The battery is a key component in Plug-in Electric Vehicles (PEVs) whose degradation should be considered in
vehicle modeling and if the battery pack is to be used in a Vehicle to Grid (V2G) smart grid studies. Several
researchers have proposed different methodologies for PEV batteries degradation modeling from various
aspects. Most of the battery degradation literature consists of empirical-based studies with results extracted
from experimental tests in laboratories. As such, the results have been presented in non-formulated forms and
are of less effectiveness for smart grid researchers. Furthermore, the impact of battery degradation in V2G smart
grid have not been examined in smart grid studies. This paper reviews and compares different battery
technologies focusing on Lithium-ion batteries which dominant in today and future vehicle applications. After
that the most prominent degradation models are assessed, the effects of degradation factors on battery
performance are examined. The literature shows that the degradation causes can be categorized into two groups
namely calendar ageing and cycling ageing. Generally, the calendar ageing is influenced by temperature, time,
and state of charge, while the cycling ageing is influenced by cycle number, charge rate and depth of discharge.
Finally, in this work a conceptual framework for battery degradation modeling is proposed that can be easily
used in smart grid studies, without necessarily requiring a detailed understanding of fundamental electrochemical
processes. The proposed framework considers not only the battery degradation modeling, but also that
of other related components in a smart grid.