Positive electrode insulating sheet for cylindrical battery and cylindrical lithium ion battery
Patent Information
- Application Number
- CN202611253024.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-18
- Publication Date
- 2026-10-27
AI Technical Summary
[0016]本发明公开的圆柱电池用正极绝缘片设置有防偏转定位件，防偏转定位件能提升装配一致性，使装配和搬运时偏转角≤2°，消除偏转导致的正极集流盘边缘覆盖不足与短路风险，短路不良率显著下降，使用体验好。
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Figure CN122992296A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery technology, and more particularly to a positive electrode insulating sheet for cylindrical batteries and a cylindrical lithium-ion battery. Background Technology
[0002] The positive electrode insulator (or upper insulator) is a key insulating structural component inside a cylindrical battery, typically located between the positive current collector and the wound cell. The positive electrode insulator provides electrical isolation, preventing direct contact and short circuits between the current collector and the positive electrode plate of the cell. It also works in conjunction with the cap and sealing ring to achieve a double seal for the electrolyte, absorbing assembly tolerances and cyclic dimensional variations through mechanical buffering.
[0003] Currently, there is one type of insulating sheet, including an edge, with an insulating sheet body fixedly connected to one side of the edge, and a liquid-permeable component provided on one side of the insulating sheet body. The liquid-permeable component includes a connecting post, with an insulating mesh plate fixedly connected to one side of the connecting post, and a liquid-permeable layer provided on one side of the insulating mesh plate. Another type of insulating sheet includes an inner layer, outer layers provided on both sides of the inner layer, and a transition layer provided between the inner and outer layers. The inner layer is a polypropylene alloy, the outer layer is an alloy of polyethylene and polyolefin, and the transition layer is an alloy of polypropylene and polyolefin.
[0004] The defects of the aforementioned insulating sheet include: lack of positioning structure, severe deflection during assembly and handling, sometimes with a deflection angle of 8° to 12°, resulting in some areas not covering the edge of the current collector and a high short-circuit failure rate. Summary of the Invention
[0005] The purpose of this invention is to propose a positive electrode insulating sheet for cylindrical batteries and a cylindrical lithium-ion battery, which solves the problem of large deflection angle of existing insulating sheets and provides a better user experience.
[0006] To achieve this objective, the present invention employs the following technical solution: A positive electrode insulating sheet for a cylindrical battery includes a sheet-shaped sheet body. The sheet body includes a first surface and a second surface disposed opposite to each other. An anti-deflection positioning member is formed on the first surface or the side peripheral surface of the sheet body. The anti-deflection positioning member can make the assembly deflection angle of the positive electrode insulating sheet less than a set value.
[0007] In one preferred embodiment, a central hole is provided in the middle of the sheet body, and the anti-deflection positioning member is at least one annular positioning protrusion, all of which are located on the first surface and concentrically surround the central hole; and / or, the anti-deflection positioning member is at least three positioning ribs, all of which are located on the first surface and extend radially outward along the central hole; and / or, the anti-deflection positioning member is at least twelve teeth, all of which are located on the side circumferential surface of the sheet body and extend radially outward along the central hole.
[0008] In one preferred embodiment, a chamfer is provided on the inner wall surface of the central hole, the chamfer extending radially from the inner wall surface of the central hole toward the center of the central hole.
[0009] In one preferred embodiment, a sealing rib is formed on the second surface and near the outer periphery of the sheet body, the sealing rib protruding from the second surface.
[0010] In one preferred embodiment, in the axial cross-section of the sheet body, the sealing rib is semi-circular, and the straight side of the semi-circular structure is attached to the second surface; or, the sealing rib is trapezoidal, and the long side of the trapezoidal structure is attached to the second surface; or, the sealing rib is triangular, and one side of the triangular structure is attached to the second surface.
[0011] In one preferred embodiment, the sealing rib is arranged in a ring around the center of the sheet body, and the top surface of the sealing rib is parallel to the second surface.
[0012] In one preferred embodiment, the sheet body is made of polyethylene terephthalate, polyethylene naphthalate, polyimide, or polyphenylene sulfide.
[0013] In one preferred embodiment, the surface of the sheet body is coated or screen-printed and then baked to form a ceramic coating. The material used to prepare the ceramic coating includes Al2O3 or SiO2. The breakdown voltage of the ceramic coating is greater than or equal to a set value.
[0014] In one preferred embodiment, at least four electrolyte channel grooves are formed on the second surface, the electrolyte channel grooves extending radially outward from the center of the sheet body.
