Cylindrical battery cap assembly and cylindrical secondary battery

Abstract

The utility model relates to a cylindrical battery cap assembly and a cylindrical secondary battery, and belongs to the technical field of batteries. Wherein the cylindrical battery cap assembly comprises an anti-explosion sheet, an inner rubber ring and a lower end plate; a lug boss is arranged at the bottom of the anti-explosion sheet, and a positioning cavity with a downward opening is defined by the lug boss; the peripheral wall of the inner rubber ring makes contact with the side, facing the positioning cavity, of the protruding part. A mounting cavity is defined by the inner rubber ring, an opening of the mounting cavity faces downwards, a limiting part is arranged on the inner peripheral wall of the mounting cavity, and the limiting part is arranged on the inner peripheral wall of the mounting cavity in a protruding mode; a gap is formed between the limiting part and the top wall of the mounting cavity; the lower end plate is arranged in the mounting cavity, and the outer edge of the lower end plate is arranged in the gap. According to the cylindrical battery cap assembly provided by the utility model, the lower end plate and the inner rubber ring can be concentric, and the lower end plate is fixed by utilizing the inner rubber ring, so that the lower end plate can be buffered to a certain degree under the working condition of frequent vibration, and a welding printing area between the lower end plate and the anti-explosion sheet is not easy to pull.

Description

Technical Field

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

[0002] Existing battery caps typically include an explosion-proof sheet, a lower end plate, and an inner rubber ring. The explosion-proof sheet serves as a safety protection device, capable of rupturing and releasing pressure in a timely manner when the internal pressure of the battery abnormally increases, effectively preventing battery explosion accidents. The lower end plate has a dual function: preventing electrolyte leakage and maintaining the stability of the internal chemical environment of the battery. The inner rubber ring is responsible for isolating components with different potentials inside the battery, preventing short circuits, and ensuring the safe operation of the battery.

[0003] However, existing battery cap designs have certain flaws: there is no fixed positional relationship between the lower end plate and the inner rubber ring; the inner rubber ring is only secured by the gap between the lower end plate and the explosion-proof sheet. This design means the inner rubber ring cannot effectively fix or limit the lower end plate, requiring specialized equipment for positioning to achieve concentric assembly. Furthermore, when the battery is used in environments with frequent vibrations, the inner rubber ring is prone to displacement. Simultaneously, continuous vibration can cause repeated pulling on the weld points between the lower end plate and the explosion-proof sheet, potentially leading to weld detachment and cap failure.

[0004] A battery cap (publication number CN108598300A) discloses a stepped structure for the explosion-proof sheet, where the middle portion of the sheet protrudes downwards. A groove is provided on the top of the inner rubber ring, allowing the protrusion of the explosion-proof sheet to be positioned within the groove, thus achieving positioning between the explosion-proof sheet and the inner rubber ring. While this method provides good positioning, the large size of the protrusion and groove increases the complexity of the explosion-proof sheet and inner rubber ring structure, making manufacturing difficult. Furthermore, the inner rubber ring typically needs to deform to fit the groove around the protrusion. During the interaction between the protrusion and the groove, the inner rubber ring may fail, increasing the size of the groove and reducing the positioning effectiveness between the inner rubber ring and the explosion-proof sheet.

[0005] In view of the above, this application is hereby submitted. Utility Model Content

[0006] To address the shortcomings of related technologies, this utility model provides a cylindrical battery cap assembly and a cylindrical secondary battery. By providing a protrusion, the protrusion forms a positioning cavity, allowing the inner rubber ring to be inserted into the positioning cavity, thereby connecting the inner rubber ring and the explosion-proof sheet. By providing a limiting part on the inner wall of the inner rubber ring, the limiting part protrudes from the inner peripheral wall of the mounting cavity, so that the limiting part supports and blocks the lower end plate, thereby installing the lower end plate in the mounting cavity and increasing the firmness of the connection between the lower end plate and the inner rubber ring.

[0007] This utility model provides a cylindrical battery cap assembly, comprising:

[0008] The explosion-proof sheet has a protrusion at the bottom, which defines a positioning cavity with its opening facing downwards.

