what is the consequence of non pure nickel

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May 18, 2018
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hi i search a kit that has battery case, holder and presloted nickel

i would choose a 70 cell to be sure that a 13s4p fit with the bms.

the nickel i look is non pure,
what does that imply for futur?

aestical problem or fonctionnal problems?

iwould of course prefere purenickel
 

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Functional metal.
Any venting that a cell can potentially do will corrode the steel under the nickel plating.
Any fingerprints will corrode the steel under the nickel plating.
After corrosion starts, heat builds up in the area and more corrosion starts until it burns through.
Always use pure nickel. Test with some sanding and immersion in salt water for 48 hrs.
 
RootedSuperuser said:
Any venting that a cell can potentially do will corrode the tin under the nickel.
Any fingerprints will corrode the tin under the nickel plating.

Tin has nothing to do with it. I think you mean steel.
 
If you mean nickel plated steel, the real problem is actually the very poor conductivity of nickel-plated steel compared to pure bare nickel metal.
Carbon steel (1010) is less than halve than the conductivity of nickel.
Stainless steel is a tenth of the conductivity of nickel.
Nickel is already not that good a conductor to begin with (but convinient for spot welding). Copper, silver, aluminium are much better conductors.

See this reference table (Matador table):https://endless-sphere.com/forums/viewtopic.php?f=14&t=99968&p=1468205&hilit=Matador+table#p1468203

So if you pull substantial current, the nickel plated steel can become red hot, melt and cause a big fire.

Matador
 
so is this exact
Any venting that a cell can potentially do will corrode the steel under the nickel plating.
Any fingerprints will corrode the steel under the nickel plating.
After corrosion starts, heat builds up in the area and more corrosion starts until it burns through.

?
 
Heat will be generated from the non-correded but intrinsequely high resistance nature of steel strips. Poor conductivity of this type of metal yeilds to metal turning red hot (heat) when current is past through them.

P = R x I²
(Ohms law),

where P is the power (in watts) dissipated as HEAT by the metal strip, I² is the current squared (in amps²) that passes through the strip, and R is the resistance (in Ohms) of the metal strip itself.

The higher the resistance of the metal strip, the more heat it will produce under load. For same thickness, width and lenght of metal strips, resistance will be 10 times higher for stainless steel strips than for equivalent nickel strips. Consequently, heat will also be 10 times higher.
For 1010 carbon steel strips, heat will be two times higher than for equivalent nickel strips. Check the resistance tables I posted above, it gives resistance of strips per meter used, for various metal types, width, and thickness.

When the heat is sufficiently high to exceed the metal's capacity to dissipate heat (via IR radiation, convection and conduction) into surrounding environnement, the metal strip turns to an iron red color and melts. This could result in a potential fire.

Matador
 
If we are at the point of talking about cells venting or leaking electrolyte, then you got bigger problems to worry about than your metal strips.
 
Matador said:
If we are at the point of talking about cells venting or leaking electrolyte, then you got bigger problems to worry about than your metal strips.

what do you mean by this comment . where does cell venting or leaking electrolyte comes from in this post?
 
want to build said:
Matador said:
If we are at the point of talking about cells venting or leaking electrolyte, then you got bigger problems to worry about than your metal strips.

what do you mean by this comment . where does cell venting or leaking electrolyte comes from in this post?

Exactly.
 
want to build said:
so is this exact
Any venting that a cell can potentially do will corrode the steel under the nickel plating.
Any fingerprints will corrode the steel under the nickel plating.
After corrosion starts, heat builds up in the area and more corrosion starts until it burns through.
?

I was refering to your previous comment, since potential venting and corrosion seem to be of concern (electrolyte leak can also cause cell and strips corrosion, and if the cells vent it's very likely they will simultaneously leak electrolyte, as they contain a substantial amounts of it).
 
But ultimately, what I'm saying is:

Sure it's possible that corrosion between the cell terminals and the steel strips eventually develops. And sure that corrosion could add a bit of resistance to the current path and create a bit more heat.

But the real immediate problem is the intrinseque resistance of the steel strip itself which causes heat. This problem will occur well before any corrosion sets in. It will manifest the very first time you run your battery under load, well before any corrosion has time to set in.

Eventually though, corrosion could become another additional problem on top of the first problem. And to make matters worst, the heat from the high resistance will also accelerate corrosion if the steel strips have not yet melted (that depends on the amount of current you pull out of the battery). Metals corrodes faster under high temperatures, due to laws of thermodynamics.

Matador
 
Electrical conductivity and thermal conductivity in metals are closely correlated. The same qualities that allow you to resistance weld effectively cause, well, resistance. No big deal if you’re making a ham radio pack or a household powerwall, where energy content is much more important than power density. But for us, it’s a constraint. Who cares if your cells are good for 20A, if their interconnects are only good for 5A? And what good is using higher ampacity strip, if the heat required to weld it damages the cells?

The moral of the story, for me, is that you don’t have to use flashlight batteries to power your e-bike. Somehow we knew this 25 years ago, but many of us have forgotten.
 
