Fabrication of pouch cell supercapacitors using abundant coal feedstock and their hybridization with Li-ion battery for e-rickshaw application

The environmental concerns and market demands created high demands of electric vehicles (EVs), but still the energy storage systems are lagging behind the fuel-based vehicles. Even though recent development in battery technologies bring forth great opportunities for EVs, the necessity and a good supply chain of electrode materials, does not fulfill the requirement of EVs. In India, battery-operated e-rickshaws face challenges like insufficient charging facility, low driving range, high battery cost, battery replacement, and disposal. To address the power delivery issues, we have designed and developed an indigenous Hybrid Battery Management System (HBMS) using fabricated coal-based supercapacitors and commercial Li-ion batteries for application in an e-rickshaw. For this study, we have fabricated 500 F pouch cell supercapacitors using high quality activated carbon derived from low-grade coal feedstock which shows excellent properties comparable to the commercially available supercapacitors. Five coal-based pouch cell supercapacitors (500 F) were connected through series parallel combination with commercial supercapacitor (Greencap. 500 F) to make a complete supercapacitor pack of 25 F and 54 V suitable for testing in the e-rickshaw (48 V and 1 kW motor). After implementing the developed hybridized battery management system (HBMS) in e-rickshaw, it showed the maximum speed of 45 km/h with additional power gain of 433 W. The analysis of data showed that the application of coal-based supercapacitors along with Li-ion battery had improved the overall performance of the e-rickshaw. Thus, this study has opened up a new venture of using abundant coal powder in fabricating low-cost pouch cell supercapacitor for using in EVs in a sustainable way that can influence the existing commercial battery market.