Test element for solar cells

Abstract

The present invention relates to a test element (10) for disconnectable electrical contacting of an electrically conductive substrate, in particular of a busbar-less solar cell, having two preferably slat-shaped mounting rails (1a, 1b) with at least one slat-shaped test rail (2) arranged therebetween, which has a main body (2a) and a plurality of contact elements (2c) formed integrally with the main body and arranged on one side thereof.

Description

[0001] Test element for solar cells

[0002] The present invention relates to a test element for testing busbarless or busbarless solar cells, in particular for detachably contacting finger electrodes of the solar cell.

[0003] Devices and correspondingly designed measuring or test elements for detachably electrically contacting a solar cell for testing purposes are known from the prior art. In particular, it is known to electrically contact busbars arranged on the solar cell by applying pressure. By simultaneously applying light and performing a current and / or voltage measurement using the corresponding test device having one or more measuring or test elements, a test and thus a qualitative assessment of the solar cell can be carried out. More innovative solar cells have a busbar-free design in which only the finger electrodes or so-called "cell fingers" arranged in parallel on the solar cell are present.Such solar cells enable the achievement of a higher efficiency through less shading while simultaneously saving silver and only have the aforementioned finger electrodes arranged in parallel at predefined intervals for a possible test tap.

[0004] DE 10 2008 038 184 A1 describes a method and a device for temporarily electrically contacting a solar cell for testing purposes. The test probe has a plurality of pointed contact elements arranged comb-like on a rail for scratching a busbar of the solar cell. A centrally arranged protrusion of the contact elements in a plane outside the rail is intended to provide a spring effect. However, the specific design of the test rail does not allow for reliable contact, particularly with finger electrodes of a busbarless solar cell. Furthermore, the design of the protrusions leads to partial shading of the solar cell during the testing process, which can impair the test result.

[0005] WO 2012 / 095275 describes a one-piece test rail for electrically contacting a solar cell busbar, comprising a plurality of tapered contact fingers extending substantially perpendicular to a longitudinal direction of the test rail. A bending element extending laterally from a linear extension of the contact fingers in the longitudinal direction of the test rail is intended to provide a spring effect in the longitudinal direction of the contact fingers.

[0006] DE 10 2018 132 451 A1 describes a test rail for busbarless solar cells comprising a thin-walled main body, a plurality of contact elements connected thereto, and spring elements arranged therebetween. The spring elements each comprise two parallel and angled wire elements arranged on either side of the respective contact element and inclined perpendicular to the plane of the main body.

[0007] WO 2019 / 154464 A1 describes a test rail for busbarless solar cells, comprising a rail-like main body and a plurality of loop-shaped or hook-shaped contact spring sections extending therefrom. The hook-shaped configuration described therein promotes undesirable tilting of the contact sections on the finger electrodes of the solar cell to be tested. The loop-shaped configuration described therein leads to significant limitations with regard to the necessary stroke during testing of the solar cell and with regard to the alignment of adjacent contact sections in the longitudinal direction of the rail due to their tendency to touch. In particular, the loop-shaped configuration shown leads to a significant tendency of the contact sections to tilt and bend, thus impairing the contact quality and test accuracy.

[0008] DE 10 2020 109 119 A1 discloses a test rail for contacting a busbarless solar cell, comprising an elongated, lamellar base body with a plurality of contact elements arranged on one side and formed integrally with the base body. The contact elements each have a linear contacting section arranged at one end, which extends with a predefined length parallel to a longitudinal direction of the base body. The test rail is suspended in a support frame of a test system by means of two retaining pins arranged opposite one another at the ends, thereby holding it in position.

[0009] A disadvantage of the known prior art is that the test rails and the test elements or test devices comprising them are easily bendable due to their preferably small thickness due to shading problems in the context of solar cell testing. When mounted in a test system, they usually have to be tensioned longitudinally in a correspondingly designed support frame in order to ensure a certain level of stability for a reliable testing process. The necessary holding device is structurally complex and complicates the installation and replacement of individual test rails. In particular, a support frame of the test system must be designed to be more solid or stable for tensioning, whereby the relatively high mass must be accelerated and decelerated to execute a lifting movement during the testing process for each contact with the solar cells.This places greater demands on the drive, making it more difficult to minimize the cycle time for contacting during the testing process, a key parameter. Furthermore, the thickness of the test rail or any test fixture surrounding it should be kept as low as possible to minimize shading of a solar cell during testing.

[0010] Based on the known prior art, the object of the present invention is to provide an improved test element for testing solar cells, in particular for testing busbarless solar cells, which addresses the aforementioned disadvantages of the prior art. In particular, this element should enable a simple design and optimized handling and arrangement in a test system, in addition to high contact quality and high test quality.

[0011] This object is achieved by a test element according to the independent claims. The dependent claims describe advantageous developments of the present invention.

