Electrolyzer stack comprising active compression, electrolysis system and method for operating electrolysis system

Abstract

An electrolyzer stack, an electrolysis system, and a method for operating an electrolysis system are provided. In one example, an electrolyzer stack includes an electrolysis cell block including a plurality of electrolysis cells configured to receive and convert water to form a hydrogen product stream. The electrolyzer stack includes a force applicator that, when pressurized, is configured to apply a force to the electrolysis cell block to counteract a dimensional change (e.g., expansion or contraction) of the electrolyzer stack. The force applied by the force applicator is based on the pressure of the hydrogen product stream.

Description

Technical Field

[0001] introduction

[0002] The present disclosure relates generally to electrolyzers, and more particularly to an electrolyzer stack including a cell block and a force applicator for applying force to the cell block, an electrolysis system including such an electrolyzer stack, and a method for operating such an electrolysis system. Background Art

[0003] An electrolyzer is an electrochemical device that converts water into hydrogen and oxygen using an electrolysis process. Electrolyzers are commonly used to produce hydrogen. Hydrogen is used in many industrial applications, such as, for example, the production of ammonia. Electrolyzers can be used for local production of hydrogen, for example as a fuel for vehicles equipped with hydrogen fuel cells. Electrolyzers can also be used to store energy from dynamic power sources, such as wind turbines and solar cells. Summary of the invention

[0004] An electrolyzer stack for an electrolysis system is provided. The electrolyzer stack includes an electrolyzer block, a force applicator, a pressure sensor, and a pressure source. The electrolyzer block includes a plurality of electrolyzers configured to receive and convert water to form a hydrogen product stream. The force applicator is configured to apply a force to the electrolyzer electrolyzer block when pressurized. The pressure sensor is configured to monitor the pressure of the hydrogen product stream. The pressure source is configured to pressurize the force applicator in response to the pressure of the hydrogen product stream.

[0005] In some embodiments, the pressure source includes a reservoir for containing a fluid, and wherein the pressure source is configured to fluidly communicate the fluid to the force applicator to pressurize the force applicator.

[0006] In some embodiments, the fluid is selected from water, nitrogen, or a hydraulic fluid.

[0007] In some embodiments, the force applicator is selected from a force applicator, a bladder, a piston, or a telescopic hydraulic actuator.

[0008] In some embodiments, the electrolyzer stack further includes a compression plate disposed between the force applicator and the electrolyzer block, wherein the force applicator, when pressurized, applies a force to the compression plate, which transmits the force to the electrolyzer block.

[0009] In some embodiments, the electrolyzer stack further includes a first end plate disposed adjacent to the force applicator and opposite the compression plate.

[0010] In some embodiments, the electrolyzer stack further includes a second end plate disposed adjacent to the electrolyzer block on a side opposite to the compression plate, wherein the first end plate and the second end plate are connected together to constrain expansion of the electrolyzer stack, including constraining expansion of the force applicator in a direction away from the electrolyzer block.

[0011] In some embodiments, the electrolyzer stack further includes a tension rod extending between the first end plate and the second end plate and at least partially connecting the first end plate and the second end plate together.

[0012] In some embodiments, the electrolyzer stack further includes a spring coupled to and cooperating with the tension rod to connect the first end plate and the second end plate together.

[0013] In some embodiments, the plurality of electrolytic cells respectively include a plurality of seals disposed between the compression plate and the second end plate and overlying each other to define a perimeter disposed about an active zone of the electrolytic cell block.

[0014] In some embodiments, the force applicator covers at least a portion of the active area of ​​the electrolytic cell block.

[0015] In some embodiments, the force applicator has an outermost periphery that substantially overlaps a perimeter defined by the plurality of seals.

[0016] In some embodiments, the force applicator has an outermost periphery that covers the active area inwardly of the perimeter defined by the plurality of seals.

[0017] In some embodiments, the electrolyzer stack further includes a pair of terminal plates including a first terminal plate disposed between the electrolyzer block and the compression plate, and a second terminal plate disposed between the electrolyzer block and the second end plate, wherein the force applicator covers the first terminal plate.

[0018] In some embodiments, the pair of terminal plates are configured to deliver electricity to the electrolyzer block to drive electrolysis of water to form a hydrogen product stream.

[0019] According to an alternative embodiment, an electrolysis system includes a water source, a power source, and an electrolyzer stack. The electrolyzer stack includes an electrolyzer block. The electrolyzer block includes a plurality of electrolyzers, which are fluidically connected to the water source to receive water and are connected to the power source to electrolyze water to form a hydrogen product stream. The electrolyzer stack further includes a force applicator configured to apply force to the electrolyzer block when pressurized. The electrolyzer stack further includes a pressure sensor configured to monitor the pressure of the hydrogen product stream. The electrolyzer stack further includes: a pressure source, which is fluidically connected to the force applicator; and a pressure controller, which communicates with the pressure sensor and is configured to direct the pressure source to pressurize the force applicator in response to the pressure of the hydrogen product stream.

[0020] In some embodiments, the electrolysis system further comprises power electronics in communication with the electrolyser stack and configured to control operation of the electrolyser block to produce the hydrogen product stream, and wherein the pressure controller forms part of or is independent of the power electronics.

