Fuel cell end plate and electric pile structure

Abstract

The utility model relates to a fuel cell end plate, which is suitable for a fuel cell electric pile core and comprises an end plate body, a plurality of first manifolds arranged at one end of the end plate body and a plurality of second manifolds arranged at the other end of the end plate body, one end of the end plate body is provided with a plurality of first fluid cavities penetrating through the end plate body, and the first fluid cavities are arranged independently. The first manifold is arranged on the first fluid cavity; the first manifolds and the first fluid cavities are arranged in a one-to-one correspondence mode. And in the direction from the first manifold to the first fluid cavity, the first manifold and the first fluid cavity are connected to form a first obtuse angle. The utility model also provides a fuel cell stack structure. The end plate is simple in structure, relatively low in cost and small in processing difficulty, and can effectively solve the problem that the head and the tail of the electric pile are low while the strength of the end plate is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a fuel cell end plate and a fuel cell stack structure. Background Art

[0002] A perfluorosulfonic acid proton exchange membrane (PEM) fuel cell is a device that converts the chemical energy in hydrogen into electrical energy. The hydrogen at the anode undergoes a hydrogen oxidation reaction, and the protons produced pass through the proton exchange membrane and combine with the oxygen at the cathode to undergo an oxygen reduction reaction, thereby generating a potential difference and supplying power to the outside. Each PEM fuel cell consists of two major parts: the membrane electrode and the bipolar plate. The latter is where the electrochemical reaction occurs, including the anode diffusion layer, anode catalyst layer, proton exchange membrane, cathode catalyst layer, and cathode diffusion layer. The output of a single cell is generally less than 1.8W / cm 2 Therefore, in order to achieve higher power output, multiple single-cell batteries need to be stacked together to form a fuel cell stack. To ensure the tightness and stability of the stack, the two sides of the core need to be fixed with end plates and screws / steel belts.

[0003] The fuel cell stack consists of a front-end plate and a rear-end plate. The front-end plate forms a fluid cavity and a force-applying surface, which, on the one hand, ensures the force transmission of the stack and plays a role in tightening the stack; on the other hand, the front-end plate needs to be designed with inlet and outlet pipe interfaces and cavities for hydrogen, air, and coolant to ensure the introduction and discharge of the three. The rear-end plate is set close to the tail plate and current collecting plate of the core, and mainly plays a tightening role.

[0004] Current collectors are placed on both sides of the core to conduct the current from both sides of the series-connected fuel cell core, which is the output voltage of the stack. The stack has very high insulation requirements, so an insulating plate is placed between the current collector and the end plate, or the end plate is directly made of a material with insulating properties such as engineering plastic. The stack must meet requirements such as mechanical strength, thermal cycling, vibration and impact, and fatigue life, which places very high demands on the structure of the end plate. The end plate contains springs and spring cover plates to control the tightening force of the core within a certain range. The front and rear end plates are sealed with steel strips or screws, and the sealing force is transmitted to the core, ensuring that each single cell, membrane electrode, and bipolar plate in the core are tightly fitted, limiting the relative movement of the core while ensuring airtightness, and minimizing contact resistance.

[0005] Currently, the power output for applications such as heavy-duty trucks, mining trucks, and engineering vehicles generally exceeds 100 kW, and for applications such as energy storage and power generation, single stacks can even exceed 200 kW. The number of cells in the stack core is even higher, sometimes exceeding 300, which inevitably leads to the risk of low voltage per cell. Furthermore, since the temperature near the end plates is lower than that of the core, catalyst activity is weakened, which can easily lead to low voltage at the front and rear ends. On the one hand, some stack manufacturers place dummy membrane electrodes at the front and rear ends, sacrificing their power output to ensure temperature uniformity in the core, or place electric heaters on the end plates to maintain temperature uniformity at the front and rear ends. On the other hand, to improve hydrogen utilization, unreacted hydrogen is often mixed with fresh hydrogen and then continuously fed into the stack. The temperature difference between the high-temperature and high-humidity recycled hydrogen and the dry, low-temperature fresh hydrogen can cause water vapor to condense into liquid water, especially near the end plates. Once liquid water enters the anode, it can cause flooding, resulting in gas shortages and ultimately low voltage at the front and rear ends. For this reason, many companies have made improvements to the hydrogen subsystem, either by increasing the gas-liquid separation capability or by performing external heat exchange on the recycled hydrogen to lower the temperature and ultimately reduce the production of liquid water.

