WO2014111447A1 - Reference solar cell arrangement - Google Patents

Abstract

The invention comprises a reference solar cell arrangement which has a solar cell having a first solar cell main surface and a second solar cell main surface and a housing (41) in which the solar cell is enclosed. The housing (41) has a connection panel (2) which can be used to set up an electrical connection which leaves the housing (41) in a manner exiting the solar cell. Electrical contact is not made with the entire area of the solar cell on that of the two main surfaces which is not intended to be irradiated with incident light.

Description

 Patent Application:

 Reference solar cell array

applicant:

 Fraunhofer-Gesellschaft for the promotion of applied research e.V.

The application relates to the construction of a reference solar cell array and a reference solar module, which consists of several reference solar cells. When

Reference solar cell array is referred to here a reference solar cell, which is fitted in a housing. Reference solar cell arrays are preferably used for calibrating solar cells, solar modules, solar systems or solar simulators. This calibration can take place both "indoor", ie in measuring laboratories and production facilities, as well as "outdoor", that is, e.g. Locally installed solar modules, potentially interesting installation locations or similar. Furthermore, reference solar cell arrays are generally suitable for precise measurements in the field of metrology and meteorology. As an example, high-precision light intensity and light irradiation measurements can be mentioned, which can be carried out using reference solar cell arrays.

The need for reliable and precise reference solar cell arrays is great and is among others manufacturers, users and

 Research facilities in the field of photovoltaics, metrology and

Meteorology.

So far, however, there are mainly reference solar cell arrays that contain small area solar cells. The size of the solar cells used is usually less than 5 cm x 5 cm and is typically in the range 2 cm x 2 cm. The design of a typical reference solar cell array is described in a publication of the World Photovoltaic Scale [CR. Osterwald et al., The World Photovoltaic Scale: An International Reference Cell Calibration Program, Conference Record of the 26th IEEE Photovoltaic Specialists Conference, Anaheim, USA, 1997]. The World Photovoltaic Scale is considered an international standard for calibrating reference solar cells for primary and secondary calibration. The cited publication describes the use of a 20 mm x 20 mm monocrystalline float-zone silicon solar cell as a reference solar cell, which is located on a plate made of a copper-nickel alloy. The commercially available reference solar cell assemblies also typically include small area solar cells. As an example, the indoor and outdoor reference solar cell arrangements offered by the Photovoltaic Calibration Laboratory of the Fraunhofer ISE (CalLab), which contain an active solar cell area of 20 mm x 20 mm with a tolerance of less than 10 μm, may be mentioned here. However, the use of a reference solar cell array with a small area solar cell has significant disadvantages.

On the one hand, inhomogeneities of the radiation intensity or the

Radiation spectrum of the solar simulator used in an indoor measurement when using a small-area reference solar cell can be evaluated and corrected only with great effort.

Since the production of solar simulators with a good homogeneity of the

Radiation intensity on the irradiated level is technically very complex, commercially available and often used in practice solar simulators for economic reasons often have a poor homogeneity of the radiation intensity in the irradiated measuring range. For measuring the incident light intensity, small-area reference solar cells are often used in which the area of the solar cell is small compared to the irradiated measuring area. Consequently, the reference solar cells can determine the light intensity only in a small area of the entire irradiated measuring range. The remaining areas of the measuring range are evaluated inadequately, depending on the quality of the homogeneity of the solar simulator. Although a recording of the homogeneity profile of the irradiated measuring range by means of a plurality of individual measurements using a small-area solar cell and subsequent determination of a correction factor is theoretically conceivable, it is very complicated and, moreover, in principle error-prone. Even when using a solar simulator with high quality with respect to the homogeneity of the irradiated

Light intensity should always be compared to solar cell samples with reference solar cells of the same aperture to reduce calibration errors.

Another disadvantage of small-area reference solar cells is the large spectral mismatch, which is in principle associated with the different solar cell design of the solar cell used in the reference solar cell array and the solar cell to be examined. In particular, the solar cells used in reference solar cell arrays are often lab-made high efficiency solar cells that have excellent absorption over a broad wavelength range and moreover, with only very low contact resistances in the field

Reference solar cell array are interconnected. At the to be measured

 Solar cell samples, on the other hand, are usually industrially produced standard solar cells whose spectral absorption is less pronounced and which potentially have various other, possibly significant, current, voltage and fill factor losses. There are various methods for considering the spectral mismatch between the solar cell used in the reference solar cell array and the

examined solar cell. Ideally, however, one would minimize the spectral mismatch from the outset by selecting a solar cell for the reference solar cell array whose solar cell design matches that of the one to be investigated

Solar cell samples comes as close as possible.

