A cylindrical lithium-ion battery

Abstract

The application discloses a cylindrical lithium ion battery and belongs to the technical field of batteries. The cylindrical lithium ion battery comprises a roll core assembly, a shell and a cap assembly. The roll core assembly comprises a first positioning part. The shell is wrapped outside the roll core assembly, and one end of the shell is open. The cap assembly is arranged at the open end of the shell. The cap assembly comprises a top cover and a sealing ring. The top cover is located at the upper part of the roll core assembly. The sealing ring is located between the top cover and the shell to seal and insulate the top cover and the shell. The top cover comprises a second positioning part. The second positioning part and the first positioning part are connected in a matched mode to position and fix the roll core assembly. The cylindrical lithium ion battery has a simple structure, simplified processing steps, reduced cost and improved safety.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to a cylindrical lithium-ion battery. Background Technology

[0002] Traditional cylindrical lithium-ion battery cap assemblies typically consist of five parts: a steel cap, an explosion-proof valve, a small aluminum sheet, a sealing ring, and an insulating gasket. This structure is complex, difficult to manufacture, and increases costs. Furthermore, when the battery is subjected to an impact that causes the core and casing to rotate relative to each other, the tabs can easily detach from the cap assembly bracket, affecting the battery's performance.

[0003] Therefore, there is an urgent need for a cylindrical lithium-ion battery with a simple structure and high safety to solve the aforementioned technical problems in the existing technology. Summary of the Invention

[0004] The purpose of this invention is to provide a cylindrical lithium-ion battery that has a simple structure, simplifies the processing steps, reduces costs, and improves battery safety.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A cylindrical lithium-ion battery, comprising:

[0007] The core assembly includes a first positioning part;

[0008] A housing that encloses the outside of the winding core assembly, with one end of the housing open;

[0009] A cap assembly is disposed at the opening of the housing. The cap assembly includes a top cover and a sealing ring. The top cover is located above the core assembly, and the sealing ring is located between the top cover and the housing to seal and insulate the top cover and the housing.

[0010] The top cover includes a second positioning part, which cooperates with the first positioning part to position and fix the core assembly.

[0011] As a preferred technical solution for a cylindrical lithium-ion battery, the top cover further includes an explosion-proof part, which is used to prevent the cylindrical lithium-ion battery from exploding.

[0012] As a preferred technical solution for a cylindrical lithium-ion battery, the top cover further includes a vent hole for discharging gas from inside the cylindrical lithium-ion battery.

[0013] As a preferred technical solution for a cylindrical lithium-ion battery, the second positioning part is a positioning through hole located in the middle of the top cover, and the first positioning part is a second positioning protrusion connected to the positioning through hole.

[0014] As a preferred technical solution for a cylindrical lithium-ion battery, the gap between the second positioning protrusion and the positioning through hole forms the vent hole.

[0015] As a preferred technical solution for a cylindrical lithium-ion battery, the second positioning part is a first positioning protrusion located in the middle of the top cover, the first positioning part is a second positioning protrusion, the top surface of the second positioning protrusion abuts against and is fixed to the top surface of the first positioning protrusion, and the vent hole is arranged around the second positioning part.

[0016] As a preferred technical solution for a cylindrical lithium-ion battery, the wound core assembly includes:

[0017] Core;

[0018] A positive electrode busbar is located at one end of the winding core and is connected to the positive electrode tab of the winding core;

[0019] The negative electrode busbar is located at the other end of the winding core and is connected to the negative electrode tab of the winding core;

[0020] The first positioning part is disposed on the positive electrode busbar or the negative electrode busbar.

[0021] As a preferred technical solution for a cylindrical lithium-ion battery, both the positive electrode tab and the negative electrode tab are integrally formed with the winding core.

[0022] As a preferred technical solution for a cylindrical lithium-ion battery, the surface where the positive electrode busbar connects to the positive electrode tab of the winding core is uneven.

