Abstract:
A device for structuring a solar module. A retainer device arranged above the solar modules to be machined comprises retainer means which retain the solar modules. The retention is achieved in a non-contact manner. In a region beneath the solar module a structuring tool is arranged mounted to be mobile in a longitudinal and a transverse direction. The structuring tool can thus machine the complete surface of the solar module.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a National Stage Application of PCT/CH2009/000203, filed Jun. 15, 2009, which designates the United States and claims the priority of European Patent Application No. 08405163, filed on Jun. 25, 2008. 
     
    
     BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to a device for structuring a solar module. 
         [0004]    2. Related Art 
         [0005]    Solar modules in solar energy systems comprise substantially flat glass plates, which are coated on one side. The coating usually consists of multiple layers overlaid on one another, of which at least one layer is electrically conducting. For technical reasons relating to production the glass module is fitted contiguously with the coating. In order to generate an acceptably high electrical current the applied coating must be divided into individual sections. As well as a purely mechanical structuring of the surface using appropriate tools, an optical structuring of these solar modules has also established itself. 
         [0006]    In the optical structuring the coating is produced by means of a laser, which burns thin to very thin discontinuities into the coating with a certain degree of precision. 
         [0007]    A system for structuring solar modules is known from DE 10 2006 033 296 A1. This structuring system comprises a transport system with which a glass module can be transported within the system. For transporting and retaining the solar module the transport system is equipped with a plurality of air nozzles, by means of which the solar module floats on an air bearing. The coating is located on the upper side of the solar module remote from the transport system. A structuring tool, namely a laser, is arranged underneath the transport system and the glass plate to be structured. The laser is displaceable perpendicular to a transport direction of the solar module. 
         [0008]    In order to structure the coating, the focus of the laser is directed on to the region of the coating, wherein a laser beam passes through the glass plate of the solar module. In the focussing range of the laser the coating is vaporised, which allows the desired discontinuity to be produced. 
         [0009]    To achieve a structuring in the longitudinal direction of the solar module, which corresponds to a transport direction of the module, the module must be displaced over a working range of the laser. On account of the air nozzles arranged underneath the glass plate, the working range corresponds to only a small gap extending perpendicular to the transport direction. To perform the structuring the glass is displaced over this working range, this procedure being repeated as often as necessary until the structuring of the solar module has been completed. 
         [0010]    Above the working range a suction device is arranged, which sucks particles or waste gases resulting from the structuring process away from the surface of the solar module, which could otherwise remain in place and possibly adversely affect a repeated structuring displacement of the laser even if only in a neighbouring region. 
         [0011]    On account of the transport system, which is arranged underneath the solar module, the mobility of the laser is considerably restricted. The latter is, as explained above, only moveable perpendicular to the transport direction of the solar module. To structure the module it must be moved over the laser again and again. The glass plate therefore may be moved only with extreme care, as due to the thickness of the glass the glass plate can easily be broken. In particular a high acceleration represents a loading on the glass plate that is to be avoided. This results in a relatively slow machining of the solar module with the laser. 
         [0012]    In addition to the relatively restricted mobility of the laser, limiting of the accuracies of the focussing range and of the individual tracks is found. In particular, with the arrangement of the laser and the movement of the glass the structuring cannot be adjusted later, which adversely affects the accuracy and therefore the quality of the solar modules. 
       SUMMARY 
       [0013]    A problem addressed by the invention is to improve a device of the type mentioned initially, by means of faster machining times and a higher machining quality. 
         [0014]    A device for solving the problem according to the invention is provided. The solar module is retained on an upper side facing away from the structuring tool. The solar module is introduced into the device with a coated upper side facing upwards, where it is retained by a retaining device arranged on this same side. An underside of the solar module therefore remains free, wherein the possible risks of damage to the coating due to the retaining device are minimised. Thus, any falling objects, for example, are not left lying on the retaining device. The upper side of the solar module is not guided past stationary objects, which could be the cause of damage. 
