Continental to show EV battery charging systems at CES
Two new Continental battery charging systems for electric vehicles will be presented at next month’s Consumer Electronics Show in Las Vegas. The first of these is an automatic wireless charging system and the second is known as AllCharge and aims to optimise the compatibility of cable-based systems.
Continental’s automatic wireless charging system operates inductively, transferring charging power wirelessly from a ground-based charging pad to a receiver pad on the underside of the vehicle. Since this method of charging requires the vehicle to be precisely located over the ground pad, Continental has also developed a micronavigation solution that uses a magnetic location system to position the vehicle up to ten times more accurately than a conventional parking assistant could.
Charging takes place fully automatically, with continuous safety monitoring performed throughout the charging process. This inductive charging system is said to be more than 90 per cent efficient. Designed for a charging rate of 11 kW, a car’s driving range can be increased by up to one kilometre for every minute of charging.
Future versions of the system will be able to automatically ‘repark’ automated electric vehicles as soon as charging has been completed, allowing a succession of vehicles to be charged overnight at a single charging station. As Continental participates in international standardisation efforts, the hope is that all makes of vehicle will be able to use all inductive charging stations.
AllCharge – turning the powertrain into a charger
The cost involved in setting up direct current cable-based electric car charging stations is high. Therefore, most stations in use today offer alternating current charging, with the AC/DC conversion occurring on board the car. Yet locating the converter equipment on-board is becoming increasingly problematic due to rising demand for higher charging rates. With the AllCharge system, Continental’s engineers have adopted a completely new approach, one they say is incredibly simple: instead of cramming even more charging technology into the car, they have turned the electric powertrain itself into a ‘charger’.
To do this, the electric motor and the inverter (which is used for converting between DC and AC power) were adapted to enable them to support the additional task of charging. The only extra component involved in this system is a DC/DC converter, which ensures a flow of power to the battery at the optimal voltage level at all times. In the case of AC charging, the current flows from the charging station via the electric motor to the inverter, where it is converted into DC current before being supplied to the battery. In the case of DC charging, the current flows directly through the DC/DC converter to the battery.
AllCharge therefore serves as a kind of universal pass key that enables drivers to use any cable-based charging station. And since AC charging is no longer affected by the limitations of an on-board charger, if appropriate AC infrastructure is available AllCharge can charge the battery at a rate of up to 43 kilowatts, providing up to 50 kilometres of driving range in just ten minutes of charging time. The Continental system is also compatible with both 400-volt DC and 800-volt DC fast-charging stations; the former can supply up to 150 kilometres and the latter can give vehicles with very large batteries up to 300 kilometres driving range in ten minutes of charging time. This brings charging time closer to the time required to refuel a conventional vehicle.
In addition, the AllCharge system makes it easy for a car to double as a power bank as it comes with pre-integrated with bidirectional capability, with AC current able to be supplied without upper output limit.
Continental anticipates commencing volume production of its AllCharge system in 2022.