Chip with simple program for Toy

[ian field]

"Jasen Betts" <jasen@xnet.co.nz> wrote in message news:gaip33$33q$3@gonzo...

On 2008-09-14, Paul E. Schoen <pstech@smart.net> wrote:
It might be prudent to add a neon lamp or a TVS bidirectional zener type
suppressor across the scope inputs. I'm not sure how fast a neon lamp
triggers, but the type of suppressors used in telephone equipment should
be
pretty good, and rated about 60 volts.

at 60 they'd fire on the ring voltage.

Bye.
Jasen

Might not be so bad if the OP builds a scope lead breakout box to add the
neon so it can be shunt connected between a x10 probe and the scope input.

 

[ian field]

"Jasen Betts" <jasen@xnet.co.nz> wrote in message news:gaip33$33q$3@gonzo...

On 2008-09-14, Paul E. Schoen <pstech@smart.net> wrote:
It might be prudent to add a neon lamp or a TVS bidirectional zener type
suppressor across the scope inputs. I'm not sure how fast a neon lamp
triggers, but the type of suppressors used in telephone equipment should
be
pretty good, and rated about 60 volts.

at 60 they'd fire on the ring voltage.

Bye.
Jasen

Might not be so bad if the OP builds a scope lead breakout box to add the
neon so it can be shunt connected between a x10 probe and the scope input.

 

[ian field]

"Jasen Betts" <jasen@xnet.co.nz> wrote in message news:gaip33$33q$3@gonzo...

On 2008-09-14, Paul E. Schoen <pstech@smart.net> wrote:
It might be prudent to add a neon lamp or a TVS bidirectional zener type
suppressor across the scope inputs. I'm not sure how fast a neon lamp
triggers, but the type of suppressors used in telephone equipment should
be
pretty good, and rated about 60 volts.

at 60 they'd fire on the ring voltage.

Bye.
Jasen

Might not be so bad if the OP builds a scope lead breakout box to add the
neon so it can be shunt connected between a x10 probe and the scope input.

 

[ian field]

"Jasen Betts" <jasen@xnet.co.nz> wrote in message news:gaip33$33q$3@gonzo...

On 2008-09-14, Paul E. Schoen <pstech@smart.net> wrote:
It might be prudent to add a neon lamp or a TVS bidirectional zener type
suppressor across the scope inputs. I'm not sure how fast a neon lamp
triggers, but the type of suppressors used in telephone equipment should
be
pretty good, and rated about 60 volts.

at 60 they'd fire on the ring voltage.

Bye.
Jasen

Might not be so bad if the OP builds a scope lead breakout box to add the
neon so it can be shunt connected between a x10 probe and the scope input.

 

[ian field]

"Jasen Betts" <jasen@xnet.co.nz> wrote in message news:gaip33$33q$3@gonzo...

On 2008-09-14, Paul E. Schoen <pstech@smart.net> wrote:
It might be prudent to add a neon lamp or a TVS bidirectional zener type
suppressor across the scope inputs. I'm not sure how fast a neon lamp
triggers, but the type of suppressors used in telephone equipment should
be
pretty good, and rated about 60 volts.

at 60 they'd fire on the ring voltage.

Bye.
Jasen

Might not be so bad if the OP builds a scope lead breakout box to add the
neon so it can be shunt connected between a x10 probe and the scope input.

 

[ian field]

"Jasen Betts" <jasen@xnet.co.nz> wrote in message news:gaip33$33q$3@gonzo...

On 2008-09-14, Paul E. Schoen <pstech@smart.net> wrote:
It might be prudent to add a neon lamp or a TVS bidirectional zener type
suppressor across the scope inputs. I'm not sure how fast a neon lamp
triggers, but the type of suppressors used in telephone equipment should
be
pretty good, and rated about 60 volts.

at 60 they'd fire on the ring voltage.

Bye.
Jasen

Might not be so bad if the OP builds a scope lead breakout box to add the
neon so it can be shunt connected between a x10 probe and the scope input.

 

[ian field]

"Jasen Betts" <jasen@xnet.co.nz> wrote in message news:gaip33$33q$3@gonzo...

