newvlithium ion battery, page-4

Good pick ups guys. In reading about lithium-ion batteries this week it was sobering to see how much more complex they have to be in order to control the discharging process and to keep them cool. However, the weight reduction and discharge profile give them so many advantages.
Theis is from Australian Wood Review regarding li-ion power tools and may be of interest.

"Li-ion batteries are superior because of their high energy to weight ratio and resistance to memory effect. . . lithium is the third lightest element, much lighter than cadmium. A weight reduction can be made of around 50% for the same voltage . . . an 18V li-ion battery weighs around the same as a 12V ni-cad . . . Being resistant to the memory effect these batteries can be charged whenever you like unlike other batteries which can be ruined if topped up when not fully discharged. Li-ion batteries are far more immune to self-discharge than the older style batteries. This means a charged battery can be left on the shelf for months and can contain up to all of its original charge.
Li-ion batteries do require care as they are subject to damage, particularly from heat. Don't store the batteries in hot places as potentially they can rupture at extreme temperatures. If a battery is hot from heavy work it will take longer to recharge. The battery pack must cool before it can be charged. . . Li-ion batteries cannot handle being discharged below a certain voltage so extra circuits are built in to shut the battery down to avoid permanent damage . . . Disadvantages of li-ion batteries are that the cells require sophisticated electronic protection to avoid damage from overcharging, overloading and heat. . . Ni-cad batteries will run down slowly then come to a halt. A li-ion will give its all right up to full discharge then stop. . ."

I suspect that all the R & D going on in this direction is going to smooth out some of the negatives. The future is lithium.