Battery cell, battery and power utilization device

Abstract

The utility model discloses a battery cell which comprises a roll core, and the outer contour of the projection of two ends of the roll core along a first direction along a second direction is arc-shaped; the size of the roll core in the third direction is W, and the size of the roll core in the first direction is L; wherein the circle center of the arc is located on the side, close to the roll core, of the arc, the radius of the arc is R2, and R2 is larger than 1 / 2W and smaller than or equal to 1 / 2L; or the circle center of the arc is positioned on one side of the arc deviating from the roll core. Therefore, according to the battery cell, the arc radius of the roll core is limited, so that the situation that the hot pressing effect is not enough due to overlarge radius is avoided; meanwhile, the situations that powder falls off from the side edge area of the battery cell and the side edge of the battery cell is wrinkled due to the too small radius are avoided. The utility model also discloses a battery and an electric device.

Description

Technical Field

[0001] The utility model relates to the technical field of lithium ion batteries, in particular to an electric core, a battery provided with the electric core, and an electric device provided with the battery. Background Art

[0002] In recent years, as the world has focused on energy consumption and environmental issues, lithium-ion batteries have rapidly become the new favorite of consumer electronics, energy storage systems, power systems, etc. due to their high specific energy. At the same time, lithium-ion batteries have the advantages of high volume specific energy, high energy conversion efficiency, and green environmental protection. They can not only improve the efficiency of new energy utilization, but also reduce environmental pollution caused by fossil energy consumption and improve air quality.

[0003] The preparation process of lithium-ion batteries usually includes a hot pressing step to reduce the thickness of the battery cell. However, the hot pressing work will cause the sides of the battery cell to deform, and wrinkles will easily form on the side areas of the battery cell, increasing the probability of powder loss in this area and posing a risk of lithium plating. Utility Model Content

[0004] In view of this, the purpose of the utility model is to provide a battery cell, a battery and an electrical device, which can solve the problem that wrinkles are easily formed in the side area of ​​the battery cell, the probability of powder loss in this area is increased, and there is a risk of lithium plating.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] A battery core comprises a winding core, wherein the outer contour of the projection of two ends of the winding core along a first direction along a second direction is an arc;

[0007] The dimension of the winding core along the third direction is W, and the dimension of the winding core along the first direction is L;

[0008] The center of the arc is located on a side of the arc close to the winding core, the radius of the arc is R2, and 1 / 2W<R2≤1 / 2L;

[0009] Alternatively, the center of the arc is located on a side of the arc away from the winding core.

[0010] Optionally, in the above battery cell, the center of the arc is located on a side of the arc away from the winding core, and the radius of the arc is R1, 1 / 2L≤R1≤L.

[0011] Optionally, in the above-mentioned battery cell, along the first direction, the distance between the bending point of the arc and the winding tail of the winding core is A, and 0<A<1 / 2L.

[0012] Optionally, in the above battery cell, the center of the arc is located on a side of the arc away from the winding core, 1 / 6L<W<2 / 3L and / or 1 / 10W<R1<1 / 3W.

[0013] Optionally, in the above-mentioned battery cell, the first pole lug and the second pole lug of the winding core are respectively located on both sides or the same side of the winding axis of the winding core, and the number of winding layers of the winding core is M;

[0014] Wherein, the number of the first tabs is N1, 1 / 2M≤N1≤M;

[0015] And / or, the number of the second electrode tabs is N2, 1 / 2M≤N2≤M.

[0016] Optionally, in the above-mentioned battery cell, the projection of the first electrode tab along the third direction is a quadrilateral or a triangle;

[0017] And / or, the projection of the second pole ear along the third direction is a quadrilateral or a triangle.

[0018] Optionally, in the above-mentioned battery core, a first pole piece, a diaphragm and a second pole piece are wound to form the core;

[0019] Wherein, the first pole piece includes a first current collector and a first active material coating located on the surface of the first current collector, and the thickness of the first pole piece is 50 μm-500 μm;

[0020] And / or, the second pole piece includes a second current collector and a second active material coating located on the surface of the second current collector, and the thickness of the second pole piece is 50 μm-500 μm.

