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Rounded nickel strip controversy

found this in a PDF while googling. There are actually two more type of resistance welding but they have nothing to do with our use cases:

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Series welding is also known as parallel welding, which is a mindfuck for battery builders lol

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I’ve definitely sliced myself on nickel strip (tearing a pack apart), but battery pack blowing because you didn’t nip the corners… that’s funny.

More relevant, I like the strips with slots since you’re guaranteeing that current isn’t just shunting through the strip instead of your nugget:

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It’s not funny at all if a 500Wh pack blow up in your flat…or burn down your new 2000$ board on which you spend weeks to build it out.
Even if it’s just 1% likely that it can cause a short… it’s still could be your lucky day.
It’s like with a lot of other things.
I always wear a helmet.
How often I crash on my head when i‘m riding? Maybe ones out of 100 rides…and even than it’s not said that it’s a hard impact which could hurt me, but still I wear a helmet because I want to ride also tomorrow and not only today…

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Let’s agree on something.

Yes you can get away with sharp edges

Yes it’s better to round the positive side

I dont think anyone would argue with logic? Everyone goes out and makes their own choice. I personally choose the safest option.

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Totally agree with this.

But it’s not about how you or I build our packs. It’s about people who just start and maybe don’t make everything right from the beginning.
Every pack will vibrate if it’s not glued into the enclosure.
How much of our experienced builder here just velcron there packs to the deck…and how much really glue or silicon everything fixed in the enclosure like @sender does? :tipping_hand_man:

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You know we have the battery builder club.

I would appreciate if you have a free minute one day to add there some of your battery building experience so that others can take those as inspiration and example for there pack.

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Ok i think we came with this point to an agreement like @Brenternet perfectly summarized.

Let’s start another discussion:

is a fishpaper ring on the positive terminal really needed?

I mean, cells nowadays come all with a plastic isolation ring plus heat shrink on the outside of the positive terminal.
Which advantages does an extra fishpaper ring bring on top of it?
What’s the negative effects of not doing it?

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Same principle Andy. Better safe than sorry. As for the quality of the plastic rings and shrink? Not great on 30q cells. Removing a 30q cell from a vape to charge wore through the shrink and plastic in a month and caused my wifes one to vent and fuck off round the room. Vibration from an esk8 would replicate that amount of wear in a pretty short time in a badly built and installed pack

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On the other hand, I’ve got some 30Qs which have been in pretty much daily use since they came out, maybe 3 or 4 years ago, which are fine.

I guess it depends on your mod, and perhaps just as importantly, your charger, and how you install and remove your batteries.

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For me it’s really all situational. Usually I’ll cut the corners on 18650’s, but 20 and 21700’s typically line up well with the strips i use. I also cut the corners if the pack is gonna be squeezed into a tight spot or if the nickle edge is too far over the positive bridge.

It takes you 5 minutes to put it on the whole pack, and the fispaper itself is 2$

Easier just to put it on have extra safety and not overthink about everything like you do :smiley:

I‘m not overthinking everything :thinking::joy:

same for cut corners. It’s not so much more work, so why not…

But as we have this nonsense thread, why not to discuss this here as well.
Looks like as min one big vendor don’t see a need in the fishpaper rings :tipping_hand_man:

I disassembled like 5 different brands of cordless drills lawn mowers etc and none used fishpaper rings

I would just recommend using it because it gives a little bit extra safety and doesnt not cost anything

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i was melting that plastic ring with fast welding. The nickel strip would sink right in to the plastic. Not enough to trigger heat shrink tearing or enough to drop all the way through the plastic and short immediately, but it was definitely sinking into it.

Fish paper rings not only don’t melt, they insulate the immediate heat spike from resistance welding from the rest of the cell, forcing the heat to dissipate down the nickel instead, reducing the total amount of heat coming from the weld location.

TL;DR they keep the heat where it needs to be and not where it doesn’t, and in that way help prevent shorts.

i started using these rings 2 years ago and since then i’ve seen the packs last longer with fewer issues.

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Why wouldn’t you do your best to minimise the risk of your battery exploding/combusting?
Is the risk of burning your house down worth skipping a few itty-bitty tiny-winy safety measures that take you like five extra minutes?

At least use marshmallows or popcorn to pad your enclosure and the components within, so when it does go up in flames you’ll at least have something positive to celebrate with later.

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Good one!

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Ask the vendors which doing like 20-50pack in a row. Every extra step takes time and that add up.
Not saying it’s good, just think that’s the reason why.

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I’m not building that many packs but I can say I do round corners and do a lot of insulating on my packs and it puts a good 20-30 minutes into the build time.

I cut strips round only when necessary. I do not cut all of them. I use gaskets, barley, kapton, pvc shrink and eva foam. Imho it’s a huge waste of time (and conductivity) rounding them all. Protecting the balance wires is way more important and productive. Just my opinion…

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I round all my strips because it makes sense to me to not have any sharp corners anywhere.

Even if it is in a position where it doesn’t matter, it still looks better and more professional. It is an easy step to complete, and with a good tool like the Corner Chomper is also pretty quick.

Fishpaper rings are also an easy step and provide a great level of protection in my mind. I think you would be mad not to use them. I use these ones in groups of 9, they save heaps of time.

AU $1.63 16%OFF | 1sheet 9 Lithium Battery, Highland Barley Paper 9 Section 18650 Lithium Battery Insulation Pad Pack
https://s.click.aliexpress.com/e/rV58zyp6

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