Integrated assembly, electrochemical reaction device, and method of manufacture

Abstract

The present disclosure provides an integrated assembly, an electrochemical reaction device, and a preparation method, wherein the preparation method of the integrated assembly comprises: providing a bipolar plate and a porous transport layer to be integrated, aligning the bipolar plate in contact with the porous transport layer, welding the bipolar plate and the porous transport layer in contact with each other, and forming a nitride on the surface of the porous transport layer. By integrating the bipolar plate and the porous transport layer, the electrical conductivity and the thermal conductivity can be improved, and a nitride protective layer is provided.

Description

Technical Field

[0001] This disclosure relates to the field of electrochemical reaction device technology, specifically to an integrated component, an electrochemical reaction device, and a preparation method thereof. Background Technology

[0002] An electrochemical reaction device is a device or apparatus that realizes an electrochemical reaction, including water electrolyzers (e.g., proton exchange membrane (PEM) water electrolyzers, anion exchange membrane (AEM) water electrolyzers), fuel cells, electroplating, and other electrochemical reaction devices for various applications. Electrochemical reaction devices typically include a porous transport layer (PTL) and bipolar plates; however, the performance of electrochemical reaction devices in related technologies in terms of electrical conductivity and / or thermal conductivity remains unsatisfactory. Summary of the Invention

[0003] After long-term research, the inventors unexpectedly discovered that the electrical conductivity and / or thermal conductivity of an electrochemical reaction device with bipolar plates and a porous transport layer, and with a nitride protective layer, can be improved by following the steps below.

[0004] Therefore, based on the above findings, in a first aspect, this disclosure provides a method for fabricating an integrated component, comprising: providing a bipolar plate to be integrated and a porous transport layer; contact-aligning the bipolar plate and the porous transport layer; welding the contact-aligned bipolar plate and the porous transport layer together; and forming a nitride on the surface of the porous transport layer.

[0005] The inventors discovered that by combining bipolar plates and porous transport layers together, i.e. integrating them, the performance of electrochemical reaction devices with bipolar plates and porous transport layers can be improved, such as increasing the electrical conductivity and / or thermal conductivity of the electrochemical reaction device. At the same time, nitrides can be formed on the surface of the porous transport layer for protection.

[0006] In some embodiments, welding the contact-aligned bipolar plate and the porous transport layer together, and forming a nitride on the surface of the porous transport layer, includes: welding the contact-aligned bipolar plate and the porous transport layer together in an inert atmosphere; and nitriding the welded bipolar plate and the porous transport layer in a nitrogen atmosphere to form a nitride on the surface of the porous transport layer. That is, the welding of the bipolar plate and the porous transport layer, and the surface nitriding of the porous transport layer, can be achieved in two steps.

[0007] In some embodiments, welding the contact-aligned bipolar plate and the porous transport layer together, and forming a nitride on the surface of the porous transport layer, includes: welding the contact-aligned bipolar plate and the porous transport layer together under a nitrogen atmosphere, and forming a nitride on the surface of the porous transport layer during the welding process. That is, the welding of the bipolar plate and the porous transport layer, as well as the surface nitriding of the porous transport layer, can be achieved in one step.

[0008] In some embodiments, after aligning the bipolar plate with the porous transport layer, the method further includes applying a preset clamping force to the aligned bipolar plate and the porous transport layer. In some embodiments, after aligning the bipolar plate with the porous transport layer, a plate clamp is used to hold and press the bipolar plate and the porous transport layer.

[0009] In some embodiments, the contact-aligned bipolar plates and the porous transport layer are welded together, and a nitride is formed on the surface of the porous transport layer, in a nitrogen-filled gas-tight chamber. In some embodiments, the pressure inside the gas-tight chamber is greater than the pressure outside the gas-tight chamber.

[0010] In some embodiments, the contact-aligned bipolar plates and the porous transport layer are welded together, and a nitride is formed on the surface of the porous transport layer, by means of laser scanning. In some embodiments, the airtight chamber is provided with a laser source.

[0011] In another aspect of this disclosure, an integrated component prepared by the method of this disclosure is provided.

