PEM fuel cell powersystems with efficient hydrogen generation

Patent metadata

Field	Value
Publication number	US-11404706-B2
Application number	US-201916722367-A
Country	US
Kind code	B2
Filing date	Dec 20, 2019
Priority date	Apr 14, 2016
Publication date	Aug 2, 2022
Grant date	Aug 2, 2022

Abstract

Methods and devices for generating power using PEM fuel cell power systems comprising a rotary bed reactor for hydrogen generation are disclosed. Hydrogen is generated by the hydrolysis of fuels such as lithium aluminum hydride and mixtures thereof. Water required for hydrolysis may be captured from the fuel cell exhaust. Water is preferably fed to the reactor in the form of a mist generated by an atomizer. An exemplary 750 We-h, 400 We PEM fuel cell power system may be characterized by a specific energy of about 550 We-h/kg and a specific power of about 290 We/kg.

First claim

The invention claimed is:

1. A method of producing power using a fuel cell power system, the method comprising: providing a closed cathode PEM fuel cell stack comprising a plurality of fuel cells, each cell having an anode side and a cathode side that enables operation of the cathode side at a pressure above ambient pressure;
feeding water from a first water storage during start-up and stopping water feed from the first water storage during normal operation;
using condensed water during normal operation;
to a rotary bed reactor to generate hydrogen by a hydrolysis of a fuel in the reactor;
routing hydrogen to the anode side of the fuel cell stack at a hydrogen flow rate sufficient for producing power and a recirculation hydrogen stream;
enriching the recirculation hydrogen stream exiting the anode with by converting water to a mist comprising a plurality of water droplets using an atomizer that is entrained by the recirculation hydrogen stream into the rotary bed reactor; and,
routing the water-enriched recirculation stream to the rotary bed reactor, wherein condensed water is removed from the cathode side of the fuel ell stack; and,
wherein enriching further comprises splitting the hydrogen generated in the rotary bed reactor into a hydrogen feed stream that is routed to the anode side of the fuel cell stack and an intermediate recirculation hydrogen stream that is routed to the atomizer.

2. A method of producing power using a fuel cell power system, the method comprising: providing a closed cathode PEM fuel cell stack comprising a plurality of fuel cells, each cell having an anode side and a cathode side that enables operation of the cathode side at a pressure above ambient pressure;
feeding water from a first water storage to a rotary bed reactor during start-up to generate hydrogen by a hydrolysis of a fuel in the reactor;
stopping water feed from the first water storage during normal operation,
using condensed water during normal operation; routing hydrogen to the anode side of the fuel cell stack at a hydrogen flow rate sufficient for producing power and a recirculation hydrogen stream;
enriching the recirculation hydrogen stream exiting the anode with water;
routing the water-enriched recirculation stream to the rotary bed reactor, wherein condensed water is removed from the cathode side of the fuel cell stack;
wherein enriching further comprises converting water to a mist having a plurality of water droplets; and,
wherein the atomizer is an ultrasonic water mist generator that is entrained by the recirculation hydrogen stream into the rotary bed reactor.

3. A rotary bed reactor a method comprising: providing a closed cathode PEM fuel cell stack comprising a plurality of fuel cells, each cell having an anode side and a cathode side that enables operation of the cathode side at a pressure above ambient pressure; feeding water from a first water storage to a rotary bed reactor to generate hydrogen by the hydrolysis of a fuel in the reactor; routing hydrogen to the anode side of the fuel cell stack at a hydrogen flow rate sufficient for producing power and a recirculation hydrogen stream; enriching the recirculation hydrogen stream exiting the anode with water; and, routing the water-enriched recirculation stream to the rotary bed reactor, wherein condensed water is removed from the cathode side of the fuel cell stack the reactor further comprising; an outer stationary housing having a water inlet in fluid communication with a water storage; a cylindrical insert rotatably disposed within the outer housing and having a plurality of feed openings in fluid communication with the water inlet of the stationary housing; a plurality of slits disposed in the walls of the cylindrical insert; and an outlet for removing hydrogen; and, a fuel provided inside said insert in the form of particles, wherein hydrogen is generated by the hydrolysis of the fuel with water and removed from the outlet and wherein a fraction of the reaction solid byproduct is preferential removed through the slits in the insert urged by the rotating movement of the insert.

4. The reactor of claim 3 wherein the fuel comprises lithium aluminum hydride.

5. The reactor of claim 3 wherein the fuel comprises an admixture of lithium aluminum hydride and an additive comprising at least one of AlCl 3 , MgCl 2 , BeCl 2 , CuCl 2 , LiCl, NaCl, and KCl.

6. The reactor of claim 3 wherein the amount of additive in the admixture is between 5 wt-% and 30 wt.-%.

7. The reactor of claim 3 further comprising an atomizer closely coupled to the water inlet to convert water to a water mist comprising a plurality of water droplets to be fed to the reactor.

Assignees

• Intelligent Energy Ltd

Inventors

• Stimits Jason L
• Barton Russell
• Knight Douglas A
• Fraser Iain M
• Huang Hao
• Withers-Kirby Sandra H
• Kleszyk Piotr Marcin
• Ostadi Hossein
• Elliott Zachary

Classifications

• H01M2008/1095

  Fuel cells with polymeric electrolytes · CPC title

• H01M8/04126

  Humidifying · CPC title

• H01M8/065

  by dissolution of metals or alloys; by dehydriding metallic substances · CPC title

• H01M8/04291

  Arrangements for managing water in solid electrolyte fuel cell systems (H01M8/04119 takes precedence) · CPC title

• H01M8/04225

  during start-up · CPC title