EP2449602A2

EP2449602A2 - Method for exposing an electrical contact

Info

Publication number: EP2449602A2
Application number: EP10726125A
Authority: EP
Inventors: Axel Heinrici; Günter Neumann; Lars-Soeren Ott
Original assignee: Reis Group Holding GmbH and Co KG
Current assignee: Reis Group Holding GmbH and Co KG
Priority date: 2009-06-29
Filing date: 2010-06-29
Publication date: 2012-05-09
Also published as: WO2011000814A2; WO2011000814A3; US20120228275A1

Abstract

The invention relates to a method for exposing at least one electrical contact, which is covered by at least one layer made of plastic, by means of a laser beam. In order to allow the targeted and reproducible exposing of the electrical contact in an automated process, the location of the at least one electrical contact is determined by means of a sensor, and the at least one layer made of plastic is removed in a flat area, in consideration of the determined location of the electrical contact and according to a pattern stored in a controller of a laser scanner, the projection of said flat area being inside of the contact in the direction of the contact.

Description

Method for exposing an electrical contact

The invention relates to a method for exposing at least one electrical contact of a solar cell or a solar cell module covered by at least one layer, preferably made of plastic.

DE-B-199 64 443 discloses a device for removing layers on a workpiece by means of a laser beam, which has a trapezoidal beam profile on the surface to be machined. Also suitable as a workpiece are thin-film solar cells in which layers lying over the contact surface of the backside electrode are selectively removed. As a laser, a pulsed laser of the type Nd: YAG is used, which is operated by the method of quality modulation with pulse durations in the range of 25 μ s.

From DE-A-10 2007 011 749 a method for producing a solar cell is known in which a transparent dielectric layer is removed locally by means of an ultrasound short pulse laser.

In order to produce an opening in a polymer layer consisting of a dielectric layer for exposing an electrical contact, a laser radiation is used according to EP-AO 388 009. From US-A-5,480,812 (EP-B-0 685 113) a method for repairing a line of a thin-film image sensor is known. In this case, a non-conductive layer in the repair area can be removed by means of a laser.

The subject of EP-A-0 649 045 is a method for repairing interruptions of a liquid crystal substrate. For this purpose, a medium is applied to the interrupted area and melted by laser to repair the connection.

To surfaces of z. B. workpieces, takes place according to DE-A-199 00 910 a removal of the surfaces by means of a laser radiation.

JP-A-2004 066 344 discloses a device for observing areas which are repaired by means of laser radiation.

In order to remove burrs on housing sides so that electronic components are exposed, DE-A-103 13 521 provides that the burrs are removed by means of laser radiation. The corresponding areas are detected by an image recognition and processing system.

By means of a CO ₂ laser holes are formed according to EP-A-0 884 128 in a plastic layer to allow connections to a printed circuit.

In the production of photovoltaic modules, it is necessary in the prior art to unthread the interconnection or cross-bonding interconnects prior to laminating the modules from the backside covering transparent plastic layer, which may be ethylene vinyl acetate (EVA) or silicone rubber Ribbon to connect with the terminals of a contact box. The required recesses in the plastic layer and this back covering plastic composite film z. B. of polyvinyl fluoride and polyester to be Example formed by punching. However, for the unthreading of the cross connector an additional, usually manual intervention before lamination is required.

Faulty electrical connections not only cause the efficiency of the modules is deteriorated, but there is a risk due to so-called hot spots that heat generation that can trigger a fire.

If it is determined during production that a proper interconnection between the individual strings of the module has not occurred, then this will be retired.

The present invention is u. a. the object of developing a method of the type mentioned in such a way that in an automated workflow, a targeted and reproducible exposure of an electrical contact is made possible to allow in particular in subsequent processing a desired electrically conductive connection to terminals. At the same time it should be ensured that when exposing the electrical contact damage to the contact otherwise surrounding material is avoided. In accordance with a further aspect, a plurality of electrical contacts covered by at least one layer made of plastic are to be exposed in defined areas in order to simultaneously be able to automatically connect them to further contacts. In particular, the possibility should be created to connect a solar cell module in an automated workflow with a junction box.

