DE102007018711A1 - solar cell module - Google Patents

Abstract

In order to produce solar cell modules with which a more cost-effective production of solar panels is possible, it is proposed that the solar cell module comprises a plurality of solar cells and a common frame for this, wherein the frame comprises a lower and an upper frame part with webs, wherein the solar cells of the module substantially in a plane are arranged and spaced from each other between the upper and lower frame parts, wherein the webs are arranged in the mounted state of the module between adjacent solar cells and wherein the frame parts made of a thermoplastic, fully fluorinated plastic material and are materially connected to each other such that the solar cells the module at all edges of the frame parts and their webs are completely and liquid-tight surrounded.

Description

The The invention relates to a solar cell module and solar cell panels, which integrates several solar cell modules and interconnects them contain.

conventional individual cells become solar cell modules with individual frames made of an elastomeric material, such as FPM or EPDM, mounted and the framed single framed solar cells then become one Solar cell panel integrated. The frames made of elastomeric material are usually constructed of two frame parts, these with each other be connected in a press fit and the single solar cell between hold each other. The frames cover the edges sealing the solar cells and protect them and the Contact points for electrical connections before acting fluids that are in operation of the panels flow around the modules with the cells.

alternative solar cells have been completely embedded in EVA films, wherein the EVA material also includes the solar cell surfaces, the edges as well as the electrical contact points completely covered.

The Solar panels are usually for outdoor use created and are thus the sunlight and other weather conditions, especially extreme temperature fluctuations, exposed.

The Lifetimes of the solar cell panels are currently at 20 years and more stated in which the protective effect for the Solar cells must be preserved.

The Frames or foils must be the solar cells not only permanently against moisture or fluid access Protect, but they must also be sized be that with very strongly fluctuating temperatures the occurring different thermal expansions of the solar cell on the one hand and the frame material, on the other hand becomes.

there should cover the edges of the solar cells as possible be low to an optimal surface area of the solar cells directly exposed to sunlight and thus for the photovoltaic to be able to use.

The Solar cells are provided with electrical connections, which led out of each single frame and then be interconnected in the solar cell panel.

at this type of conventional production of solar panels a relatively high amount of work is necessary, which is based on the Costs in the production of solar panels significantly affects.

task It is the solar cell modules to propose with which a more cost-effective production of solar panels becomes possible.

These The object is achieved by a solar cell module solved as defined in claim 1.

The Reduce solar cell modules according to the invention the assembly effort in the manufacture of the panels considerably, since by integrating a plurality of solar cells into a module the number of components to be handled is significantly reduced.

The Integration of multiple solar cells in a module also leaves a reduction of the wiring effort during production the panels to, by the solar cells of a module internally, d. H. within the module, can be interconnected and that Module even then only two electrical connections needed. Correspondingly lower falls also the Number of cable glands in the frame parts of what also beneficial for the safe shielding of the Edges of solar cells to the environment effect.

Preferably become five or more solar cells in an inventive Module integrated.

For the integration of multiple solar cells within an inventive Module offers in particular a one-line arrangement of the solar cells at.

Furthermore, the material connection of the frame parts provides a much greater security for the sealing of the solar cell edges and their durability than the pressing of the elastomeric material frames allowed.

Different as with the cells laminated with foils, the surface remains the solar cells uncovered, so that one of the aging effects of Modules aimed at reducing the transparency of laminating films was completely eliminated.

The Production of frame parts meeting the above-mentioned claims is enough, is with the usual elastomer materials not possible. The invention for Use of fully fluorinated thermoplastic materials also have a lower tendency to embrittlement and in particular with a significantly better temperature, Weather and chemical resistance.

by virtue of their thermoplastic properties can be the plastic materials used in the invention even with a complex shape process.

So can be in the frame parts very easy form of adjustment, the exact positioning of the solar cells within the module allow. The adjusting means are preferably at least one provided the frame parts and include, for example, projections and / or returns.

at a particularly preferred embodiment, both Frame parts following the edge of each solar cell recesses on. This can be achieved that the two frame parts by the solar cells positioned in between are aligned become. In addition, here is the opportunity form the two frame parts identical, so that with a single tool both frame parts can be manufactured.

Advantageous are in the plastic materials to be used according to the invention also the excellent dielectric properties, in particular the relative dielectric constant and the damping coefficient.

