CN115020738B

CN115020738B - Monopolar plate, bipolar plate and galvanic pile

Info

Publication number: CN115020738B
Application number: CN202210661791.7A
Authority: CN
Inventors: 王英; 刘冬安; 袁露; 贾古寨; 漆海龙
Original assignee: China Automotive Innovation Co Ltd
Current assignee: China Automotive Innovation Co Ltd
Priority date: 2022-06-13
Filing date: 2022-06-13
Publication date: 2024-02-23
Anticipated expiration: 2042-06-13
Also published as: CN115020738A

Abstract

The invention discloses a monopole plate, a bipolar plate and a galvanic pile, and belongs to the technical field of fuel cells. The invention relates to a unipolar plate, a bipolar plate and a galvanic pile, wherein the unipolar plate comprises a first plate body and a second plate body, the first plate body is provided with a first surface and a second surface which are opposite along a first direction, and the first surface is provided with a plurality of gas flow channels; the second plate body is provided with a third surface and a fourth surface which are opposite along the first direction, the fourth surface is provided with a plurality of cooling flow channels, the third surface is fixedly connected with the second surface, a closed accommodating groove is formed between the third surface and the second surface, and cooling liquid is arranged in the accommodating groove. The heat generated by the electrochemical reaction of reactants in the gas flow channel is transferred to the surface of the monopolar plate, so that the cooling liquid in the accommodating groove can be quickly evaporated to take away the heat, and the heat is transferred to the inside of the whole accommodating groove along with the diffusion of the evaporated cooling liquid, thereby having the effect of improving the heat distribution uniformity of the bipolar plate and avoiding local overheating; the cooling speed of the monopole plate can also be improved.

Description

Monopolar plate, bipolar plate and galvanic pile

Technical Field

The invention relates to the technical field of fuel cells, in particular to a monopolar plate, a bipolar plate and a galvanic pile.

Background

The proton exchange membrane fuel cell (Proton Exchange Membrane Fuel Cell, PEMFC) is an energy conversion device, has the advantages of high energy conversion efficiency, zero emission, no noise and the like, and can promote the development and the upgrading of technical systems such as hydrogen preparation, storage, transportation and the like by corresponding technical progress.

The proton exchange membrane fuel cell is formed by connecting a plurality of groups of single cells in series, and each group of single cell core components comprises a membrane electrode and a bipolar plate. Each membrane electrode assembly and bipolar plates (also referred to as flow field plates or diaphragm plates) disposed on both sides together constitute a single cell unit. The bipolar plate in the hydrogen fuel cell is also called a flow field plate, plays a role of separating an oxidant, a reducing agent and a coolant, uniformly distributes reactants (commonly used as hydrogen and oxygen) from an inlet of a common pipeline to all positions of each cell electrode in the electric pile through a flow channel, and gathers the reactants to an outlet of the common pipeline. Therefore, the bipolar plate needs to meet the requirements of high electrical conductivity, high thermal conductivity, good gas compactness, excellent mechanical and corrosion resistance and the like.

The bipolar plate has important influence on a plurality of parameters such as current density, volume/mass power density, cost, service life and the like of the fuel cell, is one of core components of the bipolar plate, and is one of important factors for determining the commercial application process of the fuel cell.

In the working process of the fuel cell, hydrogen enters the bipolar plate through the hydrogen inlet manifold, is distributed into the hydrogen flow field through the bipolar plate and is diffused into the gas diffusion layer, so that the hydrogen reaches the surface of the anode catalytic electrode, then hydrogen ions penetrate through the proton membrane to reach the surface of the cathode catalytic electrode, and electrons penetrate through the bipolar plate to reach the cathode of the adjacent single cell; the same oxidant enters the bipolar plate through the air inlet header pipe and is distributed into the air flow field through the bipolar plate, so that the oxidant reaches the surface of the cathode catalytic electrode to perform electrochemical reaction, huge heat can be generated in the reaction process, and the coolant flows in the middle of the bipolar plate to timely take away the heat generated by the electrochemical reaction.

