Battery monomer, battery, power utilization device and preparation device of battery monomer

Abstract

According to the battery monomer, the battery, the power utilization device and the preparation device of the battery monomer provided by the invention, tabs are flattened at different depths, so that the tabs form two areas with depth fall from inside to outside, namely the first flattening part and the second flattening part. And meanwhile, the second rubbing part of the outer ring is controlled to be lower than the first rubbing part of the inner ring, so that after the electrode assembly is packaged in the shell, the second rubbing part close to the inner wall of the shell is located at a lower position. At the moment, even if the second rubbing part tilts due to internal accumulated elastic force, the second rubbing part cannot bypass the circumferential structure of the tab, such as the top of the first insulating part, and is lapped on the inner wall of the shell. Therefore, the risk of electrochemical corrosion caused by lap joint of the tab and the shell is effectively reduced, so that the phenomenon of liquid leakage of the single battery is reduced, and the reliability is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to battery cells, batteries, electrical devices, and apparatus for preparing battery cells. Background Technology

[0002] Electrode assemblies are the components within a battery cell where electrochemical reactions occur. They are primarily formed by winding or stacking positive and negative electrode plates, typically with a separator between the positive and negative electrode plates. During winding, electrode assemblies can have flat or cylindrical structures. For cylindrical electrode assemblies, the battery cell is at risk of corrosion and leakage during use, severely impacting the battery cell's reliability. Summary of the Invention

[0003] Therefore, it is necessary to provide a battery cell, a battery, an electrical device, and an apparatus for preparing a battery cell, which can effectively reduce the risk of corrosion and leakage in the battery cell and improve the reliability of the battery cell.

[0004] In a first aspect, this application provides a battery cell including an electrode assembly. The electrode assembly includes a main body and a tab disposed at at least one end of the main body along a preset direction. The tab includes a first flattened portion and a second flattened portion, the second flattened portion surrounding the outer periphery of the first flattened portion, and the first flattened portion protruding from the second flattened portion along the preset direction.

[0005] The aforementioned electrode assembly features tabs that have been flattened to varying depths, creating two distinct flattened regions from the inside out: a first flattened portion and a second flattened portion. Simultaneously, the second flattened portion on the outer ring is positioned lower than the first flattened portion on the inner ring. This ensures that when the electrode assembly is encapsulated within the housing, the second flattened portion near the inner wall of the housing is at a lower position. Even if the second flattened portion tilts upwards due to internal elastic force, it cannot bypass the circumferential structures of the tab, such as the top of the first insulating component, and overlap with the inner wall of the housing. This effectively reduces the risk of electrochemical corrosion caused by the tab overlapping with the housing, thereby reducing battery cell leakage and improving reliability.

[0006] In some embodiments, the density of the first flattened portion is denoted as Q1, and the density of the second flattened portion is denoted as Q2. The condition that Q1 and Q2 satisfy is: Q2 > Q1. In this way, the density of the second flattened portion is higher than that of the first flattened portion, so that the portion of the tab near the outer ring is flattened to a higher degree and is less likely to warp, effectively reducing the risk of electrochemical corrosion caused by the tab warping and overlapping with the shell at that location.

[0007] In some embodiments, Q1 and Q2 also satisfy the condition that 105% ≤ Q2 / Q1 ≤ 140%. Thus, by reasonably controlling the ratio of Q2 / Q1, the risk of the second flattened part warping and overlapping with the shell can be effectively reduced; at the same time, it also reduces structural damage to the tabs.

[0008] In some embodiments, Q1 / Q2 also satisfies the condition that 105% ≤ Q2 / Q1 ≤ 130%. In this way, by further reasonably controlling the ratio of Q2 / Q1, the risk of the second flattened part warping and overlapping with the shell can be reduced, and the damage to the tab structure caused by excessive flattening of the second flattened part can be effectively reduced.

[0009] In some embodiments, the height by which the first flattened portion protrudes beyond the second flattened portion along a preset direction is denoted as h1, where 1mm ≤ h1 ≤ 4mm. This controls the height difference between the first and second flattened portions to be between 1mm and 4mm, resulting in the second flattened portion being lower, thus making it less likely for the protruding second flattened portion to overlap the inner wall of the housing.

[0010] In some embodiments, h1 also satisfies the condition that 1mm ≤ h1 ≤ 2.5mm. Thus, by further rationally controlling the value of h1, the risk of the second flattened portion warping and overlapping with the shell is reduced, while effectively minimizing damage to the electrode tab caused by excessive flattening of the second flattened portion.

[0011] In some embodiments, the second flattening portion includes an inner edge adjacent to the first flattening portion and an outer edge surrounding the inner edge, the distance between the inner edge and the outer edge being denoted as L, where 1mm≤L≤5mm. Thus, by reasonably controlling the value of the distance L, the risk of the tab warping and overlapping with the housing is reduced, while ensuring that the first flattening portion has a reasonable welding area to improve current carrying capacity.

[0012] In some embodiments, L also satisfies the condition: 1mm≤L≤3mm. Thus, by further rationally controlling the value of L, the welding area of ​​the first flattened portion is maximized while effectively reducing the risk of the tab warping and overlapping with the housing, thereby further improving the current-carrying capacity.

[0013] In some embodiments, the second flattened portion includes an inner edge adjacent to the first flattened portion and an outer edge surrounding the inner edge, the distance between the inner edge and the outer edge being denoted as L; the height by which the first flattened portion protrudes from the second flattened portion along a predetermined direction is denoted as h1, and the condition that L and h1 must satisfy is: L > h1. Thus, by controlling the height h1 to be less than the distance L, even if the first flattened portion bends, it cannot extend beyond the second flattened portion and overlap with the shell, effectively reducing the probability of corrosion and leakage caused by the first flattened portion overlapping with the shell.

[0014] In some embodiments, the electrode assembly is configured as a cylindrical structure. Along the radial direction of the electrode assembly, the outer diameter of the electrode assembly at the main body is denoted as Y, and half the difference between the outer and inner diameters of the second flattened portion is denoted as L. The condition satisfied between Y and L is: ≤L≤ Thus, by establishing an inequality relationship between Y and L, the parameters of the two are correlated, so as to achieve the optimal value of L for battery cells of different diameters, which neither affects the flow area of ​​the first flattened part nor reduces the probability of the tabs sticking up and overlapping onto the casing.

[0015] In some embodiments, the electrode assembly includes a diaphragm, with a first flattening portion and a second flattening portion both protruding from the diaphragm along a predetermined direction. This arrangement, where both the first and second flattening portions protrude from the diaphragm, reduces the possibility of the electrode tabs damaging the diaphragm during flattening.

[0016] In some embodiments, the battery cell further includes: a housing having an opening and housing an electrode assembly therein, with tabs facing the corresponding opening; and a first insulating member located inside the housing and surrounding the outer periphery of the second flattened portion, protruding from the second flattened portion in a predetermined direction.

