BMW Launches Inductive Wireless Charging for HEVs

The automaker’s inductive system has a charge rate of up to 3.2 kW, and fully charges in around 3.5 hours.

 

By Murray Slovick, Contributing Editor

BMW has launched a wireless-charging system for its plug-in hybrid vehicles. The factory-fitted, fully integrated inductive charging system, said to be a world’s first, can be ordered now as a leasing option for the BMW 530e sedan.

BMW Wireless Charging employs the same inductive charging technology already widely used for supplying power to devices such as mobile phones and electric toothbrushes.

Figure 1: BMW says its GroundPad inductive charger can be installed outside, and won’t be damaged if driven over.

 Using a base pad placed on a parking space and plugged into the power source, the system can be installed in a driveway or in a garage (Fig. 1). It needs to be connected to a 240-V outlet to work. The charging process starts as soon as the vehicle is parked in position over the pad.

To do so, a Wi-Fi connection between the charging station and the vehicle is first established. An overhead view of the car and its surroundings then appears in the Control Display (Fig. 2) with colored lines that help guide the driver.  The car’s position can deviate from the optimum position by up to 7 cm longitudinally and up to 14 cm laterally. Green circles appear when the vehicle is perfectly aligned. Charging starts automatically, the moment the ignition is turned off.

Figure 2: The car’s control display helps the driver properly line up the pad.

The contactless transfer of energy between the GroundPad and the CarPad (installed under the car) is conducted over a distance of around 8 cm.  In operation, the GroundPad generates an alternating magnetic field. Meanwhile, in the CarPad, an electric current is induced, which then charges the high-voltage battery at a charge rate of up to 3.2 kW. This form of power supply to the high-voltage battery involves a charging time of around 3.5 hours and has an efficiency rate of around 85%.

The GroundPad can be installed outdoors, where it may be used regardless of the weather conditions. All components that conduct electricity are protected from rain and snow, and BMW says that driving over the GroundPad will not damage it in any way. During charging, ambient electromagnetic radiation is limited to the vehicle undercarriage.

The principal benefit here is ease of use, as drivers no longer need to hook up their plug-in hybrid car using a cable in order to replenish its energy reserves. The driver can simply step into the car and pull away at any time without unplugging or stowing a plug and cord.

The system automatically shuts off when it recognizes the car is fully charged. An app keeps the driver informed of charging progress, and will alert the driver to any disturbances to the process, such as a pet resting on the pad.

Production and sales will start in July in Germany; the product will subsequently be offered in the U.K., U.S., Japan. and China.

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