Rapid recharge for electric cars.

[SkepticLance]

A new technology which will help provide personal vehicles after oil is on the way.

 

http://www.worldchanging.com/archives/002435.html

 

I quote :

 

"The Japanese tech giant announced today a new generation lithium-ion battery technology which can be recharged to 80% in one minute, with total recharge taking a few minutes more. "

 

Electric cars currently under development are stated to have a range up to 350 kms. Imagine an electric car that has a range that is a large fraction of that - say 250 km - and can be recharged in less than 10 minutes. You drive on your holiday vacation, for 200km. At that stage, you pull into a recharge spot, which might be a cafe with some charge points added. Go in for a recommended safety rest from driving and have a coffee. You pay for your coffee and recharge together, and head off for another 200 kms before another break.

 

Sounds like a pretty good idea for replacing internal combustion powered vehicles to me.

[swansont]

"A prototype of new battery (a laminated lithium ion battery with 600mAh capacity) was discharged and fully recharged 1,000 times at a temperature of 25 degrees centigrade and lost only 1% of capacity during the test."

 

600 mAh is about a quarter of the capacity if a standard rechargeable NiMH AA battery available today. That's one of the reasons it could be recharged quickly. The requirements for a car system are about 100,000 times larger (~1Wh or energy vs ~100 kWh for a car to go 350 km) You save on the current required by going to a higher voltage, so at 120 V vs 1.2 V you only need 1,000 times as much current.

 

80% of 600 mAh in a minute is ~30 amps, assuming high efficiency (at 1.2 V, which is why you could do this at home; at 120 V this would be just 0.3 A), which means ~30,000 amps for that equivalent one-minute car recharge. Or ~3,000 amps for a ten-minute recharge to 80%. The bottom line is that at 120 V, you need > 800 Amp-hours for full charge for a 100 kWh system.

 

There's no mention of how much the battery heated up, which is another limitation of charging time. The ability to dissipate heat goes down as you scale the size up, since volume grows faster than surface area.

 

The limitation for cars is not the charging time inherent to the battery.

[SkepticLance]

I dd not suggest that the rapid recharge system had been perfected. All new inventions require time to develop to achieve their potential.

 

Here is a different approach.

 

http://www.designnews.com/blog/460000246/post/470018647.html

 

I quote :

 

"Nano-titanate-based lithium batteries have greater energy density than the lead-acid or nickel-metal-hydride batteries of the old EV1. Plus, they have an even more desirable attribute: the ability to recharge in about 10 minutes as opposed to hours. For rapid charging, the Altairnano lithium titanate battery is the leading power source for automotive applications. The uncanny 10-minute recharge time is enabled by nano-materials that dramatically reduce ion travel distance while increasing the surface area available to the ions."

[swansont]

But again, the current (as it were) limitation is not the battery recharge rate, it's the ability to deliver the amount of electrical power. A gallon of gasoline contains ~10^8 Joules of energy — if it takes 10 seconds to pump that, that's the equivalent of 10 Megawatts of delivery capability. Plug-in stations don't have Megawatt capabilities.

 

Headlines about batteries that can be recharged in a few seconds or minutes have ZERO impact on electric cars. That's not the bottleneck.

[honestdude14]

I'd have to agree with swansont. Despite the loss of hope though,I could see where the charge capacity increase would be beneficial if electric cars become standard.

[SkepticLance]

A rapid recharge car would make all the difference. Current electric car developments allow for up to 350 km range. That is fine for everyday driving, but lets you down for longer distance. However, to be able to drive a large fraction of that 350 km and then recharge in 10 minutes will permit these same electric cars to travel large distances. That is the main limitation with modern electric cars.

 

In spite of that, we can expect a range of electric cars to enter the market in the next few years, even before the new rapid recharge technology. Their running costs compared to petroleum powered vahicles are much lower. Their smaller range, and overnight recharge requirements are OK if they are simply commuter or shopping vehicles.

[Cap'n Refsmmat]

The question is whether our electrical distribution systems can handle the load.

[SkepticLance]

To the Capn

 

I agree. That is a big potential problem. The government organisations and private companies that deal in electrical generation and distribution need to be cranking up their capacity right now. Preferably non carbon emitting methods like nuclear. It takes 20 years for a nuclear power station to go from conception to commission. Right now is a good time for that conception.

[Pangloss]

Headlines about batteries that can be recharged in a few seconds or minutes have ZERO impact on electric cars. That's not the bottleneck.

 

Well, it may not be THE bottleneck, but I think it will be a relevant issue regarding the acceptance of electrical automobiles (how much we have to adapt in order to use them). In fact I suspect there will be other acceptability and adaptability issues that we haven't even thought of yet.

 

 

The question is whether our electrical distribution systems can handle the load.

 

It's a good question. I've read that if every single driver were placed on the grid tomorrow, the system would be able to handle the load assuming overnight recharge. But I've never seen any analysis of additional load requirements at various percentages of daytime recharging. We all know how that would go in the real world, right? You'd get a massive spike in daytime energy demand due to 10-20% of the drivers working odd hours, taking the day off, whatever.

[swansont]

I can fill a pool with water in ten minutes if I have one of those helicopter firefighting gizmos, but if all I have is a garden hose, it's going to take all day. The hose is the problem, not the pool. By a couple orders of magnitude. The math is quite clear on this.

 

100 kwH in 10 minutes is 600 kW. A half a frikkin' Megawatt. In a commercial recharge station, you'd need the capacity to do several cars at once. For comparison, the average home uses about a kW, on average. Maybe a couple at peak. TRIUMF, the accelerator lab, drew several MW of power — this is power on an industrial scale. The infrastructure isn't there in non-industrial locations to do this.

