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[Richard230]

There isn't as much need to standardize lead-acid starter batteries, though.  The most you have to deal with it is to buy a new one every few years, so if you have to order the right type or go to your dealer to make sure you get a compatible model then it isn't that much of a hassle.

If people were to buy into battery swaps for EVs, though, there would be much higher motivation to standardize.

My issue with battery swaps is that the conditions of the batteries would be highly variable.  If you stop for a battery swap in a low-traffic area (i.e. "the sticks"), then you might get one with low range due to having been left on a charger too long (or worse, not having been kept reasonably well charged).  And, that would happen to you possibly in a situation when you really needed the range...

Kind of sounds like going to a gas station and getting a tank full of "bad gas", leading to poor combustion in your IC motor.   

[ZeroSinMA]

There isn't as much need to standardize lead-acid starter batteries, though.  The most you have to deal with it is to buy a new one every few years, so if you have to order the right type or go to your dealer to make sure you get a compatible model then it isn't that much of a hassle.

If people were to buy into battery swaps for EVs, though, there would be much higher motivation to standardize.

My issue with battery swaps is that the conditions of the batteries would be highly variable.  If you stop for a battery swap in a low-traffic area (i.e. "the sticks"), then you might get one with low range due to having been left on a charger too long (or worse, not having been kept reasonably well charged).  And, that would happen to you possibly in a situation when you really needed the range...

Kind of sounds like going to a gas station and getting a tank full of "bad gas", leading to poor combustion in your IC motor.   

There is a famous company called Better Place that tried this for the auto EV market.

http://green.autoblog.com/2012/12/02/better-place-battery-swapping-coda-taxis-california-2014/

So far the swappable battery concept has only worked for limited-range fleets ala CNG and other alt fuels. And it ain't cheap; Better Place has raised $750 million to date and lost $400 million.

The concept has the same chicken & egg problem that dogs alt fuel adoption. Service station owners aren't going to invest $200,000+ per station for Better Place when there are virtually no cars that use the swappable batteries and manufacturers aren't going to invest to use the batteries if there are not enough stations to keep a vehicle fueled. The EV problem is even worse because battery tech and battery specific power management is a key differentiator among competing EV makers, so they have no motive to adopt a single battery solution. It's not going to happen. Instead, battery technology will improve recharge times.

[Richard230]

I agree.  Once you can recharge your vehicle in 5 minutes (which I believe will eventually happen) and every gas station (well maybe not the ones owned by the oil companies) has several quick charge "pumps", where you can plug in while you are visiting the convenience store, refueling your batteries will be just a convenient as refueling your IC car is now.  Plus, I'll bet that the cost to install and operate fast charging stations won't be much more expensive than doing so for gasoline pumps - with a lot less regulatory, pollution and equipment replacement hoops to jump through every couple of years. (My local gas stations seem to always be tearing out their leaky tanks and replacing them with new double and triple-wall tanks, which still leak after a while, while installing new and expensive pollution control and safety devices.  That has got to be pretty expensive.)  I think EV charging will eventually make economic and business sense. It is just going to take time and more chickens and eggs.

[trikester]

As someone earlier stated on this thread, the future probably lies in the fluid flow battery technology. Fluid flow battery technology has been around for quite some time but very recent advances in that field, and with lithium based tech, give a lot of promise for the future.

With a fluid flow battery, the rider would pull into a refueling station and the pump would pull out the discharged fluid from the battery and pump in fully charged fluid. It shouldn't take much longer than filling an empty gas tank. The used fluid is then sent to the charger where it is recharged for the next user. The same fluid is used over and over again since the charge is carried in the fluid instead of the hard parts of the battery. However, the battery can also be recharged in the normal manner, without removing the fluid, when the bike is parked and plugged in to a power source. Can you say "win, win"?

Most of the research in this technology, in the past, has gone into making very large fluid flow batteries for massive solar and wind power storage. However, with the recent advances in smaller and lighter fluid flow battery technologies, the uses for vehicles are looking brighter.

Trikester

[NoiseBoy]

Surely half the point of electric is to move away from reliance on expensive fluid (aka gas) that is pumped around and carried by tankers and sold at extortionate prices.  I hope that the tech doesn't catch on but that fast charging emerges as the winner.

[trikester]

Please read it again!

The fluid comes from the factory, in the battery just like the batteries we use now. After it is discharged it is removed and pre-charged fluid is pumped in. The fluid that has been discharged and removed from the battery is then recharged at the same location and can be put into the next battery.

There is no trucking around of fluid! It is just moved from one battery to another after being put on the charger and recharged. The fluid carries the charge, as I said, and is used over and over again. There would be no need for it to ever leave the fueling station. Sure, maybe to get started, a new station might need an initial supply brought in by truck, but after that it is just a matter of supplying electricity to recharge the fluid and then recycling the fluid through other rider's batteries.

I see no reason why anyone would not want this technology to "take off". It seems like a win, win, as I said. No waste, nothing consumed (after initial manufacture) except electrical power, just as now with the batteries we are presently using, but a heck of a lot faster to get back on the road again.

Trikester

[NoiseBoy]

Logistics aren't that simple.  People aren't going to 'refuel' in the same place every time at regular intervals, which means you need a stock of electrolyte and any stock needs to be moved around to where it is required.  It will have to be trucked or piped.  Battery swap is the same deal.

Also, anything that is moved regularly from one container to another no matter how careful you are will become contaminated so at some point it will have to be renewed.  Roll in the trucks.

[trikester]

Well, I guess you just can't please everybody.

[machone]

It's a really interesting possibility. I wonder if there would actually be a redistribution of fluid over time ie people 'moving' the fluid away from the garage of origin, or whether something like the banking system of account settling could be used. Each garage would have to have some sort of coding in the fluid itself to identify where it came from.

