Considering giving up the fight

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Thank you so very much for these photos!
It is very interesting, that at the top of the pack, the liquid appears to be water condensate, yet at the bottom of the pack it is definitely coolant. And the way the silver nuts are corroded, it appears that the condensate has been there for a while. I see that there is a break in a plastic frame at the silver nuts and it almost appears that the brackets for last three cells are "bent up". The white pipes do not look like they have a reliable method of fastening. That one in the center actually looks loose.
It will be interesting to know what else you find.
Thank you again!
 
Got a little further in teardown. No definitive leak points, but there is very definite swelling in some of the packs. That would seem like a logical cause. There was a lot of pressure built up. Will post some pictures in the morning.
 
Here are the pictures from last night. From seeing where the coolant sits, seems like the swelling is a likely culprit here. My concern is if its safe to reassemble when there are clearly some bad cells here. Is that a fire hazard? Im far from a battery expert. I do have to say Im a bit surprised by the "less than robust" way they have the cooling lines set up. Seems like ok for a low pressure water system for a stationary system, not a car that shuffles and vibrates constantly.







 
In a perfect world, I'd say you'd want to swap out those cells. But with the monitoring in place I would expect the car to complain before fire is a real risk.

If nothing else, you might be able to get some cell assemblies from another pack to replace the suspect ones. If I'm seeing things right, that may also address the leaks themselves, yeah?
 
More disassembly and some better news. Following the guide linked earlier, I'm actually removing all the cooling plates and with that, the packd come back together fine. More pictures later. Lots if leaked coolant in the bottom.
 
New pics...
I now have all the cooling plates out, and am in process of wiping down all the stuff. So much coolant...I'm surprised it ran at all. I would estimate a good half inch deep at the bottom of the lower pack, so battery packs just swimming. Will start re-assembly soon.

















 
Has this coolant leak been observed with the lower pack, or does it always happen with the upper pack? If the latter, does anyone have any insight into why that might be? I have a 2017 approaching 40K, and it's our primary daily driver. It's especially important that the car stay reliable right now with gas prices being as high as they are. I'm getting nervous about keeping the car for a long duration. I would drive it until the wheels fall off, but this swelling cell and pack leak issue seems to arise repeatedly.
 
So maybe this is something that we could put our collective heads together and try to figure out. Why are the cells swelling?

I found this article online: https://www.dfrsolutions.com/blog/why-do-lithium-ion-batteries-swell
and there are 5 reasons listed:
  • Overcharge conditions which accelerate parasitic reactions between the electrodes and electrolyte, with release of heat and gases.
  • Poor cell quality and design with low anode to cathode stoichiometric ratios, particulate contamination
  • Mechanical damage to electrodes induced either during cell assembly or from the product application
  • Excessive temperatures (Do not leave your cell phone inside your car)
  • Deep discharge of cells

My thinking is:
Overcharge, this seems extremely unlikely, as there is a fair amount of technology going into the charging systems. Unless when the inverter is regenerative braking, its sending a too high of a voltage back into the battery.

Poor cell quality, unlikely, but possible. As formulations and processes improve, the quality will only get better. But was it that bad in 2012, and has the methodology of making the cells not improved with each model year? Or were there battery packs made from cells manufactured the year, two years, or three years before?

Mechanical damage, seems extremely unlikely, as the batteries appear to be fairly well constructed and well protected by the enclosures.

Excessive temperatures, unlikely with the thermal management system, but possible. If the vehicle were parked in the heat of Phoenix for weeks on end, I could see the thermal mass of the battery eventually raising to almost daytime air temperatures. But is that enough to promote swelling?

Deep discharge, this might be it, but how deep a discharge, for how long promotes swelling? We know dealers know nothing of electric cars and will let them sit on the lot and discharge till dead. Most EV have a minimal voltage cut out, but the self-discharge behavior of the battery can still kill it.

Maybe it is the combination of poor cell quality, excessive temperatures, coupled with deep discharge.

Anybody else have other ideas/reasons?
 
Been some time, car went back together. And its still dead. I'm down to the main DTC Error Code: P0A0A; Definition: High Voltage System Interlock Circuit. Somewhere something isnt making a full circuit in what appears to be some 16 segment or so interlock system. I'm giving up. It makes me very sad, but the car is pretty much dead and useless to me now. Truly disappointed in Ford and in this battery design in general after seeing disassembled. I haven't seen other posts about the lower pack. But if its constructed of the same cells, it seems to me that its not going to last.

