Quantitative risk assessment of China's first liquid hydrogen refueling station.

Hydrogen refueling stations (HRSs) are among the most important infrastructures for fuel cell vehicles. However, the safety issue of HRSs has become a key constraint to the wide application and development of hydrogen energy. This article presents a quantitative risk assessment of the first liquid HRS (LHRS) in China and conducts a comprehensive assessment in terms of both individual (IR) and societal risks (SRs). The results showed that both the IRs and SRs related to the LHRS exceeded the risk acceptance criteria. The rupture of the flexible hose of the dispenser and the leak from the compressor are the main contributors to these risks. On the other hand, implementing appropriate mitigation measures on the level of the LHRS dispenser and compressor, including the addition of breakaway couplings in the flexible hose of the dispenser, the installation of hydrogen detection sensors, the arrangement of automatic and manual emergency shutdown buttons, and the elevation of the compressor, is capable of reducing the risk of the LHRS to be within the risk acceptance criteria.

Optimization of Interface Materials between Bi2Te3-Based Films and Cu Electrodes Enables a High Performance Thin-Film Thermoelectric Cooler.

Thermoelectric interface materials (TEiMs) are key to optimizing the electrical contact and stability of the interface between thermoelectric material and metal electrode in high-performance thin-film thermoelectric coolers (TECs). Herein, we explored TEiMs applicable to representative Bi-Te films and found that Cr and Ag are effective TEiMs for p-type Bi0.5Sb1.5Te3 and n-type Bi2Te3, respectively. By introducing 200 nm Cr and 200 nm Ag as TEiMs for p-type Bi0.5Sb1.5Te3/Cu and n-type Bi2Te3/Cu interfaces, Cu diffusion is suppressed, and excellent electrical contact is achieved (1.81 × 10-12 Ω m2 for p-type and 3.32 × 10-12 Ω m2 for n-type) and remains stable after heat treatment (2.37 × 10-12 Ω m2 for p-type and 1.63 × 10-12 Ω m2 for n-type). Furthermore, the cooling flux of TECs with optimized TEiMs increases from 122.74 to 296.56 W/cm2, while the performance degradation caused by contact resistance decreases from 50.81 to 4.15%. In addition, our results show that diffusion occurs between not only Cu but also Ag and the thermoelectric material, as TEiMs diffuse slightly. The diffusion of Cu and Ag at the interface can optimize the electrical contact of Bi2Te3/Cu but strongly degrade the electrical contacts of Bi0.5Sb1.5Te3/Cu. Our work provides an optimal selection of TEiMs for high-performance Bi-Te thin film coolers and provides guidance for further miniaturization of devices.