back to article Liquid electrocar batteries could be replaced at pumps

Remorseless German boffins have come up with a solution to long recharge times for electric vehicles. They propose the use of liquid-electrolyte batteries, so that a 'leccy car could have discharged electrolyte pumped out and replaced with fully-charged liquid at filling stations. The proposals come from the Fraunhofer …


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  1. Anonymous Coward
    Thumb Down

    How do you price it?

    If you pump out the old liquid how do you charge for the new? With petrol you pay for what you put in... if the tank was half full you only pay for half a tank (unless your an idiot and spill lots on the forecourt). What if the battery has half charge...

    Bearing in mind fuel cost (and recharges) relates to the energy used between recharges will they just charge you full whack even for a 'top up'? £50 for a 'tank' whatever mileage you did? Nice idea, but seems impractical in the real world.

    Turn lecky (from nuclear/fusion asap) into petrol & stop wasting time inventing new e-cars.

  2. Balefire
    Black Helicopters

    The final paragraph

    The final paragraph may well be the most prophetic I have ever read in el Reg. Far too often superior technology is made by the smaller, more agile developers/inventors, only to crowded out of the market by the crap tech big companies push with their marketing, lobbying clout.

    Either that or bought out and buried.

  3. Eddie Edwards

    Better vs Worse

    "there are dozens of examples from the history of technology to show that better doesn't always win"

    There are plenty of people ready to say "A is better than B" as if A and B were things with only one dimension of variation, and plenty of history to show that they're wrong, but apparently we only learn that "better doesn't always win", not that the very concept of "better" is inapplicable in the real world where every object has multiple facets, all of which apply simultaneously.

    Technical merits have been proven time and time again to be the *least* important predictor of success. Especially when the relative merits are at marginal.

    Two different types of battery with broadly comparable specifications are never going to rise above each other on technical merit. Network effects will always dominate when selecting between two broadly similar choices - ultimately you buy what everyone else bought. Given that Li-Ion is already in use everywhere I'd argue that any contender which doesn't offer more life than Li-Ion is already dead.

    It's all irrelevant anyway. Electric cars won't shift in quantity until we move to a battery tech that has enough capacity to do the job, and that means actually pushing the specification envelope outwards, not coming up with a niche benefit at the same spec.

  4. Parax


    A Real Solution (Pun intended) to the battery problem!

  5. G R Goslin

    nothing new

    There's nothing new in the redox battery, with a liquid electrolyte. An American company was toying with the idea for peak lopping, and that's real power, over fifty years ago. The electrolyte in this case was an aqueous solution of chromium trioxide. It's really the best solution for electric vehicles.

    The main snag about battery cars, the long re-charge time, is not diminished by having quick charge batteries, it's merely transferred to the problem of the sheer amount of power that has to be transferred to the vehicles batteries. We're talking megawatts. here. The supply companies are not too keen on rapidly changing loads in this power range. Aside from the problem of disposing of the energy losses involved in the AC to DC and voltage conversions required.

  6. Filippo Silver badge

    More alternatives is always good

    Regardless of whether this solution will have success or not, it's good to see that scientists are still looking for new ways to deal with the battery problem. Noone ever found the best solution to a problem by sticking with the first one that was good enough.

    This one may eventually lose out to these lithium titanate batteries - or it may turn out that li-ti batteries have other serious problems. It's good to explore other venues.

  7. Grease Monkey Silver badge

    More like it...

    This is more like it. Somebody is starting to think about this properly.

    The problem with fast recharge batteries is current. There is no way to avoid that, if you need to stick in 100KWh of charge in in ten minutes than you're going to need either very high voltages to get the current down or very high current. The voltage is dictated by the battery, since you don't want to be carrying a big heavy transformer around with you, so you're stuck with high current.

