PV technology route dispute has always been a hot topic. Recently, LONGi suddenly took a stand on BC batteries, causing a new wave of discussion on technology routes in the industry.
LONGi announced that it will totally bet on BC batteries. LONGi Solar believes that BC batteries will gradually replace TOPCon as the mainstream of the industry. However, enterprises in the same industry have also regarded the TOPCon route favorably. According to Jinko Solar, it is firmly optimistic that TOPCon is the mainstream technology in the next 3-5 years. Trina Solar said that it is currently focusing on TOPCon, which is “the most cost-effective technology route under comprehensive consideration” of the company.
PV cell technology route in the short term is difficult to have a definitive conclusion. Eventually, the market will give the answer. At present, the indisputable fact is that, as a representative of N-type technology, TOPCon has risen strongly this year, and at least 60 companies are carrying out TOPCon capacity layout. Based on incomplete statistics by GreenergyDaily, the total capacity of N-type related landing, construction and planning reached 1000GW.
In terms of capacity and shipment, TOPCon is gradually replacing PERC as the leading product in the PV market. A new race is taking place among the leading enterprises.
Rise
TOPCon’s full name is Tunnel Oxide Passivated Contact Cells. The structural concept of TOPCon cells was first proposed by the Fraunhofer Institute for Solar Energy Research in Germany at the 28th European PVSEC Photovoltaic Conference in 2013.
In 2015, Fraunhofer first increased the efficiency of TOPCon monocrystalline cells by more than 25% to to 25.1%. In 2017, it increased the efficiency of TOPCon cells to 25.8% on 4cm² wafers, demonstrating the efficiency potential of such cells.
The following year, TOPCon technology was quickly developed and applied on a large scale in China. Jinko Solar's TOPCon cells reached a maximum efficiency of 24.19% in 2018; in 2019, a TOPCon “dark horse” company——DAS Solar, took the lead in building the first 1.2GW annual production line for high-efficiency TOPCon cells in China.
By 2022, TOPCon technology entered the “first year”, and its market share increased rapidly. According to the statistics of China Photovoltaic Industry Association (CPIA), in 2022, the market share of N-type batteries has raised to 9.1%, of which TOPCon batteries accounted for 8.3%.
This year, TOPCon is in full swing. According to PV InfoLink’s estimation, by the end of 2023, the nominal capacity of TOPCon will be expected to exceed 600GW, and the module shipment is expected to reach the level of about 120GW, and the market share ratio of TOPCon module products will be around 25-30% in 2023, and it is expected to grow to about 60% in 2024.
In terms of conversion efficiency, TOPCon has also reached record highs. GreenergyDaily learned that a few days ago, DAS Solar released TOPCon4.0 large-area battery efficiency reached 26.33%, which is the current world record for large-area TOPCon battery.
The reason for TOPCon’s strong rise can be attributed to three points:
First, TOPCon has significant technological advantages that drive its efficiency and costs down.
At present, the average efficiency of P-type PERC cells is around 23.5%, while the average efficiency of TOPCon cells mass-produced by the head enterprise has reached more than 25.5%. DAS Solar’s CTO Song Dengyuan told the media that the empirical data applied in various environments show that TOPCon’s power generation is about 5%-7% higher than PERC’s.
In terms of cost, the research report recently released by Huatai Securities shows that the current leading TOPCon battery plant can control the cost difference between TOPCon and PERC within 0.03 yuan/W.
Compared to other N-type technology, TOPCon holds a sufficient cost advantage. Industry insiders say, from the investment cost point of view, TOPCon per production line GW equipment investment is below 180 million yuan, and HJT is between 350 million to 450 million yuan; Moreover, the addition of LPCVD/PECVD equipment and coating equipment to the PERC production line can be upgraded to the TOPCon production line. For the traditional manufacturers, per production line GW transformation cost of 0.8 billion yuan has a higher economic efficiency.
Second, the strong layout of the capital is favorable for TOPCon.
The influx of capital has caused the industry to worry about “overcapacity”. But there are also a number of industry insiders said to GreenergyDaily that more capital influx is a normal phenomenon of market-oriented competition, which will promote technological innovation and costs continue to descend.
One of the more notable examples is the investment in TOPCon’s R&D. Taking DAS Solar as an example, its R&D and professional and technical personnel accounted for 20% of the total number of employees, and the annual R&D investment accounted for about 5% of sales revenue. Currently, DAS Solar has more than 210 patents of various types. It is because of the large and continuous investment in R&D that DAS Solar has been able to renew the efficiency of its TOPCon products several times, and to write the figure of 26.33% on the scale of the world record.
