摘要:
One aspect of the invention includes the discovery that pinholes in the membrane of the membrane electrode assembly may be caused by hygroexpansive ratcheting. In one embodiment of the invention, a fuel cell stack including a plurality of cells each having a membrane electrode assembly each including a membrane manufactured by an extrusion method and operated so that the rate of drying during humidity cycling is sufficiently low to reduce or eliminate build up stresses in the membrane electrode assembly.
摘要:
The present invention is directed to addressing performance issues attributable to membrane electrode assemblies, and the components thereof, in electrochemical conversion cells. In accordance with one embodiment of the present invention, a device comprising at least one electrochemical conversion cell is provided. The cell is configured to convert first and second reactants to electrical energy and comprises a membrane electrode assembly and at least one membrane reinforcement layer. The combination of elastic modulus and thickness of the reinforcement layer and the bond between the reinforcement layer and the membrane electrode assembly are sufficient to enhance the structural integrity of the membrane electrode assembly beyond the operational degradation threshold of the assembly.
摘要:
A device configured to convert a hydrogenous fuel source to electrical energy is provided, the device comprising an electrochemical conversion assembly compressively loaded along a loading axis of the conversion assembly and at least one side plate. The side plate includes a proximal end, a distal end, and at least one spring element positioned between the proximal end and the distal end. The spring element is configured to maintain the compressive loading along the loading axis of the electrochemical conversion assembly. The device can further comprise a fuel cell, and the device can further comprises structure defining a vehicle powered by the fuel cell.
摘要:
One aspect of the invention includes the discovery that pinholes in the membrane of the membrane electrode assembly may be caused by hygroexpansive ratcheting. In one embodiment of the invention, a fuel cell stack including a plurality of cells each having a membrane electrode assembly each including a membrane manufactured by an extrusion method and operated so that the rate of drying during humidity cycling is sufficiently low to reduce or eliminate build up stresses in the membrane electrode assembly.
摘要:
A fuel cell system is provided including a fuel cell stack having a first end and second end, the stack comprising at least one fuel cell, a first end unit disposed adjacent the first end of the fuel cell stack, a second end unit disposed adjacent the second end of the fuel cell stack, and a compression retention system. The compression retention system includes at least one generally planar strip forming at least one bend, wherein the at least one strip extends from the first end unit to the second end unit of the fuel cell system. The at least one bend of the planar strip can form at least one serpentine shape.
摘要:
The present invention is directed to addressing performance issues attributable to membrane electrode assemblies, and the components thereof, in electrochemical conversion cells. In accordance with one embodiment of the present invention, a device comprising at least one electrochemical conversion cell is provided. The cell is configured to convert first and second reactants to electrical energy and comprises a membrane electrode assembly and at least one membrane reinforcement layer. The combination of elastic modulus and thickness of the reinforcement layer and the bond between the reinforcement layer and the membrane electrode assembly are sufficient to enhance the structural integrity of the membrane electrode assembly beyond the operational degradation threshold of the assembly.
摘要:
Methods of producing an electrochemical conversion assembly comprising an electrochemical conversion cell are provided. The electrochemical conversion cells which comprises a membrane electrode assembly, first and second flowfield portions defined on opposite sides of the membrane electrode assembly, and, at least one vapor barrier layer disposed between the membrane electrode assembly and at least one of the flowfield portions. The method further includes selecting a desired mass transfer coefficient MTC for the at least one vapor barrier layer of at least about 0.05 cm and optimizing one or more of the porosity, the tortuosity, and the thickness of the vapor barrier layer to produce the desired MTC in the vapor barrier layer.
摘要:
Arrays of fiber pigtails can be used to project and receive light. Unfortunately, most fiber pigtail arrays are not aligned well enough for coherently combining different optical beams. This imprecision stems in part from misalignment between the optical fiber and the endcap spliced to the end of the optical fiber. The endcap is often polished, curved, or patterned, causing the light emitted by the endcapped fiber to refract or diffract as it exits the endcap. This refraction or diffraction shifts the apparent position of the beam waist from its actual position. Measuring this virtual beam waist position before and after splicing the endcap to the fiber increases the absolute precision with which the fiber is aligned to the endcap. This increase in absolute precision reduces the deviation in virtual beam waist position among endcapped fibers, making it easier to produce arrays of endcapped fibers aligned precisely enough for coherent beam combining.
摘要:
Embodiments are described for reducing common-mode current in electronic devices. In the various embodiments, a resonant converter is employed, for example in a power supply, and the resonant converter is driven by a DC input to generate an AC primary voltage on the primary windings of a power transformer. The DC input may be derived from an AC line voltage or a DC-to-DC converter. The AC primary voltage drives the primary winding of the transformer to generate an AC secondary voltage on at least one secondary winding of the transformer. The AC secondary voltage may then drive a rectifier, which in turn drives a low-pass filter to produce a DC output voltage. Phase-shift modulation is employed which, in conjunction with the resonant converter, applies a sinusoidal waveform to the primary of the transformer resulting in a reduced amount of common-mode current injected onto the secondary.
摘要:
A planetary gear assembly includes a sun gear, planetary gears engaging the sun gear, a ring gear arranged about the planetary gears, the ring gear engaging the planetary gears, and a carrier frame including one or more pairs of bearing containment bands, a plurality of connecting segments, a plurality of spoke portions, and a hub portion, wherein each pair of bearing containment bands is connected to an adjacent pair of bearing containment bands with a connecting segment of the plurality of connecting segments and a spoke portion of the plurality of spoke portions connects each connecting segment to the hub portion.