tabless A123 ?

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HeadsUp
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tabless A123 ?

Post by HeadsUp » Fri, 02 Dec 2011, 13:43

EClubman wrote: Can I suggest that these staples are great quick and dirty way to connect tabbed cells for testing on the workbench, but definitely NOT what you want in a pack for an electric vehicle.

These jobbies were designed to hold a wad of paper together in an office environment, not conduct up to 600A of current in a dirty, vibrating EV pack.

Conductivity, corrosion, area of contact patch, what happens if one should come loose inside the battery box.

I think that something like a braided cell interconnect folded over the two connecting tabs and then a bolt through the middle to hold it all toegether would be much more robust. (Though then you have the issue of how fat this connection is compared to the width of the cells to deal with)

Mark


not proposing that the clip conducts power , clip only holds the contact faces together.

there are medium and heavy duty versions of these clips , and while i will point out i have not tested any yet on the bench , if they are found to be too light then there is opportunity to have a few thousand heavier ones pressed up in your pick of the 500 sheet metal companies around the country who could do so

manufacture and cad plating might cost 8 - 20 cents per clip

there are many photos on the web of machined blocks used to clamp them together . they are too bulky and expensive IMHO , probably costing $ 6 - 15 per each.

i would not be drilling holes through the tab

my proposal was to use two clips per tab , have a copper bus bar plate at least 1mm thick under the clip on each side where the tabs are mated , and where a connector is fastened to a tab you would use a mini bus bar of around 1.2 - 1.6 mm thick ,and use conductive grease or bonding agent between each tab and bus bar joint

have you looked at the thickness of the tab material ?

whats the point in having an 8 mm conductor bolted to a 0.4 mm thick tab ? ( i am guessing btw - i didnt measure one yet )

there will be a more elegant solution to this.

cheers


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Johny
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tabless A123 ?

Post by Johny » Fri, 02 Dec 2011, 14:12

EClubman wrote:These jobbies were designed to hold a wad of paper together in an office environment, not conduct up to 600A of current in a dirty, vibrating EV pack.
Mark
I agree with Mark. I'm using them for upholstery clips (seats) in the Vogue. They are stainless steel but they are not that strong and don't have much contact area for thin material. They are called NalClip.

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Johny
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tabless A123 ?

Post by Johny » Fri, 02 Dec 2011, 15:32

HeadsUp wrote:not proposing that the clip conducts power , clip only holds the contact faces together.
I really have found that even after first application they (NalClip) don't have the clamping force that they had before applying. The applicator spreads them a lot. They also are not as "springy" as real spring steel. Maybe something to do with being stainless. For my purpose they are perfect as I'm clamping fabric around a 5mm wire frame (seat) but not for thin material - even the small ones aren't that strong.

You are also comparing a nut/bolt clamping force with that of a thumb and forefinger - massively different. The system we saw in the ebay add wasn't that bad. A lug either side, not and bolt , then support the cables mechanically so they don't stress the cells. Don't drill the holes, punch them. That technique means you have more freedom in the mounting positions of the cells too.

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Adverse Effects
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tabless A123 ?

Post by Adverse Effects » Sat, 03 Dec 2011, 03:43

this would be a simple tab clamp to mass produce with the right extrusion die for Aluminum

there may even be something out there that is close to it

Image
Last edited by Adverse Effects on Fri, 02 Dec 2011, 16:45, edited 1 time in total.

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Adverse Effects
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tabless A123 ?

Post by Adverse Effects » Sat, 03 Dec 2011, 04:35

or an even simpler one to make

Image

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Richo
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tabless A123 ?

Post by Richo » Wed, 14 Dec 2011, 21:14

Aren't you ment to just solder to them?!?
So the short answer is NO but the long answer is YES.
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