EV batteries won't have to exactly reach the range and energy density of a tank of gas, but they'll have to meet a few pretty hard requirements to be successful.
A good analogy might be the smart phone. Before smart phones, we might expect a week out of a single phone charge. With a smart phone, we have to live with charging every day. However, the increase in functionality made the trade off worthwhile (mostly).
An electric car will need to do a similar thing. It has to have a big enough benefit - something that liquid fuel cars don't have - to make the trade offs worthwhile. I don't see that on the horizon any time soon.
a 200 mile range is good for a commuter car. That's enough range to be able to make a daily 50 mile (total) commute without fear of running our of battery power. It's not realistic, however, in my opinion, for anything other than around town use.
Some of the promising new anode materials like silicon nanowires could make this an achievable goal by providing 4-5x the charge storage in the same battery volume.
The biggest challenge is not range, but charging time. Those future batteries with 4-5x the capacity will also require 4-5x the charging current to charge in the same amount of time as today's batteries -- and that charging time is already too long for EV purposes.
You've got a good point. I'd agree that the biggest challenge is charging time, but range certainly ranks up there. Fast charging would offset some of the problems with limited range, but at some point, range becomes too short to be practical. That's where thos 4-5X batteries will come in handy - if we can shove that many electrons around fast enough.
I may be off topic a bit here, but the bit in the article about the national media got me thinking about the EV radio commercials I've been hearing. What no one seems to be addressing is where the electricity will come from? Aren't we just trading one problem for another here? Feel free to set me straight...
Depends on where you live. Hydro and wind are more than capable of supplying energy for many areas. Unfortunately, we don't have great ways to transport that power to areas that don't have access (from what I'm told).
Yes, it depends where you live. EETimes had a story not long ago -- with a link to an article in another publication -- about the equivalent mpg of EVs in each of the 50 states, which varied depending upon the means by which electricity was generated in those states. Some with lots of hydo & nuclear power, like Vermont, had huge numbers, upwards of 2000 mpg. Others, where coal was more dominant, had much smaller numbers.
The point has also been made about the inadequacies about the transmission infrastructure. I remember reading that during the big east coast heat wave this summer, a wind energy farm in the northeast was directed to turn down its output -- at a time when electricity demand was the highest -- because the transmission infrastructure couldn't handle it.
Still, there are those who have successfully argued, with supporting data, that even with today's electricity generation methods & aging distribution infrastructure, that EVs are still more efficient than gasoline combustion engine vehicles.
@Janine, (and Frank, thanks for recalling the article I posted a fe weeks ago), here is some data provided by Climate Central:
"EVs Are Environmentally Friendly?: True or False?"
@JanineLove: to a large extent, you are correct, we are mostly trading one problem for another. A truly renewable source of energy (Solar & Wind for now) when used to charge EV's can further enhance the green-ness of EVs. But there is also a large component of materials used in the operation of EV's are not efficiently recovered (like Li Ion batteries) so the problem compounds.
I had exact the same question as you do. What worse is, recent study suggested, manufacturing an EV may consume a bigger carbon footprint than running a gasoline operated vehicle because of material of choice. Nonetheless, solar, wind and hydro will no doubt become the energy of the future for various reasons. EV will certainly be the only choice. Now, we may argue EV may not be as friendly as regular vehicle. Without you knowing, EV may be the only choice in the near future.
When batteries with 4 to 5 times the energy-density of present day batteries arrive this would imply a Tesla Model S would have a range of over 1000 miles. Except for those people with no possibility of charging overnight, would charging time be an issue since very few of us could manage to drive over a 1000 miles in the course of a day.
As for charging times themselves, a lot of R&D has gone into silicon anodes and I have read some papers that claim charging rates as high as 20C with exceptional energy density and over 5000 charging cycles before a 20% drop in charge capacity is reached.
The issue is can these anodes be mass manufactured at a competitive price?
"When batteries with 4 to 5 times the energy-density of present day batteries ..."
The problem is, this has always been the case with batteries. That "when" has not yet arrived, after more than 100 years. So other approaches should be mentioned more in the popular press, to make people aware that energy storage in a battery is not the only EV option.
Not to mention, something that keeps being overlooked, installing additional electric transmission lines is not so easy to do. Any battery storage requires upgrades to the grid, if BEVs are going to make it big time, to replace what we have now. People don't want power lines in their back yard. Powering the automotive, mass transit, and industrial fleets with batteries does increase demand appreciably, as we've discussed here before. It's hardly insignificant. And installing windmills in your backyard, and/or enough solar panels to take the load, doesn't work out too well either. So that's why in practice, especially if these BEVs will be running and will be recharged throughout the day, you do need more electrical transmission lines installed.
Bert said: The problem is, this has always been the case with batteries. That "when" has not yet arrived, after more than 100 years.
My opinion is that this is mostly because most people stopped working on improving battery technology 100 years ago. Few advances happen by themselves -- people have to be looking at the problem, or at related problems so they notice anomalies that are key to many discoveries.
In the last 100 years scientific technology has come a long way. For example, with the Scanning Tunneling Microscope you can examine surfaces at the atomic level, something inconceivable 100 years ago. Once you have people wondering "why can't we get higher energy density?" you'll see plenty of progress with tools to analyze what's really going on. Look how far Tesla Motors has come in just 10 years.
