EEVblog Electronics Community Forum

General => General Chat => Topic started by: Homer J Simpson on March 06, 2018, 02:13:31 pm

Title: charging up your electric car in 10 minutes - supercapacitors
Post by: Homer J Simpson on March 06, 2018, 02:13:31 pm

http://www.bbc.com/news/business-43285885 (http://www.bbc.com/news/business-43285885)
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: ikrase on March 06, 2018, 06:36:10 pm
I somehow imagine that this might involve some technical problems with things other than energy storage.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: IanMacdonald on March 08, 2018, 07:35:02 am
The only sensible electric car is one which gets its electricity from an onboard fuel cell. That is probably the way things will go in the near future once fuel cell technology matures.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: EEVblog on March 08, 2018, 11:19:30 am
If they are claiming full charge in 10 minutes then I call bullshit.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: james_s on March 08, 2018, 12:43:22 pm
I think that trying to achieve a full charge in such a short time is probably misguided. A commuter car that can be plugged in at home to charge overnight covers the majority of driving that most people do and that technology is already available. Once even a modest percentage of cars being driven this way are electric we can start working on vehicles that require longer trips and more rapid charge cycles. In the meantime, internal combustion power is going to remain with us for a while yet.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: thm_w on March 08, 2018, 12:44:49 pm
If they are claiming full charge in 10 minutes then I call bullshit.

The article is discussing using supercapacitors in cars. Charging those in 10 minutes is completely realistic, assuming the storage capacity is not very large (ie to supplement li-ion which they mention).
The title is deceptive clickbait implying existing cars could be charged that fast..

The only sensible electric car is one which gets its electricity from an onboard fuel cell. That is probably the way things will go in the near future once fuel cell technology matures.

We have completely sensible electric cars in use today using li-ion.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: BrianHG on March 08, 2018, 02:18:13 pm
If they are claiming full charge in 10 minutes then I call bullshit.
What if the car only has a 50km range?
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: BrianHG on March 08, 2018, 02:24:54 pm
The Tesla Roadster 2.0, to be released in 2020, will have a 620 mile (1000km) range on 1 charge.  Lets see some super-capacitor run a car 1000km on 1 charge and be fully recharged in 10 minutes for another 1000km of driving.

https://www.express.co.uk/life-style/cars/894267/Tesla-Roadster-range-price-performance-specs-2020 (https://www.express.co.uk/life-style/cars/894267/Tesla-Roadster-range-price-performance-specs-2020)
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: Ampera on March 08, 2018, 05:29:55 pm
Just focus on hot swap battery stations guys, maybe even a standard based on all compatible, modular cells, just more or less of them, (not up on this, likely already exists). That solves all the problems with charging, and you can top up an electric car faster than a gas car in some cases using this.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: Halcyon on March 08, 2018, 05:33:05 pm
If they are claiming full charge in 10 minutes then I call bullshit.

What are you talking about Dave? It's totally do-able. ;-)

(http://www.fredsullivan.com/wp-content/uploads/2016/12/bttf-005a.jpg)
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: Berni on March 08, 2018, 05:36:37 pm
It might charge in 10 minutes but how many kilometers can it go on that charge?

This is likely the same charging performance as Tesla superchargers. They fill it up most of the way in 30 minutes but since this supercap likely doesn't go nearly as far it proabobly takes the same amount of power to charge these capacitors in 10 minutes.

But hey as long as it creates hype
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: tautech on March 08, 2018, 05:53:33 pm
You don't need a looooong duration of power to get to 88mph..................
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: NANDBlog on March 08, 2018, 06:43:04 pm
I was testing large supercapacitors some 2 years ago. It was about half a kilogram, and some 1000s of Farads. A half kilogram capacitor had about the energy of a AA NiMH battery.
This could work for a bus line, where stops are every few hundred meters (in fact, the capacitors were for this application) but not for an electric car.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: BravoV on March 08, 2018, 08:58:06 pm
None of those scientists/engineers in the article dare to come up with hard numbers like energy needed for the "car" to move X km for a single charge of 10 minutes. The real essential info missing is what kind of car ?

