CN211320215U

CN211320215U - Fuel cell stack

Info

Publication number: CN211320215U
Application number: CN202020286245.6U
Authority: CN
Inventors: 宋文帅; 王宗田; 涂蒙; 霍茂森; 张土旺; 蒋帅; 张娟; 方晓博; 王昊; 牛永凯
Original assignee: Fenghyang Technology Hangzhou Co ltd
Current assignee: Wind hydrogen Yang hydrogen energy technology (Shanghai) Co.,Ltd.
Priority date: 2020-03-10
Filing date: 2020-03-10
Publication date: 2020-08-21
Anticipated expiration: 2030-03-10

Abstract

The utility model discloses a fuel cell stack, a serial communication port, include: the electric pile tail end plate (11) is positioned at the tail end, and the electric pile air inlet end plate (12) is positioned at the air inlet end; a current collecting plate (21) close to the electric pile gas inlet end plate (12) and used for collecting electric energy; the bipolar plate is positioned between the end plate (11) of the electric pile and the gas inlet end plate (12) of the electric pile, and a flexible resistance plate (61) used for heating the current collecting plate (21) is arranged between a first polar plate (51) of the bipolar plate, which is close to the current collecting plate (21), and the current collecting plate (21). The flexible resistance plate is added between the first polar plate and the current collecting plate of the existing fuel cell stack, so that heat can be generated when current passes through the flexible resistance plate to heat the first polar plate, the temperature of the first polar plate is ensured to be the same as or slightly higher than that of the monocells in the stack, and the service life of the stack is prolonged.

Description

Fuel cell stack

Technical Field

The utility model belongs to the technical field of fuel cell's technique and specifically relates to a fuel cell stack.

Background

A fuel cell is an energy conversion device that can directly convert chemical energy in fuel (hydrogen gas) into electrical energy and generate byproducts such as heat, water, and the like. Since there are no other conversion steps in the conversion process, the energy conversion efficiency of the fuel cell is much higher than that of other energy conversion devices, such as a fuel engine. The proton exchange membrane fuel cell is one of fuel cells, the operating temperature is 60-80 ℃, and the proton exchange membrane fuel cell has been developed after the technology of the proton exchange membrane fuel cell has been broken through at the end of the last century. Because of their high efficiency and high power density, and because of their lack of pollutant emissions during operation, pem fuel cells are considered as a replacement for fuel-powered engines. The fuel cell hereinafter refers specifically to a proton exchange membrane fuel cell.

The fuel cell stack is a place where energy conversion of fuel occurs, and with the development of technology, the performance of the fuel cell stack is gradually improved, and the service life of the fuel cell stack is also greatly improved. In order to replace the fuel engine, the performance of the fuel cell needs to be further improved, and the service life of the fuel cell needs to be greatly improved. The performance and the service life of the fuel cell are influenced by the internal temperature, the pressure, the gas flow, the reactant concentration and the like of the stack, and the improvement of the operating temperature, the input gas pressure and the reactant concentration of the fuel cell are beneficial to the improvement of the performance of the stack. The lifetime of the fuel cell stack is influenced by various factors, such as the voltage uniformity of each single cell, the number of times of turning on and off the fuel cell stack, impurities in the fuel gas, impurities in the air, and the like.

One of the major problems facing current fuel cell stacks is the end effect of the fuel cell stack: the cell voltage at the end of the fuel cell stack closest to the gas outlet is generally lower than the cell voltage inside the stack. The reason for this problem is various, for example, the heat dissipation from the interior of the fuel cell stack is slow due to the temperature, and the heat dissipation is mainly performed by the coolant, and the temperature is high relative to the unit cell whose end portion can radiate heat outward. At different temperatures, there is a difference in the performance of the fuel cell, which is manifested by the end of the stack near the exhaust port having a voltage significantly lower than the cell voltage inside the stack.

As the fuel cell stack operates, the stack performance degrades, and the cells at the ends of the stack will quickly fail, resulting in a much shorter life than other higher performance fuel cells. Thus, the end effect can severely impact the life of the fuel cell stack.

Therefore, how to provide a fuel cell stack to improve the service life of the fuel cell stack is a technical problem to be solved in the field.

SUMMERY OF THE UTILITY MODEL

In view of the above, the present invention provides a fuel cell stack, which can improve the service life of the fuel cell stack.