[0021] Optionally, in the above battery cell, the first pole piece, the second pole piece and the diaphragm are all of uniform thickness.

[0022] A battery comprises the above-mentioned battery cell.

[0023] An electrical device comprises the above-mentioned battery.

[0024] It can be seen from the above technical scheme that in the battery cell of the utility model, when the center of the arc is located on the side of the arc close to the winding core (that is, the arc is convex outward), the radius of the arc of the winding core is limited to avoid the radius being too large to cause insufficient hot pressing effect; at the same time, avoid the situation where the radius is too small to cause powder loss in the side area of ​​the battery cell and wrinkles on the side of the battery cell; when the center of the arc is located on the side of the arc away from the winding core (that is, the arc is concave inward), on the basis of being able to avoid powder loss, the energy density of the battery cell can also be improved due to the inward concave. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 It is a cross-sectional view of a battery cell in the prior art;

[0027] Figure 2 A cross-sectional view of an arc-shaped concave battery cell provided in an embodiment of the utility model;

[0028] Figure 3 A cross-sectional view of a curved convex battery cell provided in an embodiment of the utility model;

[0029] Figure 4 A schematic diagram of the position of the tabs of the battery cell provided in an embodiment of the utility model;

[0030] Figure 5 A schematic diagram of the shape of the pole ear provided in an embodiment of the utility model;

[0031] Figure 6a A schematic diagram of the structure of the arc-shaped concave pressing device provided in an embodiment of the utility model;

[0032] Figure 6b for Figure 6a Front view of the side pressure plate in;

[0033] Figure 7a A schematic diagram of the structure of the arc-shaped convex pressing device provided in an embodiment of the utility model;

[0034] Figure 7b for Figure 7a Front view of the side pressure plate in.

[0035] in:

[0036] 1-first pole piece, 2-diaphragm, 3-second pole piece, 4-first pole ear, 5-second pole ear,

[0037] 61-upper pressure plate, 62-upper pressure plate power mechanism, 63-side pressure plate, 64-side pressure plate power mechanism,

[0038] 65-bottom fixing plate, 66-connecting column, 67-fixing plate, 68-guide bearing, 69-bottom plate. DETAILED DESCRIPTION

[0039] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0040] In the description of the utility model, it should be noted that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the utility model product is usually placed when in use, and are only for the convenience of describing the utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the utility model. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0041] like Figure 2-Figure 5 As shown, an embodiment of the utility model provides a battery cell.

[0042] First, the battery cell includes a winding core, the outer contour of the projection of the two ends of the winding core along the first direction along the second direction is an arc; the size of the winding core along the third direction is W, and the size of the winding core along the first direction is L; wherein, see Figure 3 , the center of the arc is located on the side of the arc close to the winding core (that is, the arc bulges outward to form a convex area), the radius of the arc is R2, 1 / 2W<R2≤1 / 2L; or, see Figure 2 , the center of the arc is located on the side of the arc away from the winding core (that is, the arc is concave inward to form a concave area). It should be noted that the first direction is the width direction of the battery cell, see Figure 1 The m direction in the figure; the third direction is the thickness direction of the cell, see Figure 1 The second direction is the direction perpendicular to the plane where the width and thickness of the battery core are located (i.e., the direction parallel to the winding direction of the core). The core includes a bent section and a straight section. The arc specifically refers to the outermost bent section of the core winding. Figure 1 and Figure 2 Two types of batteries and Figure 1 and Figure 3 It can be seen from the two batteries that compared with Figure 1 , Figure 2 and Figure 3The cross-sectional area of ​​the battery cell can be reduced by S = (L1-L) × W, where L1 is the width of the battery cell structure after hot pressing without side limitation, which is equivalent to reducing the space waste of the battery cell and improving the energy density of the battery.

