Method for predicting the lifetime of a membrane electrode assembly of a fuel cell for power generation

Abstract

A method for predicting the lifetime of a membrane electrode assembly (MEA) of a fuel cell for power generation, comprising: deriving operating conditions for accelerated degradation applicable to the fuel cell; operating the fuel cell for a specific time under the derived operating conditions for accelerated degradation and under normal operating conditions, and identifying the degree of degradation of the fuel cell under each operating condition; calculating an acceleration factor based on the degrees of degradation identified under the operating conditions for accelerated degradation and under normal operating conditions; and predicting the lifetime of the membrane electrode assembly based on the acceleration factor.

Description

Technical Field

[0001] The present invention relates to a method for predicting the life of a membrane electrode assembly (MEA) of a fuel cell for power generation, and more particularly, to a method for predicting the life of a membrane electrode assembly of a fuel cell for power generation under operating conditions of accelerated degradation applicable to a fuel cell. Background Art

[0002] Generally, a fuel cell is a device that generates electric power by reacting hydrogen (H2) and oxygen (O2) with each other. A fuel cell includes a membrane electrode assembly (MEA). The membrane electrode assembly is configured to include an electrolyte membrane to which hydrogen ions (H+) are transferred, an anode configured to be stacked on one side of the electrolyte membrane to provide fuel (i.e., hydrogen (H2)), and a cathode configured to be stacked on the other side of the electrolyte to provide air (oxygen). A fuel cell stack is produced by sequentially stacking the membrane electrode assembly and separator plates on top of each other.

[0003] The biggest problems to be overcome in commercializing a polymer electrolyte membrane fuel cell (PEMFC) configured to have such a stack are its high price and short life.

[0004] To this end, evaluating the durability of a polymer electrolyte membrane is essential for its lifetime operation. In particular, it is very important to evaluate the durability of newly developed electrolyte membranes and to test whether a large number of purchased electrolyte membranes have durability.

[0005] On the other hand, much progress has been made in research on accelerated degradation operations for evaluating the durability of vehicle fuel cells, but research on accelerated degradation operations for evaluating the durability of fuel cells for power generation has not been conducted yet. Verification of the expected life (durability) etc. of the membrane electrode assembly of a fuel cell requires a considerable amount of time and effort. Therefore, there is a need to develop a technology applicable to a fuel cell that can estimate the expected life of a membrane electrode assembly based on operating conditions of accelerated degradation.

[0006] The above information disclosed in this background art section is only for enhancing the understanding of the background art of the present disclosure, and should not be regarded as an admission that the information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0007] An object of the present invention is to provide a method for deriving operating conditions of accelerated degradation applicable to a fuel cell for power generation, and a method for predicting the life of a membrane electrode assembly of a fuel cell using the derived operating conditions of accelerated degradation.

[0008] According to one aspect of the present disclosure, a method for predicting the life of a membrane electrode assembly of a fuel cell for power generation includes: deriving operating conditions for accelerated degradation applicable to the fuel cell; operating the fuel cell for a specific time under the derived operating conditions for accelerated degradation and under normal operating conditions, and then identifying the degree of degradation of the fuel cell and the trend of the degree of degradation under each operating condition; calculating an acceleration multiple based on the degrees of degradation identified under the operating conditions for accelerated degradation and under normal operating conditions; and predicting the life of the membrane electrode assembly based on the acceleration multiple.

[0009] In this method, deriving the operating conditions for accelerated degradation may include: applying a specific current to the fuel cell, but repeating the operation of the fuel cell at specific time intervals while changing the relative humidity conditions of the anode and cathode of the fuel cell and the temperature conditions of the fuel cell, and identifying the degree of degradation and the trend of the degree of degradation under each condition; checking whether the identified degree of degradation under each condition falls within a predetermined range of the degree of degradation, and comparing the trend of the identified degree of degradation with the trend of the degree of degradation identified after operating the fuel cell under normal operating conditions; and selecting such conditions: under which the identified degree of degradation falls within the predetermined range of the degree of degradation and the trend of the degree of degradation is the same as the trend of the degree of degradation identified under normal operating conditions.

