SE1930374A1 - Method to Interconnecting Strings of Solar Cells into Solar Cell Modules. - Google Patents

Abstract

The objective of the invention is to achieve a simplified interconnection of strings of solar cells in the making of solar cell modules. The solar cells in the strings are interconnected by the tape method. By the tape method are individual solar cells in a string interconnected by a continuous tape which carries tabbing wires. In the further building of the model the strings have to be interconnected. According to the invention is the tape method used to and integrate crossbars in a continuous process in the building of a module of interconnected strings. The form of the crossbars is such that the strings are connected in series when strings are placed side by side when building the module. The tape method enables a substantial reduction of cost of the process of interconnection of individual PV cells.

Description

1/15 Method to Interconnecting Strings of Solar Cells into Solar Cell ModulesField of the Invention The present invention relates to interconnecting strings of solar cells into solar cellmodules by integrating crossbars in the process of building strings of solar cells. These crossbars are thereafter used to interconnect the strings of solar cells in the module.

Background to the Invention The invention originates from the need to efficiently interconnect a number of solar cellstrings into solar cells modules. The solar cells are in the professíon called Photovoltaiccells (PV cells) and the solar cell modules are called PV modules. In the following textthe denominations "PV cells", "PV modu1es", "solar cells "or just "cells" and "modules"Will be used. The strings of solar cells to be connected comprise a number of cellsconnected in series. These strings are in the further manufacture of modules connected inseries. The process of manufacture of modules Will be described more in detail later.

The use of PV modules in the production of electricity is increasing. The cost of PVmodules has been reduced considerably during the last years. But still, the cost of the modules is high for the end user. Manufactures of modules are striving to reduce the cost of production of modules. Interconnection of cells into modules gives a considerable contribution to the cost of the module and new methods of interconnection are developed.

Interconnection is also called bonding. The electrically conducting Wires used Wheninterconnecting cells are called tabbing Wires. One proposed method for theinterconnection of cells is to use a tape carrying tabbing Wires. The tape and the tapemethod, as described in patent DE 19652810 A1, has several advantages in theproduction of modules and contributes to a reduction in cost. The patent SE 541365describes an improved tape to be used in the tape method. The tape and the tape method Will be described later. 2/15 The present invention concerns a method to efficiently interconnect strings of cells intomodules and the cells in the strings have been interconnected by the tape method. Theobjective of the invention is thus to utilize the tape method for interconnecting strings of solar cells.

A more detailed description is given in the following. The layout of the description is:- Description of a PV cell - Description of a PV module - Description of the bonding of PV cells into strings of PV cells by the tape method.

- Description of a method, according to the invention, to interconnect strings ofcells into a module. The cells in the string have been interconnected by the tapemethod. The tape is not only used in connection of cells but is, according to the invention, also used in the interconnecting strings of cells.

PV cell The PV cell comprises a number of thin layers on a supporting plate. The layers havedifferent functions which together results in a functional PV cell. There are a number ofdifferent types of PV cells, but the two main types are: thin film PV cells and silicon PVcells. In the following we will describe a silicon cell. The incoming radiation from thesun creates a voltage across the active layer in the PV cell and an electric current can betaken from the PV cell via electrical connections on the top- and backside of the PV cell.The topside and backside have different polarities. The topside is the side which receivesthe incoming solar radiation. The electrical connection on the topside is called topcontactand the connection on the backside is called backcontact. The topcontact is usually the negative electrode and the backcontact is usually the positive electrode.

Module A number of individual PV cells are electrical connected to each other to form a PV module. The PV cells in the module are interconnected in series in which the positive 3/15 electrode (usually the backside of the PV cell) is connected to the negative electrode ofthe PV cell (usually the topside of the cell) of a neighboring cell. ln the module a numberof cells are interconnected to a string of cells and the strings are placed close to eachother and the strings are interconnected in series. The connecting wires between the cellsin the string are called tabbing wires. The number of cells in the string may vary but atypical number is 10. The cell voltage of an individual cell is of about 0, 5 volts. Ten cellsinterconnected in series thus have a voltage of 5 volt. A number of strings describedabove are placed close and parallel to each other to form the module. The usual numberof strings in the module is 6. The distance between two strings is usually between 2 to 10mm but other distances may be used. The strings are interconnected in series and 6strings with 10 cells in each string give a module having a voltage of 30 volt and asurface area of 1, 6 m2. The description above describes a typical PV module but othermodes of interconnections and other numbers of PV cells in the module than thatdescribed above can be used. The laid out strings of PV cells in the module are supported,mechanically strengthened and sealed off from the environment by different sheets in the process of production. 4/15 Description of Tape Method In the tape method tabbing wires carried by a tape are used to interconnect cells. Thematerial in the tape is preferably a polymer, but other materials may be possible. Thetabbing Wires carried by the tape are interrupted at certain intervals in in a pattern thatenables an interconnection of the PV cells in series. With "interrupted" is here meant thatthe tabbing wire is cut with a gap between the ends in the cuts. The final interconnectionof the PV cells into a string of cells and closing of the electrical circuit is obtained in thelaminating step. The Tape Method (TM) is preferably suited to use there the individualPV cells have their negative and positive connections on the top- and backsides,respectively.

