A lead-acid battery grid and its manufacturing method

Abstract

This invention discloses a lead-acid battery grid and its manufacturing method, relating to the field of electrochemical energy storage technology. The grid of this invention comprises an aluminum-based mesh layer and a lead-based mesh layer pressed onto both surfaces of the aluminum-based mesh layer. The manufacturing method involves pressing lead strips onto both surfaces of an aluminum strip, followed by stamping and cutting to obtain the composite grid. This invention significantly reduces the complexity of the aluminum-lead composite grid manufacturing process by using a pressing method to composite lead and aluminum. Simultaneously, to overcome technical barriers, an induction coil is used to preheat the aluminum strip before pressing. On one hand, this reduces alumina at high temperatures, decreasing the amount of alumina adhering to the aluminum strip surface, which helps reduce battery internal resistance and lead-aluminum connectivity. On the other hand, heating brings the aluminum strip surface close to a molten state, reducing hardness and further facilitating the pressing of the aluminum and lead strips. After pressing, the strip is less prone to detachment, resulting in high grid stability.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical energy storage technology, and in particular relates to a lead-acid battery grid and its manufacturing method. Background Technology

[0002] The grid of a lead-acid battery is one of its most important components, significantly impacting the utilization and performance of the battery's active materials. Its primary function is to support the electrode active materials and conduct current. Currently, improving the energy density of lead-acid batteries to achieve "lightweight and high energy" is a crucial criterion for judging the advancement of lead-acid battery technology. Grid lightweighting is of great significance for reducing the weight of lead-acid batteries. The main measure for grid lightweighting is to replace lead grids with low-density, lead-free conductive materials. These lead-free grid materials must be able to support the active materials, ensure sufficient contact area between the active materials and the electrolyte, minimize the battery's internal resistance, and remain stable in the electrolyte.

[0003] Among them, aluminum and its alloys are inexpensive, have excellent electrical conductivity, high mechanical strength, low density, and can be passivated in sulfuric acid solution. Even if aluminum ions enter the electrolyte, they have little impact on battery performance, making them a relatively ideal grid material for lead-acid batteries.

[0004] However, the problem with aluminum-based grids is that aluminum is a relatively reactive metal and is easily oxidized. The formation of aluminum oxide on the surface makes it difficult for aluminum and lead to combine, which affects the battery's operating efficiency.

[0005] Lead plating on aluminum grids can effectively mitigate the corrosion of the aluminum substrate. Traditional aluminum-lead composite processes generally require a transition layer to be plated on the aluminum substrate surface first. For example, patent 01135605.7 discloses a method for producing a lead-plated lightweight high-conductivity grid, which requires pre-plating zinc or copper on the aluminum plate surface as a transition layer before applying lead. Another example is patent 200710065927.3, which discloses a method for preparing a lead-aluminum composite anode plate, using an immersion method to pre-plat a layer of other metals on the aluminum plate surface.

[0006] However, the above-mentioned aluminum-lead composite grid fabrication process requires many and complex pretreatment steps, resulting in high production costs and making it unsuitable for practical applications. Summary of the Invention

[0007] The purpose of this invention is to provide a lead-acid battery grid and its manufacturing method. The method involves pressing an aluminum-based mesh layer and a lead-based mesh layer together to form a composite grid, while using heating to reduce the influence of aluminum oxide on the aluminum plate surface. This solves the problems in the prior art where the aluminum-lead composite grid preparation process involves many complex steps, high production costs, and is not conducive to practical applications.

[0008] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0009] This invention relates to a lead-acid battery grid, comprising an aluminum-based mesh layer and a lead-based mesh layer laminated to both surfaces of the aluminum-based mesh layer. The thickness of the aluminum-based mesh layer is 0.4-0.8 mm, and the thickness of the lead-based mesh layer is 0.3-0.6 mm.

[0010] As a preferred technical solution of the present invention, the lead-based mesh layer adopts one of lead-tin alloy, lead-antimony alloy, lead-calcium alloy or lead-rare earth alloy.

[0011] A method for manufacturing a lead-acid battery grid includes the following steps:

[0012] Step 1: Press aluminum strip and lead strip raw materials of a set thickness using continuous casting and rolling equipment;

[0013] Step 2: Convey the raw materials in the order of upper lead strip, middle aluminum strip, and lower lead strip;

[0014] Step 3: Heat the aluminum strip;

[0015] Step 4: Stack and press lead strip-aluminum strip-lead strip in this order to form a composite strip;

[0016] Step 5: Use stamping equipment to stamp the composite strip into a grid strip;

[0017] Step 6: Use a cutting device to cut the grid strip to obtain the grid.

[0018] As a preferred technical solution of the present invention, the thickness of the aluminum strip raw material is 0.4-0.8mm, and the thickness of the lead strip raw material is 0.5-0.7mm.

