Adjusting the field width of cells within a photovoltaic element

Abstract

The present invention relates to a photovoltaic element (1) having n cells (3) arranged on a substrate (27), from a first cell (3) to an nth cell (3), wherein: - the cells (3) each have a base electrode (5), a cover electrode (7) and a layer system (9) having at least one photoactive layer (10), the layer system (9) being arranged between the base electrode (5) and the cover electrode (7); - the cells are interconnected in series; and - the photovoltaic element (1) has at least one busbar (11) connected to the first cell (3) and / or the nth cell (3) by means of conductive contacts (13). The conductive contact (13) of at least one busbar (11) to the cover electrode (7) of the first cell (3) and / or the cover electrode (7) of the nth cell (3) is made by via points (17) arranged at a specific distance A (15), preferably a periodic distance (15), from one another in the longitudinal direction of the busbar (11). In the areas between the individual via points (17), no conductive contact (13) is made between the cover electrode (7) and the at least one busbar (11). A surrounding area (19) around the via points (17) in a surrounding circle having a diameter of less than A / 2, preferably less than A / 4, is not photoactive, or is at least photoactive to a lesser extent.

Description

[Technical Field]

[0001] The present invention relates to a photovoltaic element comprising n cells arranged on a substrate, from a first cell to an nth cell, wherein each cell has a lower electrode, an upper electrode, and a layer system comprising at least one photoactive layer, the layer system being positioned between the lower electrode and the upper electrode, and the cells being interconnected in series with each other, and the photovoltaic element having at least one busbar connected to the first cell and / or the nth cell by conductive contacts. [Background technology]

[0002] Optoelectronics comprises the fields of optics and semiconductor electronics. It particularly includes systems and methods that enable the conversion of electrically generated energy into light or light into energy. Optoelectronic components, especially photovoltaic elements such as organic photovoltaic elements (OPVs) and organic light-emitting diodes (OLEDs), generate electrical energy or convert electrical energy into light, which must then be induced outside or inside the optoelectronic component for application. Current is usually transmitted externally by busbars attached to the edges of electrodes. For contact, a junction box is placed in the area of ​​the busbars of the photovoltaic element.

[0003] Organic photovoltaic elements consist of a series of thin layers, each containing at least one photoactive layer, which are preferably deposited by vapor deposition under vacuum or fabricated from a solution. Electrical links can be realized by metal layers, transparent conductive oxide films, and / or transparent conductive polymers. Vacuum deposition of organic layers is particularly advantageous in the manufacture of multilayer solar cells, especially tandem or triple cells.

[0004] Photovoltaic elements have a layered structure comprising multiple layers. This layered structure typically includes electrode layers, particularly those made of conductive transparent materials, a transparent conductive metal oxide (TCO), one or more photoactive layers, and electrode layers. In the case of transparent or translucent photoactive elements, both electrodes may be metal. Possible configurations of the layered systems of photovoltaic elements are described in International Publication Nos. 2004083958A2 and International Publication Nos. 2011138021A2.

[0005] Organic photovoltaic elements can be fabricated, for example, by material deposition, polymer printing, or processing from liquid. The basic configuration of organic photovoltaic elements is described in International Publication Nos. 2004083958 and 2011138021. Organic photovoltaic elements are constructed by laser processing. These methods are also used, in particular, to interconnect individual photovoltaic cells on optoelectronic components and to electrically insulate the photovoltaic cells. Due to the limited conductivity of the layer system and to adapt the output voltage and output current of the photovoltaic element, the photovoltaic element, i.e., the layer system of the photovoltaic element, is usually subdivided into cells that are arranged adjacent to each other, and these are interconnected in series. In this case, the width of such cells is usually in the range of a few millimeters to a few centimeters.

[0006] A conventional solution for solar cells, especially organic solar cells, which is particularly important with respect to mechanical and chemical damage, is to connect busbars across the entire width or at least short via points to each cell. Such via points, and especially single-sided contact solar cells including via points, are known from the prior art.

[0007] European Patent No. 2033228B1 discloses a single-sided contact solar cell comprising at least one absorber layer configured with vias and an emitter layer made of a semiconductor material, wherein the emitter layer is arranged over the entire area of ​​one side of the absorber layer, and excess charge carriers are collected by two contact systems jointly arranged on one side of the absorber layer and dissipated into the absorber layer, the contact systems being electrically in contact externally and insulated from each other.

[0008] European Patent No. 2466640A2 discloses a thin-film photovoltaic module which is subdivided into a plurality of photovoltaic cells electrically connected in series in an integrated manner by separation lines that cut at least one layer of the layered structure of the thin-film photovoltaic module, at least two of the separation lines extending non-parallel to each other, at least one portion of the separation line being part of a series of interconnection strips interconnecting two adjacent photovoltaic cells in series, and at least one of the separation lines cutting all layers of the thin-film photovoltaic module and insulating two adjacent photovoltaic cells from each other.

[0009] This prior art similarly discloses cells of different formats on a photovoltaic element, where these cells have the same area.

[0010] German Utility Model No. 202007010590U1 discloses a solar module comprising a plurality of interconnected individual solar cells having the same area, with transparent or translucent regions provided between the solar cells, and providing at least two different formats of solar cells.

[0011] Since the current generated in a photovoltaic element cell is proportional to the cell's area, a partially damaged or malfunctioning cell will generate a smaller current, and in the case of cells connected in series, the current of the photovoltaic element is determined by the cell with the lowest current, especially the cell with the smallest area.

[0012] Electrical connections between the first or last cell in a module containing series-connected cells and their respective busbars are particularly problematic. Firstly, the connections often result in the formation of localized damage within the photoactive layer system, which occurs, for example, as a result of mechanical stress when a conductive pressure-sensitive adhesive (PSA) containing metal particles is pressed and / or chemical damage when a conductive adhesive is used. Secondly, electrical connections between cells, which are intended to be protected from moisture and atmospheric oxygen in a sealed state as much as possible, and busbars, which are typically located outside the sealed area, are critical in terms of the intrusion of moisture and atmospheric oxygen, mainly in relation to the barrier layer or sealant.

