Under the hood: Sunpreme's 500W module

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Solar 2.0 is a term that can be overused and undefined. For fledgling U.S./Chinese manufacturer Sunpreme, it means an ultra high efficiency product, at competitive prices. Since its first series production in 2011, it has pushed efficiencies of its mono c-Si/a-Si hybrid cell technology from 15% to 22%, on a module level, in three years. This is based on frontside “hero” efficiencies, although the company produces bifacial, glass-glass modules and it claims average production efficiencies of well over 19% on the frontside.

The founders of the Sunnyvale, California, based company hail from Bell Labs and Applied Materials’ LCD branch. It is a re-purposing of LCD technology that allows for the a-Si deposition and doping on both sides of a mono-cSi cell. Frank Pham, Sunpreme’s chief engineering officer and COO, spoke to pv magazine about what is behind its high efficiency strategy.

Why did you make a 500 W module, using 96 cells, your goal?

This was designed specifically to produce a panel that can help lower LCOE through lowering the BoS costs for PV. Having a panel of this magnitude of power using high efficiency cells, that it would help the industry to lower BoS costs.

Can you actually roll out such a module onto the market and how long would that take you?

Right now as you can see we have full tested the module and we are planning full production release in the middle of next year. Right now we are looking at building customer acceptance for the new form factor.

And what about your 60 cell modules?

We have released the 60 cell as of last week, and what we have done right now is that we have completed UL and IEC full certification and the first shipment of panels are coming home to the U.S. as we speak.

So what modules are you currently shipping to the U.S.?

All the modules destined for PV power plants that we are shipping currently are the 360 W, 72 cell configuration panels. It is a 360 W flashed frontside, and in a bifacial module has a performance of over 400 W.

Bifacial, glass-glass modules do appear to be very much a niche product. How do you respond to comments that this technology is not really destined for wider application?

I would simply say that we are shipping competitive product. We have 15 MW going into New Jersey, we are fully bankable with multiple banks. We have 6.4 MW of construction in Martha’s Vineyard. Our company is not a follower, we are front and center.

But what about on cost? Surely a high efficiency module like yours is high cost?

We are a very cost conscious company. And cost in many ways is defined by end of the line BoS costs and we design for that. I would describe our technology as second generation solar, or Solar 2.0 – super high efficiency but still low enough cost that it can compete on the MW power plant scale.

On a technology front, why are you able to achieve these high efficiencies?

Our cells are very symmetric, using HCT platform (hybrid cell technology) – basically we have amorphous silicon deposited on silicon wafers. We have an intrinsic amorphous layer, we also have the dopant layer both p and n-type [n-type top, p-type bottom].

And these are proprietary processes?

Absolutely, we have patents to cover our processes.

So you have developed a process to be able to dope the cell on both sides simultaneously?

That’s right, we can do that on the existing equipment set that we have.

And is that more or less standard equipment?

Our company vision from the outset is, since we came from the equipment industry, that we would not develop equipment. Instead we focus on using existing TFT LCD [thin-film-transistor liquid-crystal display] equipment and what we want to do is be one or two generations behind the leading edge.

For example LCD is equipment now is in gen10. We use gen6, so our CapEx can be kept at the lowest possible level. Our CapEx is only ten cents on the dollar. We have taken over an existing factory, and use a gen6 product line to deposit our amorphous layer and out anti-reflective coating layer.

You do use mono crystalline wafers, but I have heard that there may be somewhat of a mono wafer squeeze on at the moment and that it is difficult to get good quality mono wafers. Is that your experience?

We have developed a very good strategic partnership in China with our number one supplier and rest assured, the demand of our current 40 MW line now will be met and our future 100 MW line, that will be ramped by the middle of 2015, will also be met. As of June 2015 our fab will be fully converted to 100 MW.