Patent awarded to C3 – is it the most impactful PV innovation since half-cut cells?

C3 Solar Inventions

What if you could purchase one of your favorite PERC solar panels, but with an added 2 or 3 Watts per panel and a 0.1 percent efficiency gain? Sounds cool, I’m sure. Well, how about on top of that it could also cost less to manufacture? This is the pitch of Solar Inventions’ Configurable Current Cells, or C3.

We originally featured this prototype cell process in our Winter 2021 issue [subscribe here for free], fresh off a first-place win in the U.S. Department of Energy’s American-Made Solar Prize competition. We’re writing about it again because the U.S. Patent and Trademark Office has awarded Solar Inventions a patent (U.S. Patent No. 11,145,774) for this new solar photovoltaic cells architecture.

Yes, the door is officially open for leading manufacturers to license and incorporate this new process, which Bill Nussey, CEO of Solar Inventions, says requires nothing more than a small change to the metalization print screens of any PV production line.

“Our global IP portfolio is coming together,” Nussey said. “This patent opens the door for us to move forward on joint ventures with key partners in areas with large-scale cell and module manufacturers, such as India, China, Southeast Asia, the EU, and the U.S. We’ve begun discussions with potential partners in all of these regions.”

More on that in a bit, but back to that cost reduction and performance boost …

Reducing silver is gold

C3 achieves its gains by creating multiple “lanes” or subcells on a single wafer by electrically dividing each cell during the metalization process. This mimics the benefits of half-cells – higher power – but without needing to break cells. The resulting gap allows more light in, hence the gains.

Crucially, that gap also means less silver is needed per busbar.

For 9-busbar HJT cells, C3 provides a 12 percent reduction of silver (5-10 reduction for PERC). That’s a cost savings of about 0.1 cents per Watt. Multiplying that by a 1 GW and you’re talking $1 million in savings at current silver prices. FYI, during the early months of the pandemic, silver spiked over $24 an ounce for the first time since 2013 and has continued to trade in that range. And let’s not forget the push for larger and larger cells and module formats. The C3 technology is appealing on those economic advantages alone.

Chief Technical Officer Ben Damiani recently presented two major papers on the technology to two international conferences (IEEE PVSC in the U.S. and EUPVSEC in Portugal). The first looks at boosting a solar module’s performance by using the C3 technology to increase the cell-to-module ratio. The other explains the science behind the silver savings.

In a way, this silver reduction – which is an enormous cost savings benefit – was just a byproduct of seeking loftier panel performance goals.

Disruptive technology

Considering the power gains and cost reductions as well as its current commercial viability, C3 has the potential to be the most disruptive solar panel innovation since half-cut cells. Unlike the half-cut cell innovation, no manufacturing line upgrades are needed. No laser cutters or cell testers or handling equipment.

Damiani is a veteran inventor in the solar and semiconductor sectors who previously worked at Suniva and Intel. This new technique effectively creates a new cell architecture, and Damiani made it clear in our chat that these early gains are just the beginning of his vision. His long-term goal with this new architecture is to remove the solar industry’s reliance on module-level electronics to mitigate shading performance losses and microcracking issues.

“It’s got a many-layered advantage,” he tells us. “Ultimately, the thing I was shooting for was … when I put a panel on a roof and the chimney shades part of it, I would like to just shut off the part that’s shadowed. So, I took the busbars and made each one become its own solar diode. The idea is that later on I’ll be able to turn those on and off as I choose to keep the overall panel producing.”

Preliminary results on that front already show a slower turn-on time from when shadowing occurs to when current reversal occurs, and it takes about a 5 or 8 percent shadowing mismatch instead of the typical 5 percent trigger point.

“There are more changes we can make on this to make the behavior stronger,” Damiani says. “The harder part is explaining how it works and getting people to recognize something different as being OK and better. That takes time.”

Testing and timeline

Solar Inventions has done a year of evaluation at NREL in Colorado. They have completed a full certification with CFV Labs for Canadian standards. They are finalizing pending C3 patents in China, Europe, India, Japan, Australia, South Korea, Mexico, Israel, United Arab Emirates, Egypt, Brazil, Saudi Arabia, Canada, Turkey, Vietnam, and Taiwan, which together account for 90% of the worldwide solar market.

And in 2022, they expect solar panels to roll off production lines with C3 cells. They couldn’t give us specifics just yet, but Nussey says they have “run pilots with companies that represent dozens of GWs of production. The rate of deployment on their lines will depend on how quickly and effectively they can put the C3 technology into their new lines.”

Gregg Freishtat, Chief Commercial Officer, added, “We expect these partnerships to develop a stream of new inventions and IP that will be co-owned with our partners and marketed in those regions and worldwide by Solar Inventions. We expect our joint venture partners will share in a substantial portion of all licensing revenue in their region.”

If you’re too impatient to wait for those official announcements – and you want an actual answer to the headline of this article – well, you can always request C3 from your supplier.

“If there’s a strong customer who wants 200 MW of it, it just has to be certified,” Damiani clarifies. “So, to drop in our tech on top of that, it should only take a 3-week post certification test because we’re only changing a small part. Then it’s one or two days later after changing optical equipment and calibrating them.”

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