[0010] In this method, the degree of degradation and the trend of the degree of degradation may indicate which one of the components of the fuel cell including the catalyst, the membrane, and the gas diffusion layer (GDL) is degraded most severely.

[0011] In this method, when operating the fuel cell for a specific time under the derived operating conditions for accelerated degradation and under normal operating conditions, and then identifying the degree of degradation of the fuel cell and the trend of the degree of degradation under each operating condition, the degree of degradation and the trend of the degree of degradation are identified based on at least one of open circuit voltage (OCV) analysis, voltage density analysis, current density analysis, ohmic analysis, crossover analysis, and electrochemically active surface area (ECSA) analysis.

[0012] In this method, calculating the acceleration multiple based on the degrees of degradation identified under the operating conditions for accelerated degradation and under normal operating conditions may include: calculating the accelerated degradation rate under the operating conditions for accelerated degradation based on the degree of degradation identified under the operating conditions for accelerated degradation; calculating the normal degradation rate under normal operating conditions based on the degree of degradation identified under normal operating conditions; and calculating the acceleration multiple by dividing the accelerated degradation rate by the normal degradation rate.

[0013] In this method, the accelerated degradation rate and the normal degradation rate can indicate the slope of a curve graph, which is obtained by matching voltage values based on time with the same current density as a reference after operating the fuel cell over time under normal operating conditions and under operating conditions of accelerated degradation.

[0014] In this method, the acceleration multiple can indicate the multiple of fuel cell degradation when operating under operating conditions of accelerated degradation compared to when operating under normal operating conditions.

[0015] In this method, predicting the life of the membrane electrode assembly based on the acceleration multiple can include: deriving the time it takes for the performance of the fuel cell to decrease by a predetermined percentage from the initial performance when operating the fuel cell under operating conditions of accelerated degradation; and predicting the life of the membrane electrode assembly by multiplying the derived time by the acceleration multiple.

[0016] This method may further include: based on the derived operating conditions of accelerated degradation applicable to the fuel cell, deriving the optimal current conditions to be applied to the fuel cell so that the fuel cell has optimal durability.

[0017] In this method, deriving the optimal current conditions to be applied to the fuel cell may include: among the derived operating conditions of accelerated degradation, fixing the relative humidity conditions of the anode and cathode of the fuel cell and the temperature conditions of the fuel cell, operating the fuel cell by applying a plurality of different currents to the fuel cell, and identifying the degree of degradation of the fuel cell under the conditions of each of the plurality of currents, and selecting the current condition with the lowest degree of degradation of the fuel cell as the optimal current condition.

[0018] According to the present disclosure, operating conditions of the degree of accelerated degradation applicable to the fuel cell can be derived, and the life of the membrane electrode assembly of the fuel cell can be easily predicted using the derived operating conditions of accelerated degradation. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In conjunction with the accompanying drawings, the above and other objects, features, and other advantages of the present disclosure will be more clearly understood from the following detailed description, wherein:

[0020] Figure 1 is a diagram showing a flow of a method for performing prediction of the life of a membrane electrode assembly of a fuel cell for power generation according to an exemplary embodiment of the present disclosure;

[0021] Figure 2 is a flowchart showing steps of deriving operating conditions of accelerated degradation applicable to a fuel cell for power generation in a method for predicting the life of a membrane electrode assembly of a fuel cell for power generation according to an exemplary embodiment of the present disclosure;

[0022] Figure 3It is a table of operating conditions for deriving operating conditions for accelerated degradation applicable to a fuel cell for power generation in a method for predicting the life of a membrane electrode assembly of a fuel cell for power generation according to an exemplary embodiment of the present disclosure;

[0023] Figure 4 It is a graph showing Figure 3 the analysis results of the degree of degradation under each condition in;

[0024] Figure 5 It is a graph showing the durability obtained by operating over time under normal operating conditions and the durability obtained by operating over time under accelerated degradation operating conditions in a method for predicting the life of a membrane electrode assembly of a fuel cell for power generation according to an exemplary embodiment of the present disclosure;

[0025] Figure 6 It is a graph showing the accelerated degradation rate under accelerated operating conditions and the degradation rate under normal operating conditions in a method for predicting the life of a membrane electrode assembly of a fuel cell for power generation according to an exemplary embodiment of the present disclosure;

