Cap assembly and cylindrical secondary battery

Abstract

The utility model relates to and discloses a cap assembly and a cylindrical secondary battery. Relates to the technical field of new energy batteries. The explosion-proof device specifically comprises an outer insulating ring, an explosion-proof piece and a top cover plate, the top cover plate is arranged at the top of the explosion-proof piece, the inner side of the outer insulating ring abuts against the top cover plate and the side end of the explosion-proof piece at the same time, the bottom of the outer insulating ring is provided with a horizontally-extending limiting part, the top of the outer insulating ring is provided with a vertically-extending edge sealing part, and the top of the limiting part abuts against the bottom of the explosion-proof piece. The edge sealing part is bent and then abuts against the top of the top cover plate. According to the utility model, the ratio H1 / H0 of the height H1 of the edge sealing part to the overall height H0 of the outer insulating ring is set to be 45%-55%, so that not only is the height of the edge sealing part extending in the vertical direction prevented from being too large and the edge sealing part is prevented from interfering with the convex part on the top cover plate after being bent, but also the height of the edge sealing part extending in the vertical direction is prevented from being too small and the edge sealing part is prevented from interfering with the convex part on the top cover plate after being bent. And the covering area of the edge sealing part on the top cover plate after the edge sealing part is bent is ensured, so that the sealing performance and the safety performance of the cylindrical secondary battery are improved.

Description

Technical Field

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

[0002] Cylindrical secondary batteries are widely used in various fields, including mobile devices, electric vehicles, energy storage systems, and consumer electronics, due to their advantages such as high energy density, good heat dissipation, good mechanical strength, ease of manufacturing, and wide range of applications. The cap assembly, as a crucial component of cylindrical secondary batteries, plays a vital role in sealing, conductivity, and safety protection. Therefore, optimizing the cap assembly is particularly important in the design of cylindrical secondary batteries.

[0003] Existing cap assemblies for cylindrical secondary batteries typically include an outer insulating ring, an explosion-proof sheet, and a top cover plate. The top cover plate is located on top of the explosion-proof sheet, and the outer insulating ring is located outside the top cover plate and the explosion-proof sheet. During the assembly of the cap assembly, the portion of the outer insulating ring that extends beyond the height of the top cover plate is usually bent inward and then pressed onto the top of the top cover plate to ensure the sealing of the cap assembly.

[0004] If the portion of the outer insulating ring extending beyond the height of the top cover plate is designed to be too large, it will interfere with the protrusion on the top of the top cover plate used for welding with other cylindrical secondary batteries when it is bent inward and pressed onto the top cover plate. This will affect the sealing performance of the cap assembly, resulting in poor sealing of the cylindrical secondary batteries and a risk of leakage. Conversely, if the portion of the outer insulating ring extending beyond the height of the top cover plate is designed to be too small, it will cover too little area on the top of the top cover plate when it is bent inward and pressed onto the top cover plate. This will affect both the sealing performance and the structural strength of the cap assembly. Utility Model Content

[0005] The purpose of this invention is to address the shortcomings of the prior art by providing a cap assembly and a cylindrical secondary battery that can ensure both the sealing performance and structural strength of the cap assembly, thereby improving the sealing performance and safety of the cylindrical secondary battery.

[0006] This utility model proposes a cap assembly, including an outer insulating ring, an explosion-proof sheet, and a top cover plate. The top cover plate is disposed on top of the explosion-proof sheet, and the outer insulating ring is disposed on the outside of the top cover plate and the explosion-proof sheet. The inner side of the outer insulating ring abuts against the side ends of both the top cover plate and the explosion-proof sheet. The bottom of the outer insulating ring has a horizontally extending limiting part, and the top has a vertically extending sealing part. The top of the limiting part abuts against the bottom of the explosion-proof sheet, and the sealing part abuts against the top of the top cover plate after being bent. In the vertical direction, the ratio H1 of the height H1 of the sealing part to the overall height H0 of the outer insulating ring is 45% to 55%, and the overall height H0 of the outer insulating ring is in the range of 2mm to 4mm.

[0007] Furthermore, in the vertical direction, the ratio H2 of the sum of the heights of the top cover plate and the explosion-proof sheet to the overall height H0 of the outer insulating ring is 18% to 28%.

[0008] Furthermore, in the vertical direction, the ratio H21 / H22 of the height H21 of the top cover plate to the height H22 of the explosion-proof sheet is 95%-125%.

[0009] Furthermore, in the vertical direction, the ratio H3 of the height of the limiting part to the height H0 of the outer insulating ring as a whole is 20% to 32%.

[0010] Furthermore, the inner side of the outer insulating ring is provided with a first groove, which is located between the limiting part and the top limiting part, and the side ends of the top cover plate and the explosion-proof sheet are inserted into the first groove.

