WO2023083477A1

WO2023083477A1 - Method of processing a substrate used for the manufacture of a solar cell arrangement, solar cell, and an apparatus for processing a substrate used for the manufacture of a solar cell arrangement, apparatus for manufacturing a current transportation wire for a solar cell

Info

Publication number: WO2023083477A1
Application number: PCT/EP2021/081701
Authority: WO
Inventors: Enrico SOVERNIGO
Original assignee: Applied Materials Italia SRL
Current assignee: Applied Materials Italia SRL
Priority date: 2021-11-15
Filing date: 2021-11-15
Publication date: 2023-05-19
Anticipated expiration: 2024-05-15

Abstract

A method of processing a substrate (10) used for the manufacture of a solar cell arrangement (1400) is provided. The method includes providing a substrate (10) having a conductive pattern (20) formed on a first side (402) of the substrate. The method includes providing a current transportation wire (200) having a first height (310) at a bulk portion (210) of the current transportation wire and a second height (320) at an end portion (220) of the current transportation wire. The second height is smaller than the first height. The method includes attaching the current transportation wire to the first side of the substrate in a manner such that the conductive pattern is electrically connected to the current transportation wire. The method includes providing a screen (610) over the substrate, the screen having an opening or set of openings (1010). The method includes transferring a printing material from the screen to the substrate through the opening or set of openings to print a first feature (810) on the first side of the substrate next to the end portion of the current transportation wire.

Description

METHOD OF PROCESSING A SUBSTRATE USED FOR THE MANUFACTURE OF A SOLAR CELL ARRANGEMENT, SOLAR CELL, AND AN APPARATUS FOR PROCESSING A SUBSTRATE USED FOR THE MANUFACTURE OF A SOLAR CELL ARRANGEMENT, APPARATUS FOR MANUFACTURING A CURRENT TRANSPORTATION WIRE FOR A SOLAR CELL

FIELD

[0001] Embodiments described herein relate to methods and apparatuses for manufacturing solar cell arrangements including a plurality of partially overlapping solar cell pieces, or shingled solar cell arrangements.

BACKGROUND

[0002] Solar cells are photovoltaic devices that convert sunlight directly into electrical power. The efficiency of the solar cells can be affected by an active area on a front surface of the solar cell which is exposed to light for converting sunlight into electrical power. The active area can be reduced due to the presence of electrical contacts, such as fingers and/or bus bars, on the front surface of the solar cells. The presence of the electrical contacts on the front surface of the solar cells can thus reduce a module power of a solar cell module including the solar cells.

[0003] Shingled solar cell arrangements can increase an output power of a solar cell module. The increase in the output power can be affected by a quality of a manufacturing process, such as a quality of the elements used to assemble the shingled solar cell arrangement. Further, a proper assembling of the shingled solar cell arrangement can be cumbersome, and a throughput and/or yield can be low.

[0004] In view of the above, new methods and apparatuses for processing solar cells for the manufacture of shingled solar cell arrangements that overcome at least some of the problems in the art are beneficial. The present disclosure particularly aims at improving the manufacturing process of solar cell arrangements, such as shingled solar cell arrangements.

SUMMARY

[0005] According to an embodiment, a method of processing a substrate used for the manufacture of a solar cell arrangement is provided. The method includes providing a substrate having a conductive pattern formed thereon. The method includes providing a current transportation wire having a first height at a bulk portion of the current transportation wire and a second height at an end portion of the current transportation wire. The second height is smaller than the first height. The method includes attaching the current transportation wire to the first side of the substrate in a manner such that the conductive pattern is electrically connected to the current transportation wire. The method includes providing a screen over the substrate, the screen having an opening or set of openings. The method includes transferring a printing material from the screen to the substrate through the opening or set of openings to print a first feature on the first side of the substrate next to the end portion of the current transportation wire.

[0006] According to a further embodiment, a method of processing a substrate used for the manufacture of a solar cell arrangement is provided. The method includes providing a substrate. A conductive pattern and a current transportation wire are disposed on the substrate. The conductive pattern is electrically connected to the current transportation wire. The current transportation wire has a first height at a bulk portion of the current transportation wire and a second height at an end portion of the current transportation wire, the second height being smaller than the first height. The method includes transferring a printing material from a screen to the substrate to print a first feature on the substrate next to the end portion of the current transportation wire.

[0007] According to a further embodiment, a photovoltaic device is provided. The photovoltaic device includes a substrate. The photovoltaic device includes a conductive pattern disposed on the substrate. The photovoltaic device includes a current transportation wire disposed on, in particular attached to, the substrate. The current transportation wire is connected to the conductive pattern. The current transportation wire has a first height at a bulk portion of the current transportation wire and a second height at an end portion of the current transportation wire. The second height is smaller than the first height. The photovoltaic device includes a first feature including a conductive paste disposed on the substrate next to the end portion of the current transportation wire.

[0008] According to a further embodiment, an apparatus for processing a substrate used for the manufacture of a solar cell arrangement is provided. The apparatus includes a first processing station for attaching a current transportation wire to the substrate. The substrate has a conductive pattern formed on the substrate. The current transportation wire is attached to the substrate in a manner such that the conductive pattern is electrically connected to the current transportation wire. The current transportation wire has a first height at a bulk portion of the current transportation wire and a second height at an end portion of the current transportation wire, the second height being smaller than the first height. The apparatus includes a second processing station including a printer. The printer includes a screen having an opening or set of openings. The printer is configured to transfer a printing material from the screen to the substrate through the opening or set of openings to print a first feature on the substrate next to the end portion of the current transportation wire.

[0009] According to a further embodiment, an apparatus for shaping an end portion of a conductive wire piece for a solar cell is provided. The apparatus includes a stamp for applying a pressing force to a portion of a conductive wire to separate the conductive wire into at least two conductive wire pieces including a first conductive wire piece, the stamp having a tapered contact surface for impacting the conductive wire to shape an end portion of the first conductive wire piece, the end portion tapering downwardly so that a height of the first conductive wire piece is reduced at the end portion.

