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The dispute over the technical route of photovoltaic cells is becoming more and more fierce.
The content below was translated by Tencent automatically for reference.

SMM: at present, the concept of heterojunction is in full swing in the market. under extreme assumptions, some people in the industry have begun to calculate the possibility of heterojunction equalizing PERC, but at present, professional battery companies and second-line enterprises are obviously faster than head vertical integration giants in heterojunction technology. this is the photovoltaic version of "innovator's dilemma" or the "bright moon shining on Dajiang" of giant enterprises. It's not easy to draw conclusions yet.

But what is certain is that in the short and medium term, the market is bound to face an industrial pattern in which PERC, heterojunction and TOPCon coexist, and the technological war between enterprises has been quietly set off.

The heterojunction battery is really here.

Heterojunction solar cells were first developed by Sanyo Company of Japan in 1990, and the previous equipment was mainly imported. The earlier domestic enterprises were Hanergy, Junshi, Jinneng, Zhong Zhi, etc., with a smaller production scale and belonging to a minority market. With the localization of heterojunction equipment, domestic photovoltaic enterprises, especially second-line and even third-tier enterprises have announced that they will enter. At present, domestic production capacity planning has exceeded 50GW, and it is widely predicted in the industry. The conversion efficiency of heterojunction batteries will exceed 25% in the short and medium term.

However, although there are many enterprises planning to invest in heterojunction batteries and carry out research on it, few of them actually produce results, and the scale of mass production is generally not large.

In "veteran players", the average production efficiency of Jinneng heterojunction has reached 23.85%, and it is expected to reach 24.2% by the end of the year. According to Yang Liyou, general manager of Jinneng Science and Technology, "at present, the cost of Jinneng technology heterojunction products is 138% of PERC, and we are confident that it will drop to 108%. This is only a relatively conservative goal."

Jun Shi Energy took a different approach, launching the HDT polycrystal heterojunction double-sided module creatively at this year's Snec. it is said that its battery conversion efficiency is as high as 23.5%, but the cost is 10% lower than that of PERC.

In "New player", Oriental Risheng is the first to mass produce heterojunction components among the top 10 component shippers. In the latest semi-annual report, Oriental Risheng said that the highest production efficiency of heterojunction batteries has reached 24.2%, and the highest component efficiency has reached more than 22%. The first batch of 9BB heterojunction half-piece low-temperature welding packaging process has been realized, the conversion efficiency of half-piece heterojunction components has exceeded 21.90%, and the decay rate in the first year is less than 2%. The 30-year decay rate does not exceed 16.5%. In addition, the company also mentioned the combination of heterojunction and tile technology. At present, the preliminary work has been completed and the trial production can be done quickly.

Among the top ten component companies that ship, apart from Oriental Risheng, only Ates has actually started the production capacity planning of heterojunction, which is expected to be shipped in the first quarter of 2021. Trina Solar Energy revealed in the semi-annual report that its research progress on heterojunction said that it would soon complete the TUV certification of HJT products, but it did not carry out capacity planning.

Professional solar cell manufacturers have also joined the bureau. The Tongwei HJT cell R & D production line was launched at the end of 2018 and was officially put into operation in June 2019. As of 2019, the highest conversion efficiency of HJT cells has exceeded 24.6%, but the specific progress of HJT technology has not been disclosed in the semi-annual report.

Silver paste is the lock of "N era", and MBB is the key.

However, if heterojunction batteries want to achieve industrialization, cost is still the decisive factor.

The cost of silver paste is the most important factor that restricts the cost of heterojunction batteries. Heterojunction cells need more silver paste, and it is a more expensive low-temperature silver paste. According to the statistics of the 2019 photovoltaic industry development roadmap, the silver paste consumption of P-type batteries is about 114.7mg/, of which 32mg is the back silver. Heterojunction batteries have to be painted with silver paste on both sides, and the consumption is 300mg/ tablets, which is nearly three times the difference in quantity.

According to Anxin, Huachuang and other research reports, low-temperature silver paste is mainly monopolized by Kyoto electronic KEM, the price is about 6500-6800 yuan / kg, and high-temperature silver paste price is 4500-4800, according to the 2019 average 300mg/ piece calculation, the silver paste cost of each battery is as high as 1.95 yuan, while PERC battery even if the same use of KEM silver paste, each cost is only about 5 hair, if the use of domestic high-temperature silver paste price will be even lower. In contrast, the cost of target materials and even the cost of depreciation of equipment are insignificant.