On 2008-09-14, Paul E. Schoen <pstech@smart.net> wrote:
It might be prudent to add a neon lamp or a TVS bidirectional zener type
suppressor across the scope inputs. I'm not sure how fast a neon lamp
triggers, but the type of suppressors used in telephone equipment should
be
pretty good, and rated about 60 volts.

at 60 they'd fire on the ring voltage.

Bye.
Jasen

Might not be so bad if the OP builds a scope lead breakout box to add the
neon so it can be shunt connected between a x10 probe and the scope input.

 

[Jon Slaughter]

"Simon Morden" <simon.morden@spamtastic.blueyonder.co.uk> wrote in message
news:f2szk.96004$1l2.75459@newsfe27.ams2...

I'm trying to remember my limited 20-year old electronics knowledge and
failing miserably...

Some background: the school I work at is involved in a science competition
run by Rolls Royce. Our project is to make a wind tunnel and test turbine
designs. I am in charge of the instrumentation.

The problem: I need to be able to record the rpm of the test pieces.

What I've done so far: I have availed myself of the National
Semiconductors' LM2917 (14-pin), as detailed here:
http://www.national.com/mpf/LM/LM2917.html
It's a dedicated frequency to voltage IC, and I'm running it off a 9v
battery. I've set it up so that it works - I can input an ac voltage and
get a proportional dc output.

What I can't do: I can't make my rpm detector talk to the chip. The
detector set up is a bike computer sensor and a 3v battery. Output is
pulsed dc which does not fall below ground - and the chip requires that
pin 1 goes at least -30mV on each cycle.

What I can't do (part2): I know I have to use something like capacitor
coupling to strip out the dc and keep the ac. I know I have to keep RC<T
because I'm trying to just get the voltage spikes +/-. What I really can't
do is make what on the face of it should be a really simple circuit to
convert the pulsed dc train (at 10-100 Hz) into a pseudo ac voltage with a
large enough variation to fool the chip.

Read the 2nd paragraph on page 7. You need to set up the chip to use dc.

It has a comparator that can be setup to be ground(or actually a bit above
ground) and it says something about hysteresis in their too.

Optionally you could shift the voltage of the pulsed dc down by using a
negative supply or possibily shifting the ic chip up. e.g., put a diode on
the ground pin or use an active resistor(if the ic doesn't pull enough
current for the diode to turn "on"). The output signals will all be shifted
up of course but you can unshift them. At least this should work in theory

 

[Jon Slaughter]

<mluttgens@wanadoo.fr> wrote in message
news:04746a31-2c53-4614-9562-f520585d6cea@59g2000hsb.googlegroups.com...

EM pulse detection

Is it possible to measure with great precision the time
at which a very short EM pulse reaches a receiver situated
at some distance from the emitter?
The time should be recorded on the emitter's clock and
also on the receiver's clock.

If you have ideal measuring devices you can! The error is going be in
generating the pulse and recieving it(assuming any dispersion is
irrelevant).

It think you need to give more information about such things as in general
the lower the frequency the less well defined a "pulse" is. (i.e., a square
wave pulese has infinite frequency and is "exact" but a sinewave has one
frequency and is inexact)

You might combine different methods of testing and such but you need to
determine what "great precision" is and how you can calibrate your system to
check your "great precision".

I think your question is just to general to get any specific answer.

 

[Jon Slaughter]

<mluttgens@wanadoo.fr> wrote in message
news:4d4a2275-ea9a-41d5-97e7-b56ce28badde@l64g2000hse.googlegroups.com...
On Sep 15, 3:17 pm, "Jon Slaughter" <Jon_Slaugh...@Hotmail.com> wrote:

mluttg...@wanadoo.fr> wrote in message

news:04746a31-2c53-4614-9562-f520585d6cea@59g2000hsb.googlegroups.com...

EM pulse detection

Is it possible to measure with great precision the time
at which a very short EM pulse reaches a receiver situated
at some distance from the emitter?
The time should be recorded on the emitter's clock and
also on the receiver's clock.

If you have ideal measuring devices you can! The error is going be in
generating the pulse and recieving it(assuming any dispersion is
irrelevant).