[0009] The inner rubber ring has its outer peripheral wall in contact with the side of the protrusion facing the positioning cavity; the inner rubber ring defines an installation cavity with its opening facing downward, and the inner peripheral wall of the installation cavity has a limiting part that protrudes from the inner peripheral wall of the installation cavity; there is a gap between the limiting part and the top wall of the installation cavity.

[0010] The lower end plate is located inside the mounting cavity, and its outer edge is located within the gap.

[0011] This technical solution features a protrusion that forms a positioning cavity, allowing the inner rubber ring to be inserted into the positioning cavity, thus connecting the inner rubber ring and the explosion-proof sheet. A limiting part is provided on the inner wall of the inner rubber ring, protruding from the inner circumferential wall of the mounting cavity. This limiting part supports and blocks the lower end plate, ensuring the lower end plate is installed within the mounting cavity and increasing the strength of the connection between the lower end plate and the inner rubber ring.

[0012] In some embodiments, the limiting part is located at the opening of the mounting cavity; the thickness of the peripheral wall at the middle of the mounting cavity is L1, and the thickness between the side of the limiting part facing the mounting cavity and the outer peripheral wall of the inner rubber ring is L2, and the ratio of L1 to L2 is greater than or equal to 64% and less than or equal to 84%.

[0013] In some embodiments, the height of the protrusion is H1, the height of the inner rubber ring is H2, and the ratio of H1 to H2 is greater than or equal to 52% and less than or equal to 72%.

[0014] In some embodiments, the height between the top of the limiting part and the top wall of the mounting cavity is H3, and the ratio of H3 to the height H2 of the inner rubber ring is greater than or equal to 21% and less than or equal to 41%.

[0015] In some embodiments, an extension is provided at the outer edge of the lower end plate. The thickness of the extension is less than the thickness of the outer edge of the lower end plate, and the extension is located at the upper end of the outer edge of the lower end plate. The extension is disposed within the gap. When the extension is disposed within the gap, the distance L3 between the limiting part and the lower peripheral wall at the outer edge of the lower end plate satisfies: 0.1mm≤L3≤0.3mm; the distance S1 from the outer edge of the extension to the inner wall of the mounting cavity satisfies: 0.03mm≤S1≤0.1mm.

[0016] In some embodiments, the top surface of the extension is flush with the top surface of the lower end plate; the ratio of the thickness H4 of the extension to the thickness H5 of the outer edge of the lower end plate is greater than or equal to 40% and less than or equal to 60%.

[0017] In some embodiments, the ratio of the height H2 of the inner rubber ring to the thickness H6 of the top wall of the mounting cavity is greater than or equal to 200% and less than or equal to 240%.

[0018] In some embodiments, an included angle α is defined between the outer peripheral wall of the protrusion and the bottom surface of the explosion-proof sheet, and the included angle α satisfies: 95°≤α≤125°.

[0019] In some embodiments, the top wall of the mounting cavity is provided with a first vent hole for air to pass through, and the first vent hole is arranged in a vertical direction; the thickness of the peripheral wall of the mounting cavity is L1, the distance between the peripheral wall of the inner rubber ring and the hole wall of the first vent hole is L4, and the ratio of L1 to L4 is greater than or equal to 23% and less than or equal to 33%.

[0020] In addition, this utility model also provides a cylindrical secondary battery, including the above-mentioned cylindrical battery cap assembly.

[0021] Based on the above technical solution, in this embodiment of the utility model, the cylindrical battery cap assembly has a protrusion that forms a positioning cavity, allowing the inner rubber ring to be inserted into the positioning cavity, thus connecting the inner rubber ring and the explosion-proof sheet. A limiting part is provided on the inner wall of the inner rubber ring, protruding from the inner circumferential wall of the mounting cavity. This limiting part supports and blocks the lower end plate, ensuring the lower end plate is installed within the mounting cavity and increasing the strength of the connection between the lower end plate and the inner rubber ring. Not only can the lower end plate and the inner rubber ring achieve concentricity, eliminating the need for excessive additional equipment investment and saving manufacturing costs, but the inner rubber ring also provides cushioning for the lower end plate under frequent vibration conditions, preventing tearing of the weld area between the lower end plate and the explosion-proof sheet, thus ensuring the reliability of the weld. Attached Figure Description

