A battery cell, a battery and an electric device

Abstract

This application discloses a battery cell, a battery, and an electrical device, belonging to the field of battery technology. The battery cell includes a casing and a core. The casing includes a bottom shell and a cover assembly. One end of the bottom shell is closed, and the other end is open, forming an opening. The core, composed of a positive electrode sheet, a separator, and a negative electrode sheet, is placed inside the bottom shell through this opening. The cover assembly seals the opening. The minimum distance from the inner surface of the bottom wall of the bottom shell to the inner surface of the cover assembly is H1. The width of the negative electrode sheet of the core is W1, where 0.8 ≤ W1 / H1 ≤ 0.9. This allows for a 10% to 20% buffer space to be reserved within the casing for the negative electrode sheet. When the battery cell is subjected to planar compression, this can delay internal pressure, reduce the rate of heat accumulation, and help reduce the risk of fire and explosion, thus improving the safety of the battery cell. This battery and electrical device can prevent battery fires or explosions when subjected to planar compression, exhibiting good safety.

Description

Technical Field

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

[0002] For high-energy-density battery cells, high-capacity cathode materials, such as ternary materials, are often required. However, ternary materials have poor safety performance. In particular, when the battery cell is subjected to external mechanical abuse (such as planar extrusion), it can cause internal short circuits in the battery cell, generating large currents and causing heat accumulation. Ternary materials have poor thermal stability, which can easily cause the battery cell to catch fire or explode, posing a significant safety hazard.

[0003] This section is intended to provide background or context for embodiments of this application. The description herein is not intended to imply that it is prior art. Utility Model Content

[0004] The purpose of this application is to solve or at least mitigate some or all of the aforementioned problems. Therefore, the purpose of this application is to provide a battery cell, a battery, and an electrical device, wherein the battery cell has high energy density and high safety performance, and can prevent battery fire or explosion when subjected to planar compression, thus exhibiting good safety.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] In a first aspect, this application provides a battery cell, comprising:

[0007] The outer casing includes a bottom shell and a cover plate assembly. One end of the bottom shell is closed and the other end is open to form an opening. The cover plate assembly is sealed and covered at the opening. The minimum distance from the inner surface of the bottom wall of the bottom shell to the inner surface of the cover plate assembly is H1.

[0008] The core is formed by winding a positive electrode sheet, a separator, and a negative electrode sheet. The width of the negative electrode sheet is W1, and the ratio between W1 and H1 is in the range of 0.8 ≤ W1 / H1 ≤ 0.9.

[0009] As an optional embodiment of the battery cell, the width W1 of the negative electrode sheet is greater than the width W2 of the positive electrode sheet of the core and less than the width W3 of the separator of the core. The height of the core is H2, and the ratio between H2 and H1 is in the range of 0.9 ≤ H2 / H1 ≤ 0.95.

[0010] As an optional embodiment of the battery cell, before the core is formed, the difference between the width W3 of the separator and the width W1 of the negative electrode sheet is within the range of: 1mm ≤ W3 - W1 ≤ 2mm; and / or

[0011] The difference between the width W1 of the negative electrode and the width W2 of the positive electrode is in the range of 0.2mm ≤ W1 - W2 ≤ 0.6mm.

[0012] As an optional embodiment of the battery cell, the inner diameter of the bottom shell is D1, the diameter of the core is D2, and the ratio between D2 and D1 is in the range of 0.95≤D2 / D1≤0.99.

[0013] As an optional embodiment of the battery cell, the core has a separator pre-wound section, which is formed by winding the separator. The diameter of the separator pre-wound section is D4, and the ratio between D4 and D1 is in the range of 0.15≤D4 / D1≤0.2.

[0014] As an optional embodiment of the battery cell, the diameter of the winding needle for winding the positive electrode, the separator, and the negative electrode is D3, and the ratio between D3 and D1 is in the range of 0.1≤D3 / D1≤0.15.

[0015] As an optional embodiment of the battery cell, both the negative tab and the positive tab of the winding core are located at one end of the winding core near the cover plate assembly.

[0016] As an optional embodiment of the battery cell, the cover plate assembly includes a cover plate and a terminal post. The cover plate has a through hole, the terminal post passes through the through hole and forms an upper terminal post on the outside of the cover plate, and forms a lower terminal post on the inside of the cover plate. The free end of the positive terminal tab is fixedly connected to the lower terminal post, and the free end of the negative terminal tab is fixedly connected to the cover plate and the bottom shell.

