A low temperature start-up system for a proton exchange membrane fuel cell
By connecting a magnetic conductor with an energized coil wound around both ends of the fuel cell and the power lithium battery, heat is generated by utilizing the hysteresis effect of the alternating magnetic field, which solves the problem of difficult start-up of fuel cells in low-temperature environments and achieves uniform heating and increased output power.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING SINOHYTEC
- Filing Date
- 2023-01-05
- Publication Date
- 2026-06-30
AI Technical Summary
In low-temperature environments, lithium batteries are prone to lithium plating, resulting in poor discharge capacity, difficulty in starting fuel cells, and uneven heating leading to limited output power.
The heating component employs a hysteresis effect. By connecting magnetic conductors with energized coils to both ends of the fuel cell and the power lithium battery, heat is generated in the metal parts using the hysteresis effect produced by the alternating magnetic field. During the heating process, the frequency of the alternating current is adjusted by a frequency converter, and uniform heating is achieved by combining temperature monitoring and solenoid valve control.
It effectively shortens the low-temperature start-up time of fuel cells, solves the problems of uneven heating and limited output power, and improves the start-up efficiency of fuel cells.
Smart Images
Figure CN116278989B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of fuel cell technology, and in particular to a low-temperature start-up system for a proton exchange membrane fuel cell. Background Technology
[0002] The power system of a fuel cell vehicle generally includes a fuel cell, a DC-DC converter, and a lithium-ion battery. The fuel cell is where the electrochemical reaction occurs; the DC-DC converter stabilizes the fuel cell's output voltage; and the lithium-ion battery improves the output power variation of the fuel cell and, during low-temperature startup, serves as a power source for the heater to heat the fuel cell.
[0003] In low-temperature environments, lithium-ion batteries are prone to lithium plating and have reduced discharge capacity, making it impossible to power the heater, especially in ultra-low temperature environments below -20°C. Water freezing can easily cause the fuel cell to stop abruptly during initial startup, limiting the engine's net output power and reducing heat generation, further complicating the low-temperature startup of the fuel cell.
[0004] Currently, there are two main methods for low-temperature start-up of fuel cells: auxiliary heating and self-starting heating. Self-starting heating controls the overpotential of the output operating point voltage to increase heat generation. However, this method places high demands on the control of the fuel cell system and the consistency of individual cells. If the stack consistency is poor, uneven heat generation will occur, and reverse polarity or even stack burn-out can easily occur. Auxiliary start-up methods involve using external heaters to heat the coolant, gas, or stack components. Heating the coolant has a slow heating rate. Heating the gas is extremely inefficient, as gas is a poor conductor of heat. Heating stack components requires built-in resistance wires, which places high demands on the fabrication of stack components and results in uneven heating. Summary of the Invention
[0005] Based on the above analysis, the present invention aims to provide a low-temperature start-up system for proton exchange membrane fuel cells to solve the problems of excessively long heating time, uneven heating, and limited output power of fuel cells during low-temperature start-up in the prior art.
[0006] On one hand, embodiments of the present invention provide a cryogenic start-up system for a proton exchange membrane fuel cell, including a hysteresis heating assembly, a power lithium battery, a fuel cell, a DC-DC converter, a DC-AC converter, a frequency converter, and a first solenoid valve; wherein,
[0007] The hysteresis heating assembly includes a magnetic conductor and an energized coil wound around the magnetic conductor; the magnetic conductor has a first magnetic conductor opening for inserting a power lithium battery and a second magnetic conductor opening for inserting a fuel cell;
[0008] The first solenoid valve, the energized coil, and the frequency converter are connected in sequence to form a hysteresis effect generating circuit for generating an alternating magnetic field; the power output terminal of the fuel cell is connected to the electrical signal input terminal of the hysteresis effect generating circuit after passing through a DC-DC converter and a DC-AC converter in sequence.
