As we all know, solar photovoltaic modules have a warranty life of 25 years, which can even be extended to 30 years. Thirty years is a long time, but it is not eternal life after all. In fact, the first batch of large-scale photovoltaic systems have gradually reached the age of retirement. What to do after the components fail? Next, we will discuss the recycling of solar panels.

Reuse batteries inside solar panels. Many times components that fail are because the backplane is broken, the film is discolored, and the glass is broken, but the battery itself is still strong. The battery is the most valuable part of the component. The natural idea is to recycle the batteries and reuse them. However, it is difficult to disassemble the components without damaging the battery inside. After tearing off the back panel, you must either soak in hydrochloric acid to remove the EVA film (time-consuming and damaging to the metal battery); or use organic solvents to remove the EVA (more time-consuming); or Ultrasonic waves can destroy EVA (consuming electricity); or heat and pyrolyze EVA (battery is basically useless). The ideal is very full, but the reality is very skinny. If you want to recycle batteries whose performance is not affected, it is basically impossible!

Reuse silicon wafers inside solar panels. Since the battery cannot be recovered, we have to settle for the next best thing and reuse the valuable part of the battery - the silicon wafer. After recycling, the silicon wafers are remade into batteries. This requires various chemical methods to remove silicon nitride, metal electric, emission and back electric fields. The specific combination may be hydrofluoric acid, nitric acid, sodium hydroxide, potassium hydroxide, etc. The reality is once again harsh - God is not as good as man. With the development of technology and the requirement of cost reduction, the thickness of silicon wafers has dropped from 300 microns to less than 200 microns and will continue to decrease. The result is that silicon wafers It simply cannot withstand the torment of chemical treatment - broken into pieces! This road is blocked again.

Repurposing solar-grade silicon. Since silicon wafers cannot be recycled, let’s take a step back and recycle solar-grade silicon. Although we have to redraw the single crystal or cast it into ingots and then slice it, at least we save the purification step! This solution is the mainstream direction today. If it breaks, just let it break. If it breaks, we can just pull the crystal or cast it into ingot again. Like the previous method, front emission and back electric fields are not required. Use sodium hydroxide to quickly remove a few microns of the surface layer, and then use sheet resistance to check whether the emission and back electric fields have been completely removed, and then you can make usable solar-grade silicon.