Pole piece assembly, Pole piece assembly scoring method, Battery cell, Battery pack, and Electric device

Abstract

This application discloses an electrode assembly, a method for scoring the electrode assembly, a battery cell, a battery pack, and an electrical device, belonging to the field of battery technology. By setting at least one first scoring area and a first non-scoring area on the first electrode, and setting at least one second scoring area and a second non-scoring area on the second electrode, and along the thickness direction of the electrode assembly, at least a portion of the at least one first scoring area and the at least one second scoring area are offset from each other in the same plane. That is, the first electrode and the second electrode are scored in a targeted manner to form a first scoring area and a second scoring area with different scoring regions. This helps to reduce the difference in the wetting performance of the first electrode and the second electrode to the electrolyte caused by different positions of the electrode in the manufacturing process, thereby making the wetting performance of the first electrode and the second electrode consistent.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to an electrode assembly, a method for scoring the electrode assembly, a battery cell, a battery pack, and an electrical device. Background Technology

[0002] In related technologies, with the continuous iteration of manufacturing processes in the lithium battery industry, the consistency requirements for each electrode in the manufacturing process of the electrode assembly, one of the core components of a battery cell, are also constantly increasing. Due to differences in manufacturing processes, multiple electrodes in an electrode assembly can exhibit different wetting effects under the same wetting conditions, leading to poor consistency in the electrical performance of different electrode assemblies in different battery cells. The electrical performance of a battery cell includes current density, electrode compaction rate, electrode NP ratio (N stands for Negative electrode, P stands for Positive electrode; the full name of the electrode NP ratio is the ratio of negative to positive electrode surface capacity), or electrode expansion force. Summary of the Invention

[0003] This application provides an electrode assembly, a method for scoring the electrode assembly, a battery cell, a battery pack, and an electrical device to at least partially solve the above-mentioned technical problems.

[0004] To achieve the above objectives, according to a first aspect of this application, an electrode assembly is provided, the electrode assembly being used in the same battery cell, the electrode assembly comprising: a plurality of electrodes, the plurality of electrodes including a first electrode and a second electrode, wherein the first electrode and the second electrode have the same polarity or opposite polarity; wherein the first electrode includes at least a first notched region and a first non-notched region, the second electrode includes at least a second notched region and a second non-notched region, and along the thickness direction of the electrode assembly, at least a portion of at least one of the first notched regions is offset from the orthographic projection of at least one of the second notched regions in the same plane.

[0005] In the electrode assembly of this application embodiment, at least one first etched area and one first non-etched area are provided on the first electrode, and at least one second etched area and one second non-etched area are provided on the second electrode. The at least one first etched area and the at least one second etched area are offset from each other in the orthographic projection of the same plane along the thickness direction of the electrode assembly. That is, the first electrode and the second electrode are etched in a targeted manner to form a first etched area and a second etched area with different etched areas. This helps to reduce the difference in the wetting performance of the first electrode and the second electrode in the electrolyte caused by different positions of the electrode in the manufacturing process. This makes the wetting performance of the first electrode and the second electrode consistent, and makes the electrical performance of different electrode assemblies formed by multiple electrode combinations tend to be consistent, thereby improving the consistency of the electrical performance of different battery cells.

[0006] Optionally, both the first electrode and the second electrode include a current collector and an active layer, the active layer being disposed on at least one side of the current collector, and both the first and second notched areas being located within the active layer.

[0007] The difference in wetting performance between the first and second electrodes is usually caused by the local thickness difference of the active layer of the first or second electrode. By scoring the active layer, the inconsistency in the wetting performance of the first and second electrodes can be effectively improved.

[0008] Optionally, the first electrode includes m first notched regions, and the second electrode includes n second notched regions, where m is greater than n or m is less than n.

[0009] Optionally, the thickness data of the active layer of the first electrode is arranged in a wavy pattern along the length or width direction of the first electrode, and the first groove area includes at least one groove disposed in the active layer, wherein at least one of the depth, length and width of the groove varies with the thickness of the active layer.

[0010] And / or, the thickness layer of the active layer of the second electrode is configured in a wavy pattern along the length or width direction of the second electrode, and the first etched area includes at least one groove disposed in the active layer, wherein at least one of the depth, length and width of the groove varies with the thickness of the active layer.

[0011] Optionally, the depth of the groove increases as the thickness of the active layer increases, and the depth of the groove decreases as the thickness of the active layer decreases.

[0012] Optionally, the width of the first electrode and the width of the second electrode vary along the length direction of the electrode assembly; and / or, the length of the first electrode and the length of the second electrode vary along the width direction of the electrode assembly.

[0013] Optionally, a tab is provided on one side of the first electrode, and the first etched area is located closer to the tab than the first non-etched area; and / or, a tab is provided on one side of the second electrode, and the second etched area is located closer to the tab than the second non-etched area.

[0014] Optionally, a tab is provided on one side of the first electrode, and the first etched area is disposed away from the tab relative to the first non-etched area; and / or, a tab is provided on one side of the second electrode, and the second etched area is disposed away from the tab relative to the second non-etched area.

[0015] Optionally, the first non-marked area is configured to surround the first marked area, and the first marked area is located in the central region of the first electrode; and / or, the second non-marked area is configured to surround the second marked area, and the second marked area is located in the central region of the second electrode.

[0016] Optionally, both the first electrode and the second electrode include a main body and an extension, the length of the extension being less than the length of the main body, and an electrode tab being provided on one side of the main body; at least a portion of the first scoring area and / or the second scoring area is located on the main body.

[0017] Optionally, the first scoring area and / or the second scoring area includes a first portion and a second portion connected together, the first portion being located on the main body and the second portion being located on the extension.

[0018] Optionally, both the first electrode and the second electrode include a main body and an extension, the length of the extension being less than the length of the main body, and an electrode tab being provided on one side of the main body; at least a portion of the first scoring area and / or the second scoring area is located on the extension.

[0019] Optionally, both the first electrode and the second electrode include a main body and an extension, the length of the extension being less than the length of the main body, and an electrode tab being provided on one side of the extension; at least a portion of the first scoring area and / or the second scoring area is located on the extension.

[0020] Optionally, the ratio of the surface area of ​​the first or second notched area to the surface area of ​​the extension is 0.3 to 1.2.

[0021] According to a second aspect of this application, a scoring method is provided for the above-described electrode assembly, the scoring method comprising: Obtain the thickness data of the active layer at different locations of the first electrode; The first etched area is determined based on the difference in the thickness data of the active layer at different locations of the first electrode. Obtain the thickness data of the active layer at different locations of the second electrode; The second notch region is determined based on the difference in the thickness data of the active layer at different locations of the second electrode. In this configuration, along the thickness direction of the electrode assembly, the first grooved area and the second grooved area are offset from each other in orthographic projection on the same plane.

