Method for connecting and sealing air electrode of aluminum-air cell stack

Abstract

The invention discloses a method for connecting and sealing air electrodes of an aluminum-air cell stack. The method comprises the following steps of: loading a single cell frame into an injection mold; mounting the air electrode assembly on the positioning column of the plastic mold, and fixedly connecting the single battery frame and the air electrode assembly by the positioning column on the mold at the same time, so that the welding positions of the single battery frame and the air electrode assembly correspond to each other; the mold is closed; after mold closing, the air electrode assembly and the single battery frame are tightly pressed by the front mold and the rear mold, and a high-temperature plastic solution is injected into the injection molding machine after mold closing; opening the mold; the cooled plastic solution structure is the bonding piece. The formed single battery frame is firmly bonded with the air electrode, the bonding surface is good in consistency, the forming speed is high, the bonding surface is high in chemical corrosion resistance, and excellent sealing performance is achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of air batteries, and particularly relates to a method for connecting and sealing an air electrode of an aluminum-air battery stack. Background Art

[0002] An aluminum-air battery uses metallic aluminum as the negative electrode and oxygen as the positive electrode. There is a pair of air electrodes on both sides of the aluminum-air battery, serving as the positive electrode of the aluminum-air battery. An electrode liquid of KOH / NaOH solution is filled between the aluminum anode and the air electrode. On the one hand, the air electrode plays a role in oxygen reduction catalysis. On the other hand, the structure and the housing form a cavity for storing the electrolyte. To ensure that the electrolyte does not leak during the operation of the battery, the air electrode and the housing must be firmly bonded and effectively sealed.

[0003] The aluminum-air electrode is generally a multi-layer composite structure. In terms of material properties, the air electrode has poor adhesiveness with most adhesives. At the same time, when the aluminum-air battery is working, the air electrode is in a high-temperature and strongly corrosive electrolyte environment for a long time, which poses extremely high requirements on the adhesive performance, corrosion resistance, high-temperature resistance, and anti-aging performance of the adhesive. It is difficult for the conventional bonding method to bond the air electrode and the monomer battery frame stably and reliably for a long time, and the bonding process has poor consistency and low efficiency, which is not conducive to production operations.

[0004] At present, the technology of bonding and sealing the monomer battery case and the air electrode is still one of the technical difficulties faced in the industry, and the leakage of the electrolyte from the air electrode of the monomer battery is also common in the industry. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for connecting and sealing an air electrode of an aluminum-air battery stack to solve the problems of unreliable bonding and sealing and leakage of the electrolyte from the air electrode of the monomer battery in the prior art.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A method for connecting and sealing an air electrode of an aluminum-air battery stack, the steps are as follows: Step 1: Install the monomer battery frame into the injection mold. Step 2: Install the air electrode assembly on the positioning posts of the plastic mold. At this time, the monomer battery frame and the air electrode assembly are simultaneously fixedly connected by the positioning posts on the mold, so that the welding positions of the two correspond to each other. Step 3: Close the mold; after closing the mold, the front and rear molds tightly press the air electrode assembly and the monomer battery frame, and after the injection mold closes, inject high-temperature plastic melt; to ensure the product quality, the following settings are made for each production parameter: 1) Dry the polymer plastic raw material particles (which can be one or more alloy materials among ABS, POM, PA, PE, and PP). Control the drying temperature at 70 - 80°C, the drying time at 3 - 4 hours, and the maximum water content within 0.01% to remove the moisture in the material. 2) During the injection molding process, set the back pressure at 300 - 600 kg / cm² and the screw speed at 30 - 60 rpm to provide appropriate pressure and speed for the injection of the material. 3) Set the melt temperature at 210 - 220°C. Control the barrel temperature in zones. The rear zone is 190 - 210°C, the middle zone is 200 - 220°C, the front zone is 200 - 220°C, and the nozzle temperature is maintained at 210 - 220°C to ensure good fluidity of the material. 4) Connect the mold to a mold temperature controller and control the mold temperature at 50 - 60°C. Step 4: Open the mold; the cooled plastic melt structure is the bonding part.

[0007] Furthermore, the air electrode assembly consists of an air electrode reaction area, a metal mesh and a conductive sheet arranged around the air electrode reaction area; the conductive sheet is welded to the metal mesh and is at a certain distance from the edge of the air electrode reaction area; at least two positioning holes corresponding to the positioning holes on the single cell are provided on the conductive sheet.