[0010] Embodiments are also directed at apparatuses for carrying out the disclosed methods and include apparatus parts for performing each described method aspect. These method aspects may be performed by way of hardware components, a computer programmed by appropriate software, by any combination of the two or in any other manner. Furthermore, embodiments according to the disclosure are also directed at methods for operating the described apparatus. The methods for operating the described apparatus include method aspects for carrying out every function of the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] A full and enabling disclosure to one of ordinary skill in the art is set forth more particularly in the remainder of the specification including reference to the accompanying drawings wherein:

FIG. 1 shows an example of a substrate used for the manufacture of a solar cell including a conductive pattern formed thereon;

FIGs. 2-3 show an example of a current transportation wire having an end portion with a reduced height; FIGs. 4-8 illustrate a process in which a current transportation wire is attached to a substrate and a first feature is printed next to an end portion of the current transportation wire;

FIG. 9 shows an example of a solar cell including a current transportation wire and a first feature printed next to the current transportation wire;

FIG. 10 shows a screen for printing a first feature on a substrate;

FIG. 11 shows a scribed portion formed in a substrate having a current transportation wire and a printed first feature disposed on the substrate;

FIG. 12 illustrates a cleaving of a solar cell into solar cell pieces;

FIG. 13 shows an example of a solar cell piece including a current transportation wire and a first feature printed next to an end portion of the current transportation wire;

FIG. 14 shows an example of a solar cell arrangement including a plurality of partially overlapping solar cell pieces;

FIGs. 15-17 show examples of current transportation wires having an end portion with a reduced height;

FIG. 18 shows an example of a screen having a step-like profile at a bottom side of the screen;

FIGs. 19-22 show examples of a processing station for forming a current transportation wire having an end portion with a reduced height; and

FIG. 23 shows an apparatus for processing a substrate used for the manufacture of a solar cell arrangement according to embodiments described herein.

DETAILED DESCRIPTION

[0012] Reference will now be made in detail to the various embodiments, one or more examples of which are illustrated in the figures. Within the following description of the drawings, the same reference numbers refer to same components. Generally, only the differences with respect to individual embodiments are described. Each example is provided by way of explanation and is not meant as a limitation. Further, features illustrated or described as part of one embodiment can be used on or in conjunction with other embodiments to yield yet a further embodiment. It is intended that the description includes such modifications and variations.

[0013] The drawings are schematic drawings which are not drawn to scale. Some elements in the drawings may have dimensions which are exaggerated for the purpose of highlighting aspects of the present disclosure and/or for the sake of clarity of presentation.

[0014] Embodiments described herein relate to the manufacturing of a solar cell arrangement including a plurality of solar cell pieces that are connected to each other in a partially overlapping, or cascading, manner (“shingled solar cell arrangement”). A solar cell piece, also called “shingle”, can be understood as a piece of material that is obtained by separating a full solar cell into multiple smaller pieces. For example, a full solar cell can be a substantially square solar cell (possibly with rounded or chamfered edges). A full solar cell can be separated, i.e. spit or cleaved, into a plurality (such as three, four, five, six or even more) of solar cell pieces. A solar cell piece may be a strip of material that may be substantially rectangular shaped. In a shingled solar cell arrangement, multiple solar cell pieces are electrically and mechanically connected to each other. A mechanical connection between two adjacent solar cell pieces in the solar cell arrangement can be provided by an adhesive which may be disposed in an overlapping region of the two solar cell pieces. Likewise, an electrical connection between two adjacent solar cell pieces can be provided by a conductive material which is disposed in the overlapping region. In some embodiments, an electrically conductive adhesive (ECA) may be used for providing both a mechanical and an electrical connection at the same time. In other embodiments, the adhesive and the conductive paste may be separate materials.

[0015] A conductive material for electrically connecting adjacent solar cell pieces and/or an adhesive material for mechanically connecting adjacent solar cell pieces, or an ECA for providing both the electrical and mechanical connection, can be printed on a substrate used for the manufacture of a solar cell arrangement. Specifically, the printing can be screen printing. The material can be printed on a full solar cell, after which the solar cell may be separated into smaller solar cell pieces (“print on cell”). Alternatively, the solar cell may be cleaved first, and the material can thereafter be printed on the resulting solar cell pieces (“Print on Shingle”). [0016] The term “screen printing” as used herein refers to a printing process where a printing material, e.g. a printing paste that may be adhesive and/or conductive, is transferred from a screen to a substrate for printing one or more features on the substrate. The screen has an opening or set of openings, i.e. through-holes, formed therein. The printing material is transferred from the screen to the substrate through the openings. The term “screen” refers to a piece of material having such an opening or set of openings for transferring the printing material therethrough. A screen as described herein can be a mesh screen or a stencil. A mesh screen may include an emulsion and a wire mesh, wherein openings are formed in the emulsion to allow the printing material to pass there through. A stencil can be a rigid piece of material, e.g. a metal stencil, with openings formed therein.

[0017] A substrate as described herein may be a substrate used for the manufacture of a solar cell arrangement. A substrate may be a semiconductor substrate, such as a silicon substrate. The substrate can be a wafer, such as a semiconductor wafer. The substrate can be a substrate of a full solar cell or a substrate of a solar cell piece, obtained after cleaving of a full solar cell.

[0018] The substrate has a conductive pattern formed thereon, such as a plurality of fingers. A current transportation wire, e.g. a thin metal wire, is attached to the substrate, for example by soldering. The current transportation wire may perform the function of a busbar. That is to say, like a busbar, the current transportation wire may be configured to transport an electrical current that is collected by the conductive pattern.

[0019] A first feature is screen printed on the substrate. The first feature may be a material, e.g. a paste, that is conductive and/or adhesive, for example an EC A, for providing an electrical and/or mechanical connection in a solar cell arrangement as described above. For ensuring the quality of the electrical and/or mechanical connection provided by the first feature in the solar cell arrangement, it is beneficial to print the first feature close to an end portion, i.e. an extremity, of the current transportation wire. For example, the first feature may be printed within a distance of 10 mm or less, more particularly 5 mm or less, from the end portion of the current transportation wire. The current transportation wire has a certain height above the substrate (e.g. a height of about 200 pm). In some systems, said height may prevent the screen (e.g. a stencil or mesh screen) that is used for screen printing the first feature from moving sufficiently close to the substrate in the vicinity of the end portion of the current transportation wire. In other words, a vertical distance above the substrate that is reachable by the screen in the vicinity of the current transportation wire may be too high due to the height of the current transportation wire. A vertical distance that is too high may result in a poor printing precision of the printed first feature. According to embodiments described herein, the end portion of the current transportation wire is provided with a reduced height. The current transportation wire is shaped such that the height of the current transportation wire at the end portion is smaller than the height at the bulk of the current transportation wire (bulk height or nominal height). For example, the reduced height at the end portion may be 100 pm or less. The reduced height at the end portion allows the screen to move further down, i.e., closer to the substrate, in the vicinity of the end portion. The first feature can be printed with high precision next to the end portion of the current transportation wire.

[0020] Fig. 1 shows an example of a substrate 10 having a conductive pattern 20 formed on a first side of the substrate 10. The substrate 10 may be a substrate used for the manufacture of a solar cell. The substrate may be an unfinished solar cell. The substrate may be a semiconductor substrate, such as a silicon substrate. The first side, or first surface, of the substrate 10 may be the front side or back side of the substrate 10. The conductive pattern 20 may be a printed pattern, for example printed on the substrate by screen printing. The conductive pattern 20 may include a plurality of fingers.

