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

 

Being a Chemist in a former life, at least seems, I would consider the black is Copper (II) Oxide. The other colors might be due to the nickel and or electrolyte potassium hydroxide present as well. So Copper (II) Hydroxide as well. Not sure if the carbon dioxide, sulfur or nitrogen from the air present possibly as well under certain conditions forms a product like maybe from arcing like a higher energy situation like how nitric acid can be produced so like a Copper (II) Nitrate is produced. I doubt heat in the humid overheating or higher resistance situation would cause alone, though maybe there is some sort of surface plasmonic situation? Rust and corrosion are basically a result of a chemical reaction known as an Oxidation Reduction or RedOx reaction. So literally the copper when exposed to moisture, heat and air will form it's own form of rust like Iron does to form Iron Oxide and in regards to copper, forms Copper (II) Oxide instead.

You can think about the Nickel above in the same way as copper and consider the products from the RedOx reactions as well.

Electrochemistry is another more detailed study of these situations where kind of like if you've ever seen the electrolysis of water using platinum electrodes, that don't react with the oxygen or hydrogen or electrolytes or ions in the water, to form oxygen and hydrogen.

Instead, if copper was used on the positive electrode (cathode), hydrogen would be produced and if copper was used on the negative electrode (anode) under certain conditions the loss of electrons occurs causing oxidation more likely and causing the change color due to the salts formed like say an oxide or like whatever ions and electrolyte was present. Read into electrolysis thermodynamics more say like on this wiki.

I won't even go into the charging versus discharging situations for the rechargeable nature of the battery and all surfaces involved. Get's more confusing and requires me to have to think out all the systems situations more critically. Might be the oxidation forms more due to the capabilities of the battery and not only environmental conditions.

Please correct me if I made any mistakes in my writing and thinking. I have had many head trauma experiences in the course of my life.

 

Thank you for that, a very thorough explanation. I'm not going to challenge what you know, your knowledge is well above my pay grade as they call it ...... I know that oxygen reacts with the electrolyte (KOH) to form a carbon-ate or ite, can't remember which, so maybe the arcing through moisture causes electrolysis and provides a rich oxygen and hydrogen environment that also creates, no idea what the gases released would be from KOH would be, but I can't imagine it would be good from the long life of the copper surface ...... Just conjecture at this level, no equipment or knowledge to interoperate any results I found, even if I had the equipment

T1 Terry

 

I was actually wondering about the Copper (II) Carbonate Hydroxide. Great call!

 

I'd settle for lucky guess, but thank you all the same

T1 Terry

 

Figured I'd note regarding the surface plasmonic effect I was thinking being somewhat like I envision as a Kirlian photography like situation where the DC-DC converter charging maybe doesn't have a photonic visible light range or purely light causing the effect. I was considering more a radiofrequency (RF) range from I guess 50 to 500kHz at the HV 200+DC Volts of the system with microscopic breakdown voltages possibly emitting plasma whether visible or not. Might not be visible to the naked eye, though maybe be that effect miniscule. Man, this stuff is neat if I had the time to research more. Molecular energy levels and relationships for optimal reactions effects based on those molecular energy modes, like simply thinking translational, rotational, and vibrational modes maybe be somehow related to effect.

Another thought is the corrosion reminds me of electroplating as well and the dendrite formation within the cells to make them go bad, albeit completely different reactions. OK, time for coffee and back out of dreamland.

 

A combination of the complete circuit voltage and high current moving both direction, it is amazing that they hold up as long as they do. Looked at the faces of different types of busbars under high magnification, when I was first deciding which system to use for our house battery builds, the evidence of arc pitting and fretting when solid copper busbars were used, worse as a dry contact, but still evident with the use of alminox, compared to the 0.5mm thick milti layer stack, determined by the expected current transfer with a 50% safety margin and a "hump" in the middle to allow for movement, Alminox between each layer, showed no sign of arcing after 24/7 used over 3.5 yrs, so we determined, that was the standard we'd use and could have possibly gone longer between servicing, but the cells were showing clear signs of memory affect .... but that one is hotly contested in the LFP community as to whether it exists or not, so I won't expand on that topic Let's just say, those in the MG community with the smaller capacity LFP batteries, are showing an improvement in battery health if the cell are cycled deeply compared to shallow cycling ...... Maybe what I was reporting back in 2011 wasn't a silly as the world of experts believed ..... The fact that LFP cells do not have a shelf life or cycle life of 10 yrs has been well and truly debunked as well, I have systems I built back in 2011, still functioning 24/7 365 days a yr, still testing at better than 100% advertised capacity using the manufacturers 0.5CA (2C) test rate

T1 Terry