Abstract: An electrode includes a carbon fiber, wherein the carbon fiber has a first region including a surface of the carbon fiber, when a cross section of the carbon fiber is analyzed by electron energy loss spectroscopy, the first region has peaks both around 285 eV and around 530 eV, and the first region is provided up to 10% of a diameter of the carbon fiber from the surface toward a center.

Abstract: A redox flow battery includes: a membrane; and electrodes that are disposed in a compressed state on both sides of the membrane and sandwich the membrane. The thickness x (?m) of the membrane and the compression ratio y (%) of the electrodes satisfy the following relation A or B: (A) when the electrodes are formed from carbon felt, y<x+60, 30?y?85, and 5?x?60 hold; (B) when the electrodes are formed from carbon cloth or carbon paper, y<1.2x+42, 10?y?85, and 5?x?60 hold, where y={1?(the thickness during compression/the thickness before compression)}×100.

Abstract: A redox flow battery includes: a membrane; and electrodes that are disposed in a compressed state on both sides of the membrane and sandwich the membrane. The thickness x (?m) of the membrane and the compression ratio y (%) of the electrodes satisfy the following relation A or B: (A) when the electrodes are formed from carbon felt, y<x+60, 30?y?85, and 5?x?60 hold; (B) when the electrodes are formed from carbon cloth or carbon paper, y<1.2x+42, 10?y?85, and 5?x?60 hold, where y={1?(the thickness during compression/the thickness before compression)}×100.

Abstract: The battery cell for a flow battery includes a cell frame including a frame including a through-window and a manifold serving as an electrolyte flow path, and a bipolar plate blocking the through-window; a positive electrode disposed on one surface side of the bipolar plate; and a negative electrode disposed on another surface side of the bipolar plate. In this battery cell, in the frame, a thickness of a portion in which the manifold is formed is defined as Ft; in the bipolar plate, a thickness of a portion blocking the through-window is defined as Bt; in the positive electrode, a thickness of a portion facing the bipolar plate is defined as Pt; in the negative electrode, a thickness of a portion facing the bipolar plate is defined as Nt; and these thicknesses satisfy Ft?4 mm, Bt?Ft?3.0 mm, Pt?1.5 mm, and Nt?1.5 mm.

Abstract: A redox flow battery includes a cell frame having a frame body in which a sealing groove is formed and a sealing member disposed in the sealing groove. The redox flow battery includes an adhesive that fixes the sealing member to the sealing groove, and a type A durometer hardness of the adhesive after curing is 100 or less. Preferably, the type A durometer hardness of the adhesive after curing is less than or equal to a type A durometer hardness of the sealing member.

Abstract: The battery cell for a flow battery includes a cell frame including a frame including a through-window and a manifold serving as an electrolyte flow path, and a bipolar plate blocking the through-window; a positive electrode disposed on one surface side of the bipolar plate; and a negative electrode disposed on another surface side of the bipolar plate. In this battery cell, in the frame, a thickness of a portion in which the manifold is formed is defined as Ft; in the bipolar plate, a thickness of a portion blocking the through-window is defined as Bt; in the positive electrode, a thickness of a portion facing the bipolar plate is defined as Pt; in the negative electrode, a thickness of a portion facing the bipolar plate is defined as Nt; and these thicknesses satisfy Ft?4 mm, Bt?Ft?3.0 mm, Pt?1.5 mm, and Nt?1.5 mm.

Abstract: An electrode for redox flow batteries, the electrode being formed of a carbon fiber aggregate including a plurality of carbon fibers. Each of the carbon fibers has a plurality of pleats formed in the surface thereof. The ratio of L1 to L2, that is, L1/L2, is more than 1, where L1 is the peripheral length of a cross section of the carbon fibers and L2 is the peripheral length of a virtual rectangle circumscribing the cross section of the carbon fibers.

Abstract: The battery cell for a flow battery includes a cell frame including a frame including a through-window and a manifold serving as an electrolyte flow path, and a bipolar plate blocking the through-window; a positive electrode disposed on one surface side of the bipolar plate; and a negative electrode disposed on another surface side of the bipolar plate. In this battery cell, in the frame, a thickness of a portion in which the manifold is formed is defined as Ft; in the bipolar plate, a thickness of a portion blocking the through-window is defined as Bt; in the positive electrode, a thickness of a portion facing the bipolar plate is defined as Pt; in the negative electrode, a thickness of a portion facing the bipolar plate is defined as Nt; and these thicknesses satisfy Ft?4 mm, Bt?Ft?3.0 mm, Pt?1.5 mm, and Nt?1.5 mm.

Abstract: Provided are a battery cell that can be produced efficiently. A frame body of each cell frame of a battery cell includes an inner peripheral recessed portion formed by reducing a thickness of a peripheral portion that surrounds an entire perimeter of the penetrating window so that the peripheral portion has a smaller thickness than other portions of the frame body. A bipolar plate of the battery cell includes an outer peripheral engaging portion that engages with the inner peripheral recessed portion, the outer peripheral engaging portion being a portion having a particular width and extending throughout an entire outer periphery of the bipolar plate.

Abstract: An electrode for redox flow batteries, the electrode being formed of a carbon fiber aggregate including a plurality of carbon fibers. Each of the carbon fibers has a plurality of pleats formed in the surface thereof. The ratio of L1 to L2, that is, L1/L2, is more than 1, where L1 is the peripheral length of a cross section of the carbon fibers and L2 is the peripheral length of a virtual rectangle circumscribing the cross section of the carbon fibers.

