A laminated solar glazing and a method for production thereof

Abstract

The present invention relates to a laminated glazing (1) comprising at least two substrate sheets (11, 12), at least one solar cell assembly (2) with at least one solar cell string (21) with at least one photovoltaic solar cell (22), at least one end connector (23) at each end of the solar cell string (21), provided in between at least two interlayer (13).

Description

A LAMINATED SOLAR GLAZING AND A METHOD FOR PRODUCTION THEREOFFIELD OF THE INVENTION

[0001] The present invention relates to a laminated glazing, in particular a laminated solar glazing. More particularly, a laminated glazing comprising a solar cell assembly laminated inside the glazing and more particularly to techniques for its production. Solar vehicle glazing plays a crucial role in enhancing energy efficiency and sustainability by harnessing solar energy while maintaining safety and functionality.BACKGROUND OF THE INVENTION

[0002] The invention is primarily intended to be used in the production of automotive glazing but not limited to. The present invention relates to a glazing comprising solar cells laminated inside the glazing. Therefore, there is a need of electrical connections to the solar cells, the electrical connection is needed to be reliable and robust enough to survive after the lamination process.

[0003] In the state of the art, such electrical connections predominantly rely on high temperature soldering. Standard methods for preparing solar cell assemblies comprising interconnecting strings of crystalline silicon photovoltaic (PV) cells, i.e., solar cells are based on high temperature soldering (typically >180 °C) of flat conductive ribbons coated with low- cost solder alloys onto the end connectors of the solar cell strings. The solder alloys and soldering conditions (time, temperature, etc.) are carefully chosen so that reliable solder joints are formed between end connectors of the solar cell strings and the flat conductive ribbons that can survive subsequent lamination conditions (temperatures up to 170°C and pressures up to several bars) as well as long term operation in the field without degradation. Basically, conductive ribbon tapes are soldered to the end connectors of the solar cell strings, i.e., the solar cell strings to provide different layouts / topologies of solar cells. In the case of standard solar cell assemblies, the electrical connection is provided with the conductive tapes / strips / flat conductive ribbons commonly known as PV ribbons.

[0004] Standard laminated vehicle glazings include thermoplastic interlayers such as polyvinyl butyral (PVB), ethylene vinyl acetate (EVA) and many others. Thus, the method above cannot be directly performed onto the thermoplastic interlayer since the thermoplastic interlayers may melt or even burn during the high temperature soldering process. A first consequence of such drawback is that direct contact must be avoided with the thermoplasticinterlayer during the high temperature soldering operations. This leads to complex solutions such as placing of a temporary insulating barrier (e.g. Teflon bar) between the thermoplastic interlayer and the PV cell strings or lifting of PV cell strings either partially or fully to perform the soldering operations away from the thermoplastic interlayer to avoid direct contact before placing them back onto it, both solutions require more time and cost.

[0005] In the solution of lifting the solar cell strings for the soldering process which is the preferred solution up to now, there actually exists another lifting operation which is the layup operation, i.e., placing the solar cell strings from the stringing machine onto the thermoplastic interlayer. Individual solar cells are connected with each other in the stringing machine to make the solar cell strings, strings are one by n matrix of solar cells, n being an integer larger than 1. Therefore, multiple lifting operations may cause damaging of strings and also increase alignment needs.

[0006] Another consequence is that the conventional PV ribbons must be relatively flat and rigid to allow for accurate handling, shaping and positioning. This is typically achieved by pulling the PV ribbon from a round spool and stretching it mechanically to achieve sufficient flatness prior to cutting it or bending it to the correct dimensions. As a consequence, the completed solar cell assembly after interconnection (consisting of the solar cell strings and soldered PV ribbons) is typically too rigid to follow complex curvatures such as the ones encountered in laminated automotive glazing. As the solar cells are already thick and rigid, there is a need of flexibility in the electrical connection that compensates the rigidity of the solar cells. In addition, since there is no adhesion between the PV ribbons and the plastic interlayers prior to lamination, the PV ribbons are free to move during the subsequent assembly steps and in particular during the lamination process which can lead to defects like alignment issues or cell breakages.

[0007] In the automotive field, such glazings are for example used mainly for the roofs, and possibly for side windows including the quarter-lites and back-lites of vehicles. In particular, glazed roofs are increasingly being substituted for conventional metallic roofs, which form part of the body of vehicles. Also, it is more and more requested from designers and car manufacturers to have roofs with laminated glazing provided with a solar cell assembly to harvest the energy of sunlight entering inside the vehicle. However, the conventional methods mentioned above are not highly adaptable to automated processes due to their inherent complexity since different layouts / topologies of solar cell assemblies are requiredfor different glazings in addition to the issues listed above. Therefore, a lot of manual labor is required to fulfill the requirements of the automotive industry.

[0008] There are preexisting solutions like pre-laminate solar cell assemblies comprising of a solar cell matrix with the given layout and topology, end connectors ofwhich soldered with PV ribbons and laminated between polyolefin elastomer (POE) interlayers. Such prelaminates mostly comprise thin film solar cells folded onto each other as those type of solar cells are flexible. However, as mentioned automotive glazings such as roof, windshield, back- lite, quarter-lite and sidelite are generally bent to fit with the design of the car. The bent shape is more and more complex with high radius of curvatures and such pre-laminate solar cell assemblies with rigid PV ribbons cannot conform the curvatures of the glazing.

