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The lead-acid battery is the main type of battery used for EVs.
Lead-acid batteries are what people use in their gas powered cars for starting them. The only difference between the two types of batteries is that the EV battery is designed to be discharged to a very low voltage and then charged up again and the gas car battery is designed to be used for a short time only to start motor and then quickly recharged.
Another type of battery that some people use are Nickel-Cadmium (Ni-Cad) batteries. These batteries are very expensive compared to the lead-acid type, but do have a somewhat longer cycle life. They may go up to 2000 recharge cycles vs. the lead-acids 700 recharge cycles.
If you used the gas car battery in the EV you would wear it out in a very short timeframe because they do not like to be discharged. This is called it's cycle life.
Cycle life determines how often you would have to replace your battery string in your EV. Generally 1 cycle is from when the battery is fully charged, to when it is discharged down to 85% of it's charge capability.
If you were to use opportunity charging and plugged in at work, the store, etc., you would actually be helping to extend your batteries life and extending the timeframe of when you would have to replace the batteries in your EV. Batteries like to be fully charged.
To get an idea of this some numbers you might see are 600 charge cycles to 85% DOD (depth of discharge), 800 charge cycles to 50% DOD, 1000 charge cycles to 25% DOD.
So what do these numbers represent ?
Well if your battery pack was rated at 600 charge cycles and you discharged your battery pack to 50% DOD (you only went 30 miles each day out of it's 60 available miles) then recharge your car, and you drove like this all the time, the battery pack would last you something like 4 years. Now if you drove 60 miles (85% DOD) each day and only charged it once per day that same battery pack might last you only 2 years, because your deep discharging it more.
But if you used opportunity charging during that same day you could extend your timeline out and get more available miles from your car.
Your drive pattern might look something like -
drive to work (25 miles) (plug-in for charging) leave for lunch (5 miles) leave work and go to the mall (15 miles) (plug-in for charging) drive to the grocery store (5 miles) drive home (5 miles) go out to dinner (10 miles) (plug-in for charging) go to a movie (5 miles) go home (10 miles) plug in for charging.
This senario would get you 80 miles out of your battery pack and you would not have depleted it's energy any more than if you had driven it 60 miles at one time before plugging it in. Effectively extending the battery life and getting more miles out of the battery pack.