WO2012127411A1

WO2012127411A1 - Systems and methods for making atleast a detachable electrical contact with atleast a photovoltaic device

Info

Publication number: WO2012127411A1
Application number: PCT/IB2012/051316
Authority: WO
Inventors: Jonas Hiller
Original assignee: Pasan Sa
Priority date: 2011-03-23
Filing date: 2012-03-19
Publication date: 2012-09-27
Also published as: CN103597739B; EP2689258B1; EP2689258A1; CN103597739A; TW201244117A; KR20140019804A; JP2014509088A

Abstract

The present invention provides system and method for making atleast a detachable electrical contact with atleast a photovoltaic device for testing the photovoltaic device. The system comprises atleast a support member and a plurality of contact members adapted to establish the detachable electrical contact with atleast the photovoltaic device, wherein a single piece of a material is adapted to form the support member and the contact members.

Description

SYSTEMS AND METHODS FOR MAKING ATLEAST A DETACHABLE ELECTRICAL CONTACT WITH

ATLEAST A PHOTOVOLTAIC DEVICE

FIELD OF THE INVENTION

[001] The present invention relates generally to testing photovoltaic device, and more particularly to, systems and method for making atleast a detachable electrical contact with atleast a photovoltaic device for testing the photovoltaic device in a cost effective, environmentally safe, and secure manner.

BACKGROUND OF THE INVENTION

[002] A solar cell is a solid state device that converts the energy of sunlight directly into electricity by the photovoltaic effect. Assemblies of solar cells are used to make solar modules, also known as solar panels. The energy generated from these solar modules, referred to as solar power, is an example of solar energy. Photovoltaics is the field of technology and research related to the practical application of photovoltaic cells in producing electricity from light, though it is often used specifically to refer to the generation of electricity from sunlight.

[003] Photovoltaic cells also called solar cells are semiconductor devices which transform light in electrical power. Nowadays most of the commercially sold photovoltaic cells are crystalline solar cells, which consist of doped silicon wafers. In order to establish electrical contact with such cells contacts are provided, e.g. a metallization layer is applied on the backside and on the topside of these wafers. Usually the backside metallization covers the whole backside area whilst the topside metallization consists of very narrow fingers and two or more bus bars.

[004] In order to get higher power, solar cells are interconnected and assembled in solar modules. These solar modules consist of several cells, which are electrically connected in series. The topside metallization of one cell is linked to backside metallization of the next cell, using metal ribbons called tabs. These ribbons usually are soldered on the cells in order to minimize contact resistivity and to get a uniform electrical contact over the whole bus bar.

[005] At the end of the cell production, and before the cells are assembled in solar modules, the solar cells are tested in order to determine their quality. The existing measurement technologies to evaluate different cell properties includes Electroluminescence imaging, shunts thermal imaging, and the IV-curve measurement, using a sun simulator wherein the cells have to be electrically connected with a measuring device. [006] Electroluminescence is an imaging technology which uses the inverse principle of a photovoltaic cell. The electroluminescence imaging setup may consist in an electrical contacting system for the cell and a camera system. The whole system has to be installed in a dark room in order to be impressed only by the very low intensity of the electroluminescence radiation. Instead of transforming photons in electrons, a current is imposed in the cell and photons are created in the active areas of the cell. The active area is the entire cell surface wherein photons are generated. The photons just may not leave the cell directly as they may be reflected from the back contact and thus circumvent the fingers or bus bar. The emitted photons in these areas may be visualized by the use of highly sensitive digital cameras.

[007] In IV-curve measurement technique which is a functional indoor test of the cell, a sun-like light source, an electric contacting system and electronic measuring equipment may be used. The cell is connected to the measuring device and during the sun-like illumination of the cell, electrical measurements are made. A variable load may be active or passive, sweeps the whole range of device characteristics, for example, from short circuit to open circuit, in order to collect the current versus voltage curve of the cell.

[008] In both Electroluminescence imaging and the IV-curve measurement techniques, it is important to have an electric contact system which covers a minimum of the active area on the cell's top side wherein photons are created. An optimal electric contact system may thus be restricted on these inactive areas and cast only a minimum of shadows on the active area.

