I've seen this pop up in the news a couple of times. It looks interesting:
http://powerelectronics.com/batteries/ne...3cb404689356b15
http://powerelectronics.com/batteries/ne...3cb404689356b15
interesting development for lithium batteries
- Thread starter Rick in PA
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Cool, now my high tech flashlight will shut down when I need it most, COOL!
Thats why I run lithium primaries in critical applications like my structural helmet light and my weapon light.
Originally Posted By: JerryBob
Somewhat related, I notice that my Li-Ion cordless drill dies suddenly, as opposed to the slow decline of the NiCd batteries.
I miss the warning sign of the older batteries.
If you were to discharge a LiIon battery to the point of a NiCd or NiMH, you'd get a pretty stern warning... it'd probably catch fire.
LiIon lives life in a very specific voltage range. Too high causes problems and too low causes problems... bot are usually in the form of thermal events. LiIon batteries have a very steady discharge rate. That is, as they discharge, voltage remains pretty steady and there is little performance change while it discharges through use... until it reaches the "cliff".
Once the battery reaches a certain discharge point, it will very rapidly lose voltage. This is bad both for the life of the battery and the safety of the user. It's actually the battery controller logic (most consumer applications have smarts in the battery or device) that causes the abrupt shut off in LiIon batteries. The logic in the controller monitors discharge rates and voltage. When it see the approaching cliff, it simply turns the battery off. That results in a very abrupt stoppage, but it's completely normal.
Of course, there are cheap devices that use substandard batteries and/or controllers (or no controller at all!)... I'm talking about hoverboards... that have a trend of setting themselves on fire.
The same goes for charging. Good chargers will actually measure voltage and voltage rise in each cell and "balance" them while they're charging, charging only a specific cell if it is lower than another. The idea is that each cell is charged to the same value and when it is discharged, each cell is discharged to the same level, with no one getting over or under-discharged.
The idea proposed in the article is that when a battery is over-charged or over-discharged (or charged/discharged too hard), the battery would protect itself through chemistry, without needing controller intervention, possibly allowing safe use without smarts to control the battery.
Somewhat related, I notice that my Li-Ion cordless drill dies suddenly, as opposed to the slow decline of the NiCd batteries.
I miss the warning sign of the older batteries.
If you were to discharge a LiIon battery to the point of a NiCd or NiMH, you'd get a pretty stern warning... it'd probably catch fire.
LiIon lives life in a very specific voltage range. Too high causes problems and too low causes problems... bot are usually in the form of thermal events. LiIon batteries have a very steady discharge rate. That is, as they discharge, voltage remains pretty steady and there is little performance change while it discharges through use... until it reaches the "cliff".
Once the battery reaches a certain discharge point, it will very rapidly lose voltage. This is bad both for the life of the battery and the safety of the user. It's actually the battery controller logic (most consumer applications have smarts in the battery or device) that causes the abrupt shut off in LiIon batteries. The logic in the controller monitors discharge rates and voltage. When it see the approaching cliff, it simply turns the battery off. That results in a very abrupt stoppage, but it's completely normal.
Of course, there are cheap devices that use substandard batteries and/or controllers (or no controller at all!)... I'm talking about hoverboards... that have a trend of setting themselves on fire.
The same goes for charging. Good chargers will actually measure voltage and voltage rise in each cell and "balance" them while they're charging, charging only a specific cell if it is lower than another. The idea is that each cell is charged to the same value and when it is discharged, each cell is discharged to the same level, with no one getting over or under-discharged.
The idea proposed in the article is that when a battery is over-charged or over-discharged (or charged/discharged too hard), the battery would protect itself through chemistry, without needing controller intervention, possibly allowing safe use without smarts to control the battery.
Great invention for electrified tinfoil hats. Might prevent the user from getting hurt....oh wait...not so great invention.
JHZR2
Staff member
Another play on the shutdown separator. Perhaps the folks in a power electronics website should be considering the effects of controls, ripple, and other switching related behaviors that are causative to the failures often encountered...
There's always those who prefer a goof button to actually fixing the problem.
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