[0009] The beneficial effects of the above technical solution are as follows: Based on the principle of hysteresis heating, the fuel cell and the power lithium battery are connected at both ends to the ends of a magnetic conductor wound with an energized coil. The fuel cell outputs alternating current through a DC-DC converter and a DC-AC converter. When the alternating current passes through the energized coil, it generates a magnetic field of the same frequency. An alternating magnetic field is constructed at both ends of the fuel cell and the power lithium battery through the magnetic conductor. In the alternating magnetic field, the magnetic conductor (before the magnetic decay temperature) will generate heat due to the hysteresis effect. The metal components in the fuel cell (including bipolar plate stacks with stainless steel and other metal materials) and the power lithium battery are spontaneously magnetized in the magnetic field to form many magnetic domain structures. The magnetic pole direction of the magnetic domains in the alternating magnetic field will also change with the direction of the magnetic field. When the magnetic pole direction of the magnetic domains changes, they will rub against the surrounding magnetic domains and generate heat. The higher the frequency of the alternating current, the more intense the friction between the magnetic domains, and the more heat is generated. The frequency of the alternating current is increased by a frequency converter to solve the problems of long heating time, uneven heating, and limited output power during low-temperature start-up of proton exchange membrane stacks (which can be used for coil heat generation).
[0010] Based on further improvements to the above system, the magnetic conductor is an H-type magnetic conductor; wherein...
[0011] A power lithium battery is placed in the middle of the opening on one side of the H-shaped magnetic conductor, and a fuel cell is placed in the middle of the opening on the other side. An energized coil is wound on the magnetic conductor beam in the middle.
[0012] Furthermore, the magnetic conductor includes a first magnetic conductor ring and a second magnetic conductor ring; wherein,
[0013] Both the first magnetic conductor ring and the second magnetic conductor ring adopt a circular or polygonal ring structure with one end open, and each ring structure has an independently set energized coil with a different number of turns wound on one side surface.
[0014] The opening of the annular structure of the first magnetic conductor ring is connected to the surface of the power lithium battery casing, and the opening of the annular structure of the second magnetic conductor ring is connected to the stack end plate of the fuel cell.
[0015] Furthermore, the cryogenic start-up system also includes a second solenoid valve; wherein,
[0016] One end of the second solenoid valve is connected to the output of the DC-DC converter, and the other end is connected to the charging terminal of the power lithium battery.
[0017] Furthermore, the cryogenic start-up system also includes a third solenoid valve; wherein,
[0018] One end of the third solenoid valve is connected to the output terminal of the DC-DC converter, and the other end is connected to the power supply input terminal of the energized coil on the first magnetic conductor ring.
[0019] One end of the first solenoid valve is connected to the output terminal of the DC-DC converter, and the other end is connected to the power supply input terminal of the energized coil on the second magnetic conductor ring.
[0020] Furthermore, the cryogenic start-up system also includes:
[0021] The first temperature monitoring device is located in the external circulation loop of the fuel cell's coolant and is used to monitor the real-time temperature of the fuel cell.
[0022] The second temperature monitoring device is installed on the surface of the power lithium battery casing to monitor the real-time temperature of the power lithium battery.
[0023] Furthermore, the cryogenic start-up system also includes:
[0024] The controller is used to control the start-up of the fuel cell, and simultaneously close the first solenoid valve and open the second solenoid valve; and, during the start-up process of the fuel cell, when the real-time data of the first temperature monitoring device is detected to be greater than the first set temperature, the first solenoid valve is opened, and the second solenoid valve is closed when the real-time data of the second temperature monitoring device is greater than the second set temperature.
[0025] The controller's input terminals are connected to the output terminals of the first temperature monitoring device and the second temperature monitoring device, respectively, and its output terminals are connected to the control terminals of the fuel cell, the first solenoid valve, and the second solenoid valve, respectively.
[0026] Furthermore, the controller executes the following program:
[0027] Upon receiving the fuel cell low-temperature start-up control command, the system controls the fuel cell to start, simultaneously closing the first solenoid valve and opening the second solenoid valve.
[0028] The system periodically monitors whether the real-time data of the first temperature monitoring device is greater than the first set temperature. If it is, the first solenoid valve is disconnected and the fuel cell is switched to the load state. Otherwise, the first solenoid valve is kept closed and the monitoring of the real-time data of the first temperature monitoring device continues in the next cycle.
[0029] The system periodically monitors whether the real-time data of the second temperature monitoring device is greater than the second set temperature. If so, the system closes the second solenoid valve and returns to the previous step of periodically monitoring whether the real-time data of the first temperature monitoring device is greater than the first set temperature. Otherwise, the system maintains the open state of the second solenoid valve and continues monitoring the real-time data of the second temperature monitoring device in the next cycle.
