Battery single-low reason troubleshooting method

Abstract

The invention discloses a battery single low reason troubleshooting method, which comprises the following steps: when a single low phenomenon occurs in a to-be-detected electric pile, carrying out open circuit and short circuit troubleshooting on the to-be-detected electric pile; if the open circuit and short circuit checking indicates that the to-be-detected galvanic pile does not have the open circuit and short circuit problems, performing membrane electrode perforation checking on the to-be-detected battery; if the membrane electrode perforation checking indicates that the to-be-detected galvanic pile does not have the membrane electrode perforation problem, determining the single-low position of the to-be-detected galvanic pile; and checking the to-be-detected galvanic pile based on a checking strategy corresponding to the single low position. In the embodiment of the invention, whether the single low is caused by short circuit and open circuit is firstly judged, then whether the single low is caused by membrane electrode perforation is judged, specific troubleshooting processing is performed on other possible reasons according to the position of the single low, and corresponding processing can be performed according to different conditions by listing the troubleshooting priority for the severity and development speed of disaster consequences caused by the single low reasons; the method is helpful for quickly judging the low-order reason and preventing the serious consequence of the low-order condition.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fuel cells, in particular to a battery single low cause investigation method. BACKGROUND

[0002] Proton exchange membrane fuel cells have extremely broad application prospects in the fields of new energy automobile power sources and distributed fixed power stations due to their high energy conversion efficiency, low working temperature, fast start-up speed, zero emission and no pollution and other outstanding advantages.

[0003] As the core power generation unit of a fuel cell, a fuel cell stack is usually composed of hundreds of single cells stacked in series. In actual operation, the performance voltage of individual single cells in the stack is significantly lower than that of other normal single cells, that is, single low phenomenon, which is a common and serious fault mode. The initial harm of the single low phenomenon is to directly cause the output voltage and power of the entire stack to drop, affecting the performance of the power system. If it is not diagnosed and treated in time, the performance of the faulty battery will continue to deteriorate, causing a chain reaction, resulting in the entire system being unable to work, and even causing catastrophic safety accidents such as fire and explosion. SUMMARY

[0004] In order to solve the existing technical problems, the present application provides a battery single low cause investigation method. First, it is judged whether the single low is caused by short circuit or open circuit. Secondly, it is judged whether it is caused by membrane electrode perforation. Other possible causes have a low risk development speed, and can be treated according to specific different situations. According to the single low position, specific investigation and treatment are carried out. By listing the investigation priority according to the severity and development speed of the disaster caused by the single low cause, different situations can be treated accordingly, which helps to quickly judge the single low cause and prevent the single low situation from causing serious consequences.

[0005] In the first aspect, the embodiments of the present application provide a battery single low cause investigation method, which comprises: When the single low phenomenon occurs in the to-be-detected stack, the open circuit and short circuit investigation of the to-be-detected stack is carried out; If the open circuit and short circuit investigation indicates that the to-be-detected stack does not have open circuit and short circuit problems, the membrane electrode perforation investigation of the to-be-detected battery is carried out; If the membrane electrode perforation investigation indicates that the to-be-detected stack does not have membrane electrode perforation problems, the single low position of the to-be-detected stack is determined; The to-be-detected stack is investigated based on the investigation strategy corresponding to the single low position.

[0006] In an optional embodiment, the to-be-detected stack is investigated based on the investigation strategy corresponding to the single low position, which comprises: If the single low position is the middle position of the stack, the to-be-detected stack is investigated based on the first investigation strategy; The first troubleshooting strategy is used to troubleshoot the battery of the to-be-tested stack.

[0007] In an optional embodiment, the to-be-tested stack is further subjected to the troubleshooting based on the troubleshooting strategy corresponding to the single-low position. If the single-low position is the stack inlet and outlet position, the to-be-tested stack is subjected to the troubleshooting based on the second troubleshooting strategy. If the second troubleshooting strategy indicates that the to-be-tested stack has no non-battery problem, the to-be-tested stack is subjected to the troubleshooting based on the first troubleshooting strategy.

[0008] In an optional embodiment, if the single-low position is the stack inlet and outlet position, the to-be-tested stack is subjected to the troubleshooting based on the second troubleshooting strategy, which includes: If the single-low position is the stack inlet and outlet position, the hydrogen inlet concentration and liquid water are subjected to the troubleshooting. If the hydrogen inlet concentration and liquid water troubleshooting indicates that the inlet gas is unqualified or the liquid water is excessive, the starting condition of the drainage scavenging system is detected, the inlet and outlet gas flow and the generated water amount are analyzed, the hydrogen or air inlet flow is increased, and the single-low reason of the to-be-tested stack is determined based on the inlet and outlet gas flow and the generated water amount. If the hydrogen inlet concentration and liquid water troubleshooting indicates that the inlet gas is qualified and the liquid water is normal, and the single-low condition is still not alleviated even if the gas flow is increased, the temperature distribution and voltage distribution at different positions are subjected to the troubleshooting. If the temperature distribution and voltage distribution at different positions troubleshooting indicates that the temperature distribution is uneven, the local temperature is too high, or the voltage distribution at different positions is uneven, the assembly record during the assembly of the stack is checked, the single cell where the single-low phenomenon occurs is subjected to X-ray detection, and whether the single-low reason of the to-be-tested stack is the deformation of the single cell is determined based on the assembly record and the X-ray detection. If the temperature and voltage troubleshooting indicates that the temperature distribution is normal and the voltage distribution is uniform, it is determined that the to-be-tested stack has no non-battery problem.

