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UL Certifications for Battery Systems
Rahul Jalthar

UL Certifications for Battery Systems: A Complete Guide

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Battery Energy Storage Systems (BESS) are becoming essential in today’s energy landscape. Whether for renewable integration, grid stability, or backup power, ensuring the safety and reliability of these systems is critical. This is where UL certifications for battery systems play a crucial role.

UL (Underwriters Laboratories) is one of the most trusted global safety certification organizations. Its standards verify that battery energy storage systems meet strict safety, fire prevention, and performance requirements. For project developers, manufacturers, and operators, understanding these certifications is not optional—it’s necessary.

In this guide, we’ll explore key UL standards such as UL 9540, UL 9540A, UL 1973, and others. You’ll also learn how these certifications impact compliance, insurance, and deployment.

At Sunlith Energy, we help businesses navigate energy storage safety and compliance while building reliable battery solutions.

Why UL Certifications Matter for Battery Energy Storage

1. Safety and Risk Mitigation

Battery systems, if not designed properly, can pose fire hazards or thermal runaway risks. UL standards ensure that systems undergo rigorous testing to minimize these risks.

2. Regulatory Approval

Most jurisdictions require UL-certified equipment for permitting. Without it, projects can face delays, redesigns, or rejection.

3. Market Trust and Bankability

Investors, insurers, and end-users trust certified systems. A BESS with UL certifications demonstrates credibility and long-term reliability.

👉 Related Read: Complete Guide to Battery Energy Storage Certification

Key UL Certifications for Battery Systems

UL Certifications for Battery Systems

UL 9540 – Standard for Energy Storage Systems and Equipment

UL 9540 is the primary certification for energy storage systems. It evaluates the safety, performance, and construction of complete systems, not just individual components.

  • Covers batteries, Power Conversion Systems (PCS), control systems, and enclosures.
  • Required for grid-scale, commercial, and residential BESS installations.
  • Ensures systems meet fire safety and electrical safety standards.

Why it matters: Without UL 9540, your BESS may not receive local authority approval.

👉 Learn more about Energy Storage PCS and how it integrates into certified systems.

UL 9540A – Test Method for Evaluating Thermal Runaway Fire Propagation

UL 9540A is not a certification itself but a test method. It assesses how thermal runaway in one cell can propagate through modules, units, and installations.

  • Provides data on fire propagation and suppression.
  • Often required by fire marshals and building authorities.
  • Supports UL 9540 certification by demonstrating safe design.

👉 Explore our article: UL 9540A Test Method Explained

UL 1973 – Batteries for Use in Stationary and Vehicle Auxiliary Power Applications

UL 1973 focuses on individual battery modules and packs used in stationary systems.

  • Tests electrical, mechanical, and environmental safety.
  • Covers BESS, telecom backup, and EV auxiliary batteries.
  • Often a prerequisite before seeking UL 9540 certification.

Example: A lithium-ion module must first pass UL 1973 before being integrated into a UL 9540-certified system.

UL 1741 – Inverters, Converters, Controllers

Since BESS includes PCS (Power Conversion Systems), UL 1741 applies to inverters and related power electronics.

  • Validates PCS for interconnection safety with the grid.
  • Ensures compatibility with renewable energy and microgrids.
  • Critical for hybrid solar + storage projects.

👉 Read our guide: PCS vs Inverter – Key Differences

UL 1974 – Evaluation for Repurposing Batteries

As second-life batteries become more common, UL 1974 helps ensure repurposed cells are safe for reuse.

  • Evaluates used EV or industrial batteries for BESS applications.
  • Supports sustainability by extending battery life.
  • Ensures recycled batteries meet minimum safety standards.

Benefits of UL-Certified Battery Systems

  1. Regulatory Compliance – Smooth project approvals and grid interconnection.
  2. Enhanced Safety – Reduced risk of fire, explosion, and system failure.
  3. Market Acceptance – Easier financing and insurance.
  4. Long-Term Reliability – Certified systems undergo rigorous life-cycle testing.
  5. Future-Proofing – UL standards evolve with technology, ensuring systems stay relevant.

