Extremely simple cylindrical battery and assembly process

Abstract

The invention discloses an extremely-simple cylindrical battery and an assembly process, and relates to the technical field of cylindrical batteries, the extremely-simple cylindrical battery comprises a steel shell, a positive electrode cover plate, a roll core, a rubber ring and a sealing aluminum sheet, the steel shell and the positive electrode cover plate form sealing combination through the rubber ring, and positive and negative electrode lugs of the roll core are electrically connected with the positive electrode cover plate and the steel shell respectively; and the sealing aluminum sheet covers and seals the positive electrode lead-out area of the cover plate. And a structural connection system with an electrical conduction function and sealing reliability is formed among the five components, so that an integrated and highly integrated cylindrical battery structural form is formed. According to the invention, positive and negative collector plates in a traditional cylindrical battery structure are cancelled, and the tabs are respectively and directly connected with the steel shell and the positive cover plate, so that the welding frequency is obviously reduced, the assembly process is simplified, the production efficiency is improved, the liquid leakage and self-discharge risks are reduced, and the structural sealing property and the electrical connection reliability are improved; therefore, the integrated technical effects of simpler structure, more efficient manufacturing and more stable battery performance are achieved.

Description

Technical Field

[0001] This invention relates to the field of cylindrical battery technology, specifically to a minimally sized cylindrical battery and its assembly process. Background Technology

[0002] Currently, steel-cased cylindrical lithium-ion batteries are widely used in power batteries, energy storage batteries, and other fields. Their typical structure usually includes multiple components such as a cell winding body, a positive current collector, a negative current collector, a steel casing, an aluminum positive electrode cover, rubber rings, and sealing studs. In existing technologies, to achieve conductive connection between the tabs and external leads, a "tab-current collector-cover / casing" structural path is typically used, requiring multiple solder joints to establish the current path. Specifically, the positive tab must first be connected to the positive current collector, and then the current collector is welded to the positive electrode cover; the negative tab also needs to be connected to the steel casing via the negative current collector.

[0003] While the above structure achieves functional completeness to a certain extent, it has the following significant problems in actual production: The welding process is complex: each of the positive and negative electrodes requires two welding operations, totaling at least four laser welding operations, which seriously affects the production line cycle time and manufacturing efficiency. Complex manufacturing process and low yield: Multi-layer metal structures are prone to welding deformation and poor soldering, which can lead to poor conductivity, uneven internal resistance or early failure. Excessive welding dust and abnormal self-discharge: During the welding process, metal particles are easily deposited on the electrode or casing, affecting the static performance of the battery. High risk of leakage: The more welds there are, the higher the potential risk of liquid leakage in the structure, especially at the interface between the manifold weld and the cover plate. Bulky structure and high cost: As an additional structural component, the collector not only increases the cost of material procurement and assembly, but also occupies shell space and reduces the unit energy density.

[0004] In addition, Chinese patent CN117317341A discloses a large cylindrical battery cell structure and processing technology. By improving the traditional negative electrode current collector into a shell, and changing the traditional two-point welding method to the existing method of welding the positive electrode current collector in one step, the flattening process and long welding needle resistance welding are abandoned and replaced by electrode tab pressing penetration welding. Although this avoids the smoke and dust generated during the welding of the traditional negative electrode current collector and positive electrode current collector from entering the cell, and meets the basic electrical connection and structural packaging requirements, there are still problems such as complex manufacturing process, poor reliability and high material cost. There is an urgent need for technical improvements in structural simplification and process optimization. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a simplified cylindrical battery and assembly process to solve the problems mentioned in the background section.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a simplified cylindrical battery, comprising a steel casing, a positive electrode cover, a core, a rubber ring, and a sealing aluminum sheet; The steel shell serves as the battery casing assembly, and the negative electrode tab inside the winding core is electrically connected to the steel shell. The positive electrode cover is located at the opening end of the steel shell, and its body and the steel shell are connected by a rubber ring to form a structural sealing fit. The rubber ring is located between the opening of the steel shell and the positive electrode cover. The positive electrode tab of the core extends upward and is electrically connected to the conductive area of ​​the positive electrode cover plate, while the negative electrode tab of the core extends downward and forms a negative electrode conduction path with the inner wall of the steel shell. The sealing aluminum sheet covers the central conductive part of the positive electrode cover and seals the positive electrode lead-out area of ​​the cover, serving as the outermost sealing component of the positive electrode structure.

