WO2001084638A2

WO2001084638A2 - Photovoltaic module and method for the production thereof

Info

Publication number: WO2001084638A2
Application number: PCT/EP2001/004349
Authority: WO
Inventors: Olaf Tober; Ralf GÜLDNER; Jürgen PENNDORF; Gudrun Barth
Original assignee: Ist - Institut Für Solartechnologien Gmbh; Odersun Photovoltaics Gmbh
Priority date: 2000-04-28
Filing date: 2001-04-17
Publication date: 2001-11-08
Also published as: EP1307925A2; DE10020784A1; AU2001273948A1; WO2001084638A3

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

Photovoltaic module and method for its production

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

Photovoltaic modules, also called solar modules, serve to interconnect the electrical energy generated by individual solar cells of the module in such a way that the power required for the desired application is provided with the aid of the module or with several such modules.

From JP-A-2-244 772 a method is known in which a ribbon-shaped solar cell is wound onto a cylindrical body to which an adhesive is applied in such a way that adjacent solar cells overlap. This overlap is such that the back electrode of 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 and the cylindrical body. To manufacture a module, the body wound on the cylinder and the insulating film are passed through cut 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.

US Pat. No. 5,232,519 describes a photovoltaic module in which a lead strip, also called a lead grid, is located on the top of the top electrodes of each strand-shaped group of solar cells for tapping the voltage generated. In order to prevent the lead strips from shading the cover electrode and thus also the absorber layer underneath, the provision of a V-shaped recess in the cover layer covering the entire module above each lead band is proposed in this document. As a result, the incident sun rays are to be deflected in such a way that they preferably do not strike the respective deflection band.

A method for producing band solar cells based on one-sided with CIS

(Copper / indium / diselenide) and its homologues coat copper strips and a suitable apparatus for this is known, for example, from DE-C2-196 34 580. Thin-film solar cells based on the Ib / ffla / VIa compound semiconductors and methods for producing such thin-film solar cells are described in German patent applications 19921 514 and 19921 515.

A photovoltaic module according to the preamble of claim 1 is known from US-A-5457057. In this module, a number of individual plates are electrically connected to one another in such a way that a voltage and the current required for the respective application is provided. The plates are connected in series to increase the voltage generated. It is also generally mentioned in this document that in some cases groups of series-connected plates can be connected in parallel in order to meet the required performance requirements at a given voltage. In this case too, so-called drain wires are located in or on the top cover layer of each plate.

The object of the invention is to create a photovoltaic module of the type mentioned at the outset which can be produced more economically and in particular more flexibly in relation to the respective application. The invention is also based on the object of specifying a method for producing such a photovoltaic module. This object is achieved according to the invention by a photovoltaic module with the features of patent claim 1 and on the process side by a method with the features of patent claim 12.

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. As a result, the occurrence of a shadow surface on the cover electrodes or the absorber layers of the solar cells is prevented in a particularly simple manner, since the electrical connection of the individual groups takes place from the rear 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 can be freely selected in terms of 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 string of a plurality of ribbon-shaped solar cells arranged parallel to one another. This makes it possible to produce the module according to the invention as a so-called film module, which further increases the flexibility. Such a module has a low weight and is relatively robust, so that 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 mutually overlapping in such a way that the back electrode of one solar cell contacts the top electrode of the adjacent other solar cell, the solar cells preferably being essentially flat and each being inclined to the horizontal. As a result, a series connection of the band-shaped solar cells is possible in a simple manner, without the need for additional aids or equipment. Due to the inclined arrangement of each solar cell, it remains essentially flat despite the mutual overlapping contacting of adjacent solar cells, so that the occurrence of buckling or warping is largely excluded. According to another development of the invention, the back electrodes of the first solar cell in each group and the back electrodes of the last solar cell in each group are connected to one another by means of a lead tape, each lead band preferably being arranged perpendicular to the overlapping series-connected solar cells of each group. This results in advantages in terms of process technology, since the discharge belts can be applied parallel to the direction of advance of a front-side film of the module and thus with little outlay in terms of apparatus. The parallel connection of the individual groups of solar cells is thus on the back of each solar cell string and thus offers the technological advantages already mentioned (avoiding shadowing). Such an interconnection has a simple structure and can be carried out with little expenditure on equipment.

