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Batteries in the laboratory test: VW ID.3 against Tesla Model 3

The TU Munich has developed a standardized test procedure for e-car batteries. In the first duel, Tesla has the edge. VW loads and steers more carefully.

Do two batteries of the same "size" from Tesla and VW actually offer the same performance in their respective cars? The Technical University of Munich has developed a standardized test to compare batteries. Together with auto motor und sport, the Munich researchers Matthias Steinstr├Ąter, Markus Lienkamp and Nikolaos Wassiliadis compared the batteries in the ID.3 and Model 3, which have a net capacity of 55 kWh and are the same size. The 13-strong research team had the cars drive identical routes under the same weather and temperature conditions on the dynamometer at the Technical University of Munich and in real operation. A city cycle (around 8 kilometers) was driven at an average speed of 25 km/h. In addition, an overland cycle (20 kilometers) with an average speed of 50.6 km/h. As well as a 35-kilometer motorway cycle with an average speed of 93.7 km/h. The result: In practice, the battery in the Tesla lasts a little longer than in the ID.3, although the Tesla with 239 kW is almost twice as powerful as the ID.3 with 125 kW.

Better efficiency with Tesla

A disadvantage in the VW is that the engineers start cooling the ID.3 from a battery temperature of 33 degrees, in the Tesla only from 42 degrees. This saves a lot of energy for cooling in the Tesla. According to the Munich researchers, Tesla uses the more modern power electronics, an inverter with silicon carbide technology. in the ID.3, on the other hand, an inverter with insulated gate bipolar transistor technology is used. Overall, the ID.3 can only partially compensate for Tesla's lead with lower rolling resistance. The VW only has a longer range at an ambient temperature of 15 degrees on country roads, otherwise the Tesla is always slightly ahead, with a range of up to ten kilometers more. The longer range is also due to the fact that Tesla uses energy more efficiently and has significantly lower air resistance. With the Model 3, the efficiency under full load is 97 percent, with the ID.3 only 93 percent.

Incidentally, the higher permissible battery temperatures for the Tesla are also noticeable when charging. Tesla expects the lithium-iron-phosphate battery to have a maximum temperature of 50 degrees when charging, VW allows its lithium-nickel-manganese-cobalt cell to be just under 45 degrees. The result: while the Model 3 can be charged from 10 to 80 percent in just 26 minutes with quick charging, the ID.3 takes 35 minutes. In order to be able to assess the quality of the battery cells from VW and Tesla even more precisely, the TU Munich has procured its own cell packs from VW and Tesla, which are currently being subjected to intensive tests in the laboratory. auto motor und sport will publish the results in early 2022.

All details on the standardized test procedure of the TU Munich and the detailed measurement and test data can be found in Issue 23/2021 of auto motor und sport. The issue is available here as an e-paper .

Conclusion

In a direct comparison, Tesla can use its many years of experience. Despite the supposedly simpler cell chemistry (LFP), the Model 3 allows higher battery temperatures, processes the energy more efficiently and is therefore more practical than the VW despite the significantly more powerful electric motor. The good news for VW fans: The Wolfsburg-based company managed to catch up quickly and still has plenty of potential for further development. Matthias Steinstr├Ąter is convinced that VW can, for example, significantly increase the charging capacity by so-called preconditioning of the battery before fast charging. This is already being worked on in Wolfsburg.

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