Dangerous MKEPA Li-ion Battery Pack

[avandalen]

I disassembled my 10S4P MKEPA Li-ion battery pack and found out that it is unsafe as the individual cells are directly glued together without the use of additional plastic spacers. This poses a considerable risk of short circuits. This vulnerability arises from the potential wearing down of the thin plastic film that encloses the cells, especially during vibrations experienced while driving.
Short circuit is dangerous and will cause fire or explosion.
Please give your opinion on this issue..

 

[leffex]

Do you have any experience with packs build in this way?

I have experience from packs with plastic 18650 moulds plus a bms and charge- and discharge fuse.

I have not seen any black spots or alike when doing checks.

 

[slaphappygamer]

I’m still learning about batteries. There is so much info to take in. What 18650 cells have a 5ah capacity?

 

[floydr]

What 18650 cells have a 5ah capacity?

None 3.5Ah is about the limit with 18650's
later floyd

 

[docw009]

I would prefer not to own batteries built in that manner, It's a long term reliability problem for an ebike pack, which is subject to mechanical stress and vibration. Less of an issue with a stationary battery, Yes, no glued cells for me,. They should be in a plastic cell matrix.

Another good practice is to use insulating rings over the positive terminals. Otherwise, the only insulation is the PVC wrap over the edge of the cell. It also helps protect damage, if the spot weld is off center.
,

 

[amberwolf]

FWIW, if the cells are actually securely glued together, and secured inside a casing that prevents it from moving around except as a whole entire unit, it's unlikely that vibration will cause any degradation of the shrinkwrap.

However, if any cell actually did fail in a way that heated it enough to cause the wrap to split (which has happened without actually causing a fire or any other failure than killing the group of cells it's in by discharging all the rest of the ones in parallel with the failed cell), and that heat caused the contacting cell(s) in the next parallel group in series with it (either + or -) to *also* split it's wrap, *and* those splits line up...*then* a short that can cause a fire could happen.

If the cells are not really thoroughly glued together, but just have some glue on some of the cells in each group of cells that's glued to the next series group, then vibration can have it's way with the ones not secured by glue.

Same for if the glue is a type (like hotglue) that doesn't really stick under some conditions and can crack and come off.

Also same for shrinkwrap that is either already damaged or is fragile and cracks under age or various environmental conditions the pack is likely to see.

Note also that if the glue doesn't securely hold the cells in place, and they can move even a tiny bit inside their casing, then over time the interconnects between cells that can move can fracture, usually at the spotwelds, and cells in groups can become disconnected from the pack, reducing the pack capacity and capability, and stressing the remaining cells in those groups, shortening their lifespan and heating them more in use than the rest.

 

[avandalen]

I’m still learning about batteries. There is so much info to take in. What 18650 cells have a 5ah capacity?

>> What 18650 cells have a 5ah capacity?
See here 4000mAh

Ultrafire Oplaadbare batterij 18650 4000 mAh (2stuks) - zwart | bol

Ultrafire Oplaadbare batterij 18650 4000 mAh (2stuks) - zwart. Ultrafire 18650 3.7V 4000mAh Rechargeable Lithium Battery - Black. Lithium-Ion batterij,...

www.bol.com

 

[avandalen]

FWIW, if the cells are actually securely glued together, and secured inside a casing that prevents it from moving around except as a whole entire unit, it's unlikely that vibration will cause any degradation of the shrinkwrap.

However, if any cell actually did fail in a way that heated it enough to cause the wrap to split (which has happened without actually causing a fire or any other failure than killing the group of cells it's in by discharging all the rest of the ones in parallel with the failed cell), and that heat caused the contacting cell(s) in the next parallel group in series with it (either + or -) to *also* split it's wrap, *and* those splits line up...*then* a short that can cause a fire could happen.

If the cells are not really thoroughly glued together, but just have some glue on some of the cells in each group of cells that's glued to the next series group, then vibration can have it's way with the ones not secured by glue.

Same for if the glue is a type (like hotglue) that doesn't really stick under some conditions and can crack and come off.

Also same for shrinkwrap that is either already damaged or is fragile and cracks under age or various environmental conditions the pack is likely to see.

Note also that if the glue doesn't securely hold the cells in place, and they can move even a tiny bit inside their casing, then over time the interconnects between cells that can move can fracture, usually at the spotwelds, and cells in groups can become disconnected from the pack, reducing the pack capacity and capability, and stressing the remaining cells in those groups, shortening their lifespan and heating them more in use than the rest.

FWIW, if the cells are actually securely glued together, and secured inside a casing that prevents it from moving around except as a whole entire unit, it's unlikely that vibration will cause any degradation of the shrinkwrap.

