1 2 3 4 5 6 7 8 9 10
Document Title UL comments on the draft GTR on electric vehicle safety
Reference Number EVS-03-12
Date
8 Apr 2013
Source(s) UL
Rulemaking Area(s) GTR No. 20 Electric Vehicle Safety
Meeting(s)
Downloads
UNECE server .docx format
Excerpts from session reports related to this document
EVS | Session 3 | 16-18 Apr 2013

OICA prepared a Draft GTR Justification document detailing the technical rationale and justification for the (i) Application/scope and (ii) Requirements of a vehicle with regard to its electrical safety – post-crash (which could also be used as basis for In-use requirement justification). During the meeting OICA read through the most critical items in this document to facilitate open discussion. A brief summary of the main points discussed (as numbered in the Reference document e.g. #3) are made here.

#2 Rationale for low energy criterion:
The US questions the value cited for minimum energy causing a safety concern (i.e. 0.2 J). The IG chairman agreed with OICA to organize a teleconference to address this topic specifically. All member of the IG are welcome to participate.

#3 Rational for physical protection criterion:
The US requested OICA to quantify the likelihood of occurrence of the direct contact scenarios described by NHTSA. OICA will provide more data for this.

#5 Rationale REESS requirements

#5.8 SOC for REESS testing:
Currently proposed by OICA at 50% SOC, Japan made a counterproposal to perform tests at 95% SOC (Reference document – EVS-03-16e.doc). Japan made a presentation summarizing the SOC applied in battery tests in various standards which indicated that 80-100% SOC is commonplace. China and US agreed that 50% SOC is not sufficient. OICA will reconsider this proposal. Japan indicated their presentation would be made available on the IG website.

#5.9 Vibration
The vibration test procedure from UN 38.3 is used by OICA however different values for the vibration profile are used to make it representative of battery real-life application. The US requested more information on how representative this profile is of application in a vehicle and also why a test duration of 3 hours is chosen. OICA will provide data on this.

#5.18 Thermal shock and cycling:
Following discussions OICA will provide data supporting their suggested temperature range i.e. -40 to +60°C, other standards (ISO, SAE) use higher upper temperatures. Questions also arose about the rationale for the number of temperature cycles (only 5), the upper temperature limit at +60°C instead of +80°C and the duration of the observation period. NHTSA research will perform tests starting with 25 cycles – the results will be shared with the IG as far as available.

#5.41 Fire resistance
The US considered the test duration (60 + 70 seconds) is too short to be representative of realistic fire scenario. OICA commented that the duration represents scenario where persons inside a burning vehicle have time to evacuate. The OICA proposal is based on the established UN R34 gasoline pool fire. ALLIANCE only observed bonfire tests where battery underwent a benign controlled burn. NHTSA is sponsoring research on battery fire including gas release analysis and will have the updated information later. Japan commented that an EV would probably have a similar risk in a fire compared to diesel ICE however the risk from high pressure gas (eg in H2 vehicle) is a bigger concern. Discussion on this issue will continue as research data becomes available.

#5.47 External short circuit protection
Discussion arose concerning the chosen resistance of the short (i.e. 5mΩ). OICA will include a rationale for this choice.

#5.50 Over-discharge protection
OICA propose this test with the over-discharge protection system installed in order to demonstrate the functionality of this system. Korea questioned the suitability of this test (discharge down to 25% nominal voltage) for super capacitors or flywheels. The IG will decide what REESS devices will be included in GTR and OICA will then propose any required modifications for tests.
The US questioned the rationale for the 1 hour observation time. OICA enquired as to a counterproposal but this would not be agreed during this meeting.

#5.51 Over-temperature protection
It was questioned why a specific temperature e.g. 60°C or higher is not suggested in this test. OICA indicated that this may be design restrictive but they would consider specifying a temperature.

#5.54 Hydrogen emissions
Japan suggested inclusion of this requirement to cover emissions from aqueous electrolyte (open) type batteries e.g. lead acid. While not currently commonplace this type of battery may be used for traction purposes. OICA will introduce this as part of the draft.
The EU questioned the need for international harmonisation efforts if technology will only be applied in some markets.

Further comments from IG members ensued:
COMMENTS FROM UL on OICA DRAFT (Reference document: EVS-03-12e)
Clarification is required for the definition of (fuel) cell and rupture. OICA will look how terms are used in document and will modify definitions if appropriate.

COMMENTS FROM KOREA on OICA DRAFT (Reference document: EVS-03-13e)
Korea proposed another test procedure for fire resistance which has been applied in Korea since 2009 as an alternative to the test proposed by OICA. OICA will take Korea’s proposal into consideration.

The IG secretary will summarize all comments to the OICA draft into one document. OICA will then address all comments for the next meeting.

The GTR Outline will be used as the basis for the GTR and items proposed by OICA will be incorporated by secretary into the outline when agreed or will be inserted in [square brackets]. OICA requested that their proposal be transformed by the next meeting from an OICA proposal into a Group Document.