Modeling a Hybrid Reformed Methanol Fuel Cell–Battery System for Telecom Backup Applications

Abstract

In this paper, a hybrid reformed methanol fuel cell–battery system for telecom backup applications was modeled in MATLAB Simulink. The modeling was performed to optimize the operating strategy of the hybrid system using an energy management system with a focus on a longer lifetime and higher fuel efficiency for the fuel cell, while also keeping the state-of-charge (SOC) of the battery within a reasonable range. A 5 kW reformed methanol fuel cell stack and a 6.5 kWh Li-ion battery were considered for the hybrid model. Moreover, to account for the effects of degradation, the model evaluated the performance of the fuel cell both in the beginning of life (BOL) and after 1000 h and 250 start–stop cycling tests (EOT). The energy management system (EMS) was characterized by 12 operating conditions that used the battery SOC, load requirements and the presence or absence of grid power as the inputs to optimize the operating strategy for the system. Additionally, the integration of a 400 W photovoltaic (PV) system was investigated and was able to supplement the battery SOC, thereby increasing the stability and reliability of the system. However, extensive power outages during the night could lead to low battery SOC and, therefore, critical operating conditions and the extended use of the fuel cell. The model also predicted the methanol consumption for different scenarios.