"It's not just technical challenges that's holding back electric cars."
True, but perhaps you misunderstood where I'm coming from. What is holding back EVs is technical challenges, in large part, and the incessant assumption that energy storage must come from a battery.
We know the HEV pretty well by now, where H means "an internal combustion engine." That's somewhat unexciting, in my view, but is definitely doable and has no energy starvation issues. Problem is, there's still a Carnot engine in the equation.
Much more exciting are HEV designs without the heat engine, and my hopes continue to be in the fuel cell car where the hydrogen is produced on board, rather than distributed and stored as H2 gas.
I like the idea of a fuel cell as a range extender -- renting one could be a dandy way to extend a battery or other high-power electrical energy source for long trips.
HEV with an ICE is an ugly solution, since the car has to lug around a heavy ICE whether you're using it or not, you have to run it periodically so the gasoline and other fluids don't get old, and you still have all the maintenance and emissions issues of an ICE car. A Tesla is so marvelously simple, and so reliable that car mechanics are worried about their future livelihoods. IMO, a Chevy Volt far more complex than anything I'd want to own.
BEV is not the only option but it is the most practical. IMHO, fuel cells are about 10 years too late. Hydrogen infrastructure is simply too expensive to build out and on-board hydrogen reformers will in all likelihood become too expensive as the US exports its natural gas and imports a significantly higher world price.
As for grid improvements, that can be done incrementally as BEV market penetration increases. A lot of this infrastructure is ageing and needs replacement or upgrading in any event. Additionally the vast majority of BEV charging occurs overnight when electricity demands are low at least for now.
I wouldn't dismiss solar so quickly as solar LCOE will hit $.08 per kWh in a few years. This converts to $2.70 an e-gallon which beats DoE target goals for hydrogen of $4.00 a gallon. Furthermore the story is not over for solar. Swanson's Law will continue to drive LCOE prices ever lower. If any of these very high efficiency panels ever come to the marketplace, one expect solar LCOE to approach a penny a kWh in due course!
Finally, BEVs are more efficient then FCEVs. I would much rather drive a fuel miser(BEV) at $2.70 a gallon then a fuel hog(FCEV) at $4.00 a gallon.
As GM and Ford not producing gasoline, EV batteries should be made by battery manufacturers with open interface, mounting styles and charging standard. They will push battery evolution much better than the effort from each individual EV maker.
One standardization example is the EV charging interface, by nature the interface should be DC and leave the AC capacity and PFC issues to outside commercial/home charging station.
Another standardization example is the battery safety. We know Li-ion battery could explode under impact. A bottom mounted style (such as in Tesla) should not be allowed, because an explosion by bottom impact could cause casualty for people in car. The bottom impact is rare, but very possible when a car run off the road.
It's no accident that automakers are looking beyond the knee-jerk battery storage solution, for EVs. I agree that EVEN IF the range is extended to where the hype says, which if it holds true at all, it's only under the most ideal conditions of 73 degree F days, level roads, and light breezes, the time to recharge is a still a big obstacle.
We need to get some press coverage of more credible alternatives, so people can move beyond just the battery-electric solution.
Maybe my transportation needs are different from most peoples but I sitll think that what we really need is not an affordable (whatever that means) long range EV, but an affordable (in just as cheap as the gasoline equivalent) shorter range EV.
There are many people out there who simply don't need a 200 mile range vehicle. To me the solution is to make it lighter weight and cheaper primarily by making the battery smaller. We can argue about optimim range for a "city car", but 75 miles would be plenty for many people - IF car companies could make it just a cheap as the typical small gas powererd car it would compete with I think you would see a market for them.
Having a low cost, low maintenance vehicle that never has to go to a gas station would appeal to many. And people will pay for convenience. For people in urban areas their commute to a gas station can be farther than their commute to work. Gas stations are starting to disappear from many urban areas because of the high costs of real estate. In some places now finding a gas station and waiting for your turn in line and then getting out and pumping smelly gasoline (sometimes in inclement weather) is becoming a major hurdle - especially during rush hour when many people decide it's time for them to refuel. The ability to just drive home and plug in your car (maybe in a nice warm garage) would be much more convenient.
The range requirements will be highly variable from one person to another, depending on where you live, where you work, where you travel for shopping and recreation, and availability & convenience of public transportation. Consider the differences between the U.S. east coast and the western states. Distances between the places of interest in one's daily life tend to be much shorter on the east coast, public transportation is fairly extensive and "the middle of nowhere" is a faraway place you might go for a weekend getaway. But a resident of a western state, even one who works in an urban center, may have a very long commute between home & work, with limited public transportation options until he is near the city, and "the middle of nowhere" might be more a part of his regular routine -- and a place he really doesn't want to get stranded by a dead battery.
On a side note, is subsidizing EVs and Hybrids really the right way to drive adoption of this technology? Only the rich can afford to buy these expensive cars (even after the tax break) which results in the middle class effectively paying for the jet-set to show off their green credentials. The market should decide which technology succeeds - and EVs will hopefully work out on their own merits.
What are the engineering and design challenges in creating successful IoT devices? These devices are usually small, resource-constrained electronics designed to sense, collect, send, and/or interpret data. Some of the devices need to be smart enough to act upon data in real time, 24/7. Specifically the guests will discuss sensors, security, and lessons from IoT deployments.