Welcome to TMC. We need such fresh blood here
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Hydrogen vs. Battery
- Thread starter siry
- Start date
Now that you say it... I am beginning to wonder if Musk is an alien.. a plant from Andromeda..
SalisburySam
Active Member
But they can safely store absolutely huge amounts of energy. At least one roller coaster uses capacitors in its launch system. It slowly stores then quickly releases over 1 megawatt for each launch. It is a tad larger than one would like in a car to be fair. Capacitors in the 33 megajoules (about 9 kWhr but all of it released in small fractions of a second) category are in research for powering rail guns and others are being considered for carrier catapults to replace the flywheels used for energy storage in the newest carriers.
Oh yeah.
Supercapacitors can be several times more dense than lithium-ion batteries (both in terms of energy per kg and per liter), and you could add lots of armor around supercapacitor packs with that much weight and space savings.
The main problem with capacitors is self-discharge. For supercapacitors, losing only 10% of their charge per day (open-circuit) is considered "extremely low", at least when compared with the previous state of the art, which basically lost their entire charge in a day, give or take. A lithium ion battery loses about 5% per *month*. Until they reduce the self-discharge rate by close to two orders of magnitude, none of the safety concerns will even start to matter.
petit_bateau
Active Member
My #14,096 may be relevant and/or of interest
Russia/Ukraine conflict
Kadyrov reported in "critical condition". One should be skeptical of this claim as serious health issues have been reported about him in prior months as well. Yet with the recent termination of Prigozhin it is not out of the realm of plausibility. Yet another "couldn't happen to a nicer...
teslamotorsclub.com
Power density, sure. Energy density however is normally well behind that of lithium-ion batteries - and since BEVs already have plenty of power once you fit a li-ion battery of sufficient capacity to give adequate range, it's the energy density that matters for this application.
Unless you know of some new supercapacitors with vastly improved capacity?
Everyone knows you need a Flux Capacitor. Supercapacitor is an outdated concept. Obviously because Toyota is saying it is the way forward. Toyota also claim to sell EVs for decades that is 'self charging'. LOL
I think you're confusing energy with power.
Supercapacitors have excellent power density (Watt/liter) and excellent specific power (AKA gravimetric power density measured in Watt/kg) but they have poor energy density (Watt-hours/liter) and poor specific energy (AKA gravimetric energy density measured in Watt-hours/kg).
That means one can accelerate great with very small mass or volume of supercapacitors but you can't go very far on a given mass or volume of them compared to how far you can go on the same mass or volume of batteries.
Another challenge with Supercapacitors is that, like all capacitors, they have an exponential discharge curve. They output a lot of power at first but it drops off quickly:
Capacitor
Li-ion battery
For a roller coaster you get a good jolt from the capacitors and density doesn't matter since the capacitors are all on the ground.
For a car, you want the power for a long time.
I used the wrong word. I actually meant energy (Wh/kg and Wh/L). But it is possible that the numbers I found when I looked it up were wrong, or that I misread grams as kilograms or kilowatts as watts or... no idea.
Yes, the discharge curve is something that has to be dealt with, but it almost certainly isn't an insurmountable problem if the total capacity is large enough. After all, you can flatten out the curve with a switched mode regulator just by starting at some tiny fraction of a percent duty cycle and ramping up as the capacitor drains, eventually ending at a 100% duty cycle before dropping out when the capacitor drops below the low-voltage cutoff threshold for the voltage regulator.
But it is critical to have a low self-discharge rate. Nobody wants to lose an entire car worth of charge once a day, or even once a week, so a high self-discharge rate, unfortunately, would be a showstopper that would preclude the use of a lot of supercapacitor designs as power storage for automotive purposes, except perhaps to briefly store excess power from regenerative braking beyond what the battery can sink.
One more nail in the coffin...
insideevs.com
Shell Is Immediately Closing All Of Its California Hydrogen Stations
The oil giant is one of the big players in hydrogen globally, but even it can't make its operations work here. All seven of its California stations will close immediately.
insideevs.com
I was wondering how many HFCVs are out there in California. According to this article the answer is about 12,000.One more nail in the coffin...
Shell Is Immediately Closing All Of Its California Hydrogen Stations
The oil giant is one of the big players in hydrogen globally, but even it can't make its operations work here. All seven of its California stations will close immediately.
Hardly anyone owns a hydrogen car. California may pay up to $300 million for fuel stations anyway
With only 12,000 hydrogen cars on the road, and just two models for sale, California legislators are debating how much state money should support them.
calmatters.org
Similar threads
