ISO 12405 — Standard

About the Standard

Scope title: test conditions for electric vehicle lithium battery packs

ISO 12405 is a standard published by International Organization for Standardization (ISO). The international standards organisation; it publishes the widest body of management system, test method and product standards.

See the other 310 codes from ISO

Coverage areas

What Is ISO 12405?

The ISO 12405 series is the test specification for lithium-ion traction battery packs and systems in electric vehicles. It is not an approval regime; it is a specification defining HOW the measurement is made. Approval runs through UNECE R100 and North American assessment through UL 2580.

The structure of the series has changed over time, and that change often causes confusion in specifications. ISO 12405-1 for high power applications and ISO 12405-2 for high energy applications have been superseded, in respect of performance testing, by ISO 12405-4, which combines them. The current performance reference is PART 4.

Part 3 addresses safety performance requirements. Cell-level testing belongs not to this series but to the IEC 62660 series; the system, pack and cell levels are assessed against separate references and that distinction must be made clear in the supply chain.

The specification examines the battery against THE VEHICLE USAGE PROFILE: power and energy capacity measurements, internal resistance, charge acceptance behaviour, self-discharge, cycle endurance, behaviour after storage and temperature-dependent performance. These are performance items; safety tests appear in a separate part.

The distinction between high power and high energy was the fundamental concept of the series and remains meaningful. A hybrid vehicle battery is a system of small capacity capable of delivering high power; it charges and discharges continuously. A full electric vehicle battery is large in capacity and energy-focused. The two require different test profiles and Part 4 is written to cover both.

Why Does This Standard Exist?

The series arose because the performance of electric vehicle batteries could not be measured comparably. Every manufacturer declared capacity and power by its own method; values measured at different temperatures, different discharge rates and different states of charge could not be compared.

For a battery, capacity is not a single number. The same pack delivers markedly less energy at low temperature; under rapid discharge part of its capacity is inaccessible; as it ages capacity falls. Standardising the measurement conditions was therefore essential for a declaration to be meaningful.

The measurement of INTERNAL RESISTANCE is the most technical part of the series and is very important in practice because it determines the power the battery can deliver. Resistance depends on temperature, state of charge and age; the measurement is therefore made as a matrix and is not reported as a single value.

Merging Parts 1 and 2 had a practical justification. The sharp distinction between hybrid and full electric vehicles blurred: plug-in hybrids require both high power and high energy. Rather than maintaining two separate specifications, a single text was written to cover that spectrum.

Cycle endurance tests are the longest-running part of the series and can take months. They must therefore be planned early in the product development timetable; without cycle life data, a warranty period and a capacity retention claim cannot be supported.

Structure of the Standard

ISO 12405-3
Safety performance requirements; safety behaviour at pack and system level.
ISO 12405-4
Performance testing; it covers high power and high energy applications together and has superseded Parts 1 and 2.
The IEC 62660 series
Cell-level performance, reliability and abuse testing; outside the scope of this series.

Which Products Require It

Traction battery packs for electric and hybrid vehicles
Battery systems and subsystems assessed together with their management electronics
Performance verification in vehicle manufacturer approval files
Batteries for plug-in hybrid and range-extended vehicles
Batteries for heavy commercial vehicles and buses

Related Legislation and Schemes

It is used as performance and safety data in a UNECE R100 type approval file
The ISO 6469 series addresses electrical safety at vehicle level
In North America, UL 2580 is the corresponding assessment standard
On the transport side, UN 38.3 is also required
Battery Regulation (EU) 2023/1542 introduces durability and capacity declaration obligations

How the Assessment Runs

1Scope and application typeWhether the battery is a high power or high energy application and which test set applies are determined.
2Conditioning and reference measurementThe battery is conditioned at a defined temperature and state of charge; the reference capacity and resistance are measured.
3Performance measurementsCapacity, energy, power, internal resistance and efficiency are measured as a matrix at different temperatures and states of charge.
4Endurance testsCycle life and storage (calendar) life tests are carried out; changes in capacity and resistance are monitored.
5ReportingThe measurement conditions, matrix results and endurance trends are reported.

