From pv journal 05/23.
It is a declare as outdated as the trendy photo voltaic business: Not all roofs or different surfaces are appropriate for conventional, glass-encapsulated photo voltaic modules. Consequently, particular modules are wanted to beat any obstacles. The merchandise provided embody a variety of module sizes and dimensions, light-weight variations for roofs that can’t stand up to glass hundreds, adhesive set up to forestall penetration of the surfaces of roof, and even curved or versatile modules that may comply with the contours of the roof.
The logic behind this pondering is evident. To realize the targets of fast and widespread decarbonization, it’s mandatory to put in photo voltaic on as many usable surfaces as doable. To some extent there’s latest proof to recommend that that is understood. One instance is the photo voltaic balcony, which is turning into extra frequent in Europe as EU states concentrate on an power disaster fueled by Russia’s invasion of Ukraine.
Going again nearly a decade, the primary photo voltaic know-how that tried to fulfill the necessity for versatile and light-weight purposes was skinny movie – copper indium gallium selenide (CIGS) photo voltaic particularly. Producers comparable to World Photo voltaic and MiaSolé intend to introduce versatile modules that present comparatively good conversion effectivity – 10.6% and 14.3%, respectively – in a versatile format.
Each firms struggled to compete, nevertheless, and have been successfully shut down because of their acquisition, in 2013, of Hanergy – an organization whose shares have been suspended from buying and selling on the Hong Kong trade for 3 years with out but the enterprise withdrew the inventory and went non-public. .
What a distinction a decade makes. On the Solarex commerce present in Istanbul, Sunport Energy, a Chinese language steel wrap-through (MWT) producer, showcased its S-Flex module – a light-weight, versatile product that achieves 21.8% effectivity and an influence output of 365 W to 385 W.
“In Turkey, versatile modules are very new so the response has been excellent,” mentioned Sunport’s advertising director, Katrina Xu, as present attendees stopped by the corporate’s sales space to take a look at the S-Flex. “In March, we have been at Photo voltaic Options and there was lots of curiosity as a result of in Europe the residential market is rising effectively. In Germany, they wish to use these modules in balcony purposes.
This 12 months noticed Sunport emerge onto the worldwide stage after greater than two years of isolation on account of China’s strict Covid-19 containment measures. “It’s troublesome for us to go exterior China,” Xu mentioned. “With a brand new product, we have to discuss on to prospects. And for the final three years we’ve not been in a position to try this.”
The MWT know-how deployed in S-Flex is a back-contact cell during which laser-drilled holes, or vias, are shaped by way of the wafer, enabling the entrance metallization to wrap by way of the opening to the again aspect. The cell itself, on this case, is a PERC (passivated emitter rear contact) machine. The cells are wrapped in a light-weight however robust polymer materials – “2D encapsulation” within the parlance of the corporate – leading to a 5.7 kg module that may accommodate a most bending radius of 0.3 m.
As a back-contact know-how, MWT eschews conventional busbar cell interconnection to as a substitute use copper frontside metallization and a conductive backsheet. “This makes the know-how extra appropriate for versatile encapsulation,” Xu mentioned. “Whenever you make the ribbon of the photo voltaic cell, while you bend the module, the welding level has stress that simply causes micro cracks. And the busbar-free design reduces the module shading space to extend the module conversion effectivity. We have now self-made copper conductive backsheet. So we do not have welding stress. And for those who bend it, we do not have issues just like the busbar module.”
Coupling MWT with versatile encapsulation seems to be a neat trick. Suntech pioneer Zhengrong Shi believes this, saying that “as a result of the tabbing is on the identical floor, you do not have to consider bending.” Since 2018, Shi has promoted “glassless” mild modules below the Sunman Vitality model.
Not surprisingly, the 2 firms are charting the identical course, with Sunport CEO Fengming Zhang the previous Suntech chief scientist and each Zhang and Shi alumni of the College of New South Wales. Shi mentioned Sunman had shipped 200 MW of light-weight crystalline silicon modules in 2022 and anticipated it to “not less than double” this 12 months.