[0007] A simplified assembly process for a cylindrical battery, based on the aforementioned simplified cylindrical battery assembly, includes the following specific steps: S1. Core inserted into casing; The pre-wound battery cell is placed inside the steel shell, forming a preliminary positioning relationship between the core and the steel shell; S2, steel shell grooving; The steel shell is plastically rolled at the open end by a grooving device to form an annular limiting groove. S3, negative electrode penetration soldering; Laser penetration welding process is used to directly weld the negative electrode tab on the negative end face of the core to the bottom or inner wall of the steel shell, so that the negative electrode tab and the steel shell form a reliable electrical connection. S4. Insert the positive electrode cover; Insert the aluminum positive electrode cover into the opening end of the steel shell, aligning its lower edge with the groove position, with the conductive part of the positive electrode cover extending inward, reserved for subsequent positive electrode tab welding; S5, crouch seal; The positive electrode cover plate is pressed into the groove of the steel shell by a squatting sealing device, and the opening of the steel shell is turned inward at the same time, so that the positive electrode cover plate and the steel shell form a mechanical limiting connection relationship, and the positive electrode cover plate is firmly pressed in the state of rubber ring compression to ensure the initial sealing formation. S6, Positive electrode penetration soldering; Lead out the positive electrode tab from the positive end face of the core and align it with the conductive area of ​​the positive electrode cover plate. Use laser penetration welding to penetrate and weld the tab to the conductive part in the center of the positive electrode cover plate to form the positive electrode output path of the battery. S7, One-time injection; With the positive electrode cover plate having an injection hole, a set amount of electrolyte is injected into the steel shell through a vacuum injection process. S8, High-temperature standing; Place the electrolyte-filled battery cell at a set temperature to allow the electrolyte to fully wet the electrode sheets and complete the wetting distribution. S9, transformation; By applying constant current and constant voltage electrochemical treatment to the battery cell through an external power source, the positive and negative electrode plates and the electrolyte undergo the first controllable reaction to form a stable SEI film layer. S10, secondary injection; Based on the difference between the cell's liquid absorption loss and structural capacity after the formation process, a supplementary liquid injection operation is performed; S11, Sealing nail welding; The prefabricated sealing aluminum sheet is placed above the central injection hole of the positive electrode cover plate and welded to the positive electrode cover plate by laser sealing welding. S12, capacity division; The welded and sealed battery cells are placed in a capacity testing and grading device for capacity testing and classification.

[0008] To further optimize this technical solution, in step S1, the positive and negative end faces of the core are flattened using a flattening process or laser-cut tabs / tab stacking process. The core diameter is 44-44.7mm. After flattening the positive and negative tabs, the exposed aluminum height of the positive electrode is 1.0mm-2.0mm, and the exposed copper height of the negative electrode is 0.6-1.0mm. The exposed aluminum position of the positive electrode is covered with insulating tape, and the width of the tape covering the positive end face is 3-5mm.

[0009] To further optimize this technical solution, in step S2, the rubber ring is fixed by the annular limiting groove of the groove, thereby forming insulation between the positive electrode cover plate and the steel shell. The groove uses a 1.6mm roller cutter, the groove depth is 2.1-2.4mm, and the shoulder height of the steel shell after grooving is 5.2-6.0mm.