According to a preferred first embodiment of the invention, each lead strip extends across the back electrodes of each group, the one lead band being arranged near one end of the back electrodes and the other lead band near the opposite, other end of the back electrodes and preferably in each case between the one

Lead strip and the back electrodes of each group except the back electrode of the first solar cell and between the other lead band and the back electrodes of each group except the back electrode of the last solar cell is an electrical insulating layer. With such an arrangement of the discharge belts, a loss of area is completely prevented. The discharge tapes are located within the area of the several

Groups of solar cells. The electrical insulating layer ensures that one lead band is only in contact with the back electrode of the first solar cell and the other lead band is in contact only with the back electrode of the last solar cell.

According to an advantageous development, a hot-melt layer is provided between the lead-off tapes and the back electrodes of the solar cells, except in the contact area of the lead-off tapes with the first and last solar cells. On the one hand, this serves to fill the space between the respective discharge band and the solar cells; but it also serves to fix the respective discharge tape so that it is held securely in place. This creates an extremely compact module in which the occurrence of cavities and consequent damage to the module are effectively prevented.

According to a preferred second embodiment of the invention, the first solar cells protrude from one end of their group and the last solar cells protrude from the opposite, other end of their group, each lead band being transverse to the solar cells of each group and mutually connected in the overlap area with the protruding at one end or with the protruding back electrodes at the other end and is arranged outside the one end of each group formed by the solar cells except the first solar cells, or outside the other end formed by the solar cells except the last solar cells. Thus, the discharge tapes according to this second embodiment of the invention are outside the main part of the area of each group. This arrangement saves the application of an insulating layer on the solar cells, as is required in the case of the first embodiment of the invention. On the other hand, this involves a slight increase in the module area while the power has remained essentially constant. This embodiment therefore offers advantages in particular if there is a sufficiently large area available for installing the photovoltaic modules. 0

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

5 The inventive method according to the features of claim 12 offers the

Advantage that the individual groups can be easily applied to the back of a front film of the module. The subsequent parallel connection of the several groups ensures that the connection of the solar cells to one or more modules is shifted to the module assembly and thereby, in contrast to others

o Thin-film process, a simpler technology with fewer procedural individual steps can be used. The module size can be designed independently of the size of the solar cells. So-called scaling of the technical systems and special equipment for the production of the solar cells can be omitted. Due to the low number of individual technological steps, the manufacturing process can be relatively simple

^» 5 are carried out, which ultimately leads to a significant reduction in the solar electricity production costs. In addition, the application of so-called drain grids can be dispensed with according to the invention.

Advantageously, the front-side film is pulled off a roll and band-shaped solar cells with rear electrodes on top are applied transversely to the direction of advance of the front-side film, the front-side film preferably being heated before the solar cells are applied and the solar cells being overlapped with one another, the back electrode being the one Solar cell contacted the top electrode of the other, adjacent solar cell, inclined to the horizontal, are pressed into the front-side film. The method according to the invention can thus be carried out in a so-called roll-to-roll process. However, it is also possible to provide only one roll, ie the roll for the front-side film, and at the end of the process to separate the film into individual modules of the desired specifications. to cut the fication. The ribbon-shaped solar cells can also be pulled off a roll. Due to the mutual contacting of adjacent solar cells, these can be applied in a simple manner by superimposing the movement of the front-side film with that when the solar cell is being applied to the film. Due to the speed of the front foil, the solar cells are only a short distance in

Carrying direction of the film. This offers advantages in terms of the apparatus design of the method according to the invention.

