Research reveals that the energy efficiency of a new approach could almost double that of interconnecting standard shingle cells under random shading conditions.
From pv Global magazine
Shingle modules – where silicon solar cells are cut into five or six strips and interconnected using an electrically conductive adhesive – have been around for some time, and although they have never been a common solution. , they have captured the attention of the industry thanks to a potential for flexibility in the size and shape of the modules, better aesthetic appearance and better tolerance to shading.
Recent interest in building integrated and other applications for PV beyond standard rooftop or ground mounted modules, as well as concerns about the use of lead and improvements in electrically conductive adhesives, has recently grown. sparked renewed interest in this approach.
In October, the German Fraunhofer Institute for Solar Power Systems (ISE) presented a new configuration for shingle cells, developed in collaboration with interconnect equipment supplier M10, which it calls Matrix Shingle Technology. . The approach sees bands of cells arranged in staggered rows, much like bricks are placed in a wall. Fraunhofer ISE claims this leads to higher module efficiencies and even better shading tolerance, and now sets out to evaluate the performance of the technology in various installation scenarios.
The institute’s latest work, published in Progress in Photovoltaics, demonstrates that Matrix shingle modules offer a significant advantage under certain shading conditions. The institute conducted laboratory experiments for various shading scenarios by partially covering the modules with a black tarp and then testing them in a solar simulator.
When the shadow moves diagonally through a module and under random shading conditions, the Matrix modules have been shown to perform significantly better. Under diagonal shading, the group recorded up to 73.8% more power, and under random shading up to 96.5% more power, compared to an advanced shingle module using the approach. standard rope.
The group explained that their approach allows more electric current to flow out of the module, without being blocked by shaded areas. “This is caused by currents bypassing the shaded area through the metallization of the busbar transversely to the normal current flow. “Besides higher power outputs, this leads to much less MPP where the reverse bias of parts of the module increases the risk of hot spots occurring. “
While shingle modules are already known to be less sensitive to hot spots thanks to better heat dissipation through contacting cells, the group also saw a 40% reduction in the risk of bypassing parts of the module. , which further reduces the risk of hot spots forming. .
ISE scientists further note that they expect increased current extraction to improve module energy yields in power plant applications that would not have to cope with the shading, although they would have to do additional work to demonstrate it.
Fraunhofer ISE has previously stated that it has a prototype production line for Matrix shingle cells operational in Freiburg, and now adds that it sees the technology as particularly attractive for photovoltaics integrated into buildings or vehicles, and other applications where frequent shading would be unavoidable. “The enormous potentials of solar power generation respond to a wide variety of irregular shading conditions, making shade tolerance a very important aspect,” they conclude. “Above that, the matrix modules meet other requirements such as a highly aesthetic appearance without loss of power due, for example, to coloring or printing of patterns on the front sheet.
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