[0011] Furthermore, in the horizontal direction, the ratio W2 of the width of the outer insulating ring at the first groove to the width W1 of the outer insulating ring at the top limiting portion is 68% to 80%, and the width W1 of the outer insulating ring at the top limiting portion is in the range of 0.5mm to 0.7mm.

[0012] Furthermore, the top of the limiting part is provided with a second groove, and the second groove is filled with adhesive for fixing the explosion-proof sheet to the limiting part.

[0013] Furthermore, in the vertical direction, the ratio H4 of the height of the second groove to the height H3 of the limiting part, H4 / H3, is 12% to 22%; in the horizontal direction, the ratio W31 of the width of the second groove to the width W3 of the limiting part, W31 / W3, is 5% to 15%, and the width W3 of the limiting part ranges from 2mm to 4mm.

[0014] Furthermore, the two opposite sides of the second groove are inclined surfaces, and the angle A between the inclined surface and the horizontal plane is 30° to 60°.

[0015] This utility model also proposes a cylindrical secondary battery, including the aforementioned cap assembly.

[0016] The cap assembly and cylindrical secondary battery proposed in this utility model have the following beneficial effects:

[0017] (1) The ratio H1 / H0 of the height H1 of the sealing edge to the overall height H0 of the outer insulating ring is set to 45% to 55%. This prevents the sealing edge from extending too high in the vertical direction, which would cause interference with the protrusion on the top cover plate after bending. It also prevents the sealing edge from extending too low in the vertical direction, ensuring the coverage area of ​​the sealing edge on the top cover plate, thereby improving the sealing and safety performance of the cylindrical secondary battery.

[0018] (2) The height H0 of the outer insulating ring in this cap assembly is set between 2mm and 4mm. Therefore, when designing the dimensions of the outer insulating ring in the cap assembly, the value of H0 can be determined first, and then the value of H1 / H0 can be determined. Based on the value of H0 and the value of H1 / H0, the value of H1 can be obtained.

[0019] (3) The ratio H2 / H0 of the sum of the heights of the top cover plate and the explosion-proof sheet to the overall height H0 of the outer insulating ring is set between 18% and 28%. This prevents the sum of the heights of the top cover plate and the explosion-proof sheet from being too small, resulting in the thickness of the top cover plate and the explosion-proof sheet being too small. It also prevents the sum of the heights of the top cover plate and the explosion-proof sheet from being too large, resulting in the area covered by the sealing edge after bending being too small. This improves the sealing and safety performance of the cylindrical secondary battery.

[0020] (4) The ratio H21 / H22 of the height H21 of the top cover plate to the height H22 of the explosion-proof sheet is set between 95% and 125% in this cap assembly. This prevents the thickness of the top cover plate from being too large or too small, thereby reducing the processing cost of the cylindrical secondary battery and enhancing the structural strength of the cylindrical secondary battery. It also prevents the thickness of the explosion-proof sheet from being too large or too small, thereby improving the safety performance and service life of the cylindrical secondary battery.

[0021] (5) The ratio H3 / H0 of the height H3 of the limiting part to the overall height H0 of the outer insulating ring is set between 20% and 32% in this cap assembly, thereby preventing the height H3 of the limiting part from being too large or too small, ensuring the thickness of the limiting part and the height of the sealing part, and thus improving the sealing and safety performance of the cylindrical secondary battery.

[0022] (6) The ratio W2 / W1 of the width W2 of the outer insulating ring at the first groove to the width W1 of the outer insulating ring at the top limiting part is set between 68% and 80% in this cap assembly, thereby preventing the depth of the first groove from being too small or too large, thus ensuring the stability of the cap assembly structure, improving the safety performance of the cylindrical secondary battery, and increasing the production efficiency of the cylindrical secondary battery.

[0023] (7) The width W1 of the insulating ring at the top limit part of this cap assembly is set between 0.5mm and 0.7mm. Therefore, when designing the size of the outer insulating ring in the cap assembly, the value of W1 can be determined first, and then the value of W2 / W1 can be determined according to the range of W2 / W1. Thus, the value of W2 can be obtained according to the value of W1 and the value of W2 / W1, thereby completing the design of the size of the first groove.

[0024] (8) The ratio of the height H4 of the second groove to the height H3 of the limiting part, H4 / H3, is set between 12% and 22%, and the ratio of the width W31 of the second groove to the width W3 of the limiting part, W31 / W3, is set between 5% and 15%, to prevent the groove area of ​​the second groove on the limiting part from being too large or too small, thereby ensuring the stability of the cap assembly structure and improving the safety performance of the cylindrical secondary battery.

