Well..
Alta webpage says, quote ..
"Our stacked, honeycomb architecture allows for extreme energy density
at 185 watt hours per kilogram.."
The current, old, 18650-C Tesla battery is 260 wh/kg cell level.. or
about 20% more.
== 100 kWh / 500 kg for packs.
The current new 2170 Tsla/pana cell is 380 Wh/kg, about 100% better than
alta at cell level.
The number came out in some financial presentation in Feb. 2017, +/-.
Also, of note is that the alta pack is tiny, only 5.h kWh in a
metal-shelled enclosure.
Thus, they do not, and cannot, scale up to large capacities, because
there is a power-of-three relationship with mass/volume/cooling.
It is relatively easy to make tiny batteries, with mostly-passive cooling.
Alta, and lions with drones do this all the time.
When you only have the 5.8 kWh, the total energy is so low, that you
don´t melt the casings/kill the cells/etc. from losses.
If the 2017-model Tsla P100D is 96% efficient, as is more or less the
case, at 100 kW output (max == 300 kWH !) = 4 kW of power in heat and
losses.
This is a decent induction heater, and will melt metal cases in a few
minutes.
Providing actual cooling of 4 kW power on an ongoing basis is
non-trivial, ie hard to do.
E.
If the alta 5.8 kWh pack loses the same 4%, total losses are 232 W,
nothing, and the metal shell will likely provide sufficient passive cooling.
A toaster might be 1000-2000 W, ie the alta pack needs to lose about 6
times less heat than a 30€ toaster.
5.8 kWh =/= 100 kWh at all.
It is a geometric relationship, until You are able to demonstrate a
scalable system.
But the alta is still very good !
On 24/06/2017 11:10, 66b6dcd5b59507e7d751ea81382ea1f6 wrote:
> I know Hannu has often said the Tesla battery is the best in terms of
> this message subject and ref:
> http://batteryuniversity.com/learn/article/battery_definitions
>
> However Alta claim otherwise. Maybe it's because they quote the pack
> rather than the cell? Either way this pack looks as though it would be
> great for an electric boat, although the gravimetric density is less
> critical than in a motorcycle. Maybe in that sense, if choosing
> Lithium, the BMW i3 battery is a good bet with its 9 year capacity
> warranty.
--
-hanermo (cnc designs)
Posted by: Hannu Venermo <gcode.fi@gmail.com>
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