[0021] Fig. 2 shows an example of a current transportation wire 200. A current transportation wire 200 may be configured to be attached, e.g. soldered, to the first side of the substrate 10 in a manner such that the current transportation wire 200 contacts at least a portion of the conductive pattern 20. The current transportation wire 200 may contact at least one finger of the conductive pattern 20. The current transportation wire 200 may be configured for transporting a current collected by the conductive pattern 20, e.g. a plurality of fingers.

[0022] A current transportation wire 200 may be configured to function as a busbar of a solar cell. That is to say, as regards the function, the current transportation wire 200 has a similar role to a conventional busbar. Still, a current transportation wire 200 is different from a busbar as regards the material that is used for a current transportation wire 200 as compared to a busbar. A busbar is normally formed by depositing, such as printing, a material (e.g. a paste) on a substrate. A current transportation wire 200 is not a printed or otherwise deposited material, in the sense that the current transportation wire 200 is not deposited in a deposition process. A current transportation wire is a length of conductive wire, e.g. a metal wire, that can be obtained by cutting a piece from a longer conductive wire. A current transportation wire is a stand-alone object that can be picked up, moved and otherwise handled, and that has dimensions such as a length, width and height, independent of any substrate. A current transportation wire may be attached to a substrate by a bonding agent, such as solder, and is not printed on a substrate. In comparison, a busbar is not a stand-alone object. A busbar is material that is deposited in a deposition process and only exists in combination with the substrate on which the busbar is deposited.

[0023] The current transportation wire 200 may have a bulk portion 210, an end portion 220 and/or an end portion 230. An end portion, such as the end portion 220 or the end portion 230, of the current transportation wire 200 can be understood as a short portion of the current transportation wire 200 at an end or extremity of the current transportation wire 200. An end portion can have a length of a few millimeters up to, for example, about 1 cm. An end portion can have a length of 5% or less of a total length of the current transportation wire. The bulk portion 210, or major portion, can be understood as the portion of the current transportation wire 200 that is obtained by subtracting the two end portions 220 and 230. The end portion 220 and/or the end portion 230 may not belong to the bulk portion 210. The majority of the material of the current transportation wire 200 belongs to the bulk portion 210. The bulk portion can have a length which is 90% or more of a total length of the current transportation wire 200.

[0024] Fig. 3 shows a portion of a current transportation wire 200. According to embodiments described herein, a height of the current transportation wire 200 is a varying, i.e. non-constant, height, that varies along the length of the current transportation wire 200. The term “height”, as used herein, can be understood as a thickness of the current transportation wire 200 in a vertical direction. The height of the current transportation wire 200 is apparent, for example, after the current transportation wire 200 has been attached to the substrate 10. The height can be understood as the height, or vertical thickness, of the current transportation wire 200 above a horizontally oriented substrate 10 on which the current transportation wire 200 has been attached.

[0025] The current transportation wire 200 may have a first height 310 at the bulk portion 210. The first height 310 may be referred to as the bulk height of the current transportation wire 200. The first height 310 may be a nominal height or average height of the bulk portion. The height of the current transportation wire may be substantially equal to the first height 310 across the entire bulk portion 210, up to for example manufacturing tolerances. [0026] The current transportation wire 200 may have a reduced height at the end portion 220. The current transportation wire 200 may have a second height 320 at the end portion 220. The second height 320 may be smaller than the first height 310. The second height 320 may be 70% or less, more particularly 40% or less, still more particularly 10% or less, of the first height 310. The end portion 220 may have a tapered shape having a downward slope. The end portion 220 may have a height that gradually decreases from the first height 310 to the second height 320.

[0027] Returning to Fig. 2, the height of the current transportation wire 200 at the end portion 230 may be substantially equal to the bulk height, i.e. the first height 310, so that the end portion 230 may not have reduced height. In other embodiments, the end portion 230 may have a reduced height, similar to the end portion 220.

[0028] Fig. 4 shows a substrate 10. The substrate shown in Fig. 4, and likewise the substrate shown in the other figures, may be disposed in a horizontal orientation. A horizontal orientation may include a deviation from an exactly horizontal orientation by up to 15 degrees. The substrate 10 may have a conductive pattern 20 (not shown in Fig. 4) formed on a first side 402 of the substrate 10. The substrate may be supported by a substrate support (not shown), e.g. a chuck (such as a vacuum chuck or electrostatic chuck), a conveyor, or another support.

[0029] As shown in Fig. 5, the current transportation wire 200 may be attached to the first side 402 of the substrate 10, e.g. by soldering. A bonding agent, such as solder, may bond the current transportation wire 200 to the substrate 10. The current transportation wire 200 has an end portion 220 having a reduced height as compared to the bulk height of the current transportation wire 200, as described herein.

[0030] As shown in Fig. 6, a screen 610 may be provided over the substrate 10 after attaching the current transportation wire 200 to the substrate 10. The screen 610 may be provided in a horizontal orientation. Providing the screen over the substrate may include moving the substrate to a position below the screen, moving the screen to a position over the substrate, or a combination thereof. The screen 610 may be a mesh screen or a stencil. A printing material, such as a printing paste that is conductive and/or adhesive, may be disposed on the screen 610. The screen 610 may include an opening or a set of openings for letting the printing material pass therethrough for printing a first feature on the first side of the substrate 10.

[0031] Fig. 7 illustrates a screen printing operation for printing the first feature on the first side 402 of the substrate 10 after the current transportation wire 200 has been attached to the first side 402 of the substrate 10. A pressure application instrument 710, such as a squeegee or doctor blade, may move over the screen 610 to perform a printing stroke. In Fig. 7, the pressure application instrument 710 moves from left to right to perform the printing stroke. During the printing stroke, the pressure application instrument 710 exerts a downward pressure on the screen 610 to urge the printing material through the opening or set of openings of the screen 610 for printing the first feature. A downward pressure applied by the pressure application instrument 710 can be provided by an actuator 720 connected to the pressure application instrument 710. The actuator 720, e.g. a linear motor, can cause the pressure application instrument 710 to move downward. The pressure applied to the screen by the pressure application instrument 710 may be controlled by a controller 730 that may be connected to the actuator 720.

