Battery material
Research Papers

Mechanistic calendar aging model for lithium-ion batteries

In this work we present a novel mechanistic calendar aging model for a commercial lithium-ion cell with NCA cathode and silicon-graphite anode. The mechanistic calendar aging model is a semi-empirical aging model that is parameterized on component states of health, instead of capacity.

TWAICE / Jun 09, 2023

twaicetech

TWAICE helped me to learn more about: Mechanistic calendar aging model for lithium-ion batteries read article here:

www.twaice.com/research/mechanistic-calendar-aging-model-for-lithium-ion-batteries

#thinktwaice

Mechanistic calendar aging model for lithium-ion batteries

Authors: Alexander Karger, Julius Schmitt, Cedric Kirst, Jan Singer, Leo Wildfeuer, Andreas Jossen

Highlights

  • Mechanistic calendar aging model is parameterized on component states of health
  • Three component states of health are derived from degradation modes
  • Model is parameterized on 627 days of calendar aging at 27 storage conditions
  • Influence of check-up during testing is compensated in a two-step process
  • Check-up compensation increases predicted lifetime by > 150%

In this work we present a novel mechanistic calendar aging model for a commercial lithium-ion cell with NCA cathode and silicon-graphite anode. The mechanistic calendar aging model is a semi-empirical aging model that is parameterized on component states of health, instead of capacity.

Three component states of health are derived from the degradation modes, which are calculated by fitting the electrode potential curves at every check-up measurement. The aging data used for model parameterization spans 672 days of storage at 27 different combinations of ambient temperature (T amb) and state of charge (SOC).

To compensate for the influence of the check-up measurements on cell degradation, the aging data is pre-processed in two steps, considering immediate degradation caused by the check-up cycles and accelerated degradation during subsequent storage. The loss of active anode material is negligible during check-up-compensated calendar aging. For loss of lithium inventory and loss of active cathode material, Tafel and Arrhenius terms are successfully used to model T amb and SOC dependence. The mechanistic calendar aging model predicts the capacity with <1% mean deviation for 7 different storage conditions after 672 days without check-ups. The check-up compensation increases predicted lifetime by >150% for exemplary storage at T amb=60°C and SOC=50%.

Access the paper here.

Related Resources

Battery research and software
Research

Measurement Approaches for Thermal Impedance Spectroscopy of Li-ion Batteries

Battery performance, lifetime and safety are highly dependent on temperature. With the recent high demand for power capabilities, heat management has become increasingly relevant.
TWAICE battery electric vehicle
Research

Evaluation of transmission losses of various battery electric vehicles

Transmission losses in battery electric vehicles have compared to internal combustion engine powertrains a larger share in the total energy consumption and play therefore a major role. In this paper, three simulation models of the Institute of Automotive Engineering are presented.
cell testing in the TWAICE battery research center
Research

Modeling capacity fade of li-ion batteries

Aging models are fundamental tools to optimize the application of lithium-ion batteries. In this work, we show that the CAP-method models capacity fade more accurately when applied to dynamic cyclic aging tests with periodically changing mean state-of-charge, depth-of-discharge, ambient temperature and discharge rates for a commercial NCA cell with a silicon-doped graphite anode.