The Naked Scientists

The Naked Scientists Forum

Author Topic: What is holding back electric car technology?  (Read 144482 times)

Offline techmind

  • Hero Member
  • *****
  • Posts: 934
  • Un-obfuscated
    • View Profile
    • techmind.org
What is holding back electric car technology?
« Reply #50 on: 03/01/2009 00:33:41 »
Quote
It's a shame that inconsiderate car drivers often make cycling on our roads an unpleasant and hazardous activity.
As they don't pay road tax, do cyclists deserve any consideration? (I'm not advocating knocking them over on purpose.)
Is the fact that you give consideration to other vehicles got anything to do with the fact that they do pay road tax?

The alleged purpose of road tax is to fund the building and maintaining of roads; since a bicycle is so much smaller and lighter than a car, the wear and tear it causes is utterly negligible. Clearly the administrative costs would outstrip the revenue if cyclists were charged proportionately.
Many cyclists do also own a car, and pay road tax on that - and all adult cyclists pay income tax and national insurance etc.
The non-paying of road tax is a spurious argument used against cyclists.

Quote
And how many cyclists 'consider' the pedestrians they terrorise on the pavements?
But you are right - cyclists are stuck between a rock and a hard place; neither drivers nor pedestrians believe they should be on 'their turf'. Cycles travel substantially faster than peds, but frustratingly slower than cars - no wonder they're hated.
 

lyner

  • Guest
What is holding back electric car technology?
« Reply #51 on: 03/01/2009 17:10:47 »
The reason that most motorists criticise cyclists is that there are some very BAD road users amongst the cycling fraternity. How many of them obey the road signs, stop at red lights and position themselves properly? They actually get in the way.
When I cycle, I behave as if in a car and do my best not to piss off other road users. I am in a minority.
The regulations which aim to prevent total novices and total idiots from driving cars may not be 100% effective but there is nothing of the sort to protect us from badly behaved cyclists. That's why all cyclists suffer from general resentment. Unfair, but based on experience. It's an unfortunate 'us and them' situation but with reason.

Non payment of road tax by cyclists is fair enough but why not demand that all road-using cyclists must have third party insurance? Cyclists who cause accidents and consequential damage would be priced off the road because their premiums would get higher and higher.
« Last Edit: 03/01/2009 17:15:46 by sophiecentaur »
 

Offline BenV

  • Neilep Level Member
  • ******
  • Posts: 1503
    • View Profile
What is holding back electric car technology?
« Reply #52 on: 03/01/2009 19:43:57 »
When I cycle, I behave as if in a car and do my best not to piss off other road users. I am in a minority.

The majority of cyclists here in Cambridge do too - I think you're probably not in the minority, just more likely to notice those inconsiderate cyclists.

I'm certainly a considerate cyclist, but have seen some who are not - same goes for driving.  I suppose the difference is that a dangerous cyclist is far less likely to kill someone than a dangerous driver.
 

lyner

  • Guest
What is holding back electric car technology?
« Reply #53 on: 03/01/2009 21:25:29 »
Cyclists have the same problem as youths in hoodies.

There are a lot of idiots in Brighton, however, who do not have cars but do have gallons of youthful testosterone which provides them with a personal force field which they are convinced will protect them from all harm. Never be surprised to meet one coming towards you up a one way street. if you appear cross, he will just be cross back at you!!
 

Offline teragram

  • Sr. Member
  • ****
  • Posts: 122
    • View Profile
What is holding back electric car technology?
« Reply #54 on: 05/01/2009 17:38:16 »
We seem to have departed somewhat from the general thread.

If electric cars become common:-

Yes, the electricity grid will need to be expanded to cope with the demand. It has always expanded to cope with demand. The grid was not built at the start of the last century with the capability it has today. If all car companies decided tomorrow to start building production quantities of electric cars, it would be some years before they all started to hit the streets, and even then many people would continue to support the internal combustion engine sacred cow for old times sake.
In other words, grid capability is a problem, but not insurmountable.

