Lipo vs. Li Ion same discharge rate risks?

[rg12]

Was wandering if identical pouch cells with the same IR, C rate and capacity will also have the same risks or the lipo since it's lipo will always be more dangerous because of it's chemistry?

I always thought it's the high discharge rate, but I know that many small devices use tiny pouch lipo cells with very low discharge rate and they are not known for such a thermal runaway hazard like you see in high discharge rate lipos.

 

[DogDipstick]

The proliferation of lipos beeing dangerous is a myth that was propagated by the hobby industry and cheap cobalt containing RC toy packs. Abuse and overpriced things and "Immagonna take the gasket out the ammo can cause its safer "( lol) stupid shit like that.

The true, ev grade, lithium polymer cells I have here from 2019, Chevrolet, new purchase... are very safe. Charge em full and stab em on vid with a screwdriver no fire, just lil smoke. they are true EV lipos on my bike. Shot em no prob. Drop em, get them wet, for months, no prob... Hit em till they get hot.. no prob... the NMC-LMO self-healing blend is amazing. Amazingly safe and tested. very advanced for its day....

R and D money those car companies have.

Now... Short it... ( connect + pole to - pole ( POS to NEG) and in one min it puffs and explodes. Not even. 20 seconds.. Sizzle sizzle pufff explode. thousands of amps (2000-4000A) will travel and the cell will burn its tabs and puff its pouch with the chemical reaction.

however, do this with a 18650 or a p24b and... well.. cell is destroyed just as fast.

If you let it hit 0v.. ( the lipo) it might also puff, but slow like a pillow ... and not explode, just look like its about to.

Same thing happens with hobbyking lipos.

They make both POWER dense lipos and ENERGY dense lipos. true lipos...

how are you discriminating against the two/ A " Lion pouch cell" vs a " Lipo pouch cell" ?

By sight? By datasheet? how and what are you describing ?

 

[DogDipstick]

... On the same note.. Just " short" one of those low grade cells in the cell phones... in the little devices... whatever... tiny pouch lipo cells with very low discharge rate and they are not known for such a thermal runaway hazard... Just short one of them..

and the same happens.

lithium polymer is the most widely used type of lithium battery in the world. easy to make a machine for manufacture compared to a steel can jelly roll machine.

So there are the most of them... and you hear they are safe.. " not known as a thermal runaway hazard " ( never loaded to that point.. duh)... cause there are more of them in application than any other kind of lithium cell in the world.

the cell phones. Every one has on in the pocket. A billion plus. Lol.

No they dont use 18650 in cell phones for certain reason and its not the " safe factor". they got a reason though for sure.

they are the best and work the best.

Whatever downstream the POS pole and the NEG pole is what the designer must insure with his product liability insurance.. not the battery problem. f you buy a cell and install it in a design and it right away burns and shorts thats your problem.. no the battery company.. battery just did what it was suppose to ( provide current). ( provide current to a KNOWN ENUMERATED DESIGNED loading. )

battery just there to make a current flow.

 

[rg12]

Now... Short it... ( connect + pole to - pole ( POS to NEG) and in one min it puffs and explodes. Not even. 20 seconds.. Sizzle sizzle pufff explode. thousands of amps (2000-4000A) will travel and the cell will burn its tabs and puff its pouch with the chemical reaction.

What cells did you talk about here?

My question is in general, if the lithium polymer chemistry is more volatile than lithium ion in a hypothetical situation where both datasheets are the same.

It's either that the chemical difference of lipos adds to the risk over li ion or it's just that they got a bad name from abusing them in hobby use until they puff like crazy or go up in flames since these are the only cells that can work in those hobbies since only they have the high power and small package.

Am no chemist, so my question is if used responsibly, same specs as the same li ion cell compared to, will the lipo because of it's chemistry be more prone to risks of puffing or thermal runaway?
*both lipo and regular li ion in pouch form

 

[LewTwo]

"Lithium polymer" is a type of "lithium ion" battery in a plastic (polymer) pouch. Ask the manufacturer about the chemistry used (anode, cathode, electrolyte) and they will likely ignore you. The reason that E-bike and other Electric Vehicle batteries are so dangerous is because they generally use much higher voltages, currents and capacities than cell phones, cameras and other small electronic devices use.

 

[rg12]

"Lithium polymer" is a type of "lithium ion" battery in a plastic (polymer) pouch. Ask the manufacturer about the chemistry used (anode, cathode, electrolyte) and they will likely ignore you. The reason that E-bike and other Electric Vehicle batteries are so dangerous is because they generally use much higher voltages, currents and capacities than cell phones, cameras and other small electronic devices use.

Polymer doesn't refer to the pouch form, it refers to the type of electrolyte.
There are lithium ion (not polymer) in a pouch form also.

My question is if the specs and use are exactly the same, if the polymer chemistry be more dangerous just because it's lipo or most of the mess known with lipo is due to the extreme applications that they are known to be used for (crazy high currents for small capacity, no bms, physical abuse etc.)