[0010] To further optimize this technical solution, in step S3, the steel shell and the negative end face of the core are directly connected by penetration welding. The negative electrode penetration welding head is continuously laser welded, and the welding is elliptical. During welding, the negative end face must be in contact with the bottom plane of the steel shell. The maximum outer diameter of the elliptical area of ​​the welding area is 11-15mm, the minimum outer diameter is 6-10mm, the welding process is continuous welding, the weld width is 1mm, the pull-out force after welding is ≥20N, and the residual area of ​​the weld point is ≥85%.

[0011] To further optimize this technical solution, in step S5, the squatting seal is performed with 3-4 sealing operations. The 1-2 squatting seals are used to plasticize the shell opening, and the 3-4 squatting seals are used to solidify the shell shoulder height and shape the shell. After squatting seal, the steel shell shoulder height is 3.0-3.8mm, ensuring that the deformation of the rubber ring is 30%-55%.

[0012] To further optimize this technical solution, in step S6, the positive electrode cover plate adopts a recessed boss design, the positive electrode cover plate is in contact with the positive end face of the core, the positive electrode cover plate and the core form a conductivity, and the positive electrode penetration welding head adopts an elliptical welding; the maximum outer diameter of the elliptical welding area is 11-15mm, the minimum outer diameter is 6-10mm, continuous welding is adopted during the welding process, the weld width is 1mm, the pull-out force after welding is ≥20N, and the residual area of ​​the weld point is ≥85%.

[0013] To further optimize this technical solution, in step S8, the temperature is set to 45-60℃, and the plate is left to stand in a constant temperature environment for 12-24 hours to allow the electrolyte to fully react and wet the electrode, and to remove air bubbles.

[0014] To further optimize this technical solution, in step S9, the battery is formed using a constant current and constant voltage method: after constant current charging to the rated voltage at 0.5C, constant voltage charging is applied until the cutoff current is reached, and an SEI film is generated during the reaction process; after formation, the voltage plateau, leakage state, and initial capacity value should be detected to identify early defects.

[0015] To further optimize this technical solution, in step S10, a supplementary liquid injection operation is performed on the slightly deficient liquid cells after formation, and the amount of liquid injection does not exceed 5-10% of the amount of liquid injected in the first injection.

[0016] Compared with the prior art, the present invention provides a simplified cylindrical battery and assembly process, which has the following advantages: This minimalist cylindrical battery and its assembly process eliminates the positive and negative current collectors in the traditional cylindrical battery structure. Instead, it uses tabs that are directly connected to the steel casing and the positive electrode cover, respectively. This not only significantly reduces the number of welding operations and simplifies the assembly process, improving production efficiency, but also reduces material costs and welding dust generation, decreases the risk of leakage and self-discharge, and improves structural sealing and electrical connection reliability. As a result, it achieves a more concise structure, more efficient manufacturing, and more stable battery performance. Attached Figure Description

[0017] 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 accompanying 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.

[0018] Figure 1 This is a schematic diagram of the assembly process of a simplified cylindrical battery proposed in this invention. Figure 2 This is an exploded view of the structure of a minimally sized cylindrical battery proposed in this invention. Figure 3This is a schematic diagram of the assembled structure of a minimalist cylindrical battery proposed in this invention.

[0019] In the diagram: 1. Sealing aluminum sheet; 2. Positive electrode cover plate; 3. Rubber ring; 4. Core; 5. Steel shell. Detailed Implementation

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0021] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0022] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.

[0023] Example 1: Reference Figures 1-3 This is the first embodiment of the present invention, which provides a minimalist cylindrical battery, including a steel shell 5, a positive electrode cover plate 2, a core 4, a rubber ring 3, and a sealing aluminum sheet 1.

[0024] The steel casing 5 serves as the battery outer shell assembly, and its body also functions as the lead-out point for the negative electrode. The negative electrode tab inside the core 4 is electrically connected to the steel casing 5. This connection allows the steel casing 5 to form the negative terminal output of the battery, thereby enabling current collection from the negative electrode through the external structure.

