We know that heat and Lithium based batteries don't mix but there is more to worry about than catastrophic failure.  A post over at Hack a Day illustrates the consequences of heating a Lithium based battery with 1% or less charge, the complete and permanent death of the batteries ability to hold a charge.  There are some uses for these batteries in designs which can trap heat near to the battery and not properly transfer it out and it is apparently very important to keep those batteries at least moderately charged.  If you are making something which might expose the batteries to excess heat ensure you monitor the charge to prevent having to replace the batteries.  The complete discharge of a Lithium cell is never a good practice and this illustrates another reason to keep those batteries charged.

"There’s a million ways to kill a battery, and lithium batteries are known not to like being completely discharged, but it looks like the combination of deep discharge and heat is entirely deadly. Now you know."

Here is some more Tech News from around the web:

Tech Talk