[0013] Therefore, a disadvantage of the prior art is that the cells beneath the busbar are photovoltaically completely or at least nearly inactive, i.e., they do not contribute to the module's efficiency. This leads to significant losses in efficiency, especially when relatively wide busbars, for example, wider than 1 cm, are required, such as when attempting to discharge current from very long modules. [Overview of the project] [Problems that the invention aims to solve]

[0014] Therefore, the present invention is based on the objective of providing a photovoltaic element in which the above-mentioned drawbacks do not occur or are at least mitigated, the harmful effects of busbars on cells containing such busbars are minimized, and a photovoltaic element with higher efficiency and / or longer lifespan is obtained. [Means for solving the problem]

[0015] This objective is achieved by the subject matter of the independent claim. Advantageous embodiments will become apparent from the dependent claims.

[0016] This objective is achieved, in particular, by providing a photovoltaic element comprising n cells arranged on a substrate, from a first cell to an nth cell, each cell having a lower electrode, an upper electrode, and a layer system comprising at least one photoactive layer, the layer system being positioned between the lower electrode and the upper electrode, and the cells interconnected in series with each other, and the photovoltaic element having at least one busbar connected to the first cell and / or the nth cell by conductive contact. The conductive contact of at least one busbar with the upper electrode of the first cell and / or the upper electrode of the nth cell is formed in each case by via points arranged from each other at a specific distance A, preferably at a periodic distance, in the longitudinal direction of the busbar, and in the region between the individual via points, no conductive contact is formed between the upper electrode and at least one busbar, and the surrounding region around the via points in an enclosing circle having a diameter of less than A / 2, preferably less than A / 4, is not photoactive or is at least photoactive to a reduced degree.

[0017] According to the present invention, the first cell and / or the nth cell are conductively connected to at least one busbar by via points, so-called vias. Preferably, the conductive contact between at least one busbar and the first cell or the nth cell is not present throughout the entire length, but rather at via points that are at a specific distance A from each other. Preferably, at least one busbar is not conductively connected to the upper electrode along the entire length of the cell.

[0018] In one preferred embodiment of the present invention, the photoactive regions of the first and / or nth cells under at least one busbar are sufficiently large compared to the 2-n-1 cells, thereby ensuring that the current generation of the first and / or nth cells under at least one busbar is at least as large as that of the other cells interconnected in series with the photovoltaic elements, preferably the width of the first and / or nth cells under at least one busbar is increased compared to the 2-n-1 cells.

[0019] Therefore, preferably, as a result of the increased area, in particular the increased width, of the first cell and / or the n-th cell compared to the 2nd to (n-1)-th cells, the efficiency before aging is somewhat higher, whereby it is ensured that each of said cells does not become a current-limiting cell among the series-interconnected cells of the photovoltaic element, even if the deterioration of said cell is accelerated due to the intrusion of moisture into the first cell and / or the n-th cell under the busbar.

[0020] In one preferred embodiment of the present invention, the lower electrode, the layer system and the upper electrode are structured by a laser. In one preferred embodiment of the present invention, the individual cells of the photovoltaic element are interconnected in series with each other by laser structuring.

[0021] In one preferred embodiment of the present invention, the upper electrode and / or the lower electrode comprises silver or a silver alloy, aluminum or an aluminum alloy, gold or a gold alloy, or a combination of these materials, a conductive oxide, particularly ITO, ZnO, ZnO:Al, SnO2 or any other TCO (transparent conductive oxide), a conductive polymer, particularly PEDOT / PSS (poly(3,4-ethylenedioxythiophene)-poly(styrene sulfonate)) or PANI (polyaniline). Furthermore, the upper electrode and / or the lower electrode may have a network structure of metal nanowires or metal nanoparticles, and the metal is preferably silver, copper or gold.

[0022] In one preferred embodiment of the present invention, the lower electrode is disposed on a substrate, particularly a thin film.

[0023] It should be understood that a photovoltaic element refers to a photovoltaic cell, particularly a solar cell. The photovoltaic device is preferably composed of a plurality of photovoltaic cells that can be interconnected in series or in parallel. The plurality of photovoltaic cells can be arranged and / or interconnected in various ways within the photovoltaic device.

[0024] In one preferred embodiment of the present invention, at least one via point is formed in a point, linear, or grid pattern. In one preferred embodiment of the present invention, the via point is 1 cm 2 The area less than or equal to the area preferably contains multiple smaller via points in a circular or rectangular pattern. This is particularly advantageous when the contact resistance of the via points varies with the total length of the edge rather than with the area.

[0025] In one preferred embodiment of the present invention, via points are formed at a distance of at least 2 cm, preferably at least 5 cm, preferably at least 10 cm, or preferably at least 20 cm, between the first and / or nth cell and at least one busbar.

[0026] A busbar should be understood to mean an arrangement that is electrically connected to take-in and take-out lines, along with at least one lower electrode and / or at least one upper electrode, particularly for the purpose of electrical contact as a central distributor of electrical energy. At least one busbar is electrically contacted at least partially by the lower electrode or the upper electrode. Busbars are formed planarly, particularly as ribbons, strips, plates, or metal layers.

[0027] In one preferred embodiment, the layer thickness of at least one busbar is 10 μm to 500 μm, preferably 100 μm to 500 μm, preferably 10 μm to 200 μm, preferably 10 μm to 100 μm, preferably 10 μm to 50 μm, or preferably 20 μm to 40 μm.

[0028] In one preferred embodiment of the present invention, at least one busbar is formed from a metal or an alloy thereof, preferably copper and tin.

