Internal heat is just as bad. When the processor is severely loaded it emits more heat that is bad for the longevity of the unit. To avoid this remove the battery(strictly when it's off) and use the computer on AC power if you expect it to run processor or GPU heavy applications.
And do not freeze the battery, this can be just as destructive. If you think you may want to buy a spare Li-ion battery to have on hand as a back up, don't bother. They have a shelf life so if you do not use it before it ends you have wasted your money. Also check the manufacturing date on a battery you may be buying to be sure the lithium ion batterty stocks expiration is not approaching.
The lithium ion batterty stocks practical EV like the RAV or the Solectria Force. These rigs were designed to get the job done. Many homemade conversions fit into this class as well.
Most of the laptops now a day are equipped with Lithium-ion batteries. Though there are Nickel-cadmium Nickel metal hydride etc after the invention of Lithium-ion battery because of its efficiency most of the laptop cobalt ontario copyright manufacturers are selling it along with their respective laptops.
If you work for long hours on your laptop then the temperature inside the laptop can rise which affects the battery-life. This occurs due to cell oxidation inside the battery and this plays a major factor in reducing the lifespan of the laptop battery.
Keeping your phone or iPod in your pocket may seem like a normal thing to do but your body heat damages lithium-ion batteries. This will shorten battery life. Leave them in your bag or coat to keep them cooler and lasting longer.
In summary, a laptop battery is so costly and its life so precious that we cannot ignore the precautionary measures which makes it possible to extend its lifetime by 2 more years. That means, by following the above said measures, you can use your laptop battery for about 3 years on an average. Good Luck!