[0025] (9) The angle A between the inclined surfaces on both sides of the second groove and the horizontal plane is set between 30° and 60° to prevent the angle A from being too large or too small. This ensures the structural strength of the limiting part and makes it easier for the glue to overflow from the second groove, thereby ensuring the stability of the cap assembly structure and improving the safety performance of the cylindrical secondary battery. Attached Figure Description

[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. In these drawings, similar reference numerals are used to denote similar elements.

[0027] Figure 1 This is a schematic diagram of the structure of a cap assembly according to an embodiment of the present utility model;

[0028] Figure 2 This is a structural schematic diagram of the top cover plate and explosion-proof sheet of a cap assembly according to an embodiment of the present utility model;

[0029] Figure 3 This is a partial structural diagram of the outer insulating ring of a cap assembly according to an embodiment of the present invention.

[0030] In the diagram: 1. Outer insulating ring; 11. Limiting part; 111. Second groove; 12. Sealing part; 13. First groove; 2. Explosion-proof sheet; 3. Top cover plate. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. 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.

[0032] Please see Figures 1-3 An embodiment of the present invention provides a cap assembly comprising an outer insulating ring 1, an explosion-proof sheet 2, and a top cover plate 3. The top cover plate 3 is disposed on top of the explosion-proof sheet 2. The outer insulating ring 1 is disposed on the outer side of the top cover plate 3 and the explosion-proof sheet 2. The inner side of the outer insulating ring 1 simultaneously abuts against the side ends of the top cover plate 3 and the explosion-proof sheet 2. The bottom of the outer insulating ring 1 is provided with a horizontally extending limiting part 11, and the top is provided with a vertically extending sealing edge part 12. The top of the limiting part 11 abuts against the bottom of the explosion-proof sheet 2, and the sealing edge part 12 abuts against the top of the top cover plate 3 after being bent. In the vertical direction, the ratio H1 / H0 of the height H1 of the sealing edge part 12 to the overall height H0 of the outer insulating ring 1 is 45% to 55%, and the overall height H0 of the outer insulating ring 1 ranges from 2 mm to 4 mm.

[0033] In this application, the cap assembly includes an outer insulating ring 1, an explosion-proof sheet 2, and a top cover plate 3. The top cover plate 3 is disposed on top of the explosion-proof sheet 2 and is used to lead out the positive electrode of the cylindrical secondary battery. The outer insulating ring 1 is disposed on the outside of the explosion-proof sheet 2 and the top cover plate 3, and the inner side of the outer insulating ring 1 abuts against the side ends of the top cover plate 3 and the explosion-proof sheet 2, thereby fixing, sealing, and insulating the top cover plate 3 and the explosion-proof sheet 2 through the outer insulating ring 1.

[0034] The outer insulating ring 1 has a limiting part 11 at the bottom and a sealing part 12 at the top. The limiting part 11 extends horizontally and the sealing part 12 extends vertically, thus forming an L-shaped structure for the outer insulating ring 1. Since the inner side of the outer insulating ring 1 abuts against the side ends of both the top cover plate 3 and the explosion-proof sheet 2, in this application, the top cover plate 3 and the explosion-proof sheet 2 have the same cross-sectional diameter, so that when the top cover plate 3 is placed on top of the explosion-proof sheet 2, the side ends of the top cover plate 3 are aligned with the side ends of the explosion-proof sheet 2.

[0035] During the assembly of the cap assembly, the top cover plate 3 and the explosion-proof sheet 2 are positioned perpendicular to the sealing edge portion 12, i.e., the top cover plate 3 and the explosion-proof sheet 2 are positioned horizontally. At this time, the top surface of the limiting portion 11 extending horizontally abuts against the bottom surface of the explosion-proof sheet 2, limiting the bottom of the explosion-proof sheet 2. The inner surface of the outer insulating ring 1 extending vertically abuts against the side ends of the top cover plate 3 and the explosion-proof sheet 2, thereby limiting the side ends of the top cover plate 3 and the explosion-proof sheet 2. The sealing edge portion 12 extends vertically upward at the top of the top cover plate 3. By bending the sealing edge portion 12 inward, it is pressed against the top of the top cover plate 3, limiting the top of the top cover plate 3. This achieves the function of the outer insulating ring 1 in fixing, sealing, and insulating the top cover plate 3 and the explosion-proof sheet 2.

[0036] In actual use, if the ratio H1 / H0 of the height H1 of the sealing edge 12 to the overall height H0 of the outer insulating ring 1 is set too large in the vertical direction, that is, if the height of the sealing edge 12 extending in the vertical direction is designed to be too large, it will cause interference with the protrusion on the top of the top cover plate 3 used for welding with other cylindrical secondary batteries when it is bent inward and pressed onto the top cover plate 3. This will affect the sealing performance of the cap assembly, resulting in poor sealing performance of the cylindrical secondary battery and a risk of leakage.