[0022] The accompanying drawings, which are included to provide a further understanding of the present invention and form part of this application, illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the present invention and do not constitute an undue limitation thereof. In the drawings:

[0023] Figure 1 This is a schematic diagram of the structure of one embodiment of the cylindrical battery cap assembly of this utility model;

[0024] Figure 2 for Figure 1 Enlarged view of a portion of point A in the middle;

[0025] Figure 3 This is a schematic diagram of the explosion-proof sheet in one embodiment of the cylindrical battery cap assembly of this utility model;

[0026] Figure 4 This is a schematic diagram of the inner rubber ring in one embodiment of the cylindrical battery cap assembly of this utility model;

[0027] Figure 5 This is a partial dimensional diagram of one embodiment of the cylindrical battery cap assembly of this utility model;

[0028] Figure 6 This is another dimensional diagram of an embodiment of the cylindrical battery cap assembly of this utility model.

[0029] In the picture:

[0030] 1. Explosion-proof sheet; 2. Inner rubber ring; 3. Lower end plate;

[0031] 11. Protrusion; 12. Positioning cavity;

[0032] 21. Limiting part; 22. First vent hole; 23. Mounting cavity; 24. Gap;

[0033] 31. Extension; 32. Second vent. Detailed Implementation

[0034] The technical solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0035] In the description of this utility model, it should be understood that the terms "center", "lateral", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model 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 utility model.

[0036] The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature.

[0037] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0038] As attached Figures 1-4 As shown in an illustrative embodiment of the cylindrical battery cap assembly of this utility model, the cylindrical battery cap assembly includes an explosion-proof sheet 1, an inner rubber ring 2, and a lower end plate 3; the bottom of the explosion-proof sheet 1 is provided with a protrusion 11, the protrusion 11 extends in the circumferential direction, and the protrusion 11 and the explosion-proof sheet 1 together define a positioning cavity 12 with the opening facing downward; the outer peripheral wall of the inner rubber ring 2 is in contact with the side of the protrusion 11 facing the positioning cavity 12; the inner rubber ring 2 defines a mounting cavity 23, the opening of the mounting cavity 23 is provided downward, and the inner peripheral wall of the mounting cavity 23 is provided with a limiting part 21, the limiting part 21 protruding from the inner peripheral wall of the mounting cavity 23; there is a gap 24 between the limiting part 21 and the top wall of the mounting cavity 23; the lower end plate 3 is disposed in the mounting cavity 23, and the outer edge of the lower end plate 3 is disposed within the gap 24.

[0039] The aforementioned cylindrical battery cap assembly features a protrusion 11 that surrounds a positioning cavity 12, allowing the inner rubber ring 2 to be inserted into the positioning cavity 12, thus connecting the inner rubber ring 2 with the explosion-proof sheet 1. A limiting part 21 is provided on the inner wall of the inner rubber ring 2, protruding from the inner circumferential wall of the mounting cavity 23. This limiting part 21 supports and blocks the lower end plate 3, thereby ensuring the lower end plate 3 is installed within the mounting cavity 23 and increasing the firmness of the connection between the lower end plate 3 and the inner rubber ring 2.

[0040] like Figure 4 As shown, the limiting part 21 is located at the opening of the mounting cavity 23. There is a gap 24 between the top of the limiting part 21 and the top surface of the mounting cavity 23 to form a slot. The slot is arranged along the circumference of the mounting cavity 23. When the lower end plate 3 is assembled with the inner rubber ring 2, the outer edge of the lower end plate 3 is inserted into the slot, and the limiting part 21 and the bottom surface of the lower end plate 3 are in contact with each other to prevent the lower end plate 3 from detaching from the mounting cavity 23.

[0041] It should be noted that the inner rubber ring 2 is made of plastic or similar material. By deforming the inner rubber ring 2, it can be inserted into the positioning cavity 12, thus assembling the inner rubber ring 2 with the explosion-proof sheet 1. By deforming the inner rubber ring 2, the lower end plate 3 can be positioned within the gap 24, thereby allowing the lower end plate 3 to be installed in the mounting cavity 23, thus assembling the lower end plate 3 with the inner rubber ring 2.

