HT‐PEM Fuel Cell System with Integrated Complex Metal Hydride Storage Tank

Abstract

A hydrogen storage tank based on the metal hydride sodium alanate is coupled with a high temperature PEM fuel cell (HT‐PEM). The waste heat of the fuel cell is used for desorbing hydrogen from the storage tank that in return feeds the fuel cell. ZBT has developed the HT‐PEM fuel cell, Max‐Planck‐Institut für Kohlenforschung the sodium alanate, and IUTA the hydrogen storage tank. During the experiments of the system the fuel cell was operated by load cycling from 165 up to 240 W. Approximately 60 g of hydrogen were delivered from the tank, which was charged with 2676.8 g of sodium alanate doped with 4 mol.% of TiCl3. This amount of hydrogen was desorbed in 3 h and generated a cumulated electrical energy of 660 Wh. In the first cycle 81.5 g of hydrogen were supplied during 3.69 h to the HT‐PEM fuel cell, which was operated nearly constant at 260 W. In the latter case the cumulated electrical energy was 941 Wh.

Sodium-based hydrides for thermal energy applications

“…The ultimate aim of this work is to take advantage of the lower operating pressure of Na 3 AlH 6 , compared to NaAlH 4 , to use the waste heat from a high-temperature proton exchange membrane (HT-PEM) fuel cell operating at *180°C to supply the necessary heat to release the H 2 from Na 3 AlH 6 which desorbs at 116°C and at 1 bar H 2 (47 kJ mol -1 H 2 ) [95]. The experience gained in the processing, handling and development of hydrogen storage tanks utilising several kilograms of NaAlH 4 [110][111][112][113][114] for hydrogen storage in mobile applications has been thoroughly explored and many of the issues involving heat transfer during cycling and safety concerns have been addressed. As such, this research can readily be extended to the alanate hexahydrides.…”

Metal hydrides for concentrating solar thermal power energy storage

“…If a waste heat source is available in the temperature range of 130 to 160 o C, then Na3AlH6 can also be used as the LTMH H2 storage material [81,84]. The enthalpy of H2 absorption is higher for Na3AlH6 (Habs = −47 kJ·mol −1 .H2) compared to NaAlH4 (Habs = −38.6 kJ·mol −1 .H2) and this may have design consequences for managing the higher thermal load during H2 absorption.…”

Aluminium alloy based hydrogen storage tank operated with sodium aluminium hexahydride Na3AlH6

“…Both theoretical [15,26,28] and practical investigations [32,33,39] were carried out to demonstrate the thermal coupling of NaAlH 4 based hydrogen storage tanks in combination with a HT-PEM fuel cell. While in one case air was proposed as a heat transfer medium between the tank and fuel cell [35], in other cases a liquid was used for the thermal coupling.…”