PEM electrolytic cell electrochemical performance testing system and method

Abstract

The present application discloses a system and method for testing the electrochemical performance of a PEM electrolyzer. The system includes an upper end plate, a plurality of longitudinal copper bars, an insulating plate, a plurality of conductive plates, a cathode diffusion layer, an anode diffusion layer, and a blind end plate, which are arranged in sequence from top to bottom. The present application provides a plurality of cathode diffusion sheets in the cathode diffusion layer, and provides a plurality of conductive plates corresponding to the cathode diffusion sheets. The number of the cathode diffusion sheets and the conductive plates is the same, so as to realize the partition detection of the electrochemical performance corresponding to each cathode diffusion sheet, and determine whether there is a difference in the electrochemical performance of different areas in a single-section reaction zone.

Description

Technical Field

[0001] The present application relates to the technical field of production and processing of PEM water electrolyzers, and in particular to a system and method for testing the electrochemical performance of a PEM electrolyzer. Background Art

[0002] The ‌PEM electrolyzer‌ is a water electrolysis hydrogen production device that uses a proton exchange membrane (PEM) as a solid electrolyte. The core components of a PEM electrolyzer include a membrane electrode assembly (MEA), a bipolar plate (BPP), and a current collector. Usually, the reaction zone of each section of a PEM electrolyzer has a certain area. In order to improve the overall performance of the electrolyzer, it is necessary to know whether there are differences in the electrochemical performance of different areas within a single section of the reaction zone, so as to find out the weak points in performance for analysis and improvement. The common electrolyzer core is a monolithic structure, which can only detect the overall average electrochemical performance of a single section, and cannot accurately detect the electrochemical performance of different internal regions. Summary of the invention

[0003] The embodiments of the present application provide a system and method for testing the electrochemical performance of a PEM electrolyzer, which can solve the technical problem that the current electrolyzer core is an integral structure and can only detect the overall average electrochemical performance of a single section, but cannot accurately detect the electrochemical performance of different internal regions.

[0004] The embodiment of the present application provides a PEM electrolytic cell electrochemical performance testing system, comprising an upper end plate, a plurality of longitudinal copper bars, an insulating plate, a plurality of conductive plates, a cathode diffusion layer, an anode diffusion layer, and a blind end plate arranged in sequence from top to bottom;

[0005] The anode water interface and the cathode hydrogen interface are alternately arranged at the short sides of the surface of the upper end plate;

[0006] The insulating plate is provided with a water port corresponding to the anode water interface, and is provided with a hydrogen port corresponding to the cathode hydrogen interface;

[0007] The longitudinal copper bars are fixed on the upper surface of the insulating plate, the conductive plates are fixed on the lower surface of the insulating plate, the number of the conductive plates is the same as the longitudinal copper bars, and the longitudinal copper bars are connected to the conductive plates in a one-to-one correspondence;

[0008] The cathode diffusion layer is provided with a plurality of cathode diffusion sheets, the cathode diffusion sheets are arranged corresponding to the conductive plates, the number of the cathode diffusion sheets is the same as the number of the conductive plates, and the cathode diffusion sheets are connected to the conductive plates one by one;

[0009] The cathode diffusion layer is provided with a first anode water inlet corresponding to the water inlet, and is provided with a first cathode hydrogen inlet corresponding to the hydrogen inlet; the cathode diffusion sheet is in communication with the first anode water inlet;

[0010] A central reaction zone is provided in the middle of the anode diffusion layer, and the central reaction zone is arranged corresponding to the cathode diffusion sheet;

[0011] The anode diffusion layer is provided with a second anode water inlet corresponding to the first anode water inlet, and is provided with a second cathode hydrogen inlet corresponding to the first cathode hydrogen inlet; the central reaction zone is connected to the second anode water inlet;

[0012] An epitaxial positive copper busbar for wiring is mounted below the blind end plate.

[0013] Furthermore, the blind end plate is connected to the edge of the upper end plate via fasteners.

[0014] Furthermore, at least two positioning pins are provided on the upper surface of the blind end plate, and the at least two positioning pins are provided at the short sides of both sides of the blind end plate.

