A fuel cell stack

Abstract

The application provides a fuel cell stack, which comprises a plurality of fuel cell units connected in series, the fuel cell units comprising first fuel cell units and second fuel cell units connected in series; 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 insulating frame arranged from top to bottom; the second fuel cell unit comprises a second insulating frame, a second cathode plate, a second membrane assembly, a second anode plate and a first lower frame arranged from top to bottom; the first anode plate and the second cathode plate are integrally arranged; the second membrane assembly and the first insulating frame are in abutment; and the first membrane assembly and the second insulating frame are in abutment. The bipolar plate is of a left-right structure, which can improve the effective area of the bipolar plate, thereby improving the power density of the fuel cell, eliminating the contact resistance of the traditional up-down structure bipolar plate and effectively reducing the ohmic impedance of the fuel cell.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fuel cell, in particular to a fuel cell stack. BACKGROUND

[0002] Fuel cells use the chemical conversion of fuel and oxygen to produce water for generating electric energy, and comprise membrane electrode units as core components. The membrane electrode unit 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 provided on both sides of the membrane electrode unit and arranged on the sides of the electrodes facing away from the membrane. A fuel cell generally comprises a large number of membrane electrode units arranged in a stack, and the electric power of these membrane electrode units is superimposed on each other.

[0003] In the operation of a fuel cell, fuel, in particular hydrogen H2 or a hydrogen-containing gas mixture, is directed to the anode, where the electrochemical oxidation of H2 to H+ + is carried out to release electrons. Protons H + are transported from the anode chamber to the cathode chamber (combined with water or without water) by an electrolyte or a membrane that separates the reaction chambers from each other and is electrically insulating, and the electrons produced at the anode are directed to the cathode through an electric circuit. Oxygen or an oxygen-containing gas mixture is directed to the cathode to complete the reduction from O2 to O 2- by absorbing electrons, while the oxygen ions in the cathode chamber react with the protons transported through the membrane to produce water. Compared with other power generation systems, fuel cells directly convert chemical energy into electrical energy, achieving better efficiency without considering the Carnot factor.

[0004] Traditional fuel cells are composed of a plurality of bipolar plate membrane electrode unit stacks, and the cooling water flow field in the bipolar plate is formed by bonding two single plates with water flow channels. Since the bipolar plate is formed by bonding two single plates, there is contact resistance between the anode and cathode plates, and the ohmic loss of the fuel cell is also large. SUMMARY

[0005] Therefore, the present application provides a fuel cell stack to solve the problems of contact resistance, large ohmic loss, etc. caused by the stacking of anode and cathode plates. The present application can effectively improve the effective area and power density of the polar plate without affecting the uniformity of air flow distribution, eliminate the contact resistance caused by the stacking of anode and cathode plates, effectively reduce the ohmic impedance of the fuel cell, and further improve the power density of the fuel cell.

[0006] To achieve the above-mentioned purpose, the present application provides a fuel cell stack, comprising a plurality of fuel cell units connected in series, wherein the fuel cell units comprise a first fuel cell unit and a second fuel cell unit connected in series.

[0007] 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 insulating frame arranged from top to bottom;

[0008] The second fuel cell unit comprises a second insulating frame, a second cathode plate, a second membrane assembly, a second anode plate and a first lower frame arranged from top to bottom;

[0009] The first anode plate and the second cathode plate are integrally formed;

[0010] The second membrane assembly and the first insulating frame abut; the first membrane assembly and the second insulating frame abut.

[0011] Further, the fuel cell stack further comprises a third anode plate integrally formed with the first cathode plate, the third anode plate abutting the second insulating frame; the third anode plate is connected with the positive electrode of the load.

[0012] Further, the top end of the third anode plate is provided with a second upper frame integrally formed with the first upper frame, and the second upper frame abuts the third anode plate.

