Efficient catalytic rehydration backflow type nickel-zinc battery cover and preparation method thereof

Abstract

This invention discloses a high-efficiency catalytic rehydration reflux type nickel-zinc battery cap, belonging to the field of battery processing technology. It includes a cap substrate (1), a non-precious metal catalyst layer (2), and microgroove reflux channels (3). The microgroove reflux channels (3) are grooves uniformly distributed radially or in a mesh pattern, formed on the cap substrate (1) with the center of the cap substrate (1) as the converging starting point. The non-precious metal catalyst layer (2) is attached to the surfaces of the microgroove reflux channels (3) and the cap substrate (1). This invention overcomes the technical defects of existing nickel-zinc battery caps in practical applications, such as precious metal dependence, low gas recombination efficiency, ineffective rehydration, high cost, and poor adaptability. It is a compact and stable catalytic rehydration type cap for nickel-zinc batteries.

Description

Technical Field

[0001] This invention belongs to the field of battery processing technology, specifically relating to a high-efficiency catalytic rehydration reflux type nickel-zinc battery cap and its preparation method. Background Technology

[0002] Nickel-zinc batteries, with their high specific energy density, excellent charge / discharge rate performance, good environmental compatibility, and resource renewability, have shown broad application potential in various fields such as portable energy storage devices, power tools, emergency backup power supplies, and low-speed electric vehicles, gradually becoming one of the preferred solutions to replace traditional lead-acid batteries and some lithium-ion batteries. However, in actual charge-discharge cycles, the electrolyte system of nickel-zinc batteries suffers from unavoidable water electrolysis side reactions. Under the influence of electrode potential, water molecules in the electrolyte decompose to generate hydrogen gas (negative electrode side) and oxygen gas (positive electrode side). This reaction not only leads to gas accumulation and continuous pressure increase inside the battery, but also triggers a series of chain reactions.

[0003] When the internal pressure of the battery exceeds the safety threshold, it may trigger the pressure relief valve, causing electrolyte leakage along with the gas and resulting in battery performance degradation. Furthermore, prolonged high-pressure environments can easily lead to battery casing bulging and sealing structure failure, posing potential safety risks. Simultaneously, the continuous loss of water due to electrolysis gradually increases the electrolyte concentration and decreases ion conduction efficiency, leading to a surge in battery internal resistance, rapid decay of charge and discharge capacity, and ultimately battery failure due to electrolyte desiccation. This severely restricts the cycle life and industrialization of nickel-zinc batteries.

[0004] To address the aforementioned issues, existing technologies have developed two main improvement approaches: one involves incorporating precious metal catalysts (such as platinum, palladium, and rhodium) into the electrolyte to catalyze the recombination of hydrogen and oxygen to generate water, thus achieving water recovery; the other involves optimizing the pressure relief structure and venting design of the cap to alleviate internal pressure accumulation. However, the former has significant drawbacks: precious metal materials are expensive and scarce, significantly increasing battery manufacturing costs and making it difficult to meet the demands of large-scale production; the latter can only passively alleviate internal pressure, failing to solve the water loss problem, and is prone to exacerbating electrolyte loss due to frequent pressure relief. Furthermore, while some improvement schemes attempt to introduce catalytic functions, they lack a corresponding reflux mechanism. The water generated by recombination easily adheres to the inner wall of the cap or evaporates, failing to efficiently reflux back into the cell to replenish the electrolyte, thus still failing to fundamentally solve the electrolyte drying problem. Therefore, developing a nickel-zinc battery cap that does not require precious metals, has excellent catalytic efficiency, integrates a water recirculation function, and is suitable for industrial production has become a core demand in the industry. Summary of the Invention

[0005] This invention provides a high-efficiency catalytic rehydration reflux type nickel-zinc battery cap, overcoming the technical shortcomings of existing nickel-zinc battery caps in practical applications, such as reliance on precious metals, low gas recombination efficiency, ineffective rehydration, high cost, and poor adaptability. It is a compact and stable catalytic rehydration type cap for nickel-zinc batteries. By precisely designing the catalyst system and reflux structure, it achieves rapid recombination of water electrolysis gas and efficient rehydration of generated water, suppressing the rise in battery internal pressure and electrolyte drying from the source. While controlling manufacturing costs, it significantly improves the cycle life and safety performance of nickel-zinc batteries, providing technical support for the large-scale industrial application of nickel-zinc batteries and offering a safer and more stable guarantee for the application of battery technology in new energy vehicles.