[0015] Furthermore, the anode water interface and the cathode hydrogen interface are circular, the water inlet and the hydrogen inlet are circular, and the first anode water inlet, the first cathode hydrogen inlet, the second anode water inlet, the second cathode hydrogen inlet, the cathode diffusion plate and the central reaction zone are rectangular or rounded rectangular.

[0016] Furthermore, the insulating plate is provided with an O-ring around the water inlet and the hydrogen inlet; the upper surface of the insulating plate is provided with a slot, and each of the longitudinal copper bars is fixed in the slot; the lower surface of the insulating plate is provided with a groove, and the conductive plate is fixed in the groove; the bottom of the slot is connected to the bottom of the groove, and the longitudinal copper bar passes through the bottom of the slot to be electrically connected to the conductive plate.

[0017] Furthermore, a membrane electrode proton membrane is provided on the lower surface of the cathode diffusion layer.

[0018] Furthermore, the first anode water inlet and the cathode diffusion sheet arranged adjacent thereto are connected via a first microchannel, and the adjacent cathode diffusion sheets are connected via a plurality of small groove structures. A first sealing ring is arranged around the first anode water inlet and the cathode diffusion sheet, and a second sealing ring is arranged around the first cathode hydrogen inlet.

[0019] Furthermore, a second microchannel is provided on the lower surface of the anode diffusion layer, and the central reaction zone is connected to the second anode water inlet through the second microchannel.

[0020] Furthermore, a third sealing ring is provided around the second anode water inlet, a fourth sealing ring is provided around the second cathode hydrogen inlet, and a fifth sealing ring is provided around the central reaction zone.

[0021] The present application provides a method for testing the electrochemical performance of a PEM electrolyzer, which is used in the PEM electrolyzer electrochemical performance testing system described above, and the method comprises:

[0022] Connect the PEM electrolytic cell electrochemical performance test system to the test equipment, wherein a sub-current sensor is connected in series between each longitudinal copper bar and the first node, the first node is connected to the negative electrode of the test equipment through a total current sensor, the epitaxial positive copper bar is connected to the second node, the second node is connected to the positive electrode of the test equipment, a sub-voltage sensor is provided between each longitudinal copper bar and the epitaxial positive copper bar, and a total voltage sensor is provided between the first node and the second node;

[0023] Starting the test equipment and the PEM electrolyzer electrochemical performance test system to collect data from the sub-current sensor, the total current sensor, the sub-voltage sensor, and the total voltage sensor;

[0024] Acquire a current density signal of a region corresponding to each cathode diffusion sheet to form a current density distribution diagram of a region corresponding to each cathode diffusion sheet;

[0025] Acquire a voltage signal of a region corresponding to each cathode diffusion sheet to form a polarization curve diagram of a region corresponding to each cathode diffusion sheet;

[0026] The overall current density signal and voltage signal of the PEM electrolyzer electrochemical performance test system are obtained to form an overall polarization curve diagram of the PEM electrolyzer electrochemical performance test system.

[0027] The electrochemical performance testing system and method for a PEM electrolyzer provided in the embodiments of the present application are characterized in that a cathode diffusion layer is provided with a plurality of cathode diffusion sheets, and a plurality of conductive plates are provided corresponding to the cathode diffusion sheets, and the number of the cathode diffusion sheets and the conductive plates are the same, thereby realizing partitioned detection of the electrochemical performance corresponding to each cathode diffusion sheet, and determining whether there are differences in the electrochemical performance of different areas within a single-section reaction zone. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0029] Figure 1 A schematic diagram of the decomposed structure of a PEM electrolyzer electrochemical performance testing system provided in an embodiment of the present application.

[0030] Figure 2 A bottom view of the insulation board provided in an embodiment of the present application.

[0031] Figure 3This is a schematic diagram of the structure of the PEM electrolyzer electrochemical performance testing system under test state provided in an embodiment of the present application.

[0032] Figure 4 A logic diagram of the electrochemical performance testing method for a PEM electrolyzer provided in an embodiment of the present application.

[0033] Figure 5 This is a current density distribution diagram obtained by the electrochemical performance testing method of the PEM electrolyzer provided in the embodiment of the present application.

[0034] Figure 6 Polarization curve diagram obtained by the electrochemical performance testing method of the PEM electrolyzer provided in the embodiment of the present application.

