IEEE Power & Energy Magazine - November/December 2020 - 92

Continuous monitoring of the system post-installation is needed
to facilitate maintenance and ensure that problems are identified
and addressed before they can lead to cascading failures.
Continuous monitoring of the system post-installation is
needed to facilitate maintenance and ensure that problems
are identified and addressed before they can lead to cascading
failures. Systems can be monitored by a BMS, but designs are
not standardized, and owners/operators may not have ready
access to critical information. Also, the inability of management systems to "connect the dots" among large quantities
of data may cause systems to fail. IEEE P2686 may address
some of these gaps. Still, current failure-response mechanisms usually lead to total BESS destruction. ESS hazardmitigation techniques are primarily designed to protect
human safety, which certainly needs to be the focus. These
responses (e.g., water quenching) will often render the system
unrecoverable, making the mitigation just as catastrophic (in
a technical sense) as the initial event. Thus, we advocate the
development of a framework for the predictive maintenance
of operational BESSs as the next critical step in the safe
deployment of ESSs.

Improving Operations Through
Predictive Maintenance
Preventive and predictive maintenance are mature concepts
for operational systems in industry. Operators complete preventive maintenance on a routine or timed schedule (weekly,
monthly, annually, and so forth) based on the average or
expected lifetime statistics for equipment. By contrast, pre-

Oil Pipeline
Corrosion

PV Partial
Shading Faults

Power Plant
Upkeep

Wind Turbine
Gearbox Repair

figure 3. Applications of predictive maintenance for other
systems.
92

ieee power & energy magazine

dictive maintenance is carried out when needed based on the
actual condition of the equipment. Components are monitored
for changes in the operating parameters that may be indicative
of a pending fault, and these changes prompt intervention.
Some organizations have offered general guidance on
preventive maintenance for BESSs. For example, an Energy
Storage Safety 101 presentation during a May 2020 meeting of the California Energy Storage Alliance recommended
semiannual steps such as visually inspecting the overall
system; examining heating, ventilation, and air conditioning (cooling); and checking ESS software control and communications. An annual process similar to commissioning
was also proposed. A 2019 Energy Storage News report on
operations and maintenance noted that the Smarter Network
Storage Project, a 6-MW/10-MWh battery system, receives
a six-month checkup to ensure optimal performance (including identifying battery degradation levels, pushing software
upgrades, and inspecting the power conversion system). In
the same report, a representative from an ESS integrator
noted that much of their maintenance involved software
updates. BMSs implement safety functions and controls that
depend on algorithms, sensor data, and system parameters.
Furthermore, BMSs and inverters must communicate to
coordinate control actions and responses to faults and warnings. Therefore, any software or firmware update glitches
in either of those components can impact the effectiveness
of safety features, leading to potential BMS malfunction
and damage to batteries. Periodic software patching also
ensures that systems are protected from known cybersecurity vulnerabilities.
Although helpful, preventive maintenance may be an
oversimplification of what is required for maintaining complex systems and preventing failures. Here we define a complex system as one with many interacting components where
it is difficult to comprehensively model all of the behaviors
due to the dependencies, relationships, and all other interactions between these components. In complex systems, faults
are less apparent and may not be visually identified or fixed
by a routine procedure. Hence, complex operations for other
systems (see Figure 3) often rely on predictive techniques,
which are yet to be fully explored for BESSs.
Predictive analysis involves understanding how all of
the components in a system fail and then actively monitoring the components for failure criteria. A 2019 report
by GlobalData, "Predictive Maintenance in Power," noted
several successful implementations of this approach in the
utilities sector.
november/december 2020

IEEE Power & Energy Magazine - November/December 2020

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