Battery cell, battery device and electric device

Abstract

The invention discloses a single battery, a battery device and a power utilization device, and belongs to the technical field of batteries, the single battery comprises a battery cell assembly and a center pin, the battery cell assembly is provided with a center hole, the center pin is located in the center hole, the distance between the center pin and the inner wall of the center hole is D, and D is larger than or equal to 0 mm and smaller than or equal to 0.4 mm. The center needle provides a stable supporting effect on the inner wall of the center hole, and the problem of collapse of the center hole is actively prevented by introducing an internal reinforcing structure. The distance between the center needle and the inner wall of the center hole is 0-0.4 mm, and the problem that the supporting force of the center needle to the inner wall of the center hole is insufficient due to the fact that the gap between the center needle and the inner wall of the center hole is too large is solved.

Description

Technical Field

[0001] This application belongs to the field of battery technology, specifically relating to a battery cell, a battery device, and an electrical device. Background Technology

[0002] Current cylindrical lithium-ion batteries typically have a hollow structure. During battery cycling, the inner electrode plates are prone to collapse due to external pressure, internal stress, or expansion forces generated by electrochemical reactions. This collapse affects the structural stability of the cell and poses risks such as electrode short circuits, capacity reduction, and lifespan degradation. Summary of the Invention

[0003] This application aims to provide a battery cell, a battery device, and an electrical device that at least solves the problem in the related art where the collapse of the inner electrode of the battery affects the structural stability of the cell and leads to risks such as electrode short circuits, capacity and lifespan degradation.

[0004] To solve the above-mentioned technical problems, this application is implemented as follows:

[0005] In a first aspect, embodiments of this application propose a battery cell, which includes a cell assembly and a center pin. The cell assembly has a center hole, and the center pin is located inside the center hole. The distance between the center pin and the inner wall of the center hole is D, where 0 mm ≤ D ≤ 0.4 mm.

[0006] The battery cell assembly has a central hole into which a central pin is inserted, providing support to the inner wall of the hole. In this assembly, the cell, composed of wound electrodes and a separator, lacks internal support at the central hole location. When the battery is operating, especially during charging, lithium ions embed into the negative electrode material, causing significant expansion of the negative electrode particles. This expansion generates substantial internal stress, compressing the entire wound core structure from the inside out. The central pin provides stable support to the inner wall of the central hole, actively preventing its collapse by introducing an internal reinforcement structure.

[0007] After assembling the center pin and center hole, at least a portion of the center pin's surface is in contact with the inner wall of the center hole. A gap may also exist between the center pin's surface and the inner wall of the center hole. To ensure stable support of the center pin against the inner wall of the center hole, the distance between the center pin and the inner wall needs to be limited. The distance between the center pin and the inner wall of the center hole is between 0 mm and 0.4 mm; that is, the maximum distance between the center pin and the inner wall of the center hole cannot exceed 0.4 mm. This avoids insufficient support from the center pin against the inner wall of the center hole due to excessive gaps. Therefore, within this range, the center pin can stably support the inner wall of the center hole, preventing the center hole from collapsing.

[0008] In one possible embodiment, the static friction force applied to the central needle by the inner wall of the central hole is f, and the weight of the central needle is m, where f > m.

[0009] By defining the relationship between the frictional force on the center pin and its own weight, a reliable positioning solution for the center pin without the need for additional fasteners is provided. This simplifies the structural design and assembly process, improves the positional stability of the center pin throughout its entire life cycle, and avoids risks such as short circuits and support failures that may be caused by component displacement, thereby enhancing the reliability and safety of the product.

[0010] In one possible embodiment, 1×m<f≤30×m.

[0011] When the gravity and friction of the center pin meet the above-mentioned range, and the center pin is stably fixed, the problem of local stress concentration caused by the excessive tight fit between the center pin and the center hole is avoided, which is conducive to improving the service life of the battery cell.

[0012] In one possible embodiment, the center pin supports the coating area in the cell assembly, with both ends of the center pin protruding from the coating area along the axial direction of the cell assembly.

[0013] The tip of the central needle does not contact the edge of the coating area, reducing the likelihood of stress concentration at the edge and minimizing the risk of edge damage. This provides a more ample safety boundary for potential abnormal expansion or external impacts, further enhancing the protective function of the coating area.