Third, TOPCon has a more complete industrial chain support.
The prerequisite for the industrialization of a technology is the need to form a perfect industrial ecology. The industry generally believes that among N-type technologies, TOPCon has a higher degree of industrial chain maturity. Especially in the past two years, from silicon wafers to cells and modules, from silver paste to equipment and film, TOPCon’s upstream and downstream support is gradually complete, and there is a mature supply system for each link, which has driven the rapid decline in TOPCon’s technology cost.
Dr. Song Dengyuan has also claimed, “It is due to the joint efforts of the entire industrial chain that the efficiency of (TOPCon) cell can maintain constant progress by 0.3%-0.5% per year”.
Concern
Next year, a large amount of new TOPCon capacity will enter the market, and the pace of dominant N-type capacity replacing P-type will accelerate, but there are still concerns about whether TOPCon can be a one-shot deal in the next few years.
The first is the problem of falsely high module power.
Different types of module products have different “standards” for power testing, and PERC technology and products have been in the market for a long enough time to have a unified standard, with less deviation in testing by different organizations. However, N-type products, especially TOPCon, have emerged for a shorter period of time and have not yet formed a unified standard.
According to industry insiders, testing errors, manufacturing process instability, raw material differences, as well as screening of defective products and other factors, will lead to “falsely high” product power; Also, we cannot exclude the possibility that under the fierce competition in the market, to attract customers to purchase, some module enterprises deliberately label “false” power.
According to recent research data from the China Academy of Weights and Measures (CAWM), the power values measured by different third-party organizations for the same module vary from the actual power of the module —— in some products, the measured power value is nearly 14W higher than the actual power, which means that the buyer of the product will have to pay for the non-existent power of 14W.
Second, the dispute between PECVD and LPCVD process route has no result.
The new TOPCon puts forward new process requirements for the production preparation link, and most of the process adjustments can be achieved by slightly upgrading on the basis of the original PERC. However, the thin film deposition process, which is the core of the TOPCon battery technology, should be especially careful in the selection of process routes.
The current mainstream process routes for thin film deposition processes are categorized into Low Pressure Chemical Vapor Deposition (LPCVD) and Plasma Enhanced Chemical Vapor Deposition (PECVD).
LPCVD route has relatively high maturity, good film formation effect and high cell efficiency, but it needs to replace the quartz tube and quartz boat every 3-6 months, and the shortage of quartz undoubtedly will affect the product yield. PECVD, on the other hand, can be in-situ doped and has a streamlined process, but there are problems such as poor film-forming quality and low production yield.
At present, the representative enterprises of LPCVD are Jinko Solar, DAS Solar and Drinda Solar, etc.; While the main manufacturers of PECVD include TW Solar, Trina Solar and so on.
According to Shen Wenzhong, director of Solar Energy Research Institute of Shanghai Jiao Tong University, the choice of process route will determine the vitality of the enterprise, but so far, the choice of PECVD and LPCVD is not very clear. Mainstream and large-scale enterprises choose LPCVD route, while most of the start-ups and new entrants choose PECVD route. The choice of the two routes will surely be split into certain winners and losers in the future.
Third, the industry remains concerned about overcapacity at TOPCon.
Jiang Weipeng, executive president of GCL Integration, once told the media that although TOPCon expanded production ferociously, the actual landing capacity is limited and may not necessarily meet expectations. Especially for cross-border enterprises, the investment of new technology and new capacity still needs a good executive team to implement.
LONGi Solar management recently expressed more pessimistic. They believe that TOPCon “it is expected to have 400GW-500GW capacity to the market in the first half of next year, which will soon enter the state of relative surplus”. Superimposed on the “investment returns do not meet expectations”, TOPCon may “not gain profit once enters the stage of surplus”.
These completely different views mentioned above show the divergence within the industry. An indisputable fact is that in the last one or two years, the scale of industry enterprises to expand production is very alarming. The so-called overcapacity concerns, not only about TOPCon, but also about the entire industry. When the overcapacity appears in the whole industry, advanced and efficient products, on the contrary, are more advantageous. A number of industry authorities believe that under the development of the PV industry, the backward capacity always has surplus, while advanced capacity is always in short supply.