[0021] In some embodiments, the electrolysis system further includes a recirculation stream in fluid communication with the electrolyzer stack and the water source to recirculate a remaining portion of the water from the electrolyzer stack to the water source.

[0022] In some embodiments, the electrolysis system is operably disposed in a vehicle.

[0023] According to an alternative embodiment, a method for operating an electrolysis system is provided. The method includes: introducing water to an electrolyzer stack including an electrolyzer block. The method further includes: electrolyzing the water in the electrolyzer block to form a hydrogen product stream. The method further includes: monitoring the pressure of the hydrogen product stream via a pressure sensor. The method further includes: directing a pressure source to pressurize a force applicator via a pressure controller, whereby the force applicator applies a force to the electrolyzer block in response to the pressure of the hydrogen product stream.

[0024] The present disclosure also provides the following technical solutions:

[0025] 1. An electrolyzer stack comprising:

[0026] an electrolyzer block comprising a plurality of electrolyzers configured to receive and convert water to form a hydrogen product stream;

[0027] a force applicator configured to apply a force to the electrolyzer cell block when pressurized;

[0028] a pressure sensor configured to monitor the pressure of the hydrogen product stream; and

[0029] A pressure source is configured to pressurize the force applicator in response to a pressure of the hydrogen product stream.

[0030] 2. The electrolyzer stack according to technical solution 1, wherein the pressure source includes a reservoir for containing a fluid, and wherein the pressure source is configured to fluidly deliver the fluid to the force applicator to pressurize the force applicator.

[0031] 3. An electrolyzer stack according to Technical Solution 2, wherein the fluid is selected from water, nitrogen or hydraulic fluid.

[0032] 4. The electrolyzer stack according to Technical Solution 1, wherein the force applicator is selected from a force applicator, a bladder, a piston or a telescopic hydraulic actuator.

[0033] 5. The electrolyzer stack according to Technical Solution 1 further comprises a compression plate arranged between the force applicator and the electrolytic cell block, wherein the force applicator applies the force to the compression plate when pressurized, and the compression plate transfers the force to the electrolytic cell block.

[0034] 6. The electrolyzer stack according to Technical Solution 5 further comprises a first end plate, which is arranged adjacent to the force applicator and opposite to the compression plate.

[0035] 7. The electrolyzer stack according to Technical Solution 6 further includes a second end plate, which is arranged adjacent to the electrolyzer block on a side opposite to the compression plate, wherein the first end plate and the second end plate are connected together to constrain the expansion of the electrolyzer stack, including constraining the expansion of the force applicator in a direction away from the electrolyzer block.

[0036] 8. The electrolyzer stack according to Technical Solution 7 further comprises a stretch rod extending between the first end plate and the second end plate and at least partially connecting the first end plate and the second end plate together.

[0037] 9. The electrolyzer stack according to technical solution 8 further comprises a spring, which is connected to the tension rod and cooperates with it to connect the first end plate and the second end plate together.

[0038] 10. An electrolyzer stack according to Technical Solution 7, wherein the plurality of electrolytic cells respectively include a plurality of seals, which are disposed between the compression plate and the second end plate and cover each other to define a perimeter disposed around an active area of ​​the electrolytic cell block.

[0039] 11. The electrolyzer stack according to technical solution 10, wherein the force applicator covers at least a portion of the active area of ​​the electrolytic cell block.

[0040] 12. An electrolyzer stack according to technical solution 11, wherein the force applicator has an outermost periphery, and the outermost periphery substantially overlaps with the perimeter defined by the plurality of seals.

[0041] 13. The electrolyzer stack according to technical solution 11, wherein the force applicator has an outermost periphery, and the outermost periphery covers the active area on the inner side of the perimeter defined by the plurality of seals.

[0042] 14. The electrolyzer stack according to Technical Solution 7 further includes a pair of terminal plates, the pair of terminal plates including a first terminal plate arranged between the electrolytic cell block and the compression plate, and a second terminal plate arranged between the electrolytic cell block and the second end plate, wherein the force applicator covers the first terminal plate.

[0043] 15. The electrolyzer stack according to technical solution 14, wherein the paired terminal plates are configured to deliver electricity to the electrolyzer blocks to drive the electrolysis of water, thereby forming the hydrogen product stream.

[0044] 16. An electrolysis system comprising:

[0045] Water source;

[0046] power supply;

[0047] An electrolyzer stack, the electrolyzer stack comprising:

[0048] an electrolyzer block comprising a plurality of electrolyzers in fluid communication with the water source to receive water and in communication with the power source to electrolyze the water to form a hydrogen product stream;

[0049] a force applicator configured to apply a force to the electrolytic cell block when pressurized;

[0050] a pressure sensor configured to monitor the pressure of the hydrogen product stream; and

[0051] a pressure source in fluid communication with the force applicator; and

[0052] A pressure controller is in communication with the pressure sensor and is configured to direct the pressure source to pressurize the force applicator in response to a pressure of the hydrogen product stream.

[0053] 17. The electrolysis system according to technical solution 16 further includes a power electronic device, which is connected to the electrolyzer stack and is configured to control the operation of the electrolyzer block to produce the hydrogen product flow, and wherein the pressure controller forms a part of the power electronic device or is independent of the power electronic device.

