DE102023106179B4 - Method for arranging an electrically conductive contacting structure on a solar cell and a printing unit for forming a plurality of electrically conductive contacting elements - Google Patents

Abstract

Method for arranging an electrically conductive contacting structure (5) on a solar cell (1) which has at least a plurality of mutually spaced, electrically conductive contacting elements of a first polarity (2),
wherein an electrically conductive connecting element (3) is arranged between the electrically conductive contacting structure (5) and the contacting elements of the first polarity (2) of the solar cell (1) in each case to form an electrically conductive connection between the contacting element (2) and the contacting structure (5), and a plurality of electrically non-conductive adhesive elements (4) are arranged between the surface of the solar cell (1) and the contacting structure (5), which adhesive elements are integrally connected to the solar cell (1) and the contacting structure (5),
wherein the connecting elements (3) are applied to the solar cell (1) and/or to the contacting elements (2) by dispensing a contacting pressure medium and the adhesive elements (4) are applied to the solar cell (1) and/or to the contacting elements (2) by dispensing an adhesive medium from one or more dispensing openings (7d)
and wherein by switching a multi-way valve (7) which has at least two inlets (7a, 7b) and a pressure medium outlet (7c) fluidically connected to the outlet openings (7d), a first pressure medium supplied via the first inlet (7a) or a second pressure medium supplied via the second inlet (7b) is selectively dispensed from the outlet openings (7d).

Description

The invention relates to a method for arranging an electrically conductive contacting structure on a solar cell and a printing unit therefor.

When connecting a solar cell in a solar cell module, an electrically conductive contact structure is typically arranged on the solar cell.

It is known to use an electrically conductive cell connector, typically in the form of a metallic cell connector, particularly a metal strip, as a contacting structure. Such cell connectors are typically used to connect adjacent solar cells in series.

It is also known to use another solar cell as a contacting structure to form a shingling arrangement, wherein a solar cell is partially covered by a neighboring solar cell serving as a contacting structure and is electrically connected to it.

For creating an electrically conductive connection between the contact structure and the solar cell, connections using soldering and conductive adhesive are known. However, a connection using soldering has disadvantages, as the heat applied to the solar cell during the soldering process limits the materials used for the solar cell. The use of conductive adhesive is cost-intensive due to the high material costs of the conductive adhesive.

From the Scripture US 2019/0074395 A1 A solar cell module with a plurality of solar cells is known, in which each solar cell has a semiconductor substrate, first electrodes are located on the front side of the semiconductor substrate, second electrodes are located on the back side of the semiconductor substrate, and a plurality of connecting elements electrically connect the first electrodes of a first solar cell to a second electrode of a second, adjacent solar cell. Non-conductive adhesive elements are also provided. Both the electrically conductive connecting elements and the non-conductive adhesive elements can be arranged on the substrate by dispensing.

EP 1 852 917 A2 teaches a bifacial photovoltaic device comprising a bifacial solar cell with a semiconductor layer, the semiconductor layer having a first and a second side surface, the first surface having a first passive layer and the second surface having a second passive layer. Metallic structures serving as electrical contacts are located on the surfaces.

Furthermore, DE 10 2010 024 331 A1 A method for bonding a ribbon-shaped conductor to a solar cell is known. Both conductive adhesive and non-conductive structural adhesive can be applied discontinuously using a piezo-jet dispenser, allowing interaction between the two adhesives to be specifically prevented or induced.

The present invention is therefore based on the object of providing a method for arranging an electrically conductive contact structure on a solar cell, which enables a cost-effective and mechanically stable connection between the solar cell and the contact structure. Furthermore, a printing unit for carrying out such a method is to be provided.

This object is achieved by a method for arranging an electrically conductive contacting structure on a solar cell according to claim 1 and a printing unit for forming a plurality of electrically conductive contacting elements according to claim 10. Advantageous embodiments can be found in the dependent claims.

The printing unit according to the invention is preferably designed to carry out the method according to the invention, in particular an advantageous embodiment thereof. The method according to the invention is preferably designed to be carried out using the printing unit according to the invention.

The invention is based on the finding that cost savings are possible if the solar cell to be connected does not necessarily have to have a continuously metallized contact surface for connection to the contacting structure, but rather the solar cell can have at least a plurality of spaced-apart, electrically conductive contacting elements of a first polarity. To form the electrical contact, the contacting elements of the first polarity are electrically conductively connected to the contacting structure by means of conductive connecting elements. To form a stable mechanical connection, a plurality of electrically non-conductive adhesive elements are arranged between the solar cell and the contacting structure and are integrally connected to the solar cell and the contacting structure.

