Porsche has built “3 figures worth” of prototypes of the upcoming 600 hp electric Taycan sports car (formerly known as Mission E earlier post), which is due to be released next year. Porsche is currently projecting roughly 20,000 units per year—approximately two-thirds of the current sales figures for the 911.
Two permanently excited synchronous motors (PSM), like those deployed in the Le Mans–winning 919 Hybrid, generate a permanent rotary motion that can be applied at any time without needing to be started—a technical feat achieved by having a permanently magnetized rotor forced into a rotary motion by the magnetic field of the stator.
We opted for a permanently excited synchronous motor in the Taycan. They combine a high energy density with strong sustained performance and maximum efficiency.—Heiko Mayer, drive unit project leader
PSM electric motors are the turbos of the electric motor milieu. They boast both extremely high sustained performance and maximum efficiency. One motor powers the Taycan’s rear axle, the other the front wheels. Together they generate more than 600 hp (440 kW) and are fed by batteries designed to provide five hundred kilometers of range.
The Taycan accelerates from 0 to 100 km/h in well under 3.5 seconds and tops 200 km/h in less than 12. The PSM drives convert electrical energy into power with great efficiency, smoothness, and sustained output while generating relatively little heat. The electric drive Porsche is track-ready as well.
The PSM motors also enable a very compact design, making it possible to make the motors and batteries smaller and lighter with the same power figures, Mayer said.
To save even more space, the electric motors’ solenoid coils feature a hairpin technology design. This makes it possible to pack the wires more tightly and get more copper into the coil machines—increasing power and torque with the same volume, explained Naser Abu Daqqa, director of electric drive systems at Porsche.
The Taycan’s power electronics are also fine-tuned for efficiency. The inverters that convert the battery’s direct current into alternating current for the electric motor don’t work with a fixed pulse frequency as is common, but with a steplessly variable pulse frequency. The motor always runs at the optimal operating point, said Mayer.
Temperature sensors detect the cooling requirements in real time, while software ensures that the cooling water is immediately directed to the right spots. If the driver floors it, the cooling kicks into high gear as well, ensuring constant power.
Batteries. Rather than installing heavy batteries, Porsche is opting for fast charging. Electricity flows through some four hundred cells, which are connected both serially and in parallel. Each individual cell has a current of roughly 4 volts. Controlled by the battery management system, this all amounts to the 800-volt battery.
It was a major challenge to achieve such enormous battery capacity both for charging and discharging over the entire temperature range.—Nora Lobenstein, head of all energy storage systems at Porsche
The solutions are an intelligent charging protocol and an efficient heat exchanger system that quickly gets the batteries up to operating temperature and reliably cools them under heavy loads—for example, during a sudden spike in power usage or during rapid charging.
The objective of the Porsche fast-charging system is 400 kilometers of range in about fifteen minutes. Aside from the short travel breaks for charging, another payoff of the 800-volt technology is the thinner cables in the car. That also saves weight.
Porsche developers are also already studying how the Taycan’s batteries can be reused in the future.
Charging. The company is pursuing three options for charging the Taycan: First, charging at home with a charging station or inductively via a base plate in the floor. Second, charging in cities through existing infrastructure. Third, charging along the main traffic arteries in Europe.
The joint venture Ionity was formed to provide the infrastructure to support that last option. Together with the BMW Group, Daimler AG, the Ford Motor Company, and the Volkswagen Group with Audi, Porsche is laying the groundwork for the establishment of a powerful fast-charging network for electric vehicles in Europe.
Every Ionity fast-charging park will have multiple charging points. They ensure that a vehicle can be charged every 100 to 150 kilometers along the European road network. As the number of electric vehicles grows, so too will the infrastructure. Thus by 2020, customers will gain access to thousands of brand- and capacity-independent “high-power charging” (HPC) points. The charging capacity of up to 350 kilowatts per charging point enables accordingly designed vehicles to achieve significantly shorter charging times compared to the systems available today.
“Plug in and charge fast” is the motto. Payment is completely automatic. Porsche and its development subsidiary Porsche Engineering are pursuing a modular in-house concept for ultra-fast charging parks. Whether it’s individual stations in the countryside or dozens of charging stations along highways: the solution is an intelligent system with practically unlimited scalability.