Cylindrical battery

Abstract

This application relates to the field of battery technology and discloses a cylindrical battery. The cylindrical battery has axial, radial, and circumferential dimensions and includes: a casing, one axial end of which is open; a cover plate disposed at the open end of the casing, the cover plate and the casing cooperating to define a receiving cavity, the cover plate including a plate body and a boss, the plate body having an axially penetrating terminal hole, the boss surrounding the outer periphery of the terminal hole; a terminal, passing through the terminal hole and extending into the receiving cavity; a cell assembly disposed within the receiving cavity, the cell assembly including a positive electrode, a negative electrode, and a separator, the positive electrode having an axially extending mounting hole, the negative electrode being ringed on the outside of the positive electrode and attached to the inner wall of the casing; and a current collector, at least a portion of which is disposed within the mounting hole and in contact with the positive electrode, the current collector being electrically connected to the terminal via a connecting wire, the current collector having multiple flow holes. Thus, the boss buffers the internal pressure of the cylindrical battery, helping to improve the discharge stability of the cylindrical battery.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a cylindrical battery. Background Technology

[0002] A cylindrical battery is an electrochemical device that converts chemical energy into electrical energy. Cylindrical batteries are widely used in digital cameras, lighting fixtures, water meters, and toys.

[0003] In related technologies, cylindrical batteries are affected by their own structure (such as the way the current collector and the positive electrode are matched, the way the electrode and the current collector are matched) and size, which causes a certain loss in the total amount of electricity that cylindrical batteries can release, thus limiting the realization of their high discharge performance potential. Utility Model Content

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. Therefore, one objective of this invention is to provide a cylindrical battery in which the current collector and terminals have high reliability in their fit, thus helping to reduce the internal resistance of the cylindrical battery.

[0005] According to an embodiment of this application, a cylindrical battery has axial, radial, and circumferential directions. The cylindrical battery includes: a casing, one axial end of which is open; a cover plate disposed at the open end of the casing, the cover plate and the casing cooperating to define a receiving cavity, the cover plate including a plate body and a boss, the plate body having an axially penetrating electrode hole, the boss surrounding the outer periphery of the electrode hole; an electrode post passing through the electrode hole and extending into the receiving cavity; a cell assembly disposed within the receiving cavity, the cell assembly including a positive electrode, a negative electrode, and a separator, the positive electrode having an axially extending mounting hole, the negative electrode being arranged around the outside of the positive electrode and attached to the inner wall of the casing, the separator being located between the positive electrode and the negative electrode; and a current collector, at least a portion of the current collector being disposed within the mounting hole and in contact with the positive electrode, the current collector being electrically connected to the electrode post via a connecting wire, the current collector having multiple flow holes.

[0006] According to the cylindrical battery of the present application embodiment, a certain gap is formed between the boss and the inner peripheral wall of the casing. The gap can be used as an air chamber to buffer the internal pressure, which helps to improve the discharge stability of the cylindrical battery.

[0007] According to some embodiments of this application, the boss protrudes axially toward the receiving cavity.

[0008] According to some embodiments of this application, in the axial direction, the thickness ratio H1 / H2 between the thickness H1 of the boss and the thickness H2 of the plate body ranges from 0.25 to 0.90.

[0009] According to some embodiments of this application, the thickness ratio H1 / H2 ranges from 0.5 to 0.6.

[0010] According to some embodiments of this application, in the axial direction, the thickness H1 of the boss ranges from 0.4mm to 0.9mm, and the thickness H2 of the plate body ranges from 1.0mm to 1.6mm.

[0011] According to some embodiments of this application, the cover plate further includes a connecting flange, which is disposed at the outer periphery of the plate body and protrudes away from and / or toward the receiving cavity, and the connecting flange is fixedly connected to the housing.

[0012] According to some embodiments of this application, in the axial direction, the maximum height of the connecting flange protruding from any surface of the plate body is a protrusion height of H3, the thickness of the plate body is H2, and the ratio range of the protrusion height H3 and the thickness H2 is 0.05-1.

[0013] According to some embodiments of this application, H3 / H2 is 0.1-0.5.

[0014] According to some embodiments of this application, the protrusion height H3 ranges from 0.05mm to 0.2mm, and the height of the shell ranges from 45mm to 65mm.

[0015] According to some embodiments of this application, in the axial direction, the end of the connecting flange away from the receiving cavity is flush with the open end of the housing; or, the end of the connecting flange away from the receiving cavity is lower than the open end of the housing.

[0016] According to some embodiments of this application, in the axial direction, at least one end of the manifold is provided with a reinforcing portion.

[0017] According to some embodiments of this application, in the axial direction, the first end of the collecting cylinder near the cover plate is provided with a first flange, and the reinforcing part includes the first flange; and / or, the second end of the collecting cylinder away from the cover plate is provided with a second flange, and the reinforcing part includes the second flange.

[0018] According to some embodiments of this application, in the axial direction of the cylindrical battery, the length of the first flange and the length of the second flange are the same; or, the length of the first flange is greater than the length of the second flange.

[0019] According to some embodiments of this application, the wall of the collector cylinder is a mesh structure, and the flow passage is a mesh.

[0020] According to some embodiments of this application, the flow collector includes a plurality of spaced-apart first ribs and a plurality of spaced-apart second ribs, each of the first ribs intersecting with a plurality of the second ribs and each of the second ribs intersecting with a plurality of the first ribs, and each flow hole is defined by the intersecting first ribs and second ribs.

[0021] According to some embodiments of this application, the thickness of the first rib and the thickness of the second rib are the same.

[0022] According to some embodiments of this application, the thickness of the manifold is in the range of 0.15mm-0.25mm; the diameter of the pole is in the range of 1.15mm-2.05mm.

[0023] According to some embodiments of this application, the battery cell assembly further includes a cover film, which is disposed axially on the end of the positive electrode facing away from the cover plate, and radially located between the current collector and the diaphragm.

[0024] According to some embodiments of this application, the end of the manifold facing the cover plate extends beyond the cover membrane.

[0025] According to some embodiments of this application, the end of the manifold facing the cover plate is the first end, and the end away from the cover plate is the second end. At least the second end is located in the mounting hole and in contact with the positive electrode. The protruding part of the pole facing the cover plate is defined as the connecting section. The connecting section is electrically connected to the manifold through a lead wire. In the axial direction, the length of the first welding area where the connecting section is welded to the lead wire is L1, and the axial length of the pole is L2, wherein the value of L1 / L2 ranges from 1 / 6 to 1 / 2.

[0026] According to some embodiments of this application, the value range of L1 / L2 is 1 / 3 to 1 / 2.

[0027] According to some embodiments of this application, the axial length of the connecting segment is L3, and the axial length of the pole is L2, wherein the value of L3 / L2 ranges from 1 / 2 to 5 / 6.

[0028] According to some embodiments of this application, the value range of L3 / L2 is 1 / 2 to 3 / 4.

[0029] According to some embodiments of this application, the ratio of the axial length dimension L2 of the electrode post to the height L4 of the cell assembly ranges from 1 / 6 to 3 / 8.

[0030] According to some embodiments of this application, in the axial direction, the distance between the end face of the negative electrode facing the cover plate and the open end face of the housing is L5, and the distance between the end face of the positive electrode facing the cover plate and the open end face of the housing is L6, where L5 / L6 = 3 / 5 - 1.

[0031] According to some embodiments of this application, the axial height of the housing is 45mm-65mm.

[0032] According to some embodiments of this application, the ratio of the axial dimension of the positive electrode to the axial dimension of the negative electrode is in the range of 3 / 5-1.

[0033] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0034] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a cross-sectional view of a cylindrical battery according to some embodiments of this application. Figure 1 ; Figure 2 This is a cross-sectional view of a cylindrical battery according to some embodiments of this application. Figure 2 ; Figure 3 This is a comparative schematic diagram based on Embodiment 2-1 and Comparative Example 2-2 of this application; Figure 4 This is a comparative schematic diagram based on Embodiment 2-1 and Comparative Example 2-3 of this application; Figure 5 This is a comparative schematic diagram based on Embodiment 5-1 and Comparative Example 5-2 of this application; Figure 6 This is a schematic diagram of the manifold according to an embodiment of this application; Figure 7 This is a comparative schematic diagram based on Embodiment 1-1 and Comparative Examples 1-2 of this application; Figure 8 This is a comparative schematic diagram based on Embodiment 1-1 and Comparative Examples 1-3 of this application.

[0035] Figure label: 100 cylindrical batteries; 1. Housing; 101. Receiving cavity; 11. Open end. 2. Cover plate; 21. Pole post; 211. Connecting section; 22. Lead wire; 23. Plate body; 231. Injection hole; 232. Boss; 233. Pole post hole; 24. Connecting flange; Cell assembly 3; positive electrode 31; mounting hole 311; separator 32; negative electrode 33; cover membrane 34; membrane body 341; extension section 342; 4. Current collector cylinder; 401. First rib 41; 42. Second rib 42; First end 431; Second end 432; First flange 441; Second flange 442; Current collector body 443; Insulating sheet 5. Detailed Implementation

[0036] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0037] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0038] In the description of this utility model, "first feature" and "second feature" may include one or more of the features.

[0039] In the description of this utility model, "multiple" means two or more.

[0040] In the description of this utility model, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or it may include the first and second features not being in direct contact but being in contact through another feature between them.

[0041] In the description of this utility model, the terms "above", "over" and "on top" for the first feature and the second feature include the first feature being directly above or diagonally above the second feature, or simply indicate that the first feature is at a higher horizontal level than the second feature.

[0042] The following is for reference. Figures 1-8 A cylindrical battery 100 according to an embodiment of this application is described.

[0043] A cylindrical battery 100 according to an embodiment of this application includes: a casing 1, a cover plate 2, a cell assembly 3, and a current collector 4. The cylindrical battery 100 has axial, radial, and circumferential directions.

[0044] The housing 1 has an open end 11 on one axial direction. The cover plate 2 is located at the open end 11 of the housing 1. The cover plate 2 and the housing 1 cooperate to define the receiving cavity 101. The cover plate 2 is provided with a pole post 21, and at least part of the pole post 21 is placed in the receiving cavity 101.

[0045] Furthermore, combined Figure 1 and Figure 2 As shown, the battery cell assembly 3 includes a positive electrode 31, a negative electrode 33, and a diaphragm 32 disposed between the positive electrode 31 and the negative electrode 33. The positive electrode 31 has an axially extending mounting hole 311, and the negative electrode 33 is arranged around the outside of the positive electrode 31 and attached to the inner wall of the housing 1.

[0046] The end of the current collector 4 facing the cover plate 2 is the first end 431, and the end of the current collector 4 away from the cover plate 2 is the second end 432. At least the second end 432 or at least part of the current collector 4 is disposed in the mounting hole 311 and in contact with the positive electrode 31. The first end 431 of the current collector 4 is electrically connected to the pole post 21 so as to realize the electrical connection between the positive electrode 31 and the pole post 21 through the current collector 4.

[0047] For example, the current collector can be set in the middle of the cell assembly 3. It should be noted that "the middle of the cell assembly 3" refers to the geometric center area on the cross-section of the cell assembly 3. For example, when the cell assembly 3 is constructed as a hollow cylinder, the middle of the cell assembly 3 is the area near the central axis of the cell assembly 3. The mounting hole 311 can be set through in the axial direction, that is, the mounting hole 311 can be a through hole.