[0017] In some embodiments, the height by which the first insulating member protrudes beyond the second flattened portion along a preset direction is denoted as h2, where 7mm ≤ h2 ≤ 15mm. Thus, by reasonably controlling the value of the height h2, the possibility of the fully raised second flattened portion overlapping the housing and causing corrosion and leakage can be reduced; and the waste of space above the second flattened portion can also be minimized.

[0018] In some embodiments, h2 also satisfies the condition: 10mm ≤ h2 ≤ 15mm. Thus, increasing the lower limit of h2 makes the protruding portion of the first insulating member more likely to overlap with the raised second flattened portion and the housing.

[0019] In some embodiments, the first insulating member protrudes beyond the first flattened portion in a predetermined direction. This design, where the first insulating member protrudes beyond the first flattened portion, not only enhances protection at the second flattened portion but also improves protection at the first flattened portion.

[0020] In some embodiments, the battery cell further includes an end cap assembly covering the opening, with the first insulating member in contact with the end cap assembly. This design, which places the end cap assembly and the first insulating member in contact in a predetermined direction, effectively prevents the first or second flattened portion from extending and warping along a direction perpendicular to the predetermined direction, greatly reducing the likelihood of the tab warping and overlapping with the housing.

[0021] In some embodiments, the end cap assembly includes an end cap and a second insulating member. The end cap covers the opening, and the second insulating member is disposed on the side of the end cap facing the electrode assembly. A first insulating member surrounds at least a portion of the outer periphery of the second insulating member and contacts the second insulating member. Thus, by rationally designing the structure of the second insulating member and the mating relationship between the first and second insulating members, the probability of the raised first or second flattened portion overlapping the casing can be effectively reduced, thereby lowering the risk of corrosion and leakage of the battery cells.

[0022] In some embodiments, at least a portion of the second insulating member surrounds the outer periphery of the first flattened portion. This further enhances protection at the first flattened portion, reduces the risk of the first flattened portion overlapping the casing, and thus improves the reliability of the battery cell.

[0023] In some embodiments, the end of the second insulating member away from the end cap is located within the enclosure of the first insulating member, and the distance between the second insulating member and the end of the first insulating member facing the end cap in a predetermined direction is denoted as h3, where 3mm ≤ h3 ≤ 8mm. Thus, by reasonably controlling the distance h3 between the first and second insulating members, the possibility of the raised first or second flattened portion protruding through the gap between the first and second insulating members and overlapping the housing can be effectively reduced.

[0024] In some embodiments, the first insulating member is bonded to the circumferential side of the second insulating member. This design ensures a stable bond between the two and effectively reduces the risk of the raised first or second flattened portion widening the gap between the first and second insulating members and causing overlap of the housing.

[0025] In some embodiments, the end cap assembly includes electrode terminals, and the second insulating member includes a body and an extension connected to each other. The body is located between the end cap and the electrode terminals, and the extension extends from the body toward the electrode assembly and surrounds the outer periphery of the first flattened portion. This design reduces the possibility that the first flattened portion may be compressed and deformed during assembly due to the second insulating member pressing the first flattened portion in a predetermined direction.

[0026] Secondly, this application provides a battery comprising any of the above-mentioned battery cells.

[0027] Thirdly, this application provides an electrical device including any of the batteries described above, the batteries being used to provide electrical energy.

[0028] Fourthly, this application provides a method for preparing a battery cell, comprising the following steps: providing an electrode assembly; flattening the tabs of the electrode assembly to different depths to form a first flattened portion and a second flattened portion surrounding the first flattened portion, wherein the first flattened portion protrudes from the second flattened portion along a predetermined direction of the electrode assembly.

[0029] The aforementioned method for preparing a battery cell involves flattening the tabs to different depths, creating a first flattened portion and a second flattened portion with a depth difference. When the prepared electrode assembly is encapsulated within the housing, the second flattened portion, closer to the inner wall of the housing, is positioned lower. Even if the second flattened portion tilts upwards due to internal elastic force, it cannot bypass the circumferential structure of the tab and overlap with the inner wall of the housing. This effectively reduces the risk of electrochemical corrosion caused by the tab overlapping with the housing, thereby reducing battery cell leakage and improving reliability.

[0030] Fifthly, this application provides a battery cell manufacturing apparatus, comprising: a driving mechanism; a flattening wheel driven by the driving mechanism and rotating around its own axis; wherein the flattening wheel includes a wheel body and a flattening protrusion, the flattening protrusion being disposed on the flattening surface of the wheel body and extending circumferentially around the wheel body.

[0031] The aforementioned battery cell fabrication apparatus features an annularly designed flattening protrusion on the flattening surface of the rolling wheel. During the flattening process, the flattening protrusion preferentially acts on the tabs. After flattening to a certain depth, the flattening surface then contacts and flattens the inner ring area of ​​the tab. Thus, using this flattening wheel, the tab can form a first flattening section and a second flattening section with a depth difference. When the fabricated electrode assembly is encapsulated in the housing, the second flattening section, closer to the inner wall of the housing, is in a lower position. At this point, even if the second flattening section tilts upwards due to internal accumulated elastic force, it cannot overlap with the inner wall of the housing. This effectively reduces the risk of electrochemical corrosion caused by the tab overlapping with the housing, thereby reducing battery cell leakage and improving reliability.

[0032] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0033] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0034] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0035] Figure 2 This is an exploded view of the battery structure provided in some embodiments of this application;

[0036] Figure 3 These are structural cross-sectional views of a battery cell provided in some embodiments of this application;

[0037] Figure 4 This is a schematic diagram of the structure of a battery cell provided in some embodiments of this application;

[0038] Figure 5 This is a schematic diagram of the structure of an electrode assembly provided in some embodiments of this application;

[0039] Figure 6 for Figure 5A partial structural diagram of the middle electrode assembly;

[0040] Figure 7 for Figure 6 Enlarged schematic diagram of the structure at point A in the middle circle;

[0041] Figure 8 Partial structural diagrams of electrode assemblies provided for other embodiments of this application;

[0042] Figure 9 A flowchart illustrating a method for preparing a battery cell according to some embodiments of this application;

[0043] Figure 10 This is a schematic diagram of the structure of a kneading roller provided in some embodiments of this application.

[0044] 1000, Vehicle; 100, Battery; 101, Bottom casing; 102, Top cover; 200, Controller; 300, Motor; 400, Battery Module; 401, Housing; 40a, Cylindrical Body; 40b, First Cover; 40c, Second Cover; 10, Battery Cell; 11, Housing; 111, Opening; 12, Electrode Assembly; 121, Main Body; 122, End; 13, Tab; 131, First Flattening Part; 132, Second Flattening Part; 13a, Inner Edge; 13b, Outer Edge; 14, End Cap Assembly; 141, End Cap; 142, Second Insulator; 14a, Body; 14b, Extension; 14c, Guide Surface; 14d, Recess; 143, Electrode Terminal; 15, Adapter; 16, First Insulator; 17, Diaphragm; 20, Flattening Roller; 21, Roller Body; 22, Flattening Surface; 23, Flattening Protrusion; X, Preset Direction; Z, Radial. Detailed Implementation

[0045] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0047] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0048] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0049] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0050] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0051] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "length direction," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0052] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0053] Currently, judging from market trends, the application of power batteries is becoming increasingly widespread. Power batteries are not only used in energy storage systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as in military equipment and aerospace. With the continuous expansion of power battery applications, market demand is also constantly increasing.