[0015] On the other hand, the present invention adopts the following technical solution: A cylindrical lithium-ion battery includes a cylindrical casing, a battery cell, a positive current collector, and a cap sealing ring. The battery cell, the positive current collector, and the cap sealing ring are sequentially arranged in the cylindrical casing. The cylindrical lithium-ion battery also includes the aforementioned cylindrical battery positive electrode insulating sheet. The positive electrode insulating sheet is disposed in the cylindrical casing and located between the positive current collector and the cap sealing ring. The outer diameter of the positive current collector is less than the outer diameter of the positive electrode insulating sheet and less than the inner diameter of the cylindrical casing.
[0016] The positive electrode insulating sheet for cylindrical batteries disclosed in this invention is provided with an anti-deflection positioning component. The anti-deflection positioning component can improve assembly consistency, making the deflection angle ≤2° during assembly and transportation, eliminating the risk of insufficient coverage of the positive electrode current collector edge and short circuit caused by deflection, significantly reducing the short circuit failure rate and improving the user experience.
[0017] The cylindrical lithium-ion battery disclosed in this invention includes the above-mentioned positive electrode insulating sheet, which has high assembly consistency, is easy to disassemble and transport, and has a small deflection angle during assembly and handling. After assembly, the positive electrode insulating sheet completely covers the edge of the positive electrode current collector and does not form wrinkles inside the cylindrical shell, which meets the requirements of geometric self-consistency. The positive electrode insulating sheet and the cap sealing ring form a double seal. Attached Figure Description
[0018] Figure 1 This is a cross-sectional view of a cylindrical lithium-ion battery provided in a specific embodiment of the present invention; Figure 2 This is a schematic diagram of an anti-deflection positioning component structure provided in a specific embodiment of the present invention; Figure 3 This is a schematic diagram of another anti-deflection positioning component structure provided in a specific embodiment of the present invention; Figure 4 This is a schematic diagram of another anti-deflection positioning component structure provided in a specific embodiment of the present invention; Figure 5 This is a cross-sectional view of the positive electrode insulating sheet provided in a specific embodiment of the present invention; Figure 6 This is a cross-sectional view of half of the positive electrode insulating sheet provided in a specific embodiment of the present invention; Figure 7 This is a schematic diagram of a sealing rib structure provided in a specific embodiment of the present invention; Figure 8 This is a schematic diagram of another sealing rib structure provided in a specific embodiment of the present invention; Figure 9 This is a schematic diagram of another sealing rib structure provided in a specific embodiment of the present invention; Figure 10 This is a schematic diagram comparing the high-temperature aging of the 14-line seal with the sealing ribs and the flat seal. Figure 11 This is a schematic diagram of an electrolyte flow channel structure provided in a specific embodiment of the present invention; Figure 12 This is a schematic diagram of another electrolyte guide channel structure provided in a specific embodiment of the present invention.
[0019] In the picture: 1. Positive electrode insulating sheet; 2. Cylindrical outer shell; 3. Battery cell; 4. Positive electrode current collector; 5. Cap sealing ring; 11. Sheet body; 12. Center hole; 13. Anti-deflection positioning component; 14. Sealing rib; 15. Chamfer; 16. Ceramic coating; 17. Electrolyte guide groove; 131. Positioning protrusion; 132. Positioning rib; 133. Raised tooth. Detailed Implementation
[0020] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.
[0021] Examples of embodiments of the present invention are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar components or components having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.
[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.
[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0024] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0025] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0026] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.
[0027] This embodiment discloses a positive electrode insulating sheet for a cylindrical battery and a cylindrical lithium-ion battery. The cylindrical lithium-ion battery can be, but is not limited to, a 21650 all-tab cylindrical lithium battery, belonging to the field of battery internal insulation and sealing.
[0028] like Figure 1 As shown, the cylindrical lithium-ion battery includes a positive electrode insulating sheet 1, a cylindrical outer shell 2, a battery cell 3, a positive electrode current collector 4, and a cap sealing ring 5. The battery cell 3, the positive electrode current collector 4, and the cap sealing ring 5 are sequentially arranged inside the cylindrical outer shell 2. The positive electrode insulating sheet 1 is arranged inside the cylindrical outer shell 2 and located between the positive electrode current collector 4 and the cap sealing ring 5. The outer diameter of the positive electrode current collector 4 < the outer diameter of the positive electrode insulating sheet 1 ≤ the inner diameter of the cylindrical outer shell 2. After assembly, the positive electrode insulating sheet 1 completely covers the edge of the positive electrode current collector 4 and does not form wrinkles inside the cylindrical outer shell 2, which meets the requirement of geometric self-consistency. The positive electrode insulating sheet 1 and the cap sealing ring 5 form a double seal.