[0006] However, previous studies and reports have ignored the phenomenon of low head and tail caused by uneven introduction of gas. In common fuel cell products, the manifold configured on the end plate is on the same vertical line as the main channel of the core, and the hydrogen or air inlet is easier to enter the main channel; however, according to the analysis of the gas flow direction and the pressure difference between the main channel and the plate flow field, the gas flow into the plate close to the front end plate is relatively small, which is another important reason for the low head. Moreover, the end plate structure of fuel cell products on the market focuses on solving mechanical needs. Most of them can meet the requirements of mechanical strength, but there is a lack of research on the introduction of fuel fluid. The design of the end plate ignores the design of the fluid cavity. Utility Model Content

[0007] Based on this, the present invention provides a fuel cell end plate and stack structure, aiming to solve the technical problem of uneven gas introduction in existing end plates, such as low head and tail. The present invention has a simple structure and low cost, and can effectively solve the problem of low head and tail in the stack.

[0008] To achieve the above objectives, on the one hand, the embodiments of the present invention provide the following technical solutions: a fuel cell end plate, suitable for a fuel cell stack, comprising an end plate body, a plurality of first manifolds provided at one end of the end plate body, and a plurality of second manifolds provided at the other end of the end plate body;

[0009] One end of the end plate body is provided with a plurality of first fluid cavities penetrating the end plate body, and the plurality of first fluid cavities are independently arranged; the first manifold is arranged on the first fluid cavity; the first manifold and the first fluid cavity are arranged in a one-to-one correspondence; from the first manifold to the first fluid cavity, the first manifold is connected to the first fluid cavity to form a first obtuse angle.

[0010] As a preferred embodiment, the inner wall of each first fluid cavity is provided with a first curvature. By providing the first curvature in the first fluid cavity, the angle difference between the first manifold and the first fluid cavity can be increased, thereby further increasing the gas flow into the battery near the front plate.

[0011] As a preferred embodiment, a plurality of the first manifolds are arranged in parallel with each other; a plurality of the first fluid chambers are arranged in parallel with each other.

[0012] As a preferred embodiment, the first fluid cavity is arranged in one-to-one correspondence with the first channel of the fuel cell stack; from the first fluid cavity to the fuel cell stack, the first fluid cavity is connected to the first channel of the fuel cell stack to form a second obtuse angle.

[0013] As a preferred embodiment, the other end of the end plate body is provided with a plurality of second fluid cavities that penetrate the end plate body, and the plurality of second fluid cavities are independently arranged; the second manifold is arranged on the second fluid cavity; the second manifold and the second fluid cavity are arranged in a one-to-one correspondence; from the second manifold to the second fluid cavity, the second manifold is connected to the second fluid cavity to form a third obtuse angle.

[0014] As a preferred embodiment, the inner wall of each second fluid cavity is provided with a second curvature. By providing the second curvature in the second fluid cavity, the angle difference between the second manifold and the second fluid cavity can be increased, thereby further increasing the gas flow into the battery near the front plate.

[0015] As a preferred embodiment, a plurality of the second manifolds are arranged in parallel with each other; and a plurality of the second fluid chambers are arranged in parallel with each other.

[0016] As a preferred embodiment, the second fluid cavity is arranged in one-to-one correspondence with the second channel of the fuel cell stack core; from the second fluid cavity to the fuel cell stack core, the second fluid cavity is connected to the second channel of the fuel cell stack core to form a fourth obtuse angle.

[0017] As a preferred embodiment, the first manifold is an inflow manifold, the first fluid cavity is an inflow fluid cavity, and the first channel is an inflow channel; the second manifold is an outflow manifold, the second fluid cavity is an outflow fluid cavity, and the second channel is an outflow channel.

[0018] As a preferred embodiment, the fuel cell end plate is an air intake end plate (ie, a front end plate).

[0019] On the other hand, the present application also provides a fuel cell stack structure, wherein the fuel cell stack includes the fuel cell end plate.

[0020] As a preferred embodiment, the fuel cell stack structure includes a first end plate, a fuel cell stack core, a second end plate and several binding straps; the first end plate is arranged at one end of the fuel cell stack core, and the second end plate is arranged at the other end of the fuel cell stack core; one end of each of the binding straps is arranged on the first end plate, and the other end is arranged on the second end plate, and the binding straps are enclosed and arranged on the outside of the fuel cell stack core; several of the binding straps are arranged parallel to each other; the first end plate is the fuel cell end plate.