[0019] As a preferred technical solution of the present invention, in step three, the heating temperature is 1000℃~1100℃ and held for 10~15 seconds.

[0020] As a preferred technical solution of the present invention, an inert protective gas is continuously introduced during the heating process.

[0021] As a preferred technical solution of the present invention, a pressing device is used for processing. The pressing device includes a conveying device, a heating device, and a rolling device. The conveying device includes an upper conveying mechanism, a middle conveying mechanism, and a lower conveying mechanism. The upper and lower conveying mechanisms are both used to convey lead strip, and the middle conveying mechanism is used to convey aluminum strip. The strip flows from the conveying device to the rolling device via the heating device, which is located at the strip outlet of the middle conveying mechanism.

[0022] As a preferred embodiment of the present invention, the roller pressing device includes an upper pressure roller and a lower pressure roller. Shaft seats are installed at both ends of the upper pressure roller and both ends of the lower pressure roller, and the shaft seats are slidably engaged with the frame. The upper and lower pressure rollers are driven by separate drive motors. An adjusting cylinder is provided between the upper and lower pressure rollers to adjust the distance between them. The cylinder body is mounted on the lower pressure roller, and a chain is connected to the telescopic end of the adjusting cylinder. The end of the chain away from the adjusting cylinder is fixedly connected to the upper pressure roller. The drive motor is connected to both the upper and lower pressure rollers via universal joints.

[0023] As a preferred technical solution of the present invention, the heating device adopts an induction coil heating device.

[0024] As a preferred technical solution of the present invention, a traction device is also provided between the heating device and the rolling device.

[0025] The present invention has the following beneficial effects:

[0026] This invention employs a pressing method to bond lead strips to both surfaces of an aluminum strip, followed by stamping and cutting to produce a composite grid, significantly reducing the complexity of the aluminum-lead composite grid fabrication process. Simultaneously, to overcome technical barriers, an induction coil is used to preheat the aluminum strip before pressing. This preheating process reduces alumina at high temperatures, decreasing the amount of alumina adhering to the aluminum strip surface, which helps reduce battery internal resistance and lead-aluminum connectivity. Furthermore, heating brings the aluminum strip surface closer to a molten state, reducing its hardness and facilitating the pressing of the aluminum and lead strips. The pressed strip is less prone to detachment, resulting in high grid stability.

[0027] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a flowchart of the lead-acid battery grid manufacturing method of the present invention;

[0030] Figure 2 This is a schematic diagram of the pressing equipment of the present invention;

[0031] Figure 3 This is a top view of the pressing device of the present invention;

[0032] Figure 4This is a cross-sectional view of the pressing device of the present invention;

[0033] Figure 5 This is a schematic diagram of the roller pressing device;

[0034] Figure 6 This is a schematic diagram and a partially enlarged schematic diagram of the structure of the plate grid of the present invention;

[0035] The attached diagram lists the components represented by each number as follows:

[0036] 1-Roller pressing device, 101-Upper roller, 102-Lower roller, 103-Drive motor, 104-Universal shaft, 105-Adjusting cylinder, 106-Chain, 107-Frame, 2-Conveying device, 201-Upper conveying mechanism, 202-Middle conveying mechanism, 203-Lower conveying mechanism, 3-Heating device, 4-Traction device. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] In the description of this invention, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inner", "around", etc., which indicate orientation or positional relationship, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this invention.

[0039] Secondary lead-acid batteries are currently the most produced and marketed type of battery due to their safety, reliability, low cost, and the fact that almost all used batteries can be recycled. However, their low energy density (approximately 30–40 kW / kg) and relatively low charge-discharge cycle life limit their application in many fields. Therefore, improving their energy / power density and cycle life (especially cycle life under high-rate partial charge / discharge conditions) is an important direction for current research and development. In view of this, developing advanced technologies such as lightweight lead grids, bipolar plate structures, and lead-carbon electrodes is essential.

[0040] Generally, improving the energy density of lead-acid batteries to achieve "lightweight and high energy" is an important criterion for judging the advancement of lead-acid battery technology. Among these criteria, grid lightweighting plays a crucial role in reducing the weight of lead-acid batteries. The main measure for grid lightweighting is to replace lead grids with low-density, lead-free conductive materials. The lead-free grid material must be able to support the active material, ensure sufficient contact area between the active material and the electrolyte, minimize the battery's internal resistance, and remain stable in the electrolyte. The selection of lead-free grid materials has a significant impact on the performance and lifespan of lead-acid batteries.

