Now here's a claim: EVs fully charged 'in seconds'

[Garlan Garner]

I'm not an engineer nor do I claim to know a lot about supercapacitors but as far as my understanding of them goes would it make sense to use them as the charging part of a battery within the vehicle?

Right now our problem is the taper. We can pump 120kW into the batteries with current supercharger tech for a limited time. After that the taper kicks in for two reasons;

- Heat
- Battery voltage gets high enough (4.2V per cell) that you need to start tapering in order to prevent overcharge.

Heating is being solved with every iteration of pack as P100D showed us. Couldn't super capacitors of some capacity (20% of battery's capacity) be installed into the car? My imagination is as follows; (all numbers figuratively speaking)

- You plug in with an empty 120kWh pack. Start drawing 120kW. After 40 minutes you are 65% full and your taper is supposed o kick in.
- Instead the power is diverted into capacitors and they're charged up, even faster, in seconds. (24kWh)
- You drive away and the capacitors start bleeding off their charge slowly to charge the batteries. So while you drive, park somewhere etc. batteries get that extra 20% juice at a comfortable rate.

Could this be possible? Seems very reasonable to my 'research only' point of view.

I totally understand and agree with your post. Especially when you mentioned the risk of thermal runaway. I've personally experienced that.

The only thing concerning the capacitors is that someone will have to find a place to put them. As you probably already know...the density of capacitors is not nearly what the density of 2170 batteries are.

I have some Maxwell Super Capacitors hooked up together and I can jump a frozen semi with them. However the Semi only gets 2 shots at a startup and then the Capacitors are dead. Good think about Super Capacitors though....they have no memory and they won't overcharge like LifPo's will

In todays technology:
Super Capacitors are sprinters.
Batteries are Marathoners.

The gap is closing every day....however right now..... BAU.

 

[Garlan Garner]

I'm not an engineer nor do I claim to know a lot about supercapacitors but as far as my understanding of them goes would it make sense to use them as the charging part of a battery within the vehicle?

Right now our problem is the taper. We can pump 120kW into the batteries with current supercharger tech for a limited time. After that the taper kicks in for two reasons;

- Heat
- Battery voltage gets high enough (4.2V per cell) that you need to start tapering in order to prevent overcharge.

Heating is being solved with every iteration of pack as P100D showed us. Couldn't super capacitors of some capacity (20% of battery's capacity) be installed into the car? My imagination is as follows; (all numbers figuratively speaking)

- You plug in with an empty 120kWh pack. Start drawing 120kW. After 40 minutes you are 65% full and your taper is supposed o kick in.
- Instead the power is diverted into capacitors and they're charged up, even faster, in seconds. (24kWh)
- You drive away and the capacitors start bleeding off their charge slowly to charge the batteries. So while you drive, park somewhere etc. batteries get that extra 20% juice at a comfortable rate.

Could this be possible? Seems very reasonable to my 'research only' point of view.

Also....
As we also know....

In order for a capacitor to charge a battery it has to be connected in parallel with the battery. Lets assume that both the capacitors and the battery were fully charged. Now we connect them both to a motor. The issue would be that current will take the path of least resistance. If you have a motor that is being supplied by power from a battery and a Super Capacitor...the Capacitor will discharge first because its less dense than a battery and provides the path of least resistance to the motor.

Lastly, charging a battery with a capacitor is the opposite of what I would suggest a Super Capacitor should be used for. In a car like a Tesla.....the battery should be charging the capacitors. Especially for Ludicrous Mode. The Capacitor can discharge much faster and cooler and safer than what a battery can.

Right now...universities have 2 races in front of them concerning Super Capacitors.

1. Do we make more room in Cars to support existing Super Capacitors?
2. De we make SuperCapacitors smaller with the same capacity resulting in increased density per sq mm?


Most importantly.....How in the world would someone crash test a Super Capacitor car? Each test would be a colossal failure or a raving success.

Again... Super Capacitors are some of the most dangerous products that you would ever want to short out. They have the ability to discharge ALL of their potential faster than any battery could. They will vaporize wires if shorted or connected improperly. I've seen it as I was temporarily blinded by a colossal blunder with Super Capacitors on my job.
Its a horrible sound / sight / feeling and overall experience.

 

[Saghost]

In order for a capacitor to charge a battery it has to be connected in parallel with the battery. Lets assume that both the capacitors and the battery were fully charged. Now we connect them both to a motor. The issue would be that current will take the path of least resistance. If you have a motor that is being supplied by power from a battery and a Super Capacitor...the Capacitor will discharge first because its less dense than a battery and provides the path of least resistance to the motor.

