Cast-mono Module: Sunrise’s new breakthrough
Over the past decade, China’s solar photovoltaic (PV) industry has not only enjoyed a faster iteration of technical routes, but also witnessed a remarkable progress in the field of science and technology. It has thus become one of world’s leading industries marching ahead step by step. In these circumstances, PV companies can succeed in outdistancing their rivals only if they keep fighting tooth and nail on the technology and R&D front.
In line with the development of efficient solar modules in the recent years, monocrystalline PERC technology which is standing out from the traditional modules, becomes more mature in the applications of a large number of PV companies. With the increasingly high market requirement for the quality of silicon material, monocrystalline and polycrystalline battle never stopped, so Sunrise tried a new way to reduce the cost of monocrystalline, namely cast-mono technology, which will create more possibilities for PV applications.
Cast-mono wafer uses the original process of polycrystalline wafers to produce a crystalline structure close to the monocrystalline type, with higher efficiency than polycrystalline and lower cost than monocrystalline. That is, the advantages of Czochralski (CZ) crystal and polycrystalline casting are combined, and polycrystalline copes with the challenge of monocrystalline by the upgraded mono-like product. Experiments show that the solar modules with cast-mono technology not only reduce costs and energy consumption, but also have the advantages of high quality and efficiency.
Cast-mono wafer set off a boom in the PV industry in 2011, but the technology was not mature then. Because of the competition of high-efficient polycrystalline, the technology is not promoted on a large scale. After continuous process and quality improvement, it gradually gains market recognition. Sunrise finds this trend and then proceeds with the development of cast-mono modules. The preliminary tests show that the efficiency gap of the new module and mono module is less than 5W, and LID rate is only 50% of CZ crystal, which results in that, the cast-mono modules using high-quality wafers are comparable in power with the CZ crystal modules a year later.
The cast-mono wafer has a cost advantage compared to the CZ crystal. Sunrise increases the yield of cast-mono cells through automatic selection, and combines with multi-busbar (12BB) technology which can minimize the impact of cracking on power output. Based on the above factors, the BOS and LCOE cost of the owner's power stations will be also further reduced.
The cast-mono module produced by Sunrise has more effective light receiving area and a more perfect appearance. Compared with the octagonal structure of the mono cell, the square cast-mono cell makes full use of the surface area of the module. Taking the wafer size of 158.75mm as an example, the area is increased by 0.8% compared with the chamfered 158.75 mono wafer and 2% compared with the 156mm wafer. In general, an efficient cast-mono module (60-cell) may be encapsulated to 310W.
CZ crystal also faces with the LID problem, but Sunrise’s cast-mono module with similar degradation of poly modules, is lower than CZ crystal in LID rate, because the oxygen content of the module is about 40% less than that of the regular mono module.
The cast-mono module is compatible with all of the technologies of efficient modules. When Sunrise combines MBB technology with it, the resistance loss is effectively reduced, module efficiency is improved, and thus the actual power generation will be greatly enhanced.
In the future, with the development of cast-mono technology and utilization of raw materials, the manufacturing cost of the cast-mono module will still has a large reduced space. The new module is expected to mass production in the second half of this year, when you’ll see a big leap for Sunrise’s PV capacity.