[0009] Therefore with the known techniques in the art, such laminated solar vehicle glazings encounter risks of solar cell damage, unconformity with the curvatures of glazings, multiple alignment requirements and increased difficulty in integration into automation processes thus providing such laminated glazing with a solar cell assembly is even more challenging.[OO1O]EP175517O describes a solar cell assembly having at least a solar cell and a reinforcing element that at least partially covers the solar cell and the reinforcing element is in the form of a sheet-like woven or knitted fabric or a film. The reinforcing element provides rigidity for the solar cell assembly.

[0011] AU2O191O12O5 describes solar cell modules in which the solar cells are arranged in a shingled manner, wherein each of the crystalline silicon solar cell strips are arranged such that the long edges of adjacent ones of the crystalline silicon solar cell strips overlap and are conductively bonded to each other in series via an electrically and thermally conductive adhesive.

[0012] It is also known from EP1154492 that a method of manufacturing a solar module for a vehicle describing the solar cells are positioned on the first lamination film and are connected to the connecting elements in a fixed position in electrical contact.

[0013] EP3776664 describes the production of end connectors as busbars for the solar cells and solar cell strings.

[0014] US9559233B2 describes an interconnect structure to connect solar cells to each other to provide a solar cell string.

[0015] US11894485B2 describes a wire bonding system configured to attach wires to a solar cell wafer comprising a movable platform that enables automated production.

[0016] US20180006602 describes how an external electrical connector is connected to a solar module. US10777691 describes busbar connection to back contact solar cells in a PV module.

[0017] US20150136207A1 describes a roof panel with an integrated PV module where stripshaped solar cells are connected to each other in series, forming a group of series-connected solar cell strips, with at least two groups connected in parallel by means of at least two busbars. While this approach can offer some advantages such as improved tolerance to partial shading, it presents numerous limitations. A first challenge with this approach is that parallel connections adds up the maximum currents of each group of cells. This can lead to significant power losses in the busbars and external cables as resistive losses are proportional to the square of the PV current generated at maximum power point. Alternatively, this requires the use of large cross-sections for the busbars (and cable connectors) taking up valuable space inside the roof panel or limiting the ability of the busbars to flex to follow glass curvatures. In addition, parallel connection requires each group of cells to have the same total voltage to minimize miss-matching losses. Furthermore, cutting the solar cells into narrow strips with a width of 10mm or below (to minimize the generated currents and improve surface coverage) damages the edges of the PV cells leading to power losses and higher risk of cell breakages, particularly during the assembly and lamination steps. Also, cutting the cells in narrow strips to form groups of 10 to 100 cells connected in series, quickly leads to groups of cells with different total voltages and hence higher miss-matching losses when connecting all groups in parallel. That is why it is more advantageous to use solar cells with a standardized square (or semi-square) format and to have the freedom to connect groups of series-connected cells into different electrical layouts depending on the customer requirements for the roof panel (maximum output currents and voltages, position of the busbars and connectors, etc.). Examples of standardized square or semi-square silicon solar cell formats offering a good compromise between manufacturing costs, electrical characteristics, and robustness include 125x125mm2, 182x182mm2, 210x105mm2, 105x105mm2among others. These are all significantly wider than the 10mm strip-shaped cells proposed. Examples of typical electrical layouts for PV modules include full-series, half-parallel, and full-parallel. Full-series layouts generally help minimize resistive losses and build up output voltages to a level that can be interesting to directly feed 48V batteries but suffer from worse tolerance to partial shading. Full-parallel layout offer the best tolerance to partial shading but suffer from high resistivelosses and low voltage outputs. Half-parallel layouts generally offer a compromise between the characteristics of full-series and full-parallel layouts.

[0018] US20230066735A1 describes a method for manufacturing a semi-finished free- formable PV module using a plurality of flexible PV elements consisting of a thin film PV stack on flexible carrier. Known flexible cells include PV cells based on a flexible plastic (or thin metal) carrier and thin film deposition technologies such as copper indium gallium selenide (CIGS), cadmium telluride (CdTe), amorphous silicon (aSi), organic photovoltaics (OPV), and perovskites (PVK). On the contrary, standard thick film PV cells are based on a thick, rigid, and brittle substrate material such as monocrystalline silicon (Si), germanium (Ge) or gallium arsenide (GaAs). The PV module in US20230066735A1 is formed by folding the side-portions forming the front contactable second polarity front terminal at least in part back along the back surface of the flexible thin film PV element to form a back contactable second polarity back terminal; and disposing a plurality of flexible electrically conductive wiring elements in a pattern adapted to match a layout of the plurality of flexible thin film PV elements. A first challenge with this approach is that each flexible PV element needs to have current collecting elements disposed on both sides that extend significantly beyond the sides of the thin film PV stack to allow subsequent folding and interconnection. This adds a lot of complexity (and hence significant costs) to the manufacturing process. Further, significant space (well above 2 mm) is required between each thin film element to allow folding of the side portions and subsequent interconnection using the flexible electrically conductive wiring elements. This large space leads to lower power density (in W / m2) as the active PV area per m2 is reduced and to worse aesthetics as the interconnection elements are visible from outside in between each thin film PV elements. On the contrary, standard and highly automated interconnection methods for connecting thick-film PV cells such as silicon PV cells typically allow to minimize the gaps between each cell to 2 mm or below (with even 0 mm being possible with gapless interconnection technologies). While such narrow gaps between each silicon PV cells allow to maximize the active area and hence the power density, it can become a challenge to follow the complex 3D curvatures of typical automotive glazing elements such as roofs. That is why it is advantageous to keep a minimum gap between each silicon PV cells of 0.5 mm to 2 mm and to increase the flexibility of the electrical conducting elements between each silicon PV cells since they are more rigid than the typical flexible cells mentioned above.

