DE102013203636A1 - Semi-transparent thin film solar module for e.g. facade construction, has light transmissive portions, which are formed on substrate with respect to contact pattern of cell regions - Google Patents

Abstract

The invention relates to a semitransparent thin-film solar module (10) comprising a multiplicity of cell regions (11) electrically connected to one another via a contact pattern, which are arranged on a common transparent substrate, wherein light-transmissive regions (10a) are independent of the contact pattern (11a) of the cell regions on the substrate are formed. It further relates to a corresponding method for producing a semitransparent thin-film solar module.

Description

The invention relates to a semitransparent thin-film solar module comprising a multiplicity of cell regions which are electrically connected to one another via a contact pattern and which are arranged on a common transparent substrate. It further relates to a method for producing such a thin-film solar module.

State of the art

With the rapidly advancing distribution of photovoltaic systems has been working for years on the link with architectural or other design solutions (such as in vehicle), where a certain transparency is required or at least advantageous. Semitransparent photovoltaic modules are especially in facade construction, but z. B. also used in vehicle roofs. Thin-film solar modules are a serious alternative to traditional crystalline modules, which are particularly prized for their energy conversion efficiency, especially for large area applications due to their low cost price.

The basis for semitransparent thin-film solar modules is a support (substrate, usually made of glass, but also foil) on which the functional layers are deposited. Different technologies and deposition methods can be used, such as sputtering or vapor deposition.

The basic structure is how 1 schematically shows a carrier 1 , a transparent but conductive front contact 3 , which is translucent and electron-conducting, a power-generating absorber 5 and a conductive back contact 7 , The front contact can consist of several individual layers. The absorber can consist of several individual layers. Furthermore, several PIN or NIP and PN or NP transitions may be included in the absorber. The back contact can consist of several individual layers.

Between the depositions of the different layers, a laser structuring step takes place, each of which has a trench 3a in front contact, 5a in the absorber or 7a in absorber and back contact results. These trenches 3a . 5a respectively. 7a are required to ensure the electrical connection of the individual cells in the module.

Subsequently, the semitransparent laser structuring is carried out by removing a part of the layer structure again from the carrier glass in order to generate a partial light transmission (examples: see 2A to 2C ). Then an encapsulation takes place to protect the layers from the weather.

You can distinguish the layer structures to the effect whether the back contact is translucent or not translucent. In the metallic back contact, the light not converted in the absorber is reflected back into the absorber in order to increase the efficiency. If one uses a translucent back contact (eg doped ZnO), an additional planar reflector material is applied, for. As white color, white encapsulation film, etc., to achieve this increase in efficiency.

The translucent back contact has advantages in terms of structuring capability (susceptibility to tinsel formation is reduced) compared to the metallic back contact, in the area stability (oxides do not show the typical start-up behavior such as metals in fingerprints, etc.) and in the field of costs. Because of the required reflection in the infrared wavelength range, silver must be used as the material in metallic back contact. For applications with semitransparency, metallic back contacts have hitherto mostly been used, since the applied additional flat reflectors would cancel the established semitransparency. The above-mentioned advantages of the translucent back contact with additional reflector could therefore previously not be used for semi-transparency applications or only in the absence of the flat reflector and thus waiver of electrical power.

From the DE 10 2009 059 208 is a method for the production of semitransparent photovoltaic modules is known in which previously applied over the entire surface layers (such as a back electrode layer and back reflector layer or a color-active layer) are then partially removed by laser structuring to create the desired semi-transparent surface.

Disclosure of the invention

The invention provides a semitransparent thin-film solar module with the features of claim 1. Furthermore, a method for producing such a thin-film solar module with the features of claim 7 is provided. Advantageous further developments of the inventive concept are the subject of the respective dependent claims.

