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1. (WO2017102957) SOLAR MODULE
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Solar module

Field of the invention

The present invention relates to a solar module comprising a plurality of solar cells, a back contact sheet for connecting the plurality of solar cells in one or more strings (using isolation scribes) and a plurality of clusters of back side contacts, each cluster being associated with one of the plurality of solar cells for providing electrical contact to the back contact sheet.

Background art

International patent publication WO2015/150471 discloses various embodiments of solar modules comprising a plurality of solar cells arranged in a regular grid pattern, and a back contact sheet for providing various connecting string patterns in the solar module.

International patent publication WO2012/167291 discloses a photovoltaic module with a plurality of solar cells, wherein flexible connecting regions are provided between two adjacent cells, allowing bending/tilting/folding of the module at a flexible connecting region. In all embodiments shown in the figures, the cells themselves are arranged in a regular (i.e.

rectangular) grid pattern.

International patent publication WO2013/164536 discloses a PV module with a substrate and a plurality of juxtaposed cells. The cells are interconnected in a parallel and/or serial circuit to form a macro-cell. The module is disclosed as having a visual effect, which is defined by the contour and surface extension of the active surface area of the module. This is accomplished by some of the cells having different constituent material, e.g. with a different absorption spectrum.

The entire disclosure relates to printed (thin film) PV cells, especially using inkjet printing techniques. The inkjet process and constituents of the printed layers is then the cause of a different visual effect of the surface of the cells 6.

Summary of the invention

The present invention seeks to provide a solar cell with more flexibility in possible appearance, especially suitable for building integrated photovoltaic (BIPV), infrastructure integrated photovoltaic (I2PV) and landscape integrated photovoltaic (LIPV) applications.

According to the present invention, a solar module according to the preamble defined above is provided, wherein at least one of the plurality of solar cells is positioned outside of a regular grid pattern, and the back contact sheet and/or the plurality of clusters of back side contacts is adapted locally to contact the at least one of the plurality of solar cells with the associated string of the one or more strings. This allows to provide a technical solution to obtain (back contact) solar modules having much more flexibility in appearance than prior art solar modules.

Short description of drawings

The present invention will be discussed in more detail below, using a number of exemplary embodiments, with reference to the attached drawings, in which

Fig. 1 shows a schematic view of a part of a solar module according to an embodiment of the present invention;

Fig. 2 shows a schematic view of a back contact sheet associated with the solar module 1 embodiment as shown in Fig. 1 ;

Fig. 3 shows a composite view of the three layers of the solar module embodiment of Fig.

1 and 2;

Fig. 4 shows a composite view of the three layers of a further exemplary embodiment of a solar module;

Fig. 5a shows a schematic view of one solar cell in a regular grid pattern of a solar module, and

Fig. 5b shows a schematic view of an embodiment wherein the at least one of the plurality of solar cells is divided in two or more parts to extend the solar cell outside of the regular grid pattern;

Fig. 6 shows a composite view of the three layers of a further exemplary embodiment of a solar module using the solar cell of Fig. 5b; and

Fig. 7 shows a schematic view of a solar module according to an even further embodiment of the present invention.

Description of embodiments

The present invention relates to the ability to provide solar modules 1 having a high degree of design flexibility, especially with respect to the appearance of the solar module 1 . In the field of Build Integrated Photo-Voltaic (BIPV) applications the appearance of solar modules 1 is becoming more and more important, as well as in the field of infrastructure integrated photovoltaic (I2PV) and landscape integrated photovoltaic (LIPV).

In general, solar modules 1 are composed of three major parts, i.e. a plurality of solar cells 2, a back contact sheet 3, and a plurality of clusters 7 of contacts 4 between (back side) contact points of each solar cell 2 and associated parts of the back contact sheet 3 for forming one or more strings of interconnected solar cells 2. The plurality of contacts 4 are e.g. formed during assembly by deposited amounts of conductive adhesive (CA), or as an alternative by solder contact dots. The solar cells 2 are arranged in a regular grid pattern 8, e.g. comprising an array of 6 x 10 solar cells 2 per solar module 1 , wherein e.g. three strings of solar cells 2 are present. The strings are formed using contact paths 5 formed in the back contact sheet 3, e.g. using isolating scribe lanes 6 on the back contact sheet 3.

So in general terms as used throughout this document, a solar module 1 is provided as embodiments of the present invention, which comprises a back contact sheet 3 for connecting the plurality of solar cells 2 in one or more strings 5 (using isolation scribes 6), and a plurality of clusters 7 of back side contacts 4, each cluster 7 being associated with one of the plurality of solar cells 2 for providing electrical contact to the back contact sheet 3.

