Your supplier sent a UN38.3 or IEC 62133 certificate. Here's how to check if it's real, matches your actual cells, and was issued by an accredited lab.
Battery certification fraud is the most common compliance failure in Chinese electronics supply chains. Not outright counterfeiting — more subtle than that. A real certificate from a different cell model. A self-issued test report dressed up as an accredited lab result. An expired certificate passed off as current. You receive a PDF, it looks official, and you have no obvious way to know it's wrong.
This guide is not about what UN38.3 or IEC 62133 requires. It's about what to do when a certificate lands in your inbox.
The three certificates you'll encounter
| Certificate | What it covers | Required for |
|---|---|---|
| UN38.3 | Transport qualification for lithium batteries shipped by air | IATA air freight — every lithium battery shipment by air |
| IEC 62133 / EN 62133 | Product safety for portable sealed secondary lithium cells | CE mark in the EU; EN 62133-2 is the European adoption of IEC 62133-2 |
| UL 62133-1 | US-specific product safety standard | UL mark; tested by accredited US labs (UL, Intertek, MET Labs) |
UN38.3 is purely a transport document — it does not certify that the battery is safe to use in a product. It certifies that the cell survived the 8 transport stress tests required by IATA. IEC 62133 covers product safety. They are separate requirements and a supplier providing only one of them when you need both is a problem.
How to verify a UN38.3 summary document
A valid UN38.3 summary document must contain these 8 items:
- Cell/battery manufacturer and trade name
- Cell/battery model number/designation
- Cell chemistry (e.g., "lithium-ion polymer, LiCoO2 cathode")
- Nominal voltage and capacity (Wh)
- UN number (UN3480 for standalone lithium-ion batteries; UN3481 for cells/batteries in or with equipment)
- Name of testing organization and accreditation number
- Test date(s)
- Pass results for all 8 tests (T1–T8)
The cell model check. The single most common fraud is a supplier attaching a valid certificate for Model A to a shipment of Model B. The cell model on the certificate must exactly match the cell in your purchase order. Ask your supplier for the cell manufacturer's spec sheet and cross-reference the model number character by character. "LP504060" and "LP504060A" are different cells.
Lab accreditation check. For Chinese labs, verify the testing lab's CNAS accreditation number at cnas.org.cn. Search the lab name and confirm their scope includes transport testing of dangerous goods under UN regulations. SGS, Bureau Veritas, Intertek, and TÜV Rheinland all have this scope. A report from an unknown lab with no verifiable CNAS number should be questioned directly before you accept the shipment.
How to verify an IEC 62133 certificate
The IECEE CB Scheme maintains a public database at iecee.org. Navigate to OCS → Certificate of Conformity search. Search by manufacturer name or certificate number (format: CN/[LAB]/[number]/CB).
A valid IEC 62133 certificate appears in this database within days of issue. If your supplier has a certificate that doesn't show in IECEE OCS, ask why — the answer tells you a lot. "The database takes time to update" is not a valid reason after more than two weeks.
EN 62133 note. EN 62133-2:2016 is the EU adoption of IEC 62133-2:2017. Same tests, published by CENELEC. A CE Declaration of Conformity citing EN 62133-2 is valid for EU market, but should be backed by an actual test report from an accredited notified body or accredited lab — the DoC alone is not a test certificate, and any importer can write one.
Red flags in supplier responses
- "We have the certificate but our last customer owns it." Real certificates belong to the cell manufacturer, not the buyer. A certificate is not proprietary to a single purchaser.
- "This is our internal test report." UN38.3 summary documents can be self-generated by the cell manufacturer, but only if testing was done by an accredited lab. Ask for the underlying lab report with the lab's letterhead and accreditation number.
- "It covers a similar cell." Different model = different chemistry = different test required. There is no "close enough" in lithium battery transport testing.
- Certificate date over 3–4 years old for a product in active production. Ask whether the chemistry, BMS, or cell geometry has changed since testing. Reformulations require re-testing.
Quick 5-step verification checklist
When you receive a certificate from a Chinese supplier:
- Cell model match: Certificate cell model = cell model on your PO? (exact match required)
- IEC 62133: Search iecee.org OCS database for the certificate number
- UN38.3: Look up the test lab's CNAS number at cnas.org.cn
- Test date: Flag anything over 4 years old and ask if chemistry has changed
- Pack-level testing: If your product contains a battery pack with BMS, ask specifically whether pack-level testing was done — cell-level testing does not cover the assembled pack
If any of these five checks fails, stop. Do not accept the certificate as-is. Request the original lab report, not just the summary page. If your supplier can't produce it, that tells you what you need to know. Battery certification verification is part of a broader quality system for electronics sourced from China. The electronics quality control guide covers inspection protocols, defect classification, and AQL sampling for hardware production runs.
For complex battery-containing products, a pre-shipment inspection that includes document verification is worth the cost — catching a certification mismatch after the goods are on a vessel is a significantly more expensive problem.
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