[009] Furthermore it is important for IV-curve measurements to have electrical contacting properties which are very similar to the use of soldered ribbons. Contact resistivity has to be very low (comparable to a solder joint) and the contact points may be equally distributed over the whole bus bar, so that the ohmic resistance of the bus bar is in parallel to that of the connector as it is the case with a soldered ribbon.

[0010] Generally, two main approaches, namely, spring probes and bent wires, exist for electrical contacting of solar cells. Spring probes consist of needle pins, guided in a tube and preloaded by springs. For contacting the bus bar of the solar cell, an array of several spring probes are aligned over the bus bar and are fixed on a fixation bar. These designs require many delicate assembly steps. The needle pins are very delicate and are easily damaged. The cross section of the contact areas is also very small as compared to that of ribbons connected to the bus bar. Also the array of spring probes is repeated for each bus bar. [0011] In case of bent wires approach, bent metallic wires are used which are aligned on the bus bar. They are fixed outside the cell area in order to minimize the cast shadows on the solar cell. Precise alignment of the wire tips on the bus bar requires delicate assembly. Also the cross section of the contact is very small and the number of contact point is limited by the complicated design.

[0012] Accordingly, the present scenario is necessitating the need for a new system which is capable of overcoming disadvantages inherent in the conventional photovoltaic testing techniques by making a detachable electrical contact with atleast a contact area of atleast a photovoltaic device for testing the photovoltaic device such that the time for contacting and releasing the photovoltaic device may be minimal and shocks on the photovoltaic device may be prevented to avoid cracks, micro cracks or destruction of the surface of the cell.

SUMMARY OF THE INVENTION

[0013] In view of the foregoing disadvantages inherent in the prior arts, the general purpose of the present invention is to provide an improved combination of convenience and utility, to include the advantages of the prior art, and to overcome the drawbacks inherent therein in a cost effective, environmentally safe, and secure manner.

[0014] In one aspect, the present invention provides a system for making a detachable electrical contact with atleast a photovoltaic device for testing the photovoltaic device such that the time for contacting and releasing the photovoltaic device may be minimal and shocks on the photovoltaic device (fragile silicon cells) may be prevented in a cost effective, environmentally safe, and secure manner. The electronic contact may be very similar to the use of soldered ribbons, for example, a large area of the contact (bus bar) may be contacted and may cover a minimum active area of the of photovoltaic cell such that no or atleast limited shadow may be cast onto the active region of the photovoltaic device. All light of the sun simulator may reach the surface of the photovoltaic device.

[0015] In one aspect, the present invention provides a system for making atleast a detachable electrical contact with atleast a photovoltaic device. The system comprises atleast a support member and a plurality of contact members protruding towards the bus bar and inclined at an angle from the face of the support member, such that the plurality of contact members are adapted to make the detachable electrical contact with the bus bar of the photovoltaic device. Normally such systems are provided for each bus bar. [0016] In another aspect, the present invention provides an apparatus for testing atleast a photovoltaic device. The apparatus comprises atleast the photovoltaic device having a top side with a plurality of current gathering fingers and atleast a bus bar and a bottom side with a metallic coating, such that the bus bar and the metallic coating are electrically conductive, atleast a system for making atleast a detachable first electrical contact with atleast the contact area (bus bar) on the top side of the photovoltaic device, and a ground plate to make atleast a second electrical contact with the bottom side of the photovoltaic device, such that the first electrical contact and the second electrical contact connect the photovoltaic device to a current measurement means to test the photovoltaic device. As a variant according to the present invention, the plate member may be replaced by any one of the system and the apparatus of the present invention.

[0017] In another aspect, the present invention provides a method for making a detachable electrical contact with a bus bar of a photovoltaic device, to facilitate testing of the solar cell. The method comprises atleast a step of pressing the system according to the present invention onto the surface of the solar cell such that the contact members of the system make electrical contact with all of top surface of bus bar of the solar cell.

