Ist wahscheinlich der Akku: iRobot Roomba Lithium Batterie

Same problem here, we bough ours in March 2017. The battery stopped charging. Unfortunately, the cleaning did not help.

Hoi, ours is also 2 years and approx. 5 months old and runs without problems, we have a 100 sqm living space that it cleans.
First try to clean the contacts at the bottom of the Roomba as well as at the charging station with some methylated spirits or isopropanol. If that doesn't help, you can find the support link in the Roomba app where you can order spare parts, the battery is easily user-replaceable, there are only 1-2 screws on a cover.

Greetings