[0043] It can be seen that for the battery cell provided by the embodiment of the utility model, when the center of the arc is located on the side of the arc close to the winding core (that is, the arc is convex outward), the radius of the arc of the winding core is limited to avoid the radius being too large to cause insufficient hot pressing effect; at the same time, it is avoided that the radius is too small to cause powder loss in the side area of ​​the battery cell and wrinkles on the side of the battery cell; when the center of the arc is located on the side of the arc away from the winding core (that is, the arc is concave inward), on the basis of avoiding powder loss, the energy density of the battery cell can also be improved due to the inward concave.

[0044] In a specific implementation, the center of the arc is located on the side of the arc away from the winding core (i.e., the arc is concave inwardly), and the radius of the arc is R1, 1 / 2L≤R1≤L. When the arc is concave inwardly, by limiting the radius of the arc of the winding core, the energy density of the battery cell can be improved while avoiding powder loss.

[0045] In specific implementation, along the first direction, the distance between the starting point of the arc (i.e., the connection position between the outermost bending section and the straight section of the winding core) and the winding tail of the core is A, 0<A<1 / 2L. When the arc is concave inward, the distance between the end of the pole piece of the core and the concave area is 0<A<1 / 2L, avoiding A greater than 1 / 2L will cause energy density loss, and avoiding A less than 0 will make the end of the core located in the concave area, resulting in an increase in the width of the core after hot pressing, affecting the core into the shell.

[0046] When the arc is convex outward, the distance between the end of the pole piece of the core and the convex area is 0<A<1 / 2L. Avoiding A greater than 1 / 2L will cause a loss of energy density. At the same time, avoiding A less than 0 will make the end of the pole piece located in the concave area, resulting in an increase in the width of the core after hot pressing, affecting the core's entry into the shell.

[0047] In specific implementation, the center of the arc is located on the side of the arc away from the core, 1 / 6L<W<2 / 3L to avoid the concave area being too large, causing the entire core to deform during the hot pressing process, and / or 1 / 10W<R1<1 / 3W to avoid excessive accumulation of electrolyte in the concave area, causing the charge and discharge performance of the core to be affected.

[0048] In a specific implementation, the first pole lug 4 and the second pole lug 5 of the winding core are respectively located on both sides or the same side of the winding axis of the winding core, and the number of winding layers of the winding core is M; wherein, the number of the first pole lugs 4 is N1, 1 / 2M≤N1≤M; and / or, the number of the second pole lugs 5 is N2, 1 / 2M≤N2≤M. The first pole lug 4 and the second pole lug 5 have opposite polarities. When the first pole lug 4 is a positive pole lug, the second pole lug 5 is a negative pole lug; when the first pole lug 4 is a negative pole lug, the second pole lug 5 is a positive pole lug. The pole lug is a metal sheet that is led out from the pole piece and used to connect to an external circuit and conduct current. The pole lugs are located on both sides of the winding axis (i.e., the surface pole lugs), which enables current to flow in and out from both sides of the winding core, and the current conduction path is short and uniform, which is conducive to reducing internal resistance and improving the charging and discharging efficiency and power density of the battery. The pole lugs on both sides can more effectively disperse the heat generated inside to the battery housing or the external cooling system, which helps to improve the thermal management of the battery and improve the safety and service life of the battery. In addition, the double-sided tabs facilitate the series and parallel connection in the battery module or battery pack, and the connection mode can be flexibly adjusted as needed to adapt to applications with different voltage and capacity requirements. The tabs are located on the same side of the winding axis (i.e., single-sided tabs), which can simplify the wiring and connection in the battery module or battery pack, reduce the use of welding points and conductive materials, and help reduce manufacturing costs and improve production efficiency. For space-constrained applications (such as smartphones, drones, etc.), single-sided tabs can reduce battery thickness, improve space utilization, and help achieve miniaturization and lightweight of equipment. In addition, the single-sided tab design is more suitable for certain specific packaging forms, such as pouch cells, which have flexible packaging and are easy to implement single-sided tab layout. In addition, multi-tabs can disperse the current path to multiple connection points, shorten the current path length, and significantly reduce internal resistance. Low internal resistance is conducive to improving charging and discharging efficiency, reducing heat generation, and improving the power performance and energy efficiency of the battery. In addition, multi-tabs can make the current distribution more uniform, reduce the formation of local hot spots, and help improve the thermal management of the battery, and improve the safety and service life of the battery. Moreover, limiting the number of tabs can not only avoid the problem of a longer current path and relatively large internal resistance caused by a small number of tabs. High internal resistance will reduce the charging and discharging efficiency of the battery, especially when charging and discharging with large currents, which may cause serious heating of the battery and affect battery performance and life; it can also avoid the high current density at the tabs caused by a small number of tabs, which easily forms hot spots and poses challenges to the thermal management of the battery. It is necessary to strengthen the local heat dissipation design in a targeted manner to prevent safety problems caused by overheating. The specific number of tabs can be specifically designed by technicians in this field according to actual needs.