[0012] In another aspect of this disclosure, an electrochemical reaction apparatus is provided, which includes the integrated components of this disclosure.

[0013] In another aspect of this disclosure, a method for preparing an electrochemical reaction device is also provided, comprising: preparing an integrated component by the method of this disclosure, and assembling the electrochemical reaction device based on the integrated component.

[0014] In another aspect of this disclosure, an integrated component is provided, comprising a bipolar plate and a porous transport layer, the bipolar plate and the porous transport layer being integrated in one component through direct contact.

[0015] In some embodiments, there is no gap between the bipolar plate and the porous transport layer.

[0016] In some embodiments, the porous transport layer and the bipolar plate are in direct contact to form a flat plate structure.

[0017] In some embodiments, the thickness of the integrated component is 50-5000 micrometers. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this disclosure or related technologies, the accompanying drawings used in describing this disclosure or related technologies will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without any inventive effort.

[0019] Figure 1 This is a cross-sectional schematic diagram showing the stack of electrochemical reaction devices.

[0020] Figure 2 This is a comparative schematic diagram of a conventional stack containing bipolar plates and porous transport layers, and an integrated stack containing bipolar plates and porous transport layers. Figure 2 a is a schematic diagram showing a typical stack containing bipolar plates and a porous transport layer; Figure 2 b is a schematic diagram showing an integrated stack including bipolar plates and a porous transport layer.

[0021] Figure 3 Photographs of two common types of porous transport layers in proton exchange membrane water electrolyzers in related technologies are shown, where a) is a porous transport layer sintered with titanium particles; and b) is a porous transport layer sintered with titanium fibers.

[0022] Figure 4 This is a 3D schematic diagram of a laboratory welding fixture used for laser welding and laser nitriding processes of bipolar plates and porous transport layers. The left image is an overall view, and the right image shows an enlarged view of the cross-section of the device.

[0023] Figure 5 This is a schematic diagram of one embodiment of the present disclosure, in which the laser head and the welding fixture are both placed in an airtight cavity filled with pure nitrogen.

[0024] Figure 6 This is a schematic diagram of an embodiment of laser scanning using a fixture disclosed herein.

[0025] Figure 7 This is a flowchart of one embodiment of the method for preparing the integrated component disclosed herein. Detailed Implementation

[0026] To better illustrate the technical means and effects of this disclosure, the following description, in conjunction with non-limiting examples, further describes the disclosure. The embodiments of this disclosure (including the descriptions provided in the embodiments) are intended to illustrate the implementation of this disclosure and are not intended to limit the scope of any claim. Based on this disclosure, those skilled in the art will understand that many changes can be made to the specific embodiments disclosed without departing from the spirit and scope of this disclosure, and the same or similar results can still be obtained.

[0027] Unless otherwise stated, the terms used in this specification and claims have the following meanings.

[0028] In this document, the term "bipolar plate" or "plate" can refer to an anode plate and / or a cathode plate, and a bipolar plate can consist of a cathode plate (a single cathode plate) and an anode plate (a single anode plate), or it can refer to a single plate. In this document, "plate" and "bipolar plate" are used interchangeably, and "bipolar plate" can be used to express the meaning of a single plate.

[0029] In some embodiments, the bipolar plate is a metal plate, i.e., a metal-based plate, such as a titanium substrate. The titanium substrate may contain other metallic or non-metallic components besides metallic titanium, such as a titanium alloy plate; or, the titanium substrate may contain only metallic titanium, such as a pure titanium plate. In some embodiments, the alloying metal of the titanium alloy is composed of metals selected from titanium, chromium, nickel, aluminum, tantalum, zirconium, tungsten, and niobium. In some embodiments, the titanium alloy is a titanium-chromium alloy, a titanium-aluminum alloy, a titanium-vanadium alloy, a titanium-nickel alloy, a titanium-chromium-aluminum alloy, a titanium-chromium-vanadium alloy, a titanium-aluminum-vanadium alloy, a titanium-nickel-chromium alloy, a titanium-nickel-aluminum alloy, or a titanium-nickel-vanadium alloy. In some embodiments, the bipolar plate in this disclosure is a titanium metal plate (i.e., a pure titanium metal plate); in some embodiments, the bipolar plate in this disclosure is a titanium-based stainless steel bipolar plate.

