Dendrite build up, killing batteries

[batteryGOLD]

Country:
text
Sweden

my bad to think wrong contry, soo BDoctor is from Sweden! check time is there 02:58
soo the sleeping status maybe continues..

PS: do you know that brain is much more active during sleeping plus eyes movements? the sleep regenerate all brain and body cells tissues! Soo sleep as much as possible , but keep also active waked up exercised life to keep health forever!

 

[batteryGOLD]

Have not agreed with him much and try to keep that to myself. Was referring to before his latest 12 posts he posted once 18 months before that and once in 2019. Now there is nothing wrong with that. Just saying he maybe gone for a year or so.

Getting back to the thread!

Let's forget about past and see present. There are some great videos @ Battery Doctor channel!
past or future do not exist and both do not coexist, but are related/sequence! in this world only exists present moment clock ticking. Soo past are memories & future is maybe sequence or projections based on past & present.. past/future do not exist. only present is real. "I think & act, than I exist"

at this point WE request BDocGod to do video based on this dendrites topic and the EV 50% SOC safety method, if he wants..
soon BDoctor release new video (future event prevision..)

 

[tomjasz]

Doctor? Self proclaimed, YAWN.

 

[JackFlorey]

If this proves to be a good hypothesis, it would not be hard to design a charging circuit that occasionally spikes the charge rate for a second or two, but not long enough to cause too much heat.

OK that's a bit different. That's pulse charging, which is a non-monotonic current waveform during charging. Some use high current pulses, some even use short high current discharges during charging. Often they are touted as a way to allow faster charging without the usual battery damage. I've seen several companies propose such schemes but I have not seen definitive long term data on any of their schemes. (Generally they are lab cells cycled over a few weeks/months.)

 

[batteryGOLD]

unfortunately there is no science that could prove and no formula for math function results of dendrite build simulation over time..
it's similar to try to predict ants movement at a colony.. but it have some kind of pattern..

no camera inside lithium cells, so we can't see whats really happening inside those over time interval, we can't do a timelapse video inside a lithium cell! the only way maybe X-ray pictures over time..

pulsed technics could be the next step study. similar to pb batteries, some chargers have special pulsed mode to charge/recovery of those type of batteries.
In lithium world there is no study yet about this pulsed charge/discharge, but should be a good ideia.
A quick current pulsed at charge could kick out those dendrite crystals out of tha way.. At this moment we are thinking soo, I could possible regenerate a cell back to young age or back to new? Answer: I don't know!
or is just a continuous prevention dendrite grow method, does not regenerate cells, but delays end of life point..

sorry my english..

 

[batteryGOLD]

at this moment(Sweden time 17:40) BatteryDoctor maybe checking his statistics @YT studio and he sees good peak views at his channel! and also should have more subs at his channel. but lets be honest, He deserves those!

I've checked BDoctor channel,he doesnt post since 4days.. maybe he is into holidays! *(he likes high voltages, thats why he is showing a 42.6V(measured 42.7V) charger for extra power boost. I imagine the battery has HV voltage rate cells, such as 4.35V rated cells, or maybe using 4.2V cells but bms cut at 42V who knows.. lucky HV lithium cells could go up 4,45V) *edited

keep up waked for education & learning plus be polite! Thanks

 

[fechter]

There are other failure modes beside dendrite formation, so we have to keep all of these in mind. Most failure modes can be avoided by proper charge/discharge parameters. Some failures are a result of manufacturing defects that we have no control over during use.

 

[batteryGOLD]

text
Some failures are a result of manufacturing defects that we have no control over during use

Yeah you say true.
imagine you buy a new battery. example U plug battery into your Eveicule and than charging you only reach 90%(or other percentages, it will pass most times unnoticeable by user.. no battery recall..)
This happen with some low frequency, but exists. (recall Guinness records should be now at onewheel company.. just sayin.. )
Means a bad quality control of product. Lets say a ebike battery with this issue, if only charge up to 90% means some block of 10S array is a limiting factor and unnoticeable by user.

Visualize example, a 10S battery array with all blocks at 4,1V except one at 4,2V. this one will trigger bms top cut voltage, leaving the rest 9 blocks at 4,1V (this means only 90% of battery available) one cell is going to suffer more stress, causing battery to failure earlier time. the higher voltage cell will create more IR over time(+ dendrites..), this is a limiting element.

possible cause: Different voltage cells were mixed at battery built and not controlled. Battery needs to be rebalanced.
or other possible case is a higher IR internal resistance block P or a mixed defective cell at one block P ..

