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The Overcharge And Over Discharge Of Lithium Battery Flashlight

The Overcharge And Over Discharge Of Lithium Battery Flashlight

2016-02-17

Usually the lithium polymer battery (Li-ion) of the electrical core cathode using LiCoO2, LiNiO2, LiMn2O2, where LiCoO2 is a layer structure is very stable polymorph, but when taking XLi from LiCoO2, and its structure may change,but not change depending on the size of the X.

Through the study found that the structure performance when X>0.5 Li1-XCoO2 is extremely unstable, will crystal collapsed, its external manifestation ofoverwhelming end for electric core. So the electric core should be controlled in Li1-XCoO2 X by limiting the charging voltage in the use process, the generalcharging voltage is not more than 4.2V, then X is less than 0.5, then the crystal type of Li1-XCoO2 remains stable.

Overcharge and over discharge, the positive and the negative pole of lithium ion battery causing permanent damage, from the molecular level, can intuitively understand. Excessive discharge will lead to excessive release ofcarbon anode of lithium ion and the lamellar structure collapse, the lithium iontoo many hard into the carbon anode structure to over charge, and makessome lithium ion cannot release. The control circuit is one of the reasons whyare usually equipped with a lithium ion battery charging and discharging.

The negative C6 itself has its own characteristics, when the first polarized into,positive LiCoO2 Li was in charge of the negative C6, when the discharge when Li returned to positive in LiCoO2, but after the formation must be part of a Li at the cathode in C6, in order to ensure the normal embedded in the nextcharging and discharging Li, otherwise the electric core over very short, in order to ensure there is a part of Li at the anode C6, generally by limiting thedischarge lower limit voltage to achieve. So the lithium core security chargeupper limit voltage ≤ 4.2V, discharge lower limit voltage greater than 2.5V.

Of course, if it is forced discharge, in 0V, the problem is Li is a high activeelements, overcharge and over discharge will bring risk. Finished the flashlight battery now normally used only in 3V, it is because the lithium batteryprotection board, a protective plate set discharge voltage is about 3V, and then put will protect, forced off the discharge. Is set to 3V because the battery to the 3V is basically the amount of discharge of all, continue to use will make the voltage decline very rapidly. Now manufacturers of industrial lithium is generally recommended minimum discharge voltage of less than 2.25V. Belowthis value will cause permanent damage of lithium battery, the battery swelleffect.