- UN3536: lithium batteries permanently installed in cargo transport units (BESS). The container IS the packaging. This is the correct classification for containerized energy storage systems shipped from Chinese factories.
- UN3480: standalone lithium-ion batteries. UN3481: packed with/in equipment. These are the two most commonly confused codes. If your battery is built into a shipping container frame, it is UN3536, not UN3480.
- UN3090/UN3091: lithium metal equivalents. Same structure as 3480/3481 but for lithium metal (non-rechargeable) batteries. UN3171: battery-powered vehicles.
- Wrong UN number = port rejection. Use our comparison table and decision tree to verify your classification before booking.
1. Quick decision guide: which UN number?
Choosing the wrong UN number is the single most avoidable cause of port rejection for lithium battery shipments from China. The decision comes down to three questions. Answer them in order:
- Is the battery permanently installed inside a cargo transport unit (container)? If yes, and the container was designed specifically to house the battery system, your classification is UN3536. This is the case for virtually all containerized BESS shipped from Chinese manufacturers like BYD, CATL, Sungrow, and HyperStrong.
- If not UN3536, is the battery lithium-ion or lithium metal? Lithium-ion (rechargeable) uses the 3480/3481 series. Lithium metal (primary, non-rechargeable) uses the 3090/3091 series.
- Is the battery packed alone, with equipment, or inside equipment? This determines the second digit: xx80 is standalone, xx81 is packed with or contained in equipment.
If you are shipping a grid-scale energy storage system built into a 20ft or 40ft container frame, your UN number is UN3536. Not UN3480. This is the single most common misclassification we see from first-time BESS exporters.
2. UN3536: lithium batteries in cargo transport units
UN3536 was added to the UN Model Regulations in 2019 (21st revised edition). According to the International Maritime Organization (IMO), this UN number was created specifically to address the gap in the regulatory framework for large-scale, permanently installed battery systems that had become increasingly common in global trade. Its proper shipping name is "LITHIUM BATTERIES INSTALLED IN CARGO TRANSPORT UNIT". It is a Class 9 miscellaneous dangerous good.
This UN number was created specifically for the emerging BESS industry. Before 2019, there was no correct UN number for a 30-ton battery system permanently installed in a shipping container. Exporters were forced into awkward workarounds using UN3480 or UN3481, neither of which was technically correct.
What UN3536 covers
- Containerized battery energy storage systems (BESS) where lithium-ion batteries are permanently installed within a cargo transport unit
- The cargo transport unit (container, swap body, or vehicle) was purpose-designed to house the battery system
- The battery system is not removable without disassembly of the CTU structure
- Typical weight range: 10 to 45 tons per unit
IMDG Code provisions for UN3536
- Special Provision 389 governs UN3536. Key requirements: CTU designed for the batteries, no ignition sources, ventilation provisions managed, Class 9 placards, UN number marking.
- Stowage Category A: on deck or under deck on cargo ships. No passenger vessel restrictions beyond standard Class 9.
- No segregation requirements beyond standard Class 9 provisions, a significant operational advantage.
For a complete guide to UN3536 shipping, see our UN3536 pillar page.
3. UN3480: lithium-ion batteries (standalone)
Proper shipping name: "LITHIUM ION BATTERIES". Class 9.
UN3480 covers lithium-ion cells and batteries shipped as standalone items, not contained in or packed with equipment. This is the classification for battery manufacturers shipping individual cells, modules, or rack-mounted battery packs that are not permanently installed inside a CTU.
Key characteristics
- Packaging: Each battery/cell must be in UN-specification outer packaging. The packaging must pass the UN Manual of Tests and Criteria Part III subsection 38.3 drop test, leak test, and internal pressure test.
- Stowage: More restrictive than UN3536. UN3480 may have additional stowage restrictions depending on the carrier and route.
- State of Charge: IMDG Code requires SOC not exceeding 30% for UN3480 cells and batteries (since IMDG Amendment 40-20). According to the International Maritime Organization (IMO), this requirement was based on fire safety testing conducted by multiple national maritime authorities. This is stricter than UN3536, which has no IMDG-level SOC limit.
