A cylindrical lithium-ion battery

Abstract

This utility model discloses a cylindrical lithium-ion battery, belonging to the field of new energy battery technology. Specifically, it includes a top cover, an explosion-proof sheet, an outer insulating ring, and a housing. The housing is bent outside the outer insulating ring to form a top flange and a bottom flange. The top flange is pressed against the top of the outer insulating ring, and the bottom flange is pressed against the bottom of the outer insulating ring. The ratio H1 of the minimum height H1 of the outer insulating ring at the top flange pressing point to the radius R1 of the cylindrical lithium-ion battery is 3% to 4%. This utility model sets the ratio H1 / R1 of the minimum height H1 of the outer insulating ring at the top flange pressing point to the radius R1 of the cylindrical lithium-ion battery between 3% and 4% to prevent the minimum height H1 of the outer insulating ring at the top flange pressing point from being too large or too small, thereby preventing the compression of the top flange against the top of the outer insulating ring from being too large or too small, ensuring the sealing of the cylindrical lithium-ion battery, and thus ensuring the performance of the cylindrical lithium-ion battery.

Description

Technical Field

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

[0002] Cylindrical lithium-ion batteries typically consist of a casing, a core, and a cap assembly. The core is housed within the casing, and the cap assembly is connected to the casing, leading out the positive electrode of the core, while the negative electrode is led out from the casing, thus enabling the charging and discharging function of the cylindrical lithium-ion battery. The cap assembly typically includes a top cover, an explosion-proof diaphragm, and an outer insulating ring. The outer insulating ring is located outside the top cover and the explosion-proof diaphragm, used to isolate them from the casing.

[0003] To ensure the sealing of cylindrical lithium-ion batteries, when the cap assembly is connected to the casing, the casing is typically bent outside the outer insulating ring to form a top flange and a bottom flange. The top flange is pressed against the top of the outer insulating ring, and the bottom flange is pressed against the bottom of the outer insulating ring. In existing cylindrical lithium-ion batteries, the compression amount at the top of the outer insulating ring when the top flange of the casing is pressed against the top of the outer insulating ring is poorly designed.

[0004] Some cylindrical lithium-ion batteries have an excessively large compression amount at the top of the outer insulating ring due to the flange. Since the outer insulating ring is made of plastic, excessive compression can easily cause plastic deformation and permanent failure of the outer insulating ring, resulting in poor battery sealing and leakage, thus affecting the performance of the cylindrical lithium-ion battery. Conversely, some cylindrical lithium-ion batteries have an insufficiently small compression amount at the top of the outer insulating ring due to the flange, which can also lead to poor battery sealing and leakage, affecting the performance of the cylindrical lithium-ion battery. Utility Model Content

[0005] The purpose of this invention is to address the shortcomings of the prior art by providing a cylindrical lithium-ion battery that prevents both excessive compression of the top edge of the outer insulating ring and insufficient compression of the top edge of the outer insulating ring, thereby ensuring the sealing performance of the cylindrical lithium-ion battery and thus its performance.

[0006] This utility model proposes a cylindrical lithium-ion battery, including an upper cover plate, an explosion-proof sheet, an outer insulating ring, and a housing. The explosion-proof sheet is located at the bottom of the upper cover plate, and the outer insulating ring is located on the outer periphery of the upper cover plate and the explosion-proof sheet to insulate the upper cover plate and the explosion-proof sheet from the housing. The housing is bent outside the outer insulating ring to form a top flange and a bottom flange. The top flange is pressed against the top of the outer insulating ring, and the bottom flange is pressed against the bottom of the outer insulating ring. The minimum height H1 of the outer insulating ring at the top flange pressing point is 3% to 4% of the radius R1 of the cylindrical lithium-ion battery, with the ratio H1 / R1 being 3% to 4%.

[0007] Furthermore, the outer insulating ring includes a side extension extending vertically on the outer side of the upper cover plate and the explosion-proof sheet, and the ratio H1 of the minimum height H1 of the outer insulating ring at the top flange crimp to the width L1 of the side extension is 45.6% to 60.3%.