It think you need to give more information about such things as in general
the lower the frequency the less well defined a "pulse" is. (i.e., a
square
wave pulese has infinite frequency and is "exact" but a sinewave has one
frequency and is inexact)

You might combine different methods of testing and such but you need to
determine what "great precision" is and how you can calibrate your system
to
check your "great precision".

I think your question is just to general to get any specific answer.

Thank you for your remarks
The aim is to measure the speed of light. I don't know
if there are devices having the required precision.

Marcel Luttgens
-------

Is their any specific reason why? It is well known that c = 299792458 m/s.

Chances are you'll be better off using indirect methods

http://en.wikipedia.org/wiki/Speed_of_light

I really don't see any reason why you would want to measure the speed of
light as it has already been done and probably to a much greater precision
then you will ever be able to do by yourself.

 

[Jon Slaughter]

"Simon Morden" <simon.morden@spamtastic.blueyonder.co.uk> wrote in message
news:C%yzk.31240$t_1.2937@newsfe30.ams2...

Jon Slaughter wrote:


Read the 2nd paragraph on page 7. You need to set up the chip to use dc.

It has a comparator that can be setup to be ground(or actually a bit
above ground) and it says something about hysteresis in their too.



You star. My only excuse (and I'd read that document *and* the AN-162
applications pdf) is that I'm a geologist by trade, and only picked up the
physics I needed...

I now have the sensor and the chip talking to each other, with only one
more problem to solve - it only works when I have a voltmeter between pin
1 and ground (I was measuring V(in) so I could balance the V(bias)). I
have a feeling a M-ohm resistor will do the trick, but not sure why.

But I've stopped the night - I can't see the numbers on my capacitors
anymore.

Well, try it and see If it works then it works I'm not sure what is
going on though. Maybe adding just enough capacitance to the circuit or
something else? It could be acting as a pulldown to ground which is needed
if the input ends up floating for some reason.

 

[Rod Speed]

Bret Cahill <BretCahill@aol.com> wrote:

The pursuit of a "super" battery that could cheaply and efficiently
store energy all at a high density might not be the best use of time
and resources.

A more plausible solution would be a system of several different
batteries with an electronic controller which would charge and
discharge the various batteries depending on the source of power.

Instead of wasting expensive fuel charging inefficient batteries or
expensive batteries repeatedly being cycled with cheap grid
electricity, a controller would have inputs for fuel cost, grid cost
and battery costs and then automatically shift between the various
batteries to cut costs.

For example, if a plug in hybrid was being used mostly as an EV, then
the controller would run the energy through the low cost (< 15 cents/
kW-hr) cells where the efficiency only needs to be above 60%. When it
was time for a long road trip the controller would shift to the 95%
efficient cells that might be cost effective even above $2/kW-hr.

Thanks for that completely superfluous proof of why no one
has ever been stupid enough to employ you as an engineer.

 

[Rob Dekker]

"Bret Cahill" <BretCahill@aol.com> wrote in message news:9a8b2695-fc66-4db1-909b-3f4b96048f3b@a18g2000pra.googlegroups.com...

1. High efficiency, energy and power density (600 W/kg); cost /
cycling life only needs to be below $2/kW/hr.

2. Low cost (< 10 cents/kW-hr); efficiency, energy and power density
might not be too good.

3. Low cost, high energy and power density; Efficiency only needs to
be above 60%


Bret Cahill

There are wonderful batteries out there, and advances are made constantly, to many types of rechargable electro chemical cells.

One of the interesting ones I looked at lately is the (stabilized) Lithium Sulfur battery. Example development :
http://www.sionpower.com/pdf/articles/PowerSources2004.pdf
Gets 300 Wh/kg energy density currently, and there is little in the way of going to 400 or 500 Wh/kg. Power density is adequate for
EVs, and low temperature (cold wheather) behavior is excellent. If Lithium becomes scarce, there should be little problem switching
to another alkali metal such as Potassium or Sodium, with only small reduction of energy density. On the downside, recharge cycle
lifetime is still poor (250 - 500 cycles) and cost is high right now. But as always, volume production can change cost.

