system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why are car batteries already "good enough" that they haven't changed much while all other battery technology has improved?

Car batteries look basically the same in cars from decades ago, but mobile devide batteries are much smaller, stronger etc. So what is it about the standard car battery technology that has stood the test of time?
gpt
Car batteries require a very powerful, but short burst of energy to get the engine started. This is very different of what we expect of other battery use cases: small size and long endurance. In that sense a car battery acts more like a capacitor than a battery. 

Therefore car batteries are still lead-acid based instead of Lithium. The battery in electric vehicles is of course a Lithium one. There has been some improvements to avoid battery failure, but in essense there is little to no need to innovate lead-acid batteries.