Rechargeable power anywhere

Balancing power supplies and growing digital needs

By Morand Fachot

Secondary batteries, which can be recharged, unlike their primary counterparts, offer the greatest flexibility for many applications, whether mobile or stationary. They make up the fastest growing segment of the battery market and are rapidly evolving as new materials are introduced. This expansion is well supported by the work of IEC TC (Technical Committee) 21: Secondary cells and batteries.

Lead-acid car battery Lead-acid car battery

Enjoying a second youth

Secondary or rechargeable 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. They are not new: the best known and oldest types of rechargeable battery, of the lead-acid variety, date back to the 1860s. They are still widely used, mainly in the automotive industry, where they are known as SLI (starting, lighting, ignition) batteries. They account for about 20% of total battery sector revenue and about a third of the secondary battery market.

Lead-acid batteries are also used in forklifts for materials handling, in cleaning machines and in wheeled mobility applications including golf carts and wheelchairs. These batteries also hold a solid position in the stationary domain, where they are used for EES (Electric Energy Storage): balancing supply from renewable sources, providing backup power and meeting off-grid electric power needs in emergencies. They are unlikely to be replaced at any time in the near future in these domains as they are a well-tried and low-cost option.

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 type. They have been pulled by growing sales of EVs (electric vehicles) and e-bikes of various kinds and the rapid global expansion of personal mobile entertainment, communication and computing devices, including mobile phones, digital cameras, personal entertainment systems 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.

TC 21 focuses predominantly on safety: risks created by electrochemical elements and electricity from high voltage and current, which can have potentially hazardous consequences.

Comprehensive TC work across many domains

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 standardizing application-oriented systems using secondary cells and batteries".

TC 21 has prepared numerous International Standards covering requirements and tests for SLI, RES (renewable energy storage) and aircraft batteries, as well as 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 battery, the TC's work naturally extends to International Standards for performance, reliability, abuse testing and dimensions for these 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 International 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 the committees’ 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, TC 21 and SC 21A maintain liaisons with many other IEC TCs. They include TC 9: Electrical equipment and systems for railways; TC 18: Electrical installations of ships and of mobile and fixed offshore units;TC 22: Power electronic systems and equipment; TC 69: Electric road vehicles and electric industrial trucks; TC 82: Solar photovoltaic energy systems; TC 88: Wind turbines; TC 108: Safety of electronic equipment within the field of audio/video, information technology and communication technology and TC 116: Safety of motor-operated electric tools. The TC also maintains liaisons with other organizations 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, as well as of Electrical Energy Storage needs for the renewable energy sector, smart grid applications and the rapid growth of the portable devices market, points 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/SC 21A will ensure that equipment manufacturers using secondary batteries have safe and dependable products available, and will continue to prepare new and update existing International Standards in a burgeoning sector.

Lead-acid car battery Lead-acid car battery
Rechargeable NiMH penlight batteries and charger Rechargeable NiMH penlight batteries and charger
tc-1_laptop_battery_lrg Li-ion laptop battery