Preparation method of end collector plate for flow battery and resistance testing method of end collector plate

Abstract

The invention belongs to the technical field of flow batteries, and discloses a preparation method and a resistance testing method of an end collector plate for a flow battery, and the preparation method comprises the following steps: cleaning a metal plate and a bipolar plate; preparing a conductive adhesive; quickly and uniformly coating conductive adhesive on the lower end surface of the metal plate or the upper end surface of the bipolar plate; slowly adhering the upper end surface of the bipolar plate to the lower end surface of the metal plate to obtain a laminated plate structure; applying pressure to the upper and lower end faces of the laminated slab structure according to set pressure; and in the process of applying pressure to the laminated plate structure, the laminated plate structure is heated, and after the conductive adhesive is cured, the end collector plate is obtained. The resistance of the prepared end collector plate is far smaller than that of other end collector plates buried with copper nets, the internal resistance of a galvanic pile is effectively reduced, and the efficiency of the galvanic pile is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of liquid flow batteries, and in particular relates to a method for preparing an end current collecting plate for a liquid flow battery and a method for testing its resistance. Background Art

[0002] Liquid flow battery is an electrochemical energy storage technology and a new type of battery. Liquid flow battery consists of a battery stack unit, electrolyte, electrolyte storage and supply unit, and management control unit. It is a high-performance battery that separates the positive and negative electrolytes and circulates them separately. It has the characteristics of high capacity, wide application field (environment), and long cycle life. It is a new energy product.

[0003] The stack structure of a liquid flow battery usually includes several single cells connected in series, and end collecting plates are arranged at both ends of the stack to connect the single cells and collect the current. The outer side of the end collecting plate is successively provided with liquid inlet and outlet plates and end plates, and the inner side of the end collecting plate is provided with a battery frame plate. The end plate is used to compress the stack structure.

[0004] As one of the key components of a flow battery stack, the end current collector has the main functions of collecting and conducting current and supporting positive and negative electrodes. Therefore, the end current collector requires good mechanical strength, flatness, and a small resistance value. Summary of the invention

[0005] In view of the above problems, the present invention provides a method for preparing an end current collecting plate for a liquid flow battery and a resistance testing method thereof, which adopts the following technical solutions:

[0006] A method for preparing an end current collecting plate for a liquid flow battery comprises the following steps: cleaning a metal plate and a bipolar plate; preparing a conductive adhesive; quickly and evenly applying the conductive adhesive to the lower end surface of the metal plate or the upper end surface of the bipolar plate; slowly pasting the upper end surface of the bipolar plate to the lower end surface of the metal plate to obtain a laminated plate structure; applying pressure to the upper and lower end surfaces of the laminated plate structure according to a set pressure; in the process of applying pressure to the laminated plate structure, heating the laminated plate structure, and after the conductive adhesive is cured, obtaining the end current collecting plate.

[0007] Further, the set pressure is 20T-100T / m 2 .

[0008] Furthermore, the temperature for heating the laminated plate structure is determined according to the curing temperature of the conductive adhesive.

[0009] The present invention also provides an end current collecting plate for a liquid flow battery, which is prepared by the preparation method of the end current collecting plate for a liquid flow battery.

[0010] Furthermore, it includes stacked metal plates, conductive adhesive and bipolar plates, wherein the metal plates are copper plates.

[0011] Furthermore, the conductive adhesive includes conductive silver adhesive, conductive copper adhesive, epoxy metal adhesive, graphite conductive adhesive or graphite paste.

[0012] Furthermore, the thickness of the conductive adhesive is 10um-100um.

