EP2795678A1

EP2795678A1 - Solar module with sealing element

Info

Publication number: EP2795678A1
Application number: EP12798666.9A
Authority: EP
Inventors: Mitja Rateiczak; Andreas Schlarb; Bernhard Reul; Lothar Lesmeister; Christoph Degen
Original assignee: Saint Gobain Glass France SAS; Compagnie de Saint Gobain SA
Current assignee: Saint Gobain Glass France SAS; Compagnie de Saint Gobain SA
Priority date: 2011-12-20
Filing date: 2012-11-29
Publication date: 2014-10-29
Also published as: WO2013092155A1

Abstract

The present invention relates to a solar module (20), at least comprising: laminated composite assembly comprising, arranged one above another, substrate (1), back electrode layer (3), semiconductor layer (4), front electrode layer (6) and substrate (2), at least two busbars (11), which are electrically conductively connected to the back electrode layer (3) and/or the front electrode layer (6), at least one contact hole (14) arranged in at least one of the substrates (1, 2), two contact elements (9), which are electrically conductively connected to the busbars (11) and are arranged in at least one contact hole (14), at least one sealing element (17) arranged between busbar (11) and contact hole (14), and the sealing element (17) has an opening (18) above the contact hole (14), wherein a connection housing (8) closes the contact hole (14) from an outer side (I, IV) of the substrate (1, 2).

Description

Solar module with sealing element

The invention relates to a solar module with sealing element. The invention also relates to a method for producing such a solar module and to the use of the sealing element.

Solar cells contain semiconductor material in all cases. Solar cells that require carrier substrates to provide sufficient mechanical strength and that can be manufactured in a continuous process are referred to as thin film solar cells. Due to the physical properties and the technological handleability, thin film systems with amorphous, micromorphous or polycrystalline silicon, cadmium telluride (CdTe), gallium arsenide (GaAs) or copper indium (gallium) sulfur / selenium (CI (G) S) are particularly suitable for solar cells.

Known carrier substrates for thin-film solar cells contain inorganic glass, polymers or metal alloys and can be designed as rigid plates or flexible films depending on layer thickness and material properties. Due to the widely available carrier substrates and a simple monolithic integration, large-area arrangements of thin-film solar cells can be produced inexpensively.

A method is known from EP 2 200 097 A1, in which a plurality of solar cell regions are connected in series in an integrated form by suitable structuring and interconnection of back electrode layer, semiconductor layer, and front electrode layer.

For external electrical connection, each thin-film solar module has two voltage connections. For this purpose, for example, two of the back electrode layer contacting bus bars are provided. The bus bars are usually contacted by a contact hole in the back of the solar module with a spring contact element and sealed with a junction box. Such junction boxes are known from DE 10 2005 025 632 A1 and DE 100 50 614 C1. At The junction boxes, the solar module with other solar modules can be connected in series to a module string or connected to an electrical load, which is often an inverter for converting the DC voltage generated in a suitable for the public grid AC voltage.

Furthermore, it is possible to observe a continuous increase in the series resistance in the case of thin-film solar modules, which, after a service life of several thousand operating hours, gradually changes into an at least approximately constant value. This aging leads to an undesirable deterioration of the efficiency of the solar module. It is believed that a major cause of this is the diffusion of water molecules into the semiconductor material of the solar cells.

US 2010/0175743 A1 discloses a solar cell in which a sheathed contact strip is introduced into the interior of the solar cell. The sheathing of the contact band serves as electrical insulation and as a moisture barrier.

In contrast, the object of the present invention is to further develop conventional solar modules in an advantageous manner, which is to be reliably and reliably avoided that water or moisture penetrate through the contact hole in the solar cell.

The object of the present invention is achieved by a solar module with a sealing element according to claim 1. Preferred embodiments will become apparent from the dependent claims.

A method for producing a solar module with a sealing element and a use of the sealing element are evident from further claims.

An inventive solar module comprises at least:

A laminated composite of superimposed first substrate, back electrode layer, semiconductor layer, front electrode layer and second substrate,

At least two bus bars electrically connected to the back electrode layer and / or the front electrode layer, At least one contact hole arranged in at least one of the substrates,

Two contact elements, which are electrically conductively connected to the bus bars and arranged in at least one contact hole,

At least one sealing element which is arranged between the bus bar and the contact hole and the sealing element has an opening above the contact hole, wherein

a terminal housing closes the contact hole from an outer side of the substrate.

The first substrate is preferably a carrier substrate and the second substrate is preferably a cover substrate. Solar modules and in particular solar modules with thin film solar cells differ in their layer arrangement in two configurations: In the so-called substrate configuration, the back electrode layer and the photovoltaically active semiconductor layer is deposited directly onto a carrier substrate. The carrier substrate is located on the side facing away from the light incident side of the solar module. In the so-called superstrate configuration, the front electrode layer is deposited directly on a cover substrate. The cover substrate is located on the side of the solar module facing the light.