[0022] Optionally, the first electrode includes a first region and a second region, and determining the first notched region based on the difference in the thickness data of the active layer at different locations of the first electrode includes: When the thickness of the active layer in the first region of the first electrode is greater than the thickness of the active layer in the second region, the first region is defined as the first etched region, and the second region is defined as the first non-etched region. And / or, the second electrode includes a first region and a second region, and the determination of the second notched region based on the difference in thickness data of the active layer at different locations of the second electrode includes: When the thickness of the active layer in the first region of the second electrode is greater than the thickness of the active layer in the second region, the first region is determined as the second etched region, and the second region is determined as the second non-etched region.

[0023] Optionally, the first electrode further includes a third region, and determining the first notched region based on the difference in thickness data of the active layer at different locations of the first electrode includes: When the thickness of the active layer in the first region and the thickness of the active layer in the third region of the first electrode are both greater than the thickness of the active layer in the second region, the first region and the third region are determined as two first etched regions, and the second region is determined as a first non-etched region. And / or, the second electrode further includes a third region, wherein determining the second notched region based on the difference in thickness data of the active layer at different locations of the second electrode includes: When the thickness of the active layer in the first region and the thickness of the active layer in the third region of the second electrode are both greater than the thickness of the active layer in the second region, the first region and the third region are determined as two second etched regions, and the second region is determined as a second non-etched region.

[0024] According to a third aspect of this application, a battery cell is also provided, comprising: The electrode assembly as described above; The housing contains the electrode assembly.

[0025] Optionally, the battery cell may include a cylindrical battery, a square battery, a blade battery, or an irregularly shaped battery.

[0026] According to a fourth aspect of this application, a battery pack is also provided, the battery pack comprising a plurality of battery cells as described above.

[0027] According to a fifth aspect of this application, an electrical appliance is also provided, the electrical appliance comprising the battery pack described above.

[0028] In the electrode assembly of this application embodiment, at least one first etched area and one first non-etched area are provided on the first electrode, and at least one second etched area and one second non-etched area are provided on the second electrode. The at least one first etched area and the at least one second etched area are offset from each other in the orthographic projection of the same plane along the thickness direction of the electrode assembly. That is, the first electrode and the second electrode are etched in a targeted manner to form a first etched area and a second etched area with different etched areas. This helps to reduce the difference in the wetting performance of the first electrode and the second electrode in the electrolyte caused by different positions of the electrode in the manufacturing process. This makes the wetting performance of the first electrode and the second electrode consistent, and makes the electrical performance of different electrode assemblies formed by multiple electrode combinations tend to be consistent, thereby improving the consistency of the electrical performance of different battery cells.

[0029] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0032] Figure 1 This is a schematic diagram of the planar structure of the first and second pole pieces provided in an exemplary embodiment of this disclosure; Figure 2 This is a schematic diagram of the planar structure of the first and second electrodes provided in yet another exemplary embodiment of this disclosure; Figure 3 This is a schematic cross-sectional view of the electrode structure provided in an exemplary embodiment of this disclosure; Figure 4 This is a three-dimensional structural diagram of the active layer of the electrode provided in an exemplary embodiment of this disclosure; Figure 5a This is a schematic diagram of the thickness variation of the active layer of the electrode provided in an exemplary embodiment of this disclosure; Figure 5b Based on Figure 5a A schematic diagram showing the depth variation of the grooves within the etched area of ​​the provided active layer; Figure 6aThis is a schematic diagram of the thickness variation of the active layer of the electrode provided in another exemplary embodiment of this disclosure; Figure 6b Based on Figure 6a A schematic diagram showing the depth variation of the grooves within the etched area of ​​the provided active layer; Figure 7a This is a planar structural diagram of a conventional electrode in an upright position provided in an exemplary embodiment of this disclosure; Figure 7b This is a planar structural diagram of a conventional electrode in an inverted position provided in an exemplary embodiment of this disclosure; Figure 7c This is a planar structural diagram of a conventional electrode in a horizontally placed position provided in an exemplary embodiment of this disclosure; Figure 8a This is a planar structural diagram of an irregularly shaped electrode sheet placed upright, provided in an exemplary embodiment of this disclosure; Figure 8b This is a planar structural diagram of an irregularly shaped electrode sheet in an inverted position, provided in an exemplary embodiment of this disclosure; Figure 9a This is a planar structural diagram of another irregularly shaped electrode in an upright position, provided in an exemplary embodiment of this disclosure; Figure 9b This is a planar structural diagram of another irregularly shaped electrode in an upright position, provided in yet another exemplary embodiment of this disclosure; Figure 9c This is a planar structural diagram of another irregularly shaped electrode sheet in a horizontally placed position, provided in an exemplary embodiment of this disclosure; Figure 9d This is a planar structural diagram of another irregularly shaped electrode in an inverted position, provided in an exemplary embodiment of this disclosure.

[0033] Explanation of reference numerals in the attached figures: 10. Electrode; 100. First electrode; 101. First notched area; 102. First non-notched area; 200, Second electrode; 201, Second notched area; 202, Second non-notched area; 300. Current collector; 400, Active layer; 410, First active layer; 420, Second active layer; 500, Groove; 600, Electrode; 710. Main body; 720. Extension; 810. Part One; 820. Part Two. Detailed Implementation

[0034] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0035] In related technologies, with the continuous iteration of manufacturing processes in the lithium battery industry, electrode components, as one of the core components of a battery cell, face increasingly stringent requirements for the consistency of each electrode sheet in their manufacturing process. Due to differences in manufacturing processes, multiple electrodes within an electrode component can exhibit varying wetting effects under the same wetting conditions, leading to poor consistency in the electrical performance of electrode components from different battery cells. The electrical performance of a battery cell includes current density, electrode compaction rate, electrode NP ratio, and electrode expansion force. The intrinsic properties of different battery cells are manifested as follows: First, the expansion stress of the battery cell is concentrated on its large surface area. Second, under high-rate conditions, lithium plating is prone to occur at the root of the electrode tabs. Third, under the same wetting conditions, when the battery cell has special design proportions in different directions (length, width, height), such as in blade batteries, the wetting difficulty of the electrode component increases dramatically.

[0036] To address the above technical issues, conventional process methods involve expanding the process window or material properties to meet the design goals of individual battery cells. However, different factories adapting to different battery cells have different priorities during the planning process. As a result, this approach can lead to bottlenecks in the production process of other battery cells, making it difficult for the factory to fully utilize its capacity.