[0012] In a first aspect, the present invention relates to a test element for the detachable electrical contacting of an electrically conductive substrate, in particular a busbarless solar cell, comprising two preferably lamellar support rails with at least one lamellar test rail arranged therebetween, comprising a base body and a plurality of contact elements arranged on one side thereof and formed integrally with the base body, wherein at least one of the opposing inner surfaces of the support rails has a structured surface designed to interact with the test rail, and that the inner surfaces form contact surfaces aligned with one another, which are connected to one another, preferably by means of a material bond, by means of intermediate connecting and / or insulating means.The inventive design of the test element enables a significant increase in the rigidity of the test element through the combination of a structured surface and the formed contact surfaces, which are connected to one another by means of intermediate connecting and / or insulating means. The particularly material-to-material connection by means of appropriately designed contact surfaces of the two support rails achieves increased rigidity against bending of the test element, thereby facilitating the handling of the test element and, in particular, its arrangement in a test system. The more stable design of the test element, in particular, eliminates the need for bracing the element in a test system using separately provided clamping devices.Contrary to the prior art, the test element according to the invention can therefore simply be suspended in a corresponding fixture, i.e., without applying a longitudinal clamping force to both ends of the test element. Alternatively, the test element can also be screwed or tightened in a corresponding fixture without longitudinal clamping force. At the same time, a structurally simple, easy-to-manufacture, and minimally thick design of the test element is achieved.

[0013] In the present case, a structured surface is understood to mean that the surface has a structure in the form of at least one, preferably several, projections and / or recesses in an otherwise preferably flat surface.

[0014] In a preferred embodiment, the structured surface forms at least one internal recess, which is designed to at least partially accommodate and, more preferably, to securely support the test rail. This allows the test rail to be at least partially accommodated or inserted into the internal recess, which can be formed, for example, as a flat recess in the surface.

[0015] The structured surface further advantageously forms an inner contour which, in particular in a side view of the test element, is adapted to an outer contour of the test rail. As a result, the test rail can be arranged or inserted in or on the inner structure of the surface in a predefined position. The inner contour surrounds the outer contour of the test rail, preferably on at least two, more preferably on three adjacent sides of the test rail, preferably on an upper edge and two side edges arranged laterally thereto. The test rail preferably lies directly on at least one, more preferably on at least two sides of the test rail. Further alternatively, the test rail can be inserted with a slight play or tolerance in the inner contour of the support rail.

[0016] More preferably, the inner recess forms a depth or comprises a predefined depth, which is designed such that the test rail, with a side surface facing away from the recess, is arranged flush with a remaining inner surface surrounding the inner recess. The remaining inner surface surrounding the inner recess is preferably flat. Alternatively, the depth of the inner recess can be designed such that the test rail protrudes slightly from the inner surface surrounding the recess, such that, when the components of the test element are connected, there is a press fit of the test rail in the support rails.

[0017] In a preferred embodiment, the structured surface forms and / or encompasses a support element. The support element preferably has at least one contact stop, advantageously extending in the longitudinal direction of the test element, for an upper edge of the test rail arranged opposite the contact elements of the test rail. This protects the upper edge of the test rail against bending and / or deformation, particularly during a contacting process of the contact elements. In a particularly preferred embodiment, the support element is formed in a lower edge of an inner recess of the support rail, aligned with the test rail.

[0018] Alternatively or additionally, an upper edge of the test rail can have at least one or more support or bearing elements arranged therein, in particular in sections, which are designed to bear against the structured surface and / or a support element of the structured surface of the support rails. The support or bearing elements can be designed in particular to bear against a continuous inner edge in the longitudinal direction of the structured surface of the support rails. Further advantageously, at least one of the support rails, preferably both support rails, can have one or more elongated recesses, for example in the form of an elongated hole, which are preferably arranged in sections in the longitudinal direction and in the region of a respective support or bearing element of the test rail.This allows for optimized installation and / or alignment between the test rail and the support rails.

[0019] In a preferred embodiment, the connecting and / or insulating means comprise a preferably insulating film element arranged between the support rails or an insulating rail with adhesive surfaces preferably arranged on both sides and / or formed thereon. The film element preferably comprises an outer contour substantially corresponding to the support rails. The adhesive surfaces arranged on both sides are further advantageously arranged only in one region of the base body of the test rail, i.e. not in the region of the contact elements. The film element and the support rails are preferably arranged and / or formed such that the opposite contact surfaces of the support rails rest directly on the film element on both sides, in particular without intermediate layers, and particularly preferably without an intermediate test rail.The foil element serves to provide a direct and material-to-material connection between the opposing support rails. This creates a stable connection between the two outer support rails and thus increases the rigidity of the test element.

[0020] In a further preferred embodiment, the connecting and / or insulating means comprise at least one, preferably a plurality of, adhesive reservoirs formed in the support rails and / or in the test rail and preferably open to the outside. The adhesive reservoirs can be formed at least partially by the structured surfaces of the opposing inner surfaces of the support rails. The adhesive reservoirs can also be formed at least partially by recesses in an upper edge of the test rail.