According to another development of the invention, a strip-shaped electrical insulating layer is applied to 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 end except on the back electrode of the last solar cell, preferably on the back electrodes of each group are applied, preferably sprayed on, preferably in the area of the insulating layer, except in the contact areas via which the back electrodes of the first solar cell of each group or the back electrodes of the last solar cell of each group are to be electrically connected to one another. With the help of the application of the strip-shaped electrical insulating layer, a simple possibility is created to isolate the lead tape still to be applied from the other back electrodes of the respective group. This means that the electrical voltage is tapped only at those points which are appropriate for a particular purpose

Parallel connection of the individual groups is advantageous. Since the insulating layers and the hot-melt layers run essentially parallel to one another, on the one hand the insulating layers and on the other hand the hot-melt layers can be applied to the solar cells essentially simultaneously. This leads to an apparatus-compact device for carrying out the method and accelerates the carrying out of the method according to the invention for producing a module. In the sense of a double effect, the hot melt layer mentioned serves on the one hand to avoid voids in the module and on the other hand to fix the respective discharge band.

A lead tape is advantageously applied to the hot melt layers and the contact areas of the back electrodes of the first solar cell of each group or the contact areas of the back electrodes of the last solar cell of each group. The lead tape can thus run across the solar cells, which simplifies the application of the lead tape. Nevertheless, the discharge band only contacts certain back electrodes, insofar as this is technically necessary and sensible for the desired parallel connection. 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 are applied to the front-side film in such a way that the first solar cells in each case over one end of their group and the last solar cells in each case over the opposite, other end of their group protrude, the protruding portions of the first and the last solar cells being connected to each other with a lead tape. As previously stated in the explanation of the module according to the invention, the application of an insulating layer to the back electrodes of each group is unnecessary in this case.

Advantageously, the insulating layer, the hot melt layer, if present, and the discharge strips are applied transversely to the longitudinal direction of the solar cells or parallel to the direction of advance of the front-side film, which can further simplify the implementation of the method according to the invention, since there is the possibility of a movement mechanism for to completely dispense with the device for applying the insulating layer or the hot-melt layer.

According to a preferred development, the method according to the invention is a continuously running process, which means that the production of photovoltaic modules can be significantly accelerated.

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

1 shows a schematic bottom view of a first embodiment of a photovoltaic 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;

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

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

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;

7 shows a schematic, partial longitudinal section through a photovoltaic module near one end thereof 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.

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

Fig. 10 is a schematic bottom view of the module of FIG. 9 with part of the

Lead electrodes applied to back electrodes;

11 is a schematic bottom view of the photovoltaic module according to the first embodiment;

FIG. 12 shows a schematic bottom view of the photovoltaic module according to FIG. 11 with module junction box;

13 shows 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 a plurality of groups 2, 3, 4, 5 of series-connected solar cells 6, 7, 8, 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 in FIGS. 7 and 8 the front 10 of each photovoltaic module 1 is arranged at the bottom and the rear 11 of each photovoltaic module 1 at the top.

Each solar cell 6, 7, 8 has a cover electrode 12, a back electrode 13 and an absorber layer 14 between the electrodes 12, 13, these three elements in FIG. 7 with reference numerals for the sake of clarity only with regard to the solar cell 8 belonging to group 2 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 (CuInSe2) or copper indium disulfide (CuInS2). Other absorber layers, for example made of copper gallium diselenide (CuGaSe2), copper gallium disulfide (CuGaS2) and mixtures of these elements (Cu (In, Ga) (Se, S) 2), can also be used. This compound semiconductor

Groups Ib / HIa / NIa of the periodic table have a bandgap 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 capable of separating the light-generated charge carrier pairs, so that the charge carriers can be removed on the transparent, highly conductive cover electrode, also called the cover layer, or, as described according to the invention, 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 string 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 only three series-connected solar cells are shown in accordance with the representation of FIGS. 7 and 8. 3 to 6, a string can also consist, for example, of ten series-connected solar cells, and according to FIGS. 9 and 10 also nine series-connected solar cells, the number of series-connected solar cells depending on the desired voltage to be achieved, ie on the practical application , is largely predetermined and can vary within wide limits.

