Degradation mechanisms of proton exchange membrane fuel cell under typical automotive operating conditions

Experimental study on different preheating methods for the cold-start of PEMFC stacks

Freezing of Biologicals Revisited: Scale, Stability, Excipients, and Degradation Stresses.

Degradations in porous components of a proton exchange membrane fuel cell under freeze-thaw cycles: Morphology and microstructure effects

In the current research, the energy, exergy, environmental and economic (4E) analyzes of a PEM fuel cell are investigated. Parameters related to exergy are studied by considering the environmental effects and operating conditions of the PEM fuel cell. Multi-objective optimization is applied to maximize output power and efficiency and minimize environmental impacts and cost. The fuel cell is simulated with coolant channels and the effects of using porous metal foam inside the gas channels and coolant channels are investigated on the distribution of hydrogen and liquid water. The effect of using a hybrid nanofluid as a high potential liquid to keep the fuel cell cool is investigated. Optimal output power and optimal cost are provided according to the number of different cells. Optimal efficiencies (energy and exergy) and optimal environmental characteristics are likewise presented in a wide range of current densities. The results show that the simultaneous use of nanofluid and porous metal foam for cooling the fuel cell may not be appropriate. Furthermore, the effect of using metal foam is recommended for better cooling (increased heat transfer) of the fuel cell. Likewise, the use of porous metal foam inside the anode channel affects the distribution of hydrogen and liquid water. The effect of using porous foam in Re = 300 and above is significant so that in Re = 300, a 48% increase in heat transfer compared to the channel without porous foam can be seen. Besides, the percentage of reduction of nanofluid heat transfer in the presence of porous foam (in Re = 500) compared to pure water is 7.5%. 

Energy, exergy, environmental and economic analyzes (4E) and multi-objective optimization of a PEM fuel cell equipped with coolant channels

Numerical analysis of ice-induced stresses in the membrane electrode assembly of a PEM fuel cell under sub-freezing operating conditions

The invention discloses a partition test system of the cold start current density and temperature of a fuel cell A fuel cell system comprises a fuel cell, a thermocouple, an ice bath, an air intake system module, a high and low temperature alternating box, a cooling tube, a data acquisition module, a data processing module, and a load The test method comprises the steps that: a current density test board is placed at an anode; both the cathode flow field plate and the cathode end plate have jacks, and the thermocouple is placed in the jack; the ice bath provides cold junction compensation for the thermocouple; the temperature in the high and low temperature alternating box is set to be the ambient temperature of the cold start; the intake system module supplies the fuel cell with oxidantand fuel and is connected to the load to make it work normally; the data acquisition module collects the voltage of the sampling resistor and the thermoelectric potential of the thermocouple The data processing module converts the collected signal into a current density distribution map and a temperature distribution map at each moment of the fuel cell Compared with the prior art, the inventionhas the advantages of low manufacturing cost, accurate measurement, simple structure and the like

Partition test system and method of cold start current density and temperature of fuel cell

The invention discloses a fuel battery low-temperature starting grading preheating control method. According to the fuel battery low-temperature starting grading preheating control method, an electric pile, a sensor for measuring the temperature of the electric pile, a fuel supply system, an oxidizing agent supply system, a cooling medium circulating medium, an electric pile power output circuit, an external heat source heating system, an internal heat source heating system and a total control system are provided, wherein the external heat source heating system utilizes a mode of directly heating the electric pile by an electric heating wire, or a mode of circularly heating the electric pile after a cooling medium is heated or a mode of heating the electric pile after the air is heated; and the internal heat source heating system utilizes heat generated by electrochemical reaction of the electric pile or heat generated by catalytic combustion in the electric pile. According to the method, the preheating mode of the electric pile is determined based on a change relation between supercooling degree and the induction time of liquid water icing influenced by a porous medium material component and a microporous structure and according to the environment temperature of fuel batter low-temperature starting, safe, rapid and efficient starting of the electric pile is guaranteed, and the durability of the electric pile is improved.

Fuel battery low-temperature starting grading preheating control method

The invention discloses a PEM electric pile with a cold start different-stage preheating mode, and a system. The PEM electric pile is divided into three assemblies by thermal isolation structures, wherein the first assembly comprises a bipolar plate and an MEA assembly; the second assembly comprises end plates, an insulating plate and a collector plate assembly; the third assembly comprises a cooling medium and a pipeline and equipment; the thermal isolation structures comprise a thermal isolation structure arranged on the inner wall of a fuel supply system, a thermal isolation structure arranged on the inner wall of a cooling medium circulation system, and a thermal isolation structure arranged on the inner wall of an oxidizing agent supply system and a thermal insulation plate; the end plates are positioned on the two sides of the electric pile, and inlet-outlet channels of the fuel supply system, the oxidizing agent supply system and cooling medium circulation system are formed in the end plates; the insulating plate is positioned between the end plates and the thermal insulation plate; a groove is formed in one side close to the thermal insulation plate, and the thermal insulation plate is placed in the groove; the thermal insulation plate is positioned in the insulating plate groove for isolating the first assembly and the second assembly; a groove is formed in one side close to the collector plate, and the collector plate is arranged in the groove; and the collector plate is embedded in the insulating plate groove.

PEM electric pile with cold start different-stage preheating mode, and system

The invention discloses a PEM battery flow field plate with a helical structure channel. The PEM battery flow field plate comprises battery channels arranged on a bipolar plate; the battery channels comprise an inlet channel provided with an inlet, an outlet channel provided with an outlet and at least one branch channel, the inlet of every branch channel communicates with the inlet channel, and the outlet of every branch channel communicates with the outlet channel; and the at least one branch channel is a branch channel having a helical structure. The special rotating structure makes a gas effectively diffuse to the ridge part among the channels and carry water aggregated below or nearby ridges into the channels in order to discharge the water and promote the water discharging effect, so water generated by a cathode can be rapidly discharged through the channels and reaches the outlet in order to effectively prevent or alleviate cathode flooding; and the increase of the reaction gas utilization rate and the increase of the water conveying rate make the comprehensive performances of a PEM improved.

Zhao Hualiang

Papers

Numerical analysis of ice-induced stresses in the membrane electrode assembly of a PEM fuel cell under sub-freezing operating conditions

Partition test system and method of cold start current density and temperature of fuel cell

Fuel battery low-temperature starting grading preheating control method

PEM electric pile with cold start different-stage preheating mode, and system

PEM battery flow field plate with helical structure channel