This allows material to be used when forming the metallic contact surfaces on of the solar cell can be saved, and in addition, a stable mechanical connection can be formed using materials that are more cost-effective than, for example, conductive adhesives to form an electrically non-conductive, material-locking connection.

The method according to the invention thus serves to arrange an electrically conductive contacting structure in a solar cell, which has at least a plurality of spaced-apart, electrically conductive contacting elements of a first polarity, wherein an electrically conductive connecting element is arranged between the contacting structure and the contacting elements of the first polarity of the solar cell in order to form an electrically conductive connection between the contacting element and the contacting structure. Furthermore, a plurality of electrically non-conductive adhesive elements are arranged between the surface of the solar cell and the contacting structure and are integrally connected to the solar cell and contacting structure. The contacting elements are applied to the solar cell and/or the connecting element by dispensing a contacting pressure medium, and the adhesive elements are applied to the solar cell and/or the connecting element by dispensing an adhesive medium from one or more pressure openings. The pressure openings are fluidically connected to at least one outlet of a multi-way valve, which has at least two inlets and one outlet. The pressure media are fed to the multi-way valve so that by switching the multi-way valve, either a first pressure medium fed via the first inlet of the multi-way valve or a second pressure medium fed via the second inlet of the multi-way valve is output from the pressure openings.

This achieves the aforementioned advantages. Furthermore, by using a contact printing medium and an adhesive medium applied by dispensing, cost-effective printing processes can be used on an industrial scale in inline processes.

Dispensing refers to the dispensing of a specific amount of a dispensing medium, typically a liquid, pasty, powdered, or fine-grained medium, using a dispenser. Accordingly, the term dispenser refers to a device or container that dispenses a specific amount of its contents, the dispensing medium.

In the present case, the dispensing media, adhesive medium and contact pressure medium, are preferably designed as pasty media.

Advantageously, at least one, preferably exactly one, adhesive element is arranged between two contacting elements. In particular, it is advantageous for the connecting elements and the adhesive elements to be arranged alternately in a line, preferably along a straight line.

This results in an advantageous division for forming a large-area metallic contact to achieve a low electrical resistance between the solar cell and the contacting element and, on the other hand, a stable mechanical connection due to the intermediate adhesive elements.

In order to ensure permanent electrical contact and to increase mechanical stability, it is advantageous that the connecting elements are each integrally connected to the contacting elements and the contacting structure.

It is therefore advantageous to use an electrically conductive adhesive (ECA electrically conductive adhesive, especially conductive varnish) to form the connecting elements.

It is within the scope of the invention to use a conductive adhesive as the electrically conductive adhesive, in particular a conductive adhesive consisting of the adhesive (resin) and inorganic, electrically conductive fillers. The volume fraction of the fillers is preferably approximately 30 volume percent. Advantageously, fillers from the group consisting of silver, gold, palladium, nickel, and platinum are used. It is within the scope of the invention to use a filler from the group consisting of copper, aluminum, tin, lead, silicon, and bronze.

It is also within the scope of the invention to use a conductive ink based on silver (silver conductive ink or conductive silver), copper (copper conductive ink), or graphite particles (graphite conductive ink) as the electrically conductive adhesive. The conductive ink advantageously contains a binder, in particular a one-component solvent-based ink or a synthetic resin (one- or two-component).

It is also within the scope of the invention to use one or more of the materials used in the construction of the connecting elements US10287442B2 and in particular those listed there in Table 1 (table 1, column 14).

To form the adhesive elements, known, non-conductive adhesives can be used In particular, the adhesive used is preferably a non-metallic substance that is capable of bonding materials through surface adhesion and its internal strength (cohesion). Preference is given to using an electrically non-conductive, physically bonding adhesive, in particular a solvent-based adhesive, in particular a solvent-based wet adhesive. The use of an adhesive from one of the groups contact adhesives, dispersion adhesives, hot melt adhesives or plastisols is also within the scope of the invention. Furthermore, it is within the scope of the invention to use an electrically non-conductive, chemically curing adhesive, in particular from one of the groups polyaddition adhesives, polycondensation adhesives or polymerization adhesives.

