Pressure Monitoring Cell for Constrained Battery Electrodes

Testing of improved battery components and new electrochemical energy storage materials in a coin cell format as a test cell is becoming the state of the art. The pressure on the electrode surfaces inside an electrochemical cell is one of the important parameters for high ionic/electronic conductivity and the cyclic lifetime. A self-designed pressure monitoring cell allows both applying an adjustable pressure and monitoring the state of charge-dependent cell pressure during cycling. The load cell shows a reciprocal behavior of the temperature sensitivity dependent on the ambient temperature and requires constant temperature conditions while monitoring the cell pressure. Further, dependent on the initial cell pressure, the relaxation time of the assembled pressure monitoring cell must be considered. The present paper describes the setup, the influence of the environment temperature and the mechanical relaxation of the pressure monitoring cell. The first cycling results, using an NCM/graphite coin cell, demonstrate the functionality of the pressure monitoring cell measuring the cell's pressure as a function of the C-rate.