WO2018058181A1

WO2018058181A1 - A solar module and a method of fabricating a solar module

Info

Publication number: WO2018058181A1
Application number: PCT/AU2017/051052
Authority: WO
Inventors: James Farnell; Christopher Smith; Paul Murray; Damion Milliken
Original assignee: Dyesol Ltd
Current assignee: Dyesol Ltd
Priority date: 2016-09-30
Filing date: 2017-09-27
Publication date: 2018-04-05
Anticipated expiration: 2019-03-30
Also published as: EP4173051A1; AU2017337293A1; AU2022246391B2; EP4173051A4; AU2022246391A1

Abstract

A method of preparing a substrate of a solar module is described including the steps of: providing a generally planar substrate; providing at least one aperture in the substrate; providing a conductive pathway which extends through the at least one aperture; and providing a hermetic seal associated with the at least one aperture.

Description

A SOLAR MODULE AND A METHOD OF FABRICATING A SOLAR MODULE

Technical Field

This invention relates to solar modules and to methods of fabricating solar modules. The invention particularly relates to improved sealing arrangements for use in solar modules.

Summary of the Invention

In a first aspect the present invention provides a method of preparing a substrate of a solar module including the steps of: providing a generally planar substrate; providing at least one aperture in the substrate; providing a conductive pathway which extends through the at least one aperture; and providing a hermetic seal associated with the at least one aperture.

The step of providing the hermetic seal may be carried out using a frit paste.

The frit paste may be electrically conductive and the step of providing the conductive pathway may be carried out by introducing the frit paste to the at least one aperture.

The method may further include the step of providing a cap member; and the step of providing the hermetic seal may be carried out by hermetically sealing the cap member to the substrate to overlie the at least one aperture.

The step of providing the conductive pathway may include the step of depositing conductive material through the at least one aperture.

The cap member may be at least partially recessed within the substrate.

The conductive pathway may be at least partially recessed within the substrate.

In a second aspect the invention provides a method of fabricating a solar module including the steps of: preparing a substrate in accordance with the first aspect of the invention; and incorporating the substrate as the back substrate in a solar module.

The method may further include the steps of providing a front substrate; and hermetically sealing the edges of the back substrate with the edges of the front substrate.

In a third aspect the invention provides a solar module including: a generally planar back substrate; the back substrate includes at least one aperture; a conductive pathway extending through the at least one aperture; and a hermetic seal associated with the at least one aperture.

The solar module may further include a cap member which overlies the at least one aperture.

The solar module may further include at least one junction box mounted to the back substrate in the vicinity of at least one aperture.

The solar module may further include a front substrate which is hermetically sealed about its edges with the back substrate. Brief Description of the Drawings

An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a cross sectional side view of a solar module;

Figure 2 is a plan view of the module of figure 1 ;

Figure 3 is a cross sectional side view of another embodiment of a solar module;

Figure 4 is a cross sectional side view of yet another embodiment of a solar module;

Figure 5 is a plan view of the module of figure 4;

Figure 6 is a cross sectional side view of another embodiment of a solar module;

Figure 7 is a plan view of the module of figure 6;

Figure 8 is a cross sectional side view of yet another embodiment of a solar module;

Figure 9 is a plan view of the module of figure 8;

Figure 10 is a cross sectional view of another embodiment of a solar module;

Figure 11 is a plan view of the module of figure 10;

Figure 12 is a cross sectional view of yet another embodiment of a solar module;

Figure 13 is a plan view of the module of figure 12; and

Figure 14 is a cross sectional view of another embodiment of a solar module.

Detailed Description of the Preferred Embodiment Referring to figures 1 and 2, a solar module 10a is shown including a planar glass back substrate 20. The back substrate 20 includes two apertures 26 and a conductive pathway which is also hermetic 50 extends through each aperture.

Apertures 26 are hermetically sealed by a sealing arrangement which includes a cap member in the form of capping substrate, for example glass or metal sheets or films, 60 and two regions of hermetic sealing material 40, 42. The hermetic conductive pathways 50 extends between the regions of sealing material 40, 42.

The module of figures 1 and 2 is fabricated by a method which commences with preparation of the back substrate 20. A panel of glass is cut to size and the apertures 26 are formed in the substrate by drilling, for example by mechanical drill bit, sand blasting, laser perforation, or other such suitable technique, the substrate 20.

Patterned regions of conductive coating are applied to form the inner 51 and outer 53 regions of the conductive pathways. The regions 51, 53 are electrically joined by depositing a region of conductive material 52 through the apertures 26.

The rectangular regions of hermetic seal material 40, 42 in the form of commercially available glass loaded frit paste are then applied to the back substrate 20 and the capping substrate respectively, by suitable coating and deposition methods such as (silk-)screen printing, stencil printing, aerosol jet printing, inkjet printing, dispensing, gravure printing, rotogravure printing, flexographic printing, lithographic printing, or slot die coating, or other such suitable process. Conductive region 50 is applied to overlie the region 40 of glass frit material by a suitable coating and deposition method such as (silk-)screen printing, stencil printing, aerosol jet printing, inkjet printing, dispensing, gravure printing, rotogravure printing, flexographic printing, lithographic printing, or slot die coating, or other such suitable process, so as not to disrupt the integrity of hermetic seal material 40, 42.

