Integrated Cooling System for Electric Motorsports

Summary

UniBo Motorsport partnered with ToffeeX and BI-REX to create an innovative integrated cooling solution for their MotoStudent electric racing motorcycle. This groundbreaking project showcases the powerful combination of physics-driven generative design with selective laser melting additive manufacturing to solve one of motorsport’s most demanding thermal challenges.

The centerpiece of this innovation is a topology-optimized integrated tank/cooler that cools both the motor control inverter and the liquid cooling circuit using dry ice sublimation as the primary cooling medium. Rather than relying on traditional separate components or conventional manufacturing approaches, this design was conceived, optimized, and manufactured as a single integrated part—something possible only through the combination of advanced design software and additive manufacturing technology.

The project demonstrates that in high-performance motorsports, where margins are measured in hundredths of a second and thermal limits are performance ceilings, the intersection of computational design excellence and manufacturing innovation can unlock entirely new possibilities.

From initial requirements to a race-ready component took approximately two months, validating the speed and effectiveness of this integrated design-to-manufacturing workflow.

Introduction

In electric motorcycles, thermal management is not merely a reliability concern; it directly determines achievable power output, determines lap times, and drives race strategy.

The primary thermal challenges in electric racing arise from three sources: the power electronics (inverters and motor controllers) that switch megawatts of current at high frequencies; the traction motor generating significant waste heat; and the battery pack that must maintain optimal operating temperatures. Each thermal source has different temperature sensitivities and cooling requirements, traditionally requiring separate cooling circuits and components.

UniBo Motorsport’s MotoStudent motorcycle faced a particularly acute version of this challenge: the compact design envelope of a racing motorcycle severely limits space for cooling infrastructure. Every component must earn its weight and volume. The team needed to cool the inverter and motor simultaneously while minimizing system weight and volume, contradictory objectives that demanded innovative solutions.

This is where physics-driven generative design and advanced additive manufacturing converged. Rather than adapting conventional cooling architectures to electric racing constraints, the team asked a fundamental question: what does an optimal thermal management system look like when you remove conventional manufacturing limitations?

The answer came from the integration of ToffeeX’s topology optimization with SLM additive manufacturing, resulting in an integrated cooling component that would be impossible to manufacture using conventional methods.

The Application: Electric Motorcycle Thermal Management

Modern electric racing motorcycles generate substantial thermal loads despite their inherent efficiency advantages over combustion engines. The power electronics alone, specifically the inverter converting battery DC power to three-phase AC power for the motor, can dissipate tens of kilowatts during a race. This heat must be managed to maintain inverter junction temperatures within safe operating windows (typically below 80-100°C depending on semiconductor technology).

Simultaneously, the liquid cooling circuit that manages motor winding temperatures must remain within operational limits to sustain continuous power output. In racing conditions lasting 15-45 minutes, depending on track and event format, any thermal throttling or component de-rating directly reduces available power and ultimately race performance.

UniBo Motorsport’s approach was to integrate both cooling functions into a single system: a compact tank that serves simultaneously as an inverter cold plate and a motor coolant tank. The innovation came through the internal geometry. Rather than using traditional fin structures or simple rectangular passages, ToffeeX generated a topology-optimized cooling structure tailored specifically to each function.

Crucially, the system was designed to operate with dry ice sublimation as the primary cooling medium. For a race weekend, the team can pre-cool the tank with dry ice before the race, allowing the sublimation energy to provide continuous cooling throughout the race duration.

Design Process: Physics-Driven Topology Optimization

ToffeeX’s role in this project centered on solving a complex multi-objective optimization problem: optimizing heat transfer and pressure losses for the inverter and the ice tank, combining them into a single, manufacturable component.

Problem Definition

The design process involved two separate optimizations: one for the cold plate, using algorithms suited for forced convection, and another for the ice tank, employing optimization methods for natural convection and conduction with the dry ice pellet.

We identified two main design domains:

1. Cold Plate Design Domain: This area, in direct contact with the inverter, was optimized to maximize heat transfer from the electronics to the cooling fluid, leveraging forced convection principles.
2. Dry Tank Design Domain: Here, the objective was to maximize the internal surface area available for contact with the dry ice pellet, while minimizing weight in accordance with predefined limits, accounting for heat transfer via natural convection and conduction.

Optimization Approach

Although the optimization workflows for the cold plate and ice tank were decoupled, we carefully set boundary conditions in each case to account for the presence and thermal influence of the other component.

For instance, when optimizing the cold plate, a heat transfer coefficient was specified at the tank boundary to simulate the actual interface with the dry ice chamber.

