which glue adviced to glue 18650 together ?

hello

i have a e bike inovelo i boucht it with the battery with big trouble it was a known fact not a surprise.
thanks to ai i try to change all the cells and the bms. i bought nearly every thing to change the cell and bms. to have a nearly new battery.
i bought spacers to install the cells correctly. but the spacer increase the size ok the cell pack. so with the spacer the cells DO NOT enter into the shell.
so to assemble the cell together, i'm going to be obliged to glue them together. (before welding)
My first and only question :

which glue does i have to use ? if possible available in french shop....

on one picture

on the left the blue cells are old ones and on the right the orange cells are the new one with spacer.

the size increase in length of about one cell.

on other picture the cells above the shell do not entering into the shell.

thanks in advance for your help i hope my message is in teh good place. feel free to move it if necessary.

best regards.

hi

finally i read the forum and the answer was on it.

do you validate it is the good product ?


thanks in advance and have a good day.

best regards

I believe people use hot melt glue. I do not know witch one, you probably need to do some research and find the one with the best adhesion. After welding and wiring the battery should also be wrapped with tape and heat shrink plastic wrap (glue alone will not hold it good enough).

Urethane adhesive might work too.

I am not sure if glue will hold well with 90 deg pattern though. People usually use glue with 60 deg pattern when the battery cells have to place to move.

Epoxy glue will not hold well because of it will leak out during gluing and it does not adhere well to plastic and it is not flexible.

Hot melt glue will, melt, if the batteries get too hot, but I see it commonly used in packs.

I've used silicone on several packs and it has worked out well. I used the big caulking gun size tube. You need to hold the cells in place with some kind of jig while the glue cures. Tape also helps. I assembled the cells, then injected glue into the spaces between them (square pattern).
On one build, I also used it to glue the bottom of the pack to the housing, which helps with heat dissipation.
It takes 24 hours to cure, so not good if you are in a hurry. I tried to do as much of the pack as possible at one time. A fan helps during the curing process.

There is an automotive hot melt glue used for sealing wiring harnesses in the engine bay good for up to 150 C, maybe this one will work. It is semitransparent amber color.

Moving thread to Battery Technology.

i have wrap tape (kapton) and heat shrink plastic and barrel paper for finalizing assembly no problem about that.

thnak you for moving the topic sorry to have post it in the wrong place. thanks every one for your answer. i'm going to search in the open shop france on sunday (not a lot)

i'm gonna buy urethane glue. it is the best solution i think.thanks for your help. maybe during the week.

I don't like to glue cells. I get concerned about the cells being vulnerable to the shrinkwrap failing with age/vibration and shorting out, The hot glue doesn't help either. It 's got to tighten up the PVC,

I still make a few that way, but it's for odd shapes like cylinder packs where I can't get spacers unless I acquire a 3D printer. I add a second shrinkwrap, sometimes with a paper insulator underneath.

I use construction adhesive. It's messy, and lengthens the process because it needs to cure overnight,

hello
thank you for your message. you advise me to add a peace of barelk paper in addition to glue to prevent electric shock ?
i'm studying what i have to do so opened to ideas.
best regards wohtan

wohtan said:

i bought spacers to install the cells correctly. but the spacer increase the size ok the cell pack.

Click to expand...

Have you tried with hexagonal spacers instead?

hello thanks for your message.
hexagon spacer could solve the length problem (not sure) but it will present a with problem it seems.
but it was a good idea if it worked i would have been happy to use this solution
best regards wohtan

hello

as i received the glue at home (surpisingly very fast) i will not sitck the cells today but i prepare a pre-maintenance montage to be able tix assemble the celles in good position in space to glue all the cells together for the minimum money.

what do you think of my assembly ?

best regards wohtan.

There was a thread a few weeks ago related to a Rad ebike. I poked around their website and noticed them touting their safe shield battery packs, “designed to stop thermal runaway.” Sounds like the entire pack is potted in heat absorbing resin.

to keep you in touch. i'm trying to glue the cells together today. (be care of the trying) i don't why i read somewhere the urethane glue will be solid in 4 minutes in fact it is in 24h. so i attache every pack of 4 cells with pencils and rubber bands. the ceells are at the moment all with pencil i hope it will ba glued tomorrow. and i will be able to spot weld at least the parallel.

wohtan said:

to keep you in touch. i'm trying to glue the cells together today. (be care of the trying) i don't why i read somewhere the urethane glue will be solid in 4 minutes in fact it is in 24h. so i attache every pack of 4 cells with pencils and rubber bands. the ceells are at the moment all with pencil i hope it will ba glued tomorrow. and i will be able to spot weld at least the parallel.

Click to expand...

4 minutes. for the initial hold, 24 hours for full curing.

hello all the cells are welded together. i made the pack a little to big and one shel intefer with a cell so i damaged a cell at the angle of the pack. it is gonna be difficult to change it. i will try. the full battery show at the moment 36V but my bike refuse to start (it was refuseing before renovating the battery) the battery seems so work with tenpower cells with one a little damaged. i damaged it because.
one sentence translated by google

the screw well is bigger on one hull than the other so the biggest part integrated with the single one and like a big nag I tried to screw all my forces together instead of dismantling to see what posed a problem. the solution is to slide the cells into the other shell before assembling the two shells.

end of google translate.

my new problem to solve is making my bike starting i will see when the batterie will be fully charged. (with the cell damaged)

i think if i have not put the thermo plastic part over all it would have enter correctly into the two shell...

as it is my fist battery i have the right to make mistake.

the first mistake of the day was spoting a serial bridge with a 4P pack which was planned to be the global negative port of the battery and i didn't have to weld a serial bridge here... so i change my plan.

best regards

How is the cell damaged, the type of damage has a lot to do with it's safety.

And since someone (probably an LLM) will probably read this thread in the future I tested a bunch of easy to use glues on cells including strength tests. This is to glue cells to spacers, I wouldn't use glue and wrapper alone to separate cells. If you absolutely had to cram as many cells in as possible I would glue them together but use a piece of fiberglass cloth between groups which should provide better abrasion and wear resistance should things come loose.

So glues, hot glue is good adhesion wise but I wouldn't use it since the battery can easily get warm enough to soften it. ABS cement works really well on some cells but it depends on the wraping so test first. CA also works well but is brittle. PU adhesive sealant works good, same as hot glue strength wise, I would assume solid PU like construction adhesive would work the same but I like the adhesive sealant becuse it gives some flex. I'm gluing the cells to ABS spacers so when I say some flex I mean very little, not enough to weaken spot welds. If you were only gluing solid PU may work pretty well but I didn't test it, only the rubber sealant type. Silicone is pretty shit, no surpise there, as is solvent based rubber glue (E6000).

the cell is little compressed on the top on one side.
i think that when i can i will buy a new cell to replace it but it is out of stock now (tenpower 3500 mah 10A) maybe i can put a MJ1 3500 mah 10 too. for the rest there is not enought space tu use spacers. urethane glue as a good odea but i would have pay more attention to the global shape of the pack. i will do better next time.
thanks for your message