It is also an aspect of the invention that with simple measures a repair of faulty electrical contacts is made possible, so that in particular faulty solar cell modules can be reused or reused.

To solve the problem or aspects, the invention essentially provides

Determining the position of the at least one contact by means of a sensor, removing the at least one layer by means of a laser beam of a laser scanner, taking into account the determined position and a stored in a control of the laser scanner pattern wherein the at least one layer is removed in a flat area, the projection of which lies in the direction of the contact within or substantially within it.

The removal of the layer in a region whose projection lies in the direction of the contact within it means that the region of the layer immediately adjacent to the contact lies within or essentially within the projection in the direction of the contact. In the surface region of the layer to be removed, however, it is possible to remove a region which is also located outside the projection in the direction of the contact, so that the result is a funnel-shaped exposure. This is advantageous for the contact to be made or in the event that a contact is to be repaired.

The feature "essentially within the contact" is intended to express that the invention will not be abandoned even if layer material is removed in the immediate area of the contact, which is present laterally next to the contact used laser radiation is not coupled into the glass, which extends over the solar cells to be interconnected and light radiation entrance side.

Thus, the invention is also distinguished in particular by the fact that, starting from the surface of the at least one layer to be removed, material is removed in the direction of the contact such that a funnel-shaped opening results in the at least one layer, whereby projection of the opening in the region of the surface in FIG Area of the contact outside of this region and projection of the contact abutting opening is located within or substantially within the contact.

However, the invention also includes, in particular, that the laser beam directly above the contact removes a region of the layer whose projection lies in the direction of the contact exclusively within the contact. In particular, it is provided that a plurality of electrical contacts in the form of cross connectors of a laminated solar cell module are exposed and connected to contacts of a junction box, the cross connector solar cell module back side are covered by a transparent plastic layer and a plastic film and the plastic layer and the plastic film are removed by means of the laser beam.

Furthermore, the invention provides that the electrical contact is a faulty contact, which is repaired or renewed after the removal of the at least one layer.

To solve one aspect of the invention, it is thus proposed that the position of the at least one electrical contact is determined by means of a sensor and that taking into account the determined position of the electrical contact corresponding to a stored in a control of a laser scanner pattern, the at least one layer of plastic in one flat area is removed, the projection is in the direction of the contact within this.

To solve the object of a further aspect, essentially the method steps are proposed:

Determining the position of the contact to be repaired by means of a sensor, removing the at least one layer by means of a laser beam of a laser scanner, taking into account the determined position and a stored in a control of the laser scanner pattern, and

Repair or renew the electrical contact.

According to the invention, a method of laser-based removal of at least one plastic layer is proposed, wherein an automation is provided which leads to reproducible results and at the same time ensures that the at least one electrical contact is exposed exclusively in the region in which one contact with another Contact should be made. For interconnecting solar cell modules in which contacts are to be exposed, the cross-linking tapes are exposed only after lamination, whereby the films are not partially opened before lamination and threaded through this the Querverschaltungsbänder. This prevents liquefied EVA material from leaking out of the open area, contaminating and damaging the laminator membrane.

In particular, an optical sensor with image processing is used as the sensor, so that the data determined by the transmitted light method transmits the position of the at least one electrical contact to the controller of the laser scanner and this or the areas in the electrical contact according to the pattern stored in the controller can expose. It can be used as a laser scanner such with a two-axis scanning system with preferably planar field optics or a three-axis scanning system with fixed focal length.

Pattern here means or includes how the laser beam is moved to the contact to be exposed or repaired. However, the pattern may also include laser power, the width of the laser beam incident on the ablated layer, or other parameters required for the application of the laser radiation.