[0009] In an optional embodiment, if the single-low position is the middle position of the stack, the to-be-tested stack is subjected to the troubleshooting based on the first troubleshooting strategy, which includes: If the single-low position is the middle position of the stack, the to-be-tested stack is subjected to the generated water troubleshooting, and the PH value of the generated water and the substance composition of the generated water are obtained. The single-low reason of the to-be-tested stack is determined based on the PH value and the substance composition.

[0010] In an optional embodiment, if the open circuit and short circuit troubleshooting indicates that the to-be-tested stack has no open circuit and short circuit problem, the membrane electrode perforation of the to-be-tested battery is subjected to the troubleshooting, which includes: If the open circuit and short circuit troubleshooting indicates that the to-be-tested stack has no open circuit and short circuit problem, hydrogen is supplied to the anode of the to-be-tested battery, and air is supplied to the cathode of the to-be-tested battery. detecting a first open circuit voltage of the battery to be detected; if the first open circuit voltage is abnormal, determining that the battery to be detected has a membrane electrode perforation problem.

[0011] In an alternative embodiment, after detecting the first open circuit voltage of the battery to be detected, further comprising: if the first open circuit voltage is normal, increasing the hydrogen pressure of the anode; detecting a second open circuit voltage of the battery to be detected; if the second open circuit voltage is abnormal, determining that the battery to be detected has a membrane electrode perforation problem; or if the second open circuit voltage is normal, determining that the battery to be detected does not have a membrane electrode perforation problem.

[0012] In an alternative embodiment, the open circuit and short circuit troubleshooting includes inspection of the patrol pointer, inspection of the double pole plate edge curling, and inspection of the foreign matter inclusion of the electric pile.

[0013] In an alternative embodiment, when the single low phenomenon occurs in the electric pile to be detected, after the open circuit and short circuit troubleshooting of the electric pile to be detected, further comprising: if the open circuit and short circuit troubleshooting indicates that the electric pile to be detected has an open circuit and short circuit problem, rectifying the open circuit and short circuit problem of the electric pile to be detected.

[0014] In an alternative embodiment, when the single low phenomenon occurs in the electric pile to be detected, after the open circuit and short circuit troubleshooting of the electric pile to be detected, further comprising: if the membrane electrode perforation troubleshooting indicates that the electric pile to be detected has a membrane electrode perforation problem, replacing the membrane electrode of the electric pile to be detected.

[0015] The battery single low cause troubleshooting method provided by the embodiments of the present application has the following technical effects: When the single low phenomenon occurs in the electric pile to be detected, the open circuit and short circuit troubleshooting of the electric pile to be detected is performed; if the open circuit and short circuit troubleshooting indicates that the electric pile to be detected does not have an open circuit and short circuit problem, the membrane electrode perforation troubleshooting of the battery to be detected is performed; if the membrane electrode perforation troubleshooting indicates that the electric pile to be detected does not have a membrane electrode perforation problem, the single low position of the electric pile to be detected is determined; and the electric pile to be detected is troubleshooted based on the troubleshooting strategy corresponding to the single low position. In the embodiments of the present application, it is first determined whether the single low is caused by short circuit and open circuit, and then it is determined whether it is caused by membrane electrode perforation. Other possible causes have a low risk development speed, and can be processed according to specific different situations. The specific troubleshooting and processing are targeted according to the single low position. The troubleshooting priority is listed according to the severity and development speed of the disaster consequences caused by the single low cause. Different situations can be processed accordingly, which helps to quickly determine the single low cause and prevent the single low situation from causing serious consequences. BRIEF DESCRIPTION OF DRAWINGS

[0016] To more clearly illustrate the technical solutions and advantages in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating a method for troubleshooting low battery levels provided in an embodiment of this application. Figure 1 ; Figure 2 This is a flowchart illustrating a method for troubleshooting low battery levels provided in an embodiment of this application. Figure 2 ; Figure 3 This is a flowchart illustrating a second screening strategy provided in an embodiment of this application; Figure 4 This is a flowchart illustrating a first screening strategy provided in an embodiment of this application; Figure 5 This is a flowchart illustrating a method for troubleshooting perforations in a membrane electrode according to an embodiment of this application. Detailed Implementation

[0018] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0019] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or server that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0020] The following describes a specific embodiment of a method for troubleshooting low battery voltage according to this application. Figure 1This is a flowchart illustrating a method for troubleshooting low battery levels according to an embodiment of this application. This specification provides the method operation steps as shown in the embodiments or flowcharts, but based on conventional or non-inventive methods, more or fewer operation steps may be included. The order of steps listed in the embodiments is merely one possible execution order among many steps and does not represent the only possible execution order. Specifically, as shown... Figure 1 As shown, it may include: S101: When a single low voltage phenomenon occurs in the fuel cell stack under test, the open circuit and short circuit of the fuel cell stack under test shall be checked.