An object of the invention is to provide an improved

Reference solar cell array, including the installation of large-scale

Solar cells enabled.

The invention comprises a reference solar cell arrangement, which consists of at least one solar cell and a housing in which the solar cell is enclosed. The case has a connector panel that allows you to get out of the way Solar cell, can set up an electrical connection leaving the housing. This electrical connection can be permanently established or separable. The solar cell is not fully electrically contacted on that of the two main surfaces, which is not intended for irradiation with incident light. Solar cells are generally flat, that is, they have two substantially mutually parallel main surfaces, as well as other narrow sides, the area each clearly, ie in particular by at least one

Decimal power is less than that of both major surfaces. It goes without saying that each real solar cell can have process-related unevenness as well as structuring on its main surfaces.

A reference solar cell array always consists of a housing, which was usually developed specifically for the particular arrangement. Due to the encapsulation of the solar cell in the housing, the permanent preservation of the

Solar cell properties guaranteed. In particular, the solar cell is protected from environmental influences such as temperature, humidity and mechanical stress.

The connection field, which is part of the housing, ensures permanent and precisely reproducible contacting of the solar cell.

Furthermore, reference solar cell arrays are typically incorporated in operation such that the one major surface of the solar cell faces the incident light, while the other major surface faces the laminate and the solar cell

Rear wall facing. Hereinafter, the main surface facing the incident light becomes the front of the solar cell and the other

Main surface referred to as the back of the solar cell. In conventional reference solar cell arrangements, the electrical contact between the solar cell rear side and the current-carrying means is always formed over the entire surface. For example, in a typical

Reference solar cell array, the solar cell directly to a plate of an electrically and thermally highly conductive material, such as a nickel-copper alloy, positioned and fixed. Fixing here means that the solar cell and other components of the reference solar cell array, such as a

Temperature sensor, the wiring or the support plate, encapsulated in the housing to ensure a long-lasting stable and accurate operation.

The advantages of the direct connection between the solar cell rear side and the support plate consist in a homogeneous thermal coupling of the solar cell to a heat-conducting medium. On the other hand, a relatively low electrical resistance between the rear contact of the solar cell and the support plate can thus be realized.

It should be noted that the thermal expansion coefficients of the two superimposed or pressed materials, namely

 Solar cell and the platen, usually have significant differences. Since it is principally under irradiation to a warming of

Reference solar cell array comes is an extension of some of their

Components, such as the solar cell and the support plate, unavoidable.

Typically, the solar cell consists of a semiconductor material such as silicon or a compound semiconductor with elements of III. and V. main group and the support plate made of an alloy of different metals. In this case, the coefficients of expansion differ considerably.

In the case of small-area reference solar cell arrangements in which the size of the solar cell does not exceed a value in the range of 20 mm × 20 mm, the negative effects resulting from the different coefficients of expansion are generally not significant. However, since the highest demands are placed on precision and long-term stability especially on reference solar cells, a solution of the problems associated with the different expansion is in principle also desirable in the case of small-area reference solar cell arrangements.

In large-scale reference solar cell array, which contains a solar cell with an electrically active area of, for example, greater than 50 mm x 50 mm, for example, to the above-described disadvantages of the inhomogeneities of

Radiation intensity or the radiation spectrum or the spectral mismatch to counter, the effect of the different

Expansion coefficients become very significant. When heating the It can then lead to strains and warping in the solar cell, even cracks and fractures have already been observed empirically. For this reason, large-scale reference solar cell arrays have not prevailed so far. According to the invention, it has been recognized that a novel rear-side contacting of the solar cell in the reference solar cell arrangement is required.

One solution to the problem is to avoid full-surface contact between the back of the solar cell and the platen. Instead of contacting the rear side of the solar cell with the electrically conductive support plate over the entire area, alternative contacting structures are used in which the main surface of the solar cell, which is not intended for irradiation with incident light, does not make electrical contact over the entire area.