A really low cost, high capacity cell, with great power density and many (thousands) of lifetime cycles is the 'good old' Sodium
Sulfur battery.
Theoretical energy density is about 800 Wh/kg, current cells operate at around 250 Wh/kg.
Opponents claim safety issues are the main problems for this battery. These problems can be addressed, but it is doubtful that
automotive manufacturers will use this cell in large volumes, simply because of fear of safety issues. The ideal automotive battery
might not exist, because fair and conservative thinking is in the way of high volume use....

I looked at several out-of-the-box ideas for a super battery : Here is one theoretical one : Sodium Fluoride electro chemical cells.
Theoretical energy density of 3690 Wh/kg.
Many engineering issues remain.. One big issue : We need to find a way to store Fluorine gas. This might be similar to the problem
of storing hydrogen gas in hydrogen powered vehicles. Interesting overlap of engineering issues huh ?

Rob

 

[Rob Dekker]

"Uncle Al" <UncleAl0@hate.spam.net> wrote in message news:48CC3BE7.F86D8F30@hate.spam.net...

Bret Cahill wrote:

1. High efficiency, energy and power density (600 W/kg); cost /
cycling life only needs to be below $2/kW/hr.

2. Low cost (< 10 cents/kW-hr); efficiency, energy and power density
might not be too good.

3. Low cost, high energy and power density; Efficiency only needs to
be above 60%

Bret Cahill

Find a universe with different thermodynamics and economics.

Hi Al,

We do not need a new universe or different thermodynamics to design batteries with jaw-dropping characteristics.
The current universe offers a virtual infinite amount of ways to make batteries.

Even in the (one) group of alkali-halogen salt electrochemical cells there are amazing possibilities. For example Sodium Iodine has
a theoretical energy density of 600 Wh/kg. Sodium Chloride (table salt) can store 1913 Wh/kg and Sodium Fluoride (the stuff in tap
water to prevent cavities) checks in a whopping 3690 Wh/kg.

There are just immense engineering challenges to actually build such cells. Engineering difficulties, safety issues etc are the
problem. And fear of the unkown. Not the theory and not the laws of physics. Nature gave us a lot of building blocks to play with.
We are just getting started in this game....

Rob

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/lajos.htm#a2

 

[christofire]

"goldenhound" <goldenhound104@gmail.com> wrote in message
news:3d0d9f2a-6e80-4f9a-b216-eb2c39fac044@s28g2000prd.googlegroups.com...

On Sep 14, 12:14 pm, Michael Black <et...@ncf.ca> wrote:

On Sun, 14 Sep 2008, Jamie wrote:
As some one else here had provided a schematic (nice of them ), I
took
the liberty to examine it.

Very nice of them, indeed! Thank you Christofire!!

Unfortunately, the schematic referenced on DIYSTOMPBOXES was the
*Deluxe* EH Electric Mistress. Mine is just the Electric Mistress, 2
- 9v version circa 1979. I bought it brand new, but it sat for a long
time and when I pulled it out to try it, I get no sound out of it.

SO if there's no sound at the output at all, he either doesn't
have power to the devices, or something is wrong with the input
buffers (assuming the schematic he is following is about what
many websearch hits show).

To be more precise, I plug guitar into input, and plug output to amp.
With the footswitch off, I get a clean signal, footswitch on (FX
engaged), I get nothing - no sound at all. Originally, opening up the
FX I found what looked like the positve power wire from the batteries
had broken off from the PCB. I looked at it with a mag glass and
found where I thought it should go and resoldered it. Didn't help.
Maybe its in the wrong place?

That's assuming the schematic the original poster is using is the same.
We don't yet know that, it's possible he has a schematic that is labelled
as the device, when it's not. Or, there may be multiple schematics of
the same commercial device, but which come from different sources
so they are not all quite alike. Ie, if a bunch of people traced out
the circuit, and the put it on the web, there's no guarantee that they
all match since someone might have made an error in the tracing.

Michael

I scoured the net and found a couple of the schematics (that *used* to
be on DIYSTOMPBOXES.com, but have since disappeared), but I guess I
can't attach them to my posts, right? Can I upload them to someone
who is hosting so I can have a real link to show what I mean?

I'd also like to show the front / back of my PCB to show what I've
done, which may not be correct. I don't know how to relate a
schematic to the actual circuit which is probably essential, right?

