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.
lithium battery ignition
Started by ●October 14, 2023
Reply by ●October 14, 20232023-10-14
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.
Reply by ●October 14, 20232023-10-14
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: >> 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.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.
Reply by ●October 15, 20232023-10-15
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. -- Bill Sloman, Sydney
Reply by ●October 15, 20232023-10-15
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.
Reply by ●October 15, 20232023-10-15
On Sunday, October 15, 2023 at 4:18:13 PM UTC+11, Eddy Lee 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:<snip>> > > 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.You wouldn't do well in the pyrotechnics industry.> > 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.If you overcharge them enough to develop lithium metal bridges inside the battery, leading to high self-discharge and cell heating, you can produce a problem. Modern battery management systems are designed to minimise that risk, but you seem to bypass them.> > > 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.Flyguy is equally convinced of the same proposition. If he had the skills to get a Ph.D. he might also have the sense to realise that you (or a couple of properly programmed integrated circuits) can manage lithium cells in a way that makes them much less likely to ignite. -- Bill Sloman, Sydney
Reply by ●October 15, 20232023-10-15
On 15/10/2023 3:03 am, John Larkin wrote:> 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:<snip>> 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.There are a whole lot of utility scale grid storage batteries that have lasted for years, so it isn't all that difficult.> 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.It's a great concept, but it hasn't been attractive enough to get anybody to manufacture them in mass market quantities at mass market prices. Tesla has eaten their lunch. -- Bill Sloman, Sydney
Reply by ●October 15, 20232023-10-15
On Sat, 14 Oct 2023 22:18:09 -0700 (PDT), Eddy Lee <eddy711lee@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: >> > 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.We need commom sense, which universities don't award.
Reply by ●October 16, 20232023-10-16
On Sunday, October 15, 2023 at 7:16:11 AM UTC-7, John Larkin wrote:> 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.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.
Reply by ●October 16, 20232023-10-16
On Monday, October 16, 2023 at 1:16:11 AM UTC+11, John Larkin wrote:> 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:<snip>> >We don't need a PHD to know that Lithium cells can ignite. > > We need common sense, which universities don't award.John Larkin seems to define common sense as the facility to make the same mistakes as John Larkin. He thinks that Donald Trump has it. Universities seem to think that anybody bright enough to get admitted as an undergraduate has it - but Tulane admitted John Larkin - so they don't have to each it. -- Bill Sloman, Sydney