[0035] The markings in the figure are as follows:

[0036] Upper end plate 1, anode water interface 11, cathode hydrogen interface 12, longitudinal copper busbar 2, insulating plate 3, water inlet 31, hydrogen inlet 32, O-ring 33, card slot 34, groove 35, conductive plate 4, cathode diffusion layer 5, cathode diffusion sheet 51, first anode water inlet 52, first cathode hydrogen inlet 53, first microchannel 54, small groove structure 55, first sealing ring 56, second sealing ring 57, anode diffusion layer 6, central reaction zone 61, second anode water inlet 62, second cathode hydrogen inlet 63, third sealing ring 64, fourth sealing ring 65, fifth sealing ring 66, blind end plate 7, epitaxial positive copper busbar 71, positioning pin 72, fastener 8. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0038] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0039] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0040] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0041] For details, please refer to Figure 1 The present application embodiment provides a PEM electrolytic cell electrochemical performance testing system, the PEM electrolytic cell electrochemical performance testing system comprising an upper end plate 1, a plurality of longitudinal copper bars 2, an insulating plate 3, a plurality of conductive plates 4, a cathode diffusion layer 5, an anode diffusion layer 6, and a blind end plate 7 arranged in sequence from top to bottom;

[0042] The anode water interface 11 and the cathode hydrogen interface 12 are alternately arranged at the short sides of the surface of the upper end plate 1;

[0043] The insulating plate 3 is provided with a water inlet 31 corresponding to the anode water interface 11, and is provided with a hydrogen inlet 32 ​​corresponding to the cathode hydrogen interface 12;

[0044] The longitudinal copper bars 2 are fixed on the upper surface of the insulating plate 3, and the conductive plates 4 are fixed on the lower surface of the insulating plate 3. The number of the conductive plates 4 and the longitudinal copper bars 2 is the same, and the longitudinal copper bars 2 are connected to the conductive plates 4 in a one-to-one correspondence;

[0045] The cathode diffusion layer 5 is provided with a plurality of cathode diffusion sheets 51, and the cathode diffusion sheets 51 are arranged corresponding to the conductive plates 4, the number of the cathode diffusion sheets 51 and the number of the conductive plates 4 are the same, and the cathode diffusion sheets 51 are connected to the conductive plates 4 in a one-to-one correspondence;

[0046] The cathode diffusion layer 5 is provided with a first anode water inlet 52 corresponding to the water inlet 31, and is provided with a first cathode hydrogen inlet 53 corresponding to the hydrogen inlet 32; the cathode diffusion sheet 51 is in communication with the first anode water inlet 52;

[0047] A central reaction zone 61 is provided in the middle of the anode diffusion layer 6, and the central reaction zone 61 is provided corresponding to the cathode diffusion sheet 51;

[0048] The anode diffusion layer 6 is provided with a second anode water inlet 62 corresponding to the first anode water inlet 52, and is provided with a second cathode hydrogen inlet 63 corresponding to the first cathode hydrogen inlet 53; the central reaction zone 61 is connected to the second anode water inlet 62;

[0049] An epitaxial positive copper bus 71 for wiring is installed below the blind end plate 7 .

[0050] Furthermore, the blind end plate 7 is connected to the edge of the upper end plate 1 by a fastener 8. The fastener 8 is preferably a bolt, and bolts are installed on the outer edge of a circle, which ensures the water inlet and outlet interface and hydrogen collection interface of the device with the outside, and has good structural reliability.

[0051] The single longitudinal copper busbar 2 is used as the connection of the whole test device. It can be compatible with both the partition test and the whole test, and is flexible to adjust. The epitaxial positive copper busbar 71 facilitates the connection of the external test circuit.

[0052] Furthermore, at least two positioning pins 72 are provided on the upper surface of the blind end plate 7, and the at least two positioning pins 72 are provided at the short sides of both sides of the blind end plate 7. The positioning pins 72 improve the assembly efficiency and ensure that there is no misalignment between the components.

[0053] Furthermore, the anode water interface 11 and the cathode hydrogen interface 12 are circular, the water inlet 31 and the hydrogen inlet 32 ​​are circular, and the first anode water inlet 52, the first cathode hydrogen inlet 53, the second anode water inlet 62, the second cathode hydrogen inlet 63, the cathode diffusion plate 51 and the central reaction zone 61 are rectangular or rounded rectangular.