[0021] Further preferably, the adhesive reservoirs are arranged distributed in the longitudinal direction of the test element. In particular, the reservoirs can be arranged distributed at predefined constant intervals in the longitudinal direction. The adhesive reservoirs can further advantageously have an opening directed outwards and in particular towards an upper edge of the test element for filling the reservoirs. This allows the test element and in particular the test rail and the support rails to be first assembled and then an adhesive to be filled into the reservoirs and cured. The adhesive reservoirs are further advantageously designed such that an adhesive to be filled can be filled into the reservoirs by gravity and / or by capillary action.

[0022] In a further preferred embodiment, the connecting and / or insulating means comprise at least one, preferably a plurality of through-openings formed in the test rails and filled with adhesive. The through-openings can be filled with adhesive during assembly of the test element and in particular after insertion of the test rail into one of the support rails, with the remaining components, and in particular the second support rail, subsequently being attached. The through-openings are advantageously arranged distributed in the longitudinal direction of the test element or the test rail. The through-openings advantageously have a flat design such that a longitudinal extent or a radius of the through-opening is greater than a depth of the through-opening perpendicular to the longitudinal extent.This provides at least a surface contact by the connecting and / or insulating means and in particular a surface wetting or adhesion.

[0023] The aligned contact surfaces, which are connected to one another by means of the connecting and / or insulating means, preferably each comprise a flat surface. The contact surfaces are more preferably designed as surfaces arranged parallel to one another. In a particularly preferred embodiment, the aligned contact surfaces are connected only by means of the intermediate connecting and / or insulating means, wherein no further intermediate layer or element, in particular no section of the test rail, is arranged at the respective connection points. The contact surfaces can each be formed by an inner surface of the support rails that at least partially surrounds the test rail.The contact surfaces may further comprise a plurality of surface sections of the inner surfaces of the support rails that are aligned with one another and distributed in the longitudinal direction of the test element.

[0024] The two support rails preferably each comprise a flat outer surface. In a preferred embodiment, the support rails have a substantially identical outer contour. Further preferably, the test rail has a substantially identical outer contour to the support rails. The test rail preferably comprises two opposing side surfaces, which are flat or planar and, more preferably, arranged parallel to one another.

[0025] The test bar is preferably integral, i.e., formed in one piece. The test bar is made of electrically conductive material, in particular metal. The test bar is preferably formed of a metal sheet, with the base body and the contact elements being etched, punched, or cut from a single piece, preferably in a single processing step. In a particularly preferred embodiment, the test bar is made of copper beryllium (CuBe) or a copper-beryllium alloy.

[0026] The test rail can optionally be coated or finished with a conductive material. The coating can, for example, comprise a gold alloy, silver alloy, nickel alloy, or the like. The coating is preferably applied using a galvanic manufacturing process. Particularly preferably, the test rail is galvanically finished with a gold alloy. The coating can be applied to the test rail completely or only partially, in particular coating only the contact elements. In an alternative embodiment, the test rail can be made of non-conductive material, in particular plastic material, and can be at least partially and preferably completely coated with conductive material. The coating can be formed by a conductive paint or cold liquid metal applied to the non-conductive material.

[0027] The respective contact elements of the test rail are preferably arranged equidistant from one another in the longitudinal direction of the base body. In particular, the contact sections are aligned with one another in such a way that the distance between adjacent contact sections is constant.

[0028] The contact elements of the test rail are preferably arranged on the base body of the test rail by means of a respective spring element. The base body, the spring elements, and the contact elements arranged thereon are preferably formed as a single piece. The contact elements have a preferably linear contacting section. This is further advantageously designed in a lamellar manner and has a linear support surface facing away from the base body for contacting the electrically conductive substrate, in particular for contacting preferably two and more preferably three finger electrodes of a solar cell that run parallel and are preferably arranged perpendicular to the contacting section. The support surface is particularly preferably designed for contacting two or three parallel finger electrodes of a solar cell.

[0029] The contact elements preferably have a length L1 of 2.5 to 3 mm, more preferably of 2.7 to 2.9 mm. The respective contacting sections are preferably arranged such that a distance between adjacent contacting sections in the longitudinal direction of extent is less than 0.4 mm, more preferably less than 0.2 mm. The contact elements have, in particular at an end region of the contacting section, a guide element extending essentially perpendicular to the contacting section. This guide element preferably extends over a predefined length and essentially perpendicular to the longitudinal direction of the contacting section such that even when the respective contact element is not in contact, the guide element and thus the contacting section connected thereto runs at least partially within the two opposing support rails of the test element or is guided between them.This provides guidance for the contact element, which in particular prevents twisting of the individual contact sections when contacting a solar cell.

