NOVELTY - Electrochemical cell comprises a first electrode compartment configured to contain a first electrochemically active fluid, at least a portion of a wall of the first electrode compartment comprising an ion-exchange medium; and a second electrode compartment configured to contain a second electrochemically active fluid, at least a portion of a wall of the second electrode compartment comprising the ion-exchange medium.    USE - The electrochemical cell is useful as electrochemical energy generation device.    ADVANTAGE - The use of electrochemically active fluids as the electrode(s) of energy generation devices can provide a variety of advantages. For example, the ability to flow the cathode and/or anode into a pre-assembled, fixed volume electrode compartment can simplify the assembly process. Electrochemically active fluid(s) can be easily and economically fabricated into electrodes by filling a space determined by the design of the battery. That is, the electrochemically active fluid(s) can be poured, injected, extruded or otherwise deformed under a gravitational force or other applied force into a space in a battery construction to form an electrode. Because the electrochemically active fluids conform to the outline of their container, the use of such materials can allow one to easily scale the size of the cell for a desired application and/or produce cells with large variations in form factor, relative to traditional battery assembly methods which can involve, for example, successively depositing layers of materials.    DETAILED DESCRIPTION - Electrochemical cell comprises a first electrode compartment configured to contain a first electrochemically active fluid, at least a portion of a wall of the first electrode compartment comprising an ion-exchange medium; and a second electrode compartment configured to contain a second electrochemically active fluid, at least a portion of a wall of the second electrode compartment comprising the ion-exchange medium, where at least one of the first and/or second electrode compartments is configured such that an electrochemically active fluid can be flowed into the compartment, the first and/or second electrochemically active fluids comprises at least one of a semi-solid and a redox active ion-storing liquid, and the electrochemical cell is configured such that, during operation, none of at least one of the first and second electrochemically active fluids is transported out of the first or second electrode compartment, or, less than about 20 wt of at least one of the first and second electrochemically active fluids is transported out of the first or second electrode compartment; or electrochemical cell, comprises a first electrode compartment configured to contain a first electrochemically active fluid comprising at least one of a semi-solid and a redox active ion-storing liquid, at least a portion of a wall of the first electrode compartment comprising an ion-exchange medium; and a second electrode compartment configured to contain a second electrochemically active fluid comprising at least one of a semi-solid and a redox active ion-storing liquid, at least a portion of a wall of the second electrode compartment comprising the ion-exchange medium, where the electrochemical cell is configured such that, during operation, none of at least one of the first and second electrochemically active fluids is transported out of the first or second electrode compartment, or, less than about 20 wt of at least one of the first and second electrochemically active fluids is transported out of the first or second electrode compartment, and the first and second electrochemically active fluids have a steady-state shear viscosity of less than about 1.5x106 cP. An INDEPENDENT CLAIM is a method of assembling an electrochemical cell comprising flowing a first electrochemically active fluid into a first electrode compartment; flowing a second electrochemically active fluid into a second electrode compartment; and sealing at least one of the first and second electrode compartments, where at least one of the first and second electrochemically active fluids comprises a semi-solid or a redox active ion-storing liquid.