A lithium-ion cylindrical secondary battery

Abstract

This utility model relates to the field of cylindrical battery technology and proposes a lithium-ion cylindrical secondary battery, including a housing, a gasket, and a rubber ring. The housing has a protrusion inside; the gasket is disposed inside the housing and abuts against the bottom side of the protrusion; the rubber ring is fixedly disposed on the positive electrode cap and spaced above the gasket, with a minimum distance H between the gasket and the rubber ring. 41 The end face radius of the lithium-ion cylindrical secondary battery is R1, H 41 / R1 = 3.6% - 5.5%. This utility model, by reasonably setting the distance between the gasket and the rubber ring, not only makes the gasket more compact with the positive electrode cap and rubber ring, improving the battery capacity and energy density, but also avoids interference and collision between the gasket and the positive electrode cap and rubber ring during assembly, reducing the assembly difficulty of the battery and thus effectively improving the overall performance of the battery.

Description

Technical Field

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

[0002] Lithium-ion rechargeable batteries have become a core power source for portable electronic devices, hybrid vehicles, and electric vehicles due to their significant advantages such as high operating voltage, high energy density, and long cycle life. Among them, cylindrical structures occupy an important market share due to their high mechanical strength, high production efficiency, and excellent space utilization.

[0003] The grooving process is an important step in the production of cylindrical lithium-ion batteries. For example, the cylindrical battery disclosed in invention patent CN118572315A has an upper insulator between the grooved part of the electrode assembly and the cylindrical shell. This not only fixes the electrode assembly and prevents it from shaking during battery use, but also insulates the electrode assembly and the cylindrical shell to avoid short circuits.

[0004] In the above technical solution, the upper insulator occupies a certain space. In order to achieve normal assembly of the battery, the cover assembly and the upper insulator need to be spaced apart. However, the distance between the cover assembly and the upper insulator is not set reasonably. If the distance is too large, it will occupy the internal space of the battery, resulting in a decrease in the battery's capacity and energy density. If the distance is too small, the cover assembly will easily interfere with and collide with the upper insulator when assembling the battery, causing assembly difficulties and affecting the overall performance of the battery. Utility Model Content

[0005] In view of this, this utility model proposes a cylindrical lithium-ion secondary battery. By reasonably setting the distance between the gasket and the rubber ring, the battery capacity and assembly efficiency can be balanced, thereby effectively improving the overall performance of the battery.

[0006] The technical solution of this utility model is implemented as follows: This utility model provides a cylindrical lithium-ion secondary battery, including a housing, a gasket, and a rubber ring. The housing has a protrusion inside; the gasket is disposed inside the housing and abuts against the bottom side of the protrusion; the rubber ring is fixedly disposed on the positive electrode cap and spaced above the gasket, with a minimum distance of H between the gasket and the rubber ring. 41 The end face radius of the lithium-ion cylindrical secondary battery is R1, H 41 / R1 = 3.6% - 5.5%.

[0007] Based on the above technical solutions, preferably, the thickness of the gasket is H. 40 H 40 / R1 = 1.9% - 3.8%.

[0008] Based on the above technical solution, preferably, the gasket ring has a ring-shaped structure with a ring width of L. 40 L 40 =2.6-3.4mm.

[0009] More preferably, it also includes a positive current collector, which is located inside the gasket ring, with a minimum distance of L between them. 43 L 43 =0.45-1.25mm.

[0010] Based on the above technical solutions, preferably, it further includes a positive electrode coating, wherein the positive electrode coating is abutted between the gasket ring and the positive electrode tab, and the positive electrode coating has a ring-shaped structure with a ring width of L. 41 L 41 =2.1-2.9mm.

[0011] More preferably, the portion of the gasket ring closest to the axis of the lithium-ion cylindrical secondary battery does not contact the positive electrode coating, forming a suspended ring, the width of which is L. 42 L 42 =0.5-1.1mm.

[0012] Based on the above technical solutions, preferably, the length of the protrusion protruding from the inner wall of the housing is L. 30 L 30 / R1 = 15.2% - 24.8%.

[0013] Based on the above technical solutions, preferably, an insulating ring is also included. The insulating ring abuts against the top side of the protrusion and is fixedly disposed between the housing and the positive electrode cap. The rubber ring is located inside the insulating ring, and the minimum distance between the two is L. 32 L 32 / R1 = 3.8% - 5.7%.

[0014] Based on the above technical solutions, the preferred option is H. 41 =0.38-0.58mm.