[0021] The beneficial effects achieved by the present invention are as follows: in the structure of the present application, by connecting the first manifold with the first fluid cavity to form a first obtuse angle, connecting the first fluid cavity with the first channel of the fuel cell stack to form a second obtuse angle, connecting the second manifold with the second fluid cavity to form a third obtuse angle, and connecting the second fluid cavity with the second channel of the fuel cell stack to form a fourth obtuse angle, while ensuring the strength of the end plate body, the center of the first manifold (or the second manifold) and the first channel (or the second channel) of the stack are not on the same vertical line, which is more conducive to the gas entering the single cell (especially the single cell near the front end plate area), thereby effectively increasing the gas flow entering the cell near the front end plate, thereby effectively improving the problem of low voltage of the first cell of the stack due to low fuel flow. The present application has a simple structure, low cost, and low processing difficulty. While ensuring the strength of the end plate, it can effectively solve the problem of low voltage of the first and last cells of the stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0023] Figure 1 This is a schematic diagram of the overall structure of a fuel cell end plate according to an embodiment of the present invention;

[0024] Figure 2 for Figure 1 Schematic diagram of the cross-sectional structure of a fuel cell end plate;

[0025] Figure 3 To adopt Figure 1 A schematic diagram of the overall structure of a fuel cell stack structure having a fuel cell end plate;

[0026] Figure 4 for Figure 3 A schematic cross-sectional view of a fuel cell stack structure;

[0027] Figure 5 is a schematic cross-sectional structural diagram of a fuel cell end plate according to another embodiment;

[0028] Figure 6 To adopt Figure 5 Schematic diagram of the cross-sectional structure of the fuel cell stack structure of the fuel cell end plate.

[0029] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, top, bottom...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0032] In this application, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0033] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element.

[0034] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features specified as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0035] On the one hand, if Figures 1 to 4 As shown, the embodiment of the present invention provides a fuel cell end plate suitable for a fuel cell stack 100, comprising an end plate body 10, a plurality of first manifolds 20 provided at one end of the end plate body 10, and a plurality of second manifolds 30 provided at the other end of the end plate body 10;

[0036] One end of the end plate body 10 is provided with a plurality of first fluid cavities 11 that penetrate the end plate body 10, and the plurality of first fluid cavities 11 are independently arranged; the first manifold 20 is arranged on the first fluid cavity 11; the first manifold 20 and the first fluid cavity 11 are arranged in a one-to-one correspondence; from the first manifold 20 to the first fluid cavity 11, the first manifold 20 is connected to the first fluid cavity 11 to form a first obtuse angle.

[0037] In the structure of the present application, the first manifold 20 is an inlet manifold. There are three first manifolds 20, including a hydrogen inlet manifold 21, an air inlet manifold 22 and a coolant inlet manifold 23. The hydrogen inlet manifold 21, the air inlet manifold 22 and the coolant inlet manifold 23 are all arranged on the first manifold base 24, and the hydrogen inlet manifold 21, the air inlet manifold 22, the coolant inlet manifold 23 and the first manifold base 24 are integrally formed. The hydrogen inlet manifold 21, the air inlet manifold 22 and the coolant inlet manifold 23 are all arranged through the first manifold base 24.

[0038] Correspondingly, the first fluid cavity 11 is an inflow fluid cavity, and the first fluid cavity 11 is provided with three, including a hydrogen inflow fluid cavity 111, an air inflow fluid cavity 112 and a coolant inflow fluid cavity 113, wherein the hydrogen inflow fluid cavity 111 is connected to the hydrogen inflow manifold 21 to form a first obtuse angle, the air inflow fluid cavity 112 is connected to the air inflow manifold 22 to form a first obtuse angle, and the coolant inflow fluid cavity 113 is connected to the coolant inflow manifold 23 to form a first obtuse angle.

[0039] The structure of the present application forms the above-mentioned first obtuse angle so that the first manifold and the first fluid cavity are not on the same vertical plane. While ensuring the strength of the end plate body, it is more conducive to the entry of gas into the single cell (especially the single cell near the front end plate area), thereby effectively increasing the gas flow entering the battery near the front end plate.

[0040] like Figures 5 and 6 As shown, in another embodiment, the inner wall of each first fluid cavity 11 is provided with a first curvature A. By providing the first curvature in the first fluid cavity 11, the angle difference formed between the first manifold 20 and the first fluid cavity 11 can be increased, thereby further increasing the gas flow entering the battery near the front plate.

[0041] As a preferred embodiment, a plurality of the first manifolds 20 are arranged in parallel with each other; a plurality of the first fluid chambers 11 are arranged in parallel with each other.