[0025] The positive electrode cover plate 2 is located at the open end of the steel shell 5, and its body and the steel shell 5 are structurally sealed together by a rubber ring 3. The rubber ring 3 is located between the opening of the steel shell 5 and the positive electrode cover plate 2 to achieve an effective gas-tight structure after the positive electrode cover plate 2 is assembled into the shell, thereby forming a reliable interface seal and blocking the channels for electrolyte evaporation and external gas permeation.

[0026] The core 4 is the core energy storage unit inside the battery. The positive electrode tab of the core 4 extends upward and is electrically connected to the conductive area of ​​the positive electrode cover 2, allowing the positive current to be drawn out through the positive electrode cover 2. The negative electrode tab of the core 4 extends downward and forms a negative electrode conductive path with the inner wall of the steel shell 5, thus completing the electrical path between the two poles of the cell.

[0027] The sealing aluminum sheet 1 covers the central conductive part of the positive electrode cover plate 2 and is used to seal the positive electrode lead-out channel. It is the outermost sealing component of the positive electrode structure. The sealing aluminum sheet 1 and the positive electrode cover plate 2 form a fixed and sealed connection, which further ensures the airtightness of the central area of ​​the positive electrode cover plate 2 and prevents electrolyte leakage or intrusion of external contaminants.

[0028] In summary, the steel shell 5 and the positive electrode cover 2 are sealed together by the rubber ring 3. The positive and negative electrode tabs of the core 4 are electrically connected to the positive electrode cover 2 and the steel shell 5, respectively. The sealing aluminum sheet 1 covers and seals the positive electrode lead-out area of ​​the positive electrode cover 2. The five components form a structural connection system with electrical conductivity and reliable sealing, constituting an integrated, highly integrated cylindrical battery structure.

[0029] The assembly of the aforementioned minimalist cylindrical battery includes the following specific steps: S1. Core inserted into casing; The pre-wound battery cell is placed inside the steel shell, forming a preliminary positioning relationship between the core and the steel shell.

[0030] This step requires that the tabs be of uniform length, with the negative tab facing down and aligned with the bottom of the steel shell, and the positive tab facing up and reserved at the opening end of the steel shell.

[0031] The positive and negative terminals of the core are flattened using a flattening process or laser-cut / stacked tabs to ensure flatness. The core diameter is 44-44.7mm. After flattening the positive and negative tabs, the exposed aluminum height of the positive electrode is 1.0mm-2.0mm, and the exposed copper height of the negative electrode is 0.6-1.0mm. The exposed aluminum position of the positive electrode is covered with insulating tape. The tape covering the positive terminal is 3-5mm wide to prevent short circuit between the positive electrode and the steel shell.

[0032] S2, steel shell grooving; The steel shell opening is plastically rolled using a grooving device to form an annular limiting groove, preventing the core from wobbling inside the shell and facilitating through-welding of the positive and negative electrodes (preventing weld abnormalities during through-welding). This groove is also used to subsequently fix the rubber ring and positive electrode cover, providing a stable structural foundation for the sealing structure.

[0033] The rubber ring is fixed by the annular limiting groove of the grooving, thereby forming an insulation between the positive electrode cover plate and the steel shell, ensuring that the positive and negative electrodes will not be short-circuited. The grooving uses a 1.6mm roller cutter, the grooving depth is 2.1-2.4mm, and the shoulder height of the steel shell after grooving is 5.2-6.0mm.

[0034] S3, negative electrode penetration soldering; Laser penetration welding is used to directly weld the negative electrode tab on the negative end face of the core to the bottom or inner wall of the steel shell, forming a reliable electrical connection between the negative electrode tab and the steel shell. This connection establishes the negative current output path of the battery and also provides structural stability.

[0035] The steel shell and the negative end face of the core are directly connected by through welding. The negative electrode through welding head is continuously laser welded and the welding is elliptical. During welding, the negative end face must be in contact with the bottom plane of the steel shell. The maximum outer diameter of the elliptical area of ​​the welding area is 11-15mm and the minimum outer diameter is 6-10mm. Continuous welding is used during the welding process. The weld width is 1mm. The pull-out force after welding is ≥20N and the residual area of ​​the weld point is ≥85%.