    There are two major issues with massive current outputs the most commonly discussed one is the weight of the cables. The second and more important is the infrastructure needed to deliver that power to the cars. A charging station might need to be capable of giving a couple of dozen cars a fast charge at the same time, imagine the feed you would need to the station to achieve that. Of course our current infrastructure is simply not able to deal with such massive bursts of demand. One petrol station owner was telling me that he does the vast majority of his business between about 5pm & 7pm. If that was all electric charging it would make the surge in demand at the end of Coronation Street look tiny.

    We're already being told our electric supply will not meet demand in a few years. How much will loads of fast charge EV's hasten that? However filling stations being able to recharge pump juice over night when demand is low would be an ideal solution. It would give all those nuclear power stations something to do in the wee small hours.

  8. Anonymous John

    @ How do you price it?

    You'd have the same problem if garages offered a battery swap too.

    I imagine it would be possible to measure the charge of the liquid being removed, and adjust the price charged for filling up.

    Presumably the garage would recharge the liquid then resell it.

  9. JassMan Silver badge

    @How do you price it?

    When they empty the old juice before putting in the new, they put it back into an on site battery for recharging, and check the volts before the cycle starts. This gives a reading of how much charge is left. A computer can then easily work out how much charge you have used times the volume of juice and Bob is someones uncle.

    Battery technology is not they way to go however. There are much more exciting developments in Ultracaps just around the corner. These have the advantage that ALL the power from regenerative braking can be put back in the can. - Unlike battery technology where recharge rates are so slow that they will not accept the energy fast enough, even with Li-Ion.

  10. Bilgepipe


    As long as they pick an approach that is used consistently - I don't want to roll into a fuel station only to hear "sorry mate, we don't do those batteries..."

  11. TeeCee Gold badge

    Re: How do you price it?

    I suppose that you could have a Redox "tank" and a small, secondary Li-ion or similar battery charged off the Redox supply (if necessary) so that when your Redox is fully depleted you have 20-odd miles of "reserve" to get to the nearest petrol station.

    Actually I think the biggest problem here is twofold in that a) you need a take out / put in system rather than a simple fillup mechanism and, more importantly, b) that I'll bet that the Redox electrolyte, both depleted and charged, ain't exactly user friendly for liquid handling purposes....

  12. Eponymous Cowherd


    If this works it would make electric cars as convenient as petrol / diesel models. There are a number of problems to overcome. How, as Chris Morely asks, do you determine the cost of a recharge? I assume that it will be possible to pass the out-flowing electrolyte through a sampling cell in the pump to determine its "charge" and combine this with the actual volume to be replaced (different cars will have different capacities and *all* the electrolyte will need replacing irrespective of the remaining charge) to calculate the cost.

    Another problem would be how to recharge the electrolyte given that it will be extracted from different vehicles in different states of charge. Can it all be mixed together? I assume there will need to be (at least) 3 forecourt "tanks". One to receive discharged electrolyte, one to hold electrolyte being charged and one to hold fully charged electrolyte for delivery. These could be rotated as each batch is charged.

    The problem with the li-titanate "fast charge" is that, irrespective of the ability of the battery to *absorb* the charge, the "pump" must be able to deliver it, and safely. Very high currents and very high voltages in the hands of Joe Sixpack......?

  13. Matthew 25

    How about Hydrogen fuel cells?

    Fill tank with hydrogen....Drive 250 miles emitting nothing but water....Pull in and fill up again.

    Sounds like current motoring but without the emissions. Honda already do this see

  14. Anonymous Coward

    The supply companies are not too keen on rapidly changing loads in this power range.

    Hence a service station constantly charging a tank full of electrolyte,

    rather than switching on and off every time you get home go out..

  15. The First Dave


    Enough pissing around with Battery Tech - and put a bit more effort into synthesizing real fuels, whether that be H2, Petrol, Ethanol or similar. there is a good reason why battery cars never took off a hundred years ago, despite being safer than internal combustion...