[0030] In this article, "integration" refers to combining different components together. Therefore, the integrated assembly based on bipolar plates and porous transport layers in this article refers to an assembly formed by combining bipolar plates and porous transport layers. Integration can lead to improvements in cost and / or performance. For example, integration eliminates the interface between the bipolar plate and the porous transport layer, which is beneficial for improving the electrical and thermal conductivity of both. Additionally, integration can improve the mechanical properties of the porous transport layer, allowing the use of thinner plates (e.g., less than 500 micrometers) at higher pressure differentials (e.g., up to 20 bar). Furthermore, integration can reduce manufacturing costs.

[0031] In this document, a nitrogen atmosphere refers to an atmosphere in which nitrogen is the basic component. In some embodiments, the nitrogen atmosphere contains essentially no oxygen, for example, less than 5%, 4%, 3%, 2%, or 1% oxygen. In some embodiments, the nitrogen atmosphere is essentially pure nitrogen, for example, the nitrogen atmosphere contains at least 95%, 96%, 97%, 98%, or 99% nitrogen. A nitrogen atmosphere may contain nitrogen and optionally a rare gas (e.g., argon).

[0032] In this disclosure, "plate-like structure" refers to a plate-like or sheet-like structure, or a structure that is substantially plate-like or sheet-like.

[0033] In the description of this specification, references to terms such as "some embodiments," "some examples," "for example," or "implementation" mean that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the above terms are illustrative. Furthermore, the specific features, structures, materials, or characteristics described may be combined in suitable manner in any one or more embodiments or examples. Moreover, those skilled in the art can combine different embodiments or examples described in this specification, as well as combine features of different embodiments or examples, unless they are contradictory.

[0034] With regard to the method for preparing the integrated component of this disclosure, in some embodiments, such as Figure 7 As shown, the fabrication method includes: providing a bipolar plate to be integrated and a porous transport layer; aligning the bipolar plate and the porous transport layer in contact; welding the aligned bipolar plate and the porous transport layer together; and forming a nitride on the surface of the porous transport layer.

[0035] In this example, by combining the bipolar plate and the porous transport layer together, i.e. integrating them together, the performance of an electrochemical reaction device with a bipolar plate and a porous transport layer can be improved, such as increasing the electrical conductivity and / or thermal conductivity of the electrochemical reaction device. At the same time, nitrides can be formed on the surface of the porous transport layer to prevent corrosion of the porous transport layer, etc., for protection.

[0036] In some implementations, welding contact-aligned bipolar plates and a porous transport layer together and forming a nitride on the surface of the porous transport layer includes: welding the contact-aligned bipolar plates and the porous transport layer together in an inert atmosphere; and nitriding the welded bipolar plates and the porous transport layer in a nitrogen atmosphere to form a nitride on the surface of the porous transport layer. For example, the contact-aligned bipolar plates and the porous transport layer can be welded together first in an argon atmosphere, for example, using laser welding; then, the welded bipolar plates and the porous transport layer can be nitrided in a nitrogen atmosphere, for example, using laser nitriding, to form a nitride. In this example, the welding of the bipolar plates and the porous transport layer, and the surface nitriding of the porous transport layer, can be achieved in two steps.

[0037] In other embodiments, the contact-aligned bipolar plates and the porous transport layer are welded together, and a nitride is formed on the surface of the porous transport layer. This includes welding the contact-aligned bipolar plates and the porous transport layer together in a nitrogen atmosphere, and forming a nitride on the surface of the porous transport layer during the welding process. For example, the contact-aligned bipolar plates and the porous transport layer can be welded together in a nitrogen atmosphere, such as using laser welding. Since the welding occurs in a nitrogen atmosphere, a nitride can be formed simultaneously during the welding process. In this example, the welding of the bipolar plates and the porous transport layer, as well as the surface nitriding of the porous transport layer, can be achieved in one step.

