SSN Fix: DIY Upper HV Pack Heat Exchanger (Cooling Plate) Removal

[Anti_Climax]

Depends on the temp. At 120-something it forces a stop. Below that is a range where it's degraded performance and below that a range where there's no error but it's totally bypassing the cabin evaporator.

 

[27ace27]

Interesting. I wonder if we have different BECM firmware or something. Mine never forced a complete stop, it just kept limiting performance until the car barely moved.

 

[Anti_Climax]

How hot did it get though? Was it a yellow warning or a red warning?

 

[27ace27]

Yellow, then red.

 

[Anti_Climax]

Had to unplug my charger and the car sat in the PHX sun all day. Can confirm, hybrid battery temp of 122 gave a "stop now" message.

Changed to "severely limited performance" with a red turtle at 121-120F. When it switched the battery indicator (which was up above 99%) showed 0 miles range and began counting up to 95+ miles.

At 118-117F the turtle went yellow and just "limited performance"

At 114-113F the warnings went away but AC was still fully redirected to the battery loop.

At 112-111F, the AC began working in the cabin.

 

[27ace27]

Good to know!

 

[27ace27]

Quick addendum here:
Ford addressed this issue in the 33.5 kWh packs by adding clamps to keep the cell stacks compressed. At first glance, this seems like something that it would to be easy to retrofit the 23 kWh packs with. However while there is plenty of research on compressing new pouch cells, I could not find any on compressing aged pouch cells.

My concern is that the pressure would crush the hollow heat exchanger plates and we'd be right back at square 1. The ideal solution would be to vent the accumulated gas somehow. While doing so safely is relatively straightforward, there doesn't seem to be a reliable way to re-seal the cells afterward, as the electrolyte contains a solvent which would degrade any adhesive patch. Since the electrolyte and the gasses that cause the cells to swell are both highly flammable, this makes such a solution a complete non-starter.

Unless I can find a way of reliably re-sealing the cells, I'll probably just try the clamp retrofit without venting the cells first. Maybe with a quick shutoff valve installed in the coolant loop

 

[27ace27]

Have found a further downside to this mod: at high-ish ambient temps (was seeing this at 90-100F), charging throttles hard.

This seems to be due to the onboard charger (SOBDM) overheating. As best I can tell, whether the car activates the chiller in the battery coolant loop is based solely on the temperature of the coolant going into the battery. When battery cooling is bypassed, this always reads ambient. So as long as ambient temps are below chiller activation temps, the SOBDM relies on ambient cooling.

I'm not even sure whether the coolant runs through the radiator yet. I'm thinking probably not though; the temperature of the coolant going into the SOBDM was ~124F when ambient was ~90.

 

[Anti_Climax]

You could potentially set up a temp sensor in the coolant stream and make it think it's in the upper pack.

And for sealing cells after degassing - perhaps something that isn't an adhesive in the traditional sense like epoxy?

 

[bbsprint]

In follow up to my previous post (where I removed the upper HV battery pack), I'll post this so you can at least have an idea on how to disassemble the battery pack. Make sure you have some insulated tools or if you can't afford those, just wrap them in electrical tape. It has been some time since I have worked on the battery, so most of what I'm posting is off my memory. Please be aware you are dealing with high voltage around 360 Volts, and this can potentially kill you. *** Have a phone or camera handy and remember to take plenty of pictures, as there is a lot of wires/ connectors that MUST go in their designated spots!*** Once again, Thanks to Tareq Awad and Sebastian Zuzga on the FFE facebook group for the guidance and help with this!

Awesome post skyguy thank you for all your effort. I have an upper pack leak which I have out of the car now and was just wondering your thoughts on weather or not after draining the pack I could just put it back and add in a bypass loop to it? Or do I have to remove the cooling plates? Also the lower pack does not have a leak so would you recommend a bypass loop on it before it goes bad? Thank you in advance. bb

 

[27ace27]

Bypassing the lower pack is recommended, yes. It will eventually leak as well. As for the upper pack, draining it alone is not likely to fix the SSN message. If you do end up removing the cooling plates, please let me know. I would like to purchase a few dozen.