In the following we will describe a manufacturing method that can be used with the TM.The process starts with a first tape or a number of first tapes are placed in parallel on aprocess line, a conveyor belt. ln the ensuing text We Will use the singular word "tape" todescribe one or several tapes in parallel. The first tape carries tabbing wires as describedabove. The tabbing Wires carried by the first tape is facing upward. When a certain lengthof tape has been laid out, PV cell are placed on the tape. The cells can be placed with thetopside or the backside facing the tape. For simplifying the text, we will in the followingassume that the backside faces the first tape. All cells laid out will face in the samedirection. The backside faces the first tape with the tabbing wires and contacts the tabbingwires carried by the tape. The tabbing wires carried by the first tape consist of a materialthat can conduct current. The material in the tabbing wire is preferably solderable to thebackside of the cells. The first tape with tabbing wires is continuously laid out and cellsare placed after each other on the tape. Cells are laid out until the wanted number of cellsin a string is reached. The first tape facing the backside can also have an adhesive appliedon the tape. The adhesive is to ensure a good fixing of the tape to the PV cell. Thetabbing wires have, as noted earlier, at regular intervals been cut with a distance betweencuts which is of the same order as the width of the PV cell. The cut of the tabbing wire is made with a small distance between cuts. /15 Now we return to the building of a module. The desired number of cells in a string(usually 10) is placed on the conveyor belt with the first tape and the backside of the cellsfaces the tape with tabbing wires. The cells in the string are separated with a smalldistance, a free space, between the cells and a part of the tabbing wire extends over thisfree space. That is, a part of the tabbing wire is not covered by the cell and this free partof the tabbing wire extends over said free space between two cells. The building of thestring continues and a second tape with tabbing wires is placed on top of the above laidout string of cells. The tabbing wires in the second tape are now resting on and contactthe topsides of the cells. The material in the tabbing wires on the second tape canpreferably be solderable to the material in the topcontact of the cells. The second tapewith tabbing wires have the same design as the former described first tape which is usedon the backside of the cell. The second tape with tabbing wires on the topside of the cellshave a part of the tabbing wire that extends over the free space between two cells. Wenow have tabbing wires on the topside and on the backside of the cells and that a part ofthe tabbing wire on the two sides of a cell overlaps in the free space between two cells. Itis these overlapping tabbing wires that contact each other in the process of laminationthus forming the contact in series between the positive and negative electrodes of twoadjacent cells. The process above is now repeated to build more strings until the wantednumber of strings obtained.

In the further building of the module, the strings are placed with topside down on a firstsealing sheet which in turn rests on a topglas. When the desired number of strings hasbeen placed the strings are interconnected in series with separate connectors. Thebuilding of the module continues with a sealing sheet that covers the strings in the module. Finally, a backsheet is placed on top.

The complete module with topglas, first sealing sheet, strings of cells withinterconnecting tabbing wires, second sealing sheet and backsheet is placed on a heated(150 ° C) plate in a laminator chamber. The chamber is closed and evacuated to vacuum.The vacuum chamber has a rubber membrane in the lid at the inside of the vacuumchamber. At start of the lamination process the membrane is sucked up against the lid by the vacuum. When the chamber is evacuated to the wanted vacuum level the space 6/15 between the lid and the membrane is opened to the ambient air and the membrane Will,due to the vacuum in the chamber, push the module against the heated lower part of thechamber. This "push" will be exerted on the module for about 10 minutes. The push andthe heat will soften and melt the sealing sheets and fix the module to a robust unit. Thevacuum in the chamber is vented, the chamber is opened, and the finished module isremoved from the chamber.