Abstract: The battery cell for a flow battery includes a cell frame including a frame including a through-window and a manifold serving as an electrolyte flow path, and a bipolar plate blocking the through-window; a positive electrode disposed on one surface side of the bipolar plate; and a negative electrode disposed on another surface side of the bipolar plate. In this battery cell, in the frame, a thickness of a portion in which the manifold is formed is defined as Ft; in the bipolar plate, a thickness of a portion blocking the through-window is defined as Bt; in the positive electrode, a thickness of a portion facing the bipolar plate is defined as Pt; in the negative electrode, a thickness of a portion facing the bipolar plate is defined as Nt; and these thicknesses satisfy Ft?4 mm, Bt?Ft?3.0 mm, Pt?1.5 mm, and Nt?1.5 mm.

Abstract: The battery cell for a flow battery includes a cell frame including a frame including a through-window and a manifold serving as an electrolyte flow path, and a bipolar plate blocking the through-window; a positive electrode disposed on one surface side of the bipolar plate; and a negative electrode disposed on another surface side of the bipolar plate. In this battery cell, in the frame, a thickness of a portion in which the manifold is formed is defined as Ft; in the bipolar plate, a thickness of a portion blocking the through-window is defined as Bt; in the positive electrode, a thickness of a portion facing the bipolar plate is defined as Pt; in the negative electrode, a thickness of a portion facing the bipolar plate is defined as Nt; and these thicknesses satisfy Ft?4 mm, Bt?Ft?3.0 mm, Pt?1.5 mm, and Nt?1.5 mm.

Abstract: A redox flow battery includes a cell frame having a frame body in which a sealing groove is formed and a sealing member disposed in the sealing groove. The redox flow battery includes an adhesive that fixes the sealing member to the sealing groove, and a type A durometer hardness of the adhesive after curing is 100 or less. Preferably, the type A durometer hardness of the adhesive after curing is less than or equal to a type A durometer hardness of the sealing member.

Abstract: A cell frame for a redox flow battery comprises: a bipolar plate; and a frame body provided at an outer periphery of the bipolar plate, the frame body including a manifold which penetrates through front and back surfaces of the frame body and through which an electrolyte flows, and at least one slit being formed on the front surface of the frame body and forming a channel of the electrolyte between the manifold and the bipolar plate, a cross sectional shape of the slit, in a longitudinal direction of the slit, having a width w and a depth h, the width w and the depth h satisfying (A) w?3 mm and (B) 1/8<h/w<1.

Abstract: A frame body for a redox flow battery is provided with a window. The expressions A>C, B>D, and (B/A)?0.2 are satisfied, where A represents the length of a long side of a rectangle that envelops the window, B represents the width of a horizontal frame corresponding to the long side, C represents the length of a short side of the rectangle, and D represents the width of a vertical frame corresponding to the short side.

Abstract: A cell frame for a redox flow battery comprises: a bipolar plate; and a frame body provided at an outer periphery of the bipolar plate, the frame body including a manifold which penetrates through front and back surfaces of the frame body and through which an electrolyte flows, and at least one slit being formed on the front surface of the frame body and forming a channel of the electrolyte between the manifold and the bipolar plate, a cross sectional shape of the slit, in a longitudinal direction of the slit, having a width w and a depth h, the width w and the depth h satisfying (A) w?3 mm and (B) 1/8<h/w<1.

Abstract: A bipolar plate for a battery has two surfaces on which a positive electrode and a negative electrode are to be disposed respectively. At least one of the surfaces of the bipolar plate is provided with a plurality of groove sections through which an electrolyte flows and a ridge section located between the groove sections that are adjacent to each other. The groove sections include an introduction groove section and a discharge groove section that are not in communication with each other. The ridge section includes an uneven portion configured to suppress sliding of the positive electrode or the negative electrode in a direction in which the adjacent groove sections are arranged in parallel. The uneven portion includes a rough surface provided on at least a part of a surface of the ridge section and having an arithmetical mean roughness Ra of 0.1 ?m to 10 ?m inclusive.

Abstract: A frame body for a redox flow battery is provided with a window. The expressions A>C, B>D, and (B/A)?0.2 are satisfied, where A represents the length of a long side of a rectangle that envelops the window, B represents the width of a horizontal frame corresponding to the long side, C represents the length of a short side of the rectangle, and D represents the width of a vertical frame corresponding to the short side.

Abstract: Provided are a battery cell that can be produced efficiently. A frame body of each cell frame of a battery cell includes an inner peripheral recessed portion formed by reducing a thickness of a peripheral portion that surrounds an entire perimeter of the penetrating window so that the peripheral portion has a smaller thickness than other portions of the frame body. A bipolar plate of the battery cell includes an outer peripheral engaging portion that engages with the inner peripheral recessed portion, the outer peripheral engaging portion being a portion having a particular width and extending throughout an entire outer periphery of the bipolar plate.

Abstract: The battery cell for a flow battery includes a cell frame including a frame including a through-window and a manifold serving as an electrolyte flow path, and a bipolar plate blocking the through-window; a positive electrode disposed on one surface side of the bipolar plate; and a negative electrode disposed on another surface side of the bipolar plate. In this battery cell, in the frame, a thickness of a portion in which the manifold is formed is defined as Ft; in the bipolar plate, a thickness of a portion blocking the through-window is defined as Bt; in the positive electrode, a thickness of a portion facing the bipolar plate is defined as Pt; in the negative electrode, a thickness of a portion facing the bipolar plate is defined as Nt; and these thicknesses satisfy Ft?4 mm, Bt?Ft?3.0 mm, Pt?1.5 mm, and Nt?1.5 mm.