From device aspects, the invention includes the idea that light transmissive areas are independent of the contact pattern of the cell areas on the substrate, the geometrically by a plurality of mutually parallel separation or isolation trenches, are formed. It should therefore be consciously departed from exploiting functionally essential isolation trenches of the thin-film solar module at the same time for generating the desired semitransparency. Instead, the desired semitransparency should be generated by additional (electrically nonfunctional) trench regions in the layer structure of the module. From a procedural point of view, the invention includes the idea that the entire functional structure of the cell regions, optionally with the exception of the front contact, is removed in regions which are predetermined as translucent by local laser ablation.

This proposed detachment of the spatial arrangement of the translucent areas of the contact pattern structure of the cell areas represents a departure from the previous view of the expert and is advantageous insofar as they have a much greater flexibility in the specific optical design of the desired semitransparency one hand, and independence from the process flow the generation of the cell structure (including the contact structure) offers.

In a first embodiment, the entire functional structure of the cell areas is removed in the light-permeable (trench) areas. Alternatively, there is the option that in the translucent (trench) areas of the functional structure of the cell areas, with the exception of the front contact, is removed.

In a design that meets the most practical requirements and that is technologically easy to implement at the same time, the cell areas and the light-transmissive areas are strip-shaped in each case, and the orientation of the light-permeable strips is inclined for orientation of the cell area strips. More specifically, the orientation of the translucent stripes is at right angles to the orientation of the cell area stripes. When using a coordinate-controlled processing station, however, the proposed method, laser ablation, can also be used to realize differently shaped (practically arbitrarily) transparent regions in the module structure and, in particular, also fulfill aesthetic or artistic requirements for an overall appearance of the module or a photovoltaic system composed of several modules ,

In a further embodiment, the thin-film solar module is equipped with a back reflector outside the transparent areas. If a colored appearance is desired, a color layer or a selectively acting back reflector may also be provided.

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 cross-sectional view of the structure of a conventional thin-film solar module,

2A to 2C Top views of embodiments of semitransparent thin film solar modules,

3 a schematic plan view of an embodiment of the thin-film solar module according to the invention,

4A and 4B schematic cross-sectional representations of an embodiment of the thin-film solar module according to the invention,

5A and 5B schematic cross-sectional views of an embodiment of the thin-film solar module according to the invention and

6A and 6B schematic cross-sectional views of an embodiment of the thin-film solar module according to the invention.

Embodiments of the invention

3 shows in a schematic plan view of a thin-film solar module 10 (or a section of such), which consists of a strip arrangement of cell areas 11 exists according to 1 are constructed and in their transition areas each have a group of structuring trenches 11a is provided. Each group of structuring trenches here include trenches (also referred to as "Patterns 1 to 3"), as they are in 1 with the numbers 3a . 5a and 7a are designated. Right-angled to this stripe structure of the cell areas are light-transmissive areas 10a in which (as described in more detail below) at least a part of the solar cell functional structure is removed by laser ablation and which are thereby transparent or partially transparent.

Since the semitransparent layout is independent of the layout of the cell structuring, the degree of transparency can be chosen as desired. Depending on the degree of transparency, it is possible to freely select the distances and widths for opaque and transparent areas, without changing the cell layout of the solar module or to influence the module voltage. A further advantage of this type of semitransparent structuring of a solar module structure is the possibility of completely removing the entire layer structure, including front contact, back reflector and possibly further functional layers, in the transparent regions by a laser process step.

In the opaque area, one can assume that all applied layers are> 95% opaque on top of each other.

4A and 4B show in schematic cross-sectional representations two variants of the realization of (partially) translucent areas in a thin-film solar module, which in 4A with numeral 40 and in 4B with numeral 40 ' is designated. The cell structure is the same in both variants and comprises a carrier glass 41 , a front contact 43 , an absorber layer 45 and a back contact 47 and a back reflector 49 , By means of a symbolically represented laser beam L is in this functional layer structure in each case by ablation of either all functional layers (in the solar module 40 according to 4A ) or preserving the front contact layer 43 (at the solar module 40 ' according to 4B ) a ditch 40a respectively. 40a ' generated. In this trench, the solar module is in the execution after 4A transparent or in the execution after 4B milky transparent. There is no functional difference between the two variants, so the choice of one of the variants can be made under aesthetic and, if necessary, technological aspects.

