What is the "memory issue" in the following statement "Lithium ion batteries do not have memory issues..."

Question

Lithium ion batteries do not have "memory" issues so you can recharge anytime without first draining the battery

Answer 1

Memory effect, also known as lazy battery effect, is an effect observed in some rechargeable batteries that causes them to hold less charge. In its original meaning it describes one very specific situation in which certain NiCd batteries gradually lose their maximum energy capacity if they are repeatedly recharged after being only partially discharged. Today, the term is commonly applied to almost any case in which a battery appears to hold less charge than was expected, or when a battery is charged when it still has half of its life left several times, the battery will only discharge half the expected amount of power.

Lithium-ion batteries can be formed into a wide variety of shapes and sizes so as to efficiently fill available space in the devices they power.

Li-ion batteries are lighter than other equivalent secondary batteries—often much lighter. The energy is stored in these batteries through the movement of lithium ions. Lithium has the third smallest atomic mass of all the elements giving the battery a substantial saving in weight compared to batteries using much heavier metals. However, the bulk of the electrodes are effectively "housing" for the ions and add weight, and in addition "dead weight" from the electrolyte, current collectors, casing, electronics and conductivity additives reduce the charge per unit mass to little more than that of other rechargeable batteries. A key advantage of using Li-ion chemistry is the high open circuit voltage that can be obtained in comparison to aqueous batteries (such as lead acid, nickel metal hydride and nickel cadmium). [citation needed]

Li-ion batteries do not suffer from the memory effect. They also have a low self-discharge rate of approximately 5% per month, compared with over 30% per month in nickel metal hydride batteries and 10% per month in nickel cadmium batteries.

According to one manufacturer, Li-ion cells (and, accordingly, "dumb" Li-ion batteries) do not have any self-discharge in the usual meaning of this word. What looks like a self-discharge in these batteries is a permanent loss of capacity, described in more detail below. On the other hand, "smart" Li-ion batteries do self-discharge, due to the small constant drain of the built-in voltage monitoring circuit. This drain is the most important source of self-discharge in these batteries.

Answer 2

Daniel is spot on. The electrons change from the positive plate over to the negative plate within old tech batteries - ni cad ( consumer electronics ) and lead acid ( cars ) .When these electrons move thru repeated charge discharge cycles they deterate ( kinda' like you and me getting old ) and get weaker. Well the total discharge and then recharge can be explained this way - I run 6 miles a day every day for 2 years now you ask me to due 26 - i'm only conditioned for 6 and that's what I remember. Lead acid do not have a memory effect - hence the alternator always charging the battery when in use. Never drain a lead acid . Killed your car battery 6 times in a short period of time - you'll be gettin' a new car battery

Answer 3

Older, Nickel Cadmium batteries if charged frequently without fully discharging the batteries first would build a "memory" of the discharge level and would only work to that level, shortening the effective use and life of the battery.

Lithium Ion and newer Polymer batteries have improved this issue.

Answer 4

It dates back to the very first rechargeable Nickel Cadmium batteries. Apparently, if you have a habit of discharging a Ni-Cad battery partially and then charging it up it "remembers" the partial discharge and will only produce useful voltage up to that point instead of being capable of running until completely discharged.

http://en.wikipedia.org/wiki/Memory_effect