Abstract: The present invention relates to a system for characterizing at least one of the oxidation stability and the thermal stability of a fuel sample. The system comprises at least a device (MSIE) for performing an electrochemical impedance spectroscopy measurement in the sample, and a device (MDM) for determining deposit mass forming in the fuel sample. The invention further relates to a method for characterizing at least one of the oxidation stability and the thermal stability of the fuel over time, from measurements performed by the system according to the invention.

Abstract: The invention is a redox flow battery (1000) comprising n electrochemical cells 300 that are electrically connected in series (300) with each cell including a cathode (310) and an anode (320) that are separated by a membrane (330) and that are respectively passed through by a catholyte and an anolyte originating from a catholyte tank (110) and an anolyte tank (120). The cells are fluidically connected in parallel. The invention is also a system for decreasing bi-pass currents including means (700) for injecting a gas into the inlet ducts (401) and outlet ducts (501) of the cathode and anode of (n?1) cells to form gas bubbles; and a device (800) for removing the gas bubbles, placed, on the inlet ducts of the cathode and anode of the (n?1) cells, downstream of the means for injecting the gas and upstream of the cathode and anode of the cells.

Abstract: The invention is a redox flow battery (1000) comprising n electrochemical cells 300 that are electrically connected in series (300) with each cell including a cathode (310) and an anode (320) that are separated by a membrane (330) and that are respectively passed through by a catholyte and an anolyte originating from a catholyte tank (110) and an anolyte tank (120). The cells are fluidically connected in parallel. The invention is also a system for decreasing bi-pass currents including means (700) for injecting a gas into the inlet ducts (401) and outlet ducts (501) of the cathode and anode of (n?1) cells to form gas bubbles; and a device (800) for removing the gas bubbles, placed, on the inlet ducts of the cathode and anode of the (n?1) cells, downstream of the means for injecting the gas and upstream of the cathode and anode of the cells.

Abstract: A method of estimating the internal state of a first electrochemical system for power storage is disclosed. The SoC and the electrochemical impedance are determined for different internal states of a second electrochemical system of a same type as the first electrochemical system being studied. An electrochemical impedance model is then defined as a function of the SoC and of parameters. The electrochemical impedance Z of the system studied is determined and its SoC is estimated using the model applied to electrochemical impedance Z.

Abstract: The method for determining the state of charge of a battery includes measurement of an electric parameter of the battery during a charging or discharging phase of the battery followed by placing the battery in open circuit during a rest period. During the rest period, at least two values of the voltage at the battery terminals are measured. An indicator is then calculated according to the electric parameter and to values of the voltage measured during the rest period, and the state of charge corresponding to this indicator is then determined by means of a calibration curve representative of the variations of the indicator as a function of the state of charge of the battery.

Abstract: The invention is a method for estimating the internal state of a system for the electrochemical storage of electrical energy, such as a battery. For various internal states of batteries of the same type as a battery being analysed, impedance measurements are carried out by adding an electrical signal to the current passing through the batteries. Then, an RC circuit is used to model the impedances. Next, a relationship is calibrated between the SoC (and/or the SoH) and the parameters of the RC circuit using multivariate statistical analysis. A measurement of the impedance of the battery under analysis is carried out which is modeled using the RC circuit. Finally, the relationship of the equivalent electric circuit defined for the battery being analysed is used to estimate the internal state of that battery.

Abstract: Method of estimating the internal state of an electrochemical system for electric power storage, such as a battery. The SoC and the electrochemical impedance are determined for various internal states of an electrochemical system of the same type as the electrochemical system studied. An electrochemical impedance model is then defined as a function of the SoC and of parameters. These parameters are calibrated through adjustment on the electrochemical impedance measurements obtained for the various internal states. The electrochemical impedance Z of the system studied is determined and its SoC is estimated using the model applied to electrochemical impedance Z.

Abstract: The method for determining the state of charge of a battery can be used during charging or discharging of the battery at constant current. It comprises placing the battery in open circuit during a recovery period until the voltage at the terminals of said battery stabilizes at a voltage plateau. Then a constant test voltage is applied to the battery terminals during a preset test period. The state of charge of the battery corresponds to the current measured at the end of the test period by means of a previously obtained calibration curve.

Abstract: The method for determining the state of charge of a battery includes measurement of an electric parameter of the battery during a charging or discharging phase of the battery followed by placing the battery in open circuit during a rest period. During the rest period, at least two values of the voltage at the battery terminals are measured. An indicator is then calculated according to the electric parameter and to values of the voltage measured during the rest period, and the state of charge corresponding to this indicator is then determined by means of a calibration curve representative of the variations of the indicator as a function of the state of charge of the battery.

Abstract: A non-invasive method and device for determining the electrical impedance of an electrochemical system for electric power is disclosed. The voltage and current are measured at terminals as a function of time, and these measurements are converted to signals dependent on frequency. The signals dependent on frequency are subjected to at least one segmentation. For each segment, a power spectral density of the current signal ?I dependent on frequency and the cross power spectral density of the voltage and current signals ?IV dependent on frequency are determined for each segment. The electrical impedance of the electrochemical system is determined by calculating a ratio dependent on frequency of a mean of the power spectral densities ?I dependent on frequency to a mean of the cross power spectral densities ?IV dependent on frequency.

Abstract: The method for determining the state of charge of a battery can be used during charging or discharging of the battery at constant current. It comprises placing the battery in open circuit during a recovery period until the voltage at the terminals of said battery stabilizes at a voltage plateau. Then a constant test voltage is applied to the battery terminals during a preset test period. The state of charge of the battery corresponds to the current measured at the end of the test period by means of a previously obtained calibration curve.