[0038] In the example above, by carefully controlling the welding parameters, a highly stoichiometric and robust nitride (e.g., titanium nitride, TiN) layer can be formed as a protective layer during the welding process. The highly stoichiometric nitride (e.g., TiN) layer helps prevent hydrogen diffusion into the metal (e.g., titanium) and avoids hydrogen embrittlement. The nitride layer also prevents oxidation of the metal (e.g., titanium). This means there is no need to apply expensive coatings to prevent internal corrosion.

[0039] Based on this, another unexpected aspect of this disclosure is the discovery that a high-quality nitride (e.g., TiN) layer can be directly formed during the welding process of the porous transport layer and the bipolar plate, thereby achieving many advantageous technical effects, such as avoiding the use of expensive coatings as protective layers; avoiding additional coating steps; and so on.

[0040] In some embodiments, welding the contact-aligned bipolar plates and the porous transport layer together, and forming a nitride on the surface of the porous transport layer, is performed in a nitrogen-filled gas-tight chamber. Exemplarily, the gas-tight chamber is filled with 85%, 90%, 95%, 96%, 97%, 98%, 99%, or 100% nitrogen. In some embodiments, the pressure inside the gas-tight chamber is greater than the pressure outside the gas-tight chamber. Exemplarily, the pressure of the gas-tight chamber is higher than the ambient pressure, for example, the gas-tight chamber has a pressure at least 50 mbar, 100 mbar, 150 mbar, 200 mbar, 300 mbar, 400 mbar, or 500 mbar higher than the ambient pressure.

[0041] In some embodiments, the welding is resistance welding or laser welding, such as laser welding. In some embodiments, laser welding is performed in a nitrogen atmosphere. For laser welding in a nitrogen atmosphere, laser welding and laser nitriding (i.e., the formation of a nitride protective layer, such as a titanium nitride protective layer) are performed simultaneously, thereby simplifying the process and reducing production costs; in some embodiments, laser welding can be performed using a single laser source or multiple laser sources, wherein the multiple laser sources can be at least two, three, four, five or more laser sources.

[0042] For example, laser welding in a nitrogen atmosphere can be used to simultaneously perform laser welding and laser nitriding (forming a nitride protective layer, such as a titanium nitride protective layer), with the thickness of the formed nitride (such as titanium nitride) protective layer being 5 to 10 micrometers.

[0043] The above method combines the two steps of forming the nitride protective layer and laser welding into one step. Specifically, laser welding can be performed in a nitrogen atmosphere to form a nitride (e.g., titanium nitride) protective layer on the plate surface while integrating the porous transport layer and bipolar plate. This reduces the need for cleaning and pretreatment of the plate surface, which typically involves degreasing, descaling, and deoxidizing the monopolar plate using dilute sulfuric acid, acetone, ethanol, distilled water, etc. This significantly reduces the number of processing steps and costs.

[0044] In the method of this disclosure, the laser can be generated by a suitable laser generating device. The laser can have a wavelength or average wavelength of 800 nm to 1200 nm, 400 nm to 550 nm, or 300 nm to 400 nm. In the method of this disclosure, integrating the porous transport layer and the bipolar plate into a single component is beneficial for improving the thermal conductivity at the interface between the porous transport layer and the bipolar plate, thereby resulting in a more uniform current distribution in the catalyst layer region. This integration can be achieved through simple and inexpensive welding techniques (e.g., resistance welding or laser welding).

[0045] In some implementations, the airtight chamber is equipped with a laser source, which can be a diode fiber laser, an ultraviolet diode laser, or a CO2 laser, etc. For efficiency and cost-effectiveness, a diode fiber laser can be selected as the light source. The airtight chamber can simultaneously house one or more identical or different laser sources. In this case, laser welding and laser nitriding of the bipolar plate and porous transmission layer are performed using the laser source within the nitrogen-filled airtight chamber.

[0046] In some embodiments, the contact-aligned bipolar plate and porous transport layer are welded together, and a nitride is formed on the surface of the porous transport layer, by laser scanning. For example, the bipolar plate and porous transport layer can be laser-welded and laser-nitrided by one or more laser scans. Exemplarily, the laser scans can be performed at least 2, 3, 4, 5, 6, 7, 8, 9, 10, or more times. In some embodiments, the laser scan movement speed is 0.5 mm / s to 20 mm / s, or 1 mm / s to 15 mm / s, or 2 mm / s to 10 mm / s, and the movement speed is relative to the scanning direction.

