DE102015114135A1 - Photovoltaic device and method for producing a photovoltaic device - Google Patents

Abstract

The present invention relates to a photovoltaic device (1) and a method for producing a photovoltaic device (1). The photovoltaic device (1) has a substrate (17) with a large main area (H) on which at least two solar cells (3a, 3b, 3c) connected in series along a boundary are arranged adjacent to one another, the two solar cells (3a , 3b, 3c) each have a back contact layer (25a, 25b, 25c), a transparent conductive layer (19a, 19b, 19c) and an optically active layer (15, 15a, 15b, 15c, 21, 21a, 21b, 21c, 23rd , 23a, 23b, 23c), the series connection comprising a contacting (11b, 11c) of the back contact layer (25a, 25b) of a first solar cell (3a, 3b) of the two solar cells (3a, 3b, 3c) with the transparent conductive layer (FIG. 19b, 19c), a second solar cell (3b, 3c) of the two solar cells (3a, 3b, 3c), wherein the contacting (11b, 11c) parallel to the large major surface (H) of the substrate (17) as a two-dimensional grid of individual Contacts (11a, 11b, 11c) is formed.

Description

The present invention relates to a photovoltaic device according to the preamble of claim 1 and to a method of manufacturing a photovoltaic device according to the preamble of claim 7.

Such photovoltaic devices usually consist of a plurality of solar cells each having at least one optically active layer, which are interconnected with each other. In this case, the contact layer on the light entry side is preferably formed as a transparent conductive layer (TCO), which, however, still has a comparatively poor conductivity in order to allow the highest possible light transmission. Frequently, therefore, a series connection is chosen to keep resistance-related power losses small. As a result, the current is introduced on one side into the respective solar cell.

Such a series connection can be achieved by a process control with three different structuring steps P1, P2, P3, for example in the form of LASER structuring lines. In the context of a so-called superstrate construction of the solar cell, the TCO layer, which acts as a front contact layer, is severed, for example, in the first structuring step (P1). In the second patterning step (P2), an opening and subsequent connection is made between the front contact and back contact layers, and in the third structuring step (P3), the back contact layer is severed such that the monolithically formed layers comprise first and second adjacent solar cells within a photovoltaic device Form (solar module), wherein the front contact of a solar cell to the back contact of the adjacent solar cell are connected, the back contact of the one, however, is formed electrically isolated from the front contact of the other solar cell.

However, there are disadvantages with this concept. On the one hand, the asymmetrical current injection has a negative influence on the leakage line (P = R × l ² ). On the other hand, the area between the P1 and P3 structuring lines is not available to the charge carrier generation. In addition, the series connection of the individual cells leads to undesirably high operating voltages, which must be compensated by complex parallel circuits, which interconnections cause further efficiency losses due to passive contacting cells.

To improve was in the WO 2014/152556 A1 proposed for the Superstrataufbau, instead of the three structuring steps P1, P2, P3 make only two structuring steps, wherein an insulating step is carried out for the isolation of adjacent solar cells, with which the back contact layer, the optically active layer and the TCO layer are severed. In addition, a contacting step is carried out in which the back contact layer and the optically active layer are severed and the TCO layer is connected to the back contact layer of an adjacent solar cell. These contacts are placed in the middle of the respective solar cell. As a result, the dead area can be reduced because there is no area between P1 and P3. In addition, the negative effects of asymmetric current injection are avoided, since the current injection now takes place symmetrically, which reduces the series resistance, since the current now only has to travel halfway through each solar cell.

The object of the present invention is to further increase the efficiency of photovoltaic devices. In particular, the dead area should be reduced.

This object is achieved with the photovoltaic device according to the invention according to claim 1 and the inventive method for producing a photovoltaic device according to claim 7. Advantageous developments are specified in the dependent subclaims and the description.

The inventors have recognized that the stated object can be solved in a surprising manner particularly simple if there is no linear contact between two adjacent solar cells, as previously, especially in the WO 2014/152556 A1 is taught, but a two-dimensional contact is made, with a two-dimensional grid of individual contacts forms the surface contact.

Thus, on the one hand, the distances between two adjacent solar cells can be substantially increased so that the dead areas caused by the solar cell separation can be reduced. While previously the solar cell width, so the distance between two insulation between adjacent solar cells was 5 mm to 15 mm, it can now be for example 30 mm. On the other hand, the series resistances are further reduced because the current path through the respective cell is further reduced.

The photovoltaic device according to the invention with a substrate having a large main surface, on which at least two solar cells connected in series along a boundary are arranged adjacent to one another, wherein the two solar cells each have a back contact layer, a transparent one conductive layer and an optically active layer, wherein the series connection has a contacting of the back contact layer of a first solar cell of the two solar cells with the transparent conductive layer of a second solar cell of the two solar cells, thus characterized by the fact that the contact parallel to the large main surface of the Substrate is designed as a two-dimensional grid of individual contacts.