[0023] The surface where the negative electrode busbar connects to the negative electrode tab of the winding core is uneven.

[0024] As a preferred technical solution for a cylindrical lithium-ion battery, the surface where the positive electrode busbar connects to the positive electrode tab is provided with a first spiral protrusion structure.

[0025] As a preferred technical solution for a cylindrical lithium-ion battery, the surface where the negative electrode busbar connects to the negative electrode tab is provided with a second spiral protrusion structure.

[0026] As a preferred technical solution for a cylindrical lithium-ion battery, the sealing ring includes a first insulating connection portion and a second insulating connection portion that are connected to each other. The first insulating connection portion is located between the upper surface of the top cover and the outer shell, and the second insulating connection portion is located between the lower surface of the top cover and the outer shell.

[0027] As a preferred technical solution for a cylindrical lithium-ion battery, the sealing ring further includes a shielding insulation portion connected to the second insulating connection portion;

[0028] The shielding insulation portion shields the space between the outer casing and the positive electrode busbar; or the shielding insulation portion shields the space between the outer casing and the negative electrode busbar.

[0029] This invention provides a cylindrical lithium-ion battery comprising a core assembly, a casing, and a cap assembly. The cap assembly includes a top cover and a sealing ring, reducing the number of parts in the cap assembly, simplifying the structure of the cylindrical lithium-ion battery, simplifying the processing steps, and reducing costs. The core assembly includes a first positioning part, and the top cover includes a second positioning part. The first and second positioning parts are connected to each other, thereby positioning and fixing the core assembly, reducing the risk of the tabs in the core assembly separating from the cap assembly, and improving battery safety. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the cylindrical lithium-ion battery provided in Embodiment 1 of the present invention;

[0031] Figure 2 This is a cross-sectional view of the cylindrical lithium-ion battery provided in Embodiment 1 of the present invention;

[0032] Figure 3 This is a schematic diagram of the positive electrode busbar provided in Embodiment 1 of the present invention;

[0033] Figure 4 This is a schematic diagram of the sealing ring provided in Embodiment 1 of the present invention;

[0034] Figure 5 This is a cross-sectional view of the sealing ring provided in Embodiment 1 of the present invention;

[0035] Figure 6 This is a partial structural diagram of the positive electrode foil after it has been cut at intervals according to Embodiment 1 of the present invention;

[0036] Figure 7 This is a cross-sectional view of the cylindrical lithium-ion battery according to Embodiment 2 of the present invention;

[0037] Figure 8 This is a first-view structural schematic diagram of the top cover provided in Embodiment 2 of the present invention;

[0038] Figure 9 This is a second-view structural schematic diagram of the top cover provided in Embodiment 2 of the present invention;

[0039] Figure 10 This is a first-view structural schematic diagram of the positive electrode busbar provided in Embodiment 2 of the present invention;

[0040] Figure 11 This is a schematic diagram of the positive electrode busbar provided in Embodiment 2 of the present invention from a second perspective.

[0041] Figure 12 This is a schematic diagram of the negative electrode busbar provided in Embodiment 2 of the present invention.

[0042] Figure label:

[0043] 1. Core assembly; 11. Core; 111. Positive electrode foil; 12. Positive electrode busbar; 121. First positioning part; 13. Negative electrode busbar;

[0044] 2. Outer shell;

[0045] 3. Cap assembly; 31. Top cover; 311. Second positioning part; 312. Explosion-proof part; 313. Vent hole; 32. Sealing ring; 321. First insulating connection part; 322. Second insulating connection part; 323. Shielding insulating part;

[0046] 4. Air pore sealing plug. Detailed Implementation

[0047] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0048] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0049] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0050] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0051] Example 1

[0052] like Figures 1-3 As shown, this embodiment provides a cylindrical lithium-ion battery, which includes a core assembly 1, a housing 2, and a cap assembly 3. The core assembly 1 includes a first positioning part 121. The housing 2 wraps around the core assembly 1, and one end of the housing 2 is open. The cap assembly 3 is disposed at the open end of the housing 2. The cap assembly 3 includes a top cover 31 and a sealing ring 32. The top cover 31 is located on the upper part of the core assembly 1, and the sealing ring 32 is located between the top cover 31 and the housing 2 to seal and insulate the top cover 31 and the housing 2. The top cover 31 includes a second positioning part 311, which cooperates with the first positioning part 121 to position and fix the core assembly 1.