[0013] The present invention also provides a method for testing the resistance of the end current collecting plate for a liquid flow battery, comprising the following steps:

[0014] Laying a first carbon felt layer and a second carbon felt layer on the upper and lower end surfaces of the bipolar plate respectively, laying a first gold-plated electrode on the upper end of the first carbon felt layer, and laying a second gold-plated electrode on the lower end of the second carbon felt layer, to obtain a first sample assembly to be tested;

[0015] Applying pressure to the upper and lower ends of the first sample component to be tested, and measuring the resistance value of the first sample component to be tested under the set pressure;

[0016] Removing the bipolar plate in the middle of the first sample assembly to be tested to obtain a second sample assembly to be tested, and measuring the resistance value of the second sample assembly to be tested under a set pressure;

[0017] removing the first carbon felt layer or the second carbon felt layer in the second sample assembly to be tested to obtain a third sample assembly to be tested, measuring the resistance value of the third sample assembly to be tested under a set pressure to obtain the resistance value of the carbon felt layer;

[0018] Determine the contact resistance between the bipolar plate and the first carbon felt layer or the second carbon felt layer according to the resistance value of the first sample assembly to be tested, the resistance value of the carbon felt, the resistance value of the bipolar plate, and the contact area between the bipolar plate and the first carbon felt layer and the second carbon felt layer;

[0019] The first end plate, the first plate frame, the first end current collecting plate, the third carbon felt layer, the fourth carbon felt layer, the second end current collecting plate, the second plate frame and the second end plate are stacked in sequence, and the first end plate and the second end plate are fixedly connected by a plurality of components to obtain a fourth sample assembly to be tested;

[0020] Measuring the resistance value of the fourth sample component to be tested;

[0021] The resistance values ​​of the first end current collecting plate and the second end current collecting plate are determined according to the resistance value of the fourth sample assembly to be tested, the resistance value of the carbon felt layer, the contact resistance between the bipolar plate and the carbon felt layer, and the contact area between the bipolar plate and the carbon felt layer.

[0022] Furthermore, the lower end surface of the bipolar plate of the first end current collector plate contacts the third carbon felt layer, and the upper end surface of the bipolar plate of the second end current collector plate contacts the fourth carbon felt layer.

[0023] Further, measuring the resistance value of the first sample component to be tested, the second sample component to be tested, or the third sample component under a set pressure includes the following steps:

[0024] Metal pressure heads are respectively arranged at both ends of the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly, a set pressure is applied to the metal pressure heads by a press, and a milliohm resistance meter is connected to the first gold-plated electrode and the second gold-plated electrode in the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly, and the resistance value of the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly under the set pressure is measured by the milliohm resistance meter.

[0025] Further, measuring the resistance value of the first sample component to be tested, the second sample component to be tested, or the third sample component under a set pressure includes the following steps:

[0026] Metal pressure heads are respectively arranged at both ends of the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly, the two metal pressure heads are connected in series with a power supply and an ammeter, the two ends of the voltmeter are respectively connected to the first gold-plated electrode and the second gold-plated electrode in the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly, a set pressure is applied to the metal pressure heads by a press, a current is applied to the two metal pressure heads by a power supply, the current value flowing through the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly is measured by the ammeter, the voltage across the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly is measured by the voltmeter, and the resistance value of the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly under the set pressure is calculated according to the voltage value and the current value under the set pressure.

[0027] Further, measuring the resistance value of the fourth sample component to be tested includes the following steps:

[0028] Connect the two ends of the probe of the milliohm resistance meter to the first end current collecting plate and the second end current collecting plate respectively, and measure the resistance value of the fourth sample component to be tested.

[0029] Beneficial effects of the present invention:

[0030] 1. The end current collecting plate prepared by the present invention can make the two end faces of the end current collecting plate flat by applying a certain pressure through a press during the curing process of the conductive glue. The end current collecting plate includes a stacked metal plate, a conductive glue and a bipolar plate, so that the end current collecting plate has a high mechanical strength. The metal plate and the bipolar plate are connected by a conductive glue with a low resistivity, which can avoid the local gap between the metal plate and the bipolar plate, thereby causing the resistance value to increase. The resistance of the end current collecting plate prepared by the present invention is much smaller than that of other end current collecting plates buried with copper mesh, which effectively reduces the internal resistance of the battery stack and improves the efficiency of the battery stack.

[0031] 2. The resistance test method of the end current collecting plate of the present invention effectively solves the problem that the resistance of the end current collecting plate in the current flow battery cannot be measured, and provides a test standard for the calculation of the internal resistance of the battery stack and the study of its distribution.