The solar module according to the invention preferably comprises a solar module in substrate configuration. The carrier substrate has a back electrode layer on the front side and the back electrode layer is partially electrically conductively connected to a photovoltaically active semiconductor layer.

The photovoltaically active semiconductor layer according to the invention comprises at least one p-type semiconductor layer. Furthermore, an n-type front electrode layer is disposed on the semiconductor layer. The front electrode layer is transparent to radiation in the spectral range sensitive to the semiconductor layer.

The front side of the carrier substrate is connected to at least one intermediate layer with the back side of the cover substrate. In the substrate configuration, since the front side of the support substrate has a large area, the back electrode layer and the semiconductor layer has, the connection between the carrier substrate and intermediate layer over a large area over these layers.

An alternative embodiment of a solar module according to the invention takes place in superstrate configuration. In this case, a cover substrate is connected on its rear side via a front electrode layer to a photovoltaically active semiconductor layer. Since the rear side of the cover substrate has the photovoltaically active semiconductor layer and the back electrode layer over a large area, the connection between the cover substrate and the intermediate layer occurs over a large area over these layers.

An inventive solar module contains at least two bus bars, which are electrically conductively connected to the back electrode layer and / or the front electrode layer. The bus bars are contacted by two contact elements, wherein the contact elements are arranged in one or two contact holes. The contact holes are located in the cover substrate and / or in the carrier substrate. The contact holes are closed by connection housing, in the interior of which the contact elements are connected to external supply lines. The terminal housings are arranged on the front side of the cover substrate or the back side of the support substrate. The front in the sense of the present invention means the side of a substrate facing the light incidence, the back correspondingly, the side of a substrate facing away from the incidence of light.

Above each contact hole, a sealing element according to the invention is arranged. The sealing member is disposed between bus bar and the substrate having the contact hole. The sealing member has an opening disposed above the contact hole. This means that the opening of the sealing element is arranged in alignment with the contact hole. The sealing element is advantageously arranged directly on the substrate, which has the contact hole, or directly on a back electrode layer, which is located on this substrate. In this way, an all-round sealing of the contact hole is achieved.

The sealing element according to the invention advantageously contains elastic, moisture-proofing polymers, preferably elastomers and in particular polyisobutylene, polyisobutyleneisoprene, polysulfide, polyurethane, silicone or Combinations of it. The sealing element has the task of preventing the ingress of water and moisture into the interior of the solar module. Water and moisture lead to a deterioration of the efficiency of the solar module, which is reliably reduced by a sealing element according to the invention.

In an advantageous embodiment of the solar module according to the invention, the carrier substrate has a contact hole and preferably has two contact holes. The connection housings are accordingly arranged on the rear side of the carrier substrate. This has the particular advantage that no shadowing of the photoactive surface takes place through the connection housing. The sealing element is arranged between the carrier substrate and bus bar. The sealing element is designed such that it surrounds the contact hole all around.

In an advantageous embodiment, a contact hole according to the invention has a diameter of 1 mm to 20 mm, preferably of 2 mm to 10 mm and particularly preferably of 4 mm to 5 mm.

In an advantageous embodiment, the sealing element has an opening with a diameter a of 0.5 mm to 20 mm. In a preferred embodiment, the sealing element has an opening with a diameter a which is smaller than the diameter of the contact hole. The diameter a is preferably smaller by 0.1 mm to 3 mm than the diameter c. This has the particular advantage that the elastic material of the sealing element penetrates into the region of the contact hole and seals the edge region of the contact hole particularly reliably at the entry point.

In a further advantageous embodiment, the sealing element has a diameter c which is greater than the width d of the busbar. The diameter c is preferably 0.2 mm to 3 mm larger than the width d. Due to the overlap of the sealing element on the bus bar, a particularly reliable seal. The elastic material of the sealing element compensates for the unevenness between the bus bar and return electrode or front electrode and reliably seals the interior of the solar module.

In an advantageous embodiment, the sealing element is designed as a sealing plate with at least one opening. The sealing plate is parallel to the Substrates arranged, wherein the opening is arranged in alignment with the contact hole. The sealing plate can have any shape and is preferably square, rectangular, pentagonal, hexagonal or polygonal. The sealing plate is designed such that it surrounds the contact hole all around.

In an advantageous embodiment, the sealing element is an annular sealing disc. The opening is arranged in the center of the sealing disc and in alignment with the contact hole. Due to the symmetrical design of the sealing element is a particularly uniform and reliable seal. Furthermore, annular sealing disks, for example as simple stampings, can be produced inexpensively and easily processed automatically.