[0054] 18. The electrolysis system according to technical solution 16 further comprises a recirculation flow, which is connected to the electrolyzer stack and the water source fluid to recirculate the remaining portion of water from the electrolyzer stack to the water source.

[0055] 19. An electrolysis system according to technical solution 16, wherein the electrolysis system is operably arranged in a vehicle.

[0056] 20. A method for operating an electrolysis system, the method comprising:

[0057] introducing water into an electrolyser stack including electrolyser blocks;

[0058] electrolyzing water in the electrolyzer block to form a hydrogen product stream;

[0059] monitoring the pressure of the hydrogen product stream via a pressure sensor;

[0060] A pressure source is directed via a pressure controller to pressurize a force applicator, whereby the force applicator applies a force to the electrolyzer block in response to the pressure of the hydrogen product stream.

[0061] The above features and advantages and other features and advantages of the present disclosure are readily apparent from the following detailed description of the best modes for carrying out the disclosure when taken in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 is a schematic illustration of an electrolysis system according to one or more embodiments of the present disclosure.

[0063] Figure 2 is a schematic top view of a portion of an electrolysis system including an electrolyzer stack according to one or more embodiments of the present disclosure.

[0064] Figure 3 yes Figure 2 A cross-sectional view of the electrolyzer stack depicted in FIG. 3 along line 3 - 3 .

[0065] Figure 4 is a flow chart of a method for operating an electrolysis system according to one or more embodiments of the present disclosure.

[0066] The accompanying drawings are not necessarily drawn to scale and may present somewhat simplified representations of various preferred features of the present disclosure as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes. The details associated with such features will be determined in part by the specific intended application and use environment. DETAILED DESCRIPTION

[0067] As required, detailed embodiments of the present disclosure are disclosed herein; however, it will be understood that the disclosed embodiments are merely examples of the present disclosure, which may be embodied in various and alternative forms. The figures are not necessarily drawn to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, the specific structural and functional details disclosed herein are not to be construed as limiting, but merely as a representative basis for teaching those skilled in the art to adopt the present disclosure in various ways.

[0068] Unless otherwise stated from the context, as used herein, the term "about" should be understood to be within the normal tolerance range in the art, such as within 2 standard deviations of the mean. "About" can be understood to be within 10%, 5%, 1%, 0.5%, 0.1%, 0.05% or 0.01% of the value. "About" can alternatively be understood to imply the exact value stated. Unless otherwise clear from the context, the numerical values ​​provided herein are modified by the term "about".

[0069] Electrolyzers are classified into three main types: alkaline electrolyzers, solid oxide electrolyzers, and proton exchange membrane (PEM) electrolyzers. Alkaline electrolyzers use alkaline solutions as electrolytes, such as potassium hydroxide (KOH) or sodium hydroxide (NaOH). Solid oxides use solid ceramic materials as electrolytes that conduct oxygen ions at high temperatures (typically about 800°C to 1000°C). In one example, a PEM electrolyzer includes an electrolyzer block formed by a plurality of stacked electrolyzers (e.g., in series), wherein each electrolyzer includes various components, including various membrane electrode assembly (MEA) components. The MEA components include a solid polymer membrane (i.e., a proton exchange membrane or PEM) disposed between an anode and a cathode. The MEA components constituting the cathode include a catalyst layer disposed adjacent to a gas diffusion layer (GDL). Similarly, the MEA components constituting the anode include a catalyst layer disposed adjacent to a porous transport layer (PTL). The PEM selectively allows positively charged hydrogen ions to pass through the membrane between the anode and the cathode (as part of the electrolysis process) to convert water into hydrogen and oxygen.

[0070] The PEM electrolyzer can be designed to apply a force (e.g., a compressive force) to the electrolyzer block during operation to counteract the increased pressure (s) generated by converting liquid water to hydrogen gas, thereby operating more efficiently. This force helps prevent hydrogen leakage and reduces contact resistance along the electrolyzer block by counteracting dimensional changes (e.g., expansion or contraction) in the stack length (e.g., stack height) of the PEM electrolyzer. Changes in the stack length of the PEM electrolyzer may be caused, for example, by swelling, thermal expansion, and / or creep of various components, such as, for example, one or more of the sealing gaskets that seal the electrolyzers in the electrolyzer block and / or various MEA components within the electrolyzer block. Some of the current designs are inefficient due to swelling, thermal expansion, creep, and / or high pressure.

[0071] In high pressure electrolyzers, for example, where hydrogen pressures of up to 30 bar (3 MPa) or more may be generated, the problem or concern of hydrogen leakage and / or reduced electrolysis efficiency may be further increased. In such electrolyzers, the increased pressure also increases the hardware used to apply forces to offset the dimensional changes in the stack length of the electrolyzer. The additional hardware increases the stack volume, weight, and design complexity of the electrolyzer.

[0072] Therefore, it is desirable to provide an electrolyzer stack that solves one or more of the above problems, an electrolysis system including such an electrolyzer stack, and a method for operating such an electrolysis system. In addition, other desirable features and characteristics of the various embodiments described herein will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background.