[0029] like Figure 1 and Figure 5 As shown, the positive electrode insulating sheet 1 includes a sheet body 11 in the shape of a circular thin sheet. The sheet body 11 includes a first surface and a second surface disposed opposite to each other. An anti-deflection positioning member 13 is formed on the first surface or the side peripheral surface of the sheet body 11. The anti-deflection positioning member 13 can make the assembly deflection angle of the positive electrode insulating sheet 1 less than a set value.
[0030] The anti-deflection positioning component 13 improves assembly consistency, ensuring that the deflection angle is ≤2° during assembly and handling. This eliminates the risk of insufficient edge coverage and short circuit caused by deflection of the positive current collector 4, significantly reducing the short circuit failure rate and providing a better user experience.
[0031] The material used to prepare the sheet body 11 is not limited. In this embodiment, the sheet body 11 is made of any one of polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), or polyphenylene sulfide (PPS) film / injection molded part.
[0032] The specific dimensions of the sheet body 11 are not limited. In this embodiment, the outer diameter of the sheet body 11 is 19.0 mm ≤ 20.5 mm; the thickness of the sheet body 11 is 0.15 mm ≤ 0.40 mm, preferably 0.25 mm; the single-piece weight of the sheet body 11 is 0.05 g ≤ 0.20 g; the production yield is ≥ 99.8%; the sheet body 11 possesses excellent mechanical properties (tensile strength ≥ 150 MPa) as well as temperature resistance and electrical insulation (volume resistivity ≥ 10 Ω·cm). 14 Ω·cm).
[0033] Based on the above structure, a central hole 12 is provided in the middle of the main body 11. The function of the central hole 12 is to avoid the central needle or to serve as a liquid injection channel. The specific size of the central hole 12 is not limited. In this embodiment, the diameter of the central hole 12 is 2mm ≤ 5mm, preferably 3.5mm.
[0034] The specific shape of the anti-deflection positioning component 13 is not limited, as long as it can effectively reduce the deflection angle. In one structure, such as... Figure 2 As shown, the anti-deflection positioning element 13 consists of at least one annular positioning protrusion 131, all of which are located on the first surface and concentrically surround the central hole 12. The specific size of the positioning protrusion 131 is not limited; in this embodiment, the height of the positioning protrusion 131 is 0.05mm ≤ 0.15mm. Cell 3 (e.g. Figure 1 The flattened layer (as shown) has a recessed structure. After assembly, the positioning protrusion 13 is embedded in the recessed structure.
[0035] In another structure, such as Figure 3As shown, the anti-deflection positioning element 13 has at least three positioning ribs 132, all of which are located on the first surface and extend radially along the central hole 12. In this embodiment, there are at most eight positioning ribs 132, preferably six; the height of the positioning ribs 132 is 0.05mm ≤ 0.12mm.
[0036] In another structure, such as Figure 4 As shown, the anti-deflection positioning component 13 has at least twelve protruding teeth 133. All protruding teeth 133 are located on the side circumferential surface of the main body 11 and extend radially outward along the central hole 12. After assembly, the protruding teeth 133 engage with the inner wall of the cylindrical outer shell 2. In this embodiment, there are a maximum of twenty-four protruding teeth 133. The protruding teeth 133 are micro-tooths evenly distributed on the side circumferential surface of the main body 11, and the tooth height of the protruding teeth 133 is 0.05mm≤0.15mm≤0.15mm.
[0037] The three structures of the anti-deflection positioning component 13 can be used individually or in combination, depending on the specific requirements.
[0038] Based on the above structure, such as Figure 5 As shown, a chamfer 15 is protruding from the inner wall surface of the central hole 12, extending radially towards the center of the central hole 12. The function of the chamfer 15 is to prevent stress concentration at the edge of the central hole 12 from causing cracking of the insulating sheet. After the chamfer 15 is provided, no cracking or deformation occurs after fifty temperature cycles from -40℃ to 85℃. The specific dimensions of the chamfer 15 are not limited. In this embodiment, the angle of the chamfer 15 is 30° ≤ 60°, and the depth of the chamfer 15 is 0.1mm ≤ 0.3mm.
