By Dr Inderpreet Kaur, IEEE Senior Member
Though the concept of electric vehicles (EV) has been around for a long time, it has drawn a considerable amount of interest in the past decade – especially amid a rising carbon footprint and other environmental impacts of fuel-based vehicles. Battery Management Systems (BMS) still face many challenges like fires or explosions, which at times can overshadow the advantages of EVs, however EVs are still more efficient than an internal combustion engine as they have fewer moving parts that need maintenance. It also has much less operative noise, as there are not clutch, gears, exhaust pipes, or spark plugs on the vehicle. As the name suggests, EVs include two categories: All Electric Vehicles (AEVs) and Plug-in Hybrid Electric Vehicles (PHEVs). While AEVs have one or more electric motors, their batteries get charged by plugging into the grid. Whereas, PHEVs have an electric grid to charge and fuel to power the internal combustion engine.
Electric Vehicle Technology
Due to both the presence of electric motors and the absence of spark plugs, gears, etc., EVs can tremendously increase the energy efficiency of the transportation industry. EVs are much more efficient at converting chemical energy into electrical energy to drive a motor than conventional internal combustion engines are at powering vehicles. Furthermore, the usage of electric vehicles is more eco-friendly due to the absence of pollution from vehicles and reduced dependency on oil that is required to ignite combustion engines.
BMS are the heart of any EV and currently, either nickel metal hydride or lithium-ion technology is used for the batteries. Lithium-ion batteries offer many advantages over nickel metal hydride but the recharging time of EVs is a challenge as it limits their use to shorter trips.
Role of Nano Technology in EV Industry
The main challenge faced by EVs are their batteries. They are very costly and have a short charging life. The battery performance of an EV could be enhanced by adopting Nanotechnology. This technology can address the gaps in e-mobility and have great benefits. On top of this, specific attributes of lithium batteries could be improved by using nanoparticles and nanocomposite materials. Battery performance parameters such as weight reduction, energy efficiency, life cycle, improved control, and communications could be increased by using Polymer nanocomposites, nano-enhanced sensors, and nanostructured metals.
Nanotechnology in Batteries
Specific performance parameters of batteries can be achieved through Nanotechnology. Conventionally, for lithium-ion batteries, negative electrode graphite powder has been used as an intercalation material. If micrometer-sized powder were replaced with carbon nanomaterials (e.g., carbon nanotubes), then the rate of insertion or removal of lithium and the battery capacity can be improved. The current density of electrodes will be increased because the diffusion path for the lithium ions is reduced, their mobility is enhanced, and electrical conductivity is increased. This makes the electrochemical reaction occur more efficiently and ultimately the use of nanomaterials will increase the efficiency of the battery.
The carbon nanotubes can bind to much higher concentrations of lithium because they have a high surface area. Another alternative for negative electrode materials will be Nanowires made of titanium dioxide (TiO2), vanadium oxide (V2O5) or tin oxide (SnO). Though the commercial manufacturing of these materials is still in its early stages, to date, most of the commercially available oxide materials are Li (NiCoAl)O2, Li (NiMnCo)O2, LiMn2O4, Li (AlMn)2O4, or LiCo2O4. But all these materials are neither cost-effective nor safe. The nanostructuring of these materials has been shown to significantly improve their intercalation capacity. Research is still being done to find optimum compositions to attain better performance of batteries that will be economical, light, and compact.
Therefore, the objectives of future EV research will be focused on improved charging periods of batteries, nanomaterials to improve the efficiency of batteries by bringing down the cost of nanomaterials for batteries as well as the size and weight of battery pack, and commercial development of these nanomaterials. This also will automatically improve the battery management and thermal management systems of the battery pack of an EV.