The heat dissipation design of the bipolar plate of the fuel cell directly affects the fluid distribution of fuel gas and oxidant and water and thermal management of the fuel cell, thereby directly affecting the working efficiency and service life of the fuel cell. The heat generated by the electrochemical reaction can be taken away in time through the design optimization of the bipolar plate flow field, so that the efficiency of the fuel cell is improved.

The current bipolar plates are mainly divided into three types, namely graphite bipolar plates, composite bipolar plates and metal bipolar plates. The metal bipolar plate has the advantages of thin thickness, excellent conductivity, high mechanical strength and good gas isolation, is favorable for improving the specific power density of the battery, has mature processing technology of the metal material, is easy to realize the quantitative production of the polar plate, and becomes a main stream bipolar plate material of the hydrogen fuel battery.

In order to make the chemical reaction of fuel more sufficient, the metal bipolar plate is designed with a more complex flow channel structure, and tens or even hundreds of fine grooves are distributed on each unipolar plate forming the bipolar plate, so that a large amount of heat is generated when the electrochemical reaction occurs. If this heat cannot be taken away in time, it will cause the stack to be at risk of overheating, which not only affects the performance of the fuel cell, but also presents a safety hazard, and therefore the bipolar plates are typically cooled by the circulating coolant.

However, the heat generated by the electrochemical reaction is not completely uniform at different parts of the bipolar plate due to the influence of factors such as reactant concentration, so that the bipolar plate has a local overheating problem, and the performance and reliability of the electric pile are still affected. In order to solve the problem, in the prior art, the heat dissipation efficiency of the bipolar plate is improved by controlling the flow of the cooling liquid, so that not only is the energy consumption high, but also the problem of local overheating of the bipolar plate is not fundamentally solved by design.

Disclosure of Invention

A first object of the present invention is to provide a unipolar plate, which can improve the uniformity of the heat distribution of the bipolar plate and avoid the occurrence of local overheating problems.

A second object of the present invention is to provide a bipolar plate, which improves the uniformity of heat distribution of the bipolar plate and can avoid the occurrence of local overheating problems by applying the above-mentioned unipolar plate.

A third object of the present invention is to provide a stack, which has improved reliability by applying the bipolar plate.

In order to achieve the above object, the following technical scheme is provided:

in one aspect, there is provided a monopole plate comprising:

the first plate body is provided with a first surface and a second surface which are opposite along a first direction, and the first surface is provided with a plurality of gas flow channels;

the second plate body, the second plate body has along the relative third surface of first direction and fourth surface, the fourth surface is equipped with a plurality of cooling flow channels, the third surface with second surface fixed connection, just the third surface with be formed with confined holding tank between the second surface, be equipped with the coolant liquid in the holding tank.

As an alternative to the unipolar plate, the unipolar plate further includes a water absorbing member disposed within the receiving slot.

As an alternative to the unipolar plate, the water absorbing member is a water absorbing mesh.

As an alternative of the unipolar plate, the accommodating groove has a first groove wall and a second groove wall opposite along the first direction, the second groove wall is provided with a plurality of protrusions, one side of the water absorbing member is abutted with the first groove wall, and the other side is abutted with the protrusions.

As an alternative to the unipolar plate, the protrusions are provided on the second plate body.

As an alternative scheme of the unipolar plate, the accommodating groove is arranged on the second surface or the third surface; or alternatively, the first and second heat exchangers may be,

the holding groove includes first cell body and the second cell body of intercommunication each other, first cell body set up in the second surface, the second cell body set up in the third surface.

As an alternative to the unipolar plate, the plurality of gas flow channels are each located within a projection of the receiving groove along the first direction on the first surface.

As an alternative of the unipolar plate, the length of the cooling flow channel is not less than the length of the accommodating groove along the second direction; the second direction is perpendicular to the first direction.

