Day 2: High Efficiency Solar Technologies

Solar PV Industry Gearing Up For Microcrystalline Silicon Heterojunction Technology; Coordinated Effort From All Needed To Lower Costs

Day 2: High Efficiency Solar Technologies

TaiyangNews Head of Technology Shravan Chunduri moderated the executive panel discussion on Day 2 of the TaiyangNews High Efficiency Solar event, which had HuaSun’s Wenjing Wang, Risen Energy’s Po-Chuan Yang, Ideal Energy’s Dr. Liang Ouyang, and DKEM’s Kevin Nan talking about the future prospects of HJT. (Photo Credit: TaiyangNews)

  • TaiyangNews High Efficiency Solar Technologies Conference had day 2 discussion on HJT solar technology
  • It seems to be moving towards microcrystalline silicon from amorphous silicon at present which will further increase its efficiency
  • Costs can come down once all, including equipment makers and module makers, make a concerted effort
  • Industry has a clever roadmap to boost efficiency as well as production capacity over the next few years

Day 2 of TaiyangNews High Efficiency Solar Technologies Conference was dedicated toheterojunction (HJT) technology that has caught the fancy of cell and module makers due to less production steps it requires while producing higher output than Passivated Emitter and Rear Cell (PERC) technology.

Head of R&D Department at the German research center Forschungzentrum Julich, Dr. Kaining Ding shared what’s new in silicon HJT while sharing his learnings from recent workshops on the subject. According to Ding, one reason for the growing popularity of HJT is the maturity of equipment suppliers which is sure to bring down costs for this technology in the near future.

Even as the industry grapples with the challenge of current density for HJT, Ding believes on the whole the industry has a ‘clever roadmap’ to scale up HJT, creating a momentum to encourage more material and equipment suppliers to get into this space.

Delving further into the discussion, JA Solar’s Cell Technical Director Sean Jiang revealed the leading vertically integrated module maker is in the process of installing a 270 MW pilot line for HJT production. In the future, precisely in 2023 it plans to get into IBC and then tandem cells in 2024 as per the cell and module maker’s cell roadmap. Jiang also deliberated on a comparison study of edge losses and peripheral losses, which indicates that the edge losses can be lowered than the peripheral losses with optimized cutting methods.

Present in the HJT space since 2019, is another Top 10 module maker – Risen Energy. The General Manager of the HJT business unit of Risen, Po-Chuan Yang believes HJT will be the mainstream cell technology in 2024. The reason is final energy cost – currently the LCOE of the company’s HJT solution is already comparable with PERC, he said. He added that HJT with amorphous silicon (a-Si:H) double side passivation leads to super low surface recombination velocity (SRV) which benefits 100µm thin wafers, and a 100µm N-type mono wafer is cheaper than 160µm P-type wafer. Hence, thinner is better.

Discussing heterojunction solar cell technology, pure HJT cell/module manufacturer HuaSun’s CTO Wenjing Wang spoke about benefits of splitting the deposition of single layer in different chambers and also delved into microcrystalline silicon for HJT application, instead of a-Si:H. He also shared that in 2022, HuaSun will introduce microcrystalline silicon (Si:H) HJT with 2 GW annual capacity.

A leading Chinese company in the solar supply chain, PECVD equipment supplier for HJT technology is Ideal Energy and its Vice President Dr. Liang Ouyang said the company counts 12 cell and module makers for its equipment and the list is growing, demonstrating increasing appetite for HJT.

Encapsulant supplier Hangzhou First’s R&D Engineer Steven Tang discussed the selection of proper encapsulant materials for high efficiency N-type solar cells suggesting POE/EPE+EVA as being helpful from cost point of view for glass glass modules. According to Tang, both TOPCon and HJT are likely to end up owing 30% market share in 2025 with more than 50 GW of combined production capacity.

Metallization expert DK Electronic Materials’ (DKEM) Vice President of Technology and Marketing Kevin Nan listed critical challenges and opportunities from materials to process for HJT solar cells, while reflecting on recent progress on industry-ready and low-cost metallization solutions. According to Nan, fine line printing with SMBB and pattern design will accelerate laydown saving but maintain robust efficiency and reliability for HJT solar cells. Currently, silver paste screen printing still dominates PV metallization.

He had a suggestion to make that if the solar PV industry wants to reduce metallization cost for HJT, there has to be a coordinated and systematic effort including from equipment makers as well as from module makers. Nan also gave a brief overview on metallization paste made of copper particles coated with silver and emphasized that reliability is the key area of improvement.

Executive Panel

Moderated by TaiyangNews Head of Technology Shravan Chunduri, the executive panel gazed into a crystal ball to see where the world of HJT is headed in the future. HuaSun’s Wenjing Wang said mass production average efficiency of HJT is currently around 24.4% to 24.5% with potential to increase to 24.7% or may be hit 25% over the next 2 years. This will happen as the result of optimization expected all along the supply and value chain with a-Si layers, while microcrystalline silicon would give the next boost to reach 25.5% as mid-term increment.

Risen Energy’s Po-Chuan Yang considers HJT better than PERC due to its lower carbon footprint as it involves lesser number of production steps. Answering Chunduri’s query about HJT moving towards larger wafer sizes, DKEM’s Kevin Nan pointed out that this technology is more friendly to thinner wafers from metallization point of view.

As an equipment supplier, Ideal Energy’s Dr. Liang Ouyang said though the industry is ready for microcrystalline silicon HJT solar cells, it still needs to reach high efficiency for which further process conditions need to be created.

The panelists more or less agreed that HJT solar production capacity is to grow by an additional and minimum 10 GW by the end of 2022 as existing players expand and new entrants bring in new capacity.

The third and last day of TaiyangNews’ High Efficiency Solar Technologies Conference will take place on December 16, 2021 when the focus will be on TOPCon. Registrations to the event can be done for free here.

Day 1 of the conference was dedicated to PERC where the world’s leading module manufacturers LONGi and Trina Solar presented their latest product developments while new Turkish wafer-to-module maker Kaylon’s CTO Peter Fath emphasized that the world needs to reduce its dependence on fully vertically integrated module manufacturing in China by establishing local supply chains to diversify, improve sustainability, and if planned in the right scale and location also produce at competitive cost for PERC (see Day 1: High Efficiency Solar Technologies).

About The Author

Anu Bhambhani

Anu Bhambhani is the Senior News Editor of TaiyangNews

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