[0017] As an optional embodiment of the battery cell, the diameter of the upper electrode post is D5, and the ratio between D5 and D1 is in the range of: 0.2 ≤ D5 / D1 ≤ 0.5; and / or

[0018] The diameter of the lower pole post is D6, and the ratio between D6 and D1 is in the range of 0.6 ≤ D6 / D1 ≤ 0.9.

[0019] As an alternative to the aforementioned battery cell, D1 > H1; or

[0020] D1 < H1.

[0021] Secondly, this application provides a battery comprising a single battery cell as described in any of the preceding claims.

[0022] Thirdly, this application provides an electrical device including the battery described above.

[0023] The beneficial effects of this application are as follows:

[0024] The battery cell provided in this application includes a casing and a core. The casing includes a bottom shell and a cover assembly. One end of the bottom shell is closed, and the other end is open to form an opening. The core, which is made of a positive electrode sheet, a separator, and a negative electrode sheet, is placed inside the bottom shell through the opening. The cover assembly is used to seal the opening. The minimum distance from the inner surface of the bottom wall of the bottom shell to the inner surface of the cover assembly is H1. The width of the negative electrode sheet of the core is W1. The ratio between W1 and H1 is in the range of 0.8≤W1 / H1≤0.9, so as to reserve a buffer space of 10% to 20% for the negative electrode sheet inside the casing. When the battery cell is subjected to planar compression, it can delay the internal pressure, reduce the heat accumulation rate, and help reduce the risk of fire and explosion, thereby improving the safety of the battery cell.

[0025] The battery and power device provided in this application, by using the aforementioned battery cells, can avoid battery fires or explosions when subjected to flat surface compression, thus exhibiting good safety. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the content of the embodiments of this application and these drawings without creative effort.

[0027] Figure 1 This is a cross-sectional schematic diagram of a battery cell provided in an embodiment of this application.

[0028] Figure 2 This is a front view of the core before it is installed in the housing, as provided in the embodiments of this application.

[0029] Figure 3 This is a top view of the core before it is installed in the housing, as provided in the embodiments of this application.

[0030] Figure 4 This is a schematic diagram of the positive electrode sheet, separator, and negative electrode sheet laid flat before winding, as provided in the embodiments of this application.

[0031] Figure 5 This is a schematic diagram showing the relationship between the inner diameter D1 of the bottom shell, the diameter D2 of the core, the diameter D3 of the winding needle, and the diameter D4 of the diaphragm pre-winding section provided in the embodiments of this application.

[0032] Figure label:

[0033] 100. Outer shell; 200. Core; 201. Diaphragm pre-winding section; 202. Positive electrode tab; 203. Negative electrode tab; 300. Winding needle;

[0034] 1. Bottom shell;

[0035] 21. Cover plate; 22. Terminal post; 221. Upper terminal post; 222. Lower terminal post; 23. Insulating component;

[0036] 3. Positive electrode plate;

[0037] 4. Diaphragm;

[0038] 5. Negative electrode plate. Detailed Implementation

[0039] Before explaining any implementation of this application in detail, it should be understood that this application is not limited to its application to the structural details and component arrangements set forth in the following description or shown in the above drawings.

[0040] In this application, the terms "comprising," "including," "having," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0041] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this application generally indicates that the preceding and following related objects have an "and / or" relationship.

[0042] In this application, the terms "connection," "combination," "coupling," and "installation" can refer to direct connection, combination, coupling, or installation, or indirect connection, combination, coupling, or installation. For example, a direct connection refers to two parts or components being connected together without the need for an intermediary, while an indirect connection refers to two parts or components each being connected to at least one intermediary, with the connection achieved through the intermediary. Furthermore, "connection" and "coupling" are not limited to physical or mechanical connections or couplings, but can also include electrical connections or couplings.

