A small product with a big role – Photovoltaic Ribbon

1. Brief introduction of PV ribbon

Photovoltaic ribbon, also known as tinned copper tape or tinned copper tape/sub-connector tape/interconnector ribbon. The conventional size of PV ribbon is generally: 1-6mm wide, 0.08-0.5mm thick, with a 10-30um thick flux coating. We usually use it for the connection between PV module cells.

The PV cell wafer connected by the PV ribbon is encapsulated by EVA film, PV glass, backsheet, frame, and other materials to form the PV module. Then we can apply it to the construction of the PV power generation system. The quality of tabbing wire is related to the transmission efficiency and service life of photovoltaic modules. The size, mechanical properties, surface structure, resistivity, and other performance indicators of PV ribbons are important factors affecting the efficiency of PV power generation, the fragmentation rate of PV cells, and the long-term reliability and durability of PV modules.

2. PV ribbon on the role of modules

PV ribbon is an important raw material in the process of PV module welding. The quality of PV ribbon will directly affect the efficiency of the PV module’s current collection. And it has a great impact on the power of the PV module.
We must weld the PV ribbon firmly in the process of the series connection of cells, to avoid the occurrence of a false welding phenomenon. Therefore manufacturers in the selection of PV ribbon must base on the characteristics of the selected cell to decide what state of PV ribbon.

Manual welding requires the softer the state of the tape the better, soft state of the tape in the soldering iron will be very good, and battery contact after walking together, the welding process produces very little stress and can reduce the rate of fragmentation. But too soft solder tape will reduce the tensile strength, and it is easy to pull off. For the automatic welding process, the tape can be slightly harder. So that it is conducive to the welding machine to straighten the tape and pressure welding, too soft tape with machine welding is easy to deform, thereby reducing the product yield.

The photovoltaic ribbon is a key component in solar panels. It is an important factor in improving the efficiency and durability of solar panels. The high efficiency and durability of solar panels can only be achieved by using high-quality PV ribbon that is properly installed in the solar panel. So the quality of the PV ribbon and its welding to the solar cell is an important factor in ensuring the efficiency and durability of the solar panel.

3. Selection of PV ribbon

The thickness of the PV ribbon is determined by the thickness of the cell and the amount of short-circuit current. And the width of the PV ribbon should be the same as the width of the main grid line of the cell. The softness and stiffness of the PV ribbon generally depend on the thickness of the cell and the welding tool.
Usually, we divide the PV ribbon into interconnection ribbons (connected to the cell. We weld it on the grid line with the cell). And busbar ribbon (connected to the cell string and junction box) according to the purpose.

The main raw materials for the photovoltaic ribbons are copper and tin. The base material and a surface coating compose them. And the base material is copper of different sizes and requires precise specifications, good electrical conductivity, and certain strength. The surface coating is tin alloy. It can be coated with tin alloy and other coating materials in a certain composition ratio. And thickness evenly on the surface of the copper base material using special processes such as electroplating, vacuum deposition, spraying or hot dip coating. Since the copper substrate itself does not have good soldering performance. The main function of the tin alloy layer is to make the tabbing wire meet the solderability and to firmly weld the photovoltaic ribbon to the main grid of the cell, so as to play a good current conductivity.

4. Interconnection ribbon and busbar ribbon

Usually, we use the interconnection ribbon to connect cells in series, welded on the main grid of the cells. And it has the function of collecting and transmitting the current of photovoltaic cells.
The busbar ribbon is a ribbon connecting the photovoltaic cell strings and the junction box, without direct contact with the cells. And it has the function of transmitting the current of the photovoltaic cell strings.

Both are required in a typical silicon solar cell. And we solder Interconnecting ribbons true to the silicon crystal to connect the solar cells in the solar panel to each other. And the interconnection ribbon carries the current generated by the solar cells to a PV bus. Which is a hot-dipped, tinned copper conductor mounted around the perimeter of the solar panel. And it connects the interconnection ribbon to a junction box. Thin film solar panels generally only require a busbar.