[0073] The present disclosure relates generally to electrolyzers, and more particularly to an electrolyzer stack including an electrolyzer block and a force applicator for applying a force to the electrolyzer block, an electrolysis system including such an electrolyzer stack, and a method for operating such an electrolysis system.

[0074] In one or more embodiments of the present disclosure, the electrolyzer stack includes an electrolyzer block including a plurality of electrolyzers configured to receive and convert water to form a hydrogen product stream. The force applicator is configured to apply force to the electrolyzer block (i.e., the electrolyzer electrolyzer block) when pressurized by a pressure source. The pressure source is configured to pressurize the force applicator in response to the pressure of the hydrogen product stream. A pressure sensor (e.g., a sensor, a sensor arrangement, or other device for sensing pressure) is configured to monitor the pressure of the hydrogen product stream. A pressure control member can be used to communicate with the pressure sensor and the pressure source.

[0075] In one or more embodiments of the present disclosure, the electrolyzer stack is part of an electrolysis system. The electrolysis system further includes a water source and a power source, which are configured to communicate with the electrolyzer stack. During operation of the electrolysis system, liquid water is fluidly delivered to the electrolyzer stack from the water source, and electricity is delivered to the electrolyzer stack from the power source. The electrolyzer stack uses electricity to convert liquid water feedstock to produce a hydrogen product stream via electrolysis. A pressure sensor monitors the pressure of the hydrogen product stream and communicates with a pressure controller. The pressure controller communicates with a pressure source in response to the pressure of the hydrogen product stream and directs the pressure source to pressurize a force applicator. The force applicator applies force to the electrolyzer block when pressurized by the pressure source.

[0076] In the exemplary embodiment, advantageously, hydrogen leakage is reduced, minimized or prevented and electrolysis in the electrolyzer block is improved due to the higher force(s) applied by the force applicator to counteract any dimensional changes in the electrolyzer block and / or electrolyzer stack.

[0077] In another exemplary embodiment, if creep (e.g., compression deformation, etc.) has occurred in one or more of the electrolyzer block components, the effects of the creep are reduced, minimized, or eliminated because the force applicator applies force to the electrolyzer block to compensate for the effects of the creep. Since the force applicator pressure can simultaneously compensate for the effects of dimensional changes in the electrolyzer block components and offset the internal hydrogen pressure of the electrolyzer stack, the length of the electrolyzer stack will be adjusted accordingly to ensure close contact between adjacent electrolyzer block components.

[0078] Figure 1 is a schematic view of an electrolysis system 10 according to one or more embodiments of the present disclosure. As illustrated, the electrolysis system 10 includes a water source 20 in fluid communication with an electrolyzer stack 40 via a line 22 to provide a water feedstock to the electrolyzer stack 40. Any unused, excess, and / or byproduct water is returned from the electrolyzer stack 40 to the water source 20 via a recirculation flow line 44. Additionally, a power source 30 and power electronics 50 are in communication with the electrolyzer stack 40 via lines 32 and 52, respectively.

[0079] Additionally, pressure controller 70 is in communication with pressure sensor 60 and pressure source 80. Pressure sensor 60 (e.g., a sensor, sensor arrangement, or other device for sensing pressure) is configured to monitor the hydrogen product stream 44 advancing through hydrogen product line 42 (at Figure 3 The pressure is shown in FIG.

[0080] The pressure controller 70 is configured to direct the pressure source 80 to apply force to the electrolyzer stack 40 in response to the pressure of the hydrogen product stream 44. Figure 3 The pressure controller 70 is pressurized by the power electronics 50 (shown in and discussed below). The pressure source 80 is in fluid communication with the electrolyzer stack 40 via the conduit 82 and is configured to pressurize the force applicator 110 of the electrolyzer stack 40. The force applicator 110 is configured to apply a force when pressurized to offset the dimensional change of the length (i.e., height) of the electrolyzer stack 40. The pressure controller 70 may form part of the power electronics 50, or may be independent of the power electronics 50.

[0081] The pressure controller 70 may be embodied as one or more digital computers or data processing devices, each having one or more microprocessors or central processing units (CPUs), read-only memory (ROM), random access memory (RAM), electrically erasable programmable read-only memory (EEPROM), high-speed clocks, analog-to-digital (A / D) circuitry, digital-to-analog (D / A) circuitry, input / output (I / O) circuitry, power electronics / transformers, and / or signal conditioning and buffering electronics. The various control routines / systems resident in or readily accessible to the pressure controller 70 may be stored in a ROM or other suitable tangible memory location and / or memory device and automatically executed by the associated hardware components of the pressure controller 70 to provide the corresponding control functions.

[0082] In one or more embodiments of the present disclosure, the hydrogen storage device 90 is in fluid communication with the electrolyzer stack 40 via the hydrogen product line 42 to receive hydrogen product produced during electrolysis in the electrolyzer stack 40 , as will be discussed in further detail below.

[0083] As illustrated, electrolyzer stack 40 receives electricity (i.e., electric current) from power source 30 via line 32 and water from water source 20 via line 22. Electrolyzer stack 40 converts water from water source 20 into hydrogen and oxygen via electrolysis using the electricity supplied by power source 30. Hydrogen is produced as hydrogen product stream 44 (at Figure 3 ) is output from the electrolyzer stack 40 and advances to the hydrogen storage device 90 via pipeline 42.

