Today, lasers are commonly used in the field of solar cell production, such as pulsed Nd: YAG lasers or Nd: YVO4 lasers for edge isolation of solar cells. In solar cell production, the back electrical connection is achieved by laser drilling, laser cutting, and laser scribing of silicon wafers. These methods are also considered as feasible laser processing methods. To achieve this method, a pulsed laser with high peak power and good beam quality is required.
Although high-power semiconductor lasers cannot achieve these parameters, high-power semiconductor lasers still have their advantages when using a compact continuous light source with a millimeter-level focus. The following will focus on the application of lasers in the field of solar cell production, and describe how it can achieve welding, recrystallization or drying functions. All these applications have something in common-target calorific values can be reached within a few square millimeters.
In the production of photovoltaic modules, individual solar cells are electrically connected to each other by soldering connection tapes. When soldering, the solder must achieve a certain level of good electrical conductivity at the same time. We rarely use Kolben welding due to its uncertain heat input and mechanical stress during application. Instead, we prefer to use welding methods such as induction brazing, hot air welding or miniature flame brazing.
As the production of solar cells tends to become thinner and thinner (<200 μm), in the production process, the requirements for cheap and high-quality silicon solar cells on their wafer processing are becoming higher and higher, and should be reduced as much as possible Wafer rejection rate and thermal stress during processing.
Another method of laser welding technology to produce solar cells is laminated laser welding. The advantages are:
1. The connection on the back of the unit can be realized by processing one side of the solar cell with a laser.
2. Minimize the time of the time-consuming battery processing process
3. No need to use wire at all (by connecting unit)
4. Processing of fragile ultra-thin solar cells will be more convenient