The earlier described push from the outside and the vacuum on the inside will bring thefree tabbing wires in the space between the cells in contact with each outer. We shall alsonote the distance between two cells is usually between 2 to 10 mm and the thickness of acell is of about 0, 2 mm. That is, the free tabbing wires only have to be pushed 0,2 mm toget in contact. During the pushing and heating the tabbing wires also contact the topsideand the backside of the PV cells.

Preferably, can the tabbing wires be furnished with a solder that melts and solders at thelamination temperature and thus the tabbing wires are soldered to each other, to thetopcontact on topside the backcontact on the backside. Once again, we note that theoutside push and the vacuum have brought the free parts of the tabbing wire in the space between PV cells in contact with each other.

Above it is described how a tape with having tabbing wires intenupted at certain intervalsis used. But it is also possible to cut the wires after a tape with continuous wire being placed on the cells as described in the patents SE 1430133.

Tape method and integration connectors for connecting strings of cells The tape method is well suited for the adaption into a continuous process in which,according to the invention, crossbars for interconnecting strings of cells can be integratedin the building of string of cells. Crossbars are strips of conductive material thatinterconnects strings of solar cells in the module. The integration of crossbars in the tapemethod simplifies the production of modules. The process with the integration of crossbars is described in the following steps.

Step 1: 7/15 The process starts with a first tape carrying tabbing wires being continuously laid out on aconveyor belt. Several tapes can be laid out in parallel. The number of parallel tapes with tabbing wires can vary but the trend is towards an increasing number of tabbing wires for the interconnecting of cells. A common number today is 5. Even larger numbers may be used.

Step 2: Cells are thereafter placed on the first tape on the conveyor belt. The cells are preferablyplaced with the backside of the cell facing the first tape with the tabbing wires. For clarityit is noted that the tabbing wires on the first tape faces and meet the backside of the cell.It is also possible to place the topside of the cell to face the first tape with the tabbing wires.

Step 3 A second tape with tabbing wires is laid out on the topside of the cells already laid out. Inthis manner a string of solar cells is obtained in a continuous process. The cells, first andsecond tape are placed in such position that the cells can be interconnected in series bythe tabbing wires carried by the tapes. This is earlier described in the section describing the tape method Step 4: A very long string of cells ready for interconnection can now be made. But when buildinga module, the practical number of cells in a string in a module is limited. Usually thewanted number of cells in a string is 10. Therefore, according to the invention, is theplacing of cells interrupted after a certain number of cells and a gap between two stringsof cells is formed. The size of the gap is the size of a cell. The gap has not yet beencovered by the second tape. Now two crossbars are placed in the gap. One crossbar isplaced close to the last cell in the string laid out. The other crossbar is positioned close tofirst cell in next string to be built. The crossbars have preferably been coated with asolder that enables soldering to the tabbing wires in the first and second string and soldering to another crossbar when interconnection between strings is established. 8/15 Step 5: The second tape which is continuously laid out over the cells is also laid out over the gapbetween cells. This a gap has the size of a cell which is of about 150 mm. The secondtape passes over the gap and thus also over the two crossbars in the gap. The crossbarsare now held in place by the first and second tape. This holding is further facilitated if thefirst and second tape is furnished with adhesives on the tape sides that face the cell. Thelength of the crossbar is chosen in such a manner that an interconnection in series of thestrings of cells can be obtained when the strings are laid out side by side to form a module.

Step 6The conveyor belt is preferably moving at a fixed speed in continuous motion. The tapein the gap is thereafter cut in a continuous motion between the above described two crossbars. By this cutting separate strings of cells is formed.

Step 7 In step 7 separate strings are placed side by side with a small distance between thestrings. The strings are preferably placed on a sealing sheet that rest on a topglass. Theplacing of the strings is such that the crossbars contact each other and form an interconnection in series between the strings.

The final interconnection of strings is established in the lamination.

Summary of the Invention The objective of the invention is to achieve a simplified interconnection of strings ofsolar cells in the making of solar cell modules. According to the invention is the tapemethod adapted to in a continuous process integrate crossbars in the building of strings of interconnected cells. The tape method enables a substantial reduction of cost of the 9/15 process of interconnection of individual PV cells. The tape method is further improved bythe invention. According to the presented invention the improved tape method ischaracterized of features of claim 1 in Which crossbars for interconnecting strings of cellsare integrated in the continuous process of interconnecting individual solar cells With a tape into strings of solar cells.