[0029] The term "organic photovoltaic element" should be understood to mean a photovoltaic element that includes at least one organic photoactive layer, particularly a polymer-organic photovoltaic element or an organic photovoltaic element based on small molecules. The photoactive layer may form an acceptor-donor system and may include multiple individual layers or mixed layers.

[0030] Small molecules should be understood as nonpolymeric organic molecules that exist in the solid phase at standard pressure (ambient atmospheric pressure) and room temperature, particularly with a monodisperse molar mass of 100-2000 g / mol. In particular, small molecules are photoactive, meaning that when exposed to incident light, the molecule changes its charge state and / or orientation state. An advantage of these absorber materials based on small molecules is their evaporability in a vacuum.

[0031] In one preferred embodiment of the present invention, at least one photoactive layer of the layer system contains small molecules that can be evaporated in a vacuum. In one preferred embodiment of the present invention, at least one photoactive layer of the layer system is deposited by vapor deposition under vacuum.

[0032] In one preferred embodiment of the present invention, the area of ​​the first cell and / or the nth cell is greater than the area of ​​2 to n-1 cells in each case.

[0033] In one preferred embodiment of the present invention, at least one busbar is conductively in contact with an electrode of a cell having higher surface conductivity, and the sheet resistance of the electrode with higher conductivity is less than 10 ohms per square, preferably less than 1 ohm per square, or preferably 0.1 ohms per square.

[0034] In one preferred embodiment of the present invention, the upper electrode of the cell is a more conductive electrode, and the lower electrode of the cell is a less conductive electrode, preferably the sheet resistance of the less conductive electrode is less than 10 ohms per square, preferably less than 1 ohm per square.

[0035] In one preferred embodiment of the present invention, the photovoltaic element comprises at least one cell including at least one photoactive layer, particularly a CIS cell, CIGS cell, GaAs cell or Si cell, a perovskite cell or an organic photovoltaic element (OPV), a so-called organic solar cell.

[0036] In one preferred embodiment of the present invention, the photovoltaic element has a layer system comprising at least two photoactive layers, in which case the photovoltaic element is a tandem cell, and preferably has a layer system comprising at least three photoactive layers, in which case the photovoltaic element is a triple cell.

[0037] In one preferred embodiment of the present invention, at least one busbar is positioned in the longitudinal direction L of one cell.

[0038] The longitudinal direction L of a cell should be understood to mean the direction in which the cell, particularly in the case of a photovoltaic element, has the longest range.

[0039] Preferably, multiple cells arranged side-by-side on a substrate of the photovoltaic element are interconnected in series.

[0040] The photovoltaic element according to the present invention has advantages over the prior art. Advantageously, damage to the first and / or nth cells by at least one busbar, particularly the resulting inductive area loss, is compensated by the larger extent of the first and / or nth cells. Advantageously, even if degradation occurs at the via points of the first and / or nth cells, particularly if moisture and / or oxygen penetrates, the fully functional area of ​​the first and / or nth cells with the busbars is still maintained. Advantageously, the first and / or nth cells with at least one busbar can continue to generate at least the same level of photocurrent as the other cells for a longer lifetime. Advantageously, further damage to the cells is at least partially prevented by the structuring lines and / or separation lines. Advantageously, the number of via points through which moisture can penetrate into the cell, or the total area of ​​via points, is reduced. Advantageously, the function of the photovoltaic element is maintained, particularly even if the photovoltaic element undergoes relatively significant aging. Advantageously, the efficiency of the photovoltaic element can be improved. An advantage is that the lifespan of the photovoltaic element is extended.

[0041] According to one evolution of the present invention, each of the n cells has a specific width B and a specific length L in each case, the first cell and / or the nth cell has a larger width B than the 2 to n-1 cells, and the n cells each have the same length L, preferably the n cells from the first cell to the nth cell are arranged relative to each other along their longitudinal sides, and / or the areas of the 2 to n-1 cells are the same size as each other, so that the photocurrent generation of the first cell and / or the nth cell, when uniformly illuminated from a surface of the photovoltaic element facing away from at least one busbar, is at least the same size as the 2 to n-1 cells, preferably at least 5% larger, preferably at least 10% larger, or preferably at least 20% larger. Preferably, the photocurrent generation of the cell is related to the aging of the cell, i.e., aging as a result of mechanical load, contact with oxygen in the atmosphere, contact with moisture, and / or time until the start of aging.

[0042] In one preferred embodiment of the present invention, 2 to n-1 cells have the same width and the same length.

[0043] According to one advanced form of the present invention, a protective layer, preferably a protective film, having mechanical protection, oxygen barrier, and / or moisture barrier functions, is positioned between at least one busbar and the upper electrodes and / or layer system of a cell, preferably a first cell and / or an nth cell, which is at least partially perforated in the surrounding area around the via points. In one preferred embodiment of the present invention, at least one protective layer forms a encapsulant of the photovoltaic element.

[0044] The protective layer should be understood to mean a barrier layer, particularly for preventing external influences, especially oxygen and / or moisture from passing through, a protective layer and / or filter layer, preferably a UV filter, for increasing mechanical durability, especially scratch resistance.

[0045] In one preferred embodiment, the thickness of at least one protective layer is 250 nm to 500 nm, preferably 250 nm to 100 μm, preferably 250 nm to 100 μm, or preferably 100 μm to 200 μm, preferably 10 μm to 100 μm, preferably 10 μm to 50 μm, or preferably 20 μm to 40 μm.

[0046] In one preferred embodiment of the present invention, the protective layer is an SiOCH layer between the cell and the busbar, and via points are formed through the SiOCH layer between the cell and the busbar.

[0047] In one preferred embodiment of the present invention, the length of the cell is at least twice the width of the cell, preferably at least five times, preferably at least ten times, preferably at least twenty times, preferably at least fifty times, preferably at least one hundred times, or preferably at least one thousand times.