[0008] Furthermore, the outer insulating ring also includes an upper extension that extends laterally on the upper surface of the upper cover plate. The top flange is pressed against the upper extension and an upturned portion is formed at the end of the upper extension. The ratio of the maximum height H2 of the upturned portion from the upper cover plate to the radius R1 of the cylindrical lithium-ion battery, H2 / R1, is 5% to 7%.

[0009] Furthermore, the outer insulating ring also includes a lower extension extending laterally on the lower surface of the explosion-proof sheet, the bottom flange being pressed against the lower extension, and the ratio H3 of the minimum height of the lower extension at the bottom flange pressing point to the radius R1 of the cylindrical lithium-ion battery, H3 / R1, is 2.4% to 3.9%.

[0010] Furthermore, the angle A formed by the upturned portion and the upper cover plate in the horizontal direction is 27° to 47°.

[0011] Furthermore, when the bottom flange is pressed onto the lower extension, a recessed portion is formed at the end of the lower extension, and the angle B formed between the recessed portion and the explosion-proof sheet in the horizontal direction is 8° to 28°.

[0012] Furthermore, the ratio of the maximum length L2 of the upper extension to the radius R1 of the cylindrical lithium-ion battery, L2 / R1, is 21% to 30.5%.

[0013] Furthermore, the ratio of the maximum length L3 of the lower extension to the radius R1 of the cylindrical lithium-ion battery, L3 / R1, is 21% to 30.5%.

[0014] Furthermore, the width L1 of the side extension is 0.6mm to 0.76mm.

[0015] Furthermore, the radius R1 of the cylindrical lithium-ion battery is 9.5 mm to 11.5 mm.

[0016] The cylindrical lithium-ion battery proposed in this utility model has the following beneficial effects:

[0017] (1) The minimum height H1 of the outer insulating ring at the top flange crimping point is set between 3% and 4% of the radius R1 of the cylindrical lithium-ion battery to prevent the minimum height H1 of the outer insulating ring at the top flange crimping point from being too large or too small, thereby preventing the compression of the top flange on the top of the outer insulating ring from being too large or too small, ensuring the sealing of the cylindrical lithium-ion battery, and thus ensuring the performance of the cylindrical lithium-ion battery.

[0018] (2) The ratio of the minimum height H1 of the outer insulating ring at the top flange crimping point to the width L1 of the side extension is set to 45.6% to 60.3% in this cylindrical lithium-ion battery. This further prevents the compression of the top flange on the top of the outer insulating ring from being too large or too small, ensuring the sealing of the cylindrical lithium-ion battery and thus ensuring the performance of the cylindrical lithium-ion battery.

[0019] (3) The ratio of the maximum height H2 of the upturned part from the top cover plate to the radius R1 of the cylindrical lithium-ion battery is set to 5% to 7%, thereby further preventing the compression of the top edge of the external insulation ring from being too large or too small, ensuring the sealing of the cylindrical lithium-ion battery, and thus ensuring the performance of the cylindrical lithium-ion battery.

[0020] (4) The angle A formed by the upturned part and the top cover plate in the horizontal direction of this cylindrical lithium-ion battery is set to 27°~47°. By setting the angle A formed by the upturned part and the top cover plate in the horizontal direction within a suitable range, the maximum height H2 of the upturned part from the top cover plate can more accurately reflect the compression amount of the upper extension, thereby further preventing the compression amount of the top flange on the top of the external insulation ring from being too large or too small, ensuring the sealing of the cylindrical lithium-ion battery, and thus ensuring the performance of the cylindrical lithium-ion battery.

