Lithium-rich giant stars are rare and their existence challenges our understanding of stellar structure and evolution. We profit from the high-quality sample gathered to search for planets in open clusters with HARPS and UVES, in order to search for Li-rich giants and to identify the Li enrichment mechanisms responsible. We derive stellar parameters for 247 stars belonging to 32 open clusters, with 0.07Ga<ages<3.6Ga. We employed the spectral synthesis technique code FASMA for the abundance analysis of 228 stars from our sample. We also determined ages, distances, and extinction using astrometry and photometry from Gaia and PARSEC isochrones to constrain their evolutionary stage. We have found 14 canonical Li-rich giant stars which have experienced the first dredge-up. This corresponds to 6% of our total sample, which is higher than what is typically found for field stars. The majority of the stars (11/14) are located at the red clump, two lie on the red giant branch, and for one we could not conclude on its evolutionary stage. Apart from the canonical limit, we use the maximum Li abundance of the progenitor stars as a criterion for Li enrichment and find 12 Li enriched stars (5/12 appear in the red clump, 5/12 at the upper red giant branch and two we could not conclude on its evolutionary stage). We find Li enhancement also among eight stars which have passed the first dredge up and show strong Li lines based on the fact that stars at the same evolutionary stage in the same cluster have significantly different Li abundances. Our Li-rich giants are found in various evolutionary stages implying that no unique Li production mechanism is responsible for Li enrichment but rather different intrinsic or external mechanisms can be simultaneously at play.

Cone search capability for table J/A+A/674/A157/tablea1 (Coordinates, V and G magnitudes, and Gaia ID)