New advancements in solar cell technologies are ripe with acronyms. So much so that it has become its own language amongst industry enthusiasts. With such in mind a surge in popularity is occurring to a once almost dormant solar cell technology; HJT or Hetero-Junction Technology. Supporting improved efficiency characteristics and outstanding temperature co-efficient characteristics, many leading manufacturers have transcended the once limitation of commercial viability required of HJT solar cells. The result, a new era of mass production through feasability awaits.
1.0 HJT Technology
Heterojunction Technology has been proven to increase efficiency, performance, and durability as a mature solar cell technology. Compared to other cell processing technologies, the production process of an HJT cell is more efficient and takes fewer steps. HJT solar cell is also a natural bifacial cell, with a much better stable solar cell colour (HJT Solar|Based on N-type Silicon Wafer n.d.).
1.1 What is a heterojunction solar cell?
A heterojunction (HJT) is a PN junction that combines two technologies into a single cell: a crystalline silicon cell sandwiched between two layers of amorphous “thin-film” silicon. These technologies can be used together to gather more energy than if they were utilized alone (HJT Solar|Based on N-type Silicon Wafer n.d.).
1.2 What is the difference between HJT and PERC cells?
In general, the following are the advantages of an HJT cell over a PERC cell:
- After PERC, there is a higher possibility for efficiency.
- Improved bifaciality The HuaSun HJT Solar module is meant to be bifacial, with over 92% bifaciality.
- HJT’s low-cost production potential and significantly fewer process steps than standard solar cells.
- Low-light performance and a lower temperature coefficient (improved performance in high temperatures) (HJT Solar|Based on N-type Silicon Wafer n.d.).
1.3 HJT Cell Performance
The HJT solar cell structure combines two technologies: a crystalline silicon cell sandwiched between two layers of amorphous “thin-film” silicon. In this approach, thin-film solar has a higher temperature coefficient than crystalline silicon. This high-performance solar cell enables great power generation in all regions worldwide, especially in hotter temperatures (HJT Solar|Based on N-type Silicon Wafer n.d.). For example, excellent low-light performance and improved performance in hot weather.
1.4 HJT Benefits
HJT has a longer lifetime or generating power and thus a larger yield. HJT has a substantially reduced number of process steps than typical solar cells and has a higher efficiency potential after PERC. In addition, in today’s PV market, EPCs are playing a critical role for those seeking the lowest LCOE (HJT Solar|Based on N-type Silicon Wafer n.d.). Furthermore, HJT offers additional benefits: it is a well-suited application for achieving efficiencies of over 23% at temperatures below 200 °C. Compared to the typical solar cell procedure, the entire process flow is simple and involves fewer step (M.Taguchi, et al. 2013). HJT solar cells feature a high module bifaciality of > 90% and a low-temperature coefficient of -0.2%/K, which improves PV systems’ LCOE and output power (Zhao, et al. 2018).
- d. HJT Solar|Based on N-type Silicon Wafer. https://huasun.net/product/hjt-solar-cell/.
- Taguchi, A.Yano:S.Tohoda, K.Matsuyama, Y.Nakamura, and T.Nishiwaki. 2013. IEEE J.Photovolt1-4.
- Zhao, J., M.Konig, Y.Yao, YC.Wang, R.Zhou, T.Xie, and H.Deng. 2018. “>24% Silicon Heterojunction Solar Cells on Meyer Burger’s on Mass Production Tools and How Wafer Material Impacts Cell Parameters.” IEEE Xplore .