Temperature measurement in SOxC stacks

Title: Reduction of Degradation in a Stack of Joined High-Temperature Solid Oxide Cells

This patent describes a method and system for reducing degradation in high-temperature solid oxide cells (SOFC/SOEC) during operation or thermal treatment. The core of the invention is an impedance-based temperature management approach, in which cell temperatures and temperature gradients are not determined via conventional sensors but derived from electrical impedance measurements and used for process control.

Through continuous impedance monitoring – for example using electrochemical impedance spectroscopy (EIS) – the thermal conditions within the stack can be precisely adapted to the actual state of individual cells. This enables zone-specific, independent control of the heating zones and prevents critically high temperature differences that typically lead to material fatigue and performance loss.

The method provides several key advantages:

• reduced degradation and extended cell lifetime

• stable and homogeneous temperature distribution across the entire stack

• early detection of thermal deviations

• improved operational safety and reproducibility

• higher efficiency during conditioning, operation, and regeneration of SOFC and SOEC stacks

The impedance-based temperature control concept represents a significant advancement for the reliable operation of high-temperature fuel cells and electrolyzers. It combines advanced measurement techniques with intelligent control systems and makes a decisive contribution to increasing the robustness and performance of modern electrochemical energy systems.