TITLE:
Ageing Behavior of LiNi0.80 Co0.15Al0.05O2 Cathode Based Lithium Ion Cells—Influence of Phase Transition Processes
AUTHORS:
Christopher Betzin, Holger Wolfschmidt
KEYWORDS:
Cyclic Voltammetry, NCA, Fatigue of LiNCAO, Primary Control Reserve
JOURNAL NAME:
Materials Sciences and Applications,
Vol.9 No.1,
January
24,
2018
ABSTRACT: In this
paper, commercial lithium ion battery cells consisting of
graphite based anode and LiNi0.80Co0.15Al0.05O2 (NCA) oxide based cathode were investigated regarding their aging behavior. The
capacity loss is dependent on the state of charge (SOC) whereas the battery is
operated with partial cycles at defined SOCs. The structural change of the
positive electrode material is identified as dominating aging process.
Especially grid services such as primary control reserve are of economic
interest for battery system operators. In this application, small charge and discharge cycles are the main
operation mode. Considering the operation of single battery storage systems in
a virtual storage power plant, different
states of charges are much more of interest. Thus the
battery aging behavior of lithium ion cells with NCA based cathode material
with respect to cycling at specific state of charge with small depth of
discharge (DOD) is investigated. The results in this paper provide
understanding of small DOD cycling at given SOC behavior which is necessary for
NCA lifetime prediction in this particular case, especially
in virtual storage plant with various storage systems and thus various SOCs for
delivery primary reserve the small DOD behavior which has an important impact on efficiency and economy. It is a key finding,
which aging mechanisms are essential in order to optimize the cell operation
and adapt it to system performance.