[0019] US10454416 describes an automotive roof made of other materials than glass that the roof has bosses for alignment and fixing the solar cells. Therefore, the solar cells and the electrical connections require thru-holes in order to be installed onto the bosses on the roof. Although the solution provided seems to solve the lamination issues mentioned above, this solution requires a roof not made of glass, thus it is not compatible with glass roofs and conventional lamination processes.

[0020] Unfortunately, the solutions provided in the prior art for the issues of electrical connection are requiring extra steps in the production or usage of extra features which means extra time and cost for the production. Alternative solutions provided in the prior art on the other hand propose simple and cheap solutions that create other issues like overheating due to partial shading and etc. Thus, providing an affordable laminated glazing with solar cell assembly for the final customers cannot be a widely spread application.

[0021] Supplementary to the long production times and high cost, there is a risk of jeopardizing the glazing because of the probability of damaging the solar cell strings in the multiple alignment operations. In addition, since the commonly used PV ribbons are rigid and have to be applied on a straight line, the utilization of the available area is limited.SUMMARY OF THE INVENTION

[0022] The goal of the present invention is to provide a glazing having a solar cell assembly laminated inside and with an affordable and defect-free method of production to eliminate the aforementioned problems. The present invention aims to address specific challenges related to glazing materials, manufacturing processes, and integration into vehicle design.

[0023] The present invention provides a glazing with a solar cell assembly that may be integrated into a bent shape glazing utilizing almost all available area without defects. More specifically, the present invention provides flexible conductive electrical connections for the end connectors of the solar cell strings providing the such electrical connections suitable for automated production regardless of the layout or the topology of the solar cell assembly. Moreover, the present invention allows production of any type of layout and / or topology of the solar cell assembly provided on the roof glazing possible and even in an automated way. Even more specifically, the present invention provides fixated conductive electrical connections that eliminates multiple alignment processes.

[0024] It is therefore an objective of the present invention to enhance solar vehicle glazing by addressing these critical aspects, revolutionizing the field with improved efficiency and reliability.

[0025] The laminated solar glazing of the present invention comprises at least one cross connector providing electrical connection to the end connector(s) provided at the each end of solar cell strings. The cross connectors of the present invention provides electrical connection between the end connectors of different solar cell strings or between the busbars and the end connectors of solar cell strings. The cross connectors of the present invention enables the automation of the production of such laminated solar glazings regardless of the layout or the topology of the solar cell assembly. The cross connector may be shaped in any desired shape that the said can also be used carrying the current out of the laminated glazing. The cross connector may be fixed onto the interlayer to ease the alignment of solar cells. The cross connectors of the present invention provides enough flexibility in production of laminated solar glazing with rigid solar cells and eliminates breaking or shattering of solar cells due to high rigidity during the lamination process compared to the conventional busbars used in such applications.

[0026] In one of the preferred embodiments of the present invention, the cross connectors connected to the end connector(s) comprise a soft-core metallic layer to provide flexibility. Providing the flexible cross connectors of the present invention allows the solar cell assembly to follow the contour of the glazing, therefore securing the electrical connection by reducing electrical losses to the end connectors and such flexibility also allows facilitation of different layouts or topologies for the solar cell assembly.

[0027] I n one another preferred embodiments of the present invention, the cross connectors connected to the end connector(s) comprise low temperature solder alloys that eliminate unnecessary process steps like temporary raising of the solar cell strings for high temperature soldering, assuring the correct alignment of the solar cell assembly inside the glazing and obtaining a defect-free lamination process and reducing the costs by elimination of soldering step due to activation with pressure and temperature in autoclave lamination to facilitate ease of establishing electrical connection.

[0028] I n one another preferred embodiments of the present invention, the cross connectors connected to the end connector(s) comprise an adhesive layer to be able to fix / anchor thecross connectors over the interlayer to fix the alignment issues mentioned above and also facilitating the alignment by being alignment reference in the automated process.

[0029] The method of the present invention for producing a laminated solar glazing of the present invention comprises the steps of providing the cross connectors on or below the end connectors, i.e., fixing / adhering / attaching the cross connectors onto the first interlayer or the second interlayer during the production of the laminated solar glazings. The cross connectors are pre-cut in desired shape and length that the automation robots pick the cross connectors and place them onto the interlayer or onto the end connectors of the solar cell assembly, and any layout or topology is feasible by simply programming the automation. The said production method eliminates any extra alignment steps since the cross connectors providing more than one function, moreover enables ease of achieving an aesthetically pleasing high quality solar glazing with reducing manual labor and costs.

[0030] More particularly, the present invention concerns a method for production of a laminated solar glazing comprising at least: a. a first sheet having an outer (Pl) and an inner (P2) faces, b. at least one solar cell assembly / unit with at least one solar cell string with at least one photovoltaic solar cell, c. at least one end connector at each end of the solar cell string, d. a second sheet having an outer (P4) and an inner (P3) faces, e. two interlayers as bonding layers in the lamination process wherein the cross connectors providing electrical connections to at least one end connector.

[0031] In addition, the usage of cross connectors for the electrical connection is allowing a reduction in production time by eliminating unnecessary process steps like soldering or anchoring. Overall, the flexible cross connectors of the present invention results in reductions in both production times and costs, moreover provides stable operation by facilitating reproducible current carrying capacity.