Maybe these schematics aren't right? I'm not finding the components
on the PCB where I think they should be according to the schematic.

Do I understand (thanks to Jon Slaughter) that this whole problem
might be due to a bad diode, or transistor? I'm going to have to
round up data sheets on the IC's involved and see if I'm getting power
out of them.

I have purchased two $35+ multimeters (probably chinese) that claim to
be able to test transistors and capacitors, but I'll have to remove
them to test. Is this where I should start? Testing each of the
components values? Or is there a way to test them in-circuit? Or
should I pull the diodes and test them first?

Thanks to you all for weighing in on this. Maybe this effect *will*
work again someday!

Rob

You could post them to alt.binaries.schematics.electronic where schematics
and photos are more welcome, with a note relating each post to this
discussion in this NG. You might pick up a bit of additional interest there
as well.

Have you tried to find the schematic for the model you have using Google and
otherwise 'scouring' the net? ... I'd recommend it if you haven't yet.

Chris

 

[Rob Dekker]

"Yevgen Barsukov" <evgenijb@gmail.com> wrote in message news:79c01af6-55e3-41fc-9be7-2e31fc3ea179@l42g2000hsc.googlegroups.com...
On Sep 15, 4:38 pm, "Rob Dekker" <r...@verific.com> wrote:

"Bret Cahill" <BretCah...@aol.com> wrote in messagenews:9a8b2695-fc66-4db1-909b-3f4b96048f3b@a18g2000pra.googlegroups.com...
1. High efficiency, energy and power density (600 W/kg); cost /
cycling life only needs to be below $2/kW/hr.

2. Low cost (< 10 cents/kW-hr); efficiency, energy and power density
might not be too good.

3. Low cost, high energy and power density; Efficiency only needs to
be above 60%

Bret Cahill

There are wonderful batteries out there, and advances are made constantly, to many types of rechargable electro chemical cells.

One of the interesting ones I looked at lately is the (stabilized) Lithium Sulfur battery. Example development
:http://www.sionpower.com/pdf/articles/PowerSources2004.pdf
Gets 300 Wh/kg energy density currently, and there is little in the way of going to 400 or 500 Wh/kg. Power density is adequate
for
EVs, and low temperature (cold wheather) behavior is excellent. If Lithium becomes scarce, there should be little problem
switching
to another alkali metal such as Potassium or Sodium, with only small reduction of energy density.

That is highly doubtful because of inability of stable passivating
film formation on Sodium or Potassium.
In overall, Li is so popular not only because it is the
lightest of the energetic
metalls, but also because of high ionic conductivity and solubulity of
its salts.
Na and K do not share this nice property.

I agree. Lithium is almost perfect for batteries. But, IMHO Lithium is best preserved for portable electronics. PHEVs and EVs would
need something else.
Large scale use of Lithium for PHEVs would quite rapidly deplete the limited amount of lithium salt that the world has in readily
harvestable form. That would almost certainly cause a Lithium shortage and immense price hikes for Lithium. So much that an
alternative will be needed very quickly.
Sodium is far cheaper and theoretically pretty decent. So if we can overcome the challenges of Sodium, then we sure have a winning
material for the electric vehicles of the future.

Do you think that some of the issues with Sodium (and Potassium) might be resolved when we would use a nano structure (like the
Stanford nanowire design) on the anode ?

On the downside, recharge cycle
lifetime is still poor (250 - 500 cycles) and cost is high right now. But as always, volume >production can change cost.

Some processes are inherently more expensive than others. For example
CVD or othe vacuum
thin film deposition processes (used to make Li/S battery) are always
going to be more
expensive than slurry casting used in traditional Li-ion.

Sure. However, if you would have told someone 100 years ago that we could make an computation machine that contains 100 million
switching devices, that can do 1 billion operations per second, is the size of a post stamp and can be produced for about $10, then
they would have declared you a nutcase...

A really low cost, high capacity cell, with great power density and many (thousands) of lifetime cycles is the 'good old' Sodium
Sulfur battery.
Theoretical energy density is about 800 Wh/kg, current cells operate at around 250 Wh/kg.
Opponents claim safety issues are the main problems for this battery. These problems can be addressed, but it is doubtful that
automotive manufacturers will use this cell in large volumes, simply because of fear of safety issues. The ideal automotive
battery
might not exist, because fair and conservative thinking is in the way of high volume use....