The thickness of the sealing member depends on the respective solar cell. In the substrate configuration, the sealing element advantageously has a thickness h of 0.03 mm to 0.5 mm. The thickness of the sealing element preferably corresponds approximately to the thickness of the busbar, more preferably the thickness of the busbar plus from about 10 μιη to 100 μιη. In the superstrate configuration, the thickness of the sealing element is advantageously about the thickness of the intermediate layer.

Cover substrate and carrier substrate are preferably made of prestressed, partially prestressed or non-prestressed glass, in particular float glass. In particular, the top substrate contains tempered or non-hardened low-iron soda-lime glass having a high transmittance to sunlight. Cover substrate and carrier substrate preferably have thicknesses of 1, 5 mm to 10 mm. The carrier substrate may advantageously also be configured as a film. The intermediate layers preferably contain thermoplastic materials, such as polyvinyl butyral (PVB) or ethylene vinyl acetate (EVA) or several layers thereof, preferably with thicknesses of 0.3 mm to 0.9 mm. The carrier substrate and the cover substrate are firmly bonded together via one or more intermediate layers under heat and pressure or under vacuum. The cover substrate may have on its side facing the light a special coating or texture, which reduces the reflection of light or the adhesion of dirt.

The bus bar is advantageously a metallic band and preferably an aluminum band. The bus bar, for example, has a thickness of 0.03 mm to 0.3 mm and a width of 2 mm to 16 mm. Aluminum has proven particularly suitable for such bus bars, since it has a good electrical conductivity and good processability to films. At the same time, the material costs are low. Other electrically conductive materials can also be used which can be processed into films. Examples of these are copper, tin-plated copper, gold, silver or tin and alloys thereof.

The bus bar is electrically connected to the rear and / or front electrode layer. The connection is preferably made by ultrasonic bonding or ultrasonic bonding, thermocompression bonding, welding, spot welding, soldering, clamping or gluing by means of an electrically conductive adhesive.

Busbars suitable for contacting back and / or front electrode layers in solar modules only have a total thickness of 0.5 mm at most. Such thin busbars can be embedded without difficulty between the carrier substrate and the cover substrate in the intermediate layer.

The present invention also comprises at least one single- or multi-part terminal housing with at least one electrical feed line and a contact element for forming an electrical line connection to the bus bar.

The connection housing is preferably made of an electrically insulating material. Thermoplastic plastics and elastomers, which are processed by injection molding, are suitable for industrial production of the connection housing. As thermoplastics and elastomers, for example, polyamide, polyoxymethylene, polybutylene terephthalate or ethylene-propylene-diene rubber are used. Alternatively, potting materials such as acrylate or epoxy resin systems can be used to make the connection housing. The terminal housing can be made of metal or another electrically conductive material with electrically insulating inserts.

Contact elements or spring contact elements made of metal are preferably used as contact elements. For the preferred use in a solar module is a solderless, clamping connection, since the contact point when used in buildings in the Usually no vibration is exposed. If required, the electrical line connection between contact elements can also be welded, bonded, soldered, glued or additionally secured.

The connection housing can serve as the basis for a connection plug or a connecting cable. In addition, it can accommodate other functional elements such as diodes or a control electrics.

The terminal housing is preferably adhesively attached and sealed on the back side of the carrier substrate or the front side of the cover substrate. The bonding is preferably carried out by means of a Kleerstrangs or adhesive tape with an adhesive based on acrylic, polyurethane or polyisobutylene.

The contact hole and thus the contact point of the bus bar are preferably located in the middle of the extension direction of the bus bar. Since the bus bar itself has an ohmic resistance, a voltage drop takes place during a current flow through the bus bar. With an electrical contact in the middle of the extension direction of the bus bar, a more homogeneous distribution of the current flow through the solar module and the bus bar is achieved than with an electrical contact at one end of the bus bar. In addition, the maximum current density in the bus bar in the region of the current tapping is lower than in the case of contacting at one end. This allows the use of bus bars with a smaller cross-sectional area, for example, with a smaller width. By using narrower busbars, the photovoltaically active surface of the solar module can be increased and the area-dependent power can be increased.

In an advantageous embodiment of the solar module according to the invention, the back electrode layer contains a metal, preferably molybdenum, titanium or tantalum nitrides. The back electrode layer may comprise a layer stack of different individual layers. The layer stack preferably contains a diffusion barrier of silicon nitride in order to prevent a diffusion of, for example, sodium from the carrier substrate into the photovoltaically active absorber layer. In an advantageous embodiment of the solar module according to the invention, the front electrode layer contains an n-type semiconductor, preferably aluminum-doped zinc oxide or indium-tin oxide.

In an advantageous embodiment of the solar module according to the invention, the p-type semiconductor layer of the photovoltaically active absorber layer contains amorphous, micromorphous or polycrystalline silicon, cadmium telluride (CdTe), gallium arsenide (GaAs) or copper indium (gallium) sulfur / selenium (CI (G) S).