In an advantageous development, the grid is formed regularly, preferably with a lateral distance between two adjacent contacts of 1 to 20 mm, preferably 3 to 10 mm, in particular 4 to 7 mm. This significantly reduces the series resistance. Although rasters of less than 1 mm are possible, but this lithography process is required, which is relatively expensive, which is why this embodiment is not preferred.

In a further advantageous development, the individual contacts are punctiform in cross section, preferably with a cross-sectional width of at most 500 μm, preferably at most 300 μm, in particular at most 200 μm. As a result, the dead areas can be significantly reduced. Preference is given in particular to contact with the smallest possible dimension in the range 1 μm to 100 μm, preferably 50 μm to 10 μm, in particular 15 μm.

The shape of the contacts is preferably square, circular, rectangular or elliptical.

In a further advantageous development, the width of the solar cells perpendicular to the boundary between the solar cells is at least 3 mm, preferably at least 15 mm, in particular at least 39 mm. In this case, widths of up to 100 mm, preferably of up to 600 mm, in particular of up to 1000 mm and beyond are possible.

In a further advantageous development, the contacting of the front contact layer of the second solar cell with the back contact layer of the first solar cell is in a conductive connection. From the back contact layer of the second solar cell, which is insulated via an insulation layer, the front contact layer preferably forms individual contacts extending vertically with the transparent conductive layer. As a result, the contacting can be made particularly simple and reliable.

In this connection, it is advantageous if the insulation layer extends between the front contact layer and the optically active layer, since then short circuits can be effectively prevented. This is advantageous above all for the superstrate construction, but the substrate construction can be dispensed with.

The method according to the invention for producing a photovoltaic device having a substrate with a large main area, on which at least two solar cells connected in series along a boundary are arranged adjacent to one another, the two solar cells each having a back contact layer, a transparent conductive layer and an optically active layer wherein the series connection has a contacting of the back contact layer of a first solar cell of the two solar cells with the transparent conductive layer of a second solar cell of the two solar cells, characterized in that the contact is formed parallel to the large main surface of the substrate as a two-dimensional grid of individual contacts.

In an advantageous development, it is provided that the back contact layer is uniformly applied to all solar cells and then removed in the region of the individual contacts to be produced, the removal preferably taking place by means of LASER irradiation. As a result, the contact is particularly easy.

In a further advantageous development it is provided that a removal of the back contact layer and the optically active layer takes place up to the transparent conductive layer, wherein no vertical structuring, but a relation to the vertical inclined structuring is made. Then, the insulating layer to be applied for contacting the transparent conductive layer by means of a planar exposure process through the transparent conductive layer can be reopened very simply and inexpensively, without exact alignment being required and without the edge insulation being lost. The inclination of the structuring edge formed is preferably either 0.1 ° to 30 °, preferably 3 ° to 20 °, in particular 12 ° to 19 ° relative to the normal of the main surface, because then the edge insulation can easily close again, for example, by using a lacquer Gravity conditionally trailing, or at angles of 70 ° to 89 °, preferably 75 ° to 85 °, in particular 78 ° to 82 °, the surface insulation can not be damaged during planar exposure.

In a further advantageous embodiment, it is provided that at the boundary between two solar cells, a transection of a conductive layer near the substrate and a separation of a substrate-distant conductive layer is made, the separation preferably as P1 and P3 or P1, P2 and P3 Structuring steps or as a uniform, continuous isolation step is made and in particular as LASER structuring.

In a further advantageous embodiment it is provided that the photovoltaic device according to the invention is produced.

In a further advantageous development it is provided that the transparent conductive layer, above the optically active layer, above the back contact layer, above an insulating layer and above a front contact layer are arranged on the substrate, wherein the boundary between two adjacent solar cells by a transection of the transparent conductive Layer and the back contact layer is formed, wherein after application of the back contact layer with a patterning step, the back contact layer and the optically active layer are each locally removed to form a respective contact, after application of the insulation layer these locally at the locations of the respective contacts is removed again and between the Contacts and the boundary between two solar cells, the insulating layer is removed by forming a third structuring trench, after application of the front contact layer in a structuring step along de The boundary is so structured that the front contact layer has a direct conductive connection with the back contact layer towards the boundary and there is no direct conductive connection to the back contact layer in the direction of the contacts, wherein it is preferably provided that the optically active layer is applied before the back contact layer is applied and the transparent conductive layer are removed in a patterning step along the boundary between two solar cells and the formed first structuring trench is filled with an insulating material and after the back contact layer has been applied, the back contact layer is removed in a structuring step along the boundary between two solar cells and the second structuring trench formed with the material of the insulation layer is filled. However, here as well, a P1, P2, P3 structuring or a structuring with a uniformly continuous isolation step could alternatively be carried out. As a result, the invention can be realized in superstrate construction.