[0014] The length of the center needle is L1, and the length of the coating area is L2, where L1 ≥ L2.

[0015] Since the coating area is the primary region where electrochemical expansion occurs and is the core part most in need of support, this design allows the central pin to effectively support this critical area, preventing support blind spots in the coating area due to insufficient support length and avoiding stress concentration problems. This effectively prevents structural damage to the inner electrode sheets caused by insufficient local support, improving the structural stability of the battery cell during cycling.

[0016] In one possible embodiment, the battery cell assembly includes a tab portion and a flattened portion. Along the axial direction of the battery cell assembly, the coating area and the flattened portion are located on both sides of the tab portion. Along the axial direction of the battery cell assembly, the end of the center pin does not protrude from the side of the flattened portion away from the tab portion.

[0017] The center needle does not extend beyond the bending area of ​​the tab, that is, the center needle does not extend beyond the kneading section, to prevent the center needle from affecting the function of the kneading section.

[0018] In one possible embodiment, along the axial direction of the cell assembly, one end of the center pin protrudes from the coating area by a length of L4, and the other end of the center pin protrudes from the coating area by a length of L5, where 0mm≤L4≤10mm and 0mm≤L5≤10mm.

[0019] When L4 and L5 meet the above-mentioned requirements, the effectiveness of the center pin in supporting the edge of the coating area is improved, avoiding the risk of interference with other structures that may be caused by an excessively long center pin. Effective support of the coating area improves compatibility with the battery cell and manufacturing feasibility.

[0020] In one possible embodiment, the battery cell assembly includes electrode sheets, which are wound in a multi-layer structure. Among the multi-layer electrode sheets, N layers of electrode sheets adjacent to the center pin are provided with recessed portions, which are bent toward the center pin, and N≤5.

[0021] Even if the distance between the inner wall of the center hole and the center pin is small, some electrode sheets will still be dented. However, since the distance between the center pin and the inner wall of the center hole is less than or equal to 0.4 mm, even if the electrode sheets are dented, only a small number of inner electrode sheets will be dented, which greatly reduces the impact on the core structure.

[0022] In one possible embodiment, the battery cell assembly includes bare cells with a length of L3 along the axial direction of the battery cell assembly, where L1 < L3.

[0023] Because the length of the center pin is shorter than the length of the bare cell, interference with the tab processing can be avoided. When the lengths of the center pin and the bare cell meet the above conditions, the yield rate of battery cell manufacturing and the reliability of the final product are improved, and the probability of internal short circuits caused by an excessively long center pin is reduced.

[0024] In one possible embodiment, the coaxiality of the center pin and the center hole is 0, where 0 mm ≤ 0 ≤ 0.4 mm.

[0025] The core purpose of controlling the coaxiality O within 0.4mm is to minimize the uneven support of the center pin in the circumferential direction. This ensures that the center pin provides a uniform and stable 360-degree support force to the center hole, avoiding uneven distribution of support force or uneven stress on the center hole caused by the misalignment of the center pin and the center hole.

[0026] In one possible embodiment, the center pin is an elastic center pin.

[0027] The center pin has a certain degree of elasticity or adjustability, and can adapt to the gap changes caused by the expansion or contraction of the inner electrode plates in the battery cell assembly during charging and discharging, thus maintaining a stable support effect.

[0028] Secondly, embodiments of this application provide a battery device, which includes the battery cell described in the first aspect.

[0029] Thirdly, embodiments of this application provide an electrical device, which includes the battery device described in the second aspect.

[0030] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0031] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0032] Figure 1 This is one of the structural schematic diagrams of a battery cell according to an embodiment of the present invention;

[0033] Figure 2 This is a second schematic diagram of the structure of a battery cell according to an embodiment of the present invention;

[0034] Figure 3 This is the third schematic diagram of the structure of a battery cell according to an embodiment of the present invention;

[0035] Figure 4 This is the fourth schematic diagram of the structure of a battery cell according to an embodiment of the present invention;

[0036] Figure 5 This is a schematic diagram of the structure of the electrode sheet according to an embodiment of the present invention;

[0037] Figure 6 This is a schematic diagram showing the dimensional relationship between the center needle and the coating area according to an embodiment of the present invention;

[0038] Figure 7 This is a partial schematic diagram of a battery cell according to an embodiment of the present invention;

[0039] Figure 8 This is a schematic diagram of the structure of a battery device according to an embodiment of the present invention;

[0040] Figure 9 This is a schematic diagram of the structure of an electrical device according to an embodiment of the present invention.

