Vehicle batteries have an excellent recycling record that will get even better with plug-in vehicles. Every car in the world has a lead-acid battery. Even with its low value as scrap, the national recycling rate for lead-acid batteries is about 98 percent. Plug-in vehicles mostly use lithium ion, which is much more valuable than lead. Their inherent value will ensure that they are recycled. Some car makers are exploring “second-life” applications for used EV batteries as well including adding them to a house hold solar system.
Now that EV's have been around for while manufacturers are learning the batteries last longer than they expected.
For more information: https://www.leadingthecharge.org.nz/what_happens_to_old_ev_batteries