[0013] Further, the fuel cell stack further comprises a third cathode plate integrally formed with the second anode plate, the third cathode plate abutting the first insulating frame; the third cathode plate is connected with the negative electrode of the load. In this way, through the connection of the third anode plate, the third cathode plate and the positive and negative electrodes of the load, the effect of conducting electricity is achieved.

[0014] Further, the bottom end of the third cathode plate is provided with a second lower frame integrally formed with the first lower frame, and the second lower frame abuts the third cathode plate.

[0015] Further, the first membrane assembly comprises a first carbon paper, a first proton membrane and a second carbon paper arranged from top to bottom; the second membrane assembly comprises a third carbon paper, a second proton membrane and a fourth carbon paper arranged from top to bottom.

[0016] Further, a second insulating frame is arranged between the first cathode plate and the first anode plate, and between the second cathode plate and the second anode plate; the second insulating frame is arranged at the edge of the first cathode plate and the first anode plate, or the second insulating frame is arranged at the edge of the second cathode plate and the second anode plate.

[0017] Further, the edge is a region 3mm-6mm away from the boundary of the first cathode plate / the first anode plate / the second cathode plate / the second anode plate.

[0018] Further, the first and second insulating frames are provided with a first sealant line.

[0019] Further, the first and second insulating frames are provided with a first sealant line.

[0020] Further, the first and second fuel cell units are provided with independent flow channels, including hydrogen flow channels, oxygen flow channels and cooling liquid flow channels.

[0021] Further, the first and second insulating frames are provided with a first sealant line.

[0022] Further, the first and second insulating frames are provided with a first sealant line.

[0023] Further, the first and second insulating frames are provided with a first sealant line.

[0024] Further, the first and second insulating frames are provided with a first sealant line. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0026] Figure 1 FIG. 1 is a longitudinal sectional view of a fuel cell stack according to an embodiment of the present application.

[0027] Figure 2 Fig. 1 is a schematic longitudinal cross-sectional view of a first fuel cell unit of a fuel cell stack according to the present application; Figure 1

[0028] Figure 3 Fig. 2 is a schematic longitudinal cross-sectional view of a second fuel cell unit of a fuel cell stack according to the present application. Figure 1 The objectives, features and advantages of the present application will be further understood from the following detailed description of the embodiments, taken in conjunction with the accompanying drawings.

[0029] DETAILED DESCRIPTION DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0031] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, top, bottom, etc.), the directional indications are only used to explain the relative positional relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly.

[0032] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, can be fixedly connected, or can be detachably connected, or can be integrated; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

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

[0034] ​In addition, if the description of "first", "second" and the like is involved in the embodiments of the present application, the description of "first", "second" and the like is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can be explicitly or implicitly included at least one of the features. In addition, the technical solutions of various embodiments can be combined with each other, but it must be based on the realization of the ordinary skilled in the art, when the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist, nor in the protection scope required by the present application.

[0035] At present, the traditional fuel cell is formed by stacking a plurality of bipolar plates and membrane electrodes, and the cooling water flow field in the bipolar plate is formed by bonding two single plates with water flow channels. Since the bipolar plate of this structure is formed by bonding two single plates, there is a contact resistance between the cathode and anode plates, which increases the ohmic loss of the fuel cell. Therefore, it is necessary to provide a fuel cell stack to solve the above technical problems.

[0036] The fuel cell stack provided by the present application aims to solve the problems of the traditional fuel cell, such as the contact resistance caused by the stacking of the bipolar plate and the membrane electrode, and the large ohmic loss of the battery. The present application can effectively improve the effective area and power density of the bipolar plate without affecting the uniformity of air flow distribution, eliminate the contact resistance caused by the stacking of the cathode and anode plates, effectively reduce the ohmic impedance of the fuel cell, and further improve the overall power density of the fuel cell stack.

[0037] Specifically, as shown in Figures 1 to 3 The fuel cell stack provided by the present application comprises a plurality of fuel cell units connected in series, and the fuel cell unit comprises a first fuel cell unit 10 and a second fuel cell unit 20 connected in series.

