TY  - JOUR
AU  - Lewerenz, Meinert
AU  - Münnix, Jens
AU  - Schmalstieg, Johannes
AU  - Käbitz, Stefan
AU  - Knips, Marcus
AU  - Sauer, Dirk Uwe
TI  - Systematic aging of commercial LiFePO4|Graphite cylindrical cells including a theory explaining rise of capacity during aging
JO  - Journal of power sources
VL  - 345
SN  - 0378-7753
CY  - New York, NY [u.a.]
PB  - Elsevier
M1  - FZJ-2017-03828
SP  - 254 - 263
PY  - 2017
AB  - The contribution introduces a new theory explaining the capacity increase that is often observed in early stages of life of lithium-ion batteries. This reversible and SOC-depending capacity rise is explained by the passive electrode effect in this work. The theory assumes a slow, compensating flow of active lithium between the passive and the active part of the anode, where the passive part represents the geometric excess anode with respect to the cathode. The theory is validated using a systematic test of 50 cylindrical 8 Ah LiFePO4|Graphite battery cells analyzed during cyclic and calendaric aging. The cyclic aging has been performed symmetrically at 40 °C cell temperature, varying current rates and DODs. The calendar aging is executed at three temperatures and up to four SOCs. The aging is dominated by capacity fade while the increase of internal resistance is hardly influenced. Surprisingly shallow cycling between 45 and 55% SOC shows stronger aging than aging at higher DOD and tests at 4 C exhibit less aging than aging at lower C-rates. Aging mechanisms at 60 °C seem to deviate from those at 40 °C or lower.The data of this aging matrix is used for further destructive and non-destructive characterization in future contributions.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000397355500028
DO  - DOI:10.1016/j.jpowsour.2017.01.133
UR  - https://juser.fz-juelich.de/record/830255
ER  -