[0006] To achieve the above objectives, this application provides a high-efficiency catalytic rehydration reflux type nickel-zinc battery cap, comprising a cap substrate, a non-precious metal catalyst layer, and microgroove reflux channels; the microgroove reflux channels are grooves uniformly distributed radially or in a mesh pattern on the cap substrate, with the center of the cap substrate as the converging starting point; the non-precious metal catalyst layer is attached to the surface of the microgroove reflux channels and the cap substrate.

[0007] Furthermore, the material of the cap base is any one of nickel-plated steel plate, 304 stainless steel or 6061 aluminum alloy.

[0008] Furthermore, the non-precious metal catalyst layer is formed by the attachment of a perovskite-type catalyst or a spinel-type catalyst.

[0009] Furthermore, the perovskite catalyst is one or more of LaMnO3, LaCoO3, and SrTiO3; the spinel catalyst is one or more of Co3O4, NiFe2O4, and Mn3O4.

[0010] Furthermore, the depth of the microgroove return channel is controlled to be 0.1~0.5mm, and the width is controlled to be 0.2~0.8mm.

[0011] A method for preparing a high-efficiency catalytic rehydration reflux type nickel-zinc battery cap includes the following steps: (1) First, polish the functional surface of the cap substrate facing the inside of the battery, and then clean and dry it for later use; (2) Process the functional surface of the cap substrate after step (1) to form radial or mesh-like uniformly distributed micro-groove return channels. After completion, perform hydrophilic processing on the inner wall of the micro-groove return channels. (3) The non-precious metal catalyst is coated on the functional surface of the cap substrate, and then calcined and cooled at high temperature.

[0012] Furthermore, the cleaning described in step (1) is to remove impurities and oxide film from the functional surface of the cap substrate, and passivation treatment is also performed after cleaning.

[0013] Furthermore, the hydrophilic processing described in step (2) involves forming a hydrophilic layer on the inner wall of the microgroove return channel to ensure smooth water return.

[0014] Furthermore, the non-precious metal catalyst coating method described in step (3) is spraying, screen printing or dip-coating, and the coating load on the substrate is controlled to be 1~3 mg / cm².

[0015] Furthermore, the temperature of the high-temperature roasting in step (3) is controlled at 200~400℃ and the duration is controlled at 1~3h.

[0016] The present invention has the following advantages over the prior art: This invention offers significant cost advantages and is suitable for large-scale production: it abandons traditional precious metal catalysts and adopts perovskite or spinel-type non-precious metal catalysts, which greatly reduces material costs. Moreover, the catalysts are widely available and the preparation process is mature. At the same time, the optimized loading design of 1~3 mg / cm² maximizes the control of catalyst usage while ensuring catalytic efficiency, further reducing manufacturing costs. It can be directly adapted to the mass production needs of existing battery production lines.

