Anode Temperature Control System Design Of Passive Micro Direct Methanol Fuel Cell

Characteristics of micro direct methanol fuel cells, high energy density,no-pollution, fast response, making it becoming the first power supplyfor future portable electronics. The passive micro direct methanol fuel cell is more suitable for portable power source due to its work principle: without outside energy-consuming equipment. Currently researches show that: the passive fuel cell exports low output voltage; and the temperature has a significant effect on the output characteristics of the fuel cell. Therefore, design of passive micro direct methanol fuel cell based on the temperature control system is critical.Firstly, the two-dimensional fuel cell model of passive micro direct methanol fuel cell is established to analyze the effect of temperature characteristics. Model coupled with the momentum transfer equation, mass transfer equations, temperature transfer equation, the current conduction equation and electrochemical reaction equation. Methanol transport, the anode pressure and cathode saturation are investigated under different operating temperature. Simulation results show that: the improvement of operating temperature can increase the methanol concentration oncatalyst layer, increasing the anode pressure, reduce the cathode liquid saturation, these factors can enhance the cell performance. The results can provide a theoretical basis for the experimental analysisoftemperature characteristics and passive μDMFCsystem.The temperature experimental investigation are conducted after simulation. The optimal operating condition of passive μDMFCis working concentration of2mol/L and operating temperature of60℃. The results showed that: the increase of temperatures can increase methanol diffusion coefficient and improve the catalyst activity, and then enhances the cell performance.Conventional fuel cell heating systems decreases the μDMFCenergy efficiency seriously. Based on the theoretical analysis, in this paper, micro direct methanol fuel cell patterned with an adaptive thermal control systemisdesigned. Heating method coupled with the microcontroller and relay jointly controlled heating film. This method combines the factor that the process of cell working will release heat. This method improves the efficiency and the net power output of theμDMFC.The performance of μDMFCwith and without temperature control system is tested. The result indicates that μDMFCwith temperature control system has been significantly improved performance, energy efficiency, Faraday efficiency and fuel utilization. The power density with temperature control system is2.5times than that without temperature system. The Faraday efficiency and energy efficiency are31.69％,29.03％ and9.33％,4.28％. The system power is calculated and analyzed: thepowerof improved fuel cell minus thermal control system is much larger than conventional fuel cell power output under the same size. Verify the effectiveness of the design of the temperature control system.