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Memory Effect Discovered In Lithium-Ion Batteries
rwise2112 writes "Lithium-ion batteries have long been thought to be free of the memory effects of other rechargeable batteries. However, this appears to be not the case. Scientists at the Paul Scherrer Institute PSI, together with colleagues from the Toyota Research Laboratories in Japan have now discovered that a widely-used type of lithium-ion battery has a memory effect."
shit's paywalled man, no good for Freedom Internets
This has actually been theorized for a long time by people that use Li-On batteries and have to charge them frequently. But they've been told 'nope impossible' by the people who make and research Li-On batteries the whole time. To me this is just like the pharmaceutical industry pushing the next opiate as 'non habit forming' and 'extremely safe' only to have it turn out even more addictive and deadly than the last iteration...time after time.
The question is: how big is the effect. Even a small effect will cause significant distortions in battery metering, but if the effect is large enough, it will cause the batteries not to last any where near as many cycles as originally believed. This could really suck for electric car owners. Any '07 Roadster owners out there care to share how well the batteries are holding up?
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In the source article, I notice it's only about a 4 percent total effect on total charge.
So, while not "no memory effect" it's not as bad as the impacts on the other types of battery storage.
Even storage devices like compressed air (PHES) for wind and solar PV systems have only a 70 percent efficiency, so it's still way better than that.
-- Tigger warning: This post may contain tiggers! --
LiFePO4.
Cliffhangers in the summary now?
I do wish people would stop calling it a 'memory effect'. It's probably the least descriptive term your could apply.
I don't know about Lithium batteries but NiCad cells exhibit a second plateau which gradually gets more difficult for the charge system to punch through. The usual cure is a couple of heavy charge/discharge cycles.
Don't think I want to try that with Lithium though!
I've always wondered why they say that Lithium Ion and Lithium Polymer batteries don't have a memory effect, when even laptop batteries based on those technologies die after several years, and NOT because of charge cycles. I'm talking about the ones that stay plugged in most of their lives, charging. Maybe its the lack of charge cycles that kills them? But to say Lithium batteries have no memory effect has always been ludicrous to me.
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umm, the rabbit was energizer. Still going! nothing outlasts energizer.
It pays to charge your batteries based on your instinct and tradition "just in case" instead of just believing and falling for claims that are only to be proven false later...
Well, I'm set, because I always let my phone nearly die before charging it. That's sure as hell not gonna change now.
nope, it was first introduced by Duracell and then re-used by Energizer, and only in the US at that. In Europe we've only had Duracell's.
According to the first link the issue can be fixed with a software change, and can also be worked around by a full discharge followed by letting the system rest. Doesn't say how long a rest is needed though, depends on the implementation I suspect.
The Duracell Bunny campaign was launched in 1973 and predates the Energizer Bunny, which was created in 1989.
I'd actually love to use LiFePO4 cells for my camping solar setup but the only ones I can find are dodgy Chinese imports with questionable charge controllers.
I can't really vouch for their quality because I am far from a battery expert, but Ping Battery is very highly respected among DIY electric bicycling enthusiasts.
Definitely place them in your category of "dodgy Chinese imports", but anyway they're considered to be very reliable among that particular category!
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Degradation with time and usage != memory effect. Memory effect is a specific kind of degradation due to partial charging or discharging. For example if you recharged a NiCd battery that was only down to 50% charge you would immediately and permanently reduce it's total capacity, hence the tendency of those "in the know" to drain the batteries completely before recharging them.
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I need science to figure out why my significant other has these 'memory issues' -- I'd like to win at least one discussion in my life...
First of all of LiFePO4 are not commonly used in any of our portable gadgets.
Second memory effects we are seeing in our gear are illusions based on memory effects in the electronics that help figure out capacity. Deep cycling lion batteries works to clear these effects as what you are actually doing is resetting the "gas gauge" to synchronize with reality of the battery.
In Europe & Australia the term "Duracell Bunny" has entered the vernacular as a term for anything that continues indefatigably while in North America the term "Energizer Bunny" has a similar connotation.
Never heard of the duracell bunny, so I guess it's a US/EU thing. this is one of the biggest dichotomies on slashdot, not apple/google/MS. Speaking of dichotomies, US Customary Units 4evah!
Tell me when there is a problem with cobalt lithium batteries.
There's a difference between the memory effect and the battery wearing out. It is known that a lithium battery will wear out. They even wear out while in storage. Especially when warm and fully charged.
It won't, because they're not using iron cathodes.