In an advantageous embodiment of the solar module according to the invention, the gap between the carrier substrate and the cover substrate is sealed by an edge seal, preferably an adhesive based on acrylic, polyurethane or polyisobutylene. The edge seal prevents the penetration of air, water or moisture as an additional measure of the sealing element according to the invention and protects the sensitive semiconductor and metal layers from degradation and corrosion.

In a further advantageous embodiment of the solar module according to the invention, the interior of the connection housing is sealed by a sealant, preferably an adhesive based on acrylic, polyurethane or Polyisobutylen- or silicone-based. The sealant prevents the penetration of air, water or moisture into the interior of the connection housing as an additional measure of the sealing element according to the invention and in particular protects the electrical line connection between bus bar and contact element from degradation and corrosion.

In an advantageous embodiment of the solar module according to the invention, the electrical line connections between bus bar and back and / or front electrode layer and / or between bus bar and contact element soldering, welding, bonding or clamping connections. The electrical line connections can also have adhesive connections with an electrically conductive adhesive.

In an advantageous embodiment of the solar module according to the invention, the solar module on two bus bars, which are electrically contacted via two contact elements in two terminal housing through two contact holes. A bus bar is preferably connected to the positive voltage terminal of Solar module and the second bus bar connected to the negative voltage terminal of the solar module.

In an advantageous embodiment of the solar module according to the invention at least two bus bars on the back of the carrier substrate or the front side of the cover substrate in a common terminal housing with at least two contact elements are electrically connected. Both contact elements may be connected, for example via a two-pole cable or a two-pin plug with another electrical circuit. This embodiment is particularly advantageous because the substrates must be broken with only one contact hole. Single contact hole substrates are simpler and less expensive to manufacture than two-contact hole substrates, since the risk of chipping and breakouts during the drilling of the via holes is reduced.

The invention also encompasses a method for producing a solar module with a sealing element according to the invention, wherein at least

a) a first substrate with series-connected solar cells and at least two contact holes is provided,

b) a sealing element is arranged with an opening in the region of each contact hole (14),

c) a bus bar is placed over the contact hole,

d) the bus bar is electrically conductively connected to the return electrode, the connection taking place from the area of the contact hole,

e) the first substrate via an intermediate layer with a second

Substrate is laminated.

The first substrate is preferably a carrier substrate and the second substrate is preferably a cover substrate.

The invention also includes an alternative method for producing a solar module, wherein at least:

a) a second substrate is provided with series-connected solar cells, b) two bus bars are arranged on the second substrate and electrically conductively connected to the front electrode layer and / or the back electrode layer,

c) a first substrate having two contact holes and an intermediate layer arranged thereon is provided, wherein a recess is arranged in the intermediate layer in the region of the contact hole, d) a sealing element with an opening in the region of the contact hole and in the recess of the intermediate layer is arranged, e) first substrate and second substrate via the intermediate layer

are laminated together, wherein the contact holes are arranged below the bus bars.

In an advantageous embodiment of the method according to the invention, the bus bars are electrically conductively connected to the front electrode layer and / or the back electrode layer by ultrasonic bonding.

For the bonding of the cover substrate and the carrier substrate with an intermediate layer, the processes familiar to the person skilled in the art can be used with and without the preceding preparation of a precompound. For example, so-called autoclave processes can be carried out at an elevated pressure of about 10 bar to 15 bar and temperatures of 130 ° C. to 145 ° C. for about 2 hours. For example, vacuum bag or vacuum ring methods known per se operate at about 200 mbar and 130 ° C. to 145 ° C.

Preferably, the cover substrate and carrier substrate can be pressed with an intermediate layer in a calender between at least one roller pair to form a solar module according to the invention. Systems of this type are known for the production of laminated glazing and usually have at least one heating tunnel in front of a press shop. The temperature during the pressing process is for example from 40 to 150 ° C. Combinations of calender and autoclave processes have proven particularly useful in practice. Alternatively, vacuum laminators are used to produce the solar modules according to the invention. These consist of one or more heatable and evacuable chambers in which the cover substrate and carrier substrate are laminated within, for example, about 60 minutes at reduced pressures of 0.01 mbar to 800 mbar and temperatures of 80 ° C to 170 ° C.

The invention also includes the use of the sealing element for sealing the electrical contact point of a solar module, in particular a thin-film solar module.

In the following the invention will be explained in more detail with reference to a drawing. The drawing is a schematic representation and not to scale. In particular, the layer thicknesses of the bus bar and of the electrode layers are shown clearly enlarged here for the purpose of illustration. The drawing does not limit the invention in any way.

