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Safety Considerations for Lithium and Lithium-Ion Batteries

Compliance with Applicable Standards Supports the Safety of These Essential Technologies

Lithium and lithium-ion batteries are an integral part of everyday life. They are small, lightweight and, due to a high energy density, offer a long life. Across industries, from medical to consumer electronics, industrial applications to transportation, the small, lightweight energy sources pack quite a punch, making them a popular choice for manufacturers everywhere.

Most lithium batteries used today are safe when designed, manufactured and used properly. However, if they have design defects, are comprised of low-quality materials, are assembled incorrectly, are used or recharged improperly, or become damaged, they can pose a risk. Additionally, because of their high energy density, lithium batteries are susceptible to overheating and can become a fire hazard. For these reasons, there are several safety standards that manufacturers need to apply when developing and using devices incorporating lithium batteries.

UN 38.3

Since lithium batteries can present a fire hazard during transport, they are classified as a dangerous good. To be transported, they must meet provisions laid out in UN 38.3, within the “UN Manual of Tests and Criteria.” Section 38.3 applies to batteries transported on their own or within a device. It applies to all points in the battery’s transportation process, including from sub-suppliers to end-product manufacturer, from manufacturer to distributor, from in or out of the product; in the field, or during product return or within non-original packaging. It is important for the manufacturer to be familiar with these requirements as the use of these batteries becomes more prevalent.

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UN 38.3 has been adopted by regulators and competent authorities around the world, making it a requirement for global market access. The protocol includes identifying/classifying lithium batteries, testing/qualification requirements, design guidance/conditions, and packaging/shipping obligations.

Classification

There are four classifications based on battery type (lithium or lithium-ion) and how they are shipped (alone or in a device):

  • UN 3090 for lithium batteries and UN 3480 for lithium-ion batteries: Apply to cells shipped alone, batteries shipped alone, consignment of cells and batteries, modules or other incomplete battery sub-assemblies, power banks, powerpacks, and batteries shipped in a separate package from the device they power (even if the device and batteries are on the same consignment or shipment).
  • UN 3091 for lithium batteries within a device and UN 3481 for lithium-ion batteries within a device: Apply to devices with batteries installed; devices packed with a battery in the same package, but not installed in the product; up to two spare batteries shipped in the same package as the device (i.e., one installed, two spares).

Testing and Qualification

UN 38.3 requires several tests to ensure the relative safety of the batteries during transport. These tests vary based on the battery and components, as well as the characteristic they are intended to assess:

  • Tests T1-T5, conducted on the same samples for all battery types in sequence:
    • Altitude simulation (Test T1)
    • Thermal properties (Test T2)
    • Vibration (Test T3)
    • Shock (Test T4)
    • External short circuit (Test T5)
  • Test T6, conducted on the primary and secondary cells, evaluates impact and crush
  • Test T7, conducted on secondary batteries, assessing overcharge
  • Test T8, conducted on the primary and secondary cells, assessing forced discharge

Published in November 2019, the 7th Edition of the Manual includes several key changes regarding testing:

  • Integrated batteries: Updated to allow testing of batteries within equipment.
  • Disassembly: Allows for additional test criteria. We recommend any cases that may be considered “borderline” disassembly to be treated as test failures.
  • Rechargeable batteries considerations: Changes to the cycling requirements reducing to 25 charge/discharge cycles prior to test, from 50 previously. Also updates testing tables to reflect these changes.
  • Test summary: Now clearly defines “battery test summary,” as well as the requirement that the test summary “shall be made available.” Additionally, it notes the requirement for the name and title of the signatory as an indication of validity.

Other than clarifying the contents of the test summary, the 7th Edition of the Manual contains no additional changes to the test conditions, criteria or sample requirements as stipulated in the 6th Edition.

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It is important to remember to get or create a test report summary, based on successful completion of UN 38.3 testing. These summaries must be made available from the shipper upon request. Obtain the test reports from cell vendors and subcontractors to complete the test summary for shipments, and maintain the supporting information.

Design Guidance and Conditions

UN regulations also include several sections related to design, which include adherence to the testing and qualification requirements, as well as incorporating a safety venting device or design elements to preclude a violent rupture. Design guidance also includes an effective means of preventing external short circuits, parallel connected cells/cell-strings equipped with a way to prevent dangerous reverse current flow, and the use of a quality management system during manufacturing.

