Double-faced cell innovation will boost solar power efficiencies
19-04-2017 | By Paul Whytock
The power-generation potential of solar cells has received a significant boost following the development of a highly efficient bifacial cell.
The cell design was facilitated by nano-electronics and digital technology organisation Imec and bifacial solar cells are capable of capturing light on both front and back sides which means they can take advantage of a variety of sources of light that are not necessarily direct. Examples of this indirect light included light reflected from the ground and buildings, diffused light during cloudy weather and sunrise and sunset light.
Imec says tests indicate that during a lifetime operating period these cells might generate 10-40% more electricity than traditional monofacial cells. This will depend however on their bifaciality, the PV installation properties and their location. This may result in an estimated levelised cost of electricity (LCOE) reduction for photovoltaic (PV) installations of up to 30%
The Imec bifacial n-PERT solar cells are created using what it says is an industrially compatible process which provides a front-side conversion efficiency of 22.8%.
They have thin and narrow (< 20 µm) nickel-silver (Ni/Ag) plated fingers on both the n+ and p+ side of the cell and feature contacts that are fabricated in a patented process of simultaneously plating both cell sides. This cell plating is performed on cassette level (simultaneous plating on a full cassette of wafers in a chemical bath) without the need for an electrical contact to be made to the substrates. This results in a solar cell batch with an average conversion efficiency of 22.4% with the best cell demonstrating a record efficiency of 22.8%.
These evaluations were measured internally based on an ISE CalLab calibrated reference cell with a GridTOUCH system under standard test conditions using only front side illumination and a non-reflective chuck.
