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ELECTRIC VEHICLES Battery technologies recharging the Indian EV ecosystem

Jul 27, 2021

Mehul Shah, VP – Transport BU, Exide Leclanche Energy, Nexcharge - While India’s EV demand is witnessing a steady growth and the future seems bright, India’s battery demand is also expected to grow 51% by 2027. Understanding which battery offers what and the impact of choice on one’s vehicle is important. This article by Nexcharge – a joint venture in India between Exide, India and Lelanchè providing customised energy solutions – explains the different types of batteries, their pros and cons and hints on what could be the battery powering future EVs.

Three lakh, eighty thousand electric vehicles (EVs) were sold in India during 2019-20. Most of these sales occurred in the electric two-wheeler and low-speed electric three-wheeler market. Hence, companies are now cautiously optimistic about the EV market share growth in the years to come.

In a 2019 Niti Aayog report titled ‘India’s Electric Mobility Transformation Progress to Date & Future Opportunities’, it has been envisaged that if the FAME-2 scheme and other measures taken by both central as well as state governments are successful, then India could witness an EV sales penetration of 80% in two-wheelers & three-wheelers, 30% in private cars, 70% in commercial cars and 40% in buses by 2030. The EV market in this scenario is expected to grow at a CAGR of 69% between 2020-2027, whereas the battery demand for EVs’ is expected to grow at a CAGR of 51% by 2027. The most important part of any EV is its battery and its ability to store electricity used by the motor to power the vehicle’s wheels. The traction battery pack is the part of the vehicle that must be plugged in and recharged, and its efficiency helps determine the overall range of any vehicle.

Lithium-ion battery

Lithium-ion batteries have a high power-to-weight ratio, high energy efficiency and good high-temperature performance. In practice, this means that the batteries hold a lot of energy for their weight, which is vital for electric vehicles; less weight means the vehicle can travel further on a single charge. Lithium-ion batteries also have a low self-discharge rate, which means that they are better than other batteries at maintaining the ability to hold a full charge over time.

Nickel-metal hybrid battery

Nickel-metal hydride batteries are more widely used in hybrid-electric vehicles but are also used successfully in some all-EVs. Hybrid-electric vehicles do not derive power from an external plug-in source, instead, they rely on fuel to recharge the battery, which excludes them from the definition of an electric car. Nickel-metal hybrid batteries have a longer lifecycle than lithium-ion or lead-acid batteries. They are also safe and tolerant to abuse. The biggest issues with nickel-metal hydride batteries are their high cost, high self-discharge rate and the fact that they generate significant heat at high temperatures. These issues make the batteries less effective for rechargeable EVs, and this is why they are primarily used in hybrid EVs.

Lead-acid batteries

Lead-acid batteries are only currently being used in EVs to supplement other battery loads. These batteries are high-powered, inexpensive, safe and reliable, but their short shelf life and poor cold-temperature performance make it difficult to use them in EVs. There are high-power lead-acid batteries in development, but the batteries now are only used in commercial vehicles as secondary storage.

Ultracapacitors

Ultracapacitors are not batteries in the traditional sense. Instead, they store polarised liquid between an electrode and an electrolyte. As the liquid’s surface area increases, the capacity for energy storage also increases. Ultracapacitors, like lead-acid batteries, are primarily useful as secondary storage devices in EVs because they help electrochemical batteries level their load. In addition, they can provide EVs with extra power during acceleration and regenerative braking.

Market scenario

As far as the battery technology split is concerned, lead acid-based e-2Ws will dominate the market with a 54% share followed by 46% from lithium-ion. As per OEMs, sales of lead acid-based models dominated the market till October. Post-October, lithium-ion technology dominated the market as a few OEMs also received the FAME-II certification. Overall, the OEMs believe that lead-acid technology will disappear from the market in the next five years as the industry is fast transitioning from lead-acid technology to lithium-ion. As per CES analysis, the share of lead-acid technology will reduce to 3% in 2025 from 54% in 2019.

In the three-wheeler segment for battery demand, 99% of demand came from lead acid-based e-rickshaws last year because of the aftersales market, which is entirely dependent on lead-acid technology. Slowly, the OEMs are shifting towards lithium-ion technology. Last year, 12% of sales came from lithium-ion technology and going forward, as per OEMs, the share of lithium-ion batteries can increase up to 40% by 2024 & up to 90% by 2030.

Hence in all views, lithium-ion batteries will be most preferred in EVs in the future and suitable for all types of applications. Although all lithium-ion batteries have many aspects in common, there are a variety of different types of lithium-ion batteries that are available in the market. Each lithium-ion battery type has its characteristics, and this means that different types of lithium-ion batteries will be used in different areas.

Accordingly, it is necessary to choose the right type of lithium-ion battery for any application - understanding the different types and their characteristics enables the right type to be chosen for any particular application. There are few types of lithium-ion batteries; in EVs, the most preferred ones are Lithium Iron Phosphate battery (LFP), Lithium Nickel Manganese Cobalt Oxide (NMC) and Lithium Manganese Oxide, Lithium Titanate (LTO) & Metal Air.

Lithium Iron Phosphate (LFP): These batteries are more tolerant at full-charge conditions and are less prone to stress compared to other lithium-ion batteries when subjected to prolonged high voltages. As a result, these types benefit from low-resistant properties, thereby increasing their safety and thermal abilities, making them ideal for electric motorcycles and vehicles. The only drawback is they have low-voltage capacities and offer less energy than other types of lithium-ion batteries.

Lithium Nickel Manganese Cobalt Oxide (NMC): They provide high-specific energy options, reasonably good specific power and have a decent lifespan.

Lithium Manganese Oxide (LMO): They offer fast charging and high-current discharging with increased thermal stability and provides enhanced safety, making it ideal for medical devices, electric vehicles and power tools.

Lithium Titanate (LTO): They are one of the faster-charging batteries in the lithium-ion category, but they do have their disadvantages. However, they are worthy because they have lower inherent voltage and lower specific-energy ratings over conventional lithium technologies.

Metal Air: Li–air cells are of interest for EVs because of their high theoretical specific and volumetric energy density. Electric motors provide high efficiency (95%). Li–air cells could offer a range equivalent to today’s vehicles with a battery pack one-third the size of standard fuel tanks, assuming the balance of plant required to maintain the battery was of negligible mass or volume.

Hydrogen fuel cell technology: Fuel cell electric vehicles (FCEVs) are powered by hydrogen. They are more efficient than conventional internal combustion engine vehicles and produce no tailpipe emissions — they only emit water vapour and warm air. FCEVs are fuelled with pure hydrogen gas stored in a tank on the vehicle. Like conventional internal combustion engine vehicles, they can fuel in less than four minutes and have a driving range of over 300 miles. FCEVs are equipped with other advanced technologies to increase efficiency, such as regenerative braking systems, which capture the energy lost during braking and store it in a battery.

Pushing energy for double output

The lithium-ion battery industry is continually evolving with myriad types that can be matched for any number of applications. The technology is continuously being improved upon. Researchers from the University of Warwick have developed a new technology that allows conventional lithium-ion batteries to charge five times faster, while Solid Energy Systems has developed a more powerful battery using a lithium-metal foil and a proprietary electrolyte that is purported to have double the energy density of standard Li-ion platforms.

To conclude, increased energy capacities, faster recharge time and enhanced safety are just the tip of the iceberg for new types of lithium-ion batteries. We can expect further developments as the latest technology is applied to their development. It will be interesting to see where this time-tested and tried storage medium is headed in the near future.

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  • Mehul Shah

    VP – Transport BU

    Exide Leclanche Energy

    Nexcharge

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