As an alternative to a unipolar plate, the unipolar plate has a first end and a second end opposite in a third direction; the third direction is perpendicular to the first direction and the second direction in pairs;

the space between the cooling flow channel at the first end and the end part of the first end is a1, and the space between the accommodating groove and the end part of the first end is b1, so that a1 is less than or equal to b1; and/or the number of the groups of groups,

the distance between the cooling flow channel at the second end and the second end is a2, and the distance between the accommodating groove and the second end is b2, wherein a2 is less than or equal to b2.

In a second aspect, a bipolar plate is provided, comprising two unipolar plates as described above, the fourth surfaces of the two unipolar plates being fixedly connected.

In a third aspect, there is provided a stack comprising a bipolar plate as described above.

Compared with the prior art, the invention has the beneficial effects that:

according to the unipolar plate and the bipolar plate, heat generated by electrochemical reaction of reactants in the gas flow channel is transferred to the surface of the unipolar plate, so that the local or whole temperature of the unipolar plate is increased, cooling liquid in the accommodating groove can be rapidly evaporated to take away the heat, and the heat is transferred to the inside of the whole accommodating groove along with the diffusion of the evaporated cooling liquid, so that the effect of improving the heat distribution uniformity of the bipolar plate is achieved, and local overheating is avoided; meanwhile, the evaporated cooling liquid can form liquid again under the action of the cooling liquid flowing in the cooling flow channel, in other words, the heat is taken away by the cooling liquid flowing in the cooling flow channel, and the circulation is performed, so that the purpose of cooling the monopole plate is achieved, the problem of local overheating of the monopole plate can be avoided, the cooling speed of the monopole plate can be improved, and the performance and the reliability of the fuel cell can be improved.

The galvanic pile of the invention comprises the bipolar plate. By applying the bipolar plate, the reliability of the electric pile can be improved.

Drawings

FIG. 1 is an exploded view of a unipolar plate in an embodiment of the present invention;

FIG. 2 is an assembly view of a first plate and a water absorbing member according to an embodiment of the present invention;

FIG. 3 is a schematic view of a unipolar plate according to an embodiment of the present invention;

FIG. 4 is a cross-sectional view of the A-A plane of FIG. 3;

fig. 5 is an enlarged view of a portion B of fig. 4;

FIG. 6 is a schematic structural diagram of a first plate according to an embodiment of the present invention;

FIG. 7 is a second schematic structural view of the first plate according to the embodiment of the present invention;

FIG. 8 is a schematic diagram of a second plate according to an embodiment of the present invention;

fig. 9 is a schematic diagram of a second plate according to an embodiment of the invention.

Reference numerals:

100. a unipolar plate; 101. a first end; 102. a second end;

1. a first plate body; 11. a first surface; 12. a second surface; 13. a gas flow passage;

2. a second plate body; 21. a third surface; 22. a fourth surface; 23. a cooling flow passage;

3. a receiving groove; 31. a first groove wall; 32. a second groove wall; 33. a protrusion; 34. a first tank body; 35. a second tank body;

4. a water absorbing member.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.

In the description of the present invention, it should be noted that, directions or positional relationships indicated by terms such as "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., are directions or positional relationships based on those shown in the drawings, or are directions or positional relationships conventionally put in use of the inventive product, are merely for convenience of describing the present invention and simplifying the description, and are not indicative or implying that the apparatus or element to be referred to must have a specific direction, be configured and operated in a specific direction, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and should not be construed as indicating or implying relative importance. In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.

In the description of the present invention, it should also be noted that, unless explicitly specified and limited otherwise, the terms "disposed", "connected" and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected or integrally connected; either mechanically or electrically. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

In the present invention, unless expressly stated or limited otherwise, a first feature "above" or "below" a second feature may include both the first and second features being in direct contact, as well as the first and second features not being in direct contact but being in contact with each other through additional features therebetween. Moreover, a first feature being "above," "over" and "on" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicating that the first feature is higher in level than the second feature. The first feature being "under", "below" and "beneath" the second feature includes the first feature being directly under and obliquely below the second feature, or simply means that the first feature is less level than the second feature.

