Cylindrical battery monomer, battery and power utilization device

Abstract

The embodiment of the utility model provides a cylindrical battery monomer, a battery and a power utilization device. The cylindrical battery cell includes a housing, a first electrode lead-out portion, an electrode assembly, and a current collecting member. The first electrode lead-out part is arranged on the housing. The electrode assembly is accommodated in the housing and includes an electrode main body and a first tab led out from an end portion of the electrode main body. The current collecting component is electrically connected to the first electrode lead-out part, the current collecting component is welded to the first tab and forms a plurality of welding printing groups, and the plurality of welding printing groups are arranged at intervals in the circumferential direction of the current collecting component. Each welding mark group comprises a first welding mark and a second welding mark, the first welding mark is provided with a first end close to the central axis and a second end far away from the central axis in the direction, pointing to the central axis of the electrode assembly, of the exterior of the electrode assembly, and the second welding mark is provided with a third end close to the central axis and a fourth end far away from the central axis. The extension length of the first welding mark is larger than that of the second welding mark, and the distance between the third end and the second end is smaller than that between the third end and the first end.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and more particularly, to a cylindrical battery cell, a battery, and an electrical device. Background Art

[0002] Battery cells, especially cylindrical battery cells, are widely used in electronic devices such as mobile phones, laptop computers, battery cars, electric vehicles, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and electric tools, etc.

[0003] In the development of battery technology, how to improve the reliability of cylindrical battery cells is a research direction in battery technology. Summary of the Utility Model

[0004] The present application provides a cylindrical battery cell, a battery, and an electrical device, which can improve reliability.

[0005] In a first aspect, an embodiment of the present application provides a cylindrical battery cell, which includes a housing, a first electrode lead-out portion, an electrode assembly, and a current collector member. The first electrode lead-out portion is disposed on the housing. The electrode assembly is accommodated in the housing. The electrode assembly is of a wound structure and includes an electrode body and a first tab led out from an end of the electrode body. The current collector member is electrically connected to the first electrode lead-out portion. The current collector member is located on a side of the first tab away from the electrode body. The current collector member is welded to the first tab and forms a plurality of weld mark groups, and the plurality of weld mark groups are arranged at intervals along the circumference of the current collector member. Each weld mark group includes at least one first weld mark and at least one second weld mark. In a direction from the outside of the electrode assembly towards the central axis of the electrode assembly, the first weld mark and the second weld mark extend linearly. The first weld mark has a first end close to the central axis and a second end away from the central axis. The second weld mark has a third end close to the central axis and a fourth end away from the central axis. The extension length of the first weld mark is greater than the extension length of the second weld mark, and the distance between the third end and the second end is less than the distance between the third end and the first end.

[0006] The first weld mark has a larger extension length, which can transmit the current of the part of the first tab close to the central axis and the current of the part of the first tab away from the central axis at the same time. The circumference of the part of the first tab away from the central axis is larger, and the requirement for the current-carrying area is also higher. The second weld mark is disposed relatively outside with respect to the first end, and it can jointly transmit the current of the part of the first tab away from the central axis with the first weld mark, thereby improving the current-carrying capacity, reducing the temperature rise, improving the fast-charging ability of the battery cell, and improving the cycle performance and reliability of the battery cell.

[0007] The farther away from the central axis, the larger the circumferential dimension of the first tab and the current collector member. By arranging the second weld mark with a smaller extension length towards the outside, the distance between the first weld mark and the second weld mark can be increased, thereby reducing heat accumulation during the welding process, lowering the temperature rise, and improving reliability. The circumference of the part of the first tab close to the central axis is smaller, and its distance from the first end is relatively close. Therefore, the part of the first tab close to the central axis has a lower requirement for the current-carrying area, and the second weld mark can be shortened to reduce the heat generated during welding, simplify the welding process, and improve reliability.

[0008] In the embodiment of the present application, by adopting two first weld marks and second weld marks with different extension lengths, and arranging the second weld mark in the outer region of the first tab, the current-carrying area between the current collector member and the tab is increased, and heat accumulation is reduced during the formation of the weld mark, the temperature rise is lowered, and the reliability and cycle performance of the battery cell are improved.

[0009] In some embodiments, both the first weld mark and the second weld mark extend along a straight line. Adopting the straight-line first weld mark and second weld mark can simplify the welding process and reduce the assembly difficulty of the battery cell.

[0010] In some embodiments, the first weld mark extends along the radial direction of the current collector member; and / or, the second weld mark extends along the radial direction of the current collector member. On the premise of a certain extension length, setting the first weld mark to extend along the radial direction of the current collector member and setting the second weld mark to extend along the radial direction of the current collector member can both improve the current-carrying capacity between the current collector member and the first tab.

[0011] In some embodiments, the weld mark group includes two first weld marks. By setting two first weld marks, the current-carrying capacity between the current collector member and the first tab can be further improved. By increasing the number of first weld marks in the weld mark group, the requirement for the number of weld mark groups can be reduced.

[0012] In some embodiments, in the circumferential direction of the current collector member, the third end is located between two adjacent first weld marks. Utilizing the space between the two first weld marks to set the second weld mark can improve the space utilization rate. Compared with the scheme of setting the second weld mark outside the two first weld marks, the embodiment of the present application can increase the distance between the two first weld marks, reduce heat accumulation, and reduce the risk of repeated welding.

[0013] In some embodiments, in the circumferential direction of the current collector member, the fourth end is located between two adjacent first weld marks. During the welding process of the current collector member and the first tab, the fourth end of the second weld mark can use the second end of the first weld mark as a reference, thereby reducing the risk of welding outside the current collector member and improving reliability.

[0014] In some embodiments, the weld mark group further includes a third weld mark that connects the first ends of two first weld marks. The third end is spaced apart from the third weld mark. The two first weld marks and the third weld mark are integrated, which can increase the current-carrying area and reduce the temperature rise of the battery cell during cycling. Compared with the solution of forming two first weld marks in two welding processes, the embodiments of the present application can complete the two first weld marks and the third weld mark in one welding process, thereby reducing the risk of welding explosion points and improving the welding efficiency.

[0015] In some embodiments, at least a part of the third weld mark is arc-shaped. The arc shape can make the change of the welding direction smoother, reduce the risk of welding explosion points, and improve the welding quality.

[0016] In some embodiments, the first weld mark extends along the radial direction of the current collector member. The current collector member includes a first sector area and a second sector area. In the circumferential direction of the current collector member, the first sector area is located between the two first weld marks of the weld mark group, and the second sector area is located between adjacent weld mark groups. The central angle of the second sector area is greater than the central angle of the first sector area.

[0017] When welding the current collector member and the first tab, an external device can abut against the second sector area and press the current collector member tightly against the first tab to make the current collector member fit with the first tab during the welding process, reducing the risk of poor welding. The second sector area has a larger area, which can increase the pressed area of the current collector member and improve the welding stability.

[0018] In some embodiments, the ratio of the extension length L2 of the second weld mark to the extension length L1 of the first weld mark is 0.1 - 0.5. Limiting L2 / L1 to be greater than or equal to 0.1 can improve the current-carrying capacity of the second weld mark and reduce the temperature rise of the battery cell during cycling. Limiting L2 / L1 to be less than or equal to 0.5 can make the minimum distance between the second weld mark and the first weld mark meet the requirements.

[0019] In some embodiments, the minimum distance between the fourth end and the central axis is less than or equal to the minimum distance between the second end and the central axis. During the process of welding the current collector member and the first tab, the fourth end of the second weld mark can be based on the second end of the first weld mark, thereby reducing the risk of welding outside the current collector member and improving the reliability.

[0020] In some embodiments, in the circumferential direction of the current collector member, the maximum distance between adjacent weld mark groups is greater than the maximum size of the weld mark group. The adjacent weld mark groups are spaced apart by a relatively large distance. In other words, in addition to the area to be welded, the current collector member also has a relatively large area that can be pressed by an external device; when welding the current collector member and the first tab, the external device can press the current collector member tightly against the first tab to make the current collector member fit with the first tab during the welding process, reducing the risk of poor welding.

[0021] In some embodiments, a plurality of recesses are provided on a side of the current collector member facing away from the first tab, and the plurality of recesses are arranged at intervals along the circumferential direction of the current collector member. The bottom wall of each recess is welded to the first tab to form a set of welding imprints. During welding, the recesses can be used for positioning, facilitating the welding equipment to capture the welding position and improving the welding efficiency. An external device can press against the non-recessed area of the current collector member to make the current collector member fit with the first tab during the welding process, reducing the risk of false soldering.

[0022] In some embodiments, at least a part of the first electrode lead-out portion is located on a side of the current collector member facing away from the first tab and abuts against the current collector member. A plurality of sets of welding imprints are arranged along the outer circumference of the first electrode lead-out portion, and each set of welding imprints is spaced apart from the first electrode lead-out portion. Due to welding process reasons, the flatness of the set of welding imprints is poor; in the embodiments of the present application, the set of welding imprints is arranged to avoid the first electrode lead-out portion, so that the current collector member can fit with the first electrode lead-out portion, improving the stability of the connection between the current collector member and the first electrode lead-out portion.

[0023] In some embodiments, the width W2 of the second welding imprint is 0.5 times to 2 times the width W1 of the first welding imprint. Limiting W2 / W1 to be greater than or equal to 0.5 can enable the second welding imprint to have a relatively large current-carrying area, reducing the temperature rise of the battery cell during cycling. Limiting W2 / W1 to be less than or equal to 2 can save the space occupied by the second welding imprint in the circumferential direction of the current collector member, increase the minimum distance between the second welding imprint and the first welding imprint, reduce heat accumulation during welding, and improve reliability.

