I thought I’d post a few pictures of the Li-Ion battery from a Q50 Hybrid.
The battery is composed of 96 cells housed in 12 modules, 8 cells per module.
I haven’t had the opportunity to disassemble a module but may once this vehicle is repaired.
Here’s the battery out of the car, partially disassembled. Li-Ion battery controller is off and I was in the process of removing the bus bars.
Just the modules left, mounted to the housing.
Three of the modules were in the 0.5V range, the rest were 0.0V.
I wouldn’t mind getting my hands on a single healthy module, it’s be great for setting up some solar powered outdoor LED lighting.
The vehicle only has about 5k miles, the battery didn’t fail, it was killed!
The vehicle was towed to the dealer for a stalling/misfire issue. A series of errors in diagnosis eventually led to the dead battery.
In the end the root cause of the original problem was a gas tank full of water. The water didn’t kill the battery, just started the chain of events.
There’s no protections circuits in the modules themselves. The LBC (Lithium-Ion Battery Controller) was removed prior to photos. The LBC monitors pack voltage, current, temperature and the voltage of each cell. Target cell voltage deviation is 200mV.
If I have the time I may open a module, I’ve seen pictures of the cells but haven’t had my hands on one yet. They’re flat cells, similar looking to Li-Poly cells but much larger.
Considering the cost I doubt I’ll have one in my basement any time soon.
Must of taken some skill to kill that battery pack, since I imagine the battery controller’s job is to prevent such damage from happening. Sad to see such waste. Let me guess, an old school mechanic that wasn’t properly trained on hybrid technology?
Do you have a hobby charger? If you can get your hands on one of those cells, it may be worth trying to precharge it at very low current to see if it can be revived. Use long leads and a fireproof container though.
Not at all, actually a very competent master tech was working on the vehicle.
Hybrids just haven’t been around long enough (particularly for Infiniti technicians) to build up the wealth of common knowledge needed for accurate diagnosis. This vehicle is a good example.
If a common, internal combustion engine vehicle was towed into the shop with contaminated fuel it simply would not start. The tech cranks it and knows it’s not running, even though now an then enough fuel builds up in the front exhaust to cause a back-fire.
With a hybrid the HV motor “cranks” the engine at close to 1,000 RPM. With today’s push button start systems there’s no key to turn or button to hold down, push once and the engine starts, or so it seems. The hybrid will crank for about 45-60 seconds until the ECU detects it’s not starting.
During that time the engine sounds just like it’s running, in this case back-fire in the exhaust and a loud clatter that sounds like major mechanical damage. The noise is the coupler between the IC engine and HV motor when the occasional cylinder fires.
The technician thinks the vehicle is running, chewing up hard parts and eventually stalling. He checks the oil, looks for a hole in the block and eventually tries again.
It doesn’t take to many of these cycles to run the battery down to where the Li-Ion battery controller cuts it off.
That was only the start of miss-steps with this vehicle but I can’t blame the tech, there’s much to learn still and it’s the kind of thing you only learn by experience.
The only reason I recognized it right from the get go is I’ve seen it before. A few years back I was the one pushing the button and thinking an Altima Hybrid was starting and stalling.