         [0015]    According to an embodiment of the invention, retention of the solar module is achieved in a non-contact manner. Due to the non-contacting retention, the risk of damaging the solar module is minimised. Glass that is thin and of fairly low quality is preferably used to manufacture a solar module. This glass however is not only lower in cost than high-quality plate glasses, but also more fragile to handle. A non-contact method of handling the solar module can therefore contribute to reducing damage caused, or even protecting against glass breakage. 
         [0016]    In another embodiment of the invention, the retaining device comprises at least one, preferably a plurality of, retainer means. These retainer means are distributed evenly over the upper side of the solar module. The even distribution reduces deformations in the glass, and therefore contributes to a more accurate structuring and prevention of damage. To achieve a non-contacting retention, a negative pressure is generated on the upper side of the solar module by the retainer means by means of compressed air. The retainer means holds the module by suction due to compressed air blown out radially on to the top of the solar module, which is referred to as the Bernoulli principle. Between the retainer means, also known as a Bernoulli gripper, and the solar module a small gap is formed by the escape of compressed air. The solar module therefore floats underneath the retaining device. 
         [0017]    In a further embodiment of the retainer means, to achieve a non-contacting retention the retainer means sucks up the module by means of suction air. By means of compressed air an air cushion is formed at the same time. The solar module therefore, held by the suction air, floats underneath the retaining device. 
         [0018]    The structuring tool is arranged so that it can freely move underneath the retaining device. Due to the elimination of a retaining device under the glass module, the space can therefore be used for the structuring tool. The retaining device with the retainer means holds the solar module immobile in one position, so that the structuring tool that moves underneath the solar module can apply the structure to the coating. In addition the service lifetime of the structuring device is also improved by the free space underneath the retaining device. In the event of glass breakage, with the device according to the invention there is no need for costly cleaning of the transport system. Glass shards can be simply left in the free space and removed at a later date. 
         [0019]    In another embodiment the structuring tool comprises at least one carriage and at least one laser, for example, a plurality of lasers. The lasers are moveable in a longitudinal and a transverse direction. The plurality of lasers enables a faster machining time for the solar module, since multiple discontinuities can be burnt into the coating by the lasers at the same time. The lasers are also insensitive to accelerations, under which the glass of the solar modules would break. This makes an additional acceleration in the structuring possible. 
         [0020]    According to another embodiment the carriage has a bearer, on which lasers are arranged, and which can be displaced in the longitudinal direction on two parallel running guides. The lasers themselves are displaceable on the bearer in the transverse direction of the structuring tool. The lasers can thus be moved in two dimensions under the solar module to be machined. With the two-dimensionality moreover, it is possible to implement parallel or simultaneous movements in the longitudinal direction and the transverse direction of the solar module. The guides are arranged in the longitudinal direction of a glass module, so that the bearer can be displaced smoothly. 
         [0021]    According to another embodiment, at each of its free ends the bearer comprises a chassis which mates with one of the guides. By means of the chassis the carriage is connected to the guides, which means an exact trajectory of the bearer is achieved. The bearer is arranged perpendicular to the longitudinal direction of the guides. The bearer itself also comprises a guide, in which the laser or lasers are arranged. Each of the lasers is accommodated in an approximately shoebox-sized box, wherein the boxes, as already mentioned, can withstand high accelerations, up to 10 g. The boxes with the lasers are preferably arranged immediately next to one another on the bearer and parallel over a longitudinal extension of the bearer. Primarily the lasers are displaced en bloc, but they can also be controlled individually, so that for example one or more lasers can be positioned in the region of the one end, one or more lasers at another end and again, one or more lasers in a central region of the bearer, in order to be arranged next to one another again from there. 
         [0022]    According to another embodiment of the invention the guide is arranged in a plane with the solar module. By means of this arrangement possible movements of the laser have no effect on the accuracy of the focussing point of the laser on the upper side of the glass plate. The movements are referred to as “pitching”, “rolling” and “yawing” and determine a direction of rotation of three axes passing through the laser. It is also possible however to let the plane of the module correspond to a rotational axis or to a point of the chassis that serves to ensure accuracy. 
