In a solar panel, there’s a thin strip of copper or aluminum between cells that conducts electricity called a busbar. It separates solar cells and conducts the direct current the cells collect from solar photons to the solar inverter, which converts the direct current into useable alternating current. The maximum amount of current that can be safely carried is determined by the size of the busbar. It can be as small as 10 mm2. In solar panels, busbars are typically flat strips, which allow heat to dissipate more efficiently because of their high surface area to cross-sectional area ratio. Insulators can support busbars, or insulation may completely surround them.
In the solar industry, busbars are connected to solar panels by welded connections. Busbars are typically contained inside switchgear, panelboards or busways. In solar panels, they are typically contained in busways, with long busbars contained in protective coverings. This arrangement allows new circuits to branch off anywhere along the route of the busway, creating multiple points along of transmission along the solar array.