A number of interesting things have occurred at the AAAS meeting in San Jose the last few days, here is one that caught my eye. As many readers know, I have an electric car (seen above), which runs on 12 volt Lead-acid batteries which are so heavy that most of the energy to the motor is used to move that heavy mass of lead around. Electric cars don’t make a lot of sense for an all-around car, but for in-city use, such as errands or delivery, they could be quite viable with better battery technology.
This newer Lithium-sulfur batteries show promise beyond the current favorite lithium-ion batteries due to their energy density and lighter weight:
The current energy density of lead-acid batteries (not depicted on the chart) is around 60-100 Watt-hours per liter, well below all the others.
The lithium–sulphur battery (Li–S battery) is a rechargeable battery, notable for its high energy density.[1] By virtue of the low atomic weight of lithium and moderate weight of sulfur, Li–S batteries are relatively light; about the density of water. They were demonstrated on the longest and highest-altitude solar-powered airplane flight in August, 2008.
Lithium–sulfur batteries may succeed lithium-ion cells because of their higher energy density and reduced cost from the use of sulfur. Currently the best Li-S batteries offer energy densities on the order of 500 W·h/kg, significantly better than most lithium-ion batteries which are in the 150 to 200 range. Li-S batteries with up to 1,500 charge and discharge cycles have been demonstrated, yet are not commercially available (as of early 2014). (Wikipedia)
Let’s hope that they come to the market soon, not just for electric cars, but for many other applications that need high energy density and low weight.
Leading scholar presents advances in research of electric car batteries at AAAS
Lithium-sulphur batteries promise to extend the range of electric cars at least three times over current lithium ion cells and at much lower cost, making electric cars practical and potentially more appealing to a mass market. Linda Nazar, professor of chemistry from the Faculty of Science at the University of Waterloo, will present a perspective on the promise and reality of lithium-sulphur batteries at the American Association for the Advancement of Science (AAAS) Annual Meeting in San Jose, California. She will highlight recent innovations in nanomaterial strategies and new electrolytes that can help these future-generation energy storage systems realize their potential in emerging markets.
Professor Nazar and her research group are best known for reigniting interest in the lithium-sulphur battery by proving that such a battery, once considered impossible, could be a reality. Recently, her group resolved a major technical hurdle by developing the first high-performance sulphur cathode with the use of manganese dioxide nanosheets.
Nazar is Canada Research Chair in Solid State Energy Materials and a Fellow of the Royal Society of Canada. She is a member of BASF’s Research Network on Electrochemistry and Batteries, and serves as a lead scientist on the U.S. Department of Energy’s Joint Center for Energy Storage Research.
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New Materials and Approaches for Advanced Batteries (part of the Next-Generation Batteries for Mobile Devices and the Grid symposium
A battery swap system would be great, if it could be worked out. Large solar collection facilities in sunny locations “fill” lots of batteries, which are then transported to battery “gas stations.” Rather than recharge, the discharged battery pack would be swapped out for a fresh one. This would have to be doable in about 10 minutes or less, to make it the equivalent of filling up your tank now.
I wonder how far from that possibility we are?
You lose far less electricity when transmitting by line than if you were moving a load of batteries across the highway. Batteries are _heavy_. The only way it could work is to swap your used battery at the, er, “gas” station and then have that station recharge the battery for the next swap.
The hindrance to this is threefold:
1.) No gas stations currently have massive electrical hookups to the grid (and….would we want a huge electricity pipe to a gas station next to the, you know, gas? I’ve seen high currents cut right through metals as if they were butter, so a failing fat electrical pipe next to liquid fuel storage might be bad. Although I have no idea if gasoline and diesel could catch fire/explode from purely electrical input.)
