Abstract: Provided is a cell frame structure comprising: a rectangular panel-shaped outer frame having a rectangular opening in the center; and a rectangular inner frame, the inner frame interlocking onto the rear surface of the outer frame around the opening thereof to form a flow cell. The flow cell is preferably assembled into a cell frame by the inner frame interlocking onto the rear surface of the outer frame while covering the rim of a bipolar plate, the front-side rim of which is seated around the rear surface opening of the outer frame.

Abstract: According to one embodiment of the present invention, the method for controlling the pump speed of a redox flow battery for transferring an electrolyte stored in an electrolyte tank to a cell stack comprises the steps of: measuring the input power and/or the output power of the redox flow battery; measuring the charging power and/or the discharging power of the redox flow battery; calculating the power loss of the redox flow battery by using the difference between the input power and the charging power, or the difference between the output power and the discharging power; and adjusting the pump speed according to the power loss.

Abstract: The present invention relates to a redox flow battery, and more particularly, to a redox flow battery which is charged and discharged by supplying a positive electrolyte and a negative electrolyte to a battery cell using an active material containing vanadium and a cation exchange membrane, in which the positive electrolyte and the negative electrolyte contain vanadium ions as active ions, the difference in volume between the positive electrolyte and the negative electrolyte is maintained at 10% or less, and the total concentration of anions in the negative electrolyte is higher than the total concentration of anions in the positive electrolyte, whereby the transfer of water in the battery is controlled and a change in the volume of the electrolytes is minimized.

Abstract: According to one embodiment of the present invention, the method for controlling the pump speed of a redox flow battery for transferring an electrolyte stored in an electrolyte tank to a cell stack comprises the steps of: measuring the input power and/or the output power of the redox flow battery; measuring the charging power and/or the discharging power of the redox flow battery; calculating the power loss of the redox flow battery by using the difference between the input power and the charging power, or the difference between the output power and the discharging power; and adjusting the pump speed according to the power loss.

Abstract: The present invention relates to a redox flow battery and, more specifically, to a redox flow battery comprising an anolyte, a catholyte, and an ion exchange membrane, wherein the anolyte and the catholyte respectively comprise an electrolyte containing a Cl? ion and an active material containing a vanadium ion, and the electrolyte comprises at least one side reaction inhibitor selected from the group consisting of a metal phosphate, a metal hydrochloride and a metal sulfate.

Abstract: A method for measuring an electrolyte balance of a redox flow battery may include: charging the redox flow battery by applying a current to a stack; measuring temperatures of an anode electrolyte solution and a cathode electrolyte solution while the redox flow battery is charged; calculating a temperature change rate of the anode electrolyte solution over time and a temperature change rate of the cathode electrolyte solution over time; deciding a first change time corresponding to an inflection point of the temperature change rate of the anode electrolyte solution over time and a second change time corresponding to an inflection point of the temperature change rate of the cathode electrolyte solution over time; and calculating an average electrolyte oxidation number of the redox flow battery, using the first change time, the second change time, an oxidation number of the anode electrolyte and an oxidation number of the cathode electrolyte.

Abstract: Disclosed is a carbon structure electrode for redox flow batteries, which includes a plurality of spherical macropores formed on a surface of a polymer-derived carbon structure and inside the polymer-derived carbon structure so as to allow electrolyte migration. The carbon structure electrode for redox flow batteries has excellent electrical conductivity and enables cost reduction through a simplified preparation process.

Abstract: The present invention relates to a redox flow battery, and more particularly, to a redox flow battery which is charged and discharged by supplying a positive electrolyte and a negative electrolyte to a battery cell using an active material containing vanadium and a cation exchange membrane, in which the positive electrolyte and the negative electrolyte contain vanadium ions as active ions, the difference in volume between the positive electrolyte and the negative electrolyte is maintained at 10% or less, and the total concentration of anions in the negative electrolyte is higher than the total concentration of anions in the positive electrolyte, whereby the transfer of water in the battery is controlled and a change in the volume of the electrolytes is minimized.

Abstract: A method and apparatus for controlling operation of a redox flow battery. The method of controlling operation of a redox flow battery includes obtaining a diffusivity of anolyte ions with respect to a separator, obtaining a diffusivity of catholyte ions with respect to the separator, determining electrolyte diffusivities depending upon a state of charge value of the redox flow battery based on the diffusivity of the anolyte ions and the diffusivity of the catholyte ions, determining a minimum state of charge value and a maximum state of charge value of the redox flow battery based on the electrolyte diffusivities, and setting operating conditions of the redox flow battery based on the minimum state of charge value and the maximum state of charge value. The method and apparatus for controlling operation of a redox flow battery can prevent reduction in capacity of the redox flow battery.

Abstract: A system for evaluating a redox flow battery according to an embodiment of the present disclosure includes: a control unit configured to control the path of a flow channel connected between a detection cell and the redox flow battery or a flow channel connected between the detection cell and an agitator; and an evaluation unit configured to evaluate any one of the state of charge, capacity fade and oxidation number balance of an electrolyte, which is used in the redox flow battery, by measuring a current or voltage of the detection cell based on the controlling of the path by the control unit. According to the present disclosure, the capacity fade problem of a redox flow battery can be quickly coped with by evaluating the information of the positive and negative electrode electrolytes on battery capacity fade and information about the valence balance of the electrolytes in situ.