[0018] These together with other objects of the invention, along with the various features of novelty that characterize the invention, are pointed out with particularity in the claims annexed hereto and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] While the specification concludes with claims that particularly point out and distinctly claim the invention, it is believed the expressly disclosed exemplary embodiments of the present invention can be understood from the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify the same elements. The drawings and detailed description which follow are intended to be merely illustrative of the expressly disclosed exemplary embodiments and are not intended to limit the scope of the invention as set forth in the appended claims. In the drawings:

[0020] FIG. 1 illustrates a schematic diagram of a photovoltaic device, according to an exemplary embodiment of the present invention;

[0021] FIG. 2 illustrates a string , according to an exemplary embodiment of the present invention; [0022] FIG. 3 illustrates the spring probe approach of electrical contacting, according to the state of the art;

[0023] FIG. 4 illustrates the bent wire approach of electrical contacting, according to the state of the art;

[0024] FIGS. 5 and 5 A illustrate a system for making a detachable electrical contact with a bus bar of a photovoltaic device, according to an exemplary embodiment of the present invention;

[0025] FIG. 6 illustrates the delimiter, according to an exemplary embodiment of the present invention;

[0026] FIG. 7 illustrates the stoppers, according to an exemplary embodiment of the present invention;

[0027] FIG. 8 illustrates the headed contacts on the contact members, according to an exemplary embodiment of the present invention; and

[0028] FIGS. 9 and 9 A illustrate an apparatus for testing a photovoltaic device, according to an exemplary embodiment of the present invention.

[0029] Like reference numerals refer to like parts throughout the several views of the drawings. Further, in the drawings all sub-entities or parts of the system are delimited with black lines, however, these lines are just for clarity and the present invention may have one single block of material without any borders between the sub-entities or parts.

DETAILED DESCRIPTION OF THE DRAWINGS

[0030] The exemplary embodiments described herein detail for illustrative purposes are subject to many variations of structure and design. It should be emphasized, however that the present invention is not limited to particular system or methods for making atleast a detachable electrical contact with atleast a contact area of atleast a photovoltaic device as shown and described. Rather, the principles of the present invention may be used with a variety of electrical contact making and testing photovoltaic device methods and structural arrangements. It is understood that various omissions, substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but the present invention is intended to cover the application or implementation without departing from the spirit or scope of its claims. [0031] In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these specific details.

[0032] As used herein, the term 'plurality' refers to the presence of more than one of the referenced item and the terms 'a', 'an', and 'atleast' do not denote a limitation of quantity, but rather denote the presence of atleast one of the referenced item. The term 'device' also includes 'engine' or 'machine' or 'system' or 'apparatus'. The terms 'contact area', 'contact' and 'bus bar' may also be used herein interchangeably to refer to the same thing. The term 'horizontal' refers to a plane of the photovoltaic device and the term 'vertical' refers to a direction perpendicular to the plane of the photovoltaic device.

[0033] The terms 'photovoltaic device', 'photovoltaic cell', 'solar cell' and 'cell' may also be used herein interchangeably to refer to the same thing. Solar cells may be of any technology, such as thin film, crystalline, hetero junction (HIT) etc.

[0034] In an exemplary embodiment, the present invention provides system and method for making atleast a detachable electrical contact with atleast a bus bar or contact of atleast a photovoltaic device. The system of the present invention may be mass produced inexpensively and provides user an easy, robust, efficient, secure, cost effective, environment friendly and productive way of making a detachable electrical contact with atleast a photovoltaic device for testing the photovoltaic device.

[0035] Referring to FIG. 1 which illustrates a schematic diagram of a photovoltaic device 10, according to an exemplary embodiment of the present invention. The photovoltaic device 10 may have a top surface with a plurality of fingers 12 and a plurality of bus bars 14 (also referred to as 'contact area') connected across the fingers 12 to collect the electric charge generated. On a bottom surface of the photovoltaic device 10, a metallization layer 16 may be applied usually to the whole bottom surface. The bus bars 14 at the top surface and the metallized layer 16 of the bottom surface of the photovoltaic device 10 may act as two terminals of the photovoltaic device 10 to establish electrical contacts with other electrical members in an electric circuit.

[0036] Referring to FIG. 2 which illustrates a string 20 (also referred to as 'solar module'). In order to get higher power, a plurality of solar cells 10 are interconnected and assembled in solar modules 20. These solar modules 20 consist of several solar cells 10, which are electrically connected in series. In a solar module 20, the topside metallization of one solar cell 10 may be linked to backside metallization of the next solar cell 10, using ribbons 22 (also referred to as 'tabs'). These ribbons 22 usually made of metal and are soldered on the bus bars 14 of the solar cells 10 in order to minimize contact resistivity and to get a uniform electrical contact over the whole bus bar 14.

