A kind of infiltration cleaning tool for graphite bipolar plate

Abstract

The application discloses an impregnation cleaning tool for graphite bipolar plates. The tool comprises an outer frame and a holding frame. The outer frame comprises left and right side walls, a bottom wall and a back wall which enclose a receiving cavity. The left and right side walls, the bottom wall and the back wall all comprise a hollow structure to allow liquid to flow into the receiving cavity. The holding frame comprises a plurality of spacers made of hydrophobic plastic material. The spacers are arranged side by side in the receiving cavity along the left-right direction to define a plurality of insertion slots. The graphite bipolar plates are adapted to be loaded into the insertion slots from front to back and arranged vertically. The inlet and outlet areas of the graphite bipolar plates are located at the upper and lower ends, and the flow field reaction areas are located between the two inlet and outlet areas. The spacers are provided with a set of reinforcing strips corresponding to the inlet and outlet areas and a flow guide strip corresponding to the flow field reaction area. The flow guide strip comprises a plurality of inclined sections to disturb and guide the liquid flow between the flow field reaction areas of adjacent two graphite bipolar plates. The distance between the middle flow field reaction areas of adjacent two graphite bipolar plates defined by the spacers is not less than 2 mm.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to an impregnation and cleaning fixture for graphite bipolar plates. Background Technology

[0002] Graphite bipolar plates, as a core component of fuel cells, offer advantages over bipolar plates made of other materials, including excellent conductivity, lightweight construction, and low cost. In the manufacturing process of graphite bipolar plates, the impregnation process is one of the most crucial steps. The quality of the impregnation process directly determines the strength, sealing, and conductivity of the bipolar plate.

[0003] The impregnation process involves immersing the molded graphite bipolar plate in a specific resin solution, allowing the resin material to penetrate the interlayer spaces of the graphite layers. After impregnation, the graphite bipolar plate is cleaned and cured in a water bath. Throughout the process, the molded graphite bipolar plate remains on a fixture and is not removed until the graphite bipolar plate is fully cured. However, due to the extremely low surface energy of the resin, it easily adheres to the gaps between the tooling and the plates, making cleaning difficult and increasing cleaning costs. Especially when the spacing between adjacent bipolar plates is small, liquid flow between adjacent bipolar plates, particularly in large areas such as the flow field reaction zone and distribution zone, becomes difficult, severely affecting the cleaning effect in these areas.

[0004] Therefore, it is necessary to propose a technical solution to overcome the shortcomings of existing technologies. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, this invention proposes an immersion cleaning fixture for graphite bipolar plates to improve the cleaning effect.

[0006] This invention is achieved through the following technical solution: an impregnation and cleaning fixture for graphite bipolar plates, comprising an outer frame and a retainer disposed within the outer frame. The outer frame includes at least left and right side walls, a bottom wall, and a rear wall, which enclose a receiving cavity. The left and right side walls, bottom wall, and rear wall of the outer frame all include a perforated structure to allow liquid to flow into the receiving cavity in the front-to-back, left-to-right, and up-down directions. The retainer includes multiple spacers made of hydrophobic plastic, which are arranged side-by-side in the receiving cavity along the left-to-right direction to define the receiving cavity as a plurality of slots for inserting graphite bipolar plates at intervals in the left-to-right direction. The graphite bipolar plates are adapted to be inserted into the retainer from front to back. The plates are arranged vertically in the slots, such that the inlet and outlet areas of each graphite bipolar plate, which have medium inlets and outlets, are located at the upper and lower ends, and the flow field reaction zone is located between the two inlet and outlet areas. The spacer is provided with a group of reinforcing strips corresponding to the inlet and outlet areas. The reinforcing strips are used to contact the graphite bipolar plate to keep it upright. The spacer is also provided with a flow guide strip corresponding to the flow field reaction zone. The flow guide strip includes multiple inclined sections extending obliquely in the vertical direction to disturb and guide the liquid flow between the middle flow field reaction zones of two adjacent graphite bipolar plates. The distance between the middle flow field reaction zones of two adjacent graphite bipolar plates defined by the spacer is not less than 2 mm.

