US 2008/0303528 A1 · Method and Device for Measuring Internal Impedance of Stationary Battery

Abstract

Battery system is widely used in emergent power plant or communication network power plant and its effective management is important. When any one of batteries connected to each other in series is failed during operation of the battery system, since reliability of the system cannot be secured, a problem is arisen to stable operation of the communication network. In a method of separating inferior battery, the battery is operated in floating charge state without separation to generate square current containing charge current and easily generated to flow through the battery cell, voltage signal generated from terminal voltage of the battery by the measuring signal is processed such that only internal impedance voltage signal is separated from harmonics ripple voltage and noise voltage by a synchronized detection calculating algorithm to calculate the internal impedance or effective value thereof (resistance component). When the algorithm is applied after filtering only fundamental frequency and similar component by general filter, measuring precision can be improved and measuring time can be reduced.

Claims17

Dependent claims

A method of measuring an internal impedance of a stationary battery as an object to be measured and an effective value of the internal impedance, the method comprising:

controlling a measuring signal to flow through the object;
the measuring signal is an injection current (Ipw) or a discharge current (Isd) in the shape of a square wave;
filtering a predetermined frequency component necessary for the measurement among frequency components of the measuring signal by a filtering means or by performing a filtering program, the predetermined frequency component being necessary for the measurement of the internal impedance;
filtering an impedance voltage of the predetermined frequency component among an impedance voltage signal of the object to be measured, the impedance voltage signal being generated by the square measuring signal;
and
calculating the internal impedance and the effective value of the internal impedance by using the filtered measuring signal and the filtered impedance voltage signal.

3 more elements

An internal impedance measuring device of a stationary battery for measuring an internal impedance of respective stationary battery cells comprising a large number of stationary batteries or an effective value of the internal impedance, the device comprising:

a current injecting and discharging circuit to make a measuring signal flow through the stationary battery cells of respective strings of stationary batteries, the measuring signal being an injection current (Ipw) or discharge current (Isd) in the shape of a square wave;
current sensing means, installed to respective strings of the stationary batteries, detecting an AC current containing the measuring signal that flows through the respective strings of the stationary batteries;
a switch configured to switch the AC current detected by the current sensing means and an additional current sensing means installed to an output end of the current injecting and discharging circuit to a measuring and calculating circuit;
a current connecting means to switch the measuring current to the respective strings of the stationary batteries;
and the measuring and calculating circuit to calculate the internal impedance or the effective value of the internal impedance using the measuring signal and a measuring frequency component of an impedance voltage signal of the battery cells.

2 more elements

Dependencies are inferred from the claim text.

Method and Device for Measuring Internal Impedance of Stationary Battery

Life of this patent

Method and Device for Measuring Internal Impedance of Stationary Battery

Life of this patent

Abstract

Claims17