Minimum warranties on the high voltage battery in EVs start at 8 years/100,000 miles in the US. Some battery warranties go beyond that. Warranty protection isn’t just for failure either, but is based on the maximum charging capacity. Each manufacturer guarantees that a battery will maintain a certain percentage of its original capacity. If the battery capacity dips below the guaranteed minimum within the warranty period, they will replace the battery at no cost. This is simply the warranty though, not the lifespan. EV batteries can easily last 300,000-500,000 miles or more.