I know that in a normal battery once the electrons have made their way from the anode to the cathode the battery dies, but rechargeable batteries are able to sort of reset the battery once it’s been put on charge.
Every time I watch a YouTube video on rechargeable batteries all they say is “We do this by forcing the electrons back to the anode” without explaining exactly how that works and its driving me up the goddamn wall.
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Electrical potential energy is stored in the chemicals in the battery waiting to push the electrons around a circuit as soon as the battery is connected and the electrons have somewhere to go.
When the battery is connected, a chemical reaction releases the electrons so they can flow. Once the electrons have flowed through a circuit or device and the voltage that pushed them is no longer there, the battery is dead.
The chemical reaction in a rechargeable battery can be reversed so that the electrons released can be restored to their original place (or very nearly – they don’t last forever) by adding the energy required to push them back to where they were. This is done by applying a reversed voltage to the battery and putting in energy from an external power supply such as a solar panel or mains plug using a charger.
By supplying a voltage from a power source to push the electrons back in the other direction, the chemical reaction is reversed and some energy to move the electrons is put back into the battery and stored in the chemicals, and can be released by reusing the battery.
It’s a little like the way your toilet flushes: potential energy (in that case gravitational rather than electrical) from the water stored in the toilet tank is used to move the waste out of the toilet – so we add more energy by refilling the tank from the water main once the flush is done so we add more potential energy to the system and it’s “recharged” and ready to use again.
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