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the invention.

As shown in fig. 1-9, the present embodiment provides a unipolar plate and a bipolar plate, the bipolar plate comprising two fixedly connected unipolar plates 100, it being understood that one unipolar plate 100 serves as an anode plate and the other unipolar plate 100 serves as a cathode plate.

In the working process of the fuel cell, reactants perform electrochemical reaction on the surface of the bipolar plate, and huge heat is generated in the reaction process; in addition, the heat generated by the electrochemical reaction is not completely uniform at different parts of the bipolar plate due to factors such as reactant concentration, and thus, the bipolar plate has a problem of local overheating.

In the prior art, the flow of circulating cooling water is controlled, so that the bipolar plate can be well cooled, but the mode has high energy consumption, and the problem of local overheating of the bipolar plate cannot be fundamentally solved by design.

To solve the above-described problems, in the present embodiment, as shown in fig. 1 to 5, a monopolar plate 100 includes a first plate body 1 and a second plate body 2, the first plate body 1 having a first surface 11 and a second surface 12 opposite to each other in a first direction, the first surface 11 being provided with a plurality of gas flow passages 13; the second plate body 2 is provided with a third surface 21 and a fourth surface 22 which are opposite along the first direction, the fourth surface 22 is provided with a plurality of cooling flow channels 23, the third surface 21 is fixedly connected with the second surface 12, a closed accommodating groove 3 is formed between the third surface 21 and the second surface 12, and cooling liquid is arranged in the accommodating groove 3.

The heat generated by the electrochemical reaction of the reactants in the gas flow channel 13 is transferred to the surface of the unipolar plate 100, so that the local or whole temperature of the unipolar plate 100 is raised, the cooling liquid in the accommodating groove 3 can be quickly evaporated to take away the heat, and the heat is transferred to the inside of the whole accommodating groove 3 along with the diffusion of the evaporated cooling liquid, so that the bipolar plate has the effect of improving the heat distribution uniformity of the bipolar plate and avoiding local overheating; meanwhile, the evaporated cooling liquid can form liquid again under the action of the cooling liquid flowing in the cooling flow channel 23, in other words, the cooling liquid flowing in the cooling flow channel 23 is utilized to take away heat, and the circulation is performed, so that the purpose of cooling the unipolar plate 100 is achieved, the problem of local overheating of the unipolar plate 100 can be avoided, the cooling speed of the unipolar plate 100 can be improved, and the performance and reliability of the fuel cell can be improved.

In the bipolar plate provided in this embodiment, the fourth surfaces 22 of the two unipolar plates 100 are fixedly connected. For example, the fourth surfaces 22 of the two unipolar plates 100 may be fixedly connected by welding or bonding. In other words, the bipolar plate of the embodiment still adopts the common runner design in the prior art, is stacked with the membrane electrode assembly in the traditional way, can be manufactured into a galvanic pile by adopting original equipment and technology, has low transformation cost, and is suitable for popularization.

Alternatively, in the unipolar plate 100, the third surface 21 and the second surface 12 may be fixedly coupled by laser welding, brazing, argon arc welding, resistance welding, diffusion welding, or the like.

Alternatively, the cooling liquid in the accommodating tank 3 may be water, one of organic matters such as ethanol, glycol, and methanol, or a mixture of any two or more of organic matters such as ethanol, glycol, and methanol.

It will be appreciated that the gas flow channels 13 are used for conveying reactants, and local overheating problems are more likely to occur in the gas flow channels 13 when electrochemical reaction occurs, and optionally, a plurality of gas flow channels 13 are all located in the projection range of the accommodating groove 3 on the first surface 11 along the first direction, so that the local overheating parts can be cooled rapidly and sufficiently.