Due to the absorption and transmission properties of the film materials used, a CC laser system is preferably used. This can be either a cw laser used or a pulsed laser system. In the latter case, it is preferable to operate with a pulse frequency greater than 5 kHz, in particular greater than 10 kHz, so that a quasi-continuous operation results.

The maximum process speed depends directly on the laser power. In order to remove the at least one layer made of plastic, the laser beam should extend over the region to be removed at a speed between 200 mm / sec and 7500 mm / sec, in particular between 2000 mm / sec and 4000 mm / sec, preferably between 3300 mm / sec and 3700 mm / sec, to be moved. For a beam source of 300 W, a favorable range is in particular between 3300 mm / sec and 4500 mm / sec. At very high available laser powers, however, higher process speeds can also be realized

The direction of movement of the laser beam itself can be arbitrary. Preferably, however, a meandering or zigzag-shaped movement can be performed. This results in the advantage that the areas are applied uniformly with the laser beam, so that unwanted heat generation are excluded, which could lead to damage.

Regardless of this, the energy of the laser beam should be adjusted so that the area to be removed several times, in particular two to five times traversed, whereby a particularly gentle sublimation, ie evaporation of the existing plastic layer takes place without damaging the electrical contact or to given these running areas.

A reproducible removal results even when the laser beam along parallel lines over the surface to be removed is moved, wherein the distance between the lines should be smaller than the imaged onto the surface focus diameter of the laser beam.

If a movement takes place in such a way that a reversal of motion takes place in the edge region with simultaneous stopping of the laser beam-guiding mirror of the laser scanner, then the laser is switched off at the point of reversal so that unwanted heat generation is avoided. Brake / acceleration effects of the mirrors of the laser scanner are not noticeable in this case, so that a uniform, ie homogeneous removal is ensured.

The laser beam itself should be imaged punctiform on the surface to be ablated with a diameter of between 0.3 mm and 1.2 mm, in particular between see 0.4 mm and 0.8 mm. If a smaller focus is used, a higher process speed can be achieved.

In order to achieve an economic removal rate, the laser should be operated at least with a power P of 100 watts <P <1000 watts. Higher powers are possible and allow higher process speeds, but require significantly higher investment costs.

The optical sensor for image processing for detecting the position of the electrical contact should run with respect to the laser scanner on the opposite side, which can be measured by transmitted light method.

In particular, the invention is characterized by a method for exposing to be connected to contact a junction box cross connectors of a laminated solar cell module, the cross connector solar cell module back side of a transparent plastic layer of ethylene vinyl acetate (EVA) or silicone rubber and a plastic film are covered, preferably polyvinyl and polyester contains.

The inventive method is not only suitable for exposing contacts to connect them with contacts of a junction box. The uncovering of at least one cell or string connector to be connected cross-connector of a laminated solar cell module is possible due to the teaching of the invention.

It has been found that the method according to the invention is extremely suitable for exposing areas of electrical contacts, such as cross connectors of photovoltaic modules, in a laser-based manner, ie, for example. B. subsequently introduce recesses after lamination, then to allow automatic connection with external contacts such as the contacts of a junction box or to repair or renew faulty contacts. In this case, an automation is carried out such that by means of z. B. an image processing or other suitable sensor detects the position of the electrical contacts, the position data supplied to the control of a laser scanner and then in Depending on a stored pattern of the laser beam is passed over the electrical contacts, so that the covering these layers are removed by evaporation.

In this case, the laser beam can be controlled in such a way that exclusively or essentially exclusively areas above the electrical contact are exposed, so that damage to further areas and, in particular, an energy input outside the electrical contact can not take place to an extent that could lead to the the solar cell module on the front side covering glass jumps.

In particular, it is provided that the or the exposed areas are adhesively bonded by means of soldering, such as laser, induction or contact soldering.

In the case of exposing cross connectors to connect them with contacts of a junction box is provided in a further that after exposing the cross connector, the solar cell module is fed to a processing station, placed in the means of a handling device on the exposed areas of the cross connector, the contacts of the junction box and these are then positively and / or materially connected to the exposed areas. The processing station can also be the one in which the contacts are exposed.