[0037] Embodiments of this application provide an electrical device, which may be a mobile phone, laptop computer, electric vehicle, electric car, electric aircraft, electric ship, electric toy, or power tool. The electrical device includes one or more individual battery cells or battery packs for providing electrical power.

[0038] Embodiments of this application provide a battery pack, which can be an energy storage device, including an energy storage container, an energy storage cabinet, etc. The battery pack can also be a power battery pack, which can be used in mobile phones, laptops, electric vehicles, electric cars, electric aircraft, electric ships, electric toys, and power tools.

[0039] The battery pack includes a housing and an assembly of one or more individual battery cells, with the assembly of one or more individual battery cells disposed within the housing.

[0040] A battery cell assembly is typically formed by arranging multiple battery cells. As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form an independent module.

[0041] As an example, a battery cell may include a lithium-ion secondary battery cell, a lithium-ion primary battery cell, a lithium-sulfur battery cell, a sodium-lithium-ion battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, etc.

[0042] The enclosure can be part of the chassis structure of an electric vehicle. For example, a portion of the enclosure can be at least part of the vehicle's floor, or a portion of the enclosure can be at least part of the vehicle's crossbeams and longitudinal beams.

[0043] This application provides a battery cell in its embodiments. The battery cell can be a cylindrical battery cell, a prismatic battery cell, or an irregularly shaped battery cell. Prismatic battery cells include prismatic battery cells, blade-shaped battery cells, and multi-prismatic battery cells. Irregularly shaped battery cells are configured with a regular or irregular polygonal structure. The battery cell can be a lithium battery, a sodium battery, a semi-solid-state battery, or a solid-state battery.

[0044] A single battery cell includes a casing, electrode assembly, and electrolyte.

[0045] The casing is designed to encapsulate components such as electrode assemblies and electrolytes. A pressure relief valve is provided on the casing to release the internal pressure of the individual battery cells.

[0046] The electrode assembly includes multiple positive electrode plates, multiple negative electrode plates, and multiple separators. During the charging and discharging process of a single battery cell, active ions repeatedly insert and extract between the positive and negative electrode plates. Each separator is positioned between each positive and negative electrode plate, serving to prevent short circuits between the positive and negative electrodes while allowing active ions to pass through.

[0047] The positive electrode includes a positive current collector and a positive active material layer disposed on at least one surface of the positive current collector. The negative electrode includes a negative current collector and a negative active material layer disposed on at least one surface of the negative current collector.

[0048] In some embodiments, the electrode assembly is a wound structure, in which a positive electrode, a separator, and a negative electrode are alternately arranged and wound into a wound structure. Alternatively, the electrode assembly is a stacked structure, in which multiple positive electrodes, multiple separators, and multiple negative electrodes are alternately stacked.

[0049] In some embodiments provided in this application, an electrode assembly for the same battery cell is provided. The electrode assembly includes a plurality of electrodes 10. As an example, the plurality of electrodes 10 are configured as a stacked structure and are stacked along the thickness direction z of the electrode assembly.

[0050] like Figures 1 to 3 As shown, the plurality of electrode plates 10 include a plurality of first electrode plates 100 and a plurality of second electrode plates 200, and the plurality of first electrode plates 100 or the plurality of second electrode plates 200 include at least one of a plurality of positive electrode plates and a plurality of negative electrode plates. Taking a laminated electrode assembly as an example, the first electrode plate 100 and the second electrode plate 200 can be positive electrode plates located in different layers, or the first electrode plate 100 and the second electrode plate 200 can be negative electrode plates located in different layers, or the first electrode plate 100 and the second electrode plate 200 can be positive electrode plates and negative electrode plates located in different layers.

[0051] The first electrode 100 includes at least one first notched area 101 and a first non-notched area 102, and the second electrode 200 includes at least one second notched area 201 and a second non-notched area 202. Along the thickness direction z of the electrode assembly, at least a portion of the at least one first notched area 101 is offset from the orthographic projection of the at least one second notched area 201 on the same plane. That is, the position of the at least one first notched area 101 on the first electrode 100 is different from the position of the at least one second notched area 201 on the second electrode 200. As an example, such as... Figure 1 As shown, the first electrode 100 includes a first notched area 101, and the second electrode 200 includes a second notched area 201. The first notched area 101 is located in the upper region of the first electrode 100 and is disposed close to the tab 600, while the second notched area 201 is located in the central region of the second electrode 200. As another example, such as... Figure 2 As shown, the first electrode 100 includes three first notched areas 101, and the second electrode 200 includes two second notched areas 201. The orthographic projection of one of the first notched areas 101 of the first electrode 100 along the thickness direction z of the electrode assembly is located in the second non-notched area 202 of the second electrode 200. That is, the positions of the notched areas of the multiple electrodes in the electrode assembly are not fixed, and the notched areas are determined based on the molding structure of the electrode itself.

[0052] It should be noted that the electrode assembly of the same battery cell includes multiple electrodes 10. These electrodes 10 include a first electrode 100 and a second electrode 200 with different notched areas, as well as a third and fourth electrode with the same notched area, and a fifth electrode without a notched structure. Before the notched structures are applied, the first, second, third, and fourth electrodes have a lower wetting ability in the electrolyte compared to the fifth electrode. Furthermore, the wetting performance of the first and second electrodes 100 differs at the same location, while the wetting performance of the third and fourth electrodes at the same location is essentially the same. Therefore, regarding the first electrode 100 and the second electrode 200… 0. Targeted scoring is performed, wherein the position of the first scoring area 101 of the first electrode 100 is different from the position of the second scoring area 201 of the second electrode 200, and the scoring positions of the third and fourth electrodes are the same, so that the wetting ability of the first electrode 100, the second electrode 200, the third electrode, the fourth electrode and the fifth electrode is basically the same. That is, it is difficult to form electrolyte wetting blind areas in multiple electrodes in the same electrode assembly, which is conducive to improving the consistency of the electrical performance of the battery cell.