[0032] According to embodiments described herein, the first feature may be printed next to, or adjacent to, the end portion 220. For example, the distance between the first feature and the end portion 220 may be 10 mm or less, particularly 5 mm or less or even 3 mm or less. In light thereof, the opening or set of openings of the screen 610 for printing the first feature will likewise be very close to the end portion 220, e.g. at a distance of 10 mm or less, 5 mm or less or even 3 mm or less. Since the screen 610 has a certain degree of flexibility, the screen will bend downward due to the pressure applied to the screen by the pressure application instrument 710. The reduced height of the current transportation wire 200 at the end portion 220 allows the screen 610 to come closer to the substrate 10 in the vicinity of the end portion 220, that is to say, at the location where the first feature is to be printed. As illustrated in Fig. 7, the screen 610 may be pressed against a downward sloping surface of the end portion 220 to allow the screen to move downward towards the substrate 10. A vertical distance 750 between the screen 610 and the substrate 10 next to the end portion 220 may be small, for example 100 pm or less. The vertical distance 750 may be a distance between the substrate 10 and the opening or set of openings that are used to print the first feature. The vertical distance 750 is smaller than the first height 310, i.e. the bulk height, of the current transportation wire 200. For example, the vertical distance 750 may be 50% or less, particularly 20% or less, or even 1% or less, of the first height 310. The vertical distance 750 may be comparable, i.e. substantially equal, to the second height 320. Since the screen can move very near to the surface of the substrate 10, the first feature can be printed next to the end portion 220 with a high precision.

[0033] That the first feature is printed “next to the end portion 220”, “adjacent to the end portion” or “in the vicinity of the end portion 220” can be understood in the sense that the first feature is printed in a region of the substrate that is sufficiently close to the end portion 220 so that the beneficial effect of the reduced height of the end portion on the vertical distance 750 that can be reached by the screen is noticeable. As described above, when the first feature is printed within a small distance from the end portion 220, the reduced height of the end portion 220 will allow the screen to move closer to the substrate than in a situation where the end portion does not have a reduced height, so that the reduced height at the end portion results in a higher printing precision of the first feature. In light thereof, the terminology “next to the end portion 220”, “adjacent to the end portion” or “in the vicinity of the end portion 220”, can be understood as referring to a distance range where such benefits of the reduced height of the end portion are noticeable. The specific numerical value of such a distance range may depend on the numerical values of the first height 310 and the second height 320 of the current transportation wire 200. For example, for a current transportation wire having a bulk height (first height 310) of about 200 pm and a second height 320 of about 100 pm or less, the reduced height at the end portion 220 can result in a higher printing precision when the first feature is printed within a distance range of 10 mm or less from the end portion 220.

[0034] According to embodiments described herein, the terminology “next to the end portion 220”, “adjacent to the end portion” or “in the vicinity of the end portion 220” can be understood in the sense that a distance between the first feature and the end portion 220 is 10 mm or less, or even 5 mm or less.

[0035] Fig. 8 shows the first feature 810 that has been printed on the first side 402 of the substrate next to the end portion 220. A distance 850 between the first feature 810 and the end portion 220 may be 10 mm or less. The first feature 810 may have a height that is smaller than the first height 310 of the current transportation wire 200. For example, the height of the first feature 810 may be comparable to the vertical distance 750.

[0036] The first feature 810 may be a paste, such as a conductive paste. The first feature 810 may be a conductive and/or adhesive material. The first feature 810 may be configured to provide at least one of an electrical and a mechanical connection between adjacent solar cell pieces of a solar cell arrangement. The solar cell arrangement may include a plurality of partially overlapping solar cell pieces.

[0037] Fig. 9 shows a solar cell 1 that may result from the operations described above. The solar cell 1 may include the substrate 10. The conductive pattern 20 may be formed on the first side 402 of the substrate 10. The current transportation wire 200 may be attached to the first side 402 of the substrate 10. A plurality of further current transportation wires 200a may likewise be attached to the first side 402 of the substrate 10. Each current transportation wire 200a may be electrically connected, and may in particular contact, at least a portion of the conductive pattern 20. Each current transportation wire 200a may have an end portion having a reduced height, similar to the end portion 220 of the current transportation wire 200. The first feature 810 may be printed on the first side 402 of the substrate 10 next to the end portion 220 of the current transportation wire 200. Further features 810a like the first feature 810 may be formed on the first side 402 of the substrate 10. Each further feature 810a may have properties analogous to the above-described properties of the first feature 810. For example, each further feature 810a may be a material, e.g. a paste, that is conductive and/or adhesive. Each further feature 810a may be printed next to an end portion of a respective current transportation wire 200a.

[0038] Fig. 10 shows an example of a screen 610 that may be used for printing the first feature 810, and any potential further features 810a, on the substrate 10. The screen 610 may be a mesh screen or a stencil. The screen may have a set of openings 1010 (or a single opening 1010). The openings 1010 are through-holes of the screen 610. An opening 1010 may be configured for letting a printing material, e.g. a printing paste, pass therethrough for printing one or more features on the substrate 10. An opening 1010 may have a shape corresponding to a shape of a feature, such as the first feature 810, that is to be printed on the substrate 10 by transferring a printing material from the screen to the substrate 10 through said opening 1010.

[0039] In what was described above, the first feature 810 (and likewise the further features 810a) is printed on a full solar cell, i.e., before the solar cell is separated into solar cell pieces (“Print on cell”). In other embodiments, the solar cell may be cleaved, and thereafter the first feature 810 may be printed on a solar cell piece resulting from such cleaving of the solar cell (“Print on shingle”).

[0040] In the figures, the number of current transportation wires 200 and 200a, the number of fingers of the conductive pattern 20, as well as the spatial arrangement of said wires and fingers, is exemplary and the disclosure shall not be limited thereto.

[0041] In light of the above, according to an embodiment, a method of processing a substrate used for the manufacture of a solar cell arrangement is provided. The method includes providing a substrate having a conductive pattern formed on the substrate. The method includes providing a current transportation wire having a first height at a bulk portion of the current transportation wire and a second height at an end portion of the current transportation wire. The second height is smaller than the first height. The method includes attaching the current transportation wire to a first side of the substrate in a manner such that the conductive pattern is electrically connected to the current transportation wire. The method includes providing a screen over the substrate, the screen having an opening or set of openings. The method includes transferring a printing material from the screen to the substrate through the opening or set of openings to print a first feature on the first side of the substrate next to the end portion of the current transportation wire. The method may include any aspect or combination of aspects described above.

[0042] Embodiments described herein provide the advantage that, due to the reduced height of the end portion of the current transportation wire, the screen can move very close to the substrate in the vicinity of the end portion. The first feature can be printed next to the end portion with high precision. Further, the pressure needed for moving the screen downward in the vicinity of the end portion can be reduced, since the reduced height of the end portion provides more space for the screen to move downward. Further, in light of the reduced height, particularly the tapered shape, of the end portion, damage to the screen, such as a puncturing of the screen, that may be caused by pressing the screen against the end portion can be avoided or at least reduced.

[0043] The first feature may be disposed on the substrate within a distance of 10 mm or less, particularly 5 mm or less, from the end portion of the current transportation wire.

[0044] The first feature may be at least one of an electrically conductive material and an adhesive. The first feature may be an electrically conductive adhesive. The first feature may be a paste, such as a conductive paste, more specifically a conductive adhesive paste.