[0047] In this disclosure, the laser used can be a nanosecond, picosecond, or femtosecond pulsed source. Femtosecond pulsed sources offer high efficiency and minimal thermal deformation; nanosecond pulsed sources require less equipment. The laser used in the laser nitriding process can be a continuous source or a nanosecond or picosecond pulsed source.

[0048] In some embodiments, the surface temperature of the porous transport layer during laser welding and / or laser nitriding ranges from 900°C to 2500°C, or 1000°C to 2200°C, or 1200°C to 2000°C. Exemplarily, the upper surface temperature of the porous transport layer can be adjusted to a range of 900°C to 2500°C by adjusting welding parameters during laser welding, such as welding power. In some embodiments, the laser power is 1 to 5 kW, and / or the laser welding time does not exceed 1 minute.

[0049] While other techniques, such as sintering, can be used to create a robust bond between the porous transport layer and the bipolar plate, their cost is significantly too high. Laser welding offers advantages due to its simplicity and consistency. The use of high-power diodes and fiber lasers can further reduce costs and provides advantages in energy efficiency and process yield.

[0050] The method disclosed herein can be implemented quickly and easily using laser welding. For example, for bipolar plates of average size, the entire process of laser welding the porous transport layer and the bipolar plate under a nitrogen atmosphere can be completed in 50-100 cm⁻¹. 2 The process is completed at a speed of / s. The typical laser power required ranges from 1KW to 5KW.

[0051] In some implementations, after aligning the bipolar plate with the porous transport layer, the process further includes applying a preset clamping force to the aligned bipolar plate and porous transport layer to ensure tight contact. For example, the bipolar plate and porous transport layer can be first brought into contact and aligned; the alignment position is not limited and is determined according to actual needs. Then, a plate clamp (e.g., a titanium plate clamp) is used to hold the aligned bipolar plate and porous transport layer, and the clamping force of the plate clamp is adjusted to apply the preset clamping force to the aligned bipolar plate and porous transport layer, thereby clamping the bipolar plate and porous transport layer to ensure good interface contact, facilitating integration after welding and further improving performance. The preset clamping force is set according to actual needs and is not limited here.

[0052] In implementing the method of this disclosure, to ensure good contact between the metal components, a clamp equipped with compression bolts and a transparent fused silica window can be used to apply a pressure of 0.1 to 1 MPa to allow laser transmission while clamping, such as... Figure 4-5As shown. The graphite base serves as the heat dissipation medium in direct contact with the bipolar plate. Nitrogen gas is supplied to the inlet of the bipolar plate at a pressure of ≥0.2 bar through orifices in the graphite base.

[0053] In continuous laser welding, fixtures can be customized according to the porous transport layer and bipolar plate to be integrated to better implement the methods of this disclosure. In some embodiments of the fabrication methods of this disclosure, the porous transport layer and bipolar plate can be contact-aligned and placed on a fixture, and the contact-aligned porous transport layer and bipolar plate can be held by the fixture during the welding process. Figure 6 An embodiment of this disclosure using a fixture for laser scanning is illustrated. Laser scanning can be achieved by moving either the laser head or the welding fixture, or both in reverse. If a pulsed laser is used instead of a continuous-wave laser, the laser head and welding fixture do not move, and the galvanometer system integrated within the laser head projects the desired pattern along the surface. Although an optimized pulsed laser can be used in this process, a continuous-wave laser is preferred due to its simplicity and lower cost.

[0054] In some implementations, a transparent component, such as a fused silicon plate, may be placed above the bipolar plate and the porous transport layer after the contact is established, to press the bipolar plate and the porous transport layer together.

[0055] According to the integrated component fabrication method disclosed herein, after integrating the bipolar plate and the porous transport layer, there is no longer a gap between the porous transport layer and the bipolar plate, thereby eliminating or reducing the associated contact resistance. Furthermore, coating treatment at the interface between the bipolar plate and the porous transport layer is no longer required, significantly reducing raw material and processing costs. Additionally, the thermal conductivity at the interface between the bipolar plate and the porous transport layer is also improved. The mechanical strength of the anode porous transport layer is improved, allowing the use of thinner plates (e.g., less than 500 micrometers thick) at operating pressures up to 20 bar. The stack assembly process is simplified due to the integration of the bipolar plate and the anode porous transport layer.

