Catastrophic localized deflagration formation mechanisms and safety precautions in proton exchange membrane water electrolyzer
Aidong Tan, Jiayi Song, Xutao Qiu, Zhang Liu, Lifan Xia, Ju Chen, Feng Zhao, Gang Li, Xiaoyun Shi, Tingting Li, Ping Liu, Jianguo Liu
Abstract
Proton exchange membrane water electrolysis attracts worldwide attention as a promising technology for green H2 production and renewable energy storage, yet the safety considerations in the industrial-scale operations are largely overlooked. Herein, localized deflagration in 100 kW and 2 kW proton exchange membrane water electrolysis stacks are reported. Water-starvation induced by flow channel obstruction is identified as the cause of the incident. The incident is reproduced in single electrolyzers, with the membrane electrode assembly deflagration process captured in-situ and studied. Physicochemical analysis and simulations reveal that water-starvation reduces membrane conductivity by 100-fold, generating large Joule heating to elevate membrane electrode assembly temperature above 150 °C, which softens membrane and leads to perforation under thermomechanical stress, subsequent H2 - O2 mixing and deflagration. Safety precautions are established, including materials and component designs, and monitoring strategies, with methods enabling early warning of deflagration in a 5 kW differential pressure stack. This work proposes both the fundamental understanding of deflagration mechanisms and practical guidelines for safe industrial scale-up of proton exchange membrane water electrolysis technology. Proton exchange membrane water electrolysis promises green hydrogen production but safety risks in industrial operations remain unexplored. Here, the authors identify water-starvation as the cause of water electrolysis stack deflagration and establish safety precautions for industrial scale-up.