Electrolyte Management System

Japan Fuji Electric has developed a 100 kWe on-site system. To date, they have tested a 50 kW power plant using innovative cell design that improves electrolyte management. They tested this stack (154 cells) for about 2,000. They have tested 65, 50 kWe units for a total cumulative operating tome of over 1 million hours. They have tested 3, 500 kWe units for a total of 43,437 hours. Their latest design, FPIOOE, has been shown to have a net AC efficiency of 40.2% (LHV). 

As with lead-acid and Ni MH batteries, overcharging of lithium-ion batteries must be carefully controlled to prevent detrimental electrode or electrolyte decomposition. This is one of the problems that advanced battery management systems can obviate, thereby ensuring the safety of lithium-ion batteries even in extreme conditions [107]. 

Direct methanol fuel cell (DMFC) was developed in 1950s-1960s, based on the liquid alkaline or aqueous acid solution as the electrolyte. It converts the methanol directly into electricity, instead of using indirectly produced hydrogen from methanol through the reforming process. Today, DMFC commonly refers to as the one that employs PEM as the electrolyte. Fuel for DMFC is a dilute solution of methanol, usually 3-5 wt% in water. The size of DMFC can be considerably smaller than PEMFC because of the elimination of fuel processor, and complex humidification and heat management systems. The performance of DMFC is relatively low compared to that of PEMFC. 

The air management system is shown in Fig. 7.1b. A side channel compressor is used for low pressure experiments (below 130 kPa), while a centralized air compression plant is used to study the effect of ah pressure on stack performance (between 130 and 250 kPa). An important issue to be considered is the cell humidification to guarantee that the stack works properly, since the electrolyte membrane needs to be continuously hydrated (see Sects. 3.2 and 4.5). That humidification is... 

Cathodes and anodes have been integrated into separate electrolyte circulation systems. Electrolyte management consists of preventing alkafinization at the cathodes and acidification at the anodes by mixing anolyte and catholyte and thus neutralizing both electrolytes to pH 7. An additional advantage of mixing anolyte and catholyte is that anionic nutrients captured in the anolyte end up in the catholyte, and likewise, cationic nutrients end up in the anolyte. Thus, cathodes and... 

The electrolyte management and purification systems are housed in containers, together with the electrical power supply. If necessary, electricity cables and circulation ducts and pipes can be installed underground. 

Venkatesan, S., Gradinarova, L., Menjak, A., and Wang, H. (2004) Alkaline fuel cell pack with gravity fed electrolyte circulation and water management system. US Patent Application 2004-0161652. 

The electrolyte losses by corrosion of die metal components and decrease in capillary force with particle coarsening of the electrolyte matrix therefore, the internal resistance and the cathode polarization increase. The cathode polarization increases with not only electrolyte loss but also dissolution of the cathode itself. Improvement of the electrolyte management and cathode stability are key factors for improving the reliability and durabiUty of the MCFC systems [4,5,7-11]. 

Reiser, C.A. and R.D. Sawyer. 1988. Solid polymer electrolyte fuel cell stack water management system. U.S. Patent 4769297. 

All electrical functions include a faultless operation supplied by the mains as a TN/TT net with the allowed tolerances regarding disturbances or pulses (conforming with the specification VDE 0160). In addition the following properties can be specified control of the electrolyte pumping system, the automatic replenishment system, and registration of all battery data during operation by computer management. 

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