Depends on the battery type and location, and how they are used and charged. Exposure to extreme temps will destroy many batteries (typical limits are 120 F. high to -13 F. low). 100k-150k 'seems' to be the typical battery life, but details on specifics are hard to find. Cost is also highly variable, from a few thousand to $14,000 for Toyota Rav4 EV NiMH batteries. Battery warranty varies, the 2013 Leaf, 5 years/60k miles, the Prius and Volt are 8 years/100k miles. So beyond 60-100k, you foot the battery bill.