Judgment method and control system for content of water generated by fuel cell

Abstract

The invention discloses a judgment method and a control system for the content of water generated by a fuel cell. The judgment method comprises the steps of: detecting the pressure values of an air inlet and an air outlet of a fuel cell stack, and obtaining the characterization value of the water content of the stack through calculation; setting a water content range for normal work of a fuel cell according to parameters of the used fuel cell, and judging a characterization value of the water content according to the water content range; and adjusting the working states of a cooling fan and an air compressor to enter a drying mode, or adjusting the working states of the cooling fan and the air compressor to enter a humidifying mode. According to the method, the drying degree of a proton exchange membrane can be accurately judged in real time in the running process of the fuel cells, the condition that the membrane is dry or flooded can be treated, water balance of the proton exchange membrane is guaranteed, and therefore high-efficiency running of the fuel cell is guaranteed.

Description

technical field [0001] The invention belongs to the technical field of fuel cells, and in particular relates to a method and a control system for judging the water content generated by fuel cells. Background technique [0002] The proton exchange membrane in the proton exchange membrane fuel cell must ensure the necessary humidity when it is working. When the fuel cell is in a short-term water failure situation, it will have a direct impact on the performance output; In a fault state, it will cause damage to the fuel cell, and these damages are generally difficult to recover. When the anode of the fuel cell is flooded, the flow and diffusion of hydrogen will be hindered, which will lead to local hydrogen depletion, and other secondary electrochemical reactions will occur in these areas, causing the carbon in the catalytic layer on the cathode side to be corroded, and corrosion occurs. Particles or impurities transported to the interior of the exchange membrane may cause bat...

AI Technical Summary

Problems solved by technology

[0002] The proton exchange membrane in the proton exchange membrane fuel cell must ensure the necessary humidity when it is working. When the fuel cell is in a short-term water failure situation, it will have a direct impact on the performance output; In the fault state, it will cause damage to the fuel cell, and these damages are generally difficult to recover

When the anode of the fuel cell is flooded, the flow and diffusion of hydrogen will be hindered, which will lead to local hydrogen depletion, and other secondary electrochemical reactions will occur in these areas, causing the carbon in the catalytic layer on the cathode side to be corroded, and corrosion occurs. Particles or impurities transported to the interior of the exchange membrane may cause battery failure

And when the membrane is flooded, it will cause voltage fluctuations, resulting in unstable output power

If the fuel cell is in a dry state for a long time, the conductivity of the proton exchange membrane will decrease, the ohmic impedance will increase, resulting in a decrease in output power, and the dry area will continue to expand until the entire area is affected, and even the exchange membrane will be damaged. Dry out and crack, causing irreparable damage to the fuel cell

[0003] At present, in the existing technology, the water level monitoring device installed is mainly used to measure the change of the water level inside the fuel cell, and to manage the water of the fuel cell, but the system structure is relatively complicated

Or by comparing the theoretical cathode pressure drop of the fuel cell obtained by the formula with the actual pressure drop, it is judged that the fuel cell is in a flooded state or a membrane dry state, and the water flooded or membrane dry state is solved by a solenoid valve or a gas-liquid separator. problem, but its theoretical cathode pressure drop is difficult to calculate accurately

Or detect the water content of the fuel cell through components such as illuminance sensors, and purge the fuel cell through the automatic flow meter and the fuel cell voltage signal to adjust the electronically controlled switch valve and regulating valve to ensure water balance, but the required sensor There are many quantities and types, and the accuracy requirements for the illuminance sensor are high

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