Preferably are the solar cells of a module within the frame electrically interconnected, d. H. the electrical contact points of the individual solar cells and the electrical connection lines are covered and protected by the frame parts. Here offers in particular the serial electrical interconnection of Cells on. The module itself with its majority of solar cells needed only two, the frame material penetrating connections the in the production of the panels with the connections additional modules must be interconnected.

Thermoplastic, fully fluorinated plastics in the context of the present invention are to be understood to mean plastics which are thermoplastically processable in the conventional sense, ie form a melt which has a viscosity which permits standard melt processing techniques. Such plastics have a non-zero melt index ( ASTM D1238-88 ) on.

These include co-polymers of tetrafluoroethylene (TFE) with different co-monomers and co-monomer contents, the z. B. as FEP, MFA, PFA or Teflon ^® AF are known.

A newer type of TFE co-polymer is disclosed in the disclosures WO 00/08071 . WO 01/60911 and WO 03/078481 described and available on the market under the brand Moldflon ^® with co-monomer contents <3 mol%. More preferably, the proportion of the co-monomer is less than 1 mol%.

preferred Co-monomers are selected from hexafluoropropylene, perfluoro (alkyl vinyl ether), Perfluoro- (2,2-dimethyl-1,3-dioxoles) and chlorotrifluoroethylene.

The Moldflon ^® materials, in comparison with PTFE, PFA and FEP, a over a very wide temperature range, ie in particular from 0 ° C to 300 ° C, the highest storage modulus E ', as measured by dynamic mechanical thermal analysis DMTA.

Further, the mechanical properties of the Moldflon ^® -Materials remain to get close to the melting point.

The Water absorption is very low, so that the frame parts as Precision components can be realized, which are also in contact remain dimensionally stable with aqueous liquids.

The Table 1 below gives an overview of the important properties of various examples of according to the invention to using polymers. It also contains for comparison the corresponding data for conventional PTFE.

As an alternative to co-polymers of TFE, polymer blends with PTFE as a major component and other thermoplastic polymers can be used. Examples can be found in the WO 00/08071 , Other examples are those in the EP 1 077 230 A1 described materials. Table 1 Physical properties of fully fluorinated plastics property unit PTFE (Comp.) Mod. PTFE Moldflon ^® PFA MFA FEP Generally Continuous operating temperature ° C 260 260 260 250 250 205 Specific density g / m ³ 2.13-2.20 2.13 to 2.19 2.14 to 2.18 2.12 to 2.17 2.12 to 2.17 2.12 to 2.17 flammability UL fire class V-0 V-0 V-0 V-0 V-0 V-0 oxygen Index % > 95 > 95 > 95 > 95 > 95 > 95 water absorption % <0.01 <0.01 <0.01 <0.03 <0.03 <0.01 thermal melting point ° C 327 327 315-324 300-310 280-290 253-282 thermal conductivity W / K × m 0.22 to 0.23 0.22 to 0.23 0.22 to 0.23 0.22 0.22 0.2 coefficient of thermal expansion 1 / K × 10 ^-5 12-17 12-17 12-16 10-16 12-20 8-14 Specific heat at 23 ° C KJ / kg × m 1.01 1.01 1.03 1.09 1.09 1.17 Mechanically Tear resistance at 23 ° C MPa 29-39 29-39 23-32 27-32 22-36 19-25 elongation at break % 200-500 300-600 150-450 300 300-360 250-350 Tensile modulus at 23 ° C MPa 400-800 650 400-630 650 440-550 350-700 Shore hardness D 55-72 59 55-65 60-65 59 55-60 Friction coefficient dyn. Dry steel 0.05-0.2 0.05-0.2 0.05-0.2 0.2-0.3 0.2-0.3 0.2-0.35 electrical Specific volume resistance Ohm × cm 10 ¹⁸ 10 ¹⁸ 10 ¹⁸ 10 ¹⁸ 10 ¹⁸ 10 ¹⁸ Dielectric constant at 10 ⁶ Hz 2.0-2.1 2.0-2.1 2.0-2.1 2.1 2.0 2.1 Dielectric loss factor at 10 ⁶ Hz X10 ^-4 0.7 0.7 0.7-1.1 <5 <9 surface resistivity ohm 10 ¹⁷ 10 ¹⁷ 10 ¹⁷ 10 ¹⁷ 10 ¹⁷ 10 ¹⁶ Dielectric strength KV / mm 40-100 50-110 50-100 50-80 34-38 50-80

The cohesive connection, for example, by gluing respectively. But sometimes this does not lead to the desired Safety, especially with regard to the long service life of the Solar cell modules.