Conservative thinking has its uses. As statistics of Chem.Abstracs
shows, 95% of new ideas
turn out to be counter-productive.
Does not mean we should not try new things, but we should keep in mind
that "old" things
while having well known and understood problems and limitations,
are also tested under huge test matrix of various practical
situations. New ideas are
only tested by gedanken experiments (which test matrix is in turn
limited by imagination
of the thinker).

The Sodium Sulfur battery is not really a new idea. It is also a commercial and technical success for grid-storage systems (heavily
used in Japan).
It's use in vehicles however is not likely because of fear of safety issues.
Heck, even the perfectly safe Zebra (NiNaCl) battery is not yet a huge hit yet with EVs.
Of course, Lithium price hikes can easily make the much cheaper molten salt batteries pretty darn interesting again.

I looked at several out-of-the-box ideas for a super battery : Here is one theoretical one : Sodium Fluoride electro chemical
cells.
Theoretical energy density of 3690 Wh/kg.
Many engineering issues remain.. One big issue : We need to find a way to store Fluorine gas. This might be similar to the
problem
of storing hydrogen gas in hydrogen powered vehicles. Interesting overlap of engineering >issues huh ?

Actually F2 is not that difficult to store. It passivates aluminum,
for example, and you can keep it in Teflon.


But in addition to its aggressiveness, it is the most poisonous
compounds known to man.
I doubt that anybody in clear mind would suggest putting it into cars.

It was a theoretical example. To continue the 'gedanken experiment', if we could find a cathode design with an immense surface area,
we may be able to store Fluorine gas in the atomic nooks and cracks. Maybe it would stay there even at atmospheric pressure, so that
it won't escape even if the battery gets crushed... Engineering challenge only...
If that is still considered unsafe, maybe we can store Cl2 gas, which is a lot less toxic. The NaCl system yields 1913 Wh/kg
theoretical. Enough for most people...

Rob

Regards,
Yevgen

Rob

 

[Phil Allison]

"ehsjr"

The meter is driven by current. The voltage level powering
a microprocessor will be fine, but the current *must* be
limited to less than 100 ua, per the page you posted.

Assuming a 5 volt supply, you can use a 2 meg resistor in
series to limit the current to no more than 50 uA to give
yourself a wide safety margin when testing the meter.

** Huh ???

100k is the value needed.



....... Phil

 

[|-|erc]

"herbzet" <herbzet@gmail.com> wrote >

|-|erc wrote:

"herbzet" <herbzet@gmail.com> wrote ...

Took 30 seconds to forward this in full to groups-abuse@google.com
as off-topic to sci.logic. Why don't you join me?


What's google got to do with newsgroups, they have a newsgroup reader
and they archive posts, may as well complain to the pope.

The OP is using his account at google to post off-topic crap.

Google makes money off this service and doesn't want to see it
ruined by people abusing it.

Try spending a whole 30 seconds to stop that vile crap instead
of telling me what a naif I am.

Oh he's posting from google, that makes a biiig difference. </sarchasm>

Welcome to anarchy.

Herc

 

[Rob Dekker]

"Yevgen Barsukov" <evgenijb@gmail.com> wrote in message news:86f9c8f2-db40-480b-a96b-5c665809e48a@m45g2000hsb.googlegroups.com...
On Sep 11, 10:09 pm, Bret Cahill <BretCah...@aol.com> wrote:
........

The $300 million McCain is offering is a joke.

First it doesn't even come close to covering R & D costs. Second, the
patent would be worth several orders of magnitude more.

Only Branson had a dumber offer -- $25,000,000

Bret Cahill

This is more close to what I am talking about:
http://money.cnn.com/news/newsfeeds/articles/djf500/200809121439DOWJONESDJONLINE000742_FORTUNE5.htm

25 billion is something that is going to make an impact.
However, even 25% efficiency improvement is not high enough barrier to
exclude other "non-electric" technologies.
But then, why would we want to exclude them? After all,
combination
of direct injection, turbocharging, aerodynamics and weight are all
steps in right direction. The last two will definitely benefit (or
maybe
even make economical) battery-only cars, because inherently more
efficient car will also
require smaller/cheaper battery.