In particular, it is provided that the exposed areas are connected conclusively by means of soldering, such as laser, induction or contact soldering material.

During the electrically conductive connection of the exposed areas with the contacts or thereafter, the junction box is then connected to the solar cell module, preferably by means of silicone or adhesive tape.

In order to align the contacts of the junction box with exact position on the exposed areas of the cross connector, it is provided that the position of the solar cell module with the exposed areas detected by means of image processing and thus obtained data control of the handling device. Thus, one is perfect electrical contact ensured. The position detection can be omitted if the exposure of the cross connector and setting the junction box in the same processing station done.

For more details, advantages and features of the invention will become apparent not only from the claims, the features to be taken these features - alone and / or in combination, but also from the following description of the drawing to be taken preferred embodiments.

Show it:

1 is a schematic representation of an arrangement for removing a plastic layer covering an electrical contact,

2 shows a detail "A" of Fig. 1,

3 shows a detail of a solar cell module,

4 shows a detail "A" of FIG. 3,

Fig. 5 is a schematic diagram of an interconnection of cross connectors of a

Solar cell module with contacts of a junction box,

6 shows the arrangement according to FIG. 5 in a side view, FIG.

7 shows a first embodiment of a contact of a junction box with a cross connector,

8 shows a second embodiment of a contact of a junction box with a cross connector, 9 is a schematic representation of another arrangement for removing a plastic layer covering an electrical contact and

10 shows a detail "A" of FIG. 9.

In FIGS. 1 to 8, the teaching according to the invention for exposing at least one electrically conductive contact, which is covered by at least one layer consisting of plastic, is described on the basis of a solar cell module without the teaching of the invention being restricted thereby. In this case, the same reference numerals are used in the figures for the same elements in principle.

In Fig. 1, an arrangement is shown purely in principle, with a cross connector 10 of a solar cell module 12 is exposed, then to be electrically connected to terminal contacts of a contact socket.

For this purpose, a laser scanner 14 is provided which, in addition to a laser emitting laser such as CO ₂ laser deflection mirror and optics to move the laser beam 16 over a desired region of the solar cell module 12 to remove the cross connector 10 covering layers 18, 20 by evaporation , It is a laser scanner used, the structure and operation of which are well known to one of ordinary skill in the art.

According to the embodiment of the solar cell module 12 is in the layers 18, 20 to a transverse connector side extending transparent plastic layer of z. For example, ethylene vinyl acetate (EVA) or silicone rubber and these outside covering weatherproof plastic composite film of particular polyvinyl fluoride and polyester.

In the region of the cross connector 10 extends below this another transparent plastic layer of z. B. ethylene vinyl acetate or silicone rubber, which is indicated at 22. The corresponding unit is on a glass plate 24 or another arranged transparent carrier. The interconnected solar cells themselves are not shown, which are located between the layers 20 and 22.

After arranging the individual layers and the solar cells, the lamination of the module takes place in particular at temperatures of about 150 ^° C. and under reduced pressure. During lamination, the initially milky transparent plastic layers (EVA or silicone rubber) immediately surrounding the solar cell form a clear plastic layer, in which the solar cells are embedded and fixedly connected to the glass pane or backsheet. In that regard, however, reference is made to well-known techniques.

In order to connect the cross connector 10 with the terminal contacts of a junction box, the laser beam 16 is moved in the areas 26 to be exposed according to a predetermined pattern, which is stored in the control of the laser scanner 14. In this case, an energy input takes place to such an extent that the layers 18, 20 extending above the cross connector 10 evaporate without any damage to the environment, that is to say of the adjacent region of the solar cell module 12. In particular, it is avoided that the laser beam 16 adjacent to the cross connector 26 impinges on the layers 18, 20 in an amount that can be coupled into the glass plate 24 with the consequence that it bursts.