[0037] If the ratio H1 / H0 of the height H1 of the sealing edge 12 to the overall height H0 of the outer insulating ring 1 is set too large, that is, the height of the sealing edge 12 extending in the vertical direction is designed too small, it will cause the area covered on the top of the top cover plate 3 to be too small when it is bent inward and pressed onto the top cover plate 3. This will affect both the sealing performance of the cap assembly and the structural strength of the cap assembly.

[0038] Therefore, in this application, in the vertical direction, the ratio H1 / H0 of the height H1 of the sealing edge 12 to the overall height H0 of the outer insulating ring 1 is set to 45% to 55%. This prevents the sealing edge 12 from extending too high in the vertical direction, which would cause interference with the protrusion on the top cover plate 3 after bending. It also prevents the sealing edge 12 from extending too low in the vertical direction, ensuring the coverage area of ​​the sealing edge 12 on the top cover plate 3 after bending. This ensures both the sealing performance and structural strength of the cap assembly, thereby improving the sealing performance and safety of the cylindrical secondary battery.

[0039] In this application, the overall height H0 of the outer insulating ring 1 is set between 2mm and 4mm. Therefore, when designing the dimensions of the outer insulating ring 1 in the cap assembly, the value of H0 can be determined first, and then the value of H1 / H0 can be determined. Based on the values ​​of H0 and H1 / H0, the value of H1 can be obtained. Preferably, in this application, the value of H0 can be set to 3.4mm, and the value of H1 / H0 can be set to 52%, resulting in a value of H1 of 1.77mm.

[0040] In this embodiment, in the vertical direction, the ratio H2 / H0 of the sum of the heights H2 of the top cover plate 3 and the explosion-proof sheet 2 to the overall height H0 of the outer insulating ring 1 is 18% to 28%. In actual use, if the ratio H2 / H0 of the sum of the heights H2 of the top cover plate 3 and the explosion-proof sheet 2 to the overall height H0 of the outer insulating ring 1 is set too small, that is, if the sum of the heights H2 of the top cover plate 3 and the explosion-proof sheet 2 is designed to be too small...

[0041] Since the vertical height of the top cover plate 3 and the explosion-proof sheet 2 is equal to the thickness of the top cover plate 3 and the explosion-proof sheet 2, designing the thickness of the top cover plate 3 and the explosion-proof sheet 2 to be too small will result in poor structural strength of the top cover plate 3 and the explosion-proof sheet 2, making them prone to deformation. It will also affect the stability of the valve opening pressure of the explosion-proof sheet 2, thus affecting both the structural strength and the safety performance of the cylindrical secondary battery.

[0042] If the ratio H2 / H0 of the sum of the heights H2 of the top cover plate 3 and the explosion-proof sheet 2 to the overall height H0 of the outer insulating ring 1 is set too large, that is, if the sum of the heights H2 of the top cover plate 3 and the explosion-proof sheet 2 is designed to be too large, the area covered on the top of the top cover plate 3 when the sealing edge part 12 is bent and pressed onto the top of the top cover plate 3 will be too small. This will affect both the sealing performance and the structural strength of the cap assembly, and thus affect both the sealing performance and the structural strength of the cylindrical secondary battery.

[0043] Therefore, in this application, in the vertical direction, the ratio H2 / H0 of the sum of the heights H2 of the top cover plate 3 and the explosion-proof sheet 2 to the overall height H0 of the outer insulating ring 1 is set between 18% and 28%. This prevents the sum of the heights H2 of the top cover plate 3 and the explosion-proof sheet 2 from being too small, resulting in insufficient thickness of the top cover plate 3 and the explosion-proof sheet 2, and also prevents the sum of the heights H2 of the top cover plate 3 and the explosion-proof sheet 2 from being too large, resulting in insufficient coverage area on the top of the top cover plate 3 after the sealing edge 12 is bent. This ensures both the sealing performance and structural strength of the cap assembly, thereby improving the sealing performance and safety of the cylindrical secondary battery.

[0044] As mentioned in the previous embodiments, when designing the dimensions of the outer insulating ring 1 in the cap assembly, the value of H0 can be determined first. Preferably, the value of H0 can be set to 3.4 mm. Therefore, in this embodiment, the value of H2 / H0 can be determined based on the range of H2 / H0, and then the value of H2 can be obtained based on the determined value of H0 and the value of H2 / H0. Preferably, in this application, the value of H2 / H0 can be set to 22%, that is, the value of H2 is 0.75 mm.