[0008] Furthermore, the single cell frame contains a welding area corresponding to the outer contour shape of the air electrode assembly. A welding surface and a plastic melt flow groove are provided on the welding area; the plastic melt flow groove partially intersects with the metal mesh hole part in the air electrode assembly in terms of position.

[0009] Furthermore, the bonding part consists of an outer wrapping area, an inner wrapping area, a sealing and blocking area, and an air electrode bonding and fixing area.

[0010] Furthermore, the outer wrapping area bonds the outer wall surfaces around the air electrode. The inner wrapping area bonds with the inner side surfaces around the air electrode on one hand and with the single cell frame on the other hand. The sealing and blocking area is arranged at the edge of the air electrode reaction area to connect the outer wrapping area and the inner wrapping area together. On one hand, it forms a flow channel for the melt from the outer wrapping area to the inner wrapping area. On the other hand, it bonds and seals the cut surface of the air electrode. The metal mesh of the air electrode is sandwiched in the middle of the sealing and blocking area, and the melt flows from the outer wrapping area to the inner wrapping area through the mesh holes of the metal mesh. Air electrode fixing holes are provided on the outer surface of the air electrode bonding and fixing area for fixing the air electrode assembly during injection molding. The conductive sheet and the metal mesh included in the air electrode assembly are also wrapped inside the air electrode bonding and fixing area, and this area contacts and bonds with the single cell frame.

[0011] Furthermore, an air electrode fixing hole is provided on the outer surface of the air electrode bonding and fixing area, which is used to facilitate the mold to fix the air electrode assembly during injection molding.

[0012] The formed single cell frame of the present invention is firmly bonded to the air electrode, has good bonding surface consistency, fast forming speed, strong chemical corrosion resistance of the bonding surface, and has excellent sealing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A schematic diagram of a single cell frame and an air electrode assembly that need to be sealed and connected in the present invention; Figure 2 A diagram showing the connection relationship between the adhesive component and the single cell frame and the air electrode assembly; Figure 3 is a schematic diagram of an air electrode assembly; Figure 4 Schematic diagram of the single cell frame and air electrode assembly in Example 1; Figure 5 It is a diagram of the cutaway position of a single cell; Figure 6 for Figure 5 AA section view; Figure 7 for Figure 6 The enlarged view of point B; Figure 8 is a schematic diagram of the air electrode assembly in Example 1; Figure 9 Schematic diagram of the relationship between various regions of the adhesive and the single cell frame and air electrode assembly in Example 1. DETAILED DESCRIPTION

[0014] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0015] Those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific technology, connection relationship or condition is specified in the examples, the technology, connection relationship, condition described in the literature in the field or the product specification is used. If the manufacturer of the materials, instruments or equipment used is not specified, they are all conventional products that can be purchased.

[0016] Combined with Figures 1 - 3 As shown, the present invention provides an aluminum-air battery stack air electrode connection and sealing method, the steps are as follows: Step 1: Place the single cell frame 100 into the injection mold. Step 2: Install the air electrode assembly 200 on the positioning posts of the plastic mold. At this time, the single cell frame 100 and the air electrode assembly 200 are simultaneously fixedly connected by the positioning posts on the mold, making the welding positions of the two correspond to each other. Step 3: Close the mold. After closing the mold, the front and rear molds tightly press the air electrode assembly 200 and the single cell frame 100 together, and after the injection mold is closed, inject high-temperature plastic melt. To ensure product quality, the following settings are made for each production parameter: 1) Dry the polymer plastic raw material particles (which can be one or more alloy materials of ABS, POM, PA, PE, and PP). The drying temperature is controlled at 70 - 80 °C, the drying time is 3 - 4 hours, and the maximum water content needs to be controlled within 0.01% to remove the moisture in the material. 2) During the injection process, the back pressure is set at 300 - 600 kg / cm², and the screw speed is 30 - 60 rpm to provide appropriate pressure and speed for the injection of the material, ensuring that the injection process not only ensures that the melt fully flows to fill the mold cavity but also avoids defects such as flash. 3) The melt temperature is set at 210 - 220 °C. The barrel temperature is controlled in zones. The rear zone is 190 - 210 °C, the middle zone is 200 - 220 °C, the front zone is 200 - 220 °C, and the nozzle temperature is maintained at 210 - 220 °C to ensure that the material has good fluidity and at the same time avoid poor bonding caused by too low temperature, material burning, and matrix deformation caused by too high temperature. 4) Connect the mold to the mold temperature controller and control the mold temperature at 50 - 60 °C. Step 4: Open the mold. The cooled plastic melt structure is the bonding part 300. The bonding part 300 bonds the air electrode assembly 200 and the single cell frame 100 together, and its cross-sectional shape is as shown in the appendix Figure 2 as follows.