2.) The speed of these recharges would still be fairly slow. Charge a battery too fast and it’ll explode. Even the Tesla superchargers need about an hour to fill from 0 to full. (it’s something around 175 miles per half hour of charging and the crappy battery does ~270 miles). If all of the current gas/diesel vehicles were magically made into EVs and likewise for gas stations to charging stations, you wouldn’t be able to handle the number of batteries that need swapping. You’d have far more batteries than you could charge. (and this is assuming that half of those gas->EV conversions charge exclusively at home)
3.) Toxic waste. Quite simply, batteries are TERRIBLE for the environment. They are noxious to make, carry use risks (fires and explosions), and don’t just biodegrade when the 1500 use-life is over with. Recycling their components is often too expensive compared to making more. Lead acid (the battery in your gas car) batteries are currently fully recyclable but they often are disposed of improperly. Same with car tires.
“Although I have no idea if gasoline and diesel could catch fire/explode from purely electrical input”
Gasoline and kerosene sure can. It has happened with aircraft.
Fluid gasoline and diesel are not flammable for being too rich to support combustion. They must be vaporized and carefully mixed with oxidant to ‘explode’. Hydrogen, now that is a different story, will explode from 2w/w to 96w/w.
JamesS
Assume 1,000 pounds of battery per car, and 100,000 cars (mid size city): You’re wanting to transport a hundred million pounds of batteries around in the name of saving energy?
Assume batteries yield 1 mile per 4 pounds of weight; gasoline yield 1 mile per 3oz @ur momisugly 40MPG. You’d be moving batteries equal to 21 times the weight of the equivalent gasoline.
That system was tried in Israel. Modified Renault cars if I remember correctly. The idea was good but I understand that they went bankrupt.
Iab
Yes.
Probably it was a Smashing Success with government funding and then, well, not so much when the sweet, sweet taxpayer money expired. Just like just about every other “sustainable” energy solution that exists due to government spending. I have to wonder how long taxpayer wallets are “sustainable”.
And the idea was good?
What’s the definition of bad?
Cutting through all the numbers, the most sensible electric solution today is a plug-in hybrid such as the Chevy Volt. Chevy claims 38 all-electric miles per charge which is sufficient for daily use for a large chunk of US automobile owners. Beyond all-electric miles it’s gasoline. No range limits. Instant gasoline refills. Long weekend and vacation trips. Does it pencil out in dollars and cents without a taxpayer rebate? Probably not. But cars are not a purely rational purchase in any case.
Chevrolet currently claims that Volts have driven almost 700 million EV miles out of a total of 1.1 billion miles driven.
http://www.chevrolet.com/volt-electric-car.html#how_volt_works
Batteries will get there someday but not tomorrow.
I would like to see the source for “38 all-electric miles per charge which is sufficient for daily use for a large chunk of US automobile owners.” Having been damn near everywhere, I can’t think of many places where it’s common to not have a decent commute. According to USA Today, the average commute is 25.5 minutes one-way. http://www.usatoday.com/story/news/nation/2013/03/05/americans-commutes-not-getting-longer/1963409/
If you assume that both the cars are only using electricity for driving (because stop-and-go will eat your battery to death if you are using any accessories) and 40 mph is the average speed, that means that the average American will just eek home each day under that 38 miles. No stopping for groceries, no hitting the bar, no meeting your brodawgs for ultimate frisbee, nothing.
According to the US-DOT, Federal Highway Administration, the Average Annual Miles per Driver is 13,476 which, based on a 365 day year, is 36.9 miles per day.
http://www.fhwa.dot.gov/ohim/onh00/bar8.htm
What counts as a “large chunk” is open to interpretation but the above numbers support the statement that “38 all-electric miles per charge [ … ] is sufficient for daily use for a large chunk of US automobile owners.”
People I spoken to who own and operate Chevy Volts use them daily for commuting and buy gas once every three to six weeks. I once had a 45 mile each way daily commute for which 38 miles would save only a little over a gallon a day. On the other hand, many people I know live and work in the same or nearby suburbs and would only need to visit a gas station to buy lottery tickets.
I stand by my statement.
I have never seen a Volt plugged in. My suspicion is the drivers bought them for the cool factor, or they work for Chevy dealerships.
