Photovoltaic

Laser are used in production of solar modules, such as scribing, edge deletion, drilling, etc. Due to their high flexibility in beam shape InnoSlab lasers are tailored tools for different processes.

Scribing ▼

To increase the output voltage the large active surface of thin film solar is portioned by laser selective ablation process. InnoSlab lasers with short pulse length and top-hat beam profile is the most efficient tools for ablation of thin film [11]. Fig. 11 shows example of line scribed by a square top-hat beam. The fundamental (1064nm) and the second harmonic are commonly used for the P1 and P2 and P3, respectively.

Edge deletion ▼

For electrical isolation and hermetic sealing of thin film solar module, the complete layer staple on the edges of glass substrate has to be fully removed. For this kind of edge deletion InnoSlab lasers with short pulse length and rectangular top-hat beam is the most efficient choice, because the deletion process can be realized in a way shot by shot with minimum overlapping and scanning perpendicular to the long edge needs lower scanner speed comparing with square beams. Edge deletion of thin film solar module with rectangular top-hat beam.

Structuring of crystalline Si-wafer-solar ▼

For production of highly efficient solar cells with EWT design one of the important step is structuring of back side for building electrodes. Laser structuring processing is commonly done using laser beams with Gaussian beam profiles in combination with scanning optics. Because of threshold behaviour the maximum of effective energy efficiency for the ablation process is only 36.7% (=1/e) [10]. Single laser pulse only results in a circular ablated spot. A minimum overlap of adjacent spots of a factor 1.21 is necessary to form ablated area. The processing speed is greatly enhanced by replacing the Gaussian profile with a flat-top intensity profile and by replacing the radial symmetric cross section with a rectangular beam cross section. Fig. right shows a microscope image of a finger pattern – generated with a square top-hat beam from InnoSlab laser and with a scanner. With high power InnoSlab laser of square top-hat beam it is possible to pattern a 156mm x 156mm within 2.5sec and so that the requirement for high volume production will be fulfilled