As I posted above, I think you'd have to take the e-Loop approach - isolate the Supercap behind a DC-DC converter for both charging and discharging. Otherwise you can't get much power out of the Supercap, because any change in voltage there will be reacted by the battery.

The crash safety part worries me, and I don't have an easy answer for it. I suppose you could give it something like the MSD many cars have for the battery pack - a link in the sequence that can be removed or separated by pyrotechnics which leaves the capacitor chain incomplete with both sides having one end floating. As long as the supercap's housing remains intact that should keep things safe. Not sure there's anything you can do if the housing is breached.

 

[Garlan Garner]

As I posted above, I think you'd have to take the e-Loop approach - isolate the Supercap behind a DC-DC converter for both charging and discharging. Otherwise you can't get much power out of the Supercap, because any change in voltage there will be reacted by the battery.

The crash safety part worries me, and I don't have an easy answer for it. I suppose you could give it something like the MSD many cars have for the battery pack - a link in the sequence that can be removed or separated by pyrotechnics which leaves the capacitor chain incomplete with both sides having one end floating. As long as the supercap's housing remains intact that should keep things safe. Not sure there's anything you can do if the housing is breached.

I agree.

Lets see what happens.

 

[roblab]

I don't think that it's the charging that's the problem. As several have pointed out, we charge in seconds already: Plug in, Unplug; Total, 15 seconds. Other than that, the amount of time "wasted" while we wait for a charge, even on a trip, is minimal. Go to Bathroom, Wash hands (of course), order food, Eat, Pay, Call up Tesla App and notice car is past charging what you need to get to next stop. If you are sitting in your car, waiting, maybe you might should not skip the wash hands step....

The big advantage of SuperCaps is weight savings, but right now there are too many other problems, and Tesla has chosen at least one of the best paths (you notice no one else is even close). And I would bet that those amazing engineers at Tesla are already doing calculations on the next "best path".

 

[JeffK]

The big advantage of SuperCaps is weight savings

Weight savings? Maybe you're talking about a future technology because today's super capacitors need to be about 5-20 times as heavy as Li-Ion batteries for the same amount of energy.

 

[thegruf]

^ and this is why there are all kinds of promising energy storage technoloigies but for automotove power thay have to tick all the boxes of
power to volume
power to weight
speed of charging
high power discharging
low self-discharge

and of course
longeivity - unless some form of rapid replacement can be established, which is unlikely as it has been largely negated by Tesla demonstrating it is quite feasible to carry all the power you need with you.

The above all has to be achieved with a viable economic and environmental model which includes use/extraction of raw material and recylability.

There is a huge amount of effort going into energy storage worldwide, and different solutions will be optimal for different applications.

So you can absolutely put your Christmas sweater on the fact that Elon and Tesla (as are many other people) are watching all developments like hawks. Not much fun building a Gigafactory only to find somebody just turned the world upside down by inventing something better in their kitchin.

and as a final observation -

Stability - high power density inherently defines a lot of energy in a small space ...Boeing Dreamliner batteries and Samsung Galaxy Note 7 serve as excellent reminders of what can go wrong and the spectacular costs if it does. An automotive screw up would make these look like small change.

 

[deonb]

My car charges in 30 seconds of my time. 15 seconds to plug it in at night, and 15 seconds to unplug in the morning.

If it takes you 15 seconds to unplug you might need to visit the gym more often...

 

[JeffK]

Stability - high power density inherently defines a lot of energy in a small space ...Boeing Dreamliner batteries and Samsung Galaxy Note 7 serve as excellent reminders of what can go wrong and the spectacular costs if it does. An automotive screw up would make these look like small change.

High power density and instability do not always go hand in hand. The two instances you noted were due to manufacturing issues. In Samsung's case they were cutting corners.

You mentioned another box supercapacitors have yet to check, they have a high self discharge rate. It's a problem I don't think anyone has been able to solve yet.

 

[wycolo]

All of which points out how successful the RiverSimple car seems to be at cleverly maximizing all its systems (although oddly the video avoids showing how the 4 wheel e-braking brings the car to a full stop). The capacitor bank is just large enough to provide acceleration onto UK motorways, but could it climb from Silverthorne, CO to Eisenhower Tunnel? Once the bank is depleted there remains only the base 14 horsepower that the H2 reactor can muster, so you might have to creep up in the bicycle lane. The UK has no mountain grades I'm guessing. The business model does seem attractive (how I forgot all about the Hindenburg and came to love my Fuel Cell car).
--

 

[McRat]

The highest point in the UK islands is 4400' in Scotland.

Not as flat as Florida but pretty dang flat.