What is fast charge?

Recently to see such a question: "From 2014 onwards, fast charging technology after another, the most representative of the technology Qualcomm Quick Charge2.0, MediaTek's Pump Express, there OPPO VOOC, representative models have millet note , Meizu MX5, OPPO Find7. What are the above characteristics of these technologies, and also among the early years of rumors, high-current fast charge will cause the battery overheating, damage battery life, then the fast charge technology will affect the battery life?

Now the rapid development of mobile phone technology, in addition to the hardware itself is constantly updated mobile phone, charging this step is also increasingly subject to the developer's attention, as mentioned in the above question, fast charge technology from 2014 began to unveil the market , The major mobile phone brands have to fast charge as a major highlight of publicity.

Fast charge in short is fast charging, generally can reduce the charging time by half or more, but currently can only be used in the field of mobile phones.

First of all, briefly describe the three stages of mobile phone lithium battery charging, namely: constant current pre-charge, high current constant current charging and constant voltage charging. The standard for three-stage conversion is the battery voltage.

Constant current precharge can be seen as a protective measure, in order to allow over-discharge of the lithium battery slowly restored for the next stage to do a large current charge buffer. When the battery voltage is higher than 3.0V when it entered a large current constant current charge, the appropriate increase in the charge current, different battery current size from 0.1C to several C floating.

This stage, the state recommended standard is 0.1C current charge (C is the battery capacity), the benefits of the standard charge is naturally safe and stable. But the drawback is that for too long, as in the past, mobile phone charging usually takes five or six hours or seven or eight hours. The fast charge is at this stage with more than 0.1C of current.

General fast charge current is 0.2C ~ 0.8C, in fact this figure is not high for today's technology, so fast charge or safe. When the voltage rises to 4.2V when the charge to enter the final stage - constant voltage charging, when the voltage is constant, the current is getting smaller and smaller until full.