Show it:

FIG. 1 shows a cross-sectional drawing of a solar module according to the invention,

FIG. 2A is a cross-sectional drawing of a solar module according to the invention from FIG

1A along the section line A-A ',

FIG. 2B a schematic representation of a solar module according to the invention in the region of the connection housing with sealing element in a view onto the rear side of the carrier substrate,

FIG. 3 a schematic representation of a solar module according to the invention in a view onto the rear side of the carrier substrate,

Figure 4 is a cross-sectional drawing of an alternative embodiment of a

solar module according to the invention,

Figure 5 shows an embodiment of the method steps according to the invention with reference to a flow chart and

6 shows an alternative embodiment of the method steps according to the invention with reference to a flow chart. In the following figures, without limitation of the invention, an embodiment of a solar module 20 according to the invention with sealing element 17 is shown using the example of a thin-film solar module.

1 shows a cross-sectional view of a thin-film solar module 20 according to the invention with two series-connected two solar cells 20.1 and 20.2 in substrate configuration. The thin-film solar module 20 comprises an electrically insulating carrier substrate 1 with a layer structure applied thereto for forming a photovoltaically active absorber layer. The layer structure is arranged on the light entrance side front side III of the carrier substrate 1. The carrier substrate 1 consists here, for example, of glass with a relatively low light transmission, wherein equally other insulating materials with sufficient strength, as well as inert behavior compared to the process steps performed can be used.

The layer structure comprises a back electrode layer 3 arranged on the front side III of the carrier substrate 1. The back electrode layer 3 contains, for example, a layer of an opaque metal such as molybdenum and is applied to the carrier substrate 1, for example by sputtering. The back electrode layer 3 has, for example, a layer thickness of about 1 μm. In another embodiment, the back electrode layer 3 comprises a layer stack of different individual layers. The layer stack preferably contains a diffusion barrier in order to prevent a diffusion of, for example, sodium from the carrier substrate 1 into the semiconductor layer 4.

On the back electrode layer 3, a photovoltaically active absorber layer in the form of a semiconductor layer 4 is deposited, whose band gap is preferably able to absorb as large a proportion of the sunlight as possible. The semiconductor layer 4 contains a p-doped semiconductor layer, for example a p-type chalcopyrite semiconductor, such as a compound of the group copper indium di-selenide (CulnSe ₂ ), in particular sodium (Na) -doped Cu (InGa) (SSe) ₂ . The semiconductor layer 4 has, for example, a layer thickness of 500 nm to 5 μιη and in particular of about 2 μιη. On the semiconductor layer 4, a buffer layer, not shown here, is deposited, which contains, for example, a single layer of cadmium sulfide (CdS) and a single layer of intrinsic zinc oxide (i-ZnO). On the semiconductor layer 4 is a front electrode layer 6 applied, for example by vapor deposition. The front electrode layer 6 is transparent to radiation in the spectral range which is sensitive to the semiconductor layer 4 ("window layer"), in order to ensure only slight attenuation of the incident sunlight. The front electrode layer 6 can generally be referred to as a TCO layer (TCO = Transparent Conductive Electrode) and is based on a doped metal oxide, for example n-type, aluminum-doped zinc oxide (AZO). A pn heterojunction is formed by the front electrode layer 6, the buffer layer and the p-doped semiconductor layer, ie a sequence of different layers of the opposite conductivity type. The layer thickness of the front electrode layer 6 is for example 300 nm.

The layer system is subdivided by known methods for producing a thin-film solar module into individual photovoltaically active regions, so-called solar cells 20.1 and 20.2. The subdivision is made by incisions using a suitable structuring technology such as laser writing and mechanical processing, for example by lifting or scribing. The individual solar cells 20.1 and 20.2 are connected in series via a region of the back electrode layer 3.

An inventive thin-film solar module 20 has, for example, 100 series-connected solar cells and an open-circuit voltage of 56 volts. In the example shown here, both the resulting positive (+) and the resulting negative (-) voltage connection of the thin-film solar module 20 are guided over the back electrode layer 3 and contacted there electrically.

For protection against environmental influences, an intermediate layer 5 is applied on the front electrode layer 6, which contains, for example, polyvinyl butyral (PVB) or ethylene vinyl acetate (EVA). The thickness of the intermediate layer 5 is, for example, 0.76 mm. In addition, the layer structure of carrier substrate 1, back electrode layer 3 and semiconductor layer 4 is sealed via the intermediate layer 5 with a cover substrate 2. The cover substrate 2 is transparent to sunlight and contains, for example, tempered, extra-white low-iron glass. The cover substrate 2 has, for example, an area of 1.6 m × 0.7 m. The entire Thin film solar module 20 is mounted for mounting at the point of use in an aluminum hollow chamber frame, which is not shown here.

