At the 32nd Electric Vehicle Symposium last month in Lyon, France, experts from Continental‘s powertrain business gave presentations on innovations for a more efficient electromobility.
As the general interest in electromobility and electric vehicles (EVs) is on the up, the company believes it is important to ensure that using an EV is practical on a day-to-day level.
Thermal Management on a system level, for instance, can help to achieve a considerably longer vehicle range despite cold or hot ambient temperatures.
Solutions for fuel cell vehicles can provide an answer to long distance driving, especially for larger and commercial vehicles.
Continental now uses artificial intelligence (AI) and the principle of swarm intelligence to design optimum fuel cell systems.
The demand for higher power density in electronics, with greater power levels and more functions integrated into ever smaller packages will only increase, particularly for smaller EVs and plug-in hybrids.
New semiconductor materials such as gallium nitride (GaN) are potential solutions which enable such high integration, for example in bi-directional on-board chargers.
“Electric vehicles, hybrids and fuel cell vehicles will all be an integral part of the future mobility mix. As they offer a new experience to drivers, it is important to get the vehicle practicality right,” said Stephan Rebhan, Head of Technology & Innovation Powertrain.
“This extends far beyond driving. To make electromobility a success, we must also address the trickier bits, which can spoil the fun of driving, if left unattended.
“Thermal management and efficient charging rank high on that list because they can add to the usability of driving an EV.”
Every proud new EV owner is in for an eye opener when the first winter season approaches in the northern hemisphere: At below 0°C temperatures, the range of the vehicle can be much smaller than at 20°C. Therefore, it is important to reduce this temperature-induced loss to a minimum.
Continental’s Thermal Management research vehicle is equipped with specifically developed multi-port Coolant Flow Control Valves (CFCVs), coolant pumps and the newly developed Electro-Thermal Recuperator (ETR) or smart heater.
Working together, these components harvest heat and energy where it originates in the vehicle and transport it to places where it is useful. By doing so, the energy demand from the battery is reduced, which increases range.
Depending on the temperature level of core components such as the battery, the heat flow can be flexibly re-directed as needed.
The smart heater, for instance, can help to either heat up the cabin or the battery when it is too cold for the battery to accept electric energy from recuperation (regenerative braking). The smart heater will turn electricity into heat that is available for appropriate use.
“In an EV both, human and machine, want to be in their comfort zone”, Rebhan said. “A car that is equipped with our smart heater, for instance, can achieve the comfort zone in a third of the time of a model without a smart heater.”
Gallium nitride, due to its lower conduction and switching losses is a compelling technology for power electronics.
For example, GaN in a bi-directional, air-cooled on-board charger enables charging efficiency of 95%, thus reducing charging times and increasing overall energy efficiency, which in turn improves the practicality of electrified vehicles.
A fuel cell powertrain is rather complex to design: It consists of two electrochemical power sources (i.e. the fuel cell and battery) which are connected via at least one DC/DC link to the inverter and the electric motor.
Getting the maximum efficiency out of the powertrain means finding the best operating strategy and power split between the fuel cell and the battery.
The Powertrain Division is using AI and Pontryagin’s Minimum Principle (PMP) optimisation algorithms to compute the optimum fuel cell system and powertrain design for a known drive cycle.
By harnessing its AI and swarm intelligence know-how, the fuel cell experts were able to lower the energy losses in the battery-DC/DC link by around 3.5% through finding and applying intelligent control principles.