[0039] At 25℃, the volume resistivity of the positive electrode insulating sheet 1 is ≥10. 14 Ω·cm, surface resistivity ≥10 13 Ω / □; Volume resistivity ≥10 at high temperatures (e.g., 85℃) 12 Ω·cm.
[0040] In this embodiment, after the positive electrode insulating sheet 1 is immersed in the electrolyte (1MLiPF6 in EC / EMC / DEC) at 85°C for 168h, the mass increase rate of the positive electrode insulating sheet 1 is ≤3%, the tensile strength retention rate is ≥85%, the breakdown voltage retention rate is ≥90%, and the dimensional change rate is ≤0.5%.
[0041] like Figure 5 and Figure 6As shown, the surface of the sheet body 11 is coated with a ceramic coating 16, and the material used to prepare the ceramic coating 16 includes Al2O3 or SiO2; the breakdown voltage of the ceramic coating 16 is greater than or equal to a set value. The ceramic coating 16 makes the breakdown voltage ≥1.5kV, compared with only 1.0kV to 1.2kV for the uncoated PET sheet body 11. This positive electrode insulating sheet 1 has strong withstand voltage safety and is suitable for high-nickel high-voltage systems; the ceramic coating 16 improves the surface hardness of the sheet body 11 and prevents scratches.
[0042] The ceramic coating 16 has a thickness between 5 μm and 20 μm, preferably 12 μm, and is formed by dip coating or screen printing followed by baking and curing at 180℃ for 30 min. The ceramic coating 16 improves the voltage breakdown capability of the positive electrode insulating sheet 1 to ≥1.5kV, increases surface hardness and scratch resistance; the adhesion between the ceramic coating 16 and the sheet body 11 is ≥3B grade (ASTM D3359 cross-cut adhesion test); the ceramic coating 16 is hydrophilic, improving electrolyte wettability.
[0043] Based on the above structure, a sealing rib 14 is formed on the second surface and adjacent to the outer periphery of the sheet body 11. The sealing rib 14 protrudes from the second surface. It is understood that there is no specific numerical limitation on "adjacent". As long as the distance between the sealing rib 14 and the center point is greater than the distance between the sealing rib 14 and the outer periphery of the sheet body 11, it is not required that the sealing rib 14 be set at the outer edge of the sheet body 11. It is sufficient that it can play a sealing role.
[0044] The sealing rib 14 is designed to address the poor sealing performance of planar seals. The sealing rib 14 concentrates the sealing force onto a narrow band, forming a line seal. The local pressure is three to five times that of a planar seal, and it maintains excellent sealing performance, especially in high-temperature environments. For example, after storage at 85℃ for 168 hours, the residual sealing force decreases by only 10%–15%, which is better than the 40%–60% decrease of a planar seal; the residual compressive force is ≥0.5 × the initial compressive force.
[0045] The specific shape of the sealing rib 14 is not limited, as long as it can achieve local high-pressure "line sealing" and significantly reduce the sealing force attenuation rate. In one structure, such as... Figure 7 As shown, in the axial section of the sheet body 11, the sealing rib 14 is semi-circular, and the straight edge of the semi-circular structure is attached to the second surface. In another structure, as... Figure 8 As shown, the sealing rib 14 is trapezoidal, with the long side of the trapezoidal structure fitting against the second surface. In another structure, such as... Figure 9 As shown, the sealing rib 14 is triangular, and one side of the triangular structure is attached to the second surface.
[0046] The specific dimensions of the sealing rib 14 are not limited. In this embodiment, the height of the sealing rib 14 is between 0.08 mm and 0.25 mm, and the bottom width is between 0.2 mm and 0.6 mm. The preferred processing method for the sealing rib 14 is precision injection molding or hot pressing.
[0047] After assembly, the sealing rib 14 undergoes 20% to 50% compression deformation under the compression of the cap sealing ring 5, concentrating the sealing force in the narrow band to form a high-pressure sealing line. Even if the substrate undergoes creep, the residual sealing force in the sealing rib 14 area is still much higher than that of the surface sealing scheme. Figure 10 This is a schematic diagram comparing the high-temperature aging of the 14-line seal with the ribbed seal and the flat seal, that is, a schematic diagram showing the change of residual sealing force over time.