Due to the low current carrying capacity of the back electrode layer 3, the photovoltaically generated current is collected in so-called bus bars 11. The bus bars contain, for example, an aluminum strip having a thickness of 200 μm and a width d of 6 mm. The bus bars 1 1 are electrically connected in discrete areas with the return electrode 3.

The carrier substrate 1 has a contact hole 14 below the bus bar 1 1. In the contact hole 14, a connecting element 9 is introduced, which contacts the bus bar 1 1 electrically conductive. The contact hole 14 is covered to the outside by a terminal housing 8, which is connected for example by gluing to the back side IV of the substrate.

A sealing element 17 according to the invention is arranged between bus bar 1 1 and carrier substrate 1. The sealing element 17 according to the invention seals the interior of the solar module 20 against moisture, which could penetrate through the contact hole 14. The sealing element 17 contains a soft and flexible polymer which is suitable for sealing the region between the bus bar 1 1 and the carrier substrate 1. The sealing member 17 contains, for example, a butyl rubber such as polyisobutylene isoprene. The sealing element 17 is designed such that it penetrates into the edge region of the contact hole 14 and covers and seals the inner edge 16 of the back electrode layer 3. In this way, no water and moisture which penetrates via the contact hole 14 from the outside into the module to the back electrode layer 3 and the semiconductor layer 4 in the interior of the solar module 20 reach. The sealing element 17 has an opening 18. Within the contact hole 14, a contact element 9 is arranged and fixed by a connection housing 8. The contact element 9 extends through the opening 18 of the sealing element 17 and has an electrical line connection 10 to the bus bar 1 1.

In a solar module 20 without sealing element 17 according to the prior art, the penetrating moisture would lead to corrosion of the back electrode layer 3. The corrosion would begin in the region of the contact hole 14 and spread into the interior of the solar module 20. Such corrosion worsens the Efficiency of a solar module 20 over time. The polymer material of the intermediate layer 5 is not suitable to prevent the ingress of moisture since it is hygroscopic and binds water and moisture. The sealing element 17 according to the invention prevents the penetration of moisture, so that a moisture-related deterioration of the efficiency of the solar module 20 is reduced.

FIG. 2A shows a cross-sectional drawing of the solar module 20 according to the invention along the section line A-A 'from FIG. 1. FIG. 2B shows a schematic representation of a thin-film solar module 20 according to the invention in the region of the connection housing with sealing element in a plan view of the rear side IV of the carrier substrate 1.

The sealing member 17 advantageously includes an annular sealing disc 19 having a thickness of about the thickness of the bus bar, preferably from the thickness of the bus bar 1 1 plus from about 10 μιη to 100 μιη. In a particularly advantageous embodiment, the diameter a of the opening 18 is smaller than the diameter c of the contact hole 14. The contact hole has, for example, a diameter c of 5 mm. The opening 18 has a diameter a of, for example, 4 mm. This has the particular advantage that the soft material of the sealing element 17 extends into the contact hole 14 and the inner edge 16 of the back electrode layer 3 can seal.

In a particularly advantageous embodiment, the outer diameter b of the sealing member 17 is greater than the width d of the bus bar 1 1, so that the sealing disc protrudes beyond the lateral edges of the bus bar 1 1 and seals. The outer diameter b is for example 7 mm.

The bus bar 1 1 is in a plurality of surface areas 12.1, 12.1 ', 12.2, 12.2' electrically connected to the back electrode layer 3. The bus bar 1 1 is preferably connected to the back electrode layer 3 in 20 to 100 and, for example, 40 areas. The electrical line connection is done for example by ultrasonic bonding. FIG. 3 shows a thin-film solar module 20 in a view of the rear side IV of the carrier substrate 1. The carrier substrate 1 has two contact holes 14, which are arranged above the bus bars 11. The contact holes 14 are located, for example, in the middle of the longitudinal edge 25 of the thin-film solar module 20. This has the particular advantage that the voltage drop due to the ohmic resistance is reduced by the bus bars 1 1, resulting in a higher efficiency of the thin-film solar module. Through the contact holes 14, the bus bars 1 1 are electrically contacted, for example, by two contact elements 9, not shown here. Between the carrier substrate 1 and the bus bars 1 1 sealing elements 17 according to the invention are arranged. Above the contact holes 14 and on the back IV of the carrier substrate 1 terminal housing 8 are arranged.

FIG. 4 shows a cross-sectional illustration of a thin-film solar module 20 'according to the invention with two series-connected two solar cells 20.1' and 20.2 'in substrate configuration. The front electrode 6 is arranged on the rear side II of the cover substrate 2. The semiconductor layer 4 and the back electrode 3 are arranged on the front electrode 6 and connected in series. The cover substrate 2 is connected to the carrier substrate 1 via an intermediate layer 5. The materials and dimensions correspond, for example, to the embodiment of FIG. 1.

