Principles of cell design

The design of the cell will affect all the figures of merit for an electrolytic process. Cell design will be considered in detail in section 2 5 but it should be noted here that the principal factors determining the electrolysis performance will be the presence or absence of a separator and its type (porous diaphragm or ion-selective membrane), the mass transport regime, the arrangement and form of the electrodes (hence, the anode-cathode gap and potential distribution at both electrodes) and the materials of construction  

Chemical engineering recognizes three broad types of reactor (Fig. 2.6). These are now described and design equations are developed in a simplified manner, using the principle of mass balance over the reactor  

The simple batch reactor is charged with the reactants which are then well mixed and left for a period for the reaction to occur to some edle ntiin extent. The resulting solution is then discharged from the reactor and worked-up to isolate the product. The of reactants and product will 

Batch processing is clearly labour intensive and better suited to small-scale operations or those requiring intermittent supplies of product. 

There are a number of modes of operation for reactors, with respect to the electrolyte manifolds and reactant feed-product withdrawal schedules. Here, we wilt consider the design equations for four common modes of operation (Fig. 2.7), expressions being written in terms of reactant concentration for a process under complete mass transport control. 

4 PRINCIPLES OF CELL DESIGN 2.4.1 Classical chemical reaction engineering 

Chemical engineering recognizes three broad types of reactor (see Fig. 2.3). These are now described. 

This system consists of a well stirred tank so that the composition throughout the reactor is uniform but reactant is added continuously and a product stream is removed at the same rate. The exit stream will have the same composition as the fluid in the reactor. 

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Hence in this chapter we will first consider briefly the factors involved in costing an electrolytic process and discuss the various figures of merit. Then cell components and the principles of cell design will be discussed. 

The section will discuss some typical examples of these principles of cell design and each subsequent chapter will deal with cell design in the more specific context of the particular application. 

The general technology may be illustrated by the example of sodium production in the Down s cell. The electrolyte is a molten mixture of sodium chloride (40%) and calcium chloride (60 wt %) requiring a process temperature of about 600°C. The principle of cell design is shown in Fig. 4.4, although more... 

This chapter is intended to provide an overview of the varions aspects of manufacturing lithium-ion (Li-Ion) cells. While the basic principles of cell design and manufacture are well known, each manufacturer maintains proprietary, specific details of their cell designs and assembly and the equipment used in cell fabrication. Nonetheless, the overall principles and processes involved are detailed below. Figure 8.1 shows a schematic of the components of a cell (battery). 

In these studies, generally a very thin layer of solution is used to cover the electrode surface in order to minimize the reflective effect of the solvent and to make electrical contacts. On top of this solution layer, a Mylar film is used to enclose the solution to prevent solvent vaporization. The general principle of cell design is quite similar to that of TLCs described above except that the top cover of the cells must be spectroscopically transparent (for instance, replaced by a Mylar film here). 

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