And besides that, if you look at the charts, this doesn't cause a loss of capacity, even an apparent loss of capacity. Instead the voltage just reads high during charging. It appears it can foul up capacity remaining estimates, but not actually change the capacity remaining.
http://lkml.org/lkml/2005/8/20/95
And I expect never will. All batteries have various flavors of memory. The only question is, does the memory effect cause enough of a problem to make it worth addressing the issue to extend battery life.
You worry about memory in a NiCad because the process that causes the memory is easily reversible (partially), and the battery itself is still functional.
If the memory effect of Li-Ion only effects ... say 1% of the total capacity before the rest of the chemical processes break down and cause the battery to 'wear out' than it has memory, but from a practical perspective the memory is irrelevant.
There are all sorts of batteries that would appear 'memory less' at first glance, but thats only cause they are so shitty in other ways that you don't get to the point of noticing the processes that cause memory to start happening.
Until a battery is 100% energy efficient, its going to have memory, so never.
Persistent Volume manager for Kubernetes - https://github.com/dwimsey/openshift-pvmanager
Because you're treating your batteries like shit.
Lead Acid batteries (like you car battery) are pretty fucking hard to kill outside of the environment your car subjects them too (heat is a bitch), even that, how many times have you warranty replaced your car battery?
NiCads are relatively resilient. You can certainly hurt them, but you have to do 'known bad' things that every manual and charger label probably has written on it. Don't drop them below 1.2v per cell, keep them cool during charging (heating means you're doing it wrong). I've had high quality packs for my R/C cars last 5 years. First year as 'race' packs, then the next several as warmup/fun packs. You're talking 250-500 charge cycles of extremely harsh use. That is at least 10% of the nicads expected life under what most would consider some of the harshest possible conditions for the batteries to be in. High current discharge while basically laying on an asphalt road way in the Florida sun, to be immediately thrown back on a charger for the next round without letting it cool or anything. Not even needed to memory cycle the batteries, my usage patterns were so harsh they didn't have the time to build up memory before they were shot anyway.
My previous laptop was an amazing example of excellent battery in my eyes. I retired it in the middle of last year, almost exactly 3 years to the day after purchase and it was used from full charge to nearly depleted extensively during that period as my workstation. I admit, towards the end it was getting short, but certainly well past the 80% at 400 cycles. My wifes laptop on the otherhand won't hold a charge for shit and its only 2 years old! Of course, its been sitting with a charge connected to it for its entire life time, which is a horrible thing to do to a Li-Ion.
Persistent Volume manager for Kubernetes - https://github.com/dwimsey/openshift-pvmanager
Tesla uses a different chemistry, so this does not impact them. However, it WILL impact most of the others.
I prefer the "u" in honour as it seems to be missing these days.
'94 Ford Taurus SHO stick, daily driver for about 15 years: I replaced the battery about the middle of every Texas summer- yeah, heat kills, but still, in spite of buying 60+ month batteries. Had a vampirism problem with a faulty alarm that took out two in one year, but other than that, eating batteries was just the price I paid for the enjoyment that car gave me.
Strangely enough, I am using an ACER notebook now that I keep plugged in probably 80% of the time that I use it (and, yes, I know better, I just don't care enough to change). The battery life is down only 20% over when I bought it close to a year ago. I am thinking that the BIOS might be limiting the battery charge to 80% to slow down the destruction of the battery, because I didn't get the expected life out of the battery compared to my previous notebook at the start, but at the one year mark and same usage pattern, this Acer is doing much, much better.
In all the tests I've seen, Duracell has had a few percent advantage over Everready, or any other competitor. They simply make a better product.
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People who keep their laptops on AC are NOT killing their batteries by keeping the system on AC. The batteries are being killed by the fucking design of the laptop's charging circuit! Bonehead charging systems will keep trickle charging the battery even when they shouldn't! The end result is shortened battery life. In effect the laptop was designed to kill the battery prematurely.
Properly designed charging systems do not do this. If you bought a cheap-ass laptop you can expect it to chew up batteries. The only way to avoid that is if you manage the charge cycle yourself.
Funny... I have a 2001 Apple Ti-book... It is on its second battery pack(the first one was killed by keeping the system in storage for over a year without any charge). I have never taken any special precautions for the battery, other than to make sure it gets FULLY recharged ASAP after a discharge cycle. It spends many months at a time in sleep mode, and is only off AC a few times a year. The battery in it now was purchased new over 7 years ago... It still holds 4 - 5 hours of capacity under conservative loads. This is about 20% less than what it did new.
The reason this is so, is that:
1. The charging system was designed not to abuse the battery in any way.
2. The battery is mounted in a location in the chassis that is not subject to heating from other system components.
Conclusion after 12 years of use? The battery chemistry is not the problem. PEBCAK, and shitty engineering kills batteries.