Teledyne operating instructions Operational Theory Model 3300TB, Anatomy of a Micro-Fuel Cell

2 Operational Theory Model 3300TB

Micro-Fuel Cell is therefore a hybrid between a battery and a true fuel cell. (All of the reactants are stored externally in a true fuel cell.)

2.2.2 Anatomy of a Micro-Fuel Cell

The Micro-Fuel Cell is made of extremely inert plastic (which can be placed confidently in practically any environment or sample stream). It is effec- tively sealed, though one end is permeable to oxygen in the sample gas. At the permeable end a screen retains a diffusion membrane through which the oxygen passes into the cell. At the other end of the cell is a connector and temperature compensation network (restrictors and thermistor) on a printed circuit board.

Refer to Figure 2-1, Basic Elements of a Micro-Fuel Cell, which illus- trates the following internal description.

Electrical C onnector

Circuit Board

with tem perature com pensation network.

Anode

Cathode

Teflon M embrane

Screen

Clam p

Figure 2-1. Basic Elements of a Micro-Fuel Cell (not to scale)

At the sensing end of the cell is a diffusion membrane, whose thickness is very accurately controlled. Near the diffusion membrane lies the oxygen sensing element—the cathode.

The anode structure is larger than the cathode. It is made of lead and is designed to maximize the amount of metal available for chemical reaction.

The space between the active elements is filled by a structure saturated with electrolyte. Cathode and anode are wet by this common pool. They each have a

2-2 Teledyne Analytical Instruments