CN115642272A - A bipolar plate, open-cathode fuel cell stack with external cooling fins - Google Patents

Abstract

The invention provides a bipolar plate with external radiating fins and a cathode open type fuel cell stack, wherein the bipolar plate comprises a flow field plate and radiating fin plates, and the radiating fin plates are arranged at the upper end, the lower end or the upper end and the lower end of the flow field plate to release heat transferred by the flow field plate; the fuel cell pile comprises a pile core formed by repeatedly stacking the bipolar plates and the membrane electrodes, and end plates, insulating plates and current collecting plates which are sequentially and symmetrically arranged on two sides of the pile core from outside to inside; the cathode flow channels of the flow field plates in the bipolar plates are in direct communication with the external environment. Compared with a fuel cell stack without an external radiating fin plate, the fuel cell stack has more radiating ways and a larger radiating area, reduces the air flow rate required by heat radiation under the same radiating capacity, reduces the parasitic energy consumption, meets the radiating requirement of the stack when the stack operates under higher current density under the same parasitic power, and improves the output power of the stack.

Description

A bipolar plate, open-cathode fuel cell stack with external cooling fins

technical field

The invention belongs to the technical field of fuel cells and heat management, and in particular relates to a bipolar plate with external cooling fins and an open-cathode fuel cell stack.

Background technique

Fuel cells are considered as a new type of energy conversion technology, which can convert the chemical energy stored in the fuel into electrical energy and heat energy through electrochemical reactions, and have the advantages of high energy conversion efficiency, zero emissions, low operating noise, and low maintenance costs. Fuel cells will continue to generate heat during power generation, so thermal management is required to maintain a stable operating temperature of the stack.

In order to reduce the volume, mass and complexity of the system, in small fuel cell stacks, air cooling is often used to cool the stack. The cathode open stack is a kind of air-cooled stack, and its cathode flow channel is not only a reaction gas channel, but also a cooling flow channel. However, due to the small specific heat of air, the air flow required for heat dissipation is large. When a large flow of air passes through the cathode flow channel, a large flow resistance is generated, which increases the parasitic energy consumption of the stack. The large flow of air may also cause insufficient proton conductors in the proton exchange membrane, affecting proton transport, and further affecting the output performance and service life of the fuel cell.

In addition, as the operating temperature of the fuel cell stack increases and the number of cells increases, the temperature difference between different positions inside the stack gradually increases, and a large amount of heat is concentrated in the center of the stack, resulting in a change in the uniformity of temperature distribution among the stack cells. Poor, affecting the reliability, stability and durability of the stack.

Contents of the invention

In order to overcome the deficiencies in the prior art, the inventors have carried out dedicated research and provided a bipolar plate with external cooling fins and an open-cathode fuel cell stack to solve the parasitic problems of the current open-cathode air-cooled fuel cell stack. The problems of large energy consumption and uneven temperature distribution among monomers.

The technical scheme provided by the invention is as follows:

In the first aspect, a bipolar plate with external heat dissipation fins, the bipolar plate includes a flow field plate and a heat dissipation fin plate, and the heat dissipation fin plate is arranged at the upper end, the lower end or the upper and lower ends of the flow field plate, Release the heat transferred by the flow field plate.

In the second aspect, an open-cathode fuel cell stack with external cooling fins includes a stack core formed by repeated stacking of bipolar plates and membrane electrodes, and is symmetrically installed on both sides of the stack core sequentially from outside to inside. Side end plates, insulating plates and collector plates;

The bipolar plate includes a flow field plate and a heat dissipation fin plate, and the cathode flow channel of the flow field plate is directly connected with the external environment; The heat transferred by the flow field plate;

The end plate is used to cooperate with the fastener to control the contact pressure between the components of the fuel cell stack;

The insulating plate is used for electrical isolation of the current collecting plate and the end plate;

The collector plate is used to transmit the electric energy of the fuel cell stack to an external load.

A cathode open fuel cell stack with external cooling fins provided by the present invention has the following beneficial effects:

(1) The present invention provides a cathode open fuel cell stack with external cooling fins. The external cooling fin plate increases the heat dissipation path and heat dissipation area of the fuel cell stack. Under the same heat dissipation, it can Reducing the flow rate of air required for heat dissipation not only avoids performance and life problems caused by insufficient proton conductors in the proton exchange membrane, but also reduces air flow resistance and parasitic energy consumption;

(2) The present invention provides a cathode open fuel cell stack with external heat dissipation fins. The external heat dissipation fin plate increases the heat dissipation capacity of the fuel cell stack. Under the same parasitic power, the stack meets the requirements of Heat dissipation requirements during operation at higher current densities, increasing the output power of the stack;

(3) In the open-cathode fuel cell stack with external heat dissipation fins provided by the present invention, the closer to the center of the stack, the larger the heat dissipation area of the fin plate, which can avoid the heat concentration in the center of the stack, and the temperature distribution is high in the middle. The problem of low ends increases the uniformity of temperature distribution among the cells of the stack, thereby improving the reliability, stability and durability of the fuel cell stack.