[0048] In one preferred embodiment of the present invention, the optoelectronic component is in contact with at least one busbar by conductive contact from the side intended to be opposite the sun.

[0049] In relation to the present invention, the side of the photovoltaic element opposite to the sun should be understood as the back surface of the photovoltaic element that is not the side intended to face the incident light. Therefore, in the present invention, the side of the photovoltaic element facing the sun should be understood as the front surface of the photovoltaic element that is the side intended to face the incident light.

[0050] According to one evolution of the present invention, the first cell has a width B smaller than that of 2 to n cells, and the n cells each have the same length L, and the first cell is preferably at least substantially photoactive or electrically bridged.

[0051] In one preferred embodiment of the present invention, the cell width-to-length ratio is 1:10 to 1:1000, preferably 1:10 to 1:500, preferably 1:10 to 1:300, preferably 1:10 to 1:100, preferably 1:100 to 1:1000, preferably 1:100 to 1:500, or preferably 1:10 to 1:300.

[0052] In one preferred embodiment of the present invention, the cells are arranged on the substrate facing downwards, at least substantially parallel to one another.

[0053] In one preferred embodiment of the present invention, the cross-sectional area of ​​the via point is 0.1 to 100 mm². 2 Preferably 0.1 to 25 mm 2 Preferably 0.2 to 10 mm 2 Preferably 0.2 to 1 mm 2 Preferably 1-2 mm 2 Or preferably 1 to 1.5 mm 2 That is the case.

[0054] In one preferred embodiment of the present invention, via points are formed at a distance of at least 1 cm from each other in the longitudinal direction of the busbar, preferably at least 2 cm from each other, preferably at least 5 cm from each other, preferably at least 10 cm from each other, or preferably at least 20 cm from each other.

[0055] In one preferred embodiment of the present invention, the width B of cells 2 to n-1 is 0.5 cm to 5 cm, preferably 1 cm to 5 cm, and / or the length L of cells 1 to n is 10 cm to 20 m, preferably 20 cm to 10 m, or preferably 50 cm to 5 m.

[0056] In one preferred embodiment of the present invention, the width B of the first cell and / or the nth cell is increased by at least 5%, preferably at least 10%, preferably at least 20%, or preferably at least 25%, compared to the 2 to n-1 cells, thereby increasing the photocurrent generation of the first cell and / or the nth cell by at least 5%, preferably at least 10%, or preferably at least 20%, compared to the 2 to n-1 cells, when uniformly illuminated from the surface of the photovoltaic element facing away from at least one busbar.

[0057] In one preferred embodiment of the present invention, either the lower or upper electrode in the peripheral region around a via point is electrically insulated from the respective electrodes of the rest of the layer system of the first and / or nth cell by a closed structuring line, preferably a circular or rectangular structuring line, in each case, so that the shunt current path between the lower and upper contacts in the peripheral region around the via point does not result in a short circuit of the corresponding first and / or nth cell. As a result, damage to the cells, particularly the first and / or second cell, by the shunt current path between the lower and upper electrodes does not result in a short circuit relating to the first and / or nth cell under at least one busbar.

[0058] In one preferred embodiment of the present invention, either the lower electrode or the upper electrovoid within the via point region is electrically insulated from the other electrode by a structuring line.

[0059] In one preferred embodiment of the present invention, either the lower electrode or the upper electrode in the surrounding area around a via point is electrically insulated from the respective electrodes in the rest of the layer system of the first and / or the nth cell by a closed structuring line, preferably a circular or rectangular structuring line, in each case, so that the shunt current path between the lower electrode and the upper electrode in the surrounding area around the via point does not result in a short circuit of the first and / or the nth cell.

[0060] A structured line should be understood as a surface curve that electrically insulates the layer system between each electrode within the surrounding area around a via point and each electrode outside the surrounding area around the via point, particularly from the lower or upper electrode, preferably one of the two electrodes is electrically insulated, and the structured line is formed horizontally with respect to the layer system along the entire circumference of the via point together with the surrounding area around the via point, and vertically with respect to the layer system by only one selected from the lower or upper electrode, preferably supplementarily, as a whole or at least partially, through the layer system. In a plan view, the surface curve appears as a straight line or a curve. Structured lines are formed particularly by laser ablation.

[0061] In one preferred embodiment of the present invention, the surrounding area around the via point does not have a layer system including a photoactive layer, or at least does not have a layer system including a complete photoactive layer, and preferably the via point does not have a layer system including a photoactive layer.

[0062] According to one evolution of the present invention, in each case, the layer system of cells in the region surrounding the via point is made to have, at the via point, additional separation lines that at least partially prevent the diffusion of moisture that has penetrated into the layer system outside the region surrounding the via point. The separation lines are preferably formed by laser ablation, and preferably the separation lines 25 spatially coincide with or lie within the region defined by the structuring lines 23 of the lower electrode 5 or the upper electrode 7.

[0063] The separation line should be understood to mean the line that spatially separates the layer system from the via point, along with the surrounding region around the via point within the boundary provided by the structuring line, and the separation line is formed horizontally with respect to the layer system along the entire circumference of the via point, along with the surrounding region around the via point, and vertically with respect to the layer system, formed at least partially through the layer system by the entire layer system, so that at least one or both electrodes of the layer system are at least substantially held. The separation line is formed in particular by laser ablation.

[0064] Photovoltaic cells are classified as single, tandem, or multicell depending on the number of photoactive layer systems, which are determined by the transport layer and other layers in the layer configuration between the lower and upper contacts. Tandem and multicell cells consist of at least two subcells arranged in a stacked manner between the electrodes, with each subcell containing at least one photoactive layer system.