  16. Anonymous Coward


    Hydrogen powered cars (hydrogen extracted from water using energy from non fossil fuel source) with ultracaps/batterys/dynamo system for the regenerative braking system. Use the fossil fuels to make plastics that we can recycle for the equipment and vehicles etc and for where alternatives yet to exist.

    All possible now, so lets get going.

    The main reason companies are looking to find and promote alternative methods is for the patents and money they can bring in.

  17. Graham Bartlett


    Yeah, something like that'd work. Actually there's an even easier way, if I remember my chemistry lessons, which is ph-testing the solution. The more charge left, the more acidic it is.

    That replacing-the-electrolyte idea really does seem like the way to go. The electrolyte might not be very user-friendly stuff, but it's not a major engineering step to have hoses and tanks which seal when refilling - it's mandatory for fuelling F1 cars, for example. And being able to spread the electrical load over the day will make it much better from the electricity company's PoV. With a bit of infrastructure and a suitable reduction in rates for the places doing it, they could even use the filling stations for load-balancing across the national grid.

    Ultracaps aren't really a solution to the battery-charging problem - you still have the problem of needing megawatts on tap to do the charging. But they're a good solution to the problem of getting the most out of your regen braking. It's likely that a seriously efficient electric car would use a smallish ultracap as a reservoir to buffer rapid changes of current, whilst also using a large battery as the major energy store.

  18. scatter

    "Turn lecky..."

    "Turn lecky (from nuclear/fusion asap) into petrol & stop wasting time inventing new e-cars."

    Eh? Convert it into petrol and throw 70% of its energy content away as heat?

  19. Adam 10

    Wait a tick...

    So, you have to stop, have a whole bunch of toxic nasties pumped OUT of the car, then pump a fresh batch of toxic nasties INTO the car.

    Can someone explain to me how this is better than pumping in some form of benign liquid hydrocarbon (ethanol?) to be burned in an ICE or oxidised in a fuel cell?

    They should focus more effort into renewable energy -> CO2 cracking -> liquid hydrocarbon technology. It's been demonstrated with solar power so far, surely wind/tidal systems could be developed.

  20. Charles 9 Silver badge


    ...if they can really get the problem of capacity with the electrolyte licked, then this sounds interesting. Not only that, can this kind of battery tech scale (as in use a bigger battery case with more electrolyte for longer range)? We'd need a few more details, but this sounds like the most KISSed solution yet.

    I have qualms about hydrogen since practical hydrogen usage would require a very-high-pressure tank--think leaks. Not to mention any hydrogen that does leak can become very reactive.

  21. Iggle Piggle

    Won't you feel a little dirty...

    .. filling up your shiny new Skoda having just seen some filthy fifteen year old Porsche pulling away from the same pump and knowing that it has just dumped it's used juice into the machine you are now using.

    Or to put it another way, how will they enforce quality control. I bet someone will find a way to fob off the garage with something that isn't up to standard.

  22. Matt Bucknall

    @The supply companies are not too keen on rapidly changing loads in this power range.

    So, buffer the transients in load with flywheel energy storage. I think the difference between peak power and average power demand will be fairly signifcant. Most refueling stations aren't going to be open, continously recharging cars 24 hours a day, so they can build up their energy reserves at night time and in-between car recharges.

  23. BristolBachelor Gold badge

    Re: How do you price it?

    A redox battery normally has two tanks, one for "charged" electrolyte and one for "discharged". The fluid is only pumped through once, at the rate the energy is used. Think of it like a fuel cell, where hydrogen & oxygen go in one side and water comes out the other.

    In fact in some redox situations, the "battery" used to charge the fluid is a different one including different voltage, to the one used to discharge the fluid.

    The only problem in a car is that you don't want twice the volume. Maybe they can work on a single tank with a membraine or internal sliding piston separating the new and used electrolyte. I think I will patent the latter, with a motor to drive the piston to pump the fluid from the new to the used side - oh making it public just put the kybosh on that!

