Battery knowledge · Testing methods
Chronoamperometry
Stepping an electrode to a fixed potential and recording how the current decays with time. A diffusion-limited current falls with the inverse square root of time, the Cottrell relation, which yields diffusion coefficients; long holds measure leakage currents from electrolyte oxidation or self-discharge, and a staircase of small steps is PITT.
- Also called
- potentiostatic hold, potential step
- Relationship
- i(t) = n·F·A·c·√(D / (π·t))
Example
Explore the graph
An ideal potential-step experiment gives a decreasing diffusion-limited current.
With n = 1 and area = 1 cm², current at 1 s is 0.1721 mA.
i(t) = nFAc √(D/(πt))
Illustrative model. Planar semi-infinite diffusion, constant D and bulk concentration, fast reaction and no convection or double-layer transient. Starts at 0.1 s because the ideal expression is singular at zero.
Use in Lemonergy
Record specimen, state, instrument, temperature and timing.
This is a reference concept. No executable Lemonergy block has been verified for this term.
References & further reading
Further reading on this topic
These sources provide broader context; they are not presented as citations for every statement in this entry.
- Battery Test Manual For Electric Vehicles, Revision 3
Jon P. Christopherson · Idaho National Laboratory · 2015
Topic background · Performance characterization, pulse resistance/power, life testing and reference performance tests; historical 2015 edition.