[0042] like Figure 5As shown, the thickness of the peripheral wall at the middle of the mounting cavity 23 is L1, and L1 satisfies: 0.21mm≤L1≤0.41mm, so that the inner rubber ring 2 has greater strength.

[0043] If L1 < 0.21 mm, the peripheral wall of the mounting cavity 23 is relatively thin, and the peripheral wall of the mounting cavity 23 is easily damaged when the inner rubber ring 2 deforms; if L1 > 0.41 mm, the peripheral wall of the mounting cavity 23 is relatively thick, and the peripheral wall of the mounting cavity 23 is not easily deformed, which may increase the difficulty of setting the outer edge of the lower end plate 3 within the gap 24.

[0044] like Figure 5 As shown, the thickness of the limiting part 21 from the side facing the mounting cavity 23 to the outer peripheral wall of the inner rubber ring 2 is L2. L2 satisfies: 0.34mm≤L2≤0.52mm, so that the contact area between the limiting part 21 and the lower end plate 3 is larger, thereby increasing the blocking effect of the limiting part 21 on the lower end plate 3.

[0045] If L2 < 0.34 mm, the radial dimension of the limiting part 21 along the inner rubber ring 2 is small, the contact area between the limiting part 21 and the lower end plate 3 is small, and the blocking effect of the limiting part 21 on the lower end plate 3 is reduced; if L2 > 0.52 mm, the radial dimension of the limiting part 21 along the inner rubber ring 2 is large, the contact area between the limiting part 21 and the lower end plate 3 is large, and the inner rubber ring 2 needs to undergo a large deformation to make the outer edge of the lower end plate 3 located within the gap 24.

[0046] In some embodiments, H1 is 0.5 mm and H2 is 0.8 mm.

[0047] The ratio of L1 to L2 is greater than or equal to 64% and less than or equal to 84%, so that the limiting part 21 and the lower end plate 3 have a large contact area, so that the limiting part 21 has a good blocking effect on the lower end plate 3, and the lower end plate 3 is easier to set in the slot.

[0048] If the ratio of L1 to L2 is too small, the strength of the limiting part 21 will be low, and the limiting part 21 will be easily deformed, causing the limiting part 21 to fail to hold the edge of the lower end plate 3. If the ratio of L1 to L2 is too large, the inner diameter of the gap 24 will be small, and there will not be enough internal space in the mounting cavity 23 to hold the lower end plate 3. After L2 becomes smaller, the lower end plate 3 will easily separate from the limiting part 21.

[0049] In some embodiments, the ratio of L1 to L2 is 70%.

[0050] like Figure 5 As shown, the height of the protrusion 11 is H1, and H1 satisfies: 0.4mm≤H1≤0.6mm, so that the inner wall of the protrusion 11 and the inner rubber ring 2 have a larger mating area, thereby increasing the firmness of the connection between the inner rubber ring 2 and the explosion-proof sheet 1.

[0051] If H1 < 0.4 mm, the height of the protrusion 11 is small, the mating area between the inner wall of the protrusion 11 and the inner rubber ring 2 is small, and the inner rubber ring 2 and the explosion-proof sheet 1 may not be firmly connected; if H1 > 0.6 mm, the height of the protrusion 11 is large, the mating area between the inner wall of the protrusion 11 and the inner rubber ring 2 is large, which may increase the assembly difficulty of the inner rubber ring 2 and the explosion-proof sheet 1.

[0052] like Figure 6 As shown, the height of the inner rubber ring 2 is H2, which satisfies: 0.7mm≤H2≤0.9mm, so that the inner rubber ring 2 and the protrusion 11 have a large mating area and the assembly between the inner rubber ring 2 and the protrusion 11 is less difficult.

[0053] If H2 < 0.7 mm, the height of the inner rubber ring 2 is small, and the mating area between the inner rubber ring 2 and the protrusion 11 is small; if H2 > 0.9 mm, the height of the inner rubber ring 2 is large, and the mating area between the inner rubber ring 2 and the protrusion 11 is large.

[0054] The ratio of H1 to H2 is greater than or equal to 52% and less than or equal to 72%, so that the protrusion 11 has a better fixing effect on the inner rubber ring 2, and the assembly difficulty between the protrusion 11 and the inner rubber ring 2 is small.

