Reinforcing layer for improving metal bump seal buckling load and pressure uniformity

Abstract

The present disclosure relates to a bipolar plate. The bipolar plate comprises an anode plate and a cathode plate. The anode plate has an inner side and an outer side opposite the inner side. The cathode plate has an inner side and an outer side opposite the inner side. And the inner side surface of the cathode plate faces the inner side of the anode plate. The bipolar plate includes a raised region. A portion of the inner side of the anode plate at the raised region is spaced apart from a portion of the inner side of the cathode plate at the raised region. The reinforcing layer is disposed between the inner side of the anode plate and the inner side of the cathode plate at the raised region. The reinforcement layer is configured to resist compressive forces experienced at the outboard of the anode plate and at the outboard of the cathode plate at the raised regions.

Description

Technical Field

[0001] The information provided in this section is for the purpose of generally presenting the context of the present disclosure. The work of the presently named inventors, to the extent it is described in this section and insofar as it may not qualify as prior art at the time of filing, is neither explicitly nor implicitly admitted as prior art to the present disclosure.

[0002] The present disclosure generally relates to fuel cell systems for vehicles, and more particularly to bipolar plates for separating adjacent fuel cells in a fuel cell system. Specifically, the present disclosure provides a bipolar plate for a vehicle fuel cell system having an anode plate and a cathode plate, wherein a reinforcement layer or structure is disposed between the anode plate and the cathode plate at least at a raised region of the bipolar plate. Background Art

[0003] A fuel cell system for powering a propulsion system for a vehicle (e.g., a passenger car or commercial vehicle) typically includes a fuel cell stack having a plurality of fuel cells connected in series by stacking the fuel cells on top of each other. Typically, each cell includes a membrane electrode assembly sandwiched between a pair of bipolar plates. The bipolar plates of adjacent cells are bonded to each other to provide a conductive connection between the cells, increase the physical strength of the fuel cell stack, and can seal a flow field extending through the bipolar plates and / or membrane electrode assembly. Forces experienced by the bipolar plates (e.g., to create a seal between adjacent bipolar plates) or excessive forces experienced during a vehicle collision or due to vibration or stress during vehicle operation can cause excessive compression or buckling of the bipolar plates and result in loss of electrical connection between the cells and leakage of the flow field.

[0004] To improve the structural integrity and sealing of a fuel cell stack, a bipolar plate comprising an anode plate and a cathode plate includes a reinforcement layer between the anode plate and the cathode plate, at least in a raised region of the bipolar plate. The raised region of the bipolar plate includes a cavity between the respective inner sides of the anode plate and the cathode plate, and corresponding gaskets on the outer sides of the anode plate and the cathode plate. When the bipolar plate is positioned within a fuel cell stack of a fuel cell system, the gaskets engage corresponding structures of the fuel cell stack. The reinforcement layer is coupled to the inner sides of the anode plate and the cathode plate and extends within the cavity to reduce the effects of compressive forces on the structural integrity of the raised region of the bipolar plate. Summary of the Invention

[0005] One aspect of the present disclosure provides a bipolar plate. The bipolar plate includes an anode plate and a cathode plate. The anode plate has an inner side and an outer side opposite the inner side. The cathode plate has an inner side and an outer side opposite the inner side. The inner side of the cathode plate faces the inner side of the anode plate. The bipolar plate includes a raised area. The portion of the inner side of the anode plate at the raised area is spaced apart from the portion of the inner side of the cathode plate at the raised area. The bipolar plate includes a reinforcement layer disposed between the inner side of the anode plate and the inner side of the cathode plate at the raised area. The reinforcement layer is configured to resist compressive forces experienced at the outer sides of the anode plate and the cathode plate at the raised area.

[0006] Embodiments of the present disclosure may include one or more of the following optional features. In some embodiments, the bipolar plate further comprises a first gasket and a second gasket. The first gasket is disposed at the outer side of the anode plate at the raised area. The second gasket is disposed at the outer side of the cathode plate at the raised area. The first gasket and the second gasket are configured to engage corresponding membrane electrode assemblies of a fuel cell stack of a fuel cell system when the bipolar plate is disposed in the fuel cell stack. In a further embodiment, the first gasket and the second gasket are configured to seal corresponding flow fields extending across the outer sides of the anode plate and the cathode plate when engaging corresponding membrane electrode assemblies of the fuel cell stack.

