Lithium replacement pack nearing market. Sounds great

All these conversations makes me more certain that I'm gonna stay away from all this in practice and just keep it to theory... Sure will be nice to one day have an electric car for a long time and never have to talk about the batteries.

 

There are definitely a lot of pros and cons here to weigh. The Winston batteries I was looking at would cost some $5,000, maybe more. And that would be a battery just shy of 9kWh. I'm sure there could be a cheaper solution, but the cheaper you go the more the risk since you'd be dealing with higher charge and discharge rates compared to smaller capacities, not to mention cheaper built batteries. And the Prius isn't really designed to take advantage of a bigger battery anyway. Plus, there's no way of really knowing if it's going to work and last unless someone else has done enough real-world testing on it, which may never really happen. So it's still a gamble.

On the other hand you could get a used Nissan Leaf for that much with about the same capacity. It would be a car designed to work with such a battery too, with charger and all. By the time you add a charger and modify your Prius to run in EV mode exclusively, you'd have spent even more and probably could have gotten a used Chevy Volt for cheaper. And when the battery goes to far south in that Leaf or Volt, there will likely be more alternatives for battery replacement that have been tried and tested time and time again.

 

I'm left shaking my head after reading the first few pages .....
Lithium ion is the type of chemistry, just like lead acid covers a multitude of different formats, but they all use the same lead acid reaction to work.
Lithium ion is the same, it is the lithium ions moving between the cathode and anode that provide the energy or energy storage.
The list of chemical combinations that use this lithium ion exchange in their operation is as long as your arm and still growing by the day.
The truly safe lithium chemistry batteries are LFP and LTO. LFP or lithium ferrous phosphate (LiFeP04) come in a number of different varieties, chemical make up and active material thickness. The best of these chemistries is LYP, lithium Yttrium Ferrous Phosphate. I believe Winston Chung holds the patent so you can only get them from Winston Thundersky battery in China. These are only built as prismatic cells with relatively thick material coatings on the plates. This thick material resists ion movement compared to the thinner material thickness and this results in voltage sag under high load and limits on recharging rates. If you want to see 5,000 cycles out of these cells, keep the discharge and recharge rates below 0.5CA, 50 amps per 100Ah capacity ... not really what you need in a Prius. To handle the sort of currents a Prius moves in and out of its traction battery you'd need a 300Ah battery, that's gunna take up a lot of room and weigh quite a bit.
Cylindrical cells are just one cathode and one anode plate wound up in a tube, very thin active material facings so they can move a lot of current in and out very quickly .... but they don't live near as long as the thick coated prismatic cells.
The real winner is LTO, lithium titanate. These cells can handle 30CA all day and all night and last long enough to put in your will. They are so safe they use them in human supplementary medicine like pace makers and nerve stimulators that are implanted in the body.
Their down side is they are not as energy dense as the really volatile chemistries like LPO, lithium polymer, these are the cells in model planes etc that explode into flame if mistreated.

So, if/when someone builds an LTO drop in battery to replace the NiMh battery, things will really change for the better. When I've saved enough bottle tops I plan to build a 55Ah one of these batteries and completely replace the traction battery and extended range battery I have in my '06 Prius now. I'll leyt you know when I'm in the process of doing it with photos etc and just how well or otherwise it works

T1 Terry

* I buil and install lithium off grid battery systems for RV's and off grid houses. We are in our tenth yr and our first battery packs are still going as strong as the day they were fitted. That's about the best proof you can get that we know what we are talking about

 

Yep... The writer of that Torque news article doesn't have an editor and doesn't learn from feedback on his articles, but treats feedback as unfair criticism rather than an opportunity to get it right.

The NexCell Lithium packs (Dr. Prius) that are about to come to market are LiFeP04.

And if you run across a good article that summarises all the battery tech coming our way please post it in the news section so we can have a more in depth discussion.

I'm especially interested in what you have to say about Sodium-Ion batteries that can ship at 0.0volts for safety and also the use of capacitors to extend the amount of charge / efficiency / lifespan in a battery.

 

The sodium ion battery is a way off yet, if it ever actually makes it onto the commercial production stage. They are only suitable at this stage for stationary storage like a grid smoothing battery or residential/commercial sized house power battery. Much like the Aquion salt water battery and the Redox battery, they are fragile so vibration would destroy them. At the moment lab sized test cells using exotic electrolytes are showing promise, but scaling up from the lab micro cell to actual usable capacity cells is the death of most wonder chemistries that work great in a lab in miniature for built under very controlled conditions but can't be scaled up because either the perfect cell can not be repeated in multiple layers to build capacity or strung in series to build voltage.
Even the Aquion battery, the brain child of Proffessor Jay Whitacre who made LFP batteries into a practical DIY affair and taking them away from the "in-house" secrecy of the likes of A123 who wanted to keep the technology for commercial use only.
If China was to take the next step into the developed world and actually do technological development rather than copy and adapt/modify like Japan did in the early days, then we would see some amazing technology leaps ahead ..... but no one wants to spend the big $$ only to have China steal the technology and sell the commercial produces off cheap because they don't have to recoup any of the R&D costs.
At the moment, LTO chemistry batteries are going through this reduction in price as the Chinese improve their production tollerances. Linyong would probably be at the head of the pack at present, but be aware that many resellers in China buy up the reject cells and sell them under a lower capacity rating at a lower price point. If you look at the 30Ah, 35Ah and 40Ah and 45Ah cylindrical cells, you will see they are all the same format size LTO Batteries,Lithium Titanate Battery,Yinlong lto 40Ah,Li-ion Battery but if you tell them you are after electric vehicle batteries, they will move up to the 55Ah cells ......