The movement of the laser beam 16 can take place in a meandering or zigzag-shaped or linear manner along parallel straight lines. However, it is essential that a uniform removal, ie a uniform evaporation of the layers 18, 20 above the cross connector 26 takes place. Therefore, in the event that the or the mirror of the laser scanner 14 are stopped, a turn-on delay for the laser is provided.

This means that at standstill of the mirror or laser light does not hit the module, so the laser is turned off. The distance of the laser lines can be varied, whereby an overlap of the laser lines takes place. In particular, the laser can be moved over the area to be removed such that the distance between the laser lines is in the range between 0.05 mm and 0.2 mm, preferably in the range between 0.1 mm and 0.2 mm. Thus, a sufficient overlap is given because the diameter of the focus is greater than 0.1 mm, in particular in the range between 0.4 mm and 1.0 mm.

The laser system preferably has a CO ₂ laser with a two-axis scanning system. In order to image the focus in a straight plane over the entire surface to be removed, a corresponding planar field optics is provided. However, it can also find a three-axis scanning system with fixed focal length use.

Irrespective of this, the CO ₂ laser should work with a maximum duty cycle of 50%, the pulse widths should be between 10 μ / sec and 400 μ / sec.

The speed with which the laser beam travels over the area to be removed should be in the range between 1000 mm / sec and 4000 mm / sec, with particularly uniform results being achievable if the area to be removed is run over several times by the laser beam. Speed, laser power and pulse frequency should therefore be tuned in such a way that it is possible to drive over it two to three times. More preferably, a quasi-continuous operation should be set, so that pulse frequencies of more than 10 kHz are to be preferred.

Furthermore, it is provided that the surface removal rate between 75 mm ² / sec and 225 mm ² / sec with a thickness of the layers 18, 20 to be removed is between 0.5 mm and 1 mm.

5 and 6 are intended to illustrate that corresponding according to the invention exposed cross-connector 10 of the solar cell module 12 are then contacted with connection contacts 28 of a junction box 30, in turn, with the solar cell module, ie, the laminate z. B. is connected with silicone or tape. This should be pure are illustrated in principle by the marked with the reference numeral 32 border in Fig. 6.

Previously, by means of an image processing system or other sensor, as explained in connection with FIGS. 9 and 10, the solar cell module 12 is measured with the exposed cross connectors 10, then to supply the position data of the controller of a handling device by means of the junction box 30 with exact position their contacts 28 is aligned with the cross connector 10, then to make the required electrical contact. In this case, two contact possibilities are shown in FIG. In Fig. 7, the cross connector 10 is connected to the terminal contact 28 of the junction box 30 fabric conclusive. This is done in particular by laser or induction soldering. According to the embodiment of FIG. 8, the terminal contact 28 is made with the cross connector 10 alternatively via a spring contact 34. Of course, other types of connection are also possible.

As can be seen from FIGS. 3 and 4, the layers 18, 20 are uncovered on the back side in several areas, specifically wherever transverse connectors extend, which are then to be electrically conductively connected to the connection box with a connection contact.

According to FIG. 3, four corresponding uncovered regions 26 of cross connectors 10 are shown by way of example.

Furthermore, it follows from FIGS. 3 and 4 once again the basic structure of a solar cell module. The corresponding layer structure can be seen in detail in FIG. 4.

In this case, the solar cell module 12 is viewed from the back, so that the first layer, the weatherproof plastic composite film of z. As polyvinyl fluoride and polyester (layer 20), below from z. B. ethylene vinyl acetate or silicone rubber existing layer 18, purely in principle solar cells 36, another consisting of transparent plastic layer 38 of z. B. ethylene vinyl acetate or silicone rubber and Finally, a front glass layer 40 can be seen. Of the series-connected or parallel solar cells 36 then go from the cross connector 10, which are connected to the contacts 28 of the junction box 30.

According to the invention, a laser-based removal of the back layers 18, 20 of the laminated solar cell module 12 in the regions of the cross connector 10, which are to be connected to the contacts 28 of the junction box 30. In this case, a reproducible fully automatic exposure of the cross connector 10, without damaging the adjacent areas of the solar cell module 12 takes place.

