Roll core, battery cell and electric equipment
By controlling the relationship between the thickness of the electrode assembly and the height of the tab, and combining the tabless section and the tilted tab design, the problems of the tab covering the center hole and the poor soldering of the cylindrical cell were solved, thus improving the welding reliability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-24
- Publication Date
- 2026-04-03
AI Technical Summary
The tabs of existing cylindrical cells are large in size in the winding direction, which causes them to cover the center hole and are prone to poor soldering, affecting the reliability of the soldering.
By setting the thickness relationship of the electrode assembly, the height of the electrode tabs is controlled to avoid obscuring the central hole and to reduce the occupancy of the electrode tabs on the axial space of the cylinder. The use of a tabless section design and an inclined electrode tab structure facilitates the welding of the current collector.
This effectively prevents the electrode tab from covering the center hole, reduces the space occupied by the electrode tab, improves welding reliability, avoids incomplete welding, and enhances the welding effect.
Smart Images
Figure CN224082458U_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of batteries, specifically to a winding core, a battery cell, and an electrical device. Background Technology
[0002] Battery cells come in various forms, such as prismatic cells and cylindrical cells. Cylindrical cells are formed by winding electrode assemblies, with the tabs at both ends needing to be bent inwards and flattened for welding to the current collector. In existing technologies, cylindrical cells often use all tabs. Due to the large number of winding layers, the overall size of the tabs in the winding direction is large. The stacked layers of tabs result in a relatively large overall thickness and volume. The tabs occupy a significant amount of space at the ends of the cell. This makes it difficult to flatten the tabs, as they can easily obscure the center hole, and also makes it difficult to flatten them completely. Furthermore, it can easily lead to incomplete soldering problems when welding the tabs to the current collector. Utility Model Content
[0003] The purpose of this disclosure is to solve, or at least partially solve, the problems described above.
[0004] To achieve the above objectives, this disclosure provides a winding core comprising a multi-layer electrode assembly arranged sequentially in a radial direction. The electrode assembly includes a negative electrode, a first diaphragm, a positive electrode, and a second diaphragm arranged sequentially in a radially outward direction. The positive electrode includes a positive current collector and a positive tab connected to a first end of the positive current collector in the axial direction. The negative electrode includes a negative current collector and a negative tab connected to a second end of the negative current collector in the axial direction. In the N+1th layer of the electrode assembly in the radially outward direction, the height h of the positive tab is... N Satisfy: h N+1 <(2t1+t2+t3)×N+t1+t3; and / or, the height H of the negative electrode ear N Satisfy: H N+1 <(2t1+t2+t3)×N, where t1 is the thickness of the first membrane or the second membrane, t2 is the thickness of the positive electrode, t3 is the thickness of the negative electrode, and N is a positive integer.
[0005] In some embodiments, the height of the positive electrode tab satisfies: h N <h N+1 <h N +2t1+t3, and 2t1+t3 <h N+1 .
[0006] In some embodiments, the height of the negative electrode tab satisfies: H N <H N+1 <H N +2t1+t2, and 2t1+t2 <H N+1 .
[0007] In some embodiments, multiple electrode assemblies are sequentially connected to form a wound structure. The portion of the electrode assembly near the center hole of the winding core is set as a first electrodeless tab segment. In the first electrodeless tab segment, the positive electrode does not have a positive tab, and / or the negative electrode does not have a negative tab.
[0008] In some embodiments, the length of the first electrodeless ear segment is 200-300mm.
[0009] In some embodiments, multiple electrode assemblies are sequentially connected to form a wound structure, and the outermost portion of the electrode assembly located on the core is set as a second electrodeless tab section. In the second electrodeless tab section, the positive electrode does not have a positive tab, and / or the negative electrode does not have a negative tab.
[0010] In some embodiments, the length of the second electrodeless ear segment is 200-300mm.
[0011] In some embodiments, multiple electrode assemblies are connected in sequence to form a wound structure, and the positive electrode tab and / or the negative electrode tab are inclined in the winding direction of the electrode assembly.
