Electrode frame structure for a flow battery

Abstract

The utility model relates to a kind of electrode frame structure of liquid flow battery, comprising: frame, including placement groove, the frame is equipped with the through hole along the through hole of thickness direction, the placement groove is set around the through hole;Mounting piece is installed in the placement groove, the first surface of the mounting piece is sealed with the groove bottom surface of the placement groove Connection, the overlapping portion of the mounting piece edge and the groove bottom surface of the placement groove is spaced with multiple fixed holes;Rubber coating, at the edge position of the second surface of the mounting piece, the outer circumferential side of the rubber coating is bonded with the inside wall of the placement groove, part of the rubber coating extends into the fixed hole, and the fixed hole is filled;Wherein, the frame and rubber coating are non-integral structure of independent injection molding.The electrode frame structure of the utility model can effectively ensure the sealing, avoid leakage, high reliability, and can reduce production cost.

Description

Technical Field

[0001] This utility model relates to the field of flow batteries, and more specifically, to an electrode frame structure for a flow battery. Background Technology

[0002] Flow batteries are a highly efficient electrochemical energy storage technology. The working medium of a flow battery is an electrolyte, typically an acidic liquid. Electrolyte loss not only reduces charging and discharging energy but also causes environmental pollution or safety accidents. In the entire flow battery system, the stack is its core power component and also the weakest point in the system's seal. A flow battery stack usually consists of multiple components, including electrodes, ion-conducting membranes, electrode frames, bipolar plates, current collectors, and end plates. A problem in the sealing of any of these components can lead to serious consequences; therefore, ensuring the airtightness between all internal components of a flow battery is crucial.

[0003] In vanadium redox flow battery systems, bipolar plates and ion-exchange membranes are installed within the electrode frame. During installation, it is crucial to ensure a tight seal between the bipolar plates, ion-exchange membrane, and electrode frame to prevent leakage during use. Currently, the primary method for assembling bipolar plates (or ion-exchange membranes) and electrode frames is laser welding. However, due to the different materials of the electrode frame and bipolar plates (or ion-exchange membranes), their coefficients of thermal expansion differ. Temperature changes during laser welding can easily cause deformation of the electrode frame, leading to weld detachment and poor connection stability. Furthermore, during cooling after welding, the different degrees of contraction between the electrode frame and bipolar plates (or ion-exchange membranes) can create gaps at the weld, compromising sealing and causing leakage during subsequent use, resulting in poor reliability. Additionally, laser welding of each electrode frame is time-consuming and inefficient. Moreover, laser welding requires specialized equipment and professional operator training, further increasing production costs.

[0004] In addition, some electrode frames are currently produced by injection molding directly around the periphery of the bipolar plate (or ion membrane) using a mold. After injection molding, the bipolar plate (or ion membrane) is embedded in the center of the electrode frame. That is, the electrode frame is manufactured and assembled in one injection molding process. However, since plastic shrinks in volume when it cools during injection molding, the injection-molded electrode frame will strongly pull on the central bipolar plate (or ion membrane) when it shrinks. However, the bipolar plate (or ion membrane) will resist deformation, resulting in a certain degree of bending in the final electrode frame product, which affects the quality. Utility Model Content

[0005] In view of this, the purpose of this utility model is to provide an electrode frame structure for a flow battery with good sealing performance and high reliability. This electrode frame structure can effectively ensure sealing performance, prevent leakage, improve production quality, and reduce production costs.

[0006] The objective of this utility model is achieved through the following technical solution.

[0007] An electrode frame structure for a flow battery includes: a frame body including a placement groove, the frame body having a through hole along its thickness direction, the placement groove surrounding the through hole; a mounting member installed in the placement groove, including a first surface and a second surface opposite to each other, the first surface of the mounting member being sealed to the bottom surface of the placement groove, and the overlapping portion of the edge of the mounting member and the bottom surface of the placement groove having a plurality of fixing holes spaced apart; an adhesive layer disposed at the edge of the second surface of the mounting member, the outer periphery of the adhesive layer being bonded to the inner sidewall of the placement groove, a portion of the adhesive layer extending into the fixing holes and filling the fixing holes; wherein the frame body and the adhesive layer are independently injection molded, non-integral structures.

