Improved low-temperature purging device for fuel cell
By optimizing the pipeline connection and purge strategy of the fuel cell low-temperature purge device, the problem of ice debris accumulation in the pipeline during low-temperature shutdown was solved, and the system's normal low-temperature operation and expander protection were achieved.
Patent Information
- Application Number
- CN202422638619.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-31
- Publication Date
- 2025-09-26
- Estimated Expiration
- 2034-10-31
AI Technical Summary
During the low-temperature shutdown process of the fuel cell, the purge time is difficult to accurately control, resulting in the accumulation of ice debris in the system pipelines, affecting the normal use of the expander turbine, and thus affecting the system performance and reliability.
A fuel cell low-temperature purge improvement device was designed, including an air compressor, intercooler, humidifier, bypass valve, motor, and expander. By optimizing the pipeline connections and purge strategy, the device ensures that water in the fuel cell stack module and pipelines is blown out during low-temperature shutdown, and melts potential ice debris during low-temperature startup to prevent pipeline freezing.
It effectively prevents pipe freezing, eliminates damage to the expander turbine caused by ice debris, and ensures normal operation of the system at low temperatures.
Smart Images
Figure CN223390569U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of fuel cells, in particular to a low-temperature purge improvement device for fuel cells. Background Art
[0002] Fuel cells are a new type of energy conversion device. In low-temperature environments, they face unique problems and challenges. In the high-power range, for systems greater than 200kW, an expander (VNT) is typically used to recover some of the air compressor's energy. The high-temperature, high-pressure gas discharged from the fuel cell stack is passed through the VNT. Because the compression end of the air compressor and the turbine end of the VNT are coaxial, passing the high-temperature, high-pressure gas through the VNT can effectively reduce the power consumption of the air compressor itself. During the low-temperature shutdown process of the fuel cell, the system needs to be purged. If the purge time is insufficient, ice debris will easily form in the system's pipelines entering the VNT. This ice debris can have a serious impact on the normal operation of the VNT, such as causing pipeline blockage and damage to the turbine, thereby affecting the performance and reliability of the entire fuel cell system.
[0003] At present, the shutdown purge method commonly used in fuel cell systems is to purge for a certain period of time when shutting down. However, due to the influence of various factors, such as ambient temperature, system complexity, and the actual state of the fuel cell stack, the purge time is difficult to accurately control, which will cause ice debris to appear in the pipeline entering the expander in the system, affecting the next low-temperature cold start. Utility Model Content
[0004] The purpose of this utility model is to address the problems existing in the background technology and propose a low-temperature purge improvement device for fuel cells, which can prevent pipeline icing to the greatest extent, eliminate damage to the expander turbine caused by ice debris, and ensure normal operation of the system at low temperatures.
[0005] The technical solution of the present utility model is a low-temperature purge improvement device for a fuel cell, comprising an air compressor, an intercooler, a humidifier, a bypass valve, a motor and an expander; the input end of the intercooler is connected to the output end of the air compressor; the humidifier has a dry gas inlet, a dry gas outlet, a wet gas inlet and a wet gas outlet, the dry gas inlet of the humidifier is connected to the output end of the intercooler, the dry gas outlet is connected to the input end of the fuel cell module, and the output end of the fuel cell module is connected to the wet gas inlet of the humidifier; the bypass valve is connected to a branch pipe of a pipeline bypass between the air compressor and the input end of the fuel cell module; the input end of the expander is connected to a pipeline where the wet gas outlet circuit of the humidifier and the bypass valve circuit merge; the motor is connected to the air compressor and the expander; and the tail exhaust is connected to the output end of the expander.
[0006] Preferably, the air compressor, motor and expander are integrated into one.
[0007] Preferably, the bypass valve is connected to a branch pipe of the pipeline bypass between the air compressor and the intercooler.
[0008] Preferably, the bypass valve is connected to a branch pipe of a pipeline bypassing the intercooler and the humidifier.
