CN114914475A - Electric pile heat management method of proton membrane fuel cell - Google Patents

Abstract

A pile heat management method of proton membrane fuel cell, including filling liquid-gas phase change working medium in pile heat management system and making the filling amount reach the best filling amount; when the galvanic pile thermal management system works, the heater is controlled, the pressure of a liquid-gas phase change working medium in the galvanic pile thermal management system reaches 0.4-0.405 MPa, the temperature values of the first temperature-pressure sensor and the second temperature-pressure sensor are kept at 70-71 ℃ through the heater, the mechanical pump and the electromagnetic flow valve, and the flow value of the flowmeter is kept at 20-30% of the output flow value of the mechanical pump. The temperature of liquid-gas phase change working media in the phase change cold plates of the electric pile is the same, the surface temperature of all the cold plates is consistent and high, and the working temperature of an exchange membrane in the proton exchange membrane fuel cell is kept at 70-90 ℃.

Description

A stack thermal management method for a proton membrane fuel cell

technical field

The invention relates to a proton membrane fuel cell, in particular to a stack thermal management method for the proton membrane fuel cell.

Background technique

Proton exchange membrane fuel cell is a fuel cell stack, as a real green energy, its extremely high theoretical specific energy (for the hydrogen-air system, its theoretical specific energy is as high as 32940WhP kg, which is much larger than Existing any other chemical power source) is considered to be one of the most important energy sources for future vehicles, distributed power stations and various electronic products. The stack of the proton exchange membrane fuel cell has high requirements on temperature and water content. The working temperature of the exchange membrane is 70 to 90 ° C. If the temperature exceeds this temperature, the water content will drop sharply, and the electrical conductivity will drop rapidly.

SUMMARY OF THE INVENTION

In view of the problems in the prior art, the present invention provides a stack thermal management method for a proton membrane fuel cell, which aims to keep the working temperature of the exchange membrane in the proton exchange membrane fuel cell at 70-90°C.

A stack thermal management method for a proton membrane fuel cell, comprising a stack thermal management system, the stack thermal management system comprising a stack phase change cold plate arranged in the stack, and the stack phase change cold plate is There are several independent flow channels, an electromagnetic flow valve is arranged on the liquid inlet of each of the flow channels, and a first temperature and pressure sensor is arranged on the liquid outlet of each of the flow channels. The liquid outlets of the channel are all connected with the gas-liquid separator, and the liquid outlet at the lower part of the gas-liquid separator is connected to each of the electromagnetic flow valves through a flow meter, a filter, a mechanical pump, and a second temperature and pressure sensor in turn. are connected, an expansion tank is arranged on the pipeline between the mechanical pump and the filter, a heater is arranged on the pipeline and the expansion tank, and the air outlet of the gas-liquid separator is connected to the The liquid inlet of the filter is communicated;

The stack thermal management method includes charging liquid-phase change working medium in the stack thermal management system and making the charging amount reach an optimum charging amount; when the stack thermal management system is working, controlling the heater and After the pressure of the liquid-phase changeable working medium in the stack thermal management system reaches 0.4 MPa ~ 0.405 MPa, the temperature values of the first temperature and pressure sensor and the second temperature and pressure sensor are maintained through the heater, mechanical pump and electromagnetic flow valve. At 70℃~71℃, keep the flow value of the flowmeter at 20%~30% of the output flow value of the mechanical pump.

Further: the optimal charging amount is to make the stack phase change cold plate in the working condition environment of 55 ℃, fill the liquid-phase change working medium in the stack thermal management system, and make the initial amount of liquid-phase change The working medium circulates in the stack thermal management system, and after the temperature difference between the first temperature and pressure sensors is stable, the liquid-gas phase change working medium is injected into the stack thermal management system until the first temperature and pressure sensor When the temperature difference between them is less than A, stop filling the liquid-phase change working medium into the stack thermal management system, and the value of A is between 0.1°C and 1°C.

