A stack end plate and a fuel cell stack

Abstract

This invention discloses a fuel cell stack end plate and a fuel cell stack. The end plate includes an outer shell and a nested body. The outer shell has a first manifold receiving groove and a second manifold receiving groove, both penetrating the outer shell through its thickness. The nested body includes an insulating plate, a first manifold assembly, and a second manifold assembly. The first and second manifold assemblies are nested into the first and second manifold receiving grooves respectively and connected to the insulating plate. The insulating plate is located on the back of the outer shell. This invention can improve the problem of low voltage in the end cells of a fuel cell stack.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to a fuel cell stack end plate and a fuel cell stack. Background Technology

[0002] A fuel cell is an energy conversion device that generates electricity through an electrochemical reaction between hydrogen and oxygen. Its reaction product is only water, achieving true pollution-free and zero-emission requirements.

[0003] A fuel cell stack consists of multiple cells connected in series. If the voltage of any one cell is too low, it will affect the overall performance of the fuel cell stack. The performance of each individual cell has a significant impact on the overall stability of the fuel cell stack and the decrease in cell consistency. During the operation of the fuel cell stack, the performance of the lowest-performing cell will continue to decline, and even show significant reverse polarity durability loss. Therefore, the overall lifespan of the fuel cell stack is determined by the lowest-performing cell. In short, the performance of a fuel cell stack is limited by the worst-performing individual cell in the entire stack.

[0004] Existing fuel cell stack endplate designs generally consider factors such as mechanical strength, waterproofing, dustproofing, and insulation. Mechanical strength design primarily addresses the issue of uneven pressure distribution caused by significant deformation of the stack under sealing force, leading to uneven voltage distribution and potential water blockage. Therefore, the design assumes a relatively constant pressure transmission along the fuel cell stack surface. However, this design fails to adequately consider the impact of the endplate manifold on the uniformity of gas distribution within the stack core and its influence on the air intake of individual cells located at the stack ends (referred to as end cells). This design flaw may result in lower air intake for end cells compared to those in the middle of the stack, leading to lower voltage in end cells and affecting the overall stack voltage consistency. In severe cases, this could pose a risk of stack burnout. Summary of the Invention

[0005] The purpose of this invention is to provide a fuel cell stack end plate and a fuel cell stack to improve the problem of low voltage of individual cells at the end of the fuel cell stack.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0007] An electric stack end plate includes: a housing body 1 and a nesting body; the housing body 1 includes a front side and a back side opposite to the front side, and the housing body 1 is provided with a first manifold receiving groove 20 and a second manifold receiving groove 21; the first manifold receiving groove 20 and the second manifold receiving groove 21 penetrate the housing body 1 in the thickness direction; the nesting body includes: an insulating plate 22, a first manifold assembly 2a and a second manifold assembly 2b; the first manifold assembly 2a and the second manifold assembly 2b are respectively nested into the first manifold receiving groove 20 and the second manifold receiving groove 21, and are connected to the insulating plate 22; the insulating plate 22 is located on the back side of the housing body 1.

[0008] Optionally, it also includes: a reinforcing rib 3, which is disposed on the front side of the outer shell body 1.

[0009] Optionally, a plurality of mounting holes 4 are provided on the edge of the outer casing 1, and the plurality of mounting holes 4 are provided at intervals along the circumference of the outer casing 1.

[0010] Optionally, the back of the outer casing 1 is provided with a receiving groove that matches the insulating plate 22. After the insulating plate 22 is placed in the receiving groove, the back of the outer casing 1 is a flat surface.

[0011] Optionally, the first manifold assembly 2a includes: a hydrogen inlet manifold 7, a coolant inlet manifold 6, and an air outlet manifold 5; the diameter D7 of the hydrogen inlet manifold 7 gradually increases from the front to the back; the diameter D6 of the coolant inlet manifold 6 gradually increases from the front to the back; and the diameter D5 of the air outlet manifold 5 gradually decreases from the front to the back.

[0012] Optionally, the second manifold assembly 2b includes: a hydrogen outlet manifold 8, a coolant outlet manifold 9, and an air inlet manifold 10; the diameter D10 of the air inlet manifold 10 gradually increases from the front to the back; the diameter D9 of the coolant outlet manifold 9 gradually decreases from the front to the back; and the diameter D8 of the hydrogen outlet manifold 8 gradually decreases from the front to the back.