[0026] Figure 7 It is a graph showing the steps of calculating the acceleration factor in a method for predicting the life of a membrane electrode assembly of a fuel cell for power generation according to an exemplary embodiment of the present disclosure;

[0027] Figure 8 It is a graph showing the steps of predicting the life of the membrane electrode assembly based on the acceleration factor in a method for predicting the life of a membrane electrode assembly of a fuel cell for power generation according to an exemplary embodiment of the present disclosure; and

[0028] Figure 9 It is a graph showing the steps of determining the effectiveness of the derived operating conditions for accelerated degradation in a method for predicting the life of a membrane electrode assembly of a fuel cell for power generation according to an exemplary embodiment of the present disclosure. Detailed Description of the Invention

[0029] Hereinafter, a method for predicting the life of a membrane electrode assembly of a fuel cell for power generation according to an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

[0030] Figure 1 It is a graph showing the flow of a method for performing a method for predicting the life of a membrane electrode assembly of a fuel cell for power generation according to an exemplary embodiment of the present disclosure. Figure 2 It is a flowchart showing the steps of deriving operating conditions for accelerated degradation applicable to a fuel cell for power generation. Figure 3 It is a table of operating conditions for deriving operating conditions for accelerated degradation applicable to a fuel cell for power generation. Figure 4 It is a graph showing Figure 3 the analysis results of the degree of degradation under each condition in;Figure 5 is a graph showing the durability obtained by running over time under normal operating conditions and the durability obtained by running over time under accelerated degradation operating conditions. Figure 6 is a graph showing the accelerated degradation rate under accelerated operating conditions and the degradation rate under normal operating conditions. Figure 7 is a graph showing the steps of calculating the acceleration multiple. Figure 8 is a graph showing the steps of predicting the life of a membrane electrode assembly based on the acceleration multiple. Figure 9 is a graph showing the steps of determining the validity of the derived operating conditions for accelerated degradation.

[0031] As Figure 1 shown, a method for predicting the life of a membrane electrode assembly of a fuel cell for power generation according to an exemplary embodiment of the present disclosure includes: step S100 of deriving operating conditions for accelerated degradation applicable to the fuel cell; step S200 of operating the fuel cell for a specific time under the derived operating conditions for accelerated degradation and under normal operating conditions, and then identifying the degree of degradation of the fuel cell under each operating condition; step S300 of calculating an acceleration multiple based on the degrees of degradation identified under the derived operating conditions for accelerated degradation and under normal operating conditions; and step S400 of predicting the life of the membrane electrode assembly based on the calculated acceleration multiple.

[0032] Specifically, as Figure 2 shown, step S100 of deriving operating conditions for accelerated degradation applicable to the fuel cell includes: step S110 of applying a specific current to the fuel cell while changing the relative humidity conditions of the anode and cathode of the fuel cell and the temperature conditions of the fuel cell, repeating the operation of the fuel cell at specific time intervals, and then identifying the degree of degradation and the trend of the degree of degradation under each condition; step S120 of checking whether the identified degree of degradation under each condition falls within a predetermined range of the degree of degradation and comparing the trend of the degree of degradation with the trend of the degree of degradation identified after operating the fuel cell under normal operating conditions; and step S130 of selecting, from the identified degrees of degradation, such conditions that the degree of degradation falls within the predetermined range of the degree of degradation and the trend of the degree of degradation is the same as the trend of the degree of degradation identified under normal operating conditions.

[0033] More specifically, according to the exemplary embodiment, in the step of applying a specific current to the fuel cell while changing the relative humidity conditions of the anode and cathode of the fuel cell and the temperature conditions of the fuel cell, repeating the operation of the fuel cell at specific time intervals, and then identifying the degree of degradation and the trend of the degree of degradation under each condition, as Figure 3 shown, the fuel cell is repeatedly operated at specific time intervals under six different conditions, and then at Figure 4Identify the degree of deterioration and the trend of the degree of deterioration under each condition.

[0034] Refer to the following Figure 3 and Figure 4 Describe the steps to identify the degree of deterioration and the trend of the degree of deterioration under each condition (Condition 1 to Condition 6).