         [0023]    In a further embodiment of the invention, an area of free space is left underneath a machining region of the structuring tool. With the arrangement of the retaining device above the solar module the device can be designed to be substantially smaller, but in particularly a construction carrying the retaining unit can also be formed by a compound table. The compound table facilitates a lighter construction for the client, since the ability of the device to be transported is simplified. The space is therefore free, so that there is room here for any glass plates or shards of broken glass plates that fall down. As already mentioned above, broken glass plates do not need to be removed immediately from the device, since they have no effect on any working process. Any cleaning required can take place at a later date. Alternatively a collecting pan can be provided, in which the shards can be caught. 
         [0024]    According to another embodiment, the retaining device is freely rotatable by 90° parallel to a plane of the solar module. The structuring of the coating on the solar module can be very complex and comprise different shapes. To this end it is necessary to allow the laser beam to pass not only perpendicular to and along the glass plate, but also diagonally or at an angle to a side of the glass plate. By rotation of the retaining device and the glass plate retained thereon this structuring direction can be implemented with little effort. 
         [0025]    The retaining device serves to remove by suction any layer particles vaporised and burned off by the laser. The laser heats up the coating of the solar module in the area of its focussing region, which means that the coating is heated up and burned off or vaporised. This causes dirt particles to form on the top of the solar module, which must be removed. According to an embodiment of the invention the retaining device is formed from a plurality of Bernoulli grippers, which apply compressed air to the top. The air escapes from the grippers to the side and therefore in a simple manner transports the dirt particles away from the solar module, which are captured by the air stream of one or more grippers. Waste gases arising from the combustion can also be removed to the side by the strong flow. To the side in a region of the edges or of the solar module or above it, a suction device is provided which draws off the waste gases and dirt particles. 
         [0026]    According to another embodiment, a positioning aid is arranged to the side of the solar module, which lies at least partly in the plane of the solar module. The positioning aid enables the positioning and/or fixing of the solar module. By means of the touch-free or contact-free retention of the solar module using the retaining device, the solar module could be displaced laterally. To avoid lateral movements the positioning aid serves as a stop edge, with which the solar module is retained laterally. This results in the advantageous possibility of coating the entire upper side with a single coating and also of machining this using the laser. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0027]    An embodiment of the invention will now be discussed with the aid of the drawings. They show: 
           [0028]      FIG. 1  a perspective side view of the device according to an embodiment of the invention from a first long side, 
           [0029]      FIG. 2  a perspective side view of the device according to an embodiment of the invention from a second long side, 
           [0030]      FIG. 3  a perspective view from underneath the device according to an embodiment of the invention, 
           [0031]      FIG. 4  a top view on to the device according to an embodiment of the invention, 
           [0032]      FIG. 5  a front view of the device according to an embodiment of the invention, and 
           [0033]      FIG. 6  an extracted view of the structuring tool with retaining device. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]      FIGS. 1 and 2  of the drawings show the device according to an embodiment of the invention in perspective view from a first and second long side. The device comprises a sub-frame  1 , which is formed of transverse struts  2 , longitudinal struts  3  and feet  4 . The sub-frame  1  is formed in the manner of a compound table. On the undersides of the feet  4  adjustment devices  5  are arranged, with which unevennesses in the base underlying the device can be compensated for. 
         [0035]    Lateral mounting elements  6 ,  7  are arranged on each of three feet  4  located on long sides of the sub-frames  1 . On their top side the feet  4  form a horizontal plane, by means of which the mounting elements  6 ,  7  are mounted horizontally. By means of the adjustment devices  5  on the feet  4  final adjustments can be made for a horizontal mounting of the sub-frame  1 . In addition, a connecting element is placed between each of the feet  4  and the mounting elements  6 ,  7  respectively. The connecting element serves to make a connection between a foot  4  and the mounting element  6 ,  7 . The respective connecting element also comprises an adjustment facility, with which the mounting elements  6  and  7  can additionally be brought into a horizontal position. 