[0013] Optionally, the maximum value of the diameter D7 of the hydrogen inlet manifold 7 is less than the minimum value of the diameter D6 of the coolant inlet manifold 6, and the maximum value of the diameter D6 of the coolant inlet manifold 6 is less than the minimum value of the diameter D5 of the air outlet manifold 5.

[0014] Optionally, hydrogen enters the fuel cell stack core through the hydrogen inlet manifold 7 and then exits through the hydrogen outlet manifold 8; coolant enters the fuel cell stack core through the coolant inlet manifold 6 and then exits through the coolant outlet manifold 9; air enters the fuel cell stack core through the air inlet manifold 10 and then exits through the air outlet manifold 5.

[0015] Optionally, the hydrogen inlet manifold 7, the coolant inlet manifold 6, and the air outlet manifold 5 are integrated; the hydrogen outlet manifold 8, the coolant outlet manifold 9, and the air inlet manifold 10 are integrated.

[0016] On the other hand, the present invention also provides a fuel cell stack, comprising: a stack end plate as described above, a stack housing 14, and a stack core 12 disposed inside the stack housing 14; the end of the stack housing 14 is provided with a blind hole matching the mounting hole 4 on the stack end plate, and a bolt 15 is passed through the mounting hole 4 and stops in the blind hole to fix the stack end plate on the end of the stack housing 14; a sealing ring 11 is provided between the stack end plate and the stack housing 14.

[0017] This invention has at least one of the following advantages:

[0018] The fuel cell stack end plate provided by this invention is positioned close to the end cells. This invention features a nested end plate design, comprising nested outer shells, nested main bodies, or nested injection-molded insulating portions. Therefore, the fuel cell stack end plate of this invention not only integrates an insulating plate to provide good insulation performance and, to a certain extent, uniform pressure, but also improves the air intake of the end cells, thereby enhancing the performance of the end cells and improving the overall voltage consistency of the fuel cell stack. Furthermore, the nested structure effectively reduces the risk of air leakage between the end plate and the insulating plate.

[0019] This invention improves the uniformity of fluid distribution within the manifold by setting endplate manifold inlets and outlets of different diameters. It does not introduce additional fluid distribution devices, resulting in a simple structure and ease of implementation. Specifically, the first manifold assembly 2a and the second manifold assembly 2b perform secondary distribution of the fluid entering the stack during stack operation, significantly increasing the end-entry air volume, thereby improving the performance of individual cells at the manifold end and ultimately improving the stack voltage consistency.

[0020] The outer shell body provided by the present invention is used for the encapsulation and encapsulation force balancing of the fuel cell stack housing. It includes inlet and outlet ports for hydrogen, air and coolant, and can provide the above three media required for the reaction of the fuel cell stack core (multiple single cells constitute the core as a whole, a single cell is composed of an electrode plate and an MEA, the core is surrounded by a shell, and the manifold end plate is connected to both the core and the shell). Attached Figure Description

[0021] Figure 1 This is a front perspective view of the end plate of the fuel cell stack provided in an embodiment of the present invention;

[0022] Figure 2 This is a three-dimensional structural diagram of the back side of the fuel cell stack end plate provided in an embodiment of the present invention;

[0023] Figure 3 This is a top view of the end plate of the fuel cell stack provided in an embodiment of the present invention;

[0024] Figure 4 for Figure 3 The diagram shows a cross-sectional view of the fuel cell stack end plate along the AA direction.

[0025] Figure 5 for Figure 3 The diagram shows a cross-sectional view of the fuel cell stack endplate along the BB direction.

[0026] Figure 6 A front structural schematic diagram of the nested main body of the fuel cell stack end plate provided in an embodiment of the present invention;

[0027] Figure 7 A schematic diagram of the back structure of the nested body of the fuel cell stack end plate provided in an embodiment of the present invention;

[0028] Figure 8 This is a three-dimensional structural diagram of a fuel cell stack provided in an embodiment of the present invention. Detailed Implementation

[0029] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed explanation of the fuel cell stack endplate and fuel cell based on the present invention. The advantages and features of the present invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, intended only to facilitate and clearly illustrate the embodiments of the present invention. Please refer to the drawings to make the objectives, features, and advantages of the present invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for illustrative purposes to aid those skilled in the art and are not intended to limit the implementation conditions of the present invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to the size, without affecting the effects and objectives achieved by the present invention, should still fall within the scope of the technical content disclosed in the present invention.