[0035] 1. Condition 1

[0036] 1-1. With the fuel cell stack rotated 90 degrees, at a relative humidity of 50%, supply hydrogen and oxygen to the anode and cathode respectively, apply a current of X A / cm 2 to the fuel cell, and operate the fuel cell for 60 minutes.

[0037] 1-2. After 60 minutes, stop applying current to the fuel cell, thus entering the open circuit voltage (OCV) state. In this state, at a relative humidity of 50%, supply hydrogen and oxygen to the anode and cathode respectively, and operate the fuel cell for 60 minutes.

[0038] 1-3. Repeatedly perform operations 1-1 and 1-2, and identify the degree of deterioration and the trend of the degree of deterioration at 100-hour intervals through performance analysis.

[0039] 2. Condition 2

[0040] 2-1. With the fuel cell stack rotated 90 degrees, at a relative humidity of 50%, supply hydrogen and oxygen to the anode and cathode respectively, apply a current of X A / cm 2 to the fuel cell, and operate the fuel cell for 60 minutes.

[0041] 2-2. After 60 minutes, stop applying current to the fuel cell, thus entering the open circuit voltage (OCV) state. In this state, at a relative humidity of 0%, supply hydrogen and oxygen to the anode and cathode respectively, and operate the fuel cell for 60 minutes.

[0042] 2-3. Repeatedly perform operations 2-1 and 2-2, and identify the degree of deterioration and the trend of the degree of deterioration at 100-hour intervals through performance analysis.

[0043] 3. Condition 3

[0044] 3-1. With the fuel cell stack rotated 75 degrees, at a relative humidity of 50%, supply hydrogen and oxygen to the anode and cathode respectively, apply a current of X A / cm 2 to the fuel cell, and operate the fuel cell for 60 minutes.

[0045] After 3 - 2.60 minutes, the current applied to the fuel cell is stopped, thus entering the open - circuit voltage (OCV) state. In this state, at 0% relative humidity, hydrogen and oxygen are supplied to the anode and cathode respectively, and the fuel cell is operated for 60 minutes.

[0046] 3 - 3. Operations 3 - 1 and 3 - 2 are repeatedly executed, and the degree of degradation and the trend of the degree of degradation are identified at 100 - hour intervals through performance analysis.

[0047] 4. Condition 4

[0048] 4 - 1. In a state where the fuel cell stack has risen by 60 degrees, at 50% relative humidity, hydrogen and oxygen are supplied to the anode and cathode respectively, and a current of X A / cm 2 is applied to the fuel cell, and the fuel cell is operated for 60 minutes.

[0049] 4 - 2. After 60 minutes, the current applied to the fuel cell is stopped, thus entering the open - circuit voltage (OCV) state. In this state, under the condition of 0% relative humidity, hydrogen and oxygen are supplied to the anode and cathode respectively, and the fuel cell is operated for 60 minutes.

[0050] 4 - 3. Operations 4 - 1 and 4 - 2 are repeatedly executed, and the degree of degradation and the trend of the degree of degradation are identified at 100 - hour intervals through performance analysis.

[0051] 5. Condition 5

[0052] 5 - 1. In a state where the fuel cell stack has risen by 60 degrees, at 50% relative humidity, hydrogen and oxygen are supplied to the anode and cathode respectively, and a current of X A / cm 2 is applied to the fuel cell, and the fuel cell is operated for 5 minutes.

[0053] 5 - 2. After 5 minutes, the current applied to the fuel cell is stopped, thus entering the open - circuit voltage (OCV) state. In this state, at 0% relative humidity, hydrogen and oxygen are supplied to the anode and cathode respectively, and the fuel cell is operated for 5 minutes.

[0054] 5 - 3. Operations 5 - 1 and 5 - 2 are repeatedly executed, and the degree of degradation and the trend of the degree of degradation are identified at 100 - hour intervals through performance analysis.

[0055] 6. Condition 6

[0056] 6 - 1. In a state where the fuel cell stack has risen by 60 degrees, at 100% relative humidity, hydrogen and oxygen are supplied to the anode and cathode respectively, and a current of X A / cm 2 is applied to the fuel cell, and the fuel cell is operated for 60 minutes.