It can be achieved high surface removal rates, which are readily in the range between 150 mm ² / sec and 200 mm ² / sec at the usual back layer thicknesses, the thickness of which can be between 0.5 mm and 1 mm in total.

By accurately detecting the position of the cross connector 10 by means of z. As the image processing is ensured that the laser beam exclusively selected areas of the ablated layers 18, 20 applied. Coupling of the laser radiation in areas adjacent to the cross connector 10 can therefore be precluded to the extent that coupling into the glass 40 takes place, which otherwise could shatter. The cross connector 10 are exposed to an extent that a secure material conclusive connection with the terminal contacts 28 of the junction box 30 takes place.

Even if it is intended in principle to prevent any material present directly in the region of the contact from being removed, that is to say being acted on by the laser radiation which runs alongside the transverse connector 10 in order to preclude coupling of the laser radiation into the glass 40, the invention is not abandoned. if removal of material occurs in the upper region of the at least outer layer 20, if necessary also up to the upper region of the layer 18, which has an areal extent whose projection runs laterally next to the contact in the direction of the contact, so that a quasi-funnel shape resp in the section trapezoidally exposed area extending from the surface of the layer to the contact extends. Through the related measures men the advantage is achieved that the connection with the terminal contacts 28 is simplified.

An identical funnel-shaped or in section trapezoidal exposure can also be performed when z. B. contacts to be repaired, as will be explained in connection with FIGS. 9 and 10.

A further aspect of the teaching according to the invention will be explained with reference to FIGS. 9 and 10, on the basis of which faulty electrical contact can be repaired or renewed. In this case, the teaching is also explained with reference to a solar cell module, without thereby the fiction, contemporary teaching should be limited. Likewise, the same reference numerals are used in principle for the same elements.

Regardless of this, with respect to the laser system used or the laser, the parameters with which the laser system is operated or the nature and extent of the removal of the surface of the at least one layer consisting of plastic, which is located above the contact on the To refer to embodiments that have been set forth in connection with Figs. 1 and 8.

In Fig. 9, an arrangement is shown purely in principle, with which an electrical contact between a cross connector 110 and a cell or string connector 112 of a solar cell module 114 is exposed, then to connect them again electrically conductive.

For exposure, a laser scanner 116 is used, which in addition to a laser emitting laser, such as CO ₂ laser, deflection mirror and optics to move the laser beam 118 over a desired area of the solar cell module 114 to the cross connector 110 and the cell connector 112th Covering layers 120, 122 to remove by evaporation. It is a laser scanner used, the structure and operation of which are well known to one of ordinary skill in the art. According to the exemplary embodiment of the solar cell module 114, the layers 120, 122 are a transparent plastic layer, which extends from the transverse connector side and consists of, for example, a plastic layer. For example, ethylene vinyl acetate (EVA) or silicone rubber and these outside covering weatherproof plastic composite film made in particular Polyvi- nylfluorid (TEDLAR) and polyester.

In the region of the cross connector 110 extends below this another transparent plastic layer of z. Ethylene vinyl acetate or silicone rubber labeled 124. The corresponding unit is arranged on a glass plate 126 or other transparent carrier. The interconnected solar cells themselves are not shown, which are located between the layers 120 and 124.

After completion of the module, a functional test is performed. If it should turn out that there are errors in the interconnection or not sufficiently good electrically conductive contacts between the cross connectors and the string or cell connectors, then the module is discarded according to the prior art, otherwise the risk of inadmissible heating up to emergence during operation a fire arises.

On the basis of the teaching according to the invention, the module is checked to determine which electrical or which electrical contact is faulty or is defective. This can be done with an image processing as a sensor. But also by means of temperature sensors faulty contact points can be detected.