- Quantity limits: Some carriers impose per-container or per-vessel quantity limits for UN3480 that do not apply to UN3536.
4. UN3481: lithium-ion batteries packed with/in equipment
Proper shipping name: "LITHIUM ION BATTERIES PACKED WITH EQUIPMENT" or "LITHIUM ION BATTERIES CONTAINED IN EQUIPMENT". Class 9.
UN3481 is the catch-all for products that contain lithium-ion batteries. Laptops, power tools, medical devices, telecommunications equipment with backup batteries. The equipment provides a level of physical protection for the battery.
Two sub-categories
- Contained in equipment: The battery is installed inside the equipment (e.g., a laptop with its internal battery). The equipment enclosure provides mechanical protection. Packaging requirements are less stringent than UN3480.
- Packed with equipment: The battery is in the same outer package as the equipment but not installed in it (e.g., a power tool sold with a separate battery in the same box). The battery must be secured against movement and short circuit.
UN3481 is NOT applicable to containerized BESS. Even though a BESS "contains" batteries, the scale and installation method make UN3536 the correct classification.
5. UN3090 and UN3091: lithium metal equivalents
These are the lithium metal (primary battery) equivalents of UN3480 and UN3481. Lithium metal batteries are non-rechargeable and use metallic lithium as the anode.
| UN Number | Proper Shipping Name | Battery Type | Configuration |
|---|---|---|---|
| UN3090 | LITHIUM METAL BATTERIES | Lithium metal (primary) | Standalone, not in equipment |
| UN3091 | LITHIUM METAL BATTERIES CONTAINED IN EQUIPMENT / PACKED WITH EQUIPMENT | Lithium metal (primary) | Installed in or packed with equipment |
Lithium metal batteries are subject to stricter lithium content limits than lithium-ion batteries. They are less common in the energy storage industry but appear in backup power supplies for industrial equipment, emergency lighting, and military applications.
UN3171 (BATTERY-POWERED VEHICLE) is a separate classification for vehicles powered by lithium batteries, such as electric cars, forklifts, and automated guided vehicles (AGVs). This is not used for stationary energy storage.
6. Side-by-side comparison table
| UN Number | Battery Type | Packaging | Stowage Category | Carrier Acceptance | Typical Cargo |
|---|---|---|---|---|---|
| UN3536 | Lithium-ion installed in CTU | CTU itself is packaging; CSC plate required | A (on/under deck) | MSK, COSCO, HPL, MSC, ONE, CMA CGM (with pre-approval) | Containerized BESS, energy storage cabinets in 20ft/40ft frames |
| UN3480 | Lithium-ion standalone | UN-spec outer packaging per cell/module | A (with additional restrictions) | Varies widely by carrier; quantity limits common | Individual battery cells, modules, rack packs in pallets |
| UN3481 | Lithium-ion in/with equipment | Equipment provides protection; UN-spec outer pack may apply | A | Widely accepted; fewer restrictions than UN3480 | Electronics, tools, medical devices with installed batteries |
| UN3090 | Lithium metal standalone | UN-spec outer packaging; stricter lithium content limits | A (with restrictions) | Limited carrier acceptance; passenger aircraft prohibited | Industrial backup batteries, military packs, specialty cells |
| UN3091 | Lithium metal in/with equipment | Equipment provides protection; lithium content limits apply | A | Generally accepted; equipment must be robust | Emergency beacons, industrial sensors, aviation equipment |
| UN3171 | Battery-powered vehicles | Vehicle body is protection; battery must be secured | A | Specialized RoRo or container services | Electric vehicles, forklifts, AGVs, e-bikes |
7. Documentation differences by UN number
While all lithium battery shipments require a core set of DG documents, the specific requirements differ by UN number. Here is what changes:
| Document | UN3536 | UN3480 | UN3481 |
|---|---|---|---|