[0030] The test rail preferably has a homogeneous or uniform thickness of 0.1 to 0.25 mm, more preferably of 0.12 to 0.18 mm.

[0031] In a further preferred embodiment, the test element comprises at least a second and / or third test bar, the latter being arranged electrically separated from the first test bar by an insulating bar and / or the connecting and / or insulating means. A voltage measurement can be performed using the first test bar, and a current measurement can be performed using the second and optionally third test bars arranged separately. The insulating bar is advantageously designed as a connecting and / or insulating means as described above.

[0032] The test element further advantageously comprises connecting means arranged at two opposite ends for connection to a test device or a test system and / or for electrically contacting the test element. The connecting means can each comprise mounting holes arranged at the end, which can serve for connection to a test device. In particular, these can be designed for the respective arrangement of a connecting element, which then serves for contacting and / or holding the test element. The respective connecting element is preferably designed to provide galvanic or electrical isolation from a support frame of the test device.

[0033] In a preferred embodiment, the connecting means of the support rails comprise recesses or mounting holes at the two opposite ends, which, when viewed from the side of the test element, are larger than the correspondingly arranged recesses of the at least one test rail of the test element. The recesses, designed, for example, as elongated holes, are designed and arranged such that a surface of the intermediate test rail is exposed at them in a side view. In this way, an electrical conductor for electrically contacting the surface of the test rail can be guided to the respective test rail via the recesses in the support rails and contacted with it.

[0034] The connecting elements for the test element further preferably comprise guide and / or clamping elements, for example in the form of a conductor channel that can be at least partially clamped and by means of which a respective electrical conductor can be arranged in an electrically conductive manner with a surface of the respective test rail^). The respective connecting element is preferably designed in the form of a clamp that can be arranged and / or pushed onto the test element, in which an integrated conductor channel for contacting the test element by means of a respective electrical conductor or a conductor element is further preferably arranged on both sides. The respective connecting element is further preferably designed to be connected to associated mounting means, preferably comprising a carrier element and an associated fastening pin or fastening bolt, in order to be arranged or mounted on the carrier frame of the test device with the aid of these.The fastening pin is preferably mounted in a mounting hole of the support element or screwed to it and, when mounted, penetrates the mounting holes of the test element. The fastening pin can be used to compress or clamp the electrical conductor elements in the conductor channels of the connecting element.

[0035] A respective support element is preferably arranged at the two opposite ends of the test element and arranged in corresponding recesses of a support frame and / or connected to them. The test element is thus held in the support frame of a testing device, preferably without any tensile stress being applied thereto. The support elements are preferably connected to the support frame in such a way that they do not impose any tensile stress on the test element in the longitudinal direction. Alternatively, the support elements can be arranged in the support frame of the testing device so that they are at least partially movable in the longitudinal direction of the test element, so that no tensile stress is applied to the test element in the longitudinal direction.

[0036] In a further aspect, the invention relates to the use of the test element as described above for testing a busbarless solar cell, in particular for measuring current and / or voltage, by electrically contacting finger electrodes arranged parallel on the solar cell surface and preferably with simultaneous exposure of the solar cell to light. In particular, the test bar can be used to measure the efficiency of the busbarless solar cell. Details, further advantageous effects, and details of the present invention are explained below with reference to the purely schematic, merely exemplary drawings.

[0037] Showing:

[0038] Fig.1a: a perspective side view of a preferred embodiment of the test element according to the invention in side view, omitting the second support rail and the connecting and / or insulating means for overview purposes;

[0039] Fig. 1b: a side view of the test element according to Fig. 1a;

[0040] Fig. 1c, d : a respective detailed view of Fig. 1b according to the embodiment of Fig. 1a and a further preferred embodiment;

[0041] Fig. 2: an exploded view of the preferred embodiment of the

[0042] Test element according to Fig. 1 a-1 c;

[0043] Fig. 3: an exploded view of a further preferred embodiment of the test element with three test rails and an intermediate insulating rail as connecting and / or insulating means;

[0044] Fig. 4a-d: a further preferred embodiment of the test rail according to the invention in a lateral sectional view, a detailed sectional view, a perspective detailed view, and an exploded view; Fig. 4e: an exploded view of a further preferred embodiment of the test element according to Fig. 4a-d with three test rails;

[0045] Fig. 5a-d: a further preferred embodiment of the test rail according to the invention in a side sectional view, in a detailed sectional view, in a perspective detailed view and in an exploded view;

[0046] Fig. 6a-f: Side views of preferred embodiments of a respective contact element of the test rail of the test element;

[0047] Fig. 7a-d: a further preferred embodiment of the test rail according to the invention in a side sectional view, in a detailed sectional view, in a perspective detailed view and in an exploded view;

[0048] Fig. 8a: a perspective side view of the holding elements of the

[0049] Test element for connection to a support frame of a test device or test system.