Speed, 365 days a year? In other words you drive to work and back every single day of your life? That’s really, really abusive of raw numbers (or sad, depending on if that’s an accurate representation of someone’s life.) Sorry, but the reality is that they drive back and forth to work for 250 days a year (5x50weeks) and the rest of the time they either go nowhere or take long trips (e.g. traveling to see family on thanksgiving or Christmas).
Sorry, but even with this additional information, I cannot buy into your assertion, especially after I just linked to average one-way commute times. And getting into the “Gas savings” of the Volt expands on your original statement that was exclusively focused on the battery life, especially when your secondary backup statement is “many people I know.”
Well, “many people I know” travel more than 30 miles each way. 🙂
Speed,
You calculations of average driving miles per day suffer from same problem as earth’s global temperature – it is not very useful in real life.
Why? Because you don’t commute to work on weekends. So, you have to drive over 50 miles for 5 days and then you drive very little for 2 other days – or your household uses only 1 car instead of 2.
And more than half of the population will not be able to commute to work on 38 mile charge.
Are you trying to get us to believe that Chevy Volts have done 64% of ALL miles driven on the roads. (that’s 7/11 in case you want to check) ??
Scientists should forget their obsession with energy density. Existing Li ion batteries such as used in the Tesla are fine and give 300 miles range which is more than adequate for urban use. The problem is, and always will be, battery COST per unit of energy stored.
Having run a major international advanced battery programme for electric vehicles and power storage in the late seventies and early eighties (private sector funded!), I have a particular interest in developments such as described in this article. Virtually no progress has been made in improving the cost metric.The new Tesla ‘mega factory’ will reduce manufacturing cost, but it will still be far too high to challenge I.C. vehicles in the mass market.
Because of this, widespread use of E.V.’s is a pipe dream, as is battery storage for load balancing of ‘renewable’ energy sources.
So in other words due to economics, pure electric cars are for those who like novelty items or for the top 5% earners who like to pretend they are green, while owning 5,000 square foot homes and multiple non-electric autos and or planes.
Exactly so!
I’m not a top 5%’er. The cost of running an equivalent fuelled car in the UK for a decade is the same price as the car.
Therefore my EV over a decade (75,000 miles) is effectively free!
Old’un
February 15, 2015 at 8:18 am
“Scientists should forget their obsession with energy density.”
No, it’s critical. Depending on energy density you reach an asymptote where adding more storage does not increase the range. That’s why all current “affordable” small EV’s hover at the 100km range limit, while the comparable gasoline car has a typical 600km.
David Mackay computed it in “Without Hot Air”, you find that book online.
Well I bet if you did some digging, you might find that the “cost” of that electric vehicle is somehow related to the energy density of that lousy battery.
If you could increase the energy density of the battery by a factor of ten, you could use a much smaller battery and a lighter car, and that would cost much less.
It is NOT a cost problem; it is and always has been a technology problem.
A practical technology for electric cars does not exist. If it did, then you wouldn’t be able to keep people away from them, and they would be affordable.
But so long as you treat it as an economics problem, you will put economists to work on solving it. You need to put scientists and engineers to work on the technology problems or they will never be solved.
It has always been that way with alternative energies or resources, and it always will be.
Economic problems are solvable with a pen. You just decree the solution; that’s what Obama does.
Do the LI-S batteries have the same property of exploding when mishandled that their Li-Ion cousins have?
That could be a large hurdle to overcome when considering it for highway applications.
Somehow we overcame, or ignored, that hurdle with very explosive gasoline.
Charlie
Gasoline is certainly flammable, but only very infrequently explosive (i.e. in Hollwood or on Myth Busters).
Your statement implies society has a long history of actively ignoring wide-spread legions of exploding cars – something that all of us know from our daily lives is simply not true.
Good grief.
Have you read USAF rules for air transporting Li Ion batteries? They don’t quite require one man continuously guarding each individual battery with an extinguisher.
