On 9 April 2026, Vietnam's Ministry of Construction issued Circular 13/2026/TT-BXD with a new national technical regulation for electric motorcycle and electric moped batteries: QCVN 31:2026/BXD. It takes effect on 9 October 2026 and replaces QCVN 91:2024, which had been in force only since January 2025.
The press summary was short: battery safety is tightened. After reading both regulations side by side, our view is more detailed. Some tests are now harder and more realistic, one important test has been removed, and swappable batteries are treated as their own category for the first time. For pack makers, importers and battery swapping operators, these details decide what has to be tested, redesigned or added to their own specifications.
Our founder, Mustafa Şimşek, has led electric motorcycle battery pack development, from cell selection to pack validation. This article explains what changed, what it means in practice, and what the regulation still leaves to the manufacturer.
What the new regulation covers
QCVN 31:2026/BXD applies to new batteries for electric motorcycles and electric mopeds in production, assembly and import. It covers lead-acid, nickel metal hydride and lithium-ion batteries. Electric bicycles are not named in the regulation.
The test object is the finished battery. For each battery type, the applicant provides four finished batteries, plus one battery assembly for each registered assembly type. The regulation does not reference UN 38.3, IEC or other international standards.
The transition is simple. Applications received before 9 October 2026 continue under the old rules, and test reports issued before that date can still be used for certification.
Swappable batteries are now a separate category
The old regulation treated all batteries the same way. The new one defines a removable battery as a battery designed so that the user can easily take it out of the vehicle and charge it outside. In the type documents, the manufacturer must now state whether a lithium-ion or NiMH battery is removable or not.
This matters because the drop test now depends on this category:
- Old rule: every lithium-ion and NiMH battery had to pass a drop test, six free drops in different directions from 1.0 m onto concrete, at 90% charge or more.
- New rule: the same drop test applies only to removable batteries.
For swappable batteries, this is the right decision. A swap battery is carried by hand, lifted in and out of a station many times a day, and sometimes dropped on the street. The drop test is the test that is closest to its real life.
For fixed batteries, we would have kept the drop test. A fixed pack is also handled in the factory, in service and in the spare parts chain, and a pack that is shipped as a spare part is treated as a transport item. Lithium batteries shipped by air or sea must pass UN 38.3 under international dangerous goods rules. UN 38.3 tests the battery for vibration, shock, external short circuit, and impact or crush, but it does not drop the bare battery. The drop test in the transport rules is applied to the package: a package with lithium batteries must withstand a 1.2 m drop. This protects the battery inside its packaging during shipping. It does not cover the bare battery that is carried and handled in the factory or the workshop. Our recommendation to manufacturers is to keep the drop test for fixed batteries too, as part of their internal design validation standard. It would also be a good step if a future update of QCVN 31 referenced UN 38.3 for packs that are shipped as spare parts or exported.
Saltwater replaces freshwater in the immersion test
This is the change that will affect pack design most.
- Old rule: the fully charged battery was submerged in water for 24 hours, then kept at ambient conditions for 6 hours. Ignition, leakage, fire or explosion meant a fail.
- New rule: the fully charged battery is submerged in a 3.5% to 5.0% sodium chloride solution for 2 hours. Fire or explosion during the test or within one hour after it means a fail.
At first sight, 2 hours looks easier than 24 hours. It is not. The two tests check different failure modes.
Clean water conducts electricity poorly. Seawater typically conducts it hundreds of times better or more, depending on the local water. In a freshwater test, a small leak path can stay harmless for a long time. Our founder saw this directly in a pack test: a 50/50 mixture of water and glycol was pumped into a sealed pack, and only after about 48 hours did the first fault appear. The pack still did not catch fire.
In our experience, the same leak path behaves very differently in salt water. Current can start to flow between terminals, busbars and the BMS board within minutes. Electrolysis produces gas, corrosion attacks the connections, and an internal short circuit can follow. The failure appears early, so a shorter test is enough to find it. China's traction battery safety standard for electric vehicles, GB 38031, includes the same test, 3.5% NaCl for 2 hours, as one of its immersion options.
The new test is also closer to what happens in Vietnam. When Typhoon Yagi flooded large parts of northern Vietnam in September 2024, many vehicles, including electric motorcycles, stood in flood water, and Vietnamese media published guidance on how to check flooded electric motorbikes before charging them. Flood water carries mud, salts and pollutants, and in coastal provinces it can mix with seawater. It is not clean water, and a test with conductive water is more realistic.
The 2-hour duration can still be discussed. A short saltwater test does not check slow water ingress through seals over a full day. The pass criterion is also narrower: leakage and ignition are no longer a fail, only fire and explosion. For this reason, we recommend a 24-hour water ingress test for both fixed and swappable batteries, as part of the manufacturer's internal design validation standard. This matters most for swap batteries that stand in rain at open stations.
The cell crush test has been removed
The old regulation asked for one separate cell for lithium-ion and NiMH batteries and tested it in a crush test. The cell was pressed with a 150 mm bar or sphere at no more than 6 mm per minute, until one of three conditions was reached: a sudden voltage drop of one third of the initial voltage, a deformation of 15%, or a force of 1,000 times the cell weight. Fire or explosion meant a fail.
The new regulation has no crush test and no separate cell sample.
The regulation no longer looks at the cell itself. The quality of the cell inside the pack is now fully the responsibility of the pack maker and the buyer. In a market where cells are also sold through traders, with unclear grade and origin, this is the point where incoming inspection and supplier audits matter most.
Other changes in the new text
- Smoke now counts as fire. The old rule counted only a visible flame. Under the new rule, a battery is considered on fire when smoke or flame comes out of it.