[0009] Preferably, the bypass valve is connected to a branch pipe of the pipeline bypass between the dry gas outlet of the humidifier and the input end of the stack module.
[0010] Preferably, a stop valve is provided between the dry gas outlet of the humidifier and the input end of the stack module.
[0011] Preferably, a back pressure valve is provided between the output end of the stack module and the wet gas inlet of the humidifier.
[0012] Compared with the prior art, the present invention has the following beneficial technical effects:
[0013] The utility model can blow out the water in the stack module and the pipeline during low-temperature shutdown and purge, reducing the risk of pipeline freezing. It can also melt the ice residue that may exist in the system pipeline through the bypass branch during low-temperature startup and purge, thereby preventing the pipeline from freezing to the greatest extent, eliminating the damage of the expander turbine caused by ice residue, and ensuring the normal operation of the system at low temperature. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 It is a structural diagram of the utility model;
[0015] Figure 2 for Figure 1 Flow chart of low temperature shutdown purge strategy;
[0016] Figure 3 for Figure 1 Flowchart of low-temperature startup purge strategy.
[0017] Figure numerals: 1. air compressor; 2. intercooler; 3. humidifier; 4. stop valve; 5. back pressure valve; 6. bypass valve; 7. motor; 8. expander. DETAILED DESCRIPTION
[0018] like Figure 1 As shown, the present embodiment proposes an improved low-temperature purge device for a fuel cell, comprising an air compressor 1 , an intercooler 2 , a humidifier 3 , a bypass valve 6 , a motor 7 and an expander 8 .
[0019] Air compressor 1 compresses air into high-temperature, high-pressure gas. The input of intercooler 2 is connected to the output of air compressor 1, cooling the gas output from air compressor 1 to the temperature required by the fuel cell module.
[0020] Humidifier 3 has a dry gas inlet, a dry gas outlet, a wet gas inlet, and a wet gas outlet. The dry gas inlet of humidifier 3 is connected to the output of intercooler 2, humidifying the gas output from intercooler 2 to the humidity required by the stack module. The dry gas outlet of humidifier 3 is connected to the input of the stack module. A shut-off valve 4 is provided between the dry gas outlet and the stack module input. Shut-off valve 4 passes the air humidified by humidifier 3 into the stack module. The stack module output is connected to the wet gas inlet of humidifier 3. A backpressure valve 5 is provided between the stack module output and the wet gas inlet of humidifier 3 to regulate the air intake pressure at the stack module input.
[0021] The bypass valve 6 is connected to the branch pipe of the bypass between the air compressor 1 and the input end of the stack module. Figure 1 As shown in , the bypass valve 6 is connected to the branch pipe of the pipeline bypass between the intercooler 2 and the humidifier 3. At this time, for the gas output from the intercooler 2, part of the gas passes through the humidifier 3 and enters the fuel cell module, and part of the gas passes through the bypass valve 6 directly to the expander 8. In addition, there are the following two situations: 1. The bypass valve 6 is connected to the branch pipe of the pipeline bypass between the air compressor 1 and the intercooler 2. 2. The bypass valve 6 is connected to the branch pipe of the pipeline bypass between the dry gas outlet of the humidifier 3 and the input end of the fuel cell module. For the above three setting positions of the bypass valve 6, the effect achieved is the same, which can effectively purge the water in the fuel cell module and the pipeline.
[0022] The input end of the expander 8 is connected to the pipeline where the wet gas outlet circuit of the humidifier 3 and the circuit of the bypass valve 6 merge, and the output end of the expander 8 is connected to the tail exhaust. The expander 8 discharges the recovered gas through the tail exhaust.
[0023] The air compressor 1 and the expander 8 are connected via the motor 7 , so that the air compressor 1 , the motor 7 and the expander 8 are integrated into one.
