One of the problems with electric vehicles and plug-in hybrids is just that: they have to be plugged in. It’s a simple yet extra step that often times falls victim to human nature, i.e. we forget or become lazy about it. It’s the same thing we do with our phones, only waking up having forgotten to plug in the car is somewhat more debilitating than that. BMW is exploring a way to cut out the middle man with wire-free inductive battery charging.
Inductive charging re-energizes an EV’s battery with a magnetic field rather than a wire from car to power source. It’s achieved by fitting a primary coil in a floor-plate over which a car can park and a secondary coil on the underside of the car itself. An alternating magnetic field is generated between the two coils, which creates electricity that is then sent to the BMW’s on-board battery.
At a charge rate of 3.3 kW, the battery of a BMW i8 can be charged in under two hours, which is about the same amount of time as it takes the current wired recharger. Down the line, a 7kW rate will be able to charge the larger batteries of an all-electric vehicle, like the i3, overnight.
If generating a magnetic charging field in the garage near where people sleep sounds a little ominous, BMW states that the inductive charging system’s field strength falls well below regulatory limits. The electromagnetic radiation it produces is lower than a kitchen hotplate, too.
A parking assist in the electric BMW will tell drivers where to park on the pad to get the juices properly flowing. Charge starts automatically once the coils are properly aligned, provided nothing that can obstruct the power flow has ended up on the charging pad. We’re talking foreign objects here, though, not weather; the inductive system will work fine in rain or snow.
It may not seem like a big deal, but going wireless doesn’t only mean making things easier around the home. Inductive charging can make uncluttered, damage-prone public charging stations more of a common thing, which in turn makes a world full of electric vehicles much more attainable.