[0045] Furthermore, in this embodiment, in the vertical direction, the ratio H21 / H22 of the height H21 of the top cover plate 3 to the height H22 of the explosion-proof plate 2 is 95%-125%. In the previous embodiment, the value of the sum of the heights H2 of the top cover plate 3 and the explosion-proof plate 2 was obtained. In actual use, if the ratio H21 / H22 of the height H21 of the top cover plate 3 to the height H22 of the explosion-proof plate 2 is set too large, that is, the height H21 of the top cover plate 3 is too large and the height H22 of the explosion-proof plate 2 is too small, the problem will be exacerbated by the lack of a proper balance between the height of the top cover plate 3 and the height of the explosion-proof plate 2.

[0046] Since the vertical height of the top cover plate 3 and the explosion-proof sheet 2 is equal to their respective thicknesses, designing the top cover plate 3 to be too thick would result in a protrusion being stretched on it, making welding with other cylindrical secondary batteries more difficult and increasing the processing cost of the cylindrical secondary batteries. Conversely, designing the explosion-proof sheet 2 to be too thin would affect its structural strength, thereby reducing its opening pressure and causing it to open prematurely in the event of thermal runaway, thus impacting the lifespan of the cylindrical secondary batteries.

[0047] If the ratio H21 / H22 of the height H21 of the top cover plate 3 to the height H22 of the explosion-proof sheet 2 is set too small, that is, the height H21 of the top cover plate 3 is too small and the height H22 of the explosion-proof sheet 2 is too large, that is, the thickness of the top cover plate 3 is designed to be too small and the thickness of the explosion-proof sheet 2 is designed to be too large.

[0048] If the thickness of the top cover plate 3 is too small, its structure will deteriorate. This will cause the protrusions on the top cover plate 3 to deform or collapse during welding, leading to problems such as incomplete welds and explosions, increasing the welding defect rate and the production cost of the cylindrical secondary battery. If the thickness of the explosion-proof plate 2 is too large, it will increase the valve opening pressure of the explosion-proof plate 2, causing a delay in the valve opening in the event of thermal runaway, thus affecting the safety performance of the cylindrical secondary battery.

[0049] Therefore, in this application, in the vertical direction, the ratio H21 / H22 of the height H21 of the top cover plate 3 to the height H22 of the explosion-proof sheet 2 is set between 95% and 125%. This prevents the thickness of the top cover plate 3 from being too large or too small, thereby reducing the processing cost of the cylindrical secondary battery and enhancing the structural strength of the cylindrical secondary battery. It also prevents the thickness of the explosion-proof sheet 2 from being too large or too small, thereby improving the safety performance and service life of the cylindrical secondary battery.

[0050] In the preceding embodiments, the sum of the heights H2 of the top cover plate 3 and the explosion-proof sheet 2 has been determined, i.e., the value of H21 + H22 has been determined. Therefore, in this embodiment, the value of H21 / H22 is determined based on the range of the ratio H21 / H22, thereby obtaining the values ​​of H21 and H22 based on the values ​​of H21 + H22 and H21 / H22. Preferably, in this application, the value of H21 / H22 can be set to 114%, i.e., the value of H21 is 0.4 mm and the value of H22 is 0.35 mm.

[0051] In this embodiment, the ratio H3 / H0 of the height H3 of the limiting part 11 in the vertical direction to the overall height H0 of the outer insulating ring 1 is 20% to 32%. In this application, when the outer insulating ring 1 is located outside the top cover plate 3 and the explosion-proof sheet 2, the top surface of the limiting part 11 extending in the horizontal direction abuts against the bottom surface of the explosion-proof sheet 2. After the cap assembly is installed into the battery housing, it is usually necessary to fold the sealing edge of the battery housing inward and press it onto the cap assembly to complete the sealing of the battery housing.

[0052] During this process, the sealing edge of the battery casing bends the sealing edge 12 of the outer insulating ring 1 inward, pressing the sealing edge 12 of the outer insulating ring 1 against the top of the top cover plate 3. As the sealing edge of the battery casing presses the sealing edge 12 of the outer insulating ring 1 against the top of the top cover plate 3, force is transmitted through the top cover plate 3 and the explosion-proof sheet 2, causing compression on the limiting part 11 at the bottom of the outer insulating ring 1. This compression ensures the pressure resistance of the battery casing seal.

[0053] In practical use, if the ratio H3 / H0 of the height H3 of the limiting part 11 to the overall height H0 of the outer insulating ring 1 is set too small in the vertical direction, that is, if the height H3 of the limiting part 11 is designed too small, the height of the limiting part 11 in the vertical direction is equal to the thickness of the limiting part 11. If the thickness of the limiting part 11 is designed too small, when the battery casing is sealed, the limiting part 11 will not have enough thickness to compress it, resulting in poor airtightness of the battery casing and unstable sealing pressure resistance, thus affecting the safety performance of the cylindrical secondary battery.

