The condition of the battery in used e-cars is crucial for a reliable used car purchase. So far, mileage and durable thermal management for the battery were mainly criteria for used electric cars. The Munich start-up Twaice is campaigning for more transparency in the evaluation of used batteries. In a short interview with Lennart Hinrichs (Commercial Director of TWAICE Technologies GmbH) we take a look at the projects for evaluating used batteries.
gcm: According to Twaice, the digital twin of a battery should make precise statements about the condition of the battery and the expected remaining service life. How can you get information about the real condition of a battery from the digital twin?
Lennart Hinrichs: The exciting thing about the digital twin is that it uses data from the battery to determine not only the condition of the battery, but also its remaining life. So how many kilometers or years you can still drive with this battery. If you consider that the battery accounts for 30 to 50% of the cost of an e-car, it quickly becomes clear why this is essential information when buying a used car. If you do not have this information, you have to assume the worst case and in most cases the seller will receive significantly less money than would be justified.
But to come back to your question: On the basis of the battery data that are created by each system during operation, we calculate the current status and the remaining service life with the help of a combination of battery knowledge poured into algorithms and artificial intelligence. The charm of this approach is that forecasts are automatically validated and at the same time become more and more accurate over time.
Measurement data from the battery serve as the basis for Twaice
gcm. TÜV Rheinland and the Munich start-up Twaice are planning more transparency in the condition of the battery in an electric car. What information can be obtained with the new method?
Lennart Hinrichs: Usually, our software is currently mainly used by manufacturers, be it in the power tool sector or for trucks. Our project with TÜV Rheinland differs from this in that a fleet is monitored without a manufacturer being involved. In doing so, information from the battery is collected, from which we can calculate performance parameters.
The basic idea behind the development of our software was that we only use measurement data from the battery that is already available in a standardized manner, i.e. current, voltage and temperature. Of course, this information does not help you any further per se. But we can use this data to calculate the state of the battery and future performance. That means what capacity and performance the battery currently has and how this will develop in the future. That might sound trivial at first, but these values differ significantly depending on how the vehicle was used. The stress factors are very diverse and differ in their effects. For example, frequent fast charging, i.e. a lot of energy in a short time, is more damaging than slow charging in medium states of charge.
gcm: On the basis of the determined database, for example, warranty claims are to be checked in the future or a battery label is to be offered that guarantees the independently tested quality of the battery. What plans will be implemented in the coming years?
Lennart Hinrichs: Exactly right. We are currently in the test phase. In the coming months we will be specifying the offer. But in principle, the combination of leading software and the reputation of TÜV Rheinland is incredibly valuable in my opinion and will not only be important to end customers, but also to fleet operators and even manufacturers.
gcm: Thank you very much, Mr. Hinrichs.
Interview from February 2020
Cover picture - Lennart Hinrichs (Commercial Director of TWAICE Technologies GmbH) - Copyright Twaice
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