Special precautions must be taken to avoid Li-Ion battery fire up

Did you recently notice poor performance of your notebook Li-Ion battery?. Don't be taken aback, this is happening even to the best battery! Now days Li-Ion batteries are widely used in portable devices due to there excellent energy to weight ratio and for the reason they are not suffering from "memory effect".

These two reasons make them the best choice on portable devices, but not suffering from "memory effect" doesn't mean it will last for ever!HP 338794-001 Battery Chemical conversions inside the battery make it to produce electric energy but these chemical reactions aim to attenuate as time and charge cycles pass over.

When the battery life drops significantly it's time to search for a replacement, HP F4486A Battery, HP CGR-B1870AE Battery, HP Pavilion ZD7000 Battery, HP PP2182D Battery,but you will recently find out that most of notebook batteries cost almost 1/3 to 1/2 the price of the laptop at the time you will need to replace the battery. So if you want to keep your laptop but don't want to spend much money for battery replacement it's time to think about rebuild it your own, replacing each individual cell inside the pack.

But before step on this you must consider many parameters messing around Li-Ion batteries, about the way they are charged and the way you must handle them.


Special precautions must be taken to avoid Li-Ion battery fire up or explosion that can cause serious injuries. This is because Lithium when comes in contact with water or air's moisture burns violently. Never try to extinguish such a fire with water! but only with suitable extinguisher.

In this article we will discuss how to handle Li-Ion batteries to avoid any malfunction, the precautions you must take, the way Li-Ion batteries are charged, the protection circuits used and finally you can find a step by step guide on how to reconstruct a Fujitsu - Siemens Lifebook S-Series FPCBP25 battery pack. This guide can also be read as a tutorial on how to rebuild other kind of Li-Ion battery packs except the one we will use here.

It's recommended to read the following details in order to understand how a Li-Ion battery must be handled to avoid any injury,HP PP2182D Battery before proceed to the reconstruction of the pack.

Overview

Li-Ion (and Li-Po) batteries are leading edge battery technology and consists ideal selection in use on portable computers and cellular phones due to their high energy density and high voltage. A typical Li-Ion cell is rated at 3,6V and this is three times more than the typical NiCd or NiMH cell voltage (1,2V).

Structure
Li-Ion cell has a tree layer structure. A positive electrode plate (made with Lithium Cobalt oxide - cathode), HP F4486A Battery, HP CGR-B1870AE Battery, HP Pavilion ZD7000 Battery, HP PP2182D Battery, a negative electrode plate (made with specialty carbon - anode) and a separator layer.

Inside the battery also exists a electrolyte which is a lithium salt in an organic solvent.

Li-Ion is also equipped with a variety of safety measures and protective electronics and/or fuses to prevent reverse polarity, over voltage and over heating and also have a pressure release valve and a safety vent to prevent battery from burst.

Never short circuit, reverse polarity, disassemble, damage or heat over 100 degrees Celsius a Li-Ion cell. That can be really dangerous.

Working Principle

Lithium battery uses lithium cobalt oxide as positive electrode - cathode - and a high crystallized special carbon as negative electrode - anode.

Also an organic solvent specialized to be used with the specific carbon works like electrolytic fluid.

The chemical reaction that takes place inside the battery is as follows, HP Pavilion ZD7000 Battery during charge and discharge operation:

The main principle behind the chemical reaction is one where lithium in positive electrode material is ionized during charge and moves from layer to layer in the negative electrode (as illustrated to the left image).

During discharge Li ions move to the positive electrode where embodies the original compound.

Features of lithium Ion batteries

High energy density that reaches 400 Wh/L (volumetric energy density) or 160Wh/Kg (mass energy density).
High voltage. Nominal voltage of 3,6V or even 3,7V on newer Li-Ion batteries.
No memory effect. Can be charged any time, but they are not as durable as NiMH and NiCd batteries.
High charge currents (0,5-1A) that lead to small charging times (around 2-4 hours).
Flat discharge voltage allowing the device to stable power throughout the discharge period.
Typical charging Voltage 4,2 ± 0,05V.
Charging method: constant current - constant voltage (CV-CC).
Typical operation voltage 2,8V to 4,2V
Recommended temperature range 0-40

Charging Characteristics

Charging method is constant current - constant voltage (CV-CC). This means charging with constant current until the 4.2V are reached by the cell (or 4,2V x the number of cells connected in series) and continuing with constant voltage until the current drops to zero. HP F4486A Battery, The charge time depends on the charge level of the battery and varies from 2-4 hours for full charge. Also Li-Ion cannot fast charge as this will increase their temperature above limits. HP F4486A Battery, HP CGR-B1870AE Battery, HP Pavilion ZD7000 Battery, HP PP2182D Battery, Charging time increases at lower temperatures.

Typical charging characteristic

Charge current is recommended to be set at 0,7CmA (where C is battery capacity). If voltage is below 2,9V per cell it's recommended to charge at 0,1CmA. Charging environment must have a temperature between 0-40. Maximum discharge current must not exceeds 1.0CmA and discharge voltage must not go below 3,0V