Together with its subsidiary Tecnofimes S.r.l., Roth & Rau develops novel in-line firing furnaces which are, next to the antireflective coating, highly influential in the efficiency of crystalline silicon solar cells. Roth & Rau’s furnaces use ceramic rolls instead of metallic belt as a transportation mechanism for the cells. This avoids any metal contamination.
The rolls are fixed in place with only axial rotation, guaranteeing low wear and tear of components. The heating chamber is separated into different heating zones that are independently controlled. Each of the zones can run different gases. Low power consumption (less than 25% of belt systems) is achieved thanks to the low heat load. There is no active cooling and/or heating required for transportation mechanism outside the processing area. The cooling section can be kept short, without the use of cooling water.
The firing furnace delivers a very accurate and repeatable temperature profile. Its design guarantees a long working life of the ceramic components and the heating system. Roth & Rau’s furnaces guarantee low cost of ownership thanks to low power consumption and no need of water cooling.
The absence of thermal memory effects (no belt), together withzone-controlled IR-lamp heating, rapid ramp-up and ramp-down thermal profiles can be achieved across the different zones. The system can standard accommodate three parallel rows of 156 x 156mm2 cells, which allows for very high capacity of up to more than 6000 cells/hour while maintaining small footprint.