[0017] The selected non-precious metal catalyst exhibits high catalytic activity and selectivity for the hydrogen-oxygen composite reaction, rapidly catalyzing the formation of water from hydrogen within the battery's normal operating temperature range (-20℃ to 60℃). The reaction rate is over 40% higher than traditional non-precious metal catalysts, effectively suppressing internal battery pressure increases and preventing safety hazards such as leakage and bulging caused by high pressure, significantly improving battery safety and stability. Furthermore, the combination of microgroove reflux channels and hydrophilic treatment technology effectively achieves directional and efficient reflux of composite water, with a water recovery rate exceeding 90%, fundamentally solving the problem of electrolyte drying. Actual testing shows that nickel-zinc batteries using this invention's cap retain over 80% of their capacity after 500 cycles at a 0.5C charge / discharge rate and room temperature, representing a cycle life improvement of over 30% compared to traditional capped batteries, significantly enhancing the battery's long-term performance. The overall structure of this invention only adds a catalyst layer and microgroove processing steps to the traditional cap, without changing the overall assembly structure of the battery, and can be adapted to nickel-zinc batteries of different specifications. The catalyst coating and microgroove processing can be achieved using existing industrial equipment without adding complex production processes, which facilitates rapid iteration and upgrading for enterprises, has broad application prospects, and can also be applied on a large scale in the new energy vehicle industry. Attached Figure Description

[0018] Figure 1This is a three-dimensional structural diagram of the nickel-zinc battery catalytic rehydration cap of the present invention.

[0019] Figure 2 This is a schematic cross-sectional view of the nickel-zinc battery catalytic rehydration cap of the present invention.

[0020] In the image above: 1. Capped substrate; 2. Non-precious metal catalyst layer; 3. Microgroove reflux channel. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of the embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0022] In the embodiments, it should be noted that any processes not specifically described below are those that can be implemented or understood by those skilled in the art by referring to existing technology. Reagents or instruments whose manufacturers are not specified are considered to be conventional products that can be purchased commercially.

[0023] Example 1 A catalytic rehydration cap adapted for D-type nickel-zinc batteries, the specific steps of which are as follows: Preparation of cap substrate 1: A nickel-plated steel plate with a thickness of 0.3 mm (nickel plating layer thickness of 5 μm) was selected and formed into a circular cap substrate with a diameter of 33 mm by precision stamping. The functional surfaces facing the inside of the battery were mechanically polished (sandpaper grit of 800 grit), ultrasonically cleaned (cleaning solution is anhydrous ethanol, cleaning time is 15 min), and vacuum dried (drying temperature is 80℃, drying time is 2 h) to thoroughly remove surface oil, oxide layer and impurities, ensuring the cleanliness of the substrate surface and providing a good base for catalyst layer bonding.

[0024] Microgroove reflux channel 3 processing: Radial microgroove reflux channels are processed on the functional surface of the cap substrate using laser engraving technology. The laser power is set to 50W and the engraving speed is 10mm / s. The groove depth is controlled to be 0.2mm and the width is controlled to be 0.5mm. Eight grooves are evenly distributed with equal spacing, starting from the center of the substrate. After processing, the inner wall of the groove is treated with plasma hydrophilic treatment technology for 5 minutes to form a stable hydrophilic surface layer and improve the water adsorption and flow capacity.

[0025] Preparation of non-precious metal catalyst layer 2: A LaMnO3 perovskite catalyst slurry (components include LaMnO3 powder, polyvinyl alcohol binder, and deionized water in a mass ratio of 8:1:11) was prepared. The slurry was uniformly coated onto the functional surface (including the microgroove area) of the cap substrate using a screen printing process (300 mesh screen). The coating thickness was controlled by adjusting the number of printing cycles to achieve a catalyst loading of 2 mg / cm². After coating, the cap was placed in a muffle furnace and heated to 300°C at a heating rate of 5°C / min. It was then calcined at a constant temperature for 2 hours and allowed to cool naturally to room temperature, so that the catalyst layer and the substrate were firmly bonded together, resulting in a cap semi-finished product.

[0026] Finished product assembly: The edges of the cap semi-finished product are ground and passivated, and a nitrile rubber sealing ring adapted to the D-type nickel-zinc battery is assembled to complete the preparation of the nickel-zinc battery catalytic rehydration cap finished product.