[0008] In the above technical solution, the first surface of the mounting component faces the bottom surface of the placement groove and abuts against the bottom surface of the placement groove. The adhesive layer is located at the edge of the second surface of the mounting component and is bonded to the inner wall of the placement groove, so that the mounting component is sealed with the frame. The frame and the adhesive layer are obtained by injection molding.

[0009] It should be noted that, due to the different materials of the frame and the mounting parts, their coefficients of thermal expansion and contraction are different. When the mounting parts are connected to the frame by laser welding, the temperature change during welding will cause the frame to deform at the welding point. After cooling, due to the difference in contraction between the two, gaps are easily formed at the welding point, and even detachment may occur, affecting the sealing performance. This can easily lead to leakage during use and result in low reliability. This application achieves sealing through an overlay layer. Since both the overlay layer and the frame are injection molded, deformation caused by temperature changes and shrinkage differences can be avoided, effectively ensuring the seal between the frame and the mounting component. Furthermore, multiple fixing holes are provided on the edge of the mounting component where it overlaps with the placement groove. During the injection molding of the overlay layer, plastic enters and fills these fixing holes, forming multiple columnar fixing structures. This enhances the stability of the overlay layer's adhesion, preventing it from loosening even under external forces, ensuring a good seal and improving reliability. In addition, since both the frame and the overlay layer are injection molded from plastic, the overlay layer can be thermally bonded to the sidewall of the placement groove during injection molding, greatly enhancing the seal and making the connection more stable, further improving the reliability of the seal.

[0010] Furthermore, since laser welding requires specialized equipment, additional equipment must be purchased, and specialized personnel must be trained to operate it, resulting in higher costs. In this application, the overmolded layer is injection molded, and the frame itself is also injection molded. Therefore, production can be achieved using only an injection molding machine, eliminating the need for additional equipment investment and labor costs, effectively reducing production costs. Moreover, because the overmolded layer is injection molded, a standardized mold can be used for processing, which, compared to laser welding, effectively shortens processing time, improves production efficiency, and ensures the consistency of the structure of each electrode frame.

[0011] It is worth mentioning that some electrode frames in the prior art are directly injection molded around the periphery of the mounting component using a mold. After injection molding, the mounting component remains in the center of the electrode frame, meaning the electrode frame is manufactured and assembled in a single injection molding process. However, since plastic shrinks in volume when cooling, the shrinking of the injection-molded electrode frame strongly pulls on the central mounting component, which resists deformation. This causes the electrode frame to bend to a certain extent, resulting in a bent final electrode frame and affecting quality. This application achieves sealing by separately injection molding and overmolding. Compared to the one-piece molding method in the prior art, this ensures a good sealing effect while preventing the frame from bending after cooling.

[0012] In one example of this invention, the mounting component is a bipolar plate or an ion exchange membrane.

[0013] In the above technical solution, the flow battery energy storage system is composed of multiple flow battery cells stacked together. Each flow battery cell includes multiple electrode frames. Some electrode frames are equipped with bipolar plates, and others are equipped with ion exchange membranes. The two play different roles.

[0014] In one example of this utility model, the portion of the adhesive layer extending into the fixing hole is bonded to the bottom surface of the placement groove.

[0015] In the above technical solution, since both the overlay layer and the frame are injection molded, the part of the overlay layer that enters the fixing hole during injection molding can be thermally bonded to the bottom surface of the placement groove, thereby enhancing the connection stability.

[0016] In one example of this utility model, the fixing holes are distributed in a triangular pattern along the edge of the mounting component.

