On Saturday, October 14, 2023 at 11:08:53?AM UTC-4, John Larkin wrote:
There has been conjecture here about lithium battery ignition, thermal
runaway, and whether any measurements could provide useful warning of
a possible cell explosion.
Waiting for my biscuits to cook, a (very) little research turns up not
much about failure dynamics. Most studies measure external cell
temperature as indicators of thermal runaway.
I found one study, from NREL, that used fast radiography to study the
propagation of a reaction front from a local defect.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwi0lbm44PWBAxXRIkQIHWNyAsQQFnoECCoQAQ&url=https%3A%2F%2Fwww.nrel.gov%2Fdocs%2Ffy22osti%2F82410.pdf&usg=AOvVaw3CJ_O8Y-D-J8zDUulMU_mT&opi=89978449
or
https://tinyurl.com/yn9r2rzh
The separators between reactants are usually thin polymers and the
thermal conductivities are low, so I'd expect a small defect to spread
rapidly, somewhere between burning paper and burning gunpowder, I'd
guess.
The NREL radiography shows reaction propagation velocity in the
ballpark of 20 mm/s, so a cell with a small central defect could be
fully engaged in a second or so. Not much time to detect and mitigate
a failure.
This study does conclude that many other gross-measurement studies are
probably unreliable.
Supposedly the solid electrolyte batteries eliminate that hazard. Then there are others using electrode materials that do not combust on contact.
There has been conjecture here about lithium battery ignition, thermal runaway, and whether any measurements could provide useful warning of
a possible cell explosion.
Waiting for my biscuits to cook, a (very) little research turns up not
much about failure dynamics. Most studies measure external cell
temperature as indicators of thermal runaway.
I found one study, from NREL, that used fast radiography to study the propagation of a reaction front from a local defect.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwi0lbm44PWBAxXRIkQIHWNyAsQQFnoECCoQAQ&url=https%3A%2F%2Fwww.nrel.gov%2Fdocs%2Ffy22osti%2F82410.pdf&usg=AOvVaw3CJ_O8Y-D-J8zDUulMU_mT&opi=89978449
or
https://tinyurl.com/yn9r2rzh
The separators between reactants are usually thin polymers and the
thermal conductivities are low, so I'd expect a small defect to spread rapidly, somewhere between burning paper and burning gunpowder, I'd
guess.
The NREL radiography shows reaction propagation velocity in the
ballpark of 20 mm/s, so a cell with a small central defect could be
fully engaged in a second or so. Not much time to detect and mitigate
a failure.
This study does conclude that many other gross-measurement studies are probably unreliable.
There has been conjecture here about lithium battery ignition, thermal runaway, and whether any measurements could provide useful warning of
a possible cell explosion.
Waiting for my biscuits to cook, a (very) little research turns up not
much about failure dynamics. Most studies measure external cell
temperature as indicators of thermal runaway.
I found one study, from NREL, that used fast radiography to study the propagation of a reaction front from a local defect.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwi0lbm44PWBAxXRIkQIHWNyAsQQFnoECCoQAQ&url=https%3A%2F%2Fwww.nrel.gov%2Fdocs%2Ffy22osti%2F82410.pdf&usg=AOvVaw3CJ_O8Y-D-J8zDUulMU_mT&opi=89978449
or
https://tinyurl.com/yn9r2rzh
The separators between reactants are usually thin polymers and the thermal conductivities are low, so I'd expect a small defect to spread rapidly, somewhere between burning paper and burning gunpowder, I'd guess.
The NREL radiography shows reaction propagation velocity in the ballpark of 20 mm/s, so a cell with a small central defect could be fully engaged in a second or so. Not much time to detect and mitigate a failure.
This study does conclude that many other gross-measurement studies are probably unreliable.
On Sunday, October 15, 2023 at 2:08:53 AM UTC+11, John Larkin wrote:
There has been conjecture here about lithium battery ignition, thermal runaway, and whether any measurements could provide useful warning of
a possible cell explosion.