[0030] Furthermore, the magnetic conductor is made of one of the following materials: iron, cobalt, and nickel.
[0031] Furthermore, both the first magnetic conductor opening and the second magnetic conductor opening have two oppositely arranged, parallel end faces with equal areas.
[0032] The two end faces of the second magnetic conductor opening are parallel to the plane containing the bipolar plates and membrane electrodes in the fuel cell.
[0033] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:
[0034] 1. Two typical hysteresis effect heating component structures are provided. One involves placing a power lithium battery at each end of an H-shaped magnetic conductor, with an energized coil wound around the central magnetic conductor beam. The fuel cell powers this coil. The other involves two independent magnetic conductor rings, each with an energized coil wound around it. The opening of the first magnetic conductor ring is used to insert a power lithium battery for heating, with an alternating magnetic field generated controlled by a first solenoid valve. The opening of the second magnetic conductor ring is used to insert a fuel cell for heating, with an alternating magnetic field generated controlled by a third solenoid valve. Both schemes can effectively heat the fuel cell and the power lithium battery.
[0035] 2. A second solenoid valve and a charging branch for the power lithium battery controlled by the second solenoid valve are installed. When the fuel cell output power is high and the fuel cell temperature exceeds the first set temperature, the above-mentioned charging branch is activated to charge the power lithium battery. This increases the ways in which the fuel cell output power is consumed, so that in addition to supplying a portion of the power to the BOP, the excess power of the fuel cell can be used for heat generation through the coil and for charging the power lithium battery. Therefore, compared with the existing technology, there is no need to limit the output power of the fuel cell, effectively improving the start-up efficiency of the fuel cell.
[0036] 3. When the temperature of the power lithium battery is higher than the second set temperature, the second solenoid valve is closed to charge the power lithium battery, so as to ensure the charging and use of the power lithium battery.
[0037] The summary section is provided to present the chosen concepts in a simplified form, which will be further described in the detailed description below. The summary section is not intended to identify essential or necessary features of this disclosure, nor is it intended to limit the scope of this disclosure. Attached Figure Description
[0038] The above and other objects, features and advantages of this disclosure will become more apparent from the accompanying drawings, in which like reference numerals generally denote like parts.
[0039] Figure 1 A schematic diagram of the low-temperature start-up system of the proton exchange membrane fuel cell in Example 1 is shown;
[0040] Figure 2 A schematic diagram of the low-temperature start-up system of the proton exchange membrane fuel cell in Example 2 is shown.
[0041] Figure 3 A schematic diagram of the low-temperature start-up system of the proton exchange membrane fuel cell in Example 2 is shown.
[0042] Figure label:
[0043] 1-Hysteresis heating component; 2-Power lithium battery; 3-Fuel cell; 4-DC-DC converter; 5-DC-AC converter; 6-Inverter; 7-First solenoid valve; 8-Controller; 9-Second solenoid valve; 10-First temperature monitoring device; 11-Second temperature monitoring device; 12-Third solenoid valve. Detailed Implementation
[0044] Embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.
[0045] The term "comprising" and its variations as used herein signify open inclusion, i.e., "including but not limited to". Unless otherwise stated, the term "or" means "and / or". The term "based on" means "at least partially based on". The terms "one example embodiment" and "one embodiment" mean "at least one example embodiment". The term "another embodiment" means "at least one additional embodiment". The terms "first", "second", etc., may refer to different or the same objects. Other explicit and implicit definitions may also be included below.
[0046] Example 1
[0047] One embodiment of the present invention discloses a low-temperature start-up system for a proton exchange membrane fuel cell, such as... Figure 1 As shown, it includes a hysteresis heating component, a power lithium battery, a fuel cell, a DC-DC converter, a DC-AC converter, a frequency converter, and a first solenoid valve.
[0048] The hysteresis heating assembly includes a magnetic conductor and an energized coil wound around the magnetic conductor. The magnetic conductor has a first magnetic conductor opening for inserting a power lithium battery and a second magnetic conductor opening for inserting a fuel cell. The shape of the magnetic conductor can be limited according to actual needs, such as... Figures 1-3 As shown, but not limited to Figures 1-3 The range shown.