[0017] In the above technical solutions, the triangular distribution pattern is more stable, which makes the adhesion of the coating layer more secure.

[0018] In one example of this utility model, the area of ​​the fixing hole accounts for 10-25% of the area of ​​the overlapping portion between the edge of the mounting component and the bottom surface of the placement groove.

[0019] In the above technical solution, in order to ensure the stability of the adhesive layer adhesion, the area of ​​the fixing hole needs to account for 10-25% of the overlapping area of ​​the edge of the mounting part and the bottom surface of the placement groove.

[0020] In one example of this utility model, the placement groove is square, and the mounting component matches the shape of the placement groove.

[0021] In the above technical solution, since most bipolar plates are square, the placement slot is set to be square to match the shape of the bipolar plate. Correspondingly, in order to ensure that multiple electrode frames are matched when stacked in the future, the ion membrane is also set to be square.

[0022] In one example of this utility model, the thickness of the frame is 2.0-5.0 mm.

[0023] In the above technical solution, to ensure the rationality of the stacking structure, the thickness of the frame is in the range of 2.0-5.0mm.

[0024] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0025] This invention uses an adhesive layer to seal the mounting component and the frame. Since both the adhesive layer and the frame are injection molded, compared with traditional laser welding, deformation caused by temperature changes and shrinkage differences can be avoided, effectively ensuring the sealing between the frame and the mounting component. At the same time, multiple fixing holes are opened at the edge of the mounting component, and the adhesive layer fills the fixing holes, enhancing the adhesion stability of the adhesive layer, making it less prone to loosening even under the influence of external forces, ensuring the sealing effect and improving reliability.

[0026] The frame and the rubber coating of this utility model are both injection molded. The rubber coating can be heat-fused to the side wall of the placement groove, which greatly enhances the sealing performance and makes the connection more stable, further improving the reliability of the seal.

[0027] This invention achieves sealing by overmolding, which, compared to the existing technology of directly injection molding the frame around the mounting parts, ensures a good sealing effect while avoiding bending of the frame due to shrinkage, thus improving product quality.

[0028] The frame and the rubber coating in this invention are both injection molded, so they can be produced using only an injection molding machine without additional equipment investment or labor costs, thus effectively reducing production costs.

[0029] The coating layer of this invention can be processed by setting a uniform mold. Compared with laser welding, it can effectively shorten the processing time, improve production efficiency, and ensure the consistency of each electrode frame structure. Attached Figure Description

[0030] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a perspective view of the electrode frame structure of the flow battery according to Embodiment 1 of this utility model.

[0032] Figure 2 for Figure 1 Exploded view.

[0033] Figure 3 This is a top view of the electrode frame structure of the flow battery in Example 1.

[0034] Figure 4 for Figure 3 A cross-sectional view at position AA in the middle.

[0035] Figure 5 This is an exploded view of the electrode frame structure of the flow battery according to Embodiment 2 of this utility model.

[0036] Figure 6 This is a top view of the bipolar plate of Embodiment 3 of this utility model.

[0037] Explanation of the reference numerals in the figure:

[0038] 1-Frame; 11-Through hole; 12-Placement slot; 2-Bipolar plate; 3-Coating layer; 4-Fixing hole; 5-Ion membrane. Detailed Implementation

[0039] To facilitate understanding of this invention, a more comprehensive description will be provided below with reference to the accompanying drawings. The drawings illustrate preferred embodiments of the invention. However, this invention can be implemented in many different forms and is not limited to the embodiments described herein. Example 1

[0040] Please refer to Figures 1 to 4An electrode frame structure for a flow battery includes a frame 1, bipolar plates 2, and an adhesive layer 3. The frame 1 includes a placement groove 12 and a through hole 11 extending along its thickness direction. The placement groove 12 surrounds the through hole 11. The bipolar plates 2 include opposing first and second surfaces. The bipolar plates 2 are installed in the placement groove 12. The first surface of the bipolar plates 2 is sealed to the bottom surface of the placement groove 12. The overlapping portion of the edge of the bipolar plates 2 and the bottom surface of the placement groove 12 is provided with a plurality of fixing holes 4 at intervals. The adhesive layer 3 is located at the edge of the second surface of the bipolar plates 2. The outer periphery of the adhesive layer 3 is bonded to the inner wall of the placement groove 12. A portion of the adhesive layer 3 extends into the fixing holes 4 and fills the fixing holes 4.

