HV battery corrosion

Interesting. The Classic Prius traction battery pack tends to show much worse corrosion as the battery module sealing is not very good.

Is the corrosion widespread on the busbar hardware, or does it appear only on the two modules that you photographed?

My guess is that if you remove the busbar and look behind the modules that produced the corrosion, you will see some electrolyte leaking out from the terminal.

Regarding the terminals that are corroded, does the corrosion appear solely on one polarity terminal (i.e., the positive side or the negative side only)?

 

The battery has two busbars, one on either side of the battery. These are the orange plastic assemblies with copper conductors that are partially shown in your photos.

Assuming that you plan to put the battery in service, I suggest that you remove the busbars, clean off the corrosion the best you can, then reassemble.

 

You might discuss the situation with Bob Wilson (posts here) because he has done major work in refilling and sealing NiMH cells.

 

Seems reasonable to use fine sandpaper to clean the copper.

What is the black ring around each of the battery terminals - is that sealant or is that leaking electrolyte?

Are the serial numbers of the battery modules consecutive, or do they jump around? I am wondering whether someone swapped modules in and out of the battery pack before you bought it.

BTW in case you do not have a repair manual, note that the tightening torque of the nuts that hold the busbars to the module terminals is 48 in.-lb, 5.4 Nm, or 55 kgf-cm.

 

this happened to my 01 prius, sunday its going in for a replacement HV battery due to severe corossion ( free of charge)

 

The 'black stuff' around the terminal is the rubber O-ring. Under stress, the batteries develop significant internal pressure and over time, it appears to seep out around the terminal, primarily the positive terminal.

The electrolyte is KOH. If you have a PH kit, you should be able to take a swab of the area and detect a high level, 12+.

Sorry but I'm fighting off a cold this weekend and other maladies. I'll go back to sleep now:

http://hiwaay.net/~bzwilson/prius/pri_batt.html

Bob Wilson

 

Some aquarium/pet shops may sell pH paper?

The recommended way to neutralize KOH is with boric acid (pharmacy), but baking soda (NaHCO3) would work reasonably well as a ocnvenient alternative.

Hot tea, honey and lemon, Bob.

 

Good idea about using Coca Cola. I guess my digestive system should not have any copper oxidation within, given that fluid's cleaning power which you demonstrated...

KOH is potassium hydroxide.

What is the model year and odometer reading of the car that your salvage battery came from?

 

I understand there is a shortage of Classic traction batteries; 4 - 8 week delay to receive a new battery. Has your replacement battery arrived at the dealer?

 

I recently purchased and installed a newer / lower mile HV Battery in my 2006 Prius which gave me an opportunity to dissect the original battery.

I was surprised to see all the corrosion on the bus bar terminals. I'm thinking the corrosion build up on the battery is partly due to the AC drain line clog I had on my car last year. That issue lead to a temporary build up of moisture in the car which most likely resulted in the corrosion seen in the following pics.







My plan is to drop the nuts and bus bar plates into a cup filled with CLR over night then use a dremel tool to finish the job. I'll clean off the battery terminals with a soft wire brush.

If I apply petroleum jelly to the finished products, will that hurt the conductivity of the parts in question?

Thanks,

Mylar