At present, the industry is also working hard to reduce the cost of silver paste, on the one hand, to promote the localization of low-temperature silver paste and silver-coated copper to reduce the price of silver paste, on the other hand, it is through MBB and other technical means to reduce the amount of silver paste, according to SOLARZOOM new energy think tank, silver-coated copper + no main grid can even level the silver consumption of PERC.

But at present, although the localization of high-temperature silver paste is in full swing, the Japanese KE in the low-temperature silver paste market is still in an absolute monopoly position. In order to protect profits, only a small number of domestic enterprises such as Jingyin, Dike, Juhe and other enterprises can achieve exploratory mass production, and the production capacity is not sufficient, and the silver-coated copper technology is not mature.

Therefore, in the short and medium term, the technology for battery companies to save the amount of silver paste will be the key to achieve mass production by narrowing the cost difference between heterojunction batteries and PERC, the most important of which is MBB technology.

Although the main purpose of the application of MBB technology is to reduce the battery power loss, improve the conductivity and reduce the fragmentation rate, the width of the main gate and the width of the fine gate decrease gradually in the process of increasing the number of the main gate, which objectively leads to the reduction of silver paste consumption and shortens the cost gap between the heterojunction and the PERC.

According to the 2019 roadmap for the development of China's photovoltaic industry, 9BB batteries entered the market in 2019, with a market share of 16.5%, saving 25% of silver paste than 5BB batteries.

Therefore, 9BB and even 12BB, no main gate and other technologies combined with N-type silicon wafers have become an important technical means for mass production of heterojunction batteries and catching up with PERC, not only increasing efficiency but also reducing cost. At present, most of the mass-produced heterojunction components use MBB technology. According to the Oriental Sunrise semi-annual report, the company has become the first batch of suppliers to realize the low-temperature welding and packaging process of 9BB heterojunction half-wafers, and there is also related research in the Trina half-yearly report. N-type MBB cut half double-sided double glass and single glass components to achieve mass production capacity as one of the company's research and development goals.

The counterattack of PERC and TOPCon

Of course, in the short term, the market is still dominated by PERC, the expansion of PERC production is still in full swing, and in the medium to long term, which is better, TOPCon or heterojunction also needs to be seen.

Perhaps it is inadvertently inserted, and the increasingly fierce large-size technology objectively prolongs the landing time of heterojunction batteries, because at present, the main processing dimensions of domestic heterojunction equipment are G1 and M6, and after the completion of the heterojunction production line, it is difficult to transform, many enterprises hope that the equipment size can be compatible from 210mm downward, in order to cope with the risk of size, which increases the workload for domestic equipment manufacturers.

In the short term, whether it is mass production efficiency or laboratory efficiency, it is not easy to open more than three points of PERC. Longji announced in 2019 that the laboratory conversion efficiency of PERC batteries reached 24.06%, officially breaking through the previous industry definition of 24% of the ceiling. Longji's mass production record has also exceeded 23%, according to the semi-annual report. Tianhe semiannual report revealed that the conversion efficiency of the new PERC production line reached 22.8%, 22.9%, while Jingao annual report said that the mass production efficiency had reached 22.7%.

In the medium term, the advantage of heterojunction in the face of TOPCon is not obvious, and the winner is not known, because the PERC production line can be upgraded to the TOPCon production line through transformation, referring to the project budget (battery + module) for the technical renovation of the 1GW TOPCon production line and the new 1GW heterojunction production line announced on June 10, with the proposed investment amount of 375 million and 1.2 billion respectively, and the construction period of 18 months and 24 months respectively. The cost varies by 3.2 times. Even if only the equipment and installation costs are taken into account, they are 275 million and 970 million respectively, a difference of 3.53 times.

Therefore, through the technical transformation of PERC production line upgrade TOPCon, whether the cost or time, are far less than the heterojunction, almost the default medium-and long-term future, at least most of the existing PERC production capacity of leading enterprises can be upgraded to TOPCon production capacity.

Among the head shipping enterprises, Jingke and Trina Solar have always been the forerunners of TOPCon batteries. According to the latest release released by the China Photovoltaic Commission, Jingke created the highest efficiency of 24.87% (full area) and 24.90% (aperture area) of TOPCon double-sided cells in China, and even made it clear in the official article "everything you want to ask about Tiger Pro, here": "compare TOPCon and heterojunctions, we comprehensively compare several dimensions. At present, we have chosen TOPCon. " At present, Jingke's Tiger- N-type components have been mass-produced.

Tianhe disclosed in the semi-annual report that the experimental efficiency of TOPCon battery reached 24.58%, the company currently has the highest batch average efficiency of 23.8%, developed diffusion process and successfully introduced into the TOPCon production line, the Yellow River water and electricity production efficiency reached 23.2%, Zhonglai set the R & D target of efficiency > 25%.

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