Charging battery faster

[Hummina Shadeeba]

I don't think fast-charging is even necessarily detrimental. I've seen studies showing methods of fast charging, mainly high pulses, that have shown to destroy dendrites and even increase capacity in lithium or other chemistries. It's hard to find the exact regiment used though without paying for some of these private libraries

It wouldn't be hard to cycle one or two cells on some regiment if someone had the right tool
Mayne fast charging to 3.9 and tapering to finish at 4.1 or something shows better than even going fully to 4.2

 

[flat tire]

Regimen, not regiment.

In the paper "Dynamics of Lithium Dendrite Growth and Inhibition: Pulse Charging Experiments and Monte Carlo Calculations" it's not clear that they're fast charging. The pulses have a wait period and it doesn't give enough data in the summary. The overall rate could be well below 1C.

The preponderance of evidence makes clear that fast charging has drawbacks in pack life and capacity. Whether these are important enough to matter depend on the chemistry, how fast you charge, how hot the cells get, how long you keep the pack, how much the pack is being abused otherwise, and undoubtedly some more stuff.

In general, charge <=1C unless you are OK with earlier pack degradation.

 

[docware]

I don't think fast-charging is even necessarily detrimental. I've seen studies showing methods of fast charging, mainly high pulses, that have shown to destroy dendrites and even increase capacity in lithium or other chemistries.

PULSE CHARGING (PC)

Here is citation from the document "Aging of Lithium-Ion Batteries in Electric Vehicles" :

„ Other studies, however, showed that PC had no or even detrimental effects on the performance and cycle life of lithium-ion batteries [220 ⁠ ,226]. Numerical simulations based on a 1D physicochemical model indicated that pulse charging with fixed frequency and fixed duty cycle does not have any advantages over CC charging with the same mean charging current [33 ⁠ ,224]. Another study showed that for an identical mean current, losses rose and efficiency decreased with an increasing deviation of the charging current from a CC profile [220].“ ( page 75)
https://endless-sphere.com/forums/viewtopic.php?f=14&t=101500&p=1483921#p1483921


FAST CHARGING

Another citations from above-mentioned document :

„First of all, fast charging with high charging currents should not be applied for every-day use to avoid lithium plating and high stress for the electrode materials.“

„Results of Boost Charging and Supercharging
The BC and SC protocols apply a high charging current only at a certain SoC regime. Although it has
been beneficial to avoid high charging currents at high SoC regimes, where the anode potential is
lowest, the high charging currents have still caused disproportionate degradation at lower SoCs.“

(pages 105, 106)

Citation from Cleantechnica article about Tesla fast charging :

„Fast charging stresses a battery, and doing it too often or at too high a rate can shorten a battery’s useful life.“
„As Tesla explained, many things can reduce the lifespan of a battery pack, including charging at a high C rate.“
https://cleantechnica.com/2017/07/09/tesla-limiting-supercharging-rates-frequent-users/

 

[flat tire]

And this dude is trying to raise $40k to engineer a motor?

 

[dustNbone]

I don't think there's any universal maximum charge rate for lithium cells, it comes down to their physical construction, that's why they all have different ratings.

For example, charging my 20Ah A123 pack at 2C isn't "fast charging" at all, it's well under their specified limit. They won't even get warm to the touch.

 

[docware]

I don't think there's any universal maximum charge rate for lithium cells, it comes down to their physical construction, that's why they all have different ratings.

For example, charging my 20Ah A123 pack at 2C isn't "fast charging" at all, it's well under their specified limit. They won't even get warm to the touch.

You are right, we should specify cells chemistry.
Looking at his MX18650-26P noname chinese cells specification is not very comforting. I would try to avoid such purchase.
This battery and scootergrisen´s knowledge can be mixture dangerous to him and people around.
Reading his posts, I think there are two possibilities : either he is joker or …….

 

[Hummina Shadeeba]

Battery university's graph has lithium ion on it as potentially ultra-fast chargeable, so 10c up to 70%soc but there's no
graphs of cycle life with ultra-fast charging with different lithium ion chemistries or models or details. It seems the ultra-fast charging regimes done by car companies is proprietary info and hard to get but someone surely has done some testing.


flat tire Im not raising money to engineer a motor and ive been designing, making, and selling motors for four years. im raising money mainly to pay for the many expensive molds that need to be made to pour custom polyurethane. 13k. actually will be throwing a bunch of bucks in myself in the kickstarter and pulling it out again and I don't need to raise 40k really, more like 25k. any questions?