    This is the ideal type of battery where the instantaneous power required is low compared to the total energy storage requirement. The active part is sized for the power requirement; the tanks are sized for the range. You can double the range by simply increasing the volume of the cheap tank part.

  24. Anonymous Coward


    Aside from your made up efficiency figure, yes. Petrol is practical. Petrol is safe (high auto ignition temperature). Petrol does not explode if you drop a spanner across its terminals - or shoot it. Petrol is non-corrosive and evaporates if spilled. While some petrol evaporates from a tank (breather) while parked it doesn't internally discharge meaning you car works when you land at the airport after a few weeks away.

    While a single expansion Otto cycle is ~35% efficient we have now had turbos for ~100 yrs. And yes you can extract a lot of power from the "heat" in the exhaust. Total efficiencies of electrical systems are poor... 98%s bandied around are lies... rewound racing alternators are ~50% efficient... current through wires & battery cells causes heating on both discharge & charge... DC/DC converters might _peak_ efficiency at 90-95%. Electric = magic. Nope.

    If a front driveshaft pops out & pierces the underside of the car would you really prefer it to pierce batteries instead of a petrol tank?

    Lastly, you've just got home from work. You get a phone call, a close beloved family member who lives 200 miles away has gone to hospital and is in a serious way. Do you...

    a) Take the petrol car, fill it with petrol and drive straight there

    b) Plug in your electric eco-toaster. Wait 12 hours for it to charge off your house wiring. Drive 150 miles and run out of juice... get a taxi for the last 50 miles

    Flame? Why? Petrol rules!

  25. Sean Timarco Baggaley

    Re. Hydrogen.

    One word: "Hindenburg".

    H2 has terrible PR. This isn't likely to change overnight, even though LPG distribution has had to solve most of the same problems. (Including pumping a liquified gas into a car under high pressure.)

    Another issue is that H2 isn't that cheap to make. Wind farms and tidal barrages are some of the most expensive sources of electricity available thanks to their intermittent nature and high capital construction and maintenance costs.

    Iceland generates more electricity than it can possibly use using geothermal; France is almost totally reliant on nuclear energy, while Switzerland uses mainly hydroelectric generation. These countries may be able to standardise on energy-expensive hydrogen cracking, but few others can justify it. What's the point in burning hydrocarbons to produce the electricity to crack hydrogen when you could just burn those hydrocarbons in the car directly?

    The problem, IMHO, is this fixation with having all cars carry their own power generation plant around with them. I don't think it's necessary. The technology to transmit power to vehicles has been around for over a century, with more recent innovations including inducted power which don't even require a physical connection. ( — a technology which would work just fine with vehicles other than trams.)

    Very few cars ever venture off-road, so why not let our roads provide the electricity? Problem solved.

  26. Pete "oranges" B.
    Thumb Up

    @How do you price it?

    You could use multiple cells in a serial failover system. For instance, the car could have four smaller cells of the same type but only use one or two at any given time, thus allowing 2/4 - 3/4 of the cells to be fully discharged during continuous operation and drained/refilled at the user's convenience.

    This is of course dependent on favorable weight/power ratios and the self discharge rate of the cells, among other things.

  27. Anonymous Coward
    Anonymous Coward


    Hydrogen as a fuel has some obvious problems.

    The most common way to make it is from water, but current tech means you need clean water. You can't just use something from the nearest river as it would ruin your hydrogen plant. So you need to make clean water in order to make hydrogen. Clean water is already a precious resource. Would you rather drink it or power your car with it?

    Secondly you need electricity to make the hydrogen. So you still need to generate as much electricity as you would with battery powered EVs.

    Thirdly water emissions are not necessarilly good. If it's vapour then it's a greenhouse gas, and stops being a greenhouse gas when it falls as rain. Climate change anybody? If it's liquid then you don't want it spilling on the road in the middle of winter do you? So the best bet would be to store the water emissions in a tank and use it to make your next batch of hydrogen. So you need space for the tank and your car will get heavier the further you drive.