[0007] As a further improved technical solution, the partition includes a rectangular outline, the guide strip is located within the outline and extends in a wavy shape in the vertical direction.

[0008] As a further improved technical solution, the crest and trough of the wave-shaped guide strip are respectively connected to the two sides of the outline frame in the width direction.

[0009] As a further improved technical solution, the reinforcing strip group is disposed at both ends of the outline frame in the length direction, and the reinforcing strip group includes several reinforcing strips that are respectively connected to two sides of the outline frame in the width direction.

[0010] As a further improved technical solution, the outline frame, guide strip, and reinforcing strip are all made of cylindrical plastic strips with a diameter between 2.5 and 4.5 mm.

[0011] As a further improved technical solution, the partition is a PTFE or PFA injection molded part.

[0012] As a further improved technical solution, the retainer includes several pads, which are disposed at both ends of the spacer in the vertical direction and between two adjacent spacers to support the insertion slot formed between the two adjacent spacers, and the width of the insertion slot is not greater than 3mm.

[0013] As a further improved technical solution, the pad and the partition are detachably connected, and the pad includes at least two types with different heights, and the two types of pads are interchangeably assembled to the partition; or, each partition is fixedly connected with several pads, and the partition includes at least two types with pads of different heights fixedly attached, and the two types of partitions are interchangeably assembled to the receiving cavity.

[0014] As a further improved technical solution, the outer frame includes a strip-shaped baffle disposed on its front side, the two ends of which are detachably connected to the left and right side walls.

[0015] As a further improved technical solution, the upper ends of the left and right side walls are provided with lifting components to facilitate the lifting and placement of the immersion cleaning fixture.

[0016] The impregnation cleaning fixture for graphite bipolar plates provided by this invention employs a hydrophobic plastic material as a separator, giving it hydrophobic properties to reduce the adhesion of impregnation resin between the fixture and the graphite bipolar plate, thus reducing cleaning difficulty. Furthermore, the separator is equipped with a flow guide strip corresponding to the flow field reaction zone of the graphite bipolar plate. This flow guide strip includes multiple inclined sections extending obliquely in the vertical direction to disturb and guide the liquid flow between the central flow field reaction zones of adjacent graphite bipolar plates. The distance between the central flow field reaction zones of adjacent graphite bipolar plates, defined by the separator, is not less than 2 mm. This design enhances the flow and rinsing ability of the cleaning liquid between adjacent graphite bipolar plates, especially between the central flow field reaction zones, thereby improving the cleaning effect. Attached Figure Description

[0017] Figure 1 This is a three-dimensional assembly diagram of an embodiment of the immersion cleaning fixture of the present invention.

[0018] Figure 2 This is another perspective view of an embodiment of the immersion cleaning fixture of the present invention.

[0019] Figure 3 This is a three-dimensional assembly diagram of an embodiment of the immersion cleaning fixture of the present invention, which is equipped with a graphite bipolar plate.

[0020] Figure 4 This is a three-dimensional exploded view of an embodiment of the immersion cleaning fixture of the present invention.

[0021] Figure 5 This is a perspective view of the partition in one embodiment of the immersion cleaning fixture of the present invention.

[0022] Figure 6 This is a perspective view of the graphite bipolar plate that can be assembled into the immersion cleaning fixture of the present invention.

[0023] Figure 7This is a schematic diagram of the structure of the partition and graphite bipolar plate in the immersion cleaning fixture of the present invention.

[0024] Explanation of reference numerals: 100-Immersion cleaning fixture; 11-Left and right side walls; 111-Mounting port; 12-Bottom wall; 13-Rear wall; 14-Strip baffle; 141-Hook; 15-Rear baffle; 16-Lifting component; 2-Separator; 21-Outline frame; 22-Reinforcing strip group; 23-Guide strip; 201-Insertion slot; 3-Padded block; 5-Graphite bipolar plate; 51-Inlet and outlet area; 510-Media inlet and outlet; 52-Flow field reaction zone; 53-Distribution zone. Detailed Implementation

[0025] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0027] The present invention provides an impregnation and cleaning fixture 100 for a graphite bipolar plate 5, which is used to carry the graphite bipolar plate 5 during the impregnation process and the cleaning process after impregnation, and immerse it in the impregnation solution or the cleaning solution.