However, if any cell actually did fail in a way that heated it enough to cause the wrap to split (which has happened without actually causing a fire or any other failure than killing the group of cells it's in by discharging all the rest of the ones in parallel with the failed cell), and that heat caused the contacting cell(s) in the next parallel group in series with it (either + or -) to *also* split it's wrap, *and* those splits line up...*then* a short that can cause a fire could happen.

If the cells are not really thoroughly glued together, but just have some glue on some of the cells in each group of cells that's glued to the next series group, then vibration can have it's way with the ones not secured by glue.

Same for if the glue is a type (like hotglue) that doesn't really stick under some conditions and can crack and come off.

Also same for shrinkwrap that is either already damaged or is fragile and cracks under age or various environmental conditions the pack is likely to see.

Note also that if the glue doesn't securely hold the cells in place, and they can move even a tiny bit inside their casing, then over time the interconnects between cells that can move can fracture, usually at the spotwelds, and cells in groups can become disconnected from the pack, reducing the pack capacity and capability, and stressing the remaining cells in those groups, shortening their lifespan and heating them more in use than the rest.

Thank you for you help

 

[amberwolf]

>> What 18650 cells have a 5ah capacity?
See here 4000mAh

Ultrafire Oplaadbare batterij 18650 4000 mAh (2stuks) - zwart | bol

Ultrafire Oplaadbare batterij 18650 4000 mAh (2stuks) - zwart. Ultrafire 18650 3.7V 4000mAh Rechargeable Lithium Battery - Black. Lithium-Ion batterij,...

www.bol.com

Ultrafire :lol:

Sure...have you ever tested any of those *fire cells? (ultrafire, trustfire, etc etc) You might check out some of the various cell testing sites, such as lygte-info.dk, that have detailed testing of various cells including some UFs.

Not sure if they still do it, but they (and other *fire companies) used to re-wrap recycled garbage cells and sell them as new cells of impossible capacities that even the very best brand new 18650 cells could never reach. After that, I find it difficult to trust any of those *fire companies.

What makes it even worse is that there have been (probably still are) companies actually making fake versions of those already-crap cells (just like they also make fake versions of well-known good cells from reputable brands), using either even worse garbage cells rewrapped as them, or doing ridiculous things like this:

https://062085.p3cdn1.secureserver.net/wp-content/uploads/2014/06/bad-18650.jpg

 

[calab]

The majors need a place to dump their rejects.

 

[batteryGOLD]

Ultrafire :lol:

https://062085.p3cdn1.secureserver.net/wp-content/uploads/2014/06/bad-18650.jpg

View attachment 335620

good joke 18650 4000mAh..
the maximum capacity on a 18650 is 3400-3500mAh

Ultra fire and other joke brands adv up to 10000mAh in a 18650 (clickbait)..

the are some joke cells mass shipped worldwide. U get a 18650 with a half size cell inside, plus filled w beach sand to gain weight & safety..
smart ideia from seller?
at least the fire of risk/damage is less. 1Ah mini cell inside metal 18650 shield. soo safety is great! plus bonus fuse wires for 3A protect..
ultrafire means ultrasafety!

and careful w fake used cells with brand wrap . I have many LG HG2 bought at alixpress. twice IR and half capacity.. are U kidding?? waste of money! Only buy cells at trusted warehouses.

 

[batteryGOLD]

Imagine U buy fake LG H2 cells (with twice IR ) and put into a high drain veicule.
imagine it will pull out 10A from each P cell.

this will cause massive temperature increase for those fake cells..
passing 80 degrees celsius, cells enter tha danger temperature zone. soo it could happen tha perfect conditions for a nice battery fire show!
the more time U keep driving , the more heat is produced. after 100 celcius, those tend to fire ignition

Be carefull w increased IR and used cells! those tend to produce much more heat

 

[From-A-To-B]

I agree that manufacturers shouldn’t be allowed to make and sell batteries that cut so many corners — they are dangerous. Similarly, distributors shouldn’t pass along batteries without cell holders, etc. But as an educated consumer, we also have a role to play in protecting our homes, ebikes, housemates and neighbors. You bought a battery with 40 cells inside of it and paid 55 euros / $60USD. What did you expect to receive? Surely you knew better and did not expect a well-made battery with quality cells and better than average safety margins.

Let’s not support cheap-o resellers. Let’s also not get mad when cheap-o resellers sell you cheap-o crap. Most often, you get what you pay for, and YMMV.

 

[eMark]

Hot Glue vs Plastic Framed 18650 Packs : Which One Should You Buy / Build?​

Hot Glue vs Plastic Framed 18650 Packs : Which One Should You Buy / Build?