[0032] Other features and advantages of the present invention will be described in the following description, and partly become obvious from the description, or be understood by implementing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0034] Figure 1 A schematic structural diagram of an end current collecting plate for a liquid flow battery according to an embodiment of the present invention is shown;

[0035] Figure 2 A schematic diagram of a contact resistance test structure between a bipolar plate and a carbon felt layer according to an embodiment of the present invention is shown;

[0036] Figure 3 A schematic diagram of a resistance test structure of an end current collecting plate according to an embodiment of the present invention is shown.

[0037] In the figure: 1. metal plate; 2. conductive glue; 3. bipolar plate; 4. first carbon felt layer; 5. second carbon felt layer; 6. first gold-plated electrode; 7. second gold-plated electrode; 8. metal pressure head; 9. power supply; 10. ammeter; 11. voltmeter; 12. first plate frame; 13. third carbon felt layer; 14. fourth carbon felt layer; 15. second plate frame. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] It should be noted that the terms "first", "second" etc. in the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged in appropriate circumstances, so that the embodiments of the present application described here. In the present application, the orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside", "outside", "middle", "vertical", "horizontal", "lateral", "longitudinal" etc. are based on the orientation or positional relationship shown in the accompanying drawings.

[0040] First, let's briefly explain the functions of the bipolar plates and end current collectors of the flow battery. The function of the bipolar plates is to connect the positive and negative electrodes of adjacent cells in series, conduct the internal circuit, block the electrolyte on both sides, and support the positive and negative electrodes. The function of the current collector is to support the electrodes on both sides and collect the conduction current.

[0041] The invention provides an end current collecting plate for a liquid flow battery and a preparation method thereof, so as to obtain an end current collecting plate with high mechanical lightness, good flatness and small resistance value.

[0042] like Figure 1 As shown, an end current collecting plate for a liquid flow battery includes a stacked metal plate 1, a conductive glue 2 and a bipolar plate 3, wherein the metal plate 1 can be made of copper or other metals, the conductive glue 2 includes but is not limited to conductive silver glue, conductive copper glue, epoxy metal glue, graphite conductive glue or graphite paste, and the thickness of the conductive glue 2 is 10um-100um.

[0043] The conductive adhesive 2 is an adhesive having a certain conductivity after curing or drying, and can connect a variety of conductive materials together to form an electrical path between the connected materials.

[0044] For example, the base resin of conductive silver glue is an adhesive, and a suitable curing temperature can be selected for bonding. For example, epoxy resin adhesive can be cured at room temperature to 150°C, which is much lower than the welding temperature of tin-lead soldering, which is above 200°C. This avoids the deformation of materials, thermal damage to electronic devices and the formation of internal stress that may be caused by high welding temperature. Epoxy metal glue is prepared by adding various additives and metal fillers to epoxy resin as the matrix. Graphite conductive glue is a conductive glue made by using graphite as a conductive additive2.

[0045] The conductive mechanism of the conductive adhesive 2 is as follows: before the conductive adhesive 2 is cured or dried, the conductive particles are separated in the adhesive and have no continuous contact with each other, thus being in an insulating state. During the curing process of the conductive adhesive 2, the volume of the adhesive shrinks due to the volatilization of the solvent and the curing of the adhesive, so that the conductive particles are in a stable continuous state with each other, thus showing conductivity.

[0046] The present invention also provides a method for preparing an end current collecting plate for a liquid flow battery, comprising the following steps:

[0047] S101, cleaning the metal plate 1 and the bipolar plate 3, cleaning the composite surface of the metal plate 1 and the bipolar plate 3, and ensuring that the contact surface of the metal plate 1, the bipolar plate 3 and the conductive adhesive 2 is free of debris.

[0048] S102, prepare conductive adhesive 2, weigh and prepare the conductive agent according to a set ratio, and mix them thoroughly and evenly.

[0049] S103 , quickly and evenly apply the conductive adhesive 2 to the lower end surface of the metal plate 1 or the upper end surface of the bipolar plate 3 .

[0050] S104, slowly sticking the upper end surface of the bipolar plate 3 to the lower end surface of the metal plate 1 to obtain a laminated plate structure.

