Fuel cell system bleeder circuit based on two-stage protection

Abstract

The invention relates to the technical field of fuel cells, and especially relates to a fuel cell system bleeder circuit based on two-stage protection. The circuit comprises a fuel cell stack, a fuelcell boost DCDC module, a finished automobile high-voltage power distribution box PDU and a bleeding heater, the fuel cell boost DCDC module comprises a DCDC boost circuit, a DCDC input side main relay K2 and a DCDC output side main relay K5, the output end of the fuel cell stack is connected with the DCDC boost circuit through the K2; the DCDC boost circuit is connected with the input end of thefinished automobile high-voltage power distribution box PDU through the K5, the fuel cell boost DCDC module comprises a discharge relay K3 and a PTC power supply relay K7, the output end of the fuel cell stack is connected with the input end of the bleeding heater through the K3, and the K5 is connected with the input end of the bleading heater through the K7. A traditional bleeder resistor is omitted, a load PTC heater is directly utilized, and the boost DCDC space and cost are saved. And meanwhile, the requirement for rapid bleeding can be met, and the emergency shutdown time of a fuel cellsystem is saved.

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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