[0054] If the ratio H3 / H0 of the height H3 of the limiting part 11 to the overall height H0 of the outer insulating ring 1 is set too large, that is, the height of the limiting part 11 accounts for a large proportion of the overall height of the outer insulating ring 1, the height of the sealing part 12 will decrease in proportion to the overall height of the outer insulating ring 1. As a result, the height of the sealing part 12 will be insufficient, and when it is bent inward and pressed onto the top cover plate 3, the area covered on the top of the top cover plate 3 will be too small. This will affect both the sealing performance and the structural strength of the cap assembly.

[0055] Therefore, in this application, in the vertical direction, the ratio H3 / H0 of the height H3 of the limiting part 11 to the overall height H0 of the outer insulating ring 1 is set between 20% and 32%, thereby preventing the height H3 of the limiting part 11 from being too large or too small, ensuring the thickness of the limiting part 11 and the height of the sealing part 12, and thus improving the sealing and safety performance of the cylindrical secondary battery.

[0056] As mentioned in the previous embodiments, when designing the dimensions of the outer insulating ring 1 in the cap assembly, the value of H0 can be determined first. Preferably, the value of H0 can be set to 3.4 mm. Therefore, in this embodiment, the value of H3 / H0 can be determined based on the range of H3 / H0, and then the value of H3 can be obtained based on the determined value of H0 and the value of H3 / H0. Preferably, in this application, the value of H3 / H0 can be set to 26%, that is, the value of H3 is 0.88 mm.

[0057] In this application, the inner side of the outer insulating ring 1 simultaneously abuts against the side ends of both the top cover plate 3 and the explosion-proof sheet 2. Therefore, in this embodiment, a first groove 13 is provided on the inner side of the outer insulating ring 1, and the first groove 13 is disposed between the limiting part 11 and the top limiting part 11. When the top cover plate 3 and the explosion-proof sheet 2 are installed on the inner side of the outer insulating ring 1, the side ends of the top cover plate 3 and the explosion-proof sheet 2 are inserted into the first groove 13, thereby limiting the side ends of the top cover plate 3 and the explosion-proof sheet 2 through the first groove 13, so that the outer insulating ring 1 can better fix the top cover plate 3 and the explosion-proof sheet 2, thereby improving the sealing and safety performance of the cylindrical secondary battery.

[0058] Further, in this embodiment, in the horizontal direction, the ratio W2 of the width W2 of the outer insulating ring 1 at the first groove 13 to the width W1 of the outer insulating ring 1 at the top limiting portion 11 is 68% to 80%, and the width W1 of the outer insulating ring 1 at the top limiting portion 11 ranges from 0.5mm to 0.7mm. Since in this application, when the top cover plate 3 and the explosion-proof sheet 2 are installed inside the outer insulating ring 1, the side ends of the top cover plate 3 and the explosion-proof sheet 2 are inserted into the first groove 13, in order to ensure the limiting effect of the first groove 13 on the top cover plate 3 and the explosion-proof sheet 2, in the vertical direction, the sum of the heights H2 of the top cover plate 3 and the explosion-proof sheet 2 is equal to the height of the first groove 13.

[0059] Since the difference between the width W2 of the outer insulating ring 1 at the first groove 13 and the width W1 of the outer insulating ring 1 at the top limiting part 11 is equal to the depth of the first groove 13, in actual use, if the ratio W2 / W1 of the width W2 of the outer insulating ring 1 at the first groove 13 and the width W1 of the outer insulating ring 1 at the top limiting part 11 is set too large in the horizontal direction, that is, if the depth of the first groove 13 is designed too small, the limiting effect of the first groove 13 on the top cover plate 3 and the explosion-proof sheet 2 will be reduced, thereby affecting the stability of the cap assembly structure.

[0060] If the ratio W2 / W1 of the width W2 of the outer insulating ring 1 at the first groove 13 to the width W1 of the outer insulating ring 1 at the top limiting part 11 is set too small, that is, the depth of the first groove 13 is designed to be too large, it will be difficult to insert the side ends of the top cover plate 3 and the explosion-proof sheet 2 into the first groove 13 when the top cover plate 3 and the explosion-proof sheet 2 are installed inside the outer insulating ring 1, thereby reducing production efficiency.

[0061] Therefore, in this application, in the horizontal direction, the ratio W2 / W1 of the width W2 of the outer insulating ring 1 at the first groove 13 to the width W1 of the outer insulating ring 1 at the top limiting part 11 is set between 68% and 80%, thereby preventing the depth of the first groove 13 from being too small or too large, thus ensuring the stability of the cap assembly structure, improving the safety performance of the cylindrical secondary battery, and increasing the production efficiency of the cylindrical secondary battery.