Yes, the battery car cannot hope to match the range of an old fashioned car, until technology improves further. But most car journeys are well within the range of even traditional battery vehicles.
The charging problem is always stated as the time required to charge from zero to maximum charge. The energy lost from a battery on the short journeys which most are, will be replaceable comfortably during the time the vehicle is idle, even without vast changes to electricity supplies.  
Incidentally, the solution of changing batteries instead of recharging on-board is not a new idea, but is a good one (maybe to address the long range trip when necessary).
In other words, range is a problem, but not insurmountable.

Yes, there are problems with the risk of Li-ion batteries exploding, although not I think with ultra-capacitors. We hear of computers bursting into flame. But that was some time ago. Is it still going on? Batteries such as that in the Tesla are made from a large number of small devices. Maybe the explosion problem can be contained to a small area of the total. Also, it is not true that Li-ion battery development is only concerned with increasing capacity. Efforts are being made to solve the explosion problem, in fact at the moment, to the detriment of capacity. Given that the battery car becomes common, other battery technologies will be developed which are even more suitable.
Yes, the explosion risk of Li-ion batteries may be a problem, but it is not insurmountable.

« Last Edit: 05/01/2009 17:43:00 by teragram »
 

Offline Doug Saga

  • First timers
  • *
  • Posts: 5
    • View Profile
What is holding back electric car technology?
« Reply #55 on: 12/03/2009 16:21:11 »

newbielink:http://www.dailymail.co.uk/sciencetech/article-1161274/Scientists-develop-mobile-phone-battery-charged-just-10-seconds.html [nonactive]

Scientists develop mobile phone battery that can be charged in just 10 seconds

By David Derbyshire
Last updated at 7:31 PM on 11th March 2009

Thing of the past? The new mobile phone batteries will be recharged in just 10 seconds

A revolutionary mobile phone battery that recharges in 10 seconds instead of several hours has been created by scientists.

The new device charges 100 times as fast as a conventional battery and could also be used in phones, laptops, iPods and digital cameras within just two or three years, they say.

The same technology could even allow an electric car to be charged up in the same time that it takes to fill a conventional car with petrol - removing one of the biggest obstacles to green, clean motoring.

The quick-charge battery is the brainchild of engineers at the Massachusetts Institute of Technology.

The MIT team say their invention uses materials already available to battery manufacturers and would be simple to mass produce.

The invention is based on conventional lithium ion rechargeable batteries found in most cameras, phones and portable computers.

Lithium ion batteries are used in portable gadgets because they  store a large amount of energy in a small space.

However, they are also relatively slow at recharging - which can be a nuisance for anyone who forgets to charge up their phone overnight.

Dr Gerbrand Cedar, who devised the new battery, said: 'Electric car batteries have a lot of energy so you can drive at 55mph for a long time, but the power is low. You can't accelerate quickly.'

Dr Cedar and colleagues have now found a way of speeding up this process, the science journal Nature reports.

Conventional lithium ion batteries contain two electrodes - one made from lithium and one from carbon - submerged in a liquid or paste called an electrolyte.

When a battery is being charged up, ions - or positively charged atoms - flow from the lithium electrode to the carbon one. When a battery is discharging, the ions flow the other way.

The new battery could also work with rechargeable cars

Charging up or discharging a battery is slow because it takes time to 'detach' the ions from one electrode and absorb them into the other.

The researchers took a conventional electrode made from lithium iron phosphate and altered its surface structure so that ions were released and absorbed 100 times more quickly than normal.

A prototype made using the new technique could be fully charged or discharged in just 10 to 20 seconds. A similar sized ordinary battery takes six minutes to charge.

Unlike other battery materials, the new material does not degrade when repeatedly charged and recharged. That could lead to faster batteries lasting between two or three years, they said.

'The ability to charge and discharge batteries in a matter of seconds rather than hours may open up new technological applications and induce lifestyle changes,' Dr Ceder said.

The technology could also usher in a new generation of smaller, lighter batteries that allow phones and handheld batteries to be the size of credit cards.

Although the invention will be popular with owners of electronic portable gadgets - who will no longer need to remember to keep them charged up overnight - it could also usher in a new era of electric cars.

Bigger batteries for plug in electric cars could charge in just five minutes - compared with about eight hours for existing batteries.