[0048] Reference Figure 1 As shown, specifically, the cover plate 2 includes a plate body 23 and a boss 232. The plate body 23 is provided with an axially penetrating pole hole 233. The boss 232 surrounds the outer periphery of the pole hole 233, and the pole 21 is inserted and engaged with the pole hole 233.

[0049] The “first sidewall” refers to the surface of the main body 23 facing the cell assembly 3, and the boss 232 protrudes from the first sidewall toward the cell assembly 3 relative to the main body 23.

[0050] like Figure 1 and Figure 2As shown, since the plate body 23 has a boss 232 protruding towards the cell assembly 3 on the side facing the cavity 101, a certain gap is formed between the boss 232 and the inner peripheral wall of the shell 1 in the circumferential direction. The gap can be used as an air chamber to buffer the internal pressure and ensure the reliability and stability of the cylindrical battery 100 during the discharge process.

[0051] Furthermore, the cylindrical battery 100 has an insulating sheet 5 inside the receiving cavity 101. The insulating sheet 5 is attached to the surface of the boss 232 facing the cell assembly 3, and the insulating sheet 5 is spaced apart from the plate body 23 so as to form insulation protection on the side of the boss 232 opposite to the cell assembly 3, thereby preventing the cell assembly 3 from contacting the cover plate 2 and causing a short circuit.

[0052] Meanwhile, a filling space can be formed at the boss 232, and glass can be filled in the filling space to form a sealing ring at the mating area between the boss 232 and the pole post 21.

[0053] In some embodiments of this application, the thickness ratio H1 / H2 between the thickness H1 of the boss 232 and the thickness H2 of the plate body 23 in the axial direction ranges from 0.25 to 0.90.

[0054] Understandably, the boss 232 can be used to improve the structural strength of the cover plate 2 in the middle region and improve the connection reliability between the pole post 21 and the cover plate 2. Moreover, while the insulating sheet 5 can be arranged by the boss 232, a buffer space can be formed between the boss 232 and the inner peripheral wall of the housing 1 to serve as a gas chamber to buffer the internal pressure of the cylindrical battery 100.

[0055] In the axial direction, when the thickness ratio H1 / H2 between the thickness H1 of the boss 232 and the thickness H2 of the plate body 23 is in the range of 0.25-0.90, if H1 / H2 is closer to 0.90, the cover plate 2 can provide sufficient glass sealing space, and the thicker boss 232 makes the cavity for accommodating glass powder in the cover plate 2 deeper, thus allowing for sufficient glass powder to be filled. During high-temperature sintering, the molten glass can form a full insulating seal, effectively wrapping the electrode post 21, forming excellent airtightness and insulation. The thicker glass layer can act as a buffer between the electrode post 21 (which has a different coefficient of thermal expansion than glass) and the cover plate 2, reducing thermal stress caused by temperature changes and improving thermal shock resistance and long-term reliability. If H1 / H2 is closer to 0.25, the plate body 23 (H2) is relatively thicker, making the entire cover plate 2 less prone to bending or deformation when subjected to the internal pressure, external extrusion, and encapsulation stress of the cylindrical battery 100, resulting in good mechanical integrity. Therefore, keeping the H1 / H2 range within the range of 0.25-0.90 can achieve a good balance between ensuring the sintering quality of the glass insulator and maintaining the overall mechanical strength of the cover plate 2.

[0056] It should be noted that when the thickness ratio H1 / H2 between the thickness H1 of the boss 232 and the thickness H2 of the main body 23 is less than 0.25 (meaning the boss 232 is too thin), the glass filling space is insufficient, making it difficult to form an effective sealing ring. This results in a high risk of glass insulator sintering failure and unstable airtightness of the sintered cap, making the cylindrical battery 100 prone to slow leakage. Simultaneously, the thin glass layer is easily broken down by the electric field or develops microcracks under mechanical stress, leading to insulation failure and short circuits. Furthermore, the thin glass layer cannot effectively absorb thermal stress and is prone to interface cracking during temperature cycling, resulting in poor sealing and reliability of the cylindrical battery 100.

[0057] Furthermore, when the thickness ratio H1 / H2 between the thickness H1 of the boss 232 and the thickness H2 of the main body 23 is greater than 0.9 (indicating that the thickness of the boss 232 is too thick), the excessive thickness of the boss 232 compared to the main body 23 means that the thickness of the main body 23 is relatively too thin. This results in insufficient mechanical strength of the cover plate 2, making it prone to warping or bulging during the packaging process of the cylindrical battery 100 or under internal gas pressure, affecting the flatness of the cover plate 2. An uneven cover plate 2 will result in poor sealing when it is rolled and packaged with the shell 1. At the same time, an excessively thick boss 232 will also make the stamping process of the cover plate 2 difficult. If a high and steep boss 232 is formed by stamping in one go, the requirements for the ductility of the sheet metal and the mold design are high, and microcracks are easily generated at the root of the boss 232 (i.e., the area where the boss 232 connects to the main body 23), becoming stress concentration points and potential leakage paths. As a result, the cylindrical battery 100 may fail due to mechanical abuse or long-term use.

[0058] In a preferred embodiment of this application, the thickness ratio H1 / H2 ranges from 0.5 to 0.6, thereby further optimizing the thickness ratio between the boss 232 and the plate body 23 to better maintain the overall mechanical strength of the cover plate 2.

[0059] In some embodiments of this application, the thickness H1 of the boss 232 in the axial direction ranges from 0.4mm to 0.9mm, and the thickness H2 of the plate body 23 ranges from 1.0mm to 1.6mm. Therefore, controlling the thickness ratio of the boss 232 to the plate body 23 within a reasonable range helps to improve the overall mechanical strength of the cover plate 2.

[0060] The thickness of the boss 232 can be 0.5mm, 0.6mm, or 0.7mm, etc., and correspondingly, the thickness of the plate body 23 can be 1.0mm, 1.2mm, or 1.4mm, etc. Preferably, the thickness ratio of the boss 232 to the plate body 23 is maintained within the above-mentioned range (i.e., 0.25-0.90).

[0061] Example 4-1 In a specific embodiment 4-1 of this application, the thickness H1 of the boss of the cover plate 2 in the cylindrical battery 100 is 0.65mm, the thickness of the plate body 23 is 1.2mm, and the thickness ratio H1 / H2 between the thickness H1 of the boss 232 and the thickness H2 of the plate body 23 is 0.54.

[0062] At this point, the sintering process of this embodiment performs excellently. The 0.65mm boss height provides ample space for the glass powder, allowing the molten glass to wet the contacting electrode post 21 and cover plate 2, forming a thick, dense, non-porous insulating sealing ring with excellent airtightness, insulation, and thermal shock resistance. The cover plate 2 in this embodiment has sufficient mechanical strength; the 1.0mm thickness of the plate body 23 ensures the overall rigidity and strength of the cover plate 23, effectively resisting the internal pressure and external stress of the cylindrical battery 100, preventing deformation, and keeping stamping processing costs controllable. Furthermore, the requirements for stamping and sintering processes for the cover plate 2 in this embodiment are within a more reasonable range, facilitating stable mass production, resulting in a high overall yield and easier cost control.

[0063] Comparative Example 4-2 In Comparative Example 4-2, the thickness H1 of the boss in the cover plate 2 of the cylindrical battery 100 is 0.18 mm, the thickness of the plate body 23 is 1.2 mm, and the thickness ratio H1 / H2 between the thickness H1 of the boss 232 and the thickness H2 of the plate body 23 is 0.15. This ratio is significantly smaller than the above-mentioned range (i.e., 0.25-0.90).

[0064] At this point, the sintering of Comparative Example 4-2 has sealing defects. The glass insulator is too thin, resulting in poor sealing performance and making the sintering process more difficult to control. The defect rate is high (over 60%), the sintering area is small, and any slight fluctuation in glass powder or temperature can lead to sealing failure, resulting in low production yield. Furthermore, the cylindrical battery 100 prepared by the cover plate 2 in Comparative Example 4-2 is prone to chronic leakage after long-term storage or temperature cycling. The electrolyte vapor inside the cylindrical battery 100 rises along the electrode post 21, causing a decrease in insulation resistance and capacity loss. Moreover, the dielectric strength of the thin glass layer is insufficient, posing a risk of electrical breakdown under high-current pulses or external overvoltage impacts, leading to an internal short circuit in the cylindrical battery 100.

[0065] Comparative Example 4-3 In Comparative Example 4-3, the thickness H1 of the boss in the cover plate 2 of the cylindrical battery 100 is 1.14 mm, the thickness of the plate body 23 is 1.2 mm, and the thickness ratio H1 / H2 between the thickness H1 of the boss 232 and the thickness H2 of the plate body 23 is 0.95, which is significantly larger than the above range (i.e., 0.25-0.90).

[0066] At this point, the rigidity of the cover plate 2 in Comparative Example 4-3 is insufficient. Due to the relatively small thickness of the main body 23, the rigidity of the entire cover plate 2 depends entirely on its 1.2mm thickness. When the internal pressure of the cylindrical battery 100 increases, the cover plate 2 is prone to bulging outward in the central area (i.e., around the electrode post 21), thereby damaging the seal between the cover plate 2 and the casing 1. Simultaneously, the cover plate 2 is difficult to stamp. If a boss 232 of the same height as the main body 23 is to be stamped, the material tension of the cover plate 2 is high, and the stress concentration at the root region of the boss 232 is severe, thinning the metallographic structure and potentially forming invisible microcracks. These microcracks may develop into through-cracks during the battery's lifespan, becoming potential leakage points and posing a safety hazard.

[0067] In some embodiments of this application, the manifold 4 is provided with flow holes 401, and the areal density of the manifold 4 is in the range of 250±50g / m³. 2 It is understandable that the manifold 4 can be unfolded from a cylindrical structure into a sheet-like structure. The unfolded sheet-like structure is called the cylinder wall. The "area density of the manifold" refers to the mass distribution density on its cylinder wall. Simply put, it describes the "mass per unit area of ​​cylinder wall".

[0068] For example, the wall of the manifold 4 can be a metal mesh. The surface density of the metal mesh can reflect its mass per unit area, and can comprehensively reflect the thickness and density of the mesh material. Among them, the density of the mesh material is mainly affected by the width of the strand and the size of the mesh.

[0069] When the surface density of the collector 4 is within the above range (i.e., 250±50g / m³), 2 When the manifold 4 is in operation, its mechanical and electrochemical properties can reach a balance. The metal mesh within this range possesses sufficient rigidity and strength, resulting in excellent mechanical stability of the current collector 4. This ensures the structural integrity of the cylindrical battery 100 during assembly and prevents deformation of the current collector 4. Simultaneously, it provides sufficient support at the current collector 4 to ensure firm attachment of the carbon pack.

[0070] Understandably, if the areal density is too low (e.g., less than 200 g / m³), 2 There may be insufficient metal material, such as too narrow a wire width or too thin a mesh. If the areal density (less than 200 g / m²) is met... 2 The metal mesh processing to form the current collector 4 can provide more filling space for the positive electrode 31 and increase the loading of active material in the positive electrode 31, but it can also easily cause the current collector 4 to bend or crush during the pressing and assembly process, which will lead to a sharp increase in the risk of internal short circuit of the cylindrical battery 100.