In order to avoid the short circuit of the proton membrane fuel cell caused by the leakage of the liquid-gas phase change working medium, further: the liquid-phase change working medium is an insulating material.

Further: the liquid-gas phase change working substance is R134a, or R113, or R11, or R407c, or R410A.

Since the liquid working medium will contain metal impurities after circulation, in order to avoid these impurities affecting the life of the mechanical pump, further: the filtration accuracy of the filter is less than 60um.

In order to avoid damage to the mechanical pump due to the high hydraulic pressure at the liquid inlet of the mechanical pump, further: a safety valve is installed between the liquid inlet and the liquid outlet of the mechanical pump.

In order to improve the heat exchange efficiency of the condenser, further: a capillary structure is arranged in the heat exchange flat tube of the condenser. In actual work, the liquid working medium flows in the capillary structure, and the gas working medium is large in the heat exchange flat tube. Space flow, two-phase flow liquid realizes gas-liquid separation in working state, avoids mutual interference between gas and liquid when exchanging heat with the outside world, and significantly improves heat exchange efficiency.

In order to improve the heat exchange efficiency of the stack phase change cold plate, further: the inside of the flow channel is a capillary structure.

Further: the capillary structure is formed by microchannels or sintered wire mesh or sintered core.

The beneficial effects of the present invention: the temperature of the liquid and gas phase change working medium inside the stack phase change cold plate is the same, and the surface temperature of all the cold plates is uniformly high, so that the working temperature of the exchange membrane in the proton exchange membrane fuel cell is maintained at 70-90°C, so that the The battery is kept working under ideal temperature conditions; the liquid-phase change working medium is combined with the stack phase change cold plate with capillary structure to ensure the temperature uniformity of the stack during operation and improve the stack of the proton exchange membrane fuel cell. The cooling effect is improved, and the stack heat capacity and service life of the proton exchange membrane fuel cell are improved.

Description of drawings

FIG. 1 is a system structure diagram of the present invention.

In the figure, 1, mechanical pump; 2, safety valve; 3, second temperature and pressure sensor; 4, electromagnetic flow valve; 5, stack phase change cold plate; 6, first temperature and pressure sensor; 7, controller; 8 , gas-liquid separator; 10, condenser; 11, filter; 12, liquid injection valve; 13, expansion tank; 14, heater; 15, flow meter.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings. The following describes in detail the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, but not to be construed as a limitation of the present invention. Orientation terms such as left, middle, right, upper and lower in the examples of the present invention are only relative concepts to each other or refer to the normal use state of the product, and should not be regarded as limiting.

A stack thermal management method for a proton membrane fuel cell, comprising a stack thermal management system, the stack thermal management system comprising a stack phase change cold plate 5 arranged in the stack, the stack phase change cold plate 5 is provided with several independent flow channels, the inside of the flow channel is a capillary structure, an electromagnetic flow valve 4 is arranged on the liquid inlet of each of the flow channels, and an electromagnetic flow valve 4 is arranged on the liquid outlet of each of the flow channels. A first temperature and pressure sensor 6 is provided, and the liquid outlet of the flow channel is connected with the gas-liquid separator 8. The liquid outlet of the lower part of the gas-liquid separator 8 passes through the flow meter 15, the filter 11, the mechanical The pump 1 and the second temperature and pressure sensor 3 are connected to each of the electromagnetic flow valves 4, and an expansion tank 13 is arranged on the pipeline between the mechanical pump 1 and the filter 11. Filled with a saturated liquid-phase changeable working medium, a heater 14 is arranged on the pipeline and on the expansion tank 13, and the gas outlet of the gas-liquid separator 8 passes through the condenser 10 and communicates with the filter 11. The liquid inlet is connected. Expansion tank 13 contains gaseous and liquid working fluids in a saturated state. Expansion tank 13 is used to control and adjust the working temperature and pressure of the liquid-to-gas phase change working fluid in the thermal management system of the stack, and to heat the gaseous and liquid working fluids in expansion tank 13. , After the liquid-phase working medium is heated, the saturation temperature and pressure of the liquid-gas transforming working medium in the thermal management system of the stack will increase, that is, the liquid working medium will change into a gaseous state, the gaseous working medium pressure will increase, and the liquid working medium pressure will also increase. High; wherein, the filtering precision of the filter 11 is less than 60um. A safety valve 2 is installed between the liquid inlet and the liquid outlet of the mechanical pump 1 . A capillary structure is arranged in the heat exchange flat tube of the condenser 10, and the capillary structure is formed by micro-channels or sintered wire mesh or sintered core;