[0051] S105, start the press to apply pressure to the upper and lower ends of the laminated plate structure according to the set pressure. For example, the set pressure of the press is 20T-100T / m 2 .

[0052] S106. During the process of applying pressure to the laminated plate structure, the laminated plate structure is heated, and after the conductive adhesive 2 is cured, an end current collecting plate is obtained.

[0053] The temperature for heating the laminated plate structure is determined according to the curing temperature of the conductive adhesive 2 .

[0054] The end current collecting plate of the present invention can make the two end surfaces of the end current collecting plate flat by applying a certain pressure through a press machine during the curing process of the conductive glue 2. The end current collecting plate includes a stacked metal plate 1, a conductive glue 2 and a bipolar plate 3, so that the end current collecting plate has a high mechanical strength, and the metal plate 1 and the bipolar plate 3 are connected by the conductive glue 2 with a low resistivity, which can avoid the presence of a local gap between the metal plate 1 and the bipolar plate 3, thereby causing an increase in resistance value.

[0055] The present invention also provides a method for testing the resistance of the end current collecting plate for the above-mentioned liquid flow battery, comprising the following steps:

[0056] S201, such as Figure 2 As shown, a first carbon felt layer 4 and a second carbon felt layer 5 are respectively laid on the upper and lower end surfaces of the bipolar plate 3, a first gold-plated electrode 6 is laid on the upper end of the first carbon felt layer 4, and a second gold-plated electrode 7 is laid on the lower end of the second carbon felt layer 5, to obtain a first sample assembly to be tested.

[0057] S202 , applying pressure to the upper and lower ends of the first sample component to be tested, and measuring the resistance value R1 of the first sample component to be tested under the set pressure.

[0058] S203 , removing the bipolar plate 3 in the middle of the first sample assembly to be tested, obtaining a second sample assembly to be tested, and measuring the resistance value R2 of the second sample assembly to be tested under a set pressure.

[0059] S204, removing the first carbon felt layer 4 or the second carbon felt layer 5 in the second sample assembly to be tested, obtaining a third sample assembly to be tested, measuring the resistance value of the third sample assembly to be tested under a set pressure, and obtaining the resistance value R of the carbon felt layer. C .

[0060] S205, determining the contact resistance R of the bipolar plate 3 and the first carbon felt layer 4 or the second carbon felt layer 5 according to the resistance value of the first sample assembly to be tested, the resistance value of the second sample assembly to be tested, the resistance value of the carbon felt, the resistance value of the bipolar plate 3, and the contact area between the bipolar plate 3 and the first carbon felt layer 4 or the second carbon felt layer 5. CB , as follows:

[0061] R1=2R C +2R CB / A+R B (1)

[0062] R2=2R C +R CC / A (2)

[0063]

[0064] In the formula, R C Indicates the resistance of the carbon felt layer, mΩ; R CC represents the contact resistance between the first carbon felt layer 4 and the second carbon felt layer 5, mΩ·cm 2 (negligible); R B Indicates the resistance of the bipolar plate 3, mΩ; R CB Represents the contact resistance between the bipolar plate 3 and the carbon felt layer, mΩ·cm 2 ; A represents the contact area between the bipolar plate 3 and the carbon felt layer, cm 2 .

[0065] The resistance value of the bipolar plate 3 is measured by a four-probe resistance method, which is as follows: four probes are placed on the surface of the bipolar plate 3, a DC signal is input to the bipolar plate 3, a voltage signal between the probes is collected, and the resistance of the bipolar plate 3 is obtained through a conversion relationship.

[0066] Wherein, measuring the resistance value of the first sample component to be tested, the second sample component to be tested, or the third sample component under a set pressure includes the following steps:

[0067] like Figure 2As shown, metal pressing heads 8 are respectively provided at both ends of the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly, a set pressure is applied to the metal pressing head 8 by a press machine, and a milliohm resistance meter is connected to the first gold-plated electrode 6 and the second gold-plated electrode 7 in the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly, and the resistance value of the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly under the set pressure is measured by the milliohm resistance meter.

