Wide-range humidifying system structure of fuel cell test bench and control method of wide-range humidifying system structure

Abstract

The invention relates to a wide-range humidifying system structure of a fuel cell test board. The wide-range humidifying system structure comprises a gas supply device, a humidifying device and a control device, the gas mass flow controller is used for controlling the flow entering the humidifying system to be a stable value; the humidifying system is also provided with a humidifying system tank body, a heater, a gas distributor, a cooling heat exchanger and a demister; the method comprises the following steps: humidifying a fuel cell stack in a wide range of 0.5-10kW; dispersing dry gas required by a fuel cell reaction into uniform small bubbles by a gas distributor; the heater is used for heating water in the humidifying system tank body; the gas is uniformly humidified in the bubbling process, and water vapor with the saturation humidity of 100% RH is obtained when the gas is separated from the liquid level; when the galvanic pile needs different gas flows, galvanic pile humidification in a wide power range is realized in a liquid level and gas flow joint control mode.

Description

TECHNICAL FIELD

[0001] The present application relates to test technology and its use equipment, in particular, a fuel cell test bench wide range humidification system structure and its control method. BACKGROUND

[0002] The existing fuel cell test bench, the essence is special-purpose equipment, the applicable fuel cell power range is narrow; the physical structure and control strategy of the humidification system cannot simultaneously meet the test requirements of cross orders of magnitude from hundreds of watts to ten kilowatts, such as from 0.5kW to 10kW, with a span of 20 times: for example, a test bench designed for a 5kW stack, when dealing with the extremely low gas flow required by a 0.5kW stack, the system pressure response will be delayed due to the excessive volume of the internal container and pipeline, resulting in poor control accuracy, and even gas condensation and blockage. Conversely, if the volume of the system container and pipeline is reduced accordingly, the gas supply system may not be able to stably provide the high flow required by a 10kW stack. As a direct result, users need to purchase at least two sets of test systems, low power (such as 0.5-3kW) and medium power (such as 3-10kW), to cover the research and development requirements from 0.5kW to 10kW, resulting in a multiple increase in equipment investment, floor space and maintenance costs.

[0003] The existing fuel cell test bench, when the test power deviates from the design center point of the equipment, the control quality of the entire humidification system will decrease sharply. At very low load, such as below 10% of the rated power: the gas flow rate is too slow, resulting in uneven flow field distribution in the humidifier, with "dead zones", making the humidification uniformity poor, the temperature control unstable, causing the dew point temperature of the gas outlet to fluctuate greatly, and failing to meet the requirements of small power stacks for stable conditions. Approaching the upper limit load: the original heating power may become a bottleneck, unable to heat the high flow rate gas to the target dew point temperature, resulting in insufficient humidification capacity, affecting the accuracy of large power fuel cell stack testing.

[0004] Fuel cells face rapid and wide range dynamic load changes in actual vehicle application. Due to the inherent flow regulation range limitation of the existing narrow range humidification system, it cannot quickly and accurately provide the corresponding flow and humidity of the reaction gas when responding to extreme dynamic processes from near zero load (idling) to near full load (acceleration). Its dynamic response speed cannot keep up with the load changes, resulting in uncontrolled humidity inside the stack during the transient process - either too dry to cause the mass transfer resistance of the membrane electrode to increase sharply, or too wet to cause the stack to be flooded, thus failing to truly reflect the dynamic performance and durability of the stack.

[0005] Therefore, it is necessary to provide a fuel cell test bench wide range humidification system structure and its control method to solve the above problems. SUMMARY

[0006] The application aims to provide a fuel cell test bench wide-range humidification system structure and a control method thereof.

[0007] One of the technical solutions is as follows: A fuel cell test bench wide-range humidification system structure comprises: a gas supply device for providing dry gas with stable pressure; a gas mass flow controller for controlling the flow into the humidification system to be a stable value; and further comprises a humidification system tank, a heater, a gas distributor, a cooling heat exchanger, and a demister; The humidification system is used for humidifying a fuel cell stack in a wide range of 0.5-10 kW; The gas distributor disperses the dry gas required for the fuel cell reaction into uniform small bubbles; The heater heats the water in the humidification system tank; The gas is uniformly humidified in the bubbling process and obtains saturated humidity, i.e. 100% RH water vapor when leaving the liquid surface; When the electric pile requires different gas flow, the electric pile humidification in a wide power range is realized through the liquid level and gas volume joint control.