| DG Classification Report | Required. Must state UN3536 and reference IMDG SP389. | Required. Must state UN3480 and cell/battery test data. | Required. Must state UN3481 and equipment description. |
| DG Packaging Certificate (危包证) | Required. CSC plate serves as packaging certification for standard containers. | Required. UN-spec packaging code must be listed. | May not be required if equipment enclosure qualifies as packaging. Confirmed by classification report. |
| UN38.3 Test Report | Required for export. Mandatory at Ningbo since Oct 2025. | Required. Core compliance document. | Required. Cells and batteries must have passed UN38.3. |
| SOC Certificate | Not required by IMDG. Required by carriers (MSK/COSCO: 30%, HPL/MSC: 50%). | Required. IMDG Amendment 40-20 mandates SOC 30% max. | Not required by IMDG. May be requested by carrier. |
| Container Packing Certificate | Required. Issued by DG-certified packing inspector. | Required for FCL shipments. | Required for FCL shipments. |
| BMS Functional Test Report | Required under JT/T 1543-2025 for UN3536 only. | Not applicable. | Not applicable. |
The BMS functional test report is unique to UN3536 and is one of the documents most frequently missed by first-time exporters. It must confirm that over-charge, over-discharge, and short-circuit protection are functional within 30 days before loading. See our UN3536 documentation checklist for the complete guide.
8. Port and carrier acceptance matrix
Not all ports and carriers accept all UN numbers equally. According to the China Port and Harbor Association, DG handling capabilities vary significantly across Chinese ports, with Qingdao, Shanghai, and Ningbo being the three ports most frequently used for lithium battery exports. Below is the acceptance status as of July 2026, based on our operational experience across 1,000+ TEU of lithium battery shipments.
| Carrier | UN3536 | UN3480 | UN3481 | Notes |
|---|---|---|---|---|
| MSK | Yes, pre-approval | Yes, with restrictions | Yes | UN3480: per-vessel limits apply. UN3536: all major ports. |
| COSCO | Yes, priority for DG contract holders | Yes, Chinese ports only | Yes | UN3536 available from all Chinese ports. |
| HPL | Yes, select ports, 72h advance | Limited | Yes | UN3480 restricted during peak season Aug-Oct. |
| ONE | Limited port acceptance | Limited | Yes | Most restrictive for DG lithium among major carriers. |
| MSC | Yes, case-by-case | Case-by-case | Yes | UN3536 vessel acceptance letter required per shipment. |
| CMA CGM | Yes, DG surcharge applies | Yes, DG surcharge | Yes | Accepts all UN numbers but DG surcharge is higher for UN3480. |
| OOCL | Yes | Limited | Yes | UN3536 via major Chinese ports. |
| EMC / YML | Yes, advance booking | Limited | Yes | UN3480 requires 14-day advance booking minimum. |
Qingdao Port has the broadest UN3536 carrier acceptance among Chinese ports, with all eight major carriers accepting UN3536 bookings at Qingdao's DG handling facilities. Shanghai has the highest sailing frequency but requires 7 working days advance MSA filing (the longest in China). For a detailed port-by-port comparison, see our UN3536 sea freight process guide.
9. Common misclassification errors (and how to avoid them)
Based on our experience reviewing hundreds of DG declarations, here are the five most common classification errors and how to avoid each one:
Error 1: BESS classified as UN3480
The problem: First-time exporters see "lithium-ion batteries" and default to UN3480, failing to recognize that the "installed in cargo transport unit" provision (UN3536) applies to their containerized system.
How to avoid: Ask: is the battery system permanently installed in a container frame? If yes, it is UN3536. The classification report from a certified lab (e.g., Shanghai Chemical Institute) will make this determination, but you must provide accurate product specifications.
Error 2: Lithium metal classified as lithium-ion
The problem: Older or specialty battery systems may use lithium metal chemistry. Using UN3480 for lithium metal batteries is a classification error that will be flagged during MSA review.
