Cylindrical battery and battery pack

Abstract

The utility model belongs to the technical field of batteries, and discloses a cylindrical battery and a battery pack. The cylindrical battery comprises a shell and a pole group. Wherein the shell is provided with a first end part and a second end part which are oppositely arranged, and the first end part is provided with a positive terminal in an insulated and sealed manner; a positive pole lug and a negative pole lug are respectively arranged at two opposite ends of the pole group, the positive pole lug is contacted and fixedly connected with the positive terminal, and the negative pole lug is contacted and fixedly connected with the second end part. According to the arrangement, structural parts and corresponding assembling and welding steps are reduced, the manufacturing cost is reduced, and the assembling efficiency of the cylindrical battery is improved; and the positive electrode connection space and the negative electrode connection space of the cylindrical battery are saved, and the volume of the pole group of the cylindrical battery is increased, so that the volume utilization rate and the energy density of the cylindrical battery are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and in particular to a cylindrical battery and a battery pack. Background Art

[0002] With the rapid development of the electric vehicle industry, the demand for high-energy-density and high-safety lithium-ion batteries is increasing. Large cylindrical power batteries have great advantages in adapting to different chemical systems, and therefore have developed rapidly.

[0003] For large cylindrical batteries, high-nickel systems are often used to compensate for the low module efficiency. However, the use of high-nickel materials is accompanied by an increased risk of thermal runaway, which affects the safety of the battery. Therefore, medium-nickel high-voltage systems have been introduced. In addition, at present, large cylindrical battery cells mainly lead out the tabs at both ends of the electrode group, flatten the tabs, and then weld the positive and negative tabs to the positive and negative electrode covers through current collecting plates at both ends to achieve external connection of the tabs. This arrangement will result in more structures in the positive and negative electrical connection areas of the battery, occupying a larger space, thereby reducing the battery space utilization rate, resulting in lower volume energy density, and more process steps, affecting production efficiency.

[0004] Therefore, there is an urgent need for a cylindrical battery and a battery pack to solve the above technical problems. Utility Model Content

[0005] One purpose of the present utility model is to provide a cylindrical battery and a battery pack, which can improve the volume utilization and energy density of the cylindrical battery, save the time and cost of structure and part of the process assembly, and improve production efficiency.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] Cylindrical batteries, including:

[0008] A housing having a first end and a second end opposite to each other, wherein the first end is insulated and sealed with a positive terminal;

[0009] The electrode group comprises a positive electrode tab and a negative electrode tab at two opposite ends of the electrode group, wherein the positive electrode tab contacts and is fixedly connected to the positive electrode terminal, and the negative electrode tab contacts and is fixedly connected to the second end.

[0010] Optionally, a groove is provided on a side of the positive terminal facing the electrode group, and the positive electrode tab can be disposed in the groove and fixedly connected to the positive terminal.

[0011] Optionally, the depth of the groove is not greater than the height of the positive electrode tab.

[0012] Optionally, a through hole is formed at the first end portion, the positive terminal is disposed in the through hole, and an insulating seal is clamped between the positive terminal and the wall of the through hole.

[0013] Optionally, the positive terminal and the positive electrode tab are connected by laser penetration welding; and / or,

[0014] The shell and the negative electrode tab are connected by pulse laser welding.

[0015] Optionally, the above-mentioned electrode group is a lithium nickel cobalt manganese oxide-graphite chemical system core.

[0016] Optionally, both the inner surface of the shell and the outer surface of the shell are provided with a nickel plating layer.

[0017] Optionally, the positive terminal is provided with an insulating member near the outer peripheral wall of the electrode group, the inner peripheral wall of the insulating member is connected to the outer peripheral wall of the positive terminal, and the outer peripheral wall of the insulating member is close to the inner peripheral wall of the outer shell to insulate the connection area between the positive terminal and the positive electrode ear from the outer shell.

[0018] Optionally, along the direction from the inner peripheral wall to the outer peripheral wall of the insulating member, the insulating member is arranged away from the first end portion.

[0019] Another object of the present invention is to provide a battery pack, comprising the cylindrical battery described in any of the above schemes, which can improve the volume utilization and energy density of the battery pack.

