Corrosion on 0.1mm copper sheet?

[DefconExile]

I’ve just removed the fish paper insulation from my pack to make a horrible discovery…

My copper sheet has corroded quite significantly and I’m unsure of the cause. I understand copper oxidises but I’ve had some scraps off copper on my desk from when I cut out my plates 2 weeks ago and they’re still shiny

I wore latex gloves while handling the copper as to not transfer any oil from my skin thus speeding up the oxidation process , I also quickly taped up the terminals with kapton tape after spot welding , but they still appear to be tarnished.

I imagine corrosion causes resistance and is creating domino effect with my voltage meter this could explain a the issue in my pack right now

Here’s some photos for reference, any thoughts?

I personally feel unsafe charging this pack further while it’s in this condition I’ll have to remove this all and start from scratch but what can I do to prevent this happening again


Sent from my iPhone using Tapatalk

 

[Chalo]

Did your pack get wet? Maybe from condensation?

Naked copper in contact with other metals that have different election affinities can set up a galvanic reaction if there's any moisture present, and that results in more pronounced corrosion than simple exposure. Also having a voltage potential (which is what a battery is for) tends to promote corrosion.

 

[DefconExile]

Did your pack get wet? Maybe from condensation?

Naked copper in contact with other metals that have different election affinities can set up a galvanic reaction if there's any moisture present, and that results in more pronounced corrosion than simple exposure. Also having a voltage potential (which is what a battery is for) tends to promote corrosion.

It didn’t get wet but I’ve rid it in cold weather maybe the pack got warm and was cold in the outside and caused condensation under the tape

Or possibly I’ve drawn to the fact that the glue I used releases acetic fumes as I’ve used a silicone RTV and I believe vinegar also promotes corrosion I left it to cure for 48 hours though it recommended 24 too fully cure. Possibly taping it up with kapton has trapped in some of the fumes and caused corrosion , and further influenced by the use of the pack @ 45 amps


Sent from my iPhone using Tapatalk

 

[Chalo]

Yeah, for sure acetic acid reacts with copper to produce copper acetate, which is green. That's most likely your problem, but may not be a big deal if the acetic acid is fully dissipated. No more acetic acid means no further formation of copper acetate.

The silicone sealant used for electronics is called "neutral cure" silicone. If you're going to gack up your pack like that, you want to use neutral cure.

 

[DefconExile]

Yeah, for sure acetic acid reacts with copper to produce copper acetate, which is green. That's most likely your problem, but may not be a big deal if the acetic acid is fully dissipated. No more acetic acid means no further formation of copper acetate.

The silicone sealant used for electronics is called "neutral cure" silicone. If you're going to gack up your pack like that, you want to use neutral cure.

I just googled what you said (copper acetate) and it’s definitely this , colour is identical.

In future I’ll opt for something that states non corrosive or neutral cure as mentioned but for now I’ll just remove all the copper plating and cut out some fresh pieces, also leaving it for 7-14 days to ensure it’s completely cured with no more smell in hopes this problem doesn’t arise again

Thanks for the info


Sent from my iPhone using Tapatalk