Why Do Energy Storage Batteries Need UL Certification? A Comprehensive Analysis of UL 1973, UL 9540, and UL 9540A

With the rapid growth of the global clean energy and energy storage market, product safety and compliance have become critical factors for customers selecting solar energy storage batteries. For companies aiming to enter the North American market or seeking international recognition for their projects, UL certification has become an indispensable “passport.” Among these, UL 1973, UL 9540, and UL 9540A are the three most important certification standards in the energy storage industry.

This article provides a detailed analysis of the significance and scope of these three certifications, along with an overview of countries or markets mandating UL certification, to assist customers in making informed decisions during product selection and procurement.

I. UL 1973: Safety Certification for Battery Modules and Systems

UL 1973 primarily targets battery modules and systems, ensuring their safety and reliability across various application scenarios.

Testing Includes: Cell consistency, shortcircuit protection, overcharge/overdischarge protection, cycle life, vibration/shock resistance, and ingress protection rating.

Scope of Application: Stationary energy storage systems, EV auxiliary batteries, rail transit batteries, etc.

Customer Value:

Ensures the safety and reliability of cells and modules, preventing fire and explosion risks.

Gain recognition from power utilities, system integrators, and engineering contractors.

II. UL 9540: WholeSystem Certification for Energy Storage

UL 9540 is the core systemlevel safety standard in the energy storage industry, covering batteries, battery management systems (BMS), inverters, fire protection design, and more.

Testing Scope: Electrical safety, insulation, protection, thermal management, explosionproof design, installation compliance.

Scope of Application: Residential Energy Storage Systems (ESS), Commercial & Industrial Energy Storage (C&I ESS), GridScale Energy Storage.

Customer Value:

 Wholesystem certification enables legal installation and operation in the U.S. and Canadian markets.

 Recognition by fire departments and insurance companies prevents project suspension due to noncompliance.

 Reduces project approval time and minimizes subsequent risk costs.

III. UL 9540A: Battery Thermal Runaway and Fire Testing

UL 9540A is a specialized test for battery thermal runaway propagation, evaluating fire spread risks from the cell level to the battery cabinet and system level.

Testing Scope: Whether a single cell's thermal runaway can trigger a chain reaction in modules, battery cabinets, or even the entire system.

Scope of Application: All energy storage systems requiring indoor/outdoor installation.

Customer Value:

Ensures batteries do not cause largescale fires under extreme conditions.

Complies with NFPA (National Fire Protection Association) fire safety codes.

Achieves insurance underwriting eligibility, preventing project shutdowns or uninsurability.

IV. Which Countries and Customers Require UL Certification?

Markets Mandating UL Certification

United States: All energy storage batteries and systems must comply with UL 1973 and UL 9540; largescale projects additionally require a 9540A report.

Canada: UL certification is similarly mandatory; CSA standards are mutually recognized with UL standards.

Markets Strongly Recommending UL Certification

Mexico and Central/South America: Many utilities and EPC projects require UL certification, particularly for projects exporting to the U.S.

Middle East (e.g., Saudi Arabia, UAE): Governments and utilities commonly reference U.S. standards, often listing UL certification as a bid requirement.

Markets Where UL Certification is a Plus

Europe: Primarily enforces CE/IEC standards, but large multinational EPC or financing projects prefer ULcertified products.

Australia, Japan, South Korea: Locally enforce IEC/JIS/AS standards, but UL certification facilitates entry into international collaborative projects or exports to the U.S.

V. Why recommend clients choose products certified to UL 1973 / 9540 / 9540A?

Greater Safety: Ensures stability and fire performance across the entire chain from battery cells to systems.

Compliance: Meets stringent North American legal regulations and fire safety requirements.

Greater Reliability: Gains recognition from utilities, EPC contractors, and government approval bodies.

Reduced Risk: Facilitates insurance coverage, preventing project shutdowns and financial losses.

Enhanced Value: Supports clients in securing financing, subsidies, and international bidding opportunities.

VI. GSL Energy's UL Certification Solutions

As a professional energy storage battery manufacturer, GSL Energy has multiple products certified under UL 1973, UL 9540, and UL 9540A, covering residential, commercial/industrial, and utilityscale energy storage solutions.

Offers wallmounted batteries, stackable batteries, and highvoltage energy storage systems compliant with North American market standards.

Provides complete certification documentation to accelerate project approvals.

Supports OEM/ODM/OBM customization to meet diverse global customer requirements.

Within the global energy storage industry, UL 1973, UL 9540, and UL 9540A have become essential certifications for the North American market. They also serve as key international benchmarks for evaluating the safety and reliability of energy storage batteries.

Selecting ULcertified products not only ensures greater safety and compliance but also helps customers accelerate market entry, mitigate risks, and enhance investment value.