Challenges in Achieving UL Certification

  • Cost and Time: Certification requires extensive testing, which can delay projects.
  • Design Changes: If a component fails testing, redesign may be necessary.
  • Complex Standards: Navigating multiple UL standards can overwhelm new manufacturers.

This is where industry partners like Sunlith Energy provide support—helping companies design systems aligned with certification requirements from day one.

UL Certifications for Battery Systems

How Sunlith Energy Helps with UL-Compliant Solutions

At Sunlith Energy, we ensure that every battery system we design aligns with UL safety and certification standards. Our approach includes:

  • Design Consulting: Guiding OEMs and EPCs on compliance from the design phase.
  • Testing Support: Preparing systems for UL 9540, UL 9540A, and UL 1973 evaluations.
  • End-to-End Solutions: Delivering certified-ready BESS with integrated PCS, battery modules, and fire safety systems.

Whether you’re deploying grid-scale storage, C&I projects, or hybrid solar + storage, our certified solutions meet the highest safety benchmarks.

👉 Learn more about our Battery Energy Storage Systems

FAQs on UL Certifications for Battery Systems

1. What is UL certification for battery systems?

It is a safety and performance evaluation that ensures battery energy storage systems meet global standards for fire safety, electrical reliability, and environmental resilience.

2. Do all BESS need UL 9540 certification?

Yes. For commercial and residential deployment in most regions, UL 9540 is mandatory.

3. What’s the difference between UL 9540 and UL 9540A?

UL 9540 certifies the system, while UL 9540A is a test method used to analyze thermal runaway propagation.

4. How long does certification take?

Depending on system complexity, UL certification can take 6–12 months.

5. Can second-life batteries be certified?

Yes, through UL 1974, which evaluates repurposed batteries for safe use in stationary storage.

Conclusion

UL certifications for battery systems are the foundation of safe, compliant, and bankable energy storage projects. From UL 9540 system-level approvals to UL 9540A fire safety testing and UL 1973 battery-level compliance, these standards ensure that energy storage systems perform reliably under real-world conditions.

As energy storage adoption accelerates, ensuring compliance with UL standards will not just be a regulatory requirement—it will be a competitive advantage.

At Sunlith Energy, we’re committed to helping businesses deploy safe, certified, and future-ready energy storage systems.

EU Regulations for Battery Energy Storage Systems
Rahul Jalthar

EU Regulations for Battery Energy Storage Systems (BESS): What You Need to Know in 2026

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EU Regulations for Battery Energy Storage Systems:Battery Energy Storage Systems (BESS) are at the heart of Europe’s clean energy transition. By storing renewable electricity, they stabilize grids, reduce fossil fuel dependency, and enable smarter energy management. But with great opportunity comes strict regulation.

The European Union (EU) has introduced comprehensive rules to ensure that battery systems are safe, sustainable, and ethically sourced. For manufacturers, developers, and operators, understanding these regulations is critical to avoid penalties and stay competitive.

In this guide, we break down the EU Regulations for Battery Energy Storage Systems, highlight key compliance requirements, and provide a practical roadmap for companies preparing for 2026 and beyond.

Why the EU Is Tightening Battery Regulations

Europe’s ambitious climate goals—cutting greenhouse gas emissions and reaching net-zero by 2050—require a rapid scale-up of renewable energy and storage solutions. BESS plays a central role in integrating solar and wind into the grid.

However, batteries also pose risks:

  • Environmental impact from mining and disposal
  • Fire hazards if improperly managed
  • Supply chain concerns around critical raw materials

That’s why the EU replaced the older Battery Directive (2006/66/EC) with the EU Battery Regulation (2023/1542), introducing stricter sustainability, safety, and transparency rules.