[0007] In some examples, the bipolar plate further comprises a cavity defined between a portion of the inner side of the anode plate at the raised area and a portion of the inner side of the cathode plate at the raised area. The reinforcement layer extends within the cavity at the raised area. In other examples, the reinforcement layer comprises a hole that fluidly connects a first portion of the cavity between the inner side of the anode plate and the reinforcement layer and a second portion of the cavity between the inner side of the cathode plate and the reinforcement layer.

[0008] In some aspects, the reinforcement layer includes a spline disposed between portions of the inner side of the anode plate and portions of the inner side of the cathode plate at the raised area and not disposed between other portions of the inner side of the anode plate and other portions of the inner side of the cathode plate away from the raised area.

[0009] In some embodiments, the reinforcement layer includes an intermediate plate disposed between portions of the inner side of the anode plate and the inner side of the cathode plate at the raised area, and between other portions of the inner side of the anode plate and the inner side of the cathode plate away from the raised area.

[0010] In some examples, one of the anode plate and the cathode plate includes a carrier portion recessed from an inner side of the corresponding one of the anode plate and the cathode plate. The reinforcement layer is accommodated in the carrier portion.

[0011] In some aspects, the reinforcement layer is non-planar.In some embodiments, the reinforcement layer is laser welded to the anode and cathode plates.

[0012] Another aspect of the present disclosure provides a fuel cell system. The fuel cell system includes a fuel cell stack. The fuel cell stack includes a plurality of fuel cells. At least one fuel cell in the plurality of fuel cells includes a membrane electrode assembly sandwiched between a pair of bipolar plates. Each bipolar plate in the pair of bipolar plates includes an anode plate and a cathode plate. The anode plate has an inner side and an outer side opposite the inner side. The cathode plate has an inner side and an outer side opposite the inner side. The inner side of the cathode plate faces the inner side of the anode plate. Each bipolar plate includes a raised area. The portion of the inner side of the anode plate at the raised area is spaced apart from the portion of the inner side of the cathode plate at the raised area. Each bipolar plate includes a reinforcement layer disposed between the inner side of the anode plate and the inner side of the cathode plate at the raised area. The reinforcement layer is configured to resist compressive forces experienced at the outer side of the anode plate and the outer side of the cathode plate at the raised area. This aspect may include one or more of the following optional features.

[0013] In some embodiments, each bipolar plate in the pair further includes a first gasket and a second gasket. The first gasket is disposed on an outer side of the anode plate at the raised area. The second gasket is disposed on an outer side of the cathode plate at the raised area. The first gasket and the second gasket engage corresponding membrane electrode assemblies of the fuel cell stack.

[0014] In some examples, the fuel cell system further includes a cavity defined between a portion of the inner side of the anode plate at the raised area and a portion of the inner side of the cathode plate at the raised area. The reinforcement layer extends within the cavity at the raised area.

[0015] In some aspects, the reinforcement layer includes a plug that is disposed between portions of the inner side of the anode plate and the inner side of the cathode plate at the raised area and is not disposed between other portions of the inner side of the anode plate and the inner side of the cathode plate away from the raised area.

[0016] In some embodiments, the reinforcement layer includes an intermediate plate disposed between a portion of the inner side of the anode plate and a portion of the inner side of the cathode plate at the raised area, and between other portions of the inner side of the anode plate and other portions of the inner side of the cathode plate away from the raised area.

[0017] Another aspect of the present disclosure provides a vehicle. The vehicle includes a fuel cell system having a fuel cell stack. The fuel cell stack includes a plurality of fuel cells. At least one of the plurality of fuel cells includes a membrane electrode assembly sandwiched between a pair of bipolar plates. Each bipolar plate in the pair of bipolar plates includes an anode plate and a cathode plate. The anode plate has an inner side and an outer side opposite the inner side. The cathode plate has an inner side and an outer side opposite the inner side. The inner side of the cathode plate faces the inner side of the anode plate. Each bipolar plate includes a raised area. The portion of the inner side of the anode plate at the raised area is spaced apart from the portion of the inner side of the cathode plate at the raised area. Each bipolar plate includes a reinforcement layer disposed between the inner side of the anode plate and the inner side of the cathode plate at the raised area. The reinforcement layer is configured to resist compressive forces experienced on the outer sides of the anode plate and the cathode plate at the raised area. This aspect may include one or more of the following optional features.

[0018] In some embodiments, each bipolar plate in the pair further includes a first gasket and a second gasket. The first gasket is disposed outside the anode plate at the raised area. The second gasket is disposed outside the cathode plate at the raised area. The first gasket and the second gasket engage corresponding membrane electrode assemblies of the fuel cell stack.