[0028] The immersion cleaning fixture 100 includes an outer frame and a retainer disposed within the outer frame. The outer frame includes at least left and right side walls 11, a bottom wall 12, and a rear wall 13, which enclose a receiving cavity. The left and right side walls 11, bottom wall 12, and rear wall 13 of the outer frame all include a perforated structure to allow liquid to flow into the receiving cavity in the front-back, left-right, and up-down directions. The retainer includes multiple spacers 2 made of hydrophobic plastic, which are arranged side-by-side in the receiving cavity in the left-right direction to define the receiving cavity as a plurality of insert slots 201 for placing graphite bipolar plates 5 side-by-side at intervals in the left-right direction. The graphite bipolar plates 5 are adapted to be inserted into the insert slots 201 from front to back and are arranged vertically, such that each graphite bipolar plate 5 has an inlet / outlet area 510 for media inlet / outlet 510 located at the upper and lower ends, and a flow field reaction zone 52 located between the two inlet / outlet areas 51.

[0029] The partition 2 is provided with a reinforcing strip group 22 consisting of several reinforcing strips corresponding to the inlet and outlet area 51. The reinforcing strip group 22 is used to contact the graphite bipolar plate 5 to keep it in an upright state. The partition 2 is provided with a flow guide strip 23 corresponding to the flow field reaction area 52. The flow guide strip 23 includes multiple inclined sections that extend obliquely in the vertical direction to disturb and guide the liquid flow between the middle flow field reaction areas 52 of two adjacent graphite bipolar plates 5. The distance between the middle flow field reaction areas 52 of two adjacent graphite bipolar plates 5 defined by the partition 2 is not less than 2 mm.

[0030] The impregnation and cleaning fixture 100 for graphite bipolar plates 5 provided by this invention employs a hydrophobic plastic material septum 2, giving it hydrophobic properties to reduce the adhesion of impregnation resin between the impregnation and cleaning fixture and the graphite bipolar plate 5, thus reducing the cleaning difficulty. Furthermore, the septum 2 is provided with a guide strip 23 corresponding to the flow field reaction zone 52 of the graphite bipolar plate 5. The guide strip 23 includes multiple inclined sections extending obliquely in the vertical direction. This arrangement allows the hydrophobic guide strip 23 to effectively break the surface tension of the liquid between the narrow adjacent graphite bipolar plates 5, creating a turbulence effect and guiding the liquid flow. This improves the flow and rinsing ability of impregnation liquid, cleaning liquid, and other liquids between adjacent graphite bipolar plates 5, especially between the central flow field reaction zone 52 of adjacent graphite bipolar plates 5, thereby enhancing the impregnation and cleaning effect.

[0031] Please see Figures 1 to 4As shown, in this embodiment, the outer frame includes left and right side walls 11, a bottom wall 12, and a rear wall 13, which enclose a receiving cavity. Further, the outer frame may also include a top wall and a front wall. In this embodiment, the outer frame includes a strip-shaped baffle 14 disposed on its front side, which constitutes the front wall. The two ends of the strip-shaped baffle 14 are detachably connected to the left and right side walls 11 to facilitate the insertion and removal of the graphite bipolar plate 5 and the spacer 2 from the front side of the outer frame. In this embodiment, the strip-shaped baffle 14 has folded hook portions 141 at both ends, and the left and right sidewalls 11 have locking slots 111. The folded portions 141 can be placed at the locking slots 111 in the front-back direction, and then the strip-shaped baffle 14 can be moved up or down to be locked at the front edge of the left and right sidewalls 11, preventing the graphite bipolar plate 5 from sliding out from the front of the outer frame during immersion or cleaning. Furthermore, in this embodiment, a rear baffle 15 is also provided at the rear wall 13. The rear baffle 15 has the same structure as the strip-shaped baffle 14, and its two ends are detachably connected to the rear edge of the left and right sidewalls 11. The left and right sidewalls 11, bottom wall 12, rear wall 13, top wall, and front wall of the outer frame, as well as the partition 2, all include a hollow structure to allow liquid to flow into the receiving cavity in the front-back, left-right, and up-down directions. The upper ends of the left and right sidewalls 11 are provided with lifting members 16 to facilitate the lifting and placement of the impregnation and cleaning fixture 100, so as to facilitate manual or hanging machine lifting of the impregnation and cleaning fixture 100. The front-back, left-right, and up-down directions mentioned above are indicated by arrows in the attached drawings, which are relative to the side where the operator usually places the graphite bipolar plate 5 when picking it up or placing it.

