CN214280039U

CN214280039U - Fuel cell stack fastening structure for improving contact resistance

Info

Publication number: CN214280039U
Application number: CN202120273693.7U
Authority: CN
Inventors: 王再平; 李骏; 甘全全; 戴威
Original assignee: Shanghai Shen Li High Tech Co Ltd
Current assignee: Shanghai Shenli Technology Co Ltd
Priority date: 2021-01-29
Filing date: 2021-01-29
Publication date: 2021-09-24
Anticipated expiration: 2031-01-29

Abstract

The utility model relates to a fuel cell stack fastening structure for improving contact resistance, which comprises a front end plate, a rear end plate, a fixed pull rod and a stack compression adjusting mechanism, wherein the fuel cell stack is arranged between the front end plate and the rear end plate and comprises a stack main body, a stack end plate and an elastic piece mounting groove arranged on the stack end plate; the pile compresses tightly adjustment mechanism includes and runs through and threaded connection is in adjusting bolt on the back end plate, locate the back end plate inboard and with the floating plate of adjusting bolt tip abutting against, and locate the elasticity between floating plate and the elastic component mounting groove and compress tightly the piece. Compared with the prior art, the utility model discloses a revolve wrong adjusting bolt in order to promote or pull out the floating plate to realize belleville spring's compression or resilience through the floating plate, and then adjust the pile end plate to the packing force of pile main part, in order to avoid the long-time operation back of pile, cause the pile to relax because of spare part elasticity performance decline, and then make the not enough problem that leads to the increase of pile integral contact internal resistance of packing force.

Description

Fuel cell stack fastening structure for improving contact resistance

Technical Field

The utility model belongs to the technical field of fuel cell, a improve contact resistance's fuel cell pile fastening structure is related to.

Background

The fuel cell stack is formed by stacking and combining a plurality of single cells in series, each single cell consists of a bipolar plate and a membrane electrode (MEA-catalyst, proton exchange membrane, carbon paper/carbon cloth), and a sealing element is embedded between the single cells and is tightly fixed and fastened after being pressed by a front end plate and a rear end plate, so that the fuel cell stack is formed. Due to the processing and manufacturing errors of the fuel cell stack and the condition that the stack pressure is different in the stack process, the problem of uneven contact of the fuel cell stack can occur in the stacking and assembling process of components such as a membrane electrode, a sealing element, a bipolar plate and the like. In addition, the fuel cell stack can cause the parts such as the membrane electrode of the fuel cell stack, a sealing element and the like to expand with heat and contract with cold due to high and low temperature circulation in the operation process, so that the whole fuel cell stack can expand and contract with each other in the length direction in the operation process, and the whole fuel cell stack is easy to increase the contact resistance due to poor contact in the long term.

The increase in contact resistance is an important factor causing the performance degradation of the fuel cell, and is also an important index for the failure diagnosis of the fuel cell. Flow field design, surface treatment, assembly processes, etc. all cause increased contact resistance. The contact resistance can be caused by both too small a contact surface and non-uniform distribution of the contact surface. Wherein the contact surface is too small for easy understanding; in electron conduction, because electrons tend to move in a path with low resistance, the uneven distribution of the contact surface means that a large number of electrons pass through a certain part or a certain parts, the local current density is too high, the local temperature is too high, and finally, hot spots occur in the membrane electrode, so that the durability of the cell is reduced or internal combustion occurs. That is, excessive local contact resistance causes local current density to increase, thereby causing local temperature to be excessively high, thereby generating hot spots, resulting in degradation of performance and durability of the fuel cell.

In addition, the main purposes of methods such as structure optimization, material optimization and improvement of a single cell forming process of parts of the single cell of the stack are to reduce the internal resistance of the single cell; the processing precision of the bipolar plate and the membrane electrode production, such as the surface roughness of the bipolar plate, the adhesion degree of the membrane electrode GDL and the catalyst layer and the like, can be controlled, and the contact resistance of the galvanic pile can be improved to different degrees. However, the current fuel cell products are mainly applied to high-power consumption scenes of buses, logistics transport vehicles, commercial vehicles and the like. For a high-power fuel cell stack, a plurality of single cells are stacked in series, and a sealing member is required between each single cell. The stacking and assembling of the plurality of single batteries is difficult to ensure the consistency of each galvanic pile for the current galvanic pile assembling process, and is not beneficial to the batch production and performance evaluation of the galvanic piles.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing an improve contact resistance's fuel cell pile fastening structure for solve because of leading to the great problem of contact resistance because of contact failure between parts such as membrane electrode, sealing member, bipolar plate in the fuel cell pile.

The purpose of the utility model can be realized through the following technical scheme:

a fuel cell stack fastening structure that improves contact resistance, comprising:

the fuel cell stack is arranged between the front end plate and the rear end plate and comprises a stack main body, a stack end plate and an elastic piece mounting groove formed in the stack end plate;

the fixed pull rod is used for fixing the distance between the front end plate and the rear end plate;

the pile compresses tightly adjustment mechanism for compress tightly the fuel cell pile, including running through and threaded connection in the adjusting bolt on the back end plate, locate the back end plate inboard and with the floating plate that adjusting bolt tip supported and press, and locate the elasticity that floats between floating plate and the elastic component mounting groove and compress tightly the piece.