[0021] In this embodiment of the application, the troubleshooting of open circuits and short circuits includes troubleshooting various simple factors that affect gas flow, electron and proton transfer, such as checking the inspection pointer, checking the bipolar plate edge curling, and checking for foreign matter inclusions in the fuel cell stack.

[0022] S102: Determine if there are open circuit or short circuit problems. If yes, proceed to S103; otherwise, proceed to S107.

[0023] S103: Rectify the open circuit and short circuit issues of the fuel cell stack to be tested.

[0024] S104: Inspect the membrane electrode perforation of the battery under test.

[0025] Optionally, if open circuit and short circuit problems exist, rectify the open circuit and short circuit problems of the stack to be tested; if there are no open circuit and short circuit problems, check the membrane electrode perforation of the battery to be tested.

[0026] In one possible embodiment, visual inspection is used to check for open or short circuits. This primarily involves visually inspecting the voltage probes. The voltage probes are a dense array of tiny metal probes used to contact the current collector of each individual cell to measure voltage. Improper installation of the probe harness, resulting in tensile stress, can cause some probes to retract or bend, preventing proper contact with the current collector. If the harness is not tightly bound or improperly laid out, adjacent probes may accidentally touch each other. Therefore, visually inspecting the probes specifically involves checking whether, after the fuel cell stack is assembled, tensile stress in the probe harness leads to poor contact or probes touching each other, causing an open or short circuit.

[0027] In one possible embodiment, troubleshooting open or short circuits also includes visually inspecting for bipolar plate curling issues. During assembly, uneven stress or shear forces can cause plastic warping or curling of the sealing or flow field areas at the edges of the metal bipolar plates. This curled portion may directly contact adjacent bipolar plates. The curled bipolar plates create a direct, low-resistance conductive path between two normally insulated single cells. A short circuit point can experience a huge current flow, leading to a rapid local temperature rise. This not only accelerates the aging of the membrane electrode but also directly lowers the voltage of the single cell, causing low voltage. Therefore, visual inspection is crucial to identify instances where the metal bipolar plates curl and come into contact during assembly due to external forces, resulting in short circuits.

[0028] In one possible embodiment, troubleshooting open or short circuits also includes visually inspecting for foreign object inclusions. During the assembly of the fuel cell stack, tiny metal shavings, tool fragments, or other conductive impurities scraped from screws may accidentally fall between individual cells. Conductive foreign objects sandwiched between two layers of bipolar plates can also form a conductive bridge, leading to a local short circuit. Therefore, a visual inspection is conducted to check for foreign object inclusions on the fuel cell stack that may cause short circuits.

[0029] If, after thorough investigation, any of the above-mentioned causes of the short circuit are identified, corresponding corrective measures should be taken to restore normal operation. These are just a few simple examples; other similar factors that could potentially cause a short circuit or open circuit should also be investigated. If, after thorough investigation, it is determined that the above causes are not the cause, proceed to the next step: investigating membrane electrode perforation.

[0030] By following the steps above, the first step is to check whether the low battery level is caused by a short circuit or open circuit. This helps prevent serious accidents such as fires caused by short circuits, which could damage the entire battery pack or even lead to explosions and significant economic losses. The disastrous consequences of this single low battery level can occur rapidly and must be investigated as quickly and prioritized.

[0031] S105: Determine if there is a membrane electrode perforation problem. If yes, proceed to S106; otherwise, proceed to S107.

[0032] S106: Replace the membrane electrode of the stack to be tested.

[0033] S107: Determine the single low position of the fuel cell stack to be tested.

[0034] S108: The troubleshooting strategy based on the single low position is used to troubleshoot the fuel cell stack under test.

[0035] In one possible embodiment, if the membrane electrode perforation investigation indicates that the stack under test has a membrane electrode perforation problem, the membrane electrode of the stack under test is replaced.

[0036] In another possible embodiment, if the membrane electrode perforation investigation indicates that the stack under test does not have a membrane electrode perforation problem, the single low position of the stack under test is determined, and the stack under test is investigated based on the investigation strategy corresponding to the single low position.

[0037] If membrane electrode perforation is not investigated promptly, it can lead to serious consequences such as membrane electrode damage. Therefore, after checking for short circuits and open circuits, membrane electrode perforation should be investigated. Other possible causes of danger develop at a slower rate, and can be addressed according to specific circumstances.

[0038] Figure 2 This is a flowchart illustrating a method for troubleshooting low battery levels provided in an embodiment of this application. Figure 2 The method may include: S201: Determine if the single low position is the middle position of the fuel cell stack. If yes, execute S202; otherwise, execute S203.