Waiting for my biscuits to cook, a (very) little research turns up not much about failure dynamics. Most studies measure external cell temperature as indicators of thermal runaway.
I found one study, from NREL, that used fast radiography to study the propagation of a reaction front from a local defect.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwi0lbm44PWBAxXRIkQIHWNyAsQQFnoECCoQAQ&url=https%3A%2F%2Fwww.nrel.gov%2Fdocs%2Ffy22osti%2F82410.pdf&usg=AOvVaw3CJ_O8Y-D-J8zDUulMU_mT&opi=89978449
or
https://tinyurl.com/yn9r2rzh
The separators between reactants are usually thin polymers and the thermal conductivities are low, so I'd expect a small defect to spread rapidly, somewhere between burning paper and burning gunpowder, I'd guess.
But what's going to produce that "small defect"? If it was there at manufacture the battery would burn up when it was first charged.
The NREL radiography shows reaction propagation velocity in the ballpark of 20 mm/s, so a cell with a small central defect could be fully engaged in a second or so. Not much time to detect and mitigate a failure.But such a defect would wreck the battery on first use. A working cell hasn't got such a defect.And they don't seen to develop them all that often - if at all.
This study does conclude that many other gross-measurement studies are probably unreliable.So somebody should fund more of their studies, which they imagine to be more reliable.
On Saturday, October 14, 2023 at 9:59:11 PM UTC-7, Anthony William Sloman wrote:
On Sunday, October 15, 2023 at 2:08:53 AM UTC+11, John Larkin wrote:
The separators between reactants are usually thin polymers and the thermal conductivities are low, so I'd expect a small defect to spread rapidly, somewhere between burning paper and burning gunpowder, I'd guess.
Ejecting over 50% of the mass in couple of minutes would qualify as firework/rocket, in my humble opinion.
But what's going to produce that "small defect"? If it was there at manufacture the battery would burn up when it was first charged.
The NREL radiography shows reaction propagation velocity in the ballpark of 20 mm/s, so a cell with a small central defect could be fully engaged in a second or so. Not much time to detect and mitigate a failure.But such a defect would wreck the battery on first use. A working cell hasn't got such a defect.And they don't seen to develop them all that often - if at all.
Not necessary, I have many cells going bad after several charge/discharge cycles. They would get hot enough to be problematic, if not with the fuse for disconnection.
This study does conclude that many other gross-measurement studies are probably unreliable.
So somebody should fund more of their studies, which they imagine to be more reliable.
We don't need a Ph.D, to know that Lithium cells can ignite.
On Sat, 14 Oct 2023 08:20:22 -0700 (PDT), Fred Bloggs <bloggs.fredbloggs.fred@gmail.com> wrote:
On Saturday, October 14, 2023 at 11:08:53?AM UTC-4, John Larkin wrote:
If there are enough joules stored in the reactants of a battery to pump it up 1000c or so, it's going to be hard to keep them apart.
Liquid flow batteries are a great concept. Most of the energy is
stored as two separated tanks and only a little has to get close and
react.
On Saturday, October 14, 2023 at 9:59:11?PM UTC-7, Anthony William Sloman wrote:
On Sunday, October 15, 2023 at 2:08:53?AM UTC+11, John Larkin wrote:
There has been conjecture here about lithium battery ignition, thermal
runaway, and whether any measurements could provide useful warning of
a possible cell explosion.
Waiting for my biscuits to cook, a (very) little research turns up not
much about failure dynamics. Most studies measure external cell
temperature as indicators of thermal runaway.
I found one study, from NREL, that used fast radiography to study the
propagation of a reaction front from a local defect.
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwi0lbm44PWBAxXRIkQIHWNyAsQQFnoECCoQAQ&url=https%3A%2F%2Fwww.nrel.gov%2Fdocs%2Ffy22osti%2F82410.pdf&usg=AOvVaw3CJ_O8Y-D-J8zDUulMU_mT&opi=89978449
or
https://tinyurl.com/yn9r2rzh
The separators between reactants are usually thin polymers and the thermal conductivities are low, so I'd expect a small defect to spread rapidly, somewhere between burning paper and burning gunpowder, I'd guess.
