The electric race car of InMotion. Image: Charlie Acuna
In November 2022, InMotion started with over 30 students to design and produce their new battery pack for the race car. What is remarkable is that this battery pack charges in just 3 minutes and 56 seconds, with a charging power of 322 kW, a total capacity of 29.2 kWh, and a range of approximately 250 kilometres. Reducing the charging time for electric cars is important to make electric driving more convenient and more accessible for consumers. InMotion is taking up that challenge and is now getting very close to a pitstop-worthy charging time.
Innovation
During fast charging, a significant amount of heat is generated, leading to accelerated degradation, explains Julia Niemeijer. “In the past, we have developed an innovative cooling technology at module level, where cooling plates filled with cooling liquid are placed between the battery modules. This allowed us to already extract a lot of heat from the pack. If you want to extract the heat from the battery pack as much as possible, you will need to have your cooling system as close as possible to the cells. Therefore, for the last years, we have developed a method that enables cooling at cell level, with actual cooling liquid flowing between each cell. This means we can extract even more heat from the pack, which has a tremendously positive effect on the lifespan and repeated fast charging. In a 24-hour test, degradation was found to be minimal.
Cell-level cooled battery modules are not yet common on the market, which is why InMotion has developed their own modules. Niemeijer: “It was quite challenging because there was only a few millimetres of space between the cells in the module to implement cell-level cooling. This required very precise engineering. We are extremely pleased that we have found a method that makes this possible.”
Inspiration
The goal of InMotion is to showcase that it is possible to bring the charging times of electric vehicles down, to a level that is comparable to the time it takes to fuel a petrol-powered car. With this technology, they hope to make electric driving more attractive for the consumer and to challenge the industry to make the world greener. If a team of highly motivated students is able to create this, then the industry has no other option than to follow the students.
“Student teams such as InMotion are important to, triggered by a challenging application in this case an electric race car, push boundaries and try to put new technologies into practice. Being able to charge the batteries of an electric vehicle faster is not trivial and is important for a faster acceptance in the market, where innovations like a bettery pack with extremely optimized cooling will play a key role”, says Henk Jan Bergveld, part-time professor Electric Engineering at Eindhoven University of Technology.
Implementation
The technology has been tested at the Dutch research institution TNO and technology company Prodrive. “The beauty of the technology is that it is possible to make battery packs of different sizes”, explains technical manager Stijn van de Werken. “It is often thought that smaller battery packs can charge faster than bigger packs. However, that is not the case. The charging time will stay the same, regardless of the size of the pack, as long as the charger can give enough energy. This principle makes it possible to have an endless amount of opportunities for implementation.”
The student team has implemented the technology in a LMP3 race car. The LMP3 is a prototype class in the iconic 24 hours of Le Mans, intended for young racers and new teams to start with the race. Van de Werken: “In the coming year we will thoroughly test the race car on circuits.” The ultimate dream of InMotion is to showcase the technology during the 24 hours of Le Mans, to test the battery pack in the toughest race conditions there are, which is endurance racing.
