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iMiEVNZ7

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http://www.digitalcamerainfo.com/features/4-battery-concepts-that-could-change-the-world?utm_source=usat&utm_medium=referral&utm_campaign=collab

Looks like by the time our batteries fail, the replacements will be lighter and more powerful.

In the meantime we went and brought a Prius C to get us a part electric car,for our longer range and round town work, and once the Chademo Chargers are available in NZ we will go ahead and buy four iMiEv's we think, which should help convince others in NZ that the car is practical for the type of usage we expect it to be used for, helping Tourists go to local areas within 80 - 100 km of Canterbury and getting back after a few hours after having lunch or a boat ride or similar.
 
Thank you for this informative article.

We have already exchanged some thought on upgrading our batteries in a few years and I would like to submit this question to the more knowledgable forum members.

I think Don mentioned that the easiest path for upgrade would be to have the same battery chemistry, hopefully with equal to better properties, mainly capacity.

Here is my question, am I missing something in stating that the main characteristics of the replacement battery should be its max and minimum voltage in order to be a drop in replacement with our BMS ?

I would understand that it's maximum load would be 4.2v or higher and minimum if my memory is right no less that 2.95 or 2.75 ?

Then I would expect our BMS to be able to charge the new set of battery within its max and minimum boundaries, the only difference would be that even at 13 A, 240V it would take maybe 24 hours to charge say 40KW battery pack ?

Of course physical size to fit existing battery compartment would also be a criteria.

Second thought I have been having lately is about "Hybrid" batteries.

I could imagine similar to hybrid HDD combining rotational disks with SSD memory. To have maybe super capacitors combined with more classical Lithium batteries.

The advantage being that super capacitors of say 10% the capacity of the main pack would act as a buffer for the regen back and forth charges, therefore largely reducing the aging of the main battery pack.

Looking forward to comments.

Thanks.
 
I would imagine our BMS was specifically tailored to the type/size/chemistry battery the car came with, so realistically, a 'replacement' battery would likely consist of a pack of refurbished cells salvaged from other packs, keeping the good cells and discarding the bad ones *or* something much more expensive which consists of an all new pack probably of a different chemistry which comes with it's all new, matching BMS - The BMS really controls the way the pack is charged, so I can't imagine adapting some other pack to our existing BMS

I'm hoping they sell enough of these cars that when the time comes, I could exchange my pack for a refurbished one which would give me 80 to 90% of the range the car had when it was new for a modest price - I think that's our best, most realistic hope . . . . unless you're willing to drop lots of money into an 8 or 10 year old car

The other option would probably be to grab up a collision damaged iMiEV somewhere along the line so you'd have the cells to do your own battery refurbishment project when the time comes

Don
 
Thank you Don.

Could you be more specific as the specificities of the BMS for specific battery (other than the max and min voltage ).

Could it be the speed of charging, any particular frequency. I am really trying to understand those particularities.
 
To be honest, I know very little of the specifics of the BMS - Mitsu hasn't told us all that much that I can find

"Battery management system. The Battery Management System consists of the battery management unit (BMU); cell monitoring units (CMU) that monitor the state of each individual lithium-ion battery cells (one CMU per battery cell; a total of 88 cells in each vehicle battery pack); a leakage sensor to determine if there is any leakage from the high voltage system; and an electric current monitor to constantly watch over the battery pack’s amperage."

It just sounds to me like it's been specifically engineered to watch over the particular pack the car came with - Doesn't sound 'generic' enough to me to be easily adapted to do what it does with cells of different voltages or composition

I could very well be wrong - But if I was thinking of using a pack made up of a different number of cells of some other voltage than those that came with the car, I would be planning on it having a BMS tailored to that particular pack . . . . and whether or not that new BMS will talk to the ECU in the car or not remains to be seen

Maybe, one day someone will actually find a way to adapt the car to use a more modern pack made up of better, higher density cells which will give you 150 miles of range . . . . but myself, I kinda doubt it - Unless[b/] Mitsu one day offers a drop in replacement pack designed to work with all the electronics in the car. I just don't see an individual user replacing the 88 cells in our pack with something else and getting it all to work properly

Don
 
I like to think that the energy density of current batteries is comparatively low because they batteries not only store available energy, but also our "spent fuel". Gas-powered cars would have terrible range if they had to contain the air used to combust gasoline. Every 30 miles or so they would have to change air tanks because they would have used up all the oxygen. That's why lithium-air batteries can deliver 10 times more energy than current batteries. They don't contain all the materials needed and rely on the atmosphere to complete the reaction.
 
