Intermec

Battery Storage

The expected shelf life of a Li-Ion battery is a little difficult to estimate.  It is important to ensure that the battery has a good charge on it though.  Like any other battery technology, Li-Ion batteries will self-discharge over time, even when not in use.  It is a slow process, but it does occur.  The is one reason that we ship our batteries with a partial charge.  If the battery is allowed to discharge too deeply, it is possible that it will be unable to be recharged.   (This is also something that our smart battery technology prevents during normal usage.)  Its hard to give number on acceptable storage times, but I would try to keep it under a few months or so.

Charging and Life Cycle

The batteries will keep much longer if they have an adequate charge on them.  They don’t necessarily need to be kept in a charger, but keeping some amount of charge on them will allow them to stay “healthy.”

Temperature 

As far as storage environment is concerned, the important thing is to avoid extremes in temperature.  Too high or too low a temperature can adversely affect the life of a battery, even if it isn’t being used.  Storing the batteries within the normal, acceptable operating temperature of the device should be fine.

Operating Lifespan

The normal operating lifespan of one of Li-Ion batteries is another one of those things that is difficult to estimate.  Over its useful life, the battery is going to develop an increased impedance and the average run time will gradually diminish.  It will not develop a “memory” as such, like other battery technologies are prone to do.  Also, unlike those other technologies, it is not a good practice to allow the battery to fully discharge periodically. 

Discharge Cycles

It is useful to think of the lifespan of a Li-Ion battery in terms of full discharge cycles.  If the battery is allowed to discharge completely, that is a full discharge cycle.  If the battery is allowed to discharge 50%, that is half of a discharge cycle, 25% is a fourth, etc.  Charging the battery more frequently does not harm it and, in fact, can actually lengthen its useful life.  In general, a Li-Ion battery should have about 500 full discharge cycles in it.  My rule of thumb estimate of one of our batteries lifespans is about 12 to 18 months, depending on usage patterns.

Author: Intermec

Publication Date: 9/29/2011