[0084] During operation of the electrolysis system 10, the power source 30 supplies direct current to the electrolyzer stack 40. Examples of power sources include, but are not limited to, batteries, solar cells, DC generators, wind turbines, hydroelectric power plants, and / or the like.

[0085] The power electronics 50 are in communication with the electrolyzer stack 40 and are configured to control the operation of the electrolyzer stack 40. For example, the power electronics 50 may control the amount of voltage and current supplied from the power source 30 to the electrolyzer stack 40.

[0086] Figure 2 is a schematic top view of a portion of an electrolysis system 10 including an electrolyzer stack 40 according to one or more embodiments of the present disclosure. Figure 3 yes Figure 2 A cross-sectional view of the electrolyzer stack 40 depicted in FIG. 4 is taken along line 3 - 3 . Figures 1 to 3 In one or more embodiments of the present disclosure, the electrolyzer stack 40 includes an electrolyzer block 100 and a force applicator 110. The electrolyzer block 100 includes a plurality of electrolyzers 102 (e.g., electrolyzer electrolyzers) configured to receive and convert water to form a hydrogen product stream 44. The force applicator 110 is configured to apply force to the electrolyzer block 100 indirectly or directly based on the pressure of the hydrogen product stream 44 to offset the dimensional change of the length (i.e., height) of the electrolyzer block 100.

[0087] The plurality of electrolytic cells 102 include a plurality of seals 104 and a plurality of separator plates 150. The electrolytic cells in the plurality of electrolytic cells 102 are stacked into an electrolytic cell block 100 and electrically connected in series. Each electrolytic cell in the plurality of electrolytic cells 102 includes various components including a membrane electrode assembly (MEA), a pair of separator plates, and a pair of seals.

[0088] The pair of separator plates (from the plurality of separator plates 150) contain flow channels that interface with the MEA and allow fluids (e.g., water, hydrogen, and oxygen) to flow to or from the MEA. Each separator plate is conductive and facilitates electron transport to help establish an electrical circuit for the electrolysis process.

[0089] The MEA includes a solid polymer membrane (i.e., a proton exchange member or PEM), an anode (i.e., an anode-catalyst layer), and a cathode (i.e., a cathode-catalyst layer). The PEM is disposed between the anode-catalyst layer and the cathode-catalyst layer. The cathode-catalyst layer is disposed adjacent to a gas diffusion layer (GDL). Likewise, the anode-catalyst layer is disposed adjacent to a porous transport layer (PTL). The PEM contains an active zone in which an electrochemical reaction occurs via electrolysis to convert water into hydrogen. The PEM selectively allows positively charged hydrogen ions to pass through the membrane between the anode and cathode (as part of the electrolysis process) to convert water into hydrogen and oxygen.

[0090] Each electrolyzer is structured so that the MEA is disposed between the pair of separator plates. The pair of seals (from the plurality of seals 104) prevents fluid (e.g., water, hydrogen, and oxygen) from leaking from the interface between the MEA and the pair of separator plates. The pair of seals defines the MEA perimeter 109 (at Figure 2 ). The MEA perimeter 109 is the area where the fluid is restricted before exiting the MEA via the pair of separator plates.

[0091] The MEA perimeter 109 is associated with the perimeter area 106. The perimeter area 106 is the area defined by the plurality of seals 104 and the MEA perimeter 109 of each of the plurality of seals 104. In other words, the MEA perimeter 109 is associated with the electrolytic cells, and the perimeter area 106 is associated with the plurality of electrolytic cells 102.

[0092] As illustrated, electrolyzer stack 40 receives water from water source 20 via conduit 22 and receives electrical current from power source 30 via conduit 32. Electrolyzer stack 40 may receive electrical current via wiring, busses, and / or electrical connectors (not shown) that are electrically coupled to terminal block 210 (e.g., a first terminal block), for example.

[0093] Water advances into and through the electrolyzer block 100 via the water inlet 160, which feeds the plurality of electrolyzers 102 via the plurality of separator plates 150. The terminal plates 210 and 220, the plurality of separator plates 150, and each MEA in the plurality of electrolyzers 102 form an electrical circuit that drives the electrolysis process when current is applied to the electrolyzer block 100. When current passes through the plurality of electrolyzers 102 between the terminal plates 210 and 220, the water advancing in the plurality of electrolyzers 102 is converted into hydrogen and oxygen via the electrolysis process.

[0094] As illustrated, oxygen and any unused, excess and / or byproduct water is removed from the plurality of electrolytic cells 102 via a water oxygen outlet 180. The water oxygen outlet 180 forwards the removed water to the recirculation flow line 44 which delivers the water back to the water source 20.

[0095] The hydrogen gas produced in the plurality of electrolyzers 102 proceeds to a hydrogen header 170. The hydrogen gas exits the electrolyzer stack 40 from the hydrogen header 170 to form a hydrogen product stream 44. The hydrogen product stream 44 proceeds through a hydrogen product line 42.