The capping substrate 60 is then brought together with the back substrate and heat is applied by placing the assembly in an oven for a period of time to cure the glass frit material 40, 42. After curing and cooling, the capping substrate 60 is hermetically sealed to the back substrate 20. The process sequence may optionally involve first thermally curing the hermetic frit sealing material 40 or 42 on its relevant substrate 20 or 60 prior to deposition of hermetically sealing conductive material 50 and subsequent curing of hermetic sealing conductive material 50 with or without additional adjacent non-conductive hermetic sealing material. Further, conductive materials 51, 52, 53, 50 and the conductive material within aperture 26 may be the same material, or different material, and may be applied at the same time, or in sequential steps with or without thermal processing between one or more or all of the deposition steps.

The front substrate of the solar module 30 is prepared in a known fashion to provide one or more photovoltaic regions 70 on the inside surface of the front substrate 30. The front substrate is then joined to the back substrate in a known fashion. An edge seal 22 is provided about the periphery of the module. Z-connects 24, 25 provide an electrical connection between the photovoltaic region 70 to the conductive pathways 51. Ideally, edge seal 22 is hermetic, for example a glass frit based seal, but can be any other suitably long-term stable edge sealing configuration such as desiccant filled butyl rubber or related chemistries or other such systems known to those skilled in the art.

The resulting assembly 10a therefore provides for electrical connections to the photovoltaic regions of the solar module without the need for conductive pathways to extend through the edge seal of the module, and while maintaining hermeticity in this rear junction box connection region, thereby improving the long-life prospects for the module over existing configurations.

An assembly according to figure 1 was fabricated in a laboratory and subsequently subjected to helium leak testing which verified the efficacy of the hermetic seal.

Referring to figure 3, another embodiment of a solar module 10b is shown. This embodiment differs from module 10a in that only one region of insulating hermetic sealant 42 is provided. The embodiment in figure 3 provides the advantages of simpler manufacturing/processing and accommodation of different underlying conductivity requirements, spatial layouts and electrical and/or mechanical loading.

Referring to figures 4 and 5, yet another embodiment of a solar module 10c is shown. This embodiment differs from those previously described in that no separate insulating hermetic sealant is used. Instead, two regions of conductive hermetic sealant 44 in the form of a commercially available metal loaded glass frit paste are utilised. The metal may be silver, copper, aluminium or any other metal which is suitably electrically conductive for the cross sections, widths and distances required at the current loadings produced by the module, and which is compatible with the thermal processes used for hermetic sealing and the mechanical strength needs of the module assembly during service. This enables the sealing and conductivity to be provided by a single material, which has advantages in simpler manufacturing/processing, less material interactions/compatibility considerations and a larger conductive cross section.

Referring to figures 6 and 7, another embodiment of a solar module lOd is shown. This embodiment differs from module 10c in that regions of conductive hermetic sealing material 46 are used to hermetically seal the apertures 26 in the back substrate as well as provide the conductive pathway. This removes the need for a capping substrate, which provides the advantages of an almost flush surface on the back substrate, simpler manufacturing/processing and a lower weight.

Referring to figures 8 and 9, yet another embodiment of a solar module lOe is shown. The embodiment in Figure 8 demonstrates the use of a back substrate that has in-built or pre-deposited conductive regions 48 that do not form a hermetic seal. A number of methods of fabricating the in-built or pre-deposited regions are possible, including deposition of a non-hermetic conductive material via processes such as (silk- )screen printing, stencil printing, aerosol jet printing, inkjet printing, dispensing, gravure printing, rotogravure printing, flexographic printing, lithographic printing, or slot die coating, along with appropriate curing regimes (thermal, UV, etc.) as required for the material and process combination. The use of in-built or pre-deposited conductive regions in this embodiment can also be employed in variations of the embodiments of figures 3 and 4.

Referring to figures 10 and 11, yet another embodiment of a solar module lOf is shown. This embodiment differs from module 10b in that the conductive hermetic pathway, insulating hermetic sealant and capping substrate are located in a recess 61 within the back substrate, which provides the advantages of a flush surface on the back substrate, simpler manufacturing/processing and a lower weight.

Referring to figures 12 and 13, yet another embodiment of a solar module lOg is shown. This embodiment differs from module lOd in that the conductive hermetic sealing pathway is located in a recess 62 within the back substrate, which provides the advantages of a flush surface on the back substrate, simpler manufacturing/processing and a lower weight. This requires a recess of less depth in the back substrate than in module lOf.

Referring to figure 14, another embodiment of a solar module lOh is shown. This embodiment differs from module lOd in that the thru holes are in an alternative configuration. A similar alternation of the thru hole configuration is also possible for modules 10a, 10b, 10c, lOe, lOf and lOg.