By way of cargo, Sunport has larger ambitions. The corporate targets S-Flex gross sales of between 300 MW and 1 GW this 12 months. “An important market is Europe however we’re additionally Brazil, Japan, and Australia,” mentioned Sunport’s Xu.
Advantages of back-contact
Conductive backsheets provide further advantages. Endurans, a supplies provider, ships conductive backsheets, primarily to module producers in Europe and North America. Lawrence Theunissen, the enterprise director for the fabric, likens it to printed circuit boards in the way in which that it conducts electrons “in line with the structure of the cells within the module.” Greater than the versatile modules themselves, this performance gives “flexibility” to module makers, he mentioned.
“One other manner to take a look at flexibility – and that is one other big advantage of utilizing a conductive backsheet – is to make use of flexibility within the placement of your electrical sample,” he defined. “Often, conventional modules embody a few strings contained in the module – a matrix structure – so it is not sophisticated.”
Conversely, Theunissen says, module producers can recommend Endurans cell configurations and a backsheet materials will be designed accordingly. This may be notably helpful in rising PV purposes comparable to vehicle-integrated PV. The Endurans are working with Lightyear, a startup, on the aborted growth of the Lightyear 0 photo voltaic car.
Whereas the Lightyear group failed of their try and deliver a high-end electrical car to market, “they’re making good progress, particularly on the photo voltaic aspect,” Theunissen mentioned. The modules Lightyear developed are curved, matching the automotive’s aerodynamics and aesthetics. In an try and pack such a big energetic photovoltaic space in a restricted house, says Theunissen, “the cells don’t align in a matrix association however in a non-linear manner that easily follows the form of the automotive.”
Lightyear makes use of interdigitated again contact (IBC) cells in its design, as a substitute of MWT, however each are served by a conductive backsheet. The fabric comes with a better value profile, as Endurans acknowledges, however that is compensated by elevated worth creation, the corporate argues.
“For module producers, now we have a transparent indication that the enterprise case shall be extra enticing than commonplace modules,” Theunissen mentioned. “There’s a increased value concerned however the worth shall be increased ultimately market.” The Endurans director added that efforts proceed to scale back materials prices, together with changing the copper backsheet with aluminum.
Regardless of the promise of opening up a wider vary of PV surfaces by way of new module codecs and back-contact know-how, the house stays a distinct segment. “The rationale photo voltaic is so good is that it is a standardized product that has an excellent lifespan, if put in correctly,” mentioned Jenny Chase, the Swiss-based head of photo voltaic perception at BloombergNEF, a enterprise information firm. “That is what is going to make the most important contribution to tackling local weather change.”
Chase acknowledges, nevertheless, that vehicle-integrated PV can present a “psychological profit, particularly if it is light-weight. Understanding that photo voltaic will trickle down the cost once I store may give me peace of thoughts.”
Of the purposes that may be addressed by versatile, light-weight photo voltaic, he means that the photo voltaic balcony could signify “one of the best of them, as a result of there’s some participation in that.” The benefit of set up additionally gives worth to the business, he mentioned. “There’s a bottleneck in Europe, to work on the set up.”
For Sunport, the truth that S-Flex will be put in on roofs that use sheet steel, with out drilling holes within the roof, is a plus. “This product may be very appropriate for factories with steel roofs,” mentioned advertising director Xu. “When you use our versatile module, you’ll be able to instantly use the glue and put it on. You needn’t drill holes within the roof the place water can get in.”
There are additionally financial savings when it comes to steadiness of system (BOS) elements and labor, Xu mentioned, which offsets the upper panel worth – itself a perform of the module’s increased materials value. “When you see the entire value of BOS – together with mounting methods – with customized modules, and together with human assets for set up, then the fee is comparable. We solely use glue , so the general BOS is decrease.
There is no such thing as a doubt that the again contact know-how, in varied codecs, is on the map of many module makers – together with the massive producers. Sunport itself plans to launch the following era of its know-how on the SNEC commerce present in Shanghai final month.
“It is a totally different back-contact know-how,” Xu mentioned. “The know-how is acquainted to us as a result of it’s a again contact. The floor has no holes, no ribbons, so the aesthetic is superb.
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