Quantifying Galvanic Corrosion Kinetics across Battery Pack Busbar Terminations
Galvanic corrosion kinetics at battery busbar joints depend on potential offsets, area ratios, and moisture film thickness, requiring controlled plating barriers.
Peck Model
Meaning
A reliability prediction equation calculates the acceleration factor for components exposed to humidity and temperature. Implementation of the peck model allows test engineers to estimate the service life of a battery management system based on accelerated stress data. The formula relates the time to failure to the relative humidity and the absolute temperature of the environment.
It is typically applied to non hermetic electronic packages and moisture sensitive sensors.
Mathematical Variable
Activation energy and the humidity exponent serve as the primary constants that define the reaction rate. Because the peck model uses an exponential relationship for temperature, small increases in thermal stress lead to large reductions in expected life. The humidity component uses a power law to account for the ingress of water vapor.
Acceleration Factor
Ratio between the life in the field and the life under test conditions provides the necessary scaling for quality assurance. Using the peck model identifies how many hours of high temperature storage equal a year of operation in a humid tropical climate. This calculation guides the duration of the highly accelerated stress test.
Lifetime Estimate
Failure distributions help in predicting the percentage of the population that will survive the warranty period. When the peck model suggests a high risk of moisture related failure, design changes such as conformal coating are introduced. Validation occurs by comparing the predicted outcomes with historical field return data.
The model stops being accurate if the failure mechanism changes at higher stress levels.