Neighbouring Standards and the Differences

The IEC 62660 series
Cell level. A pack specification does not cover cell testing; the two levels are addressed by separate references.
UNECE R100
A type approval regime. ISO 12405 is a measurement specification and grants no approval.
UL 2580
The North American assessment standard; it focuses on pack/system safety.
The ISO 6469 series
Electrical safety at vehicle level; it addresses the integration of the battery pack into the vehicle.

What the Report Must Contain

To be usable, a report must carry the information below. An incomplete report may not be accepted in the supply chain or in an inspection even when its result is correct.

The part applied (-3 safety, -4 performance) and its edition
Battery description: cell type, configuration, nominal voltage and capacity
Measurement conditions: temperature, state of charge, current rates
Capacity, energy, power and internal resistance matrix results
Cycle and storage life data with trend charts
The conditioning procedure and the reference measurements

Commonly Confused Points

ISO 12405-1 and -2 have been superseded by ISO 12405-4 in respect of performance testing; specifications referring to the old parts must be updated.
A pack specification does not cover cell testing; the cell side is in the IEC 62660 series.
A performance test is not a safety test; the two are addressed in separate parts and both may be required.
Capacity is not a single number; a declared capacity cannot be compared without stating the measurement temperature and discharge rate.
Cycle life tests take months; they must be planned early in the development timetable.
ISO 12405 is not an approval; a type approval regime runs separately for road registration.

Structure of the Code

Published by: ISO
Serial number: 12405
Part: without partition

Codes in the library without release year is kept. The current version changes over time; If the year is specified in your specification, that version is taken as basis, if not specified, the most current version is applied.

Scope

Test
Environmental and Climatic Testing
Vibration and Shock
Battery Testing
Battery Testing
Automotive Testing

Related Tests and Services

Technical Requirements

Standard texts are copyright of the relevant organization; test condition, sample and acceptance criteria cannot be fitted here.

Basis: The ISO 12405-4:2018 scope statement in the ISO catalogue and its merging of Parts 1 and 2; the ISO 12405-3, IEC 62660 and ISO 6469 references; the scope distinctions from UNECE R100 and UL 2580.

Technical requirements specific to your product, once we clarify the scope At offer stage shared in writing.

Relevant Product Groups and Legislation

This code is included in the standard tag of the product pages below.

EV battery

These product pages carry notes for the following markets: European Union, United Kingdom, USA, China. Whether the standard is mandatory in the relevant market varies depending on the product group and the applicable legislation.

Regulations published with this code on the same product pages:

(EU) 2023/1542Batteries RegulationCarbon footprint declaration, recycled content and the battery passport for batteries; the performance class for EV batteries took effect in August 2026.
UN Manual of Tests and CriteriaUN 38.3Transport safety of lithium cells and batteries; the T1–T8 series is applied in the defined order.
(AB) 2018/858Vehicle Type-Approval FrameworkApproval and market surveillance of motor vehicles. The battery system is assessed as part of vehicle type-approval.
UNECE R100UNECE R100Vehicle and battery system approval under requirements specific to electric drivetrains.
2011/65/EURoHSRestriction of hazardous substances in electrical and electronic equipment.

Related Standards

Frequently Asked Questions About ISO 12405

Which part should we apply?

Part 4 for performance and Part 3 for safety performance. If your specification refers to the old Part 1 or 2, it needs to be updated.

We have cell tests — are they sufficient for the pack?

They are not. The cell side falls under IEC 62660 and the pack side under ISO 12405, and pack behaviour depends on the BMS and the mechanical structure.

How should we declare our capacity?

Together with the measurement conditions: at what temperature, at what discharge rate and within what charge window it was measured must be stated.

How long does a cycle life test take?

Depending on the target cycle count and the test rate, it can take months. Accelerated protocols can be used but their relationship to real conditions must be justified.

Frequently Asked Questions

Is this standard mandatory for my product?

Whether it is mandatory depends on the product group, the target market and the applicable legislation. Once you tell us your product and market, we clarify in writing whether this standard is required.

How long does the test process take?

Duration depends on the scope of the standard, the number of specimens and current capacity. The exact duration is shared, together with the specimen and scope details, at the quote stage.

Do you issue certification against this standard?

Which activity is carried out under which accreditation scope is separately confirmed at the application stage. Up-to-date scope information is published on our corporate page.

What happens if the standard I need is not here?

The library is based on a continuously growing inventory. If you cannot find the code you are looking for, you can send it through the quote form; we will assess the relevant scope and get back to you.