[0048] To improve sealing performance, in this embodiment, the sealing rib 14 is arranged in a ring around the center of the sheet body 11. That is, the sealing rib 14 is continuous along the circumference of the sheet body 11 without any breaks or gaps, and the continuous length accounts for 100% of the total circumference. The top surface of the sealing rib 14 is parallel to the second surface, that is, the height of each point on the top surface of the sealing rib 14 protruding from the second surface is basically the same, and the cross-sectional shape deviation is ≤0.02mm; at least twenty points are measured along the circumference, and the height consistency (CV) of the sealing rib 14 is ≤8%.
[0049] Based on the above structure, such as Figure 11 and Figure 12 As shown, at least four electrolyte channeling grooves 17 are formed on the second surface, and the electrolyte channeling grooves 17 extend radially outward from the center of the sheet body 11. Wherein, as... Figure 11 The electrolyte guide channel 17 shown is a single-line structure. Figure 12 The electrolyte channel 17 shown is a double-lined groove structure, extending from the central hole 12 to the outer edge of the sheet body 11 to promote end-face wetting and improve electrolyte wettability. In this embodiment, there are a maximum of twelve electrolyte channel 17s, all of which are evenly distributed; the width of the electrolyte channel 17 is 0.3mm ≤ 1.0mm, and the depth of the electrolyte channel 17 is 0.03mm ≤ 0.10mm.
[0050] The combination of electrolyte channel 17 and ceramic coating 16 provides better hydrophilicity, thereby improving the flow and wetting rate of electrolyte on the end face and shortening the injection time.
[0051] The following table summarizes the parameters: Example 1 This embodiment represents the optimal overall design: the sheet body 11 is made of PET, and features sealing ribs 14, radially arranged positioning ribs 132, and a ceramic coating 16. Specifically, the sheet body 11 is made of PET film with a thickness of 0.25 mm and an outer diameter of 20.0 mm; the sealing ribs 14 have a semi-circular cross-section, a height of 0.15 mm, a bottom width of 0.35 mm, and are continuous along the circumference without any breaks. The six positioning ribs 132 are radially arranged, with the same included angle between adjacent positioning ribs 132, and a height of 0.08 mm; the ceramic coating 16 is Al2O3-based, with a thickness of 12 μm and an adhesion rating of 4B; the central hole 12 has a diameter of 3.5 mm and a chamfer of 150.2 mm × 45°; and a total of eight electrolyte channeling grooves 17, each 0.5 mm wide and 0.05 mm deep.
[0052] Test results: Initial sealing force 0.35 N / mm, 0.31 N / mm after 85℃×168h (attenuation only 11%); assembly deflection angle 1.2° (<2° qualified); breakdown voltage 2.1kV (≥1.5kV qualified); volume resistivity 3.2×10 16 Ω·cm; mass increase of 1.8% after electrolyte immersion, tensile strength retention rate of 92%; no cracking or deformation after 50 cycles at -40℃ to 85℃; single piece weight of 0.12g; yield rate of 99.9%.
[0053] Example 2 This embodiment is a high-temperature resistant solution using PI material. Specifically, the main body 11 is made of PI film substrate with a thickness of 0.15mm. There is no ceramic coating 16 on the main body 11. The PI film substrate itself has a withstand voltage of ≥3kV. It is suitable for high-temperature batteries with an operating temperature >80℃.
[0054] Test results: Breakdown voltage 3.5kV, temperature resistance 200℃; single piece weight 0.08g, residual sealing force decay <10% after high temperature storage.
[0055] Example 3 This embodiment is a chemical resistance solution obtained by PPS injection molding. Specifically, the sheet body 11 is made of PPS injection molded sheet with a thickness of 0.35 mm, which is suitable for corrosive electrolyte systems containing hydrofluoric acid (HF) and other corrosive electrolytes.
[0056] Test results: After immersion in electrolyte, the mass increased by 0.5%, the breakdown voltage was 1.8kV, the mass of a single piece was 0.18g, and the dimensional change rate was <0.3%.
[0057] Example 4 This embodiment is a temperature / pressure resistance balanced solution obtained by using PEN material. Specifically, the sheet body 11 is made of PEN film substrate with a thickness of 0.20mm; the ceramic coating 16 is Al2O3 based with a thickness of 8μm, and its temperature and pressure resistance are between PET and PI.
[0058] Test results: Breakdown voltage 2.0kV, long-term operating temperature 155℃, high-temperature sealing attenuation 13%.
