how do rechargeable batteries work?
In: Technology
Batteries are chemical reactions. Some chemical reactions are one way. Once the chemicals have reacted they cant revert to their previous form. Some reactions move both ways. Take two chemicals and put them together and they react and release energy. Then put energy into them and the chemicals split apart into their previous form.
Non-rechargeable batteries, such as alkaline, are a one way reaction.
Rechargeable batteries, such as lithium ion, nickel metal hydride or lead acid, are a two way reaction.
This video does a pretty good job of explaining and showing what’s going on: [https://youtu.be/Eu88Qv6HuAQ](https://youtu.be/Eu88Qv6HuAQ)
In the simplest of terms, it’s basically a chemical reaction that creates an electric current, but that when you introduce a current that runs in the opposite way, reverses the reaction and allows it to start over again.
The discharge reaction is forced to go in reverse.
For lithium-ion batteries, the most common consumer and automotive battery in use (other than automotive lead acid, perhaps), lithium ions and electrons move from the anode (graphite) to the cathode (metal oxide material) during discharge. The lithium ions move through the battery, through the electrolyte, across the separator. electrons move through the external circuit and power the device.
During recharge, the opposite happens. electrons and lithium ions flow from the cathode to the anode. This takes provided energy (i.e. from a charger) b/c the electrodes are shifting from a lower energy state (voltage) to a higher one.
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