[0015] Based on the above technical solutions, the preferred value is R1 = 9.5-11.5mm.

[0016] The lithium-ion cylindrical secondary battery of this invention has the following advantages over the prior art:

[0017] (1) By reasonably setting the distance between the gasket and the rubber ring, not only can the gasket be more compact with the positive electrode cap and the rubber ring, thus improving the battery capacity and energy density, but also the gasket can be prevented from interfering with the positive electrode cap and the rubber ring during assembly, reducing the assembly difficulty of the battery and thus effectively improving the overall performance of the battery.

[0018] (2) By further limiting the specifications of the insulating ring, protrusion and positive electrode coating, the safety capability and processing cost of the battery can be balanced, and the assembly difficulty of the battery can be further reduced, thereby increasing the battery capacity and energy density. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a partial cross-sectional view of a lithium-ion cylindrical secondary battery according to the present invention.

[0021] Figure 2 This is a cross-sectional view of the gasket ring in a lithium-ion cylindrical secondary battery according to the present invention.

[0022] Figure 3 This is a cross-sectional view of the position between the gasket ring and the rubber ring in a lithium-ion cylindrical secondary battery according to this utility model.

[0023] The components are: 1. Shell; 11. Protrusion; 2. Washer ring; 21. Suspended ring; 3. Rubber ring; 4. Positive electrode cap; 5. Positive electrode current collector; 6. Positive electrode coating; 7. Insulating ring. Detailed Implementation

[0024] The technical solutions of this utility model will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0025] Lithium-ion cylindrical rechargeable batteries are widely used rechargeable batteries with a cylindrical shape. Common models include 18650 and 21700. Lithium-ion cylindrical rechargeable batteries have advantages such as stable structure, high energy density, and long cycle life, and are widely used in consumer electronics (such as laptops, power tools, and vacuum cleaners), electric vehicles, and energy storage systems.

[0026] The working principle of lithium-ion batteries is based on the reversible migration of lithium ions between the positive and negative electrodes. During charging, lithium ions are deintercalated from the positive electrode, migrate through the electrolyte to the negative electrode, and intercalate into the negative electrode material. During discharging, lithium ions are deintercalated from the negative electrode, return to the positive electrode, and generate current.

[0027] This utility model discloses a cylindrical lithium-ion secondary battery, comprising a casing 1, a gasket 2, a rubber ring 3, a positive electrode cap 4, a positive electrode current collector 5, a positive electrode coating 6, and an insulating ring 7.

[0028] The housing 1 is a barrel-shaped structure with one end open, and the core is placed inside the housing 1. The housing 1 has a protrusion 11 inside, which protrudes into the housing 1. The washer 2 is placed inside the housing 1 and abuts against the bottom side of the protrusion 11 and the top side of the positive electrode tab on the core, that is, the core is fixed by the protrusion 11.

[0029] The gasket 2 is made of insulating material. When it is located between the protrusion 11 and the positive electrode tab, it can prevent a short circuit between the positive electrode tab and the protrusion 11, thus improving the safety of the battery.

[0030] The protrusion 11 is preferably formed by grooving the housing 1. After the core and the washer ring 2 are placed into the housing 1 in sequence, the periphery of the housing 1 is grooved using a grooving machine, causing the housing 1 to bend inward in a localized area to form the protrusion 11. This forming method of the protrusion 11 is relatively simple, which can reduce the processing difficulty of the protrusion 11 and improve the production efficiency of the protrusion 11.

[0031] To improve the insulation effect between the core and the shell 1, a layer of insulating material is applied to the core. The coating covers the periphery of the core and extends to the end of the core, covering the outer edge of the top side of the positive electrode tab. The position where the coating covers the positive electrode tab is called positive electrode coating 6. Positive electrode coating 6 is abutted between the gasket ring 2 and the positive electrode tab.

[0032] Both the positive electrode coating 6 and the gasket 2 are ring-shaped structures, preferably circular ring-shaped structures with uniform ring width.

[0033] To improve the installation efficiency of the coating, the ring width of the positive electrode coating 6 should not be too long, such as... Figure 2 and Figure 3As shown, the positive electrode coating 6 only abuts against the outer edge of the bottom side of the gasket 2. The position on the gasket 2 near the axis of the lithium-ion cylindrical secondary battery does not abut against the positive electrode coating 6. The position on the gasket 2 that does not abut against the positive electrode coating 6 is the suspended ring 21, and the suspended ring 21 is also a ring structure.