[0027] Performance Testing: The above-mentioned finished caps were assembled into D-type nickel-zinc batteries (rated capacity 5000mAh). A battery of the same specification equipped with a conventional cap (without catalyst or microgrooves) served as control group 1. Charge-discharge cycle tests were conducted at 0.5C rate under normal temperature (25℃) conditions. Battery capacity, internal pressure, and electrolyte state were recorded every 50 cycles. The test results are shown in Table 1 below. Table 1 Loop count Capacity retention rate (%) in Example 1 Volume retention rate (%) in control group 1 Internal pressure (MPa) in Example 1 Internal pressure (MPa) in control group 1 Electrolyte moisture loss rate (%) in Example 1 Electrolyte moisture loss rate (%) in control group 1 0 100 100 0.12 0.12 0 0 100 96.2 88.5 0.18 0.35 1.8 6.2 300 89.5 62.3 0.24 0.62 4.5 18.7 500 82.0 51.0 0.29 0.80 7.2 32.1 As shown in Table 1 above, the capped battery in Example 1 maintained a capacity retention of 82.0% after 500 cycles, with internal pressure stabilizing below 0.29 MPa and electrolyte moisture loss of only 7.2%, showing no significant drying phenomenon. In contrast, the control group battery maintained a capacity retention of only 51.0% after 500 cycles, with internal pressure rising to a maximum of 0.80 MPa, electrolyte moisture loss reaching 32.1%, and slight leakage also occurred. This indicates that the capping device of the present invention can effectively improve battery cycle stability, suppress internal pressure rise and electrolyte drying, demonstrating significant performance advantages. Furthermore, the catalyst layer adhesion in this example was 1.6 MPa, with no detachment after 500 cycles, and the microgroove moisture reflux rate was 0.06 mL / h, achieving a moisture recovery rate of 91.5%.

[0028] Example 2 A catalytic rehydration cap adapted for type C nickel-zinc batteries, the specific steps of which are as follows: Preparation of cap substrate 1: 304 stainless steel sheet with a thickness of 0.4mm is selected and stamped into a circular cap substrate with a diameter of 26mm. The surface is then pickled (5% hydrochloric acid solution, pickling time 10min) and passivated (chromate solution) to remove surface impurities and oxide film. The substrate is then dried (drying temperature 100℃, drying time 1.5h) to ensure that the substrate has good corrosion resistance and surface flatness.

[0029] Microgroove reflux channel 3 processing: A mesh-like microgroove reflux channel is processed on the functional surface of the cap substrate using a mechanical etching process. The etching solution is ferric chloride solution, and the etching depth is controlled at 0.3 mm, the groove width at 0.4 mm, and the mesh spacing at 1.5 mm. After processing, a hydrophilic silane coupling agent (KH-550) is coated on the inner wall of the groove and cured by baking at 120℃ for 30 min to form a durable hydrophilic layer, ensuring smooth water reflux.

[0030] Preparation of non-precious metal catalyst layer 2: A Co3O4 spinel catalyst slurry (Co3O4 powder, sodium carboxymethyl cellulose binder, and deionized water in a mass ratio of 9:0.8:10.2) was prepared and coated onto the functional surface of the cap substrate using a spraying process (spray gun pressure 0.3 MPa, spraying distance 15 cm), controlling the catalyst loading at 1.5 mg / cm³. 2 After coating, the product is placed in a muffle furnace and calcined at a constant temperature of 350℃ for 1.5 hours. After cooling, a capped semi-finished product with a uniform and dense catalyst layer is obtained.

[0031] Finished product assembly: To improve safety performance, seals and miniature pressure relief valves (pressure relief threshold 0.5MPa) are assembled. After passing the airtightness test, the finished product of the catalytic rehydration cap adapted to C-type nickel-zinc batteries is obtained.

