(US5759711-A)      A liquid-circulating battery comprises: (a) positive and negative electrodes; (b) a permeable membrane between the electrodes; (c) two porous carbon electrodes of a liquid-permeable type disposed in the positive and negative chambers; and (d) positive and negative electrolytic solutions circulated respectively into the positive and negative chambers, such that an oxidation-reduction reaction occurs causing charging and discharging. The permeable membrane is an ion-exchange membrane including as an ion exchanger layer a polymeric pellicle formed by crosslinking a halogenated alkylated aromatic polysulphone type polymer using a polyamine. The membrane is 0.1 - 120 m thick, has an ion exchange capacity of 0.3 - 0.8 milli-equivalents/gram of dry resin, and has a recurring unit represented at least by the following formula (I). The electrolytic solutions have a vanadium ion concentration of 0.5-8 mols/litre.    USE -   The battery is sued as a redox flow type cell battery.    ADVANTAGE -   The redox flow cell battery has a reduced cell resistance, increased power efficiency in a wide range of current densities and prolonged cycle of charge and discharge.    (EP790658-B1)      A liquid-circulating battery comprises: (a) positive and negative electrodes; (b) a permeable membrane between the electrodes; (c) two porous carbon electrodes of a liquid-permeable type disposed in the positive and negative chambers; and (d) positive and negative electrolytic solutions circulated respectively into the positive and negative chambers, such that an oxidation-reduction reaction occurs causing charging and discharging. The permeable membrane is an ion-exchange membrane including as an ion exchanger layer a polymeric pellicle formed by crosslinking a halogenated alkylated aromatic polysulphone type polymer using a polyamine. The membrane is 0.1 - 120 m thick, has an ion exchange capacity of 0.3 - 0.8 milli-equivalents/gram of dry resin, and has a recurring unit represented at least by the following formula (I). The electrolytic solutions have a vanadium ion concentration of 0.5-8 mols/litre.    USE -   The battery is sued as a redox flow type cell battery.    ADVANTAGE -   The redox flow cell battery has a reduced cell resistance, increased power efficiency in a wide range of current densities and prolonged cycle of charge and discharge.