When one (or more) solar photovoltaic cells becomes faulty or provides no power due to shading, the current then flows through the solar bypass diode and prevents hot spots and losses in yield.
When part of a photovoltaic panel is shaded, the shaded cells will not be able to produce as much current as of the unshaded cells. Since all cells are connected in series, the same amount of current must flow through every cell. The unshaded cells will force the shaded cells to pass more current. This causes the solar panel to heat up, have a severe power loss. As a result, those shaded solar cells become consumers of electricity instead of producers.
The function of bypass diode is, when a cell or a panel becomes shaded its bypass diode becomes “forward biased” and begins to conduct current through itself. The effected portion of the solar panel is bypassed, thus drastically reducing the amount of local heating & current loss at the shaded area.
[Publisher: altE Store’s Educational Video Channel]