Meaning
Quality control monitoring procedures track the open circuit voltage drop of manufactured cells across dedicated rest periods to detect internal micro-short circuits. K-factor logging records the rate of voltage change per unit time, expressed in millivolts per day, during cell aging phases. This process governs manufacturing lot screening, applying during post-formation storage and stopping once cells pass final grading prior to pack integration.
Measurement Protocol
Automated voltage measurement stations record open circuit voltage at precise intervals during factory aging periods. K-factor logging calculates the slope of voltage decay over aging durations ranging from seven to twenty-one days under controlled temperature settings. Precise temperature control remains mandatory because thermal fluctuations induce voltage variations that obscure minor self-discharge anomalies.
Cells demonstrating elevated decay slopes reveal unwanted electronic conduction pathways between positive and negative electrodes, prompting automatic removal from the production stream.
Defect Detection
Internal micro-shorts resulting from conductive metallic contaminants or separator pinholes exhibit elevated voltage drop rates. Early identification prevents defective cells from reaching pack assembly, where micro-shorts cause localized heating and potential thermal runaway.
Yield Optimisation
Production yield analytics utilize voltage decay trends to evaluate process stability in cell manufacturing lines. Consistently low decay metrics across production lots validate separator integrity and electrolyte purity.