[0024] In some embodiments, the minimum distance D1 between the third end and the first welding imprint is greater than or equal to 0.5 times the width W1 of the first welding imprint. During welding, the width W1 of the first welding imprint is related to the welding power and the heat generated during welding. In the embodiments of the present application, D1 / W1 is limited to be greater than or equal to 0.5 to reduce heat accumulation during welding, reduce the risk of the first welding imprint and the second welding imprint joining and causing explosion points, and improve reliability.

[0025] In some embodiments, the first tab is wound to form N winding turns, and the second welding imprint is connected to M winding turns, where 0.05 ≤ M / N ≤ 0.4.

[0026] Limiting M / N to be greater than or equal to 0.05 can enable the second welding imprint to connect more winding turns, increasing the current-carrying area between the winding turns far from the central axis and the current collector member, enhancing the current-carrying capacity, reducing the temperature rise, and improving the cycling performance of the battery cell. Limiting M / N to be less than or equal to 0.4 can increase the distance between the third end and the central axis and the distance between the third end and the first end, reduce heat accumulation during welding, and improve reliability.

[0027] In some embodiments, the outer casing includes a wall portion, and the first electrode lead-out portion is an electrode terminal that is insulatingly disposed on the wall portion; alternatively, the outer casing includes a housing and an end cap, the housing has an opening, the end cap is closed on the opening, and the first electrode lead-out portion is at least a part of one of the housing and the end cap.

[0028] In some embodiments, the current collector member is provided with a channel that penetrates the current collector member along the thickness direction of the current collector member. In the circumferential direction of the current collector member, at least a part of the channel is located between adjacent welding mark groups. When the battery cell experiences thermal runaway accidentally, the substances generated by the reaction of the electrode assembly can pass through the current collector member via the channel, so as to be discharged to the outside of the outer casing in time and reduce the explosion risk. By using the part of the current collector member located between the welding mark groups to form the channel, the current-carrying capacity and the exhaust capacity of the current collector member can be taken into account.

[0029] In some embodiments, the height of the outer casing is 1.3 times to 4 times the diameter of the outer casing.

[0030] In some embodiments, the height of the outer casing is 50 mm to 150 mm.

[0031] In some embodiments, the diameter of the outer casing is 40 mm to 80 mm.

[0032] In a second aspect, embodiments of the present application provide a battery, which includes a plurality of cylindrical battery cells provided in any one of the embodiments of the first aspect.

[0033] In a third aspect, embodiments of the present application provide an electrical device, which includes the battery provided in any one of the embodiments of the second aspect, and the battery is used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required to be used in the embodiments of the present application. Obviously, the following described drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained according to the drawings without creative efforts.

[0035] Figure 1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application;

[0036] Figure 2 is a schematic explosion diagram of a battery provided in some embodiments of the present application;

[0037] Figure 3 is Figure 2 a schematic structural diagram of the battery module shown;

[0038] Figure 4 is a schematic structural diagram of a cylindrical battery cell provided in some embodiments of the present application;

[0039] Figure 5 is Figure 4 the explosion schematic diagram of the cylindrical battery cell shown;

[0040] Figure 6 is Figure 4 the cross-sectional schematic diagram of the cylindrical battery cell shown;

[0041] Figure 7 is the schematic diagram of the electrode assembly of the cylindrical battery cell provided by some embodiments of the present application;

[0042] Figure 8 is the schematic diagram of the electrode assembly and the current collector member of the cylindrical battery cell provided by some embodiments of the present application after welding;

[0043] Figure 9 is Figure 6 the enlarged schematic diagram at the round frame;

[0044] Figure 10 is the schematic diagram of the electrode assembly and the current collector member provided by some other embodiments of the present application;

[0045] Figure 11 is the schematic diagram of the electrode assembly and the current collector member provided by some other embodiments of the present application;

[0046] Figure 12 is Figure 11 the cross-sectional schematic diagram made along the A-A direction;

[0047] Figure 13 is Figure 12 the enlarged schematic diagram at the round frame;

[0048] Figure 14 is the schematic diagram of the electrode assembly and the current collector member provided by some embodiments of the present application.

[0049] The description of the reference numerals is as follows:

[0050] 1, vehicle; 2, battery; 3, controller; 4, motor; 5, box body; 5a, first box body part; 5b, second box body part; 5c, accommodation space; 6, battery module; 7, cylindrical battery cell; 7a, first electrode lead-out part; 7b, second electrode lead-out part;

[0051] 10, electrode assembly; 11, electrode main body; 12, first tab; 13, second tab;

[0052] 20, outer shell; 21, housing; 211, end wall; 212, side wall; 22, end cover;

[0053] 30, electrode terminal; 31, terminal main body; 311, terminal recess; 32, cover plate;

[0054] 40. Current collecting member; 41. First sector area; 42. Second sector area; 43. Concave portion; 44. Convex portion; 45. Channel; 451. Linear channel; 452. First hole; 453. Second hole;

[0055] 50. Weld mark group; 51. First weld mark; 511. First end; 512. Second end; 52. Second weld mark; 521. Third end; 522. Fourth end; 53. Third weld mark; C. Central axis;

[0056] V. Circumferential direction; X. Winding direction; Z. Axial direction. Detailed implementation manners

[0057] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some but not all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0058] Unless otherwise defined, all technical and scientific terms used in the present application have the same meanings as those commonly understood by those of ordinary skill in the technical field to which the present application belongs; the terms used in the description of the present application in the specification are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "including" and "having" and any variations thereof in the description and claims of the present application and the above drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the description and claims of the present application or the above drawings are used to distinguish different objects and are not used to describe a specific order or primary-secondary relationship.

[0059] Referring to "embodiments" in the present application means that specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears in various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments.

[0060] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0061] In this application, the term "and / or" is merely a description of the association relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, in this application, the character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0062] In the embodiments of this application, the same reference numerals represent the same components. And for the sake of brevity, in different embodiments, the detailed description of the same components is omitted. It should be understood that the thickness, length, width, etc. of various components shown in the drawings in the embodiments of this application, as well as the overall thickness, length, width, etc. of the integrated device, are only for illustrative purposes and should not constitute any limitation to this application.

[0063] The term "a plurality of" as used in this application refers to two or more (including two).

[0064] The cylindrical battery cell can be a secondary battery, and a secondary battery refers to a battery cell that can be activated by charging after discharging to continue to be used.

[0065] A battery can refer to a single physical module including one or more cylindrical battery cells to provide a higher voltage and capacity.

[0066] Generally, a cylindrical battery cell includes an electrode assembly. The electrode assembly includes a positive electrode and a negative electrode. During the charging and discharging process of the cylindrical battery cell, active ions (such as lithium ions) are embedded and extracted back and forth between the positive electrode and the negative electrode. Optionally, the electrode assembly includes a separator disposed between the positive electrode and the negative electrode, and the separator can play a role in preventing short circuit between the positive and negative electrodes and at the same time allow active ions to pass through.

[0067] Exemplarily, both the positive electrode and the negative electrode have tabs for transmitting current.

[0068] Generally, a cylindrical battery cell is provided with an electrode lead-out portion and a current collector member. The current collector member is used to connect the tab and the electrode lead-out portion. The electrode lead-out portion can be used to connect to an external circuit to achieve the charging and discharging of the cylindrical battery cell.

[0069] Generally, the current collector member is connected to the tab by welding. In the related art, multiple linear weld marks are formed between the current collector member and the tab, and the multiple weld marks are arranged radially; however, in a cylindrical battery cell, the tab generally has a circular structure, and the inner ends of the multiple weld marks are at a small distance. During the welding process, heat accumulation is likely to occur in the middle of the tab, leading to the risk of short circuit due to the heat deformation of the separator. Additionally, affected by the inner-end distance of the weld marks, the number of weld marks is also limited, which will affect the welding area of the part of the tab near the edge, resulting in abnormal temperature rise of the tab and the current collector member under high-current conditions and affecting the reliability of the battery cell.

[0070] In view of this, the embodiments of the present application provide a technical solution, which adopts two types of welding imprints with different lengths, and arranges the shorter welding imprints in the area closer to the outside of the tab, so as to increase the current-carrying area between the current collector member and the tab, reduce heat accumulation during the forming process of the welding imprint, lower the temperature rise, and improve the reliability and cycling performance of the battery cell.

[0071] The cylindrical battery cell described in the embodiments of the present application is applicable to batteries and electrical devices using the batteries.

[0072] The electrical devices disclosed in the embodiments of the present application can be devices using batteries as power sources or various energy storage systems using batteries as energy storage elements. The electrical devices can be, but are not limited to, mobile phones, tablets, laptop computers, electric toys, power tools, battery cars, electric vehicles, ships, spacecraft, etc. Among them, the electric toys can include fixed or mobile electric toys, such as game consoles, electric vehicle toys, electric ship toys, and electric aircraft toys, etc., and the spacecraft can include airplanes, rockets, space shuttles, and spaceships, etc.

[0073] For the convenience of description, the following embodiments take the electrical device as a vehicle as an example for illustration.

[0074] Figure 1 It is a schematic structural diagram of a vehicle provided by some embodiments of the present application.