Whether you’re in the market for an 18650 ebike battery pack or you’re thinking to build one from scratch one of the big decisions you’re going to have to make is whether you&#821…

electricbike-blog.com

https://electricfatbike.files.wordpress.com/2016/03/img_20151222_0824557521.jpg?w=1024&h=576 ...
"Just because a pack is glued together does not mean that you should avoid it. There are plenty of glued packs out there that work very well in the designed power range. The problems start to crop up when you are ‘pushing’ the cells to the limit of their discharge capability on a regular basis. If the pack is getting too hot after every ride then you need to consider getting a pack that can put out more power without generating quite as much heat. Certain battery chemistries like the NCRb and the GA cells tend to get warmer than other chemistries like the 25R which doesn’t seem to get hot no matter how hard you thrash on them."

comment by Craigjs ...
"Fact is, proper cell choice will limit heat buildup in the cells, making the “hot inner cell” argument moot (as well as misguided). Glued cells may result in harder servicing but welded packs make that hard already. I’ve stopped using spot welding because I’ve found a better solution, one that results in better pack performance AND improves servicing more than frame vs. glue does."

"Personally, I value keeping packs small so I would never consider forms. I glue my packs, just not with hot melt. If I built giant packs like some do I’d probably rethink my approach. You have to look at the big picture."


Didn't both Em3ev and Grin at one time (or maybe still) glue cells together for smaller pack size?

 

[tomjasz]

Didn't both Em3ev and Grin at one time (or maybe still) glue cells together for smaller pack size?

Sure but how does that make it an acceptable method? Given the potential issues why would anyone spend good money on marginal builds?

 

[eMark]

eMark said:
Didn't both Em3ev and Grin at one time (or maybe still) glue cells together for smaller pack size?

Sure but how does that make it an acceptable method? Given the potential issues why would anyone spend good money on marginal builds?

"As to glueing the cells, my Em3ev 14s 9p triangle pack, was glued. It came without cell fusing, and died a quick death. At least it cost $1500 Canadian! I had a small pack from them" (by Phasedout - 4/29/23)

Your posts in that above ElecticBike article were insightful; especially this comment ...

"I dare anyone to go to ES and start ranting about Cellman’s (Paul at EM3ev) glued packs. Post the link, I’ll watch. NOW if you’re Karl, or Bruno, or anyone of the power users riding hard and putting it up wet with performance cells, and drawing maximum amps for most of your ride, pay attention and get those air gaps. But if you’re a majority of the casual riders, buy that quality cell, glued pack, and let the hot dogs sweat the heat." ...

 

[eMark]

I disassembled my 10S4P MKEPA Li-ion battery pack and found out that it is unsafe as the individual cells are directly glued together without the use of additional plastic spacers. This poses a considerable risk of short circuits.

Prolonged voltage sag is usually the culprit. If you can't afford to buy a more expensive quality battery to minimize voltage sag try the following: Shift down from say 5 to 3 and do some power pedaling assist up a lengthy hill climb.

This vulnerability arises from the potential wearing down of the thin plastic film that encloses the cells, especially during vibrations experienced while driving.

If that happens the culprit is inferior battery fabrication. Even if you added another shrink wrap tube over the can label the culprit is more often excessive heat that can burn a hole through the cell can. Either due to cheap Chinese blue shrink wrap batteries (e.g. AliExpress, Alibaba), inferior DIY using salvaged cells, human DIY error, prolonged voltage sag leading to excessive heat and potential fire.

There will still be professional builders that will glue to save time, cost and space. Whether or not it is "acceptable" depends on the quality of the cells and taking into account the particular battery application to minimize voltage sag.

Is Voltage sag damaging to batteries?

I recently added voltage meters to the bikes that I put together for my wife and I... After a few rides with them, it's clear that whenever you "get on it" the voltage sags around 3-4 volts - probably more at times. So if you consider 3.3 volts per cell to be the danger zone (42.9 for my 13s...

endless-sphere.com

Using the following plastic spacers may not prevent a fire anymore than gluing side-by-side when one or more cells overheat to the point of burning through the can wall ...

 

[tomjasz]

"As to glueing the cells, my Em3ev 14s 9p triangle pack, was glued. It came without cell fusing, and died a quick death. At least it cost $1500 Canadian! I had a small pack from them" (by Phasedout - 4/29/23)

14s9p a small pack? And how does early adopters using glued cells make it an acceptable standard? you’re looking to take a piss again. well at least this time you’re not trolling my wife’s facebook page. that’s a relief…

 

[eMark]

14s9p a small pack?

You'd have to ask Phasedout. He is possibly referring to another pack that he purchased from EM3ev ...