[0041] Figure label:

[0042] 100 Battery cell, 110 Cell assembly, 111 Center hole, 112 Recess, 113 Coated area, 114 Bare cell, 115 First tab, 116 Second tab, 117 Tab part, 118 Flattened part, 119 Electrode, 120 Center pin, 200 Electrical device, 300 Battery assembly, 310 Housing. Detailed Implementation

[0043] Embodiments of the present invention will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0044] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0045] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0046] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0047] The following is combined Figures 1-9 A battery cell, a battery device, and an electrical device are described according to embodiments of the present invention.

[0048] In battery production, the winding of battery cell components is a crucial step. A typical battery cell assembly consists of an anode sheet, a separator, a cathode sheet, and another separator, all wound together using a winding machine. For cylindrical batteries, which offer advantages such as high density, high safety, and long lifespan, the cyclic expansion force of the cell is significant. The central hole within the inner ring of the cylindrical cell is at risk of collapse, necessitating the installation of a central pin for support within the cell's inner hole.

[0049] In related technologies, battery cell components are typically hollow structures. During battery cycling, the inner electrode plates are prone to collapse due to external pressure, internal stress, or expansion forces generated by electrochemical reactions. This collapse affects the structural stability of the battery cell component and also poses problems and risks such as electrode short circuits, capacity and lifespan degradation, seriously impacting battery performance, lifespan, and consumer safety.

[0050] Based on the above considerations, a center pin is inserted into the center hole. The center pin supports the inner wall of the center hole, and the inner wall of the center hole provides stable support. By introducing an internal reinforcing structure, the collapse of the center hole is actively prevented. Furthermore, the maximum distance between the center pin and the inner wall of the center hole is limited to no more than 0.4 mm to avoid insufficient support force from the center pin on the inner wall of the center hole due to excessive gaps between them.

[0051] It is understood that the electrical devices applicable to the use of battery cells described in the embodiments of this application can take many forms, such as mobile phones, portable devices, laptops, electric vehicles, electric cars, ships, spacecraft, electric toys, and power tools, etc. For example, spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers.

[0052] like Figure 9 As shown, the battery cell 100 described in the embodiments of this application is not only applicable to the electrical device 200 described above, but also applicable to all electrical devices 200 that use the battery cell 100.

[0053] like Figure 8 As shown, in an embodiment of this application, a battery device 300 is proposed. The battery device 300 includes a battery cell 100 and a housing 310 as described in the above embodiment, with a plurality of battery cells 100 located inside the housing 310.

[0054] In some embodiments of this application, the battery device 300 can be used to power a vehicle; for example, the battery device 300 can serve as the vehicle's operating power source. A controller is used to control the battery device 300 to supply power to the motor, for example, to meet the vehicle's power needs during starting, navigation, and driving.

[0055] In other embodiments, the battery device 300 can not only serve as the operating power source for the vehicle, but also as the driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

[0056] In this application, the battery device 300 mentioned in the embodiments refers to a single physical module comprising one or more battery cells 100 to provide higher voltage and capacity. For example, the battery device 300 is composed of multiple battery cells 100 connected in series or in parallel.

[0057] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, in some embodiments of this application, a battery cell 100 is proposed. The battery cell 100 includes a cell assembly 110 and a center pin 120. The cell assembly 110 has a center hole 111. The center pin 120 is located inside the center hole 111. The distance between the center pin 120 and the inner wall of the center hole 111 is D, where 0 mm ≤ D ≤ 0.4 mm.

[0058] The battery cell assembly 110 has a central hole 111, into which a central pin 120 is inserted, providing support to the inner wall of the central hole 111. In the battery cell assembly 110, which is formed by winding electrode sheets and a separator, there is a lack of internal support at the central hole 111. When the battery is working, especially during charging, lithium ions embed into the negative electrode material, causing significant expansion of the negative electrode particles. This expansion generates enormous internal stress, squeezing the entire wound core structure from the inside out. The central pin 120 provides stable support to the inner wall of the central hole 111, actively preventing the collapse of the central hole 111 by introducing an internal reinforcement structure.

