Boil-off gas management for onboard LH₂ in hydrogen-powered vehicles

Liquid hydrogen storage has the potential to address both the driving range limitations and high-pressure safety concerns associated with compressed hydrogen storage. However, the boil-off issue poses a significant challenge, limiting the adoption of liquid hydrogen storage for onboard applications in hydrogen-powered vehicles. This paper proposes a boil-off gas management solution that integrates a metal-organic framework tank, which serves as buffer storage to temporarily adsorb hydrogen boil-off gas and release it to the hydrogen powertrain when needed, enabling the recovery and utilization of boil-off hydrogen. A case study was conducted, and the analysis indicates that increasing the operating pressure from 0.5 MPa to 0.8 MPa improves the usable hydrogen storage capacity of the buffer storage tank by approximately 32%. Additionally, an enhanced operating mode incorporating liquid hydrogen cooling is proposed, increasing the buffer storage capacity by 68% compared to baseline performance. Furthermore, the hydrogen recycling capacity increases with higher buffer storage tank pressure, showing an improvement of more than 30% at 0.8 MPa compared to 0.5 MPa, resulting in a substantial reduction in tank volume and weight. This reduction is particularly beneficial for onboard vehicle applications, where space is limited.