[0037] Referring to FIG. 3 which illustrates the spring probe approach 30 of electrical contacting with the bus bars 14 of a photovoltaic device 10 according to the state of the art. The spring probe approach 30 may includes a plurality of spring probes 32 consisting of needle pins guided in a tube and preloaded by springs. For contacting the bus bar 14 of the solar cell 10, an array of the plurality of spring probes 32 may be aligned over the bus bar 14 and may be fixed on a fixation bar 34. The solar cell 10 may be placed over a plate member 36 for electrical contact with the metallization layer 16 on the bottom surface of the solar cell 10. The plate member 36 may have contacting means that may be contact needles or the plate member itself.

[0038] Referring to FIG. 4 which illustrates a bent wire approach 40 of electrical contacting with the bus bars 14 of the photovoltaic device 10, according to the state of the art. A plurality of bent metallic wires 42 may be used for electrical contact with the bus bar 14 of the photovoltaic device 10. One end of the bent wire 42 may be connected to the bus bar 14 and may be aligned over it. The other end may be fixed outside the photovoltaic device 10 areas to atleast a fixture 44 which may be then connected to electrical terminals of a photovoltaic testing apparatus. The bent wires 42 are aligned in a way to minimize the cast shadows on the photovoltaic device 10. The photovoltaic device 10 may be placed over the plate member 36 for electrical contact with the metallization layer 16 on the bottom surface of the photovoltaic device 10.

[0039] Referring to FIG. 5 which illustrates a system 50 for making atleast a detachable electrical contact with atleast a bus bar 14 of atleast a photovoltaic device 10, according to an exemplary embodiment of the present invention. The system 50 comprises atleast a support member 52 and a plurality of contact members 54 protruding from the support member 52 towards the bus bar 14. The contact members 54 may contact the bus bar 14 (as shown in FIG. 5). The contact members 54 also may not contact the bus bar 14 (as shown in FIG. 5A). The contact members 54 may incline at an angle from a face of the support member 52. The contact members 54 may be adapted to make atleast the detachable electrical contact with the bus bar 14 (also referred to as 'contact area') of the photovoltaic device 10. The contact members 54 may have any shape with a portion extending perpendicular to the support member 52. These contact members 54 may be arranged in a single row and are held together by the support member 52. They may align along the bus bars 14 and get in contact with the latter in order to assure electric contact. [0040] The contact members 54 may be bent within their elastic deformation range thus preventing permanent deformation, maintaining their high precision. Since only deformation of the contact members 54 determines the force exerted on photovoltaic device 10 and may not have play, such systems may not suffer from tiring and aging of the material due to friction and galling. The photovoltaic device 10 may be put at the plate member 36. According to an exemplary embodiment of the present invention, in the plate member 36 another electrical contacting systems may be integrated.

[0041] The contact members 54 may be created by two dimensional machining of the plate member 36. This permits the construction of integrated, complex deformable systems at low cost parts. Several movable sub-parts, for example, restrict degrees of freedom to prevent damage to the contact area 14 or photovoltaic device 10 may be integrated in one single main piece without demanding additional assembly steps. The contact members 54 may have different sizes to ensure good contact and cushion the electrical contact of the photovoltaic device 10. It may be expected that pressure in the middle portion of the photovoltaic device 10 may be less because the support member 52 may bent in upward direction from the middle. Therefore the contact members 54 near the middle portion of the photovoltaic device 10 may extend further or at a wider /steeper angle from the support member 52. Further, a support member may also be adapted which is pre- shaped (U-shaped) and gets in a perfectly horizontal alignment, when all contact members 54 are in contact.

[0042] The support member 52 holds together the contact members 54 and may be aligned over the bus bar 14. The support member 52 may collect the electric current of the contact members 54 and conducts it to one single contact point. It may be designed with a low height in order to reduce shadowing effects on the photovoltaic device 10. In the middle or anywhere on the support member 52, a space may be left free in order to fix atleast an electric voltage contact 202, which may be electrically isolated from the rest of the surface of the support member 52. This is necessary to perform the voltage measurement to obtain the IV- curve. Further, for metrological accuracy more than one tension contact, distributed over the support member 50, may also be adapted.