[0012] In some embodiments, the angle between the positive electrode tab and / or the negative electrode tab and the winding direction is 30-80°.
[0013] On the other hand, this disclosure provides a battery cell including a housing and a winding core as described above, the winding core being disposed within the housing.
[0014] In another aspect, this disclosure provides an electrical device including the aforementioned battery cell.
[0015] By setting the dimensional relationship between the thickness of the first or second diaphragm, the thickness of the positive electrode plate and the thickness of the negative electrode plate, and the height of the positive or negative electrode tab, the electrode tab is prevented from being flattened and covering the central hole, the electrode tab occupies less space in the axial direction of the cylinder, facilitates the welding of the current collector, avoids incomplete welding, and improves welding reliability. Attached Figure Description
[0016] Figure 1 This is a cross-sectional view of the winding core according to an embodiment of this disclosure;
[0017] Figure 2 yes Figure 1 A magnified view of part A;
[0018] Figure 3 This is a partial structural schematic diagram of the negative electrode sheet according to an embodiment of the present disclosure;
[0019] Figure 4 This is a partial structural schematic diagram of the positive electrode sheet according to an embodiment of the present disclosure;
[0020] Figure 5 This is a schematic diagram of the tilt angle of the tab in the positive electrode sheet of this disclosure embodiment.
[0021] Explanation of reference numerals in the attached figures
[0022] 1-Central hole, 2-First diaphragm, 3-Negative electrode plate, 4-Positive electrode plate, 5-Second diaphragm, 31-Negative active layer, 32-Negative current collector, 33-Negative tab, 41-Positive active layer, 42-Positive current collector, 43-Positive tab. Detailed Implementation
[0023] The embodiments of this disclosure will be further described in detail below with reference to the accompanying drawings and examples. The detailed description of the embodiments and the accompanying drawings are used to illustrate the principles of this disclosure by way of example, but should not be used to limit the scope of this disclosure. This disclosure can be implemented in many different forms and is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.
[0024] These embodiments are provided to make the disclosure thorough and complete, and to fully express the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, material composition, numerical expressions, and values set forth in these embodiments should be interpreted as exemplary only and not as limiting.
[0025] It should be noted that, in the description of this disclosure, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," and "outer," etc., indicating orientation or positional relationship, are only for the convenience of describing this disclosure 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, and therefore should not be construed as a limitation of this disclosure. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.
[0026] Furthermore, the terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. "Vertical" is not strictly vertical, but within the permissible margin of error. "Parallel" is not strictly parallel, but within the permissible margin of error. Terms such as "including" or "contains" mean that the element preceding the word encompasses the element listed after the word, and do not exclude the possibility of encompassing other elements as well.
[0027] It should also be noted that, in the description of this disclosure, unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" 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 direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this disclosure depending on the specific circumstances. When a particular device is described as being located between a first device and a second device, an intermediary device may or may not be present between the particular device and the first or second device.
[0028] All terms used in this disclosure have the same meaning as understood by one of ordinary skill in the art to which this disclosure pertains, unless otherwise specifically defined. It should also be understood that terms defined in general dictionaries should be interpreted as having meanings consistent with their meanings in the context of the relevant art, and not as idealized or highly formalized, unless expressly defined herein.
[0029] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.
[0030] refer to Figures 1-5 As shown, this solution provides a core, wherein, along the radial direction (i.e., Figure 1 A multi-layer electrode assembly arranged sequentially in a left-right direction (in the image). The electrode assembly includes a negative electrode 3, a first separator 2, a positive electrode 4, and a second separator 5 arranged sequentially in a radially outward direction. The positive electrode 4 includes a positive current collector 42 and a positive electrode tab 43 connected to a first end of the positive current collector 42 in the axial direction. The negative electrode 3 includes a negative current collector 32 and a negative electrode tab 33 connected to a second end of the negative current collector 32 in the axial direction. In the N+1th layer of the electrode assembly in the radially outward direction, the height h of the positive electrode tab 43 in the axial direction is... N Satisfy: h N+1 <(2t1+t2+t3)×N+t1+t3, the height H of the negative electrode tab 33 along the axial direction is... N Satisfy: H N+1 <(2t1+t2+t3)×N, where t1 is the thickness of the first separator 2 or the thickness of the second separator 5, t2 is the thickness of the positive electrode 4, t3 is the thickness of the negative electrode 3, and N is a positive integer.
