How do car batteries work? --- Ike, Charlotte, N.C.
Marshall Brain answered:
A car battery is based on lead-acid battery technology. This technology has been around for decades, it is relatively inexpensive, it is reliable even in the harsh environment of a car (big temperature swings, lots of vibration, etc.), and a car battery will typically last three or four years before wearing out. Overall, that's a great set of characteristics compared to other battery technologies.
The article How Batteries Work offers this description of the chemical reaction that takes place in a car battery:
Here's how lead-acid batteries are made, along with a look inside a lead-acid battery:
What happens to all the car batteries after they wear out? It turns out that, because of the unique properties of lead, they are relatively easy to recycle, as shown here: