#China #Risen Energy #Ningbo #HJT solar #Ultra-Thin Wafers

The Journey of Risen Energy with Ultra-Thin Wafers

In the ever-evolving world of photovoltaic technology, Risen Energy Co., Ltd. has positioned itself at the forefront of innovation, specifically in the realm of ultra-thin silicon wafers for HJT (Heterojunction) solar cells. As discussions around the concept of 'space photovoltaics' gain traction within the industry, fundamental technical attributes such as lightweight design, high power output, radiation resistance, and long-term reliability become increasingly pivotal. This focus has led Risen Energy to leverage its extensive expertise in producing ultra-thin silicon wafers, ultimately achieving significant advancements in solar cell technology.

A Deep Dive into Ultra-Thin Silicon Wafers

Risen Energy's recent technical report, titled "HJT Hyper-ion: A White Paper on Development and Industrial Application of Ultra-Thin Silicon Wafers," outlines not only the practical engineering processes behind mass production but also sheds light on the intricate relationship between wafer thickness and performance.

1. Why Choose Ultra-Thin Wafers?
One of the most compelling justifications for adopting ultra-thin wafers lies in their potential to reduce production costs. In the overall cost structure of HJT solar cells, silicon wafers account for approximately 55% of the total expenses. Thus, minimizing the thickness of these wafers becomes an effective strategy to achieve significant cost reductions. However, this rationale extends beyond economics and is deeply intertwined with the inherent advantages offered by HJT technology. The low-temperature manufacturing process (below 200°C) and the symmetrical structure of HJT cells facilitate smoother wafer processing, thereby minimizing risks such as warping and breakage commonly associated with higher-temperature methods.

2. Balancing Performance and Reliability
Risen Energy has conducted extensive research focusing on three crucial aspects: efficiency, production yield, and mechanical resilience. Initial findings indicate that while the short-circuit current (Jsc) tends to decrease with thinner wafers, the open-circuit voltage (Voc) tends to see an increase. Interestingly, the fill factor (FF) remains fairly stable. Through targeted experimentation, Risen Energy has demonstrated that their HJT Hyper-ion cells fabricated with 110 μm wafers have achieved an impressive average efficiency rate of 26.4%, with the best production batches exceeding 26.6%. This indicates that an optimal reduction in wafer thickness does not compromise maximum performance limits.

Furthermore, by redesigning the wafer cassette configuration from horizontal to vertical stacking and optimizing all automation processes throughout the manufacturing line, they have reported stable yield rates consistently above 99.5% with fragmentation rates below 0.25%. This strategic innovation addresses the manufacturing challenges posed by thinner wafers effectively.

Moreover, comparative tests revealed that while PERC cells measuring 150 μm and TOPCon cells at 130 μm fractured during flexural tests, the flexibility of HJT cells produced at less than 100 μm showcases their remarkable durability.

3. Applications Extending from Earth to Space
Risen Energy's HJT Hyper-ion products, primarily produced for terrestrial power plants, incorporate silicon wafers of 110 μm and solar cell thicknesses of approximately 95 μm. This ideal thickness ensures a harmonious balance between efficiency, cost-effectiveness, and durability. However, exploring applications in the realm of space photovoltaics demands even thinner cells, often requiring thicknesses below 70 μm. Risen Energy's long-standing experience with ultra-thin HJT technology has positioned them to successfully produce cells that meet these stringent requirements.

4. Technological Innovations for Thin Cells
Traditional high-temperature soldering methods fall short when dealing with such thin cells. In response, Risen Energy has introduced the High-Pressure Hyper-link cell interconnection technology, which circumvents the thermal stresses of conventional soldering, aligning seamlessly with the low-temperature characteristics of HJT and the physical properties of ultra-thin cells. Rigorous reliability testing shows that the Hyper-ion modules, utilizing this advanced technology, outperform standard benchmarks for performance degradation.

5. Integrated Research and Development
The journey toward ultra-thin wafers is not merely a series of technological breakthroughs; it embodies a holistic integration of innovations spanning wafers, cells, and modules. The overlap of thinner wafers, low-silver content metallization, collector bar-less cells, and Hyper-link technology coalesces under a unified design philosophy that ultimately redefines the competitive advantage of Hyper-ion products.

As Risen Energy reflects on their pathway to developing ultra-thin wafers, it becomes clear that their commitment to cost reduction, technological integrity, and systematic innovation have been crucial to their success. The publication of their technical report serves not only as a chronicle of their journey but as an invitation to industry partners to collaborate and propel photovoltaic technology towards unprecedented heights of lightness, resilience, and imaginative potential.