Still early days, first have to find the $$, then the time. I just bought a Blade Electron V, 2010 model of Australia's first attempt at manufacturing electric vehicles. I bought it as a nostalgic type restoration project .... but restoring it to what it's real potential should have been, not the unreliable mash of bits they actually rolled out the door :lol:

T1 Terry

 

I wonder how the voltage of LTO's compare with NiMH modules/blocks. The nice thing about LFP is that 5 in series equals the voltage limitations of 12 NiMH in series, making them a direct replacement for each 12-cell block of NiMH as is the case in many Toyota Hybrids. This makes it so much easier since now you don't have to do anything special to make the Toyota battery management system happy. Just connect each lead for each block at every 5 LFP series of cells and it will be happy.

If the maximum and minimum voltages of a series of LTO cells can mach a block of Toyota NiMH cells then it would work easily. But if not, you'd either have to leave the NiMH battery in there and just connect in parallel to it, or rig up some sort of device to fake block voltages to make the Toyota BMS happy.

From what I understand Tesla is now making their standard range Model 3's with LiFePO4's. I wonder if you couldn't harvest some of those from a wrecked Tesla and put them in a Prius.

 

Wrecked Tesla Battery harvesting is super crazy! And every year Tesla makes it harder... Check out Youtube if you want to see how ridiculous it's getting.

 

LTO cell range is 1.5v to 2.85v, from memory the two packs in the original traction pack has a nominal voltage of 14.4v per 2 packs, and this ranges from 12v to 17v or even 18v because I've seen 254vdc on my scan gauge in my Gen Prius.
There are 14 2 module packs that the Prius voltage monitors .... and maybe balances but not too sure about that bit. This means 6 x LTO cells in series fits perfectly within the 12v to 17v range and still stay well within their safe range. 5 x LFP cells do not fit well within this voltage range, the lower end is only 2.4v per cell and the upper end is only 3.4v per cell .... the voltage of a fully charged cell but not high enough to fully charge the cell at 3.45v x 5 = 17.25 and really need to be 17.5v to get the cells charging at the 3.5v required for fast charging to 100% SOC. Add to that, LFP cells will charge at 3CA (3 x their rate capacity) but to get the cycle life the limit neds to be around the 0.5CA (50% of their rated capacity) An LFP cell pack will work, but the cycle life would be poor.
The original traction battery is 6Ah, 6 x 201v = 1200Wh, ok for short regen/boost but that's about it and really all it was designed to do.
A 6 cell x 14 pack 55Ah LTO traction battery would deliver 201.6v nom, sbout the same as the original, but multiply that by 55Ah and you get 11088Wh or 11kWh to replace the 1.2kWh the original battery provided. Up grade the pack to 2P84S and you have 22kWh or around 120 mile plus all electric range, but devastating acceleration in mixed mode or great fuel economy with a lot of regen capacity and a refuel at a power point at home or a 1 hr fast charge or less at a high output DC charging station ........ you can't have all of those things at the same time, so pick the ones you like :lol:

T1 Terry

 

I just got it……


Source: iPhone 12 Pro Max 512GB ? Pro

 

Hilarious…..!!!


Source: iPhone 12 Pro Max 512GB ? Pro

 

That's not what I've read. Charging to 3.6V or 3.7V seems to be very common. And from what I've read and been told LFP can withstand up to 4.0V although up to 3.8V seems to be still plenty safe. So it's not like the Prius will charge them up to 3.5V each and then all of the sudden your battery dies. As far as I've read the maximum Prius block voltage is 18.7V which divided into 5 is only about 3.74V per cell, still under 3.8V.

The lower end is a bit worrisome, but still seems to fit the characteristicts of the Prius BMS system. 2.4V x 5 = 12V I'm pretty sure the Prius BMS never lowers a battery block that low, especially at resting voltage. But I have seen specs saying 2.5V or even 2.8V is safer. 2.8 x 5 = 14V, which is still whithin range

[QUOTE="T1 Terry, post: 3147070, member: 133102"the voltage of a fully charged cell but not high enough to fully charge the cell at 3.45v x 5 = 17.25 and really need to be 17.5v to get the cells charging at the 3.5v required for fast charging to 100% SOC. Add to that, LFP cells will charge at 3CA (3 x their rate capacity) but to get the cycle life the limit neds to be around the 0.5CA (50% of their rated capacity) An LFP cell pack will work, but the cycle life would be poor.
The original traction battery is 6Ah, 6 x 201v = 1200Wh, ok for short regen/boost but that's about it and really all it was designed to do.
A 6 cell x 14 pack 55Ah LTO traction battery would deliver 201.6v nom, sbout the same as the original, but multiply that by 55Ah and you get 11088Wh or 11kWh to replace the 1.2kWh the original battery provided. Up grade the pack to 2P84S and you have 22kWh or around 120 mile plus all electric range, but devastating acceleration in mixed mode or great fuel economy with a lot of regen capacity and a refuel at a power point at home or a 1 hr fast charge or less at a high output DC charging station ........ you can't have all of those things at the same time, so pick the ones you like :lol:

T1 Terry[/QUOTE]
There are pros and cons to everything. Is 0.5C really necessary on cells rated for up to 3C? What would be the actual longevity either way? Remember too that for hybrids we're generally not talking about constant 0% to 100% charge and discharge sessions like on EV's and plug-in hybrids, but small bursts here and there. I see no reason to add a DC quick charger onto my house to fill up my hybrid's battery. Also, how can you be sure there's only one brand of LiFePO4 batteries that's a good brand? And where can I get LTO cells if I were to build an LTO HV battery for my Prius?

At any rate, it's not that I'm not somewhat skeptical of putting LiFePO4 cells in a Prius, although I also sincerely hope it works and believe it can with the right cells. From what I'm getting from this thread Winston cells aren't the way to go, but maybe these NexGen cells will work. What would be nice to me, either way, is to have more efficient cells and a bigger battery: bigger battery for when I do travel over mountain passes so that I can absorb more of the downhill energy. I don't see another reason for having a bigger battery in a hybrid unless you do a plug-in conversion.

 

So if the Lipos suck, then...? Although I hope they don't.

 

depends on the type of lipo. everyone is experimenting, we'll see what pans out. there's still nimh, tried and proven

 

I just bought a bank of Yinlong LTO to replace my 12v battery, if I could use the same cells to replace the HV pack too that would be amazing!

6x 14 packs is a lot of cells though, finding space and weight for it might not be viable even with the massive increase in capacity

 

There are many different types of LiPo (Lithium Polymer) batteries... Some are better than others. Don't trust advice from someone who can't differentiate between the different types of LiPo.

 

Thanks! It was a pun was all. I understand the difference. Thanks!

 

It looks like the smallest Yinlong LTO cells are 28AH pouches. But it seems hard to find Yinlong cells for much less than $100 each. That's way too prohibitive. Maybe at $50 a cell. Alibaba has some for $25 to $35 per cell, which would be more like it. I'm suspicious of Alibaba though.

Still, there's not a lot of info on them that I can find. How long do they really last? Does heat and cold damage them like with other batteries, and by how much? I know people who have used LiFePO4's before and have a good idea of what to expect.

 

I've been working with LFP and LYP cells (LiFeP04 and LYFeP04) for over 10 yrs. I spent AUD$10,000 buying cells to do the genuine testing because what you read on the net is some arm chair experts complete lack of understanding about what they are reading or talking about.
The 4v per cell refers to being charged at 0.5CA until the charge current drops to a percentage of the cell capacity, then charging stops and the cell is allowed to rest so the voltage can settle. This is lab equipment type charging, not out in the real world charging. Take the cell over 3.45v and the voltage and internal temperature will climb rapidly. As the cell voltage reaches 3.8v this climb is near vertical as far as voltage and heat, so in the lab type charging it is very quick so very little temperature saturation occurs in the cell.
You want o build a 5 x 14 cell battery, charge it at up to 3CA with absolutely no way of balancing the top end capacity of the cells and want to charge them to 3.8v or even 4v per cell ........ hope you have a big wallet.

Sure, buy the cheapest cells you can find, it's your money, but don't come on here after a few mths complaining that the lithium cells are rubbish because you bought garbage and they failed .....

T1 Terry

 

Exactly! There is a large difference in quality. My 2013 Ford hybrid uses a lithium pack and now has 184,000 miles. It’s gone 69,000 miles on the hybrid battery alone (not a plug in hybrid)it just uses the the small hybrid battery a lot, even under some pretty heavy loads. That tells you right there they are using quality lithium cells.

With my experience of driving a “older” car with a lithium battery I’m nothing but thrilled and impressed, fully supportive of the Prius community creating these quality after market lithium packs.

 

I can see the problem. So you think this "new product" being advertised as a NiMH to LFP replacement is a fraud? Looks like NiMH Prii are meant to have NiMH batteries, and that's it. If LFP/LYP don't work, and LTO's are way too expensive, then there's no point.

Another thing I think I'm seeing about LTO's is that their charging characteristics are much further out of range than the NiMH charging structure. Basically they'd never get close to fully charged or fully depleated. While that makes sense for longevity, it also means you'd never get their full potential. What percentage exactly, I don't know. But if you get like 50% or something like that it would kind of defeat the purpose.

NiMH batteries are 6Ah but you get around 3Ah in real world use.
60Ah Winstons would cost about 3 times a NiMH but in theory would give you nearly 20 times what the NiMH give
28Ah LTO's would cost about 4 times what a NiMH battery would and would give possibly around 4 times the energy.