         [0036]    The mounting elements  6 ,  7  are of solid construction and have a low thermal expansion coefficient. The mounting element  6 ,  7  is constructed as an inverse L-bracket. The underside of the L forms the top of the mounting element  6 ,  7 , wherein an inner side of the members of the mounting element  6 ,  7  positioned relative to one another points in the direction of the other mounting element  6 ,  7 . The part of the mounting element  6 , resting on the feet  4  is larger in its physical dimensions than the other member forming the upper side. 
         [0037]    A retaining device  9  is positioned between the opposite lying mounting elements  6  and  7 . Bearing elements  11  are positioned in the region of outward facing edges  10  of the mounting elements  6  and  7 , which are rigidly connected to the mounting elements  6  and  7 . The bearing elements  11  therefore extend over the entire width of the device. Altogether, three such bearing elements  11  are shown in the figures, which are arranged next to one another. In other embodiments of the device however it may be necessary to provide more or fewer bearing elements  11  than those shown. The bearing elements  11  are designed to accommodate large loads. 
         [0038]    On an underside of the bearing elements  11 , mutually parallel U-profiles  12  are arranged. The U-profiles  12  are attached to a member on the underside of the bearing elements  11 . On another member, lying parallel to the member connected to the bearing element  11 , retainer means  13  (see  FIG. 6 ) are arranged. The retainer means  13  lie on an outer side of the U-profile  12  and point in the direction of sub-chassis  1 . Each U-profile  12  comprises a plurality of retainer means  13 . The retainer means  13  are distributed evenly on the underside of the bearing elements  11  with the U-profiles, wherein as small a grid of retainer elements  13  as possible is provided. 
         [0039]    Also on the upper side  8  of the mounting elements  6  and  7  a guide  14  is arranged. The guide  14  is arranged in a region of an inner edge  15  of the mounting elements  6  and  7 . The guides  14  extend exactly parallel to one another. Chassis  16  are guided in the respective guides  14  of the mounting elements  6  and  7 . The chassis  16  extend at least in part above the guides  14  and are bounded from above by the bearing elements  11 . In the region of the guides  14  the bearing elements  11  are spaced apart from them. The chassis  16  can therefore be guided through between the bearing elements  11  and the guide  14 . 
         [0040]    The chassis  16  is constructed to be broader than the guide  14  and projects beyond the inner edge  15 . On the chassis  16  a retainer  17  is arranged at the side, which extends underneath the inwardly pointing member of the bearing element  6 ,  7 . The retainer  17  also extends outside of the chassis  16 , i.e. it rests on the chassis. To an underside of the respective retainers  17  a bearer  18  is attached, which extends between the retainers  17  and joins them together. The construction consisting of chassis  16 , retainer  17  and bearer  18  forms a so-called carriage  19 . The retainer  17  extends vertically from the chassis  16  to the bearer  18  along the inner edge  15 . The bearer  18  itself extends laterally outwards over the respective retainers  17 . The bearer  18  therefore lies at least partly underneath the upper side  8  and the guide  14 . The bearer  18  is bounded to the side by the member of the mounting elements  6  and  7  connected to the feet  4 . 
         [0041]    The bearer  18  also comprises a guide, which in the exemplary embodiment according to the invention is in the form of a rail. The rail  20  extends over the entire length of the bearer  18 . The rail  20  is attached to an outer side of the bearer  18 , wherein it is connected to it on an outer side of the bearer  18 . 
         [0042]    A plurality of lasers  21  are arranged on the bearer  18 . The lasers  21  are moveably connected to the rail  20 . The lasers  21  are moveable laterally on the bearer  18  over the width of the device. The lasers are accommodated in respective boxes, which are individually connected to the rail  20 . Therefore, the lasers  21  can be moved over the bearer  18  separately or as a unit. The lasers  21  are aligned in the direction of the retaining device  9 . A laser beam from the respective lasers  21  thus extends in a vertical direction. 
