Tiled solar cell laser process
In an example, the present invention provides a method of separating a photovoltaic strip from a solar cell. The method includes providing a solar cell, placing the front side of the solar cell on a platen such that the backside is facing a laser source, initiating a laser source to output a laser beam having a wavelength from 200 to 600 nanometers and a spot size of 18 to 30 microns, subjecting a portion of the backside to the laser beam at a power level ranging from about 20 Watts to about 35 Watts to cause an ablation to form a scribe region having a depth, width, and a length, the depth being from 40% to 60% of a thickness of the solar cell, the width being between 16 and 35 microns to create a plurality of scribe regions spatially disposed on the backside of the solar cell.
1. A method comprising:
providing a solar cell comprising either a single crystalline silicon material or a polycrystalline solar cell, the solar cell having a backside and a front side and a thickness, the backside having a metal material;
placing the front side of the solar cell on a platen such that the backside is facing a laser source;
initiating a laser source to output a laser beam;
subjecting a portion of the backside to the laser beam at least twice to cause an ablation to form a scribe region having a depth, width, and a length, the depth being from 40% to 60% of the thickness of the solar cell, and the length being equivalent to a length of the solar cell;
removing a vaporized material from a vicinity of the ablation; and
capturing the vaporized material using a vacuum.
2. The method of claim 1 wherein removing the vaporized material comprises subjecting a fluid, using a laminar flow, within the vicinity of the ablation.
3. The method of claim 1 wherein removing the vaporized material comprises delivering a jet of fluid to the vicinity of the ablation.
4. The method of claim 1 wherein the laser beam has a spot size of 18 to 30 microns.
5. The method of claim 4 wherein the laser beam has a wavelength from 200 to 600 nanometers.
6. The method of claim 1 wherein the laser beam has a wavelength in a green portion of the spectrum.
7. The method of claim 1 wherein the laser beam has a wavelength in an ultraviolet (UV) portion of the spectrum.
8. The method of claim 1 wherein the laser source comprises an infrared (IR) laser.
9. The method of claim 1 wherein the scribe region is shaped as a notch as viewed along an end of the scribe region.
10. The method of claim 1 wherein the scribe region is V-shaped.
11. The method of claim 1 wherein the scribe region is a straight line+/−10 microns.
12. The method of claim 1 wherein the thickness is from 170 to 220 microns.
13. The method of claim 1 wherein the length is 156 mm+/−2 mm.
14. The method of claim 1 wherein the depth is between about 65 and 132 microns.
15. The method of claim 1 wherein the width is from about 15% to 40% of the depth.
16. The method of claim 1 wherein the width is from about 7% to 20% of the thickness.
17. The method of claim 1 wherein subjecting the portion of the backside to the laser beam comprises applying the laser beam at a repetition rate of between about 100-300 kHz.
18. The method of claim 17 wherein the repetition rate is between about 100-200 kHz.
19. The method of claim 1 wherein subjecting the portion of the backside to the laser beam is performed at a height varying not more than +/−50 μm.
20. The method of claim 19 wherein the width varies by 5 μm or less along the length.