What do the T-pins and D-pins of Sony camera charger mean?

T-pin and D-pin remind the charger to adapt to different charging heads.

The lithium battery has an intelligent safety chip, which records the battery type, production date, charge and discharge times, battery power, etc. The battery displays data, such as power, through the third pin.

Lithium battery is a battery with lithium metal or lithium alloy as negative electrode material and non-aqueous electrolyte solution. Lithium batteries are different from lithium-ion batteries. The former is a primary battery and the latter is a rechargeable battery. Because the chemical characteristics of lithium metal are very active, and the processing, storage and use of lithium metal require very high environment, the application time of lithium battery is not long.