This approach ensured that, while each subdomain was optimized independently, the thermal interactions were adequately reflected through realistic, physically meaningful constraints and parameters.

Using ToffeeX’s physics-driven generative design platform, we manage to:

• Maximize thermal energy transfer from the inverter heat source to the cooling system, accounting for phase-change behavior as dry ice sublimes
• Optimize motor coolant flow distribution to ensure uniform cooling across the entire motor cooling jacket circuit
• Minimize pressure losses in both circuits to reduce parasitic power requirements
• Respect manufacturing constraints inherent to SLM technology, including minimum wall thickness (typically 1-1.5 mm) and overhang angle limitations

The team explored multiple variants by adjusting the relative weighting between heat transfer maximization and pressure loss minimization, enabling them to understand the full design landscape.

This iterative approach took weeks rather than months compared to traditional CFD-driven manual design refinement, dramatically accelerating the development cycle while ensuring the selected design represented an informed choice rather than an intuitive guess.

Design Selection

From the multiple optimized designs generated, the team selected a final geometry balancing three critical factors for motorsports applications:

• Thermal performance sufficient to maintain inverter and motor temperatures within safe operating windows throughout a race
• Pressure losses within the motorcycle’s thermal management power budget
• Manufacturability via SLM, including structural integrity and the ability to withstand race-day conditions

The Manufacturing Process: Selective Laser Melting

BI-REX Competence Center employed selective laser melting (SLM) to manufacture the optimized cooling component. SLM is a powder-bed fusion additive manufacturing process uniquely suited for this application.

The process enables geometric complexity impossible with conventional manufacturing: complex internal channels, optimized surface features, and integrated structures that would require expensive multi-step assemblies if manufactured conventionally.

Advantages of SLM for This Application

Geometric Freedom: SLM enables topology-optimized cooling channel geometries that would be impossible to machine, cast, or stamp. Internal channels can follow the physics-optimal flow paths rather than simple rectangular designs.

Integrated Design: Multiple components are fabricated as a single integrated part, eliminating assembly operations and potential leak points.

Reduced Weight: The optimized internal geometry and lack of unnecessary material mean the final component weighs substantially less than conventional designs—a critical advantage in racing where every gram affects performance and handling.

Design Performance

ToffeeX optimization generated multiple design variants with estimated performance characteristics. The final design selected balanced:

Note: Specific quantitative results are pending completion of experimental testing and will be added to this section upon availability.

Experimental Validation

Validation testing of the integrated cooling component is underway, including:

• Thermal performance testing under simulated race thermal loads, measuring inverter and coolant temperature responses
• Pressure drop characterization of both the inverter cooling circuit and motor coolant flow path
• Real-world track validation as the component operates in the UniBo Motorsport motorcycle during the MotoStudent competition

Results from these validation tests will be documented and added to this case study upon completion.

Conclusion

The collaboration between UniBo Motorsport, ToffeeX, and BI-REX Competence Center demonstrates a new paradigm for thermal management in advanced engineering applications. By combining physics-driven topology optimization with selective laser melting additive manufacturing, the team created an integrated cooling system that would be impossible to develop using conventional design and manufacturing approaches.

The integrated inverter/water cooling component represents more than an incremental improvement over traditional designs—it exemplifies a fundamental shift in how thermal engineering can approach complex multi-objective challenges. When optimization algorithms and additive manufacturing work in concert, the result is components that are simultaneously lighter, more compact, higher-performing, and achievable in accelerated timelines.

For UniBo Motorsport, this innovation provides a critical competitive advantage in MotoStudent racing. For the broader engineering community, the project illustrates a clear path forward: advanced thermal challenges aren’t solved by incrementally optimizing existing designs, but by removing manufacturing constraints that force compromise in the first place.

As electric motorsports continues to evolve and performance margins narrow, the teams that embrace physics-driven design and advanced manufacturing will define the performance frontier.

About UniBo Motorsport

UniBo Motorsport is the official motorsports team of the University of Bologna, Italy. Competing in the prestigious MotoStudent international championship, the team designs, builds, and races lightweight electric motorcycles. The competition emphasizes integrated systems design, where aerodynamics, thermal management, battery optimization, and control systems must work in concert to achieve competitive performance.

The MotoStudent competition attracts universities from across Europe and beyond, fostering innovation in electric propulsion, advanced manufacturing, and integrated engineering design. UniBo Motorsport’s participation has established the team as a leader in innovative thermal management and systems integration for electric racing.

About BI-REX Competence Center

BI-REX is a specialized competence center focused on advanced manufacturing, design optimization, and materials engineering. The center provides expertise in selective laser melting, design for additive manufacturing, and process optimization, translating computational designs into manufacturable, high-performance components.