- Sep 30, 2017 -
Now mobile phone charger with lithium ion battery, speaking of the lithium ion battery, first to simple introduce, the so-called lithium ion battery is used to hide, out of the carbon material as a cathode active material of lithium ion batteries, lithium ion symbols for Li - ion. Batteries are generally composed of positive, negative, diaphragm, electrolyte and other basic elements.
Lithium ion battery charging process is divided into two steps: first the constant current charging, the constant current, constant voltage, when charged to 4.2 V voltage automatically converted to constant voltage charging, constant at constant voltage charging voltage, electric current is smaller and smaller until the charging current is less than preset values, so someone with direct charge of mobile phone battery recharged when power shows obviously already full, but still show is charging, in fact, this time has reached 4.2 V voltage so power displayed as full, then is in constant voltage charging process.
Then someone may ask, why to be constant voltage charging, with constant current charge directly to the 4.2 V are not to go, actually very easy to explain, because every cell has certain internal resistance, when using constant current charging to 4.2 V, the 4.2 V battery is not the actual voltage, but the consumption on the battery voltage with battery internal resistance of the sum of the voltage, if current large consumption on internal impedance voltage is very big, so it is the actual battery voltage may be smaller than 4.2 V, so use constant-voltage charging process, will slowly drop after you get the charging current, such actual voltage of the battery is very close to 4.2 V.
Mobile phone charging, the charger will first 220 v alternating current (ac) through the rectifier circuit into high voltage direct current (dc), and then through the switch tube into a high frequency high voltage pulse, and then through the transformer into a low pressure pulse, low pressure numerical depends on the specific voltage by charging equipment needs. At last, the low pressure pulse passes through the rectifier and the stable voltage circuit becomes the corresponding direct current. That is to say, the process from 220V ac to 5V direct current will mainly go through the rectifier circuit, transformer, voltage stabilizer circuit and so on. The charger only changes the form of electric energy.