The invention also relates to a method according to claim 2 in Which the interconnection of strings via the crossbars is obtained in the lamination step.

The invention also relates to a method according to claim 3 in Which the crossbars is positioned in a vacant cell position.

The invention also relates to a method according to claim 4 in Which the tape on the side that faces the backside of cells has an adhesive on the side that faces the backside.

The invention also relates to a method according to claim 5 in Which the tape on the side that faces the topside of cells has an adhesive on the side that faces the topside.

The invention also relates to a method according to claim 6 in Which the tape on the sidesthat faces the top- and backside side of cells have an adhesive on the side that faces the top- and backsides.

The invention also relates to a method according to claim 7 in Which the interconnecting crossbars carries bypass diodes.

The invention also relates to a method according to claim 8 in Which strings of cells areseparated by cutting the tapes laid out are When the strings of cells is in a continuous motion.

The invention also relates to a method according to claim 9 in Which the first laid out tape is held in place on the conveyor belt by a vacuum system. /15 Brief Description of the Drawings Figure l shows a Photovoltaic Cell (PV cell) With an active layer, a topcontact, and a backcontact.

Figure 2 shows the interconnection in series between the topcontact and backcontact of PV cells.

Figure 3 shows a typical assembly of cells in a module Figure 4 shows a schematic of a string of cells to be connected in series by the tapemethod. The figure shows the string before lamination with the tapes laid out on both sides of the cells.

Figure 5 shows a side view of a module assembled with the tape method before lamination.

Figure 6 shows a module assembled by the tape method after lamination.

Figure 7 shows a line to produce strings of PV cells with the tape method and with integrated crossbars.

Figure 8 describes the sequence when laying out crossbars in a gap between two solar cells.

Figure 9 shows a top view of strings of cells with crossbars.

Figure 10 shows strings in a module are connected in series with crossbars. 11/15 Figure ll shows a possible position of bypass diodes carried by crossbars.

Detailed Description of Preferred Embodiments Figure l shows a PV cell l having an active layer 2, a topcontact 3 and a backcontact 4.Topside 6 receives incoming solar radiation 5. The solar radiation is schematically shownwith arrows. Figure 1 also defines a backside 7 of the PV cell. The incoming solarradiation 5 generates a voltage in the active layer. The voltage sets up a current which isled from the PV cell via the topcontact 3 and the backcontact 4. The topcontact is usuallythe negative electrode and the backcontact is usually the positive electrode. Figure 1shows a PV cells having the topcontact and the backcontact on the two sides of the PVcell. There are also PV cells in which the topcontact 3 has been led down to the backside 7 of the PV cell. This is not shown in a figure.

Figure 2 shows how PV cells 1 are interconnected in series via tabbing wires 21 whichextends from an electrode 23 having positive polarity (plus electrode) to an electrode 22having negative polarity (minus electrode). Figure 2 shows a PV cell having electrodes on each side of the PV cell.

Figure 3 shows a common layout of PV cells in a module. Strings 31a, b, c, d, e, f with 10PV cells lconnected in series are placed close to each other. Six strings are laid out. Thestrings are interconnected in series with crossbars 33. Exit terrninals 34, 35 having different polarities exit the current from the module.

Figure 4 shows a string of PV cells be interconnected by the tape method. The figureshows cells and tapes before lamination. A continuous tape 41 carrying tabbing wires 42is positioned on the side of the cell 1 facing down. A continuous tape 43 carrying tabbing wires 44 is placed on topside of the cells. The tabbing wires 42, 44 are cut in such a 12/15 manner that the PV cells are interconnected in series in a space 45 after lamination. Thesize of the cell is of about 150 mm and the size, distance between cells, of the space 55 is of about 2 to 5 mm.

Figure 5 shows a side view of an assembled module before lamination. The tape 41 withthe tabbing wires 42 faces the backcontact of the cells 1. The tape 43 with the tabbingwire 44 faces the topcontact of the cells 1. The figure 5 further shows show a topglass 51,a first transparent sealing sheet 52. The sealing sheet 52 is usually made of a polymermaterial called EVA (Ethylene Vinyl Acetate). Solar radiation passes through thetopglass 51 and the sealing sheet 52. On the backside of the PV cells there is a secondsealing sheet 56. The assembly of the module is finished with a backsheet 57. After thisthe module is baked in a larninator. The laminator is not shown with a figure. Figure 5only shows a part of a string in a complete module. A complete module usually has 6strings with ten PV cells in each string. For clarity it shall be pointed out that figure 5shows the module with distorted scales. The actual PV cell 1 has in reality a thickness ofabout 0, 2 mm and the length of the cell is 150 mm. The distance, the space 45, between two adjacent cells is of about 2 to 10 mm.

