1 6th wrbrf 2015 berlin, march 23-24 2015 review of changes voted to section 38.3 of the un manual...

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6th WRBRF 2015Berlin, March 23-24 2015

Review of changes voted to Section 38.3 of the UN Manual of Tests & Criteria (INF 11.)

UNSCETDGGeneva, Dec. 1rst, 2014

Claude CHANSONPPT 5.

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Content: 6 proposals of modification have been adopted

Proposal 1. Add a § (f) to § 38.3.2.2.

Proposal 2. Modify § 38.3.3.

Proposal 3. Modify paragraph 38.3.3. (g)

Proposal 4. T4 shock test change. Option 1

Proposal 5. T5 Short Circuit

Proposal 6. Change in SP188.

7- First Informal WG, Brussels: Short circuit test request from DOT/PHMSA

1- Testing requirements of large format Lithium-batteries

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PROPOSAL 1

38.3.2.2 Note Add the following text

“f) For batteries which are to be tested according to T.4 with a peak acceleration less than 150 gn, a change in the mass which could adversely impact the result of the T.4 test and lead to a failure. “

Justification will be presented with the discussion on T4 , page 13.


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Cells tested Cells tested+ batteries tested

Cells tested + batteries tested+assembled batteries tested

Cells tested + batteries tested + ass. Batteries specified

12 kg limit

6200 Wh limit

Justification for PROPOSAL 2.

1- The objective of the test of large batteries that are assembled from batteries is to check the quality of the mechanical assembly (tests T3 vibration, T4 shock) or electrical protections (test T5 short circuit and T7 overcharge when applicable).

2- These protections have already been tested for new cells and batteries (not yet assembled in the final battery)

3 –Batteries of the assembly have already been tested after 25 cycles. Consequently, the 25 cycles requirement are not necessary for the testing of the mechanical assembly.

4 - Realizing 25 cycles on a large battery requires specific equipment (charging and discharging systems adapted to the high capacity and/or high voltage of the battery) which may not be available in many tests facilities.

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PROPOSAL 3. Modified wording of parag. 38.3.3.g.Justification: the text should describe the risks to prevent, rather than recommend means to prevent risks.


3- Proposals for changes in T4 shock test.

Test procedure of Test 4 : shock test

1. small batteries : • peak acceleration of 150 gn

• pulse duration of 6 milliseconds.

2. large batteries (gross mass greater than 12 kg), • peak acceleration of 50 gn• pulse duration of 11 milliseconds.

ISSUES:-1- The constant acceleration requirement 50 gn should not intend to impose excessively large forces to the large batteries (such as hybrid automotive type): currently there is for example for a 70 kg battery a 30 000 N force required to achieve the 50gn acceleration .

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PROPOSAL 4. OPTION 1.

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2- A strong discontinuity is introduced in the test between a battery with a weight of 11.99 kg at 17k N (150 gn) and a battery with a weight of 12.01 kg battery at ~6k N .


Discussion/ Rationale:

-Generic principle to avoid excessive increase of the force and discontinuity : test with a constant energy shock .

- The consequence is a continuous change in the peak pulse acceleration and duration according the battery weight.

-Other approach: replacement of the shock test by a drop test. - Finally not agreed, due to the potential difficulties for the control of

the specification and of the realization of the test. (reproducibility potential issues)

- But this test provides a peak acceleration change according weight considered as more representative: it has been agreed to take it in account.

=> A rationalized approach is proposed, adjusting acceleration based on constant energy and pulse duration for all battery weights.

The pulse duration of 6 ms for small batteries and 11 ms for large batteries is maintained.

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Proposal 4 (option 1)

A formula allowing the calculation of the peak acceleration is provided

And is applied for constant energy of 12kg, 50gn shoc

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Battery Minimum peak acceleration Pulse duration Small

batteries 150 gn or result of formula

whichever is smaller

6 milliseconds

Large batteries

50 gn or result of formula

whichever is smaller

11 milliseconds

𝑃𝑒𝑎𝑘 𝐴𝑐𝑐𝑒𝑙𝑒𝑟𝑎𝑡𝑖𝑜𝑛 (𝑔𝑛) = ඨ൬𝐸𝑛𝑒𝑟𝑔𝑦 ሺ𝑗𝑜𝑢𝑙𝑒ሻ∗𝜋2 2 𝑥 𝑚𝑎𝑠𝑠 ሺ𝑘𝑔ሻ∗𝑃𝑢𝑙𝑠𝑒_𝑇𝑖𝑚𝑒(sec) 2൰ 9.81 𝑚/𝑠𝑒𝑐2

Proposal 4 (option 1): Based on the new definition, the energy applied for the shock test is constant, and the forces are not increasing to excessively large values

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Proposal 4 (option 1):

An illustration of the corresponding acceleration is shown below

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Batteries ≤ 12.0 kg Batteries > 12.0 kg

adjusting acceleration based on constant energy and pulse duration for large batteries only.