Further, the elastic pressing member includes a disc spring.

Furthermore, the elastic piece mounting groove is an annular mounting groove formed in the end plate of the stack.

Furthermore, a guide piece is arranged on the pile end plate, and a guide hole is formed in the floating plate;

one end of the guide piece is fixed on the middle boss of the annular mounting groove, and the other end of the guide piece is arranged in the guide hole in a sliding mode.

Furthermore, a limiting groove is formed in the middle boss, and a limiting protrusion matched with the depth of the limiting groove is arranged on the floating plate. The depth of the limiting groove is preferably the limiting distance of the elastic pressing piece for limiting deformation failure, and the specific value can be determined according to the elastic performance of the elastic pressing piece.

Furthermore, the upper side and the lower side of the fuel cell stack are respectively provided with a fixed pull rod.

Further, a silicon rubber gasket is arranged between the fuel cell stack and the fixed pull rod.

Furthermore, the cross section of the fixed pull rod is U-shaped, can be formed by bending a thin plate, and has the advantages of light weight, high strength and rigidity and the like.

Furthermore, the front end and the rear end of the fixed pull rod are respectively provided with a mounting hole, and the front end and the rear end of the fixed pull rod are respectively fixedly connected with the front end plate and the rear end plate through mounting bolts penetrating through the corresponding mounting holes.

Furthermore, the mounting hole is a non-circular mounting hole, and the front end plate and the rear end plate are respectively provided with a buckle boss matched with the mounting hole. The shearing force of the screw is eliminated through the clamping boss, and the fixing reliability is improved.

Compared with the prior art, the utility model has the characteristics of it is following:

1) the floating plate is pushed or pulled out by screwing the adjusting bolt, so that the compression or rebound of the disc spring is realized through the floating plate, and the pressing force of the pile end plate on the pile main body is further adjusted, so that the problem that the pile is loosened due to the decline of the elastic performance of parts such as a sealing element, a membrane electrode and the like after the pile runs for a long time, and the integral contact internal resistance of the pile is increased due to the insufficient pressing force is solved;

2) after the fuel cell stack is assembled, supplementary pressing force can be applied to the stack main body in advance so that the stack can reach a pressing contact state which works optimally;

3) the conventional electric pile fastening method mostly adopts a screw and nut matched connection mode, although the structure is simple and the operation is convenient, the length of each electric pile of the same model is inconsistent due to the accumulation of manufacturing errors and assembly errors of parts, and the fixed packaging of the PACK of the electric pile is not facilitated;

4) the fuel cell stack is supported by the fixed pull rod or the fixed pull rod and the silica gel gasket together, so that the phenomenon that the fuel cell stack collapses due to vibration is prevented.

Drawings

Fig. 1 is a schematic structural view of a fuel cell stack fastening structure for improving contact resistance according to an embodiment;

FIG. 2 is a schematic structural diagram of a stack pressing adjustment mechanism in a relaxed state;

FIG. 3 is a schematic structural diagram of a stack pressing adjustment mechanism in a pressing state;

FIG. 4 is an enlarged view of a portion of FIG. 1 at A;

FIG. 5 is a schematic structural view of a fixing pull rod;

FIG. 6 is a schematic view of the floating plate;

the notation in the figure is:

the fuel cell stack structure comprises a front end plate 1, a rear end plate 2, a fixed pull rod 3, a fuel cell stack 4, a stack main body 401, a stack end plate 402, an adjusting bolt 5, a floating plate 6, an elastic pressing piece 7, a guide piece 8, a guide hole 9, a limiting groove 10, a limiting bulge 11, a silicone rubber gasket 12, a mounting hole 13, a buckle boss 14 and a mounting bolt 15.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.

Example (b):

a fuel cell stack fastening structure for improving contact resistance as shown in fig. 1 includes a front end plate 1 and a rear end plate 2, a fixing tie bar 3 for fixing a distance between the front end plate 1 and the rear end plate 2, and a stack pressing adjustment mechanism for pressing a fuel cell stack 4. The fuel cell stack 4 is arranged between the front end plate 1 and the rear end plate 2 and comprises a stack main body 401, a stack end plate 402 and an elastic piece mounting groove 403 arranged on the stack end plate 402;

as shown in fig. 2 and 3, the stack pressing adjustment mechanism includes an adjustment bolt 5 penetrating through and screwed to the rear end plate 2, a floating plate 6 (shown in fig. 6) disposed inside the rear end plate 2 and abutting against an end of the adjustment bolt 5, and an elastic pressing member 7 disposed between the floating plate 6 and the elastic member mounting groove 403.

Specifically, disk spring is selected for use as elastic pressing member 7, elastic member mounting groove 403 is an annular mounting groove formed in stack end plate 402, a screw is further arranged on a middle boss of the annular mounting groove to serve as guide member 8 of floating plate 6, guide hole 9 is formed in floating plate 6, and one end of guide member 8 is slidably arranged in guide hole 9.

