Using Noalox? (Hybrid Battery Reconditioning)

I just used a q-tip shined on coating of DeOxit L260D grease again. Only enough to polish the mating surfaces and not enough, so to remove my paranoia of melting traces of conductive grease that flow into a P0AA6 DTC. Figure is conductive and will see in the long run what the difference is. Feels like dialectical grease in this situation as well.

 

It is advertised as increasing conductance by removing corrosion. They also say that it does not itself conduct. I find it to be a peculiar product since its properties work in both directions with respect to conductance. I wouldn't use it. I have a suspicion that the DeOxit grease "works" by being extruded from the contact zone so that the microscopic rough texture of the metal can make electrical contacts. Clean off the metal with something that can be fully removed and then screw everything together and then maybe problems from a slightly too thick layer of grease here or there will never arise.

 

The cause must first be sorted, before anything will work to stop the corrosion and the wicking up the wires and damaging the BMS (battery computer in Prius terms). The pressure release valves in the modules get themselves glued in place and won't release the built up pressure at the required 80psi. This causes the seals around the terminals to leak .... it might have been smarter to put the terminals on top, so they weren't in the liquid, but once the liquid comes into contact with oxygen and copper, the corrosion occurs.

I've tried Alminox, which is a similar product, and once the pressure problem is sorted, they corrosion stops being an issue ...... I've also experimented with electrolytic nickel coating with some success, but again, only after the pressure problem is sorted.

T1 Terry

 

Not sure how to get the image to appear, but it can be seen the negative end terminal is affected more than the positive end (think I have that the right way around, forgive me if I've got it back to front, I'm no where near my NiMh sample modules at the moment) Has anyone tried wiring the voltage sensing wire tab to the other terminal to see if that improves the BMS faults occuring?

T1 Terry

EDIT: If you enlarge the photo of the busbar with the corrosion on it, look at the end with the most corrosion and smallest copper patch exposed .... does that look like arc pitting to you?

 

That's my question. Why do the copper busbars turn black on the negative side? I tried to find a scientific explanation, but I couldn't find it. I had a theory that this was due to a decreased capacity, but I took apart an old battery, which I repaired for about a year and 11 months before it failed again and the busbars were not black either on the positive or the negative side, and the capacity of the modules was ~2000 mA. Blackening also occurs on new busbars from Toyota. I once replaced busbars with new ones from Toyota, as the original one was broken and it also turned black on the negative side when I disassembled it after 7 months. The blackening begins immediately after use on new busbars too, but why?

2005 prius 171k miles. Failed original battery driven in Washington DC area. (2024)


2007 camry 84k miles. Never used on car. Charged with prolong charger twice. (2023)


2007 prius 67k miles (2023)


2012 Primearth replacement battery from Toyota (2023)


2015 prius c 30k miles (2024)


failed old battery with new busbars from Toyota


self made busbars after 2 years ~50k miles


Tumbler machined cleaned busbars

 

I'm going with electron flow between two dissimilar metals with a bit of electrolyte vapour or mist thrown in through leaking seals.

We had similar reactions using copper busbars on aluminium cell terminals when high current (200 amps or more) flowed from cell to cell in our LFP house battery systems. Cleaning the copper busbars till they were shiny using Scotch Brite type buffing discs (blue grade) as well as the terminal faces and every face painted with a good coating of Alminox, stretched the need to reclean the faces and terminals to 3 yrs on a full time system(24/7 365 days a yr, 5 to 8 yrs yrs on a not quite so hard worked system.

The giveaway that the busbars needed cleaning was a variation of voltage between series cell voltages exceeding 300mv between charging and discharging cell voltages ..... keep in mind, these are 3.2v nom. cells, so reading 3.6v charging then 3.3v discharging even 5 amps from a 400Ah battery pack, is a serious swing, normally the swing is less than 5mv when the busbars are making a clean contact. Tight clamping force is also essential, if those captured washers on the nuts are flat when removed rather than cone shaped like they are new, they are not applying enough even clamping pressure .....

T1 Terry

T1 Terry