Rechargeable power anywhere

Issue 39 – June 2012

Energy on tap

Instant access to electricity anywhere, at any time, is becoming more and more important. In many conditions and locations, only batteries can provide this access. Secondary batteries, which can be recharged, offer the greatest flexibility for many applications, whether mobile or stationary. They make up the fastest growing segment of the battery market and are evolving with the introduction of new materials. This expansion is well supported by the work of IEC TC (Technical Committee) 21: Secondary cells and batteries.

Not new, but still current

Secondary batteries make up the lion's share (over 80%) of the global battery market and are expected to represent a value of some USD 61 billion in 2015. Being rechargeable, they are irreplaceable for many applications, whether these are mobile or stationary.

The best known and oldest type of secondary battery is of the lead-acid type, which dates back to the 1860s. It is made up of lead and lead dioxide plates submerged in an electrolyte solution containing sulphuric acid. It is still widespread and represents about a third of the secondary battery market.

Irreplaceable for mobile and stationary use

Lead acid batteries are mainly used in the automotive industry, where they are known as SLI (starting, lighting, ignition) batteries and represent about 20% of the total revenue of the battery sector. Other uses include deep-cycle batteries for traction such as forklifts, material handling, and cleaning machines as well as for wheeled mobility applications including golf carts and wheelchairs, and stationary use for EES (Electric Energy Storage) for renewable energies, power backup, and to provide off-grid electric power in emergencies.

Lead acid batteries hold a solid position in the automotive and stationary domains where they are unlikely to be replaced at any time in the near future as they are a well-tried and low-cost option. Overall, lead acid batteries make up a third of the total battery market.

Modern chemistries

More recent electrochemical systems are also used in the production of secondary batteries, in particular of the dry-cell type. The most common are NiCd (nickel cadmium), NiMH (nickel metal hydride), Li-ion (lithium ion) and Li-ion polymer.

Nickel based batteries, available in small form shapes, are used in applications such as power tools, electric toys, portable electronic devices, and hybrid electric vehicles. These batteries make up around 5% of the battery market.

The most widespread recent rechargeable batteries are of the Li-ion sort, pulled by growing sales of EVs (electric vehicles) and e-bikes of various kinds and the global rapid expansion of personal mobile entertainment, communication and computing devices, such as mobile phones, digital cameras, personal entertainment, and portable computers.

Li-ion is the battery of choice for electronic consumer products. Its share of the market is comparable to that of lead acid batteries but is growing faster.

Safety represents an important area of work for TC 21. The attention of TC21 is mainly focused on safety risks due to electrochemical elements and electricity from high voltage and current, which can have potentially hazardous consequences.

Comprehensive TC work across many domains

IEC TC 21 was established in 1931 'to prepare product standards for all secondary cells and batteries, irrespective of type, chemistry or application. The requirements cover all aspects: safety installation principles, performance, dimensions, labelling. All electrochemical systems are considered'.

Its SC (Subcommittee) 21A was established in 1965 'to prepare product standards for all sealed and vented secondary cells and batteries containing alkaline or other non-acid electrolytes'.

The remit of both TC 21 and SC 21A includes 'supporting other technical committees standardising application-oriented systems using secondary cells and batteries'. As such they maintain liaisons with many IEC TCs.

TC 21 has prepared numerous Standards covering requirements and tests for SLI, RES (renewable energy storage), aircraft, stationary, and traction lead-acid batteries for road vehicles, locomotives, industrial trucks, and mechanical handling equipment.

With the development of EVs and the adoption of hybrid and plug-in hybrid Li-ion batteries, which are seen as one of the most promising types of secondary batteries, the TC's work naturally extends to Standards for performance, reliability, abuse testing, and dimensions for such batteries.

In the transportation domain, TC 21 has also prepared International Standards for aircraft batteries, which must meet specific and rigorous requirements in terms of their design, construction, and performance.

With the expansion of the renewable energy sector, the need to store energy for balancing power generation and distribution during peak periods has led to additional demand for batteries. TC 21 prepares Standards for secondary cells and batteries for renewable energy storage (wind, photovoltaic, etc.) covering 'In' and 'Off' grid applications.

In addition, the TC has announced that it will 'continue to monitor the rapid development of various new chemistries in the field of Li-ion batteries'.

System approach

TC 21 and SC 21A work closely with TC 35: Primary cells and batteries, as some Standards apply across their respective areas of work.

Since secondary batteries are used in a number of sectors such as air, road, rail, and sea transport, electronics systems, renewable energy, and electrical energy storage, TC21 and SC21A maintain liaisons with many other IEC TCs. They include TC9: Electrical equipment and systems for railways; TC 18; Electrical installations of ships and of mobile and fixed offshore units; TC22: Power electronic systems and equipment; TC69: Electric road vehicles and electric industrial trucks; TC82: Solar photovoltaic energy systems; TC88: Wind turbines; TC108: Safety of electronic equipment within the field of audio/video, information technology, and communication technology; and TC116: Safety of motor-operated electric tools. The TC also maintains liaisons with other organisations, such as ISO (International Organization for Standardization) especially for electro-mobility applications.

Market trends and objectives

The expansion of the transport sector, in particular in terms of EVs, e-bikes, mobility scooters, and buses and of Electrical Energy Storage needs for the renewable energy sector, smart grid applications, and the rapid growth of the portable devices market point to the continued healthy development of the secondary battery sector, which is expected to grow by 68% between 2009 and 2015.

To sustain that growth, IEC TC 21 / SC21A will support the work of other IEC TCs and ensure that equipment manufacturers using secondary batteries can rely on safe and dependable products, and will continue to prepare new and update existing Standards in a burgeoning sector.

Reproduced from IEC newsletter, e-tech, May 2012

Published in energy.