[0019] In some examples, the vehicle further includes a cavity defined between a portion of the inner side of the anode plate at the raised area and a portion of the inner side of the cathode plate at the raised area. The reinforcement layer extends within the cavity at the raised area.

[0020] In some aspects, the reinforcement layer includes a plug that is disposed between portions of the inner side of the anode plate and the inner side of the cathode plate at the raised area and is not disposed between other portions of the inner side of the anode plate and the inner side of the cathode plate away from the raised area.

[0021] In some embodiments, the reinforcement layer includes an intermediate plate disposed between portions of the inner side of the anode plate and the inner side of the cathode plate at the raised area, and between other portions of the inner side of the anode plate and the inner side of the cathode plate away from the raised area.

[0022] The details of one or more embodiments of the present disclosure are set forth in the accompanying drawings and the description below. Other aspects, features, and advantages will be apparent from the description and the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are for illustrative purposes only of selected configurations and are not intended to limit the scope of the present disclosure.

[0024] Figure 1 It is an exploded view of a fuel cell stack of a fuel cell system.

[0025] Figure 2 It is a plan view of the bipolar plate of the fuel cell system.

[0026] Figure 3 It is a plan view of the reinforcement layer of the bipolar plate.

[0027] Figures 4A-4E It is along Figure 2 4-4 is a cross-sectional view of an exemplary configuration of a raised region of a bipolar plate.

[0028] Figure 5A yes Figure 2 FIG. 5 is an enlarged view of the raised area of ​​the bipolar plate at region 5A.

[0029] Figures 5B-5D are cross-sectional views of exemplary configurations of raised regions of a bipolar plate and corresponding pressure gradients along the curvature of the corresponding raised regions under compression.

[0030] Figure 5E It shows Figures 5B-5D Plot of the displacement of the bulge area under compressive load.

[0031] Corresponding reference characters indicate corresponding parts throughout the several views of the drawings. DETAILED DESCRIPTION

[0032] Example configurations will now be described more fully with reference to the accompanying drawings. The example configurations are provided so that this disclosure will be thorough and will fully convey the scope of the disclosure to those of ordinary skill in the art. Specific details, such as examples of specific components, devices, and methods, are set forth to provide a thorough understanding of the configurations of the present disclosure. It will be apparent to those of ordinary skill in the art that specific details need not be employed, that the example configurations may be embodied in many different forms, and that the specific details and example configurations should not be construed as limiting the scope of the present disclosure.

[0033] The terms used herein are only used to describe the purpose of specific exemplary configurations and are not intended to be limiting. As used herein, the singular articles "a", "an" and "the" may also be intended to include plural forms, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "including" and "having" are inclusive and therefore specify the presence of features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts and / or groups thereof. The method steps, processes and operations described herein should not be interpreted as necessarily requiring them to be performed in the specific order discussed or shown, unless specifically identified as an execution order. Additional or alternative steps may be adopted.

[0034] When an element or layer is referred to as being "on," "engaged to," "connected to," "attached to," or "coupled to" another element or layer, it may be directly on, directly engaged, connected, attached to, or coupled to the other element or layer, or there may be intervening elements or layers. Conversely, when an element is referred to as being "directly on," "directly engaged to," "directly connected to," "directly attached to," or "directly coupled to" another element or layer, there may be no intervening elements or layers. Other words used to describe the relationship between elements should be interpreted in a similar manner (e.g., "between" versus "directly between," "adjacent" versus "directly adjacent," etc.). As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0035] The terms "first", "second", "third" etc. may be used in this article to describe various elements, components, regions, layers and / or parts. These elements, components, regions, layers and / or parts should not be limited by these terms. These terms can only be used to distinguish one element, component, region, layer or part from another region, layer or part. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply an order or sequence. Therefore, without departing from the teachings of the example configurations, the first element, component, region, layer or part discussed below may be referred to as a second element, component, region, layer or part.

[0036] In this application, including the definitions below, the term "module" may be replaced with the term "circuit". The term "module" may refer to, be part of, or include: an application-specific integrated circuit (ASIC); a digital, analog, or mixed analog / digital discrete circuit; a digital, analog, or mixed analog / digital integrated circuit; a combinational logic circuit; a field-programmable gate array (FPGA); a processor (shared, dedicated, or group) that executes code; a memory (shared, dedicated, or group) that stores code executed by the processor; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system on a chip.

