Innovative framework combining cycling and calendar aging models
Aspects of the present disclosure describe a single battery degradation model and methods that considers both CYCLING and CALENDAR aging and useful in both energy management and battery management systems that may employ any of a variety of known battery technologies.
1. An electrical generation, storage, and distribution system comprising:
one or more electrical generation systems including fuel-based generators and renewable generators;
one or more electrical storage systems (batteries) electrically interconnected to the electrical generation systems;
an energy management system (EMS) that monitors the electrical generation, electrical storage, and any electrical loads placed upon the electrical generation, storage, and distribution system, said EMS including a battery degradation model and a computer system including:
a pre-processing unit that takes a set of input data and produces a set of CYCLING data and a set of CALENDAR data from that input date, said CYCLING data including charge and discharge rates, average state of charge, ambient temperature, and watt-hour throughput, said CALENDAR data including state of charge and length of time a battery sits idle; said pre-processing unit further;
a primary-estimation unit that separately estimates both CYCLING and CALENDAR aging separately wherein CYCLING aging determines battery capacity for different watt-hour throughput values while other parameters are kept constant by generating a vector of watt-hour throughput values from zero to a maximum allowed watt-hour throughput with an interval of maximum watt-hour throughput interval; and wherein CALENDAR aging determines battery capacity as a function of accumulated storage time while other parameters are kept constant;
wherein the CYCLING and CALENDAR aging are both determined for a same point in time; and
a post processing unit that determines battery capacity at a given point in time as compared with an original battery capacity according to the following:
C
est
adj
(
i
)
=
C
est
orig
(
i
)
·
C
given
C
orig
where C est adj (i) is an adjusted estimated ith value; C est orig (i) is an original i th estimated value; C given is the battery capacity at a given point in time; and C orig is the capacity of the battery, all in amp-hours (A.h.).