Tuesday, August 18, 2015
Seductive Inductive Charging
You’re seeing this technology evolving with smart phones and other small portable appliances like electric toothbrushes: the ability to charge an electrical appliance without having to plug it in. It’s called “inductive charging,” and simply put it’s using an electromagnetic field to transfer energy from one device to another. For the tekkies out there, Wikipedia tells you more (you can skip description this if you “get it” without the nasty details):
“Induction chargers typically use an induction coil [literally, a lot of wire wrapped like a spool of thread] to create an alternating electromagnetic field from within a charging base station, and a second induction coil in the portable device takes power from the electromagnetic field and converts it back into electric current to charge the battery. The two induction coils in proximity combine to form an electrical transformer. Greater distances between sender and receiver coils can be achieved when the inductive charging system uses resonant inductive coupling. Recent improvements to this resonant system include using a movable transmission coil i.e. mounted on an elevating platform or arm, and the use of other materials for the receiver coil made of silver plated copper or sometimes aluminum to minimize weight and decrease resistance due to the skin effect.” Whew! It works.
There are clear advantages: No cords. No electrodes exposed to the elements. No plugs to wear out. Great for medical implants (no surgery required as with replacing old-world batteries). And some big negative issues: “[L]ower efficiency and increased resistive heating in comparison to direct contact. Implementations using lower frequencies or older drive technologies charge more slowly and generate heat within most portable electronics.” (Wikipedia). Slow. Expensive.
But the negatives simply represent challenges to engineers in trying to figure out how to replace fossil fuels as our principal power source. If you can avoid fossil fuels and generate electricity from solar, wind, geothermal, hydroelectric and other green tech… and perhaps make fission and fusion nuclear power safer… the question then becomes how to transfer that electrical power to one of the biggest fossil fuel consuming technologies: cars and trucks. Currently, if you have a plug-in electric, you generally have a rather significant issue with “range.” You cannot drive from Los Angeles to San Francisco today with any commercially-available all-electric vehicle without a major stop for recharging.
A quick battery swap-out is one answer, but how would you field replacing a major section of your car with large part about which you know nothing? How about just a faster recharge? Tesla has created the most efficient mass-charging system for its vehicles – called a “Supercharger” – which can add 170 miles of range in thirty minutes. Kind of makes a long road trip a lot longer, not to mention that there are only about 500 venues that even offer this capacity in the U.S. Compare that to the five minutes it takes to refuel for another 300-400 miles at a traditional gasoline or diesel pump, with stations everywhere.
How about charging while you’re driving? Can we increase efficiencies to make this work? “Newer approaches reduce transfer losses through the use of ultra thin coils, higher frequencies, and optimized drive electronics. This results in more efficient and compact chargers and receivers, facilitating their integration into mobile devices or batteries with minimal changes required. These technologies provide charging times comparable to wired approaches, and they are rapidly finding their way into mobile devices…For example, the Magne Charge vehicle recharger system [developed by Hughes Electronics] employs high-frequency induction to deliver high power at an efficiency of 86% (6.6 kW power delivery from a 7.68 kW power draw).” Wikipedia.
Could we actually use the highway we’re driving on as the power transfer source? “The U.K., through a group called Highways England, is about to begin trials on electric highways which will see inductive charging equipment fitted underneath roads. When electric cars drive on them, their batteries would be juiced up as they drove by wireless technology running under the asphalt.
“Transport Minister Andrew Jones says the U.K. government is committing around $780 million over the next five years to develop rechargeable low-emission vehicles, aiming to ‘keep Britain at the forefront of this technology.’ As part of this overall initiative, the off-road trials will start later this year, and last for 18 months, while the government figures out the cost and feasibility of bringing it to the nation's highways.
“So it'll be a while before Brits can drive their Teslas indefinitely down the M25 without stopping for ‘gas.’ But the U.K. is not the first country to look into smart highways. A similar project in the Netherlands imagined a Smart Highway that could charge electric cars as they drove. This is clearly a path more than one country is considering pursuing.” FastCompany.com, August 13th.
But both the U.K. and the Netherlands are relatively small land masses with fairly contained highway systems when compared to the vast open spaces that define so much of the United States. Will this happen in the U.S. faster than driverless cars? Simultaneously? Or, given our current infrastructure track record, not at all.
While we have the technology to pass these charging costs (power as well as infrastructure) to those who use the system, it’s reasonably clear that it will take decades to get enough electric cars on the roads economically to justify the implementation of this capacity. But these front-loaded costs are a huge political challenge as we have seen from the current Congress; the one spending vector they seem unwilling to address is preparing for the future, at least as to non-military needs. Bottom line: we really need to adapt, prepare and grow! Now, or do we even have a viable and competitive future?
I’m Peter Dekom, and I agree with this question asked by FastCompany.com: “Wouldn't it be nice if America, which has been letting its own infrastructure crumble for decades, tried something similar?”