[0037] The term "code" as used above may include software, firmware and / or microcode, and may refer to programs, routines, functions, classes and / or objects. The term "shared processor" includes a single processor that executes some or all code from multiple modules. The term "group processor" includes a processor that, in combination with additional processors, executes some or all code from one or more modules. The term "shared memory" encompasses a single memory that stores some or all code from multiple modules. The term "group memory" includes memory that, in combination with additional memory, stores some or all code from one or more modules. The term "memory" may be a subset of the term "computer-readable medium". The term "computer-readable medium" does not include transient electrical and electromagnetic signals propagated through the medium, and therefore may be considered to be both tangible and non-transitory memory. Non-limiting examples of non-transitory memory include tangible computer-readable media, including non-volatile memory, magnetic memory, and optical memory.

[0038] The apparatus and methods described herein may be implemented in part or in whole by one or more computer programs executed by one or more processors. The computer programs include processor-executable instructions stored on at least one non-transitory tangible computer-readable medium. The computer programs may also include and / or rely on stored data.

[0039] A software application (i.e., a software resource) may refer to computer software that enables a computing device to perform tasks. In some examples, a software application may be referred to as an "application," "app," or "program." Example applications include, but are not limited to, system diagnostic applications, system management applications, system maintenance applications, word processing applications, spreadsheet applications, messaging applications, media streaming applications, social networking applications, and gaming applications.

[0040] Non-transitory memory can be a physical device used to temporarily or permanently store programs (e.g., sequences of instructions) or data (e.g., program state information) for use by a computing device. Non-transitory memory can be volatile and / or non-volatile addressable semiconductor memory. Examples of non-volatile memory include, but are not limited to, flash memory and read-only memory (ROM) / programmable read-only memory (PROM) / erasable programmable read-only memory (EPROM) / electrically erasable programmable read-only memory (EEPROM) (e.g., commonly used for firmware, such as bootloaders). Examples of volatile memory include, but are not limited to, random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), phase change memory (PCM), and disk or tape.

[0041] These computer programs (also referred to as programs, software, software applications, or code) include machine instructions for a programmable processor and may be implemented in high-level procedural and / or object-oriented programming languages ​​and / or assembly / machine languages. As used herein, the terms "machine-readable medium" and "computer-readable medium" refer to any computer program product, non-transitory computer-readable medium, apparatus, and / or device (e.g., a disk, optical disk, memory, programmable logic device (PLD)) for providing machine instructions and / or data to a programmable processor, including machine-readable media that receives machine instructions as a machine-readable signal. The term "machine-readable signal" refers to any signal used to provide machine instructions and / or data to a programmable processor.

[0042] Various implementations of the systems and techniques described herein can be implemented in digital electronic and / or optical circuitry, integrated circuits, specially designed ASICs (application-specific integrated circuits), computer hardware, firmware, software, and / or combinations thereof. These various implementations can include implementation in one or more computer programs executable and / or interpretable on a programmable system comprising at least one programmable processor, which can be special purpose or general purpose, coupled to receive data and instructions from and send data and instructions to a storage system, at least one input device, and at least one output device.

[0043] The processes and logic flows described in this specification can be performed by one or more programmable processors (also referred to as data processing hardware) that execute one or more computer programs to perform functions by operating on input data and generating outputs. The processes and logic flows can also be performed by dedicated logic circuits (e.g., FPGAs (field programmable gate arrays) or ASICs (application-specific integrated circuits)). As an example, processors suitable for executing computer programs include both general-purpose and special-purpose microprocessors, as well as any one or more processors of any type of digital computer. Typically, a processor will receive instructions and data from a read-only memory or a random access memory or both. The basic elements of a computer are a processor for executing instructions and one or more memory devices for storing instructions and data. Typically, a computer will also include one or more mass storage devices (e.g., magnetic disks, magneto-optical disks, or optical disks) for storing data, or be operably coupled to receive data from or transmit data to or to the one or more mass storage devices. However, a computer need not have such devices. Computer-readable media suitable for storing computer program instructions and data include all forms of nonvolatile memory, media, and storage devices, including, for example, semiconductor memory devices such as EPROM, EEPROM, and flash memory devices; magnetic disks, such as internal hard disks or removable disks; magneto-optical disks; and CD ROM and DVD-ROM disks. The processor and memory can be supplemented by, or incorporated in, special purpose logic circuitry.