[0054] The applicant has noted that, to facilitate the assembly of battery cells, such as welding adapters to tabs, the end faces of the tabs are typically flattened to increase the welding area. However, the flattened tabs accumulate elastic force. During battery cell assembly, the tabs do not immediately lift due to this accumulated elastic force. Instead, after the battery cell has been used for a period of time, the tabs will lift due to the accumulated elastic force, overlapping with the inner wall of the casing, leading to electrochemical corrosion and leakage. For example, electrochemical corrosion can cause an increase in voltage or current within the battery cell, making it easier for pressure relief mechanisms (such as explosion-proof membranes) on the battery cell to be punctured, thus causing leakage.

[0055] To reduce the risk of the raised tabs overlapping with the inner wall of the housing, a first insulating element (such as tab adhesive) is attached to the outer periphery of the tab to prevent it from overlapping with the housing. However, this solution is not effective; some tabs will still bend over the top of the first insulating element and overlap with the inner wall of the housing, especially the part of the tabs closest to the inner wall of the housing.

[0056] Based on this, to address the persistent corrosion and leakage issues in traditional battery cells, the applicant, after in-depth research, designed a new battery cell. The tabs are flattened to varying depths, creating two distinct areas with a depth difference from the inside out, with the second flattened area lower than the first. This ensures that when the electrode assembly is encapsulated within the housing, the second flattened area, closer to the inner wall of the housing, is positioned lower. Even if the second flattened area tilts upwards due to internal elastic force, it cannot bypass the top of the first insulating component and overlap with the inner wall of the housing. This effectively reduces the risk of electrochemical corrosion caused by the tabs overlapping with the housing, thereby reducing battery cell leakage and improving reliability.

[0057] In addition, the flattening design at different depths reduces the chance of the tabs sticking up and overlapping with the casing, which also helps to solve the problem of short circuits in individual battery cells during use.

[0058] The battery cells disclosed in this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft. A power system for such an electrical device can be constructed using battery cells and batteries disclosed in this application.

[0059] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0060] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0061] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery 100 is disposed inside the vehicle 1000, and the battery 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000; for example, the battery 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0062] In some embodiments of this application, the battery 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0063] The battery 100 includes a housing. The type of housing is not limited. The housing can be a frame-shaped housing, a disc-shaped housing, or a box-shaped housing, etc. The battery 100 can be designed directly as a module-less structure, or it can be designed as a battery module 400 structure, etc. Exemplarily, the housing includes a bottom shell 101 and a top cover 102 that covers the bottom shell 101. The bottom shell 101 and the top cover 102, when closed, form a receiving portion. The battery 100 includes multiple cylindrical battery cells 10, such as cylindrical battery cells, hexagonal prism battery cells, etc. A cylindrical battery cell refers to a battery cell 10 having a cylindrical shape. Multiple battery cells 10 can be assembled into the battery 100, or multiple battery cells 10 can first be assembled into a battery module 400, and then multiple battery modules 400 can be assembled into the battery 100. The figure schematically shows a battery module 400 of one embodiment, which is disposed within the receiving portion of the housing.

[0064] In some embodiments, to meet different power demands, the battery 100 may include multiple battery cells 10, wherein the multiple battery cells 10 may be connected in series, in parallel, or in a mixed configuration, where a mixed configuration refers to a combination of series and parallel connections. That is, multiple battery cells 10 may be directly disposed within the housing to form the battery 100.

[0065] See Figure 2 As shown, the battery 100 includes a housing 401 and a battery cell 10 disposed within the housing 401. In one example, the housing 401 includes a cylindrical body 40a, a first cover 40b, and a second cover 40c. The first cover 40b and the second cover 40c are respectively disposed at both ends of the cylindrical body 40a. The first cover 40b and the second cover 40c are detachably connected to the cylindrical body 40a. For example, the first cover 40b and the second cover 40c can be snapped onto the cylindrical body 40a or connected using screws. After assembly, the cylindrical body 40a, the first cover 40b, and the second cover 40c form a receiving space. The battery cell 10 is disposed within the receiving space of the housing 401.

[0066] See Figure 3 and Figure 4 As shown, the battery cell 10 of this embodiment includes a housing 11 and an electrode assembly 12 disposed within the housing 11. The housing 11 of this embodiment has a cylindrical structure. The housing 11 has an internal space for accommodating the electrode assembly 12 and electrolyte, and an opening 111 communicating with the internal space. The electrode assembly 12 can be inserted into the housing 11 through the opening 111. The housing 11 can be made of materials such as aluminum, aluminum alloy, or plastic. The electrode assembly 12 includes a tab 13. Along a predetermined direction X, the tab 13 is located at one end of the electrode assembly 12.

[0067] See Figure 4As shown, the battery cell 10 in this embodiment further includes an end cap assembly 14 and an adapter 15. The end cap assembly 14 includes an end cap 141, a second insulating member 142, and electrode terminals 143. The end cap 141 is a component that covers the opening 111 of the housing 11 to isolate the internal environment of the battery cell 10 from the external environment. The shape of the end cap 141 can be adapted to the shape of the housing 11 to fit the housing 11. Optionally, the end cap 141 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 141 is less prone to deformation under pressure and impact, enabling the battery cell 10 to have higher structural strength and improved safety performance. Functional components such as electrode terminals 143 can be provided on the end cap 141. The electrode terminals 143 can be used to electrically connect with the electrode assembly 12 for outputting or inputting electrical energy into the battery cell 10. In some embodiments, the end cap 141 may also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure, temperature, current, or voltage of the battery cell 10 reaches a threshold. The end cap 141 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this. In some embodiments, a second insulating member 142 may also be provided on the inner side of the end cap 141. The second insulating member 142 can be used to isolate the electrical connection components within the housing 11 from the end cap 141 to reduce the risk of short circuits. For example, the second insulating member 142 may be made of plastic, rubber, etc.

[0068] Electrode assembly 12 is the component in the battery cell 10 where the electrochemical reaction occurs. The casing 11 may contain one or more electrode assemblies 12. Electrode assembly 12 is typically formed by winding positive and negative electrode plates. Electrode assembly 12 can have a columnar structure, such as a cylinder or hexagonal prism, and a separator 17 is typically provided between the positive and negative electrode plates. Positive and negative electrode tabs can be located at opposite ends of the main body 121. During the charging and discharging process of the battery 100, the positive electrode tab 13 is electrically connected to the electrode terminal 143 to form a current loop.

