to the horizontal in the front side film ( 37 ) are pressed. 15. The method according to any one of claims 12 to 14, characterized in that on the back electrodes ( 13 ) of each group ( 2 to 5 ) on the one hand near the one end ( 26 ) except on the back electrode ( 13 ) of the first solar cell ( 6th ) and on the other hand near the opposite, other end ( 27 ) except on the back electrode ( 13 ) of the last solar cell ( 8 ) a strip-shaped, electrical insulating layer ( 30 ) is brought up. 16. The method according to claim 15, characterized in that on the back electrodes ( 13 ) of each group ( 2 to 5 ) mainly in the region of the insulating layer ( 30 ) except in the contact areas ( 31 , 32 ) through which the back electrodes ( 13 ) a hot melt layer ( 33 ) is applied to the first solar cell ( 6 ) of each group ( 2 to 5 ) or the back electrodes ( 13 ) of the last solar cell ( 8 ) of each group ( 2 to 5 ). 17. The method according to claim 16, characterized in that on the hot melt layers ( 33 ) and the contact areas ( 31 ) of the back electrodes ( 13 ) of the first solar cell ( 6 ) of each group ( 2 to 5 ) or the contact areas ( 32 ) Back electrodes ( 13 ) of the last solar cell ( 8 ) of each group ( 2 to 5 ) a lead tape ( 24 , 25 ) is applied. 18. The method according to any one of claims 12 to 14, characterized in that the respective first solar cells ( 6 ) of each group ( 2 to 5 ) or the last solar cells ( 8 ) of each group ( 2 to 5 ) on the front film ( 37 ) are applied that the respective first solar cells ( 6 ) over one end ( 26 ) of their group ( 2 to 5 ) and the last solar cells ( 8 ) over the opposite, other end ( 27 ) of their group ( 2 to 5 ) protrude and that the protruding sections ( 41 , 42 ) of each of the first and the last solar cells ( 6 and 8 ) are connected to each other with a discharge band ( 24 , 25 ). 19. The method according to any one of claims 12 to 18, characterized in that the bringing on the insulating layer ( 30 ) and the hot melt layer ( 33 ), if these are present, and the discharge belts ( 24 , 25 ) transversely to the longitudinal direction of the solar cells ( 6 , 7 , 8 ) or parallel to the feed direction (arrow A) of the front side film ( 37 ). 20. The method according to any one of claims 12 to 19, characterized by a continuous ongoing process.