[0065] In one preferred embodiment of the present invention, the layer system has at least two photoactive layers, in which case the photovoltaic cell is a tandem cell, and preferably comprises at least three photoactive layers, in which case the photovoltaic cell is a triple cell.

[0066] In one preferred embodiment of the present invention, the layer system further comprises at least one charge carrier transport layer, the at least one charge carrier transport layer being located between a lower electrode or an upper electrode and a photoactive layer, preferably comprising at least a first charge carrier transport layer and a second charge carrier transport layer, the first charge carrier transport layer being located between a lower electrode and at least one photoactive layer, and the second charge carrier transport layer being located between at least one photoactive layer and an upper electrode.

[0067] In one preferred embodiment of the present invention, the photovoltaic element has at least one inactive region, i.e., a layer system, in particular a photoactive layer, which is deactivated in particular by the corresponding laser structuring, preferably a first cell being deactivated.

[0068] In one preferred embodiment of the present invention, the first cell of the photovoltaic element is either deactivated or not interconnected in series with the other 2 to n cells.

[0069] According to one advanced form of the present invention, the photovoltaic element is a photovoltaic thin film element, preferably an organic photovoltaic thin film element and / or a flexible photovoltaic thin film element, the photovoltaic thin film element preferably having at least one photoactive layer composed of small molecules as an absorbent material.

[0070] In one preferred embodiment of the present invention, the photovoltaic element is an organic photovoltaic element, preferably a flexible organic photovoltaic element, and preferably, at least one photoactive layer of the organic photovoltaic element contains small molecules as an absorbent material.

[0071] A flexible photovoltaic element should be understood to mean a photovoltaic element that is bendable and / or stretchable, especially in a specific region.

[0072] In one preferred embodiment of the present invention, the photovoltaic element has at least a first busbar and a second busbar, the first busbar being connected to a first cell by a first conductive contact, and the second busbar being electrically connected to an nth cell by a second conductive contact.

[0073] In one preferred embodiment of the present invention, the photovoltaic element has a junction box, and at least one busbar is electrically connected to the junction box. The junction box is understood to mean an element for connecting the photovoltaic element to an external electrical circuit. In one preferred embodiment of the present invention, a first busbar and a second busbar are electrically connected to the junction box.

[0074] The present invention will be described in more detail below with reference to the following drawings. [Brief explanation of the drawing]

[0075] [Figure 1]A schematic side view of an exemplary embodiment of a cell layer system of a photovoltaic element is shown. [Figure 2] A schematic side view of an exemplary embodiment of a photovoltaic element including a plurality of cells connected in series with conductive contacts is shown. [Figure 3] A schematic plan view of an exemplary embodiment of a photovoltaic element including a plurality of cells connected in series with conductive contacts including via points arranged at a distance A from each other is shown. [Figure 4] A schematic plan view of an exemplary embodiment of a photovoltaic element including a plurality of cells connected in series with conductive contacts including via points arranged at a distance A from each other is shown. [Figure 5] A schematic plan view of an exemplary embodiment of a photovoltaic element including a plurality of cells connected in series with conductive contacts including via points arranged at a distance A from each other is shown. DETAILED DESCRIPTION OF EMBODIMENTS

[0076] Figure 1 is a schematic side view of an exemplary embodiment of a configuration of a cell 3 of a layer system 9 of a photovoltaic element 1.

[0077] In this exemplary embodiment, the photovoltaic element 1 consists of a cell 3 formed of a series of thin films including a photoactive layer 10, which is preferably deposited by vapor deposition under vacuum or processed from a solution. Electrical links, that is, contact means, are realized by metal layers, transparent conductive oxides and / or transparent conductive polymers. The configuration of such a cell 3 including the layer system 9 is shown in Figure 1.

[0078] In this exemplary embodiment, the cell 3 of the photovoltaic element 1 includes a lower electrode 5, in particular a transparent lower electrode 5, made of, for example, ITO, arranged on a substrate 27 made of, for example, glass. The layer system 9 is formed thereon, said layer system including fullerene C 60 an electric transport layer 20 including, at least one absorber material and fullerene C 60The layer system 9 includes a photoactive layer 10 and an electron transport layer 22 composed of di-NPB and NDP 9. An upper electrode 7 made of gold is placed on top of it. The layer system 9 and / or electrodes 5, 7 are structured by a laser. The layer system 9 may also have another hole injection layer, hole transport layer, photoactive layer and / or electron transport layer. The relative sizes of the cell 3, the layers of the layer system 9 and the substrate 27 are not shown by precise scale.

[0079] The structuring of individual layers and electrodes can be achieved, for example, by laser ablation, electron or ion beam ablation, mechanical scribing, or shadow masking. As a result, holes and / or slots are created in the layer system 9, for example, which serve to allow the lower electrode 5 to pass through the layer system 9, thereby forming via points between electrodes 5 and 7 (P2 structuring). Further structuring within the lower electrode 5 (P1 structuring) and the upper electrode 7 (P3 structuring) is required for the series interconnection of cells within the optical activator. Furthermore, a structuring line is obtained surrounding the complete cell 3 composed of electrodes 5 and 7 and the layer system 9 (P4 structuring).

[0080] Figure 2 is a side view schematic of one exemplary embodiment of a photovoltaic element 1, which includes a plurality of series-connected cells 3 having conductive contacts. The same and functionally identical elements are given the same reference numerals; therefore, please refer to the above description in this regard.

[0081] The photovoltaic element 1 in this exemplary embodiment is a photovoltaic element 1 that utilizes thin-film technology.