[0054] Furthermore, the insulating plate 3 is provided with an O-ring 33 around the water inlet 31 and the hydrogen inlet 32 ​​, thereby ensuring the sealing performance of the interface above the insulating plate 3 and having good self-strength.

[0055] See also Figure 2 A slot 34 is provided on the upper surface of the insulating plate 3, and each of the longitudinal copper bars 2 is fixed in the slot 34; a groove 35 is provided on the lower surface of the insulating plate 3, and the conductive plate 4 is fixed in the groove 35; the bottom of the slot 34 is connected to the bottom of the groove 35, and the longitudinal copper bars 2 pass through the bottom of the slot 34 to be electrically connected to the conductive plate 4.

[0056] The groove 35 is provided with an O-ring sealing structure to ensure the insulation between the conductive plates 4 and the good sealing performance below. The front of the conductive plate 4 is designed with a threaded blind hole. The back of the conductive plate 4 is in contact with the cathode diffusion layer 5 to ensure that the contact resistance is small enough, and the threaded interface on the front of the conductive plate 4 and the longitudinal copper bus 2 are tightly connected and the structure is reliable.

[0057] Furthermore, a membrane electrode proton membrane is provided on the lower surface of the cathode diffusion layer 5. The cathode diffusion layer 5 has two structures, one integrated and one separated, and has two corresponding frames on the outside. The two frame structures of the cathode diffusion layer 5 are compatible at the same time, meeting the test function and reducing the production cost.

[0058] Furthermore, the first anode water inlet 52 and the cathode diffusion sheet 51 disposed adjacent thereto are communicated with each other through a first microchannel 54, and the adjacent cathode diffusion sheets 51 are communicated with each other through a plurality of small groove structures 55. A first sealing ring 56 is disposed around the first anode water inlet 52 and the cathode diffusion sheet 51, and a second sealing ring 57 is disposed around the first cathode hydrogen inlet 53. The cathode diffusion layer 5 is a PTFE gasket, and the first sealing ring 56 and the second sealing ring 57 are convex ridge structures and soft material contact sealing structures, which can ensure good performance inside the slot core under a certain sealing pressure.

[0059] There is no microchannel at the first cathode hydrogen port 53, which ensures that there is a channel for generating hydrogen in the upper layer of the single-layer slot core structure.

[0060] Adjacent cathode diffusion sheets 51 are separated by a frame of a certain width, so as to realize insulation between cathode diffusion layers 5 in different regions. Meanwhile, the small groove structure 55 ensures that hydrogen can flow through both sides at the separation point.

[0061] Furthermore, a second microchannel is provided on the lower surface of the anode diffusion layer 6, and the central reaction zone 61 is connected to the second anode water inlet 62 through the second microchannel. The anode frame outside the anode diffusion layer 6 has only one structure, and the central reaction zone is not allowed to have partitions. The anode reaction zone is a whole to avoid excessive water flow resistance. The second microchannel ensures the inlet and outlet channels of the lower layer of the single-layer slot core structure.

[0062] Furthermore, a third sealing ring 64 is provided around the second anode water inlet 62 , a fourth sealing ring 65 is provided around the second cathode hydrogen inlet 63 , and a fifth sealing ring 66 is provided around the central reaction zone 61 .

[0063] The present application provides a method for testing the electrochemical performance of a PEM electrolyzer, which is used in the PEM electrolyzer electrochemical performance testing system described above, and the method comprises:

[0064] The PEM electrolytic cell electrochemical performance test system is connected to the test equipment, wherein a sub-current sensor is connected in series between each longitudinal copper bar 2 and the first node, the first node is connected to the negative electrode of the test equipment through a total current sensor, the epitaxial positive copper bar 71 is connected to the second node, the second node is connected to the positive electrode of the test equipment, a sub-voltage sensor is provided between each longitudinal copper bar 2 and the epitaxial positive copper bar 71, and a total voltage sensor is provided between the first node and the second node;

