Revision 2 of UNECE Regulation No. 100 will impose a number of new tests on manufacturers of rechargeable battery systems found in electric motor vehicles. The tests are intended to ensure the safe operation of rechargeable batteries under anticipated operating conditions, and to provide a greater level of safety for vehicle drivers and passengers. This article summarizes the new testing requirements.
Global standards for motor vehicles and electric vehicles are the responsibility of the World Forum for the Harmonization of Vehicles, a permanent working party (WP 29) under the United Nations Economic Commission for Europe (UNECE). The goal of the Forum is to establish globally harmonized regulations for motor vehicles in order to remove barriers to international trade, promote road safety and protect the environment. The actions of the Forum are based on the so-called 1958 Agreement, under which the European Union and nearly 60 other signatory countries agree to apply a common set of technical specifications to motor vehicles manufactured or sold within their countries, and to allow entry to motor vehicles manufactured in other countries that meet those specifications.
Specific technical requirements are found in approximately 130 separate regulations, addressing vehicle components like lighting and instrumentation, operational characteristics including crashworthiness or environmental compatibility. To demonstrate compliance with applicable regulations, manufacturers submit vehicles and components to an authorized third-party (“Technical Service”) for type approval evaluation. Under the terms of the 1958 Agreement, motor vehicles and components that receive type approval in one signatory country must be accepted for importation, sale or use in all other signatory countries (although a number of non-EU signatory countries are reportedly requiring retesting in laboratories located in their own countries).
UN ECE Regulation No. 100 (also referred to as R100) addresses the safety requirements specific to the electric power train of road vehicles including rechargeable battery systems. Originally published in 1996, the regulation was revised in 2011 to keep pace with new technologies. However, applications for R100 type approval were limited exclusively to entire vehicle assemblies and evaluations of vehicle component safety were conducted as part of a total vehicle assessment and limited in scope. As a result, vehicle manufacturers were also restricted from changing individual systems or components or to substitute components from one sub-manufacturer with those from another, without requiring a new type approval application for the complete high voltage electrical powertrain.
Published in 2013, the second revision of R100 implemented significant changes in the type approval process applicable to motor vehicles and Rechargeable Energy Storage Systems (RESSs). The regulation provided a separate approval path for RESSs (most often, rechargeable battery packs), and introduced a number of tests exclusively applicable to these systems. With the introduction of these new testing requirements, which take effect in July 2014 and become mandatory in July 2016, the responsibility for obtaining type approval for a rechargeable battery may also shift to the RESS manufacturer.
Testing requirements in the second revision of R100
The essential requirements for RESSs in the second revision of R100, classified as Part II requirements, are found in Section 6 of the regulation. Annex 8 provides detailed information on testing procedures specific to RESSs, which include the following:
|Verifies the safety performance of an RESS under vibration conditions similar to those experienced under normal vehicle operations. The device under test is subject to a vibration having a sinusoidal waveform with a logarithmic sweep between 7 Hz and 50 Hz and back to 7 Hz in the span of 15 minutes. This sweep is repeated 12 times for a total test period of three hours.
| Thermal shock and cycling
|Assesses the resistance of an RESS to sudden changes in temperature similar to those experienced in actual environmental conditions. The device under test is stored for at least six hours at 60oC, followed by six hours at -40oC. This cycle is repeated five times, followed by storage of the device at ambient temperatures for 24 hours.
| Mechanical shock
|Verifies the safety performance of an RESS under inertial loads that may occur in vehicle crash conditions. The device under test is accelerated or decelerated at speeds specified in the tables accompanying the Regulation, and the actual gravitational force is compared with the values specified in the tables.
| Mechanical integrity
|Evaluates the safety performance of an RESS under contact loads that might be experienced in vehicle crash conditions. The device under test is crushed between a resistance plate and a crush plate with a specified force, onset time and hold time.
| Fire resistance
|Assesses the resistance of an RESS to exposure from a fire originating outside of a vehicle, to determine whether a driver and passengers have sufficient escape time. The device under test is subject to both direct and indirect exposure to a flame that has been produced by burning commercial fuel.
| External short circuit protection
|Verifies the performance of a device’s short circuit protection system to limit consequences associated with short circuits. The device under test is subject to an intentional short circuit by connecting the positive and negative terminals of the device, using a connection with a specified resistance. The short circuit condition is continued until the function of the short circuit protection can be confirmed, or for at least one hour after the temperature measured on the device casing has stabilized.
| Overcharge protection
|Assesses the performance of a device’s overcharge protection system. The device under test is charged until the device automatically interrupts or limits the charging, or until the device is charged to twice its rated capacity.
| Over discharge protection
|Evaluates the performance of a device’s over-discharge protection system. The device under test is discharged until it interrupts or limits the discharge, or when the device is discharged to 25% of its nominal voltage level.
| Over-temperature protection
|Verifies the performance of a device against internal overheating during operation, even when the device’s cooling function fails. The device under test is repeatedly charged and discharged with a steady current to increase the temperature of cells. The device is then placed in a convection oven or climatic chamber, and the temperature of the oven or chamber is gradually increased to a pre-determined level.
In some cases, testing values that differ from those presented in Annex 8 may be used, for example when a motor vehicle manufacturer presents simulations and results that demonstrate the appropriateness or preferability of an alternative approach.
The impact of second revision R100 testing on RESS and motor vehicle manufacturers
RESS testing requirements under the second revision of R100 are more extensive than previous versions of the regulation, and the responsibility for obtaining type approval might shift to RESSs manufacturers. RESS manufacturers and motor vehicle manufacturers should take steps now to address the new type approval requirements ahead of the July 2016 mandate. However, the regulation’s new approach to type approval may provide manufactures with new market opportunities, since vehicle manufacturers will be able to select type-approved RESSs during the design and development process that best match their specific requirements, or change RESSs in production vehicles without resubmitting their vehicle for a full type review.
The second revision of R100 introduces new testing requirements for manufacturers of rechargeable battery systems for electric vehicles, but also modifies the current type approval scheme, a change that is likely to increase competition in the RESS marketplace. TÜV SÜD can assist manufacturers in the testing and type approval of RESSs and rechargeable batteries for electric vehicles for compliance with the requirements of the second revision of R100 ahead of the July 2016 transition. For more information, contact us at [email protected]