On 21/05/2021 08:25, Ian wrote:
On 2021-05-20, Dave Plowman (News) wrote:
In article ,
williamwright wrote:
By the time we are forced to EVs, they will be available with the same
range as any current diesel car. In other words, as far as any normal
person would wish to travel in one day by car.


****ing hell! Mystic Meg speaks!

Have you not noticed the increase in range in the short time EVs have been
around? And think it impossible it will get even better?

Sure, it will get better, and will (have to be) good enough, as it's been
decided that this is the way we're going, and a lot of people are going to
make a lot of money from the tech. refresh, even if the end result makes
us worse off.

A big problem is that people see the enormous advances in computers (CPU speeds,
storage capacity, network speeds), and think the same advances will happen to
batteries. Unfortunately a 100% increase in battery capacity¹ would be a major
breakthrough, we need 1000% ^ n (cf. kilobit megabit gigabit network speeds).

¹(or charge time/life time/weight/cost, or whatever other metric is important)

Any technology follows at first an exponential curve, and then an
asymptotic curve.

The first CPU I programmed clocked at 4Mhz. but te ones I have here are
all 1-4Ghz, despite the fact that the oldest one is 15 years old. The
technology is now mature and as 'good as it gets' and apart from adding
ciores it aint gonna get any better any tome soon

Lithium batteries ARE the breakthrough. In the periodic table it is at
the sweet spot of energy to weight. It is the *best* metal to use. And
currently its not good enough. We are on the asymptotic part of the
development curve, not the exponential. This is nearly as good as it
gets for electrochemical batteries. It is tantalisingly close to being
way more useful, but there's no cigar yet.

3 x improvement in energy density nets you something that would rival
fuel cars, and power cross channel ferries and even fly a passenger
plane a few hundred miles.

10 x energy density and you are in the same ball park as kerosene - and
you can fully replace fuel engines, except maybe in military
applications where uber fast refuelling and well off grid performance is
required

But unfortunately the theoretical limit is I think - I haven't checked
it - about 8 times, and that's just for electrolyte and so on - you
still need electrodes, and a case..

The flight batteries that I first bought in around 2006 are actually
*lighter* than the ones on sale today. But today's ones are tougher,
take more abuse and last longer.

The fact that electric cars have the range they do is not down to
battery improvements per se, its as much to do with using the battery
more efficiently with regenerative braking etc.

a 100kwh battery is in raw terms about 10 litres of fuel. Ok an electric
motor is about 3 times more efficient. but that's still only 30 litres
of fuel equivalent. So the 'mpg' equivalent is 6.6 gallons.

you simply would not sell a car with a 6.6 gallon tank that took an hour
to fill up

And in fact many batteries are 50kWh...

the jaguar I pace is around 84 usable kWh allegedly and does a shade
over 200 miles well that's 200 miles on 5.5 'gallons' - not that great.

But even that on a big heavy car is a tribute to regenerative braking
and aero...

....its almost impossible to break the 100mpg mark for anything remotely
car shaped, and even 70mpg is doing well. Car development is pretty much
mature - there aren't any more great gains to be had.
The fact is that when you drill down through the crap what is left is
that you need a certain amount of energy to push a car shaped car on
tyres on tarmac at a given speed, over a given distance, and that the
bigger battery you carry the heavier the car and the more energy it
takes....

We need 300kWh batteries. To do 600 miles. The I-pace battery is 600kg
In a vehicle that weighs 2200kg. so about one third the weight of the
car. If it were 300Kwh it would be around 2200kg so the car would weigh
nearly double, using twice the energy to get up to speed every time it
stopped. And you never get all the energy back through regen braking.
Only at a constant speed would it have three times the range.

The best (lightest) raw pack for flight I can find - no real case, no
protection circuits - would net out at 1.7 tonnes in sufficient quantity
to do 300Kwh. Jaguar are *already* nearly as good as it gets.

We are nearly as good as it gets - as it *can* get. And its not quite
good enough to make the electric car mainstream. In an urban/suburban
situation as a second car, plugged in every night, to do the school and
supermarket runs, its fantastic.

It's even ok for a one hour commute ..but not much more.

And the cost! And the materials! RC flight batteries are 50p per watt
hour give or take. 300kw would be about £150,000...just for a 600 mile
range battery - now I am sure that jaguar can buy cheaper than that but
still - expect £75000 worth of battery to be attached to your car.

Makes nicking the exhaust for platinum look like kindergarten stuff.

let's say that 2/3rd of the battery weight is lithium...a tonne say..the
spot price of the raw material is $13/kg so that $13,000 just for the
raw lithium.

lets also say that we end up with 20 million cars on the roads not to
mention the lorries..so 20 million tonnes of lithium to 'net zero' the UK.

That's one quarter of the total known reserves in the world...

and and 500 times the annual production of the worlds biggest producer -
Australia.JUST FOR THE UK

Seriously, it ain't gonna happen. Not with lithium batteries anyway.

Either we lose electric cars altogether, or we accept severe
restrictions on personal travel.

Unless someone comes up with some as yet undreamed of energy storage
technology, and it would have to be something in the quantum level of
things, because we have explored all the other bits of science well
enough to know there ain't no more answers there.

Its a shame. I would love a 300bhp 600 mile range 5 minute recharge
electric car for under 20 grand.

As it is I'll stick with my turbodiesel jag, which does all of that.


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