In a further advantageous development it is provided that a front contact layer, above an insulating layer, above the back contact layer and above the optically active layer are arranged on the substrate, wherein the boundary between two adjacent solar cells is formed by a transection of the front contact layer and the transparent conductive layer wherein, after application of the front contact layer, this is removed along the boundary between two solar cells to form a first pattern trench which is filled with material of the insulating layer, after the insulation layer is removed along the boundary between two solar cells, to form a second pattern trench forming the second pattern trench adjacent to the first pattern trench and filling with material of the back contact layer, after applying the back contact layer with a patterning step, the R ckkontaktschicht is locally removed to form each contact, before application of the transparent conductive layer, the optically active layer and the insulating layer are removed locally at the locations of the respective contacts, after application of the transparent conductive layer, this is removed in a structuring step between two solar cells to form a third structuring trench, which is preferably filled with an insulating material. However, here as well, a P1, P2, P3 structuring or a structuring with a uniformly continuous isolation step could alternatively be carried out. As a result, the invention can be realized in the substrate structure.

The characteristics and further advantages of the invention will become apparent in the context of the following description of a preferred embodiment in conjunction with the figures. Here are purely schematic:

1a and 1b the photovoltaic device according to the invention according to a first preferred embodiment in a plan view from above and in a sectional view of this,

2 the photovoltaic device according to the invention 1 in a partial sectional view,

3a to 3e the sequence of steps for the preparation of the photovoltaic device according to the invention according to 1 .

4 the step after 3d in an alternative embodiment,

5a and 5b partial sectional views of alternative insulation between individual solar cells,

6a to 6d an alternative sequence of steps for the production of the photovoltaic device according to the invention according to a second preferred embodiment,

7 the photovoltaic device according to the invention according to a third preferred embodiment in a partial sectional view and

8th the photovoltaic device according to the invention according to a third preferred embodiment in a partial sectional view.

In 1a and 1b is the photovoltaic device according to the invention 1 according to a first preferred embodiment of the above shown purely schematically. 2 shows a partial sectional view corresponding 1b ,

It can be seen that the device 1 numerous solar cells 3 in Superstrataufbau, so for the introduction of sunlight through the substrate, comprises, which are arranged strip-shaped side by side, wherein these are connected in series with each other. More precisely, it is 30 solar cells 3 , each having a length l of 585 mm and a width b of 39.5 mm. By means of the junction box 5 that with the first solar cell 3 ' and the last solar cell 3 '' is connected, the generated current can be tapped, with a current of 6.2 A at a voltage of 25 V is reached. It can be seen that in comparison to previous solutions no complex parallel connection is required.

In 1b is for three freely selected solar cells 3a . 3b . 3c , which are directly next to each other with the interposition of respective insulation 7a . 7b are arranged, the contacting of the solar cells 3a . 3b . 3c shown purely schematically among each other. It can be seen that every solar cell 3a . 3b . 3c a two-dimensional grid regularly over the main surface H of each solar cell 3a . 3b . 3c distributed arranged first, with "+" shown contacts 11a . 11b . 11c and a second contact 13a . 13b . 13c , which is shown here for convenience only as a plurality of "-", but is actually formed as a contact line. Here are the first contacts 11a . 11b . 11c a further left solar cell 3a . 3b . 3c each with the second contacts 13a . 13b . 13c a respective right next to the arranged solar cell 3a . 3b . 3c about the respective insulation 7a . 7b electrically connected, while the first contacts 11a . 11b . 11c from the second contacts 13a . 13b . 13c the same solar cell 3a . 3b . 3c are isolated, so that the current flow through the solar cell 3a . 3b . 3c over the optically active layer 15a . 15b . 15c must be done.

The further layer structure of the solar cells 3a . 3b . 3c is appropriate 2 the following, for the sake of simplicity, not all first contacts 11a . 11b . 11c are shown: on a transparent substrate 17a . 17b . 17c For example, a glass substrate, a transparent conductive layer (TCO) 19a . 19b . 19c For example, tin oxide on which a cadmium sulfide layer 21a . 21b . 21c and then a cadmium telluride layer 23a . 23b . 23c are arranged on it there is a back contact layer 25a . 25b . 25c , an insulation layer 27a . 27b . 27c and a front contact layer 29a . 29b . 29c ,

The cadmium sulfide layer 21a . 21b . 21c and the cadmium telluride layer 23a . 23b . 23c form the optically active layer 15a . 15b . 15c , which can consist however of only one layer or also of more than two layers. Furthermore, one or more buffer layers, for example for the passivation of defects, can also be provided in the layer structure shown. For example, the transparent conductive layer 19a . 19b . 19c consist of several layers, in particular of two sub-layers, the actual transparent conductive layer and a buffer layer. In addition, the back contact could also 25a . 25b . 25c be constructed of several layers, in particular of two sub-layers, the actual back contact and a buffer layer.

