eUSRacing is a multidisciplinary team of students from the University of Seville, Spain. We design and manufacture an electric motorbike prototype for MotoStudent, a competition where universities from all over the world compete to build the best motorcycle for a MotoGP-style race at the MotorLand Arag´on Circuit. Engineering, marketing, and business students join forces with a single goal: creating the most efficient and high-performing electric motorbike in the world. We are all united by the same passion: eUSRacing.
MotoStudent
MotoStudent is an opportunity to develop both soft and hard skills for students like us, as we face the challenges of leading a competitive team while designing and manufacturing a racing motorbike. It is a biennial competition divided into two phases:
- MS1: In addition to designing, manufacturing, and testing the prototype, teams must submit a series of deliverables to the organization. These documents demonstrate our progress and prove that our prototype complies with current regulations. Furthermore, one of the deliverables involves presenting a technical innovation to foster creativity and technological advancement among the teams.
- MS2: All teams meet face-to-face at the circuit, where students have the opportunity to work as racing professionals. The prototype must pass a series of static, electrical, and dynamic tests to ensure it complies with regulations and is a safe vehicle for the rider. All this leads up to the main event: a 7-lap race around the FIM MotorLand Circuit Layout.
The Team
eUSRacing is made up of students from all backgrounds: engineering students in charge of designing and manufacturing the prototype, and marketing and business students who build the eUSRacing brand and ensure the project’s financial viability. The entire team is driven by a deep ambition and passion for this project, which serves as our primary fuel; however, none of this would be possible without the support of our sponsors. Developing an electric racing motorcycle is a high-cost endeavour, and we work tirelessly to bring our vision to life by securing the partnerships and resources necessary to compete at the highest level.
The Motorbike
In the last edition, we achieved a very ambitious electric prototype design, featuring a high-capacity battery, sophisticated controller programming, and an efficient control system with advanced features. However, manufacturing delays and some setbacks regarding the controller’s reliability, along with certain design flaws, prevented us from reaching our goals.
This edition, armed with the knowledge acquired from past experiences, we are designing an efficient, reliable, and competitive prototype. Our aim is not only to fulfil our previous objectives but to surpass them.
The Battery Pack
Getting down to technical details, the battery pack for the last edition was designed and manufactured in-house. It consisted of 560 cells (model INR21700-50S) in a 28s20p configuration (series and parallel), achieving a 10 kWh capacity with a nominal voltage of 103.6V . The battery sizing was performed using Matlab and Simulink, optimizing the pack for the specific circuit, expected race conditions, and maximum motor
power.
The battery pack was divided into three modules, with a configuration of 9s20p each, except for one larger module which was 10s20p.
All cells in the pack were connected using 0.8mm nickel sheets, except for the main positive and negative terminals, which utilized 1.5mm sheets.
The modules were connected via flexible copper braiding, which allowed us to fold the modules into place. All module faces were insulated with a 0.5mm material featuring a resistivity of 1012 Ω · cm.
The manufacturing of this pack was a labour-intensive and time-consuming process, which ultimately led to significant manufacturing delays.
In addition to the electrical specifications, the design process prioritizes the thermal characteristics of the battery pack. A comprehensive series of thermal simulations was conducted to identify potential hotspots within the assembly and determine the theoretical peak temperatures under race conditions.
By proactively identifying these critical areas, we optimized the placement of eight BMS-monitored thermistors, ensuring real-time tracking of the pack’s thermal state. These simulation models were subsequently validated through prototype testing prior to the race. The empirical data showed a high degree of correlation with our initial models, confirming the thermal stability and overall safety of the battery system.
Electrical insulation monitoring is integrated into the system through the Battery Management System (Orion BMS 2) and the Insulating Monitoring Device (Bender ISOMETER® IR155-3204). The BMS provides comprehensive control over thermal management and cell balancing during both charging and discharging cycles. The IMD—mandated by competition regulations—is configured to continuously monitor the insulation resistance between the high-voltage system and the chassis or other conductive structural components.
Both devices serve as primary controllers within the High Voltage Disconnect (HVD) circuit. They are designed to manage the presence of high voltage outside the battery enclosure by instantly triggering a disconnect in the event of an insulation fault, thermal anomaly, or cell imbalance. This fail-safe approach ensures the safety of the driver and team members while maximizing the battery pack’s lifecycle. Furthermore, both units communicate with the Electronic Control Unit (ECU) via CAN bus. This integration enables a proactive error-detection system, ensuring the prototype operates within safe margins and prevents the system from reaching critical thresholds.
Finally, the battery pack is recharged using a custom-engineered charger, fully designed and manufactured in-house to meet our specific system requirements. It is capable of a State of Charge (SoC) transition from 20% to 80% in under 40minutes, making us one of the few teams in the competition to successfully implement a proprietary charging solution.
The hardware is designed for versatility, supporting both single-phase and three-phase AC inputs, ensuring full operational capability regardless of the charging environment. To guarantee safety, the charger maintains continuous CAN bus communication with the BMS. This closed-loop system monitors thermal and electrical parameters in real-time, adjusting the charging profile to ensure the integrity of the cells and the safety of the overall system.
Driving Future Innovation through Technical Collaboration
Looking ahead, our team is committed to further optimizing the prototype’s performance, with a specific focus on advancing the battery pack’s architectural design. To achieve this, we are proud to announce our collaboration with BatteryDesign.net. Their comprehensive technical resources and specialized documentation have been instrumental in our current design cycle, providing our engineers with the high-level insights necessary to push the boundaries of energy density and thermal efficiency. This partnership represents a significant step forward for our project; leveraging the expertise found at BatteryDesign.net ensures that our upcoming iteration meets the highest standards of the electric racing industry. We are incredibly grateful for their support and look forward to showcasing the results of this synergy on the track.
Stay tuned for more updates on our technical journey and the official unveiling of our next-generation battery pack. For a deeper look into our design process and to see our prototype in action, follow us on our social media channels:
- Instagram: @eUSRacing
- LinkedIn: https://www.linkedin.com/company/eusracing/
Hi, at the moment are available also some good 4695 cells with 282 Wh-kg as Eve G11;
specifications are 3,7v x 32Ah x 420gr x 5-6C discharge (10C peak)
it seams there is also another versions (Eve G13) with 10C rate discharge but with less energy density; so may-be the G11 5C discharge version is already enough and a better fit
it will be interesting to compare if doing the battery pack some with high end 4695 cells could improve respect the the classic INR21700-50S.. I imagine that 21700 having more surface can dissipate better the heat, but new 4695 could be improved in lower inner resistence and good energy density and a lot less work to do a battery pack?