DE102011079498A1 - Solar cell module for use on roof for forming solar cell arrangement, has bus bars cast in injection molded housing together with solar cells, and including contact elements, which are placed in edge regions of housing - Google Patents

Abstract

The module (20) has an injection molded housing (22) encapsulating solar cells (23) and formed by casting. The housing includes a front housing part (22a) over a front side of the cells, where the part is permeable for sunlight. Bus bars (21) are cast in the housing together with the solar cells. The bus bars include contact elements e.g. plug contacts, which are placed in edge regions of the housing. A rear housing part (22b) is made of high-stable plastic. The front housing part is made of high-grade transparent plastic. The housing is made of polymethyl methacrylate (PMMA) or polycarbonate. An independent claim is also included for a solar cell arrangement.

Description

The invention relates to a solar cell module for forming a solar cell array of a plurality of solar cells and a solar cell array formed from such blocks.

State of the art

In the production of solar modules according to the current state of the art, the individual (mono- or polycrystalline) cells first, as in 1 sketched, interconnected to so-called strings. Here, thin metal bands connect 1 each (not separately designated) front contacts of a solar cell 3 with the back contacts of the next one, so that all (eg 10) cells of a string are connected in series. Several strings are then installed, for example by lamination in a glass-plastic composite, to form a module. Shown is in 1 a string of three cells with back contacts 5 ; In practice, the strings consist of about 10 cells.

A major disadvantage of the method described above is that the individual cells from the time of interconnection to a string are difficult to replace. This is a problem not only during operation, but also during production, as the interconnection represents a very early process step. When soldering the tapes, when handling robots and laminating under high pressure and at high temperatures, the extremely thin and fragile cells are repeatedly exposed to mechanical and thermal stresses, a problem that will be exacerbated in the future by thinner cells and higher clock rates becomes. A damaged cell often puts the whole string out of order, so it needs to be replaced. This becomes more difficult with every further process step and is no longer possible after lamination.

Disclosure of the invention

With the invention, a solar cell module with the features of claim 1 is provided. Furthermore, a solar cell arrangement comprising a plurality of such solar cell modules is proposed.

The invention includes the idea of departing from the previous concept of the formation of solar cell arrangements from only electronically functional semiconductor components whose mechanical properties in no way meet the requirements of use. It also includes the idea of departing from the usual step sequence of a primary electrical interconnection of these semiconductor components and a secondary, so subsequent processing for mechanical stabilization and protection against environmental influences.

The invention therefore includes the idea of providing each individual solar cell with a housing which encapsulates the solar cell and is formed by potting, which has a wall permeable to sunlight at least over the front side of the solar cell. Furthermore, the invention includes the idea of providing a conductor arrangement enclosed in the housing together with the solar cell with electrical connection contacts placed in edge regions of the housing.

In an expedient embodiment, the housing is at least partially formed of a polymethyl methacrylate or polycarbonate or the like. From a current point of view, preference is given to a housing made entirely of plastic, which is designed in an economically easy-to-handle and cost-effective design, in particular as an injection-molded part, or composed of injection-molded parts.

In one embodiment, the housing comprises a rear, the edge regions of the solar cell at least partially encompassing and manufactured from highly stable plastic housing part and a front, made of highly transparent plastic housing part.

In a further embodiment, the housing has at least two edge regions mechanical connecting means for connecting adjacent solar cell modules with each other. Here, in particular, the mechanical connection means of the tongue and groove type or dovetail type or hook-eye type, and / or they have latching means. The concrete structural design of the mechanical connection means is usefully such that a single block without time-consuming and error-prone handling of the remaining components of an arrangement dissolved out of this and a replacement block or the repaired original block can be inserted just as inexpensively back into this.

In a further embodiment of the invention, the conductor arrangement comprises a prefabricated stamped grid or a conductor structure produced by laser structuring or laser-assisted coating.

In a further embodiment, at least some of the connection contacts are designed as plug contacts and / or with contact springs. This allows a particularly easy and quick installation and, if necessary, disassembly of the solar cell assembly or removal of a single module.

In a further embodiment of the invention, the housing has an antireflection coating and / or a hard coating on the front side of the solar cell for increasing the scratch resistance.

The proposed solar cell arrangement is characterized in that the solar cell modules are mechanically and electrically releasably connected to each other. In one embodiment, the arrangement has a frame surrounding the outer edge, composed of edge strips or also integrally manufactured frame. The shape of the solar cell modules can adapt to given freeforms, as thin wafers allow bending.