These contacting structures may, for example, be current collectors which consist of an electrically conductive material and are applied to the rear side of the solar cell. If the back is covered with an insulating layer, it may need to be removed locally. If the front side of the solar cell for discharging the charge carriers has current collectors, it may be advantageous for the current collectors on the rear side to have a similar geometry and arrangement to the current collectors on the front side. This will be a

Asymmetric thermo-mechanical stress on the current collector avoided and thus minimizes a parasitic sheet resistance.

One possible embodiment of the current collectors are current busbars, so-called busbars. These are usually orthogonal to the contact fingers, which are typically applied to the solar cell front side. Another embodiment of the current collectors are so-called contact pads or a directly applied finger metallization. These can be contact points in any size and geometry. Again, it may be advantageous to adjust the contact on the back of the contact structure on the front.

If the above-described contacting structures are used instead of full-surface back contact, other types of solar cell can now also be used the reference solar cell array can be used. An example of this is

Backside contact cells where both the emitter and base contacts are on the back side. With a suitable contacting and interconnection, these can be installed in the housing and both contacts are led from the solar cell to the outside. Other examples of alternative, backside-structured solar cells are emitter-wrap-through (EWT) and metal-wrap-through (MWT) solar cells.

Apart from the previously mentioned solar cells whose electrically active layer consists of a crystalline semiconductor material, other solar cell types, such as thin-film solar cells, organic solar cells or dye solar cells can be used in the reference solar cell array according to the invention.

Since the contacting of the back of the solar cell by other means and

Measures, as previously known in the prior art for reference solar cells, is reached, is an essential consequence that the support plate has become obsolete in the reference solar cell array. As a result, the problem of different thermal expansion coefficients no longer arises. A consequence of this is, in particular, that reference solar cell arrangements with large-area solar cells are now possible.

It may be surprising in retrospect that so far no

Reference solar cell arrays have been developed in which the

 Solar cell main surface, which is not intended for irradiation with incident light, not fully contacted electrically. Such solar cells are finally known from the prior art. The with the development of

Reference solar cells busy professionals has apparently not adequately analyzed the problem and therefore always chose as a solution not to use large-scale solar cells. This was basically useful

Reference solar cell arrangements available, which, however, had the disadvantages described above. Only the invention

Reference solar cell array allows the use of large-area solar cells and allows the associated benefits. According to one embodiment of the inventive arrangement, the reference solar cell array includes a temperature sensor, which is in thermal contact with the solar cell and allows detection of the solar cell temperature.

For high-precision and reliable measurements with a reference solar cell array, it is important to know the exact temperature of the reference solar cell during the measurement because the measured current and voltage are usually dependent on the cell temperature. Are the temperature coefficients of

Reference solar cell, ie the correlation of current and voltage with the cell temperature, as well as the temperature of the solar cell to be compared, the measured values of the reference solar cell can be corrected.

In conventional reference solar cell arrays, the temperature sensor is typically spring-biased to the underside of the platen while the reference solar cell is in good thermal contact with the top of the platen. In the reference solar cell arrangement according to the invention, however, the temperature sensor is preferably directly to the back of the

 Reference solar cell attached. The temperature of the solar cell during the measurement can thus be determined directly and directly. The temperature sensor may for example be a Pt100 sensor based on the dependence of the electrical resistance on the temperature of platinum. For example, the Pt100 sensor may be attached to the solar cell with a thermally conductive adhesive or thermally conductive paste.

According to a further embodiment of the invention

Reference solar cell array, this is suitable to integrate a wide range of solar cells in the arrangement. This can also be commercially available

Standard solar cells are used. As the size of the solar cell in

conventional reference solar cell arrays is usually limited to dimensions in the range 20 mm x 20 mm, there are used as solar cells typically in the laboratory specially made high-efficiency solar cells, since solar cells with these dimensions are difficult to produce in industrial production. On the other hand, it is desirable that the reference solar cell and the solar cell to be compared are as similar as possible, for example for reducing the spectral mismatches. In the arrangement according to the invention solar cells of any size can be installed in principle, if the housing is adjusted accordingly. Thus, for example, it is possible for a manufacturer of solar cells, who would like to check the characteristics of the finished solar cells of a process line, to make a reference solar cell arrangement in which a representative solar cell from the process line whose solar cells he would like to check, into the arrangement with relatively little effort is integrated.

The reference solar cell arrangement can thus be optimized for the test objects to be examined. This refers to the solar cells just mentioned. On the other hand, however, this can also be applied to the other components of the

 Expand arrangement, for example, on the front, encapsulation and backing materials used. Again, it is desirable if these components are as similar as possible in the reference solar cell array and the solar cell or the solar module to be measured. Again, it is possible that

Reference solar cell array to suit the needs of the user.