Gasoline of any kind is not explosive, but it still is highly flammable. An explosion requires very particular conditons, like a propane/air bomb. Witness the recent car train crash in New York. Befuddled driver for sure, but that kind of fire is hardly less of a problem than an explosion. A couple years ago a semi tanker carrying gasoline rolled over on an off ramp in Harrisburg, PA. The ensuing fire stopped traffic for a day on the main highway and they had to replace a $100M overpass, which took close to a year.
Any kind of high density power supply can cause massive problems. Horses never exploded or caught fire, but they had other problems.
Lithium Ion rechargeable CELLS such as AA size for example, are simply not available for sale in the USA, although they may be used in computer or laptop batteries.
You can buy Lithium Ion BATTERIES but not lithium Ion CELLS. That is because the batteries must carry inside a current limiting and over-temperature protective circuit.
So you can get Ni-MH rechargeable AA cells, I have dozens and AAAs as well for my cameras and flashes, but you can’t get Li-Ion cells.
Li-Ion cells can not be carried or shipped aboard any commercial airliner, but you can carry your laptop battery.
UPS and Fed-Ex have special rules for shipment of Li-Ion cells (to battery assemblers.
So Tesla is not alone in having a big battery headache.
That’s what I thought. I know little about LiS cells but I had a notion that they were favourite for model helicopters because they have a good power to weight ratio, but they could ignite, almost spontaneously.
No, current model cells are lithium polymer ion: not lithium sulfur.
And also lithium iron phosphate. Heavier but tougher.
…Electric cars don’t make a lot of sense for an all-around car, but for in-city use, such as errands or delivery, they could be quite viable with better battery technology….
Could be? They have been used that way for around 100 years. See http://en.wikipedia.org/wiki/History_of_the_electric_vehicle
And a lot cleaner than the unleaded fuel on short distances.
“Unleaded petrol is a different kettle of fish and is much more dangerous
as I will proceed to prove. More than half of a litre of unleaded is not
petrol. It is actually a brew of aromatics and if witches had brewed this
cauldron, it could not be more evil. The aromatics that replace lead are
Dimethybenzene, Mesitylene, Toluene, Xylene and Benzene.
All of them are declared carcinogens and will cause leukaemia and other
cancer related illnesses. Note that I have said will not might. I will
quote from one authority, Dr Warren, who was the adviser to the
Government at the time and warned against unleaded and was ignored:
“In fact this stuff appears to be so dangerous, potentially lethal, that
I urge you not to use it in any car not fitted with a catalytic converter.
Don’t use it in your mower, chainsaw, whipper snipper, or outboard
motor and don’t wash parts in it and if it gets on your skin, wash it off
immediately. Avoid fumes when refueling and don’t allow anyone near the
exhaust, particularly when the exhaust system is cold. Remember that
catalytic converters don’t work until they reach some 400 degrees .”
http://www.benzworld.org/forums/g-class/178884-interesting-article-leaded-vs-unleaded-fuel.html
That is an eye opener.
I’ve worked with all of those. As long as you don’t drink it you’ll be OK.
I’d be cautious about the “claims”, sounds a bit like someone with an axe to grind.
https://books.google.com/books?id=n9K6-CUHz-kC&pg=PP8&lpg=PP8&dq=leaded+gas+vs+unleaded+gas+aromatics&source=bl&ots=i3Bw8P3GX-&sig=rGNGQT8QIRpL56xT9Ox9UWOu764&hl=en&sa=X&ei=ZDPmVIjhLJCZyQT0joL4Dg&ved=0CEIQ6AEwBg#v=onepage&q=leaded%20gas%20vs%20unleaded%20gas%20aromatics&f=false
If it’s for CO2, then don’t do it. if it’s for better transportation, then I won’t have to pay for it and, by all means, do it. If you have to hurt or derive your success by hurting an alternative, it is not better. If it’s about being futuristic, pay for your own vanity and remind yourself that electric cars are really, really old school for several reasons.
This past week I made two trips from my home in Maine, one to Quebec City, 585 miles round trip and to Sugarloaf Mountain, 250 miles round trip. My Volvo XC 70 started at minus 15 F with no problems. It handled snowy roads with the lights on and we were comfortably warm. We were also in a vehicle in which we could survive a collision with a moose. We were able to purchase gas in remote small towns in Northern Maine, but I didn’t see any signs advertising charging stations. Don’t look for many folsk in this region to be buying electric cars.
