Solar PV technology trends: A comparative assessment of PERC, SHJ, and TOPCON technologies

Solar cell technology is constantly evolving, with manufacturers and researchers always seeking ways to increase efficiency, reduce costs, and improve reliability. In recent years, three cell technologies have emerged as leaders in the industry: PERC, SHJ, and TOPCon. In this article, we will compare and contrast these three technologies and explore their drivers, benefits, potential risks, and challenges.

PERC (Passivated Emitter and Rear Cell) PERC technology is an evolution of the conventional crystalline silicon solar cell. It incorporates a passivation layer on the rear side of the cell, which reduces surface recombination and improves carrier lifetime and cell voltage. PERC cells typically have a voltage of around 720 mV and can achieve efficiencies of up to 23%.

SHJ (Silicon Heterojunction) SHJ technology uses a combination of crystalline silicon and amorphous silicon layers to create a heterojunction. This allows for superior surface passivation quality, which improves carrier lifetime and increases cell voltage even further. SHJ cells typically have a voltage of around 750 mV and can achieve efficiencies of up to 24%.

TOPCon (Tunnel Oxide Passivated Contact) TOPCon technology is a newer technology that is fundamentally compatible with the conventional Si solar cell process. It uses a physical separation of rear metal from bulk Si, which reduces surface recombination and improves carrier lifetime and cell voltage. TOPCon cells are inherently bifacial and can achieve very high bifaciality. They have a voltage of around 730 mV and can achieve efficiencies of up to 25%.

Drivers & Benefits The main drivers of these technologies are increased efficiency, improved surface passivation, and reduced light-induced degradation. The benefits of these technologies include higher power output, improved temperature coefficient, and reduced sensitivity to metallic impurities. TOPCon and SHJ technologies are inherently bifacial, which means they can capture sunlight from both sides of the cell and increase power output. This also makes them ideal for building-integrated PV applications, where the panels can be used as both a facade and a power source.

Potential Risks & Challenges While these technologies offer many benefits, there are also some potential risks and challenges. One of the main challenges is that current production cells are close to practical efficiency limits, so further improvements will be difficult. TOPCon and SHJ technologies have higher tool costs and a substantially different manufacturing process, which may increase the cost of production. Additionally, there may be concerns about reliability and durability with these newer technologies, particularly as they have less production history than PERC cells.

Another challenge with TOPCon and SHJ technologies is that their bifaciality is lower compared to PERC cells. This means that they are less effective at capturing sunlight from both sides of the cell, which can limit their power output in certain applications.

Summary In summary, PERC, SHJ, and TOPCon cell technologies all offer significant benefits for solar cell efficiency and performance. Each technology has its unique strengths and weaknesses, and the choice of which to use will depend on the specific needs of the application. The table below summarizes the comparison between these technologies.

As the solar industry continues to grow, we can expect to see further advancements in solar cell technology. With the ongoing demand for renewable energy, there is a growing need for more efficient and reliable solar cells.