Probably just another click bait where they spin off the electrical bus article ....

... or they mistakenly placed the wrong car's photo, the real one maybe for this kind of car ...  :-DD

(https://upload.wikimedia.org/wikipedia/commons/thumb/2/28/Solar_Car_Tokai_Challenger.JPG/1280px-Solar_Car_Tokai_Challenger.JPG)
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: Neilm on March 09, 2018, 07:02:44 am
Just focus on hot swap battery stations guys, maybe even a standard based on all compatible, modular cells, just more or less of them, (not up on this, likely already exists). That solves all the problems with charging, and you can top up an electric car faster than a gas car in some cases using this.

IIRC Tesla had a couple of these stations, which they closed as no one wanted to use them. It automatically swapped the battery pack on the Model S in about 90 seconds
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: NANDBlog on March 09, 2018, 07:21:15 am
Just focus on hot swap battery stations guys, maybe even a standard based on all compatible, modular cells, just more or less of them, (not up on this, likely already exists). That solves all the problems with charging, and you can top up an electric car faster than a gas car in some cases using this.

IIRC Tesla had a couple of these stations, which they closed as no one wanted to use them. It automatically swapped the battery pack on the Model S in about 90 seconds
Not Tesla, Renault and Nissan. Fluence EV was battery swappable, and a huge flop. You didnt own the battery, only rented it, and the cost was higher than a regular car.  |O
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: nctnico on March 09, 2018, 09:02:17 am
I was testing large supercapacitors some 2 years ago. It was about half a kilogram, and some 1000s of Farads. A half kilogram capacitor had about the energy of a AA NiMH battery.
This could work for a bus line, where stops are every few hundred meters (in fact, the capacitors were for this application) but not for an electric car.
The article Homer linked to states that the super capacitors are not intended as primary storage but just to handle the big current surges during accellerating and braking. It makes sense to use super capacitors there in order to prolong the life of the Li-ion batteries. I don't see super capacitors as a primary energy storage any time soon because their energy density is way to low.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: james_s on March 09, 2018, 01:18:41 pm
Yeah renting the battery isn't gonna fly, nobody wants to be stuck with another monthly fee, with a car that becomes useless if you stop paying. If you own the battery and have it swapped you could end up trading a nice new pack for one that had been heavily used and abused.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: blueskull on March 09, 2018, 02:52:19 pm
If the battery or super cap can withstand 6C+ charging, then why not? Our fast charger can directly tap into 2.3kV distribution network, and the power supply is virtually infinite.

Right now we have somewhere 300kW fast charger (another group in the same facility did this, not us), and 6*40kWh (Nissan Leaf) is only 240kW.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: Ampera on March 09, 2018, 03:03:07 pm
Maybe a hotswap station that shows the age of the batteries you can swap out, with the price of an exchange being higher or lower for a newer or older battery. You go up, get sort of like a menu of batteries, choose which one you want, pay for it, and then swap it out.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: BrianHG on March 09, 2018, 03:13:38 pm
Maybe a hotswap station that shows the age of the batteries you can swap out, with the price of an exchange being higher or lower for a newer or older battery. You go up, get sort of like a menu of batteries, choose which one you want, pay for it, and then swap it out.
If swap-able batteries came to be available in mass, can you just imagine the con re-furbished junk which will be guaranteed to eventually end up in the market.  1 day you have a good battery.  The next, you wont make it back home, though the gauge says you should be able to.  It will be the stupidest choice a consumer can make since they wont be able to confirm exactly what distance and wattage they are getting.  I prefer having a battery pack design which exceeds the available amount of driving range you can do in 1 day.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: amspire on March 09, 2018, 04:08:08 pm
I am pretty sure that hot swappable batteries would end up tracking their own performance. An inbuilt micro probably. The car has to know the available mileage. It can learn that with a single installed battery, but for swappable batteries, the information has to come with the batteries.

You would think there would have to be some kind of rules, such as when a battery pack drops to 80% capacity, it can no longer be recharged by a charging station - it has to be returned for recycling.

Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: digsys on March 09, 2018, 04:12:15 pm
Quote from: nctnico
The article Homer linked to states that the super capacitors are not intended as primary storage but just to handle the big current surges during accellerating and braking. It makes sense to use super capacitors there in order to prolong the life of the Li-ion batteries. I don't see super capacitors as a primary energy storage any time soon because their energy density is way to low.
Plus in all the work I've done with them (solar race cars), they are invaluable for heavily dampening the HUGE switchmode / ripple that exists.
I've measured up to 30V across a very wide bandwidth. Most battery chemistries only go to ~100Hz, maybe 200Hz before they start going HiZ.
2 other issues with Supercap only -
1/ Voltage output is linear with capacity - so when they are 50% depleted, you are 50% down on Vop. A disaster !!
With Lithium, we usually take Vref as 3.6-3.7V, which is ~85% of capacity. If you have a 200-300Km range, then you can push that to ~90%
3.8V-4.2V is only ~2-3%, depending on C. The rest is below 3.6V, and can be used safely, if you derate C load (I create a load profile for each pack).
2/ Given that the max voltage of a supercap is ~3.0V, the more you put in series the more "equalization current" you need across each cap !!
Unlike Li, which can hold equalization for months (again depending on C rates), these MUST be connected all the time.
By my calculations, the current volumetric ratio (total energy) is ~20X, based on what is actually available now.
They definitely have a place, but not as a complete replacement, not for a long time.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: Brumby on March 09, 2018, 04:17:16 pm
Battery swapping will not become palatable until someone creates a battery that will have an absolutely reliable and predictable state no matter what discharge conditions it faces.

This certainty is what people are used to and expect with petroleum fuels.  Maximum output until the last few drops and the predictability is high as to when that is going to happen.  For wide acceptance of electrical vehicles, the same level of certainty will be necessary - and I can't see that with hand-me-down batteries of today's chemistry.

The logistics of such a swap program are also enormous.  They may be overcome in time - but to even have a chance, there must be a viable option in the batteries themselves - chemistry, form factor and so on.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: amspire on March 09, 2018, 04:26:18 pm
2 other issues with Supercap only -
1/ Voltage output is linear with capacity - so when they are 50% depleted, you are 50% down on Vop. A disaster !!
The output voltage is linear with respect to current discharge, but not power.

When the voltage is down 50%, the power capacity is down to 25%. So between 100% and 50% voltage, there is 75% of the power.

There is probably no point going below 20% voltage - at that point, there is only 4% of the energy remaining. Obviously, if you are going to use capacitors, you design for the voltage swings.

It is possible a car could have a limp home mode that can use the last 20% of the voltage.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: digsys on March 09, 2018, 04:32:52 pm
Quote from: BrianHG
If swap-able batteries came to be available in mass, can you just imagine the con re-furbished junk which will be guaranteed to eventually end up in the market.  1 day you have a good battery.  The next, you wont make it back home, though the gauge says you should be able to.  It will be the stupidest choice a consumer can make since they wont be able to confirm exactly what distance and wattage they are getting.  I prefer having a battery pack design which exceeds the available amount of driving range you can do in 1 day.
Better place tried to push his "battery swap" model all over the world (incl Australia), and it failed everywhere. I am proud to be involved in a
team that helped rid them from OZ. Apart from what you point out, the logistics of moving 1,000s (eventually) of battery packs, and these will be huge,
around the country, to all "charge sites" is monumental, not to mention the large volume / weight of the packs. Which also, places severe limits
on vehicle design / shape / loading. Trying to standardize all makes / models would be impossible.
Easy replacement though is still VERY desirable, the packs we design can be swapped out as easily as a normal battery. They are usually app
2-3X the size, but we make sure they don't exceed ~20Kg each. It means, should something go wrong, they can be easily exchanged a station.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: BrianHG on March 09, 2018, 04:33:50 pm
I am pretty sure that hot swappable batteries would end up tracking their own performance. An inbuilt micro probably. The car has to know the available mileage. It can learn that with a single installed battery, but for swappable batteries, the information has to come with the batteries.