[0062] In this embodiment, the width W1 of the insulating ring at the top limiting portion 11 is set between 0.5mm and 0.7mm. Therefore, when designing the dimensions of the outer insulating ring 1 in the cap assembly, the value of W1 can be determined first, and then the value of W2 / W1 can be determined according to the range of W2 / W1. Thus, based on the value of W1 and the value of W2 / W1, the value of W2 can be obtained, thereby completing the design of the dimensions of the first groove 13. Preferably, in this application, the value of W1 can be set to 0.56mm, and the value of W2 / W1 can be set to 73%, that is, the value of W2 is 0.41mm.

[0063] In this embodiment, the top of the limiting part 11 is provided with a second groove 111, and the second groove 111 is filled with adhesive for fixing the explosion-proof sheet 2 to the limiting part 11. As mentioned in the previous embodiments, the top of the limiting part 11 abuts against the bottom of the explosion-proof sheet 2, and the limiting part 11 will be squeezed during the sealing process of the battery casing. Therefore, in this application, the top of the limiting part 11 is provided with a second groove 111, and adhesive is injected into the second groove 111.

[0064] When the battery casing is sealed and the limiting part 11 is squeezed, the glue in the second groove 111 overflows, bonding the top of the limiting part 11 to the bottom of the explosion-proof sheet 2, thereby improving the stability of the cap assembly structure and thus improving the safety performance of the cylindrical secondary battery.

[0065] Furthermore, in this embodiment, in the vertical direction, the ratio H4 of the height H4 of the second groove 111 to the height H3 of the limiting part 11 is 12% to 22%; in the horizontal direction, the ratio W31 of the width W31 of the second groove 111 to the width W3 of the limiting part 11 is 5% to 15%, and the width W3 of the limiting part 11 is in the range of 2mm to 4mm.

[0066] It is foreseeable that the groove area of ​​the second groove 111 in the limiting part 11 will affect the structural strength of the limiting part 11. If the groove area of ​​the second groove 111 is too large, it will reduce the structural strength of the limiting part 11, thereby reducing the stability of the cap assembly structure; if the groove area of ​​the second groove 111 is too small, it will result in less glue filling the second groove 111, affecting the adhesion effect of the glue to the top of the limiting part 11 and the bottom of the explosion-proof sheet 2.

[0067] In actual use, if the ratio H4 / H3 of the height H4 of the second groove 111 to the height H3 of the limiting part 11 is set too large in the vertical direction, and the ratio W31 / W3 of the width W31 of the second groove 111 to the width W3 of the limiting part 11 is set too large in the horizontal direction, the slotted area of ​​the second groove 111 will be too large, thereby affecting the structural strength of the limiting part 11.

[0068] If the ratio H4 / H3 of the height H4 of the second groove 111 to the height H3 of the limiting part 11 is set too small in the vertical direction, and the ratio W31 / W3 of the width W31 of the second groove 111 to the width W3 of the limiting part 11 is set too small in the horizontal direction, the groove area of ​​the second groove 111 will be too small, thereby affecting the bonding effect of the adhesive to the top of the limiting part 11 and the bottom of the explosion-proof sheet 2.

[0069] Therefore, in this application, in the vertical direction, the ratio H4 / H3 of the height H4 of the second groove 111 to the height H3 of the limiting part 11 is set between 12% and 22%, and in the horizontal direction, the ratio W31 / W3 of the width W31 of the second groove 111 to the width W3 of the limiting part 11 is set between 5% and 15%. This prevents the groove area of ​​the second groove 111 on the limiting part 11 from being too large or too small, thereby ensuring both the structural strength of the limiting part 11 and the bonding effect of the adhesive filled in the second groove 111 on the limiting part 11 and the explosion-proof sheet 2, thus ensuring the stability of the cap assembly structure and improving the safety performance of the cylindrical secondary battery.

[0070] In the previous embodiments, the value of the height H3 of the limiting part 11 has been determined. Therefore, in this embodiment, the value of H4 / H3 can be determined according to the range of H4 / H3, and the value of H4 can be obtained based on the value of H3 and the value of H4 / H3. Preferably, in this application, the value of H4 / H3 can be set to 17%, that is, the value of H4 is 0.15mm.

[0071] In this embodiment, the width W3 of the limiting part 11 is set between 2mm and 4mm. Therefore, in specific implementation, the value of W3 can be determined first, and then the value of W31 / W3 can be determined according to the range of W31 / W3. Thus, the value of W31 can be obtained based on the value of W3 and the value of W31 / W3. Preferably, in this application, the value of W3 can be set to 3mm, and the value of W31 / W3 can be set to 10%, that is, the value of W31 is 0.3mm.