[0021] (5) The minimum height H3 of the lower extension at the bottom flange crimping point of this cylindrical lithium-ion battery is set to the ratio H3 / R1 of the radius R1 of the cylindrical lithium-ion battery between 2.4% and 3.9% to prevent the minimum height H1 of the outer insulating ring at the bottom flange crimping point from being too large or too small, thereby preventing the compression of the bottom flange of the outer insulating ring from being too large or too small, ensuring the sealing of the cylindrical lithium-ion battery, and thus ensuring the performance of the cylindrical lithium-ion battery.

[0022] (6) The cylindrical lithium-ion battery sets the angle B between the sinking part and the explosion-proof sheet in the horizontal direction between 8° and 28°, thereby further preventing the compression of the bottom edge of the outer insulation ring from being too large or too small, ensuring the sealing of the cylindrical lithium-ion battery, and thus ensuring the performance of the cylindrical lithium-ion battery.

[0023] (7) The ratio of the maximum length L2 of the upper extension to the radius R1 of the cylindrical lithium-ion battery is set to 21% to 30.5% to prevent the maximum length L2 of the upper extension from being too large or too small. This prevents interference between the upper extension and the protrusion of the upper cover plate, ensuring the assembly of the cylindrical lithium-ion battery, and also ensuring the insulation effect of the upper extension and the sealing of the battery, thereby ensuring the performance of the cylindrical lithium-ion battery.

[0024] (8) The ratio of the maximum length L3 of the lower extension to the radius R1 of the cylindrical lithium-ion battery, L3 / R1, is set to 17.1% to 26.7% to prevent the maximum length L3 of the lower extension from being too large or too small. This prevents the lower extension from interfering with the core, ensures the insulation effect of the outer insulating ring and the sealing of the battery, and thus ensures the performance of the cylindrical lithium-ion battery. Attached Figure Description

[0025] 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.

[0026] Figure 1 for Figure 2 Enlarged view of point A in the middle;

[0027] Figure 2 This is a partial structural schematic diagram of a cylindrical lithium-ion battery according to an embodiment of the present invention.

[0028] In the diagram: 1. Top cover plate; 2. Explosion-proof sheet; 3. Outer insulating ring; 31. Side extension; 32. Upper extension; 321. Upward curve; 33. Lower extension; 331. Downward curve; 4. Shell; 41. Top flange; 42. Bottom flange. Detailed Implementation

[0029] 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.

[0030] Please see Figure 1and Figure 2 A cylindrical lithium-ion battery according to an embodiment of the present invention includes an upper cover plate 1, an explosion-proof sheet 2, an outer insulating ring 3, and a housing 4. The upper cover plate 1, the explosion-proof sheet 2, and the outer insulating ring 3 are components of a cap assembly, which is connected to the housing 4 to seal the housing 4. The cap assembly leads out the positive electrode of the winding core loaded in the housing 4, and the housing 4 leads out the negative electrode of the winding core, thereby realizing the charging and discharging function of the cylindrical lithium-ion battery.

[0031] Specifically, the explosion-proof sheet 2 is located at the bottom of the upper cover plate 1 to provide explosion-proof protection for the battery; the protrusion of the upper cover plate 1 is used to weld with other cylindrical lithium-ion batteries during the battery assembly process; the outer insulating ring 3 is located on the outside of the upper cover plate 1 and the explosion-proof sheet 2. When the cap assembly is connected to the housing 4, the outer insulating ring 3 isolates the upper cover plate 1 and the explosion-proof sheet 2 from the inner wall of the housing 4, thereby achieving insulation between the cap assembly and the housing 4.

[0032] To ensure the sealing of the cylindrical lithium-ion battery, when the cap assembly is connected to the housing 4, the housing 4 is usually bent on the outside of the outer insulating ring 3 to form a top flange 41 and a bottom flange 42. The top flange 41 is pressed against the top of the outer insulating ring 3, and the bottom flange 42 is pressed against the bottom of the outer insulating ring 3.