It is within the scope of the invention to arrange the connecting elements and the adhesive elements on one of the solar cell or contact structure elements and then to bring the other of these elements closer to the solar cell or contact structure and bring it into contact with the connecting elements and adhesive elements. It is also within the scope of the invention to arrange subgroups of the contact elements and/or the adhesive elements on the solar cell and the remaining subgroups on the contact structure and then to bring the solar cell and contact structure closer together in order to form contact between each connecting element and each adhesive element with both the solar cell and the contact structure.

It is already known to move solar cells in an inline process and to print them with printing materials. Therefore, it is advantageous to arrange both the connecting elements and the adhesive elements on the solar cell and then bring the contact structure closer to the solar cell to form contact with the connecting elements and the adhesive elements.

In order to reduce the required process time, it is advantageous that the connecting elements are applied simultaneously to one of the solar cell or contacting element elements, preferably to the contacting elements, and that the adhesive elements are applied simultaneously to one of the solar cell or contacting element elements, preferably to the solar cell.

In a further advantageous embodiment, at least a portion of the adhesive elements and a portion of the connecting elements are applied from a nozzle to one of the solar cell or contacting element, preferably to the contacting elements. The adhesive medium is dispensed from the nozzle for applying the adhesive elements, and the connecting medium is dispensed from the nozzle for applying the connecting elements. This provides the advantage that only one nozzle can be used for both applying the adhesive medium and the connecting medium.

The method according to the invention is suitable for contacting solar cells that have only metallic contact structures of one polarity on one side. In particular, it is advantageous to use known elongated, particularly rectilinear, electrically conductive metallic contact elements of a solar cell, so-called contact fingers, as the plurality of spaced-apart, electrically conductive contact elements of the first polarity.

In an advantageous embodiment of the method, the electrically conductive connecting elements are therefore arranged on the contact fingers of the solar cell in order to form an electrically conductive connection with the contact fingers. In particular, it is advantageous that at least one, preferably exactly one, electrically conductive connecting element is arranged on each contact finger of the solar cell.

In an advantageous further development, at least one, preferably exactly one, adhesive element is arranged between the contacting fingers of the solar cell.

The method according to the invention is also suitable for use with solar cells that have, on one side of the solar cell, in addition to the plurality of spaced-apart, electrically conductive contact elements of a first polarity, a plurality of spaced-apart, electrically conductive contact elements of a second polarity. Such solar cells can, for example, be designed as single-sided contactable solar cells, with the contact elements of the first and second polarities typically being arranged on the rear side of the solar cell.

In an advantageous embodiment, the solar cell therefore has a plurality of mutually spaced, electrically conductive contacting elements of a second polarity opposite to the first polarity, wherein the contacting elements of the first and second polarities are arranged alternately. Furthermore, the electrically non-conductive adhesive elements are arranged between the contacting elements of the second polarity and the contacting structure. In this advantageous embodiment, the contacting structure thus covers both the contacting elements of the first and second polarities. rity, however, only an electrically conductive connection with the contacting elements of the first polarity is to be formed. It is therefore advantageous to arrange electrically non-conductive adhesive elements on the contacting elements of the second polarity. This achieves electrical insulation between the contacting elements of the second polarity and the contacting structure, and furthermore, a stable mechanical connection between the contacting structure and the solar cell is formed.

For electrically contacting the contacting elements of the second polarity, it is advantageous that a second electrically conductive contacting structure is arranged on the solar cell, wherein electrically non-conductive adhesive elements are arranged between the contacting elements of the first polarity of the solar cell and the second contacting structure, which adhesive elements are integrally connected to the solar cell and the contacting structure, and electrically conductive contacting elements are arranged between the contacting elements of the second polarity of the solar cell and the second contacting structure. As with the first contacting structure, the connecting elements are applied to the solar cell and/or the contacting element by dispensing a contacting pressure medium, and the adhesive elements are applied by dispensing an adhesive medium from one or more pressure openings. As stated at the outset, it is within the scope of the invention for the solar cell to be connected to an adjacent solar cell by means of a cell connector. In an advantageous embodiment, the electrically conductive contacting structure is therefore designed as a cell connector, in particular a metallic cell connector, preferably a metal strip or metal wire, particularly preferably made of copper. It is also within the scope of the invention to form the electrically conductive contact structure as a metal foil, a metal-coated foil or as a carrier material equipped with conductor tracks.