[0059] Example 5 This embodiment is a pressure-bearing and collapse-resistant scheme obtained by using a sealing rib 14 with a trapezoidal cross section. Specifically, the sealing rib 14 has a trapezoidal cross section with a height of 0.15mm and a bottom width of 0.5mm, resulting in a large pressure-bearing area and resistance to pressure collapse; the rest of the structure is the same as in Embodiment 1.
[0060] Test results: No collapse after 50% compression, rebound rate >90%; residual sealing force decreased by 10%.
[0061] Example 6 This embodiment uses a triangular sealing rib 14 to obtain a sharp line sealing solution. Specifically, the sealing rib 14 has a triangular cross-section with a height of 0.18 mm and a bottom width of 0.3 mm, resulting in the narrowest contact line and the highest unit pressure. The rest of the structure is the same as in Embodiment 1.
[0062] Test results: The local sealing pressure is about five times that of the planar seal, and the initial sealing force is 0.40 N / mm.
[0063] Example 7 This embodiment is a large tolerance compensation scheme obtained by using a high sealing rib 14. Specifically, the height of the sealing rib 14 is taken as the upper limit of 0.25 mm, which has a large compression stroke and strong ability to compensate for assembly tolerances; the rest of the structure is the same as in Embodiment 1.
[0064] Test results: The seal was maintained even with an assembly gap fluctuation of ±0.10mm, and the compression rate was 45%.
[0065] Example 8 This embodiment is a low-assembly-force, thin-film solution obtained by using a low-sealing rib 14. Specifically, the height of the sealing rib 14 is set to a lower limit of 0.08mm, resulting in low assembly clamping force and a thin structure; the rest of the structure is the same as in Embodiment 1.
[0066] Test results: Assembly pressure decreased by approximately 30%, suitable for thin / low-pressure applications, and residual sealing force decreased by 14%.
[0067] Example 9 This embodiment uses an annular anti-deflection positioning component 13. Specifically, the anti-deflection positioning component 13 includes at least two concentric annular positioning protrusions 131 surrounding the central hole 12. The height of the protrusion of the anti-deflection positioning component 13 protruding from the main body 11 is 0.12mm, which cooperates with the flattened layer recess of the battery cell 3; the rest of the structure is the same as in Embodiment 1.
[0068] Test results: Assembly deflection angle 1.0°, high positioning repeatability.
[0069] Example 10 In this embodiment, the anti-deflection positioning component 13 is used as an edge locking tooth scheme. Specifically, the anti-deflection positioning component 13 has eighteen protruding teeth 133 with a tooth height of 0.10mm, which mesh with the inner wall of the cylindrical outer shell 2; the rest of the structure is the same as in Embodiment 1.
[0070] Test results: Assembly deflection angle 0.9°, no displacement after handling vibration.
[0071] Example 11 This embodiment adopts a combined positioning method to achieve the strongest anti-deflection scheme. Specifically, the anti-deflection positioning component 13 includes a positioning rib 132 that is disposed on the first surface and extends radially, and a tooth 133 that is disposed on the side circumferential surface of the body 11 and extends radially outward. The rest of the structure is the same as in Embodiment 1.
[0072] Test results: Assembly deflection angle <1°, typically 0.6°; positioning defect rate of automated high-speed production line <0.02%.
[0073] Example 12 This embodiment uses a SiO2-based ceramic coating 16 to obtain a strongly hydrophilic solution. Specifically, the ceramic coating 16 has a thickness of 12μm and better hydrophilicity; the rest of the structure is the same as in Embodiment 1.
[0074] Test results: The electrolyte end-face wetting rate increased by about 25%, and the injection time was shortened; the breakdown voltage was 1.9kV.
[0075] Example 13 This embodiment is a high pressure-resistant solution obtained by using a thick ceramic coating 16. Specifically, the thickness of the ceramic coating 16 is taken as the upper limit of 20μm, which has the highest pressure resistance; the rest of the structure is the same as in Embodiment 1.
[0076] Test results: Breakdown voltage 2.5kV, compatible with high-nickel 4.4V system; adhesion ≥3B.
[0077] Example 14 This embodiment is a rapid electrolyte injection scheme using multiple electrolyte channel 17. Specifically, twelve electrolyte channel 17 are formed on the second surface. The width of the electrolyte channel 17 is 0.8 mm and the depth is 0.08 mm. The rest of the structure is the same as in Embodiment 1.
[0078] Test results: Injection time was shortened by approximately 30%; the end face was evenly wetted with no dry areas.