[0043] In an exemplary embodiment of the present invention, the system 50 may further comprise a plurality of suspension units 56. Each suspension unit 56 may be provided at the end of the support member

52. The suspension unit 56 may also be attached to a frame member 63. The frame member 63 may be extending around atleast one of the plate member 36 and the photovoltaic device 10 to hold multiple holding members 57 (as shown in FIG. 9A). The frame member 63 may move with respect to atleast one of the plate member 36 and photovoltaic device 10 to facilitate contact of the contact member 54 with the photovoltaic device 10. The suspension units 56 may be adapted to hold the support member 52 on the photovoltaic device 10, such that the suspension units 56 may allow the support member 52 to move with respect to the suspension units 56. The suspension units 56 may be part of the support member 52.

[0044] In an exemplary embodiment of the present invention, each suspension unit 56 may comprise atleast a holding member 57 and atleast a horizontal member 58. The horizontal members 58 may connect atleast the holding member 57 to the support member 52 in such manner that the plurality of horizontal members 58 may allow vertical movement of the support member 52 with respect to the suspension units 56.

[0045] Referring to FIG. 5A, the holding members 57 may be attached to the frame member 63 that may be extending around the photovoltaic device 10, according to an exemplary embodiment of the present invention. The holding members 57 may be movable relative to the photovoltaic device 10. The frame member 63 may be pivot around pivoting means 66 over an axis extending perpendicular to the plane of the FIG. 5A. The suspension unit 56 may be rotatably attached to a base member 61 so that the suspension unit 56 may rotate about a joint member 65. The frame member 63 extending around the photovoltaic device 10 is capable of controlling the movement of the holding member 57 (on the left of the FIG. 5A) in such a way so that the holding member 57 may not move too far in the direction of the photovoltaic device 10.

[0046] In the embodiment shown in FIG. 5A, atleast the holding member 57 may be electrically isolated from the base member 61 by atleast an isolator 200. An ampere meter 201 may be adapted to measure the current generated by the photovoltaic device 10 under test. Atleast a separate pin member 202 (as shown in FIGS 5A) isolated by isolators (not shown) from the support member 52 may be adapted to measure the voltage generated by the photovoltaic device 10 by means of voltmeter 205.

[0047] In another exemplary embodiment of the present invention, the suspension unit 56 may pivot around atleast one of the pivoting means 66 the holding member 57 (which may be held by the base member 61) while the other holding member 57 may prevent the support member 52 from coming too close to the surface of the photovoltaic device 10. The holding members 57 for multiple bus bars 14 may be connected for ease of handling.

[0048] In another exemplary embodiment of the invention, the photovoltaic device 10 on the plate member 36 may move towards the holding members 57 in order to establish electric contact of the bus bars 14 with the contact members 54. [0049] According to an exemplary embodiment of the present invention, the plate member 36 may be fixed and the contact members 54 may be movable to establish electric contact with the bus bars 14.

[0050] Atleast one of the holding members 57 may be rotatably connected to atleast one of the frame member 63 and the base member 61 to facilitate the movement of the suspension unit 56.

[0051] The horizontal members 58 may allows vertical translation of the holding members 57 relative to the support member 52 and block all other translation. If the contact is closed with too much force or speed, the horizontal members 58 may prevent the force exerted on the photovoltaic device 10 from becoming too large.

[0052] In an exemplary embodiment of the present invention, each suspension unit 56 further comprises a delimiter 59, such that the plurality of horizontal members 58 may be connected to the support member 52 from the delimiter 59.

[0053] Referring to FIG. 6 which illustrates the delimiter 59, according to an exemplary embodiment of the present invention. The vertical movement range of the support member 52 may be defined by the space between the delimiter 59 and the holding members 57. The vertical movement of the support member 52 may be restricted by the delimiters 59 in order to not pass the elastic limits of the vertical guiding members. The delimiter 59 may limit the vertical movement of the support member 52 with respect to the suspension units 56.

[0054] In order to increase movement range of the suspension units 56, the initial vertical position of the support member 52 may be forced toward the photovoltaic device 10 by the use of preloading springs or by pre-stressing the horizontal members 58.