[0053] Understandably, due to the differences in manufacturing processes, different regions of the first electrode 100 and the second electrode 200 will have different wetting properties with the electrolyte. The difference in the wetting properties of a single electrode will lead to differences in the current density, electrode NP ratio, electrode expansion force, and other properties of different electrode assemblies formed by combining multiple electrodes. In this application, along the thickness direction z of the electrode assembly, at least one first grooved area 101 on the first electrode 100 and the second grooved area 201 of the second electrode 200 are at least partially offset on the same plane. That is, by addressing the differences in the manufacturing process of the first electrode 100 and the second electrode 200, targeted grooves are made on the first electrode 100 and the second electrode 200 to form first grooved areas 101 and second grooved areas 201 with different grooved areas. This makes the wetting performance of the first electrode 100 consistent with that of the second electrode 200, thereby making the electrical performance of different electrode assemblies formed by multiple electrode combinations tend to be consistent, thereby improving the consistency of the battery cells.

[0054] For example, when the wetting performance of the edge of the first electrode 100 is poor, a first notch area 101 is provided on the edge of the first electrode 100; and when the wetting performance of the root of the tab of the second electrode 200 is poor, a second notch area 201 is provided at the root of the tab of the second electrode 200, thereby ensuring that the wetting performance of each position of the first electrode 100 and the second electrode 200 is consistent. Similarly, when the wetting performance of the central region of the first electrode 100 is poor, a first notch area 101 is provided in the central region of the first electrode 100; and when the wetting performance of the region near the tab of the second electrode 200 is poor, a second notch area 201 is provided in the region near the tab of the second electrode 200, to ensure that the wetting performance of each position of the first electrode 100 and the second electrode 200 is consistent.

[0055] Furthermore, in related technologies, the first and second electrodes of multiple electrodes in the same battery cell are all scored in specific, identical areas to ensure that the scoring distribution areas of the first and second electrodes are completely identical. In this application, however, targeted scoring is performed on areas with poor local wetting performance on the first electrode 100 or the second electrode 200, while areas with good wetting performance are designated as non-scoring areas. This ensures that the wetting ability of the scoring and non-scoring areas to the electrolyte is consistent, thereby reducing the scoring processing area of ​​the electrode and thus reducing the large amount of dust generated during the scoring process.

[0056] In some embodiments, such as Figure 3 As shown, both the first electrode 100 and the second electrode 200 include a current collector 300 and an active layer 400, wherein the active layer 400 is disposed on at least one side of the current collector 300, and the first notched region 101 and the second notched region 201 are both located on the active layer 400. As an example, the first electrode 100 and the second electrode 200 include a current collector 300 disposed on both sides of the current collector 300, with a first active layer 410 and a second active layer 420, wherein the first notched region 101 of the first electrode 100 may be located on either the first active layer 410 or the second active layer 420. Alternatively, the first active layer 410 and the second active layer 420 of the first electrode 100 may both have a first notched region 101. Similarly, the second notched region 201 of the second electrode 200 may be located on either the first active layer 410 or the second active layer 420. Alternatively, the first active layer 410 and the second active layer 420 of the second electrode 200 may both have a second notched region 201.

[0057] The difference in wetting performance between the first electrode 100 and the second electrode 200 is usually due to the local thickness difference of the active layer 400 of the first electrode 100 or the second electrode 200. By scoring the active layer 400, the inconsistency in the wetting performance of the first electrode 100 and the second electrode 200 can be effectively improved.

[0058] In some embodiments, Figure 5a and Figure 6a As shown, the thickness data of the active layer 400 of the first electrode 100 is arranged in a wavy pattern along the length direction x or width direction y of the first electrode 100, such as... Figure 4 , Figure 5b and Figure 6b As shown, the first notched area 101 includes at least one groove 500 disposed on the active layer 400. At least one of the depth, length, and width of the groove 500 varies with the thickness of the active layer 400 of the first electrode 100. The wavy arrangement may include the thickness of the active layer 400 increasing and then decreasing along the length direction x or width direction y of the electrode in an alternating manner, where the magnitudes of the increase and decrease can be the same or different. The wavy arrangement may also include the thickness of the active layer 400 increasing, then remaining constant, and then decreasing along the length direction x or width direction y in an alternating manner, where the magnitudes of the increase and decrease can be the same or different.

[0059] For example, such as Figure 6a and Figure 6b As shown, the depth of the groove 500 located in the first notched region 101 increases as the thickness of the active layer 400 increases, and decreases as the thickness of the active layer 400 decreases. The first notched region 101 may include multiple grooves 500. The variation in the depth of the grooves 500 in the first notched region 101 with the thickness of the active layer 400 includes three cases: First, the thickness of the active layer 400 varies along the length x of the electrode, and the first notched region 101 includes multiple grooves 500 spaced apart along the length x of the electrode; the depth of the multiple grooves 500 varies with the thickness of the active layer 400. The second type involves the thickness of the active layer 400 varying along the width direction y of the electrode. The first notched region 101 includes multiple grooves 500 arranged along the length direction x of the electrode. The same groove 500 extends along the width direction y of the electrode, and the width of the same groove 500 varies along the width direction y of the electrode with the thickness of the active layer 400. The third type involves the thickness of the active layer 400 varying along both the length direction x and the width direction y of the electrode. The first notched region 101 includes multiple grooves 500 spaced apart along the length direction x of the electrode. The same groove 500 extends along the width direction y of the electrode. Along the length direction x of the electrode, the depth of the multiple grooves 500 varies with the thickness of the active layer 400, and along the width direction y of the electrode, the width of the same groove 500 varies with the thickness of the active layer 400.

[0060] Similarly, the thickness data of the active layer 400 of the second electrode 200 is arranged in a wavy pattern along the length direction x or width direction y of the second electrode 200. The second notched region 201 includes at least one groove 500 disposed on the active layer 400. At least one of the depth, length or width of the groove 500 increases as the thickness of the active layer 400 increases, and the depth of the groove 500 located in the second notched region 201 decreases as the thickness of the active layer 400 decreases.

[0061] Understandably, when a localized area of ​​the active layer 400 is thickened, the wetting performance of that localized area will be poor. Increasing the depth of the groove 500 in that localized area helps improve the wetting performance, thus ensuring consistent wetting performance across all areas of the active layer 400. Understandably, when the active layer 400 is coated on the current collector 300 of the first electrode 100 or the second electrode 200, fluctuations in process parameters can cause microscopic variations in the thickness of the active layer 400 at different locations. Adjusting the depth of the groove 500 based on these thickness variations can effectively eliminate the differences in wetting performance caused by these thickness fluctuations.

[0062] In some embodiments, such as Figure 2 As shown, the first electrode 100 includes a plurality of first notched regions 101, and the second electrode 200 includes one or more second notched regions 201, or the first electrode 100 includes one first notched region 101, and the second electrode 200 includes a plurality of second notched regions 201. Specifically, the first electrode 100 includes m first notched regions 101, and the second electrode 200 includes n second notched regions 201, where m is greater than n, or m is less than n, that is, m is not equal to n.