[0059] After assembling the center pin 120 and the center hole 111, at least a portion of the surface of the center pin 120 is in contact with the inner wall of the center hole 111. A gap may also exist between a portion of the surface of the center pin 120 and the inner wall of the center hole 111. To ensure stable support of the center pin 120 for the inner wall of the center hole 111, the distance between the center pin 120 and the inner wall of the center hole 111 needs to be limited. The distance between the center pin 120 and the inner wall of the center hole 111 is between 0 mm and 0.4 mm; that is, the maximum distance between the center pin 120 and the inner wall of the center hole 111 cannot exceed 0.4 mm. This avoids the problem of insufficient support force from the center pin 120 for the inner wall of the center hole 111 due to an excessively large gap. Therefore, within the above range, the center pin 120 can stably support the inner wall of the center hole 111, reducing the probability of the center hole 111 collapsing.

[0060] The average gap between the center pin 120 and the center hole 111 is 0 mm to 0.4 mm. The inner wall of the center hole 111 and the center pin 120 maintain a suitable gap of 0 mm to 0.4 mm so that the center pin 120 can provide a certain support force and avoid the center pin 120 from supporting the inner circle electrode due to excessive gap, thereby causing collapse.

[0061] It should be noted that before the center pin 120 is assembled into the center hole 111, the difference between the radius of the center pin 120 and the radius of the center hole 111 may be within the range of 0mm to 0.4mm, or it may be outside the range of 0mm to 0.4mm. This is because during the assembly of the center pin 120, it is necessary to consider whether the center pin 120 will scratch the inner wall of the center hole 111. Therefore, it may be necessary to adjust the radial dimensions of the center pin 120 or the center hole 111. For example, a center pin 120 with a smaller radius can be inserted into the center hole 111 (at this time, the difference between the radius of the center pin 120 and the radius of the center hole 111 is relatively large to avoid the center pin 120 scratching the inner wall of the center hole 111). Then, a support member is used to support the hollow center pin 120. The radial dimension of the support member can be varied. By increasing the radial dimension of the support member, the radial dimension of the center pin 120 is enlarged, thereby making the center pin 120 as close as possible to the inner wall of the center hole 111. After the center pin 120 and center hole 111 are assembled, the distance between the center pin 120 and the inner wall of the center hole 111 is in the range of 0 mm to 0.4 mm.

[0062] The gap distance range is determined based on the thickness, rebound, material properties, and expansion and contraction characteristics of the inner ring electrode of the battery cell. During the manufacturing process, a corresponding small gap center pin process and high-precision processing equipment are used to ensure processing accuracy, thereby achieving precise control of the gap distance.

[0063] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, in one possible embodiment, the static friction force applied to the center needle 120 by the inner wall of the center hole 111 is f, and the weight of the center needle 120 is m, where f > m.

[0064] The inner walls of the center pin 120 and the center hole 111 will come into contact and be squeezed locally. The static friction force on the center pin 120 is used to overcome gravity. When the battery cell 100 adjusts its posture or experiences vibration and impact, the center pin 120 is not likely to move axially or fall off in the center hole 111.

[0065] By limiting the relationship between the frictional force on the center pin 120 and its own weight, a reliable positioning solution for the center pin 120 without the need for additional fasteners is provided. This simplifies the structural design and assembly process, improves the positional stability of the center pin 120 throughout its entire life cycle, and reduces the risks of short circuits and support failures that may be caused by component displacement, thereby enhancing the reliability and safety of the product.

[0066] In one possible embodiment, 1×m<f≤30×m.

[0067] The numerical range in this embodiment is set based on a comprehensive analysis of the inertial force and the coefficient of friction of the material under actual working conditions. The lower limit of the frictional force on the center pin 120 is 1 times the weight of the center pin 120, thus providing a safety margin for the center pin 120 to cope with dynamic working conditions. The upper limit of the frictional force on the center pin 120 is 30 times the weight of the center pin 120, which prevents assembly difficulties or constraints on the normal expansion of the electrode due to excessive frictional force on the center pin 120.

[0068] When the gravity and friction of the center pin 120 meet the above-mentioned range, and under the premise of stable fixation of the center pin 120, the problem of local stress concentration caused by excessive tight fit between the center pin 120 and the center hole 111 is avoided, which is conducive to improving the service life of the battery cell 100.