[0017] Specifically, the single cell frame 100 includes a welding area corresponding to the outer contour shape of the air electrode assembly 200. A welding surface and a plastic melt flow groove are provided on the welding area. The plastic melt flow groove partially intersects with the metal mesh hole part in the air electrode assembly. The air electrode assembly 200 is composed of an air electrode reaction area 201, a metal mesh 202 arranged around the air electrode reaction area 201, and a conductive sheet 203. The conductive sheet 203 is welded to the metal mesh 202 and is at a certain distance from the edge of the air electrode reaction area. At least two positioning holes corresponding to the positioning holes on the single cell are provided on the conductive sheet 203.

[0018] Specifically, the bonding member 300 is composed of an outer wrapping area, an inner wrapping area, a sealing and blocking area, and an air electrode bonding and fixing area. The outer wrapping area bonds to the outer wall surface around the air electrode. The inner wrapping area bonds to the inner side surface around the air electrode on one hand and bonds to the single cell frame on the other hand. The sealing and blocking area is set at the edge of the air electrode reaction area, connecting the outer wrapping area and the inner wrapping area together. On one hand, it forms a flow channel for the melt to flow from the outer wrapping area to the inner wrapping area. On the other hand, it bonds and seals the cut surface of the air electrode. There is a metal mesh of the air electrode sandwiched in the middle of the sealing and blocking area, and the melt flows from the outer wrapping area to the inner wrapping area through the mesh holes of the metal mesh. The outer surface of the air electrode bonding and fixing area is provided with air electrode fixing holes for fixing the air electrode assembly during injection molding. The air electrode bonding and fixing area also wraps the conductive sheet and the metal mesh included in the air electrode assembly, and this area contacts and bonds to the single cell frame. The outer surface of the air electrode bonding and fixing area is provided with air electrode fixing holes for facilitating the mold to fix the air electrode assembly 200 during injection molding.

[0019] The materials selected for the single cell frame and the injection molding bonding structure have similar properties. They can be materials with the same chemical composition or different chemical composition polymer injection molding materials. The two materials need to be able to fuse with each other. Among them, the single cell frame needs to select a polymer material with a slightly higher molding temperature than the injection molding bonding structure. Example 1

[0020] As Figures 4 - 9 shown, a method for connecting and sealing the air electrode of an aluminum-air battery stack places the single cell frame A400 and the air electrode assembly A500 in an injection mold. After the injection molding machine closes the mold, high-temperature plastic melt is injected. The plastic melt structure after opening the mold and cooling is the bonding member A600.

[0021] As Figure 7 shown, a welding surface 402 and a plastic melt flow groove 401 are provided on the single cell shell.

[0022] As Figure 8 shown, a metal mesh A502 is provided around the air electrode reaction area A501, and a conductive sheet A503 is welded on the metal mesh. During injection molding, the high-temperature plastic melt fills the mold cavity, and the plastic melt after cooling is the bonding member A600.

[0023] As Figure 9As shown, the bonding part A600 mainly consists of an outer wrapping area 601 of the air electrode, an inner wrapping area 602, a sealing and blocking area 603, and an air electrode bonding and fixing area 604. The outer wrapping area 601 mainly bonds the outer wall surfaces around the air electrode. The inner wrapping area 602 bonds with the inner side surfaces around the air electrode on one hand and bonds with the monomer battery frame A400 at the same time on the other hand. The sealing and blocking area 603 is arranged at the edge of the air electrode reaction area, connecting the outer wrapping area 601 and the inner wrapping area 602 together; on one hand, it forms a flow channel for the melt from the outer wrapping area 601 to the inner wrapping area 602; on the other hand, it bonds and seals the cut surface of the air electrode. Among them, a metal mesh 502 of the air electrode is sandwiched in the sealing and blocking area 603, and the melt flows from the outer wrapping area 601 to the inner wrapping area 602 through the mesh holes of the metal mesh 502. An air electrode fixing hole 605 is arranged on the outer surface of the air electrode bonding and fixing area, which is mainly used to fix the air electrode assembly A500 during injection molding; the conductive sheet 503 and the metal mesh 502 included in the air electrode assembly A500 are also wrapped in the air electrode bonding and fixing area 604, and this area is in contact with and bonded to the monomer battery frame A400.