Owners of electric cars would be free to drive long distances, safe in the knowledge that they could top up their battery in a few minutes at a service station - just like the owner of a petrol or diesel car.
 

Offline Pumblechook

  • Hero Member
  • *****
  • Posts: 569
    • View Profile
What is holding back electric car technology?
« Reply #56 on: 12/03/2009 18:00:16 »
Have you worked out the power required to fast charge a high capacity traction battery?..  The volts and amps required.


« Last Edit: 12/03/2009 21:34:02 by Pumblechook »
 

lyner

  • Guest
What is holding back electric car technology?
« Reply #57 on: 12/03/2009 19:28:34 »
We've been here before. It's the power supply that the filling station would need that's the problem.
If you need to charge a 2000Ah battery in 1/100 of an hour (i.e. less than a minute) you would need to charge at 200,000A. That's going to need around 1,000A of mains power for each vehicle being charged. Then there's all the heat that it would produce during charging.
A petrol pump gets the energy in with much less fuss.
 

Offline Pumblechook

  • Hero Member
  • *****
  • Posts: 569
    • View Profile
What is holding back electric car technology?
« Reply #58 on: 12/03/2009 21:35:38 »
How big would a 200,000 Amp plug be?

 
 

Offline wolfekeeper

  • Neilep Level Member
  • ******
  • Posts: 1092
  • Thanked: 11 times
    • View Profile
What is holding back electric car technology?
« Reply #59 on: 12/03/2009 23:41:21 »
We've been here before. It's the power supply that the filling station would need that's the problem.
If you need to charge a 2000Ah battery in 1/100 of an hour (i.e. less than a minute) you would need to charge at 200,000A. That's going to need around 1,000A of mains power for each vehicle being charged.
Not necessarily. There's a difference between peak power and average power. Having a battery in the filling station would considerably reduce the peak. You only have to supply the charging station at average power, not peak power; and being able to charge faster doesn't necessarily change this much.

But you'd need a heck of a lot of new power stations to supply all the energy for electric cars.

On the upside though, having a lot of electric cars plugged into the mains can completely flatten out the grid's load, and you end up with somewhat cheaper electricity, since they can supply peak power from electricity they absorbed at base load prices.
 

Offline Pumblechook

  • Hero Member
  • *****
  • Posts: 569
    • View Profile
What is holding back electric car technology?
« Reply #60 on: 13/03/2009 11:34:16 »
I did follow that about average and peak.

If you need to store X energy (Megajoules or kWH) in a battery and you want to do it quickly you need a lot of power and the current is very large.  You can't wave a magic wand and get around the laws of physics.
 

lyner

  • Guest
What is holding back electric car technology?
« Reply #61 on: 13/03/2009 12:16:50 »
wolfekeeper
Storing energy at the filling station would cost a lot -  the efficiency of such a fast cycle could be quite low (I2R losses, mainly - there is a lower limit to the possible resistance of cables). That applies to the whole notion of very rapid charging, in fact.

I  heard the BBC News item about the 'new' battery technology and saw the joke animation to show how it worked. Ab fab for phones, drills and toothbrushes, though, even if the car application is a bit hopeful.
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 12001
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
What is holding back electric car technology?
« Reply #62 on: 13/03/2009 12:59:51 »
A lovely idea Doug, there seems to be some downsides to it though. AS SC writes, there will be a lot of really strong 'powerplants/filling staions' needed. And a whole lot of new electro magnetic fields too I presume? All of them interfering with biological materials like our body's and brains. We have this ongoing experiment with mobile phones already:) All over the world, but I guess that would just become a teardrop in the ocean if this cheme was put into motion.
 

lyner

  • Guest
What is holding back electric car technology?
« Reply #63 on: 13/03/2009 13:23:20 »
You can't beat a good cheme, can you? lol
 