[0041] like Figure 2 As shown, the side of the bipolar plate 2 closest to the placement groove 12 is the first side, and the side furthest from the placement groove 12 is the second side. After the overlay layer 3 is injection molded, the first side of the bipolar plate 2 is tightly attached to the bottom surface of the placement groove 12. The overlay layer 3 is located at the edge of the second side of the bipolar plate 2 and is bonded to the inner wall of the placement groove 12, so that the bipolar plate 2 is sealed with the frame 1, ensuring the sealing between the bipolar plate 2 and the frame 1 and preventing leakage during use. The frame 1 and the overlay layer 3 are obtained by injection molding.

[0042] Specifically, in the manufacturing process of the electrode frame structure of this utility model, the frame 1 is first obtained by injection molding through a mold, then the bipolar plate 2 is placed in the placement groove 12, and then the frame 1 is placed in the overmolding mold to form the overmolding layer 3 by injection molding, thus obtaining the final product.

[0043] Preferably, the frame 1 is made of PP (polypropylene), the coating layer is also made of PP, and the bipolar plate 2 is made of graphene.

[0044] It should be noted that, since the frame 1 is made of PP, which has a large coefficient of thermal expansion and contraction, while the bipolar plate 2 is made of graphene, which has a smaller coefficient of thermal expansion and contraction, when connecting the bipolar plate 2 to the frame 1 by laser welding, the temperature change during welding will cause the frame 1 to deform at the weld. After cooling, due to the difference in the shrinkage rate between the frame 1 and the bipolar plate 2, gaps are likely to appear at the weld, and even detachment may occur, which seriously affects the sealing performance. During use, leakage is likely to occur, affecting the normal use of the flow battery and resulting in low reliability. This invention uses an overlay layer 3 to seal the frame 1. Since both the overlay layer 3 and the frame 1 are injection molded and made of the same material, deformation caused by temperature changes and shrinkage differences can be avoided, effectively ensuring the seal between the frame 1 and the bipolar plate 2. Furthermore, multiple fixing holes 4 are formed on the edge of the bipolar plate 2 where it overlaps with the placement groove 12. During injection molding of the overlay layer 3, plastic enters and fills the fixing holes 4, forming multiple columnar fixing structures. This strengthens the stability of the overlay layer 3's adhesion, making it less prone to loosening or falling off even under external forces, ensuring a good seal and improving reliability. In addition, since both the frame 1 and the overlay layer 3 are made of PP material, during injection molding, the overlay layer 3 can be heat-fused to the side wall of the placement groove 12, greatly enhancing the seal. The portion of the overlay layer 3 extending into the fixing holes can also be heat-fused to the bottom surface of the placement groove 12, forming a stable connection and further improving the reliability of the seal.

[0045] Furthermore, since laser welding requires specialized laser welding equipment, additional equipment needs to be purchased, and specialized personnel need to be trained to operate it, resulting in higher costs. In this application, the overmolded layer 3 is injection molded, and the frame 1 itself is also injection molded. Therefore, production can be achieved using only an injection molding machine, eliminating the need for additional equipment investment and effectively reducing production costs. Moreover, since the overmolded layer 3 is obtained through injection molding, it can be processed using a standardized mold, ensuring consistency across the various electrode frame structures compared to laser welding.