[0069] Please refer to some embodiments of this application. Figure 5 This application provides a battery cell 10, which includes an electrode assembly 12. The electrode assembly 12 includes a main body portion 121 and a tab 13. The tab 13 is disposed at at least one end of the main body portion 121 along a predetermined direction X. The tab 13 includes a first flattened portion 131 and a second flattened portion 132. The second flattened portion 132 surrounds the outer periphery of the first flattened portion 131, and the first flattened portion 131 protrudes from the second flattened portion 132 along the predetermined direction X.

[0070] The electrode assembly 12 can be designed as a columnar structure, such as, but not limited to, a cylindrical, hexagonal prism, or other polyhedral prism structure. Meanwhile, the preset direction X can also be understood as the length direction of the electrode assembly 12.

[0071] The main body 121 refers to the part of the electrode assembly 12 used to generate electrical energy, such as the structure formed by winding the active material on the positive and negative electrode plates; the tab 13 refers to the part of the positive and negative electrode plates that is not coated with active material, and can also be understood as the end 122 of the main body 121 extending along a predetermined direction X.

[0072] The tabs 13 can be disposed at one end of the electrode assembly 12; or they can be disposed at opposite ends of the electrode assembly 12. When the tabs 13 are disposed at opposite ends of the electrode assembly 12, the positive and negative tabs are located at opposite ends of the electrode assembly 12, respectively. When the tabs 13 are disposed at one end of the electrode assembly 12, it means that both the positive and negative tabs 13 are located on the same side of the electrode assembly 12. In this case, care must be taken to distinguish the positive and negative tabs 13 on the same end during winding. For example, when winding the inner ring, the positive electrode sheet may have a positive tab, while the negative electrode sheet may not have a negative tab; when winding the outer ring, the positive electrode sheet may not have a positive tab, while the negative electrode sheet may have a negative tab, thus forming a situation where the middle part is the positive tab and the outer ring part is the negative tab, etc.

[0073] The first flattening section 131 and the second flattening section 132 refer to the middle and outer ring structures of the electrode tab 13, respectively. During the molding process, the end face of the electrode assembly 12 is flattened by a flattening method. Compared with the traditional cutting method, the end face of the flattened electrode tab 13 is flatter and denser, which facilitates the welding of the adapter 15 or electrode terminal 143 to the electrode tab 13 and also improves the strength of the welded structure.

[0074] The first kneading part 131 protrudes from the second kneading part 132, which means that the first kneading part 131 is higher than the second kneading part 132. During the kneading process, the kneading depth at the second kneading part 132 is relatively deeper.

[0075] After the electrode assembly 12 is encapsulated within the housing 11, the second flattened portion 132 near the inner wall of the housing 11 is in a lower position. At this time, even if the second flattened portion 132 is raised due to internal accumulated elastic force, it cannot bypass the circumferential structure of the tab 13, such as the top of the first insulating member 16, and overlap with the inner wall of the housing 11. This effectively reduces the risk of electrochemical corrosion caused by the tab 13 overlapping with the housing 11, thereby reducing leakage of the battery cell 10 and improving reliability.

[0076] According to some embodiments of this application, the density of the first kneaded portion 131 is denoted as Q1, and the density of the second kneaded portion 132 is denoted as Q2. The condition that Q1 and Q2 satisfy is: Q2 > Q1.

[0077] Density refers to the compaction density at the first flattened portion 131 or the second flattened portion 132. To obtain the density at the first flattened portion 131 and the second flattened portion 132, for the cylindrical electrode assembly 12, the following test method can be used, such as: 1. Density at the first flattened portion 131: Cut the first flattened portion 131 along the radial direction Z of the electrode assembly 12 and weigh it, recording the weight as m; measure the diameter d and thickness h of the cut first flattened portion 131; according to Q1= The formula is used for calculation; Second, the density of the second kneading part 132 is tested in a way that is similar to that of the first kneading part 131, except that the outer diameter and inner diameter of the second kneading part 132 need to be tested (i.e., the second kneading part 132 is a ring structure).

[0078] The density of the second flattened portion 132 is higher than that of the first flattened portion 131, which makes the outer part of the tab 13 more flattened and less prone to warping. This effectively reduces the risk of electrochemical corrosion caused by the tab 13 warping and overlapping with the shell 11.

[0079] According to some embodiments of this application, Q1 and Q2 also satisfy the condition that 105% ≤ Q2 / Q1 ≤ 140%.

[0080] The ratio of Q2 / Q1 can be a value between 105% and 140%, such as, but not limited to, 105%, 110%, 120%, 140%, etc. If Q2 / Q1 is too small, such as less than 105%, the flattening degree of the second flattening part 132 is equivalent to that of the first flattening part 131, and a large depth difference cannot be formed, causing the second flattening part 132 to easily lift up and overlap with the shell 11; if Q2 / Q1 is too large, such as greater than 140%, it means that the second flattening part 132 is over-flattened, which not only affects the assembly of the electrode assembly 12, but also easily damages the electrode tab 13 structure due to excessive flattening force.

[0081] By properly controlling the ratio of Q2 to Q1, the risk of the second flattening part 132 lifting up and overlapping with the shell 11 can be effectively reduced; at the same time, it also reduces structural damage to the tab 13.

[0082] According to some embodiments of this application, Q1 / Q2 also satisfies the condition: 105%≤Q2 / Q1≤130%.

[0083] The ratio of Q2 / Q1 can be a value between 105% and 130%, for example, Q2 / Q1 can be, but is not limited to, 105%, 110%, 120%, 130%, etc. Further limiting the upper limit of Q2 / Q1 can reduce the occurrence of over-kneading in the second kneading section 132.

[0084] Further reasonable control of the Q2 / Q1 ratio can reduce the risk of the second flattening part 132 lifting up and overlapping with the shell 11, and effectively reduce the damage to the electrode tab 13 structure caused by excessive flattening of the second flattening part 132.

[0085] Please refer to some embodiments of this application. Figure 5 Along the preset direction X, the height of the first kneading part 131 protruding from the second kneading part 132 is denoted as h1, where 1 mm ≤ h1 ≤ 4 mm.

[0086] The first flattened portion 131 protrudes from the second flattened portion 132, indicating that the second flattened portion 132 is lower than the first flattened portion 131. The height h1 of the second flattened portion 132 being lower than the first flattened portion 131 can be a value between 1 mm and 4 mm, for example, the height h1 can be, but is not limited to, 1 mm or 4 mm.

[0087] The height difference between the first flattened portion 131 and the second flattened portion 132 is controlled between 1 mm and 4 mm, so that the second flattened portion 132 is lower, making it less likely for the raised second flattened portion 132 to overlap with the inner wall of the shell 11.

[0088] Please refer to some embodiments of this application. Figure 5 h1 also satisfies the condition: 1mm≤h1≤2.5mm.

[0089] The height h1 of the second kneading section 132 below the first kneading section 131 can be a value between 1 mm and 2.5 mm. For example, the height h1 can be, but is not limited to, 1 mm or 2.5 mm. At the same time, the upper limit of h1 is restricted to limit the kneading descent of the second kneading section 132 from exceeding 2.5 mm, thereby reducing the risk of over-kneading.

