Top 3 Standards for Lithium Battery Safety Testing
Lithium batteries are among the most commonly used energy storage units in today’s electronic devices. While they present distinct performance advantages in comparison to other battery chemistries, lithium batteries also present distinct safety concerns that must be addressed to ensure safety for end-product users.
For small lithium batteries, there are three major standards for batteries :
- UN/DOT 38.3 – Recommendations on the Transport of Dangerous Goods
- IEC 62133-2:2017 – Safety requirements for portable sealed secondary lithium cells, and for batteries made from them, for use in portable applications – Part 2: Lithium systems
- UL 2054 2nd Edition – Household and Commercial Batteries
Following is a quick overview of each one.
Want to ship a lithium battery almost anywhere in the world by air, vessel, rail, or truck? Unless you want to be extremely restricted in your options for transporting your batteries (ground transport as Class 9 Hazardous Goods), you will need to certify that your batteries have passed UN/DOT 38.3.
UN 38.3 presents a combination of significant environmental, mechanical, and electrical stresses, in sequence (T1-T5):
- T1 – Altitude Simulation (Primary and Secondary Cells and Batteries)
- T2 – Thermal Test (Primary and Secondary Cells and Batteries)
- T3 – Vibration (Primary and Secondary Cells and Batteries)
- T4 – Shock (Primary and Secondary Cells and Batteries)
- T5 – External Short Circuit (Primary and Secondary Cells and Batteries)
- T6 – Impact (Primary and Secondary Cells)
- T7 – Overcharge (Secondary Batteries)
- T8 – Forced Discharge (Primary and Secondary Cells)
Some tests are easier to pass than others. The altitude test is the easiest. The vibration test, on the other hand, is intense and long-running: 3 hours in each of the three cardinal planes. And the T1-T5 sequence typically has a negative cumulative effect.
The complete manual is available following this link : complete manual UN38-3 Rev6
Mandated by many IEC end-device standards, IEC 62133 is the de facto standard for international compliance. UN 38.3 transportation testing (see previous section) is an integral requirement, but does not need to be repeated.
The standard includes four tests:
- 2.2 Molded Case Stress
- 3.2 External Short Circuit
- 3.3 Free Fall
- 3.6 Overcharging of Battery
Compared to the requirements of UN 38.3, these tests are relatively easy to pass.
Compliance with the requirements of UL 2054 is mandated by a number of U.S. end device standards. It is a challenging standard involving roughly double the number of tests found in the UN or IEC requirements:
- 7 electrical tests
- 4 mechanical tests
- 4 battery enclosure tests
- 1 fire exposure test
- 2 environmental tests
With the inclusion of single faults and worst-case operation, the electrical tests are the most challenging. The abusive overcharge test is the most difficult given the overvoltage conditions applied to the faulted pack. Abnormal charge, forced discharge, and two short circuit tests also involve significant risk of failure.
For lithium batteries, UL 2054 defers all component cell level testing to UL 1642.
The future of UL 2054 is cloudy. UL has released the first edition of UL 62133, which is fully harmonized with IEC 62133, 2nd Edition. UL 2054 and UL 62133 essentially compete for the same test space although their requirements are quite different. The timing of UL 62133 adoption is still unfolding, but it is expected to have an impact on the future role of UL 2054 as an important U.S. compliance standard.
Of course CE Marking is important for European market;
The European ‘CE’ certification is a mark that confirms that the product complies with the relevant European directive, this means that the product complies with the essential requirements of the relevant European health, safety and environmental protection legislation. The CE Marking confirms that the product can be placed on the market in any of the European Union and EFTA countries. It certifies that the manufacture assembles the product in accordance with the requirements of the European directive.
In the case of batteries, these must comply with IEC 61000-6-1 & 61000-6-3 standards in order to qualify for this marking. These standards relate to Electromagnetic Compatibility (EMC) Directive.
Which tests apply to which certifications?