[0046] It is worth mentioning that some electrode frames in the prior art are directly injection molded around the bipolar plate 2 using a mold. After injection molding, the bipolar plate 2 is then embedded in the center of the electrode frame, completing the electrode frame manufacturing and assembly in a single injection molding process. However, since plastic shrinks during injection molding and cooling, the molded electrode frame will strongly pull on the central bipolar plate 2 during shrinkage. The bipolar plate 2 resists deformation, causing the electrode frame to bend to a certain extent, resulting in a bent final electrode frame and affecting quality. This invention achieves sealing through separate injection molding and overmolding. Compared to the one-piece molding method in the prior art, the overmolding layer 3 is small in volume and located only at the edge, so its shrinkage effect is negligible. Therefore, it avoids the bending of the frame 1 after cooling.

[0047] Preferably, since the bipolar plate 2 is square, the placement slot 12 is set to be square to match the shape of the bipolar plate 2.

[0048] It is understandable that since the current bipolar plate 2 is usually square, this embodiment will use a square bipolar plate 2 as an example for introduction. The specific shape can be flexibly adjusted according to actual needs.

[0049] In this embodiment, in order to ensure the stability of the adhesive layer 3, the area of ​​the fixing hole 4 needs to be 10-25% of the area of ​​the overlapping part between the edge of the bipolar plate 2 and the bottom surface of the placement groove 12.

[0050] In this embodiment, to ensure the rationality of the stacking structure of the flow battery energy storage system, the thickness of the frame 1 is controlled within the range of 2.0-5.0 mm.

[0051] It should be noted that the frame 1 structure in this embodiment is for demonstration purposes only, and the flow channels, liquid passage holes and other liquid passage structures provided on it are not shown in the figure. Example 2

[0052] Please refer to Figure 5 This embodiment is basically the same in structure and principle as Embodiment 1. The difference is that the placement groove 12 in this embodiment is used to install the ion membrane 5. The size of the ion membrane 5 is smaller than the outer diameter of the placement groove 12. A part of the adhesive layer 3 extends into the placement groove 12 and is attached and bonded to the side wall and bottom surface of the placement groove 12, thereby sealing and pressing the ion membrane 5 into the placement groove 12. This ensures both the fixing effect of the ion membrane 5 and the sealing effect.

[0053] It should be noted that multiple fixing holes 4 are also provided at the edge of the ion membrane 5. Since the ion membrane 5 is relatively thin and the adhesive layer 3 is bonded to the bottom surface and side surface of the placement tank 12, the stability of the adhesive layer 3 is already guaranteed. Therefore, the main function of the fixing holes 4 in this embodiment is to enhance the stability of the ion membrane 5 installation. The part of the adhesive layer 3 extending into the fixing hole 4 can be bonded to the bottom surface of the placement tank 12, thereby fixing the ion membrane 5, thus preventing the ion membrane 5 from wrinkling or shifting due to impact, improving the reliability during use, and the stability of the overall structure.

[0054] Preferably, the thickness of the ion exchange membrane 5 is 0.04-0.05 mm.

[0055] It is understandable that fixing hole 4 can be as shown in the attached figure. Figures 1 to 5 As shown, one row is set. In other embodiments, multiple rows of fixing holes 4 can also be set. When multiple rows of fixing holes 4 are set, the fixing holes 4 can be distributed in an array or staggered. The specific arrangement can be flexibly adjusted according to actual needs. Example 3

[0056] Please refer to Figure 6 The structure and principle of this embodiment are basically the same as those of embodiment 1. The difference is that the fixing holes 4 in this embodiment are distributed in a triangular pattern on the edge of the bipolar plate 2. The triangular distribution pattern has stronger stability and can make the adhesion of the adhesive layer 3 more stable.