[0082] The photovoltaic element 1 has n cells 3 arranged on a substrate 27, from the first cell 3 to the nth cell 3, each cell 3 having a lower electrode 5, an upper electrode 7, and a layer system 9 including at least one photoactive layer 10, the layer system 9 being positioned between the lower electrode 5 and the upper electrode 7, and the cells 3 being interconnected in series with each other. The photovoltaic element 1 has at least one busbar 11 connected to the first cell 3 and / or the nth cell 3 by conductive contacts 13. The conductive contact of at least one busbar 11 with the upper electrode 7 of the first cell 3 and / or the upper electrode 7 of the nth cell 3 is formed in each case by via points 17 located at a specific distance A15, preferably a periodic distance 15, from each other in the longitudinal direction of the busbar 11. In the region between the individual via points 17, no conductive contact is formed between the upper electrode 7 and at least one busbar 11. In the surrounding circle having a diameter of less than A / 2, preferably less than A / 4, the surrounding area 19 around the via point 17 is either not photoactive or at least reduced to a certain extent. In this exemplary embodiment, the lower electrode 5, the upper electrode 7 and the layer system 9 are laser-structured for the purpose of forming cells 3 and interconnecting cells 3 in series. In this case, in one embodiment of the present invention, at least one busbar 11 is formed of aluminum or tin and copper.

[0083] In this exemplary embodiment, a protective layer 21, preferably a protective thin film, is positioned between at least one busbar 11 and the upper electrode 7 and / or cell 3, preferably the first and / or nth cell 3 layer system 9, which has mechanical protection, oxygen barrier and / or moisture barrier functions, and is at least partially perforated in the surrounding area 19 around the via point 17.

[0084] In this exemplary embodiment, the cell 3 corresponding to the first cell 3 located on the left has a smaller width B compared to the other cells 3 (2 to n), the cell 3 corresponding to the nth cell 3 located on the right has a larger width B compared to the other cells (1 to n-1), and each of the central cells 3 (2 to n-1) has the same width B. As a result, since each of the cells 3 has the same length, the area of ​​the first cell 3 of the photovoltaic element 1 is the smallest, and the area of ​​the nth cell 3 of the photovoltaic element 1 is the largest. In this exemplary embodiment, the first cell 3 is not integrated into a series interconnection, i.e., the first cell 3 does not contribute to photovoltaic generation, and therefore its area can be minimized.

[0085] In this exemplary embodiment, the layer system 9 has one photoactive layer 9, but alternatively, the layer system may have two, three, or four photoactive layers 10.

[0086] In this exemplary embodiment, the width B of the first cell 3 of the photovoltaic element 1 is smaller than the widths of the 2 to n-1 cells 3 and is therefore not deactivated by the corresponding laser structuring or interconnected in series with the other 2 to n cells 3. As a result, the first cell 3, having a smaller area, does not limit the overall power of the photovoltaic element 1. In the alternative embodiment, the first cell 3 has a larger width B than the 2 to n-1 cells 3, particularly a width B corresponding to the width B of the nth cell 3, is activated, and interconnected in series with the other 2 to n cells 3. In this embodiment, the larger area of ​​the first cell 3 compared to the 2 to n cells 3 does not have a limiting effect on the overall power of the photovoltaic element 1.

[0087] As a result, damage to the first and / or nth cells by at least one busbar, particularly the resulting loss of functional area, is compensated for by the larger extent of the first and / or nth cells. Even with moisture intrusion at via points, sufficient functional area of ​​the first and / or nth cells with busbars is still maintained. Advantageously, the lifespan of the photovoltaic element is extended.

[0088] In one embodiment of the present invention, each of the n cells 3 has a specific width B and a specific length L in each case, the first cell 3 and / or the nth cell 3 has a larger width B than the 2 to n-1 cells 3, and the n cells 3 each have the same length L, preferably the n cells 3 from the first cell 3 to the nth cell 3 are arranged relative to each other along their longitudinal sides, and / or the areas of the 2 to n-1 cells 3 are the same size as each other, thereby the photocurrent generation of the first cell 3 and / or the nth cell 3 when uniformly illuminated from the opposite side of at least one busbar 11 of the photovoltaic element 1 is at least the same size as the 2 to n-1 cells 3, preferably at least 5% larger, preferably at least 10% larger, or preferably at least 20% larger.

[0089] In another embodiment of the present invention, the first cell 3 has a smaller width B compared to 2 to n cells 3, and the n cells 3 each have the same length L, and the first cell 3 is preferably at least substantially photoactive or electrically bridged. Preferably, the first cell 3 is not included in the series interconnection, or the first cell 3 is electrically bridged and therefore does not have a current limiting effect with respect to the series interconnection.

[0090] In another embodiment of the present invention, the first cell 3 is not a complete cell but includes a lower electrode 5 or an upper electrode 7, and is an electrode having higher surface conductivity, particularly selected from the lower electrode 5 and the upper electrode 7.

[0091] In another embodiment of the present invention, the busbar 11 of the first cell 3 is formed to have a greater width than the first cell 3, so that at least a portion of the busbar 11 rests on the second cell 3, but is electrically insulated from the second cell 3 by the protective layer 21.

[0092] In another embodiment of the present invention, via points 17 are formed at a distance of at least 1 cm 15 from each other in the longitudinal direction of the busbar 11, preferably at least 2 cm from each other, preferably at least 5 cm from each other, preferably at least 10 cm from each other, or preferably at least 20 cm from each other.

[0093] In another embodiment of the present invention, the width B of cells 3 2 to n-1 is 0.5 cm to 5 cm, preferably 1 cm to 5 cm, and / or the length L of cells 1 to n is 10 cm to 20 m, preferably 50 cm to 20 m, and / or the width B of the first cell 3 and / or the nth cell 3 is made at least 5%, preferably at least 10%, preferably at least 20%, or preferably at least 25%, larger than that of cells 2 to n-1, thereby increasing the photocurrent generation of the first cell 3 and / or the nth cell 3 when uniformly illuminated from the surface of the photovoltaic element 1 facing away from at least one busbar 11, by at least 5%, preferably at least 10%, or preferably at least 20%, compared to cells 2 to n-1.