[0055] In an exemplary embodiment of the present invention, the plurality of contact members 54 includes atleast a shock absorbing member 55 (as shown in FIGS. 5 to 7). The shock absorbing member 55 may be adapted to absorb shock when atleast one of the horizontal members 58, support member 52, contact members 54 or any combination thereof may move towards the photovoltaic device 10 to make the electrical contact. The shock absorbing member 55 preferably does not make any contact with the photovoltaic device 10. The shock absorbing member 55 may abut on isolating members 203 (as shown in FIG. 5 A). [0056] In another exemplary embodiment of the present invention, each of the shock absorbing members 55 may be located at the end of the support member 52, such that the plurality of contact members 54 may be in between the pair of shock absorbing members 55. The shock absorbing members 55 may rest on the plate member 36 when the contact members 54 approach the photovoltaic device 10, thus preventing the electrical contacts from hitting the photovoltaic device 10 with too high speed or force. The shock absorbing members 55 may be adapted not to rest or touch the photovoltaic device 10 to prevent the photovoltaic device 10 from a possible damage from the shock absorbing members 55.

[0057] The shock absorbing members 55 may be the first part of the system 50 that comes in contact with the isolating members 203. Before any of the contact members 54 gets in contact with the photovoltaic device 10, the shock absorbing members 55 may hit on the plate member 36 and may be bent. The deformation energy to bend the shock absorbing members 55 may absorb a certain amount of kinetic energy of the support member 52 and may reduces the shocks between the contact members 54 and the fragile photovoltaic device 10.

[0058] If the plate member 36 may be made of conductive material which may in contact with the metallization layer 16 on back side of the photovoltaic device 10 (as shown in FIG. 1), an additional isolation layer may be placed between the plate member 36 and the absorbing members 55.

[0059] Referring to FIG. 7 which illustrates a plurality of stoppers 65, according to another exemplary embodiment of the present invention. The system 50 further includes a plurality of stoppers 65 associated with the plurality of contact members 54 between the contact members 54 and the support member 52. The stoppers 65 may be extended from the support member 52 and may prevent the contact members 54 from bending beyond their elastic deformation range when the system 50 moves towards the photovoltaic device 10 to make the electrical contact with the bus bar 14 of the photovoltaic device 10 that is placed on the plate member 36.

[0060] Referring to FIG. 8 which illustrates the headed contacts on the contact members 54, according to an exemplary embodiment of the present invention. The plurality of contact members 54 may be provided with bulges 68 for better electrical contact with the bus bar 14 of the photovoltaic device 10 placed on the plate member 36. [0061] Every contact member 54 may be made of a single flexible blade. To make the contact with the photovoltaic device 10, these members may be slightly deformed to increase the contact force. At the tip of each of these contacting members 54 bulges 68 may be added in order to better define the location and surface of the electric contact and to provide wearing material to increase the contact's lifetime. The contact location, surface of the electric contact and the wear of the contacting member 54, all influence the contact resistance with the photovoltaic device 10. By using bulges 68 of the contact member 54, the wear does not change the location nor the contact surface, thus keeping the contact resistance constant thereby improving the reliability of the measurements.

[0062] In an exemplary embodiment of the present invention, the support member 52 and the plurality of contact members 54 may be formed from a single piece of material. This makes the system 50 easy to manufacture and needs no assembling since it consists of one piece. It has no parts that exert friction and therefore no wear and thus no play. The shape and number of contact members 54 may be chosen freely to make the contact more similar to that of the ribbon 18 or atleast establish a contact that is constant over time and does not change too much with the number of measurements.

[0063] In an exemplary embodiment of the present invention, the support member 52 may be aligned over the bus bar 14.

[0064] In an exemplary embodiment of the present invention, the width of the contact members 54 may be less than the width of the bus bar 14 of the photovoltaic device 10. In another exemplary embodiment of the present invention the width of the contact members 54 may be equal to the width of the bus bar 14 of the photovoltaic device 10. By making the width of the contact members 54 less wide than the bus bar 14 and also reducing its height prevents shadows from being cast onto the active area of the photovoltaic device 10.

