Schukat sponsors student racing team in Formula Student Electric

In the Formula Student Electric (FSE) design competition, student teams from colleges and universities do all of the planning, development and construction of a 100% electric single-seater racing car. An independent jury judges the cars against a range of criteria, including driving characteristics (acceleration, braking behaviour, and handling), price, and reliability. The vehicles are also put to the test in practical disciplines on test tracks around the world. Other factors such as aesthetics, comfort, and the use of easily available, standard components increase the market value of the vehicle. In addition, each team is required to submit a concept, a cost report and a business plan that includes an overall strategy and marketing ideas. The winner is not the team with the fastest car, but the one with the best total package: construction, performance, financing, and sales planning. The cars are financed completely through sponsorship,

For a full, year-long racing season, the students put their studies on hold. Worldwide, around two hundred teams take part in the competition, which evolved from the Formula Student Combustion (FSC), a competition that began with combustion-engine cars.

To weld the car’s rechargeable batteries to their purpose-built carrier assembly, the eMotorsports Team Cologne from the Cologne University of Applied Sciences needed a cell welding machine with very high capacitance. So they approached Schukat with their sponsorship request.

From the resulting discussions, another topic emerged for which Schukat was happy to provide support: the need to optimize the battery charger. Previously, the car’s battery was charged using a bulky, expensive laboratory power supply that weighed in at around 25 kg and supplied a 600VDC output and 10A charging current. The goal was to speed up the charging process using the maximum charging current of 12A. The team also needed equipment that was easy to transport – for financial reasons, team members travel to the various events around the world independently and camp on site in tents.

Schukat backed the project in two stages: First, the company provided the student team with capacitors from manufacturer FTCap, which have a capacitance of approximately 2F. With these, the team built a cell welder to weld the round Li-ion rechargeable cells to a custom-built carrier assembly. In addition, the welding machine was made CNC-capable – during the forced racing break prompted by Corona.

Second, Schukat supported the team, as requested, with an advanced and powerful – but also compact and lightweight – charging technology for their home-made battery units (Fig. 2). These consist of standard, low-cost 2500mAh 18650 lithium-ion round cells that power four electric motors (one per wheel) via an inverter in the drivetrain.

 

To make the charging technology as easily portable as possible, it was to be installed in a trolley case that also held additional electronics (including additional power supplies such as the conduction-cooled Mean Well UHP-350-24 as an auxiliary power supply for extra peripheral devices). The very limited installation space meant using a compact charger, and due to the high packing density and despite fans to dissipate heat, it had to be efficient, with the lowest possible power loss.
Schukat therefore settled on the CSP-3000-250 unit from producer MEAN WELL. This can be used, for example, as a high-voltage power supply for industrial applications that need constant voltage, for constant-current LED applications, or, as here, as a battery charger.
The power supply provides a high-voltage output with a maximum of 250VDC; three units connected in series were employed for this application. By simply setting each power supply’s output voltage to 200VDC, the required 600 VDC charging voltage and 12A charging current was achieved precisely – enough to sufficiently charge the batteries in 30 minutes. The power supply can be operated at full power at up to 55°C ambient temperature in the electronics trolley case. The biggest advantages, however, are the reduced size and weight savings, with each CSP-3000-250 unit weighing just 4kg and measuring a compact 278x177x63.5mm.

• Can be operated as a stand-alone unit or in series or parallel configurations: As individual devices, the power supplies in the series deliver up to 3000W, and up to 9000W with three units connected in parallel, and offer the eMotorsports Team Cologne the option for even higher charging voltages in upcoming re-designs

• Highly efficient: Efficiency of 92.5%
• High application flexibility: Output voltage and current are easy to adjust to individual needs. The power supply also has a remote ON/OFF interface and DC-OK signal

• Protected against overload, short circuit, overvoltage and overtemperature, providing the race team with the best possible protection during competitions

• Cooled with a quiet, built-in DC fan

• Interface: analogue; other options for future charging technology re-designs have been discussed. Other MEAN WELL power supplies, for example, offer options involving integrated digital interfaces, allowing direct integration of the CAN bus used in the project. This was not required in this case, however.

With Schukat’s support, the eMotorsports team has significantly improved the performance of their existing system. Due to the Corona pandemic, however, neither the vehicle nor the charger could be put to use, and the team consequently focused purely on the development and simulation of new concepts. After this obligatory break, the team continued to develop and build: they developed their own battery management system, developed and assembled each circuit board, and also programmed the software themselves. The 6.47KWh battery was expanded from 576 to 720 cells. Such state-of-the-art technologies as recuperation with energy recovery of more than 18% and autonomous driving were also developed, tested and incorporated into the vehicle.
At rollout, the team – comprising 25 members from 11 nations – presented a finished vehicle with a top speed of 123km/h, 128kW of power, and 966Nm of torque. The car weighed 175kg, of which the carbon monocoque made up just 19kg. Unfortunately, the team was unable to take part in the only competition in 2022 in Spain because a special rim that, for aerodynamic reasons, completely encloses the electric motor could not be delivered or replaced in the short time available. Instead, the team continued to work on improving the aerodynamics, weight and performance of their "emC23" car for the 2023 season.

And the team has suffered another bitter blow: developments surrounding the war in Russia, inflation, and falling GDP mean that a number of sponsors have pulled out of participation in the project. Even the TH Köln faculty that has been involved up to now has unexpectedly reduced its funding. Price developments have resulted in sharp increases in internal costs, which can no longer be met by the available budget, and the necessary finances for the season are no longer certain. The racing team is now approaching other sponsors and faculties at TH Köln for funding to avert a complete stoppage of the project beyond 2023.

Students at the TH Köln have been constructing purely electrically powered racing cars since 2009, further developing the work and knowledge of the last "internal combustion team” of 2008. At the start, only a handful of students set off with this idea on the challenging journey. Today, the team comprises more than 20 members each season, who come together from different courses of study and organize themselves to build racing cars for Formula Student competitions. Driven by leading-edge innovation and dedication, continuous development in all areas of the car has been achieved year after year.

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