[0039] In the embodiments of this application, for a battery stack experiencing a single low battery phenomenon, there may be three situations: a single low battery at the battery stack inlet, a single low battery in the middle of the battery stack, and a single low battery at the battery stack outlet (far end).

[0040] In one possible embodiment, the fuel cell inlet first comes into contact with the reaction gases and coolant from external systems such as the hydrogen system and air system. The main cause of low efficiency is the instability or impact of external inputs.

[0041] In one possible embodiment, a low cell depth in the middle of the stack typically indicates intrinsic performance degradation or manufacturing defects in that single cell.

[0042] In one possible embodiment, the fuel cell outlet is the endpoint of the flow of reactant gases and coolant, the region with the slowest flow rate, the greatest likelihood of material accumulation, the highest mechanical pressure, and the greatest likelihood of deformation.

[0043] S202: Investigate the fuel cell stack under test based on the first investigation strategy.

[0044] In one possible embodiment, the first screening strategy instructs the batteries of the stack to be tested to be screened.

[0045] S203: Investigate the fuel cell stack under test based on the second investigation strategy.

[0046] In one possible embodiment, the second investigation strategy instructs the investigation of non-battery issues in the stack under test.

[0047] S204: Determine if there is a non-battery problem. If yes, proceed to S206; otherwise, proceed to S205.

[0048] S205: Investigate the fuel cell stack under test based on the first investigation strategy.

[0049] S206: Rectify non-battery issues.

[0050] In one optional embodiment, if the single low position is in the middle of the battery stack, the main reason for the single low position in the middle of the battery stack may be a problem with the battery itself or the anode and cathode being installed in reverse. Therefore, the battery stack to be tested is investigated based on the first investigation strategy, specifically the battery of the battery stack to be tested is investigated.

[0051] In one optional embodiment, if the single low position is the inlet / outlet position of the fuel cell stack, the main reason for the single low position at the fuel cell stack inlet / outlet may be a problem with the hydrogen supply system, etc. Therefore, the fuel cell stack under test is investigated based on the second investigation strategy, specifically investigating non-battery problems of the fuel cell stack under test. If the second investigation strategy indicates that there are no non-battery problems in the fuel cell stack under test, the fuel cell stack under test is investigated based on the first investigation strategy, specifically investigating the batteries of the fuel cell stack under test.

[0052] By implementing the above settings and adopting differentiated troubleshooting strategies based on the location of the low-temperature phenomenon, the core suspected area can be quickly identified, significantly shortening the troubleshooting time and improving maintenance efficiency.

[0053] Figure 3 This is a flowchart illustrating a second screening strategy provided in an embodiment of this application. In one optional embodiment, if the single low position is the inlet / outlet position of the fuel cell stack, the fuel cell stack to be tested is screened based on the second screening strategy, including: S2031: Conduct an investigation into the concentration of hydrogen gas entering the system and the inflow of liquid water.

[0054] In one possible embodiment, the phenomenon of low battery density at the battery stack inlet is mainly due to the following reasons: foreign matter mixed in at the battery stack inlet; water flowing into the battery stack inlet; and a sudden change in the area of ​​the three cavities at the battery stack inlet.

[0055] Foreign matter entering the fuel cell stack inlet may include solid particles such as metal shavings, dust, and fragments of sealing material brought in by external pipes, air compressors, hydrogen circulation pumps, or gas cylinders. These foreign objects are carried into the stack by the airflow and first reach the first few individual cells at the inlet. These particles may block the inlet of the bipolar plate flow channel of that individual cell or become stuck on the surface of the gas diffusion layer. Flow channel blockage will severely hinder the distribution of reactant gases such as hydrogen or air to the entire reaction area of ​​the individual cell. Insufficient supply of reactant gases will cause severe concentration polarization, resulting in a rapid drop in the voltage of that individual cell, manifested as a low voltage phenomenon at the stack inlet.

[0056] Water flows in at the inlet of the fuel cell stack. Liquid water will rush into the flow channel of the single cell instantly. The water will quickly flood the flow channel and may invade the porous gas diffusion layer. After the gas diffusion layer is filled with water, the reacting gas cannot penetrate the water film to reach the catalyst layer. The chemical reaction is forcibly interrupted, causing the single low phenomenon at the inlet of the fuel cell stack.

[0057] The sudden change in the area of ​​the three chambers at the fuel cell stack inlet refers to the sudden expansion or contraction of the three independent chambers supplying hydrogen, air, and coolant, resulting in a single low-temperature phenomenon at the fuel cell stack inlet.

[0058] In one possible embodiment, the following three special cases exist at the far end of the fuel cell stack (also known as the blind end): a large amount of liquid water tends to accumulate at the far end of the fuel cell stack; the amount of gas and cooling water is minimal at the far end; the assembly pressure is greatest at the far end; and the deformation of a single cell is greatest at the blind end.