[0044] To provide for interaction with a user, one or more aspects of the present disclosure may be implemented on a computer having a display device (e.g., a CRT (cathode ray tube), an LCD (liquid crystal display) monitor, or a touch screen) for displaying information to the user and, optionally, a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the computer. Other kinds of devices may also be used to provide for interaction with the user; for example, the feedback provided to the user may be any form of sensory feedback, such as visual feedback, auditory feedback, or tactile feedback; and input from the user may be received in any form, including sound, voice, or tactile input. Additionally, a computer may interact with a user by sending documents to and receiving documents from a device used by the user; for example, by sending a web page to a web browser on a user's client device in response to a request received from the web browser.

[0045] Referring now to the drawings and the illustrated configurations depicted therein, a fuel cell system 100 for powering a propulsion system of a vehicle (e.g., a passenger car, a mass transit vehicle, a commercial vehicle, etc.) includes a plurality of power generation cells or fuel cells 104 ( Figure 1) fuel cell stack 102. Each fuel cell 104 may include a membrane electrode assembly (MEA) 106 or a unitized electrode assembly (UEA) sandwiched between a pair of bipolar plates (BPPs) 200. For example, the MEA 106 may include a membrane 108 (e.g., including an anode layer and a cathode layer on opposite sides of the membrane 108) that houses a catalyst 110. The BPPs 200 provide structural support to the fuel cell stack 102 and electrically connect the fuel cells 104 in series so that the electricity generated at the MEAs 106 of the fuel cell stack 102 produces a usable output voltage.

[0046] Each BPP 200 includes an anode plate or panel 202 and a cathode plate or panel 204 ( Figures 4A-4E ). The anode plate 202 and the cathode plate 204 can be formed of a metal material, carbon or a composite material. For example, the anode plate 202 and the cathode plate 204 can be formed of a steel plate having a thickness of 85 microns or less, stainless steel (e.g., 304 stainless steel, 316 stainless steel or ferritic stainless steel), electroplated steel, aluminum, titanium or a surface-treated metal plate. The anode plate 202 and the cathode plate 204 are stamped to form and connected together, for example by welding (e.g., laser welding), brazing or pressing at the periphery of the plate. When disposed in the fuel cell stack 102, the anode plate 202 and the cathode plate 204 can be arranged in an alternating pattern so that the anode plate 202 engages one side of the MEA 106 and the cathode plate 204 engages the opposite side of the MEA 106 to guide electricity through the fuel cell stack 102 in a given direction.

[0047] like Figure 1 and Figure 2 As shown, corresponding openings or channels 206 are formed through the BPP 200 and are aligned with corresponding openings or channels 112 formed through the MEA 106 to define pathways along the fuel cell stack 102 that allow fluid communication between the fuel cells 104. For example, corresponding channels extending between the BPP 200 and the MEA 106 of the fuel cell stack 102 can carry oxygen-containing gas, hydrogen fuel gas, and coolant to flow between the fuel cells 104 of the fuel cell stack 102. Each BPP 200 defines a flow field 208 across the outer surface of the BPP 200 to allow fluid to flow between the BPP 200 and the MEA 106, wherein the flow field 208 can include a series of channels or valleys and protrusions that direct flow through the BPP 200 and between two or more openings 206 (i.e., an inlet opening and an outlet opening). For example, the fuel cell system 100 may include the fuel cell systems and fuel cells described in US Patents 10,211,473, 10,411,272, 10,522,847, and / or 10,529,996, which are incorporated herein by reference in their entirety.

[0048] As further described below, the BPP 200 includes one or more ridges or raised areas 210, 210a-e that are raised relative to the flow field 208 and engage corresponding structures within the fuel cell stack 102 to separate a portion of the BPP 200 from the MEA 106 to allow fluid communication therebetween and to seal a portion of the flow field 208 and accommodate fluid flow along a desired path. For example, the ridges 210 may be formed around a peripheral area of ​​the BPP 200 and configured to engage a side of the MEA 106 and / or another BPP 200 to seal an outer edge of the flow field 208. Additionally, the ridges 210 may be formed at least partially around the opening 206 and configured to engage a side of the MEA 106 to fluidically isolate or allow fluid communication between the opening 206 and the flow field 208. That is, the ridge 210 can surround the opening 206 to fluidically isolate the opening 206 from the flow field 208, or the ridge 210 can partially surround the opening 206 to allow fluid to flow between the opening 206 and the flow field 208, so that the fluid flowing through the opening 206 can be delivered only to a designated portion of the fuel cell stack 102. For example, one or more channels or tubes 212 can extend through the ridge area 210 between the opening 206 and the flow field 208 to fluidically connect the opening 206 and the flow field 208. Thus, the ridge 210 separates the BPP 200 from the MEA 106 to allow at least one of oxygen, hydrogen, and coolant to flow through the flow field surface 208 of the BPP 200 between the inlet opening 206 and the outlet opening 206. The structural integrity of the ridge 210 is critical to preventing leaks and maintaining electrical connections across the fuel cell 104.