7 and 8, adjacent solar cells 6, 7 and 7, 8 are mutually overlapping such that the back electrode 13 of one solar cell 6 and 7, respectively

Cover electrode 12 of the other solar cell 7 or 8 contacted. 7 and 8 it can also be seen that the solar cells 6, 7, 8 are essentially flat and are each inclined to the horizontal.

According to the invention, the back electrodes 13 of the first solar cell 6 of each group are now

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, each lead tape 24, 25 being, as will be described in more detail later, perpendicular to the overlapping series-connected solar cells 6, 7, 8 of each group 2 to 5 is arranged.

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 is arranged near one end 26 (in FIG. 6 this is the upper end) of the back electrodes 13 and the other discharge band 25 is arranged near the opposite other end 27 (in FIG. 6 this is the lower end) of the back electrodes 13. 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.

7 and 8 it can also be seen that between the one lead band 24 and the back electrodes 13 of each group except the back electrode 13 of the first solar cell 6 and between the other lead band 25 and the back electrodes 13 of each group except the back electrode 13 the last solar cell 8 has an electrical insulation layer 30. 7 and 8 encompasses this insulating layer 30 in question standing solar cells, in the case of FIG. 7 the solar cells 7 and 8 and in the case of FIG. 8 the solar cells 6 and 7 shown in the right half approximately L-shaped, ie the insulating layer covers part of the underside, namely the rear electrode 13, each solar cell and the respective left end of the named 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, there is between the lead 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 in FIG. 7 and except in the contact area 32 in the case of 8 of the discharge belts with the first and last solar cells 6, 8, a hot melt layer 33 is provided. The hot melt layer can preferably also take on 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. The heat-activatable plastic is advantageously ethylene vinyl acetate (EVA) and thus the same plastic that is also used for embedding the module. Other plastics, in particular so-called hot melt adhesives such as macromelt 6208, can also be obtained from Henkel KG a.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 top 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 crosslinks at about 150 ° C. 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

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. However, it is also possible to form the latter layer, for example using 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. Non-transparent films or composite films, e.g. the products ICOSOLAR from ISOVOLTA are 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.

1, a ribbon-shaped solar cell 6 with an overhead rear electrode 13 is placed on a front side film 37 transversely to its longitudinal direction. The front-side film is shown in FIG. 1 merely as an example as a rectangular area. The front-side film 37 is preferably 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 then inclined to the horizontal (see also FIGS. 7 and 8) with mutual overlap (see also FIGS. 7 and 8) pressed into the front-side film 37, the rear electrode 13 of the one being shown in FIGS. 7 and 8 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 is very clearly shown in the illustration according to FIG. 2 in comparison to that of FIG. 1. It is clear that, as shown in FIGS. 7 and 8, adjacent solar cells overlap only slightly. There are now more connected to the solar cell 7 shown in FIG. 2

Solar cells on until finally the last solar cell 8 of this first group, which is given 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 that is partially 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. 4, the photovoltaic module 1 thus has four different groups 2 to 5, i.e. four strings 20 to 23 of series-connected 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

Trade endless face 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 5, electrical insulating layer 30 applied. Near the upper end 26, the solar module 1 has an insulating layer 30 on each group 2 to 5 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 and omitted in FIG. 6 for the sake of a better overview and illustration.

In a next method step, a lead tape 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

24, 25 applied. The device 15 according to the invention for connecting the plurality of groups 2 to 5 in parallel thus has according to the first, shown in FIGS. 1 to 8 and 11 to 14 Embodiment of the invention on a discharge tape 24, 25, which is either directly connected to the solar cells in the contact areas 31, 32 or indirectly lies 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 a bottom view in FIGS. 9 and 10.