Anyway...if anyone wants a project or needs spare parts on a 50K mile car, please let me know. I have no clue how to even sell this thing for more than scrap. Just sucks.
 
I am sorry that you have an HVIL problem, but it isn't as complicated as you might think. Each high voltage connector has a mini subconnector for HVIL. The error that you got means that some high voltage connector is not properly seated/fastened. From the service manual:

P0A0A:01

Normal Operation and Fault Conditions

The PCM monitors the DC to DC Converter Control Module (DC/DC), PTC heater, the A/C compressor module and the TCM high voltage circuits. The high voltage interlock system verifies these connectors are properly connected. The PCM sends a 5-volt reference signal to each connector, in series and monitors the voltage return. The PCM high voltage interlock sense input checks for continuity of the high-voltage system interlock circuit. The interlock circuit must have continuity before high-voltage is supplied to the vehicle. The interlock circuit voltage travels through each of the high-voltage components and high-voltage cables and back to the PCM . The PCM sets a DTC if voltage on these inputs are above or below a calibrated threshold.

Possible Sources

Connectors damaged or pushed-out terminals, corrosion, loose wires and missing or damaged seals
High voltage components
High voltage connector C1822B shorting bars installed properly
PCM


DTC Fault Trigger Conditions


DTC Description Fault Trigger Conditions
P0A0A:01 High Voltage System Interlock Circuit General Electrical Failure The PCM detects greater than 4.9 volts or less than 0.1 volt at the high voltage interlock sense input.


I believe there are two HVIL loops, and it is possible to "fool" the system by bridging the endpoints of the loop. This defeats the safety of the interlock, but it should get you going again if you cannot find the suspect connector.

So it appears that if you were to bridge terminals 55 and 59 of connector C175B, you could override this loop.
C175b


55 ZA113 OG-GY 20 HIGH VOLTAGE INSERTION LINE SOURCE 1
59 ZA114 OG-WH 20 HIGH VOLTAGE INSERTION LINE SENSE 1
I guess 55 is Orange-Grey, and59 is Orange-White
The PCM is located in front of the front left wheel (drivers side) behind the wheel arch liner.


Alternatively, and probably easier, you could jumper across pins 13 and 14 of C1822A.


Again, they are the Orange-Grey and Orange-White wires of this connector at the top rear of the drive unit


That looks pretty dooable with two straight pins and a jumper wire.

Good Luck!
 
Heima said:
So maybe this is something that we could put our collective heads together and try to figure out. Why are the cells swelling?

I found this article online: https://www.dfrsolutions.com/blog/why-do-lithium-ion-batteries-swell
and there are 5 reasons listed:
  • Overcharge conditions which accelerate parasitic reactions between the electrodes and electrolyte, with release of heat and gases.
  • Poor cell quality and design with low anode to cathode stoichiometric ratios, particulate contamination
  • Mechanical damage to electrodes induced either during cell assembly or from the product application
  • Excessive temperatures (Do not leave your cell phone inside your car)
  • Deep discharge of cells

Anybody else have other ideas/reasons?

The other thing that can hurt lithium batteries is drawing more current than they are designed to. I suppose this is possible but I doubt ford engineers would design the FFE to allow it to draw more current than the batteries can safely handle. I would think they would be very conservative on maximum current, but who knows.

I am guessing deep discharge, heat or a combination of the two. The battery TMS is not active unless the car is on or plugged into L2. With the upper pack being essentially inside the car, it may get too much heat in the summer sun. At lest in Ohio it would be very easy for a car interior to get up to about 130F in the summer sun. From what I have read, much above 100F will hurt the battery. I am also wondering if maybe the lower end of the charge limit might be too low or maybe people are leaving them sit too long nearly depleted not realizing how bad that is for the battery.

I guess I will be a sample size of 1 for the low discharge theory. I rarely let my SOC drop below 20% and usually charge immediately if I do. So if I end up having a leaky battery that would seem to contradict low discharge as being a cause.
 
You can see output limits during operation in ForScan. It shouldn't be able to go much beyond 4 or 5C for the peak discharge rate, which should not be problematic for a Lithium chemistry.
 
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