As stated above, it is also within the scope of the invention to form a shingle arrangement of solar cells. In an advantageous embodiment, the electrically conductive contact structure is a second solar cell with one or more electrical contact elements, and the connecting elements are electrically conductively connected to the contact structure of the second solar cell, in particular to the contact element of the solar cell.

An example of a print head for forming a plurality of electrically conductive contacting elements and a plurality of electrically non-conductive adhesive elements is described below.

The print head has a first group of output openings which are fluidically connected to a first print medium inlet and the print head has a second group of output openings which are fluidically connected to a second print medium inlet, so that a first print medium can be supplied exclusively to the first group of output openings by means of the first print medium inlet and a second print medium can be supplied exclusively to the second group of output openings by means of the second print medium inlet.

The print head thus enables a time-saving formation of the connecting elements and the adhesive elements according to the method according to the invention by means of dispensing since the connecting elements can be formed by means of the first group of dispensing openings and the adhesive elements can be formed by means of the second group of dispensing openings or vice versa.

In particular, it is advantageous that the connecting elements and the adhesive elements are formed simultaneously with the print head.

In an advantageous embodiment, the output openings of the first group and the second group are arranged alternately along a line, in particular a straight line, on an output side of the print head. This provides the advantage that the alternating, particularly preferably simultaneous, formation of the connecting elements and adhesive elements is possible in a simple manner.

Advantageously, the first group of dispensing openings has one, preferably exactly one, dispensing opening for each connecting element to be formed on the solar cell, and the second group of dispensing openings has one, preferably exactly one, dispensing opening for each adhesive element to be formed on the solar cell. This allows all connecting elements and adhesive elements to be formed on the solar cell simultaneously in a single printing process.

The aforementioned object is further achieved by a printing unit for forming a plurality of electrically conductive contacting elements and a plurality of electrically non-conductive adhesive elements. The printing unit according to the invention comprises a print head and a multi-way valve with at least two inlets and one outlet, wherein the print head has at least one discharge opening that is fluidly connected to the outlet of the multi-way valve. so that by switching the multi-way valve, either a first pressure medium supplied via the first inlet of the multi-way valve or a second pressure medium supplied via the second inlet of the multi-way valve can be dispensed from the dispensing openings.

The printing unit has the advantage that both connecting elements and adhesive elements can be formed by means of a dispensing opening of the print head, in that the contacting printing medium is supplied via one of the two inlets of the multi-way valve and the adhesive medium is supplied via the other inlet.

In an advantageous use of the printing unit, the output opening of the print head is moved along a line, preferably along a straight line over the solar cell or the contacting structure, preferably over the solar cell, and contacting printing medium and adhesive medium are alternately output from the output opening, so that an alternating arrangement of contacting elements and adhesive elements is achieved.

As described at the outset, it is particularly advantageous to use the print head described by way of example, in particular an advantageous embodiment thereof, to carry out the method according to the invention.

It is also advantageous to use the printing unit according to the invention, in particular an advantageous embodiment thereof, to carry out the method according to the invention.

• 1 eine Anordnung von einer Solarzelle und Kontaktierungsstrukturen, die mit einer ersten Ausgestaltung eines erfindungsgemäßen Verfahrens ausgebildet wurden, in Draufsicht von oben sowie in Schnittdarstellung;
• 2 ein erstes Ausführungsbeispiel einer erfindungsgemäßen Druckeinheit zur Durchführung des Verfahrens gemäß dem ersten Ausführungsbeispiel;
• 3 eine Anordnung von Solarzelle und Kontaktierungsstrukturen, welche mit einem zweiten Ausführungsbeispiel eines erfindungsgemäßen Verfahrens ausgebildet wurden, in Draufsicht von oben und in Schnittdarstellung;
• 4 ein Ausführungsbeispiel eines Druckkopfes zur Durchführung des Verfahrens gemäß dem zweiten Ausführungsbeispiel;
• 5 einer Anordnung von Solarzelle und Kontaktierungsstruktur, welche mit einem dritten Ausführungsbeispiel eines erfindungsgemäßen Verfahrens ausgebildet wurden, in Draufsicht von oben und in Schnittansicht und
• 6 ein Ausführungsbeispiel eines Druckkopfes zur Durchführung des Verfahrens gemäß dem dritten Ausführungsbeispiel.

