UL9540A is a safety standard specifically for energy storage systems (Energy Storage Systems,ESS), issued by the American Safety Laboratory (Underwriters Laboratories,UL). The standard aims to ensure that the energy storage system has a high degree of safety and reliability under various operating conditions, so as to prevent the occurrence of fire and other safety incidents.

1. UL9540A Standards Overview

UL9540A is a test standard specifically for the evaluation of thermal runaway spread of battery energy storage systems. By simulating the thermal runaway of the battery, the safety performance of the energy storage system is evaluated when the thermal runaway occurs. The standard not only focuses on the safety of the battery itself, but also covers the integrated safety of battery management systems (BMS), power electronics, system control and the entire energy storage system.

2. UL9540A main test items

UL9540A standard includes multiple levels of testing to ensure the overall safety of energy storage systems:

cell-level test: the cell is heated in a constant-volume combustion bomb and triggers thermal runaway, and the gas composition of thermal runaway is analyzed by gas chromatography and other instruments to evaluate its explosion limit, explosion pressure and combustion rate, so as to issue a comprehensive risk analysis report of the cell.

Module level test: heat the cell in the module and trigger thermal runaway, observe whether thermal runaway spreads to other cells, and comprehensively analyze the gas composition released by the module after thermal runaway, such as hydrogen content, total hydrocarbon gas content, etc., to evaluate the degree of thermal runaway spread and overall risk of the module.

Cabinet-level testing: Modules installed in battery clusters are tested to evaluate the spread of thermal runaway in larger systems and the safety performance of the overall system.

Installation level testing: Evaluate the effectiveness of sprinkler fire protection and fire protection systems installed according to code requirements to ensure that they can respond quickly and control fires in emergency situations such as thermal runaway.

• thermal runaway test

• battery exhaust composition test

• exhaust gas composition of flow battery systems

• battery level detection

• performance Unit Level Test

• flow battery performance thermal runaway measurement test

• indoor floor mounted BESS units

• outdoor ground installation

• indoor wall-mounted device

• outdoor wall-mounted device

• roof and open garage installation

• effectiveness of Sprinkler

• effectiveness of fire plan

• effectiveness of fire protection plan