[0050] Fig. 8b: a sectional view of the arrangement according to Fig. 8a;

[0051] Fig. 8c: a perspective side view of a connecting element; and

[0052] Fig. 9: a perspective partial view of a support frame of a

[0053] Testing device. With reference to Figs. 1a-1c and Fig. 2, a first preferred embodiment of the test element 10 according to the invention is described below. The test element 10 has an elongated, lamellar configuration extending along a longitudinal direction L and comprises two preferably lamellar support rails 1a, 1b with at least one lamellar test rail 2 arranged therebetween, wherein only a first support rail 1a is shown in Fig. 1ac for the sake of clarity.

[0054] The test rail 2 comprises a base body 2a and a plurality of contact elements 2c arranged on one side thereof and formed integrally with the base body. The contact elements 2c are arranged on the base body 2a via respective spring elements 2b formed integrally therewith. The contact elements 2c extend substantially perpendicular to the longitudinal direction L. The contact elements 2c are preferably arranged at a uniform distance from one another in the longitudinal direction of the base body 2a.

[0055] The base body 2a of the test rail preferably has a uniform thickness. The base body 2a preferably has projections 13 arranged on both sides of its ends, which can serve to electrically contact the test rail. These projections can, for example, comprise a recess, in particular a bore, which serves for electrical contact by means of a corresponding connecting element.

[0056] The contact elements 2c of the test rail 2 each have a linear contacting section 14 arranged at the end (cf. Fig. 6a-f), which extends in a predefined length L1 parallel to the longitudinal direction L of the base body 2a, such that preferably two, more preferably at least two and a maximum of three, parallel finger electrodes 15 of a solar cell 16 to be tested can be contacted by pressing.

[0057] During the testing process, the finger electrodes 15 are preferably contacted in a direction perpendicular to the parallel arrangement of the finger electrodes (see Fig. 6a).

[0058] Between the base body 2a and the contacting section 14 of the contact element 2c, a spring element 2b is arranged, which extends in a meandering manner and in a plane with the base body 2a and the contacting section 14.

[0059] At least one of the opposing inner surfaces 3a, 3b of the support rails 1a, 1b has a structured surface designed to interact with the test rail 2. The structured surface advantageously forms an inner recess 6 designed to at least partially accommodate and securely support the test rail 2. An inner contour 6a of the inner recess 6 is adapted to an outer contour of the test rail 2 in a lateral view of the test element. The inner recess advantageously has a depth designed such that the test rail 2, with a side surface 7b facing away from the recess 6, is arranged flush with an inner surface 3a surrounding the inner recess 6.

[0060] The structured surface further forms a support element 8 with a contact stop 8a extending in the longitudinal direction L. This is formed on an upper edge 2d of the test rail, arranged opposite the contact elements 2c of the test rail 2, as shown in Fig. 1c. The contact stop 8a can be continuous and, in particular, form a lower edge of the inner recess 6 of the support rail 1a. Alternatively, the support element 8 can comprise a plurality of contact stops 8a distributed in the longitudinal direction, as shown in Fig. 1d.

[0061] The inner surfaces 3a, 3b of the support rails 1a, 1b form aligned contact surfaces 4a, 4b, which are connected to one another, preferably by means of a material bond, by means of intermediate connecting and / or insulating means 5. In the exemplary embodiment according to Fig. 1a-2, the contact surfaces 4a, 4b are formed by the surface of the support rails 1a, 1b surrounding a respective inner recess 6. These contact surfaces bear directly on both sides against the connecting and / or insulating means 5, which in the present exemplary embodiment comprise a lamellar film element 9. This is arranged between the support rails 1a, 1b and has an outer contour corresponding to the support rails 1a, 1b. The film element 9 comprises adhesive surfaces 9a arranged on both sides, which are connected to the contact surfaces 4a, 4b directly adjacent thereto, thereby establishing a material bond.The adhesive surfaces 9a arranged on both sides are contoured to correspond to the adjacent contact surfaces 4a, 4b. The adhesive surfaces are preferably designed such that they do not interact with or adhere to the spring and contact elements 2b, 2c of the test rail 2 that are in contact with the film element 9. Thus, the spring and contact elements 2b, 2c arranged on the base body 2a of the test rail 2 are movably arranged between one of the support rails 1a, 1b and the film element 9 that is in contact with it.

[0062] At opposite ends of the test element 10, a connecting element is provided which comprises a one-piece connecting element 17 (cf. Fig. 2, 4d) or is formed from two pluggable connecting elements 17a, 17b (cf. Fig. 3). The connecting elements can be arranged at two oppositely arranged recesses or mounting holes 21 of the test element and serve in particular to connect the test element 10 to a test device or a holding frame 30 of a test device (cf. Fig. 8).

[0063] Fig. 3 shows a further preferred embodiment of the test element 10, which, in deviation from the embodiment according to Fig. 1 a-2, has a plurality of test rails 2, 2', 2". The additional test rails 2', 2" are preferably arranged in opposite alignment in the longitudinal direction to one another and directly adjacent, preferably in such a way that a continuous contact line is achieved by means of the contacting sections 14 of the contact elements.