The individual layers of the solar cells each lie as uniformly monolithically deposited layers 19 . 21 . 23 . 25 . 27 . 29 in part, from the contacting structuring 31 as well as the P1- 33 and the P3 structuring 35 are interrupted. The respective adjacent P1- 33 and P3 structuring 35 form the insulation 7a . 7b between the solar cells 3a . 3b . 3c and the contacting structuring 31 form the grid-shaped arranged first contacts 11a . 11b . 11c , The second contacts 13a . 13b each consist of electrically conductive connections between the back contact layers 25a . 25b the leftmost solar cell 3a . 3b with the front contact layers 29b . 29c the respective solar cells arranged to the right thereof 3b . 3c ,

In the 3a to 3a is the sequence of steps for the production of the photovoltaic device according to the invention 1 shown, for the sake of simplicity, only the region of a first contact 11 shown with a second contact arranged adjacent 13 becomes.

It can be seen that the individual layers 19 . 21 . 23 successively deposited monolithically on the glass substrate. Subsequently, a first patterning trench is formed by LASER irradiation 31 generated, which extends in a line parallel to the length l, and with a suitable electrical insulation material 33 , For example, a suitable paint, is filled, whereby the P1 structuring is generated. The structuring trench 31 is aware of something in the glass substrate 17 inserted in order to achieve optimum insulation.

After application of the back contact layer 25 becomes a second one by means of LASER irradiation structuring ditch 35 which extends in a line parallel to the length I, for some optimal electrical insulation something in the cadmium telluride layer 23 into it.

In 3b It can be seen that by LASER irradiation local structures in the form of square hole-like depressions 37 5 mm wide and perpendicular to the length l, the spacing of the depressions being approximately 5 mm and the width of the depressions 37 at the transition to the TCO layer 19 be about 50 microns. These depressions 37 (for the sake of clarity, is in 3b to 3e only one depression 37 shown) penetrate in contrast to the second structuring trench 35 but not the TCO layer 19 , In addition, the edges run 39a . 39b the wells 37 not parallel to the surface normal of the large main surface H but with an inclination α of 0.1 ° to 30 °, preferably 3 ° to 20 °, in particular 12 ° to 19 ° or 70 ° to 89 °, preferably 75 ° to 85 °, in particular 78 ° to 82 °.

Corresponding 3c becomes an electrical insulation layer 27 applied in the form of a dielectric, which forms the second structuring trench 35 filled and thereby formed the P3 structuring. And it becomes the surface of the ground 47 the wells 37 covered.

As in 3d can be seen, the applied insulation layer 27 exposed from both sides 41 . 43 once by means of a mask (not shown) from above, around the insulation layer 27 between the P1, P3 structuring and the wells located directly to the left thereof 37 parallel to the length l in the context of a third structuring trench 45 away. In addition, by exposure from below 43 the insulation layer at the bottom 47 the wells 37 locally removed. By the inclination α of the edges 39a . 39b the wells 37 the exposure takes place only at the bottom 47 so the edges 39a . 39b the wells 37 continue from the insulation layer 27 stay covered. Optionally, for the insulation layer 27 a varnish can be used, which runs after something, so that also to the reason 47 adjacent areas of the edges 39a . 39b the wells 37 safe with the insulation layer 27 stay covered. Due to the inclination α, therefore, no exactly aligned exposure by means of a matched mask is required, but a large-area exposure is sufficient 43 from the bottom, which makes the production much easier and cheaper. After appropriate development is then a cured insulation layer 27 in front.

In conclusion, it will be accordingly 3e the front contact layer 29 applied using a mask (not shown) to be in the area 49 no contacting of the back contact layer 25 manufacture. At the same time, the second contact forms 13 out, which is the back contact layer 25a the left solar cell 3n with the front contact layer 29b the right next arranged solar cell 3n + 1 electrically conductive connects. At the bottom 47 the wells 37 contacts the front contact layer 29a the TCO layer 19a the left solar cell 3n in the form of a first contact 11 ,

As substrates 17 For example, float glass, soda lime glass, polymers and other suitable materials may be considered. As a transparent conductive layer 19 are tin oxide, zinc oxide, cadmium stannate, their doped variants, combinations of these materials and other suitable materials. As an optically active layer 15 For example, one or more n-type and / or one or more p-type semiconductors forming a pn junction (or alternatively a pin junction) are contemplated. In the present case, n-type cadmium sulfide 21 and p-type cadmium telluride 23 prefers. The back contact layer 25 can be just like the front contact layer 29 one of the materials comprises aluminum, chromium, gold, copper, molybdenum, nickel, palladium, silver, titanium, tungsten or combinations thereof or other suitable materials. The aforementioned layers 15 . 19 . 21 . 23 . 25 . 29 are preferably deposited by a sputtering process, but other suitable methods are possible. As insulation layer 27 hardenable paints and other suitable materials in question, which can be applied for example by an ink jet printing process, but also by sputtering or a roller coater can be applied.

