Lithium cells and batteries are dangerous goods. Not dangerous in the “explodes in your warehouse” sense, but dangerous in the regulatory sense: they move under IATA Dangerous Goods Regulations (DGR) for air, IMO IMDG code for sea, and ADR for road in the EU. Get the paperwork wrong and the shipment stops at origin.

The three UN numbers that matter

  • UN 3480 — lithium-ion cells or batteries shipped on their own.
  • UN 3481 — lithium-ion cells or batteries packed with or contained in equipment.
  • UN 3090 / UN 3091 — lithium-metal cells (primary), equivalent split.

Which one applies determines the packing instruction (PI 965–970 for lithium-ion, PI 968–970 for lithium-metal). Quick rule of thumb: cells alone in a box = UN 3480; device with battery in the same retail package = UN 3481.

State-of-charge caps for air freight

Since 2016, lithium-ion cells shipped as cargo on passenger or cargo aircraft cannot exceed 30% state of charge. This is the single biggest operational constraint we see customers miss. Some practical implications:

  • Your contract manufacturer needs a discharge step on the line.
  • If you are consolidating partial pallets, all cells in the consignment have to be at 30% SoC or less — a single higher-SoC box disqualifies the whole load.
  • The 30% limit does NOT apply to cells contained in equipment, which is why “ship the device assembled” often solves the problem for small consignments.

Quantity limits per package

PI 965 Section II (the small-cell exception for lithium-ion ≤ 2.7 Wh per cell, ≤ 20 Wh per cell in equipment, or 100 Wh per battery in equipment) allows lighter paperwork but still caps:

  • Cells alone: no more than 8 cells or 2 batteries per package for air.
  • Net weight of lithium < 2.5 kg per package.
  • Must pass a 1.2 m drop test with no cell coming out, no short, no fire.

Above those thresholds, shipments move under PI 965 Section IA/IB — full DGR paperwork, a DGR-certified shipper, and usually a specialized forwarder.

The documents that have to travel with the goods

  1. UN 38.3 Test Summary. Since 2020 this must be available on demand from anyone in the supply chain. Your cell supplier gives you a PDF; you archive it and share with carriers on request.
  2. Shipper’s Declaration of Dangerous Goods. For Section IA/IB air shipments; sometimes required for Section IB as well, depending on the carrier.
  3. Lithium-battery mark. The red-edged black-rectangle pictogram with UN number and emergency phone.
  4. Class 9 hazard label. For Section IA/IB shipments.
  5. “Cargo Aircraft Only” label. When the consignment cannot fly on passenger aircraft.

Sea and rail

IMO IMDG for sea and ADR/RID for road and rail follow the same UN numbers and packing logic but are far more permissive on quantity and SoC. Sea is the default for high-volume programs — cheaper, no 30% SoC cap for most lithium-ion consignments (though a 30% cap applies to cargo-only aircraft loaded on a vessel for combined transport, which is rare). Transit time from Chinese ports is 18–32 days to Europe, 14–22 days to the US West Coast.

A practical checklist for your first lithium shipment

  • Confirm the UN number with your supplier in writing.
  • Ask for the UN 38.3 Test Summary before booking freight.
  • Specify SoC in the purchase order (30% for air, 50% for sea is a common convention).
  • Choose a DGR-certified forwarder even for Section II — mistakes at origin are expensive.
  • Build 3–5 extra business days into your logistics plan for origin customs.