[0032] Performance Testing: The finished product was assembled into a type C nickel-zinc battery (rated capacity 3000mAh) and subjected to charge-discharge cycle testing at a rate of 0.5C under normal temperature conditions. The test data are shown in Table 2 below. A conventional capped battery was set up as a control group 2. Table 2 Loop count Capacity retention rate (%) in Example 2 Volume retention rate (%) in control group 2 Internal pressure (MPa) in Example 2 Internal pressure (MPa) in control group 2 0 100 100 0.13 0.13 200 94.8 85.7 0.22 0.41 400 85.3 58.9 0.29 0.73 600 78.0 45.2 0.34 0.95 As shown in Table 2 above, the capacity retention rate of the capped battery in this embodiment is 78.0% after 600 cycles, the internal pressure is stable below 0.34 MPa, and there is no drying or leakage of the electrolyte. This represents a cycle life improvement of over 35% compared to traditional capped batteries (capacity retention rate of 45.2% after 600 cycles). The catalyst layer adhesion is 1.8 MPa, and there is no peeling or cracking after 600 cycles. The microgroove water reflux rate is 0.055 mL / h, and the water recovery rate reaches 90.8%, demonstrating excellent structural stability and performance reliability. Furthermore, the airtightness test pass rate of the cap in this embodiment is 99.2%, and the assembly accuracy for C-type nickel-zinc batteries reaches 100%.

[0033] Example 3 The difference between Example 3 and Example 1 lies in the optimization of the catalyst system and process parameters to verify the product performance under different parameters. Specific adjustments are as follows: a NiFe2O4 spinel catalyst was selected, and the catalyst loading was increased to 3 mg / cm²; the microgroove processing depth was adjusted to 0.5 mm, and the width to 0.8 mm; the catalyst layer calcination temperature was increased to 400℃, and the calcination time was shortened to 1 h. The remaining preparation steps, matrix materials, and assembly requirements are consistent with Example 1.

[0034] Performance testing: The cap prepared in this embodiment was assembled into a D-type nickel-zinc battery (rated capacity 5000mAh) and subjected to charge-discharge cycle testing under the same conditions. The test data are shown in Table 3 below: Table 3 Loop count Capacity retention rate (%) Internal pressure (MPa) Electrolyte moisture loss rate (%) Catalyst layer adhesion (MPa) 0 100 0.12 0 1.9 100 96.5 0.17 1.5 1.8 300 89.8 0.23 4.2 1.7 500 80.0 0.28 6.8 1.6 As shown in Table 3 above, the capacity retention rate of the capped battery in this embodiment is 80.0% after 500 cycles, the internal pressure is stable below 0.28 MPa, and the electrolyte moisture loss rate is 6.8%, demonstrating excellent catalytic rehydration and reflux effects. Peeling tests verified that the catalyst layer adhesion consistently remained above 1.6 MPa, with no detachment during cycling. This indicates that the technical solution of this invention possesses stable and reliable performance within the parameter range of 1~3 mg / cm² loading and 0.1~0.5 mm trench depth, exhibiting strong parameter adaptability. Furthermore, the gas recombination reaction rate in this embodiment is 1.0 mol / (L·h), the moisture reflux rate is 0.075 mL / h, and the moisture recovery rate reaches 92.3%.

[0035] Example 4 This Example 4 focuses on optimizing the catalyst composite system to improve low-temperature catalytic performance and adapt to the application requirements of nickel-zinc batteries under low-temperature conditions. The specific preparation steps are as follows: Preparation of cap substrate 1: 6061 aluminum alloy sheet with a thickness of 0.35mm was selected and stamped into a circular cap substrate with a diameter of 12.4mm. The surface was anodized (oxide layer thickness 3μm), and then ultrasonically cleaned (cleaning solution was a mixture of deionized water and acetone, volume ratio 1:1, cleaning time 20min) and vacuum dried (drying temperature 90℃, drying time 1.5h) to ensure that the substrate surface was clean and had good corrosion resistance.

[0036] Microgroove reflux channel 3 processing: Radial microgroove reflux channels are processed on the functional surface of the cap substrate using electrochemical etching technology. The etching voltage is controlled at 12V and the etching time is 8min. The trench depth is 0.25mm and the width is 0.6mm. Ten trenches are evenly distributed with the center of the substrate as the starting point and the trench spacing is consistent. After processing, plasma hydrophilic treatment is used (processing power 80W, processing time 6min) to improve the hydrophilicity of the inner wall of the trench and ensure smooth water reflux in low temperature environment.

