Rev A and on to Rev B

Here are some pictures of the Mark II pack.

I have been having problems with one of my Mark I pack having leaking cells and I think it is due to uneven pressure on the cells.

I pulled the pack and you can see the electrolyte on the cooling fin

I am glad I made the pack easy to remove and replace cells.  This is the third time I have had to R+R bad pouches.

The MkII has very stiff end plates which I think mitigates this problem.  A couple of changes from the Rev - and Rev A design:  I glued plastic plates over the inside of the end plate to prevent possible shorts to the end plates from the tabs.  I also put a sheet of elastic foam between the end plates and the outer most cells.  This foam sheet acts as as spring to control the pressure on the cells due temperature, cycling, etc. and insultation on the threaded rod to prevent a electrical pat from the fins that may be touching the rods.

I am considering adding insulation in between the cells.  I haven't had a problem with it but others have:

http://www.diyelectriccar.com/forums/showthread.php/a123s-gone-bad-78971.html

The factory modules don't have any intracell insulation but obvious some people are having problems.  I have to do some more head sratching as to what the root cause of the problem is first.