[0075] As Figure 1 shown, a battery 2 is arranged inside the vehicle 1, and the battery 2 can be arranged at the bottom, head or tail of the vehicle 1. The battery 2 can be used for power supply of the vehicle 1. For example, the battery 2 can be used as the operating power source of the vehicle 1.

[0076] The vehicle 1 may further include a controller 3 and a motor 4. The controller 3 is used to control the battery 2 to supply power to the motor 4. For example, it is used for the working power requirements during the start, navigation and driving of the vehicle 1.

[0077] In some embodiments of the present application, the battery 2 can not only be used as the operating power source of the vehicle 1, but also be used as the driving power source of the vehicle 1, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1.

[0078] Figure 2 It is an exploded view of a battery provided by some embodiments of the present application. As Figure 2 shown, the battery 2 includes a box body 5 and cylindrical battery cells ( Figure 2 not shown), and the cylindrical battery cells are accommodated in the box body 5.

[0079] The box body 5 is used to accommodate cylindrical battery cells, and the box body 5 can have various structures. In some embodiments, the box body 5 may include a first box body part 5a and a second box body part 5b. The first box body part 5a and the second box body part 5b are covered with each other, and the first box body part 5a and the second box body part 5b jointly define an accommodation space 5c for accommodating the cylindrical battery cells. The second box body part 5b can be a hollow structure with one end open, and the first box body part 5a is a plate-like structure. The first box body part 5a covers the open side of the second box body part 5b to form the box body 5 with the accommodation space 5c; both the first box body part 5a and the second box body part 5b can also be hollow structures with one side open, and the open side of the first box body part 5a covers the open side of the second box body part 5b to form the box body 5 with the accommodation space 5c. Of course, the first box body part 5a and the second box body part 5b can have various shapes, such as a cylinder, a cuboid, etc.

[0080] To improve the sealing performance after the connection between the first box body part 5a and the second box body part 5b, a sealing member can also be provided between the first box body part 5a and the second box body part 5b, such as sealant, sealing ring, etc.

[0081] Assume that the first box body part 5a covers the top of the second box body part 5b. The first box body part 5a can also be called the upper box cover, and the second box body part 5b can also be called the lower box body.

[0082] In the battery 2, there can be one or more cylindrical battery cells. If there are multiple cylindrical battery cells, the multiple cylindrical battery cells can be connected in series, in parallel, or in a mixed connection. A mixed connection means that there are both series and parallel connections among the multiple cylindrical battery cells. The multiple cylindrical battery cells can be directly connected in series, in parallel, or in a mixed connection together, and then the whole formed by the multiple cylindrical battery cells is accommodated in the box body 5; of course, it can also be that multiple cylindrical battery cells are first connected in series, in parallel, or in a mixed connection to form a battery module 6, and then multiple battery modules 6 are connected in series, in parallel, or in a mixed connection to form a whole and are accommodated in the box body 5.

[0083] The cylindrical battery cell can be the smallest unit that makes up the battery.

[0084] In some embodiments, the box body 5 can be part of the chassis structure of a vehicle. For example, a part of the box body 5 can become at least part of the floor of the vehicle, or a part of the box body 5 can become at least part of the crossbeam and longitudinal beam of the vehicle.

[0085] In some embodiments, the battery 2 can be an energy storage device. The energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0086] Figure 3 For Figure 2 The structural schematic diagram of the battery module shown.

[0087] In some embodiments, such asFigure 3 As shown, there are multiple cylindrical battery cells 7. The multiple cylindrical battery cells 7 are first connected in series, parallel, or in a hybrid connection to form a battery module 6. Then, multiple battery modules 6 are connected in series, parallel, or in a hybrid connection to form a whole and are accommodated in a box.

[0088] The multiple cylindrical battery cells 7 in the battery module 6 can be electrically connected through a busbar component to achieve parallel, series, or hybrid connection of the multiple cylindrical battery cells 7 in the battery module 6. The busbar component can be one or more, and each busbar component is used to electrically connect at least two cylindrical battery cells 7.

[0089] The cylindrical battery cell can be a lithium-ion battery cell, a sodium-ion battery cell, a sodium-lithium-ion battery cell, a lithium-metal battery cell, a sodium-metal battery cell, a lithium-sulfur battery cell, a magnesium-ion battery cell, a nickel-metal hydride battery cell, a nickel-cadmium battery cell, a lead-acid battery cell, etc.

[0090] Figure 4 Schematic diagram of the structure of the cylindrical battery cell provided by some embodiments of the present application; Figure 5 is Figure 4 Explosion schematic diagram of the cylindrical battery cell shown; Figure 6 is Figure 4 Cross-sectional schematic diagram of the cylindrical battery cell shown; Figure 7 Schematic diagram of the electrode assembly of the cylindrical battery cell provided by some embodiments of the present application; Figure 8 Schematic diagram after welding of the electrode assembly and the current collector member of the cylindrical battery cell provided by some embodiments of the present application; Figure 9 is Figure 6 Enlarged schematic diagram at the round frame.

[0091] Referring to Figures 4 to 9 , some embodiments of the present application provide a cylindrical battery cell 7, which includes a housing 20 and an electrode assembly 10, and at least a part of the electrode assembly 10 is accommodated in the housing 20.

[0092] The housing 20 is a hollow structure, and an accommodation space for accommodating the electrode assembly 10 and the electrolyte is formed inside it. The housing 20 of the cylindrical battery cell 7 is a cylindrical housing.

[0093] As an example, the housing 20 includes a shell 21 and an end cap 22. The shell 21 has an opening, and the end cap 22 is used to cover the opening.

[0094] The shell 21 is a component for cooperating with the end cap 22 to form the internal cavity of the cylindrical battery cell 7. The formed internal cavity can be used to accommodate the electrode assembly 10, the electrolyte, and other components.

[0095] The housing 21 and the end cap 22 can be independent components. Exemplarily, an opening can be provided on the housing 21, and the end cap 22 can be covered at the opening to form the internal cavity of the cylindrical battery cell 7.

[0096] The material of the housing 21 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, etc.

[0097] The shape of the end cap 22 can be adapted to the shape of the housing 21 to cooperate with the housing 21. The material of the end cap 22 can be the same as or different from that of the housing 21. Optionally, the end cap 22 can be made of a material with a certain hardness and strength (such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.). In this way, the end cap 22 is not easily deformed when being squeezed or collided, enabling the cylindrical battery cell 7 to have higher structural strength and improved reliability.

[0098] The end cap 22 is connected to the housing 21 by welding, bonding, clamping or other means.

[0099] The housing 21 can be open at one end or both ends. In some examples, the housing 21 can be a structure with an opening on one side, and the end cap 22 is provided as one and covers the housing 21. In other examples, the housing 21 can also be a structure with openings on both sides, and the end caps 22 are provided as two, and the two end caps 22 respectively cover the two openings of the housing 21.

[0100] The electrode assembly 10 is a component that undergoes an electrochemical reaction in the cylindrical battery cell 7. The housing 21 can contain one or more electrode assemblies 10.

[0101] The electrode assembly 10 includes a positive electrode and a negative electrode. During the charging and discharging process of the battery cell, active ions (such as lithium ions) are embedded and extracted back and forth between the positive electrode and the negative electrode.

[0102] In some embodiments, the positive electrode can be a positive electrode sheet, and the positive electrode sheet can include a positive electrode current collector and a positive electrode film layer provided on at least one surface of the positive electrode current collector.

[0103] As an example, the positive electrode current collector has two surfaces opposite to each other in its own thickness direction, and the positive electrode film layer is provided on either or both of the two opposite surfaces of the positive electrode current collector.

[0104] As an example, the positive electrode current collector can be a metal foil or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrodes, carbon, nickel, or titanium, etc. can be used. The composite current collector can include a polymer material substrate and a metal layer. The composite current collector can be formed by forming a metal material (such as aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver, and silver alloy, etc.) on a polymer material substrate (such as substrates of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0105] As an example, the positive electrode film layer includes a positive electrode active material, and the positive electrode active material can include at least one of the following materials: lithium-containing phosphates, lithium transition metal oxides, and their respective modified compounds. However, the present application is not limited to these materials, and other conventional materials that can be used as battery positive electrode active materials can also be used. These positive electrode active materials can be used alone or in combination of two or more. Among them, examples of lithium-containing phosphates can include, but are not limited to, lithium iron phosphate (such as LiFePO4 (which can also be abbreviated as LFP)), composites of lithium iron phosphate and carbon, lithium manganese phosphate (such as LiMnPO4), composites of lithium manganese phosphate and carbon, lithium manganese iron phosphate, composites of lithium manganese iron phosphate and carbon, etc. Examples of lithium transition metal oxides can include, but are not limited to, lithium cobalt oxide (such as LiCoO2), lithium nickel oxide (such as LiNiO2), lithium manganese oxide (such as LiMnO2, LiMn2O4), lithium nickel cobalt oxide, lithium manganese cobalt oxide, lithium nickel manganese oxide, lithium nickel cobalt manganese oxide (such as LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2 (which can also be abbreviated as NCM 333 )、LiNi 0.5 Co 0.2 Mn 0.3 O2 (which can also be abbreviated as NCM 523 )、LiNi 0.5 Co 0.25 Mn 0.25 O2 (which can also be abbreviated as NCM 211 )、LiNi 0.6 Co 0.2 Mn 0.2 O2 (which can also be abbreviated as NCM 622 )、LiNi 0.8 Co 0.1 Mn 0.1 O2 (which can also be abbreviated as NCM 811 )、lithium nickel cobalt aluminum oxide (such as LiNi 0.80 Co 0.15 Al 0.05 O2) and their modified compounds, etc.