[0053] The cap assembly 3 includes a top cover 31 and a sealing ring 32, reducing the number of parts in the cap assembly 3, simplifying the structure of the cylindrical lithium-ion battery, simplifying the processing steps, reducing costs, making reasonable use of space, and improving the functionality of the top cover 31. The core assembly 1 includes a first positioning part 121, and the top cover 31 includes a second positioning part 311. The first positioning part 121 and the second positioning part 311 are connected to each other, thereby positioning and fixing the core assembly 1, reducing the risk of the tabs in the core assembly 1 separating from the cap assembly 3, and improving battery safety. It should be noted that the external gas collection device can be any device capable of generating negative pressure and storing gas. Such devices are relatively conventional in the prior art, and their specific structures will not be described in detail here.

[0054] Preferably, the top cover 31 further includes an explosion-proof part 312 for explosion protection of the cylindrical lithium-ion battery. By integrating the explosion-proof function into the top cover 31, not only are the number of parts reduced, but the safe use of the cylindrical lithium-ion battery is also ensured.

[0055] Preferably, the top cover 31 further includes a vent 313 for discharging gas from inside the cylindrical lithium-ion battery. During the formation process, the gas is discharged through the vent 313 on the top cover 31. By connecting an external gas collection device to the vent 313, the gas generated during the formation process can be discharged and collected, thus avoiding environmental pollution and improving battery safety.

[0056] like Figure 2 As shown, in this embodiment, the second positioning part 311 is a positioning through hole located in the middle of the top cover 31, and the first positioning part 121 is a second positioning protrusion connected to the positioning through hole. The gap between the second positioning protrusion and the positioning through hole forms an exhaust hole 313. During the formation process, the exhaust hole 313 communicates with the outside to facilitate the discharge of gas. After the formation is completed, the exhaust hole 313 is sealed. The explosion-proof part 312 is arranged around the second positioning part 311.

[0057] Specifically, such as Figure 2 As shown, the core assembly 1 includes a core 11, a positive electrode busbar 12, and a negative electrode busbar 13. The positive electrode busbar 12 is located at one end of the core 11 and is connected to the positive electrode tab of the core 11; the negative electrode busbar 13 is located at the other end of the core 11 and is connected to the negative electrode tab of the core 11; a first positioning part 121 is disposed on the positive electrode busbar 12 or the negative electrode busbar 13. The connection method between the core 11 and the outer shell 2 is optimized. By designing the busbar structure, the electrode tab of the core 11 can be welded to the busbar without being flattened. On the one hand, this reduces the metal shavings generated by flattening; on the other hand, the gap between the electrode tabs in the upright state is larger than the size after flattening, which facilitates the electrolyte dispensing.

[0058] Preferably, in this embodiment, the first positioning part 121 is disposed on the positive electrode busbar 12. Further, the positive electrode busbar 12 includes a first positive electrode welding protrusion located in the center, and the first positioning part 121 is located on the first positive electrode welding protrusion. While the first positioning part 121 is positioned and connected to the second positioning part 311, the upper surface of the first positive electrode welding protrusion abuts against the top cover 31, and the first positive electrode welding protrusion is fixed to the top cover 31 by welding. In this embodiment, the explosion-proof part 312 is an annular region surrounding the welding area of ​​the top cover 31.