Description of drawings

Fig. 1 is a schematic structural view of a flow field plate with external cooling fins of the present invention;

Fig. 2 is a schematic structural view of an open-cathode fuel cell stack with external cooling fins according to the present invention.

Explanation of reference numbers

1-end plate, 2-insulation plate, 3-collector plate, 4-bipolar plate, 41-flow field plate, 42-radiating fin plate, 5-membrane electrode, 6-fan.

Detailed ways

The following describes the present invention in detail, and the features and advantages of the present invention will become more clear and definite along with these descriptions.

The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior or better than other embodiments. While various aspects of the embodiments are shown in drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

The present invention provides a bipolar plate with external cooling fins, as shown in Figure 1, the bipolar plate includes a flow field plate 41 and a heat dissipation fin plate 42, and the heat dissipation fin plate 42 is arranged The upper end, the lower end or the upper and lower ends of the plate 41 release the heat transferred by the flow field plate.

In a preferred embodiment, the heat dissipation fin plate 42 is an extension of the flow field plate 41 and is integrally processed with the flow field plate 41 .

In a preferred embodiment, the bipolar plate is made of high thermal conductivity materials, such as graphite, gold-plated metal, etc., with thermal conductivity ≥ 100W/(m·K), and conducts the heat generated by the fuel cell to the external heat dissipation fins plate 42.

In a preferred embodiment, the heat dissipation area of the heat dissipation fin plate varies with the distance between the bipolar plate and the center of the electric stack, and the closer the heat dissipation area of the heat dissipation fin plate on the bipolar plate to the center of the electric stack is bigger. The heat dissipation area of the heat dissipation fin plate can be realized by changing the number of fins on the heat dissipation fin plate, the shape of the fins and the height of the fins. The shape of the fins on the heat dissipation fin plate includes but not limited to straight fins, louver fins, serrated fins and corrugated fins.

The present invention also provides a cathode open fuel cell stack with external cooling fins, as shown in Figure 1 and Figure 2, comprising a stack core formed by stacking bipolar plates 4 and membrane electrodes 5 repeatedly and consisting of The end plate 1, the insulating plate 2 and the collector plate 3 are symmetrically installed on both sides of the stack core from outside to inside;

The bipolar plate 4 includes a flow field plate 41 and a heat dissipation fin plate 42. The cathode flow channel of the flow field plate 41 is directly connected with the external environment, taking into account the functions of providing cathode reactants and cooling the stack; the heat dissipation The finned plate 42 is arranged on the upper end, the lower end or the upper and lower ends of the flow field plate 41 to release the heat transferred by the flow field plate;

The heat dissipation area of the heat dissipation fin plate 42 on the flow field plate 41 is sufficient to keep the temperature difference inside the stack within a specified range, such as within ±2°C.

The end plate 1 is used to cooperate with fasteners to control the contact pressure between the components of the fuel cell stack;

The insulating plate 2 is used for electrical isolation of the current collecting plate 3 and the end plate 1;

The collector plate 3 is used to transmit the electric energy of the fuel cell stack to an external load.

Example 1

As shown in Figures 1 and 2, an open-cathode fuel cell stack with external cooling fins includes an end plate 1, an insulating plate 2, a current collector plate 3, a bipolar plate 4 and a membrane electrode 5, and an external fan 6 Fixed on the side of the fuel cell stack, it is used to provide cathode reactant and stack cooling gas.

The bipolar plate 4 includes a flow field plate 41 and a heat dissipation fin plate 42, the heat dissipation fin plates 42 are distributed on the upper and lower sides of the flow field plate of the fuel cell stack, and the space between adjacent heat dissipation fin plates 42 forms a heat dissipation chamber. The heat dissipation area of the heat dissipation fin plate 42 varies with the distance from the center of the electric stack, and the closer to the center of the electric stack, the larger the heat dissipation area of the heat dissipation fin plate 42 . The change of the heat dissipation area can be realized by changing the number of fins on the heat dissipation fin plate 42 , the shape of the fins and the height of the fins. In this embodiment, the number of fins is changed by changing the overall height of the fin plate, thereby changing the heat dissipation area. The height of the fin plate at the center of the stack is 20 mm, and the fin structure adopts straight fins. The width of a single fin and The heights are all 1mm. In the specific application process, the number of fins or the height of a single fin can be changed according to the heat dissipation requirements, and the fin structure can also be designed as louver fins, sawtooth fins, and corrugated fins.