[0055] If the ratio of H1 to H2 is too small, the height difference between the protrusion 11 and the inner rubber ring 2 will be large. Since the function of the protrusion 11 is to fix the inner rubber ring 2 so that the inner rubber ring 2 will not wobble or shift, and to keep the inner rubber ring 2 concentric with other circular parts, if the height difference between the protrusion 11 and the inner rubber ring 2 is too large, the contact area of ​​the protrusion 11 fixing the inner rubber ring 2 will become smaller, resulting in a smaller force of the protrusion 11 fixing the inner rubber ring 2, which will make the inner rubber ring 2 prone to wobble and shift.

[0056] If the ratio of H1 to H2 is too large, the height difference between the protrusion 11 and the inner rubber ring 2 will be small. However, since the function of the protrusion 11 is to limit the inner rubber ring 2, if the height of the protrusion 11 is too high, it will increase the manufacturing difficulty of the explosion-proof sheet 1 and increase the weight of the cap, which will reduce the energy density of the battery.

[0057] In some embodiments, the ratio of H1 to H2 is 60%.

[0058] like Figure 6 As shown, the height between the top of the limiting part 21 and the top wall of the mounting cavity 23 is H3, and H3 satisfies: 0.15mm≤H3≤0.35mm, that is, the height of the gap 24 is 0.15mm~0.35mm, so that the outer edge of the lower end plate 3 can be provided in the slot.

[0059] In some embodiments, H3 is 0.2 mm.

[0060] The ratio of H3 to the height H2 of the inner rubber ring 2 is greater than or equal to 21% and less than or equal to 41%.

[0061] If the ratio of H3 to H2 is too small, H3 will decrease and H2 will increase accordingly. This will increase the thickness of the inner rubber ring 2, leading to increased weight, higher material costs, and higher battery manufacturing costs. Furthermore, a smaller H3 will reduce the height of the slot, making it difficult to properly insert the lower end plate 3 or secure it in place. The lower end plate 3 may become unstable during fixation and easily detach under vibration. In high-frequency vibration scenarios, if the lower end plate 3 detaches and shakes inside the battery, it will affect the welded connection between the middle part and the explosion-proof sheet 1, eventually causing the weld to detach, tear, or other problems, resulting in battery overheating or direct failure.

[0062] If the ratio of H3 to H2 is too large, then H3 becomes larger and H2 correspondingly smaller, resulting in thinner upper and lower wall thicknesses of the inner rubber ring 2. Since the inner rubber ring 2 is weaker and its wall thickness is thinner, the strength of the limiting part 21 decreases, and the limiting part 21 cannot reliably block the lower end plate 3. Conversely, if the height of the slot is too large, it may fail to hold the lower end plate 3, and the limiting part 21 will not effectively limit the lower end plate 3. This not only wastes materials but also increases the manufacturing cost of the battery, increases the weight of the cap, and reduces the energy density of the battery.

[0063] In some embodiments, the ratio of H3 to H2 is 30%.

[0064] like Figure 2 and Figure 5 As shown, an extension 31 is provided at the outer edge of the lower end plate 3. The thickness of the extension 31 is less than the thickness of the outer edge of the lower end plate 3, and the extension 31 is located at the upper end of the outer edge of the lower end plate 3. The extension 31 is provided in the gap 24 so that the lower end plate 3 and the inner rubber ring 2 can be assembled together.

[0065] like Figure 6 As shown, when the extension 31 is provided within the gap 24, the distance L3 between the limiting part 21 and the lower peripheral wall at the outer edge of the lower end plate 3 satisfies: 0.1mm≤L3≤0.3mm.

[0066] If L3 < 0.1mm, the strength of the extension 31 is relatively low. Since the inner rubber ring 2 is made of plastic and has a groove design, when assembling the lower end plate 3, the edge of the lower end plate 3 needs to be squeezed into the groove of the inner rubber ring 2 to achieve fixation of the lower end plate 3. During the squeezing process of the inner rubber ring 2, the inner rubber ring 2 will deform, and the material will be squeezed and flow towards the edge, which may interfere with the lower end plate 3, causing assembly difficulties and reducing assembly efficiency.

