FAQ

Q: Can you use glass substrates instead of stainless steel?

A: We started our development on glass substrates, but we soon came to the conclusion that stainless steel is a better choice. These substrates are; cost effective, more durable, more suitable for rapid thermal cycles in manufacturing, thin enough to be laminated in a module and act as a conductive back contact.

Q: Your cells are not square, why? How much efficiency do you lose when going from cell to module?

A: We use circular sputtering targets when we deposit the material on the substrates. To get the best material yield the cells should ideally be circular. We can make them perfectly square, but in doing so, a lot of the deposited material would end up on the shields instead of on the cell, resulting in a higher cost per Wp. The semi square 6” cells are an optimized compromise between module area loss and cost per W for the cells. You have the same situation with mono crystalline silicon cells that are sliced from a cylindrical ingot.

We lose about 10 % on the area when going from cell to module. However, we do not put an anti-reflective coating on our cells and when laminated behind glass we reduce the reflection and we get a higher current. The total efficiency loss when going from cell to module is less than 10%.

Q: Can I use my existing module manufacturing line with your cells?

A: In general yes, sometimes with some minor modifications.

Q: What is the highest capacity line you can deliver?

A: With the Midsummer concept you add several identical machines to build production capacity. There is no upper limit.

Q: We want to start up production with your line. Are you interested in Joint Venture with us?

A: We have a policy decision not to enter into JVs with customers. That would make us a competitor to new potential customers.

Q: We have heard that Indium is rare. Do you have any plans to replace it?

A: There is plenty of Indium in the earth’s crust, actually 3 times more than silver. There is also a lot of Indium being recycled from electronic products. We don’t see the availability of Indium as a problem.

Q: Silicon wafers and cells have become much cheaper lately, can you really compete with this technology?

A: The production cost of Midsummer’s solar cells is still lower than silicon solar cells. The thickness of the deposited material is only a few thousands of a mm and the material utilization is very high.

Q: Can I see the Duo line in operation somewhere?

A: You are most welcome to visit us in Stockholm, Sweden to see the line running and producing CIGS solar cells at an amazing pace!

Q: Do I have to buy all the production materials (substrates, sputter targets and process gases) from Midsummer?

A: We normally do not sell the production material, but we will provide you with a list of our certified suppliers, so that you can source all the production material directly to your factory without costly middle men.

Q: What about module manufacturing, do you have products for that as well?

A: We don’t sell equipment for module manufacturing, but we will be happy to put you in contact with suppliers that have experience working with our type of solar cells.