Figure 6 shows a module 60 after lamination with PV cells 1 interconnected by tabbingwires 42, 44 which are carried by the tapes 41, 43. Tabbing wire 42 contacts the cell sidefacing down and the tabbing wire 44 contacts the cell side facing up. Figure 6 shows themodule after larnination and the tabbing wires 42, 44 are now brought in contact witheach other in the space 45 and a contact in series between individual PV cells has beenobtained. The sealing sheets 52, 56 have softened, melted, and filled the space 45between the PV cells. The melted sealing sheet is indicated with pointers 61, 62. In thefigure 6 the tape 41, 43 have merged with the melted sealing sheet and are thus not seen in figure 6 Figure 7 shows a schematic of a production line used in the tape method and the laying out of crossbars 76a, 76b. A first tape 77 taken from spool 78 is continuously laid out on 13/15 a conveyor belt 71. The first tape 77 carries the tabbing wires 42. The tape 77 can be heldin place on the conveyor belt with a vacuum system in the conveyor belt. The vacuumsystem is not shown in the figure. Cells 1 are placed on the conveyor belt 71 and on thetape 77. The cells are preferably placed with the backside of the cells facing down. Thetabbing wires 42 carried by the tape 77 contacts the backside of the cells. The backside ofthe cell is the side of the cell which don"t receives any solar radiation. The direction ofmovement of the conveyor belt is shown with arrow 72. The cells 1 are placed on theconveyor belt at a position 73 with a "pick and place" robot. The pick and place robot isnot shown in the figure. In the production line shown in figure 7 strings 74 with two solarcells in each string are built. Between each set of two cells there is a gap 75. In the gap 75the crossbars 76a and 76b are placed. A second tape 79 taken from the spool 701 iscontinuously placed on the topside of the cells and also over the gap 75. The second tapecarries the tabbing wires 44. The string with cells, first tape, second tape and crossbars isdelivered to a pickup station 702. The pickup station can be stationary or being a secondconveyor belt. Further downstream the production line there is a cutting station forcutting the first 77 and second tape 79 between the crossbars 76a, 76b. The cutting system is not shown with a figure.

Figure 8 shows in detail the sequences when laying out the crossbars 76a, 76b.Figure Sa shows two cells 1 and the gap 75 between the two cells. The two cells are here shown placed on the first tape 77 with the tabbing wires 42.

Figure 8b shows the positions of crossbar 76a, 76b. Here it can be noted that the figureshows the assembly with distorted scales. The actual thickness of a real solar cell is 0,2 mm and the size width of the gap is 150 mm. The width of the crossbar is of about 4 mm.

Figure 8c shows the position of the second tape 79 with the tabbing wires 44 which are placed on top of the cells 1 and over the gap 75. 14/15 Figure 8d show cuts 82a, 82b after cutting the tapes 77, 79 and the tabbing wires 42, 44.The position of the cuts 82a, 82b may vary but the cuts are preferably made close to thecrossbars 76a, 76b.

In the lamination a contact between the crossbar 76a and the topside of the cell isobtained via the tabbing wire 44 and the crossbar 76b contacts the backside of the cell via the tabbing wire 54.

Figure 9 shows 4 strings 91a, 91b, 91c, and 91d of cells 1 with two cells in each string.The strings have been built in a continuous process as described in figure 7. The stringshave on the two sides of the string crossbars 76a, 76b. The crossbar 76a is connected tothe topside 6 of the first cell in the string 91a via the tabbing wire 54 which is carried bythe tape 79. The crossbar 76b is connected to the backside of the cell via the tabbing wire52 which is carried by the tape 77. The crossbar 76a is thus connected to the negativeterminal of the string and the crossbar 76b is thus connected to the positive terminal ofthe string. Depending of type of cells or cell position the polarities may be reversed. Butstill, the crossbars 76a, 76b are connected to different polarities. Strings 91b, 91c, 91c areconnected to crossbars in the same manner. The crossbar 76a connected to the negativeterminal 95 of the string 91a has a part 92 that extends in the direction of the crossbar 76aand mainly in a direction perpendicular to the string. The crossbar 76b connected to thepositive terminal 96 of the string 91a has a part 93 that extends in the direction of thecrossbar 76b and mainly in a direction perpendicular to the string direction.