Regards,
Yevgen

Thanks for this post Yevgen !

There is nothing 'electric' or 'green' or 'next generation vehicle' about this loan program.

It smells very much like an attempt to keep a catastrophically failing General Motors alive.
Only a 25% improvement needed on abysmal average milage number that GM vehicles currently have.
So if GM goes from 20mpg average to 25mpg average then they can get this 'lower than market rates' loan ?

They have to go double their gas milage or else they don't stand a chance against foreign automakers !!
We (as US tax payers) are now officially pathetic.

Rob

 

[Rob Dekker]

"Yevgen Barsukov" <evgenijb@gmail.com> wrote in message news:a854bf5d-458b-470d-8bb7-76fa694c4140@d77g2000hsb.googlegroups.com...
On Sep 15, 6:32 pm, "Rob Dekker" <r...@verific.com> wrote:
......

One of the interesting ones I looked at lately is the (stabilized) Lithium Sulfur battery. Example development
:http://www.sionpower.com/pdf/articles/PowerSources2004.pdf
Gets 300 Wh/kg energy density currently, and there is little in the way of going to 400 or 500 Wh/kg. Power density is
adequate
for
EVs, and low temperature (cold wheather) behavior is excellent. If Lithium becomes scarce, there should be little problem
switching
to another alkali metal such as Potassium or Sodium, with only small reduction of energy density.

That is highly doubtful because of inability of stable passivating
film formation on Sodium or Potassium.
In overall, Li is so popular not only because it is the
lightest of the energetic
metalls, but also because of high ionic conductivity and solubulity of
its salts.
Na and K do not share this nice property.

I agree. Lithium is almost perfect for batteries. But, IMHO Lithium is best preserved for portable electronics. PHEVs and EVs
would
need something else.
Large scale use of Lithium for PHEVs would quite rapidly deplete the limited amount of lithium salt that the world has in
readily
harvestable form. That would almost certainly cause a Lithium shortage and immense price hikes for Lithium. So much that an
alternative will be needed very quickly.

Automotive industry is very suitable for recycling. For example, Lead
from Lead Acid batteries are now the most recycled material on earth,
with 95% recycling level. Most likely it is
due to
1) inherent high level of standartization present in automotive
industry
2) strict regulations.
3) large size of batteries, which asks for a centralized handling

I think regulations for recycling of Li-ion batteries will be
tightened soon anyway, just for the safety and toxicity reasons, and
larger size of automotive batteries will allow to
achieve similar levels of recycling for Li.

Of course, recycling is essential for all vehicle components, but extra so for Lithium batteries.
However, recycling alone will not solve the looming Lithium shortage once we start using Lithium batteries for PHEVs and EVs.
Here is a report (thank you B. Richardson for the link) which outlines the supply constraints on Lithium :
http://www.evworld.com/library/lithium_shortage.pdf

There is also a follow-up report which addresses the issue in more detail :
http://www.meridian-int-res.com/Projects/Lithium_Microscope.pdf

The link does not seem to work right now, but that report shows quite convincingly that Lithium shortages will occur very soon when
volume (tens of thousands) production of PHEV batteries (with 10 kWh) batteries starts.
Considering that the world cranks out 65 million new vehicles every year, it looks like Lithium based batteries will remain for the
most affluent only in the new PHEV world.
The rest of us will have to do with batteries of a different chemical composition. Most notably the Zebra or Zn-air.

Sodium is far cheaper and theoretically pretty decent. So if we can overcome the challenges of Sodium, then we sure have a
winning
material for the electric vehicles of the future.

I would love to see some Na batteries, but challenges are immense.
Bad solubility in organic solvent, extreme reactivity, no passivation
layer,
hard to intercalate into anything.
Most likely Na batteries made in observable future will be
1) solid state thin film (because good solid electrolytes exists, like
NASICON)
or
2) at high temperature using molten Na
3) or very low rate of discharge

Thanks for info on NASICON solid electrolytes. I did not know about these.
Do they work better than beta-alumina (for high and low temperatures) ?

