The importance of battery safety in electric vehicles
Despite fears of a slowdown, the global market for electric vehicles (EV) is predicted to keep on growing. The safety and performance of EV batteries are essential to their growth and their ability to contribute to climate targets.
There are few industries in the clean energy sector as dynamic as that of electric vehicles. According to Euromonitor International, 25% of all new passenger car registrations are forecast to be electric in 2024, exceeding 17 million units in sales globally. This is up from the International Energy Agency's (IEA) estimates of 14 million sold in 2023, and more than 10 million in 2022.
What's more, the total fleet of EVs (excluding two/three-wheelers) is expected to grow from almost 30 million in 2022 to around 240 million in 2030.
This is good news for the planet as an increase in the use of EVs will help to reduce emissions from road transport, a sector that, according to the IEA, accounts for more than 15% of energy-related emissions worldwide.
Battery power
In order for there to be greater uptake of EVs, their safety, performance and affordability need to be assured, for which batteries play a fundamental role.
The IEC publishes a wide range of international standards to support EV technologies to ensure they operate and connect safely to the electricity grid. Combined with the IEC Conformity Assessment Systems, they contribute towards ensuring interoperability and the safe functioning of all components, including the batteries.
The vast majority of EVs are powered by lithium-ion batteries, which have evolved to store ever greater amounts of energy for a smaller price. Yet there are a number of well-known disadvantages, namely that their performance degrades over time, and once they are no longer usable, recycling is complex. What's more, there are concerns around the environmental impact of the mining of the critical minerals needed to make new batteries, such as lithium, cobalt and nickel.
IEC TC 21 publishes international standards for lithium-ion cells including the IEC 62660 series on secondary lithium-ion cells for the propulsion of EVs. The three-part series covers performance testing, reliability tests and safety requirements.
Safety first
Pascal Mast, Director Sustainable Technologies at TÜV SÜD, an international testing, inspection, auditing and certification service provider said EV batteries undergo strict testing to ensure their safety and performance before being released on the market, with the battery management system (BMS) being a key focus.
"The BMS is like the battery's computer, checking all the necessary battery parameters of each cell, or cell modules, and specifying how the battery can be operated optimally. It also contains a wealth of data that can be reviewed and analyzed to check not only that the safety mechanisms are in place, but that the battery has not been tampered with and that it meets all the technical specifications", he stated.
Why charging matters
EVs use the power provided by the electricity network to recharge their batteries. Most of this demand is met by home charging, which is generally slow. However, there is an increasing demand for publicly accessible chargers, and in particular for fast chargers along highways and motorways. Greater access to these can address concerns around range or the distance an EV can travel, which continues to be a barrier to broader EV adoption.
According to the IEA, at the end of 2022, there were 2,7 million public charging points available worldwide, more than 900 000 of which were installed in 2022.
How a battery is charged matters, not only for convenience, but for the performance and durability of the battery itself, said Mast. "To optimize the life and safety of a battery, a mix of fast and slow charging is best," he added.
"Battery charging stops when the first cell is full, so the battery doesn't overheat. By charging as slowly as possible, it allows time for a balanced charge across all the cells, so that each cell is filled to capacity," he explained.
Giving batteries a second life
However, EV batteries don't last forever and most warranties give them a lifespan of around 8-10 years, making their environmental impact in terms of e-waste and recycling a real concern.
To address this, there is an increasing trend towards giving them a "second life" by using them in stationary storage, where the performance requirements are lower and there are fewer safety risks. According to some estimates the capacity for the re-use of batteries in storage systems will reach over 950 gigawatt hours by 2030.
IEC TC 120 was set up specifically to publish standards in the field of grid integrated electrical energy storage (EES) systems in order to support grid requirements. An EES system is an integrated system with components, which can be batteries that are already standardized. The TC is working on a new standard, IEC 62933-5‑4, which will specify safety test methods and procedures for lithium-ion battery-based systems for energy storage.
These "second-life" batteries can be used in a variety of contexts, from households to back-up energy sources in areas where the electricity supply is less reliable. An example of this is the first project of the IEC Global Impact Fund, Catalyzing innovation for circular models in Africa – turning battery e-waste into e-resources, which will support an SME-led project in Kenya to promote sustainable battery e-waste management.
As part of the project, Differ Community Power (DCP), an international provider of solar energy services to communities, will determine the feasibility of using second life lithium batteries to rehabilitate solar PV installations at critical locations such as schools, health centres and hospitals.
Conformity assessment is key
The safety and performance of batteries remains a top concern whatever their use. Conformity assessment, such as testing and certification, plays an important role.
IECEE (IEC System of Conformity Assessment Schemes for Electrotechnical Equipment and Components) offers a broad certification service portfolio that includes battery safety, battery performance, battery safety when installed in end products, energy efficiency, EMC and hazardous substances.
It also has a specific programme for EVs through its registered certification body testing laboratories (CBTLs) and national certification bodies (NCBs) which can test and certify charging systems and plugs against IEC Standards.