Universal Power Bank for 220 Volts

What is the use of such a bank, but that it is a "socket in your pocket" and you can connect any charger. Of course, the power to charge the laptop may not be enough, although it all depends on the number of batteries used inside the case. The whole principle of operation is based on connecting a step-up transformer, which increases the voltage to the required 220 volts.

If you liked the idea, you can implement it in a more serious case, and not in cardboard, and increase the number of batteries.