[0064] The foil element 9 forms an insulating rail, which electrically insulates the first test rail 2 from the two other test rails 2', 2". This allows a voltage measurement to be carried out using the first test rail 2 and a current measurement to be carried out using the second and third test rails 2', 2".

[0065] Fig. 4a-d show a further preferred embodiment of the test element 10 according to the invention. This corresponds in basic structure to the embodiment according to Fig. 1a-2. Here, the connecting and / or insulating means 5 comprise a plurality of adhesive reservoirs 11 formed in the support rails 1a, 1b and / or in the test rail 2 and preferably open to the outside. These are preferably arranged distributed in the longitudinal direction of the test element 10 and thereby enable an optimized connection of the two support rails 1a, 1b.

[0066] The adhesive reservoirs 11 are formed at least partially by the structured surfaces of the opposing inner surfaces 3a, 3b of the support rails 1a, 1b. Furthermore, the adhesive reservoirs are formed at least partially by structured recesses 11b in an upper edge of the test rail 2. The adhesive reservoirs have an opening 11a directed outward, in particular toward an upper edge of the test element 10, for filling the reservoirs.

[0067] In this embodiment, the aligned contact surfaces 4a, 4b for holding the test element 10 together are formed by opposing surface sections of the adhesive reservoirs 5 in the inner surfaces 3a, 3b of the support rails 1a, 1b. After the individual components of the test element 10 have been assembled, the adhesive reservoirs 11 can be filled with adhesive, which can then be cured.

[0068] Fig. 4e shows a further preferred embodiment of the test element 10, which, in deviation from the embodiment according to Figs. 4a-d, has a plurality of test rails 2, 2', 2", analogous to the embodiment according to Fig. 3. The additional test rails 2', 2" are preferably arranged in opposite alignment to one another in the longitudinal direction and directly adjacent. A lamellar foil element 9 arranged between the test rails 2 and 2', 2" can form an insulating rail, which electrically insulates the first test rail 2 from the two further test rails 2', 2".

[0069] Fig. 5a-5d show a further preferred embodiment of the test element 10 according to the invention. This corresponds in its basic structure to the embodiment according to Fig. 1 ad and Fig. 3. Here, the connecting and / or insulating means 5 comprise a plurality of through openings 12 formed in the test rails 2 and filled with adhesive. These preferably have a flat design such that a longitudinal extent or a radius of the through opening is greater than a depth of the through opening perpendicular to the longitudinal extent.

[0070] In this embodiment, the aligned contact surfaces 4a, 4b for holding the test element 10 together are formed by surface sections in the inner surfaces 3a, 3b of the support rails 1a, 1b that are opposite one another at the through-openings 12. After placing or pre-positioning a support rail 1a, 1b with a test rail 2 adjacent thereto, the through-openings 12 are filled with adhesive before the remaining components are arranged thereon and the adhesive is cured.

[0071] In Fig. 5d, analogous to the embodiment according to Fig. 4a, a configuration with a plurality of test rails 2, 2', 2" is shown. A lamellar foil element 9 arranged between the test rails 2 and 2', 2" can form an insulating rail which electrically insulates the first test rail 2 from the two further test rails 2', 2". The embodiment according to Figs. 5a to 5d can alternatively have only one test rail 2 and two directly adjacent support rails 1a, 1b.

[0072] Fig. 6a-f show preferred embodiments of a contacting section 14 of a respective contact element 2c of the test rail 2. This preferably comprises a guide element 18 projecting upwardly at the end of the linear contacting section 14. This guide element extends at least partially orthogonally to the direction of extension of the linear contacting section 14 and serves in particular to guide the contacting section 14 between the two support elements 1a, 1b resting on the test rail 2 during compression and rebound during contacting of a solar cell S. The guide element can have a variety of different designs, as shown in Fig. 6a-f. Fig. 7a-d show a further preferred embodiment of the test element 10 according to the invention. This corresponds in basic structure to the embodiment according to Fig. 3.

[0073] Deviating from the embodiment according to Fig. 3, an upper edge of the test rail 2 comprises at least one or more support or bearing elements 19 arranged therein, in particular in sections, which are designed to bear against the structured surface, in particular a support element 8 of the structured surface of the support rails 1a, 1b, preferably in the form of a continuous inner edge in the longitudinal direction. At least one and preferably both support rails 1a, 1b comprise longitudinal recesses 20, for example in the form of an elongated hole, which are arranged in sections in the longitudinal direction and in the region of a respective support or bearing element 19 of the test rail, whereby an optimized contact and / or alignment between the test rail 2 and the support rails 1a, 1b is achieved.Particularly advantageously, the longitudinal recesses 20 each have a greater extension in the longitudinal direction of the test element 10, in particular such that the respective longitudinal recess projects beyond the respective support or bearing element 19 on both sides in side view.