[0032] The foregoing detailed description is given primarily for clearness of understanding and no unnecessary limitations are to be understood therefrom for modifications can be made by those skilled in the art upon reading this disclosure and may be made without departing from the nature of the invention.BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The invention will now be described further, by way of examples, with reference to the accompanying drawings, wherein like reference numerals refer to like elements in the various figures. These examples are provided by way of illustration and not of limitation. The drawings are a schematic representation and not true to scale. The drawings do not restrict the invention in any way. More advantages will be explained with examples. A better understanding of the present invention will be added upon reference to the following description in conjunction with the accompanying drawings.

[0034] FIG.1 is a partial view of a vehicle with glazing.

[0035] FIG.2 is a schematic view of the laminated glazing according to one embodiment of the present invention.

[0036] FIG.3 is a schematic view of a solar cell assembly according to one embodiment of the present invention.

[0037] FIG.4 is a schematic view of a solar cell assembly according to one embodiment of the present invention.

[0038] The elements illustrated in the figures are numbered as follows:1. Glazing11. First sheet12. Second sheet13. Interlayer2. Solar cell assembly21. Solar cell string22. Individual solar cell23. End connector24. Electrical component3. Cross connectorDETAILED DESCRIPTION OF THE INVENTION

[0039] The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims.

[0040] While some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments aremeant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0041] As used herein, spatial ordirectional terms, such as "inner", "outer", "above", "below", "top", "bottom", and the like, relate to the invention as it is shown in the drawing figures. However, it is to be understood that the invention can assume various alternative orientations and, accordingly, such terms are not to be considered as limiting. Further, all numbers expressing dimensions, physical characteristics, processing parameters, quantities of ingredients, reaction conditions, and the like, used in the specification and claims are to be understood as being modified in all instances by the term "about". Accordingly, unless indicated to the contrary, the numerical values set forth in the following specification and claims are approximations that can vary depending upon the desired properties sought to be obtained by the present invention.

[0042] Moreover, all ranges disclosed herein are to be understood to be inclusive of the beginning and ending range values and to encompass any and all subranges subsumed therein. For example, a stated range of "1 to 10" should be considered to include any and all subranges between (and inclusive of) the minimum value of 1 and the maximum value of 10; that is, all subranges beginning with a minimum value of 1 or more, e.g., 1 to 6.1, and ending with a maximum value of 10 or less, e.g., 5.5 to 10. Further, as used herein, the terms "deposited over" or "provided over" mean deposited or provided on but not necessarily in surface contact with. For example, a coating "deposited over" a substrate does not preclude the presence of one or more other coating films of the same or different composition located between the deposited coating and the substrate.

[0043] Where the term "comprising" is used in the present description and claims, it does not exclude other elements or steps. Where an indefinite or definite article is used when referring to a singular noun e.g., "a" or "an", "the", this includes a plural of that noun unless something else is specifically stated. In this document, "configured to (or set to)" may be interchangeably used in hardware and software with, for example, "appropriate to", "having a capability to", "changed to", "made to", "capable of", or "designed to" according to a situation. In any situation, an expression "device configured to do" may mean that the device "can do together with another device or component.

[0044] Furthermore, the terms first, second and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein. When it is described that a constituent element (e.g., a first constituent element) is "(functionally or communicatively) coupled to" or is "connected to" another constituent element (e.g., a second constituent element), it should be understood that the constituent element may be directly connected to the another constituent element or may be connected to the another constituent element through another constituent element (e.g., a third constituent element).

[0045] I n the following description, unless otherwise specified, expression "substantially" or "around" or "proximity" or "close to" preferably mean to within 10%, preferably to within 5% i.e., in this context the terms should be understood as in the range of ± 10%, even more ± 5%. Tolerance may be selected depending on the nature of the intended applications.

[0046] A vehicle should be understood as any conveyor that transfers anything from point a to point b which includes any land, air or sea vehicles like car, van, lorry, motorbike, bus, tram, train, drone, airplane, helicopter and the like.

[0047] In the following description, unless otherwise specified, expression "solar cells assembly", "solar cell assembly", "solar cell matrix", "solar panel", "photovoltaic (PV) cells assembly", "photovoltaic assembly" are used interchangeably, expression "solar cell", "PV cell", "photovoltaic cell" are used interchangeably, further expression "electrical component", "circuitry element", "bypass diode", "wire harness" and "cabling" are used interchangeably, further expression "sheet", "substrate sheet", "glass sheet" and "plastic sheet" are used interchangeably.

[0048] The present invention introduces improvements to a laminated solar glazing (1) comprising at least two substrate sheets (11, 12), and at least two interlayer (13) as bonding layer, at least one solar cell assembly (2) with at least one solar cell string (21) with at least one photovoltaic solar cell (22) which is preferably wafer-based, and at least one end connector (23) at each end of the solar cell string (21) and the solar cell assembly (2) is laminated inside the glazing (1) in between two sheets (11, 12). Before going into the detailsof the present invention, definitions for glazing (1), structure of the proposed glazing (1) will be explained herein.

[0049] The laminated solar glazing (1) may be used as a vehicle glazing or as a glazing for buildings and / or architectural purposes or anywhere where such glazing is required. In the automotive industry, such glazings are used as windshields, backlites, sidelites, roofs, rear- door-fixes or quarter-lite-fixes.