[0043] In this application, those skilled in the art will understand that relative terms (e.g., “about,” “approximately,” “basically,” etc.) used in conjunction with quantities or conditions are to include the values ​​and have the meaning indicated by the context. For example, such relative terms include at least the degree of error associated with the measurement of a particular value, tolerances associated with the particular value due to manufacturing, assembly, use, etc. Such terms should also be considered as disclosing a range defined by the absolute values ​​of the two endpoints. Relative terms may refer to a certain percentage (e.g., 1%, 5%, 10% or more) of the indicated value. Numerical values ​​not using relative terms should also be disclosed as specific values ​​with tolerances. Furthermore, “basically” when expressing relative angular relationships (e.g., substantially parallel, substantially perpendicular) may refer to a certain degree (e.g., 1 degree, 5 degrees, 10 degrees or more) added to or subtracted from the indicated angle.

[0044] In this application, those skilled in the art will understand that the function performed by a component can be performed by one component, multiple components, one part, or multiple parts. Similarly, the function performed by a part can also be performed by one part, one component, or a combination of multiple parts.

[0045] In this application, the directional terms "upper," "lower," "left," "right," "front," and "rear" are used to describe the orientation and positional relationships shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should be understood that when an element is mentioned as being connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected through an intermediate element. It should also be understood that directional terms such as upper side, lower side, left side, right side, front side, and rear side not only represent positive orientation but can also be understood as lateral orientation. For example, "below" can include directly below, lower left, lower right, lower front, and lower rear.

[0046] This application provides a battery cell, a battery using the battery cell, and an electrical device using the battery. The battery cell may be a lithium-ion battery, and a battery refers to a single physical module comprising one or more battery cells to provide higher voltage and capacity, such as a battery module or battery pack. The electrical device refers to a device that uses a battery as its power source, such as devices in the fields of 3C electronic products, electric toys, power tools, energy storage systems, electric vehicles, and aerospace.

[0047] It should be noted that the technical solutions for individual battery cells described below are applicable to batteries that use these individual battery cells and electrical devices that use these batteries, and will not be elaborated upon further.

[0048] In related technologies, when a battery cell is subjected to external mechanical abuse (such as planar extrusion), it can cause a short circuit inside the battery cell, generating a large current and causing heat to accumulate. Ternary materials have poor thermal stability, which can easily cause the battery cell to catch fire or explode, posing a significant safety hazard.

[0049] To improve the safety of battery cells when subjected to external mechanical abuse, this application provides a battery cell, such as... Figures 1 to 5 As shown, the battery cell includes a housing 100 and a core 200. The housing 100 includes a bottom shell 1 and a cover assembly. One end of the bottom shell 1 is closed, and the other end is open to form an opening. The core 200, which is formed by winding a positive electrode 3, a separator 4, and a negative electrode 5, is placed inside the bottom shell 1 through the opening. The cover assembly is sealed at the opening. The minimum distance from the inner surface of the bottom wall of the bottom shell 1 to the inner surface of the cover assembly is H1 (hereinafter referred to as the effective space height H1 inside the housing 100). The width of the negative electrode 5 of the core 200 is W1. The ratio between W1 and H1 is in the range of 0.8≤W1 / H1≤0.9, so as to reserve a buffer space of 10% to 20% for the negative electrode 5 inside the housing 100. When the battery cell is subjected to planar compression, it can delay the internal pressure, reduce the heat accumulation rate, and help reduce the risk of fire and explosion, thereby improving the safety of the battery cell.

[0050] In one embodiment, the ratio between W1 and H1 can be 0.8, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, or 0.90, and will not be listed here. The ratio between the width W1 of the negative electrode 5 of the core 200 and the effective space height H1 inside the outer casing 100 refers to the ratio of the negative electrode 5 of the core 200 to the effective space inside the outer casing 100 in the height direction after the core 200 is placed inside the outer casing 100. The larger the ratio, the smaller the distance between the negative electrode 5 of the core 200 and the inner surface of the outer casing 100 in the height direction (which can be the inner surface of the bottom wall of the bottom shell 1 or the inner surface of the cover assembly). The more easily the negative electrode 5 contacts the inner surface of the outer casing 100 in the height direction, the lower the safety. The smaller the ratio, the larger the distance between the negative electrode 5 of the core 200 and the inner surface of the outer casing 100 in the height direction (which can be the inner surface of the bottom wall of the bottom shell 1 or the inner surface of the cover assembly). The less easily the negative electrode 5 contacts the inner surface of the outer casing 100 in the height direction, the higher the safety.