 

[BlueSwordM]

Pouch cells are inherently more dangerous than prismatic and specifically cylindrical cells due to their construction type.

However, what matters most in the case of a thermal runaway is cathode chemistry, voltage, electrolyte composition, cell lithium plating level and electrochemical degradation.

An LFP pouch cell at full charge will be much safer in a worst case scenario than a cylindrical LCO cell at full charge.

Same thing for voltages: even the worst LCO cathode will be nearly indestructible if kept at 0% SOC.

Electrolytes and additives also play a role, but that requires going over a cell by cell analysis; most manufacturers won't tell you anything about the specific electrolyte mix. You have to infer a lot of things from reading scientific articles.

For example, I've learned over the past few years that there are lithium salts that can be used in place of LiPF6 in LFP cells (LiFSI) because the lower voltage allows the use of less voltage tolerant, but safer, cell components.

 

[LewTwo]

Polymer doesn't refer to the pouch form, it refers to the type of electrolyte.
There are lithium ion (not polymer) in a pouch form also.

My question is if the specs and use are exactly the same, if the polymer chemistry be more dangerous just because it's lipo or most of the mess known with lipo is due to the extreme applications that they are known to be used for (crazy high currents for small capacity, no bms, physical abuse etc.)

I stand corrected ... at least partially. If i may quote Wikipedia: Lithium polymer battery - Wikipedia

A lithium polymer battery, or more correctly, lithium-ion polymer battery (abbreviated as LiPo, LIP, Li-poly, lithium-poly, and others), is a rechargeable battery of lithium-ion technology using a polymer electrolyte instead of a liquid electrolyte. Highly conductive semisolid (gel) polymers form this electrolyte.

....

The main difference between lithium-ion polymer cells and lithium-ion cells is the physical phase of the electrolyte, such that LiPo cells use dry solid, gel-like electrolytes, whereas Li-ion cells use liquid electrolytes.

The article goes on to state that LiPo may be a type of film that is 'soaked' with an liquid electrolyte or a 'gel'. This is similar to the differences between lead-acid batteries: flooded acid, gelled acid, and AGM (Absorbed Glass Mat). My point being it is a physical attribute rather than a specific chemical compound.

Several years ago I was interested in using LiPo cells because of their light weight. I researched cells/batteries from several major vendors but I was particularly interested in the chemistry. My personal experience (which goes all the way back to using lead-acid AGM aircraft batteries on my first E-Bike) had/has been that LiFePo4 has the best longevity of the various chemistries available at the time. They seem to be more tolerant of abuse both physical and electrical than other chemistries that I had personal experience with. However this was just at the time when LMO (Lithium Manganese Dioxide or LiMn2O4) were coming into the consumer market. I wrote letters to several (a physical letter is a form of communication that was frequently used in ancient times) major vendors of RC LiPo batteries that inquired about their base chemistry. They universally responded that the chemistry was proprietary information and would NOT be publicly revealed. As a result, I never purchased any LiPo batteries.

I believe most Lithium Ion cells currently manufactured use a similar construction method . That being sheets of various films (i.e. anode, electrolyte, cathode, separator) are layered together to form the cell. Sometimes these layers are 'rolled' to form cylindrical cells and sometimes these layers are 'folded' to form rectangular cells. Thus one could argue that all such cells are LiPo.

Justin Lemire-Elmore (Grin Technologies) gave a presentation earlier this year on "Grin's Perspective on Ebike Battery Fires":
His basic conclusion was that Quality Control of the battery construction is the biggest factor in E-Bike battery safety.

As far as I am aware: LTO ( Lithium-Titanium-Oxide) is the safest Lithium Ion cell chemistry available to consumers but it is also one of the most expensive. Does it come in the form of a LiPo battery ... frankly I do not know (see the first line of my signature below).

 

[rg12]

Pouch cells are inherently more dangerous than prismatic and specifically cylindrical cells due to their construction type.

However, what matters most in the case of a thermal runaway is cathode chemistry, voltage, electrolyte composition, cell lithium plating level and electrochemical degradation.

An LFP pouch cell at full charge will be much safer in a worst case scenario than a cylindrical LCO cell at full charge.

Same thing for voltages: even the worst LCO cathode will be nearly indestructible if kept at 0% SOC.

Electrolytes and additives also play a role, but that requires going over a cell by cell analysis; most manufacturers won't tell you anything about the specific electrolyte mix. You have to infer a lot of things from reading scientific articles.

For example, I've learned over the past few years that there are lithium salts that can be used in place of LiPF6 in LFP cells (LiFSI) because the lower voltage allows the use of less voltage tolerant, but safer, cell components.

Very interesting.
So it basically means that we can never know 100% what electrolyte mix and such we have in the cells we use in order to try and assume their safety from that information.

Back to my question since you seem to know alot of specific stuff
Do you think that in general, will there be a difference in safety between li ion and lipo considered they both share the same specs and are used under the exact same conditions? both pouch form, same capacity and internal resistance etc.