The stack thermal management method includes filling the liquid-gas phase change working medium in the stack thermal management system and making the charging amount reach the optimum charging amount, and injecting the liquid into the stack thermal management system through the liquid injection valve 12 of the expansion tank 13 Fill the liquid-phase change working medium; when the stack thermal management system is working, control the heater and make the pressure of the liquid-gas change working medium in the stack heat management system reach 0.4MPa ~ 0.405MPa, then pass the heater 14, mechanical The pump 1 and the electromagnetic flow valve 4 keep the temperature values of the first temperature and pressure sensor 6 and the second temperature and pressure sensor 3 at 70°C to 71°C, and keep the flow rate value of the flow meter 15 at the output flow rate value of the mechanical pump 1 . If the flow rate is too large, it means that the system margin is too large, which is uneconomical; if the flow rate is too small, it will bring a certain risk of heat dissipation. In extreme cases, the temperature of the stack may be too high; The stack phase change cold plate 5 absorbs the heat generated during the operation of the stack, and about 70-80% of the liquid-phase change working medium absorbs heat and changes into a gas-liquid mixture, thereby ensuring that the stack of the proton membrane fuel cell is in operation. The working temperature is 70-90°C, which ensures the temperature uniformity of the stack of the proton membrane fuel cell during operation, improves the cooling effect of the stack of the proton membrane fuel cell, and improves the heat capacity and service life of the stack of the proton membrane fuel cell. . The condenser and heater are used to ensure the stability of the working temperature and pressure of the stack thermal management system.

Summary: When the phase transition pressure changes synchronously with the accompanying temperature, when the phase transition pressure exceeds a certain range and the pressure is high, the working temperature of the stack is high and the stability is poor. When the pressure is low, the working temperature of the stack is good, but the cost is high and the implementability is poor.

The optimal charging amount is to make the stack phase change cold plate in the working condition environment of 55 ° C, to charge the liquid-phase change working medium in the stack thermal management system, and to make the initial amount of the liquid-phase change working medium. The stack thermal management system is circulated, and after the temperature difference between the first temperature and pressure sensors 6 is stable, the liquid-phase change working medium is injected into the stack thermal management system until the first temperature and pressure sensor 6 When the temperature difference between them is less than A, stop filling the liquid-phase change working medium into the stack thermal management system, and the value of A is between 0.1°C and 1°C. The temperature of the working medium inside the stack phase change cold plate 5 is the same, and the surface temperature of the stack phase change cold plate 5 is almost the same, which ensures that the battery works under ideal temperature conditions. The charging amount at this time is the optimal charging amount. When working at 55°C, the temperature difference of the working fluid can be kept within a very small range, so that there will be no waste caused by too much charging, and there will be no high working temperature of the stack caused by too little charging. Ensure the safe and stable operation of the system. The liquid-phase change working medium is an insulating material, and the liquid-phase changing working medium is R134a, or R113, or R11, or R407c, or R410A, and the mechanical pump 1 provides the driving force for the liquid-phase changing working medium, The liquid-phase change working medium flows in other components in the thermal management system of the stack, and the liquid-phase working medium absorbs heat through the stack phase change cold plate 5 and then changes into a two-phase gas-liquid mixed working medium, and the two-phase gas-liquid The mixed working medium enters the gas-liquid separator 8, the liquid working medium is separated and enters the filter 11, the gaseous working medium enters the condenser 10 and is cooled by the ambient atmosphere into a liquid working medium, and then enters the filter 11, and the liquid produced after passing through the condenser 10. The working fluid and the liquid working fluid separated by the gas-liquid separator 8 are combined into the filter 11 for filtration, so that the cleanliness of the fluid is higher than 60 μm, and then returned to the mechanical pump 1 to complete a cycle.

