First, Happy new year to you all.

I designed this small tool to collect the energy from the used battery. They may still have more than 70% energy inside even you can not use them for normal cases. This simple device can rise the small voltage to 5 V which can be collected by a power station. Next time I will tell you how to make a power charger as well. Hope it will help you a little.  Save energy, save the earth, from ourselves now. Keep safe this time.

https://youtu.be/evq0B95o6Go