When the fuel cell stack is running, the fan 6 is turned on to send a certain flow of air into the heat dissipation chamber between the cathode channel of the flow field plate 41 and the heat dissipation fin plate 42 . The air acts as both the cathode reactant and the cooling medium in the cathode channel of the flow field plate 41 , and only serves as the cooling medium in the heat dissipation chamber between the heat dissipation fin plates 42 . The heat generated by the fuel cell stack is mainly dissipated in two ways. The first way is that after the heat is generated at the reaction site, it is conducted to the gas diffusion layer of the membrane electrode 5 and the flow field plate 41, and forms forced convection with the air sent in by the fan 6 in the cathode flow field, and the heat is converted into air The internal energy is carried away from the stack with the air flow. The second approach is that after the heat is conducted to the flow field plate 41, it continues to be conducted to the heat dissipation fin plate 42 through the high thermal conductivity material of the bipolar plate 6, and forms with the air sent in by the fan 6 in the heat dissipation chamber between the plates. Forced convection, the heat is also converted into the internal energy of the air and is taken away from the stack with the air flow. In addition, a small amount of heat is discharged into the environment through radiation and natural convection, which together with the above two main ways maintain the stability of the operating temperature of the fuel cell stack.

The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions should not be construed as limiting the present invention. Those skilled in the art understand that without departing from the spirit and scope of the present invention, various equivalent replacements, modifications or improvements can be made to the technical solutions and implementations of the present invention, all of which fall within the scope of the present invention. The protection scope of the present invention shall be determined by the appended claims.

The content that is not described in detail in the description of the present invention belongs to the well-known technology of those skilled in the art.

Claims (8)

1. a bipolar plate with external heat dissipation fins, it is characterized in that, described bipolar plate comprises flow field plate (41) and heat dissipation fin plate (42), and described heat dissipation fin plate (42) is arranged on The upper end, the lower end or the upper and lower ends of the flow field plate (41) release the heat transferred by the flow field plate. 2. The bipolar plate with external heat dissipation fins according to claim 1, characterized in that, the heat dissipation fin plate (42) is used as an extension of the flow field plate (41), and is connected with the flow field plate (41) Processed in one piece. 3. The bipolar plate with external heat dissipation fins according to claim 1, characterized in that, the heat dissipation area of the heat dissipation fin plate (42) varies with the distance from the center of the stack to the bipolar plate. The heat dissipation area of the heat dissipation fin plate on the bipolar plate near the center of the stack is larger. 4. The bipolar plate with external heat dissipation fins according to claim 1, characterized in that, the heat dissipation area of the heat dissipation fin plate (42) is changed by changing the number of fins and the shape of the fins on the heat dissipation fin plate. and fin heights are achieved. 5. The bipolar plate with external heat dissipation fins according to claim 1, characterized in that, the shape of the fins on the heat dissipation fin plate (42) is straight fins, louver fins, sawtooth fins or corrugated fins. 6 . The bipolar plate with external cooling fins according to claim 1 , wherein the thermal conductivity of the bipolar plate is ≥100 W/(m·K). 7. An open-cathode fuel cell stack with external heat dissipation fins, characterized in that it comprises a bipolar plate (4) and a membrane electrode (5) repeatedly stacked according to any one of claims 1 to 6. The electric stack core, and the end plates (1), insulating plates (2) and current collector plates (3) installed symmetrically on both sides of the electric stack core in sequence from the outside to the inside; The cathode channel of the flow field plate (41) on the bipolar plate (4) is directly connected with the external environment; The end plate (1) is used to cooperate with the fastener to control the contact pressure between the components of the fuel cell stack; The insulating plate (2) is used for electrical isolation of the current collecting plate (3) and the end plate (1); The collector plate (3) is used to transmit the electric energy of the fuel cell stack to an external load. 8. The cathode open fuel cell stack with external heat dissipation fins according to claim 7, characterized in that, the heat dissipation area of the heat dissipation fin plate (42) on the bipolar plate (4) satisfies the requirement that the stack The internal temperature difference is within the specified range.

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