[0051] In one embodiment, the inner diameter of the bottom shell 1 is D1, where D1 > H1. In this case, the battery cell is a button cell. In another embodiment, the inner diameter of the bottom shell 1 is D1 < H1. In this case, the battery cell is a cylindrical cell. In other words, the battery cell provided in this application can be either a button cell or a cylindrical cell, and the technical solution for this battery cell is applicable to both button cells and cylindrical cells.

[0052] The width of the negative electrode 5 is greater than the width of the positive electrode 3 of the core 200, but less than the width of the separator 4 of the core 200. The height of the core 200 formed by winding the positive electrode 3, separator 4, and negative electrode 5 is H2. The ratio between H2 and H1 is in the range of 0.9 ≤ H2 / H1 ≤ 0.95, so that the core 200 reserves a buffer space of 5% to 10% within the outer casing 100, which can improve the safety of the battery cell and ensure the energy density of the battery cell. In other words, the height H2 of the core 200 is determined by the width of the separator 4. When the battery cell is squeezed by an external plane, the separator 4 of the core 200 is stressed first, followed by the negative electrode 5 and positive electrode 3, which can also improve the safety of the battery cell to a certain extent.

[0053] In one embodiment, the ratio between H2 and H1 can be 0.9, 0.91, 0.92, 0.93, 0.94, 0.95, etc., and will not be listed here.

[0054] When the positive electrode 3, separator 4, and negative electrode 5 are wound to form a coil, the two end faces of the coil need to be flattened to finally form the core 200. Therefore, the actual height H2 of the core 200 will be less than the width W3 of the separator 4 before winding. Before the core 200 is formed, the difference between the width W3 of the separator 4 and the width W1 of the negative electrode 5 is: 1mm ≤ W3 - W1 ≤ 2mm. In one embodiment, the difference between W3 and W1 can be 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, 2mm, etc., which will not be listed here.

[0055] The larger the difference between the width W3 of the separator 4 and the width W1 of the negative electrode 5, the larger the width W3 of the separator 4. While this improves the short-circuit protection effect of the separator 4, it also increases the material cost of the separator 4 and the height H2 of the core 200, thus reducing the space reserved for the core 200 within the effective space of the outer casing 100. Conversely, the smaller the difference between the width W3 of the separator 4 and the width W1 of the negative electrode 5, the smaller the width W3 of the separator 4. In this case, the short-circuit protection effect of the separator 4 is relatively reduced, but the space reserved for the core 200 within the effective space of the outer casing 100 is increased, and the resistance to external planar compression is improved.

[0056] To prevent lithium plating, avoid short circuits, and improve the tolerance of the manufacturing process, the width W2 of the positive electrode 3 is smaller than the width W1 of the negative electrode 5. The difference between the width W1 of the negative electrode 5 and the width W2 of the positive electrode 3 is in the range of 0.2mm ≤ W1 - W2 ≤ 0.6mm. In one embodiment, the difference between W1 and W2 can be 0.2mm, 0.22mm, 0.24mm, 0.26mm, 0.28mm, 0.3mm, 0.32mm, 0.34mm, 0.36mm, 0.38mm, 0.4mm, 0.42mm, 0.44mm, 0.46mm, 0.48mm, 0.5mm, 0.52mm, 0.54mm, 0.56mm, 0.58mm, 0.6mm, etc., which will not be listed here.

[0057] The greater the difference between the width W1 of the negative electrode 5 and the width W2 of the positive electrode 3, the better the effect of preventing lithium plating, avoiding short circuits, and improving the process fault tolerance, but the energy density of the battery cell is relatively small; the smaller the difference between the width W1 of the negative electrode 5 and the width W2 of the positive electrode 3, the greater the energy density of the battery cell.

[0058] Furthermore, in the lateral direction of the space within the outer casing 100, the inner diameter of the bottom shell 1 is D1, and the diameter of the core 200 is D2. The ratio between D2 and D1 is in the range of 0.95 ≤ D2 / D1 ≤ 0.99. In one embodiment, the ratio between D2 and D1 can be 0.95, 0.96, 0.97, 0.98, 0.99, etc., which will not be listed here.

[0059] The smaller the ratio between D2 and D1, the smaller the diameter of the core 200, the larger the space reserved in the lateral direction of the core 200 in the outer casing 100, but the relatively lower the energy density of the battery cell. The larger the ratio between D2 and D1, the larger the diameter of the core 200, the smaller the space reserved in the lateral direction of the core 200 in the outer casing 100, and the relatively higher the energy density of the battery cell.