[0050] The glazing (1) is comprising a first substrate sheet (11) having an outer (Pl) and an inner (P2) faces, a second substrate sheet (12) having an outer (P4) and an inner (P3) faces. The substrate sheets (11, 12) may be glass sheets as conventional vehicle glazing, however other materials like plastic, thermoplastic polymers and so on can be used as the substrate sheets. According to the invention, the glass may be a glass of soda-lime-silica, aluminosilicate or borosilicate type, and the like, or the plastic may be PC, PET, PMMA, etc. For the sake of the invention, the material or other properties (thickness, number of substrate sheets, relative sizes) of the substrate sheet (11, 12) is not utmost important, the glazing (1) may be made of combination of different substrate sheets (11, 12). Thus the composition of the glazing (1) is not crucial for the purpose of the present invention. Moreover, the thicknesses of the sheets (11, 12) are also not crucial for the purpose of the present invention.

[0051] The glazing (1) is comprising two interlayers (13) as bonding layer for the substrate sheets (11, 12). The interlayer (13) may be one of the conventional interlayers used in lamination processes, examples of the interlayer (13) are EVA, TPO, POE, PVB, TPU, Ionomers, and etc. which are widely known and used in both automotive and architecture industry. For the sake of the invention, the material or other properties of the interlayer (13) is not utmost important, the two interlayers (13) of the glazing (1) may be two different interlayer.

[0052] The glazing (1) is preferably curved. The term "curved" is defined by the following criteria: "the curved laminated glazing has at least 50% of its total surface area having a minimum radius of curvature (R min) comprised between 50 and 15000 mm". Therefore, as understood from the definition of curved surface, the curvature of the glazing (1) may be in only one direction (2D) or in at least two direction (3D) in terms of the orientation as long as the definition of curvature described above satisfied. Preferably, the first and / or the second substrate sheets (11, 12) are bent in a previous step before providing a solar cell assembly (2) over at least one surface of the first and / or the second substrate sheets (11, 12), i.e., before the lamination process which will be described below. The curvature values of the firstsubstrate sheet (11) and the second substrate sheet (12) may be in line with each other, it has to be understood that the curvature values might not be the same. Likewise, the first sheet (11) may have a low curvature and the second sheet (12) is flat, this type of glazing (1) can also be counted curved glazing (1) as long as it satisfies the criteria described. However, the curvature of the glazing (1) is not crucial for the present invention.

[0053] According to the invention, the term "laminated" refers to a step of providing a layered structure in which the solar cell assembly (2), and one or more sheets (11, 12) are separated by an interlayer (13) extending across substantially the entire interface between the solar cell assembly (2) and the sheets (11, 12). In the preferred embodiment, the lamination is realized by sandwiching the solar cell assembly (2) in between two interlayer (13), the two interlayer (13) may be same interlayer (13) or different types of interlayers (13) depending on the need. The interlayer (13) is used as a bonding layer during the lamination process. In the preferred embodiment, the lamination process is a classical lamination process including autoclave a glazing (1).

[0054] The glazing (1) is comprising at least one solar cell assembly (2) being positioned between the faces 2 (P2) and 3 (P3), where it can be protected from damage. The solar cell assembly (2) is composed of at least one solar cell string (21) and the solar cell string (21) is composed of at least one solar cell (22). The individual solar cells (22) may be any type of solar cells (22) available and suitable for laminating inside a glazing (1), in the preferred embodiment the solar cells are rigid solar cells. The solar cell string (21) is at least two series- connected solar cells (22) using flat or round metallic wires running across each solar cell (22), particularly made of multiple solar cells (22) connected each other end to end. The connection inbetween adjacent solar cells (22) is not significant. The solar cell assembly (2), particularly solar cell matrix, is made of at least one solar cell string (21), more specifically multiple solar cell strings (21) connected in series or parallel or combination of both. By "solar cell" it is meant a photovoltaic cell, is an electronic device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physical phenomenon. It is very well known that the solar cells (22) can be c-Si, a-Si or thin-film solar cells or combinations thereof, in the preferred embodiment, the solar cells (22) are wafer-based solar cells since those are more efficient than thin-film solar cells. In a particular arrangement, the solar cell assembly (2) is composed of n*m matrix of solar cells (22), n being number of solar cell strings (21) and m being number of solar cells (22) in a solar cell string (21), further wherein n>l and m>l.However, solar cell assembly (2) may also have an irregular matrix design depending on the shape of the glazing and the usable area for such glazing, i.e., solar cell assembly (2) may comprise solar cell strings (21) with different number of solar cells (22).

[0055] The glazing (1) is comprising at least one end connector (23) at each end of the solar cell string (21). The end connector (23) is used for extracting power from the solar cell strings (21). The end connectors (23) are electrically connected at each end of the solar cell strings (21) with a metallic core layer having a thickness between 1 and 1000 microns, ideally between 10 and 300 microns, even more ideally between 30 and 150 microns to provide sufficient flexibility. The end connectors (23) function as current carrying elements to provide the solar cell string (21) to be electrically connected. The end connectors (23) have a width that is between 1 and 100 mm, ideally between 5 and 30 mm to provide sufficient current carrying capacity, the width defined in the parallel axis of the solar cell string (21). The length of the end connector (23) can be customized according to the needs of the application, the length is defined in the perpendicular axis of the solar cell strings (21). In the preferred embodiment of the present invention, the end connector (23) is a flat strip tinned copper wire to provide protection from corrosion.