With higher energy density comes higher explosion risk. It remains to be seen if these batteries can be made crash safe. The metal-oxygen type batteries are a lot safer, because they don’t have instant access to all of the energy.
I’d be interested in seeing actual data on battery lifetime vs. ambient temperatures. How well do batteries survive in Phoenix with summer temps hovering +40 degC and in Yellowknife, NWT with winter temps hovering -40 degC? My own experience with golf cart and road vehicle lead acid batteries in Saudi Arabia is not good.
You normally want to shutdown charge to Li-Ion at about 50 degC and discharge at around 60.
You really do not want them to go over 70 as they can enter thermal runaway state, with explosion resulting (the industry uses “venting” as a safe term for that particular event)
Interchangeable batteries. Sort of like those propane tanks you get for your outdoor BBQ available at Wallgreens and a lot other places these days. A simple means to slide them in and out is all that’s needed
Steve
If given a choice between a “ruptured tank” propane automobile accident and a “ruptured tank” gasoline automobile accident, pick the gasoline car…words to live by.
Not only that, gasoline tanks can be filled with a foam to prevent spillage from a rupture.
The propane tank wouldn’t necessarily have to rupture to cause troubles in an accident. If the fuel line is compromised, then there is an instant burst of liquid propane to be concerned about. The tanks are fairly strong. I converted a rotary motor Mazda p/u to propane trying to meet smog requirements. It ran fairly well, but there was a power loss. The fuel mileage dropped as a result. I had to always be on top of how much fuel I had, and where the closest propane station might be. I started carrying a 7 gallon tank as a reserve. It sat next to me on the floor of the passenger side. It was somewhat reassuring to know that in case of a bad accident, at least I wouldn’t burn to death.
There are two ends of the scales to consider. The IC engine at one end and the electric motor at the other. Both have their advantages and disadvantages and the ONLY way to approach this is to try to eliminate the problems in BOTH. The answer is, therefore, HYBRID technology.
Hybrid vehicles have already proven their worth in efficiency so to promote either an entirely-gasoline or an entirely-electric vehicle is wrong and only the reserve of the relevant proponents.
The answer ?!?!
What was the question???
A Honda Accord Hybrid costs $7,500 more than a Honda Accord. That crushes any advantages gained from adding hybrid technology. Or even HYBRID technology.
Gamecock,
Good answer,
Another answer: let the market decide not the government or the misleading media. People have answered and low electric car sales are their answer, they are much smarter than Washington.
I have two gasoline powered cars and don’t see any disadvantage, in fact a huge advantage when the American free market system is allowed to discover and bring fossil fuels to market at $2.00/gal.
I have been without electricity for 1 week periods several times in the last two years and would not consider a car that needs electricity from my house unless I also invest in a generator.
At least I could get to the store for food or a hotel if necessary not being totally dependent on electricity. BTW I also have a gas stove in the kitchen for cooking, gas hot water heater for bathing and would not want it any other way.
I’d recommend a large grain of salt. I seriously investigated LiFePo4 batteries several years back because they appear to offer cost/performance savings over lithium ion. The savings exists, but so do all sorts of problems with the LiFePo4 such as nonstandard decline. Or in other words, otherwise identical batteries in the same batch, in the same circuit would decline at different rates – which in turn completely hoses the electrical system.
Energy density is thus in no way an adequate means to evaluate the utility of any given battery technology. Cost, reliablity, number of cycles, etc all matter.
I have a LiFePO4 battery in my Honda motorcycle for about 2 years now. Ballistic and Shorai both sell drop-in replacements for the Pb-acid batteries from the manufacturer. Unlike Li polymer, LiFePO4 batteries use the same charging circuit as factory stock. Better cold performance and less self-discharge in addition to lighter weight are all improved.