[0067] If L3 > 0.3mm, the strength of the limiting part 21 will decrease, making it prone to deformation. The edge of the lower end plate 3 needs to be inserted into the groove of the inner rubber ring 2 and should not easily slip out. However, with reduced strength, the edge of the lower end plate 3 is prone to deformation and slips out of the inner rubber ring 2 more easily. Under frequent vibration conditions, the lower end plate 3 is prone to frequent shaking, which will pull on the weld between the middle and the explosion-proof sheet 1, causing the weld to fall off and the battery to fail.

[0068] In some embodiments, L3 is 0.2 mm.

[0069] like Figure 6 As shown, the distance S1 from the outer edge of the extension 31 to the inner wall of the mounting cavity 23 satisfies: 0.03mm≤S1≤0.1mm.

[0070] If S1 < 0.03mm, since the lower end plate 3 and the inner rubber ring 2 are individual parts with tolerances during the manufacturing process, there will be tolerance accumulation during assembly. In addition, the material of the inner rubber ring 2 is plastic, which limits the dimensional tolerance range of the entire part. If the reserved gap S1 24 is too small, it is easy to cause an interference fit due to the accumulation of tolerances, which will increase the assembly difficulty and make it difficult to achieve mass production.

[0071] If S1 > 0.1mm, the lower end plate 3 may not fit into the mounting cavity 23, or it may slide out of the mounting cavity 23 after assembly, causing the function of fixing and limiting the lower end plate 3 to fail. Under the condition of frequent vibration, the lower end plate 3 is prone to frequent shaking, which will pull the weld between the middle and the explosion-proof sheet 1, causing the weld to fall off and the battery to fail.

[0072] In some embodiments, S1 is 0.05 mm.

[0073] like Figure 6 As shown, the top surface of the extension 31 is flush with the top surface of the lower end plate 3; the thickness H4 of the extension 31 satisfies: 0.15mm≤H4≤0.35mm. The thickness H5 of the outer edge of the lower end plate 3 satisfies: 0.4mm≤H5≤0.6mm.

[0074] The ratio of the thickness H4 of the extension 31 to the thickness H5 of the outer edge of the lower end plate 3 is greater than or equal to 40% and less than or equal to 60%.

[0075] If the ratio of H4 to H5 is too small, then H4 is too small and H5 is too large. This will reduce the strength of the limiting part 21, making it prone to deformation. H4 needs to be inserted into the groove of the inner rubber ring 2 and is not easy to slip out. However, with reduced strength, H4 is prone to deformation and can easily slip out of the inner rubber ring 2. Furthermore, if H5 is too large, it will increase the weight of the lower end plate 3, increase material usage, increase material costs, and decrease the energy density of the battery. If the ratio is too large, then H4 is too large and H5 is too small. This will increase the height of the limiting part 21, increase the material usage of the inner rubber ring 2, increase material costs, and decrease the energy density of the battery.

[0076] In some embodiments, H4 is 0.2 mm, H5 is 0.5 mm, and the ratio of H4 to H5 is 50%.

[0077] The ratio of the height H2 of the inner rubber ring 2 to the thickness H6 of the top wall of the mounting cavity 23 is greater than or equal to 200% and less than or equal to 240%.

[0078] If the ratio of H2 to H6 is too small, then H2 is too small, resulting in an insufficient height of the limiting part 21 and a reduced thickness of the slot. This prevents the lower end plate 3 from properly fitting into the slot, potentially causing it to become unstable during fixation and easily detach under vibration. In high-frequency vibration environments, this detachment can cause the lower end plate 3 to wobble inside the battery, potentially damaging the weld joint with the explosion-proof sheet 1, leading to weld detachment, tearing, and even battery overheating or failure. Conversely, if the ratio of H2 to H6 is too large, then H2 is too large, resulting in an excessively large height of the limiting part 21. When the outer edge of the lower end plate 3 is positioned within the slot, the limiting part 21 cannot effectively secure it. This not only wastes material on the inner rubber ring 2, increasing battery manufacturing costs, but also increases the weight of the cap and reduces the battery's energy density.

[0079] In some embodiments, the ratio of H2 to H6 is 230%.