[0090] Further reasonable control of the value of h1 can effectively reduce the damage to the tab 13 caused by excessive flattening of the second flattening part 132, while reducing the risk of the second flattening part 132 lifting up and overlapping with the shell 11.

[0091] Please refer to some embodiments of this application. Figure 5 The second kneading portion 132 includes an inner edge 13a adjacent to the first kneading portion 131 and an outer edge 13b surrounding the inner edge 13a. The distance between the inner edge 13a and the outer edge 13b is denoted as L, where 1mm≤L≤5mm.

[0092] The specific testing method for the spacing L can be determined according to the specific shape of the electrode assembly 12. For example, when the electrode assembly 12 is a cylindrical structure, the spacing L can be half the difference between the outer diameter and the inner diameter of the second flattened part 132 in the radial Z direction of the electrode assembly 12; or, when the electrode assembly 12 is another polygonal prism structure, the inner edge 13a and the outer edge 13b are both polygons. In this case, a perpendicular line can be drawn between the inner edge 13a and the outer edge 13b, and the length of the perpendicular line is the spacing L, etc.

[0093] The spacing L can be a value between 1mm and 5mm. For example, the spacing L can be, but is not limited to, 1mm or 5mm. If the spacing L is too small, the first flattened part 131 will be too close to the inner wall of the housing 11, which may cause the tab 13 to overlap with the housing 11. If the spacing L is too large, it will reduce the welding area between the first flattened part 131 and the adapter 15, affecting the current carrying capacity of the battery cell 10.

[0094] By reasonably controlling the value of the spacing L, the risk of the tab 13 warping and overlapping with the shell 11 is reduced, so that the first flattened part 131 has a reasonable welding area to improve the flow capacity.

[0095] Please refer to some embodiments of this application. Figure 5 L also satisfies the condition: 1mm≤L≤3mm.

[0096] The spacing L can be a value between 1mm and 3mm, for example, the spacing L can be, but is not limited to, 1mm or 3mm. At the same time, the upper limit of L is limited in order to increase the welding area between the first flattening part 131 and the adapter 15, and reduce the impact of the excessive flattening of the second flattening part 132 on the flow density of the electrode tab 13.

[0097] Further rationally control the value of L, and while effectively reducing the risk of the tab 13 warping and overlapping with the shell 11, increase the welding area of ​​the first flattened part 131 as much as possible to further improve the flow capacity.

[0098] According to some embodiments of this application, the second kneading portion 132 includes an inner edge 13a adjacent to the first kneading portion 131 and an outer edge 13b surrounding the inner edge 13a, the distance between the inner edge 13a and the outer edge 13b is denoted as L. Along a predetermined direction X, the height by which the first kneading portion 131 protrudes from the second kneading portion 132 is denoted as h1, and the condition that L and h1 also satisfy is: L > h1.

[0099] If the height h1 is greater than the spacing L, it means that when the first flattened portion 131 is bent toward the side of the second flattened portion 132, the bent first flattened portion 131 will at least partially extend beyond the second flattened portion 132 and overlap the housing 11.

[0100] Therefore, the height h1 is controlled to be less than the spacing L, so that even if the first flattening part 131 bends, it cannot extend beyond the second flattening part 132 and overlap with the shell 11, effectively reducing the probability of corrosion and leakage caused by the first flattening part 131 overlapping with the shell 11.

[0101] Please refer to some embodiments of this application. Figure 5 The electrode assembly 12 is constructed as a cylindrical structure. Along the radial direction Z of the electrode assembly 12, the outer diameter of the electrode assembly 12 at the main body 121 is denoted as Y. Half the difference between the outer diameter and inner diameter of the second flattened portion 132 is denoted as L. The condition that Y and L satisfy is: ≤L≤ .

[0102] When the electrode assembly 12 is a cylindrical structure, the inner edge 13a and the outer edge 13b on the second flattened portion 132 are two concentric circles. Therefore, half of the difference between the outer diameter and the inner diameter is the distance between the inner edge 13a and the outer edge 13b.

[0103] The value of L can be determined based on the outer diameter of the electrode assembly 12, such as: ≤L≤ In some examples, when the outer diameter of the cylindrical electrode assembly 12 is 46 mm, L can be 1.80 mm to 5.77 mm, and when the outer diameter of the cylindrical electrode assembly 12 is 34 mm, L can be 0.82 mm to 3.46 mm, etc.

[0104] By establishing an inequality relationship between Y and L, the parameters of the two are correlated, so as to achieve the optimal value of L for battery cells 10 with different diameters. This not only does not affect the flow area of ​​the first flattened part 131, but also reduces the probability of the tab 13 sticking up and overlapping the shell 11.

[0105] Please refer to some embodiments of this application. Figure 5 The electrode assembly 12 includes a diaphragm 17, and the first kneading portion 131 and the second kneading portion 132 are both protruding from the diaphragm 17 along a preset direction X.

[0106] The separator 17 is a porous plastic film that allows lithium ions to pass freely to form a circuit, while preventing the two electrodes from contacting each other and providing electronic insulation. It can be, but is not limited to, a polyethylene monolayer film or a polypropylene monolayer film. In some embodiments, in a predetermined direction X, the separator 17 is generally designed to extend beyond the positive and negative electrode plates, that is, the separator 17 may extend beyond the end 122 of the main body 121. The end 122 of the main body 121 can be understood as one end of the coating area of ​​the positive and negative electrode plates.

[0107] The first kneading portion 131 and the second kneading portion 132 are both set to protrude from the diaphragm 17, which can reduce the risk of the tab 13 damaging the diaphragm 17 during kneading.

[0108] Please refer to some embodiments of this application. Figure 3 and Figure 6 The battery cell 10 also includes a housing 11 and a first insulating member 16. The housing 11 has an opening 111 and an electrode assembly 12 is housed therein, with tabs 13 facing the corresponding opening 111. The first insulating member 16 is located inside the housing 11 and surrounds the outer periphery of the second flattened portion 132, and protrudes from the second flattened portion 132 in a predetermined direction X.

[0109] The housing 11 is a component used to form the internal environment of a single cell of the battery 100, wherein the formed internal environment can accommodate the electrode assembly 12, the electrolyte, and other components. The housing 11 may have one or two openings 111. When there are two openings 111, the two openings 111 are respectively located at opposite ends of the housing 11 along a predetermined direction X. Simultaneously, if there are two tabs 13, and the two tabs 13 are respectively located at both ends of the electrode assembly 12, the two tabs 13 are respectively oriented towards their corresponding openings 111.

[0110] The first insulating element 16 refers to a component that protects the second flattened portion 132 from direct contact with the inner wall of the housing 11 when the second flattened portion 132 is raised. The first insulating element 16 surrounds the second flattened portion 132 and has a closed annular structure. The material of the first insulating element 16 can be varied, for example, but not limited to, tab adhesive.