If the faulty contacts have been determined, the laser beam 118 is moved in accordance with a predetermined pattern, which is stored in the control of the laser scanner 116, via the area or areas to be exposed. In this case, an energy input takes place to such an extent that the layers 120, 122 extending above the cross connector 110 and the string connector 112 or vaporize.

Pattern here means or includes how the laser beam is moved to the contact to be repaired or which laser power is used. Also width the laser beam impinging on the layer to be removed or other parameters required for the application of the laser radiation may include the term pattern.

According to the invention, it is avoided that the laser beam can impinge on the layers 120, 122 outside of the contact to be repaired to such an extent that a coupling into the glass plate 126 takes place. This can be z. B. done by a template or an applied clearance contour. By means of this, an area is released for the radiation which is smaller than that of the contacts to be repaired. Uncovered contour means that the layer or layers which cover the contact to be repaired are covered in the areas to which the laser beam should not impinge. It releases the areas where you want to remove it to repair the contact.

The movement of the laser beam 118 can take place-as explained above-in meandering or zigzagging or linear fashion along parallel straight lines. However, it is essential that a uniform removal, ie a uniform evaporation of the layers 120, 122 takes place above the contact point. Therefore, in the event that the mirror or mirrors of the laser scanner 116 are stopped, a turn-on delay for the laser is provided.

This means that at standstill of the mirror or laser light does not impinge on the module 114, so the laser 118 is turned off.

With regard to the spacing of the laser lines, their width, the type of laser system used, duty cycles and speed and nature of the area to be crossed, reference should be made to the statements in connection with FIGS. 1 to 8. The same applies to the area removal rate or other explanations.

According to the invention, a laser-based removal of the back-side layers 120, 122 of the laminated solar cell module 114 takes place in the regions in which electrical components are present. clock connections to be repaired. In this case, a reproducible fully automatic exposure of the contact point.

By accurately detecting the position of the contact point by means of the sensor, such as image processing, it can be ensured that the laser beam 118 acts exclusively on the regions of the layers 118, 120 to be removed which run above the contact point. A coupling of the laser radiation in the adjacent areas and thus in the glass 126 is excluded, which could otherwise shatter. The contact point is thereby exposed to an extent that a secure cohesive bonding between the cross connector 110 and the or the cell or string connectors 112 takes place.

Claims

Claims 1. A method for exposing an electrical contact

A method for exposing at least one electrical contact of a solar cell or a solar cell module covered by at least one layer, preferably made of plastic,

characterized by the method steps

Determining the position of the at least one contact by means of a sensor, removing the at least one layer by means of a laser beam of a laser scanner, taking into account the determined position and a stored in a control of the laser scanner pattern

wherein the at least one layer is removed in a flat area, the projection of which lies in the direction of the contact within or substantially within it.

2. The method according to claim 1,

characterized,

that a plurality of electrical contacts in the form of cross connectors of a laminated solar cell module are exposed and connected to contacts of a junction box, wherein the cross connector solar cell module back are covered by a transparent plastic layer and a plastic film and the plastic layer and the plastic film are removed by means of the laser beam.

3. The method according to claim 1,

characterized,

that the electrical contact is a faulty contact which is repaired or renewed after the removal of the at least one layer.

4. The method according to at least one of the preceding claims, characterized

that the area of the layer within which the contact is exposed is uncovered by means of a template or an exposed contour.

5. The method according to at least one of the preceding claims,

characterized,

that a laser scanner with a two-axis scanning system with preferably planar field optics or a three-axis scanning system is used.

6. The method according to at least one of the preceding claims,

characterized,

that a CO ₂ laser system is used.

7. The method according to at least one of the preceding claims,

characterized,

a pulsed laser system is used whose pulse frequency v is v> 5 kHz, in particular v> 10 kHz.

8. The method according to at least one of the preceding claims,

characterized,

in that for removing the at least one layer of plastic material for ablation the laser beam used for ablation is moved over the surface to be ablated at a speed V, wherein 200 mm / sec <V <7500 mm / sec, in particular 2000 mm / sec <V <4000 mm / sec, preferably 3300 mm / sec <V <3700 mm / sec.