According to a further embodiment of the invention

Reference solar cell array, the frame of the housing is designed such that the angular acceptance of the arrangement is at least 160 °, preferably at least 170 °.

Angular acceptance describes the maximum angle at which incident rays can strike the reference solar cell array without at least partially shading the solar cell. The shading can be done for example by parts of the housing frame. The angular acceptance plays a role especially in outdoor measurements, in which it is not uncommon that the

 Solar radiation incident at least in part at a large angle away from the normal of the solar cell to this. A high angular acceptance can be achieved for example by a housing profile whose edge is flattened towards the solar cell. According to a further embodiment of the invention

Reference solar cell assembly, the housing is designed such that the Total height of the reference solar cell array is at most 30 mm, preferably at most 20 mm, particularly preferably at most 10 mm.

A flat trained reference solar cell array is usually advantageous because it is more versatile. If, for example, measurements taken with the aid of a solar simulator, ie so-called indoor measurements, are determined in a first step, the solar cell characteristics of the reference solar cell array removes them from the location of the measurement, places the solar cell to be examined at this location and determines in a second Step under the same measuring conditions the parameters to be examined solar cell. Among other things, care must be taken with these comparative measurements that the distance from the solar cell to be examined and from the reference solar cell to the irradiation source, the solar simulator, is the same in both cases. A flat housing of the reference solar cell array can be quite advantageous here. According to a further embodiment of the invention

 Reference solar cell array is ensured by means of a thermally highly conductive and compressible material, the homogeneous thermal coupling of the solar cell to the housing and the environment.

This good thermal coupling of the solar cell to the laminate and the housing and the environment can be realized for example by a so-called adaptation mat and / or the use of potting material. Furthermore, it should be noted that in one possible embodiment of the arrangement according to the invention, the housing substantially consists of only one frame. The housing is thus open in the direction of the incident radiation and on the opposite side. This ensures optimum thermal coupling of the solar cell to the environment.

According to a further embodiment of the invention

Reference solar cell array are due to the special design of the

Housing parasitic horizontal light pipe effects in the cover glass minimized.

This means, above all, that the housing frame essentially prevents coupling of the incident radiation over the glass sides. Consequently The measured power of the reference solar cell essentially results from the radiation incident directly on the reference solar cell and is not caused by additional radiation that passes over edges of the cover glass into the solar cell

be coupled, falsified. According to a further embodiment of the invention

 Reference solar cell array are base, emitter and terminal box as well

Connections of base and emitter to the connection field potential-free to the housing. This ensures the electrical insulation of the base and the emitter with respect to the housing. In the reference solar cell array according to the invention, it is necessary to provide an electrical connection between the base of the reference solar cell and the

Terminal field and between the emitter of the reference solar cell and the

To realize connection field. The entirety of the electrical connectors will hereinafter be referred to as internal circuitry. In order to ensure the electrical insulation of the base and emitter with respect to the housing, so that, for example, the

Housing that in direct contact with a human operator

Reference solar cell array can stand, carries no voltage, base, emitter and connection pad and connections of base and emitter to

Connection panel potential-free to the housing. Electrical insulation of the base and emitter with respect to the housing is also important so that there is no electrical connection from the housing to other devices in the vicinity of the housing

Reference solar cell array may arise. The isolation of the interconnection can e.g. by inserting insulating material between the different ones

electrical connector done. According to a further embodiment of the invention

 Reference solar cell arrangement allows the terminal pad contacting and receiving a shunt resistor, which is also referred to as a shunt resistor.

The connection field itself fulfills several tasks. It serves to interconnect the electrical connectors and the connector. It enables a permanent and precisely reproducible contact. The shape of the connection field is used In addition, as a handling aid, carries the mounting holes and represents the mechanical focus of the housing.

In the arrangement according to the invention, the connection field furthermore serves to receive a shunt resistor. A shunt resistor is understood to be a low-resistance electrical resistor which is used to measure the electric current. This shunt resistor can be mounted in the terminal box, for example, soldered. It is important that the corresponding electrical

Connections designed as short as possible and are connected symmetrically, which is possible by mounting the shunt resistor in the connection field. Furthermore, the shunt resistance can be cooled by simple means when mounted on the housing.