[0041] Aluminum-based grid materials are inexpensive, low-density, and high-strength. Plating copper, zinc, lead, and tin alloys onto aluminum-based grids of various shapes can reduce grid weight. However, the main limitation of aluminum-based grids is that aluminum is highly reactive and easily oxidized. The formation of surface alumina makes it difficult for aluminum and lead to bond, affecting battery efficiency. Currently, the most widely used method is hot-melt lead impregnation, but this method involves numerous and complex pretreatment steps, resulting in high production costs and hindering practical applications. Therefore, this embodiment proposes a manufacturing method for lead-acid battery grids suitable for large-scale industrial production of aluminum-based grids.

[0042] It is worth noting that during the charging and discharging process of the battery, the aluminum substrate grid is in a high potential state when used as the positive electrode grid and is easily corroded, so it cannot play an effective role. Therefore, it is more suitable as the negative electrode plate of lead-acid batteries.

[0043] Please see Figure 1 As shown, the manufacturing method of the lead-acid battery grid in this embodiment includes the following steps:

[0044] Step 1: Press aluminum strip and lead strip raw materials of a set thickness using continuous casting and rolling equipment.

[0045] The specific processing equipment and technology can be referenced from the scheme disclosed in patent publication number CN206921925U. In this embodiment, since it is used to produce the negative electrode plate of lead-acid batteries, the total thickness of the grid should be controlled between 1.2-1.5mm. The required thickness of the aluminum strip raw material is 0.6mm, and the thickness of the lead strip raw material is also 0.6mm.

[0046] Step 2: Use a pressing device to composite the aluminum strip and lead strip raw materials. First, use conveyor device 2 to transport the raw materials.

[0047] Please see Figures 2-4 As shown, the conveying device 2 includes an upper conveying mechanism 201, a middle conveying mechanism 202, and a lower conveying mechanism 203. The upper conveying mechanism 201 and the lower conveying mechanism 203 are both used to convey lead strips, and the middle conveying mechanism 202 is used to convey aluminum strips. The conveying mechanism is preferably a roller-type powered conveyor line.

[0048] Step 3: Use heating device 3 to heat the aluminum strip.

[0049] Heating device 3 employs an induction coil and is located at the outlet end of the intermediate conveyor mechanism 202. When the lead strip exits from the intermediate conveyor mechanism 202, it passes through the induction coil. Under the action of the induction coil, the aluminum can be rapidly heated. Because aluminum has high electrical and thermal conductivity, it can guide the current in the induction coil to its surface, generating an induced current and rapidly heating the aluminum.

[0050] The heating temperature is 1000℃~1100℃ and held for 10~15 seconds. On the one hand, heating reduces the alumina at high temperature, decreasing the amount of alumina adhering to the aluminum strip surface, which helps reduce the battery's internal resistance and the connectivity of subsequent lead-aluminum lamination. On the other hand, heating brings the aluminum strip surface closer to a molten state, reducing its hardness and making it more conducive to the lamination of the aluminum strip and lead strip. After lamination, it is less likely to detach, resulting in high grid stability.

[0051] In addition, an inert protective gas, such as nitrogen, should be continuously introduced during the heating process to reduce the re-oxidation of elemental aluminum at high temperatures.

[0052] Step 4: Use traction device 4 to stack lead strip-aluminum strip-lead strip and pull it towards roller pressing device 1.

[0053] Step 5: After the lead strip-aluminum strip-lead strip are stacked, they enter the roller pressing device 1 for pressing.

[0054] Please see Figure 5 As shown, the roller pressing device 1 includes an upper roller 101 and a lower roller 102. Both ends of the upper roller 101 and both ends of the lower roller 102 are equipped with bearing seats. The bearing seats can slide up and down along the frame 107 via sliders and slide rails to adjust the distance between the upper roller 101 and the lower roller 102, i.e., to adjust the thickness of the pressed strip. The upper roller 101 and the lower roller 102 are driven by separate drive motors 103, which are fixed by a fixed bracket. The drive motors 103 are connected to both the upper roller 101 and the lower roller 102 via universal joints 104 to accommodate the up and down sliding of the upper roller 101 and the lower roller 102. The distance between the upper pressure roller 101 and the lower pressure roller 102 is adjusted by the adjusting cylinder 105. The cylinder body of the adjusting cylinder 105 is installed on the lower pressure roller 102. The telescopic end of the adjusting cylinder 105 is connected to a chain 106. The end of the chain 106 away from the adjusting cylinder 105 is fixedly connected to the upper pressure roller 101.

[0055] When the lead strip-aluminum strip-lead strip are stacked and enter the gap between the upper pressure roller 101 and the lower pressure roller 102, the adjusting cylinder 105 contracts, causing the upper pressure roller 101 and the lower pressure roller 102 to press the material strip tightly and set the thickness of the pressed material strip. Then, the drive motor 10 is started, and after being rolled by the upper pressure roller 101 and the lower pressure roller 102, the composite material strip is obtained.

