Cell integration of sensors

Within Work package 3 of the SENSIBAT project, level 1 and level 2 sensors were integrated into Li-ion cells. To achieve this objective, in a first step level 1 sensors had to be adopted. This involved work on the encapsulation of the sensor to withstand the harsh operating conditions of these sensors within the electrolyte filled environment within the cell. Further, the feed-through for the level 1 sensor cells had to be optimized, allowing to measure pressure & temperature on multiple positions inside the battery. This feed through represents the material, dimensions and position of the wiring, guiding the multiple sensor signals from the insight of the cell to the outside.

Cells with level 2 sensors were also constructed, enabling the SENSIBAT partners to visualize the individual potential of the negative and positive electrode during the cell operation. While for standard Li-ion cell only the cell voltage can be followed – the incorporated level 2 sensor allows to separate between negative and positive electrode. This provides insights on the cells state of health, the electrode design and allows to gain important knowledge for cell aging processes. A sensor can only provide accurate cell data if he does not interfere with the cell and change the cells behaviour by his presence. To ensure this, next to the cells with sensors also cells without sensors were constructed and the electrochemical results of all constructed cells were compared. This comparison displayed no more than a minor impact on the cell performance by the presence of the sensors.