[0068] or, as Figure 2 As shown, metal pressing heads 8 are respectively arranged at both ends of the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly, the two metal pressing heads 8 are connected in series with a power supply 9 and an ammeter 10 to form a test circuit, and the two ends of a voltmeter 11 are respectively connected to the first gold-plated electrode 6 and the second gold-plated electrode 7 in the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly, a set pressure is applied to the metal pressing heads 8 by a press, a current is applied to the two metal pressing heads 8 in the test circuit by the power supply 9, the current value flowing through the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly is measured by the ammeter 10, the voltage across the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly is measured by the voltmeter 11, and the resistance value of the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly under the set pressure is calculated according to the voltage value and the current value under the set pressure.

[0069] S206, such as Figure 3 As shown, two end collecting plates and two matching carbon felt layers, two plate frames, two end plates (not shown in the figure) and a plurality of bolt assemblies (not shown in the figure) are prepared.

[0070] S207, such as Figure 3 As shown, the first end plate, the first plate frame 12, the first end current collecting plate, the third carbon felt layer 13, the fourth carbon felt layer 14, the second end current collecting plate, the second plate frame 15 and the second end plate are stacked in sequence, and the first end plate and the second end plate are fixedly connected by multiple components to obtain a fourth sample assembly to be tested, wherein the lower end surface of the bipolar plate 3 of the first end current collecting plate contacts the third carbon felt layer 13, and the upper end surface of the bipolar plate 3 of the second end current collecting plate contacts the fourth carbon felt layer 14.

[0071] S208, connecting the two ends of the test leads of the milliohm resistance meter to the first end current collecting plate and the second end current collecting plate respectively, and measuring to obtain the resistance value R4 of the fourth sample component to be tested.

[0072] S209, determining the resistance value Rj (Rj) of the first end current collecting plate and the second end current collecting plate according to the resistance value of the fourth sample assembly to be tested, the resistance value of the carbon felt layer, the contact resistance between the bipolar plate 3 and the carbon felt layer, and the contact area between the bipolar plate 3 and the carbon felt layer. CB With R CThe value is determined according to the plate frame design compression ratio), as follows:

[0073] Rj=R4-2R c -2R CB *A

[0074] The first carbon felt layer 4, the second carbon felt layer 5, the third carbon felt layer 13 and the fourth carbon felt layer 14 in the present invention are all made of carbon fibers and have electrical conductivity.

[0075] The resistance of the end current collector plate prepared by the present invention is much smaller than that of other end current collector plates buried with copper mesh, which effectively reduces the internal resistance of the battery stack and improves the efficiency of the battery stack.

[0076] The resistance testing method of the end current collecting plate of the present invention effectively solves the problem that the resistance of the end current collecting plate in the current flow battery cannot be measured, and provides a testing standard for the calculation of the internal resistance of the battery stack and the research on its distribution.

[0077] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an end current collecting plate for a liquid flow battery, characterized in that: The following steps are involved: Cleaning metal plates and bipolar plates; preparing a conductive adhesive; Quickly and evenly apply the conductive glue to the lower end surface of the metal plate or the upper end surface of the bipolar plate; The upper end surface of the bipolar plate is slowly adhered to the lower end surface of the metal plate to obtain a laminated plate structure; Apply pressure to the upper and lower end surfaces of the composite plate structure according to the set pressure; In the process of applying pressure to the laminated plate structure, the laminated plate structure is heated, and after the conductive adhesive is cured, an end current collecting plate is obtained.

2. The method for preparing an end current collecting plate for a liquid flow battery according to claim 1, characterized in that: Set pressure: 20T-100T / m 2 .

3. The method for preparing an end current collecting plate for a liquid flow battery according to claim 1, characterized in that: The temperature for heating the laminated plate structure is determined according to the curing temperature of the conductive adhesive.

4. An end current collecting plate for a liquid flow battery, characterized in that: The end current collecting plate is prepared by the method for preparing the end current collecting plate for a liquid flow battery according to any one of claims 1 to 3.

5. The end current collecting plate for a liquid flow battery according to claim 4, characterized in that: It comprises a stacked metal plate, a conductive adhesive and a bipolar plate, wherein the metal plate is a copper plate.