[0032] Please refer to this carefully. Figure 4 and Figure 5As shown, the retainer is composed of multiple spacers 2 arranged at equal intervals. The spacers 2 are injection molded from PTFE (polytetrafluoroethylene) or PFA (soluble polytetrafluoroethylene), exhibiting excellent hydrophobicity and chemical stability. In this embodiment, each spacer 2 includes a rectangular outline 21, a group of reinforcing strips 22 located within the outline 21, and a guide strip 23. In this embodiment, the reinforcing strip group 22 is located along the length of the outline 21, specifically at both ends in the vertical direction. The reinforcing strip group 22 includes several reinforcing strips, which are respectively connected to two sides in the width direction of the outline 21. The guide strip 23 is located within the outline 21 and extends in a wavy shape in the vertical direction. The crests and troughs of the wavy guide strip 23 are respectively connected to two sides in the width direction of the outline 21 to improve connection strength and enhance the overall structural strength of the spacer 2. The retainer includes a plurality of pads 3, which are disposed at both ends of the spacers 2 in the vertical direction and between two adjacent spacers 2, so as to support the insertion slots 201 formed between the two adjacent spacers 2 for inserting and holding the graphite bipolar plates 5.

[0033] Please refer to the following: Figure 6 and Figure 7 As shown, in this embodiment, the width d of the insert groove 201 defined by the pad block 3 is no greater than 3 mm. In some embodiments, the thickness of the graphite bipolar plate 5 is about 1 mm. If the width d is too large, on the one hand, the number of graphite bipolar plates 5 that can be accommodated in the impregnation cleaning fixture 100 with the same volume will decrease, resulting in a decrease in impregnation cleaning efficiency; on the other hand, it will also increase the swaying space of the graphite bipolar plate 5 placed in the insert groove 201 and increase the tilt angle of the graphite bipolar plate 5, affecting the impregnation and cleaning effect. If the width d is too small, for example, basically the same as the thickness of the graphite bipolar plate 5, on the one hand, it will be difficult to insert the graphite bipolar plate 5; on the other hand, it will cause all parts of the spacer 2 to contact the graphite bipolar plate 5, resulting in an increase in the area of ​​the graphite bipolar plate 5 that is contacted and covered by the spacer 2, affecting the impregnation and cleaning effect. Preferably, for a graphite bipolar plate 5 with a thickness of approximately 1±0.2 mm, the width d of the insert slot 201 is 1.5~2.5 mm.

[0034] Of course, in other embodiments, the width of the insert slot 201 varies depending on the thickness of the graphite bipolar plate 5. In some embodiments, the pad 3 is detachably connected to the spacer 2, and the pad 3 includes at least two types with different heights, and the two types of pad 3 are interchangeably fitted onto the spacer 2. In other embodiments, a plurality of pads 3 are fixedly connected to each spacer 2, and the spacer 2 includes at least two types with pads 3 fixedly attached at different heights, and the two types of spacers 2 are interchangeably fitted into the receiving cavity. This arrangement allows the size of the insert slot 201 to be adjustable to accommodate graphite bipolar plates 5 of different sizes, or to meet the clamping requirements of different clamping degrees in different situations.

