Separator plate for a fuel cell, precursor therefore and its method of production
AssigneeBlue World Technologies Holding Aps
InventorsDenys Gromadskyi, Larysa Hromadska
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Abstract
For production of a separator plate in a fuel cell, a malleable precursor sheet is made by mixing thermoplastic polymer, carbon fibers, and electroconductive carbon particles, which is then hot-compression molded as a single layer or multi-layer structure or multi-layer structure, where the layer thickness is less than the length of the carbon fibers.
Claims19
A separator plate for a fuel cell, wherein the separator plate is made from a moldable, malleable, precursor sheet by hot-compression molding of a single layer precursor sheet of thickness X1 into an electrically conductive, rigid single layer separator plate of thickness X2 in the range of 0.05-0.6 mm, wherein the precursor sheet and the separator plate provided as a single polymer matrix that comprises only a single thermoplastic polymer blend in which carbon fibers and electroconductive carbon particles are dispersed;
- wherein the thermoplastic polymer blend comprises polytetrafluoroethylene, PTFE, and a thermoplastic polymer different from PTFE;
- wherein the carbon fibers have an average length L that is larger than the thickness X1 of the layer, wherein L is in the range of 0.1-1 mm, wherein the weight concentration of PTFE is at least 0.05 wt. % but less than 0.5 wt. % PTFE, the weight concentration of the thermoplastic polymer different from PTFE is 5-30 wt. %, and the weight concentration of the carbon fibers is in the range of 2-20 wt. %, the weight concentrations being relatively to the total weight of the polymer blend, carbon fibers and electroconductive carbon particles.
A method of producing a separator plate by a precursor, the method comprising,
- mixing a powder of thermoplastic polymer, and a powder of carbon fibers, and electroconductive carbon particles in a dispersion to provide a thermoplastic polymer blend in which carbon fibers and electroconductive carbon particles are dispersed, wherein the carbon fibers have an average length of L in the range of 0.1-1 mm;
- wherein the thermoplastic polymer is a blend that comprises polytetrafluoroethylene, PTFE, and a second thermoplastic polymer, wherein the second thermoplastic polymer is different from PTFE;
- wherein the weight concentration of PTFE is at least 0.05 wt. % but less than 0.5 wt. % PTFE, the weight concentration of the thermoplastic polymer different from PTFE is 5-30 wt. %, and the weight concentration of the carbon fibers is in the range of 2-20 wt. %, the weight concentrations being relatively to the total weight of the polymer blend, carbon fibers and electroconductive carbon particles;
- forming a single-layer moldable malleable precursor sheet of thickness X1 from the mix by calender rolling in a forming station and causing the carbon fibers to be at least partially parallel with the slab by to the rolling;
- hot-compression molding the single-layer precursor sheet into a single layer separator plate of a thickness of X2 in the range of 0.05-0.6 mm, wherein X2 is less than the average length L of the carbon fibers, wherein L is larger than the thickness X1 of the layer and in the range of 0.1-1 mm, wherein the single layer separator plate consists of single polymer matrix that comprises only a single thermoplastic polymer blend in which carbon fibers, and electroconductive carbon particles are dispersed;
- wherein the molding is made at temperatures between melting temperatures of the PTFE and the second thermoplastic polymer.
A rigid, rolled and press-molded separator plate for a fuel cell, wherein the separator plate is formed as a single layer from a single layer precursor sheet, wherein the single layer has a thickness X2 in the range of 0.05-0.6 mm, for example 0.05-0.3 mm, and is provided as a polymer matrix that comprises a thermoplastic polymer blend in which carbon fibers and electroconductive carbon particles are dispersed;
- wherein the thermoplastic polymer blend comprises PTFE and a thermoplastic polymer different from PTFE, for example PPS;
- wherein the carbon fibers have an average length L that is in the range of 0.1-1 mm and larger than the thickness X2 of the layer;
- wherein the weight concentration of PTFE is at least 0.05 wt. % but less than 0.5 wt. % PTFE and wherein the weight concentration of the thermoplastic polymer different from PTFE, for example PPS, is 5-30 wt. %, relatively to the total weight of the polymer blend, carbon fibers and electroconductive carbon particles.
Dependencies are inferred from the claim text.