    Finally Hydrogen is famously a bit awkward to store and transport. I think Joe Public might start getting a bit twitchy when a hydrogen storage facility moves in next door. Especially if he's ever heard of the Hindenberg.

    The way the popular meeja (like Top Gear) present it is: You just take the hydrogen out of water then bung it in your car. Whizz. It's a bit more complicated than that.

    None of the problems are insurmountable, but I would say that from a point of view of the tech now available to put an infrastructure in place redox batteries have the edge at the moment. Fuel cells are 170 years old I'm sure they'll get their turn soon enough.

  28. MinionZero

    I strongly suspect electric cars will win for many reasons in the end...

    @The First Dave: “Enough pissing around with Battery Tech”

    ... And while your at it, stop trying to sail them ships to them Americas, they will never be cost effective or practical. They will fall off the edge of the world. So millions of people won't choose to deal with and go to the Americas. Nope it will never catch on. ;)

    "there is a good reason why battery cars never took off a hundred years ago, despite being safer than internal combustion..."

    Yes several reasons. Poor weak electric motors, poor low capacity batteries, poor and heavy car materials, poor national grid ... oh there wasn't even a national grid back then! (It took until 1926 for William Weir's committee to sort out the mess. Before that time different parts of the country had different supply voltages and even different types of plugs etc.. it was a total mess).

    Meanwhile now and in the decades to come, its getting a lot better. For example,

    (1) Electric motors are now vastly stronger (Try looking up some of the insanely strong small magnets around these days) – Myth Busters sometimes uses them (they call them the Magnetic Hockey Pucks Of Death, which isn't far from the truth if you are holding one that you suddenly move near another one thats free to suddenly fly at you. They are getting scary how powerful they are now).

    (2) Batteries are starting to finally improve - not perfect but getting much better capacities and continuing to improve.

    (3) Light weight car materials have vast potential to be improved upon. For example carbon is very likely to become the manufacturing material of the 21st century and not just carbon fiber, in time I mean also carbon nanotube based materials. Nanotube manufacturing capacity is going to become main stream and rapidly increasing even now, so give these materials another 15 years for the industry to grow more (and so they also become cheaper). Imagine a car even just a 1/5th of the weight of a present day car, that is also much stronger than steel. (5 times lighter is easy for carbon nanotubes). With a difference like that, the car will be able to go a lot further even with existing batteries and motors.

    All these factors are improving all the time. The lighter the cars become and the better batteries and motors become, the more electric cars become ever more practical as their power to weight ratio continues to get ever better. At some point their power to weight ratio will make them very attractive to the mass market *average car owner*. (It probably won't produce the fastest cars ever see (any time soon), but then the best technology doesn't always win ;)

    Also with electric everything in the car, there will be far less mechanical parts to go wrong, especially in the engines. That factor alone will make electric cars very appealing to many people who don't want to spend their weekend under the car bonnet, covered in grease and stuck in the rain outside their house. Plus fewer engine parts means it will also be cheaper to build the electric cars.

    I would however just say that I'm not convinced about changing electrolytes is that safe though, especially when its changed by millions of non-technical people every day. If I splash a bit of petrol on my hand no problem. But some of the chemicals in electrolytes are far worse on humans than petrol (unless you also have a lit match ;) ... which doesn't happen that often ;) ... but anyway, there are multiple factors converging that all make the electric car ever more appealing to the mass market. So it doesn't matter if its another 10 years from now or another 20 years. Electric cars are becoming ever more appealing.

  29. Anonymous Coward

    @Shaun Wilde

    The single biggest problem with "hydrogen" is that it is made, when made in industrial quantities, but stripping hydrogen off methane. Hence the reason "the hydrogen economy" is estimated to be more environmentally damaging that directly burning the methane or other fossil fuels, and is classic green washing.