[0033] If the top flange 41 is pressed against the top of the outer insulating ring 3, and the compression of the top of the outer insulating ring 3 is too large, it can easily cause plastic deformation of the outer insulating ring 3, resulting in permanent failure. This can lead to poor battery sealing, battery leakage, and affect the performance of the cylindrical lithium-ion battery. On the other hand, if the compression of the top flange 41 against the top of the outer insulating ring 3 is too small, the outer insulating ring 3 will not be able to achieve the proper sealing effect, resulting in poor battery sealing and battery leakage, which will also affect the performance of the cylindrical lithium-ion battery.

[0034] Therefore, in this application, when the top flange 41 is pressed against the top of the outer insulating ring 3, the minimum height of the outer insulating ring 3 at the pressing point of the top flange 41 is set to H1, and the radius of the cylindrical lithium-ion battery is set to R1. The ratio H1 / R1 of the minimum height H1 of the outer insulating ring 3 at the pressing point of the top flange 41 to the radius R1 of the cylindrical lithium-ion battery is set between 3% and 4% to prevent the minimum height H1 of the outer insulating ring 3 at the pressing point of the top flange 41 from being too large or too small. This prevents the compression of the top flange 41 on the top of the outer insulating ring 3 from being too large or too small, ensuring the sealing performance of the cylindrical lithium-ion battery and thus guaranteeing its performance.

[0035] In practical implementation, preferably, the ratio H1 / R1 of the minimum height H1 of the outer insulating ring 3 at the top flange 41 crimping point to the radius R1 of the cylindrical lithium-ion battery is set to 3.4%.

[0036] In this embodiment, the outer insulating ring 3 includes a side extension 31, which extends vertically on the outer surfaces of the upper cover plate 1 and the explosion-proof sheet 2. When the cap assembly is connected to the housing 4, the side extension 31 is located between the outer surfaces of the upper cover plate 1 and the explosion-proof sheet 2 and the inner wall of the housing 4, thus isolating the outer surfaces of the upper cover plate 1 and the explosion-proof sheet 2 from the inner wall of the housing 4.

[0037] In this application, the width of the side extension 31 is set to L1. Since the housing 4 does not compress the side extension 31 when the cap assembly is connected to the housing 4, the width L1 of the side extension 31 is the original thickness of the outer insulating ring 3, and the minimum height H1 of the outer insulating ring 3 at the top flange 41 is the minimum thickness of the top of the outer insulating ring 3 after being compressed by the top flange 41.

[0038] In actual use, if the ratio H1 / L1 of the minimum height H1 of the outer insulating ring 3 at the top flange 41 pressing point to the width L1 of the side extension 31 is set too small, that is, the compression amount at the top of the outer insulating ring 3 is too small, the outer insulating ring 3 will not be able to play the proper sealing role, thus the sealing performance of the battery cannot be guaranteed.

[0039] If the ratio H1 / L1 of the minimum height H1 at the top flange 41 of the outer insulating ring 3 to the width L1 of the side extension 31 is set too large, that is, the compression of the top of the outer insulating ring 3 is too large, it is easy to cause plastic deformation of the outer insulating ring 3 and permanent failure, thereby causing poor battery sealing.

[0040] Therefore, in this application, the ratio H1 / L1 of the minimum height H1 of the outer insulating ring 3 at the top flange 41 pressing point to the width L1 of the side extension 31 is set to 45.6% to 60.3%, which further prevents the compression of the top flange 41 on the top of the outer insulating ring 3 from being too large or too small, ensuring the sealing of the cylindrical lithium-ion battery, and thus ensuring the performance of the cylindrical lithium-ion battery.

[0041] In practical implementation, preferably, the ratio H1 / L1 of the minimum height H1 of the outer insulating ring 3 at the top flange 41 crimping point to the width L1 of the side extension 31 is set to 52.9%.

[0042] In this embodiment, the outer insulating ring 3 further includes an upper extension 32, which extends laterally on the upper surface of the upper cover plate 1. When the cap assembly is connected to the housing 4, the top flange 41 of the housing 4 is pressed against the upper extension 32, so that the upper extension 32 isolates the upper surface of the upper cover plate 1 from the top flange 41 of the housing 4.