[0059] The accumulation of large amounts of liquid water at the far end of the fuel cell stack is due to the fact that water generated by the electrochemical reaction and moisture introduced by the reaction gases move towards the fuel cell stack outlet with the airflow. During the flow, water vapor condenses into liquid water due to the temperature drop. Since the flow velocity at the far end is the lowest, it is not possible to effectively blow away the liquid water. The accumulated liquid water will block the flow channel, severely hindering the diffusion of reaction gases to the catalyst layer, causing severe concentration polarization. This leads to a voltage drop in the far-end single cell due to the lack of air as a reaction gas, forming the single low voltage phenomenon at the far end of the fuel cell stack.

[0060] The gas and cooling water flow is minimal at the far end because hydrogen and air are continuously consumed by the individual cells at the front as they flow through the entire stack. Therefore, the concentration and partial pressure of the reactant gases are lowest when they reach the far end. The coolant absorbs heat as it flows through the stack, and its temperature gradually increases, which may also lead to a relatively low flow rate at the far end, resulting in the low flow rate at the far end of the stack.

[0061] During the press-fitting of the fuel cell stack, pressure is applied by end plates at both ends. Due to the minute frictional forces and compressive deformation between the components, the pressure is not completely uniform as it is transmitted from the end plates to the center, and a certain pressure gradient usually exists. This means that the mechanical clamping force actually borne by the farthest cells may be slightly higher than that of the middle cells. Excessive pressure can significantly reduce the porosity of the gas diffusion layer, affecting gas diffusion and drainage. Excessive pressure may also cause micro-deformation of the flow channels in the thin metal bipolar plates, affecting the flow cross-sectional area, thereby leading to performance degradation and low-performance cells at the far ends of the stack.

[0062] Therefore, in this embodiment of the application, the investigation of hydrogen intake concentration and inflow liquid water specifically involves checking whether the hydrogen intake concentration is normal, checking whether the intake is unqualified or mixed with too much inflow liquid water, checking the hydrogen supply system and hydrogen source, and checking whether there is any liquid water residue at the battery intake.

[0063] S2032: Determine if the air intake is not up to standard or if there is too much liquid water. If yes, proceed to S2033; otherwise, proceed to S2034.

[0064] S2033: Detect the start-up status of the drainage and scavenging system, analyze the intake and exhaust flow rates and the amount of water generated, increase the hydrogen or air intake flow rate, and determine the cause of the single low temperature of the fuel cell stack under test based on the intake and exhaust flow rates and the amount of water generated.

[0065] S2034: Investigate temperature distribution and voltage distribution at different locations.

[0066] In one optional embodiment, if the hydrogen intake concentration and liquid water discharge indication are unqualified or there is too much liquid water, the activation status of the drainage and scavenging system is checked, the intake and exhaust flow rates and the amount of water generated are analyzed, and the hydrogen or air intake flow rate can be increased as appropriate. Based on the intake and exhaust flow rates and the amount of water generated, the cause of the single low level of the fuel cell stack under test is determined.

[0067] In this case, if the intake air is not up to standard, it can be considered that there is a problem with the hydrogen intake concentration and the flow of liquid water. If there is too much liquid water, it can also be considered that there is a problem with the hydrogen intake concentration and the flow of liquid water. If the intake air is not up to standard and there is too much liquid water, it can also be considered that there is a problem with the hydrogen intake concentration and the flow of liquid water.

[0068] If there is too much residual liquid water, it may be caused by two reasons: one is that too much liquid water is generated, and the other is that too little liquid water is discharged. Therefore, checking the start-up status of the drainage and scavenging system can accurately determine the specific cause of the low battery level and make further rectifications accordingly.

[0069] Specifically, inspecting the scavenging system includes checking whether the opening frequency and duration of the drain valve are normal, and whether the scavenging strategy is being executed as designed. Analyzing the inlet and outlet flow rates involves comparing the inlet and outlet flow rates of hydrogen to determine whether the circulation and discharge are unobstructed. Analyzing the amount of water generated involves theoretically calculating the amount of reaction water that should be produced based on the current and time of the fuel cell stack operation.

[0070] By comparing the test data with the theoretical value, the problem can be accurately located. If the actual water production is much greater than the theoretical value, it indicates that the excessive water production is caused by a problem with the system's operating status. In this case, the corresponding rectification direction is to check the system load and operating conditions. If the insufficient water discharge is caused by an abnormal operation of the drainage and scavenging system, the corresponding rectification direction is to repair or optimize the drainage and scavenging system.

[0071] In another optional embodiment, if the hydrogen intake concentration and liquid water check indicate that the intake is qualified and the liquid water is normal, the temperature distribution and voltage distribution at different locations are checked.

[0072] Specifically, temperature checks can be conducted by using an infrared thermal imager to non-contactly scan the surface of the operating fuel cell stack to obtain a complete temperature distribution map. This allows for analysis of the uniformity of the overall temperature distribution of the stack, identification of localized hot spots, and detection of any instances of excessively high local temperatures. Ideally, the temperature distribution of a fuel cell should be uniform; localized overheating indicates abnormal heat generation in that area.

