Fast-charge Li-ion cells

[bobsmith1492]

Interesting article

In case that doesn't work, a research team constructed a Li-ion cell that fully charges in 10-20 seconds.

Think about the application to an electric car, though... it would take a LOT of power to charge in that time.

From this site, it looks like the Volt has a 16KWh pack but uses about 11KWh before the gas engine kicks in. That's supposed to be the 40-mile range.

Let's say an electric car has an 80-mile range and a 22KWh battery pack made of these new cells. To charge in, say, 30 seconds would require 22KWh * 60min/h * 60sec/min /30sec:

2.64MW

That is a lot of power! There would have to be some fancy electronics to deliver that kind of power. Even if the time were increased to 10 minutes, that's still 132KW. Perhaps high-speed charge stations could have a large reservoir of capacitors or inertial energy storage...

For reference, the Cobb power plant, a large coal and natural gas plant in Muskegon, MI, generates 500MW peak which supposedly serves a population of 300,000.

 

[randay]

how much would the average lightning bolt provide?

 

[heymrdj]

This sounds like a nail in the coffin to me. What's the use of not burning fossil fuels directly if your power station has to burn a shit ton of it for each vehicle. Honestly, 2.62MW for 80 miles? That's so INEFFICIENT it's not even funny.

 

[LostUte]

Originally posted by: heymrdj
This sounds like a nail in the coffin to me. What's the use of not burning fossil fuels directly if your power station has to burn a shit ton of it for each vehicle. Honestly, 2.62MW for 80 miles? That's so INEFFICIENT it's not even funny.

Um...it has nothing to do with efficiency. 2.62 MW is not a measure of energy, but of power.

 

[Aluvus]

Originally posted by: heymrdj
This sounds like a nail in the coffin to me. What's the use of not burning fossil fuels directly if your power station has to burn a shit ton of it for each vehicle. Honestly, 2.62MW for 80 miles? That's so INEFFICIENT it's not even funny.

It's 2.62 MW for 30 seconds. Presumably your car does not travel at 9,600 mph.

This discovery changes the rate at which the battery can charge and discharge, not (AFAIK) the efficiency of doing so.

The real issues are that the wiring in your home (or in most places) has no chance of handling that, and at that charge rate it would only take 190 cars charging at once to completely swamp the power plant in the OP.

 

[bsobel]

27MW good to go http://thefutureofthings.com/n...nuclear-batteries.html

 

[Cogman]

Originally posted by: heymrdj
This sounds like a nail in the coffin to me. What's the use of not burning fossil fuels directly if your power station has to burn a shit ton of it for each vehicle. Honestly, 2.62MW for 80 miles? That's so INEFFICIENT it's not even funny.

You smokin' crack or something? This isn't a discovery of efficiency, its a discovery of fast charge rates.

Before you start typing, how about you go look up the efficiency of the electric motor and compare it to the efficiency of a gas powered motor.

Typical Li-Ion batteries operate at 80-90% efficiency. (that is, for every watt you put in, you get approx .8-.9 watts back). Typical electric motors operate around 90% efficiency.

Guess where gas engines reside? about 18-20% efficiency. Guess where gas power plants live? somewhere around 40-60% efficiency. You do the math. You think that power plants burn a lot of fuel, well think now of how much we are waisting. We are using phenominal amounts of power very inefficiently just to move our vehicles. It makes much more sense to maximize power usage on a large scale.

Not to mention the fact that electric cars have the added bonus of not really being limited to the type of power they use, instead they could use power from a nuclear plant, solar plant, wind plant, ect. They don't care.

If anything is a nail in the coffin of electric cars, it is the fact that Li-ion is fairly rare, and has a horrible problem with half-life issues. if left fully charged, it looses 20% of its maximum power capacity every year. Not a good thing. We do still need a better battery tech (Carbon nanotubes, save us!) but who knows how long it will be till anything is commercially available.

 

[CZroe]

I'm guessing that you mean 2.64MW per hour, right?

Anyway, the tiny battery that they charged in 10-20 seconds only took 6 minutes to charge normally, so it's not like it would charge just as fast when scaled up for plug-in electric and plug-in hybrid vehicles. It would charge much faster though, assuming that the improvement scales well (hopefully linearly).

 

[Cogman]

Originally posted by: CZroe
I'm guessing that you mean 2.64MW per hour, right?

Anyway, the tiny battery that they charged in 10-20 seconds only took 6 minutes to charge normally, so it's not like it would charge just as fast when scaled up for plug-in electric and plug-in hybrid vehicles. It would charge much faster though, assuming that the improvement scales well (hopefully linearly).

Um, no. MW implies a time factor (MW = MJ/s). Kind of like how your light bulbs are rated for 60 W, not 60 W/h.

Where the confusion comes in is the fact that the electric company for reasons beyond me use a measurement of kW*h (notice the *) which is a measurement of work (which is usually measured in Joules). kW*h is a very different measurement then kW/h. It is pronounced kilo-Watt hours. not kilo-Watt per hour.

 

[bobsmith1492]

2.64MW for 30 seconds is 2.64MW * 1hour/60min * 0.5min = 22KWh. That's roughly equivalent to running a 100W light bulb for 9 days straight so yes, it is still a fair amount of energy. The main problem is the raw amount of instantaneous power required for such a quick charge.

It is doable, though, with beefy electronics and some kind of energy storage to even out the draw on the electrical grid.

 

[jagec]

Originally posted by: bobsmith1492
2.64MW for 30 seconds is 2.64MW * 1hour/60min * 0.5min = 22KWh. That's roughly equivalent to running a 100W light bulb for 9 days straight so yes, it is still a fair amount of energy. The main problem is the raw amount of instantaneous power required for such a quick charge.

It is doable, though, with beefy electronics and some kind of energy storage to even out the draw on the electrical grid.

It seems to me like it wouldn't be that hard to overcome...some sort of capacitor storage that charges in 10 hours or so (drawing 2.2 kW, which is nothing), and which then charges your car almost instantly when you get back home and plug in would do it. $2/day for an 80 mile commute isn't bad at all...my econobox costs more than double that in gasoline alone.

Originally posted by: randay
how much would the average lightning bolt provide?

1.21 jigawatts.