Quick answer: Lithium battery packaging requires non-metallic inner packaging that completely encloses each cell or battery to prevent short circuits, terminal protection, and a strong rigid outer packaging. Fully regulated cells over 20 Wh and batteries over 100 Wh need UN-specification packaging tested to Packing Group II performance and a 1.2-meter drop test.
Lithium battery packaging is where most battery non-compliance starts, because the box does the safety work the label only describes. The regulations target three specific failure modes, short circuits, contents shifting, and accidental activation, and every packaging rule exists to prevent one of them. This guide breaks down inner packaging, cushioning, and outer packaging, clears up the overpack-versus-combination-package confusion that trips up shippers, and gives a spec breakdown by battery type. It is a companion to our hazmat shipping overview and applies the packaging layer beneath every lithium shipment, alongside our guide to commercial lithium battery shipping by ground, bulk, and in equipment.
The core function: preventing short circuits
Every lithium battery packaging rule serves one primary job, stopping terminals from contacting each other or any conductive material. A short circuit is what triggers thermal runaway, so the packaging is the first line of defense against a fire. Federal rules require that the package prevent short circuits, prevent damage from shifting or placement, and prevent accidental activation of any equipment, and that cells and batteries have a means of preventing external short circuits (49 CFR 173.185, PHMSA). Reading the packaging spec through this single lens, everything is about isolating terminals, makes the rest of the requirements follow logically.
Inner packaging and cushioning
Inner packaging is what isolates each cell, and the rule is specific: non-metallic inner packaging must completely enclose the cells or batteries. That means each unit is separated so terminals cannot touch each other, the outer box, or stray conductive material. Exposed terminals get additional protection, non-conductive caps, non-conductive tape, or equivalent, and batteries are spaced or divided so they cannot shift into contact.
Cushioning prevents movement inside the package, which is itself a named requirement, since a battery that shifts can breach or short. One nuance matters here: non-combustible, non-conductive absorbent cushioning is specifically required for damaged, defective, and recalled batteries and certain waste shipments, not for every routine shipment. For standard cells and batteries, the requirement is cushioning that prevents shifting, not a special absorbent medium. Our guide to shipping damaged and defective lithium batteries covers the stricter packaging those units demand.
Outer packaging and the drop test
The outer packaging has to survive the trip, and for fully regulated batteries that means certified performance packaging. Fully regulated cells and batteries require UN-specification packaging tested to the Packing Group II performance level, common real-world examples being 4G fiberboard boxes or equivalent metal, wood, or plastic containers. Every package, regulated or excepted, must be capable of withstanding a 1.2-meter drop test in any orientation without damaging the cells or shifting the contents in a way that allows terminal contact, and cells or batteries must sit in a strong rigid outer package unless they are contained in equipment. That drop test is the practical proof that the package will protect the batteries through normal handling.
Excepted or fully regulated? The thresholds by battery type
Whether a battery needs full UN-specification packaging or lighter excepted packaging comes down to energy content, and the thresholds differ by chemistry. The table below is the decision point that drives which packaging spec applies.
Battery typeExcepted (lighter packaging)Fully regulated (UN-spec)
Lithium-ion cell
20 Wh or less
Over 20 Wh
Lithium-ion battery
100 Wh or less
Over 100 Wh
Lithium-metal cell
1 g lithium or less
Over 1 g
Lithium-metal battery
2 g lithium or less
Over 2 g
Read it as the first question of every shipment. Identify the chemistry, check the watt-hour or lithium-gram rating against the limit, and the answer tells you whether you need certified UN-specification packaging or a strong rigid excepted package. Both still require short-circuit protection and a package that passes the drop test; the difference is the certification and performance level of the outer box.
Overpack versus combination package
The single most confused pair of terms in battery shipping is overpack and combination package, and getting them wrong causes marking errors. A combination packaging is one or more inner packagings secured inside a single non-bulk outer packaging, in other words, a single complete package. An overpack is different: it is a consignor's enclosure that consolidates one or more already-complete packages for protection or handling convenience, like several boxes strapped to a pallet and shrink-wrapped, or placed inside a larger crate (49 CFR 171.8).
The distinction has a practical consequence. An overpack does not replace the required packaging inside it, and it carries its own marking rule: it must be marked OVERPACK in lettering at least 12 mm high when specification packaging is required, and it must display the marks and labels for each hazardous material inside unless those inner marks are visible through or on the overpack (49 CFR 173.25). Treating an overpack as if it were the primary package, and skipping the inner packaging or the overpack marking, is a common and avoidable violation.
Packaging for air transport
Air shipments carry the strictest packaging rules, organized by packing instruction. Under the international air rules, lithium batteries are packaged according to Packing Instructions 965 through 970: 965, 966, and 967 cover lithium-ion (standalone, packed with equipment, and contained in equipment), and 968 through 970 cover lithium metal in the same three configurations (IATA, 2026). Air packaging also layers in a state-of-charge limit for standalone batteries and additional stacking-strength requirements that ground shipments do not face. If a shipment may travel by air at any point, package to the air standard, because a battery prepared for the ground can be refused for air, but the reverse holds up. For the vehicle side of this, our hybrid and electric vehicle shipping guide covers installed packs.