"As to glueing the cells, my Em3ev 14s 9p triangle pack, was glued. It came without cell fusing, and died a quick death. At least it cost $1500 Canadian! I had a small pack from them" (by Phasedout - 4/29/23).

Apparently he had an unforunate experience with his 14s9p Em3ev (raw performance instead of casual use?).

And how does early adopters using glued cells make it an acceptable standard?

Apparently it used to be acceptable and still is used when frame space is too limiting as long as usage is casual to moderate with only brief bursts of a few seconds ... instead of prolonged raw performance ebiking.

well at least this time you’re not trolling my wife’s facebook page. that’s a relief…

That was a compliment your fb friend on her beautiful scenic photograph of the Mississippi River bluffs as seen from near a cabin. Also that professional drone video of your city. You PMed me saying it made your day. Her last name began with a "Q" so how was i to know she was your "wife". Besides it was a compliment of her photo skill.

In the following comment of yours you listed your first and last name. So did a quick search to see in you have a fb page. Your following post implies you only apporove of cell glueing when space is limited for casual ebiking, but not for raw performance even with quality cells that could overheat from continued raw performance ebiking enjoyment ...

"I dare anyone to go to ES and start ranting about Cellman’s (Paul at EM3ev) glued packs. Post the link, I’ll watch. NOW if you’re Karl, or Bruno, or anyone of the power users riding hard and putting it up wet with performance cells, and drawing maximum amps for most of your ride, pay attention and get those air gaps. But if you’re a majority of the casual riders, buy that quality cell, glued pack, and let the hot dogs sweat the heat." (June 17, 2016) ... Hot Glue vs Plastic Framed 18650 Packs : Which One Should You Buy / Build?

Your axe griniding is still apparent and ill-conceived. It accomplishes little as others may begin to realize that your account is just as likely or more likely a false narrative that needs to be refuted. Your false accusations have no place in this thread or other previous thread(s) or future threads.

 

[tomjasz]

That was a compliment your fb friend on her beautiful scenic photograph of the Mississippi River bluffs as seen from near a cabin.

nice try. you spent by your description and post that you spent an inordinate amount of time figuring out and searching to find my personal information and then found my wife, who has her maiden name and her Facebook page. that's creepy and the epitome of a creepy troll. and old creepy troll. ffs who does that? you! and its creepy.

a creepy one build self declared expert. sad very sad...

I should post your creepy pm's but you're to weird to bothervwith and sensible readers get how creepy that was.

 

[eMark]

Noticed you just recently decided to delete two or your three previous posts including the one previously posted in that "ElectricBike-Blog.com" article. It took you long enuf (8 years) to finally decide to delete 2 of your posts. Notice you also deleted your first and last name from the one remainig post. Didn't want anyone to lookup your fb page?

"I dare anyone to go to ES and start ranting about Cellman’s (Paul at EM3ev) glued packs. Post the link, I’ll watch. NOW if you’re Karl, or Bruno, or anyone of the power users riding hard and putting it up wet with performance cells, and drawing maximum amps for most of your ride, pay attention and get those air gaps. But if you’re a majority of the casual riders, buy that quality cell, glued pack, and let the hot dogs sweat the heat." (June 17, 2016) ... Hot Glue vs Plastic Framed 18650 Packs : Which One Should You Buy / Build?

It's time for you to STOP and MOVEON from your ill-conceived faulty version. Your dull axe grinding rant has nothing to do with whether or not, OR when to buy a glued pack. Agree that your above post was apparently acceptable thinking in 2016 ... you still aren't far-afield. However, for whatever reasons you decided to delete it.

Happy trolling off a sand bar for a few sauger (sand pike) and pulling it its famous cousin ...

 

[Comrade]

This is how a battery made by a company you can sue looks like.

 

[tomjasz]

sad little troll you are. life and learning is dynamic and ever changing. except for sad little trolls that search out es members wives Facebook pages. your trolling skills are waning. nothing is deleted. sad very sad.

 

[eMark]

Your whinning about a PM in this Battery forum has nothing to do about a "Dangerous MKEPA Li-ion Battery Pack"
Can you not find something that's more productive like bottom trolling to catch a sauger or walleye in Mississippi R.

By the way that youtube i came across (by chance) a few weeks ago of you as Chief Horticulturist was interesting. Your a handsome seasoned guy, nice voice quality and facial expression all adds up to showcase your special talent-gift that made for an excellent presentation ... Very Well Done!

 

[tomjasz]

Your whinning about a PM

creepy, period. by your own admission you spent and inordinate amount of time sorting and searching out my identity. Then while still never identifying yourself sent me photos from my wife's Facebook page. FFS man if that's not creepy.