[Richard230]

It's a really interesting possibility. I wonder if there would actually be a redistribution of fluid over time ie people 'moving' the fluid away from the garage of origin, or whether something like the banking system of account settling could be used. Each garage would have to have some sort of coding in the fluid itself to identify where it came from.

It seems to me like you could use a "U-haul truck rental system" (I have no idea what that system is) to keep track of the battery fluid location and where replacement fluid might be needed.

[protomech]

It probably would be metered so that you get exactly however much you pump out. Pump 25L out, pump 25L in. If there is a shift, it surely would be slow.

[trikester]

One thing I didn't mention in my reply to NoiseBoy was the problem with ultra fast recharging of batteries (without the fluid flow system). Many times I will pull into a gas station where there are six or eight cars refueling. If those were electric vehicles with access to some future very fast charge method, of say a few minutes to recharge, it would put a massive surge load on the electrical supply to the service station. If the answer becomes very fast electrical recharging of batteries then some method of on-site storing of power to supply big surges and then spreading out the load, over time, on the supply network would need to be developed. Maybe a big flywheel/generator combination. That's something the fluid flow method would do by its very nature because the spent fluid would not have to be fast charged. It could be recharged at a slower pace as long as there was enough charged fluid on hand to satisfy the demand.

If it gets to where there are trucks hauling around fluid, because of unequal usage at service stations, then let's hope those trucks are electric and running on fluid flow batteries also.

Trikester

[CliC]

I haven't read up on fluid-flow tech yet, but one potential issue that comes to mind w.r.t. EVs is that you aren't refilling one large tank, but possibly hundreds of tiny ones. How do you make sure all those cells get emptied and filled? And what about hose routing, especially when it can be a challenge to get even the BMS wiring cleanly into an EV? Exchangeable electrolyte will likely take a significant rethinking of how batteries are done in EVs. But hey, if it works...

I also agree with an earlier comment that 5-minute charging is unlikely to be common anytime soon. To fully recharge my 10 kWh bike pack in 5 minutes, aside from needing a 12C charge rate battery, I need 120 kW of power. And that's for a small bike pack. Think of 2-8x that for a car, times 10-20 simultaneously for an average corner station, and you're looking at multi-megawatt industrial-level electrical service.

[ZeroSinMA]

Surely half the point of electric is to move away from reliance on expensive fluid (aka gas) that is pumped around and carried by tankers and sold at extortionate prices.  I hope that the tech doesn't catch on but that fast charging emerges as the winner.

Gasoline? Sold at extortionate prices? Are you kidding?

Friends in the energy industry educated me about gasoline and diesel. There is no profit in it for retailers. All of the profit is in the stuff they sell in the convenience store that you buy while you're at the station to buy fuel.



- Refined from finite resource: crude oil
- Pumped, piped, shipped, stored, etc.
- 125,000 BTU per US gallon
- US$4.50 per US gallon
- Profit to retailers: < 2%



- Water and corn syrup
- 1,500 calories = 6 BTU per US gallon
- US$8.50 a US gallon
- Profit to retailers: > 30%

Gasoline and diesel are ridiculously cheap at least in the U.S. When oil prices rise to $200/barrel and higher over the next decade, that will change of course. 

I haven't delved into the economics of the infrastructure needed to deliver the amount of electrical energy required to recharge several 10 or 20 kWh batteries at a station in 5 minutes but I suspect it's not attractive at standard residential rates.

As for liquid Li ion batteries, the idea has legs but the latest estimate I heard from the well connected in this area is 10 years plus to iron out the bugs.

[Harlan]

I haven't read up on fluid-flow tech yet, but one potential issue that comes to mind w.r.t. EVs is that you aren't refilling one large tank, but possibly hundreds of tiny ones. How do you make sure all those cells get emptied and filled? And what about hose routing, especially when it can be a challenge to get even the BMS wiring cleanly into an EV? Exchangeable electrolyte will likely take a significant rethinking of how batteries are done in EVs. But hey, if it works...

I also agree with an earlier comment that 5-minute charging is unlikely to be common anytime soon. To fully recharge my 10 kWh bike pack in 5 minutes, aside from needing a 12C charge rate battery, I need 120 kW of power. And that's for a small bike pack. Think of 2-8x that for a car, times 10-20 simultaneously for an average corner station, and you're looking at multi-megawatt industrial-level electrical service.

I too am not convinced of the fluid-flow tech.  There are quite a few chicken/egg problems with it.

But I do think the 5-minute charge is not far away.  I think something you need to consider is the duty cycle of people charging vs. not charging. 

Just like at a gas station, not all the pumps are being used 100% of the time.  You'll need on site energy storage, (batteries), that are being charged while the station is not in use and then dumping energy when an EV plugs in.  This isn't any different than the hydrogen filling stations which are compressing the fuel and storing it while the station is not in use, or gasoline stations, except the tankers are the transport, not electric lines.

For your example a 120kW feed would be required if the station were being used 100% of the time, but that is unlikely and almost impossible as there is time between when somebody unplugs and the next one plugs in.  On the other extreme, if the station is only used once an hour, a 10kW feed is enough, twice an hour, you could nearly get away with a 240VAC 19.2kW service.

The trick will be having enough storage on site to handle the traffic, but I think that will becoming more common and more affordable as these EV battery packs are retired from vehicles but still have enough useful life for grid storage applications.

Grid storage really is an important part of optimizing our electric grid.  As it is now, electric service providers need to anticipate use, throttling up and down energy production according to historical values.  If they overproduce energy, they need to dump it somewhere and it is wasted, or even worse can cause a power surge that damages electronics.  Too little energy production and we get a black out.  Grid storage will give the electric service providers that extra fudge factor and make the grid operate more efficiently.