[0056] I n a preferred embodiment of the present invention, the maximum length of the end connectors (23) is the sum of the length of a solar cell (22) and two times the gap between two adjacent solar cell strings (21), particularly (Lmax < Length +2 *Gap). The length is defined in the perpendicular axis of the solar cell string (21). With maximum length defined in this embodiment, the length of the end connector (23) facilitates production of any layout and topology in an automated way. The solar cell strings (21) are laid out based on the desired layout and the end connectors (23) are connected based on the desired topology thanks to the present invention.

[0057] According to examples of the present invention, the Fig.l and Fig. 2 show a laminated automotive roof; the roof is intended to be fixed on the vehicle's body. It is understood that the invention is not limited to a roof and in another preferred embodiment of the present invention, the laminated glazing (1) can be used in any glazing for a vehicle and in another preferred embodiment of the present invention, the laminated glazing (1) can be used in outside of automotive industry, i.e., anywhere where a laminated glazing (1) is needed.

[0058] The glazing (1) as shown in Fig.2 as an embodiment of the present invention comprises a first sheet (11) having an external / outer surface (Pl) and an internal / inner surface (P2), anda second sheet (12) having an inner surface (P3) and an outer surface (P4). Such glazing (1) is laminated. The first sheet (11) of the glazing (1) is that sheet in contact with the exterior of the vehicle. The second sheet (12) is that sheet in contact with the inner space of the vehicle. However, as explained above, the ordering can be changed and also the glazing (1) can be a triple glazing or any kind of glazing with at least two sheets (11,12).

[0059] Thus, the invention relates to any glazing (1), whether tempered, curved or not, whether for a vehicle or a building, that comprises a solar cell assembly (2) with end connectors (23) to extract power from the solar cell assembly (2), and the glazing (1) comprises a bonding interlayer (13) for lamination as described above, the bonding layer can be any interlayer (13) material suitable for traditional lamination process. Achieving such configuration of the glazing (1) with the solar cell assembly (2) may be accomplished in any method, the present invention is related to form a reliable and conductive joints and yet flexible electrical connection for the solar cell assembly (2) inside the glazing (1).

[0060] The glazing (1) of the present invention comprises at least one cross connector (3) connected to at least one end connector (23) in order to facilitate the electrical connection from the said end connector (23) to another end connector (23) or to a busbar (not shown) or to an external wire harness, i.e., the cross connector (3) being adapted to establish an electrical connection with an end connector (23) of an adjacent solar cell string (21) or at least one busbar or external wire harness. The cross connectors (3) are used to connect the end connectors (23) of the solar cell strings (21) to realize the solar cell assembly (2) in any topology, i.e., usage of cross connectors (3) give the freedom and flexibility of designing solar cell assembly (2) for a particular glazing in a very affordable way with respect to the usage of conventional PV ribbons, thus the present invention enables use of standard solar cell strings in any layout and topology inside any glazing regardless of its shape with desired output parameters in an automated production way. Furthermore, the cross connectors (3) of the present invention enables the use of commercial solar cells (22) with standard end connectors (23) without a need of modification, i.e., less cost and time in production. The cross connectors (3) may be used to connect the end connectors (23) directly to a power line / external wire harness, thus the cross connectors (3) may eliminate the use of busbars.

[0061] In one embodiment of the present invention, the cross connector (3) is a flexible flat foil connector. The flexible flat foil connectors are widely used in laminated glazings since they are compatible with being laminated. The cross connectors (3) are designed from flat foilconnectors in different shapes to provide electrical connection between the end connectors (23) and / or between end connectors (23) and power line / busbars, thereby facilitating a more secure electrical connection and defect-free lamination process and also automated production. The cross connector (3) being a flat foil connector also provides flexibility that the stack before lamination as being flat and after lamination it requires some elements to be stretched due to curved nature of glazing since the solar cells cannot provide the required flexibility, i.e., the cross connector of the present invention provides compensation for the rigid solar cells. The cross connectors (3) may overlap with the end connectors (23) in order to secure the electrical connection and providing the said connection at ease that gives more tolerances for the automated production.

[0062] In another embodiment of the present invention, the cross connectors (3) are comprising a soft-core metallic layer. The soft-core metallic layer ensures the cross connector (3) being flexible enough to provide a reliable electrical connection. In technical aspect, the soft core metallic layer should be understood as the yield strength of the cross connector (3) is below 120 MPa, more specifically below 80 MPa, even more specifically below 40 MPa. Such ultra-low yield strength enables the stress being relieved from the solar cell assembly(2). Conventional materials such as copper and aluminum-copper alloys are preferred for the cross connectors (3), in some embodiments cross connector (3) may be tinned to protect from corrosion. In addition to the reliability, the soft-core metallic layer enables the cross connectors (3) to be applied in a curved manner but not as a straight line, i.e., allows cross connector (3) to be in any shape. In a version of this embodiment, the soft-core metallic layer can also be used as an adhesive layer by simply heating of the soft-core metallic layer that the soft-core metallic layer sticks to the interlayer (13), therefore eliminating the need for bosses provided on the substrate sheets (11, 12) that the cross connectors (3) enables glass being used as a substrate sheet (11, 12). Thanks to the flexible nature of the cross connectors (3), the shape of the glazing (1) does not need to be rectangular but any shape and the cross connectors (3) may follow any contour on the glazing (1) allowing efficient utilization of the glazing (1) area.