  30. Anonymous Coward
    Anonymous Coward

    @ Sean Timarco Baggaley

    'Iceland generates more electricity than it can possibly use using geothermal;'

    Actually most Icelandic power comes from hydro power; only about 25% is geothermal. But you're right, they have stupid amounts of power to tap and it is insanely cheap (the average Reykjaviker pays about 1/4 as much as a Britain for all the electricity and hot water they can possibly use).

    The Icelandic government in association with Shell and Norsk Hydro already done extensive trials of running buses on hydrogen in Reykjavik, but have decided not to proceed further. Instead they are switching to biogas from sewage - you can recognise the biogas buses by their green roofs. The hydrogen filling station is still visible on Miklabraut as you leave the city for Hveragerði (if you're going that way, do stop off en-route at the entirely awesome geothermal plant at Hellisheiðivirkjun - it's like an Apple store has been dropped on the Moon)

    There were plans to start experimenting with converting the Icelandic fishing fleet to hydrogen, but AFAIK they have been put on hold thanks to a few Icelandic billionaires running off with everyone's money.

    A more economic prospect for Iceland would be to string a DC cable to the UK and pump their cheap electricity into the National Grid. The current plan by the main power company is to start offering cheap power to companies wanting to run server farms and manufacture solar silicon and to diversify away from the country's dependence on aluminium smelting which has got a bad environmental reputation of late.

  31. Anonymous Coward
    Thumb Down

    No electricity ... no electric cars.

    The first part of analysing the viability of any system is to test that it scales to fit the target market.

    As others have pointed out; the first problem taht comes to mind is in getting the electricity to the point where the battery is charged; even if it's just the electrolyte.

    Looking at the number of vehicles served by filling stations in a day would be a starting point for estimating the number of electric cars that will be visiting an e-station: About 4 to 10 times as many as for "normal" cars because e-vehicle range is limited.

    Giant vats of electrolyte, continously being recharged might make for good science fiction, but they're not going to work well in practice. In practice, people would want to pay for fully-charged electrolyte; and that means several vats of the stuff that'd need to be cycled continuously. Then there's the credit thatthey'd expect for the residual charge in the electrolyte that they're bringing to the station. Keep in mind that stations will have to cope with possible thousands of vehicles a day.

    Other parts of the battery - the electrodes, as well as the exchange process, can contaminate electrolyte, contamination thatcan probbaly not be filtered completely. Degradation is inevitable.

    Handling the electrolytes safely would be a nightmare. Imagine pumping 10 gallons of sulphuric acid instead of petrol or diesel. Electrolytes are corrosive. Some react violently when exposed to air.

    And how much energy are we putting in the vehicle? How much would the process of putting it in there cost?

  32. Anonymous Coward

    To those people advocating Hydrogen...

    I suggest you read the cold maths of efficiency and KwH/Km here (as previously advocated by El Reg):

    Hydrogen is not the best option, even with energy reclamation systems (many of which can be used with other systems anyway).

    To Quote:

    I think hydrogen is a hyped-up bandwagon. I’ll be delighted to be proved wrong, but I don’t see how hydrogen is going to help us with our energy problems. Hydrogen is not a miraculous source of energy; it’s just an energy carrier, like a rechargeable battery. And it is a rather inefficient energy carrier, with a whole bunch of practical defects.

    Here are some numbers.

    In the CUTE (Clean Urban Transport for Europe) project, which was intended to demonstrate the feasibility and reliability of fuelcell buses and hydrogen technology, fuelling the hydrogen buses required between 80% and 200% more energy than the baseline diesel bus.

    Fuelling the Hydrogen 7, the hydrogen-powered car made by BMW, requires 254 kWh per 100 km – 220% more energy than an average European car.