[0049] The first solenoid valve, the energized coil, and the frequency converter are connected in sequence to form a hysteresis effect generating circuit for generating an alternating magnetic field; the power output terminal of the fuel cell is connected to the electrical signal input terminal of the hysteresis effect generating circuit after passing through a DC-DC converter and a DC-AC converter in sequence.
[0050] A frequency converter is used to control the frequency of alternating current (AC) to a set frequency. The higher the AC frequency, the more heat is generated and the faster the heating process.
[0051] Preferably, the set frequency is 10 kHz. The optimal operating frequency for the hysteresis effect is around 10 kHz.
[0052] The first solenoid valve is used to control the current flow of the energized coil.
[0053] In implementation, the fuel cell supplies alternating current (AC) to the energized coil via a DC-DC converter and a DC-AC converter. Under the influence of the AC current, a magnetic conductor creates an alternating magnetic field across the fuel cell and the lithium-ion battery. The metal components in the fuel cell and the lithium-ion battery heat up under the influence of this alternating magnetic field (graphite plates generate heat through eddy currents, while magnetic metal plates generate heat through hysteresis and eddy currents), raising the temperature of the fuel cell and the lithium-ion battery through heat conduction. During this process, the output power of the fuel cell does not need to be limited. Besides supplying a portion of the power to the BOP (Balance of Plant), the excess power can be used to generate heat for the coil, thus heating both the fuel cell and the lithium-ion battery and solving the output power limitation problem during startup.
[0054] Compared with existing technologies, the low-temperature start-up system provided in this embodiment is based on the principle of hysteresis heating. The fuel cell and the power lithium battery are connected at both ends to a magnetic conductor wound with an energized coil. The fuel cell outputs alternating current (AC) through a DC-DC converter and a DC-AC converter. When the AC current passes through the energized coil, it generates a magnetic field of the same frequency. An alternating magnetic field is constructed at both ends of the fuel cell and the power lithium battery through the magnetic conductor. In the alternating magnetic field, the magnetic conductor (before the magnetic decay temperature) generates heat due to the hysteresis effect. The metal components in the fuel cell (including a bipolar stack with stainless steel or other metal materials) and the power lithium battery spontaneously magnetize in the magnetic field, forming many magnetic domain structures. The magnetic pole direction of the magnetic domains in the alternating magnetic field also changes with the direction of the magnetic field. When the magnetic pole direction of a domain changes, it rubs against surrounding domains, generating heat. The higher the AC frequency, the more intense the friction between the domains, and the more heat is generated. A frequency converter is used to increase the AC frequency, which solves the problems of long heating time, uneven heating, and limited output power during low-temperature start-up of proton exchange membrane fuel cells (this can be used for coil heat generation).
[0055] Example 2
[0056] An improvement was made to Example 1, in which an H-type magnetic conductor was used, such as... Figure 2 As shown, a locking mechanism for limiting the fuel cell can also be added as needed.
[0057] The H-shaped magnetic conductor has a power lithium battery 2 inserted in the middle of one side opening and a fuel cell 3 inserted in the middle of the other side opening. An energized coil is wound on the magnetic conductor beam in the middle.
[0058] Preferably, the cryogenic start-up system further includes a second solenoid valve 9.
[0059] One end of the second solenoid valve 9 is connected to the output end of the DC-DC converter 4, and the other end is connected to the charging end of the power lithium battery 2. It is used to control the fuel cell 3 to charge the power lithium battery 2 after closing.
[0060] Preferably, the low-temperature start-up system further includes a first temperature monitoring device 10 and a second temperature monitoring device 11.
[0061] The first temperature monitoring device 10 is installed in the external circulation loop of the coolant in the fuel cell 3 and is used to monitor the real-time temperature of the fuel cell 3.
[0062] The second temperature monitoring device 11 is installed on the surface of the casing of the power lithium battery 2 and is used to monitor the real-time temperature of the power lithium battery 2.
[0063] Preferably, the cryogenic start-up system further includes a controller 8.
[0064] The controller 8 is used to control the start-up of the fuel cell 3 (by supplying fuel gas and air), and simultaneously close the first solenoid valve 7 and open the second solenoid valve 9; and, when the real-time data of the first temperature monitoring device 10 is detected to be greater than the first set temperature during the start-up of the fuel cell 3, the first solenoid valve 7 is opened (the fuel cell 3 is no longer heated, and parameters can be switched for load application); and when the real-time data of the second temperature monitoring device 11 is detected to be greater than the second set temperature, the second solenoid valve 9 is closed (the fuel cell 3 charges the power lithium battery 2).