Llecentaur said:
Second thought I have been having lately is about "Hybrid" batteries.
I could imagine similar to hybrid HDD combining rotational disks with SSD memory. To have maybe super capacitors combined with more classical Lithium batteries.
The advantage being that super capacitors of say 10% the capacity of the main pack would act as a buffer for the regen back and forth charges, therefore largely reducing the aging of the main battery pack.
Looking forward to comments.

I don't hold a lot of hope for super/ultracapacitors, though I do have a big pack of em in my garage! :mrgreen:
Power density for brief discharges is awesome, but energy density on ultracaps is rather low from both a volume and mass standpoint, and the recoverable energy from ultracaps within the narrow voltage range of a lithium pack is a very small percentage of the total energy contained in the capacitors because they have a linear discharge curve (discharging 10% of their energy causes the voltage to fall 10%). My pack came from Azure Dynamics' bankruptcy, out of their R&D lab in Canada. Azure built a prototype of their Balance Hybrid Bus with ultracaps instead of batteries, for a quick boost on acceleration and regen storage only, but it did not pencil out. A friend in Portland used ultracaps in buddy pairs with early lithium cells around 2004. He found that though the ultracap buffer did smooth out the charge/discharge curves during driving, he was better off replacing the ultracaps with additional lithium cells.

My intent for the ultracaps is as a parallel pack to the nickel-cadmium pack in my drag-racing converted EV, where the volume penalties don't really matter, and keeping the motor in both voltage limit and current limit for a couple more seconds should be worth the extra weight. It will, however, make the batteries take longer (almost 2x in my application) to recover their voltage after a 15 second, 1000 amp discharge because the ultracaps will be pulling out amps as fast as they can be made during recovery, slowing the rise in voltage. Not a factor on the drag strip, but it doesn't help a vehicle that may need to accelerate again without some time for the pack to rest. In effect, with a matched ultracap the battery sees discharge events that are half as intense but twice as long (or 25% less intense and 25% longer in duration, etc. etc.). With a mismatched ultracap or a longer discharge event than designed, the capacitor could give a brief boost to the discharge, and then it is just dead weight that slows acceleration). I intend to manually control for this with contactors that bring the capacitor pack in and out of the circuit at the point at which the voltage/discharge curves cross and the capacitors become a liability rather than an asset, and to possibly charge the ultracap bank up to a higher voltage than the battery bank. I'll begin a run on battery alone, but once the battery voltage sags to a certain point, bring on the ultracap boost. Likewise, I'll be able to experiment with launches on ultracap alone, and then switch in the battery (or switch over to battery alone).
 
Seems Renault/Nissan will try this "1.000 miles" Aluminium/Air, as a Range Extender:

http://www.hybridcars.com/renault-nissan-to-use-phinergys-aluminum-air-battery/

Perhaps in 2017...
 
That is very cool. Think it'll come to fruition or will the "powers that be" prevent it?

Road-trippin' in the MiEV! :cool:
 
NeilBlanchard said:
The aluminum / air battery cannot be charged. You have to replace the core of the battery physically in order to "charge" it.

You charge your usual Li-ion battery, at home.

This is a range extender, not a main battery.

With the BMW i3 REx, if you past your battery range, you spend 6 liters of gas each 100 km (don't know in US units)
With this system, if you past your battery range, you "spend" (can be recycled, at a cost in electricity) 2 kg of aluminum each 100 km

Is other system of REx. You replace your "fuel" from gas to aluminum.

We will see...
 
6 L/100km is roughly 39 mpg. 2 kg is 4.4 lbs.

So, for every 100 km (62 miles), you consume 5.1 kg of gasoline, vs. 2 kg of aluminum. To go 1,000 miles, you would need to carry 25.6 gallons of gasoline (97 liters). You start off with a fuel weight of 82.45 kg. The aluminum battery starts with a weight of 100 kg. So the aluminum battery is heavier than 97 liters of gas, but you don't have the added weight of the gasoline engine and related equipment.

Similar energy/weight ratio as a gasoline range-extender, but this is much cleaner and renewable.

Maybe the aluminum/air battery shouldn't be called a battery(?)
 