[0031] By setting the dimensional relationship between the thickness of the first or second diaphragm, the thickness of the positive electrode plate and the thickness of the negative electrode plate, and the height of the positive or negative electrode tab, the electrode tab is prevented from being flattened and covering the central hole, the electrode tab occupies less space in the axial direction of the cylinder, facilitates the welding of the current collector, avoids incomplete welding, and improves welding reliability.
[0032] Here, the axial direction refers to the axial direction of the core, and the radial direction also refers to the radial direction of the core. The first end of the positive current collector 42 in the axial direction refers to one end of the core, and the second end of the negative current collector 32 in the axial direction refers to the other end of the core.
[0033] The core includes a multi-layer electrode assembly arranged radially. Each electrode assembly is the smallest structural unit, including a negative electrode 3, a first diaphragm 2, a positive electrode 4, and a second diaphragm 5 arranged radially outward. The first diaphragm 2 and the second diaphragm 5 can have the same structure.
[0034] The positive electrode 4 may include a positive current collector 42, a positive active layer 41 disposed on both sides of the positive current collector 42, and a positive tab 43 connected to one end of the positive current collector 42. Similarly, the negative electrode 3 may include a negative current collector 32, a negative active layer 31 disposed on both sides of the negative current collector 32, and a negative tab 33 connected to one end of the negative current collector 32. That is, the positive tab 43 and the negative tab 33 are located at opposite ends of the winding core. The positive current collector 42 may be made of aluminum foil or the like, and the negative current collector 32 may be made of copper foil or the like.
[0035] The thickness of the positive electrode 4 refers to the total thickness of the positive current collector 42 and the two positive active layers 41, i.e., the maximum thickness. The thickness of the negative electrode 3 refers to the total thickness of the negative current collector 32 and the two negative active layers 31, i.e., the maximum thickness. The thickness of the first separator 2 and the thickness of the second separator 5 are the same, both being t1.
[0036] In some embodiments, the positive electrode tab 43 is bent toward the center hole 1 of the core relative to the positive electrode current collector 42, and is perpendicular or approximately perpendicular to the axial direction; similarly, the negative electrode tab 33 is bent toward the center hole 1 of the core relative to the negative electrode current collector 32, and is perpendicular or approximately perpendicular to the axial direction.
[0037] The height of the positive electrode tab 43 is the radial dimension of the core after the positive electrode tab 43 is bent and flattened, or the axial dimension of the core when the positive electrode tab 43 is coplanar with the positive current collector 42 (without being bent and flattened). N Satisfy: h N+1<(2t1+t2+t3)×N+t1+t3, similarly, the height of the negative electrode lug 33 is the radial dimension along the core after the negative electrode lug 33 is bent and flattened, or it is the axial dimension of the negative electrode lug 33 when it is coplanar with the negative electrode current collector 32 (the negative electrode lug 33 is not bent and flattened), H N Satisfy: H N+1 <(2t1+t2+t3)×N.
[0038] For example, when N=1, the height of the positive electrode tab 43 of the second layer is less than 2t1+t2+t3+t1+t3, where 2t1+t2+t3 is the overall thickness of the first layer electrode assembly, and t1+t3 is the thickness of the first diaphragm 2 and the negative electrode 3 in the second layer electrode assembly. After the positive electrode tab 43 of the second layer is bent toward the center hole of the core, the positive electrode tab 43 will not extend to the center hole 1. Similarly, when N=1, the height of the negative electrode tab 33 of the second layer is less than 2t1+t2+t3, where 2t1+t2+t3 is the overall thickness of the first layer electrode assembly. After the negative electrode tab 33 of the second layer is bent toward the center hole of the core, the negative electrode tab 33 will not extend to the center hole 1.
