The testing of a solar panels and photovoltaic cells as well is a very interesting method of NDTs (non destructive techniques) allowing the fast and safe inspection. Measuring method uses infrared thermography and this is known more than 10 years and is becoming increasingly important standard. Accurate thermographic images of photovoltaic cells reveal quickly and purposefully for example shunt effects, short circuits, faulty contacts etc.

This paper deals with measurement of negative electrodes with different additives in electrode active mass. The main aim of experiment was to find out if additives will have significant effect to imaginary part of impedance. Three electrodes were compared. The first electrode (nr.2) had titan dioxide additive, the second electrode (nr.3) had nano-size titan dioxide additive and the third electrode (nr.5) had the carbon type CR2996 additive. ExperimentalMeasurement method used was slightly modified electrochemical impedance spectroscopy. New method evolved from older one developed at our department of electrotechnology twenty years ago. This method required us to create our own electrodes with non-continuous system of parallel ribs, because to each rib two (voltage and current) wires are connected. So we can select ribs of electrode we wanted to measure (1,2).As it was told above, experimental electrodes with system of non-continuous parallel ribs (Fig. 1) were used. Ribs were fixed by epoxy resin. To each rib one voltage and one current wire were connected.Equivalent diagram of experimental electrode is at fig. 2. Rp means wire resistance that was measured before the experiment begins, Zk means corrosion impedance of interphase electrode/electrolyte, Zm means impedance of active mass. Measurement procedure is similar as one used in our experiments published lately. Measurement is composed of two steps, frequency dependency is measured between ribs 2-3. During first step current flows between ribs 1-4 and in second step the current flows between ribs 2-4. In first step we theoretically measure impedance of active mass Zm and

Following article deals with thermal phenomena in lead acid batteries. Possitive influance of negative active mass materials was tested on experimental electrodes, also different separators were used.