Flat cell voltages

The electricity-producing system of electric fishes is built as follows. A large number of flat cells (about 0.1 mm thick) are stacked like the flat unit cells connected in series in a battery. Each cell has two membranes facing each other. The membrane potentials of the two membranes compensate for each other. In a state of rest, no electrostatic potential difference can be noticed between the two sides of any cell or, consequently, between the ends of the stack. The ends of nerve cells come up to one of the membranes of each cell. When a nervous impulse is applied from outside, this membrane is excited, its membrane potential changes, and its permeability for ions also changes. Thus, the electrical symmetry of the cell is perturbed and a potential difference of about 0.1 V develops between the two sides. Since nervous impulses are applied simultaneously to one of the membranes in each cell, these small potential differences add up, and an appreciable voltage arises between the ends of the stack. 

La photovoltaic cells, the same redox reaction, OX + e = KED, may be used for both the anode and the cathode. Figure 10-33 shows an eneigy diagram of an operating photovoltaic cell this cell consists of a metallic cathode and a photoexcited n-type semiconductor anode. The electromotive force (the open cell voltage), ph > approximately equals the difference between the flat band potential of... 

This high-energy density battery is ideal for use, as button cell, in such electronic devices as cameras, calculators and watches. It features a flat, constant voltage of 1.5 V and a very low self-discharge... 

Mercuric oxide dry-cell batteries are often used where a flat discharge voltage and long life are required, such as in watches and cameras. The two half-ceU reactions that occur in the battery are... 

No disproportionation reaction such as Mn - > Mtf + Mn Muring cycling Easily protected from over charging by monitoring cell voltage Flat discharge profile which does not need a DC/DC converter FuU-chargable up to 4 V without concern for electrolyte oxidization decomposition... 

The electrochemical cell itself consisted of essentially a flat cell, fixed inside in the optimal position within the EPR cavity so as to ensure maximum sensitivity. The working electrode employed was either a platinum mesh [102] or later, a partly laminated gold mesh [103, 104], An AglAgCl electrode was used as the reference, whilst two counter electrodes were employed to minimize oscillation of the cell voltage. The first counter electrode, a palladium sheet, is situated below the flat part of the cell, whilst the second, connected by a resistor to the potentiostat, is located above it. 

The results for the SoC calculated from OCV data are shown in Figure 1 c) and d). As expected calculating the SoC with OCV data resulted in large errors of up to 25% for the LFP cell. The reason for this is its flat voltage plateau at about 50% (Fig. 2 c). With a SoC error of only 2% this method was shown to be applicable for the NCM type. A disadvantage of OCV measurements is the time needed to reach a full relaxation of the cell voltage, which can take from 10 minutes to 2 hours. On the other hand the comparatively very low dependency of the OCV from internal resistance and temperature makes the method very robust. 

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