ORA battery strip

[brendon_m]

Had the pleasure of stripping a GWM ORA battery today, no video but I did get some photos

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Came in quite a large box but the battery insde was (relatively) small. The packaging had CATL written all over it so I'm guessing they are the cell manufacturers.
The lid appears to be a very thin layer of carbon fiber that is bolted down with a gasket (no glue or silicone)
Underneath is another bolted on panel, steel this time. Which after being removed, gives you access to the cooling plate which covers the whole bottom of the battery as 1 big piece.

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Liquid cooling ports, HV connection and 12V power/communication

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The pack is 47.8kWh. Made up of 131Ah LFP cells configured in a 1p 114s layout. Nominal voltage is 364.8V and there are 3x 18s modules and 5x 12s modules. All the busbars in each module are welded (laser welded I think? I'll need to have a closer look) with flexible circuit boards attached to the cell tops for the cell monitoring. All the cell monitoring goes to plugs at the outside edge of each module where it then connects to a harness which leads to 2x large BMS ECUs mounted in the centre. There is a small 3rd ECU in the middle as well, not sure what that is yet, I suspect it's an interface module to take messages between the BMS and the rest of the car. Contactors are controlled by the BMS directly and there is both a hall effect style current sensor and a current shunt inside the contactor assembly

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[brendon_m]

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The modules are glued down to the cooling plate. The cooling plate was not only screwed down but also had nutserts going through it that also clamped it to the case.
Ended up having to flip the battery over and drill holes in the plate in order to mount shackles so we could lift the cooling panel off with a forklift and engine hoist while using pry bars. We could pick the battery up by just the glued down cooling plate. Definitely not designed to come off.
Heat and solvents seemed to have no effect on the glue, but maybe we just never tried the right chemical.
It was some hard set resin type stuff, felt like PVC pipe

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Allegedly GWM are training their techs to replace individual modules but unless they have a specific solvent I don't see how that's feasible.

[jonescg]

It's also generally unwise, since the cell characteristics will be hard to match. For infant mortalities, maybe.
But if it's well made, the need for replacement is low.

[apterafan]

Why was the battery stripped? History?

[brendon_m]

Faulty cell possibly caused by the BMS but more likely the cell itself. It was sitting 0.3V lower than the rest.

My colleague found the glue holding the modules down goes soft at about 55°C. We tried using a heat gun at the time but we were too scared of damaging the cells so didn't apply too much heat.
The official dismantling procedure is probably along the lines of flow hot water through the cooling plate for 10 minutes and then simply lift each module out one by one rather than be a butcher and pry the cooling plate off the bottom

[apterafan]

Faulty cell possibly caused by the BMS but more likely the cell itself.

Ta,
Vintage? Odometer?
Have you any found battery monitoring apps that work?
I tried MeowEV without luck - too long ago to remember what went wrong.

I think I've only seen about one other Ora per month so I wasn't expecting to hear about any dead ones so soon.

My battery is NMC so it may be a little different.

[brendon_m]

Faulty cell possibly caused by the BMS but more likely the cell itself.

Ta,
Vintage? Odometer?
Have you any found battery monitoring apps that work?
I tried MeowEV without luck - too long ago to remember what went wrong.

I think I've only seen about one other Ora per month so I wasn't expecting to hear about any dead ones so soon.

My battery is NMC so it may be a little different.

No idea on the history or good apps unfortunately