Porsche Taycan And The 100 Percent Performance Criteria

Slowly we learn more about the Taycan, Porsche’s first electric sports car. The Taycan is expected to be hit the market in late 2019, and so far 100 cars have been produced. Those are being tested heavily, including tests in South Africa at temperatures of around 40 degrees Celsius (104 Fahrenheit).

And that is necessary, as the behavior of the Lithium-Ion-batteries has to be tested and guaranteed. Batteries are temperature sensitive and can give constant power over a longer period only if their temperature is tightly controlled. Tesla famously restricts the speed once the batteries are getting too hot.

Now we have to know that Porsche’s philosophy of what car is allowed to get the Porsche seal, is a criteria that they call Volllastfähigkeit (100 percent performance). If a car can keep the power once you put the pedal to the metal for 30 minutes, then this criteria is fulfilled.

How do you manage that with an electric sports car? By cooling the hell out of the batteries. And that turns out not being that simple, as Porsche had to experience. It starts with Porsche’s mother company not allowing them to use battery cells like the ones that Tesla is using, but cells that are much larger. While Tesla’s Model S has a little bit over 7,000 pieces of the 18650 cells in the battery boxes, Porsche uses around 400 cells in each car. While former ones can be temperature controlled with tightly wrapped cooling hoses, that becomes more difficult with larger cells. The temperature is supposed to be between 20 to 40 degrees celsius (68 to 104 Fahrenheit) for optimal performance, and this can only be achieved with increased effort. And even then not completely, as there will be local heat spots in the cell, which cannot be reached fast enough by the cooling system.

That’s why Porsche has equipped the Tacan with two radiators for two cooling systems; one that is below the battery pack, and another that’s above it. Like in a sandwich the battery is between the cooling systems. And that means two radiators, in addition to the one for the air condition. And where do you put them? In the engine room. Which tells us that there won’t be much of a frunk in the Taycan.

Porsche_Battery.jpg

Whether this effort will give the Porsche Taycan 100 percent performance is probably what Porsche is testing heavily. And what this means for the lifecycle of the batteries, when driven to the extremes and creating local heat spots, is something we can only speculate for now. Three radiators in the car mean one thing for sure: the range of 500 kilometers (310 miles) according to NEFZ will not be reached, because the radiators have to get their energy from some place. And that’s what they – like may other systems – are also getting from the battery.

And that could mean that the Porsche Taycan won’t be able to reach the 30 minute 100 percent performance. The car may have cool batteries, but not enough juice left to run for that time. Anyways, we are excitedly waiting for the results.

So far we haven’t mentioned the fast charging, which brings the car to 80 percent within 15 minutes with the 350kW superchargers. And here as well the temperature has to be regulated and the batteries may suffer from it.

After production hell started for the Audi e-tron, the Mercedes EQC debacle, now Porsche is facing its own time of truth. Turns out that Tesla has set the bar quite high for traditional carmakers.

This article was also published in German.

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