New weldless battery system crowdfunfing project

Batteries, Chargers, and Battery Management Systems.
john61ct   10 kW

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Re: New weldless battery system crowdfunfing project

Post by john61ct » May 31 2019 9:29am

Yes obviously it **can** be done, just a question of time, effort and funds available.

Good such systems are inevitable as the market matures.


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liveforphysics   100 GW

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Re: New weldless battery system crowdfunfing project

Post by liveforphysics » May 31 2019 5:50pm

Polycarbonates + humidity + voltage stress = crazing (surface cracks), then crumbling.

Sometimes even good base plastic materials (polypropylene, Polyethylene can use a filler/dye that absorbs humidity and corrodes apart under voltage stress.

Test to validate whatever material you're going to use.
Each carcinogen vapor exposure includes a dice roll for cancer.

Each mutagen vapor exposure includes a dice roll for reproductive genetic defects in your children.

Each engine start sprays them into a shared atmosphere which includes beings not offered an opportunity to consent accepting these cancer experiences and defective genetics life experiences.

Every post is a free gift to the collective of minds composing the living bleeding edge of LEV development on our spaceship.

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Matador   10 kW

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Re: New weldless battery system crowdfunfing project

Post by Matador » Jun 03 2019 11:27pm

The springs I used a springsteel (tried the biggest spring gauge I could test). They litterally cooked at 4 amps per springs....
But springsteel has very high resistance... And will glow red hot and loose their recoil.

Berillium copper, well 38% IACS is certainly very impressive. I see hopes in this!
Does it spring back without deforming (even if it heats up ?).

You'd need something like that. Copper contact surface with knobbling would be good too:
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Reference for curious people: https://endless-sphere.com/forums/viewt ... 5#p1277444


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Matador   10 kW

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Re: New weldless battery system crowdfunfing project

Post by Matador » Jun 03 2019 11:35pm

And I mean knobbling on the surface like on this picture:
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agniusm   10 MW

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Re: New weldless battery system crowdfunfing project

Post by agniusm » Jun 06 2019 6:26am

flippy wrote:
Mar 06 2019 3:13pm
vruzend is a flawed concept with no regard for safety. that is simply the end of the story.

anything less then spotwelding is a compromise in safety and reliabliity.
I agree that vruzend is bad design and 2 majotlr flaws i outlined to them which they dismissed.
Saying that anything less than spotwelding is compromise in safety is a load of BS.
Spotwelding is least you can do. I have dismantled X2 batteries, the segway, and they are professiinally welded, glued but failed with corosion to spotwelds.
I have sold thousands of my solderless modules and in 2 years heard notging but good. In those 2 years i have seen many failed spotwelded packs.
Just saying, if some designs might look as disaster, others just might be better ;)

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flippy   100 kW

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Re: New weldless battery system crowdfunfing project

Post by flippy » Jun 06 2019 8:09am

your packs are not friction fit wich is a plus compared to vruzend, but is also suseptible to corrosion, even worse then welding.

and many people that fix or build batteries onyl see the busted ones, otherwise they would not go to a battery supplier.
Lithium beats liquid dinosaurs.

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agniusm   10 MW

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Re: New weldless battery system crowdfunfing project

Post by agniusm » Jun 06 2019 11:59am

flippy wrote:
Jun 06 2019 8:09am
your packs are not friction fit wich is a plus compared to vruzend, but is also suseptible to corrosion, even worse then welding.

and many people that fix or build batteries onyl see the busted ones, otherwise they would not go to a battery supplier.
Yes, not friction, compression. Regarding corrosion. I have left one module outside exposed to elements for a year including winter with temps of sub0 and snow. Only thing corroded was bolts i have left in it which were those high tensile, black ones.
I had nissan leaf pack which has tin plated copper bus bars from 2013 car and they looked brand new. Sure it probably was hermetically sealed but all electrical connections in power transformers, if not aluminium, tin plated copper. Also look at the tube ring lugs, same, tin plated copper, holding pretty good everywhere.
For the power packs i dont see spotwelding as an option. If you look at conductivity of nickel, it is 1/5 of copper. I have 0.6mm copper busses when most weld 0.15mm nickel. When you start layering nickel, it starts becoming a mess and reliability goes down. You are sceptical cause you have not tried it. Its too simple to go wrong :)

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BlueSwordM   100 mW

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Re: New weldless battery system crowdfunfing project

Post by BlueSwordM » Jun 13 2019 9:38pm

Wait, why would AG's design be prone to corrosion?