[0020] Beneficial effects of the utility model:

[0021] The present invention provides a cylindrical battery and battery pack that eliminates the positive and negative current collector plates, allowing the positive electrode tab to connect directly to the positive terminal at the first end of the outer shell, and the negative electrode tab to connect directly to the second end of the outer shell. This achieves the characteristic that the positive terminal of the cylindrical battery serves as the positive electrode external output terminal, and the outer shell serves as the negative electrode external output terminal. This arrangement not only reduces the number of structural components and the corresponding assembly and welding steps, lowering manufacturing costs and improving the assembly efficiency of the cylindrical battery, but also saves space for the positive and negative electrode connections of the cylindrical battery, increasing the volume of the cylindrical battery's electrode group, thereby improving the volume utilization and energy density of the cylindrical battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural diagram of a cylindrical battery provided by a specific embodiment of the utility model;

[0023] Figure 2 It is a structural schematic diagram of the positive electrode sheet provided by a specific embodiment of the present utility model.

[0024] In the picture:

[0025] 10. Housing; 11. Positive terminal; 111. Groove; 112. Overlapping portion; 12. Housing; 121. Opening; 13. End cap; 131. Liquid injection hole; 14. Insulating seal; 15. Rubber plug; 16. Sealing sheet;

[0026] 20. Electrode group; 201. Positive electrode sheet; 21. Positive electrode tab; 22. Negative electrode tab; 23. Hollow cavity;

[0027] 30. Insulation parts. DETAILED DESCRIPTION

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are intended only to illustrate the present invention and are not intended to limit the present invention. It should also be noted that, for ease of description, the accompanying drawings only illustrate portions relevant to the present invention, not all of its components.

[0029] In the description of this utility model, unless otherwise specified or limited, the terms "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; they can refer to direct connection or indirect connection through an intermediate medium; they can refer to internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0030] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0031] In the description of this embodiment, the terms "upper," "lower," "left," "right," and other orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely for ease of description and simplified operation. They do not indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first" and "second" are used solely for descriptive purposes and have no special meaning.

[0032] Please refer to the attached Figure 1 and attached Figure 2 The utility model introduces a cylindrical battery and a battery pack.

[0033] Please refer to Figure 1 This embodiment provides a cylindrical battery comprising a housing 10 and an electrode group 20. The housing 10 has a first end and a second end disposed opposite each other. The first end is provided with a positive electrode terminal 11 in an insulated and sealed manner. A positive electrode tab 21 and a negative electrode tab 22 are provided at opposite ends of the electrode group 20, respectively. The positive electrode tab 21 contacts and is fixedly connected to the positive electrode terminal 11, while the negative electrode tab 22 contacts and is fixedly connected to the second end.

[0034] The cylindrical battery in this embodiment eliminates the positive and negative current collector plates, allowing the positive electrode tab 21 to connect directly to the positive terminal 11 at the first end of the outer shell 10, and the negative electrode tab 22 to connect directly to the second end of the outer shell 10. This allows the positive terminal 11 of the cylindrical battery to function as the positive electrode output terminal, while the outer shell 12 functions as the negative electrode output terminal. This arrangement not only reduces the number of structural components and the corresponding assembly and welding steps, lowering manufacturing costs and improving the assembly efficiency of the cylindrical battery, but also saves space for the positive and negative electrode connections, increasing the volume of the electrode group 20 of the cylindrical battery, thereby improving the volume utilization and energy density of the cylindrical battery.

[0035] Please refer to Figure 1 In some embodiments, the housing 10 includes a shell 12 and a cover plate. The first end of the shell 12 is insulated and sealed with a positive terminal 11, and the second end is provided with an opening 121 for installing the electrode group 20. The cover plate is sealed and connected to the opening 121. During installation, the end of the electrode group 20 with the positive electrode tab 21 is installed in the shell 12 through the opening 121. Then, the positive electrode tab 21 and the positive terminal 11 are electrically connected. The cover plate is then sealed and connected to the shell 12, and the negative electrode tab 22 is electrically connected to the cover plate. Finally, the corresponding electrolyte is injected to complete the installation of the cylindrical battery.

[0036] Specifically, a liquid injection hole 131 is opened on the end cover 13, and the electrolyte can be injected into the housing 10 through the liquid injection hole 131 to achieve the injection of the electrolyte.

[0037] More specifically, the injection hole 131 is sealed with a rubber plug 15 to plug and seal the injection hole 131 after the cylindrical battery is injected. A sealing sheet 16 is also provided outside the injection hole 131 to seal the injection hole 131 and the rubber plug 15, thereby ensuring better sealing of the housing 10.

[0038] Optionally, the sealing sheet 16 and the end cover 13 are connected by laser welding, which has a good welding effect.

