Addressing the Safety of Energy Storage Systems

14 Apr 2020

A Look at ANSI/CAN/UL 9540: 2020

ANSI/CAN/UL 9540 is the safety standard for energy storage systems (ESS) and equipment. It addresses the safety of ESS intended to store energy from grid, renewable, or other power sources and provide electrical or other types of energy to loads or power conversion equipment. The standard's goal is to ensure that electrical, electro-chemical, mechanical, and thermal ESS operate at an optimal level of safety for both residential and industrial energy users.

Equipment within the scope of ANSI/UL 9540 may include equipment for charging, discharging, protection, communication, containment, and controlling the system environment, such as:

• Standalone ESS that provide energy for local loads
• ESS that operate in parallel with electric power systems
• ESS used in utility-interactive applications in compliance with ANSI/ UL 1741, IEEE 1547, and IEEE 1547.1
• Other ESS applications intended to provide grid support functionality

All modules within an ESS are required to be certified to applicable ANSI/UL and CAN/CSA standards. This includes inverters, batteries, and battery systems.  Evaluation of the critical safety functions and control systems of ESS is included in this standard. The standard may include the following core-level assessments:

• Electrical Tests
• Normal Operations
• Dielectric Voltage Withstand
• Impulse
• Equipment Grounding & Bonding
• Insulation Resistance
• Electromagnetic Immunity Tests
• Mechanical Evaluations
• Containment of moving parts:
• Overspeed qualification
• Faulted securement qualification
• Blocked shaft qualification
• Mechanical failure qualification
• Leakage
• Strength
• General
• Hydrostatic strength
• Pneumatic strength
• Large-scale Fire Testing, per UL 9540A
• Manufacturing & Production Tests
• Dielectric Voltage Withstand
• Grounding & Bonding System Check
• Maximum Abnormal Operating Speed
• Special Environment Installation Assessments
• General
• Outdoor installation subject to moisture exposure
• Outdoor installation near marine environments
• Installation in seismic environments

Testing will be conducted on the ESS system level and some tests may be waived if a similar evaluation has already been conducted under the specific technology standard. Manufacturers should consider a holistic quality assessment and customized compliance plan. This will help to ensure that an ESS is ready for the North American market and others. 

For more information on UL 9540, download our complimentary fact sheet.