FP7 UNPLUGGED project - inductive charging for electric vehicles
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Background

Today electric vehicles (EV) are having a hard time being accepted by the customer and diffusing in the market. Even though many aspects of EVs seem making them very appealing (e.g. very low energy cost and zero tail pipe emissions) there are several concerns that people have on this technology:

  • Range anxiety: Because of the limited range of EVs caused by the current relatively low capacity of batteries, the freedom of the driver, one of the major reasons to own a vehicle, is limited
  • EVs require a significantly higher initial investment cost than vehicles with common combustion engines due to the high cost of the energy storage (battery)
  • The EV batteries need to recharge frequently and hence the driver has to find a suitable recharging stations and has to plan the routes accordingly

The charging process itself is very time consuming and hence user-unfriendly

Inductive charging

This offers several advantages over the conductive (using a cable) charging method:

  • It is easily operated and comfortable due to the automation of the charging process
  • Since there is no need to plug-in a cable the driver will not have to get out of the car and get his hands dirty especially in rainy, snowy or muddy environments (which also do not affect the wireless inductive charging process).
  • There is no risk that the user forget to plug in the vehicle at the end of the parking, losing the capability of a fit range for the following use of the car
  • The system is safe against vandalism, misuse/abuse and environmental influences (e.g. humidity) because all devices are encapsulated in the vehicle and the ground
  • There is no negative impact on the cityscape (all devices are hidden in the ground)
  • Without having to manually connect the vehicle to the grid the availability of the EV for vehicle-to-grid applications (V2G) is higher (e.g. for using the vehicle’s battery to store excess energy in the grid)

These above mentioned advantages already prove the usefulness of (stationary) inductive charging compared to the currently more common conductive charging infrastructure. However inductive charging will offer many more possibilities in the future, especially concerning en-route charging.

The potential of inductive en-route charging

With inductive en-route charging, EVs could be charged while standing at the traffic light, the bus stop or the taxi stand while it should be impracticable with the conductive charging option. So, using wireless inductive charging, these short timeframes could be used to charge the EV and hence its range. The charging method above is called static inductive en-route charging because the vehicle is standing still while charging.

In addition, there is also the possibility to charge the vehicle while it is actually moving. This charging method is called dynamic inductive en-route charging. This charging method holds the potential of giving the driver virtually limitless range as long as he stays on paths specifically adapted for dynamic inductive en-route charging. This could lead to a reduction of battery size or the use of capacitors which would both lower the weight and the cost for the vehicle. The impact on the infrastructure has to be taken into account, so it has to be evaluated if or when, dynamic inductive charging is needed and preferable to only static inductive charging.