"N-type solar cells" began to be mass produced in earnest. They use "N-type silicon" (a semiconductor whose electrical charges are carried by free electrons) as the substrate of solar cells (power generation elements) instead of the conventional "P-type silicon" (a semiconductor whose electrical charges are carried by positive holes).
We interviewed Liu Yong, senior vice president of Jolywood (Taizhou) Solar Technology of China, which has been promoting the sale of N-type solar cells, and asked about the company's product strategy as well as the advantages and potential of N-type solar cells.
Increasing annual production volume of N-type to 2.4GW
Q: Could you tell me about Jolywood Solar's N-type module (solar panel) mass production plan?
Liu: The production capacity as of the end of 2017 was approximately 1.2GW. We plan to double the capacity to 2.4GW, the highest class production scale of N-type in the world, within 2018. The shipment-based capacity will reach 1.5GW this year.
The shipment volume intended for Japan was approximately 20MW last year, and we estimate that the volume will exceed 100MW this year.
Q: What are the advantages of adopting N-type technologies?
Liu: N-type technologies are called "crown" technologies for single crystalline silicon solar cells. For example, the "HIT" (Heterojunction with Intrinsic Thin-layer) products of Panasonic Corp and the Back Contact (IBC: Interdigitated Back Contact) products of SunPower Corp of the US, which are advanced solar cell modules with top-class conversion efficiencies, are N-type. Nearly all products with 22% or higher conversion efficiency incorporate N-type solar cells.
New models introduced by Jolywood Solar feature 21% or higher conversion efficiency, and the output of a type with 60 single crystalline silicon cells per sheet is 300 to 315W.
Q: The production process is complicated and the cost is high, which are issues facing N-type modules. The HIT and IBC products have yet to overcome these issues and are mainly used in places where the high sale prices are acceptable, such as rooftops where installation space is limited.
Liu: According to our analysis, the cost competitiveness of the N-type technologies has not yet been enhanced because of three major reasons. The first is the fact that the manufacturers use expensive semiconductor production equipment intended for production of information devices in many cases and the equipment exceeds the required performance.
The second is the failure to make the most of the technologies. Double-sided power generation is possible for N-type cells, but product strategies for taking advantage of the feature have not been fully promoted. The third is the immature supply chain of materials that support mass production of N-type modules.