[0094] In another embodiment of the present invention, the lower or upper electrode in the surrounding area 19 around the via point 17 is electrically insulated from the respective electrodes 5, 7 of the rest of the layer system of the first cell 3 and / or the nth cell 3 by a closed structuring line 23, preferably a circular or rectangular structuring line 23, in each case, so that the shunt current path that occurs between the lower contact 5 and the upper contact 7 in the surrounding area 19 around the via point 17 does not result in a short circuit of the corresponding first cell 3 and / or the nth cell 3.

[0095] In another embodiment of the present invention, within the region of the structuring line 23 adjacent to the lower electrode 5 or the upper electrode 7, the layer system 9 is also interrupted, either entirely or at least partially, thereby preventing or at least reducing the diffusion of moisture and / or atmospheric oxygen in the surrounding area 19 around the via point 17, particularly lateral diffusion.

[0096] In another embodiment of the present invention, the surrounding region 19 around the via point 17 does not have a layer system 9 including the photoactive layer 10 in each case, or does not have at least a layer system 9 including the photoactive layer 10, and preferably the via point 17 does not have a layer system 9 including the photoactive layer 10.

[0097] In another embodiment of the present invention, the layer system 9 of cell 3 has additional separation lines 25 in each case within the surrounding area 19 around the via point 17, i.e., in the region around the via point 17, which at least partially prevents the diffusion of moisture that has penetrated into the layer system 9 outside the surrounding area 19 around the via point 17 at the via point 17. As a result, further damage to the cell is at least partially prevented. In one embodiment of the present invention, the separation lines 25 can be made to coincide with the structural lines 23 of the lower electrode 5 or the upper electrode 7, or can be located within the region defined by the structural lines 23, and can have a smaller diameter in particular compared to the structural lines 23.

[0098] In another embodiment of the present invention, the photovoltaic element 1 is a photovoltaic thin film element, preferably an organic photovoltaic thin film element and / or a flexible photovoltaic thin film element, and the photovoltaic thin film element preferably has at least one photoactive layer 10 composed of small molecules as an absorbent material.

[0099] In one embodiment, a conductive contact between the upper electrode 7 of cell 3 and at least one busbar 11 via at least one via point 17 may be generated as follows: A) Localized laser ablation or targeted mechanical damage to the insulating layer between the upper electrode 7 and the busbar 11, followed by conductive connection with conductive PSA or conductive adhesive, such as UV-curable or thermosetting epoxy or acrylic adhesive. B) Deposition of a structured insulating layer by printing or coating, preferably in combination with a lithography step, such that the insulating layer is interrupted at desired locations, followed by conductive bonding with conductive PSA or conductive adhesive, such as UV-effective or thermosetting epoxy or acrylic adhesive. C) Deposition of a topographically advanced conductive structure onto the upper electrode 7 of cell 3, for example, by roughening the upper electrode 7 using a conductive adhesive or, for example, a laser, and subsequent deposition of a thin insulating layer that insulates the cell from the busbar at all locations away from the topographically complex region.

[0100] In another exemplary embodiment, for the purpose of contact according to A), the insulating layer 21, preferably formed from SiOCH, is locally removed by scraping or laser treatment of the layer 21, and then electrically connected by subsequent application of droplets of a conductive adhesive, such as a silver-containing adhesive.

[0101] Figure 3 is a plan view schematic of one exemplary embodiment of a photovoltaic element 1, which includes a plurality of series-connected cells 3 having conductive contacts 13 including via points 17 located at a distance A from each other. The same and functionally identical elements are denoted by the same reference numerals; therefore, please refer to the above description for details.

[0102] Cell 3 for 1 to n-1 has a width B(B n ) is smaller in width B (B1~B n-1 ) has. The length L of cell 3 is formed identically in each case. The length L of cell 3 is greater than the width B of cell 3. The photovoltaic element 1 in this exemplary embodiment is a photovoltaic element 1 using thin-film technology.

[0103] The areas of 2 to n-1 cells 3 interconnected in series in the lateral direction Q are the same, and the area of ​​the nth cell 3 is larger than that of the other cells 3. Each busbar 11 is located on the first cell 3 and on the nth cell 3. The busbar 11 on the nth cell 3 has three via points 17, which are formed at a distance A from each other in the longitudinal direction of the busbar 11, thereby forming conductive contact 13 with the upper electrode 7 of the nth cell 3. Regions with less photocurrent generation are located in the surrounding area 19 around the via points 17 in each case.

[0104] In this exemplary embodiment, the first cell 3, given a width B smaller than the widths of cells 3 from 2 to n-1 and n, is inert or at least nearly inert, in particular by being covered or deactivated by busbars.

[0105] Figure 4 is a plan view schematic of one exemplary embodiment of a photovoltaic element 1, which includes conductive contacts 13 including via points 17 located at a distance A from each other. The same and functionally identical elements are denoted by the same reference numerals; therefore, please refer to the above description for further details.

[0106] Cell 3 for 1 to n-1 has a width B(B n ) is smaller in width B (B1~B n-1 ) has, and cell 3 has a width B (B2 to B) of 2 to n-1 cells. n-1 It has a smaller width B(B1) compared to ). The length L of cell 3 is formed identically in each case.

[0107] Each busbar 11 is positioned on the first cell 3 and on the nth cell 3. The busbar 11 on the nth cell 3 has three via points 17, which are formed at a distance A from each other in the longitudinal direction of the busbar 11, thereby forming conductive contact 13 with the upper electrode 7 of the nth cell 3. Regions with less photocurrent generation exist in the surrounding area 19 around the via points 17 in each case.

[0108] The surrounding region 19 around via point 17 is shown to show a decrease in photocurrent generation before degradation in surrounding region 19A around via point 17, and a decrease in photocurrent generation after degradation in surrounding region 19B around via point 17.

