Graphene improves lithium-ion battery capacity and recharge rate by 10x • Hacker News Board

Re: Graphene improves lithium-ion battery capacity and recharge rate by 10x

#61

Post by itsnotvalid » Thu, Nov 17, 2011, 7:55 AM UTC

KaeseEs wrote: post #35

lini wrote: post #12

Earlier quoted context omitted.

Usual Li-Ion batteries get a bit over 1000 cycles, so if this is 10 times more power, it provides more power for 150 cycles than a normal Li-Ion for its lifetime.

No they don't. Degradation of lithium-ion batteries is a function of temperature, time since manufacture and charge level rather than charge/discharge cycles. If you keep the battery cool and don't discharge it below 20% or so, it will last a very long time. If you keep it hot and constantly do full discharges, it will be dead very quickly.

Since we can't control the discharging condition and rate most of the time, and today's design often stick the battery to a heat source.

Since I am no expert in chemistry, I rather point to an article here: http://batteryuniversity.com/learn/article/how_to_prolong_li...

Basically, the capacity degrades over charge/discharge cycles. The reason is pretty simple to explain, because you can't really operate the batteries in perfect condition, it always get worse while discharging and charging it.

The other conclusion of that report points to the fact that depth of discharge is related too. So instead of using it from 100% to 0% (actually 0% doesn't mean nothing left, it just means the phone can't operate on that voltage), recharge as soon as you have a plug.

Re: Graphene improves lithium-ion battery capacity and recharge rate by 10x

#62

Post by itsnotvalid » Thu, Nov 17, 2011, 8:05 AM UTC

wanorris wrote: post #19

While this could change the game for electric cars (Edit: as others have already been discussing), it would also be an amazing advance for cell phones and computers. Imagine a cell phone that had a lighter battery but still lasted through a week of use between charges. Or an incredibly thin and light battery (and a correspondingly thin and light phone) that still lasted a couple of days. Or a notebook that didn't nee…

Or they can reduce the size of the batteries to cut weight.

Re: Graphene improves lithium-ion battery capacity and recharge rate by 10x

#63

Post by felipemnoa » Thu, Nov 17, 2011, 8:12 AM UTC

snewman wrote: post #4

Seems to me that if this proves out, and can be made affordably, the most exciting application would be electric cars -- no more range penalty vs. gasoline. Anyone know enough to comment on the likely applicability?

I would say robotics is another super exciting application, especially humanoid robots.

Re: Graphene improves lithium-ion battery capacity and recharge rate by 10x

#64

Post by sarabob » Thu, Nov 17, 2011, 9:20 AM UTC

guimarin wrote: post #43

onemoreact wrote: post #40

Earlier quoted context omitted.

Most homes have 220v devices that people use safely every day without electrocuting themselves. If your really concerned about how fast they charge just run a second line and wow it's charging twice as fast. On top of that decent charging stations are well over 90% efficient much worse than that and they start dumping a lot of heat which harms the battery. 3 * 220v/50amps * 90% efficiency will fill that 60KW/hr pack…

You don't say? they have washing machines that they plug and unplug every single day? 2 lines, why didn't I think of that. Brilliant! It's so cheap to build a 3-phase charger at 400V at 32 amps so you can charge a 20kWh pack in 2 hours (60kWh in 6!). Everyone should do it. It makes perfect economic sense! It's exactly like gas. Everytime I want to fill up my car, I sit at the pump for 6 hours. But this battery tech w…

I guess the reason that the US thinks that 220V is unsafe is the plug socket design?

Could you adopt a new plug for existing 220V appliances (AIUI you have 220v for washing machines & dryers etc?). Then over time you could migrate all your plugs to the new sockets and voilá - the whole world gets to boil a kettle in a reasonable amount of time.

Would still take 7 hours to charge your 20kWh car battery, natch.

Re: Graphene improves lithium-ion battery capacity and recharge rate by 10x

#65

Post by TheAmazingIdiot » Thu, Nov 17, 2011, 9:57 AM UTC

polshaw wrote: post #26

TheAmazingIdiot wrote: post #7

Earlier quoted context omitted.

