Feb 22, 2020
The reality of continuously reducing costs for photovoltaic power generation and production has allowed generations of photovoltaic people to continuously improve the production process of solar energy. In new innovations such as new materials, automated tools and machines, manufacturing technology, and packaging materials, lasers have also made a lot of contributions to improving the quality and efficiency of the photovoltaic industry.
The most important thing in photovoltaic production is battery manufacturing. Silicon cells play an important role in photovoltaic power generation, whether it is crystalline silicon cells or thin film silicon cells. In a crystalline silicon battery, a high-purity single-crystal / poly-crystal is cut into a silicon wafer for the battery, and a laser is used to accurately cut, shape, and scribe, and then string the battery.
Solar cell edge passivation
High-energy and high-power lasers can quickly passivate cell edges and prevent excessive power loss. With the laser-shaped groove, the energy loss caused by the leakage current of the solar cell is greatly reduced, from 10-15% of the loss of the traditional chemical etching process to 2-3% of the loss of the laser technology.
Aligning silicon wafers with a laser is a common online process for automatic string welding of solar cells. Connecting solar cells in this way reduces storage costs and allows the battery strings of each module to be arranged more neatly and compactly.
Dicing and cutting
Adopts laser dicing to cut silicon wafers is currently the most advanced. It has high accuracy, high repeat accuracy, stable work, fast speed, simple operation and convenient maintenance.
A significant application of lasers in the silicon photovoltaic industry is the marking of silicon wafers without affecting their conductivity. Wafer marking helps manufacturers track their solar supply chain and ensure consistent quality.
Thin film ablation
Thin-film solar cells rely on vapor deposition and dicing techniques to selectively ablate certain layers to achieve electrical isolation. The layers of the film need to be deposited quickly without affecting the base glass and other layers of silicon. Momentary ablation can cause damage to circuits on the glass and silicon layers, leading to battery failure.
The size of the laser beam center affects the way and location of its ablation. The roundness (or ellipse) of the beam will affect the scribe line projected onto the solar module. If the scribe is not uniform, the inconsistent beam ellipticity will cause defects in the solar module. The shape of the entire beam also affects the effectiveness of the silicon-doped structure. It is important for researchers to choose a laser for accuracy, regardless of processing speed and cost, but for production, such as the short pulses required for evaporation in battery manufacturing, mode-locked lasers are often used.
New materials such as perovskites provide a cheaper and completely different manufacturing process than traditional crystalline silicon cells. One of the biggest advantages of perovskite is that it maintains efficiency while reducing the impact of crystalline silicon processing and manufacturing on the environment. At present, the vapor deposition of its materials also uses laser processing technology. Lasers are also used for vapor deposition of perovskite cells.
The tremendous advances and speeds of laser processing technology are astonishing. With a variety of beam diagnostic options, novices or experts can use a portable laser detector to accurately measure their light source in any compact environment. Lasers have now become the most reliable tool for producing silicon solar cells.