[0111] A first insulating element 16 is provided on the outer periphery of the second flattened portion 132 to effectively protect the second flattened portion 132 from warping, further reducing the possibility of corrosion and leakage caused by the tab 13 warping and overlapping on the housing 11.

[0112] Please refer to some embodiments of this application. Figure 6 and Figure 7 Along the preset direction X, the height of the first insulating member 16 protruding outside the second flattened part 132 is denoted as h2, where 7mm≤h2≤15mm.

[0113] The height of the first insulating member 16 protruding from the second flattened part 132 can be between 7mm and 15mm. For example, the height h2 can be, but is not limited to, 7mm or 15mm.

[0114] When designing the height h2, if the height h2 is too small, such as less than 7mm, the fully raised second flattened part 132 can bypass the top of the first insulating member 16 and overlap the housing 11; if the height h2 is too large, such as greater than 15mm, the space above the second flattened part 132 will be wasted.

[0115] Of course, when the first insulating part 16 is a tab adhesive, if the height h2 is too large, the height h2 will exceed the height of the tab adhesive itself, causing the tab adhesive to fail to adhere to the outer periphery of the second flattened part 132.

[0116] By properly controlling the value of height h2, the possibility of corrosion and leakage caused by the fully raised second flattened part 132 overlapping the shell 11 can be reduced; and the waste of space above the second flattened part 132 can also be reduced.

[0117] Please refer to some embodiments of this application. Figure 7 h2 also satisfies the condition: 10mm≤h2≤15mm.

[0118] The height h2 can be a value between 10mm and 15mm. For example, the height h2 can be, but is not limited to, 10mm or 15mm.

[0119] Increasing the lower limit of h2 makes the protruding portion of the first insulating member 16 more likely to overlap between the raised second flattened portion 132 and the housing 11.

[0120] Please refer to some embodiments of this application. Figure 7 The first insulating member 16 protrudes from the first flattened portion 131 in the preset direction X.

[0121] In addition to surrounding the second flattened portion 132, the first insulating member 16 also surrounds at least a portion of the first flattened portion 131. At this time, the first insulating member 16 also provides a certain degree of protection for the first flattened portion 131.

[0122] The design of the first insulating member 16 protruding from the first flattening part 131 not only helps to strengthen the protection of the second flattening part 132, but also helps to improve the protection of the first flattening part 131.

[0123] According to some embodiments of this application, the battery cell 10 further includes an end cap assembly 14 covering the opening 111. A first insulating member 16 contacts the end cap assembly 14.

[0124] The first insulating member 16 contacts the end cap assembly 14, which means that there will be no discontinuity between the end cap assembly 14 and the first insulating member 16 in the preset direction X. That is, when extending in a direction perpendicular to the preset direction X, it will either be blocked by the end cap assembly 14 or by the first insulating member 16.

[0125] The number of end cap assemblies 14 can be determined according to the opening 111. For example, when there are two openings 111, there are two end cap assemblies 14, and they are set one-to-one with the openings 111.

[0126] The design of contacting the end cap assembly 14 and the first insulating member 16 in the preset direction X can effectively prevent the first flattened part 131 or the second flattened part 132 from extending and lifting up along the preset direction X, greatly reducing the probability of the tab 13 overlapping with the housing 11 after it lifts up.

[0127] Please refer to some embodiments of this application. Figure 7 The end cap assembly 14 includes an end cap 141 and a second insulating member 142. The end cap 141 covers the opening 111, and the second insulating member 142 is disposed on the side of the end cap 141 facing the electrode assembly 12. A first insulating member 16 surrounds at least a portion of the outer periphery of the second insulating member 142 and contacts the second insulating member 142.

[0128] When the end cap 141 is placed on the opening 111, the end cap 141 and the housing 11 can be sealed and connected by welding, bonding or other methods to improve the airtightness of the battery cell 10.

[0129] The second insulating element 142 refers to a component used to isolate the electrical connection parts within the housing 11 from the end cap 141 to reduce the risk of short circuits, such as those made of plastic. The second insulating element 142 and the first insulating element 16 are designed to contact each other in a predetermined direction X, creating a relatively enclosed environment for the tab 13. Simultaneously, the second insulating element 142 and the first insulating element 16 may be interconnected or not connected, but merely in contact.

[0130] In addition, when the end of the second insulating member 142 away from the end cap 141 abuts against the second flattened portion 132, the first flattened portion 131 is completely closed by the second insulating member 142 and the second flattened portion 132, so that the first flattened portion 131 cannot overlap the housing 11.

[0131] By rationally designing the structure of the second insulating component 142 and the matching relationship between the first insulating component 16 and the second insulating component 142, the probability of the raised first flattened part 131 or the second flattened part 132 overlapping on the housing 11 can be effectively reduced, thereby reducing the risk of corrosion and leakage of the battery cell 10.

[0132] According to some embodiments of this application, optionally, at least a portion of the second insulating member 142 surrounds the outer periphery of the first flattened portion 131.

[0133] At least a portion of the second insulating member 142 surrounds the outer periphery of the first flattened portion 131, providing protection for the first flattened portion 131. In some examples, the side of the second insulating member 142 facing away from the end cap 141 has a recess 14d, in which the first flattened portion 131 is at least partially accommodated. This allows the first insulating member 16 to provide better protection for the first flattened portion 131, further reducing the risk of overlap between the first flattened portion 131 and the housing 11. Of course, in the preset direction X, the distance between the end face of the first flattened portion 131 and the bottom surface of the recess 14d can be controlled to be greater than or equal to 3 mm.

[0134] By surrounding at least a portion of the insulation element 142 with the outer periphery of the first flattened portion 131, the protection at the first flattened portion 131 can be further improved, the risk of the first flattened portion 131 overlapping the housing 11 can be reduced, and the reliability of the battery cell 10 can be improved.

[0135] Please refer to some embodiments of this application. Figure 6 The end of the second insulating member 142 away from the end cap 141 is located within the enclosure of the first insulating member 16, and the distance between the second insulating member 142 and the end of the first insulating member 16 facing the end cap 141 in the preset direction X is denoted as h3, 3mm≤h3≤8mm.

[0136] In addition to the overlapping portion of the projections of the second insulating member 142 and the first insulating member 16 in the preset direction X, the projections in the direction perpendicular to the preset direction X also overlap. Of course, this overlap may be related to the group margin of the electrode assembly 12, which will not be described in detail here.

[0137] The end of the second insulating member 142 away from the end cap 141 is located within the enclosure of the first insulating member 16. This means that in the preset direction X, one end of the second insulating member 142 extends into the enclosure of the first insulating member 16 and is lower than the end of the first insulating member 16 facing the end cap 141.

[0138] The distance h3 can be a value between 3mm and 8mm. For example, h3 can be, but is not limited to, 3mm or 8mm.

[0139] By properly controlling the distance h3 between the first insulating member 16 and the second insulating member 142, the possibility of the raised first flattened part 131 or the second flattened part 132 protruding through the gap between the first insulating member 16 and the second insulating member 142 and overlapping onto the shell 11 can be effectively reduced.

