Fremont, California solar startup Solyndra has been getting a lot of attention lately for its cylindrical solar panels (see the Ecogeek story here).Â Instead of traditional solar panels, which are flat, Solyndra’s thin-films are rolled into tubes.
According to the company, its panels are more productive than flat cells because they can capture direct, indirect and reflected light across their 360-degree photovoltaic surface (see Solyndra’s drawing and explanation here).Â
In addition, the cylinders are mounted horizontally and packed close together so they cover more surface area and collect more sunlight.Â By contrast, conventional flat panels are angled and spaced apart soÂ the sunlight striking the spaces between the panels is not collected.
The Solyndra panels also are easier and cheaper to install than conventional panels because of the simple horizontal mounting. Â In addition,Â the fact that they are lightweight and allow wind to blow through them often obviates the need for additional anchoring structure.
Solyndra has at least two patents that cover its cylindrical solar panels.Â U.S. Patent No. 7,196,262 (‘262 patent) is entitled “Bifacial elongated solar cell devices” and is directed to a solar cell assembly (400) having elongated solar cells (402).Â Â Â
Each solar cell (402) has a conductive core (404) and a semiconductor junction (410) around the circumference of the core.Â An outer transparent conductive oxide layer (412) is on top of the semiconductor junction layers (410) and completes the circuit.Â
According to the ‘262 patent, this assembly provides the advantages of 360-degree solar cell exposure and electrical connection in series to increase voltage and minimize resistive lossesÂ across the system.
U.S. Patent No. 7,394,016, entitled “Bifacial elongated solar cell devices with internal reflectors,” improves upon the ‘262 patent by adding internal reflectors to the solar panel assembly.Â The reflectors are placed in between two solar cells and reflect sunlight so that a portion of the light is reflected on each adjacent solar cell.
OneÂ indication that people are favorably impressed with Solyndra is that the companyÂ recently announced sales contracts worth about $1.2 billion.