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 respective first solar cells 6 over one end 26 of their group 2 to 5 and each last solar cells 8 protrude from the opposite, other end 27 of their group 2 to 5, the protruding 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 , 10, the discharge band 24 is spaced from one end 26 of the solar cells 7 and 8 and the opposite discharge band 25 from the opposite, other end 27 of the solar cells 6 and 7. In the case of

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 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, it also being possible for the strip-shaped solar cells 6, 7, 8 to be pulled off a roll and applied to the front-side film 37.

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. The photovoltaic module 1 thus produced is usually subjected to a frame 46, which is shown schematically in FIG. 13 (bottom view) with respect to the rear 11 of the module 1 and in FIG. 14 (top view) with respect to the front 10 of the module. Fig. 14 shows that the

Leads 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 several 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 several groups 2 to 5 by mutual connection on the one hand of the back electrodes 13 of the first solar cell 6 of each group 2 to 5 and on the other hand of the back electrodes 13 of the last solar cell 8 of each group 2 to 5,

Applying a film 43 forming the rear side 11 of the module 1 and, if necessary, laminating the film module.

The solar modules are preferably applied to the front-side film 37 or the rear-side film 43 is applied to the module by so-called lamination of the ribbon-shaped solar cells or the rear-side film.

According to the invention, the provision of special electrical outlets, also called discharge grids, can be completely dispensed with.

This makes it possible to produce a powerful photovoltaic module using a process that can be carried out in a simplified manner.

Claims

claims

1. Photovoltaic module with several groups (2, 3, 4, 5) each 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 an absorber layer (14) between the electrodes (12, 13), and with a device (15) for connecting the plurality of groups (2 to 5), characterized in 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 back electrode (13) of one solar cell (6, 7), the top electrode (12) of the other solar cell (7, 8) contacted.

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 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 discharge 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 other Ableitband (25) and the back electrodes (13) of each group (2 to 5) except the back electrode (13) of the last solar cell (8) 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 respective first or last solar cells (6 or 8) a hot melt layer (33) is provided.

10. Photovoltaic module according to claim 5 or 6, characterized in that the respective first solar cells (6) on one end (26) of their group (2 to 5) and the last solar cells (8) on the opposite, other end (27th ) of their group (2 to 5) and that each discharge band (24, 25) extends transversely to the solar cells (6, 7, 8) of each group.

5 pe (2 to 5) with mutual connection in the protruding area (34, 35) with the protruding at one end (26) or with the other end (27) protruding back electrodes (13) and outside of the solar cells except that in each case first solar cells (6) formed, one end (26) or outside the other end (27) or each group (2 to 5) formed by the solar cells (6, 7), except for 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). _: 5

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) 0 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 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);

- Application of a film (43) forming the rear side (11) of the module (1). 5

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 electrodes (13) are applied transversely to the direction of advance of the front side film (37). 0

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, the rear electrode (13) of a solar cell (6, 7th ) contacted the ceiling electrode (12) of the other, adjacent solar cell (7, 8), pressed into the front-side film (37) at an angle to the horizontal 5.

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 (6) and on the other hand near the opposite other end (27) except on the back electrode (13) of the

5 in each case last solar cell (8) a strip-shaped, electrical insulating layer (30) is applied.

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

10 contact areas (31, 32) over which the back electrodes (13) of the first solar cell (6) 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 electrically connected to each other, a hot melt layer I I (33) is applied.

15 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 (32nd ) of the back electrodes (13) of the last solar cell (8) of each group (2 to 5) a lead tape (24, 25) is applied.

20. 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 in such a way that the 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 ) project

25 and that the protruding sections (41, 42) of the first and the last respectively

Solar cells (6 or 8) are connected to each other with a lead tape (24, 25).

19. The method according to any one of claims 12 to 18, characterized in that the application of the insulating layer (30) and the hot melt layer (33), if present

30, 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 continuously running process.