The bus bar 1 1 is connected to the front electrode 6. The contact hole 14 is arranged in the carrier substrate 1. The sealing member 17 is sleeve-like in this embodiment and configured so thick that it fills a recess 15 in the intermediate layer 5. This embodiment has the particular advantage that the penetration of water or moisture through the contact hole 14 in the intermediate layer 5 is reliably sealed.

The invention is in no way limited to the contacting of the back electrode layer 3. In an alternative embodiment of the thin-film solar module 20 according to the invention, the resulting positive and the resulting negative voltage connection of the thin-film solar module 20 are guided over the front electrode layer 6 and contacted there electrically. Alternatively, a voltage connection can be made via the back electrode layer 3 and the second voltage connection via the front electrode layer 6. FIG. 5 shows a flow chart of the method steps according to the invention for producing a thin-film solar module 20 with substrate configuration and arrangement of the connection housing 8 on the rear side IV of the carrier substrate 1. In the first step, a carrier substrate 1 with a structure of serially connected thin-film solar cells 20.1, 20.2 is provided Carrier substrate 1 at least 1 contact hole 14 and preferably has two contact holes 14. In a second step, a sealing element 17 is arranged in the region of each contact hole 14 on the inside III of the carrier substrate 1 and above the back electrode layer 3. The arrangement of the sealing element 17 can be automated or manual, for example.

In a third step, a bus bar 1 1 is applied along the longitudinal edge 25 of the solar module 20 and in the region of the contact hole 14 on the back electrode layer 3. The bus bar 1 1 extends above the sealing element 17 and fixes it on the back electrode layer 3 and thus on the carrier substrate 1.

In a fourth step, the bus bar 11 is electrically conductively connected to the return electrode 3. The line connection is preferably carried out in discrete surface areas 12.1, 12.1 ', 12.2, 12.2' starting from areas 12.1, 12.1 'which limit the contact hole 14 on both sides and then along the bus bar 1 1 outwards in the surface areas 12.2, 12.2'. Subsequently, further connections take place in surface areas not shown here along the busbar 11. The electrical line connection between the return electrode 3 and the bus bar 11 is preferably carried out by means of ultrasound bonding. The bus bar 1 1 is advantageously stretched during connection by externally applied forces in its direction of extent. The clamping compensates for an expansion of the busbar 1 1 during the connection process, as is done for example in Ultraschallverschweisen. If the space next to the contact hole is not sufficient to arrange two connecting tools at the same time, an alternative connection sequence can also be made in the surface areas. For example, the connection row is at 12.1, then 12.1 ', then 12.2, then 12.2', then 12.3, then 12.3 'and so on. Alternatively, the connection order may be at 12.1, then 12.1 ', then 12.2', then 12.2, then 12.3, then 12.3 'and so on. The bus bar 1 1, for example, in 40 areas with the Return electrode 3 connected. If the contact hole 14 is arranged in the middle of the busbar 1 1 with respect to its extension, then in each case 20 surface regions are arranged on both sides of the contact hole 14.

Alternatively, continuous joining methods, such as soldering, can be used, which connect the entire bus bar 11 to its full extension or, in large portions, to the back electrode layer 3.

FIG. 6 shows a flowchart of the method steps according to the invention for producing a thin-film solar module 20 with superstrate configuration and arrangement of the connection housing 8 on the rear side IV of the carrier substrate 1.

The invention provides a solar module 20, in particular a thin-film solar module, which enables a simple and cost-effective sealing of the layer structure in the interior of a solar module in industrial mass production. The diffusion of water molecules at the contact holes 14 can be reliably and safely prevented.

This result was unexpected and surprising to the skilled person.

Show it:

1 substrate, carrier substrate

2 substrate, cover substrate

3 back electrode layer

4 semiconductor layer

5 intermediate layer, thermoplastic intermediate layer

6 front electrode layer

8 connection housing

9 Contact element, spring contact element, supply line

10 electrical line connection between 9 and 11

11 busbars

12.1, 12'.1, 12.2, 12'.2 Connection between 1 1 and 3

14 contact hole

15 recess of the intermediate layer 5

16 inner edge of the back electrode layer 3

17 sealing element

18 opening in 17

19 annular sealing disc

20 solar module, thin-film solar module

20.1, 20.2, 20.1 ', 20.2' solar cell

25 longitudinal edge of the solar module 20 a diameter of the opening 18th

b outside diameter of 17

c diameter of the contact hole 14th

d width of the busbar 1 1

I Front side of the deck substrate 2, outside of the

Substrate 2

II Back side of the cover substrate 2

III front side of the carrier substrate 1

IV back of the carrier substrate 1, outside of the

Substrate 1

A-A 'cutting line

Claims

claims

1. Solar module (20) comprising at least

Laminated composite of superposed substrate (1),

Back electrode layer (3), semiconductor layer (4), front electrode layer (6) and substrate (2),

At least two bus bars (1 1), which are electrically conductively connected to the back electrode layer (3) and / or the front electrode layer (6),

At least one contact hole (14) arranged in at least one of the substrates (1, 2),

Two contact elements (9), which are electrically conductively connected to the bus bars (1 1) and arranged in at least one contact hole (14),

At least one sealing element (17) which is arranged between the bus bar (1 1) and the contact hole (14) and the sealing element (17) has an opening (18) over the contact hole (14), wherein a connection housing (8) forms the contact hole (14) 14) from an outer side (I, IV) of the substrate (1, 2) closes.