[0043] In this application, the minimum height H1 of the outer insulating ring 3 at the top flange 41 is the minimum thickness of the upper extension 32 after being pressed by the top flange 41. When the top flange 41 is pressed against the upper extension 32, some material of the upper extension 32 is extruded, thereby forming an upturned portion 321 at the end of the upper extension 32.

[0044] In this application, the maximum height of the upturned portion 321 from the upper cover plate 1 is set to H2. Since the formation of the upturned portion 321 is a process of natural creep of the material under the compression of the upper extension portion 32 by the top flange 41, if the maximum height H2 of the upturned portion 321 from the upper cover plate 1 is too small, it indicates that the creep of the upper extension portion 32 under the compression of the top flange 41 is insufficient, which indirectly reflects that the compression of the upper extension portion 32 is too small; similarly, if the maximum height H2 of the upturned portion 321 from the upper cover plate 1 is too large, it indicates that the creep of the upper extension portion 32 under the compression of the top flange 41 is too large, which indirectly reflects that the compression of the upper extension portion 32 is too large.

[0045] Therefore, in this application, the ratio H2 of the maximum height H2 of the upturned portion 321 from the top cover plate 1 to the radius R1 of the cylindrical lithium-ion battery is set to 5% to 7%, thereby further preventing the compression of the top flange 41 on the top of the outer insulating ring 3 from being too large or too small, ensuring the sealing performance of the cylindrical lithium-ion battery, and thus ensuring the performance of the cylindrical lithium-ion battery. In actual implementation, preferably, the ratio H2 of the maximum height H2 of the upturned portion 321 from the top cover plate 1 to the radius R1 of the cylindrical lithium-ion battery is set to 6%.

[0046] As mentioned in the above embodiment, the maximum height H2 of the upturned portion 321 from the upper cover plate 1 reflects the amount of compression of the upper extension portion 32. However, in order to more accurately reflect the amount of compression of the upper extension portion 32 through the maximum height H2 of the upturned portion 321 from the upper cover plate 1, the angle formed between the upturned portion 321 and the upper cover plate 1 in the horizontal direction needs to be at a suitable angle.

[0047] In this embodiment, the angle formed between the upturned portion 321 and the upper cover plate 1 in the horizontal direction is set to A. Since, under the same compression amount of the upper extension 32, the larger the angle A formed between the upturned portion 321 and the upper cover plate 1 in the horizontal direction, the larger the maximum height H2 of the upturned portion 321 from the upper cover plate 1; the smaller the angle A formed between the upturned portion 321 and the upper cover plate 1 in the horizontal direction, the smaller the maximum height H2 of the upturned portion 321 from the upper cover plate 1.

[0048] Therefore, if the angle A formed by the upturned portion 321 and the upper cover plate 1 in the horizontal direction is too large, even if the compression amount of the upper extension portion 32 does not reach the required compression amount, the maximum height H2 of the upturned portion 321 from the upper cover plate 1 may still reach the range specified above. Conversely, if the angle A formed by the upturned portion 321 and the upper cover plate 1 in the horizontal direction is too small, even if the compression amount of the upper extension portion 32 reaches the required compression amount, the maximum height H2 of the upturned portion 321 from the upper cover plate 1 may not reach the range specified above, thus causing the maximum height H2 of the upturned portion 321 from the upper cover plate 1 to not accurately reflect the magnitude of the compression amount of the upper extension portion 32.

[0049] Therefore, in this application, the angle A formed by the upturned portion 321 and the upper cover plate 1 in the horizontal direction is set to 27° to 47°. By setting the angle A between the upturned portion 321 and the upper cover plate 1 in the horizontal direction within a suitable range, the maximum height H2 of the upturned portion 321 from the upper cover plate 1 more accurately reflects the amount of compression of the upper extension 32, thereby further preventing the compression of the top flange 41 on the top of the outer insulating ring 3 from being too large or too small, ensuring the sealing of the cylindrical lithium-ion battery, and thus ensuring the performance of the cylindrical lithium-ion battery. In actual implementation, preferably, the angle A formed by the upturned portion 321 and the upper cover plate 1 in the horizontal direction is set to 37°.