Packaging and Shipping

Recent transport regulation updates include new labels to illustrate the risk of fire associated with the batteries in the package more simply and effectively. Passenger aircraft restrictions have also been updated to prohibit transport of lithium-ion cells/batteries as cargo on passenger planes, requiring that these items be labeled for cargo aircraft only. Lithium-ion batteries shipped alone must be set at or below 30% state of charge (SOC) for cargo air shipment. To meet this requirement, the method used should be documented, as well as how the shipment was verified.

Competent authority approvals may be sought and granted for certain medical device batteries that must be shipped at greater than 30% SOC. This will allow for air shipment of such batteries at higher charge levels.

IEC 62133

IEC 62133 is one of the most important lithium-ion battery standards for global markets. It specifies requirements and tests for the safe operations of portable sealed secondary cells and batteries made from them. There are currently two versions of the standard in effect, IEC 62133 2nd Edition and IEC 62133-2 1st Edition. The names look quite similar, but the versions are different. And the requirements for a battery will vary depending on the market you wish to enter.

It is important to understand the difference between the two standards and how you can determine which is best to use. Some (but not all) of the changes in IEC 62133-2 1st Edition include:

  • Separate nickel (IEC 62133-1) and lithium (IEC 62133-2) chemistries
  • Inclusion of coin cells, if internal AC impedance
    is <3.0 Ohm
  • Inclusion of single fault conditions
  • Changes to cell level requirements
    • External short circuit now performed at +55˚C ambient
    • Thermal abuse hold times have been changed
    • The crush test 10 percent deformation condition has been removed
    • End conditions changed for forced discharge, so they are not only time-based.
  • Adjustments to battery level requirements
    • External short circuit should be performed with single fault condition
    • Different overcharge charge conditions than before
    • Vibration and mechanical shock tests have been added back to standard
  • Incorporation of vibration and mechanical shock testing, based on UN 38.3, with UN 38.3 tests moved to reference Annex E.

The European Union (EU) adopted 62133-2 1st edition in March 2020. Now, all new portable lithium-ion batteries marketed or sold in the EU must comply with these new requirements. Existing batteries and systems generally only need to be recertified if there is a design change or an update to the end-product standard, as batteries are generally considered as components rather than stand-alone end products. Additionally, the U.S. and Canada have adopted ANSI/UL 62133-2 and CSA C22.2 No. 62133-2:20. Transition timelines for enforcement of these versions may vary between testing organizations.

Other countries and markets may adopt the new standard with different timelines. Ultimately, the intended market and end-product will determine which standard to use. When in doubt, partner and consult with experts who can help determine the best path forward.

UL 1642 and UL 2054

UL 1642, “Standard for Lithium Batteries,” is a U.S. standard to ensure the safety of lithium batteries. It covers both rechargeable and non-rechargeable batteries used as a power source in products. In practice, this standard is typically used for certification of component cells, while the resultant batteries are certified according to more application-specific standards.

There are several testing requirements under the standard. For both user- and technician-replaceable batteries, requirements include electrical, mechanical and environmental tests. Specifically, they include assessments for short-circuiting, heating, temperature cycling, forced-discharge, impact, humidity, shock, vibration, drop tests, abnormal changing and altitude simulation. There are also considerations for fire-exposure, flaming particles, projectiles and explosion for user-replaced situations.

UL 2054, “Standard for Safety of Household and Commercial Batteries,” is a performance and safety standard for household and commercial batteries, covering portable rechargeable and non-rechargeable batteries in products. Specifically, the batteries covered in this standard consist of either a single electrochemical cell or two or more connected cells that create electrical energy through a chemical reaction, like lithium and lithium-ion batteries.

UL 2054 is specific to the battery. The safety of the product is covered by its applicable standard. The standard is intended to reduce the risk of fire or explosion when batteries are used in a product and when batteries are removed to be transported, stored or discarded. It includes testing requirements for performance, electrical considerations, temperature, mechanical assessments, battery enclosure and pack evaluations, and environmental tests.

Both UL 1642 and UL 2054 have marking requirements related to warnings about risk of fire, explosion and burns, and require the inclusion of instructions not to recharge, disassemble, crush or heat above certain points or to incinerate. The warning statements should also include instructions on disposal and instructions to call physicians or poison control if ingested. Products should also be marked regarding the use of lithium batteries and their risk, and instructions should include guidance on replacing and disposing of batteries.

Conclusion

With a growing prevalence in multiple industries, lithium batteries play an important role in the design and manufacture of products that fit consumer demands. The very properties that make them desirable—potency, portability, size—present risks and hazards that any manufacturer must address. It is important to familiarize yourself with the applicable standards, their requirements and needs. Knowledgeable teams and partners can make a huge difference in product success, global market access, building brands and ensuring safety.

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