The battery of your laptop reaches the end of its life, it is no longer powerful enough to ensure a good autonomy of the laptop, here is a clever way to recycle it.
In the battery of a laptop there are lithium batteries. The idea is to recover these batteries to use them as an powerbank for a mobile phone.
For 2 € you can buy a box which contains three battery slots and a printed circuit which manages the supply of batteries and manages the display of the charge level by leds.
It is a small project, very simple to carry out, however make sure that the model of the lithium batteries is compatible with the model of the case. The model of my batteries is ICR18650.