[0030] like Figures 1-3As shown, this embodiment provides a fuel cell stack end plate, including: an outer shell body 1 and a nested body; the outer shell body 1 includes a front side and a back side opposite to the front side, and the outer shell body 1 is provided with a first manifold receiving groove 20 and a second manifold receiving groove 21; the first manifold receiving groove 20 and the second manifold receiving groove 21 penetrate the outer shell body 1 from the thickness direction; the nested body includes: an insulating plate 22, a first manifold assembly 2a and a second manifold assembly 2b; the first manifold assembly 2a and the second manifold assembly 2b are respectively nested into the first manifold receiving groove 20 and the second manifold receiving groove 21, and are connected to the insulating plate 22; the insulating plate 22 is located on the back side of the outer shell body 1.

[0031] The manifold endplate housing body 1 is nested with the injection-molded body and connected to the sealing ring 11 and the core 12. It is then connected to the sealing ring 13 and the fuel cell stack housing 14 via bolts 15 to complete the fuel cell stack encapsulation. Compared to traditional methods, this reduces the risk of air leakage between the endplate insulation board (the insulation board is designed for fuel cell stack insulation) due to improper assembly. Simultaneously, the nested body also replaces the insulation board to provide insulation for the fuel cell stack. (The endplate is composed of a nested endplate housing and the injection-molded body; detailed drawings can be found in the DWG file. There is only one injection-molded body with six manifolds. The endplate is press-fitted to the core, and then the assembly holes are fitted onto the fuel cell stack encapsulation housing.)

[0032] like Figure 3 As shown, this embodiment also includes a reinforcing rib 3, which is disposed on the front side of the outer casing 1. The reinforcing rib 3 is distributed on the front side of the outer casing 1, and the reinforcing rib provides certain support for the fuel cell stack end plates to increase the uniform distribution of pressure.

[0033] like Figure 3 As shown, this embodiment also includes: a plurality of mounting holes 4, disposed on the edge of the outer casing 1, the plurality of mounting holes 4 being arranged circumferentially and at intervals along the outer casing 1. The mounting holes 4 are connected to the fuel cell stack housing 14 to provide a sealing function. This facilitates the processing of the outer casing or meets the operational requirements of the fuel cell stack assembly process.

[0034] In this embodiment, the back of the outer shell body 1 is provided with a receiving groove that matches the insulating plate 22. After the insulating plate 22 is placed in the receiving groove, the back of the outer shell body 1 is a flat surface.

[0035] like Figures 4-7As shown, the first manifold assembly 2a includes: a hydrogen inlet manifold 7, a coolant inlet manifold 6, and an air outlet manifold 5; the diameter D7 of the hydrogen inlet manifold 7 gradually increases from the front to the back; the front to the back in this article can both refer to the front and back of the outer shell body 1; the diameter D6 of the coolant inlet manifold 6 gradually increases from the front to the back; the diameter D5 of the air outlet manifold 5 gradually decreases from the front to the back.

[0036] Please continue to refer to Figures 4-7 As shown, the second manifold assembly 2b includes: a hydrogen outlet manifold 8, a coolant outlet manifold 9, and an air inlet manifold 10; the diameter D10 of the air inlet manifold 10 gradually increases from the front to the back; the diameter D9 of the coolant outlet manifold 9 gradually decreases from the front to the back; the diameter D8 of the hydrogen outlet manifold 8 gradually decreases from the front to the back.

[0037] The maximum value of the diameter D7 of the hydrogen inlet manifold 7 is less than the minimum value of the diameter D6 of the coolant inlet manifold 6, and the maximum value of the diameter D6 of the coolant inlet manifold 6 is less than the minimum value of the diameter D5 of the air outlet manifold 5. That is, the diameter of the hydrogen inlet manifold 7 is less than the diameter of the coolant inlet manifold 6, and the diameter of the coolant inlet manifold 6 is less than the diameter of the air outlet manifold 5; D7 < D6 < D5. The diameter D8 of the hydrogen outlet manifold 8 is less than the diameter D9 of the coolant outlet manifold 9, and the diameter D9 of the coolant outlet manifold 9 is less than the diameter D10 of the air inlet manifold 10, D8 < D9 < D10.