In addition, a limiting groove 10 is further formed in the middle boss, and a limiting protrusion 11 matched with the depth of the limiting groove 10 is arranged on the floating plate 6. Specifically, the depth of the limiting groove 10 is the limiting distance for limiting deformation failure of the elastic pressing member 7, and thus it is ensured that the elastic pressing member 7 is always within the effective elastic working range.

As shown in fig. 1, the number of the fixed pull rods 3 is 6, and the fixed pull rods are symmetrically arranged on the upper and lower sides of the fuel cell stack 4, and a silicone rubber gasket 12 is further arranged between the fuel cell stack 4 and the fixed pull rods 3, so that the fuel cell stack 4 is supported and fixed by the fixed pull rods 3 and the silicone rubber gasket 12, and the waist collapse phenomenon of the fuel cell stack due to vibration is prevented. .

As shown in fig. 5, the cross section of the fixing rod 3 is U-shaped, rectangular mounting holes 13 are respectively formed at the front and rear ends thereof, and fastening bosses 14 (shown in fig. 4) adapted to the mounting holes 13 are respectively formed on the front end plate 1 and the rear end plate 2. During installation, the buckle boss 14 is embedded into the rectangular mounting hole 13, and then the buckle boss is fixedly connected with the rectangular mounting hole through the mounting bolt 15, so that the shearing force of a screw is eliminated, and the fixing reliability is improved.

When the fuel cell stack is assembled by adopting the fastening structure, a certain torque T is applied to the adjusting bolt 5 to generate a force F and drive the floating plate 6 to compress the disc spring downwards, so that the disc spring generates a thrust force towards the fuel cell stack to press the fuel cell stack;

in addition, after the stack is operated for a long time, along with the elastic attenuation of components such as sealing elements, membrane electrodes and the like in the stack main body 401, the pressing force of the stack main body 401 is reduced, and the stack is loosened, so that the compensation pressing force can be applied to the stack main body 401 through the adjusting bolt 5 under the condition that the fuel cell is not disassembled, the pressing effect on the stack is improved, and the contact resistance is reduced.

The embodiments described above are intended to facilitate the understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention according to the disclosure of the present invention.

Claims

1. A fuel cell stack fastening structure that improves contact resistance, characterized by comprising:

the fuel cell stack comprises a front end plate (1) and a rear end plate (2), wherein a fuel cell stack (4) is arranged between the front end plate (1) and the rear end plate (2) and comprises a stack main body (401), a stack end plate (402) and an elastic piece mounting groove (403) formed in the stack end plate (402);

the fixed pull rod (3) is used for fixing the distance between the front end plate (1) and the rear end plate (2);

the electric pile compresses tightly adjustment mechanism for compress tightly fuel cell electric pile (4), including running through and adjusting bolt (5) on rear end plate (2) of threaded connection, locate rear end plate (2) inboard and with adjusting bolt (5) tip support floating plate (6) of pressing to and locate floating plate (6) and elastic component mounting groove (403) between elasticity compress tightly piece (7).

2. The fuel cell stack fastening structure for improving contact resistance according to claim 1, wherein the elastic pressing member (7) comprises a disc spring.

3. The fuel cell stack fastening structure for improving contact resistance according to claim 2, wherein the elastic member mounting groove (403) is an annular mounting groove opened in the stack end plate (402).

4. The fuel cell stack fastening structure for improving the contact resistance according to claim 3, wherein a guide member (8) is provided on the stack end plate (402), and a guide hole (9) is provided on the floating plate (6);

one end of the guide piece (8) is fixed on a boss in the middle of the annular mounting groove, and the other end of the guide piece is slidably arranged in the guide hole (9).

5. The fuel cell stack fastening structure for improving the contact resistance according to claim 4, wherein a limiting groove (10) is formed on the middle boss, and a limiting protrusion (11) matched with the depth of the limiting groove (10) is formed on the floating plate (6).

6. The fuel cell stack fastening structure for improving contact resistance according to claim 1, wherein the fuel cell stack (4) is provided with fixing tie rods (3) at upper and lower sides thereof, respectively.

7. The fuel cell stack fastening structure for improving contact resistance according to claim 6, wherein a silicone rubber gasket (12) is further provided between the fuel cell stack (4) and the stationary tie bar (3).

8. The fuel cell stack fastening structure for improving contact resistance according to claim 6, wherein the fixing tie bar (3) has a U-shaped cross section.

9. The fuel cell stack fastening structure for improving the contact resistance according to claim 6, wherein the front end and the rear end of the fixed pull rod (3) are respectively provided with a mounting hole (13), and the front end and the rear end of the fixed pull rod (3) are respectively fixedly connected with the front end plate (1) and the rear end plate (2) through a mounting bolt (15) passing through the corresponding mounting hole (13).

10. The fuel cell stack fastening structure for improving the contact resistance according to claim 9, wherein the mounting hole (13) is a non-circular mounting hole, and the front end plate (1) and the rear end plate (2) are respectively provided with a snap boss (14) adapted to the mounting hole (13).