 

[BlueSwordM]

Very interesting.
So it basically means that we can never know 100% what electrolyte mix and such we have in the cells we use in order to try and assume their safety from that information.

Back to my question since you seem to know alot of specific stuff
Do you think that in general, will there be a difference in safety between li ion and lipo considered they both share the same specs and are used under the exact same conditions? both pouch form, same capacity and internal resistance etc.

If we only have differences in packaging, a cylindrical cell will tend to behave in a better safer manner than a pouch cell.

 

[rg12]

If we only have differences in packaging, a cylindrical cell will tend to behave in a better safer manner than a pouch cell.

No I mean If comparing li ion and lipo both in pouch form, same IR, C rate, Capacity etc and also the same testing under load.

 

[DogDipstick]

Very interesting.
So it basically means that we can never know 100% what electrolyte mix and such we have in the cells we use in order to try and assume their safety from that information.

Well, friend. thee is one way.

.....one way that is never wrong.


I know definitively the cell I use are 100%, LG, lipo. " Lithium Ion Polymer".... The pouches I use.. wanna know how?

I read the datasheet.


Incredibly safe, this model of cell is self healing, lasts years longer than retail grade lithium cells, independently tested by many safety companies... are highway tested under contin loading, and are sold by the millions. No short term danger of fire, or holes in the pouch, or heat, is going to create a thermal event. They are sold by a major manuf. to people who know not a thing bout a " battery" in the car they buy, they are dumb as a doorknob.

very safe ... they were made.

 

[NOTA]

Wifie said those things are right between your legs
not a good place for things that catch fire

I think the label li or li-po or li-ion
don't say if it can or will burn or the facts needed
is it MC or FeP and who made it WHERE
THE CELLS CHEMISTRY STYLE AND WHO
THEN ASSEMBLED THE PACK
IS THE MAKER A CHINA SWEAT SHOP ?
OR A REAL INTERNATIONAL CORP WITH STANDARDS

 

[gromike]

Wifie said those things are right between your legs
not a good place for things that catch fire.

If it's smok'n you best be go'n.

 

[Hillhater]

the cell I use are 100%, LG, lipo. " Lithium Ion Polymer".... The pouches I use.. wanna know how?

I read the datasheet.


Incredibly safe, this model of cell is self healing, lasts years longer than retail grade lithium cells, independently tested by many safety companies... are highway tested under contin loading, and are sold by the millions. No short term danger of fire, or holes in the pouch, or heat, is going to create a thermal event.

How different are these LG pouches, to those used in the GM Bolt etc ,…or the LG home Storage Batterys, …all of which are known to have major issues with unpredictable thermal events ?
All LG home storage batterys are currently under an emergency “ Do Not Use” recall notice !
And the Bolt packs were also recalled for replacement.

 

[gromike]

How different are these LG pouches, to those used in the GM Bolt etc ,…or the LG home Storage Batterys, …all of which are known to have major issues with unpredictable thermal events ?
All LG home storage batterys are currently under an emergency “ Do Not Use” recall notice !
And the Bolt packs were also recalled for replacement.

Link?

 

[DogDipstick]

How different are these L

IDK HH. From my one point of data, me, building packs for a few years, very safe. yes i know about the recalls, no I dont have any special info to tell me these have any relation to those.. but.. Chevrolet is still selling this. So I say its safe. they did the math, the safety studies, the numbers, stats, and data, points, and put it in a Chevy that wanst recalled, and rolled with it.

Cell is also found in Pacifica and the Zoe. So .. yeah . They had a good safety sheet for the OEM makers to choose them to meet the standards as they had to meet.

IDK me? Im dumb but mechanically inclined somewhat, have a tidy workshop, and am somewhat logical sometimes.. So it has worked out for me. they perform wonderfully, given my first experience with batteries was a 7.2V Nicad for the RC car and that took 30 min t charge for a 6 min run with dad in the church parking lot... This pack I built is just a little powerhouse that doesn't quit, is well behaved, and just chugs along summer after summer.

I will soon have bought more tires, than battery cells, for this ( 62mph) ebike, in its life.

I am well over two times the brakes pads, ( 40+, ) .. than the number of cells I had to buy three years ago. I purchased 2019 new cells in 2021.. NOS.

 

[Hillhater]

Link?

LG ESS Battery

www.lgessbattery.com

https://insideevs.com/news/532661/gm-lg-bolt-battery-recall/

LG cells also used in the Jaguar iPace EV which has also now has a total recall for battery fires..

Jaguar recalls I-Pace electric SUVs due to battery fire risk

General Motors, Mercedes-Benz, Hyundai, Stellantis and Volkswagen have issued recalls since February of 2020, most due to internal battery failures that can increase the risk of fires.

auto.hindustantimes.com

LG are a reputable cell manufacturer, but it seems they have had production quality issues, which due to the high volumes supplied have resulted in a disproportionate number of EV fires.

 

[gromike]

Thanks for the link Hillhater.
Kind of like the A123 and Fisker thing, but much bigger.