[0035] In some embodiments, since the size of the insert slot 201 is larger than the thickness of the graphite bipolar plate 5, the graphite bipolar plate 5 will be slightly tilted and upright when placed in the insert slot 201. In other words, the upright state described in this invention refers to the graphite bipolar plate 5 being arranged vertically in the impregnation cleaning fixture, and does not imply that it should be absolutely vertical; tilting is permissible. Because the graphite bipolar plate 5 is tilted in the insert slot 201, the inlet and outlet areas 51 at the upper and lower ends of the graphite bipolar plate 5 will contact the spacer 2. To ensure the strength of the spacer 2 and provide better support performance, the spacer 2 is provided with reinforcing strip groups 22 corresponding to the inlet and outlet areas 51 of the graphite bipolar plate 5. In this embodiment, the reinforcing strip group 22 includes multiple laterally extending reinforcing strips. Although the setting of the reinforcing strip group 22 will reduce the hollow area at this point, since the reinforcing strip group 22 corresponds to the inlet and outlet area 51 of the graphite bipolar plate 5, which has medium inlet and outlet 510 for oxygen, hydrogen and water to enter and exit, the liquid at this point can flow fully. Therefore, the reduction of the hollow area at this point will not have an adverse effect on the liquid flow at this point.

[0036] Please see Figure 6As shown, in this embodiment, the guide strip 23 is located outside the flow field reaction zone 52 of the graphite bipolar plate 5. In other embodiments, it may further extend to the distribution zone 53 of the graphite bipolar plate 5. For the narrow space formed between the flow field reaction zones 52 of two adjacent graphite bipolar plates 5, in the prior art, to alleviate the poor liquid flow at this location, the common approach is to maximize the perforated area of ​​the immersion cleaning fixture, such as completely perforating the partition 2 or, to simultaneously ensure support performance, sparsely placing several crossbars. However, while complete perforation seems to reduce flow obstruction, since the liquid here can only flow laminarly along the surface of the flow field reaction zone 52, the liquid will form a water film due to surface tension in the narrow space with a relatively large surface area, resulting in poor flowability. This invention utilizes a guide strip 23 corresponding to the area. The guide strip 23 comprises multiple inclined segments extending obliquely in the vertical direction. On one hand, it acts as a flow disruptor, causing the liquid flow within the narrow space between the flow field reaction zones 52 of adjacent graphite bipolar plates 5 to be disturbed and transformed, thus helping to break the surface tension of the liquid between the narrow adjacent graphite bipolar plates 5 and promoting its flow. On the other hand, the multiple inclined segments guide the liquid to flow obliquely, improving rinsing capacity and uniformity. Furthermore, since the guide strip 23 itself is made of hydrophobic fluoroplastic, it further promotes liquid flow and enhances the guiding effect. In this embodiment, the guide strip 23 is wavy in the vertical direction, guiding the liquid flow in a wavy pattern. Simultaneously, this corrugated structure also prevents local warping and deformation of the graphite bipolar plates 5 during the curing process.

[0037] In this embodiment, the distance D between the central flow field reaction zones 52 of two adjacent graphite bipolar plates 5 defined by the partition 2 is not less than 2 mm; in other words, the thickness of the partition 2 is not less than 2 mm. In this embodiment, the partition 2 is entirely composed of cylindrical plastic strips, that is, the diameter of the cylindrical plastic strips is not less than 2 mm. Specifically, in this embodiment, the contour frame 21, the guide strip 23, and the reinforcing strip are all composed of cylindrical plastic strips with a diameter between 2.5 and 4.5 mm. Preferably, they are composed of cylindrical fluoroplastic strips with a diameter of 3 mm, 3.5 mm, or 4 mm. Using a cylindrical shape results in a linear actual contact surface with the graphite bipolar plate 5, a small contact area, and better turbulence and water guiding effects than planar columns such as square columns.

[0038] As described above, the impregnation cleaning fixture 100 for graphite bipolar plates 5 provided by the present invention, on the one hand, uses a hydrophobic plastic material partition 2, which has hydrophobic properties, reducing the adhesion of impregnation resin between the impregnation cleaning fixture and the graphite bipolar plate 5, and reducing the cleaning difficulty; on the other hand, the partition 2 is provided with a guide strip 23 corresponding to the flow field reaction zone 52 of the graphite bipolar plate 5. The guide strip 23 includes multiple inclined sections extending obliquely in the vertical direction to disturb and guide the liquid flow between the middle flow field reaction zones 52 of two adjacent graphite bipolar plates 5. The distance between the middle flow field reaction zones 52 of two adjacent graphite bipolar plates 5 defined by the partition 2 is not less than 2mm. This setting improves the flow and rinsing ability of the cleaning liquid between two adjacent graphite bipolar plates 5, especially between the middle flow field reaction zones 52 of two adjacent graphite bipolar plates 5, thereby improving the cleaning effect.