[0024] As described above, the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any minor modifications, equivalent replacements, and improvements made to the above embodiments based on the technical essence of the present invention should be included within the protection scope of the technical solution of the present invention.

Claims

1. A method for connecting and sealing an air electrode of an aluminum-air battery stack, characterized in that, The steps are as follows: Step 1: Place the single-cell frame (100) into the injection mold; Step 2: Install the air electrode assembly (200) on the positioning posts of the plastic mold. At this time, the single-cell frame (100) and the air electrode assembly (200) are simultaneously fixedly connected by the positioning posts on the mold, making the welding positions of the two correspond to each other; Step 3: Close the mold. After closing the mold, the front and rear molds tightly press the air electrode assembly (200) and the single-cell frame (100). After the injection molding machine closes the mold, inject high-temperature plastic melt. To ensure product quality, the following settings are made for each production parameter: 1) Dry the polymer plastic raw material particles. The drying temperature is controlled at 70 - 80 °C, the drying time is 3 - 4 hours, and the maximum water content needs to be controlled within 0.01% to remove the moisture in the material; 2) During the injection molding process, the back pressure is set at 300 - 600 kg / cm², and the screw speed is 30 - 60 rpm to provide appropriate pressure and speed for the injection of the material; 3) The melt temperature is set at 210 - 220 °C. The barrel temperature is controlled in zones. The rear zone is 190 - 210 °C, the middle zone is 200 - 220 °C, the front zone is 200 - 220 °C, and the nozzle temperature is maintained at 210 - 220 °C to ensure that the material has good fluidity; 4) Connect the mold to a mold temperature controller and control the mold temperature at 50 - 60 °C; Step 4: Open the mold. The cooled plastic melt structure is the bonding part (300).

2. A method for connecting and sealing an air electrode of an aluminum-air battery stack according to claim 1, characterized in that The air electrode assembly (200) consists of an air electrode reaction zone (201), a metal mesh (202) and a conductive sheet (203) arranged around the air electrode reaction zone (201); the conductive sheet (203) is welded to the metal mesh (202) and is at a certain distance from the edge of the air electrode reaction zone; at least two positioning holes corresponding to the positioning holes on the single cell are provided on the conductive sheet (203).

3. A method for connecting and sealing an air electrode of an aluminum-air battery stack according to claim 1, characterized in that, The single-cell frame (100) includes a welding area corresponding to the outer contour shape of the air electrode assembly (200). A welding surface and a plastic melt flow groove are provided on the welding area; the plastic melt flow groove partially intersects with the metal mesh hole part in the air electrode assembly in terms of position.

4. A method for connecting and sealing an air electrode of an aluminum-air battery stack according to claim 1, characterized in that, The bonding part (300) consists of an outer wrapping area, an inner wrapping area, a sealing and blocking area, and an air electrode bonding and fixing area.

5. A method for connecting and sealing an air electrode of an aluminum-air battery stack according to claim 4, characterized in that, The outer wrapping area bonds to the outer wall surface around the air electrode. The inner wrapping area, on the one hand, bonds to the inner side surface around the air electrode, and on the other hand, simultaneously bonds to the monomer cell frame. The sealing and blocking area is arranged at the edge of the air electrode reaction area, connecting the outer wrapping area and the inner wrapping area together. On the one hand, it forms a flow channel for the melt from the outer wrapping area to the inner wrapping area. On the other hand, it bonds and seals the cut surface of the air electrode. The metal mesh of the air electrode is sandwiched in the middle of the sealing and blocking area, and the melt needs to pass through the mesh holes of the metal mesh when flowing from the outer wrapping area to the inner wrapping area. The outer surface of the air electrode bonding and fixing area is provided with air electrode fixing holes for fixing the air electrode assembly during injection molding. The air electrode bonding and fixing area also wraps the conductive sheet and the metal mesh included in the air electrode assembly, and this area contacts and bonds to the monomer cell frame.

6. A method for connecting and sealing an air electrode of an aluminum-air battery stack according to claim 4 or 5, characterized in that The outer surface of the air electrode bonding and fixing area is provided with air electrode fixing holes for facilitating the mold to fix the air electrode assembly (200) during injection molding.

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