yardbird88 said:
A client of mine who is both an electrical engineer & chemist told me that The Tesla batteries are just a bunch of little lithium (like your AA batteries) sticks, nothing high tech because they can mass produce those and bundle them together. It is probably similar in our PHEV. He said once it caught fire, you can't stop it with water because it makes the fire worse. However he told me not to worry as the chance of overheat and fire is pretty small just like your iphone's.
Tesla use 18650 / 21700 lithium cells ... possibly 3.6v nominal voltage .. each cell is 3.4Ah / 5Ah .. they need around 7000/3000 (3000 on model 3) of these for make the full battery pack
Our PHEV use big prismatic cells. nominal voltage is 3.75v .. and we have only 80 of these big cell in our PHEV .. and only 600 of these would be needed for make a 100kwh pack like on a Tesla S100
So ... a very different technology used between Mitsubishi and Tesla
Our battery pack should be water proof, people crossing on deep water will cause to fully submerge our pack ... I would not gamble on the water proof safety of our pack, but so far nobody reported any issue
About eventual fire ... even if it is just 12kwh pack ... it is just good to remember that the Rimac Concept One destroyed by Grand Tour, got on fire short after the crash, and was burning for over 1 week.
Back to the question if it is dangerous to charge the car in a garage :
- There is not a single accident
- Unless battery degradation is very high , the risk is practically zero.
- Once the battery will be very old (10y or more), with a SOH below 40% ... then yes ... it is possible that :
Lithium metal plating inside the battery creates extremely hazardous conditions that may lead to fires or even exploding batteries
My understanding is battery degradation is mainly due to battery plating. This can cause a short and eventual fire/explosion especially when the battery is fully charged
I believe the BMU might prevent the charge of our battery if battery degradation is too high .. so before the car can go on fire, I believe it will refuse to get any charge or it might reduce the max charging voltage from 4.1v down to 4.0v ...or even less
Another difference between Tesla and Mitsubishi .. it is that the tesla has 70/50 battery in parallel .. so if one goes bad, it has many cells in parallel which might cause a burst on current flow from the good cells into the bad one .. but for prevent this, they have a simple "fuse" on each cell, that will melt in case of high current flow
Since out PHEV has only 80 cells in series, and none in parallel .. we don't have this issue .. but a big cell can still fail inside and since it is big, it has lot of energy which might cause fire or explosion