[0106] In some embodiments, the positive electrode can be made of foam metal or foam carbon. The foam metal can be foam nickel, foam copper, foam aluminum, foam alloy, etc. When the foam metal is used as the positive electrode, a positive electrode film layer may not be provided on the surface of the foam metal, or of course, a positive electrode film layer can also be provided. As an example, a lithium source material, potassium metal or sodium metal can also be filled and / or deposited in the foam metal, and the lithium source material is lithium metal and / or lithium-rich material.

[0107] In some embodiments, the negative electrode can be a negative electrode sheet, and the negative electrode sheet can include a negative electrode current collector.

[0108] As an example, the negative electrode current collector can be made of a metal foil, foam metal, foam carbon or a composite current collector. For example, as the metal foil, aluminum or stainless steel with a silver surface treatment, stainless steel, copper, aluminum, nickel, carbon electrode, carbon, nickel or titanium, etc. can be used. The foam metal can be foam nickel, foam copper, foam aluminum, foam alloy, etc. The composite current collector can include a polymer material substrate layer and a metal layer. The composite current collector can be formed by forming a metal material (such as copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene, polyethylene terephthalate, polybutylene terephthalate, polystyrene, polyethylene, etc.).

[0109] As an example, the negative electrode sheet can include a negative electrode current collector and a negative electrode film layer provided on at least one surface of the negative electrode current collector.

[0110] As an example, the negative electrode current collector has two surfaces opposite to each other in its own thickness direction, and the negative electrode film layer is provided on any one or both of the two opposite surfaces of the negative electrode current collector.

[0111] As an example, the negative electrode film layer includes a negative electrode active material. As an example, the negative electrode active material can include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based material, tin-based material, and lithium titanate, etc. The silicon-based material can be selected from at least one of elemental silicon, silicon oxide compound, silicon-carbon composite, silicon-nitrogen composite, and silicon alloy. The tin-based material can be selected from at least one of elemental tin, tin oxide compound, and tin alloy. However, the present application is not limited to these materials, and other conventional materials that can be used as the negative electrode active material of the battery can also be used. These negative electrode active materials can be used alone or in combination of two or more.

[0112] In some embodiments, the material of the positive electrode current collector can be aluminum, and the material of the negative electrode current collector can be copper.

[0113] In some embodiments, the electrode assembly 10 further includes a separator disposed between the positive electrode and the negative electrode. The separator can prevent short - circuit between the positive and negative electrodes and allow active ions to pass through.

[0114] In some embodiments, the separator is a separator membrane. Any well - known porous structure separator membrane with good chemical stability and mechanical stability can be selected in the embodiments of the present application.

[0115] As an example, the main material of the separator membrane can be selected from at least one of glass fiber, non - woven fabric, polyethylene, polypropylene, polyvinylidene fluoride, and ceramics. The separator membrane can be a single - layer film or a multi - layer composite film. When the separator membrane is a multi - layer composite film, the materials of each layer can be the same or different. The separator can be a single component located between the positive and negative electrodes or attached to the surfaces of the positive and negative electrodes.

[0116] In some embodiments, the separator is a solid electrolyte. The solid electrolyte is disposed between the positive electrode and the negative electrode and serves to transport ions and isolate the positive and negative electrodes at the same time.

[0117] In some embodiments, the cylindrical battery cell 7 further includes an electrolyte, which plays a role in conducting ions between the positive and negative electrodes. The type of electrolyte in the present application can be selected according to requirements. The electrolyte can be liquid, gel - state or solid - state.

[0118] Among them, the liquid electrolyte includes electrolyte salts and solvents.

[0119] In some embodiments, the electrolyte salt can be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis - (fluorosulfonyl) imide, lithium bis - (trifluoromethanesulfonyl) imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium bis - (oxalato) borate, lithium difluoro - bis - (oxalato) phosphate, and lithium tetrafluoro - bis - (oxalato) phosphate.

[0120] In some embodiments, the solvent can be selected from at least one of ethylene carbonate, propylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butylene carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4 - butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone. The solvent can also be an ether solvent. The ether solvent can include one or more of ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,3 - dioxolane, tetrahydrofuran, methyltetrahydrofuran, diphenyl ether, and crown ether.

[0121] Among them, the gel - state electrolyte includes a polymer as the skeleton network of the electrolyte, combined with an ionic liquid - lithium salt.

[0122] Among them, the solid electrolyte includes polymer solid electrolyte, inorganic solid electrolyte, and composite solid electrolyte.

[0123] As an example, the polymer solid electrolyte can be polyether (polyethylene oxide), polysiloxane, polycarbonate, polyacrylonitrile, polyvinylidene fluoride, polymethyl methacrylate, single-ion polymer, polyionic liquid-lithium salt, cellulose, etc.

[0124] As an example, the inorganic solid electrolyte can be one or more of oxide solid electrolytes (crystalline perovskite, sodium superionic conductor, garnet, amorphous LiPON film), sulfide solid electrolytes (crystalline lithium superionic conductor (lithium germanium phosphorus sulfur, argyrodite), amorphous sulfide), and halide solid electrolytes, nitride solid electrolytes, and hydride solid electrolytes.

[0125] As an example, the composite solid electrolyte is formed by adding an inorganic solid electrolyte filler to the polymer solid electrolyte.

[0126] In some embodiments, the electrode assembly 10 has a wound structure. Exemplarily, the positive electrode sheet and the negative electrode sheet are wound into a cylindrical wound structure.

[0127] In some embodiments, the electrode assembly 10 includes an electrode body 11, a first tab 12, and a second tab 13, and the first tab 12 and the second tab 13 have opposite polarities. One of the first tab 12 and the second tab 13 is a positive tab, and the other is a negative tab.

[0128] As an example, the electrode assembly 10 includes a positive electrode sheet and a negative electrode sheet. The portions of the positive electrode sheet and the negative electrode sheet having the active material constitute the electrode body 11 of the electrode assembly 10, the portion of the positive electrode sheet without the active material constitutes the positive tab, and the portion of the negative electrode sheet without the active material constitutes the negative tab. The positive tab and the negative tab can be located at one end of the electrode body 11 together or at both ends of the electrode body 11 respectively. During the charge and discharge process of the battery, the positive active material and the negative active material react with the electrolyte.

[0129] In some embodiments, the cylindrical battery cell 7 further includes a first electrode lead-out portion 7a and a second electrode lead-out portion 7b, the first electrode lead-out portion 7a is electrically connected to the first tab 12, and the second electrode lead-out portion 7b is electrically connected to the second tab 13.

[0130] The first electrode lead-out portion 7a and the second electrode lead-out portion 7b are insulated from each other.

[0131] The first electrode lead-out portion 7a and the second electrode lead-out portion 7b are used to connect to an external circuit to enable charging or discharging of the cylindrical battery cell 7. Exemplarily, when multiple cylindrical battery cells 7 are assembled into a group, the first electrode lead-out portion 7a and the second electrode lead-out portion 7b are used to connect to a bus bar component.

[0132] The first electrode lead-out portion 7a can be an electrode terminal 30 provided on the outer casing 20. The electrode terminal 30 is independently formed with the outer casing 20 and assembled together during the production process of the cylindrical battery cell 7. As an example, the electrode terminal 30 is insulatingly provided on the end cap 22 or the housing 21.

[0133] Alternatively, the first electrode lead-out portion 7a can also be a part of the outer casing 20. For example, the first electrode lead-out portion 7a can be the end cap 22 of the outer casing 20, or the first electrode lead-out portion 7a is the end wall 211 of the housing 21 that abuts against the end cap 22.

[0134] The second electrode lead-out portion 7b can be an electrode terminal 30 provided on the outer casing 20. Alternatively, the second electrode lead-out portion 7b can be a part of the outer casing 20. For example, the second electrode lead-out portion 7b can be the end cap 22 of the outer casing 20, or the second electrode lead-out portion 7b is the end wall 211 of the housing 21 that abuts against the end cap 22.

[0135] In some embodiments, the first electrode lead-out portion 7a is the electrode terminal 30, the second electrode lead-out portion 7b is the end wall 211 of the housing 21, and the electrode terminal 30 is insulatingly provided on the end wall 211. In some other examples, the second electrode lead-out portion 7b is the electrode terminal 30, the first electrode lead-out portion 7a is the end wall 211 of the housing 21, and the electrode terminal 30 is insulatingly provided on the end wall 211.

[0136] In some embodiments, the cylindrical battery cell 7 further includes a current collecting member 40 that electrically connects the first tab 12 to the first electrode lead-out portion 7a.

[0137] The current collecting member 40 can be directly connected to the first electrode lead-out portion 7a. For example, the current collecting member 40 can be welded to the first electrode lead-out portion 7a to achieve electrical connection between the current collecting member 40 and the first electrode lead-out portion 7a.

[0138] Alternatively, the current collecting member 40 can also be indirectly connected to the first electrode lead-out portion 7a through other parts. For example, when the first electrode lead-out portion 7a is the end wall 211 of the housing 21, the current collecting member 40 can be connected to the side wall 212 of the housing 21 to be electrically connected to the end wall 211 through the side wall 212.

[0139] In some embodiments, the second electrode lead portion 7b can be directly connected to the second tab 13 to achieve the electrical connection between the second tab 13 and the electrode lead portion; alternatively, the second electrode lead portion 7b is electrically connected to the second tab 13 through another current collector member 40.