Justification: the scope of the working group is only large batteries.

- the small batteries test is maintained at constant acceleration 150 gn.

- The discontinuity between the small and large batteries is maintained.

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PROPOSAL 4. OPTION 2.


Issues and proposal for change of 38.3.2.2 (c):-If application of the proposed change => need to indicate changes in weight/mass triggering a new test.-No indication available in the present text, relative to the mass variation inside a design type. This point was not easy to define.

By reference to the sub paragraph 38.3.2.2 (c), “A change that would lead to failure of any of the tests, » the change of design type has been defined by reference to the test result:

Proposal for 38.3.2.2 (c) (Proposal 1)

Add the sub paragraph:“f) For batteries which are to be tested according to T.4 with a peak acceleration less than 150 gn, a change in the mass which could adversely impact the result of the T.4 test and lead to a failure. “

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5- Proposal for changes in T5 short circuit test

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The cell or battery to be tested shall be temperature stabilized so that its external case temperature reaches 55 +/- 2 °C and then the cell or battery shall be subjected to a short circuit condition with a total external resistance of less than 0.1 ohm at 55 +- 2 °C. This short circuit condition is continued for at least one hour after the cell or battery external case temperature has returned to 55 +/- 2 °C.

Requirement: Cells and batteries meet this requirement if their external temperature does not exceed 170 °C and there is no disassembly, no rupture and no fire during the test and within six hours after the test.

PROPOSAL 5.Current text

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Case 1: large battery test: fuse is opening


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Case 2: large battery test: fuse is not opening


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ISSUES

•Tolerance for the temperature +55°C (+/-2°C) too tight :

• Example: Thermal sensors at +/-2°C for temperature regulation, will generate larger tolerance on the battery.

• In several standards +/-4°C rather than +/-2°C• +/-2°C is a constraint for the test equipment

•Time of observation after the maximum peak temperature. The cooling time for large batteries can be very long, depending on their thermal insulation. Once the surface temperature is decreasing, for a long time, observation time has no more technical utility.

•maintaining the battery inside the oven during the short circuit test makes the test unpractical: the temperature specification should describe the stabilized internal battery temperature only, before starting the test. The critical point to guarantee is the homogeneous temperature when the test is launched. Once the test is started, the possible temperature change induced by the short circuit is much faster than the effect of external cooling.


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Proposal of case A


• Comments from last SCTDG meeting

• Measuring on the external case cannot say if it is homogeneous: other place for measurement?

• Internal measurement would interfere with the design. It is not feasible. But homogeneity can be controlled through minimum time and/or surface temperature stabilization. Add ”for a minimum time” in the text.

• Is it a risk of fooling the test, as the ambient temperature is not mentioned when the short circuit test is started?

• Because the temperature is homogeneous when the battery is removed out of the thermal cabinet, then the surface temperature will be the first cooling place of the battery. Consequently, as the surface temperature is specified, there is no risk to fool the test. No text change needed.

• Propose for simplification to remove the part of the sentence about « temperature re-increase«.

• Agreed20


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•Amendment Proposal: for §38.3.4.5.2 Test procedure.


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6- Proposal for changes in SP188

PROPOSAL 6.

Justification: clarify in the UN Model Regulation that single cell batteries are cells for purposes of quantities permitted per package and for hazard communication.

Add the following text to the end of SP188

“A single cell battery [as defined in the Manual of Tests and Criteria Part 3, Section 38.3] is considered a “cell” and shall be transported according to the

requirements for “cells” for the purpose of this special provision.”

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7- First Informal WG, Brussels: Short circuit test request from DOT/PHMSA

DOT considere a newshort circuit test is necessary•“None of the ISC screening methods can address the basic concern on IS prevention.•No recommendable test methods for preventing occurrence of ISC can be identified from literature search”

DOT proposes an indentation test“It is important to test for the desired mechanical properties of the separator membranes to mitigate the occurrence of internal short-circuiting and thermal runaway”.

The WG could not come to a consensus as to whether a new test method for the MT&C was necessary: UNSCTDG notification

1 6th wrbrf 2015 berlin, march 23-24 2015 review of changes voted to section 38.3 of the un manual...

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