膜电极压缩引起的燃料电池内部应力、内阻及水传输行为研究
发布时间：2019-06-21 17:24
【摘要】：质子交换膜燃料电池(PEMFC)是适用于汽车，备用电源和便携式电源的能量转换装置。膜电极组件(membrane electrode assembly, MEA)是PEM燃料电池中关键部件之一，包含CL(CL)，质子交换膜(PEM)，GDL(GDL)，边框及密封部件。影响PEM燃料电池得到广泛应用的一个工程挑战就是膜电极装配及其引起的水传输问题。本论文通过模拟和实验从机理上对这一问题进行分析讨论。 (1)通过有限元模型首次分析了MEA中的边框材料，结构以及接触行为在组装过程对膜的应力影响。在膜与边框交界区域存在严重的应力分布不均。相比于齐边框组装，台阶式边框结合粘贴绑定接触行为组装时在膜上的应力分布更加均匀些。对于台阶式边框，边框材料不再是影响应力分布不均的主要因素；对于齐边框组装，为使膜上的应力分布均匀化，边框材料的机械特性应与膜相似。 (2)运用多电极探针法区分出CL，，GDL和BPP的体电阻(bulk resistances)和面电阻(contact resistances)。比较了碳CL，碳纸和碳布GDL材料和微孔层(MPL)的电阻。碳CL电阻是碳纸GDL体电阻的100倍以上。碳纸的体电阻和面电阻是碳布GDL的一半。对GDL进行压缩能够降低GDL面电阻，但是对体电阻基本无影响。对GDL进行疏水处理增加了面电阻，但是体电阻几乎无变化。MPL的添加能够显著减小面电阻，但是对体电阻基本无影响。根据实验建立了一个等效回路模型，并显示当流道宽度小于1mm时，电池电子电阻可忽略不计。面电阻是电池中主要的电子电阻，并占整个欧姆电阻的8%。 (3)通过实验模拟分析阴极CL产生的水穿过GDL材料到达气体流道的路径和阻力。水的传输路径分为横向传输(在GDL与CL之间的界面传输)和纵向传输(在GDL中的大孔径中传输)。在纵向传输过程中，GDL中最大孔中的小孔径是限制水渗透的主要阻力。当水头压力足够大时，水才能进入并且穿过这些限制孔径。水在这些孔中流动时所需压力要小于水初始穿透这些孔所需压力。当GDL的压缩率小于20%，液态水在界面处的横向传输阻力小于液态水穿透GDL的阻力。 (4)考察在不同的雷洛数和GDL压缩率下，水在带有弯道的单流道中的流动特性。气体能够从脊岸下的GDL中旁通到流道下游部分，同时也能从小水柱下的GDL中传输。根据实验结果，GDL中的水出口与流道弯道之间的距离d与对应的气体流量比应大于13%。在一个壁面为疏水性的多孔GDL材料，另三个为亲水性的亚克力壁面的矩形流道中，小水柱的形态为倒梯形。增加GDL压缩率有利于水的排出。与圆弧型弯道相比，残余液滴更容易挂在直角弯道处。在不同雷洛数下，流道中水的流动形态分为小水柱流动，液滴受挤压流动，拉长与收缩式移动，振动移动以及小液滴移动。 (5)通过实验分析受压缩的GDL对气体旁通以及小水柱在平行流道中流动的影响。小水柱堵塞气体流道的横截面使得气体从小水柱下的GDL中流通或者从脊岸下的GDL中流通。气体在流道之间流通使得平行流道中的小水柱出现同步移动现象。气体在GDL中流通依赖于GDL的渗透率，而GDL渗透率是通过燃料电池组装时对GDL的压缩量决定的。分析了在一壁面为压缩GDL的平行流道中小水柱和气体旁通的流动特性。平行流道下的GDL通过脊岸受到压缩与燃料电池中BPP压缩GDL一致。根据实验结果，建立了气体在流道和GDL中的流动物理模型。此模型显示气体在相邻流道下的GDL中流通引起小水柱同步移动。通过设置实验程序，通过小水柱的体积和其越过相邻流道中的障碍水柱的距离可以确定流道下GDL的渗透率以及脊岸下GDL的渗透率。
[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.
【学位授予单位】：武汉理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM911.4
本文编号：2504242
[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.
【学位授予单位】：武汉理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM911.4
【参考文献】
相关期刊论文 前2条
1 叶东浩;詹志刚;;PEM燃料电池双极板流场结构研究进展[J];电池工业;2010年06期
2 李文安;杨立军;杜小泽;杨勇平;;阳极加湿对质子交换膜燃料电池性能的影响[J];中国电机工程学报;2010年17期
本文编号：2504242
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