A parallel fuel cell stack

Abstract

A parallel fuel cell stack proposed in the present application includes a plurality of fuel cell units connected in series; the fuel cell unit includes an upper frame, a cathode plate, a membrane assembly, an anode plate and a lower frame arranged from top to bottom; the upper frame includes at least a first upper frame and a second upper frame arranged in parallel; the first upper frame and the second upper frame are integrally formed; the cathode plate includes at least a first cathode plate and a second cathode plate arranged in parallel; the first cathode plate and the second cathode plate are integrally formed; the anode plate includes at least a first anode plate and a second anode plate arranged in parallel; the first anode plate and the second anode plate are integrally formed; the membrane assembly includes at least a first membrane assembly and a second membrane assembly arranged in parallel and independently; a first insulating frame is arranged between the first membrane assembly and the second membrane assembly. The structure of the present application can effectively reduce the contact resistance and line resistance of the stack, and the ohmic impedance and volume are both small.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a parallel fuel cell stack. Background Art

[0002] Fuel cells use the chemical conversion of fuel and oxygen to produce water to generate electrical energy. Fuel cells contain a so-called membrane electrode unit as a core component, which is a combination of a proton-conducting membrane and electrodes (anode and cathode) arranged on both sides of the membrane. In addition, gas diffusion layers (GDL) can be arranged on both sides of the membrane electrode unit on the side of the electrode facing away from the membrane. Fuel cells are generally composed of a large number of membrane electrode units arranged in a stack, and the electrical power of these membrane electrode units is superimposed on each other.

[0003] During operation of a fuel cell, fuel, especially hydrogen H2 or a mixture containing hydrogen, is directed to the anode, where the H2 is converted to H + Electrochemical oxidation of H releases electrons. Protons H are oxidized by an electrolyte or an electrically insulating membrane that separates the reaction chambers from each other in a hermetic manner. + The transport of oxygen (with or without water) from the anode compartment to the cathode compartment. The electrons prepared at the anode are directed to the cathode through an electrical circuit. Oxygen or a mixture containing oxygen is directed to the cathode in order to convert O2 to O by absorbing electrons. 2- At the same time, in the cathode chamber, the oxygen ions react with the protons transported through the membrane to produce water. Compared with other power generation systems, fuel cells achieve better efficiency through the direct conversion of chemical energy into electrical energy because there is no need to consider the Carnot factor.

[0004] Traditional fuel cells need to be connected in parallel through external mechanisms, which take up a certain amount of space, making the fuel cell larger and increasing the space required. In addition, the resistance of the external mechanism increases the internal resistance of the fuel cell, which also causes the power density of the fuel cell to decrease. Summary of the invention

[0005] Based on this, the present invention provides a parallel fuel cell stack, which aims to solve the problems that the traditional fuel cell parallel connection needs to be realized through an external mechanism, and the fuel cell has a large volume, low power density, and large internal resistance. The present application can effectively increase the effective area and power density of the plate without affecting the uniformity of airflow distribution, and effectively reduce the contact resistance of the anode and cathode plates; at the same time, the present application does not require an external mechanism to realize parallel connection, and the obtained parallel fuel cell has a small volume, low internal resistance, and high power density.

[0006] To achieve the above object, the present invention provides a parallel fuel cell stack, comprising a plurality of fuel cell units connected in series; the fuel cell unit comprises an upper frame, a cathode plate, a membrane assembly, an anode plate and a lower frame arranged from top to bottom;

[0007] The upper frame at least includes a first upper frame and a second upper frame arranged in parallel; the first upper frame and the second upper frame are integrally formed;

[0008] The cathode plate at least comprises a first cathode plate and a second cathode plate arranged in parallel; the first cathode plate and the second cathode plate are integrally formed;

[0009] The anode plate comprises at least a first anode plate and a second anode plate arranged in parallel; the first anode plate and the second anode plate are integrally formed;

[0010] The membrane assembly at least comprises a first membrane assembly and a second membrane assembly which are arranged in parallel and independently; a first insulating frame is arranged between the first membrane assembly and the second membrane assembly;

[0011] The lower frame at least includes a first lower frame and a second lower frame arranged in parallel; the first lower frame and the second lower frame are integrally formed.