[0045] A method according to embodiments described herein may include applying a downward pressure to the screen for transferring the printing material from the screen to the substrate through the opening or set of openings, wherein the opening or set of openings may reach a vertical distance from the substrate, such as vertical distance 750. The vertical distance may be smaller than the first height of the current transportation wire at the bulk portion. The downward pressure may be applied by a pressure application instrument. [0046] The end portion of the current transportation wire may taper downwardly so that the height of the current transportation wire gradually decreases at the end portion.

[0047] Fig. 11 shows a scribed portion 1150 formed in the substrate 10. A scribed portion 1150 may be formed, for example, by a laser. The laser may direct a laser beam onto the substrate for scribing the substrate 10. A scribed portion 1150 may, for example, be a scribed line or a sequence of scribed dots arranged along a line. A scribed portion 1150, or a set of dotlike scribed portions, may have a linear shape extending in a direction that is substantially perpendicular to the direction of the current transportation wire 200. The scribed portion 1150 may be formed after the first feature 810 has been printed on the substrate 10 or before the first feature 810 has been printed on the substrate 10. The scribed portion 1150 may be formed after or before the current transportation wire 200 has been attached to the substrate 10. In Fig. 11, the scribed portion 1150 is formed on the first side 402 of the substrate 10. In other embodiments, a scribed portion may be formed on a second side of the substrate 10 opposite the first side 402.

[0048] The scribed portion 1150 indicates an intended breaking region, such as a breaking line, where the substrate 10 will be broken, or cleaved or split, into smaller pieces in a subsequent cleaving operation. The current transportation wire 200 and the first feature 810 may be disposed on a same side of the scribed portion 1150 (for example, in Fig. 11, the current transportation wire 200 and the first feature 810 are both disposed on the left side of the scribed portion 1150), reflecting that the current transportation wire 200 and the first feature 810 may be part of a same solar cell piece after the cleaving operation.

[0049] A method according to embodiments described herein may include scribing the substrate. The current transportation wire and the first feature may be disposed on a same side of a scribed portion, such as a scribed line, of the substrate.

[0050] Fig. 12 illustrates a cleaving of a solar cell 1. The solar cell 1 may be the solar cell shown in Fig. 9. The solar cell 1 may include scribed portions 1212 and 1214, such as scribed lines. A cleaving operation may be performed to separate or split the solar cell 1 into solar cell pieces, such as solar cell pieces 1222, 1224 and 1226. A cleaving operation may include applying a force to the solar cell 1 at the scribed portions 1212 and 1214 to break the solar cell at the scribed portions. In Fig. 12, the number of scribed portions, and the resulting number of solar cell pieces, is exemplary and the disclosure shall not be limited thereto. [0051] Fig. 13 shows an example of a solar cell piece 1222 that may result from cleaving the solar cell 1. The solar cell piece 1222 may include a substrate piece 1310. The substrate piece 1310 may be a piece, or part, of the substrate 10 that is obtained by cleaving the substrate 10, more specifically by cleaving the substrate 10 at a scribed portion. The solar cell piece 1222 may include a portion of the conductive pattern 20, for example a subset of fingers of the conductive pattern 20. The solar cell piece 1222 may include the current transportation wire 200 and the first feature 810 formed next to the end portion 220 of the current transportation wire 200 as described herein. The solar cell piece 1222 may include one or more further current transportation wires 200a and/or one or more further features 810a.

[0052] A method according to embodiments described herein may include separating, or cleaving, the substrate into two or more solar cell pieces including a first solar cell piece. The two or more solar cell pieces may include three, four, five or more solar cell pieces. The substrate may be cleaved at a scribed portion, or a plurality of scribed portions, of the substrate. The first solar cell piece may be the solar cell piece 1222. The current transportation wire and the first feature may be disposed on the first solar cell piece. The current transportation wire and the first feature may be disposed on a same solar cell piece.

[0053] Fig. 14 shows a solar cell arrangement 1400 including a plurality of partially overlapping solar cell pieces. Each solar cell piece of the solar cell arrangement 1400 may partially overlap with an adjacent solar cell piece of the solar cell arrangement 1400. The solar cell arrangement 1400 may include the solar cell piece 1222. The solar cell arrangement 1400 may include further solar cell pieces 1420. A further solar cell piece 1420 may originate from cleaving the substrate 10, i.e. the same substrate 10 from which the solar cell piece 1222 was obtained, or from cleaving a different substrate. The first feature 810 may be configured for connecting the solar cell piece 1222 to an adjacent solar cell piece 1420 of the solar cell arrangement 1400. The connection provided by the first feature 810 may be an electrical connection or a mechanical connection, or both. A mechanical connection may be provided in case the first feature 810 is or includes an adhesive material for bonding the solar cell piece 1222 to the adjacent solar cell piece 1420. An electrical connection may be provided in case the first feature 810 is or includes a conductive material. The first feature may be an ECA for providing both an electrical and a mechanical connection. The first feature 810 may be disposed in an overlap region of the solar cell piece 1222 and the adjacent solar cell piece 1420. If the first feature provides an electrical connection without providing a mechanical connection, an adhesive may additionally be provided in the overlap region for bonding the solar cell piece 1222 to the adjacent solar cell piece 1420. If the first feature provides a mechanical connection without providing an electrical connection, a conductive material may be additionally provided in the overlap region for electrically connecting the solar cell piece 1222 to the adjacent solar cell piece 1420. Features 1410 similar to the first feature 810 (e.g. the features 1410 may be ECAs) may connect adjacent solar cell pieces in the solar cell arrangement 1400.

[0054] The method according to embodiments described herein may include bonding the first solar cell piece (such as the solar cell piece 1222) to a second solar cell piece (such as a solar cell piece 1420 adjacent to the solar cell piece 1222) in a manner such that the first solar cell piece and the second solar cell piece partially overlap. The first feature may be disposed in an overlap region of the first solar cell piece and the second solar cell piece. The bonding may be provided by the first feature and/or by one or more adhesives that may be disposed in the overlap region of the first solar cell piece and the second solar cell piece.

[0055] Figs. 15-17 show further examples of current transportation wires 200 having an end portion 220 with a reduced height according to embodiments described herein. Fig. 15 shows that the end portion 220 may have a step-like shape. Fig. 16 shows that the end portion 220 may have a tapered shape that includes a curved, or concave, downward slope. Fig. 17 shows that the end portion 220 may slope downward to form a sharp tip, so that the second height 320 is equal to zero.