[0065] Starting the test equipment and the PEM electrolyzer electrochemical performance test system to collect data from the sub-current sensor, the total current sensor, the sub-voltage sensor, and the total voltage sensor;

[0066] Acquire a current density signal of a region corresponding to each cathode diffusion sheet 51 to form a current density distribution diagram of a region corresponding to each cathode diffusion sheet 51;

[0067] Acquire a voltage signal of a region corresponding to each cathode diffusion sheet 51 to form a polarization curve diagram of a region corresponding to each cathode diffusion sheet 51;

[0068] The overall current density signal and voltage signal of the PEM electrolyzer electrochemical performance test system are obtained to form an overall polarization curve diagram of the PEM electrolyzer electrochemical performance test system.

[0069] exist Figure 3In the figure, the sub-current sensors are I1, I2, I3, I4, I5, and I6, the total current sensor is I, the sub-voltage sensors are V1, V2, V3, V4, V5, and V6, and the total voltage sensor is V.

[0070] The conductive plate 4 is preferably made of TA2 to ensure long-term corrosion resistance, and the entire plate is made of platinum-plated conductive coating. The cathode and anode frames are preferably made of PSU material to ensure insulation and corrosion resistance. The height of the sealing ring on the frame is preferably 0.05~0.1mm, and three sealing rings with a width of 1.2mm are arranged on the front and back of the cathode frame. The anode frame is only arranged with a convex ridge sealing ring on the lower surface. The total height of these sealing rings must be guaranteed to be within a tolerance of ±0.02mm to ensure a good sealing effect, and at the same time ensure that the water inlet and outlet channels and the hydrogen generation channel are not intertwined or leaked.

[0071] in, Figure 5 is the current density distribution diagram, Figure 6 Based on the obtained current density and polarization curve, the relationship between the overall electrochemical performance of the electrolytic cell and the performance of different regions can be analyzed, and then the influence of changing a certain part design parameter on the electrolytic cell performance can be verified, thereby optimizing the structural design details of the electrolytic cell parts.

[0072] according to Figure 3 The schematic diagram is shown in the wiring diagram. Input a constant current to see the voltage values ​​of the six parts. Compare the differences in these voltages. The higher the voltage value, the worse the performance of this department. Then change the structure or size parameters of a certain part to improve the lowest electrochemical performance and ensure that the performance differences of the six parts of the single layer are small.

[0073] The electrochemical performance testing system and method for a PEM electrolyzer provided in the embodiment of the present application is characterized in that a cathode diffusion layer 5 is provided with a plurality of cathode diffusion sheets 51, and a plurality of conductive plates 4 are provided corresponding to the cathode diffusion sheets 51. The number of the cathode diffusion sheets 51 and the conductive plates 4 are the same, so that the electrochemical performance corresponding to each cathode diffusion sheet 51 can be detected in a partitioned manner, and whether there is a difference in the electrochemical performance of different areas within a single-section reaction zone can be determined.

[0074] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0075] The above is a detailed introduction to a PEM electrolyzer electrochemical performance testing system provided in an embodiment of the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solution and its core idea of ​​the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A PEM electrolyzer electrochemical performance testing system, characterized in that: It includes an upper end plate, a plurality of longitudinal copper bars, an insulating plate, a plurality of conductive plates, a cathode diffusion layer, an anode diffusion layer, and a blind end plate, which are arranged in sequence from top to bottom; a membrane electrode proton membrane is arranged on the lower surface of the cathode diffusion layer; The anode water interface and the cathode hydrogen interface are alternately arranged at the short sides of the surface of the upper end plate; The insulating plate is provided with a water port corresponding to the anode water interface, and is provided with a hydrogen port corresponding to the cathode hydrogen interface; The longitudinal copper bars are fixed on the upper surface of the insulating plate, the conductive plates are fixed on the lower surface of the insulating plate, the number of the conductive plates is the same as the longitudinal copper bars, and the longitudinal copper bars are connected to the conductive plates in a one-to-one correspondence; The cathode diffusion layer is provided with a plurality of cathode diffusion sheets, the cathode diffusion sheets are arranged corresponding to the conductive plates, the number of the cathode diffusion sheets is the same as the number of the conductive plates, and the cathode diffusion sheets are connected to the conductive plates one by one; The cathode diffusion layer is provided with a first anode water inlet corresponding to the water inlet, and is provided with a first cathode hydrogen inlet corresponding to the hydrogen inlet; the cathode diffusion sheet is in communication with the first anode water inlet; A central reaction zone is provided in the middle of the anode diffusion layer, and the central reaction zone is arranged corresponding to the cathode diffusion sheet; The anode diffusion layer is provided with a second anode water inlet corresponding to the first anode water inlet, and is provided with a second cathode hydrogen inlet corresponding to the first cathode hydrogen inlet; the central reaction zone is connected to the second anode water inlet; An epitaxial positive copper busbar for wiring is mounted below the blind end plate.