[0049] During specific implementation, the projection of the first pole ear 4 along the third direction is a quadrilateral or a triangle; and / or, the projection of the second pole ear 5 along the third direction is a quadrilateral or a triangle, but it is not limited thereto. The projection of the pole ear along the third direction can also be a polygon, or an arc shape. The specific shape can be specifically designed by those skilled in the art according to actual needs. The pole ear is rectangular, simple to process, easy to cut and weld, and suitable for mass automated production. It is easy to attach to the edge of the pole piece, takes up less space, and is conducive to improving the energy density of the battery. The rounded edge of the arc-shaped pole ear is conducive to reducing stress concentration and can reduce the risk of pole ear breakage.

[0050] In the specific implementation, it includes a first pole piece 1, a diaphragm 2 and a second pole piece 3 wound to form a winding core; wherein the first pole piece 1 includes a first current collector and a first active material coating located on the surface of the first current collector, and the thickness of the first pole piece 1 is 50μm-500μm; and / or, the second pole piece 3 includes a second current collector and a second active material coating located on the surface of the second current collector, and the thickness of the second pole piece 3 is 50μm-500μm. The restriction on the thickness of the pole piece can not only avoid the occurrence of problems such as the low mechanical strength of the pole piece and the difficulty in manufacturing due to the pole piece being too thin, the possible increase in the internal resistance of the battery, the aggravation of side reactions, the increase in thermal management challenges, the increase in cost and the decrease in safety; at the same time, it can avoid the occurrence of problems such as the reduced energy density of the battery, the increase in internal resistance, the difficulty in heat dissipation, the increase in manufacturing costs, the generation of mechanical stress, the difficulty in ensuring the consistency of the pole piece and the increase in safety risks due to the pole piece being too thick. The thickness of the pole piece needs to comprehensively consider multiple factors such as the energy density, charge and discharge performance, manufacturing process and cost, and safety of the battery, and be optimized and designed according to specific application requirements. Therefore, the specific thickness of the pole piece can be specifically designed by those skilled in the art according to actual needs.

[0051] In specific implementation, the first pole piece 1, the second pole piece 3 and the diaphragm 2 are all of uniform thickness (i.e., the thickness of each of the three is uniform and consistent). The pole piece and the diaphragm 2 of uniform thickness can ensure that the contact area between the active material and the electrolyte, the ion transmission path and the charge transfer rate are basically consistent everywhere inside the battery, which is conducive to the uniform electrochemical reaction and improves the battery charging and discharging efficiency, power performance and cycle stability. It can avoid the increase of local internal resistance, ensure that the current is evenly distributed inside the pole piece and between the pole piece and the diaphragm 2, reduce ohmic loss, especially at high rate charging and discharging, which is conducive to maintaining the instantaneous power output of the battery. Uneven thickness may lead to local overheating, lithium precipitation, short circuit and other safety risks. Uniform thickness helps to reduce such hidden dangers and enhance battery safety. It can also ensure that the active material is fully utilized, avoid the active material not being fully utilized due to local thinness, or the internal lithium ion transmission being blocked due to local thickness, and the active material cannot fully react, thereby improving the battery capacity utilization rate. It can reduce local stress concentration, prevent the electrode material from pulverizing and falling off, maintain the battery cycle stability, and extend the service life.