[0063] To address multiple differences at various locations on the first electrode 100, multiple first notch areas 101 can be provided on the first electrode 100. Similarly, to address one or more differences at various locations on the second electrode 200, one or more second notch areas 201 can be provided on the first electrode 100. For example, one first notch area 101 can be provided on the first electrode 100, and two or three second notch areas 201 can be provided on the second electrode 200. That is, for multiple electrodes in the same electrode assembly, the positions and number of notch areas are not fixed, thus ensuring consistent wetting performance of the first electrode 100 and the second electrode 200 after the notch process.

[0064] The applicant also discovered that when the electrode structures of individual battery cells are different, adjusting the marking positions of the first electrode 100 and the second electrode 200 in the electrode assembly can also help to ensure consistent wetting performance areas for different battery cells. For example, when a battery cell is placed upright, upside down, or horizontally, the marking positions on the first electrode 100 and the second electrode 200 need to be adjusted according to the placement of the battery cell to ensure that the wetting ability of each position of the first electrode 100 and the second electrode 200 to the electrolyte is more consistent.

[0065] In some embodiments, such as Figure 7a As shown, both the first electrode 100 and the second electrode 200 are conventional sheet-shaped electrodes. Each of the first electrode 100 and the second electrode 200 has a tab 600 on one side. When the battery cell is placed upright, the tab 600 on the first electrode 100 is located at the top of the first electrode 100, and the tab 600 on the second electrode 200 is located at the top of the second electrode 200. The first notched area 101 on the first electrode 100 is closer to the tab 600 than the first non-notched area 102, and the second notched area 201 on the second electrode 200 is closer to the tab 600 than the second non-notched area 202.

[0066] Understandably, when a battery cell is placed upright with the tabs of the electrode assembly facing upwards, the electrolyte level gradually decreases as the electrolyte inside the battery cell is consumed during the wetting process. If the electrolyte creepage height remains constant, this results in insufficient wetting at the top of the electrode, leading to a relatively high current density and increased susceptibility to lithium plating at the electrode tip. In this application, by providing a first notch region 101 at the top of the first electrode 100 (near the tab 600) and a second notch region 201 at the top of the second electrode 200 (near the tab 600), the electrolyte creepage height and the saturated electrolyte absorption of the electrode are effectively increased, thereby improving the overall consistency of the wetting effect of the battery cell.

[0067] In some embodiments, such as Figure 7b As shown, both the first electrode 100 and the second electrode 200 are conventional sheet-shaped electrodes. Each of the first electrode 100 and the second electrode 200 has a tab 600 on one side. When the battery cell is inverted, the tab 600 on the first electrode 100 is located at the bottom end of the first electrode 100, and the tab 600 on the second electrode 200 is located at the bottom end of the second electrode 200. The first notched area 101 on the first electrode 100 is positioned away from the tab 600 relative to the first non-notched area 102, and the second notched area 201 on the second electrode 200 is positioned away from the tab 600 relative to the second non-notched area 202.

[0068] Understandably, when a battery cell is placed upside down, with the tabs of the electrode assembly facing downwards, the electrolyte level gradually decreases as the electrolyte inside the battery cell is consumed during the wetting process. If the electrolyte creep height remains constant, this results in insufficient wetting at the top of the electrode, leading to a relatively high current density and increased susceptibility to lithium plating at the top. In this application, by providing a first notch region 101 at the top of the first electrode 100, away from the tab 600, and a second notch region 201 at the top of the second electrode 200, away from the tab 600, the electrolyte creep height and the saturated electrolyte absorption of the electrode are effectively increased, thereby improving the overall consistency of the wetting effect of the battery cell.

[0069] In some embodiments, such as Figure 7c As shown, both the first electrode 100 and the second electrode 200 are conventional sheet-shaped electrodes. Each of the first electrode 100 and the second electrode 200 has a tab 600 on one side. When the battery cell is placed horizontally, the tab 600 on the first electrode 100 is located on either the left or right side, and the tab 600 on the second electrode 200 is located on either the left or right side. The first notched area 101 on the first electrode 100 is closer to the top of the electrode than the first non-notched area 102, and the second notched area 201 on the second electrode 200 is closer to the top of the electrode than the second non-notched area 202.

[0070] Understandably, when a battery cell is placed horizontally, the tabs of the electrode assembly are located on the left or right side of the electrode. During the process of electrolyte wetting the electrode assembly, as the electrolyte inside the battery cell is consumed, the electrolyte level gradually decreases. Under the condition that the electrolyte creep height remains unchanged, this leads to insufficient wetting at the top of the electrode, resulting in a relatively high current density at the top of the electrode and making it prone to lithium plating. In this application, by providing a first notch region 101 at the top of the first electrode 100 and a second notch region 201 at the top of the second electrode 200, the electrolyte creep height and the saturated electrolyte absorption of the electrode can be effectively improved, thereby improving the consistency of the overall wetting effect of the battery cell.

[0071] In some embodiments, such as Figure 1 As shown, the first non-marked area 102 of the first electrode 100 is configured to surround the first marked area 101, and the first marked area 101 is located in the central region of the first electrode 100. The second non-marked area 202 of the second electrode 200 is configured to surround the second marked area 201, and the second marked area 201 is located in the central region of the second electrode 200.

[0072] Understandably, when a battery cell is placed upright and the electrode assembly inside the battery cell is configured as a stacked structure, due to the cohesive force of the electrode assembly inside the battery cell and the electrolyte concentrated at the bottom of the battery cell, the electrolyte cannot directly diffuse on the large surface of the battery cell due to the multi-layered stacked structure of the electrode assembly. The electrolyte wetting path is from the periphery to the center of the electrode assembly, which results in the wetting performance of the central area of ​​the electrode assembly being less than that of the surrounding areas, thus easily leading to black spots or lithium plating on the electrode assembly. In the embodiments of this application, by providing a first notch area 101 in the central area of ​​the first electrode 100, the wetting performance of the central area of ​​the first electrode 100 is improved, and by providing a second notch area 201 in the central area of ​​the second electrode 200, the wetting performance of the central area of ​​the second electrode 200 is improved, thereby avoiding the appearance of black spots or lithium adsorption in the central area of ​​the electrode assembly.

[0073] In some embodiments, the battery cell is configured as an irregularly shaped battery, and the corresponding electrode assembly is configured as an irregularly shaped electrode assembly, wherein both the first electrode 100 and the second electrode 200 of the electrode assembly are configured as irregularly shaped electrodes. Compared with conventional regular polygonal electrodes, the center of gravity of the irregularly shaped electrode with a non-regular polygonal structure will change accordingly, resulting in a significant difference in the wetting performance of the irregularly shaped electrode to the electrolyte compared with that of conventional electrodes.