[0008] Further, a switch valve and a one-way valve are further provided.

[0009] Further, a pneumatic diaphragm pressure regulating valve is further provided.

[0010] Further, a spray circulating pump, a system water supply pump, and a drain valve are further provided.

[0011] Further, a temperature sensor and a pressure sensor are further provided.

[0012] The second technical solution is as follows: A fuel cell test bench wide-range humidification system control method comprises the following steps: dry gas required for the fuel cell reaction is introduced into the bottom of a humidifier, under the action of a gas distributor in the humidifier, the gas is dispersed into uniform small bubbles, a heater heats the water in the tank, the gas is uniformly humidified in the bubbling process and obtains saturated humidity, i.e. 100% RH water vapor when leaving the liquid surface, a spray device at the top of the humidifier uniformly sprays downward on the humidified gas, so that the humidified gas will not condense to produce liquid water before entering the electric pile, and when the electric pile requires different gas flow, the electric pile humidification in a wide power range is realized through the liquid level and gas volume joint control by using the structural characteristics of the developed humidification system.

[0013] Compared with the prior art, the application has the following beneficial effects: Through the design of wide-range humidification system, a single test bench can stably cover the test requirements of a 20-fold power range from 0.5kW to 10kW, without the need to purchase multiple sets of special test equipment for fuel cell stacks of different power levels, thereby greatly saving equipment procurement costs, reducing laboratory floor area, and simplifying equipment maintenance and management processes, and providing a high-performance-price-ratio solution of "one machine for multiple uses"; Through the structural optimization and control strategy innovation of the humidification system of the stack test bench, the performance degradation of the prior art under non-design conditions is fundamentally overcome; whether at an extremely low flow rate of 0.5kW or at a rated high flow rate of 10kW, the system can achieve rapid, accurate and stable control of the target dew point, effectively avoiding the dew point fluctuation, response delay under low load and insufficient humidification capacity under high load of the traditional system, thereby ensuring the consistency and reliability of the test data from low to high power range; The dynamic process is specially optimized, and the thermal inertia and flow field characteristics are improved, so that the system can quickly respond to the drastic changes of the fuel cell stack load, such as from idle to peak power; the test bench can accurately reproduce real application scenarios such as vehicle acceleration and power sudden change, effectively evaluate the performance degradation, water and heat management capability and durability of the stack under dynamic conditions, and provide key data support for the optimization and upgrading of fuel cell technology, which cannot be provided by traditional narrow-range test benches. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a structural schematic diagram of the present application. DETAILED DESCRIPTION Embodiment:

[0015] Please refer to Figure 1 , the embodiment shows a fuel cell test bench wide-range humidification system structure, comprising: Gas supply device ①: providing dry gas with stable pressure; Gas mass flow controller ②: controlling the flow rate into the humidification system to be a stable value; And also provided with humidification system tank ⑤, heater ⑥, gas distributor ⑦, cooling heat exchanger ⑨, demister ⑩; Humidifying the fuel cell stack in the wide range of 0.5~10kW: The gas distributor ⑦ disperses the dry gas required for the fuel cell reaction into uniform small bubbles; The heater ⑥ heats the water in the humidification system tank ⑤; The gas is uniformly humidified in the process of bubbling, and gets saturated humidity, i.e. 100%RH water vapor, when it leaves the liquid surface; When the electric pile needs different gas flow, the electric pile humidification in wide power range is realized by the liquid level and gas volume joint control.

[0016] The switch valve 3, the check valve 4 are further arranged.

[0017] The pneumatic diaphragm pressure regulating valve 13 is further arranged.

[0018] The spray circulating pump 7, the system water supply pump 14, the drain valve 15 are further arranged.

[0019] The temperature sensor 11, the pressure sensor 12 are further arranged.

[0020] The control method of the embodiment is as follows: The dry gas required for fuel cell reaction is introduced into the bottom of the humidifier, under the action of the gas distributor in the humidifier, the gas is dispersed into uniform small bubbles, and the heater heats the water in the tank, the gas is uniformly humidified in the process of bubbling, and the saturated humidity, i.e. 100% RH water vapor, is obtained when it leaves the liquid surface, the humidified gas is uniformly sprayed downward by the spray device at the top of the humidifier, so that the humidified gas will not condense to produce liquid water before entering the electric pile, and when the electric pile needs different gas flow, the structure characteristics of the developed humidification system are utilized, and the electric pile humidification in wide power range is realized by the liquid level and gas volume joint control.

