As the North American energy storage market continues to expand, the safety compliance of stationary Energy Storage Systems (ESS) has drawn increasing attention from regulators, insurers and end users. As a joint U.S.-Canadian national standard, UL 1973:2022 enjoys high industry recognition and serves as a critical compliance threshold for energy storage products entering the U.S. and Canadian markets.

The 3rd edition of ANSI/CA/UL 1973 was officially released on February 25, 2022. The new version includes multiple major updates: newly added test requirements for sodium-ion batteries and metal-air batteries, introduction of Functional Safety assessment, and additional EMC provisions, further raising the safety entry barriers for ESS in North America.

Scope of UL 1973:2022

Applicable Product Categories

• Stationary Energy Storage ApplicationsPV energy storage, wind energy storage, grid-side energy storage, customer-side energy storage, communication base station backup power, UPS uninterruptible power supply, etc.
• Vehicle Auxiliary PowerBattery systems for non-propulsion vehicle applications
• Light Electric Rail (LER)Auxiliary power systems for trams and light rail transit

Non-Applicable Scope

• Traction batteries for road vehicles (governed by UL 2580)
• Small consumer portable batteries (governed by UL 2054 / IEC 62133-2)
• Electric Vehicle Supply Equipment (EVSE) (governed by UL 2594)

Core Test Framework of UL 1973:2022

The standard divides assessment into four major modules: Electrical Safety, Mechanical Safety, Environmental Reliability, and Functional Safety Evaluation, forming a complete safety evaluation matrix for energy storage batteries.

1. Electrical Safety Tests

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2. Mechanical Safety Tests

• Vibration Test: Simulate vibration stress during transportation and operation
• Shock Test: Simulate mechanical impact during handling and installation
• Crush Test: Evaluate safety under external mechanical compression
• Drop Test: Simulate accidental drop scenarios

3. Environmental Reliability Tests

• Temperature Cycling Test: Cycle from -20℃ to +60℃
• Humidity Test: High temperature and high humidity aging (e.g. 85℃/85%RH)
• Salt Spray Test: Corrosion resistance for coastal and harsh environments
• IP Code Test: Dustproof and waterproof rating verification (IP54, IP65, etc.)

4. Major 2022 Updates: Functional Safety & EMC

Functional Safety AssessmentUL 1973:2022 adds formal functional safety evaluation, adopting principles from IEC 61508 / ISO 26262 to audit hardware and software safety functions of the Battery Management System (BMS).

EMC Electromagnetic Compatibility RequirementsThe 2022 edition introduces mandatory EMC testing, ensuring stable operation under electromagnetic interference and preventing unacceptable interference to surrounding equipment.

North American Energy Storage Standard Synergy System

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Testing Institution Service Overview

Guangdong Energy Storage Testing Technology provides professional UL 1973:2022 testing and certification services for energy storage manufacturers. We fully understand North American market access barriers and compliance complexity, offering full technical compliance support:

• Cell-level Testing: Electrical, mechanical and environmental reliability tests per UL 1973:2022
• Module & System Testing: Safety performance evaluation for battery modules and complete ESS
• Functional Safety Support: Assist with BMS safety target definition, FMEA analysis and functional safety documentation
• EMC Testing: Conducted / radiated emission and immunity tests to meet 2022 new EMC requirements
• Integrated North American Certification: One-stop solution combining UL 1973 + UL 9540A + UL 9540 testing and certification

FAQ

Q1: What are the major updates in UL 1973:2022 compared with the old version?

A:

1. Added test requirements for sodium-ion batteries and metal-air batteries;
2. Introduced Functional Safety assessment mechanism;
3. Added mandatory EMC electromagnetic compatibility requirements;
4. Updated evaluation methods for battery system fault conditions.

Q2: What is the difference between UL 1973 and UL 9540? Do ESS need both certifications?

A:UL 1973 focuses on the safety of the battery itself (cell → module → battery system).UL 9540 covers the overall integrated energy storage system including PCS, BMS and thermal management.Stationary ESS entering North America generally need to comply with both standards.

Q3: What does Functional Safety Assessment include? How should manufacturers prepare?

A:It focuses on BMS hardware and software safety functions, including safety target definition, FMEA analysis, and software safety integrity level evaluation. Enterprises shall sort out the BMS safety architecture in advance and prepare FMEA reports and functional safety manuals.

Q4: What items are included in UL 1973:2022 EMC testing?

A:Four core items: conducted emission, radiated emission, conducted immunity and radiated immunity. The new EMC clause is mandatory in the 2022 edition, requiring early EMC design reservation during product development.