Cheaper in this regard, the welding of the frame parts. However, this is a challenge especially in the case of the preferred fully fluorinated plastic materials to be used according to the invention tion because these materials have melting points that are far beyond the maximum ambient temperatures allowed for the solar cells.

Especially Therefore, preferred solar modules have one or more in the frame integrated resistance heating elements. Here you can with a short current pulse a sufficient amount of energy for a reliable sealing weld in the too enter welding areas of the frame parts, without that a temperature increase affecting the solar cells at the edges of the solar cells encompassed by the frame parts is produced. This is realizable even if the frame parts with very small tolerance regarding the dimensions of the Solar modules are manufactured and therefore the edges of the solar cells in the Essentially lie directly against the plastic material of the frame parts.

The Resistance heating elements may be in the solar cell module remain permanently.

The Resistance heating element can be used as wire frame part or sheet metal frame part are formed, which substantially the contours of a frame part along with its jetties follows. Such a heating element is used in production of the module simply inserted between the two frame parts and then welded into the module or its frame as a lost part.

alternative the resistance heating element may be multi-part, wherein the heating element then have recesses in the places where electrical Lines transversely to the frame parts and their webs run around a physical and electrical contact of the heating element with these wires as well as a direct energy input into them To avoid module parts safely.

The The invention further relates to a process for the preparation of Solar cell modules according to the invention.

• – ein oberes und ein unteres Rahmenteil, aus einem vollfluoriertem Kunststoffmaterial gefertigt, werden bereitgestellt, welche mit Aufnahmen für mehrere Solarzellen versehen sind;
• – Positionieren der Solarzellen in den Aufnahmen eines Rahmenteils;
• – Verschalten der Solarzellen;
• – Positionieren des zweiten Rahmenteils auf dem einen, die Solarzellen aufnehmenden Rahmenteil; und
• – stoffschlüssiges Verbinden der beiden Rahmenteile am im Wesentlichen gesamten Rand jeder Solarzelle des Moduls.

The method according to the invention is characterized by the steps:

• An upper and a lower frame part made of a fully fluorinated plastic material are provided, which are provided with receptacles for a plurality of solar cells;
• - Positioning of the solar cells in the receptacles of a frame part;
• - interconnecting the solar cells;
• - Positioning of the second frame part on the one, the solar cell receiving frame part; and
• - Bonded connection of the two frame parts at substantially the entire edge of each solar cell of the module.

The Frame parts for use in the invention Methods can be produced in a variety of methods in the case of simple contours of the frame parts this can be punched out of a sheet material.

at more complicated geometries can either be made of sheet materials stamped frame parts are machined or machined A machining process is used for the entire production used the frame parts.

A particularly preferred method of preparation is in the injection molding process before, because here also geometries with complex structure in one production step are available.

The Solar cells to be processed in the process can either individually contacted and provided with separate connection cables The majority of solar cells that are or are preferred be used within a module interconnected and electrically connected within the module.

A cohesive connection of the frame parts, for example be achieved by gluing, as already mentioned above.

Prefers in terms of greater security that is Weld the frame parts, as above also in detail.

According to a preferred method, the welding of the frame parts can take place by means of resistance heating elements which are or can remain in the frame as an integral part. The resistance heating elements are configured to substantially overlap each other however, preferably have recesses at the locations where electrical connections between the individual solar cells are made or connection cables from the solar cells pass through the frame to the outside.

Prefers The resistance heating elements comprise a sheet metal frame part, which in the Essentially reproduces the welds to be generated and which in positioning the second frame part between the two frame parts is inserted. For the production of the welded connection then the sheet metal component must be contacted only electrically, which preferably with already provided in the context of electrical connections is accomplished.

alternative It is conceivable that the resistance heating elements in one or both Frame parts, for example in the form of resistance wires, to be incorporated, in particular as inserts during injection molding in pour these.

These and further advantages of the invention are described below with reference to the Drawings explained in more detail.