[0071] It should be further noted that excessively narrow metal studs cannot provide sufficient support and grip for the carbon pack constituting the positive electrode 31. Therefore, when the cylindrical battery 100 is subjected to vibration or impact, the carbon pack may loosen, leading to increased internal resistance or internal short circuits. Simultaneously, the small cross-sectional area of ​​the material narrows the electron conduction path, potentially resulting in excessively high local current density, which is detrimental to high-current discharge and affects the discharge performance of the cylindrical battery 100.

[0072] If the surface density of the collector 4 is too high (e.g., greater than 300 g / m³), 2 The metal mesh constituting the collector 4 has an excessively wide stem width, excessively small mesh size, or excessive thickness. Under the same pitch, the larger the stem width, the smaller the opening area of ​​the flow passage 401. That is, as the stem width increases, the opening area of ​​the flow passage 401 will decrease, resulting in an increase in the internal resistance (especially the ion resistance) of the cylindrical battery 100.

[0073] It should be further noted that in the cylindrical battery 100, the space occupied by the positive electrode 31 and the current collector 4 is fixed. While a thicker wall of the current collector 4 provides stronger support, it also reduces the filling space of the positive electrode 31, thereby reducing the amount of active material loaded in the positive electrode 31 and consequently lowering the volumetric capacity of the cylindrical battery 100. Furthermore, excessively thick and rigid metal mesh is more difficult to handle during winding into the current collector 4 and welding processes, requiring more sophisticated processing equipment and being prone to poor contact due to significant springback.

[0074] It is evident that the surface density of the manifold 4 has a significant impact on its mechanical and electrochemical properties.

[0075] In a further embodiment of this application, the areal density of the manifold 4 can be in the range of 250±30 g / m³. 2 Therefore, a good balance between the mechanical and electrochemical properties of the manifold 4 can be achieved.

[0076] Example 1-1 In a specific embodiment of this application, the relevant parameters of the manifold 4 are: it uses stretched nickel mesh with an areal density of 245 g / m³. 2 The thickness is 0.2 mm, the stalk width is about 0.28 mm, the short pitch is about 1.1 mm, and the long pitch is about 2.2 mm.

[0077] Cylindrical battery 100 assembly: The current collector 4 in Example 1-1 above is used to assemble a standard ER26500 lithium-ion battery.

[0078] In the above-described embodiment 1-1, the current collector 4 of the cylindrical battery 100 exhibits a complete structure during assembly, without deformation, crushing, or other abnormalities. The carbon pack is firmly attached without any loosening. Furthermore, in performance testing, the initial internal resistance of the cylindrical battery 100 is 3.8Ω, which is excellent. Regarding the capacity of the cylindrical battery 100, when discharged to 2.0V with a standard discharge current, the discharge capacity can reach 8.2Ah, demonstrating high utilization of active materials. Based on the discharge curve, the cylindrical battery 100 exhibits a high and stable voltage platform, indicating good discharge capacity utilization.

[0079] Comparative Examples 1-2 In one of the comparative examples 1-2 of this application, the relevant parameters of the manifold 4 are as follows: it uses a stretched nickel mesh with a surface density of 200 g / m². 2 The thickness is 0.13mm and the width of the strand is about 0.22mm. At this point, the mesh is relatively thin and soft.

[0080] Cylindrical battery 100 assembly: The current collector 4 in Comparative Examples 1-2 above is used to assemble a standard ER26500 lithium-ion battery (same as in Example 1-1).

[0081] In Comparative Examples 1-2 above, during the assembly of cylindrical battery 100, some current collectors showed visible slight deformation during the core pressing process, posing a potential short-circuit risk. Meanwhile, in performance testing, the initial internal resistance of cylindrical battery 100 was 3.8Ω, comparable to Example 1-1. Regarding the capacity of cylindrical battery 100, when discharged to 2.0V with a standard discharge current, the initial discharge capacity was normal, but a voltage drop occurred at the end, and the plateau voltage of the curve was unstable.

[0082] Comparative Examples 1-3 In one of the comparative examples 1-3 of this application, the relevant parameters of the manifold 4 are as follows: it uses a stretched nickel mesh with an areal density of 390 g / m³. 2 The thickness is 0.23 mm and the width of the strand is about 0.45 mm. At this time, the mesh formed by stretching the nickel mesh is dense.

[0083] Cylindrical battery 100 assembly: The current collector 4 in Comparative Examples 1-3 above is used to assemble a standard ER26500 lithium-ion battery (same as in Examples 1-1).

[0084] In the comparative examples 1-3 above, during the assembly of the cylindrical battery 100, the fabrication, shaping, and welding of the current collector 4 had a high defect rate, but the current collector 4 had high strength. Meanwhile, in performance testing, the initial internal resistance of the cylindrical battery 100 was 8.5Ω, indicating severe ohmic polarization; regarding the capacity of the cylindrical battery 100, the standard discharge capacity was only 7.4 Ah, showing significant capacity loss due to the waste of internal active material caused by the low porosity.

[0085] Combination Figure 7 and Figure 8 Based on the above embodiments 1-1, comparative examples 1-2, and comparative examples 1-3, it is known that if the areal density of the current collector 4 is too high or too low, the cylindrical battery 100 will suffer from problems such as deformation of the current collector 4 leading to short circuit risk, unstable voltage output, excessive internal resistance, and low standard discharge capacity. It should be noted that in embodiments 1-1, comparative examples 1-2, and comparative examples 1-3, the short pitch and long pitch parameters are the same or nearly the same, and the specific dimensions will vary due to the influence of the areal density of the current collector 4.

[0086] In some embodiments of this application, the manifold 4 is provided with a plurality of flow holes 401, and the opening ratio of the manifold is 26%-48%.

[0087] When the opening ratio of the current collector 4 meets the above parameter range, it can ensure the contact area between the electrolyte and the positive electrode 31, thereby improving the contact fit between the positive electrode 31 and the electrolyte. It also helps to ensure the rigidity of the current collector 4, reducing the risk of short circuits inside the cylindrical battery 100 caused by bending or crushing deformation of the current collector 4. Simultaneously, it can prevent the current collector 4 from hindering electrolyte wetting and SO2 gas diffusion, preventing an increase in the internal resistance (especially ionic impedance) of the cylindrical battery 100.

[0088] If the opening ratio on the current collector 4 is too large (e.g., the opening ratio of the current collector 4 reaches 60% or 70%), it will lead to a decrease in the safety of the cylindrical battery 100 and damage to its structural integrity.

[0089] Understandably, during the assembly of the cylindrical battery 100, such as the carbon pack pressing step, the current collector 4 needs to withstand a certain amount of mechanical pressure. If the opening ratio of the current collector 4 is too large, it will lead to a decrease in the rigidity of the current collector 4, making it easy to bend or crush, thereby causing the current collector 4 to deform and bulge, piercing the separator 32, and causing an internal short circuit in the cylindrical battery 100. At the same time, if the opening ratio of the current collector 4 is too high, the excessively large mesh structure cannot provide sufficient adhesion, which will cause the carbon pack (i.e., the part that constitutes the positive electrode 31 in the cell assembly 3) to not be tightly attached to the current collector 4. This will make the carbon pack loose relative to the current collector 4 or risk falling off the current collector 4, increasing the internal resistance of the cylindrical battery 100 and affecting the electrical performance at the end of the discharge period to a certain extent, resulting in a certain loss of the total amount of electricity that the cylindrical battery 100 can release.

[0090] Furthermore, if the opening ratio on the current collector 4 is too small (e.g., the opening ratio of the current collector 4 is only 10% or 15%), the electrolyte will not be able to fully contact the positive electrode 31, which will increase the internal resistance of the cylindrical battery 100.

[0091] Understandably, the core function of the current collector 4 is to collect current. The aforementioned "inability of the electrolyte to fully contact the positive electrode 31" refers to the following: if the opening size or number of openings on the current collector 4 is too small, it will restrict the diffusion and migration channels of lithium ions in the electrolyte within the positive electrode 31, leading to a sharp increase in ionic impedance and thus increasing the internal resistance of the cylindrical battery 100. Simultaneously, the difficulty in ion migration will prevent the effective utilization of the active material in the positive electrode 31, resulting in a lower actual discharge capacity of the battery and affecting the discharge performance of the cylindrical battery 100.

[0092] According to the embodiments of this application, the cylindrical battery 100, by maintaining the opening ratio on the current collector 4 within the above-mentioned range, can ensure the contact and fit effect between the positive electrode 31 and the electrolyte, thereby ensuring the discharge capacity of the cylindrical battery 100, and also helps to ensure the rigidity of the current collector 4, reducing the risk of short circuit inside the cylindrical battery 100 caused by bending or crushing deformation of the current collector 4.

[0093] Combination Figure 1 and Figure 2 As shown, the collector 4 may include a plurality of spaced first ribs 41 and a plurality of spaced second ribs 42. Each first rib 41 intersects with a plurality of second ribs 42, and each second rib 42 intersects with a plurality of first ribs 41, so that the plurality of interlocking first ribs 41 and the plurality of second ribs 42 together define a plurality of flow holes 401, and the flow holes 401 located in the mounting hole 311 are directly opposite to the positive electrode 31.

[0094] Furthermore, since each first rib 41 intersects and engages with multiple second ribs 42, and each second rib 42 intersects and engages with multiple first ribs 41, the flow passage 401 is formed by the joint enclosure of the first ribs 41 and the second ribs 42. Each flow passage 401 can be formed by one first rib 41 and multiple second ribs 42, or by one second rib 42 and multiple first ribs 41, or by multiple first ribs 41 and multiple second ribs 42.

[0095] Understandably, at the cell assembly 3, a mounting hole 311 is formed by enclosing the positive electrode 31. The mounting hole 311 is used to arrange the aforementioned current collector 4 and can also be used to contain the electrolyte in the cylindrical battery 100. Simultaneously, a flow-through hole 401 is formed on the current collector 4, allowing the electrolyte to pass through and contact the wall surface enclosing the mounting hole 311, ensuring effective contact between the electrolyte and the positive electrode 31. Under the adsorption effect of the positive electrode 31, the electrolyte is transferred to the negative electrode 33, ensuring that all electrodes inside the cylindrical battery 100 can contact the electrolyte and undergo a chemical reaction. This allows the cylindrical battery 100 to maintain the same discharge capacity regardless of its orientation (e.g., horizontal, vertical, or tilted in the application environment), thus improving the applicability of the cylindrical battery 100.

[0096] Reference Figure 1 As shown, when the first end 431 of the collector tube 4 extends out of the positive electrode 31, the first end 431 is located outside the mounting hole 311, so that the collector tube 4 can be electrically connected to the pole post 21 through the part of the collector tube 4 located outside the mounting hole 311.

[0097] Specifically, in this example, the portion of the manifold 4 located within the mounting hole 311 has multiple flow holes 401 to allow the electrolyte to diffuse to the positive electrode 31 through the flow holes 401. Alternatively, the portion of the manifold 4 located outside the mounting hole 311 may also have multiple flow holes 401, eliminating the need to control the positional relationship between the flow holes 401 and the positive electrode 31 during manufacturing; the portion of the manifold 4 located outside the mounting hole 311 may also be without flow holes to ensure the structural strength of this portion and facilitate welding.

[0098] It is understandable that the flow passage 401 on the axial manifold 4 corresponding to the positive electrode 31 plays the main flow passage role, that is, the flow passage 401 located in the mounting hole 311 plays the main flow passage role. Therefore, the opening ratio of the manifold 4 in this application specifically refers to the opening ratio of the part of the manifold 4 located in the mounting hole 311.

