Lithium batteries are one of the most heavily regulated materials in the supply chain, and for good reason: as more products ship with batteries built in, from power tools to electric vehicle components, the packaging around them carries real safety stakes. Before a lithium battery product can legally move by truck, rail, ocean, or air, its packaging typically has to earn UN/DOT certification.

Whether you're shipping a case of replacement batteries or a large crate for an EV battery pack, the certification process generally follows the same core principles.

What Requires Certified Packaging

If your product ships with lithium-ion or lithium-metal cells inside (power tools, e-bikes, consumer electronics, energy storage systems, EV components) the outer packaging is regulated under 49 CFR 173.185 and must be tested and certified before it ships. This applies at every scale, from a single corrugated carton holding a handful of cells to a large reusable crate holding a full battery module.

Not every battery shipment needs full UN performance testing, though. Products with very small cells or limited lithium content may qualify for the DOT's excepted quantity provisions, which reduce packaging and marking requirements. If you're not sure whether your product qualifies, it's worth confirming before assuming you need full certification. Reach out to us and we are happy to provide guidance

Packing Groups: Why They Matter

Certified packaging is tested and marked to a Packing Group (either I, II, or III), which reflects the level of protection required. Packing Group is determined by the hazard classification of what's inside, and it shapes everything from drop height to compression requirements during testing. This is usually the first thing to nail down before testing begins, since it determines which tests apply and how demanding they are.

Where do you find your Packing Group? For most products, it's already documented in the material's Safety Data Sheet (SDS) or in the shipping documentation your battery manufacturer provides. It can also be looked up directly in the Hazardous Materials Table (49 CFR §172.101 - see Column 5 of the table), which lists the required Packing Group for each type of regulated material.

Small Packages vs. Large Packaging

Certification requirements look a little different depending on scale. A standard carton or box falls under general package testing: drop, vibration, and stacking tests sized to its weight and volume. Larger crates, pallets, and reusable containers fall under “Large Packaging” designations, which come with their own test protocols, including bottom-lift and higher load testing. Knowing which category your packaging falls into early on avoids surprises in cost and turnaround time.

When You Need to Recertify

UN/DOT certification isn't a one-time event. Recertification is typically required when the packaging design changes, when the certified weight increases, or simply after a set period of time passes (typically every two years, but it depends on the packaging type). Companies that scale up production, switch suppliers, increase weight, or change supporting structures, among other things, should expect to recertify, even if the outer packaging looks unchanged. We are happy to provide our opinion or reach out to the DOT on your behalf to determine if a retest is necessary.

Preparing for Testing

A little preparation shortens the process considerably. Labs typically need engineering drawings for every component, the actual weight of the battery contents (or accurate dummy loads), and a clear understanding of how the packaging will be stacked or handled during transport. It's also worth knowing that some tests can damage the unit, so we often request multiple sets of units or components to help test more efficiently.

Shipping Internationally

If your batteries are moving beyond the US by ocean or air, DOT certification is the starting point, but not the finish line. International shipments are also subject to IMDG (ocean) or ICAO/IATA (air) dangerous goods regulations, which reference the same UN performance standards but carry their own documentation requirements. It's worth confirming international requirements early if your shipping lanes extend beyond domestic ground transport.

How Gaynes Labs Can Help

Gaynes Labs is a DOT-authorized hazmat testing laboratory and one of fewer than 20 facilities in the US certified to perform UN/DOT package testing. We work across the full range of battery packaging and help a variety of large and small companies test, certify, and stay ahead of recertification deadlines.

If you're shipping lithium batteries and need packaging certified, recertified, or evaluated, contact Gaynes Labs at sales@gaynestesting.com or (708) 233-6655.