In order to achieve the above object, the utility model provides a following technical scheme:

a fuel cell stack, comprising:

the electric pile tail end plate is positioned at the tail end, and the electric pile air inlet end plate is positioned at the air inlet end;

the collector plate is close to the electric pile air inlet end plate and used for collecting electric energy;

and a flexible resistance plate for heating the collector plate is arranged between a first polar plate close to the collector plate in the bipolar plate and the collector plate.

Preferably, in the fuel cell stack, the flexible resistor plate is hermetically connected to the collector plate.

Preferably, in the fuel cell stack, a groove for accommodating the flexible resistor plate is formed on a surface of the first electrode plate opposite to the collector plate.

Preferably, in the fuel cell stack, a depth of the groove is smaller than a thickness of the flexible resistor plate after the flexible resistor plate is compressed to the maximum.

Preferably, in the fuel cell stack, the groove is formed in the first electrode plate.

Preferably, in the fuel cell stack, a sealing ring member is hermetically attached to a surface of the first electrode plate opposite to the current collecting plate, and the sealing ring member forms a receiving groove for receiving the flexible resistor plate.

Preferably, in the fuel cell stack, the flexible resistor plate and the first electrode plate have the same shape and size of the coolant flow field.

Preferably, in the fuel cell stack, the flexible resistor plate is a carbon paper plate or a carbon cloth plate having a resistor.

According to the above technical scheme, the utility model discloses a fuel cell increases the flexible resistance board between the first polar plate of current fuel cell stack and collector, can produce the heat when the electric current passes through this flexible resistance board, heats first polar plate, guarantees that the temperature of first polar plate is the same with the temperature of the inside monocell of pile, perhaps surpasss the temperature of inside monocell a little to the life-span of extension pile.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art are briefly introduced below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 is a schematic structural view of the fuel cell plate disclosed in the embodiment of the present invention after disassembly.

Detailed Description

In view of this, the core of the present invention is to disclose a fuel cell stack, which can improve the service life of the fuel cell stack.

In order to make the technical field better understand the solution of the present invention, the following detailed description of the present invention is provided with reference to the accompanying drawings and the detailed description.

As shown in fig. 1, the present invention discloses a fuel cell, comprising: stack end plate 11, stack inlet end plate 12, collector plate 21, bipolar plate, and flexible resistor plate 61. Wherein, the end plate 11 at the end of the fuel cell stack is positioned at the end of the fuel cell stack, and the inlet end plate 12 of the fuel cell stack is positioned at the inlet end of the fuel cell stack; the collector plate 21 is close to the air inlet end plate of the pile, and is used for collecting the generated electric energy and conducting the electric energy to an external circuit; the bipolar plate is positioned between the stack tail end plate 11 and the stack inlet end plate 12, and a flexible resistance plate 61 for heating the current collecting plate 21 is arranged between the first polar plate 51 of the bipolar plate close to the current collecting plate 21 and the current collecting plate 21. The bipolar plate in this application is the same as the mainstream bipolar plate structure in the market at present, is used for distributing fuel gas and air on both sides of the polar plate, and contains the coolant flow field in the inside for taking the heat generated inside the fuel cell stack out of the stack. In addition, a sealing ring 41 is disposed between the bipolar plate and the membrane electrode 42 for sealing the space between the bipolar plate and the membrane electrode 42 and preventing the reactant gas from leaking to the outside of the fuel cell stack, and the sealing ring 41 is required to be used on both sides of the membrane electrode 42. Specifically, the membrane electrode 42 is the primary site where electrochemical reactions within the fuel cell stack occur, and is used to output electrical energy.

The core of the present application is to add a flexible resistance plate 61 between the first electrode plate 51 and the current collecting plate 21 of the existing fuel cell stack, so that heat can be generated when current passes through the flexible resistance plate 61 to heat the first electrode plate 51, thereby ensuring that the temperature of the first electrode plate 51 is the same as or exceeds the temperature of the single cells inside the stack, and prolonging the service life of the stack.

The flexible resistive plate 61 in this application is sealingly connected to the collector plate 21. In practice, the flexible resistive sheet 61 may be hermetically connected to the first electrode sheet 51. The specific installation position of the flexible resistance plate 61 can be set according to different requirements and is within the protection range.

In a preferred embodiment, the faces of the first polar plate 51 opposite to the current collecting plate 21 are provided with grooves for accommodating the flexible resistor plates 61. The flexible resistive sheet 61 is disposed in the groove, and the flexible resistive sheet 61 can be connected and positioned. In practice, the first electrode plate 51 and the current collecting plate 21 are preferably sealed by a sealing member, or coated and sealed by a sealing adhesive. The manner of attachment of the seal is not particularly limited herein.

