IEEE Power & Energy Magazine - November/December 2020 - 91

Predictive monitoring is complementary to and should
not replace safety system designs, which are essential
for real-time mitigation of catastrophic failures.
for Advanced Energy Storage Technologies (NLAB) of the
National Institute of Technology and Evaluation in Japan. This
NLAB Large Chamber is used to test containers up to 53 ft
(16 m) in length under controlled thermal and wind velocity
conditions (the first facility in the world to do so).
The guidelines under development include IEEE Standard P2686, Recommended Practice for Battery Management Systems in Energy Storage Applications (set for balloting
in 2022). This recommended practice includes information
on the design, installation, and configuration of battery management systems (BMSs) in stationary applications. The
document also covers battery management hardware
(e.g., grounding and isolation), software (e.g., algorithms
for optimal control), and configuration. More recently, the
Modular Energy Storage Architecture (MESA) Standards
Alliance, consisting of electric utilities and energy storage technology providers, has worked to encourage the use
of communication standards and advanced interoperability as
well as the reduction of the engineering effort required to integrate an ESS into a utility. MESA is developing two standards:
one that defines the communication between ESS components
and another that defines the communication requirements for
utility-scale ESSs. These standards include parameters for
inverters, meters, general ESSs, BESSs, and Li-ion BESSs
under various operations.

3) Faulty installations: Human error during installation
could have led to system faults, resulting in ESS fires.
4) A lack of ESS integrated control and protection systems:
Gaps in the integration of the BMS and -energy management system (EMS) may have caused the fires.
The conclusions of the investigation raise the following
question: When it comes to the next stage of failure analysis
for ESSs, how can the industry further improve operations to
reduce incidents in the field? Some of the issues noted in the
South Korea investigation were not captured by standards,
and there was no mechanism for identifying and fixing problems or design issues after the installation.
Currently, the industry certifies ESSs based on defined
sets of codes and standards. This certification focuses on the
overall design review of the core ESS, testing for adherence
to standards before shipment, and commissioning once the
unit is installed in the field. Ideally, the certification process
ensures that the overall system design is sound, the factory
testing makes certain that the unit was constructed correctly,
and the commissioning test confirms that there were no faults
created or discovered immediately after the unit was installed
at the site. Nevertheless, gaps remain in maintaining the unit
after installation and identifying potential failures that may
occur in the longer term. In short, there is not much guidance
on what to do on day 2 after a project is completed.

Gaps in the Current Approaches to Safety
Despite the depth of these collective efforts to understand
and mitigate the causes of BESS failure, catastrophic failures
continue to occur in the field. In 2019, South Korea initiated a
study to determine the leading causes of 23 BESS fires that had
occurred since April 2017. The country's Ministry of Industry formed an investigation committee of academics, research
institutions, laboratories, and ESS industry experts. In the initial
cases examined, cells or battery modules were not believed to be
the root cause of the failure. As reported in the press at the time,
the investigation identified four main causes of failure:
1) A lack of battery protective systems for electric shock:
Systems were not able to properly protect dc contactors from the electrical hazards arising from overvoltage or overcurrent.
2) Insufficient management of the operating environment: Most of the installations were in mountainous or
coastal areas. These environments exposed the BESSs
to harsh conditions, including large -t emperature
swings and high humidity, that could damage insulation and cause fires.
november/december 2020

figure 2. An example of a full-scale ESS testing facility, the
National Laboratory for Advanced Energy Storage Technologies' (NLAB) "Large Chamber," operated by the National
Institute of Technology and Evaluation, Japan.
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IEEE Power & Energy Magazine - November/December 2020

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