6. The end current collecting plate for a liquid flow battery according to claim 5, characterized in that: Conductive adhesives include conductive silver adhesive, conductive copper adhesive, epoxy metal adhesive, graphite conductive adhesive or graphite paste.

7. The end current collecting plate for a liquid flow battery according to claim 5, characterized in that: The thickness of the conductive adhesive is 10um-100um.

8. A method for testing the resistance of an end current collector for a flow battery according to any one of claims 4 to 7, characterized in that: The following steps are involved: Laying a first carbon felt layer and a second carbon felt layer on the upper and lower end surfaces of the bipolar plate respectively, laying a first gold-plated electrode on the upper end of the first carbon felt layer, and laying a second gold-plated electrode on the lower end of the second carbon felt layer, to obtain a first sample assembly to be tested; Applying pressure to the upper and lower ends of the first sample component to be tested, and measuring the resistance value of the first sample component to be tested under the set pressure; Removing the bipolar plate in the middle of the first sample assembly to be tested to obtain a second sample assembly to be tested, and measuring the resistance value of the second sample assembly to be tested under a set pressure; removing the first carbon felt layer or the second carbon felt layer in the second sample assembly to be tested to obtain a third sample assembly to be tested, measuring the resistance value of the third sample assembly to be tested under a set pressure to obtain the resistance value of the carbon felt layer; Determine the contact resistance between the bipolar plate and the first carbon felt layer or the second carbon felt layer according to the resistance value of the first sample assembly to be tested, the resistance value of the carbon felt, the resistance value of the bipolar plate, and the contact area between the bipolar plate and the first carbon felt layer and the second carbon felt layer; The first end plate, the first plate frame, the first end current collecting plate, the third carbon felt layer, the fourth carbon felt layer, the second end current collecting plate, the second plate frame and the second end plate are stacked in sequence, and the first end plate and the second end plate are fixedly connected by a plurality of components to obtain a fourth sample assembly to be tested; Measuring the resistance value of the fourth sample component to be tested; The resistance values ​​of the first end current collecting plate and the second end current collecting plate are determined according to the resistance value of the fourth sample assembly to be tested, the resistance value of the carbon felt layer, the contact resistance between the bipolar plate and the carbon felt layer, and the contact area between the bipolar plate and the carbon felt layer.

9. The resistance test method of the end current collecting plate for a flow battery according to claim 8, characterized in that: The lower end surface of the bipolar plate of the first end current collector plate contacts the third carbon felt layer, and the upper end surface of the bipolar plate of the second end current collector plate contacts the fourth carbon felt layer.

10. The resistance testing method of the end current collecting plate for a flow battery according to claim 8, characterized in that: Measuring the resistance value of the first sample component to be tested, the second sample component to be tested, or the third sample component under a set pressure includes the following steps: Metal pressure heads are respectively arranged at both ends of the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly, a set pressure is applied to the metal pressure heads by a press, and a milliohm resistance meter is connected to the first gold-plated electrode and the second gold-plated electrode in the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly, and the resistance value of the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly under the set pressure is measured by the milliohm resistance meter.

11. The resistance test method of the end current collecting plate for a flow battery according to claim 8, characterized in that: Measuring the resistance value of the first sample component to be tested, the second sample component to be tested, or the third sample component under a set pressure includes the following steps: Metal pressure heads are respectively arranged at both ends of the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly, the two metal pressure heads are connected in series with a power supply and an ammeter, the two ends of the voltmeter are respectively connected to the first gold-plated electrode and the second gold-plated electrode in the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly, a set pressure is applied to the metal pressure heads by a press, a current is applied to the two metal pressure heads by a power supply, the current value flowing through the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly is measured by the ammeter, the voltage across the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly is measured by the voltmeter, and the resistance value of the first sample assembly to be tested, the second sample assembly to be tested or the third sample assembly under the set pressure is calculated according to the voltage value and the current value under the set pressure.

12. The resistance test method of the end current collecting plate for a flow battery according to claim 8, characterized in that: Measuring the resistance value of the fourth sample component to be tested includes the following steps: Connect the two ends of the probe of the milliohm resistance meter to the first end current collecting plate and the second end current collecting plate respectively, and measure the resistance value of the fourth sample component to be tested.

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