[0056] In some embodiments, the method may further include depositing an additional protective or functional layer over the nitride layer after the nitride layer has been formed. This additional protective or functional layer may be deposited on a portion of the surface. This step is not mandatory and may be selected based on actual needs.

[0057] This paper describes a method for fabricating an integrated assembly based on a bipolar plate and a porous transport layer, enabling the integration of the porous transport layer and the bipolar plate. The bipolar plate can be pre-formed as needed, and the forming design refers to engraving ridges and grooves on one side (front) of the metal plate to create a pre-designed flow channel pattern. In some embodiments, the bipolar plate can be produced using automated forming and welding technology, in which case the integration of the porous transport layer and the bipolar plate can be performed after the bipolar plate welding is completed. In some embodiments, the integration of the porous transport layer and the bipolar plate directly participates in the bipolar plate welding process, meaning that the integration can be performed directly during the bipolar plate fabrication process, which implies a further reduction in processing costs.

[0058] In another aspect, this disclosure provides an integrated component prepared by the method described above.

[0059] In another aspect, this disclosure provides an electrochemical reaction apparatus incorporating the integrated components of this disclosure. See also Figure 1 The diagram shows a stack of electrochemical reaction devices. 1 is a component containing a separator layer, an anode, and a cathode catalyst layer; in some applications (such as fuel cells and water electrolyzers), this component is called a Catalyst Coated Membrane (CCM). 2 and 3 are porous transport layers, one located between the anode and component 1, and the other between the cathode and component 1. 4 is an electrode plate.

[0060] Figure 2 a is a schematic diagram of a typical stack containing bipolar plates and porous transport layers, where 1 is an assembly containing a separator layer, an anode, and a cathode catalyst layer. In some applications (such as fuel cells and water electrolyzers), this assembly is referred to as a CCM; 2 and 3 are porous transport layers, one located at the anode and the other at the cathode; 4 is a bipolar plate; and 5 is an optional coating prepared on the surfaces of the bipolar plate, the anode, and the cathode porous transport layers.

[0061] Figure 2 b is a schematic diagram showing the integrated stack of bipolar plates and porous transport layers, compared to Figure 2 a) This eliminates the physical interface between the bipolar plate and the porous transport layer, meaning there is no physical interface between the bipolar plate and one side of the porous transport layer, thus eliminating the need for additional plating. 7) is a metal nitride layer on the surface of the metal porous transport layer. Other coatings may optionally be plated onto its surface as needed.

[0062] In another aspect of this disclosure, a method for preparing an electrochemical reaction device is provided, comprising: fabricating an integrated component based on a bipolar plate and a porous transport layer by means of the method of this disclosure; and assembling the electrochemical device using the integrated component based on the bipolar plate and the porous transport layer.

[0063] The electrochemical reaction apparatus disclosed herein can be selected from proton exchange membrane (PEM) water electrolyzers, alkaline water electrolyzers, anion exchange membrane (AEM) water electrolyzers, fuel cells, and carbon dioxide emission reduction devices.

[0064] Figure 3 Photographs are shown of two common types of porous transport layers in proton exchange membrane water electrolyzers (PEMWEs) in related technologies, wherein Figure 3 a shows a porous transport layer sintered from titanium particles. Figure 3 b shows a titanium fiber sintered porous transport layer.

[0065] On the other hand, an integrated component is provided comprising a bipolar plate and a porous transport layer, the bipolar plate and the porous transport layer being integrated in one component through direct contact. In some embodiments, there is no gap between the bipolar plate and the porous transport layer. Exemplarily, the bipolar plate and the porous transport layer are in direct contact such that there is no gap between them.

[0066] In some implementations, the porous transport layer is in the form of a titanium-based mesh or a perforated titanium plate. Exemplary examples include sintered titanium particle porous transport layers or sintered titanium fiber porous transport layers.