[0069] Combination Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, in one possible embodiment, the center pin 120 supports the coating area 113 in the cell assembly 110 along the axial direction of the cell assembly 110. Figure 1 (The arrow at H in the middle points to) The two ends of the central needle 120 protrude from the coating area 113 respectively.

[0070] Both ends of the center pin 120 extend axially beyond the coating area 113. The ends of the center pin 120 do not contact the edge area of ​​the coating area 113, thus reducing the risk of stress concentration at the edge of the coating area 113 and minimizing the risk of damage to the edge of the coating area 113. This provides a more ample safety boundary for possible abnormal expansion or external impacts, further enhancing the protective function of the coating area 113.

[0071] The length of the center needle 120 is L1, and the length of the coating area 113 is L2, where L1 ≥ L2.

[0072] In this embodiment, the axial length L1 of the center pin 120 is limited to be no less than the length L2 of the coating area 113. Since the coating area 113 is the main region where electrochemical expansion occurs and is also the core part that most needs support, this design allows the center pin 120 to effectively support this critical area, avoiding support blind spots in the coating area 113 due to insufficient support length, and reducing the likelihood of stress concentration. This effectively reduces the probability of structural damage to the inner electrode sheet due to insufficient local support and improves the structural stability of the battery cell 100 during cycling.

[0073] In one possible embodiment, the battery cell assembly 110 includes a tab portion 117 and a flattening portion 118. Along the axial direction of the battery cell assembly 110, the coating area 113 and the flattening portion 118 are located on both sides of the tab portion 117. Along the axial direction of the battery cell assembly 110, the end of the center pin 120 does not protrude from the flattening portion 118 on the side opposite to the tab portion 117.

[0074] The center needle 120 does not extend beyond the bending area of ​​the ear portion 117, that is, the center needle 120 does not extend beyond the kneading portion 118, and the center needle is unlikely to affect the function of the kneading portion 118.

[0075] The electrode portion 117 includes a first electrode 115 and a second electrode 116.

[0076] Combination Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 As shown, in one possible embodiment, along the axial direction of the cell assembly 110, one end of the center pin 120 protrudes from the coating area 113 by a length of L4, and the other end of the center pin 120 protrudes from the coating area 113 by a length of L5, where 0mm≤L4≤10mm and 0mm≤L5≤10mm.

[0077] The length of the two ends of the center pin 120 protruding from the coating area 113 is controlled between 0 mm and 10 mm. While the center pin 120 provides support for the coating area 113, the length of the center pin 120 protruding from the coating area 113 is limited to prevent the center pin 120 from extending too far and interfering with other key structures at the top and bottom of the bare cell 114.

[0078] When L4 and L5 meet the above-mentioned requirements, the effectiveness of the center pin 120 in supporting the edge of the coating area 113 is improved, avoiding the risk of interference with other structures that may be caused by the excessive length of the center pin 120. Effective support for the coating area 113 improves compatibility with the battery cell 100 and enhances manufacturing feasibility.

[0079] like Figure 7 As shown, in one possible embodiment, the battery cell assembly 110 includes electrode sheets 119. The wound electrode sheets 119 have a multi-layer structure. Among the multi-layer electrode sheets 119, the N-layer electrode sheets 119 adjacent to the center pin 120 are provided with recessed portions 112. The recessed portions 112 are bent toward the center pin 120, and N≤5.

[0080] Even if the distance between the inner wall of the center hole 111 and the center pin 120 is small, some electrode sheets 119 will be dented. However, since the distance between the center pin 120 and the inner wall of the center hole 111 is less than or equal to 0.4 mm, even if the electrode sheets 119 are dented, only a small number of inner electrode sheets 119 will be dented, which greatly reduces the impact on the core structure.

[0081] Combination Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, in one possible embodiment, the battery cell assembly 110 includes a bare battery cell 114, and the length of the bare battery cell 114 along the axial direction of the battery cell assembly 110 is L3, where L1 < L3.