[0039] Optionally, both the inner surface of the housing 10 and the outer surface of the housing 10 are provided with a nickel plating layer to improve wear resistance, electrical conductivity and corrosion resistance.

[0040] For example, the thickness of the housing 10 is 0.3 mm to 0.5 mm, and the thickness of the nickel plating layer is 4 μm to 8 μm, which is a preferred range.

[0041] In some embodiments, a through hole is opened at the first end, the positive terminal 11 is arranged in the through hole, and an insulating seal 14 is clamped between the positive terminal 11 and the hole wall of the through hole. The insulating seal 14 can realize the insulating and sealed connection between the positive terminal 11 and the outer shell 10.

[0042] In some embodiments, an insulating member 30 is provided on the outer peripheral wall of the positive terminal 11 near the electrode group 20, and the inner peripheral wall of the insulating member 30 is connected to the outer peripheral wall of the positive terminal 11, and the outer peripheral wall of the insulating member 30 is close to the inner peripheral wall of the outer shell 10 to insulate the connection area between the positive terminal 11 and the positive electrode tab 21 from the outer shell 10.

[0043] Specifically, a lap portion 112 is provided on the outer periphery of the positive terminal 11 on a side close to the electrode group 20 , and the lap portion 112 is used to support the annular insulating member 30 .

[0044] Optionally, the insulating member 30 and the insulating seal 14 are arranged in contact with each other so that the outer periphery of the positive terminal 11 is provided with an insulating structure, thereby improving the insulation effect of the positive electrode connection area, thereby improving the safety of the cylindrical battery.

[0045] Specifically, along the direction from the inner circumferential wall to the outer circumferential wall of the insulating member 30, the insulating member 30 is arranged away from the first end. This arrangement makes the insulating member 30 have an inclination angle, so that the electrolyte inside the shell 10 will not be retained at the insulating member 30 after contacting the insulating member 30, causing corrosion of the shell 12 near the insulating member 30, that is, the electrolyte can flow back into the shell 10 through the inclination angle, thereby improving the service life of the cylindrical battery.

[0046] Optionally, the insulating member 30 includes a planar portion and an inclined portion, and the inclined portion is arranged on the periphery of the planar portion, so that the insulating member 30 is arranged away from the first end along the direction from the inner peripheral wall to the outer peripheral wall of the insulating member 30.

[0047] Optionally, the insulating member 30 is arranged gradually away from the first end portion along the direction from the inner peripheral wall to the outer peripheral wall of the insulating member 30. Such an arrangement has a certain smoothness and avoids dead corners that cause accumulation of electrolyte.

[0048] In some embodiments, a groove 111 is provided on the side of the positive terminal 11 facing the electrode group 20, and the positive electrode tab 21 can be arranged in the groove 111 and fixedly connected to the positive terminal 11 to increase the connection area between the positive terminal 11 and the positive electrode tab 21, thereby improving the fixing effect of the two.

[0049] Optionally, the depth of the groove 111 is not greater than the height of the positive electrode tab 21 , ensuring that the positive electrode terminal 11 is not directly connected to the main body of the electrode group 20 to avoid problems such as short circuits.

[0050] Optionally, the outer diameter of the positive terminal 11 is 28±0.5 mm, and the diameter of the positive electrode tab 21 is 26±0.5 mm, so that the positive electrode tab 21 can be fully contacted and connected with the positive terminal 11 .

[0051] Specifically, the positive terminal 11 and the positive electrode tab 21 , as well as the housing 10 and the negative electrode tab 22 , are fixedly connected by welding, which has a good fixing effect and good sealing performance.

[0052] Optionally, the positive terminal 11 and the positive electrode tab 21 are welded together by a laser penetration welding process; and / or, the shell 10 and the negative electrode tab 22 are welded together by a pulsed laser welding process, so as to better achieve fixed connection at each position and better welding effect.

[0053] In some embodiments, the electrode group 20 is a core of a lithium nickel cobalt manganese oxide-graphite chemical system, that is, a core of a medium nickel high voltage system.

[0054] Specifically, the electrode assembly 20 is formed by stacking the separator, the positive electrode sheet 201, the separator, the negative electrode sheet, and the separator from the inside out, and then winding. The joint at the center of the wound electrode assembly 20 is the winding core, and the joint at the periphery of the wound electrode assembly 20 is the winding tail.

[0055] Optionally, the interior of the electrode group 20 is hollowed to form a hollow cavity 23 to facilitate subsequent welding, liquid injection and exhaust.

