Automakers Race to Design Car-to-Grid Communications

By · September 03, 2009

“We all have to abide by the same laws of physics. When forced to do that, and do it in an economically responsible manner, you find out pretty quickly who is just talking and who has serious proposals out there.”

Greg Frenette
Ford manager of battery electric vehicle applications

Ford is scheduled to introduce the all-electric Ford Focus in 2011 and the Ford Escape Plug-in Hybrid in 2012—but the system to control how and when the car is charged is still early in development. “The clock is ticking,” Greg Frenette, Ford manager of battery electric vehicle applications, told “We have data to generate, information to absorb, and decisions to make.”

In August, Ford announced the introduction of an “intelligent” system for drivers to manage the charging of electric and plug-in hybrid cars. That system has been installed in exactly one vehicle so far—one of the 20 Ford Escape Plug-in Hybrids demo vehicles under evaluation at a handful of utility companies around the country. The wireless ZigBee-based communication capability will be added to the remaining 20 Escape plug-in hybrids by the end of this year.

Ford Intelligent Charging Interface

The prototype interface for Ford's on-board charging controls.

The system allows plug-in vehicles to exchange information back and forth with a smart meter. Frenette and his team of engineers have the tricky task of anticipating the rollout of smart meters—just 5 percent of today’s installed meters are “smart”—and trying to design car-to-grid communications before the industry has developed standards. In an interview with (see below), Frenette ruled out the possibility of rapid charging or battery swapping.

Short clips from videos, produced by Volvo and Nissan, to describe future wireless communications between plug-in cars and the electric grid.

Frenette does not see the communications systems as a competitive advantage for Ford, but rather as basic functionality that all electric car producers must offer. And they are all under time pressure. Nissan, which will debut the all-electric Nissan Leaf in late 2010, and Volvo, which is planning a plug-in hybrid V70 wagon, are among the companies beginning to paint a picture of the coming charging communications landscape.

Greg Frenette: Plug-in Communications, Battery Swapping, Rapid Charging How does the system benefit the driver?

Greg Frenette: On the navigation screen, the driver can tell the vehicle, for example, that even though the vehicle is plugged in and it’s 5 pm—I don’t want to pay the kind of electric rates that are prevalent at that time. Don’t accept the juice until the rates are lower, or I need to have a full charge by 6 am tomorrow morning. It’s all menu driven. There’s going to be that level of control and communication between the vehicle and the meter that gives consumers some options.

Will the production version of the system be wireless?

I’m not ready to declare that the wireless communication is the way to go. We’re very early on the pilot for these 20 vehicles. We’re working with the utility to study how robust, how reliable, and how durable that wireless interconnectivity is.

Will you be able to monitor the battery state of charge from the road, and perhaps inform consumers of nearby charging stations?

That’s a capability under serious consideration. With satellite communications, and navigation and so forth, our ability to process that information on the vehicle and acquire signals, and to convey information to the driver, is expanding at an exponential rate. The challenge to anybody putting an electric car into the market is how to best reduce range anxiety, and what technology can you bring to bear.

Are you considering an iPhone app to inform the driver while away from the car?

I can’t talk about our exact feature set, but as a technologist, I see that capability as very real and something you would expect to see in short order.

Can’t we circumvent all the worries about charging with battery swapping?

Quite frankly, I have not seen a viable high-volume approach that makes sense to me, either economically or technically. When you think about battery replacement stations, when you think about the volume of traffic in and out of the station, the number of battery packs that would need to be in inventory, and the energy necessary to keep them charged and in a certain condition, when you look at the implications of battery pack design on vehicle architecture and the demands to commonize that on competitive vehicles, I have some questions on how that occurs. It’s not clear to me.

And what about rapid so-called Level 3 charging?

You can’t just charge batteries at any level without some sort of impact on safety, battery life, reliability and durability. I’m not one that believes there’s a viable solution— given where battery chemistries and technologies are today—that says you can charge these batteries in two or three minutes and send them on their way. We all have to abide by the same laws of physics. When forced to do that, and do it in an economically responsible manner, you find out pretty quickly who is just talking and who has serious proposals out there.

You’re system relies on smart meters, and yet very few have been deployed

That’s today, but if you start projecting out over the next 10 years, those numbers are going to become significant. That fundamental metering technology is in place. The question is how can vehicles interface with that technology. What communications protocols need to be in place? What hardware and software do you need to start working on today, so that you’re ready when you introduce these vehicles two, three, four years from now. How do you design the interconnectivity so it’s intelligent and gives consumers a benefit?

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