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on september 6, the "2024 hjt heterojunction & stacking industry summit" kicked off in shanghai. hundreds of representatives from industry enterprises, financial institutions, third-party think tanks, etc. jointly put forward suggestions for the larger-scale development of hjt heterojunction products in the photovoltaic field.

according to incomplete statistics from solarzoom, as of early september, a total of 10.33gw of hjt heterojunction products were tendered in 2024, an increase of nearly an order of magnitude compared to 2023. by the end of 2024, the actual shipment of hjt heterojunction is expected to reach 30gw, entering a new stage of large-scale development.

on the supply side, unlike the rapid expansion of topcon batteries, photovoltaic companies are much more conservative and cautious about the expansion of hjt heterojunction. as of the end of june 2024, data from solarzoom new energy think tank showed that the effective production capacity of hjt heterojunction batteries was only 42.3gw, and the capacity under construction was 55.5gw. among them, the largest scale is huasheng new energy, with a capacity layout of more than 20gw.

at the same time, when the hjt heterojunction route can become profitable has always been the most concerned topic in the industry.

ma yiwei, vice president of solarzoom, explained at the meeting that in the context of abundant production capacity, there are only two ways for hjt technology to achieve full profitability: continue to reduce costs and increase efficiency. he pointed out that the advanced production capacity of hjt batteries has currently achieved an average mass production conversion efficiency of more than 25.6%, and the power generation per watt (or the number of effective power generation hours of power stations) in medium-high temperature and medium-high ground reflectivity scenarios is more than 3% higher than the mainstream battery technology. if priced by production cost, given that the current cost gap between hjt batteries and mainstream technology routes (at the same scale) has narrowed to 0.04-0.05 yuan/w, the lcoe of hjt batteries in most locations around the world is already lower than the current mainstream route. by 2025, the conversion efficiency of hjt batteries will still have room for improvement of no less than 0.5%, and the average mass production module shipment power is expected to reach 740w+; the production cost per watt will surpass the mainstream technology route due to the introduction of 0bb technology in mass production, economies of scale, and commodity price increases, so the lcoe of hjt products calculated by production cost will be further reduced. "production costs are lower than mainstream technologies in all aspects + power and power generation advantages accumulate to 5% = undisputedly surpassing the mainstream battery technology route and accelerating disruption and iteration", by then, we will see the grand occasion of full profitability of hjt heterojunction and future hjt & stacking technology.

in ma yiwei's vision, equipment cost reduction is an extremely important and critical part of the entire hjt heterojunction process to achieve full profitability. zhou jian, chairman of maxsun technology, a leader in hjt equipment, introduced maxsun's latest hjt 4.0 production line on site. compared with the previous 3.0 production line, the new 4.0 production line not only has a larger production capacity, reaching 1.2gw for the entire line, but also saves 34%+ of equipment floor space, reduces on-site personnel by 25%+, reduces equipment power consumption by 20%+, reduces facility power consumption by 30%+, reduces plant facility investment by 30%+, and reduces target material consumption by 1.5mg/w. under the combined effect of multiple measures, the 4.0 production line can reduce non-silicon costs by 2.5-3 cents/w. at the same time, zhou jian proposed an updated vision for the development of hjt heterojunction in 2024: in less than 4 months, the mass production efficiency of hjt batteries will strive to surpass 26%, the specifications of 210/66 heterojunction modules will strive to approach 750w, the silicon wafer thickness will be less than 100μm, the slurry dosage will be less than 12mg/w, the silver content will be close to 30%, the indium dosage will be less than 1mg/w, and even completely indium-free heterojunction batteries will appear, and the efficiency of heterojunction perovskite stacked batteries will exceed 30% in full size.

among all the cost reduction solutions, the target material is the one that is mentioned repeatedly. dr. lu kuankuan, director of the thin film center of olai new materials, introduced the progress of indium-free targets to the participants. he said that the current olai indium-free first-generation products superimposed with high-efficiency targets can achieve a cost reduction of 16.76%, but it will only cause the heterojunction battery efficiency to decrease by 0.03-0.05%. the second-generation products that are being verified are expected to have a greater cost reduction of up to 33.52%, and the battery efficiency reduction will also be less than 0.05%. in addition, the high-efficiency targets that are also being verified are superimposed with optimized silver paste contacts, which can reduce costs by 16.76% and increase efficiency by 0.1+%. in the future, the high-efficiency targets superimposed with ped targets will combine all the advantages of previous products, reduce costs by 33.52%, and increase battery efficiency by 0.1+%. it is one of the cost reduction measures worth looking forward to for the future new quality productivity hjt heterojunction.

when discussing cost reduction and efficiency improvement, the silicon wafer link cannot be avoided. the cost of silicon wafers is also the largest part of the cost of heterojunction batteries. wang jin, vice president of huasheng new energy and general manager of the silicon wafer business unit, shared his thoughts on the direction of heterojunction-specific silicon wafers. he pointed out that the deep-seated requirements of heterojunction batteries for silicon wafers are nothing more than lower unit watt cost, more stable efficiency output and finer size. in response to these requirements, in terms of technology, comprehensive considerations should be made from fbr+ccz, se ingot, ultra-thin half-cut high-precision silicon wafers, and precise impurity absorption; in terms of cost, comprehensive cost reduction should be carried out from each step of silicon materials, crystal pulling, slicing, and impurity absorption; as for the quality of silicon wafers, it is necessary to start with phosphorus antimony co-doping, ccz, graded impurity absorption and polishing to achieve both comprehensive cost reduction and effective improvement of crystal rod utilization.

wang jin believes that only the combined efforts of multiple technologies from multiple angles and dimensions can provide a more powerful economic impetus for hjt heterojunction.

as a representative of heterojunction battery companies, jiang fangdan, director of the photovoltaic research institute of the photovoltaic technology department of tongwei co., ltd., reported on the progress of tongwei's heterojunction batteries on site. jiang fangdan said that tongwei's 1gw hjt heterojunction pilot line mainly revolves around three core technologies: copper interconnection, 0bb and double-sided microcrystalline technologies: in terms of batteries, the weekly average efficiency of hjt batteries based on mass production processes and slurry consumption exceeds 25.25%, and the weekly average a-level rate reaches 99%. through the introduction of other processes and technologies, it is expected that the battery efficiency can be further improved by more than 0.5%; in terms of components, based on mass production batteries and component bom, the average batch power of hjt components has reached 744.3w, and the maximum power of a single component is 748.1w.

looking to the future, jiang fangdan believes that the industrialization paths of heterojunction will inevitably diverge: one will be efficiency-oriented, forming a generation gap of more than 20w; the other will be cost-oriented, forming a cost advantage over other technologies in similar power ranges.