Further advantageous features and embodiments are explained below with reference to figures and exemplary embodiments. Shown are:

• 1 an arrangement of a solar cell and contacting structures formed using a first embodiment of a method according to the invention, in a plan view from above and in a sectional view;
• 2 a first embodiment of a printing unit according to the invention for carrying out the method according to the first embodiment;
• 3 an arrangement of solar cell and contact structures, which were formed using a second embodiment of a method according to the invention, in a plan view from above and in a sectional view;
• 4 an embodiment of a print head for carrying out the method according to the second embodiment;
• 5 an arrangement of solar cell and contact structure, which were formed with a third embodiment of a method according to the invention, in plan view from above and in sectional view and
• 6 an embodiment of a print head for carrying out the method according to the third embodiment.

All figures are schematic representations and not to scale. For clarity, the actual number of elements in some figures has been reduced. This particularly applies to the number of contact fingers of a solar cell and, accordingly, the number of print nozzles of a print head, contact elements, and connecting elements.

The same reference symbols in the figures denote the same or identically acting elements.

• Eine Solarzelle 1 weist eine Mehrzahl zueinander beabstandeter, elektrisch leitender Kontaktierungselemente 2 auf, welche als an sich bekannte, geradlinige, metallische Kontaktierung Finger ausgebildet sind. Die Kontaktierungsfinger sind parallel und beabstandet zueinander angeordnet. In der vereinfachten Darstellung in 1 sind lediglich vier Kontaktierungselemente 2 gezeigt.

In 1 an arrangement of solar cells and contact structures is shown, which were formed using a first embodiment of the method according to the invention:

• A solar cell 1 has a plurality of spaced-apart, electrically conductive contact elements 2, which are designed as known, straight, metallic contact fingers. The contact fingers are arranged parallel and spaced from one another. In the simplified illustration in 1 only four contacting elements 2 are shown.

Electrically conductive connecting elements 3 are arranged on each contacting element 2. An electrically non-conductive adhesive element 4 is arranged between each connecting element 3.

Contacting structures 5 are arranged on the sides of the connecting elements 3 and adhesive elements 4 opposite the solar cell.

The contact structures 5 are formed as metal strips made of copper and serve as cell connectors to electrically connect the solar cell 1 in series with a neighboring solar cell. For this purpose, the cell connectors have a greater length than shown in the drawing for reasons of clarity. 1 shown.

The contacting elements 2 are made of electrically conductive adhesive (ECA). The adhesive elements are made of electrically non-conductive adhesive.

In the present case, a mechanical connection is formed between the contacting structures 5 and the solar cell 1, wherein both the connecting elements 3 and the adhesive elements 4 are integrally connected to the solar cell and a contacting structure.

As in 1a) As can be seen, three linear contacting structures 5 are arranged parallel and spaced apart from one another and perpendicular to the contacting elements 2.

1b) shows a section along section line A in 1a) , where the cutting plane is perpendicular to the drawing plane in 1a) stands.

As in 1b) As can be seen, connecting elements 3 and adhesive elements 4 are directly adjacent to each other.

In 2 is an embodiment of a printing unit according to the invention for carrying out the 1 described procedure.

The printing unit is designed to form a plurality of electrically conductive connecting elements 3 and a plurality of electrically non-conductive adhesive elements 4. The printing unit has a print head 6 and a multi-way valve 7 with a first pressure medium inlet 7a and a second pressure medium inlet 7b and a pressure medium outlet 7c. The multi-way valve 7 is arranged on the print head 6.

In this embodiment, the print head has three output openings 7d, each of which is fluidly connected to the print medium outlet 7c of the multi-way valve 7 via print medium lines of the print head 6.

The multi-way valve 7 is designed such that by switching the multi-way valve, pressure medium can be supplied either via the first pressure medium inlet 7a to the output openings 7d or via the second pressure medium inlet 7b to the output openings 7d.

To carry out the 1 In the method described, the print head is moved perpendicular to the contacting elements 2 over the solar cell. Adhesive medium (electrically non-conductive adhesive) is supplied via the first print medium inlet 7a, and the contacting print medium (ECA) is supplied via the second print medium inlet 7b. By means of the multi-way valve 7, the output of print medium at the output openings 7d is controlled in such a way that during the movement of the print head 6 perpendicular to the contacting elements 2, ie in 1 for example, from bottom to top the three in 1a) shown lines, each line having alternating adhesive elements 4 and connecting elements 3, so that exactly one connecting element 3 is arranged between each two adhesive elements 4.

