Active Solders For Solar Panel Manufacture

In recent years, active solders have made their way into use in solar panel manufacture. To understand where S-Bond solder alloys are being used one has to understand the solar panel construction. Solar panels consist of arrays of solar cells, soldered together. A solar cell consists of three basic elements, top contact, base and rear contact, as shown in Figure 1. From the back of each solar cell, electrical contact needs to be made between these surfaces to close the circuit and provide an electron path as photons emit electrons in the semiconductor polysilicon photovolatic (PV) cell which migrate to the back of the exposed cell surface, as illustrated.

Solar Cell IllustrationFigure 1. Illustration of solar cell.


Bonding Graphite Felts To Metals

Graphite and carbon felts are increasingly being used for applications in solar, LED, medical, semiconductor, automotive and energy storage systems.

S-Bond Technologies (SBT) has customized it S-Bond (S-B) processes to bond graphite felts to metals for such applications. In the process, graphite felts are first S-B metallized using a paste and vacuum process to create a metallurgical bond between graphite and the SBT active solder filler metals. After S-B metalizing of the graphite, only the tips of the felt surfaces are metallized and thus solderable to the opposing metal plates that are coated with SBT active solders.  The S-B metallization process does not fill the open cells of the graphite felts with S-B alloys, hence its advantage for bonding open cell structures.