[0012] Further, the fuel cell unit comprises at least a first fuel cell unit and a second fuel cell unit connected in parallel;

[0013] The first fuel cell unit comprises a first upper frame, a first cathode plate, a first membrane assembly, a first anode plate and a first lower frame arranged from top to bottom;

[0014] The second fuel cell unit includes a second upper frame, a second cathode plate, a second membrane assembly, a second anode plate and a second lower frame which are arranged from top to bottom.

[0015] Furthermore, the first fuel cell unit and the second fuel cell unit have the same structure, and the first fuel cell unit and the second fuel cell unit are arranged independently of each other.

[0016] Furthermore, the first fuel cell unit and the second fuel cell unit have flow channels, flow channel inlets and flow channel outlets that are independently arranged from each other.

[0017] Furthermore, the flow channel includes a hydrogen flow channel, an oxygen flow channel and a coolant flow channel.

[0018] Furthermore, the fuel cell unit includes at least two independently arranged hydrogen inlets, two independently arranged oxygen inlets, two independently arranged coolant inlets, two independently arranged hydrogen outlets, two independently arranged oxygen outlets and two independently arranged coolant outlets.

[0019] Furthermore, a coolant flow channel is provided on the side of the cathode plate close to the upper frame, a hydrogen flow channel is provided on the side of the cathode plate close to the membrane assembly; and an oxygen flow channel is provided on the side of the anode plate close to the membrane assembly.

[0020] Furthermore, the first membrane assembly includes a first carbon paper, a first proton membrane and a second carbon paper arranged from top to bottom; the second membrane assembly includes a third carbon paper, a second proton membrane and a fourth carbon paper arranged from top to bottom.

[0021] Furthermore, a second insulating frame is provided between the cathode plate and the anode plate, and the second insulating frame is provided at the edge of the cathode plate and the anode plate; the edge is an area 3mm-6mm away from the boundary of the cathode plate / the anode plate.

[0022] Furthermore, a sealing glue line is provided on both the first insulating frame and the second insulating frame.

[0023] Compared with the prior art, the present application has the following technical effects: the present invention arranges two first cathode plates and a second cathode plate of the same structure in parallel as one cathode plate, and arranges two first anode plates and a second anode plates of the same structure in parallel as one anode plate, so that the cathode plate, the anode plate and the membrane assembly form two first fuel cell units and a second fuel cell unit in parallel, the first fuel cell unit and the second fuel cell unit are connected in parallel to form a fuel cell unit, and a plurality of fuel cell units are connected in series to form a fuel cell stack. The fuel cell unit of the present application does not require the aid of an external structure, but can achieve parallel connection between battery cells through its own bipolar plate structure, which can effectively reduce the contact resistance and line resistance of the stack, reduce the ohmic impedance of the fuel cell, and can also effectively reduce the volume of the stack. At the same time, the narrow and long structure of the fuel cell plate can be changed to a square structure, which can well increase the effective area of ​​the plate without affecting the uniformity of airflow distribution, thereby effectively increasing the power density of the stack. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0025] Figure 1 is a schematic diagram of the longitudinal cross-sectional structure of a parallel fuel cell stack in an embodiment of the present invention;

[0026] Figure 2for Figure 1 A schematic diagram of a longitudinal cross-sectional structure of a first fuel cell unit of a parallel fuel cell stack;

[0027] Figure 3 for Figure 1 A schematic diagram of the longitudinal cross-sectional structure of the second fuel cell unit of the parallel fuel cell stack.

[0028] 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

[0029] 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 described embodiments 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 creative work are within the scope of protection of the present invention.

[0030] 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 components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0031] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0032] 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 at the same time.

[0033] 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 used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to 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.

[0034] At present, the traditional parallel connection of fuel cells needs to be realized through an external mechanism, which takes up a part of the space, making the volume of the fuel cell larger and the space required also larger. In addition, the resistance of the external mechanism increases the internal resistance of the fuel cell, which also causes the power density of the fuel cell to decrease. Based on this, it is necessary to provide a parallel fuel cell stack to solve the above technical problems.

[0035] The parallel fuel cell stack proposed by the present invention aims to solve the problems that the traditional fuel cell parallel connection needs to be realized by an external mechanism, and the fuel cell has a large volume, low power density, and large internal resistance. The present application can effectively increase the effective area and power density of the plate without affecting the uniformity of airflow distribution, and effectively reduce the contact resistance of the anode and cathode plates; at the same time, the present application does not require an external mechanism to realize parallel connection, and the obtained parallel fuel cell has a small volume, low internal resistance, and high power density.