Offline teragram

  • Sr. Member
  • ****
  • Posts: 122
    • View Profile
What is holding back electric car technology?
« Reply #64 on: 14/03/2009 17:38:47 »
Charging a 50 or 60 KWh battery in a few minutes requires a huge amount of current. But in these discussions the requirement for charging a COMPLETEY flat battery is the only one mentioned.
A battery powered car would charge overnight, every night, while standing idle. It might even be charged while parked at a place of employment, or in public car parks. It need not be charged at a super fast rate. Whatís more, the length of most car journeys means that an overnight charge would easily top-up the battery.
It short, the requirement for charging from dead flat will arise infrequently for most people.
Charging stations will probably cope quite easily.
A battery powered car could even allow me to store electricity at night rate cost for use next day instead of high cost day rate. (My car is often unused for periods of days).
One advantage however of fast charging capability is that whilst driving, much more of the energy currently lost in braking would be recoverable. I understand that in vehicles powered by existing batteries, only about 15% of the energy required for braking can be absorbed, the limit being damage to the battery. With fast charge batteries, this figure rises I think to 85%, leading to even higher efficiencies, most noticeable in town driving, where the I.C. engine is at itís worst.

 

Offline wolfekeeper

  • Neilep Level Member
  • ******
  • Posts: 1092
  • Thanked: 11 times
    • View Profile
What is holding back electric car technology?
« Reply #65 on: 14/03/2009 18:37:32 »
wolfekeeper
Storing energy at the filling station would cost a lot
No, you just have a battery at the filling station of similar technology to the car per filling station. Either these batteries are affordable or they are not.

Quote
the efficiency of such a fast cycle could be quite low (I2R losses, mainly - there is a lower limit to the possible resistance of cables).
Nah. Thick conductors have negligible resistance.

So far as I can tell, there really isn't a practical limit here. It's just a question of charging the individual cells in the car largely in parallel, if you want to go faster you need large contact area for the plug, and the highest voltages you can sensibly manage. It's not rocket science.
 

Offline Pumblechook

  • Hero Member
  • *****
  • Posts: 569
    • View Profile
What is holding back electric car technology?
« Reply #66 on: 14/03/2009 19:18:53 »
It is not rocket science.  It is heavy engineering.

 

lyner

  • Guest
What is holding back electric car technology?
« Reply #67 on: 14/03/2009 20:25:51 »
Using two battery cycles (car plus filling station) involves twice the cost of battery capacity and twice the loss of a charge / discharge cycle.

Thick - REALLY thick - conductors are very costly. This is why they use high voltage transmission. Even short connecting cables would pose a problem. The batteries themselves would get hot because of their finite internal resistance. Remember, when you're talking in terms of thousands of Amps and low (battery vehicle) voltages, you would need only milliOhms of internal resistance  or less.

What about the internal connections in the car - for charging? Even they would need to be great lumpy bits of copper and the contacts? Not a trivial job. It's actually very much like rocket Science because of the huge powers involved.

Any engineer (me and several who I know, at least) will tell you that the numbers actually count. Once you are talking megaWatts, you are in a different electrical ballpark.

A filling station will have to be the equivalent of a significant mains distribution substation. You would need to include the energy storage factor, too.

Each vehicle would need a charge of 200kWh of energy (conservatively - 20kW for 10 hours running). This would have to be delivered withing, say, two minutes to compare with filling with petrol. That's 200X30 = 6MW! per vehicle on the forecourt. Efficiency will be very poor at that rate of charge so you could increase that to 10MW. That is some serious engineering infrastructure.
It's not impossible to envisage for a prototype, one off, demonstration but, as an alternative to the present petrol dispensing system, it's very problematical.
 

Offline wolfekeeper

  • Neilep Level Member
  • ******
  • Posts: 1092
  • Thanked: 11 times
    • View Profile
What is holding back electric car technology?
« Reply #68 on: 14/03/2009 20:39:10 »
Nah.

First thick conductors are not costly. A 1 inch (2.5 cm) square one meter long aluminium bar weighs about a 1.7 kg, and has a resistance of 43 microohms, and costs about ~$17 ish. If that's carrying 1000 amps, it has a voltage drop of only 43 mV and a power dissipation of 43 Watts. And you probably wouldn't make it square cross-section, you could make it as a sheet, because it's easier to manufacture and it dissipates heat well.

