Oral-B iO series 7 from dead battery repair.

The Oral-B series 7 is a fantastic tooth brush, I recommend. unfortunately a few months ago it stopped working. The toothbrush stops after a few seconds, showing battery at 0% even if it was connected all night. I open the the tooth brush, took out the battery, reconnected the battery and the tooth brush worked. It worked for months normally. if the problem starts again, I&reopen, remove/reconnect the battery. I feel it would be a waste to trash it and buy a new one.