[0034] The positive current collector 5 and the positive cap 4 are used to establish conductivity with the positive electrode tab, enabling the positive electrode tab to connect to the electrical equipment. The positive current collector 5 is welded and fixed to the positive electrode tab, and the positive cap 4 is welded and fixed to the positive current collector 5. The insulating ring 7 is fixedly disposed between the housing 1 and the positive cap 4. The insulating ring 7 and the positive cap 4 not only seal the opening of the housing 1, but also prevent short circuit between the positive cap 4 and the housing 1.

[0035] like Figure 2 As shown, the open end of the housing 1 is provided with a bend, which abuts against the top side of the insulating ring 7, and together with the protrusion 11 abuts against the bottom side of the insulating ring 7, thereby fixing the housing 1 and the insulating ring 7.

[0036] As a component connecting the positive electrode tab and the positive electrode cap 4, the positive electrode current collector 5 must pass through the gasket 2 and the positive electrode sheath 6. Preferably, the positive electrode current collector 5 is located inside the gasket 2 and the positive electrode sheath 6 respectively, and the positive electrode current collector 5 is spaced apart from the inner wall of the gasket 2 and the inner wall of the positive electrode sheath 6 to avoid collision between the positive electrode current collector 5 and the gasket 2 and the positive electrode sheath 6 during assembly.

[0037] The positive electrode cap 4 generally includes an explosion-proof sheet and a lower end plate. The lower end plate is welded and fixed between the positive electrode current collector 5 and the explosion-proof sheet. In order to ensure timely power disconnection in the event of thermal runaway, the middle position of the explosion-proof sheet is welded to the middle position of the lower end plate, while the outer edge of the explosion-proof sheet is spaced apart from the outer edge of the lower end plate.

[0038] To prevent the outer edge of the explosion-proof sheet from communicating with the outer edge of the lower end plate, the rubber ring 3 is usually fixed between the outer edge of the explosion-proof sheet and the outer edge of the lower end plate.

[0039] like Figure 2 and Figure 3 As shown, the rubber ring 3 is fixedly mounted on the positive electrode cap 4, and the rubber ring 3 is spaced above the gasket 2 to avoid collision between the rubber ring 3 and the gasket 2 during assembly. In order to ensure the venting effect of the battery and improve the structural compactness of the positive electrode cap 4, the rubber ring 3 and the insulating ring 7, it is preferable to place the rubber ring 3 inside the insulating ring 7 and space it from the inner wall of the insulating ring 7.

[0040] like Figures 1-3 As shown, the end face radius of the lithium-ion cylindrical secondary battery is R1, and the ring width of the gasket 2 is L. 40 The thickness of washer 2 is H. 40The minimum distance between washer 2 and rubber ring 3 is H. 41 The minimum distance between the rubber ring 3 and the insulating ring 7 is L. 32 The minimum distance between the gasket 2 and the positive current collector 5 is L. 43 The ring width of the positive electrode coating 6 is L. 41 The width of the suspended ring 21 is L. 42 The length of the protrusion 11 protruding from the inner wall of the shell 1 is L. 30 .

[0041] In some embodiments, R1 = 9.5-11.5 mm, that is, the end face radius of the lithium-ion cylindrical secondary battery is 9.5 mm, 10.5 mm or 11.5 mm, etc.

[0042] In some embodiments, H 41 / R1 = 3.6%-5.5%, meaning the minimum distance between the gasket 2 and the rubber ring 3 is 3.6%, 4.5%, or 5.5% of the radius of the lithium-ion cylindrical secondary battery end face, etc. If H 41 If / R1 < 3.6%, then the distance between the gasket 2 and the rubber ring 3 is too small. During assembly of the positive electrode cap 4 and the housing 1, the rubber ring 3 on the positive electrode cap 4 is prone to interference and collision with the gasket 2 inside the housing 1, increasing the difficulty of battery assembly. If H 41 If R1 > 5.5%, then the distance between the gasket 2 and the rubber ring 3 is too large. With a fixed total battery height, an excessively large distance between the gasket 2 and the rubber ring 3 will occupy the internal space of the battery, resulting in a decrease in battery capacity.

