From pv journal 03/23
The brand new 400 W-plus shingled photo voltaic modules are available on the market, serving the necessity for high-powered, extra sturdy, glossy all-black merchandise. The Chinese language cell large Tongwei is accountable for new modules – its Terra collection launched in 2022. The Terra collection is out there in energy courses of 400 W to 430 W, with efficiencies from from 20.1% to 21.7%.
Tongwei is famend as a significant provider in China that adopts shingling, which entails slicing photo voltaic cells into strips which might be then joined collectively by electrically conductive adhesive (ECA), barely overlapping alongside the size of the cell. edge.
The pinnacle of Tongwei’s shingled module division, Yan Li, stated that shingled merchandise provide “benefits in energy, effectivity, and reliability” and technical benefits as a consequence of “high-density packaging and versatile interconnection.”
“Nevertheless, we imagine that the vary of Terra high-efficiency shingled modules with an aesthetic look will goal sure markets, and enhance our share and model affect within the residential phase,” Li stated. . Together with lovely aesthetics and energy, shingling additionally supplies sturdiness, Li stated, as a consequence of “low threat of hot-spots, resistance to micro-cracks and distinctive mechanical load efficiency.”
Tongwei, which has 70 GW of annual cell capability – and plans to hit 130 GW to 150 GW by 2026 – stories that it has 6 GW of Terra traces, whereas module capability has reached 14 GW, together with collection of half-cuts.
IP claims
Whereas Tongwei’s adoption of shingling represents a significant technological advance in scale, the commercialization of shingling was years within the making. Silicon Valley-based Solaria Company, based in 2000, started promoting shingled PowerXT modules in 2016. Solaria claims to carry “greater than 250 issued and pending patents within the area,” which most of them, in all probability, associated to shingling.
The California firm vigorously defends what it considers mental property (IP). In June 2022, it settled a patent infringement case filed in 2020 towards Sino-Canadian producer Canadian Photo voltaic for allegedly infringing its shingling know-how.
Solaria desires to merge with installer Full Photo voltaic and float the ensuing Full Solaria enterprise as a vertically-integrated firm just like SunPower. Full Solaria can produce shingled PowerXT modules with an output of round 400 W underneath a “low capex [capital expenditure] mannequin,” with manufacturing “by producers in Thailand, Cambodia, Vietnam, and India.”
Secure IP
Tongwei stated it began module R&D in 2016 and hooked up significance to constructing an mental property system. “From the start of the shingled product venture, Tongwei has already began the format of the patent finish,” stated Li. “After seven years, Tongwei has fashioned an impartial shingled know-how map.”
George Touloupas, senior director of know-how and high quality at high quality assurance supplier Clear Power Associates (CEA), factors to Tongwei’s statements that the corporate has “its personal method of connecting,” with out IP considerations. Touloupas added, “The chief know-how officer of the shingled module is from SunEdison and he brings his shingling expertise from that firm to Tongwei.”
Trying underneath the hood, Touloupas discovered that the interconnection method utilized by Tongwei seems to have extra advantages. “Tongwei can also be investigating a special interconnection know-how the place the shingled cells comply with a jagged sample, which is extra steady in hot-spots and has much less loss as a consequence of shading.”
Matrix format
Researchers at Germany’s Fraunhofer ISE revealed take a look at outcomes from such a shingled-module cell format within the journal Progress in Photovoltaics in 2021. Within the paper, the researchers name the approach a “matrix format” during which the lower cell items are positioned in an offset sample, “half a cell lengthy” – with half-cut shingle cells positioned on the perimeters to lead to a regular rectangular module format.
“By shifting the photo voltaic cells from row to row at half a cell size, an extra parallel interconnection of all photo voltaic cells inside every row is achieved,” the researchers wrote. .
The Fraunhofer ISE workforce examined matrix shingled modules in varied shading situations, together with shading diagonally throughout the module, and located that the matrix design resulted in a major enhance in power yield. Electrical present can bypass shaded areas extra successfully as a result of offset cell format. The format additionally reduces the chance of mechanisms inflicting hotspots – the results of partial shading.
As splendid, unshaded areas for photo voltaic are more and more scarce, the Fraunhofer researchers concluded that the matrix format can be significantly invaluable. “Nice potential for solar energy technology meets a big number of irregular shading circumstances, which makes shading tolerance an important facet,” the teachers wrote.
Challenges stay
Advances in shingling know-how, and its adoption on a bigger scale, level to know-how probably shifting into a brand new period of improvement. Competitors from different applied sciences will stay fierce, nonetheless.
“4 or 5 years in the past, shingled modules had [a] 10% effectivity benefit in comparison with atypical – on the time – full-cell, four-busbar modules; that’s not the case,” stated CEA’s Touloupas. “With the introduction of half-cut cells, multi-busbar, paving, or tiling; this 10% module space effectivity benefit has been exhausted.”
As Tongwei and different shingling advocates argue, there are numerous benefits past effectivity. The usage of ECA over busbars, with lead, is one such benefit – including environmental credentials to the shingled technique, together with sturdiness, shading tolerance, and aesthetics. As with different high-efficiency applied sciences, the silver content material of ECA should proceed to lower with a purpose to use it sustainably in massive volumes (see field).
Low-silver ECA
ECA has a comparatively excessive silver content material – as much as 70% to 80% was famous by lecturers in industrial merchandise in 2019. That will change, nonetheless, due to conductive particles coated with silver and optimized particle shapes. “We in all probability began lowering silver consumption in our adhesives, perhaps 10 years in the past,” stated Wealthy Wells, chief know-how officer of Ohio-based, Japanese-owned Nagase Chemtex America. a producer with greater than 15 years of expertise in supplying photo voltaic corporations. . “Not too long ago, I’d say within the final 5 years, there have been some very good achievements.” Wells stated the progress in lowering the ECA’s silver content material set for photo voltaic got here by means of two key developments. The primary is to exchange pure silver particles with silver-coated alternate options. Copper on the core of the particles, says Wells, “is among the many choices on the market.” Nagase Chemtex labored with researchers from the Power Analysis Heart within the Netherlands to develop silver-coated particles for ECA. Ohio enterprise scientists are additionally making an attempt to optimize particle shapes. Longer, flatter particles present equal conductivity from a smaller quantity of conductive steel. “The fashions for percolation, to construct a conductive community by means of the system, present which you could create that community of conductivity at a low degree. [metal] loading if in case you have a better facet ratio,” stated Wells. Mark Francis, the gross sales and advertising and marketing supervisor of Nagase Chemtex, has a protracted historical past within the semiconductor trade. He stated, becoming a member of the corporate primarily to develop the photo voltaic enterprise, he was shocked to study that PV producers are utilizing lead solder for cell interconnection. “We’re seeing a push for silver discount within the cell grid and the interconnection,” Francis stated. I am considering, when are they going to show round and say we do not need to do cell interconnection on lead anymore?”
Tongwei stories that it’s working to optimize the bonding energy of ECA and its conductivity – which it calls the non-silver and silver methods, respectively. “We’re dedicated to bringing our environment friendly and eco-friendly Tongwei Terra collection to extra properties,” the corporate stated.
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