[0065] In another exemplary embodiment of the invention, the width of any one of the support member 52 and the contact members 54 may be slightly larger than the bus bar 14 to allow constant shadowing on the photovoltaic device 10 even in the case of positioning tolerances. As long as the support member 52 protrudes on both sides of the bus bar 14, the shaded area may be known. Knowing how much shadow falls onto the photovoltaic device 10, may be compensated electronically.

[0066] In an exemplary embodiment of the present invention, surfaces of the system 50 may be colored, for example, black, and have a rough structure to avoid light reflections. [0067] In an exemplary embodiment of the present invention, the system 50 may be made of atleast a conductive material. The conductive material may be selected from a list of materials comprising CuNi25Znl2, CuNi25Zn8, CuNi25Znl7, CuNi45, Copper, Nickel, Zinc, Magnesium, plastic with conductive material addition or any combination thereof. If plastic is used, it may be metalized afterwards.

[0068] In an exemplary embodiment of the present invention, the system 50 may be manufactured by atleast one manufacturing process from a list of casting, extruding, molding, machine cutting by using laser, water beam, wire saw, electrical discharge machining, lapping, milling, wire-electro erosion, chemical machining, drilling, conventional mechanical machining or any combination thereof.

[0069] Referring to FIG. 9A which illustrates an apparatus 100 for testing a photovoltaic device 10, according to an exemplary embodiment of the present invention. The apparatus 100 comprises atleast the photovoltaic device 10, atleast the system 50 (as shown in FIGS 5 and 5 A) for making atleast a detachable first electrical contact with atleast the bus bar 14 on the top side of atleast the photovoltaic device 10, and a plate member 36 to make a second electrical contact with the bottom side of atleast the photovoltaic device 10, such that the first electrical contact and the second electrical contact may connect the photovoltaic device 10 to a current measurement means to test the photovoltaic device 10. According to an exemplary embodiment of the present invention, the plate member 36 may be replaced by any one of the system 50 and apparatus 100 of the present invention.

[0070] In an exemplary embodiment of the present invention, a method for making atleast the detachable electrical contact with atleast the bus bar 14 of atleast the photovoltaic device 10, to facilitate testing of the photovoltaic device 10 may comprises the steps of: pressing the system 50 onto the surface of the photovoltaic device 10 such that the contact members 54 of the system 50 make electrical contact with all of top surface of the bus bar 14 or a contact area of the photovoltaic device 10.

[0071] Knowing the rigidity of the horizontal members 58 and of the contact members 54, the contact force may be measured and regulated by the use of a single distance sensor. This sensor may measure the distance between the horizontal members 58 and the moving support member 52. The sensor may be optical, mechanical, acoustic or other type. Alternatively, strain gauges may be attached to the horizontal members 58 or support member 52 in order to measure their deformation. [0072] The arrangement of the contact members 54 may be very flexible and may be redesigned and adapted to almost any photovoltaic device 10 design. A screw may be used to change the distance between certain elements thus changing the allowed movement or force of the contact.

[0073] In an exemplary embodiment of the present invention, for the electrical contacting of the bottom side of the photovoltaic device 10, a system (possible static) similar to the system 50 may be used. Flexible contact members 54 may be integrated with the plate member 36, which get in contact with the bottom side metallization layer 16 (FIG. 1) of the photovoltaic device 10. For holding a suction head or magnet may be integrated in the plate member 36 and may be combined with the system 50 to firmly hold the photovoltaic device 10.

[0074] The system 50 may be used for a sun simulator for a single solar cell 10. It may also be used to contact atleast one solar cell 10 of a string 20. It may be used in any device such as a stringer, wafer or cell testing device or production facility. The system 50 may be primarily used for picking up the current from the solar cell 10. For normal testing of solar cells 10, an IV-curve, current as function of voltage may be measured.

[0075] For the IV measurement, an additional contact 202 (FIG. 5A) may be integrated for measuring the voltage. Since this measurement may be done almost without drawing a current, the contact does not have to be as good as with for the current measurement. A wire member 205 may be glued to the upper side of the support member 52 and the wire reaches the solar cell 10 by means of an opening in the support member 52 at the centre.