[0140] In some embodiments, the first electrode lead portion 7a is an electrode terminal 30.

[0141] In some embodiments, the electrode terminal 30 includes a terminal body 31. A terminal recess 311 is provided on a side of the terminal body 31 away from the current collector member 40, and the bottom wall of the terminal recess 311 is welded to the current collector member 40.

[0142] Exemplarily, when welding the terminal body 31 and the current collector member 40, the laser can irradiate the bottom wall of the terminal recess 311 from the outside to achieve external welding.

[0143] In some embodiments, the electrode terminal 30 further includes a cover plate 32. The cover plate 32 is fixed to the terminal body 31 and is used to cover the terminal recess 311 from the outside.

[0144] In some embodiments, the cylindrical battery cell 7 includes a housing 20, a first electrode lead portion 7a, an electrode assembly 10, and a current collector member 40.

[0145] The first electrode lead portion 7a is disposed on the housing 20. The electrode assembly 10 is accommodated in the housing 20. The electrode assembly 10 is of a wound structure and includes an electrode body 11 and a first tab 12 led out from an end of the electrode body 11.

[0146] The current collector member 40 is electrically connected to the first electrode lead portion 7a. The current collector member 40 is located on a side of the first tab 12 away from the electrode body 11. The current collector member 40 is welded to the first tab 12 and forms a plurality of weld mark groups 50. The plurality of weld mark groups 50 are arranged at intervals along the circumferential direction V of the current collector member 40.

[0147] Each weld mark group 50 includes at least one first weld mark 51 and at least one second weld mark 52. In the direction pointing from the outside of the electrode assembly 10 to the central axis C of the electrode assembly 10, the first weld mark 51 and the second weld mark 52 extend linearly. The first weld mark 51 has a first end 511 close to the central axis C and a second end 512 away from the central axis C. The second weld mark 52 has a third end 521 close to the central axis C and a fourth end 522 away from the central axis C. The extension length L1 of the first weld mark 51 is greater than the extension length L2 of the second weld mark 52, and the distance between the third end 521 and the second end 512 is less than the distance between the third end 521 and the first end 511.

[0148] The central axis C of the electrode assembly 10 is a virtual line. As an example, both the positive electrode plate and the negative electrode plate can be wound around the central axis C.

[0149] As an example, the axial direction Z of the cylindrical battery cell 7 can be parallel to the central axis C of the electrode assembly 10. The first tab 12 is led out from one end of the electrode body 11 along the axial direction Z.

[0150] As an example, the circumferential direction V of the current collector member 40 is perpendicular to the central axis C of the electrode assembly 10.

[0151] Along the circumferential direction V of the current collector member 40, a plurality of weld mark groups 50 can be arranged at equal angular intervals or at unequal angular intervals. Optionally, the plurality of weld mark groups 50 are arranged at equal angular intervals; further optionally, the plurality of weld mark groups 50 are rotationally symmetric about the central axis C.

[0152] Each weld mark group 50 can include one or more first weld marks 51, and each weld mark group 50 can include one or more first weld marks 51. As an example, the number of first weld marks 51 in the plurality of weld mark groups 50 is the same, and the number of second weld marks 52 in the plurality of weld mark groups 50 is the same.

[0153] The first weld mark 51 and the second weld mark 52 extend linearly. Exemplarily, the first weld mark 51 can extend in a straight line or in a curve; the second weld mark 52 can extend in a straight line or in a curve.

[0154] As an example, the direction pointing from the outside of the electrode assembly 10 to the central axis C of the electrode assembly 10 is perpendicular to the central axis C.

[0155] When the first weld mark 51 extends from the first end 511 to the second end 512, the first weld mark 51 generally has a tendency to gradually move away from the central axis C; in other words, when the first weld mark 51 extends from the second end 512 to the first end 511, the first weld mark 51 generally has a tendency to gradually approach the central axis C.

[0156] Exemplarily, when welding the current collector member 40 and the first tab 12, it can be welded from the first end 511 to the second end 512, or it can be welded from the second end 512 to the first end 511.

[0157] When the second weld mark 52 extends from the third end 521 to the fourth end 522, the second weld mark 52 generally has a tendency to gradually move away from the central axis C; in other words, when the second weld mark 52 extends from the fourth end 522 to the third end 521, the second weld mark 52 generally has a tendency to gradually approach the central axis C.

[0158] Exemplarily, when welding the current collector member 40 and the first tab 12, it can be welded from the third end 521 to the fourth end 522, or it can be welded from the fourth end 522 to the third end 521.

[0159] In the embodiment of the present application, the first welding mark 51 has a relatively large extension length, and it can simultaneously transmit the current of the part of the first tab 12 close to the central axis C and the current of the part of the first tab 12 far from the central axis C. The perimeter of the part of the first tab 12 far from the central axis C is relatively large, and the requirement for the current-carrying area is also relatively high. The second welding mark 52 is arranged outside relative to the first end 511, and it can jointly transmit the current of the part of the first tab 12 far from the central axis C with the first welding mark 51, thereby improving the current-carrying capacity, reducing the temperature rise, improving the fast charging capacity of the battery cell, and enhancing the cycle performance and reliability of the battery cell.

[0160] The farther away from the central axis C, the larger the dimensions of the first tab 12 and the current collector member 40 in the circumferential direction V. By arranging the second welding mark 52 with a relatively small extension length outside, the distance between the first welding mark 51 and the second welding mark 52 can be increased, thereby reducing heat accumulation during the welding process, reducing the temperature rise, and improving the reliability. The perimeter of the part of the first tab 12 close to the central axis C is relatively small, and its distance from the first end 511 is relatively close. Therefore, the part of the first tab 12 close to the central axis C has a relatively small requirement for the current-carrying area, and the second welding mark 52 can be shortened to reduce the heat generated during welding, simplify the welding process, and improve the reliability.

[0161] In the embodiment of the present application, by adopting two first welding marks 51 and second welding marks 52 with different extension lengths and arranging the second welding mark 52 in the outer region of the first tab 12, the current-carrying area between the current collector member 40 and the tab is increased, heat accumulation is reduced during the formation of the welding mark, the temperature rise is reduced, and the reliability and cycle performance of the battery cell are improved.

[0162] The second welding mark 52 is arranged outside, which can increase the distance between the first welding mark 51 and the second welding mark 52, thereby reducing the risk of explosion points caused by welding twice at the same position of the current collector member 40.

[0163] In some embodiments, during the cycle of the battery cell, the electrode assembly 10 will expand; when the electrode assembly 10 expands, the outer region of the first tab 12 will be subjected to a relatively large tensile force; in the embodiment of the present application, the first welding mark 51 and the second welding mark 52 are simultaneously arranged in the outer region of the first tab 12, which can reduce the force on a single welding mark, reduce the risk of welding mark tearing, and improve the reliability.

[0164] In some embodiments, the current collector member 40 and the first tab 12 are laser welded. Exemplarily, during welding, the laser irradiates the surface of the current collector member 40 facing away from the first tab 12.

[0165] In some embodiments, the first tab 12 is wound to form N winding turns. Exemplarily, the first tab 12 is wound around the central axis C.

[0166] As an example, along the winding direction X of the first tab 12, each turn of the first tab 12 starting from the winding start end 121 is a winding turn. The starting end of the first winding turn is the winding start end of the first tab 12, and the ending end of the first winding turn is the starting end of the second winding turn.

[0167] Except for the last winding turn, other winding turns are full turns. The last winding turn is not required to be a full turn. For example, the last winding turn can be 1 / 4 turn, 1 / 2 turn, or 3 / 4 turn.

[0168] The first tab 12 with a winding structure can increase the current-carrying area of the first tab 12 and improve the fast charging ability of the battery cell.

[0169] Some winding turns close to the central axis C have a smaller circumference, and these winding turns also have a smaller requirement for the current-carrying area. Therefore, the current of the winding turns close to the central axis C can be conducted by the first welding mark 51; some winding turns close to the central axis C have a smaller circumference, and these winding turns also have a larger requirement for the current-carrying area. Therefore, the current of the winding turns far from the central axis C can be conducted by using both the first welding mark 51 and the second welding mark 52.

[0170] In some embodiments, the ends of multiple winding turns far from the electrode body 11 are bent to form an overlapping area, and in the overlapping area, the first tab 12 has a multi-layer structure in the axial direction Z.

[0171] The multi-layer structure is welded to the current collector member 40 to form a plurality of welding mark groups 50. Welding the overlapping area to the current collector member 40 can not only reduce the risk of false soldering but also increase the welding area between the first tab 12 and the current collector member 40, improving the current-carrying capacity.

[0172] In some embodiments, the first tab 12 is bent by a flattening process or a smoothing process to form an overlapping area. Exemplarily, Figure 7 The first tab 12 shown before flattening or the first tab 12 before smoothing.

[0173] In some embodiments, the first tab 12 is a cylindrical structure.

[0174] In some embodiments, the first tab 12 is wound to form N winding turns, and the second welding mark 52 is connected to M winding turns, where 0.05 ≤ M / N ≤ 0.4.

[0175] As an example, M / N is 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, or 0.4.

[0176] Exemplarily, M is an integer.

[0177] Limiting M / N to be greater than or equal to 0.05 can enable the second weld mark 52 to connect to more wound turns, increase the current-carrying area between the wound turns far from the central axis C and the current collector member 40, improve the current-carrying capacity, reduce the temperature rise, and improve the cycling performance of the cylindrical battery cell 7. Limiting M / N to be less than or equal to 0.4 can increase the distance between the third end 521 and the central axis C and the distance between the third end 521 and the first end 511, reduce the heat accumulation during welding, and improve the reliability.

