DaveinOlyWA wrote: ↑
Fri Oct 16, 2020 11:31 am
SageBrush wrote: ↑
Fri Oct 16, 2020 11:14 am
DaveinOlyWA wrote: ↑
Fri Oct 16, 2020 10:02 am
OIC. You are referring to the "other" fires. Yeah, one was bad wiring, another was out of code EVSE install and another originated elsewhere in the garage and the car was simply in the wrong place at the wrong time.
NO, I am saying that battery manufacturing defects that lead to a higher fire risk do not have to have anything to do with the TMS. Actually, I am not aware of *any* battery fires due to the TMS. So your statement that that the fires reflected a trade-off in having a TMS is at best ignorant BS with a heavy dose of FUD
So the presence of TMS has allowed manufacturers to push the limits of the batteries? Perhaps. Manufacturing defects is the likely culprit here and saying the additional complexity of adding TMS isn't a factor is "interesting"
More BS. I'm saying you cannot possibly know until the investigation into the Kona is published. In the meantime you are welcome to post past investigations that have implicated the TMS as the cause or major contributor to the battery fire.
From my reading (I am not an EE), while Li-x battery fires in EVs are rare compared to ICE vehicles, they have occurred from either cracked wire insulation of disruption of the electrodes separator, both leading to shorts. You will notice that neither major cause has squat to do with the BMS. Moreover, water extinguishes Li fire so the BMS is in fact a fire retardant.
So where is the sliver of truth in all your nonsense (there has to be something, right ?) Well, LMO battery chemistry has a higher flash point than NMC. That lets Nissan build a cheaper battery without TMS but it carries the trade-offs of worse degradation and low power DC fast charging. An LMO battery with TMS would have less fire risk than an LMO battery without TMS. In a similar fashion, an NMC battery with hobbled max current will have a lower fire risk than one used in a high power environment like a Tesla.
In summary, the TMS adds safety. LMO is inherently safer than NMC but it carries performance penalties when used as a cost cutting device.