New Porsche Taycan: tech insight into the brand's first all-electric car

An all-electric Porsche? I have to pinch myself as I climb into the Porsche Taycan for my shotgun ride around the carmaker’s Düsseldorf test track. Is this a sign the electric-vehicle (EV) revolution has truly started? There is not much time to philosophise before the Porsche test driver mashes the accelerator and my head snaps back against the headrest. The 1 050 N.m instantly delivered to all four wheels is enough to churn one's intestines. The first corner approaches fast and the pilot flicks the car into an almighty drift that would make Ken Block proud: four wheels spin fiercely and the car almost slides in reverse because of the excessive slip angle. Somehow, the Taycan straightens out and the ferocity of the acceleration hits home once more. Yes, this is a hyper-performance, eerily silent Porsche…

The technical workshops preceding the track experience gave me the opportunity to spend time with the key development engineers responsible for this ambitious project and learn what it took to create an electric sportscar worthy of that famous crest on the nose.

 Body

The body-in-white (BIW) is manufactured from a combination of aluminium and high-strength steel, with the battery casing adding rigidity when married from underneath. The vehicle’s size sits between a 911 and Panamera, with a distinctively lower nose section than the latter. This is because the lack of an internal-combustion engine means pedestrian protection can still be achieved although Porsche also decided to include a pyrotechnic pop-up bonnet for good measure. The drag coefficient of 0,22 Cd is class-leading and the active aero (wing at the back and dynamic ride height) is tuned while driving to achieve the least amount of drag.

Chassis and suspension

We’re seeing a general trend emerging in the layout of high-performance EVs: one electric motor on each axle with the lithium-ion battery pack housed in the floor between to keep the centre of gravity low. This platform is termed a “skateboard” and fits underneath the body structure. We would not be surprised if it is dimensionally scalable to spawn other all-electric Porsches (a little birdie told us there is an electric Macan in the not-too-distant future).

Porsche borrowed many components from the Panamera but some had to be modified to fit the space constraints of the Taycan. Three-chamber air springs can lower or raise the body by 22 mm. The firm’s electric anti-roll bars (PASM) are also used to great effect; in combination with the low COG, there is absolutely no body roll during cornering.

Battery and charging

Porsche employs a 93 kWh lithium-ion battery pack consisting of 396 pouch cells. This is enough energy for a range of 412 km on the new WLTP emission cycle (more conservative than the NEDC) and a maximum power output of 620 kW. The pack weighs 650 kg and is temperature controlled for optimum performance.

The battery provides direct current (DC) but the electric motors need alternating current (AC) to operate. Therefore, an inverter is used at each motor. The high power (current and voltage) demands require special semiconductor switches in the inverters to handle the electric load.

The Taycan has two charging ports, one on the left and the other on the right-front flank. This is to differentiate between standard household charging and fast charging. The Porsche system’s voltage is 800 V, a first for an production EV where 400 V is more common. As electrical power equals volts times ampere, the result is thinner (and lighter) cables can be used. As the charging speed is a function of battery temperature, Porsche developed a planning function; while you drive to a charging station, it conditions the battery to speed up the process.

Powertrain

To achieve blistering performance figures, the powertrain must be able to produce the power and grip needed to catapult the vehicle down the road.

Electric motors

Porsche decided on permanent-magnet, synchronous-motor (PSM) technology compared to the more common and less expensive asynchronous motor. The advantage of PSM technology is higher power density and improved cooling, which allows the motor to be more compact and deliver higher continuous performance.

Dynamic prowess and grip during straight-line performance require more power on the rear axle (seen in the table below). Both electric motors are watercooled to increase efficiency and allow continuous high performance.

Transmission

The immense torque produced by an electric motor from almost zero engine speed, combined with the high maximum rotational speed, mean there’s little need for a multi-speed gearbox as with an internal-combustion engine (including no clutch requirement). Therefore, Porsche engineers decided on a single ratio for the front axle with gearing allowing a top speed of 260 km/h at 16 000 r/min (electric motor rotor limitation). As the motor is of the co-axial type, it is located in line with the axle providing drive through the single-speed transmission and differential to the front wheels.

As the initial part of the torque curve of an electric motor consists of a constant torque region (followed by a constant power region), it is possible to use torque multiplication to increase the tractive force during acceleration while sacrificing top speed. Porsche engineers decided to employ a two-speed transmission on the rear axle to achieve the target of a 2,8-second 0-100 km/h time. It is clear from the graph the traction force is optimised before entering the constant power region of the electric motor up to the top speed of 260 km/h. A lower first gear would result in wheel spin; a higher second gear ratio (or third gear) is needed to achieve a higher top speed (including a similar change to the front-axle gearing).

When performance is not paramount, efficiency is the main objective. The Taycan reverts to front-wheel drive during cruising or other light-load conditions. In this mode, the rear electric motor is scaled back to zero torque so as not to cause a drag force on the vehicle and upset the handling balance.

Interestingly, a separate parking brake mechanism is not needed, as a Porsche engineer found selecting both first and second gear at the same time locks the rear axle solid (because of the conflicting ratios) which serves the same function.

Brakes

The Taycan’s mass of 2 295 kg demands gigantic 420 mm discs up front and 410 mm discs at the rear. However, mechanical brakes are rarely used in general driving when brake energy recuperation is employed by the electric motors. Porsche is against the idea of single-pedal driving (accelerator features a heavy regen function when lifting off) and has moved both the electric recuperation and mechanical brake operation to the brake pedal only. Brake pads should therefore not need changing due to wear, but Porsche recommends they be changed every five years.

Interior

The interior follows the current Porsche styling trend found in the latest Panamera. Porsche traditionalists will bemoan the deletion of the central rev-counter but appreciate the configurability of the digital instrument cluster now high on the dashboard. It almost takes the place of a head-up display as it is in line of sight of the driver. An interesting additional touchscreen option in front of the passenger enables them to operate functions like the satellite navigation and audio selection.

The sound

The lack of noise is something petrolheads will need to get used to. Porsche will provide an optional soundtrack that mimics a V8 (sort of). According to the test driver, it’s useful feedback when the wheels start to break traction while accelerating out of a corner (traction control switched off). An external speaker warns pedestrians and communicates the “V8” soundtrack to bystanders.

Fast facts

Porsche Taycan Turbo S
Electric motors: permanent-magnet, synchronous, one per axle
Transmission: 2-speed auto on rear axle; 1-speed on front axle
Power: 460 kW (560 kW on overboost) combined
Torque: 1 050 N.m (combined)
0-100 km/h: 2,8 seconds
Top speed: 260 km/h
Electricity consumption: 26,9 kWh/100 km (NEDC)
CO₂: 0 g/km (local)

Original article from Car