[0178] In some embodiments, 0.1 ≤ M / N ≤ 0.2.

[0179] In some embodiments, the first weld mark 51 is connected to K wound turns. M < K < N. Exemplarily, K is an integer.

[0180] In some embodiments, 0.1 ≤ M / K ≤ 0.5. Optionally, 0.2 ≤ K / M ≤ 0.4.

[0181] In some embodiments, both the first weld mark 51 and the second weld mark 52 extend along a straight line.

[0182] The first weld mark 51 is a straight weld mark, and the second weld mark 52 is a straight weld mark.

[0183] It should be noted here that a straight line not only includes the case of an absolute straight line but also includes the case that is generally considered a straight line in engineering common knowledge. For example, due to process errors, local fluctuations may occur during the forming of the weld mark.

[0184] The first weld mark 51 can extend along the radial direction, that is, the extension line of the first weld mark 51 passes through the central axis C. Of course, the extension direction of the first weld mark 51 can also intersect with the radial direction, that is, the extension line of the first weld mark 51 does not pass through the central axis C.

[0185] The second weld mark 52 can extend along the radial direction, that is, the extension line of the second weld mark 52 passes through the central axis C. Of course, the extension direction of the second weld mark 52 can also intersect with the radial direction, that is, the extension line of the second weld mark 52 does not pass through the central axis C.

[0186] Adopting the straight first weld mark 51 and the second weld mark 52 can simplify the welding process and reduce the assembly difficulty of the battery cell.

[0187] In some embodiments, the first weld mark 51 extends along the radial direction of the current collector member 40. Exemplarily, the extension line of the first weld mark 51 passes through the central axis C.

[0188] On the premise that the extension length is certain, setting the first weld mark 51 to extend radially along the current collector member 40 can improve the current-carrying capacity between the current collector member 40 and the first tab 12. Exemplarily, the first tab 12 is wound to form a plurality of winding turns. Setting the first weld mark 51 to extend radially along the current collector member 40 can enable the first weld mark 51 to connect more winding turns.

[0189] In some embodiments, the second weld mark 52 extends radially along the current collector member 40.

[0190] On the premise that the extension length is certain, setting the second weld mark 52 to extend radially along the current collector member 40 can improve the current-carrying capacity between the current collector member 40 and the second tab 13. Exemplarily, the second tab 13 is wound to form a plurality of winding turns. Setting the second weld mark 52 to extend radially along the current collector member 40 can enable the second weld mark 52 to connect more winding turns.

[0191] In some embodiments, the weld mark group 50 has 3 - 8. Optionally, the weld mark group 50 has 4 - 6.

[0192] In some embodiments, the weld mark group 50 includes two first weld marks 51. Of course, the weld mark group 50 may also include more than three first weld marks 51.

[0193] The shapes of the two weld marks of the weld mark group 50 may be the same or different.

[0194] In the weld mark group 50, the second weld mark 52 may be located between the two first weld marks 51 or on the same side of the two first weld marks 51.

[0195] By providing two first weld marks 51, the current-carrying capacity between the current collector member 40 and the first tab 12 can be further improved. By increasing the number of the first weld marks 51 of the weld mark group 50, the requirement for the number of the weld mark groups 50 can be reduced.

[0196] In some embodiments, on the circumferential direction V of the current collector member 40, the third end 521 is located between two adjacent first weld marks 51.

[0197] Exemplarily, when observing along the direction perpendicular to the central axis C, the circle centered on the central axis C and passing through the third end 521 intersects the two first weld marks 51 of a weld mark group 50.

[0198] Utilizing the space between the two first weld marks 51 to provide the second weld mark 52 can improve the space utilization rate. Compared with the solution of providing the second weld mark 52 outside the two first weld marks 51, the embodiment of the present application can increase the distance between the two first weld marks 51, reduce heat accumulation, and reduce the risk of repeated welding.

[0199] In some embodiments, the weld mark group 50 includes a second weld mark 52.

[0200] In some embodiments, on the circumferential direction V of the current collector member 40, the fourth end 522 is located between two adjacent first weld marks 51.

[0201] In the radial direction of the current collector member 40, the fourth end 522 does not extend outward beyond the circle centered on the central axis C and passing through the second end 512.

[0202] During the process of welding the current collector member 40 and the first tab 12, the fourth end 522 of the second weld mark 52 can use the second end 512 of the first weld mark 51 as a reference, thereby reducing the risk of welding outside the current collector member 40 and improving reliability.

[0203] In some embodiments, on the circumferential direction V of the current collector member 40, the second weld mark 52 is entirely located between the first weld marks 51.

[0204] In some embodiments, the minimum distance between the fourth end 522 and the central axis C is less than or equal to the minimum distance between the second end 512 and the central axis C.

[0205] During the process of welding the current collector member 40 and the first tab 12, the fourth end 522 of the second weld mark 52 can use the second end 512 of the first weld mark 51 as a reference, thereby reducing the risk of welding outside the current collector member 40 and improving reliability.

[0206] In some embodiments, on the circumferential direction V of the current collector member 40, the maximum distance D2 between two adjacent weld mark groups 50 is greater than the maximum size D3 of the weld mark group 50.

[0207] In the embodiments of the present application, the adjacent weld mark groups 50 are spaced at a relatively large distance. In other words, in addition to the area that needs to be welded on the current collector member 40, there is also a relatively large area available for external devices to press. When welding the current collector member 40 and the first tab 12, the external device can tightly press the current collector member 40 against the first tab 12 to make the current collector member 40 fit with the first tab 12 during the welding process, reducing the risk of false soldering.

[0208] In some embodiments, on the circumferential direction V of the current collector member 40, the distance between two adjacent weld mark groups 50 is greater than the distance between the two first weld marks 51 of the weld mark group 50.

[0209] It is supplemented here that when comparing the distance between two adjacent weld mark groups 50 with the distance between the two first weld marks 51 of the weld mark group 50, the comparison is made based on the same circle as the reference.

[0210] Exemplarily, a circle with the central axis C as the center and a radius of R passes through the first weld mark 51 of the weld mark group 50; then, the arc length of the part of this circle located between two adjacent weld mark groups 50 can be the pitch between two adjacent weld mark groups 50 in the circumferential direction V of the current collecting member 40, and the arc length of the part of this circle located between the outer edges of the two first weld marks 51 of the weld mark group 50 is the pitch between the two first weld marks 51 of the weld mark group 50. When comparing with any circle with the central axis C as the center and passing through the first weld mark 51 as a reference, it is satisfied that: in the circumferential direction V of the current collecting member 40, the pitch between two adjacent weld mark groups 50 is greater than the pitch between the two first weld marks 51 of the weld mark group 50.

[0211] When welding the current collecting member 40 and the first pole ear 12, an external device can abut against the part between two adjacent weld mark groups 50 and press the current collecting member 40 against the first pole ear 12, so as to make the current collecting member 40 fit with the first pole ear 12 during the welding process and reduce the risk of false welding.

[0212] In some embodiments, the first weld mark 51 extends along the radial direction of the current collecting member 40. The current collecting member 40 includes a first sector area 41 and a second sector area 42. In the circumferential direction V of the current collecting member 40, the first sector area 41 is located between the two first weld marks 51 of the weld mark group 50, and the second sector area 42 is located between two adjacent weld mark groups 50. The central angle α of the second sector area 42 is greater than the central angle β of the first sector area 41.

[0213] As an example, in Figure 8 , the dashed line F1, the dashed line F2, and the two first weld marks 51 of the weld mark group 50 define the first sector area 41. Exemplarily, the dashed line F1 is an arc on a circle with the central axis C as the center and passing through the first end 511, and the dashed line F2 is an arc on a circle with the central axis C as the center and passing through the second end 512.

[0214] As an example, in Figure 8 , the dashed line F3, the dashed line F4, and two adjacent weld mark groups 50 define the second sector area 42. Exemplarily, the dashed line F3 is an arc on a circle with the central axis C as the center and passing through the first end 511, and the dashed line F4 is an arc on a circle with the central axis C as the center and passing through the second end 512.

[0215] When welding the current collecting member 40 and the first pole ear 12, an external device can abut against the second sector area 42 and press the current collecting member 40 against the first pole ear 12, so as to make the current collecting member 40 fit with the first pole ear 12 during the welding process and reduce the risk of false welding. The second sector area 42 has a larger area, so that the pressure-receiving area of the current collecting member 40 can be increased and the welding stability can be improved.

[0216] In some embodiments, D2 is the arc length of the dashed line F4.

[0217] In some embodiments, D3 is: the arc length of the dashed line F2 + 2×W1. W1 is the width of the first welding mark.

[0218] In some embodiments, a part of the first sector area 41 is welded to the first tab 12 to form a second welding mark 52. Since the first sector area 41 has a smaller central angle, therefore, by providing a shorter second welding mark 52 in the first sector area 41, the current-carrying capacity can be increased while maintaining the spacing between the first welding mark 51 and the second welding mark 52.

[0219] In some embodiments, there are multiple first sector areas 41 and multiple second sector areas 42. The multiple first sector areas 41 and the multiple second sector areas 42 are alternately arranged along the axial direction Z of the current collector member 40.

[0220] In some embodiments, the ratio of the extension length L2 of the second welding mark 52 to the extension length L1 of the first welding mark 51 is 0.1 - 0.5.

