In any case, the bike is alive, currently with 21 cells for about 70 volts of electric power. I tested the bike and the top speed was around 90 km/h with this voltage. I've had it up to 29 cells or 97 volts, which resulted in about 130 km/h top speed. That's about 4.5 km/h per cell or 1.3 km/h per volt.
I have to say the car is really great and range anxiety is gone. Completely. The bigger battery means I can manage my journeys with ease and the ubiquitous Type 2 charging points together with the 22 kW on-board charger of the Zoe means charging is possible almost everywhere, quite often also completely free of charge. So, once again, good times!