 

And this gets worse with bigger batteries. IIRC the numbers we discussed earlier, to which Pangloss refers, assumed smaller batteries. A home could put in a dedicated 240V line, and at 20A, could recharge a battery half as large as we're discussing in ~11 hours. Of course, most people won't be driving 150 km per day. And the good news is that 50 kWh costs something like $6 (in the US).

[CaptainPanic]

The megawatt infrastructure can be built if necessary. In fact, I think that if I have to choose between building a bunch of big fat cables, or carrying tons of highly flammable liquids in trucks and pipes, I would always vote for the cables. Since we've shown we can build the current infrastructure, I am certain we can build a new one as well.

 

I think the bigger problem could be the large fluctuations in the power consumption. With 1-10 minute recharging I doubt that commuters will recharge their vehicles at night (unless there's a financial encouragement). Thousands will recharge it in the morning, causing an even larger peak in the electricity consumption.

[Sayonara]

Why would you want to charge your battery at peak hours when you can use the off-peak tariff to charge your car overnight for pennies?

[YT2095]

if these charging stations had their own batteries banked and on a regular charge current from power stations then it would work nicely.

even a simple car batt can surge 200-300 amps for a short while, so you Could get your fast charge if you really needed to.

[Sisyphus]

Why would you want to charge your battery at peak hours when you can use the off-peak tariff to charge your car overnight for pennies?

 

Given the choice, you wouldn't. But if you want to drive more than normal commuter distances in one day, it becomes necessary. Most people hardly ever drive that long, but hardly anyone never does.

 

if these charging stations had their own batteries banked and on a regular charge current from power stations then it would work nicely.

 

That's what I was thinking, too. But even that would come with it's own set of problems. Electricity is electricity, but if you're routinely swapping out heavily used batteries, quality control could be a nightmare. I wouldn't be at all surprised if we do see something along these lines, though.

[Sayonara]

Given the choice, you wouldn't. But if you want to drive more than normal commuter distances in one day, it becomes necessary. Most people hardly ever drive that long, but hardly anyone never does.

That was more in response to CaptainPanic (2nd paragraph of post #11) than a general reply to the thread:

"With 1-10 minute recharging I doubt that commuters will recharge their vehicles at night (unless there's a financial encouragement). Thousands will recharge it in the morning, causing an even larger peak in the electricity consumption."

 

/me resists the urge to state how many cars you could charge each second with a Dyson Sphere.

Edited July 14, 2008 by Sayonara³

[doG]

I think exchangeable batteries is probably the most feasible option....

[john5746]

I've seen an idea somewhere about power sharing between cars. Plug your car in and you can either have it charged or sell your excess to the system, similar to solar houses. If you have cars with solar panels and most people with full batteries charged during the night, then that may provide some relief to the power consumption during the day. Of course, this would require numerous plug-in stations be built in parking lots everywhere.

[Pangloss]

I've seen an idea somewhere about power sharing between cars. Plug your car in and you can either have it charged or sell your excess to the system, similar to solar houses. If you have cars with solar panels and most people with full batteries charged during the night, then that may provide some relief to the power consumption during the day. Of course, this would require numerous plug-in stations be built in parking lots everywhere.

 

Finally, a benefit to leaving your car out in the hot sun all day!

 

Oh no honey, you didn't park my car in the covered parking again, did you???

[swansont]

A car covered in solar panels might get you a couple of kWh — insolation values are a few hundred watts/m^2 for Northern Europe and the US, and solar efficiencies are 25% or less. That's fine if you're only driving a few miles a day, but not for any longer-haul movement. And if you're going to plug it in anyway, it's not clear to me how much this gets you for the cost.

[Pangloss]

Sure it would matter even if you're plugged in -- you're drawing less power from the grid.

 

I get that you're shining a realistic light on some of these ideas, but we've already got people standing in line to buy hybrid versions of cars that won't pay for their price differences over the regular models for 5-6 years -- even a $4/gallon. I think if we get these ideas on the street, these shortcomings will be working out by engineers and gradually improved over time.

[john5746]

Yeah, the idea was to balance the load by leveraging all those batteries sitting there in the cars. I just threw the solar panels in there, but as panels are reduced in price, as would be accelerated if a major car company starts putting them on cars - well, then the payback period is reduced. Obviously, the main focus for the infrastructure would be reducing peak loads.

 

http://www.sciencedaily.com/releases/2007/12/071203133532.htm

Edited July 14, 2008 by john5746

[Pangloss]

Cool article. This quote was particularly interesting:

 

... on average 95 percent of all cars are parked at any given time. One hour a day of car usage is the average in America.

 

Didn't know that.

[Cap'n Refsmmat]

Why would you want to charge your battery at peak hours when you can use the off-peak tariff to charge your car overnight for pennies?

 

Because if electric cars become mainstream, overnight hours are no longer off-peak.

[Sayonara]

Because if electric cars become mainstream, overnight hours are no longer off-peak.

What makes you so sure that the automotive industry will determine the marketability of energy concern tariffs? Storage heaters didn't obliterate cheap night-time tariffs when they became popular to exploit the lower rate, so why should battery chargers? Having a lower tariff at an off-peak time (and it will still be off-peak, because of comparative demands) is competitive business practice.

[Cap'n Refsmmat]

(and it will still be off-peak, because of comparative demands)

And here's the key point. My thought was that with sufficiently mainstream electric cars, all charging up at night, night-time will no longer be off-peak -- there'll be as much demand then as any other time. That clearly would not be the case unless there were a very large number of electric cars.

 

(I'm not entirely sure how the demand from charging automobiles compares to the usual night-time demand, so I may just be making crap up. But that's my job.)