Abstract: A method and apparatus for controlling operation of a redox flow battery. The method of controlling operation of a redox flow battery includes obtaining a diffusivity of anolyte ions with respect to a separator, obtaining a diffusivity of catholyte ions with respect to the separator, determining electrolyte diffusivities depending upon a state of charge value of the redox flow battery based on the diffusivity of the anolyte ions and the diffusivity of the catholyte ions, determining a minimum state of charge value and a maximum state of charge value of the redox flow battery based on the electrolyte diffusivities, and setting operating conditions of the redox flow battery based on the minimum state of charge value and the maximum state of charge value. The method and apparatus for controlling operation of a redox flow battery can prevent reduction in capacity of the redox flow battery.

Abstract: Disclosed are a method and apparatus for analyzing an electrolyte of a redox flow battery. The method includes passing a first electrolyte solution or a second electrolyte solution through each of a first auxiliary cell and a second auxiliary cell connected to a main cell and a storage tank, closing at least one of the first auxiliary cell and the second auxiliary cell, applying current to the first auxiliary cell and the second auxiliary cell; creating data by measuring a voltage between the first auxiliary cell and the second auxiliary cell, and analyzing an electrolyte contained in the electrolyte solution in the first auxiliary cell or the second auxiliary cell based on variation in the voltage between the first auxiliary cell and the second auxiliary cell according to time. According to the present invention, information on an electrolyte can be obtained more efficiently and easily.

Abstract: Disclosed is a carbon structure electrode for redox flow batteries, which includes a plurality of spherical macropores formed on a surface of a polymer-derived carbon structure and inside the polymer-derived carbon structure so as to allow electrolyte migration. The carbon structure electrode for redox flow batteries has excellent electrical conductivity and enables cost reduction through a simplified preparation process.

Abstract: Disclosed are a redox flow battery system and a control method for the same. In the redox flow battery system, an oxidation number is controlled by injecting at least one of an oxidant and a reducer into at least one of a cathode side and an anode side using a measured oxidation number of the electrolyte. Therefore, even though an oxidation number balance is inevitably broken, since an initial concentration of vanadium ion, that is, an average oxidation number is maintained without a large change in the concentration, efficiency and stability of a battery may be promoted, and the oxidation number balance may be monitored in real time and the oxidation number balance may be recovered without a separate process of separating electrolytes to entirely mixing the electrolytes, or the like, that is, without stopping a function of the battery, thereby facilitating maintenance and control of performance of the battery.

Abstract: Disclosed herein is a redox flow battery, and more particularly, a cell frame channel design capable of efficiently distributing an electrolyte. The present invention provides a cell frame of a redox flow battery providing an electrolyte to an electrode, the cell frame of a redox flow battery including: an electrolyte inlet part and an electrolyte outlet part disposed at both side surfaces of the electrode, respectively; a distribution channel connected to the electrolyte inlet part and dividing the electrolyte into a plurality of channels; a buffer channel formed in a shape in which the buffer channel is connected to an end of each distribution channel and a channel width thereof is increased toward the electrode; a mixing zone formed between the buffer channel and the electrode to mix electrolytes flowed from the buffer channels with each other.

Abstract: Disclosed herein are a redox flow battery and a cell frame. In a cell frame of a redox flow battery, the cell frame comprising: a pair of unit frames adhered to each other; a protection plate shared by the unit frames, wherein each unit frame includes an electrolyte channel formed on a contact region of the unit frame with the protection plate; and a bipolar plate on which an electrolyte flows, wherein the electrolyte is supplied through the electrolyte channel. The cell frame has an integration type structure in which the protection plate is positioned in the cell frame, such that leakage of the electrolyte may be effectively prevented.

Abstract: The present invention provides a fuel cell bipolar plate in which an air gap or a material layer having a heat transfer coefficient lower than that of the bipolar plate is provided so as to reduce total amount of liquid water generated in a fuel cell, thereby preventing the occurrence of flooding and reducing the time required for cold start, enhancing durability, decreasing parasitic purge requirements, and enhancing operational stability.

Abstract: The present invention provides an apparatus and method for purging residual water and hydrogen during shutdown of a fuel cell, which can reduce the time required for purging residual water and hydrogen during shutdown of a fuel cell by opening and closing outlet lines of an anode and a cathode in a short period of time using solenoid valves.

Abstract: The present invention provides a fuel cell bipolar plate in which an air gap or a material layer having a heat transfer coefficient lower than that of the bipolar plate is provided so as to reduce total amount of liquid water generated in a fuel cell, thereby preventing the occurrence of flooding and reducing the time required for cold start, enhancing durability, decreasing parasitic purge requirements, and enhancing operational stability.

Abstract: A composite gasket for fuel cell stack comprises two rows of beads and a support which can improve mountability and sealing property and reduce the assembly pressure by using materials having low hardness with reduced volume. This invention also relates to a structure for the assembly of the composite gasket.