[0050] In this embodiment, the outer insulating ring 3 further includes a lower extension 33, which extends laterally on the lower surface of the explosion-proof sheet 2. When the cap assembly is connected to the housing 4, the bottom flange 42 of the housing 4 is pressed against the lower extension 33, so that the lower extension 33 isolates the lower surface of the explosion-proof sheet 2 from the bottom flange 42 of the housing 4. Thus, the upper surface of the upper cover plate 1 is isolated from the top flange 41 of the housing 4 by the upper extension 32, the side extension 31 isolates the outer surfaces of the upper cover plate 1 and the explosion-proof sheet 2 from the inner wall of the housing 4, and the lower extension 33 isolates the lower surface of the explosion-proof sheet 2 from the bottom flange 42 of the housing 4, thereby achieving insulation between the cap assembly and the housing 4.

[0051] In this application, the minimum height of the lower extension 33 at the bottom flange 42 crimping point is set to H3. In actual use, if the compression of the lower extension 33 by the bottom flange 42 is too large, that is, if the compression of the bottom of the outer insulating ring 3 is too large, it is easy to cause plastic deformation of the outer insulating ring 3 and permanent failure, thereby causing poor battery sealing; if the compression of the lower extension 33 by the bottom flange 42 is too small, that is, if the compression of the bottom of the outer insulating ring 3 is too small, it will also cause the outer insulating ring 3 to fail to achieve the proper sealing effect, thereby causing the battery sealing performance to be compromised.

[0052] Therefore, in this application, the ratio H3 of the minimum height H3 of the lower extension 33 at the bottom flange 42 pressing point to the radius R1 of the cylindrical lithium-ion battery is set between 2.4% and 3.9% to prevent the minimum height H1 of the outer insulating ring 3 at the bottom flange 42 pressing point from being too large or too small, thereby preventing the compression of the bottom flange 42 on the bottom of the outer insulating ring 3 from being too large or too small, ensuring the sealing of the cylindrical lithium-ion battery, and thus ensuring the performance of the cylindrical lithium-ion battery.

[0053] In practical implementation, preferably, the ratio H3 of the minimum height H3 of the lower extension 33 at the bottom flange 42 pressing point to the radius R1 of the cylindrical lithium-ion battery is set to 3.1%.

[0054] In this embodiment, when the bottom flange 42 of the housing 4 is pressed against the lower extension 33, a portion of the material of the lower extension 33 is extruded. Through natural material creep, a recessed portion 331 is formed at the end of the lower extension 33. In this application, the angle formed between the recessed portion 331 and the explosion-proof sheet 2 in the horizontal direction is set to B. In actual use, the size of the angle B formed between the recessed portion 331 and the explosion-proof sheet 2 in the horizontal direction also reflects the magnitude of the compression of the lower extension 33.

[0055] Therefore, in this application, the angle B formed by the recessed portion 331 and the explosion-proof sheet 2 in the horizontal direction is set between 8° and 28°, thereby further preventing the compression of the bottom flange 42 on the bottom of the outer insulating ring 3 from being too large or too small, ensuring the sealing of the cylindrical lithium-ion battery, and thus ensuring the performance of the cylindrical lithium-ion battery. In actual implementation, preferably, the angle B formed by the recessed portion 331 and the explosion-proof sheet 2 in the horizontal direction is set to 18°.

[0056] In this embodiment, the maximum length of the upper extension 32 is set to L2. In actual use, since the upper extension 32 extends laterally on the upper surface of the upper cover plate 1 and has a protrusion on the upper surface of the upper cover plate 1 for welding with other batteries during the battery assembly process, if the maximum length L2 of the upper extension 32 is set too large, it may cause interference between the upper extension 32 and the protrusion of the upper cover plate 1, thereby affecting the battery assembly.