[0049] like Figures 4A-4E As shown, each protrusion 210 is formed by a protrusion of the anode plate 202 or cathode plate 204 that engages an adjacent structure of the fuel cell stack 102 (e.g., the MEA 106 or another BPP 200). In the example shown, both the anode plate 202 and the cathode plate 204 include corresponding protrusions to provide uniform spacing between the BPP 200 and the MEA 106 and to provide a more direct path for compressive forces at the fuel cell stack 102. Because the anode plate 202 and the cathode plate 204 are formed from metal sheets having a uniform thickness, the corresponding protrusions are stamped into the plates and result in the formation of a chamber or cavity 214 between the anode plate 202 and the cathode plate 204. The cavity 214 can facilitate fluid flow between the opening 206 and the flow field 208.

[0050] Thus, the anode plate 202 has an inner side 216 and an outer side 218 opposite the inner side 216, and the cathode plate 204 has an inner side 220 and an outer side 222 opposite the inner side 220. The inner side 216 of the anode plate 202 faces the inner side 220 of the cathode plate 204, and the inner side 216 of the anode plate 202 is spaced apart from the inner side 220 of the cathode plate 204 at the raised area 210 of the BPP 200 to define the cavity 214 and to elevate the raised area 210 relative to the flow field 208. A portion of the anode plate 202 can be coupled to a portion of the cathode plate 204 away from the raised area 210, such as via a laser fusion weld joint 224, to join the anode and cathode plates 202, 204 and fluidically seal the cavity 214.

[0051] A first gasket 226 is disposed at the outer side 218 of the anode plate 202 at the raised area 210, and a second gasket 228 is disposed at the outer side 222 of the cathode plate 204 at the raised area 210, such that, with the BPP 200 disposed within the fuel cell stack 102, the first gasket 226 and the second gasket 228 engage corresponding structures of the fuel cell stack 102 and seal the corresponding flow field 208 extending through the outer side 218 of the anode plate 202 and the outer side 222 of the cathode plate 204. For example, the gaskets may engage one or more of the MEA 106, another BPP 200, an end plate of the fuel cell stack 102, etc. The first gasket 226 and the second gasket 228 may be formed of a rubberized polymer or any suitable material configured to compress and / or flex to seal between adjacent surfaces.

[0052] To reduce compression of the ridged area 210 and lateral movement of the anode plate 202 and cathode plate 204 relative to each other when subjected to compressive forces at the BPP 200, a reinforcement layer 300 is disposed between the inner side 216 of the anode plate 202 and the inner side 220 of the cathode plate 204 at least at the ridged area 210. For example, when assembling the fuel cell stack 102, compressive forces may be applied along the fuel cell stack 102 to maintain electrical connections between the fuel cells 104 and to enable sealing at the ridged area 210 along the sealing path defined by the gasket. During vehicle operation and / or in the event of a vehicle crash, additional forces may act on the ridged area 210. Excessive compression or buckling of the ridged area 210 may result in leakage in the flow field 208 and / or electrical disconnection between the fuel cells 104. The reinforcement layer 300 reinforces the ridged area 210 to resist buckling loads and provides uniform pressure distribution across the seal in the ridged area 210, thereby reducing or eliminating plate buckling.

[0053] like Figure 3As shown, the reinforcement layer 300 may include a stamped plate or panel 302 disposed between the anode plate 202 and the cathode plate 204. The reinforcement layer 300 may be formed of the same material as the anode plate 202 and the cathode plate 204, or the reinforcement layer 300 may be formed of a different material, such as a thinner metal (e.g., having a thickness of 75 microns or less or 65 microns or less) and / or a softer metal (e.g., titanium, aluminum, stainless steel, etc.). In the example shown, the reinforcement plate 302 includes corresponding openings 304 configured to align with the openings 112 of the MEA 106 and the openings 206 of the BPP 200, as well as voids or holes 306 configured to align with the flow field 208. Thus, the reinforcement plate 302 is disposed between the inner side 216 of the anode plate 202 and the inner side 220 of the cathode plate 204 at the raised area 210 and at other portions of the BPP 200 away from the raised area 210.

