What is an interconnection bar?
①The composition and function of the interconnection bar The interconnection bar is also called tin-coated copper tape (because it is thin and long, it is called copper tape), the narrow tin-coated copper tape is called the interconnection bar, and the wider tin-coated copper tape is called the bus bar. The interconnection bar is based on red copper, and a layer of tin is evenly coated on its surface.
Red copper is also called oxygen-free copper (oxygen-free copper is pure copper that does not contain oxygen or any deoxidizer residues). The purity of copper reaches 99.95%, the oxygen content is not more than 0.003%, and the total impurity content is not more than 0.05%. Hydrogen embrittlement phenomenon, high electrical conductivity, good processing performance, welding performance, corrosion resistance and low temperature performance. Suitable for highly conductive materials such as terminals, heat sinks, and transformer coils. Oxygen-free copper is elemental copper, and the solid is red. If elemental copper is heated, it reacts with oxygen to produce copper oxide, which is oxygen-containing copper, which is also solid and black. A layer of tin is evenly coated on the surface of the copper strip, the purpose of which is to allow tin to react with oxygen in the atmosphere to generate tin oxide. Tin oxide not only has good corrosion resistance, but is also dense, and has a strong bonding force with copper tape.
The function of the interconnection bar is to connect the cells in the solar cell module with the cells to increase the output voltage of the cell module.
②Technical indicators of interconnection strips and product specifications The technical indicators of interconnection strips packaging are as follows.
Copper base: oxygen-free copper. Copper base resistivity (oxygen-free copper)≤0.01702·mm2/m. Solder composition: 63% Sn, 37% Pb; 60% Sn, 40% Pb; 99% Sn, 1% Ag; 96.5% Sn, 3.5% Ag; 62% Sn, 36% Pb, 2% Ag. Solder melting point: 180～224℃. Tin layer thickness: single-sided coating ≥0.02mm, double-sided coating uniform. Ribbon elongation: soft state ≥20%, semi-soft state ≥15%. Width error: ±0.1mm. Thickness error: ±0.01mm. Packing: paper tray, spool, cut-off carton.
The width and thickness of the interconnect bars range from as small as 0.6mm×0.12mm to as large as 7mm×0.25mm, and the copper-based materials are all oxygen-free copper.