[0039] As can be seen, with the increase of N, i.e., with the increase of the number of layers, the upper limit of the height of the outer tab also increases, to ensure that the outer tab can at least partially fit with the inner tab after bending. In other words, for electrode assemblies with different layers, the height of the tabs is not exactly the same; the height of the outer tabs is relatively larger, while the height of the inner tabs is relatively smaller. This reduces the overall size of all tabs, thus reducing the axial space occupied by the tabs, facilitating the welding of the current collector, avoiding cold solder joints, and improving welding reliability.
[0040] In some embodiments, the height of the positive electrode tab 43 satisfies: h N <h N+1 <h N +2t1+t3, and 2t1+t3 <h N+1 For the positive electrode tab 43, the height of the (N+1)th layer is greater than the height of the Nth layer, and the difference between the height of the (N+1)th layer and the height of the Nth layer is less than the sum of the thicknesses of the negative electrode 3 and the two separators (i.e., the sum of the thicknesses of the structures between two adjacent positive electrode tabs 4). Furthermore, 2t1+t3 <h N+1 That is, the height of any positive electrode tab 43 is greater than the sum of the thicknesses of the negative electrode sheet 3 and the two separators. With the above settings, when the positive electrode tab is flattened, the positive electrode tab in the (N+1)th layer is exactly superimposed on the positive electrode tab in the Nth layer, but will not completely cover the positive electrode tab in the Nth layer. This reduces the occupancy of the positive electrode tab on the axial space of the cylinder, facilitates the welding of the current collector, avoids incomplete welding, and improves welding reliability.
[0041] In some embodiments, the height of the negative electrode tab 33 satisfies: H N <H N+1 <H N +2t1+t2, and 2t1+t2 <H N+1 For the negative electrode tab 33, the height of the (N+1)th layer is greater than the height of the Nth layer, and the difference between the height of the (N+1)th layer and the height of the Nth layer is less than the sum of the thicknesses of the positive electrode 4 and the two separators (i.e., the sum of the thicknesses of the structures between two adjacent negative electrode tabs 3). Furthermore, 2t1+t3 <h N+1 That is, the height of any negative electrode tab 33 is greater than the sum of the thicknesses of the positive electrode plate 4 and the two separators. With the above settings, when the negative electrode tab is flattened, the negative electrode tab in the (N+1)th layer is exactly superimposed on the negative electrode tab in the Nth layer, but will not completely cover the negative electrode tab in the Nth layer. This reduces the occupancy of the negative electrode tab on the axial space of the cylinder, facilitates the welding of the current collector, avoids incomplete welding, and improves welding reliability.
[0042] The shape of the electrode lug can be various, such as rectangle, square, parallelogram, isosceles trapezoid, etc. In addition, the width of the electrode lug can be a fixed value or the width can increase with the increase of the height of the electrode lug.
[0043] In some embodiments, multiple electrode assemblies are sequentially connected to form a wound structure. The portion of each electrode assembly near the center hole 1 of the core is designated as a first electrodeless tab section. In this first electrodeless tab section, the positive electrode 4 does not have a positive tab 43, and the negative electrode 3 does not have a negative tab 33. Multiple electrode assemblies can be integrally connected; in other words, the core is formed by winding a single electrode assembly into a multi-layered structure stacked from the center outwards. Each layer includes the aforementioned negative electrode 3, first diaphragm 2, positive electrode 4, and second diaphragm 5. The absence of positive and negative tabs 43 near the center hole 1, i.e., the innermost layer or multiple layers of electrode assemblies without positive and negative tabs 43, reduces the number of die-cutting operations, facilitates flattening, improves flatness, and prevents the positive and negative tabs 43 from obscuring the center hole 1.