[0059] Preferably, both the positive and negative electrode tabs are integrally formed with the core 11. Specifically, the traditional electrode tab welding structure is eliminated. In this embodiment, one end of the positive electrode sheet has an uncoated positive electrode foil 111, and one end of the negative electrode sheet has an uncoated negative electrode foil. The positive and negative electrode foils are located at both ends of the core 11, and are formed before winding into the core 11. Figure 6 As shown, the positive electrode foil 111 and the negative electrode foil are cut at intervals to form positive and negative electrode tabs that are easy to be pressed down. The positive and negative electrode tabs lead out the current from the core 11. Since the positive and negative electrode tabs cannot concentrate the output current, the current is collected by connecting the positive electrode tabs to the positive electrode busbar 12 and the negative electrode busbar 13 respectively, and then output outward. The electrical connection method of the cylindrical lithium-ion battery is optimized, and the battery connection channels are reduced. Compared with the connection channels of traditional batteries: positive electrode foil, tabs, cover aluminum sheet, and nickel-plated steel cap, this embodiment only requires positive electrode foil 111, busbar, and top cover 31. The optimized effective contact area is increased, thereby improving the battery's current carrying capacity and reducing the battery's internal resistance.

[0060] Preferably, the height of both the positive and negative electrode tabs is 1mm to 3mm.

[0061] In this embodiment, both the positive and negative electrode tabs are connected to the positive busbar 12 and the negative busbar 13 by welding. Preferably, in this embodiment, to facilitate welding of the positive and negative electrode tabs to the positive busbar 12 and the negative busbar 13 respectively, the material of the positive busbar 12 is the same as the material of the positive electrode tab, and the material of the negative busbar 13 is the same as the material of the negative electrode tab.

[0062] like Figure 3 As shown, in this embodiment, the positive electrode busbar 12 includes two waist-shaped groove structures arranged in a ring, and the bottom surface of the waist-shaped groove structure is welded to the positive electrode tab.

[0063] Furthermore, the positive electrode busbar 12 is also provided with an overcurrent fuse. The overcurrent fuse is located between the welding area between the positive electrode tab and the positive electrode busbar 12 and the welding area between the positive electrode busbar 12 and the top cover 31. The thickness of the overcurrent fuse is thinner than the thickness of other parts of the positive electrode busbar 12, so as to ensure that the overcurrent fuse can disconnect in time when the current is abnormal.

[0064] The cylindrical lithium-ion battery also includes an insulating pad, which is disposed at the edge of the positive electrode busbar 12 to insulate the positive electrode busbar 12 from the outer casing 2. Preferably, to ensure that the position of the insulating pad does not move, the insulating pad is also wrapped with insulating tape, which can further ensure the position of the insulating pad while also ensuring the insulation between the positive electrode busbar 12 and the outer casing 2.

[0065] Preferably, the surface where the positive electrode busbar 12 connects to the positive electrode tab of the core 11 is uneven; the surface where the negative electrode busbar 13 connects to the negative electrode tab of the core 11 is also uneven. This makes the welding process between the positive and negative electrode tabs and the positive and negative electrode busbars 12 and 13 without secondary finishing, allowing for direct welding. This eliminates the need for the process of pressing and flattening the positive and negative electrode tabs to tilt them towards the center, making the processing simpler and more convenient. Furthermore, the uneven structure increases the effective contact area between the tabs and the busbars, ensuring the reliability of the connection between the tabs and the busbars.

[0066] Specifically, the surface of the positive electrode busbar 12 connected to the positive electrode tab is provided with a first spiral protrusion structure, and the positive electrode tab is connected to the positive electrode busbar 12 by laser welding from the outside to the inside of the outer shell 2. The surface of the negative electrode busbar 13 connected to the negative electrode tab is provided with a second spiral protrusion structure. It should be noted that the pitch of the first spiral protrusion structure and the second spiral protrusion structure can be designed and adjusted according to actual needs.