I wonder how well to wheel efficiency compares to a hydrogen fuel cell. Though if these are "recharged" with pure hydro power, that may be a moot point. You certainly don't have the infrastructure and storage losses that hydrogen has, plus little risk of fire or explosion.
 
PV1 said:
Maybe the aluminum/air battery shouldn't be called a battery(?)

Perhaps, but no main battery.

It have the capacity (kWh) but no the power. Can only get about 20 kW. Enough (good!) for a range extender, but no to feed the motor in acceleration or climbs.
 
Two different working super-capacitors?

Surrey/Bristol: http://www.autocar.co.uk/car-news/new-cars/evs-could-be-fully-charged-seconds-following-supercapacitor-revolution

Florida: https://www.sciencedaily.com/releases/2016/11/161121162043.htm

Maybe long range and ultra fast charging is not that far off.

Positive thoughts for the coming New Year!
 
Well there's a huge difference between filing a patent, and getting a working small scale prototype in a lab. There's a huge step in taking a lab prototype and up-scaling to power something like a car; an even bigger step in actually getting a working one into a vehicle, and even once that's done - a way of bringing that to market - so it's going to be a long time coming.

It's a very exciting time, but the current technological revolution is a bit bi-polar, with so many evolving technologies to consider in a relatively unsure term, we seem to be hesitating about where to place our bets - which seemingly leads to delays and slower than optimal roll-out.

Again, a major part of the transport evolution to electric is about having enough electricity available at the right time, and that's something we are a long way away from. You can imagine a situation where you could charge your car with say 30KWh of juice in 1-2 mins, but thats not going to be possible with current domestic power, so the only solution would be a gas station setup with an absolutely huge electricity supply - which needs to be available - so I suppose if the grid is able to take it, you would have to book a slot throughout the day to go charge, and clearly peak electricity would have to go up a lot in price, while off-peak would have to go down a lot. I can see that in the future, there will need to be a new pricing model for peak and off peak energy prices to load balance the grid, and chasing off peak times will mean you will have to keep going there to recharge at bedtime... until autonomous vehicles implicate that they can go there themselves. There are enough problems with grid load already from people coming home, turning on the oven and tumble dryer, and then boiling the kettle...

I also keep having these thoughts about the majority of car makers going under in the future, as there are only going to be a couple of producers that win this race. Huge automotive companies can very quickly go bust if their pipeline is wrong, and that would be a shame for workers and consumers. At this stage I cant see how we are going to get to a stage where we have affordability and choice, preserve workers jobs, and make products that can be repaired simply. Other than a pay per mile model, I can't see a private ownership model in the future where purchase price is higher than it is now, with the repairability where it is now. What you need is the ability to swap out broken parts like cells or a motor with ease, so that a single component failure doesn't render you with a problem that is logarithmically more significant than it is now. And that is something exemplified by Mitsubishi with a complete battery pack being one part number... it's only OK if you can guarantee that it won't fail for a very long time, and that if it does, it's taken care of.

Does this mean that in the future I will be able to ditch my oven and microwave and cook my pizza in 3 seconds in a superconductor oven?
 
Why not have a battery bank that runs the quick charger? The energy storage medium would have a 10 kW grid charger. The EV gets a rapid charge without slamming the grid.

A single Model S battery pack could easily power a 50 kW quick charger and run it at full output for an hour without any energy input (assuming the pack starts fully charged). Given that a car like the LEAF would only soak up 20 kWh at the most, a 10 kW grid charger would allow the station's energy reserve to fully recover in about 2.5 hours from fully recharging a LEAF, but there'd be enough to charge 3 more LEAFs in a row before the battery depletes and QC output is limited to 10 kW.

The "problem" of recharge time isn't because of the batteries, it's being able to get the power to them for larger packs. In the era of 200+ mile EVs, the cars should be able to sip enough energy overnight to cover a couple of days worth of driving, or at least stave off the need to quick charge so much.
 
Phximiev said:
Two different working super-capacitors?

Surrey/Bristol: http://www.autocar.co.uk/car-news/new-cars/evs-could-be-fully-charged-seconds-following-supercapacitor-revolution

Florida: https://www.sciencedaily.com/releases/2016/11/161121162043.htm

Maybe long range and ultra fast charging is not that far off.

Positive thoughts for the coming New Year!

More on the super-capacitors: https://chargedevs.com/newswire/could-a-new-supercapacitor-technology-replace-batteries/

And I agree with the thrust of the above comments that it is a long way from patent to my 'Miev.
 
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