    Hydrogen advocates may say “the BMW Hydrogen 7 is just an early prototype, and it’s a luxury car with lots of muscle – the technology is going to get more efficient.” Well, I hope so, because it has a lot of catching up to do. The Tesla Roadster (figure 20.22) is an early prototype too, and It’s also a luxury car with lots of muscle. And it’s more than ten times more energy-efficient than the Hydrogen 7! Feel free to put your money on the hydrogen horse if you want, and if it wins in the end, fine. But it seems daft to back the horse that’s so far behind in the race. Just look at figure 20.23 – if I hadn’t squished the top of the vertical axis, the hydrogen car would not have fitted on the page!

    Yes, the Honda fuel-cell car, the FCX Clarity, does better – it rolls

    in at 69 kWh per 100 km – but my prediction is that after all the “zero-

    emissions” trumpeting is over, we’ll find that hydrogen cars use just as

    much energy as the average fossil car of today.

  33. Onionman

    One reason this might succeed

    This solution will allow Gordon to take his cut. Anything that allows you to charge up at home is tough to tax without introducing road charging. This would be the same as the current fuel infrastructure, so the Gubment could take their usual pound of flesh.


  34. Chris Miller

    @Sean (13:20)

    Induction is a nice idea for city centres, where battery cars are already a good solution, but I can't see it covering every road in the country. The problem with Hydrogen is not simply bad PR, it's threefold:

    (a) expensive (in environmental terms) to make - already commented on above.

    (b) storage - two options, cryogenic or ultra high pressure (or a tank three times the size of the vehicle :) both of which are subject to significant, unavoidable leakage. This gives rise to two further issues:

    (c) park your car at the airport and come back two weeks later to find the tank empty (similar problem with batteries) or (worse) leave it in the garage for a couple of days, come down in the morning, flick on the (low-energy) light, generate a small spark and ... instant Hindenburg in the comfort of your own home.

  35. YumDogfood

    @AC re: Thirdly water emissions are not necessarilly good. ..

    Wow, had a reality dysfunction check there. I could be a real anti-ecowarrior sloshing my bottle of pop all over the roads.

    The problem with all these solutions is that the end result is still a car, or even worse, a truck. A vast disaster to force a cultural shift may be required to rethink our whole idea of transport, we are not going to get off our collective arses elsewise. Til then we will be throwing resources at trying to solve problems arising from19th century tech thinking.

  36. G Fan

    @How about Hydrogen fuel cells?

    "Fill tank with hydrogen....Drive 250 miles emitting nothing but water....Pull in and fill up again."

    Lovely, except hydrogen is a pain in the arse to handle and store, will leak at the slightest provocation (including /through/ the metal for a lot of common construction metals) and once leaked, needs very little energy to set it burning.

    I'm quite happy with the idea that a cylinder could survive a reasonably high-velocity impact unscathed: enough LPG-powered cars have done so. I'm just less happy with the idea of coming back from holiday after 2 weeks to find the fuel tank empty and the passenger compartment full with invisible go-go-juice.

  37. Alfonso Vespucci

    "even the electric car itself has rivals "

    Horse, meet cart.

  38. 4HiMarks

    What about spills?

    How toxic is this stuff? If two of these cars crash into each other and a tank ruptures, spilling electrolyte all over, how bad is it going to be to clean up? Who pays for the cleanup?

  39. Noah Monsey

    Hydrogen Fuel cells are here now.

    Hydrogen fuel cells are already here now.

    Several automobile companies have practical hydrogen vehicles in use now.

    The cost of hydrogen vehicles will come down quickly as the manufacturers start to ramp up production volumnes. The car companies have had years of experience testing and using several generations of vehicles and fuel cell stacks. Over the next couple over years several companies will introduce production FCV (Fuel Cell Vehicles). Take a look at and to read current information about fuel cells. There seems to be a lot of skeptics posting comments based on out of date information. Companies like Honda, Toyota, General Motors and Ford would not have Fuel Cells vehicles if they where not practical.

