Every lithium cell that ships by air, sea, road, or rail has to clear UN 38.3. Every cell sold for portable consumer use has to clear IEC 62133-2. Miss either and the shipment stops at customs. Plan for both from week one of a program.
UN 38.3 at a glance
UN 38.3 is transportation-focused. It exists so a cell sitting in a cargo hold at 38,000 feet doesn’t become an emergency. Eight tests, in order:
| # | Test | What it simulates |
|---|---|---|
| T1 | Altitude | Low-pressure cargo hold (11.6 kPa, 6 h) |
| T2 | Thermal cycling | −40 °C ↔ +72 °C, 10 cycles |
| T3 | Vibration | 7 Hz – 200 Hz sinusoidal sweep |
| T4 | Shock | 150 g, 6 ms half-sine, 18 impacts |
| T5 | External short circuit | <0.1 Ω short at 57 °C |
| T6 | Impact / crush | Cylindrical cells: 9.1 kg bar drop; pouch: crush plate |
| T7 | Overcharge | 2× rated voltage, 24 h |
| T8 | Forced discharge | 12 V reverse current, for cells only |
Pass criteria are straightforward: no fire, no explosion, no leakage beyond defined limits, and post-test voltage above 90% of nominal (for non-destructive tests).
IEC 62133-2 at a glance
IEC 62133-2 is the cousin standard for portable-application safety. Where UN 38.3 asks “will this cell survive transport?”, IEC 62133 asks “will this cell survive foreseeable abuse during use?”. The test matrix overlaps but is stricter in places:
- External short circuit (23 °C and 55 °C, cell only)
- Abnormal charging (3× manufacturer-specified current)
- Forced discharge
- Molded-case stress at high ambient (for battery packs)
- Drop (1.0 m, 6 drops per axis orientation)
- Mechanical crush / impact
- Thermal abuse (130 °C, 10 minutes)
How to plan a test campaign
The cheapest and fastest path is to run both standards in parallel at the same accredited lab, on the same sample set. Typical campaign:
- Week 0: Ship 48–64 samples (enough for both test matrices + reserve).
- Weeks 1–3: Lab execution.
- Week 4: Draft reports, response to any observations.
- Week 5–6: Final CB / UN report issued.
Budget: USD 6k–12k for UN 38.3 alone, USD 10k–18k for both together, for a single cell model. A second cell model (e.g. cosmetic colour variant, different BMS) often qualifies as a “family member” with a reduced test set and lower cost.
What usually fails
After years of testing campaigns, the same failures recur:
- T7 overcharge on small pouches without a CID (current interrupt device). If your cell is under 500 mAh and the BMS is external, you almost always need a secondary protection.
- T6 crush on ultra-thin cells — the pouch laminate tears before the cell reaches the deformation threshold.
- T3 vibration on cells with long internal tabs that were not spot-welded with enough redundancy.
None of these are fatal, but each adds 2–3 weeks to the program if discovered late.
What you need as an OEM buyer
- A current UN 38.3 test summary (the “test summary” document, MP-style) for every shipping lot.
- A CB certificate referencing IEC 62133-2 for any cell sold into portable-application markets.
- Country-specific marks where required: KC (Korea), PSE (Japan), BIS (India), BSMI (Taiwan), INMETRO (Brazil).
Ask your cell supplier for the full test reports, not just the certificates — you’ll need them for your own FCC and CE files.