Lithium batteries are dangerous goods. This is not optional paperwork but a hard requirement of the international transport rules (IATA for air, IMDG for sea). The three most common buyer accidents are all document-related: missing certificates discovered at the port, a report that covers cells rather than the finished battery you actually bought, or a carrier refusing the shipment at the last minute. Here is how the three documents differ.
1. UN38.3 is a transport-safety test report
UN38.3 refers to section 38.3 of the UN Manual of Tests and Criteria for the transport of dangerous goods. For lithium batteries it specifies eight tests: altitude simulation, thermal cycling, vibration, shock, external short circuit, impact/crush, overcharge and forced discharge. A third-party lab issues the test summary and report once the design passes.
The key point: UN38.3 is applied per design type, not per production batch — the same model and design can reuse the report. That is why the product description on the report must match the battery you actually order.
2. A cell report is not a battery pack report
This is the most common trap. Many suppliers hand over a cell maker's UN38.3 report as if it covered their finished pack. But under the rules a cell and a battery are two different levels: if your finished pack does not match the model described in the report, the carrier or customs may require additional documents or refuse the cargo.
The safe approach: ask for (a) the cell UN38.3 report proving the upstream source is compliant, (b) a UN38.3 report for the finished pack model, or (c) if that does not exist yet, written confirmation from the lab or a scheduled test plan. Treat vague answers as a no.
3. The three documents side by side
| Document | The question it answers | Issued by | Needed when |
|---|---|---|---|
| UN38.3 | Has this battery passed transport-safety testing? | Third-party lab | Air and sea freight, almost always |
| MSDS / SDS | What is this cargo chemically, what are its hazards and how is it handled in an emergency? | Manufacturer (pack or cell maker) | Customs, carrier booking, warehousing |
| Dangerous-goods packing certificate / transport appraisal | Does this packaging meet dangerous-goods transport requirements? | Customs or designated inspection body | When booking as dangerous goods |
4. Air and sea freight follow different rules
Air is the strictest. Standalone lithium-ion batteries (UN3480) face tight quantity limits and many airlines accept pure battery cargo only reluctantly; batteries packed in or with equipment (UN3481) move more easily. Air freight also requires cells to be shipped at no more than 30 percent state of charge.
Sea freight is the workhorse for battery packs. Under the IMDG code the cargo is normally booked as dangerous goods, requiring a packing certificate or transport appraisal, correct labelling and compliant outer packaging. Slower, cheaper and far less restrictive — the normal route for bulk B2B orders.
5. Pre-shipment checklist
- The model description on the UN38.3 report matches your order, word for word
- MSDS is current and issued by the actual manufacturer
- Cartons carry the lithium battery mark, proper shipping name and UN number
- Packing method matches what the certificate describes (quantity, separators, cushioning)
- Confirm with the forwarder early that the route accepts lithium battery cargo — not three days before departure
- Keep your own electronic copy of every document, not only at the supplier
One honest note to close: documents describe a design. A supplier who is loose about capacity or cell grade is often loose about transport paperwork too — so ask about cell sourcing and measured capacity at the same time you ask for certificates.
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