As a result, there is a series connection of the solar cells 3n . 3n + 1 via the insulation formed by means of the P1, P3 structures 7 time. On the other hand, the current through the device 1 over the two-dimensional grid of first contacts 11 conducted, so that only very small resistance losses occur and at the same time the dead areas are minimized.

More specifically, the solar cells 3 a width b of 39.5 mm compared to a width of 5 mm used in conventional devices. Also the device of WO 2014/152556 A1 has a width of 5 mm. So on the overall width of the device 1 of 1185 mm 30 solar cells 3 while conventional devices each have 237 solar cells. It follows that in the device according to the invention 1 only 29 insulations 7 In contrast, conventional devices have 236 isolations. The width of the P1, P2 and P3 structuring is usually about 50 μm in each case, the respective structuring trenches each being approx. 25 microns must be spaced. Also the isolation structuring of WO 2014/152556 A1 has such a width. Thus, the dead area for insulation with insulation structuring is 50 μm wide, in a P1, P3 structuring about 50 μm + 25 μm + 50 μm = 125 μm wide and in a P1, P2, P3 structuring about 50 μm + 25 μm + 50 μm + 25 μm + 50 μm = 200 μm wide. The total dead area width is thus approximately 200 .mu.m.times.236 = 47,200 .mu.m in a conventional device with P1, P2, P3 structuring, and approximately 50 .mu.m.times.236 = 11,800 .mu.m in the case of a conventional device with insulation structuring and in the device according to the invention 1 with P1, P2, P3 structuring about 200 μm × 29 = 5,800 μm, with P1, P3 structuring about 125 μm × 29 = 3,625 μm and with an insulation structuring about 50 μm × 29 = 1,450 μm. The dead area can thus be reduced by the inventive design by at least about 50% and up to about 87%. This is an efficiency gain of at least about 0.1% abs, a maximum of about 0.8% abs compared to devices with P1, P2, P3 structuring connected. The gain in efficiency over devices with insulation structuring is at least about 0.1% abs and at the maximum about 1.4% abs.

Continue to lie the first contacts 11 as square points of about 50 .mu.m to 150 .mu.m in side length, wherein the distance of the contacts with each other and to the insulation 7 each about 5 mm. This is compared to conventional devices with P1, P2, P3 structuring an efficiency gain of at least about 0.2% abs, a maximum of about 1.0% abs compared to devices with P1, P2, P3 structuring connected.

Overall, the efficiency can be increased by up to 2.0% abs compared to conventional devices with P1, P2, P3 structuring, ie. H. by two to six power classes 2.5 W. But also compared to the conventional solution with insulation structuring, the efficiency can be increased by up to 1.0% abs, d. H. by three power classes 2.5 W.

In 4 is an alternative to the manufacturing step after 3d shown. There is no areal exposure 43 from below, but the exposure 51 takes place through a mask (not shown) or as LASER point exposure from above. This can cause the covering of the ground 47 adjacent areas of the edges 39a . 39b the wells 37 with the insulation layer 27 also be ensured. However, this requires a higher alignment effort.

In the 5a and 5b are alternative embodiments of the insulation 7 ' . 7 '' between two solar cells 3n . 3n + 1 shown. It can be seen that the insulation 7 ' in 5a is designed as classic P1, P2, P3 structuring, while the isolation 7 '' as isolation structuring accordingly WO 2014/152556 A1 was produced.

In the 6a to 6d FIG. 10 is an alternative sequence of steps for manufacturing the photovoltaic device according to the invention. FIG 100 shown in more detail according to a second preferred embodiment.

It can be seen that the initial steps are identical here (cf. 6a and 3b ). After introduction of the second structuring trench 35 and the wells 37 However, an intermediate step takes place (cf. 6b ), in which the back contact layer 25 in the area 101 is removed again locally. Alternatively, the application of the back contact layer could 25 also be done with the help of an appropriate mask, so that the areas 101 to be left out. After subsequent application of the insulation layer 103 (see. 6c ) and the front contact layer 105 (see. 6d ) under selective recess of the area 107 according to the comments on 3c to 3e here is a larger horizontal spacing between back contact layer 25 and front contact layer 105 protects against short-circuits even more effectively.

In 7 is the photovoltaic device according to the invention 150 represented according to a third preferred embodiment in a partial sectional view.

