SGS Discusses the New UN 38.3 Transport Test Requirements for Lithium Cells and Batteries

UN Transport Tests form the basis for many if not all regulations regarding the transportation of lithium cells or batteries

Lithium cells and batteries have to undergo so called "UN Transport

Tests" before they are eligible for transport. Section 38.3 of the
"Recommendation on the transport of dangerous goods, Manual of Test
and Criteria" (UN ST/SG/AC.10/11) describes the required testing
procedures. Latest amendments to the section concern certain
requirements for lithium cells and batteries and these changes become
effective in January 2013.

With the increasing importance of lithium based energy storage for everyday life applications
as well as for e-mobility, the importance of the UN Transport Tests is destined to increase as
well. UN Transport Tests form the basis for many if not all regulations regarding the
transportation of lithium cells or batteries. Only if the required set of tests has been passed
and if some further requirements are fulfilled (especially for air transport further restrictions
apply) the lithium cells or batteries may be offered for transport without the precautions
otherwise required for the transportation of dangerous goods.

The tests are specified in section 38.3 of the "Recommendation on the transport of
dangerous goods, Manual of Test and Criteria" (UN ST/SG/AC.10/11). The currently effective
revision is Rev 5. An amendment to Rev 5 (Amd 1) has already been published. This is
destined to become effective in January 2013 without further changes in section 38.3.

With the Rev 5 Amd 1 some of the requirements for lithium cells and batteries will change.
Most notably the requirement for a re-test has been somewhat relaxed, a break off from the
housing during a test does not necessarily constitute a failure anymore, component cells
need to also pass T.8, the thermal test has been relaxed (from 75 °C to 72 °C), the vibration
test has been relaxed for large batteries (2 gn instead of 8 gn) and a new Crush Test
replaces the Impact Test for most cell types.

A number of more subtle changes have been made that, while seeming unimportant to
many, may well have an impact on some products. The following points are a selection of the
changes in the new revision, given in the sequence of their appearance in the specification
(not weighted for their supposed importance).

Scope of UN 38.3

Section 38.3 now starts with a summary of which type of primary/secondary cell/battery shall
be subjected to which tests. While it does not contain requirements that are not also listed
elsewhere, the new overview makes things much clearer.

Criteria for a Re-Test

If cells or batteries differ from a tested type by: […]

• Old: (c) A change that would materially affect the test results.
• New: (c) A change that would lead to failure of any of the tests.

A foreseeable small influence on the test results is not a criterion for a re-test anymore. Only
if a failure of at least one of the tests seems possible a re-test is required. A list of examples
of changes that may lead to a re-test is given.
Definition of Battery

• Old: Battery means one or more cells …
• New: Battery means two or more cells …

A long running source of confusion has been clarified. A one cell battery shall be regarded
and tested as a cell not as a battery. Although a rechargeable single cell battery with
overcharge protection shall additionally be subjected to T.7 which is otherwise reserved to
rechargeable batteries (not cells).

Definition of Large/Small Cell

• Old (large): For lithium metal cell if lithium content of the anode, when fully
charged, is more than 12 g. For lithium ion cell if the watt-hour rating is more
than 150 Wh. Otherwise the cell is small.
• New (large): If gross mass is more than 500 g. Otherwise the cell is small.
Similar to the change of the definition for a large/small battery between Rev 4 and Rev 5 the
definition of a large/small cell now refers to the gross mass and gives an easier to handle
criterion.

Definition of Leakage

Old: the escape of material from a cell or battery.
New: the visible escape of electrolyte or other material from a cell or battery or the loss of
material (except battery casing, handling devices or labels) from a cell or battery such that
the loss of mass exceeds the values in Table 38.3.1.
Noteworthy are the listed exceptions. A break off from the battery casing is not necessarily a
failure criterion anymore (it may still be a disassembly or rupture and thus a failure though).
Care must be taken that any broken or fallen off parts are collected and assigned to the
individual sample where they came from, before the latter are weighed to determine the
mass loss.

Another rare but real exception would be that a battery releases enough moisture from its
plastic or foam rubber housing during the thermal test (T.2) to fail the mass loss limit. Since
this is not leakage anymore, it is no longer a failure criterion. However, it will be up to the
manufacturer to prove that the mass loss originates from the housing and not from another
part of the battery. It would probably be an open question to which extent a foam rubber layer
inside a plastic housing is to be regarded as part of the battery casing or not.

Mass Loss Limit of Batteries

The mass loss limit has been relaxed for cells or batteries with a mass 5 g less or equal M
less or equal 75 g

• Old: 0.1 %
• New: 0.2 %

Number of Test Samples

T.6: The special requirement for ten prismatic cells to be tested for T.6 (as opposed to five
for other cells types) has been deleted. It is obsolete with the below mentioned Crush Test.
T.8: The test is now explicitly also required for component cells. Thus, now T.6 (as already
before) and T.8 are the (only) two tests that need to be performed on cells, if these are
directly assembled into batteries and not transported separately.

(f): The special relaxed requirement for certain battery assemblies applies only, if they are
made up of already successfully tested individual batteries. Relaxed requirements for
assemblies made up of already successfully tested cells are not available.

No Mass Loss Requirement

The explicit "no mass loss" requirement for the tests T.1 to T.4 has been deleted. However,
since it is now included in the definition of "Leakage" is will be as valid as before in most
cases (see also Definition of Leakage" above).
Test T.2 Thermal Test

The upper temperature requirement has been relaxed and the specification of the number of
cycles has been clarified.

• Old: upper temperature 75 °C
• New: upper temperature 72 °C
• Old: This procedure is to be repeated 10 times
• New: This procedure is to be repeated until 10 total cycles are complete

Test T.3: Vibration

For large batteries (greater or equal 12 kg) the peak acceleration is relaxed to 2 gn. For all
other samples it remains at 8 gn.

• Old (for all samples): 8 gn
• New (for large batteries only): 2 gn; (for all other samples): 8 gn

An explicit statement has been added that the requirements have to be fulfilled "during the
test and after the test", although no indication is given for how long after the test the samples
need to be monitored. The voltage requirement (not less that 90 % after the test) is now
stated more precisely to apply "directly after testing in its third perpendicular mounting
position".

This has three implications: the perpendicular z-axis shall be tested last, the voltage only
needs to be measured after the third axis (not after the first and second) and the voltage
needs to be measured immediately after the test (not e.g. on the next day after a night test).
Tests T.5, T.7 and T.8

Clarification that the requirements (no disassembly, no rupture, no fire) have to be fulfilled
also during the test and not just within six hours after the test.

Test T.6: Impact/Crush

A new Crush test was added replacing the Impact Test for most cells. The Impact Test has
been clarified.

• Old: Impact test for all samples
• New: Impact Test only for cylindrical cells with > 20 mm diameter, Crush Test for all other
types of cells
• New: Crush Test: max. force of 13 kN between flat surfaces.
• New: Impact Test: The bar placed across the sample is now specified to be of type 316
stainless steel

The complete Rev 5 of the Manual of Tests and Criteria as well as the Amd 1 are available
for free download from the UNECE web page.

About SGS Electrical and Electronics Services
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