Please someone want a monster 26lb pack…
Really good for a bike I bet.
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@Battery_Mooch What kind of real numbers could I get from this?
How do these prismatic cells compare in terms of safety, the alternative is me building with NESE modules? Can prismatic cells like these handle vibrations?
It would just fit as a top mounted enclosure on a MTB, or failing that I’m planning a ebike, is this a terrible idea?
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These have metal on the outside which is dope for protection and mounting. Can’t really get easier than these, besides the possibility optional BMS installation and having the get output wires with hopefully a fuse made.
I have no idea. 
You’ll have to check the claimed ratings and search for those who have used them.
Prismatic cells come in many different battery “chemistries”. LiFePO4 (LFP) is the safest but is not “safe”. You still need to respect the power they have.
BH doesn’t say they are LFP so they seem to be standard Li-Ion cells, same chemistry as the round cells we use. Check with BH to be sure though.
Not any better than round cells but it completely depends on how much vibration reaches the cells themselves. A metal frame mount can absorb shock/vibration or just pass it right on through to the cells. You’ll have to dive into how that module is constructed to see what it can/can’t do.
I don’t know if there was additional shock/vibration protection that module was mounted in or if the protection exists as part of that module. I haven’t looked at it for more than a couple of seconds.
Not at all!
The devil is in the details though. The mounting and protection (electrical and physical) you give the pack, like for any pack, is critical.
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Seems prismatic are better with shock/vibration and cylindrical are better laid on their side.
https://journals.sagepub.com/doi/full/10.1177/14613484211008112
Causing internal short circuits. Yikes.
I imagine no bms will save you from a fire if an ion cell internally shorts. Makes me feel even better with lifepo4. Anyone know where u could get A123 cells for a buck? 
I further imagine a skate deck may be one of the harshest environments in this regard.
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For that first paper…
We have to be careful when using research papers, they are typically quite specific in where their conclusions can be applied.
That paper mentions pouch cells. We don’t know if prismatic cells are similar enough to have the same advantages and disadvantages and prismatic cells from different manufacturers, in different hard cases, can have different strengths and weaknesses.
Their warning against the use of mandrel-containing round cells in certain orientations is a good one but there are very few cells with mandrels (the LG HG2 is one). Most are solid internally and are not as susceptible to vibration as the ones with mandrels.
Vibration and shock are to be avoided though, it’s never a good thing as no cell is designed to handle it alone.
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Agreed!
That second paper was great, thanks for the link!
They tested, and warned against, the use of mandrel-containing 18650’s but tests on other 18650’s (some presumably without mandrels) show that vibration/shock can accelerate the aging of a cell and/or damage it badly. No one should be surprised by this but it’s great to see some hard data on it.
Bottom line folks….protect your packs if you care about them lasting!
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I assumed all the cylindrical cells were wound on a mandrel or something. What is a solid cylindrical cell or can u explain the different physical designs?
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I’m guessing that all are wound on a mandrel but many have the roll of stuff pulled off the mandrel as it’s put into the can…maybe all of them.
The only way the bottom spot-weld can be made is if the electrodes can go down the middle of the cell and a mandrel would get in the way of that. I’m guessing that if a mandrel is used that it’s added after the bottom spot welding is done.
All 18650’s have a bit of space at the top and bottom of the roll of stuff so that provides an opportunity for movement if the plastic insulating/padding disks at the top and bottom don’t completely fill the space.
Checking out some x-rays of cells will explain things a lot better than I can with words.
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Just a side note…the mandrels in li-ion round cells are tubes, not solid. They’re used to keep the cell’s stuff from clogging up the central core opening when the cell is in thermal runaway. The tube allows gas to escape from the bottom of the cell instead of, possibly, allowing the pressure to increase enough to burst the cell.
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This is some really good info on the effects of vibrations, it’s got me looking into mandrels and stuff. Here’s a screenshot of a youtube video, and it’s got a source in the bottom right corner that might have more data on which cells have mandrels.
The A123 battery model listed there is not one of the 2 listed for sale on the a123batteries website. I’m not sure if they’re built the same way, but maybe it’s a good idea to lay them horizontally when building packs?
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Unfortunately that source is a purchase-only paper. 
I’m confused by that screen-captured table as every HG2 I’ve seen opened up has had a mandrel. Perhaps they don’t anymore.
This might be good advice for any cell since we might not be sure if they have mandrels (or not).
But only if we can confirm that there is minimal lateral shock/vibration. Or at least, a lot less than what they would experience if positioned vertically.
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Weird about the HG2 cells. I guess it’s hard to trust or translate scientific papers. If you want to read it though, you can use this link and click “view open manuscript.”
I poked around it a little bit, and it confirms that “The axial direction is the most severe.” (Axial is vertical when the can is standing up.) “The six cells which were reported to show more than 200% rise in ohmic resistance…”
For that info they actually cited the study Hummieee linked above.
It also says “the mandrel has been the most critical component in [the study Hummieee linked], causing damage in the jelly roll and of the negative current collector tab.”
But then check this out:
“All four cell types show jelly roll deformations, most prominently in the Samsung INR18650-25R in Fig. 3b due to the absence of an inner mandrel”
So idk if mandrel good or bad, but it seems like all cells would be better off not vibrated vertically. Then again, Tesla packs all have vertically-oriented cans…
I agree that other tests would need to see how much lateral vibration there is on say, a top-mount mountain board pack, but I’m guessing that it won’t outweigh the up and down shocks. I wonder if aiming the cells lengthwise down the board or perpendicular to it would be better? Also this has me thinking about prismatic cells, which are what Tesla is currently using in their LFP packs.
Also sorry if I’m diving too far into this and derailing this thread about batteryhookup website lol
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Thanks for the link.
Yea, about the only thing we can definitely take from all this is that vibration is bad. 
we now return you to our regularly scheduled thread…
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I imagine the vibrations on Tesla cells is small with the car suspension.
I still don’t understand why Tesla decided to continue on that path of a thousands cylindrical cells. Surely it costs more to produce per kilowatt and then the work of assembling and then while there’s a lot of safety built in there’s also a lot more potential failures.
Buy my 26650s for $1 each!
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At this point “surely” you would be saying the opposite
They produced nearly 1 million vehicles in 2021. They’ve been doing something right. At the same time, half of the purpose of moving to the new 4680 cells is so they can make structural batteries, and be more efficient.
I don’t think there is another option that is even close to what they have on the market today.
Yeah, siphoning off public funding and focusing on cult of personality and Brand Elon in a glorified confidence scheme
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I’m forgetting this new direction and just thinking of the many thousand 18650s they were using. And they’re now going bigger and that makes more sense to me looking from my perspective. Structural batteries sounds like the ultimate and all the extra metal needed to encase a battery seems a waste
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Yeah the goal with the new batteries is to work them into the actual chassis of the car - reduces replaceability by a lot but it makes the frame more rigid and can reduce the weight of the car, as well as increasing the ability to efficiently cool them.
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offtopic for this thread, but elon or not, the cars are unmistakably good cars.
They have flaws yes, but they’re still better than 90% of the rest of the electric car market.
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