You would think there would have to be some kind of rules, such as when a battery pack drops to 80% capacity, it can no longer be recharged by a charging station - it has to be returned for recycling.
Ahem, haven't you heard of re-furbished printer cartridges with manipulated serial proms.  Those messed up cartridges which screw up your printer due to either ink eventually getting clogged in the print head, or, color toner speckles appearing all over your printout after a weeks use.  Do you honestly believe these batteries wont be hack-able.

And don't think this cannot happen with fuel.  Locally, a gas station was caught adding water to their fuel, just enough to make a few extra $, but, motors could still burn it.  Years ago, I was stuck going to a no-name gas station and my engine got f---ed and sand was found in my gas tank.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: digsys on March 09, 2018, 04:42:21 pm
Quote from: amspire
  ...  Obviously, if you are going to use capacitors, you design for the voltage swings ....
Designing a motor controller to work at min ~96% efficiently (ours is 98.5% min), over a wide power band is tough enough with a 20% Vin
variation, to design it at the voltage swings seen with a capacitor source is near impossible (we've looked at the idea). Maybe one day.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: julianhigginson on March 09, 2018, 04:44:23 pm
For the near future I really like the idea of cars like the chevy(holden here) volt... full electric car, with a petrol motor that is purely a generator. But for some reason, electric cars with petrol generators just aren't that popular...

For short drives you stay pure electric, and recharge off the grid where possible. As you start to extend your range, the motor kicks in to charge up the battery, which then keeps you going... I'm not sure why this hasn't been so popular? seems like a pretty good idea to me. I understand you need extra stuff (ie a motor and a petrol tank and a generator) but it means you can use existing infrastructure where needed, and the petrol motor can be far more simple than a car engine - it just needs to run at an optimum rate to get good electrical efficiency into the batteries. And no gearbox needed.

I like it better than toyota's hybrid thing.. that just seems really complicated. And you are 100% powered by fuel still.... Though admittedly it gets pretty amazing fuel efficiency...
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: amspire on March 09, 2018, 04:44:53 pm
I am pretty sure that hot swappable batteries would end up tracking their own performance. An inbuilt micro probably. The car has to know the available mileage. It can learn that with a single installed battery, but for swappable batteries, the information has to come with the batteries.

You would think there would have to be some kind of rules, such as when a battery pack drops to 80% capacity, it can no longer be recharged by a charging station - it has to be returned for recycling.
Ahem, haven't you heard of re-furbished printer cartridges with manipulated serial proms.  Those messed up cartridges which screw up your printer due to either ink eventually getting clogged in the print head, or, color toner speckles appearing all over your printout after a weeks use.  Do you honestly believe these batteries wont be hack-able.

And don't think this cannot happen with fuel.  Locally, a gas station was caught adding water to their fuel, just enough to make a few extra $, but, motors could still burn it.  Years ago, I was stuck going to a no-name gas station and my engine got f---ed and sand was found in my gas tank.
Of course they will be hackable. Just the same at petrol pumps can be fiddled with. You can have big penalties and make it hard though. Every time that battery is charged, the data can be required to be recorded - maybe to a distributed blockchain database. If one charging station has all its batteries increasing in capacity by 50% suddenly, then they get audited and the batteries they are offering are tested. Fraud is a criminal offence - they can go to jail.

I do not what what the system will be, but there would be a system. It wouldn't work otherwise.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: Psi on March 09, 2018, 04:47:20 pm
TOPIC: charging up your electric car in 10 minutes - supercapacitors

I can start my car engine in ~300ms of cranking (when it's warm) because i replaced my car battery with supercaps.
The voltage doesn't drop under 400A load, so the voltage at the starter motor is the full 13.8V instead of like 8V
It cranks over SUPER fast.

Does that count?
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: julianhigginson on March 09, 2018, 04:57:48 pm
as for a 10 minute charge on a regular electric car... yeah...

Given a 100kWh battery (tesla model s?) that's going to need charging at 600kW, before you even consider charging efficiencies...

That's some insane voltages or some insane currents (or both!) across/through the charging connector.

