The company has used its proprietary Day4 Electrode and distributed by-pass diode technologies to integrate shading protection directly into the solar cells, as opposed to the traditional approach which calls for by-pass diodes to be placed in the centralized junction box area on the back of the solar module. Due to the inherent flexibility of Day4 Electrode integrated by-pass diode technology, shading protection can now be distributed throughout the solar module, reducing product sensitivity to changing solar illumination conditions, and partial solar module shading in particular. While the technology is certainly applicable to all types of PV cells, it is particularly relevant for UMG silicon based solar cells as it addresses one of the key issues of commercial UMG silicon based solar modules – increased sensitivity and potential danger to PV module integrity at the time of partial module shading.
“It is known that UMG based solar cells typically have substantially lower shunt resistance and a corresponding lower value of breakdown voltage compared to conventional solar grade multicrystalline solar cells,” says Professor Leonid Rubin, chief technology officer of Day4 Energy. “This fact imposes a limitation on the maximum number of solar cells that can be connected in series in the solar module in order to prevent irreversible breakdown in case of partial module shading during operation.”

“Our low cost integrated Day4 Electrode by-pass diode technology eliminates this problem and removes some of the existing prejudice against wider employment of this potentially prospective material.”
UMG silicon technology for manufacturing silicon ingots and wafers is widely believed to offer significant potential for cost reduction for the PV industry as a whole. With recent progress made by a number of companies at the silicon purification level, UMG silicon material is starting to make its way into the PV cell production lines. At the same time, PV module technology requires its share of modifications in order to successfully utilize these new UMG silicon based PV cells without jeopardizing the long-term integrity of the final product. Day4’s new technology addresses these issues and removes one of the key roadblocks on the way to implementation of UMG silicon solar cells in large-scale commercial solar module manufacturing. The technology is ultimately enabled by a combination of the company’s proprietary Day4 Electrode technology for contacting and interconnecting solar cells with a proprietary low cost by-pass diode design. The company has applied for patent protection in connection with this invention.

Day4 Energy Inc.
www.day4energy.com