[0036] Specifically, Figures 1 to 3 As shown, an embodiment of the present invention provides a parallel fuel cell stack, comprising a plurality of fuel cell units connected in series; the fuel cell unit comprises an upper frame 10, a cathode plate 20, a membrane assembly 30, an anode plate 40 and a lower frame 50 arranged from top to bottom;

[0037] The upper frame 10 at least includes a first upper frame 11 and a second upper frame 12 arranged in parallel; the first upper frame 11 and the second upper frame 12 are integrally formed;

[0038] The cathode plate 20 at least includes a first cathode plate 21 and a second cathode plate 22 arranged in parallel; the first cathode plate 21 and the second cathode plate 22 are integrally formed;

[0039] The anode plate 40 at least includes a first anode plate 41 and a second anode plate 42 arranged in parallel; the first anode plate 41 and the second anode plate 42 are integrally formed;

[0040] The membrane assembly 30 at least includes a first membrane assembly 31 and a second membrane assembly 32 which are arranged in parallel and independently; a first insulating frame 60 is arranged between the first membrane assembly 31 and the second membrane assembly 32;

[0041] The lower frame 50 at least includes a first lower frame 51 and a second lower frame 52 which are arranged in parallel; the first lower frame 51 and the second lower frame 52 are integrally formed.

[0042] In the present application, the first upper frame and the second upper frame, the first cathode plate and the second cathode plate, the first anode plate and the second anode plate, the first lower frame and the second lower frame are all integrally formed, which can effectively reduce the contact resistance and line resistance of the fuel cell unit and effectively improve the power density of the fuel cell unit.

[0043] Further, the fuel cell unit comprises at least a first fuel cell unit 100 and a second fuel cell unit 200 connected in parallel;

[0044] The first fuel cell unit 100 includes a first upper frame 11, a first cathode plate 21, a first membrane assembly 31, a first anode plate 41 and a first lower frame 51 arranged from top to bottom;

[0045] The second fuel cell unit 200 includes a second upper frame 12 , a second cathode plate 22 , a second membrane assembly 32 , a second anode plate 42 , and a second lower frame 52 , which are arranged from top to bottom.

[0046] Furthermore, the first fuel cell unit 100 and the second fuel cell unit 200 have the same structure, and the first fuel cell unit 100 and the second fuel cell unit 200 are independently arranged.

[0047] Furthermore, the first fuel cell unit 100 and the second fuel cell unit 200 have flow channels, flow channel inlets and flow channel outlets that are independently arranged from each other.

[0048] Furthermore, the flow channels include hydrogen flow channels A, oxygen flow channels B and coolant flow channels C. Thus, in the fuel cell unit of the present application, the left and right sides of the bipolar plate have the same two hydrogen flow fields, oxygen flow fields and coolant flow fields.

[0049] Furthermore, the fuel cell unit includes at least two independently set hydrogen inlets (not marked in the figure), two independently set oxygen inlets (not marked in the figure), two independently set coolant inlets (not marked in the figure), two independently set hydrogen outlets (not marked in the figure), two independently set oxygen outlets (not marked in the figure) and two independently set coolant outlets (not marked in the figure).

[0050] Furthermore, a coolant flow channel C is provided on the side of the cathode plate 20 close to the upper frame 10 , a hydrogen flow channel A is provided on the side of the cathode plate 20 close to the membrane assembly 30 ; and an oxygen flow channel B is provided on the side of the anode plate 40 close to the membrane assembly 30 .

[0051] Furthermore, the first membrane assembly 31 includes a first carbon paper 311, a first proton membrane 312 and a second carbon paper 313 arranged from top to bottom; the second membrane assembly 32 includes a third carbon paper 321, a second proton membrane 322 and a fourth carbon paper 323 arranged from top to bottom.

[0052] Furthermore, a second insulating frame 70 is provided between the cathode plate 20 and the anode plate 40 , and the second insulating frame 70 is provided at the edge of the cathode plate 20 and the anode plate 40 ; the edge is an area 3 mm-6 mm away from the boundary of the cathode plate 20 / the anode plate 40 .

[0053] Furthermore, the first insulating frame 60 and the second insulating frame 70 are both provided with a sealant line 80. By providing the sealant line at the contact position of each component, the fuel cell unit can be well sealed to ensure the sealing of the fuel cell unit, thereby ensuring the optimal performance of the fuel cell unit.