Come to think of it, I'd love to see what a pluggable connector for applying 600kW to something outdoors would look like. I imagine it'd be pretty big.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: digsys on March 09, 2018, 05:09:53 pm
Quote from: julianhigginson
For the near future I really like the idea of cars like the chevy(holden here) volt... full electric car, with a petrol motor that is purely a generator ....
As you start to extend your range, the motor kicks in to charge up the battery ... seems like a pretty good idea to me.
It is an excellent idea, and been around for ages .. diesel electrics .. in trains, trucks, mining machinery etc etc etc
All the EV makers have had it as an option (or planning it), and it is usually an all-in-one unit (a petrol tank swap-out?).
And as you say, it is EXTREMELY efficient, both due having a total EV drive, plus the generator is optimized JUST for charging.
The bonus is, it alleviates range anxiety. It's around, and still being developed, not sure why it isn't mentioned more though

Edit: found this, good article - www.bioturbine.org/Publications/PDF/microturbine-01-HILTECH.pdf (http://www.bioturbine.org/Publications/PDF/microturbine-01-HILTECH.pdf)
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: Berni on March 09, 2018, 05:19:24 pm
TOPIC: charging up your electric car in 10 minutes - supercapacitors

I can start my car engine in ~300ms of cranking (when it's warm) because i replaced my car battery with supercaps.
The voltage doesn't drop under 400A load, so the voltage at the starter motor is the full 13.8V instead of like 8V
It cranks over SUPER fast.

Does that count?

Now that is the correct use of supercaps.

Tho in Australia i don't think there is that much use for it since it doesn't get all that cold. Over here in Europe that would be more useful. If you have a big diesel sitting outside in -15°C all night and its battery id a fair few years old you will get some seriously slow cranking out of it. To the point where you can easily coun't how many compression cycles the engine did while you pray that it will fire up.

Lead acid batteries really get there internal resistance shooting up when they get very cold. The diesels are not only difficult to turn over due to there high compression ratio but also use glow plugs on cold starts to help it ignite and those take around 100A for a few seconds after turning the key after all that the battery has to then crank it.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: Psi on March 09, 2018, 05:24:01 pm
It's not cold here either, i only did it for fun :) and i was sick of replacing car batteries every 2 years.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: amspire on March 09, 2018, 05:26:33 pm
as for a 10 minute charge on a regular electric car... yeah...

Given a 100kWh battery (tesla model s?) that's going to need charging at 600kW, before you even consider charging efficiencies...

That's some insane voltages or some insane currents (or both!) across/through the charging connector.

Come to think of it, I'd love to see what a pluggable connector for applying 600kW to something outdoors would look like. I imagine it'd be pretty big.
The present 120kW Tesla Supercharger is something like 480v and 250A.

The 1MW Megacharger for the trucks I gather will probably double the voltage - so basically is will be 1000V at 1000A. The connector has 8 big pins, so that would be 4 circuits with 250A each. That would mean 8 copper cables of something like 12mm each. They could go thinner if they don't mind the cable getting warm. It will be heavy.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: julianhigginson on March 09, 2018, 05:39:22 pm
It's around, and still being developed, not sure why it isn't mentioned more though

yeah, It just seems really rare in practice.

I was having a think about what my next car might be the other week. I really want to move away from petrol (not like my standard western lifestyle doesn't consume plenty of petrol in supply chains anyway, but I would like to do what i reasonably can...)

But as much as I'd like a full electric car I live far enough away from where I need to get to and back from sometimes, that most EVs would not be an option. I was looking for anything to do the job without ending up in a toyota hybrid (which isn't THAT bad an option, though it's still entirely a petrol powered car)

I found the Volt, but that's not even got a current model in Australia any more. It was withdrawn from the market after just a few years of very low sales. Which is sad, because the reviews seemed pretty positive.

I haven't found any other generally available electric car with range extension this way in Australia.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: Berni on March 09, 2018, 05:39:44 pm
It's not cold here either, i only did it for fun :) and i was sick of replacing car batteries every 2 years.