According to a further embodiment of the invention

Reference solar cell array are the base and emitter contacts of

Reference solar cell connected to Kontaktierungsschienen that dissipate the current at the same edge of the solar cell.

As explained above, electrical connectors serve to conduct the current from the contacts on the solar cell to the terminal pad. The electrical connectors can be made as Kontaktierungsschienen. They consist of a material with good electrical conductivity and are in a preferred

 Embodiment rigid. Thus, the Kontaktierungsschienen can be controlled in the housing position.

For high-precision measurements, it is important to know exactly the contact resistance of the base and emitter contacts so that they can be correctly taken into account when evaluating the measurement results. For example, the reference solar cell has current bus bars, called busbars, on its front side as well

Current busbars in similar geometry and arrangement on their back, the inner interconnection may be configured so that it contains Kontaktierungsschienen that connect the front side busbars to the terminal box and the back current busbars to the connection pad. In a preferred embodiment, these Kontaktierungsschienen perform the current at the same edge and are similar in geometry. With such a structure, the differences in the contact resistance of the base and the emitter contact are significantly reduced and facilitates an evaluation of the measurement results.

In a further embodiment of the invention

Reference solar cell arrangement, the contact rails are electrically isolated from each other.

In particular, if the contact rails of the emitter and base are removed at the same edge of the reference solar cell and are similar in geometry and arrangement, the contacting rails could at least partially and temporarily touch without suitable countermeasures. This would lead to a short circuit and it goes without saying to avoid.

According to a further embodiment of the invention

Reference solar cell array is the electrical isolation of

 Contact rails of base and emitter realized by a multi-layer system of insulating materials.

These materials may be, for example, nonwoven and ethylene vinyl acetate. The combination of both materials can ensure the reliable electrical insulation of the contacting rails. A thin layer of fleece between the

Kontaktierungsschienen thereby ensures the insulation, while the

Ethylene vinyl acetate takes over the role of the encapsulating material.

If a temperature sensor is integrated in the arrangement, this too can be insulated by an adapted and correspondingly positioned layer of insulating material,

For example, nonwoven, be electrically isolated from the other components of the arrangement.

According to a further embodiment of the invention

Reference solar cell array, the electrical isolation of the Kontaktierungsschienen by embedding the same in an insulating

Encapsulating material, for example ethylene vinyl acetate, take place.

For this purpose, the encapsulating material at temperatures above the

melted material typical melting. After cooling, there is a permanent bond, which is particularly heat-resistant and good

Has aging properties. This variant of the insulation of the inner circuit saves the use of separate thin insulating layers, such as nonwoven fabric.

Another variant is the use of multilayer flexible conductor foils or printed circuit boards, which also ensures a reliable and stable electrical insulation of the inner circuit and manages without a complex multi-layer system.

If the reference solar cell array contains a temperature sensor, electrical connections to the connection field usually have to be made for this as well. It is important to ensure that in this case, the electrical connections of the temperature sensor with respect to the Kontaktierungsschienen are electrically isolated from each other.

Furthermore, the invention comprises a reference solar cell array containing a plurality of solar cells. Such a reference solar cell arrangement is also referred to below as a reference solar module.

A reference solar module is used in particular for calibrating measurements of

Solar modules needed. Analogous to small-area reference solar cells, which are successively positioned at different locations in the measuring range and each perform separate measurements in order to obtain a reference point of a reference measurement over the entire measuring range, it is also possible with a simple reference solar cell by successive measurements, the entire surface of a Cover to be examined solar module. However, this type of reference measurement at the module level is just as flawed as the reference measurement on large-area solar cells using a small-area reference solar cell. One Reference solar module with a similar aperture as the solar modules to be examined is therefore desirable.

This problem is solved by the use of a reference solar module according to the invention, that is to say a reference solar cell arrangement which has several

Solar cells includes. It ideally contains solar cells that have similar geometric and spectral properties as the solar cells in the solar module to be examined. In addition to the solar cells, the reference solar module also consists of a housing, an encapsulation and a connection field. The interconnection of the individual solar cells with each other makes sense to choose. If all solar cells are contacted individually, all existing solar cells are potentially electrically active. On the other hand, it is also possible to contact and interconnect only individual solar cells, so that only these are electrically active and contribute to the reference measurement. Analogous to the reference solar cell arrangement is also in the construction of the reference solar module mainly on the permanent preservation of

To pay attention to solar module properties and precise and reproducible solar module characteristics.