[0036] S4. Insert the positive electrode cover; Insert the aluminum positive electrode cover into the opening of the steel shell, aligning its lower edge with the groove position. The conductive part of the positive electrode cover extends inward, reserved for subsequent positive electrode tab welding.

[0037] At the same time, ensure that the fit clearance between the edge of the cover plate and the steel shell meets the requirements for subsequent treading and sealing.

[0038] S5, crouch seal; The positive electrode cover is pressed into the groove of the steel shell by a squatting sealing device, while the opening of the steel shell is turned inward to form a mechanical limiting connection between the positive electrode cover and the steel shell. The positive electrode cover is firmly pressed under the compression state of the rubber ring to ensure the initial sealing and forming.

[0039] The squatting seal uses 3-4 sealing processes. The first 1-2 squatting seals are used to shape the shell opening, and the 3-4 squatting seals are used to solidify the shell shoulder height and shape the shell. After squatting seal, the steel shell shoulder height is 3.0-3.8mm, ensuring that the rubber ring deformation is 30%-55%.

[0040] S6, Positive electrode penetration soldering; Lead out the positive electrode tab from the positive end face of the core and align it with the conductive area of ​​the positive electrode cover. Use laser penetration welding to weld the tab through to the conductive part in the center of the positive electrode cover, forming the positive electrode output path of the battery. After welding, ensure that the weld is firm, has good conductivity, and is free of spatter or particle residue.

[0041] The positive electrode cover plate adopts a recessed boss design, and the positive electrode cover plate fits with the positive end face of the core. The positive electrode cover plate and the core form a conductivity. The positive electrode penetration welding head adopts an elliptical welding. The maximum outer diameter of the elliptical welding area is 11-15mm, and the minimum outer diameter is 6-10mm. Continuous welding is adopted during the welding process, the weld width is 1mm, the pull-out force after welding is ≥20N, and the residual area of ​​the weld point is ≥85%.

[0042] S7, One-time injection; With the positive electrode cover plate having an injection hole, a set amount of electrolyte is injected into the steel shell through a vacuum injection process.

[0043] The liquid injection volume must meet the design capacity requirements and be precisely controlled in conjunction with the electrode liquid absorption rate and safety gap.

[0044] S8, High-temperature standing; The electrolyte-filled battery cell is placed at a set temperature to allow the electrolyte to fully wet the electrode and complete the wetting distribution, thereby improving the uniformity of the subsequent electrochemical reaction.

[0045] Set the temperature to 45-60℃ and let it stand in a constant temperature environment for 12-24 hours to allow the electrolyte to fully react and wet the electrode, and to remove air bubbles.

[0046] S9, transformation; By applying constant current and constant voltage electrochemical treatment to the battery cell using an external power source, the positive and negative electrodes and the electrolyte undergo a first controlled reaction, forming a stable SEI film layer, which improves the cell's safety and cycle life. The formation process parameters are set according to the cell capacity and design requirements.

[0047] The battery is formed using a constant current and constant voltage method: after constant current charging to the rated voltage, constant voltage charging is applied until the cutoff current is reached, and an SEI film is generated during the reaction process; after formation, the voltage plateau, leakage state and initial capacity value should be detected to identify early defects.

[0048] S10, secondary injection; Based on the difference between the cell's electrolyte absorption loss and structural capacity after the formation process, a supplementary electrolyte injection operation is performed. This further improves the uniformity of electrolyte distribution and ensures efficient capacity release in the later stages. The secondary electrolyte injection can be performed through micropores or temporary openings.

[0049] For cells with slight electrolyte loss after formation, perform supplementary electrolyte injection. The amount of electrolyte added should not exceed 5-10% of the amount injected the first time, to ensure consistency of internal resistance and no air residue in the subsequent sealing cavity.