Well a car battery should certainly last longer than 2 years, tho the Australian heat likely is not good for those batteries ether. But im pretty sure a supercap can extend the life of it by 3x easily. Perhaps the batteries even age slower if they are not repeatedly exposed to those large discharge currents.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: james_s on March 09, 2018, 05:50:13 pm
Yeah 2 years does seem awfully short. I just recently replaced the battery in my car that was more than 10 years old, I've had several batteries last that long.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: Berni on March 09, 2018, 08:52:06 pm
It is a question however how do the giant lithium batteries in electric cars perform after 5 years of use. Its pretty common for batteries in phones and laptops to really loose a lot of there capacity over a few years of constant cycling.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: NANDBlog on March 09, 2018, 09:46:38 pm
I was testing large supercapacitors some 2 years ago. It was about half a kilogram, and some 1000s of Farads. A half kilogram capacitor had about the energy of a AA NiMH battery.
This could work for a bus line, where stops are every few hundred meters (in fact, the capacitors were for this application) but not for an electric car.
The article Homer linked to states that the super capacitors are not intended as primary storage but just to handle the big current surges during accellerating and braking. It makes sense to use super capacitors there in order to prolong the life of the Li-ion batteries. I don't see super capacitors as a primary energy storage any time soon because their energy density is way to low.
You are right, I havent read the entire article, as it seemed like those general articles, which only concentrate on one issue.
I see that they want a hybrid capacitor-battery storage. My question is: Why? They claim that:
"Supercapacitors don't store as much energy but their response is instantaneous. So a supercapacitor could handle acceleration and energy recovery under braking - taking care of the stressful part of a battery's life - possibly doubling or tripling a battery's life expectancy."
So for example a Prius in microcycling can handle hundreds of thousands of cycles. Breaking and accelerating is microcycling, on a full electric car it is even less impact. A battery pack large enought to handle the range easily can handle the peak currents both ways.
And of course the supercap has nothing to do with the 10 minute charging.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: cprobertson1 on March 09, 2018, 10:21:41 pm
It is a question however how do the giant lithium batteries in electric cars perform after 5 years of use. Its pretty common for batteries in phones and laptops to really loose a lot of there capacity over a few years of constant cycling.

This self-reported data (https://docs.google.com/spreadsheets/d/t024bMoRiDPIDialGnuKPsg/edit#gid=0) gives you an idea of how the range degrades with time - obviously this contains confounding factors.

Nissan guarantee their batteries at 70% capacity after 5 years/60'000 miles (but I don't know how that would overlap with battery leakage figures).

It depends on the climate as well - Nissan were having problems with battery degradation in hot states, so it might be worse in some cases - while data collection on other cars suggested they might still have between 80 and 85% capacity after 100'000 miles.

New batteries are also prohibitively expensive in some cases - £100/kW (£6'500-£8'000 for a few typical battery assemblies that I had a look at) seem fairly common from a cursory google search.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: woodchips on March 10, 2018, 07:21:58 am
The snag with capacitors, super ones or not, is that they lose half the charge energy when being charged, Q=1/2CV^2. This is rather inefficient.

Lead acid batteries are not at their best in very cold conditions. But, by taking current from the battery and hence warming it up you will get more than the energy taken to warm the battery. The warm energy level is still in the battery, just that the cold stops it being used. Sneaky. So using the heater plugs is a good thing, in fact use the heater plugs for as long as you can without burning them out.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: mtdoc on March 10, 2018, 07:48:53 am
It is a question however how do the giant lithium batteries in electric cars perform after 5 years of use. Its pretty common for batteries in phones and laptops to really loose a lot of there capacity over a few years of constant cycling.

