What is realistic current for TOPCon cells? - LinkedIn

The Quantum Efficiency (QE) results gave some interesting insights for TOPCon cells. As can be observed the TOPCon cell has a better UV response compared to a 22.45% PERC cell (Now industrial PERC cels might have a better UV response). The interesting difference lies in the longer wavelength region, where the TOPCon cell had a lower response compared to the PERC cell! The poly-Si thickness for these TOPCon cells would be around 120 nm (for those TOPCon cells). So it can be inferred that the poly-Si layer on the rear-side leads to significant absorption of longer wavelength photons though its reflection is less compared to the PERC solar cell. This also points to a push for reduction of the poly-Si thickness or using methods to selectively reduce the poly-Si thickness in the non-contact region on the back-side.

If you want to learn more, please visit our website KINGSUN.

Integrating the EQE curve over the wavelength range from 300 nm to 1,200 nm in intervals of 5 nm with the AM1.5 G power density spectrum converted to normalized current over the wavelength range and taking into account the front-side metallization shading (2.9%) (phewww), leads to a Jsc value of 40.66 mA/sq.cm! For an M10 cell with area of 330.16 sq.cm, this corresponds to an Isc value of 13.42 A. Just to mentioned the QE with 100% response over the entire range leads to a Jsc of 46.46 mA/sq.cm. The Jsc of the 22.45% PERC cell was calculated as 40.5 mA/sq.cm.

Looking at TOPCon cell datasheets of top manufacturers, all of them quote Isc value of > 13.6 A for M10 wafer size & efficiency label of 25%. In a conservative scenario, the 'quoted' Isc is higher by at least 1.5% relative compared to the actual value. This leads to a decrease of absolute 0.9% efficiency for a 25% rated cell assuming the FF is measured accurately!

Now the M10 cells are of 182.2 mm x 182.2 mm size, so the realistic Isc value might be little higher. So then the efficiency might be higher by 0.5%-0.7% absolute in my estimate.

For more information, please visit TOPCon PV Cell.

This is very important for the TOPCon cells, as the module manufacturers will 'expect' a certain module power, but will mostly get reduced power and would wonder why the CTM loss is higher? The higher indicated Isc definitely has a part to play in this!

A good recommendation for the TOPCon module manufacturers would be to have a reliable solar cell I-V flasher for IQC with a certified golden cell with clearly defined conditions for calibration. This would help to separate the milk from the water. :)

In addtion to the above points, we will also present some other interesting I-V analysis and simulation studies in a poster (1BV.5.28) at the EU PVSEC (in around a month's time) which my colleague Dr. Gourab Das and Lejo Joseph Koduvelikulathu would be attending.

For more Solar Power Inverterinformation, please contact us. We will provide professional answers.