Lithium chemistry batteries fall into one of two categories Primary (non-rechargeable) and Secondary (rechargeable). Lithium primary batteries use Lithium as the anode with an electrolyte to release electricity stored in the battery, once this lithium is used the battery no longer gives off any charge and needs to be replaced. Lithium secondary batteries such a Lithium Ion or Polymer use lithium primarily in the cathode. This allows for the Lithium Ion to move between the cathode and anode (charging and discharging) allows these batteries to be used over and over again.
Temperature is the enemy of all batteries. High temperatures cause degradation of the lithium and electrolyte inside the battery and shorten its life-span considerably. Generally, Lithium batteries are formulated made to endure high operating (discharge) temperatures of up to 60°C (Self discharge) and at low temperatures of about -20°C (because of the reduced diffusion rates on the anode). These are not without sacrifices in efficiency, keeping your lithium batteries operating within 25–30°C (77°-86°F) will prolong the life of your lithium batteries.
The discharge rate is the rate a Lithium battery expends all of its charge. This is measure in milliamperes and the discharge is measured in C-rate. For example if battery has a capacity of 2000mAh and has a 1C discharge rate, theoretically it should discharge 2000 milliamperes over 1 hour before exhausted. Any lower C-rate (say at 0.2C) would discharge at 1/5th the rate: 500mA per hour.
Just as C-rates are used for discharge they are also used for charging. The measurement for this also in mill amperes but works slightly different. Say our 2000mAh battery needs a full charge, and our charging rate is 0.5C. This means that our charging rate is 1/2 X 1C (2000mAh) = 1000mA. The C-rate also affects the time, our charge rate 1000mA per hour so it would in fact take 2 hours to reach a full charge to 2000mA.
Self-discharge is the phenomena of the battery releasing a charge, because of the internal chemical reactions, that reduce the stored charge of the battery despite it not being connected to anything to draw that electricity. Generally, Nickel based batteries (NiMH) have a self-discharge rate of 10-15% per month, while Lithium rechargeable batteries only about 1-2% per month and an increased shelf-life. Lithium Primary batteries have an incredible shelf-life of self-discharging 10% in 5 years because of its chemistry made for low load currents.
A smart battery is a battery or pack with built-in electronics to manage charging, discharging, fuel gauge, and other important diagnostics to report the state of health of the battery. As batteries get more sophisticated, the management systems to control these batteries will get more complex. Rechargeable Lithium batteries fall into this category because their high energy density. PCMs (Protection Circuit Module) are regularly installed to manage charge, discharge and current rates for the battery packs.