[0080] An included angle α is formed between the outer peripheral wall of the protrusion 11 and the bottom surface of the explosion-proof sheet 1, and the included angle α satisfies: 95°≤α≤125°.

[0081] If the included angle α is too small, the purpose of the protrusion 11 is to fix and limit the inner rubber ring 2. However, because the included angle α is too small, it is impossible to fix and limit the inner rubber ring 2, causing the inner rubber ring 2 to be in a free state inside and prone to displacement. In this case, the function of the protrusion 11 is lost, and the protrusion 11 becomes meaningless and ineffective, increasing the weight and material cost of the cap and causing a decrease in the energy density of the battery. If the included angle α is too large, it is difficult to shape the protrusion 11 of the explosion-proof sheet 1, and when the angle is large, the strength of the material will decrease, and the ability to fix and limit the inner rubber ring 2 will decrease.

[0082] In some embodiments, the included angle α is 100°.

[0083] like Figure 4 and Figure 6 As shown, the top wall of the mounting cavity 23 is provided with a first vent 22 for air to pass through, and the first vent 22 is arranged in the vertical direction; the lower end plate 3 is provided with a second vent 32, which is arranged corresponding to the first vent 22, so that the gas inside the battery can come into contact with the explosion-proof sheet 1 through the second vent 32 and the first vent 22.

[0084] The distance between the peripheral wall of the inner rubber ring 2 and the wall of the vent hole is L4, and L4 satisfies: 0.8mm≤L4≤1.5mm.

[0085] If L4 < 0.8 mm, the distance from the first vent 22 to the outer peripheral wall of the inner rubber ring 2 is relatively short, and the strength of the inner rubber ring 2 is low; if L4 > 1.5 mm, the distance from the first vent 22 to the outer peripheral wall of the inner rubber ring 2 is relatively long, and although the strength of the inner rubber ring 2 is greater, the manufacturing cost of the inner rubber ring 2 is high.

[0086] In some embodiments, L4 is 1 mm.

[0087] The ratio of L1 to L4 is greater than or equal to 23% and less than or equal to 33%.

[0088] If the ratio of L1 to L4 is too small, the limiting part 21 serves to fix the lower end plate 3, limiting and fixing it. However, if the ratio of L1 to L4 is small, the overall strength of the limiting part 21 will be weakened, and its ability to fix the lower end plate 3 will be reduced. The lower end plate 3 may slip out of the slot due to lack of fixation. If used under conditions of frequent vibration, the lower end plate 3 may easily detach from the slot and shake inside the battery, constantly pulling on the weld between the lower end plate 3 and the explosion-proof sheet 1, causing problems such as tearing and breakage at the weld. If the ratio of L1 to L4 is too large, the limiting part 21 will be too thick. The limiting ability of the protrusion 11 on the inner rubber ring 2 needs to be strengthened, and the thickness of the protrusion 11 needs to be increased, which will increase the material cost and manufacturing difficulty, as well as the cost and weight of the cap, resulting in a decrease in the energy density of the battery.

[0089] Based on the above-described cylindrical battery cap assembly, this utility model also provides a cylindrical secondary battery, which includes the above-described cylindrical battery cap assembly.

[0090] Through the description of several embodiments of the cylindrical battery cap assembly of this utility model, it can be seen that the embodiments of the cylindrical battery cap assembly of this utility model have at least one or more of the following advantages:

[0091] (1) By setting the protrusion 11, the protrusion 11 surrounds and forms the positioning cavity 12, so that the inner rubber ring 2 is inserted into the positioning cavity 12 to realize the connection between the inner rubber ring 2 and the explosion-proof sheet 1; by setting the limiting part 21 on the inner wall of the inner rubber ring 2, the limiting part 21 protrudes from the inner peripheral wall of the mounting cavity 23 so that the limiting part 21 supports and blocks the lower end plate 3, so that the lower end plate 3 is installed in the mounting cavity 23, thereby increasing the firmness of the connection between the lower end plate 3 and the inner rubber ring 2.

[0092] (2) The lower end plate 3 and the inner rubber ring 2 can be concentric, which does not require much additional equipment investment, saving manufacturing costs. In addition, the inner rubber ring 2 fixes the lower end plate 3, and the lower end plate 3 can also be buffered under the condition of frequent vibration, making it less likely to pull the welding area between the lower end plate 3 and the explosion-proof sheet 1, thus ensuring the reliability of welding.