👉 Related Reading: CE for BESS – Complete Guide to Certification

Key EU Regulations Affecting Battery Energy Storage Systems

EU Regulations for Battery Energy Storage Systems

1. The EU Battery Regulation (EU 2023/1542)

This regulation entered into force on February 18, 2024, and will fully replace the previous Battery Directive by August 2025. It applies to all batteries sold in the EU, including industrial batteries used in energy storage systems.

Main requirements include:

  • Substance restrictions: Limits on hazardous materials such as mercury, cadmium, and lead.
  • Labeling & QR codes: Clear labeling of capacity, hazards, and recycling information, along with a scannable QR code.
  • CE marking: Batteries must carry CE certification, showing compliance with EU directives.
  • Battery Passport: From February 2027, all industrial batteries >2 kWh must include a digital “Battery Passport” with details on composition, carbon footprint, and recyclability.
  • Due diligence obligations: Large producers (turnover > €40M) must implement supply chain policies to ensure responsible sourcing.

2. Extended Producer Responsibility (EPR)

The EU applies Extended Producer Responsibility (EPR) to all batteries, including BESS. This means that producers must finance:

  • Collection and recycling programs
  • End-of-life treatment
  • Safe disposal methods

To meet obligations, companies can join Producer Responsibility Organisations (PROs), which handle compliance on their behalf.

This ensures that batteries don’t end up in landfills but are reused or recycled into the supply chain.

3. Clean Energy and Market Integration Rules

BESS isn’t just about hardware—it’s also about market access. The EU’s Clean Energy Package (2019) gives storage systems fairer treatment in electricity markets.

Key highlights:

  • BESS can participate in wholesale, balancing, and capacity markets.
  • Grid operators must treat storage fairly, avoiding double charging.
  • Developers benefit from streamlined permitting under the Net-Zero Industry Act (2024).
  • The Critical Raw Materials Act (2024) introduces stricter monitoring of strategic materials like lithium and cobalt.

Together, these measures aim to create a level playing field for battery operators while ensuring Europe’s independence from risky supply chains.

4. Safety Standards and Best Practices

Safety is a top concern for utility-scale battery projects. In 2025, the European Association for Storage of Energy (EASE) published Guidelines on Safety Best Practices, covering product design, site management, and emergency response.

For compliance, BESS projects must consider:

  • Voltage thresholds: DC ≤ 1500 V, AC ≤ 1000 V.
  • Minimum capacity: Systems above 20 kWh fall under stricter rules.
  • System-level testing: Incorporating IEC and CE standards into project certification.

👉 Related Reading: IEC Certifications for BESS

By following international standards like IEC 62619, IEC 62933, and IEC 61000, developers ensure their systems are both safe and insurable.

EU Regulations for Battery Energy Storage Systems: Compliance Checklist for Stakeholders

Different players in the BESS ecosystem face different obligations under EU regulations.

StakeholderKey Compliance Actions
ManufacturersSubstance restrictions, CE marking, integrate Battery Passport, supply chain audits
ProducersJoin PROs, fund recycling & collection, manage EPR obligations
DevelopersAlign with EASE guidelines, secure CE & IEC certification, follow permitting rules
Utilities/OperatorsEnsure system transparency (SoC, SoH data), integrate grid codes, meet clean energy rules
InvestorsRequire compliance proof before funding, reduce risk through certification checks

EU Regulations for Battery Energy Storage Systems: Why Compliance Matters for BESS Growth

Meeting EU regulations isn’t just about avoiding fines. It also delivers business benefits:

In short, regulatory compliance is now a competitive differentiator in the fast-growing BESS sector.

Conclusion: EU Regulations for Battery Energy Storage Systems Preparing for 2026 and Beyond

The EU has set a high bar for Battery Energy Storage Systems. From CE marking and Battery Passports to EPR obligations and safety guidelines, every stakeholder must act now to prepare for full enforcement in 2025–2027.

For BESS companies, compliance isn’t a box-ticking exercise—it’s the foundation for long-term growth in the European market.

👉 Next Step: Explore our in-depth guides on CE Certification for BESS and IEC Certifications for BESS to strengthen your regulatory strategy.