Ejecting over 50% of the mass in couple of minutes would qualify as firework/rocket, in my humble opinion.
But what's going to produce that "small defect"? If it was there at manufacture the battery would burn up when it was first charged.
The NREL radiography shows reaction propagation velocity in the ballpark of 20 mm/s, so a cell with a small central defect could be fully engaged in a second or so. Not much time to detect and mitigate a failure.But such a defect would wreck the battery on first use. A working cell hasn't got such a defect.And they don't seen to develop them all that often - if at all.
Not necessary, I have many cells going bad after several charge/discharge cycles. They would get hot enough to be problematic, if not with the fuse for disconnection.
This study does conclude that many other gross-measurement studies are probably unreliable.So somebody should fund more of their studies, which they imagine to be more reliable.
We don't need a PHD to know that Lithium cells can ignite.
On Sat, 14 Oct 2023 22:18:09 -0700 (PDT), Eddy Lee
<eddy7...@gmail.com> wrote:
We don't need a PHD to know that Lithium cells can ignite.We need commom sense, which universities don't award.
On Sat, 14 Oct 2023 22:18:09 -0700 (PDT), Eddy Lee <eddy7...@gmail.com> wrote:
On Saturday, October 14, 2023 at 9:59:11?PM UTC-7, Anthony William Sloman wrote:
On Sunday, October 15, 2023 at 2:08:53?AM UTC+11, John Larkin wrote:
We don't need a PHD to know that Lithium cells can ignite.
We need common sense, which universities don't award.
John Larkin wrote:
We don't need a PHD to know that Lithium cells can ignite.We need commom sense, which universities don't award.
Of course not; universities are few, and common sense is... by
definition, mass-produced already.
So, there's no need, no market, for such an offering.
We also need oxygen in our atmosphere; universities don't award
that, either, for the same reason.
whit3rd wrote:
John Larkin wrote:** ROTFL !! How completely asinine.
We don't need a PHD to know that Lithium cells can ignite.We need commom sense, which universities don't award.
Of course not; universities are few, and common sense is... by
definition, mass-produced already.
So, there's no need, no market, for such an offering.
FYI imbecile: so called "common sense" is in reality far from common, cannot be taught by authoritarian institutions and is only learned by some from experience.
On Sun, 15 Oct 2023 23:06:52 -0700 (PDT), Phil Allison
<palli...@gmail.com> wrote:
whit3rd wrote:
John Larkin wrote:** ROTFL !! How completely asinine.
We don't need a PHD to know that Lithium cells can ignite.We need commom sense, which universities don't award.
Of course not; universities are few, and common sense is... by
definition, mass-produced already.
So, there's no need, no market, for such an offering.
FYI imbecile: so called "common sense" is in reality far from common, cannot be taught by authoritarian institutions and is only learned by some from experience.
It requires believing (and testing) basic causalities and not being
confused by subtle and infinite complexity.
The "101" level college courses explain the simple causalities, the fundamental principles. In some areas, like physics, the graduate-level studies respect and fine-tune those basics.
In some areas, like economics and psychology and sociology and journalism, the more sophisticated "higher level" studies contradict the basics.
Common sense mostly requires the willingness to say "stop, that doesn't seem right" in the face of sunk costs and peer pressure. Inother words, do what actually works.
On Sun, 15 Oct 2023 23:06:52 -0700 (PDT), Phil Allison
<palli...@gmail.com> wrote:
whit3rd wrote:
John Larkin wrote:
We don't need a PHD to know that Lithium cells can ignite.We need commom sense, which universities don't award.
Of course not; universities are few, and common sense is... by
definition, mass-produced already.
So, there's no need, no market, for such an offering.
Common sense mostly requires the willingness to say "stop, that
doesn't seem right" in the face of sunk costs and peer pressure. In
other words, do what actually works.
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