Crossbar 76c connected to the negative terminal 95 of the string 91b have parts of thecrossbars extending in different direction from that showed for the crossbar 76a whichconnects to string 91a.

Crossbars 76d connected to the positive tenninal 96 of the string 91b have parts of thecrossbars extending in different direction from that showed for the crossbar 76b whichconnects to string 91a.

String 91c has crossbars extending in direction that differ from the directions shown instring 91b. And again, string 91d has crossbars extending in direction that differ from the directions shown in string 91c. /15 Figure 10 show a module 100 with the strings 91a, 91b, 91c, 91d laid side by side to forma module. The strings are laid out in a manner that interconnects the crossbars with thepositive and negative terminals of the strings. The connection points are indicated withthe pointers 101. The current from the module is drawn from the module via terminals102, 103. The terminal 102 is the negative tenninal and the 103 is the positive terminal.The polarities may be reversed depending of type of cells or cell position. The figure 10shows a module with four strings having two solar cells in each string. This gives amodule having voltage of 4 volts if each cell has a voltage of 0,5 volts. A fully builtmodule usually has 6 strings with 10 cells in each string. This gives a module having a voltage of 30 volts.

Figure 11 shows how the crossbars 76a, 76b can be furnished with bypass diodes 111 and112. The bypass diodes are integrated in the crossbars and gives a bypass connection viadiodes 111 and 112. The purpose of the diodes is to bypass faulty or shaded strings. Inmodule in figure 11 with four strings two diodes are used. Other positions of the diode may be possible.

Claims (2)

1. 1. /2 Claims 1 Metod att elektriskt sammanbinda strängar (31) av solceller (1) i byggande av ensolcellsmodul (30). Solcellerna i strängama är elektrisk sammankopplade med kontinuerligataper (41, 43, 77, 79) vilka bär elektriskt ledande trådar (42, 44) och att trådarna som bärs avtaperna är avklippta med intervall som medför att nar taperna placeras på en strängs toppsida(6) och baksida (7) erhålles en elektrisk sammanbindning i serie av celler och därmed formasen kontinuerlig sträng av solceller kännetecknad av att tvärstycken (76a, 76b) försammankoppling strängar av solceller (31, 74) positioneras i ett gap (75) i kontinuerligtbyggda strängar (74) av solceller och att tvärstyckena positioneras på ett sådant satt att enpositive (96) och en negative (95) pol i två närliggande strängar kontaktar varandra när strängarna läggs sida vid sida vid byggande en modulen (30, 100). 2Metod enligt krav 1 kännetecknad av att den slutliga sammanbindningen av strängar (31) erhålles i lamineringssteget. 3Metod enligt något av kraven 1 och 2 kännetecknad av att gapet (75) i strängen (74) av solceller formas av vakant solcellsplats. 4Metod enligt något av kraven 1, 2, och 3 kännetecknad av att den först utlagda tapen (77) har ett häftämne på den sidan som möter mot cellerna i strängen (74). 5Metod enligt något av kraven 1, 2, och 3 kännetecknad av att den andra utlagda tapen (79) har ett häftämne på den sidan som möter mot cellerna i strängen (74).

2. /2 6 Metod enligt något av kraven l, 2, och 3 kännetecknad av att den först utlagda tapen (77) andra utlagda tapen (79) har ett haftamne på de sidor som möter mot cellerna i strängen (74). 7 Metod enligt något av kraven l, 2, 3, 4, 5 och 6 kännetecknad av att de sammankopplandetvarstyckena (76a, 76b) bar förbikopplingsdioder (lll, ll2) vilka förbikopplar felandesträngar. 8 Metod enligt något av kraven l, 2, 3, 4, 5, 6 och 7 kännetecknad av att klipp (82a, 82b) somklipper den först utlagda tapen (77) och den andra utlagda tapen (79) görs nar strangama av solceller befinner sig i en kontinuerlig rörelse 9Metod enligt något av kraven l, 2, 3, 4, 5, 6, 7 och 8 kännetecknad av att den först utlagdatapen (77) på ett transportband (7l) hålls på plats på transportbandet (77) med ett vacuumsystem.