[0038] Hydrogen enters the fuel cell stack core through the hydrogen inlet manifold 7 and then is discharged through the hydrogen outlet manifold 8; coolant enters the fuel cell stack core through the coolant inlet manifold 6 and then is discharged through the coolant outlet manifold 9; air enters the fuel cell stack core through the air inlet manifold 10 and then is discharged through the air outlet manifold 5. When hydrogen enters through the hydrogen inlet manifold 7, due to its variable diameter structure, the flow rate of hydrogen slows down at the end cells, resulting in an increase in the intake air volume and an improvement in the performance of the end single cells. After hydrogen passes through the core, it is discharged by the hydrogen outlet manifold 8. Due to its variable diameter structure, it is easier to drain water at the outlet, reducing the risk of water blockage (both hydrogen and air will have water, so the drainage of both hydrogen and air is optimized). Similarly, the air path structure optimizes both the intake air volume and drainage for the inlet and outlet for supply inside the core, and can utilize substances that leak from the fluid supplied to the fuel cell stack core into the outer shell; the above-mentioned fluids include air, hydrogen, coolant, but are not limited thereto.

[0039] Optionally, the hydrogen inlet manifold 7, the coolant inlet manifold 6, and the air outlet manifold 5 are integrated; the hydrogen outlet manifold 8, the coolant outlet manifold 9, and the air inlet manifold 10 are integrated. The above components are joined using injection molding, but are not limited to this method; the fuel cell stack end plate housing is made of high-strength materials such as aluminum alloy, and the nesting body can be made of other non-metallic materials such as nylon plastic, but is not limited to this method.

[0040] On the other hand, the present invention also provides a fuel cell stack, comprising: a stack end plate as described above, a stack housing 14, and a stack core 12 disposed inside the stack housing 14; the end of the stack housing 14 is provided with a blind hole matching the mounting hole 4 on the stack end plate, and a bolt 15 is passed through the mounting hole 4 and stops in the blind hole to fix the stack end plate on the end of the stack housing 14; a sealing ring 11 is provided between the stack end plate and the stack housing 14.

[0041] The fuel cell stack core 12 includes several battery cells connected in series. Other sealing rings 13 are also provided between adjacent battery cells. The fuel cell stack core 12 can use existing fuel cell stack core structures, which will not be described in detail in this invention.

[0042] The housing body 1 is nested with the injection-molded body (nested body) and connected to the sealing ring 11 and the core 12. It is then connected to the sealing ring 13 and the fuel cell stack housing (fuel cell stack encapsulation housing) 14 via bolts 15 to complete the fuel cell stack encapsulation. Compared to traditional methods, this reduces the risk of air leakage between the end plates and insulation plates due to improper assembly. Simultaneously, the nested body also replaces the insulation plate to provide insulation for the fuel cell stack. (The end plate is composed of the end plate housing and the injection-molded body nested together. The injection-molded body has only one unit with six manifolds. The end plate is press-fitted to the core and then assembled into the fuel cell stack encapsulation housing 14 via assembly holes.)

[0043] The fuel cell stack end plate provided in this embodiment is positioned close to the end cell. This embodiment features a nested end plate design, comprising a nested outer shell, a nested main body, or a nested injection-molded insulating portion. Therefore, the fuel cell stack end plate of this invention not only integrates an insulating plate to provide good insulation performance and a certain degree of uniform pressure, but also improves the air intake of the end cell, thereby enhancing the performance of the end cell and improving the overall voltage consistency of the fuel cell stack. Furthermore, the nested structure effectively reduces the risk of air leakage between the end plate and the insulating plate.

[0044] This embodiment improves the uniformity of fluid distribution within the manifold by setting endplate manifold inlets and outlets of different diameters. No additional fluid distribution device is introduced, resulting in a simple structure and easy implementation. Specifically, the first manifold assembly 2a and the second manifold assembly 2b perform secondary distribution of the fluid entering the stack during stack operation, significantly increasing the end-entry air volume, thereby improving the performance of individual cells at the manifold end and ultimately improving the stack voltage consistency.

[0045] The outer shell body provided in this embodiment is used for the encapsulation of the fuel cell stack shell and the equalization of the encapsulation force. It includes inlet and outlet ports for hydrogen, air and coolant, and can provide the above three media required for the reaction of the fuel cell stack core (multiple single cells constitute the core as a whole, a single cell is composed of plates and MEA, the core is surrounded by a shell, and the manifold end plate is connected to both the core and the shell).

