Vehicle fuel cell air system with cold start function and control method of vehicle fuel cell air system

Abstract

The invention discloses a vehicle fuel cell air system with a cold start function. The system comprises an air supply unit, a fuel cell stack and a fuel cell controller; the air supply unit is connected with the fuel cell stack; the fuel cell controller is connected with the air supply unit and the fuel cell stack; the air supply unit comprises a solid adsorption type heat storage device; the solid adsorption type heat storage device adsorbs moisture in air and releases adsorption heat used for heating the fuel cell stack to achieve cold start. The invention further discloses a control method of the vehicle fuel cell air system with the cold start function. The solid adsorption type energy storage principle is ingeniously utilized; a large amount of the adsorption heat is released in an adsorbate adsorption process through an adsorbent to preheat the fuel cell stack, so that the cold starting of the fuel cell is achieved, and the defect that the endurance mileage of a fuel cell vehicle in the prior art is shortened is overcome.

Description

technical field [0001] The invention belongs to the technical field of thermal management of a fuel cell power system, and in particular relates to a vehicle fuel cell air system with a cold start function and a control method. Background technique [0002] At present, the large-scale commercialization of fuel cell vehicles, one of the solutions for vehicle electrification, still has problems such as high cost, short lifespan, and weak hydrogen infrastructure. Among them, the cold start problem 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 winter. [0003] When the fuel cell is cold-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 release of oxygen. The tr...

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Problems solved by technology

[0003] When the fuel cell is cold-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, causing the active sites of the catalytic layer to be covered and oxygen The transmission is blocked, and the voltage drops suddenly; when the catalytic layer is completely covered by ice and the temperature of the stack 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. , resulting in the reduction of the electrochemically active surface area and it is difficult to recover, thereby 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

[0004] At present, the solutions to the cold start of fuel cells are divided into two categories: one is to use gas purging to reduce the water content of the 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 generated on the part where the surface of the platinum particle is in contact 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 vehicle-mounted power batteries or heat release of vehicle-mounted hydrogen catalytic combustion, the former will consume part of the vehicle-mounted The power of the power battery, and in the low temperature environment, the power battery also has difficulty in cold start and a large reduction in discharge capacity, the latter will consume a part of the hydrogen on the vehicle, both of which will shorten the cruising range of the fuel cell vehicle

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