[0093] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0094] The above embodiments are only used to illustrate the technical solution of this utility model and not to limit it; although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of this utility model or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the technical solution claimed by this utility model.

Claims

1. A cylindrical battery cap assembly, characterized by, The application relates to an anti-explosion sheet (1) provided with a convex part (11) at the bottom of the anti-explosion sheet (1), wherein the convex part (11) defines a positioning cavity (12) with an opening arranged downwards; an inner rubber ring (2) is in contact with the side of the convex part (11) facing the positioning cavity (12); the inner rubber ring (2) defines an installation cavity (23) with an opening arranged downwards, and the inner peripheral wall of the installation cavity (23) is provided with a limiting part (21) protruding from the inner peripheral wall of the installation cavity (23); a gap (24) is formed between the limiting part (21) and the top wall of the installation cavity (23); a lower end plate (3) is arranged in the installation cavity (23), and the outer edge of the lower end plate (3) is arranged in the gap (24). The limiting part (21) is located at the opening of the installation cavity (23); the thickness of the peripheral wall at the middle of the installation cavity (23) is L1, the thickness between the side of the limiting part (21) facing the installation cavity (23) and the outer peripheral wall of the inner rubber ring (2) is L2, and the ratio of L1 to L2 is greater than or equal to 64% and less than or equal to 84%. The height of the convex part (11) is H1, the height of the inner rubber ring (2) is H2, and the ratio of H1 to H2 is greater than or equal to 52% and less than or equal to 72%. The height between the top of the limiting part (21) and the top wall of the installation cavity (23) is H3, and the ratio of H3 to the height H2 of the inner rubber ring (2) is greater than or equal to 21% and less than or equal to 41%.

2. The cylindrical battery cap assembly of claim 1, wherein, The outer edge of the lower end plate (3) is provided with an extension part (31), the thickness of the extension part (31) is smaller than the thickness of the outer edge of the lower end plate (3), the upper end of the extension part (31) is located at the outer edge of the lower end plate (3), and the extension part (31) is arranged in the gap (24); when the extension part (31) is arranged in the gap (24), the distance L3 between the limiting part (21) and the lower peripheral wall of the outer edge of the lower end plate (3) satisfies 0.1mm<=L3<=0.3mm; the distance S1 between the outer edge of the extension part (31) and the inner wall of the installation cavity (23) satisfies 0.03mm<=S1<=0.1mm.

3. The cylindrical battery cap assembly of claim 1, wherein, The top surface of the extension part (31) is flush with the top surface of the lower end plate (3); the ratio of the thickness H4 of the extension part (31) to the thickness H5 of the outer edge of the lower end plate (3) is greater than or equal to 40% and less than or equal to 60%.

4. The cylindrical battery cap assembly of any one of claims 1-3, wherein, The ratio of the height H2 of the inner rubber ring (2) to the thickness H6 of the top wall of the installation cavity (23) is greater than or equal to 200% and less than or equal to 240%.

5. The cylindrical battery cap assembly of any one of claims 1-3, wherein, The outer peripheral wall of the convex part (11) and the bottom surface of the anti-explosion sheet (1) define an included angle alpha, and the included angle alpha satisfies 95<=alpha<=125. ​ 6. The cylindrical battery cap assembly of claim 5, wherein, ​ 7. The cylindrical battery cap assembly of claim 6, wherein, ​ 8. The cylindrical battery cap assembly of claim 7, wherein, ​ 9. The cylindrical battery cap assembly of claim 6, wherein, The top wall of the mounting cavity (23) is provided with a first air passage hole (22) for air to pass through, the first air passage hole (22) is arranged in a vertical direction; the peripheral wall thickness of the mounting cavity (23) is L1, the distance between the peripheral wall of the inner rubber ring (2) and the hole wall of the first air passage hole (22) is L4, the ratio of L1 to L4 is greater than or equal to 23% and less than or equal to 33%.

10. A cylindrical secondary battery characterized by comprising: A cylindrical battery cap assembly comprising the cylindrical battery cap assembly of any one of claims 1-9.

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