It show in detail:

1 : A perspective view of an assembled solar cell module according to the invention;

2 : Exploded view of the module of 1 ;

3 : A plan view of a frame part of the module of 1 ;

4 a sectional view through a solar cell module according to the invention along line 4-4 in FIG 1 before welding the frame parts; and

5 : the sectional view of the 4 after welding the frame parts of the module of 1 ,

1 shows a perspective view of a solar cell module according to the invention 10 with a frame 12 , which consists of two frame parts, an upper frame part 14 and a lower frame part 16 , is composed. In window-like openings 20 of the frame 12 are solar cells 18 arranged. The openings 20 are over jetties 22 separated from each other.

The solar cells 18 are over the two connectors 24 electrically connected to the environment and otherwise completely at its edge regions of the material of the frame parts 14 and 16 as well as their webs 22 surrounded and protected.

At the respective terminal front edges of the frame 12 occur Heizleiteranschlüsse 26 out. Their function is described below with reference to the drawings 2 to 5 explained in more detail.

2 shows the solar cell module 10 in an exploded view. The items of the module 10 are arranged here as it is the production process for the production of the complete module 10 corresponds approximately.

On the lower frame part 16 is a heating element 28 applied, which essentially the contours of the frame part 16 with his the windows 20 dividing webs 22 follows. The width of the individual parts of the heating element 28 are compared with the width of the parts of the lower frame part 16 and its webs 22 kept a little narrower, so that both sides of the individual parts of the Heizleiterelements 28 the material of the lower frame part 16 remains uncovered. The frame part is preferred 16 at its top with a recessed surface area 30 provided (see. 3 ), in which the Heizleiterelement 28 can be inserted.

The outer parts of the lower frame part 16 as well as the footbridges 22 that the windows 20 delimit against each other, include groove-like depressions 34 respectively. 32 , which receive electrical lines that serve to connect the solar cell modules, ie in particular the connecting cables 24 as well as the electrical lines 36 that the solar cells 18 connect with each other. For the heat conductor connections to be fitted on the front side 26 is at the frontal areas of the frame parts 16 also one groove each 38 provided see who the Heizleiteranschlüsse 26 take up.

The heating element 28 can be formed in several parts (not shown) and then points in the region of the grooves 32 and 34 Open on, so that a sufficient distance between the Heizleiterelement 28 and the electrical wires 24 respectively. 36 is ensured. This also avoids a thermal bridge between the heating element 28 and the electrical wires 24 respectively. 36 as well as the directly connected solar cells 18 , For multi-part heating elements then several pairs of connecting lines 26 needed.

This can be of particular importance since the welding of the two frame parts 14 and 16 Temperatures of up to 300 ° C or more depending on the plastic material, temperatures that must be avoided for the solar cells in the short term absolutely.

The frame parts 14 and 16 show at their window-like openings 20 round running tabs 40 on, with the frame parts 16 respectively. 14 and their webs 22 one receptacle each for a solar cell 18 form and position this exactly predetermined position in the module.

Preferably, the depth of the projections 40 formed photographs for the solar cells so that they are about half the thickness of the solar cells 18 can absorb, so that on the in the lower frame part 16 positioned solar cells 18 still aufzulegende upper frame part 14 through the outer contours of the solar cells 18 is positioned in an exact manner.

Once the frame part 14 on top of that the solar cells 18 already containing solar cells 18 is applied, results in a configuration of the frame and the heat conductor element received between them 28 as in the sectional view of 4 is shown. After that are the frame parts 14 and 16 with their outer edges 41 directly on each other and keep between them in the recesses 30 the heating element 28 , The frame parts 14 and 16 touch each other with their faces facing each other on the windows 20 pointing areas and form there in the in 4 state still shown a cavity 42 out. In the last manufacturing step, a short current surge through the Heizleiterelement 28 applied, heats the Heizleiterelement 28 to a temperature above the melting point of the plastic material of the frame parts 14 and 16 and leads to a fusion of the frame parts 14 and 16 both on their outer, directly adjacent areas 46 as well as in the field 44 where previously the cavity 42 was present (cf. 5 ).

So that all side edges of the heating element 28 from the plastic material of the frame parts 14 and 16 cohesively connected to each other and close this from the environment. At the same time, the side edges of the solar cells 18 continuously from the two frame parts 14 and 16 as well as their webs 22 surrounded and protected. The in the assembled state of a panel surrounding the solar cell modules partially corrosive liquids ha ben now only in contact with the surfaces of the solar cell within of the windows 20 defined areas and can no longer to the side edges of the solar cells 18 reach.