[0065] Preferably, the controller 8 executes the following program:
[0066] S1. After receiving the low-temperature start-up control command for fuel cell 3, control the fuel cell 3 to start, and at the same time close the first solenoid valve 7 and open the second solenoid valve 9.
[0067] S2. Periodically monitor whether the real-time data of the first temperature monitoring device 10 is greater than the first set temperature. If so, disconnect the first solenoid valve 7 and control the fuel cell 3 to switch to the load state. Otherwise, keep the first solenoid valve 7 closed and continue monitoring the real-time data of the first temperature monitoring device 10 in the next cycle.
[0068] S3. Periodically monitor whether the real-time data of the second temperature monitoring device 11 is greater than the second set temperature. If it is, close the second solenoid valve 9 and return to step S2 above. Otherwise, keep the second solenoid valve 9 in the open state and continue monitoring the real-time data of the second temperature monitoring device 11 in the next cycle.
[0069] The input terminals of the controller 8 are connected to the output terminals of the first temperature monitoring device 10 and the second temperature monitoring device 11, respectively, and its output terminals are connected to the control terminals of the fuel cell 3, the first solenoid valve 7, and the second solenoid valve 9, respectively.
[0070] Preferably, the controller 8 has a display module; and the display screen of the display module displays real-time data of the first temperature monitoring device 10 and the second temperature monitoring device 11 during the start-up process of the fuel cell 3.
[0071] Preferably, the magnetic conductor is made of one of the following materials: iron, cobalt, and nickel.
[0072] Preferably, both the first magnetic conductor opening and the second magnetic conductor opening have two oppositely arranged, parallel, and equal-area end faces to form a closed loop between the power lithium battery 2 / fuel cell 3 and the magnetic conductor. The resulting alternating magnetic field is confined within the area where the power lithium battery 2 / fuel cell 3 is located, reducing the risk of electromagnetic interference to other electrical components.
[0073] The two end faces of the second magnetic conductor opening are parallel to the plane containing the bipolar plate and membrane electrode in the fuel cell 3.
[0074] Preferably, the cryogenic start-up system further includes a fuel gas recirculation device.
[0075] The input end of the fuel gas circulation device is connected to the fuel gas exhaust outlet of the fuel cell 3, and the output end is connected to the fuel gas inlet of the fuel cell 3.
[0076] Graphite plates rely on eddy currents for heat generation, while magnetic metal plates rely on both magnetic hysteresis and eddy currents for heat generation.
[0077] Compared with the prior art, this embodiment has the following beneficial effects:
[0078] 1. A typical hysteresis heating component 1 structure is provided, which involves placing a power lithium battery 2 at each end of an H-shaped magnetic conductor, and winding an energized coil on the magnetic conductor beam in the middle, with the fuel cell 3 supplying power to the energized coil. This scheme can effectively heat both the fuel cell 3 and the power lithium battery 2.
[0079] 2. A second solenoid valve 9 is provided, along with a charging branch that controls whether to charge the power lithium battery 2 via the second solenoid valve 9. When the output power of the fuel cell 3 is high, and the temperature of the fuel cell 3 exceeds the first set temperature, the aforementioned charging branch is activated to charge the power lithium battery 2. This increases the ways in which the output power of the fuel cell 3 is consumed, allowing the excess output power of the fuel cell 3, besides supplying a portion to the BOP, to be used for heat generation through the coil and for charging the power lithium battery 2. Therefore, compared to existing technologies, there is no need to limit the output power of the fuel cell 3, effectively improving the start-up efficiency of the fuel cell 3.
[0080] 3. When the temperature of the power lithium battery 2 is higher than the second set temperature, the second solenoid valve 9 is closed to charge the power lithium battery 2, so as to ensure the charging and use of the power lithium battery 2.
[0081] Example 3
[0082] An improvement upon Example 1 is made, wherein the magnetic conductor comprises a first magnetic conductor ring and a second magnetic conductor ring, such as... Figure 3 As stated above.
[0083] The first magnetic conductor ring and the second magnetic conductor ring both adopt a circular or polygonal ring structure with one end open (such as a square ring, rectangular ring, circular ring, regular hexagonal ring, regular octagonal ring, etc.), and each of them has an independently set energized coil with a different number of turns wound on one side surface of the ring structure.