[0221] As an example, L2 / L1 is 0.1, 0.2, 0.3, 0.4, or 0.5.

[0222] Limiting L2 / L1 to be greater than or equal to 0.1 can improve the current-carrying capacity of the second welding mark 52 and reduce the temperature rise of the battery cell during cycling. Limiting L2 / L1 to be less than or equal to 0.5 can ensure that the minimum spacing between the second welding mark 52 and the first welding mark 51 meets the requirements.

[0223] In some embodiments, the width W2 of the second welding mark 52 is 0.5 times to 2 times the width W1 of the first welding mark 51.

[0224] As an example, W2 / W1 is 0.5, 0.8, 1, 1.5, 1.8, or 2.

[0225] Limiting W2 / W1 to be greater than or equal to 0.5 can provide a relatively large current-carrying area for the second welding mark 52 and reduce the temperature rise of the battery cell during cycling. Limiting W2 / W1 to be less than or equal to 2 can save the space occupied by the second welding mark 52 in the circumferential direction V of the current collector member 40, increase the minimum spacing between the second welding mark 52 and the first welding mark 51, reduce heat accumulation during the welding process, and improve reliability.

[0226] In some embodiments, W1 is 0.5 mm - 3 mm. Optionally, W1 is 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, or 3 mm.

[0227] In some embodiments, W2 is 0.5 mm - 3 mm. Optionally, W2 is 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, or 3 mm.

[0228] In some embodiments, the extension length L2 of the second welding mark 52 is greater than or equal to 2 mm.

[0229] In some embodiments, the minimum distance D1 between the third end 521 and the first welding mark 51 is greater than or equal to 0.5 times the width W1 of the first welding mark 51.

[0230] During welding, the width W1 of the first welding mark 51 is related to both the welding power and the heat generated by welding. In the embodiments of the present application, D1 / W1 is defined to be greater than or equal to 0.5 to reduce heat accumulation during welding, lower the risk of the first welding mark 51 and the second welding mark 52 joining and causing a blowout point, and improve reliability.

[0231] In some embodiments, at least a part of the first electrode lead-out portion 7a is located on the side of the current collector member 40 away from the first tab 12 and abuts against the current collector member 40. A plurality of welding mark groups 50 are arranged along the outer periphery of the first electrode lead-out portion 7a, and each welding mark group 50 is spaced apart from the first electrode lead-out portion 7a.

[0232] Due to welding process reasons, the flatness of the welding mark group 50 is poor; in the embodiments of the present application, the welding mark group 50 is arranged to avoid the first electrode lead-out portion 7a, so that the current collector member 40 can be attached to the first electrode lead-out portion 7a, improving the connection stability between the current collector member 40 and the first electrode lead-out portion 7a.

[0233] In some embodiments, the housing 20 includes a wall portion, and the first electrode lead-out portion 7a is an electrode terminal 30 insulatedly disposed on the wall portion.

[0234] As an example, the wall portion may be the end wall 211 of the housing 21, or may be the end cover 22. Optionally, the wall portion is the end wall 211.

[0235] In another embodiment, the housing 20 includes a housing 21 and an end cover 22. The housing 21 has an opening, and the end cover 22 covers the opening. The first electrode lead-out portion 7a is at least a part of one of the housing 21 and the end cover 22.

[0236] Optionally, the first electrode lead-out portion 7a is the end wall 211 of the housing 21. Alternatively, the first electrode lead-out portion 7a is the end cover 22.

[0237] In some embodiments, the second tab 13 is welded to another current collector member. Exemplarily, the welding method of the second tab 13 to the current collector member is the same as that of the first tab 12 to the current collector member 40, that is, the second tab 13 is welded to the current collector member and a welding mark group combining long and short welding marks is formed.

[0238] In some embodiments, the height of the housing 20 is 1.3 to 4 times the diameter of the housing 20. Exemplarily, the height of the housing 20 may be the dimension of the housing 20 along the axial direction Z.

[0239] Optionally, the height of the housing 20 is 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times, 2.0 times, 2.1 times, 2.2 times, 2.3 times, 2.4 times, 2.5 times, 2.6 times, 2.7 times, 2.8 times, 2.9 times, 3.0 times, 3.1 times, 3.2 times, 3.3 times, 3.4 times, 3.5 times, 3.6 times, 3.7 times, 3.8 times, 3.9 times or 4.0 times the diameter of the housing 20.

[0240] When the housing 20 meets the above size requirements, the structural stability of the housing 20 can be relatively high, and the reliability of the cylindrical battery cell can be improved.

[0241] In some embodiments, the height of the housing 20 is 1.5 to 2.5 times the diameter of the housing 20.

[0242] In some embodiments, the height of the housing 20 is 50 mm to 150 mm. For example, the height of the housing 20 is 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm, 80 mm, 85 mm, 90 mm, 95 mm, 100 mm, 105 mm, 110 mm, 115 mm, 120 mm, 125 mm, 130 mm, 135 mm, 140 mm, 145 mm or 150 mm.

[0243] Optionally, the height of the housing 20 is 60 mm - 100 mm.

[0244] In some embodiments, the diameter of the housing 20 is 40 mm to 80 mm. For example, the diameter of the housing 20 is 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 75 mm or 80 mm.

[0245] Optionally, the diameter of the housing 20 is 40 mm to 60 mm.

[0246] Figure 10 Schematic diagrams of the electrode assembly and the current collector member provided in other embodiments of the present application.

[0247] Referring to Figure 10 , in some embodiments, the welding mark group 50 further includes a third welding mark 53, and the third welding mark 53 connects the first ends 511 of two first welding marks 51. The third end 521 is spaced apart from the third welding mark 53.

[0248] The two first welding imprints 51 and the third welding imprint 53 are integrated, which can increase the current-carrying area and reduce the temperature rise of the cylindrical battery cell 7 during cycling. Compared with the solution of forming two first welding imprints 51 in two welding processes, in the embodiment of the present application, the two first welding imprints 51 and the third welding imprint 53 can be completed in one welding process, thereby reducing the risk of welding explosion points and improving the welding efficiency.

[0249] In some embodiments, at least a part of the third welding imprint 53 is arc-shaped. The arc shape can make the transition of the welding direction smoother, reduce the risk of welding explosion points, and improve the welding quality.

[0250] In some embodiments, the two first welding imprints 51 and the third welding imprint 53 approximately form a U-shaped welding imprint.

[0251] Figure 11 Schematic diagram of the electrode assembly and the current collector member provided in still other embodiments of the present application; Figure 12 is Figure 11 A cross-sectional schematic diagram taken along the A-A direction; Figure 13 is Figure 12 An enlarged schematic diagram at the circular frame.

[0252] Referring to Figures 11 to 13 , in some embodiments, a plurality of recesses 43 are provided on the side of the current collector member 40 facing away from the first tab 12, and the plurality of recesses 43 are arranged at intervals along the circumferential direction V of the current collector member 40. The bottom wall of each recess 43 is welded to the first tab 12 to form a welding imprint group 50.

[0253] During welding, the recesses 43 can be used for positioning, facilitating the welding equipment to capture the welding position and improving the welding efficiency. An external device can press against the non-recessed area of the current collector member 40 to make the current collector member 40 fit with the first tab 12 during welding, reducing the risk of false soldering.

[0254] In some embodiments, a plurality of protrusions 44 are provided on the side of the current collector member 40 facing the first tab 12, and the plurality of protrusions 44 are arranged in one-to-one correspondence with the plurality of recesses 43. The bottom wall of the recess 43 can be the part of the current collector member 40 located between the top surface of the protrusion 44 and the bottom surface of the recess 43.

[0255] The protrusions 44 can abut against the first tab 12. When the current collector member 40 is pressed, due to the smaller area of the protrusions 44, it is easier for the protrusions 44 to fit with the first tab 12, thereby reducing the gap between the first tab 12 and the bottom wall of the recess 43 and reducing the risk of false soldering.

[0256] Figure 14 Schematic diagram of the electrode assembly and the current collector member provided in some embodiments of the present application.

[0257] The current collecting member 40 is provided with a channel 45 that penetrates the current collecting member 40 along the thickness direction of the current collecting member 40. On the circumferential direction V of the current collecting member 40, at least a part of the channel 45 is located between adjacent weld mark groups 50.

[0258] The channel 45 can be strip-shaped, circular, rectangular or other shapes.

[0259] When the cylindrical battery cell 7 undergoes thermal runaway accidentally, the substances generated by the reaction of the electrode assembly 10 can pass through the current collecting member 40 via the channel 45, and thus be discharged to the outside of the housing 20 in time, reducing the explosion risk. By using the part of the current collecting member 40 located between the weld mark groups 50 to form the channel 45, the current-carrying capacity and the exhaust capacity of the current collecting member 40 can be taken into account.

[0260] In some embodiments, the cylindrical battery cell 7 includes a pressure relief mechanism disposed on the housing 20. Exemplarily, the pressure relief mechanism is located on the side of the current collecting member 40 away from the first tab 12.

[0261] In some embodiments, the channel 45 includes a linear channel 451 extending linearly. Optionally, the linear channel 451 extends along the radial direction of the current collecting member 40.

[0262] In some embodiments, the channel 45 includes a plurality of linear channels 451, and the plurality of linear channels 451 and the plurality of weld mark groups 50 are alternately arranged along the circumferential direction V of the current collecting member 40.

[0263] In some embodiments, the channel 45 includes a first hole 452 located in the middle of the current collecting member 40, and the central axis C passes through the first hole 452. Optionally, the first hole 452 is a square hole or a circular hole.

