TC work underpins mobile and stationary energy storage


By Morand Fachot


Johnson city AES battery storage 8 MW Li-ion battery grid storage system in New York State (Photo: AES Corporation)

Different applications, similar restricting issues

As IT and CE mobile and wearable devices employ ever more advanced processors, displays and audio systems and offer connectivity to an ever growing range of wireless networks and other devices, they are becoming more and more power hungry.

Likewise, the wider adoption of full or hybrid electric drives in electric vehicles (EVs) is seen as hinging on the availability of more advanced batteries (and charging systems), which will allow them to overcome the limitations of range and charge they currently face. 

Different chemistries for different applications

Today’s batteries for mobile applications are based mainly on Li-ion (lithium-ion) chemistry, which offers the key advantage of being able to store large amounts of energy in comparatively light, compact and purpose-made packages. However, while these batteries may provide a reliable power supply, they can no longer keep up with the growing demands placed on them in their current form. 

New trends in automotive applications

Although attention has been focusing on storage for mobile applications for a few years, trend in the automotive sector are no less interesting.

EVs rely extensively too on Li-ion batteries, but may use also nickel-metal hydride batteries. As for vehicles powered by internal combustion engines (ICEs), they depend on rechargeable sealed lead-acid starter batteries, increasingly of the valve-regulated type (VRLA).

International Standards for batteries used in automotive applications, including "for the propulsion of electric road vehicles" are developed by IEC TC 21 and its Subcommittee (SC) 21A: Secondary cells and batteries containing alkaline or other non-acid electrolytes.

As car manufacturers are striving to manufacture cars that will meet tighter emission laws in many countries and regions from 2025-2030, some are now prioritizing so-called 48 V mild hybrids as an interim solution before achieving pure electrification of vehicles. Mild hybridization relies on lithium-ion batteries and consists in adapting 48 V devices and interconnects to existing ICE powertrains. This technology has already been tested for a number of years and offers, among many others, the following benefits, according to IDTechEx Research and manufacturers' data:

  • CO2 emissions reduced by 10-20%, depending on test cycles
  • cheaper (50-70%) than full hybrids, according to automotive equipment manufacturer Valeo
  • unlike existing 12 V and 24 V vehicles, they can accept charging from regenerative braking and other regeneration (thermoelectric, exhaust heat, suspension, etc.); and they can drive the wheels electrically and provide additional power 

Stationary applications matter too

Batteries are not just central to mobile and automotive applications, but increasingly also to stationary energy storage.

Electricity being consumed as it is produced there must be sufficient supply to meet variations in demand. At times of peak demand extra capacity must be available to respond rapidly.

If demand cannot be met, the stability and quality of the power supply suffer and may result in brownouts or worse. To balance demand and supply additional generation, a certain amount of storage may also be necessary. It currently mainly takes the form of pumped hydro, which makes up the bulk of electricity storage.

Advanced batteries are set to play a major role in the future global electrical energy storage landscape and in grid management, in particular as the share of renewable energies (REs) grows.

A new generation of advanced safe, low-cost and efficient enough batteries to allow for storage on the grid has paved the way to the first instances of large-scale energy storage for the electric distribution network. The next-generation advanced batteries include Li-ion, sodium metal halide, NaS (sodium sulphur), advanced lead-acid and flow batteries.

To prepare International Standards for rechargeable batteries used in RE storage, TC 21 and TC 82: Solar photovoltaic energy systems, set up a Joint Working Group, JWG 82: Secondary cells and batteries for renewable energy storage. 

Finding the right chemistry for the right use

IEC TC 21 lists the key areas of battery standardization as starting, lighting, ignition (SLI) also named “starter” batteries, which supply electric energy to motor vehicles; automobile hybrid/electric vehicle cells; traction batteries; and the stationary batteries of the VRLA type.

TC 21 has broadened its scope to include technology and chemistry for flow batteries, which are starting to be deployed in the market and, as such need international standardization regarding performance, performance tests and safety.

Flow batteries are rechargeable batteries in which electroactive chemical components dissolved in liquids (electrolytes) stored externally in tanks and pumped through a membrane convert chemical energy into electricity.

To develop standards for flow batteries that cover safety, performances, installation, terminology and other necessary requirements, TC 21 set up JWG 17: Flow battery systems for stationary applications, with IEC TC 105: Fuel cell technologies, as flow batteries and fuel cells share certain characteristics.

TC 21 was created in 1931 and currently brings together 25 Participating countries and 17 Member countries.  Around 215 experts are active in its standardization work.

In view of the fast expanding energy storage needs from mobile, e-mobility and stationary applications, IEC TC 21 and IEC SC 21A are unlikely to see any reduction in their workload in the foreseeable future. 

VAleo electric turbo for 48V Electric superchargers used in 48 V mild hybrid vehicles cut emissions and fuel consumption (Photo: Valeo)
Varta 12V car battery Varta 12 V 80 Ah automotive battery (Photo Varta)