From Suntech to Sunman’s glass free modules

Rooftop solar installation in Germany


What did you do after leaving Suntech, and how did this lead to your role at Sunman?

Zhengrong Shi: We had a really great time at Suntech. After over 10 years of intensive non-stop working, I took about six months off. I lost a lot of weight – around 10 kg. But my passion for solar never went away. I have always dreamt of powering our globe with 100% renewable energy. At Suntech, we achieved a lot, and now we see that PV has become very cheap. I'm very proud that we contributed to this industry. But there are still many other things that we have to do, for example in the field of energy storage and energy management. Therefore, I wanted to work again. But first I had to gain back my personal independence. Before 2013, I relied on my secretary and staff to do everything, so it was an adjustment. Once I was on my feet again, however, I continued my work in innovation, helping young people in the new material and renewable energy sectors. So far, we have helped some of them to commercialize some technology.

Zhengrong Shi at the Sunman booth during Intersolar Europe 2019.

Image: pv magazine

Were you able to financially support yourself with finances from your founding of Suntech?

We have always had some financial support, together with other investors. Sunman is one company I try to show my support for, for instance. I really believe the product has a future role in expanding the application scenarios of PV. When cost is not a major issue, people will find new ways of applying solar to their lives. That's why Sunman developed this glass-free lightweight polymer material solar panel, which weighs just 2.5 kilograms per square meter. The two covers – about one millimeter thick – can basically be applied to any surface. I call it a solar skin. We can produce the panel tailor-made, to fit any size or any shape.

There have been other trials to produce polymer modules before. What was the main challenge you had to overcome with Sunman?

There were a lot of similar innovations in the product design in the past. We saw that many years ago at Intersolar. But to make a product commercially applicable, with a customer willing to buy it, you have to deal with some parameters. I call it the boundary conditions. Because we are in the energy industry, products we invent have to be durable and safe. It is also important that they are affordable. We saw many similar products in the past, but they were several times more expensive than glass-based panels. There could be some niche applications, but most customers could not afford it.

What was the key innovation from Sunman to fulfill all these requirements?

First of all, we still use crystalline silicon solar cells, because this technology has been proven in terms of efficiency, reliability and cost. So basically, we leverage all the advantages of the crystalline silicon solar cell technology. Secondly, we developed the polymer materials, because there is a huge polymer industry. There are so many recipes available to choose from. People may choose the easiest one, which meets the technological criteria, but which fails on cost. Therefore, we spent a lot of time conducting research; pulling industry partners to very broadly try new and different recipes; to pass necessary tests according standards and regulations; and to carry out a lot of internal durability tests. We spent millions of dollars doing that in the last few years. I'm very glad that we have now found several recipes for polymers that meet the necessary criteria.

Have you developed your own patents?

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Yes, we have filed over 20 patents. Some are still pending and some have been approved.

How many people work at Sunman, and who are the investors?

At the moment, 80 people are working on material development, product lamination and production. We have some international and Chinese VC investors; and we’re going to continue raising more capital to expand growth.

What are your targets for the next years?

We will provide opportunities for customers to get know us and our product better. We hope to sell hundreds of megawatts.

Can you already produce so much capacity?

Yes, we have a capacity of 100 MW.

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