[0067] Preferably, in this embodiment, the first spiral protrusion structure on the positive electrode busbar 12 is mainly distributed in the area near the outer ring. Because the perimeter of the outer ring area of ​​the core 11 is longer, the total length of the positive electrode tab is longer, thereby increasing the effective area for connection between the first spiral protrusion structure and the positive electrode tab, ensuring the reliability of the connection between the positive electrode tab and the first spiral protrusion structure. In other embodiments, the connection area between the positive electrode busbar 12 and the positive electrode tab can be the middle area of ​​the positive electrode busbar 12 or the area near the outer ring, or the connection can be made in both locations.

[0068] Preferably, the circumferential edge of the negative electrode busbar 13 is provided with a vertical outer edge wall to prevent the negative electrode tab from protruding outward after being pressed.

[0069] like Figure 3 As shown, the positive electrode manifold 12 is also provided with multiple hollow areas to facilitate the external flow of gas and the liquid addition of electrolyte. The hollow areas are located in other areas of the first positioning part 121 and the welding area. The shape and specific location of the hollow areas will not be described here.

[0070] like Figure 4 and Figure 5As shown, the sealing ring 32 includes a first insulating connection portion 321 and a second insulating connection portion 322 that are interconnected. The first insulating connection portion 321 is located between the upper surface of the top cover 31 and the outer shell 2, and the second insulating connection portion 322 is located between the lower surface of the top cover 31 and the outer shell 2. After the cylindrical lithium-ion battery is sealed, the outer shell 2 is connected to the negative electrode tab of the core 11 through the negative electrode busbar 13, and the top cover 31 is connected to the positive electrode tab of the core 11 through the positive electrode busbar 12. By setting the sealing ring 32, the outer shell 2 is prevented from contacting the top cover 31 and short-circuiting when the top cover 31 is pressed and fixed.

[0071] Preferably, such as Figure 4 and Figure 5 As shown, the sealing ring 32 also includes a shielding insulation portion 323 connected to the second insulating connection portion 322; the shielding insulation portion 323 shields between the outer casing 2 and the positive electrode busbar 12; or the shielding insulation portion 323 shields between the outer casing 2 and the negative electrode busbar 13, ensuring that after the outer casing 2 is grooved between the top cover 31 and the positive electrode busbar 12 or the negative electrode busbar 13, the outer casing 2 will not come into contact with the positive electrode busbar 12 or the negative electrode busbar 13 and cause a short circuit. Preferably, in this embodiment, the shielding insulation portion 323 shields between the outer casing 2 and the positive electrode busbar 12.

[0072] In this embodiment, after the battery is sealed, the total height of the battery is compressed by mechanical pressure to ensure direct contact between the top cover 31 and the internal positive electrode busbar 12. Laser welding is performed around the central vent 313 area to weld the top cover 31 to the positive electrode busbar 12, and the central vent 313 is sealed to complete the final sealing of the battery. This process can be divided into two steps: the total height of the battery can be completed during the sealing process; after formation, the welding of the central area can be performed after the battery is formed and vented.

[0073] Example 2

[0074] like Figures 7-9 As shown, this embodiment also provides a cylindrical lithium-ion battery. Unlike the cylindrical lithium-ion battery in Embodiment 1, the second positioning portion 311 of the cylindrical lithium-ion battery in this embodiment is a first positioning protrusion located in the middle of the top cover 31, and the first positioning portion 121 is a second positioning protrusion. The top surface of the second positioning protrusion abuts against and is fixed to the top surface of the first positioning protrusion. The explosion-proof portion 312 and the vent 313 are arranged around the second positioning portion 311. In this embodiment, the cylindrical lithium-ion battery also includes a vent sealing plug 4, which is used to seal the vent 313.

[0075] like Figure 10 and Figure 11As shown, in this embodiment, the positive electrode busbar 12 includes four fan-shaped welding groove areas arranged in a circumferential direction, and multiple welding points are provided on the side of the four fan-shaped welding groove areas near the top cover 31, which facilitates subsequent welding and improves work efficiency.

