Battery Topic

Recently, SONY, APPLE, DELL, HP, these international famous PC manufacturers, their  notebook batteries appeared problems and recalled factory. Today, I would like to talk about the  topic of extended batteries, to share with everyone.

Why the laptop battery electronic become less and less? Why using battery correction function will let electricity restore partly? What’s the correctly way to charge lithium ion battery? All of this need to be trace from the battery power calculation.

No matter the NI-MH batteries which have been eliminated, nor the lithium ion battery now we are using, for example the dell vostro 1500 replacement li-ion battery, or unusual lithium polymer battery, even future battery star of the silver zinc battery, all of these are equivalent to a storage battery power of warehouse, the difference is that the way of electronic in and out, the volume. In the notebook computer batteries, there is responsible for the management of these batteries electricity housekeeper – it is manager of managing battery, calculated chips, the calculation for the “owner” charge.

In the battery measurement technique, there are four common methods, but not different brand laptop battery use one of the way to calculate electrical, usually several methods are mixed use, one method is the main for calculating, others are auxiliary power calculation.

The first method is open-circuit voltage measurement, this method is by measuring the battery voltage values in the stationary state to calculate the residual capacity, however as the relationship between the lithium ion battery voltage in stationary and the residual capacity belong to nonlinearity, so the method measured values is not accurate, most of cell phone batteries use this calculation method.

The second method is Coulomb Counting, this method is by measuring the battery electric current of charging and discharging, integral the product of the electric current value and time value, then  the result is the electric of charging into power and the power that is released, Coulomb Counting is a comparatively accurate calculation method of electricity.

The third is impedance measurement method, it is through the measurement of the battery cell resistance values obtained the residual capacity.

The fourth is the comprehensive method, by setting up a related table, enter the parameters such as voltage, current, temperature, then get input residual capacity of the battery query.

Therefore, except battery cell, the internal structure of battery include the management of chips, chips contain one or two battery cell power measurement method, and a charge protection circuit. Notebook computer is in the chip system, through the driver interface access chip, then to establish and administer the battery.

However, why will the battery power is less and less, and execute battery correction function can recovery of capacity? Laptop batteries commonly called 6 battery cells, 4 battery cells, it’s the battery within a few battery cells. So many battery cells make up together, it’s the fundamental reason of less power: the different battery cell’s quality, discharge level is impossible completely consistent, such as when discharging, certain battery cell’s electric quality greatly reduced, in order to maintain the voltage stability, battery management according to the principle of “cask theory”,  according to the the worst day for charging protection, so battery power will naturally dropped, or even more than the battery irreversible chemical physics.