[0072] As mentioned in the previous embodiment, when the battery casing is sealed and the limiting part 11 is squeezed, the glue in the second groove 111 overflows and bonds the top of the limiting part 11 to the bottom of the explosion-proof sheet 2. Therefore, in this application, the sides of the second groove 111 on opposite sides are set as inclined surfaces, so that when the limiting part 11 is squeezed, the glue filled in the second groove 111 is more likely to overflow and bond the limiting part 11 to the explosion-proof sheet 2, thereby improving the stability of the cap assembly structure and thus improving the safety performance of the cylindrical secondary battery.

[0073] In practical use, if the angle A between the inclined surfaces on both sides of the second groove 111 and the horizontal plane is too small, the opening range at the top of the second groove 111 will be too large, thereby affecting the structural strength of the limiting part 11 and thus affecting the stability of the cap assembly structure. If the angle A between the inclined surfaces on both sides of the second groove 111 and the horizontal plane is too large, it will be more difficult for the glue to overflow from the second groove 111, thereby affecting the bonding effect of the glue on the limiting part 11 and the explosion-proof sheet 2.

[0074] Therefore, in this application, the included angle A between the inclined surfaces on both sides of the second groove 111 and the horizontal plane is set between 30° and 60° to prevent the included angle A from being too large or too small. This ensures both the structural strength of the limiting part 11 and makes it easier for the adhesive to overflow from the second groove 111, thereby ensuring the stability of the cap assembly structure and improving the safety performance of the cylindrical secondary battery. Preferably, in this application, the included angle A is set to 45°.

[0075] In this embodiment of the invention, a cylindrical secondary battery is also provided, including the cap assembly described above.

[0076] The above-described contents can be implemented individually or in combination in various ways, and all such variations are within the protection scope of this utility model.

[0077] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A cap assembly, comprising an outer insulating ring (1), an explosion-proof sheet (2), and a top cover plate (3), wherein the top cover plate (3) is disposed on top of the explosion-proof sheet (2), and the outer insulating ring (1) is disposed on the outer side of the top cover plate (3) and the explosion-proof sheet (2), characterized in that: The inner side of the outer insulating ring (1) abuts against the side ends of the top cover plate (3) and the explosion-proof sheet (2). The bottom of the outer insulating ring (1) is provided with a horizontally extending limiting part (11) and the top is provided with a vertically extending sealing part (12). The top of the limiting part (11) abuts against the bottom of the explosion-proof sheet (2). The sealing part (12) abuts against the top of the top cover plate (3) after being bent. In the vertical direction, the ratio H1 of the height of the sealing part (12) to the height H0 of the outer insulating ring (1) is 45% to 55%. The range of the height H0 of the outer insulating ring (1) is 2mm to 4mm.

2. A cap assembly as described in claim 1, characterized in that: In the vertical direction, the ratio H2 of the sum of the heights of the top cover plate (3) and the explosion-proof sheet (2) to the overall height H0 of the outer insulating ring (1) is 18% to 28%.

3. A cap assembly as described in claim 2, characterized in that: In the vertical direction, the ratio H21 of the height H21 of the top cover plate (3) to the height H22 of the explosion-proof sheet (2) is 95%-125%.

4. A cap assembly as described in claim 1, characterized in that: In the vertical direction, the ratio H3 of the height of the limiting part (11) to the height H0 of the outer insulating ring (1) as a whole is 20% to 32%.

5. A cap assembly as described in claim 1, characterized in that: The inner side of the outer insulating ring (1) is provided with a first groove (13), which is located between the limiting part (11) and the sealing part (12). The side ends of the top cover plate (3) and the explosion-proof sheet (2) are inserted into the first groove (13).

6. A cap assembly as described in claim 5, characterized in that: In the horizontal direction, the ratio W2 of the width of the outer insulating ring (1) at the first groove (13) to the width W1 of the outer insulating ring (1) at the sealing portion (12) is 68% to 80%, and the width W1 of the outer insulating ring (1) at the sealing portion (12) is in the range of 0.5mm to 0.7mm.

7. A cap assembly as described in claim 1, characterized in that: The top of the limiting part (11) is provided with a second groove (111), and the second groove (111) is filled with glue for fixing the explosion-proof sheet (2) to the limiting part (11).

8. A cap assembly as described in claim 7, characterized in that: In the vertical direction, the ratio H4 of the height of the second groove (111) to the height H3 of the limiting part (11) is 12% to 22%; in the horizontal direction, the ratio W31 of the width of the second groove (111) to the width W3 of the limiting part (11) is 5% to 15%, and the width W3 of the limiting part (11) is in the range of 2mm to 4mm.

9. A cap assembly as described in claim 7, characterized in that: The two opposite sides of the second groove (111) are inclined surfaces, and the angle A between the inclined surface and the horizontal plane is 30° to 60°.

10. A cylindrical secondary battery, characterized in that, Includes the cap assembly as described in any one of claims 1-9.

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