D. J. Friedman, J. M. Olson and Sarah Kurtz National Renewable Energy Laboratory, Golden, CO 80401, USA 8.1 INTRODUCTION The large-scale use of photovoltaics is becoming a reality. The total worldwide solar cell production in 2009 was >10 gigawatts (GW), mostly in the form of flat-plate Si solar cells. This is more than ten times […]

This chapter has reviewed the current state of crystalline silicon solar cells and modules. The main lines defining the structure of the described situation can be summarized as: [64] • Technology diversification. These two challenges are to be faced by solar cell production tech­nology in the next years. Intensive preindustrial research is being conducted and […]

Several organisms, such as the International Electrotechnical Commission (IEC), the Institute of Electrical and Electronic Engineers (IEEE), have designed tests aimed at guaranteeing the quality of PV products [199]. Test procedures have been defined that, if successfully passed by a product, should guarantee the reliability of the PV module. Manufacturers voluntarily submit their products to […]

7.9.1 Lifetime Long lifetime is claimed as one of the main virtues of PV, and some manufacturers currently offer warranty for more than 20 years, with 30-year lifetime being the objective for short-term development. This should mean that for this period of time the module will keep working, i. e. producing electrical power with an […]

The encapsulation affects the optical properties of the cells in several ways. The optical properties of the cells must be optimized, attending to cost and performance after encapsulation. Some effects of encapsulation are [195]: • The refractive index of glass and EVA is similar, around 1.5, between those of air and Si. Encapsulation acts then […]

Due to local shading or failure, one or several solar cells can present a much smaller short-circuit current than the rest of devices in the series string. If the defective cells are forced to pass a current higher than their generation capabilities, they become reverse-biased, even entering the breakdown regime, and sinking power instead of […]

So-called mismatch losses arise when cells with different I – V characteristics are interconnected because of the fewer degrees of freedom left to bias the devices, so that the array output is less than the sum of the powers the individual cells could deliver. The differences come from the unavoidable fabrication spread or from nonuniform […]

7.8.1 Electrical and Thermal Characteristics The voltage of the module is, in principle, the number of series-connected cells times the voltage of the single cell, and the module current the number of paralleled cells times the single-cell current. Whichever the combination is, the module power theoretically equals the power of a single cell times their […]