[0264] The aperture of the first hole 452 is larger than the width of the linear channel 451.

[0265] Exemplarily, for a non-circular hole, the aperture is the diameter of the circumscribed circle of the non-circular hole.

[0266] In some embodiments, the first hole 452 communicates with at least two linear channels 451.

[0267] In some embodiments, the channel 45 further includes a second hole 453, and the second hole 453 is located between adjacent weld mark groups 50 in the circumferential direction V of the current collecting member 40.

[0268] In some embodiments, the second hole 453 communicates with one end of the linear channel 451 away from the central axis C. The aperture of the second hole 453 is larger than the width of the linear channel 451.

[0269] In some embodiments, a part of the linear channels 451 communicate with the first hole 452, and another part of the linear channels 451 communicate with the second hole 453.

[0270] In some embodiments, there are four linear channels 451. Two linear channels 451 are on an integral straight line, and the first hole 452 is located between these two linear channels 451. The remaining two linear channels 451 are arranged at intervals from the first hole 452, and a second hole 453 is provided at one end of each linear channel 451 away from the first hole 452.

[0271] According to some embodiments of the present application, the present application further provides a battery, including a plurality of cylindrical battery monomers 7 as in any of the above embodiments.

[0272] According to some embodiments of the present application, the present application further provides an electrical device, including the cylindrical battery monomer 7 as in any of the above embodiments, and the cylindrical battery monomer 7 is used to provide electrical energy for the electrical device. The electrical device can be any of the aforementioned devices or systems that apply the cylindrical battery monomer 7.

[0273] Referring to Figures 4 to 9 , an embodiment of the present application provides a cylindrical battery monomer 7, which includes a housing 20, an electrode terminal 30, an electrode assembly 10, and two current collecting members 40.

[0274] The electrode assembly 10 is accommodated in the housing 20. The electrode assembly 10 is of a wound structure and includes an electrode body 11, a first tab 12, and a second tab 13. The first tab 12 and the second tab 13 have opposite polarities and are respectively led out from both ends of the electrode body 11.

[0275] The housing 20 includes a housing body 21 and an end cover 22. The housing body 21 has an opening, and the end cover 22 is used to cover the opening; the housing body 21 includes an end wall 211 and a side wall 212. The end wall 211 is disposed opposite to the end cover 22, and the side wall 212 surrounds the end wall 211 and connects the end wall 211 and the end cover 22. The electrode terminal 30 is disposed on the end wall 211.

[0276] One of the electrode terminal 30 and the end wall 211 is electrically connected to the first tab 12 through the current collecting member 40, and the other is electrically connected to the second tab 13.

[0277] The current collecting member 40 is located on a side of the first tab 12 away from the electrode body 11. The current collecting member 40 is welded to the first tab 12 and forms a plurality of weld mark groups 50, and the plurality of weld mark groups 50 are arranged at intervals along the circumferential direction V of the current collecting member 40. Optionally, along the circumferential direction V of the current collecting member 40, the plurality of weld mark groups 50 can be arranged at equal angular intervals.

[0278] Each weld mark group 50 includes two first weld marks 51 and one second weld mark 52, and the first weld marks 51 and the two second weld marks 52 all extend along the radial direction of the current collecting member 40. On the circumferential direction V of the current collecting member 40, the second weld mark 52 is located between the two first weld marks 51.

[0279] In the direction pointing from the outside of the electrode assembly 10 towards the central axis C of the electrode assembly 10, the first welding mark 51 and the second welding mark 52 extend linearly. The first welding mark 51 has a first end 511 close to the central axis C and a second end 512 far from the central axis C. The second welding mark 52 has a third end 521 close to the central axis C and a fourth end 522 far from the central axis C. The extension length L1 of the first welding mark 51 is greater than the extension length L2 of the second welding mark 52, and the distance between the third end 521 and the second end 512 is less than the distance between the third end 521 and the first end 511.

[0280] The current collecting member 40 includes a first sector area 41 and a second sector area 42. In the circumferential direction V of the current collecting member 40, the first sector area 41 is located between two first welding marks 51 of the welding mark group 50, and the second sector area 42 is located between adjacent welding mark groups 50. The central angle of the second sector area 42 is greater than the central angle of the first sector area 41.

[0281] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0282] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features, but these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

[0283] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0284] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features, but these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A cylindrical battery cell, characterized in that: include: shell; A first electrode lead-out portion is disposed on the housing; An electrode assembly is contained in the housing, wherein the electrode assembly is a winding structure and includes an electrode body and a first electrode tab extending from an end of the electrode body; a current collecting member, electrically connected to the first electrode lead-out portion, the current collecting member being located on a side of the first electrode tab away from the electrode body, the current collecting member being welded to the first electrode tab to form a plurality of weld mark groups, the plurality of weld mark groups being arranged at intervals along the circumference of the current collecting member; Each of the weld print groups includes at least one first weld print and at least one second weld print, and the first weld print and the second weld print extend linearly in the direction of the center axis of the electrode assembly from the outside of the electrode assembly, the first weld print has a first end close to the center axis and a second end away from the center axis, and the second weld print has a third end close to the center axis and a fourth end away from the center axis; The extension length of the first weld mark is greater than the extension length of the second weld mark, and the distance between the third end and the second end is less than the distance between the third end and the first end.

2. The cylindrical battery cell according to claim 1, characterized in that: The first weld mark and the second weld mark both extend along a straight line.

3. The cylindrical battery cell according to claim 1, characterized in that: The first weld mark extends in a radial direction of the current collecting member; and / or The second weld mark extends in a radial direction of the current collecting member.

4. The cylindrical battery cell according to claim 1, characterized in that: The weld print group includes two of the first weld prints.

5. The cylindrical battery cell according to claim 4, characterized in that: In the circumferential direction of the current collecting member, the third end is located between two adjacent first weld marks.

6. The cylindrical battery cell according to claim 4, characterized in that: In the circumferential direction of the current collecting member, the fourth end is located between two adjacent first weld marks.

7. The cylindrical battery cell according to claim 4, characterized in that: The welding print group further includes a third welding print, wherein the third welding print connects the first ends of the two first welding prints; The third end is spaced apart from the third weld mark.

8. The cylindrical battery cell according to claim 7, characterized in that: At least a portion of the third weld mark is in an arc shape.

9. The cylindrical battery cell according to claim 4, characterized in that: The first weld mark extends along the radial direction of the current collecting component; The current collecting component comprises a first sector-shaped area and a second sector-shaped area. In the circumferential direction of the current collecting component, the first sector-shaped area is located between two first weld marks of the weld mark group, and the second sector-shaped area is located between adjacent weld mark groups. The central angle of the second sector area is greater than the central angle of the first sector area.

10. The cylindrical battery cell according to claim 1, characterized in that: The ratio of the extension length of the second weld mark to the extension length of the first weld mark is 0.1-0.

5.

11. The cylindrical battery cell according to claim 1, characterized in that: A minimum distance between the fourth end and the central axis is less than or equal to a minimum distance between the second end and the central axis.

12. The cylindrical battery cell according to claim 1, characterized in that: In the circumferential direction of the current collecting component, the maximum distance between two adjacent weld print groups is greater than the maximum size of the weld print groups.

13. The cylindrical battery cell according to claim 1, characterized in that: A plurality of recesses are provided on a side of the current collecting component away from the first electrode tab, and the plurality of recesses are arranged at intervals along the circumference of the current collecting component; The bottom wall of each recess is welded to the first electrode tab to form the weld mark group.

14. The cylindrical battery cell according to claim 1, characterized in that: At least a portion of the first electrode lead-out portion is located on a side of the current collecting member away from the first electrode tab and abuts against the current collecting member; The plurality of weld print groups are arranged along the outer circumference of the first electrode lead-out portion, and each of the weld print groups is spaced apart from the first electrode lead-out portion.

15. The cylindrical battery cell according to claim 1, characterized in that: The width of the second weld mark is 0.5 to 2 times the width of the first weld mark.

16. The cylindrical battery cell according to claim 1, characterized in that: A minimum spacing between the third end and the first weld mark is greater than or equal to 0.5 times the width of the first weld mark.

17. The cylindrical battery cell according to claim 1, characterized in that: The first pole tab is wound to form N windings, and the second weld mark is connected to the M windings, 0.05≤M / N≤0.

4.

18. The cylindrical battery cell according to claim 1, characterized in that: The housing includes a wall portion, and the first electrode lead portion is an electrode terminal insulated and arranged on the wall portion; or The housing includes a shell and an end cover, the shell has an opening, the end cover covers the opening, and the first electrode lead-out portion is at least a part of one of the shell and the end cover.

19. The cylindrical battery cell according to claim 1, characterized in that: The current collecting component is provided with a channel, and the channel penetrates the current collecting component along the thickness direction of the current collecting component; In the circumferential direction of the current collecting member, at least a portion of the channel is located between adjacent weld print groups.

20. The cylindrical battery cell according to claim 1, characterized in that: The height of the housing is 1.3 to 4 times the diameter of the housing.

21. The cylindrical battery cell according to claim 1, characterized in that: The height of the housing is 50 mm to 150 mm; and / or The diameter of the shell is 40 mm to 80 mm.

22. A battery, characterized in that: The invention comprises a plurality of cylindrical battery cells according to any one of claims 1 to 21.

23. An electrical device, characterized in that: A battery according to claim 22, for providing electrical energy.

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