[0067] In some embodiments, the porous transport layer and the bipolar plate are in direct contact to form a planar structure. In other embodiments, part or all of the porous transport layer is in direct contact with the bipolar plate to form a planar structure.

[0068] In some implementations, the thickness of the integrated component is 50-5000 micrometers. For example, the thickness of the integrated component is 50-1000 micrometers, 50-500 micrometers, 50-400 micrometers, or 50-300 micrometers.

[0069] In some implementations, the thickness of the bipolar plate can be between 50 and 5000 micrometers, and the thickness of the porous transport layer can be between 100 and 500 micrometers. The thickness of the bipolar plate as a metal plate can be from 20 micrometers to 5000 micrometers, for example, 50 micrometers, 100 micrometers, 200 micrometers, 300 micrometers, 400 micrometers, 500 micrometers, 600 micrometers, 700 micrometers, 800 micrometers, 900 micrometers, or 1000 micrometers.

[0070] The porous transport layer in this disclosure can be made of any suitable material. In some embodiments, the porous transport layer is made of a metallic material or a metal-dominant material. Exemplarily, the porous transport layer is a titanium substrate. In the case where the titanium substrate is made of a titanium alloy, in some embodiments, titanium constitutes a mass percentage greater than 75%, greater than 80%, greater than 85%, greater than 90%, or even greater than 95% of the alloy. The alloy material can be an alloy composed of a major component element and minor component elements. In some embodiments, the major component element is titanium, and the minor component elements are selected from one or more of tungsten, molybdenum, zirconium, chromium, niobium, vanadium, iron, silicon, carbon, and other trace impurities.

[0071] This disclosure achieves at least one of the following beneficial technical effects: 1. The integration of bipolar plates and porous transport layers, along with the disappearance of the interface, is beneficial for improving the electrical and thermal conductivity of both the bipolar plates and porous transport layers. ·2. Using a nitrogen atmosphere as a protective atmosphere for the welding process, a nitride layer is formed on the porous transport layer and bipolar plate integration, which allows for the use of thinner coatings (such as PGM (platinum group metals) coatings), and even eliminates the need for expensive coatings as a modification layer, while also preventing hydrogen embrittlement and oxidation; 3. Due to the elimination of the physical interface between the porous transport layer and the bipolar plate, the resistance is reduced, and when it is used in electrochemical reaction devices, such as batteries, the performance of the electrochemical reaction devices is improved accordingly. 4. It can improve the mechanical properties of porous transport layers, allowing the use of thinner porous transport layers (e.g., less than 500 micrometers thick) under pressure differentials of up to 20 bar. 5. The integration of bipolar plates and porous transport layers simplifies the stack assembly process; 6. The process is fast and efficient, utilizing laser welding of the porous transport layer and bipolar plate, which can be completed in 1-2 minutes; 7. When bipolar plates are manufactured using a stamping and welding process, the integration of the bipolar plate and the porous transport layer can be combined with the bipolar plate manufacturing process, thereby further reducing costs.

[0072] Furthermore, the method disclosed herein can provide ready-to-use plates. In contrast to processes in related technologies, the integrated assembly of bipolar plates and porous transport layers manufactured by this method can be directly used in electrochemical reaction devices (e.g., water electrolyzers or fuel cells), thus facilitating expansion and custom configuration according to process requirements.

[0073] The method disclosed herein can be used to form high-quality nitride protective layers (e.g., TiN layers). In particular, the resulting TiN layers are highly crystallizable and conformally preserved. The TiN layers are mainly composed of osbornite (stoichiometric TiN), and their thickness can vary between 5 micrometers and 10 micrometers. Example

[0074] Example 1: Fabrication of an integrated component based on a bipolar plate and a porous transport layer

[0075] The fabrication process of the integrated component based on the porous transport layer and bipolar plate involves two main steps to obtain a robust and durable single component. The laser source can be a continuous wave or pulsed laser. Although different laser sources can be used, the preferred wavelength is 1064 nm. The atmosphere can be controlled in two different ways. One way is to place both the laser and the welding fixture within a hermetically sealed cavity filled with pure nitrogen; another method of supplying nitrogen is through a graphite base, which reduces the amount of waste gas and speeds up the process. While this requires machining the graphite base to create openings for gas transport, this method allows for the application of higher nitrogen pressures, thereby improving diffusion kinetics.