[0074] As shown in Fig. 7c, the connecting means of the test element 10 comprise recesses or mounting holes 21 at the two opposite ends. These are designed for fastening the connecting elements 17, 17a, 17b and extend perpendicular to the longitudinal direction through all components of the test element 10. The recesses 22a in the support elements 1a, 1b are larger in side view than the corresponding recesses 22b of the test rail(s) 2. As a result, a respective surface 7a, 7b of the intermediate test rail(s) 2 in side view and in particular a respective end-side contacting projection 13 of the test rail(s) 2 is arranged exposed, so that an electrical conductor 23 for contacting a respective test rail 2 can be brought up to it or contacted with it, as shown in Fig. 8a, b.

[0075] The connecting elements 17 for the test element 10 preferably comprise guide and / or clamping elements 24, for example in the form of a clampable conductor channel in which an electrical conductor 23 can be held on the test element 10 and in contact with a respective surface 7a, 7b of the test rail 2.

[0076] As further shown in Fig. 8a, b, the respective connecting element 17 is designed to receive a tightenable fastening bolt or pin 25, which extends vertically through the respective recess 21 and by means of which a respective conductor element 23 can be clamped in the conductor channel 24. The fastening pin 25 is screwed to a receiving bore 31a of the support element and, in the mounted state, penetrates the mounting holes 21 of the test element 10. The fastening pin 25 advantageously serves to at least partially compress or clamp the electrical conductor elements 23 in the conductor channels 24 of the connecting element 17, wherein the conductor elements 23 bear in electrical contact on the opposite side surfaces 7a, 7b of the test rail 2 arranged between the support rails 1a,b.

[0077] Fig. 8c shows a perspective side view of a preferred embodiment of a support element 31. This preferably comprises an at least partially projecting bearing section with the receiving bore 31a arranged therein and a rear connecting section 31b for connection to a support frame 30 of a testing device.

[0078] As can be seen from Fig. 9, the connecting element 17 also serves to arrange the test element 10 on a support or holding frame 30 of the test device or a test system, in particular in conjunction with a respective associated support element 31. The support frame 30 is designed for the preferably parallel arrangement of several test elements 10.

[0079] The connecting elements 17 are held by respectively assigned support elements 31 with a respective associated fastening pin 25. The support elements 31 are preferably arranged in corresponding recesses or receiving openings 32 of the support frame 30. The support elements 31 can be firmly screwed or fixed in the support frame 30 by means of rear-side connecting elements (not shown), for example a screw or pin connection, or can be mounted at least partially movably in the receiving opening 32. In this case, the test elements 10 are held in the support frame 30 preferably without any tensile stress acting on them in the longitudinal direction of the test elements 10.

[0080] List of reference symbols

[0081] 1a,b support rails

[0082] 2 test rail

[0083] 2a Basic body

[0084] 2b Spring elements

[0085] 2c Contact elements

[0086] 2d top edge of test rail

[0087] 3a, b interior surfaces

[0088] 4a, b contact surfaces

[0089] 5 Connecting and / or insulating materials

[0090] 6 inner recess

[0091] 6a inner contour

[0092] 7a, b Side surfaces of test rail

[0093] 8 Support element

[0094] 8a Contact stop

[0095] 9 Slide element

[0096] 9a Adhesive surfaces

[0097] 10 test elements

[0098] 11 Adhesive reservoir

[0099] 11 a Openings

[0100] 11 b Recesses test rail

[0101] 12 through openings

[0102] 13 contact projections test rail

[0103] 14 Contacting section contact elements

[0104] 15 finger electrodes

[0105] 16 solar cells

[0106] 17 Connecting element

[0107] 17a,b Connecting elements

[0108] 18 Guide element

[0109] 19 Support or bearing element 20 Longitudinal recesses support rail

[0110] 21 mounting holes test element

[0111] 22a Recesses support elements

[0112] 22b Recess test rail 23 Conductor element

[0113] 24 conductor channel

[0114] 25 fixing pin

[0115] 30 support frame test device

[0116] 31 Support element 31a Mounting hole

[0117] 31 b connecting section

[0118] 32 Support element receiving opening

[0119] L Longitudinal direction of test rail

[0120] L1 Length contact section

Claims

Patent claims 1. Test element (10) for the detachable electrical contacting of an electrically conductive substrate, in particular a busbarless solar cell, comprising two preferably lamellar support rails (1a, 1b) with at least one lamellar test rail (2) arranged therebetween, comprising a base body (2a) and a plurality of contact elements (2c) arranged on one side thereon and formed integrally with the base body, characterized in that at least one of opposite inner surfaces (3a, 3b) of the support rails (1a, 1b) has a surface structured for interaction with the test rail (2), and in that the inner surfaces (3a, 3b) form contact surfaces (4a, 4b) which are aligned with one another and are connected to one another, preferably by means of a material bond, by means of connecting and / or insulating means (5) arranged therebetween.