[0050] S11, Sealing nail welding; The prefabricated sealing aluminum sheet is placed above the central injection hole of the positive electrode cover plate and then welded to the positive electrode cover plate using laser sealing welding.

[0051] Welding should form an airtight, continuous weld, sealing all openings to ensure the overall airtightness of the battery cell.

[0052] S12, capacity division; The welded and sealed battery cells are placed in a capacity testing and grading device for capacity testing and classification.

[0053] Based on parameters such as capacity, internal resistance, and voltage, the battery cells are classified into different grades with a pass rate of no less than 95%, in order to facilitate subsequent modular assembly or shipment management.

[0054] This assembly process is based on a minimalist structure. By eliminating the positive and negative current collectors, the positive and negative electrode tabs are directly connected to the steel shell and cover plate, significantly reducing welding processes and structural complexity. Combined with roller groove positioning, foot sealing press fitting, and sealing welding, a highly reliable closed-loop structure is formed, improving manufacturing cycle time, reducing failure rate and material costs. It is suitable for high-energy-density, high-volume production lines of cylindrical batteries.

[0055] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A minimalist cylindrical battery, characterized in that, Includes steel shell, positive electrode cover plate, core, rubber ring and sealing aluminum sheet; The steel shell serves as the battery casing assembly, and the negative electrode tab inside the winding core is electrically connected to the steel shell. The positive electrode cover is located at the opening end of the steel shell, and its body and the steel shell are connected by a rubber ring to form a structural sealing fit. The rubber ring is located between the opening of the steel shell and the positive electrode cover. The positive electrode tab of the core extends upward and is electrically connected to the conductive area of ​​the positive electrode cover plate, while the negative electrode tab of the core extends downward and forms a negative electrode conduction path with the inner wall of the steel shell. The sealing aluminum sheet covers the central conductive part of the positive electrode cover and seals the positive electrode lead-out area of ​​the cover, serving as the outermost sealing component of the positive electrode structure.

2. A simplified assembly process for a cylindrical battery, based on the simplified cylindrical battery described in claim 1, characterized in that, The specific steps include the following: S1. Core inserted into casing; The pre-wound battery cell is placed inside the steel shell, forming a preliminary positioning relationship between the core and the steel shell; S2, steel shell grooving; The steel shell is plastically rolled at the open end by a grooving device to form an annular limiting groove. S3, negative electrode penetration soldering; Laser penetration welding process is used to directly weld the negative electrode tab on the negative end face of the core to the bottom or inner wall of the steel shell, so that the negative electrode tab and the steel shell form a reliable electrical connection. S4. Insert the positive electrode cover; Insert the aluminum positive electrode cover into the opening end of the steel shell, aligning its lower edge with the groove position, with the conductive part of the positive electrode cover extending inward, reserved for subsequent positive electrode tab welding; S5, crouch seal; The positive electrode cover plate is pressed into the groove of the steel shell by a squatting sealing device, and the opening of the steel shell is turned inward at the same time, so that the positive electrode cover plate and the steel shell form a mechanical limiting connection relationship, and the positive electrode cover plate is firmly pressed in the state of rubber ring compression to ensure the initial sealing formation. S6, Positive electrode penetration soldering; Lead out the positive electrode tab from the positive end face of the core and align it with the conductive area of ​​the positive electrode cover plate. Use laser penetration welding to penetrate and weld the tab to the conductive part in the center of the positive electrode cover plate to form the positive electrode output path of the battery. S7, One-time injection; With the positive electrode cover plate having an injection hole, a set amount of electrolyte is injected into the steel shell through a vacuum injection process. S8, High-temperature standing; Place the electrolyte-filled battery cell at a set temperature to allow the electrolyte to fully wet the electrode sheets and complete the wetting distribution. S9, transformation; By applying constant current and constant voltage electrochemical treatment to the battery cell through an external power source, the positive and negative electrode plates and the electrolyte undergo the first controllable reaction to form a stable SEI film layer. S10, secondary injection; Based on the difference between the cell's liquid absorption loss and structural capacity after the formation process, a supplementary liquid injection operation is performed; S11, Sealing nail welding; The prefabricated sealing aluminum sheet is placed above the central injection hole of the positive electrode cover plate and welded to the positive electrode cover plate by laser sealing welding. S12, capacity division; The welded and sealed battery cells are placed in a capacity testing and grading device for capacity testing and classification.

