The electrical system of the Taycan works with an unusually high voltage of 800 volts. The voltage in the auditorium of the annual Automobil Elektronik congress in Ludwigsburg was just as high when Porsche’s top electronics developer Uwe Michael appeared: after all, the vehicle was not to be presented before the IAA 2019 (12-20 September, Frankfurt). How far would Michael open the lid of the Taycan electronics compartment?
When designing the vehicle, Porsche engineers paid particular attention to six aspects: electronics architecture, high-voltage network, battery, charging processes, the so-called Smart Functions and an area that Michael labelled “Additional Highlights”.
The electronics landscape of the Taycan is surprisingly conventional – no futuristic central computer with virtual ECUs, as it is currently discussed in the automotive industry. Instead, it consists of more than 100 function-specific ECUs, which (at least) are networked with each other via a central Ethernet backbone. The future comes via the central gateway into the car, because the entire software can be updated via data download over the entire life cycle of the electric sports car. This functionality made a security concept for all levels of the architecture a mandatory prerequisite. Michael frankly admitted that this development was not an easy undertaking. “We had underestimated the complexity,” he sums up.
The OTA (Over-the-Air) updates offer a wide range of functions – from simple updates for the navigation map to warranty functions such as bug fixes, unlocking features or downloading completely new functions. Under the buzzword “Function on Demand”, Porsche intends to continue to offer future customers new functions after the purchase and to bring them into the car via OTA download.
The Taycan’s high-voltage system comprises more than ten subsystems. The front and rear axles are each driven by their own electric motors with attached control electronics. In addition, the Taycan has the most powerful heater in its class with more than 10 kilowatts. It not only serves the comfort of the occupants, but also keeps the battery at optimum operating temperature. A special DC/DC converter with 48 V output voltage is available for controlling the actuators in the chassis. A real novelty is the HV booster – if necessary, it increases the input voltage at the charging plug from the widely available 400 to the still rather exotic 800 volts. “This makes us more independent of the charging infrastructure,” explained Michael.
Higher voltage for less weight
By the way, Porsche relies on motorsport experience for the high-voltage battery – in Le Mans the company did not send an electric vehicle to the 24-hour torture, but it did send a plug-in hybrid, with: exactly, an 800-volt battery. Developed together with LG, the battery for the Taycan will be produced in Poland. Four operating modes are available for charging: The standard method on the domestic wallbox with 11 kW alternating current, the option with 22 kW and also alternating current as well as the direct current variants with 400 Volt and 50 or 150 kW as well as the maximum variant with 800 Volt, which is intended as the standard operating mode and requires a full 350 kilowatts from the charging station. Michael told the engineers, however, that they should be prepared for the fact that the charging infrastructure backend is not always fully up to requirements of fast-charging Taycans.
This leads to the question: Why on earth, 800 volts? Yes, because of faster charging. But there is another interesting aspect: Because of the cable diameters. The higher voltage makes thinner wiring possible. “This enables us to save dozens of kilograms in weight,” says the Porsche mastermind. And, last but not least, what about the “Additional Highlights” that Michael announced at the beginning of his presentation? What is meant here is a Burmester sound system that will probably be second to none: It has more than 1000 watts of output power, contains 21 amplifiers and, according to Michael, “it withstands fast curves.”