Measurement of the mechanical deformation of SOxC stacks

Title: Quality Assurance in the Production of Stacks Made from Solid Oxide Cells (SOxC)

This patent describes a method and system for quality assurance in the manufacturing of high-temperature solid oxide cell stacks (SOFC/SOEC). The key element is continuous monitoring of the stack during the joining process using multichannel impedance spectroscopy (EIS).

While the cell stack is joined inside a furnace under the influence of temperature and mechanical force – with a sealing material applied between the layers – the system cyclically measures electrical impedance at several externally positioned measurement points. From the recorded impedance values, software algorithms derive geometric parameters that allow conclusions about potential deformations of individual cells or of the entire stack. This information supports:

• control of the joining process to minimize unwanted deformation

• continuous real-time monitoring of stack geometry

• automated derivation of a quality assessment for each manufactured stack

In this way, conformity with quality requirements can be ensured already during production. Later performance losses caused by cell degradation due to geometric distortions are prevented.

The method increases the reliability, reproducibility, and stability of SOxC stack fabrication and strengthens production and quality standards for high-temperature fuel cell and electrolyzer stacks.