The key innovation in WYSIPS® photovoltaic components takes on a technological challenge by combining high energy performance and transparency. How, and for what kind of opportunities? VP Technology & Transport Jean-Luc Ledys explains…
SP : In 2011, Sunpartner Group made headlines by unveiling Wysips®, a photovoltaic component strip boasting 70% transparency. A year later, the transparency has reached 90%! What is at stake behind this leap in performance?
Jean-Luc Ledys: Well let’s start with a small detour regarding « how » we obtain this transparency. I remind you that it gives our component strips the possibility of turning any surface into a potential solar and artificial light power producer, without changing its appearance.
Yet this transparency is achieved through an optical device that masks the photovoltaic material, which is itself miniaturised into micro-strips. The whole challenge for our technology consists in finding the optimal compromise between yield and transparency, given that the whole surface is not made of photovoltaic material.
Moreover, by acting upon three parameters – PV material, cell design and optical device – we can adapt the yield-to-transparency ratio according to the sector concerned.
For it so happens that this optimal compromise is not the same with respect to the applications involved. Solar windows or display panels will use solutions that seek a 60% to 80% transparency, while on the other hand, everything that has to do with digital screens is more demanding.
Take phones, smartphones, e-books, tablets etc.: manufacturers are busy conducting improvement programmes for the visual quality of their screens, and this implies a minimal impact on additional devices like touchscreens or the WYSIPS® module. That was the reason we started working on solutions providing 90% transparency.
How are you positioned with regard to worldwide research on transparent PV cells?
J.L.L. : It should be understood that we do not design photovoltaic cells: we buy and we process the materials from the best industrialists on the market so as to guarantee top performance.
Regarding research that is underway on those materials, laboratories are studying polymers which, while not being opaque to light, do not have a degree of transparency comparable to that obtained with our WYSIPS® technology. Indeed, that research has achieved up to 70% transparency under non-industrialised conditions, while we obtain 90% in the industrial phase.
Having said that, we should remember that those semi-transparent materials made from polymers aim at energy producing applications in the building trade, such as photovoltaic windows. To date, energy conversion yields remain limited to between 2% and 4% in the laboratory. But there is no doubt that they will eventually attain better performance. When they do, they could prove perfectly suitable for Wysips technology, and help us further improve our rate of transparency for those applications that require it.
What is your technological roadmap by 2014?
J.L.L. : Basically, we are focusing on photovoltaic materials performance. Our current solutions are based on amorphous silicon which we get from the best suppliers. We shall carry on according to what yields are required by the applications concerned, and to what is available.
At that point we shall go for materials of the polymorph silicon kind; or better still in terms of yield, we shall look at CIGS alloy (copper indium gallium selenide); not to mention organic materials too, whose texture will help us to print our components.
Meanwhile, we shall continue working on PV cell design and processes, as well as on the optical device, so as to optimise energy production.
We can already confidently expect increased energy performance from our technology by 2014, reaching 3 milliwatts per square centimetre – representing a 3% conversion yield -, for 90% transparency.
For 70% transparency, the yield will more than double over the same period, as shown on the diagram below.
SP : How are you positioned with respect to other PV technology?
J.L.L. : Sunpartner Group is all about seizing the opportunities offered by the progress going on in photovoltaic materials. We shall adapt our design and our PV cell production process to what the suppliers are offering, which is something that is bound to change in the coming years.
And this also means that we shall, in exchange and thanks to our own development, provide those same materials manufacturers and suppliers with new and diversified applications outlets, and thus with production opportunities on a significant scale.
SP : One final word about the Wysips Textile® and Wysips Glass® programmes…
J.L.L. : I reminded you that our WYSIPS® technology makes it possible to turn a single-function surface into a multi-function one without affecting its outward appearance – the new function being, in this case, the production of energy.
In that regard, the programmes involving light energy (solar + artificial lighting) textiles and windows are a logical extension of our initial developments.
They involve a highly innovative approach, obviously patented, and obviously fully confidential… and one whose work programme will last for dozens of months.
This will be done through collaborative efforts with industrialists within the sector, and we can expect the initial solar textile and window products to come on the market within the next three to five years.
There are multiple targeted applications: all glass surfaces on buildings, cars, trains, airplanes and all other means of transport… As for textiles, the field is also huge, whether in the building trade or other sectors.
The market is demanding those new functionalities. Tomorrow’s world begins today; given its stockpile of on-board items, it will need clothing, luggage etc. capable of generating the energy used to power all of those nomad electronics!