【摘要】：質(zhì)子交換膜燃料電池(PEMFC)是適用于汽車，備用電源和便攜式電源的能量轉(zhuǎn)換裝置。膜電極組件(membrane electrode assembly, MEA)是PEM燃料電池中關鍵部件之一，包含CL(CL)，質(zhì)子交換膜(PEM)，GDL(GDL)，邊框及密封部件。影響PEM燃料電池得到廣泛應用的一個工程挑戰(zhàn)就是膜電極裝配及其引起的水傳輸問題。本論文通過模擬和實驗從機理上對這一問題進行分析討論。 (1)通過有限元模型首次分析了MEA中的邊框材料，結(jié)構(gòu)以及接觸行為在組裝過程對膜的應力影響。在膜與邊框交界區(qū)域存在嚴重的應力分布不均。相比于齊邊框組裝，臺階式邊框結(jié)合粘貼綁定接觸行為組裝時在膜上的應力分布更加均勻些。對于臺階式邊框，邊框材料不再是影響應力分布不均的主要因素；對于齊邊框組裝，為使膜上的應力分布均勻化，邊框材料的機械特性應與膜相似。 (2)運用多電極探針法區(qū)分出CL，，GDL和BPP的體電阻(bulk resistances)和面電阻(contact resistances)。比較了碳CL，碳紙和碳布GDL材料和微孔層(MPL)的電阻。碳CL電阻是碳紙GDL體電阻的100倍以上。碳紙的體電阻和面電阻是碳布GDL的一半。對GDL進行壓縮能夠降低GDL面電阻，但是對體電阻基本無影響。對GDL進行疏水處理增加了面電阻，但是體電阻幾乎無變化。MPL的添加能夠顯著減小面電阻，但是對體電阻基本無影響。根據(jù)實驗建立了一個等效回路模型，并顯示當流道寬度小于1mm時，電池電子電阻可忽略不計。面電阻是電池中主要的電子電阻，并占整個歐姆電阻的8%。 (3)通過實驗模擬分析陰極CL產(chǎn)生的水穿過GDL材料到達氣體流道的路徑和阻力。水的傳輸路徑分為橫向傳輸(在GDL與CL之間的界面?zhèn)鬏?和縱向傳輸(在GDL中的大孔徑中傳輸)。在縱向傳輸過程中，GDL中最大孔中的小孔徑是限制水滲透的主要阻力。當水頭壓力足夠大時，水才能進入并且穿過這些限制孔徑。水在這些孔中流動時所需壓力要小于水初始穿透這些孔所需壓力。當GDL的壓縮率小于20%，液態(tài)水在界面處的橫向傳輸阻力小于液態(tài)水穿透GDL的阻力。 (4)考察在不同的雷洛數(shù)和GDL壓縮率下，水在帶有彎道的單流道中的流動特性。氣體能夠從脊岸下的GDL中旁通到流道下游部分，同時也能從小水柱下的GDL中傳輸。根據(jù)實驗結(jié)果，GDL中的水出口與流道彎道之間的距離d與對應的氣體流量比應大于13%。在一個壁面為疏水性的多孔GDL材料，另三個為親水性的亞克力壁面的矩形流道中，小水柱的形態(tài)為倒梯形。增加GDL壓縮率有利于水的排出。與圓弧型彎道相比，殘余液滴更容易掛在直角彎道處。在不同雷洛數(shù)下，流道中水的流動形態(tài)分為小水柱流動，液滴受擠壓流動，拉長與收縮式移動，振動移動以及小液滴移動。 (5)通過實驗分析受壓縮的GDL對氣體旁通以及小水柱在平行流道中流動的影響。小水柱堵塞氣體流道的橫截面使得氣體從小水柱下的GDL中流通或者從脊岸下的GDL中流通。氣體在流道之間流通使得平行流道中的小水柱出現(xiàn)同步移動現(xiàn)象。氣體在GDL中流通依賴于GDL的滲透率，而GDL滲透率是通過燃料電池組裝時對GDL的壓縮量決定的。分析了在一壁面為壓縮GDL的平行流道中小水柱和氣體旁通的流動特性。平行流道下的GDL通過脊岸受到壓縮與燃料電池中BPP壓縮GDL一致。根據(jù)實驗結(jié)果，建立了氣體在流道和GDL中的流動物理模型。此模型顯示氣體在相鄰流道下的GDL中流通引起小水柱同步移動。通過設置實驗程序，通過小水柱的體積和其越過相鄰流道中的障礙水柱的距離可以確定流道下GDL的滲透率以及脊岸下GDL的滲透率。
[Abstract]:The proton exchange membrane fuel cell (PEMFC) is an energy conversion device suitable for use in an automobile, a standby power supply, and a portable power source. Membrane electrode assembly (MEA) is one of the key components in PEM fuel cell, including CL (CL), proton exchange membrane (PEM), GDL (GDL), frame and sealing component. One of the engineering challenges that affect the wide application of PEM fuel cells is the assembly of membrane electrodes and the water transport problems caused by membrane electrode assembly. This paper makes an analysis and discussion on this problem from the mechanism of simulation and experiment. (1) The stress shadow of the membrane during the assembly process is analyzed for the first time by the finite element model. in response to that presence of a severe stress distribution at the interface region of the film and the frame None. The stress distribution on the membrane is even more uniform when the stepped frame is assembled in combination with the binding contact behavior than the alignment frame assembly For the stepped frame, the frame material is no longer the main factor that affects the non-uniformity of the stress distribution; for the assembly of the alignment frame, the mechanical characteristics of the frame material shall be the same as that of the film phase, so that the stress distribution on the film is uniform. (2) The bulk resistance and the contact resistance of the CL, GDL and BPP are distinguished by the multi-electrode probe method. es). The carbon CL, the carbon paper and the carbon cloth GDL material and the microporous layer (MPL) are compared The resistance of the carbon CL resistor is 100% of the resistance of the carbon paper GDL body The body resistance and the surface resistance of the carbon paper are carbon cloth GDL. Half of the GDL compression reduces the GDL face resistance, but the body resistance is essentially No effect. The surface resistance is increased by the hydrophobic treatment of the GDL, but the bulk resistance is almost No change. The addition of MPL can significantly reduce the surface resistance, but the body resistance is essentially There is no effect. An equivalent circuit model is established according to the experiment, and when the width of the