[0021] Compared with the prior art, the beneficial effects of the present application are: Through the wide-range humidification system design, a single test bench can stably cover the test requirements of a 20-fold power range from 0.5kW to 10kW; there is no need to purchase multiple sets of special test equipment for fuel cell stacks of different power levels; the equipment procurement cost is greatly saved, the laboratory floor area is reduced, and the equipment maintenance and management process is simplified, providing a high-performance-price-ratio solution of ''one machine with multiple uses''; Through the structure optimization and control strategy innovation of the electric pile test bench humidification system, the performance degradation defect of the prior art under non-design conditions is fundamentally overcome; whether at the extremely low flow of 0.5kW or at the rated high flow of 10kW, the system can realize rapid, accurate and stable control of the target dew point, effectively avoiding the dew point fluctuation, response lag under low load and insufficient humidification capacity under high load of the traditional system, thereby ensuring the consistency and reliability of the test data from low to high power segment; The dynamic process is specially optimized, the thermal inertia and flow field characteristics are improved, the system can quickly respond to the sudden change of fuel cell stack load, such as from idle to peak power; the test bench can accurately reproduce the real application scenarios such as vehicle acceleration and power sudden change, effectively evaluate the performance attenuation, water and heat management ability and durability of the stack under dynamic working conditions, and provide key data support for the optimization and upgrading of fuel cell technology which cannot be provided by traditional narrow-range test benches.

[0022] For those skilled in the art, without departing from the inventive concept, several modifications and improvements can be made, which are within the scope of the present application.

Claims

1. A wide-area humidification system structure for a fuel cell test bench, characterized in that: include: Gas supply device: Provides dry gas at a stable pressure; Gas mass flow controller: controls the flow rate entering the humidification system to a stable value; It is also equipped with a humidification system tank, heater, gas distributor, cooling heat exchanger, and demister; Humidification of fuel cell stacks in a wide power range of 0.5~10kW: The gas distributor disperses the dry gas required for the fuel cell reaction into uniform small bubbles; The heater heats the water inside the humidification system tank; The gas is uniformly humidified during the bubbling process, and becomes saturated water vapor with 100% RH when it leaves the liquid surface. When the fuel cell stack requires different gas flow rates, fuel cell stack humidification can be achieved over a wide power range by controlling the liquid level and gas flow rate together.

2. The structure of a wide-area humidification system for a fuel cell test bench according to claim 1, characterized in that: It is also equipped with a switch valve.

3. The structure of a wide-area humidification system for a fuel cell test bench according to claim 2, characterized in that: It is also equipped with a one-way valve.

4. The structure of a wide-area humidification system for a fuel cell test bench according to claim 3, characterized in that: It is also equipped with a pneumatic diaphragm pressure regulating valve.

5. The structure of a wide-area humidification system for a fuel cell test bench according to claim 4, characterized in that: It is also equipped with a spray circulation pump.

6. The structure of a wide-area humidification system for a fuel cell test bench according to claim 5, characterized in that: It is also equipped with a system water supply pump.

7. The structure of a wide-area humidification system for a fuel cell test bench according to claim 6, characterized in that: It is also equipped with a drain valve.

8. The structure of a wide-area humidification system for a fuel cell test bench according to claim 7, characterized in that: It is also equipped with a temperature sensor.

9. The structure of a wide-area humidification system for a fuel cell test bench according to claim 8, characterized in that: It is also equipped with a pressure sensor.

10. A control method for a wide-range humidification system on a fuel cell test bench, characterized in that: Using the wide-area humidification system structure of any one of claims 1-9 to perform wide-area humidification of the fuel cell test bench, the steps are as follows: The dry gas required for the fuel cell reaction is introduced into the bottom of the humidifier. Under the action of the gas distributor inside the humidifier, the gas is dispersed into uniform small bubbles. At the same time, the heater heats the water in the tank. The gas is uniformly humidified during the bubbling process. When it leaves the liquid surface, it becomes water vapor with saturated humidity of 100% RH. The spray device at the top of the humidifier sprays the humidified gas evenly downwards, so that the humidified gas will not condense into liquid water before entering the fuel cell stack. When the fuel cell stack requires different gas flow rates, the structural characteristics of the developed humidification system are used to achieve fuel cell stack humidification over a wide power range by controlling the liquid level and gas flow.

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