It can be seen that the device 150 Numerous solar cells in the substrate structure, ie for the introduction of sunlight opposite from the substrate, comprises, which are arranged in strips next to each other, wherein these are connected in series with each other. For the sake of clarity, compared to the 1 to 2 only two solar cells 151n . 151n + 1 shown and only a first contact 153 ,

This device 150 was made by placing on a glass substrate 155 a front contact layer 157 deposited and then a P1 structuring was made. Then it was used as insulation layer 159 applied a dielectric in the form of a paint, exposed and developed, so that the P1 structuring filled and the P2 structuring were formed. Subsequently, the back contact layer 161 applied and locally by means of a LASER structuring in the area 162 away. Thereafter, the optically active layer 163 and a buffer layer 165 applied and the buffer layer 165 , the optically active layer 163 , the back contact layer 161 and the insulation layer 159 were further enhanced with a LASER patterning with a smaller diameter than the previous LASER structuring Front contact layer 157 removed to pits 167 form, wherein the back contact layer of the wells 167 through the optically active layer 163 is disconnected. By applying the TCO layer 169 becomes the front contact layer 157 contacted. Finally, the TCO layer 169 , the buffer layer 165 , the optically active layer 163 , the back contact layer 161 and a part of the insulation layer 159 in a P3 structuring step and the structuring trench that forms 171 is optionally filled with an electrical insulator (not shown).

In the 8th in a partial sectional view of the invention shown photovoltaic device 200 according to a third preferred embodiment is different from the device 150 to 7 in that the LASER structuring for generating the area 162 in 7 instead after the LASER patterning step to create the pits 167 and before application of the TCO layer 201 another insulation layer 203 applied and so exposed and cured that this insulating layer substantially only vertically at the edges 205a . 205b the wells 167 is present, the reason 207 the wells 167 However, partially uncovered, so there is the TCO layer 201 the front contact layer 157 can contact. The back contact layer 209 and the optically active layer 211 border directly to the further insulation layer 203 at.

From the foregoing, it has become clear that with the present invention, the efficiency of photovoltaic devices 1 . 100 . 150 . 200 can be significantly improved. There are no dead contacting cells and except for the two connections for the junction box 5 to the contact cells 3 ' . 3 '' No additional contact strips and silver conductive adhesive are required. For the described surface of the device 1 of 585 mm × 1185 mm, power of 6.2 A × 25 V can now be achieved. Due to the significantly lower number of solar cells 3 and thus isolations 7 The throughput can be significantly increased because the number of structuring steps is significantly reduced.

Defects in the devices 1 . 100 . 150 . 200 can be subsequently easily removed, for example by cutting, laser scanning or burnout, with supportive imaging techniques, such as electroluminescence, thermography or photoluminescence can be used to locate these defects.

Unless otherwise indicated, all features of the present invention may be freely combined with each other. The features described in the description of the figures can, unless stated otherwise, be freely combined with the other features as features of the invention. Objective features can also be used as process features and process features as representational features.

LIST OF REFERENCE NUMBERS

1

Photovoltaic device according to the first preferred embodiment

3

Solar cells in superstrat construction

3a, 3b, 3c

solar cells

3 '

first solar cell

3 ''

last solar cell

3n, 3n + 1, 3n + 2

adjacently arranged solar cells

5

junction box

7a, 7b

Insulations between adjacent solar cells 3a . 3b . 3c

11, 11a, 11b, 11c

first contacts, "+"

13, 13a, 13b, 13c

second contacts, "-"

15, 15a, 15b, 15c

optically active layer

17, 17a, 17b, 17c

optically transparent substrate, glass substrate

19, 19a, 19b, 19c

transparent conductive layer (TCO), tin oxide

21, 21a, 21b, 21c

Cadmium sulfide layer

23, 23a, 23b, 23c

Cadmium telluride layer

25, 25a, 25b, 25c

Back contact layer

27, 27a, 27b, 27c

insulation layer

29, 29a, 29b, 29c

Front contact layer

31

Contact-structuring

33

P1-structuring

35

P3-structuring 35a . 35b

37

local structuring in the form of square hole-like depressions

39a, 39b

Edges of the recesses 37

41, 43

exposure

45

third structuring trench

47

Reason of the depressions 37

49

Area of the front contact layer

51

exposure

7 ', 7' '