[0074] As some examples, such as Figure 8a and Figure 8b As shown, the first electrode 100 and the second electrode 200 are configured as non-regular polygons. For example, the width of the first electrode 100 and the width of the second electrode 200 vary along the length direction x of the electrode assembly, or the length of the first electrode 100 and the length of the second electrode 200 vary along the width direction y of the electrode assembly. For example, the first electrode 100 and the second electrode 200 are configured as trapezoidal structures.

[0075] Compared to conventional regular polygonal electrode sheets, the center of gravity of non-regular polygonal electrode sheets changes accordingly. To improve the consistency of wetting performance among multiple electrode sheets in the electrode assembly, a first notched area 101 is provided in a localized area of ​​the first electrode sheet 100. The first electrode sheet 100 includes an upper region and a lower region distributed along its length direction x, and a left region and a right region distributed along its width direction y. The upper region is provided with an electrode tab 600. The first notched area 101 can be located in the upper region, lower region, left region, or right region of the first electrode sheet 100. The specific location of the first notched area 101 can be designed based on factors such as the thickness difference of different positions of the active layer 400 of the first electrode sheet 100, the center of gravity position of the first electrode sheet 100, and the placement state of the first electrode sheet 100.

[0076] Similarly, the second electrode 200 includes an upper region and a lower region along its length direction x, and a left region and a right region distributed along its width direction y. The upper region is provided with a tab 600. The second notched region 201 can be located in the upper region, lower region, left region, or right region of the second electrode 200. The specific location of the second notched region 201 can be designed based on factors such as the thickness difference of the active layer 400 of the second electrode 200, the center of gravity of the second electrode 200, and the placement state of the second electrode 200.

[0077] As examples, both the first electrode 100 and the second electrode 200 are configured as composite polygons, and the wetting paths of the composite polygon electrodes are non-uniformly distributed compared to conventional regular polygon electrodes.

[0078] As examples, both the first electrode 100 and the second electrode 200 include a main body 710 and an extension 720. Along the width direction y of either the first electrode 100 or the second electrode 200, the length of the extension 720 is less than the length of the main body 710. An electrode tab 600 is provided at one end of the main body 710 away from the extension 720, or on the right side of the extension 720 away from the main body 710. The wetting path changes at the connection between the extension 720 and the main body 710, resulting in differences in the wetting performance at various locations of the first electrode 100 and the second electrode 200.

[0079] Therefore, in this application, as Figure 9a As shown, when the battery cell is placed upright, the extensions 720 of the first electrode 100 and the second electrode 200 are both located at the bottom of the main body 710, the tab 600 is connected to the top of the main body 710, and the first grooved area 101 of the first electrode 100 is located in the left side region of the main body 710, or as shown... Figure 9b As shown, the first grooved area 101 of the first electrode 100 includes a first portion 810 and a second portion 820 connected together, wherein the first portion 810 is located in the left side region of the main body 710, and the second portion 820 is located in the left side region of the extension 720, with the first portion 810 connected to the second portion 820. Similarly, the second grooved area 201 of the second electrode 200 is located in the left side region of the main body 710, or the second grooved area 201 of the second electrode 200 includes a first portion 810 and a second portion 820 connected together, wherein the first portion 810 is located in the left side region of the main body 710, and the second portion 820 is located in the left side region of the extension 720, so that the wetting performance of each position of the first electrode 100 and the second electrode 200 is consistent.

[0080] In some embodiments, such as Figure 9dAs shown, when the battery cell is placed upside down, the extensions 720 of both the first electrode 100 and the second electrode 200 are located at the top of the main body 710, the tab 600 is connected to the bottom of the main body 710, and the first grooved area 101 of the first electrode 100 is located in the extension 720. Similarly, the second grooved area 201 of the second electrode 200 is located in the extension 720, so that the wetting performance of each position of the first electrode 100 and the second electrode 200 is consistent.

[0081] In some embodiments, such as Figure 9c As shown, when the battery cell is placed horizontally, the extensions 720 of the first electrode 100 and the second electrode 200 are both located at the top of the main body 710. The tab 600 is connected to one side of the extension 720. The first grooved area 101 of the first electrode 100 is located in the extension 720, and similarly, the second grooved area 201 of the second electrode 200 is located in the extension 720, so that the wetting performance of each position of the first electrode 100 and the second electrode 200 is consistent.

[0082] In some embodiments, when the battery cell is placed horizontally or upright, at least a portion of the first grooved region 101 of the first electrode 100 is located in the extension 720 of the first electrode 100, and at least a portion of the second grooved region 201 of the second electrode 200 is located in the extension 720 of the second electrode 200, wherein the ratio of the surface area of ​​the first grooved region 101 to the surface area of ​​the extension 720 of the first electrode 100 is 0.3 to 1.2.

[0083] Understandably, when the battery cell is placed upright, the first grooved area 101 on the first electrode 100 includes a first portion 810 on the main body 710 and a second portion 820 on the extension 720, wherein the first portion 810 is connected to the second portion 820. When the ratio of the surface area of ​​the second portion 820 on the extension 720 to the surface area of ​​the extension 720 is less than 0.3, that is, the connection area at the transition between the extension 720 and the main body 710 on the first electrode 100 is small, which leads to a poor wetting ability of the portion of the main body 710 of the first electrode 100 protruding to the left of the extension 720 to the main body 710 during the process of electrolyte flowing from the extension 720 to the main body 710. Similarly, the second grooved area 201 on the second electrode 200 includes a first portion 810 on the main body 710 and a second portion 820 on the extension 720, wherein the first portion 810 is connected to the second portion 820. When the ratio of the surface area of ​​the second portion 820 on the extension 720 to the surface area of ​​the extension 720 is less than 0.3, that is, the connection area at the transition between the extension 720 and the main body 710 on the second electrode 200 is small, which leads to poor wetting ability of the portion of the main body 710 of the second electrode 200 protruding to the left of the extension 720 to the electrolyte during the process of the electrolyte flowing from the extension 720 to the main body 710.