I mean, nickel-zinc/tin plated copper has excellent resistance to corrosion.
As he mentioned, only the steel bolts have been corroded, and that could be fixed with a zinc, then nickel, plating.

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agniusm   10 MW

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Re: New weldless battery system crowdfunfing project

Post by agniusm » Jun 14 2019 4:50am

BlueSwordM wrote:
Jun 13 2019 9:38pm
Wait, why would AG's design be prone to corrosion?

I mean, nickel-zinc/tin plated copper has excellent resistance to corrosion.
As he mentioned, only the steel bolts have been corroded, and that could be fixed with a zinc, then nickel, plating.
Thanks, exactly. Actually i address that with high quality stainless steel bolts from Japan and plastic screws and nuts from Germany. There is no issues regarding corrosion of what i sold and selling whatsoever. There is no current transferred trough fixings which would be bad idea so stainless works good

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BlueSwordM   100 mW

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Re: New weldless battery system crowdfunfing project

Post by BlueSwordM » Jun 14 2019 10:00am

Or if you are fancy, Titanium parts for the bolts and screws :)

Absolute overkill. :)

I'd like to add that I'm working on my 3rd Gen battery spring design.

Since I couldn't change the material to BeCu C17500 45% IACS because of its poor mechanical properties, or use the prototype material BeCu C17550 60% IACS as it would be wayyyy too expensive, I decided to look at multi layer electroplating. :D

I'll write more about it later.

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Ufobox   1 µW

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Re: New weldless battery system crowdfunfing project

Post by Ufobox » Jul 11 2019 11:24pm

Hi all, I'm working on my 18650 battery holder project, I red some relevant issues I face and trying to solve being discussed here. Below are some of the features I built into my battery holder :

- Cell Level Fuse (just positive ends). Negative ends are all connected.
- Stainless Steel Springs (just positive ends) apply cells contact pressure only, insulated, DO NOT function as conductor.
- Durable Materials, fiberglass and aluminium (functions as frame structure and bus bars).
- Easy to Open Battery Pack, for maintenance or inspection, bad cell/fuse/BMS replacement.
- Modular Design, one module is 12V (4S), scalable to 24V 36V 48V or higher.
- Easier To Build battery packs, eliminate the soldering/spot welding on cells contact.

Image
Image

I'm still waiting for some parts to complete the "module extension" (12V to 24V 36V 48V...so on), I try not to create "bottle neck" for current flow when scaling up the voltage of the modules. I hope the parts arrive soon and I'll show how to stack up the modules.

I have some short info on my blog which is still under development
https://leanmakes.wixsite.com/18650-battery-holder

Feel free to let me know if you see any flaw in the design at this stage. Thanks!
Last edited by Ufobox on Jul 15 2019 7:37am, edited 4 times in total.

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Re: New weldless battery system crowdfunfing project

Post by 1N4001 » Jul 12 2019 3:00am

Interesting. Are you using thread inserts as contacts? Those are made of brass, aren't they? You might want to consider making your own contacts out of copper, maybe even with one end closed for more contact surface. Brass has only 1/3 the conductivity of copper. For low-current situations that'll be enough, but for anything above 5A or so I'd definitely want copper contacts.

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Ufobox   1 µW

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Re: New weldless battery system crowdfunfing project

Post by Ufobox » Jul 12 2019 3:49am

Yes, in theory close-end nut will have more surface contact compare to hollow nut. But at the same time I found that there are many spot weld bumps on recycle 18650 even after cleaning/scraping.
Image

When placing a flat surface on the cell contact, the bumps create a gap in between result in less area of contact.
Image

When I place a hollow nut on the cell contact, there's no gap in between, maybe we have more contact in this case?
Image

Therefore I decided to use hollow thread inserts with the max diameter without touching the cell's negative.

