Calendar Aging of Li-Ion Cells—Experimental Investigation and Empirical Correlation

The lifetime of the battery significantly influences acceptance electric vehicles. Calendar aging contributes to limited operating lithium-ion batteries. Therefore, its consideration in addition cyclical is essential understand degradation. This study consequently examines same graphite/NCA pouch cell that was subject previously published cyclic tests. cells were aged at different temperatures and states charge. self-discharge continuously monitored, after each storage period, remaining capacity impedance measured. focus this publication on correlation measurements. An obtained valid for a wide range results show an accelerated fade rise with increasing temperature, following law Arrhenius. However, data do also indicate there no path dependency, i.e., earlier periods temperature levels not affect present degradation rate. A large impact state charge 100% evident, whereas influence small below 80%. Instead commonly applied square root time function, our are excellent agreement exponential function.