[0079] Example 15 This embodiment features a crack-resistant design with a large chamfer 15 protruding from the inner wall of the central hole 12. Specifically, the chamfer 15 has an angle of 60° and a depth of 0.3 mm, which significantly reduces the stress concentration factor. The rest of the structure is the same as in Embodiment 1.
[0080] Test results: No cracks were found in the central hole 12 after fifty temperature cycles; the edge of the central hole 12 showed the best crack resistance.
[0081] Example 16 This embodiment is a comprehensive mass production balance solution. Specifically, the sheet body 11 is made of PET with a thickness of 0.25 mm and an outer diameter of 20.0 mm; the sealing rib 14 is semi-circular with a height of 0.15 mm and a bottom width of 0.35 mm; six radial positioning ribs 132 are provided on the sheet body 11; the Al2O3-based ceramic coating 16 has a thickness of 12 μm; eight electrolyte guide grooves 17 are formed on the second surface; a balance is achieved between sealing, insulation, wetting and cost, oriented towards mass production.
[0082] Test results: High temperature sealing degradation 11%, deflection angle 1.2°, breakdown voltage 2.1kV, yield 99.9%.
[0083] The table below compares the structural and material parameters of the above embodiments: The table below compares the features and test results of the above embodiments: To fully demonstrate the critical significance of the structural features and parameter ranges of the positive electrode insulating sheet, the following eight sets of comparative embodiments are provided to verify the necessity of the corresponding technical features. It is understood that, unless otherwise specified, each embodiment is based on Embodiment 1, with only the single feature under investigation changed or deviated from the scope of the claims.
[0084] Comparative Example 1 This comparative embodiment compares planar sealing. Specifically, the sealing rib 14 is removed and replaced with a planar overall compression seal. The rest of the structure is the same as in Embodiment 1.
[0085] Test results: After 85℃ for 168 hours, the residual sealing force was only 0.15 N / mm (attenuation of approximately 57%), indicating leakage after long-term use at high temperatures. This confirms the crucial role of the line seal of sealing rib 14 in maintaining a high-temperature seal.
[0086] Comparative Example 2 This comparative embodiment omits the anti-deflection positioning component 13, while the rest of the structure is the same as in Embodiment 1.
[0087] Test results: The deflection angle of the automated assembly reached 8° to 12°, and some areas did not cover the edge of the positive current collector 4. The short circuit failure rate was 0.1% to 0.3%. This confirms the necessity of the anti-deflection positioning component 13.
[0088] Comparative Example 3 This comparative example has no ceramic coating 16, uses ordinary PET to prepare the sheet body 11, and the rest of the structure is the same as in Example 1.
[0089] Test results: The breakdown voltage is only 1.0–1.2 kV, posing a risk of insulation breakdown and short circuit in high-nickel (NCM811 / NCA, >4.3V) systems. This confirms the necessity of the 16-pair withstand voltage safety of the ceramic coating.
[0090] Comparative Example 4 This comparative embodiment uses an excessively high sealing rib 14. Specifically, the height of the sealing rib 14 is >0.25mm, and the rest of the structure is the same as in Embodiment 1.
[0091] Test results: The sealing rib 14 is easily crushed and loses its resilience under compression, resulting in a decrease in sealing force. This confirms the necessity of limiting the upper limit of the height of the sealing rib 14.
[0092] Comparative Example 5 This comparative embodiment uses a low sealing rib 14. Specifically, the height of the sealing rib 14 is <0.08mm, and the rest of the structure is the same as in Embodiment 1.
[0093] Test results: Insufficient sealing force, leakage after high-temperature creep. This confirms the necessity of limiting the lower limit of the height of the sealing rib 14.
[0094] Comparative Example 6 The outer diameter of the main body 11 in this comparative embodiment is too small. Specifically, the outer diameter of the main body 11 is <19.0mm and the outer diameter of the main body 11 is <the outer diameter of the positive current collector 4. The rest of the structure is the same as in Embodiment 1.
[0095] Test results: The edge of the positive current collector 4 was not covered, which may have caused a short circuit due to contact with the battery cell 3. This confirms the necessity of limiting the lower limit of the outer diameter of the main body 11 and requiring the main body 11 to cover the edge of the positive current collector 4.
[0096] Comparative Example 7 The thickness of the sheet body 11 in this comparative embodiment is too thin. Specifically, the thickness of the sheet body 11 is <0.15mm, and the rest of the structure is the same as in Embodiment 1.
[0097] Test results: Insufficient insulation withstand voltage (breakdown voltage < 1 kV), posing a short circuit risk. This confirms the necessity of setting a lower limit for the thickness of the sheet body 11.