[0056] Step Six: Use a stamping machine to stamp the composite strip, removing waste and scrap to obtain the grid strip. Finally, use a cutting machine to cut the grid strip to obtain the grid.

[0057] The plate grid obtained by stamping through the above steps is as follows: Figure 6 As shown, the grid includes an aluminum-based mesh layer and a lead-based mesh layer laminated to both surfaces of the aluminum-based mesh layer. After the above steps, because aluminum is harder than lead, the lead strip deforms more after lamination. The thickness of the aluminum-based mesh layer is approximately 0.5 mm, the thickness of the lead-based mesh layer is approximately 0.4 mm, the total grid thickness is approximately 1.3 mm, and the total weight is approximately 38 grams. Compared to a pure lead grid, the weight of a single negative grid is reduced by approximately 8-10 grams, and the total battery weight can be reduced by 100-120 grams. Furthermore, it reduces the battery's internal resistance and deformation, resulting in a significant weight reduction effect.

[0058] Furthermore, in this embodiment, the lead-based mesh layer can be one of lead-tin alloy, lead-antimony alloy, lead-calcium alloy, or lead-rare earth alloy. Lead-calcium alloy is preferred because it offers stable performance and requires no maintenance during battery operation.

[0059] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0060] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for manufacturing a lead-acid battery grid, characterized in that, Includes the following steps: Step 1: Press aluminum strip and lead strip raw materials of a set thickness using continuous casting and rolling equipment; Step 2: Convey the raw materials in the order of upper lead strip, middle aluminum strip, and lower lead strip; Step 3: Heat the aluminum strip; during the heating process, continuously introduce inert protective gas; Step 4: Stack and press lead strip-aluminum strip-lead strip in this order to form a composite strip; Step 5: Use stamping equipment to stamp the composite strip into a grid strip; Step 6: Use a cutting device to cut the grid strip to obtain the grid.

2. The method for manufacturing a lead-acid battery grid according to claim 1, characterized in that, The lead-acid battery grid includes an aluminum-based mesh layer and a lead-based mesh layer pressed onto both surfaces of the aluminum-based mesh layer. The thickness of the aluminum-based mesh layer is 0.4-0.8 mm, and the thickness of the lead-based mesh layer is 0.3-0.6 mm.

3. The method for manufacturing a lead-acid battery grid according to claim 2, characterized in that, The lead-based mesh layer is made of one of the following: lead-tin alloy, lead-antimony alloy, lead-calcium alloy, or lead-rare earth alloy.

4. The method for manufacturing a lead-acid battery grid according to claim 1, characterized in that, The thickness of the aluminum strip raw material is 0.4-0.8 mm, and the thickness of the lead strip raw material is 0.5-0.7 mm.

5. The method for manufacturing a lead-acid battery grid according to claim 1, characterized in that, In step three, the heating temperature is 1000℃~1100℃, and the temperature is maintained for 10~15 seconds.

6. The method for manufacturing a lead-acid battery grid according to claim 1, characterized in that, The processing is carried out using a pressing device, which includes: a conveying device (2), a heating device (3), and a roller pressing device (1). The conveying device (2) includes an upper conveying mechanism (201), a middle conveying mechanism (202) and a lower conveying mechanism (203). The upper conveying mechanism (201) and the lower conveying mechanism (203) are both used to convey lead strips, and the middle conveying mechanism (202) is used to convey aluminum strips. The material belt flows from the conveying device (2) to the rolling device (1) via the heating device (3), and the heating device (3) is located at the material belt outlet of the middle conveying mechanism (202).

7. A method for manufacturing a lead-acid battery grid according to claim 6, characterized in that, The roller pressing device (1) includes an upper pressing roller (101) and a lower pressing roller (102). Both ends of the upper pressing roller (101) and both ends of the lower pressing roller (102) are equipped with bearing seats, which are slidably engaged with the frame (107). The upper pressure roller (101) and the lower pressure roller (102) are driven by separate drive motors (103); An adjusting cylinder (105) is provided between the upper pressure roller (101) and the lower pressure roller (102) to adjust the distance between them. The cylinder body of the adjusting cylinder (105) is installed on the lower pressure roller (102). A chain (106) is connected to the telescopic end of the adjusting cylinder (105). The end of the chain (106) away from the adjusting cylinder (105) is fixedly connected to the upper pressure roller (101). The drive motor (103) is connected to the upper pressure roller (101) and the lower pressure roller (102) via a universal joint (104).

8. A method for manufacturing a lead-acid battery grid according to claim 7, characterized in that, The heating device (3) is an induction coil heating device.

9. A method for manufacturing a lead-acid battery grid according to claim 8, characterized in that, A traction device (4) is also provided between the heating device (3) and the roller pressing device (1).

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