[0042] As a preferred embodiment, the first fluid cavity 11 is arranged in one-to-one correspondence with the first channel 101 of the fuel cell stack core 100; from the first fluid cavity 11 to the fuel cell stack core 100, the first fluid cavity 11 is connected to the first channel 101 of the fuel cell stack core 100 to form a second obtuse angle.

[0043] In traditional fuel cell stack structures, the manifold and the main channel of the stack core are on the same vertical plane. According to Bernoulli's equation, the greater the gas flow velocity, the lower the pressure. This can easily cause the flow rate to the individual cells near the front end plate to be too low, ultimately leading to low voltage. The structure of the present application connects the first fluid cavity 11 with the first channel 101 of the fuel cell stack core 100 to form the aforementioned second obtuse angle, so that the first fluid cavity and the first channel are not on the same vertical plane, further effectively improving the gas flow into the cells near the front end plate.

[0044] As a preferred embodiment, the other end of the end plate body 10 is provided with a plurality of second fluid cavities 12 that penetrate the end plate body 10, and the plurality of second fluid cavities 12 are independently arranged; the second manifold 30 is arranged on the second fluid cavity 12; the second manifold 30 and the second fluid cavity 12 are arranged one by one; from the second manifold 30 to the second fluid cavity 12, the second manifold 30 is connected to the second fluid cavity 12 to form a third obtuse angle.

[0045] In the structure of the present application, the second manifold 30 is an outflow manifold, and there are three second manifolds 30, including a hydrogen outflow manifold 31, an air outflow manifold 32 and a coolant outflow manifold 33. The hydrogen outflow manifold 31, the air outflow manifold 32 and the coolant outflow manifold 33 are all arranged on the second manifold base 34, and the hydrogen outflow manifold 31, the air outflow manifold 32 and the coolant outflow manifold 33 are integrally formed with the second manifold base 34, and the hydrogen outflow manifold 31, the air outflow manifold 32 and the coolant outflow manifold 33 are all arranged through the second manifold base 34.

[0046] Correspondingly, the second fluid cavity 12 is an outflow fluid cavity, and the second fluid cavity 12 is provided with three, including a hydrogen outflow fluid cavity 121, an air outflow fluid cavity 122 and a coolant outflow fluid cavity 123, wherein the hydrogen outflow fluid cavity 121 is connected to the hydrogen outflow manifold 31 to form a third obtuse angle, the air outflow fluid cavity 122 is connected to the air outflow manifold 32 to form a third obtuse angle, and the coolant outflow fluid cavity 123 is connected to the coolant outflow manifold 33 to form a third obtuse angle.

[0047] The structure of the present application forms the above-mentioned third obtuse angle so that the second manifold and the second fluid cavity are not on the same vertical plane, which is more conducive to the flow of gas while ensuring the strength of the end plate body.

[0048] like Figures 5 and 6 As shown, in another embodiment, the inner wall of each second fluid cavity 12 is provided with a second curvature B. By providing the second curvature in the second fluid cavity 12, the angle difference formed between the second manifold 30 and the second fluid cavity 12 can be increased, thereby further increasing the gas flow entering the battery near the front plate.

[0049] As a preferred embodiment, a plurality of second manifolds 30 are arranged in parallel with each other; a plurality of second fluid chambers 12 are arranged in parallel with each other.

[0050] As a preferred embodiment, the second fluid cavity 12 is provided in a one-to-one correspondence with the second channel 102 of the fuel cell stack 100; from the second fluid cavity 12 toward the fuel cell stack 100, the second fluid cavity 12 and the second channel 102 of the fuel cell stack 100 are connected to form a fourth obtuse angle. The structure of the present application forms the aforementioned fourth obtuse angle by connecting the second fluid cavity 12 with the second channel 102 of the fuel cell stack 100, so that the second fluid cavity and the second channel are not on the same vertical plane, further effectively improving gas flow.

[0051] As a preferred embodiment, the first manifold 20 is an inflow manifold, the first fluid cavity 11 is an inflow fluid cavity, and the first channel 101 is an inflow channel; the second manifold 30 is an outflow manifold, the second fluid cavity 12 is an outflow fluid cavity, and the second channel 102 is an outflow channel.

[0052] As a preferred embodiment, the fuel cell end plate is an air intake end plate (ie, a front end plate).

[0053] On the other hand, the present application also provides a fuel cell stack structure, wherein the fuel cell stack includes the fuel cell end plate.