[0038] The first fuel cell unit 10 comprises a first upper frame 11, a first cathode plate 12, a first membrane assembly 13, a first anode plate 14 and a first insulating frame 15 arranged from top to bottom.

[0039] The second fuel cell unit 20 comprises a second insulating frame 21, a second cathode plate 22, a second membrane assembly 23, a second anode plate 24 and a first lower frame 25 arranged from top to bottom.

[0040] The first anode plate 14 and the second cathode plate 22 are integrally formed;

[0041] The second membrane assembly 23 and the first insulating frame 15 abut; the first membrane assembly 13 and the second insulating frame 21 abut.

[0042] Further, the fuel cell stack further comprises a third anode plate 30 integrally formed with the first cathode plate 12, the third anode plate 30 abutting against the second insulating frame 21; the third anode plate 30 is connected with the positive pole of the load (not shown in the figure).

[0043] Further, the top end of the third anode plate 30 is provided with a second upper frame 40 integrally formed with the first upper frame 11, and the second upper frame 40 abuts against the third anode plate 30.

[0044] Further, the fuel cell stack further comprises a third cathode plate 50 integrally formed with the second anode plate 24, the third cathode plate 50 abutting against the first insulating frame 15; the third cathode plate 50 is connected with the negative pole of the load. In this way, through the connection of the third anode plate, the third cathode plate and the positive and negative poles of the load, the function of conducting electricity is achieved.

[0045] Further, the bottom end of the third cathode plate 50 is provided with a second lower frame 60 integrally formed with the first lower frame 25, and the second lower frame 60 abuts against the third cathode plate 50.

[0046] Further, the first membrane assembly 13 comprises a first carbon paper 131, a first proton membrane 132 and a second carbon paper 133 arranged from top to bottom; the second membrane assembly 23 comprises a third carbon paper 231, a second proton membrane 232 and a fourth carbon paper 233 arranged from top to bottom.

[0047] Further, the third insulating frame 70 is arranged at the edge of the first cathode plate 12 and the first anode plate 14, or the third insulating frame 70 is arranged at the edge of the second cathode plate 22 and the second anode plate 24.

[0048] Further, the edge is a region 3mm-6mm away from the boundary of the first cathode plate 12 / the first anode plate 14 / the second cathode plate 22 / the second anode plate 24.

[0049] Further, the first insulating frame 15, the second insulating frame 21 and the third insulating frame 70 are all provided with a first sealant line 80.

[0050] Further, a second sealing glue line 90 is arranged between the first cathode plate 12 and the first upper frame 11, between the third anode plate 30 and the second upper frame 40, between the third cathode plate 50 and the second lower frame 60, and between the second anode plate 24 and the first lower frame 25.

[0051] Further, the first fuel cell unit 10 and the second fuel cell unit 20 have flow channels arranged independently of each other, which include an oxygen flow channel A, a hydrogen flow channel B, and a cooling liquid flow channel C.

[0052] Further, the first cathode plate 12 is provided with the cooling liquid flow channel C on the side close to the first upper frame 11, the second cathode plate 22 is provided with the cooling liquid flow channel C on the side close to the second insulating frame 70, and the third cathode plate 50 is provided with the cooling liquid flow channel C on the side close to the first insulating frame 15.

[0053] Further, the first cathode plate 12 is provided with the oxygen flow channel A on the side close to the first membrane assembly 13, the second cathode plate 22 is provided with the oxygen flow channel A on the side close to the second membrane assembly 23, and the third cathode plate 50 is provided with the oxygen flow channel A on the side close to the second lower frame 60.

[0054] Further, the first anode plate 14 is provided with the hydrogen flow channel B on the side close to the first membrane assembly 13, the second anode plate 24 is provided with the hydrogen flow channel B on the side close to the second membrane assembly 23, and the third anode plate 30 is provided with the hydrogen flow channel B on the side close to the second upper frame 40.