[0056] Fig. 18 shows a screen 610 provided over a substrate 10 after the current transportation wire 200 has been attached to the substrate 10. The screen 610 in Fig. 18 may be a stencil. The screen 610 may have a step-like vertical profile including a high portion 1812 and a low portion 1814. The high portion 1812 may be disposed over, or may rest upon, at least a portion of the current transportation wire 200. The low portion 1814 may face the substrate 10, more specifically may face a region of the substrate 10 where the current transportation wire 200 is not disposed. The high portion 1812 may have a higher height, or vertical distance, with respect to the substrate 10 than the low portion 1814. The difference in height between the high portion 1812 and the low portion 1814 may be provided to at least partially compensate for the fact that the height of the current transportation wire 200 prevents the screen from moving downward toward the substrate 10. At the low portion 1814, the screen 610 is closer to the substrate 10 than at the high portion 1812. The opening or set of openings for printing the first feature on the substrate 10 may be formed in the low portion 1814 of the screen 610. In light thereof, the opening or set of openings are closer to the substrate 10 as compared to a screen 610 where the entire screen has a height equal to the height of the high portion. The step-like vertical profile of the screen 610 has the benefit that the distance between the screen 610 and the substrate 10 can be reduced at the low portion 1814. Further, similar to what was described above, due to the reduced height of the end portion 220, the low portion 1814 of the screen 610 will be able to bend downward towards the substrate 10 when pressure is applied to the screen 610 by a pressure application instrument, further reducing the vertical distance between the opening or set of openings and the substrate 10. The first feature 810 can be printed with high precision.

[0057] A screen as described herein may include a high portion and a low portion. The high portion and the low portion may form a step-like vertical profile of a bottom side of the screen. The high portion may be configured to contact the current transportation wire. The low portion may be configured to face the substrate in a region spaced apart from the current transportation wire. The opening or set of openings for printing the first feature may be formed in the low portion. A vertical distance between the low portion and the substrate may be smaller than a vertical distance between the high portion and the substrate.

[0058] Figs. 19-20 illustrate a processing station 1900 for forming a current transportation wire 200 having an end portion with a reduced height as described herein. The processing station may include a support 1940 for supporting a conductive wire 1950. The support 1940 may have a supporting surface 1942 for supporting the conductive wire 1950. The support 1940, particularly the supporting surface 1942, may include an opening 1945, or through-hole.

[0059] The conductive wire 1950 may be a long piece of wire that may be fed, for example, from the right-hand side of the figure towards the left. The conductive wire 1950 may move from right to left until the conductive wire has reached the position shown in Fig. 19, after which the movement of the conductive wire may be stopped, so that the conductive wire can be processed.

[0060] The processing station 1900 may include a stamp 1920. The stamp 1920 may be disposed above the support 1940. The stamp 1920 may have a first tapered surface 1922 and/or a second tapered surface 1924. The first tapered surface and/or the second tapered surface may be tapered contact surfaces. The first tapered surface 1922 and/or the second tapered surface 1924 may be inclined at an angle with respect to a horizontal direction and/or with respect to the supporting surface 1942 of the support 1940. The stamp 1920 may include a protrusion 1926 projecting downward from the stamp 1920. The protrusion 1926 may adjoin the first tapered surface 1922 and/or the second tapered surface 1924. The protrusion may face the supporting surface 1942. The protrusion 1926 may face the opening 1945. At least a portion of the protrusion 1926 may be configured to fit into the opening 1945.

[0061] The stamp 1920 may be movable upward and/or downward. In operation, the stamp 1920 may move downward to the support 1940, as shown in Fig. 20. The protrusion 1926 may impinge onto the conductive wire 1950, resulting in the conductive wire 1950 being cut into a first conductive wire piece 2052 and a second conductive wire piece 2054. In such a cutting operation, at least a portion of the protrusion 1926 may move into the opening 1945, resulting in the creation of a small conductive wire piece 2060, which is an excess or scrap piece of wire that can be dispensed with. As the protrusion cuts the conductive wire 1950 into two smaller pieces, the first tapered surface 1922 and/or the second tapered surface 1924 may press down on the respective end portions of the two conductive wire pieces, resulting in the formation of end portions having a reduced height as described herein. For example, the first conductive wire piece 2052 may be the current transportation wire 200 having an end portion 220 with a reduced height as described herein. Alternatively, the first conductive wire piece 2052 may be further processed to form the current transportation wire 200. For example, a portion of the first conductive wire piece 2052 on the left-hand side of the first conductive wire piece 2052 may be cut away before the current transportation wire 200 is ultimately obtained. Likewise, the first conductive wire piece 2052 may be subj ect to further treatment before the current transportation wire 200 in a final form is ultimately obtained.

[0062] Figs. 21-22 show another example of a processing station 1900. The stamp 1920 may be configured for cutting the conductive wire 1950 into smaller conductive wire pieces without generating a piece of scrap wire. The first tapered surface 1922 and the second tapered surface 1924 may be adjoining surfaces. The stamp may have a tip portion 2126, or edge portion, for cutting the conductive wire 1950. The tip portion 2126 may be formed in a region where the first tapered surface 1922 and the second tapered surface 1924 meet, or join, each other. When the stamp 1920 moves downward to impinge onto the conductive wire 1950, the tip portion 2126 may cut the conductive wire 1950 into two conductive wire pieces, without creating a piece of scrap wire. The first tapered surface 1922 and the second tapered surface 1924 press down onto the conductive wire 1950 to form respective end portions having a tapered shape, as described above. [0063] In light of the above, a stamp may be provided which is configured for both cutting a conductive wire into two or more conductive wire pieces and for shaping end portions of the conductive wire pieces having a reduced height in a same movement of the stamp.

[0064] The method according to embodiments described herein may include providing a conductive wire (e.g. conductive wire 1950). The method may include applying a pressing force to a portion of the conductive wire using a stamp to separate the conductive wire into at least two conductive wire pieces including a first conductive wire piece (e.g. conductive wire piece 2052). The stamp may have a tapered contact surface for impacting the conductive wire to shape an end portion of the first conductive wire piece. The first conductive wire piece may be the current transportation wire 200 as described herein or the current transportation wire 200 may be formed by further processing the first conductive wire piece. The end portion of the first conductive wire piece may be the end portion of the current transportation wire having the second height as described herein.

[0065] According to a further embodiment, a method of processing a substrate used for the manufacture of a solar cell arrangement is provided. The method includes providing a substrate. A conductive pattern and a current transportation wire are disposed on the substrate. The conductive pattern is electrically connected to the current transportation wire. The current transportation wire has a first height at a bulk portion of the current transportation wire and a second height at an end portion of the current transportation wire, the second height being smaller than the first height. The method includes transferring a printing material from a screen to the substrate to print a first feature on the substrate next to the end portion of the current transportation wire. The method may include any aspect, or any combination of aspects, of the method described above. The substrate may be a substrate of a full solar cell, i.e. before cleaving the solar cell, such as the substrate 10 shown in the figures. In such a case, the printing of the first feature on the substrate may be a “Print on cell” process as described herein. Alternatively, the substrate may be a substrate piece obtained after cleaving a solar cell into smaller solar cell pieces. In such a case, the printing of the first feature on the substrate may be a “Print on shingle” process as described herein.

