Automated battery test system

Abstract

Battery testing is required for a wide range of applications. This includes quality assurance, design verification and performance assessment purposes for battery manufacturers, validation purposes for battery users, and battery behavioural research purposes for engineers developing behavioural prediction algorithms. Regardless of the application, determining the behavioural characteristics of batteries is a non-trivial problem. The electrochemical processes of a battery are complex, involving many parameters that are non-linearly interrelated. Therefore it is important that a test system designed for investigating battery behaviour provides accurate and reliable control and data acquisition. Manual testing is a labour intensive and time-consuming process. Automated testing can alleviate the labour requirements, with the added advantages of limiting human error (through limited human involvement), maintaining consistency between tests and providing flexibility in test conduction time and test routine. This paper presents the architecture of an automated battery test system. The paper begins by providing details on battery testing procedures. A typical test cycle, where the battery passes through all operating phases of charge, float charge and discharge, is described. The battery testing technique of accelerated thermal ageing, a special case of cyclic testing, is also described. This allows the identification of the parameters that are to be acquired and controlled and hence provides the specification for the battery test system. A specific battery test system solution is presented, which was designed for conducting valve regulated lead acid battery behavioural research. The system employs commercial off the shelf (COTS) components. Versatility is a key attribute of the system. This versatility extends from the ability to accommodate various battery configurations (different number of blocks per string and number of strings) and battery types (single cells through to mono-blocks) to the ability to vary the way the test is conducted and the criteria for data acquisition.