[0057] After 6 - 2.60 minutes, the current applied to the fuel cell is stopped, thus entering the open - circuit voltage (OCV) state. In this state, at 0% relative humidity, hydrogen and oxygen are supplied to the anode and cathode respectively, and the fuel cell is operated for 5 minutes.

[0058] 6 - 3. Operations 6 - 1 and 6 - 2 are repeatedly performed, and the degree of degradation and the trend of the degree of degradation are identified at 100 - hour intervals through performance analysis.

[0059] Under Conditions 1 to 6, the value of X in the current of X A / cm 2 applied to the fuel cell is in the range of 0 to 1.5.

[0060] Under Conditions 1 to 6, the fuel cell is operated, and then as Figure 4 shown, the degree of degradation and the trend of the degree of degradation under each condition can be identified. At this point, the degree of degradation and the trend of the degree of degradation indicate which of the components such as the catalyst, membrane, and gas diffusion layer (GDL) included in the fuel cell are degraded more.

[0061] In addition, as Figure 4 shown, the degree of degradation and the trend of the degree of degradation can be identified based on at least one or more of open - circuit voltage (OCV) analysis, voltage - density analysis, current - density analysis, ohmic analysis, permeation analysis, and electrochemical surface area (ECSA) analysis. OCV analysis identifies how much the membrane is damaged. Voltage - density analysis and current - density analysis identify how much the performance of all fuel cell stacks is reduced. Ohmic analysis identifies how much the resistance of the fuel cell stack has increased. Permeation analysis identifies how much hydrogen the membrane allows to pass through. ECSA analysis identifies how much the active area of the catalyst has decreased. The degree of degradation of the fuel cell is determined by the results of each of these analyses.

[0062] According to the present disclosure, the degree of degradation and the trend of the degree of degradation under Conditions 1 to 6 are identified as described above. Subsequently, it is checked whether the identified degree of degradation under each condition falls within a predetermined range of the degree of degradation, and the trend of the degree of degradation is compared with the trend of the degree of degradation identified after operating the fuel cell under normal operating conditions. Subsequently, such conditions are selected from Conditions 1 to 6 as the operating conditions for accelerated degradation applicable to the fuel cell: under this condition, the identified degree of degradation falls within the predetermined range of the degree of degradation and the trend of the degree of degradation is the same as the trend of the degree of degradation identified under normal operating conditions.

[0063] According to an exemplary embodiment, a predetermined range of the degree of degradation is a range of the degree of degradation in which the performance of the fuel cell stack has decreased by 5% to 20% of its initial performance based on the voltage of the fuel cell stack. In this regard, the time point at which the performance has decreased by 20% of the initial performance based on the voltage of the fuel cell stack is the time point at which the operation of the relevant fuel cell system must be terminated. In addition, the time point at which the performance has decreased by 5% of the initial performance based on the voltage of the fuel cell stack is the initial time point at which the degree of degradation of the constituent elements within the relevant fuel cell stack can be identified.

[0064] In other words, identify under which of Conditions 1 to 6 the performance has decreased by 5% to 20% of the initial performance based on the voltage of the fuel cell stack; and identify under which conditions the trend of the degree of degradation is consistent with the trend of the degree of degradation identified after operating the fuel cell under normal operating conditions. Therefore, the obtained conditions are selected as the operating conditions for the accelerated degradation of the fuel cell.

[0065] On the other hand, in step S200 of operating the fuel cell for a specific time under the derived operating conditions for accelerated degradation and under normal operating conditions and then identifying the degree of degradation of the fuel cell under each operating condition, the fuel cell can be operated for a specific time under the operating conditions for accelerated degradation derived in step S100 and under normal operating conditions, and then as Figure 5 shown, the degree of degradation of the fuel cell under each operating condition and the trend of its degree of degradation can be identified. Specifically, Figure 5 is a graph showing the voltage of the fuel cell stack under each operating condition with respect to the current density generated by operating the fuel cell for a specific time under the operating conditions for accelerated degradation and under normal operating conditions. Referring to Figure 5 , the rate of performance decrease under each operating condition, that is, the degree of degradation and the trend of the degree of degradation, can be identified through the rate of decrease of the voltage of the fuel cell stack.

