Can Team Solarium drive 1600 km on a single charge? A quick peek into the innovations by the student team

Team Solarium is a group of engineering students from Pimpri Chinchwad College of Engineering, Pune that designs and manufactures electric solar vehicles. Founded in 2016, the team has been participating and winning big in multiple national level competitions including National Solar Vehicle Challenge 2017 and Electric Solar Vehicle Championship (ESVC) in 2018, 2019, 2020.

Their current ambition is emerge victorious in India’s first solar vehicle cross country challenge. In March 2022, Imperial Society of Innovation Engineering (ISIE) along with ARAI Pune, is organizing ESVC 3000+ (Asia’s largest solar event). In this event, the teams will design and construct a solar car as per the technical specification and drive it for 1600 km from Delhi to Pune on a single battery charge (over 8 days) – powering the vehicle through solar energy only. Team Solarium has started in-depth research and preliminary design to prepare.

This article takes a look at the innovations the team has come up with in recent years to build their electric solar vehicles. 

Carbon fiber monocoque chassis

The team has been manufacturing a light-weight Carbon Fiber (CF) monocoque chassis since 2017.

The chassis, designed and manufactured in-house, weighs 16 kg. They used Al honeycomb as a core material, 12K with 2*2 Twill weave pattern Carbon Fiber. Manufacturing method was ‘pattern to mould’. The team has made a CF steering wheel and seat which weigh 125 g and 450 g respectively. They have achieved a Fiber to Resin ratio of 0.61 and are optimizing it further. Solarium also has a CF battery box which is 40% lighter than the Aluminium battery box they designed in the first year. The team is also planning to design and manufacture CF rims in coming years.

Self-designed and manufactured brake caliper

The team has designed and manufactured their own brake caliper, which only weighs 350 grams while the calipers available in the market weigh 1.5 kg. The team wanted to reduce the unsprung mass and improve the vehicle handling during cornering. The caliper has been designed using lightweight high strength space grade material.

Automatic gear shifting

Team Solarium implemented automated electronic gear shifting mechanism. This technology is similar to the one used in F1 cars. This helped them gain maximum efficiency and deliver appropriate power as per the requirement. It drastically reduced the overall acceleration time which helped them achieve better ranking during the final endurance event.

The current available options in the market for automatic gear shifting are costly and these solutions were not found to be suitable to the conditions of the competition. The team used a simple lead screw mechanism replacing the traditional clutch lever mechanism, thereby reducing its weight and complexity.

Semi flexible solar array

Solarium collaborated with solar panel manufacturer, Waaree, and designed its own semi-flexible solar panels. It gave the vehicle an added advantage by reducing the weight significantly since glass is absent. It also helped them maintain the vehicle’s aerodynamic shape. There was an increase in the efficiency since the reflection losses are decreased because of ETFE (Ethylene tetrafluoroethylene) as it has matte finish and helps in absorbing more sunlight. The flexibility made the panels easy to handle and install.

Specifications: Maximum voltage – 52.63V, Maximum current – 8.79A, Maximum power- 462.58 W, Efficiency – 21% 

For the upcoming season, the team plans to reduce the number of bypass diodes in order to reduce the heating, and reduce the layers of encapsulant to minimize refraction losses and decrease weight.

Autonomous driving

The team made a fully Autonomous Solar Electric Vehicle based on the event restrictions. The python programming language, equipped with the OpenCV library, enabled them to run the vehicle driverless. A Logitech webcam acted as an image sensor for Raspberry Pi 3B+ microprocessor.

The incoming video feed was analyzed and processed through a self-developed algorithm. Using the onboard GPIOs on the Raspberry Pi 3B+, digital signal was given to the BLDC motor control for forward and backward movement and motor driver to drive the steering motor. This would provide highly accurate measurements at each step, making it a highly reliable system.

 IoT and Cloud computing

A data telemetry system using IoT (Internet of Things) and cloud computing was implemented to remotely monitor and control important vehicle parameters. The team designed its own IoT architecture, made use of IBM cloud computing platform and machine learning algorithms. The data acquired from various sensors placed all over the Electric Solar Vehicle was fed to a cloud platform to analyse the vehicle’s performance in real-time and provide necessary visual feedback under dynamic conditions.

We would like to thank Prasanth Kumar (Haritha TechLogix) and Pranav Nagaveykar for reviewing the innovations, and wish the best to Team Solarium.

If you would like to explore sponsoring the team or get in touch for any other details, they can be reached at kushise865@gmail.com.