Alternatively, in the second direction, the length of the cooling flow passage 23 is not smaller than the length of the accommodating groove 3. Further, for convenience of description, opposite ends of the unipolar plate 100 in the third direction are respectively denoted as a first end 101 and a second end 102; the third direction is perpendicular to the first direction and the second direction. Alternatively, as shown in FIGS. 3 and 7, the cooling flow path 23 at the first end 101 is spaced a1 from the end of the first end 101, and the space between the accommodating groove 3 and the end of the first end 101 is b1, so that a 1. Ltoreq.b1; the space between the cooling flow channel 23 at the second end 102 and the end of the second end 102 is a2, and the space between the accommodating groove 3 and the end of the second end 102 is b2, a2 is less than or equal to b2. By the arrangement, the cooling liquid in the accommodating groove 3 can be cooled by fully utilizing the cooling liquid in the cooling flow channel 23, so that the cooling liquid in the accommodating groove 3 can ensure the uniformity of heat distribution of the unipolar plate 100.

In order to enable the cooling liquid in the accommodating groove 3 to be evaporated by contacting with the first plate body 1 to absorb heat and ensure that the evaporated cooling liquid can be diffused in the accommodating groove 3, and enable the cooling liquid to be contacted with the second plate body 2 to transfer heat to the cooling liquid in the cooling flow channel 23, the monopole plate 100 further comprises a water absorbing piece 4, and the water absorbing piece 4 is arranged in the accommodating groove 3. The water absorbing member 4 can keep the cooling liquid, so that the distribution uniformity of the cooling liquid can be improved, and the cooling effect can be improved.

Optionally, the water absorbing member 4 is a water absorbing net, which does not affect the diffusion of the evaporated cooling liquid in the accommodating groove 3, and is beneficial to improving the uniformity of heat distribution of the unipolar plate 100.

Illustratively, the water absorbing mesh is a copper mesh or a stainless steel mesh, which has good thermal conductivity and is beneficial to further improving the uniformity of heat distribution of the unipolar plate 100.

Alternatively, the shape of the receiving groove 3 may be circular or elliptical, and may also be rectangular, square, polygonal, or the like.

Alternatively, as shown in fig. 5, the accommodating groove 3 has a first groove wall 31 and a second groove wall 32 opposite in the first direction, the second groove wall 32 is provided with a plurality of projections 33, one side of the water absorbing member 4 abuts against the first groove wall 31, and the other side abuts against the projections 33. By the arrangement, the water absorbing member 4 can be supported and positioned, so that the problem that the water absorbing member 4 collapses or folds and deforms is avoided, and the water absorbing property of the water absorbing member 4 is further protected. In addition, the protrusion 33 may form a cavity between the water absorbing member 4 and the second groove wall 32, so as to accommodate the evaporated cooling liquid, and facilitate the diffusion of the evaporated cooling liquid along the cavity, thereby facilitating the rapid cooling and re-formation of the evaporated cooling liquid and promoting the circulation of the cooling liquid.

Alternatively, the protrusion 33 may have a cylindrical, conical or truncated cone-shaped structure, or may have a hexahedral or other polyhedral structure, so long as it can support the water absorbing member 4, which is not limited herein.

In the fuel cell, the reactants electrochemically react on the first surface 11 of the first plate 1, so that the temperature of the first plate 1 is relatively high, in order to improve the cooling effect on the first plate 1, to achieve the purpose of rapid heat transfer and rapid evaporation of the cooling liquid in the accommodating tank 3, in this embodiment, the protrusions 33 are disposed on the second plate 2, so that the water absorbing member 4 is supported by the protrusions 33, and the water absorbing member 4 is directly contacted with the first plate 1.

In this embodiment, as shown in fig. 7 and 9, the accommodating groove 3 includes a first groove 34 and a second groove 35 that are mutually communicated, the first groove 34 is opened on the second surface 12, and the second groove 35 is opened on the third surface 21. In other words, the first slot 34 and the second slot 35 are both open-ended, and the opening of the first slot 34 and the opening of the second slot 35 are opposite to each other, so as to form a closed accommodating slot 3 between the first plate 1 and the second plate 2. It can be understood that, so set up, on guaranteeing holding tank 3 volumetric basis, set up holding tank 3 into split type structure, can not make the thickness difference between first plate body 1 and the second plate body 2 too big to guarantee the intensity of first plate body 1 and second plate body 2, be difficult for appearing the problem such as deformation.

