CA2360814A1

CA2360814A1 - Solar module

Info

Publication number: CA2360814A1
Application number: CA002360814A
Authority: CA
Inventors: Martin Kurth
Original assignee: Individual
Current assignee: Kurth Glas and Spiegel AG
Priority date: 1999-02-01
Filing date: 2000-02-01
Publication date: 2000-08-10
Also published as: HUP0104864A3; CZ20012282A3; CN1327618A; JP2002536834A; CN1189949C; DE50002347D1; AU756285B2; PL197540B1; AU2090200A; EP1153440A1; HUP0104864A2; WO2000046860A1; ATE241857T1; PL349073A1; ZA200104858B; TR200102207T2; EP1153440B1; KR20010108137A; BR0007893A

Abstract

The invention relates to a solar module (1) with two opposite glass substrates (2, 3) which are interlinked at their edges by way of a sealing spacer frame (4). In the air-filled space (11) between said substrates a plurality of solar cells (7) is arranged at a distance from the glass substrates (2, 3). Said solar cells (7) are electrically connected via conducting lines (6) which are mounted on the glass substrates. Said conducting lines (6) are further mounted exclusively on a single glass substrate (2, 3) via flexible spacer elements.

Description

Solar Module The present invention relates to a solar module according to the introductory part of the claim 1.
A solar module is known e.g. from EP-A-0 525 225 which is based on a glass sub-strate consisting of hardened solar glass of 4 mm thickness. Onto the glass sub-strate a stack of layers is laminated consisting of a first synthetic film, electrically interconnected solar cells, a second synthetic film and a composite film as a cover film. Laminating is effected under vacuum at an elevated temperature in which process the synthetic films are welded onto each other and forming a solid com-pound with the substrate.
Furthermore from DE-41 28 766 a solar module is known comprising a number of solar cells interconnected into a solar cell string in which arrangement a transpar-ent substrate pane is provided with a screen printed conductor system. The rear contacts of the solar cells in this arrangement contact the screen print.conductor system within a solar cell string. The front contacts of the solar cells within a solar cell string are connected in parallel or in series mutually andlor to the rear contacts of neighbouring solar cells if required. A transparent cover pane is connected to the substrate pane, in the manner of a composite safety glass, using a connecting compound e.g. on basis of a plastic film or a cast resin. The cover pane also is provided with a screen printed conductor system which within a solar cell string contacts the front contacts of the solar cells in such a manner that front and/or rear contacts of neighbouring solar cells are electrically interconnected.
In a further design example according to Fig. 4 of the cited document the cover pane and the substrate pane form the individual panes of an insulating glass pane in which arrangement the solar cells are located in the air-filled interspace be-tween the panes. The panes in this arrangement are spaced at the required dis-tance -using spacers. Between the solar cell strings and the screen printed con-ductor systems of the cover pane and of the substrate pane electrically conducting KGSp001 hook-shaped or U-shaped spacer elements are arranged in such a manner that the solar cell strings are soldered to the screen print conductor systems not di-rectly but via the spacer elements. Obviously this design example is of secondary importance only as in the patent claims only a solar module with a connecting compound based on a plastic film or on a cast resin is referred to, i.e. the inter-space is filled with a cast resin mass according to the examples described with reference to the Figures 1 through 3.
The example according to Fig. 4 of the patent document cited above will hardly be economically feasible for various reasons as even small tensions differences between cover and substrate panes may cause glass breakages of the solar modules. Further the screen print conductor systems applied to both sides of the solar module impair the effectiveness of the solar irradiation which may cause considerable power loss. Due to the wiring of the solar cells on alternating faces a relatively high resistance is generated which further reduces the yield.
The known solar modules in which the solar cells are embedded in a synthetic film or in a cast resin mass are hardly suitable for recycling, since separation and elimination of glass substrates, synthetic films and/or cast resins and conductors being very demanding and thus so expensive that elimination of the elements as hazardous waste rather proves economically feasible.
It thus is the objective of the present invention to improve a solar module as men-tioned above in such a manner that a particularly simple arrangement results and that the solar modules in case of glass breakage or similar damages can be recy-cled, or re-used respectively, without difficulties.
This objective is met using a solar module presenting the characteristics according to the patent claim 1.
The inventive solar module presents the important advantage that the individual solar cells held therein can be exchanged in relatively simple manner, and that the KGSp001 solar cells still are very effectively protected against weather exposure such as solar irradiation, rain and similar influences. Tensions generated in the glass sub-strates due to such influences, owing to the unilateral connection of the solar cells to one glass substrate only, are not transmitted, or are transmitted to an insignifi-cant degree merely, to the solar cells. Owing to the simple lay-out of the inventive solar module also the energy spent in manufacturing the module is considerably lower compared to conventional modules, and thus manufacturing cost can be lowered by one third or more.
Further advantages of the present invention are explained in the dependent patent claims and in the following description in which the present invention is discussed in more detail with reference to a design example illustrated in schematic draw-ings. It is shown in:
Fig. 1 a schematic view of the lay-out of a solar module seen in a top view, Fig. 2 a section of the solar module along the line A-A according to Fig. 1, Fig. 3 a first arrangement of the conductors on the glass substrate, and Fig. 4 a second arrangement of the conductors.
In the Figures identical elements are referred to using the same reference signs, and explanations given first are valid unless stated otherwise specifically.
In Fig. 1 a top view of a solar module 1 is shown in purely schematic manner, with a support pane 2 laid out as a glass substrate and a congruent cover pane 3 laid out as a glass substrate, the two panes being spaced by a predetermined distance using a sealing spacer frame 4 indicated with dashed lines arranged at their bor-der zones. The glass substrate 2 is provided with conductor leads 6 to which the solar cells 7 are connected via soldered bridges. The conductors 6 are provided with contacting leads 8 and 9 extending to the outside and laid out as positive KGSp001 ports, and negative ports respectively. The solar-cells 7 as such can be known silicon or titanium cells, or photochemical cells respectively, as described e.g. in EP-B-0 525 070.
In Fig. 2 part of the cross-section along the line A-A according to Fig. 1 of the solar module 1 is shown. The solar cells 7 are fastened unilaterally to the conductor leads 6 on the support pane 2 using soldering bridges 10 at a distance from the two glass substrates 2 and 3. Additional elastic fastening elements such as bind-ing spots formed by a silicon adhesive also can be provided which are not shown further here. The solar cells 7 thus are arranged more or less freely in the air-filled interspace 11 between the two glass substrates 2 and 3. The support pane 2 as well as the cover pane 3 are made from a silicate glass, preferentially a colourless (white) glass, of a thickness of less than 5 mm. Depending on the application de-sired also a certain silicate quantity of recycled glass maybe used for manufactur-ing the glass substrates 2 and 3. On the inner faces of both substrates 2 and 3 a thin layer 12 and 13 each of a light reflecting paint presenting a light reflectance value of more than 62% is applied. This paint advantageously is a ceramic paint, also known as so-called glass pastes. For this purpose the ceramic paint is ap-plied to the glass substrates using the screen print method and in a tunnel kiln is baked onto the surface at a temperature exceeding 600 °C. Also the conductors 7 are printed onto the glass substrate 2 using an electrically conductive paste, pref-erentially a silver paste, and are baked in at a temperature exceeding 600 °C.
Baking of the ceramic paint and of the electrically conductive paste can be ef-fected in the same processing step. Instead of applying a ceramic paint coat the glass substrates 2 and 3 also can be subject to a surface treatment such as sand blasting or chemical etching in such a manner that on their outer surfaces they are rendered non-reflecting with a high diffusion effect. Other types of non-reflecting glass also can be applied for manufacturing the glass substrates 2 and 3. In order to equalise tensions in the glass substrates 2 and 3, the dimension of which can be e.g. 100 cm by 100 cm, the glass substrates are thermally pre-stressed, i.e.
they are heated in a tunnel kiln on rolls to a temperature. of about 600 °C to 700 °C
and then are shock-chilled in a cold air stream.
KGSp001 The spacer frame 4 furthermore contains a glass rod of rectangular cross-section serving as a spacer element, the thickness of which is chosen between about 6 and 16 mm, preferentially at about 8 mm. In the outer corners of the glass rod formed with the glass substrates 2 and 3 a seal 16 is provided made from butyl rubber. On the outer side of the glass spacer 15 then a further seal 17 is provided made from a rubber-elastic material such as silicon rubber, or e.g. a melt adhesive known under the trade mark "Bynel" or "hot melt", acting as a water moisture bar-rier for the solar module 1. However, seal 16 could be omitted and only seal could be provided. The spacer 15 also can be made from other materials, e.g.
from wooden slats of a hard wood, such as oak or beech wood. Also aluminium slats can be provided which are fastened between the glass substrates 2 and 3 using a melt adhesive ("hot melt"). Inside the solar module 1 furthermore a mo-lecular sieve 19 can be provided as a drying agent such as e.g. zeolite in order to reduce the residual humidity within the interspace 11 and to protect the solar cells 6 against corrosion. Additionally a humidity gauge 20 can be arranged in the inter-space 11 between the glass substrates 2 and 3, of which the electric contacts of which also can be extended to the outside via conductor leads which are not shown here. Using this arrangement humidity inside a solar module 1 can be monitored and any leaks in the solar module 1 can be detected.
In Fig. 4 an arrangement of a number of parallel conductor leads 6 is shown in the sense of an example each of which is soldered to an oblong solar cell 7 (shown with dashed lines). In the manufacturing process one single large silicon board is soldered onto the conductor leads 6 and subsequently the board is cut, using a laser beam, into the individual oblong solar cells 7. To the left and the right of the glass substrate or of the support pane 2 the two connecting ports (positive and negative) are indicated. In Fig. 4 a further arrangement of the conductor leads 6 is shown provided for the four solar cells 7 indicated with dashed lines.
It furthermore is feasible to mount the support pane 2 and the cover pane 3 not exactly congruent above each other using the spacer frame 4 but slightly offset. In KGSp001 this manner a plurality of solar modules 1 can be lined up seamlessly the ar-rangement forming a larger array. The solar modules lined up in this manner can form a wall, or a so-called weather coat for building facades, respectively, on roofs or similar parts of a building.
It has been proven that the energy consumed in manufacturing the inventive solar module 1 is in the order of 30 to 50 kWh per m2 the glass substrate thicknesses being chosen between 3.5 and 4.5 mm. This corresponds to about 2.2 kWh per kg of glass.
KGSp001