[0140] Please refer to some embodiments of this application. Figure 6The end cap assembly 14 includes an electrode terminal 143, and the second insulating member 142 includes a body 14a and an extension 14b connected to each other. The body 14a is located between the end cap 141 and the electrode terminal 143, and the extension 14b extends from the body 14a toward the electrode assembly 12 and surrounds the outer periphery of the first flattened portion 131.

[0141] The body 14a and the extension 14b refer to the upper portion structure of the second insulating member 142. The body 14a is disposed on the side of the end cap 141 facing the electrode assembly 12, while the extension 14b can also be understood as a structure formed by at least a portion of the body 14a protruding towards the electrode assembly 12. In some examples, a recess 14d may be formed between the body 14a and the extension 14b. The extension 14b is disposed on the outer periphery of the first flattened portion 131 of the tab 13 and corresponds to the position of the second flattened portion 132 along a predetermined direction X. Since the second insulating member 142 has the extension 14b, during assembly, the extension 14b of the second insulating member 142 can be inserted into the gap between the first flattened portion 131 and the housing 11, thereby the extension 14b can guide the first flattened portion 131 to be accurately inserted into the recess 14d of the second insulating member 142.

[0142] Additionally, the side of the extension 14b facing away from the recess 14d includes a guide surface 14c. Please refer to [reference needed]. Figure 7 and Figure 8 The guide surface 14c can abut against the first insulating member 16. The guide surface 14c extends in the direction away from the end cover 141 and is inclined toward the recess 14d. In this way, under the guidance of the guide surface 14c, a portion of the second insulating member 142 can easily enter the space defined by the first insulating member 16. This helps to reduce the probability that the second insulating member 142 directly presses against the first insulating member 16, causing the first insulating member 16 to collapse, thereby reducing the risk that the first insulating member 16 will lose its isolation function.

[0143] This design reduces the possibility that the first flattened portion 131 will be compressed and deformed during the assembly process due to the second insulating member 142 pressing the first flattened portion 131 along the preset direction X. At the same time, it also allows the extension portion 14b to provide better protection and limit the first flattened portion 131 during the assembly process.

[0144] Please refer to some embodiments of this application. Figure 6 The end of the first insulating member 16 facing the end cap 141 is bonded to the circumferential side of the second insulating member 142.

[0145] The circumferential side of the second insulating member 142 refers to the side of the second insulating member 142 facing the inner wall of the housing 11. Of course, in some embodiments, it includes the guide surface 14c on the extension 14b, etc.

[0146] By bonding the first insulating member 16 to the second insulating member 142, the two are stably combined, which can effectively reduce the risk that the raised first flattened part 131 or the second flattened part 132 will widen the gap between the first insulating member 16 and the second insulating member 142 and overlap the shell 11.

[0147] According to some embodiments of this application, this application provides a battery 100, including any of the above-mentioned battery cells 10.

[0148] According to some embodiments of this application, this application provides an electrical device including a battery 100 as described above, the battery 100 being used to provide electrical energy.

[0149] Please refer to some embodiments of this application. Figure 9 This application provides a method for preparing a single battery cell, comprising the following steps:

[0150] S100, Provides electrode assembly 12;

[0151] S200, the tabs 13 of the electrode assembly 12 are flattened to different depths to form a first flattened portion 131 and a second flattened portion 132 surrounding the first flattened portion 131, wherein the first flattened portion 131 protrudes from the second flattened portion 132 along a preset direction X of the electrode assembly 12.

[0152] In step S100, the electrode assembly 12 can be provided in various ways, such as by manufacturing it through a winding process or by purchasing it directly. The electrode assembly 12 of this application can be cylindrical, hexagonal prism, or other columnar structures.

[0153] In step S200, different areas of the tab 13 are kneaded to different depths. For example, the inner ring area of ​​the tab 13 is kneaded shallower, while the outer ring area is kneaded deeper. The kneading of different areas of the tab 13 can be performed simultaneously or in stages. For example, the inner ring area of ​​the tab 13 can be kneaded first, followed by the outer ring area; or the outer ring area can be kneaded first, followed by the inner ring area.

[0154] In addition, the method for preparing a single battery cell may include the following steps: welding the end cap assembly 14 onto the flattened first flattened portion 131; surrounding the second flattened portion 132 with the first insulating member 16; inserting the electrode assembly 12 into the housing 11 and covering the housing 11 with the end cap assembly 14, such that the second insulating member 142 of the end cap assembly 14 abuts against the first insulating member 16.

[0155] The aforementioned method for preparing a battery cell involves flattening the tab 13 to different depths, resulting in a first flattened portion 131 and a second flattened portion 132 with a depth difference. When the prepared electrode assembly 12 is encapsulated within the housing 11, the second flattened portion 132, closer to the inner wall of the housing 11, is positioned lower. Even if the second flattened portion 132 tilts upwards due to internal accumulated elastic force, it cannot bypass the top of the first insulating member 16 and overlap with the inner wall of the housing 11. This effectively reduces the risk of electrochemical corrosion caused by the tab 13 overlapping with the housing 11, thereby reducing leakage of the battery cell 10 and improving reliability.

[0156] Please refer to some embodiments of this application. Figure 10 This application provides an apparatus for preparing a battery cell. The apparatus includes a drive mechanism and a flattening wheel 20. The flattening wheel 20 is driven by the drive mechanism and rotates around its own axis. The flattening wheel 20 includes a wheel body 21 and a flattening protrusion 23. The flattening protrusion 23 is disposed on the flattening plane 22 of the wheel body 21 and extends circumferentially around the wheel body 21.

[0157] The drive mechanism refers to the component that provides power for the rotation of the flattening wheel 20. For example, the drive mechanism can be a motor; or it can be a combination of a motor and a transmission mechanism. The transmission mechanism can be, but is not limited to, a combination of gears, rollers and belts, or gears and chains.

[0158] The flattening wheel 20 is a component that applies flattening force to the end face of the tab 13; while the flattening protrusion 23 is raised on the flattening surface 22 of the wheel body 21, so that during the flattening process, the flattening protrusion 23 and the wheel body 21 respectively form flattening areas of different depths on the tab 13. In addition, the flattening protrusion 23 extends around the wheel body 21, and it can be a closed or open annular structure.

[0159] Optionally, the connection method between the flattened protrusion 23 and the wheel body 21 can be, but is not limited to, bolt connection, snap-fit, welding, bonding, or integral molding. Among them, integral molding can be, but is not limited to, extrusion, injection molding, or die casting.