 

[ZeroEm]

Car Companies are performing tests (feel like we have been here before) and cutting the batteries open to measure the dendrite build up! Wished they would share all the results but they are competing with each other.

by batteryGOLD » Dec 17 2022 10:59am

unfortunately there is no science that could prove and no formula for math function results of dendrite build simulation over time..
it's similar to try to predict ants movement at a colony.. but it have some kind of pattern..

no camera inside lithium cells, so we can't see whats really happening inside those over time interval, we can't do a timelapse video inside a lithium cell! the only way maybe X-ray pictures over time..

pulsed technics could be the next step study. similar to pb batteries, some chargers have special pulsed mode to charge/recovery of those type of batteries.
In lithium world there is no study yet about this pulsed charge/discharge, but should be a good ideia.
A quick current pulsed at charge could kick out those dendrite crystals out of tha way.. At this moment we are thinking soo, I could possible regenerate a cell back to young age or back to new? Answer: I don't know!
or is just a continuous prevention dendrite grow method, does not regenerate cells, but delays end of life point..

Have not seen his videos, if he is suggesting to viewers to over charge cells beyond specs! This would be one of the times I disagree with him. Could go for .01-.02 for balancing and what not. Just think that 0.45 maybe to much and could cause issues. What was the benefit?

by batteryGOLD » Dec 17 2022 11:40am
I've checked BDoctor channel,he doesnt post since 4days.. maybe he is into holidays! *(he likes high voltages, thats why he is showing a 42.6V(measured 42.7V) charger for extra power boost. I imagine the battery has HV voltage rate cells, such as 4.35V rated cells, or maybe using 4.2V cells but bms cut at 42V who knows.. lucky HV lithium cells could go up 4,45V) *edited

 

[JackFlorey]

no camera inside lithium cells, so we can't see whats really happening inside those over time interval, we can't do a timelapse video inside a lithium cell! the only way maybe X-ray pictures over time..

You can test 1000 cells and cut one open a day over the course of 3 years. You can also X-ray them - and people have done just that.

In lithium world there is no study yet about this pulsed charge/discharge

There are tons of studies. Three of the talks I went to at AABC talked about pulse charging regimes.

A quick current pulsed at charge could kick out those dendrite crystals out of tha way.

1) They are not crystals
2) A high voltage gradient (caused by a high current) CAUSES dendrites.

 

[tomjasz]

Battery doctor only promotes his channel for income. He has no doctorate and close scrutiny reveals his obtuse views and shameless self promotion.

 

[batteryGOLD]

In lithium world there is no study yet about this pulsed charge/discharge

There are tons of studies. Three of the talks I went to at AABC talked about pulse charging regimes.

A quick current pulsed at charge could kick out those dendrite crystals out of tha way.

1) They are not crystals
2) A high voltage gradient (caused by a high current) CAUSES dendrites.

Yes Sir, U are correct, It seems to exist many studies over many years.. but at this moment, maybe 90% of lithium chargers will just put out constant current charging and decrease current until reaches top charge..
The pulsed tech is mostly used for Pb batteries, example "reflex charging"

Google Sources:
A: "what are lithium cell dendrites?"
R: "Lithium dendrites are metallic microstructures that form on the negative electrode during the charging process. Lithium dendrites are formed when extra lithium ions accumulate on the anode surface and cannot be absorbed into the anode in time.24/08/2020"

A: "What is dendrite formation in lithium ion battery?"
R: "Lithium dendrite formation, i.e., a neural-like network of metallic growth that can form at the anode/electrolyte solid/liquid interface during charging, is a main challenge in terms of safety and durability of the Li-ion battery technology, since they can short circuit the battery cell and cause the battery to catch ..."

A: "What is a reflex charge?"
R: "Reflex charging consists of alternating charge and discharge pulses. It is important that the number of cells (11,19,20,22) be identical to the switch setting because the rate and duration of the negative pulses is based upon a full charge voltage of 1.60 times the number of cells for which the switch is set..."

 

[JackFlorey]

The pulsed tech is mostly used for Pb batteries, example "reflex charging"

Traditionally, yes. These are now also being used for EV batteries to achieve faster charge rates.

 

[liveforphysics]

no camera inside lithium cells, so we can't see whats really happening inside those over time interval, we can't do a timelapse video inside a lithium cell! the only way maybe X-ray pictures over time..

You can test 1000 cells and cut one open a day over the course of 3 years. You can also X-ray them - and people have done just that.

In lithium world there is no study yet about this pulsed charge/discharge

There are tons of studies. Three of the talks I went to at AABC talked about pulse charging regimes.

A quick current pulsed at charge could kick out those dendrite crystals out of tha way.

1) They are not crystals
2) A high voltage gradient (caused by a high current) CAUSES dendrites.

I was at AABC too, you should swing by our lab next time you're in SoCal Jack.

 

[JackFlorey]

I was at AABC too, you should swing by our lab next time you're in SoCal Jack.

Cool. I live in San Diego - so it wasn't at all far for me.