Photovoltaics - manufacturing capacity reaches 1000GW?
Photovoltaics are growing at breakneck pace. and that is important for printed electronics. According to the IEA, in 2022, global PV manufacturing capacity increased by more than 70% to nearly 450 GW, with China accounting for more than 95% of new additions across the supply chain. The growth continued at an unabashed pace, with the IEA expecting the global manufacturing capacity in 2024 to reach an incredible 1000 GW.
Source: click here
Screen printing silver pastes has a near complete market share for metallising silicon photovoltaics. The amount of silver per cell - and consequently per watt - for front and rear metallization has declined. In 2023, it stood for PERC photovoltaics (the dominant technology) at around 10 tonnes per GW. Given the expected manufacturing capacity in 2024, this could translate to around 10,000 tonnes of silver (and more of paste depending on loading etc) per year!
This is also an incredibly advanced printing technology. This field can already execute ultra fine line printing at scale. In 2022, the linewidth of the printed fingers were around 30 um with ca. 10um alignment precision as standard in manufacturing. This is projected to be further narrowed, reaching a linewidth of 15um with 5um alignment precision in 2032 to reduce the amount of expensive silver per cell. In R&D and pilot settings, such screen printed linewidths are already being demonstrated with printed bus bars exhibiting incredible aspect ratios. To illustrate the progress, note that the state-of-the-art publications just a decade ago were reporting linewidths at 80-100 um!
What is more incredible is that to maintain the high production speeds, these ultrafine lines are printed at incredible speed. Indeed, the screen printing system in 2022/2023 could achieve >7500 wafers per hour (M10 wafers: 182x182 mm2). The industry roadmap sees this increasing to over 10000 wafers per hour (with 15um linewidths!).
These numbers are incredible technical and manufacturing achievements, and are a testimony to the inexhaustible innovation power of the screen printing ecosystem - from mesh and screen manufacturing to material and machine developers - to cooperate and push the performance to new heights.
Source here.
New silicon photovoltaics beyond PERC
The manufacturing of newer silicon photovoltaic architectures like TOPCon or Heterojunction cells is also ramping it up. Their market share is still small, but in a vast market. Interestingly, these new photovoltaics bring with them new requirements, translating to new innovation opportunities.
For example, for heterojunction cells, the presence of the hydrogenated amorphous silicon imposes a temperature limit on the firing temperature (<250C), thus epoxy based pastes instead of firing type must be used. These pastes have, however, higher volume resistivity (ca. 6 uOhm.cm vs 2-3 uOhm.cm for PERC PVs), longer drying and curing times (>30min vs <2min), slower printing speeds (<250 mm/s vs > 400mm/s), worst aspect ratio and fineline printing capability (50-55/10-22 um/um vs <30/10-20um), poor solderability, and much higher consumption per cell to reach same conductivity (30mg/W vs 10mg/W), and so on. Addressing these technical limitations is in fact an innovation frontier for paste makers and printers worldwide.
Going beyond silicon photovoltaics
Many photovoltaic technologies are in development, seeking to complement and/or replace silicon in specific fields. Two prominent options are organics and perovskites. For both, printing is likely to the main method of manufacturing the cells and not just metallization
The former has a much longer development history with several cycles of high hope followed by deep disillusionment. The latter holds extremely high promise, both as a standalone and tandem technology, provided manufacturing and stability issues can be addressed. Both technologies offer newcomers and new territories ways to break into the vast solar market dominated by China.
For organics, currently automated R2R printing is being scaled up, especially in Europe, building up decades of accumulated expertise to simultaneously establish a high-throughput process as well as a roadmap of niche markets that may, after over two decades of development, allow this technology to become commercially competitive.
For perovskites, printing will likely play a pivotal role as perovskite active layers can come in ink format and be solution processed. Indeed, many around the world are today establishing hybrid printing lines to manufacture perovskites. Hybrid here means that not all layers will be printed, but the production will include R2R printing and other vacuum processes.
There are many innovation and development opportunities here. Stable and highly efficient inks with friendly solvents and rapid curing properties are required, and high-speed printing as well as vacuum and laser processes are required to print cells at scale. At the same time, fundamental challenges - in particular around the issue of long-term stability - must be addressed. Luckily the worldwide momentum here is strong and the market pull even stronger, increasing the chance of ultimate success.
To appreciate the growing successes and the wonderful diversity of this industry, we invite you to join the TechBlick Future of Electronics RESHAPED events in Boston ( 12 & 13 June 2024) and/or Berlin (23 & 24 OCT 2024) where the entire global industry learns and connects. More info on www.TechBlick.com
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