[0160] The aforementioned battery cell fabrication apparatus features an annularly designed flattening protrusion 23 on the flattening surface 22 of the wheel body 21. During the flattening process, the flattening protrusion 23 preferentially acts on the tab 13. After flattening to a certain depth, the flattening surface 22 then contacts the inner ring area of ​​the tab 13 and flattens it further. Thus, using this flattening wheel 20, the tab 13 can form a first flattening portion 131 and a second flattening portion 132 with a depth difference. When the fabricated electrode assembly 12 is encapsulated within the housing 11, the second flattening portion 132, closer to the inner wall of the housing 11, is in a lower position. At this time, even if the second flattening portion 132 tilts upwards due to internal accumulated elastic force, it cannot bypass the structures surrounding the tab 13, such as the top of the first insulating member 16, and overlap with the inner wall of the housing 11. This effectively reduces the risk of electrochemical corrosion caused by the tab 13 overlapping with the housing 11, thereby reducing leakage of the battery cell 10 and improving reliability.

[0161] Please refer to some embodiments of this application. Figures 4 to 10 This application provides an electrode assembly 12. The tabs 13 of the electrode assembly 12 are flattened in a stepped manner. The flattening depth is deeper, with a width of 1mm to 5mm from the edge of the tab 13. The inner ring is flattened to a shallower depth. A first insulating member 16 is attached to the outer ring of the tab 13. This ensures that if the second flattened portion 132 of the outer ring were to lift, it would require a greater length to extend beyond the top of the first insulating member 16 and overlap with the housing 11. Because the first flattened portion 131 of the inner ring is farther from the first insulating member 16, it is less likely to overlap with the housing 11. Furthermore, the density of the second flattened portion 132 of the outer ring is higher than that of the first flattened portion 131 of the inner ring, making it less likely that the tab 13 will lift vertically.

[0162] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell (10) characterized by, Includes an electrode assembly (12), said electrode assembly (12) comprising: Main body (121); A tab (13) is provided at at least one end of the main body (121) along a predetermined direction (X) of the electrode assembly (12); The electrode ear (13) includes a first flattening portion (131) and a second flattening portion (132). The second flattening portion (132) surrounds the outer periphery of the first flattening portion (131) and is arranged along the preset direction (X). The first flattening portion (131) protrudes from the second flattening portion (132).

2. The battery cell (10) according to claim 1, characterized in that The density of the first kneaded part (131) is denoted as Q1, and the density of the second kneaded part (132) is denoted as Q2. The condition that Q1 and Q2 satisfy is: Q2 > Q1.

3. The battery cell (10) according to claim 2, characterized in that The condition that Q1 and Q2 also satisfy is: 105%≤Q2 / Q1≤140%.

4. The battery cell (10) according to claim 3, characterized in that The condition that Q1 / Q2 also satisfies is: 105%≤Q2 / Q1≤130%.

5. The battery cell (10) according to claim 1, characterized in that Along the preset direction (X), the height by which the first kneading part (131) protrudes from the second kneading part (132) is denoted as h1, where 1mm≤h1≤4mm.

6. The battery cell (10) according to claim 5, characterized in that h1 also satisfies the condition: 1mm≤h1≤2.5mm.

7. The battery cell (10) according to claim 1, characterized in that The second kneading portion (132) includes an inner edge (13a) adjacent to the first kneading portion (131) and an outer edge (13b) surrounding the inner edge (13a). The distance between the inner edge (13a) and the outer edge (13b) is denoted as L, where 1mm ≤ L ≤ 5mm.

8. The battery cell (10) according to claim 7, characterized in that L also satisfies the condition: 1mm≤L≤3mm.

9. The battery cell (10) according to claim 1, characterized in that The second kneading portion (132) includes an inner edge (13a) adjacent to the first kneading portion (131) and an outer edge (13b) surrounding the inner edge (13a). The distance between the inner edge (13a) and the outer edge (13b) is denoted as L. Along the preset direction (X), the height by which the first kneading portion (131) protrudes from the second kneading portion (132) is denoted as h1. The condition that L and h1 also satisfy is: L > h1.

10. The battery cell (10) according to any one of claims 1-9, characterized in that, The electrode assembly (12) is configured as a cylindrical structure, along a radial direction (Z) of the electrode assembly (12), an outer diameter of the electrode assembly (12) at the main body portion (121) is denoted as Y, a half of a difference between an outer diameter and an inner diameter of the second flattening portion (132) is denoted as L, and a condition between Y and L is satisfied as follows: ≤ L ≤ .

11. The battery cell (10) according to any one of claims 1 to 9, characterized in that The electrode assembly (12) includes a diaphragm (17), and the first kneading portion (131) and the second kneading portion (132) both protrude from the diaphragm (17) along the preset direction (X).

12. The battery cell (10) according to any one of claims 1 to 9, characterized in that The battery cell (10) also includes: The housing (11) has an opening (111) and houses the electrode assembly (12) therein, with the tabs (13) facing the corresponding opening (111); The first insulating member (16) is located inside the housing (11) and surrounds the outer periphery of the second flattened portion (132), and protrudes from the second flattened portion (132) along the preset direction (X).

13. The battery cell (10) according to claim 12, characterized in that Along the preset direction (X), the height of the first insulating member (16) protruding outside the second flattened part (132) is denoted as h2, where 7mm≤h2≤15mm.

14. The battery cell (10) according to claim 13, characterized in that h2 also satisfies the condition: 10mm≤h2≤15mm.

15. The battery cell (10) according to claim 12, characterized in that The first insulating member (16) protrudes from the first flattened portion (131) in the preset direction (X).

16. The battery cell (10) according to claim 12, characterized in that, The battery cell (10) also includes an end cap assembly (14) covering the opening (111), and the first insulating member (16) is in contact with the end cap assembly (14).

17. The battery cell (10) according to claim 16, characterized in that, The end cap assembly (14) includes an end cap (141) and a second insulating member (142). The end cap (141) covers the opening (111), and the second insulating member (142) is disposed on the side of the end cap (141) facing the electrode assembly (12). The first insulating member (16) surrounds at least a portion of the outer periphery of the second insulating member (142) and contacts the second insulating member (142).

18. The battery cell (10) according to claim 17, characterized in that, At least a portion of the second insulating member (142) surrounds the outer periphery of the first flattened portion (131).

19. The battery cell (10) according to claim 17, characterized in that, The first insulating member (16) is bonded to the circumferential side of the second insulating member (142).

20. The battery cell (10) according to any one of claims 17-19, characterized in that, The end cap assembly (14) includes an electrode terminal (143), and the second insulating member (142) includes a body (14a) and an extension (14b) connected to each other. The body (14a) is located between the end cap (141) and the electrode terminal (143), and the extension (14b) extends from the body (14a) toward the electrode assembly (12) and surrounds the outer periphery of the first flattened portion (131).

21. A battery (100), characterized in that, Includes the battery cell (10) as described in any one of claims 1-20.

22. An electrical appliance, characterized in that, Includes the battery (100) of claim 21, the battery (100) being used to provide electrical energy.

23. An apparatus for preparing a single battery cell, characterized in that, include: Drive mechanism; The kneading wheel (20) is driven by the drive mechanism and rotates around its own axis; The kneading wheel (20) includes a wheel body (21) and a kneading protrusion (23). The kneading protrusion (23) is disposed on the kneading plane (22) of the wheel body (21) and extends circumferentially around the wheel body (21).

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