Rechargeable Energy Storage System (REESS)
Last modified: Aug 05, 2026
Rechargeable Electrical Energy Storage System (REESS) is the regulatory term for the rechargeable system that supplies electrical energy for propulsion; it can include the battery, enclosure, physical support, thermal management, and electronic controls, while a conventional auxiliary battery is excluded. In an EV, REESS usually means the complete traction-battery system rather than one cell or only its casing; see Post-Crash Systems and Rescue for its post-crash safety boundary.