In Fig. 1 a schematic view is shown of a part of a solar module 1 according to an embodiment of the present invention. The lines 9 represent edges of a solar cell 2, which in this embodiment are rectangular cells 2. The plurality of contacts 4 associated with a solar cell 2 form a cluster 7 of back side contacts, wherein the cluster 7 is within the boundaries of the edges 9 of the solar cell 2. If all solar cells 2 were arranged at equal distances to each other (as customary in existing solar modules 1 , and even when e.g. round solar cells 2 are present), a regular grid pattern 8 would result. The regular grid pattern 8 is a rectangular grid pattern, defined by the shape and/or position of the individual solar cells 2 (e.g. by edges 9 in case of rectangular or polygonal cells, which are forming the regular grid pattern 8). If a solar module 1 is provided with at least three solar cells 2, two of the solar cells 2 can be seen as forming a regular grid pattern 8 if they are positioned next to each other at an equal distance dmin as shown in Fig. 1 , or in other words with a constant spacing (equal distance dmin) between adjacent edges 9. It is also clear that in the embodiment shown in Fig. 1 , the third solar cell 2' (the at least one of the plurality of solar cells 2') is positioned outside of the regular grid pattern 8 associated with a single one of the plurality of solar cells 2. The regular grid pattern 8 can thus be seen as a grid pattern dependent on dimensions of a 'standard' solar cell 2 making up the plurality of solar cells 2 in the solar module 1. The grid pattern 8 is made up of an array of rectangular areas, which is congruent to an array of associated solar cells 2. I.e. the regular grid pattern 8 has a pitch in the (perpendicular) x-and y-axis, conform a dimension in the x-, resp. y-axis of a single solar cell 2. The regular grid pattern 8 would be visible in the solar module also when all solar cells 2 of the module were positioned in a regular pattern, with a predetermined distance between adjacent solar cells 2 in the x- and y-direction. The pitch of the regular gird pattern 8 in a specific direction (x- or y-direction) is then equal to the x-, resp. y-direction dimension of the associated solar cell 2 plus a spacing distance. In alternative wording, the regular grid pattern 8 is defined as being associated with a pitch distance between centers of gravity of adjacent solar cells 2 (which terminology would also be applicable if the solar cells 2 have an irregular shape).

It is noted that of course due to manufacturing tolerances the exact interspacing of solar cells 2 in a solar module 1 may vary a little bit, but the general characteristics as explained herein still hold true.

Fig. 2 shows a schematic view of a back contact sheet 3 associated with the solar module 1 embodiment as shown in Fig. 1. Strings 5 of the solar module 1 are formed by providing the isolating scribe lanes 6 as shown to form contact fields 5 (which can also be seen as forming the strings 5 as described above), which connect positive contact points from a solar cell 2 to negative contact points from an adjacent solar cell 2.

Fig. 3 shows a composite view of the three layers of the solar module embodiment of Fig. 1 and 2, wherein at least one of the plurality of solar cells 2 of the solar module 1 is positioned outside of the regular grid pattern 8, and the back contact sheet 3 to contact the at least one of the plurality of solar cells 2 with the associated string of the one or more strings 5. In an

alternative embodiment the cluster 7 of back side contacts 4 is adapted locally to allow proper connection between two adjacent solar cells 2.

As shown in detail in Fig. 1 and Fig. 3 a cluster 7 of back side contacts 4 is bound by edges 9 of the associated solar cell 2, providing a reference point r of the associated solar cell 2 where two of the edges 9 cross. A distance dr between reference points r of the at least one solar cell 2' and an adjacent solar cell 2 is larger than a minimum distance dmin between edges 9 of solar cells 2 in the regular grid pattern 8 of the solar module 1. This structural variation of the positioning of the plurality of solar cells 2 in a solar module 1 provides the opportunity to obtain solar modules 1 with a different aesthetic view.

In one group of embodiments, the at least one of the plurality of solar cells 2' is rotated with respect to the regular grid pattern 8 over an angle a unequal to 90° (or multiples thereof), as shown in Fig. 1. Furthermore, the at least one of the plurality of solar cells 2' may be rotated with respect to the regular grid pattern 8 over an angle between 1 ° and 89°, e.g. between 2° and 88°. It is noted that the angle a can be positive or negative, and may vary for several of the plurality of solar cells 2 of a solar module 1. This would e.g. even make it possible to have a solar module 1 with a fan like arrangement of the plurality of solar cells 2, or with columns of solar cells 2 having an alternating left and right nutation of the solar cells 2. Fig. 4 shows a composite view of the three layers of a further exemplary embodiment of a solar module 1 having four solar cells 2, all with a similar angular displacement in view of the regular grid pattern 8. It is clearly shown that in this embodiment, the pattern of the contact fields 5 of the back contact sheet 3 are adapted from a prior art solar module back contact sheet 3.