[0054] refer to Figure 4A , a first example of a raised region 210, 210a includes a reinforcement plate 302 that spans and / or extends within the cavity 214 between the anode plate 202 and the cathode plate 204. Respective laser weld joints 224 can be formed along opposing sides of the cavity 214 to join the anode plate 202, the cathode plate 204, and the reinforcement layer 300. In the example shown, the raised region 210a is symmetrical such that the reinforcement plate 302 is substantially planar, and the inner side 216, 220 of the anode plate 202 and the cathode plate 204 are equidistantly spaced from the reinforcement layer 300.

[0055] like Figure 4B As shown, a second example of the raised areas 210, 210b has a reinforcement layer 300 provided as a reinforcement plug or insert 308. The plug 308 is disposed between the anode plate 202 and the cathode plate 204 only at or near the raised area 210b to reduce the thickness of the BPP 200 away from the raised area 210. In other words, the plug 308 is disposed between the inner side 216 of the anode plate 202 and the inner side 220 of the cathode plate 204 at the raised area 210b, and the plug 308 is not disposed between the inner side 216 of the anode plate 202 and the inner side 220 of the cathode plate 204 away from the raised area 210b. The cathode plate 204 includes a recessed portion or carrier portion 230 recessed from the inner side 220 of the cathode plate 204 to accommodate a peripheral edge portion of the plug 308 so that the planar plug 308 can extend substantially parallel to the plane of the cathode plate 204. In some examples, the anode plate 202 may alternatively or additionally include a recessed portion for at least partially accommodating an edge portion of the plug 308. The laser fusion joint 224 may directly couple the anode plate 202 and the cathode plate 204 away from the raised region 210b, while the laser fusion joint 224 couples the anode plate 202, the cathode plate 204, and the plug 308 within the raised region 210b.

[0056] In a third example of raised areas 210, 210c, and such as Figure 4C As shown, at least a portion of the reinforcement layer 300 is non-planar. In other words, the reinforcement layer 300 can be bent, curved, or offset toward one of the anode plate 202 and the cathode plate 204 to provide an asymmetric raised region 210c. The asymmetric or offset reinforcement layer 300 can provide customized pressure distribution and stiffness across the raised region 210c.

[0057] refer to Figure 4D , a fourth example of a raised region 210, 210d has one or more perforations or vents 310 formed through the reinforcement layer 300. The perforations 310 reduce the stiffness of the raised region 210d and allow fluid communication between the portion of the cavity 214 between the anode plate 202 and the reinforcement layer 300 and the portion of the cavity 214 between the cathode plate 204 and the reinforcement layer 300.

[0058] like Figure 4E As shown, the fifth example of the raised regions 210, 210e shows a reinforcement layer 300 coupled to the anode plate 202 and the cathode plate 204 via a laser fusion weld joint 224 at one end and extending along the channel 212 of the BPP 200 at the other end. That is, portions of the reinforcement layer 300 may be spaced apart from the inner side 216 of the anode plate 202 and / or the inner side 220 of the cathode plate 204, such as along the channel 212, to allow fluid communication from the cavity 214 and between the reinforcement layer 300 and the anode plate 202 and / or cathode plate 204.

[0059] The ridges 210 may be adjusted or tuned (such as by adjusting the geometry and shape of the reinforcement layer 300) to achieve desired sealing pressures and ridge stiffness at different areas of the BPP 200. For example, portions of the ridges 210 may be symmetrical (e.g., Figure 4A ) to provide uniform sealing pressure at the first gasket 226 and the second gasket 228 and a high buckling load against compression at the ridge 210. In addition, the reinforcement layer 300 may be curved (e.g., Figure 4C ) and / or include perforations 310 (e.g., Figure 4D ) to reduce the bump stiffness, such as at the corner areas of the bump 210. The reinforcement layer 300 may be disposed between the anode plate 202 and the cathode plate 204 across the entire bump sealing path (e.g., the reinforcement sheet 302), or the reinforcement layer 300 may alternatively be placed across only a portion of the bump sealing path (e.g., the reinforcement plug 308).

[0060] refer to Figures 5A-5E, graph 500 depicts exemplary displacements of BPPs under compressive loads with different configurations of ridge regions. That is, graph 500 illustrates ridges without a reinforcement layer ( Figure 5B ), when set in the fuel cell stack when the single-sided bulge ( Figure 5C ) and the raised area 210 ( Figure 5D As shown, the raised areas 210 with the reinforcement layer 300 provide excellent structural integrity to the fuel cell stack, resisting displacement or compression even under higher compressive loads.