[0060] During the winding process of the positive electrode 3, separator 4, and negative electrode 5, the separator 4 is first wound separately using the winding needle 300 to form a separator pre-wound portion 201, and then the positive electrode 3, separator 4, and negative electrode 5 are wound together. In other words, the winding core 200 has a separator pre-wound portion 201, which is formed by winding the separator 4. The diameter of the separator pre-wound portion 201 is D4, and the ratio between D4 and D1 is in the range of 0.15 ≤ D4 / D1 ≤ 0.2. In one embodiment, the ratio between D4 and D1 can be 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, etc., which will not be listed here.

[0061] The larger the ratio between D4 and D1, the larger the diameter of the pre-wound section 201 of the separator, the stronger the overall compressive strength of the core 200, and the less likely the core 200 is to loosen or deform. This reduces the number of internal short circuit points in the core 200 and improves the safety performance of the battery cell, but the energy density of the core 200 is relatively low. Conversely, the smaller the ratio between D4 and D1, the smaller the diameter of the pre-wound section 201 of the separator, the smaller the overall compressive strength of the core 200, but the energy density of the core 200 will increase.

[0062] In one embodiment, the diameter of the winding needle 300 for winding the positive electrode 3, the separator 4, and the negative electrode 5 is D3, and the ratio between D3 and D1 is in the range of 0.1 ≤ D3 / D1 ≤ 0.15. In one embodiment, the ratio between D3 and D1 can be 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, etc., which will not be listed here. The diameter of the winding needle 300 can affect the minimum diameter of the separator pre-winding section 201, so as to precisely control the diameter of the separator pre-winding section 201 and better balance the compressive strength and energy density of the core 200.

[0063] The negative electrode tab 203 and positive electrode tab 202 of the core 200 are both located at one end of the core 200 near the cover plate assembly. On the one hand, this facilitates the connection between the negative electrode tab 203 and positive electrode tab 202 of the core 200 and the outer casing 100. On the other hand, it avoids the negative electrode tab 203 occupying space in the height direction of the core 200, improves the utilization rate of the inner cavity of the bottom casing 1, and thus improves the volumetric energy density of the battery cell.

[0064] Furthermore, the cover plate assembly includes a cover plate 21 and a pole post 22. The cover plate 21 has a through hole, the pole post 22 passes through the through hole and forms an upper pole post 221 on the outside of the cover plate 21, and a lower pole post 222 is formed on the inside of the cover plate 21. The free end of the positive electrode tab 202 of the core 200 is fixedly connected to the lower pole post 222, and the free end of the negative electrode tab 203 is fixedly connected to the cover plate 21 and the bottom shell 1 to realize the electrical connection between the core 200 and the outer shell 100.

[0065] It should be noted that, since the lower electrode post 222 of the electrode post 22 protrudes from the inner surface of the cover plate 21 and has a certain height dimension in the direction of the battery cell height, the effective space height H1 inside the casing 100 preferably refers to the distance between the inner surface of the bottom wall of the bottom shell 1 and the end face of the lower electrode post 222 near the core 200 (hereinafter referred to as the lower end face of the lower electrode post 222). Furthermore, when the positive electrode tab 202 is welded to the lower end face of the lower electrode post 222, the welding position will inevitably protrude from the lower end face of the lower electrode post 222. Therefore, the effective space height H1 inside the casing 100 is further preferably referred to as the minimum distance between the inner surface of the bottom wall of the bottom shell 1 and the welding position between the lower electrode post 222 and the positive electrode tab 202.

[0066] The diameter of the upper electrode post 221 is D5, and the ratio between D5 and D1 ranges from 0.2 to 0.5. In one embodiment, the ratio between D5 and D1 can be 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, etc., which will not be listed here. The small diameter of the upper electrode post 221 is beneficial for the installation of battery cells, improves the overall space utilization, and thus increases the volumetric energy density.

[0067] The diameter of the lower electrode post 222 is D6, and the ratio between D6 and D1 is in the range of 0.6 ≤ D6 / D1 ≤ 0.9. In one embodiment, the ratio between D6 and D1 can be 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, etc., which will not be listed here. The large diameter of the lower electrode post 222 is beneficial to increasing the contact area between the lower electrode post 222 and the core 200 when the battery cell is subjected to external mechanical abuse (such as planar extrusion). According to the pressure formula (P = F / S), the larger the contact area, the smaller the pressure on the core 200, and therefore the less damage to the core 200, resulting in fewer internal short circuit points and improving the safety performance of the battery cell.

