Re-hydrating the battery modules.

My question is why would you have to re-hydrate a sealed module? I am reconditioning a pack. I have only worked on two modules. Many of the modules on one side that have not been charged or discharged have a small amount of liquid forming on the plastic below the terminal towards the bottom of the module. I rolled the pack over to get to the nuts on the underside of the pack. This may have put pressure on the terminals on one side. I do not know. Has anyone encountered this situation. If a drop of fluid comes out of a module, would that mean that module needs to be discarded? Example of problem - https://share.icloud.com/photos/08f8Pu0-07BDih5cV_vEH646Q The liquid looks blue but I think that is a reflection of a nearby object.

 

The bus bars had been removed so I don’t think it could have come from that. Do you have a feel for this as a problem? Have you ever heard of this before? I went and checked the pack a moment ago. I felt the terminal posts and they were wet. The weather here is wet and very humid. I would imagine the humidity is close to 100%. It has warmed up in the last several hours. If the battery pack is cooler than the surrounding air it is very possible that the liquid could be condensation.

 

That looks like purple/pink ink on the end of that flange, and it looks damp all the way to the end. The blue color in the "deeper" part could just be pigment migrating from that ink throughout the fluid, and it only looks blue in the part thick enough to reflect a significant amount of colored light.

Does the blue fluid occur in any area without that ink?

 

Group 6 seems lower than group 5 you rehydrated. I probably choose 6 instead..
Anyways... almost a year since you did this stuff.. Any issues so far? and by re-hydrating, are you referring only to injecting distilled water or the solution indicated at the beginning of this thread?
I had order already the "potassium Hydroxide" from Amazon, arriving next week, so I have 13 modules I can use for testing or trying to recover them. Most of them weight ~1032g and those I bought from ebay to replace them weight between 1036 to 1044g. The only strange situation I saw is that many of my batteries that still have very good capacity, they measure between 1032-1034g, similar to those with no capacity (~0.500 mAh)

 

My first attempt was witha solution of demineralized water and caustic soda I drove about 45 days.
The modules developed an even higher resistance ( up to 33 ohm) after a few days, I guess the demineralized water was the problem. Distilled water should have been used. Further I noticed increased bubbling and module inflation immediately after the injection, my understanding is that the factory hydrolite gel is made to minimize bubbling.
I have replaced the modules with newer ones ( not new)

 

Thanks for the reply! I am trying using distilled water and 10% of Potassium Hydroxide, but I am encountering same situation as Alex @a_triant. I am in the process of charging/discharging 2nd battery from those I replaced, hoping I can get good results on some of them..

I am getting entertained with the process. 4 modules I got them drilled to pop the valve. The first module I injected air with my battery portable compressor with automatic pressure set at 150PSI... around 100psi it exploded from one side.. well at least it could be tear down. to see more inside them.
For the rest of the modules I clamp them between woods to prevent the explosion, and then paused the compressor at 85psi, 90, and at 95 were after 2 seconds it started to inflate the balloon i placed on the vent valve. So the other 2 did the same and all of them; the valves opened at around 95-96psi and closed again at 80psi.
So the first one I started charging, could not accept so much charge with my tenergy T180 because its Vdelta setting was 5mv and it stopped charging with only 500mAh pushed in. So I continued the cycle like, discharging to 5.4v, and last to 3V... charged and discharged to obtain capacity but it did not changed from its original 700mAh. Same as with Alex, resting voltage was around 7.7v.
Then I changed deltaV setting to my charger to 25mv so it will not stop so early, and leaved it charging for 3 hours at 3A... Voltage rised to around 9.20v... I discharged it back to 6V... but it is still around 700mAh capacity. I checked with my thermal camera and the cell near to the negative post was slighly colder than the other 5, so I am concluding that cell is bad beyond repair. The other 5 cells were just struggling to dissipate with heat the current I was pushing, but that weak cell never responded.

 

These batteries will suck the life out of you.
The vent valve is junk, will over pressure, the negative post seal will fail and leak even when not charging.