[0057] Similarly, the fixing holes 4 on the ion membrane 5 can also be arranged in a triangular staggered distribution. Example 4

[0058] This embodiment provides a molding process for an electrode frame structure to obtain the electrode frame structures as shown in Embodiments 1, 2, and 3, which includes the following steps:

[0059] S1: A frame 1 with through holes 11 and placement grooves 12 is obtained by injection molding using the first mold;

[0060] S2: Machine a fixing hole 4 at the edge of the mounting part;

[0061] S3: Place the mounting component into the placement slot 12, with the first surface of the mounting component facing the bottom surface of the placement slot 12;

[0062] S4: Place the frame 1 with the mounting parts into the second mold, and form a coating layer 3 at the edge of the second side of the mounting parts by injection molding.

[0063] It should be noted that the mounting component is either a bipolar plate 2 or an ion exchange membrane 5.

[0064] The first mold and the second mold are used for injection molding of the frame 1 and the overlay layer 3, respectively, and their specific structures are designed according to actual needs. In S4, during injection molding, the material of the overlay layer 3 can automatically enter and fill the fixing hole 4, and can be thermally fused to the bottom surface of the placement groove 12, thereby effectively strengthening the connection stability of the overlay layer 3 and preventing it from falling off. At the same time, the overlay layer 3 is also thermally fused to the side wall of the placement groove 12, effectively ensuring sealing and preventing leakage.

[0065] Preferably, in S4, to ensure molding effect and quality, the barrel temperature in the injection molding process is 180-250℃ and the injection pressure is 60-90MPa.

[0066] Preferably, in step S4, to ensure the molding quality of the overmolding layer 3, the holding pressure time in the injection molding overmolding is 20 seconds, and the holding pressure is 20-40 MPa.

[0067] In this embodiment, both the frame 1 and the overlay layer 3 are made of polypropylene (PP) injection molding. Since the frame 1 and the overlay layer 3 are made of the same material, the overlay layer 3 is easily bonded to the frame 1 by hot melt during injection molding, which enhances the sealing performance and forms a stable connection. This can effectively prevent the overlay layer 3 from falling off later, thereby greatly improving the sealing performance and reliability of the electrode frame structure.

[0068] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0069] Furthermore, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0070] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The various embodiments can be combined as needed, and the same or similar parts can be referred to each other.

[0071] The above description of the disclosed embodiments enables those 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 general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not 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. An electrode frame structure for a flow battery, characterized in that, include: A frame, including a placement groove, wherein the frame has a through hole extending along the thickness direction, and the placement groove is arranged around the through hole; The mounting component is installed in the placement groove and includes a first surface and a second surface facing each other. The first surface of the mounting component is sealed to the bottom surface of the placement groove. The overlapping part of the edge of the mounting component and the bottom surface of the placement groove is provided with a plurality of fixing holes at intervals. An adhesive layer is provided at the edge of the second surface of the mounting component. The outer peripheral side of the adhesive layer is bonded to the inner sidewall of the placement groove. A portion of the adhesive layer extends into the fixing hole and fills the fixing hole. The frame and the overlay layer are independently injection molded, non-integrated structures.

2. The electrode frame structure of the flow battery according to claim 1, characterized in that, The mounting component is a bipolar plate or an ion exchange membrane.

3. The electrode frame structure of the flow battery according to claim 1, characterized in that, The portion of the adhesive layer extending into the fixing hole is bonded to the bottom surface of the placement groove.

4. The electrode frame structure of the flow battery according to claim 1, characterized in that, The fixing holes are arranged in a triangular pattern along the edge of the mounting component.

5. The electrode frame structure of the flow battery according to claim 1, characterized in that, The area of ​​the fixing hole accounts for 10-25% of the area of ​​the overlapping portion between the edge of the mounting component and the bottom surface of the placement groove.

6. The electrode frame structure of the flow battery according to claim 1, characterized in that, The placement slot is square, and the mounting component matches the shape of the placement slot.

7. The electrode frame structure of the flow battery according to claim 1, characterized in that, The thickness of the frame is 2.0-5.0 mm.

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