Alternatively or additionally, the at least one of the plurality of solar cells 2' is translated with respect to the regular grid pattern 8 over a distance unequal to a single inter-cell distance dcell of the regular grid pattern 8 (see Fig. 1 ). This would allow to have a varying distance between solar cells 2 of a solar module 1 , possible in combination with the angular displacement, providing a wide variety of possible designs of solar cell arrangements in a solar module 1.

In view of the above description, it is clear that not just the at least one 2'of the plurality of solar cells is positioned outside of the regular grid pattern 8. Also the cluster 7 of back side contacts (which can be seen as one of the parts of the solar module 1 ) is likewise positioned outside of the regular grid pattern 8. In other words, the solar module 1 comprises a plurality of equal clusters 7 of back side contacts, which clusters 7 (associated with the solar cells 2) are arranged in an irregular pattern.

Fig. 5a shows a schematic view of one solar cell 2, having edges 9 which form the regular grid pattern 8 of a solar module. The reference point r is shown on one of the corners of the solar cell 2. Fig. 5b shows a schematic view of an embodiment wherein the at least one of the plurality of solar cells 2' is divided in two or more parts 2a, 2b sharing the associated cluster 7 of back side contacts 4. In the example shown, one part 2b (the right top corner of a solar cell 2') is cut from the entire solar cell (leaving the other part 2a in place), and moved away from the breaking line over a distance dt. If the distance dt is smaller than the minimum distance dmin as defined in relation to the regular grid pattern 8 of the embodiments described above, the same dimensions

of the solar module 1 can be maintained. It will however require to adapt the configuration of the contact fields 5 of the back contact sheet 3, as shown in the composite view of Fig. 6: To maintain the contact with (positive) back side contacts 4a of the split of part 2b, the additional contact fields 5a are provided (and similarly for the negative back side contacts 4b).

In the embodiment shown, the at least one of the plurality of solar cells 2' is split using a straight cut, but any form of cutting line can be made, as long as the sum of the two parts 2a, 2b is equal to the surface area of any of the other of the plurality of solar cells 2. E.g. the plurality of solar cells each have the same surface area allowing to still connect the solar cells 2 in strings 5 of the solar module 1.

In a further group of embodiment, the plurality of solar cells 2 each have the same dimensions. Using solar cells 2 having the same dimensions has the advantage of easier handling and assembly of a solar module 1. By using one of the embodiments above, it is still possible to obtain a wide variety of different solar module designs.

The plurality of solar cells 2 may comprise solar cells 2 having the shape of an entire wafer cell, a semi-cell, a quarter cell, a triangular cell, a rectangular cell or a round cell (i.e.

circular, oval, etc.). When all solar cells 2 in a solar module 1 have the same shape, it is possible to obtain a solar module 1 with a very aesthetic appearance.

In a further group of embodiments, the plurality of solar cells 2 comprise a combination of at least two types of solar cells 2, selected from the group of an entire wafer cell, a semi-cell, a quarter cell, a triangular cell, a rectangular cell, or a round cell (i.e. circular, oval, etc.). Combining different shapes of solar cells 2 provides an even further array of possible configurations of the solar module 1.

An arrangement which would be very advantageous in BIPV applications would be a brick type of arrangement of the solar cells 2, i.e. wherein the plurality of solar cells 2 comprises a plurality of spatially separated groups of similar shaped solar cells. Even further, the group of similar shaped solar cells may comprise at least two adjacent solar cells 2 of which two respective sides 9 are in contact with each other, i.e. having no inter-cell gap. An example of such a configuration is shown in the embodiment of the solar module 1 shown in Fig. 7. In a regular 6 x 10 configuration of a solar module 1 , the two middle rows are provided with split cells having two parts 2a, 2b, with a circular cut line. Furthermore, the two different parts 2a, 2b of adjacent solar cells 2' are arranged outside of the regular grid pattern 8, with their edges 9 aligned, thus forming five complete circles in the appearance of the solar module 1.

Further embodiments are envisaged by the present invention, wherein further modifications are made to the back contact sheet 3 before or during assembly of the solar module 1. E.g. the back contact sheet 3 is (partially) removed in a part of the solar module 1 where no solar cell 1 is present. This allows to e.g. create partially transparent solar modules 1 , which can be advantageous especially in BIPV applications. The removed part of the back contact sheet 3 is filled with a filling layer in a further embodiment. The filling layer may comprise one or more of: a colored sheet, a photo sheet, a logo sheet, a textile sheet, an item in a further group of

embodiments providing even further possible design variants. An empty part of the solar module 1 may e.g. even be filled with three dimensional items such as a dried flower.

The present invention embodiments have been described above with reference to a number of exemplary embodiments as shown in the drawings. Modifications and alternative implementations of some parts or elements are possible, and are included in the scope of protection as defined in the appended claims.