[0099] In a further embodiment of this application, the opening ratio of the current collector 4 is 32%-42%, thereby controlling the opening ratio of the current collector 4 within a better range, which helps the electrolyte to contact the positive electrode 31, ensuring the discharge capacity of the cylindrical battery 100, and making the current collector 4 have high rigidity, effectively preventing the current collector 4 from bending or crushing during assembly, and improving the safety and reliability of the cylindrical battery 100.

[0100] Example 2-1 Reference Figure 6As shown, in a specific embodiment of this application, the relevant parameters of the manifold 4 are as follows: it uses stretched nickel mesh, the width of the strand is 0.3 mm (the width dimension at the intersection of the first rib 41 and the second rib 42), the short pitch is 1.1 mm, the long pitch is 2.2 mm, and the calculated and measured opening rate is 40%; Meanwhile, the performance test results of the cylindrical battery 100 are as follows: Internal resistance: The initial internal resistance is 4.5Ω, which is at an excellent level; Capacity: When discharged from 20mA to 2.0V, the release capacity reaches 8.1Ah, with high utilization rate of active material; Mechanical properties: The current collector 4 showed no deformation or crushing during the pressing of the positive electrode 31 carbon pack, and the carbon pack adhered firmly.

[0101] Comparative Example 2-2 In Comparative Example 2-2, the relevant parameters of the manifold 4 are as follows: the manifold parameters are drawn nickel mesh, the wire width is 0.04 mm, the short pitch is 1.5 mm, the long pitch is 2.2 mm (that is, the long pitch dimension in Comparative Example 2-2 is the same as the long pitch dimension in Example 2-1), and its opening ratio is 49%; Meanwhile, the performance test results of cylindrical battery 100 in Comparative Example 2-2 are as follows: Internal resistance: The initial internal resistance is low, at 1.0Ω; Capacity: When discharged to 2.0V with a current of 20mA, the initial capacity is normal and can reach 7.8Ah, with a high capacity utilization rate, but there is abnormal voltage fluctuation at the end of the discharge. Mechanical properties: The current collector is relatively soft, and some parts underwent slight deformation during the pressing of the positive electrode 31 carbon pack, which poses a potential risk.

[0102] Comparative Examples 2-3 In Comparative Examples 2-3, the relevant parameters of the manifold 4 are as follows: the manifold parameters are drawn nickel mesh, the wire width is 0.8 mm, the short pitch is 1.0 mm, the long pitch is 2.2 mm (that is, the long pitch dimension in Comparative Example 2-3 is the same as the long pitch dimension in Example 2-1), and its opening ratio is 25%; Meanwhile, the performance test results of cylindrical battery 100 in Comparative Examples 2-3 are as follows: Internal resistance: The initial internal resistance is as high as 9.8Ω; Capacity: When discharged to 2.0V with a current of 20mA, the capacity is only 7.0Ah, the capacity loss is serious, and the discharge plateau voltage fluctuation is greater than ±50mV.

[0103] In this case, the battery assembly method of Example 2-1 is the same as that of Comparative Examples 2-2 and 2-3, such as: all are assembled into ER26500 lithium thionyl chloride batteries.

[0104] Combination Figure 1 and Figure 2 As shown, in some embodiments of this application, each flow hole 401 is formed as a quadrilateral.

[0105] As described above, the flow passage 401 can be formed by the first rib 41 and the second rib 42. When the flow passage 401 is formed by four ribs (e.g., two first ribs 41 and two second ribs 42), the flow passage 401 is a quadrilateral hole, which can be a rhomboid hole, a rectangular hole, etc.

[0106] In a specific embodiment of this application, multiple first ribs 41 in the collector tube 4 are arranged in parallel pairs, and multiple second ribs 42 are also arranged in parallel pairs, so that a quadrilateral hole can be formed by two adjacent first ribs 41 and two adjacent second ribs 42, specifically, a rhombus can be formed.

[0107] It should be noted that the opening ratio = mesh area / area of ​​one grid unit × 100%. When the flow holes 401 in the collector cylinder 4 are arranged in a rhombus shape, the opening ratio = ((short pitch - stem width / 2) × (long pitch - stem width / 2) / 2) / (short pitch × long pitch) × 100%.

[0108] Furthermore, among the plurality of first ribs 41, the spacing between any two adjacent first ribs 41 is the same, that is, the plurality of first ribs 41 are arranged at equal intervals; similarly, among the plurality of second ribs 42, the spacing between any two adjacent second ribs 42 is the same, that is, the plurality of second ribs 42 are arranged at equal intervals. Thus, the plurality of first ribs 41 and second ribs 42 can enclose and form a plurality of flow holes 401 with the same shape and opening area, allowing the flow holes 401 to be evenly distributed on the collector cylinder 4, thereby facilitating the contact and engagement of the electrolyte with the positive electrode 31.

[0109] Understandably, during the forming process of the manifold 4, multiple straight-line extending first ribs 41 can be arranged in parallel and at equal intervals, and multiple straight-line extending second ribs 42 can be arranged in parallel and at equal intervals. Each first rib 41 can be overlapped with multiple second ribs 42. The multiple first ribs 41 and multiple second ribs 42 arranged in a roughly coplanar manner are then enclosed to form a cylindrical structure that matches the shape of the mounting hole 311. The enclosed ends are then welded together to form a hollow cylindrical manifold 4.

[0110] It should be noted that the cylinder wall of the manifold 4 is constructed of stretched mesh (also known as expanded mesh or stretched mesh plate). The stretched mesh is made using a highly efficient metal processing technology, the core principle of which is "cutting-stretching". That is, a solid piece of metal is processed into a mesh through plastic deformation. The "cutting" mentioned above refers to removing gaps in the sheet metal and forming a hole structure through stretching. After the stretched mesh is enclosed, a manifold 4 with diamond-shaped flow holes 401 can be formed.

[0111] In some embodiments of this application, the thickness of the first rib 41 and the thickness of the second rib 42 are the same, so that the current collector 4 can be constructed with an overall wall thickness of approximately the same, so as to improve the conductivity between different areas in the current collector 4, avoid the problem of excessive local resistance in the current collector 4, and help improve the overall discharge effect of the cylindrical battery 100.

[0112] like Figure 2 As shown, in some embodiments of this application, the collector 4 can be constructed as a tapered structure with a tapered bottom (i.e., away from the cover plate 2), and the upper part of the collector 4 is constructed as a cylindrical structure with a uniform cross-section.

[0113] Combination Figure 1 and Figure 2 As shown, in some embodiments of this application, the first end 431 of the current collector 4 extends beyond the mounting hole 311 towards the cover plate 2 to prevent the positive electrode 31 from expanding above the current collector 4. It should be noted that if the positive electrode 31 extending above the current collector 4 has an excessively long internal electron transport path, it will affect the discharge performance of the cylindrical battery 100.

[0114] It should be noted that the collector 4 can be electrically connected to the pole 21 at the cover plate 2 via the lead wire 22. By setting the collector 4 to protrude the mounting hole 311 to one side of the cover plate 2, the distance between the collector 4 and the cover plate 2 can be shortened, making it easier to electrically connect the cover plate 2 and the collector 4 via the lead wire 22.

[0115] During the assembly of the current collector 4 and the battery cell assembly 3, the current collector 4 is pressed into the housing 1 by the carbon pack (i.e. the positive electrode 31 part in the battery cell assembly 3) and located on the circumferential outer side of the current collector 4, and the current collector 4 is placed in the mounting hole 311 formed by the carbon pack, so that the current collector 4 can support the wall surface that defines the mounting hole 311.

[0116] It is understandable that the collector 4 is constructed as a hollow cylindrical structure. The collector 4 has a first end 431 and a second end 432 at its two ends in the axial direction. The first end 431 is the end of the collector 4 that is close to the cover plate 2, and the second end 432 is the end of the collector 4 that is away from the cover plate 2.

[0117] In some embodiments of this application, the first end 431 is provided to extend out of the mounting hole 311, that is, the first end 431 extends out of the positive electrode 31 on one side of the cover plate 2 in the axial direction of the cylindrical battery 100.

[0118] In this application, by placing the first end 431 of the current collector 4 outside the mounting hole 311 formed by the positive electrode 31, it is possible to prevent the positive electrode 31 from expanding and protruding above the current collector 4. Furthermore, the electrode post 21 can be electrically connected to the part of the current collector 4 placed outside the mounting hole 311 through the lead wire 22, thereby reducing the difficulty of electrically connecting the lead wire 22 to the current collector 4.

[0119] In some embodiments of this application, at least one end of the manifold 4 is provided with a reinforcing portion.

[0120] In some embodiments of this application, the first end 431 of the manifold 4 is provided with a first reinforcing part (i.e. the reinforcing part mentioned above). The first reinforcing part is electrically connected to the pole post 21 through the lead wire 22 to improve the deformation resistance of the manifold 4 at the first end 431 and avoid welding deformation of the manifold 4.

[0121] In some embodiments of this application, a second reinforcing part (i.e., the aforementioned reinforcing part) is provided at the second end of the collector cylinder 4 away from the cover plate 2, so as to improve the structural strength of the collector cylinder 4 at the bottom (i.e. the end of the collector cylinder 4 away from the cover plate 2) through the second reinforcing part, which helps to improve the deformation resistance of the collector cylinder 4 at the bottom.

[0122] Reference Figure 1 As shown, in a further embodiment of this application, the first reinforcing part is a multi-layer structure, so as to further improve the deformation resistance of the first end 431 through the multi-layer structure and avoid welding deformation of the manifold 4.

[0123] Furthermore, the first reinforcing part has a double-layer structure, which is formed by the inward folding of the flow collector 4.

[0124] Specifically, the first end 431 is provided with a first flange 441 that bends toward the inside of the collector cylinder 4, the first reinforcing part includes the first flange 441, and the first flange 441 is electrically connected to the pole post 21 through the lead wire 22 for ease of manufacturing.

[0125] It is understandable that the collector 4 has a first flange 441 at the first end 431. The first flange 441 bends toward the hollow area of ​​the collector 4 to improve the structural strength of the collector 4 at the first end 431, thereby enhancing the deformation resistance of the collector 4 at the first end 431. This allows the collector 4 to provide reliable circumferential support for the positive electrode 31 at the first end 431. Furthermore, the setting of the first flange 441 facilitates the positioning of the connection position between the first end 431 and the lead wire 22, reducing the difficulty of electrical connection between the lead wire 22 and the collector 4.

[0126] The collector cylinder 4 also includes a collector body 443, which is cylindrical in shape. A first flange 441 is bent inward from the upper end of the collector body 443 and fits snugly against the inner circumferential wall of the collector body 443. This forms a double-layer structure at the first end 431 of the collector cylinder 4 through the cooperation of the first flange 441 and the collector body 443. This improves the structural strength of the collector cylinder 4 at the first end 431, enhances its resistance to deformation at the first end 431, and provides a reliable connection structure for the electrical connection between the lead wire 22 and the pole post 21.

[0127] Reference Figure 1 As shown, in some embodiments of this application, the second reinforcing part is a multi-layer structure, so as to further improve the deformation resistance at the second end 432 through the multi-layer structure and avoid welding deformation of the manifold 4.

[0128] Furthermore, the second reinforcing part has a double-layer structure, which is formed by the inward folding of the flow collector 4.