[0044] In some embodiments, the length of the first electrodeless lug segment is 200-300 mm. The length of the first electrodeless lug segment refers to the length of the electrode assembly before winding, and it can be adjusted according to the overall size of the winding core.
[0045] In some embodiments, multiple electrode assemblies are sequentially connected to form a wound structure. The outermost portion of the electrode assembly located in the core is designated as a second electrodeless tab section. In this second electrodeless tab section, the positive electrode 4 does not have a positive tab 43, and the negative electrode 3 does not have a negative tab 33. Specifically, the portion of the electrode assembly near its outer periphery does not have positive and negative tabs 43, meaning the outermost layer or multiple layers of the electrode assembly do not have positive and negative tabs 43. This reduces the number of die-cutting operations for the tabs, facilitates flattening, and improves flatness. Alternatively, the multiple electrode assemblies can be integrally connected, i.e., a core is formed by winding a single electrode assembly.
[0046] In some embodiments, the length of the second tabless section is 200-300 mm. The length of the second tabless section refers to the length of the electrode assembly before winding, and it can be adjusted according to the overall size of the cylindrical cell.
[0047] In addition, in some embodiments, there may be a gap between adjacent positive tabs 43, for example, the gap may be 0.2-1.5mm; in other embodiments, they may be tightly attached together without a gap; furthermore, in some embodiments, the height of the positive tab 43 may be 2mm-6mm, and the width of the positive tab 43 may be 2-8mm.
[0048] In some embodiments, there may be a gap between adjacent negative electrode tabs 33, for example, the gap may be 0.2-1.5mm; in other embodiments, they may be tightly attached together without a gap; further, in some embodiments, the height of the negative electrode tab 33 may be 2mm-6mm, and the width of the negative electrode tab 33 may be 2-8mm.
[0049] In some embodiments, multiple electrode assemblies are sequentially connected to form a wound structure, with the positive electrode tab 43 and / or the negative electrode tab 33 inclined towards the winding direction of the electrode assembly. Multiple electrode assemblies are sequentially connected and formed by winding, where the winding direction refers to the direction from the starting end to the ending end of the winding. Before winding, the positive electrode tab 43 may be coplanar with the positive current collector 42, and the positive electrode tab 43 is inclined relative to the positive current collector 42 towards the winding direction, or in other words, towards the ending end. After winding, the positive electrode tab 43 is bent, and due to the tilt angle, i.e. Figure 5 As shown in 'a', this bending operation is also easier to achieve. After bending, the positive electrode tab 43 and the tangent at its location (the tangent at the arc-shaped edge of the positive electrode current collector 42, the direction of which is the winding direction in the winding state) also have an inclination angle, which is the same as the inclination angle before bending. The negative electrode tab 33 is in a similar situation, and will not be explained again here.
[0050] In some embodiments, the angle between the positive electrode tab 43 and / or the negative electrode tab 33 and the winding direction is 30-80°. For example, this angle can be 30°, 40°, 50°, 60°, 70°, 80°, etc. This structural design facilitates flattening, reduces the pressure required for flattening, and thus avoids excessive roller pressure that could lead to electrode deformation and active material shedding.
[0051] The core can be formed by winding a structure consisting of a positive electrode 4, a negative electrode 3, a first separator 2, and a second separator 5. At the beginning of the winding, the length of the negative electrode 3 is longer than that of the positive electrode 4, and at least one of the first separator 2 and the second separator 5 is longer than that of the negative electrode 3. During winding, the separator is first wound at least one turn to form a cylindrical shape. Then, the separator and the negative electrode 3 are wound into a cylindrical shape again. Then, the positive electrode 4, the first separator 2, the negative electrode 3, and the second separator 5 are wound simultaneously. Therefore, in the final structure, in the radially outward direction, the sequence is separator (at least one of the first separator 2 and the second separator 5), negative electrode 3, first separator 2, positive electrode 4, second separator 5, negative electrode 3... This ensures that the innermost ring is a separator, and that the negative electrode 3 exists on both the inner and outer sides of the positive electrode 3, thus avoiding or reducing lithium plating.