Subsequently, the three contacting structures 5 are brought into contact with the adhesive elements 4 and the connecting elements 3 in order to form the material-to-material connection and the electrically conductive connection between the contacting structure 5 and the contacting elements 2 of the solar cell by means of the connecting elements 3 and to form the material-to-material, electrically non-conductive connection between the surface of the solar cell 1 between the contacting elements 2 and the contacting structures 5.

• Die in 3a) in Draufsicht von oben gezeigte Solarzelle 1 ist als einseitig kontaktierbare Solarzelle ausgebildet und weist zusätzlich zu den Kontaktierungselementen 2 der ersten Polarität Kontaktierungselemente 2a einer zweiten Polarität auf. Die zweite Polarität ist der ersten Polarität entgegengesetzt. Vorliegend stellen die Kontaktierungselemente der ersten Polarität positive elektrische Kontakte und die Kontaktaufnahme der zweiten Polarität negative elektrische Kontakte dar.

In 3 An arrangement of solar cells and contact structures is shown, which were formed by means of a second embodiment of the method according to the invention. The method has significant similarities with the 1 described procedures, therefore, to avoid repetition, only the essential differences are discussed:

• The 3a) The solar cell 1 shown in a top view is designed as a solar cell with contact on one side and, in addition to the contact elements 2 of the first polarity, has contact elements 2a of a second polarity. The second polarity is opposite to the first polarity. In this case, the contact elements of the first polarity represent positive electrical contacts, and the contact elements of the second polarity represent negative electrical contacts.

The contacting elements of the first polarity and the second polarity are arranged alternately and parallel to each other and spaced apart from each other.

In this embodiment, the solar cell 1 is also electrically contacted by contacting structures 5, which are designed as metal strips made of copper and thus as cell connectors known per se.

In contrast to the 1 The arrangement shown in 3 shown arrangement, the contacting elements 2 of the first polarity are electrically contacted exclusively by the two contacting structures 5' and the contacting elements 2a of the second polarity are electrically contacted exclusively by the two contacting structures 5.

Adhesive elements 4 and connecting elements 3 are arranged alternately and spaced apart from one another along the contact structures 5, 5'.

As in 3a) As can be seen, the arrangement is such that an electrically conductive connecting element 3 is arranged between each of the two contacting structures 5' and the contacting elements 2 of the first polarity, and an adhesive element 4 is arranged between each of the two contacting structures 5' and the contacting elements 2a of the second polarity. Accordingly, the two contacting structures 5' are only electrically conductively connected to the contacting elements 2 of the first polarity.

In the reverse arrangement, an electrically non-conductive adhesive element 4 is arranged between the two contacting structures 5 and the contacting elements 2 of the first polarity, and an electrically conductive connecting element 3 is arranged between the two contacting structures 5 and the contacting elements 2a of the second polarity. Accordingly, the two contacting structures 5 are only electrically conductively connected to the contacting elements 2a of the second polarity.

The connecting elements 3 and the adhesive elements 4 are arranged at a distance from one another. However, since both the adhesive elements 4 and the connecting elements 3 are integrally connected to the solar cell and to a contact structure, sufficient mechanical stability is ensured. 3b) is analogous to 1 a section along the section line A in 3a) and shown perpendicular to the drawing plane.

The training of the 3 The arrangement shown can be adjusted using the 4 illustrated first embodiment of a print head for forming a plurality of electrically conductive contacting elements and a plurality of electrically non-conductive adhesive elements.

The print head 8 has a first print medium inlet 8a and a second print medium inlet 8b. Furthermore, the print head has a plurality of first output openings 8c and a plurality of second output openings 8d, wherein the first and second output openings are arranged alternately along a straight line.

The first output openings 8c are fluidically connected to the first print medium inlet 8a via lines (schematically shown as dashed lines) of the print head, and the second output openings 8d are fluidically connected to the second print medium inlet 8b via lines (schematically shown as solid lines) of the print head 8.

This makes it possible to supply two different print media, in particular to supply and dispense them simultaneously. In this case, the adhesive medium is supplied via the first print medium inlet 8a, and the contact print medium is supplied via the second print medium inlet 8b. Accordingly, adhesive medium is dispensed at the first dispensing openings, and contact print medium is dispensed at the second dispensing openings.

This allows four elements to be simultaneously used for the 3 shown arrangement, two connecting elements 3 and two adhesive elements 4, wherein the connecting elements 3 on the one hand and the adhesive elements 4 on the other hand are each arranged on a diagonal of a rectangle and at the corner points of this rectangle.