[0073] Specifically, voltage checks involve using a multimeter to read the voltage values ​​at different locations of a single cell in real time, identifying whether the voltage distribution of a single low-voltage cell is uniform, and observing whether the voltage fluctuates drastically.

[0074] S2035: Determine if the temperature is too high or the voltage distribution is abnormal. If yes, proceed to S2036; otherwise, proceed to S2037.

[0075] Among them, excessively high temperature can be considered as a problem with temperature and voltage troubleshooting, abnormal voltage distribution can also be considered as a problem with temperature and voltage troubleshooting, and excessively high temperature and abnormal voltage can also be considered as a problem with temperature and voltage troubleshooting.

[0076] If there is excessively high temperature or abnormal voltage distribution, it points to an acute, thermoelectric-related physical fault. Subsequent X-ray inspection and review of assembly records are necessary to rule out physical problems such as deformation or short circuits. If the temperature and voltage distribution are uniform and there are no other abnormalities, it points to a chronic, chemical-level performance degradation or contamination. Subsequent analysis of the generated water composition is required to rule out chemical problems such as ion contamination.

[0077] S2036: Inspect the assembly records during the assembly of the fuel cell stack, perform X-ray inspection on the single cell that has a single low temperature phenomenon, and determine the cause of the single low temperature of the fuel cell stack under test based on the assembly records and X-ray inspection.

[0078] In one possible embodiment, checking the stack assembly records is to look for potential problems that may have occurred during assembly. This check might specifically include examining issues with the individual cells themselves, such as excessive hydrogen-space leakage at the membrane electrode assembly (MEA). During stack assembly, compression could exacerbate this leakage, potentially causing perforation of the MEA. Alternatively, it could be due to issues with the thickness of the carbon paper used to attach the MEA. Since carbon paper manufacturing can result in thickness variations, assembling MEAs made from carbon paper with thicknesses that are either too high or too low could lead to excessive or insufficient compression ratios, resulting in low single-cell performance.

[0079] In one possible embodiment, the assembly record check may also include checking the final height and parallelism. Height deviation indicates improper clamping force, and parallelism deviation indicates that the two ends of the fuel cell stack are not parallel and the internal stress distribution is seriously uneven. Therefore, it is necessary to check whether the final height of the fuel cell stack after pressing meets the requirements and the parallelism of the upper and lower end plates. If the height deviation or parallelism exceeds the tolerance, it will lead to uneven internal stress distribution of the fuel cell stack.

[0080] In one possible embodiment, assembly record checks may also include checking the initial voltage data of individual cells. The initial voltage data of individual cells characterizes the open-circuit voltage and operating voltage data of all individual cells when the stack is first assembled and tested for the first time. Under normal circumstances, the voltage values ​​of all individual cells are very uniform with very small differences, usually in the millivolt range. Therefore, if the faulty individual cell performs normally initially, it indicates that the individual cell may have experienced a performance degradation due to test conditions during operation.

[0081] In one possible embodiment, the assembly record check may also include checking the airtightness test record, which records whether the leakage rate of the hydrogen cavity, air cavity, and water cavity during assembly is up to standard. Minor leaks may worsen after long-term operation, causing insufficient reaction gas in a single cell. Checking the initial record can determine whether the leak was caused by poor sealing during assembly or a new problem that appeared after operation.

[0082] In the embodiments of this application, X-ray inspection can provide direct, non-destructive internal imaging evidence that can verify problems inferred from assembly records.

[0083] For example, if X-ray inspection reveals significant curling or deformation of the bipolar plate outside the visual inspection range, it indicates that the structure was damaged due to external impact or stress concentration during assembly. If the assembly record shows uneven initial single-voltage distribution, and X-ray inspection reveals obvious foreign objects in the flow channel, it indicates a failure in cleanliness control; the foreign objects were introduced during operation or assembly. If X-ray inspection reveals abnormal water distribution in the flow channel, indicating flooding, it suggests a possible mismatch in operating conditions, requiring adjustment. If the assembly record shows the initial airtightness test value is at the boundary, and X-ray inspection reveals abnormal seal position or deformation, it indicates poor seal installation or defects, leading to chronic leakage and worsening.

[0084] S2037: Confirm that there are no non-battery issues with the stack under test.

[0085] In one alternative embodiment, if the temperature and voltage check indicates that the temperature is too high or the voltage is abnormal, the assembly record during the stack assembly is checked, and the single cell with the single low temperature phenomenon is subjected to X-ray inspection. Based on the assembly record and X-ray inspection, the cause of the single low temperature of the stack under test is determined.

[0086] In another alternative embodiment, if the temperature and voltage checks indicate that the temperature distribution is normal and the voltage distribution is uniform, it is determined that the stack under test does not have any non-battery problems.

[0087] Figure 4 This is a flowchart illustrating a first screening strategy provided in an embodiment of this application. The method may include: S301: Investigate the generated water in the fuel cell stack under test, and obtain the pH value and composition of the generated water.