In the case of the Chevy Volt, it has a 8 yr, 100k mile warranty on its 16 kWh battery pack. There have now been many 6+ year old volts on the road with > 100k battery miles (some with >300k total miles) and at least as of a year ago or so, Chevy reported no battery replacements due to decreased capacity.  It’s worth noting that the Volt’s engineers chose to be extremely conservative in their setting of charge/discharge limits so that only the middle 80% or so of the battery capacity is used.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: nctnico on March 10, 2018, 08:56:23 am
The snag with capacitors, super ones or not, is that they lose half the charge energy when being charged, Q=1/2CV^2. This is rather inefficient.
That doesn't make sense. You can't magically loose half the energy (laws of energy preservation). What you are probably referring to is that you can't use all of the energy stored in a capacitor because at the end of the discharge the voltage will be too low to do anything usefull.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: nctnico on March 10, 2018, 08:59:35 am
It is a question however how do the giant lithium batteries in electric cars perform after 5 years of use. Its pretty common for batteries in phones and laptops to really loose a lot of there capacity over a few years of constant cycling.
Lithium batteries in cars are treated much better compared to phones and laptops which have a designed lifespan of 3 years. A good example is the Toyota Prius. As far as my information goes very few batteries failed in these cars. What they typically do is charge the batteries up to 80% to 90% and don't discharge them under 20%. That way you can get many more cycles out of a Li-ion battery. Bonus points if the battery pack is actively cooled or heated (which is missing on the Nissan Leaf BTW).
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: james_s on March 10, 2018, 09:25:22 am
When the Toyota Prius first came on the market I was certain that within a decade the junkyards would be filled with perfectly good hybrid cars that just had bad battery packs. In reality they have proven to be *far* more reliable than I ever imagined and replacement packs cost ~1/5th what they used to. My other half has a 2002 Prius still going strong on the original hybrid battery, I replaced the original 12V AGM battery a couple years ago when it failed. It remains to be seen how well the Li-ion batteries in pure electrics hold up but I know several people with early generation Nissan Leafs that are still doing fine.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: SL4P on March 10, 2018, 07:32:24 pm
(Energy + Heat) / Time = Fire
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: digsys on March 10, 2018, 07:36:55 pm
Quote from: james_s
When the Toyota Prius first came on the market I was certain that within a decade the junkyards would be filled with perfectly good hybrid cars that just had bad battery packs. In reality they have proven to be *far* more reliable than I ever imagined and replacement packs cost ~1/5th what they used to. My other half has a 2002 Prius still going strong on the original hybrid battery, I replaced the original 12V AGM battery a couple years ago when it failed. It remains to be seen how well the Li-ion batteries in pure electrics hold up but I know several people with early generation Nissan Leafs that are still doing fine

The biggest surprise is - that swapped out battery packs from ALL EVs are in HUGE demand !! We have groups of people snapping up USA swapouts
by container load (not full of course). 20% down in a car may be undesirable, but they have a LOT of other uses, especially since you know that most
are from the same batch and pretty well matched. Any extra conditioning is a snap. Tesla swap-out packs are in hysterical demand, Tesla owners
often swap them out at 5% (or less) down. They need to always beat every car on the road it seems :-)  win-win
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: Psi on March 10, 2018, 08:12:56 pm
It's not cold here either, i only did it for fun :) and i was sick of replacing car batteries every 2 years.

Well a car battery should certainly last longer than 2 years, tho the Australian heat likely is not good for those batteries ether. But im pretty sure a supercap can extend the life of it by 3x easily. Perhaps the batteries even age slower if they are not repeatedly exposed to those large discharge currents.

I'm pretty sure it's just crap/cheaper materials used, and no desire by the local manufacturers to make them last longer.
It's very common here to buy a jap import car and have the jap brand battery last for 7 years. Only to replace it with a local battery that then lasts 2-3

Also i didn't add the caps in parallel, i replaced the battery with caps. <gasp>
sure, if i leave the lights on it's flat in 4min not 2 hours, but they should outlast the car.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: NANDBlog on March 11, 2018, 12:09:03 am
It's not cold here either, i only did it for fun :) and i was sick of replacing car batteries every 2 years.

Well a car battery should certainly last longer than 2 years, tho the Australian heat likely is not good for those batteries ether. But im pretty sure a supercap can extend the life of it by 3x easily. Perhaps the batteries even age slower if they are not repeatedly exposed to those large discharge currents.