[0129] Specifically, in the axial direction of the cylindrical battery 100, the second end 432 of the current collector 4 away from the cover plate 2 is provided with a second flange 442 that bends toward the inside of the current collector 4. The second reinforcing part includes the second flange, so as to improve the structural strength of the current collector 4 at the second end 432 through the second flange 442, thereby improving the deformation resistance of the current collector 4 at the second end 432, so that the current collector 4 can provide reliable circumferential support for the positive electrode 31 at the second end 432.

[0130] Furthermore, the second flange 442 is bent inward from the lower end of the current collecting body 443, and the second flange 442 fits snugly against the inner circumferential wall of the current collecting body 443, so that the first flange 441 and the current collecting body 443 cooperate to form a double-layer structure at the first end 431 of the current collecting cylinder 4, thereby improving the structural strength of the current collecting cylinder 4 at the second end 432 and enhancing the deformation resistance of the current collecting cylinder 4 at the second end 432, so as to provide reliable circumferential support for the bottom of the positive electrode 31 through the second end 432.

[0131] In some embodiments of this application, the lengths of the first reinforcing part and the second reinforcing part are the same in the axial direction of the cylindrical battery 100, so that the collector 4 can have high structural strength at both ends in the axial direction, so as to ensure the structural strength of the collector 4 at the first end 431 and the second end 432, and also reduce the assembly difficulty of the collector 4 in the housing 1.

[0132] It is understandable that when the lengths of the first and second reinforcing parts are the same, the cylindrical manifold 4 has a symmetrical structure. During the assembly of the manifold 4, it is necessary to arrange the manifold 4 in the housing 1, without considering whether the manifold 4 is upside down in the housing 1.

[0133] Reference Figure 1 As shown, in some other embodiments of this application, the length of the first reinforcing part is greater than the length of the second reinforcing part, which makes the strength of the current collector 4 at the first end 431 higher, which helps to improve the circumferential support effect of the current collector 4 on the inner peripheral wall of the positive electrode 31.

[0134] Understandably, during the assembly of the cylindrical battery 100, the positive electrode 31 in the cell assembly 3 is typically press-fitted onto the circumferential outer side of the current collector 4. In this application, because the first reinforcing portion of the current collector 4 at its first end 431 is longer, the current collector 4 has better resistance to deformation at its first end 431, ensuring the assembly reliability of the cylindrical battery 100. This helps reduce the risk of deformation or crushing of the current collector 4 during the assembly of the cell assembly 3, allowing the positive electrode 31 (such as a carbon pack) to fit tightly with the current collector 4, reliably attaching and fixing the positive electrode 31 to the current collector 4. This reduces the interfacial contact resistance between the positive electrode 31 and the current collector 4, providing a stable path for the rapid and efficient transfer of electrons between them.

[0135] In a further embodiment of this application, the length of the portion of the manifold 4 used to connect with the lead wire 22 is a first connection length, and the length of the first flange 441 is greater than the first connection length.

[0136] It is understood that the first flange 441 is used to enhance the structural strength of the manifold 4 at the first end 431, and the connection and mating position between the lead wire 22 and the manifold 4 is located at the end of the manifold 4 where the first flange 441 is provided. In this application, by setting the length of the first flange 441 to be greater than the first connection length, the structural strength of the area in the manifold 4 used for electrical connection and mating with the lead wire 22 can be enhanced, thereby improving the connection reliability between the lead wire 22 and the manifold 4 and reducing the risk of desoldering.

[0137] In some embodiments of this application, the wall of the manifold 4 is a mesh structure (e.g., nickel mesh), and the flow holes 401 are mesh holes, so that the mesh structure can be used to form a hollow cylindrical structure and constitute the manifold 4, which simplifies the forming method of the manifold 4.

[0138] In a further embodiment of this application, the lead wire 22 is a nickel strip, and the cylinder wall of the manifold 4 is a nickel mesh.

[0139] Specifically, the nickel mesh can be one of soft nickel mesh, semi-hard nickel mesh or hard nickel mesh, with semi-hard nickel mesh being preferred, in order to improve the overall strength performance of the manifold 4 during processing and after forming.

[0140] It is understandable that nickel mesh and nickel strip have excellent conductivity, which can effectively conduct current, thereby improving the energy conversion efficiency of cylindrical battery 100 during discharge. In addition, nickel mesh has a certain structural strength, which can provide mechanical support for positive electrode 31 and help improve the strength of the inner peripheral wall of positive electrode 31 that surrounds the mounting hole 311.

[0141] Meanwhile, the nickel mesh can form a dense oxide film on its surface in a strongly alkaline environment, which improves the oxidation resistance of the current collector 4 and helps reduce the risk of short circuits inside the cylindrical battery 100. In addition, the nickel mesh has good corrosion resistance and high temperature resistance, which can meet the requirements for use in high temperature environments and help improve the discharge efficiency of the cylindrical battery 100.

[0142] In some embodiments of this application, the distance between the end face of the first end 431 and the adjacent end face of the positive electrode 31 is D1, and the distance between the end face of the first end 431 and the end face of the open end 11 is D2, with D1 / D2 = 0.32-0.68. That is, the ratio of D1 to D2 is in the range of 0.32-0.68, for example: 0.4, 0.5, 0.6, etc.

[0143] In a further embodiment of this application, D1 / D2 = 0.45-0.60, such as 0.5, 0.55, etc.

[0144] Specifically, the first end 431 of the current collector 4 is higher than the positive electrode 31. When the ratio of the height of the end of the current collector 4 extending from the positive electrode 31 to the height distance between the current collector 4 and the open end 11 of the housing 1 is within the range of 0.32-0.68, it ensures that the current collector 4 can provide a sufficiently large area for low-resistance, reliable welding, thereby achieving the low internal resistance and full design capacity of the cylindrical battery 100. At the same time, sufficient and necessary safety insulation distance can be reserved between the current collector 4 and the cover plate 2 to effectively reduce the short-circuit risk of the cylindrical battery 100 during the manufacturing process.

[0145] Understandably, within the above value range, there is no need to excessively sacrifice the space of the active material in the cylindrical battery 100 in order to optimize the capacity. Furthermore, a reasonable value range can ensure that the cylindrical battery 100 is easier to implement and control during the manufacturing process, thus guaranteeing production stability and a high yield.

[0146] It should be noted that when the above ratio is too small (less than 0.32), the portion of the current collector 4 extending beyond the positive electrode 31 is short, or the distance between the current collector 4 and the open end 11 of the casing 1 is too large. When the portion of the current collector 4 extending beyond the positive electrode 31 is too small, the operating space for welding (e.g., laser welding) or mechanical pressing at the current collector 4 is severely limited, leading to problems such as weak welding and incomplete welds. This reduces the reliability and mechanical strength of the welded connection area, posing a short-circuit risk to the cylindrical battery 100 in a vibration environment. When the distance between the current collector 4 and the open end 11 of the casing 1 is too large, the overall height of the positive electrode 31 decreases, reducing the loading of positive electrode active material in the cylindrical battery 100, resulting in a decrease in the rated capacity and low volumetric energy density of the cylindrical battery 100.

[0147] Furthermore, when the aforementioned ratio is too large (greater than 0.68), the portion of the current collector 4 extending beyond the positive electrode 31 is too long, or the distance between the current collector 4 and the open end face 11 of the housing 1 is too small. Since the positive electrode 31, negative electrode 33, and cover plate 2 are separated only by a single insulating layer, if the height of the current collector 4 is very close to the plane of the housing 1 at the open end 11, any slight misalignment during the pressing of the cover plate 2 into the cylindrical battery 100 could cause the end of the current collector 4 to pierce or squeeze the insulating layer, leading to a short circuit in the cylindrical battery 100 or an increased risk of short circuits. This results in high precision requirements for the mechanical assembly of the cylindrical battery 100, leading to decreased equipment yield and a significant increase in manufacturing costs.

[0148] Example 3-1 In a specific embodiment of this application, the ratio of the height of the end of the collector 4 extending from the positive electrode 31 to the height distance of the collector 4 from the open end 11 of the housing 1 is 0.55, the height of the collector 4 from the open end 11 of the housing 1 is 7.6 mm, and the height of the end of the collector 4 extending from the positive electrode 31 is 4.2 mm.

[0149] At this point, the height of the end of the current collector 4 extending beyond the positive electrode 31 provides ample operating space for laser welding, ensuring welding reliability and enabling the cylindrical battery 100 to have low connection internal resistance and superior vibration resistance. Simultaneously, a 7.6mm space is reserved between the current collector 4 and the open end 11 of the housing 1, providing a safe insulation distance, effectively mitigating assembly tolerances, reducing short-circuit risks, and ensuring the volumetric energy density of the cylindrical battery 100 without sacrificing the height of the positive electrode 31. Therefore, the parameters of this embodiment place reasonable demands on the machining accuracy of components and assembly processes, facilitating high yield rates in mass production.

[0150] Comparative Example 3-2 In Comparative Example 3-2, the ratio of the height of the end of the collector 4 extending from the positive electrode 31 to the height of the collector 4 from the open end 11 of the housing 1 is 0.28 (exceeding the lower limit of the range), the height of the collector 4 from the open end 11 of the housing 1 is 7.6 mm, and the height of the end of the collector 4 extending from the positive electrode 31 is 2.1 mm.

[0151] At this point, the height of the end of the current collector 4 extending beyond the positive electrode 31 is only 2.1 mm, resulting in a limited welding area formed above the positive electrode 31. This necessitates precise energy input during laser welding; otherwise, insufficient penetration may lead to incomplete welding, or excessive energy may burn through the current collector 4, directly increasing the process difficulty and manufacturing cost. Simultaneously, the limited connection area may cause a slight increase in contact resistance and current collector resistance, resulting in a voltage drop exceeding the maximum allowable DC internal resistance during high-pulse discharge.

[0152] Comparative Example 3-3 In Comparative Example 3-3, the ratio of the height of the end of the collector 4 extending from the positive electrode 31 to the height of the collector 4 from the open end 11 of the housing 1 is 0.684 (slightly higher than the upper limit of the range), the height of the collector 4 from the open end 11 of the housing 1 is 7.6 mm, and the height of the end of the collector 4 extending from the positive electrode 31 is 5.2 mm.

[0153] At this point, the requirements for the thickness, strength, and alignment during assembly become stringent in Comparative Example 3-3. Any minor defect in the insulation or misalignment of the cover plate 2 during pressing may lead to insufficient gap between the positive electrode 31 and the negative electrode 33, resulting in a significantly higher risk of short-circuit failure compared to the previous two examples (Example 3-1 and Comparative Example 3-2). This necessitates the use of more precise molds, more uniform insulating materials, and more stable assembly equipment to maintain yield in the cylindrical battery 100, thereby increasing production costs.

[0154] In a further embodiment of this application, the axial height of the current collector 4 is 35mm-55mm, such as 40mm, 50mm, etc.; the axial height of the housing 1 is 45mm-65mm, such as 50mm, 60mm, etc.; and the circumferential height of the positive electrode 31 is 30mm-50mm, such as 35mm, 40mm, etc. Therefore, the dimensions of the current collector 4 and the housing 1 in the axial direction of the cylindrical battery 100 can be designed within the above ranges to control the ratio of the height of the end of the current collector 4 extending from the positive electrode 31 to the height distance between the current collector 4 and the end face of the open end 11 of the housing 1 within a reasonable range.