[0088] S302: Determine the cause of a single low pH value in the fuel cell stack under test based on pH value and material composition.

[0089] In the embodiments of this application, the reason for the single low voltage phenomenon in the middle part of the stack is mainly due to the battery itself. The voltage loss of a single cell mainly includes the following three aspects: ohmic polarization loss, activation polarization loss, and concentration polarization loss. Ohmic polarization loss usually refers to the increased resistance to the transport of protons and electrons in the battery, resulting in increased IR loss. Activation polarization loss usually refers to the energy consumed in maintaining the normal progress of the electrochemical reaction and driving the directional movement of electrons / protons. Increasing the catalyst activity or temperature can help reduce this energy barrier. Concentration polarization loss usually refers to the voltage loss caused by insufficient reaction gas intake to the catalyst layer in the battery.

[0090] In one possible embodiment, the generated water is normally weakly acidic. A significant decrease in pH indicates increased corrosion of components such as the bipolar plates, releasing more hydrogen ions and causing an abnormal pH. The presence of specific metal ions, such as iron, chromium, and nickel, in the generated water can be detected using instruments such as ion chromatography.

[0091] Internal battery dissolution is an irreversible form of damage. Therefore, after analyzing the pH value and material composition, it is determined whether the problem is caused by internal battery dissolution. If it is, the battery exhibiting the low pH phenomenon should be replaced directly.

[0092] Figure 5 This is a flowchart illustrating a method for troubleshooting membrane electrode perforations provided in an embodiment of this application. The method may include: S401: Pass hydrogen gas to the anode of the battery under test and pass air gas to the cathode of the battery under test.

[0093] S402: Detects the first open-circuit voltage of the battery under test.

[0094] S403: Determine if the first open-circuit voltage is normal. If yes, execute S405; otherwise, execute S406.

[0095] S404: The battery under test has been found to have a membrane electrode perforation problem.

[0096] S405: Increase the hydrogen pressure at the anode.

[0097] In one alternative embodiment, if the first open-circuit voltage is abnormal and drops rapidly, it is determined that the battery under test has a membrane electrode perforation problem, and if the problem is serious, the test should be stopped immediately.

[0098] In another optional embodiment, if the first open-circuit voltage is normal, the hydrogen pressure at the anode is increased, and the second open-circuit voltage after the increase in hydrogen pressure is detected. In this embodiment, the hydrogen side can be subjected to a pressure 20 kPa higher than the air side, and the second open-circuit voltage after the increase in hydrogen pressure can be observed.

[0099] S406: Determine if the second open-circuit voltage is normal. If yes, proceed to S408; otherwise, proceed to S407.

[0100] S407: The battery under test has been found to have a membrane electrode perforation problem.

[0101] S408: Confirmed that the battery under test does not have membrane electrode perforation issues.

[0102] In one optional embodiment, if the second open-circuit voltage is abnormal and drops rapidly, it indicates that there are micropores on the membrane electrode, confirming that the battery under test has a membrane electrode perforation problem.

[0103] In another alternative embodiment, if the second open-circuit voltage is normal, it is determined that the battery under test does not have a membrane electrode perforation problem.

[0104] As can be seen from the embodiments of the battery single-low-temperature cause investigation method provided in this application, when a single-low-temperature phenomenon occurs in the battery stack under test, the battery stack under test is checked for open circuit and short circuit; if the open circuit and short circuit investigation indicates that there is no open circuit or short circuit problem in the battery stack under test, the battery stack under test is checked for membrane electrode perforation; if the membrane electrode perforation investigation indicates that there is no membrane electrode perforation problem in the battery stack under test, the location of the single-low-temperature phenomenon in the battery stack under test is determined; and the battery stack under test is investigated based on the investigation strategy corresponding to the location of the single-low-temperature phenomenon. In the embodiments of this application, it is first determined whether the single-low-temperature phenomenon is caused by short circuit or open circuit, and then it is determined whether it is caused by membrane electrode perforation. Other possible causes have a lower risk development speed and can be dealt with according to different situations. Specifically, the investigation and treatment are targeted according to the location of the single-low-temperature phenomenon. By listing the investigation priority according to the severity and development speed of the disastrous consequences caused by the single-low-temperature phenomenon, it is possible to deal with different situations accordingly, which helps to quickly determine the cause of the single-low-temperature phenomenon and prevent the single-low-temperature phenomenon from causing serious consequences.

[0105] It should be noted that the order of the embodiments described above is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, specific embodiments have been described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims can be performed in a different order than that shown in the embodiments and still achieve the desired result. Additionally, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0106] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the device embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0107] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.

[0108] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for troubleshooting low battery voltage, characterized in that, include: When a single low voltage phenomenon occurs in the fuel cell stack under test, the open circuit and short circuit of the fuel cell stack under test should be checked. If the open circuit and short circuit troubleshooting indicates that the stack under test does not have open circuit or short circuit problems, the membrane electrode perforation troubleshooting is performed on the battery under test. If the membrane electrode perforation investigation indicates that the stack under test does not have a membrane electrode perforation problem, then determine the single low position of the stack under test; The investigation strategy corresponding to the single low position is used to investigate the fuel cell stack to be tested.