[0057] If the maximum length L2 of the upper extension 32 is set too small, that is, the contact area between the upper extension 32 and the upper surface of the upper cover plate 1 is too small, it will affect the insulation effect of the outer insulating ring 3 on the upper cover plate 1 and the shell 4, and the sealing performance of the battery cannot be guaranteed, thus affecting the performance of the cylindrical lithium-ion battery.

[0058] Therefore, in this application, the ratio L2 of the maximum length of the upper extension 32 to the radius R1 of the cylindrical lithium-ion battery, L2 / R1, is set to 21% to 30.5%. This prevents the maximum length L2 of the upper extension 32 from being too large or too small, thus preventing interference between the upper extension 32 and the protrusion of the upper cover plate 1, ensuring the assembly of the cylindrical lithium-ion battery, and also ensuring the insulation effect of the upper extension 32 and the sealing performance of the battery, thereby ensuring the performance of the cylindrical lithium-ion battery. In practical implementation, preferably, the ratio L2 of the maximum length of the upper extension 32 to the radius R1 of the cylindrical lithium-ion battery, L2 / R1, is set to 25.7%.

[0059] In this embodiment, the maximum length of the lower extension 33 is set to L3. When the bottom flange 42 of the housing 4 is pressed against the lower extension 33, part of the material of the lower extension 33 is extruded. Through natural material creep, a recessed portion 331 is formed at the end of the lower extension 33. Therefore, in actual use, if the maximum length L3 of the lower extension 33 is set too large, the recessed portion 331 will extend too far downward, causing interference between the recessed portion 331 and the core inside the housing 4, squeezing the core, affecting the performance of the core, and thus affecting the performance of the cylindrical lithium-ion battery.

[0060] If the maximum length L3 of the lower extension 33 is set too small, that is, the contact area between the lower extension 33 and the lower surface of the explosion-proof sheet 2 is too large, on the one hand, it will affect the insulation effect of the outer insulating ring 3 on the explosion-proof sheet 2 and the shell 4, and on the other hand, it will cause the battery's sealing performance to be compromised, thereby affecting the performance of the cylindrical lithium-ion battery.

[0061] Therefore, in this application, the ratio L3 / R1 of the maximum length L3 of the lower extension 33 to the radius R1 of the cylindrical lithium-ion battery is set to 17.1% to 26.7%, thereby preventing the maximum length L3 of the lower extension 33 from being too large or too small. This prevents interference between the recessed portion 331 of the lower extension 33 and the core, while also ensuring the insulation effect of the outer insulating ring 3 and the sealing performance of the battery, thus guaranteeing the performance of the cylindrical lithium-ion battery. In practical implementation, preferably, the ratio L3 / R1 of the maximum length L3 of the lower extension 33 to the radius R1 of the cylindrical lithium-ion battery is set to 21.9%.

[0062] In this embodiment, the minimum width L1 of the side extension 31 is set between 0.6mm and 0.76mm. In actual implementation, the value of L1 can be determined first, and then the value of H1 can be determined according to the ratio H1 / L1, thereby preventing the compression of the top flange 41 on the top of the outer insulating ring 3 from being too large or too small, ensuring the sealing of the cylindrical lithium-ion battery, and thus ensuring the performance of the cylindrical lithium-ion battery. Preferably, the minimum width L1 of the side extension 31 is set to 0.68mm.

[0063] In this embodiment, the radius R1 of the cylindrical lithium-ion battery is set between 9.5 mm and 11.5 mm. In actual implementation, the value of R1 can be determined first, and then the values ​​of H1, H2, H3, L2, and L3 can be determined according to the ratios H1 / R1, H2 / R1, H3 / R1, L2 / R1, and L3 / R1, thereby completing the size design of the cylindrical lithium-ion battery. Preferably, the radius R1 of the cylindrical lithium-ion battery is set to 10.5 mm.