These Lithium-sulfur batteries have arrived just in time to start consuming the sulfur mountain caused by the legal demands for ‘low sulfur’ diesel!
I for one think this is all very exciting. Anyone who thinks electric cars have no future isn’t looking at the level of commitment by governments around the world. An example being the agreement signed in the UK recently by the government and opposition. Almost unheard of before…..
http://www.theguardian.com/environment/2015/feb/14/cameron-clegg-and-miliband-sign-joint-climate-pledge
More and more money will be invested in reducing our dependence on oil and coal. It doesn’t matter whether you or I like it…. it is the future.
Electric cars will have a future when they’re self-driving, and can go off to a central charging station when they’re not in use. Especially, when they’re owned and operated by an Uber-type service.
Just click the bugger in when you get home. Done!
Just because the three indistinguishable parties in the UK sign a suicide pact, doesn’t mean much. And where is that ‘more and more money’ going to come from, when the British government has already doubled its debt in the last few years? The country is bankrupt, and increasing the cost of energy will only make the economy collapse faster.
Electric cars had a great future a hundred and fifty years ago, until someone invented the internal combustion engine and they became obsolete overnight. It’s taken us that long to remember why they sucked.
Now, I’d agree that, in the far future, they’ll probably be the norm: no-one’s going to be driving a gasoline-powered car on Mars or the Moon any time soon, and you won’t want to drive them in a sealed habitat of any kind in free space. But I can’t see they have any future on Earth, unless you can install nuclear power sources that only need replacing every couple of years.
No new power sources required. Fuel takes 6.5KWH per gallon just to crack and refine it from crude.
And if the fuel produces 33 kwh after it’s refined, where do we get the other 26.5 kwh?
Where did Cameron, Clegg and Miliband get their engineering degrees?
Hey – Miliband has ‘A’ Level Physics!
I’m not sure the others could recognise a simple lever.
Still – they’re following the Green Blob, although it does look – to an outsider – as if they’re taking Brezhnev’s money after all these years. They’re not, ‘cos that was old, useless roubles [contrast with Generalissimo Putin’s new useless roubles]. But it looks that way.
Auto
Simon
So how long do you think this uneconomical government-subsidized scheme will run on other people’s money?
As long as you keep voting them in.
I don’t understand, where does the electricity com from, if not coal or gas it will double in price as promised by the President.
Investing money to replace oil/coal has been a bust so far for the average guy given the wast of tax dollars with negative results. That’s exciting?
A point that should be considered in all of this, is that they always talk of charging cost of 0.10$/kwh. Here in California there is a 3 tiered rate system which is now around 11 to 12 cents for baseline usage. I have never been able to stay within the baseline even though I was a minimal user, careful about turning off lights, no air conditioner, and so on. Despite that, my electric bill always had a portion of 3rd tier billing which was triple the baseline rate. If I were to purchase an electric vehicle, then I would have to pay triple, around 38 cents per kwh to charge the vehicle.
<blockquote By virtue of the low atomic weight of lithium and moderate weight of sulfur, Li–S batteries are relatively light; about the density of water.
I do not fully understand the meaning of this quote nor its pertinence. Lithium and sulfur are respectively of higher atomic mass than hydrogen and oxygen. Actually the ideal battery would be lithium-air because the air wouldn’t have to be stored on-board. And better still would be replaceable packs of lithium which would allow instant refueling and lightweight for convenience. Even replaceable packs of current Li-ion batteries are somewhat bulky and heavy. The technical and materials problems are still quite daunting, however.
I teach senior capstone design in an engineering college. We participate in the SAE Baja competitions year and decided a few years ago to build an all electric version as a separate project. Why our original sponsor decided to start with lead acid cells I do not know, but the vehicle was fun for about 15 minutes and weighed in at twice the gasoline SAE vehicle. Year by year we improve the vehicle and this year we are switching to lithium ion batteries, in hopes of extending the fun to 45 minutes or so; plus using swappable cell banks for fast refueling. They are still surprisingly bulky and heavy.