9. The method according to at least one of the preceding claims,

characterized,

in that, to remove the at least one layer consisting of plastic, the laser beam is moved several times over the surface to be removed.

10. The method according to at least one of the preceding claims,

characterized,

in that for removing the at least one layer consisting of plastic the laser beam is moved two to five times, in particular two to three times, over the surface to be removed.

11. The method according to at least one of the preceding claims,

characterized,

the laser beam is moved meandering or zigzagging over the surface to be removed.

12. The method according to at least one of the preceding claims,

characterized,

the laser beam is moved along lines running parallel to one another over the surface to be removed, the distance between the lines being 0.05 mm to 0.2 mm, in particular between 0.1 mm and 0.2 mm.

13. The method according to at least one of the preceding claims,

characterized,

that the laser system is operated delayed in the edge region of the ablated surface.

14. The method according to at least one of the preceding claims,

characterized,

the laser system is operated in such a way that the pulse widths lie between 10 μs and 400 μs.

15. The method according to at least one of the preceding claims,

characterized,

that the laser is operated such that the removal rate between 75 mm ² / s and 225 mm ² / s, preferably 100 mm ² / s and 200 mm ² / s with a layer thickness to be removed between 0.5 mm and 1.0 mm ,

16. The method according to at least one of the preceding claims,

characterized,

the laser beam is spot-focused onto the surface to be removed with a diameter D of 0.3 mm <D <1.2 mm, in particular 0.4 mm <D <0.8 mm.

17. The method according to at least one of the preceding claims,

characterized,

that the laser system with a power P with 100 watts <P <1000 watts, in particular 200 watts <P <400 watts, is operated.

18. The method according to at least one of the preceding claims,

characterized,

in that an optical sensor with image processing is used as the sensor.

19. The method according to at least one of the preceding claims,

characterized,

in that a temperature-measuring sensor is used as the sensor.

20. Method according to at least one of the preceding claims,

characterized,

the optical sensor is positioned relative to the laser scanner on the opposite side of the at least one electrical contact.

21. Method according to at least one of the preceding claims,

characterized,

the position of the at least one electrical contact is determined optically in the transmitted-light method.

22. Method according to at least one of the preceding claims,

characterized,

the position of the at least one electrical contact is determined inductively.

23. Method according to at least one of the preceding claims,

characterized,

the position of the at least one electrical contact is determined by means of ultrasound.

24. Method according to at least one of the preceding claims,

characterized,

in that the at least one electrical contact is strip-shaped, which is sealed in its edge regions delimiting the exposed surface by material of the at least one plastic layer which has been melted by means of the laser beam.

25. Method according to at least one preceding claim,

characterized,

that the exposed electrical contact is renewed by means of soldering, such as laser soldering, in its materially coherent connection.

26. Method according to at least claim 2,

characterized,

that after exposing the cross connector, the solar cell module by means of a handling device on the exposed areas of the cross connector, the contacts of the junction box and then these force and / or materially connected to the exposed areas.

27. Method according to at least claim 2,

characterized,

in that, during the electrically conductive connection of the exposed areas with the contacts or thereafter, the junction box is connected to the solar cell module, preferably by means of silicone or adhesive tape.

28. Method according to at least claim 2,

characterized,

the position of the solar cell module is detected with the exposed areas by means of an image processing and data thus obtained are transmitted to a controller of a handling device for aligning the contacts with the uncovered areas.

29. The method according to at least claim 1,

characterized,

material is removed from the surface of the at least one layer to be removed in the direction of the contact in such a way that a funnel-shaped opening results in the at least one layer, wherein projection of the opening in the region of the surface in the direction of the contact is partially outside thereof and projection of the contact is located on the contact abutting opening within the contact.

30. The method according to at least claim 1,

characterized,

that the laser beam immediately above the contact removes a portion of the layer whose projection in the direction of the contact lies exclusively within the contact.