Standard Article

System design and applications

Fuel Cell Technology and Applications

Alkaline fuel cells and systems (AFC)

  1. K. Strasser

Published Online: 15 DEC 2010

DOI: 10.1002/9780470974001.f304064

Handbook of Fuel Cells

Handbook of Fuel Cells

How to Cite

Strasser, K. 2010. System design and applications. Handbook of Fuel Cells. .

Author Information

  1. Siemens, Erlangen, Germany

Publication History

  1. Published Online: 15 DEC 2010

Abstract

Over a period of 20 years, starting from 1967, research and developmental work on alkaline fuel cells was conducted at Siemens with the aim of increasing power density of the cell, improving long-term behavior, cell function and design, decreasing cost and gather experience by testing laboratory models and prototypes. Based on Raney nickel as the anode catalyst and doped silver as the cathode catalyst, a cell voltage of 0.7 V at a current density of 400 mA cm−2 can be reached. Cell operating conditions are 80 °C and 2 bar reactant pressures (absolute H2 and O2). The cell is characterized by the dimensions 240 × 245 cm2 and an active area of 340 cm2. Reaction water is removed from the cell by an electrolyte circulation. It is evaporated and condensed in a slit-like regenerator by removing the waste heat. The fuel cell stack, electrolyte regenerator and electromechanical control unit form a compact module block, which yields power ratios of approximately 10 kg kW−1 and 8 l kW−1, respectively. Modules with 35, 60 and 70 cells and a power output of 1–7 kW have been realized and also power plants consisting of more modules with a power output of 20–100 kW and a voltage of more than 200 V. A 100 kW prototype fuel cell power plant was tested successfully as part of an air independent propulsion system in the U205 submarine of the German Navy from August 1988 to March 1989. But in spite of the positive results the polymer electrolyte fuel cell was preferred because of its better long-term behavior and higher power density. There is no doubt that the relatively high production cost will limit the application in special areas such as submarines in the short term.

Keywords:

  • air independent propulsion system;
  • active area;
  • alkaline fuel cell;
  • Apollo cell;
  • characteristic;
  • fuel cell module;
  • anode;
  • calorific value;
  • carbonyl nickel;
  • Carnot factor;
  • catalyst layer;
  • loading;
  • cathode;
  • cell conventional design;
  • bipolar;
  • diaphragm;
  • porous layer electrode;
  • cell voltage;
  • temperature dependence;
  • conductivity;
  • contact;
  • resistance;
  • pressure;
  • cost;
  • current voltage performance;
  • decentralized power supply;
  • degradation;
  • efficiency;
  • electrical;
  • electric interface;
  • electrolyte regenerator;
  • electromechanical control unit;
  • electric vehicles;
  • fuel cells as propulsion units for;
  • electrocatalysts;
  • oxygen reduction;
  • sintering;
  • electrochemical energy conversion;
  • electrochemical engineering;
  • electrode;
  • preparation;
  • electrode materials;
  • metals;
  • Raney alloys;
  • energy density;
  • energy source;
  • fuel cell stack;
  • fuel cells;
  • Gemini project;
  • alkaline fuel cells;
  • efficiencies;
  • electric vehicles;
  • gas diffusion electrodes;
  • fuel cells as propulsion units;
  • electric vehicles;
  • gas diffusion cathodes;
  • fuel cells;
  • heat transfer;
  • heating up time;
  • heat engines;
  • hydrogen;
  • hydrogen electrode;
  • hydrogen storage;
  • hydrogen supply;
  • inert gas removal;
  • inner resistance;
  • impurities;
  • land testing device;
  • long term behavior;
  • lifetime;
  • open circuit voltage;
  • oxygen electrode;
  • PEM fuel cell;
  • phosphoric acid fuel cells;
  • platinum-free electrodes;
  • power;
  • density;
  • output;
  • plant;
  • ratio;
  • potassium hydroxide solution;
  • pressure cushion;
  • production cost;
  • Raney nickel;
  • redundancy;
  • reaction water;
  • sealing;
  • silver nitrate;
  • sintering;
  • sintering of Ni particle;
  • shutdown;
  • supply interface;
  • supported Siemens electrode;
  • thermal engines;
  • transport losses;
  • units;
  • current;
  • length;
  • mass;
  • voltage;
  • Varta-DSK electrode;
  • vehicle propulsion