The invention will be explained in more detail with reference to several figures. Furthermore, an embodiment of the invention will be described. Show it

Figure 1: Housing a reference solar cell array Figure 2: Structure of a reference solar cell

FIG. 3: cross-section of a reference solar cell

Figure 4: Clarification of an improved angular acceptance of

 Reference solar cell array

Figure 5: Structure of a reference solar module Figure 1 shows schematically a part of the housing 1 a

Reference solar cell array. It consists for example of aluminum, which has been anodized and blackened. It has a connection field 2, which is the interconnection of the serves electrical connector and carries openings for the connector 4. Two openings are provided for the base and emitter contact of the reference solar cell, the third opening for the resistance thermometer, ie the temperature sensor.

If, for example, you want to connect a shunt resistor, this is possible internally in the connection field.

The connection panel 2 allows a durable and precisely reproducible

Contacting. The shape of the connection field 2 also serves as

Handling aid, carries the mounting holes 3 and represents the mechanical center of gravity of the housing. Figure 2 shows the structure of a reference solar cell 42 as an exploded view. The structure is shown with the front side down. A backsheet 21 closes the composite down. This can for example consist of a

There are three-layer TPT structure, namely a high-performance polyethylene terephthalate film for electrical insulation between two Tedlar® films. Two layers of encapsulating material 22, consisting e.g. Ethylene vinyl acetate, provide a homogeneous thermal coupling and protect the cell structure from pressure during the lamination process. The contacts of a precise four-wire type temperature sensor 24, e.g. a Pt100 sensor according to DI N EN 60751: 2009-05 are electrically separated from the backside of the active region 25 of the solar cell 42 by a non-woven fabric 23. The electrical insulation is realized only for the contacts of the temperature sensor 24; The Pt100 sensor has direct thermal and electrical contact with the solar cell back. The active region 25 of the solar cell 42 may be embodied in various forms technologically, for example, it may be a crystalline silicon solar cell (monocrystalline, multicrystalline, quasi-monocrystalline), consisting of compound semiconductors (eg I l IV semiconductors or l l-VI). Semiconductor), consist of organic semiconductors, a dye solar cell or thin film solar cell. An example of a silicon solar cell is a commercially available multicrystalline solar cell in the size 156 mm x 156 mm.

A composite of encapsulation material 26 and nonwoven 27 electrically isolates base contacts 28 and emitter contacts 28 'of the active region 25 of the solar cell 42 from each other. The emitter contact 28 'and the base contact 28 are each in Four-wire technology designed to minimize ohmic resistance effects. Another composite of encapsulation material 29 and backsheet 30 serves as a cover to the front to avoid reflections. As the front cover is an outer encapsulation material 31 and a glass pane 32. Als

Glass pane can e.g. Low-iron float glass in the form of single-pane safety glass can be used. This improves the transmission and increases safety in the event of a glass breakage.

FIG. 3 shows the cross section of the encapsulated reference solar cell. The

Numbered elements are explained in more detail in the description of FIG. FIG. 3 illustrates that the problem of the electrical insulation of the individual

Components base contact 28, emitter contact 28 'and temperature sensor 24 by an innovative multi-layer system of encapsulation material 31, fleece 27 and backsheet 30 has been solved.

FIG. 4 clarifies the concept of angular acceptance

Reference solar cell arrangements and how the angular acceptance was optimized in the present invention. The housing frame 41 represents the lateral boundary of the reference solar cell array and consists for example of black anodized aluminum. On the front side of the arrangement, the frame is flattened toward the reference solar cell 42, which is shown in greater detail in FIGS. 2 and 3, at an angle which is, for example, in the range of 5 ° to 15 °. The reference solar cell 42 is embedded in a further encapsulation material 43. To the front of the structure with a glass plate 44, such as single-pane safety glass, protected.

Now rays 45, starting from a radiation source 46, hit the

Reference solar cell array, it depends on the design of the

Box frame and from the positioning of the reference solar cell 42 relative to the completion of the housing frame 41 from whether and optionally in which

Irradiation angle the reference solar cell 42 partially or completely from

Case 41 is shaded. FIG. 4 shows the irradiation angle of the radiation source 46, which is maximally large in relation to the normal of the reference solar cell 42 in order not yet to cause any shading of the reference solar cell 42. As the angle of incidence increases, the radiation source 46 becomes Partially shaded facing lateral areas of the reference solar cell 42. In practice, a compromise often has to be chosen between one

maximum angular acceptance on the one hand and a housing frame height, which still gives a sufficiently good mechanical stability, a technologically meaningful thickness of the cover and a reasonable distance of the

 Reference solar cell 42 to complete the housing frame 41 on the other side.