[0052] In the specific implementation, see Figures 6 and 7 for details. The hot pressing of the battery cell is completed by a hot pressing device, which includes an upper pressure plate 61, an upper pressure plate power mechanism 62, a side pressure plate 63, a side pressure plate power mechanism 64, a bottom fixed plate 65, a connecting column 66, a fixed plate 67, a guide bearing 68, and a bottom plate 69, wherein the bottom fixed plate 65, two side pressure plates 63 and an upper pressure plate 61 constitute a hot pressing area; the upper pressure plate power mechanism 62 can drive the upper pressure plate 61 to move in the vertical direction; the side pressure plate power mechanism 64 can push the side pressure plate 63 to move in a direction perpendicular to the vertical direction; the bottom fixed plate 65 is arranged on the bottom plate 69 and is used to place the battery cell to be hot pressed; the fixed plate 67 is used to connect the upper pressure plate power mechanism 62; the two ends of the connecting column 66 are respectively connected to the fixed plate 67 and the bottom plate 69, and the middle part of the connection part passes through the guide bearing 68; the side pressure plate power mechanism 64 is arranged on the connecting column 66. In order to match different battery cell thicknesses, see for details Figure 6b , the radius R1 of the arc of the different concave areas is obtained, and the radius R3 of the convex arc section of the side hot pressing block can be adjusted by changing the shape. In order to match different battery cell thicknesses, see Figure 7b , the radius R2 of the arc of different convex areas is obtained, and the radius R4 of the concave arc segment of the side hot pressing block can be adjusted by changing the shape.

[0053] In specific implementation, the preparation of the battery cell includes:

[0054] The core to be pressed is placed in the hot pressing area of ​​the hot pressing device, and one side of the core to be pressed parallel to the straight section of the pole piece contacts the bottom fixing plate 65. At this time, the core to be pressed maintains a certain distance from the side pressing plate 63. In order to make the core to be pressed evenly pressed, it should be placed in the center with the same distance from the side pressing plates 63 on both sides;

[0055] The battery cell is shaped and hot pressed by hot pressing. After the battery cell is placed in place, the upper pressing plate 61 is driven by the upper pressing plate power mechanism 62 to press the battery cell downward. After the thickness direction of the pressed battery cell is compressed, the arcs on both sides protrude to the sides and contact the side pressing plates 63.

[0056] After the pressure of the upper pressure plate 61 is in place, the two side pressure plates 63 move toward the battery core under the drive of the side pressure plate power mechanism 64, thereby squeezing the battery core. During the hot pressing process, the force on the battery core comes from the upper pressure plate 61 and the two side pressure plates 63, that is, the thickness and width directions of the battery core are all squeezed. At the same time, by adjusting the radius of the arc segment of the pressure measuring block, the radius of the arc of the battery core can be adjusted. For battery cells with relatively fragile pole pieces, the bending of the core is prone to powder loss or even breakage during hot pressing shaping, which will lead to limited electron transmission and increase the internal resistance of the battery. Therefore, the hot pressing of the core requires the hot pressing shaping pressure to be as small as possible and the time to be as short as possible. However, hot pressing shaping must shape the core, the core thickness must meet the process requirements, the core elasticity must be reduced, and the consistency of the core thickness must be ensured. Therefore, the two-step hot pressing method can avoid excessive bending and deformation of the internal core, reduce the probability of pole piece breakage and wrinkling, and effectively reduce the possibility of powder loss and lithium precipitation. Furthermore, the method can reduce the time of hot pressing shaping;

[0057] The pressure is maintained at a constant temperature for a certain period of time to complete the preparation of the battery cell. During the hot pressing process, the hot pressing effect of the pole piece can be changed by adjusting the hot pressing parameters. In this embodiment, the hot pressing moving speed of the upper pressing plate 61 and the side pressing plate 63 is in the range of 5-2500mm / min, the hot pressing temperature is between 50-100℃, the pressure is maintained at 2-6T, and the hot pressing time is in the range of 20-200s.