[0066] In addition, step S300 of calculating the acceleration multiple based on the degree of degradation identified under the operating conditions for accelerated degradation and under normal operating conditions in step S200 may include: step S310 of calculating the accelerated degradation rate under the operating conditions for accelerated degradation based on the degree of degradation identified under the operating conditions for accelerated degradation; step S320 of calculating the normal degradation rate under normal operating conditions based on the derived degree of degradation under normal operating conditions; and step S330 of calculating the acceleration multiple by dividing the accelerated degradation rate by the normal degradation rate.

[0067] More specifically, in order to calculate the accelerated degradation rate and the normal degradation rate, by using the same current density as a reference, the Figure 5 voltage values on the graph are matched based on time to obtainFigure 6 the curve graph in Figure 6 , the slope of curve graph A indicates the normal degradation rate, and the slope of curve graph B indicates the accelerated degradation rate.

[0068] Using the above method, the accelerated degradation rate and the normal degradation rate are calculated, and then the acceleration multiple is calculated by dividing the accelerated degradation rate by the normal degradation rate.

[0069] At this point, the acceleration multiple indicates the multiple of degradation when the fuel cell operates under accelerated degradation operating conditions compared to when it operates under normal operating conditions.

[0070] On the other hand, step S400 of predicting the life of the membrane electrode assembly based on the acceleration multiple may include: step S410 of deriving the time taken for the performance of the fuel cell to decrease by a predetermined percentage of its initial performance when the fuel cell operates under accelerated degradation operating conditions; and step S420 of predicting the life of the membrane electrode assembly by multiplying the derived time by the acceleration multiple.

[0071] According to an exemplary embodiment, when the acceleration multiple calculated in step S300 is 20 and the time taken for the performance of the membrane electrode assembly of the fuel cell to decrease by 20% of its initial performance is 1000 hours, in the case where the fuel cell operates under normal operating conditions, the expected life of the membrane electrode assembly of the fuel cell is 20000 hours, which is obtained by multiplying 1000 hours by 20. At this point, the time point when the fuel cell decreases by 20% of its initial performance refers to the time point when the operation of the fuel cell must end.

[0072] In this way, according to the present disclosure, the operating conditions of accelerated degradation applicable to the fuel cell can be derived, and the derived operating conditions of accelerated degradation can be used to easily predict the life of the membrane electrode assembly of the fuel cell.

[0073] On the other hand, the method for predicting the life of the membrane electrode assembly of the fuel cell according to an exemplary embodiment of the present disclosure may further include step S500: after the step of deriving the operating conditions of accelerated degradation applicable to the fuel cell, with reference to the derived operating conditions of accelerated degradation applicable to the fuel cell, deriving the optimal current conditions to be applied to the fuel cell so that the fuel cell has the best durability.

[0074] Specifically, the steps of deriving the optimal current conditions to be applied to the fuel cell may include: step S510, among the derived accelerated degradation operating conditions, fixing the relative humidity conditions of the anode and cathode of the fuel cell and the temperature conditions of the fuel cell, then applying a plurality of different currents to the fuel cell, operating the fuel cell, and identifying the degree of degradation of the fuel cell under the conditions of each of the plurality of currents; and step S520, selecting the current condition with the lowest degree of degradation of the fuel cell as the optimal current condition.

[0075] More specifically, according to an exemplary embodiment, among the derived accelerated degradation operating conditions, the relative humidity conditions of the anode and cathode of the fuel cell and the temperature conditions of the fuel cell are fixed. Subsequently, different currents are applied to the fuel cell, namely a current of 0.2 A / cm 2 of current, a current of 0.5 A / cm 2 of current, and a current of 1.0 A / cm 2 of current, operate the fuel cell, identify the degree of degradation of the fuel cell and the trend of the degree of degradation under the conditions of each current, and select the condition with the lowest degree of degradation as the optimal current condition.

[0076] According to an exemplary embodiment of the present disclosure, the above steps of the method for predicting the life of the MEA of a fuel cell for power generation may be performed by a processor (e.g., a computer, a microprocessor, a CPU, an ASIC, a circuit, a logic circuit, etc.) having an associated non-transitory memory storing software instructions for the processor.

