Battery Protection Solutions

Ford Focus Electric Forum

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Mar 5, 2020
I'm back in the market for a Ford Focus Electric, and in doing my research, I found some owners who ran into coolant leak issues resulting in battery failures. Those who were able to get them replaced under warranty were inconvenienced to say the least, and those who were stuck with the bill likely gave up on the car and are swearing never to buy a Ford ever again.

Is there a way to prevent this failure from occurring? Are there other common failure points I can perform preventative work on to ensure my potential FFE has a long life?
I'd suggest to stay away from the 23kwh battery or the 2012 to 2016 model years. It seems that the older battery expands and causes the coolant leak. Honestly, i don't know if the chemistry of the 33kwh is immune or just needs more time to fail... But it seems to be accepted that the older battery has the potential to fail. I don't think it is preventable, but not everyone has the issue although more and more are popping up. There are ways to detect it, but once it happens, the only fix that had been tried is drying out the internals of the battery and bypassing the coolant. One user used Flex seal to repair, but i haven't seen the repair of that.

Anyway, I'm sure other have more to add, but those are my thoughts.
I don't believe the chemistry changed. Do you have any reference for that?

You can bypass the battery and drain the coolant so there is nothing to leak - but you lose battery conditioning.

You can try to implement the fluid detector idea we've thrown around, so you can keep battery conditioning and intervene before a leak actually damages something.

The latter seems to be the better option if a failure hasn't already happened.
I just read somewhere that the battery chemistry was different; or at least I thought I did.
At least something has to be different because the capacity is 10KWhs more in the same space. Looking at Skyguy's fix of his 23KWH pack and then at my 33KWH pack, I didn't notice anything different in its construction.
You'd think, but you have to remember that the original model would have been designed around cells that already existed at least a few years before it started manufacture in 2011. And there are plenty of cells that managed to squeeze a 50% capacity bump without a chemistry change, given several years to refine the internal cell design.

We know the first was LG Chem NMC and that's effectively become the standard across the industry, though Ford announced they were adding LFP to the portfolio about 6 months ago

That isn't to say the newer one isn't less likely to fail. They could have updated the design of the module frames to better handle ballooning cells and they could have tweaked the coolant components to make them a little less likely to break - but that's purely speculation on my part.

Working with more capacity also means the cycling wear will be a little less severe, so they may have not yet gotten to the point of frequent failure.
Thank you all for the responses.

I did some more digging around, and this Russian video was especially interesting. You can turn on the captions and set them to auto-translate if you don't understand Russian:

The cooling system's Achilles heel appears to be the plastic junction piece cracking. You can see the flex-seal repair at around 14:50.
During the teardown, you also see lots of inflated pouch cells. The guy said he couldn't source any new cells even from Chinese suppliers. The video is two years old and, in the comments, he says the used cells he was able to source to replace the inflated ones ended up going bad as well. Doing some quick googling, I've also noticed that the only people selling Ford cells are selling salvaged units.

It boggles the mind how Ford, as a traditional OEM, would make a nice serviceable battery pack with removable connectors, fasteners, and modular sub-assemblies, and yet make it impossible to order components, effectively making the pack totally unserviceable. They could have avoided so many expensive warranty claims by providing a path to customers and dealers to install a more robust cooling hose junction, and to order groups of cells.

This article provided some good information on the cell groups:
Ford didn't make it. They are bought as finished assemblies from a partner.

That partner is almost certainly the entity that would be doing any remanufacturing - Ford doesn't want anything to do with repairing internals on a pack.

So that's really it - it CAN be fixed - but Ford has no repair info to give, the LGChem cells are only sold to OEMs and other parts may or may not be attainable.