From a Electrical engineering perspective, the mean time between
failures of 6800 cells is terrible but you can lose a lot and still have
a functioning car, so I recon he is probably right, but it depends of
the MTBF of the 2 types of cells too. I used to design electronics for
military, (submarines) you can make MTBF say whatever you want! nowdays
they use FMEA (failure mode and effects analysis) too, that this would
show what really happens.
you could say "if you lose one cell with large format then the car
is immobilized but you could lose 3400 cells with small format, so it's
3400 times better".
On 09-Sep-18 1:34 PM, mark hanson via EV wrote:
Hi Bob etc,
Consumer Reports said while they loved driving a Tesla model S, they gave it
a poor rating on reliability and preferred the Leaf and now the Bolt, saying
"you'd be nuts not to consider a Bolt". Elon Musk/Tesla is the *only*
company that's putting 6800+ 21mm X 70mm itty bitty cells together in a
large EV. When they came out with the Roadster in California, I asked a
Tesla salesman about the long term reliability of 6800 points of failure and
he said "don't think of it as 6800 points of failure, think of it as 6800
points of redundancy". Good spin. Either they know something that *no*
other large scale vehicle manufacturer/engineering teams doesn't, or their
long term reliability/profitability will continue to be poor. Knowing what
I know about electronic componentry, I'll put my money on large format cells
for large on road EV's, Bolt, Leaf, Smart, BMW etc.
Note for further info, see: www.Batteryuniversity.com EV battery
comparisons/lithium chemistries LMC Cathode, vs LiFePO4 & aluminized cathode
(tesla type) cells.
Best regards,
Mark
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