Fuel cell system discharge circuit based on two-level protection

Abstract

The invention relates to the technical field of fuel cells, in particular to a fuel cell system discharge circuit based on two-level protection. Including fuel cell stack, fuel cell step-up DCDC module, vehicle high-voltage power distribution box PDU and discharge heater, fuel cell step-up DCDC module includes DCDC step-up circuit, DCDC input side main relay K2 and DCDC output side main relay K5 , the fuel cell stack output terminal is connected to the DCDC boost circuit through K2, and the DCDC boost circuit is connected to the vehicle high-voltage power distribution box PDU input terminal through K5. The fuel cell boost DCDC module includes a discharge relay K3 and a PTC power supply relay K7. The output end of the stack is connected to the input end of the discharge heater through K3, and K5 is connected to the input end of the discharge heater through K7. The traditional bleed resistor is canceled, and the load PTC heater is directly used, which saves the space and cost of boosting DCDC. At the same time, it can meet the requirements of quick release and save the emergency shutdown time of the fuel cell system.

Description

technical field [0001] The invention relates to the technical field of fuel cells, in particular to a fuel cell system discharge circuit based on two-level protection. Background technique [0002] With the continuous development of fuel cell technology, fuel cell vehicles have become the main trend of domestic development. At present, the domestic and foreign markets of hydrogen fuel cell vehicles are mainly based on the "electric-electric hybrid" model, that is, a hybrid model in which the fuel cell is the mainstay and the power battery is the auxiliary. As the domestic fuel cell technology has just started, the main components still need to be imported, so the cost is high. [0003] At present, the service life of domestic mainstream fuel cells is about 3000H, and some are even shorter. Therefore, it is particularly important to improve the service life of fuel cells, especially the protection design of fuel cell stacks has become the industry's first concern. After the...

AI Technical Summary

Problems solved by technology

[0004] like figure 1 , the traditional gas-fired system discharge circuit is simple, and the pure resistance is used for discharge, and the discharge strategy is relatively simple, which cannot play a good role in protecting the electric stack.

In addition, it uses resistors in series with relays for discharge, which generally reduces the output voltage of the fuel stack to below 60V, and the resistance is 500Ω / 200W, which results in low discharge efficiency and takes a long time

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