Voltage Relaxation After Load Removal — NMC vs LFP
2 A discharge pulse removed at t = 0. Voltage recovers toward OCV over minutes to hours.
NMC (18650) — OCV = 3.75 V, τ₁ ≈ 30 s, τ₂ ≈ 200 s
LFP — OCV = 3.28 V, τ₁ ≈ 60 s, τ₂ ≈ 600 s
Vertical line = load removed (t = 0)
OCV not reliable until full relaxation (may take >1 hour for LFP)