In a filling station, unlike in power transmission where you are going tens of kilometers you're only going a few meters at most. The difficult bits are the connectors, but I don't see any show stoppers there either.

And in the car, you're only going a couple of meters distance or so. Again, not particularly an issue, and the conductors are not especially heavy in the context of a complete vehicle.
 

Offline wolfekeeper

  • Neilep Level Member
  • ******
  • Posts: 1092
  • Thanked: 11 times
    • View Profile
What is holding back electric car technology?
« Reply #69 on: 14/03/2009 20:40:17 »
Also, on the cost front, so what if it costs twice as much on wear and tear on batteries to fill up quickly (yours and the filling stations)? You don't do it that often, mostly you plug in at home.
« Last Edit: 14/03/2009 20:42:42 by wolfekeeper »
 

Offline jujusalvador

  • First timers
  • *
  • Posts: 4
    • View Profile
What is holding back electric car technology?
« Reply #70 on: 14/03/2009 22:56:32 »
what is holding back the electric car technology, are the producer companys... and all of us all!

is stupid that we can regenerate energy with braking systems, but no one ever implemented nothing about regenerating energy from moving velocity, because they now, that with that kind of system or with covered technologies like magnetic generators or selff running motors we will never need to charge our cars, and will be forever free , independent of Electric/Fuel Bills, and dont ever will pollute the nature.

you are all arround the question, like everyone else, and dont see the basic point... this is simple and pure like fresh water! is not about fast charge battery's, or big capacity batterys...

what will resolve the electric cars, if they will go charge at the electric grid? that is almost all deppendent of carbon, petrol or nuclear?

you can continue using fuel cars, its all the same!!
 

lyner

  • Guest
What is holding back electric car technology?
« Reply #71 on: 14/03/2009 23:33:36 »
Wherever you get it from, the supply industry will have to change considerably to allow for increased consumer demand.  But that's no objection in principle.

Is there data on the internal resistance of these new cells? The news items talk on a more superficial level. The reduced 'time' for ions to be transferred must relate, somehow, to the effective internal resistance. I don't know enough about the nuts and bolts of electrolysis to come to a conclusion.  It would certainly need to be lower than a conventional car battery if the internal dissipation is to be less than several kW - which would cause boiling during a "five minute" charge.

On the 'details' of cost, the financial advantage will only be there if you can actually limit the inefficiencies. A double charge cycle is not an insignificant factor in cost if the efficiency of one cycle is less than, say, 80%.

I am very positive about the use for low power devices - I'll go for it as soon as I can afford a camera battery, for instance.

It's just scaling it up by a factor of several thousands which I am not convinced about, yet.

As jujusalvador says, the whole system needs a total change of mind set about efficiency and demand before any invention will significantly improve matters. With electric powered vehicles, we have the chance to make use of regen braking and better control / feedback to make the driver realise just how much energy is being used up a any one time. I have recently bought a car with instant mpg display and it is very revealing - and sobering.
 

Offline teragram

  • Sr. Member
  • ****
  • Posts: 122
    • View Profile
What is holding back electric car technology?
« Reply #72 on: 15/03/2009 17:27:30 »
You don't do it that often, mostly you plug in at home.
Hear, hear!!
 

lyner

  • Guest
What is holding back electric car technology?
« Reply #73 on: 15/03/2009 21:27:29 »
Not in your existing home, you don't. It will still need a new supply.
 

Offline wolfekeeper

  • Neilep Level Member
  • ******
  • Posts: 1092
  • Thanked: 11 times
    • View Profile
What is holding back electric car technology?
« Reply #74 on: 15/03/2009 23:09:46 »
My household supply could fill up a 50 kWh battery as used by Tesla Roadster just fine thanks, overnight, from completely empty.

I mean, even the cooker circuit is rated at 7.2 kW. It could do that in 7 hours.

And my daily commute is nothing like the 200+ miles that the Tesla manages; more like 20.
« Last Edit: 15/03/2009 23:12:32 by wolfekeeper »
 

The Naked Scientists Forum

What is holding back electric car technology?
« Reply #74 on: 15/03/2009 23:09:46 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums