Design of the battery resistance measurement system

Battery resistance is an important index of the battery performance. At present, the main test method of battery resistance is the DC discharge method and AC testing method. The paper introduces the fundamental principles for measuring the battery resistance by AC testing method, and based on this method designs a practical and simple battery resistance measurement system. The system hardware consist of 1kHz AC current source, multiplier unit, measuring amplifier, phase detector, data acquisition unite, DCV reference, amplifiers, low-pass filter, precision full-wave rectifier, switch control circuit, electronic load circuit and tracking DC source and so on. The system software is designed by LabWindows/CVI virtual instrument software development environment, Using C programming language. The system software design uses the modulation design concept, between the module, the relative independence is convenient, flexible and expansion. System friendly interface is simple and easy to learn and use. We have used this test system measuring the model 0191A dry cell, and the test results show that the system can satisfy the requirement of dry battery impedance test. According to the principle of design, appropriately changes circuit parameters, the system can measure other batteries. The system has good practical value and popularized significance.