[0084] The opening of the first magnetic conductor ring connects to the surface of the power lithium battery 2's casing, and the opening of the second magnetic conductor ring connects to the stack end plate of the fuel cell 3. Since the fuel cell 3 and the power lithium battery 2 are heated to different temperatures, two conductor rings with coils wound around them can be placed at opposite ends of the fuel cell 3 and the power lithium battery 2 respectively, allowing for separate control of the heating circuits and reducing the risk of the power lithium battery 2 overheating.
[0085] Preferably, the cryogenic start-up system further includes a second solenoid valve 9 and a third solenoid valve 12.
[0086] One end of the second solenoid valve 9 is connected to the output end of the DC-DC converter 4, and the other end is connected to the charging end of the power lithium battery 2, which is used to control the charging of the power lithium battery 2.
[0087] One end of the third solenoid valve 12 is connected to the output end of the DC-DC converter 4, and the other end is connected to the power input end of the energized coil on the first magnetic conductor ring, which is used to control whether to heat the power lithium battery 2.
[0088] One end of the first solenoid valve 7 is connected to the output terminal of the DC-DC converter 4, and the other end is connected to the power supply input terminal of the energized coil on the second magnetic conductor ring, which is used to control whether to heat the fuel cell 3.
[0089] Since the set heating temperatures of fuel cell 3 and power lithium battery 2 are different, they may not be heated to the set temperature at the same time. Therefore, based on embodiment 1, an optimization is made by adding a magnetic conductor with a wound coil to each end of fuel cell 3 and power lithium battery 2, so that the heating circuit is controlled separately and the risk of overheating of power battery is reduced.
[0090] Preferably, the low-temperature start-up system further includes a first temperature monitoring device 10 and a second temperature monitoring device 11.
[0091] The first temperature monitoring device 10 is installed in the external circulation loop of the coolant in the fuel cell 3 and is used to monitor the real-time temperature of the fuel cell 3.
[0092] The second temperature monitoring device 11 is installed on the surface of the casing of the power lithium battery 2 and is used to monitor the real-time temperature of the power lithium battery 2.
[0093] Preferably, the cryogenic start-up system further includes a controller 8.
[0094] The controller 8 is used to control the start-up of the fuel cell 3, and simultaneously close the first solenoid valve 7 and the third solenoid valve 12, and open the second solenoid valve 9; and, during the start-up process of the fuel cell 3, when the real-time data of the first temperature monitoring device 10 is detected to be greater than the first set temperature, the first solenoid valve 7 is opened (stopping the heating of the fuel cell 3 and switching parameters to start load), and when the real-time data of the second temperature monitoring device 11 is greater than the second set temperature, the second solenoid valve 9 is closed and the third solenoid valve 12 is opened (the power lithium battery 2 is no longer heated and begins to receive charging from the fuel cell 3).
[0095] The input terminals of the controller 8 are connected to the output terminals of the first temperature monitoring device 10 and the second temperature monitoring device 11, respectively, and its output terminals are connected to the control terminals of the fuel cell 3, the first solenoid valve 7, the second solenoid valve 9, and the third solenoid valve 12, respectively.
[0096] Preferably, the controller 8 executes the following program:
[0097] SS1. Upon receiving the low-temperature start-up control command for fuel cell 3, it controls the fuel cell 3 to start up, and simultaneously closes the first solenoid valve 7 and the third solenoid valve 12, and opens the second solenoid valve 9.
[0098] SS2. Periodically monitor whether the real-time data of the first temperature monitoring device 10 is greater than the first set temperature (generally set at a temperature between 50 and 70°C). If so, disconnect the first solenoid valve 7 and control the fuel cell 3 to switch to the load state. Otherwise, keep the first solenoid valve 7 closed and continue monitoring the real-time data of the first temperature monitoring device 10 in the next cycle.
[0099] SS3. Periodically monitor whether the real-time data of the second temperature monitoring device 11 is greater than the second set temperature (generally set between 5 and 40°C). If so, close the second solenoid valve 9, open the third solenoid valve 12, and return to step SS2 above. Otherwise, keep the second solenoid valve 9 in the open state and continue monitoring the real-time data of the second temperature monitoring device 11 in the next cycle.