By moving the print head, four elements (two connecting elements and two adhesive elements) can be formed successively, so that for the 3 shown arrangement eight printing operations are necessary.

In a variation of the 4 The first example of a print head shown in FIG. 1 has, according to a further development, for each of the 3 shown connecting element 3 has a first output opening 8c fluidly connected to the first pressure medium inlet 8a and for each of the 3 The adhesive element 4 shown in the arrangement has a second output opening 8d which is fluidically connected to the second pressure medium inlet 8b, so that by means of a printing process all connecting elements 3 and adhesive elements 4 are simultaneously pressed onto the 3 shown positions can be formed.

In 5 a solar cell with a partial region of an electrically conductive contact structure is shown, which was formed by means of a third embodiment of the method according to the invention.

The solar cell 1 has, as in the 1 described embodiment comprises a plurality of linear contacting elements 2 of a first polarity arranged parallel to one another, which are designed as metallic contacting fingers and arranged at a distance from one another.

In contrast to the 1 The procedure described in 5 In the arrangement shown, a further solar cell 1a is used as an electrically conductive contact structure. The contact structure 5 is thus identical to the Solar cell 1 is formed and overlaps the solar cell 1 at the right edge, wherein the contact structure 5 in the plan view from above according to 5a) is arranged above the solar cell 1, so that a front side of the solar cell 1 is arranged on a back side of the contacting structure 5.

The contact structure 5 designed as a solar cell is only indicated by dotted lines in the overlapping partial area.

Connecting elements 3 and adhesive elements 4 are arranged alternately along a contact line A, which extends perpendicular to the contact elements 2, wherein the connecting elements 3 are each arranged on a contact element 2 of the solar cell 1. In the present case, connecting elements 3 and adhesive elements 4 are spaced apart from one another.

In 5b) is a sectional view along the contact line A in 5a) shown, whereby here too the sectional plane is perpendicular to the drawing plane 5a). The solar cell 1 and the contact structure 5, designed as an identical solar cell 1a, have a full-surface metallization on the rear side, which thus represents a contact element 2a of the second polarity.

As in 5b) As can be seen, each contacting element 2 of the first polarity of the solar cell 1 is connected in a materially bonded and electrically conductive manner to the metallic rear side of the contacting structure 5 designed as a solar cell 1a by means of a connecting element 3. Furthermore, exactly one adhesive element 4 is arranged between each two connecting elements 3, which connects the solar cell 1 and the contacting structure 5 in a materially bonded but not electrically conductive manner.

The training of the 5 The arrangement shown is carried out by means of the 6 illustrated second embodiment of a print head for forming a plurality of electrically conductive contacting elements and a plurality of electrically non-conductive adhesive elements.

The print head 8 has a first print medium inlet 8a and a second print medium inlet 8b. Furthermore, the print head has a plurality of first output openings and a plurality of second output openings, wherein the first and second output openings are arranged alternately along a straight line. For example, a first output opening is designated by reference numeral 8c and a second output opening by reference numeral 8d.

The first output openings 8c are fluidly connected to the first print medium inlet 8a via lines of the print head and the second output openings 8d are connected to the second print medium inlet 8b via lines of the print head 8.

This makes it possible to supply two different print media, in particular to supply and dispense them simultaneously. In this case, the adhesive medium is supplied via the first print medium inlet 8a, and the contact print medium is supplied via the second print medium inlet 8b. Accordingly, adhesive medium is dispensed at the first dispensing openings, and contact print medium is dispensed at the second dispensing openings.

This allows the 5 The arrangement of connecting elements 3 and adhesive elements 4 shown can be produced by simultaneously dispensing adhesive medium from the first dispensing openings 8c and contact printing medium from the second dispensing openings 8d.

Reference symbol

1, 1a

solar cell

2

Contacting element of the first polarity

2a

Contacting element of the second polarity

3

connecting element

4

Adhesive element

5.5'

Contact structure

6

print head

7

Multi-way valve

7a

first print medium input

7b

second pressure medium inlet

7c

Print medium output

7d

Dispensing openings

8

print head

8a

first print medium input

8b

second pressure medium inlet

8c

first dispensing openings

8d

second dispensing openings

Claims (10)

