Initially only the small lithium ion batteries?i100Wh or less per Section II?jhad to have the Watt-hour rating Mar ed on them. This took effect for batteries manufactured 1 Jan ary 2009 and later. The requirement for these batteries to be Mar ed also originally included an exception in transport up to 31 Dec mber 2010 for those manufactured prior to 2009. The expectation being that these batteries that were not Mar ed would no longer be transported.
The UN Subcommittee who introduced these requirements was then aware that batteries without Mar ing would be transported for some time and that therefore there was no way to differentiate between the larger batteries (more than 100Wh per Section I) which did not require Mar ing and the smaller batteries manufactured prior to 2009. So then the UN Subcommittee introduced Mar ing for the larger lithium ion batteries (more than 100Wh per Section I) with effect 1 Jan ary 2012.
In this way, eventually all lithium ion batteries must be Mar ed with their Watt-hour rating to allow shippers and others in the supply chain to clearly identify what regulatory requirements apply.