In some embodiments, for processing efficiency, the sealing of the back substrate to the capping substrate can occur after or at the same time as the back substrate is sealed to the solar module. This is especially synergistic if the edge sealing is achieved in the same manner as the hermetic seal. Specifically, low temperature laser sintering of a hermetic glass frit, conductive or non-conductive, provides a method of sealing the edge seal and capping substrate in a single process.

In various embodiments the back substrate and capping substrate may be formed from rigid materials (glass, ceramic, aluminium, steel or other metals, etc), flexible (polymer, flexible glass, metal foil, etc), conductive (transparent conductive oxide coated glass, metals, metal foils, coated polymers, etc) or nonconductive (glass, polymer, coated metal foils, etc) materials. In the case of a substrate formed from a conductive material such as metal it may be necessary to add an additional electrical isolation layer. If the conductive pathways are to be passed through non-glass interfaces or intermediate resistivity substrates (such as re concrete) then secondary insulation may be required.

When embodied on a substrate with a conductive coating, the conductive coating can be either removed in a pattern to isolate and distinguish multiple conductive pathways within the hermetically sealed region, across the hermetic seals and/or outside the hermetically sealed region; or the conductive coating can be likewise pattered during deposition.

When embodied on a conductive substrate, the invention also encompasses an insulating layer or coating which can also be patterned to isolate and distinguish multiple conductive pathways.

Embodiments of the invention can be integrated into the industry standard backsheet/s with or without integrated external contacts (Tedlar, Nylon, etc). Junction boxes may be affixed to the back faces of solar modules to connect with the conductive pathways which are accessible at the rear of the module.

This invention can apply to any solar module in which high quality environmental sealing is required to ensure long product life in service. This encompasses all types of solar modules, including:

• Mono-crystalline silicon

• Poly-crystalline silicon

• Amorphous silicon

• Gallium-arsenide and variants

• Cadmium-telluride

• Copper-indium-selenide and variants

• Copper-indium-gallium-selenide and variants

• Dye sensitised solar cells, both liquid and solid

• Organic photovoltaics

• Perovskite photovoltaics

• Kesterite solar cells such as copper-zinc -tin-sulfide

However, the invention is most suitable for those solar cell technologies which have a sensitivity to atmospheric moisture and/or oxygen, such as copper-indium- selenide and variants, copper-indium-gallium-selenide and variants, dye sensitised solar cells (both liquid and solid), organic photovoltaics and perovskite photovoltaics.

It can be seen that embodiments of the invention provide at least one of the following advantages:

• A back mounted junction box to be connected to an edge encapsulated solar module without compromising the edge sealing or back cover glass integrity.

• Embodiments of the present invention provide specific advantages in

processing, as the back substrate can be fully processed and sealed prior to the incorporation with the solar module encapsulation. This allows for processing steps for the back substrate without the limitation of compatibility with the solar modules, such as high temperature sintering, UV curing or solvent exposure. Any reference to prior art contained herein is not to be taken as an admission that the information is common general knowledge, unless otherwise indicated.

Finally, it is to be appreciated that various alterations or additions may be made to the parts previously described without departing from the spirit or ambit of the present invention.

Claims

A method of preparing a substrate of a solar module including the steps of: providing a generally planar substrate;

providing at least one aperture in the substrate;

providing a conductive pathway which extends through the at least one aperture; and

providing a hermetic seal associated with the at least one aperture.

A method according to claim 1 wherein the step of providing the hermetic seal is carried out using a frit paste.

A method according to claim 2 wherein the frit paste is electrically conductive and the step of providing the conductive pathway is carried out by introducing the frit paste to the at least one aperture.

A method according to claim 1 further including the step of providing a cap member; and

the step of providing the hermetic seal is carried out by hermetically sealing the cap member to the substrate to overlie the at least one aperture.

A method according to any preceding claim wherein the step of providing the conductive pathway includes the step of depositing conductive material through the at least one aperture.

A method according to any preceding claim wherein the cap member is at least partially recessed within the substrate.

A method according to any preceding claim wherein the conductive pathway is at least partially recessed within the substrate.

A method of fabricating a solar module including the steps of:

preparing a substrate in accordance with any one of claims 1 to 7; and incorporating the substrate as the back substrate in a solar module.

A method according to claim 8 further including the steps of providing a front substrate; and hermetically sealing the edges of the back substrate with the edges of the front substrate.

A solar module including:

a generally planar back substrate;

the back substrate includes at least one aperture; a conductive pathway extending through the at least one aperture; and a hermetic seal associated with the at least one aperture.

A solar module according to claim 10 further including a cap member which overlies the at least one aperture.

A solar module according to either of claims 10 or 11 further including at least one junction box mounted to the back substrate in the vicinity of at least one aperture.

A solar module according to any one of claims 10 to 12 wherein the module further includes a front substrate which is hermetically sealed about its edges with the back substrate.