Sony NP11 Battery pack rebuild

[mikemag]

I recently acquired a Sony BMC-220k betamovie with 2 battery packs that last about 1 minute
I am thinking of rebuilding the battery packs but haven't found any guides to doing a quality job for a vintage collectable pack, I don't want to treat this like a few year old tool battery pack where appearance is not a concern

does anyone have any advice regarding cleanly opening the NP11 so it can be put back together and not look bad ?

any other info would also be appreciated on this project.

I have seen some companies would do this for me but the cost makes that impossible for me, I don't want to spend $100 on 2 battery packs