[0076] like Figure 12 As shown, in this embodiment, the negative electrode busbar 13 includes an annular raised welding area, and multiple welding points are provided on the surface of the annular raised welding area facing away from the core 11, which facilitates subsequent welding and improves work efficiency.

[0077] Preferably, in this embodiment, all solder joints are circular solder joints.

[0078] The above description is only a preferred embodiment of the present invention. For those skilled in the art, there will be changes in the specific implementation and application scope based on the ideas of the present invention. The content of this specification should not be construed as a limitation of the present invention.

Claims

1. A cylindrical lithium-ion battery, characterized by, The application relates to a cylindrical lithium ion battery. The cylindrical lithium ion battery comprises: a winding core assembly (1) comprising a first positioning part (121); an outer shell (2) wrapped outside the winding core assembly (1), and one end of the outer shell (2) being open; a cap assembly (3) arranged at the open end of the outer shell (2), the cap assembly (3) comprising a top cover (31) located at the upper part of the winding core assembly (1) and a sealing ring (32) located between the top cover (31) and the outer shell (2) to seal and insulate the top cover (31) and the outer shell (2); the top cover (31) comprises a second positioning part (311) which is connected with the first positioning part (121) to position and fix the winding core assembly (1); the winding core assembly (1) comprises: a winding core (11); a positive busbar (12) located at one end of the winding core (11) and connected with positive tabs of the winding core (11); a negative busbar (13) located at the other end of the winding core (11) and connected with negative tabs of the winding core (11); the first positioning part (121) is arranged on the positive busbar (12) or the negative busbar (13); the positive tabs and the negative tabs are integrally arranged with the winding core (11); positive foil (111) and negative foil are arranged at two ends of the winding core (11), and the positive foil (111) and the negative foil are cut at intervals before being wound into the winding core (11) to form the positive tabs and the negative tabs which are easy to be pressed down; the top cover (31) further comprises an explosion-proof part (312) and an exhaust hole (313), the explosion-proof part (312) is used for explosion-proof of the cylindrical lithium ion battery, the explosion-proof part (312) is annularly arranged outside the second positioning part (311), the exhaust hole (313) is used for exhausting gas inside the cylindrical lithium ion battery, the second positioning part (311) is a positioning through hole located at the middle part of the top cover (31), the first positioning part (121) is a second positioning protrusion, the second positioning protrusion is connected in the positioning through hole, and a gap between the second positioning protrusion and the positioning through hole forms the exhaust hole (313); 2. The cylindrical lithium-ion battery of claim 1, wherein, alternatively, the second positioning part (311) is a first positioning protrusion located at the middle part of the top cover (31), and the first positioning part (121) is a second positioning protrusion, and the top surface of the second positioning protrusion abuts and is fixed to the top surface of the first positioning protrusion. the surface of the positive busbar (12) connected with the positive tabs of the winding core (11) is uneven; 3. The cylindrical lithium-ion battery of claim 2, wherein, the surface of the negative busbar (13) connected with the negative tabs of the winding core (11) is uneven.

4. The cylindrical lithium-ion battery of claim 2, wherein, the surface of the positive busbar (12) connected with the positive tabs is provided with a first spiral protrusion structure. the surface of the negative busbar (13) connected with the negative tabs is provided with a second spiral protrusion structure.

5. The cylindrical lithium-ion battery of claim 1, wherein, The sealing ring (32) comprises a first insulation connecting part (321) and a second insulation connecting part (322) connected with each other, the first insulation connecting part (321) is located between the upper surface of the top cover (31) and the shell (2), and the second insulation connecting part (322) is located between the lower surface of the top cover (31) and the shell (2).

6. The cylindrical lithium-ion battery of claim 5, wherein, The sealing ring (32) further comprises a shielding insulation part (323) connected with the second insulation connecting part (322). The shielding insulation part (323) is shielded between the shell (2) and the positive bus bar (12), or the shielding insulation part (323) is shielded between the shell (2) and the negative bus bar (13).

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