Starting from January 1, 2026, vehicles equipped with lithium batteries will no longer fall under UN 3171 (BATTERY POWERED VEHICLE) but will be shifted to UN 3556 (VEHICLE, LITHIUM ION BATTERY POWERED) in accordance with the new United Nations regulations. During the transition period, until December 31, 2025, businesses must still declare under UN 3171.
This change is particularly important in the context of the growing popularity of electric and hybrid vehicles. Incorrectly declaring the UN Code can result in cargo being held at ports, incurring storage costs, administrative penalties, or even being forced to re-export or destroy goods. Misclassification also poses potential risks to transport safety due to non-compliance with international standards.
1. What is a lithium battery? What is a UN Code?
Lithium batteries are batteries that use lithium metal or lithium compounds to store energy. With high capacity, lightweight, and long lifespan, lithium batteries are widely applied in electric vehicles, electronic devices, autonomous machinery, and many modern industries. However, lithium batteries also carry risks of fire, explosion, or short-circuiting if not transported and handled properly.
UN Code (United Nations Code) is an international numbering system issued by the UN to classify dangerous goods, including lithium batteries and vehicles containing them. Each type of battery or battery-powered vehicle is assigned a unique UN number, allowing businesses to declare customs accurately, ensure safe transportation, and comply with international law.
2. Case 1: Lithium battery installed in vehicles when transported
According to the United Nations Recommendations on the Transport of Dangerous Goods, Volume I, 2023, vehicles with lithium batteries are subject to different UN numbers depending on the time frame:
- Until December 31, 2025: use UN 3171 – BATTERY POWERED VEHICLE
- From January 1, 2026: shift to UN 3556 – VEHICLE, LITHIUM ION BATTERY POWERED
To help businesses easily apply the correct codes, below is a summary table of UN numbers related to vehicles powered by batteries or special engines:
| UN Code | Vehicle Description | Applicable Battery/Engine | Notes |
| UN 3166 VEHICLE, FLAMMABLE LIQUID/GAS POWERED | Vehicles powered by internal combustion engines using flammable liquid or gas | – Internal combustion (liquid/gas) – Hybrid: internal combustion + batteries (wet, sodium, lithium metal, lithium ion) |
If using both liquid + gas → classified as UN 3166, FLAMMABLE GAS POWERED |
| UN 3166 VEHICLE, FUEL CELL, FLAMMABLE GAS/LIQUID POWERED | Vehicles powered by fuel cells | – Fuel cell (gas or liquid) – Hybrid: fuel cell + combustion engine + batteries (wet, sodium, lithium metal, lithium ion) |
Includes fuel cell hybrid vehicles |
| UN 3171 BATTERY POWERED VEHICLE | Battery-powered vehicles & equipment (traditional) | – Wet batteries – Sodium metal batteries – Sodium alloy batteries |
Only applies when batteries are already installed |
| UN 3556 VEHICLE, LITHIUM ION BATTERY POWERED | Vehicles powered by lithium-ion batteries | – Lithium-ion batteries | Effective Jan 1, 2026, replacing UN 3171 for EVs with lithium-ion |
| UN 3557 VEHICLE, LITHIUM METAL BATTERY POWERED | Vehicles powered by lithium-metal batteries | – Lithium-metal batteries | Applies to EVs with lithium-metal batteries |
| UN 3558 VEHICLE, SODIUM ION BATTERY POWERED | Vehicles powered by sodium-ion batteries | – Sodium-ion batteries | Applies to EVs with sodium-ion batteries |
| UN 3091 (CONTAINED IN EQUIPMENT / PACKED WITH EQUIPMENT) | Battery-powered devices | – Lithium metal batteries – Lithium-ion batteries |
Classified depending on whether the battery is contained in or packed with equipment |
| UN 3536 LITHIUM BATTERIES INSTALLED IN CARGO TRANSPORT UNIT | Batteries installed in transport units (for external supply) | – Lithium metal batteries – Lithium-ion batteries |
Only applies when the battery powers equipment outside the unit |
Note:
1. Definition of “Vehicle”: Self-propelled devices designed to carry one or more persons or goods.
- Examples: cars, motorcycles, scooters, three- or four-wheel vehicles, trucks, locomotives, e-bikes, self-balancing vehicles, non-seated vehicles, wheelchairs, lawn tractors, agricultural & construction machinery, boats, aircraft.
- Remark: Some parts (excluding batteries) may be removed during packing to meet packaging requirements.
2. Examples of “Equipment”: lawnmowers, cleaning machines, model boats, model aircraft.
2. Case 2: Lithium battery transported separately (not installed in vehicles)
In some cases, businesses may transport the batteries separately along with the vehicles, rather than pre-installing them. In this case, the applicable regulation is:
UN 3481 – LITHIUM ION BATTERIES PACKED WITH EQUIPMENT (including lithium-ion polymer).
(United Nations, Recommendations on the Transport of Dangerous Goods, Vol. I, 2023, p. 173)
Under Chapter 2.9 – Class 9 of the UN system, this group is categorized as “Miscellaneous Dangerous Goods.”
CHAPTER 2.9 – CLASS 9: MISCELLANEOUS DANGEROUS GOODS, INCLUDING ENVIRONMENTALLY HAZARDOUS SUBSTANCES
| Section | Content |
| 2.9.1 – Definition | 2.9.1.1: Class 9 includes substances/goods which present hazards during transport but do not fall into other classes. 2.9.1.2: Deleted. |
| 2.9.2 – Classification | Substances/goods under Class 9 are divided into groups. One of them is lithium batteries. |
| Lithium batteries:
|
|
3. Why is the correct UN Code classification important?
Correct UN Code application is not only a legal requirement but also has significant practical implications for businesses:
- Compliance with international regulations: Goods move across multiple countries; misclassification can easily lead to violations and penalties.
- Ensuring transport safety: Lithium batteries pose risks of fire, leakage, or short-circuiting if not handled properly.
- Reducing logistics risks: Goods may be held at ports or returned if documentation is inconsistent.
4. Recommendations for businesses
- Stay updated on the change from UN 3171 to UN 3556, effective January 1, 2026.
- Carefully consider each transport scenario: whether the battery is installed or shipped separately, to apply the correct UN number.
- Work with experienced logistics providers and customs consultants, such as UNI Customs Consulting, to save time and reduce risks of re-declaration.
5. Smooth customs declaration with UNI’s experts
With global transport regulations becoming stricter, accurate UN Code application is the key to ensuring compliance, safety, and cost optimization.
With 10 years of expertise in product classification, UN code determination, documentation, and customs clearance, UNI Customs Consulting has successfully supported numerous businesses in handling imports and exports of products containing lithium batteries – a highly specialized cargo group requiring deep knowledge and strict compliance with international standards.
Read more: E3 VINA From Automechanika 2025 to Market Success: UNI’s Complete Import Strategy
In 2025, UNI helped a Korean electric motorbike importer in Vietnam resolve a UN Code conflict involving lithium-ion batteries. As a result, the shipment was approved by the carrier, transported safely to Vietnam, and the importer avoided potential legal violations and logistics risks.
If your business needs consultation or customs declaration for goods containing lithium batteries, let UNI’s expert team accompany you from classification and documentation to customs filing. We are committed to delivering fast, accurate, and safe solutions for your supply chain.
Contact us right now to receive quotation and consultation:
📞 Contact UNI Customs Consulting for free consultation:
📧 Email: uni@eximuni.com
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