1. Bypass Diodes which in electronics are known as free-wheeling diodes, are wired in parallel with individual solar cells or panels, to provide a current path around them in the event that a cell or panel becomes faulty or open-circuited. This use of bypass diodes allows a string of connected cells or panels to continue supplying power at a reduced voltage rather than no power at all.
2. Current through a series of solar cells is limited by the resistance, or bias condition, of the “highest resistance” cell. When a cell is shaded, its resistance to the flow of current will increase. The increased resistance of even one cell will limit the overall current that the solar panel can provide to the battery bank. A bypass diode is necessary to avoid this potential inefficiency. Under normal operating conditions, the bypass diode is reversed biased and essentially “invisible” to the overall system.
interconnection of PV cells
http://www.electronics-tutorials.ws/diode/bypass-diodes.html (1.); https://www.centralsemi.com/content/product/applications/alt_energy/solar_bypass_diode_2.php (2.)
Author: Svenja Gutt