[0054] In the structure of the present application, the number of fuel cell units can be set to a parallel structure of three, or four or even more fuel cell units according to actual use needs.

[0055] The present invention arranges two first cathode plates and a second cathode plate of the same structure in parallel as one cathode plate, and two first anode plates and a second anode plates of the same structure in parallel as one anode plate, so that the cathode plate, the anode plate and the membrane assembly form two first fuel cell units and a second fuel cell unit in parallel, the first fuel cell unit and the second fuel cell unit are connected in parallel to form a fuel cell unit, and a plurality of fuel cell units are connected in series to form a fuel cell stack. The fuel cell unit of the present application does not require the aid of an external structure, and can achieve parallel connection between battery cells through its own bipolar plate structure, which can effectively reduce the contact resistance and line resistance of the stack, reduce the ohmic impedance of the fuel cell, and can also effectively reduce the volume of the stack. At the same time, the narrow and long structure of the fuel cell plate can be changed to a square structure, which can well increase the effective area of ​​the plate without affecting the uniformity of airflow distribution, thereby effectively increasing the power density of the stack.

[0056] 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 changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A parallel fuel cell stack, characterized in that: It comprises a plurality of fuel cell units connected in series; the fuel cell unit comprises an upper frame, a cathode plate, a membrane assembly, an anode plate and a lower frame arranged from top to bottom; The upper frame at least includes a first upper frame and a second upper frame arranged in parallel; the first upper frame and the second upper frame are integrally formed; The cathode plate at least comprises a first cathode plate and a second cathode plate arranged in parallel; the first cathode plate and the second cathode plate are integrally formed; The anode plate comprises at least a first anode plate and a second anode plate arranged in parallel; the first anode plate and the second anode plate are integrally formed; The membrane assembly at least comprises a first membrane assembly and a second membrane assembly which are arranged in parallel and independently; a first insulating frame is arranged between the first membrane assembly and the second membrane assembly; The lower frame at least includes a first lower frame and a second lower frame arranged in parallel; the first lower frame and the second lower frame are integrally formed; the fuel cell unit at least includes a first fuel cell unit and a second fuel cell unit connected in parallel; The first fuel cell unit comprises a first upper frame, a first cathode plate, a first membrane assembly, a first anode plate and a first lower frame arranged from top to bottom; The second fuel cell unit comprises a second upper frame, a second cathode plate, a second membrane assembly, a second anode plate and a second lower frame arranged from top to bottom; The first fuel cell unit and the second fuel cell unit have flow channels, flow channel inlets and flow channel outlets that are independently arranged from each other.

2. The parallel fuel cell stack according to claim 1, characterized in that: The first fuel cell unit and the second fuel cell unit have the same structure, and the first fuel cell unit and the second fuel cell unit are independently arranged; The first membrane assembly includes a first carbon paper, a first proton membrane and a second carbon paper arranged from top to bottom; the second membrane assembly includes a third carbon paper, a second proton membrane and a fourth carbon paper arranged from top to bottom.

3. The parallel fuel cell stack according to claim 2, characterized in that: The flow channels include a hydrogen flow channel, an oxygen flow channel and a coolant flow channel.

4. The parallel fuel cell stack according to claim 3, characterized in that: The fuel cell unit comprises at least two independently arranged hydrogen inlets, two independently arranged oxygen inlets, two independently arranged coolant inlets, two independently arranged hydrogen outlets, two independently arranged oxygen outlets and two independently arranged coolant outlets.

5. The parallel fuel cell stack according to claim 4, characterized in that: A coolant flow channel is arranged on the side of the cathode plate close to the upper frame, a hydrogen flow channel is arranged on the side of the cathode plate close to the membrane assembly; an oxygen flow channel is arranged on the side of the anode plate close to the membrane assembly.

6. The parallel fuel cell stack according to claim 1, characterized in that: A second insulating frame is provided between the cathode plate and the anode plate, and the second insulating frame is provided at the edge of the cathode plate and the anode plate; the edge is an area 3 mm-6 mm away from the boundary of the cathode plate / the anode plate.

7. The parallel fuel cell stack according to claim 6, characterized in that: Sealing glue lines are arranged on the first insulating frame and the second insulating frame.

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