- The casing must stay finger-proof at any voltage. After the overcharge, over-discharge, vibration, short-circuit and drop tests, a standard test finger is pushed into any opening in the casing with a force of 10 N. If it touches parts inside, the battery fails. Under the old rule, this check applied only to batteries above 60 V. The check looks for large openings only. It does not test water tightness.
- Unchanged: overcharge, over-discharge, vibration (7 to 200 Hz, 3 hours) and external short circuit (below 5 mΩ) keep the same methods.
Old and new rules side by side
For lithium-ion batteries:
- Drop test, 1.0 m, 6 times: the old rule required it for every battery. The new rule requires it only for swappable batteries.
- Immersion: the old rule used 24 hours in water. The new rule uses 2 hours in a 3.5% to 5.0% NaCl solution, for fixed and swappable batteries.
- Cell crush: the old rule required it on a separate cell. The new rule removed it.
- Fire definition: the old rule counted only a visible flame. The new rule counts smoke or flame.
- Finger-proof casing after the test: the old rule checked it only above 60 V. The new rule checks it at any voltage.
- Overcharge, over-discharge, vibration, short circuit: required in both rules, with the same method.
What the regulation still does not test
The new regulation is a pass or fail check of the finished battery under abuse. It does not include:
- BMS functions beyond the protection cut-offs. The overcharge, over-discharge and short-circuit tests run with the protection devices active, so they check the cut-offs, but nothing checks state-of-charge estimation, cell balancing or communication
- An IP rating requirement
- Thermal runaway propagation
- Cycle life
- Connector durability over many mating cycles, which is critical for swap batteries
- Cell traceability
Passing QCVN 31 means the battery survived a defined set of abuse tests. It does not mean the pack is safe and durable for five years of daily use and swapping. These points have to be defined in the manufacturer's or the swap operator's own specification.
Certification and import in practice
Imported batteries must be certified before customs clearance, and domestic batteries before they are sold. Importers apply through the National Single Window. They can choose a certificate for the battery type, valid for 36 months, or a certificate for each shipment. In both cases, they need a passing test report issued to the importer itself.
Manufacturers and importers who plan new models should check whether their application can be filed before 9 October 2026. After that date, all new applications are tested under QCVN 31.
Demand is coming, but more slowly than the headlines said
In July 2025, the Prime Minister's Directive 20/CT-TTg asked Hanoi to remove fossil-fuel motorcycles from inside Ring Road 1 by 1 July 2026, and to extend this to Ring Road 2 from 2028 and Ring Road 3 from 2030. The plan that Hanoi's People's Council adopted in June 2026 is softer. It starts with a pilot and voluntary conversion in the Hoàn Kiếm area in the second half of 2026, adds emissions testing in 2027, and from 2028 to 2029 bars petrol motorcycles that do not meet emission level 3 inside Ring Road 1.
A second rule will matter for swapping and charging. Circular 31/2026/TT-BXD, effective 15 December 2026, adds requirements for electric vehicle charging and battery swap areas in apartment buildings, and gives existing buildings six months to review these areas.
Demand for electric motorcycles in Vietnam will grow step by step, and the safety rules around batteries, charging and swapping are growing at the same time.
What pack makers, importers and swap operators should do now
- Decide for each battery type whether it is removable, and state it in the type documents.
- Run the 2-hour saltwater immersion test on current designs before certification, and check sealing, venting and the position of the BMS board.
- Keep the drop test for fixed batteries too, and a 24-hour water ingress test for both fixed and swappable batteries, as part of your internal design validation standard.
- Add incoming cell inspection and supplier audits, since the regulation no longer tests the cell.
- For swap batteries, define connector durability, BMS communication and traceability in your own specification.
- File applications for models in development before 9 October 2026 if you want them assessed under the old rules.
QCVN 31 sets the minimum. The safety and durability of a swap battery are decided by the specification the manufacturer writes on top of it.
Frequently asked questions
When does QCVN 31:2026/BXD take effect?
On 9 October 2026. It was issued by Circular 13/2026/TT-BXD on 9 April 2026 and replaces QCVN 91:2024.
Is the freshwater immersion test still required?
No. The 24-hour freshwater test is replaced by a 2-hour test in a 3.5% to 5.0% sodium chloride solution. There is only one immersion test in the new regulation.
Do fixed batteries still need a drop test?
Not under QCVN 31. The drop test now applies only to removable batteries. We recommend keeping it for fixed batteries too, as part of the manufacturer's internal design validation standard.
Does QCVN 31 require UN 38.3?
No. QCVN 31 does not reference UN 38.3. However, lithium batteries shipped by air or sea must pass UN 38.3 under international dangerous goods rules, and their package must withstand a 1.2 m drop test.
eMOBINO supports electric motorcycle pack makers, importers and swap operators with pack design reviews, validation plans, cell incoming inspection and supplier audits. If you are preparing a battery for QCVN 31 certification, we can review your design and test plan with you.
Sources
- Ministry of Construction, Circular 13/2026/TT-BXD and QCVN 31:2026/BXD (9 April 2026).
- Ministry of Transport, Circular 48/2024 and QCVN 91:2024 (15 November 2024).
- Ministry of Construction, consolidated text of Circular 54/2024 on import certification of vehicle parts (September 2026).
- Prime Minister, Directive 20/CT-TTg (12 July 2025), and Hanoi People's Council, low-emission zone plan for Ring Road 1 (15 June 2026).
- Ministry of Construction, Circular 31/2026/TT-BXD amending QCVN 04:2021/BXD on apartment buildings (15 June 2026).
- UN Manual of Tests and Criteria, Section 38.3, lithium battery transport tests.
- GB 38031-2025, Electric vehicles traction battery safety requirements.