I'm pretty sure it's just crap/cheaper materials used, and no desire by the local manufacturers to make them last longer.
It's very common here to buy a jap import car and have the jap brand battery last for 7 years. Only to replace it with a local battery that then lasts 2-3

Also i didn't add the caps in parallel, i replaced the battery with caps. <gasp>
sure, if i leave the lights on it's flat in 4min not 2 hours, but they should outlast the car.
That is a good way to get stranded in the middle of nowhere.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: james_s on March 11, 2018, 04:03:49 am
A better solution might be to have a small AGM battery in parallel to the caps, that would give you the reserve capacity while the supercaps deliver the high current needed.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: tautech on March 11, 2018, 07:08:42 am
It's not cold here either, i only did it for fun :) and i was sick of replacing car batteries every 2 years.

Well a car battery should certainly last longer than 2 years, tho the Australian heat likely is not good for those batteries ether. But im pretty sure a supercap can extend the life of it by 3x easily. Perhaps the batteries even age slower if they are not repeatedly exposed to those large discharge currents.

I'm pretty sure it's just crap/cheaper materials used, and no desire by the local manufacturers to make them last longer.
It's very common here to buy a jap import car and have the jap brand battery last for 7 years. Only to replace it with a local battery that then lasts 2-3

Also i didn't add the caps in parallel, i replaced the battery with caps. <gasp>
sure, if i leave the lights on it's flat in 4min not 2 hours, but they should outlast the car.
That is a good way to get stranded in the middle of nowhere.
If you check Psi's posts, he's been running caps instead of LA batteries for years. I know he will have learnt all the pitfalls of caps by now.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: Psi on May 08, 2018, 07:45:31 pm
yes, i have. A couple of times i've done the walk home of shame.

I carry around a RC lipo battery at 'storage charge' in the glove box and a small 10A current limited DC/DC converter :)

The capacity isn't a lot with it at 40% storage charge however i don't need much to fully recharge the supercaps.
Leaving the lipo in the car at storage charge is much better for its lifespan.

The only real risky bit is going for a vehicle cert/warrant of fitness.
As I don't know how long they might leave the car with ignition on but engine off. Or leave the lights on.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: jmelson on May 09, 2018, 04:56:49 am
Gee, you could get a little hand-crank generator and probably charge the supercaps in a couple minutes, and get the car started.

Jon
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: Psi on May 09, 2018, 07:21:53 am
From memory, there's enough energy in a CR2032 to start a car once, just going to take 3 weeks to exact it all into the super caps :)
Always thought that would be funny youtube vid to make.  :-DD
Dunno how efficient the boost reg would be though.
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: james_s on May 12, 2018, 07:51:54 am
If you've got weeks to do it, the boost could be quite efficient. You could implement a charge pump without using any electronics at all, just manually wire the caps in parallel and series in turn, charging one at a time to the voltage of the CR2032. I say go for it, in the name of science! :)
Title: Re: charging up your electric car in 10 minutes - supercapacitors
Post by: rstofer on May 13, 2018, 12:54:17 am
The 2017 Chevy Bolt battery is rated for 60 kWh so to charge it in 1 hour requires 60 kW.  To charge it in 10 minutes requires 360 kW - that seems like a lot of charging current at, say, 400V - about 90 amps.

DC fast charging will currently provide 90 miles in 30 minutes of charging and these stations are sprouting up all over the place.  Besides being located outside our local pharmacy, most government buildings have stations and many private employers are installing them.  If I was still working, I'm pretty sure I would have a project to install 6 to 12 stations.  Employee benefit...

http://www.chevrolet.com/electric/bolt-ev-electric-car?ppc=GOOGLE_700000001291955_71700000017485222_58700003947879020_p31998110064&gclid=EAIaIQobChMIsd32zbSA2wIVlspkCh2DzQa7EAAYASAAEgLZz_D_BwE&gclsrc=aw.ds#charging (http://www.chevrolet.com/electric/bolt-ev-electric-car?ppc=GOOGLE_700000001291955_71700000017485222_58700003947879020_p31998110064&gclid=EAIaIQobChMIsd32zbSA2wIVlspkCh2DzQa7EAAYASAAEgLZz_D_BwE&gclsrc=aw.ds#charging)

I own the 220V charger but I have never installed it; I just use the small 120V charger.  It takes a long time to charge but I'm retired with nothing but time.