[0054] As a preferred embodiment, the fuel cell stack structure includes a first end plate 200, a fuel cell stack core 100, a second end plate 300 and several bundling straps 400; the first end plate 200 is arranged at one end of the fuel cell stack core 100, and the second end plate 300 is arranged at the other end of the fuel cell stack core 100; one end of each of the bundling straps 400 is arranged on the first end plate 200, and the other end is arranged on the second end plate 300, and the bundling straps 400 are enclosed and arranged on the outside of the fuel cell stack core 100; several of the bundling straps 400 are arranged parallel to each other; the first end plate 200 is the fuel cell end plate.

[0055] In the structure of the present application, by connecting the first manifold with the first fluid cavity to form a first obtuse angle, connecting the first fluid cavity with the first channel of the fuel cell stack to form a second obtuse angle, connecting the second manifold with the second fluid cavity to form a third obtuse angle, and connecting the second fluid cavity with the second channel of the fuel cell stack to form a fourth obtuse angle, while ensuring the strength of the end plate body, the center of the first manifold (or the second manifold) and the first channel (or the second channel) of the stack are not on the same vertical line, which is more conducive to the gas entering the single cell (especially the single cell near the front end plate area), thereby effectively increasing the gas flow entering the cell near the front end plate, thereby effectively improving the problem of low voltage of the first single cell of the stack due to low fuel flow. The present application has a simple structure, low cost, and low processing difficulty. While ensuring the strength of the end plate, it can effectively solve the problem of low voltage of the first and last cells of the stack.

[0056] Throughout this specification, references to terms such as "one embodiment" and "example" indicate that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of these terms do not necessarily refer to the same embodiment or example.

[0057] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0058] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made by using the contents of the present invention specification and drawings under the utility model concept, or direct / indirect application in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A fuel cell end plate, characterized in that: Suitable for fuel cell stack core, comprising an end plate body, a plurality of first manifolds arranged at one end of the end plate body, and a plurality of second manifolds arranged at the other end of the end plate body; One end of the end plate body is provided with a plurality of first fluid cavities penetrating the end plate body, and the plurality of first fluid cavities are independently arranged; the first manifold is arranged on the first fluid cavity; the first manifold and the first fluid cavity are arranged in a one-to-one correspondence; from the first manifold to the first fluid cavity, the first manifold is connected to the first fluid cavity to form a first obtuse angle.

2. The fuel cell end plate according to claim 1, characterized in that: The inner wall of each of the first fluid cavities is provided with a first curvature.

3. The fuel cell end plate according to claim 1, wherein: The plurality of first manifolds are arranged in parallel with each other; the plurality of first fluid chambers are arranged in parallel with each other.

4. The fuel cell end plate according to claim 1, wherein: The first fluid cavity and the first channel of the fuel cell stack are arranged in a one-to-one correspondence; from the first fluid cavity to the fuel cell stack, the first fluid cavity and the first channel of the fuel cell stack are connected to form a second obtuse angle.

5. The fuel cell end plate according to claim 4, characterized in that: The other end of the end plate body is provided with a plurality of second fluid cavities that penetrate the end plate body, and the plurality of second fluid cavities are independently arranged; the second manifold is arranged on the second fluid cavity; the second manifold and the second fluid cavity are arranged in a one-to-one correspondence; from the second manifold to the second fluid cavity, the second manifold is connected to the second fluid cavity to form a third obtuse angle.

6. The fuel cell end plate according to claim 5, characterized in that: The inner wall of each second fluid cavity is provided with a second curvature.

7. The fuel cell end plate according to claim 5, characterized in that: The plurality of second manifolds are arranged in parallel with each other; and the plurality of second fluid chambers are arranged in parallel with each other.

8. The fuel cell end plate according to claim 5, characterized in that: The second fluid cavity is arranged in one-to-one correspondence with the second channel of the fuel cell stack; from the second fluid cavity to the fuel cell stack, the second fluid cavity is connected to the second channel of the fuel cell stack to form a fourth obtuse angle.

9. The fuel cell end plate according to claim 8, characterized in that: The first manifold is an inflow manifold, the first fluid cavity is an inflow fluid cavity, and the first channel is an inflow channel; the second manifold is an outflow manifold, the second fluid cavity is an outflow fluid cavity, and the second channel is an outflow channel; The fuel cell end plate is an air intake end plate.

10. A fuel cell stack structure, characterized in that: The fuel cell stack comprises the fuel cell end plate according to any one of claims 1 to 9.

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