2. The method for troubleshooting low battery voltage according to claim 1, characterized in that, The investigation strategy based on the single low position for investigating the fuel cell stack to be tested includes: If the single low position is the middle position of the fuel cell stack, the fuel cell stack to be tested is investigated based on the first investigation strategy; The first investigation strategy instructs the batteries of the stack to be tested to be investigated.

3. The method for troubleshooting low battery voltage according to claim 2, characterized in that, The method of investigating the fuel cell stack under test based on the single low position also includes: If the single low position is the inlet / outlet position of the fuel cell stack, the fuel cell stack to be tested is investigated based on the second investigation strategy; If the second investigation strategy indicates that the stack under test does not have non-battery problems, the stack under test is investigated based on the first investigation strategy.

4. The method for troubleshooting low battery levels according to claim 3, characterized in that, If the single low position is the inlet / outlet position of the fuel cell stack, the fuel cell stack to be tested is investigated based on the second investigation strategy, including: If the single low position is the inlet / outlet position of the fuel cell stack, check the hydrogen intake concentration and the inflow of liquid water; If the hydrogen intake concentration and liquid water discharge indicator are not up to standard or there is too much liquid water, check the start-up status of the drainage and scavenging system, analyze the intake and exhaust flow rates and the amount of water generated, increase the hydrogen or air intake flow rate, and determine the cause of the single low level of the fuel cell stack under test based on the intake and exhaust flow rates and the amount of water generated. If the hydrogen intake concentration and liquid water check indicate that the intake is qualified and the liquid water is normal, and increasing the gas flow rate still does not alleviate the low situation, then check the temperature distribution and voltage distribution at different locations. If the temperature and voltage at different locations indicate uneven temperature distribution, with localized excessively high temperatures or uneven voltage distribution at different locations, check the assembly records during the stack assembly, perform X-ray inspection on the single cell exhibiting the single low temperature phenomenon, and determine whether the single low temperature of the stack under test is due to deformation of the single cell based on the assembly records and the X-ray inspection. If the temperature and voltage checks indicate that the temperature distribution and voltage distribution are normal, it is determined that the stack under test does not have the non-battery problem.

5. The method for troubleshooting low battery voltage according to claim 2, characterized in that, If the single low position is the middle position of the fuel cell stack, the fuel cell stack to be tested is investigated based on the first investigation strategy, including: If the single low position is the middle position of the fuel cell stack, the generated water of the fuel cell stack to be tested is investigated to obtain the pH value and composition of the generated water. The cause of the low pH value of the fuel cell stack under test is determined based on the pH value and the composition of the substance.

6. The method for troubleshooting low battery voltage according to claim 1, characterized in that, If the open circuit and short circuit troubleshooting indicates that the stack under test does not have open circuit or short circuit problems, the membrane electrode perforation troubleshooting is performed on the battery under test, including: If the open circuit and short circuit troubleshooting indicates that the battery stack under test does not have open circuit or short circuit problems, hydrogen gas is introduced into the anode of the battery under test and air is introduced into the cathode of the battery under test. Detect the first open-circuit voltage of the battery under test; If the first open-circuit voltage is abnormal, it is determined that the battery under test has a membrane electrode perforation problem.

7. The method for troubleshooting low battery voltage according to claim 6, characterized in that, After detecting the first open-circuit voltage of the battery under test, the method further includes: If the first open-circuit voltage is normal, increase the hydrogen pressure at the anode; Detect the second open-circuit voltage of the battery under test; If the second open-circuit voltage is abnormal, it is determined that the battery under test has the membrane electrode perforation problem; or, if the second open-circuit voltage is normal, it is determined that the battery under test does not have the membrane electrode perforation problem.

8. The method for troubleshooting low battery voltage according to claim 1, characterized in that, The troubleshooting of open and short circuits includes checking the inspection pointer, checking the bipolar plate edge curling, and checking for foreign objects mixed in with the fuel cell stack.

9. The method for troubleshooting low battery voltage according to claim 1, characterized in that, When a single low voltage phenomenon occurs in the fuel cell under test, after performing open-circuit and short-circuit troubleshooting on the fuel cell under test, the method further includes: If the open circuit and short circuit investigation indicates that the fuel cell under test has open circuit and short circuit problems, rectify the open circuit and short circuit problems of the fuel cell under test.

10. The method for troubleshooting low battery voltage according to claim 1, characterized in that, After performing membrane electrode perforation inspection on the battery under test when the open circuit and short circuit troubleshooting indicates that the battery under test does not have open circuit or short circuit problems, the procedure further includes: If the membrane electrode perforation investigation indicates that the fuel cell stack under test has a membrane electrode perforation problem, replace the membrane electrode of the fuel cell stack under test.

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