Various failures occur in the manufacture, transportation, installation, and aging of solar panels. The author will introduce the examples and accumulated knowledge of Chemitox (Tokyo, Ota) in the evaluation service for the method of detecting these faults.
This article describes a typical failure of a solar cell (power generation component) - a busbar (rough metal wiring on the cell) disconnection case. This failure is caused by soldering of the bus bar in the manufacturing process, resulting in poor wiring.
The problem of poor soldering and the solder material itself is the cause.
After the solar panel is set up and starts to generate electricity, since the temperature in the setting environment changes greatly with time, the contact failure of the solder becomes more and more serious, and the contact resistance between the unit and the bus bar increases, even if It is capable of generating electricity, and many of the currents here are also converted into heat and lost.
During the day, due to the continuous flow of electricity, heat will continue. If this state continues, the wire will carbonize and may become a fire afterwards.
In a natural environment where temperature changes greatly, solder breakage will become more and more serious. Summary of busbar disconnection (Source: Chemitox)
The resin back film on the back side will be burnt and the protective glass on the surface may be damaged.
The bus disconnection that caused this failure can be discovered in advance. Because at the beginning of the disconnection, the output power will show a unique change.
At the beginning of the busbar disconnection, when the amount of power generation is large, the temperature will rise higher and the output power will be greatly reduced. Conversely, when the amount of power generation is small, the temperature will decrease and the output power will approach normal.
For example, when the power generation amount is monitored in units of strings (units in which solar panels are connected in series), a panel that exhibits a change in output power unique to the initial stage of busbar disconnection can be found by a difference in output power with other strings. The string of the group.
To check the solar panel exhibiting such symptoms, you can check the thermal imaging image, perform EL (electroluminescence) inspection, or detect the IV (current-voltage) characteristics, and you can confirm the disconnection caused by poor soldering, etc. The situation is gone.
Nantong Boxin Electronic Technology Co., Ltd. , https://www.ntbosen.com