 

[flippy]

I don't think fast-charging is even necessarily detrimental.

then you think wrong.

I've seen studies showing methods of fast charging, mainly high pulses, that have shown to destroy dendrites and even increase capacity in lithium or other chemistries. It's hard to find the exact regiment used though without paying for some of these private libraries

cells made in labs with specialized chemistries does not make useful data in real life with commercial cells.
and even if fast charging had a positive befefit it would be negated by the loss in capacity.

It wouldn't be hard to cycle one or two cells on some regiment if someone had the right tool Mayne fast charging to 3.9 and tapering to finish at 4.1 or something shows better than even going fully to 4.2

these tests have been done by me and a few others and they all show massive degradation curves.

 

[Hummina Shadeeba]

Flippy "detrimental" is vague but the lithium titanate chemistry is commercially available and capable of ultra-fast charging.
https://lithium-titanate-battery.com/lto-battery-18650-1300mah-2-4v/

commercially available cells that improve capacity with pulse charging:
http://kohl.chbe.gatech.edu/sites/default/files/linked_files/publications/2001_The%20effects%20of%20pulse%20charging%20on%20cylcing%20characteristics%20of%20commercial%20lithium-ion%20batteries.pdf
(but im not really interested in pulse charging and just brought it up as an example of a high current being used. it's not practical for me to pulse charge. Ive never seen a charger that does it)


do you have the graphs of your ultra-fast charging and the chemistry? Im more so wondering about at what current it would still be considered safe if doing it to 70%soc and what can you look at to determine if the charge is safe. Is heating the sole indicator of detrimental effects? could the cells even be cooled to keep within a temp range and ultra-fast charge with less loss of capacity and more safety?

I got onto this question after throwing lots of 30Q cells in parallel that were at 3v and 4v and found that the heat maybe increase 5f at most. after 5min the voltages were 3.64 and 3.84. Surely will reduce the life cycles of the cells but sometimes that's not as important as charging as fast as safely possible for me. going with ohm's law to figure the current that passed into the charging cell and assuming .04ohms for each of the two cells I get 12.5amp flow and barely warm. (I assume I should use the resistance of the two cell added in the math). If heat alone is the indicator or even cause of the cell's deterioration it seems to be produced more often when discharging than charging. ( after this 5min burst both cells were almost unnoticeably warmer but seemed the same temp)

 

[spinningmagnets]

I'm not an engineer, but the easiest way (IMHO) to find out the fastest charge that is possible (*cell chemistry + pack size) is to monitor the temperature of the pack.

During the CC "bulk charge" phase, slowly raise the amps until the pack is at the warmth level that you feel is safe.

 

[flat tire]

lithium titanate

Yes, cuz there are a bunch of ebikes with lto batteries. Oh wait there aren't because the specific energy is garbage.

 

[Hummina Shadeeba]

I'm not an engineer, but the easiest way (IMHO) to find out the fastest charge that is possible (*cell chemistry + pack size) is to monitor the temperature of the pack.

During the CC "bulk charge" phase, slowly raise the amps until the pack is at the warmth level that you feel is safe.

but is heat the sole indicator of dangerous damage? I guess im fearful of dendrites forming and the cell internally shorting. will ultra-fast charging just reduce the capacity and cycles or increase the chances of internal shorting?

flat tire looking on wiki they state the titanate cells can have the same energy density by weight as lithium iron cells and up to 10x the lifecycles! I don't know prices but that's something maybe a biker would want, but I don't use them on a bike. pretty fantastic and didn't realize there was a lithium cell that potentially had so many cycles, if true.

 

[flat tire]

For someone who thinks he's competent to develop and put a motor into production you're not even trying. I mean, really. This is ridiculous. You don't seem to care about the facts, you just want to bullshit with members here.

Fast charging li-ion is inherently harmful even with heat removed although heat makes things worse in a hurry. This is a MATTER OF FACT. Lots of smart researchers have written about this. Go read yourself.

