UN Regulation No. 136 (ECE R136)

UN Regulation No. 136 (ECE R136) Uniform Provisions Concerning the Approval of Vehicles of Category L with Regard to Specific Requirements for the Electric Power Train. This is a UNECE type-approval regulation governing the safety of high-voltage systems and rechargeable electrical energy storage systems (REESS) in light electric vehicles. It was adopted under the 1958 Agreement administered by the United Nations Economic Commission for Europe (UNECE) and entered into force in 2016, with Amendment 1 published in February 2023 introducing the overcurrent protection test.

Published by: United Nations Economic Commission for Europe (UNECE), Working Party on Passive Safety (GRSP)

Current edition: Revision 1, Amendment 1 (February 2023) — includes the mandatory Overcurrent Protection Test

Original publication: 2016 (initial adoption under the 1958 Agreement)

Transition deadline: From 1 September 2025, new type-approval applications must comply with Amendment 1; the original version is no longer accepted for new applications.

Scope

ECE R136 applies to all L-category vehicles: two-wheelers, three-wheelers, and lightweight four-wheelers and equipped with one or more electric traction motors, with a maximum design speed exceeding 6 km/h, and not permanently connected to the electrical grid. This covers sub-categories L1e through L7e:

L1e – Two-wheeled mopeds (max 45 km/h, 50 cc equivalent)
L2e – Three-wheeled mopeds with similar power restrictions
L3e – Two-wheeled motorcycles (no speed or power limit)
L4e – Motorcycles with sidecar
L5e – Three-wheeled motor vehicles with higher performance
L6e – Light quadricycles (max 45 km/h, unladen mass up to 425 kg excl. batteries)
L7e – Heavy quadricycles

The regulation covers high-voltage systems and REESS (battery packs/systems). It does not apply to low-voltage starting, lighting, or auxiliary systems, nor to vehicles permanently connected to the grid.

Key Requirements and Test Methods

The regulation comprises two sets of requirements: high-voltage system safety and REESS safety.

High-Voltage System Tests

Withstand voltage test:
- Verifies insulation integrity against electric shock; conducted at voltages above working voltage.
Water resistance test:
- Evaluates protection of high-voltage components against moisture and water ingress in normal operating conditions.

REESS (Battery) Tests

Vibration test:
- Simulates road-induced vibration profiles to verify structural and electrical integrity.
Thermal shock and temperature cycling:
- Subjects the REESS to rapid temperature transitions between hot and cold extremes.
Mechanical drop test:
- Applies to removable battery packs; evaluates durability after a defined drop height.
Mechanical shock test:
- Assesses resilience against external impacts that could occur during normal vehicle use or collision.
Fire resistance test:
- Evaluates the REESS enclosure and safety response under external fire exposure.
External short circuit protection test:
- Confirms that the BMS or circuit protection triggers safely under short-circuit conditions.
Overcharge protection test:
- Verifies that the system prevents charging beyond safe voltage limits.
Over-discharge protection test:
- Checks that discharge is limited before damage to cells or system occurs.
Over-temperature protection test:
- Validates that thermal management and protective cut-offs function under elevated temperature.
Overcurrent protection test (Amendment 1, 2023):
- A newly mandatory test requiring the system to trigger effective protective measures when subjected to abnormal high-current conditions. Mandatory for new applications from 1 September 2025.

Certification and Regional Recognition

ECE R136 type approval is granted by a national type-approval authority in a Contracting Party to the 1958 Agreement and is mutually recognised by all other Contracting Parties. Key markets requiring ECE R136 compliance include:

European Union: mandatory for L-category electric vehicles under EU type-approval (Regulation 168/2013)
United Kingdom: retained as part of UK UNECE type approval post-Brexit
Japan, Australia, and other UNECE 1958 Agreement Contracting Parties

Manufacturers seeking EU market access for electric e-bikes, scooters, mopeds, and light quadricycles must demonstrate compliance with ECE R136 (and, for REESS cells, potentially also EN 50604-1).

Related Standards

IEC 62133-2 – Safety requirements for portable sealed secondary lithium cells and batteries; relevant where individual cells within the REESS are tested to a cell-level standard.
IEC 62619 – Safety requirements for secondary lithium cells and batteries for use in industrial applications.
UN 38.3 – Transport testing for lithium batteries; required for shipping batteries used in L-category vehicles.
EN 50604-1 – European standard for secondary lithium batteries used in light EV applications; complements ECE R136 at the battery pack/system level for EU market access.
ECE R100 – Safety requirements for battery electric vehicles of category M and N (passenger cars and light commercial vehicles); covers heavier EVs beyond L-category.
EU Battery Regulation (2023/1542) – EU regulation covering the entire battery lifecycle including LMT (light means of transport) batteries.

Disclaimer: This page is not a definitive guide, just an indication and it is important that you always go back to the source for legislation.