Isolation between two solar cells 3n . 3n + 1

100

Photovoltaic device according to the second preferred embodiment

101

Area of the back contact layer 25

103

insulation layer

105

Front contact layer

107

Area

150

Photovoltaic device according to the third preferred embodiment

151n, 151n + 1

adjacent solar cells in the substrate structure

153

first contact

155

glass substrate

157

Frontaktaktschicht

159

insulation layer

161

Back contact layer

162

Area of the back contact layer 161

163

optically active layer

165

buffer layer

167

wells

169

TCO layer

171

structuring ditch

200

Photovoltaic device according to the third preferred embodiment

201

TCO layer another

203

insulation layer

205a, 205b

Edges of the recesses 167

207

Reason of the depressions 167

209

Back contact layer

211

optically active layer

l

Length of the solar cells 3

b

Width of the solar cells 3

α

Inclination of the edges 39a . 39b

H

Main surface of the substrate 17

N

Normal of the main surface H

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2014/152556 A1 [0005, 0008, 0048, 0048, 0052]

Claims (13)

Photovoltaic device ( 1 ) with a substrate ( 17 ) having a large main area (H) on which at least two solar cells connected in series along a boundary ( 3a . 3b . 3c ) are arranged adjacent to each other, wherein the two solar cells ( 3a . 3b . 3c ) each have a back contact layer ( 25a . 25b . 25c ), a transparent conductive layer ( 19a . 19b . 19c ) and an optically active layer ( 15 . 15a . 15b . 15c . 21 . 21a . 21b . 21c . 23 . 23a . 23b . 23c ), wherein the series connection is a contacting ( 11b . 11c ) of the back contact layer ( 25a . 25b ) of a first solar cell ( 3a . 3b ) of the two solar cells ( 3a . 3b . 3c ) with the transparent conductive layer ( 19b . 19c ) a second solar cell ( 3b . 3c ) of the two solar cells ( 3a . 3b . 3c ), characterized in that the contacting ( 11b . 11c ) parallel to the major major surface (H) of the substrate ( 17 ) as a two-dimensional grid of individual contacts ( 11a . 11b . 11c ) is trained. Photovoltaic device ( 1 ) according to claim 1, characterized in that the grid is formed regularly, preferably with a lateral distance between two adjacent contacts ( 11a . 11b . 11c ) of 1 to 20 mm, preferably 3 to 10 mm, in particular 4 to 7 mm. Photovoltaic device ( 1 ) according to claim 1 or 2, characterized in that the individual contacts ( 11a . 11b . 11c ) are punctiform in cross-section, preferably formed with a cross-sectional width of at most 500 microns, preferably at most 300 microns, in particular at most 200 microns. Photovoltaic device ( 1 ) according to one of the preceding claims, characterized in that the width (b) of the solar cells ( 3a . 3b . 3c ) perpendicular to the boundary between the solar cells ( 3a . 3b . 3c ) is at least 3 mm, preferably at least 15 mm, in particular at least 39 mm. Photovoltaic device ( 1 ) according to one of the preceding claims, characterized in that the contacting ( 11a . 11b . 11c ) a front contact layer ( 29b . 29c ) of the second solar cell ( 3b . 3c ) which is in contact with the back contact layer ( 25a . 25b ) of the first solar cell ( 3a . 3b ) is in conductive connection and from the back contact layer ( 25b . 25c ) of the second solar cell ( 3b . 3c ) via an insulating layer ( 27b . 27c ), wherein the front contact layer ( 29b . 29c ) preferably with the transparent conductive layer ( 19b . 19c ) vertically extending individual contacts ( 11b . 11c ) trains. Photovoltaic device ( 1 ) according to claim 5, characterized in that the insulating layer ( 27b . 27c ) between front contact layer ( 29b . 29c ) and optically active layer ( 15b . 15c ). Method for producing a photovoltaic device ( 1 ) with a substrate ( 17 ) having a large main area (H) on which at least two solar cells connected in series along a boundary ( 3a . 3b . 3c ) are arranged adjacent to each other, wherein the two solar cells ( 3a . 3b . 3c ) each have a back contact layer ( 25a . 25b . 25c ), a transparent conductive layer ( 19a . 19b . 19c ) and an optically active layer ( 15 . 15a . 15b . 15c . 21 . 21a . 21b . 21c . 23 . 23a . 23b . 23c ), wherein the series connection is a contacting ( 11b . 11c ) of the back contact layer ( 25a . 25b ) of a first solar cell ( 3a . 3b ) of the two solar cells ( 3a . 3b . 3c ) with the transparent conductive layer ( 19b . 19c ) a second solar cell ( 3b . 3c ) of the two solar cells ( 3a . 3b . 3c ), characterized in that the contacting ( 11b . 11c ) parallel to the major major surface (H) of the substrate ( 17 ) as a two-dimensional grid of individual contacts ( 11a . 11b . 11c ) is formed. Method according to claim 7, characterized in that the back contact layer ( 25a . 25b . 25c ) uniform for all solar cells ( 3a . 3b . 3c ) and then in the region of the individual contacts ( 11a . 11b . 