[0084] When the battery cell is placed horizontally, the first notched area 101 of the first electrode 100 is located in the extension 720, and the extension 720 of the first electrode 100 is connected to the top of the main body 710. The electrolyte flows from the main body 710 of the first electrode 100 to the extension 720. When the ratio of the surface area of ​​the first notched area 101 to the surface area of ​​the extension 720 is less than 0.3, the wetting performance of the extension 720 of the first electrode 100 will be poor. Similarly, the second notched area 201 of the second electrode 200 is located in the extension 720, and the extension 720 of the second electrode 200 is connected to the top of the main body 710. The electrolyte flows from the main body 710 of the second electrode 200 to the extension 720. When the ratio of the surface area of ​​the second notched area 201 to the surface area of ​​the extension 720 is less than 0.3, the wetting performance of the extension 720 of the second electrode 200 will be poor.

[0085] When the ratio of the surface area of ​​the first notched region 101 of the first electrode 100 to the surface area of ​​the extension 720 of the first electrode 100 is greater than 1.2, the first notched region 101 occupies a larger surface area of ​​the first electrode 100. While this improves the consistency of wetting performance at various locations of the first electrode 100, it also results in weaker structural strength of the active layer 400 of the first electrode 100 and affects the capacitance of the first electrode 100. Similarly, when the ratio of the surface area of ​​the second notched region 201 of the second electrode 200 to the surface area of ​​the extension 720 of the second electrode 200 is greater than 1.2, the second notched region 201 occupies a larger surface area of ​​the second electrode 200. While this improves the consistency of wetting performance at various locations of the second electrode 200, it also results in weaker structural strength of the active layer of the second electrode 200 and affects the capacitance of the second electrode 200.

[0086] In a specific embodiment, the ratio of the surface area of ​​the first grooved area 101 of the first electrode 100 to the surface area of ​​the extension 720 can be 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, or any value between any two of the above values, or a range between any two of the above values.

[0087] In embodiments of this application, a scoring method for the above-mentioned electrode assembly is also provided, the scoring method comprising: Obtain the thickness data of the active layer 400 of the first electrode 100; The first notched region 101 is determined based on the difference in thickness data of the active layer 400 at different positions of the first electrode 100; Obtain the thickness data of the active layer 400 of the second electrode 200; The second notch region 201 is determined based on the difference in thickness data at different locations of the active layer 400 of the second electrode 200; In particular, along the thickness direction z of the electrode assembly, the first notch area 101 and the second notch area 201 are offset in orthographic projection on the same plane.

[0088] The position of the first notched region 101 of the first electrode 100 is determined based on the difference in thickness data at different locations of the active layer 400 of the first electrode 100. This allows the first notched region 101 to balance the significant differences in wetting ability at various locations caused by the thickness differences between the first notched region 101 and the first non-notched region 102 of the active layer 400 of the first electrode 100. Similarly, the position of the second notched region 201 of the second electrode 200 is determined based on the difference in thickness data at different locations of the active layer 400 of the second electrode 200. This allows the second notched region 201 to balance the significant differences in wetting ability at various locations caused by the thickness differences between the second notched region 201 and the second non-notched region 202 of the active layer 400 of the second electrode 200.

[0089] Wherein, when the first electrode 100 includes a first region and a second region, determining the first notched region 101 based on the difference in thickness data of the active layer 400 at different positions of the first electrode 100 includes: When the thickness of the active layer 400 in the first region of the first electrode 100 is greater than the thickness of the active layer 400 in the second region, the first region is defined as the first etched region 101 and the second region is defined as the first non-etched region 102, so that the wetting ability of the first region and the second region of the first electrode 100 to the electrolyte tends to be consistent.

[0090] Similarly, when the second electrode 200 includes a first region and a second region, determining the second notched region 201 based on the difference in thickness data of the active layer 400 at different locations of the second electrode 200 includes: When the thickness of the active layer 400 in the first region of the second electrode 200 is greater than the thickness of the active layer 400 in the second region, the first region of the second electrode 200 is defined as the second etched region 201 and the second region is defined as the second non-etched region 202, so that the wetting ability of the first region and the second region of the second electrode 200 to the electrolyte tends to be consistent.

[0091] Wherein, when the first electrode 100 includes a first region, a third region, and a second region, determining the first notched region 101 based on the difference in thickness data of the active layer 400 at different locations of the first electrode 100 includes: When the thickness of the active layer 400 in the first region and the active layer 400 in the third region of the first electrode 100 are both greater than the thickness of the active layer 400 in the second region, the first region and the third region of the first electrode 100 are defined as two first notched regions 101, and the second region is defined as a first non-notched region 102, so that the wetting ability of the first region, the third region and the second region of the first electrode 100 to the electrolyte tends to be consistent. It should be noted that the first electrode 100 may be provided with multiple first notched regions 101 based on the difference in the thickness of the active layer 400 at various positions. The number of first notched regions 101 can be two, three, four, five and other positive integers, which are not listed one by one in the embodiments of this application, and the structure of the groove 500 of the first notched region 101 at different positions can be set differently.

[0092] Wherein, when the second electrode 200 includes a first region, a third region, and a second region, determining the second notched region 201 based on the difference in thickness data of the active layer 400 at different locations of the second electrode 200 includes: When the thickness of the active layer 400 in the first region and the active layer 400 in the third region of the second electrode 200 are both greater than the thickness of the active layer in the second region, the first region and the third region are each defined as two second notched regions 201, and the second region is defined as a second non-notched region 202, so that the wetting ability of the first region, the third region and the second region of the second electrode 200 to the electrolyte tends to be consistent. It should be noted that the second electrode 200 can be provided with multiple second notched regions 201 based on the difference in the thickness of the active layer 400 at various positions. The number of second notched regions 201 can be two, three, four, five and other positive integers, which are not listed one by one in the embodiments of this application, and the grooves 500 of the second notched regions 201 at different positions.

[0093] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0094] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0095] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0096] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. An electrode assembly, characterized in that, The electrode assembly is used in the same battery cell. The electrode assembly includes: a plurality of electrode sheets (10), the plurality of electrode sheets (10) including a first electrode sheet (100) and a second electrode sheet (200), the first electrode sheet (100) and the second electrode sheet (200) having the same polarity or opposite polarity; The first electrode (100) includes at least one first grooved area (101) and one first non-grooved area (102), and the second electrode (200) includes at least one second grooved area (201) and one second non-grooved area (202). Along the thickness direction of the electrode assembly, at least a portion of the first grooved area (101) and the at least one second grooved area (201) are offset from each other in the orthographic projection on the same plane.

2. The electrode assembly according to claim 1, characterized in that, Both the first electrode (100) and the second electrode (200) include a current collector (300) and an active layer (400), the active layer (400) being disposed on at least one side of the current collector (300), and the first etched area (101) and the second etched area (201) being located on the active layer (400).

