Automated stand for electrical testing and diagnostics of life characteristics of lithium-ion batteries

Lithium-ion batteries (LIB) are widely used as energy accumulators in the electrical power systems (EPS) of spacecraft. The article considers the automated bench SIA 12/24 for electrical tests and diagnostics of the resource characteristics of lithium-ion cells (LIC), on the basis of which the EPS LIB of spacecraft is developed and manufactured. LIC resource tests are the most time-consuming and lengthy, they are carried out in ground conditions for several months with repeated cycling of charge/discharge and cell temperatures until the conditions for completion of the tests are reached with periodic monitoring, measurement and registration of LIC parameters. The use of the automated bench, which makes it possible to carry out resource testing of LIC based on dynamic stress testing (DST), makes it possible to shorten the resource testing of LIC and thereby significantly accelerate the design and development of EPS LIB of spacecraft. The structure, the description of the component parts and the technical characteristics of the bench SIA 12/24 allowing to perform electrical tests simultaneously of twelve LIC are given. The principle of operation and technical characteristics of the original charging-discharge device with a load converter (CDD-LC) forming the basis of the bench are considered. The proposed original CDD-LC and load converter (LC) topologies with two-stage power conversion and stabilized bridge transformer converter (BTC) input voltage make it possible to automate the process of lithium-ion cells electric testing by automatically reproducing functionally necessary test modes and by ensuring energy saving in cells charging-discharge modes. For a two-stage power conversion CDD-LC, it is shown that the use of BTC input voltage stabilization gives the following benefits: - extension of the LIC attribute control ranges: current, voltage, power; - low dependency of static error of stabilization of LIC attributes and transition quality indicators on the type of LC load.