2. Solar module (20) according to claim 1, wherein the back electrode layer (3) on the substrate (1) is arranged and the substrate (1) has two contact holes (14).

3. Solar module (20) according to claim 1 or 2, wherein the sealing element (17) contains moisture-proofing polymers, preferably elastomers and in particular polyisobutylene, polyisobutyleneisoprene, polysulfide, polyurethane, silicone or combinations thereof.

4. Solar module (20) according to one of claims 1 to 3, wherein the sealing element (17) includes a sealing plate and preferably an annular sealing disc (19).

5. Solar module (20) according to any one of claims 1 to 4, wherein the sealing element (17) has a diameter (c) greater than the width (d) of the bus bar (1 1).

6. Solar module (20) according to one of claims 1 to 5, wherein the opening (18) of the sealing element (17) has a diameter (a) of 0.5 mm to 20 mm and preferably a diameter (a) smaller than a diameter (c ) of

Contact hole (14).

7. The solar module (20) according to any one of claims 1 to 6, wherein at least one intermediate layer (5) between the substrate (1) and back electrode layer (3) or substrate (2) and front electrode layer (6) is arranged and the intermediate layer (5) thermoplastic material, preferably polyvinyl butyral or ethylene vinyl acetate having a thickness of 0.3 mm to 0.9 mm.

8. Solar module (20) according to any one of claims 1 to 7, wherein the bus bar (1 1) contains a metal, preferably aluminum, silver or copper.

9. Solar module (20) according to one of claims 1 to 8, wherein the

Back electrode layer (3) is a metal, preferably molybdenum, titanium or

Tantalum nitride and / or the front electrode layer (6) contains an n-type semiconductor, preferably aluminum-doped zinc oxide or indium tin oxide.

10. Solar module (20) according to one of claims 1 to 9, wherein the semiconductor layer (4) amorphous, micromorphous or polycrystalline silicon, cadmium telluride (CdTe), gallium arsenide (GaAs) or copper-indium (gallium) sulfur / Selenium (CI (G) S) contains.

1 1. solar module (20) according to one of claims 1 to 10, wherein the electrical line connections between bus bar (11) and back electrode (3) and / or front electrode (6) a soldering, welding, bonding, clamping or

Have adhesive bonds.

12. A method for producing a solar module (20), wherein at least:

a) a substrate (1) with series-connected solar cells (20.1, 20.2) and at least two contact holes (14) is provided, b) a sealing element (17) with an opening (18) in the region of each

Contact hole (14) is arranged, c) a bus bar (1 1) is arranged above the contact hole (14), d) the bus bar (1 1) with the return electrode (3) is electrically conductive

is connected, wherein the connection (12.1, 12.1 ', 12.2, 12.2') takes place from the region of the contact hole (14),

e) the substrate (1) via an intermediate layer (5) with a substrate (2) is laminated.

13. A method for producing a solar module (20 '), wherein at least:

a) a substrate (2) with series-connected solar cells (20.1 ', 20.2')

provided,

b) two bus bars (1 1) are arranged on the substrate (2) and electrically conductively connected to the front electrode layer (6) and / or the back electrode layer (3),

c) a substrate (1) having two contact holes (14) and an intermediate layer (5) arranged thereon is provided, wherein a recess (15) is arranged in the intermediate layer (5) in the region of the contact hole (14),

d) a sealing element (17) having an opening (18) in the region of

Contact hole (14) and in the recess (15) of the intermediate layer (5) is arranged,

e) substrate (1) and substrate (2) via the intermediate layer (5) are laminated together, wherein the contact holes (14) below the bus bars (1 1) are arranged.

14. A method for producing a solar module (20,20 ') according to claim 12 or 13, wherein the bus bar (1 1) with the front electrode layer (6) and / or the back electrode layer (2) is electrically conductively connected by ultrasonic bonding.

15. A method for producing a solar module (20,20 ') according to one of

Claims 12 to 14, wherein the bus bar (1 1) by the contact element (9) with the terminal housing (8) via the contact hole (14) is electrically connected. Use of a sealing element (17) in a solar module (20) according to claims 1 to 1 1, preferably in a thin-film solar module.