Balmorhea said:
Electrical conductivity and thermal conductivity in metals are closely correlated. The same qualities that allow you to resistance weld effectively cause, well, resistance. No big deal if you’re making a ham radio pack or a household powerwall, where energy content is much more important than power density. But for us, it’s a constraint. Who cares if your cells are good for 20A, if their interconnects are only good for 5A? And what good is using higher ampacity strip, if the heat required to weld it damages the cells?

The moral of the story, for me, is that you don’t have to use flashlight batteries to power your e-bike. Somehow we knew this 25 years ago, but many of us have forgotten.

Hi tx
im not sure to understand what you mean by that that you don’t have to use flashlight batteries to power your e-bike.

So in understand that it is a really good idea to go pure nickel.
now, Since i want to use the holders and battery case similiare to the one on the picture, do you guys know if there existe a pur nickel metal sheet like on the picture at beginning? I would really apreciate some links if you have some cause i m stucked there.
i imagine i would put 2 sheets one of top of the other since i want to give the case enough conductivity to exploite my vtc4 13s 4p
for future hungry motors.( im building a long term battery)
 
want to build said:
Balmorhea said:
The moral of the story, for me, is that you don’t have to use flashlight batteries to power your e-bike. Somehow we knew this 25 years ago, but many of us have forgotten.
im not sure to understand what you mean by that that you don’t have to use flashlight batteries to power your e-bike.

Those 18650 cells are scaled correctly for a pocket flashlight, a vape pen, or a cell phone power bank. Not for a bike.

Get used to the idea that your pack’s performance is limited not by the cells, but by the nickel strips. If you need more than 5A continuous current per cell, you have to add more cells until you get there. Or you have to double up the nickel strips, with the understanding that more cell welding equals more cell damage.

One of the packs I use, which I built, is 25Ah cells in a 13S 1P arrangement. Those cells are rated for a maximum 500A discharge. The other pack I use, which I also built, is 20Ah cells in a 12S 1P arrangement. They’re rated for a maximum 180A discharge. (I only use 35A controllers with either one.) Anyway, they’d be crippled by nickel strip interconnects if they had them.

EVs can benefit from EV batteries. Give them a try, if you can.
 
Balmorhea said:
want to build said:
Balmorhea said:
The moral of the story, for me, is that you don’t have to use flashlight batteries to power your e-bike. Somehow we knew this 25 years ago, but many of us have forgotten.
im not sure to understand what you mean by that that you don’t have to use flashlight batteries to power your e-bike.

Those 18650 cells are scaled correctly for a pocket flashlight, a vape pen, or a cell phone power bank. Not for a bike.

Get used to the idea that your pack’s performance is limited not by the cells, but by the nickel strips. If you need more than 5A continuous current per cell, you have to add more cells until you get there. Or you have to double up the nickel strips, with the understanding that more cell welding equals more cell damage.

One of the packs I use, which I built, is 25Ah cells in a 13S 1P arrangement. Those cells are rated for a maximum 500A discharge. The other pack I use, which I also built, is 20Ah cells in a 12S 1P arrangement. They’re rated for a maximum 180A discharge. (I only use 35A controllers with either one.) Anyway, they’d be crippled by nickel strip interconnects if they had them.

EVs can benefit from EV batteries. Give them a try, if you can.
does ev means electic vehicule if yes what is the meaning of saying this?

when you say cell welding equals more cell damage. I find this to be only true with soldering tin lead kind of stuff.
on video i saw on youtube with spot welding there is almost no heat probleme since it is so quick . if you have info that says spot welding damages plz let me know
 
want to build said:
Balmorhea said:
EVs can benefit from EV batteries. Give them a try, if you can.
does ev means electic vehicule if yes what is the meaning of saying this?

when you say cell welding equals more cell damage. I find this to be only true with soldering tin lead kind of stuff.
on video i saw on youtube with spot welding there is almost no heat probleme since it is so quick . if you have info that says spot welding damages plz let me know

Yes, I mean electric vehicle batteries.

Ask yourself this: if you put sheet metal as thin as what's on the outside of an 18650 cell flat on the palm of your hand, and then spot welded nickel strip to it, would your hand be damaged?
 
Hi youre examble is not so good cause of lots of factor mass and etc. anyways, a part from what you imagine do you have something to support this,? cause on the other hand lots of vid show that welding heats very little the cells. i appreciate your comment im just trying to rely on xp or facts.
 
The inside of the cell is very thin layers of moist chemicals and plastic films. If you don't think cell welding harms those materials, you're fooling yourself.
 
want to build said:
welding is still less damaging than soldering isnt it .
what do you suggest than

Sure, welding is faster with less total heat.

My suggestion is use cells that have threaded posts or at least tabs that didn't have to get welded on to begin with. Like, not flashlight cells.
 
second language here
what is a tab in this universe ebike?


and is a threaded posts a conversation with a lot of answers exchange?
 
want to build said:
second language here
what is a tab in this universe ebike?

and is a threaded posts a conversation with a lot of answers exchange?

Tabs:
images


Threaded posts:
s-l400.jpg
 
want to build said:
hi tx for the image

what do these 2 do?

the second is a special container for 18650 right?

It's a cell. Like an 18650 flashlight cell, but 25Ah. You don't have to weld it, because it has terminals that you can clamp to directly.

Maybe you should do some reading.
 
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