I find little information published about the lifespan of a battery pack. Today’s IC engines easily last for 10 years or 150,000 mi., frequently longer. I've seen no comparable information for battery packs or what the rate of decline in charge acceptance is over time. If that lifespan is considerably less than that of an IC engine, that price difference would have to be significant to be economic.

Eoin Treacy's view

Thank you for this question which may be of interest to other subscribers. The cost of electric vehicle batteries has been trending lower and is likely to continue to do so as global manufacturing capacity scales up. However, as you highlight lithium batteries suffer from losing degradation over time and with repeated recharging and that represents an issue for consumers. Here is a section from ez-ev.com:

Electric cars run on lithium-ion batteries that are drained and recharged repeatedly, which causes natural degradation of the battery, leading to range loss over time. Most estimates have projected that a typical lithium-ion electric battery car can be driven about 100,000 and maintain a good driving range. But if you realize you are needing to recharge your battery too often, you may want to take it in and see whether it needs to be replaced.

Electric Car Battery Warranties
All of the top-selling electric vehicles come with battery warranties. While electric car batteries do lose capacity over time, it does not happen as fast as the average electric consumer device, which has a 1-4 year expected battery life. Most car companies will offer a warranty based on a number of years from purchase, or the number of miles driven, whichever is reached first. If within the warranty period, the car’s battery is unable to charge above a certain capacity, the battery can be replaced. Here are a few examples of today’s popular EV battery warranties:

That suggests to me that if one is thinking about buying an electric vehicle it is much smarter to lease since one can avoid the cost of replacing batteries while availing of new technology as it becomes available. That point is also highlighted by the fact that electric cars like the Nissan Leaf and Chevrolet Volt have among the steepest depreciation profiles.

One of the primary business models being explored by car manufacturers, is to redeploy older batteries that are no longer fit for transportation, into household and industrial use. Nissan in particular has been actively pursuing this route.