[0039] This invention has been illustrated through several specific embodiments. Those skilled in the art will understand that various modifications and equivalent substitutions can be made to this invention without departing from its scope. Furthermore, various modifications can be made to this invention for specific situations or circumstances without departing from its scope. Therefore, this invention is not limited to the specific embodiments disclosed, but should include all embodiments falling within the scope of the claims.

Claims

1. A permeation cleaning fixture for graphite bipolar plates, comprising an outer frame and a retainer disposed within the outer frame, the outer frame comprising at least left and right side walls, a bottom wall, and a rear wall, the left and right side walls, the bottom wall, and the rear wall enclosing a receiving cavity, wherein the left and right side walls, the bottom wall, and the rear wall of the outer frame each include a perforated structure to allow liquid to flow into the receiving cavity in the front-back, left-right, and up-down directions, characterized in that, The retainer includes multiple spacers made of hydrophobic plastic, arranged side-by-side in the receiving cavity to define the cavity as several slots for placing graphite bipolar plates side-by-side at intervals in the left-right direction. The graphite bipolar plates are adapted to be inserted into the slots from front to back and are arranged vertically, such that the inlet and outlet areas of each graphite bipolar plate, with media inlets and outlets, are located at the upper and lower ends, and the flow field reaction zone is located between the two inlet and outlet areas. Each spacer has a reinforcing strip group consisting of several reinforcing strips corresponding to the inlet and outlet areas. The reinforcing strip group is used to contact the graphite bipolar plate to keep it upright. Each spacer also has a flow guide strip corresponding to the flow field reaction zone, the flow guide strip including multiple inclined sections extending obliquely in the vertical direction to disturb... The spacer guides the liquid flow between the central flow field reaction zones of two adjacent graphite bipolar plates, and the distance between the central flow field reaction zones of two adjacent graphite bipolar plates defined by the spacer is not less than 2 mm. The retainer also includes several pads, which are disposed at both ends of the spacer in the vertical direction and located between two adjacent spacers to support the insertion slot formed between the two adjacent spacers, and the width of the insertion slot is not greater than 3 mm. The pads are detachably connected to the spacers, and the pads include at least two types with different heights, and the two types of pads are interchangeably assembled to the spacers. Alternatively, several pads are fixedly connected to each spacer, and the spacers include at least two types with fixed pads of different heights, and the two types of spacers are interchangeably assembled to the receiving cavity.

2. The impregnation and cleaning fixture for graphite bipolar plates as described in claim 1, characterized in that, The partition includes a rectangular outline, and the guide strip is located within the outline and extends in a wavy shape in the vertical direction.

3. The impregnation and cleaning fixture for graphite bipolar plates as described in claim 2, characterized in that, The crests and troughs of the wave-shaped guide strip are respectively connected to the two sides of the outline frame in the width direction.

4. The impregnation and cleaning fixture for graphite bipolar plates as described in claim 2, characterized in that, The reinforcing strip group is located at both ends of the outline frame along its length, and the reinforcing strip group includes several reinforcing strips that are respectively connected to two sides of the outline frame along its width.

5. The impregnation and cleaning fixture for graphite bipolar plates as described in claim 4, characterized in that, The outline frame, guide strip, and reinforcing strip are all made of cylindrical plastic strips with a diameter between 2.5 and 4.5 mm.

6. The impregnation and cleaning fixture for graphite bipolar plates as described in any one of claims 1 to 5, characterized in that, The spacer is a PTFE or PFA injection molded part.

7. The impregnation and cleaning fixture for graphite bipolar plates as described in any one of claims 1 to 5, characterized in that, The outer frame includes a strip-shaped baffle disposed on its front side, the two ends of which are detachably connected to the left and right sidewalls.

8. The impregnation and cleaning fixture for graphite bipolar plates as described in claim 7, characterized in that, The upper ends of the left and right side walls are provided with lifting components to facilitate the lifting and placement of the immersion cleaning fixture.

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