Author Topic: To constrain Li-ion cells or not ?  (Read 3909 times)

john.emde

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To constrain Li-ion cells or not ?
« on: July 10, 2014, 07:09:32 PM »
Li-ion cells expand as their State Of Charge reaches or passes 100 %.
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A  cell may be damaged if this expansion is not contained (due to layer separation).
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Most of the info here comes from sources unknown and was compiled from my notes and experiences over the years.  Reader discretion is advised.
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« Last Edit: September 09, 2014, 11:30:41 AM by john.emde »

ted.lowe

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Re: To constrain Li-ion cells or not ?
« Reply #1 on: July 11, 2014, 01:41:25 AM »
Thanks John for sharing your EXCELLENT compilation!!!

ted.lowe

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Re: To constrain Li-ion cells or not ?
« Reply #2 on: July 20, 2014, 03:25:56 AM »
This looks like a source of some of John's compilation.  This is useful in understanding the 'constraining' or 'banding' or 'side clamping' issue in more detail.

http://liionbms.com/php/prismatic_tips.php

john.emde

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Re: To constrain Li-ion cells or not ?
« Reply #3 on: July 20, 2014, 03:03:36 PM »
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After working with Li-ion cells for some time now, I firmly believe that banding the cell stacks and using a BMS is the way to go. Protect your investment.
John
« Last Edit: September 09, 2014, 11:31:58 AM by john.emde »

ted.lowe

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Re: To constrain Li-ion cells or not ?
« Reply #4 on: July 21, 2014, 01:21:48 AM »
Thanks John!  i think i decided today to band my cells, because it can't be that complicated or expensive, and what would it hurt (if it wasn't needed).  Seems like a simple cheap practice to follow.

Do you know what tools / supplies are needed or someplace i can have the cells banded affordably?  Thanks!

i haven't decided yet about the BMS, but doing lots of research and thinking on the topic!!

john.emde

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Re: To constrain Li-ion cells or not ?
« Reply #5 on: August 10, 2014, 02:33:47 PM »
 
Quote
"Do you know what tools / supplies are needed
or someplace i can have the cells banded affordably?"

Come to think of it.  Yes!   The guys at Build EV have the
knowledge and equipment to do the job.

Build EV  (630) 740-8826


« Last Edit: September 09, 2014, 08:56:45 PM by john.emde »

john.emde

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Re: To constrain Li-ion cells or not ?
« Reply #6 on: November 08, 2014, 05:44:42 PM »
Included is a pic of part of the banding process.
The cells are stacked and aligned with plates at either end
and lightly pressed together to hold them in position.
Then usually 2 or more steel packing straps are tightened
around and crimped to hold it all together.





« Last Edit: November 08, 2014, 06:16:42 PM by john.emde »

ted.lowe

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Re: To constrain Li-ion cells or not ?
« Reply #7 on: November 08, 2014, 07:03:33 PM »
Nice John, thx!