[0066] According to a further embodiment, a photovoltaic device is provided. The photovoltaic device includes a substrate. The photovoltaic device includes a conductive pattern disposed on the substrate. The photovoltaic device includes a current transportation wire disposed on, in particular attached to, the substrate. The current transportation wire is connected to the conductive pattern. The current transportation wire has a first height at a bulk portion of the current transportation wire and a second height at an end portion of the current transportation wire. The second height is smaller than the first height. The photovoltaic device includes a first feature including a conductive paste disposed on the substrate next to the end portion of the current transportation wire. The photovoltaic device may result from performing a method according to any of the embodiments described above, and may accordingly include any feature or combination of features that result from performing said methods. The substrate may be a substrate of a full solar cell, i.e. before a cleaving the solar cell is performed, such as the substrate 10 shown in the figures. In such case, the photovoltaic device may be a solar cell. Alternatively, the substrate may be a substrate piece obtained after cleaving a solar cell into smaller solar cell pieces. In such case, the photovoltaic device may be a solar cell piece.

[0067] Fig. 23 shows an apparatus 2300 for processing a substrate used for the manufacture of a solar cell arrangement, more specifically a solar cell arrangement including a plurality of partially overlapping solar cell pieces.

[0068] The apparatus 2300 may include processing station 1900 as described herein. The processing station 1900 may be configured for forming a current transportation wire 200 having an end portion 220 with a reduced height, as described herein.

[0069] The apparatus 2300 may include a processing station 2310 for attaching the current transportation wire 200 to a first side 402 of the substrate 10. The processing station 2310 may include a support for supporting the substrate 10. The processing station 2310 may include an arm having a gripper at an end of the arm for gripping the current transportation wire 200 and for attaching the current transportation wire 200 to the first side 402 of the substrate 10. The processing station 2310 may include a bonding agent dispenser for dispensing a bonding agent, such as solder. The bonding agent may be used for attaching the current transportation wire 200 to the substrate 10.

[0070] The apparatus 2300 may include a processing station 2320, or printing station, for screen printing the first feature 810 on the substrate 10. The processing station 2320 may include a support for supporting the substrate 10. The processing station 2320 may include a printer. The printer may include a screen 610 having an opening or set of openings. The printer may include a pressure application instrument 710 as described herein, an actuator 720 as described herein, and/or a controller 730 as described herein. The printer may be configured to transfer a printing material from the screen 610 to the substrate 10 through the opening or set of openings to print the first feature 810 on the first side 402 of the substrate 10 next to the end portion 220 of the current transportation wire 200.

[0071] The apparatus 2300 may include a processing station 2330, or scribing station, for scribing the substrate 10. The processing station 2330 may include a support for supporting the substrate 10. The processing station 2330 may include a laser for scribing the substrate 10.

[0072] The apparatus 2300 may include a processing station 2340, or cleaving station, for separating the substrate 10 into two or more solar cell pieces including a first solar cell piece (for example, solar cell piece 1222). The first solar cell piece may include the current transportation wire 200 and the first feature 810. The processing station 2340 may include a support for supporting the substrate 10. The processing station 2340 may include a cleaving apparatus for cleaving the substrate 10.

[0073] The apparatus 2300 may include a processing station 2350, or assembling station, for forming a solar cell arrangement including a plurality of partially overlapping solar cell pieces, for example the solar cell arrangement 1400 as described herein. The processing station 2350 may be configured for connecting the first solar cell piece (for example, solar cell piece 1222) to a second solar cell piece (for example, solar cell piece 1420) in a manner such that the first solar cell piece and the second solar cell piece partially overlap. The first feature may be disposed in an overlap region of the first solar cell piece and the second solar cell piece. The processing station 2350 may include a support for supporting a plurality of solar cell pieces. The processing station 2350 may include an arm having a gripper at the end of the arm for positioning the solar cell pieces in an overlapping manner to form the solar cell arrangement.

[0074] The apparatus 2300 may include a further processing station, such as a curing station, for curing the adhesives that are used for connecting adjacent solar cell pieces in the solar cell arrangement.

[0075] As shown in Fig. 23 by the lines connecting adjacent processing stations, processing station 2310 may be downstream of processing station 1900; processing station 2320 may be downstream of processing station 2310; and so on. The order of some of the processing stations may be interchanged. For example, processing station 2330 (scribing station) may be upstream of processing station 2320 or even upstream of processing station 1900. [0076] According to a further embodiment, an apparatus for processing a substrate used for the manufacture of a solar cell arrangement is provided. The apparatus includes a first processing station (such as processing station 2310) for attaching a current transportation wire to the substrate. The substrate has a conductive pattern formed thereon. The current transportation wire is attached to the substrate in a manner such that the conductive pattern is electrically connected to the current transportation wire. The current transportation wire has a first height at a bulk portion of the current transportation wire and a second height at an end portion of the current transportation wire, the second height being smaller than the first height. The apparatus includes a second processing station (such as processing station 2320) including a printer. The printer includes a screen having an opening or set of openings. The printer is configured to transfer a printing material from the screen to the substrate through the opening or set of openings to print a first feature on the substrate next to the end portion of the current transportation wire. The apparatus may include any feature, and any combination of features, of the apparatus 2300 described herein. The apparatus may be configured for performing any aspects, and any combinations of aspects, of the methods according to embodiments described above.

[0077] An apparatus according to embodiments described herein may include a pressure application instrument. The apparatus may include an actuator connected to the pressure application instrument. The apparatus may include a controller connected to the actuator. The controller may be configured to control the actuator to move the pressure application instrument downward to apply a pressure to the screen for transferring the printing material from the screen to the substrate through the opening or set of openings, such that the opening or set of openings reach a vertical distance from the substrate, the vertical distance being smaller than the first height of the current transportation wire at the bulk portion.

[0078] An apparatus according to embodiments described herein may include a third processing station (such as processing station 1900) for forming the current transportation wire. The third processing station may include a stamp for applying a pressing force to a portion of a conductive wire to separate the conductive wire into at least two conductive wire pieces including a first conductive wire piece. The first conductive wire piece may be the current transportation wire. The stamp may have a tapered contact surface for impacting the conductive wire to form the end portion of the current transportation wire. [0079] An apparatus according to embodiments described herein may include a scribing station (such as processing station 2330) for scribing the substrate. The scribing station may be configured for forming a scribed portion on the first side of the substrate. The current transportation wire and the first feature may be disposed on a same side of the scribed portion.

[0080] An apparatus according to embodiments described herein may include a cleaving station (such as processing station 2340) for separating the substrate into two or more solar cell pieces including a first solar cell piece. The first solar cell piece may include the current transportation wire and the first feature.