[0043] Furthermore, H 41 =0.38-0.58mm, meaning the minimum distance between washer 2 and rubber ring 3 is 0.38mm, 0.48mm, or 0.58mm, etc. If H 41 If the distance is less than 0.38mm, the gap between the gasket 2 and the rubber ring 3 is too small. During assembly of the positive electrode cap 4 and the housing 1, the rubber ring 3 on the positive electrode cap 4 is prone to interference and collision with the gasket 2 inside the housing 1, increasing the difficulty of battery assembly. If H 41 If the gap is greater than 0.58mm, the distance between the spacer ring 2 and the rubber ring 3 is too large. With a fixed total battery height, an excessively large gap between the spacer ring 2 and the rubber ring 3 will occupy the internal space of the battery, resulting in a decrease in battery capacity.

[0044] In some embodiments, H 40 / R1 = 1.9%-3.8%, meaning the thickness of gasket 2 is 1.9%, 2.8%, or 3.8% of the radius of the end face of the lithium-ion cylindrical secondary battery, etc. If H 40 If / R1 < 1.9%, then the thickness of gasket 2 is too small, its strength is too low, and it is easily deformed. At the same time, insufficient thickness of gasket 2 will also lead to insufficient insulation withstand voltage, making it prone to breakdown and short circuit. If H 40If R1 > 3.8%, then the thickness of the spacer ring 2 is too large, which will occupy more space inside the battery, compress the height of the battery core, and cause the battery capacity to decrease.

[0045] In some embodiments, L 40 =2.6-3.4mm, meaning the ring width of washer 2 is 2.6mm, 3mm, or 3.4mm, etc. If L 40 If the diameter is less than 2.6mm, the ring width of the spacer ring 2 is too small. The protrusion 11, located near the axis of the lithium-ion cylindrical secondary battery, is prone to contact with the positive electrode tab, leading to a significant risk of short circuit in the battery. If L 40 If the width of the gasket 2 is greater than 3.4mm, it will interfere with the positive current collector 5, affecting the bending and assembly of the positive current collector 5.

[0046] In some embodiments, L 43 =0.45-1.25mm, meaning the minimum distance between the gasket 2 and the positive current collector 5 is 0.45mm, 0.85mm, or 1.25mm, etc. If L 43 If the distance between the spacer ring 2 and the positive current collector 5 is less than 0.45mm, it will interfere with the positive current collector 5, affecting the bending and assembly of the positive current collector 5; if L 43 If the gap between the spacer ring 2 and the positive current collector 5 is greater than 1.25mm, the ring width of the spacer ring 2 will be reduced. The protrusion 11, which is close to the axis of the lithium-ion cylindrical secondary battery, is likely to come into contact with the positive electrode tab, and the battery will have a greater risk of short circuit.

[0047] In some embodiments, L 41 =2.1-2.9mm, meaning the ring width of the positive electrode coating 6 is 2.1mm, 2.5mm, or 2.9mm, etc. If L 41 If the diameter is less than 2.1mm, the ring width of the positive electrode coating 6 is too small, reducing the reliability of the coating and the connection between the positive electrode coating 6 and the core. The positive electrode coating 6 is prone to rebound, leading to an increased coating defect rate in the core. If L... 41 If the width is greater than 2.9mm, the ring width of the positive electrode coating 6 is too large. The gasket ring 2 will not only fail to provide better insulation for the battery, but will also increase the weight and manufacturing cost of the battery, and reduce the capacity and energy density of the battery.

[0048] In some embodiments, L 42 =0.5-1.1mm, meaning the width of the suspended ring 21 is 0.5mm, 0.8mm, or 1.1mm, etc. If L 42 If the width of the suspended ring 21 is less than 0.5mm, the secondary insulation and support provided by the pad ring 2 will be weak; if L 42If the width of the suspended ring 21 is greater than 1.1mm, the ring width will be too large. The pad ring 2 will not only fail to provide better insulation for the battery, but will also increase the weight and manufacturing cost of the battery, and reduce the capacity and energy density of the battery.

[0049] In some embodiments, L 30 / R1 = 15.2% - 24.8%, meaning the length of the protrusion 11 protruding from the inner wall of the casing 1 is 15.2%, 20%, or 24.8% of the radius of the end face of the lithium-ion cylindrical secondary battery, etc. If L 30 If / R1 < 15.2%, then the length of the protrusion 11 protruding from the inner wall of the housing 1 is too small. The supporting and fixing effect of the protrusion 11 on the gasket 2 and the insulating ring 7, as well as the sealing effect, are relatively poor, which will affect the sealing reliability of the battery; if L 30 If R1 > 24.8%, then the length of the protrusion 11 protruding from the inner wall of the shell 1 is too large. This requires a greater height for the shell 1 without grooving, which will increase the manufacturing cost of the battery. At the same time, the excessive length of the protrusion 11 protruding from the inner wall of the shell 1 will also weaken the structural strength of the protrusion 11. The position of the protrusion 11 near the axis of the lithium-ion cylindrical secondary battery is prone to collapse, which will not only occupy the internal space of the battery and affect the energy density and capacity of the battery, but also cause a short circuit risk.