[0037] Preparation of non-precious metal catalyst layer 2: LaMnO3-LaCoO3 composite perovskite catalyst slurry (LaMnO3 to LaCoO3 mass ratio 7:3, with added polyvinylpyrrolidone binder and deionized water, total mass ratio 8.5:0.7:10.8) was prepared and coated onto the functional surface of the cap substrate using the dip-coating method. The dipping speed was controlled at 5 mm / s, and the catalyst loading was adjusted to 2.5 mg / cm² by adjusting the number of dipping cycles. After coating, the substrate was placed in a muffle furnace and heated to 320℃ at a heating rate of 8℃ / min, and calcined at a constant temperature for 2.5 h. After natural cooling to room temperature, a cap semi-finished product with a uniform catalyst layer was obtained.

[0038] Finished product assembly: The edges of the cap semi-finished product are polished and treated with anti-oxidation. The fluororubber sealing ring adapted to AA type nickel-zinc batteries is then assembled to complete the finished product preparation.

[0039] Performance Testing: The finished product was assembled into an AA-type nickel-zinc battery (rated capacity 1500mAh) and subjected to charge-discharge cycle testing at a rate of 0.3C in a low-temperature environment (-10±2℃). The capped battery from Example 1 was used as control group 4. The test data are shown in Table 4 below. Table 4 Loop count Capacity retention rate (%) in Example 4 Volume retention rate (%) in control group 4 Internal pressure (MPa) in Example 4 Control group 4 internal pressure (MPa) The gas recombination reaction rate in Example 4 (mol / (L·h)) The reaction rate of gas recombination in the control group (mol / (L·h)) 0 100 100 0.11 0.11 1.2 0.5 100 93.6 78.9 0.19 0.42 1.1 0.45 200 87.5 65.3 0.25 0.58 1.0 0.4 400 75.0 48.0 0.32 0.76 0.95 0.38 As shown in Table 4 above, under low-temperature conditions, the capped battery of Example 4 retained a capacity of 75.0% after 400 cycles, with internal pressure stabilizing below 0.32 MPa and gas recombination reaction rate maintained above 0.95 mol / (L·h), indicating that the catalytic rehydration efficiency was not affected by low temperature. In contrast, the control group battery 4, under the same conditions, retained only 48.0% of its capacity after 400 cycles, with significant internal pressure fluctuations and a gas recombination reaction rate decreasing to 0.38 mol / (L·h). This demonstrates that the LaMnO3-LaCoO3 composite catalyst system of this example can significantly improve low-temperature catalytic performance and is suitable for use in low-temperature scenarios down to -10℃. Furthermore, the microgrooves of Example 4 showed no ice blockage under low-temperature conditions, with a water reflux rate of 0.05 mL / h and a water recovery rate of 89.6%.

[0040] Example 5 This embodiment 5 focuses on optimizing the processing technology, simplifying the production process, improving mass production efficiency, and ensuring stable product performance. The specific preparation steps are as follows: Preparation of cap substrate 1: Nickel-plated steel plate with a thickness of 0.3mm is selected and formed into circular cap substrates with a diameter of 18mm by continuous stamping process. Batch ultrasonic cleaning (cleaning solution is anhydrous ethanol, cleaning time is 12min) and hot air drying (drying temperature is 110℃, drying time is 1h) are adopted to achieve batch pretreatment and reduce production time.

[0041] Microgroove reflux channel 3 processing: The mesh microgroove reflux channel is processed in batches using a roll forming process. The speed of the roll forming roller is controlled at 20r / min and the pressure is 0.8MPa. The groove depth is 0.15mm, the width is 0.3mm, and the mesh spacing is 1.2mm. After processing, it is directly sprayed with silane coupling agent (KH-560) without additional baking and curing, simplifying the hydrophilic treatment process.