[0024] like Figure 2 As shown, the low-temperature shutdown purge strategy is divided into the following two steps:
[0025] Step 1: When shutting down, keep the air compressor running to purge the water in the stack module with a large amount of gas. The purge time is based on reaching the target impedance value M0 of the stack module. After reaching the target impedance value, close the back pressure valve 5 and the stop valve 4 to complete the shutdown process.
[0026] Step 2: After closing the system's shut-off valve 4 and back-pressure valve 5, the stack module is disconnected from components such as the air compressor 1, intercooler 2, and humidifier 3. At this time, open the system's bypass valve 6 to allow the air compressor 1 to continue running. The gas output by the air compressor 1 passes through the intercooler 2 to the input end of the expander 8. After the gas output by the air compressor 1 completely dries up the gas in this pipeline, turn off the air compressor 1 to complete the shutdown process. The purge time is T0, and the T0 value is measured based on the test.
[0027] like Figure 3 As shown, the low-temperature startup purge strategy is as follows:
[0028] Before the system enters normal startup and purge, the system opens bypass valve 6 and air compressor 1. When the temperature at the outlet of air compressor 1 reaches a certain value T, the system continues to purge for a period of time t. t can be measured through testing. That is, the ice residue in the pipeline can be completely melted after being purged with gas at temperature T for t time. After the ice residue is completely melted, the system performs normal purge and startup.
[0029] This embodiment can blow out the water inside the stack module during low-temperature shutdown purging, and can also purge the water entering the pipeline, reducing the risk of pipeline freezing. It can also melt the ice residue that may exist in the system pipeline through the bypass branch during low-temperature startup purging, thereby preventing pipeline freezing to the greatest extent, eliminating damage to the expander turbine caused by ice residue, and ensuring normal operation of the system at low temperature.
[0030] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto. Various changes can be made within the knowledge scope of those skilled in the art without departing from the purpose of the present invention.
Claims
1. A fuel cell low-temperature purge improvement device, characterized in that: include: Air compressor (1); An intercooler (2), the input end of which is connected to the output end of the air compressor (1); A humidifier (3) having a dry gas inlet, a dry gas outlet, a wet gas inlet, and a wet gas outlet, wherein the dry gas inlet of the humidifier (3) is connected to the output end of the intercooler (2), the dry gas outlet is connected to the input end of the stack module, and the output end of the stack module is connected to the wet gas inlet of the humidifier (3); A bypass valve (6) is connected to a branch pipe of a bypass line between the air compressor (1) and the input end of the stack module; an expander (8), the input end of which is in communication with a pipeline where a wet gas outlet circuit of a humidifier (3) and a circuit of a bypass valve (6) merge; a motor (7) connected to the air compressor (1) and the expander (8); The tail row is connected to the output end of the expander (8).
2. A fuel cell low-temperature purge improvement device according to claim 1, characterized in that: The air compressor (1), the motor (7) and the expander (8) are integrated into one body.
3. A fuel cell low-temperature purge improvement device according to claim 1, characterized in that: The bypass valve (6) is connected to a branch pipe of the pipeline bypass between the air compressor (1) and the intercooler (2).
4. A fuel cell low-temperature purge improvement device according to claim 1, characterized in that: The bypass valve (6) is connected to a branch pipe of the pipeline bypass between the intercooler (2) and the humidifier (3).
5. A fuel cell low-temperature purge improvement device according to claim 1, characterized in that: The bypass valve (6) is connected to a branch pipe of the pipeline bypass between the dry gas outlet of the humidifier (3) and the input end of the stack module.
6. A fuel cell low-temperature purge improvement device according to claim 1, characterized in that: A stop valve (4) is provided between the dry gas outlet of the humidifier (3) and the input end of the stack module.
7. A fuel cell low-temperature purge improvement device according to claim 6, characterized in that: A back pressure valve (5) is provided between the output end of the stack module and the wet gas inlet of the humidifier (3).