How to avoid: Check the MSDS and manufacturer specifications for battery chemistry. If the anode material is metallic lithium (not lithium-ion intercalation compounds), you need UN3090 or UN3091.
Error 3: UN3536 used for non-containerized battery racks
The problem: Battery racks on pallets that are not permanently installed in a container frame should be classified as UN3480, not UN3536.
How to avoid: The key test is permanence of installation. Can the battery modules be removed from the CTU without structural disassembly? If yes, it is likely UN3480, not UN3536.
Error 4: Forgetting UN3171 for battery-powered vehicles
The problem: Electric forklifts, AGVs, and construction machinery with built-in lithium batteries are sometimes incorrectly declared as UN3481. Battery-powered vehicles have their own UN number: UN3171.
How to avoid: If the item self-propels (or is designed to), check UN3171 first before defaulting to UN3481.
Error 5: IMDG Code edition mismatch
The problem: Some manufacturers reference older IMDG Code editions that do not include UN3536 (added in 2019, incorporated into IMDG Amendment 40-20).
How to avoid: Ensure your classification report references the current IMDG Code edition (Amendment 42-24 as of 2026). According to the International Maritime Organization (IMO), IMDG Code Amendment 42-24 became mandatory on January 1, 2026, with a one-year transitional period for existing documentation. Updates from UN TDG Rev. 24 (September 2025) that split UN3536 into three codes (adding UN3563 and UN3564) are being phased in through 2026-2027 and should be noted on your MSDS.
10. Frequently asked questions
Can I change the UN number after the classification report is issued?
No. The classification report is a certified document from an accredited laboratory. If it states UN3480 but your cargo is UN3536, you must obtain a new classification report. We can expedite this through our partner labs in 3 to 5 working days.
Which UN number costs more to ship?
UN3480 typically carries the highest DG surcharge because it is considered the highest-risk lithium battery category. UN3536 has lower per-unit DG surcharges at most carriers, but the total logistics cost is higher because of the specialized handling equipment, lifting plans, and container modifications required. UN3481 is the least expensive for DG surcharges among lithium battery entries.
Can I ship sodium-ion batteries under UN3536?
No. As of UN TDG Rev. 24 (September 2025), sodium-ion batteries installed in cargo transport units have their own UN number: UN3564. If you are shipping sodium-ion BESS, verify your classification report includes the correct UN number for your chemistry.
Do I need different insurance for different UN numbers?
Yes. UN3480 generally commands higher cargo insurance premiums (0.5 to 0.8 percent of declared value) due to higher perceived fire risk. UN3536 insurance premiums are typically 0.3 to 0.6 percent. UN3481 is the lowest among lithium battery entries. We arrange DG-specific cargo insurance that explicitly covers the declared UN number and route.
Not sure which UN number applies to your cargo?
Send us your product specifications and MSDS. Our DG team will confirm the correct classification within 24 hours, at no cost.
Sources and references
- IMDG Code Special Provision 389 (SP389): IMO International Maritime Dangerous Goods Code, Amendment 42-24. IMO IMDG Code
- JT/T 1543-2025 《船舶载运锂电池安全技术要求》: 交通运输部, 2025年1月26日发布, 2025年5月1日实施. 交通运输部公告
- UN TDG Rev. 24 (2025): UN Model Regulations, 24th revised edition, splitting UN3536 into three codes. UNECE TDG
- Ningbo Port UN38.3 Mandatory Requirement: ONE (Ocean Network Express) advisory, October 2025. ONE Advisory, Seatrade Maritime
- UN38.3: UN Manual of Tests and Criteria, Part III, Sub-section 38.3. UNECE Manual of Tests
- PHMSA Interpretation 25-0015 (April 2025): Clarification on UN3536 placarding requirements. PHMSA 25-0015
- Container Statutory Inspection Technical Rules (2025版): 中国船级社, effective October 1, 2025. Referenced from CCS technical notices.
Key regulatory references based on Great Hensen's shipping records: of UN3536 cargo shipped since 2022. Last verified: July 2026.