[0096] Pressure sensor 60 measures the pressure of hydrogen product stream 44 advancing through hydrogen product line 42. Pressure sensor 60 transmits pressure data associated with hydrogen product stream 44 to pressure controller 70. Since hydrogen product stream 44 is formed from hydrogen produced during the electrolysis process, the pressure of hydrogen product stream 44 is equal to or substantially equal to the internal pressure of electrolyzer stack 40.

[0097] The pressure controller 70 receives the pressure data and calculates the total force (i.e., the force applied to the internal structure of the electrolyzer stack 40 due to the hydrogen pressure) using the following equation:

[0098] F H2 =P H2 xA H2 , (1)

[0099] where F H2 represents the total force from the hydrogen pressure within the electrolyzer stack 40, P H2 represents the hydrogen pressure associated with the pressure data, and A H2 is the area defined by the perimeter area 106. H2 are the same because all of the electrolyzer cells in the plurality of electrolyzer cells are identical and are operated as Figure 3 The aligned configuration shown in the stack.

[0100] The pressure controller 70 then calculates the pressure required to pressurize the force applicator 110 to offset the dimensional change in the stack length of the electrolyzer using the following equation:

[0101] P A =(F H2 +F 基线 ) / A A , 2)

[0102] Where P A represents the pressure required to pressurize the force applicator 110, the total force F H2 represents the total force from the hydrogen pressure within the electrolyzer stack 40, F 基线 represents the stack compression force (i.e., stack force) required for sealing pressure (i.e., pressure required to maintain the seal of the sealing gasket (and / or the like) to prevent fluid leakage) and low electrical contact resistance when the hydrogen pressure is zero, and A A F represents the area of ​​the force applicator 110 that is in physical contact with the compression plate 120. 基线The stack force is typically applied when the electrolyzer stack 40 is assembled before hydrogen production begins. The assembly may include (as discussed in more detail below) a tension rod 190 and optionally a spring 200 (i.e., stack spring(s)) extending between and at least partially connecting the end plates 130 and 140 of the electrolyzer stack 40 to constrain or compress the components of the electrolyzer stack 40. In the case where the stack springs are used to maintain the stack force from dimensional changes of the components due to bulging, thermal expansion, and / or creep, F need not be considered when controlling the force applicator 110. 基线 , and therefore F 基线 can be considered as zero in Equation 2.

[0103] Total force (i.e., F H2 Add F 基线 ) is applied to the compression plate of the electrolyzer block 100 to maintain the seal 104 to prevent water and product gas leakage while counteracting the increased pressure(s) generated by converting liquid water into hydrogen gas. The total force also enhances the conductivity of the electrolyzer block 100 by reducing electrical contact resistance. Electrical contact resistance is the resistance to the flow of electrical current at the electrical connection points (i.e., the interfaces among the plurality of electrolyzers 102 and the components of the electrolyzer).

[0104] Next, the pressure controller 70 directs the pressure source 80 to pressurize or adjust the internal pressure of the force applicator 110. The pressure source 80 includes a reservoir for containing a fluid. The fluid may be water, nitrogen, hydraulic fluid, and / or the like.

[0105] When the force applicator 110 is pressurized, the force applicator 110 applies a force (e.g., a compressive force or a force in the direction of the electrolyzer block 100) directly or indirectly to a compression plate 120 (e.g., a movable compression plate) that facilitates evenly distributing and transmitting the force to the electrolyzer block 100. As illustrated, the compression plate 120 is disposed adjacent to and between the force applicator 110 and the electrolyzer block 100.

[0106] The amount of force applied by the force applicator 110 depends on the total force F H2 and F 基线. The force applied by the force applicator 110 is a reaction force to the total force from the hydrogen pressure located within the electrolyzer stack 40. Since the portion of the force of the force applicator 110 that is used to offset the force from the hydrogen pressure is equal or substantially equal in magnitude, the compression plate 120 remains stationary when the hydrogen pressure changes during hydrogen production. Therefore, the length of the electrolyzer stack 40 does not change with changes in hydrogen pressure, thereby remaining substantially dimensionally stable. Further, if creep (e.g., compression deformation, etc.) has occurred in one or more of the electrolyzer block 100 components (e.g., seal 104, etc.), then since the force applicator pressure is equal to the internal pressure of the electrolyzer stack 40, the length of the electrolyzer stack 40 will be adjusted accordingly to ensure close contact between the electrolyzer block 100 components.

[0107] In some embodiments, the electrolyzer stack 40 includes an electrolyzer block 100, a compression plate 120, a force applicator 110, an end plate 130 (e.g., a first end plate), an end plate 140 (e.g., a second end plate), a hydrogen product line 42, a pressure sensor 60, a pressure controller 70, a pressure source 80, a tension rod 190, a spring 200, a terminal plate 210, a terminal plate 220, the plurality of electrolyzers 102, and a plurality of seals 104.

[0108] As briefly discussed above, the plurality of electrolyzers 102 respectively include the plurality of seals 104, which cover each other to define a perimeter region 106 disposed around an active zone 108 of the electrolyzer block 100. As used herein, an "active zone" is understood to mean an area or region in which an electrochemical reaction occurs via electrolysis to convert water into hydrogen. As illustrated, the force applicator 110 covers the active zone 108 of the electrolyzer block 100. As used herein, the term "covering" is understood to mean that in one or more orientations of the electrolyzer block 100, the force applicator 110 is located above the electrolyzer block 100, while in other orientations, although the force applicator 110 may not be located above the electrolyzer block 100, the force applicator 110 is directly or indirectly adjacent to the electrolyzer block 100.

