556 fires in three years, six dead and a call-out every other day. We speak to the firefighters and doctors struggling to cope with a deadly new epidemic.
556 fires in three years, six dead and a call-out every other day. We speak to the firefighters and doctors struggling to cope with a deadly new epidemic.
Not quite. Lithium ion batteries have 2 advantages. Massive capacity (per kg) and a very low internal resistance. The latter is amazing for getting bursts of power, with little to no voltage sag. Unfortunately it’s also the reason failures are so spectacular.
A lithium ion battery can dump a huge amount of energy (internally) in a short time. This leads to spectacular amounts of heat and fire. Other lithium chemistries are not so volatile.
E.g. lithium iron phosphate batteries have a small hit to capacity (about 80%) and a lower peak current. Their ability to self destruct is far less.
In short, it’s the combination of the amount of energy and how quickly it can dump out in a failure mode.
I feel bike batteries don’t need to dump power quickly due to their nature, but I have been wrong before.
They need a moderate spike to get the motor moving, then a steady current to keep it going.
E.g. my ebike is 250W @ 36V. That’s 7A at full (continuous) power. A lithium ion battery can be discharged at around 10C while a lifepo4 battery can only do 1C discharge. My 13Ah battery could handle it, even with the 20% capacity loss at 0.67C (7/(13*0.8)). A 500W version would exceed the battery rating however, if it’s lifepo4, while being fine with lithium ion.
Basically, lifepo4 batteries could handle a low end ebike, but would likely still want some super capacitors for spikes. They would need to scale up significantly in size to handle more powerful motors.
Oh im learning something! Ill look into this!