Pushing PERC Cells To Its Limits TaiyangNews Conference

• TaiyangNews PERC solar cell virtual conference had participation from leading equipment suppliers
• Common consensus is that PERC will stay in the game for some more time as it enjoys low-cost advantage over other newcomers
• With smart manufacturing and an integrated effort from all PV industry segments, there is potential for PERC to further bring down costs
• TaiyangNews also shared an overview of our upcoming PERC Cell Production Equipment Market Survey during the event

As the most widely used solar cell technology in the world today, passivated emitter rear cell (PERC) remains the industry's workhorse today, as goes the cliché even as it faces increasing competition from emerging technologies as TOPCon and heterojunction (HJT). However, as TaiyangNews Managing Director Michael Schmela pointed out, while the efficiency level of PERC cell peaks, there are a number of efforts being made production wise to further lower its costs to keep it attractive as manufacturers continue to invest in expanding PERC solar cell capacities.

The March 22, 2022 Virtual Conference on Pushing PERC Cells To Its Limits organized by TaiyangNews designed to discuss how to manufacture highest efficiency standard solar cells. The conference brought together leading stakeholders from research, cell production equipment and materials supply to discuss ways to improve the performance of PERC cells and reduce costs.

ISC Konstanz Project Manager-Technology Transfer, Dr. Joris Libal pointed out that PERC stepped in the PV technology space, taking over from aluminum BSF technology that reached its highest efficiency limit of 20%. Currently, average efficiency of PERC cell in mass production ranges between 22.5% to 23.0%. He did caution to read the fine print before taking PERC cell efficiency announcements at face value, as some of the cells actually include features of more advanced cell technologies.

Libal believes that even if PERC cell technology reaches its efficiency limit at around 23.3%, efforts continue towards cost-reduction via higher throughput, reduction of silver paste consumption, with the help of industry 4.0. Moving on, the next evolutionary step after PERC is passivated contacts on the rear side meaning TOPCon, as per Libal.

SVP Technology & Innovation, Holger Kühnlein of wet chemical process equipment supplier from Germany, Rena Technologies GmbH, was of the view that while PERC is increasingly threatened by the advent of TOPCon, and possibly HJT in the future, both these newer technologies will consume more silver per W, compared to PERC. To beat PERC, TOPCon will need to see its efficiency limits reaching closer to 25%, while keeping costs down.

As for PERC, Kühnlein expects further cost reduction by working on lowering metallization costs.

Discussing application of cost-effective doping solutions in PERC solar cells, Overseas Sales Director Jiang Shuai of Chinese equipment supplier Naura provide details about benefits of low-pressure diffusion for solar cell technologies. Even as the company caters to PERC cell technology, Shuai said it already has tools for TOPCon customers that shows the growing popularity of this emerging technology.

Providing an update on deposition equipment for production of high efficiency PERC cells, Ideal Deposition's Sales VP Zhang Dan said for any cell technology to work efficiently in mass production, it is critical to be without wrap-around which is where atomic layer deposition (ALD) comes in. According to Dan, P-type PERC solar cell faces efficiency a bottleneck at topside metallization because of limited bulk lifetime. He added that the topside emitter passivation of N-type TOPCon solar cell has more critical requirement for the film growth and passivation.

Continuing with ALD, another leading Chinese PV equipment maker's representative, Leadmicro's CTO Dr Wei-Min Li stressed smart ALD enabled PERC replacing PECVD as a mainstream technology for passivation of high efficiency solar cells since it practically eliminates wrap-around, shows better anti-LeTID property, hence better efficiency. Li also said his company recently sold a 2 GW turnkey TOPCon line to Suntech.

Silver paste supplier to the PV industry, Fusion Technology Director Jian Bao hailed PERC for having the low-cost advantage over TOPCon and HJT technologies. Going forward, he sees narrower line printing paste as the key indicator for mono PERC cell costs coming down in mass production. Bringing down finger width will also be helpful in addressing new challenges related to paste development, firing process and screen technology.

Executive Fire Chat

In a fire chat with Shravan Chunduri of TaiyangNews, Dr Wei-Min Li from Leadmicro admitted that there may be scope for PERC cell technology to sustain in the future but it would all depend on market demand. If there is some, it will require integrated efforts right from smart manufacturing practices to transportation to bring down the costs for PERC.

Giving a glimpse into the future of PV cell technology in the next decade, Li said his company is currently researching on tandem cell devices which it sees as growing its clout in the coming years.

TaiyangNews Market Survey

The conference was also the launch event of TaiyangNews PERC Cell Production Equipment Market Survey 2022 Edition summarizing the developments associated with production tools used for PERC, covering 5 important stations namely surface preparation, emitter formation, passivation, metallization and testing. Presenting an overview of the survey, TaiyangNews Head of Technology Shravan Chunduri shared a common trend across the board which he specified as processing larger wafers, higher productivity, improved process effectiveness (quality) and reducing costs. The report will be available for free download on our website end of March. Stay tuned!