In addition, with HJT, XBC and other technology routes further realizing cost reductions, how TOPCon can stay ahead of the curve in terms of cost has become a challenge that all links in the industry chain are facing. Professor Shen Wenzhong, Director of the Solar Energy Research Institute of Shanghai Jiaotong University and Honorary Chairman of Shanghai Solar Energy Academy, believes that a lot of efforts are being made to overcome the problems in the growth process of TOPCon, both in crystal pulling and slicing, and in the cell and module segments. However, it is hoped that the industry will continue to be calmed and be able to develop TOPCon technology with quality and quantity.
Future
How long is TOPCon’s life cycle exactly?
According to Shen Wenzhong’s judgment, TOPCon will serve as the mainstream product in the PV industry chain for at least 8-10 years. “We can no longer switch from N-type to P-type, which is determined by the principle of physics. The future is definitely the world of N-type technology”. TOPCon is constantly improving itself. “In the future, it will probably be developed to some routes very similar to HJT”.
Dr. Song Dengyuan also believes that TOPCon and HJT belong to the same source of technology. “Their relationship is to promote each other and to progress together”. In the next few years, the technology will be “blossomed”, but TOPCon must be the mainstream.
None another question arises: Who will be the leader among the companies in the TOPCon era?
Huatai Securities recently analyzed that in this round of industrial technology iteration cycle, the leading battery module manufacturers, which are the first to realize the technology research and development and mass production, are expected to fully enjoy the excess income brought by the new technology.
There are many leading manufacturers in TOPCon’s “research and mass production”, among which Jinko Solar, JA Solar, and Trina Solar are leading enterprises that have been deeply engaged in the PV industry for many years. In contrast, DAS Solar, established in 2018, is particularly noteworthy, and the potential of the “dark horse” is often very astonishing.
DAS Solar has firmly chosen the TOPCon technology route since its establishment, and arguably, it joined the industry with the TOPCon gene. DAS Solar has repeatedly renewed records for the conversion efficiency of TOPCon cells. This May, the efficiency of the new TOPCon 3.0 Plus cell exceeded 26.24%, setting a world record of 730mV open circuit voltage. Four months later, the cell efficiency of TOPCon 4.0 core technology independently developed by DAS Solar reached a new high, with a large area cell (with an area of 333.4cm²), the efficiency exceeded 26.33%, setting a new efficiency record in May. The world record of the efficiency of large area TOPCon cells has therefore been renewed again.
So far, DAS Solar N-type bifacial TOPCon 3.0plus has entered the stage of mass production. In terms of production capacity, in 2021, DAS Solar the production capacity was only 3.2GW, and by 2022, it had skyrocketed to 9GW. This year, it is expected that the production capacity of both batteries and modules will reach 30GW.
DAS Solar has also a clear plan for how to further enhance TOPCon’s technical capabilities. Dr. Song Dengyuan recently stated at the “N-type TOPCon Technology and Supply Chain Forum” that the average efficiency of TOPCon at 26% is a node. After exceeding 26%, the battery structure will change. “After that, 27% will be the next node. After exceeding 27%, efficiency can be further improved technically, but the cost is high and not suitable for industrial production”.
Therefore, based on the large-scale production of existing TOPcon, DAS Solar has further laid out core battery technologies such as TBC, CSPC, TSiP, SFOS, etc. Among them, SFOS battery technology is a highly efficient battery technology jointly developed by DAS Solar and the University of New South Wales Photovoltaic Research Center, with a theoretical maximum efficiency of over 40%.
The photovoltage’s energy attribute determines its cost priority, which is the kingly way. DAS Solar has also shown a leading position in leading the collaborative cooperation of the TOPCon industry chain, continuously improving efficiency and reducing costs.
Since 2022, DAS Solar has been researching and developing no-main-grid technology, achieving a significant reduction in silver consumption and bringing a series of benefits, including easy thinning, high welding yield, low equipment cost, improved CTM, and improved reliability. Recently, the main grid free technology equipped with TOPCon3.0 Puls has been integrated into mass production, and it is estimated that there will be cost reduction effects soon.
Additionally, it is worth noting that free busbur is a cost reducing universal technology that can be used on TOPCon, HJT, and even on PERCs that are gradually fading out of the market.
As Song Dengyuan said, “Photovoltaic technology is a wealth of humanity, and its core is the exploration and efficient use of solar energy for power generation. Many principles of improving efficiency and reducing costs are universal, thus the competition of technological routes is not a one-on-one battle, but a mutual promotion. Only the flourishing of photovoltaic technology can promote the healthy development of the photovoltaic industry”.
In the midst of a hundred flowers blooming, optoelectronic technology is moving towards a future of higher efficiency and lower costs. Enterprises that adhere to the main line of technology will soar in the wind and grow into new leaders.