Claims

1. A method for predicting the lifespan of a membrane electrode assembly of a fuel cell for power generation, the method comprising: Deriving operating conditions for accelerated degradation applicable to the fuel cell; Operating the fuel cell for a specific time under the derived operating conditions for accelerated degradation and under normal operating conditions, and then identifying the degree of degradation of the fuel cell and the trend of the degree of degradation under each operating condition; Calculating an acceleration multiple based on the degree of degradation identified under the derived operating conditions for accelerated degradation and under the normal operating conditions; And Predicting the lifespan of the membrane electrode assembly based on the acceleration multiple, wherein deriving the operating conditions for accelerated degradation includes: Applying a specific current to the fuel cell, but while changing the relative humidity conditions of the anode and cathode of the fuel cell and the temperature conditions of the fuel cell, repeating the operation of the fuel cell at specific time intervals, and identifying the degree of degradation and the trend of the degree of degradation under each of the relative humidity and temperature conditions, and Based on the identified degree of degradation and the trend of the degree of degradation, selecting from the relative humidity and temperature conditions such conditions that the identified degree of degradation falls within a predetermined range of the degree of degradation and the trend of the degree of degradation is the same as the trend of the degree of degradation identified under the normal operating conditions.

2. The method according to claim 1, wherein Deriving the operating conditions for accelerated degradation further includes: Checking whether the identified degree of degradation under each of the relative humidity and temperature conditions falls within a predetermined range of the degree of degradation, and comparing the trend of the identified degree of degradation with the trend of the degree of degradation identified after operating the fuel cell under the normal operating conditions.

3. The method according to claim 2, wherein The degree of degradation and the trend of the degree of degradation indicate which one of the components of the fuel cell including the catalyst, the membrane, and the gas diffusion layer degrades most severely.

4. The method according to claim 1, wherein, When operating the fuel cell for a specific time under the derived operating conditions for accelerated degradation and under the normal operating conditions, and then identifying the degree of degradation of the fuel cell and the trend of the degree of degradation under each operating condition, the degree of degradation and the trend of the degree of degradation are identified based on at least one of open circuit voltage analysis, voltage density analysis, current density analysis, ohmic analysis, permeation analysis, and electrochemically active surface area analysis.

5. The method according to claim 1, wherein, Calculating the acceleration multiple based on the degree of degradation identified under the derived operating conditions for accelerated degradation and under the normal operating conditions includes: Calculating the accelerated degradation rate under the derived operating conditions for accelerated degradation based on the degree of degradation identified under the derived operating conditions for accelerated degradation; Calculating the normal degradation rate under the normal operating conditions based on the degree of degradation identified under the normal operating conditions; and Calculating the acceleration multiple by dividing the accelerated degradation rate by the normal degradation rate.

6. The method according to claim 5, wherein, The slopes of the curves indicating the accelerated degradation rate and the normal degradation rate are obtained by matching voltage values based on time with the same current density as a reference after operating the fuel cell over time under the normal operating conditions and under the operating conditions of the derived accelerated degradation.

7. The method according to claim 1, wherein, The acceleration multiple indicates the multiple of degradation of the fuel cell when operating under the operating conditions of the derived accelerated degradation compared to when operating under the normal operating conditions.

8. The method according to claim 1, wherein Predicting the lifetime of the membrane electrode assembly based on the acceleration multiple includes: Deriving the time it takes for the performance of the fuel cell to decrease by a predetermined percentage from the initial performance when operating the fuel cell under the operating conditions of the derived accelerated degradation; and Predicting the lifetime of the membrane electrode assembly by multiplying the derived time by the acceleration multiple.

9. The method according to claim 1, further comprising: Based on the derived operating conditions of the accelerated degradation applicable to the fuel cell, deriving the optimal current conditions to be applied to the fuel cell such that the fuel cell has optimal durability.

10. The method according to claim 9, wherein, Deriving the optimal current conditions to be applied to the fuel cell includes: Among the derived operating conditions of the accelerated degradation, fixing the relative humidity conditions of the anode and cathode of the fuel cell and the temperature conditions of the fuel cell, operating the fuel cell by applying a plurality of different currents to the fuel cell, and identifying the degree of degradation of the fuel cell under the conditions of each of the plurality of different currents, and Selecting the current condition with the lowest degree of degradation of the fuel cell as the optimal current condition.

Images