flow channel is less than 1 mm, the electronic resistance of the battery can be ignored. The surface resistance is the main electrical resistance in the battery, and it accounts for the total ohmic resistance and (3) analyzing the water generated by the cathode CL through the experimental simulation to reach the gas flow channel through the GDL material, Path and resistance. The transmission path of water is divided into transverse transmission (interface transfer between GDL and CL) and longitudinal transmission (large hole in GDL In the longitudinal direction, the small pore size in the largest hole in the GDL is to limit water penetration. The main drag is that water can enter and pass through this when the head pressure is large enough some limiting apertures. The pressure required for water to flow in these holes is less than the initial penetration of water The required pressure of the hole. When the compression ratio of the GDL is less than 20%, the lateral transfer resistance of liquid water at the interface is less than the liquid water penetration G. The resistance of the DL. (4) The water is examined at different LROs and GDL compression rates and water flows in a single stream with a curve The flow characteristics in the channel. The gas can be bypassed from the GDL in the back of the ridge to the downstream part of the flow channel, and can also be removed from the small water column according to the experimental results, the distance d between the water outlet and the flow channel curve in the GDL and the corresponding gas flow rate The ratio should be more than 13%. In a porous GDL material that is hydrophobic in one wall, the other three is a rectangular flow path of the hydrophilic acrylic wall, and the small water column And the shape of the GDL compression ratio is increased. Is beneficial to the discharge of water, and the residual liquid drops can be more easily compared with the arc-shaped curve. the flow of the water in the flow channel is divided into small water column flow under the different oredotes, and the liquid drops are subjected to extrusion flow, elongation and contraction movement, vibration movement, and (5) analyzing and analyzing the compressed GDL to bypass the gas and the small water column to be flat, the effect of flow in a flow channel. the cross-section of the small water column blocking the gas flow channel allows the gas to flow through or from the gdl under the small water column the flow of gas in the gdl under the shore. the flow of gas between the flow channels allows for small water in the parallel flow path the column presents a synchronous movement phenomenon. the flow of gas in the gdl depends on the permeability of the gdl and the gdl permeability is for g when the fuel cell is assembled, The compression amount of the DL is determined. The small water column and the small water column in the parallel flow path of the compressed GDL on a wall surface are analyzed. The flow characteristics of the gas bypass. The GDL under the parallel flow channel is compressed in the fuel cell through the ridge The PP compression GDL is consistent. According to the experimental results, the gas is established in the flow channel and the GD. Flow physical model in L. This model shows the flow of gas in the GDL under adjacent flow channels The permeability of the GDL under the flow channel and the ridge can be determined by setting the experimental procedure, by setting the volume of the small water column and the distance of the small water column across the barrier water column in the adjacent flow path.
【學位授予單位】：武漢理工大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TM911.4

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相關期刊論文 前2條

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2 李文安;楊立軍;杜小澤;楊勇平;;陽極加濕對質(zhì)子交換膜燃料電池性能的影響[J];中國電機工程學報;2010年17期

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