11c ), the removal preferably being by LASER irradiation. A method according to claim 7 or 8, characterized in that a removal of the back contact layer ( 25a . 25b ) and the optically active layer ( 15a . 15b . 21a . 21b . 23a . 23b ) to the transparent conductive layer ( 19a . 19b ) is carried out, wherein an inclined relative to the vertical structuring is made, wherein the inclination (α) of the structuring edge formed ( 39a . 39b ) preferably either 0.1 ° to 30 °, preferably 3 ° to 20 °, in particular 12 ° to 19 ° or 70 ° to 89 °, preferably 75 ° to 85 °, in particular 78 ° to 82 ° relative to the normal (N) the major surface (H) is. Method according to one of claims 7 to 9, characterized in that at the border ( 7a . 7b . 7c ) between two solar cells ( 3a . 3b . 3c ) a transection of a substrate-near conductive layer ( 19a . 19b . 19c ) and a transection of a substrate-remote conductive layer ( 25a . 25b . 25c ), wherein the separation is preferably as P1- ( 31 ) and P3- ( 35 ), in particular as P1, P2 and P3 LASER structuring steps. Method according to one of claims 7 to 10, characterized in that the photovoltaic device ( 1 ) is produced according to one of claims 1 to 6. Method according to one of claims 7 to 11, characterized in that on the substrate ( 17 ) the transparent conductive layer ( 19 above) the optically active layer ( 15 . 21 . 23 ), above the back contact layer ( 25 ), above an insulation layer ( 27 ) and above a front contact layer ( 29 ), the limit ( 7a . 7b . 7c ) between two adjacent solar cells ( 3a . 3b . 3c ) by a transection of the transparent conductive layer ( 19 ) and the back contact layer ( 25 ) is formed, wherein after application of the back contact layer ( 25 ) with a structuring step the back contact layer ( 25 ) and the optically active layer ( 15 . 21 . 23 ) each locally ( 37 ) to form one contact each ( 11a . 11b . 11c ) after application of the insulating layer ( 27 ) these locally ( 47 ) at the locations of the respective contacts ( 11a . 11b . 11c ) is removed again and between the contacts ( 11a . 11b . 11c ) and the border ( 7a . 7b . 7c ) between two solar cells ( 3a . 3b . 3c ) the insulation layer ( 27a . 27b . 27c ) by forming a third structuring trench ( 45 ) is removed, after application of the front contact layer ( 29 ) in a structuring step ( 49 ) along the border ( 7a . 7b . 7c ) is structured so that the front contact layer ( 29a . 29b . 29c ) towards the border ( 7a . 7b . 7c ) a direct conductive connection with the back contact layer ( 25a . 25b . 25c ) and in the direction of the contacts ( 11a . 11b . 11c ) no direct conductive connection to the back contact layer ( 25a . 25b . 25c ), wherein it is preferably provided that, before application of the back contact layer ( 25 ) the optically active layer ( 15 . 21 . 23 ) and the transparent conductive layer ( 19 ) in a structuring step ( 31 ) along the border ( 7a . 7b . 7c ) between two solar cells ( 3a . 3b . 3c ) and the formed first structuring trench ( 31 ) with an insulating material ( 33 ) and after application of the back contact layer ( 25 ) the back contact layer ( 25 ) in a structuring step ( 35 ) along the border ( 7a . 7b . 7c ) between two solar cells ( 3a . 3b . 3c ) and the formed second structuring trench ( 35 ) with the material of the insulating layer ( 27 ) is filled. Method according to one of claims 7 to 11, characterized in that on the substrate ( 155 ) a front contact layer ( 157 ), above an insulation layer ( 159 ), above the back contact layer ( 161 ; 209 ) and above the optically active layer ( 163 ; 211 ), wherein the boundary between two adjacent solar cells is separated by a transection of the front contact layer (FIG. 157 ) and the transparent conductive layer ( 169 ; 201 ) is formed, wherein after application of the front contact layer ( 157 ) is removed along the boundary between two solar cells to form a first structuring trench (P1) which is coated with material of the insulating layer (P1). 159 ) after application of the insulating layer ( 159 ) is removed along the boundary between two solar cells to form a second structuring trench (P2), wherein the second structuring trench (P2) is arranged adjacent to the first structuring trench (P1) and coated with material of the back contact layer (P2). 161 ; 209 ) is filled, after application of the back contact layer ( 161 ; 209 ) with a structuring step the back contact layer ( 161 ; 209 ) each locally ( 162 ) to form one contact each ( 153 ) is removed prior to application of the transparent conductive layer ( 169 ; 201 ) the optically active layer ( 163 ; 211 ) and the isolation layer ( 159 . 203 ) local ( 167 ) at the locations of the respective contacts ( 153 ) are removed after application of the transparent conductive layer ( 169 ; 201 ) in a structuring step ( 171 ) is removed between two solar cells to form a third structuring trench (P3), which is preferably filled with an insulating material.

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