FIG. 5 describes the structure of a reference solar module 51 with nine

Solar cells which correspond to the reference solar cells 42 described above and are numbered 52 and 53a to 53h to distinguish here from each other. For example, only the solar cell 52 is contacted and thus electrically active, while the remaining solar cells 53a to 53h are not contacted and thus electrically inactive. On the other hand, it is also possible that several solar cells are contacted and electrically active. If a reference measurement is now carried out on a solar module to be examined with this reference solar module 51, the use of the described reference solar cell module 51 having a plurality of solar cells has advantages over the reference measurement on a solar module to be examined with a solar module

Reference solar cell array comprising only one solar cell. Thus, in a reference measurement with a reference solar module, influences of the neighboring solar cells can be taken into account, e.g. Reflections or heat conduction effects. If, furthermore, an arrangement is selected in which several solar cells are contacted and electrically active, so that the aperture of the solar module to be examined and the reference module adjoin, this has further advantages, in particular with inhomogeneous radiation sources.

Claims

claims A reference solar cell array comprising a solar cell (42) having a first main solar cell surface and a second main solar cell surface, and a housing (41) incorporating the solar cell (42), the housing (41) having a terminal pad (2) which, starting from the Solar cell (42), one leaves the housing (41) leaving electrical connection,  characterized in that  the solar cell main surface, which is not intended for irradiation with incident light, is not electrically contacted over the entire surface. 2. Reference solar cell arrangement according to claim 1,  characterized in that  the reference solar cell array includes a temperature sensor (24) in thermal contact with the solar cell (42). 3. Reference solar cell arrangement according to one of the preceding claims, characterized in that  the solar cell (42) is selectable from a wide range of solar cells and / or the use of various front, encapsulant and backing materials (29, 30, 31) is possible. 4. Reference solar cell arrangement according to one of the preceding claims, characterized in that  the frame of the housing (41) is designed such that the angular acceptance of the reference solar cell array is at least 160 °, preferably at least 170 °. 5. Reference solar cell arrangement according to one of the preceding claims, characterized in that  the housing (41) is designed such that the overall height of the Reference solar cell array at most 30 mm, preferably at most 20 mm, more preferably at most 10 mm. 6. Reference solar cell arrangement according to one of the preceding claims, characterized in that  a homogeneous thermal coupling of the solar cell to the housing (41) and the environment is ensured via the solar cell main surface, which is not intended for irradiation with incident light. 7. Reference solar cell arrangement according to one of the preceding claims, characterized in that  the housing (41) is formed so that parasitic horizontal  Lichtleitungseffekte in a transparent cover (32) of the housing (41) are minimized. 8. Reference solar cell arrangement according to one of the preceding claims, characterized in that  Base (28 '), emitter (28') and connection pad (2) and connections of the base and emitter to the connection field (2) potential-free to the housing (41) are executed. 9. Reference solar cell arrangement according to one of the preceding claims, characterized in that  the connection field (2) a contacting and recording of  Shunt resistance allows. 10. Reference solar cell arrangement according to one of the preceding claims, characterized in that  Base and emitter contacts (28 ') of the solar cell are connected to Kontaktierungsschienen and the Kontaktierungsschienen are adapted to supply the current to the same edge of the solar cell and / or dissipate. 1 1. Reference solar cell arrangement according to claim 10,  characterized in that  the Kontaktierungsschienen are electrically insulated from each other. 12. Reference solar cell arrangement according to claim 1 1, characterized in that for electrically insulating the contact rails of the base (28 ') and emitter (28'), the contacting rails are embedded in an encapsulating material which contains or comprises an insulating spacer, preferably non-woven and ethylene-vinyl acetate. Reference solar cell arrangement according to one of claims 2 to 12, characterized in that the temperature sensor (24) with respect to the Kontaktierungsschienen of the base (28 ') and emitter (28') and with respect to the housing (41) is electrically insulated. Reference solar cell arrangement according to one of the preceding claims, characterized in that the reference solar cell array comprises at least two solar cells and forms a reference solar module (51).