IBM has announced it has made a research breakthrough in photovoltaics technology that could reduce the cost of harnessing solar power for electricity.
Using a large lens to concentrate the sun’s power, IBM researchers are able to capture a record 230 watts onto a centimetre square solar cell, in a technology known as concentrator photovoltaics (CPV). That energy is then converted into 70 watts of usable electrical power, about five times the electrical power density generated by typical cells using CPV technology in solar farms.
By using a much lower number of photovoltaic cells in a solar farm and concentrating more light onto each cell using larger lenses, IBM’s system enables a significant cost advantage in terms of a lesser number of total components.
If it can overcome additional challenges to move this project from the lab to the fab, IBM believes it can significantly reduce the cost of a typical CPV-based system.
The main breakthrough IBM made revolves around the ability to cool the tiny solar cell. Concentrating the equivalent of 2000 suns on such a small area generates enough heat to melt stainless steel, something the researchers experienced first hand in their experiments. However, by borrowing innovations from its own R&D in cooling computer chips, the team was able to cool the solar cell from greater than 1600 degrees celsius to just 85 degrees celsius.
The IBM research team developed a system that achieved breakthrough results by coupling a commercial solar cell to an advanced IBM liquid metal thermal cooling system using methods developed for the microprocessor industry.
Specifically, the IBM team used a very thin layer of a liquid metal composed from a gallium and indium compound which they applied between the chip and a cooling block. Such layers, called thermal interface layers, transfer the heat from the chip to the cooling block so that the chip temperature can be kept low. The IBM liquid metal solution offers the best thermal performance available today, at low costs, and the technology was successfully developed by IBM to cool high-power computer chips earlier.
“We believe IBM can bring unique skills from our vast experience in semiconductors and nanotechnology to the important field of alternative energy research,” said Dr Supratik Guha, the scientist leading photovoltaics activities at IBM Research. “This is one of many exploratory research projects incubating in our labs where we can drive big change for an entire industry, while advancing the basic underlying science of solar cell technology.”
By Niall Byrne