Effect of Solder Flux on Resistive Solder Bond Hotspot Generation in Photovoltaic Module Circuit Process and Restoration of Hotspot Module

In photovoltaic (PV) modules, resistive solder bond (RSB) hotspots are the primary cause for a reduction in output power of over 25%. They may be the result of inadequate soldering between the busbars and/or between the busbars and the interconnector ribbon during the circuit assembly procedure for the PV module. This study proposes a straightforward, dependable, and rapid method for reducing RSB hotspots in PV modules using additional solder flux during the circuit soldering process. The soldering of PV modules is examined in accordance with actual conditions present in PV module manufacturers during the manufacture of circuits. Using the tab pull test and the damp heat test, respectively, the bonding strength and dependability of the soldered connectors are evaluated. Connectors soldered with flux have a void ratio of 10% that is five times lower than connectors soldered without flux. In addition, connectors with flux decrease soldering strength by a range of −1.54% to −7.69%, whereas connectors without flux decrease soldering strength by a range of −17.39% to −29.31%. During long-term reliability evaluations on repaired 370A and 370B samples, the RSB hotspots are substantially reduced by incorporating additional flux into the circuit process. In addition, the application of additional solder at the busbar to interconnetor ribbon soldering site prevents RSB hotspots effectively. The results are anticipated to provide comprehensive and straightforward solutions for significantly reducing RSB hotspot failures in commercial PV modules.