I got fed up and put in the Nimh cylindrical cells from yabo I believe.
Been a year, the batteries remain within 0.05v, so far so good)

I made a 70(S) LFP pack from headway cells.
The folly is linked here:
HV Battery Headway 38120HP LiFePo4 70S pack | PriusChat
They were used, not matched and struggled with the regen current.
Went out of balance every 6 months and usually had a cell failure every couple months.
Does not fit cold weather applications.
Newer LFP tech may be more tolerant.

If anyone is interested there are lithium blades available:
Brand New 7.2v 6.5ah Auto Cell Lithium Ion Hybrid Car Batteries For Toyota Prius Gen 2 3 Camry Aqua Lexus Ct200h Cell - Buy Lithium Ion Batteries
prius Replacement Battery Lithium
prius Lithium Hybrid Battery Product on Alibaba.com
Just saw them this morning, don't know anything more about them.

 

Or you could just toss a lit flare into the cabin and achieve the same result a little faster and with less work and expense.

 

Did you pump air through the drilled holes? How was the tightness ensured?
During the charge-discharge process, water is converted into hydrogen and oxygen, and then back again. Excess gas escapes through a leak and moisture is lost again.

 

Same as John, did 1 drilled hole the size of the ball air injector needle..
For the charge/discharge procedure, used a hole per cell (6) to fill the 9ml solution (injected 10ml with a plastic needle syringe and retrieved it 1 or 2 mm to suck the excess, so on all of them the total solution remained was 9ml, similar to the patent), and leaved them open, when charged it bubbled when heated.

I am doing the experiment in 3 modules, one with just 0.3Ah capacity, the second one with 0.7 Ah capacity and I hope today will do it with a module that have around 1.4Ah capacity... So far, no increase of capacity on the 0.3Ah and 0.7Ah modules.

 

How adventurous !
Those looks interesting... how much it cost them and where? I googled yabo and I found them on Alibaba.com with a price of $82 plus shipping. But description is not that clear if the $82 is just for a 14v module or for the 14 modules needed for the prius. (I guess is just per module)

 

Why 9 ml? Overfilling is dangerous.
Heated water and its steam expand, and excess electrolyte vapor gets into all the cracks
Did you weigh the elements before adding the solution?
It is difficult to distribute this water evenly among the cells. There are very small drainage holes at the top between the compartments to allow the solution to move throughout the battery. Rather, it is for gas, to relieve excess pressure.

 

Thats the recommended quantity consensus here, around 9ml which is topping each cell and then remove the excess until the cell is just slightly covered. Each of the 6 cells have a drilled hole to fill them equally with the solution. As indicated, the charging/discharging procedure was performed with the holes on each cell still unplugged, so vapor can escape without causing any pressure.

 

Well, not so good results with 3 batteries, did all the procedures... but not a sucess. With the 3rd battery, highest capacity of them, the capacity when I discharged it until 5.4 v were around 2Ah, but on the final charge test It just discharged to 6v with 0.7Ah... Also, I found out that those batteries are not longer detectable by my T180 charger when reached full, so they are charged until the safety time I set on it.

 

Possibly a large overflow of water affects the readings.
The contact group inside the module must be above the electrolyte level.
Otherwise, rapid self-discharge of the cell may occur.

 

I'm looking forward to the test results of your fourth battery. I just want to share a little information that I hope will help you. I have done similar experiments before. I tried adding water to a battery that had lost capacity due to drying up of the electrolyte. I couldn't get sodium hydroxide. Among them, all failed in Toyota battery experiments. But it has been successful, and that is the second-generation Honda Civic battery. It is cylindrical, with a total of 20 batteries and 10 sets. I made a small hole on the side near the top and injected about 10ml of drinking water with a syringe. After that, the capacity increased a lot. It was just troublesome to seal the hole. I used a soldering iron to weld it. It should leak out soon。
But it didn't work on the third generation Honda batteries. I guess they may use different plate materials and the strength of the plates is different. For batteries with collapsed plates, adding electrolyte will not work. With the same idea, I speculate that the third-generation Prius battery is easily damaged, and this may be the reason.

 

A trusted battery expert from here, @2k1Toaster, imports quality cells and warrants them at newpriusbatteries.com