The first lithium batteries to appear on the EV scene were small, sealed cells much like flashlight batteries. At approximately 3.3 V per cell and a very low amp-hour capacity, it took about 4,000 of these batteries to power a car. That meant hours of welding connections and too many places for potential connection failure.
To simplify the process, A123 Systems offers lithium nanophosphate batteries in a “developer’s kit” of six cells with connecting tabs attached. The drawback: Intended for “prototyping,” the kits do not come with any technical support.
Other manufacturers are reducing the number of connections by building lithium cells into preconnected batteries. Valence Technologies—the best-known manufacturer of this type of lithium battery—made its batteries available to consumers starting in late 2008. Expect to pay $2,000 for a 12 V, 100 Ah (a 2-hour rate) module with a built-in BMS.
A rising newcomer is the Foxx battery, manufactured by Aten Energy, which can be built up into various-sized units. Expect to pay about $1,250 for a 12 V module.