[0056] Please refer to Figure 2 Alternatively, the positive electrode tab 21 is formed by cutting excess portions through a die-cutting process, and then winding and flattening processes are performed to form the positive electrode tab 21, so that the positive electrode tab 21 is located near the center of the electrode assembly 20, thereby preventing the positive electrode tab 21 from being too close to the housing 12 and causing a short circuit. The negative electrode tab is directly formed through the winding and flattening process.

[0057] Optionally, the positive electrode tab 21 is arranged at a position of the positive electrode sheet 201 close to the winding core, that is, the positive electrode tab 21 at a position of the positive electrode sheet 201 close to the winding end is cut so that the positive electrode tab 21 is located near the center of the electrode group 20.

[0058] Specifically, the positive electrode sheet 201 comprises an aluminum foil layer and a positive electrode coating layer. The aluminum foil layer serves as a base material, and the positive electrode coating layer is made of lithium nickel cobalt manganese oxide as the active material, multi-walled carbon nanotubes and SP as conductive agents, and polyvinylidene fluoride as a binder. The negative electrode sheet comprises a copper foil layer and a negative electrode coating layer. The copper foil layer serves as a base material, and the negative electrode coating layer is made of artificial graphite and silicon as the active ingredients, SP as a conductive additive, and PAA + CMC as a binder. The separator comprises a nanoboehmite coating and a polyethylene film to enhance its insulation performance.

[0059] Optionally, the single-sided density of the positive electrode coating layer is 130 g / m 2 -160g / m 2 , the thickness of the aluminum foil layer is 8μm-14μm, which is the commonly used optional range.

[0060] Furthermore, the single-sided density of the negative electrode coating layer is 70 g / m 2 -90g / m 2 The thickness of the copper foil layer is 6μm-12μm, which is a commonly used optional range.

[0061] Specifically, the coating thickness of the separator is 3 μm-5 μm, and the thickness of the polyethylene-based film is 8 μm-12 μm, which is a commonly used optional range.

[0062] This embodiment further provides a battery pack comprising the cylindrical battery described in any of the above solutions. The battery pack uses the above cylindrical battery, thereby improving the energy density and volume utilization of the battery pack.

[0063] Obviously, the above-described embodiments of the present invention are merely examples for the purpose of clearly illustrating the present invention and are not intended to limit the manner in which the present invention is to be implemented. A person skilled in the art would be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is not necessary and impossible to enumerate all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. Cylindrical battery, characterized in that, include: a housing having a first end and a second end opposite to each other, wherein the first end is insulated and sealed with a positive terminal; An electrode group, wherein two opposite ends of the electrode group are respectively provided with a positive electrode tab and a negative electrode tab, the positive electrode tab is in contact with and fixedly connected to the positive electrode terminal, and the negative electrode tab is in contact with and fixedly connected to the second end.

2. The cylindrical battery according to claim 1, characterized in that: A groove is provided on a side of the positive terminal facing the electrode group, and the positive electrode tab can be disposed in the groove and fixedly connected to the positive terminal.

3. The cylindrical battery according to claim 2, characterized in that: The depth of the groove is no greater than the height of the positive electrode tab.

4. The cylindrical battery according to claim 1, characterized in that A through hole is formed at the first end portion, the positive terminal is arranged in the through hole, and an insulating seal is clamped between the positive terminal and the hole wall of the through hole.

5. The cylindrical battery according to claim 1, characterized in that: The positive terminal and the positive electrode tab are connected by laser penetration welding; and / or, The shell and the negative electrode tab are welded together by a pulse laser welding process.

6. The cylindrical battery according to claim 1, characterized in that The electrode group is a lithium nickel cobalt manganese oxide-graphite chemical system winding core.

7. The cylindrical battery according to claim 1, characterized in that: The inner surface of the shell and the outer surface of the shell are both provided with a nickel plating layer.

8. The cylindrical battery according to any one of claims 1 to 7, characterized in that: The positive terminal is provided with an insulating member near the outer peripheral wall of the electrode group, the inner peripheral wall of the insulating member is connected to the outer peripheral wall of the positive terminal, and the outer peripheral wall of the insulating member is close to the inner peripheral wall of the outer shell to insulate the connection area between the positive terminal and the positive electrode tab from the outer shell.

9. The cylindrical battery according to claim 8, characterized in that: Along the direction from the inner peripheral wall to the outer peripheral wall of the insulating member, the insulating member is arranged away from the first end portion.

10. A battery pack, characterized in that: The invention comprises a cylindrical battery as claimed in any one of claims 1 to 9.

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