The recent Paris-Dakar rally included an electic powered racer. The entire set of battery packs had to be replaced every ~300km or so. I don’t have any more detail than that sadly.
Mod. I fouled the block quote in my previous post. Is it repairable?
When cell phones first came out they were big and clunky. When they got smaller they included replaceable batteries so that the owner could carry a spare and never run out of juice.
Now … we’ve pretty well put all those problems to bed. And so will it be for electric and/or hydrogen powered cars.
Hint: the power requirements of cars are set by the laws of physics, while those of cell phones are set by the laws of technology. You need a certain amount of power to push a car-shaped object along the road at 60mph, and that power requirement doesn’t obey Moore’s Law.
And, even today, poor reception that requires the phone to boost its transmit power will suck the battery dry in a day or less.
MarkG wrote, “Hint: the power requirements of cars are set by the laws of physics … ”
Perhaps you meant “energy requirements” as in, “Regenerative braking reduced the amount of energy required to drive from home to the grocery store.” Or, “Increases in battery energy density, specific energy and reduction in charging time will make electric cars more practical.”
Try 2 or three hours with poor reception and -10 C temperatures. I carry TWO portable battery packs when I go skiing. I shut the phone off in the back country as the phone gets so hot searching for service you can hardly touch it.
Speed
Umm…no, I think Mark meant “power” not simply “energy”.
Try driving your car (any car) at 70MPH with “regenerative braking” or “good karma”, whatever. Energy is simply the ability to do work; power is how fast (e.g. 70MPH) you do work. Energy and power are related but not interchangeable.
No, I meant power, which is why I said power. Regenerative braking is irrelevant when you’re driving at 60mph on the highway, since… you’re not braking. Nor, as I’ve pointed out before, does it make much difference on a gasoline car, since most already shut down the fuel injectors while you’re braking. Regenerative braking just means the engine has to burn more fuel, either keeping the engine running while you brake, or keeping it idling for longer if you brake faster. Taking your foot off the gas and letting the engine slow you down you probably saves more fuel.
Yes, you can make a car more aerodynamic, but you can’t half the power usage that way and still have a car that many people want to drive; and you certainly can’t do that every couple of years, as you can with CPUs. Most of the fuel consumption improvements of recent years have come from reducing power wasted in the engine and transmission, not reducing the amount required to keep the car moving.
MarkG wrote, ” You need a certain amount of power to push a car-shaped object along the road at 60mph, and that power requirement doesn’t obey Moore’s Law.”
But you need a certain amount of energy to get your 60mph car the 274 miles from St. Louis to Chicago.
MarkG also wrote, “Regenerative braking is irrelevant when you’re driving at 60mph on the highway, since… you’re not braking.” Correct.
MarkG continued writing, ” … most [gasoline cars] already shut down the fuel injectors while you’re braking. Regenerative braking just means the engine has to burn more fuel, either keeping the engine running while you brake, or keeping it idling for longer if you brake faster. Taking your foot off the gas and letting the engine slow you down you probably saves more fuel.” Wrong. Gasoline engines shut the fuel off when coasting (foot off the gas) in gear whether or not the brakes are applied. Some go further and stop the engine while the car is stopped. Regenerative braking substitutes generator drag for brake friction in order to add energy to the battery which is then used in lieu of some or all of the gasoline energy when accelerating from the stop.
Give it up. Hybrid cars use less (external, ie. gasoline, diesel or grid supplied) energy than non-hybrids. Much less in stop-and-go and a little less (because they have smaller, more efficient engines) at constant highway speeds.
“But you need a certain amount of energy to get your 60mph car the 274 miles from St. Louis to Chicago.”
Yes, and? What exactly is your argument here?
“Wrong. Gasoline engines shut the fuel off when coasting (foot off the gas) in gear whether or not the brakes are applied. Some go further and stop the engine while the car is stopped. Regenerative braking substitutes generator drag for brake friction in order to add energy to the battery which is then used in lieu of some or all of the gasoline energy when accelerating from the stop.”
Sigh.
