Climate & Environment
State of Health (SOH)
Definition
State of health is a measure of a battery's condition compared to its original specifications, typically expressed as the percentage of rated capacity it still retains (with internal resistance a common supplementary indicator). SOH declines with cycling, age, temperature and charging behaviour; electric vehicle batteries are commonly considered at end of automotive life around 70–80% SOH, at which point they may serve years longer in less demanding stationary applications.
References
Source imported for editorial provenance.
This reference provides supporting context for how “State of Health (SOH)” is defined and used.
Overview
How it is used
The metric structures EV battery warranties, second-life battery markets, battery passport reporting and recycling logistics.
Why it matters
SOH turns a battery from a black box into an asset with a knowable future — the foundation of circular battery value chains.