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Power Science

Memory Effect Discovered In Lithium-Ion Batteries 157

Posted by samzenpus
from the a-little-less dept.
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."
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Memory Effect Discovered In Lithium-Ion Batteries

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  • No Shit (Score:2, Insightful)

    by Anonymous Coward on Monday April 15, 2013 @01:48PM (#43453727)

    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.

  • by geoskd (321194) on Monday April 15, 2013 @01:52PM (#43453753)

    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?

    -=Geoskd

  • by jeffmeden (135043) on Monday April 15, 2013 @01:58PM (#43453821) Homepage Journal

    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?

    -=Geoskd

    According to what I could read of TFA without paying $32, the memory effect is actually seen just during discharge, as a function of distorting the voltage vs w/hr capacity. The overall w/hr capacity of the battery is not reduced, but the ability to exactly determine SOC is diminished at mid voltage levels.

    I am not a chemist, so input from someone with more insight on the exact study would be appreciated.

  • by BitZtream (692029) on Monday April 15, 2013 @04:55PM (#43455727)

    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.

  • by swalve (1980968) on Monday April 15, 2013 @09:34PM (#43457685)
    The only way to know the state of charge is by measuring voltage. Sometimes, batteries fail in that they never manage to get to their "charged up" voltage. Other times, they fail where they appear to top off instantly, and since the voltage is correct, the battery utilities think it is charged. The only way to actually test a battery is to put a known load on it and see how long it takes to hit a certain voltage.

    What you experienced was not memory effect, but one or more of the cells failing. Some of them probably would never charge completely up, and the other cells got pushed into over voltage to compensate. If you have cells in series, this is pretty much going to happen sometimes.

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