[0081] An apparatus according to embodiments described herein may include an assembling station (such as processing station 2350) for forming a solar cell arrangement including a plurality of partially overlapping solar cell pieces. The assembling station may be configured for connecting the first solar cell piece to a second solar cell piece in a manner such that the first solar cell piece and the second solar cell piece partially overlap. The first feature may be disposed in an overlap region of the first solar cell piece and the second solar cell piece.

[0082] According to a further embodiment, an apparatus for shaping an end portion of a conductive wire piece for a solar cell is provided. The apparatus includes a stamp for applying a pressing force to a portion of a conductive wire to separate the conductive wire into at least two conductive wire pieces including a first conductive wire piece. The stamp has a tapered contact surface for impacting the conductive wire to shape an end portion of the first conductive wire piece. The end portion tapers downwardly so that a height of the first conductive wire piece is reduced at the end portion. The apparatus may include any aspects, and any combinations of aspects, of the processing station 1900 described herein.

[0083] While the foregoing is directed to embodiments of the disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

Claims

1. A method of processing a substrate (210) used for the manufacture of a solar cell arrangement (1400), comprising: providing a substrate (10) having a conductive pattern (20) formed thereon; providing a current transportation wire (200) having a first height (310) at a bulk portion (210) of the current transportation wire and a second height (320) at an end portion (220) of the current transportation wire, the second height being smaller than the first height; attaching the current transportation wire to a first side (402) of the substrate in a manner such that the conductive pattern is electrically connected to the current transportation wire; providing a screen (610) over the substrate, the screen having an opening or set of openings (1010); and transferring a printing material from the screen to the substrate through the opening or set of openings to print a first feature (810) on the first side of the substrate next to the end portion of the current transportation wire.

2. The method of claim 1, wherein the first feature is disposed on the substrate within a distance (850) of 10 mm or less from the end portion of the current transportation wire.

3. The method of claim 1 or 2, wherein the first feature is at least one of an electrically conductive material and an adhesive.

4. The method of any of the preceding claims, further comprising: applying a downward pressure to the screen for transferring the printing material from the screen to the substrate through the opening or set of openings, wherein the opening or set of openings reach a vertical distance (750) from the substrate, the vertical distance being smaller than the first height of the current transportation wire at the bulk portion.

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5. The method of any of the preceding claims, wherein the end portion tapers downwardly so that a height of the current transportation wire gradually decreases at the end portion.

6. The method of any of the preceding claims, further comprising: providing a conductive wire (1950); and applying a pressing force to a portion of the conductive wire using a stamp (1920) to separate the conductive wire into at least two conductive wire pieces (2052, 2054) including a first conductive wire piece (2052), the stamp having a tapered contact surface (1922) for impacting the conductive wire to shape an end portion of the first conductive wire piece, wherein the first conductive wire piece is the current transportation wire or the current transportation wire is formed by further processing the first conductive wire piece, wherein the end portion of the first conductive wire piece is the end portion of the current transportation wire.

7. The method of any of the preceding claims, further comprising: separating the substrate into two or more solar cell pieces (1222, 1224, 1226) including a first solar cell piece (1222), the current transportation wire and the first feature being disposed on the first solar cell piece.

8. The method of claim 7, further comprising: bonding the first solar cell piece to a second solar cell piece (1420) in a manner such that the first solar cell piece and the second solar cell piece partially overlap.

9. The method of claim 8, wherein the first feature is disposed in an overlap region of the first solar cell piece and the second solar cell piece.

10. A method of processing a substrate used for the manufacture of a solar cell arrangement (1400), comprising: providing a substrate, wherein a conductive pattern (20) and a current transportation wire (200) are disposed on the substrate, the conductive pattern being electrically connected to the current transportation wire, the current transportation wire having a first height (310) at a bulk portion (210) of the current transportation wire and a second height (320) at an end portion (220) of the current transportation wire, the second height being smaller than the first height; and transferring a printing material from a screen (610) to the substrate to print a first feature (810) on the substrate next to the end portion of the current transportation wire.

11. A photovoltaic device, comprising: a substrate; a conductive pattern (20) disposed on the substrate; a current transportation wire (200) disposed on the substrate, the current transportation wire being connected to the conductive pattern, the current transportation wire having a first height (310) at a bulk portion (210) of the current transportation wire and a second height (320) at an end portion (220) of the current transportation wire, the second height being smaller than the first height; and a first feature (810) including a conductive paste disposed on the substrate next to the end portion of the current transportation wire.

12. An apparatus (2300) for processing a substrate used for the manufacture of a solar cell arrangement, comprising: a first processing station (2310) for attaching a current transportation wire to the substrate, the substrate having a conductive pattern formed thereon, the current transportation wire being attached to the substrate in a manner such that the conductive pattern is electrically connected to the current transportation wire, the current transportation wire having a first height at a bulk portion of the current transportation wire and a second height at an end portion of the current transportation wire, the second height being smaller than the first height; and a second processing station (2320) including a printer, the printer including a screen (610) having an opening or set of openings, the printer being configured to transfer a printing material from the screen to the substrate through the opening or set of openings to print a first feature on the substrate next to the end portion of the current transportation wire.

13. The apparatus of claim 12, wherein the printer further includes: a pressure application instrument (710); and an actuator (720) connected to the pressure application instrument, wherein the apparatus further includes a controller (730) connected to the actuator, the controller being configured to control the actuator to move the pressure application instrument downward to apply a pressure to the screen for transferring the printing material from the screen to the substrate through the opening or set of openings, such that the opening or set of openings reach a vertical distance (750) from the substrate, the vertical distance being smaller than the first height of the current transportation wire at the bulk portion.

14. The apparatus of claim 12 or 13, further comprising: a third processing station (1900) for forming the current transportation wire, the third processing station comprising a stamp (1920) for applying a pressing force to a portion of a conductive wire (1950) to separate the conductive wire into at least two conductive wire pieces (2052, 2054) including a first conductive wire piece (2052), the stamp having a tapered contact surface (1922) for impacting the conductive wire to shape an end portion of the first conductive wire piece.

15. The apparatus of any of claims 12 to 14, further comprising: 1 a cleaving station (2340) for separating the substrate into two or more solar cell pieces including a first solar cell piece, the first solar cell piece including the current transportation wire and the first feature.

16. An apparatus for shaping an end portion of a conductive wire piece for a solar cell, comprising: a stamp (1920) for applying a pressing force to a portion of a conductive wire to separate the conductive wire into at least two conductive wire pieces including a first conductive wire piece, the stamp having a tapered contact surface (1922) for impacting the conductive wire to shape an end portion of the first conductive wire piece, the end portion tapering downwardly so that a height of the first conductive wire piece is reduced at the end portion.

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