While you can still lease an electric car battery, most are now included in the purchase price of an EV.
In the early days of electric cars, some manufacturers would lease the battery separately, even if you bought the car outright. This was a massive disadvantage for customers as it included mileage caps and extra leasing costs. However, it was seen as necessary while the technology was still developing. Now, electric car batteries last long enough that mileage caps aren't needed.
Leasing a battery means more monthly payments on top of PCP (Personal Contract Purchase) or PCH (Personal Contract Hire) Finance payments.