The embodiments according to 5A and 5B correspond to those according to the structure or method according to the invention 4A and 4B However, for the above-described construction of the solar module is in each case a cover layer 59a on the back reflector 59 added. This is also in the laser ditch 50a respectively. 50a ' away.

6A and 6B also show a similar solar cell construction as 4A and 4B However, here is instead of a back reflector only a cover layer 69a intended. Again, the cover layer by laser ablation in the trench 60a respectively. 60a ' away. The lack of a back reflector makes this structure more cost-effective, and by suitable choice of the cover layer, certain color and other aesthetic effects can be realized or optimized.

Within the scope of expert action, further refinements and embodiments of the method and apparatus described here by way of example only arise.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102009059208 [0009]

Claims (8)

Semitransparent thin-film solar module ( 10 ; 40 ; 40 '; 50 ; 50 '; 60 ; 60 ' ) of a plurality of electrically via a contact pattern, which isolation trenches ( 7a ) in a back contact layer ( 5 ), interconnected cell areas ( 11 ), each comprising a functional structure of several sub-layers and on a common transparent substrate ( 1 ; 41 ; 51 ; 61 ) are arranged, characterized in that light transmissive areas ( 10a ; 40a ; 40a '; 50a ; 50a '; 60a ; 60a ' ) of the thin-film solar module as the contact pattern ( 11a ) of the cell regions geometrically independently arranged trench regions are formed at least in partial layers of the functional structure of the cell regions. Thin-film solar module according to claim 1, wherein in the light-transmissive regions ( 10a ; 40a ; 40a '; 50a ; 50a '; 60a ; 60a ' ) the entire functional structure of the cell areas ( 11 ) is removed. Thin-film solar module according to claim 1, wherein in the light-transmissive regions ( 10a ; 40a ; 40a '; 50a ; 50a '; 60a ; 60a ' ) the functional structure of the cell areas ( 11 ), with the exception of the front contact ( 3 ; 43 ; 53 ; 63 ), is removed. Thin-film solar module according to one of the preceding claims, wherein the cell areas ( 4 ), including isolation trenches ( 7a ) on the one hand and the translucent trench areas ( 10a ; 40a ; 40a '; 50a ; 50a '; 60a ; 60a ' On the other hand, each strip-shaped and the orientation of the light-permeable trench regions is inclined to the orientation of the cell region strips. Thin-film solar module according to claim 4, wherein the orientation of the light-permeable trench regions ( 10a ; 40a ; 40a '; 50a ; 50a '; 60a ; 60a ' ) at right angles to the orientation of the cell area strips ( 11 ). Thin-film solar module according to one of the preceding claims, having a back reflector ( 49 ; 59 ) outside the translucent areas. Method for producing a semitransparent thin-film solar module ( 10 ; 40 ; 40 '; 50 ; 50 '; 60 ; 60 ' ) of a multiplicity of cell regions which are electrically connected to one another via a contact pattern and which are arranged on a common transparent substrate ( 1 ; 41 ; 51 ; 61 ), wherein the entire functional structure of the cell areas, optionally with the exception of the front contact, in in as trench regions predetermined ( 10a ; 40a ; 40a '; 50a ; 50a '; 60a ; 60a ' ) is removed by local laser ablation. Method according to claim 7, wherein for generating strip-shaped light-transmitting trench regions ( 10a ; 40a ; 40a '; 50a ; 50a '; 60a ; 60a ' ) a laser beam (L) with predetermined stripe spacings linearly over the prefabricated functional structure of the cell areas ( 11 ) to be led.

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