Background

As early as July 2023, at the 62nd session of the United Nations Economic Subcommittee of Experts on the Transport of Dangerous Goods, the Subcommittee affirmed the work progress made by the Informal Working Group (IWG) on the hazard classification system for lithium cells and batteries, and agreed with the IWG’s review of the Regulations Draft and revise the hazard classification of the “Model” and the test protocol of the Manual of Tests and Criteria.

Currently, we know from the latest working documents of the 64th session that the IWG has submitted a revised draft of the lithium battery hazard classification system (ST/SG/AC.10/C.3/2024/13). The meeting will be held from June 24 to July 3, 2024, when the subcommittee will review the draft.

The main revisions to the hazard classification of lithium batteries are as follows:

Regulations

Added hazard classification and UN number for lithium cells and batteries, sodium ion cells and batteries

The state of charge of the battery during transportation should be determined according to the requirements of the hazard category to which it belongs;

Modify special provisions 188, 230, 310, 328, 363, 377, 387, 388, 389, 390;

Added new packaging type: PXXX and PXXY；

Manual of Tests and Standards

Added test requirements and classification flow charts required for hazard classification;

Additional test items:  

T.9：Cell propagation test

T.10：Cell gas volume determination

T.11: Battery propagation test

T.12: Battery gas volume determination

T.13: Cell gas flammability determination

This article will introduce the new battery hazard classification and testing items added in the draft.

Divisions according to hazard categories

Cells and batteries are assigned to one of the divisions according to their hazard properties as defined in the following table. Cells and batteries are assigned to the division which corresponds to the results of the tests described in the Manual of Tests and Criteria, part III, sub-section 38.3.5 and 38.3.6.

Lithium cells and batteries

Sodium ion batteries

Cells and batteries not tested according to 38.3.5 and 38.3.6, including cells and batteries that are prototypes or low productions runs, as mentioned in special provision 310, or damaged or defective cells and batteries are assigned to classification code 95X.

Test Items

In order to determine a specific categorization of the cell or battery, 3 repetitions of the tests corresponding to the categorization flowchart shall be run. If one of the tests cannot be completed and makes the hazard evaluation impossible, additional testsshall be run, until a total of 3 valid tests are completed.The most severe hazard measured over the 3 valid tests shall be reported as the cell or battery test results.

The following test items should be conducted to determine a specific categorization of the cell or battery:

T.9：Cell propagation test

T.10：Cell gas volume determination

T.11: Battery propagation test

T.12: Battery gas volume determination

T.13: Cell gas flammability determination (Not all lithium batteries exhibit flammability hazard. Testing to determine gas flammability is optional for assignment to either divisions 94B, 95B or 94C and 95C. If testing is not conducted then divisions 94B or 95B are assumed by default.)

Summary

The revisions to the hazard classification of lithium batteries involve a lot of content, and 5 new tests related to thermal runaway have been added. It is estimated that it is unlikely that all of these new requirements will pass, but it is still recommended to consider them in advance in product design to avoid affecting the product development cycle once they pass.