[0098] Comparative Example 8 The compression ratio of the sealing rib 14 in this comparative embodiment is too large. Specifically, the compression ratio of the sealing rib 14 is >50%, and the rest of the structure is the same as in Embodiment 1.
[0099] Test results: Sealing rib 14 showed permanent deformation and severe stress relaxation, losing its resilience and long-term sealing ability. This confirms the necessity of setting an upper limit for the compression ratio.
[0100] The table below compares the failure modes of the above comparative embodiments with the key features of the invention: The table below shows the hazards and consequences when each key parameter exceeds its optimal range: Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.
Claims
1. A positive electrode insulating sheet for a cylindrical battery, comprising a sheet-shaped sheet body (11), said sheet body (11) including a first surface and a second surface disposed opposite to each other, characterized in that, An anti-deflection positioning member (13) is formed on the first surface or the side peripheral surface of the sheet body (11), the anti-deflection positioning member (13) can make the assembly deflection angle of the positive electrode insulating sheet (1) less than a set value.
2. The positive electrode insulating sheet for a cylindrical battery according to claim 1, characterized in that, The main body (11) has a central hole (12) in the middle, and the anti-deflection positioning member (13) is at least one annular positioning protrusion (131). All of the positioning protrusions (131) are located on the first surface and concentrically surround the central hole (12); and / or, The anti-deflection positioning element (13) consists of at least three positioning ribs (132), all of which are located on the first surface and extend radially along the central hole (12); and / or, The anti-deflection positioning element (13) has at least twelve protruding teeth (133), all of which are located on the side circumferential surface of the sheet body (11) and extend outward radially along the central hole (12).
3. The positive electrode insulating sheet for a cylindrical battery according to claim 2, characterized in that, A chamfer (15) is provided on the inner wall surface of the central hole (12), and the chamfer (15) extends radially from the inner wall surface of the central hole (12) toward the center of the central hole (12).
4. The positive electrode insulating sheet for a cylindrical battery according to claim 1, characterized in that, A sealing rib (14) is formed on the second surface and near the outer periphery of the sheet body (11), the sealing rib (14) protruding from the second surface.
5. The positive electrode insulating sheet for a cylindrical battery according to claim 4, characterized in that, In the axial section of the sheet body (11), the sealing rib (14) is semi-circular, and the straight edge of the semi-circular structure is attached to the second surface; or, The sealing rib (14) is trapezoidal, with the long side of the trapezoidal structure fitting against the second surface; or, The sealing rib (14) is triangular, with one side of the triangular structure attached to the second surface.
6. The positive electrode insulating sheet for a cylindrical battery according to claim 4, characterized in that, The sealing rib (14) is arranged in a ring around the center of the sheet body (11), and the top surface of the sealing rib (14) is parallel to the second surface.
7. The positive electrode insulating sheet for a cylindrical battery according to any one of claims 1 to 6, characterized in that, The sheet body (11) is made of polyethylene terephthalate, polyethylene naphthalate, polyimide or polyphenylene sulfide.
8. The positive electrode insulating sheet for a cylindrical battery according to any one of claims 1 to 6, characterized in that, The surface of the sheet body (11) is coated or screen-printed and then baked to form a ceramic coating (16). The material used to prepare the ceramic coating (16) includes Al2O3 or SiO2. The breakdown voltage of the ceramic coating (16) is greater than or equal to a set value.
9. The positive electrode insulating sheet for a cylindrical battery according to any one of claims 1 to 6, characterized in that, At least four electrolyte channel grooves (17) are formed on the second surface, the electrolyte channel grooves (17) extending radially outward from the center of the sheet body (11).
10. A cylindrical lithium-ion battery, comprising a cylindrical casing (2), a battery cell (3), a positive electrode current collector (4), and a cap sealing ring (5), wherein the battery cell (3), the positive electrode current collector (4), and the cap sealing ring (5) are sequentially disposed within the cylindrical casing (2), characterized in that, The cylindrical lithium-ion battery further includes a positive electrode insulating sheet (1) as described in any one of claims 1 to 9, wherein the positive electrode insulating sheet (1) is disposed in the cylindrical shell (2) and located between the positive electrode current collector (4) and the cap sealing ring (5), wherein the outer diameter of the positive electrode current collector (4) is less than the outer diameter of the positive electrode insulating sheet (1) and the inner diameter of the cylindrical shell (2).