         [0043]    The carriage  19  with the lasers  21  attached to the bearer  18  is moveable in a longitudinal direction of the device, that is, along the mounting elements  6  and  7 . At the same time the lasers  21  can be displaced perpendicularly to this motion. In the exemplary embodiment shown in  FIG. 1-6 , four lasers  21  are arranged on the bearer  18 . In further embodiments of the invention however, more or fewer lasers are also provided. 
         [0044]    The retaining device  9  serves to retain a solar module  23  consisting of plate glass. The solar module  23  is thus retained by the retainer means  13  underneath the retaining device  9 . The retainer means  13  are in the form of so-called Bernoulli grippers. The Bernoulli grippers generate a negative pressure by means of an air stream blown on to a surface of the solar module  23 , with which the solar module  23  onto which the air is blown is sucked towards the Bernoulli grippers. Due to the large number of the retainer means  13  constructed as Bernoulli grippers positioned on the retaining device  9 , large objects, such as for example a solar module  23 , can be retained. Due to the escaping air stream, which is blown on to the surface of the solar module  23  by the Bernoulli grippers, no contact takes place between solar module  23  and retainer means  13 . Between the solar module  23  and the Bernoulli grippers there remains a small gap, through which the escaping air flows out either laterally or radially. 
         [0045]    The solar module  23  comprises a coating on the upper side on to which air is blown, which points in the direction of the retainer means  13 . To perform the structuring of this coating, the lasers  21  are moved underneath the solar module  23  on the carriage  19  across the full extent of the solar module  23 . The solar module is smaller than a plane defined by the mounting elements  6  and  7 , which means the lasers  21  reach the entire area of the solar module  23 . The lasers  21  burn a structuring into the coating from underneath the solar module, in the form of discontinuities, the coating being burnt off or vaporised. Due to the non-contacting retention of the solar module  23  therefore, the structuring process can also take place in the region of the retainer means  13  (Bernoulli grippers). Displacement of the solar module  23  and of the retainer means  13  is therefore eliminated. By means of the air stream, which is blown by the Bernoulli grippers on to the surface of the solar module  23 , particles produced by the combustion of the coating are carried away. In addition, gases produced in the combustion are blown away. Not shown are one or more suction devices, which are arranged both above the retaining device  9  and to the side of it. A suction device receives the particles and gases blown away by the Bernoulli grippers. 
         [0046]    Not shown in the Figures is a positioning aid, which holds the solar module in position laterally. By retaining the solar module  23  in a non-contact manner using the retaining device  9  the solar module  23  can be displaced by external effects. For the structuring of the coating of the solar module  23  however, it is important that the solar module  23  is held in position. The positioning aid can therefore consist of a rod or any other means of positioning, which is brought towards the solar module  23  from the side. It is provided that the solar module  23  is secured in every possible direction. 
         [0047]    In another exemplary embodiment, not shown, the retaining device  9  can be rotated parallel to a plane of the solar module  23 . Here it is sufficient for the solar module  23  to be turned by 90° either clockwise or anti-clockwise. The structuring of a solar module  23  is very complex, so that by the rotation of the retaining device  9  with the solar module  23  the machining time can be shortened. 
         [0048]    The structuring with the lasers  21  requires an accurate guiding of the laser  21  underneath the solar module  23 . In fact the burning off of the coating on the upper side of the solar module  23  takes place only in a focussing range of the laser beam. To avoid inaccuracies in the guiding of the laser it is provided, among other things, that the solar module  23  is retained at the height of the guide  14 . At least however, it is provided that one rotational axis of the carriage  19  lies on the level of the solar module  23 . By means of this arrangement the focussing range of the laser  21  remains stable in the region of the coating of the solar module  23 . 
         [0049]    While embodiments of the invention have been described herein, it should be understood that it has been presented by way of example only, and not limitation. Thus, the breadth and scope of the invention should not be limited by any of the described embodiments, but should instead be defined only in accordance with the following claims and their equivalents.