The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above-mentioned embodiments, and the descriptions in the above-mentioned embodiments and the description are only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have Various changes and modifications fall within the scope of the claimed invention. The claimed scope of the present invention is defined by the appended claims and their equivalents.

Claims (9)

1. A stack thermal management method for a proton membrane fuel cell, characterized in that: comprising a stack thermal management system, the stack thermal management system comprising a stack phase change cold plate arranged in the stack, the electricity The stack phase change cold plate is provided with several independent flow channels, an electromagnetic flow valve is arranged on the liquid inlet of each of the flow channels, and a first temperature temperature is arranged on the liquid outlet of each of the flow channels. Pressure sensor, the liquid outlet of the flow channel is connected with the gas-liquid separator, and the liquid outlet at the lower part of the gas-liquid separator is connected with each gas-liquid separator through the flow meter, filter, mechanical pump, and second temperature and pressure sensor in sequence. All the electromagnetic flow valves are connected, an expansion tank is arranged on the pipeline between the mechanical pump and the filter, a heater is arranged on the pipeline and the expansion tank, and the air outlet of the gas-liquid separator After passing through the condenser, it is communicated with the liquid inlet of the filter; the thermal management method of the stack includes filling the liquid-gas phase change working medium in the thermal management system of the stack and making the charging amount reach the optimum charging amount When the stack thermal management system is working, the heater is controlled and the pressure of the liquid-gas phase change working medium in the stack thermal management system reaches 0.4MPa ~ 0.405MPa, and then the heater, mechanical pump and electromagnetic flow valve are used to make all the The temperature values of the first temperature and pressure sensor and the second temperature and pressure sensor are kept at 70°C to 71°C, and the flow rate of the flow meter is kept at 20% to 30% of the output flow value of the mechanical pump. 2 . The stack thermal management method for a proton membrane fuel cell according to claim 1 , wherein the optimal charging amount is to keep the stack phase change cold plate in a working condition environment of 55° C. 3 . , filling the stack thermal management system with the liquid-phase change working medium, and making the initial amount of the liquid-phase change working medium circulate in the stack heat management system, and after the temperature difference between the first temperature and pressure sensors is stabilized Then add the liquid-phase change working medium into the stack thermal management system, until the temperature difference between the first temperature and pressure sensors is less than A, stop filling the liquid-gas change working medium into the stack thermal management system, the A The value is between 0.1°C and 1°C. 3 . The stack thermal management method for a proton membrane fuel cell according to claim 1 , wherein the liquid-gas phase change working medium is an insulating material. 4 . 4 . The stack thermal management method for a proton membrane fuel cell according to claim 1 , wherein the liquid-gas phase change working medium is R134a, or R113, or R11, or R407c, or R410A. 5 . The stack thermal management method for a proton membrane fuel cell according to claim 1 , wherein the filtering precision of the filter is less than 60um. 6 . 6 . The stack thermal management method for a proton membrane fuel cell according to claim 1 , wherein a safety valve is installed between the liquid inlet and the liquid outlet of the mechanical pump. 7 . 7 . The stack thermal management method for a proton membrane fuel cell according to claim 1 , wherein a capillary structure is arranged in the heat exchange flat tube of the condenser. 8 . 8 . The stack thermal management method for a proton membrane fuel cell according to claim 1 , wherein the flow channel has a capillary structure. 9 . 9 . The stack thermal management method for a proton membrane fuel cell according to claim 7 or 8 , wherein the capillary structure is formed by microchannels, sintered wire mesh or sintered core. 10 .

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