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Matador   10 kW

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Re: New weldless battery system crowdfunfing project

Post by Matador » Jul 13 2019 7:19am

1N4001 wrote:
Jul 12 2019 3:00am
Interesting. Are you using thread inserts as contacts? Those are made of brass, aren't they? You might want to consider making your own contacts out of copper, maybe even with one end closed for more contact surface. Brass has only 1/3 the conductivity of copper. For low-current situations that'll be enough, but for anything above 5A or so I'd definitely want copper contacts.
Copper is quite soft and threads would easily strip. You're right, brass only has a third or so of the conductance of copper, but look at the wide surface area of contact... The bottle neck is not at the brass contact.

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Matador   10 kW

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Re: New weldless battery system crowdfunfing project

Post by Matador » Jul 13 2019 7:21am

Ufobox wrote:
Jul 11 2019 11:24pm
Hi all, I'm working on my 18650 battery holder project, I red some relevant issues I face and trying to solve being discussed here. Below are some of the features I built into my battery holder :

- Cell Level Fuse (just positive ends). Negative ends are all connected.
- Stainless Steel Springs (just positive ends) apply cells contact pressure only, insulated, DO NOT function as conductor.
- Durable Materials, fiberglass and aluminium (functions as frame structure and bus bars).
- Easy to Open Battery Pack, for maintenance or inspection, bad cell/fuse/BMS replacement.
- Modular Design, one module is 12V (4S), scalable to 24V 36V 48V or higher.
- Easier To Build battery packs, eliminate the soldering/spot welding on cells contact.

Image
Image

I'm still waiting for some parts to complete the "module extension" (12V to 24V 36V 48V...so on), I try not to create "bottle neck" for current flow when scaling up the voltage of the modules. I hope the parts arrive soon and I'll show how to stack up the modules.

I have some short info on my blog which is still under development
https://leanworkshop9.wixsite.com/18650-battery-holder

Feel free to let me know if you see any flaw in the design at this stage. Thanks!
Quite a nice project. The use of threaded inserts and nylon scews is brilliant

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Ufobox   1 µW

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Re: New weldless battery system crowdfunfing project

Post by Ufobox » Jul 13 2019 8:06am

Matador wrote:
Jul 13 2019 7:19am
1N4001 wrote:
Jul 12 2019 3:00am
Interesting. Are you using thread inserts as contacts? Those are made of brass, aren't they? You might want to consider making your own contacts out of copper, maybe even with one end closed for more contact surface. Brass has only 1/3 the conductivity of copper. For low-current situations that'll be enough, but for anything above 5A or so I'd definitely want copper contacts.
Copper is quite soft and threads would easily strip. You're right, brass only has a third or so of the conductance of copper, but look at the wide surface area of contact... The bottle neck is not at the brass contact.
Fuses are the bottle neck so I fuse the positives end only instead of both ends.

Copper nuts are costly compare to brass nuts. I try to make the best possible design and keep the cost low at the same time.

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Re: New weldless battery system crowdfunfing project

Post by 1N4001 » Jul 13 2019 8:23am

Matador wrote:
Jul 13 2019 7:19am
1N4001 wrote:
Jul 12 2019 3:00am
Interesting. Are you using thread inserts as contacts? Those are made of brass, aren't they? You might want to consider making your own contacts out of copper, maybe even with one end closed for more contact surface. Brass has only 1/3 the conductivity of copper. For low-current situations that'll be enough, but for anything above 5A or so I'd definitely want copper contacts.
Copper is quite soft and threads would easily strip. You're right, brass only has a third or so of the conductance of copper, but look at the wide surface area of contact... The bottle neck is not at the brass contact.
That depends on the alloy, you don't have to use pure copper.

Image

(and yeah, I realize that tensile strength isn't hardness)

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