Patent Application
20090176144
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1. Field of the Invention
The present invention relates generally to a fuel cell, and more particularly to an innovative fuel cell having a bipolar plate with a phase surface of a tight structure type.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
In the structure of a common fuel cell, the bipolar plate is set at both sides of the membrane electrolyte assembly. The bipolar plate must employ highly conductive and easily processed materials. At present, common materials for a bipolar plate comprise graphite, aluminum, stainless steel, and so on. The phase surface of the bipolar plate is provided with a flow channel as the channel conducting fuel, so that the expected reaction gas (such as hydrogen and oxygen) can reach gas diffusion layer set between the bipolar plates via the channel and can get to a catalyst layer, where the electrochemical transformation reaction is aroused to generate current. With the function of current conductivity provided by the bipolar plates, the current can be conducted to a preset external loop.
It should be well understood that the phase surface between the bipolar plate and gas diffusion layer is stiff and closely attached, thus the phase surface must be processed to a extremely high degree of plainness. The required degree of airtightness of contact degree in this way, greatly increases processing costs and rates of defects, which does not conform to economic interests of the industry. Moreover, although the phase surface between the bipolar plate and gas diffusion layer reaches a required degree of plainness, when the bipolar plate of the composite set and gas diffusion layer are pressed, the fixed phase surface between the bipolar plate and gas diffusion layer may be deformed because of partial stress caused by a press point of fasteners, such as a bolt or rivet. Though the deformation degree is a very small, the gap in the phase surface between the bipolar plate and gas diffusion layer may be generated because it is a stiff surface.
Therefore, because of the different properties of conducted fuel, such as hydrogen and oxygen, the flow channels set between bipolar plates should be separated, so that the different fuels can be conducted in comparatively different directions from gas diffusion layer, following preset routes, to generate expected medical reactions. In other words, the airtight state of the phase surface between the bipolar plate and gas diffusion layer is a significant factor to determine whether nor not the channel spaces for different fuels can be assuredly separated. From this, the gaps, which are produced easily in the phase surface between bipolar plate and gas diffusion layer, will cause fuels of different properties to be mixed before they come to the gas diffusion layer. Such early mixture may result in different problems and potential risks because of a different mixture state of different fuels. To a slight extent, these problems and risks may exert negative influences on generation efficiency of fuel cells. To a serious extent, they may bring about risky explosions because of the reaction caused by direct contact of extremely plentiful fuels, such as hydrogen and oxygen, of different properties. Obviously, the matter, at present, is a crucial one which should be resolved as soon as possible in the structure of composite fuel cells of bipolar plates.
Thus, to overcome the aforementioned problems of the prior art, it would be an advancement in the art to provide an improved structure that can significantly improve efficacy.
Therefore, the inventor has provided the present invention of practicability after deliberate design and evaluation based on years of experience in the production, development and design of related products.
With innovative and unique structures, a soft airtight layer is arranged between the bipolar plate and the gasket. When compared with known structures in the prior art, it is impossible to make the combination of the bipolar plate and gasket to easily reach a steady and close state and to reduce the requirement of processing precision for the surface of the bipolar plate and gasket and decreasing the rate of defects and manufacturing costs. With the arranging of the soft airtight layer, flow channel spaces of different fuels can be definitely separated, and any leakage and mistaken mixture can be avoided, which further improves the quality of fuel cells to a great extent and practical benefits for safety.
With the structures of a hard support gasket added between the bipolar plate and soft airtight layer, a hard face shaped support can be provided for the side of the soft airtight layer facing the bipolar plate. With the capacity of preventing protrusion at the opening side in the channel of the soft airtight layer corresponding with bipolar plate, assembly quality of the fuel cell module can be further improved.
With the channel being made into a concave shape, the processing tool of the same axis can be applied to mill and shape the channel for one time in manufacturing and shaping of the channel and in processing of gas sub-channels in the bipolar plates. Manufacturing efficiency of the bipolar plate, reducing manufacturing costs, and providing more industrial use benefits are improved.
Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.
The features and the advantages of the present invention will be more readily understood upon a thoughtful deliberation of the following detailed description of a preferred embodiment of the present invention with reference to the accompanying drawings.
The fuel cell module A comprises a composite bipolar plate 10, having a gasket 20 connected thereto and a sub-channel 11 set in a side concave of the bipolar plate 10 corresponding with gasket 20. The sub-channel 11 can be snake-shaped. Moreover, main channel 31 of the first gas and main channel 32 of the second gas which run through side faces of the bipolar plate 10 are set in the separation position of the bipolar plate 10 and gas sub-channel 11. With main channel 31 and 32, different fuel reaction gases can be conducted, such as hydrogen and oxygen. The main channel 31 and 32 are connected to gas sub-channel 11 with the channel 12.
A soft airtight layer 40 is set between the bipolar plate 10 and gasket 20. The soft airtight layer 40, shown in the
Structure of the gasket 20 is shown in
The channel 12 can be concave, whose opening side is covered by soft airtight layer 40. A section of the concave channel 12 can be rectangular.
Hard support gasket 50 can be set between the bipolar plate 10 and soft airtight layer 40, being made of a thin metal sheet or thin plastic sheet. The purpose of hard support gasket 50 is to provide hard support for the side of bipolar plate 10 facing soft airtight layer 40. When the opening side of channel 12 in the side of bipolar plate 10 and a relative position of soft airtight layer 40 are mutually pressed, the opening side of channel 12 may protrude because of uneven stress on soft airtight layer 40. With the strong support of hard support gasket 50, the matter can be solved.
The composite bipolar 10 and gasket 20 can be locked and fixed through bolt 60 and nut 61, when they are connected.
With the structure of the present invention,