If you let the car coast to a stop, it doesn’t burn any fuel in the process. If you use brakes, it still doesn’t burn any fuel, but you’ll spend more time idling because you’ll stop faster. If you use regenerative braking, you’ll recover some of the energy that would otherwise have been wasted heating the brakes, but you’ll still burn more gas than you would have if you just coasted to a stop, and inefficiencies of converting kinetic energy to electricity, storing it in a battery, and carrying around an electric motor to use that electricity mean you’ve almost certainly wasted more than you’d have saved by not using the brakes.
Which part of his is hard to understand?
“Give it up. Hybrid cars use less (external, ie. gasoline, diesel or grid supplied) energy than non-hybrids.”
Where did I say they didn’t?
Though, of course, they only use less energy in stop-and-start driving, and all that heavy, complex powertrain gadgetry is completely wasted on the highway.
I live in northern Vermont and we are in our second month of subzero night-time temperatures. My 40-mile commute to work typically is in temperatures of -10 to -20F each morning and returning in +20 to -10F at night. The extreme low this winter in our area was -32F. My TDI Jetta requires half the trip each way to warm up even though it leaves from an insulated garage that remains at +20-30F. How far can a wonder battery EV drive in those temperatures and how cold will the passenger compartment be?
Here in the UK it’s been calculated that if we converted to all-electric vehicles the electricity grid (FYI the whole of the UK is on the same grid, plus interconnects to France, Netherlands and Ireland) would need to double its capacity. Apparently it would cost a lot of billions – heading towards trillions- to do that. As others have pointed out there’s a lot kWh in a tank of hydrocarbon fuel. Irrelevant, but fascinating, petrol (gasoline) packs a punch about 6 times greater that nitro glycerine weight for weight.
MikeA
Just like clockwork, every 2 years the emergent, breakthrough technology is breathlessly announced.
If anyone can create a battery with anything near the power to weight ratio to a gallon of gasoline(or diesel),they will be a billionaire … assuming they can solve the liability problem.
For show me a compact energy storage package and I will show you a potential bomb.
Car crashes happen, how a high capacity storage battery reacts to being breached, mixed with random chemicals or /and shorted out is tough to anticipate.
But will be loved by the ambulance chasing crew.
Well, perusing all these comments by folks much more familiar with the topic than I,
I can see that I won’t be getting an electric car this century. Maybe in the next century.
How many soldiers injured in last 30 years due due to ignition events with lithium-sulfur dioxide batteries?
Batteries versus fossil fuels, (versus gollum, zombies and cannibals?) Smart Phone vs Zippo
http://what-if.xkcd.com/128/
If a methanol fuel cell comes along to run small appliances on a liquid “go juice” the whole game changes. An environmentalist worried about Catastrophic Anthropogenic Global Climate Impacts from energy production ought to put aside all the political and academic energy wasted in windmills and “renewables” and invest instead in research on fuel cells. Or, explain why in the 21st century we should feed the 20th century electrical grid with energy from windmills for which the technology has barely advanced since Don Quixote protested them littering his landscape in the late 16th century. Wind and wood and tides and hot-springs are not a vision of the future, they are an echo of a distance past.
I would consider the argument that methanol, a poison, would be better replaced with ethanol, a soothing consumable beverage. It does make the fuel cell technology a bit more challenging. But, reducing risks to children and idiots does offer advantages.
Advances in batter technology are always welcome but one of the coolest advances I think is Freightliners P10HH (compressed air hybrid vehicle) I believe UPS put them on test in 2009 hoping for 40-50% reductions, but I think it worked out to only 30% when relaunched in the 2012 version, but this looks real good for, say, garbage trucks which have high weight and can use slower acceleration and get high return on braking (in compressed air).
Your electric car makes no sense economically. Cost of battery replacement alone makes your “short trip” argument fall apart. Lithium baterries will be over twice the price. In addition the electricity has to be generated (from what?), converted to the battery, then to mechanical energy. What is the net efficiency, 20%?
I’m surprised you are so foolish about a technology that is so inefficient and ineffective.