[0063] In another embodiment of the present invention, at least one of the cross connectors(3) is comprising an electrically conductive layer that can be activated with pressure and temperature, particularly a low temperature solder alloy. Such an electrically conductive layer provides the electrical connection to the solar cell assembly (2). The electrically conductivelayer is preferably on the inner side of the cross connector (3), i.e., the side facing the end connectors (23). In a preferred version of this embodiment, the electrically conductive layer is a low temperature solder alloy and more preferably a lead-free solder alloy since the usage of lead is banned in many jurisdictions. Application of pressure and / or temperature over the said conductive layer can be realized during the lamination process since the solar cell assembly (2) is already anchored / fastened in between the two sheets (11, 12).

[0064] In another embodiment of the present invention, at least one of the cross connectors (3) is comprising a pressure sensitive adhesive, i.e., comprising an adhesive on at least one face thereof. The adhesive may be applied on both sides of the cross connector (3) like double-sided adhesive tapes, more particularly on the back side facing the interlayer (13), to be used as a backing layer, i.e., at least one adhesive backing layer. The adhesive serves the purpose of fixing / attaching the solar cell strings (21) and its end connectors (23) onto the interlayer (13) before the lamination process, ensuring protection for the alignment of the solar cell assembly (2) on the glazing (1). By fixing the cross connector (3) onto the interlayer (13) via the adhesive and aligning the end connectors (23) to overlap with the cross connector (3), the alignment of the solar cell assembly (2) is locked, i.e., the cross connector (3) enables anchoring for the solar cell assembly (2). With this embodiment, it is ensured that the solar cells (22) are kept in the clear / transparent part of the glazing (1) and moreover the area of glazing (1) can be efficiently used since the alignment tolerances are minimized.

[0065] In another embodiment of the present invention, at least one of the cross connectors (3) have a thickness between 1 and 1000 microns, more preferably between 10 and 300 microns, even more preferably between 30 and 150 microns to provide sufficient flexibility. Providing thinner cross connectors (3) and combination of other embodiment allows usage of only one layer of cross connectors (3), thereby eliminating potential issues in the lamination process.

[0066] In another embodiment of the present invention, the width of the cross connectors (3) ranging between 1 mm to 100 mm, preferably 5 mm to 30 mm, even more preferably 5mm to 20mm. More particularly at least one of the cross connectors (3) have a width of at least the width of the gap between two adjacent solar cells (22). The maximum width of the cross connectors (3) is preferably less than the width of the solar cells (22), the width is defined in the perpendicular axis with respect to the solar cell string (21). Thus the cross connectors (3) may be like a patch to connect adjacent end connectors (23) and provide acost and time effective connection solution but also a cosmetically appealing design, especially when the cross connector (3) connects two adjacent end connectors (23).

[0067] The features described above for the cross connectors (3) enable integration of solar cells into the glass glazings with various advantages such as the flexibility required during lamination and prevention of solar cell breakage and maximization of the usable area for solar electricity generation and ability of automation of production and aesthetically pleasing design. Moreover, all these advantages are achieved in a cost effective way that both the material costs and production costs are kept unchanged or even lowered.

[0068] In another embodiment of the present invention, at least one cross connector (3) is made from the same material as the end connectors (23), preferably copper. The cross connector (3) being the same material as the end connector (23) provides a stable current flow without additional resistance build up and such an embodiment ensure the electrical resistance remain constant among all the end connectors (23), thereby enabling constant current flow from / to each end connector (23).

[0069] In a different embodiment of the present invention, the cross connectors (3) and / or the end connectors (23) have at least one stress relieving feature, such features may include punch-holes or folds or cuts allowing expansion / contraction or any other means providing stress relieving. Since the thermal expansion of the different element inside the glazing are different than each other, mechanical stress is build up during the lamination or transportation of the glazing or the usage on the vehicle due to the temperature changes and / or vibrations. It is also preferred that the thickness of the cross connectors (3) and / or the end connectors (23) are kept minimum as possible to provide flexibility, i.e., a stress relieving feature and thanks to the introduction of cross connectors (3) for the solar cell assembly (2), the width or length of which can be adjusted accordingly to compensate the loss in the current carrying capacity due to low thickness.

[0070] In another embodiment of the present invention, at least one of the cross connectors (3) is connected to an electrical component, i.e., a circuitry element (24). The other circuitry components / elements (24) may be flat connectors, Kapton connectors, FPC connectors, diodes, resistors but not limited to. The other required circuitry components can be connected / attached / fixed via the cross connectors (3). More particularly the cross connector (3) provides electrical connections for bypass diodes. In a specific version of this embodiment,a bypass diode is integrated into a cross connector (3) and the cross connector (3) electrically connects two adjacent end connectors (23).

[0071] In a preferred embodiment, the glazing (1) comprises multiple cross connectors (3) that the cross connectors (3) electrically connects end connectors (23) depending on the intended topology and also other electrical components (24) and also connect end connectors (23) to busbars or power line. The cross connectors (3) having low temperature solder alloy and soft metallic core and also adhesive on at least one side / face enables the cross connectors (3) to be used as alignment and anchoring means for the solar cell assembly (2) before the lamination step and eliminates the need of high temperature soldering without increasing the total thickness of the solar cell assembly (2).

[0072] In one another embodiment of the present invention, the glazing (1) comprising a black enamel band (not shown in figures) around the glazing edges and the cross connectors (3) and end connectors (23) are at least partially hidden underneath the black enamel band. It is very common in the automotive industry to apply black enamel band around the glazing edges for many practical reasons and application of such black bands, the material to be used are widely known.

