Nachrichten, Termine, Experten
10/19/2026 15:52
Solar glass is used as a transparent weather shield and substrate for photovoltaic modules. A coating technology developed by EXXERGY aims to increase the strength of solar glass to such an extent that significantly thinner panes become possible. While maintaining the mechanical properties, the glass mass could be reduced by up to 40%. In collaboration with the Fraunhofer Institute for Silicate Research ISC, the process is being further scaled up. At Glasstec 2026, the EXXERGY subsidiary EXXOSQEL will present a demonstrator from this joint development in Hall 11 at Booth E12.
The expansion of photovoltaics is a key component of the energy transition. At the same time, the production of PV modules also requires significant amounts of raw materials and energy. Low-iron solar glass plays a major role in this; it protects the cells and the electrically conductive components in the module from the elements while also ensuring high light transmission. The stability requirements for large-area PV modules are also demanding. Depending on the design and mechanical requirements, the mass per unit area of today’s PV modules typically ranges from about 11 to 13 kg/m²; modules designed for particularly high durability can reach values of up to about 16 kg/m². This consumes resources, incurs transportation costs, and requires correspondingly massive substructures for installation. Less glass therefore means less material usage and process energy, as well as reduced weight during transport and installation.
Thin, but stable?
One possible solution is to use thinner glass for solar modules. Accounting for 70 to 80% of the weight, glass is one of the most important factors in today’s PV modules in terms of material usage and module weight. Reducing the glass thickness accordingly saves weight and resources during manufacturing, as well as during transportation and installation. In addition, less energy is consumed during production. The challenge lies in increasing the glass’s strength to the point where even thin glass panes are stable enough to withstand hail, snow, and wind loads.
Thermal tempering reaches its limits with thin glass
A standard method for increasing the stability and fracture resistance of flat glass is thermal tempering. Controlled cooling during the production process, achieved by blowing cold air onto the glass, results in a defined thermal stress. This creates compressive stresses on the surface that inhibit the propagation of cracks. The glass becomes more break-resistant. Glass toughened in this way is used, for example, as single-pane safety glass in architectural applications, automotive manufacturing, or the furniture industry. For solar glass, 3.2 mm is a common nominal thickness; however, further reduction to 2 mm and below can only be achieved to a limited extent—if at all—using conventional thermal tempering.
Another treatment, which is particularly suitable for thin glass, is so-called chemical toughening. Here, surface tension is achieved chemically through ion exchange at the glass surface, in which sodium ions are replaced by potassium ions. This generates high compressive stresses in the layer of glass near the surface. One advantage of this method is that it produces less optical distortion than thermal tempering. However, the process is relatively complex, energy-intensive, and time-consuming, and its application on a large scale is limited.
Crack Healing Through a New Coating
Since manufacturing-related microcracks in flat glass play a decisive role in the glass’s strength, this is where the new process from EXXERGY and EXXOSQEL comes into play. With a combination of a new coating material and an adapted application method, surface defects can not only be covered over but, in part, as it were, healed. “Specifically, we create a three-dimensionally cross-linked composite from several components, whose matrix forms covalent bridges within the microcracks at the molecular level after the coating is applied,” explains Thomas Sauer, CEO of EXXOSQEL. This significantly increases the energy required to break the glass. Laboratory tests have already shown significant improvements in glass strength: After several iterative improvements to the formulations and processes, the strength of 2-mm-thick glass samples was increased by a factor of up to 4, and that of 1-mm-thick glass samples by a factor of up to 7, in each case compared to a non-tempered reference. The company estimates that thinner glass substrates could significantly reduce material usage, energy consumption, and CO₂ emissions. A reduction in glass mass of up to 40% could, depending on the module design, reduce the total mass of the module by around 30%. For a heavy module weighing, for example, 16 kg/m², this would correspond to a reduction to around 11 kg/m². The supporting structures could also be designed to be correspondingly lighter due to the lower static loads.
From the laboratory scale to the prototype
The next steps in development aim to transfer the technology from small glass samples to larger formats and ultimately to commercial-scale solar modules. To date, material and coating development has been carried out primarily by EXXERGY in close collaboration with Fraunhofer ISC. “The steps from a laboratory prototype to a large solar module require a great deal of expertise in scaling up material synthesis, application technology, and module manufacturing,” says Thomas Sauer. Fraunhofer ISC contributes its experience in syntheses up to the 100-liter scale and in coating application. Here, both partners are working closely together on material formulation and technology development. The researchers in Würzburg are also supporting the automation of the coating process: “We want to design the application of the new coating so that it can be easily integrated into existing manufacturing processes,” says Dr. Ferdinand Somorowsky, head of coating technology at Fraunhofer ISC, emphasizing the application aspect. EXXERGY is also collaborating with the Fraunhofer Center for Silicon Photovoltaics (CSP) in Halle to adapt the technology to module formats and test larger formats. Together, the partners are now driving forward the next step in scaling up the technology. Thomas Sauer explains what this means: “With our coating development for flat glass, we are now moving toward TRL 6 on the internationally accepted Technology Readiness Level scale. This means we have already successfully produced the first prototypes in standard dimensions under real-world conditions, and stress tests are currently underway. With the next development step, we are aiming for TRL 7 and thus for the actual operating environment.” EXXOSQEL is now preparing the next steps regarding industrialization and marketing.
Project Information
—
The work to date has been funded, among other sources, by the Federal Ministry for Economic Affairs and Energy through the projects Green Solar Modules (grant number 03EE1161E) and Green Solar Modules Glass II (grant number 03EEM1003), as well as financed by EXXERGY, a company affiliated with EXXOSQEL.
Ferdinand Somorowsky
Fraunhofer Institute for Silicate Research ISC
Head of Chemical Coating Technology
ferdinand.somorowsky@isc.fraunhofer.de
Thomas C. Sauer
EXXOSQEL GmbH
Management
info@exxosqel.com
Fig.1 A coating for healing microcracks—EXXOSQEL and Fraunhofer ISC aim to enable light-er, shatter- ...
Source: istock
Copyright: © EXXOSQEL
Fig.2 Fraunhofer expertise for upscaling material synthesis and application
Copyright: © EXXOSQEL
Criteria of this press release:
Business and commerce, Journalists, Scientists and scholars
Chemistry, Energy, Environment / ecology, Materials sciences, Mechanical engineering
transregional, national
Research projects, Transfer of Science or Research
English
Fig.1 A coating for healing microcracks—EXXOSQEL and Fraunhofer ISC aim to enable light-er, shatter- ...
Source: istock
Copyright: © EXXOSQEL
Fig.2 Fraunhofer expertise for upscaling material synthesis and application
Copyright: © EXXOSQEL
For download
For download
Start date
End date
You can combine search terms with and, or and/or not, e.g. Philo not logy.
You can use brackets to separate combinations from each other, e.g. (Philo not logy) or (Psycho and logy).
Coherent groups of words will be located as complete phrases if you put them into quotation marks, e.g. “Federal Republic of Germany”.
You can also use the advanced search without entering search terms. It will then follow the criteria you have selected (e.g. country or subject area).
If you have not selected any criteria in a given category, the entire category will be searched (e.g. all subject areas or all countries).