Claims

1. Solar module (1) with two glass substrates (2, 3) arranged opposite each other which in their border zone are interconnected spaced by a sealing spacer frame (4) and in the air-filled interspace (11) a plurality of solar cells (7) are ar-ranged at a distance with respect to the glass substrates (2, 3) in which ar-rangement the solar cells (7) are electrically interconnected via conductor leads, characterized in that the conductor leads (6) are applied exclusively to one glass substrate (2) and that the solar cells are fastened to the one glass substrate (2) by means of flexible spacer elements.

2. Solar module according to claim 1, characterized in that the solar cells (7) are fastened to the conductor leads (6) of the one glass substrate (2) by means of soldering bridges as flexible spacer elements.

3. Solar module according to claim 1 or 2, characterized in that the solar cells are additionally fastened to the one glass substrate (2) by means of elastic fas-tening elements, preferably as binding spots formed by a silicon adhesive.

4. Solar module according to one of claims 1 to 3, characterized in that the inter-space (11) is hermetically sealed from the outside room by a spacer frame (4) having a spacer element (15) and by an additional elastic seal (17).

5. Solar module according to claim 4, characterized in that the spacer element (15) is sealed by an elastic seal (16) of butyl rubber.

6. Solar module according to claim 4 or 5, characterized in that the elastic seal (17) comprises a silicon rubber or a hardened melt adhesive.

7. Solar module according to one of claims 1 to 6, characterized in that the glass substrates (2, 3) are made of silicate glass, preferentially of colourless (white) glass, and have a maximum thickness of 5 mm.

8. Solar module according to claim 7, characterized in that the glass substrates (2, 3) are coated on their whole surface with a light-reflecting paint presenting a light reflectance value of at least 62%.

9. Solar module according to the claim 8, characterized in that the light reflecting paint is a ceramic paint.

10. Solar module according to claim 7, characterized in that the glass substrates (2, 3) comprise a non-reflecting surface with a high diffusion effect.

11. Solar module according to one of claims 1 to 10, characterized in that the con-ductor leads (6) contain silver.

12. Solar module according to one of claims 1 to 11, characterized in that within the interspace (11) molecular sieves (19), in particular zeolites, are provided in order to reduce the residual humidity within the solar module (1).

13. Solar module according to one of claims 1 to 12, characterized in that within the interspace (11) a humidity monitoring gauge (20) is provided by means of which leaks in the solar module can be detected.