[0068] In summary, the battery cell provided in this application improves the problem of poor safety performance of high energy density batteries by using specific size designs for the positive electrode 3, negative electrode 5, core 200, bottom shell 1, and cover plate assembly. While maintaining the original high energy density, it greatly improves the safety performance of the battery cell, especially improving the safety problems caused by external mechanical abuse (such as planar extrusion).

[0069] To verify the safety performance of the battery cell provided in this application under different design parameters, this application conducted multiple tests, as detailed in Table 1.

[0070] Table 1. Planar extrusion test of individual battery cells

[0071]

[0072]

[0073] The foregoing has shown and described the basic principles, main features, and advantages of this application. Those skilled in the art should understand that the above embodiments do not limit this application in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of this application.

Claims

1. A battery cell, characterized by, include: The outer shell (100) includes a bottom shell (1) and a cover plate assembly. One end of the bottom shell (1) is closed and the other end is open to form an opening. The cover plate assembly is sealed and covered at the opening. The minimum distance from the inner surface of the bottom wall of the bottom shell (1) to the inner surface of the cover plate assembly is H1. The core (200) is formed by winding a positive electrode sheet (3), a separator (4) and a negative electrode sheet (5). The width of the negative electrode sheet (5) is W1, and the ratio between W1 and H1 is in the range of 0.8≤W1 / H1≤0.

9.

2. The battery cell of claim 1, wherein, The width W1 of the negative electrode (5) is greater than the width W2 of the positive electrode (3) of the core (200) and less than the width W3 of the diaphragm (4) of the core (200). The height of the core (200) is H2, and the ratio between H2 and H1 is in the range of 0.9≤H2 / H1≤0.

95.

3. The battery cell of claim 2, wherein, Before the core (200) is formed, the difference between the width W3 of the diaphragm (4) and the width W1 of the negative electrode sheet (5) is in the range of: 1mm ≤ W3 - W1 ≤ 2mm; and / or, The difference between the width W1 of the negative electrode (5) and the width W2 of the positive electrode (3) is: 0.2mm≤W1-W2≤0.6mm.

4. The battery cell of claim 1, wherein, The inner diameter of the bottom shell (1) is D1, the diameter of the core (200) is D2, and the ratio between D2 and D1 is in the range of 0.95≤D2 / D1≤0.

99.

5. The battery cell of claim 4, wherein, The core (200) has a pre-wound portion (201) of a diaphragm (4), which is formed by winding the diaphragm (4). The diameter of the pre-wound portion (201) of the diaphragm (4) is D4, and the ratio between D4 and D1 is in the range of 0.15≤D4 / D1≤0.

2.

6. The battery cell of claim 4, wherein, The diameter of the winding needle (300) for winding the positive electrode (3), the separator (4) and the negative electrode (5) is D3, and the ratio between D3 and D1 is in the range of 0.1≤D3 / D1≤0.

15.

7. The battery cell of claim 1, wherein, The negative tab (203) and the positive tab (202) of the core (200) are both located at one end of the core (200) near the cover plate assembly.

8. The battery cell of claim 7, wherein, The cover plate assembly includes a cover plate (21) and a pole post (22). The cover plate (21) has a through hole. The pole post (22) passes through the through hole and forms an upper pole post (221) on the outside of the cover plate (21). A lower pole post (222) is formed on the inside of the cover plate (21). The free end of the positive electrode tab (202) is fixedly connected to the lower pole post (222). The free end of the negative electrode tab (203) is fixedly connected to the cover plate (21) and the bottom shell (1).

9. The battery cell of claim 8, wherein, The inner diameter of the bottom shell is D1, the diameter of the upper pole post (221) is D5, and the ratio between D5 and D1 is in the range of 0.2≤D5 / D1≤0.5; and / or, the diameter of the lower pole post (222) is D6, and the ratio between D6 and D1 is in the range of 0.6≤D6 / D1≤0.

9.

10. The battery cell of any one of claims 1-9, wherein, D1 > H1; or, D1 < H1.

11. A battery, characterized by Includes the battery cell as described in any one of claims 1-10.

12. An electrical device, characterized by Includes the battery as described in claim 11.

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