Method for arranging an electrically conductive contacting structure (5) on a solar cell (1), which has at least a plurality of mutually spaced, electrically conductive contacting elements of a first polarity (2), wherein an electrically conductive connecting element (3) is arranged between the electrically conductive contacting structure (5) and the contacting elements of the first polarity (2) of the solar cell (1) in each case to form an electrically conductive connection between the contacting element (2) and the contacting structure (5), and a plurality of electrically non-conductive adhesive elements (4) are arranged between the surface of the solar cell (1) and the contacting structure (5), which adhesive elements are integrally connected to the solar cell (1) and the contacting structure (5), wherein the connecting elements (3) are applied to the solar cell (1) and/or to the contacting elements (2) by dispensing a contacting pressure medium and the adhesive elements (4) are applied to the solar cell (1) and/or to the contacting elements (2) by dispensing an adhesive medium from one or more dispensing openings (7d), and wherein by switching a multi-way valve (7) which has at least two inlets (7a, 7b) and one connected to the dispensing openings (7d) fluid-conducting connected pressure medium outlet (7c), optionally a first pressure medium supplied via the first inlet (7a) or a second pressure medium supplied via the second inlet (7b) is dispensed from the dispensing openings (7d). Procedure according to Claim 1 , characterized in that at least one, preferably exactly one, adhesive element (4) is arranged between two contacting elements (2), in particular that the connecting elements (3) and the adhesive elements (4) are arranged alternately in a line, in particular preferably along a straight line. Method according to one of the preceding claims, characterized in that the connecting elements (3) are each connected in a material-locking manner to the contacting elements and the contacting structure. Method according to one of the preceding claims, characterized in that the connecting elements (3) are applied simultaneously to one of the elements solar cell (1) or contacting element (2), preferably to the solar cell (1), and that the adhesive elements (4) are applied simultaneously to one of the elements solar cell (1) or contacting structure, preferably to the solar cell (1), in particular that the connecting elements (3) and the adhesive elements (4) are applied simultaneously to one of the elements solar cell (1) or contacting element (2), preferably to the contacting elements (2). Method according to one of the Claims 1 until 3 , characterized in that at least a subset of the adhesive elements (4) and a subset of the connecting elements (3) are applied from a nozzle to one of the solar cell (1) or contacting element (2), preferably to the contacting elements (2), wherein the adhesive medium is dispensed from the nozzle for applying the adhesive elements (4) and the connecting medium is dispensed from the nozzle for applying the connecting elements (3). Method according to one of the preceding claims, characterized in that the solar cell (1) has a plurality of mutually spaced, electrically conductive contacting elements (2a) of a second polarity opposite to the first polarity, wherein the contacting elements of the first (2) and the second polarity (2a) are arranged alternately and that the electrically non-conductive adhesive elements (4) are arranged between the contacting elements of the second polarity (2a) and the contacting structure (5). Procedure according to Claim 6 , characterized in that a second electrically conductive contacting structure (5') is arranged on the solar cell (1), wherein electrically non-conductive adhesive elements (4) are arranged between the contacting elements of the first polarity (2) of the solar cell (1) and the second contacting structure (5'), which adhesive elements are connected to the solar cell (1) and the contacting structure in a material-to-material manner, and electrically conductive connecting elements (3) are arranged between the contacting elements of the second polarity (2a) of the solar cell (1) and the second contacting structure (5'), wherein the connecting elements (3) are applied to the solar cell (1) and/or to the contacting element (2) by means of dispensing a contacting pressure medium and the adhesive elements (4) are applied to the solar cell (1) and/or to the contacting element (2) by means of dispensing an adhesive medium from one or more pressure openings (7d, 8c, 8d). Method according to one of the preceding claims, characterized in that the electrically conductive contacting structure (5, 5') is a cell connector, in particular a metallic cell connector, preferably a metal strip or metal wire. Procedure according to one of the preceding Claims 1 until 7 , characterized in that the electrically conductive contacting structure is a second solar cell (1) with one or more electrically conductive contacting elements, and that the connecting elements (3) are electrically conductively connected to the contacting structure of the second solar cell (1), in particular the contacting element of the second solar cell (1). Printing unit for forming a plurality of electrically conductive connecting elements (3) and a plurality of electrically non-conductive adhesive elements (4), with a print head (6) and with a multi-way valve (7) with at least two inlets (7a, 7b) and one pressure medium outlet (7c), wherein the print head (6) has at least one output opening (7d) which is fluidically connected to the pressure medium outlet (7c) of the multi-way valve (7), so that by switching the multi-way valve (7) either a first pressure medium supplied via the first inlet (7a) or a second pressure medium supplied via the second inlet (7b) can be output from the output openings (7d).

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