 

[bbsprint]

Bypassing the lower pack is recommended, yes. It will eventually leak as well. As for the upper pack, draining it alone is not likely to fix the SSN message. If you do end up removing the cooling plates, please let me know. I would like to purchase a few dozen.

So I did end up removing the cooling plates from the upper pack and I have a whole box of them.

 

[27ace27]

So I did end up removing the cooling plates from the upper pack and I have a whole box of them.

Just sent you a PM

 

[ajbessinger]

I run an EV repair shop in Portland OR, and just picked up a FREE 2013 FFE yesterday in a non running state. I was able to get the car driving again by clearing the codes with ForScan, but it did throw the dreaded P0AA6 code on one of my test drives, and after pulling the plugs, it definitely has coolant intrusion into the lower pack (upper pack is currently dry).

This will probably be a back-burner project for me as my main focus is working on customer vehicles, but I'll probably try to get the lower pack out sometime this week and work on pulling it apart. Ideally, after cleaning everything out, I'd like to see if it's possible to re-install the cooling plates and add some compression straps to the modules to keep the plates from separating, but I don't have my hopes up on that necessarily being a viable solution (compressing bloated cells is not always a great idea).

In any case, I'll be following along here to see if anyone is able to do that successfully, and will probably document my repair as well in video form.

 

[ajbessinger]

Just wanted to give a little update on my FFE battery repair project so far. I've got the lower battery all torn down, just need to start cleaning everything up for re-assembly, which hopefully won't be too much of a challenge (the cells are pretty swollen).

Assuming I can get the modules to fit back in, I think I've got a viable plan to put it back together while retaining the pack cooling. The idea is to mount the cooling manifolds "remotely", with flexible tubes going to each of the cooling plates. I'll take some more pictures when I get to that point (and will also be filming to put together some videos for YouTube).

 

[Heima]

Thank You Sir!

 

[bbsprint]

Hi ajbessinger, I’m looking forward to see how you’re going to mount the cooling manifolds remotely. 27ace27 mentioned how Ford addressed this issue in the 33.5 kWh packs by adding clamps to keep the cell stacks compressed. Are you planning on adding some sort of clamping system?

 

[ajbessinger]

Hi ajbessinger, I’m looking forward to see how you’re going to mount the cooling manifolds remotely. 27ace27 mentioned how Ford addressed this issue in the 33.5 kWh packs by adding clamps to keep the cell stacks compressed. Are you planning on adding some sort of clamping system?

At thing point, with the cells already swollen, I don't want to over-compress the cells and risk causing damage, so I'm only going to compress them just enough to fit back into position.
I've 3D printed a bunch of clips which will be attached to the modules with some 3M VHB. The manifolds will snap into the clips, and then I'll run individual silicone tubes from the manifolds to each inlet/outlet on the cooling plates.

 

[ajbessinger]

Got my battery pack re-assembled (getting the modules to fit back in was VERY difficult). I'll be working on implementing my modified cooling system today and doing some testing to make sure there are no leaks before it gets put the rest of the way put back together and re-installed in the car.

 

[ajbessinger]

My system to use the individual tubes to connect to the cooling plates ended up not working... The combined force of all the tubes bent at such a tight radius caused them to "push" the manifold out of position. Any tubing that was more flexible simply kinked when trying to bend at such a tight radius, and unfortunately there simply wasn't enough space to fit them anywhere else...

In the end, I ended up deleting to cooling system and bypassed it in the tunnel before the point where it tees off to the two packs. This also enabled me to evacuate as much coolant as possible from the upper pack, so hopefully I won't have to pull that one out anytime soon. I've put close to 100mi on the car (including about 40mi on a day where it was 90+ deg out) without any issues.

In the longer term, I might try to look into some sort of cell replacement option to retrofit into the pack, however that will be easier said than done since these packs are such a "strange" number of cells in series, and isn't divisible into equal sized modules because of that.