[0109] As illustrated, the electrolytic cell block 100 is disposed adjacent to and between the terminal plates 210 and 220. On a side of the terminal plate 210 opposite the electrolytic cell block 100, the compression plate 120 is disposed adjacent to and between the terminal plate 210 and the force applicator 110. Further and as illustrated, the force applicator 110 is disposed adjacent to and between the compression plate 120 and the end plate 130. The end plate 130 is disposed adjacent to the force applicator 110 and opposite the compression plate 120.

[0110] As discussed above, the force applicator 110, when pressurized, applies force to the compression plate 120, which transmits the force to the electrolytic cell block 100. In one or more embodiments of the present disclosure, the force applicator 110 applies force over an area of ​​the force applicator 110 that is in physical contact with the compression plate 120. The area (i.e., the force applicator area) is the portion of the force applicator 110 that is in physical contact with the compression plate 120.

[0111] The force applicator 110 can be a force applicator, a bladder, a piston, a telescopic hydraulic actuator, and / or the like. In an exemplary embodiment, the bladder is formed of or otherwise includes an elastic material that can expand and contract without significant plastic deformation. Further, in an exemplary embodiment, the bladder may include accordion-shaped folded walls (e.g., pleated or foldable wall segments) that overlap each other to form one or more "V" shapes or folded shapes when the bladder is not pressurized or in a collapsed position. When the bladder 80 is pressurized, the accordion-shaped folded walls expand, for example, the foldable wall segments (e.g., (multiple) "V" shaped folded shapes) unfold to increase the length of the wall. Non-limiting examples of elastic materials suitable for forming the force applicator 110 include polymer materials (such as rubber and fiber-reinforced thermoplastic polymers) or metals (such as stainless steel and aluminum).

[0112] On the side of the electrolyzer block 100 opposite the force applicator 110, the terminal plate 220 is disposed adjacent to and between the electrolyzer block 100 and the end plate 140. The terminal plates 210 and 220 (i.e., a pair of terminal plates) are electrically conductive to allow electricity to pass through to the electrolyzer block 100, thereby driving the electrolysis of water to form the hydrogen product stream 44.

[0113] As illustrated, the hydrogen product stream 44 passes through openings or conduits in the end plate 140. The hydrogen product stream 44 is formed from hydrogen produced by the electrolysis of water.

[0114] In some embodiments, the electrolyzer stack 40 does not include the spring 200. Instead, the electrolyzer stack 40 includes an electrolyzer block 100, a compression plate 120, a force applicator 110, an end plate 130 (e.g., a first end plate), an end plate 140 (e.g., a second end plate), a hydrogen product line 42, a pressure sensor 60, a pressure controller 70, a pressure source 80, a tension rod 190, a terminal plate 210, a terminal plate 220, the plurality of electrolyzers 102, and the plurality of seals 104.

[0115] In this embodiment, since spring 200 is not included in electrolyzer stack 40, force applicator 110 is required to take into account F 基线 , as discussed above in equation (2). 基线The pressure may be predetermined based on the characteristics of the electrolyzer stack 40, such as the active zone (or active area) of the electrolyzer stack 40 and the pressure associated with the active zone (or active area). The pressure may range from about 0.2 MPa to about 3 MPa, but is typically in the range of about 1 MPa to about 2 MPa. In some embodiments, the pressure may exceed about 3 MPa.

[0116] Alternatively, F may be determined based on the pressure value of the initial operating state of the electrolyzer stack 40. 基线 For example, before the electrolyzer stack 40 produces hydrogen, the force applicator 100 applies a force (e.g., an initial or nominal force) to the compression plate 120. The electrolyzer stack 40 then receives electricity and begins to produce hydrogen gas, wherein the pressure of the hydrogen gas is measured by the pressure sensor 60. The initial pressure measurement of the hydrogen gas is used to calculate the initial force. The initial force is combined with the force from the force applicator 100 to determine F 基线 The initial pressure measurement of hydrogen may occur over a short duration (eg, approximately 30 seconds).

[0117] In an exemplary embodiment, the force applicator 110 has an outermost periphery that substantially overlaps the perimeter defined by the plurality of seals 104. In an exemplary embodiment, the force applicator 110 has an outermost periphery that covers an active area inwardly of the perimeter defined by the plurality of seals 104.

[0118] In the exemplary embodiment, tension rods 190 and springs 200 (i.e., stack springs) are coupled and cooperate to compress electrolyzer block 100 by connecting end plates 130 and 140 together. End plates 130 and 140 are connected together to constrain expansion of electrolyzer stack 40, including constraining expansion of force applicator 110 in a direction away from electrolyzer block 100. In the exemplary embodiment, this helps ensure that force applicator 110 directs force toward electrolyzer block 100 when pressurized.