In environmental costs, I'd much rather have FeNi chemistry fully explored. Nickel iron batteries can be abused by under and over charging, short circuiting heat, cold, vibration, and other effects and still last decades. Jay Leno has an antique car that still has a working FeNi battery. I think it needs topped off with distilled water every so often. The electrolyte is KOH so it even acts as a preservative. The only…

Why is it that people have so many diverse opinions that aren't fully informed when it comes to energy?? It may have one benefit, but 30 seconds on wikipedia informs me that it requires 5 times the mass and 20 times the volume of lithium ion to give equal energy output. Which makes it a complete non starter for anything mobile.

FeNi batteries are a wonderful storage medium for things like solar cell chargers in a house, or a wind turbine setup. I never said this is going to be the next watch battery tech.

And also, the fact is that the first cars were electric: they used various chemistries. And as I said above, Leno has a still working car that uses a NiFe battery: Cheap materials, low maintenance, not heavy metal (and nontoxic to boot).

In fact the original recipe indicated making potash, putting it in distilled water, and filtering out the physical chunks of ash.

Re: Graphene improves lithium-ion battery capacity and recharge rate by 10x

#66

Post by Maxious » Thu, Nov 17, 2011, 10:06 AM UTC

Dylan16807 wrote: post #56

ljlolel wrote: post #45

Earlier quoted context omitted.

He's talking about this patent, by the way, which I know he made: http://www.patents.com/us-5612606.html

But that patent's going to be expired by the time these batteries are ready.

Shai Agassi's patent #7,993,155 for a charging connector even references this one. Doesn't look like they consider it a problem.

Re: Graphene improves lithium-ion battery capacity and recharge rate by 10x

#67

Post by rrrazdan » Thu, Nov 17, 2011, 10:13 AM UTC

ck2 wrote: post #28

dlikhten wrote: post #5

Earlier quoted context omitted.

mmmm electric cars... 10x the range of current cars... thats what... cross country in one charge? can anyone argue with that? Ok fine 10x is not cross country... but it is 2000 miles per f-ing charge!

Can you imagine how long it would take to charge a battery that could power a regular sized car for 2000 miles? Even at 220v/30amps it might take a few days,

Why the downvotes? Shouldn't the capacity of our wires also be a limiting factor?

Re: Graphene improves lithium-ion battery capacity and recharge rate by 10x

#68

Post by Mvandenbergh » Thu, Nov 17, 2011, 10:42 AM UTC

MartinCron wrote: post #52

planckscnst wrote: post #6

Earlier quoted context omitted.

I'd rather have 200 miles and lighter/cheaper(? at least in terms of environmental costs) batteries.

Just as with gasoline-powered vehicles, I would like to have the choice of many different options.

Well, for energy storage and conversion in gasoline powered cars you only have option. Gasoline stored in a tank and combusted in an Otto cycle engine.

I don't think that people's driving behaviour is divergent enough to support multiple battery chemistries in the long run.

Re: Graphene improves lithium-ion battery capacity and recharge rate by 10x

#69

Post by dangrossman » Thu, Nov 17, 2011, 10:49 AM UTC

khafra wrote: post #38

onemoreact wrote: post #36

Earlier quoted context omitted.

You need to discharge them really slowly to if you want to keep them cool. So, there is a link between discharging and temperature assuming a high power device.

Liquid cooling for batteries wouldn't be worth it in earbuds, but it probably would in an electric car.

Which is why battery packs in Tesla cars are liquid-cooled.

Re: Graphene improves lithium-ion battery capacity and recharge rate by 10x

#70

Post by dconway » Thu, Nov 17, 2011, 12:41 PM UTC

dlikhten wrote: post #5

snewman wrote: post #4

Seems to me that if this proves out, and can be made affordably, the most exciting application would be electric cars -- no more range penalty vs. gasoline. Anyone know enough to comment on the likely applicability?

mmmm electric cars... 10x the range of current cars... thats what... cross country in one charge? can anyone argue with that? Ok fine 10x is not cross country... but it is 2000 miles per f-ing charge!

Forget electric cars. I'm building an Iron Man suit.