3. The assembly process of a simplified cylindrical battery according to claim 2, characterized in that, In step S1, the positive and negative end faces of the core are flattened using a flattening process or laser-cut tabs / tab stacking process. The core diameter is 44-44.7mm. After flattening the positive and negative tabs, the exposed aluminum height of the positive electrode is 1.0mm-2.0mm, and the exposed copper height of the negative electrode is 0.6-1.0mm. The exposed aluminum position of the positive electrode is covered with insulating tape, and the width of the tape covering the positive end face is 3-5mm.

4. The assembly process of a simplified cylindrical battery according to claim 2, characterized in that, In step S2, the rubber ring is fixed by the annular limiting groove of the groove, thereby insulating the positive electrode cover plate from the steel shell. The groove uses a 1.6mm roller cutter, the groove depth is 2.1-2.4mm, and the shoulder height of the steel shell after grooving is 5.2-6.0mm.

5. The assembly process of a simplified cylindrical battery according to claim 2, characterized in that, In step S3, the steel shell and the negative end face of the core are directly connected by penetration welding. The negative electrode penetration welding head is continuously laser welded and the welding is elliptical. During welding, the negative end face must be in contact with the bottom plane of the steel shell. The maximum outer diameter of the elliptical area of ​​the welding area is 11-15mm and the minimum outer diameter is 6-10mm. Continuous welding is used during the welding process. The weld width is 1mm. The pull-out force after welding is ≥20N and the residual area of ​​the weld point is ≥85%.

6. The assembly process of a simplified cylindrical battery according to claim 2, characterized in that, In step S5, the squatting seal is performed with 3-4 sealing operations. The 1-2 squatting seals are used to plasticize the shell opening, and the 3-4 squatting seals are used to solidify the shell shoulder height and shape the shell. After squatting seal, the steel shell shoulder height is 3.0-3.8mm, ensuring that the deformation of the rubber ring is 30%-55%.

7. The assembly process of a simplified cylindrical battery according to claim 2, characterized in that, In step S6, the positive electrode cover plate adopts a recessed boss design, the positive electrode cover plate is in contact with the positive end face of the core, the positive electrode cover plate and the core form a conductivity, and the positive electrode penetration welding head adopts elliptical welding; the maximum outer diameter of the elliptical welding area is 11-15mm, the minimum outer diameter is 6-10mm, the welding process adopts continuous welding, the weld width is 1mm, the pull-out force after welding is ≥20N, and the residual area of ​​the weld point is ≥85%.

8. The assembly process of a simplified cylindrical battery according to claim 2, characterized in that, In step S8, the temperature is set to 45-60℃, and the plate is left to stand in a constant temperature environment for 12-24 hours to allow the electrolyte to fully react and wet the electrode, and to remove air bubbles.

9. The assembly process of a simplified cylindrical battery according to claim 2, characterized in that, In step S9, the battery is formed using a constant current and constant voltage method: after being charged to the rated voltage at a constant current of 0.5C, it is then charged to the cutoff current at a constant voltage, and an SEI film is generated during the reaction process. After formation, the voltage plateau, leakage state, and initial capacity value should be detected to identify early defects.

10. The assembly process of a simplified cylindrical battery according to claim 2, characterized in that, In step S10, a supplementary electrolyte injection operation is performed on the slightly deficient electrolyte cells after formation, and the amount of electrolyte added does not exceed 5-10% of the amount of electrolyte injected in the first injection.

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