Fuel cell low-temperature starting system and control method

Abstract

The invention discloses a fuel cell low-temperature starting system and a control method, the fuel cell low-temperature starting system comprises a fuel cell stack, a thermal management controller, an air system and a cooling liquid circulation system, the thermal management controller is in communication connection with the air system and the cooling liquid circulation system respectively, and the air system and the cooling liquid circulation system are connected with the fuel cell stack respectively. The air system is connected with the cooling liquid circulating system; the cooling liquid circulating system comprises a water pump, a three-way electromagnetic valve, a phase change heat reservoir, a thermostat, a radiator and a temperature sensor; the air system comprises an air compressor, a three-way electromagnetic valve, an intercooler and a humidifier. Extra energy consumption required by preheating modes such as electric heating or hydrogen catalytic combustion and the like which are usually adopted by the fuel cell during low-temperature starting is avoided, the utilization rate of vehicle-mounted energy of a fuel cell automobile is improved, and the driving range of the fuel cell is prolonged; and meanwhile, the problem of icing of the catalyst layer in the low-temperature starting process is also relieved, and the durability of the membrane electrode of the fuel cell is improved.

Description

technical field [0001] The invention relates to the technical field of thermal management of fuel cell power systems, in particular to a fuel cell low temperature start-up system and a control method. Background technique [0002] With the increasingly prominent environmental and energy issues, the development of new energy vehicles has become a global consensus. As one of the solutions for vehicle electrification, in addition to the advantages of pure electric vehicles compared to fuel vehicles, fuel cell vehicles also have the characteristics of long cruising range and short charging time. final goal. [0003] At present, the large-scale commercialization of fuel cell vehicles still has problems such as high cost, short lifespan, and weak hydrogen infrastructure. Among them, the low temperature startup of fuel cells is one of the key technical bottlenecks hindering the commercialization of fuel cells, and it is the biggest challenge for fuel cell vehicles to operate in w...

AI Technical Summary

Problems solved by technology

[0004] When the fuel cell is started in a low temperature environment below 0°C without taking any protective measures, the water produced by the reaction will first freeze inside the catalytic layer, resulting in the covering of the active sites of the catalytic layer and the transmission of oxygen. Blocked, the voltage drops suddenly; when the catalytic layer is completely covered by ice and the stack temperature has not risen above 0°C, ice will form in the diffusion layer and flow channel, resulting in cold start failure

On the other hand, the freezing process of the catalytic layer can lead to gaps between the catalytic layer and the proton exchange membrane, while the freezing / thawing cycle can cause the collapse and densification of the microporous structure of the catalytic layer and the coarsening of platinum particles in the catalytic layer. , causing the electrochemically active surface area to decrease and be difficult to recover, thus causing permanent damage to the power generation performance of the fuel cell, and the more cycles, the lower the cold start temperature, the greater the damage to the battery

[0005] At present, the solution strategies for low-temperature start-up of fuel cells are divided into two categories: one is to use gas purging to reduce the water content of fuel cell membrane electrodes when the stack is shut down, thereby reducing the formation of solid ice, but when the stack temperature does not rise to When the temperature is above 0°C, as long as the electric stack is started to generate water, it will freeze, and firstly, ice will be formed on the part where the surface of the platinum particle contacts with Nafion resin. Once the temperature rises to room temperature, the ice at the interface between platinum and Nafion will melt and cause the interface to detach. lead to irreversible loss of electrochemically active area; the other is to preheat the stack and its internal plates and membrane electrodes by means of electric heating of the configured power battery or hydrogen catalytic combustion. The problem is that it needs to consume more energy (vehicle electric energy or hydrogen energy), which shortens the cruising range of fuel cell vehicles

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