Thermal runaway in home battery systems has long been a subject of public concern. It is the phenomenon where the battery cell enters an uncontrollable, self-heating state and potentially causes fire or explosions.

In fact, at least 60 residential ESS fire events had been documented globally as of late 2023 by IAFF.There were 543 battery fire incidents in 2024 in South Korea alone, according to South Korea’s National Fire Agency.These events put lives and property at direct risk.

For distributors and installers, a thermal runaway event can also damage reputation and lead to lost contracts.

With that in mind, it becomes essential to know which brands offer credible thermal runaway protection when selecting a partner. The short answer? WHES.

• Why Passive Protection Alone Isn’t Enough

Before getting to what WHES does, it is worth understanding what effective thermal runaway protection should look like.

Most residential ESS systems on the market today incorporate passive protection measures. This typically involves fire-resistant materials, metal enclosures for module separation, and other inherent safety features designed to contain and limit thermal runaway.

These protective measures are necessary，but they are not enough.The best residential ESS should detect and report thermal runaway early and suppress it effectively.

• WHES Approaches Active Protection against Thermal Runaway

As a Tier 1 global energy storage solution provider with over 800 on-site projects across 50+ countries and regions, we at WHES integrate active protection to fight against thermal runaways.

• ECOS Smart Management Platform

Our ECOS smart management platform is an AI-driven system designed to monitor battery status in real-time. It continuously calculates battery state of health (SOH) and detects abnormal fluctuations in battery behavior. When anomalies are detected, the system triggers an alarm through ECOS for overtemperature and other fault conditions.

In other words, ECOS leverages real-time data and AI capabilities to actively provide early warning of thermal runaway risks.

This early-warning capability has a value.When a system delivers timely warnings, it gives customers the chance to take swift action and suppress thermal runaway before escalation, avoiding catastrophic consequences.

• Built-In Fire Suppression System

WHES residential energy storage systems also incorporate a built-in aerosol fire suppression system (FSS) at the battery module level for active protection.

When a thermal runaway event is detected in real-time, the built-in FSS automatically activates, and the released aerosol agent neutralizes flammable gases and suppresses thermal runaway within 15 seconds.

This second-level speed matters: at the temperatures and propagation rates typical of lithium-ion thermal events, every second of delay raises the risk of full-system involvement.

• Third-Party Verification

Our residential energy storage systems and battery modules are backed by a comprehensive set of third-party certifications.

UL 9540A is widely recognized as one of the industry’s most rigorous standards for evaluating thermal runaway fire propagation in battery energy storage systems.

For the US and Canadian markets, our PP-T1, PP-S2, and battery boxes comply with UL 9540A testing at both the system level and battery module level.

For other international markets, they meet UL 9540A testing requirements at the battery cell level.

Additionally, the PP-T1, PP-S2, and battery boxes holds UN 38.3, IEC 62619, IEC 61000, IEC 62040, IEC 63056, UL 1973, and FCC Part 15 (Class B) certifications — covering transport safety, electrochemical performance, electromagnetic compatibility, and electrical safety across major global markets.

For distributors, this breadth of certification is more than a compliance checklist. It means the products you carry have been independently verified to perform safely across a wide range of conditions and markets, reducing the technical and regulatory risk on your end.

• WHES Is the Right Partner for the Long Term

For distributors who carry their reputation into every installation they make, thermal runaway protection should go beyond basic passive safety design. The ideal residential ESS should be capable of detecting abnormalities early, issuing timely warnings, and helping limit escalation if a thermal event occurs.

That is the approach WHES takes. Through AI-driven early warning via the ECOS smart management platform, built-in aerosol fire suppression, modular safety design, and extensive third-party testing, WHES provides a multi-layered safety strategy for residential energy storage applications.