Heterojunction Solar Cells (HJT) Efficiency Comparison
Heterojunction solar cells (HJT) are generally more efficient than traditional crystalline silicon solar cells, including the widely used PERC (Passivated Emitter and Rear Cell) technology. Several key points highlight the efficiency advantages of heterojunction cells compared to traditional solar cells:
Efficiency Comparison
- Heterojunction Solar Cell Efficiency: SHJ cells have demonstrated record laboratory efficiencies up to approximately 26.7%, with commercial average efficiencies around 25.0% in 2023. Flexible heterojunction cells have also reached certified efficiencies of about 26.06%.
- Traditional PERC Solar Cells Efficiency: The average commercial efficiency of p-type PERC cells was about 23.3% in 2023, which is lower than SHJ cells’ efficiency.
- Other Competing Technologies: N-type TOPCon (Tunnel Oxide Passivated Contact) cells have an average commercial efficiency near 24.9%, still slightly below SHJ cells.
- Tandem Cells: Combining SHJ with perovskite in tandem (two-junction) configurations has achieved even higher efficiencies of 33.9%, which is currently the highest reported non-concentrated two-junction solar cell efficiency.
Reasons for Higher Efficiency in Heterojunction Cells
- Superior Surface Passivation: HJT cells have excellent surface passivation resulting in very high open-circuit voltages, consistently over 700 mV, and lower diode saturation current density. This leads to high fill factors and voltage, boosting overall efficiency.
- Bifaciality: HJT cells can be made bifacial, capturing sunlight from both front and rear surfaces, typically achieving bifaciality factors above 90%, compared to around 70% for PERC cells. This feature allows for increased energy yield, especially in installations with reflective ground surfaces.
- Better Temperature Performance: HJT cells have better temperature coefficients than traditional silicon cells, meaning their efficiency decreases less under high temperature conditions.
Summary Table
| Feature | Heterojunction (HJT) Cells | Traditional PERC Cells |
|---|---|---|
| Typical Commercial Efficiency | ~25.0% (up to 26.7% in lab/flex cells) | ~23.3% |
| Open-Circuit Voltage (Voc) | >700 mV | Lower than HJT |
| Bifaciality Factor | >90% | ~70% |
| Temperature Coefficient | Better (less efficiency loss at high temps) | Worse (more efficiency loss at high temps) |
| Tandem Cell Efficiency | Up to 33.9% with perovskite integration | Not typical |
Conclusion
Heterojunction solar cells are significantly more efficient than traditional PERC solar cells, offering both higher power conversion efficiencies and additional operational advantages such as greater bifaciality and better temperature resilience. Their ability to integrate with tandem perovskite layers further pushes their efficiency beyond traditional single-junction limits, making HJT cells one of the most promising modern photovoltaic technologies.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/how-efficient-are-heterojunction-cells-compared-to-traditional-solar-cells/