[0046] This embodiment can be used for fuel cell stack housing encapsulation, balancing the encapsulation force, and integrating the insulating plate onto the end plate (the nested main body has the function of the insulating plate, so there is no need to add another insulating plate). The end plate housing and internal nesting can reduce the risk of air leakage caused by improper installation. The manifold design inside the injection-molded main body can perform secondary distribution of fluid (variable diameter flow channel). The variable diameter structure increases the air intake of the end cells (Venturi effect), improving the performance of the end cells (the performance of the end cells is lower than that of the middle cells. Increasing the air intake can increase the voltage of the end cells. After the voltage of the end cells increases, the overall voltage consistency will improve, thus improving the overall voltage consistency of the fuel cell stack.

[0047] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0048] In the description of this invention, it should be understood that the terms "center," "height," "thickness," "upper," "lower," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0049] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0050] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0051] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A stack end plate characterized by, include: The outer shell (1) and the nested body; The outer casing (1) includes a front side and a back side opposite to the front side, and the outer casing (1) is provided with a first manifold receiving groove (20) and a second manifold receiving groove (21). The first manifold receiving groove (20) and the second manifold receiving groove (21) penetrate the outer shell body (1) from the thickness direction; The nested body includes: an insulating plate (22), a first manifold assembly (2a), and a second manifold assembly (2b); The first manifold assembly (2a) and the second manifold assembly (2b) are respectively nested into the first manifold receiving groove (20) and the second manifold receiving groove (21), and are connected to the insulating plate (22); The insulating plate (22) is located on the back of the outer casing (1); The first manifold assembly (2a) includes: a hydrogen inlet manifold (7), a coolant inlet manifold (6), and an air outlet manifold (5); The diameter of the hydrogen inlet manifold (7) gradually increases from the front to the back. The diameter of the coolant inlet manifold (6) gradually increases from the front to the back. The diameter of the air outlet manifold (5) gradually decreases from the front to the back. The second manifold assembly (2b) includes: a hydrogen outlet manifold (8), a coolant outlet manifold (9), and an air inlet manifold (10); The diameter of the air inlet manifold (10) gradually increases from the front to the back; the diameter of the coolant outlet manifold (9) gradually decreases from the front to the back; and the diameter of the hydrogen outlet manifold (8) gradually decreases from the front to the back.

2. The stack end plate of claim 1, wherein Also includes: A reinforcing rib (3) is provided on the front side of the outer shell body (1).

3. The stack end plate of claim 2, wherein A plurality of mounting holes (4) are provided on the edge of the outer shell body (1), and the plurality of mounting holes (4) are provided circumferentially and spaced apart from each other along the outer shell body (1).

4. The stack end plate of claim 3, wherein The back of the outer shell body (1) is provided with a receiving groove that matches the insulating plate (22). After the insulating plate (22) is placed in the receiving groove, the back of the outer shell body (1) is a flat surface.

5. The fuel cell stack end plate as described in claim 1, characterized in that, The maximum value of the diameter D7 of the hydrogen inlet manifold (7) is less than the minimum value of the diameter D6 of the coolant inlet manifold (6), and the maximum value of the diameter D6 of the coolant inlet manifold (6) is less than the minimum value of the diameter D5 of the air outlet manifold (5).

6. The fuel cell stack end plate as described in claim 5, characterized in that, Hydrogen enters the fuel cell stack core through the hydrogen inlet manifold (7) and is then discharged through the hydrogen outlet manifold (8); The coolant enters the fuel cell stack core through the coolant inlet manifold (6) and is then discharged through the coolant outlet manifold (9); Air enters the fuel cell stack core through the air inlet manifold (10) and is then discharged through the air outlet manifold (5).

7. The stack end plate of claim 6 wherein, The hydrogen inlet manifold (7), the coolant inlet manifold (6), and the air outlet manifold (5) are integrated; the hydrogen outlet manifold (8), the coolant outlet manifold (9), and the air inlet manifold (10) are integrated.

8. A fuel cell stack, characterized by include: The fuel cell stack end plate and fuel cell stack housing (14) are as described in any one of claims 1 to 7. The fuel cell stack core (12) is disposed inside the fuel cell stack housing (14); The end of the fuel cell stack housing (14) is provided with a blind hole that matches the mounting hole (4) on the fuel cell stack end plate. The mounting hole (4) is pierced by a bolt (15) and remains in the blind hole to fix the fuel cell stack end plate to the end of the fuel cell stack housing (14); A sealing ring (11) is provided between the fuel cell stack end plate and the fuel cell stack housing (14).

Images