In other embodiments, the accommodating groove 3 may be further formed on the second surface 12 or the third surface 21, in other words, the accommodating groove 3 has an open structure at one end and is formed on one of the first plate body 1 and the second plate body 2, and the opening of the accommodating groove 3 is closed by using the other one of the two, so that only one grooving operation is required, and the process is simplified.

In this embodiment, the first plate body 1 and the second plate body 2 are both metal plates, and may be formed by press forming or chemical etching.

The embodiment also provides a galvanic pile comprising the bipolar plate. By applying the bipolar plate, the reliability of the electric pile can be improved.

Note that the above is only a preferred embodiment of the present invention and the technical principle applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, while the invention has been described in connection with the above embodiments, the invention is not limited to the embodiments, but may be embodied in many other equivalent forms without departing from the spirit or scope of the invention, which is set forth in the following claims.

Claims

1. A monopolar plate, comprising:

a first plate body (1), the first plate body (1) having a first surface (11) and a second surface (12) opposite in a first direction, the first surface (11) being provided with a plurality of gas flow channels (13);

the second plate body (2), the second plate body (2) is provided with a third surface (21) and a fourth surface (22) which are opposite along the first direction, the fourth surface (22) is provided with a plurality of cooling flow channels (23), the third surface (21) is fixedly connected with the second surface (12), a closed accommodating groove (3) is formed between the third surface (21) and the second surface (12), and cooling liquid is arranged in the accommodating groove (3);

the monopole board (100) further comprises a water absorbing piece (4), and the water absorbing piece (4) is arranged in the accommodating groove (3);

the accommodating groove (3) is provided with a first groove wall (31) and a second groove wall (32) which are opposite along the first direction, the second groove wall (32) is provided with a plurality of bulges (33), one side of the water absorbing piece (4) is abutted with the first groove wall (31), and the other side is abutted with the bulges (33);

the protrusion (33) is arranged on the second plate body (2).

2. The unipolar plate according to claim 1, characterized in that the water-absorbing element (4) is a water-absorbing mesh.

3. The unipolar plate according to claim 1, characterized in that the receiving groove (3) is open at the second surface (12) or the third surface (21); or alternatively, the first and second heat exchangers may be,

the accommodating groove (3) comprises a first groove body (34) and a second groove body (35) which are mutually communicated, the first groove body (34) is arranged on the second surface (12), and the second groove body (35) is arranged on the third surface (21).

4. A unipolar plate according to claim 1, characterized in that a number of the gas flow channels (13) are each located within the projection of the receiving groove (3) onto the first surface (11) along the first direction.

5. The unipolar plate according to claim 1, characterized in that, in the second direction, the length of the cooling flow channel (23) is not less than the length of the containing groove (3); the second direction is perpendicular to the first direction.

6. The unipolar plate of claim 5, wherein the unipolar plate (100) has a first end (101) and a second end (102) opposite in a third direction; the third direction is perpendicular to the first direction and the second direction in pairs;

the space between the cooling flow channel (23) at the first end (101) and the end part of the first end (101) is a1, and the space between the accommodating groove (3) and the end part of the first end (101) is b1, so that a1 is less than or equal to b1; and/or the number of the groups of groups,

the distance between the cooling flow channel (23) positioned at the second end (102) and the end part of the second end (102) is a2, and the distance between the accommodating groove (3) and the end part of the second end (102) is b2, so that a2 is less than or equal to b2.

7. Bipolar plate, characterized in that it comprises two monopolar plates (100) according to any of claims 1-6, said fourth surfaces (22) of two of said monopolar plates (100) being fixedly connected.

8. A stack comprising the bipolar plate of claim 7.