Electric mobility is witnessing a strong revival compared to the last EV wave in India. Present-day articles wax eloquently about EVs' newfound efficiencies and sustainability advantages compared to IC engine vehicles. But EVs have been around for more than a century.
Just like then, the heart of every electric vehicle continues to be its battery even today. Nearly 40% of the total cost of the modern EV is contributed by its battery, and these clusters of cells play a crucial role in determining the vehicle's range, performance, and practicality.
In India, the EV wave began in 2009. These EVs were primarily fitted with lead-acid batteries because of their relatively lower costs, ease of availability at the time, and familiarity within the ecosystem. However, these lead acid batteries had a lower energy density and were generic in their form factor and primitive in their design. But this was India's first wave of electric mobility. Although lacking in design and performance, it was practical and paved the way for electric vehicles in the country.
Today, however, the Indian EV segment has evolved drastically to a point where it can be compared to global electric mobility markets. The modern EV customer in India considers a practical range as a given, while performance, short charging times, top-of-the-shelf technology, and design are must-haves. It is these kinds of market requirements that have necessitated the transition from lead-acid batteries to Lithium Ion (Li-Ion), Lithium Iron Phosphate (LFP) and Lithium Polymer (Li-Poly) ones instead.
India is the second largest two-wheeler (2W) market in the world. It is no surprise that 6,69,845 units of the total 10,54,938 electric vehicles sold in the country in 2022 were 2Ws. The penetration of e-2W was 4.1% of all 2Ws (>15 million units) sold in the country in 2022, against 1.1% in 2021. From a battery standpoint, motorcycles are a unique challenge compared to four-wheelers (4W) because of their form factor and diminutive dimensions, which drastically limit the packaging size of the battery. Sprightly performance is another characteristic that is expected from motorcycles. Most bikes are also ridden in hot, dusty conditions on bad roads, making their batteries need to be adequately insulated from thermal and mechanical shocks to operate safely.
All these aspects mean that the batteries for electric bikes must be small yet have a high energy density and sufficient thermal stability. Today, NMC or NCA-based Li-Ion cells appear better suited for motorcycles and may be replaced by other chemistries with higher energy and power densities in the future.
With all this talk about batteries, it makes sense to become familiar with their construction and functioning to understand why some types are better than others for specific applications. All batteries, regardless of their type, consist of a bunch of cells that are connected either in series, parallel or a combination of both depending on the intended application. Each cell comprises an anode, a cathode, separators, and an electrolyte. The separators insulate the anode and cathode from each other, while the electrolyte facilitates the flow of ions from the cathode to the anode through the external circuit. Thus, it is the cathode and the anode of the battery that allows us to store and expend electricity. At the same time, the separators and electrolytes enable us to do this safely and in a controlled manner.
In lithium-ion batteries, cathodes are generally made from lithium oxide because of its reactive nature. The cost of these cells can be reduced by increasing the nickel and decreasing the cobalt contents, respectively, but this would also make them relatively unstable. Therefore, manganese and cobalt are added to increase the safety aspect of the cell but consequently add significantly to the price of the battery. Therefore, these chemistries must be researched and fine-tuned according to the intended application, operating conditions, required performance, and economics of the segment within which they will function.
Ample research is underway to find suitable substitutes for expensive materials like cobalt, which will reduce prices yet maintain the required high levels of performance and safety. Companies are also looking to replace liquid electrolytes in these batteries with solid ones (solid-state batteries) to improve energy density safely.
Unfortunately, India is forced to import most of these raw materials – lithium, cobalt, nickel, and manganese – from countries like Australia, China, and South Africa because of their expansive reserves. This absolute dependence on imports poses a challenge to the growth of the Indian EV sector. This is why we should explore the possibilities of alternate cell-chemistries like sodium ion (Na-Ion), which the Indian market could adopt because of the ample availability of these compounds within the country. These alternate chemistries are still under development and are a long way from reaching economic feasibility for mass production.
Today, although it is very premature to decide which cell chemistry will emerge as the best choice for the future, we can safely say that future batteries will have a much higher energy density, be safer to use, and be longer lasting.
Yes, that means electric motorcycles will move faster, go further, and put wider smiles on the faces of their riders in the years to come!
Dr Prajwal Sabnis is the Co-founder of Orxa Energies. Views expressed are personal. Photo courtesy: Grinntech.