• – Die verkapselten Zellen lassen sich bei der weiteren Verarbeitung (Modulfertigung) leichter handhaben, die Verluste durch Bruch würden sich reduzieren.
• – Es gibt weniger Ausschuss bei der Modulfertigung, da beschädigte oder schlecht kontaktierte Zellen problemlos ausgetauscht werden können.
• – Bei Beschädigungen (Steinschlag, Vandalismus, Korrosion) kann die Gesamtanordnung durch Austausch der defekten Zellbausteine repariert werden.
• – Eine Umstellung des Modulformats betrifft nur noch den letzten Fertigungsschritt, keine weiteren Eingriffe in die Fertigungslinie sind nötig.
• – Die Zelle ist in der Kunststoffkapsel gegen Witterungseinflüsse geschützt. Glasplatte, Rückplatte und Laminierfolien sind nicht mehr erforderlich.
• – Es gibt eine deutliche Gewichtsersparnis; dadurch ergeben sich eine Reduzierung der Dachlast, erleichterte Installation und höhere Sicherheit.
• – Die Solarzellenbausteine sind von einer Zelle auf x Zellen (eine String- oder Modulgröße) skalierbar, d. h. die Modulgröße ist nur durch die Auslegung der eingegossenen Leiterstruktur zur Kontaktierung der Zellen begrenzt.
• – Es lassen sich zusätzliche Marktsegmente bei Erweiterung des Geschäftsmodells (Installateur- oder Heimwerkermarkt) erschließen.

In summary, the invention, at least in one or more of the above embodiments, offers the following advantages over the prior art:

• - The encapsulated cells are easier to handle during further processing (module production), the losses due to breakage would be reduced.
• - There is less rejection in module manufacturing, as damaged or badly contacted cells can be easily replaced.
• - In case of damage (stone chips, vandalism, corrosion), the entire arrangement can be repaired by replacing the defective cell components.
• - Changing the module format only affects the last production step, no further intervention in the production line is necessary.
• - The cell is protected in the plastic capsule against the weather. Glass plate, back plate and laminating films are no longer required.
• - There is a significant weight saving; This results in a reduction of the roof load, easier installation and increased safety.
• - The solar cell modules are scalable from one cell to x cells (one string or module size), ie the module size is limited only by the design of the cast-in conductor structure for contacting the cells.
• - Additional market segments can be developed by expanding the business model (plumbing or home improvement market).

drawings

Further advantages and advantageous embodiments of the subject invention are illustrated by the drawings and explained in the following description. It should be noted that the drawings have only descriptive character and are not intended to limit the invention in any way. Show it:

1 a schematic representation of a prepared in a known manner solar cell strings,

2A and 2 B Schematic diagrams (perspective view and cross-sectional representation) of a solar cell module according to the invention,

3 a detailed cross-sectional view of an embodiment of the solar cell module according to the invention,

4A and 4B a cross-sectional view and top view of another embodiment and

5 a sketch-like representation of an embodiment of the solar cell assembly according to the invention.

2A and 2 B show a solar cell module 20 in an injection molded housing 22 a solar cell 23 contains. The injection-molded housing 22 comprises a front, highly transparent potting layer or a front housing part 22a and a rear, largely the mechanical stability of the block securing potting or rear housing part 22b , In the case 22 are also interconnects 21 embedded with associated connection contacts.

The production of such a solar cell module is essentially as follows:
First, a first layer for forming a front housing part is injected into the mold with a plastic material that is completely transparent to sunlight. The solar cell with the front side (the busbars as printed conductors) is placed on this layer. The connection with the potted layer takes place either via adhesive action of this layer or by brief heating of the layer / solar cell composite.

To increase stability, the sides of the cell are overmolded with a stable, high-strength plastic. The lateral shape is carried out so that the cells can be firmly connected to each other, either by springs and grooves or similar to a puzzle. The required conductor tracks (including the connection contacts) can either be encapsulated as a punched grid or produced by laser and subsequent metallization (3D-MID). The conclusion is a sprayed layer of stable high-strength plastic. Expediently, the outer surface of the first (highly transparent) plastic layer, which forms the front side of the module in use, is provided with a hard layer (made of SiO _x or the like, for example, plasma-assisted in a vacuum).

