A robust battery safety testing and certification programme for electric vehicle batteries will address customer anxiety and help India meet its e-mobility goals.
India has set ambitious goals for e-mobility. According to Union Minister for Surface Transport, Nitin Gadkari, the government is looking at electric vehicle (EV) sales accounting for 30% of private cars, 70% of commercial vehicles, and 80% of two, and three-wheelers by 2030. This is all a part of India’s commitment to have net-zero carbon emissions by 2070, made at the COP26 summit last year.
The government has already announced several policy initiatives to enable this, including Faster Adoption and Manufacturing of (Hybrid &) Electric Vehicles in India (FAME India). The second phase of the scheme, called FAME II, commenced in 2019 and has an allocation of Rs. 10,000 crore to provide incentives to the e-mobility industry.
Last December, the government also mandated the Automotive Industry Standards 156, prescribing safety standards for electric power trains of motor vehicles.
NITI Aayog, the central government’s think-tank, has also produced a draft of a battery swapping policy which is now open for discussions and suggestions from all stakeholders. Among its various proposals, the crucial ones are:
• An EV eco-system without in-built batteries. This would reduce upfront costs to customers and help develop a subscription-based Battery-as-a-Service (BaaS) model.
• Use of only Advanced Chemistry Cell (ACC) batteries or those with performance equal to or higher than the norms specified in FAME India;
• Compatibility of different battery components to ensure interoperability;
• Mandatory use of a state-of-the-art Battery Management System (BMS);
• Data sharing with different stakeholders on life, performance and history of usage of the batteries based on a Unique Identification Number (UIN).
All these are excellent initiatives that should go a long way towards incentivizing the popularity of e-mobility. There is, however, one development that the government needs to tackle urgently.
In the last few months, there have been multiple reports of e-two-wheelers catching fire, resulting in casualties. The reports, which went viral on social media, have the potential to dent prospective customers’ confidence in the safety of electric vehicles.
Alarmed by these reports, the government has ordered forensic investigations into each incident by the Defence Research and Development Organisation’s Centre for Fire, Explosive and Environment Safety. While the government has moved expeditiously, what is necessary is to move beyond these immediate incidents and think of ways to restore buyer confidence. The key is to develop an institutional mechanism to test EV batteries for their quality and certify them as safe.
Fires in EV batteries are primarily caused by internal short circuits. These, in turn, are caused by poor cell quality, unsafe battery design and faulty BMS.
Let us briefly understand each of these to appreciate better the role of industry standards for testing and certification.
Poor Cell Quality
An EV battery cell has an anode (positively charged), cathode (negatively charged) and a separator electrolyte packed together. Accidental contact internally can lead to a short circuit. Over the years, manufacturers have been attempting to produce batteries that have high energy density while maintaining operating temperatures during peak load in check. This would require manufacturers to strike the balance between delivering intended performance figures and choosing from an array of available materials. At the end of the day, the choice made by manufacturers when selecting cell chemistry and format should be aligned with the intended usage condition and manufacturing process involved.
Unsafe Battery Design
An EV battery is an array of cells packed together. The number of cells in such arrays and how they are packed depends on the expected output, which, in turn, depends on vehicle type, geometry and the promised performance. The packaging that holds these arrays together also plays a critical role in the safety of the battery. Pack these cells too closely or without adequate insulation, and it may cause problems A single loose bolt (caused by uneven Indian roads) inside an array of cells packed closely may lead to a fire.
A state-of-the-art BMS is a critical component in ensuring the safety of EV batteries. The charging of an EV battery involves the conversion of chemical energy into electrical energy and moving electrons from the external power source into the anode. Different cell chemistries have various threshold limits for charging. But each one has something in common – Lithium Dendrite formation – in case of overcharging. Lithium Dendrite is lithium ions that cluster around the anode, eventually forming an ice crystal-like formation. If enough of them get formed, they could eventually reduce the gap between the anode and the cathode, leading to short circuits and fires.
A smart BMS that senses the level of charge in each cell can avoid this by shutting off charging once an optimum charge has been achieved.
Role of Testing and Certification
A robust testing and certification programme can ensure that each aspect of an EV battery is tested – from cell quality, battery design and the BMS. It will involve multiple tests in electrical, chemical, corrosive, mechanical and abusive domains and simulating extreme weather, road and charging conditions to ensure that EV batteries withstand these.
Besides ensuring the safety of EVs, especially e-two and three-wheeler batteries, the mandating and popularising of such a testing and certification programme will go a long way to address the safety concerns of customers and meet the government’s goal of reducing carbon emissions in the transport sector.