[0052] On the other hand, this disclosure also provides a battery cell, wherein the battery cell includes a housing and a winding core as described above, the winding core being disposed within the housing. The electrolyte in the battery cell can be a solid electrolyte (forming an all-solid-state battery), a solid-liquid hybrid electrolyte (forming a semi-solid-state battery), or a liquid electrolyte.
[0053] Furthermore, this disclosure also provides an electrical device, including the battery cell described in the above scheme. The electrical device may specifically be a battery pack, energy storage device, new energy vehicle, etc., and is not specifically limited thereto.
[0054] The embodiments of this disclosure have now been described in detail. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.
[0055] While specific embodiments of this disclosure have been described in detail by way of examples, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments or equivalent substitutions can be made to some technical features without departing from the scope and spirit of this disclosure. In particular, as long as there is no structural conflict, the technical features mentioned in the various embodiments can be combined in any manner.
Claims
1. A core, characterized in that The electrode core comprises a plurality of electrode piece assemblies arranged in sequence along a radial direction, each of the electrode piece assemblies comprises a negative electrode piece (3), a first separator (2), a positive electrode piece (4) and a second separator (5) arranged in sequence along a radial outward direction, the positive electrode piece (4) comprises a positive electrode current collector (42) and a positive electrode tab (43) connected to a first end of the positive electrode current collector (42) in an axial direction, and the negative electrode piece (3) comprises a negative electrode current collector (32) and a negative electrode tab (33) connected to a second end of the negative electrode current collector (32) in the axial direction. wherein, in the N+1th layer in the radially outward direction, the height h of the positive tab (43) N satisfies: h N+1 <(2t1+t2+t3)×N+t1+t3; and / or, the height H of the negative tab (33) N satisfies: H N+1 <(2t1+t2+t3)×N, wherein t1 is the thickness of the first separator (2) or the thickness of the second separator (5), t2 is the thickness of the positive tab (4), t3 is the thickness of the negative tab (3), and N is a positive integer.
2. The core of claim 1, wherein The height of the positive electrode tab (43) satisfies: h N <h N+1 <h N + 2ti + t3, and 2ti + t3 < h N+1 .
3. The core of claim 1, wherein The height of the negative tab (33) satisfies: H N <H N+1 <H N + 2ti + t2, and 2ti + t2 < H N+1 .
4. The core of claim 1, wherein The plurality of electrode piece assemblies are connected in sequence and form a winding structure, a part of the electrode piece assembly close to a central hole of the winding core is arranged as a first tab-free section, in the first tab-free section, the positive electrode piece (4) is not provided with the positive electrode tab (43), and / or the negative electrode piece (3) is not provided with the negative electrode tab (33).
5. The core of claim 4, wherein The length of the first tab-free section is 200-300 mm.
6. The core of claim 1, wherein The plurality of electrode piece assemblies are connected in sequence and form a winding structure, a part of the electrode piece assembly located at an outermost periphery of the winding core is arranged as a second tab-free section, in the second tab-free section, the positive electrode piece (4) is not provided with the positive electrode tab (43), and / or the negative electrode piece (3) is not provided with the negative electrode tab (33).
7. The core of claim 6, wherein The length of the second tab-free section is 200-300 mm.
8. The core of claim 1, wherein The plurality of electrode piece assemblies are connected in sequence and form a winding structure, the positive electrode tab (43) and / or the negative electrode tab (33) is inclined to a winding direction of the electrode piece assembly.
9. The core of claim 8, wherein The included angle between the positive electrode tab (43) and / or the negative electrode tab (33) and the winding direction is 30-80°.
10. An electric cell characterized by The battery cell comprises a shell and the winding core according to any one of claims 1-9, and the winding core is arranged in the shell.
11. An electrical device, characterized by The battery cell according to claim 10 is provided.