3 shows a structure of this kind a little closer. The designation of the individual parts is based on 2A and 2 B and parts already explained above will not be described again here. With the numbers 31a . 31b are in 3 rear or front-side interconnects (busbars), and numeral 31c denotes the backside metallization of the solar cell 33 , The housing 32 includes here next to the front housing part 32a and the rear housing part 32b mechanically high-strength side parts or building block frame parts 32c , The front housing part 32b carries a hard material coating 32d ,

4A and 4B show in a similar representation and figuring like the 2A . 2 B and 3 another solar cell module 40 , which serves as a mechanical connecting means between adjacent components groove areas 44a and feathered areas 44b having. Here, in each case at two mutually perpendicular side edges of the housing 42 Groove areas and provided on the two remaining side edges spring portions, as well in 4B can be seen.

In the groove on the longitudinal side of the block are first contacting elements 46a provided for making a connection with the respective adjacent module, and on the opposite spring are second contact elements 46b provided in a corresponding position and design, which when mounted in electrically conductive engagement with the first contact elements 46a of the neighboring building block. The interconnects necessary for the connection of the solar cells are to be integrated into the encapsulation so that plug-like contacts are present on the outer contour (such as, for example, when casting printed conductors in printed circuits or inserting punched grids before encapsulation) or to electrically connect with a peripheral element.

5B shows a sketch in plan view of a solar cell array 50 as an array of 6 × 10 solar cell modules 20 of the kind described above, surrounded by a frame 51 , which in the embodiment shown consists of individual skirting 51a and corner connectors 51b is composed. The sidebars 51a include busbars (not shown) that are merged at a central point. A sidebar is provided with the connection element for the wiring of the module; this connection is cast in with. The edge strips and corner connectors are, like the housing of the solar cell modules, manufactured as injection-molded parts. Special corner connectors can be dispensed with if instead angular edge strips are provided, which represent an integrated version of two straight edge strips and a corner connector.

With a suitable adaptation of the edge strips to the edge regions of the solar cell modules, it is possible to connect the edge strips in the same way with the solar cell modules, as these are interconnected, for example, with the in the 4A and 4B shown and explained above groove and tongue connection. This allows a very simple frame assembly.

From the aspect of the electrical connection or the connection of a solar cell arrangement, it is possible to integrate a frame with a connection box and / or a cross-connection. The finished product can consist of individual panels, which are then brought into the desired modular form by the end customer, or a module is produced therefrom which corresponds to the desired specification.

The embodiment of the invention is not limited to the examples and highlighted aspects described above, but also possible in a variety of modifications.

Claims (11)

Solar cell module ( 20 ; 30 ; 40 ) for forming a solar cell array ( 50 ) from a plurality of solar cells ( 23 ; 33 ; 43 ), comprising - a solar cell, - a housing encapsulating the solar cell, formed by potting ( 22 ; 32 ; 42 ), which at least over the front of the solar cell, a sunlight-permeable wall ( 22a ; 32a . 42a ), and - a conductor arrangement cast into the housing together with the solar cell ( 21 ; 31a ; 31b ) with placed in edge regions of the housing electrical connection contacts ( 46a ; 46b ). A solar cell package according to claim 1, wherein said housing is at least partially formed of a polymethyl methacrylate or polycarbonate or the like. Solar cell module according to claim 1 or 2, wherein the housing has a rear, the edge regions of the solar cell encompassing and made of highly stable plastic housing part ( 22b ; 32b ; 42b ) and a front, made of highly transparent plastic housing part ( 22a ; 32a ; 42a ). Solar cell module according to one of the preceding claims, wherein the housing at at least two edge regions mechanical connecting means ( 44a ; 44b ) for connecting adjacent solar cell modules with each other. Solar cell module according to claim 4, wherein the mechanical connection means of the tongue and groove type ( 44a ; 44b ) or dovetail type or hook-eye type and / or latching means. Solar cell module according to one of the preceding claims, wherein the conductor arrangement ( 21 ; 31a ; 31b ) comprises a prefabricated stamped grid or a ladder structure produced by laser structuring or laser-assisted coating. Solar cell module according to one of the preceding claims, wherein at least a part of the connection contacts ( 46a ; 46b ) is designed as plug contacts or spring contacts. Solar cell module according to one of the preceding claims, wherein the housing ( 22 ; 32 ; 42 ) at the front of the solar cell an anti-reflective coating and / or a hard coating ( 32d ) to increase the scratch resistance. Solar cell arrangement ( 50 ) of a plurality of solar cell modules according to one of the preceding claims, wherein the solar cell modules ( 20 ) are mechanically and electrically releasably connected to each other. Solar cell arrangement according to claim 9, with a peripheral edge surrounding the outer edge ( 51a ) composite framework ( 51 ). Solar cell arrangement according to claim 9, with a surrounding the outer edge, made of one piece frame.

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