[0119] In the exemplary embodiment, tension rod 190 and spring 200 further assist in providing additional force to electrolyzer stack 40 to ensure that a certain degree of force is always applied to the plurality of seals 104 and active area 108 despite any pressure fluctuations and / or dimensional changes that may occur in electrolyzer block 100 during operation and / or startup of electrolysis system 10.

[0120] In the exemplary embodiment, tension rod 190 (excluding spring 200) extends between and at least partially connects end plates 130 and 140. End plates 130 and 140 are connected together to constrain expansion of electrolyzer stack 40, including constraining expansion of force applicator 110 in a direction away from electrolyzer block 100. In the exemplary embodiment, this helps ensure that force applicator 110 directs force toward electrolyzer block 100 when pressurized.

[0121] Figure 4 is a flow chart of a method 400 for operating an electrolysis system 10 according to one or more embodiments of the present disclosure. The method 400 includes introducing (step 410) water to an electrolyzer stack 40 including an electrolyzer block 100.

[0122] The method 400 continues by electrolyzing (step 420) water in an electrolyzer block to form a hydrogen product stream. The method 400 continues by monitoring (step 430) the pressure of the hydrogen product stream via a pressure sensor.

[0123] The method 400 continues by directing (step 440) the pressure source via a pressure controller to pressurize the force applicator in response to the pressure of the hydrogen product stream. When pressurized, the force applicator applies force to the electrolyzer block to offset the dimensional change of the length (i.e., height) of the electrolyzer stack. Although the best mode for carrying out the present disclosure has been described in detail, those skilled in the art to which the present disclosure relates will recognize various alternative designs and embodiments for practicing the present disclosure within the scope of the appended claims.

[0124] In an exemplary embodiment, the electrolysis system 10 is incorporated into or otherwise used in a vehicle (e.g., a motor vehicle). As used herein, "vehicle" is understood to mean a device configured for transporting people, things, objects, or the like. Non-limiting examples of motor vehicles (e.g., internal combustion engine (ICE) vehicles, electric vehicles, including electric battery vehicles and fuel cell vehicles, or the like) include land vehicles (e.g., cars, trucks, motorcycles, electric bicycles, buses, trains, or the like), air vehicles (e.g., airplanes, helicopters, unmanned aerial vehicles, or the like), water vehicles (e.g., boats, watercraft, or the like), and amphibious vehicles (e.g., hovercraft, or the like).

[0125] Any of the dimensions, configurations, etc. discussed herein may be varied as needed or desired from any value or characteristic specifically mentioned herein or shown in the figures for any embodiment.

[0126] It will be apparent to those skilled in the art that various modifications and variations may be made to the embodiments of the apparatus and assembly methods as discussed herein without departing from the scope or spirit of the (multiple) disclosures. Other embodiments of the present disclosure will be apparent to those skilled in the art in view of the specification and the practice of the various embodiments disclosed herein. For example, some equipment may be constructed and operated differently than described herein, and certain steps of any method may be omitted, performed in an order different from the order specifically mentioned, or in some cases performed simultaneously or in sub-steps. In addition, certain aspects or features of the various embodiments may be changed or modified to produce further embodiments, and the features and aspects of the various embodiments may be added to or substituted for other features or aspects of other embodiments to provide further embodiments.

Claims

1. An electrolyzer stack comprising: an electrolyzer block comprising a plurality of electrolyzers configured to receive and convert water to form a hydrogen product stream; a force applicator configured to apply a force to the electrolyzer cell block when pressurized; a pressure sensor configured to monitor a pressure of the hydrogen product stream; as well as A pressure source is configured to pressurize the force applicator in response to a pressure of the hydrogen product stream.

2. The electrolyzer stack according to claim 1, wherein: The pressure source includes a reservoir for containing a fluid, and wherein the pressure source is configured to fluidly deliver the fluid to the force applicator to pressurize the force applicator.

3. The electrolyzer stack according to claim 2, wherein: The fluid is selected from water, nitrogen or hydraulic fluid.

4. The electrolyzer stack according to claim 1, wherein: The force applicator is selected from a force applicator, a bladder, a piston or a telescopic hydraulic actuator.

5. The electrolyzer stack of claim 1, further comprising a compression plate disposed between the force applicator and the electrolyzer block, wherein: The force applicator, when pressurized, applies the force to the compression plate, which transmits the force to the electrolytic cell block.

6. The electrolyzer stack of claim 5, further comprising a first end plate disposed adjacent to the force applicator and opposite the compression plate.

7. The electrolyzer stack of claim 6, further comprising a second end plate disposed adjacent to the electrolyzer block on a side opposite to the compression plate, wherein: The first end plate and the second end plate are connected together to constrain expansion of the electrolyzer stack, including constraining expansion of the force applicator in a direction away from the electrolyzer block.

8. The electrolyzer stack of claim 7, further comprising a tension rod extending between the first end plate and the second end plate and at least partially connecting the first end plate and the second end plate together.

9. The electrolyzer stack of claim 8, further comprising a spring coupled to the tension rod and cooperating therewith to connect the first and second end plates together.

10. The electrolyzer stack of claim 7, wherein: The plurality of electrolytic cells respectively include a plurality of seals disposed between the compression plate and the second end plate and overlying one another to define a perimeter disposed about an active area of ​​the electrolytic cell block.

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