[0155] In some embodiments of this application, the end of the negative electrode 33 facing the cover plate 2 extends beyond the positive electrode 31 in the axial direction of the cylindrical battery 100. (Refer to...) Figure 1As shown, the end of the negative electrode 33 away from the cover plate 2 is flush with the end of the positive electrode 31 away from the cover plate 2. By setting the end of the negative electrode 33 beyond the positive electrode 31 on one side of the cover plate 2, it helps to prevent the positive electrode 31 from expanding and rising above the negative electrode 33, so as to ensure the discharge effect of the cylindrical battery 100.

[0156] like Figure 1 As shown, the outer diameter of the current collector 4 remains unchanged along the axial direction of the cylindrical battery 100, making the overall structure of the current collector 4 regular and facilitating the installation and cooperation of the cell assembly 3 and the current collector 4 in the receiving cavity 101.

[0157] Reference Figure 1 As shown, the current collector 4 can penetrate the positive electrode 31, and the second end 432 of the current collector 4 is located at the bottom of the positive electrode 31. This helps to reduce the electron path, reduce internal resistance, and improve the discharge performance of the cylindrical battery 100. Furthermore, the current collector 4, which has a uniform cross-section in the axial direction, can provide good support for the cell assembly 3, thus helping to improve the reliability of the cylindrical battery 100 structure. At the same time, the uniform cross-section of the current collector 4 also facilitates the arrangement of the cell assembly 3 on its circumferential outer side by press fitting, allowing the cell assembly 3 to be filled between the current collector 4 and the inner circumferential wall of the housing 1.

[0158] like Figure 1 and Figure 2 As shown, in some embodiments of this application, in the axial direction of the cylindrical battery 100, the separator 32 extends beyond the positive electrode 31 and the negative electrode 33 toward the end of the cover plate 2, so that the separator 32 can separate the positive electrode 31 and the negative electrode 33.

[0159] Reference Figure 1 As shown, the battery cell assembly 3 includes a positive electrode 31, a separator 32, and a negative electrode 33. The separator 32 is located circumferentially outside the positive electrode 31 and circumferentially inside the negative electrode 33. That is, the separator 32 is disposed between the positive electrode 31 and the negative electrode 33 to prevent direct contact between the positive electrode 31 and the negative electrode 33, thus avoiding a short circuit in the cylindrical battery 100. In this application, the separator 32 is protruding towards the cover plate 2, so that the separator 32 can effectively separate the positive electrode 31 and the negative electrode 33.

[0160] It should be noted that the separator 32 is constructed as a microporous structure that allows ions (such as lithium ions) to pass through, and it also insulates and isolates the positive electrode 31 and the negative electrode 33 to ensure the reliability of the battery during charging and discharging. Furthermore, the separator 32 provides mechanical support for the positive electrode 31 and the negative electrode 33, which helps in the formation of the cell assembly 3. Simultaneously, the separator 32 can withstand the volume changes and pressure of the cylindrical battery 100 during discharge, thereby improving the reliability of the cylindrical battery 100. The separator 32 can be made of materials such as PE (polyethylene) and PP (polypropylene); no specific material is limited to the separator 32 here.

[0161] Combination Figure 1 and Figure 2 As shown, in a further embodiment of this application, there is a gap between the end of the diaphragm 32 facing the cover plate 2 and the cover plate 2, thereby preventing interference between the diaphragm 32 and the cover plate 2 and ensuring the assembly reliability of the cylindrical battery 100.

[0162] It is understandable that the battery cover 2 needs to be installed and fixed after the cell assembly 3 is assembled. If the length of the separator 32 protruding too much from the positive electrode 31 and the negative electrode 33 on one side of the cover 2, the separator 32 may be deformed by the cover 2, which may cause the separator 32 to interfere with components such as the terminal post 21 and the lead wire 22. In this application, the end of the separator 32 adjacent to the cover 2 is spaced apart from the cover 2 in the axial direction of the cylindrical battery 100, so that the separator 32 can effectively separate the positive electrode 31 and the negative electrode 33 while reducing the risk of interference between the separator 32 and other components (such as the lead wire 22 and the cover 2) in the receiving cavity 101.

[0163] Reference Figure 1 As shown, when a portion of the current collector 4 protrudes from the positive electrode 31, this portion of the current collector 4 is located outside the mounting hole 311, allowing the current collector 4 to be electrically connected to the electrode post 21 through the portion of the current collector 4 located outside the mounting hole 311, thus facilitating the electrical connection between the current collector 4 and the electrode post 21.

[0164] In some embodiments of this application, the cover plate 2 further includes a connecting flange 24, which is disposed at the outer periphery of the plate body 23 and bends and extends away from the receiving cavity 101. The connecting flange 24 is fixedly connected to the shell 1, thereby improving the structural strength of the cover plate 2 at the outer periphery through the connecting flange 24, thereby improving the deformation resistance of the cover plate 2 in the circumferential direction, so that the cover plate 2 can provide good support for the shell 1 in the circumferential direction, which helps to improve the strength of the cylindrical battery 100 at one end of the cover plate 2.

[0165] In some embodiments, the connecting flange 24 protrudes from the side away from the receiving cavity 101; in other embodiments, the connecting flange 24 protrudes from the side towards the receiving cavity 101; in still other embodiments, part of the connecting flange 24 protrudes from the side away from the receiving cavity 101, and another part of the connecting flange 24 protrudes from the side towards the receiving cavity 101.

[0166] The connecting flange 24 can be folded to one side of the axial direction to increase the flange area, or it can be bent to one side of the axial direction first and then folded to the other side of the axial direction to reduce the protrusion height of the connecting flange 24 on both sides of the cover plate 2 while ensuring the flange area.

[0167] In a further embodiment of this application, in the axial direction, the maximum height of any surface of the protruding plate body connecting the flange 24 is the protrusion height H3, the thickness of the plate body 23 is H2, and the ratio range between the protrusion height H3 and the thickness H2 is 0.05-1, such as 0.1, 0.5, etc.

[0168] It is understandable that if the protrusion height of the connecting flange 24 is smaller than that of the main body 23, it will not play a role in strengthening the fixation; if the protrusion height of the connecting flange 24 is larger than that of the main body 23, the area occupied by the cover plate 2 in the receiving cavity 101 will be larger, which will reduce the volume on the side where the battery cell assembly 3 is placed and reduce the discharge capacity.

[0169] In some preferred embodiments of this application, the ratio H3 / H2 between the protrusion height H3 and the thickness H2 is in the range of 0.1-0.5, such as 0.2, 0.3, etc., so as to further control the protrusion height of the connecting flange 24 at the plate body 23 and the thickness of the plate body 23 within a reasonable range.

[0170] In some embodiments of this application, the protrusion height H3 ranges from 0.05mm to 0.2mm, and the height of the housing 1 ranges from 45mm to 65mm. The thickness of the cover plate 2 in the area where the connecting flange 24 is located ranges from 0.4mm to 1.0mm.

[0171] In some embodiments of this application, the cover plate 2 further includes a connecting flange 24, which is disposed at the outer periphery of the plate body 23 and bends and extends away from the receiving cavity 101. The connecting flange 24 is fixedly connected to the shell 1, thereby improving the structural strength of the cover plate 2 at the outer periphery through the connecting flange 24, thereby improving the deformation resistance of the cover plate 2 in the circumferential direction, so that the cover plate 2 can provide good support for the shell 1 in the circumferential direction, which helps to improve the strength of the cylindrical battery 100 at one end of the cover plate 2.

[0172] In a further embodiment of this application, the axial height of the connecting flange 24 is H3, the thickness of the plate body 23 is H2, and the ratio of the convex height H3 to the thickness H2 is in the range of 0.05-0.2.

[0173] It is understandable that if the protrusion height of the connecting flange 24 is smaller than that of the main body 23, it will not play a role in strengthening the fixation; if the protrusion height of the connecting flange 24 is larger than that of the main body 23, the area occupied by the cover plate 2 in the receiving cavity 101 will be larger, which will reduce the volume on the side where the battery cell assembly 3 is placed and reduce the discharge capacity.

[0174] In some preferred embodiments of this application, the ratio H3 / H2 between the protrusion height H3 and the thickness H2 is in the range of 0.1-0.15, so as to further control the protrusion height of the connecting flange 24 at the plate body 23 and the thickness of the plate body 23 within a reasonable range.

[0175] In some embodiments of this application, the protrusion height H3 ranges from 0.05mm to 0.2mm, and the height of the housing 1 ranges from 45mm to 65mm. The thickness of the cover plate 2 in the area where the connecting flange 24 is located ranges from 0.4mm to 1.0mm.

[0176] In some embodiments of this application, in the axial direction of the cylindrical battery 100, the end of the connecting flange 24 (i.e. the end away from the receiving cavity 101) is flush with the open end 11 of the housing 1, thereby facilitating the installation and positioning between the cover plate 2 and the housing 1 by the engagement of the connecting flange 24 with the end face of the open end 11 of the housing 1.

[0177] In some other embodiments of this application, at least part of the connecting flange 24 protrudes from the side surface of the main body 23 away from the receiving cavity 101, and in the axial direction of the cylindrical battery 100, the end of the connecting flange 24 (i.e. the end away from the receiving cavity 101) is lower than the open end 11 of the housing 1, so as to ensure the reliability of the connection between the cover plate 2 and the housing 1, and avoid the problem that the cover plate 2 will fall off the housing 1 due to the lateral impact force caused by the connecting flange 24 protruding from the housing 1.

[0178] It is understandable that the cover plate 2 can be installed and fixed to the housing 1 by press fitting, so that the cover plate 2 and the housing 1 have an interference fit, thereby realizing the connection and fixation between the cover plate 2 and the housing 1. During the press fitting assembly process of the cover plate 2, the connecting flange 24 can be kept flush with or lower than the open end 11 of the housing 1, so that the peripheral wall of the housing 1 can shield the cover plate 2 in the circumferential direction, avoiding the cover plate 2 from being directly subjected to lateral impact force and deforming and falling off, which helps to improve the consistency and reliability of the cylindrical battery 100.

[0179] like Figure 1 As shown, in some embodiments of this application, the plate body 23 is provided with a liquid injection hole 231, which is provided through the thickness direction (which is also the axial direction of the cylindrical battery 100) so that the electrolyte can be injected into the receiving cavity 101 through the liquid injection hole 231.

[0180] Furthermore, the electrolyte injection hole 231 is positioned opposite the positive electrode 31 in the axial direction of the cylindrical battery 100 to ensure the effective injection of electrolyte into the receiving cavity 101 through the electrolyte injection hole 231. It is understood that after the electrolyte injection operation is completed through the electrolyte injection hole 231, the injection hole 231 can be sealed to ensure the airtightness of the receiving cavity 101.

[0181] like Figure 1 and Figure 2 As shown, in some embodiments of this application, the battery cell assembly 3 further includes a cover film 34, which covers the end of the positive electrode 31 opposite to the cover plate 2 and is located between the outer circumferential side of the current collector 4 and the inner circumferential side of the separator 32, so as to constrain and position the positive electrode 31 by the cover film 34, constrain and limit the carbon pack at one end in the axial direction, and ensure the forming effect of the battery cell at the positive electrode 31.

[0182] In a further embodiment of this application, the cover film 34 includes a film body 341 and an extension 342. The film body 341 is disposed opposite to and attached to the positive electrode 31 in the axial direction. The extension 342 is connected to the outer periphery of the film body 341 and extends in the axial direction away from the positive electrode 31.