[0073] By the cross connectors (3) of the present invention, achieving a larger usable area for the solar cell assemblies (2) became possible with different layouts for a same-size glazing (1) and the production can be realized as automatized thanks to the cross connectors (3). Therefore, in addition to the reliable electrical connection with less loss and robust operation, more energy can be harvested from light, especially from the sun through the glazing (1).

[0074] In the method of the present invention for production of a laminated glazing (1) comprising at least two substrate sheets (11, 12), a solar cell assembly (2) laminated in between two interlayer (13) comprising the steps of; a) providing the first substrate sheet (11), b) providing an interlayer (13) onto the first substrate sheet (11), c) providing the cross connectors (3) or the solar cell strings (21) onto the interlayer (13), d) providing the solar cell strings (21) or the cross connectors (3) depending on the previous step provided that the cross connectors (3) aligned with the end connectors (23), e) providing the second interlayer (13) onto the stack prepared in previous steps,f) providing the second substrate sheet (12) onto the second interlayer (13), g) laminating the stack prepared in previous steps.Thanks to the cross connectors (3) of the present invention forming series and / or parallel connections between each of the solar cell string (21) in the matrix, steps c) and d) are realized in an automated way that the whole production can be automatized without defects such glass breakage, solar cell cracking, miss-alignments of components, etc. After the interlayer (13) provided onto the first substrate sheet (11), prefabricated solar cell strings (21) can be carried over the interlayer with automation and since thanks to the cross connectors (3) of the present invention, there is no need to lift the solar cell strings (21) up and down for soldering. The cross connectors (3) may be provided after step b) that the solar cell strings (21) may be aligned accordingly with respect to the cross connectors (3). In the other version, the solar cell strings (21) are provided into the position onto the interlayer (13) and then the cross connectors (3) may be used to anchor the solar cell strings (21) in place. In a different version of the embodiment, the cross connectors (3) can also be used to make electrical connections between the solar cells (22) and other components such as bypass diodes, resistors, cables, flat foil connectors, etc.

Claims

CLAIMS1. A laminated solar glazing (1) comprising at least two substrate sheets (11, 12), at least one solar cell assembly (2) with at least one solar cell string (21) with at least one photovoltaic solar cell (22) and at least one end connector (23) at each end of the solar cell string (21) for extracting power from solar cells (22), provided in between at least two interlayers (13), characterized in that at least one cross connector (3) connected to at least one end connector (23), being adapted to establish an electrical connection with an end connector (23) of an adjacent solar cell string (21) or at least one busbar or external wire harness / power line.

2. A laminated solar glazing (1) according to claim 1, characterized in that the cross connector (3) being a flexible flat foil connector.

3. A laminated solar glazing (1) according to any preceding claims, characterized in that the cross connector (3) comprising a soft metallic core.

4. A laminated solar glazing (1) according to any preceding claims, characterized in that the cross connector (3) comprising a low temperature solder alloy.

5. A laminated solar glazing (1) according to any preceding claims, wherein the cross connector (3) comprising an adhesive on at least one face thereof.

6. A laminated solar glazing (1) according to any preceding claims, characterized in that the thickness of the cross connector (3) ranging between 1 pm to 1000 pm, preferably 10 pm to 300 pm, more preferably 30 pm to 150 pm.

7. A laminated solar glazing (1) according to any preceding claims, wherein the width of the cross connector (3) ranging between 1 mm to 100 mm, preferably 5 mm to 30 mm, even more preferably 5mm to 20mm.

8. A laminated solar glazing (1) according to any preceding claims, wherein the end connector (23) having similar properties of the cross connector (3).

9. A laminated solar glazing (1) according to any preceding claims, wherein the maximum length of the end connector (23) is sum of the length of a solar cell (22) and two times the gap between two adjacent solar cell strings (21).

10. A laminated solar glazing (1) according to any preceding claims, wherein the cross connector (3) also connects other electrical components (24).

11. A laminated solar glazing (1) according to any preceding claims, wherein an electrical component (24) integrated onto the cross connector (3), and the said cross connector(3) connects two end connectors (23).

12. A laminated solar glazing (1) according to any preceding claims, wherein n being number of solar cell strings (21) and m being number of solar cells (22) in a solar cell string (21), further wherein n>l and m>l.

13. A laminated solar glazing (1) according to any preceding claims, wherein the laminated solar glazing (1) comprising multiple cross connectors (3), and each cross connector (3) configured to function as a bridge between two adjacent end connectors (23) or carrying current out through the cables or hosting to a bypass diode, wherein the bypass diode being other electrical component (24).

14. A method for production of a laminated solar glazing (1) according to any preceding claims comprising at least two substrate sheets (11, 12), a solar cell assembly (2) laminated in between two interlayer (13) comprising the steps of; a) providing the first substrate sheet (11), b) providing an interlayer (13) onto the first substrate sheet (11), c) providing the cross connectors (3) or the solar cell strings (21) onto the interlayer (13), d) providing the solar cell strings (21) or the cross connectors (3) depending on the previous step provided that the cross connectors (3) aligned with the end connectors (23), e) providing the second interlayer (13) onto the stack prepared in previous steps, f) providing the second substrate sheet (12) onto the second interlayer (13), g) laminating the stack prepared in previous steps.

15. A method for production of a laminated solar glazing (1) according to claim 14, wherein providing other electrical components (24) before step e) provided the other electrical component (24) aligned with the cross connector (3).

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