Acculon Energy

Battery Safety 101: The Importance of UL Standards for Manufacturers and Consumers

Join us this week as we delve into UL safety standards to understand why a product safety stamp of approval from a National Recognized Test Laboratory (NTRL) is so important for both manufacturers and consumers alike!

Contact: Betsy Barry
Communication Manager

What is the UL stamp of approval and why is it important?

Underwriters Laboratories (UL) is a global safety certification company. UL is responsible for crafting safety standards across a range of consumer products, particularly those incorporating electrical components. Established in 1894 by electrical inspector William Henry Merrill Jr., the company originated from a growing awareness of fire risks associated with increased domestic electricity usage. In response to this increased awareness, Merrill opened a laboratory to delve into fire and electrical safety, ultimately developing safety standards as a result.

While its origins lie in electrical safety standards, UL’s scope has expanded beyond, encompassing areas such as water quality, food safety, hazardous materials, performance testing, sustainability, and safety and compliance education. With a dedicated research division continuously exploring safe practices for various products and materials, UL holds the distinction of being one of the select standards labs in the United States authorized by OSHA for safety testing.

Over time, UL has evolved into a global entity with 64 laboratories collaborating with clients from more than a hundred nations. Many manufacturers choose to seek approval from UL, as having a UL mark on your product offers credibility in quality and safety and can help with the marketing of your products.

Perhaps even more importantly, UL standards have become a focal point in the realm of lithium battery system safety in the realm of policy and public discourse. Growing public safety concerns over fire hazards associated with e-bikes and e-scooters have prompted several local governments and municipalities to pass laws requiring that these products be certified to UL standards as a condition of being sold and operated in said localities. In the case of micromobility products like e-bikes and e-scooters, UL has responded to growing concerns by updating the standard that applies to these products: UL 2271.

To date, a high percentage of LEV products on the market are not in compliance with the newly minted 3rd edition of UL 2271, which even further puts the spotlight on the safety standard as the bar that the applications must meet to quell safety concerns surrounding the battery systems in these products has been raised. 

There are different UL stamps that relate to product safety certification from Underwriters Laboratories. While they are sometimes used interchangeably, there is a subtle difference in their meanings–a difference that should be understood by both manufacturers and customers.

UL Listed:

When a product is UL-listed, it means that the product has been tested and evaluated by UL to meet specific safety standards. UL has determined that the product complies with these standards, and the product is then included on the UL List, which is a database of certified products.

Being UL-listed involves thorough testing and examination of the product’s design, construction, and performance. UL listing is regarded as a mark of safety and compliance with recognized standards.

UL Classified:

In addition to a product being UL listed, there is also the status of UL Classified. These designations differ significantly. Classified products undergo evaluation for specific attributes, a narrow spectrum of risks, or their suitability under restricted circumstances. When a product receives UL Classification, it indicates that its testing aligns with specific criteria for a single test, yielding a documented outcome. However, this classification does not encompass the entirety of other tests that may be included in a Standard (such as UL 2271, for example).

Whether you’re an OEM developing a battery pack for off-road equipment or a consumer purchasing an e-bike, it’s important to understand the UL safety standards that govern the design & development of the energy storage system that powers your industrial or commercial application.

UL Recognized:

UL Recognized products usually consist of parts or components designed to adhere to specific industry standards. These components may be partially assembled or possess limited functionality, as they’re meant to be integrated into larger products or systems. UL Recognition primarily targets smaller-scale parts and components, in contrast to UL-listed devices and machinery. 

The UL Recognized designation is often simpler to achieve compared to UL Listed, as manufacturers have the flexibility to select specific certified components within a broader system. 

UL Certified:

When a product is UL certified, it means that UL has not only tested and evaluated the product but the manufacturer’s production processes and facilities have also been audited and found to meet UL’s quality and safety requirements consistently. This is a quarterly audit by the UL field office to ensure the UL-certified product is being built with the critical components listed in the Construction Data Report (CDR). This audit also ensures that 1) the product that is provided to the consumer is identical to the product that underwent the UL testing and 2) the manufacturing process and end-of-line testing are being performed with adequate records maintained for compliance.

UL certification goes beyond the product itself and extends to the manufacturing processes. It assures that the product will continue to meet safety standards throughout its production life.


While stamps like “UL listed” and “UL certified” indicate that a product has undergone testing by UL and meets safety standards, it is important to understand the differences, especially when products can easily be marketed as “complying with UL standards,” when in reality, they have not undergone the rigorous testing processes required by UL at an NTRL.  The key takeaway is that both design and production aspects are considered in the UL testing process and when customers see the UL mark, they can be assured that the battery operating their e-bike has undergone stringent and comprehensive scientific testing to prioritize public safety. The proof is in the signature UL mark, which extends well beyond a manufacturer’s message of safety or compliance.