[0055] The application changes the bipolar plate from the upper and lower structure to the left and right structure, changes the fuel cell bipolar plate from the long and narrow structure to the square structure, improves the effective area of the bipolar plate without affecting the uniformity of the airflow distribution, thereby improving the power density of the fuel cell; since the bipolar plate adopts the left and right structure formed integrally, the contact resistance of the traditional upper and lower structure bipolar plate is eliminated, the ohmic impedance of the fuel cell is effectively reduced, thereby further improving the overall power density of the fuel cell stack.

[0056] The above only describes the preferred embodiments of the application, and does not limit the patent scope of the application, and any equivalent structural transformation made according to the application concept, or direct / indirect application in other related technical fields is included in the patent protection scope of the application.

Claims

1. A fuel cell stack, characterized by, The fuel cell stack comprises a plurality of fuel cell units connected in series, the fuel cell units comprising first and second fuel cell units connected in series; The first fuel cell unit comprises, from top to bottom, a first upper frame, a first cathode plate, a first membrane assembly, a first anode plate, and a first insulating frame; The second fuel cell unit comprises, from top to bottom, a second insulating frame, a second cathode plate, a second membrane assembly, a second anode plate, and a first lower frame; The first anode plate and the second cathode plate are integrally formed; the fuel cell stack further comprises a third anode plate integrally formed with the first cathode plate; the fuel cell stack further comprises a third cathode plate integrally formed with the second anode plate; The second membrane assembly and the first insulating frame are in abutment; the first membrane assembly and the second insulating frame are in abutment; The first and second fuel cell units have flow channels arranged independently of each other; the flow channels comprise hydrogen flow channels, oxygen flow channels, and cooling liquid flow channels.

2. The fuel cell stack of claim 1, wherein The third anode plate is in abutment with the second insulating frame; the third anode plate is connected to a positive electrode of a load; the top end of the third anode plate is provided with a second upper frame integrally formed with the first upper frame, and the second upper frame is in abutment with the third anode plate.

3. The fuel cell stack of claim 2, wherein The third cathode plate is in abutment with the first insulating frame; the third cathode plate is connected to a negative electrode of a load; The bottom end of the third cathode plate is provided with a second lower frame integrally formed with the first lower frame, and the second lower frame is in abutment with the third cathode plate.

4. The fuel cell stack of claim 3, wherein The first membrane assembly comprises, from top to bottom, a first carbon paper, a first proton membrane, and a second carbon paper; the second membrane assembly comprises, from top to bottom, a third carbon paper, a second proton membrane, and a fourth carbon paper.

5. The fuel cell stack of claim 4, wherein Second insulating frames are arranged between the first and second cathode plates and between the first and second anode plates; the second insulating frames are arranged at the edges of the first cathode plate and the first anode plate, or the second insulating frames are arranged at the edges of the second cathode plate and the second anode plate.

6. The fuel cell stack of claim 5, wherein First sealant lines are arranged on the first and second insulating frames; Second sealant lines are arranged between the first cathode plate and the first upper frame, between the third anode plate and the second upper frame, between the third cathode plate and the second lower frame, and between the second anode plate and the first lower frame; The edge is a region 3 mm-6 mm away from the boundary of the first cathode plate / the first anode plate / the second cathode plate / the second anode plate.

7. The fuel cell stack of claim 6, wherein Cooling liquid flow channels are arranged on the side of the first cathode plate close to the first upper frame, on the side of the second cathode plate close to the second insulating frame, and on the side of the third cathode plate close to the first insulating frame.

8. The fuel cell stack of claim 7, wherein Oxygen flow channels are arranged on the side of the first cathode plate close to the first membrane assembly, on the side of the second cathode plate close to the second membrane assembly, and on the side of the third cathode plate close to the second lower frame.

9. The fuel cell stack of claim 8, wherein, The first anode plate is provided with a hydrogen gas flow channel on the side close to the first membrane assembly, the second anode plate is provided with a hydrogen gas flow channel on the side close to the second membrane assembly, and the third anode plate is provided with a hydrogen gas flow channel on the side close to the second upper frame.

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