Lithium-ion batteries: benefits, risks and regulation

Lithium-ion batteries are widely used in all manner of electrical and electronic equipment nowadays: smart phones, laptops, tablets, power tools, medical devices and mobility equipment to name but a few. Usage is also poised to grow exponentially as electric vehicle technology develops and the global market for such vehicles expands.

As to why lithium-ion batteries are favoured by equipment manufacturers, the short answer is that they offer various benefits, not least a high energy density compared to other battery types as is shown in the table.

Further benefits include:

• That, for the same usable capacity as lead acid batteries, lithium-ion batteries are typically 80% lighter.
• They charge more rapidly than other battery types: circa 90% within one hour, 100% in three hours.
• They have relatively long service lives compared to other battery types, circa 2,000-3,000 cycles.
• Unlike lead-acid batteries which are susceptible to sulfation (i.e. the crystallisation of electrically insulating lead sulfate) that affects their ability to charge, lithium batteries do not suffer from this type of effect. Chemically, they are of different composition.
• They have low self-discharge rates compared to other battery types.

However, the use of lithium-ion batteries in electrical and electronic equipment is not without risk.

Samsung’s experience in using irregular-sized lithium-ion batteries in its Galaxy Note 7 smartphone illustrates the point: the cause of several fires, the smartphone was subject to a global recall and, ultimately, discontinuation. The overall cost to Samsung was estimated at over $5bn – although that does not account for reputational damage.

Safety and reliability risks may come about from the battery cell itself, but also when the cell is integrated into a battery pack and, subsequently, into the equipment that the battery is to power.

As most manufacturers of electrical and electronic equipment source rather than make the lithium-ion batteries incorporated into their products, it is important that they understand something of battery testing and production to ensure supplies are safe and of good quality.

With respect to testing, Section 38.3 of the UN Manual of Tests and Criteria is relevant. Testing against this is mandatory for transport of lithium metal and lithium-ion cells and batteries by all common commercial modes (e.g. air, haulage) in almost every global locale.

Critical control points

The test regime is sometimes known as T1-T8 testing and covers eight key variables: altitude, thermal cycling, vibration, mechanical shock, short circuit, impact/crush, overcharge, and forced discharge.

Various samples are required, with some cells and batteries subject to 50 charge-discharge cycles for aging and others tested as new.

For equipment manufacturers, it is well worth enquiring into T1-T8 testing with battery suppliers: has it been done and can evidence of successfully tested cells and battery packs be provided? If not, it may be as well to turn to other battery suppliers to see what they can offer.

RINA has looked into the battery manufacturing process before now and is aware of critical control points that can affect safety and reliability.

For equipment manufacturers, RINA recommends getting to know the process, with key factors being the quality (and quality control) of the starting materials, the control of thickness in the coating process, steps taken to avoid particulate contamination, and humidity control.

Beyond T1-T8 testing, equipment manufacturers must also be mindful of the regulation affecting battery-powered products in the markets they are selling into. For example, EU regulation spans safety as well as environmental legislation, some of which necessitates CE marking.

There is a specific EU Batteries and Accumulators Directive (2006/66/EC), although this is not concerned with safety per se but environmental protection and spans substance restrictions, capacity marking, battery removal, labelling and end-of-life obligations.

Equipment manufacturers may also wish to familiarise themselves with relevant safety standards, particularly when these can be used to demonstrate the meeting of requirements found in safety legislation. In Europe, EN 62133-2 is a key standard since this relates to portable sealed secondary cells (lithium-ion batteries are “secondary” as they are rechargeable).

Adhering to the standard means subjecting a sample battery to various tests, among them external short circuit, drop and thermal abuse.

Transportation regulation

Finally, transportation regulation. This is separate to product regulation, with different international bodies defining obligations depending on the mode of transport (e.g. IATA for air, ADR for road).

In the case of IATA, all lithium batteries constitute types of dangerous goods meaning that those responsible for shipping such batteries (including equipment manufacturers) need to meet IATA Dangerous Goods Regulations.

Depending on any given consignment, obligations can include preparing accompanying documentation, using particular types of packaging and affixing identification labels to this packaging, and keeping within a restriction – by weight or else the numbers of batteries/cells being flown.

To realise the benefits of lithium-ion batteries, then, equipment manufacturers should heed the risks while ensuring regulatory requirements are met. For further information, please contact productregulation@rina.org

The authors will be presenting on this topic at RINA’s EEE & the Environment Conference on 14-15 November 2018 at the Hilton London Heathrow Airport Hotel (T4). Details on the conference can be found at: https://www.edifgroup.com/training/conference