Electric car batteries with five-minute charging times produced
theguardian.com
theguardian.com
* Someone has just invented a 1 minute charge time car battery. They want you to design the cable for the user to plug the car into the charge station. Can you sketch some design ideas and point out the pros and cons of each?
It's a great question because it's almost impossible... Any cable that can deliver the tens of megawatts needs a ton of copper and a ton of cooling, and usually ends up too heavy for grandma to move. Then high voltages are investigated, leading to insulators which can't do high temperatures, are stupidly thick themselves, or are non-flexible... Sometimes candidates suggest superconductors, but then they need to come up with an answer to cooling, keeping it flexible, and stopping the user getting frostbite.
As an interviewer, it shows me how quickly a candidate can guess the magnitude of each parameter in their design and iterate designs to get everything reasonable. That ability tends to match an engineer who can make a prototype of something in a few days.
Diesel might be closer to 50MW? But regardless, it's not 33kWh per gallon of energy to the wheels. Most of the energy is wasted. So of course a battery electric truck wouldn't require that much energy to do the same work.
I've seen that trucks and buses just use multiple charging cables. But yeah, you'll never charge a large truck from 0 to 100% in 1 minute. Overnight charging will be the norm.
Park car roughly in the correct place, and wait. No more issues using any cable technology that’s appropriate like coolants or the sheer cable mass in terms of copper. The robot can be built to match , and every charging port makes a nice standard looking target for vision tracking and alignment to drive the robot to the right place every time.
Edit: Obviously, a car should accept only the "tiers" that it is rated for, but the charging station and the car can negotiate which "tier" that they would like to charge.
This is what I mean by "movable stand": https://www.slimlinewarehouse.com.au/movable-lcd-tv-stand/tv...
And that's a fairly tiny battery as far as electric cars go. A Tesla 3 with the new 82kWh battery pack would require over 1MW.
On a related note there was an article[1] in the news here just yesterday about how building the charging infrastructure is challenged by the fact that the cost of expanding local transformer stations has to be shared by those wanting the extra power, like say a gas station wanting to add EV charging stations. This cost can be quite high due to the power requirements.
[1]: https://www.nrk.no/norge/ma-ut-med-mer-enn-25-millioner-for-...
That would be the fast charging option, for at home charging you'd have to use the regular slow plug.
To achieve that, substantial capacity and lifespan tradeoffs are made, and you're right that cooling becomes necessary.
7500 amps isn't 'bigger than car' territory either. If you're happy to have copper the thickness of your forearm it wouldn't melt at 7500 amps, even with simple air cooling. "Not melting" isn't quite the standard we're after, but shows that it isn't unachievable.
>>Some RC car batteries are "60C" indicating they can do a full discharge in 1 minute.
I mean, plenty of batteries can discharge that quickly, but that isn't synonymous with them being able to charge that fast, no? I can think of several examples of batteries, both Ni-Cd as well as Lithium which can be safely discharged fully at very rapid speeds, but you can't(shouldn't?) charge them that quickly.
In all seriousness, its hard for people to understand the values required and how scary those numbers in reality are.
Petrol is great source of energy as it relatively non-violent, only compressed and combusted it will explode.
Batteries on the other side are outright terrifying. Google people stabbing their phone batteries and see how violently they discharge. Scale that 4000mAh phone battery to the electric car.
I would be terrified if something went wrong with charging station that could do a under 10mins charges. Materials getting older a crack in insulation and you are toasted.
In fact, many single offshore wind turbines are capable of generating a lot more than 6MW. GW's Haliade-X tubines have an output of 13MW each.
[0] https://en.wikipedia.org/wiki/Hydroelectricity_in_the_United...
Why not inductive charging or any other wireless technology? Also it does not require a single entry point - do it in parallel.
Also when 1 minute is not possible, how about increasing the time?
Edit: in addition, charging entry does not have to be on the side, it can be on top or on bottom - we do not need any gravity assist.
Parallel charging is potentially the answer - but even with 10 cables, for a 100kWh battery, you're still talking.....600kW per cable? CCS goes only up to 200kW(and those are THICK cables), so if you increase the charging speed to 3 minutes then yes, you could do it with 10 cables. 6 minutes with 5 cables, 30 minutes with one cable.....and we're(almost) back to what existing technology already allows?
What about short range inductive charging from the bellow of the car (where the battery is)? With grid of 5x5 or 6x6 for example?
Inductive charging because it would be very difficult to have any kind of plug below the car because of the high corrosion risk.
Charger must align itself automatically to the right position and distance.
https://insideevs.com/photo/5439695/mine-smart-ferry-fast-ch...
I did find this using 13 kV: https://www.energytrend.com/news/20180904-12449.html
https://www.schleich.com/en/product/high-voltage-cables-en/
100 kV DC, outer diameter 14 mm
14mm is perhaps even smaller and lighter than needed for this application too - how might you expect diameter/weight to scale for cables over 100kV?
10kV is 5mm, 65kV is 10mm, so something like sqrt(V) + 4mm. I guess 500 kV would be around 30mm for each wire, which is starting to get unwieldy.
...in 2025 (from the article).
It doesn't say in the article, but I wonder if these batteries can charge 100 miles per 5 minutes for a larger range than current vehicles. I'd happily charge at 150kw instead of 300kw, if that meant that I could do so from 10-80 instead of 10-20.
Which makes this a ~25% improvement.
The "charge overnight" model is ideal for commutes within the EV range, but not for long road trips. This is a problem and we need solutions.
