Graphene batteries and supercapacitors

[RedDevil]

If I had an EV I wouldn't need to charge it in 4 minutes at home. 4 hours would be fine.
But I'd love it if a charge would take only 4 minutes en route, at the 'gas' station.

Suppose the charging stations need to charge 120 cars per hour.
They'd be able to do that with 8 4-minute chargers, or 120 1-hour chargers.
They'd draw the same power from the grid, but the charge station infrastructure needed for the first setup would be much less.

4 minute charging means you don't have to charge at home, as charging on the go won't set you back for more than a few minutes.

[freebeard]

Suppose the charging stations need to charge 120 cars per hour.
They'd be able to do that with 8 4-minute chargers, or 120 1-hour chargers.
They'd draw the same power from the grid, but the charge station infrastructure needed for the first setup would be much less.

I think there is more to it. The grid is AC while the charging is DC, so 8 inverters or 120? And one of the proposed uses for the Gigafactory is to add battery banks to the nodes on the Tesla Supercharger network.

[jamesqf]

Originally Posted by freebeard

Irrespective of heating, a fast recharge of a massive battery must be like a mini-lightning bolt passing through a cable you can grasp in your hand.

Or even something like this: Zebra

[California98Civic]

Random recheck to see the market status of graphene batteries reveals this. And rough calculations suggest my ebike would get a little more energy capacity in slightly less space and with much less weight.

"LRP TC Stock Spec P5-HV Graphene 2S LiPo 60C Battery (7.6V/8000mAh). The HV-LiPo Graphene cells offer even more power than before and can be charged up to 8.7V without problem. The improved cell chemistry generates an extremely low internal resistance and therefore less heat buildup under load. HDS-7 cell chemistry guarantees maximum performance. Specially developed for stock racing classes with highest possible voltage output for maximum speed and acceleration.

P5-HV Technology: 5mm gold plated battery plugs and 7.6V (2S) technology for maximum power
HV-LiPo GRAPHENE cells: High power LiPo cells that can be charged up to 8.70V (2S)! Maximum Power!
100% compatible for 8.40V (2S): More Power than LRP 2016 batteries at 8.40V charging!
Improved Lifetime: Highly improved lifetme when charged to 8.40V (2S) only!
HDS-7 Chemistry: Improved chemistry for low internal resistance + less heat build-up under load = Maximum power until the end of your run
5mm Gold Works Team connectors included
3C Charge current
Charge with your standard LiPo charger for 8.4V or with LiHV charger for 8.7V
Complying with the rules of the following federations and race series: EFRA, IFMAR, ROAR, JMRCA, BRCA, DMC
120C/60C LiPo Power No memory effect, extremely long lifetime.
Durable, see-through, hardcase made of high-quality synthetic material
2mm gold coated balancing connector
LRP quality approved
Specifications:
Length: 139.0mm
Width: 47.0mm
Height: 25.1mm
Weight: 332g
Capacity: 8000mAh
Nominal voltage: 7.6V
C-rate: 120C/60C
Style: TC Stock Spec
Power connector: P5 5mm Gold
Balancing connector: 2mm Gold
Charge current: 3C
Application: 1:10 Onroad TC Stock + Modified
This product was added to our catalog on March 24, 2017."

[JockoT]

And assuming you have a 625 amp charging supply, keeping a good contact is the problem. You certainly couldn't use a plug in connector. If you have a resistance in the wiring/switching/connectors of 0.01 of an ohm (100th of an ohm), the heat developed at that resistance, at 625 amps, is 3.9Kw. I worked on high current circuits and we used OFHC copper (Oxeygen Free High Conductivity), and it was a nightmare to keep connectors clean, tight and not overheating. That's why mercury switches are used in high current industrial switching.
We were operating at 1000 Amps, and the copper cables were as thick as your wrist.

[freebeard]

I'm not sure where to put this, so:

Nano aluminium offers fuel cells on demand – just add water
https://www.newscientist.com/article...ust-add-water/

[California98Civic]

Originally Posted by JockoT

And assuming you have a 625 amp charging supply... , .

I don't see why a little battery like the one described above needs such a mamoth power supply. ??

[JockoT]

It doesn't. But it does if you want to charge it in 4 minutes. You have to get all the energy you would normally put into the battery overnight in during the small time. If it takes 8 hours to charge, normally (just a number for arguments sake), you have to supply that same energy at 120 times the rate, to charge in 4 minutes. The only way you can do that at the same voltage is masses of current.

[California98Civic]

Ah. I get it. But I am just talking about an ebike, not a car. So just a 16ahr battery. Still, if it were a car, slow charge at home would be fine overnight or during a few hours. Leave the fast charging to charging stations. I imagine that as graphene tech gets better, we'll get several times the range into a battery only about as heavy as they are currently. More cycles too. That will be big.

[sendler]

If the graphene battery's main claim to fame is higher instantaneous power, that is not really what the electric vehicle needs to progress. Range versus cost versus cycle life is the big issue. And these graphene batteries cost a fortune. And what is the cycle life if you are always charging them at 12C? A large EV battery needs at least 2,000 cycles to 80% to make a 300,000 mile life so as to fulfill it's promise of being cheaper than an ICE car.
.
We already have batteries that are so large in capacity that a 2C discharge is 170hp. We don't need 90C. And as the capacity of EV batteries goes to 60 kWh as a norm, the charge rate will become more and more limited by the cable and connector (And Infrastructure if you think you are going to have a station charging 10 EV's at 250kW all the time) than the battery. Higher rates than 150kW at 400v that Tesla is approaching will require a split pack design that can run at 400v and charge at 800v to keep the current down.