[0042] Preparation of non-precious metal catalyst layer 2: A Co3O4-NiFe2O4 composite spinel catalyst slurry was prepared (Co3O4 to NiFe2O4 mass ratio 6:4, with sodium carboxymethyl cellulose binder and deionized water added, the total mass ratio being 9:0.6:10.4). Batch coating was carried out using an automated spraying process with a spray gun pressure of 0.4 MPa, a spraying distance of 12 cm, and a catalyst loading of 1.2 mg / cm². After coating, batch calcination was carried out in a continuous calcination furnace at a constant temperature of 300℃ for 1.8 h.

[0043] Finished product assembly: An automated assembly line is used to assemble the cap semi-finished product with the sealing ring and pressure relief valve as a whole. After batch air tightness testing (test pressure 0.6MPa, pressure holding time 30s), the finished cap adapted to D-type nickel-zinc batteries is obtained.

[0044] Performance testing: Ten finished caps from this embodiment were randomly selected and assembled into a type D nickel-zinc battery (rated capacity 5000mAh). The batteries were then subjected to a charge-discharge cycle test at 0.5C rate at room temperature (25℃). Production efficiency and cost were also tested. The test data are shown in Table 5 below. Table 5 Test Project Test results of Example 5 Comparison Results of Example 1 Capacity retention rate after 500 cycles (%) 79.0~83.0 (average 81.2) The average score was 82.0, with no significant difference. Internal pressure (MPa) after 500 cycles 0.28~0.33 (average 0.30) The average value was 0.29, with no significant difference. Catalyst layer adhesion (MPa) 1.5~1.7 (average 1.6) The average score is 1.6, with no significant difference. Moisture recovery rate (%) 89.5~91.0 (average 90.2) Average score: 91.5, with a difference of ≤1.5%. As shown in Table 5 above, after 500 cycles, the capacity retention rate of the 10 samples was between 79% and 83%, the internal pressure was stable between 0.28 and 0.33 MPa, there was no catalyst layer shedding or trench blockage, and the product consistency was excellent. Compared with Example 1, this example improves production efficiency by more than 40%, reduces production cost by 15%, slightly improves product qualification rate, and has no significant performance degradation, making it more suitable for large-scale batch production. In addition, during the batch production process of this example, the microgroove processing qualification rate reached 99.5%, and the catalyst coating uniformity reached 99.0%, further verifying the stability and feasibility of the process.

[0045] This invention uses a non-precious metal catalyst (perovskite type, spinel type or their composite system) to replace the traditional precious metal catalyst. Combined with an optimized loading design of 1~3 mg / cm², it significantly reduces manufacturing costs while ensuring catalytic activity. This solves the core pain points of precious metal dependence and high mass production costs in existing technologies. Moreover, the catalyst is suitable for the alkaline electrolyte environment of nickel-zinc batteries and has excellent stability.

[0046] A novel integrated structure of "catalyst layer - microgroove reflux channel" was constructed to achieve closed-loop control of "gas production - catalytic recombination - water reflux". This breaks through the limitations of existing technologies that can only catalyze gas production or only passively depressurize and cannot achieve efficient water recirculation, thus solving the dual problems of electrolyte drying and internal pressure rise from the source.

[0047] The microgroove reflux channel adopts a radial or mesh design, combined with a hydrophilic treatment process on the inner wall, and optimized dimensions of 0.1~0.5mm depth and 0.2~0.8mm width. This ensures directional and rapid reflux of water (recovery rate ≥89.6%) without affecting the structural strength and sealing performance of the cap, thus solving the technical problem of easy adhesion and escape of composite water.

[0048] The catalyst coating and calcination process is optimized (200~400℃, 1~3h) to form a chemical bond between the catalyst layer and the cap substrate, improve adhesion (≥1.5MPa), prevent the catalyst layer from falling off during the cycle, and adapt to industrial processes such as spraying, screen printing, and dip-coating, taking into account both performance stability and mass production compatibility.