2. The PEM electrolyzer electrochemical performance testing system according to claim 1, characterized in that: The blind end plate is connected to the edge of the upper end plate by fasteners.

3. The PEM electrolyzer electrochemical performance testing system according to claim 1, characterized in that: At least two positioning pins are arranged on the upper surface of the blind end plate, and the at least two positioning pins are arranged at the short sides of both sides of the blind end plate.

4. The PEM electrolyzer electrochemical performance testing system according to claim 1, characterized in that: The anode water interface and the cathode hydrogen interface are circular, the water inlet and the hydrogen inlet are circular, and the first anode water inlet, the first cathode hydrogen inlet, the second anode water inlet, the second cathode hydrogen inlet, the cathode diffusion plate and the central reaction zone are rectangular or rounded rectangular.

5. The PEM electrolyzer electrochemical performance testing system according to claim 1, characterized in that: The insulating plate is provided with an O-ring around the water inlet and the hydrogen inlet; a card slot is provided on the upper surface of the insulating plate, and each of the longitudinal copper bars is fixed in the card slot; a groove is provided on the lower surface of the insulating plate, and the conductive plate is fixed in the groove; the bottom of the card slot is connected to the bottom of the groove, and the longitudinal copper bar passes through the bottom of the card slot and is electrically connected to the conductive plate.

6. The PEM electrolyzer electrochemical performance testing system according to claim 1, characterized in that: The first anode water inlet and the cathode diffusion sheet arranged adjacent thereto are connected via a first microchannel, and the adjacent cathode diffusion sheets are connected via a plurality of small groove structures. A first sealing ring is arranged around the first anode water inlet and the cathode diffusion sheet, and a second sealing ring is arranged around the first cathode hydrogen inlet.

7. The PEM electrolyzer electrochemical performance testing system according to claim 1, characterized in that: A second microchannel is provided on the lower surface of the anode diffusion layer, and the central reaction zone is communicated with the second anode water inlet through the second microchannel.

8. The PEM electrolyzer electrochemical performance testing system according to claim 1, characterized in that: A third sealing ring is arranged around the second anode water inlet, a fourth sealing ring is arranged around the second cathode hydrogen inlet, and a fifth sealing ring is arranged around the central reaction zone.

9. A method for testing the electrochemical performance of a PEM electrolyzer, characterized in that: The electrochemical performance testing system for a PEM electrolyzer according to any one of claims 1 to 8, the method comprising: Connect the PEM electrolytic cell electrochemical performance test system to the test equipment, wherein a sub-current sensor is connected in series between each longitudinal copper bar and the first node, the first node is connected to the negative electrode of the test equipment through a total current sensor, the epitaxial positive copper bar is connected to the second node, the second node is connected to the positive electrode of the test equipment, a sub-voltage sensor is provided between each longitudinal copper bar and the epitaxial positive copper bar, and a total voltage sensor is provided between the first node and the second node; Starting the test equipment and the PEM electrolyzer electrochemical performance test system to collect data from the sub-current sensor, the total current sensor, the sub-voltage sensor, and the total voltage sensor; Acquire a current density signal of a region corresponding to each cathode diffusion sheet to form a current density distribution diagram of a region corresponding to each cathode diffusion sheet; Acquire a voltage signal of a region corresponding to each cathode diffusion sheet to form a polarization curve diagram of a region corresponding to each cathode diffusion sheet; The overall current density signal and voltage signal of the PEM electrolyzer electrochemical performance test system are obtained to form an overall polarization curve diagram of the PEM electrolyzer electrochemical performance test system.

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