Methods and systems are provided for manufacturing a bipolar plate for a redox flow battery. In one example, the bipolar plate is fabricated by a roll-to-roll process. The bipolar plate includes a non-conductive substrate that is coupled to a negative electrode on a first surface and coupled to a positive electrode on a second surface, the first surface opposite of the second surface.

This disclosure provides a manufacturing method for manufacturing a fuel cell separator. The manufacturing method includes: providing a material sheet including a fiber sheet, carbon particles, and a resin, the carbon particles and the resin being applied to the fiber sheet; and pressing the material sheet into a recess-projection shape by which a gas circulation passage is to be formed, and forming a top portion and a shift portion. In the pressing of the material sheet, the material sheet is pressed such that a draft of the top portion is higher than a draft of the shift portion.

An intermediate material of a thermoplastic prepreg for a fuel cell separation plate comprises a hydrophobic thermoplastic resin film and a fiber base. The hydrophobic thermoplastic resin film has a degree of crystallization of 1 to 20%, a thickness of 3 to 50 μm, and (iii) a content of an electroconductive material of 1 to 20 wt. %. The film is laminated on at least one surface of the fiber base. The thermoplastic prepreg for a fuel cell separation plate is manufactured by pressurizing the thermoplastic prepreg intermediate material at a temperature higher than the melting point of the hydrophobic thermoplastic resin film. A fuel cell separation membrane manufactured using the thermoplastic prepreg intermediate material and thermoplastic prepreg is thin and light-weight, and have a good durability.

An intermediate material of a thermoplastic prepreg for a fuel cell separation plate comprises a hydrophobic thermoplastic resin film and a fiber base. The hydrophobic thermoplastic resin film has a degree of crystallization of 1 to 20%, a thickness of 3 to 50 μm, and (iii) a content of an electroconductive material of 1 to 20 wt. %. The film is laminated on at least one surface of the fiber base. The thermoplastic prepreg for a fuel cell separation plate is manufactured by pressurizing the thermoplastic prepreg intermediate material at a temperature higher than the melting point of the hydrophobic thermoplastic resin film. A fuel cell separation membrane manufactured using the thermoplastic prepreg intermediate material and thermoplastic prepreg is thin and light-weight, and have a good durability.

Provided is a sheet press molding method by which a molded product having a small plate thickness deviation is obtained. Such a sheet press molding method is provided with a process in which a molded product (30) having a recess and protrusion pattern portion (32), to which a recess and protrusion pattern (3) is transferred, is formed by pressurizing a sheet-shaped material (20) including 60 vol. % to 95 vol. % of a filler and a resin composition using a pair of molds (40) having the predetermined recess and protrusion pattern (3) composed of recessed portions (3a, 3b, and 3c) and protrusion portions (23a, 23b, 23c, and 23d) in at least one of a pair of the molds, in which the mold provided with a dummy pattern (24) composed of dummy protrusion portions (24a) that offset the difference between the total volume of the protrusion portions (23a, 23b, 23c, and 23d) formed on the inside (14) and the total volume of the recessed portions (3a, 3b, and 3c) disposed between the protruding portions (23a, 23b, 23c, and 23d) and the side surfaces (14b) of the inside (14) and the recessed portions (3a, 3b, and 3c) disposed between the protruding portions (23a, 23b, 23c, and 23d) on the inside (14) is used as a pair of the molds (40).

Provided is a sheet press molding method by which a molded product having a small plate thickness deviation is obtained. Such a sheet press molding method is provided with a process in which a molded product (30) having a recess and protrusion pattern portion (32), to which a recess and protrusion pattern (3) is transferred, is formed by pressurizing a sheet-shaped material (20) including 60 vol. % to 95 vol. % of a filler and a resin composition using a pair of molds (40) having the predetermined recess and protrusion pattern (3) composed of recessed portions (3a, 3b, and 3c) and protrusion portions (23a, 23b, 23c, and 23d) in at least one of a pair of the molds, in which the mold provided with a dummy pattern (24) composed of dummy protrusion portions (24a) that offset the difference between the total volume of the protrusion portions (23a, 23b, 23c, and 23d) formed on the inside (14) and the total volume of the recessed portions (3a, 3b, and 3c) disposed between the protruding portions (23a, 23b, 23c, and 23d) and the side surfaces (14b) of the inside (14) and the recessed portions (3a, 3b, and 3c) disposed between the protruding portions (23a, 23b, 23c, and 23d) on the inside (14) is used as a pair of the molds (40).

A fuel cell bipolar flow field plate and a fuel cell stack are provided. The fuel cell bipolar flow field plate includes a first gas channel and a second gas channel. Each of the gas channels has several sub-channels, each of the sub-channels has bending parts, and adjacent sub-channels have opposite flow directions. The sub-channels of the two gas channels form a four-leaf clover type pattern in a reaction area of the fuel cell bipolar flow field plate. A bending angle of each of the bending parts in the four-leaf clover type pattern is within 90 degrees.

A fuel cell bipolar flow field plate and a fuel cell stack are provided. The fuel cell bipolar flow field plate includes a first gas channel and a second gas channel. Each of the gas channels has several sub-channels, each of the sub-channels has bending parts, and adjacent sub-channels have opposite flow directions. The sub-channels of the two gas channels form a four-leaf clover type pattern in a reaction area of the fuel cell bipolar flow field plate. A bending angle of each of the bending parts in the four-leaf clover type pattern is within 90 degrees.

A redox flow battery stack cell frame comprising a support frame and a monolithic bipolar plate integrated within the support frame is disclosed. The bipolar plate comprises a plurality of interdigitated flow channels on at least one surface. The support frame comprises an inlet manifold formed into a facing surface of the first side of the frame, the inlet manifold comprising fluid inlet distribution channels in a serpentine arrangement, each fluid inlet distribution channel aligned with a single inlet flow channel of the bipolar plate; and an outlet manifold formed into the facing surface of the opposing side of the frame, the outlet manifold comprising fluid outlet distribution channels in a serpentine arrangement, each fluid outlet distribution channel aligned with a single outlet flow channel of the bipolar plate. Redox flow battery stack cells and stacks comprising the stack cell frame are also disclosed.

A flow battery includes an electrochemical cell that has a first electrode, a second electrode spaced apart from the first electrode, and a separator layer arranged between the first electrode and the second electrode. The separator layer is formed of a polymer that has a polymer backbone with cyclic groups that are free of unsaturated nitrogen and one or more polar groups bonded between the cyclic groups.