By Steve, Editor at Prodoer Logistics
The short answer: lithium metal batteries contain metallic lithium and are primary – single-use – cells; lithium-ion batteries are secondary – rechargeable – and store energy by moving lithium ions between electrodes. From a shipping perspective the distinction is not academic: they carry different UN numbers, different packing instructions, and materially different airline acceptance, because lithium metal burns differently – it reacts with water, and firefighting it is a specialist problem. Shipping rules encode that danger difference, and misclassifying one as the other is one of the costliest errors in battery logistics.
THE CHEMISTRY DIFFERENCE THAT MATTERS
Lithium metal batteries – the classic coin and cylindrical cells in watches, calculators, and some industrial sensors – hold their energy in metallic lithium, which cannot be recharged. Lithium-ion batteries – the rechargeable workhorses in phones, power tools, e-bikes, and energy storage – hold no bulk metal lithium at all; their lithium exists as ions moving through electrolyte. The consequence in a fire: a lithium metal fire reacts with water, so conventional suppression can feed it, while lithium-ion fires are driven by thermal runaway releasing heat and flammable vapor that water can cool but not extinguish. Regulators therefore treat lithium metal cargo more restrictively – especially on passenger aircraft, where much of it is forbidden entirely – and the two families never share a packing instruction.
THE UN NUMBER MAP
Four UN numbers cover the field, and knowing them is basic literacy for battery shippers. UN 3090: lithium metal batteries shipped alone. UN 3091: lithium metal batteries packed with or contained in equipment. UN 3480: lithium-ion batteries shipped alone. UN 3481: lithium-ion batteries packed with or contained in equipment. Shipped alone means batteries as the cargo itself; packed with means in the same box as their device but not installed; contained in means installed and riding inside the equipment. Each combination sits on its own row of the dangerous goods regulations, with its own quantity limits, packaging requirements, and labeling – and state-of-charge limits, such as the thirty-percent rule for standalone lithium-ion air shipments, apply only to the shipped-alone categories.
WHY AIRLINES TREAT THEM DIFFERENTLY
Air carriers accept battery cargo through their own safety desks layered on top of the international regulations. Standalone lithium metal batteries face the tightest acceptance – many carriers refuse them outright on passenger aircraft and restrict them heavily on freighters. Standalone lithium-ion faces the thirty-percent state-of-charge ceiling, quantity limits per package, and often prior-approval requirements per lane. Batteries packed with or in equipment face the lightest regime – smaller quantity thresholds, simpler packaging – because the device structure materially constrains propagation risk. When your forwarder asks whether the battery is installed, in the box, or alone, they are not being pedantic: they are choosing between three different regulatory worlds.
THE DOCUMENTATION DIFFERENCE
Every battery shipment needs the test summary proving design-type testing to the UN 38.3 standard – both chemistries. Beyond that, the paperwork splits by category: standalone shipments travel with shipper’s dangerous goods declarations and, for air, packaging certified for the relevant packing instruction; equipment shipments may qualify for exceptions with lighter documentation. The description on the paperwork must name the chemistry correctly – the classic misdeclaration is describing lithium coin cells as generic batteries, which conceals a metal-lithium cargo inside an ion paperwork envelope. Every element of the penalty regime for battery misdeclaration exists because that specific error has brought down aircraft.
PRACTICAL GUIDANCE FOR BUYERS SOURCING BOTH
If your product line mixes chemistries – a device powered by an ion pack and shipped with a spare metal coin cell for its backup clock, for example – the shipment may contain two different UN entries with different rules, and the forwarder must be told about both. Source the test summaries for both at purchase time, keep packaging designed per category, and never let a supplier consolidate metal cells inside an ion shipment to save paperwork. The correct total cost comparison is never ion paperwork versus metal paperwork – it is paperwork versus the fine, the confiscation, and the blacklisting that follow a discovered misdeclaration.
WHAT A COMPLETE DOOR-TO-DOOR QUOTE CONTAINS
Use this checklist against any quote from China. Origin side: pickup and inland transport to the port or airport, export customs declaration and documentation, origin terminal handling, packing, consolidation, or inspection where applicable. Main leg: base freight, ocean or air, plus fuel and security surcharges. Destination side: destination terminal handling, the delivery order fee, import customs clearance, import duties and taxes – included only under DDP; under DAP or FOB they are yours – last-mile delivery, and storage beyond free time. Three items that are not fee lines but cost drivers all the same: the currency of the quote, its validity window, and the free time allowed at destination. A quote that expires within days, or assumes you can clear and collect within a tight window of arrival, is not priced like one with a longer runway. When you receive a quote, check every line above: present, absent, or collect. Absent lines are where surprises come from, and collect lines are where risk hides.
SIX QUESTIONS THAT EXPOSE ANY FORWARDER
Which lanes do you run most, and with which carriers? Forwarders are strong where they run volume; you want current rates and a live view of schedule reliability, not a generalist learning your lane on your budget. Who files the export customs declaration, and in whose name? The answer should be crisp – we file in China, in our name, as your export agent. Do you quote all-in or line by line, and can you show the lines? Either style is honest if the lines are visible on request. What exactly is your liability if my cargo is lost or damaged? Listen for honest limits and a clear insurance recommendation, not comfort. Can you quote DDP to my door? Even if you ship FOB, the answer maps the depth of their destination network. And what went wrong on a recent shipment, and what did you do? Every forwarder has war stories; the good ones tell them plainly with a resolution. Vague answers to two or more of these should end the evaluation, whatever the price.
THE MODE MAP, IN ONE PARAGRAPH
Air freight from China is the speed ceiling: transit counted in days, priced accordingly, right for launches, spare parts, and stock-outs. Sea freight is the cost floor: transit counted in weeks, unbeatable per unit for full containers and bulk replenishment. Rail to Europe sits in between – meaningfully faster than ocean, meaningfully cheaper than air – a natural fit for electronics and e-commerce restocking. International express is the small-parcel lane: a few cartons, minimal paperwork, premium pricing. Most importers end up using a portfolio: sea for the base load, air for the exceptions, and rail as the middle option when both extremes misbehave. The mistake to avoid is treating mode choice as an identity – we are a sea freight company – instead of a per-shipment decision driven by urgency and value density. A forwarder who runs all the modes can price the portfolio honestly; a single-mode operator can only sell you their mode.
WHICH RULES APPLY DEPENDS ON THE CHEMISTRY
Lithium metal and lithium-ion cargo ride under different UN numbers, different packing instructions, and different airline acceptance rules – but both demand the same thing from you: test reports, correct packaging, and a forwarder who files the declarations properly. When your cargo crosses chemistry families, ask for a desk that runs customs clearance services together with dangerous goods handling, so the customs description and the DG paperwork agree from the first filing.
Steve is the Editor at Prodoer Logistics, a China-based freight forwarder and customs broker handling air, sea, rail, and express cargo for traders, wholesalers, manufacturers, and online sellers.