  40. Grease Monkey Silver badge


    Yes Iceland gets a lot of electricity and heat from geothermal energy, but it's a long way from being free. Even in Iceleand where geothermal energy is never far from the surface the plant still costs a lot to manufacture, install and maintain. Then there's the distribution network (for electricity or heat).

    Infrastructure costs. It costs a lot.

    How much of you electricity bill do you suppose comes from cost of the coal, gas or uranium? Most of it comes from the cost of the plant and infrastructure and the wage bill of the people that make it work.

    In exactly the same way hydro, wind and tidal power won't be free by the time they reach your home.

    The trouble with building a hydro electric dam is that you need geography on your side, so it will probably be a long way from the major cities where most of the electricity is used. Windfarms? Well they need to be somewhere windy, so well away from things like cities that interfere with the flow of wind. And people don't seem to like them near their homes. Nuclear plants? Well nobody wants one of those on their doorstep do they. So they end up being built is as remote a location as possible, preferably in what is already a safe seat for the opposition (what me? cynical?). All these things mean more expensive infrastructure to deliver the electricity to your home.

    So don't get carried away with that green ideal that "sustainable" power is somehow cheaper. It ain't.

    Here's an unrelated thought: What would happen if people's electricity bills were calculated based on the cost of getting electricity to their homes?

  41. Robert Carnegie Silver badge

    This very nearly is a fuel cell.

    This very nearly is a fuel cell. You pour the magic juice in and electricity comes out. That's the same as what a fuel cell does.

    Personally I'd go for green methane or bicycles. Hydrogen is too hard to handle. It's tiny molecules, it leaks. On the other hand, a lighter-than-air vehicle lifted as well as powered by hydrogen would be ace. I'm a bit not good with height though. A lot actually.

    Delivering a supply of electrolyte presents similar problems to running a chip shop, plus if you're extracting used electrolyte from the car, how do you know it's good value stuff and not watered down? As with a battery physically removed from a car by robotic equivalent of block and tackle, the unit might have to be a kind of security vault with its own computer and tampering alarm.

    Power storage on site can be done, however, with a big heavy scary capacitor, or a bank of them. Or put the car chae!rge station next to the local electricity substation.

    I also still want to see robot cars capable of at least getting themselves charged or filled or whatever without our participation. And also parking themselves at the supermarket. Just going away when not wanted. In fact a device already exists that meets many of my expectations for a car. It's called a "taxi". Only if you want to visit your sister a hundred miles away then the taxi probably won't want to take you. But it would if it was a robot. Perhaps in the future we will more often hire robot cars for long journeys instead of owning them.

    I also want a robot at work that I can operate by remote control from home, so I don't have to go. But if the robot is too good then my employer may decide they don't need me. I can imagine my boss being confused about the system anyway. Although he spends a lot of his day, relatively, commuting in a non-robot car, so it should be just the thing for him too.

  42. Paul 129
    Thumb Up

    Tech useful in household systems

    The development of a commercial flow battery setup, must have merit for the big petroleum distributors. So the distribution wouldn't be that much of an issue IMHO. If it ever did take off, it'd be dammed handy for domestic purposes too. If it was affordable/obtainable I would be sourcing a flow battery for a domestic solar setup allready. I have enough land, but not the available cash

  43. JeanP

    A little on the safety of the redox solution

    "Chromium trioxide is highly toxic, corrosive, and carcinogenic.[4] It is the main example of the environmental hazard known as "hexavalent chromium." The related chromium(III) derivatives are not particularly dangerous, thus reductants are used to destroy chromium(VI) samples. Chromium trioxide, being a powerful oxidizer, will ignite some organic materials (such as ethanol) on contact." (wiki/msds)

    Not sure if this is the specific redox formulation they have in mind, but it is an example. Guessing a biofuel - redox hybrid may be a little risky.

  44. Hayden Clark Silver badge
    Thumb Down

    NiMH is the way to go


    That's why everybody is pissing about with dangerous, expensive Lithium cells for e-cars. We should have been driving about in electric cars for years by now.

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