Solutions include:
- Fast charging: Yes, it is mimicking gas cars, but gas cars are great at that, so it is not a bad thing
- Huge batteries: The idea is to have enough range not to need en route recharging. Problem is, batteries are heavy and expensive
- An internal combustion engine: Purists don't like it, but it can be a good compromise for many people
- Battery swapping: it has been suggested, Tesla even did a demo, but it doesn't seem practical
If you don't consider it a problem because "EVs are different", then EVs will never replace gas cars. And replacing gas cars with EVs as much as possible is exactly what we want.
The problem is that most people use their car to commute and they also use that car for maybe 4 car trips per year. Somehow waiting 2 hours more per trip is completely unacceptable but causing pollution that makes people ill even when it is completely unnecessary is somehow very acceptable.
People will imagine impossible technology to save those 8 hours per year and then pretend that they deserve this impossible technology. Think about how impossible it is to solve climate change with CO2 polluting cars. Meanwhile waiting for your EV to charge up 4 times a year is the worst and climate change is considered the lesser evil.
Batteries that could be charged by "refueling" [1], or fuel cells that require hydrogen are a much more feasible solution and environmentally safe for the long term
[1] https://www.smithsonianmag.com/innovation/battery-recharges-...
Losing all that convenience, 2/3 of your energy, and having to build out a completely new fueling infrastructure to use hydrogen fuel cells just makes no sense.
Which can also be an obstacle of its own—something like 60% of homes in the UK only have on-street parking, making overnight charging difficult to say the least.
In Oslo, where a lot of parking is handled by the municipality, they've put up charging poles and charge a small fee for the electricity. That's about the hardest case, it's a PITA to dig up the street in a dense city to install these things.
My friend lives in an apartment complex with outdoor parking, where the parking is managed by the HOA. Owners/renters can pay to have a small charging outlet installed at their parking spot. Funny thing is these parking spots already had outlets for engine heaters (it can be hard to start ICE cars in winter), but I'm pretty sure they had to lay new wire for charging since the current can be higher. Same deal with our home. It's a garage, but managed by the HOA. They decided to renovate the fuse box and electric wiring to facility installing chargers, since wiring was old and needed to be renovated anyway. Owners pay for the charging box and installation. There's a small load balancer that insures that the chargers don't overload the main power supply to the garage.
It's a challenge, sure. But faaar from impossible. I get that the US has a problem with doing shared infrastructure in general. But I think this will solve itself once there's enough money to be made. Similar to how internet/cable is rolled out. Companies will offer the owners of the apartment complex to install the chargers for free, in exchange for charging a fee on the electricity sold to people charging with them.
I honestly, hand on heart, don't understand how anyone still believes this. Honestly. Hydrogen is a PAIN to work with. We don't have any elemental hydrogen on earth. Nearly 100% of hydrogen available in commercial supply comes from fossil fuel production and while it could still be produced by electrolysis it's a stupidly inefficient process, especially since the resulting gas then has to be compressed for transport. And most importantly, no one has answered a simple question - with hydrogen being the smallest element of all, it leaks out of any container you put it in, making it brittle as it does so. 70kg lead bottles only store 1L of hydrogen, and all of it naturally evaporates through the metal within few weeks. Woven carbon fibre tanks are better at this, but it still evaporates with time and the tanks are incredibly expensive to manufacture.
I'd argue it's not feasible at all. It's a pipe dream that people keep bringing up for some reason because it looks great on paper. In practice the production and transportation and then safe usage of hydrogen are significant obstacles, where batteries have none of them - the only advantage is the fueling speed, but even then I'm not so sure - have you seen videos of any commercial fueling stations for hydrogen? The Toyota Mirai with its tiny tank takes about 10 minutes to refuel since the process has to be done so carefully. Yes it's faster than electric charging, but the speeds we're seeing on some cars(Porsche Taycan, Tesla Model 3) are already crazy, like 60 miles of range added in 5 minutes crazy.
60 miles in 5 minutes is far slower than 400 miles in 5 minutes. Even better, you can consistently go from 0-100% and not 10-80% or whatever. It also scales to larger vehicles, something that simply won't work with batteries. Not unless you're consider elaborate solutions like overhead catenaries.
Large family vehicles on the other hand, there are a few hybrids that fit the bill but none of them are stand-out and the additional mechanical complexity is (rightfully) giving folks pause. The early prius for example got it right and was quite reliable, later iterations unfortunately have not lived up to the reputation it built. But then there's also rural car ownership where fewer, longer-range trips are the norm. Not much adoption to be seen there for very good reasons, neither the cars nor the charging infrastructure is suitable.
Depreciation is a kicker, also. Early adopters are finding that with the rapid progress on range/features and manufacturers chasing lower RRPs to get more adoption, when they come to trade up to something newer the value of their early purchases is lower than a similarly-aged ICE.
All of this is still good progress, but I think we're at least a decade if not several away from ICE being pushed into a niche. Plus without some breakthroughs in battery tech, there's only so far into the market things can go. Fortunately some promising stuff seems to be on the horizon i.e. solid state.
And as far as I'm concerned a Y is a large family vehicle. It's no Escalade, but it's larger than our small minivan. If you disagree, there are some large trucks and SUV's coming in 2021/2022.
Depreciation is a kicker all right, but in the other direction. All actively cooled electric cars (IOW everything except the Leaf) depreciate a lot slower than a gas car. And that's just going to accelerate. Imagine trying to sell a 2020 ICE car in 2030. 98% of 2020 cars are ICE, but in 2030 the majority of new car purchases are going to be electric. Buyers of used cars want basically the same thing as buyers of electric cars, so the small number of available electrics are going to be in high demand.
They aren't a tricky engineering problem to solve - but nobody is too worried about solving them right now because the people who maintain the grid and who have to deal with harmonic losses aren't the same people as those who design the charger.
It's not as bad as you might think because replacing old chargers is easier than replacing all EVs.