[0082] In this embodiment, the length of the center pin 120 is limited to be less than the total length of the bare cell 114. Within this range, the center pin 120 is completely contained within the internal space of the bare cell 114. This prevents the center pin 120 from pressing against the casing of the battery cell 100. Furthermore, during the manufacturing of the battery cell 100, after the bare cell 114 is assembled into the casing, the top and bottom tabs of the bare cell 114 need to be flattened to make the tabs smooth. Since the length of the center pin 120 is less than the length of the bare cell 114, the center pin 120 can avoid interfering with the tab processing. When the lengths of the center pin 120 and the bare cell 114 meet the above conditions, the yield rate of the battery cell 100 manufacturing and the reliability of the final product are improved, and the probability of internal short circuits caused by an excessively long center pin 120 is reduced.

[0083] The above embodiments are met to ensure that the length of the center pin 120 is appropriate and that the center pin 120 is centered in the height direction relative to the bare cell 114. There will be no stress concentration problem at the end face of the center pin 120 caused by the center pin 120 being too short or offset, and the center pin 120 entering the flattening layer will affect the welding and flattening.

[0084] In one possible embodiment, the coaxiality of the center pin 120 and the center hole 111 is 0, where 0 mm ≤ 0 ≤ 0.4 mm.

[0085] The coaxiality error between the axis of the center pin 120 and the axis of the center hole 111 is limited to the range of 0 mm to 0.4 mm. Coaxiality is a core indicator for measuring the alignment accuracy of two cylindrical feature axes in space. Controlling the coaxiality 0 to within 0.4 mm aims to minimize the uneven support of the center pin 120 in the circumferential direction. This ensures that the center pin 120 provides a uniform and stable 360-degree support force to the center hole 111, avoiding uneven distribution of support force or uneven stress on the center hole 111 caused by the misalignment of the center pin 120 and the center hole 111.

[0086] In one possible embodiment, the center pin 120 is an elastic center pin.

[0087] The center pin 120 has a certain degree of elasticity or adjustability. The center pin 120 can adapt to the gap changes caused by the expansion or contraction of the inner ring electrode in the battery cell assembly 110 during charging and discharging, and maintain a stable support effect.

[0088] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0089] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A battery cell, characterized by, include: Battery cell assembly, the battery cell assembly having a central hole; A center pin is located inside the center hole, and the distance between the center pin and the inner wall of the center hole is D, where 0mm≤D≤0.4mm.

2. The battery cell of claim 1, wherein, The static friction force applied to the central needle by the inner wall of the central hole is f, and the weight of the central needle is m, where f > m.

3. The battery cell according to claim 2, characterized in that, 1×m<f≤30×m.

4. The battery cell according to claim 1, characterized in that, The center pin supports the coating area in the battery cell assembly, and both ends of the center pin protrude from the coating area along the axial direction of the battery cell assembly.

5. The battery cell according to claim 4, characterized in that, The battery cell assembly includes a tab portion and a flattened portion. Along the axial direction of the battery cell assembly, the coating area and the flattened portion are located on both sides of the tab portion, and the end of the center needle does not protrude from the side of the flattened portion away from the tab portion.

6. The battery cell according to claim 4, characterized in that, Along the axial direction of the battery cell assembly, one end of the center needle protrudes from the coating area by a length of L4, and the other end of the center needle protrudes from the coating area by a length of L5, where 0mm≤L4≤10mm and 0mm≤L5≤10mm.

7. The battery cell according to any one of claims 1 to 6, characterized in that, The battery cell assembly includes electrode sheets, and the wound electrode sheets have a multi-layer structure. Among the multi-layer electrode sheets, the N layers of electrode sheets adjacent to the center pin are provided with recessed portions, and the recessed portions are bent toward the center pin, where N≤5.

8. The battery cell according to any one of claims 1 to 6, characterized in that, The battery cell assembly includes bare battery cells. Along the axial direction of the battery cell assembly, the length of the center pin is L1, and the length of the bare battery cell is L3, where L1 < L3.

9. The battery cell according to any one of claims 1 to 6, characterized in that, The coaxiality of the center pin and the center hole is 0, where 0mm ≤ 0 ≤ 0.4mm.

10. The battery cell according to any one of claims 1 to 6, characterized in that, The center needle is an elastic center needle.

11. A battery device, characterized in that, include: The battery cell as described in any one of claims 1 to 10.

12. An electrical appliance, characterized in that, include: The battery device as claimed in claim 11.

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