[0183] Furthermore, the extension section 342 fits into the inner peripheral wall of the diaphragm 32, and the cover membrane 34 can be connected and fixed to the diaphragm 32 through the extension section 342, thereby fixing the position of the cover membrane 34 relative to the cell and improving the fit between the cover membrane 34 and the positive electrode 31.

[0184] In some embodiments of this application, the lead wire 22 is provided with a bend to facilitate the electrical connection and cooperation between the collector 4 and the pole post 21 via the lead wire 22.

[0185] Reference Figure 1 As shown, the lead wire 22 is used to electrically connect the current collector 4 and the terminal 21. In the axial direction of the cylindrical battery 100, the terminal 21 and the current collector 4 are staggered. By forming a bend in the lead wire 22, the lead wire 22 can correspond to and connect with both the current collector 4 and the terminal 21 at the same time, so that the electrical connection between the current collector 4 and the terminal 21 can be achieved through the lead wire 22.

[0186] In some embodiments of this application, the lead wire 22 is a nickel wire. The nickel wire has low resistivity, which can ensure the electrical connection effect between the current collector 4 and the electrode 21. In addition, the nickel wire facilitates the routing of the lead wire 22 between the current collector 4 and the electrode 21, which can reduce the difficulty of the electrical connection operation between the current collector 4 and the electrode 21.

[0187] In the axial direction of the cylindrical battery 100, the protruding part of the pole post 21 towards the cover plate 2 is defined as the connecting section 211. The connecting section 211 is electrically connected to the current collector 4 through the lead wire. The length of the first welding area where the connecting section 211 and the lead wire 22 are welded together is L1. The axial length of the pole post 21 is L2, and the value of L1 / L2 is in the range of 1 / 6 to 1 / 2.

[0188] Reference Figure 1 As shown, the current collector 4 is constructed as a cylindrical structure and is located on the circumferential inner side of the battery cell assembly 3 (i.e., inside the mounting hole 311). The mounting hole 311 is filled with electrolyte (not shown), and the electrolyte can directly contact the positive electrode 31 through the flow hole 401 of the current collector 4.

[0189] It is understandable that the electrode 21 is electrically connected to the current collector 4 through the lead wire 22. When the connecting section 211 extends into the current collector 4, the electrode 21 can be correspondingly matched with part of the current collector 4 in the axial direction of the cylindrical battery 100, thereby shortening the distance between the connecting section 211 and the current collector 4, so as to facilitate the electrical connection between the connecting section 211 and the current collector 4 through the lead wire 22.

[0190] Furthermore, the length of the first welding area in the connecting section 211 that is welded to the lead wire 22 is L1, and the axial length of the pole post 21 is L2, and L1 / L2 is within the range of 1 / 6-1 / 2, so as to ensure the connection fit length between the connecting section 211 and the lead wire 22 and improve the electrical connection fit effect between the lead wire 22 and the pole post 21.

[0191] It is understandable that by keeping the connection length between the connecting section 211 and the lead wire 22 within a suitable range, the connection area between the connecting section 211 and the lead wire 22 can be guaranteed, which helps to reduce the resistance between the current collector 4 and the pole 21.

[0192] Furthermore, when the ratio of the length of the first welding area between the connecting segment 211 and the lead wire 22 to the terminal post 21 meets the aforementioned range, the electrical connection between the terminal post 21 and the lead wire 22 can be guaranteed. This also ensures that the length of the terminal post 21 within the receiving cavity 101 is kept within a suitable range, preventing the connection segment 211 from being too long and affecting the flow of the electrolyte. Conversely, if the connecting segment 211 is too long, it will occupy more space, reducing the electrolyte content within the mounting hole 311 and negatively impacting the discharge efficiency of the cylindrical battery 100.

[0193] It should be noted that if the length of the first welding area formed between the connecting segment 211 and the lead wire 22 is too short (i.e., less than 1 / 6 of the axial length of the terminal post 21), the mechanical connection strength between the connecting segment 211 and the lead wire 22 will be insufficient, the welding area will be small, making the connection point fragile and prone to incomplete welding. Consequently, when the cylindrical battery 100 is subjected to vibration or accidental impact, the weld point (i.e., the connection point) may crack, leading to an internal open circuit and complete failure of the cylindrical battery 100. At the same time, the contact resistance between the lead wire 22 and the terminal post 21 will be high, and the narrow point of the current path will generate significant Joule heat. Especially during pulse discharge, this part (i.e., the aforementioned narrow point) will experience localized overheating, which will not only waste energy but also accelerate the aging of the cylindrical battery 100 and even lead to the risk of thermal runaway. Furthermore, it will result in high process difficulty and poor reliability. In other words, an excessively short welding area requires high equipment precision and process stability, and is prone to quality problems such as incomplete welding and false welding, leading to a decrease in the yield of the cylindrical battery 100.

[0194] If the length of the first welding area formed between the connecting section 211 and the lead wire 22 is too large (e.g., exceeding 1 / 2 of the axial length of the terminal post 21), it will lead to the risk of deformation of the upper part of the current collector 4, affecting the sealing of the cylindrical battery 100 at the cover plate 2 and the insulation of other components, increasing the risk of internal short circuit. At the same time, welding beyond the necessary length will not significantly improve the connection performance, but will instead increase welding time and energy consumption, reduce production efficiency, and the excessively large heat-affected zone may change the mechanical properties of the current collector 4, making the current collector 4 brittle.

[0195] According to the cylindrical battery 100 of this application embodiment, the length L1 of the first welding area formed between the connecting section 211 and the lead wire 22 is designed to correspond to the axial length L2 of the electrode post 21. This facilitates the correspondence between the connecting section 211 and the lead wire 22 led out from the current collector 4 and ensures the electrical connection effect between the connecting section and the lead wire 22. It also avoids the electrode post 21 being too long, which would have an adverse effect on the flow of electrolyte, thereby improving the discharge effect of the cylindrical battery 100.

[0196] Specifically, by designing the length of the connecting section 211, it is possible to ensure that the terminal post 21 has a certain mechanical strength and that there is sufficient welding area at the connecting section 211, so that the terminal post 21 and the current collector 4 can withstand the vibration, impact and stress that may occur during the assembly of the cylindrical battery 100 and during long-term use. At the same time, it can also provide sufficient operating space for processes such as welding (e.g., laser welding) between the lead wire 22 and the terminal post 21, and between the lead wire 22 and the current collector 4, and ensure the quality and consistency of the weld points.

[0197] In a further embodiment of this application, the value range of L1 / L2 is 1 / 3-1 / 2, thereby better improving the connection and cooperation effect between the terminal 21 and the lead wire 22, which helps to reduce the internal resistance of the cylindrical battery 100.

[0198] In some embodiments of this application, the axial length of the connecting segment 211 is L3, and the axial length of the pole 21 is L2, wherein the value of L3 / L2 ranges from 1 / 2 to 5 / 6.

[0199] In a further preferred embodiment of this application, 1 / 2-3 / 4 is used to control the length of the connecting segment 211 within a suitable proportional range, thereby ensuring the electrical connection effect between the connecting segment 211 and the collector cylinder 4.

[0200] In some embodiments of this application, the ratio of the axial length L2 of the electrode post 21 to the axial height L4 of the cell assembly 3 ranges from 1 / 6 to 3 / 8. This allows the length of the electrode post 21 extending into the hollow structure of the current collector 4 to be kept within a suitable range, ensuring a balance between assembly and welding performance of the cylindrical battery 100.

[0201] It is understandable that if the length of the terminal 21 extending into the current collector 4 is too long, it will affect the assembly of the cylindrical battery 100. During the assembly process of the cylindrical battery 100, when pressing the cover plate 2 into the housing 1, an excessively long terminal 21 and current collector 4 will result in excessive assembly resistance, which may cause mechanical interference between the bottom of the current collector 4 and the bottom insulating film, scratching or squeezing the bottom insulating film, thus leading to defects in the cylindrical battery 100. The excessive length of the terminal 21 will also cause positioning difficulties during assembly, especially on high-speed assembly lines. The terminal 21 and current collector 4 may misalign, leading to a decrease in the yield of the cylindrical battery 100, increasing rework costs and scrap rate. Herein, the assembly resistance is the resistance generated by the deformation of the terminal 21 or current collector 4.

[0202] Furthermore, if the length of the terminal post 21 extending into the current collector 4 is too short, fundamental operational difficulties and performance defects will arise. The connection and fixation between the terminal post 21 and the lead wire 22, as well as between the current collector 4 and the lead wire 22, are typically achieved through welding (such as laser welding). This results in insufficient effective overlap area and weld depth on the terminal post 21, leading to a small weld volume and shallow weld depth. Consequently, when the cylindrical battery 100 is subjected to vibration or impact, the weld joint is prone to splitting or detachment, causing an internal short circuit in the cylindrical battery 100. Incomplete weld joints also introduce significant contact resistance. Simultaneously, if the terminal post 21 is too short, energy control during welding is difficult, easily resulting in incomplete fusion and weak welds. A cylindrical battery 100 with weak welds may conduct initially, but its resistance is high and unstable. Over time or with temperature changes, the weak weld joints may oxidize, overheat, or even fail completely, causing intermittent operation or sudden damage to the cylindrical battery 100. Moreover, this defect is difficult to detect 100% during factory inspection.

[0203] In some embodiments of this application, the distance between the end face of the negative electrode 33 facing the cover plate 2 and the open end face of the housing 1 in the axial direction is L5, and the distance between the end face of the positive electrode 21 facing the cover plate 2 and the open end face of the housing 1 is L6, where L5 / L6=3 / 5-1. This can prevent the positive electrode 31 from expanding and becoming higher than the negative electrode 33, which helps to improve material utilization and the overall performance of the cylindrical battery 100.

[0204] It should be noted that in the design of the cylindrical battery 100 (e.g., lithium-ion battery), after the cover plate 2 and the casing 1 of the cylindrical battery 100 are assembled, the reserved height between the upper surface of the negative electrode 33 and the cover plate 2 is not greater than the reserved height between the upper surface of the positive electrode 31 and the cover plate 2. This ensures that after the positive electrode 31 (e.g., carbon pack) absorbs the electrolyte, during the discharge process, the consumption surface of the negative electrode 33 is always within the 'projection' range of the reaction zone of the positive electrode 31, so as to improve the utilization rate of reactants and help improve the utilization rate of materials and the overall performance of the battery.

[0205] The carbon pack constituting the positive electrode 31 has a porous structure and a low density before the electrolyte is injected. After the electrolyte (such as thionyl chloride electrolyte) is injected, the carbon pack expands axially. In order to ensure that the consumption surface of the negative electrode 33 is always completely covered by the reaction area of ​​the positive electrode 31 during the discharge process of the cylindrical battery 100, the above-mentioned expansion needs to be compensated.

[0206] In this application, by constructing the axial height of the negative electrode 33 to be greater than the axial height of the positive electrode 31, after the cylindrical battery 100 is injected with electrolyte and immersed, the carbon pack expands, and the shipment height of the expanded carbon pack is similar to (e.g., the shipment height of the carbon pack is lower than the height of the negative electrode 33) or equal to that of the negative electrode 33, thereby achieving spatial matching of the two active materials.

[0207] It should be emphasized that after the cylindrical battery 100 is discharged, the positive electrode 31 will expand further. Therefore, the negative electrode 33 in the cylindrical battery 100 that has not participated in the discharge operation can be constructed to have a height slightly higher than the shipping height of the expanded carbon pack.