[0100] Preferably, the controller 8 has a display module; and the display screen of the display module displays real-time data of the first temperature monitoring device 10 and the second temperature monitoring device 11 during the start-up process of the fuel cell 3.
[0101] Preferably, the magnetic conductor is made of one of the following materials: iron, cobalt, and nickel.
[0102] Preferably, both the first magnetic conductor opening and the second magnetic conductor opening have two oppositely arranged, parallel, and equal-area end faces to form a closed loop between the power lithium battery 2 / fuel cell 3 and the magnetic conductor. The resulting alternating magnetic field is confined within the area where the power lithium battery 2 / fuel cell 3 is located, reducing the risk of electromagnetic interference to other electrical components.
[0103] The two end faces of the second magnetic conductor opening are parallel to the plane containing the bipolar plate and membrane electrode in the fuel cell 3.
[0104] Preferably, the cryogenic start-up system further includes a fuel gas recirculation device.
[0105] The input end of the fuel gas circulation device is connected to the fuel gas exhaust outlet of the fuel cell 3, and the output end is connected to the fuel gas inlet of the fuel cell 3.
[0106] Compared with the prior art, this embodiment has the following beneficial effects:
[0107] 1. A typical hysteresis heating component 1 structure is provided, comprising two independent magnetic conductor rings, with an energized coil wound on each magnetic conductor ring. The opening of the first magnetic conductor ring is inserted into a power lithium battery 2 for heating the battery 2, and the generation of an alternating magnetic field is controlled by a first solenoid valve 7. The opening of the second magnetic conductor ring is inserted into a fuel cell 3 for heating the fuel cell 3, and the generation of an alternating magnetic field is controlled by a third solenoid valve 12. Both of these methods can effectively heat the fuel cell 3 and the power lithium battery 2.
[0108] 2. A second solenoid valve 9 is provided, along with a charging branch that controls whether to charge the power lithium battery 2 via the second solenoid valve 9. When the output power of the fuel cell 3 is high, and the temperature of the fuel cell 3 exceeds the first set temperature, the aforementioned charging branch is activated to charge the power lithium battery 2. This increases the ways in which the output power of the fuel cell 3 is consumed, allowing the excess output power of the fuel cell 3, besides supplying a portion to the BOP, to be used for heat generation through the coil and for charging the power lithium battery 2. Therefore, compared to existing technologies, there is no need to limit the output power of the fuel cell 3, effectively improving the start-up efficiency of the fuel cell 3.
[0109] 3. When the temperature of the power lithium battery 2 is higher than the second set temperature, the second solenoid valve 9 is closed and the third solenoid valve 12 is opened to charge the power lithium battery 2 and stop heating the power lithium battery 2, so as to ensure the safe charging and use of the power lithium battery 2.
[0110] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, and are not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical applications, or improvements to the prior art of the embodiments, or to enable others skilled in the art to understand the embodiments disclosed herein.
Claims
1. A cryogenic start-up system for a proton exchange membrane fuel cell, characterized in that, This includes a hysteresis heating component, a power lithium battery, a fuel cell, a DC-DC converter, a DC-AC converter, a frequency converter, and a first solenoid valve; among which, The hysteresis heating assembly includes a magnetic conductor and an energized coil wound around the magnetic conductor. The magnetic conductor has a first magnetic conductor opening for inserting a power lithium battery and a second magnetic conductor opening for inserting a fuel cell. The magnetic conductor includes a first magnetic conductor ring and a second magnetic conductor ring, wherein both the first and second magnetic conductor rings adopt a circular or polygonal ring structure with one end open, and an independently arranged energized coil with a different number of turns is wound on one side surface of the ring structure. The ring structure opening of the first magnetic conductor ring is connected to the surface of the power lithium battery casing, and the ring structure opening of the second magnetic conductor ring is connected to the fuel cell stack end plate. The first solenoid valve, the energized coil, and the frequency converter are connected in sequence to form a hysteresis effect generating circuit for generating an alternating magnetic field; the power output terminal of the fuel cell is connected to the electrical signal input terminal of the hysteresis effect generating circuit after passing through a DC-DC converter and a DC-AC converter in sequence. The fuel cell outputs alternating current through a DC-DC converter and a DC-AC converter. When the alternating current passes through the energized coil, it generates a magnetic field of the same frequency. The magnetic conductor then constructs an alternating magnetic field at both ends of the fuel cell and the power lithium battery. The magnetic conductor generates heat due to the hysteresis effect in the alternating magnetic field. Furthermore, the metal components in fuel cells and power lithium batteries spontaneously magnetize in a magnetic field to form many magnetic domain structures. The magnetic pole direction of the magnetic domains also changes with the direction of the magnetic field in an alternating magnetic field. When the magnetic pole direction of the magnetic domains changes, they will rub against the surrounding magnetic domains and generate heat.
