Qualcomm has announced Quick Charge 3.0, the latest iteration of their fast battery charging technology. The new version is said to not only further improve battery charging times, but also better maintain battery health and reduce temperatures.
One of the biggest issues with fast battery charging is the premature failure of the battery cells; something my first Nexus 6 (which was replaced due to a bad battery) can attest to. The new 3.0 standard adds "Battery Saver Technology" (BST) which constantly varies the current delivery rate based on what the battery can safely accept, thus preventing damage to the cells. This new version of Quick Charge also claims to offer lower temps while charging, which could be partly the result of this variable current delivery.
The other change comes from "Intelligent Negotiation for Optimum Voltage" (INOV), which can vary the voltage delivery anywhere from 3.6V to 20V in 200mV increments depending on the device's negotiated connection. INOV will allow Quick Charge 3.0 to charge a full 2x faster than the original Quick Charge 1.0 (it's 1.5x faster than QC 2.0), and 4x over standard USB charging as it provides up to 60W to compatible devices.
This new Quick Charge 3.0 technology will be available soon with devices featuring upcoming Qualcomm SoCs such as the Snapdragon 820.