Low-temperature start control method for fuel cell system

Abstract

The invention discloses a low-temperature start control method for a fuel cell system. The low-temperature start control method comprises parking control and start control. According to the invention, when parking control is carried out, a fuel cell is kept in relatively high reaction gas supply quantity; therefore, a role of blowing is played; residual liquid water in the fuel cell can be removed; simultaneously, the fuel cell is kept in relatively low intermittent loading current; intermittent water supply to a proton exchange membrane of the fuel cell can be carried out, such that the excessive water loss condition of the proton exchange membrane is prevented; when the fuel cell system is started, the fuel cell releases heat to increase the temperature by utilizing self reaction; an extra auxiliary energy is unnecessary to heat; furthermore, loading start is carried out by adopting the starting condition and the current density corresponding to a parking post-treatment process; the low-temperature start process of the fuel cell system can be successfully implemented; due to the invention, the fuel cell can be controlled in a proper state after parking in a low-temperature temperature; and furthermore, the fuel cell system can be rapidly started again in the state in the low-temperature temperature.

Description

technical field [0001] The present invention relates to the technical field of proton exchange membrane fuel cells, and more specifically to a control method for a fuel cell system that can realize low-temperature start-up Background technique [0002] Proton exchange membrane fuel cells (hereinafter referred to as fuel cells) use hydrogen and air (or oxygen) as reaction raw materials, generate product water and release heat in the process of external energy supply. As an efficient and clean energy conversion device, fuel cells are used in vehicle power systems and need to meet the application requirements of adapting to low temperature environments. The fuel cell generates product water during operation, and its proton exchange membrane needs to ensure a certain water content to realize its internal proton conduction process. Therefore, when the fuel cell is applied in a low temperature environment (below 0°C), when it is stopped and restarted, it faces the problem of how ...

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Problems solved by technology

[0004] The low-temperature start-up devices and methods provided by the above-mentioned patents are all low-temperature start-ups realized in the presence of auxiliary power sources or heating components. The disadvantage of the above-mentioned methods is that the components for auxiliary start-up are added, and the complexity of the fuel cell system is also increased. At the same time, the additional power supply and heating components also increase the auxiliary energy consumption of the fuel cell system during the low-temperature start-up process, that is, the method provided is not the unassisted low-temperature start-up achieved by using the self-heating of the stack, and the method lacks the ability to control the fuel cell system after shutdown. Control of the post-processing process

It should be noted that the battery needs to realize unassisted self-starting in a low temperature environment. Not only does it need to design the fuel cell system and the control method of the starting process, but also the processing process of the last stop before starting is also very important. The above-mentioned patent provides In the method, there is no corresponding low-temperature parking method, and in the actual application process, there is a lack of targeted parking control methods. The low-temperature environment after parking can easily cause damage to the membrane electrode of the battery, resulting in the failure of low-temperature startup.

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