Compared with perc battery, heterojunction battery has higher conversion efficiency, which is close to 26% at present. It is expected that it will be further improved after stacking other technologies. However, it remains to be verified whether heterojunction battery can become the next generation mainstream technology after perc battery.

On December 15, the first heterojunction cell sample of Aikang technology was officially produced, and the cell conversion efficiency reached 24.59%, which was nearly 2% higher than the current mainstream technology product perc in the photovoltaic industry.

Since the promulgation of the “May 31” policy in 2018, the subsidy for photovoltaic power generation has been reduced year by year, and the transition to the era of no subsidy has begun. Under the background of declining gross profit rate of the industry, accelerating the technological upgrading of the main product links of the industry chain, such as silicon wafers, battery wafers and modules, has become an important direction for photovoltaic enterprises to enhance their competitiveness.

Among them, heterojunction is the most popular in many reserve technologies. Since the beginning of this year, more and more enterprises have bet on heterojunction and successively announced the layout of gigawatt level heterojunction production capacity. However, in the case that its cost still has no advantage, whether the heterojunction can become the next generation mainstream technology after perc as the industry wishes remains to be verified.

Heterojunction is expected to be the next generation of photovoltaic technology

The voice of heterojunction is rising with the improvement of production line standard

Both photovoltaic enterprises and analysis institutions regard 2020 as the first year of heterojunction cell industrialization.

According to incomplete statistics, since the beginning of this year, the capacity planning announced by the photovoltaic manufacturing end has exceeded 30 gigawatts, and the equipment supplier also said that the company has the production capacity of heterojunction mass production equipment. Up to now, Jinneng technology, Dongfang Risheng and other enterprises have put 100 megawatt pilot lines into operation, and Atlas and other enterprises have also publicly announced that the heterojunction project has started construction.

CSCI believes that the heterojunction has entered the commercial maturity period from the steady climbing period. On the one hand, traditional mainstream enterprises have gradually changed and started pilot production lines one after another. On the other hand, we can see the launch of the whole localization line at the equipment end, which provides the basis for future expansion.

Why does heterojunction stand out among many photovoltaic reserve technologies? Higher and higher technical requirements are the driving factors that can not be ignored. At the end of May this year, the Ministry of industry and information technology issued the “standard conditions for photovoltaic manufacturing industry (2020 version)” (Draft for comments), which clearly stated that the average photoelectric conversion efficiency of new and expanded polycrystalline cells and single crystal cells project products should not be less than 20% and 23% respectively.

This is the highest conversion efficiency of perc battery production line at this stage. Although there is still room to improve the conversion efficiency of single crystal perc battery within the industry, as the technology becomes more and more mature, the time and cost of increasing 1% are also increasing.

Compared with perc, heterojunction has higher conversion efficiency, and the highest conversion efficiency is close to 26%. It is expected to be further improved after stacking other technologies.

Yang Liyou, general manager of Jinneng technology, told the reporter: “heterojunction technology combines thin film and crystalline silicon technology, and has n-type double-sided battery structure. The symmetrical structure can reduce the process steps of the battery to four steps. At the same time, the whole line adopts a low temperature process of about 200 ℃, which not only saves energy, but also effectively reduces costs. “

Cost of equipment localization instead of production begins to drop

Although the technology advantage is obvious, the heterojunction has not been used in the industry for a long time. The main reason is that the production equipment foundation is not reliable.

Everbright Securities pointed out that the heterojunction battery production equipment is not compatible with the conventional crystalline silicon battery route. If photovoltaic enterprises choose heterojunction technology, they can not achieve mass production of new technology by transforming the existing battery production line, and can only invest in building a new production line, which leads to high investment cost in the initial promotion.

Shi Dinghuan, former counsellor of the State Council, also said that the weak link in the development of heterojunction technology is the low degree of equipment localization. Without reliable domestic equipment, it is difficult to reduce the cost.

It is understood that at present, heterojunction production equipment accounts for the majority of heterojunction production cost. Taking the core equipment PECVD as an example, for a long time, the main manufacturers of the equipment are German enterprise meyerberg and other foreign enterprises, which undoubtedly increases the pressure of domestic enterprises to promote heterojunction technology.

Yang Liyou said frankly: “in fact, the industry has long recognized this problem. In recent years, domestic equipment manufacturers have successively invested in the research and development of the whole battery production line to promote the technological development of heterojunction battery. At present, the localization of heterojunction production equipment has made rapid progress, from the previous foreign monopoly to the stage of competition

According to the statistics of CSCI, up to now, the domestic equipment enterprises with the whole heterojunction line include Jiejia Weichuang, Maiwei, Junshi energy and Jinchen. This will greatly reduce the initial investment threshold of heterojunction production line, and lay a solid foundation for heterojunction to become the mainstream choice for photovoltaic enterprises to expand production.

In addition, the reporter found that the team of photovoltaic equipment enterprises entering the field of heterojunction is expanding. Since the second half of this year, a number of enterprises, such as Jingshan Light Machinery Co., Ltd. and jiezao optoelectronics Co., Ltd., have announced that they will develop heterojunction core equipment.

Entering the mass production lead-in period, industry chain coordination promotes development

According to pvinfolink, an industry consultancy, the global heterojunction production will be less than 1.5 gigawatts in 2019. It accounted for less than 1% of the 138.5 gigawatts of global component production last year. The output of heterojunction in China is close to 0.5 GW.

This volume of technology products is known in the industry as the technology in the mass production lead-in period. In addition to heterojunction, TOPCON, IBC and other battery technologies are in this stage. Energy trend, a new energy research center of Jibang consulting, believes that technologies in the mass production lead-in period require enterprises in all links of the industrial chain, such as equipment and auxiliary materials, to cooperate with the product end to optimize the production line. As the products pass the application test of terminal power station, they are expected to enter the market promotion stage.

Even if we enter the market, we still have a “challenge arena” to really become the mainstream technology of the next generation. Industry experts estimate that only when the conversion efficiency and cost of commercial mass production of heterojunction battery are higher than that of perc battery, can it show stronger competitiveness.

In this regard, Yang Liyou believes that technological innovation is a system engineering, and should start from the perspective of the whole system. We should not only pay attention to the device side, but also include the raw material side, battery side, module side and system integration side, and cooperate with each other to promote the development of heterojunction technology.

“At present, the consumption of silver paste in heterojunction battery is about three times that of traditional battery, so it is very important to reduce the cost of low temperature silver paste.” Yang Liyou said, “it is suggested to first introduce the multi main grid technology to reduce the use of silver paste, and then start with promoting the localization of silver paste to reduce the price of silver paste. At the same time, we can also develop base metal mixed paste to further reduce the price of silver paste. It is estimated that the price of silver paste will drop by 50% – 70% in the future. “

It is generally believed that with the continuous acceleration of industrialization, heterojunction technology is gradually approaching.

Editor in charge ajx

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