At Nanosolar, we have concentrated seven years and several hundred million dollars on one goal of an all-out engineering effort: to completely reinvent the design and manufacturing of photovoltaics and realize the blueprint of the ultimate solar electricity cell and panel. To that end, we have persistently pursued innovation and refused to accept the limitations of existing approaches and practices.
We hope the following information provides some helpful insight into why we are excited about what's happening in our laboratories and factories and offer a preview into how new solar technology will impact the trillion-dollar energy market. (Check back for updates to this page and/or subscribe to our news blog.)
Inside Nanosolar
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Printing Solar Cells
The holy grail of solar cost and capital efficiency has long been unlocking the key to how one could deposit a thin film of a semiconductor—100x thinner than a silicon wafer—using a printing process—100x faster than conventional high-vacuum deposition—and create an efficient, durable solar cell.
Our team has accomplished this by leveraging recent advances in nanoscience and by creating novel forms of nanoparticles dispersed into our proprietary ink formulation.
The result is that we can now apply equipment from the printing industry to produce solar-electric foil at very high speeds, bringing the economics of printing to the world of semiconductor manufacturing.
Assembling Panels
Our process and tooling innovations span almost every step in the production of solar cells and panels, including far faster assembly of solar panels.
Applying the latest in robotics—primarily from the automotive industry—and even reinventing lamination tooling enables us to assemble cells into panels with high throughput and the highest quality.
Our panel-assembly factory is automated to produce panels at the unprecedented rate of one solar panel every 10 seconds (640MW per year)—on a single line of production.
An Entire Technology Platform
The cell technology platform we have developed is characterized technically by a CIGS semiconductor printed on low-cost conductive metal foil and back-contacted through a Metal-Wrap-Through architecture, all using materials deposition processes developed for continuous steady-state processing within a roll-to-roll manufacturing framework. Based on the many further opportunities we see, it is clear we have only begun to tap into the possibilities of this cell technology platform. (Join our team if you would like to be part of this.)
On a product level, our solar cells are light-weight, bendable, easily interconnected, easily adjusted in size, and capable of supporting up to 25 Amps of current per cell (or up to 25x more than possible with other thin-film technology available today). These are each attributes that lend themselves to creating products with unique advantages and benefits and delivering application-specific customer value.
While cells can be of any size, our standard size is 165x135mm (a size in fact optimized from a system-installation perspective):
We create solar cell units independently from solar panel units. This allows us to drive innovation for each in parallel and rapidly respond to new market and product requirements, introducing new products without rendering obsolete the substantial investment that cell production requires one way or another.
Nanosolar Production Process: Step by Step
Each of our production steps is geared towards achieving high intrinsic throughput so that we can produce solar cells and panels with distinctly superior cost and capital efficiency:
| 1. Semiconductor Nanoparticles. Because the targeted film is micron-thin, the nanoparticles that create it are even smaller. Nanoparticles shown to the right are 20nm in size, equivalent to 200 atoms in diameter. We have developed a proprietary formula for which kinds of nanoparticles produce the best solar cells, developed high-yield proprietary techniques for fabricating exactly these kinds of nanoparticles. 2. Nanoparticle Ink. The ink we have developed is based on proprietary chemistry suitable to disperse our nanoparticles into a high-quality dispersion which is stable and non-agglomerating and produces high-quality coatings. |  |
| 3. Printed Foil. The nanoparticle ink is coated onto a specially-prepared proprietary alloy of metal foil using high-throughput coating/printing techniques that work in normal atmosphere, with no cleanroom required. 4. Cell Formation. The cell is completed by adding fingers and a back contact capable of efficiently carrying current with minimal optical and resistive loss. The solar-electric foil is then slit and sheeted into pieces to form individual cells. Cells can be cut to any size. Cells are individually tested and sorted into performance bins based on electrically matched characteristics. |  |
| 5. Panel Assembly. Cells are assembled into circuits and laminated into panels. By using cells only from matched performance bins, mismatch losses within a panel are minimized to less than 0.1%, improving performance and reliability. Our solar panel assembly factory is automated to produce one solar panel every ten seconds on one line of production. |  |
In reality, there's quite a bit more to it of course. In fact, our solar cell are comprised of more than fifteen materials layers/components, several of which are only a few hundred atoms thick.
Medium Efficiency at Ultra-Low Cost + Smart Product Design = Optimum Customer Value
By delivering medium-efficiency solar cells at ultra-low cost, the optimum in cost efficiency and affordability is achieved for solar cells and panels. That's because the difference between an energy-conversion performance of 15% versus 20% is not even a factor of two while the difference between $20 and $200 in cost per square meter is a factor of ten. It's the solar power equivalent of trying to build a Toyota versus a Ferrari.
That said, even though we have always primarily focused on ultra-low cost, our ultra-low cost approach is actually now also starting to deliver some quite respectable efficiencies—better than our own scientists considered feasible not too long ago. Solar foil efficiencies as high as 16.4% have been independently verified by the National Renewable Energy Laboratory (NREL); and our first-generation production is capable of delivering 11% panels. (See our Cell Technology White Paper below for details.)
Then smart product design plays an instrumental role in ensuring that our customers do not get penalized at the total-system level for not using panels with the very highest efficiency possible. Conventional wisdom in solar asserted that relatively lower efficiency results in relatively higher cost of the balance of a system and its installation. But this discounted the influence that smart product design can have that's based on a careful understanding of the various component cost drivers in best-practice installations. Smart product design can completely eliminate any balance-of-system cost penalty.
 | Ultra-Low Cost Solar Cells: An Overview of Nanosolar's Cell Technology Platform (in pdf format) Nanosolar White Paper, September 2009 |
 | The Nanosolar Utility Panel™: An Overview of the Technology (in pdf format) Nanosolar White Paper, September 2009 |
 | Data Sheet, Nanosolar Utility Panel™ (in pdf format) |
Technical/Industry Publications
Nanotechnology to the rescue of capital efficiency (in pdf format), Perspective in Photon Magazine
High-performance thin-film photovoltaics using low-cost processing (in pdf format), International PVSEC 2005 conference
Our Factories
Our cell manufacturing facility in San Jose, California:
Our European panel assembly factory near Berlin, Germany:
A Rapid Thermal Processing (RTP) tool in Nanosolar's cell manufacturing facility:
Patents
We have over 300 patents issued, licensed, or pending regarding all critical aspects of our technology, including a host of foundational patents as well as the patents with the earliest filing dates on printed CIGS. Still, we find that the vast majority of our intellectual property is held in the form of scientific and engineering trade secrets.
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