[0050] In some embodiments, L 32 / R1 = 3.8%-5.7%, meaning the minimum distance between the rubber ring 3 and the insulating ring 7 is 3.8%, 4.8%, or 5.7% of the radius of the end face of the lithium-ion cylindrical secondary battery, etc. If L 32 If / R1 < 3.8%, then the distance between the rubber ring 3 and the insulating ring 7 is too small. During the sealing process of the casing 1, if the sealing pressure fluctuates or changes, it will cause interference between the insulating ring 7 and the rubber ring 3, affecting the battery performance; if L 32 If R1 > 5.7%, the gap between the rubber ring 3 and the insulating ring 7 is too large, indicating that the compression deformation on the side of the insulating ring 7 is insufficient, which will affect the sealing reliability of the battery.

[0051] In a preferred embodiment, R1 = 10.5 mm, H 41 / R1=4.6%, H 40 / R1=2.9%, L 40 =3mm, L 43 =0.85mm, L 41 =2.5mm, L 42 =0.79mm, L 30 / R1=20%, L 32 / R1=4.8% can not only reduce the difficulty of battery assembly, improve battery assembly efficiency, and reduce battery manufacturing costs, but also reduce the risk of battery short circuits, improve battery safety, and increase battery capacity and energy density, giving the battery good overall performance.

[0052] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A lithium-ion cylindrical secondary battery, characterized in that: Includes a housing (1), a gasket (2), and a rubber ring (3), wherein, The housing (1) is provided with a protrusion (11); The washer ring (2) is disposed inside the housing (1) and abuts against the bottom side of the protrusion (11); The rubber ring (3) is fixedly mounted on the positive electrode cap (4) and spaced above the gasket (2). The minimum distance between the gasket (2) and the rubber ring (3) is H. 41 The end face radius of the lithium-ion cylindrical secondary battery is R1, H 41 / R1 = 3.6% - 5.5%.

2. A lithium-ion cylindrical secondary battery as described in claim 1, characterized in that: The thickness of the washer (2) is H 40 H 40 / R1 = 1.9% - 3.8%.

3. A lithium-ion cylindrical secondary battery as described in claim 1, characterized in that: The gasket (2) has a ring-shaped structure with a ring width of L. 40 L 40 =2.6-3.4mm.

4. A lithium-ion cylindrical secondary battery as described in claim 3, characterized in that: It also includes a positive current collector (5), which is located inside the gasket (2), and the minimum distance between the two is L. 43 L 43 =0.45-1.25mm.

5. A lithium-ion cylindrical secondary battery as described in claim 1, characterized in that: It also includes a positive electrode coating (6), which is abutted between the gasket ring (2) and the positive electrode tab. The positive electrode coating (6) has a ring structure with a ring width of L. 41 L 41 =2.1-2.9mm.

6. A lithium-ion cylindrical secondary battery as described in claim 5, characterized in that: The gasket (2) is positioned near the axis of the lithium-ion cylindrical secondary battery and does not contact the positive electrode coating (6), forming a suspended ring (21). The width of the suspended ring (21) is L. 42 L 42 =0.5-1.1mm.

7. A lithium-ion cylindrical secondary battery as described in claim 1, characterized in that: The protrusion (11) protrudes from the inner wall of the housing (1) by a length of L. 30 L 30 / R1 = 15.2% - 24.8%.

8. A lithium-ion cylindrical secondary battery as described in claim 1, characterized in that: It also includes an insulating ring (7), which abuts against the top side of the protrusion (11) and is fixedly disposed between the housing (1) and the positive electrode cap (4). The rubber ring (3) is located inside the insulating ring (7), and the minimum distance between the two is L. 32 L 32 / R1 = 3.8% - 5.7%.

9. A lithium-ion cylindrical secondary battery as described in any one of claims 1-8, characterized in that: H 41 =0.38-0.58mm。 10. A lithium-ion cylindrical secondary battery as described in any one of claims 1-8, characterized in that: R1 = 9.5-11.5mm.

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