Claimed max energy density for LTO certainly doesn't approach good li-ion, although it is on par with some crappy high discharge RC lipo. Cells I'm finding on the market don't even hit 100Wh/kg.

 

[eee291]

I think you might have energy and power density confused, last I checked LiTo had a energy density of under 80Wh/kg while Li-ion is in the 140-270Wh/kg range depending on the chemistry.

 

[Hummina Shadeeba]

ugh. I wrote iron not ion in comparision to the titanate, which shows as I said on Wikipedia.

yes I believe ultra-fast charging will reduce the capacity of ion cells, Im wondering at what point it becomes unsafe.

flat tire please tone down the negativity

 

[docware]

will ultra-fast charging just reduce the capacity and cycles or increase the chances of internal shorting?

What about to read this study ?

https://mediatum.ub.tum.de/doc/1355829/file.pdf

 

[flat tire]

Lithium iron also sucks for ebike batteries for the same reason and it has worse power density. I will continue to call out flagrant examples of brain-deadness, and I invite you to do the same to me whenever my brain's missing.

 

[Hummina Shadeeba]

as I said this isn't for a bike although I just recently helped someone make a bike with iron headway cells in it. Please take the time to read what I write and stop attacking me personally

thanks for that docware looks complete

 

[scootergrisen]

Do anyone know of scooters that uses Lithium Titanate?

How come the Lithium Titanate batteries look like electrolyte capacitors with two pins at the end and +++++ on the side?

 

[Hummina Shadeeba]

I think depends on the model of the titanate cell but the cathode or anode, i think, is a greater surface area and more suited to being a flat cell.

from docware's paper:
Regeneration Effects after Lithium Plating The cells which were charged with high charging currents and suffered from massive lithium plating have exhibited certain regeneration effects during idle periods. After each checkup procedure, in which the cells were charged and discharged with substantially lower currents than in the highcurrent charging cycling test procedure, a considerably higher capacity was available in the cycling procedure directly after the checkup measurement than directly before the checkup.

 

[flippy]

Flippy "detrimental" is vague but the lithium titanate chemistry is commercially available and capable of ultra-fast charging.
https://lithium-titanate-battery.com/lto-battery-18650-1300mah-2-4v/

name one consumer product that uses them. even if you can find a single consumer product then my conclusion still stands.

 

[flat tire]

Those LTO cells are threaded (male) so you could bolt together interconnects. Personally I like LTO but it's not there for my ebike use. Apparently the Honda Fit EV uses LTO too so you might be able to get a good deal salvage.

waaaaah

Nobody is attacking you personally, only your bad IDEAS and the absolutely ridiculous premise that someone with this much misunderstanding of basic stuff is trying to take $40k from the community to develop a motor. Stop posting half baked, easily refutable stuff if you don't like it.

 

[Hummina Shadeeba]

what are you refuting? what ideas? what is my misunderstanding?
im happy to discuss things civilly but you must know youre not doing that. Are you angry about something? sorry if I offended you somehow



flippy -titanate charge and discharge at 3c which would be considered ultra-fast charging according to battery u. if you look up the cells on Wikipedia theres a lot of consumer products using them. cars and bikes.

https://www.eetimes.com/author.asp?section_id=36&doc_id=1325358#

this article and graph is pretty vague though and hard to find info

 

[spinningmagnets]

I am in the middle of assembling an LTO 12V battery for a suitcase pack, and I have chosen LTO for it's multi-year cycle-life. The nominal voltage (as far as I know) is 2.4V "per cell", so it is not used for vehicles.

As far as "fast charging", I have read that the cells I bought can be charged very fast, but the low power density means that this chemistry is rarely used for a vehicle, so...it may be a moot point.

 

[flippy]

flippy -titanate charge and discharge at 3c which would be considered ultra-fast charging according to battery u. if you look up the cells on Wikipedia theres a lot of consumer products using them. cars and bikes.
https://www.eetimes.com/author.asp?section_id=36&doc_id=1325358#
this article and graph is pretty vague though and hard to find info

i clearly asked: show me a product you can buy -as a consumer- and is meant to be sold to consumers that uses these kinds of cells.
stop pointing to fringe cases and unicorn lab results. show me mass production consumer products.

preferably a amazon link if you be so kind so i can buy it with prime shipping.