Common packaging mistakes that get loads refused
Most packaging refusals trace to a short list of errors, and all of them are avoidable at the bench. Check your process against these:
- Metal inner packaging or exposed terminals, the direct short-circuit risk the rules exist to prevent.
- Loose batteries that can shift into contact because cushioning was skipped or inadequate.
- Non-specification outer boxes used for fully regulated batteries that require UN-specification, Packing Group II packaging.
- Overpack marking omitted, treating a pallet of packages as if the shrink wrap were the package.
- Packaging to the ground standard for a shipment that will travel by air at some point.
Each of these turns an otherwise compliant shipment into a refused one, and each is caught by a two-minute check before the load leaves. The cost of that check is trivial next to demurrage on held freight or the liability of a battery fire in transit. Building the check into a standard packing procedure, rather than leaving it to memory, is what keeps a busy shipping operation from letting one of these errors slip through on a high-volume day.
Where packaging fits the compliance stack
Packaging is one layer of a larger compliance stack, and it has to line up with the others to clear a shipment. Correct packaging still needs correct marking and labeling on the outside, the lithium battery mark or Class 9 label as applicable, the correct shipping papers where required, and a battery that passed UN 38.3 testing in the first place. The package can be perfect and the load still refused if the marks are wrong or the documentation is missing, and vice versa. Think of packaging as the physical layer that the paperwork describes: the two have to match, and both have to be right, because a carrier or inspector checks them together and a mismatch between the box and the papers is enough to hold the load. A shipment clears when the battery is qualified, packaged, marked, and documented as a consistent whole, which is why experienced shippers audit all four together rather than one at a time. Our hazmat shipping and load rates guide covers how these layers affect what a compliant shipment costs to move.
Batteries installed in or packed with equipment
Not every battery ships loose, and the packaging rules ease somewhat when a battery is installed in or packed with equipment. When a cell or battery is contained in equipment, the equipment itself can serve as the strong rigid outer packaging, provided it protects the battery and prevents accidental activation, which is why a laptop or a tool does not need a separate certified box around its installed battery. When batteries are packed with equipment but not installed, they still need their own inner packaging and short-circuit protection inside the shared outer package. The configuration, standalone, packed with, or contained in equipment, is one of the first things to establish for any shipment, because it changes both the UN number and the packaging obligation. Getting the configuration right up front prevents packing a contained-in-equipment shipment as if it were loose cells, or the reverse, either of which can produce a non-compliant package. This is the same configuration logic that runs through classification and marking, which is why experienced shippers settle it before they touch a box. It also affects how the finished shipment is marked and papered, so establishing the configuration early keeps the whole compliance chain consistent from the first decision to the last label.
A packaging compliance checklist
Before a lithium battery shipment leaves the dock, confirm:
- Chemistry and rating identified, so you know whether the shipment is excepted or fully regulated.
- Each cell fully enclosed in non-metallic inner packaging with terminals protected.
- Batteries spaced and cushioned so nothing shifts into contact.
- Correct outer packaging: UN-specification to Packing Group II for fully regulated, strong rigid for excepted.
- Drop-test capability confirmed for the complete package.
- Overpack handled correctly if used: inner packaging intact, OVERPACK marked, labels visible or reproduced.
- Air standard applied if any leg travels by aircraft.
Frequently asked questions
What is the difference between an overpack and a combination package for lithium batteries?
A combination package is inner packaging inside a single non-bulk outer packaging, while an overpack is a consignor's enclosure that bundles one or more already-complete packages and never replaces the required packaging.
Do lithium batteries need UN-specification packaging?
Fully regulated cells over 20 Wh and batteries over 100 Wh require UN-specification outer packaging tested to Packing Group II performance, while smaller excepted units need only a strong rigid package that passes the drop test.
What is the drop test requirement for lithium battery packaging?
Packages must withstand a 1.2-meter drop in any orientation without damaging the cells, shifting contents, or allowing terminal-to-terminal contact.
How do you prevent short circuits when packaging lithium batteries?
Completely enclose each cell or battery in non-conductive inner packaging, separate them so terminals cannot touch each other or conductive material, and protect exposed terminals with non-conductive caps or tape.
When do you have to mark a package OVERPACK?
You mark OVERPACK in lettering at least 12 mm high when specification packaging is required and the required marks and labels on the inner packages are not visible from outside the overpack.
What watt-hour rating makes a lithium battery fully regulated?
Lithium-ion cells above 20 Wh and batteries above 100 Wh, and lithium-metal cells above 1 g or batteries above 2 g of lithium, fall outside the exceptions and ship as fully regulated Class 9.
Does cushioning for lithium batteries have to be non-combustible?
Non-combustible, non-conductive absorbent cushioning is specifically required for damaged, defective, and recalled batteries and certain waste shipments; standard cells and batteries need cushioning that prevents shifting, not a special absorbent medium.
Can I reuse a battery box for shipping?
Only if it still meets the required specification and passes the drop test intact; a damaged or degraded box, or one that no longer matches the battery's regulated tier, should not be reused for a compliant shipment.
Not sure your battery packaging will clear a carrier's inspection? Request a compliance review and we will check your inner packaging, outer spec, and overpack marking before the load moves.
