Experimental investigations on the bonding of alkaline electrolytic cells

Green hydrogen is becoming an increasingly relevant alternative to fossil fuels for various applications. Alkaline water electrolysis (AEL) is a promising technology to meet this growing demand. However, scaling up the production of AEL cells in a cost-efficient manner is challenging, as current cell designs are not optimized for automated assembly processes. This is a result of the conventionally required large number of individual parts such as screws, nuts, washers and isolation tubes for joining the half shells of one cell. To address this challenge, the present research investigates the feasibility of adapting the cell design by replacing the conventional screw-based joining processes with an adhesive-based design. As a first step, the required adhesive properties for use in AEL cell design are identified. Following this, four selected adhesives are experimentally analysed regarding their suitability. To accomplish this, adhesive samples are placed inside of an AEL cell and exposed to continuous cell operation for 10 hours. The adhesives are optically analysed and the Shore hardnesses and tensile shear strengths are compared before and after exposure. The results demonstrate the suitability of the investigated epoxy-based adhesives regarding the required chemical resistance and mechanical strength. To evaluate the feasibility of the selected adhesive, a 250 x 500 mm AEL cell demonstrator with this concept is operated in a test facility, proving the electrochemical feasibility and sufficient electrical insulation of this approach. However, the chemical resistance and especially the impermeability proved to be lacking, highlighting the necessity for further investigations into chemically resistant adhesives for the application in electrolyseur manufacturing. Overall, this research opens up the possibility for increasingly cost-effective and scalable AEL production processes, which is an influential factor for achieving a sustainable supply of green hydrogen.