[0061] also, Figures 5B-5D The compression graphs 502, 502B-D represent the compression graphs along Figure 5A As shown, the raised area 210 with the reinforcement layer provides uniform pressure distribution at the first gasket 226 and the second gasket 228 along the straight and curved portions of the raised seal.

[0062] Thus, the BPP 200 of the fuel cell system 100 includes a reinforcement layer 300 disposed between the anode plate 202 and the cathode plate 204 of the BPP 200, at least at the ridge region 210 of the BPP 200. The reinforcement layer 300 provides high resistance to buckling loads at the BPP 200, thereby reducing compression or buckling of the ridge region 210 and providing a more uniform seal between the BPP 200 and adjacent structures within the fuel cell stack 102 (e.g., adjacent BPPs 200 and / or MEAs 106). The reinforcement layer 300 can be adjusted to adjust the stiffness at different portions of the ridge region 210 and to allow or prevent fluid communication between different portions of the interior cavity 214 of the ridge 210. Furthermore, the addition of the reinforcement layer 300 allows the anode plate 202 and cathode plate 204 to be made of thinner and / or softer metal sheets, thereby reducing the weight of the fuel cell stack 102 without sacrificing structural integrity.

[0063] A number of embodiments have been described. However, it will be appreciated that various modifications can be made without departing from the spirit and scope of this disclosure. Accordingly, other embodiments are within the scope of the following claims.

[0064] The foregoing description is provided for the purpose of illustration and description. It is not intended to be exhaustive or to limit the present disclosure. Individual elements or features of a particular configuration are generally not limited to that particular configuration, but are interchangeable where applicable and can be used in a selected configuration, even if not specifically shown or described. They may also vary in many ways. Such variations should not be considered as departing from the present disclosure, and all such modifications are intended to be included within the scope of the present disclosure.

Claims

1. A bipolar plate comprising: an anode plate having an inner side and an outer side opposite the inner side; a cathode plate having an inner side and an outer side opposite to the inner side, the inner side of the cathode plate facing the inner side of the anode plate; a raised area, wherein a portion of the inner side of the anode plate at the raised area is spaced apart from a portion of the inner side of the cathode plate at the raised area; as well as A reinforcement layer is disposed between inner sides of the anode plate and the cathode plate at the raised area, the reinforcement layer being configured to resist compressive forces experienced at outer sides of the anode plate and the cathode plate at the raised area.

2. The bipolar plate according to claim 1, further comprising: a first gasket disposed on an outer side of the anode plate at the raised area; as well as A second gasket is disposed at an outer side of the cathode plate at the raised area, the first and second gaskets being configured to engage corresponding membrane electrode assemblies of a fuel cell stack of a fuel cell system when the bipolar plate is disposed in a fuel cell stack.

3. The bipolar plate according to claim 2, wherein: The first gasket and the second gasket are configured to seal respective flow fields extending across outsides of the anode plate and the cathode plate when engaged with respective membrane electrode assemblies of the fuel cell stack.

4. The bipolar plate of claim 1 , further comprising a cavity defined between a portion of an inner side of the anode plate at the raised area and a portion of an inner side of the cathode plate at the raised area, the reinforcement layer extending within the cavity at the raised area.

5. The bipolar plate of claim 4, wherein the reinforcement layer includes a hole that fluidly connects a first portion of the cavity between the inner side of the anode plate and the reinforcement layer and a second portion of the cavity between the inner side of the cathode plate and the reinforcement layer.

6. The bipolar plate according to claim 1, wherein: The reinforcement layer includes a plug, which is arranged between the portion of the inner side of the anode plate and the portion of the inner side of the cathode plate at the raised area, and is not arranged between other portions of the inner side of the anode plate and the other portions of the inner side of the cathode plate away from the raised area.

7. The bipolar plate according to claim 1, wherein: The reinforcement layer includes an intermediate plate, which is arranged between the portion of the inner side of the anode plate and the portion of the inner side of the cathode plate at the raised area, and between other portions of the inner side of the anode plate and the other portions of the inner side of the cathode plate away from the raised area.

8. The bipolar plate according to claim 1, wherein: One of the anode plate and the cathode plate includes a carrier portion recessed from an inner side of the corresponding one of the anode plate and the cathode plate, and the reinforcement layer is accommodated in the carrier portion.

9. The bipolar plate of claim 1, wherein the reinforcement layer is non-planar.

10. The bipolar plate of claim 1, wherein the reinforcement layer is laser welded to the anode plate and the cathode plate.

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