As @Axeman said, this battery could be used in other phones (of LG) as well. I don't think this question is related to Android. My guess is it's for NFC, my Galaxy Nexus has 4-pins and all 4-pins exist in both battery and phone.
If your LG phone has 4 pin battery port, it's got this "DRM". If not, it simply doesn't care. Nice answer - irrespective of whether I can verify it or not. The extra connections on the battery are for an NTC thermistor within the battery so the phone can monitor the battery temp.
And this way, the BTEMP pin helps the processor in controlling the status and charging current of the battery. Thus ensuring a longer battery life of mobile phones. So with that being said, now whenever you will see a battery with 4 terminals you exactly know why it has more than two terminals:
The third pin is usually found on Li-Poly, or Lithium Polymer batteries and is required in order to charge the battery safely. Because these batteries are usually multi-cell, the third pin is used for balancing the charge between each of the cells.
Lots of new batteries (for mobile devices, MP3 players, etc) have connectors with 3 pins. I would like to know what is the purpose of this and how should I use these three pins? They are usually marked as (+) plus, (-) minus, and T. Where have you seen the third pin? Im interested in it. Roomba batteries too.
Most consumer devices that have lithium single-cell batteries have 4 connections. I've noticed the following diverse types of devices, this is true: The 4-connection rule seems to hold even with devices that have multi-cell batteries like cordless drills.
Some of them are thermistors, others are ID pins for identifying the type of battery (based on resistance), or I2C (pair of pins), and still others are 1-wire comms. My Samsung battery, for example, is 4-terminal, with 3 of the terminals labeled -, …