Protecting Battery Energy Storage Systems
The Electric Power Research Institute (EPRI), a global leader in BESS incident tracking and analysis, has reshaped industry understanding with its 2024 whitepaper, Insights from EPRI’s Battery Energy Storage Systems (BESS) Failure Incident Database, Analysis of Failure Root Cause. Contrary to long-held beliefs that thermal runaway from cell defects is the main culprit in BESS incidents, EPRI found that most failures stem from elsewhere.
According to the aforementioned report, 89% of failures involved controls (battery and energy management systems) or the balance of system (BOS)—everything except the cells and controls. In 86% of cases, the root cause was not a battery manufacturing defect, but poor assembly, flawed design, or operational errors.
In response, EPRI recommends the following key mitigation steps: adherence to codes and standards, careful vetting of suppliers, factory acceptance testing, and environmental monitoring to identify issues (e.g., water ingress, excessive heat or humidity, and equipment overheating) before they escalate.
Based on these findings, the ideal BESS protection strategy follows a three-pronged approach:
- Prevention
Many failures are preceded by subtle environmental shifts—excessive heat, humidity, dust build-up, vibration, or corrosive air. Advanced sensors can monitor these conditions, aiding operators in optimizing performance and preventing failure. - Detection
Even with optimal conditions, failures can develop. Early detection tools include:
– Water ingress sensors to prevent short circuits
– Heat and IR sensors to identify hot spots
– VOC and hydrogen sensors to detect early battery off-gassing
– Smoke and flammable gas detectors to warn of thermal runaway or other combustion - Suppression
When a fire occurs, suppression is critical. EPRI identified water-based systems as a source of leaks which creates new risks. Clean agents are costly and environmentally challenged, and dry chemicals can cause equipment damage and require extensive cleanup.
Stat-X condensed aerosol systems offer a superior solution. They avoid these drawbacks, are easy and affordable to install, and provide effective total-flooding suppression. The aerosol remains suspended to prevent reflash and has been independently tested and proven effective in lithium-ion battery fires.
EPRI’s findings make it clear: true BESS resilience depends on more than just reacting to battery fires—it requires proactive design, integration, and environmental monitoring. A layered strategy of prevention, detection, and suppression offers the most effective path to reducing risk and ensuring long-term system safety.
