R.T. Barton

Estimation of the residual capacity of maintenance-free leadacid batteries Part 1. Identification of a parameter for the prediction of state-of-charge

Abstract The ohmic resistance of maintenance-free leadacid batteries has been identified as an ideal parameter for the prediction of the state-of-charge using the a.c. impedance technique. The ohmic resistance has been found to mirror the change in specific gravity of the battery electrolyte when charged or discharged.

The estimation of the residual capacity of sealed lead-acid cells using the impedance technique

The problem of estimating the residual usable energy of a lead-acid cell has been intensified by the introduction of fully sealed units. These rely on the recombination of gaseous oxygen produced during overcharge at the positive electrode with the active material at the negative electrode. This introduction has removed the possibility of electrolyte density measurements, third electrode measurements and restricted residual capacity assessments to the two cell terminals. A method for this process is described using a parameter based on a characteristic frequency. The parameter is also a useful measure of cell ageing.

Faradaic impedance measurements of small magnitudes encountered in high capacity electrical storage cells

Gross errors in impedance measurements of high capacity electrical storage cells can be observed when using a commercial Frequency Response Analyser (FRA) coupled with an electrochemical interface. The magnitudes of these errors are discussed and an appropriate automatic calibration procedure is described which enables the correct impedance to be recorded at any frequency.

The impedance of 23 Ah Ni-Cd cells with sintered electrodes: measurements in the range 10 kHz-0.001 Hz as an indication of residual capacity

Impedance measurements on 23 Ah Ni-Cd cells at various residual capacity levels are described. These have been made using non-inductive connections coupled directly to a potentiostat and a frequency response analyser.The capacitive reactance at 0.39 Hz provided the best residual capacity indicator.

Impedance of the sintered nickel positive electrode

Impedance measurements have been made on a mini electrode disposed between two large (identical) counter electrodes. A general mechanism is obtained for the electrode behaviour from the experimental data. The electrode reaction is two step and complex. Where comparison is possible agreement is obtained with earlier work.

The residual capacity estimation of fully sealed 25 A h lead/acid cells

Abstract Impedance measurements on large, 25 A h, spiral-wound, fully sealed lead/acid cells in the frequency range 60 kHz - 1 mHz are discussed. A residual cap

The electrotechnology of the nickel positive electrode: a review of the recent literature

Abstract A review is presented of the very recent electrotechnology of the nickel positive electrode. The majority of the literature covered is from the 1980s and 61 references are noted.

Prospects for the application of fuel cells in electric vehicles

Abstract For a hybrid vehicle the use pattern has large effect on the vehicle design. If the vehicle is to be used extensively on the motorway then a continuous high power is required. For the case of a fuel cell battery hybrid vehicle this would require a large fuel cell ( > 30 kW) to meet the sustained high power demand. The current high materials and fabrication cost of most fuel cells prohibits the commercial development of such a system. Consequently if fuel cell vehicles are to enter a ‘clean car’ market, earlier rather than later, alternative configurations must be sought and compromises in terms of performance are inevitable.

Cadmium - A review of the recent literature

Abstract Recent electrotechnological aspects of the cadmium electrode have been reviewed. Forty-four references are included and the electrode characteristics i

The impedance of the porous cadmium electrode in alkali

Abstract The porous cadmium electrode in alkali has been studied using the impedance technique applied to minielectrodes (area, 1 cm2) of conventional sintered structure. It is shown that in a wide frequency domain the electrode behaviour confirms to that of a filmed porous electrode under charge-transfer and diffusion control. In the lower frequency domain the electrode behaviour is more complicated and it is concluded that the frequency response was modified by intruding phase formation effects which were relaxed out at the higher frequencies.