Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. An electric vehicle battery (EVB) is a rechargeable battery used in electric vehicles, making them battery electric vehicles (BEVs). Batteries are usually the most expensive component of BEVs, although batteries from old or wrecked electric cars can be bought for battery-to-grid mini-power plants. The cost of battery manufacture is substantial, but increasing returns to scale may serve to lower their cost when BEVs are manufactured on the scale of modern internal combustion vehicles. Since the late 1990s, advances in battery technologies have been driven by skyrocketing demand for laptop computers and mobile phones, with consumer demand for more features, larger, brighter displays, and longer battery time driving research and development in the field. The BEV marketplace has reaped the benefits of these advances.