2. The cryogenic start-up system for a proton exchange membrane fuel cell according to claim 1, characterized in that, The magnetic conductor is an H-type magnetic conductor; wherein... A power lithium battery is placed in the middle of the opening on one side of the H-shaped magnetic conductor, and a fuel cell is placed in the middle of the opening on the other side. An energized coil is wound on the magnetic conductor beam in the middle.
3. The cryogenic start-up system for a proton exchange membrane fuel cell according to claim 2, characterized in that, It also includes a second solenoid valve; wherein, One end of the second solenoid valve is connected to the output of the DC-DC converter, and the other end is connected to the charging terminal of the power lithium battery.
4. The cryogenic start-up system for a proton exchange membrane fuel cell according to claim 1, characterized in that, It also includes a third solenoid valve; among which, One end of the third solenoid valve is connected to the output terminal of the DC-DC converter, and the other end is connected to the power supply input terminal of the energized coil on the first magnetic conductor ring. One end of the first solenoid valve is connected to the output terminal of the DC-DC converter, and the other end is connected to the power input terminal of the energized coil on the second magnetic conductor ring.
5. The cryogenic start-up system for a proton exchange membrane fuel cell according to claim 3, characterized in that, Also includes: The first temperature monitoring device is located in the external circulation loop of the fuel cell's coolant and is used to monitor the real-time temperature of the fuel cell. The second temperature monitoring device is installed on the surface of the power lithium battery casing to monitor the real-time temperature of the power lithium battery.
6. The cryogenic start-up system for a proton exchange membrane fuel cell according to claim 5, characterized in that, Also includes: The controller is used to control the start-up of the fuel cell, and simultaneously close the first solenoid valve and open the second solenoid valve; and, during the start-up process of the fuel cell, when the real-time data of the first temperature monitoring device is detected to be greater than the first set temperature, the first solenoid valve is opened, and the second solenoid valve is closed when the real-time data of the second temperature monitoring device is greater than the second set temperature. The controller's input terminals are connected to the output terminals of the first temperature monitoring device and the second temperature monitoring device, respectively, and its output terminals are connected to the control terminals of the fuel cell, the first solenoid valve, and the second solenoid valve, respectively.
7. The cryogenic start-up system for a proton exchange membrane fuel cell according to claim 6, characterized in that, The controller executes the following program: Upon receiving the fuel cell low-temperature start-up control command, the system controls the fuel cell to start, simultaneously closing the first solenoid valve and opening the second solenoid valve. The system periodically monitors whether the real-time data of the first temperature monitoring device is greater than the first set temperature. If it is, the first solenoid valve is disconnected and the fuel cell is switched to the load state. Otherwise, the first solenoid valve is kept closed and the monitoring of the real-time data of the first temperature monitoring device continues in the next cycle. The system periodically monitors whether the real-time data of the second temperature monitoring device is greater than the second set temperature. If so, the system closes the second solenoid valve and returns to the previous step of periodically monitoring whether the real-time data of the first temperature monitoring device is greater than the first set temperature. Otherwise, the system maintains the open state of the second solenoid valve and continues monitoring the real-time data of the second temperature monitoring device in the next cycle.
8. The cryogenic start-up system for a proton exchange membrane fuel cell according to any one of claims 1, 2, 4, 5, 6, and 7, characterized in that, The magnetic conductor is made of one of the following materials: iron, cobalt, and nickel.
9. The cryogenic start-up system for a proton exchange membrane fuel cell according to any one of claims 1, 2, 4, 5, 6, and 7, characterized in that, Both the first magnetic conductor opening and the second magnetic conductor opening have two oppositely arranged, parallel end faces with equal areas; the aforementioned two end faces of the second magnetic conductor opening are parallel to the plane containing the bipolar plates and membrane electrodes in the fuel cell.