[0076] In various exemplary embodiments of the present invention, the operations discussed herein, e.g., with reference to FIGS. 1 to 9 A, may be implemented through computing devices such as hardware, software, firmware, or combinations thereof, which may be provided as a computer program product, e.g., including a machine-readable or computer-readable medium having stored thereon instructions or software procedures used to program a computer to perform a process discussed herein. The machine-readable medium may include a storage device. For example, the operation of components of the system 50 and apparatus 100 may be controlled by such machine-readable medium.

[0077] In other instances, well-known methods, procedures, components, and circuits have not been described herein so as not to obscure the particular embodiments of the present invention. Further, various aspects of embodiments of the present invention may be performed using various means, such as integrated semiconductor circuits, computer-readable instructions organized into one or more programs, or some combination of hardware and software.

[0078] Although a particular exemplary embodiment of the invention has been disclosed in detail for illustrative purposes, it will be recognized to those skilled in the art that variations or modifications of the disclosed invention, including the rearrangement in the configurations of the parts, changes in sizes and dimensions, variances in terms of shape may be possible. Accordingly, the invention is intended to embrace all such alternatives, modifications and variations as may fall within the spirit and scope of the present invention.

[0079] The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions, substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but is intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention.

Claims

CLAIMS We Claim:

1. A system for making atleast a detachable electrical contact with atleast a photovoltaic device, comprising:

atleast a support member; and

a plurality of contact members adapted to establish the detachable electrical contact with atleast the photovoltaic device,

wherein a single piece of a material is adapted to form the support member and the contact members.

2. The system according to previous claim, wherein atleast a suspension unit is adapted to allow movement and rotation of the support member, wherein the suspension unit is formed from said single pieceof said material.

3. The system according to previous claims, wherein the suspension unit comprising atleast a holding member and atleast a horizontal member, wherein the horizontal member is adapted to allow vertical movement of the support member with respect to atleast the holding member.

4. The system according to previous claims, further comprising atleast a delimiter adapted to limit the vertical movement of the support member with respect to the holding means.

5. The system according to previous claims, wherein a plurality of shock absorbing members are adapted to absorb shock when the system is moved towards the photovoltaic device to make the electrical contact with the photovoltaic device.

6. The system according to previous claims, wherein a plurality of stoppers associated with the plurality of contact members to prevent the contact members from bending beyond their elastic deformation range.

7. The system according to previous claims, wherein each contacting member having atleast a bulge for electrical contact with the photovoltaic device.

8. The system according to previous claims, wherein the support member is aligned over atleast a contact area of the photovoltaic device.

9. The system according to previous claims, wherein a width of the plurality of contact members is less than or equal to the width of the bus bar of the photovoltaic device.

10. The system according to previous claims, wherein the material includes atleast one conductive material from a list of materials comprising CuNi25Znl2, CuNi25Zn8, CuNi25Znl7, CuNi45, Copper, Nickel, Zinc, Magnesium, plastic with conductive material addition or any combination thereof.

11. The system according to previous claims, wherein the system is manufactured by atleast one manufacturing process from a list of casting, extruding, moulding, machine cutting by using laser, water member, wire saw, electrical discharge machining, lapping, milling, wire-electro erosion, chemical machining, drilling, conventional mechanical machining or a combination thereof.

12. The system according to previous claims, wherein atleast one of the delimiter, the horizontal member and the shock absorbing members or any combination thereof is made from said single piece of said material.

13. An apparatus for testing atleast a photovoltaic device, comprising:

Atleast the photovoltaic device having a top side with an electrical contact and a bottom side with an electrical contact;

atleast a system for making atleast a detachable first electrical contact with atleast a contact area on the top side of the photovoltaic device, comprising atleast a support member and a plurality of contact members protruding towards the contact area and inclined at an angle from the face of the support member, such that the plurality of contact members are adapted to make atleast the detachable first electrical contact with the contact area on the top side of the photovoltaic device; and

atleast a ground plate with contact means to make atleast a second electrical contact with the bottom side of the photovoltaic device, such that the first electrical contact and the second electrical contact connect the photovoltaic device to a current measurement means to test the photovoltaic device.

14. The apparatus according to previous claims, further comprising means for measuring the voltage of the contacts area of the photovoltaic device.

15. A method for making atleast a detachable electrical contact with atleast a contact of atleast a photovoltaic device, to facilitate testing of the solar cell using the apparatus according to claim 13.