Those protections only protect against external influences. One of the prime ways for these batteries to fail is due to metal particle impurities within the electrolyte during manufacturing. This can lead to those metal particles eventually short circuiting the cell internally. The risk is small but there.
As for diverting the side cam thread Dashmallow, around 2 pages ago, I apologised to KamKar for the slight diversion, and quite clearly said, there are risks that people should be aware of and people should take precautions, but it's also individual choice as to the risk. It's quite obvious that battery power banks storing huge amounts of charge and that sit in cars exposed to direct sun are far more at risk than small batteries internal to a camera. The diversion could have stopped there.....[/QUOTE]
"Slight diversion"??!
So you post at least five times to this thread with alarmist statements and sensationalist videos about a subject that belongs over in the dedicated battery forum and then because you add a little disclaimer apology about the inappropriate posts you think that should be the end of the discussion? This is an internet forum my friend and it would be naive to believe that if you post numerous provocative remarks that you won't elicit a response from someone.
Speaking of eliciting responses you apparently and unsurprisingly have no idea about what actually causes lithium battery failures. The notion that the
primary factor causing lithium battery fires is
"metal particle impurities within the electrolyte during manufacturing" is inaccurate. While foreign particles in the electrolyte can indeed be an issue, today's advanced manufacturing techniques have dramatically ameliorated this problem. The actual
primary cause of lithium-ion battery thermal runaways and explosions is the formation of
dendrites (spiky whiskers of lithium) and lithium metal plating on the separator wall that precipitates out of the electrolyte as a result of stresses such as hard charging, discharging, temperature extremes, vibrations, shock, etc. The build-up of lithium metal within the electrolyte can penetrate the separator membrane inside the battery leading to a short. Lithium metal burns hot and fast and when it comes into contact with the air it will cause the lithium saturated electrolyte to burst into flame.
The notion that battery protection circuitry only protects against external influences seem equally absurd and inaccurate. When battery voltage is too high or too low for it's rated specs the protection circuit is monitoring the conditions
within the battery. When a battery overheats, it is the cell's electrolyte that is getting hot. When a battery experiences a short, either external or internal, the circuitry will cut off any current entering or leaving the cells, etc. (although once in progress a thermal runaway cannot be stopped)
As for your notion that "
battery power banks storing huge amounts of charge and that sit in cars exposed to direct sun are far more at risk" consider that the Tesla Model S runs on 5,375 or 7104 individual 18650 3.7V lithium-ion cells (same cells as in most power banks) depending on the car model version's kWh rating.