In this work, various local recombination effects are investigated in crystalline silicon solar cells by using lock-in thermography (LIT) measurements which allow performing a local separation of dark current contributions corresponding to the two-diode model. For this purpose, the evaluation of electroluminescence images is upgraded to the case of injection-level dependent lifetimes. For an understanding of the global current-voltage characteristic simulations on the effect of the distributed series resistance are performed. In the main part of this work, analyses of the influence of cracks and the metallization on industrial solar cells are done. Furthermore, process-induced effects on the recombination in high-efficiency solar cells are characterized. Finally, recombination-active defects are analyzed and the possibilities for investigating grain boundaries by high-resolution LIT measurements are shown.