Hioki 3550 - Page 23

3550 Battery HiTESTER Series
23
To Evaluate the Performance of Secondary Batteries Using Low
Resistance Measurement Techniques
Hiroshi Kutsukake - Kenji Kobayashi - Mitsuyoshi Tanaka
HIOKI E.E.CORPORATION
Abstract
As portable communications terminals for individuals (typified by devices such as cellular
telephones and notebook computers), uninterruptible power supplies (UPSs), and other types of
equipment that use secondary batteries become widespread, there is a growing need to be able
to easily evaluate the performance of secondary batteries. In this paper, we propose using the
internal resistance of a secondary battery as a guide for the evaluation of secondary battery
performance. The internal resistance of a secondary battery is measured with low resistance
measurement techniques. Development of such a tester has already completed.
1. Introduction
The advances made in the miniaturization of electronic devices and in constructing the
communications infrastructure have led to the rapid spread of compact, high-performance
cordless equipment, such as portable telephones and notebook computers. In addition,
uninterruptible power supplies (UPSs) are being installed in facilities where equipment cannot
be allowed to stop operating due to a power failure. Secondary batteries that allow repeated
use through recharging are used in such cordless equipment and UPSs, and demand for such
batteries is increasing as the market for such equipment expands. As a secondary battery
undergoes repeated charge/discharge cycles, the capacity of the battery begins to decrease due
to the effects of deterioration of the chemical matter inside the battery. Consequently, the
continuous discharge time of the battery is reduced, which can hinder the operation of the
equipment in which it is being used. This phenomenon is specifically seen as deterioration in
the performance of the secondary battery.
Generally, in order to accurately evaluate the deterioration of a secondary battery, it is necessary
to perform a charge/discharge test and measure the capacity of the battery. While this method
can accurately determine the state of the secondary battery, the test takes a good deal of time to
perform. Therefore, there is a need for a test method that can be used to evaluate the
performance of a secondary battery easily and quickly. Research now indicates that there is a
correlation between a decrease in a secondary battery's capacity and an increase in its internal
Technical Report