[0049] The cap base is made of corrosion-resistant metal materials such as nickel-plated steel plate, 304 stainless steel, and 6061 aluminum alloy, which are compatible with different specifications of nickel-zinc batteries (D type, C type, AA type, etc.) without changing the overall battery assembly structure, thus solving the problems of poor compatibility and easy failure due to electrolyte corrosion of existing improvement solutions.

[0050] By optimizing the catalyst composite system (such as LaMnO3-LaCoO3, Co3O4-NiFe2O4), the low-temperature catalytic performance can be improved, adapting to low-temperature conditions such as -10℃, expanding the application scenarios of nickel-zinc batteries, and overcoming the limitations of insufficient low-temperature activity of existing non-precious metal catalysts.

[0051] It should be noted that, in the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A high-efficiency catalytic rehydration reflux type nickel-zinc battery cap, characterized in that, It includes a capping substrate (1), a non-precious metal catalyst layer (2), and a microgroove reflux channel (3); the microgroove reflux channel (3) is a groove that is processed on the capping substrate (1) with the center of the capping substrate (1) as the starting point of convergence and is uniformly distributed in a radial or mesh pattern; the non-precious metal catalyst layer (2) is attached to the surface of the microgroove reflux channel (3) and the capping substrate (1).

2. The high-efficiency catalytic rehydration reflux type nickel-zinc battery cap according to claim 1, characterized in that, The material of the cap base (1) is any one of nickel-plated steel plate, 304 stainless steel or 6061 aluminum alloy.

3. The high-efficiency catalytic rehydration reflux type nickel-zinc battery cap according to claim 1, characterized in that, The non-precious metal catalyst layer (2) is formed by the attachment of a perovskite-type catalyst or a spinel-type catalyst.

4. The high-efficiency catalytic rehydration reflux type nickel-zinc battery cap according to claim 3, characterized in that, The perovskite catalyst is one or more of LaMnO3, LaCoO3, and SrTiO3; the spinel catalyst is one or more of Co3O4, NiFe2O4, and Mn3O4.

5. A high-efficiency catalytic rehydration reflux type nickel-zinc battery cap according to claim 1, characterized in that, The depth of the microgroove return channel (3) is controlled to be 0.1~0.5mm and the width is controlled to be 0.2~0.8mm.

6. A method for preparing a high-efficiency catalytic rehydration reflux type nickel-zinc battery cap as described in any one of claims 1-5, characterized in that, Includes the following steps: (1) First, polish the functional surface of the cap substrate (1) facing the inside of the battery, and then clean and dry it for later use; (2) Process the functional surface of the cap substrate (1) after step (1) to form a radial or mesh-like uniformly distributed micro-groove return channel (3), and then perform hydrophilic processing on the inner wall of the micro-groove return channel (3). (3) The non-precious metal catalyst is coated on the functional surface of the cap substrate (1), and then calcined and cooled at high temperature.

7. The method for preparing a high-efficiency catalytic rehydration reflux type nickel-zinc battery cap according to claim 6, characterized in that, The cleaning described in step (1) is to remove impurities and oxide film from the functional surface of the cap substrate (1). After cleaning, passivation treatment is also performed.

8. The method for preparing a high-efficiency catalytic rehydration reflux type nickel-zinc battery cap according to claim 6, characterized in that, The hydrophilic processing described in step (2) involves forming a hydrophilic layer on the inner wall of the microgroove return channel (3) to ensure smooth water return.

9. The method for preparing a high-efficiency catalytic rehydration reflux type nickel-zinc battery cap according to claim 6, characterized in that, The non-precious metal catalyst coating method described in step (3) is spraying, screen printing or dip-coating, and the coating load on the substrate is controlled to be 1~3 mg / cm².

10. The method for preparing a high-efficiency catalytic rehydration reflux type nickel-zinc battery cap according to claim 6, characterized in that, The temperature of the high-temperature roasting in step (3) is controlled at 200~400℃ and the duration is controlled at 1~3h.

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