Safety precautions for battery energy storage systems in communication base stations

Here, we summarize various aspects and present mitigation strategies tailored to stationary BESS. Although some residual risks always present with Li-io batteries, BESS can be made safe by applying design principles, safety measures, protection, and appropriate components.

In addition to NYSERDA's BESS Guidebook, ESA issued the U.S. Energy Storage Operational Safety Guidelines in December 2019 to provide the BESS industry with a guide to current codes and standards applicable to BESS and provide additional guidelines to plan for and mitigate potential operational hazards.

However, the DNV GL report concluded that the most commonly relied-upon standards for battery safety are insufficient to address the threat of thermal runaway (described herein) and explosion. The report recommends additional steps that should be taken, and these are included in the summary below.

This document considers the BMS to be a functionally distinct component of a battery energy storage system (BESS) that includes active functions necessary to protect the battery from modes of operation that could impact its safety or longevity.

Some areas worth addressing include better tests for module-level propagation (propagation is still occasionally observed in packs approved to the standard), the impact of aging on battery safety, and the ignition of vent gases to assess the fire resistance of the system.

Research efforts should be invested in developing next-generation batteries with improved safety, such as solid-state batteries. Different fail-safe designs, e.g., safety vents, thermal fuses, current interrupt device (CID), and positive temperature coefficient (PTC) protection, can be implemented.