Do you think that some of the issues with Sodium (and Potassium) might be resolved when we would use a nano structure (like the
Stanford nanowire design) on the anode ?

Nano-structure would need to be self-replicating, reversible, e.g.
after dissolution / redeposition it needs to be preserved. That is the
main challenge.

Similar problem exists with new innovative cathodes. Indeed many
simple salts
like oxides and flourides are great oxidizing agents with very high
energy densities and
voltages vs Li (see works of Tarascon, for example this one:
http://www.ncbi.nlm.nih.gov/pubmed/16783360?dopt=Abstract
).
But because they are non-conductive, have bad diffusion coefficients
and their crystalline structure is lost during reduction, there are
still not batteries made with them.

If somebody figures a way to make a reversible over many cycles and
electrically counductive nano-structure with these materials, this
will be a hit.
Note that even LiFePO4 initially was considered unsuitable because of
bad conductivity,
but nano-manufacturing and carbonization later solved this problem to
make it a "star" of
todays battery landscape.

Interesting. Thanks for all this info, and the progress/problems of nano structures.
It seems to me however that nano structures address the issue of power density of batteries with existing chemistry (simply because
of their immense large exposed surface area). The Tarascon abstract seems to indicate that too. But what I see much less often is if
nano structures actually enable alternate chemistries (such as using Na instead of Li).

Also, you seem to really like LiFePO4. I know very little about that, other than that they address power density but compromise on
energy density.
Also they still use Lithium. So what is good about it and why do you consider it a star in today's battery landscape ?
I have not seen them in the store yet, not heard much about them for PHEVs and EVs...

..........

I looked at several out-of-the-box ideas for a super battery : Here is one theoretical one : Sodium Fluoride electro
chemical
cells.
Theoretical energy density of 3690 Wh/kg.
Many engineering issues remain.. One big issue : We need to find a way to store Fluorine gas. This might be similar to the
problem
of storing hydrogen gas in hydrogen powered vehicles. Interesting overlap of engineering >issues huh ?

Actually F2 is not that difficult to store. It passivates aluminum,
for example, and you can keep it in Teflon.

But in addition to its aggressiveness, it is the most poisonous
compounds known to man.
I doubt that anybody in clear mind would suggest putting it into cars.

It was a theoretical example. To continue the 'gedanken experiment', if we could find a cathode design with an immense surface
area,
we may be able to store Fluorine gas in the atomic nooks and cracks. Maybe it would stay there even at atmospheric pressure, so
that
it won't escape even if the battery gets crushed... Engineering challenge only...
If that is still considered unsafe, maybe we can store Cl2 gas, which is a lot less toxic. The NaCl system yields 1913 Wh/kg
theoretical. Enough for most people...

I think Tarascon approach converges with your idea to somehow
encapsulate F2.
You will lose some energy in the binding energy of encapsulation.
So you could just as well use Flourides and oxides, that already have
very high oxidative
potential and will give high voltage vs Li.

That makes sense : the energy density goes down because we need a lot of encapsulation material.

But what would the chemistry look like for such a cell using fluorides and oxides as you suggest ?
And wouldn't the electrode potential be determined by the (metal) oxides and no longer by the fluorides themselves ?
I looked at some fluoride-based chemistries using but ended up with rather low energy densities OR (if molten salt form) with very
high melting temps.
Maybe I'm not looking at this the right way.... OK. Here is my question : How can fluorides or oxides have high oxidative potential
by themselves ?

Regards,
Yevgen

Thanks for your responses Yevgen. It is a pleasure talking with somebody who really knows what they are talking about.
Seems to become a rare occurrence these days on the NGs.

One question : I am a big fan of the Zebra (NiNaCl) cells for PHEVs and EVs.
If you were to improve the current (especially energy density) performance and/or lowering the operating temperature, what would you
do differently in the cell design ?

Also, there is only one company (MES-DEA in Switzerland) that makes this type of batteries. Do you know why noone else makes them ?
The patents on NiNaCl and other molten-salt chemistries are from the 70's and should be free to use now.
Can anyone start making Zebra cells now ?

Rob

Regards,
Yevgen

Rob