Second-Life Battery
A second-life battery is an EV traction battery, pack, module, or cell that is qualified for continued service after its first vehicle application.
How second life works
Second life can mean reuse in another compatible vehicle or repurposing for a different duty, such as stationary energy storage. Repurposing may require a new enclosure, battery-management interface, inverter, cooling system, protection equipment, and application-specific certification.
Qualification matters more than one percentage
There is no universal State of Health threshold at which an EV battery automatically enters second life. Suitability depends on remaining energy and power, cell consistency, electrical isolation, self-discharge, thermal behaviour, damage and fault history, and the demands of the new application. A battery that no longer meets one driver's range needs may still be usable, while a damaged pack with apparently good capacity may be unsuitable.
See State of Health (SoH) for how battery condition is assessed and EV Battery Lifecycle, Repair, Second Life and Recycling for the full path through repair, reuse, repurposing, and material recovery.
Second life extends useful service but does not eliminate the need for eventual recycling.