[0208] Understandably, if the above parameter range is not met, the carbon pack portion above the negative electrode 33 in the cylindrical battery 100 will not participate in the reaction during discharge, resulting in a decrease in the capacity of the cylindrical battery 100 and a waste of positive electrode material. Furthermore, the excess carbon pack portion that cannot participate in the reaction occupies the internal space of the cylindrical battery 100, causing this space to be ineffectively occupied, resulting in a low volumetric energy density of the cylindrical battery 100, that is, a lower capacity for the same battery volume.

[0209] In some embodiments of this application, the ratio of the axial dimension of the positive electrode 31 to the axial dimension of the negative electrode 33 is in the range of 3 / 5-1. It should be noted that the "positive electrode 31" mentioned above refers to the initial height of the positive electrode portion composed of carbon packs, that is, the state when the carbon packs are not immersed in electrolyte.

[0210] Example 5-1 In a specific embodiment 5-1 of this application, in the cylindrical battery 100 (such as model ER26500), the height of the carbon pack of the positive electrode 31 is 33.3 mm, the height of the negative electrode 33 (such as lithium negative electrode) is 35.0 mm, the height ratio of the negative electrode 33 to the positive electrode 31 is 1.05, which falls within the range of 1-5 / 3, and the estimated liquid absorption expansion rate of the carbon pack is 5%.

[0211] After the cylindrical battery 100 is filled with electrolyte and immersed, the carbon pack expands and the shipment height is about 35.0 mm. At this time, the height of the negative electrode 33 (35.0 mm) is roughly equal to the height of the expanded carbon pack (35.0 mm).

[0212] Therefore, throughout the entire discharge process of the cylindrical battery 100, the reaction zones of the negative electrode 33 and the positive electrode 31 are covered from top to bottom, allowing all the lithium metal constituting the negative electrode 33 to participate in the reaction. The active materials of both the positive electrode 31 and the negative electrode 33 are utilized, and there is no "dead lithium" or "waste of positive electrode material" caused by spatial mismatch. This makes the actual discharge capacity of the cylindrical battery 100 close to the theoretically designed target value, such as a designed capacity of 8500mAh. In this embodiment, the cylindrical battery 100 discharges at room temperature with a current of 20mA to 2.0V, with a capacity of 8.1Ah. It has high energy density, and due to the uniform reaction, the internal resistance of the cylindrical battery 100 is relatively stable throughout the entire discharge cycle, and the output voltage platform is stable.

[0213] Comparative Example 5-2 In Comparative Example 5-2, the battery model is the same as that in the above embodiment (e.g., model ER26500). In the cylindrical battery 100, the height of the carbon pack, which is constructed as the positive electrode, is 33.3 mm, and the height of the negative electrode 33 (e.g., lithium negative electrode) is 32.0 mm. The height ratio is 0.96 (less than 1, not within the above range), and the estimated liquid absorption expansion rate of the carbon pack is 5%.

[0214] After the cylindrical battery 100 is filled with electrolyte and immersed, the carbon pack expands and the shipment height is about 35.0 mm. At this time, the height of the negative electrode 33 (32.0 mm) is significantly smaller than the height of the expanded carbon pack (35.0 mm).

[0215] Therefore, inside the cylindrical battery 100, there is a region of approximately 3 mm in height at the top of the carbon pack that lacks a corresponding negative electrode reaction zone. This results in the positive electrode material (such as thionyl chloride and carbon) in this area rarely participating in effective electrochemical reactions throughout the battery's lifespan. In other words, a portion of the positive electrode active material does not contribute to the capacity after being packed into the casing 1, leading to a significant reduction in the measured capacity of the cylindrical battery 100. Simultaneously, the wasted positive electrode material occupies internal battery space, causing a decrease in the volumetric energy density of the cylindrical battery 100. At the end of the discharge phase, since the effective lithium negative electrode has been consumed, although there is a large amount of unreacted positive electrode material remaining in the cylindrical battery 100, the voltage drops sharply, resulting in permanent waste of positive electrode material and loss of battery capacity.

[0216] Furthermore, under the same discharge mode, the discharge capacity of this comparative example 5-2 is 7.4 Ah.

[0217] Reference Figure 5 As shown, Figure 5 The figure shows a comparison of the discharge curves of the above embodiment and Comparative Example 5-2. The discharge curve of Embodiment 5-1 is significantly better than that of Comparative Example 5-2.

[0218] Combination Figure 3 and Figure 4 A schematic diagram comparing the discharge curves (time-voltage) between a specific embodiment and two comparative examples according to this application.

[0219] It should be noted that in the cylindrical battery 100, by reasonably distributing the thickness of the negative electrode 33 (e.g., lithium negative electrode), separator 32, current collector 4 and positive electrode 31 (e.g., carbon pack) within the casing 1, sufficient thickness space is left for the positive electrode 31 (e.g., carbon pack) to ensure capacity, and necessary small gaps are also reserved for a safe and reliable assembly process. Therefore, the design of the current collector 4 in the cylindrical battery 100 is crucial.

[0220] Under the premise of ensuring smooth assembly, it is possible to achieve contact between the manifold 4 and the carbon bag, and improve the utilization rate of the internal space of the steel shell to increase the capacity.

[0221] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," 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 present invention. In this specification, the 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.

[0222] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A cylindrical battery having axial, radial, and circumferential directions, characterized in that, The cylindrical battery includes: The housing has an open end at one axial position of the cylindrical battery. A cover plate is provided at the open end of the housing. The cover plate and the housing cooperate to define a receiving cavity. The cover plate includes a plate body and a boss. The plate body is provided with an axially penetrating pole hole. The boss surrounds the outer periphery of the pole hole. The electrode post passes through the electrode post hole and extends into the receiving cavity; A battery cell assembly is disposed within the receiving cavity. The battery cell assembly includes a positive electrode, a negative electrode, and a separator. The positive electrode has an axially extending mounting hole. The negative electrode is arranged around the outside of the positive electrode and attached to the inner wall of the housing. The separator is located between the positive electrode and the negative electrode. The current collector, at least a portion of which is disposed within the mounting hole and in contact with the positive electrode, is electrically connected to the electrode post via a connecting wire, and has multiple flow holes.

2. The cylindrical battery according to claim 1, characterized in that, The boss protrudes toward the receiving cavity along the axial direction of the cylindrical battery.

3. The cylindrical battery according to claim 1, characterized in that, Along the axial direction of the cylindrical battery, the thickness ratio H1 / H2 between the thickness H1 of the boss and the thickness H2 of the plate body ranges from 0.25 to 0.

90.

4. The cylindrical battery according to claim 3, characterized in that, The thickness ratio H1 / H2 ranges from 0.5 to 0.

6.

5. The cylindrical battery according to claim 3, characterized in that, Along the axial direction of the cylindrical battery, the thickness H1 of the boss is 0.4mm-0.9mm, and the thickness H2 of the plate body is 1.0mm-1.6mm.

6. The cylindrical battery according to claim 1, characterized in that, The cover plate also includes a connecting flange, which is located at the outer periphery of the plate body and protrudes away from and / or toward the receiving cavity. The connecting flange is fixedly connected to the shell.

7. The cylindrical battery according to claim 6, characterized in that, Along the axial direction of the cylindrical battery, the maximum height of the connecting flange protruding from any surface of the plate body is the protrusion height H3, the thickness of the plate body is H2, and H3 / H2 is 0.05-1.

8. The cylindrical battery according to claim 7, characterized in that, The H3 / H2 ratio is 0.1-0.

5.

9. The cylindrical battery according to claim 7, characterized in that, The protrusion height H3 is 0.05mm-0.2mm.

10. The cylindrical battery according to claim 6, characterized in that, Along the axial direction of the cylindrical battery, the end of the connecting flange away from the receiving cavity is flush with the open end of the housing; or, the end of the connecting flange away from the receiving cavity is lower than the open end of the housing.

11. The cylindrical battery according to any one of claims 1-10, characterized in that, A reinforcing portion is provided at least one end of the current collector along the axial direction of the cylindrical battery.

12. The cylindrical battery according to claim 11, characterized in that, Along the axial direction of the cylindrical battery, the current collector has a first flange at its first end near the cover plate, and the reinforcing part includes the first flange; and / or The second end of the collector cylinder, away from the cover plate, is provided with a second flange, and the reinforcing part includes the second flange.

13. The cylindrical battery according to claim 12, characterized in that, Along the axial direction of the cylindrical battery, the length of the first flange and the length of the second flange are the same; or, The length of the first flange is greater than the length of the second flange.

14. The cylindrical battery according to any one of claims 1-10, characterized in that, The wall of the collector cylinder has a mesh structure, and the flow passage is a mesh.

15. The cylindrical battery according to claim 14, characterized in that, The flow collector includes a plurality of spaced-apart first ribs and a plurality of spaced-apart second ribs, each of the first ribs intersecting with a plurality of the second ribs and each of the second ribs intersecting with a plurality of the first ribs, and each flow hole is defined by the intersecting first ribs and second ribs.

16. The cylindrical battery according to claim 15, characterized in that, The thickness of the first rib is the same as the thickness of the second rib.

17. The cylindrical battery according to claim 14, characterized in that, The thickness of the manifold is in the range of 0.15mm-0.25mm; The diameter of the pole is in the range of 1.15mm-2.05mm.

18. The cylindrical battery according to any one of claims 1-10, characterized in that, The cell assembly also includes a cover film. In the axial direction of the cylindrical battery, the cover film is disposed on the end of the positive electrode facing the cover plate, and in the radial direction, the cover film is located between the current collector and the separator.

19. The cylindrical battery according to claim 18, characterized in that, The end of the manifold facing the cover plate extends beyond the cover membrane.

20. The cylindrical battery according to any one of claims 1-10, characterized in that, The end of the collector facing the cover plate is the first end, and the end away from the cover plate is the second end. At least the second end is located in the mounting hole and is in contact with the positive electrode. The protruding part of the pole facing the cover plate is defined as the connecting section. The connecting section is electrically connected to the collector through a lead wire. Along the axial direction of the cylindrical battery, the length of the first welding area where the connecting section is welded to the lead wire is L1, and the axial length of the electrode post is L2, wherein the value of L1 / L2 ranges from 1 / 6 to 1 / 2.

21. The cylindrical battery according to claim 20, characterized in that, The value range of L1 / L2 is 1 / 3 to 1 / 2.

22. The cylindrical battery according to claim 20, characterized in that, The axial length of the connecting section is L3, and the axial length of the pole is L2, wherein the value of L3 / L2 ranges from 1 / 2 to 5 / 6.

23. The cylindrical battery according to claim 22, characterized in that, The value range of L3 / L2 is 1 / 2 to 3 / 4.

24. The cylindrical battery according to claim 20, characterized in that, The ratio of the axial length L2 of the electrode post to the height L4 of the battery cell assembly ranges from 1 / 6 to 3 / 8.

25. The cylindrical battery according to claim 20, characterized in that, Along the axial direction of the cylindrical battery, the distance between the end face of the negative electrode facing the cover plate and the open end face of the casing is L5, and the distance between the end face of the positive electrode facing the cover plate and the open end face of the casing is L6, where L5 / L6 = 3 / 5 - 1.

26. The cylindrical battery according to claim 25, characterized in that, The axial height of the housing is 45mm-65mm.

27. The cylindrical battery according to claim 20, characterized in that, The ratio of the axial dimension of the positive electrode to the axial dimension of the negative electrode is in the range of 3 / 5-1.

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