2. Test element according to claim 1, characterized in that the structured surface forms an inner recess (6) which is designed to at least partially receive and securely support the test rail (2).

3. Test element according to claim 1 or 2, characterized in that the structured surface forms an inner contour (6a) which is adapted to an outer contour of the test rail (2), in particular in a side view of the test element.

4. Test element according to claim 2 or 3, characterized in that the inner recess (6) has a depth (t) which is designed such that the test rail (2) is in contact with a surface extending from the recess (6) facing away from the side surface (7b) is arranged flush with an inner surface (3a, 3b) surrounding the inner recess (6).

5. Test element according to one of the preceding claims, characterized in that the structured surface forms and / or comprises a support element (8) which forms at least one contact stop (8a), preferably extending in the longitudinal direction (L) of the test element (10), for an upper edge (2d) of the test rail (2) arranged opposite the contact elements (2c) of the test rail (2).

6. Test element according to claim 5, characterized in that the support element (8) is formed in a lower edge of an inner recess (6) of a support rail (1a, 1b) aligned with the test rail (2).

7. Test element according to one of the preceding claims, characterized in that an upper edge of the test rail (2) has at least one or more support or bearing elements (19) arranged therein, in particular in sections, which are designed to bear against the structured surface and / or a support element (8) of the structured surface of the support rails.

8. Test element according to claim 7, characterized in that one of the support rails (1 a, 1 b), preferably both support rails, have one or more elongated recesses (20), which are preferably arranged in sections in the longitudinal direction (L) and in the region of a respective support or bearing element (19) of the test rail (2).

9. Test element according to one of the preceding claims, characterized in that the connecting and / or insulating means (5) comprise a preferably insulating film element (9) arranged between the support rails (1 a, 1 b) with adhesive surfaces (9a) arranged on both sides.

10. Test element according to claim 9, characterized in that the opposite contact surfaces (4a, 4b) lie directly on both sides of the film element (9), in particular without intermediate layers.

11. Test element according to claim 9 or 10, characterized in that the film element (9) has an outer contour substantially corresponding to the support rails (1 a, 1 b).

12. Test element according to one of the preceding claims, characterized in that the connecting and / or insulating means (5) comprise at least one, preferably a plurality of adhesive reservoirs (11) formed in the support rails (1a, 1b) and / or in the test rail (2) and preferably open to the outside.

13. Test element according to claim 12, characterized in that the adhesive reservoirs (11) are formed at least partially by the structured surfaces of the opposing inner surfaces (3a, 3b) of the support rails (1a, 1b).

14. Test element according to claim 12 or 13, characterized in that the adhesive reservoirs (11) are formed at least partially by recesses in an upper edge of the test rail (2).

15. Test element according to one of claims 12 to 14, characterized in that the adhesive reservoirs (11) in the longitudinal direction (L) of the test element (10) are arranged distributed and / or have an opening (11a) directed outwards and in particular in the direction of an upper edge of the test element (10) for filling the reservoirs (11).

16. Test element according to one of the preceding claims, characterized in that the connecting and / or insulating means (5) comprise at least one, preferably a plurality of through openings (12) formed in the test rails (2) and filled with adhesive.

17. Test element according to one of the preceding claims, characterized in that the through-openings (12) filled with adhesive have a flat design such that a longitudinal extent or a radius of the respective through-opening is greater than a depth of the respective through-opening perpendicular to the longitudinal extent.

18. Test element according to one of the preceding claims, characterized in that the two support rails (1 a, 1 b) have a substantially identical outer contour, 19. Test element according to one of the preceding claims, characterized in that the mutually aligned contact surfaces (4a, 4b) each have a flat surface.

20. Test element according to one of the preceding claims, characterized in that the support rail (1) has flat outer surfaces. 21 . Test element according to one of the preceding claims, characterized in that the test element has at least one second and / or third test rail (2',2"), which are arranged electrically separated from the first test rail (2) by an insulating rail.

22. Test element according to one of the preceding claims, characterized in that the test element (10) has two connecting elements (17, 17a, 17b) which are opposite one another in the longitudinal direction and which serve to arrange the test element on a support or holding frame (30) of a test device or a test system.

23. Test element according to claim 22, characterized in that the connecting elements (17, 17a, 17b) have at least one, preferably two guide and / or clamping elements (24), preferably in the form of a respective clampable conductor channel in which an electrical conductor (23) can be held on the test element (10) and in contact with a respective surface (7a, 7b) of the test rail (2).

24. Use of the test element (10) according to one of the preceding claims for testing a preferably busbarless solar cell (S), in particular for measuring current intensity and / or current voltage, by means of electrical contacting of finger electrodes arranged parallel on the solar cell surface and preferably with simultaneous exposure of the solar cell to light.

Images