[0076] This embodiment employs, as follows: Figure 5 The method shown belongs to the first category mentioned above. See also... Figure 5 The laser head and welding fixture are housed in a sealed chamber filled with nitrogen at a pressure of 0.1–0.5 bar. The graphite base aids in heat dissipation and prevents unwanted reactions between the bipolar plates and the steel base plate.

[0077] The first step in this process is to align and compress the porous transport layer and bipolar plate using a steel shell with fused silica optical windows. Pressure is applied to ensure good contact between the welded components. For example, a pressure of 1 MPa can be applied using compression bolts on the steel frame.

[0078] Once the weldment makes good contact, the laser beam passes through the molten silica plate and is projected onto the surface of the porous transport layer. The laser power is sufficient to approach the melting point of the metal, but the temperature is slightly below the melting point (90%). When using a continuous-wave laser, multiple scans can be performed to ensure a good weld. Typical scan speeds are 4 to 20 mm / s, with a single scan covering the entire area.

[0079] Laser scanning can be achieved by moving the laser head or the welding fixture, or both in reverse. See [link to documentation]. Figure 6 If a pulsed laser is used instead of a continuous-wave laser, the laser head and welding fixture do not need to move, and the galvanometer system integrated within the laser head projects the desired pattern along the surface. Although optimized pulsed lasers can be used in this process, continuous-wave lasers offer the advantages of simplicity and lower cost.

Claims

1. A method for fabricating an integrated component, characterized in that, include: Provides bipolar plates and porous transport layers to be integrated; Align the bipolar plate with the porous transport layer in contact; The contact-aligned bipolar plate and the porous transport layer are welded together, and a nitride is formed on the surface of the porous transport layer.

2. The method according to claim 1, characterized in that, The step of welding the contact-aligned bipolar plate and the porous transport layer together, and forming a nitride on the surface of the porous transport layer, includes: Under an inert atmosphere, the contact-aligned bipolar plates and the porous transport layer are welded together; Under a nitrogen atmosphere, the welded bipolar plates and porous transport layer are nitrided to form nitrides on the surface of the porous transport layer.

3. The method according to claim 1, characterized in that, The step of welding the contact-aligned bipolar plate and the porous transport layer together, and forming a nitride on the surface of the porous transport layer, includes: Under a nitrogen atmosphere, the contact-aligned bipolar plate and the porous transport layer are welded together, and nitrides are formed on the surface of the porous transport layer during the welding process.

4. The method according to any one of claims 1-3, characterized in that, After aligning the bipolar plate with the porous transport layer, the method further includes applying a preset clamping force to the aligned bipolar plate and the porous transport layer.

5. The method according to any one of claims 1-3, characterized in that, The welding of the contact-aligned bipolar plates and the porous transport layer together, and the formation of nitride on the surface of the porous transport layer, are carried out in an airtight chamber filled with nitrogen.

6. The method according to any one of claims 1-3, characterized in that, The process of welding the contact-aligned bipolar plates and the porous transport layer together, and forming a nitride on the surface of the porous transport layer, is performed by laser scanning.

7. An integrated component prepared by the method according to any one of claims 1 to 6.

8. An electrochemical reaction apparatus, characterized in that, Includes the integrated component as described in claim 7.

9. A method for preparing an electrochemical reaction device, characterized in that, include: The integrated component is prepared by the method according to any one of claims 1 to 6; The electrochemical reaction device is assembled based on the integrated components.

10. An integrated component, characterized in that, It comprises: a bipolar plate and a porous transport layer, wherein the bipolar plate and the porous transport layer are integrated in a single component through direct contact.

11. The integrated component according to claim 10, characterized in that, There is no gap between the bipolar plate and the porous transmission layer.

12. The integrated component according to claim 10 or 11, characterized in that, The porous transport layer and the bipolar plate form a flat plate structure through direct contact.

13. The integrated component according to claim 10 or 11, characterized in that, The thickness of the integrated component is 200-5000 micrometers.

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