[0064] It is foreseeable that, since the ratios H1 / R1 and H1 / L1 are defined in this application, in actual implementation, the value of R1 can be determined first, and the range of H1 can be obtained based on the range of the ratio H1 / R1; then, the value of L1 can be determined, and the range of H1 can be further narrowed based on the range of the ratio H1 / L1, and finally the value of H1 can be determined. This further prevents the compression of the top flange 41 on the top of the outer insulating ring 3 from being too large or too small, ensuring the sealing of the cylindrical lithium-ion battery, and thus ensuring the performance of the cylindrical lithium-ion battery.

[0065] 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.

[0066] 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.

[0067] 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 cylindrical lithium-ion battery, characterized in that: The device includes a top cover plate (1), an explosion-proof sheet (2), an outer insulating ring (3), and a housing (4). The explosion-proof sheet (2) is located at the bottom of the top cover plate (1). The outer insulating ring (3) is located on the outer periphery of the top cover plate (1) and the explosion-proof sheet (2) to insulate the top cover plate (1) and the explosion-proof sheet (2) from the housing (4). The housing (4) is bent outside the outer insulating ring (3) to form a top flange (41) and a bottom flange (42). The top flange (41) is pressed against the top of the outer insulating ring (3), and the bottom flange (42) is pressed against the bottom of the outer insulating ring (3). The minimum height H1 of the outer insulating ring (3) at the point where it is pressed against the top flange (41) is 3% to 4% of the radius R1 of the cylindrical lithium-ion battery.

2. A cylindrical lithium-ion battery as described in claim 1, characterized in that: The outer insulating ring (3) includes a side extension (31) extending vertically on the outer side of the upper cover plate (1) and the explosion-proof sheet (2), wherein the minimum width L1,H1 / L1 of the side extension (31) is 45.6% to 60.3%.

3. A cylindrical lithium-ion battery as described in claim 2, characterized in that: The outer insulating ring (3) also includes an upper extension (32) extending laterally on the upper surface of the upper cover plate (1), the top flange (41) is pressed onto the upper extension (32), and an upturned portion (321) is formed at the end of the upper extension (32). The maximum height H2 of the upturned portion (321) from the upper cover plate (1) is 5% to 7% of the ratio H2 / R1 of the radius R1 of the cylindrical lithium-ion battery.

4. A cylindrical lithium-ion battery as described in claim 2, characterized in that: The outer insulating ring (3) also includes a lower extension (33) extending laterally on the lower surface of the explosion-proof sheet (2), the bottom flange (42) is pressed against the lower extension (33), and the minimum height H3 of the lower extension (33) at the bottom flange (42) is 2.4% to 3.9% of the ratio H3 / R1 to the radius R1 of the cylindrical lithium-ion battery.

5. A cylindrical lithium-ion battery as described in claim 3, characterized in that: The angle A formed by the upturned part (321) and the upper cover plate (1) in the horizontal direction is 27° to 47°.

6. A cylindrical lithium-ion battery as described in claim 4, characterized in that: When the bottom flange (42) is pressed onto the lower extension (33), a recessed portion (331) is formed at the end of the lower extension (33), and the angle B formed between the recessed portion (331) and the explosion-proof sheet (2) in the horizontal direction is 8° to 28°.

7. A cylindrical lithium-ion battery as described in claim 3, characterized in that: The ratio of the maximum length L2 of the upper extension (32) to the radius R1 of the cylindrical lithium-ion battery, L2 / R1, is 21% to 30.5%.

8. A cylindrical lithium-ion battery as described in claim 4, characterized in that: The ratio of the maximum length L3 of the lower extension (33) to the radius R1 of the cylindrical lithium-ion battery, L3 / R1, is 17.1% to 26.7%.

9. A cylindrical lithium-ion battery as described in claim 2, characterized in that: The minimum width L1 of the side extension (31) is 0.6 mm to 0.76 mm.

10. A cylindrical lithium-ion battery as described in claim 1, characterized in that: The radius R1 of the cylindrical lithium-ion battery is 9.5 mm to 11.5 mm.

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