Since the flexible resistive sheet 61 has a certain amount of compression during mounting, in order to ensure stable mounting of the flexible resistive sheet 61, the depth of the groove is set to be less than the thickness of the flexible resistive sheet 61 after the maximum amount of compression, that is, the flexible resistive sheet 61 can contact the first polar plate 51 and the current collecting plate 21 after the flexible resistive sheet 61 is press-mounted. Preferably, the depth of the groove may be set to about 50% of the thickness of the flexible resistive sheet 61. In practice, the thickness of the required recess can also be adjusted by means of the sealing ring element, i.e. the above-mentioned recess is formed by means of the sealing ring element and is provided as an elastic element.

In practice, the groove may be formed on the first electrode plate 51, and the flexible resistor plate 61 is installed in the groove in a limited manner, so as to heat the first electrode plate 51. In practice, the recesses can also be provided on the collector plate 21 and are also within the scope of protection.

In order to ensure the positioning of the flexible resistance plate 61, in the case that no groove is formed on the opposite surfaces of the first polar plate 51 and the current collecting plate 21, a sealing ring member with a certain thickness is used to cooperate with the flexible resistance plate 61, so as to ensure the contact and sealing between the first polar plate 51 and the current collecting plate 21, and to ensure the compression amount of the flexible resistance plate 61 and the sealing ring member. The seal ring member forms a receiving groove for receiving the flexible resistive sheet 61, and has the same structure as the groove described above.

The thickness of the flexible resistive sheet 61 is selected based on the conductivity of the resistive sheet to calculate the resistance. Different stack currents correspond to different resistance values of the flexible resistive plate 61 according to different fuel cell stack designs. The selection principle of the resistance value is to calculate the heat generation quantity according to ohm's law and to match the flexible resistance plates 61 with different resistances according to different currents of different galvanic piles.

In the present aspect as described above, the principle of heating the cells at the end of the stack is implemented as follows.

The fuel cell stack is characterized by low voltage and high current, and the current density can reach 2A/cm according to the technical development of the current fuel cell²The design active area of the general electric pile is 200cm²The design rated current of the fuel cell stack is 300-500A. Because the current of the electric pile is large, the electric pile has high requirement on the resistance in the output circuit of the whole system, and any small resistance can generate large heat.

The flexible resistor plate 61 in the present application has the same shape and size as the first electrode plate 51 in which the coolant flows. The flexible resistance plate 61 is preferably selected to have an area corresponding to the active area of the membrane electrode 42 in the stack, and the distributed flexible resistance plate 61 is alternatively used, and a plurality of small-area flexible resistance plates 61 are distributed between the first polar plate 51 and the current collecting plate 21 to perform distributed heating on the first polar plate 51.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fuel cell stack, comprising:

the electric pile tail end plate (11) is positioned at the tail end, and the electric pile air inlet end plate (12) is positioned at the air inlet end;

a current collecting plate (21) close to the electric pile gas inlet end plate (12) and used for collecting electric energy;

the bipolar plate is positioned between the end plate (11) of the electric pile and the gas inlet end plate (12) of the electric pile, and a flexible resistance plate (61) used for heating the current collecting plate (21) is arranged between a first polar plate (51) of the bipolar plate, which is close to the current collecting plate (21), and the current collecting plate (21).

2. The fuel cell stack according to claim 1, wherein the flexible resistor plate (61) is hermetically connected to the current collecting plate (21).

3. The fuel cell stack according to claim 1, wherein a recess for receiving the flexible resistance plate (61) is provided on a face of the first electrode plate (51) opposite to the current collecting plate (21).

4. The fuel cell stack according to claim 3, wherein the depth of the groove is smaller than the thickness of the flexible resistance plate (61) after the maximum compression.

5. A fuel cell stack according to claim 3, wherein said groove opens on said first plate (51).

6. The fuel cell stack according to claim 1, wherein a seal ring member is sealingly bonded to both surfaces of the first electrode plate (51) facing the current collecting plate (21), and the seal ring member forms a receiving groove for receiving the flexible resistance plate (61).

7. The fuel cell stack according to any one of claims 1-6, wherein the flexible resistance plate (61) is the same shape and size as the coolant flow field of the first electrode plate (51).

8. The fuel cell stack according to any of claims 1-6, characterized in that the flexible resistance sheet (61) is a carbon cardboard or carbon cloth sheet having electrical resistance.