[0058] An embodiment of the utility model provides a battery, comprising the above-mentioned battery cell.

[0059] It can be seen that the battery provided by the embodiment of the utility model limits the radius of the arc of the winding core to avoid the situation where the radius is too large, resulting in insufficient hot pressing effect and failure to reduce the thickness of the battery cell; at the same time, it avoids the situation where the radius is too small, resulting in powder falling off the side area of ​​the battery cell and wrinkles on the side of the battery cell.

[0060] An embodiment of the utility model provides an electrical device, including the above-mentioned battery. By limiting the numerical value of the arc radius of the winding core of the battery in the electrical device, it is possible to avoid the situation where the radius is too large, resulting in insufficient hot pressing effect and failure to reduce the thickness of the battery cell; at the same time, it is possible to avoid the situation where the radius is too small, resulting in powder falling off the side area of ​​the battery cell and wrinkles on the side of the battery cell.

[0061] The electrical device of the utility model is not particularly limited, and may include but is not limited to: laptop computers, pen-input computers, mobile computers, e-book players, portable phones, portable fax machines, portable copiers, portable printers, head-mounted stereo headphones, video recorders, LCD televisions, portable cleaners, portable CD players, mini CDs, transceivers, electronic notepads, calculators, memory cards, portable recorders, radios, backup power supplies, motors, cars, motorcycles, power-assisted bicycles, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries and lithium-ion capacitors, etc.

[0062] Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the presence of other identical elements in the process, method, article or device including the elements.

[0063] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0064] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A battery cell, characterized in that: It comprises a winding core, wherein the outer contour of the projection of two ends of the winding core along the first direction along the second direction is an arc; The dimension of the winding core along the third direction is W, and the dimension of the winding core along the first direction is L; The center of the arc is located on a side of the arc close to the winding core, the radius of the arc is R2, and 1 / 2W<R2≤1 / 2L; Alternatively, the center of the arc is located on a side of the arc away from the winding core.

2. The battery cell according to claim 1, characterized in that: The center of the arc is located at a side of the arc away from the winding core, and the radius of the arc is R1, 1 / 2L≤R1≤L.

3. The battery cell according to claim 1, characterized in that: Along the first direction, the distance between the starting point of the arc and the winding tail of the winding core is A, and 0<A<1 / 2L.

4. The battery cell according to claim 1, characterized in that: The center of the arc is located at a side of the arc away from the winding core, 1 / 6L<W<2 / 3L and / or 1 / 10W<R1<1 / 3W.

5. The battery cell according to claim 1, characterized in that: The first pole lug (4) and the second pole lug (5) of the winding core are respectively located on two sides or on the same side of the winding axis of the winding core, and the number of winding layers of the winding core is M; The number of the first pole tabs (4) is N1, 1 / 2M≤N1≤M; And / or, the number of the second pole tabs (5) is N2, 1 / 2M≤N2≤M.

6. The battery cell according to claim 5, characterized in that: The projection of the first pole lug (4) along the third direction is a quadrilateral or a triangle; And / or, the projection of the second pole lug (5) along the third direction is a quadrilateral or a triangle.

7. The battery cell according to claim 1, characterized in that: It comprises a first pole piece (1), a diaphragm (2) and a second pole piece (3) which are wound to form the winding core; The first pole piece (1) comprises a first current collector and a first active material coating located on the surface of the first current collector, and the thickness of the first pole piece (1) is 50 μm-500 μm; And / or, the second pole piece (3) comprises a second current collector and a second active material coating located on the surface of the second current collector, and the thickness of the second pole piece (3) is 50 μm-500 μm.

8. The battery cell according to claim 7, characterized in that: The first pole piece (1), the second pole piece (3) and the diaphragm (2) all have uniform thickness.

9. A battery, characterized in that: A battery cell comprising any one of claims 1 to 8.

10. An electrical device, characterized in that: A battery comprising the battery of claim 9.

Images