3. The electrode assembly according to claim 2, characterized in that, The first electrode (100) includes m first groove regions (101), and the second electrode (200) includes n second groove regions (201), where m is greater than n or m is less than n.

4. The electrode assembly according to claim 2, characterized in that, The thickness data of the active layer (400) of the first electrode (100) is arranged in a wavy pattern along the length or width direction of the first electrode (100). The active layer (400) of the first electrode (100) includes at least one groove (500) disposed in the first etched area (101). At least one of the depth, length and width of the groove (500) varies with the thickness of the active layer (400). And / or, the thickness data of the active layer (400) of the second electrode (200) is arranged in a wavy pattern along the length or width direction of the second electrode (200), and the active layer (400) of the second electrode (200) includes at least one groove (500) disposed in the second notched area (201), and at least one of the depth, length and width of the groove (500) follows the thickness variation of the active layer (400).

5. The electrode assembly according to claim 4, characterized in that, The depth of the groove (500) increases as the thickness of the active layer (400) increases, and the depth of the groove (500) decreases as the thickness of the active layer (400) decreases.

6. The electrode assembly according to claim 2, characterized in that, The width of the first electrode (100) and the width of the second electrode (200) vary along the length direction of the electrode assembly; and / or, the length of the first electrode (100) and the length of the second electrode (200) vary along the width direction of the electrode assembly.

7. The electrode assembly according to claim 2 or 6, characterized in that, A tab (600) is provided on one side of the first electrode (100), and the first etched area (101) is located close to the tab (600) relative to the first non-etched area (102); And / or, a tab (600) is provided on one side of the second electrode (200), and the second etched area (201) is disposed close to the tab (600) relative to the second non-etched area (202).

8. The electrode assembly according to claim 2 or 6, characterized in that, The first electrode (100) has a tab (600) on one side, and the first etched area (101) is located away from the tab (600) relative to the first non-etched area (102); And / or, a tab (600) is provided on one side of the second electrode (200), and the second etched area (201) is disposed away from the tab (600) relative to the second non-etched area (202).

9. The electrode assembly according to claim 2 or 6, characterized in that, The first non-marked area (102) is configured to surround the first marked area (101), and the first marked area (101) is located in the central region of the first electrode (100); And / or, the second non-scratched area (202) is configured to surround the second scratched area (201), and the second scratched area (201) is located in the central region of the second electrode (200).

10. The electrode assembly according to claim 2, characterized in that, Both the first electrode (100) and the second electrode (200) include a main body (710) and an extension (720), the length of the extension (720) is less than the length of the main body (710), and an electrode tab (600) is provided on one side of the main body (710). At least a portion of the first scoring area (101) and / or the second scoring area (201) is located on the main body portion (710).

11. The electrode assembly according to claim 10, characterized in that, The first scoring area (101) and / or the second scoring area (201) include a first portion (810) and a second portion (820) connected to each other, the first portion (810) being located on the main body (710) and the second portion (820) being located on the extension (720).

12. The electrode assembly according to claim 2, characterized in that, Both the first electrode (100) and the second electrode (200) include a main body (710) and an extension (720), the length of the extension (720) is less than the length of the main body (710), and an electrode tab (600) is provided on one side of the main body (710). At least a portion of the first notched area (101) and / or the second notched area (201) is located on the extension (720).

13. The electrode assembly according to claim 2, characterized in that, Both the first electrode (100) and the second electrode (200) include a main body (710) and an extension (720). The length of the extension (720) is less than the length of the main body (710), and an electrode tab (600) is provided on one side of the extension (720). At least a portion of the first notched area (101) and / or the second notched area (201) is located on the extension (720).

14. The electrode assembly according to any one of claims 11 to 13, characterized in that, The ratio of the surface area of ​​the first etched area (101) or the second etched area (201) to the surface area of ​​the extension (720) is 0.3 to 1.

2.

15. A scoring method applied to the electrode assembly according to any one of claims 1 to 14, characterized in that, The scoring method includes: Obtain the thickness data of the active layer (400) at different positions of the first electrode (100); The first notched region (101) is determined based on the difference in thickness data of the active layer (400) at different locations of the first electrode (100). Obtain the thickness data of the active layer (400) at different positions of the second electrode (200); The second notched region (201) is determined based on the difference in thickness data of the active layer (400) at different locations of the second electrode (200). Wherein, along the thickness direction of the electrode assembly, the first etched area (101) and the second etched area (201) are offset in orthographic projection on the same plane.

16. The scoring method for the electrode assembly according to claim 15, characterized in that, The first electrode (100) includes a first region and a second region, and the determination of the first notched region (101) based on the difference in thickness data of the active layer (400) at different locations of the first electrode (100) includes: When the thickness of the active layer (400) in the first region of the first electrode (100) is greater than the thickness of the active layer (400) in the second region, the first region is defined as the first etched region (101), and the second region is defined as the first non-etched region (102). And / or, the second electrode (200) includes a first region and a second region, and the determination of the second notched region (201) based on the difference in thickness data of the active layer (400) at different locations of the second electrode (200) includes: When the thickness of the active layer (400) in the first region of the second electrode (200) is greater than the thickness of the active layer (400) in the second region, the first region is determined as the second etched region (201), and the second region is determined as the second non-etched region (202).

17. The scoring method for the electrode assembly according to claim 16, characterized in that, The first electrode (100) further includes a third region, wherein determining the first notched region (101) based on the difference in thickness data of the active layer (400) at different locations of the first electrode (100) includes: When the thickness of the active layer (400) in the first region of the first electrode (100) and the thickness of the active layer (400) in the third region are both greater than the thickness of the active layer (400) in the second region, the first region and the third region are defined as two first etched regions (101), and the second region is defined as a first non-etched region (102). And / or, the second electrode (200) further includes a third region, wherein determining the second notched region (201) based on the difference in thickness data of the active layer (400) at different locations of the second electrode (200) includes: When the thickness of the active layer (400) in the first region and the thickness of the active layer (400) in the third region of the second electrode (200) are both greater than the thickness of the active layer (400) in the second region, the first region and the third region are determined as two second etched regions (201), and the second region is determined as a second non-etched region (202).

18. A single battery cell, characterized in that, include: The electrode assembly as described in any one of claims 1 to 14; The housing contains the electrode assembly.

19. The battery cell according to claim 18, characterized in that, The battery cells include cylindrical cells, square cells, blade cells, or irregularly shaped cells.

20. A battery pack, characterized in that, The battery pack includes a plurality of battery cells as described in claim 18 or 19.

21. An electrical appliance, characterized in that, The electrical equipment includes the battery pack as described in claim 20.

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