Due to the inventive selection of plastic materials for the production of the frame parts 14 and 16 , namely, fully fluorinated thermoplastics, not only ensures that a close concern of these frame parts 14 and 16 at the edges of the solar cells 18 takes place and this sealing closes, but the selection of materials also ensures that this tightness during the life of the solar cell, ie for 20 years or more, is maintained. This is particularly true for the plastics from Moldflon ^® type.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• WO 00/08071 [0026, 0032]
• WO 01/60911 [0026]
• WO 03/078481 [0026]
• - EP 1077230 A1 [0032]

Cited non-patent literature

• ASTM D1238-88 [0024]

Claims (23)

Solar cell module comprising a plurality of solar cells and a common framework for this, the framework a lower and an upper frame part with webs, wherein the solar cells of the module arranged substantially in one plane and spaced apart between the upper and lower frame members are arranged, wherein the webs in the assembled state of the module are arranged between adjacent solar cells, and wherein the Frame parts made of a thermoplastic, fully fluorinated plastic material made and connected to each other materially connected are that the solar cells of the module on all edges of the frame parts and their webs completely and liquid-tight are surrounded. Solar cell module according to claim 1, characterized in that at least one of the frame parts comprises adjusting means, with Help those of the solar cells adjustably used in the frame are. Module according to claim 2, characterized in that the adjusting means projections and / or recesses include. Module according to one of claims 1 to 3, characterized in that the solar cells arranged in a row are. Module according to claim 4, characterized in that the solar cells are electrically connected in series. Module according to one of claims 1 to 5, characterized in that a first solar cell with a first provided by the frame passing outward connection is that and another, last solar cell with another provided by the frame passing outward connection is, wherein the solar cells except the first and last So larzelle within the frame of the module without stepping outside Connections are electrically connected to each other. Module according to one of the preceding claims, characterized in that the thermoplastic, fully fluorinated Plastic material is a thermoplastically processable PTFE material is. Module according to claim 7, characterized in that the thermoplastic PTFE material is a TFE copolymer, wherein the comonomer content is preferably 3.5 mol% or less, in particular less than 3 mol%, more preferably less than 1 Mol%. Module according to claim 8, characterized in that the co-monomer is selected from hexafluoropropylene, perfluoro (alkyl vinyl ether), Perfluoro (2,2-dimethyl-1,3-dioxoles) and chlorotrifluoromethylene. Module according to one of claims 1 to 7, characterized in that the PTFE material is a polymer blend is, comprising PTFE and a thermoplastically processable plastic. Module according to one of the preceding claims, characterized in that the frame parts produced by injection molding Components are. Module according to one of the preceding claims, characterized in that the frame in the cohesive contains areas to be connected resistance heating integrated. Process for producing a module according to one of claims 1 to 12, characterized in that - one Upper and a lower frame part, made of a fully fluorinated plastic material manufactured, which are provided with recordings for several solar cells are provided; - Positioning the solar cells in the receptacles of a frame part; - interconnect the solar cells; - Positioning of the second frame part on the one, the solar cells receiving frame part; and - cohesive Connecting the two frame parts at substantially the entire edge every solar cell of the module. Method according to claim 13, characterized in that that when providing the frame parts of these from a sheet material be punched out. Method according to claim 13 or 14, characterized that the frame parts by means of a machining process to be obtained. Method according to claim 13, characterized in that that the frame parts are produced by injection molding. Method according to one of claims 13 to 16, characterized in that the interconnection of the solar cells contacting them with separate connection cables per solar cell includes. Method according to one of claims 13 to 16, characterized in that the interconnection of the solar cells electrically connecting the solar cells within the module includes. Method according to one of claims 13 to 18, characterized in that the material-locking connection the frame parts comprises a welding of the frame parts. Method according to claim 19, characterized that welding by means of resistance heating elements he follows. Method according to claim 19, characterized that the resistance heating elements when positioning the second Frame part between the two frame parts are inserted. Method according to claim 20, characterized in that that the resistance heating elements in one or both frame parts are incorporated. Solar cell panel comprising a housing and a plurality of the solar cell modules according to one of claims 1 to 12.