[0109] In this exemplary embodiment, the first cell 3, given a width B smaller than the widths of cells 3 2 to n-1 and n, is inert or at least nearly inert, in particular by being covered or deactivated by the busbar 11.

[0110] Figure 5 is a plan view schematic of one exemplary embodiment of a photovoltaic element 1, which includes a plurality of series-connected cells 3 having conductive contacts 13 including via points 17 located at a distance A from each other. The same and functionally identical elements are denoted by the same reference numerals; therefore, please refer to the above description for details.

[0111] Cell 3 for 1 to n-1 has a width B(B n ) is smaller in width B (B1~B n-1 ) has a cell width B(B1~B n-1 ) are the same. The length L of cell 3 is formed identically in each case. The length L of cell 3 is greater than the width B of cell 3, where. The photovoltaic element 1 of this exemplary embodiment is a photovoltaic element 1 using thin-film technology.

[0112] Each structuring line 21 is formed in a closed manner around the via point 17 together with the surrounding area 19 around the via point 17, isolating the lower contact 5 or upper contact 7 within the surrounding area 19 around the via point from the rest of the area of ​​cell 3, thereby electrically insulating the lower contact 5 or upper contact 7 from the rest of the area of ​​cell 3.

[0113] In this exemplary embodiment, the first cell 3, given a width B smaller than the widths of cells 3 2 to n-1 and n, is inert or at least nearly inert, in particular by being covered or deactivated by the busbar 11.

Claims

1. A photovoltaic element (1) comprising a substrate (27) and n cells (3) arranged on the substrate (27) from a first cell (3) to an nth cell (3), wherein each cell (3) has a lower electrode (5), an upper electrode (7), and a layer system (9) including at least one photoactive layer (10), the layer system (9) being positioned between the lower electrode (5) and the upper electrode (7), and the cells (3) being interconnected in series with each other, and the photovoltaic element (1) having at least one busbar (11) connected to the first cell (3) and / or the nth cell (3) by conductive contact (13), wherein the at least one busbar -(11), the conductive contact (13) between the upper electrode (7) of the first cell (3) and / or the upper electrode (7) of the nth cell (3) is formed in each case by via points (17) located at a specific distance A (15) from each other in the longitudinal direction of the busbar (11), in the region between each of the via points (17), in which no conductive contact (13) is formed between the upper electrode (7) and the at least one busbar (11), and the surrounding region (19) around the via points (17) in a surrounding circle having a diameter of less than A / 2 is not photoactive or has a reduced degree of photoactivity compared to at least the region outside the surrounding region (19) around the via points (17), Each of the n cells (3) has a specific width B and a specific length L in each case, the first cell (3) and / or the nth cell (3) has a larger width B than the 2 to n-1 cells (3), and the n cells (3) each have the same length L, and the n cells (3) from the first cell (3) to the nth cell (3) are arranged relative to each other along their longitudinal sides, and the areas of the 2 to n-1 cells (3) are the same size as each other, thereby the photocurrent generation of the first cell (3) and / or the nth cell (3) when uniformly illuminated from a surface of the photovoltaic element (1) facing away from the at least one busbar (11) is the same as or greater than that of the 2 to n-1 cells (3).

2. The photovoltaic element (1) according to claim 1, characterized in that the photocurrent generation of the first cell (3) and / or the nth cell (3) is at least 10% greater than that of the 2 to n-1 cells (3) when uniformly illuminated from a surface of the photovoltaic element (1) facing away from the at least one busbar (11).

3. The photovoltaic element (1) according to claim 1 or 2, characterized in that a protective layer (21) having a mechanical protective function, an oxygen barrier function and / or a moisture barrier function is disposed between the at least one busbar (11) and the upper electrode (7) and / or the layer system (9) of the first cell (3) and / or the nth cell (3), wherein the protective layer (21) is at least partially perforated in the surrounding area (19) around the via point (17).

4. The photovoltaic element (1) according to any one of claims 1 to 3, characterized in that the via points (17) are formed at a distance (15) from each other in the longitudinal direction of the busbar (11).

5. The photovoltaic element (1) according to any one of claims 1 to 4, characterized in that the width B of cells (3) 2 to n-1 is 0.5 cm to 5 cm and / or the length L of cells (3) 1 to n is 10 cm to 20 m, and / or the width B of the first cell (3) and / or the nth cell (3) is increased by at least 5% compared to the cells (3) 2 to n-1, thereby the photocurrent generation of the first cell (3) and / or the nth cell (3) when uniformly illuminated from the surface of the photovoltaic element (1) facing away from the at least one busbar (11) is greater compared to the cells (3) 2 to n-1.

6. The photovoltaic element (1) according to any one of claims 1 to 5, characterized in that either the lower electrode (5) or the upper electrode (7) in the surrounding area (19) around the via point (17) is electrically insulated from the lower electrode (5) or the upper electrode (7) of the first cell (3) and / or the nth cell (3) respectively by a closed circular or rectangular structuring line (23), in each case, so that the shunt current path between the lower electrode (5) and the upper electrode (7) in the surrounding area (19) around the via point (17) does not result in a short circuit of the corresponding first cell (3) and / or nth cell (3).

7. The photovoltaic element (1) according to any one of claims 1 to 6, characterized in that the surrounding area (19) around the via point (17) does not have a layer system (9) including a photoactive layer (10) in each case.

8. In each case, the layer system (9) of the cell (3) in the region around the via point (17) within the surrounding area (19) around the via point (17) is further characterized in that at the via point (17), it has a separation line (25) that at least partially prevents the diffusion of moisture that has penetrated into the layer system (9) outside the surrounding area (19) around the via point (17), as described in any one of claims 1 to 7.

9. A photovoltaic element (1) according to any one of claims 1 to 8, characterized in that it is a photovoltaic thin film element and / or a flexible photovoltaic thin film element.

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